GB2458798A - Dual clutch transmission with downstream gearwheel group - Google Patents

Abstract

A double-clutch transmission (DCT) 1 comprises two input shafts 20, 22 that are connected to two clutch discs. The DCT further comprises a first layshaft 40, a second layshaft 50 and a third downstream layshaft 52 arranged in parallel to the input shafts 20, 22. The downstream layshaft 52 comprises a fixed output pinion 53 for outputting a drive torque to a torque train. Gearwheels of gearwheel groups are mounted on the shafts 20, 22, 38, 40, 50 and each one of the gearwheel groups comprises a coupling device that is arranged on one of the layshafts 40, 50, 52 to selectively engage one of idle gearwheels for selecting forward gears and reverse. A downstream gearwheel group comprises a first downstream idler gearwheel 44 which meshes with a second downstream fixed gearwheel 43, a second downstream idler gearwheel 45 which meshes with a third downstream fixed gearwheel 46 and one of the coupling devices 82 for selectively engaging one of the downstream idler gearwheels 44, 45 to the downstream layshaft 52. Also claimed is a power train device in a vehicle, the power train device comprising a gearbox having the double-clutch transmission and a power source which may be a combustion engine and/or an electric motor.

Description

GM Global Technology Operations, inc.

DObl.-ClUtCh TraiSmJJ�iOfl for Vehiclg! The present application relates to a double-clutch transmis-sion for vehicles, such as cars.

A double-Clutch transmission (DCT) comprises two input shafts that are connected to and are actuated by two clutches sepa- rately. The two clutches are often combined into a single de-vice that permits actuating any of the two clutches at a time. The two clutches are connected to two input shafts of the DCT separately for providing driving torques.

Volkswagen has presented a DCT named DSG DQ200. The DSG 0Q200 is an attempt of having a seven-speed DCT in the cars for street driving. The DCT still has not been widely. Problems that hinder the wide application of DCT comprise of providing : a compact, reliable, and fuel-efficient DCT. Therefore, there *. exists a need far providing such a DCT that consumers can af-ford.

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2 The present application ptovides an improved double-clutch transmission (DCT) that comprises an inner input shaft and an outer input shaft.

The outer input shaft surrounds a portion of the inner input * 30 shaft. The inner input shaft is partially inside the outr input shaft. In other words, the outer input shaft encloses the inner input shaft in a radial direction. The radial di-rection indicates regions that surround a longitudinal axis of the inner input shaft.

In addition, the DCT has a first clutch disc and a second clutch disc. The first clutch disc is connected non-rotatably to the inner input shaft. Similarly, the second clutch disc is also connected non-rotatably to the outer input shaft. The non-rotatably connection allows parts that joined to the non-rotatably connection to rotate together when one of.the parts is subjected to a driving torque. Such a non-rotatáblY con-nection can be provided by a universal joint.

A first layshaft and a second layshaft are spaced apart from the input shafts. These layshafts are arranged in parallel to the input shafts. Longitudinal axes of these shafts are par-allel to each other.

r. The DCT also includes a first gearwheel group, a second gear- wheel group, and a third gearwheel group for transmitting in-put torque from an engine to a differential of a car.

:. The first gearwheel group includes a first fixed gearwheel1 a first idler gearwheel and a first coupling device. In par-* **.

*..: ticular, the first fixed gearwheel is provided on one of the input shafts. The first idler gearwheel and the first cou-pling device are arranged together on the first layshaft. Put differently, the first layshaft supports the first idler gearwheel and the first coupling device. The first idler gearwheel meshes or combines with the first fixed gearwheel whilst the first coupling device selectively engages the first idler gearwheel.

When first coupling device engages the first idler gearwheel, torque from the input shaft that has the first fixed gear-wheel is transmitted via the first idler gearwheel via the first coupling device to the layshaft that is connected to the first coupling device. In this manner, the first gear-wheel group transmits incoming torque and together with other parts of the DCT provides two or more different gears.

In a similar manner, the second gearwheel group and the third gearwheel group are constructed. The gearwheel groups to-gether provide three sequentially increasing gears.

In practise, a double coupling element can act as two cou-pling devices that serve two idler gearwheels. AlternatiVelY, two single coupling elements can act as two coupling devices *that serve two idler gearwheels.

For illustration, consider transmission gears of a car that ::..: are arranged in a sequentiallY increasing manner from a first I..

gear to a seventh gear. A first gear has a gear ratio of 2.97:1. A second gear has a gear ratio of 2.07:1. A third :. gear has a gear ratio of 1.43:1. A fourth gear has a gear ra-tio of 1.00:1. A fifth gear has a gear ratio of 0.84:1. A I. sixth gear has a gear ratio of 0.56:1. A seventh gear has a gear ratio of 0.42:1. With these gear ratios, the gears can provide an increasing order of output speed for driving a car that is equipped with these transmission gears.

In addition, the DCT includes parts for multiplying its transmission speed. The parts includes a downstream gearwheel group that receives an input torque at one rotational speed and further convert the received one rotational speed to two or more rotational speeds. The downstream gearwheel group comprises gearwbeels on the second layshaft that carries the idler gearwheels of the first, the second, and the third gearwheel groups. The downstream gearwheel group further com-prises one or more gearwheela on a third layshaft that is fixed with a pinion. In one embodiment, the downstream gear-wheel group comprises a first downstream fixed gearwheel a second downstream fixed gearwheel, and a third downstream fixed gearwheel.

The first downstream fixed gearwheel is provided on the first layshaft whilst the second downstream fixed gearwheel is pro-vided on the second layshaft. The first downstream fixed gearwheel meshes with the second downstream fixed gearwheel.

The third downstream fixed gearwheel is provided on the sec-and layshaft.

Further, the parts also include a downstream layshaft and a downstream gearwheel group. The downstream layshaft is spaced apart from the input shafts and is arranged in parallel tO c the input shafts. Further, the downstream gearwheel group is :r' arranged on the downstream layshaft. a.

The downstream gearwheel group includes a first downstream a...

: idler gearwheel, a second downstream idler gearwheel1 and a downstream coupling device. The first downstream idler gear-wheel meshes with the second downstream fixed gearwheel. The second downstream idler gearwheel meshes with the third down- stream fixed gearwheel. The downstream coupling device selec-tively engages one of the downstream idler gearwheels.

For outputting a drive torque, the DCT also includes a main pinion, which is arranged on the downstream layshaft. The drive torque can be transmitted to drive train of a vehicle.

