Komatsu Corporation

Kiyokazu Nakabo

Fujitoshi Takamura

Seiichi Fuchita

Harushige Nishida

Tomio Teranaka

A control circuit for a piece of heavy machinery reduces a speed of one actuator, having a lower load, when that actuator and another actuator, having a higher load, are operated simultaneously. The control circuit includes a first control valve for supplying a first actuator with pressurized oil, discharged from a hydraulic pump; a second control valve for supplying a second actuator with pressurized oil, discharged from the hydraulic pump; operating units for actuating the first control valve and the second control valve; and a mode selector for providing a command to the second control valve in order to increase a speed of the first actuator compared with that of the second actuator when the first and second actuators are operated simultaneously. A variable adjustor can be provided to control the open area of a valve for enabling the stroke of the spool of the second control valve to regulated. The control circuit can include a sensor for detecting pilot pressure applied to the first control valve; a sensor for detecting pilot pressure applied to either end of the second control valve; a solenoid valve for passing pilot pressure to pilot ports at both ends of the second control valve; and a controller for actuating said solenoid valve responsive to signals from the two sensors.

Growing community of inventors

Kyoto, Japan

Kiyokazu Nakabo