Abstract:
A dual clutch transmission for motor vehicles has first and second input shafts, two clutches selectively coupling the input shafts the engine, two intermediate shafts arranged parallel to the transmission input shafts, gearwheel pairs configured to transmit power between the input shafts and the intermediate shafts, and output gearwheels arranged on each of the two intermediate shafts. The output gearwheels mesh with the differential wheel and are selectively coupled to the respective intermediate shaft by one of the coupling devices. An additional intermediate gearwheel set is provided, that one gearwheel of the intermediate gearwheel set is seated on the first or second intermediate shaft, that the other gearwheel of the inter-mediate wheel set is arranged on a third intermediate shaft, and that a third output gearwheel, which meshes with one of the output gearwheels of the first or second intermediate shaft, is seated on the third intermediate shaft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims foreign priority benefit under 35 U.S.C. §119(a)-(d) to DE 10 2016 202 915.0 filed Feb. 25, 2016, the disclosure of which is hereby incorporated in its entirety by reference herein. 
       TECHNICAL FIELD 
       [0002]    The invention relates to a dual clutch transmission for motor vehicles having a first input shaft and a second input shaft, two clutches, by means of which the first input shaft and the second input shaft can be selectively coupled to the engine, two intermediate shafts arranged parallel to the transmission input shafts, gearwheel pairs of fixed wheels and freely rotating wheels, of which a first gearwheel is arranged on one of the input shafts and a second gearwheel is arranged on one of the intermediate shafts, coupling devices, by means of which the freely rotating wheels can be selectively connected to the respective intermediate shaft, and an output gearwheel arranged on each of the two intermediate shafts, wherein the output gearwheels of both intermediate shafts mesh with the differential wheel and can each be alternately connected for conjoint rotation to the respective intermediate shaft by means of one of the coupling devices. 
       BACKGROUND 
       [0003]    There is an effort in the automotive industry to adapt the operating state of the engine in an optimum manner, during driving, to the current driving state of the motor vehicle in order to reduce emissions. This can be accomplished, for example, if the transmission has a large number of gears. In this case, selection is performed in such a way that the engine speed is held as low as possible, even at high driving speeds. Another aim is to keep down the masses which co-rotate under no load in order thereby to effect a further reduction in emissions. 
         [0004]    In a conventional design, a large number of gears necessarily implies a relatively large number of transmission gearwheels and therefore a relatively large overall length, although this is not desired in modern motor vehicle engineering, as well as a relatively high weight of the transmission and relatively high associated power losses. 
         [0005]    Known transmissions of the type stated at the outset (WO 2012/084250 A1; DE 10 2013 216 387 A1) are therefore already taking a step in the desired direction by providing the possibility of the power flowing both via a gearwheel stage associated with the first transmission input shaft and via a gearwheel stage associated with the second transmission input shaft. 
         [0006]    In the case of such dual clutch transmissions, the transmission input shafts are designed as an inner shaft and an outer shaft, wherein the inner shaft and the outer shaft can be driven selectively. The additionally selected gears can then be routed along an indirect path which runs via gearwheels that are arranged on the respective un-driven transmission input shaft. 
         [0007]    These known dual clutch transmissions, by means of which it is possible, in addition to the existing gearwheel pairs and the gears that result therefrom, to select further gears, require hollow shaft devices for this purpose on the intermediate shafts and, in some cases, also on the transmission input shafts, on which hollow shaft devices in each case at least two gearwheels are arranged, wherein the hollow shafts co-rotate freely on the transmission input shafts and intermediate shafts but can be connected thereto for conjoint rotation when required. 
       SUMMARY 
       [0008]    The use of such hollow shaft arrangements represents not only a high additional weight contribution but also leads to an increase in overall lengths and overall heights and to poorer efficiency of the transmission. 
         [0009]    It is therefore the underlying object of the invention to provide a dual clutch transmission which allows a large number of gears without enlarging the dimensions of the transmission and without significantly increasing the weight thereof. 
         [0010]    According to the invention, this object is achieved by virtue of the fact that an additional intermediate gearwheel set is provided, that one gearwheel of the intermediate gearwheel set is seated on the first or second intermediate shaft, that the other gearwheel of the intermediate wheel set is arranged on a third intermediate shaft, and that a third output gearwheel, which meshes with one of the output gearwheels of the first or second intermediate shaft, is seated on the third intermediate shaft. 
