Abstract:
A motor vehicle transmission ( 1 ) which is outfitted with a start-up subassembly (A), a core transmission (B) as well as an output subassembly (C) which are drive-engineering connected with one another and are arranged in a transmission housing to reduce development, manufacturing and storage costs. Moreover, the start-up subassembly (A) contains a clutch, a double clutch ( 5 ) or a torque converter, while the core transmission (B) is constructed as a gear reduction transmission. The core transmission (B) disposes over at least one transmission input shaft ( 6, 7 ), a gear reduction shaft ( 19 ) as well as at least one transmission output which is not oriented coaxially toward the at least one transmission input shaft ( 6, 7 ). The output subassembly (C) contains transmission components for a front-transverse drive ( 41, 42, 43 ), for a front-longitudinal or rear-longitudinal drive ( 39 ) or for an all wheel drive ( 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56 ).

Description:
This application claims priority from German Application Serial No. 102 53 259.1 field Nov. 15. 2002. 
   FIELD OF THE INVENTION 
   The invention concerns a motor vehicle transmission that is constructed as a back gear transmission. 
   BACKGROUND OF THE INVENTION 
   Motor vehicle transmissions of this type are described, for example, in DE 198 21 164 A1, DE 198 60 251 A1 and DE 199 23 185 A1. Moreover, it is known that automatic transmissions and manual transmissions differ sharply in their internal construction so that in each case different transmission components are necessary to be able to manufacture different transmissions of this type. In addition to this, automatic and manual transmissions are to be adapted construction-wise to the respective type of power train as well as to construction space conditions in concrete motor vehicle types. 
   These marginal conditions lead to the necessity of producing a type of transmission, for example for a motor vehicle having rear drive and having a motor and transmission that are arranged parallel to the direction of drive, independent of the differentiation between automatic and manual transmission, that is different from a transmission for a motor vehicle having an identical motor-transmission arrangement and front drive. Finally, as a rule, different all-wheel power train variants must also be considered so that the variety of different transmission types and transmission variants is very large. 
   The large number described leads to a desire to use the transmission components that are used in the various transmission types and transmission variants in a manner that overlaps the transmission types and transmission variants. These endeavors have nonetheless up until now faced narrow restrictions. 
   The objective of the invention therefore consists in standardizing the large number of different types and variants of automatic and manual transmissions to a large extent, so as to be able to save on development, manufacturing, repair and storage costs. 
   SUMMARY OF THE INVENTION 
   Consequently, in accordance with the invention, a motor vehicle transmission is constructed as an assembly of prefabricated machine parts which is outfitted with a start-up subassembly A, a core transmission B, and an output subassembly C, which are respectively drive-engineering connected with one another and are arranged jointly in a transmission housing. The start-up group can moreover contain a clutch, a double clutch or a torque converter, while the core transmission is constructed as a back gear transmission that has available at least one transmission input shaft, a back gear shaft, and at least one transmission output which is not oriented coaxially toward the at least one transmission input shaft. With respect to the output subassembly, it is provided that this contains transmission components for a front transverse drive, for a front longitudinal drive, for a rear longitudinal drive or for an all-wheel drive. 
   In a preferred refinement of the invention, the start-up subassembly, the core transmission, and the output subassembly include transmission components and/or individual transmission components assembled modular-like individually according to transmission type and/or power train. Moreover, subassembly groups A N , B N , C N  can belong to the start-up subassembly A, the core transmission B and the output subassembly C, which can be freely combined with one another so that, for example, the following subassembly combinations result: A 1 +B 3 +C 2 , A 7 +B 5 +C 1  or A 1 +B 5 +C 1 . 
   Manual transmissions, automatic gear boxes, automatic transmissions or manually shiftable or automated shiftable double clutch transmissions with two transmission input shafts can belong, for example, to the variants B N  of the core transmission B. 
   Preferably the core transmission is constructed as a back gear transmission, in which ratchet wheels are fastened fixed against rotation on least one of the transmission shafts, and speed gears are pivoted on at least another transmission shaft, whereby the fixed gears and the idler gears, respectively stand in meshing, forming a gear wheel pair with one another. Moreover, it is provided with such reduction gearing transmissions that the idler gears can be connected by means of coupling devices to the transmission shaft allocated to them, and the coupling devices are arranged such that they are torsion-resistant and can be axially displaced. 
   It is provided in an especially advantageous refinement of the invention that the speed gear wheels for the various gear steps are arranged in the transmission such that, beginning from the input side of the transmission, first the fourth gear and then the sixth gear, the second gear, the reverse gear, the seventh gear, the fifth gear, the third gear and the first gear lie one behind the other in the transmission. 
   It is of particular advantage if the speed gear wheels of the fourth gear, the sixth gear, the second gear and the reverse gear are arranged one behind the other on the first transmission input shaft beginning from the transmission input side, while on the second transmission input shaft, the speed gear wheels of the seventh gear, the fifth gear, the third gear and the first gear are positioned one behind the other. 
   The first or the second transmission input shaft is constructed as a hollow shaft in which the respectively other transmission input shaft is mounted, in order to be able to construct the transmission very compactly. Moreover, the two transmission input shafts are connected on the input side, respectively with the clutch components of a double clutch allocated to them. With the other representations, one proceeds from the assumption that the first transmission input shaft is constructed as a hollow shaft in which the second transmission input shaft is mounted. 
   A further aspect in the construction of the core transmission concerns the arrangement of the loose and fixed gears on the two transmission input shafts. Hence it is preferably provided that two idler gears and two fixed gears are arranged on the first transmission input shaft, while the second transmission input shaft bears exclusively fixed gears. 
   In addition, the gear wheels are constructed on the transmission output shaft such that, viewed from the input side of the transmission, two fixed gears are arranged before six idler gears. 
   A coupling device is arranged on the transmission input shaft and the transmission output shaft between two idler gears each, in order to actuate a concrete gear step; said coupling devices are preferably constructed as clutch sleeves. These coupling devices can be slid axially on the respective transmission shaft by means of adjusting devices, wherein these adjusting devices can be actuated by hand via a manual transmission or by automated or automatic transmissions using hydraulic or pneumatic adjusting apparatus such as piston-cylinder arrangements. 