The drive train is also referred to as a power train or as a power plant that comprises group of components for deliver-ing power to a road surface, water, or air. The components can include a drive wheel, a continuous track that is used by tanks or caterpillar tractors, or a propeller.

Put differently, the above-described DCT provides six forward gears through dual clutch discs. The DCT makes gear switching between odd and even ratios to be swift and efficient because different clutch discs drive the gearwheels of the odd and even gears respectively. The downstream gearwheel group acts to double the number of gears provided by earlier described structure and thus make the DCT compact and lightweight. As a result, the DCT is easy to manufacture.

The double-clutch transmission device can compriS& a reverse layshaft and a reverse pinion for providing a rever$egear.

*.. The reverse layshaft is spaced apart from the input shafts and it is arranged in parallel to the input shafts whilst the reverse pinion is fixed to the reverse layshaft for output- :r' ting a reverse drive torque.

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Further, the double-Clutch transmission device can comprise a : reverse gearwheel group that includes a reverse idler gear- wheel and a reverse coupling device. The reverse idler gear-wheel and the reverse coupling device are arranged together on the reverse layshaft. In other words, the reverse idler gearwheel and the reverse coupling device are positioned on the reverse layshaft. The reverse idler gearwheel meshes with one of the idler gearwheels. The reverse coupling device acts to engage selectively the reverse idler gearwheel such that the reverses idler gearwheel is fixed to the reverse lay-shaft.

Different input shafts can drive forward gear and a reverse gear to provide a rocking function for retrieving a vehicle that is stuck in mud. The forward gear can include a first gear or a second gear. In particulars the first fixed gear-wheel and the second fixed gearwheel can be provided on the different input shafts and the reverse idler gearwheel meshes with the second idler gearwheel.

Then, the rocking function is produced by the dual clutches of the DCT switching quickly between the forward and the re-verse gear. As a result, the vehicle is driven rapidly back and forth to pull the vehicle out of mud.

The DCT can have configured in different ways. In one con-figuration, the first fixed gearwheel and the third fixed gearwheel are provided on the outer input shaft whilst the second fixed gearwheel is provided on the inner input shaft.

In another configuration, the first fixed gearwheel and the f third fixed gearwheel are provided on the inner input shaft whilst the second fixed gearwheel is provided on the outer input shaft. Further, the first idler gearwheel the second idler gearwheel, and the third idler gearwheel can be pro- vided on the first layshaft.

Moreover, the DCT can include a fourth gearwheel group for providing additional gears. In other words, the DCT with the fourth gearwheel group provides eight forward gears.

The fourth gearwheel group includes a fourth fixed gearwheel, which is provided on one of the input shafts. Further, it in-cludes a fourth idler gearwheel that meshes with the fourth fixed gearwheel. For selectively engagement of the fourth idler gearwheel, a fourth coupling device is also provided.

The fourth idler gearwheel and the fourth coupling device are arranged together on the first layshaft. Put differently, the first idler gearwheel the second idler gearwheel, the third idler gearwheel, and the fourth idler gearwheel are placed on the same first layshaft.

In addition, the fourth gearwheel group can be configured in different ways. In one configuration1 the fourth fixed gear-wheel is provided on the inner input shaft. Alternatively, the fourth fixed gearwheel can also be placed on the outer input shaft. The fourth idler gearwheel can also be provided on the first layshaft.

The double-clutch transmission can comprise a park-lock. The park-lock is provided on the downstream layshaft. The down-.

stream layshaft can include a final drive pinion for engaging and locking a differential of the DCT. The differential corn- prises the output gearwheel on the output shaft. The park- lock thus enables a vehicle with the park-lock to park at a :r place in a secure manner, even on a slope. The park-lock is easy to implement and beneficial for safety of passengers.

The double-clutch transmission can comprise shaft bearings for supporting the inner input shaft and the outer input shaft. Further, one or more of the shaft bearings can be pro-vided at least one end of the inner input shaft and of the outer input shaft. This advantageous prevents the input shafts from bending or deflecting.

Moreover, the double-clutch transmission can include layshaft bearings for supporting the layshafts. One or more of the layshaft bearings can be provided next to the pinion. The pinion can output large torque. Thus, the layshaft that car-ries the pinion is better supported by adjacent layshaft bearing for reducing shaft detlection. This thereby improves torque transmission efficiency nd reduces cost of the DCT.

Similarly, one or more of the remaining layshaft bearings can be provided next to one of the idler gearwheels of low gears.

The gearwheels of low gears transmit larger torques as com-pared to the gearwheels of high gears. Close support of the bearings thus help to reduce excessive deflection of the lay-shaft.

According to the applications a gearbox is provided. The gearbox comprises the DCT and an output gearwheel that is provided on an output shaft. The output gearwheel meshes with thepinions for providing a single source of torque output.

This allows construction of the DCT to be simple and neat.

The application provides a power train device with the above- 2t7 mentioned gearbox. The power train device comprises one or : more power source for generating a driving torque. The power a..

:. train device usually has the gearbox and a power source for the gearbox onboard so that the power train device can be mo- : bile without being attached physically to an external sta- .25: tionary power source.

The power source can include a combustion engine. The power train with the combustion engine and the DCT is easy to manu-facture. The combustion engine can consume less petrol for environmental protection. Furthermore, a combustion engine using other types of fuel, such as hydrogen fuel, can reduce pollution.

Alternatively, the power source can comprise an electric mo- tor. An electric motor used in a hybrid car, or in an elec-trical car enables reduction of pollution1 as compared to typical combustion using petrol1 The electric motor can even operate in a generator mode to recuperate brake energy.

The application provides a vehicle that comprises the above-mentioned power train device. The vehicle having the power train device is efficient in energy usage by use of the DCT.

Fig. 1 illustrates a front view of an embodiment of a dou-ble clutch transmission of the application, Fig. 2 illustrates the path of torque flow of a first gear transmission ratio of the double clutch transmis-sion, Fig. 3 illustrates the path of torque flow of a second gear transmission ratio of the double clutch trans-mission, Fig. 4 illustrates the path of torque flow of a third gear transmission ratio of the double clutch transmis-sion, *:. Fig. 5 illustrates the path of torque flow of a fourth gear transmission ratio of the double clutch trans-S...

