Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the input shaft is located between a first and second parallel planes located at respective ends of the motor shaft and the longitudinal axis of the motor shaft is located between a third and fourth parallel planes located at respective ends of the pump shaft.

Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the input shaft is located between a first and second parallel planes located at respective ends of the motor shaft and the longitudinal axis of the motor shaft is located between a third and fourth parallel planes located at respective ends of the pump shaft.

Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the input shaft is located between a first and second parallel planes located at respective ends of the motor shaft and the longitudinal axis of the motor shaft is located between a third and fourth parallel planes located at respective ends of the pump shaft.

Abstract: A fixed displacement pump includes a housing having a cavity, an inlet, and an end cap with alignment portions therein. A cam ring pivotally associated within the cavity includes adjustment portions. The cam ring is aligned in a fixed position via a pin inserted through both a select adjustment portion and a corresponding alignment portion. The adjustment portion selected determines both rotational direction and displacement of the pump. The cam ring also includes recesses positioned adjacent the inlet to facilitate porting of fluid through the pump. A rotor mounted within the cam ring includes roller slots having groove segments. The groove segments are positioned in an arcuate arrangement about the rotor to facilitate porting of fluid through the pump. The rotor also includes undercut portions positioned between the roller slots in an arcuate arrangement on an outer edge of the rotor to facilitate porting of fluid through the pump.

Abstract: A fixed displacement pump includes a housing having a cavity, an inlet, and an end cap with alignment portions therein. A cam ring pivotally associated within the cavity includes adjustment portions. The cam ring is aligned in a fixed position via a pin inserted through both a select adjustment portion and a corresponding alignment portion. The adjustment portion selected determines both rotational direction and displacement of the pump. The cam ring also includes recesses positioned adjacent the inlet to facilitate porting of fluid through the pump. A rotor mounted within the cam ring includes roller slots having groove segments. The groove segments are positioned in an arcuate arrangement about the rotor to facilitate porting of fluid through the pump. The rotor also includes undercut portions positioned between the roller slots in an arcuate arrangement on an outer edge of the rotor to facilitate porting of fluid through the pump.

Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the input shaft is located between a first and second parallel planes located at respective ends of the motor shaft and the longitudinal axis of the motor shaft is located between a third and fourth parallel planes located at respective ends of the pump shaft.

Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the input shaft is located between a first and second parallel planes located at respective ends of the motor shaft and the longitudinal axis of the motor shaft is located between a third and fourth parallel planes located at respective ends of the pump shaft.

Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the output motor shaft is located between the longitudinal axis of the pump input shaft and the longitudinal axis of the output axles.

Abstract: An axle driving apparatus comprising a housing being defined by two separable elements joined together along a parting plane; the housing rotatably supporting a pair of axle shafts, each of the axle shafts having a longitudinal axis; the parting plane of the housing being parallel to the longitudinal axes of the axle shafts; and a hydrostatic transmission disposed in the housing and including a pump, a motor, and a member having pump and motor mounting surfaces thereon.

Abstract: An axle assembly has a housing. A hydrostatic transmission separate from the housing is mounted therein. Horizontal axle shafts are rotatably supported in the housing. The hydrostatic transmission includes a center section separate from the housing with fluid conduits connected to hydrostatic rotatable cylinder blocks. A drive shaft extends from one of the blocks and is operatively connected to the axle shafts. Check valves are associated with the conduits to affect fluid flow and are positioned to move in a vertical path at right angles to the axle shafts.

Abstract: A center section for separate mounting within the housing of an integrated transaxle comprising, a member having first and second hydrostatic unit mounting surfaces thereon, at least a pair of fluid ports in each of the mounting surfaces, and internal passageways in the member connecting at least one of the fluid ports on one of the mounting surfaces with at least one of the fluid ports on the other of the mounting surfaces.

Abstract: A reduced oil volume piston assembly for a hydrostatic unit includes a piston assembly having a piston body and a stem formed separately from the piston body. A cavity is formed in one end of the piston body. The stem includes an enlarged head and an elongated neck extending upwardly from the head. The neck lossely inserts into the cavity of the piston body so as to at least partially fill the cavity. The head is unattached to the piston body and cannot enter the cavity, but its shape allows fluid flow into the cavity around the stem. These components can be incorporated into the cylinder block assembly as separate components or the stems can be integrally cast with the cylinder block or attached thereto as a stem ring assembly.

Abstract: A brake design for a hydrostatic transaxle having a center section mounted in the transaxle housing and a pump and motor mounted on the center section. A disk brake assembly having at least one rotor is connected to the motor shaft and is entirely mounted in the housing. The design may also include a rotatable actuator mounted in the housing and extending therefrom for engaging the brake assembly.

Abstract: An improved compact design for a hydrostatic transmission having a hydraulic pump and hydraulic motor mounted on a center section in a housing, wherein the pump and motor are mounted at generally right angles to one another, and the longitudinal axis of the input shaft is located between a first and second parallel planes located at respective ends of the motor shaft and the longitudinal axis of the motor shaft is located between a third and fourth parallel planes located at respective ends of the pump shaft.

Abstract: A differential gear design is provided for use in a vehicle, where the planet gears are mounted in openings formed in a ring or bull gear. The planet gears are engaged to and drive bevel gears, which are engaged to output axle shafts to transfer power thereto. The ring gear openings support the planet gears in the direction of their axis of rotation so as to eliminate the need for a cross shaft which would engage and support the planet gears.

Abstract: An improved hydrostatic transmission having means for hydraulically bypassing the hydrostatic transmission, and the method for bypassing the hydrostatic porting to enable free wheeling of the vehicle. The bypass in one embodiment includes a plate or similar member and a rotatable lever or arm for engaging the plate to lift a hydrostatic pump or motor from its running urface in the hydrostatic transmission.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

Abstract: A filled hydraulic piston assembly includes a piston body having first and second ends and a compartment in the piston body extending inwardly from the second end toward the first end. The piston is filled with an insert element which is inserted into the compartment of the piston and then held therein by pushing an annular lip on the second end of the body inwardly and against the adjacent end of the insert element. The insert element is comprised of a material that is less dense than the material of the body but has a higher bulk modulus than hydraulic oil. Oil channels can be formed in a variety of shapes on or around the insert so that oil may flow through the filled piston. The piston insert element can be formed from a variety of materials, such as plastic, magnesium, aluminum or other nonferrous metals. The body is generally comprised of steel.

Abstract: A hydrostatic transmission having a hydraulic pump and motor for use in a vehicle, including a center section for mounting and operatively connecting the pump and motor, a rotatable output drive shaft engaged to the hydraulic motor, and a running surface and support members integrally formed with the center section to fully support the output drive shaft, and further including a thrust bearing mounted in a housing for the transmission to engage said hydraulic motor, where the thrust bearing is supported by the upper and lower casing sections of the housing.

Abstract: An integrated hydrostatic transmission has a housing comprised of two separable elements detachably joined together along a substantially horizontal parting plane. A hydrostatic transmission including a hydrostatic pump, a hydrostatic motor, and a center section is separately mounted within the housing. The center section comprises a generally L-shaped member having a hydrostatic pump and motor mounting surfaces thereon disposed at right angles to each other. A pair of fluid ports is on each of the mounting surfaces, and internal passageways are in the L-shaped member connecting each of the fluid ports on one of the mounting surfaces with one of said fluid ports being on the other of the mounting surfaces. The L-shaped member comprises first and second legs integrally joined and extending at right angles to each other, with the first leg normally extending in a horizontal direction, and the second leg normally extending in a vertical direction.