75mm to 180mm SPLIT TAPERED BEARINGS

75mm to 180mmSplit tapered BEARINGsBulkhead sealingIt is often found economical to combine a bearing andbulkhead seal into one unit. This reduces the number ofindividual units required, and prevents problems with shafteccentricity sometimes encountered at the bulkhead seal whenit is separated from the bearing.Generally, a specially adapted flange mounting is used and thebearing is fitted with SRSRP seals (see page 6). Generally, theflange incorporates additional sealing to the cartridge seating,and may include sealing on the mounting face (‘backface’).Where the shaft surface speed is too high for standardSRSRP seals, an alternative high speed version is available, oralternative seal types can be used if a moderate leakage ofwater is permitted through the bearing in an emergency.Sealing to flange mounting face (“BFS”)Sealing to swivel seating (“SSE”)SRSRP SealCombined bearing and bulkhead sealBearing SelectionBearing ratings for dynamic radial capacity (Cr) and static radialcapacity (Cor) shown in this leaflet are in accordance with ISO281-1990 and ISO 76-1987 respectively.Radial and axial loads must be considered together ascombined ‘equivalent loads’, as explained below. Generally,maximum instantaneous loading is governed by housingstrength rather than bearing static capacity.Dynamic ratingExpected bearing life is calculated by the following equation:L10 = [Cr/(P x fd)] (10/3)where:L10 = expected life of 90% of similar bearingsunder similar operating conditionsCr = radial dynamic ratingP = equivalent dynamic loadfd = dynamic or service factor, generally from1 for steady loading to 3.5 for heavy shock,reciprocation or vibrationThe dynamic equivalent load is calculated as follows:when F a /F r ≤e :when F a /F r >e :P = F r + Y 1 F aP = 0.67F r + Y 2 F awhere:F r = applied radial loadF a = applied axial loadand calculation factors Y 1 , Y 2 and e are given in the productdata tables.Life calculation with multiple load conditionsWhere varying loads are experienced in operation, using themaximum load condition may lead to an unrealistically lowcalculated life. For n load conditions constituting the full loadcycle (at constant speed), an overall dynamic equivalent loadmay be calculated as follows:i=n0.3P = [∑P (10/3) i p i ]where:P ip ii=1= dynamic equivalent load under loadcondition i= proportion of time load condition i isapplicableWhere the load is continuously variable it may be brokendown into a discrete approximation to the actual load cycle.Minimum loadingIn order to avoid excessive skidding of the rollers, sufficientloading must be applied to the bearing, as follows:P ≥ 0.01Cr2