.ssion, *:; Fig. 6 illustrates the path of torque flow of a fifth gear transmission ratio of the double clutch transmis-S iOfl, Fig. 7 illustrates the path of torque flow of a sixth gear transmission ratio of the double clutch transmis-sion, Fig. 8 illustrates the path of torque flow of a seventh gear transmission ratio of the double clutch trans-S S IOfl, Fig. 9 illustrates the path of torque flow of an eighth gear transmission ratio of the double clutch trans-mission, Fig. 10 illustrates the path of torque flow of a reverse S gear transmission ratio of the double clutch trans-mission, Fig. 11 illustrates an assembly of a double-sided coupling device of the double clutch transmission for engag-ing its neighbouring gearwheels, Fig. 12 illustrates ai assembly of a single-sided coupling device of the double clutch transmission for en-gagement its neighbouring gearwheel, Fig. 13 illustrates an assembly of an idler gearwheel of the double clutch transmission that is rotatably supported by a shaft via a bearing, Fig. 14 illustrates an assembly of a fixed gearwheel of the double clutch transmission that is supported on a shaft, and Fig. 15 illustrates a cross-section through a crankshaft of an internal combustion engine with of the double clutch transmission. S...

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In the following description, details are provided to de-*5*S scribe the embodiments of the application. It shall be appar-

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ent to one skilled in the art, however, that the embodiments may be practised without such details.

Figs. 1 to 15 provide detailed description of an embodiment of a double clutch transmission (DCT) of the application.

Figs. 1 to 15 have similar parts. The similar parts have same reference number or the same name. The description of the similar parts is thus incorporated by reference. :1.1

Fig. 1 illustrates a front view o an embodiment of a double clutch transmission 1 of the application. The DCT 1 comprises a relatively large output gearwheel 12, a reverse gear idler shaft 38, an input solid shaft 20, an input hollow shaft 22, an upper layshaft 40, a lower laysbaft 50, a bottom layshaft 52, and two pinions 53, 55, The above-mentioned shafts, the reverse gear idler shaft 38, the two input shafts 20, 22, the upper layshaft 40, the lower layshaft 50, and the bottom layshaft 52 are provided parallel to each other at predetermined mutual distances inside DCT 1.

The solid input shaft 20, as provided here, is also called Xl or an inner input shaft whilst the hollow input shaft 22 is also called K2 or an outer input shaft.

In a generic sense, a hollow shaft can replace the solid in- *.,, put shaft 20. That is, the input shaft 20 need not have a ::::.! solid cross-section but can have a hollow centre.

The solid input shaft 20 and the hollow input shaft 22 share *. the same rotational axis and are non-rotatably connected to an inner clutch disc 8 and to an outer clutch disc 10 of a **1 double clutch 6, separately, as seen in Fig. 15. The inner *.21. clutch disc 8 is also known as inner clutch. The outer clutch disc 10 is also known as outer clutch.

The bottom pinion 53 and the reverse pinion 55. The bottom pinion 53 is fixed to a rotational axis of the bottom lay- shaft 52 whilst the reverse pinion 55 is fixed to a rota-tional axis of the reverse gear idler shaft 38. The output gearwheel 12 is fixed to a rotational axis of an output shaft 14. The two pinions 53, 55 mesh or comb with the output gear-wheel 12 separately at different positions of the output gearwheel 12.

The reverse gear idler shaft 38 the two input shafts 20, 22, the upper layshaft 40, the lower layshaft 50, and the bottom layshaft 52 are parallel to each other at predetermined dis-tances. The distances are provided in radial directions of these shafts, which are better seen in Fig. 2. Other gear-wheels are mounted on these shafts respectively meshing with each other according to predetermined manners. The manners of these gearwheels' mounting and meshing are better seen in some of the following figures.

En the specificatiofl the expressions "mesh" and "comb" with respect to geared wheels are provided as synonyms. The ex- pressiorl "double-clutch transmission" can be expressed alter-natively as "double-clutch" or "dual clutch transmissiOn". *..* * S *

.. Fig. 2. further shows a cutting plane A-A for illustrating an b expanded cross-section view through the DCT 1, which is shown in Figs. 2 to 10. The cutting plane A-A passes through the 4, rotational axis of the output gearwheel 12, the rotational axis of the pinion 53, the rotational axis of the lower lay-*5** shaft 50, the rotational axis of the upper layshaft 40, the 2 rotational axis of the input shafts 20, 22, and the rota-tional axis of the pinion 55.

One of the goals of Figs. 2 to 10 is to illustrate further structure and torque flows of the DCT 1.

Fig. 2 illustrates an expanded view of the DCT 1 that shows manners of gearwheel mounting, which correspond to Fig. 1.

The DCT 1 compriseS1 from top to bottom, a reverse gear idler shaft assembly, a solid input shaft assembly, a hollow input shaft assembly, an upper layshaft assembly, a lower layshaft assembly, a bottom layshaft assembly, and an output shaft as-sembly.

In particular. the solid input shaft assembly includes the solid input shaft 20 whilst the hollow input shaft assembly includes the hollow input shaft 22. The reverse gear idler shaft assembly includes the reverse gear idler shaft 38. The upper layshaft assembly comprises the upper layshaft 40. The lower layshaft assembly includes the lower layshaft 50. The bottom layshaft assembly comprises the b5ttom layshaft 52.

The output shaft assembly comprises the output shaft 14.

The hollow shaft 22 is arranged concentrically around the solid input shaft 20. The solid input shaft 20 protrudes out- *,,, side the hollow input shaft 22 at a right end. Put differ- ::::. ently, a central portion of the solid input shaft 20 is sur-O rounded by the outer input shaft 22 in a radial direction of :" the input shafts 20, 22.

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The hollow input shaft 22 is attached onto the solid input S...

shaft 20 via a pair of solid shaft bearings 71 that are posi- tioned at two ends of the hollow input shaft 22. As a result, the two input shafts 20, 22 are coupled such that the solid input shaft 20 is free to rotate inside the hollow input shaft 22. Further, one solid shaft bearing 71 is provided to support a left protruding end of the solid input shaft 20. A hollow shaft bearing 72 is also provided to support a right end of the hollow input shaft 22.

Referring to Fig. 2, the solid input shaft assembly comprises the solid input shaft 20 and a plurality of components that is provided on the solid input shaft 20. The components com-prises, from a right end of the solid input shaft 20 to a left end of the solid input shaft 20, the solid shaft bearing 71, the hollow shaft bearing 72, a fixed wheel eighth gear 28, a fixed wheel second gear 30, and the solid shaft bearing 71. The hollow shaft bearing 72 also serves also as solid shaft bearing 71. The fixed wheel eighth gear 28 serves as a fixed wheel fourth gear 31. The fixed wheel second gear 30 acts a fixed wheel sixth gear 32. The fixed wheel second gear and the fixed wheel eighth gear 28 are fixed coaxially onto the solid input shaft 20.

