摘要 |
An anti-skid hydraulic braking system for a vehicle having the usual wheel cylinders, master cylinder and brake pedal, with a brake release valve interposed ahead of each wheel cylinder for selectively reducing the pressure in the wheel cylinder in accordance with a slip signal generated at the associated wheel upon going into a relatively slipping condition of incipient skid. Each brake release valve has an inlet port connected to the master cylinder, an outlet port connected to the wheel cylinder, and a control port. In the preferred embodiment the valve has a first or "signal" piston movable in response to slip signal pressure applied to the control port and a second piston for creating a cavity for temporary accommodation of brake fluid from the wheel cylinder. When the pressure at the control port rises, signaling an incipient skid, movement of the signal piston first cuts off the inlet port to isolate the wheel cylinder from the rest of the regular braking system and then shifts the second piston to create a cavity for accommodating slight reverse flow of fluid from the wheel cylinder, thus relieving the brake pressure sufficiently to avoid a skid. The inlet-outlet ports are bridged by a check valve to insure immediate release of the wheel cylinder upon release of the brake pedal. In an alternate form of the invention utilizing an electrical slip signal, the signal piston is replaced by a solenoid plunger.
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