Kobe Steel, Ltd.

Kobelco Construction Machinery Co., Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Takayuki Igaue

Naoki Sugano

Satoshi Maekawa

Kei Morita

Mitsunori Hirozawa

Provided is an electrically-driven flow rate control valve capable of controlling a flow rate of fluid while application of a high pressure of the fluid to a sub valve body connected to an electric motor is suppressed. A flow rate control valve includes a casing, an elevation drive device, and a main valve body. When the sub valve body moves upward by the elevation drive device, oil in a back pressure chamber is discharged. Moreover, the oil in a first oil chamber flows into the back pressure chamber while the flow rate of the oil is regulated. A balance among pressures in the back pressure chamber, the first oil chamber, and the second oil chamber changes, and the main valve body opens. When the main valve body is closed, a direct application of the pressure of the back pressure chamber to the sub valve body is blocked.

Electrically-driven flow rate control valve

Provided is an electrically-driven flow rate control valve capable of controlling a flow rate of a fluid flowing between two inlet/outlet ports, restraining a high pressure of the fluid from being applied to a sub valve body connected to an electric motor. The flow rate control valve has a casing, a raising/lowering drive device, a supply-switching valve, a main valve body, a valve-closing spring. When the electric motor of the raising/lowering drive device moves the sub valve body upward, oil of a back pressure chamber is discharged from a discharge oil passage through a sub valve body communication port and a sub valve body oil passage to open the main valve body. When the main valve body is closed, a pressure of the back pressure chamber is inhibited from being directly applied to a lower end face of the sub valve body.

Provided is a hydraulic driving apparatus including a calculation section calculating a temporary target engine rotation speed corresponding to an engine operation amount, a calculation section calculating a temporary target pump displacement volume based on first-control and second-control target pump displacement volumes corresponding to an actuator operation amount and a pump load pressure, and a command section calculating a final target engine rotation speed and a final target pump displacement volume to output commands. The command section calculates a target pump discharge amount from the temporary target engine rotation speed and the temporary target pump displacement volume, sets the final target pump displacement volume to one larger than the temporary target pump displacement volume, and sets the final target engine rotation speed to one being lower than the temporary target engine rotation speed and allowing a pump discharge amount equivalent to the target pump discharge amount to be obtained.

Growing community of inventors

Kobe, Japan

Takayuki Igaue