steinmeyer_catalogue_ballscrews_16-25 mm - Setec

Welcome to where precision is.Large Ball ScrewsDiameter 16 - 125 mm106

Welcome to where precision is.Welcome to Steinmeyer!3

The production plant in Albstadt. In themidst of the 35.000m² wide factory is theoriginal building constructed by the founder.Together with the subsidiary companiesin Suhl and Dresden the Steinmeyer-Groupis a leading manufacturer of precision ballscrews and precision measuring equipment.© Bavaria Luftbild Verlag GmbHOUR PHILOSOPHYModern machine design places high demands on precision and reliability of its lineardrives. Ball screws, which have become an indispensable engineering element,require a high degree of product knowledge. And Steinmeyer is your key partner fordevelopment, production and application engineering.Small screws specifi cally prove Steinmeyer‘s expertise. Still setting standards after 40years, they have been developed to a degree of perfection second to none. Similarly,machine tool design expects continuously improving performance and life fi gures fromits linear drives. Steinmeyer is committed to being at the cutting edge - always.Such success is impossible without careful consideration of our customers‘requirements, which requires continued dialog with them. Experienced staff and thelatest equipment ensure we stay at the top - which our customers have come toexpect.In aerospace applications, precision has an additional signifi cance. It means applyingapproved processes over and over again - with not the slightest deviation. From rawmaterial to the fi nished component to its maintenance during the entire life cycle, fromdesign and development to qualifi cation testing - everything must be done in a wellcontrolled environment and an absolutely repeatable manner. On the ground as wellas in the air.5

Welcome to where precision is.AREAS OF APPLICATIONToday ball screws are used in a widelyvarying range of applications. Precisionball screws from 20 to over 100 mm indiameter are an indispensable elementfor positioning and infeed applicationsin today´s machinery and apparatusconstruction.The main challenge here is to providea dynamic and backlash-free powertransmission from rotational to linearmotion while keeping a high level ofstiffness and lifetime.Miniature ball screws with diametersof 16 mm and smaller are commonlyused for optical instruments, medicalengineering and other mechatronicapplications. Such applications requirethe lowest possible friction.Ball screws quite often have to survivespecial environments such as Ultra HighVacuum in electron microscopes orhigh temperatures during sterilization ofsurgical instruments.Ultra Thrust ball screws not only requirebigger dimensions but also need specialdesign solutions e.g. for injection moldingmachines or lifting tables.Contrary to that there are applicationsrequiring very fi ne adjustment. Smallestincrements, e.g. in analysis devices, areoften achieved using precision groundlead screws. Since screw shafts andnuts are matched to “nearly backlashfree” they often perform better comparedto other drive types.Applications in aerospace have quitedifferent demands on a ball screw. Firstof all there is uncompromising reliabilityunder all imaginable operating conditionswhile the precision issue takes a backseat.Of course design, manufacturing andtesting of aerospace ball screws has tobe continuously controlled to make surethat failure is impossible.6

Welcome to where precision is.PRECISION AT A GLANCETECHNOLOGYMINIATURE BALL SCREWSDIAMETER 3 - 16 MMLARGE BALL SCREWSDIAMETER 16 - 125 MMULTRA THRUSTBALL SCREWSDIAMETER 50 – 160 MMBALL SCREWS FORAEROSPACE APPLICATIONSROTATING NUTSPRECISIONLEAD SCREWSThis catalog contains the product range of Steinmeyer ball screws and is divided intoseveral product categories. Because it is not possible to show all special forms andmodifi cations please contact us to review your requirements. And please note thatnearly every other nut design, diameter / lead combination and ball size as well asaddi tional ball circuits are possible - as a custom unit. Please contact us for details.8

TECHNICAL INFORMATIONThe following chapters only show a small portion of the wide fi eld of applications for ball screws. In order to meet all the technicaland commercial demands for such a wide variety of different tasks, a deep understanding of the technology of ball screws is absolutelynecessary. We have collected extensive information about ball screws in this section of this catalogue and hope that youwill fi nd it useful.Please be aware that although we edited this information as carefully as possible, we cannot be held responsible for missing orincorrect information.PRECISION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 20Lead accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 15Friction torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 - 16General geometric tolerances (acceptance criteria) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 - 19Mounting tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 - 20PRELOAD AND RIGIDITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 – 26Nut designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 - 23Rigidity - stiffness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 – 26SERVICE LIFE CALCULATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 - 30Accounting for preload in the life calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 - 28Duty cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 - 28Equivalent load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 - 29Fatigue life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 - 30Load capacity according to ANSI standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 - 30MAXIMUM LOAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 - 33Buckling load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 - 32Fracture load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 - 33ROTATIONAL SPEED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 - 37Critical speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 - 35Maximum speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 - 36D Nvalue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 - 37BEARING JOURNAL DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 - 40Pre-tensioning a ball screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 - 39Select support bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 - 40LUBRICATION AND WIPERS / SEALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 - 48Tribology oil / grease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 - 43Oil lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 - 45Grease lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 – 48BALL RETURN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 - 49MATERIALS AND PROCESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 - 50DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 – 51NUMBERING SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 - 5211

TechnologyPRECISION (LEAD ERROR, FRICTION TORQUE, CRITICAL TOLERANCES)Under the headline „precision" DIN / ISO standards are explained as they apply toball screws, how accuracies are defi ned, and the acceptance or specifi cation criteriaderived from these standards.Lead accuracyFriction torqueRoundness, concentricity and squareness of relevant surfacesLEAD ACCURACY PERDIN 69051 / ISO 3408In general, all acceptance criteria should be reviewed and agreed upon between Steinmeyerand our customer. This is especially relevant for those applications where specialdemands are required, for example a lead accuracy of class 5 but friction torquevariation consistent with accuracy class 1. In this example, Steinmeyer produces aball screw with economical class 5 lead accuracy but with much lower friction torquevariation. Both DIN and ISO standards use the following terms and defi nitions to describe leadaccuracy. The corresponding JIS designations are given in parentheses:Lead compensation c is used to compensate lead errors resulting from thermalgrowth or pre-tensioning of the ball screw shaft (JIS: T).The permissible lead deviation e pis an averaged lead error over the entire usefultravel (JIS: E)The permissible lead fl uctuation v upover the entire useful travel is defi ned as thevertical distance of two straight lines parallel to the line representing e pwhichenclose the entire lead error graph (JIS: e).The lead fl uctuation v 300prepresents the same for any 300 mm interval (JIS: e 300).And fi nally the lead wobble v 2πpis the lead error within one revolution (JIS: e 2π).Ball screws are normally categorized in accuracy classes, which not only defi ne leadaccuracy, but a number of different quality criteria like squareness and concentricity ofmating surfaces, shaft straightness, friction torque fl uctuation etc. Although this seemsto be a trouble-free approach, ball screw users often choose to specify these othercriteria by defi ning them in the source control drawing, while using ISO or DIN standardaccuracy classes to only describe lead accuracy.Steinmeyer uses accuracy classes 1, 3, 5, 7 and 10 per ISO / DIN standard. Accuracyclasses 0, 2 and 4 are not contained in these standards, but have been added tomatch the JIS 1902 standard.12

Positioning ball screwsTransport ball screwsPTThe DIN standard differentiates between positioning ball screws and transport ballscrews.Positioning ball screws are normally used in high-precision applications (like machinetool) and are usually equipped with a ground ball thread.Transport ball screws are predominantly used for travelling and moving applications.Typical applications are axes for handling systems. Ball thread of such screws isusually rolled or whirled.Per DIN standard the tolerance classes for positioning ball screws aredescribed as "P" while the transport ball screws classes are described as "T".Steinmeyer uses this designation as per DIN:P0 – P5 for positioning ball screwsT5 – T10 for transport ball screwsLead error overthe entire useful traveldeviationtravelLimit e p for the average lead error e 0a[μm]l u[mm]Tolerance classfrom to P0 P1 P2 P3 P4 P5 T7 T10- 200 3 5 7 10 15 20200 315 4 6 8 12 18 23315 400 5 7 9 13 19 25400 500 6 8 10 15 21 27500 630 6 9 11 16 23 30630 800 7 10 13 18 27 35800 1000 8 11 15 21 31 401000 1250 9 13 18 24 35 461250 1600 11 15 21 29 42 541600 2000 - 18 25 35 50 652000 2500 - 22 30 41 59 772500 3150 - 26 36 50 72 933150 4000 - 32 44 62 88 1154000 5000 - - - 76 108 1405000 6300 - - - 92 131 170l ue p = 2 .300. V 300pTECHNICAL TIPThe lead error e p is defi ned via a straight line, which represents the optimum approximation of the actual lead error graph. Thisline will then be shifted parallel so it crosses the origin of the axis. This means that there can be a deviation at the beginning ofthe travel. Also, the lead error at the end of travel can actually be greater than the maximum permissible error as long as theaverage lies within the tolerance limits!Nevertheless, a defi nition of the lead accuracy via e p is a stronger criteria than the commonly used deviation per 300 mm, becausethe error may not be accumulated. For example, the maximum permissible lead error e p of a screw 900 mm long is lessthan three times the permissible error in 300 mm.13

TechnologyPRECISIONLead error fluctuation over entiretravel Limits v upfor the variation v ua[μm]l u[mm]Accuracy class [¹ n/a for rolled and whirled ball screws]from to P0 P1 P2 P3 P4 P5 T7 T10- 200 3 5 7 10 15 20 1 - -200 315 4 6 8 12 18 23 1 - -315 400 4 6 8 12 19 25 1 - -400 500 4 7 8 13 20 26 1 - -500 630 4 7 8 14 22 29 1 - -630 800 5 8 9 16 24 31 1 - -800 1000 6 9 10 17 26 35 1 - -1000 1250 6 10 11 19 29 39 1 - -1250 1600 7 11 13 22 33 44 1 - -1600 2000 - 13 15 25 38 51 1 - -2000 2500 - 15 18 29 44 59 1 - -2500 3150 - 17 21 34 52 69 1 - -3150 4000 - 21 25 41 62 82 1 - -4000 5000 - - - 49 74 99 1 - -5000 6300 - - - 58 88 119 1 - -TECHNICAL TIPThe fl uctuation of the lead error is defi ned by two lines parallel to the line representing the average lead error, which include theentire lead error graph.The lead error fl uctuation is applicable to precision ground positioning screws in accuracy classes 0 - 5 only. It does not applyto general purpose screws which are typically either rolled or whirled in classes 5 - 10.Lead error fluctuation per 300 mm The variation over 300 mm is the most common defi nition. However it is also importantto know whether the allowed variation is cumulative, or not. If the allowable variationis specifi ed as "cumulative" then the permitted error over the full travel of a screw canresult in a total error which is equivalent to the next lower accurancy class. Example:Stroke 900 mm, accuracy class P3, 3 x 300 mm would result in a total deviation of 3 x12 μm = 36 μm. This result is equivalent to the total error of accuracy class P5 (35 μm)!However, the admissible deviation e p for such a screw in accuracy class P3 is 21 μm.Limits v 300pfor the fluctuation v 300a[μm]Accuracy classP0 P1 P2 P3 P4 P5 T7 T104 6 8 12 18 23 52 21014

Lead error fluctuation overone revolution (lead wobble)The variation of the lead within one revolution, the so-called wobble-error usually issinusoidal. Here the DIN standard allows relatively coarse tolerances. If needed, thistolerance can be restricted.deviationtraveln.2πradLimit v 2πp for the lead error v 2πa [μm] [¹ n/a to rolled or whirled ball screws]Accuracy classP0 P1 P2 P3 P4 P5 T7 T103 4 5 6 7 8 1 - -v 2πpv 2πaBall screws are globally defi ned by the ISO standard 3408, which is compatible to DIN69051 to a large extent. In Japan the JIS 1902 standard is valid while in the USA theANSI standard B92.1 is still occasionally used.Concerning nut dimensions, the ISO standard has achieved acceptance, at leastwhere nuts are equipped with the space-saving internal defl ection system.Quite often old data or specifi cations from other standards are used to defi ne a ballscrew. Therefore, please be cautious when trying to directly compare parameters suchas load capacity or stiffness.While JIS and ISO standard are quite similar when describing accuracies or load capacities,the ANSI standard is quite different, especially regarding load capacity.Steinmeyer exclusively uses the ISO defi nitions.15

TechnologyPRECISIONTOLERANCE OF TORQUEThe friction torque tolerance is solely defi ned for preloaded ball screws with doublenuts and is mainly affected by the accuracy class, preload value and diameter/lengthratio of a ball screw. The permissible torque fl uctuation is given in % based on thenominal idling torque of a preloaded ball screw.Variation of friction torquetorquetravelFriction torque(nominal)T pr0[Ncm]Friction torque variation in [%]For short screws (L ≤ 40 · d N)For longer screws see table below!Accuracy classfrom to P0 P1 P3 P5 T75 10 40 45 50 60 -10 20 35 40 45 50 -20 40 30 35 40 50 -40 60 25 30 35 40 -60 100 20 25 30 35 40100 250 15 20 25 30 35250 630 10 15 20 25 30630 1000 - - 15 20 30Friction torque(nominal)Friction torque variation in [%]For long screws (L ≥ 40 · d N)T pr0[Ncm]Accuracy classfrom to P0 P1 P3 P5 T75 10 - - - - -10 20 50 50 60 60 -20 40 40 40 50 60 -40 60 35 35 40 45 -60 100 30 30 35 40 45100 250 25 25 30 35 40250 630 20 20 25 30 35630 1000 - - 20 25 35The values of the interclasses can be determined by interpolating.TECHNICAL TIPSteinmeyer can provide a friction torque chart for preloaded ball screws upon request (for an extra charge!). The test methoddescribed in the ISO / DIN standard is to run the ball screw, with a thin fi lm of oil, at 100 rpm and without wipers. Other testmethods can be agreed upon. The values shown here apply to the test method per ISO / DIN standard.Tolerances for the friction torque of preloaded single nuts are specifi ed individually.Aerospace ball screws are often tested for idling torque, although they are normally not preloaded. This test serves to determineproper operation of wipers and seals. This test can be part of the ATP; it is normally done with the ball nut greased and readyfor shipment.16

