Kabushiki Kaisha Komatsu Seisakusho

Komatsu Corporation

Fujitoshi Takamura

Takumi Onoda

Yukio Moriya

Seiichi Fuchita

Toshio Yokoyama

Yoshinao Haraoka

Junichi Tanaka

Takeshi Kobayashi

Tetsuya Nakayama

Shuki Akushichi

Harushige Nishida

Kiyokazu Nakabo

Tomio Teranaka

Controller of engine and variable capacity pump

A controller, for a variable capacity pump, prevents engine stalls due to rapid changes in operating load by increasing the pump absorption torque when the engine speed is high so as to increase the work amount and by reducing the pump absorption torque when the engine speed is low. The controller receives a signal from an engine speed sensor for detecting engine speed. A pump absorption torque curve is pre-set so as to be consecutively stepped with respect to engine speed so as to intersect at an engine rated point. The pump absorption torque is then calculated in accordance with increases or decreases in engine speed. The pump absorption torque is then set to prescribe values based on the results of these calculations and an instruction is outputted to a control valve in such a manner as to regulate a regulator of the variable capacity pump.

Control device for variable capacity pump

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.

Control circuit for heavy machinery

Controller for hydraulic drive machine

Control device for hydraulically operated machine

Apparatus for changing and controlling volume of hydraulic oil in

Fine operation mode changeover device for hydraulic excavator

Hydraulically-operated equipment such as travelling equipment or working equipment for use in construction machinery such as a power shovel, shoveldozer and bulldozer. The hydraulically-operated equipment comprises a hydraulic driving mechanism actuated by hydraulic pressure, a hydraulic pressure supplying device for supplying hydraulic pressure to a hydraulic pipeline system for the hydraulic driving mechanism and a controller for controlling the hydraulic pressure supplying device such that the supplying rate at which hydraulic pressure is supplied to the hydraulic pipeline system according to the supply of hydraulic pressure is decreased in a specified period after a dead zone period in which hydraulic pressure starts to rise. This arrangement prevents an operational lag in the hydraulic driving mechanism as well as a shock at the time of start-up and shut-down.

Growing community of inventors

Hirakata, Japan

Fujitoshi Takamura