Kobelco Construction Machinery Co., Ltd.

Yoshio Nishimoto

Takahiro Kobayashi

Etsujiro Imanishi

Taisuke Tsunoo

Satoshi Yonezawa

A winding-down side pilot port of a control valve is of a 2-port construction comprising a normal winding-down side port having a large pressure receiving area and a free fall side port having a small pressure receiving area, wherein in the free fall operation carried out by setting a motor to a small capacity, a pilot pressure of a winding-down side remote control valve is supplied to the free fall side port through a mode switching valve. Thereby, a stroke of the control valve can be suppressed so that a speed of a motor does not exceed an allowable speed.

Control device for hydraulic drive winch

According to the present invention, when a winch drum is in the wind-down rotation, operating a control valve is operated to the wind-down side in a state in which capacity of a hydraulic motor is set to small capacity by a free fall valve to thereby rotate the hydraulic motor to the wind-down side at high speeds, and at the same time, motor holding pressure is controlled according to an operating amount of the free fall valve by a holding pressure control valve to thereby regulate rotational speed of the hydraulic motor and stop the latter.

Growing community of inventors

Kobe, Japan

Yoshio Nishimoto