CN102047003A

CN102047003A - Double-clutch transmission for vehicles

Info

Publication number: CN102047003A
Application number: CN2009801200924A
Authority: CN
Inventors: 迈克尔·B·莫琳; 阿克塞尔·盖伯格; 马塞厄斯·雷姆勒; 马库斯·罗肯巴克
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2008-03-31
Filing date: 2009-03-31
Publication date: 2011-05-04

Abstract

Double-clutch transmission (1) (DCT) comprises an inner input shaft (20) inside an outer input shaft (22). Two clutches (8, 10) of the DCT (1) are connected to the input shafts (20, 22) respectively. The DCT (1) has three layshafts (40, 50, 38) that are parallel to the input shafts (20, 22). One or more pinions (41, 51) are fixed onto the layshafts (40, 50) respectively. Seven forward gearwheel groups and one reverse gearwheel group of the DCT (1) are arranged on the shafts (20, 22, 40, 50, 38). Each one of the gearwheel groups comprises a fixed gearwheel on one of the input shafts (20, 22), meshing with an idler gearwheel on one of the layshafts (40, 50, 38). In particular, a third fixed gearwheel (30) meshes with a third idler gearwheel (62) and a fifth idler gearwheel (64). Especially, the DCT comprises a park-lock.

Description

Dual clutch transmission for a vehicle

Technical Field

The present invention relates to a dual clutch transmission for a vehicle, such as an automobile.

Background

A dual clutch transmission includes two input shafts that are individually connected to and actuated by two clutches. These two clutches are typically combined into a single device, allowing either of the two clutches to be actuated at a time. The two clutches transmit drive torque from the engine to the two input shafts of the dual clutch transmission.

US 6,634,247B 2 discloses a six-speed dual clutch transmission having an electric unit. Such dual clutch transmissions have not been widely used in street-driven automobiles. Problems that have prevented widespread use of dual clutch transmissions include providing a compact, reliable, and fuel efficient dual clutch transmission. Accordingly, there is a need to provide such dual clutch transmissions that are affordable to consumers.

Disclosure of Invention

A Dual Clutch Transmission (DCT) is provided having an inner input shaft and an outer input shaft. The inner input shaft may be solid or hollow. The outer input shaft surrounds a portion of the inner input shaft in a radial direction. The radial direction of the shaft refers to a direction pointing from the central longitudinal axis of the shaft in the radial direction of the shaft.

The DCT includes a first clutch non-rotatably connected to the inner input shaft and a second clutch plate non-rotatably connected to the outer input shaft. For example, the first clutch is fixed to the inner input shaft and the second clutch is fixed to the outer input shaft. Alternatively, the non-rotatable connection may be achieved by a universal joint.

The DCT also includes a first, second, and third layshaft, which are radially spaced from the input shaft. The countershaft is generally parallel to the input shaft. One or more of the layshafts includes one or more pinions for outputting drive torque to the vehicle. Examples of the vehicle include an automobile or a motorcycle. The pinions of the DCT are each meshed with an output gear, such that the output gears transmit torque from the pinions to an output shaft for driving the vehicle.

The DCT has gears disposed on the first countershaft, the second countershaft, the third countershaft, the inner input shaft, and the outer input shaft. The gears include a first gear set, a second gear set, a third gear set, a fourth gear set, a fifth gear set, a sixth gear set, a seventh gear set, and a reverse gear set for providing seven incremental forward gears and one reverse gear, respectively. Typically, the gear is typically mounted coaxially to its carrier shaft. Having the same axis of rotation for the gear and its carrier shaft ensures uniform gear engagement of the gear with adjacent gears on its parallel shaft.

The increasing gears describe an increasing sequence in which the elements follow each other. The gears of the vehicle are typically arranged in successively increasing fashion from first gear to seventh gear. For example, in a vehicle, first gear has a gear ratio (gear ratio) of 2.97: 1. Second gear has a gear ratio of 2.07: 1. Third gear has a gear ratio of 1.43: 1. Fourth gear has a gear ratio of 1.00: 1. Fifth gear has a gear ratio of 0.84: 1. Sixth gear has a gear ratio of 0.56: 1. The last seven gears have a gear ratio of 0.45: 1. Seven gears provide an increasing sequence of output speeds of the transmission for driving a vehicle having a DCT.

The first gear set includes a first fixed gear on the outer input shaft that meshes with a first gear idler gear on one of the layshafts. Similarly, the third gear set includes a third fixed gear on the outer input shaft that meshes with a third gear idler gear on one of the countershafts. The fifth gear set includes a fifth fixed gear on the outer input shaft that meshes with a fifth gear idler gear on one of the layshafts. The seventh gear set includes a seventh fixed gear on the outer input shaft that meshes with a seventh gear idler gear on one of the countershafts.

The second gear set comprises a second fixed gear on the inner input shaft which meshes with a second gear idler gear on one of the layshafts. The fourth gear set includes a fourth fixed gear on the inner input shaft that meshes with a fourth gear idler gear on one of the countershafts. The sixth gear set includes a sixth fixed gear on the inner input shaft that meshes with a sixth gear idler gear on one of the countershafts. The reverse gear set includes a fixed drive gear on one of the input shafts in direct or indirect mesh with a reverse idler gear on one of the layshafts, which includes or carries a pinion gear.

Direct engagement may be provided by two gears in physical contact with each other. Indirect engagement may be provided by one or more intermediate gears which mesh with the fixed drive and reverse gears.

Each of the gear sets includes a coupling device disposed on one of the countershafts to selectively engage one of the gears to its carrier shaft for selecting one of seven incrementally advanced gears and one reverse gear. A shaft bearing the weight of the shaft bearing gear. The third fixed gear meshes with both the third idler gear and the fifth idler gear.

Two coupling means for engaging two gears may form a coupling unit. The coupling unit is also referred to as a double-sided coupling unit or a double-sided synchronizer.

The DCT provides seven forward gears and one reverse gear. The double clutch of the DCT makes gear shifting between odd and even gears quick and efficient, because the gears of odd and even gears are driven by different clutches, respectively. The double meshing arrangement is provided by a third fixed gear on the outer input shaft meshing with a third gear idler gear and a fifth gear idler gear. The dual mesh configuration allows the DCT to be compact, lightweight, and low cost because a fixed gear is eliminated on the input shaft. Reverse gear makes a vehicle with a DCT more operable.

The dual clutch transmission may further include a park lock gear fixed to one of the layshafts for providing a park lock. The secondary shaft with the park lock also carries a pinion for engaging and for locking the differential of the DCT. The differential includes an output gear on an output shaft. The park lock allows a vehicle having the park lock to park at a location, even on a slope, in a safe manner. The parking lock is easy to implement because it is arranged on the secondary shaft carrying the pinion.

A dual clutch transmission may provide two coupling devices that simultaneously engage two of the idler gears of the seven gears, respectively. This process of multiple engagements of two idler gears on different layshafts is referred to as gear preselection. In particular, two idle wheels of two consecutive gears driven by different input shafts of the DCT can be both engaged for shifting from one to the other of the two gears. For example, when only one input shaft receives input torque, the idler gears of third and fourth gears of the DCT may each be engaged to their load carrying weight layshafts by their adjacent coupling devices. Since the input torque from any input shaft is constantly being transmitted to the idler gears of two consecutive gears, there is little or no interruption in the torque flow during the shift. Thus, a dual clutch transmission provides continuous and more efficient torque transfer as compared to the shifting process of a single clutch transmission.

Depending on the application, different input shafts may provide first forward and reverse. For example, the outer input shaft may drive the first gear set and the inner input shaft may drive the reverse gear set. Because the first forward and reverse gears are provided on different input shafts, the two clutches of the DCT allow for efficient shifting between the two input shafts to provide a rocking action. Thus, the strategy of the DCT alternately engaging one of the two input shafts uses first gear and reverse to rapidly drive the vehicle forward and backward without much loss of momentum. The forward and backward swinging of the vehicle can pull the vehicle out of the puddle.

The reverse gear set may also include another reverse gear for providing a second reverse gear in addition to the first reverse gear described above. The other reverse gear is engaged with another fixed drive gear provided on one of the input shafts. One of the two reverse gears provides a powerful and slower reverse gear, while the other reverse gear provides a faster but less powerful reverse gear. The two reverse gears cause some special vehicles, such as the leopard II main warfare tank, to increase their operability and operating efficiency at different speeds.

In addition, different input shafts drive two reverse gears for providing two reverse gears. This strategy makes the interchange between the two reverse gears very fast, achieved only by alternately engaging one of the two clutches of the DCT. In special cases, both reverse gears are driven by the same inner input shaft or by the same outer input shaft. For simpler design and implementation, the two reverse gears are provided on the same countershaft. In one embodiment, the second forward gear and the other reverse gear are driven by different input shafts for providing a swinging motion to pull out a vehicle stuck in mud.

The DCT may also include an eighth gear set for providing an eighth forward gear. The eighth gearset comprises an eighth fixed gearwheel on one of the input shafts in mesh with an eight-gear idler gearwheel on one of the layshafts. Eight speed is useful for some high end cars with more powerful engines to obtain high speed drive. More gears means more choices for the driver.