Referring to Fig. 2, the hollow input shaft assembly the hol-low input shaft 20 and a further plurality of components that are placed on the hollow input shaft 20. The components corn-prises, from a right end of the hollow input shaft 20 to a left end of the hollow input shaft 20, the hollow shaft bear- *0 ing 72, a fixed wheel first gear 24, and a fixed wheel third : gear 25. The fixed wheel first gear 24 serves as a fixed :. wheel fifth gear 26 whilst the fixed wheel third gear 25 serves as a fixed wheel seventh gear 27. Both the fixed wheel S...

first gear 24 and the fixed wheel third gear 25 are fixed co- 4 axially to the hollow input shaft 22.

Referring to Fig. 2, the reverse gear idler shaft assembly comprises the reverse gear idler shaft 38. A plurality of components is placed on the reverse gear idler shaft 38. The components comprises, from the right end to the left end, a reverse pinion 55, a idler shaft bearing 74, a reverse gear idler wheel 37, a single-sided coupling device 83, and an-other idler shaft bearing 74.

The reverse pinion 55 is fixed to the reverse gear idler shaft 38 at its rotational axis. The idler shaft bearings 74 act to support the reverse gear idler shaft 38. The reverse S gear idler wheel 37 is mounted on the reverse gear idler shaft 38 by bearings separately such that the reverse gear idler wheel 37 acts as an idler, being free to rotate around the reverse gear idler shaft 38. The single-sided coupling device 83 is configured to move along the reverse gear idler shaft 38 to engage or disengage the reverse gear idler wheel 37.

Referring to Fig. 2, the upper layshaft assembly includes the upper layshaft 40 and a further plurality of components that is provided on the upper layshaft 40. The components corn- prises, from the right end to the left end, a layshaft bear-ing 73, a fixed wheel upper gear 42, a idler first gear 60, a double-sided coupling device 80, a idler third gear 62, a : idler fourth gear 63, a double-sided coupling device 81, an *2b idler second gear 61, and another layshaft bearing 73. p

** The layshaft bearings 73 are intended to support the upper layshaft 40. The fixed wheel upper gear 42 is fixed coaxially : to the upper layshaft 40. The idler first gear 60, the idler third gear 62, and the idler fourth gear 63 are mounted on the upper layshaft 40 by bearings separately such that the idler first gear 60, the idler third gear 62, and the idler fourth gear 63 act idlers, being free to rotate around the upper layshaft 40. Further, the idler first gear 60 serves as an idler fifth gear 64 and it, combs with the reverse gear idler wheel 37. The idler third gear 62 serves as an idler seventh gear 66 and it combs with the fixed wheel third gear 25. The idler fourth gear 63 serves as idler eighth gear 67 and it combs with the fixed wheel eighth gear 28. The idler second gear 61 serves as an idler sixth gear 65 and it combs with the fixed wheel second gear 30.

The double-sided coupling device 80 is configured to move along the upper layshaft 40 to engage one of the idler first gear 60 and the idler third gear 62 to the upper layshaft 40 or to disengage one of the idler first gear 60 and the idler third gear 62 from the upper layshaft 40. SimilarlY, the dow-ble-sided coupling device 81 is configured to move along the upper layshaft 40 to engage one of the idler fourth gear 63 and the idler second gear 61 to the upper layshaft 40 or to disengage one of the idler fourth gear 63 and the idler sec-ond gear 61 from the upper layshaft 40.

In practise two single-sided coupling devices can replace the double-sided coupling device 80 or the double-sided COU-pling device 81 to perform the same function. S...

2'b Referring to Fig. 2, the lower layshaft assembly comprises the lower layshaft 50 and a further plurality of components *:. that are placed on the lower layshaft 50. The components com- prises, from the right end to the left end, a layshaft bear-*SS* : ing 74, a fixed wheel first lower gear 43, a fixed wheel sec- 2 ond lower gear 46, and another layshaft bearing 74. The lay-shaft bearings 74 act to support the lower layshaft 50. The fixed wheel first lower gear 43 is fixed coaxially to the lower layshaft 50 and it combs with the fixed wheel upper gear 42. The fixed wheel second lower gear 46 is also fixed coaxially to the lower layshaft 50.

Referring to Fig. 2, the bottom layshaft assembly comprise the bottom layshaft 52 and a further plurality of components that are mounted the bottom layshaft 52. The components com-prises. from the right end to the left end, a bottom pinion 53, a layshaft bearing 74, a idler first bottom gear 44, an idler second bottom gear 45, a park-lock wheel 75, and an-other layshaft bearing 74.

In particular, the bottom pinion 53 is fixed to the bottom layshaft 52 at its rotational axis. The layshaft bearings 74 act to support the bottom layshaft 52. The idler first bottom gear 44 is mounted on the bottom layshaft 52 by bearings separately such that the idler first bottom gear 44 acts as an idler, being free to rotate around the bottom layshaft 52.

The idler first bottom gear 44 combs with the fixed wheel first lower gear 43. Likewise, the idler second bottom gear 45 is mounted on the bottom layshaft 52 by bearings sepa-rately such that the idler second bottom gear 45 acts as an idler, being free to rotate around the bottom layshaft 52.

*,, The idler second bottom gear 45 combs with the fixed wheel second lower gear 46. *

The double-sided coupling device 82 is configured to move IS S* :. along the bottom layshaft 52 to engage one of the idler first bottom gear 44 and the idler second bottom gear 45 to the 0** *..: bottom layshaft 52 or to disengage one of the idler first 2i bottom gear 44 and the idler second bottom gear 45 from the bottom layshaft 52.

The park-lock wheel 75 is fixed to the bottom layshaft 52.

The park-lock wheel 75 is part of a park-lock that is used for locking the bottom layshaft 52 when parking a vehicle with the double-clutch transmission 1. The bottom layshaft 52. the park-lock wheel 75 is provided with a ratchet device or with a click device tO lock the bottom layshaft 52. The click device has a rack element, a claw or similar. In a park mode, the park-lock wheel 75 is engaged to lock the output shaft 14, via the lower layshaft 52, via the output gearwheel 12, and thus stopping the output shaft 14 from rotating.

Referring to Fig. 2, the output shaft assembly includes the output shaft 14 and the output gear wheel 12 that is fixed coaxially to the output shaft 14. The output gear wheel 12 combs with the bottom pinion 53 and the reverse pinion 55.