GENERAL GEOMETRIC TOLERANCES(ACCEPTANCE CRITERIA)The values listed below represent general rules for run-out tolerances of ball screws.For specifi c applications tolerances may vary.Tolerances of run-outand perpendicularitySteinmeyer recommends supporting the screw using the outside diameter for all inspectionof geometric tolerances. This will ensure optimum repeatability of the measurement.In some cases the center holes are used as reference.AA‘AA‘AAA‘A‘AA‘Run-out tolerancesRun-out Tolerance t 5Pof the shaft outside diameter for the length l 5(the shaft straightnesswith reference to AA') - according to DIN 69051 part 3 or ISO 3408-3.tl 5pAA‘5l 5l 5AA‘2 d N2 d Nl 1l 5l 5d NRun-out tolerance t 5Pfor the length l 5[μm]Accuracy classfrom to l 5P1 P3 P5 T7 T103 12 8012 25 16025 50 315 20 25 32 40 8050 100 630100 200 1250Run-out tolerance t 5 maxfor the length l 1≥ 4l 5[μm]l 1/ d NAccuracy classfrom to P1 P3 P5 T7 T1040 40 50 64 80 8040 60 60 75 96 120 24060 80 100 125 160 200 40080 100 160 200 256 320 64017

TechnologyPRECISIONRun-out t 2Run-out t 2[μm]Nominal-∅Accuracy classd N[mm] P0 P1 P2 P3 P4 P5 T7 T103 - 6 5 7 7 8 10 - - -8 - 10 5 7 7 9 10 10 20 -12 5 7 8 9 10 10 20 -16 - 20 5 7 9 10 12 13 20 -25 - 32 6 8 10 11 12 14 25 -36 - 50 7 9 12 13 15 16 25 -60 - 125 8 10 13 14 16 18 25 -Run-out t 3Run-out t 3[μm]Nominal-∅Accuracy classd N[mm] P0 P1 P2 P3 P4 P5 T7 T103 - 6 3 4 6 7 8 10 - -8 - 10 4 5 7 8 9 11 12 1512 4 5 7 8 9 11 13 1716 - 20 4 6 8 9 10 12 15 1825 - 32 5 7 9 10 12 13 16 1936 - 50 6 8 11 12 14 15 18 2160 - 125 7 9 12 13 15 17 20 23Perpendicularity t 4Perpendicularity t 4[μm]Nominal-∅Accuracy classd N[mm] P0 P1 P2 P3 P4 P5 T7 T103 - 6 2 2 2 3 3 3 - -8 - 10 2 2 2 3 3 4 5 712 2 2 2 3 3 4 6 816 - 20 2 3 3 4 4 5 7 925 - 32 2 3 4 4 4 5 7 936 - 50 2 3 4 4 4 5 7 960 - 125 3 4 5 5 6 7 10 1318

Perpendicularity t 5Perpendicularity t 5[μm]Nominal-∅Accuracy classd N[mm] P0 P1 P2 P3 P4 P5 T7 T103 - 6 6 7 8 9 9 10 - -8 - 10 6 7 8 9 9 10 15 -12 6 7 8 9 9 10 20 -16 - 20 7 8 9 10 10 12 25 -25 - 32 7 8 9 10 10 12 32 -36 - 50 8 9 10 10 12 13 32 -60 - 125 9 10 11 12 13 15 40 -Run-out t 6Run-out of pilot diameter t 6[μm]Nominal-∅Accuracy classd N[mm] P0 P1 P2 P3 P4 P5 T7 T103 - 6 5 6 7 8 9 10 - -8 - 10 5 6 7 8 9 10 20 -12 5 6 7 8 9 10 20 -16 - 20 5 6 7 8 9 10 20 -25 - 32 5 6 7 8 9 10 20 -36 - 50 6 7 8 8 10 11 25 -60 - 125 7 8 9 10 12 13 32 -Steinmeyer‘s specified parameters for concentricity and perpendicularity areconsiderably lower compared to the DIN values.TECHNICAL TIPSteinmeyer recommends supporting the screw by using V-blocks for all inspection of geometric tolerances. This will ensureoptimum repeatability of the measurement. If necessary, dual gages can be used to measure the concentricity of two surfaceswith respect to one another, e.g. the concentricity of drive journal and bearing journal. This measuring method includes the perpendicularityand run-out tolerance of the nut already.19

TechnologyPRECISIONMOUNTING TOLERANCESTECHNICAL TIPSteinmeyer recommends maintaining the mounting tolerances shown on this page. Optimum alignment of the screw with theguideways and square and concentric mounting of the nut will ensure proper operation of the drive system and long life of theball screw.After installation, check that the screw spins freely and without excessive friction over its entire travel. If there is any binding orconsiderable increase in effort necessary to turn the screw, especially near the support bearings, this indicates the alignment ofthe screw and the guideways should be improved. Binding indicates excessive side loads which can and will shorten the servicelife of the ball screw unless corrected.PerpendicularityAB0.02 A - B P 1 - 50.03 A - B T 70.05 A - B T 10ParallelismAB0.02 A - B P 1 - 50.03 A - B T 70.05 A - B T 1020

PRELOAD AND RIGIDITYNUT DESIGNSThis section deals with the various nut types and their preload. We also explain thedifferent rigidity (stiffness) values.TECHNICAL TIPPreload primarily serves to eliminate play. But at the same time preload increases rigidity, which means the displacement of thenut under load is reduced.Another reason why preload may be necessary is to prevent balls from skidding during high acceleration, or to ensure better loaddistribution if side loads on the ball nut cannot be avoided.There are a number of ways to preload a ball nut. For a discussion of preload and its effects we have to fi rst distinguish betweenpreload with two contact points per ball (one in the nut, one in the shaft), and preload with 4-point contact (two contact pointsin the nut and two in the shaft), which requires the use of a „gothic arch" profi le.Steinmeyer always uses a gothic arch profi le, so both kinds of preload are possible.Single nut with 4-point-contactSingle nuts, as defi ned by Steinmeyer, are one-piece nuts without any shift or offset intheir I.D. ball thread. They can only be preloaded by ball oversize and will always have4-point contact. This differentiates them from all other preloaded nuts and their 4 pointcontact has an impact on technical data and some calculations.4-point contact infl uences the kinematics of the balls with the following results:Effi ciency of a single nut with preload is always somewhat lower than thatof a double nutSingle nuts with preload show a more pronounced reaction to manufacturingtolerances, which is why they are normally not suitable for very long screwsCaution: these statements are only true for single nuts with preload. Without preload,single nuts have 2-point contact with the same ball kinematics as double nuts!Advantages of the single ball nut are:Cost effectivenessCompact envelopeNo unloading of balls when subjected to peak loads (see preload chart)21

Welcome to where precision is.PRELOAD AND RIGIDITYDouble nut (UNILOCK)Double nuts from Steinmeyer do not depend on the usual spacer ring or other hardwareto separate the two nuts. Our patented UNILOCK coupling ensures a robustconnection of the two nut halves. Thus Steinmeyer‘s double nut is almost as compactand stiff as a single-piece design. Moreover, it prevents radial slippage of the twohalves, so the UNILOCK double nut cannot be misaligned by rough handling. Thecoupling is rugged and absolutely tight to prevent loss of lubricant.Advantages of a double nut are:2-point contact for higher rigidity and effi ciencySimplifi ed production compared to lead-offset nuts when the nut is long and helixangles are largeEasier factory setting of preload without changing of balls, thus economicalDisadvantages are:Longer nut body compared to single nuts, and somewhat higher costAs in all nuts with 2-point contact, the maximum thrust should not exceed2.8 times the preloadTECHNICAL TIPSteinmeyer labels all ball nuts that have 2-point ball contact a „double nut", regardless whether the nut body is made of two piecesor one. This defi nition makes sense because both of these nuts have very similar properties, and because all life calculationsfor these nuts are done in the same way. 4-point contact ball nuts on the other hand require different calculations, specifi callyhow preload is handled in the life calculations.Steinmeyer‘s patented UNILOCK coupling of two-piece double nuts results in a connection that is nearly as stiff and compact as asingle-piece nut. This is why we do not distinguish between single-piece double nut design (the lead-offset nut) and a two-piece design(UNILOCK double nut) in this catalog. Steinmeyer will select whatever design is most suitable for the particular size of ball nut.Allnuts with 2-point contact can be recognized by the „5" in the 2nd number of their series designation (for example 1516, 3526 etc.).Lead-offset nutWhen preloading a UNILOCK double nut, the two halves are rotated relative to eachother until the balls are slightly compressed. Thus the threads of the second nut areno longer directly „in phase" with the threads of the fi rst nut. There is a slight offsetbetween the two nut halves.The lead offset nut uses the same principle but the offset is created during machiningof the threads in a nut made from a single piece of steel. Fine tuning of the preload isthen accomplished by selecting „oversized" balls like in a single nut. Due to the offset,balls have 2-point contact.22

Advantage: Slightly more compact than a double nut (shorter length)Disadvantage: More threads have to be machined from one end of the nut. Especiallyin nuts with many turns and large helix angle, grinding I.D. threads canbe diffi cult or even impossibleNB: Steinmeyer often uses hard turning for such long nuts, eliminating the problemsassociated with long and relatively weak grinding arbors.Pitch-offset nutLike the lead-offset nut, the pitch-offset nut uses a shift machined in the I.D. threadsto enable 2-point contact of balls. The only difference is that the pitch-offset nut usesa two-start thread and the offset is between the two starts.Each thread start has its own set of balls and ball returns.Advantage: Pitch-offset nuts are extremely compactDisadvantage: Pitch-offset preload can only be used in nuts with two (or more) startsSpring preloaded double nutAlmost exclusively used with miniature ball screws, the spring preload maintains perfectlyconstant preload regardless of wear and manufacturing tolerances. Two nuts are installedin a housing. One is fi xed, while the second one can slide longitudinally (a pin keeps it fromrotating). A spring located in between the two nuts keeps the preload constant.The advantages are obvious:Manufacturing tolerances will have no impact on preload and frictionPreload can be very light and the ball nut will never have play regardless of wear etc.There are also some disadvantages:The double nut with its housing is bulkier and more expensiveThe slip-fi t of the second nut makes alignment more challengingThe maximum thrust is limited by the spring - when exceeded, the spring willcollapse causing play in the nutTECHNICAL TIPThe spring preloaded nut excels when it is not possible to keep manufacturing tolerances low enough to ensure very low andconstant friction. This is the case when near zero friction is necessary while at the same time absolutely no play is acceptable,or if the screw is extremely long.Please be aware that the spring preloaded nut has a maximum operating force equal to about 2/3 of the preload. We can increasepreload to some degree upon request, but if peak loads exceeding the preload force cannot be avoided, then a single nutwith rigid preload is preferred (miniature screw series 1112, 1214, 1412).23

TechnologyPRELOAD AND RIGIDITYSTIFFNESSTECHNICAL TIPHigher preload results in increasedrigidity. But rigidityincreases only with the cubicroot of preload. To comparestiffnesses based on differentpreload settings, multiply rigidityvalues by the cubic rootof the ratio of the preloads.For example:R 2= R 1·F3 pr2F pr1where F pr1 and F pr2 are thepreload settings to be compared,and R 1 and R 2 are thecorresponding rigidities.The rigidity of a ball screw not only has a strong impact on positioning accuracy, butalso plays an important role concerning the dynamic behavior of a linear drive. Theimportance to the latter is normally underestimated.Rigidity according to ISO 3408 or DIN 69051 is a value labeled R b/t . This value isobtained from theoretical elastic deformations obtained from the theory of Hertzianpressure with the variables of track conformity, contact angle and the number ofload carrying balls. R b/t is a relatively high number.When the deformation of the nut body (diameter widening, longitudinal expansion) isincluded, the value is labeled R nu , and is already signifi cantly lower than R b/t .To obtain a real value, the theoretical vaule of R nu has to be corrected further, sincenot all balls carry the same load. Depending on the accuracy grade of the ball screw,the correction factor varies. The reduced value, which is closer to reality and measurable,is designated R nu,ar .Steinmeyer publishes only R nu,ar values in our catalog and on our website. Please besure to compare these values only to similarly defi ned rigidities from other manufacturers,and also ensure that the comparison is based on the same preload value you wantto use (see technical tip regarding the impact of preload on rigidity).Rigidity of the nut and preloadBesides number and size of loaded balls, track conformity and contact angle, the maindriver for the rigidity of the nut is preload. However, the possibility to signifi cantly increaserigidity by raising preload is very limited because rigidity increases only as the cubic rootof preload. But the increase in heating is directly proportional plus the reduction of servicelife is substantial since preload increase is raised to power three in the life equation.This is why preload should not be set too high: For a nut with 2-point contact, 10% of thedynamic load capacity is a reasonable number. Nuts with 4-point contact should not bepreloaded to more than approximately 8% of their dynamic capacity.Steinmeyer publishes rigidity values for these preload settings:10% C afor nuts with 2-point contact (series x5xx)8% C afor nuts with 4-point contact (series x4xx)Make sure when comparing with other manufacturer‘s rigidity data to check not only thedefi nition of terms but also that the comparison is done using the same preload.24

