Variable speed transmission and transaxle

Claims

What is claimed is:

1. A self-propelled lawn and garden implement having at least two ground-engaging wheels, a rotatable blade, an engine and a variable speed transmission comprising:

a rotatable input member connectable to the engine;

a rotatable output member connectable to at least one wheel;

a gear train operatively connected to said input member and said output member for transmitting rotational power of said input member to said output member, said gear train comprising an epicyclic gear including a first gear member;

a pump for pumping a fluid through a fluid conduit, said pump including a first element disposed in a fluid engaging position within said fluid conduit, wherein said pump first element comprises said first gear member;

an adjustable valve for varying a resistance to movement of fluid within said fluid conduit between a first resistance level and a second resistance level; and

wherein said first gear member revolves at a first speed to cause rotation of said output member at a first rate when said resistance to fluid movement within said fluid conduit is at said first resistance level and said input member rotates at a drive speed, and wherein said first gear member revolves at a second speed to cause rotation of said output member at a second rate when said resistance to fluid movement within said fluid conduit is at said second resistance level and said input member rotates at said drive speed.

2. The implement of claim 1, wherein said first gear member of the transmission comprises a ring gear.

3. The implement of claim 2 wherein said pump of the transmission comprises a gerotor pump, wherein a second pump element comprises an outer gerotor gear, and wherein said ring gear comprises an inner gerotor gear in intermeshing pumping engagement with said outer gerotor gear such that relative rotation between said inner and outer gerotor gears provides a pumping action capable of pumping a flow of fluid through said fluid conduit.

4. The implement of claim 2 wherein said pump of the transmission comprises a gear pump, wherein a second pump element and said ring gear comprise first and second inner gears of said gear pump in intermeshing pumping engagement gear such that rotation of said first and second inner gears provides a pumping action capable of pumping a flow of fluid through said fluid conduit.

5. The implement of claim 2 wherein said gear train of the transmission comprises a pinion gear and at least one planet gear, said pinion gear rotatably fixed to said input member, said at least one planet gear disposed between said pinion gear and said ring gear in a manner such that said at least one planet gear is in meshing engagement with said pinion gear and said ring gear and such that rotation of said input member is capable of causing said at least one planet gear to revolve about an axis of rotation of said pinion gear at a revolution speed variably controllable by adjustment of said adjustable valve.

6. The implement of claim 5 wherein said gear train of the transmission comprises first and second power transmitting gears in meshing engagement, said at least one planet gear rotatably mounted to said first power transmitting gear whereby said first power transmitting gear serves as a rotatable planet carrier, and wherein said second power transmitting gear is rotatably fixed to said output member.

7. The implement of claim 1, wherein said input member of the transmission is connectable to the engine via a flexible torque conveying element.

8. The implement of claim 7, wherein said flexible torque conveying element is a belt.

9. A self-propelled lawn and garden implement having at least two ground-engaging wheels, a rotatable blade, an engine and a variable speed transaxle comprising:

a housing for an internally disposed gear train and an internally disposed pump for pumping fluid along a fluid conduit;

at least one axle shaft rotatably supported in said housing;

an input shaft extending into said housing;

said gear train including an epicyclic gear mechanism and drivingly connected between said input shaft and said at least one axle shaft; and

said pump connected to said gear train and operable to vary the speed of rotation of said at least one axle shaft;

wherein said epicyclic gear mechanism includes a first gear member, said first gear member disposed in a fluid engaging position in said fluid conduit.

10. The implement of claim 9 wherein said gear train of the transaxle comprises a differential, and said at least one axle shaft comprises two axle shafts connected to said differential.

11. The implement of claim 9 wherein said pump of the transaxle comprises a gerotor pump.

12. The implement of claim 11 wherein said first gear member comprises a ring gear, wherein said ring gear comprises a radial periphery with lobe-shaped teeth, and wherein said ring gear comprises an inner gerotor gear of said gerotor pump.

13. The implement of claim 9 wherein said pump of the transaxle comprises a gear pump.

14. The implement of claim 9 wherein said transaxle housing defines a sump for fluid transported through said fluid conduit.

15. The implement of claim 9 in which the transaxle further comprises a second gear train and a second pump both internally disposed within said housing, said second gear train including an epicyclic gear mechanism and drivingly connected between said input shaft and said at least one axle shaft to rotate said at least one axle shaft in a second direction opposite to a direction the other gear train rotates said at least one axle shaft, said second pump connected to said second gear train and operable to vary the speed of rotation of said at least one axle shaft in said second direction.

16. The implement of claim 15 in which the transaxle further comprises a counter shaft rotatably supported in said housing and drivingly connected to said at least one axle shaft, said counter shaft operatively connectable to each of said first and second gear trains, said counter shaft disposed parallel to said at least one axle shaft.

17. The implement of claim 9, wherein said transaxle input member is connectable to the engine via a flexible torque conveying element.

