PRESSURE OIL FEED CIRCUIT DEVICE FOR HYDRAULIC CYLINDER OF OPERATION MACHINE.

摘要

The device includes a larger diameter piston (9) for operating the capacity regulation member (8) of a variable capacity pump (2) in such a direction as to reduce the pump capacity. A smaller diameter piston (10) operates the capacity regulation member (8) of the variable capacity pump (2) in such a direction as to increase the pump capacity. The smaller diameter piston (10) has a small diameter piston pressure receiving chamber (10a) connected to the pump discharge passage (2a). A load sensing valve (11) establishes cuts off communication between the pressure receiving chamber (9a) of the larger diameter piston and the pump discharge passage.