# US 10,309,489 B2 · Multi-speed dual clutch transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,489 B2 - Document ID: US10309489B2 - Status: Granted - Kind: B2 - Application number: 14/940,962 - Filed: 2015-11-13 - Published: 2017-05-18 - Granted: 2019-06-04 - Earliest claimed: 2015-11-13 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Tejinder Singh - Web page: https://patentgrep.com/patent/US10309489B2 ## CPC - F16H 3/093: with two or more countershafts - F16H 3/006: {power being selectively transmitted by parallel flow paths, e.g. dual clutch transmissions} - F16H 2003/0826: {wherein at least one gear on the input shaft, or on a countershaft is used for two different forward gear ratios} - F16H 2003/0931: {each countershaft having an output gear meshing with a single common gear on the output shaft} - F16H 2200/006: the gear ratios comprising eight forward speeds - F16H: GEARING ## Abstract A transmission is connectable to an input member and includes an output transfer gear, first and second transmission input shaft members, first, second and third countershaft members, 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 a plurality of forward speed ratios between the input member and the output member. ## Claims ### Claim 1 A transmission comprising: a transmission housing; a dual clutch assembly having a first clutch, a second clutch and a clutch housing connectable to an engine output member, wherein the clutch housing is rotationally supported within the transmission housing; a first, second, third and fourth gear set, wherein the first gear set includes a first gear, a second gear, a third gear and an idler gear, wherein the first gear is in mesh with the second gear and the second gear is in mesh with the idler gear and the idler gear is in mesh with the third gear, the second gear set includes a first gear in mesh with a second gear and a third gear, the third gear set includes a first gear in mesh with a second gear and a third gear, the fourth gear set includes a first gear, a second gear, a third gear, a fourth gear and an idler gear, wherein the first gear is in mesh with the third gear, the third gear is in mesh with fourth gear and the idler gear and the second gear is in mesh with the idler gear; a first transmission input member rotatably supported in the transmission housing and wherein the first gear of the first gear set and the first gear of the second gear set are rotatably fixed for common rotation with the first transmission input member and wherein the selective engagement of the first clutch of the dual clutch assembly transfers torque from the clutch housing to the first transmission input member; a second transmission input member rotatably supported in the transmission housing and wherein the first gear of the third gear set and the first gear of the fourth gear set are rotatably fixed for common rotation with the second transmission input member and wherein the second transmission input member is concentric with the first transmission input member and at least partially overlays the first transmission input member and wherein the selective engagement of the second clutch of the dual clutch assembly transfers torque from the clutch housing to the second transmission input member; a first countershaft rotatably supported within the transmission housing and spaced apart from and parallel with the first and second transmission input members, wherein the second gear of the first gear set, the second gear of the second gear set, the second gear of the third gear set, the second gear of the fourth gear set 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 first and second transmission input members, wherein the third gear of the first gear set, the third gear of the second gear set, the third gear of the third gear set, the third gear of the fourth gear set are each selectively connectable for common rotation with the second countershaft; a third countershaft rotatably supported within the transmission housing and spaced apart from and parallel with the first and second transmission input members, wherein the fourth gear of the fourth gear set is selectively connectable for common rotation with the third countershaft; a first countershaft transfer gear rotatable fixed to the first countershaft for common rotation with the first countershaft; a second countershaft transfer gear rotatable fixed to the second countershaft for common rotation with the second countershaft; a third countershaft transfer gear rotatable fixed to the third countershaft for common rotation with the third countershaft wherein the first, second and third countershaft transfer gears transfer torque to a transmission output member; five synchronizer assemblies for selectively coupling at least one of gears of the four gear sets with at least one of the first, second and third countershafts, and wherein the selective engagement of the first and second clutches of the dual clutch assembly interconnects the dual clutch housing with at least one of the first and the second transmission input members and the selective engagement of at least one of the five synchronizer assemblies establishes at least one of a plurality of forward and reverse speed ratios. ### Claim 2 (depends on 1) The transmission of claim 1 wherein a first of the five synchronizer assemblies selectively connects the second gear of the first gear set and the second gear of the second gear set to the first countershaft. ### Claim 3 (depends on 2) The transmission of claim 2 wherein a second of the five synchronizer assemblies selectively connects the third gear of the first gear set and the third gear of the second gear set to the second countershaft. ### Claim 4 (depends on 3) The transmission of claim 3 wherein a third of the five synchronizer assemblies selectively connects the second gear of the third gear set and the second gear of the fourth gear set to the first countershaft. ### Claim 5 (depends on 4) The transmission of claim 4 wherein a fourth of the five synchronizer assemblies selectively connects the third gear of the third gear set and the third gear of the fourth gear set to the second countershaft. ### Claim 6 (depends on 5) The transmission of claim 5 wherein a fifth of the five synchronizer assemblies selectively connects the fourth gear of the fourth gear set to the third countershaft. ### Claim 7 (depends on 1) The transmission of claim 1 wherein the second gear set further comprises a fourth gear and an idler gear, wherein the fourth gear is in mesh with the idler gear and the idler gear is in mesh with the third gear of the fourth gear set. ### Claim 8 (depends on 7) The transmission of claim 7 wherein a fifth of the five synchronizer assemblies selectively connects the fourth gear of the second gear set and the fourth gear of the fourth gear set to the third countershaft. ### Claim 9 (depends on 1) The transmission of claim 1 wherein the third gear set further comprises a fourth gear and an idler gear, wherein the fourth gear is in mesh with the idler gear and the idler gear is in mesh with the third gear of the fourth gear set. ### Claim 10 (depends on 9) The transmission of claim 9 further comprising a sixth synchronizer assembly for selectively connecting the fourth gear of the second gear set to the third countershaft. ### Claim 11 (depends on 1) The transmission of claim 1 wherein the transmission output member is a gear that meshes with the each of the first, second and third countershaft transfer gears. ### Claim 12 (depends on 1) The transmission of claim 1 wherein the fourth gear set is adjacent the dual clutch assembly, the third gear set is adjacent the fourth gear set, the second gear set is adjacent the third gear set and the first gear set is disposed between the second gear set and an end wall of the transmission housing. ### Claim 13 (depends on 1) The transmission of claim 1 wherein the selective engagement of the first and second clutches of the dual clutch assembly interconnects the dual clutch housing with at least one of the first and the second transmission input members and the selective engagement of at least one of the five synchronizer assemblies establishes eight forward speed ratios and one reverse speed ratios. ### Claim 14 (depends on 1) The transmission of claim 1 wherein the first gear set provides a first gear ratio and a third gear ratio. ### Claim 15 (depends on 1) The transmission of claim 1 wherein the second gear set provides a fifth gear ratio and a seventh gear ratio. ### Claim 16 (depends on 1) The transmission of claim 1 wherein the third gear set provides a sixth gear ratio and an eighth gear ratio. ### Claim 17 (depends on 1) The transmission of claim 1 wherein the fourth gear set provides a second gear ratio, a fourth gear ratio, and a reverse gear ratio.