Abstract:
A shiftable multispeed reverse transmission having one input shaft ( 1 ) and a plurality of countershafts ( 2, 3, 4, 5, 6, 7 ) and one output shaft ( 8 ). One of gears and/or idle gears being situated upon the countershafts ( 2, 3, 4, 5, 6, 7 ) for non-rotatably connection with the countershafts, via shiftable clutches, for gear and direction change. The reduction ratios being generated by spur pinion stages and at least one shiftable planetary stage (P).

Description:
This application is a national stage completion of PCT/EP2004/014202 filed Dec. 14, 2004 which claims priority from German Application Serial No. 10 2004 002 969.5 filed Jan. 21, 2004. 
   FIELD OF THE INVENTION 
   This invention relates to a multispeed manual transmission comprising one input shaft, countershafts, gears and/or idle gears non-rotatably connectable via shifting clutches with the countershafts for gear or direction change being disposed upon the countershafts and one output shaft. 
   BACKGROUND OF THE INVENTION 
   The transmissions that are usually employed in dumpers, loaders, excavation loaders and lift trucks, and also used in vehicles operated on the road such as mobile cranes. Here are involved, as a rule, powershift transmission with front-mounted hydrodynamic torque converters where a continuous and automatic torque increase can be obtained during an increase of the working resistance of the motor vehicle such as a construction machine. Driving torques of the transmission can be produced driving torques of the transmission which correspond to about a triple value of the motor torque. 
   The power flow in the individual gears of a transmission of the above mentioned kind is produced by a combination of the hydraulically shiftable clutches. The clutches must be shiftable under load for the reversal in loaders, among others, and therefore, can absorb much energy. The design of the housing and the arrangement of the shafts of the transmission must be adapted to the application. 
   Within the scope of the Applicant&#39;s EP 0 759 129 B1 is described a multispeed reverse transmission shiftable under load having at least one input shaft, countershafts and gears which form an input gearset and shifting clutches situated on the countershafts with idle gears which can optionally be no-rotatably connected with one of the countershafts for gear and direction change. One fixed gear and idle gears in constant mesh therewith form the input gearset; in addition, one fixed gear situated on a countershaft and inconstant mesh with two idle gears form an output gear chain; the countershafts are interconnected byfixed gears and one idle gear. Another such transmission is the object of the Applicant&#39;s EP 0 796 400 B1. 
   The problem on which this invention is based is to outline a shiftable multispeed reverse transmission having a higher power compared to the prior art. Besides, the inventive transmission must have good efficiency and be sturdy. 
   SUMMARY OF THE INVENTION 
   Accordingly, a transmission shiftable under load is proposed which comprises one input shaft, countershafts, gears and/or idle gears non-rotatably connected with the countershafts, via shifting clutches, for gear and direction change being located on the countershafts, and one output shaft, the reduction ratio is generated by spur pinion stages and at least one shiftable planetary stage. 
   According to the invention, depending on the clutch states, two power lows are produced which respectively meet on the same fixed gear. The planetary stage is preferably in power flow direction located between the fixed gear and the output shaft. Depending on the transmission version, the transmission can be designed as a four-gear or as an eight-gear 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  is a diagram of an inventive transmission especially adequate for a loader; 
     FIG. 1A  is a representation of the gear numbers corresponding to the transmission of  FIG. 1 ; 
     FIG. 2  is a diagram of an inventive transmission especially adequate for a dumper; 
     FIG. 2A  is a representation of the gear numbers corresponding to the transmission of  FIG. 2 ; and 
     FIG. 3  is a preferred embodiment of the bearing arrangement for the shaft having the planetary stage. 

