Multi-speed transmission
View Patent ↗A transmission includes an input member, an output member, first and second transmission input shafts, first and second countershafts, a plurality of co-planar gear sets and a plurality of torque transmitting devices. The torque transmitting devices include a plurality of synchronizer assemblies and a dual clutch assembly. The transmission is operable to provide at least one reverse speed ratio and six forward speed ratios between the input member and the output member.
1. A transmission comprising:
a transmission housing;
a first, second, third, fourth, fifth and sixth gear sets, wherein each of the gear sets include a first gear in mesh with a second gear and wherein the first gear set further includes a third gear in mesh with the second gear;
a transmission input shaft member rotatably supported in the transmission housing and wherein the first gears of the first, third and fifth gear sets are rotatably fixed for common rotation with the transmission input shaft member and wherein the first gears of the second, fourth and sixth gear sets are selectively connectable for common rotation with the transmission input shaft member;
a first countershaft rotatably supported within the transmission housing and spaced apart from and parallel with the transmission input shaft member, wherein each of the second gears of the second, fourth and sixth gear sets are rotatably fixed for common rotation with the countershaft and wherein the second gears of the first, third and fifth gear sets are selectively connectable for common rotation with the first countershaft;
a second countershaft rotatably supported within the transmission housing and spaced apart from and parallel with the transmission input shaft member, wherein the third gear of the first gear set is selectively connectable for common rotation with the second countershaft; and
seven synchronizer assemblies each for selectively coupling at least one of the gears of the first, second, third, fourth, fifth and sixth gear sets with at least one of the transmission input shaft member, the first countershaft and the second countershaft, and
wherein the selective engagement of at least one of the seven synchronizer assemblies establishes at least one of six forward speed ratios and at least one reverse speed ratio.
2. The transmission of claim 1 wherein a first of the seven synchronizer assemblies selectively connects the first gear of the second gear set to the transmission input shaft member.
3. The transmission of claim 2 wherein a second of the seven synchronizer assemblies selectively connects the third gear of the first gear set to the second countershaft.
4. The transmission of claim 3 wherein a third of the seven synchronizer assemblies selectively connects the second gear of the first gear set to the first countershaft.
5. The transmission of claim 4 wherein a fourth of the seven synchronizer assemblies selectively connects the first gear of the fourth gear set to the transmission input shaft member.
6. The transmission of claim 5 wherein a fifth of the seven synchronizer assemblies selectively connects the second gear of the third gear set to the first countershaft.
7. The transmission of claim 6 wherein a sixth of the seven synchronizer assemblies selectively connects the first gear of the sixth gear set to the transmission input shaft member.
8. The transmission of claim 7 wherein a seventh of the seven synchronizer assemblies selectively connects the second gear of the fifth gear set to the first countershaft.
9. The transmission of claim 1 wherein the first gear set is adjacent a first end wall of the transmission housing, the second gear set is adjacent the first gear set, the third gear set is adjacent the second gear set, the fourth gear set is adjacent the third gear set, the fifth gear set is adjacent the fourth gear set and the sixth gear set is between a second end wall of the transmission housing and the fifth gear set.
10. The transmission of claim 9 wherein the first gear set provides a second forward speed ratio and a reverse speed ratio.
11. The transmission of claim 10 further including a first and a second transfer gear and an output gear, wherein the first transfer gear is rotatably fixed to the first countershaft and in mesh with the output gear and the second transfer gear is rotatably fixed to the second countershaft and in mesh with the output gear.
12. A transmission comprising:
a transmission housing;
a first, second, third, fourth, fifth, sixth and seventh gear sets, wherein each of the gear sets include a first gear in mesh with a second gear and wherein the first gear set further includes a third gear in mesh with the second gear;
a transmission input shaft member rotatably supported in the transmission housing and wherein the first gears of the first, third, fifth and seventh gear sets are rotatably fixed for common rotation with the transmission input shaft member and wherein the first gears of the second, fourth and sixth gear sets are selectively connectable for common rotation with the transmission input shaft member;
a first countershaft rotatably supported within the transmission housing and spaced apart from and parallel with the transmission input shaft member, wherein each of the second gears of the second, fourth and sixth gear sets are rotatably fixed for common rotation with the first countershaft and wherein the second gears of the first, third, fifth and seventh gear sets are selectively connectable for common rotation with the first countershaft;
a second countershaft rotatably supported within the transmission housing and spaced apart from and parallel with the transmission input shaft member, wherein the third gear of the first gear set is selectively connectable for common rotation with the second countershaft; and
eight synchronizer assemblies each for selectively coupling at least one of the gears of the first, second, third, fourth, fifth, sixth and seventh gear sets with at least one of the transmission input shaft member, the first countershaft and the second countershaft, and
wherein the selective engagement of at least one of the eight synchronizer assemblies establishes at least one of seven forward speed ratios and at least one reverse speed ratio.
13. The transmission of claim 12 wherein a first of the eight synchronizer assemblies selectively connects the first gear of the second gear set to the transmission input shaft member.
14. The transmission of claim 13 wherein a second of the eight synchronizer assemblies selectively connects the third gear of the first gear set to the second countershaft.
15. The transmission of claim 14 wherein a third of the eight synchronizer assemblies selectively connects the second gear of the first gear set to the first countershaft.
16. The transmission of claim 15 wherein a fourth of the eight synchronizer assemblies selectively connects the first gear of the fourth gear set to the transmission input shaft member.
17. The transmission of claim 16 wherein a fifth of the eight synchronizer assemblies selectively connects the second gear of the third gear set to the first countershaft.
18. The transmission of claim 17 wherein a sixth of the eight synchronizer assemblies selectively connects the first gear of the sixth gear set to the transmission input shaft member.
19. The transmission of claim 18 wherein a seventh of the eight synchronizer assemblies selectively connects the second gear of the fifth gear set to the first countershaft.
20. The transmission of claim 19 wherein a eighth of the eight synchronizer assemblies selectively connects the second gear of the seventh gear set to the first countershaft.