Load sensitive hydraulic device

Abstract

Abstract PURPOSE:To control pressure of a pump effectively, by varying the valve opening force of a pilot valve controlling relief pressure of a balance piston type relief valve circulating surplus oil of the pump to a tank by pressure at an inlet side of an actuator. CONSTITUTION:When an actuator 1A becomes active, the opening force of a pilot valve 20 is varied by pressing the spring of the pilot valve 20 by inlet side pressure through ducts 12b, 31a. As it becomes, therefore, that an opening of the pilot valve 20 is throttled according to the magnitude of a load and a balance piston type relief valve 13 is relieved by pressure corresponding to an actual load, through which the titled device is controlled so that a quantity of delivery of a pump 2 is increased by reducing pilot pressure to be sent to a pump 2 side. In addition to the above, a secondary side duct of the balance piston type relief valve 13 can be communicated with a tank 3 directly by making the pump 2 into a fixed capacity one.

Inventors

• 👤 Toshinari Sumiyoshi
• 👤 住吉　俊成

Bibliographic Details