| 摘要 |
A pressure control actuator suitable for an automotive brake control system comprises a pressure-regulation cylinder slidably enclosing a piston and cooperative with the piston for defining therein a variable-volume pressure chamber which is fluidly connected to a wheel cylinder, a shut-off valve through which the variable-volume chamber is connected to a master cylinder, a motor-driven thrust generator drivingly connected to the piston for producing a thrust, and a heavily pre-loaded return spring for biasing the piston in a first direction opposite to a second direction in which the piston is pushed by the master-cylinder pressure shut-up in the chamber, when the piston is displaced apart from its neutral position in the second direction so that the volume of the chamber is enlarged. A pre-load of the spring is set to balance with a force acting on the piston by a maximum master-cylinder pressure introduced into the chamber. In the absence of thrust acting on the piston after termination of the ABS pressure-reduction control, the piston quickly and precisely returns to the neutral position. Zero-thrust ensures a quick recovery of the piston to the neutral position at the aid of light braking action after termination of the TCS pressure-intensifying control. |
