Multi-Speed Transmission With Countershaft Gearing

• US 20080202266A1
• Filed: 02/22/2007
• Published: 08/28/2008
• Est. Priority Date: 02/22/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Singh, Tejinder, Sowul, Henryk, Hendrickson, James D.
• Granted Patent: US 7,610,825 B2
• Time in Patent Office: Days
• US Class Current: 74/331
• CPC Class Codes: F16H 2003/0931 each countershaft having an output gear meshing with a single common gear on the output shaft
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 3/006 power being selectively transmitted by either one of the parallel flow paths
• CPC Class Codes: F16H 3/093 with two or more countershafts
• CPC Class Codes: Y10T 74/19228 Multiple concentric clutch shafts
• CPC Class Codes: Y10T 74/19233 Plurality of counter shafts
• CPC Class Codes: Y10T 74/19288 Double clutch and interposed transmission

Abstract

A transmission is provided having a dual clutch, to achieve torque flow through a countershaft gearing arrangement. The countershaft gearing arrangement includes a plurality of co-planar gear sets having gears that are selectively connectable to a plurality of countershafts. At least one transfer gear set transfers torque from the counter shafts to an output shaft. The output shaft is connected to a final drive unit that has a final drive unit output shaft that is transverse to an input member connected at one end to a torque converter and at the other end to the dual clutch.

Claims

1. A powertrain comprising:

a transmission input member;

a power source for generating a torque in the input member;

a first intermediate shaft;

a second intermediate shaft;

a clutch selectively engagable to couple the transmission input member with one of the first and second intermediate shafts;

a first and a second countershaft;

a transmission housing having a front and rear wall for supporting the first and second intermediate shaft and the first and second countershaft;

a first set of gears connected for common rotation with the first intermediate shaft and intermeshing with a first selectable set of gears to form a first plurality of co-planar gear sets, wherein each of the gears of the first selectable set of gears is connectable for common rotation with one of the first and second countershafts for selectively transferring the torque to the countershafts when the clutch is engaged;

a second set of gears connected for common rotation with the second intermediate shaft and intermeshing with a second selectable set of gears to form a second plurality of co-planar gear sets, wherein each of the gears of the second selectable set of gears is connectable for common rotation with one of the first and second countershafts for selectively transferring the torque to one of the countershafts when the clutch is engaged;

an output shaft disposed radially outward of the second intermediate shaft; and

a first transfer gear coupled to one of the first and second countershafts for transferring torque from the first and second countershaft to the output shaft, and

wherein one of the second plurality of co-planar gear sets that produces a first and third gear ratio is adjacent the rear wall of the transmission housing.

2. The powertrain of claim 1, wherein the first set of gears further comprises two gears.

3. The powertrain of claim 1, wherein the second set of gears further comprises three gears.

4. The powertrain of claim 1, further comprising a first idler gear rotatable about a first idler axis and intermeshing with at least one of the selectable sets of gears of the first set of gears.

5. The powertrain of claim 4, further comprising a second idler gear rotatable about the idler axis and intermeshing with the first transfer gear.

6. The powertrain of claim 1, further comprising a second transfer gear connected for common rotation with one of the first and second countershafts and intermeshing with an output gear connected for common rotation with the output shaft for transferring torque from the countershaft to the output shaft.

7. The powertrain of claim 1, further comprising a plurality of synchronizers for selectively connecting the first and second set of selectable sets of gears to at least one of the countershafts.

8. The powertrain of claim 1, further comprising eight synchronizers for selectively connecting the first and second set of selectable sets of gears to at least one of the countershafts.

9. The powertrain of claim 1, further comprising a final drive unit wherein the final drive unit has an output shaft that is perpendicular to the input member.

10. The powertrain of claim 1, wherein the clutch is a dual clutch having a first hub connected to the first intermediate shaft and a second hub connected to the second intermediate shaft.

11. The powertrain of claim 10, wherein the first hub is remote from the second hub and wherein an output shaft of the final drive unit that is perpendicular to the input member is disposed between the first and second hub.

12. The powertrain of claim 1, wherein the clutch is disposed between the first and second plurality of co-planar gear sets.

13. The powertrain of claim 1, wherein the clutch is a friction clutch.

14. The powertrain of claim 1, wherein a first plurality of co-planar gear sets further comprises two co-planar gear sets.

15. The powertrain of claim 1, wherein a second plurality of co-planar gear sets further comprises three co-planar gear sets.

16. The powertrain of claim 1, wherein one of the second plurality of co-planar gear sets transfers the torque to achieve a fifth forward gear ratio.

17. The powertrain of claim 16, wherein the one of the second plurality of co-planar gear sets that transfers the torque to achieve the fifth forward gear ratio is disposed adjacent a structural wall of the housing of the powertrain.

