# US 8,464,599 B2 · Eight 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 8,464,599 B2 - Document ID: US8464599B2 - Status: Granted - Kind: B2 - Application number: 12/987,809 - Filed: 2011-01-10 - Published: 2012-07-12 - Granted: 2013-06-18 - Earliest claimed: 2011-01-10 - Assignees: GM Global Technology Operations LLC - Applicants: Craig S. Ross; Edward W. Mellet; Scott H. Wittkopp - Inventors: Craig S. Ross; Edward W. Mellet; Scott H. Wittkopp - Web page: https://patentgrep.com/patent/US8464599B2 ## CPC - F16H 3/006: {power being selectively transmitted by parallel flow paths, e.g. dual clutch transmissions} - 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 - Y10T 74/19065: Aligned - Y10T 74/19228: Multiple concentric clutch shafts - Y10T 74/19233: Plurality of counter shafts - Y10T 74/19242: Combined gear and clutch - F16H: GEARING - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A transmission is connectable to an input member and includes an output transfer gear, first and second shaft members, first and second countershaft members, a plurality of co-planar gear sets, and a plurality of torque transmitting devices. The torque transmitting devices include a plurality of gears, 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, 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, fourth, fifth and sixth gear set, wherein the first gear set includes a first gear in mesh with a second gear and a 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, the fourth gear set includes a first gear in mesh with a second gear, the fifth gear set includes a first gear in mesh with a third gear, wherein the third gear is in mesh with a second gear and the sixth gear set includes a first gear in mesh with a second gear and a third gear; a first transmission input member rotatably supported in the transmission housing and wherein each of the first gears of the third, fourth, fifth and sixth gear sets 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 each of the first gears of the first and second gear sets 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 surrounds the first transmission input member and wherein the selective engagement of the second clutch of the dual clutch assembly transfers torque form 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 third gear of the first gear set, the third gear of the second gear set and the third gear of the sixth gear set are each selectively connectable for common rotation with the first countershaft, and wherein the third gear of the fifth gear set is supported for free rotation on 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 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, the second gear of the fifth gear set and the second gear of the sixth gear set are each selectively connectable for common rotation with the second countershaft; and five synchronizer assemblies 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 first countershaft and the second countershaft, 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 eight forward speed ratios. ### Claim 2 (depends on 1) The transmission of claim 1 wherein a first of the five synchronizer assemblies selectively connects at least one of the second gear of the first gear set and the second gear of the second gear set to the second countershaft. ### Claim 3 (depends on 2) The transmission of claim 2 wherein a second of the five synchronizer assemblies selectively connects at least one of the third gear of the first gear set and third gear of the second gear set to the first countershaft. ### Claim 4 (depends on 3) The transmission of claim 3 wherein a third of the five synchronizer assemblies selectively connects at least one of the second gear of the third gear set and the second gear of the fourth gear set to the second countershaft. ### Claim 5 (depends on 4) The transmission of claim 4 wherein a fourth of the five synchronizer assemblies selectively connects at least one of the second gear of the fifth gear set and second gear of the sixth 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 third gear of the sixth gear set to the first countershaft. ### Claim 7 (depends on 1) The transmission of claim 1 wherein the first gear set is adjacent the dual clutch assembly, 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 disposed between the fifth gear set and an end wall of the transmission housing. ### Claim 8 (depends on 7) The transmission of claim 7 wherein the five synchronizer assemblies includes a first synchronizer assembly for selectively connecting the second gear of the first gear set to the second countershaft to establish a second gear ratio when the second clutch of the dual clutch is engaged to connect the dual clutch housing to the second transmission input member. ### Claim 9 (depends on 8) The transmission of claim 8 wherein the five synchronizer assemblies includes a first synchronizer assembly for selectively connecting the second gear of the second gear set to the second countershaft to establish a sixth gear ratio when the second clutch of the dual clutch is engaged to connect the dual clutch housing to the second transmission input member. ### Claim 10 (depends on 9) The transmission of claim 9 wherein the five synchronizer assemblies includes a second synchronizer assembly for selectively connecting the third gear of the first gear set to the first countershaft to establish a fourth gear ratio when the second clutch of the dual clutch is engaged to connect the dual clutch housing to the second transmission input member. ### Claim 11 (depends on 10) The transmission of claim 10 wherein the five synchronizer assemblies includes a second synchronizer assembly for selectively connecting the third gear of the second gear set to the first countershaft to establish an eighth gear ratio when the second clutch of the dual clutch is engaged to connect the dual clutch