| 摘要 |
PURPOSE:To provide the titled planetary ring gear extremely enhanced in the durability of the brake lining and the ring gear surface thereof, obtained by manufacturing the planetary ring gear from low alloyed case hardening steel and applying carburizing treatment only to the surface of the ring gear cone thereof in a perfect carbonization protecting treatment state. CONSTITUTION:A fine pitch planetary gear part 1b and an one-way clutch bearing part 1c receiving the action of high surface pressure are provided to the planetary ring gear 1 for a car semi-automatic transmission (SAT) other than a ring gear cone surface 1a. In this case, the gear 1 is manufactured by using about 0.2wt% of case hardening steel and receives proper carburization hardening treatment. On the other hand, in order to prevent the abrasion of a brake lining 6 and to suppress the baking, heat crack and plastic flow at the ring gear cone surface 1a, the surface roughness of said surface 1a is set to 3muRz or less and the surface hardness thereof is set to a range of Hv 300-450. As a result, the durability of the brake lining and the ring gear cone surface can be remarkably enhanced.
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