         [0011]    The intermediate gearwheel set can be selectively combined with all the gears, wherein the intermediate gearwheel set acts as a multiplier, i.e. the gears that can be selected via the first and/or second intermediate shaft can be doubled by means of the intermediate gearwheel set and the intermediate shaft. Thus, the third output gearwheel seated on the third intermediate shaft then meshes with one of the two output gearwheels of the first or second intermediate shaft, which gearwheels must co-rotate freely on the intermediate shafts thereof in this position in order to avoid producing an interlock between the third output gearwheel and the first or second output gearwheel. 
         [0012]    It is preferable if all the gearwheels arranged on the first and second intermediate shafts are designed as freely rotating wheels, wherein at least the coupling devices provided for the output gearwheels of the first and second intermediate shafts are of double-acting design. 
         [0013]    By means of this coupling device, it is thus possible for both the corresponding output gearwheel and the gearwheel adjacent to the output gearwheel to be connected for conjoint rotation to the corresponding intermediate shaft, or both adjacent gearwheels can be released in an intermediate position in order to co-rotate freely. 
         [0014]    When the power flows via the third intermediate shaft, the output gearwheels of the first intermediate shaft and of the second intermediate shaft must be decoupled and co-rotate freely on the respective intermediate shaft thereof. 
         [0015]    It is expedient if the gearwheel of the additional intermediate gearwheel set which is seated on the first intermediate shaft or the second intermediate shaft can be selectively connected for conjoint rotation to the intermediate shaft thereof or released therefrom. 
         [0016]    As an alternative, however, it is also possible for the third output gearwheel, which is arranged on the third intermediate shaft, to be selectively connected for conjoint rotation to the third intermediate shaft or released therefrom by means of a coupling device. 
         [0017]    The transmission according to the invention may have four wheel sets and one intermediate wheel set. 
         [0018]    If the transmission is provided with four wheel sets, for example, at least five coupling devices should be provided. 
         [0019]    In a preferred illustrative embodiment of the transmission having four wheel sets, there are six coupling devices. 
         [0020]    Eleven forward gears and two reverse gears can be selected by means of the transmission according to the invention. 
         [0021]    The 1st, 2nd, 9th and 11th forward gears can pass as winding path gears via the first intermediate shaft and the second intermediate shaft. 
         [0022]    The 3rd, 6th, 7th and 8th forward gears can expediently be selected as basic gears via the first intermediate shaft or the second intermediate shaft. 
         [0023]    The 4th and 5th forward gear can, in turn, be selected as winding path gears via the first or second intermediate shaft and via the third intermediate shaft. 
         [0024]    The 10th forward gear can, in turn, be selected as a winding path gear via the first intermediate shaft and the second intermediate shaft in combination with the third intermediate shaft. 
         [0025]    The two reverse gears are selected as winding path gears via the first intermediate shaft and the second intermediate shaft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The invention is illustrated by way of example in the drawing and described below in detail with reference to the drawing, in which: 
           [0027]      FIG. 1 : shows an illustrative embodiment of the dual clutch transmission according to the invention, 
           [0028]      FIG. 2 : shows the shift pattern for the 1st gear, 
           [0029]      FIG. 3 : shows the shift pattern for the 2nd gear, 
           [0030]      FIG. 4 : shows the shift pattern for the 3rd gear, 
           [0031]      FIG. 5 : shows the shift pattern for the 4th gear, 
           [0032]      FIG. 6 : shows the shift pattern for the 5th gear, 
           [0033]      FIG. 7 : shows the shift pattern for the 6th gear, 
           [0034]      FIG. 8 : shows the shift pattern for the 7th gear, 
           [0035]      FIG. 9 : shows the shift pattern for the 8th gear, 
           [0036]      FIG. 10 : shows the shift pattern for the 9th gear, 
           [0037]      FIG. 11 : shows the shift pattern for the 10th gear, 
           [0038]      FIG. 12 : shows the shift pattern for the 11th gear, 
           [0039]      FIG. 13 : shows the shift pattern for the 1st reverse gear, 
           [0040]      FIG. 14 : shows the shift pattern for the 2nd reverse gear, 
           [0041]      FIG. 15 : shows a tabular summary of the shift pattern for eleven forward gears and two reverse gears. 