18. The powertrain of claim 16, wherein the one of the second plurality of co-planar gear sets that achieves the fifth forward gear ratio includes a single drive gear and a single driven gear.

19. The powertrain of claim 1, wherein one of the second plurality of co-planar gear sets transfers the torque to achieve a seventh forward gear ratio.

20. The powertrain of claim 19, wherein the one of the second plurality of co-planar gear sets that achieves the seventh forward gear ratio includes a single drive gear and a single driven gear.

21. The powertrain of claim 20, wherein the one of the second plurality of co-planar gear sets that transfers the torque to achieve the seventh forward gear ratio is disposed adjacent a structural wall of the housing of the powertrain.

23. The powertrain of claim 6, wherein the first and second transfer gears are disposed in a single plane.

24. The powertrain of claim 1 wherein a first of the first plurality of co-planar gear sets include a first selectable gear and a first gear intermeshed with a second selectable gear, and wherein a second of the first plurality of co-planar gear sets include a first gear intermeshed with a first selectable gear and a second selectable gear, wherein the first gears are coupled to the first intermediate shaft, the first selectable gears are selectively connectable to the first countershaft, and the second selectable gears are selectively connectable to the second countershaft

25. The powertrain of claim 24 wherein the first selectable gears of the first and second co-planar gear sets are selectively connectable to the first countershaft by a first synchronizer assembly having a pair of synchronizers and the second selectable gears of the first and second co- planar gear sets are selectively connectable to the second countershaft by a second synchronizer assembly having a pair of synchronizers.

26. The powertrain of claim 25 wherein the first co-planar gear set includes a reverse gear rotatable about an idler axis, and wherein the reverse gear is intermeshed with the first selectable gear of the first co-planar gear set in order to provide a reverse gear ratio.

27. The powertrain of claim 26 further comprising a reverse transfer gear rotatable about the idler axis and connected for common rotation with the reverse gear, the reverse transfer gear intermeshed with the first transfer gear.

28. The powertrain of claim 27 wherein a third of the second plurality of co-planar gear sets include a first gear intermeshed with a first selectable gear and a second selectable gear, wherein the first gear is coupled to the second intermediate shaft, the first selectable gear is selectively connectable to the first countershaft, and the second selectable gear is selectively connectable to the second countershaft.

29. The powertrain of claim 28 wherein a fourth and a fifth of the second plurality of co-planar gear sets each include a first gear intermeshed with a first selectable gear, wherein the first gears are coupled to the second intermediate shaft and the first selectable gears are selectively connectable to at least one of the first and second countershafts.

30. The powertrain of claim 29 wherein the first selectable gear of the fourth co-planar gear set is selectively connectable to the first countershaft and the first selectable gear of the fifth co-planar gear set is selectively connectable to the second countershaft.

31. The powertrain of claim 30 wherein the first selectable gears of the third and fourth co-planar gear sets are selectively connectable to the first countershaft by a third synchronizer assembly having a pair of synchronizers and the second selectable gear of the third co-planar gear set and the first selectable gear of the fifth co-planar gear set are selectively connectable to the second countershaft by a fourth synchronizer assembly having a pair of synchronizers.

32. The powertrain of claim 29 wherein the first selectable gear of the fourth co-planar gear set is selectively connectable to the second countershaft and the first selectable gear of the fifth co-planar gear set is selectively connectable to the second countershaft.

33. The powertrain of claim 32 wherein the first selectable gear of the third co-planar gear set is selectively connectable to the first countershaft by a third synchronizer assembly having a single synchronizer, the second selectable gear of the third co-planar gear set and the first selectable gear of the fourth co-planar gear set are selectively connectable to the second countershaft by a fourth synchronizer assembly having a pair of synchronizers, and the first selectable gear of the fifth co-planar gear set is selectively connectable to the second countershaft by a fifth synchronizer assembly having a single synchronizer.

34. The powertrain of claim 29 wherein the first selectable gear of the fourth co-planar gear set is selectively connectable to the first countershaft and the first selectable gear of the fifth co-planar gear set is selectively connectable to the first countershaft.

35. The powertrain of claim 34 wherein the second selectable gear of the third co-planar gear set is selectively connectable to the second countershaft by a third synchronizer assembly having a single synchronizer, the first selectable gear of the third co-planar gear set and the first selectable gear of the fourth co-planar gear set are selectively connectable to the first countershaft by a fourth synchronizer assembly having a pair of synchronizers, and the first selectable gear of the fifth co-planar gear set is selectively connectable to the first countershaft by a fifth synchronizer assembly having a single synchronizer.

22. (canceled)