Title of Invention	MULTI-SPEED TRANSMISSION WITH A COUNTERSHAFT GEARING ARRANGEMENT
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 first and second countershaft. A transfer gear set transfers torque from the countershaft 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.

Title of Invention

MULTI-SPEED TRANSMISSION WITH A COUNTERSHAFT GEARING ARRANGEMENT

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 first and second countershaft. A transfer gear set transfers torque from the countershaft 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.

Full Text	1 MULTI-SPEED TRANSMISSION WITH A COUNTERSHAFT GEARING ARRANGEMENT TECHNICAL FIELD [0001] The invention relates to a multi-speed transmission having a countershaft gearing arrangement. BACKGROUND [0002] A typical multi-speed, dual clutch transmission uses a combination of two friction clutches and several dog clutch/synchronizers to achieve "power- on" or dynamic shifts by alternating between one friction clutch and the other, with the synchronizers being "pre-selected" for the oncoming ratio prior to actually making the dynamic shift. "Power-on" shifting means that torque flow from the engine need not be interrupted prior to making the shift. This concept typically uses countershaft gears with a different, dedicated gear pair or set to achieve each forward speed ratio. Accordingly, the total number of gears required in this typical design is two times the number of forward speeds, plus three for reverse. This necessitates a large number of required gear pairs, especially in transmissions that have a relatively large number of forward speed ratios. SUMMARY [0003] In an aspect of the present invention, a powertrain having a transmission input member, a power source for generating a torque in the input member, a first intermediate shaft, a second intermediate shaft concentric with the first intermediate shaft, a clutch, a first countershaft, a second countershaft, first set of gears, a second set of gears, an output shaft and first and second transfer gears is provided. 2 [0004] The first countershaft is radially spaced from the second intermediate shaft. The second countershaft is radially spaced from the second intermediate shaft. The clutch is selectively cngagable to couple the transmission input member with one of the first and second intermediate shafts. The first set of gears are connected for common rotation with one of the first and second intermediate shafts and intermesh with a first selectable set of gears to form a first plurality of co-planar gear sets. Each of the gears of the first selectable set of gears is connectable for common rotation with at least one of the first and second countershafts for selectively transferring the torque to the countershafts when the clutch is engaged. [0005] The second set of gears is connected for common rotation with the other of the first and second intermediate shafts and intermeshes with a second set of gears. The second set of gears are selectively connectable for common rotation with at least one of the countershafts to form a second plurality of co-planar gear sets for selectively transferring the torque to the countershafts when the clutch is engaged. [0006] The output shaft is disposed radially outward of the second intermediate shaft. The first transfer gear is coupled to the first countershaft for transferring torque from the first countershaft to the output shaft. The second transfer gear is coupled to the second countershaft for transferring torque from the second countershaft to the output shaft. [0007] In another aspect of the present invention, a co-planar gear set that provides a first gear ratio is adjacent one of the plurality of supporting walls. [0008] In still another aspect of the present invention, a co-planar gear set that provides a second gear ratio is adjacent one of the plurality of supporting walls. [0009] In yet another aspect of the present invention, a co-planar gear set that provides a third gear ratio is adjacent one of the plurality of supporting walls. 3 [0010] In yet another aspect of the present invention, a co-planar gear set that provides a fourth gear ratio is adjacent one of the plurality of supporting walls. [0011] In yet another aspect of the present .invention, a co-planar gear set that provides a fifth gear ratio is adjacent one of the plurality of supporting walls. [0012] In yet another aspect of the present invention, a co-planar gear set that provides a sixth gear ratio is adjacent one of the plurality of supporting walls. [0013] In yet another aspect of the present invention, a co-planar gear set that provides a seventh gear ratio is adjacent one of the plurality of supporting walls. [0014] The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIGURE 1 is a schematic representation of a first embodiment of a transmission in accordance with the invention; [0016] FIGURE 2 is a schematic representation of a second embodiment of a transmission in accordance with the invention; and [0017] FIGURE 3 is a schematic representation of a third embodiment of a transmission in accordance with the invention. DESCRIPTION [0018] Referring to the drawings, wherein like reference numbers refer to like components, in Fig. 1 a multi-speed transmission 10 is depicted. The transmission 10 includes an input member 12 and output member 14. In the present embodiment, the input member 12 and the output member 14 are shafts, and will be referred to as such. Those skilled in the art will appreciate that the input and output 4 members 12, 14 may be components other than shafts. The input shaft 12 is continuously connected with a torque converter 16 or other starting device. An engine (not shown) is connected to and provides a driving torque to the torque converter 16. The output shaft 14 is continuously connected with a final drive unit 18. The transmission 10 includes a countershaft gearing arrangement 20 that includes intermediate shafts, countershafts, co-planar intermeshing gear sets and selectively engagable synchronizers as will be described herein. For instance, the countershaft gearing arrangement 20 includes a first intermediate shaft 22 and a second intermediate shaft 24, which is a sleeve shaft concentric with the first intermediate shaft 22. The countershaft gearing arrangement 20 further includes a first countershaft 26 and a second countershaft 28. The countershafts 26 and 28 are both spaced from and parallel with the input shaft 12, the output shaft 14 and the intermediate shafts 22, 24. [0019] The first and second intermediate shafts 22, 24, first and second countershafts 26, 28 and output shaft 14 are supported by a first, second and third support structure or wall 23. 25, 27 formed in the housing of transmission 10. As conventionally known, the walls 23, 25, 27 are fitted with bearings 29 for rotatably supporting the first and second intermediate shafts 22. 24. first and second countershafts 26, 28 and output shaft 14. Wall 23 is disposed closest to the torque converter 16 and the final drive unit 18. Wall 25 is disposed adjacent wall 23 and wall 27 is disposed adjacent wall 25. [0020] A dual clutch 30 is packaged between input shaft 12 and first and second intermediate shafts 22, 24. The dual clutch 30 includes a clutch housing 32 connected for common rotation with input shaft 12. Further, clutch 30 has a first and a second clutch elements or hubs 34 and 36. Clutch elements 34 and 36 together with housing 32 are configured to form a friction clutch, as well known in the art as a dual clutch. More specifically, clutch elements 34, 36 and clutch housing 32 have friction plates mounted thereon that interact to form a friction clutch. Further, clutch clement 34 is connected for common rotation with.first intermediate shall 22 and clutch element 36 is connected for common rotation with second intermediate shaft 5 24. Thus, selective engagement of clutch clement 34 with clutch housing 32, connects the input shaft 12 for common rotation with first intermediate shaft 22 and selective engagement of clutch element 36 with clutch housing 32. connects the input shaft 12 for common rotation with second intermediate shaft 24. [0021] The countershaft gearing arrangement 20 also includes co-planar, intcrmeshing gear sets 40, 50, 60, 70, 80, 90 and 100. Gear set 40 includes transfer gears 42 and 44. Gear 42 is connected for common rotation with output shaft 14 and intermeshes with gear 44. Gear 44 is connected for common rotation with first countershaft 26. As shown in fig. 1, gear set 40 is disposed adjacent wall 23 and transfers torque from first countershaft 26 to output shaft 14. (00221 Co-planar gear set 50 includes transfer gears 52 and 54. Transfer gear 52 is connected for common rotation with 'Second countershaft 28 and intermeshes with gear 54. Transfer gear 54 is connected for common rotation with output shaft 14. As shown in fig. 1, gear set 50 is disposed adjacent gear set 40 and transfers torque from second countershaft 28 to output shaft 14. [0023] Gear set 60 includes co-planar intermeshing gears 62, 64, 66 and 68. Gear 62 is connected for common rotation with second intermediate shaft 24 and intermeshes with idler gear 66 and gear 68. Gear 64 is selectively connectable with first countershaft 26 and intermeshes with idler gear 66. Idler gear 66 is rotatable about idler axis /. Gear 68 is selectively connectable with second countershaft 28. As shown in Fig. 1, gear set 60 is disposed adjacent gear set 50 and provides second and reverse gear ratios. [0024] Gear set 70 includes co-planar, intermeshing gears 72, 74 and 76. Gear 72 is connected for common rotation with second intermediate shaft 24. Gear 72 intermeshes with gears 74 and 76. Gear 74 is selectively connectable for common rotation with first countershaft 26. Gear 76 is selectively connectable for common rotation with second countershaft 28. As shown in Fig. 1, gear set 70 is disposed adjacent gear set 60 and wall 25 and provides fourth and sixth gear ratios. [0025] Gear set 80 includes co-planar, intermeshing gears 82, 84 and 86. Gear 82 is connected for common rotation with first'intermediate shaft 22. Gear 82 6 intcrmcshes with gears 84 and 86. Gear 84 is selectively connectablc with first countershaft 26. Gear 86 is selectively connectable with second countershaft 28. As shown in Fig. 1, gear set 80 is disposed adjacent wall 25 and provides fifth and seventh gear ratios. [0026] Gear set 90 includes co-planar, intermeshing gears 92 and 94. Gear 92 is connected for common rotation with first intermediate shaft 22. Gear 92 intcrmcshes with gear 94. Gear 94 is selectively connectable for common rotation with second countershaft 28. As shown in Fig. 1, gear set 90 is disposed adjacent gear set 80 and provides a third gear ratio. [0027] Gear set 100 includes co-planar, intermeshing gears 102 and 104. Gear 102 is connected for common rotation with first intermediate shaft 22. Gear 102 intermeshes with gear 104. Gear 104 is selectively connectable for common rotation with the first countershaft 26. As shown in Fig. 1, gear set 100 is disposed adjacent gear set 90 and wall 17 and provides a first gear ratio. [0028] The transmission 10 further includes a plurality of selectively engagable synchronizers 110. 112, 114, 116, 118, 120, 122 and 124. Synchronizers 110/112. 114/116, 118/120 and 122/124 are a left and right side of synchronizer assemblies, sharing a common synchronizer hub and sleeve. Synchronizer 110 is selectively engagable to connect gear 64 with first countershaft 26 for common rotation therewith. Synchronizer 112 is selectively engagable to connect gear 74 with first countershaft 26 for common rotation therewith. Synchronizer 114 is selectively engagable to connect gear 68 with second countershaft 28 for common rotation therewith. Synchronizer 116 is selectively engagable to connect gear 76 with second countershaft 28 for common rotation therewith. Synchronizer 118 is selectively engagable to connect gear 84 with first countershaft 26 for common rotation therewith. Synchronizer 120 is selectively engagable to connect gear 104 with first countershaft 26 for common rotation therewith. Synchronizer 122 is selectively engagable to connect gear 86 with second countershaft 28 for common rotation therewith. Synchronizer 124 is selectively engagable to connect gear 94 with second countershaft 28 for common rotation therewith. 