Patent ID: 6120113
Filing Date: 2000-09-19
Classification: B60T

Abstract:
A hydraulic braking system for an automotive vehicle having a pair of hydraulic pressure circuits for braking each wheel of said vehicle, a reservoir for storing brake fluid, and a master cylinder for pressurizing the brake fluid fed from said reservoir and supplying hydraulic pressure to said hydraulic pressure circuits in response to depression of a brake pedal, at least one of said hydraulic pressure circuits comprising:a first wheel cylinder operatively mounted on a first wheel of said vehicle for braking said first wheel;a second wheel cylinder operatively mounted on a second wheel of said vehicle for braking said second wheel;a first passage for communicating said master cylinder with said first and second wheel cylinders;first pressure control means disposed in said first passage for controlling the hydraulic pressure in said first wheel cylinder;second pressure control means disposed in said first passage for controlling the hydraulic pressure in said second wheel cylinder;an auxiliary pressure source having an inlet for introducing the brake fluid from said first and second wheel cylinders through said first and second pressure control means, respectively, and an outlet for discharging pressurized brake fluid to said first and second wheel cylinders through said first and second pressure control means, respectively;a second passage for communicating said master cylinder with the inlet of said auxiliary pressure source;valve means disposed in said first passage and connected to said second passage for being selectively positioned in one of a first operating position for communicating said master cylinder with said first and second pressure control means, and blocking communication between said master cylinder and the inlet of said auxiliary pressure source, and a second operating position for communicating said master cylinder with the inlet of said auxiliary pressure source and blocking communication between said master cylinder and said first and second pressure control means, wherein said valve means comprises a normally open two-port two-position valve disposed in said first passage and having one port connected to said master cylinder and the other port connected to said first and second pressure control means, and a normally closed two-port two position valve having one port connected to said master cylinder and the other port connected to said second passage;at least one auxiliary passage for communicating said master cylinder with at least one of said first and second wheel cylinders to supply hydraulic pressure from the master cylinder to the at least one of said first and second wheel cylinders; andat least one switching valve disposed in said auxiliary passage for opening and closing said auxiliary passage.