TECHNICAL TIPAccording to the ISO / DIN standard, the nut theoretical stiffness R nuis converted into the actual nut stiffness R nu,arby applying acorrection factor which depends on the accuracy class of the ball screw. For example a ball screw with accuracy class 1 wouldbe more rigid than a screw of otherwise same design with an accuracy class 5. The reason for this is that better geometric tolerancesof a more accurate screw, e.g. the lead wobble, result in more even ball loading.Upon request (and extra cost), Steinmeyer will provide rigidity test protocols with every screw.for better rigidity - static and dynamicball screws are not only signifi cantly more rigid in a classic sense, which only considersthe elastic deformation of a stationary screw under varying axial loads. They alsohave a much better „dynamic stiffness", which means that the screw has a „linear behavior"and delivers an axial movement perfectly proportional to its rotation, regardless ofthrust, speed and direction. Even reversing will not cause deviations from this.This linearity is especially signifi cant in closed-loop controls, allowing considerably increaseddynamics with substantially reduced following error. Unfortunately, this is not yetrefl ected in current ISO or DIN standards.Rigidity of the screwThe screw stiffness depends on the elasticity modulus of the screw material, crosssectional area of the screw and the unsupported screw length.Fixed-free mountingOn fi xed-free bearing confi guration the screw stiffness is calculated as follows:ER s1= A · ·10 -3l sFixed-fixed mountingThis is the calculation of the rigidity for fi xed-fi xed mounting method:R s2=2·A· ·10 -3 El s2A: Screw cross section [mm 2 ]E: Young´s modulus [N/mm 2 ](for DIN 1.1213 = 210,000 N/mm 2 )25

TechnologyPRELOAD AND RIGIDITYTotal rigidity of a linear driveElasticity of a linear drive includes elastic deformations of thrust bearings, ball screwshaft and ball nut. This total, based on the „inverse" equation below, is what matters tothe performance of the drive. But only the nut stiffness is normally given in the technicaldata of a ball screw.R t=11 1 1+ +R nu,arR sR bR t: Total rigidity [N/μm]R nu,ar: Actual nut rigidity [N/μm]R s: Stiffness of the screw shaft [N/μm]R b: Axial stiffness of the thrust bearing [N/μm]The rigidity of the thrust bearing can be obtained from the literature of the manufacturer.Rigidity of the screw shaft can be calculated from the elasticity modulus of steel(210,000 N/mm 2 ), the shaft‘s cross section and the length of the loaded portion of theshaft. For screws with large lead / diameter ratio, torsion also plays an important roleand must be considered as well.If you want to do the calculation of axial and torsional stiffness yourself, just use thenominal diameter of the ball screw minus the ball diameter to calculate the cross sectionand moment of interia. Or, contact us and we will do this for you.TECHNICAL TIPInstalling thrust bearings at both ends of the screw yields four times the axial shaft stiffness compared to a single thrust bearingat one end and no support on the opposite end. A factor of 2 results because forces are transmitted through the shaft on bothsides of the nut. A second factor of 2 also applies because the weakest point is now in the middle of the shaft rather than at theextreme end.Thrust bearings at both ends normally require pre-tensioning the screw, against the support bearings, in order toavoid compressive loads on the shaft from thermal expansion (which may cause buckling). Make sure to check the impact thisadditional force has on the bearing life.Linear drives with rotating nut and stationary screw allow a simple way of increasing torsional stiffness of the shaft by transmittingmoments into the surrounding structure at both ends of the shaft. Then the same effect as described above applies to thetorsional stiffness: A factor of 2 for twice the cross section, and again a factor of 2 for half the distance to the weakest point.26

SERVICE LIFE CALCULATIONSBall screws are normally loaded with axial forces. Service life is determined by materialfatigue in most cases. However, in some applications, abrasive or adhesive wear maycause a loss of preload and thus be considered a failure of the ball screw.In the ISO 3408 or DIN 69051 standards, the math used to estimate ball screw life isbased on material fatigue only. This is generally correct, but if the loading is very lowand mean speeds are very high, this method may return an erroneous life estimationwhich cannot be reached in reality. If your application falls within this category, pleaseconsult our engineers.ACCOUNTING FOR PRELOAD IN THELIFE CALCULATIONIn this step, we modify axial forces to refl ect the impact of preload. The preload graphshows how internal forces in the ball nut are affected by external forces and preload.The preload graph includes two lines which represent the forces and resulting defor-Preload graphmation for both nut halves in a double (or pitch shift) nut. The center of the chart, wherethe two lines cross, shows the situation of the nut with no external forces. Both nuthalves carry the same load - which is the preload F pr.ForceForceTensioning nutLoad carrying nutIf an external force is added, then the load in one nut increases, while it decreases inthe other. The resulting difference of the two forces is equal to the external load.DeflectionDeflectionload carrying nuttensioningnutload carrying nutThe load in each nut can be read from the two lines and this load is to be used for lifecalculations. As a simple approximation, the nut with the higher load has to carry thepreload plus approximately half of the external load. Using this approximation for F i* isaccurate enough.Calculating modified loads for nutswith 2-point-contactF i*=FFpr +i2As a quick and simple approximation for the internal load in nuts with 2-point contact,just add or subtract half of the external thrust F i to or from the preload F pr. Whetheryou call a certain thrust direction positive or negative does not matter. But you haveto keep this direction orientation the same for the whole duty cycle. The nut with thehighest load then determines service life.F i*:F pr:F i:Modifi ed external load [N]Preload [N]External load [N]27

TechnologyCalculating modified loads for nutswith 4-point contactF i5F i*= Fpr +4 2When calculating modifi ed loads for nuts with 4-point contact, all external thrust has tobe added regardless of load direction. The factor of 1.25 (5/4) is necessary to accountfor the fact that the balls have 4 contact points, causing fatigue much sooner than in anut with 2 contact points. This approximation is accurate enough in cases with normalloads and duty cycle.THE DUTY CYCLE AND ITSEQUIVALENT LOADTo calculate the impact of actual duty on the fatigue life of the ball screw, it is necessaryto convert the varying loads F iinto a mean load F mwhich will have the same effect onlife as the actual duty cycle. This mean load Fm is therefore called „equivalent" load.To simplify things, the actual duty is normally divided into steps. Then the maximumthrust (or, if the ball screw is preloaded, its modifi ed load), speed and duration are usedto calculate the equivalent load. Instead of using time and speed n i·q i, the absolutenumber of revolutions can be used in this calculation.n [rpm]TECHNICAL TIPThe duty cycle of machine tools is normally provided as:x 1% Rapid with thrust y 1x 2% Roughing with thrust y 2x 3% Finishing with thrust y 3x 4% Dwelletc. Such values can be modifi ed to refl ect preload and then directly entered into the equation for F m.If the duty cycle provided includes a detailed description of moves, the respective revolutions can be entered instead of q i·n i28

EQUIVALENT LOADF m=33 3 3q 1 · n 1 · F 1+ q 2 · n 2 · F 2+…+ q n · n n · F nq 1 · n 1+ q 2 · n 2+…+ q n · n nn m= q 1 · n 1 + q 2 · n 2 +…+ q n · n nq 1+ q 2+…+ q nThe mean or equivalent load is calculated using the above equation.F m: Dynamic equivalent load [N]n m: Equivalent speed [rpm]q i: Time percentage [%]n i: Speed [rpm]F i: Thrust (which may need to be modifi ed - due to preload - fi rst) [N]The service life estimate obtained from ISO / DIN calculations represents a dependablemethod to predict useful life of a ball screw under the conditions and for the dutycycles found in most machines. Other necessary conditions include proper lubrication,suitable protection from contamination, and operation of the ball screw at temperaturesnot exceeding 70° C.Should the calculated life fall outside the range mentioned on the following page, or ifthere are special requirements or unusual conditions, please contact our applicationengineers.TECHNICAL TIPBy defi nition, the dynamic load capacity is the load at which the ball screw will reach a useful life of 1 million revolutions.More accurately, this means 90% of a suffi ciently large number of identical ball screws will reach this useful life. This life is designatedas L 10and is usually the basis for ball screw selection in normal machine design. For higher reliabilities than 90%, anadditional correction factor must be applied. In regular machine design, such higher reliabilities are normally not needed becausethere are much greater uncertainties, for example in the estimate of thrust.FATIGUE LIFEF m=C aL3 1010 6F m:Permissible mean load for a given dynamic load capacity and life [N]C a=F m·3L 1010 63C aF mL 10 = ·10 6C a:L 10:Dynamic load capacity required for a given mean load and life [N]Fatigue life for a given dynamic load capacity and mean load [revolutions]29

TechnologyThe useful life L 10 can be expected to be reached by 90% of a suffi ciently large numberof identical ball screws having a load capacity C a , when subjected to the mean load F m .As an example, the life L 5 , which is 62% of L 10 , will be reached by 95% of the ballscrews. Aerospace applications require a more detailed reliability analysis, for which theFMEA (Failure Mode and Effects Analysis) and fault trees are used to determine MTBF(Mean Time Between Failure) or MTBUR (Mean Time Between Unscheduled Removal).Reliability(probability ofsurvival)90 % 95 % 96 % 97 % 98 % 99 %Correction factor 1 0.62 0.53 0.44 0.33 0.21TECHNICAL TIPCalculation of the life expectancy is based, according to ISO / DIN standards, on Hertzian pressure. Theoretical load capacitiesare then modifi ed with factors derived from experience. These corrected values allow very dependable predictions of ball screwlife, under normal conditions, if the calculated life expectancy falls within this range:3 · 10 7 ≤ L 10≤ 10 9 [revolutions]ANSI load capacity: According to ANSI ball screw standards, the dynamic load capacity is the load whereby the ball screwreaches a life of 1 million inches of travel (ISO/DIN: 1 million revolutions). For a direct comparison with ISO/DIN numbers, theANSI load capacity must be converted as followsLOAD CAPACITY ACCORDING TOANSI STANDARDAccording to the ANSI standard, dynamic load capacity of a ball screw is the load underwhich it will reach a life of 1 million inches of travel. If the lead is smaller than 1 inch,then the load capacity per ANSI defi nition is smaller than the load capacity of the sameball screw expressed according to ISO / DIN standard. This is because the ANSI loadcapacity defi nes a load for which the resulting life in this case (lead less than 1 inch) isgreater than 1 million revolutions.C a= P i · 4.45 ·C a: DIN / ISO-load capacity [N]P i: Load capacity per ANSI [lbf]P: Lead [mm]325.4PThe opposite holds true for a ball screw with lead larger than 1 inch. For such a case,the ANSI load capacity will be higher than the ISO load capacity, although the ballscrew itself is identical!To compare load capacity of a ball screw per ANSI standard to one per ISO / DIN standard,a conversion must be made. This equation will also convert lbf into Newtons:TECHNICAL TIPPreload is usually defi ned as a percentage of dynamic load capacity. Nuts with 4-point contact normally have a preload of 5 - 8%of dynamic load capacity, while for nuts with 2-point contact it is 8 - 10%. Keep in mind this refers to ISO/ DIN load capacity only.If the ANSI standard is used, then the percentages may change!30

MAXIMUM LOAD (LIMIT LOAD)There are fi ve ways a ball screw may fail due to overload:Excessive dynamic loading, which means the screw makes too many revolutionsunder a certain load resulting in material fatigue. This can be avoided by selecting aball screw with suffi cient dynamic load capacity (or by reducing the number of revolutionsand/or reducing the load). This is the subject of the load capacity discussion.Exceeding the static load capacity, which causes instant and permanent damage tothe ball screw due to brinelling of balls and races, and prevents any further normaloperation of the ball screw. Static load capacities are listed as technical data.Buckling of the shaft under compressive load. Buckling load value depends on bearingmethod and free length of the loaded ball screw shaft.Failure of the nut body or of the bolts that connect it to the slide. This may happeneven before the static capacity is reached. Safe loads are discussed on the followingpages.Radial loads. It means the load capacities given in this catalogue apply only to pureaxial loading. As there are always tolerances in the alignment of bearings and linearguideways, there may be a small amount of radial force, which should be minimized.Under normal conditions, a radial load less than 5% of the minimum axialload will not cause any problems. When considering a ball screw for use under radialload, please consult Steinmeyer engineers.TECHNICAL TIPA reasonable load for a ballscrew, which may be sustained for signifi cant travel, is about 10% of its dynamic capacity.A mean load of 10% of its dynamic capacity results in a theoretical life of 1 billion revolutions, which is the upper limit of the rangewhere the life equation is valid. Mean loads of a reasonably sized ball screw will therefore be somewhat higher than this, butnormally not exceed 20% of its dynamic capacity.For short peak loads, the loading may be higher, but normally the loading of a ball nut with 2-point contact should not exceed2.8 times the preload. And preload is around 5% - 10% of dynamic capacity.As a rule of thumb, this all means the load range for a ball screw is really about 10% to 30% of its dynamic capacity.BUCKLINGThere are several analytical ways to demonstrate safety from buckling. In machine design,the most frequently used is a simple calculation using formulas based on Euler equations.Other, more accurate methods include non-linear FEM analysis and more involvedmathematics. These methods are normally used in aerospace applications, whereexcess safety margins are not possible due to weight limitations. Please contact us ifyou require such an analysis.On the following page we describe a simple form of buckling analysis.31

TechnologyTECHNICAL TIPBecause of the logarithmic scale on the chart below, data for long screws or screws with large diameter may be diffi cult to read.You may prefer to use this equation instead:P B =24m · d Nl s· 10 4P B: Buckling [N]d N: Nominal-Ø [mm]l s: unsupported screw length [mm]m: bearing coeffi cientThe following factors refer to the bearing methodsshown in the chart. Choose the appropriateone and use it as the variable m in theequation to the left:Fixed - fi xed (1): 22.4Fixed - supported (2): 11.2Supported - supported (3): 5.6Fixed - free (4): 1.4For safety reasons, a factor of 0.5 should be applied to the buckling load obtained.F max= 0.5 · P BBuckling load [kN]Length of unsupported shaft I s [mm]32

