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 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 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 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: 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 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 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 hydraulic axle combination includes a housing having first and second pump chambers containing spaced, axially aligned, first and second hydrostatic pumps with respective pump shafts and input gears; first and second hydraulic motors connected with respective first and second pumps via intermediate manifold blocks thereby enabling closed-loop internal drive systems between the associated pumps and motors and forming first and second independent hydrostatic transmissions wherein the hydraulic motor output shafts serve as first and second axle shafts; an input shaft, extending between the two transmissions, includes a gear for supplying torque to and meshing perpendicularly with the pump shaft input gears and forming, therewith a T-shaped gear box, the housing optionally including: an internal sump serving as an integral combination fluid reservoir for the axle combination, at least one breather cap, a fluid filter assembly and a drain port and plug, all mounted in various housing sides.

Abstract: In a method for successively generating, on the inner peripheral surface of a ring, the individual profiles of a plurality of teeth of an internally toothed gear wheel: positioning the ring on a turntable; imparting complex motions, at a predetermined speed relationship therebetween, on the turntable; rotating a contoured grinding wheel, via both axial and radial feeding motions, as the grinding wheel enters into the inside of the ring for the tooth profile generation; keeping the tip radius of the grinding wheel at least substantially similar to the radius of the arc shape of each tooth; and continuously maintaining but a single contact line, between the grinding wheel and the ring inner peripheral surface, during the actual generation of the tooth profiles on the inner peripheral surface of the ring, with the complex motions including both, at least partially concurrent, angular and orbital movements, in the same angular direction.

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 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 housing for a motor having fluid passages integrated within. The passages include a first passage for receiving a fluid from outside the motor, a second passage for directing the fluid away from the motor, and at least one other passage from conveying the fluid to a set of components attached to the motor housing. The housing has at least one relief valve positioned within the fluid passages for diverting a portion of the fluid directly from the first passage to the second passage.

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 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: 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.