   To actuate the coupling devices using a manual double clutch transmission constructed in accordance with the invention, for example the manual shifting device known from the not previously published German patent application DE 102 31 547 can be used with advantage. 
   With respect to the orientation of the transmission shafts in a transmission housing of a motor vehicle transmission constructed in accordance with the invention, it is preferably provided that the transmission output shaft is arranged beneath the two transmission input shafts with respect to its installation site inside a motor vehicle. Nonetheless, installation variants are also conceivable for which it is advantageous if the transmission output shaft is arranged above or beside a transmission input shaft. 
   In an all-wheel drive version of a transmission constructed in accordance with the invention, the transmission output shaft can be connected to a drive shaft (Cardan shaft) that leads to a rear axle drive, so that a part of the drive output generated by the drive motor can be transmitted to the rear wheels, while the other part is conducted to the front wheels. 
   In order now to construct a motor vehicle transmission in longitudinal construction for a pure motor vehicle front wheel drive using the core transmission, the transmission output shaft is preferably connected to an auxiliary shaft on its end that is directed toward the transmission input, with said auxiliary shaft bearing a fixed gear that stands in mesh with a spur bevel wheel of a front axle differential transmission. 
   In another refinement of the invention, the core transmission is outfitted with transmission components for an all-wheel drive for front-longitudinal configurations, in which the drive output for the front axle and the rear axle of the motor vehicle are issued from the side of the transmission that lies on the opposite end of the transmission input. 
   For this purpose, a fixed gear is arranged at the end of the transmission output shaft that points away from the transmission input, or on a first auxiliary shaft that is fastened there, wherein said fixed gear meshes with a fixed gear on a second auxiliary shaft that is constructed as a hollow shaft or has a hollow shaft segment, and is coaxially installed on the second transmission input shaft of the core transmission. 
   Moreover, it is provided that this second auxiliary shaft is connectable with a drive shaft that leads to a rear axle drive, and that the fixed gear stands in mesh with a further fixed gear on the transmission output shaft or the first auxiliary shaft, which fixed gear is arranged on a side shaft leading to a front axle differential transmission. 
   This side shaft can moreover be oriented obliquely or axially parallel toward the transmission output shaft and/or the transmission input shafts, wherein when the side shaft is obliquely oriented in the input region of the transmission, [it] can be accommodated for the front axle differential transmission, and the side shaft bears a fixed gear that meshes with a spur bevel gear of the front axle differential transmission. 
   In one variant of the previously described all-wheel drive, the second auxiliary shaft on the second transmission input shaft can also be dispensed with, so that an all-wheel power train with axle offset for front and rear longitudinal configurations can be constructed. For this, a fixed gear is arranged on the transmission output shaft or on an auxiliary shaft fastened to it, which fixed gear stands in mesh with a gear wheel, which, with the front axle drive module described, is fastened on a side shaft positioned obliquely or axially parallel leading to a front axle differential transmission and to the transmission output shaft and/or the transmission input shafts, whereby a drive shaft with axle offset relative to the transmission input shafts that lead to a rear axle transmission can be fastened on the transmission output shaft or on the auxiliary shaft. 
   In another variant of the invention, the core transmission is used for the construction of an all-wheel transmission with integrated longitudinal distribution transmission for motor vehicles having front and rear longitudinal configurations. For this purpose, the transmission output shaft drives the input side of a longitudinal distributor transmission with its end that points away from the input side of the transmission, wherein the output shaft of said longitudinal distributor transmission bears a fixed gear that meshes with a fixed gear on an auxiliary shaft of the rear axle drive module that is designed as a hollow shaft or has a hollow shaft segment. This auxiliary shaft is coaxially mounted on the second transmission input shaft and is connectable with a drive shaft that leads to a rear axle transmission. 
   In addition to this, the second output of the longitudinal distributor transmission disposes of a gearing, preferably an external gearing, which meshes with a fixed gear on a side shaft of the front axle drive module, which, as was already described with the preceding variant, leads to a front axle differential transmission and is obliquely oriented or is oriented parallel to the axle toward the transmission output shaft and/or the transmission input shafts. Moreover, a fixed gear is fastened on the obliquely arranged side shaft and meshes with the spur bevel gear of the front axle differential transmission. 
   In a further variant of the invention, it can be provided that the transmission output shaft drives a longitudinal distributor transmission with its end that points away from the transmission input shaft, with the output shaft of the longitudinal distributor transmission being connectable with a drive shaft that leads to a rear axle transmission. 
   The second output of this longitudinal distributor transmission moreover has available an external gearing, which meshes with a fixed gear on a side shaft of the front axle drive module described, which leads to a front axle differential transmission and is oriented obliquely or axially parallel toward the transmission output shaft and/or the transmission input shafts. 
   The longitudinal distributor transmissions mentioned are preferably constructed as Torsen differential transmissions. 
   Instead of a longitudinal distributor transmission, a core transmission of the invention can also be outfitted with a longitudinal distributor clutch in order then to create a comparatively economical motor vehicle transmission for all-wheel drive with drive units arranged up front longitudinally in the vehicle. 
   For this, it is provided that a first auxiliary shaft is fastened coaxially on the end of the transmission output shaft that faces away from the transmission input side of the core transmission, which auxiliary shaft is connected with the input side of a longitudinal distributor clutch. In addition, a fixed gear is arranged on this first auxiliary shaft, which meshes with a further fixed gear that is arranged torsion-resistant on a second auxiliary shaft. 
   This second auxiliary shaft is a component of the already described rear axle drive module and is preferably constructed as a hollow shaft or at least has a hollow shaft segment with which this is mounted on the second transmission input shaft. The second auxiliary shaft can moreover be connected with a drive shaft that leads to a rear axle transmission, thus to a Cardan shaft, on its side that points away from the input side of the core transmission. 
   In order to forward a drive torque to the front wheels of the motor vehicle, the output side of the longitudinal distributor clutch is connected to a gear wheel that is arranged on the first auxiliary shaft such that it can rotate, or bears an external gearing that meshes with a fixed gear on a side shaft of the already described front axle drive module. This side shaft leads to a front axle differential transmission and is oriented obliquely or axially parallel to the first transmission output shaft and/or the transmission input shafts. With an oblique arrangement of the side shaft, the front axle differential transmission can be incorporated into the overall transmission. 
