| 主权项 |
1. A ring gear mounting structure comprising:
a supporting portion of which an outer peripheral surface has a circular shape; a ring gear fitted onto an outer periphery of the supporting portion; a stopper portion that protrudes radially outward from the outer peripheral surface on one end, in a rotational axis direction of the ring gear, of the outer peripheral surface, the stopper portion being to abut against the ring gear; a groove recessed toward an inner peripheral side in a radial direction, in a first portion of the outer peripheral surface, the first portion being on a stopper portion side of the outer peripheral surface; and a press-fitting surface that the ring gear is press-fitted onto and contacts, at a portion of the outer peripheral surface, the second portion being on a side opposite the stopper portion across the groove; wherein a predetermined gap includes a first predetermined gap defined in a radial direction of the ring gear, between an inner peripheral surface of the ring gear and a boundary portion of the outer peripheral surface that is a boundary between the groove and the press-fitting surface, and wherein the groove and the press-fitting surface are connected by a connecting surface, a cross-section, along the rotational axis direction of the ring gear, of the connecting surface is an arc-shape, and a center portion in a width direction of the connecting surface is the boundary portion. |