Two output shaft bearings 77 are placed at two opposite ends of the output shaft 14 respectively for supporting the output shaft 14.

Put differently, the DCT 1 has one ouble-meShiflg feature.

The oubie-meShiflg feature comprises that the 43 meshes with the fixed wheel upper gear 42 and the idler first bottom gear 44. The expression "coupling device" can be expressed alter-natively as "shifting mechanism" or as "synchronizers".

*2ô The fixed wheel first gear 24 is also known as a first fixed *r gearwheel. Similarly, the fixed wheel third gear 25 is also S..

known as a third fixed gearwheel. The fixed wheel fifth gear 26 is also known as a fifth fixed gearwheel. The fixed wheel *" seventh gear 27 is also known as a seventh fixed gearwheel.

The fixed wheel eighth gear 28 is also known as a eighth fixed gearwheel. The fixed wheel second gear 30 is also known as a second fixed gearwheel. The fixed wheel fourth gear 31 is also known as a fourth fixed gearwheel. The fixed wheel sixth gear 32 is also known as a si.xth fixed gearwheel.

Moreover, the reverse gear idler wheel 37 is also known as a reverse idler gearwheel. Similarly, the reverse gear idler shaft 38 is also known as a reverse idler gear shaft. :1.9

The idler first gear 60 is also known as a first idler gear-wheel. Similarly, the idlev second gear 61 is also known as a second idler gearwheel. The idler third gear 62 is also known as a third idler gearwheel. The idler fourth gear 63 is also known as a fourth idler gearwheel. The idler fifth gear 64 is also known as a fifth idler gearwheel. The idler sixth gear is also known as a sixth idler gearwheel. The idler sev-enth gear 66 is also known as a seventh idler gearwheel. The idler eighth gear 67 is also known as a eighth idler gear-wheel.

In a generic sense, the input shafts 20 and 22, or the shafts 38, 40, 50, and 52 can be supported by two or more bearings instead of two bearings.

In the drawings of the present application, dash lines mdi- : cate either alternative positions of the illustrated parts or *::::* combing relationship between the gearwheels. S...

* The DCT 1 can be connected similar to a known manual trans- * mission, such as a parallel manual transmission. In the known manual transmission, a drive shaft for a front axle of a ye-S...

hide extends outward from its gearbox case, and parallel to its main gearbox. This arrangement provides little space for actuation of the transmission and clutch, and for an optional electric motor. The optional electric motor can act as a starter device for a combustion engine, as an energy recu-peration device for brake operation, or as an additional drive means in hybrid vehicles. Having such little space pre-sents a number of difficulties that are solved or are at least alleviated by this embodiment.

The DCT 1 has narrow space requirements and can thus be fixed into a structure of a parallel transmission. Further, the DCT 1 has two input shafts that can be connected to two parallel transmissions. The two input shafts can be non-rotatablY cou-pled via its own clutch to a shaft that is powered by a drive engine. The DCT 1 further may provide an output shaft that is parallel to the input shaft.

The DCT 1 is also particularly well suited for transverse in-stallation in front-wheel drive vehicles, in which the front differential, for example, can be positioned below the pin-ions 51, 55. A short overall length of the power train for transmitting torques can thus be achieved.

The embodiment provides at least two relatively small pinions 53, 55 on intermediately arranged layshafts 52, 38 that comb with one relatively big output gearwheel 12. The output gear-S...

: wheel 12 in turn is fixed to the output shaft 14. This ar- *::::* rangement provides a compact and lightweight DCT 1. S...

The embodiment further allows a design in which the output * gearwheel 12 is integrated into a transmission differential :" device without providing an intermediate output shaft of the DCT1. * S S * ..

This further allows a design in which the output gearwheel is integrated into a transmission differential device without providing an intermediate output shaft of the transmission gearbox. This allows a very dense packaging situation for the gearbox device.

The fixed wheels are arrangement in a manner that support an energy efficient operation. The fixed wheels for even gear- wheels are provided on one input shaft whilst fixed gear-wheels for odd gears on another input shaft. This arrangement allows gears to shift sequentially in a smooth. When the DCT 1 is engaged with or connected to in a particular gear, the next sequential gear in either an increasing mode or a de- creasing mode can be positioned for a rapid and smooth trans-fer or gear change.

The shafts 38 and 52 have reduced shaft deflection as the layshaft bearings 74 are positioned next to the piriions 53, 55, which bear much load. Further, the bearings 71, 72, or 73 are placed at ends of the shafts 20, 22, 38, 40, 50, and 52 for similar reasons.

Figs. 2 to io illustrate torque flow for different gear transmission ratio. A combustiOn engine, which is not shown, transmits an input torque to the DCT 1. * * * IS *

*:::* Fig. 2 illustrates a path of torque flow of a first gear transmiSsion ratio. The hollow input shaft 22 receiveS the *** *.: input torque. As shown in Fig. 2, the torque is then trans- iuitted via the fixed wheel first gear 24, via the idler first *: gear 60, and via the double-Sided coupling device 80. The **.* **. : double-sided coupling device 80 is engaged with or is con- * 2 nected to the idler first gear 60. The torque is later trans-mitted via the upper layshaft 40, via the fixed wheel upper gear 42, via the fixed wheel first lower gear 43, via the lower layshaft 50, via the fixed wheel second lower gear 46, via the idler second bottom gear 45, and via the double-sided coupling device 82. The double-sided coupling device 82 is engaged with the idler second bottom gear 45. The torque is afterward transmitted via the bottom layshaft 52, via the bottom pinion 53, via the output gearwheel 12, and to the output shaft 14. Thus, the number of tooth engagements or connected gear pairs for the torque transfer of the first gear is four.

Fig. 3 illustrates a path of torque flow of a second gear transmission ratio. The solid input shaft 20 receives the in-put torque. The torque is then transmitted via the fixed wheel second gear 30, via the idler second gear 61, and via the double-sided coupling device 81. The double-sided cou-pling device 81 is engaged with or is connected to the idler second gear 61. The input torque is later transmitted via the upper layshaft 40, via the fixed wheel upper gear 42, via the fixed the wheel first lower gear 43, via the lower layshaft 50, via the fixed wheel second lower gear 46, via the idler second bottom gear 45, and via the double-sided coupling de-vice 82. The double-sided coupling device 82 is engaged with the idler second bottom gear 45. Afterward, the input torque *...

: is sent via the bottom layshaft 52, via the bottom jflOfl 53, *. via the output gearwheel 12, and to the output shaft 14.

