A rotary fluid pressure device, such as a low-speed, high-torque gerotor motor, is provided with a valve drive shaft that is partially inserted into and engaged with a main drive shaft as the main drive shaft engages a rotating output shaft and engages a rotating and orbiting star member of a positive displacement device. The device is also provided with a drive retainer configured to retain the engagement of the main drive shaft and the valve drive shaft.

A solenoid valve includes: a cylindrical spool that has an annular groove in an outer surface and moves along an axial direction under a driving force generated by a current being applied to a solenoid part; a cylindrical sleeve that has a through-hole capable of communicating with the annular groove and houses the spool; and an urging member that urges the spool by an urging force acting in a direction opposite from a direction in which the driving force is generated. When no current is applied to the solenoid part, a part of the through-hole communicates with the annular groove. When a current is applied to the solenoid part, an area of communication between the through-hole and the annular groove increases as the spool moves under the driving force acting against the urging force.

An oil pump device includes a motor, a pump, a pump cover, and a solenoid. The pump cover includes a discharge port, an intake opening through which oil is suctioned, a first discharge opening and a second discharge opening through which oil is discharged, a first oil passage that is a flow path between the first discharge opening and the discharge port, and a second oil passage that is a flow path between the second discharge opening and the discharge port. A solenoid valve of a solenoid is located on the second oil passage.

The application relates to an internal gear machine for reversing duty having a housing with a chamber, in the chamber there are disposed an externally toothed pinion and an internally toothed ring gear, which mesh with one another, the rotational axes of which run parallel to and spaced apart from one another. The chamber in the housing is axially bounded and is connected via pressure pockets provided in the housing to pressure connections in the internal gear machine. According to the invention, a switching valve is arranged in each connection between the pressure pockets and the pressure connections or compression spaces, which valve opens or closes the connection.

A vane rotary compressor may include a main bearing and a sub bearing provided with a plurality of back pressure pockets each having a different pressure formed on a surface facing the cylinder, a rotational shaft radially supported by the main bearing and the sub bearing, a roller provided with a back pressure chamber that communicates with the plurality of back pressure pockets and having a plurality of vanes configured to divide a compression space into a plurality of compression chambers. At least one of the main bearing or the sub bearing is provided with an oil supply passage that communicates with a back pressure pocket having a relatively low pressure among the plurality of back pressure pockets. Accordingly, oil may be smoothly supplied to a back pressure pocket having a low pressure.

A diverter valve housing is secured to an upper end of a pump. A shuttle in the diverter valve housing moves between an upper closed position and a lower open position. A floating ring has an exterior band that abuts an upper end of the shuttle to move the shuttle downward. The floating ring moves upward when the pump operates. A bushing abuts an upward facing shoulder in the floating ring and is adhered within the bushing by a layer of adhesive. The shuttle has upper and lower seals separated by upper and lower spacer rings. A stop ring between the spacer rings limits downward movement of the upper spacer ring and also limits upward movement of the lower spacer ring.

A compressor includes two rotors opposed to each other in an axial direction, and a vane contacting the rotors. While the vane is moved in the axial direction with rotation of the rotors, the vane is restricted from rotating by a vane groove. The compressor includes compression chambers in which suction and compression of fluid are performed with rotation of the rotors, and a communication mechanism switched between a communicating state in which the compression chambers communicate with each other, and a non-communicating state in which the compression chambers do not communicate with each other.

Disclosed herein are embodiments of magnetically controlled valve and pump systems that can be used to control and facilitate fluid flow in fluidic devices. Various types of magnetically controlled valves and pumps are described as well as methods of magnetically-controlling such valves and pumps.

Methods and apparatus pertaining to positive displacement pumps, and further to hydraulic actuation systems. In some embodiments the pumps are gear pumps with bi-directional operation. In some embodiments the actuation system includes a motor-driven, reversible operation gear pump providing fluid under pressure to a rod and cylinder.

A pump apparatus includes a housing, a shaft, a rotor, a plurality of vanes, a pressure relief passage, and a bearing. The housing includes suction ports and discharge ports. The rotor and the vanes transport hydraulic oil to the discharge ports. The hydraulic oil is sucked from the suction ports. The pressure relief passage is defined in a portion of the housing facing an outer peripheral surface of the shaft. The pressure relief passage brings the discharge ports into communication with a low pressure region where the hydraulic oil is low in pressure. When a pressure of the hydraulic oil in the discharge ports is lower than a first predetermined pressure, the bearing keeps the pressure relief passage out of communication with a passage. When the pressure of the hydraulic oil in the discharge ports has increased to reach or exceed the first predetermined pressure, the bearing brings the pressure relief passage into communication with the passage.