       
    
    
     DETAILED DESCRIPTION 
       [0042]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0043]    The dual clutch transmission  1  illustrated in  FIG. 1  comprises four wheel sets for the forward gears, which are provided with numbers  1  to  4  enclosed by square borders, and a wheel set “R” for the reverse gears. In addition, two friction clutches  2  and  3  known per se are provided, said clutches transmitting the power flow supplied by an engine  4  selectively to two transmission input shafts. The transmission input shafts are designed as an inner shaft  5  and an outer shaft  6 , wherein the inner shaft  5  extends coaxially through the outer shaft  6 . 
         [0044]    The inner shaft  5  projects by a certain amount from the outer shaft  6  within the transmission case (not shown in the drawing), wherein two gearwheels  11  and  17  connected for conjoint rotation to the inner shaft  5  are arranged on the end of the inner shaft  5  which projects from the outer shaft  6 . Two further gearwheels  7  and  8  are likewise arranged for conjoint rotation on the outer shaft  6 . 
         [0045]    A first intermediate shaft  13  and a second intermediate shaft  14  are furthermore provided, on which shafts gearwheels are likewise arranged. The gearwheels arranged on the intermediate shafts  13  and  14  are rotatably mounted on the intermediate shafts  13 ,  14  and can be connected for conjoint rotation to the intermediate shafts  13  and  14  by means of coupling devices according to the selection of the desired gear. 
         [0046]    Four gearwheels are rotatably mounted on the first intermediate shaft  13 , namely a gearwheel  24 , which is in engagement with the gearwheel  8  arranged on the outer shaft  6 , a gearwheel  19 , which meshes with the gearwheel  17  seated on the inner shaft  5 , and a gearwheel  12  for the reverse gear, which is in engagement with a gearwheel  15  seated for conjoint rotation on the second intermediate shaft  14 . 
         [0047]    An output gearwheel  26 , which is in engagement with the differential gearwheel  23 , is seated on the first intermediate shaft  13 , on the right-hand side in the drawing. 
         [0048]    Three coupling devices  27 ,  20  and  35 , which are of double-acting design, are arranged between these four gearwheels  12 ,  19 ,  24  and  26  mounted rotatably on the first intermediate shaft  13 . Three shift positions are possible for these three coupling devices, namely to the right, to the left and in a central zero position, in which none of the loosely arranged adjacent gearwheels on both sides are coupled. 
         [0049]    Situated on the second intermediate shaft  14  is the gearwheel  15  already mentioned, which is arranged at the left-hand end of the second intermediate shaft  14 , a gearwheel  10 , which is in engagement with the gearwheel  11  arranged for conjoint rotation on the inner shaft  5 , and another rotatably mounted gearwheel  9 , which meshes with the gearwheel  7  arranged for conjoint rotation on the outer shaft  6 . 
         [0050]    At the right-hand end of the second intermediate shaft  14  there is an output gearwheel  21 , which, like the output gearwheel  26  arranged on the first intermediate shaft  13 , meshes with the differential gearwheel  23 . 
         [0051]    Also provided is an additional intermediate gearwheel set  25 , of which one gearwheel  30  is seated on the second intermediate shaft  14  and another gearwheel  29  is seated on a third intermediate shaft  31 . While the gearwheel  29  arranged on the third intermediate shaft  31  is connected for conjoint rotation to the third intermediate shaft  31 , the gearwheel  30  of the intermediate gearwheel set  25  is mounted rotatably on the second intermediate shaft  14 . 
         [0052]    Arranged between the gearwheels  21 ,  9 ,  10 ,  21  and  30  mounted rotatably on the second intermediate shaft  14  there is in each case a coupling device  18 ,  16  and  22 , which, like the coupling devices arranged on the first intermediate shaft  13 , is of double-acting design. Thus, for example, the output gearwheel  21  arranged on the second intermediate shaft  14  can be connected for conjoint rotation or released by means of coupling device  22 . The same applies to the adjacent gearwheel  9 , which can likewise be connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22  or is released in the decoupled state. In the central position of the coupling device  22 , both gearwheel  9  and the output gearwheel  21  are rotatable and can co-rotate freely. Corresponding statements apply to coupling devices  16  and  18  and the gearwheels dependent thereon. 
