| 摘要 |
PURPOSE: To provide a pressure controller to be easily structurally integrated with a pump with less structure costs by making a closing mechanism receive the pressure of a hydraulic pressure system againt the force of a spring device on one side and receive the pressure or negative pressure between a hydraulic pump and a suction throttle valve on the other side. CONSTITUTION: The suction throttle valve 2 is provided with the closing mechanism of a piston 20 for which a load is put to an open position by the spring device 21 and the closing mechanism is has a structure for receiving the pressure of the hydraulic pressure systems 5 and 6 on one side against the force of the spring device 21 and receiving the pressure or the negative pressure present between the hydraulic pump 3 and the suction throttle valve 2 on the other side. Then, since reproducible limited hysteresis in the switching operation of the suction throttle valve is generated by the utilization of the negative pressure, ON/OFF control is automatically performed without an additional control valve. Thus, formation is performed at a less structure costs and structural integration with the pump is easily performed. |