   To realize an all-wheel variant with an integral longitudinal distributor clutch and an axle offset between the two transmission input shafts and the drive shaft that leads to the rear wheels, it can be provided that the transmission output shaft is coaxially connected to an auxiliary shaft, which stands in connection with the input side of a longitudinal distributor clutch. 
   The first output of this longitudinal distributor clutch is connectable with the drive shaft that leads to a rear axle transmission, while its second output is drive-engineering coupled with a gear wheel pivoted on this auxiliary shaft, or has an external gearing that stands in mesh with a fixed gear on a side shaft of the front axle drive module. This side shaft leads to a front axle differential transmission of the all-wheel power train, and is oriented obliquely or axially parallel to the first transmission output shaft and/or the transmission input shafts. 
   In order to construct an all-wheel power train with a motor vehicle transmission in which both the front wheel drive and the rear wheel drive of the motor vehicle can be decoupled from the core transmission when necessary, a first auxiliary shaft is fastened coaxially on the core transmission on the side of the transmission output shaft that points away from the input side, the other end of which is connected with the input side of a first longitudinal distributor clutch. 
   The output side of this first longitudinal distributor clutch has an external gearing or stands in connection with a gear wheel that is pivoted on the transmission output shaft and meshes with a fixed gear on a side shaft of the already described front axle drive module. As with the other variants described, this side shaft leads to a front axle differential transmission, and is oriented obliquely or axially parallel to the transmission output shaft and/or the transmission input shafts. 
   Moreover a second gear wheel is fastened on this first auxiliary shaft and meshes with a fixed gear that is arranged on a second auxiliary shaft. This second auxiliary shaft is constructed as a hollow shaft or has at least one hollow shaft segment with which this second auxiliary shaft is coaxially mounted on the second transmission input shaft. Finally, the end of the second auxiliary shaft that points away from the transmission input side stands in connection with the input side of a second longitudinal distributor clutch, whose output side can be drive-engineering coupled with a drive shaft that leads to a rear axle transmission. 
   In a variant of the previously described motor vehicle transmission having two longitudinal distributor clutches, it can be provided that the power train has an axle offset between the two transmission input shafts and the drive shaft that leads to the rear axle. 
   For this, the transmission output shaft is coaxially connected at its end that points away from the transmission input side to a first auxiliary shaft, the other end of which stands in connection with the input side of a first longitudinal distributor clutch. The output side of this first longitudinal distributor clutch is consequently connectable with a drive shaft that leads to a rear axle transmission. 
   In addition to this, a fixed gear is fastened to the first auxiliary shaft and stands in mesh with a fixed gear on a second auxiliary shaft. This second auxiliary shaft for its part is connected to the input side of a second longitudinal distributor clutch. The output side of this second longitudinal distributor clutch now stands in connection with a side shaft that leads to a front axle differential transmission and is oriented obliquely or axially parallel to the first transmission output shaft and/or to the two transmission input shafts. 
   In another variant of the invention, the core transmission is outfitted with two longitudinal distributor clutches arranged axially one behind the other, and is provided with an axle offset, which is better suited for other construction space conditions in other motor vehicle types than the previously sketched power train structures. Accordingly, the core transmission is coaxially connected to an auxiliary shaft on the end of the transmission output shaft that points away from the transmission input, on whose end that points away from the transmission output shaft the input sides of the first and second longitudinal distributor clutch are fastened. 
   The output side of the second longitudinal distributor clutch can be connected to a drive shaft that leads to a rear axle transmission, while the output side of the first longitudinal distributor clutch is connected to a gear wheel that is mounted on the auxiliary shaft or bears an external gearing that stands in mesh with a fixed gear on a side shaft of the already described front axle drive module that leads to a front axle differential transmission. This side shaft can be oriented obliquely or axially parallel to the first transmission output shaft and/or to the two transmission input shafts. 
   Moreover, a motor vehicle transmission without axle offset between the transmission input shafts and the drive shaft leading to the rear axle be constructed by a first auxiliary shaft being coaxially fastened on the side of the transmission output shaft that points away from the input side of the core transmission, with said auxiliary shaft standing in propulsive connection with the input side of a first longitudinal distributor clutch. 
   The output side of this first longitudinal distributor clutch has an external gearing or is connected with a gear wheel that is mounted on the transmission output shaft and meshes with a fixed gear that is fastened on a side shaft of the already described front axle drive module that leads to a front axle differential transmission. This side shaft can be arranged obliquely or axially parallel to the transmission output shaft and/or the transmission input shafts. 
   In addition to this, a fixed gear is arranged on the first auxiliary shaft and meshes with an external gearing on the input side of a second longitudinal distributor clutch or stands in mesh with a gear wheel that is connected to the input side of the second longitudinal distributor clutch. This input side of the second longitudinal distributor clutch is moreover connected to a second auxiliary shaft that is constructed as a hollow shaft or has a hollow shaft segment and is mounted on the second transmission input shaft. Finally, the output side of the second longitudinal distributor clutch can be connected to a drive shaft leading to a rear axle transmission. 
   In another refinement of the invention, to furnish an all-wheel motor vehicle transmission having two integral longitudinal distributor clutches and an integral front axle distributor transmission, it is provided that the end of the transmission output shaft that points toward the input side of the transmission is connected to the input side of a first longitudinal distributor clutch whose output side stands in propulsive connection with a first auxiliary shaft that leads to a front axle differential transmission. 
   The first auxiliary shaft either leads to a separate front axle differential transmission or bears a fixed gear that meshes with the spur bevel gear of the front axle differential transmission. The end of the transmission output shaft that points away from the input side of the transmission is, in contrast, connected to the input side of a second longitudinal distributor clutch whose output side stands in propulsive connection with a second auxiliary shaft. 
   A gear wheel is fastened on this second auxiliary shaft that meshes with a further gear wheel, which is wedged on a third auxiliary shaft. This third auxiliary shaft is constructed as a hollow shaft or has a hollow shaft segment with which this third auxiliary shaft is coaxially mounted on the second transmission input shaft. Finally this third auxiliary shaft can be connected to a drive shaft that leads to a rear axle transmission. 
   For a motor vehicle transmission having two longitudinal distributor clutches and an axle offset between the transmission input side and the drive shaft leading to the rear axle, it can be provided that the end of the transmission output shaft that points toward the input side of the transmission is connected to the input side of a first longitudinal distributor clutch. 