MAXIMUM LOAD (LIMIT LOAD)FRACTURE LOADSome ball screws cannot be loaded all the way to their static capacity. Screws with highdynamic load capacity (which might be selected to obtain a long enough service life at amuch lighter load) will necessarily have a high static capacity. But the term „static capacity"is misleading, since the ball screw may actually fail due to fracture of the nut fl ange, nutbody, or connecting bolts before reaching this load!Additional limitations (e.g. buckling) may applyMaximum loads for flange nutaccording to DIN 69051StandardnutUltraThrustnutDIN 69051Nominaldiameter[mm]DIN 69051boltpatternDynamic bolttension Fb*[kN]Static bolt tensionFb*[kN]Bolttorque[Nm]Maximum permissibleaxial load[kN]Maximum permissibleaxial load[ kN ]5/6 4xM3 5 20 1.5 C0 a8 4xM3 5 20 1.5 C0 a10 4xM4 7 28 3 C0 a12 4xM4 7 28 3 716 6xM5 12 40 6 1220 6xM6 16 63 10 1625 6xM6 16 63 10 1632 6xM8 32 100 25 3240 8xM8 40 150 25 4050 8xM10 80 225 49 80 12060/63 8xM10 80 225 49 80 18080 8xM12 125 320 86 125 200100 8xM12 125 320 86 125 200-250100 8xM16 250 630 210 250 250125 8xM16 250 630 210 150¹ 300125 8xM16 250 630 210 250² 350[1] Flange 25 mm thick[2] Flange 30 mm thick* Bolts DIN ISO 4762, Strength 8.8 (90% load, safety factor 0.8, μ = 0.14)Please note: The highest permissible load is the minimum of static capacity C 0a(to prevent brinelling) and fracture load (to preventfailure of ball nut or bolts). Necessary condition for both is proper alignment and squareness of the mounting surfaces and alsoconcentric applied load.TECHNICAL TIPThe structural strength of ball screws for aerospace applications is fi rst predicted using analytical methods including FEM analysis.In some cases, tests are performed in the development phase to demonstrate safety and avoid costly and time consumingredesigns once the qualifi cation phase of the project has started.For the fi nal qualifi cation, tests under exactly the same conditions as in the aircraft must be passed. These tests often require testrigs specifi c to the aircraft program, called „iron bird". The documentation of these tests becomes part of the aircraft qualifi cation.In addition to static tests (limit load, ultimate load), fatigue tests are conducted. In these fatigue tests, an alternating or pulsating loadis applied to a ball screw that is not operating. This is not to be confused with endurance tests, which aim at fatigue also (to confi rmdynamic load capacity), but with the pulsating load generated by balls running repetitively over the same spot of the ball track.33

TechnologyROTATIONAL SPEEDTECHNICAL TIPThe maximum nut speed should not be exceeded under any circumstances. There are, however, special executions available thatare suitable for higher speeds, so please inquire. Critical speed may be exceeded in certain cases - contact our application engineersfor further advice. And critical speed is not a signifi cant limitation in applications with rotating nuts. When operating at prolonged highspeeds, heating of the ball screw may become the limiting factor. Hollow screws for internal cooling are available, but this requiresan expensive additional system with its often troublesome rotating unions. Nuts with cooling jacket, which prevents heat migrationinto the slide, have been tested but are not practical. Another possibile solution to running at high speeds for prolonged time isSteinmeyer‘s technology. This advanced ball screw design produces less than half the heat compared to a regular ball screwof same size. So steady-state temperatures remain much lower. This may eliminate the need to use a forced cooling system for theball screw shaft. Pre-tensioning amounts to compensate for thermal expansion are lower too, signifi cantly reducing the burden on thesupport bearings from tensioning forces.CRITICAL SPEEDCritical speed is the fi rst (lowest) speed at which the ball screw shaft is in resonance. Inapplications with rotating shafts it limits the rpm of the screw. Variables that infl uence itare shaft diameter, unsupported length and support bearing confi guration.Similar to buckling, critical speed depends on the support bearing confi guration. Fixedsupport bearings are assumed to resist angular defl ection of the shaft, while simplesupport bearings do not. A bearing assembly consisting of two simple bearings with aspacer would however qualify as "fi xed" bearing for the purpose here.For long screws, we recommend using the following equation. Make sure to select theproper factor for the bearing confi guration used:n k= k · d N · · 10 7 1l s2n k: Critical Speed [rpm]d N: Nominal diameter [mm]l s: Unsupported length [mm]k: Support bearing factorFixed - fi xed (1): 25.5Fixed - supported (2): 17.7Supported - supported (3): 11.5Fixed - free (4): 3.934

Critical speed [rpm]Length of unsupported shaft Is [mm]TECHNICAL TIPCritical speed is the fi rst resonant frequency (speed) of the rotating shaft. Resonance in a rotating shaft can be catastrophic andeven break the shaft. However, not all ball screws will necessarily exhibit such behavior since the nut represents another supportof the shaft, permanently changing the unsupported length of the shaft and its resonant frequency. Nevertheless Steinmeyerrecommends operating a ball screw only up to a maximum speed not to exceed approximately 80% of the critical speed, or todiscuss the possibility of higher speed with our engineers. For ball screws with rotating nuts, critical speed may be exceeded ifthe run-out of the rotating nut is kept within tight tolerances. A perfectly concentric nut will not „pump" critical amounts of energyinto the shaft even if it is at or near its critical speed.Pre-tensioning and critical speed: Contrary to general belief, pre-tensioning the ball screw shaft does not change the criticalfrequency of the shaft. It is the stiffness against bending that resists centrifugal forces in a rotating shaft, not tension.35

TechnologyROTATIONAL SPEEDMAXIMUM SPEEDA second limitation is imposed by the mass forces upon balls. It depends on internalconstruction of the ball nut and in particular the ball return, and ball diameter (or mass).The D Nvalue does not take lead and ball size into consideration. In general, ball screwswith very small balls have somewhat lower speed limits than screws with larger balls.We strongly recommend observing the speeds in the two tables below instead of D Nvalues.Maximum speeds nominal diameter 3 - 125 mm [rpm]Lead P 3 5 6 8 10 12 16 20 25 28 32 36 40 50 60 63 80 100 1250.5 4500 2900 2900 18001 4500 4500 4500 3000 2000 20001.5 4500 4500 3500 2500 25002 4500 4500 4500 3700 3700 2800 2200 18002.5 4500 4500 4000 4000 3500 4100 25003 4500 4500 4500 4500 4000 4100 30004 4500 4500 4500 4300 4100 3600 2800 28005 4500 4500 4500 4300 4100 3800 3800 3300 3300 2600 2100 1700 1200 1000 8006 4500 4500 4500 4300 4100 3800 3800 3400 3400 3000 2200 1700 1200 1000 8008 4500 4500 4500 4300 4100 3800 3800 3400 3400 3000 2400 1800 1200 1000 80010 4500 4500 4300 4100 3800 3800 3400 3400 3000 2500 2000 1500 1200 100012 4500 4300 4100 3800 3800 3500 3500 3000 2500 2000 1500 1200 100015 4500 4300 4100 3800 3800 3600 3600 3000 2500 2000 1500 1200 100020 4500 4300 4100 4000 4000 4000 4000 3500 3000 2000 1500 1600 100025 4300 4100 4000 4000 4000 4000 4000 3000 2500 2000 2000 1600 120030 4300 4100 4000 4000 4000 4000 3500 3000 2500 2000 2000 1600 120035 3500 3000 2500 2000 2000 1600 120040 3500 3000 2500 2000 2000 1600 1200Maximum speeds forUltraThrust ball screws diameter50 - 125 mm [rpm]Lead P 50 63 80 100 12520 1600 1200 1000 800 65025 1600 1200 1000 800 65030 1600 1200 1000 800 65040 1600 1200 1000 800 65036

TECHNICAL TIPD Nvalues only yield a preliminary idea of the maximum speed, because there are more factors than just the nominal diameterand the type of ball return that affect speed rating. Specifi cally the mass of balls plays an important role, which is not refl ected inD Nratings. Also, the D Nmethod to determine maximum speeds is not applicable for very small screws.D NVALUETECHNICAL TIPWhen using only the D Nmethodto determine maximumrpm for a 3 mm ball screw,the result would be 120.000/ 3 = 40,000 rpm, which iscertainly not realistic. The D Nmethod returns unreasonablyhigh numbers when usedfor very small ball screws!Always check the maximumspeed tables.The concept of D Nis a simplifi ed way of determining the maximum rotational speed ofa ball screw. D Nis simply the multiplication of nominal diameter of the ball screw in mmtimes the maximum allowable speed in rpm. Keep in mind that for very small and verylarge screws this will not return valid numbers.D Nvalues allow easy comparison between different ball screw designs. More sophisticatedball return systems result in higher D Nvalues and, conversely, lower D Nvaluesare associated with less sophisticated ball return methods. D Nvalues provide directcorrelation to ball velocity.D N= n max · d Nn max: Maximum speed [rpm]d N: Nominal diameter [mm]D N: Driving speed value [mm/min]Most ball screws available today have maximum D Nvalues between 60,000 and120,000, and in some cases even higher. However, Steinmeyer recommends observingthe maximum speeds published here for each size. Use the following values fororientation purposes and of course for Steinmeyer ball screws only:Internal return (Series 1xxx): D N≤ 120,000External return (UltraSpeed and end-cap return) (Series 2xxx and 3xxx):D N≤ 160,000High-load ball screws (UltraThrust)(Series 3xxx with ball diameter 15 mm and 19 mm): D N≤ 80,000Always check the maximum speed tables.37

TechnologyBEARING JOURNAL DESIGN AND PRE-TENSIONING BALL SCREWSJournal designASupport bearings facilitate rotation of the shaft while transmitting axial loads from theball screw into the surrounding structure. They have to do that with minimum frictionand the smallest possible deformation under changing loads. Modern ball screwshave high load capacity and rigidity, which places high demands on bearings as well.Only high-end bearings which have been designed specifi cally for use with ball screwscan match the load capacity and rigidity numbers. Using inferior bearings yields unsatisfactoryresults. It is also important that the interface between ball screw and supportbearings is designed properly.A: The simplest journal design is a bearing seat that is small compared to the root diameterof the ball thread. If the shoulder surface between the bearing journal diameterand the root diameter (= nominal diameter - ball diameter) of the ball thread is suffi cientto support the bearing preload plus the maximum thrust with reasonable surface pressure,then this cost-effective solution is recommended.BB: Should the shoulder surface be too small, then the shaft could actually bend whenthe locknut is tightened to preload the bearings. In this case, a full shoulder is needed,that is the ball thread has to be incomplete instead of cutting through the shoulder -sometimes referred to as a „dead start thread". This is possible for ground and whirledscrews, but impossible for rolled screws. Make sure that the other end of the ball threadis complete to allow mounting of the nut. Two incomplete ends of the ball threadmeans costly complications of nut mounting!CC: If the shoulder surface is still insuffi cient, then a collar becomes necessary. Collarscan be heat shrunk onto the ball screw if there is still some difference between bearingbore diameter and screw O.D. Shrunk collars are also possible for rolled screws. Ifthere is not enough shoulder for the shrunk collar to prevent axial slippage, then thecollar has to be solid, which means considerable machining time. This is the mostexpensive solution.TECHNICAL TIPIf a long screw is to be pre-tensioned to compensate for thermal expansion, thrust bearings are required at both ends. One ofthem needs to be adjustable to set exact tension of the shaft. A way to do that is by using a second locknut thread. Other possibilitiesinclude shims to set pre-tension. Always make sure to check elongation of the screw with a dial gage while tensioning it.Suffi cient shoulder area is important, since creeping of the metal and loss of bearing preload results from excessive surfaceloading. If the shoulder surface is not symmetric (for example when the thread cuts through it and the shoulder surface belowthe root is insuffi cient to support the bearing), then cocking of the bearing will cause bending of the shaft with unsatisfactoryrunout of the ball screw.38

PRE-TENSIONING A BALL SCREWThe purpose to pre-tension a ball screw is to compensate for thermal expansion duringoperation and thus avoid compressive forces as the shaft expands between thetwo fi xed bearings. The goal is to stretch the screw suffi ciently to maintain at leastsome tension at the highest anticipated temperature. TECHNICAL TIP There is only a minimal change in the resonant frequency (critical speed) of theshaft when tensioned. But tensioning is necessary when the screw is supportedby fi xed bearings at both ends. The fi xed bearings do of course result in raisingcritical speed.Ball screws may be ordered with a negative lead compensation c, so that aftertensioning the lead deviation is near zero.Anticipating the temperature∆l T= l s · ∆t · αSteinmeyer is capable of determining the steady-state temperature for your duty cycle.Please contact us for details.Δt :α :l s:Temperature rise [°C]Coeff. of thermal expansion [1/°C](for DIN 1.1213 = 11.5 x 10 -6 /°C)Shaft length [mm]Calculating the elongationThe elongation of the shaft should at least be equal to the thermal expansion for theanticipated steady-state temperature, or slightly larger.∆l p≥ ∆l TΔl p:Δl T:Amount of elongation [mm]Thermal expansion [mm]Calculating the tensioning forceF T= E · A · εε =∆l pl sF T: Tensioning Force [N]E: Elasticity modulus [N/mm 2 ]A: Shaft cross section [mm 2 ]ε: Elongation relative to lengthPre-tensioning requires considerable forces. In applications with rotating shaft, thesupport bearings have to withstand these forces, which becomes a main considerationfor the selection of the bearings.To calculate the tensioning force, assume that the root diameter of the screw is approximatelythe nominal diameter minus the ball diameter.39