         [0053]    In addition to the gearwheel  29  arranged in a fixed manner, a third output gearwheel  32  is provided on the third intermediate shaft  31 , said output gearwheel being positioned for conjoint rotation on the third intermediate shaft  31  in the illustrative embodiment shown in the drawing. The illustrated embodiment of the third intermediate shaft  31  with the two gearwheels  29  and  32  arranged in a fixed manner represents a very simple and uncomplicated embodiment. 
         [0054]    As an alternative, it would, of course, also be possible to fix gearwheels  29  and  32  for conjoint rotation or release said gearwheels by means of coupling devices that are not shown in the drawing. In this case, the gearwheel  30  of the intermediate gearwheel set  25  which is seated on the second intermediate shaft  14  could then be connected for conjoint rotation to its intermediate shaft  14 . In some circumstances, it might then be possible to dispense with coupling device  18 . 
         [0055]    By means of the transmission illustrated in  FIG. 1 , it is possible to select eleven forward gears and two reverse gears, wherein the gears can in some cases be selected as simple basic gears, in some cases as basic gears via the third intermediate shaft  31  or in some cases as winding path gears via more than one intermediate shaft. 
         [0056]    In the following  FIGS. 2 to 14 , the individual selected gears are illustrated, wherein the power flow has in each case been made clear by depicting the participating shafts, gearwheels and coupling devices in thick lines, while the inactive transmission components are illustrated in the form of thin lines. 
         [0057]      FIG. 2  illustrates the 1 st  gear, which is selected as a winding path gear. The power flow passes from the engine  4 , via friction clutch  2  and the inner shaft  5 , wherein the gearwheel  17  seated at the left-hand end of the inner shaft  5  meshes with gearwheel  19 , which is seated on the first intermediate shaft  13  and is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  35 . 
         [0058]    Gearwheel  24 , which is likewise seated on the first intermediate shaft  13  and which meshes with gearwheel  8 , which is seated on the outer shaft  6 , is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  20  and thus transmits the torque to the freely corotating outer shaft  6  via gearwheel  8 . Gearwheel  7 , which is likewise seated on the outer shaft  6  and is connected for conjoint rotation thereto, transmits the torque to gearwheel  9 , which is seated on the second intermediate shaft  14  and which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  16 . 
         [0059]    Output gearwheel  21 , which is likewise seated on the second intermediate shaft  14 , is likewise connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22  and consequently transmits the power flow to the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0060]      FIG. 3  illustrates the selection of the 2 nd  gear, which once again passes as a winding path gear via the two intermediate shafts  13  and  14 . 
         [0061]    In this shift position, the power flow is transmitted from the engine  4  to the outer shaft  6  via friction clutch  3 . In this case, gearwheel  7 , which is seated on the outer shaft  6 , meshes with gearwheel  9 , which is seated on the second intermediate shaft  14  and which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  16  and thereby drives the intermediate shaft  14 . 
         [0062]    Gearwheel  10 , which is likewise seated on the second intermediate shaft  14  and which, like gearwheel  9 , is connected for conjoint rotation to the second intermediate shaft  14 , by means of coupling device  18 , meshes with gearwheel  11 , which is seated on the freely corotating inner shaft  5  and which thereby drives the inner shaft  5 . Here, gearwheel  17 , which is furthermore seated on the inner shaft  5 , meshes with gearwheel  19 , which is seated on the first intermediate shaft  13  and which is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  35 , whereby the first intermediate shaft  13  is driven. 
         [0063]    In this shift position, output gearwheel  26 , which is seated on the first intermediate shaft  13 , is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  27  and thus transmits the torque of the first intermediate shaft  13  to the differential gearwheel  23 . 
         [0064]      FIG. 4  illustrates the shift position for the 3 rd  gear, which can be selected as a simple basic gear. In this case, the power flow coming from the engine  4  is transmitted by friction clutch  2  to the inner shaft  5  and, from there, via gearwheel  17 , which is seated at the left-hand end of the inner shaft  5 , to gearwheel  19 , which is seated on the first intermediate shaft  13  and which is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  35 . In this shift position, the output gearwheel  26 , which is also seated on the first intermediate shaft  13 , is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  27 , with the result that the power flow is transmitted directly from the output gearwheel  26  to the differential gearwheel  23 . 