7 [0029] The transmission 10 is capable of transmitting torque from the input shalt 12 to the output shaft 14 in at least seven forward torque ratios and one reverse torque ratio. Each of the forward torque ratios and the reverse torque ratio is attained by engagement of dual clutch 30 and one of the clutch elements 34, 36 and one or more of the synchronizers 110, 112, 114, 116, 118, 120, 122 and 124. Those skilled in the art will readily understand that a different speed ratio is associated with each torque ratio. [0030] To establish the reverse torque ratio clutch element 36 of the dual clutch 30 and synchronizer 110 are engaged. By the engagement of clutch element 36 of the dual clutch 30, torque is transferred from the input shaft 12 through clutch housing 32 to the second intermediate shaft 24. Further, torque is transferred from the second intermediate shaft 24 through gear 62 to idler gear 66. Idler gear 66 transfers the torque to gear 64. Upon engagement of synchronizer 110, gear 64 transfers torque to first countershaft 26. first countershaft 26 transfers the torque to transfer gear 44. transfer gear 44 transfers torque to transfer gear 42, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [0031] A first forward torque ratio (1st gear) is achieved by engaging clutch clement 34 of the dual clutch 30 and synchronizer 120. By the engagement of clutch element 34 of the dual clutch 30. torque is transferred from input shaft 12 through clutch housing 32 to the first intermediate shaft 22. Further, torque is transferred from the first intermediate shaft 22 to gear 102. Gear 102 transfers the torque to gear 104. Upon engagement of synchronizer 120, gear 104 transfers torque to first countershaft 26. First countershaft 26 transfers the torque to transfer gear 44. Transfer gear 44 transfers torque to transfer gear 42, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [0032] A subsequent forward torque ratio (2nd gear) is established by engagement of clutch element 36 of the dual clutch 30 and synchronizer 114. By the engagement of clutch element 36 of the dual clutch 30, torque is transferred from 8 input shaft 12 through clutch housing 32 to the second intermediate shaft 24. further, torque is transferred from the second intermediate shaft 24 to gear 62. Gear 62 transfers the torque to gear 68. Upon engagement of synchronizer 114, gear 68 transfers torque to second countershaft 28. Second countershaft 28 transfers the torque to transfer gear 52. Transfer gear 52 transfers torque to transfer gear 54. which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [0033] The subsequent torque ratio (3rd gear.) is established by engagement of clutch element 34 of the dual clutch 30 and synchronizer 124. By the engagement of clutch clement 34 of the dual clutch 30, torque is transferred from input shaft 12 through clutch housing 32 to the first intermediate shaft 22. Further, torque is transferred from the first intermediate shaft 22 to gear 92. Gear 92 transfers the torque to gear 94. Upon engagement of synchronizer-124, torque is transferred from gear 94 to second countershaft 28. Second countershaft 28 transfers the torque to transfer gear 52. Transfer gear 52 transfers torque to. transfer gear 54, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [0034] The next subsequent forward torque ratio (4th gear) is established by engagement of clutch element 36 of the dual clutch 30 and synchronizer 112. By the engagement of clutch element 36 of the dual clutch 30, torque is transferred from input shaft 12 through clutch housing 32 to the second intermediate shaft 24. further, torque is transferred from the second intermediate shaft 24 to gear 72. Gear 72 transfers the torque to gear 74. Upon engagement of synchronizer 112. torque is transferred from gear 74 to first countershaft 26. First countershaft 26 transfers the torque to transfer gear 44. Transfer gear 44 transfers torque to transfer gear 42, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [00351 The subsequent torque ratio (5n gear) is established by engagement of clutch element 34 of the dual clutch 30 and synchronizer 118. By the engagement of clutch element 34 of the dual clutch 30, torque is transferred from input shaft 12 9 through clutch housing 32 to the first intermediate shaft 22. Further, torque is transferred from the first intermediate shaft 22 to gear 82. Gear 82 transfers the torque to gear 84. Upon engagement of synchronizer 118, gear 84 transfers torque to first countershaft 26. First countershaft 26 transfers the torque to transfer gear 44. Transfer gear 44 transfers torque to transfer gear 42, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 1 8. [0036] A subsequent forward torque ratio' (6lh gear) is established by engagement of clutch clement 36 of the dual clutch 30 and synchronizer 1 16. By the engagement of clutch element 36 of the dual clutch,30, torque is transferred from input shaft 12 through clutch housing 32 to the second intermediate shaft 24. Further, torque is transferred from the second intermediate shaft 24 to gear 72. Gear 72 transfers the torque to gear 76. Upon engagement of synchronizer 116, torque is transferred from gear 76 to the second countershaft 28. Second countershaft 28 transfers the torque to transfer gear 52. Transfer gear 52 transfers torque to transfer gear 54, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [0037] The subsequent torque ratio (7th gear) is established by engagement of clutch clement 34 of the dual clutch 30 and synchronizer 122. By the engagement of clutch element 34 of the dual clutch 30, torque is transferred from input shaft 12 through clutch housing 32 to the first intermediate shaft 22. Further, torque is transferred from the first intermediate shaft 22 to gear 82. Gear 82 transfers the torque to gear 86. Upon engagement of synchronizer 122, torque is transferred from gear 86 to second countershaft 28. Second countershaft 28 transfers the torque to transfer gear 52. Transfer gear 52 transfers torque to transfer gear 54, which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit 18. [0038] The present invention contemplates that a variety of torque ratios (i.e.. the ratio of torque of the output member 14 to the input member 12) are achievable through the selection of tooth counts of the gears of the transmission 10. 10 Moreover, the present invention advantageously provides the transfer gears 42, 44, 52. 54 in two separate planes. This arrangement provides the opportunity to achieve the desired gear ratios. Further, flexibility is provided in the selection of gear ratios with respect to 1st gear and 3rd gear, as the gears (102, 104, 92 and 94) that provide these ratios are disposed in two separate planes, and do not share the same pinion gears (i.e. pinion gear 92 does not mesh with gears 102 and/or 104). An overall transmission length reduction is achieved using idler gear 66, which is disposed in a single plane. Second 1 Embodiment [0039] Referring to figure 2 a multi-speed transmission 200 is depicted. The transmission 200 includes an input member 12 and"output member 14. In the present embodiment, the input member 12 and the output member 14 are shafts, and will be referred to as such. Those skilled in the art will appreciate that the input and output members 12, 14 may be components other than shafts. The input shaft 12 is continuously connected with a torque converter 16 or other starting device. An engine (not shown) is connected to and provides a driving torque to the torque converter 16. The output shaft 14 is continuously connected with a final drive unit 18. The transmission 200 includes a countershaft gearing arrangement 21 that includes intermediate shafts, countershafts, co-plariar intermeshing gear sets and selectively engagable synchronizers as will be described herein. For instance, the countershaft gearing arrangement 21 includes a firs't intermediate shaft 22 and a second intermediate shaft 24, which is a sleeve shaft concentric with the first intermediate shaft 22. The countershaft gearing arrangement 21 further includes a first countershaft 26 and a second countershaft 28. The countershafts 26 and 28 are both spaced from and parallel with the input shaft 12, the output shaft 14 and the intermediate shafts 22, 24. [0040] The first and second intermediate shafts 22, 24, first and second countershafts 26, 28 and output shaft 14 are supported by a first, second and third support structure or wall 23. 25. 27 formed in the housing of transmission 200. As conventionally known, the walls 23, 25, 27 are fitted with bearings 29 for rotatably 11 supporting the first and second intermediate shafts 22, 24, first and second countershafts 26, 28 and output shaft 14. Wall 23 is disposed closest to the torque converter 16 and the final drive unit 18. Wall 25 is disposed adjacent wall 23 and wall 27 is disposed adjacent wall 25. [00411 A dual clutch 30 is connected between input shaft 12 and first and second intermediate shafts 22, 24. The dual clutch 30 includes a clutch housing 32 connected for common rotation with input shaft 12. Further, clutch 30 has a first and a second clutch elements or hubs 34 and 36. Clutch elements 34 and 36 together with housing 32 arc configured to form a friction clutch, as well known in the art as a dual clutch. More specifically, clutch elements 34, 36 and clutch housing 32 have friction plates mounted thereon that interact to form a friction clutch. Further, clutch element 34 is connected for common rotation with first intermediate shaft 22 and clutch element 36 is connected for common rotation with second intermediate shaft 24. Thus, selective engagement of clutch element 34 with clutch housing 32. connects the input shaft 12 for common rotation with first intermediate shaft 22 and selective engagement of clutch element 36 with clutch housing 32, connects the input shaft 12 for common rotation with second intermediate shaft 24. \|0042"\| The countershaft gearing arrangement 21 also includes co-planar, intermeshing gear sets 40, 50. 60, 70, 80. 90 and 100. Gear set 40 includes transfer gears 42 and 44. Gear 42 is connected for common rotation with output shaft 14 and intermeshes with gear 44. Gear 44 is connected for common rotation with first countershaft 26. As shown in Fig. 2, gear set 40 is disposed adjacent wall 23 and transfers torque from first countershaft 26 to output shaft 14. [0043J Co-planar gear set 50 includes transfer gears 52 and 54. Transfer gear 52 is connected for common rotation with second countershaft 28 and intermeshes with gear 54. Transfer gear 54 is connected for common rotation with output shaft 14. As shown in Fig. 2, gear set 50 is disposed adjacent gear set 40 and transfers torque from second countershaft 28 to output shaft 14. [0044] Gear set 60 includes co-planar intermeshing gears 62, 64, 66 and 68. Gear 62 is connected for common rotation with second intermediate shaft 24 and 12 intcrmcshcs with idler gear 66 and gear 68. Gear 64 is selectively connectable with first countershaft 26 and intermeshes with idler gear 66. Idler gear 66 is rotatable about idler axis 1. Gear 68 is selectively connectable with second countershaft 28. As shown in Fig. 2, gear set 60 is disposed adjacent gear set 50 and provides sixth and reverse gear ratios. [0045] Gear set 70 includes co-planar, intermeshing gears 72, 74 and 76. Gear 72 is connected for common rotation with second intermediate shaft 24. Gear 72 intermeshes with gears 74 and 76. Gear 74 is selectively connectable for common rotation with first countershaft 26. Gear 76 is selectively connectable for common rotation with second countershaft 28. As shown in Fig. 2, gear set 70 is disposed adjacent gear set 60 and wall 25 and provides second and fourth gear ratios. [0046] Gear set 80 includes co-planar, intermeshing gears 82, 84 and 86. Gear 82 is connected for common rotation with first intermediate shaft 22. Gear 82 intermeshes with gears 84 and 86. Gear 84 is selectively connectable with first countershaft 26. Gear 86 is selectively connectable with second countershaft 28. As shown in Fig. 2, gear set 80 is disposed adjacent wall 27 and provides first and third gear ratios. [0047] Gear set 90 includes co-planar, intermeshing gears 92 and 94. Gear 92 is connected for common rotation with first intermediate shaft 22. Gear 92 intermeshes with gear 94. Gear 94 is selectively connectable for common rotation with second countershaft 28. As shown in Fig. 2, gear set 90 is disposed adjacent wall 25 and provides a seventh gear ratio. [0048] Gear set 100 includes co-planar, intermeshing gears 102 and 104. Gear 102 is connected for common rotation with first intermediate shaft 22. Gear 102 intermeshes with gear 104. Gear 104 is selectively connectable for common rotation with the first countershaft 26. As shown in Fig. 2, gear set 100 is disposed between gear set 80 and gear set 90 and provides a fifth gear ratio. [0049] The transmission 200 further includes a plurality of selectively engagable synchronizers 110, 112, 114, 116, 118, 120, 122 and'124. Synchronizers 13 110/112. 