housing to the second transmission input member. ### Claim 12 (depends on 11) The transmission of claim 11 wherein the five synchronizer assemblies includes a third synchronizer assembly for selectively connecting the second gear of the third gear set to the second countershaft to establish a first gear ratio when the first clutch of the dual clutch is engaged to connect the dual clutch housing to the first transmission input member. ### Claim 13 (depends on 12) The transmission of claim 12 wherein the five synchronizer assemblies includes a third synchronizer assembly for selectively connecting the second gear of the fourth gear set to the second countershaft to establish a third gear ratio when the first clutch of the dual clutch is engaged to connect the dual clutch housing to the first transmission input member. ### Claim 14 (depends on 13) The transmission of claim 13 wherein the five synchronizer assemblies includes a fourth synchronizer assembly for selectively connecting the second gear of the fifth gear set to the second countershaft to establish a reverse gear ratio when the first clutch of the dual clutch is engaged to connect the dual clutch housing to the first transmission input member. ### Claim 15 (depends on 14) The transmission of claim 14 wherein the five synchronizer assemblies includes a fourth synchronizer assembly for selectively connecting the second gear of the sixth gear set to the second countershaft to establish a fifth gear ratio when the first clutch of the dual clutch is engaged to connect the dual clutch housing to the first transmission input member. ### Claim 16 (depends on 15) The transmission of claim 15 wherein the five synchronizer assemblies includes a fifth synchronizer assembly for selectively connecting the third gear of the sixth gear set to the first countershaft to establish a seventh gear ratio when the first clutch of the dual clutch is engaged to connect the dual clutch housing to the first transmission input member. ### Claim 17 (depends on 1) The transmission of claim 1 further comprising a first countershaft transfer gear fixed to the first countershaft for common rotation with the first countershaft and a second countershaft transfer gear fixed to the second countershaft for common rotation with the second countershaft and wherein the first and second countershaft transfer gears transfer torque from at least one of the first and second countershafts to a transmission output member. ### Claim 18 (depends on 17) The transmission of claim 17 wherein the transmission output member is a gear that meshes with the each of the first and second countershaft transfer gears. ### Claim 19 A transmission comprising: a transmission housing; a dual clutch assembly having a first clutch, 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, fourth, fifth and sixth gear set, wherein the first gear set includes a first gear in mesh with a second gear and a 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, the fourth gear set includes a first gear in mesh with a second gear, the fifth gear set includes a first gear in mesh with a third gear, wherein the third gear is in mesh with a second gear and the sixth gear set includes a first gear in mesh with a second gear and a third gear; a first transmission input member rotatably supported in the transmission housing and wherein each of the first gears of the third, fourth, fifth and sixth gear sets 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 each of the first gears of the first and second gear sets 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 surrounds the first transmission input member and wherein the selective engagement of the second clutch of the dual clutch assembly transfers torque form 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 third gear of the first gear set, the third gear of the second gear set and the third gear of the sixth gear set are each selectively connectable for common rotation with the first countershaft, and wherein the third gear of the fifth gear set is supported for free rotation on 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 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, the second gear of the fifth gear set and the second gear of the sixth gear set are each selectively connectable for common rotation with the second countershaft; a first synchronizer assembly selectively connects at least one of the second gear of the first gear set and the second gear of the second gear set to the second countershaft; a second synchronizer assembly selectively connects at least one of the third gear of the first gear set and third gear of the second gear set to the first countershaft; a third synchronizer assembly selectively connects at least one of the second gear of the third gear set and the second gear of the fourth gear set to the second countershaft; a fourth synchronizer assembly selectively connects at least one of the second gear of the fifth gear set and second gear of the sixth gear set to the second countershaft; a fifth synchronizer assembly selectively connects the third gear of the sixth gear set to the first countershaft; and a first countershaft transfer gear fixed to the first countershaft for common rotation with the first countershaft and a second countershaft transfer gear fixed to the second countershaft for common rotation with the second countershaft and wherein the first and second countershaft transfer gears transfer torque from at least one of the first and second countershafts to a transmission output member, and wherein the selective engagement of the first and second clutches of the dual clutch assembly and the selective engagement of at least one of the synchronizer assemblies establishes at least one of eight forward speed ratios between the at least one of the first and the second transmission input members and the transmission output member.