         [0065]      FIG. 5  illustrates the shift position of the 4 th  gear. The 4 th  gear is once again a basic gear but involves the intermediate gearwheel set  25 . 
         [0066]    The power flow starting from the engine  4  is transmitted via friction clutch  3  to the outer shaft  6  and, from there, via gearwheel  7 , to gearwheel  9 , which is seated on the second intermediate shaft  14  and which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22 . From the second intermediate shaft  14 , the power flow is then transmitted via the intermediate gearwheel set  25  to the third intermediate shaft  31 , namely via gearwheel  30 , which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  18  and transmits the torque via gearwheel  29  to the third intermediate shaft  31 . 
         [0067]    In this case, the third output gearwheel  32 , which is seated in a fixed manner on the third intermediate shaft  31 , meshes with output gearwheel  21 , which is seated loosely on the second intermediate shaft  14  and which transmits the power flow from the third intermediate shaft  31  to the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0068]      FIG. 6  shows the shift pattern of the 5 th  gear, which is once again a basic gear involving the intermediate gearwheel set  25 . 
         [0069]    In this case, the power flow is transmitted from the engine  4  to the inner shaft  5  via friction clutch  3 . Here, gearwheel  11 , which is seated on the inner shaft  5 , meshes with gearwheel  10 , which is seated on the second intermediate shaft  14  and which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  16 . 
         [0070]    From the second intermediate shaft  14 , the power flow passes via the intermediate gearwheel set  25  to the third intermediate shaft  31 , more specifically, during this process, gearwheel  30 , which is seated on the second intermediate shaft  14  is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  18  and transmits its torque to the third intermediate shaft  31  via gearwheel  29 . Here, output gearwheel  32 , which is seated in a fixed manner on the third intermediate shaft  31  meshes with output gearwheel  21 , which is seated loosely on the second intermediate shaft  14  and which meshes with the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0071]      FIG. 7  illustrates the shift pattern of the 6 th  gear, which is once again selected as a simple basic gear. Here, the power flow passes from the engine  4  via friction clutch  3  to the outer shaft  6  and, from there, via gearwheel  7  and gearwheel  9 , which meshes with the latter, to the second intermediate shaft  14 . Here, gearwheel  9  is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  16 . In the same way, output gearwheel  21 , which is seated on the second intermediate shaft  14 , is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22  and transmits the power flow directly to the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0072]    The shift pattern of the 7 th  gear, which is illustrated in  FIG. 8 , once again corresponds to a simple basic gear, wherein the power flow passes from the engine  4  to the inner shaft  5  via friction clutch  2 . From gearwheel  11 , which is arranged for conjoint rotation on the inner shaft  5 , the power flow passes to the second intermediate shaft  14 , more specifically gearwheel  11  on the inner shaft  5  meshes with gearwheel  10  on the second intermediate shaft  14 , wherein gearwheel  10  is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  18 . The second output gearwheel  21 , which is seated on the second intermediate shaft  14 , is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22  and once again transmits its torque directly to the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0073]      FIG. 9  illustrates the shift pattern of the 8 th  gear, which can once again be selected as a simple basic gear, more specifically the power flow passes from the engine  4  to the outer shaft  6  via friction clutch  3 . In this case, gearwheel  8 , which is seated for conjoint rotation at the left-hand end of the outer shaft  6 , meshes with gearwheel  24 , which is seated on the first intermediate shaft  13  and which is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  20 . 
         [0074]    Output gearwheel  26 , which is seated on the first intermediate shaft  13 , is likewise connected for conjoint rotation to the first intermediate shaft  13  by its coupling device  27  and thus transmits the torque directly to the differential gearwheel  23 . 
         [0075]      FIG. 10  illustrates the shift pattern of the 9 th  gear, which is selected as a winding path gear, more specifically the power flow passes from the engine  4 , via friction clutch  2 , to the inner shaft  5 , from there, via gearwheel  11 , to gearwheel  10 , which is seated on the second intermediate shaft  14  and which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  16 . 
         [0076]    From the second intermediate shaft  14 , the power flow is transmitted via gearwheel  9 , which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22 , to gearwheel  7  of the outer shaft  6 , which in this case idly corotates. Gearwheel  8 , which is likewise seated on the outer shaft  6 , then transmits the power flow to the first intermediate shaft  13  via gearwheel  24 , wherein gearwheel  24  is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  20 . 
