Improvements in hydraulic anti-skid braking systems for vehicles.

摘要

In an hydraulic anti-skid braking system for a vehicle of the four wheel type in which an anti-skid modulator (2) is adapted to control the brake (6) on a rear wheel, an apportioning valve (10) is incorporated in a line between each modulator (2) and the brake (6), and a pressure responsive control valve assembly (20) is also incorporated in the line. The valve assembly (20) comprises a pressure-responsive member, for example piston (23) working in a bore (22), and operable when subjected to a differential pressure in excess of a predetermined value, to restrict the effective area of passage (27) through which fluid is dumped from the brake (6). This reduces the rate at which the pressure is released from the rear brake (6), thereby enabling this brake to do more work. Hence the stopping distance for the vehicle can be shortened.