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 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 system and method for electronically controlling the displacement of hydraulic pumps, transmissions or transaxles. A moveable swash plate is cooperable with a rotatable hydraulic pump for controlling the output thereof, and a rotatable trunnion arm is coupled to the moveable swash plate. A pair of switches may be mounted in separate locations to detect the position of a control arm used to rotate the trunnion arm. The control arm may be connected to an electronic actuation drive used to electronically control the rotatable control arm.

Abstract: A transaxle assembly having at least two transaxle housings for a zero turn or similar vehicle, where both housings mount separate hydrostatic transmissions. A mounting plate is provided to secure to both of the housings to mount the housings to a vehicle frame and if required to seal openings formed in the bottom of both of the housings. The connection plate may include tabs or other structure to secure it to the vehicle frame to increase the ease of assembly of the transaxle unit in the vehicle.

Abstract: A system and method for electronically controlling the displacement of hydraulic pumps, IHTs or HSTs. The IHT and HST includes a hydraulic transmission mounted within the casing that includes a rotatable hydraulic pump in fluid communication with a rotatable hydraulic motor and a moveable swash plate cooperable with the rotatable hydraulic pump for controlling the speed and direction of rotation of the rotatable hydraulic motor. The rotation of the hydraulic motor is used to drive an axle shaft. For controlling the positioning of the swash plate, the transaxle further includes a rotatable trunnion arm coupled to the moveable swash plate. The rotatable trunnion arm extends from the casing and is coupled to a control arm.

Abstract: A system and method for electronically controlling the displacement of hydraulic pumps, IHTs or HSTs. The IHT and HST includes a hydraulic transmission mounted within the casing that includes a rotatable hydraulic pump in fluid communication with a rotatable hydraulic motor and a moveable swash plate cooperable with the rotatable hydraulic pump for controlling the speed and direction of rotation of the rotatable hydraulic motor. The rotation of the hydraulic motor is used to drive an axle shaft. For controlling the positioning of the swash plate, the transaxle further includes a rotatable trunnion arm coupled to the moveable swash plate. The rotatable trunnion arm extends from the casing and is coupled to a control arm.

Abstract: A valve plate subjected to a nitrocarburization heat treatment process for use in a hydraulic pump, wherein the hydraulic pump includes a sump having a rotatable cylinder block located therein.

Abstract: A system and method for electronically controlling the displacement of hydraulic pumps, IHTs or HSTs. The IHT and HST includes a hydraulic transmission mounted within the casing that includes a rotatable hydraulic pump in fluid communication with a rotatable hydraulic motor and a moveable swash plate cooperable with the rotatable hydraulic pump for controlling the speed and direction of rotation of the rotatable hydraulic motor. The rotation of the hydraulic motor is used to drive an axle shaft. For controlling the positioning of the swash plate, the transaxle further includes a rotatable trunnion arm coupled to the moveable swash plate. The rotatable trunnion arm extends from the casing and is coupled to a control arm.

Abstract: In a hydrostatic transmission or integrated hydrostatic transaxle having a housing forming an oil sump and a hydraulic pump and hydraulic motor mounted in the sump and connected through hydraulic porting, a filter housing or other structure defining an internal volume is mounted adjacent to the check valves for the hydraulic porting. Oil passing into this internal volume is filtered to prevent the introduction of contaminants into the hydraulic porting. A himney is formed as part of the filter housing and extends upwards therefrom, and is open to the internal volume. The chimney also includes an opening to permit air to escape to the oil sump, to reduce the risk of air being introduced into the hydraulic porting through the check valves.

Abstract: A hydrostatic unit comprising a surface coating on a running surface. A center section or valve plate for use in a hydrostatic transmission is improved through application of the surface coating on one or both of its pump running surface and motor running surface. The end cap for a hydrostatic pump is improved in a like manner.

Abstract: A transaxle assembly having at least two transaxle housings for a zero turn or similar vehicle, where both housings mount separate hydrostatic transmissions. A mounting plate is provided to secure to the bottom of both of the housings to mount the housings to a vehicle frame and if required to seal openings formed in the bottom of both of the housings. The connection plate may include tabs or other structure to secure it to the vehicle frame to increase the ease of assembly of the transaxle unit in the vehicle.

