Aisin Seiki Kabushiki Kaisha

Naoki Oogushi

Hideki Nakayoshi

A tandem pump apparatus having a first hydraulic pump for supplying operating fluid to a first actuator and a second hydraulic pump for supplying operating fluid to a second actuator in cooperation with each other is disclosed. Each hydraulic pump is provided with a flow rate control valve for refluxing a surplus of flow discharged from the pump to a suction side of the pump through a relief passage. A connecting passage connects the first relief passage downstream from the first flow rate control valve and the second relief passage downstream from the second flow rate control valve. A check valve is provided in the connecting passage for allowing operating fluid to flow from one of the relief passages that has a relatively great reflux flow rate to the other relief passage having a relatively small reflux flow rate, thereby ensuring sufficient supercharge into the two pump to achieve sufficient restraint of cavitation.

Tandem pump apparatus

A tandem pump apparatus is featured having a main suction passage connected to a fluid source. The main suction passage branches into first and second suction passages which, in turn, feed into first and second pumps. Each pump discharges a portion of the fluid to a return passage that is fluidly connected to the suction port of each respective pump. In each return passage, a return control valve is disposed to control the amount of fluid returned to the suction port. The tandem pump featured in this invention exhibits increased efficiency and decreased noise.

When one chamber of vane pump is located at an end of a discharge process and is compressed at maximum, pressure in the chamber is higher than the discharge pressure of the pump. Vanes are supported in slits of a rotor. A passage connecting the one chamber and inner sides of the vanes in the slits supplies pressure to push the vanes onto an inner surface of a cam-ring of the pump.

Vane pump having vane pressurizing grooves

A fluid pressure driving system for a vehicle includes a reservoir tank in which an amount of fluid is stored, a variable capacity oil pump sucking the fluid from the reservoir tank and discharging the resultant fluid, a control device for adjusting a quantity of the fluid discharged from the variable oil pump, and a distributor valve having an inlet port for receiving the fluid from the variable capacity oil pump. The distributor valve discharges a fixed amount of the fluid and the remaining amount of the fluid from a first outlet port thereof and a second outlet port thereof, respectively. A first passage connects the first outlet port of the distributor valve and the reservoir tank. A second passage connects the second outlet port of the distributor valve and the reservoir tank. A power steering device is associated with a steering wheel and disposed in the first passage. A hydraulic motor is disposed in the second passage, and a cooling fan is mounted rotatably on the hydraulic motor.

Growing community of inventors

Kariya, Japan

Naoki Oogushi