초록 ▼

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 th

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.

대표청구항 ▼

A pressure control actuator fluidly disposed in a fluid-pressure line, comprising: a shut-off valve fluidly disposed in said fluid-pressure line, said shut-off valve being responsive to a valve-open signal for establishing a fluid communication between upstream and downstream lines of said valve, an

A pressure control actuator fluidly disposed in a fluid-pressure line, comprising: a shut-off valve fluidly disposed in said fluid-pressure line, said shut-off valve being responsive to a valve-open signal for establishing a fluid communication between upstream and downstream lines of said valve, and responsive to a valve-closing signal for blocking said fluid communication and for shutting a fluid pressure in said downstream line; a pressure-regulation cylinder slidably accommodating therein a piston having a piston rod and cooperative with said piston for defining therein a variable-volume pressure chamber which is fluidly connected to said downstream line; a thrust generator drivingly connected to said piston for producing a thrust acting on said piston; and spring means for biasing said piston in a first axial direction when said piston is shifted apart from its neutral position in a second axial direction opposite to said first axial direction under a fluid pressure introduced into said chamber so that a volume of said chamber is enlarged, wherein a pre-load of said spring means is set to balance with a force acting on said piston by a maximum fluid pressure introduced into said chamber; and wherein said piston rod comprises a stepped piston rod, and said spring means includes a return spring and a movable annular spring seat formed separate from said stepped piston rod and having an outside diameter greater than an inside diameter of a radially inwardly projecting annular shoulder formed on an inner wall of said cylinder so that said spring seat is spring-loaded against said annular shoulder by said pre-load of said spring, and an outside diameter of a larger diameter section of said piston rod is dimensioned to be greater than an inside diameter of said annular spring seat so that said piston is positioned in the neutral position by abutment between said larger diameter section of said stepped piston rod and said spring seat abutting with said shoulder.