Roller Chain - Tsubaki
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Roller Chain - Tsubaki

Roller Chain - Tsubaki Roller Chain - Tsubaki

tsubaki.ca
12.07.2015 Views

Roller ChainInstallation & MaintenanceDrive Chain6.2 Inspection IntervalsRegular inspection of roller chain is recommend at one-monthintervals. Inspection should be carried out at shorter intervals inthe following cases.1. Special or corrosive environments2. High speeds with sudden stoppage3. Lifting or indexing operations6.3 Inspection requirements for ordinary transmission1) Inspecting condition of lubrication1) While the chain is driving, check to see if there islubrication in the clearance between the outer link plateand inner link plate. Also check if the chain or rotating discis immersed in lubricating oil.2) When the chain is stationary, the chain surface willgenerally appear dirty from wear dust if lubrication isunsatisfactory. This is especially the case between the linkplates.3) When the chain is removed, connecting link pins and theedge of the inside of the bushings should be checked. Ifthere are any scratches, red or reddish-brown color,lubrication is improper or insufficient.2) Inspection of link plates1) If repeated loads over the maximum allowable load are puton the chain, there is a strong possibility of fatiguebreakage of the link plate. It is difficult to notice initialcracking from fatigue breakage simply from externalobservation.3) Inspection of pinsWhen the pins rotate, the roller chain must be completelyreplaced with new chain. This also applies to the connectingpins. By removing the connecting parts it is possible to see theconditions of wear and rust on the surfaces of the pins.Fig. 25 Rotation of the pins4) Inspection of the rollers1) As with the link plates, if rollers are also subjected to loadsover the maximum allowable load, the repeated impactload between the chain and the sprockets may causefatigue breakage to occur. The roller should be checked inthe same way as the link plate.2) If foreign objects interfere with the engagement of theroller and sprocket, the roller may be damaged and acrack may develop. Careful attention should be paid to theabove. In high-speed operations, even if foreign objectsdo not interfere with engagement, cracks may appear fromthe impact with the sprocket teeth.3) Chains damaged from fatigue breakage of the rollers mustbe completely replaced, because each part has receivedthe same amount of repeated load.2) Usually, a crack develops at the edge of a hole or at theside of the link plate, as shown in the illustrations below.The presence of cracks should be checked carefully.Fatigue breakage progresses little by little, so it can benoticed if close attention is paid.HFig. 23 Cracks on the link platesH × 5%Example of a crackFig. 24 Wear on the edges of the link plates3) When wear occurs from sliding between the edges of theplates and the guides, it is necessary to adjust the positionof either the chain or the guides. The allowable wear onthe link plates is limited to 5% of their height.Fig. 26 Cracks on the rollers4) Also check if the roller rotation is poor.5) Inspection of the sprockets1) Chain and sprocket engagement can be checked byobserving the roller and surface of the teeth. Properengagement is when the contact area is uniform with pointA in the illustration (figure 27). If the contact area islopsided or the sides of the teeth are wearing away (pointB in figure 27), this may have been caused from improperinstallation of the sprockets or twisting of the roller chain.In this case, rechecking/readjustment is necessary.2) The normal point of impact is slightly up from the toothbottom. However, when initial tension is applied to thechain and tension remains on the slack side, the roller willslightly touch the tooth bottom. However, point A (figure27) receives the strongest impact.A-114

