Abstract:
A transmission device ( 1 ) for a vehicle with a variator ( 3 ), a planetary gear unit ( 4 ) and a gearshift transmission unit ( 9 ). The variator ( 3 ) has a length which is greater than a width and a depth of the variator ( 3 ). When the variator ( 3 ) is installed in position in the vehicle, the length of the variator ( 3 ) is orientated at least approximately diagonally to the length of the vehicle.

Description:
[0001]    This application is a National Stage completion of PCT/EP2008/060754 filed Aug. 15, 2008, which claims priority from German patent application serial no. 10 2008 040 448.9 filed Jul. 16, 2008. 
       FIELD OF THE INVENTION 
       [0002]    The invention concerns a transmission device for a vehicle, comprising a variator, a planetary gear unit and a manual transmission unit. 
       BACKGROUND OF THE INVENTION 
       [0003]    A hydrostatic-mechanical tractor transmission with a continuously variable hydrostatic drive is known from DE 10 2006 025 348 A1. The hydrostatic drive comprises a hydrostatic pump powered by an internal combustion engine and a hydro-motor driven by the pump. The pump and hydro-motor are force-coupled by a single, common pivoting component and can be adjusted in such manner that the pump can pivot between a minimum angle and a maximum angle, while at the same time the motor pivots synchronously between a maximum pivot angle and a minimum pivot angle. The pump is designed to deliver a volume flow in only one direction. A mechanical range transmission with a plurality of shift steps that can be engaged by means of a clutch is connected downstream. 
         [0004]    Furthermore, from DE 19 52 966 A a transmission device with power branching is known, which comprises a variator, a double planetary gearset and a manual transmission unit for producing a plurality of driving ranges. The pumps and motor unit of the variator made as a hydrostatic device can be adjusted by means of a common yoke. 
       SUMMARY OF THE INVENTION 
       [0005]    The purpose of the present invention is to develop further the transmission devices known from the prior art in such manner that they can also be fitted into vehicles in which lateral space is restricted by a predefined frame structure and fitting space is also restricted upward by the superstructure of the vehicle and downward by a desired ground clearance, without having to redesign existing vehicle systems. 
         [0006]    In the transmission device according to the invention for a vehicle, comprising a variator, a planetary gear unit and a manual transmission unit, such that the variator is longer than it is wide and deep, the longitudinal extension of the variator in its fitted position in the vehicle is orientated at least approximately diagonally. 
         [0007]    In this way the transmission device according to the invention can be fitted into the structural space available in a vehicle in which lateral space is restricted by a defined frame structure and the upward and downward spaces are restricted by the vehicle superstructure and/or by a desired ground clearance, without having to modify the design of existing vehicle systems. 
         [0008]    In an advantageous further development of the transmission device according to the invention, the variator is arranged at least partially below an oil level of the oil sump, in order to enable the variator to be dismantled in a particularly simple manner from the underside of the vehicle. In order to avoid power losses due to oil splashing on the rotating components of the variator during the operation of the transmission device according to the invention, the area of the variator below the oil level is shielded from the hydraulic fluid in the oil sump by partitioning elements. 
         [0009]    Alternatively, in an advantageous embodiment of the transmission device according to the invention the variator is arranged above the oil level in the oil sump, to avoid splashing losses. 
         [0010]    A further embodiment of the transmission device according to the invention is made with a variator designed as a hydrostatic device, in order to be able to transmit as much power as possible, by means of a transmission device that takes up little structural space, from a drive machine of a vehicle, through the transmission device, to a drive output of the vehicle. 
         [0011]    An inexpensive further development of the transmission device according to the invention, which is characterized by a simple structure, is designed with a hydrostatic device comprising at least one constant unit. 
         [0012]    In a further embodiment of the transmission device according to the invention in which the hydrostatic device comprises at least one adjustable pump device and at least one adjustable motor device which can be adjusted independently of one another, the gear ratio ranges produced by means of the variator, the planetary gear unit and the manual transmission unit, whose gear ratio is continuously variable, can be obtained with a large spread. 