The sixth fixed gear may also be engaged with an eight speed idler gear. In other words, the DCT can provide two dual-meshing structures. One double meshing structure includes an eighth gear idler gear that meshes with a sixth gear idler gear via a sixth fixed gear that also serves as an eighth fixed gear. The two double meshing configurations eliminate or reduce the drive gears on the input shaft, thereby reducing the weight, cost, and size of the DCT. Further, since the two double engagement structures are provided on the inner input shaft and the outer input shaft, respectively, gear change between the idler gears of these double engagement structures can be efficiently performed by engaging either one of the input shafts using the double clutch.

In the DCT in this application, the distance between one of the layshafts with the low gear and the inner input shaft is larger than the distance between the other layshaft with the high gear and the inner input shaft. The layshaft with the low range gear may be any layshaft. Since the gears of low gears (e.g., first, second or third gears) can be larger than the gears of high gears (e.g., fifth, sixth, seventh or eighth gears), the countershaft with the gear of the high gear can be closer to the input shaft, so that the DCT can be made compact.

In the present application, the DCT may comprise two pinions, mounted on the two layshafts respectively. In another alternative, each of the three layshafts may have a pinion thereon for outputting the torque it carries on the layshaft. A gear or pinion carrier shaft is a shaft that carries the weight of a gear. The pinion may be used as a fixed gear for providing a park lock. In fact, any one of the pinions on the layshaft may be made in or compatible with the parking lock.

Two or more of the first gear idler gear, the second gear idler gear, the third gear idler gear, and the fourth gear idler gear may be provided on the same countershaft. These lower gears transmit a larger torque and thus require a coarser countershaft than a countershaft carrying a higher gear. A thicker layshaft can be more fully utilized when more low gears are mounted on the layshaft. For example, a first gear idler gear, a second gear idler gear, a third gear idler gear, and a fourth gear idler gear may be mounted on the upper layshaft.

Similarly, two or more of the fifth gear idler gear, the sixth gear idler gear, the seventh gear idler gear, and the eighth gear idler gear may be provided on the same countershaft. It is advantageous for the higher gears to be mounted on the same layshaft, as the shafts can be made thinner in order to reduce the cost and size of the dual clutch transmission. For example, the fifth gear idler gear, the sixth gear idler gear, the seventh gear idler gear, and the eighth gear idler gear may be disposed on the same countershaft. More high gears mounted on the same layshaft also provides the possibility of mounting low gears on another shaft. The other shaft can thus be made shorter for carrying a smaller number of gears.

The DCT may also include bearings for supporting the secondary shaft and the input shaft. One or more of the bearings are disposed proximate the pinion gear. Because each pinion outputs the torque of its carrier shaft, support from its adjacent bearings helps to reduce the flexural load of the carrier shaft, minimize the size of the carrier shaft, and improve the accuracy of the pinion meshing for greater efficiency.

One or more of the bearings are disposed adjacent one of the driven gears of the lower range. The bearing of the support shaft is more advantageously arranged close to the low gear. The support shaft can be made thin with less deflection when the bearing is close to the low gear. For example, the bearing may be positioned against a first or second gear idler. Lower gears (such as first, second or third gears) driven gears carry heavier loads and torques, which require more support from bearings in their vicinity.

In this application, a transmission is provided that includes an output gear on an output shaft that meshes with a pinion of a DCT for outputting drive torque to a torque output device. The torque output device may be a differential of the drive train. In motor vehicles, the term drive train, also known as a drive train or power plant, refers to a group of components that generate and transmit power to a road surface, water or air. This includes the engine, transmission, drive shafts, differential and final drive. The final drive may be a drive wheel, a continuous track such as a tank or track type tractor, a propeller or the like. Sometimes the "drive train" is simply referred to as the engine and transmission, including other components (only when they are integral with the transmission). In a trailer or truck, the transmission designates wheels and axles that are separate from the body of the vehicle.

According to the present application, a driveline device having a gearbox is provided. The driveline device includes one or more power sources for generating drive torque. The power source and the drive train are preferably onboard so that the mobility of the vehicle with the drive train arrangement is better.

The power source may include an internal combustion engine. A drive train with an internal combustion engine and a dual clutch transmission is easy to manufacture. Internal combustion engines consume less gasoline to protect the environment. Furthermore, internal combustion engines for other types of fuels may have even less polluting emissions, such as hydrogen fuel.

The power source may also include an electric motor. Electric motors used in hybrid vehicles or electric vehicles result in reduced pollution compared to typical combustion using gasoline. The electric motor may recover braking energy even in generator mode.

In the present application, a vehicle is also provided, comprising a driveline device. Vehicles with a driveline arrangement are efficient in energy usage by using a dual clutch transmission.

The dual clutch transmission enables gear preselection for smooth gear shifting. The two coupling devices can engage simultaneously the idler gear of the current gear and the idler gear of the next successive gear. This allows the next successive gear to be connected quickly and thus in a smoother manner. In particular, two idler gears of two consecutive gears driven by different input shafts of the DCT may be engaged simultaneously. For example, when only one input shaft receives input torque, the idler gears of third and fourth gears of the DCT may each be engaged to their load carrying weight layshafts through their respective coupling devices. One engaged idler gear is directly driven by input torque, and the other engaged idler gear is driven by input torque via a pinion. In this way, there is little or no interruption in torque flow during the shift. Thus, the dual clutch transmission provides continuous and more efficient torque transfer compared to the shift process of other single clutch transmissions.

Drawings

FIG. 1 illustrates a front view of an embodiment of a dual clutch transmission of the present application;

FIG. 2 illustrates a torque flow path for the first gear ratio;

FIG. 3 illustrates a torque flow path for the second gear ratio;

FIG. 4 illustrates a torque flow path for the third gear ratio;

FIG. 5 illustrates a torque flow path for the fourth speed ratio;

FIG. 6 illustrates a torque flow path for the fifth speed ratio;

FIG. 7 illustrates the torque flow path for the six speed ratio;

FIG. 8 illustrates torque flow paths for a seven speed transmission ratio;

FIG. 9 illustrates the torque flow path for the reverse speed ratio;

FIG. 10 shows an assembly of a double-sided linkage with gears adjacent thereto for engagement;

FIG. 11 shows an assembly of a single-sided coupling device with gears adjacent thereto for engagement;

FIG. 12 illustrates an assembly of an idler gear rotatably supported by a shaft on bearings;

FIG. 13 shows an assembly of fixed gears supported on a shaft;

FIG. 14 shows a detailed cross section of a crankshaft of an internal combustion engine according to an embodiment of a dual clutch transmission;

FIG. 15 illustrates a front view of another embodiment of the dual clutch transmission of the present application;

FIG. 16 shows a developed side view of the dual clutch transmission of FIG. 16;

FIG. 17 illustrates a front view of another embodiment of the dual clutch transmission of the present application;

FIG. 18 shows a developed side view of the dual clutch transmission of FIG. 17;

FIG. 19 illustrates a front view of another embodiment of the dual clutch transmission of the present application;

FIG. 20 shows a developed side view of the dual clutch transmission of FIG. 19;

FIG. 21 illustrates a front view of another embodiment of the dual clutch transmission of the present application;

FIG. 22 shows an expanded side view of the dual clutch transmission of FIG. 21, an

FIG. 23 illustrates an alternate front view of a developed side view of the dual clutch transmission of FIG. 18.

Detailed Description

In the following description, embodiments of the present application will be described in detail. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.

FIGS. 1-9 and 11-15 provide detailed descriptions of embodiments of Dual Clutch Transmissions (DCT) of the present application.

Fig. 1 shows a front view of an exemplary embodiment of a dual clutch transmission 1 according to the present application. The DCT 1 includes a reverse idler shaft 38, a larger output gear 12 on an output shaft 14, an upper pinion 41 on an upper layshaft 40, a solid input shaft 20, a hollow input shaft 22, and a lower pinion 51 on a lower layshaft 50.

The input shaft 20 is also referred to as K1. The input shaft 22 is also referred to as K2. The solid input shaft 20 and the hollow input shaft 22 share the same longitudinal axis of rotation and are each connected non-rotatably to the two clutches 8, 10 of the dual clutch transmission 6. The clutches 8, 10 and the double clutch 6 are shown in fig. 15.

The two

pinions

41, 51 are fixed to the upper and

lower layshafts

40, 50, respectively, at their longitudinal axes of rotation. The output gear 12 is also fixed to an output shaft 14 along its axis of rotation. The two

pinions

41, 51 individually mesh with the output gear 12 at different positions of the output gear 12.

The reverse idler shaft 38, the upper counter shaft 40, the

input shafts

20, 22, and the lower counter shaft 50 are disposed parallel to each other with a predetermined distance therebetween. These distances are respectively arranged in radial direction of the axes, as better seen in fig. 2. Other gears are mounted on these shafts according to a predetermined pattern and mesh with each other. The manner in which these gears are mounted and engaged is better seen in the following figures.

Functionally, the gear 12 acts as a ring gear for the differential, which is the carrier for the differential gear. The carrier is accommodated in a housing. The drive shafts for the wheels of the vehicle (not shown in the figures) can be connected to corresponding bevel gears of the differential. Thus, the output shaft 14 actually serves as the shaft of the differential.