2 Hence, the number of tooth engagements for the torque trans-fer of the second gear is four. U..

U

*:* Fig. 4 illustrates a path of torque flow of a third gear transmission ratio. The hollow input shaft 22 receives the input torque. The torque is then transmitted via the fixed wheel third gear 25, via the idler third gear 62, via the double-sided coupling device 80. The double-sided coupling device 80 is engaged with or is connected to the idler third gear 62. AfterwardS, the torque i8 transmitted via the upper layshaft 40, via the fixed wheel upper gear 42, via the fixed wheel first lower gear 43, via the lower layshaft 50, via the fixed wheel second lower gear 46, via the idler second bottom gear 45, and via the double-sided coupling device 82. The double-sided coupling device 82 is engaged with the idler second bottom gear 45. The torque is later transmitted via the bottom layshaft 52, via the bottom pinion 53, via the output gearwheel 12, and to the output shaft 14. In total, the number of tooth engagements for the torque transfer of the third gear is four.

Fig. 5 illustrates a path of torque flow of a fourth gear transmission ratio. The solid input shaft 20 receives the in-put torque. The torque is then transmitted via-the fixed wheel fourth gear 31, via the idler fourth gear 63, and via the double-sided coupling device 81. The double-sided cou-pling device 81 is engaged with or is connected to the idler fourth gear 63. The input torque is later transmitted via the upper layshaft 40, via the fixed wheel upper gear 42, via the fixed wheel first lower gear 43, via the lower layshaft 50, via the fixed wheel second lower gear 46, via the idler sec- *: orid bottom gear 45, and via the double-sided coupling device *::* 82. The double-sided coupling device 82 is engaged with or is connected to the idler second bottom gear 45. Afterward the S...

: input torque is transmitted via the bottom layshaft 52, via : the bottom pinion 53, via the output gearwheel 12, and to the output shaft 14. Thus, the number of tooth engagements for the torque transfer of the fourth gear is four.

Fig. 6 illustrates a path of torque flow of a fifth gear transmission ratio. The hollow input shaft 22 receiveS the input torque. The torque is then transmitted via the fixed wheel first gear 24, via the idler first gear 60, via the double-sided coupling device 80. The double-sided coupling device 80 is engaged with or is connected to the idler first gear 60. The input torque is afterward transmitted via the upper layshaft 40, via the fixed wheel upper gear 42, via the fixed wheel first lower gear 43, via the idler first bottom gear 44, and via the double-Sided coupling device 82. The double-sided coupling device 82 is engaged with the idler first bottom gear 44. Later, the input torque is sent via the bottom layshaft 52, via the bottom pinion 53, via the output gearwheel 12, and to the output shaft 14. Hence, the number of tooth engagements for the torque transfer of the fifth gear is four.

3.0 Fig. 7 illustrates a path of torque flow of a sixth gear transmission ratio. The solid input shaft 20 receives the in-put torque. The torque is then transmitted via the fixed wheel second gear 30, via the idler second gear 61, and via the double-sided coupling device 81. The double-sided COU-pling device 81 is engaged with or is connected to the idler second gear 61. Later, the input torque is sent via the upper layshaft 40, via the fixed wheel upper gear 42, via the fixed . : wheel first lower gear 43, via the idler first bottom gear ** 44, and via the double-sided coupling device 82. The double- sided coupling device 82 is engaged with the idler first bot-tom gear 44. The input torque is afterward transmitted via * the bottom layshaft 52, via the bottom pinion 53, via the *: output gearwheel 12, and to the output shaft 14. Thus, the **** number of tooth engagements for the torque transfer of the fifth gear is four.

Fig. 8 illustrates a path of torque flow of a seventh gear transmission ratio. The hollow input shaft 22 receives the input torque. The torque is then transmitted via the fixed wheel third gear 25, via the idler third gear 62, and via the double-sided coupling device 80. The double-sided coupling device 80 is engaged with or is connected to the idler third gear 62. The input torque is later sent via the upper lay-shaft 40, via the fixed wheel upper gear 42, via the fixed wheel first lower gear 43, via the idler first bottom gear 44, and via the double-sided coupling device 82. The double- sided coupling device 82 i8 engaged with the idler first bot-tom gear 44. Afterward, the input torque is transmitted via the bottom layshaft 52, via the bottom pinion 53, via the output gearwheel 12, and to the output shaft 14. Hence, the number of tooth engagements for the torque transfer of the seventh gear is four.

Fig. 9 illustrates a path of torque flow of an eighth seventh gear transmission ratio. The solid input shaft 20 receives the input torque. The torque is then transmitted via the fixed wheel fourth gear 31, via the idler fourth gear 63, and via the double-sided coupling device 81. The double-sided coupling device 81 is engaged with or is connected to the idler fourth gear 63. The input torque is afterward transmit- ..: ted via the upper layshaft 40, via the fixed wheel upper gear *.,* 42, via the fixed wheel first lower gear 43, via the idler *29 first bottom gear 44, and via the double-sided coupling de-vice 82. The double-sided coupling device 82 is engaged with * the idler first bottom gear 44. Later, the input torque is *:" sent via the bottom layshaft 52, via the bottom pinion 53, via the output gearwheel 12, and to the output shaft 14.

Hence, the number of tooth engagements or the torque trans-fer of the eighth gear is four.

Fig. io illustrates a path of torque flow of a reverse gear transmission ratio. The hollow input shaft 22 receives the input torque. The torque is then transmitted via the first fixed wheel first gear 24, via the idler first gear 60, vi the reverse gear idler wheel 37, and via the single-sided coupling device 83. The single-sided coupling device 83 is engaged with or is connected to the reverse gear idler wheel 37. The input torque is afterward transmitted via the reverse gear idler shaft 38, to the reverse pinion 55, via the output gearwheel 12, and to the output shaft 14. Thus, the number of tooth engagements f or the torque transfer of the reverse gear is two.

Fig. ii illustrates an assembly 100 of a double-sided cou- pling device 102 for engaging with its neighbouring gear-wheels 101, 103. The assembly ioo comprises a shaft 104 with the two coaxially mounted idler gears 101, 103 that are placed on two bearings respectively. The coupling device 102 is provided between the idler gear 101 on the left and the idler gear 103 on the right. The coupling device 102 is con-figured to move along the shaft 104 to selectively engage any of the idler gears 101, 103 at one time. In other words, the idler gears 101, 103 can alternatively be brought into non-* S..

: rotating engagement with the shaft 104 by the coupling device *::::* 102. Symbols for showing the assembly 100 is provided at the ?.0. right hand side of Fig. 11. S...

