Abstract: A split discharge vane pump is disclosed having a pump body that includes an interior pumping chamber having a central axis and defining a continuous peripheral cam surface, the cam surface including four quadrantal cam segments, wherein diametrically opposed cam segments have identical cam profiles, and each cam segment defines an inlet arc, a discharge arc and two seal arcs. A rotor is mounted for axial rotation within the pumping chamber and a plurality of circumferentially spaced apart radially extending vanes are mounted for radial movement within the rotor, wherein the plurality of vanes define an equal number of circumferentially spaced apart buckets which extend between the rotor and the cam surface of the pumping chamber for carrying pressurized fluid.

Abstract: A compact, integrated hydrostatic transmission without reduction gearing wherein the pump and motor are contained within a single housing, and an output shaft extends from the housing inline with a shaft of the motor. The output shaft is directly connectable to a wheel of a vehicle. The pump and motor share a common sump within the housing in which pump and/or motor leakage is collected.

Abstract: A hydraulic vane pump includes a pump body defining an interior pumping chamber, an inlet port, and at least one discharge port. A cam ring is disposed within the interior pumping chamber and defines a continuous peripheral cam surface. A rotor is mounted for axial rotation within the interior pumping chamber. A plurality of vanes are mounted for radial movement within slots formed in the rotor. The pump includes axially opposed first and second wear disks disposed within the interior pumping chamber. The first wear disk is a floating wear disk and has an outer periphery which is positioned radially inward of the cam surface and is adapted and configured to slide axially with respect to the cam surface. The second wear disk is positioned adjacent to a second end surface of the rotor.

Abstract: A split discharge vane pump is disclosed having a pump body that includes an interior pumping chamber having a central axis and defining a continuous peripheral cam surface, the cam surface including four quadrantal cam segments, wherein diametrically opposed cam segments have identical cam profiles, and each cam segment defines an inlet arc, a discharge arc and two seal arcs. A rotor is mounted for axial rotation within the pumping chamber and a plurality of circumferentially spaced apart radially extending vanes are mounted for radial movement within the rotor, wherein the plurality of vanes define an equal number of circumferentially spaced apart buckets which extend between the rotor and the cam surface of the pumping chamber for carrying pressurized fluid.

Abstract: A split discharge vane pump is disclosed having a pump body that includes an interior pumping chamber having a central axis and defining a continuous peripheral cam surface, the cam surface including four quadrantal cam segments, wherein diametrically opposed cam segments have identical cam profiles, and each cam segment defines an inlet arc, a discharge arc and two seal arcs. A rotor is mounted for axial rotation within the pumping chamber and a plurality of circumferentially spaced apart radially extending vanes are mounted for radial movement within the rotor, wherein the plurality of vanes define an equal number of circumferentially spaced apart buckets which extend between the rotor and the cam surface of the pumping chamber for carrying pressurized fluid.

Abstract: A hydrostatic transmission including a pump and motor connected by supply and return lines. The hydrostatic transmission can be an integrated unit mountable to a vehicle frame as a unit. The motor portion of the transmission is configured to be at least partially received within a wheel to which an output shaft of the motor can be directed connected. Accordingly, the output shaft of the motor can be configured to function as a wheel axle.

Abstract: A hydrostatic transmission mountable to a frame of a vehicle for driving a left side or right side drive wheel. A motor portion of the transmission can extend outwardly from the frame and a pump portion can extend upwardly from the frame. The motor portion can be configured to be at least partially received within a wheel for direct mounting of the wheel to an output shaft of the motor. The pump portion can include an input shaft extending from a lower side thereof for connection to a prime mover, such as an internal combustion engine.

Abstract: A vane pump assembly including a cam ring having an elliptical inner bore defining a hydraulic pumping chamber, the pumping chamber having an interior camming surface. The cam ring defines ports for admitting fluid into the pumping chamber. A rotor, within the cam ring, defines a plurality of radial vane slots. A vane assembly is supported in each vane slot to define vane buckets. Each vane assembly has an end dynamic vane seal for reducing leakage between the buckets. Front and rear side plates, separated by an annular spacer, enclose the pumping chamber. The pump assembly may also include floating front and rear rotor seals for reducing radially inward leakage. Each rotor seal is disposed within a groove formed in the rotor, wherein discharge pressure urges the rotor seals axially outward from the pumping chamber to create an effective seal against the respective side plate.

Abstract: A hydrostatic transmission mountable to a frame of a vehicle for driving a left side or right side drive wheel. A motor portion of the transmission can extend outwardly from the frame and a pump portion can extend upwardly from the frame. The motor portion can be configured to be at least partially received within a wheel for direct mounting of the wheel to an output shaft of the motor. The pump portion can include an input shaft extending from a lower side thereof for connection to a prime mover, such as an internal combustion engine.

