Tecumseh Products Company

Unipat Ag

Norman E Jolliff

Richard T Ruebusch

Gordon C Dowen

Gary G Twaddle

Roland L Von Kaler

Frederick Paul Eberle

Kevin J Johnson

Vance E Coble

George Duncan Arnold

Dale I Havens

Orville R McDonner

Michael P Weirich

Joseph V Miller

Orville R Mcdonner

A method of manufacturing a plurality of left hand control hydrostatic transaxles and a plurality of right hand controlled hydrostatic transaxles. The method includes the steps of: providing a plurality of substantially identical axle modules; providing a plurality of left hand controlled hydrostatic transmission modules adapted to connect to respective axle modules to form left hand controlled hydrostatic transaxles, and a plurality of right hand controlled hydrostatic transmission modules adapted to connect to respective axle modules to form right hand controlled hydrostatic transaxles; attaching the plurality of left hand controlled hydrostatic transmission modules to a first quantity of the plurality of substantially identical axle modules to form a plurality of left hand controlled hydrostatic transaxles; and attaching the plurality of right hand controlled hydrostatic transmission modules to a second quantity of the plurality of substantially identical axle modules to form a plurality of right hand controlled hydrostatic transaxles. In one form of the invention, the transmission module is aligned with the axle module by piloting the output means of the motor of a hydrostatic transmission module to the input drive of a reduction gear train of the transmission module.

Method for manufacturing transaxles

A modular hydrostatic transaxle includes an axle module removably connected to a hydrostatic transmission module. The axle module includes a differential connected to a reduction gear train and disposed in an axle casing. A pair of axles are connected to the differential and supported within the axle casing. The hydrostatic transmission module comprises a transmission casing separate from the axle casing. The hydraulic motor output connection includes a shaft piloted to an input drive of the reduction gear train, which constitutes the alignment mechanism of the transmission and axle modules. A portion of the pump and motor block forms an inclined surface which supports a face of a thrust bearing. At least one homogeneous low friction bearing strip is confined between the swash plate and the interior portion of the casing. A disconnect mechanism includes a spring that urges a sleeve to engage the output and input shafts.

Hydrostatic transaxle having axial piston motor and method for manufacturing transaxles

A hydrostatic transaxle including first and second hydrostatic transmission modules and an axle drive housing. Each module includes a transmission housing, a rotating fluid pump and a rotatable fluid motor with the pump being of variable displacement and the motor being rotated at various speeds and in forward and reverse directions in response to changes in pump displacement. The axle drive housing contains first and second gear trains and a pair of axles. One of the axles is operably coupled to the first transmission module motor through the first gear train, and the other of the axles is operably coupled to the second transmission module motor through the second gear train. Each of the hydrostatic transmission module housings is detachably fixed to the axle drive housing.

Modular hydrostatic transaxle for zero turn radius mower

An implement having an engine and a transaxle which may be rigidly and directly attached to one another in a vertically stacked orientation to form an engine and transaxle module. The implement also includes ground engaging wheels attached to the transaxle axles, a handle allowing control of the implement, and one of a plurality of interchangeable working devices attached to the engine and transaxle module. For example, the implement may be a snow thrower having an auger assembly which is operatively coupled to one of the engine and the transaxle. The transaxle may include a pair of axially aligned axles which are selectively coupled together, such that when the axles are coupled together, the wheels are rotatably fixed together, and when the axles are not coupled together, the wheels are free to rotate relative to each other. The transaxle may further include a pair of housing portions, at least one housing portion having a pair of recesses in which a pair of bushings are respectively disposed, each bushing supporting an end of each of a pair of shafts of the reduction gearing of the transaxle.

