Brake having a pressure responsive slack adjuster

摘要

A brake device equipped with an actuator having a power-transmission member generating a pushing force by receiving a drive force so as to advance. A pressure-detection device is provided for detecting the reaction pressure being applied to the power-transmission member and a clearance controller is provided for making the power-transmission member perform a return stroke. A brake shoe is attached to the power-transmission member and generates a braking force on the wheel tread surface. Such clearance controller is provided with a stroke memory unit which detects when the pressure signal from the pressure-detection device has reached a reference value when the pushing force of the power-transmission member is output and memorizes the stroke position of the power-transmission member as the reference stroke position. A computational processor determines the return stroke position by which the power-transmission member is separated from the wheel tread surface and the clearance stroke fraction established in advance using the reference stroke position, when the pushing force is released.