114/116, 118/120 and 122/124 arc a left and right side of synchronizer assemblies, sharing a common synchronizer hub and sleeve. Synchronizer 110 is selectively engagable to connect gear 64 with first countershaft 26 for common rotation therewith. Synchronizer 112 is selectively engagable to connect gear 74 with first countershaft 26 for common rotation therewith. Synchronizer 114 is selectively engagable to connect gear 68 with second countershaft 28 for common rotation therewith. Synchronizer 116 is selectively engagable to connect gear 76 with second countershaft 28 for common rotation therewith. Synchronizer 118 is selectively engagable to connect gear 104 with first countershaft 26 for common rotation therewith. Synchronizer 120 is selectively engagable to connect gear 84 with first countershaft 26 for common rotation therewith. Synchronizer 122 is selectively engagable to connect gear 94 with second countershaft 28 for common rotation therewith. Synchronizer 124 is selectively engagable to connect gear 86 with second countershaft 28 for common rotation therewith. Further, the desired gear ratio is achieved by arranging transfer gears in two separate planes, and by using to separate pinion gears (i.e. pinion gears 92 and 102) to achieve the 5th and 7th gear ratios. Moreover, an overall transmission length reduction is achieved by utilizing a reverse gear (i.e. gear 66) that is disposed in a single plane. [0050] 'The transmission 200 is capable of transmitting torque from the input shaft 12 to the output shaft 14 in at least seven forward torque ratios and one reverse torque ratio, as indicated in Fig. 2. Each of the forward torque ratios and the reverse torque ratio is attained by engagement of dual clutch 30 and one of the clutch elements 34, 36 and one or more of the synchronizers 110, 112, 114, 116, 118. 120. 122 and 124. Those skilled in the art will readily understand that a different speed ratio is associated with each torque ratio and how these torque or speed ratios are achieved, based on the description of transmission 10 above. Third Embodiment [0051] Referring to Tig. 3 a multi-speed transmission 300 is depicted. The transmission 300 includes an input member 12 and output member 14 a torque converter 16, a final drive unit 18, and a countershaft gearing arrangement 20 that 14 includes intermediate shafts, countershafts, co-planar intermeshing gear sets and selectively engagable synchronizers as shown in Fig 1. and described above. I Iowever. the speed and torque ratios provided by the co-planar intermeshing gear sets are provided on the various gear sets as described in detail below. [0052] Gear sets 40 and 50 are transfer gears sets and provide the same function as described above with respect to the embodiment illustrated in Fig. 1. [0053] Gear set 60 includes co-planar intermeshing gears 62, 64, 66 and 68. Gear 62 is connected for common rotation with second intermediate shaft 24 and intermeshes with idler gear 66 and gear 68. Gear 64 is selectively connectable with first countershaft 26 and intermeshes with idler gear 66. Idler gear 66 is rotatable about idler axis /. Gear 68 is selectively connectable with second countershaft 28. As shown in Fig. 3, gear set 60 is disposed adjacent gear set 50 and provides sixth and reverse gear ratios. [0054] Gear set 70 includes co-planar, intermeshing gears 72, 74 and 76. Gear 72 is connected for common rotation with second intermediate shaft 24. Gear 72 intermeshes with gears 74 and 76. Gear 74 is selectively connectable for common rotation with first countershaft 26. Gear 76 is selectively connectable for common rotation with second countershaft 28. As shown in Fig. 3, gear set 70 is disposed adjacent gear set 60 and wall 25 and provides second and fourth gear ratios. [0055] Gear set 80 includes co-planar, intermeshing gears 82, 84 and 86. Gear 82 is connected for common rotation with first intermediate shaft 22. Gear 82 intermeshes with gears 84 and 86. Gear 84 is selectively connectable with first countershaft 26. Gear 86 is selectively connectable with second countershaft 28. As shown in Fig. 3, gear set 80 is disposed adjacent wall 25 and provides fifth and third gear ratios. [0056] Gear set 90 includes co-planar, intermeshing gears 92 and 94. Gear 92 is connected for common rotation with first intermediate shaft 22. Gear 92 intermeshes with gear 94. Gear 94 is selectively connectable for common rotation 15 with second counlcrshaii 28. As shown in Fig. 3, gear set 90 is disposed between gear sets 80 and 100 provides a seventh gear ratio. [0057] Gear set 100 includes co-planar, intermeshing gears 102 and 104. Gear 102 is connected for common rotation with first intermediate shaft 22. Gear 102 intermeshes with gear 104. Gear 104 is selectively connectable for common rotation with the first countershaft 26. As shown in Fig. 3, gear set 100 is disposed adjacent gear set 90 and wall 27 and provides a first gear ratio. [0058] As in the transmission 10, transmission 300 is capable of transmitting torque from the input shaft 12 to the output shaft 14 in at least seven forward torque ratios and one reverse torque ratio, as indicated in Fig. 3. Yiach of the forward torque ratios and the reverse torque ratio is attained by engagement of dual clutch 30 and one of the clutch elements 34. 36 and one or more of the synchronizers 110. 112. 114, 116. 118, 120, 122 and 124. Those skilled in the art will readily understand that a different speed ratio is associated with each torque ratio and how these torque or speed ratios are achieved, based on the description of transmission 10 above. Advantageously, the desired gear ratio is achieved by arranging the transfer gears (i.e. gears 42, 44. 52 and 54) in two separate planes, and by using separate pinion gears to achieve the 1st and 7th gear ratios. Moreover, an overall transmission length reduction is achieved by utilizing a reverse gear that is disposed in a single plane. [0059] Accordingly, the present embodiments of the invention have many advantages and benefits over the prior art. For example, the transmission of the present invention provides the final drive unit 18 with a final drive unit output shaft 130. Moreover, the final drive unit output shaft 130 is transverse or perpendicular to input member 12 and is disposed between the torque converter 16 and clutch 30. [0060] While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims. 16 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 concentric with the first intermediate shaft; a clutch selectively engagable to couple the transmission input member with one of the first and second intermediate shafts; a first countershaft radially spaced from the second intermediate shaft; a second countershaft radially spaced from the second intermediate shaft; a first set of gears connected for common rotation with one of the first and second intermediate shafts 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 at least one of the first and second countershafts for selectively transferring the torque to the at least one of the first and second countershafts when the clutch is engaged; a second sel of gears connected for common rotation with the other of the first and second intermediate shafts and intermeshing with a second set of gears selectively connectable for common rotation with at least one of the first and second countershafts to form a second plurality of co-planar gear sets for selectively transferring the torque to the at least one of the first and second countershafts when the clutch is engaged; an output shaft disposed radially outward of the second intermediate shaft; a first transfer gear coupled to the first countershaft for transferring torque from the first countershaft to the output shaft; and 17 a second transfer gear coupled to the second countershaft for transferring torque from the second countershaft to the output shaft. 2. The powertrain of claim 1 wherein the first set of gears is connected for common rotation with the first intermediate shal't and intermeshes with the first selectable set of gears to form the 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 at least one of the first and second countershafts for selectively transferring the torque to the at least one of the first and second countershafts when the clutch is engaged. 3. The powertrain of claim 2 wherein the second set of gears is connected for common rotation with the second intermediate shaft and intermeshes with the second selectable set of gears to form the 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 at least one of the first and second countershafts for selectively transferring the torque to the at least one of the first and second countershafts when the clutch is engaged. 4. The powertrain of claim 1 wherein the clutch is a dual clutch having a first clutch hub connected to the first intermediate shaft and a second clutch hub connected to the second intermediate shaft. 5. The powertrain of claim 1 further comprising a housing having a plurality of supporting walls for supporting the first and second intermediate shafts, the first and second countershafts, the input member, and the output shaft. 6. The powertrain of claim 5 wherein the first plurality of gear sets includes a co-planar gear set that provides a second gear ratio. 18 7. The powertrain of claim 6 wherein the co-planar gear set that provides the second gear ratio is adjacent one of the plurality of supporting walls. 8. The powertrain of claim 5 wherein the first plurality of gear sets includes a co-planar gear set that provides a fourth gear ratio. 9. The powertrain of claim 8 wherein the co-planar gear set that provides the fourth gear ratio is adjacent one of the plurality of supporting walls. 10. The powertrain of claim 5 wherein the first plurality of gear sets includes a co-planar gear set that provides a sixth gear ratio. 11. The powertrain of claim 10 wherein the co-planar gear set that provides the sixth gear ratio is adjacent one of the plurality of supporting walls. 12. The powertrain of claim 5 wherein the second plurality of gear sets includes a co-planar gear set that provides a first gear ratio. 13. The powertrain of claim 12 wherein the co-planar gear set that provides the first gear ratio is adjacent one of the plurality of supporting walls. 14. The powertrain of claim 13 wherein the co-planar gear set that provides the first gear ratio further includes a pinion gear that meshes with only one driven gear. 15. The powertrain of claim 5 wherein the second plurality of gear sets includes a co-planar gear set that provides a fifth gear ratio. 16. The powertrain of claim 14 wherein the co-planar gear set that provides the fifth gear ratio is adjacent one of the plurality of supporting walls. 19 17. The powertrain of claim 16 wherein the co-planar gear set that provides the fifth gear ratio further includes a pinion gear that meshes with only one driven gear. 18. The powertrain of claim 5 wherein the second plurality oi' gear sets includes a co-planar gear set that provides a third gear ratio. 19. the powertrain of claim 18 wherein the co-planar gear set that provides the third gear ratio is adjacent one of the plurality of supporting walls. 20. The powertrain of claim 19 wherein the co-planar gear set that provides the third gear ratio further includes a pinion gear that mesh with only one driven gear. 21. The powertrain of claim 5 wherein the second plurality of gear sets includes a co-planar gear set that provides a seventh gear ratio. 22. The powertrain of claim 21 wherein the co-planar gear set that provides the seventh gear ratio is adjacent one of the plurality of supporting walls. 23. The powertrain of claim 22 wherein the co-planar gear set that provides the seventh gear ratio further includes a pinion gear that meshes with only one driven gear. 24. The powertrain of claim 1 further comprising a reverse gear intermeshing with one of the co-planar gear sets of the first plurality of gear sets, wherein the reverse gear is supported by an idler shaft. 25. The powertrain of claim 1 wherein the output shaft is perpendicular with respect to the first and second intermediate shafts. 20 26. The powertrain of claim 12 wherein the co-planar gear sets that provide the first and seventh gear ratios further includes two pinion gears disposed in two separate planes and independently meshes with two separate driven gears. 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 first and second countershaft. A transfer gear set transfers torque from the countershaft 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.