Implement having engine and transaxle module

A neutral brake system for use in a hydrostatic transmission to automatically apply a brake when the hydrostatic transmission is shifted to neutral. The neutral brake system includes a hydraulically-released, spring-activated brake mechanism in direct fluid communication with the main hydraulic passages which form a hydraulic circuit between the pump and the motor. When the hydrostatic transmission is shifted to neutral, a brake spring biases a brake lever into contact with a pair of friction pads to engage a brake disk splined to the output shaft of the motor to stop the vehicle. When the hydrostatic transmission is shifted out of neutral, a charge of hydraulic pressure within the hydraulic circuit causes a piston within a brake release chamber to override the biasing force of the brake spring, and to urge the brake lever out of contact with the friction pads such that the friction pads are disengaged from the brake disk, and the output shaft of the output shaft of the motor may freely rotate. A throttling orifice is provided in the hydraulic circuit to restrict hydraulic flow from the brake release chamber to prevent abrupt engaging of the brake mechanism when the transmission is shifted to neutral.

Neutral brake

A self adjusting wet brake positioned interior of a transaxle or transmission casing. The self adjusting brake assembly utilizes a brake pad having a cooperating ramp surface which is contacted by a brake cam for brake actuation. The cooperating ramp surface allows the brake mechanism of the current invention to automatically account for brake pad wear and the attendant decrease in brake pad thickness. As the brake pad wears and decreases in thickness, the brake cam progressively contacts ramp surface of the brake pad to effect brake actuation. In one exemplary embodiment, the ramp surface is integral with the brake pad.

Self adjusting wet brake for use with a transmission or transaxle

A modular hydrostatic transaxle includes an axle module removably connected to a hydrostatic transmission module. The axle module includes a differential connected to a reduction gear train and disposed in an axle casing. A pair of axles are connected to the differential and supported within the axle casing. The hydrostatic transmission module comprises a transmission casing separate from the axle casing and hydraulically connected pump and motor disposed in the transmission casing. The motor output connection includes a shaft piloted to an input drive of the reduction gear train, which constitutes the alignment mechanism of the transmission and axle modules. The pump and motor cylinder barrels are hydraulically connected through the pump and motor block at 90&deg; orientation, and a portion of the pump and motor block forms an inclined surface which supports a face of a thrust bearing. At least one homogeneous low friction bearing strip is confined between the swash plate and the interior portion of the casing. A disconnect mechanism includes a spring that urges a sleeve to engage the output and input shafts. The brake disc is disposed on a distal end of the output shaft and a brake cover is fastened to the outer portion of the axle casing and substantially encloses the brake disc.

A variable displacement hydraulic pump includes a pump cylinder barrel having a plurality of axially arranged cylinder chambers disposed therein and each cylinder chamber includes a reciprocating piston therein. The pump is rotatably supported by the pump block and a motor block is separable from and connected to the pump block. A hydraulic motor is rotatably supported by the motor block and hydraulically connected to the pump through a pair of continuous passages formed in the pump and motor blocks. The motor includes an axis of rotation substantially perpendicular to an axis of rotation of the pump. A motor includes a cylinder barrel having a plurality of axially arranged cylinder chambers disposed therein and each cylinder chamber has a reciprocating piston therein. A thrust bearing is supported by a portion of the pump and motor block and is receivably engaged with the pistons extended from the cylinder barrel of the motor. A stop member is attached to the portion of the pump and motor block and in contact with the thrust bearing wherein relative movement of the thrust member is restrained by the stop member.

Hydrostatic transmission having two-piece pump and motor block assembly

A fully integrated hydrostatic transaxle formed of three housing members, a hydrostatic transmission and axle housing member joined to a differential housing member along a vertical plane and joined to a hydrostatic transmission mounting plate and cover member along a horizontal plane. A hydrostatic transmission is connected to and suspended from the mounting plate and cover member. In a second embodiment, a hydrostatic transmission is mounted to a hydrostatic transmission and axle housing member, which in turn is fastened to a center housing member. The center housing member is in turn connected to an axle and differential housing member. The interfaces defined by where the housing members are joined together define substantially parallel vertical planes. Means for effectively unlocking the transmission and the differential is provided so that the operator can push the vehicle without encountering the resistance of back driving the hydrostatic transmission. A neutral position adjustment mechanism provides a tactile indication of the neutral position, and the mechanism can be readjusted to define the correct neutral position.

