Hydrostatic Transaxle

An axle assembly comprising a housing having an internal chamber for an internally disposed hydrostatic transmission and forming an integral part of said hydrostatic transmission, said hydrostatic transmission comprising a variable-displacement, hydraulic pump and a fixed-displacement hydraulic motor;

• speed reducing gearing in said housing and drivingly connected to said hydraulic motor;
• a pair of axle shafts rotatably supported in said housing and a mechanical differential disposed within said housing, said differential drivingly connected between said speed reducing gearing and said pair of axle shafts;
• said housing being defined by three main housing elements and where two of said housing elements each supporting one of said pair of axle shafts are arranged to be joined together along a parting plane disposed perpendicular to the longitudinal axes of said pair of axle shafts;
• and wherein one of said two housing elements is provided with an opening for allowing a portion of the remaining housing element to extend through and where that housing element having structure fluid power transmitting passages for connecting said hydraulic pump to said hydraulic motor together.

An axle assembly comprising a surrounding housing structure providing an internal chamber for an internally disposed hydrostatic transmission and forming an integral part of said hydrostatic transmission, said hydrostatic transmission comprising a variable-displacement swash-plate hydraulic piston pump and a fixed-displacement hydraulic motor;

• speed reducing gearing disposed within said chamber and drivingly connected to said fixed-displacement hydraulic motor;
• a power output connection in the form of a pair of axle shafts rotatably supported in said housing and projecting from said housing;
• a mechanical differential disposed within said chamber and drivingly connected between said speed reducing gearing and said pair of axle shafts;
• said housing being defined by at least three separable elements of said axle assembly of which at least one includes within its internal structure a plurality of fluid power transmitting passages and an exterior heat radiating surface and where a portion of said fluid power transmitting passages lie directly adjacent to said heat radiating surface, and where two other of said at least three separable elements are each to support a respective one of said pair of axle shafts and arranged to separate about a first parting-plane disposed generally transverse to the longitudinal axes of said pair of axle shafts;
• a power input connection in the form of an input drive-shaft rotatably supported in said housing and projecting from said housing, said input drive-shaft extending inwardly to pass through that separable element provided with said fluid power transmitting passages and an exterior heat radiating surface to enter said chamber for drivingly connecting with said variable-displacement swash-plate hydraulic piston pump;
• a cooling fan disposed on said input drive-shaft external to said housing and including a plurality of blades such that during rotation of said input drive-shaft a draught of cooling air is imparted from said cooling fan towards said separable element provided with fluid power transmitting passages and an exterior heat radiating surface as well as adjoining separable elements of said axle assembly.