Caterpillar Sarl

Atsunobu Doi

Yusuke Shimizu

Hiroyasu Nishikawa

Sei Shimahara

Masashi Shibata

Manabu Nakanishi

Seiichi Akiyama

A hydraulic pump driven by an engine, a hydraulic actuator, and a negative control circuit are provided on an open center hydraulic circuit, for guiding the hydraulic pressure in the center bypass to the hydraulic pump, as a negative control pressure. A negative control pressure control device controls the negative control pressure to an arbitrary value is also provided. The pump characteristic of the hydraulic pump is set such that the discharge flow rate is minimized when the negative control pressure in the negative control circuit is equal to or greater than a first predetermined pressure. Furthermore, an idling detection device that detects whether the hydraulic actuator is in a non-operated state or not is provided. The negative control pressure is forcefully controlled to the first predetermined pressure or higher when the non-operating state is detected.

Growing community of inventors

Tokyo, Japan

Atsunobu Doi