Hydrostatic transaxle having axial piston motor and method for manufacturing transaxles

Abstract

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° 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.

1 - 30 . (canceled)  
     
     
         31 . A method of aligning an axle module and a transmission module; the axle module comprising an axle casing, a differential and a reduction gear train connected to the differential, the reduction gear train including an input drive, the differential and gear train disposed in the axle casing; a pair of axles connected to the differential and supported within the axle casing; a hydrostatic transmission module comprising a transmission casing separate from the axle casing and a hydraulically connected pump and motor disposed in the transmission casing, the pump having an input driving the pump, the motor having an output means selectively drivingly connected to the reduction gear train of the axle module; the hydrostatic transmission casing removably connected to the axle casing; the method comprising: 
 piloting the motor output means to the input drive of the reduction gear train to align the transmission and axle modules.    
     
     
         32 . The method of  claim 31 , wherein the motor output means comprises an output shaft and the input drive comprises an input shaft, the output shaft defining a first surface, the input shaft defining a second surface, whereby said step of piloting the motor output means to the input drive of the reduction gear train to align the transmission and axle modules comprises coaxially engaging the first surface defined by the output shaft with the second surface defined by the input shaft.  
     
     
         33 . The method of  claim 31 , wherein the transmission casing includes a pair of diametrically opposed mounting elements disposed on an external surface thereof, and wherein the axle casing includes a respective pair of mounting elements on an external surface of the axle casing, said method further comprising: 
 mounting the transmission casing to the axle casing by securing the mounting elements of the transmission casing to the respective mounting elements of the axle casing.    
     
     
         34 . A method of aligning an axle module and a transmission module; the axle module comprising an axle casing, a differential and a reduction gear train connected to the differential, the reduction gear train including an input drive, the differential and gear train disposed in the axle casing; a pair of axles connected to the differential and supported within the axle casing; a transmission module comprising a transmission casing separate from the axle casing of the transmission having an output shaft selectively drivingly connected to the reduction gear train of the axle module; the hydrostatic transmission casing removably connected to the axle casing; the method comprising: 
 piloting the motor output shaft to the input drive of the reduction gear train to align the transmission and axle modules.    
     
     
         35 . The method of  claim 34 , wherein the input drive comprises an input shaft, the output shaft defining a first surface, the input shaft defining a second surface, whereby said step of piloting the motor output means to the input drive of the reduction gear train to align the transmission and axle modules comprises coaxially engaging the first surface defined by the output shaft with the second surface defined by the input shaft.  
     
     
         36 . The method of  claim 34 , wherein the transmission casing includes a pair of diametrically opposed mounting elements disposed on an external surface thereof, and wherein the axle casing includes a respective pair of mounting elements on an external surface of the axle casing, said method further comprising: 
 mounting the transmission casing to the axle casing by securing the mounting elements of the transmission casing to the respective mounting elements of the axle casing.