Quad-clutch multi-speed transmission

1. A transmission comprising:

an input member;

an output member;

a first planetary gear set having first, second and third members;

a second planetary gear set having first, second and third members wherein the second member of the first planetary gear set is connected to the second member of the second planetary gear set and the third member of the first planetary gear set is connected to the third member of the second planetary gear set;

a clutch assembly having a first, a second, a third and a fourth torque-transmitting mechanism each selectively engageable to connect the input member with a respective different one of the members of the first and second planetary gear sets;

a first intermediate shaft connected for common rotation with the first member of the first planetary gear set;

a second intermediate shaft connected for common rotation with the second members of the first and second planetary gear sets, wherein the second intermediate shaft is concentric with the first intermediate shaft;

a third intermediate shaft connected for common rotation with the third members of the first and second planetary gear sets, wherein the third intermediate shaft is concentric with the second intermediate shaft;

a first countershaft radially offset from the intermediate shafts;

a second countershaft radially offset from the intermediate shafts;

a first countershaft transfer gear connected for common rotation with the first countershaft and in communication with the output member to transfer torque from the first countershaft to the output member;

a second countershaft transfer gear connected for common rotation with the second countershaft and in communication with the output member to transfer torque from the second countershaft to the output member;

at least three co-planar intermeshing gear sets, wherein at least one of the gears of the at least three co-planar intermeshing gear sets is fixed for common rotation with at least one of the intermediate shafts; and

a plurality of synchronizers, wherein at least one of the plurality of synchronizers is selectively engagable to connect at least one of the gears of the at least three co-planar intermeshing gear sets with at least one of the first and second countershafts for common rotation therewith, thereby transferring torque from the first and second planetary gear sets to at least one of the first and second countershafts through at least one of the intermediate shafts and at least one of the sets of co-planar intermeshing gear sets.

2. The transmission of claim 1 wherein the first members of the first and second planetary gear sets are sun gears, the second members of the first and second planetary gear sets are planet carrier members and third members of the first and second planetary gear sets are ring gears.

3. The transmission of claim 2 wherein the planet carrier member of the first planetary gear set rotatably supports a set of planet gears and wherein the set of planet gears intermeshes with the sun gear and the ring gear of the first planetary gear set and the planet carrier member of the second planetary gear set rotatably supports a set of planet gears and wherein the set of planet gears intermeshes with the sun gear and the ring gear of the second planetary gear set.

4. The transmission of claim 2 wherein the first intermediate shaft is connected for common rotation with sun gear of the first planetary gear set.

5. The transmission of claim 2 wherein the second intermediate shaft is connected for common rotation with the planet carrier members of the first and second planetary gear sets.

6. The transmission of claim 2 wherein the first torque-transmitting mechanism is selectively engageable to connect the input member with the ring gears of the first and second planetary gear sets, the second torque-transmitting mechanism is selectively engageable to connect the input member with the planet carriers of the first and second planetary gear sets, the third torque-transmitting mechanism is selectively engageable to connect the input member with the sun gear of the second planetary gear set and the fourth torque-transmitting mechanism is selectively engageable to connect the input member with the sun gear of the first planetary gear set.

7. The transmission of claim 1 wherein two of the at least three co-planar intermeshing gear sets each include a first gear in mesh with a second gear.

8. The transmission of claim 7 wherein one of the at least three co-planar intermeshing gear sets includes a first gear in mesh with a second gear and a third gear.

9. The transmission of claim 8 wherein the first gear of one of the at least three co-planar intermeshing gear sets is fixedly connected to the first intermediate shaft and the first gears of the other two of the at least three co-planar intermeshing gear sets are fixedly connected to the third intermediate shaft.

10. The transmission of claim 8 wherein the second gears of two of the at least three co-planar intermeshing gear sets are selectively engageable with the first countershaft and the second gear of the remaining one of the at least three co-planar intermeshing gear sets is selectively engageable with the second countershaft.

11. The transmission of claim 1 wherein the plurality of synchronizers further includes a first synchronizer for selectively connecting a second gear of a first of the at least three co-planar intermeshing gear sets with the first countershaft.

12. The transmission of claim 11 wherein the plurality of synchronizers further includes a second synchronizer for selectively connecting a second gear of the second of the at least three co-planar intermeshing gear sets with the second countershaft.

13. The transmission of claim 12 wherein the plurality of synchronizers further includes a third synchronizer for selectively connecting a second gear of a third of the at least three co-planar intermeshing gear sets with the first countershaft.