Full Text

1
MULTI-SPEED TRANSMISSION WITH
A COUNTERSHAFT GEARING ARRANGEMENT
TECHNICAL FIELD
[0001] The invention relates to a multi-speed transmission having a
countershaft gearing arrangement.
BACKGROUND
[0002] A typical multi-speed, dual clutch transmission uses a combination
of two friction clutches and several dog clutch/synchronizers to achieve "power-
on" or dynamic shifts by alternating between one friction clutch and the other,
with the synchronizers being "pre-selected" for the oncoming ratio prior to
actually making the dynamic shift. "Power-on" shifting means that torque flow
from the engine need not be interrupted prior to making the shift. This concept
typically uses countershaft gears with a different, dedicated gear pair or set to
achieve each forward speed ratio. Accordingly, the total number of gears required
in this typical design is two times the number of forward speeds, plus three for
reverse. This necessitates a large number of required gear pairs, especially in
transmissions that have a relatively large number of forward speed ratios.
SUMMARY
[0003] In an aspect of the present invention, a powertrain having a
transmission input member, a power source for generating a torque in the input
member, a first intermediate shaft, a second intermediate shaft concentric with the
first intermediate shaft, a clutch, a first countershaft, a second countershaft, first
set of gears, a second set of gears, an output shaft and first and second transfer
gears is provided.

2
[0004] The first countershaft is radially spaced from the second
intermediate shaft. The second countershaft is radially spaced from the second
intermediate shaft. The clutch is selectively cngagable to couple the transmission
input member with one of the first and second intermediate shafts. The first set of
gears are connected for common rotation with one of the first and second
intermediate shafts and intermesh with a first selectable set of gears to form a first
plurality of co-planar gear sets. Each of the gears of the first selectable set of gears
is connectable for common rotation with at least one of the first and second
countershafts for selectively transferring the torque to the countershafts when the
clutch is engaged.
[0005] The second set of gears is connected for common rotation with the
other of the first and second intermediate shafts and intermeshes with a second set
of gears. The second set of gears are selectively connectable for common rotation
with at least one of the countershafts to form a second plurality of co-planar gear
sets for selectively transferring the torque to the countershafts when the clutch is
engaged.
[0006] The output shaft is disposed radially outward of the second
intermediate shaft. The first transfer gear is coupled to the first countershaft for
transferring torque from the first countershaft to the output shaft. The second
transfer gear is coupled to the second countershaft for transferring torque from the
second countershaft to the output shaft.
[0007] In another aspect of the present invention, a co-planar gear set that
provides a first gear ratio is adjacent one of the plurality of supporting walls.
[0008] In still another aspect of the present invention, a co-planar gear set
that provides a second gear ratio is adjacent one of the plurality of supporting
walls.
[0009] In yet another aspect of the present invention, a co-planar gear set
that provides a third gear ratio is adjacent one of the plurality of supporting walls.

