PUMP DISPLACEMENT CONTROL CIRCUIT

摘要

A displacement changer for switching the displacement of a variable displacement hydraulic pump by performing switching control of a switching valve by a control signal from a detection means, wherein a first spring chamber and a second spring chamber is short-circuited. The detection means detects deceleration of a vehicle traveling by a hydraulic motor and, when the deceleration is at a previously set standard value, the detection means outputs a control signal. The switching valve is switched from a non-communication position to a communication position to short-circuit the first spring chamber and the second spring chamber, stopping the discharge from the variable displacement pump. As a result, even if the hydraulic motor is suddenly stopped by a mechanical brake, pressure rise of pressurized oil discharged from the pump is suppressed.