| 摘要 |
PURPOSE:To ensure safety, when a power fluid pressure disappears, by mounting a regulator piston to be fitted to a power pressure fluid chamber in a master cylinder and providing in this regulator piston a valve device which connects a regulator chamber selectively to the power pressure fluid chamber or a reservoir. CONSTITUTION:In a housing 1a of a master cylinder 10 which mounts a master piston 11 to be fitted to a cylinder hole 10a, forming a regulator hole 30a communicating with the cylinder hole 10a through a communication hole 18d, a regulator piston 31 is slidably fitted to this regulator hole 30a. While mounting a control piston 18 to be interposed between the master cylinder 10 and a regulator 30, a regulator chamber 30b is formed between this control piston 18 and the regulator piston 31. And providing a valve device 32, which connects the regulator chamber 30b selectively to a power pressure fluid chamber 37b or to a reservoir 41, in the regulator piston 31, a power fluid pressure can be adjusted to the predetermined brake fluid pressure. |