3
[0010] In yet another aspect of the present invention, a co-planar gear set
that provides a fourth gear ratio is adjacent one of the plurality of supporting
walls.
[0011] In yet another aspect of the present .invention, a co-planar gear set
that provides a fifth gear ratio is adjacent one of the plurality of supporting walls.
[0012] In yet another aspect of the present invention, a co-planar gear set
that provides a sixth gear ratio is adjacent one of the plurality of supporting walls.
[0013] In yet another aspect of the present invention, a co-planar gear set
that provides a seventh gear ratio is adjacent one of the plurality of supporting
walls.
[0014] The above features and advantages and other features and advantages
of the present invention are readily apparent from the following detailed description
of the best modes for carrying out the invention when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIGURE 1 is a schematic representation of a first embodiment of a
transmission in accordance with the invention;
[0016] FIGURE 2 is a schematic representation of a second embodiment of a
transmission in accordance with the invention; and
[0017] FIGURE 3 is a schematic representation of a third embodiment of a
transmission in accordance with the invention.
DESCRIPTION
[0018] Referring to the drawings, wherein like reference numbers refer to
like components, in Fig. 1 a multi-speed transmission 10 is depicted. The
transmission 10 includes an input member 12 and output member 14. In the present
embodiment, the input member 12 and the output member 14 are shafts, and will be
referred to as such. Those skilled in the art will appreciate that the input and output

4
members 12, 14 may be components other than shafts. The input shaft 12 is
continuously connected with a torque converter 16 or other starting device. An
engine (not shown) is connected to and provides a driving torque to the torque
converter 16. The output shaft 14 is continuously connected with a final drive unit
18. The transmission 10 includes a countershaft gearing arrangement 20 that
includes intermediate shafts, countershafts, co-planar intermeshing gear sets and
selectively engagable synchronizers as will be described herein. For instance, the
countershaft gearing arrangement 20 includes a first intermediate shaft 22 and a
second intermediate shaft 24, which is a sleeve shaft concentric with the first
intermediate shaft 22. The countershaft gearing arrangement 20 further includes a
first countershaft 26 and a second countershaft 28. The countershafts 26 and 28 are
both spaced from and parallel with the input shaft 12, the output shaft 14 and the
intermediate shafts 22, 24.
[0019] The first and second intermediate shafts 22, 24, first and second
countershafts 26, 28 and output shaft 14 are supported by a first, second and third
support structure or wall 23. 25, 27 formed in the housing of transmission 10. As
conventionally known, the walls 23, 25, 27 are fitted with bearings 29 for rotatably
supporting the first and second intermediate shafts 22. 24. first and second
countershafts 26, 28 and output shaft 14. Wall 23 is disposed closest to the torque
converter 16 and the final drive unit 18. Wall 25 is disposed adjacent wall 23 and
wall 27 is disposed adjacent wall 25.
[0020] A dual clutch 30 is packaged between input shaft 12 and first and
second intermediate shafts 22, 24. The dual clutch 30 includes a clutch housing 32
connected for common rotation with input shaft 12. Further, clutch 30 has a first
and a second clutch elements or hubs 34 and 36. Clutch elements 34 and 36 together
with housing 32 are configured to form a friction clutch, as well known in the art as
a dual clutch. More specifically, clutch elements 34, 36 and clutch housing 32 have
friction plates mounted thereon that interact to form a friction clutch. Further, clutch
clement 34 is connected for common rotation with.first intermediate shall 22 and
clutch element 36 is connected for common rotation with second intermediate shaft

5
24. Thus, selective engagement of clutch clement 34 with clutch housing 32,
connects the input shaft 12 for common rotation with first intermediate shaft 22 and
selective engagement of clutch element 36 with clutch housing 32. connects the
input shaft 12 for common rotation with second intermediate shaft 24.
[0021] The countershaft gearing arrangement 20 also includes co-planar,
intcrmeshing gear sets 40, 50, 60, 70, 80, 90 and 100. Gear set 40 includes transfer
gears 42 and 44. Gear 42 is connected for common rotation with output shaft 14 and
intermeshes with gear 44. Gear 44 is connected for common rotation with first
countershaft 26. As shown in fig. 1, gear set 40 is disposed adjacent wall 23 and
transfers torque from first countershaft 26 to output shaft 14.
(00221 Co-planar gear set 50 includes transfer gears 52 and 54. Transfer
gear 52 is connected for common rotation with 'Second countershaft 28 and
intermeshes with gear 54. Transfer gear 54 is connected for common rotation with
output shaft 14. As shown in fig. 1, gear set 50 is disposed adjacent gear set 40 and
transfers torque from second countershaft 28 to output shaft 14.
[0023] Gear set 60 includes co-planar intermeshing gears 62, 64, 66 and 68.
Gear 62 is connected for common rotation with second intermediate shaft 24 and
intermeshes with idler gear 66 and gear 68. Gear 64 is selectively connectable with
first countershaft 26 and intermeshes with idler gear 66. Idler gear 66 is rotatable
about idler axis /. Gear 68 is selectively connectable with second countershaft 28.
As shown in Fig. 1, gear set 60 is disposed adjacent gear set 50 and provides second
and reverse gear ratios.
[0024] Gear set 70 includes co-planar, intermeshing gears 72, 74 and 76.
Gear 72 is connected for common rotation with second intermediate shaft 24. Gear
72 intermeshes with gears 74 and 76. Gear 74 is selectively connectable for
common rotation with first countershaft 26. Gear 76 is selectively connectable for
common rotation with second countershaft 28. As shown in Fig. 1, gear set 70 is
disposed adjacent gear set 60 and wall 25 and provides fourth and sixth gear ratios.
[0025] Gear set 80 includes co-planar, intermeshing gears 82, 84 and 86.
Gear 82 is connected for common rotation with first'intermediate shaft 22. Gear 82

6
intcrmcshes with gears 84 and 86. Gear 84 is selectively connectablc with first
countershaft 26. Gear 86 is selectively connectable with second countershaft 28. As
shown in Fig. 1, gear set 80 is disposed adjacent wall 25 and provides fifth and
seventh gear ratios.
[0026] Gear set 90 includes co-planar, intermeshing gears 92 and 94. Gear
92 is connected for common rotation with first intermediate shaft 22. Gear 92
intcrmcshes with gear 94. Gear 94 is selectively connectable for common rotation
with second countershaft 28. As shown in Fig. 1, gear set 90 is disposed adjacent
gear set 80 and provides a third gear ratio.
[0027] Gear set 100 includes co-planar, intermeshing gears 102 and 104.
Gear 102 is connected for common rotation with first intermediate shaft 22. Gear
102 intermeshes with gear 104. Gear 104 is selectively connectable for common
rotation with the first countershaft 26. As shown in Fig. 1, gear set 100 is disposed
adjacent gear set 90 and wall 17 and provides a first gear ratio.
[0028] The transmission 10 further includes a plurality of selectively
engagable synchronizers 110. 112, 114, 116, 118, 120, 122 and 124. Synchronizers
110/112. 114/116, 118/120 and 122/124 are a left and right side of synchronizer
assemblies, sharing a common synchronizer hub and sleeve. Synchronizer 110 is
selectively engagable to connect gear 64 with first countershaft 26 for common
rotation therewith. Synchronizer 112 is selectively engagable to connect gear 74
with first countershaft 26 for common rotation therewith. Synchronizer 114 is
selectively engagable to connect gear 68 with second countershaft 28 for common
rotation therewith. Synchronizer 116 is selectively engagable to connect gear 76
with second countershaft 28 for common rotation therewith. Synchronizer 118 is
selectively engagable to connect gear 84 with first countershaft 26 for common
rotation therewith. Synchronizer 120 is selectively engagable to connect gear 104
with first countershaft 26 for common rotation therewith. Synchronizer 122 is
selectively engagable to connect gear 86 with second countershaft 28 for common
rotation therewith. Synchronizer 124 is selectively engagable to connect gear 94
with second countershaft 28 for common rotation therewith.