S *e.

* Fig. 12 illustrates an assemblY 110 of a single-sided cou- : pling device 112 for engaging with its neighbouring gearwheel S...

*:*. 113. The assembly 110 is placed on the left hand side of the Fig. 12 whilst symbols for showing the assemblY 110 are pro-vided at the right hand side of Fig. 12. The assembly 110 comprises a shaft 114 with the one coaxially mounted idler gear 113 that is mounted on a bearing. The coupling device 112 is provided next to the idler gear 113 and is placed on the left side of the idler gear 113. The coupling device 112 is configured to move along the shaft 114 to engage or to disengage the idler gears 113. In other words, the idler gear 113 can be brought into non-rotating engagement with the shaft 114 by the single-sided coupling device 112.

Fig. 13 illustrateS an assembly 120 of an idler gearwheel 121 that is rotatably supported by a ehaft 122. The assemblY 120 is provided at the left hand side of the Fig. 13 whilst sym-bols that represent the assembly 120 are provided at the right hand side of the Fig. 13. The idler gearwheel 121 is coaxiallY mounted onto the shaft 122 via a bearing 123. The bearing 123 enables the idler gearwheel 121 to be freely ro-tated around the shaft 122.

Fig. 14 illustrates an assemblY 130 of a fixed gearwheel 132 that is supported on a shaft 131. The fixed gearwheel 132 is coaxially mounted onto the shaft 131 such that the gearwheel 132 is fixed to the shaft 132. The fixed gearwheel 132 and the shaft 131 are joined as one single body such that a : torque of the fixed gearwheel 132 is transmitted to the shaft *. 131 directlY and vice versa.

A number of fixed gearwheelS are rigidly connected to the in-I. * put shafts 20, or 22 or other shafts 14, 38, 40, or 50. A symbol as used in the previous figures for such a fixed gear-**** wheel is provided on the left side in Fig. 14. The more corn-monly used symbol for such a fixed gearwheel is provided on the right side in Fig. 14.

Fig. 15 illustrates a cross-section through a crankshaft 2 of an internal combustiOfl engine according to the embodiment of the DCT 1. The combustion engine is not shown in Fig. 15. Ac-cording to Fig. 15, a crankshaft 2 of an internal combustion engine is non-rotatablY connected to the housing 4 of a dou-ble clutch 6. The double clutch 6 includes an inner clutch disc 8 and an outer clutch disc 10, which can be brought into non-rotating engagement with the housing 4 via control ele-ments that are not illustrated 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 hol-low input shaft 22 is non-rotatably connected to the other clutch disc 10.

An outer diameter around the inner clutch disc 8 is larger than an outer diameter around the outer clutch disc 10. Cor-respondinglY, an outer diameter of the inner clutch disc 8 is larger than an outer diameter of the outer clutch disc 10.

The above-mentioned nine torque flow paths not only provide viable solutions to generate nine gears of the DCT 1, but also offer possibilities of switching from one gear to the another gear in an efficient manner. I... * ** I. *

*:::* The gear switching can be achieved by selecting between the **0 two input shafts and by selecting the appropriate coupling 1W device. For example, the DCT 1 can provide odd gears, that II.

* are the first, third, fifth, and seventh gears, by driving using the hollow input shaft 22. AlternativelY, the DCT 1 can I...

provide even gears, that are the second, fourth, sixth, and eighth gears, by driving the solid input shaft 20.

This manner of gear switching provides gearshift operations with less loss of driving torque. This is because the gear-shift operations can be achieved by selectively connecting one of the two clutch discs 8, 10 of the DCT 1. Therefore, an associated additional main drive clutch can be avoided. Se-lective connections between the two clutch discs 8, 10 also enable the realization of an automatic transmission that can be operated without interruptions in propulsive power. The propulsive power comprises momentum derived from the rotating gearwheels and shafts inside the DCT 1. Such a transmission is similar in design to a mechanical manual transmission and it has correspondingly very low friction losses. The DCT 1 further provides a parallel manual transmission that can be used for transverse installation in a front-wheel drive vehi-cle.

Further, the DCT1 has relatively less number of gear tooth engagement for low noise and efficient torque transmission.

The DCT 1 functions as a group transmission or gearbox that has a main transmission group, an upstream transmission group, and a downstream transmission group.

In particular, the solid input shaft assembly and the hollow .. : input shaft assembly acts as the upstream transmission group.

*::::* The upper layshaft assembly and the lower layshaft assembly act as the main transmission group. The bottom pinion assem-bly acting as an downstream transmission group that enables * two gear ratio ranges, wherein the number of speeds of the DCT 1 is doubled. The double-sided coupling device 82 selec-tively engaging with the idler first bottom gear 44 or with the idler second bottom gear 45 achieves the doubling of transmission speed.

The doubling of transmission speed allows the DCT 1 to take up less space and the DCT 1 to be lightweight as well as eco-nomical to manufacture.

Although the above description contains much specificity.

these should not be construed as limiting the scope of the embodiments but merely providing illustration of the foresee-able embodiments. Especially the above stated advantages of the embodiments should not be construed as limiting the scope of the embodiments but merely to explain possible achieve-ments if the described embodiments are put into practise.

Thus, the scope of the embodiments should be determined by the claims, rather than by the examples given. I.,. * .* *. * * . Is I.

S I.'.

I I..

S *5SS

S I... I5 S S.

I II 31.

Part Reference Number 1 double clutch transmission gearbox 11 2 crankshaft 4 clutch housing 6 double clutch 8 clutch disc clutch disc 12 output gear wheel 14 output shaft solid input shaft 22 hollow input shaft 24 fixed wheel first gear fixed wheel third gear 26 fixed wheel fifth gear 27 fixed wheel seventh gear 28 fixed wheel eighth gear a...

.. 30 fixed wheel second gear a..

31 fixed wheel fourth gear I.?P 32 fixed wheel sixth gear 37 reverse gear idler wheel S..

* 38 reverse gear idler shaft upper layshaft p...

42 fixed wheel upper gear 43 fixed wheel first lower gear 44 idler first bottom gear idler second bottom gear 46 fixed wheel second lower gear lower layshaft 52 bottom layshaft 53 bottom pinion reverse pinion idler first gear 61 idler second gear 62 idler third gear 63 idler fourth gear 64 idler fifth gear 65 idler sixth gear 66 idler seventh gear 67 idler eighth gear 7]. solid shaft bearing 72 hollow shaft bearing 73 layshaft bearing 74 idler shaft bearing park-lock wheel 77 output shaft bearing double-sided coupling device 81 double-sided coupling device 82 double-sided coupling device 83 single-sided coupling device * : 100 double-sided coupling device assembly *::::* ioi idler gear 102 coupling device 103 idler gear S..

