Vehicle brake device

摘要

A vehicle brake device is provided with a master cylinder, a master piston slidably arranged in the master cylinder, an input piston slidably arranged in the master cylinder to be separated from the master piston and defining a separation chamber, an input piston moving amount detecting section for detecting the moving amount of the input piston, a master piston moving amount calculating section for calculating the moving amount of the master piston based on the moving amount of the input piston, and a contact inferring section for inferring the contact of the input piston with the master piston based on the moving amount of the input piston and the moving amount of the master piston.

主权项

1. A vehicle brake device for supplying brake fluid to a wheel cylinder of a friction brake provided for a wheel to generate a friction brake force by the friction brake, the vehicle brake device comprising:
a master cylinder; a master piston arranged in the master cylinder slidably in an axial direction and composed of a pressurizing piston portion defining together with an internal surface of the master cylinder a master chamber for pressurizing the brake fluid supplied to the wheel cylinder, a servo pressure receiving portion defining together with the internal surface of the master cylinder a servo chamber filled with the brake fluid, and a protruding portion protruding rearward from a rear end of the pressurizing piston portion; an input piston arranged at a rear part in the master cylinder slidably in the axial direction, being behind the protruding portion to be separated from the protruding portion, and defining together with the internal surface of the master cylinder and the protruding portion a separation chamber filled with the brake fluid; an input piston moving amount detecting section that detects the moving amount of the input piston; a servo pressure generating section that generates a servo pressure acting in the servo chamber, in dependence on the moving amount of the input piston detected by the input piston moving amount detecting section; a master piston moving amount calculating section that calculates the moving amount of the master piston based on the moving amount of the input piston detected by the input piston moving amount detecting section; and a contact inferring section that infers the contact of the input piston with the protruding portion based on the moving amount of the input piston detected by the input piston moving amount detecting section and the moving amount of the master piston calculated by the master piston moving amount calculating section.