14. The transmission of claim 13 wherein the plurality of synchronizers further includes a fourth synchronizer for selectively connecting a third gear of the third of the at least three co-planar intermeshing gear sets with the second countershaft.

15. The transmission of claim 14 wherein the plurality of synchronizers further comprises a brake for selectively connecting the carrier members of the first and second planetary gear sets with a stationary member.

16. The transmission of claim 1 wherein the output member further includes an output transfer gear in mesh with each of the first and second countershaft transfer gears.

17. A transmission comprising:

an input member;

an output member;

a first planetary gear set having a sun gear, a carrier member and ring gear, wherein the carrier member rotatably supports a set of planet pinion gears that intermesh with both the sun gear and the ring gear of the first planetary gear set;

a second planetary gear set having a sun gear, a carrier member and a ring gear, wherein the carrier member of the second planetary gear set rotatably supports a set of planet pinion gears that intermesh with both the sun gear and the ring gear of the second planetary gear set and wherein the carrier member of the first planetary gear set is connected to the carrier member of the second planetary gear set and the ring gear of the first planetary gear set is connected to the ring gear of the second planetary gear set and wherein the carrier;

a clutch assembly having a first, a second, a third and a fourth clutch, wherein the first clutch is selectively engageable to connect the input member with the ring gears of the first and second planetary gear sets, the second clutch is selectively engageable to connect the input member with the carrier members of the first and second planetary gear sets, the third clutch is selectively engageable to connect the input member with the sun gear of the second planetary gear set and the fourth clutch is selectively engageable to connect the input member with the sun gear of the first planetary gear set;

a first intermediate shaft connected for common rotation with the sun gear of the first planetary gear set, wherein the first intermediate shaft is concentric with the input shaft;

a second intermediate shaft connected for common rotation with the carrier members of the first and second planetary gear sets, wherein the second intermediate shaft is concentric with the first intermediate shaft;

a third intermediate shaft connected for common rotation with the ring gears of the first and second planetary gear sets, wherein the third intermediate shaft is concentric with the second intermediate shaft;

a first countershaft radially offset from the intermediate shafts and in communication with the output member;

a second countershaft radially offset from the intermediate shafts and in communication with the output member;

a first, second and third co-planar intermeshing gear sets, wherein the first and second co-planar intermeshing gear sets each having a first gear intermeshing with a second gear and a third gear and the third co-planar intermeshing gear set has a first gear intermeshing with a second gear, wherein the first gears of the first and second co-planar intermeshing gear sets are fixed for common rotation with the third intermediate shaft and the first gear of the third co-planar intermeshing gear set is fixed for common rotation with the first intermediate shaft; and

a plurality of synchronizers, wherein each of the plurality of synchronizers is selectively engagable to connect at least one of the gears of the at least three co-planar intermeshing gear sets with at least one of the first and second countershafts for common rotation therewith, thereby transferring torque from the first and second planetary gear sets to at least one of the first and second countershafts through at least one of the intermediate shafts and at least one of the sets of co-planar intermeshing gear sets.

18. The transmission of claim 17 wherein the plurality of synchronizers further includes a first synchronizer for selectively connecting a second gear of a first of the at least three co-planar intermeshing gear sets with the first countershaft.

19. The transmission of claim 18 wherein the plurality of synchronizers further includes a second synchronizer for selectively connecting a second gear of the second of the at least three co-planar intermeshing gear sets with the second countershaft.

20. The transmission of claim 19 wherein the plurality of synchronizers further includes a third synchronizer for selectively connecting a second gear of a third of the at least three co-planar intermeshing gear sets with the first countershaft.

21. The transmission of claim 20 wherein the plurality of synchronizers further includes a fourth synchronizer for selectively connecting a third gear of the third of the at least three co-planar intermeshing gear sets with the second countershaft.

22. The transmission of claim 21 wherein the plurality of synchronizers further comprises a brake for selectively connecting the carrier members of the first and second planetary gear sets with a stationary member.

23. The transmission of claim 17 further comprising first and second countershaft transfer gears, wherein the first countershaft transfer gear is rotatably fixed for common rotation with the first countershaft and the second countershaft transfer gear is rotatably fixed for common rotation with the second countershaft.

24. The transmission of claim 23 wherein the output member further includes an output transfer gear in mesh with each of the first and second countershaft transfer gears.