Abstract:
A powershifting multispeed reversing transmission includes a converter lockup clutch ( 31 ) arranged in a space ( 13 ) provided by arranging the forward-driving clutch ( 8 ) between the fixed gear ( 5 ) and the loose gear ( 7 ) on a forward-driving shaft, and the reverse-driving clutch ( 12 ) between the fixed gear ( 9 ) and the loose gear ( 11 ) a reverse-driving shaft.

Description:
[0001]    This application claims priority from German patent application serial no. 10 2016 207 299.4 filed Apr. 28, 2016. 
       FIELD OF THE INVENTION 
       [0002]    The invention concerns a powershift multispeed reversing transmission. 
       BACKGROUND OF THE INVENTION 
       [0003]    Powershifting multispeed reversing transmissions of the type concerned are used in working machines such as telehandlers or backhoe loaders and in smaller wheel loaders. In these vehicles the structural space above the driveshaft of the drive engine is needed for superstructures and for the cabin of the vehicle. However, in order to leave enough ground clearance a particular distance between the drive shaft and the drive output shaft of the transmission has to be maintained. Depending on their use, in vehicles of this type the drive engine in the vehicle is positioned at the rear or centrally, as is the case for example in smaller wheel loaders and also telehandlers. 
         [0004]    Frequently, the drive-trains of such vehicles include a hydrodynamic torque converter, which can have a so-termed converter lockup clutch in order to improve efficiency in the drive-train. 
         [0005]    DE4416930A1 discloses a powershifting reversing transmission with a converter lockup clutch arranged therein, which connects the pump impeller wheel to the turbine wheel. However, due to the arrangement of the clutches and shafts, this transmission is not suitable for smaller wheel loaders and telehandlers because it takes up considerable axial length. 
       SUMMARY OF THE INVENTION 
       [0006]    The purpose of the present invention is to provide a powershifting reversing transmission that takes up little axial length, allows the possibility of incorporating a converter lockup clutch, and leaves sufficient room for the arrangement of a cabin above the driveshaft. 
         [0007]    This objective is achieved with a powershifting transmission of the type concerned which also embodies the characterizing features specified in the principal claim. According to the invention, the powershifting multispeed reversing transmission has an input shaft that can be connected to a drive engine, for example an internal combustion engine. Coaxially with the input shaft is arranged a drive shaft which is functionally connected to the input shaft. When a hydrodynamic torque converter is used, the input shaft is connected in a rotationally fixed manner to the pump impeller wheel, and the drive shaft is connected in a rotationally fixed manner to the turbine wheel. However, the transmission can also be designed without the hydrodynamic torque converter, and in that case the input shaft is connected in a rotationally fixed manner to the drive shaft. A fixed gear is connected in a rotationally fixed manner to the driveshaft and meshes with a fixed gear on the shaft for forward driving and with a fixed gear on the shaft for driving in reverse. The fixed gear on the drive shaft is arranged close to the hydrodynamic torque converter. A clutch is arranged on the shaft for forward driving between the fixed gear and a loose wheel, and on the shaft for reverse driving a clutch is also arranged between the fixed gear and the loose wheel. This produces some fitting space between the clutch for forward driving and the clutch for reversing, into which a so-termed converter lockup clutch can be fitted inside the transmission on the drive shaft. This converter lockup clutch connects the input shaft to the drive shaft and, if a hydrodynamic torque converter is present, the pump impeller wheel to the turbine wheel. Since the converter lockup clutch is arranged at the height level of the clutches for forward and for reverse driving, the axial length of the transmission is not increased. Since the fixed gear on the drive shaft meshes with the fixed gear on the forward driving shaft and with the fixed gear on the reverse driving shaft, all the other shafts can be arranged below the drive shaft, so that above the drive shaft enough room remains, for example, for a cabin. The required flexibility in the axial distance from the drive shaft to the drive output shaft is achieved by varying the distance between the forward and reverse driving shafts. The other shafts are located under the shafts for forward and reverse driving. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further features emerge from the description of the figures, which show: 
           [0009]      FIG. 1 : A transmission layout according to the invention, with six forward gears and three reverse gears, without a converter lockup clutch 
           [0010]      FIG. 2 : The transmission layout of  FIG. 1 , with a converter lockup clutch 
           [0011]      FIG. 3 : A transmission layout according to the invention, with six forward gears and three reverse gears, without a converter lockup clutch 
           [0012]      FIG. 4 : The transmission layout of  FIG. 3 , with a converter lockup clutch 
           [0013]      FIG. 5 : The arrangement of the gearwheels for producing a small axial distance between the drive shaft and the drive output shaft in the above transmission layout 
           [0014]      FIG. 6 : The arrangement of the gearwheels for producing a larger axial distance between the drive shaft and the drive output shaft in the above transmission layout; and 
           [0015]      FIG. 7 : A section of a design form of the arrangement of the converter lockup clutch. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]      FIG. 1 . 