TechnologyBEARING JOURNAL DESIGNSELECTING SUPPORT BEARINGSTECHNICAL TIPMiniature ball screws arenormally supported usingeither a pair of angularcontact bearings on oneend, or by a single-rowbearing at both ends of thescrew, preloaded againstone another. It is better touse bearings with increasedplay here, since this will establisha more desirable contactangle when the bearingsare preloaded. Bearings withminimal or no play may generateexcessive forces ontheir balls when preloadedthis way, causing potentialpremature bearing failureand rough motion.Support bearings must be able to carry not only the thrust produced by the ball screw,but also any additional forces from pre-tensioning the ball screw shaft, plus any side forcesgenerated by belt drives. Ball nuts with many ball circles and/or large balls and shafts withconsiderable pre-tension may make it diffi cult to fi nd bearings with suffi cient load capacity,especially when the bore (ID) of the bearing has to be no larger than the shaft‘s root diameter,and the journal shoulder diameter no larger than the ball screw‘s nominal diameter.This discussion is only meant to highlight areas of concern. We cannot give detailedrecommendations on which bearing to select. Criteria for the selection include:Axial dynamic load capacity of the bearing should be approximately equal to thedynamic load capacity of the ball screw, or higher if the screw is pre-tensioned.Minimum shoulder diameter for the bearing‘s inner ring should be no greater thanthe root diameter of the ball screw (journal shape A), or no greater than the screw‘snominal diameter (journal shape B).The bearing should be suitable for the same lubrication method (grease/oil) andequipped with the proper seals for that lubricant. Speed ratings must be suffi cientwith the lubricant selected.Steinmeyer recommends using INA support bearings. The following table gives examplesof typical ballscrew / bearing assemblies. However, it is not possible to coverall combinations in this catalog. Please refer to our engineering service for furtherinformation.BallscrewnominalINA-bearing with journal configuration acc. to fig.diameter d N[mm]A B C16 ZKLN1034 - ZKLN124220 ZKLN1242 - ZKLN154525 ZKLN1747 - ZKLN205232 (P≤5) ZKLN2557 - -32 (P>5) ZKLN2052 ZKLN2557 -40 (P≤5) ZKLN3062 - -40 (P>5) - ZARN3062LTN -50 (P≤5) ZKLN4075 - -50 (P>5) - ZARN4075LTN -63 (P≤5) ZKLN5090 - -63 (P>5) ZARN4090LTN ZARN45105LTN -80 - ZARN50110LTN -100 - ZARN60120LTN -This brief overview cannot give a fi nal selection aid to determinate an optimum bearingsolution. Radial loads due to drive belt tension or increased axial loads due to pretensioninga ballscrew need to be considered, too.40

LUBRICATION AND WIPERS / SEALSSupply of fresh lubricant and wipers must be considered together. The selection notonly depends on environmental conditions, but also on loads and speeds. In this sectionwe discuss whether grease or oil is the right lubricant, and which grease or oilshould be used.Plastic WiperPlastic wipers, sometimes called „labyrinth seals", are widely used in machine applications.They prevent contamination of the nut from chips and other larger particles,while at the same time letting some oil exit the nut. Combined with automatic grease oroil lubrication, they help to fl ush the nut. The result is higher reliability of the ball screw.Felt WiperFelt wipers are an excellent solution for ball screws operated in an environment withabrasive or otherwise troublesome dirt as in grinding or woodworking machines (forexample oil absorbing particles like wood chips). The felt wiper seals the nut effectively,even from fi ne particles, and also stores some lubricant. Felt wipers are contact wipersand add some friction.Combination WiperCombination wipers are plastic wipers with an additional felt wiper (inside the ball nut).They are used where felt wipers are desirable, but need to be protected from water orwater based fl uids. Felt tends to absorb water, so it should not be used without theadditional plastic wiper in such cases.Combination wipers add to the nut length - please consult Steinmeyer for details.TECHNICAL TIPIf the duty cycle is such that an EHD lubrication fi lm can build over a signifi cant part of the motion, then oil lubrication with aproperly selected oil grade and viscosity will always outperform grease in terms of wear. On the other hand, grease has an edgeat slow speeds because it offers better wear protection under mixed friction or boundary friction conditions. Grease can also beused for long-term or for-life lubrication. Lubricant loss with grease is lower than with oil.A general discussion for oil vs. grease lubrication and the results of a scientifi c test of several commonly used lubricants by thetribology lab of CSEM at Neuchâtel/Switzerland (www.csem.ch ) is shown on the next pages.41

TechnologyCOMPARATIVE TEST OF LUBRICANTS PERFORMED AT CSEM / NEUCHÂTELTRIBILOGY OIL / GREASEOn behalf of Steinmeyer and under the scope of a EUREKA project sponsored by the KTI(Commission for Technological Interchange) in Switzerland, the tribology lab of CSEM(Centre Suisse d‘Electronique et Microtechnique) designed and conducted a test forcommonly used lubricants under the specifi c tribological conditions found in ball screws.A modifi ed pin-on-disc tribometer was used, with the pin replaced by a regular bearingball made from 52100 steel, which rode on a rotating disc made from the same material,heat treated and ground similar to the raceway of a ball screw.The disc and the ball closely resembled the friction partners in a ball nut in terms ofmaterial and surface fi nish.Surface loads and relative speeds in two test series were selected to simulate a slowmoving ball screw and a fast moving one. Since the pin-on-disc tribometer causes puresliding instead of the sliding/rolling typical for a ball screw, the speeds were adjusted tothe sliding portion of typical mid-size ball screw kinematics, running at about 50 rpm(0,04 cm/s in the tribometer) and at approximately 1000 rpm (32 cm/s in the tribometer).This simulated as closely as possible the real tribological conditions in a ball screw, bothin terms of lubrication fi lm build-up, and wear.Results:First of all, the coeffi cient of friction does not seem to be correlated to the wear rate.Some lubricants yielded low friction, but higher wear at the same time!The wear rates of some greases show that these lubricants can really be seen as„universal", because they offer moderate wear protection at both slow and fastspeeds.At the higher speed, both oils built a hydrodynamic lube fi lm, which can be concludedfrom the extremely low wear rates.A plain mineral oil without wear-inhibiting additive (Vactra4) yielded excessive wearrate at slow speed, despite its high viscosity. It was obviously unable to protect thefriction partners once speed fell below the threshold to build a hydrodynamic fi lm.It was squeezed out of the contact patch and did not suffi ciently reduce wear inboundary conditions.Oil with high-pressure, wear inhibiting additives (EP oil), which is able to bond itshydrocarbon molecules to metal surfaces through chemical or physical reaction,performs much better during conditions of boundary friction.With the exception of a high-pressure grease, which caused the lube fi lm to collapse athigh speeds, all greases performed well and yielded acceptable wear rates throughoutthe test scenario. At the same time it was proven that greases are unable to build aperfect fl uid fi lm like oils of proper viscosity, so the wear rate with grease lubrication ishigher than the wear rate of oil when an EHD fi lm is present.42

LUBRICATION AND WIPERS / SEALSTheory of elasto-hydrodynamic (EHD)lubricationLife calculations for ball screws assume suffi cient lubrication, which means that thereis an adequate lubrication fi lm. In case of oil lubrication this means that whenever thespeed is suffi cient, a fl uid fi lm develops which separates the contact partners as muchas possible. This requires thatsuffi cient oil is available at all timescontamination is minimallubricant is in adequate conditionviscosity is selected so that over most of the duty cycle a hydrodynamic lube fi lm ismaintainedThe necessary condition to form such a fl uid fi lm is described by the theory of elastohydrodynamiclubrication. Whether a fl uid fi lm, able to withstand the pressure in thefriction contact zone, will build depends on the actual viscosity of the lubricant andthe speed and, to a lesser extent, the pressure. However, a certain minimum load isrequired (for example by preloading the ball screw) to cause a consistent rolling motionof the balls.Whether an EHD fi lm will build can be determined from the viscosity ratio k = u / u 1 .The operational viscosity u is the viscosity the lubricant exhibits under the conditions inthe contact patch in terms of speed, temperature and pressure. The viscosity neededto build a suffi cient EHD fi lm is u 1 .The viscosity ratio can be classifi ed in 3 parts.k ≥ 4 full EHD lubrication - contact partners are mostly separated0.4 ≤ k < 4 mixed friction - lubricant with wear inhibiting additives is necessary, sinceEHD fi lm is only partially able to separate contact partners (EP - grease, CLP - oil)k < 0.4 no separation - accelerated wear through micro welding will occurSince a high viscosity ratio is desirable, oil with high viscosity seems to be the solution.But high oil viscosity also causes high temperatures, which in turn could lower theactual viscosity again. High viscosity oil is also diffi cult to deliver to all lubrication pointsand will not aid in cooling the ball nut.We recommend using oil viscosities as close as possible to the ones per the followingtable.43

TechnologyOIL LUBRICATIONOil lubrication requires an oil port in the nut and wipers. Steinmeyer ships all ball screwslubricated ready for use. If the screw is to be used with oil lubrication, please notifyus when ordering - we will then pack the nut with a special grease, which requires nocleaning prior to use. The grease will be washed away with time and be dissolved inthe oil. The grease fi ll protects the screw during shipping and storage, and keeps itlubricated until the oil supply is operational.Oil should be injected approximately four times per hour. Recirculating oil systemsshould include a fi lter with a 10 micron mesh and a cooler to keep the oil temperaturebelow 50° C as it enters the ball nut. Oil mist is only recommended when there are nowipers and contamination is very low. Oil bath lubrication can only be used for very lowspeeds. Oil drip and loss lubrication is possible, but oil quantities must be observed.Recommended oil quantitiesNominaldiameter [mm]Oil quantity in cm 3 /hr foroil circulationwithout extracoolingwith extracoolingOil quantity inmm 3 /min for minimumquantity lubrication(MQL) or oilmist lubrication16 0.12 0.3 120 0.15 0.4 1.525 0.2 0.5 232 0.25 0.7 2.540 0.3 0.9 350 0.4 1.5 463 0.5 2 5.080 0.6 3.0 6.0100 0.8 4.0 8.0125 1.0 5.0 10.0Suitable oil gradesOnly oils with wear inhibiting additives should be used. These have the ability to lubricatein conditions of boundary friction, when speeds for EHD-lubrication are insuffi cient.We strongly recommend CLP grade gear oil per DIN 51517-3 or equivalent. Donot use way oils or hydraulic oils, even if they are labeled „high pressure"!44

Recommended oil viscosity for EHDlubricationNominaldiameter[mm]Meanspeed[rpmViscosityu1[mm 2 /s]Lubricanttemperature[°C]Viscositygrade ISOVGActualviscosity u[mm 2 /s]up to 16 10 ca. 3000 30 680 ca. 300050 500 35 320 500200 180 40 220 220500 70 45 100 801000 40 50 68 422000 28 55 68 3520 to 32 10 ca. 1200 30 460 ca. 120050 350 35 320 500200 120 40 150 150500 50 45 68 501.000 30 50 46 30over 40 10 ca. 900 30 320 ca. 90050 250 35 220 300200 80 40 100 100500 35 45 46 35TECHNICAL TIPFelt or combination wipers seal the nut. It is therefore important, when using such wipers, that the recommended oil fl ow ratesare not exceeded. The nut may become overfi lled causing overheating at higher speeds.Service life of oil lubricated ball screws exceeds the life that can be expected with grease lubrication in many cases, but only ifEHD lubrication can be reached over most of the duty cycle.45

TechnologyGREASE LUBRICATIONRe-lubrication of ball screws should be done with grease having the same, or compatible,thickener as the grease used for factory lubrication. The base oil viscosity shouldalso be approximately the same. If not specifi ed otherwise, Steinmeyer uses KluberStaburags NBU 8 EP for factory grease fi ll of the nut. Please note that the factorygrease fi ll is only enough for initial operation, until the fi rst required re-lubrication.Manual re-lubricationBall screws with regular plastic wipers should be re-greased every 500 hours of continuousoperation, or four times a year. Ball screws with felt wipers have a recommendedre-greasing interval of 1000 hours of operation, or twice a year.If the ball screw is fi tted with felt or combination wipers and is adequately protectedfrom dirt and liquids (e.g. water, coolant), then the re-lubrication interval may be extendedto 2000 hours or once a year. In such cases, Steinmeyer will pack the ball nutwith long-term grease Kluber Isofl ex NBU 15, and impregnate the felt wiper with an oilcompatible with this grease. Please consult with our application engineers if you wantyour ball screw prepared for long-term lubrication.Automatic grease lubricationThere are two possible ways to automatically re-lubricate ball screws. Either the nut isconnected to an automatic lubrication pump with multiple ports, or a lubrication cartridgeis used. Both require a grease which is not too viscous and can be reliably pumpedthrough piping to its destination. Grease cartridges powered by chemical gas generatorskeep the grease pressurized all the time, which can cause the base oil to separatefrom the thickener resulting in clogged lines and lubrication breakdown. We recommendelectromechanical cartridges, which use a gear motor and a lead screw to pump thelubricant. These do not keep the grease under continuous pressure, thus preventingsuch problems.Normally, liquid greases NLGI class 0 or 00 are used for automatic grease lubrication,because they can be pumped through long lines more easily. With large enough pipediameters, grease class 1 or even 2 can be used as well - but should fi rst be tested.The intervals and quantities are shown on page 47.TECHNICAL TIPMineral oil based lubricants degrade with time in two ways:They are attacked by aggressive chemicals (for example oxygen) from their environment, which causes a polymerization of the hydrocarbonor oxidation. The lubricant turns into a solid with time, but the process is slow in a normal environment, so re-lubricationin normal intervals replaces the lubricant before it becomes too degraded. However, this chemical aging limits the storage period ofpre-greased components to 2 - 5 years. Specifi cs can be obtained from grease manufacturers.During use, the hydrocarbon molecules are subjected to mechanical stresses when they are passed through the contact patches.This mechanical stress causes the molecule chains to break up over time, reducing the viscosity. The maximum usage time of thelubricant can be calculated - please contact us.46