Fig. 1 also shows a cutting plane a-a for showing an expanded cross-sectional view through the DCT 1, which sectional view is shown in fig. 2 to 9. The cutting plane A-A passes through the rotational axes of the reverse idler shaft 38, the upper layshaft 40, the

input shafts

20, 22, the lower layshaft 50, and the output shaft 14. One of the purposes of fig. 2 to 9 is to further illustrate the structure and torque flow of the DCT 1.

Fig. 2 shows an expanded view of the DCT, showing the manner of gear mounting, and corresponds to fig. 1.

According to fig. 2, the DCT 1 comprises, from top to bottom, a reverse idler shaft 38, an upper layshaft 40, a hollow input shaft 22, a solid input shaft 20, a lower layshaft 50 and an output shaft 14. The solid input shaft 20 is partially disposed within the hollow input shaft 22. The solid input shaft 20 protrudes out of the hollow input shaft 22 at both ends thereof. The hollow input shaft 22 is mounted to the solid input shaft 20 by a pair of solid shaft bearings 71, the pair of solid shaft bearings 71 being disposed between the solid input shaft 20 and the hollow input shaft 22 at both ends of the hollow input shaft 22. Thus, the two

input shafts

20, 22 are coupled together such that the solid input shaft 20 rotates freely within the hollow input shaft 22. The hollow input shaft 22 surrounds a right portion of the solid input shaft 20, while a left portion of the solid input shaft 20 is exposed outside the hollow input shaft 22. The assembly of the

input shafts

20, 22 is supported on the left by a solid shaft bearing 71 at the projecting end of the solid shaft 20 and on the right by a hollow shaft bearing 72 on the hollow input shaft 22.

As shown in fig. 2, the outer input shaft 22 surrounds a portion of the solid input shaft 20 in a radial direction of the solid input shaft 20. There are four gears mounted on the left exposed portion of the solid input shaft 20. These gears are, from left to right, successively a second fixed gear 30, a reverse fixed gear 34, a fourth fixed gear 31 and a sixth fixed gear 32. The second, reverse, fourth and sixth fixed gears 30, 34, 31, 32 are all coaxially mounted on the solid input shaft 20. On the hollow input shaft 22 mounted on the right portion of the solid input shaft 20, a third-speed fixed pulley 25, a seventh-speed fixed pulley 27, and a first-speed fixed pulley 24 are attached from left to right. The third fixed gear 25 also serves as a fifth fixed gear 26. A second fixed gear 30 is coaxially fixed to the hollow input shaft 22.

An upper layshaft 40 is disposed above the

input shafts

20, 22. There are gears and couplings on the upper layshaft 40, from right to left, including an upper pinion 41, a seven-speed idler 66, a double-sided coupling 80, a five-speed idler 64, a six-speed idler 65, a double-sided coupling 81, and a reverse idler 37. One countershaft bearing 73 is positioned at the left end of the upper countershaft 40 and the other countershaft bearing 73 is positioned between the upper pinion 41 and the seven speed idler 66. The seven-speed idler 66, the five-speed idler 64, the six-speed idler 65, and the reverse idler 37 are each mounted on the upper layshaft 40 by bearings so that these gears rotate freely about the upper layshaft 40. The double-sided coupling device 80 is movable along the upper layshaft 40 to engage or disengage the seven-speed idler 66 or the four-speed idler 64 to the upper layshaft 40. Similarly, the double-sided coupling device 81 is configured to move along the upper layshaft 40 to engage the sixth-gear idler 65 or the reverse idler 37 to the upper layshaft 40. The seventh-speed idler 66 meshes with the seventh-speed fixed pulley 27. The fifth idler gear 64 meshes with the fifth fixed gear 26. The sixth idler 65 meshes with the sixth fixed sheave 32.

The reverse idler shaft 38 is also disposed above the upper layshaft 40. The first reverse gear wheel 35 is fixed to the reverse idler shaft 38 in the middle. An idler shaft bearing 74 supports each end of the reverse idler shaft 38 so that the first reverse gear 35 and the reverse idler shaft 38 rotate freely together. The upper layshaft 40, reverse idler shaft 38 and input shaft 20 are positioned at the apex of the triangle so that the first reverse gear 35 meshes with the reverse fixed gear 34 and reverse idler gear 37.

The lower layshaft 50 is disposed below the

input shafts

20, 22. Mounted on the lower layshaft 50 are a plurality of gears, linkages and bearings, from right to left, including a lower pinion 51, a first gear idler 60, a double sided linkage 83, a third gear idler 62, a park lock 42, a fourth gear idler 63, a double sided linkage 82 and a second gear idler 61. A countershaft bearing 73 is provided between the lower pinion 51 and the first-gear idler 60. Another countershaft bearing 73 is provided near the second-gear idler 61 at the left end of the lower countershaft 50. The lower pinion 51 is fixed on its axis of rotation to the lower layshaft 50. The first-speed idler 60, the third-speed idler 62, the fourth-speed idler 63, and the second-speed idler 61 are mounted on the lower counter shaft 50 through bearings, respectively, so that these gears become idlers and freely rotate around the lower counter shaft 50.

The double-sided coupling 83 is configured to move along the lower countershaft 50 so that it can engage either the first-gear idler 60 or the third-gear idler 62. Similarly, the double-sided coupling device 82 is configured to move along the lower countershaft 50 so that it can engage the fourth-gear idler gear 63 or the second-gear idler gear 61 to the lower countershaft 50, respectively. The first-speed idler 60 meshes with the first-speed fixed wheel 24. The third idler gear 62 meshes with the third fixed gear 25. The fourth-speed idler 63 meshes with the fourth-speed fixed pulley 31. The second-speed idler 61 is engaged with the second-speed fixed wheel 30.

The parking lock 42 includes a fixed gear fixed to the lower sub-shaft 50. When the vehicle having the dual clutch transmission 1 is parked, the parking lock member 42 locks the lower counter shaft 50. The parking lock is provided with a ratchet device having a pawl device with a rack element, a claw or the like. The parking lock 42 holds the lower layshaft 50 and the output shaft 14 against rotation, which thereby prevents the vehicle from moving when it is parked. The function of the parking lock 42 is easy to implement, since it is arranged on the lower layshaft 50 carrying the pinion 51. In general, the park lock 42 may be disposed on any secondary shaft that carries a pinion.

The DCT 1 with a park lock is controlled by a shift lever that is positioned in the cab and is movable by the vehicle operator between positions corresponding to shift ranges, such as park, reverse, neutral, drive, and low. A linear actuation cable is attached at a first end thereof to the shift lever, and movement of the shift lever alternately pushes or pulls the cable to move a transmission mode select lever attached at the other end of the cable. The mode select lever is mechanically coupled to a shift valve in the DCT housing, and movement of the shift valve effects shifting between different gears.

When the gear lever is in the parking position, two related mechanical actuations occur in the DCT 1. First, depending on the clutch system, the mode select lever is moved to disconnect the

input shafts

20, 22 from the engine. Second, the park lock pawl moves into locking engagement with the park lock 39 on the reverse shaft 38 to thereby lock the output shaft 14 against rotation. A linear actuation cable that actuates the mode select lever moves the pawl.

In other words, there are two double meshing structures in the DCT 1. The first dual engagement structure includes the third fixed gear 25 engaged with both the third idler gear 62 and the fifth idler gear 64. The second double engagement structure includes the first reverse gear wheel 35 engaged with both the reverse idler wheel 37 and the reverse fixed wheel 34.

Additionally, fig. 2 shows a distance 56 extending between the

input shafts

20, 22 and the upper layshaft 40, and a distance 58 extending between the

input shafts

20, 22 and the lower layshaft 59.

The distance 56 between the

input shafts

20, 22 and the upper layshaft 40 is measured from the common longitudinal axis of the

input shafts

20, 22 to the longitudinal axis of the upper layshaft 40.

Gears

64, 65, 66 reflecting high gears are provided on the upper counter shaft 40. Similarly, the distance 58 is measured from the common longitudinal axis of the

input shafts

20, 22 to the longitudinal axis of the lower layshaft 50.

Gears

60, 61, 62, 63 reflecting the low gear are provided on the lower counter shaft 50. Because the high range is less than the low range, distance 56 is longer than distance 58.

The output shaft 14 is also disposed below the lower countershaft 50. Two output shaft bearings 75 are respectively mounted at two opposite ends of the output shaft 14 for support. The output gear 12 is coaxially fixed to an output shaft 14. The output gear 12 meshes with the lower pinion 51 and the upper pinion 41.

In this description, the expressions "meshing" and "meshing" (comb) are considered as synonyms with respect to a gearchange wheel or an engaged gear. The solid input shaft 20 is alternatively referred to as the inner input shaft 20, and the hollow input shaft 22 is alternatively referred to as the outer input shaft 22. The solid input shaft 20 is alternatively replaced by a hollow shaft disposed within a hollow input shaft 22. The term "coupling device" is referred to as a "shift mechanism" or "synchronizer" for engaging or disengaging a gear on a shaft. Dual Clutch Transmissions (DCTs) are alternatively referred to as dual clutch, dual clutch transmissions.