Roller ChainInstallation & Maintenance3) When idlers or tensioners are used, the contact area willbe the center of the tooth bottom.ImproperinstallationImproper installation causesthe surface of the teeth tobecome ground down.Fig. 27 Contact area of the sprocket teeth4) Sprockets generally need to be replaced when tooth wear(shown in table 4) has been reached. Sprockets withinduction hardened teeth need to be replaced when thehardening layer is worn.6) Inspection of chain elongation1) Chain elongation is caused not by deformation of the linkplate, but by wear on the pin and bushing. Therefore, theremaining chain life can be estimated by periodicallymeasuring the chain elongation.2) Measuring chain elongation(1) The chain should be measured while stretching itslightly to eliminate any slack.(2) Measure the distance of the inside (L 1 ) and outside (L 2 )of the rollers at both ends of the measured links using acaliper, to get a measurement (L).L= L 1 + L 22(3) When measuring, use at least 6 to 10 links to help keepany measuring error down to a minimum.Drive ChainSprocket Replacement Guide(Based on Tooth Thickness/Dimension B)Table 4All dimensions in inches unless otherwise stated.Size of RS Dimension BRoller Chain Normal Pin-GearRS 11 0.024 —RS 15 0.043 —RS 25 0.059 —RS 35 0.098 —RS 41 0.102—RS 40 0.0980.106RS 50 0.1140.134RS 60 0.1460.169RS 80 0.1970.228RS100 0.2720.307RS120 0.3430.390RS140 0.4170.469RS160 0.4880.559RS180 0.4450.535RS200 0.4960.591RS240 0.5940.713RF320T 0.7830.957RF400T 0.980Size of BSRoller ChainDimension BNormalRS05B 0.063RF06BRS08BRS10BRS12BRS16BRS20BRS24BRS28BRS32BRS40B0.0630.0830.1140.1420.1970.2680.2830.3390.4690.500Note: Pin-Gear tooththicknesses are all 18T.5) If a new roller chain is run on a worn sprocket, the chainwill wear at a faster rate than normal. In this case, whenreplacing the chain, replacement of the sprocket is alsorecommended.Fig. 28 Measurement of length(4) Finding the chain elongationChain elongation (%) = Measured length – Standard length × 100Standard lengthStandard length = Chain pitch × Number of links(5) For multi-strand roller chain, the measurement is carriedout in the same way as for single strand roller chain ofthe same pitch.(6) The limit of usage based on roller chain elongation for asmooth transmission is as follows.Table 5Maximum allowable elongationLarge sprocket with up to 60 teeth Chain elongation 1.5%Large sprocket with between 61 - 80 teeth Chain elongation 1.2%Large sprocket with between 81 - 100 teeth Chain elongation 1.0%Large sprocket with between 101 - 110 teeth Chain elongation 0.8%A-115

<strong>Roller</strong> <strong>Chain</strong>Installation & Maintenance3) When idlers or tensioners are used, the contact area willbe the center of the tooth bottom.ImproperinstallationImproper installation causesthe surface of the teeth tobecome ground down.Fig. 27 Contact area of the sprocket teeth4) Sprockets generally need to be replaced when tooth wear(shown in table 4) has been reached. Sprockets withinduction hardened teeth need to be replaced when thehardening layer is worn.6) Inspection of chain elongation1) <strong>Chain</strong> elongation is caused not by deformation of the linkplate, but by wear on the pin and bushing. Therefore, theremaining chain life can be estimated by periodicallymeasuring the chain elongation.2) Measuring chain elongation(1) The chain should be measured while stretching itslightly to eliminate any slack.(2) Measure the distance of the inside (L 1 ) and outside (L 2 )of the rollers at both ends of the measured links using acaliper, to get a measurement (L).L= L 1 + L 22(3) When measuring, use at least 6 to 10 links to help keepany measuring error down to a minimum.Drive <strong>Chain</strong>Sprocket Replacement Guide(Based on Tooth Thickness/Dimension B)Table 4All dimensions in inches unless otherwise stated.Size of RS Dimension B<strong>Roller</strong> <strong>Chain</strong> Normal Pin-GearRS 11 0.024 —RS 15 0.043 —RS 25 0.059 —RS 35 0.098 —RS 41 0.102—RS 40 0.0980.106RS 50 0.1140.134RS 60 0.1460.169RS 80 0.1970.228RS100 0.2720.307RS120 0.3430.390RS140 0.4170.469RS160 0.4880.559RS180 0.4450.535RS200 0.4960.591RS240 0.5940.713RF320T 0.7830.957RF400T 0.980Size of BS<strong>Roller</strong> <strong>Chain</strong>Dimension BNormalRS05B 0.063RF06BRS08BRS10BRS12BRS16BRS20BRS24BRS28BRS32BRS40B0.0630.0830.1140.1420.1970.2680.2830.3390.4690.500Note: Pin-Gear tooththicknesses are all 18T.5) If a new roller chain is run on a worn sprocket, the chainwill wear at a faster rate than normal. In this case, whenreplacing the chain, replacement of the sprocket is alsorecommended.Fig. 28 Measurement of length(4) Finding the chain elongation<strong>Chain</strong> elongation (%) = Measured length – Standard length × 100Standard lengthStandard length = <strong>Chain</strong> pitch × Number of links(5) For multi-strand roller chain, the measurement is carriedout in the same way as for single strand roller chain ofthe same pitch.(6) The limit of usage based on roller chain elongation for asmooth transmission is as follows.Table 5Maximum allowable elongationLarge sprocket with up to 60 teeth <strong>Chain</strong> elongation 1.5%Large sprocket with between 61 - 80 teeth <strong>Chain</strong> elongation 1.2%Large sprocket with between 81 - 100 teeth <strong>Chain</strong> elongation 1.0%Large sprocket with between 101 - 110 teeth <strong>Chain</strong> elongation 0.8%A-115

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