7
[0029] The transmission 10 is capable of transmitting torque from the input
shalt 12 to the output shaft 14 in at least seven forward torque ratios and one reverse
torque ratio. Each of the forward torque ratios and the reverse torque ratio is
attained by engagement of dual clutch 30 and one of the clutch elements 34, 36 and
one or more of the synchronizers 110, 112, 114, 116, 118, 120, 122 and 124. Those
skilled in the art will readily understand that a different speed ratio is associated with
each torque ratio.
[0030] To establish the reverse torque ratio clutch element 36 of the dual
clutch 30 and synchronizer 110 are engaged. By the engagement of clutch element
36 of the dual clutch 30, torque is transferred from the input shaft 12 through clutch
housing 32 to the second intermediate shaft 24. Further, torque is transferred from
the second intermediate shaft 24 through gear 62 to idler gear 66. Idler gear 66
transfers the torque to gear 64. Upon engagement of synchronizer 110, gear 64
transfers torque to first countershaft 26. first countershaft 26 transfers the torque to
transfer gear 44. transfer gear 44 transfers torque to transfer gear 42, which in turn
transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the
final drive unit 18.
[0031] A first forward torque ratio (1st gear) is achieved by engaging clutch
clement 34 of the dual clutch 30 and synchronizer 120. By the engagement of clutch
element 34 of the dual clutch 30. torque is transferred from input shaft 12 through
clutch housing 32 to the first intermediate shaft 22. Further, torque is transferred
from the first intermediate shaft 22 to gear 102. Gear 102 transfers the torque to
gear 104. Upon engagement of synchronizer 120, gear 104 transfers torque to first
countershaft 26. First countershaft 26 transfers the torque to transfer gear 44.
Transfer gear 44 transfers torque to transfer gear 42, which in turn transfers the
torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit
18.
[0032] A subsequent forward torque ratio (2nd gear) is established by
engagement of clutch element 36 of the dual clutch 30 and synchronizer 114. By the
engagement of clutch element 36 of the dual clutch 30, torque is transferred from

8
input shaft 12 through clutch housing 32 to the second intermediate shaft 24.
further, torque is transferred from the second intermediate shaft 24 to gear 62.
Gear 62 transfers the torque to gear 68. Upon engagement of synchronizer 114, gear
68 transfers torque to second countershaft 28. Second countershaft 28 transfers the
torque to transfer gear 52. Transfer gear 52 transfers torque to transfer gear 54.
which in turn transfers the torque to output shaft 14. Output shaft 14 transfers the
torque to the final drive unit 18.
[0033] The subsequent torque ratio (3rd gear.) is established by engagement
of clutch element 34 of the dual clutch 30 and synchronizer 124. By the engagement
of clutch clement 34 of the dual clutch 30, torque is transferred from input shaft 12
through clutch housing 32 to the first intermediate shaft 22. Further, torque is
transferred from the first intermediate shaft 22 to gear 92. Gear 92 transfers the
torque to gear 94. Upon engagement of synchronizer-124, torque is transferred from
gear 94 to second countershaft 28. Second countershaft 28 transfers the torque to
transfer gear 52. Transfer gear 52 transfers torque to. transfer gear 54, which in turn
transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the
final drive unit 18.
[0034] The next subsequent forward torque ratio (4th gear) is established by
engagement of clutch element 36 of the dual clutch 30 and synchronizer 112. By the
engagement of clutch element 36 of the dual clutch 30, torque is transferred from
input shaft 12 through clutch housing 32 to the second intermediate shaft 24.
further, torque is transferred from the second intermediate shaft 24 to gear 72.
Gear 72 transfers the torque to gear 74. Upon engagement of synchronizer 112.
torque is transferred from gear 74 to first countershaft 26. First countershaft 26
transfers the torque to transfer gear 44. Transfer gear 44 transfers torque to transfer
gear 42, which in turn transfers the torque to output shaft 14. Output shaft 14
transfers the torque to the final drive unit 18.
[00351 The subsequent torque ratio (5n gear) is established by engagement
of clutch element 34 of the dual clutch 30 and synchronizer 118. By the engagement
of clutch element 34 of the dual clutch 30, torque is transferred from input shaft 12

9
through clutch housing 32 to the first intermediate shaft 22. Further, torque is
transferred from the first intermediate shaft 22 to gear 82. Gear 82 transfers the
torque to gear 84. Upon engagement of synchronizer 118, gear 84 transfers torque
to first countershaft 26. First countershaft 26 transfers the torque to transfer gear 44.
Transfer gear 44 transfers torque to transfer gear 42, which in turn transfers the
torque to output shaft 14. Output shaft 14 transfers the torque to the final drive unit
1 8.
[0036] A subsequent forward torque ratio' (6lh gear) is established by
engagement of clutch clement 36 of the dual clutch 30 and synchronizer 1 16. By the
engagement of clutch element 36 of the dual clutch,30, torque is transferred from
input shaft 12 through clutch housing 32 to the second intermediate shaft 24.
Further, torque is transferred from the second intermediate shaft 24 to gear 72.
Gear 72 transfers the torque to gear 76. Upon engagement of synchronizer 116,
torque is transferred from gear 76 to the second countershaft 28. Second
countershaft 28 transfers the torque to transfer gear 52. Transfer gear 52 transfers
torque to transfer gear 54, which in turn transfers the torque to output shaft 14.
Output shaft 14 transfers the torque to the final drive unit 18.
[0037] The subsequent torque ratio (7th gear) is established by engagement
of clutch clement 34 of the dual clutch 30 and synchronizer 122. By the engagement
of clutch element 34 of the dual clutch 30, torque is transferred from input shaft 12
through clutch housing 32 to the first intermediate shaft 22. Further, torque is
transferred from the first intermediate shaft 22 to gear 82. Gear 82 transfers the
torque to gear 86. Upon engagement of synchronizer 122, torque is transferred from
gear 86 to second countershaft 28. Second countershaft 28 transfers the torque to
transfer gear 52. Transfer gear 52 transfers torque to transfer gear 54, which in turn
transfers the torque to output shaft 14. Output shaft 14 transfers the torque to the
final drive unit 18.
[0038] The present invention contemplates that a variety of torque ratios
(i.e.. the ratio of torque of the output member 14 to the input member 12) are
achievable through the selection of tooth counts of the gears of the transmission 10.

10
Moreover, the present invention advantageously provides the transfer gears 42, 44,
52. 54 in two separate planes. This arrangement provides the opportunity to achieve
the desired gear ratios. Further, flexibility is provided in the selection of gear ratios
with respect to 1st gear and 3rd gear, as the gears (102, 104, 92 and 94) that provide
these ratios are disposed in two separate planes, and do not share the same pinion
gears (i.e. pinion gear 92 does not mesh with gears 102 and/or 104). An overall
transmission length reduction is achieved using idler gear 66, which is disposed in a
single plane.
Second 1 Embodiment
[0039] Referring to figure 2 a multi-speed transmission 200 is depicted.
The transmission 200 includes an input member 12 and"output member 14. In the
present embodiment, the input member 12 and the output member 14 are shafts, and
will be referred to as such. Those skilled in the art will appreciate that the input and
output members 12, 14 may be components other than shafts. The input shaft 12 is
continuously connected with a torque converter 16 or other starting device. An
engine (not shown) is connected to and provides a driving torque to the torque
converter 16. The output shaft 14 is continuously connected with a final drive unit
18. The transmission 200 includes a countershaft gearing arrangement 21 that
includes intermediate shafts, countershafts, co-plariar intermeshing gear sets and
selectively engagable synchronizers as will be described herein. For instance, the
countershaft gearing arrangement 21 includes a firs't intermediate shaft 22 and a
second intermediate shaft 24, which is a sleeve shaft concentric with the first
intermediate shaft 22. The countershaft gearing arrangement 21 further includes a
first countershaft 26 and a second countershaft 28. The countershafts 26 and 28 are
both spaced from and parallel with the input shaft 12, the output shaft 14 and the
intermediate shafts 22, 24.
[0040] The first and second intermediate shafts 22, 24, first and second
countershafts 26, 28 and output shaft 14 are supported by a first, second and third
support structure or wall 23. 25. 27 formed in the housing of transmission 200. As
conventionally known, the walls 23, 25, 27 are fitted with bearings 29 for rotatably

11
supporting the first and second intermediate shafts 22, 24, first and second
countershafts 26, 28 and output shaft 14. Wall 23 is disposed closest to the torque
converter 16 and the final drive unit 18. Wall 25 is disposed adjacent wall 23 and
wall 27 is disposed adjacent wall 25.
[00411 A dual clutch 30 is connected between input shaft 12 and first and
second intermediate shafts 22, 24. The dual clutch 30 includes a clutch housing 32
connected for common rotation with input shaft 12. Further, clutch 30 has a first
and a second clutch elements or hubs 34 and 36. Clutch elements 34 and 36 together
with housing 32 arc configured to form a friction clutch, as well known in the art as
a dual clutch. More specifically, clutch elements 34, 36 and clutch housing 32 have
friction plates mounted thereon that interact to form a friction clutch. Further, clutch
element 34 is connected for common rotation with first intermediate shaft 22 and
clutch element 36 is connected for common rotation with second intermediate shaft
24. Thus, selective engagement of clutch element 34 with clutch housing 32.
connects the input shaft 12 for common rotation with first intermediate shaft 22 and
selective engagement of clutch element 36 with clutch housing 32, connects the
input shaft 12 for common rotation with second intermediate shaft 24.
|0042"| The countershaft gearing arrangement 21 also includes co-planar,
intermeshing gear sets 40, 50. 60, 70, 80. 90 and 100. Gear set 40 includes transfer
gears 42 and 44. Gear 42 is connected for common rotation with output shaft 14 and
intermeshes with gear 44. Gear 44 is connected for common rotation with first
countershaft 26. As shown in Fig. 2, gear set 40 is disposed adjacent wall 23 and
transfers torque from first countershaft 26 to output shaft 14.
[0043J Co-planar gear set 50 includes transfer gears 52 and 54. Transfer
gear 52 is connected for common rotation with second countershaft 28 and
intermeshes with gear 54. Transfer gear 54 is connected for common rotation with
output shaft 14. As shown in Fig. 2, gear set 50 is disposed adjacent gear set 40 and
transfers torque from second countershaft 28 to output shaft 14.
[0044] Gear set 60 includes co-planar intermeshing gears 62, 64, 66 and 68.
Gear 62 is connected for common rotation with second intermediate shaft 24 and

