RING GEAR MOUNTING STRUCTURE

摘要

A ring gear mounting structure is configured such that a ring gear (10) is fitted onto a supporting portion (8), and the ring gear (10) abuts against a stopper portion (11) that protrudes from on one end portion of the outer peripheral surface (9) in a rotational axis direction of the ring gear (10). A groove (14) is formed in a portion of the outer peripheral surface (9) that is on the stopper portion (11) side of the outer peripheral surface (9). A portion of the outer peripheral surface (9), which is on a side opposite the stopper portion (11) across the groove (14), is a press-fitting surface (20) that the ring gear (10) is press-fitted onto and contacts. A predetermined gap (C1, C2) is formed in a radial direction of the ring gear (10) and the rotational axis direction of the ring gear (10).