The first fixed gear 24 is also referred to as a first fixed gear 24. The third fixed gear 25 is also referred to as a third fixed gear 25. The fifth fixed gear 26 is also referred to as a fifth fixed gear 26. The seventh fixed gear 27 is also referred to as a seventh fixed gear 27. The second fixed gear 30 is also referred to as a second fixed gear 30. The fourth fixed gear 31 is also referred to as a fourth fixed gear 31. The sixth fixed gear 32 is also referred to as a sixth fixed gear 32. The first reverse idler gear 35 is also referred to as a first reverse idler gear 35. The reverse idler gear 37 is also referred to as a reverse idler gear 37. The first-speed idler gear 60 is also referred to as a first-speed idler gear 60. The second-speed idler gear 61 is also referred to as a second-speed idler gear 61. The third idler gear 62 is also referred to as a third idler gear 62. The fourth-gear idler gear 63 is also referred to as a fourth-gear idler gear 63. The fifth idler gear 64 is also referred to as a fifth idler gear 64. The sixth-speed idler gear 65 is also referred to as a sixth-speed idler gear 65. The seventh idler gear 66 is also referred to as a seventh idler gear 66.

In the drawings of the present application, broken lines indicate alternate positions of the components shown or the meshing relationship between the gears.

The DCT 1 allows a shift operation with reduced loss of drive torque. This is because a shift operation selectively connects one of the two clutches 8, 10 of the DCT 1. Thus, an associated additional primary drive clutch may be avoided. This selective connection between the two clutches 8, 10 also enables an automatic gear change which can be achieved without interruption of the propulsion power. The propulsive power includes momentum gained from the rotating gears and rotating shafts within the DCT 1. Such shifting is similar in design to mechanical manual shifting. The dual clutch transmission 1 also provides parallel manual shifting that can be used in a transverse arrangement in a front wheel drive vehicle.

The DCT 1 according to the present application may be similarly connected to a known manual transmission, such as a parallel manual transmission. In the known manual transmission, the drive shaft for the front axle of the vehicle extends outwardly from its DCT case, parallel to the output shaft 14 of the main DCT 1. The known manual transmission arrangements leave less space for the actuation of the manual transmission and the clutch, but also for the optional electric motor. An optional electric motor may be used as a starting device for the internal combustion engine, as an energy recovery device for braking operations or as an additional drive structure in a hybrid vehicle. Having such a small space presents a number of difficulties which are solved or at least alleviated by the present application. The present application provides a DCT 1 having two clutches for connecting to an electric motor and a manual transmission in a compact manner.

The present application provides a compact structure of a parallel transmission. The parallel transmission includes two

input shafts

20, 22, each of which may be non-rotatably coupled via its own clutch to a shaft powered by a driven engine. The DCT 1 of the present application also provides an output shaft 14, the output shaft 14 being parallel to the

input shafts

20, 22.

The DCT 1 according to the present application is particularly suitable for a transverse arrangement of a front wheel drive vehicle, wherein, for example, the front differential is positioned below the

pinions

41, 51. A short overall length of the drive train for transmitting torque can be achieved.

The present application provides at least two

smaller pinions

41, 51 on the intermediately

disposed layshafts

40, 50, which are in meshing engagement with one larger output gear 12. The output gear 12 is in turn fixed to an output shaft 14. This arrangement provides a compact and lightweight DCT 1.

The present application also allows for a design in which the output gear 12 is incorporated into the transmission differential arrangement without providing an intermediate output shaft of the DCT 1. This allows a very compact encapsulation for the DCT 1.

It is also advantageous to provide the fixed gear wheel for the even gears not only on one output shaft, but also to fix the fixed gear wheel for the odd gears to the other output shaft. This arrangement provides the above-described shifting operation in a smooth and efficient manner when shifting is performed successively. This is because the DCT 1 may alternately engage one of the two clutches 8, 10 during upshifts and downshifts. For example, a shift operation from third gear to fourth gear results in solid output shaft 20 and hollow output shaft 22 being alternately engaged, which is energy efficient and fast.

It is advantageous that some of the gears of the lower gears (e.g. first, second, third or fourth gears) are arranged on the same lower layshaft. In fig. 2, the first-gear idler 60, the second-gear idler 61, the third-gear idler 62, and the fourth-gear idler 63 are mounted on the same lower countershaft 50. Conversely, the gear of the high gear (i.e., five, six or seven gears) is provided on the other countershaft. According to fig. 2, a fifth-gear idler 64, a sixth-gear idler 65 and a seventh-gear idler 66 are provided on the upper layshaft 40. This is because the lower countershaft 50 has a lower rotational speed and a larger diameter for higher torque transmission than the upper countershaft 40. This arrangement eliminates the need to provide multiple layshafts of relatively large size to carry the heavy

idler gearwheels

60, 61, 62, 63 of those lower gears (i.e. first, second and third gears), respectively, on different shafts. Further, the reverse idler shaft 38 having an average lower rotational speed, a heavier load, and a smaller gear count can be made shorter and thicker. These arrangements provide flexibility in manufacturing the DCT 1 that is lightweight and low cost.

The countershaft bearing 73 of the DCT 1 is adjacent to the pinion gears 41, 51. The layshaft bearing 73 provides greater support for the

layshaft

40, 50 carrying the pinion gears to reduce undesirable shaft deflection. Excessive shaft deflection may reduce shift efficiency or cause premature gear wear. The idler shaft bearing 74 near the reverse idler shaft 38 also provides a strong support for the first reverse gear 35. In the same way, output shaft bearings 75 at both ends of the output shaft 14 provide firm support for the output shaft 14.

In other words, it is advantageous to provide the first-gear idler 60, the second-gear idler 61, the reverse idler 37 and the

pinions

41, 51 close to the bearings for support. The

pinions

41, 51 and in particular the gears of these low gears (i.e. first and second gears) experience a greater load than the gears of the high gears, so that the transmission ratio is greater for the low and reverse gears. Therefore, the carrier shaft of the low gear (e.g., the lower counter shaft 50) must withstand a high driving force. Shaft bending may be reduced if those forces are experienced at support points near the shaft.

FIG. 2 illustrates a torque flow path for the first gear ratio. In fig. 2, the input torque of first gear is received from a crankshaft 2 of an internal combustion engine (not shown). According to fig. 2, the hollow input shaft 22 of the double clutch 6 of the DCT 1 receives an input torque of first gear. Torque for first gear is transmitted from the hollow input shaft 22, via the first-gear fixed gear 24, via the first-gear idler gear 60, via the double-sided coupling device 83, via the lower countershaft 50, via the lower pinion 51, via the output gear 12, to the output shaft 14. When transmitting first gear torque (providing first gear of DCT 1), the double-sided coupling 83 is engaged to the first gear idler 60. The number of tooth engaged or engaged gear pairs for first gear torque transmission is two.

FIG. 3 illustrates a torque flow path for the second gear ratio. In fig. 3, the input torque of the second gear is received from a crankshaft 2 of an internal combustion engine (not shown). According to fig. 3, the solid input shaft 20 of the double clutch 6 of the DCT 1 receives the input torque of the second gear. Torque for second gear is transmitted from the solid input shaft 20 to the output shaft 14 via the second fixed gear 30, via the second idler gear 61, via the double-sided coupling device 82, via the lower layshaft 50, via the lower pinion 51, via the output gear 12. When transmitting second gear torque (providing second gear of DCT 1), the double-sided coupling 82 is engaged to the second gear idler 61. The number of tooth engaged or engaged gear pairs for torque transmission in second gear is two.

FIG. 4 illustrates the torque flow path for the third gear ratio. In fig. 4, the input torque of third gear is received from the crankshaft 2 of the internal combustion engine (not shown). According to fig. 4, the hollow input shaft 22 of the double clutch 6 of the DCT 1 receives an input torque of third gear. Torque for third gear is transmitted from the hollow input shaft 22, via the third fixed gear 25, via the third idler gear 62, via the double-sided coupling 83, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14. When transmitting third gear torque (providing third gear of DCT 1), the double-sided coupling 83 is engaged to the third gear idler 62. The number of tooth engaged or engaged gear pairs for torque transmission in third gear is two.

FIG. 5 illustrates a torque flow path for the fourth speed ratio. In fig. 5, the input torque of the fourth gear is received from the crankshaft 2 of the internal combustion engine (not shown). According to fig. 5, the solid input shaft 20 of the double clutch 6 of the DCT 1 receives an input torque of fourth gear. Torque for fourth gear is transmitted from solid input shaft 20 to output shaft 14 via fourth gear fixed sheave 31, via fourth gear idler 63, via double-sided coupling 82, via lower layshaft 50, via lower pinion 51, via output gear 12. When transmitting fourth gear torque (providing fourth gear of DCT 1), the double-sided coupling 82 engages the fourth idler gear 63 to the lower layshaft 50. The number of tooth engaged or engaged gear pairs for torque transmission in fourth gear is two.