12
intcrmcshcs with idler gear 66 and gear 68. Gear 64 is selectively connectable with
first countershaft 26 and intermeshes with idler gear 66. Idler gear 66 is rotatable
about idler axis 1. Gear 68 is selectively connectable with second countershaft 28.
As shown in Fig. 2, gear set 60 is disposed adjacent gear set 50 and provides sixth
and reverse gear ratios.
[0045] Gear set 70 includes co-planar, intermeshing gears 72, 74 and 76.
Gear 72 is connected for common rotation with second intermediate shaft 24. Gear
72 intermeshes with gears 74 and 76. Gear 74 is selectively connectable for
common rotation with first countershaft 26. Gear 76 is selectively connectable for
common rotation with second countershaft 28. As shown in Fig. 2, gear set 70 is
disposed adjacent gear set 60 and wall 25 and provides second and fourth gear
ratios.
[0046] Gear set 80 includes co-planar, intermeshing gears 82, 84 and 86.
Gear 82 is connected for common rotation with first intermediate shaft 22. Gear 82
intermeshes with gears 84 and 86. Gear 84 is selectively connectable with first
countershaft 26. Gear 86 is selectively connectable with second countershaft 28. As
shown in Fig. 2, gear set 80 is disposed adjacent wall 27 and provides first and third
gear ratios.
[0047] Gear set 90 includes co-planar, intermeshing gears 92 and 94. Gear
92 is connected for common rotation with first intermediate shaft 22. Gear 92
intermeshes with gear 94. Gear 94 is selectively connectable for common rotation
with second countershaft 28. As shown in Fig. 2, gear set 90 is disposed adjacent
wall 25 and provides a seventh gear ratio.
[0048] Gear set 100 includes co-planar, intermeshing gears 102 and 104.
Gear 102 is connected for common rotation with first intermediate shaft 22. Gear
102 intermeshes with gear 104. Gear 104 is selectively connectable for common
rotation with the first countershaft 26. As shown in Fig. 2, gear set 100 is disposed
between gear set 80 and gear set 90 and provides a fifth gear ratio.
[0049] The transmission 200 further includes a plurality of selectively
engagable synchronizers 110, 112, 114, 116, 118, 120, 122 and'124. Synchronizers

13
110/112. 114/116, 118/120 and 122/124 arc a left and right side of synchronizer
assemblies, sharing a common synchronizer hub and sleeve. Synchronizer 110 is
selectively engagable to connect gear 64 with first countershaft 26 for common
rotation therewith. Synchronizer 112 is selectively engagable to connect gear 74
with first countershaft 26 for common rotation therewith. Synchronizer 114 is
selectively engagable to connect gear 68 with second countershaft 28 for common
rotation therewith. Synchronizer 116 is selectively engagable to connect gear 76
with second countershaft 28 for common rotation therewith. Synchronizer 118 is
selectively engagable to connect gear 104 with first countershaft 26 for common
rotation therewith. Synchronizer 120 is selectively engagable to connect gear 84
with first countershaft 26 for common rotation therewith. Synchronizer 122 is
selectively engagable to connect gear 94 with second countershaft 28 for common
rotation therewith. Synchronizer 124 is selectively engagable to connect gear 86
with second countershaft 28 for common rotation therewith. Further, the desired
gear ratio is achieved by arranging transfer gears in two separate planes, and by
using to separate pinion gears (i.e. pinion gears 92 and 102) to achieve the 5th and 7th
gear ratios. Moreover, an overall transmission length reduction is achieved by
utilizing a reverse gear (i.e. gear 66) that is disposed in a single plane.
[0050] 'The transmission 200 is capable of transmitting torque from the
input shaft 12 to the output shaft 14 in at least seven forward torque ratios and one
reverse torque ratio, as indicated in Fig. 2. Each of the forward torque ratios and the
reverse torque ratio is attained by engagement of dual clutch 30 and one of the
clutch elements 34, 36 and one or more of the synchronizers 110, 112, 114, 116,
118. 120. 122 and 124. Those skilled in the art will readily understand that a
different speed ratio is associated with each torque ratio and how these torque or
speed ratios are achieved, based on the description of transmission 10 above.
Third Embodiment
[0051] Referring to Tig. 3 a multi-speed transmission 300 is depicted. The
transmission 300 includes an input member 12 and output member 14 a torque
converter 16, a final drive unit 18, and a countershaft gearing arrangement 20 that

14
includes intermediate shafts, countershafts, co-planar intermeshing gear sets and
selectively engagable synchronizers as shown in Fig 1. and described above.
I Iowever. the speed and torque ratios provided by the co-planar intermeshing gear
sets are provided on the various gear sets as described in detail below.
[0052] Gear sets 40 and 50 are transfer gears sets and provide the same
function as described above with respect to the embodiment illustrated in Fig. 1.
[0053] Gear set 60 includes co-planar intermeshing gears 62, 64, 66 and 68.
Gear 62 is connected for common rotation with second intermediate shaft 24 and
intermeshes with idler gear 66 and gear 68. Gear 64 is selectively connectable with
first countershaft 26 and intermeshes with idler gear 66. Idler gear 66 is rotatable
about idler axis /. Gear 68 is selectively connectable with second countershaft 28.
As shown in Fig. 3, gear set 60 is disposed adjacent gear set 50 and provides sixth
and reverse gear ratios.
[0054] Gear set 70 includes co-planar, intermeshing gears 72, 74 and 76.
Gear 72 is connected for common rotation with second intermediate shaft 24. Gear
72 intermeshes with gears 74 and 76. Gear 74 is selectively connectable for
common rotation with first countershaft 26. Gear 76 is selectively connectable for
common rotation with second countershaft 28. As shown in Fig. 3, gear set 70 is
disposed adjacent gear set 60 and wall 25 and provides second and fourth gear
ratios.
[0055] Gear set 80 includes co-planar, intermeshing gears 82, 84 and 86.
Gear 82 is connected for common rotation with first intermediate shaft 22. Gear 82
intermeshes with gears 84 and 86. Gear 84 is selectively connectable with first
countershaft 26. Gear 86 is selectively connectable with second countershaft 28. As
shown in Fig. 3, gear set 80 is disposed adjacent wall 25 and provides fifth and third
gear ratios.
[0056] Gear set 90 includes co-planar, intermeshing gears 92 and 94. Gear
92 is connected for common rotation with first intermediate shaft 22. Gear 92
intermeshes with gear 94. Gear 94 is selectively connectable for common rotation

15
with second counlcrshaii 28. As shown in Fig. 3, gear set 90 is disposed between
gear sets 80 and 100 provides a seventh gear ratio.
[0057] Gear set 100 includes co-planar, intermeshing gears 102 and 104.
Gear 102 is connected for common rotation with first intermediate shaft 22. Gear
102 intermeshes with gear 104. Gear 104 is selectively connectable for common
rotation with the first countershaft 26. As shown in Fig. 3, gear set 100 is disposed
adjacent gear set 90 and wall 27 and provides a first gear ratio.
[0058] As in the transmission 10, transmission 300 is capable of transmitting
torque from the input shaft 12 to the output shaft 14 in at least seven forward torque
ratios and one reverse torque ratio, as indicated in Fig. 3. Yiach of the forward torque
ratios and the reverse torque ratio is attained by engagement of dual clutch 30 and
one of the clutch elements 34. 36 and one or more of the synchronizers 110. 112.
114, 116. 118, 120, 122 and 124. Those skilled in the art will readily understand
that a different speed ratio is associated with each torque ratio and how these torque
or speed ratios are achieved, based on the description of transmission 10 above.
Advantageously, the desired gear ratio is achieved by arranging the transfer gears
(i.e. gears 42, 44. 52 and 54) in two separate planes, and by using separate pinion
gears to achieve the 1st and 7th gear ratios. Moreover, an overall transmission length
reduction is achieved by utilizing a reverse gear that is disposed in a single plane.
[0059] Accordingly, the present embodiments of the invention have many
advantages and benefits over the prior art. For example, the transmission of the
present invention provides the final drive unit 18 with a final drive unit output shaft
130. Moreover, the final drive unit output shaft 130 is transverse or perpendicular
to input member 12 and is disposed between the torque converter 16 and clutch 30.
[0060] While the best modes for carrying out the invention have been
described in detail, those familiar with the art to which this invention relates will
recognize various alternative designs and embodiments for practicing the invention
within the scope of the appended claims.