   The output side of this first longitudinal distributor clutch then stands in propulsive connection with a first auxiliary shaft, which leads to a front axle differential transmission and bears a fixed gear that meshes with the spur bevel gear of the front axle differential transmission. Furthermore, it is provided that the end of the transmission output shaft that points away from the input side of the transmission is connected to the input side of a second longitudinal distributor clutch whose output side can be connected to a drive shaft that leads to a rear axle transmission. 
   Finally, an all-wheel drive configuration with the core transmission, in which the end of the transmission output shaft that points toward the input side of the transmission is connected to the input side of a first longitudinal distributor clutch, is possible. The output side of this first longitudinal distributor clutch is then connected to a first auxiliary shaft that leads to a separate front axle differential transmission. 
   The end of the transmission output shaft that points away from the input side of the transmission is moreover connected to the input side of a second longitudinal distributor clutch, whose output side can be drive engineering connected to a drive shaft that leads to a rear axle transmission. 
   Furthermore, for some power train and transmission variants having longitudinal distributor clutches, it can be provided that a front axle differential transmission is incorporated in the core transmission in each case. 
   Moreover, a reverse speed shaft preferably belongs to the core transmission, on which shaft a reverse speed gearwheel is fastened, which stands in mesh with the reverse speed fixed gear and the reverse speed idler gear on the transmission input shaft or on the transmission output shaft, for the purpose of generating a reversal of the direction of rotation and forwarding a drive torque. 
   Finally, it can be advantageous for reasons of costs and construction space if the transmission components to be connected to the core transmission are not arranged on separate auxiliary shafts but rather on or near the main shafts (transmission input shaft and transmission output shaft) of the core transmission. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  illustrates a schematic representation of a double clutch core transmission for the front longitudinal incorporation in a motor vehicle with rear drive; 
       FIG. 2  illustrates a representation as in  FIG. 1 , but with front longitudinal drive arrangement; 
       FIG. 3  illustrates a representation as in  FIG. 1 , but as an all-wheel transmission for a front and rear longitudinal power train with integral front axle differential transmission; 
       FIG. 4  illustrates a representation as in  FIG. 3 , but without front axle differential transmission; 
       FIG. 5  illustrates an all-wheel variant with axle offset for a front and rear longitudinal power train with front axle differential transmission; 
       FIG. 6  illustrates a representation as in  FIG. 5 , but without front axle differential transmission; 
       FIG. 7  illustrates an all-wheel variant with integral longitudinal distributor transmission for a front and rear longitudinal power train with front axle differential transmission; 
       FIG. 8  illustrates a representation as in  FIG. 7 , but without front axle differential transmission; 
       FIG. 9  illustrates an all-wheel variant with axle offset and an integral longitudinal distributor transmission for a front and rear longitudinal power train with front axle differential transmission; 
       FIG. 10  illustrates a representation as in  FIG. 9 , but without front axle differential transmission; 
       FIG. 11  illustrates an all-wheel variant with an integral longitudinal distributor clutch for a front and rear longitudinal power train with front axle differential transmission; 
       FIG. 12  illustrates a representation as in  FIG. 11 , but without front axle differential transmission; 
       FIG. 13  illustrates an all-wheel variant with axle offset and an integral longitudinal distributor clutch for a front and longitudinal power train with front axle differential transmission; 
       FIG. 14  illustrates an all-wheel variant with an integral longitudinal distributor clutch and axle offset; 
       FIG. 15  illustrates an all-wheel variant with two integral longitudinal distributor clutches; 
       FIG. 16  illustrates an all-wheel variant with two integral longitudinal distributor clutches and axle offset; 
       FIG. 17  illustrates an all-wheel variant with two integral longitudinal distributor clutches and integral front axle differential transmission; 
       FIG. 18  illustrates an all-wheel variant with two integral longitudinal distributor clutches and axle offset; 
       FIG. 19  illustrates an all-wheel variant with two integral longitudinal distributor clutches, axle offset and integral front axle differential transmission; 
       FIG. 20  illustrates an all-wheel variant with two integral longitudinal distributor clutches, integral front axle differential transmission in a slender variant; 
       FIG. 21  illustrates an all-wheel variant with two integral longitudinal distributor clutches in a slender variant without front axle differential transmission; 
       FIG. 22  illustrates an all-wheel variant with two integral longitudinal distributor clutches, axle offset and integral front axle differential transmission in a slender variant; and 
       FIG. 23  illustrates an all-wheel variant with two integral longitudinal distributor clutches, axle offset in a slender variant without front axle differential transmission. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As  FIG. 1  shows, a transmission according to the invention basically consists of three main components to which a start-up subassembly A, a core transmission B and an output subassembly C belong. With a power train  1  represented, by way of example in this Figure, a drive motor  2  and the transmission for driving the rear wheels are oriented longitudinally in the direction of travel of the motor vehicle. The motor  2  is connected via its crankshaft  3 , to the input side of the start-up subassembly A, which in this embodiment has a torsional vibration damper  4 . The output side of this torsional vibration damper  4  then stands in drive-engineering connection with the input side of a start-up and/or shifting clutch that is constructed as a double clutch  5 . 
   The two output sides of the double clutch  5  are connected via a first transmission input shaft  6  and a second transmission input shaft  7  to the double clutch core transmission B, wherein the first transmission input shaft  6  is constructed as a hollow shaft which bears the second transmission input shaft  7  coaxially. Moreover, the two transmission input shafts  6 ,  7  are installed in bearings housing that is not represented here. 
   In this exemplary embodiment, a total of four speed gear wheels are arranged on the first transmission input shaft  6  in this embodiment, of which two gear wheels  11 ,  12  near the transmission input are constructed as idler gears, which are mounted axially, unmovable or rotatably, on this first transmission input shaft  6 . Two other gear wheels  13 ,  14  are constructed as fixed gears and are connected torsion resistant to the first transmission input shaft  6 . 
   The two idler gears  11 ,  12  can be connected torsion-resistant, alternatively to one another, to the first transmission input shaft  6 , via a sliding sleeve  31 , that is arranged torsion-resistant, but axially displaceable on this first transmission input shaft  6 . For actuating the sliding sleeve  31 , an actuation device  35  is present which can be manually displaced by the driver of the motor vehicle using a manual shift version of the transmission, via a rod, that is not represented here, while with an automated or automatic motor vehicle transmission of identical construction, this actuation of the adjusting device preferably is accomplished via piston-cylinders that also are not represented here. 
