Shaft supporting structure and method for manufacturing shaft supporting device

摘要

An object of the present invention is to support a shaft with high reliability in strength without having to increase the diameter of the shaft more than necessary. Provided is an output shaft supporting structure that supports an output shaft (10) with (a first and) a second tapered roller bearing (42), in which the output shaft has a second larger diameter portion (15) where the second tapered roller bearing is placed, and a small diameter portion (17) that is disposed to be adjacent to the second larger diameter portion. An axial-direction movement of an inner ring (42A) of the second tapered roller bearing on the output shaft is regulated by a retaining ring (61), and a collar (60) is fitted into the small diameter portion through interference fitting.