         [0017]    A drive engine (not shown), for example an internal combustion engine, drives the input shaft  1  of the transmission. The input shaft  1  is connected in a rotationally fixed manner to the pump impeller wheel of the hydrodynamic torque converter  2 . The turbine wheel of the hydrodynamic torque converter  2  is connected in a rotationally fixed manner to the drive shaft  3 . The drive shaft  3  is preferably in the form of a hollow shaft. The drive shaft  3  rotates about a rotational axis (not shown). The fixed gear  4  is connected in a rotationally fixed manner to the drive shaft  3 . ‘Fixed gear’ means that the gearwheel is connected in a rotationally fixed manner to the shaft or is made integrally with the shaft. The fixed gear  4  meshes with the fixed gear  5 , the fixed gear  5  is connected in a rotationally fixed manner to the shaft  6  for forward driving. On the forward driving shaft  6  is mounted to rotate a loose wheel  7 , where ‘loose wheel’ means that the gearwheel is fitted onto a shaft in such manner that it can rotate. By means of the forward-driving clutch  8  the loose wheel  7  can be connected in a rotationally fixed manner to the forward-driving shaft  6 . The fixed gear  4  meshes with the fixed gear  9 , which is connected in a rotationally fixed manner to the shaft  10  for reverse driving. The loose wheel  11  is mounted to rotate on the reverse-driving shaft  10  and can be connected to it in a rotationally fixed manner by means of the reverse-driving clutch  12 . The forward-driving clutch  8  is positioned between the fixed gear  5  and the loose wheel  7 , the reverse-driving clutch  12  is positioned between the fixed gear  9  and the loose wheel  11 , and the fixed gear  4 , the fixed gear  5  and the fixed gear  9  are arranged close to the hydrodynamic torque converter  2  and thus on the side of the transmission facing toward the drive engine, whereby a space  13  is formed between the forward-driving clutch  8  and the reverse-driving clutch  12 , and within the space a converter lockup clutch can be arranged if desired. The loose wheel  11  meshes with the fixed gear  14  arranged on the shaft  15 . The loose wheel  16  is also arranged on the shaft  15  and can be connected to the shaft  15  by means of the clutch  17  for first gear. The loose wheel  16  meshes with the fixed gear  18 , which is connected in a rotationally fixed manner to the drive output shaft  19 . The drive output shaft  19  drives a vehicle axle (not shown) of the vehicle. The fixed gear  18  meshes with the loose wheel  20 , which is mounted to rotate on the shaft  21  and can be connected to the shaft  21  by the clutch for second gear. The fixed gear  14  meshes with the fixed gear  23  and the fixed gear  24  meshes with the fixed gear  25 . The loose wheel  26  meshes with the fixed gear  25  and can be connected to the drive output shaft  19  by means of the clutch  27  for third gear. The fixed gears  23  and  24  are arranged on the shaft  28 , on which the loose wheel  29  is also mounted to rotate. The loose wheel  29  can be connected to the shaft  28  by means of the clutch  30  for fourth gear. 
