| 摘要 |
A servo-assisted hydraulic control device for motor vehicles, comprising an actuator (10,12) for operating the vehicle brake pedal (14) and/or accelerator pedal (16) by a manual command (18), characterised by comprising: a hydraulic circuit with a reservoir (8), a pump (4), a member (6) for controlling the pressure in said circuit and a hydraulic control unit (2), a cylinder (20) housing in its interior a piston (26) which divides the internal cavity of said cylinder into three chambers, namely a pressure chamber connected to the hydraulic circuit, a thrust chamber connected to said actuator (10,12), and a control chamber operationally interposed between the two, at least one valve (64) housed in said piston (26) and axially movable relative thereto between a position in which it opens and a position in which it closes passage between the pressure chamber and the control chamber, at least one valve (28) mounted within said piston (26) and inserted between said reservoir (8) and the thrust chamber of said cylinder (20) to interrupt its communication when said piston (26) is moved from its rest position, a member (24) movable axially relative to said piston (26) to operate said valve (64), and provided with means (58,60,56,54) for communication between the control chamber of said cylinder (20) and said reservoir (8), means (62) interposed between said member (24) and said valve (64) to independently cause closure of said communication means (58,60,56,54) and activation of said valve (64), in relation to the position of said member (24) and said piston (26), and a lever (18) for manually controlling the axial movements of said member (24). <IMAGE> |
