Kabushiki Kaisha Komatsu Seisakusho

Hideaki Tohma

Kazuo Uehara

Yoshito Sato

A hydraulic control system for a variable displacement pump, comprising a prime mover for driving the variable displacement pump, a fixed displacement pilot pump driven by the common prime mover, a pressure compensating valve connected to the pilot pump and the variable displacement pump, a cut-off control valve connected to the pressure compensating valve and the variable displacement pump, and a servo booster connected to the cut-off control valve and the pilot pump for controlling the displacement of the variable displacement pump.

Hydraulic control system for variable displacement pump

A hydraulic control system for variable displacement pumps, comprising at least two variable displacement pumps, a prime mover for driving the variable displacement pumps, a fixed displacement pilot pump driven by the common prime mover, a pressure compensating valve comprising a two-stage proportional pressure reducing valve and a negative proportional pressure reducing valve, the pressure compensating valve being connected to the variable displacement pumps and the fixed displacement pilot pump, and at least two servo boosters each being mechanically connected to the respective variable displacement pumps for controlling the displacement therefrom, the servo boosters being connected to the fixed displacement pilot pump and the pressure compensating valve and controlled thereby.

Hydraulic control system for variable displacement pumps

A control system for a variable displacement pump which powers a load actuator via a selector valve and which has its displacement varied by a pump actuator of the single-acting type. The system includes a load-sensing control valve for selectively communicating the pump actuator with a pressurized fluid source or with a fluid drain in accordance with a differential between the sum of the pump output pressure and the pump actuator pressure and the sum of the load actuator pressure and the force of a spring. Also included is a normally open, cutoff control valve, connected serially with the load-sensing control valve, for placing the pump actuator in communication with a fluid drain in response to the sum of the pump output pressure and pump actuator pressure acting against the force of a spring.

Growing community of inventors

Yokohama, Japan

Hideaki Tohma