Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing. A brake assembly may be mounted in the port block to provide braking for the output axle or it may be located externally to the axle housing portion of the assembly. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block.

Abstract: A transaxle including a hydrostatic transmission mounted in a transmission housing and having a pair of hydraulic pumps and hydraulic motors operatively connected together through a center section mounted in the housing. First and second axle housings are mounted on opposite ends of the transmission housing, with output axles mounted in the axle housings and connected to the respective hydraulic motors, and the output axles are offset so that the axes of rotation of the axles do not intersect any portion of the transmission housing.

Abstract: A hydraulic motor assembly having a hydraulic motor mounted in a motor housing and an axle mounted in a separate axle housing. A ring gear and a port block are mounted between the motor housing and the axle housing. A swash plate is mounted in the motor housing and is engaged to the hydraulic motor to control the hydraulic output thereof, and the swash plate is movable between at least a first position and a second position.

Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block. The motor assembly may also include pressure relief valves or neutral valves in the motor port block and a brake assembly mounted in the port block or on the motor housing to provide braking for the output axle.

Abstract: A differential assembly for driving a pair of axle shafts includes a drive gear located in a housing and having at least one pair of symmetrically disposed slots formed therein. A pair of differential bushings are located in the housing on opposite sides of the drive gear. A pair of differential carriers extend through the drive gear, each carrier having its end portions engaged to notches formed in the differential bushings. The differential carriers further include a center key engaging the slots in the drive gear, whereby the carriers and bushings rotate with the drive gear. The interaction of the bushings with the carriers retains the carriers in engagement with the drive gear.

Abstract: A combination check valve and pressure relief valve is provided for use in regulating the flow of fluid between a first fluid side and a second fluid side. The valve may include a valve body, a valve insert positioned within an aperture of the valve body, a check poppet attached to the valve insert, and a check spring positioned between the valve insert and the valve body. In addition, a relief spring and a relief poppet may be positioned within a cavity formed by the valve insert and secured in position by the check poppet. The combination of the valve insert and the check poppet is adapted to move relative to the valve body and against the force of the check spring to permit fluid to pass from the first fluid side to the second fluid side, and the relief poppet is adapted to move relative to the check poppet against the force of the relief spring to allow fluid to pass from the second fluid side to the first fluid side.

Abstract: A transaxle comprised of a hydrostatic transmission mounted in a transmission housing and having a pair of hydraulic pumps and hydraulic motors operatively connected together through a center section mounted in the housing. First and second axle housings are mounted on opposite ends of the transmission housing, with output axles mounted in the axle housings and connected to the respective hydraulic motors.

Abstract: A hydraulic motor assembly having a hydraulic motor mounted in a motor housing and an axle mounted in a separate axle housing. A ring gear and a port block are mounted between the motor housing and the axle housing. A swash plate is mounted in the motor housing and is engaged to the hydraulic motor to control the hydraulic output thereof, and the swash plate is movable between at least a first position and a second position.

Abstract: A combination check valve and pressure rise rate valve is provided for regulating the flow of fluid between a first fluid side and a second fluid side. The valve may include a valve body, a valve insert positioned within an aperture of the valve body, and a check poppet attached to the valve insert. In addition, the valve may include a cylinder positioned within the valve insert, a piston slidably positioned within the cylinder, a spring positioned between the cylinder and the valve insert, and an accumulator formed between the cylinder and the piston.

Abstract: An improved diagnostic system for a hydrostatic apparatus such as a hydrostatic transmission or transaxle is disclosed. A fastener having a port formed therein is used to connect a hydraulic component such as a center section to a housing. A diagnostic system may be located external to the housing and connected to the hydraulic circuit at least partially through the fastener port. A relief valve may also be located in the fastener and connected to the fastener port, or in a different fastener having a separate fastener port, to permit the fluid in the hydraulic circuit to be discharged to a sump.