   The speed gear wheels on the second transmission input shaft  7  are exclusively constructed as fixed gears  15 ,  16 ,  17 ,  18  and fastened there. 
   In addition to the two transmission input shafts  6 ,  7 , a transmission output shaft  19  as a further main transmission shaft is arranged parallel to the two input shafts  6 ,  7  in the transmission housing and installed by means of bearings  20 ,  21 ,  22 . 
   The speed gear wheels arranged on the transmission output shaft  19  of this core transmission are in this case constructed such that in each case a fixed gear on the transmission output shaft  19  stands in mesh with an idler gear on one of the two transmission input shafts  6 ,  7 , or an idler gear on the transmission output shaft  19  meshes with a fixed gear on one of the transmission input shafts  6 ,  7 . 
   Thus, first two fixed gears  23 ,  24  are fastened on the transmission output shaft  19  near the transmission input, followed by a total of six idler gears  25 ,  26 ,  27 ,  28 ,  29 ,  30 . Between every two idler gears  25 ,  26 ;  27 ,  28 ;  29 ,  30  a sliding sleeve  32 ,  33 ,  34  is arranged, torsion resistant and axially displaceable, on the transmission output shaft  19 , with which the idler gears  25 ,  26 ;  27 ,  28 ;  29 ,  30  can be connected, alternatively to one another, torsion-resistant to the transmission input shaft  19 . 
   Actuation devices  36 ,  37 ,  38  are also present here for actuating the sliding sleeves  32 ,  33 ,  34 , which devices can be actuated manually by the driver in a manual shifting version of the transmission, while with an automated or automatic motor vehicle transmission of identical construction, the actuation of the above-mentioned adjusting devices preferably is accomplished by means of piston-cylinder arrangements not represented here. 
   As  FIG. 1  shows, the speed gear wheels are lined up on the two transmission input shafts  6 ,  7  and the transmission output shaft  19  such that, proceeding from the double clutch  5  on the transmission input, the ratchet wheel pairs of the fourth gear  4 ′, the sixth gears  6 ′, the second gear  2 ′, the reverse gear R, the seventh gear  7 ′ the fifth gear  5 ′, the third gear  3 ′ and the first gear  1 ′ are arranged one after the other. 
   Moreover, it can be inferred from  FIG. 1  that the ratchet wheels  14 ,  26  for the reverse gear R obviously do not mesh directly with one another. Rather, a further ratchet wheel is necessary for reversing the direction of rotation, which is installed together with a reverse gear shaft in the transmission housing in an inherently known manner, and is 
     FIG. 1  further shows that the output of the core transmission B is not arranged coaxially in relation to the two transmission input shafts  6 ,  7 . Hence the components of an output subassembly C can be fastened on the side of the transmission output shaft  19  that points away from the transmission input side, to which components a drive shaft  39 , constructed in this embodiment of the invention as a Cardan shaft, belongs. With the drive shaft  39 , a drive torque is forwarded from the transmission arranged forward in the motor vehicle to a rear axle differential transmission. 
   As  FIG. 2  shows, the double clutch core transmission A represented in  FIG. 1  can be simply constructed for a motor vehicle with front drive in that an output subassembly C is fastened with an auxiliary shaft  41 , on the end of the transmission output shaft  19  that points toward the transmission input side, whose fixed gear  42  meshes with a spur bevel gear  43  of a front axle differential transmission. This front axle differential transmission is moreover preferably incorporated into the transmission housing in the region of the double clutch. 
   In addition to the outfitting of the double clutch core transmission with transmission components for simple front or rear drive variants, the construction of the core transmission in accordance with the invention is chiefly usable with great advantage for all-wheel power trains. 
   As  FIG. 3  shows, with such an all-wheel power train on the motor vehicle transmission  54 , the transmission output shaft  19  is connected to an output subassembly C at its end that points away from the transmission input, in which subassembly, a gear wheel  45 , is fastened on a first auxiliary shaft  44 . The gear wheel  45  drives a fixed gear  46  of the rear axle drive module, which is fastened on a second auxiliary shaft  47 . The second auxiliary shaft  47  is constructed as a hollow shaft or has at least a hollow shaft segment  48  that is represented here, with which the auxiliary shaft  47  is pivoted on the free end of the second transmission output shaft  7 . 
   In addition, the second auxiliary shaft  47  can be connected to a drive shaft  49 , with which a drive torque is forwarded to a rear axle differential transmission (not shown). 
   To supply the front wheels with a drive output, the geared wheel  44  further meshes with a fixed gear  50  of a front axle drive module that belongs to the output subassembly C, which gear is fastened on a side shaft  51  that is set obliquely and mounted in bearings  55 ,  56 . The side shaft  51  bears at its other end a fixed gear  52 , which stands in mesh with a spur bevel gear  53  of a front axle differential transmission that is incorporated into the overall transmission. 
   In a modification of the motor vehicle transmission  54  in accordance with  FIG. 3 , the latter can also be outfitted with a front axle drive module, in which a side shaft  58  is arranged not obliquely, but rather axially parallel in relation to the transmission output shaft  19  and the two transmission input shafts  6 ,  7  ( FIG. 4 ). The side shaft  58  leads to a separate front axle differential transmission, which is not, as with the transmission in accordance with  FIG. 3 , arranged in the immediate vicinity of the double clutch  5 . 
   To the extent that it is desirable to position the drive shaft that leads to the rear axle differential transmission as deeply as possible, in order to avoid, for example, having to provide a Cardan tunnel in the motor vehicle body, the core transmission B can also be constructed as an all-wheel motor vehicle transmission  59  with an axle offset between the transmission input shafts  6 ,  7  and the Cardan shaft. As  FIG. 5  shows, for this purpose an auxiliary shaft  60  of an output subassembly C is fastened coaxially on the transmission output shaft  19  of the core transmission A, which auxiliary shaft bears a fixed gear  61  that meshes with the fixed gear  50  known from the transmissions in accordance with  FIG. 3  on the obliquely positioned side shaft  51  of the front axle drive module. The obliquely positioned side shaft  51  toward a front wheel differential transmission preferably incorporated in the transmission housing. 
