Hydraulic braking system with road wheel anti-lock feature - has dual pressure circuits with separate pumps on single drive, grouped slave cylinder controls and reduced hydraulic vibration

摘要

A dual circuit hydraulic braking system employs separate pumps (11,12) connected in anti phase with common drive (m) and supplying circuits (I) and (II) respectively). In normal circumstances a master cylinder (1) with servo vacuum intensifier (2) and having twin chambers (3 4), controls the slave cylinders (not shown) on front and rear wheels via inlet valves (7) and outlet valves (8) with pumps (11,12) stationary. Locking of the road wheels is anticipated by sensors (not shown) causing motor (M) to start and enabling pumps (11 12) to adjust braking torque to point of limiting slip via inlet/outlet valves (7,8) and pressure balancer (19) independently of master cylinder pressure. ADVANTAGE - System does not generate rapid pressure oscillations and noise of other methods. Does not require expansion chambers or additional valves in conduit system which increase oil volume and pedal travel or retard response due to temp sensitivey and blockages.