Automatic transmission

摘要

An automatic transmission (3) has a transmission casing (8) accommodating a transmission mechanism and a filter case (50) attached to the transmission casing (8) and having an oil filter. The transmission casing (8) has a concave portion (88c) with which at least an oil inlet (60) or an oil outlet (61) communicates and an overhanging portion (83b) positioned close to the concave portion (88c) and extending along a surface (90c) of the transmission casing (8) with a clearance (K) provided between the surface (90c) and the overhanging portion (83b). The filter case (50) has a case body (51) inserted into the concave portion (88c), a seal member (52) sealing a boundary between an outer circumferential surface (51a) of the case body (51) and an inside surface of the concave portion (88c), a first brim portion (53) protruding from the outer circumferential surface (51a) and fixed to the surface (90c) of the transmission casing (8), and a second brim portion (54) protruding from the outer circumferential surface (51a) and inserted into the clearance (K).