摘要 |
Braking device including a master cylinder ( 2 ), a primary piston ( 3 ), a control member ( 4 ), a booster ( 6 ) coupled to the control member ( 4 ), and an assist valve (VA) defined by a reaction piston ( 17 ) with a bore ( 18 ) therein for receiving a ratio control member ( 24 ). The control member ( 24 ) has a piston ( 29 ) with a head ( 25 ) located in a chamber ( 26 ) between the reaction piston ( 17 ) and a bushing ( 27 ) retained in the bore ( 18 ). The bushing ( 27 ) has an axial passage ( 28 ) that receives a head ( 25 ) of piston ( 29 ) to form a valve ( 36 ) for closing an inlet to a passage ( 30 ) in the piston ( 29 ). The bushing ( 27 ) slides within bore ( 18 ) to limit a pressure difference between the chamber ( 26 ) and a front part ( 18 a) of the bore ( 18 ) to a value below a pressure difference that causes the valve ( 36 ) to open. |