PISTON CUP, BRAKE CHAMBER DEVICE, AND ACTUATOR DEVICE

摘要

The present invention addresses the problem of providing a piston cup configured with the consideration of both the smooth movement of the piston and the sealing characteristics of the piston cup. A piston cup (7) is provided with: an engagement section (16) engaging with the piston (4); a sealing section (18) provided closer to one end of the piston cup (7) in the movement direction (X) of the piston (4) than the engagement section (16); and a guide section (22) provided at a different position from the sealing section (18) in the movement direction (X) of the piston (4) and guiding the piston (4). The guide section (22) has a first top section (23). The sealing section (18) has a second top section (20a). In a state in which the first top section (23) and the second top section (20a) are in contact with the inner surface (2a) of the chamber, the portion (24) between the first top section (23) and the second top section (20a) is lower than the first top section (23) and the second top section (20a) in the thickness direction (Y).