Machinery's Handbook, 31st Edition
2422
Thrust Bearings
1.0
0.5
0.1
0.05
0.01
1
5
Z 2 l 10
50
100
Fig. 4. Kinetic Energy Correction Factor, ξ —Thrust Bearings. a
a See footnote on page 2418 Example: Design a flat plate thrust bearing to carry 900 pounds load at 4000 rpm using an SAE 10 oil with a specific heat of 3.5 Btu/gal/ ° F at 120 ° F and 30-psi inlet conditions. The shaft is 2 3 ⁄ 4 inches in diameter and the temperature rise is not to exceed 40 ° F. Fig. 5 shows the final design of this bearing. 1) Inside diameter. Assumed to be 3 inches to clear shaft. 2) Outside diameter. Assuming a unit bearing load of 75 pounds per square inch from Table 1, . . D 08 75 4 900 3 5 30 inches 2 2 # # # π = + = Use 5 1 ⁄ 2 inches. 3) Radial pad width. . . a 2 = 55 3 125inches − = 4) Pitch-line circumference. . . B 4 25 13 35 inches # π = = 5) Number of pads. Assume an oil groove width of 3 ⁄ 16 inch. If length of pad is assumed to be equal to width of pad, then . . . i 125 01875 133 9 app = + = + If the number of pads, i , is taken as 10, then
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