Hydrostatic transaxle assembly and improved coupling arrangement therefor

A hydrostatic transaxle of the type including a hydrostatic transmission comprising a fluid pump including input means and a fluid motor including output means;

• an axle assembly having a differential gear means operable to transmit drive torque to first and second axle shafts;
• an output gear train operable to transmit torque from said output means of said fluid motor to said differential gear means;
• said axle assembly further having an axle housing comprising an upper casing half and a lower casing half, said casing halves being joined together on a plane containing an axis of rotation of said first and second axle shafts and being operable to journal said axle shafts therebetween;
• characterized by:
• (a) said input means of said fluid pump and said output means of said fluid motor defining a common axis of rotation;
• (b) said hydrostatic transmission further including a transmission case comprising a first case portion and a second case portion, said case portions being joined together on a plane oriented generally perpendicular to said common axis of rotation;
• (c) said first case portion including an input hub portion and said second case portion including an output hub portion, said hub portions being disposed at opposite axial ends of said hydrostatic transmission;
• (d) said axle housing casing halves including an input portion in cooperative engagement about said input hub portion, and an output portion in cooperative engagement about said output hub portion.

A hydrostatic transaxle of the type including a hydrostatic transmission having an input means, a hydrostatic pump driven by said input means, a hydrostatic motor, and an output means driven by said motor;

• and an axle assembly having a differential gear means including an input gear and first and second output gears, first and second axle shafts driven by said first and second output gears, respectively, and an output gear train operable to transmit torque from said output means of said hydrostatic transmission to said input gear of said differential gear means, said axle assembly further having an axle housing comprising an upper casing half and a lower casing half, said casing halves being joined together on a plane containing an axis of rotation of said first and second axle shafts and being operable to journal said axle shafts therebetween;
• characterized by:
• (a) said hydrostatic transmission further including a transmission case comprising a first case portion and a second case portion, said case portions being joined together on a plane oriented generally perpendicular to an axis of rotation defined by said output means;
• (b) said axle housing casing halves including a receiving portion disposed to surround said output means of said hydrostatic transmission;
• (c) another portion of said transmission case cooperating with at least one portion of said axle casing halves to define mounting means and a torque reaction means;
• and
• (d) said output means, said mounting means and said torque reaction means comprising the only portions of said transmission case fixedly secured to said axle housing.

A hydrostatic transaxle of the type including a hydrostatic transmission having an input means, a hydrostatic pump driven by said input means, a hydrostatic motor, and an output means driven by said motor;

• and an axle assembly having a differential gear means including an input gear and first and second output gears, first and second axle shafts driven by said first and second output gears, respectively, and an output gear train operable to transmit torque from said output means of said hydrostatic transmission to said input gear of said differential gear means, said axle assembly further having an axle housing comprising an upper casing half and a lower casing half, said casing halves being joined together on a plane containing an axis of rotation of said first and second axle shafts and being operable to journal said axle shafts therebetween;
• characterized by:
• (a) said hydrostatic transmission further including a transmission case comprising a first case portion and a second case portion, said case portions being joined together to define a main transmission case, and output hub portion, and at least one mounting portion extending radially outwardly from said main transmission case portion;
• (b) said axle housing casing halves including a receiving portion disposed to surround said output means of said hydrostatic transmission, and a mounting means in fixed engagement with said mounting portion of said transmission case;
• and
• (c) said surrounding relationship of said receiving portion and said output means, and said engagement of said mounting means and said mounting portion comprising substantially the only engagement of said transmission case and said axle housing.