TechnologyRecommended GreaseApplication Kluber Lowtemp.limit [C°]Generalpurpose,long-termgrease forhigh surfacepressureLong-termgrease withfelt wipersStaburagsNBU 8 EPIsoflex NBU15Uppertemp. limit[C°]Base oilviscosity[mm 2 /s]at 40°CLubcon-20 140 100 TurmogreasePHS 1002-30 130 23 TurmogreaseHighspeedL252Lowtemp.limit[°C]Uppertemp.limit[°C]Base oilviscosity[mm 2 /s]at 40°C-40 160 105-50 120 25Long-termgrease withoutfelt wipers, lowspeeds onlyLowfrictiongreaseHightemperaturegreaseStaburagsNBU12/300KPIsoflex LDS18 Spezial AKlüberalphaBHR 53-402-20 140 220 TurmogreaseCAK 4002-50 120 15 Thermoplex 2TML Spezial-40 260 400 TurmotempSuper 2 EP-20 150 400-70 130 20-30 280 500LowtemperaturegreaseIsoflex PDL300 A-70 110 9 ThermoplexTTF 122-70 150 12Vacuumgrease,clean roomBarriertaL55/2-40 260 400 TurmotempII/400 KLTurmotempII/400 RS2-30-30260260400550Food gradegreaseKlübersynthUH1 14-151-45 120 150 TurmosynthgreaseALN2501-40 160 250Hybrid ball screwsHybrid design of ball screw means screw and nut are made from steel and balls aremade from ceramic.Most suitable ceramic is Silicon Nitride in HIP-quality (not isostatic pressed).Hybrid ball screws are designed to operate with very minimal lubrication. When adequatelubrication is available there is no difference compared to conventional ballscrews equipped with steel balls.The high hardness and Young´s modulus of Silicon Nitride (Si 3N 4) results in a higherapplied load to the steel-ball race. Hybrid ball screws however must be assembledusing smaller steel spacer balls which means that only 50% of the balls are carryingload. Therefore, the application of hybrid ball screws must be carefully reviewed.48

BALL RETURNTECHNICAL TIPBall nuts require a means to recirculate balls. Without it, the ball path would not be closed and balls would fall out at the rear endof the nut. Design of the ball return is the determining factor for the maximum speed at which the ball nut can safely operate.This is normally expressed by the D N-value. The better the ball return system deals with mass forces of the balls, the higher theD Nvalue. Manufacturers typically quote D Nvalues from 60.000 for basic tube returns to 160.000 and higher, e.g. the UltraSpeedreturn from Steinmeyer.Steinmeyer uses all commonly known designs for ball returns. However, the multi-liner and the tube return are only used foraerospace „build-to-print" applications, since staying with a previously qualifi ed design simplifi es the qualifi cation procedure.Track-to-track(internal return)The track-to-track return uses ball defl ectors to lift the balls across the O.D. of theshaft and guide them directly into the next (or previous) track. Internal ball return is verycompact and yields the smallest nut diameters among all ball return systems. It is alsothe ball return of choice for very small ball sizes and small leads.Each defl ector serves one turn, which is one circuit (or ball circle).Through-the-nut return(external return)Steinmeyer‘s „UltraSpeed" return is normally used for lead/diameter ratios greater than0.5. It is normally used with dual start threads. Balls are lifted off the shaft using adefl ector at one end of the nut and then guided through a bore (internal to the nutbody) to the other end of the nut, where a similar piece guides the balls back onto thethread. One pair of defl ectors serves one circuit (i.e. one of the threads) which includesseveral turns.End cap returnEnd cap return works very much like the previously described through-the-nut return,with the exception that the ball defl ector function is executed using a (plastic) cap atboth ends of the ball nut. Each cap serves as the ball return and also includes wipers.End cap return is normallly used for very large lead/diameter ratios. This style ball nutis only available as a fl ange nut.49

TechnologyMATERIALS AND PROCESSESMaterialsApplicationMaterialNo.AMSdesignationDIN / ISOdesignationANSIdesignationAerospacegradeShaft 1.12131.20671.40211.41121.41081.41231.4125AMS 5351AMS 7445DAMS 5898AMS 5925AMS 5618AMS 5844Cf53100Cr6X20Cr13X90CrMoV18X30CrMoN15-1XD15WX105CrMo17105052100440 B440 CMP35N••••Generalpurpose1.45451.4548AMS 5659AMS 5643X5CrNiCuNb17-4-415-5 PH17-4 PH••Nuts 1.20671.4108 AMS 5898100Cr6X30CrMoN15-1•Balls 1.20671.41081.4125AMS 5898AMS 5618102Cr6X30CrMoN15-1X105CrMo17440 C••SAEdesignationProcessesAS 7003 /NADCAPcertifiedCertifiedthrough 3rdparty/customerauditExternalprocessAS 7102 Heat treatment • • •AS 7114 Induction hardening • •AS 7108 Chemical processes • •AS 1701 NDT • •AS 7117 Surface treatment • •AS 7115 Elastomer Seals/• • •GasketsAS 7200 Sealants • • •AS 7101 Non-standard treatment • • •50

DEFINITIONSA: Shaft cross section [mm 2 ]α: Coeffi cient of thermal expansion [1/°C]c: Lead compensationC 0a: Static axial load capacity [N]C a: Dynamic axial load capacity [N]C aerf.: Required dynamic axial load capacity [N]Δl b/t: Axial elastic deformation dueto external load F i[μm]Δl b/t,pr: Axial elastic deformation due to preload F pr[μm]Δl p: Elongation of the shaft [mm]Δl T: Thermal expansion [mm]d N: Nominal diameter [mm]D N: Driving speed value [mm/min]Δt: Temperature increase [°C]„E": Tolerance of the cumulative lead error (JIS)E: Elasticity modulus [N/mm2]ε: Elongation relative to lengthe 0a: Mean lead deviation over entire travel l ue 2π: Lead error in one revolution (JIS)e 300: Lead error in 300 mm (JIS)e p: Tolerance for the average lead deviationover entire travel l ue sa: Actual lead deviation over entire travel l uF i: External load [N]F i*: Modified external load [N]F m: Dynamic equivalent load [N]F m*: Modified dynamic equivalent load [N]F pr: Preload [N]F T: Tensioning force [N]i: Number of ball circlesJIS: Japanese Industrial Standardk: Support coeffi cient (critical speed)L 10: Nominal life 90% reliability [revolutions]l s: Unsupported shaft length [mm]l u: Travel [mm]m: Support coeffi cient (buckling]n i: Speed [rpm]n k: Critical speed [rpm]n m: Equivalent Speed [rpm]n max: Maximum Speed [rpm]P: Lead [mm]P B: Buckling load [N]P i: Load capacity per ANSI [lbf]q i: Time percentage [%]R b: Axial bearing rigidity [N/μm]R nu,ar: Actual nut rigidity [N/μm]R s: Shaft rigidity [N/μm]R t: Rigidity of ball screw [N/μm]T: Travel compensation (JIS)T pr: Preload torquev 2πa: Lead fl uctuation in one revolutionv 300a: Lead fl uctuation in 300 mmv 300p: Tolerance of the lead fluctuation in 300 mmv ua: Lead deviation over entire travel luv up: Tolerance of the lead deviationover entire travel l u51

TechnologyNUMBERING SYSTEMBALL SCREWS1 4 1 6 / 5 .40. 800 . 900 L P 3 P1 nut with internal return2 nut with end cap return3 nut with external return1 single nut with connection thread2 cylindrical single nut3 cylindrical double nut4 flange single nut5 flange double nut1 single start thread, ground2 dual start thread, ground3 single start thread, rolled4 dual start thread, rolled5 single start thread, whirled0 spring preloaded double nut2 standard nut (Ø 3-16 mm)4 customized nut6 nut according to DIN 69051lead (mm)nominal diameter (mm)thread length (mm)overall length (mm)EL lefthand threadR stainless steelP positioning ball screwT transport ball screwtolerance classP preloaded nutNote:This item number describes a ball screw with fl ange single nut acc. to DIN with internalreturn. Single start thread, ground. Lead 5 mm, nominal diameter 40 mm,thread length = 800 mm, overall length = 900 mm, left hand thread, tolerance class P3,preloaded nut.52

Welcome to where precision is.Large Ball ScrewsDiameter 16 - 125 mm106

LARGE BALL SCREWS DIAMETER 16 - 125 MM, GROUND THREADThis section includes nuts with standard dimensions per ISO 3408 / DIN 69051. In most cases, there is a choice of three differentfl ange shapes (full round, single fl at, or double fl at) and different number of ball circles and load capacities.The majority of these nuts is available either in single nut execution with 4-point contact, double nut execution with 2-point contact,or advanced execution, which you see on the double nut pages. Technical data for ball screws are shown in parenthesis.Some sizes are no longer available as conventional double nuts. In such cases, the page shows only data for ball screwsSteinmeyer produces ball screws for machine tool and similar use with custom shafts only. For a quote, we just need a drawing orsketch that suffi ciently defi nes the shaft.The nut can be a standard one shown on the following pages, or custom. Even for the custom version, you may obtain useful informationfrom the listing of technical data, since load capacities, rigidity or friction torque will be the same as in the correspondingstandard version. Of course we are also prepared to assist you in selecting a nut that best meets your needs, recommend the rightpreload setting or provide minimum nut dimensions to yield a given life expectancy of the unit.TECHNICAL TIPSteinmeyer ball screws with nominal diameters of 16 mm to 125 mm are available as screws, which yields a clear performanceadvantage for your linear drive. technology signifi cantly reduces friction while, at the same time, the rigidity increases.Life is also improved. ball screws have near zero reversing error and may be used with much higher servo loop gain.The nuts of ball screws are often somewhat shorter than the double nuts shown on the following pages, but for simplicitythe difference is not shown. Please inquire if a small reduction in overall nut length is desired.ball screws may be found on the following pages. Technical data are given in parenthesis. When inquiring, please clearlystate that you want execution.Due to the success of , some sizes are no longer available in conventional execution.is a registered trademark of August Steinmeyer GmbH & Co. KG.107

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 16 – 20 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 2426:End cap nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 2.16.1,5.32.16.1,5.44.16.3.34.16.3.45.16.3,5.35.16.3,5.42244551616161616163434341.51.53.03.03.53.52.93.88.911.410.112.94.96.511.415.212.016.02002601702201502002426 10.16.3,5.610.16.3,5.810.16.3,5.101010101616163 + 34 + 45 + 53.53.53.519.625.631.427.437.747.82703604501416 2.20.1,5.22.20.1,5.32.20.1,5.42.20.1,5.54.20.3.24.20.3.34.20.3.45.20.3,5.25.20.3,5.35.20.3,5.410.20.3,5.210.20.3,5.3222244455510102020202020202020202020202345234234232426 10.20.3,5.10 10 20 5 + 5 3.5 36.4 63.0 63020.20.3,5.420.20.3,5.620202020* Actual stiffness at preload equal to 0.08 x C a2 + 23 + 31.51.51.51.53.03.03.03.53.53.53.53.53.53.52.33.24.15.07.110.113.08.612.115.58.512.014.721.74.16.28.210.39.914.919.911.216.722.311.116.622.435.2130190250310150220290140210270110160140220108

AView “A”PDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 3943495354592828282828281010101010103838383838385.55.55.55.55.55.54848484848481010101010106666662020202020200000009999992426 4959693232321616164242425.55.55.5525252101010777202020000---1416 4348525643495348556062763636363636363636363636361610101010101010101016164747474747474747474747476.66.66.66.66.66.66.66.66.66.66.66.62426 69 36 16 47 6.6 58 10 7 22 0 -57773636161647476.66.6585858585858585858585858LA *: Additional nut length at each end when using combination wipers585810101010101010101010101010106666666666777722222222222222222222222222220000000000000099999999991212--109

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 25 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 2426:End cap nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 2.25.1,5.32.25.1,5.42.25.1,5.54.25.3.34.25.3.45.25.3,5.35.25.3,5.45.25.3,5.510.25.3,5.210.25.3,5.32224455510102525252525252525252534534345231.51.51.53.03.03.53.53.53.53.53.54.55.511.414.613.717.521.29.613.67.810.413.019.325.721.528.735.914.321.412.28.4.4 12 28 4 4.0 22.1 37.2 3102426 10.25.3,5.10 10 25 5 + 5 3.5 40.3 78.4 83015.25.3,5.415.25.3,5.620.25.3,5.420.25.3,5.615152020252525252 + 23 + 32 + 23 + 33.53.53.53.516.824.917.125.228.645.029.546.425.25.3,5.4 25 25 2 + 2 3.5 16.7 29.0 180* Actual stiffness at preload equal to 0.08 x C a220290370270360260350430150220270410230340110

AView “A”PDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 435156495355606664784040404040404040404010101010101010101616515151515151515151516.66.66.66.66.66.66.66.66.66.66262626262626262626298 40 16 51 6.6 62 10 7 24 0 122426 69 40 16 51 6.6 62 10 7 24 0 12486357774040404016161616515151516.66.66.66.66262626266 40 16 51 6.6 62 10 7 24 0 12LA *: Additional nut length at each end when using combination wipers10101010101010101010101010106666666677777724242424242424242424242424240000000000000099999999121212121212111

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 32 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 3426:UltraSpeed nut with fl ange, dual start,ball oversize preload■ Series 3416:UltraSpeed nut with fl ange, single start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 4.32.3.34.32.3.45.32.3,5.35.32.3,5.45.32.3,5.55.32.3,5.66.32.4.36.32.4.48.32.5.48.32.5.610.32.6.310.32.6.410.32.6.544555566881010103232323232323232323232323234345634463453.03.03.53.53.53.54.04.05.05.06.06.06.013.116.816.020.424.829.018.724.031.544.630.839.447.826.335.029.839.849.759.032.743.752.078.045.660.876.012.32.5.3 12 32 3 5.0 24.5 38.8 2803416 15.32.6.315.32.6.53426 20.32.6.420.32.6.620.32.6.815152020203232323232352 + 23 + 34 + 46.06.06.06.06.028.547.339.357.975.643.177.763.6100.0136.425.32.6.4 25 32 2 + 2 6.0 38.7 63.0 30030.32.6.4 30 32 2 + 2 6.0 38.1 62.2 250* Actual stiffness at preload equal to 0.08 x C a350460350460570680340450420620300400490270450360530710112