   In addition to this, the auxiliary shaft  60  of the output subassembly C can be connected to a drive shaft  62  that leads to a rear axle differential transmission, so that an all-wheel motor vehicle transmission can be manufactured without great construction expense, based upon the core motor vehicle transmission. 
     FIG. 6  now shows that the transmission in accordance with  FIG. 5  can also be constructed as an all-wheel drive with axle offset for front and rear longitudinal drive, in which the side shaft  58  of the output subassembly C is arranged axially parallel to the transmission output shaft  19  and to the two transmission input shafts  6 ,  7 . The side shaft  58  leads to a front axle differential transmission, while the rear axle is driven via the drive shaft  62  by the auxiliary shaft  60  that is connected to the transmission output shaft  19 . 
   However, the core transmission B of the invention can also be very advantageously combined with an output subassembly C, into which a longitudinal distributor transmission, for example a Torsen differential transmission, is incorporated, without changes having to be undertaken on the core transmission B. 
   Hence  FIG. 7  shows a motor vehicle transmission  64  in which the transmission output shaft  19  of the core transmission B is drive-engineering connected to the input side of a longitudinal distributor transmission  65 , which belongs to the output subassembly C. Moreover, the one output side of the longitudinal distributor transmission  65  stands in connection with a first auxiliary shaft  66  on which the gear wheel  45 , known from the transmission in accordance with  FIG. 3 , is fastened. 
   The gear wheel  45  meshes with the gear wheel  46  of the already described rear axle drive module, which is fastened on the second auxiliary shaft  47 , just as with the transmission in accordance with  FIG. 3 , wherein the auxiliary shaft  47 , in this case, also has a hollow shaft segment  48 , which is pivoted on the free end of the second transmission input shaft  7 . In addition, the free end of the second auxiliary shaft  47  can be connected to the drive shaft  49  that leads to the rear axle transmission. 
   Just as with the motor vehicle transmission  64  with its longitudinal distributor transmission  65 , the transmission components  46 ,  47 ,  48 ,  49 , combined in a modular fashion, could be used for the rear axle output, the transmission components known from the transmission in accordance with  FIG. 3  can also be used for the front axle drive with the transmission  64 . 
   Hence the second output side of the longitudinal distributor transmission  65  is outfitted with an external gearing that meshes with the fixed gear  50  on the obliquely positioned side shaft  51  of the front axle drive module. The side module  51  bears, on the output side, the fixed gear  52 , which stands in mesh with the spur bevel gear  53  of the front axle differential transmission that is incorporated into the transmission housing. 
   As  FIG. 8  shows, the motor vehicle transmission  64  in accordance with  FIG. 7  can also be constructed with a front axle drive module having a side shaft  58 , which is oriented parallel to the transmission output shaft  19  and the two transmission input shafts  6 ,  7 . 
     FIG. 9  and  FIG. 10  show further variants of the all-wheel motor vehicle transmission  64  in accordance with  FIG. 7 . Motor vehicle transmissions  69 ,  71  have an axle offset between the two transmission input shafts  6 ,  7  and the transmission output that points toward the rear axle. 
   Thus a drive shaft  70  that leads to the rear axle can be fastened to the auxiliary shaft  66  that is connected to the first output of the longitudinal distributor transmission  65 , while a second output side (external gearing  67 ) of the longitudinal distributor transmission  65  is drive-engineering connected to the front axle drive module of the transmission assembly. 
   The front axle drive module in the output subassembly C is comprised of a fixed gear  50 , which is fastened on the obliquely positioned side shaft  51  or on the side shaft  58  that is axially parallel to the transmission output shaft  19  and to the two transmission input shafts  6 ,  7  and that leads to the front axle differential transmission. 
   Instead of the longitudinal distributor transmission  65 , the output assembly C can also be outfitted with a longitudinal distributor clutch with which a comparatively economical distribution of the drive torque to the front and rear axles is possible. 
   As  FIG. 11  shows, the end of the transmission output shaft  19  that points away from the input side of the core transmission B is connected for this purpose to a first auxiliary shaft  73  of the output subassembly C on which a gear wheel  74  is fastened. The gear wheel  74  drives the already described rear axle drive module, which is comprised of the gear wheel  46  that meshes with the gear wheel  74  and is fastened on the second auxiliary shaft  47 , which is constructed as a hollow shaft or has at least one hollow shaft segment  48 . The second auxiliary shaft  47 , moreover, is pivoted on the free end of the second transmission input shaft  7  and can be connected to the drive shaft  49  that leads to the rear axle transmission. 
   Above and beyond this, the first auxiliary shaft  73  of the output subassembly C is connected to the input side of the longitudinal distributor clutch  75 , whose output side either bears an external gearing or is connected to a gear wheel  76  that is pivoted on the first auxiliary shaft  73 . The gear wheel  76  or this external gearing meshes with the gear wheel  50  of the front axle drive module, which, in a transmission  72  in accordance with  FIG. 11 , is comprised of the obliquely positioned side shaft  51  and the fixed gear  52  fastened thereupon, wherein the latter meshes with the spur bevel gear  53  of a front axle differential transmission that is incorporated into the transmission housing. 
   A motor vehicle transmission  77  in accordance with  FIG. 12  differs from the transmission in accordance with  FIG. 11  in that the front axle drive module here is comprised of the side shaft  58 , which is arranged axially parallel to the transmission output shaft  19  and toward the two transmission input shafts  6 ,  7 , and thus leads to the front axle differential transmission. 
   To realize a motor vehicle transmission  78  with a longitudinal distributor clutch  83  and an axle offset between the two transmission input shafts  6 ,  7  and the output to the rear axle, the transmission of the invention is constructed such that the transmission output shaft  19  is drive-engineering connected to the auxiliary shaft  73  of an output subassembly C, which stands in drive-engineering connection with the input side of a longitudinal distributor clutch  75  and with the drive shaft  70  that leads to the rear axle transmission. 
   The output to its front axle takes place just as with the transmission in accordance with  FIG. 11 , via the external gearing of the output side of the longitudinal distributor transmission  75  or via the gear wheel  76  that is connected to this output side and meshes with the gear wheel  50  of the already described front axle drive module. 
