Vehicle brake control unit

A vehicle brake control unit comprising:

• a pressure source for generating a pressure independently of operation of a brake operating member;
• braking booster means for adjusting the pressure from said pressure source according to a force applied to the brake operating member to apply an adjusted pressure to wheel brakes;
• emergency-braking-operation detecting means for detecting an emergency braking operation;
• and
• brake pressure change-over means for communicating said pressure source with the wheel brake when said emergency-braking-operation detecting means detects an emergency braking operation, said brake pressure change-over means being in fluid communication with the pressure source via the braking booster means;
• said braking booster means comprising:
• a cylinder body into which the pressure is led from said pressure source;
• a regulator pressure chamber formed in said cylinder body;
• a spool member provided in said cylinder body, said spool member being moved axially to adjust the pressure of said pressure source upon receiving a brake operating force on one side thereof and the pressure in said regulator pressure chamber on the other side thereof;
• and a regulator port formed in said cylinder body, to which the adjusted pressure adjusted by said spool member is led, said regulator port being communicating with said wheel brakes;
• and
• wherein said brake pressure change-over means comprises a change-over valve which selectively takes a first position to communicate said wheel brakes with said regulator port and to isolate said wheel brakes from said pressure source, and a second position to communicate said wheel brakes with said pressure source, and to isolate said wheel brakes from said regulator port.

A vehicle brake unit, comprising:

• a pressure source;
• a cylinder body having an inlet port to which said pressure source is connected in which a high hydraulic pressure is stored, a regulator port to which wheel brakes are connected, and a drain port to which a reservoir is connected;
• a regulator pressure chamber connected to said regulator port;
• a sliding member which is slidably provided in said cylinder body, said sliding member being moved in one direction by a brake operating force to communicate said regulator port with said inlet port, and being moved in the other direction by a fluid pressure in said regulator pressure chamber to communicate said regulator port with said drain port;
• a fluid pressure modulator coupled to a pipe line through which said regulator port is connected to said regulator pressure chamber, to adjust the fluid pressure in said regulator pressure chamber to a fluid pressure different from the fluid pressure in said regulator port;
• emergency-braking-operation detecting means for detecting an emergency braking operation;
• and
• fluid-pressure-modulator driving means for driving said fluid pressure modulator according to a detection output of said emergency-braking-operation detecting means.