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A hydrostatic transaxle axle assembly for a vehicle such as a grass mowing lawn or garden tractor comprising a housing for an internally disposed hydrostatic transmission having a variable-displacement hydraulic pump fluidly connected to a fixed-displacement hydraulic motor, the hydraulic motor bein

A hydrostatic transaxle axle assembly for a vehicle such as a grass mowing lawn or garden tractor comprising a housing for an internally disposed hydrostatic transmission having a variable-displacement hydraulic pump fluidly connected to a fixed-displacement hydraulic motor, the hydraulic motor being connected by differential gearing to axle shafts supported in the housing. The housing is formed by three housing members, two of which are preferably separable on a parting plane coincident with the longitudinal axes of the axle shafts. One of the housing members being provided with an opening to allow a portion of one of the other housing members to extend through, and where the extending housing member contains within its interior a number of internal fluid passages for fluidly connecting the hydraulic pump to the hydraulic motor. This construction allows for improved cooling of the power transmitting fluid flowing between the pump and motor and simplifies manufacture of the transaxle such that the bulk or all the machining operations can be carried out in only one of the three housing elements, this housing member being the smallest of the three which can be completed using a comparatively smaller sized CNC machining-center than would otherwise be the case. The two remaining housing elements may be used in an as cast or supplied condition.

대표청구항 ▼

1. A hydrostatic transmission located within a chamber formed by a surrounding housing structure provided with an input power shaft connection and an output power shaft connection and comprising a hydraulic pump coupled to said input power shaft connection and a hydraulic motor coupled to said outpu

1. A hydrostatic transmission located within a chamber formed by a surrounding housing structure provided with an input power shaft connection and an output power shaft connection and comprising a hydraulic pump coupled to said input power shaft connection and a hydraulic motor coupled to said output power shaft connection; fluid coupling surfaces provided for said hydraulic pump and said hydraulic motor respectively and each fluid coupling surface having a pair of arcuate-shaped ports; fluid power transmitting passages for hydraulically linking said hydraulic pump and said hydraulic motor together by way of connection with said arcuate-shaped ports; said hydraulic pump having a swash-plate and an adjacently disposed cylinder barrel and where said cylinder barrel can be said to reside in alocation between said input power shaft connection on the one hand and said swash-plate on the other hand, said cylinder barrel being formed with first and second end faces and containing an array of generally axially arranged cylinders, a piston disposed in each cylinder and said each cylinder terminating in a port at the first end face of said cylinder barrel, the pistons protruding from said cylinders at the second end face of said cylinder barrel to operatively connect with said swash-plate; wherein the rotating axis of said hydraulic motor can be said to be disposed and offset with respect to that fluid coupling surface engaging said cylinder barrel on said piston side of said the first end face of said cylinder barrel.