This invention relates to deceleration detecting valves adapted for use with vehicles such as automobiles or the like.
Deceleration detecting valves are widely used in hydraulic braking systems of vehicles such as automobiles, which systems usually comprise a master cylinder, a first circuit connecting the master cylinder with front wheel brakes, and a second circuit connecting the master cylinder with rear wheel brakes through a deceleration detecting valve. When the deceleration exceeding a predetermined amount occurs during application of the brakes, the deceleration detecting valve is actuated to cut off the supply of pressurized oil to the rear wheel brakes thereby preventing the so-called skidding phenomenon, increasing the braking efficiency and maintaining the directional control of the vehicle.
However, there is a shortcoming in such a hydraulic braking system is that when a failure occurs in the first circuit connecting the master cylinder with the front wheel brakes, and deceleration exceeding the predetermined amount occurs during braking of the vehicle by the rear wheel brakes, the deceleration detecting valve is actuated to cut off the supply of pressurized oil to the rear wheel brakes whereby the vehicle cannot sufficiently be braked. Accordingly, when a failure occurs in the circuit for the front wheel brakes, the rear wheel brakes cannot apply the desired braking force to the vehicle.