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.

An electric pump system and method of operating the same involves pumping a fluid through a fluid passageway defined in a mechanical pump from a pump inlet to a hollow shaft of a motor, through the hollow shaft to an internal motor cavity defined by a housing of the motor, and through another fluid passageway defined in the motor housing and mechanical pump that leads to a pump outlet. The system and method further involve pumping the fluid through another fluid passageway defined in the mechanical pump from yet another pump inlet to the pump outlet. The temperature of fluid exiting the hollow shaft can be assessed and used by an electronic control unit (ECU) of the electric pump system to control the same. The electric pump system can be part of a cooling and lubrication system for an electric vehicle transmission, gearbox, differential or transfer case, for example.

A disc valve assembly for control of a flow of hydraulic fluid in a hydraulic fluid system may include a disc element comprising an inlet facing side and a second side opposite to the inlet facing side, and flow pathways configured as a plurality of different pressure zones with the flow pathways extending axially along a longitudinal axis of the disc element from at or adjacent to the inlet facing side to the second side. A valve housing houses the disc element and includes porting configured as part of the plurality of different pressure zones respectively in fluid communication with the flow pathways of the disc element. The disc element is configured to rotate to control a flow of hydraulic fluid through the disc valve assembly. The different pressure zones are isolated from each other using a plurality of annular sealing rings located on the inlet facing side of the disc element.

A hydraulic motor includes a rotor and a stator, wherein the rotor and the stator define a plurality of motor pockets for receiving a flow of hydraulic fluid, and the rotor rotates relative to the stator based on a pressure differential between the motor pockets. A commutator having porting controls the flow of hydraulic fluid into the motor pockets. The rotor rotates about a first axis and the stator orbits about a second axis, and the stator is configured to orbit such that the second axis orbits about the first axis. The commutator is eccentrically piloted about the first axis and the second axis so that the commutator both rotates and orbits to control the flow of hydraulic fluid into the motor pockets. With such configuration, an output shaft is driven by rotation of the rotor about the first axis without orbiting, obviating the need for a drive link.

An electric pump system and method of operating the same involves pumping a fluid through a fluid passageway defined in a mechanical pump from a pump inlet to a hollow shaft of a motor, through the hollow shaft to an internal motor cavity defined by a housing of the motor, and through another fluid passageway defined in the motor housing and mechanical pump that leads to a pump outlet. The system and method further involve pumping the fluid through another fluid passageway defined in the mechanical pump from yet another pump inlet to the pump outlet. The temperature of fluid exiting the hollow shaft can be assessed and used by an electronic control unit (ECU) of the electric pump system to control the same. The electric pump system can be part of a cooling and lubrication system for an electric vehicle transmission, gearbox, differential or transfer case, for example.

A hydraulic machine (1) has a working section (6) and a fluid control section (28). The fluid control section includes a spool (3) that is rotatable in a cylindrical bore (30) about an axis (4). A distributor plate (18) extends intermediate of the control section and the working section. The spool includes an axial recess (10) which is axially bounded by a radially extending annular wall (44). A front face (48) of the annular wall rotates in abutting engagement with a plate face contact area (50) of the distributor plate. Hydraulic fluid flows through at least one groove (52) that extends radially and circumferentially across the abutting areas of the spool and the distributor plate to provide lubrication and heat absorption.

A shaft (1) is shown comprising a shaft section (2) having an axis (3), a tooth geometry (4) at least at one end of said shaft section, said tooth geometry (4) having a first end (5) opposite said shaft section (2) and a second end (6) adjacent said shaft section (2), a number of teeth (7) distributed in circumferential direction around said axis (3), a bottom curve (9) between adjacent teeth (7), and an outer tooth curve (12), said bottom curve (9) having a positive slope from said first end (5) towards said shaft section (2) and a negative slope (14) at said second end (6). In such a shaft wear should be made as small as possible. To this end said bottom curve (9) comprises a section having a concave bottom curvature (15) between said positive slope and said negative slope.

A hydraulic machine (1) such as a pump or motor includes a working section (6) such as a gerotor. A spool (3) is rotatable about an axis (4) within a bore of the machine housing (2). The spool includes hydraulic fluid directing passages that enable operation of the machine. The spool includes first and second axially spaced apart circumferential grooves (14, 15). A plurality of first axial grooves (16) extend in intersecting relation with the first circumferential groove and a plurality of second axial grooves (17) extend in intersecting relation with the second circumferential groove. The first and second axial grooves are arranged in alternating relation about the circumference of the spool. The circumferential grooves are bounded radially inwardly by respective bottom walls (19, 22) that have a greater radial distance from the axis with axial proximity to the intersecting grooves.

A hydraulic motor includes a rotor and a stator, wherein the rotor and the stator define a plurality of motor pockets for receiving a flow of hydraulic fluid, and the rotor rotates relative to the stator based on a pressure differential between the motor pockets. A commutator having porting controls the flow of hydraulic fluid into the motor pockets. The rotor rotates about a first axis and the stator orbits about a second axis, and the stator is configured to orbit such that the second axis orbits about the first axis. The commutator is eccentrically piloted about the first axis and the second axis so that the commutator both rotates and orbits to control the flow of hydraulic fluid into the motor pockets. With such configuration, an output shaft is driven by rotation of the rotor about the first axis without orbiting, obviating the need for a drive link.

The movement of the moving gear meshed with the fixed gear in the casing changes the meshing width of the two gears, thereby changing the discharge amount of the pump. By installing a gear block inside the fixed gear, which is an internal gear, and a gear ring and gear ring cover on the outside of the moving gear, the fluid between the two gears is prevented from leaking to the outside. The fluid can pass between the two gears from or to the outside through the fluid holes in the fixed gear and the fluid inlets in the pumping chamber in the casing. The part of the fixed gear that is not engaged with the moving gear can be used as a hydraulic chamber.