Hydraulic pressure brake unit for vehicle; has negative pressure booster unit to boost movement of main cylinder piston operated by brake pedal and pump to increase brake fluid pressure independently

摘要

The brake unit has a main cylinder (10) with a piston operated by a brake pedal (2) to increase a brake fluid pressure in a reservoir (4). A negative pressure booster unit boosts the movement of the main cylinder piston by a negative pressure corresponding to the brake pedal movement. A pump (HP) increases the brake fluid pressure of the reservoir independently of the main cylinder. A hydraulic pressure booster unit has a working chamber (RP) behind the main cylinder piston to supply hydraulic pressure from the pump to the working chamber, to support the main cylinder piston and a valve, which controls a booster force on the main cylinder piston. An individual reaction force component between the main cylinder piston and the hydraulic pressure booster unit transmits a reaction force to the brake pedal.