Claims
- 1. An integrated hydrostatic transaxle comprising
a housing; a hydrostatic transmission disposed in said housing, said hydrostatic transmission comprising an axial piston pump having a rotary pump cylinder barrel, and an axial piston motor having a rotary motor cylinder barrel; an input drive shaft having a vertical axis of rotation rotatably supported in said housing and having a first portion protruding outside of said housing and a second portion protruding inside of said housing to engage said rotary pump cylinder barrel by way of spline connection for rotation at equal speed; a motor output shaft having a horizontal axis of rotation rotatably supported in said housing and said engaging said rotary motor cylinder barrel by way of spline connection for rotation at equal speed; a mechanical differential disposed in said housing; an internal bulkhead wall formed in said housing and formed substantially vertically to be disposed generally parallel to said vertical axis of rotation of said input drive shaft, said internal bulkhead wall delimiting an inner fluid reservoir surrounding said hydrostatic transmission from an inner fluid reservoir surrounding said mechanical differential such that said hydrostatic transmission is disposed one side of said internal bulkhead wall whereas said mechanical differential is disposed on the opposite side; axle shafts rotatably supported in said housing and extending outwardly from said housing, said mechanical differential drivingly connected between said motor output shaft and said axle shafts; and a fluid coupling surface disposed in a first horizontal plane inside said housing and engaging said pump cylinder barrel, said fluid coupling surface being spaced from underlying surfaces of said housing, said motor output shaft having a horizontal axis of rotation disposed in a second horizontal plane, said first horizontal plane being parallel to and not coincident with said second horizontal plane and wherein said first horizontal plane is situated nearer said first portion of said input drive shaft than said second horizontal plane.
- 2. The integrated hydrostatic transaxle according to claim 1 wherein said housing includes a lower transaxle housing element and an upper transaxle housing element joined together along a horizontal parting plane, said upper transaxle housing element including transverse channels opening on said parting plane to receive said axle shafts.
- 3. The integrated hydrostatic transaxle according to claim 2 wherein the longitudinal axis of rotation of said axle shafts is disposed parallel to said parting plane.
- 4. The integrated hydrostatic transaxle according to claim 3, and
further comprising reduction gearing disposed in said housing and residing in the same said inner fluid reservoir surrounding said mechanical differential housing, said reduction gearing drivingly connecting said motor output shaft with said mechanical differential and including a gear fixedly mounted on said motor output shaft, said motor output shaft arranged to pass through said internal bulkhead wall to connect said gear to said rotary motor cylinder barrel for rotation at equal speed.
- 5. The integrated hydrostatic transaxle according to claim 4 wherein said transverse channels communicate with said inner fluid reservoir surrounding said mechanical differential.
- 6. The integrated hydrostatic transaxle according to claim 5 wherein said lower transaxle housing element and said upper transaxle housing element once combined together substantially surround said mechanical differential, and wherein each of said axle shafts is supported in said housing by a pair of axle support locations, one of said axle support locations being disposed adjacent said mechanical differential and the other of axle support locations being positioned closer to where the respective axle shaft protrudes out from said housing.
- 7. The integrated hydrostatic transaxle according to claim 6, and further comprising a further fluid coupling surface disposed inside said housing, said further fluid coupling surface engaging with said motor cylinder barrel;
a pair of fluid passages inside said housing and hydraulically connecting said fluid coupling surface and said further fluid coupling surface together; a check valve disposed in each said pair of fluid passages and where at least one said check valve is disposed on that side of said fluid coupling surface which is furtherest away from said first portion of said input drive shaft.
- 8. The integrated hydrostatic transaxle according to claim 7 wherein said second horizontal-plane is coincident with said parting plane.
- 9. The integrated hydrostatic transaxle according to claim 8 wherein said parting plane is uniplanar.
- 10. The integrated hydrostatic transaxle according to claim 9, further comprising transverse channels in said lower housing element and opening on said parting plane for receiving said axle shafts, and wherein said longitudinal axis of said axle shafts is coincident with said parting plane.
- 11. The integrated hydrostatic transaxle according to claim 1 wherein said internal bulkhead wall fluidly segregates said inner fluid reservoir surrounding said hydrostatic transmission from said inner fluid reservoir surrounding said mechanical differential and said reduction gearing.
- 12. The integrated hydrostatic transaxle according to claim 1, wherein said internal bulkhead wall permits fluid to flow between said inner fluid reservoir surrounding said hydrostatic transmission and said inner fluid reservoir surrounding said mechanical differential and said reduction bearing.
RELATED APPLICATIONS
[0001] This application is a division of co-pending application Ser. No. 09/411,835, filed on Oct. 4, 1999, which is a division of U.S. application Ser. No. 09/112,363, filed on Jul. 9, 1998 which issued into U.S. Pat. No. 5,979,270, which claims the benefit under 35 U.S.C. §119(e) of Provisional Application No. 60/051,990, filed on Jul. 9, 1997, the entire contents of which are hereby incorporated by reference.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60051990 |
Jul 1997 |
US |
Divisions (3)
|
Number |
Date |
Country |
Parent |
09814939 |
Mar 2001 |
US |
Child |
10202066 |
Jul 2002 |
US |
Parent |
09411835 |
Oct 1999 |
US |
Child |
09814939 |
Mar 2001 |
US |
Parent |
09112363 |
Jul 1998 |
US |
Child |
09411835 |
Oct 1999 |
US |