| 摘要 |
A brake system includes a master cylinder which is operable to communicate pressurized fluid to a wheel assembly in order to brake the latter. The wheel assembly is capable of spinning or skidding under excessive acceleration or deceleration, respectively, and an electronic control unit cooperates with a modulator valve and a pressure source to compensate for spinning or skidding by controlling the communication of pressurized fluid from the modulator valve to the wheel assembly. The modulator valve communicates with the pressure source and the master cylinder and includes a first bore for slidably supporting a piston assembly and a second bore for slidably supporting a plunger. The piston assembly cooperates with a modulator valve housing to define a storage chamber and the pressure source is operable to move the plunger to a position communicating the master cylinder and the wheel assembly with the storage chamber. The piston assembly comprises at least three pistons, two of which define pressure chambers and the third defines the storage chamber. At least two solenoid valves are coupled to the control unit so that one of the solenoid valves is actuated upon skidding to vent one of the pressure chambers and the other solenoid valve is actuated upon spinning to vent the other pressure chamber. A first piston includes a projection extending through a bore in the second piston to oppose a third piston. |