   With the transmission in accordance with  FIG. 13 , this module comprises the obliquely positioned side shaft  51  with the fixed gear  52  and the spur bevel gear  53  of the front axle differential transmission, while with the variant of a motor vehicle transmission  79  in accordance with  FIG. 14 , the side shaft  58  that is axially parallel in relation to the transmission output shaft  19  and to the two transmission input shafts  6 ,  7  is incorporated. 
   To the extent that a motor vehicle transmission  80  is required in which both the power train to the rear wheels and the power train to the front wheels should be completely separated from the transmission when required, the core transmission B can be connected with two separate longitudinal distributor clutches  75 ,  81  of an output subassembly C, as represented in  FIG. 15 . 
   With the transmission  80 , the transmission output shaft  19  is drive-engineering connected to the first auxiliary shaft  73  as with the transmission  79  in accordance with  FIG. 14 , which also drives the input side of the first longitudinal distributor clutch  75 . The first longitudinal distributor clutch  75 , as already described, has an external gearing or is connected to the gear wheel  76  that is pivoted on the first auxiliary shaft  73 . 
   If this first longitudinal distributor clutch  75  is closed, the gear wheel  76  drives the gear wheel  50  of the side shaft  58 , which is arranged axially parallel to the transmission output shaft  19  and to the two transmission input shafts  6 ,  7  in the transmission housing, and leads to a front axle differential transmission. 
   An all-wheel motor vehicle transmission  82  with two longitudinal distributor clutches  75 ,  83  and an axle offset between the transmission input side and the drive shaft  70  that drives to the rear axle can be attained in that the double clutch core transmission B in accordance with  FIG. 16  is drive-engineering connected to the auxiliary shaft  73  of output subassembly C on its transmission output shaft  19 , which drives the input side of the first longitudinal distributor clutch  75 . The output side of this first longitudinal distributor clutch  75  can be connected to the drive shaft  70 , which has already been described several times, to drive the rear axle transmission (not shown). 
   In addition, here again the auxiliary shaft  73  is connected to the gear wheel  74 , which meshes with the gear wheel  50 , which is fastened on a second auxiliary shaft  84 . The second auxiliary shaft  84  is moreover drive-engineering connected with the input side of a second longitudinal distributor clutch  83 , so that when the second longitudinal clutch  83  is closed, the side shaft  58  that leads to the front axle differential transmission is driven. In the embodiment of the invention shown in  FIG. 16 , the side shaft  58  is arranged axially parallel to the transmission output shaft  19  and to the two transmission input shafts  6 ,  7  in the transmission housing. 
   As  FIG. 17  shows, an all-wheel motor vehicle transmission  85  for longitudinal incorporation into the motor vehicle can also be assembled with the modular construction of the invention using the core transmission B, in which two longitudinal distributor clutches arranged, one behind the other, axially are present in the output subassembly C. Accordingly, the transmission output shaft  19  is connected to the input side of a first and a second longitudinal distributor clutch  75 ,  81 , which are arranged one behind the other axially. 
   The first longitudinal distributor clutch  75 , as with the motor vehicle transmission in accordance with  FIG. 13 , has an external gearing or a gear wheel  76  that is connected to the input side of the first longitudinal distributor clutch  75  and that meshes with the fixed gear  50  on the obliquely positioned side shaft  51  of the front axle drive module. Moreover, this side shaft  51  bears the fixed gear  52  on its end that points toward the front, which gear meshes with the spur bevel gear  53  of the front axle differential transmission that is incorporated into the transmission housing. 
   Furthermore, the output side of the second longitudinal distributor clutch  81  is connected to the drive shaft  70  that leads to the rear axle differential transmission. 
     FIG. 18  shows a transmission variant  86  of the transmission in accordance with  FIG. 17  in which, in the output subassembly C, the side shaft  58  that is axially parallel to the transmission output shaft  19 , instead of the obliquely positioned side shaft, is arranged in the transmission housing which, in the front axle drive module described, leads to a separate differential transmission for the front axle of the motor vehicle. 
   As can be gathered from  FIG. 19 , the all-wheel motor vehicle transmission  86 , having two longitudinal distributor clutches and an integral front axle differential transmission, can also be constructed using the core transmission B, wherein the side shaft  51  that is incorporated into the output subassembly and leads to the front axle differential transmission is relatively short in comparison with the side shaft  58  of the similar transmission variant  80  in accordance with  FIG. 15 . 
   In a motor vehicle transmission  88 , the transmission output shaft  19  is connected to the first intermediate shaft  73 , which drives the input side of the first longitudinal distributor clutch  75  and moreover bears a fixed gear  90 . The fixed gear  90  meshes with an external gearing on the input side of the second longitudinal distributor clutch  81  or with an idler gear  89 , which is connected to the input side of this second longitudinal distributor clutch  81  and is pivoted on the second auxiliary shaft  47 . 
   The second auxiliary shaft  47  belongs to the rear axle drive module, in which the auxiliary shaft  47  is constructed as a hollow shaft or has at least one hollow shaft segment  48 , and is mounted on the free end of the second transmission input shaft  7 . 
   The output side of this second longitudinal distributor transmission  81  is connected to the drive shaft  49  for rear axle transmission drive, so that the motor vehicle transmission  88  can be completely decoupled from the rear wheels that otherwise drive into the transmission  88 , for example, for cross country driving or in drive-less pushing operation phases. 
   The first longitudinal distributor clutch  75 , whose output side is, likewise, connected with an external gearing or with the gearwheel  76  that is pivoted on the first auxiliary shaft  73 , offers the same advantage. The gear wheel  76  meshes with the gear wheel  50  of the front axle drive module already described with the other transmission variants, so that this all-wheel power train can also be turned on and off, for example, as a function of cross country driving conditions. Moreover, it is also provided with this power train that the front axle differential can be accommodated in the transmission housing of the motor vehicle transmission  88  near the double clutch  5  owing to the oblique positioning of the side shaft  51 . 