   DETAILED DESCRIPTION OF THE INVENTION 
   The transmission shown in  FIG. 1 , which is especially adequate for a loader, comprises one input shaft  1  upon which is situated one powershift clutch KV (forward clutch) by way of which an idle gear  115  can be non-torsionally connected with the input shaft  1 . Upon the shaft  1  is, in addition, provided with one fixed gear  116 , which is in constant mesh with a fixed gear  202  of a countershaft  2 . Upon the countershaft  2  is provided one powershift clutch KR (reverse clutch) which loosely non-torsionally connects an idle gear  102  with the countershaft  2 . The idle gear  102  and the idle gear  115  of the input shaft are in constant mesh with a fixed gear  104  upon a countershaft  4 ; upon the countershaft  4  are additionally provided one idle gear  111  non-torsionally connectable with the countershaft  4  via a clutch K 2  and one fixed gear  204 , the idle gear  111  being in constant mesh with a fixed gear  106  located upon a countershaft  6  and the fixed gear  204  is in constant mesh with an idle gear  113  situated upon the countershaft  6 . As is to be understood from  FIG. 1 , the idle gear  113  can be non-torsionally connected via a clutch K 4  with the countershaft  6 . 
   The fixed gear  106  of the countershaft  6  is in constant mesh with a fixed gear  107  located on a countershaft  7 . Upon the shaft  7  is provided one idle gear  117  which is in constant mesh with one fixed gear  108  situated on an output shaft  8 . According to the invention, in power flow direction between the fixed gear  107  and the fixed gear  108  of the output shaft  8 , a shiftable planetary stage P is situated, the sun gear of which is non-torsionally connected with the countershaft  7 . One brake B is provided which connects a hollow gear H with a housing G. In addition, two components of the planetary stage, preferably the sun gear with the hollow gear, are loosely interconnectable via a clutch K. If the brake B is now engaged and the clutch K open, the power is then transmitted from the fixed gear  107 , via the planetary stage P to the idle gear  117 . On the other hand, when the brake B is disengaged and the clutch K engaged, the power is directly transmitted from the fixed gear  107  to the idle gear  117  without any change of ratio. (The planetary stage rotates in the block operation.) 
   This transmission has fourforward and four reverse gears, two other shifting elements in two power flows being each alternatively actuated to implement the gears when the forward clutch KV is engaged for the forward gears and the reverse clutch KR for the reverse gears. The clutches KR and KV suffice to meet the reversal requirements placed on a loader, since they can be shifted under load. For the first forward gear, together with the clutch KV, the clutch K 2  and the brake B are engaged, the gears  115 ,  104 ,  111 ,  106 ,  107 , planetary stage,  117  and  108  transmitting the power to the output shaft. The second forward gear results by engaging the brake B and the clutch K 4 ; the power is transmitted by the gears  115 ,  104 ,  204 ,  113 ,  106 ,  107 , planetary stage,  117  and  108  to the output shaft. For the third forward gear, the clutches K 2  and K are engaged, the gears  115 ,  104 ,  111 ,  106 ,  107 ,  117  and  108  transmitting the power to the output shaft  8 . To engage the fourth forward gear, the clutches K 4  and K are engaged so that the power is transmitted via the gears  115 ,  104 ,  204 ,  113 ,  106 ,  107 ,  117  and  108  to the output shaft  8 . 
   For the reverse gears, the clutch KR is engaged. The first reverse gear results here by engaging the clutch K 2  and of the brake B; the power is transmitted from the input shaft  1  via the gears  116 ,  202 ,  102 ,  104 ,  111 ,  106 ,  107 , planetary stage,  117  and  108  to the output shaft  8 . The second reverse gear results by engaging the clutch K 4  and of the brake B, the power being transmitted via the gears  116 ,  202 ,  102 ,  104 ,  204 ,  113 ,  106 ,  107 , planetary stage,  117  and  108  to the output shaft  8 . According to the invention, the third reverse gear is engaged by engaging the clutches K 2  and K, the power being transmitted via the gears  116 ,  202 ,  102 ,  104 ,  111 ,  106 ,  107 ,  117  and  108  to the output shaft  8 . Finally, for the fourth reverse gear, the clutches K 4  and K are engaged; the gears  116 ,  202 ,  102 ,  104 ,  204 ,  113 ,  106 ,  107 ,  117  and  108  transmitting the power to the output shaft  8 . 
   According to the invention, therefore, depending on the clutch states two power flows can be produced which meet on the same fixed gear  107 , the fixed gear not being situated upon the output shaft  8 . 
   By substituting for the clutches KV and KR through input shaft  1 , two synchronizer units or dog clutches SV and SR and adding two other countershafts  3  and  5  with corresponding gears and clutches, an eight gear transmission advantageously results which is especially adequate for dumpers. 
   One such transmission is the object of  FIG. 2 . The eight-gear transmission accordingly differs from the transmission shown in  FIG. 1  by the fact that upon the countershaft  2 , no shifting element is situated and that upon the input shaft, instead of the clutch KV, two synchronizer units or dog clutches SV and SR are placed (respectively for the forward and reverse gears, it being possible to shift when the vehicle is stopped). The synchronizer units or dogs can be designed as double or single synchronizer units or also as dog clutches. Further provided is one other countershaft  3  which has two fixed gears  103  and  203  and one idle gear  110  non-torsionally connectable with the countershaft  3  via a clutch K 1  provided on the countershaft  3 , the fixed gear  103  being in constant mesh with the idle gear  115  of the input shaft  1 . 
   One other countershaft  5  is, in addition, provided having one fixed gear  105  which is in constant mesh with the idle gear  110  of the countershaft  3  and one idle gear  112  non-torsionally connectable with the countershaft  5  via a clutch K 3  provided on the countershaft  5 . The idle gear  112  is here in constant mesh with the fixed gear  203  of the countershaft  3 ; the fixed gear  105  is in constant mesh with the fixed gear  107  disposed on the countershaft  7 . 
