Hydro-gear Limited Partnership

Sauer Gmbh

Sauer-danfoss Inc.

Sundstrand-sauer

Sauer-sundstrand Company

Sauer-sundstrand Inc.

Alan W Johnson

Ray M Hauser

Joseph E Louis

Michael A Betz

Richard L Otto

Raymond M Hauser

Jeff L Herrin

Philip W Katzer

Kenneth J Woodshank

A charge pump is provided with two independent outlets that can satisfy the pressure requirements of both a charge circuit and an auxiliary circuit. Preferably, the charge pump is a multiple roller vane pump that has at least one inlet and two outlets independent of each other. The first outlet is in fluid communication with a charge circuit, and the second outlet is in fluid communication with an auxiliary circuit. Because the two outlets are independent of each other, the roller vane pump is able to satisfy the pressure requirements of both the charge and auxiliary circuits. Preferably, the two outlets are diametrically opposed to each other, thereby reducing the load on the driveshaft. Additionally, the roller vane pump may include a second inlet independent of the first.

Charge/auxiliary circuit for reducing power losses in hydrostatic systems

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.

Hydrostatic transmission

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.

Roller vane pump

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.

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.

Reduced oil volume piston assembly for a hydrostatic unit

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.

Brake design for a hydrostatic transaxle

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.

Differential gear mechanism

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.

Method and apparatus for improved hydrostatic transmission having bypass

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.

Rider transaxle having improved hydrostatic transmission

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.

Hydraulic piston filling

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.

Growing community of inventors

Ames, IA, United States of America

Alan W Johnson