Abstract: A dual tandem pump apparatus having a pair of coaxially arranged pump shafts and a separate input shaft that is not coaxial with the pump shafts. Charge pumps may be mounted on end caps secured to the housing or may be driven directly by the input shaft. A coupler or bevel gear arrangement is used inside the pump housing to drive the pump shafts from the input shaft.

Abstract: In a hydrostatic transmission or integrated hydrostatic transaxle having a housing forming an oil sump and a hydraulic pump and hydraulic motor mounted in the sump and connected through hydraulic porting, a filter housing or other structure defining an internal volume is mounted adjacent to the check valves for the hydraulic porting. Oil passing into this internal volume is filtered to prevent the introduction of contaminants into the hydraulic porting. A chimney is formed as part of the filter housing and extends upwards therefrom, and is open to the internal volume. The chimney also includes an opening to permit air to escape to the oil sump, to reduce the risk of air being introduced into the hydraulic porting through the check valves.

Abstract: A transaxle assembly having at least two transaxle housings for a zero turn or similar vehicle, where both housings mount separate hydrostatic transmissions. A mounting plate is provided to secure to the bottom of both of the housings to mount the housings to a vehicle frame and if required to seal openings formed in the bottom of both of the housings. The connection plate may include tabs or other structure to secure it to the vehicle frame to increase the ease of assembly of the transaxle unit in the vehicle.

Abstract: A transaxle assembly having at least two transaxle housings for a zero turn or similar vehicle, where both housings mount separate hydrostatic transmissions. A mounting plate is provided to secure to the bottom of both of the housings to mount the housings to a vehicle frame and if required to seal openings formed in the bottom of both of the housings. The connection plate may include tabs or other structure to secure it to the vehicle frame to increase the ease of assembly of the transaxle unit in the vehicle.

Abstract: A hydrostatic transmission design incorporating a unique housing shape and configuration, including a vertical split of the two casing elements, which are shaped to conform to the internal components of the transmission. The center section of the transmission has a unique configuration including a trunnion mounted swash plate, means for mounting the center section to the transmission and a motor output shaft mounted below the pump running surface. The transmission also includes an expansion chamber, preferably secured externally to the sump, having a tube mounted therein to transfer hydraulic fluid between the chamber and the sump.

Abstract: A hydrostatic transmission design incorporating a filter housing mounted adjacent to check valves in a center section. The filter housing can be secured to the center section by the check valves, which also may include high pressure bleeds to allow hydraulic fluid to flow from the hydraulic circuit. A shield may be located between the high pressure bleeds and the filter to prevent damage by the fluid to the filter as it exits the bleeds. The filter housing can also include integral projections on which a bypass actuation member can be mounted.

Abstract: A control device for hydrostatic apparatus is disclosed. One embodiment in the control device is optimized for use with a hydrostatic transmission having a casing. The control arm is movably mounted to the casing and frictional structure engages the control arm to resist rotational movement of the control arm. A spring may be used to bias a wedge into frictional relation with the control arm to resist rotation of the control arm. The wedge may also be secured with removable attachments.

Abstract: A hydrostatic transmission design incorporating a unique housing shape and configuration, including a vertical split of the two casing elements, which are shaped to conform to the internal components of the transmission. The center section of the transmission has a unique configuration including a trunnion mounted swash plate, means for mounting the center section to the transmission and a motor output shaft mounted below the pump running surface. The transmission also includes an expansion chamber, preferably secured externally to the sump, having a tube mounted therein to transfer hydraulic fluid between the chamber and the sump.

Abstract: A hydrostatic transmission design incorporating a unique housing shape and configuration, including a vertical split of the two casing elements, which are shaped to conform to the internal components of the transmission. The center section of the transmission has a unique configuration including a trunnion mounted swash plate, means for mounting the center section to the transmission and a motor output shaft mounted below the pump running surface. The transmission also includes an expansion chamber, preferably secured externally to the sump, having a tube mounted therein to transfer hydraulic fluid between the chamber and the sump.