ANTI-LOCK DEVICE FOR VEHICLE BRAKE

PURPOSE: To simplify the structure of an anti-lock device so as to reduce cost by connecting the discharge side of a return pump for returning a pressure medium at the time of anti-lock operation, to a master cylinder through a pressure limiting device. CONSTITUTION: An anti-lock device 2 with a built-in check valve 10 opened at the time of pressure drop is interposed at an intermediate part of a brake fluid conduit communicating the outlet of a master cylinder 3 with wheel brakes 4, 5, and an anti-lock valve device 11 for returning a part of a brake fluid to the suction side of a hydraulic tank 15 and a return tank 16 to decompress the wheel brakes 4, 5 is provided at an intermediate part of the brake fluid conduit. In such a device, an outlet 18 of the return pump 16 is connected to the master cylinder 3 through a pressure limiting device 21 that can be opened toward the master cylinder 3, and pressure buildup is suppressed by actuating the pressure limiting device 21 by pressure buildup at the time of wheel lock with an extremely large quantity of a pressure medium led out of the wheel brakes 4, 5.