TWO-SYSTEM ANTILOCK TYPE PRESSURE FLUID BRAKE DEVICE

PURPOSE:To enable a normal side brake device to hold its fluid pressure to a proper value, by setting a target wheel speed, which is set in accordance with an estimated car body speed, so that a difference between the target wheel speed and the estimated car body speed increases larger when a defect is detected in one system of the two-system brake devices. CONSTITUTION:The captioned device, which detects in a wheel speed detecting means E a rotary speed of wheels A, B in each group of plural wheels divided into two groups estimating a car body speed in accordance with the detection output being based on the maximum of the wheel speeds in a target speed setting means F, sets a target wheel speed lower than this estimated speed. And the device, when the speed of each wheel decreases lower than the target wheel speed, controls a brake fluid pressure by a fluid pressure control unit G so that the wheel speed increases to almost the target wheel speed. Here the device is constituted setting the target wheel speed so that its difference from the estimated car body speed increases larger than normal by a defect-time control means I when a defect in one of the two systems is detected by a defect detecting means H.