FIG. 6 illustrates a torque flow path for the fifth speed ratio. In fig. 6, input torque of fifth gear is received from a crankshaft 2 of an internal combustion engine (not shown). According to fig. 6, the hollow input shaft 22 of the double clutch 6 of the DCT 1 receives the input torque of fifth gear. Torque for fifth gear is transmitted from the hollow input shaft 22, via the fifth fixed gear 26, via the fifth idler gear 64, via the double-sided coupling device 80, via the upper layshaft 40, via the upper pinion 41, via the output gear 12, to the output shaft 14. When transmitting fifth gear torque (providing fifth gear of DCT 1), the double-sided coupling 80 is engaged to the fifth idler 64. The number of tooth engaged or engaged gear pairs for torque transmission in fifth gear is two.

FIG. 7 illustrates the torque flow path for the six speed ratio. In fig. 7, input torque for sixth gear is received from a crankshaft 2 of an internal combustion engine (not shown). According to fig. 7, the solid input shaft 20 of the double clutch 6 of the DCT 1 receives an input torque of six gears. Torque for sixth gear is transmitted from the solid input shaft 20 to the output shaft 14 via the sixth fixed gear 32, via the sixth idler gear 65, via the double-sided coupling device 81, via the upper layshaft 40, via the lower pinion 41, via the output gear 12. When transmitting sixth gear torque (providing sixth gear of DCT 1), the double-sided coupling 81 is engaged to the sixth idler 65. The number of tooth engaged or engaged gear pairs for torque transmission in sixth gear is two.

FIG. 8 illustrates torque flow paths for the seven speed transmission ratio. In fig. 8, input torque of seven speeds is received from a crankshaft 2 of an internal combustion engine (not shown). According to fig. 8, the hollow input shaft 22 of the double clutch 6 of the DCT 1 receives an input torque of seven gears. Torque for seven speeds is transmitted from the hollow input shaft 22, via the seven speed fixed gear 27, via the seven speed idler 66, via the double-sided coupling 80, via the upper layshaft 40, via the upper pinion 41, via the output gear 12 to the output shaft 14. When transmitting seven speed torque (providing seven speed of DCT 1), the double-sided coupling 80 is engaged to the seven speed idler 66. The number of tooth engaged or engaged gear pairs for torque transmission in seventh gear is two.

FIG. 9 shows the torque flow path for the reverse speed ratio (first reverse). In fig. 9, the input torque of the reverse gear is received from the crankshaft 2 of the internal combustion engine (not shown). According to fig. 9, the solid input shaft 20 of the double clutch 6 of the DCT 1 receives an input torque in reverse. Reverse torque is transmitted from the solid input shaft 20 via the reverse fixed gear 34 and via the first reverse gear 35. The torque is then transmitted to the output shaft 14 via the reverse idler 37, via the double-sided coupling 81, via the upper layshaft 40, via the upper pinion 41 and via the output gear 12. When reverse torque is transmitted (providing reverse of DCT 1), the double-sided coupling device 81 is engaged to the reverse idler 37. The number of tooth engaged or engaged gear pairs for reverse torque transmission is three.

Fig. 10 shows an assembly 100 of a double-sided coupling device 102 and its

adjacent gears

101, 103 for engagement. The assembly 100 comprises a shaft 104 with two coaxially mounted

idlers

101, 103 on two bearings respectively. A coupling device 102 is provided between the left idler 101 and the right idler 103. The coupling device 102 is configured to move along the shaft 104 to selectively engage either of the

idlers

101, 103 at a time. In other words, the

idlers

101, 103 may alternately be brought into non-rotational engagement with the shaft 104 via the coupling device 102. Symbols for the display assembly 100 are provided on the right hand side of fig. 10.

Fig. 11 shows an assembly 110 of a single-sided coupling device 112 with its adjacent gear 113 for engagement. The assembly 110 includes a shaft 114 having a coaxially mounted idler pulley 113 on bearings. The coupling device 112 is arranged adjacent to the idler wheel 113 on the left side. The coupling device 112 is configured to move along the shaft 114 to engage or disengage the idler pulley 113. In other words, the idler 113 is brought into non-rotational engagement with the shaft 104 by the single-sided linkage 112. Symbols for the display assembly 110 are provided on the right hand side of fig. 11.

Fig. 12 shows assembly 120 with idler gear 121 rotatably supported by shaft 122 on bearings 123. The idler gear 121 is coaxially mounted to the shaft 122 via a bearing 123. Bearing 123 allows idler gear 121 to rotate freely about shaft 122. The symbols of the display assembly 120 are provided on the right hand side of fig. 12.

Fig. 13 shows an assembly 130 supporting a gear 132 fixed on a shaft 131. A fixed gear 132 is coaxially mounted to the shaft 131 such that the gear 132 is fixed to the shaft 131. The fixed gear 132 and the shaft 131 are coupled as a single body so that the torque of the fixed gear 132 is directly transmitted to the shaft 131, and vice versa.

A plurality of fixed gears are fixedly connected to the

input shafts

20, 22 and the

other shafts

12, 38, 40, 50 in a manner similar to the assembly 130. The reference numerals for such fixed gears in the previous figures are provided on the left side in fig. 13. The more commonly used symbols for such fixed gears are provided on the right hand side of fig. 13.

Fig. 14 shows a cross section through a crankshaft 2 of an internal combustion engine according to an embodiment of the DCT 1. According to fig. 14, the crankshaft 2 of an internal combustion engine, not shown here, is non-rotatably connected to the housing 4 of the double clutch 6. The dual clutch 6 comprises an inner clutch disk 8 and an outer clutch disk 10, which are non-rotatably engageable with the housing 4 via a control element, which is not shown here. The solid input shaft 20 is non-rotatably connected to the clutch disc 8 and extends all the way through the hollow shaft 22. Similarly, the hollow input shaft 22 is non-rotatably connected to the other clutch plate 10.

The outer diameter around the inner clutch plate 8 is larger than the outer diameter around the outer clutch plate 10. The outer diameter of the inner clutch plate 8 is thus greater than the outer diameter of the outer clutch plate 10.

Some of the above-described torque flow paths for transferring the DCT 1 may be provided as alternative paths.

The nine torque flow paths described above not only provide a variable scheme to produce the nine gears of the DCT 1, but also provide the possibility of efficiently switching from one gear to another. The gear shift may be achieved between the two input shafts, between gears of the double-meshed structure, or a combination of both.

For example, the DCT 1 may provide odd-numbered gears (i.e., first, third, fifth, and seventh gears) by driving the gears of the DCT 1 using the hollow input shaft 22. The DCT 1 may also provide even-numbered gears (i.e., second, fourth, and sixth gears) by driving the gears of the DCT 1 using the solid input shaft 20. Gear shifting between odd and even numbers can be obtained by alternating between the two

input shafts

20, 22.

A double engagement structure provides efficient and rapid gear shifting between the gears of two driven gears that mesh with a common drive gear. For example, the DCT 1 provides the convenience of selecting third gear or fifth gear without stopping their common drive gear (i.e., the third fixed gear 25). This selection may be achieved by engaging either the driven third idler 62 or the driven fifth idler 64.

The double mesh configuration of the third fixed gear 25, which is commonly engaged by the driven third idler gear 62 and the driven fifth idler gear 64, reduces the number of drive gears. For example, the third fixed gear 25 and the fifth fixed gear 26 are a single gear, and are shared by the third idler gear 62 and the fifth idler gear 64. Therefore, the number of gears on the hollow input shaft 22 has been reduced, and less space is required on the hollow input shaft 22, whereby the DCT 1 is made lighter and cheaper.

The parking lock 42 gives a useful safety structure for a car with a DCT 1. Since the park lock 42 is placed on the lower shaft 50 carrying the final drive pinion 51, the park lock 42 easily holds the lower layshaft 50 and the output shaft 14 against rotation. When the vehicle is in the parking mode, the vehicle with the DCT 1 is prevented from moving.

A smaller number of gear tooth engagements (i.e., gear engagements) is preferred when providing gear mesh or ratcheting for torque transfer. The smaller number of gear tooth engagements provides lower noise and more efficient torque transfer. Examples of fewer gear tooth engagements are provided in fig. 2-10.

The DCT 1 drives the first and reverse gear sets through

different input shafts

20, 22. This provides the ability to drive the vehicle between a slow forward mode and a slow reverse mode by engaging and not engaging the respective clutch 8, 10, which is connected to the two

input shafts

20, 22 respectively. The DCT 1 causes the vehicle to move forward and backward quickly with less loss to transfer power or gear momentum. This is useful in many situations, including when the wheels of the vehicle are immersed in a harsh environment, such as a snow or mud pit. The vehicle can then be freely swung out merely by switching between the two clutches 8, 10 of the DCT 1.

Fig. 16-17 illustrate another embodiment of the present application. This embodiment includes similar components to those of the previous embodiments. Similar parts are marked with the same or similar reference numerals. Descriptions relating to similar components are incorporated herein by reference.

FIG. 15 illustrates a front view of the transmission of the present application. The relatively large output gear 12 meshes with a lower pinion 51 provided on the lower layshaft 50. The output gear 12 also meshes with an upper pinion 41 provided on the upper layshaft 40. The reverse idler shaft 38, solid input shaft 20 and hollow output shaft 22 are disposed in parallel with the upper layshaft 40 and the lower layshaft 50. In some variants of the present application, at least one other layshaft with other pinions may be provided, but this is not shown. Such other pinion gears may then also mesh or mesh with the output gear 12.