   To implement the eighth forward and eighth reverse gears, when the clutches SV and SR, respectively, for the forward and reverse gears are engaged, each two other shifting elements are alternatively actuated in two power flows. 
   The first gear of the transmission, according to  FIG. 1 , corresponds here to the second gear, the second gear of the transmission to  FIG. 1  to the fourth gear, the third gear of the transmission, according to  FIG. 1 , to the sixth gear and the fourth gear of the transmission, according to  FIG. 1 , to the eighth gear. 
   Accordingly, the first forward gear results by engaging the SV, of the clutch K 1  and of the brake B; the power is transmitted by the gears  115 ,  103 ,  110 ,  105 ,  107 , planetary stage,  117  and  108 . For the second forward gear, the clutch K 2  of the brake B are engaged, the gears  115 ,  104 ,  111 ,  106 ,  107 , planetary stage,  117  and  108  transmitting the power to the output shaft. In the third forward gear, the clutch K 3  and the brake B are engaged and the power is transmitted by the gears  115 ,  103 ,  203 ,  112 ,  105 ,  107 , planetary stage,  117  and  108 . The fourth forward gear results by engaging the brake B and of the clutch K 4 ; the power is transmitted by the gears  115 ,  103 ,  203 ,  112 ,  105 ,  107 , planetary stage,  117  and  108  to the output shaft. In the fifth gear, the clutches K 1  and K are engaged, the power being transmitted by the gears  115 ,  103 ,  110 ,  105 ,  107 ,  117  and  108  to the output shaft  8 . According to  FIG. 2 , for the sixth forward gear the clutches K 2  and K are engaged, the gears  115 ,  104 ,  111 ,  106 ,  107 ,  117  and  108  transmitting the power to the output shaft  8 . In addition, the seventh forward gear results by engaging the clutches K 3  and K; the power is transmitted by the gears  115 ,  103 ,  203 ,  112 ,  105 ,  107 ,  117  and  108 . To engage the eighth forward gear, the clutches K 4  and K are engaged so that the power is transmitted via the gears  115 ,  104 ,  204 ,  113 ,  106 ,  107 ,  117  and  108  to the output shaft  8 . 
   The first reverse gear results by engaging the synchronizer unit of the clutch K 1  and of the brake B; the power is here transmitted by the gears  116 ,  202 ,  102 ,  104 ,  115 ,  103 ,  110 ,  105 ,  107 , planetary stage,  117  and  108  to the output shaft  7 . The second reverse gear is engaged by engaging the clutch K 2  and the brake B; the power is transmitted from the input shaft  1  via the gears  116 ,  202 ,  102 ,  103 ,  111 ,  106 ,  107 , planetary stage,  117  and  118  to the output shaft  8 . In the third reverse gear, the clutch K 3  and the brake B are engaged so that the power is transmitted via the gears  116 ,  202 ,  102 ,  104 ,  115 ,  103 ,  203 ,  112 ,  105 ,  107 , planetary stage,  117 ,  108 . The fourth reverse gear results by engaging the clutch K 4  and the brake B, the power being transmitted via the gears  116 ,  202 ,  102 ,  104 ,  204 ,  113 ,  106 ,  107 , planetary stage,  117  and  108  to the output shaft  8 . 
   In addition, the fifth reverse gear results by engaging the clutches K 1  and K, the power being transmitted by the gears  116 ,  202 ,  102 ,  104 ,  115 ,  103 ,  110 ,  105 ,  107 ,  117  and  108 . According to the invention, the sixth reverse gear is engaged by engaging the clutches K 2  and K, the power being transmitted via the gears  116 ,  202 ,  102 ,  104 ,  111 ,  106 ,  107 ,  117  and  108  to the output shaft  8 . In the seventh gear, the clutches K 3  and K are engaged the power being transmitted by the gears  116 ,  202 ,  102 ,  104 ,  115 ,  103 ,  203 ,  112 ,  105 ,  107 ,  117  and  108 . Finally, the clutches K 4  and K are engaged for the eighth reverse gear; the gears  116 ,  202 ,  102 ,  104 ,  204 ,  113 ,  106 ,  107 ,  117  and  108  here transmit the power to the output shaft  8 . 
   The ratio of the planetary stage is preferably selected so that in the shaft  4 - 5  in the eighth gear or  2 - 3  in the fourth gear for the transmission, according to  FIG. 1 , a uniform ratio range is achieved. One clutch takes part in each open flow up to the fixed gear  7 . 
   In  FIG. 3 , a specially advantageous bearing arrangement for the countershaft  7  is shown. In the prior art, for the countershaft  7  having the planetary stage P, a costly support is needed in which, on four bearing points, housing walls are concentrated on the bearings so as to transmit the forces. The bearings are inventively arranged so that one bearing point can be eliminated in the housing. 
   The countershaft  7  is deposited in the transmission housing with a bearing A 07  and in a hollow shaft  17  with a bearing B 07 . Radial forces are transmitted, on one hand, from the bearing A 07  directly to the housing and, on the other hand, from bearing B 07 , via a bearing B 17 , to the housing. From the Figure is to be understood that the hollow shaft  17  is deposited with a bearing A 17  on the countershaft  7  and with the bearing B 17  in the housing. The radial forces of the bearing A 17  are proportionately transmitted from the bearings A 07  and B 07  via bearing B 17  to the housing; radial forces of the bearing B 17  are directly supported in the housing. 
   In addition, axial forces are transmitted from the shaft  7 , via the bearing A 17 , to the hollow shaft  17  and from hollow shaft  17 , via the bearing A 07 , to the countershaft  7 . The axial forces can thus be always assisted in the housing by the bearings A 07  and B 17 . By virtue of the arrangement of the bearing B 07  in the active line of the bearing B 17 , no added tilting forces act upon the bearing system. 
   In the inventive embodiment, the output stage can be designed with a longitudinal differential (also disengageable). 
   The inventive idea makes available for dumpers or loaders transmission having good efficiency and able to transmit high powers. By the construction of the transmission, a great equality of parts can be obtained; most parts needed, except the powershift clutches KV and KR, can have the same construction. 
   Any structural design, especially any spatial arrangement of the countershafts, of the gears, of the planetary stage and of the shifting elements per se or relative to each other and insofar as technologically significant obviously fall also under the scope of protection of the instant claims without affecting the operation of the transmission such as outlined in the claims even if the designs have not been explicitly shown in the Figures or the description. 
   
