Nippon Air Brake Kabushiki Kaisha

Kenichi Shimoura

Masahiro Tsunemi

Yuji Kondo

A hydraulic motor control circuit for use in a device for driving construction equipment, such as shovel loader, which comprises a hydraulic driving motor, a pump for feeding compressed oil to the hydraulic motor and a tank for receiving the compressed oil discharged from the hydraulic motor. The circuit comprises a pilot operation type main valve for controlling the oil flow between the pump and the motor and between the motor and the tank, and a remote control valve for feeding a pilot oil pressure to a pilot chamber of the main valve to turn the main valve to a first position for driving the hydraulic motor. As a feature of this invention, the control circuit further comprises an apparatus for detecting the slanting angle of a downward slope and feeding an oil pressure corresponding to the slanting angle to a second pilot chamber of the main valve. The main valve is adapted to turn from its first position to its second position in which the speed of rotation of the hydraulic motor is confined in accordance with the slanting angle.

Growing community of inventors

Kobe, Japan

Kenichi Shimoura