16
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 concentric with the first intermediate
shaft;
a clutch selectively engagable to couple the transmission input
member with one of the first and second intermediate shafts;
a first countershaft radially spaced from the second intermediate
shaft;
a second countershaft radially spaced from the second intermediate
shaft;
a first set of gears connected for common rotation with one of the
first and second intermediate shafts 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 at least one of
the first and second countershafts for selectively transferring the torque to the at
least one of the first and second countershafts when the clutch is engaged;
a second sel of gears connected for common rotation with the other of
the first and second intermediate shafts and intermeshing with a second set of gears
selectively connectable for common rotation with at least one of the first and second
countershafts to form a second plurality of co-planar gear sets for selectively
transferring the torque to the at least one of the first and second countershafts when
the clutch is engaged;
an output shaft disposed radially outward of the second intermediate
shaft;
a first transfer gear coupled to the first countershaft for transferring
torque from the first countershaft to the output shaft; and

17
a second transfer gear coupled to the second countershaft for
transferring torque from the second countershaft to the output shaft.
2. The powertrain of claim 1 wherein the first set of gears is
connected for common rotation with the first intermediate shal't and intermeshes
with the first selectable set of gears to form the 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 at least one of the first and second countershafts for
selectively transferring the torque to the at least one of the first and second
countershafts when the clutch is engaged.
3. The powertrain of claim 2 wherein the second set of gears is
connected for common rotation with the second intermediate shaft and intermeshes
with the second selectable set of gears to form the 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 at least one of the first and second countershafts for
selectively transferring the torque to the at least one of the first and second
countershafts when the clutch is engaged.
4. The powertrain of claim 1 wherein the clutch is a dual clutch
having a first clutch hub connected to the first intermediate shaft and a second clutch
hub connected to the second intermediate shaft.
5. The powertrain of claim 1 further comprising a housing
having a plurality of supporting walls for supporting the first and second
intermediate shafts, the first and second countershafts, the input member, and the
output shaft.
6. The powertrain of claim 5 wherein the first plurality of gear
sets includes a co-planar gear set that provides a second gear ratio.

18
7. The powertrain of claim 6 wherein the co-planar gear set that
provides the second gear ratio is adjacent one of the plurality of supporting walls.
8. The powertrain of claim 5 wherein the first plurality of gear
sets includes a co-planar gear set that provides a fourth gear ratio.
9. The powertrain of claim 8 wherein the co-planar gear set that
provides the fourth gear ratio is adjacent one of the plurality of supporting walls.
10. The powertrain of claim 5 wherein the first plurality of gear
sets includes a co-planar gear set that provides a sixth gear ratio.
11. The powertrain of claim 10 wherein the co-planar gear set that
provides the sixth gear ratio is adjacent one of the plurality of supporting walls.
12. The powertrain of claim 5 wherein the second plurality of
gear sets includes a co-planar gear set that provides a first gear ratio.
13. The powertrain of claim 12 wherein the co-planar gear set that
provides the first gear ratio is adjacent one of the plurality of supporting walls.
14. The powertrain of claim 13 wherein the co-planar gear set that
provides the first gear ratio further includes a pinion gear that meshes with only one
driven gear.
15. The powertrain of claim 5 wherein the second plurality of
gear sets includes a co-planar gear set that provides a fifth gear ratio.
16. The powertrain of claim 14 wherein the co-planar gear set that
provides the fifth gear ratio is adjacent one of the plurality of supporting walls.

19
17. The powertrain of claim 16 wherein the co-planar gear set that
provides the fifth gear ratio further includes a pinion gear that meshes with only one
driven gear.
18. The powertrain of claim 5 wherein the second plurality oi'
gear sets includes a co-planar gear set that provides a third gear ratio.
19. the powertrain of claim 18 wherein the co-planar gear set that
provides the third gear ratio is adjacent one of the plurality of supporting walls.
20. The powertrain of claim 19 wherein the co-planar gear set that
provides the third gear ratio further includes a pinion gear that mesh with only one
driven gear.
21. The powertrain of claim 5 wherein the second plurality of
gear sets includes a co-planar gear set that provides a seventh gear ratio.
22. The powertrain of claim 21 wherein the co-planar gear set that
provides the seventh gear ratio is adjacent one of the plurality of supporting walls.
23. The powertrain of claim 22 wherein the co-planar gear set that
provides the seventh gear ratio further includes a pinion gear that meshes with only
one driven gear.
24. The powertrain of claim 1 further comprising a reverse gear
intermeshing with one of the co-planar gear sets of the first plurality of gear sets,
wherein the reverse gear is supported by an idler shaft.
25. The powertrain of claim 1 wherein the output shaft is
perpendicular with respect to the first and second intermediate shafts.

20
26. The powertrain of claim 12 wherein the co-planar gear sets
that provide the first and seventh gear ratios further includes two pinion gears
disposed in two separate planes and independently meshes with two separate driven
gears.

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 first and second countershaft. A transfer gear set transfers torque from the
countershaft 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.

Documents:

00216-kol-2008-abstract.pdf

00216-kol-2008-claims.pdf

00216-kol-2008-correspondence others.pdf

00216-kol-2008-description complete.pdf

00216-kol-2008-drawings.pdf

00216-kol-2008-form 1.pdf

00216-kol-2008-form 2.pdf

00216-kol-2008-form 3.pdf

00216-kol-2008-form 5.pdf

00216-kol-2008-priority document.pdf

216-KOL-2008-(02-05-2014)-ABSTRACT.pdf

216-KOL-2008-(02-05-2014)-CLAIMS.pdf

216-KOL-2008-(02-05-2014)-CORRESPONDENCE-1.pdf

216-KOL-2008-(02-05-2014)-CORRESPONDENCE.pdf

216-KOL-2008-(02-05-2014)-DESCRIPTION (COMPLETE).pdf

216-KOL-2008-(02-05-2014)-DRAWINGS.pdf

216-KOL-2008-(02-05-2014)-FORM-1.pdf

216-KOL-2008-(02-05-2014)-FORM-2.pdf

216-KOL-2008-(02-05-2014)-OTHERS.pdf

216-KOL-2008-(02-05-2014)-PETITION UNDER RULE 137.pdf

216-KOL-2008-(25-10-2013)-ABSTRACT.pdf

216-KOL-2008-(25-10-2013)-ANNEXURE TO FORM 3.pdf

216-KOL-2008-(25-10-2013)-CLAIMS.pdf

216-KOL-2008-(25-10-2013)-CORRESPONDENCE.pdf

216-KOL-2008-(25-10-2013)-DESCRIPTION (COMPLETE).pdf

216-KOL-2008-(25-10-2013)-DRAWINGS.pdf

216-KOL-2008-(25-10-2013)-FORM-1.pdf

216-KOL-2008-(25-10-2013)-FORM-2.pdf

216-KOL-2008-(25-10-2013)-OTHERS.pdf

216-KOL-2008-(25-10-2013)-PA.pdf

216-KOL-2008-ASSIGNMENT 1.1.pdf

216-KOL-2008-ASSIGNMENT.pdf

216-KOL-2008-CORRESPONDENCE OTHERS 1.1.pdf

216-KOL-2008-CORRESPONDENCE OTHERS 1.2.pdf

216-KOL-2008-CORRESPONDENCE OTHERS 1.3.pdf

216-kol-2008-form 18.pdf

216-KOL-2008-OTHERS.pdf

abstract-00216-kol-2008.jpg

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Patent Number

265178

Indian Patent Application Number

216/KOL/2008

PG Journal Number

07/2015

Publication Date

13-Feb-2015

Grant Date

12-Feb-2015

Date of Filing

07-Feb-2008

Name of Patentee

GM GLOBAL TECHNOLOGY OPERATIONS, INC.

Applicant Address

300 GM RENAISSANCE CENTER DETROIT, MICHIGAN

Inventors:

#	Inventor's Name	Inventor's Address
1	TEJINDER SINGH	8002 LABANA COURT CANTON, MICHIGAN 48187
2	HENRYK SOWUL	491 HARWOOD COURT OXFORD, MICHIGAN 48371
3	JAMES D. HENDRICKSON	42040 HAYES BELLEVILLE, MICHIGAN 48111

PCT International Classification Number

F16H3/08; F16H3/087;F16H61/48; F16H61/38

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	11/676,862	2007-02-20	U.S.A.