| 摘要 |
PROBLEM TO BE SOLVED: To stably obtain a desired lubricity by properly correcting a position of an oil groove. SOLUTION: In this thrust plate 7, front and back surface side thrust surfaces 12 and the like are provide with oil grooves 15 and 16. In this case, the oil grooves 15 and 16 are symmetrically positioned such that when the thrust plate 7 is rotated around any of three axes X, Y, and Z by 180 deg., each of the oil grooves 15, 16 comes in the same position. In the front surface side thrust surface 12, a pair of surface side oil grooves 15 are disposed at both sides of the straight line Y on the plane of the plate 7 and at a position symmetrical with respect to the plate center line Z. In the back surface side thrust surface, a pair of the back surface side oil grooves 16 are symmetrically placed against the surface side oil groove 15 with respect to the straight line Y. Accordingly, difference between the front surface and back surface of the thrust plate 7 disappears, and the oil grooves are necessarily in the same positions thereby stably obtaining desired lubricity.
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