Fig. 15 also includes a cutting plane a-a for showing a cross section through the gearbox 1, which is shown in fig. 16. For embodiments with more than two secondary shafts or additional idler shafts, cutting planes leading through all shafts are similarly used. Fig. 16 shows a simplified cross-sectional view through the double-clutch gearbox 1 of fig. 15. The structure and the respective torque flows for a plurality of gears of the double-clutch gearbox 1 are shown.

According to fig. 16, the dual clutch transmission 1 comprises a reverse idler shaft 38, an upper layshaft 40, a solid input shaft 20, a hollow shaft 22 and a lower layshaft 50 from top to bottom. The shafts are arranged in the gearbox 1 parallel to each other at a predetermined mutual distance. A hollow shaft 22 is concentrically disposed about the solid shaft 20. The solid input shaft 20 protrudes out of the hollow input shaft 22 at both ends.

The solid input shaft 20 includes, from the right end to the left end, a solid shaft bearing 71, a hollow shaft bearing 72 that also serves as the solid shaft bearing 71, a sixth-speed fixed gear 32, a fourth-speed fixed gear 31, a second-speed fixed gear 30, and the solid shaft bearing 71.

The hollow input shaft 22 includes, from the right end to the left end, a hollow shaft bearing 72, a first-gear fixed sheave 24, a seventh-gear fixed sheave 27, and a third-gear fixed sheave 25, which also serve as a fifth-gear fixed sheave 26.

The upper layshaft 40 includes, from right to left end, an upper pinion 41, a layshaft bearing 73, a seven-speed idler 66, a double-sided coupling device 80, a five-speed idler 64, a six-speed idler 65, a double-sided connecting device 81, and a reverse idler 37 and layshaft bearing 73. The seventh-gear idle wheel 66 is meshed with the seventh-gear fixed wheel 27. The fifth-speed idler gear 64 meshes with the fifth-speed fixed gear 26. The sixth fixed gear 65 meshes with the sixth idler gear 32.

The reverse idler shaft 38 includes, from the right end to the left end, an idler shaft bearing 74, a first reverse gear 35 meshed with the first reverse gear fixed gear 24, a second reverse gear 36 meshed with the reverse idler gear 37, and the idler shaft bearing 74.

The lower countershaft 50 includes, from right to left end, a lower pinion 51, a countershaft bearing 73, a first-gear idler 60, a double-sided coupling device 83, a third-gear idler 62, a parking lock 42, a fourth-gear idler 63, a double-sided coupling device 82, a second-gear idler 61, and a countershaft bearing 73. Specifically, the first-speed idler 60 meshes with the first-speed fixed pulley 24. The third idler gear 62 meshes with the third fixed gear 25. The fourth-speed idler 63 meshes with the fourth-speed fixed pulley 31. The second-speed idler wheel 61 is meshed with the second-speed fixed wheel 30.

Multiple torque flows for different gears are also possible.

Torque flow for first gear may begin from the hollow input shaft 22, via the first gear fixed gear 24, via the first gear idler 60, via the double-sided coupling 83, via the lower countershaft 50, via the lower pinion 51, and via the output gear 12 to the output shaft 14.

Similarly, torque flow for second gear can start from the solid input shaft 20, via the fixed second gear 30, via the idler second gear 61, via the double-sided coupling 82, via the lower layshaft 50, via the lower pinion 51, and via the output gear 12 to the output shaft 14.

Torque flow for third gear may begin from the hollow input shaft 22, via the third fixed gear 25, via the third idler gear 62, via the double-sided coupling 83, via the lower countershaft 50, via the lower pinion gear 51, via the output gear 12 to the output shaft 14.

Torque flow for fourth gear may begin with solid input shaft 20, via fourth gear fixed gearwheel 31, via fourth gear idler gearwheel 63, via double-sided coupling 82, via lower countershaft 50, via lower pinion 51, via output gear 12 to output shaft 14.

Torque flow for fifth gear may begin from the hollow input shaft 22, via the fifth fixed gear 26, via the fifth idler gear 64, via the double-sided coupling 80, via the upper countershaft 40, via the upper pinion gear 41, and via the output gear 12 to the output shaft 14.

Torque flow for sixth gear may begin with solid input shaft 20, via sixth gear fixed gearwheel 32, via sixth gear idler gearwheel 65, via double-sided coupling 81, via upper countershaft 40, via upper pinion gear 41 and via output gear 12 to output shaft 14.

Torque flow for seven speed can begin from the hollow input shaft 22, via the seven speed fixed gear 27, via the seven speed idler 66, via the double-sided coupling 80, via the upper countershaft 40, via the upper pinion 41 and via the output gear 12 to the output shaft 14.

Reverse torque flow may begin from the neutral input shaft 22, via a first reverse gear stator 24 and via a first reverse gear 35. The torque then goes to the output shaft 14 via the reverse idler shaft 38, via the second reverse gear 36, via the reverse idler 37, via the double-sided coupling 81, via the upper layshaft 40, via the upper pinion 41 and via the output gear 12.

Fig. 17 and 18 show another embodiment of the present application. This embodiment includes similar components to those of the previous embodiments. Similar parts are marked with the same or similar reference numerals. Descriptions relating to similar components are incorporated herein by reference.

Fig. 17 shows a front view of the transmission case 1 of the present application. The relatively large output gear 12 on the output shaft 14 meshes with a lower pinion 51 provided on the lower layshaft 50. The output gear 12 also meshes with an upper pinion 41 provided on the upper layshaft 40. The reverse idler shaft 38, solid input shaft 20, hollow output shaft 22 are disposed in parallel with the upper layshaft 40 and the lower layshaft 50. In some variants of the present application, at least one other layshaft with other pinions may be provided, but this is not shown. Such other pinion gears may then also mesh or mesh with the output gear 12.

Fig. 17 also includes a cutting plane a-a for showing a cross section through the gearbox 1, which is shown in fig. 18. For embodiments with more than two secondary shafts or additional idler shafts, cutting planes leading through all shafts are similarly used.

Fig. 18 shows a simplified cross-sectional view through the double-clutch gearbox 1 of fig. 18. The structure and the respective torque flows for a plurality of gears of the double-clutch gearbox 1 are shown.

The dual clutch transmission 1 includes, from top to bottom, an upper layshaft 40, a solid input shaft 20, a hollow input shaft 22, a lower layshaft 50, and a reverse idler shaft 38.

The shafts are arranged in the gearbox 1 parallel to each other at a predetermined mutual distance. The hollow shaft 22 is concentrically disposed about the solid input shaft 20. The solid input shaft 20 protrudes out of the hollow input shaft 22 at the right end.

The solid input shaft 20 includes, from the right end to the left end, a solid shaft bearing 71, a hollow shaft bearing 72, which also serves as the solid shaft bearing 71, the sixth fixed gear 32, the fourth fixed gear 31, the second fixed gear 30, the solid shaft bearing 71, and the reverse fixed gear 34.

The hollow input shaft 22 includes, from the right end to the left end, a hollow shaft bearing 72, a first-gear fixed sheave 24, a seventh-gear fixed sheave 27, and a third-gear fixed sheave 25, which is also a fifth-gear fixed sheave 26.

The upper counter shaft 40 includes, from right to left, an upper pinion 41, a counter shaft bearing 73, a first-gear idle gear 60 meshed with the first-gear fixed gear 24, a double-sided coupling device 80, a third-gear idle gear 62 meshed with the third-gear fixed gear 25, a fourth-gear idle gear 63 meshed with the fourth-gear fixed gear 31, a double-sided connecting device 81, a second-gear idle gear 61 meshed with the second-gear fixed gear 30, and a counter shaft bearing 73.

The lower countershaft 50 includes, from right to left end, a lower pinion 51, a countershaft bearing 73, a seven-speed idler 66, a double-sided coupling 83, a five-speed idler 64, a six-speed idler 65, a park lock 42, a double-sided coupling 82, a second reverse 36, and a solid shaft bearing 73. Specifically, seven-speed idler 66 is meshed with seven-speed fixed gear 27. The fifth-speed idler gear 64 meshes with the fifth-speed fixed gear 26. The sixth-speed idler 65 meshes with the sixth-speed fixed gear 32.

The reverse idler shaft 38 includes, from the right end to the left end, an idler shaft bearing 74, a first reverse gear 35 and an idler shaft bearing 74 that are meshed with the second reverse gear 36 and the reverse fixed gear 34.

Multiple torque flows are possible.

The torque flow for first gear of fig. 18 can start from the hollow input shaft 22, via the first gear fixed gear 24, via the first gear idler 60, via the double-sided coupling device 80, via the upper layshaft 40, via the upper pinion 41 and via the output gear 12 to the output shaft 14.

Similarly, torque flow for second gear can start from the solid input shaft 20, via the fixed second gear 30, via the idler second gear 61, via the double-sided coupling 81, via the upper layshaft 40, via the upper pinion 41 and via the output gear 12 to the output shaft 14.

Torque flow for third gear may begin from the hollow input shaft 22, via the third fixed gear 25, via the third idler gear 62, via the double-sided coupling 80, via the upper countershaft 40, via the upper pinion gear 41, and via the output gear 12 to the output shaft 14.

