Patent attributes
A forward/reverse change-over mechanism (3) of an automatic transmission comprises a forward clutch (5) inside a drum (7) with the base (7c) which rotates together with an input shaft (1). The forward clutch (5) engages by driving a piston (9) housed in the drum (7) by the oil pressure of an oil chamber (10) between a base (7c) and the piston (9). Projecting bearings (16) which seat the piston (9) are formed by press-forming at equal angular intervals concentrically with the axial center of the drum (7) in the base (7c). By installing a sensor body (18) which responds to the passage of depressions (17) formed underneath the bearings (16), the forward/reverse change-over mechanism (3) can be made compact and manufactured with a small number of parts and machining steps.
