Machinery's Handbook, 31st Edition
Thrust Bearings
2427
U
h 1
h 2 δ
b 2
b 1
b Fig. 7. Basic Elements of Tapered Land Thrust Bearing.* 1) Inside diameter, D 1 . Determined by shaft size and clearance. 2) Outside diameter, D 2 . Calculated by the formula D K P W D 4 g a 2 1 2 2 1 π = + c m where K g = 0.8 or 0.9 and W = applied load, pounds P a = assumed unit load from Table 1, page 2418 3) Radial pad width, a. Equal to one-half the difference between the inside and outside diameters. a D D 2 2 1 = − 4) Pitch-line circumference, B. Found from the mean diameter: B D D 2 1 2 π = + ^ h 5) Number of pads,i. Assume an oil groove width, s , and find the approximate number of pads, assuming the pad length is equal to a . i a s B app = + Then i is taken as the nearest even number. 6) Length of pad, b. Readily determined because the number of pads and groove width are known. b i B is = − 7) Taper values, δ 1 and δ 2 . Can be taken from Table 2. 8) Actual bearing unit load, p. Calculated in pounds per square inch from the formula p iab W = 9) Pitch-line velocity, U. Found in feet per minute at the pitch circle from the formula U BN = 12 where N = rpm 10) Oil leakage factor, Y L . Found either from Fig. 8 which shows curves for Y L as func tions of the pad width a and length of land b or from the formula Y b a b 1 12 L 2 2 2 π = + ⁄ 11) Film thickness factor, K. Calculated using the formula . K UY Z p 575 10 L 6 # = * See footnote on page 2418
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