AView “A”PDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 51555762677361688410284951073416 741043426 688810850505050505050505050505050101010101010101016161616166565656565656565656565656599999999999998080808080808080808080808012121212121212121212121212666666667777731.031.031.031.031.031.031.031.031.031.031.031.031.094 50 16 65 9 80 12 7 31.0 0 1256565656562020202020717171717199999868686868614141414147777732.532.532.532.532.578 56 20 71 9 86 14 7 32.5 5 2288 56 20 71 9 86 14 7 32.5 5 22LA *: Additional nut length at each end when using combination wipers0000000000000000009999999912121212121212121212113

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 40 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 3416:UltraSpeed nut with fl ange, single start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 5.40.3,5.35.40.3,5.45.40.3,5.55.40.3,5.655554040404034563.53.53.53.517.722.727.532.138.250.963.676.44305707008406.40.4.46.40.4.68.40.5.48.40.5.666884040404046464.04.05.05.026.737.935.850.756.184.268.2102.356082054080010.40.7,5.310.40.7,5.410.40.7,5.51010104040403457.57.57.546.159.071.571.395.1118.93905206503416 10.40.7,5.3 N10.40.7,5.4 N10.40.7,5.5 N10.40.7,5.6 N1416 12.40.7,5.3 N12.40.7,5.4 N15.40.7,5.315.40.7,5.43416 15.40.7,5.3 N15.40.7,5.4 N15.40.7,5.5 N15.40.7,5.6 N1010101012121515151515154040404040404040404040403456343434561416 16.40.7,5.5 16 40 5 7.5 71.1 118.3 55020.40.7,5.220.40.7,5.320204040237.57.57.57.57.57.57.57.57.57.57.57.57.57.543.157.571.484.946.058.945.958.742.957.271.184.432.145.567.995.1122.3149.571.295.071.194.867.794.8121.8148.947.170.7420560700840380500350460370490620740200300114* Actual stiffness at preload equal to 0.08 x C aN: Alternate sizes acc. to DIN 69051

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 59646975636363631010101078787878999993939393141414146666353535350000999970838610463636363101016167878787899999393939314141414667735353535000099121286971106363631616167878789999393931414147773535350001212123416 85951051151416 921051041213416 981131281437070707070706363707070702525252525251616252525258585858585857878858585859999999999991416 144 63 16 78 9 93 14 7 35 0 1292121636316161001001001001001009393100100100100LA *: Additional nut length at each end when using combination wipers787899939314141414141414141414141414147777777777777737.537.537.537.537.537.5353537.537.537.537.53535000000000000001212121212121212121212121212115

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 40 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 3426:UltraSpeed nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]3426 20.40.6.620.40.6.820.40.7,5.6 N20.40.7,5.8 N20202020404040403 + 34 + 43 + 34 + 46.06.07.57.564.984.783.8109.5126.3172.2148.1201.973096071094025.40.6.625.40.6.825.40.7,5.6 N25.40.7,5.8 N25252525404040403 + 34 + 43 + 34 + 46.06.07.57.564.384.086.5113.0125.4171.0156.3213.163084065087030.40.6.630.40.6.830.40.7,5.6 N30.40.7,5.8 N30303030404040403 + 34 + 43 + 34 + 46.06.07.57.563.683.185.6111.8124.4169.6155.0211.355073057075040.40.6.640.40.7,5.4 N404040403 + 32 + 26.07.561.956.5121.996.6410280* Actual stiffness at preload equal to 0.08 x C aN: Alternate sizes acc. to DIN 69051116

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]3426 891099011063637070202025257878858599999393100100141414147777353537.537.500001212121210713210412963637070161625257878858599999393100100141414147777353537.537.555552222222212115112315363637070161625257878858599999393100100141414147777353537.537.555552222222214810763701625788599931001414773537.5552222LA *: Additional nut length at each end when using combination wipers117

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 50 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 3426:UltraSpeed nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 5.50.3,5.35.50.3,5.45.50.3,5.55.50.3,5.655555050505034563.53.53.53.519.625.130.435.648.965.281.597.8520680850101010.50.7,5.310.50.7,5.410.50.7,5.51010105050503457.57.57.552.767.481.793.2124.3155.451067083015.50.7,5.315.50.7,5.415.50.7,5.51515155050503457.57.57.552.567.281.493.0124.0155.047061076015.50.9.3N15.50.9.4N15.50.9.5N1515155050503459.09.09.077.298.8119.7130.4173.9217.452069085020.50.9.320.50.9.420.50.9.3 N20.50.9.4 N3426 20.50.7,5.6 N20.50.7,5.8 N20202020202050505050505034343 + 34 + 49.09.09.09.07.57.576.898.476.898.497.5127.3130.0173.3130.0173.3198.2270.325.50.7,5.8 N 25 50 4 + 4 7.5 126.6 269.1 118030.50.6.830.50.7,5.8 N35.50.7,5.6 N35.50.7,5.8 N30303535505050504 + 44 + 43 + 34 + 46.07.57.57.592.6125.795.5124.7214.6267.6195.0265.940.50.7,5.6 N 40 50 3 + 3 7.5 94.6 193.6 640470620470620980130010301060720950118* Actual stiffness at preload equal to 0.08 x C aN: Alternate sizes acc. to DIN 69051

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 616671767575757510101010939393931111111111011011011016161616666642.542.542.542.500009999889911175757516161693939311111111011011016161677742.542.542.500012121210712414275757516161693939311111111011011016161677742.542.542.500012121211212914782828225252510010010011111111811811816161677746.046.046.00001212121291501291503426 911117575828282821616252525259393100100100100111111111111110110118118118118130 82 25 100 11 118 16 7 46.0 5 2215215013517075828282162525259310010010011111111110118118118149 82 25 100 11 118 16 7 46.0 5 22LA *: Additional nut length at each end when using combination wipers16161616161616161616777777777742.542.546.046.046.046.042.546.046.046.0000000555512121212121222222222119

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 60 – 63 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 3426:UltraSpeed nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]3426 25.60.9.625.60.9.830.60.9.630.60.9.825253030606060603 + 34 + 43 + 34 + 49.09.09.09.0164.3214.5163.5213.5361.5492.9360.1491.035.60.9.6 35 60 3 + 3 9.0 162.5 358.5 114040.60.9.440.60.9.6404060602 + 23 + 39.09.0109.5161.5227.0356.720.63.7,5.8 20 63 4 + 4 7.5 140.5 339.7 16601416 5.63.3,5.45.63.3,5.55.63.3,5.65556363634563.53.53.527.833.739.584.3105.4126.5135017901250165070010408201010120010.63.7,5.310.63.7,5.410.63.7,5.510.63.7,5.6101010106363636334567.57.57.57.559.275.891.8107.4120.7160.9201.1241.36308301030123015.63.9.4 15 63 4 9.0 116.7 239.9 94020.63.11.320.63.11.420.63.11.520202063636334511.011.011.0115.3147.7179.0209.1278.8348.530.63.11.3 30 63 3 11.0 114.4 207.8 550* Actual stiffness at preload equal to 0.08 x C a6608701070120

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]3426 106131121151959595952525252511511511511513.513.513.513.513513513513520202020777750.050.050.050.0135 95 25 115 13.5 135 20 7 50.0 5 221101501416 6873789595252511511513.513.5135135111 95 25 115 13.5 135 20 7 50.0 - -90909010101010810810811.011.011.012512512520201818187766650.050.047.547.547.555555500022222222222299991102112124909090901616161610810810810811.011.011.011.012512512512518181818777747.547.547.547.5000012121212133 95 25 115 13.5 135 20 7 50.0 0 1213615718295959525252511511511513.513.513.5135135135173 95 25 115 13.5 135 20 7 50.0 5 22LA *: Additional nut length at each end when using combination wipers20202077750.050.050.0000121212121

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 80 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 3426:UltraSpeed nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 5.80.3,5.35.80.3,5.45.80.3,5.55.80.3,5.655558080808034563.53.53.53.523.930.637.143.481.2108.2135.3162.47009301150137010.80.7,5.310.80.7,5.410.80.7,5.510.80.7,5.6101010108080808034567.57.57.57.568.287.3105.8123.8164.3219.1273.8328.679010401280153015.80.11.315.80.11.415.80.11.515.80.11.61515151580808080345611.011.011.011.0134.4172.2208.6244.0283.9378.5473.1567.794012401540183020.80.11.320.80.11.420.80.11.520.80.11.62020202080808080345611.011.011.011.0134.2171.9208.2243.625.80.11.3 25 80 3 11.0 133.9 283.0 85030.80.11.3 30 80 3 11.0 133.5 282.4 7903426 25.80.9.10 25 80 5 + 5 9.0 301.0 847.9 309030.80.11.830.80.11.1040.80.11.440.80.11.63030404080808080* Actual stiffness at preload equal to 0.08 x C a4 + 45 + 52 + 23 + 311.011.011.011.0322.3394.9166.1245.1283.5377.9472.4566.9811.81028.2376.8592.19001180147017502420300010901620122

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 646974791051051051051616161612512512512513.513.513.513.514514514514520202020777755.055.055.055.000009999931041141251051051051051616161612512512512513.513.513.513.514514514514520202020777755.055.055.055.00000121212121211381531691251251251252525252514514514514513.513.513.513.516516516516525252525777765.065.065.065.00000121212121431641852061251251251252525252514514514514513.513.513.513.5177 125 25 145 13.5 165 25 7 65.0 5 22190 125 25 145 13.5 165 25 7 65.0 5 223426 157 125 25 145 13.5 165 25 7 65.0 5 221541841141541251251251252525252514514514514513.513.513.513.5165165165165165165165165LA *: Additional nut length at each end when using combination wipers25252525252525257777777765.065.065.065.065.065.065.065.0000055551212121222222222123

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 100 – 125 mmSingle nut, 4-point contactExecution grade P0 – P5■ Series 1416:DIN standard fl anged nut,ball oversize preload■ Series 3426:UltraSpeed nut with fl ange, dual start,ball oversize preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsiBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1416 10.100.7,5.310.100.7,5.410.100.7,5.510.100.7,5.61010101010010010010034567.57.57.57.575.096.0116.3136.1208.2277.6347.0416.491012001480177015.100.11.315.100.11.415.100.11.515.100.11.615151515100100100100345611.011.011.011.0152.2195.3236.7276.8373.2497.6622.0746.4118015601930230020.100.11.320.100.11.420.100.11.520.100.11.620202020100100100100345611.011.011.011.0152.4195.1236.4276.5372.9497.1621.4745.725.100.11.3 25 100 3 11.0 152.1 372.4 111011601520189022503426 30.100.11.830.100.11.1030.100.11.123030301001001004 + 45 + 56 + 611.011.011.0350.8429.9506.71001.41268.41535.430103740446040.100.11.440.100.11.640401001002 + 23 + 31416 10.125.7,5.4 10 125 4 7.5 105.1 350.8 134020.125.12,7.620.125.12,7.82025125125* Actual stiffness at preload equal to 0.08 x C a6811.011.012.712.7181.3267.5369.5473.2465.7731.81074.71433.01400209027003570124

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1416 931041141261251251251251616161614514514514513.513.513.513.5165165165165222222227777656565650000121212121271441591751501501501502525252517617617617617.517.517.517.520220220220230303030777777.577.577.577.50000121212121441641852061501501501502525252517617617617617.517.517.517.5202202202202177 150 25 176 17.5 202 30 7 77.5 5 2230303030777777.577.577.577.50000121212123426 15518521515015015025252517617617617.517.517.520220220230303077777.577.577.5555222222128168150150252517617617.517.51416 139 150 10 176 17.5 202 25 7 77.5 0 12217264170170252519619617.517.5202202222222LA *: Additional nut length at each end when using combination wipers30303030777777.577.587.587.5550022221212125

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 16 – 20 mmDouble nut, 2-point contactExecution grade P0 – P5■ Series 1516:DIN standard fl anged nutwith UNILOCK preload■ Series 2526:End cap nut with fl ange, dual start,pitch offset preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsi2xBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1516 2.16.1,5.32.16.1,5.44.16.3.34.16.3.45.16.3,5.35.16.3,5.42526 10.16.3,5.310.16.3,5.410.16.3,5.51516 2.20.1,5.22.20.1,5.32.20.1,5.42.20.1,5.54.20.3.24.20.3.34.20.3.45.20.3,5.25.20.3,5.35.20.3,5.410.20.3,5.210.20.3,5.3224455101010222244455510101616161616161616162020202020202020202020203434342345234234233 + 34 + 45 + 53 + 34 + 42526 10.20.3,5.5 10 20 5 + 5 3.5 25.2 32.5 5901.51.53.03.03.53.53.53.53.51.51.51.51.53.03.03.03.53.53.53.53.52.93.88.911.310.112.92.33.24.15.07.110.113.08.612.115.58.512.013.017.321.515.920.44.96.511.415.212.016.04.16.28.210.39.914.919.911.216.722.311.116.613.719.224.718.224.324033027036024032020030039048024035046023033044018027026034043037049020.20.3,5.220.20.3,5.3202020202 + 23 + 33.53.59.314.510.517.4150220* Actual stiffness at preload equal to 0.1 x C a126

