Ring gear, internal combustion engine-starting torque-transmission mechanism, and method of manufacturing ring gear

摘要

A ring gear is formed by joining a race side-region formed body, a gear side-region formed body and an intermediate region formed body. Accordingly, it is possible to perform processing of an inner race portion of the race side-region formed body with none of the gear side-region formed body and the intermediate region formed body present. By causing the gear side-region formed body and the intermediate region formed body to absorb changes in design depending on the type of internal combustion engine, it is possible to standardize the size and the shape of the race side-region formed body for various engine types. Because the inner race portion, as well as a disposition surface and a contact surface for the seal rings are formed on the same race side-region formed body, it is possible to finish the surfaces with precise positional relationship.