* 104 shaft iio single-sided coupling device assemblY **5* *. : 112 coupling device * 25 113 idler gear 114 shaft idler gearwheel assembly 121 idler gear 122 shaft 123 bearing fixed gearwheel assembly 131 shaft 132 fixed gearwheel

Claims (14)

1. CLAIMS1. Double-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) being connected to the in-ner input shaft (20) and a second clutch disc (10) being connected to the outer input shaft (22), -a first layshaft (40) and a second layshaft (50) which are spaced apart from the input shafts (20, 22) and which are arranged in parallel to the input shifts (20, 22), -a first gearwheel group comprises -a first fixed gearwheel (24) which is provided on one of the input shafts (20, * ** 22), -a first idler gearwheel (60) meshing with the first fixed gearwheel (24), and -a first coupling device (80) to selec- * tively engage the first idler gearwheel (60), the first idler gearwheel (60) and the first coupling device (80) being ar-ranged together on the first layshaft (40) -a second gearwheel group comprises -a second fixed gearwheel (30) which is provided on one of the input shafts (20, 22), -a second idler gearwheel (61) meshing with the second fixed gearwheel (30), and -a second coupling device (81) to selec-tively engage the second idler gearwheel (61), the second idler gearwheel (61) and the second coupling device (81) being ar-ranged together on the first layshaft (40), and -a third gearwheel group comprises -a third fixed gearwheel (25) which is provided on one of the input shafts (20, 22), -a third idler gearwheel (62) meshing with the third fixed gearwheel (25), and -a third coupling device (80) to selec-tively engage the third idler gearwheel (62), the third idler gearwheel (62) and the third coupling device (80) being ar-ranged together on the first layshaft (40) wherein *.... : the double-clutch transmissiOn (1) further comprising -a first downstream fixed gearwheel (42) which is provided on the first layshaft (40), -a second downstream fixed gearwheel (43) which is * provided on the second layshaft (50), *: the first downstream fixed gearwheel (42) meshes ** with the second downstream fixed gearwheel (43), * ** -a third downstream fixed gearwheel (46) which is provided on the second layshaft (SO), -a downstream layshaft (52) which is spaced apart from the input shafts (20, 22) and which is ar-ranged in parallel to the input shafts (20, 22) -a downstream gearwheel group which is arranged on the downstream layshaft (52), the downstream gearwheel group comprising -a first downstream idler gearwheel (44) which meshes with the second downstream fixed gear-wheel (43) -a second downstream idler gearwheel (45) which meshes with the third downstream fixed gear-wheel (46), and -a downstream coupling device (82) to selec-tively engage one of the downstream idler gearwheels (44, 45), and -a main pinion (53) which is arranged on the down-stream layshaft (52) for outputting a drive torque.
2. 2. Double-clutch transmission device (1) of claim 1 further comprising -a reverse layshaft (38) which is spaced apart from the input shafts (20, 22) and which is arranged in parallel to the input shafts (20, 22) and -a reverse gearwheel group comprising .. : -a reverse idler gearwheel (37) meshing with one of the idler gearwheels (60, 61, 62) and -a reverse coupling device (83) to selectively engage the reverse idler gearwheel (37), I..* the reverse idler gearwheel (37) and the re- verse coupling device (83) are arranged to-gether on the reverse layshaft (38), and -a reverse pinion (55) which is fixed to the reverse layshaft (38) for outputting a reverse drive torque.
3. 3. Double-clutch transmission device (1) of claim 1 or 2 characteriSed in that the first fixed gearwheel (24) and the third fixed gear-wheel (25) are provided on the outer input shaft (22) and the second fixed gearwheel (30) is provided on the inner input shaft (20),
4. 4. Double-clutch transmission device (1) of claim 1 or 2 characteriSed in that 2.0 the first fixed gearwheel (24) and the third fixed gear-wheel (25) are provided on the inner input shaft (20) and the second fixed gearwheel (30) is provided on the outer input shaft (22).
5. 5. Double-clutch transmission device (1) of claimS 1 to 2 characterised in that the first fixed gearwheel (24) and the second fixed * gearwheel (30) are provided on the different input *.S. shafts (20, 22), and the reverse idler gearwheel (37) meshes with the second idler gearwheels (61). I..S 5. *5S*S S... S. S * us * *.
6. 6. Double-clutch transmission device (1.) of one of afore-mentioned claims further comprises a fourth gearwheel group, the fourth gearwheel group comprises -a fourth fixed geazwheel (31) which is provided on one of the input shafts (20, 22), -a fourth idler gearwheel (63) meshing with the fourth fixed gearwheel (31), and -a fourth coupling device (81) to selectively engage io the fourth idler gearwheel (63), the fourth idler gearwheel (63) and the fourth cou-pling device (81) being arranged together on one the first layshaft (40).
7. 7. Double-clutch transmission device (1) of claim 6 characterised in that the fourth fixed gearwheel (31) is provided on the inner input shaft (20). * ** * *D' 8. Double-clutch transmission device (1) claim 6 characterised in that the fourth fixed gearwheel (31) is provided on the outer **.* input shaft (22). *.
8. S.S S...
9. 9. Double-clutch transmission (1) of one of the af ore-* SI mentioned claims further comprising layshaft bearings (73, 74) for supporting the layshafts (38, 40, 50, 52), at least one of the layshaft bearings (74) being provided next to the pinion (53, 55) and at least another of the layshaft bearings (74) being provided next to one of the idler gearwheels of low gears (60, 61)
10. 10. Double-clutch transmission device (1) of one of the aforementioned claims further comprising a park-lock (75), the park-lock (75) being provided on the downstream layshaft (52)
11. 11. Gearbox comprising -a double-clutch transmission (1) of one of afore-mentioned claims and -an output gearwheel (12) which is provided on an output shaft (14), the output gearwheel (12) mesh-ing with the pinions (53, 55).
12. 12. Power train device with a gearbox of claim 1]. comprising at least one power source for generating a driving torque.
13. 13. Power train device of claim 12, characterised in that S... : the power source comprises a combustion engine. 2 r14. Power train device of claim 12 or 13, S...characterised in that S..* the power source comprises an electric motor. p... p p..."2 15. Vehicle comprising * 55 the power train device of one of the claims 12 to
14. 14.