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 25 mmDouble nut, 2-point contactExecution grade P0 – P5■ Series 1516:DIN standard fl anged nutwith UNILOCK preload■ Series 2526:End cap nut with fl ange, dual start,pitch offset preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsi2xBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1516 2.25.1,5.32.25.1,5.42.25.1,5.54.25.3.34.25.3.45.25.3,5.35.25.3,5.45.25.3,5.510.25.3,5.210.25.3,5.322244555101025252525252525252525345343453 + 34 + 45 + 523 2 x 31.51.51.53.03.03.53.53.53.53.53.54.55.511.414.613.717.521.218.123.128.09.613.6 17.97.810.413.019.325.721.528.735.923.431.239.014.321.4 23.312.28.4.4 12 28 4 4.0 22.1 37.2 5102526 15.25.3,5.215.25.3,5.320.25.3,5.220.25.3,5.315152020252525252 + 23 + 32 + 23 + 33.53.53.53.510.716.710.916.913.322.213.822.9350460570430570420550680460610750240360 39025.25.3,5.2 25 25 2 + 2 3.5 10.6 13.5 180* Actual stiffness at preload equal to 0.1 x C a250390220330128

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 32 mmDouble nut, 2-point contactExecution grade P0 – P5■ Series 1516:DIN standard fl anged nutwith UNILOCK preload■ Series 3526:UltraSpeed nut with fl ange, dual start,pitch offset preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsi2xBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1516 4.32.3.34.32.3.45.32.3,5.35.32.3,5.45.32.3,5.55.32.3,5.66.32.4.36.32.4.48.32.5.48.32.5.610.32.6.310.32.6.410.32.6.512.32.5.312.32.5.412.32.5.54455556688101010121212323232323232323232323232323232323434563446345453 + 34 + 45 + 53.03.03.53.53.53.53 + 3 4.04.04 + 4 5.05.03 + 32 x 42 x 56.06.06.03 + 3 5.05.05.013.116.816.020.424.829.018.724.031.544.630.839.447.821.327.333.026.335.029.839.849.759.624.8 32.743.741.5 52.078.040.351.662.645.660.876.032.443.254.0550730550730900107035.6 53071056.6 680100015.32.6.3 15 32 2 x 3 6.0 40.0 49.4 47020.32.6.3 20 32 3 6.0 30.2 44.9 3603526 20.32.6.220.32.6.320.32.6.425.32.6.230.32.6.220202025303232323232* Actual stiffness at preload equal to 0.1 x C a2 + 23 + 34 + 42 + 22 + 26.06.06.06.06.031.337.932.224.838.551.424.524.151.864.749.766.382.942.329.849.669.429.429.1490650800620760610800990600740540710880510330500670290250130

AView “A”PDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1516 7584879710711497110140174144165187191218829210250505050505091 5050132 50501301651873526 6888108505050166 505050101010101010101016161616161616166565656565656565656565656565656599999999999999998080808080808080808080808080808012121212121212121212121212666666667777731.031.031.031.031.031.031.031.031.031.031.031.031.0177 56 20 71 9 86 14 7 32.5 0 12200 50 16 65 9 80 12 7 31 0 127888565656565620202020207171717171999998686868686LA *: Additional nut length at each end when using combination wipers12121214141414147777777731.031.031.032.532.532.532.532.50000000000000000000559999999912121212121212121212122222131

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 40 mmDouble nut, 2-point contactExecution grade P0 – P5■ Series 1516:DIN standard fl anged nutwith UNILOCK preload■ Series 3526:UltraSpeed nut with fl ange, dual start,pitch offset preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsi2xBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1516 5.40.3,5.35.40.3,5.45.40.3,5.55.40.3,5.66.40.4.46.40.4.68.40.5.48.40.5.610.40.6.310.40.6.410.40.7,5.310.40.7,5.410.40.7,5.512.40.7,5.312.40.7,5.415.40.7,5.315.40.7,5.4555566881010101010121215154040404040404040404040404040404040345646463434534343 + 34 + 45 + 56 + 63.53.53.53.54 + 4 4.04.04 + 4 5.05.03 + 34 + 43 + 34 + 46.06.07.57.57.52 x 3 7.57.52 x 3 7.57.517.722.727.532.126.737.935.850.735.245.146.159.071.546.058.945.958.723.830.536.943.238.250.963.676.435.8 56.184.247.5 68.2102.346.459.460.477.359.679.571.395.1118.960.3 71.295.060.1 71.194.841.555.369.183.06708901100131061.0 880130074.2 870128064.986.677.8103.8640840630830103077.7 61081077.5 57076016.40.7,5.5 16 40 5 7.5 71.1 118.3 91020.40.7,5.220.40.7,5.320.40.7,5.43526 20.40.6.320.40.6.420.40.7,5.3 N20.40.7,5.4 N25.40.6.325.40.6.425.40.7,5.3 N25.40.7,5.4 N30.40.6.330.40.6.420202020202020252525253030404040404040404040404040402343 + 34 + 43 + 34 + 43 + 34 + 43 + 34 + 43 + 34 + 47.57.57.56.06.07.57.56.06.07.57.56.06.032.145.558.343.458.055.774.443.157.557.576.842.656.947.170.794.262.587.573.4102.862.186.977.5108.561.686.240.40.6.3 40 40 3 + 3 6.0 41.5 60.3 42034050067075099012301460980960710930700920670630670890650870600800620820540710132* Actual stiffness at preload equal to 0.1 x C aN: Alternate sizes acc. to DIN 69051

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1516 8999109125112137142176147167147167189152177180211849410411463636363106 6363134 63631361571361571532212633526 89109901101071321041291211516363636363152 6363180 63631010101010101010202016161620201616787878787878787878787878787878787899999999999999999939393939393939393939393939393939314141414141414141414141414141414146666667777777777735.035.035.035.035.035.035.035.035.035.035.035.035.035.035.035.035.0256 63 16 78 9 93 14 7 35.0 0 12636363636370706363707063631616162020252516162525161678787878788585787885857878999999999999993939393931001009393100100939314141414141414141414141414777777777777735.035.035.035.035.037.537.535.035.037.537.535.035.0148 63 16 78 9 93 14 7 35.0 5 22LA *: Additional nut length at each end when using combination wipers0000000000000000000000005555559999999912121212121212121212121212121212222222222222133

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 50 mmDouble nut, 2-point contactExecution grade P0 – P5■ Series 1516:DIN standard fl anged nutwith UNILOCK preload■ Series 3526:UltraSpeed nut with fl ange, dual start,pitch offset preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsi2xBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]1516 5.50.3,5.35.50.3,5.45.50.3,5.55.50.3,5.610.50.7,5.310.50.7,5.410.50.7,5.515.50.7,5.315.50.7,5.415.50.7,5.555551010101515155050505050505050505034563453454 + 45 + 56 + 63 + 34 + 43.53.53.53.57.57.57.57.57.57.519.625.130.435.652.767.481.752.567.281.434.041.248.269.589.048.965.281.597.892.3124.3155.493.0124.0155.070.888.5106.3101.5135.415.50.9.3 15 50 3 2 x 3 9.0 77.2 99.2 130.4 142.2 850 89015.50.9.3 N15.50.9.4 N15.50.9.5 N20.50.9.320.50.9.420.50.9.3 N20.50.9.4 N151515202020205050505050505034534342 x 3 9.09.09.02 x 3 9.09.09.09.077.298.8119.776.898.476.898.499.2 130.4173.9217.498.7 130.0173.3130.0173.3810107013201570810106013107609901230142.2 85011201380141.7 780102078010203526 20.50.7,5.4 N 20 50 4 + 4 7.5 87.2 137.4 118025.50.7,5.4 N 25 50 4 + 4 7.5 86.7 136.8 109030.50.6.430.50.7,5.3 N30.50.7,5.4 N35.50.7,5.3 N35.50.7,5.4 N303030353550505050504 + 43 + 34 + 43 + 34 + 46.07.57.57.57.563.964.586.163.985.4108.997.2136.096.6135.240.50.7,5.3 N 40 50 3 + 3 7.5 63.3 95.9 63011901470176089011808908109807501010690920134* Actual stiffness at preload equal to 0.1 x C a

Positioning ball screws 16 - 125 mmNOMINAL DIAMETER 60 – 63 mmDouble nut, 2-point contactExecution grade P0 – P5■ Series 1516:DIN standard fl anged nutwith UNILOCK preload■ Series 3526:UltraSpeed nut with fl ange, dual start,pitch offset preloadTechnical dataNut typeLeadP[mm]Nominaldiameterd N[mm]No. ofcircuitsi2xBalldiameterd W[N]Dyn. loadratingC a[kN]Stat. loadratingC 0a[kN]Stiffness*R nu, ar[N/μm]3526 25.60.9.325.60.9.4252560603 + 34 + 49.09.0107.4143.4179.0250.51160156030.60.9.330.60.9.4303060603 + 34 + 49.09.0106.8142.7178.3249.61090146035.60.9.3 35 60 3 + 3 9.0 106.2 177.5 102040.60.9.240.60.9.3404060602 + 23 + 39.09.068.0105.5106.0176.620.63.7,5.4 20 63 4 + 4 7.5 97.0 172.5 15001516 5.63.3,5.45.63.3,5.55.63.3,5.610.63.7,5.310.63.7,5.410.63.7,5.510.63.7,5.6555101010106363636363636345634563 + 34 + 45 + 53.53.53.57.57.57.57.527.833.739.559.275.891.8107.478.8100.7122.084.3105.4126.5120.7160.9201.1241.3131.3175.0218.8126015601870100013101620193015.63.9.4 15 63 4 2 x 4 9.0 116.7 150.3 239.9 261.2 1510 159020.63.11.320.63.11.420.63.11.52020206363633452 x 32 x 42 x 511.011.011.0115.3147.7179.0148.3189.9230.1209.1278.8348.5228.0303.9379.930.63.11.3 30 63 3 11.0 114.4 207.8 920* Actual stiffness at preload equal to 0.1 x C a107014101740620950111014601800112014801830136

AView “A”PShape BShape CDimensionsFlanged nut with wipers both endsL F[mm]D 1 g6[mm]L 1[mm]D 4[mm]D 5[mm]D 6[mm]L 7[mm]L 3[mm]H[mm]A[mm]LA *[mm]1516 941041141271051051051051616161612512512512513.513.513.513.514514514514520202020777755.055.055.055.0000099991531741942151431741941051051051051616161612512512512513.513.513.513.514514514514520202020777755.055.055.055.00000121212122112432743042741251251251252525252514514514514513.513.513.513.516516516516525252525777765.065.065.065.00000121212122432843463862843861251251251252525252514514514514513.513.513.513.5302 302 125 25 145 13.5 165 25 7 65.0 5 22430 430 125 25 145 13.5 165 25 7 65.0 5 22340 125 25 145 13.5 165 25 7 65.0 5 223526 124154184114154125125125125125252525252514514514514514513.513.513.513.513.5165165165165165165165165165LA *: Additional nut length at each end when using combination wipers25252525252525252577777777765.065.065.065.065.065.065.065.065.0000055555121212122222222222139

www.setec-group.itwww.setec-group.itTORINO TORINODirezione Generale eDirezione Generale - Headquarter:ViaStabilimentoMappano,di17Produzione- 10071 Borgaro- HeadquarterT.se (TO)and Production Plant :TVia+39Mappano,011 451 861117(centr. - 10071r.a.)Borgaro +39 011T.se470(TO)4891T +39 011 451TORINODirezione 8611 setec.to@setec-group.it(centr.Generale r.a.)- Headquarter:- F +39 011 470 4891Via Mappano, setec.to@setec-group.it17 - 10071 Borgaro T.se (TO)T +39 011 451 8611 (centr. r.a.) - F +39 011 470 4891setec.to@setec-group.itMILANOMILANO Via Meccanica, 520026 Via Meccanica, Novate (MI) 5- Z. I. Vialba20026T +39Novate02 356 0990 - 382 01 590 (r.a.)F +39(MI) MILANO02- Z.356I.0943VialbaT +39 02 356 setec.mi@setec-group.it0990 Via - Meccanica, 382 01 590 5(r.a.)F 20026 +39 02 Novate 356 0943 (MI) - Z. I. VialbaT +39 02 356 0990 PADOVA- 382 01 590 (r.a.)setec.mi@setec-group.itF +39 Via02Secchi,356810943setec.mi@setec-group.itPADOVA 35136 PadovaViaT +39 049 872 5983FSecchi,+39 049 PADOVA 81856 096535136 setec.pd@setec-group.itVia Secchi, 8135136 PadovaPadovaT +39 049 872 5983T +39 - F049 +39872 0495983856 0965setec.pd@setec-group.itF +39 049 856 0965setec.pd@setec-group.itHIWIN GW ENG HIWIN REV02GW ENG REV02Distribuito da / Distributed by:www.setec-group.itwww.setec-group.itBOLOGNAVia Del Lavoro, BOLOGNA 6/A40051 Via Altedo Del Lavoro, (BO) 6/AT +39 051 871 949 (3 linee r.a.)F +39 BOLOGNA 40051 051 870 Altedo 329 (BO)T setec.bo@setec-group.it+39 Via Del 051 Lavoro, 871 949 6/A(3 linee r.a.)40051 F +39 Altedo 051 (BO)870 329T +39 051 871 FIRENZE949 (3 linee r.a.)ViaF +39 setec.bo@setec-group.itGalileo051 870Galilei,329350015setec.bo@setec-group.itBagno a Ripoli FIRENZE - Grassina (FI)T +39 055 643 261F +39 Via FIRENZE055 Galileo 646 6614 Galilei, 350015 setec.fi@setec-group.itVia Galileo Galilei, 350015 Bagno Bagnoa Ripoli a Ripoli Grassina - Grassina(FI)(FI)T +39 055T +39 643055 261643 -261F +39 055 646 6614F +39 setec.fi@setec-group.it055 646 6614setec.fi@setec-group.it