Torque flow for fourth gear may begin with solid input shaft 20, via fourth gear fixed gearwheel 31, via fourth gear idler gearwheel 63, via double-sided coupling 81, via upper countershaft 40, via upper pinion 41 and via output gear 12 to output shaft 14.

Torque flow for fifth gear may begin from the hollow input shaft 22, via the fifth fixed gear 26, via the fifth idler gear 64, via the double-sided coupling 83, via the lower countershaft 50, via the lower pinion gear 51, and via the output gear 12 to the output shaft 14.

Torque flow for sixth gear may begin with solid input shaft 20, via sixth gear fixed gearwheel 32, via sixth gear idler gearwheel 65, via double-sided coupling 82, via lower countershaft 50, via lower pinion 51 and via output gear 12 to output shaft 14.

Torque flow for seven speed can begin from the hollow input shaft 22, via the seven speed fixed gear 27, via the seven speed idler 66, via the double-sided coupling 83, via the lower countershaft 50, via the lower pinion 51, and via the output gear 12 to the output shaft 14.

The torque flow for reverse gear may begin with solid input shaft 20, via reverse fixed gear 34, via first reverse gear 35, via second reverse gear 36, via double-sided coupling 82, via lower layshaft 50, via lower pinion 51, and via output gear 12 to output shaft 14.

Fig. 19-20 illustrate another embodiment of the present application. This embodiment includes similar components to those of the previous embodiments. Similar parts are marked with the same or similar reference numerals. Descriptions relating to similar components are incorporated herein by reference.

Fig. 19 shows a front view of the transmission case 1 of the present application. The relatively large output gear 12 meshes with a lower pinion 51 provided on the lower layshaft 50. The output gear 12 also meshes with an upper pinion 41 provided on the upper layshaft 40. There is also a reverse pinion 55 on the reverse solid shaft 38. The reverse hollow shaft 39 is mounted to the reverse solid shaft 38 by two reverse hollow shaft bearings 76 at opposite ends so that the reverse hollow shaft 39 can freely rotate about the reverse solid shaft 38. The reverse pinion 55 also meshes with the output gear 12. The solid input shaft 20 and the hollow input shaft 22 are disposed in parallel with the reverse solid shaft 38, the upper counter shaft 40, and the lower counter shaft 50. In some variants of the present application, at least one other layshaft with other pinions may be provided, but this is not shown. Such other pinion gears may then also mesh or mesh with the output gear 12.

Fig. 19 also includes a cutting plane a-a for showing a cross-section through the gearbox 1, which is shown in fig. 20. For embodiments with more than two secondary shafts or additional idler shafts, cutting planes leading through all shafts are similarly used.

Fig. 20 shows a simplified cross-sectional view through the double-clutch gearbox 1 of fig. 19. The structure and the respective torque flows for a plurality of gears of the double-clutch gearbox 1 are shown.

The dual clutch transmission 1 comprises a reverse idler shaft 38, a reverse hollow shaft 39, an upper layshaft 40, a solid input shaft 20, a hollow input shaft 22, a lower layshaft 50 and an output shaft 14 from top to bottom.

The solid input shaft 20 includes, from the right end to the left end, a solid shaft bearing 71, a hollow shaft bearing 72 that also serves as the solid shaft bearing 71, a fourth-speed fixed gear 31, a second-speed fixed gear 30, a sixth-speed fixed gear 32, and the solid shaft bearing 71.

The hollow input shaft 20 includes, from right to left, a hollow shaft bearing 72, a seventh fixed gear 27 and a third fixed gear 25, which is also a fifth fixed gear 26.

The upper layshaft 40 includes, from right to left end, an upper pinion 41, a layshaft bearing 73, a first-gear idler 60, a double-sided coupling device 80, a third-gear idler 62, an attached third-gear idler 62', a second-gear idler 61, a single-sided connecting device 81, a layshaft bearing 73. The third idler gear 62 meshes with the third fixed gear 25. The second-speed idler wheel 61 is meshed with the second-speed fixed wheel 30. The third-speed idler 62 is attached or welded to the third-speed idler 62' so that they are integrated.

The reverse idler shaft 38 includes, from right to left, a reverse pinion 55, an idler shaft bearing 74, a reverse hollow shaft 39, a parking lock 42, a one-sided coupling 85, and an idler shaft bearing 74.

The reverse hollow shaft 39 includes, from the right end to the left end, a second reverse wheel 36 meshing with a first-speed idler wheel 60 and a first reverse wheel 35 meshing with an attached third-speed idler wheel 62'.

The lower countershaft 50 includes, from right to left end, a lower pinion 51, a countershaft bearing 73, a seven-speed idler 66, a double-sided coupling 83, a five-speed idler 64, a four-speed idler 63, a double-sided coupling 82, a six-speed idler 65, and a countershaft bearing 73. The seventh-gear idle wheel 66 is meshed with the seventh-gear fixed wheel 27. The fifth-speed idler gear 64 meshes with the fifth-speed fixed gear 26. The fourth-speed idler 63 meshes with the fourth-speed fixed pulley 31. The sixth-speed idler 65 meshes with the sixth-speed fixed gear 32.

The torque flow according to first gear of fig. 20 starts from the neutral input shaft 22 via the third fixed gear 25, via the third idler 62, via the attached third idler 62', via the first reverse gear 35. The torque flow then goes through the reverse hollow shaft 39, through the second reverse gear 36, through the first idler gear 60, through the double-sided coupling 80, through the upper layshaft 40, through the upper pinion 41 and through the output gear 12 to the output shaft 14.

The torque flow according to second gear of fig. 20 starts from the solid input shaft 20, via the fixed gear 30, via the idler gear 61, via the single-sided coupling device 81, via the upper layshaft 40, via the upper pinion 41, via the output gear 12 to the output shaft 14.

The torque flow according to third gear of fig. 20 starts from the hollow input shaft 22, via the third fixed gear 25, via the third idler gear 62, via the double-sided coupling device 80, via the upper layshaft 40, via the upper pinion 41, via the output gear 12 to the output shaft 14.

The torque flow according to the fourth gear of fig. 20 starts from the solid input shaft 20, via the fourth fixed gear 31, via the fourth idler gear 63, via the double-sided coupling 82, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to the fifth gear of fig. 20 starts from the hollow input shaft 22, via the fifth fixed gearwheel 26, via the fifth idler gearwheel 64, via the double-sided coupling 83, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to sixth gear of fig. 20 begins with solid input shaft 20, via sixth gear fixed gear 32, via sixth gear idler 65, via double-sided coupling 82, via lower layshaft 50, via lower pinion 51, via output gear 12 to output shaft 14.

The torque flow according to the seventh gear of fig. 20 starts from the hollow input shaft 22, via the seventh fixed gear 27, via the seventh idler 66, via the double-sided coupling 83, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to reverse gear of fig. 20 starts from the hollow input shaft 22, via the third fixed gear 25, via the third idler 62, via the attached third idler 62'. The torque flow is then transmitted via the first reverse wheel 35, via the reverse hollow shaft 39, via the one-sided coupling 85, via the reverse idler shaft 38, via the reverse pinion 55, via the output gear 12 to the output shaft 14.

Fig. 24 and 25 show another embodiment of the present application. This embodiment includes similar components to the previous embodiments. Similar parts carry the same or similar reference numerals. The description relating to similar components is incorporated herein by reference.

FIG. 21 illustrates a front view of the transmission of the present application. The relatively large output gear 12 meshes with a lower pinion 51 provided on the lower layshaft 50. The output gear 12 also meshes with an upper pinion 41 provided on the upper layshaft 40. There is also a reverse pinion 55 on the reverse solid shaft 38. The reverse hollow shaft 39 is mounted to the reverse solid shaft 38 by two reverse hollow shaft bearings 76 at opposite ends so that the reverse hollow shaft 39 can freely rotate about the reverse solid shaft 38. The reverse pinion 55 also meshes with the output gear 12. The solid input shaft 20 and the hollow input shaft 22 are disposed in parallel with the reverse solid shaft 38, the upper counter shaft 40, and the lower counter shaft 50. In some variants of the present application, at least one other layshaft with other pinions may be provided, but this is not shown. Such other pinion gears may then also mesh or mesh with the output gear 12.

Fig. 21 also includes a cut plane a-a for showing a cross-section through the gearbox, which is shown in fig. 21. The structure and the respective torque flows for a plurality of gears of the double-clutch gearbox 1 are shown. For embodiments with more than two secondary shafts or additional idler shafts, cutting planes leading through all shafts are similarly used.

The solid input shaft 20 includes, from the right end to the left end, a solid shaft bearing 71, a hollow shaft bearing 72, a fourth-gear fixed gear 31, a second-gear fixed gear 30, a sixth-gear fixed gear 32, and a solid shaft bearing 71. The hollow shaft bearing 72 also serves as the solid shaft bearing 71. The sixth fixed gear 32 also serves as an eighth fixed gear 32'.

The upper layshaft 40 includes, from right to left end, an upper pinion 41, a layshaft bearing 73, a first-gear idler 60, a double-sided coupling 80, a third-gear idler 62, an attached third-gear idler 62'. Furthermore, the upper layshaft 40 comprises a second-gear idler 61, a double-sided connection 81 ", a sixth-gear idler 65' and a layshaft bearing 73. The third idler gear 62 meshes with the third fixed gear 25. The sixth-speed idler 65' meshes with the sixth-speed fixed gear 32.