Hydrostatic transaxle having a casing split along one or more vertical

A variable speed transmission including a rotatable input member connectable to a drive source, a pump for pumping fluid through a conduit, a gear train including an epicyclic gear train operatively coupled to the input member and the pump, and a rotatable output member selectively operatively connected to either a forward or a reverse drive gear, wherein the output member has a forward drive ratio corresponding with its connection to the forward drive gear and a different, reverse drive ratio corresponding with its connection to the reverse drive gear. The transmission may also include a pressure compensating flow metering device for regulating the pressure of fluid flowing through said conduit.

Reversible variable speed transmission and transaxle having pressure

A mechanical disconnection mechanism for a hydrostatic transmission. The output shaft of the hydrostatic transmission is divided into a drive portion and a driven portion, with both the drive portion and the driven portion being provided with external splines or gears. To connect the drive portion to the driven portion, a splined sleeve is positioned to engage the splines of both the driven portion and the drive portion such that rotation of the drive portion rotates the driven portion. To disconnect the drive portion from the driven portion, the splined sleeve is positioned to engage only one of the drive portion and the driven portion. In the disconnected position, the implement may be manually pushed without reverse driving the hydraulic unit of the transmission to thereby allow for relatively easy movement. A brake is mounted about the driven portion of the output shaft to enable the vehicle to be stopped regardless of the position of the splined sleeve.

Mechanical disconnect for a variable speed hydrostatic transmission

A variable speed, reversible transmission that utilizes two gerotor pumps for variable controlling the speed of the output shaft or axle. A rotatable input member connectable to a drive source drives first and second epicyclic gear trains, which drive the two pumps. As the fluid flow through each pump is variably restricted, the epicyclic gears associated therewith revolve about the input member, causing a worm gear intermediate the input member and the output member to variably rotate in a forward or reverse direction. The worm gear transmits rotational power from the input member to the output member in response to the fluid flow restriction through each pump. The present invention also provides for the two pumps comprising a modular pump unit and a system of transmissions employing a common modular pump assembly. Further, the present invention provides engine/transaxle modules in which the engine is mounted on the transaxle housing, and a self-propelled lawn and garden implement having a drive source which includes a variable speed transmission or transaxle which utilizes a pump for variable controlling the speed of its output shaft or axle.

Variable speed transmission and transaxle

A variable speed transmission or transaxle that utilizes a pump for variable braking of the output shaft or axle. A rotatable input shaft connectable to a drive source extends into a transmission housing and is operatively connected to a gear train that transmits rotational power to a transmission output shaft. A gerotor pump mounted within the housing utilizes a ring gear of an epicyclic gear of the gear train as an inner gerotor gear that meshes with an outer gerotor gear to pump fluid along a fluid conduit. By adjustably varying the resistance of the pump, the revolution rate of the epicyclic ring gear is adjusted which in turn results in a controlling of the speed of rotation of the transmission output shaft. In an alternate embodiment, a reversible transmission is provided by employing two gerotor pumps and two gear trains which allow forward and reverse speeds of rotation of the output shaft to be variably controlled.

Mechanical disconnect for variable speed hydrostatic transmission

A hydrostatic transaxle having a hydrostatic transmission includes a plate-like dump valve disposed between the transaxle housing or in a recess formed therein, adjacent a fluid conduit that connects the pump and motor of the transmission, the dump valve having fingers which unseat valves in the conduit to relief pressure therein. A rod having an offset portion extends through a bore in the dump valve, the rotation of the rod and offset portion urges the fingers of the plate-like dump valve towards or away from the conduit valves. The settling chamber disposed within the transmission includes protrusions upwardly projecting from the bottom of the chamber which trap particulates suspended in the hydraulic fluid that circulate through the system. A magnet is likewise disposed in the settling chamber adjacent the protrusions for attracting and holding magnetic particles and debris circulated by the hydraulic fluid. A double lip, W-shaped seal is radially provided on the output shaft connecting the transmission motor located in the transmission chamber with the gearing located in the gearing chamber that prevents hydraulic fluid and particulates from the gearing chamber to mix with the hydraulic fluid from the transmission chamber.

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Salem, IN, United States of America

Norman E Jolliff