     
       
             
           
             
             
             
           
         
             
                 
             
             
               Reference numerals 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
                1 
               input shaft 
             
             
                 
                2 
               countershaft 
             
             
                 
                3 
               countershaft 
             
             
                 
                4 
               countershaft 
             
             
                 
                5 
               countershaft 
             
             
                 
                6 
               countershaft 
             
             
                 
                7 
               countershaft 
             
             
                 
                8 
               output shaft 
             
             
                 
                17 
               shaft 
             
             
                 
               102 
               fixed gear or idle gear RL 
             
             
                 
               103 
               fixed gear 
             
             
                 
               104 
               fixed gear 
             
             
                 
               105 
               fixed gear 
             
             
                 
               106 
               fixed gear 
             
             
                 
               107 
               fixed gear 
             
             
                 
               108 
               fixed gear 
             
             
                 
               110 
               idle gear 
             
             
                 
               111 
               idle gear 
             
             
                 
               112 
               idle gear 
             
             
                 
               113 
               idle gear 
             
             
                 
               115 
               idle gear 
             
             
                 
               116 
               idle gear or fixed gear RL 
             
             
                 
               117 
               idle gear 
             
             
                 
               202 
               fixed gear 
             
             
                 
               203 
               fixed gear 
             
             
                 
               204 
               fixed gear 
             
             
                 
               KV 
               forward cutch 
             
             
                 
               KR 
               reverse clutch 
             
             
                 
               K1 
               clutch 
             
             
                 
               K2 
               clutch 
             
             
                 
               K3 
               clutch 
             
             
                 
               K5 
               clutch 
             
             
                 
               K 
               clutch 
             
             
                 
               B 
               brake 
             
             
                 
               G 
               housing 
             
             
                 
               P 
               planetary stage 
             
             
                 
               S 
               sun gear 
             
             
                 
               H 
               hollow gear 
             
             
                 
               SR 
               synchronizer unit or dog clutch 
             
             
                 
               SV 
               synchronizer unit or dog clutch 
             
             
                 
               A07 
               bearing 
             
             
                 
               A17 
               bearing 
             
             
                 
               B07 
               bearing 
             
             
                 
               B17 
               bearing