Abstract: A hydrostatic transmission mountable to a vehicle frame as a unit. The hydrostatic transmission has a nose cup to which a motor module is mounted. Passageways in an end block connect the pump element and motor module in a closed loop. The end block also has passageways for connecting a charge pump to the closed loop for supplying make-up flow thereto. An isolation plug is provided for separating flow between two intersecting passageways in the end block.

Abstract: A hydrostatic transmission including a pump and motor connected by supply and return lines. The hydrostatic transmission can be an integrated unit mountable to a vehicle frame as a unit. The motor portion of the transmission is configured to be at least partially received within a wheel to which an output shaft of the motor can be directed connected. Accordingly, the output shaft of the motor can be configured to function as a wheel axle.

Abstract: A split discharge vane pump is disclosed having a pump body that includes an interior pumping chamber having a central axis and defining a continuous peripheral cam surface, the cam surface including four quadrantal cam segments, wherein diametrically opposed cam segments have identical cam profiles, and each cam segment defines an inlet arc, a discharge arc and two seal arcs. A rotor is mounted for axial rotation within the pumping chamber and a plurality of circumferentially spaced apart radially extending vanes are mounted for radial movement within the rotor, wherein the plurality of vanes define an equal number of circumferentially spaced apart buckets which extend between the rotor and the cam surface of the pumping chamber for carrying pressurized fluid.

Abstract: A drive wheel with an integral fan mountable as a unit to a shaft of a hydraulic power unit for rotation therewith. Fan blades extending from the drive wheel circulate air when the drive wheel is rotated. One or more passageways extending through the drive wheel can be provided to allow air to flow axially therethrough to be circulated around the hydraulic unit. A fan assembly for a hydraulic power unit is also provided including a fan element and a rotatable shroud attached thereto.

Abstract: A normally engaged parking brake system for a mower that automatically disengages a parking brake when a steering arm is moved from a park position. Accordingly, the operator does not need to act to set or release the parking brake during normal operation. The system utilizes a hydraulic actuator that releases the parking brake when pressurized fluid is supplied thereto from a hydraulic pump of the mower. A manual pump, which can be configured to be operated by moving a steering arm of the mower, is provided for supplying pressurized fluid to the hydraulic actuator to release to brake in the event the hydraulic pump is not operating.

Abstract: An auxiliary pump assembly for a hydrostatic transmission that operates at a reduced pressure when the auxiliary circuit is not in use, and operates at an increased pressure when the auxiliary circuit is in use, thereby reducing the heat generated by the auxiliary pump. The auxiliary pump assembly can be used to supply low pressure makeup flow to a closed loop of a hydrostatic transmission. A combination valve including a bypass valve and a relief valve is also provided.

Abstract: A hydraulic unit including an integrated fluid cooler. The fluid cooler includes a flow-through type heat exchanger. The hydraulic unit can include a pump, a motor, or both a pump and a motor. The fluid cooler can be carried by a housing of the hydraulic unit and a fan for moving air through the fluid cooler and circulating air over at least a portion of the housing of the hydraulic unit can be interposed between the fluid cooler and the housing. The fluid cooler can also be configured to function as a fan shroud. Fluid from the hydraulic unit as well as fluid from other sources can be circulated through the fluid cooler.

Abstract: A hydrostatic transmission including a hydraulic pump, a hydraulic motor, and an external manifold surrounded by and in contact with air for connecting the hydraulic pump and a hydraulic motor. The external manifold facilitates heat transfer from hydraulic fluid flowing therein to the surrounding air. The design of the hydrostatic transmission with external manifold also allows virtually any desired relative orientation of the pump and motor to be achieved by only changing the shape of the manifold.

Abstract: A compact dual hydraulic pump unit having a low profile configuration. The inlet and outlet ports of the pumps may be located on opposite transverse sides of the unit for easy connection to adjacent motors coupled to the drive wheels of a vehicle.

Abstract: Improvements in trunnion shaft-controlled swashplate axial hydraulic piston pumps as well as hydraulic systems used in hydrostatic transmissions utilized. e.g., in zero-turn-radius (ZTR) wheeled vehicles, such as grass mowers, with one embodiment thereof pertaining to, in combination, the noted pump, devoid of any internal servo control, and a reversible power actuator, for controlling the angle of the swashplate, externally affixed to the housing containing the pump and operatively interconnected with an end of the trunnion shaft extending from the pump housing, with the power actuator being one of a rotary actuator, a fluid power axial cylinder and a rotary electronic actuator.

Abstract: A hydrostatic transmission mountable to a vehicle frame as a unit. The hydrostatic transmission has a nose cup to which a motor module is mounted. Passageways in an end block connect the pump element and motor module in a closed loop. The end block also has passageways for connecting a charge pump to the closed loop for supplying make-up flow thereto. An isolation plug is provided for separating flow between two intersecting passageways in the end block.