         [0077]    In this case, output gearwheel  26 , which is seated on the first intermediate shaft  13 , is likewise connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  27 , allowing output gearwheel  26  to transmit the torque directly to the differential gearwheel  23 . 
         [0078]      FIG. 11  illustrates the shift pattern for the 10 th  gear, this being a winding path gear involving the intermediate gearwheel set  25 . 
         [0079]    In this case, the power flow starting from the engine  4  is transmitted to the outer shaft  6  via friction clutch  3 . From the outer shaft  6 , the power flow passes via gearwheel  8 , which is seated at the left-hand end of the outer shaft  6 , and coupled gearwheel  24 , which is seated on the first intermediate shaft  13 , to the first intermediate shaft  13  and, from there, via the coupled gearwheel  19  on said shaft and gearwheel  17 , which meshes with the latter gearwheel, of the freely corotating inner shaft  5 . 
         [0080]    Gearwheel  11 , which is likewise seated on the inner shaft  5 , transmits the power flow via the coupled gearwheel  10  to the second intermediate shaft  14  and, from there, the power flow passes via the intermediate gearwheel set  25  to the third intermediate shaft  31  since the coupled gearwheel  30  of the second intermediate shaft  14  meshes with gearwheel  29 , which is seated for conjoint rotation on the third intermediate shaft  31 . 
         [0081]    Output gearwheel  32 , which is seated at the right-hand end of the third intermediate shaft  31 , then transmits the torque to output gearwheel  21 , which corotates freely on the second intermediate shaft  14  and which meshes with the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0082]    The 11 th  gear, which is illustrated in  FIG. 12 , is once again a winding path gear, although it does not involve the intermediate gearwheel set  25 . 
         [0083]    The power flow passes from the engine  4  via friction clutch  3  to the outer shaft  6 , from there, via gearwheel  8 , to the coupled gearwheel  24  of the first intermediate shaft  13  and, from there, via the coupled gearwheel  19 , to gearwheel  17 , which is seated on the freely corotating inner shaft  5 , and, from there, the torque is transmitted via gearwheel  11 , which is likewise seated on the inner shaft  5 , to gearwheel  10 , which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  16 . 
         [0084]    Output gearwheel  21 , which is seated on the second intermediate shaft  14  and is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22  then transmits the torque to the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0085]      FIGS. 13 and 14  illustrate the shift patterns of the two reverse gears, which are designed as winding path gears, wherein, according to  FIG. 13 , the power flow of the first reverse gear passes from the inner shaft  5 , via the first intermediate shaft  13  to the second intermediate shaft  14  and, from the second intermediate shaft  14 , output gearwheel  21 , which is connected for conjoint rotation to the second intermediate shaft  14  by means of coupling device  22 , transmits the torque to the differential gearwheel  23 , as indicated by the dashed arrow  33 . 
         [0086]    According to  FIG. 14 , the power flow passes from the outer shaft  6  to the first intermediate shaft  13  via the second intermediate shaft  14 , wherein gearwheel  15 , which is seated in a fixed manner on the second intermediate shaft  14 , meshes with the coupled gearwheel  12  of the first intermediate shaft  13 . 
         [0087]    The output gearwheel  26  of the first intermediate shaft  13  is connected for conjoint rotation to the first intermediate shaft  13  by means of coupling device  27  and transmits its torque directly to the differential gearwheel  23 . 
         [0088]    By means of the transmission according to the invention, which manages with four wheel sets and six coupling devices as well as one intermediate wheel set, it is thus possible to select eleven forward gears and two reverse gears, wherein the total weight of the transmission and the dimensions thereof can be kept extremely small. 
         [0089]      FIG. 15  illustrates once again the shift pattern for all the gears, eleven forward gears and two reverse gears. Here, the two left-hand columns indicate which of the two friction clutches  2  and  3  is closed or open, wherein the number 1 indicates the closed state and the number 0 indicates the open state. In the central area, the shift positions of the six coupling devices are illustrated, wherein the letter “R” is intended to represent the right-hand shift position, the letter “L” is intended to represent the left-hand shift position and “0” is intended to represent the uncoupled shift position. 
         [0090]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.