18. The implement of claim 17, wherein said flexible torque conveying element is a belt.

19. A variable speed, reversible transmission comprising:

a rotatable input member connectable to a drive source;

a output member rotatable in forward and reverse directions;

a housing;

a first pump for pumping fluid through a first conduit;

a second pump for pumping fluid through a second conduit; and

a gear train comprising a first epicyclic gear train operably connecting said input member and said first pump, a second epicyclic gear train operably connecting said input member and said second pump, and a worm gear intermediate said input member and said output member and rotatable in one of forward and reverse directions in driven response to one of said first and second epicyclic gear trains.

20. The transmission of claim 19, further comprising first and second adjustable valves, said first adjustable valve disposed along said first conduit for varying the resistance to movement of fluid within said first conduit to adjust an operational speed of said first pump, said second adjustable valve disposed along said second conduit for varying the resistance to movement of fluid within said second conduit to adjust an operational speed of said second pump, whereby speeds of rotation of said output member in said forward and reverse directions are controllable.

21. The transmission of claim 20, wherein said first and second adjustable valves comprise different recessed portions of a common control rod.

22. The transmission of claim 19, wherein said first and second pumps comprise separate gerotor pumps.

23. The transmission of claim 22, wherein said second epicyclic gear train comprises a ring gear, wherein said ring gear comprises a radial periphery with lobe-shaped teeth, and wherein said ring gear comprises an inner gerotor gear of said second pump.

24. The transmission of claim 19, wherein said first epicyclic gear train comprises a ring gear operably connecting said first epicyclic gear train with said second epicyclic gear train.

25. A variable speed, reversible transmission comprising:

a rotatable input member connectable to a drive source;

an output member rotatable in forward and reverse directions;

a housing;

a first pump for pumping fluid through a first conduit;

a second pump for pumping fluid through a second conduit; and

a gear train comprising a first epicyclic gear train operably connecting said input member and said first pump, a second epicyclic gear train operably connecting said input member and said second pump;

wherein the drive source is mounted on said housing.

26. The transmission of claim 25, further comprising first and second adjustable valves, said first adjustable valve disposed along said first conduit for varying the resistance to movement of fluid within said first conduit to adjust an operational speed of said first pump, said second adjustable valve disposed along said second conduit for varying the resistance to movement of fluid within said second conduit to adjust an operational speed of said second pump, whereby speeds of rotation of said output member in said forward and reverse directions are controllable.

27. The transmission of claim 26, wherein said first and second adjustable valves comprise different recessed portions of a common control rod.

28. The transmission of claim 25, wherein said first epicyclic gear train comprises a ring gear operably connecting said first epicyclic gear train with said second epicyclic gear train.

29. The transmission of claim 25, wherein said first and second pumps comprise separate gerotor pumps.

30. The transmission of claim 29, wherein said second epicyclic gear train comprises a ring gear, wherein said ring gear comprises a radial periphery with lobe-shaped teeth, and wherein said ring gear comprises an inner gerotor gear of said second pump.

31. At variable speed, reversible transmission comprising:

an output member rotatable in forward and reverse directions;

a housing;

a pump assembly module comprising:

a rotatable input member connectable to a drive source,

a first pump for pumping fluid through a first conduit,

a second pump for pumping fluid through a second conduit,

a first epicyclic gear train operably connecting said input member and said first pump,

a second epicyclic gear train operably connecting said input member and said second pump, and

a worm gear disposed about said input member; and

a countershaft assembly having first and second gears, said first gear intermeshed with said worm gear, said second gear connected with said output member.

32. The transmission of claim 31, further comprising first and second adjustable valves, said first adjustable valve disposed along said first conduit for varying the resistance to movement of fluid within said first conduit to adjust an operational speed of said first pump, said second adjustable valve disposed along said second conduit for varying the resistance to movement of fluid within said second conduit to adjust an operational speed of said second pump, whereby speeds of rotation of said output member in said forward and reverse directions are controllable.

33. The transmission of claim 32, wherein said first and second adjustable valves comprise different recessed portions of a common control rod.

34. The transmission of claim 31, wherein said first and second pumps comprise separate gerotor pumps.

35. The transmission of claim 34, wherein said second epicyclic gear train comprises a ring gear, wherein said ring gear comprises a radial periphery with lobe-shaped teeth, and wherein said ring gear comprises an inner gerotor gear of said second pump.

36. The transmission of claim 31 wherein said first epicyclic gear train comprises a ring gear operably connecting said first epicyclic gear train with said second epicyclic gear train.

37. A system of variable speed, reversible transmissions comprising:

a rotatable input member connectable to a drive source;

an output member rotatable in forward and reverse directions;

a housing;

a first pump for pumping fluid through a first conduit;

a second pump for pumping fluid through a second conduit;

a gear train comprising:

a first epicyclic gear train operably connecting said input member and said first pump,

a second epicyclic gear train operably connecting said input member and said second pump, said first and second epicyclic gear trains interconnected through a carrier,

a worm gear interconnected with said carrier, and

a countershaft assembly having first and second gears, said first gear intermeshed with said worm gear, said second gear connected to said output member; and

valve means disposed between said first and second pumps for restricting flow through one of said first and second conduits.

38. The transmission of claim 37, wherein said valve means comprises first and second adjustable valves, said first adjustable valve disposed along said first conduit for varying the resistance to movement of fluid within said first conduit to adjust an operational speed of said first pump, said second adjustable valve disposed along said second conduit for var