         [0018]      FIG. 2 : 
         [0019]    The transmission layout shown in  FIG. 2  is identical to the transmission layout in  FIG. 1  except for the converter lockup clutch  31 . The converter lockup clutch  31  is arranged in the space  13 , and by means of the converter lockup clutch  31 , the input shaft  1  can be connected to the drive shaft  3  in order to bypass the hydrodynamic torque converter. Since the converter lockup clutch  31  is in the space  13 , the axial length of the transmission is not increased and the transmission can therefore be made either with or without a converter lockup clutch  31 . 
         [0020]      FIG. 3 : 
         [0021]      FIG. 3  differs from  FIG. 1  in that the fixed gear  24  is connected in a rotationally fixed manner to the shaft  28  in  FIG. 1 , whereas the fixed gear  24  is connected in a rotationally fixed manner to the shaft  21  in  FIG. 3 . Consequently, in  FIG. 1  the fixed gear  24  meshes with the fixed gear  25  whereas in  FIG. 3  the fixed gear  24  meshes with the fixed gear  23 . The other arrangements of the gearwheels and their engagements are identical. 
         [0022]      FIG. 4 : 
         [0023]    The design according to  FIG. 4  is identical to the design according to  FIG. 3 , except that in  FIG. 4  the converter lockup clutch  31  is arranged in the space  13 . As in  FIG. 2 , the converter lockup clutch  31  in  FIG. 4  can be functionally connected to the input shaft  1  and the drive shaft  3 . 
         [0024]      FIG. 5 : 
         [0025]    In the vehicle, the vehicle cabin  32  requires installation space above the input shaft  1 . By virtue of the transmission layout according to the invention, the shafts  6 ,  10 ,  15 ,  19 ,  21  and  28  can be positioned under the input shaft  1  so that a sufficient amount of structural space is available for the vehicle cabin. Since the forward-driving shaft  6  and the reverse-driving shaft  10  are arranged laterally and almost at the same level as the input shaft  1 , the axial distance between the input shaft  1  and the drive output shaft  19  can be made smaller, for example 450 mm. 
         [0026]      FIG. 6 : 
         [0027]    To produce a larger axial distance in the arrangement according to  FIG. 5 , the forward-driving shaft  6  and the reverse-driving shaft  10  are not arranged almost at the same height level as the input shaft  1  as in  FIG. 5 , but are axially a larger distance away from the input shaft  1 . This makes it possible to increase the axial distance up to 500 mm. 
         [0028]      FIG. 7 : 
         [0029]    To be able to fit the converter lockup clutch  31  in a space-saving manner and to enable the hydrodynamic torque converter  2  to be supplied with sufficient lubricant and coolant, the input shaft  1  is arranged inside the drive shaft  3  in such manner that there is a gap between the input shaft  1  and the drive shaft  3 . The fixed gear  4  is made integrally with the inner disk carrier of the converter lockup clutch  31  and mounted by means of a bearing  33  on the input shaft  1 . The coolant and lubricant medium passes to the hydrodynamic torque converter through the bore  34 . The outer disk carrier  35  is connected to the input shaft  1  in a rotationally fixed manner. 
       INDEXES 
       [0000]    
       
           1  Input shaft 
           2  Hydrodynamic torque converter 
           3  Drive shaft 
           4  Fixed gear 
           5  Fixed gear 
           6  Forward-driving shaft 
           7  Loose wheel 
           8  Forward-driving clutch 
           9  Fixed gear 
           10  Reverse-driving shaft 
           11  Loose wheel 
           12  Reverse-driving clutch 
           13  Space 
           14  Fixed gear 
           15  Shaft 
           16  Loose wheel 
           17  Clutch for the first gear 
           18  Fixed gear 
           19  Drive output shaft 
           20  Loose wheel 
           21  Shaft 
           22  Clutch for the second gear 
           23  Fixed gear 
           24  Fixed gear 
           25  Fixed gear 
           26  Loose wheel 
           27  Clutch for the third gear 
           28  Shaft 
           29  Loose wheel 
           30  Clutch for the fourth gear 
           31  Converter lockup clutch 
           32  Vehicle cabin 
           33  Bearing 
           34  Bore 
           35  Outer disk carrier