   Particularly low diameter all-wheel motor vehicle transmission variants, which can be constructed using the core transmission B of the invention, can be inferred from  FIGS. 20 to 23 . Thus  FIG. 20  shows an all-wheel motor vehicle transmission  91  on whose transmission input proximate and transmission output distant ends in output subassembly C, a longitudinal distributor clutch  93 ,  96  is arranged, in each case. To provide the rear wheels with drive torque, the transmission-remote side of the transmission output shaft  19  is, therefore, connected to the input side of the first longitudinal distributor clutch  93 , whose output side stands in connection with a short auxiliary shaft  92  on which a fixed gear  94  is fastened. The fixed gear  94  meshes with a gear wheel  95 , which is arranged, fixed, on the auxiliary shaft  47  of a rear axle drive module. The auxiliary shaft  47  is constructed as a hollow shaft or has at least one hollow shaft segment  48  with which it is mounted on the free end of the second transmission input shaft  7 . Moreover, the drive shaft  49 , which leads to the rear axle transmission, can be drive-engineering connected to the auxiliary shaft  47 . 
   For driving the front wheels, the side of the transmission output shaft  19  that is near the transmission input is connected to the input side of the second longitudinal distributor clutch  96 , whose output side is fastened on a further auxiliary shaft  97 . The further auxiliary shaft  97  bears the fixed gear  52 , which stands in mesh with the spur bevel gear  53  of the front axle differential transmission. 
   As a modification of the transmission  91 , an all-wheel motor vehicle transmission  99  can also be constructed in accordance with  FIG. 21  such that, with respect to the transmission components driving the rear axle, the construction is identical to the transmission  91 , however, the front axle differential transmission is neither arranged directly nor close to the core components of the motor vehicle transmission. With this construction, a side shaft  98  in an output subassembly C proceeds from the output side of the second longitudinal distributor clutch  96  and leads to the front axle differential transmission. 
   A further variant of the all-wheel double clutch transmission in accordance with  FIG. 20  is illustrated in  FIG. 22 . While with a motor vehicle transmission  100 , the construction of the output subassembly C in the region of the front axle drive is identical to that of the transmission  91  in  FIG. 20 , the rear axle drive is arranged axially displaced in relation to the input side of the motor vehicle transmission. Therefore, in a further output subassembly C, the output side of the first longitudinal distributor clutch  93 , which is connected to the transmission output shaft  19 , is coupled with the shaft  92 , on which the drive shaft  70  that leads to the rear axle differential transmission is fastened. 
   The last transmission variant is represented in  FIG. 23  in which an all-wheel motor vehicle transmission  101 , likewise, has an axle offset between the transmission input side and the rear axle drive. For this, the transmission output shaft  19  is connected to the input side of the first longitudinal distributor clutch  93 , at the end of the shaft that points away from the transmission entry, in an output subassembly C, whose output side can be connected to the drive shaft  70  that leads to the rear axle transmission. The input side of the second longitudinal clutch  96  is fastened on the opposite side of the transmission output shaft  19 , while the output side stands in connection with a side shaft  102 , which leads to a front axle differential transmission that is not represented here. 
   REFERENCE NUMBERS 
   
       
         1  Motor vehicle transmission 
         2  Drive motor 
         3  Crankshaft 
         4  Torsional vibration damper 
         5  Double clutch 
         6  Transmission input shaft; hollow shaft 
         7  Transmission input shaft 
         8  Bearing 
         9  Bearing 
         10  Bearing 
         11  Idler gear 
         12  Idler gear 
         13  Fixed gear 
         14  Fixed gear 
         15  Fixed gear 
         16  Fixed gear 
         17  Fixed gear 
         18  Fixed gear 
         19  Transmission output shaft 
         20  Bearing 
         21  Bearing 
         22  Bearing 
         23  Fixed gear 
         24  Fixed gear 
         25  Idler gear 
         26  Idler gear 
         27  Idler gear 
         28  Idler gear 
         29  Idler gear 
         30  Idler gear 
         31  Sliding sleeve 
         32  Sliding sleeve 
         33  Sliding sleeve 
         34  Sliding sleeve 
         35  Adjusting device 
         36  Adjusting device 
         37  Adjusting device 
         38  Adjusting device 
         39  Drive shaft; Cardan shaft 
         40  Motor vehicle transmission 
         41  Auxiliary shaft 
         42  Output gear wheel 
         43  Spur bevel gear 
         44  First auxiliary shaft 
         45  Fixed gear 
         46  Fixed gear 
         47  Second auxiliary shaft 
         48  Hollow shaft segment 
         49  Drive shaft; Cardan shaft 
         50  Fixed gear 
         51  Side shaft 
         52  Fixed gear 
         53  Spur bevel gear 
         54  Motor vehicle transmission 
         55  Bearing 
         56  Bearing 
         57  Motor vehicle transmission 
         58  Side shaft 
         59  Motor vehicle transmission 
         60  Auxiliary shaft 
         61  Fixed gear 
         62  Drive shaft; Cardan shaft 
         63  Motor vehicle transmission 
         64  Motor vehicle transmission 
         65  Longitudinal distributor transmission 
         66  First auxiliary shafts 
         67  External gearing of longitudinal distributor transmission 
         68  Motor vehicle transmission 
         69  Motor vehicle transmission 
         70  Drive shaft; Cardan shaft 
         71  Motor vehicle transmission 
         72  Motor vehicle transmission 
         73  First auxiliary shaft 
         74  Fixed gear 
         75  Longitudinal distributor clutch 
         76  Gear wheel 
         77  Motor vehicle transmission 
         78  Motor vehicle transmission 
         79  Motor vehicle transmission 
         80  Motor vehicle transmission 
         81  Longitudinal distributor clutch 
         82  Motor vehicle transmission 
         83  Longitudinal distributor clutch 
         84  Auxiliary shaft 
         85  Motor vehicle transmission 
         86  Motor vehicle transmission 
         87  Auxiliary shaft 
         88  Motor vehicle transmission 
         89  Gear wheel, external gearing 
         90  Fixed gear 
         91  Motor vehicle transmission 
         92  Auxiliary shaft 
         93  Longitudinal distributor clutch 
         94  Fixed gear 
         95  Fixed gear 
         96  Longitudinal distributor clutch 
         97  Auxiliary shaft 
         98  Auxiliary shaft 
         99  Motor vehicle transmission 
         100  Motor vehicle transmission 
         101  Motor vehicle transmission 
         102  Auxiliary shaft 
       A Start-up subassembly 
       B Core transmission 
       C Output subassembly