The reverse idler shaft 38 includes, from the right end to the left end, a reverse pinion 55, an idler shaft bearing 74, a reverse hollow shaft 39, a one-sided coupling 85, and an idler shaft bearing 74.

The lower countershaft 50 includes, from right to left end, a lower pinion 51, a countershaft bearing 73, a seven-speed idler 66, a double-sided coupling device 83, a five-speed idler 64, a four-speed idler 63, a double-sided coupling device 82, a parking lock 42, an eight-speed idler 67, and a countershaft bearing 73. Specifically, seven-speed idler 66 is meshed with seven-speed fixed gear 27. The fifth-speed idler gear 64 meshes with the fifth-speed fixed gear 26. The fourth-speed idler 63 meshes with the fourth-speed fixed pulley 31. The eight-speed idler 67 meshes with the eight-speed fixed pulley 32'.

The torque flow according to first gear of fig. 22 starts from the hollow input shaft 22, via the third fixed gear 25, via the third idler 62, via the attached third idler 62'. The torque flow is then transmitted to the output shaft 14 via the first reverse gear 35, via the reverse hollow shaft 39, via the second reverse gear 36, via the first idler gear 60, via the double-sided coupling device 80, via the upper layshaft 40, via the upper pinion 41 and via the output gear 12.

Similarly, torque flow according to second gear of fig. 22 begins with solid input shaft 20, via fixed second gear 30, via idler second gear 61, via single-sided coupling 81, via upper layshaft 40, via upper pinion 41, via output gear 12 to output shaft 14.

The torque flow according to third gear of fig. 22 starts from the hollow input shaft 22, via the third fixed gear 25, via the third idler gear 62, via the double-sided coupling device 80, via the upper layshaft 40, via the upper pinion 41, via the output gear 12 to the output shaft 14.

The torque flow according to the fourth gear of fig. 22 starts from the solid input shaft 20, via the fourth fixed gear 31, via the fourth idler gear 63, via the double-sided coupling 82, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to fifth gear of fig. 22 starts from the hollow input shaft 22, via the fifth fixed gearwheel 26, via the fifth idler gearwheel 64, via the double-sided coupling 83, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to sixth gear of fig. 22 starts from the solid input shaft 20, via the sixth fixed gear 32, via the sixth idler gear 65', via the double-sided coupling 81 ", via the upper layshaft 40, via the upper pinion 41, via the output gear 12 to the output shaft 14.

The torque flow according to the seventh gear of fig. 22 starts from the hollow input shaft 22, via the seventh fixed gear 27, via the seventh idler 66, via the double-sided coupling 83, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to the eight speed of fig. 22 begins with the solid input shaft 20, via the eight speed fixed gear 32', via the eight speed idler gear 67, via the double sided coupling 82, via the lower layshaft 50, via the lower pinion 51, via the output gear 12 to the output shaft 14.

The torque flow according to the reverse gear of fig. 22 starts from the hollow input shaft 22 via the third fixed gear 25, via the third idler gear 62, via the attached third idler gear 62', via the first reverse gear 35, via the reverse hollow shaft 39 and via the one-sided coupling 85. The torque flow is then transmitted to the output shaft 14 via the reverse idler shaft 38, via the reverse pinion 55, via the output gear 12.

Fig. 23 shows an alternative front view of the developed side view of the dual clutch transmission 1 of fig. 18. FIG. 23 includes similar components to those of FIG. 1817. Similar parts have similar or identical part reference numerals. Descriptions of similar or identical components are incorporated herein by reference.

While the above description contains many specifics, these should not be construed as limiting the scope of the embodiments, but merely as illustrating the foregoing embodiments. In particular, the above advantages of the present embodiments should not be viewed as limiting the scope of the embodiments, but merely as explaining potential advantages if the embodiments are used in practice. Thus, the scope of the present embodiments should be determined by the claims rather than by the examples given.

Claims

1. A dual clutch transmission (1) comprising:

-an inner input shaft (20) and an outer input shaft (22), at least a portion of the inner input shaft (20) being surrounded by the outer input shaft (22),

-a first clutch disc (8) connected to the inner input shaft (20) and a second clutch disc (10) connected to the outer input shaft (22),

-a first countershaft (40), a second countershaft (50) and a third countershaft (38) spaced apart from the input shafts (20, 22) and arranged parallel to the input shafts (20, 22), at least one of the countershafts (40, 50) comprising a pinion (41, 51) for outputting a drive torque,

-gears arranged on the first countershaft (40), the second countershaft (50), the third countershaft (38), the inner input shaft (20) and the outer input shaft (22), comprising a first gear set, a second gear set, a third gear set, a fourth gear set, a fifth gear set, a sixth gear set, a seventh gear set and a reverse gear set for providing seven incremental forward gears and one reverse gear, respectively,

the first gear set comprises a first fixed gear (24) on the outer input shaft (22) which meshes with a first gear idler gear (60) on one of the layshafts (40, 50, 38),

the third gear set comprises a third fixed gear (25) on the outer input shaft (22) which meshes with a third driven gear (62) on one of the layshafts (40, 50, 38),

the fifth gear set comprises a fifth fixed gear (26) on the outer input shaft (22) which meshes with a fifth gear idler gear (64) on one of the layshafts (40, 50, 38),

the seventh gear set comprises a seventh fixed gear (27) on the outer input shaft (22) which meshes with a seventh gear idler gear (66) on one of the layshafts (40, 50, 38),

the second gear set comprises a second fixed gear (30) on the inner input shaft (20) meshing with a second gear idler gear (61) on one of the layshafts (40, 50, 38),

the fourth gear set comprises a fourth fixed gear (31) on the inner input shaft (20) meshing with a fourth gear idler gear (63) on one of the layshafts (40, 50, 38),

the sixth gear set comprises a sixth fixed gear (32) on the inner input shaft (20) meshing with a sixth gear idler gear (65) on one of the layshafts (40, 50, 38),

the reverse gear set comprises a fixed drive gear (34) on one of the input shafts (20, 22) meshing with a reverse gear (35) on one of the layshafts (40, 50, 38) meshing with a reverse idler gear (37) on the layshaft (40, 50) comprising a pinion (41, 51),

each of the gear sets includes a coupling device disposed on one of the layshafts (40, 50, 38) to selectively engage one of the gears for providing one of seven incremental forward gears and one reverse gear, an

The third fixed gearwheel (25) also meshes with a fifth idler gearwheel (64),

wherein,

the dual clutch transmission (1) further comprises a fixed gear (42) on one of the layshafts (40, 50) carrying a pinion (41, 51) as a final drive for providing a park lock.

2. The dual clutch transmission of claim 1,

it is characterized in that

The first forward and reverse gears are driven by different input shafts (20, 22).

3. Double-clutch transmission (1) according to claim 1,

it is characterized in that

The second reverse gear and the reverse gear are driven by different input shafts (20, 22).

4. Double-clutch transmission according to claim 1,

it is characterized in that the preparation method is characterized in that,

the reverse gear group comprises a reverse gear wheel (35) and a second reverse gear wheel (36) which are arranged on the same reverse gear idler shaft (38), and the reverse gear wheel (35) and the second reverse gear wheel (36) are respectively meshed with two gears on two auxiliary shafts.

5. Double-clutch transmission according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the distance between one of the layshafts (40, 50, 38) with the high gear and the inner input shaft (20) is smaller than the distance between the other layshaft (40, 50, 38) with the low gear and the inner input shaft (20).

6. Double-clutch transmission according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

first, third, fifth and seventh gear idler cogs (60, 62, 64, 66) are driven by the hollow input shaft, and second, fourth and sixth gear idler cogs are driven by the solid input shaft (20).

7. Double-clutch transmission according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

at least two coupling devices are configured to simultaneously engage two of the idler gears (60, 61, 62, 63, 64, 65, 66) to preselect a gear for a gear shift.

8. Double-clutch transmission (1) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

at least two of the first gear idler gear (60), the second gear idler gear (61), the third gear driven gear (25) and the fourth gear idler gear (63) are mounted on the same countershaft.

9. Dual clutch transmission (1) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

at least two of the fifth gear idler gear (64), the sixth gear idler gear (65), and the seventh gear idler gear (66) are mounted on the same countershaft.

10. Double-clutch transmission (1) according to one of the preceding claims, further comprising

Bearings (73, 74) for supporting the layshafts (40, 50), at least one of the bearings (73, 74) being disposed proximate to one of the pinions (41, 51).

11. Gearbox with a dual clutch transmission (1) according to one of the preceding claims, comprising an output gear (12) on an output shaft (14) meshing with a pinion (41, 51) in order to output a driving torque to a torque output device.

12. A drive train device having a gearbox according to claim 11, comprising

At least one power source for generating a drive torque.

13. The power train device according to claim 12,

it is characterized in that the preparation method is characterized in that,

the power source includes an internal combustion engine.

14. The power train device according to claim 12,

it is characterized in that the preparation method is characterized in that,

the power source includes an electric motor.

15. A vehicle comprising a driveline arrangement according to one of claims 12 to 14.