Abstract: A hydraulic drive apparatus having a center section located in a housing includes a hydraulic pump and motor disposed thereon and in fluid communication with a hydraulic porting system in the center section. The pump is driven by an input shaft extending out of the housing and the motor drives an output shaft that is generally perpendicular to the input shaft. A bypass actuator extends into the center section perpendicular to both the input shaft and the output shaft. Rotation of the bypass actuator acts to lift the hydraulic motor from the center section to break the hydraulic interface between the hydraulic motor and the hydraulic porting system. The center section may include a second pump and motor with a second hydraulic porting system and a second bypass actuator.

Abstract: An expansion sump is provided in the axle horn of a hydraulic apparatus, and a cap member seals the expansion sump from the main sump. An arcuate sealed fluid passage is provided between the periphery of the cap member and the housing. The sealed fluid passage cooperates with a first passage between the expansion sump and the sealed fluid passage and a second passage between the main sump and the sealed fluid passage to form a siphon to permit fluid communication between the two sumps. The hydraulic apparatus may also have an oil filter removably mounted on the external surface of the housing and a removable shield adjacent thereto, with an engagement member formed on the shield to prevent the oil filter from being removed from the housing with the shield in place.

Abstract: A cylinder block brake for a hydrostatic transmission or transaxle is provided. A braking member is located in a housing adjacent to a motor cylinder block and has a first position where it is not engaged to the motor cylinder block and a second, braking position where it is engaged to the motor cylinder block. A brake actuation shaft is located in the housing and has a cam portion located along its longitudinal axis. The cam portion is positioned to engage the braking member so that rotation of the brake actuation shaft moves the braking member between the engaged and disengaged positions.

Abstract: A hydraulic drive apparatus having a pair of hydraulic pumps and a pair of hydraulic motors mounted on a common center section in a housing is disclosed. Each hydraulic motor is engaged to an adjustable swash plate located in the transmission housing for adjusting the fluid displacement thereof and an actuator mechanism for adjusting the position of the swash plate. Separate axle housings are mounted on the ends of the transmission housing for housing output axles that are operatively connected to the output shafts of the respective hydraulic motors.

Abstract: In a hydrostatic device using an axial piston pump, a return plate is mounted so that it contacts the movable swash plate of the hydrostatic transmission. The plate is biased by a spring-type mechanism to force the swash plate to return to neutral, and the set position of the plate may be externally adjusted. A bias arm comprising a generally U-shaped member having spring mounted on either leg thereof may be engaged to the return plate.

Abstract: An improved diagnostic system for a hydrostatic apparatus such as a hydrostatic transmission or transaxle is disclosed. A fastener having a port formed therein is used to connect a hydraulic component such as a center section to a housing. A diagnostic system may be located external to the housing and connected to the hydraulic circuit at least partially through the fastener port. A relief valve may also be located in the fastener and connected to the fastener port, or in a different fastener having a separate fastener port, to permit the fluid in the hydraulic circuit to be discharged to a sump.

Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing having a motor sump and a gear sump. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block. A case drain comprising multiple passages permits hydraulic fluid to pass from both the motor sump and from the gear sump to an external sump.

Abstract: A transaxle comprised of a hydrostatic transmission mounted in a transmission housing and having a pair of hydraulic pumps and hydraulic motors operatively connected together through a center section mounted in the housing. First and second axle housings are mounted on opposite ends of the transmission housing, with output axles mounted in the axle housings and connected to the respective hydraulic motors.

Abstract: A combination check valve and pressure relief valve is provided for use in regulating the flow of fluid between a first fluid side and a second fluid side. The valve may include a valve body, a valve insert positioned within an aperture of the valve body, a check poppet attached to the valve insert, and a check spring positioned between the valve insert and the valve body. In addition, a relief spring and a relief poppet may be positioned within a cavity formed by the valve insert and secured in position by the check poppet. The combination of the valve insert and the check poppet is adapted to move relative to the valve body and against the force of the check spring to permit fluid to pass from the first fluid side to the second fluid side, and the relief poppet is adapted to move relative to the check poppet against the force of the relief spring to allow fluid to pass from the second fluid side to the first fluid side.

Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block. The motor assembly may also include pressure relief valves or neutral valves in the motor port block and a brake assembly mounted in the port block or on the motor housing to provide braking for the output axle.