         [0013]    In an embodiment of the transmission device according to the invention alternative to the above, the hydrostatic device comprises at least one adjustable pump device and at least one motor device which can be adjusted together. In this way, compared with the previously mentioned embodiment of the transmission device according to the invention, the adjustment of the hydrostatic device is of simple design and can be produced less expensively. 
         [0014]    In an advantageous further development of the transmission device according to the invention, in a simple manner and in relation to the planetary gear unit and the manual transmission unit the variator can be located in any desired position, since in the area of a first shaft and in the area of a second shaft the variator is connected by an angle drive in each case to a shaft of the planetary gear unit. In addition, the connection of the variator by means of angle drives has the advantage that the variator can be actively connected to the planetary gear unit and the manual transmission unit with smaller gearwheels than if the variator were connected by spur gearing. 
         [0015]    In an advantageous further development of the transmission device according to the invention, in its fitted position the variator is arranged between a drive machine of the vehicle and the planetary gear unit and manual transmission unit. In a simple manner, this allows the variator to be removed from a vehicle by pulling it out in the forward direction if the transmission housing is not accessible from the side. Furthermore, if there is appropriate accessibility the variator can also be simply removed from underneath the vehicle with no additional dismantling of vehicle components or tilting of a vehicle cabin. 
         [0016]    With designs of the transmission device having little structural fitting space in the radial direction, either the variator is arranged between the planetary gearset and the manual transmission unit, or the manual transmission unit is arranged between the planetary gearset and the variator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Further advantages and advantageous additional developments of the invention emerge from the claims and from the example embodiments whose principle is described with reference to the drawing; for the sake of clarity, in the description of the example embodiments the same indexes are used for structurally and functionally equivalent components. 
           [0018]    The drawings show: 
           [0019]      FIG. 1 : Gearing layout of a first example embodiment of the transmission device according to the invention; 
           [0020]      FIG. 2 : Schematic three-dimensional side view of the transmission device according to  FIG. 1 ; 
           [0021]      FIG. 3 : Gearing layout of a second example embodiment of the transmission device according to the invention; 
           [0022]      FIG. 4 : Gearing layout of a third example embodiment of the transmission device according to the invention; and 
           [0023]      FIG. 5 : Gearing layout of a fourth example embodiment of the transmission device according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]      FIG. 1  shows a gearing layout of a transmission device  1  with continuously variable gear ratio adjustment, which can be used for example in agricultural vehicles. In this case the transmission device  1  can produce three gear ratio ranges or driving ranges for forward driving and one gear ratio range for reverse drive, within which the gear ratio of the transmission device  1  is continuously adjustable. 
         [0025]    The continuous adjustment of the transmission gear ratio is enabled by a continuous drive unit  2  comprising a variator  3  and a planetary gear unit  4 . By means of the planetary gear unit  4 , the continuous speed adjustability of the variator  3  is superposed on the speed, itself only adjustable to a limited extent, of a transmission input shaft  5  coupled to a drive machine of a vehicle. As a result of this superposition, in the area of the planetary gear unit  4  two shafts  6 ,  7  of the planetary gear unit  4  whose speed is continuously variable are available, the first shaft  6  being in the form of a planetary carrier of the planetary gear unit  4  and being coupled to an adjustable pump unit  3 A of the variator  3 . The second shaft  7  is a sun gear of the planetary gear unit  4  which is in active connection via spur gearing  8  with an adjustable motor unit  3 B of the variator  3 . The pump unit  3 A and the motor unit  3 B of the variator  3  designed as a hydrostatic device are in each case configured with an oblique axis and can be pivoted in the area of a pivot axis  11  by means of a common yoke  12 . 
         [0026]    The continuous drive unit  2  is coupled to a manual transmission unit  9  whose design depends on the power of the variator  3  and also on the design of the planetary gear unit  4 . By means of the manual transmission unit  9  power is transferred from the continuous drive unit  2  toward a transmission output shaft  10 . Furthermore, in the area of the manual transmission unit  9  the required drive output speeds in the various gear ratio ranges are obtained. 
         [0027]    The manual transmission unit  9  is designed with four frictional shift elements S 1  to S 4 , such that when the first shift element S 1  is engaged, the driving range for reverse drive is engaged in the transmission device  1 . The shift elements S 2  to S 4  are provided to produce the three driving ranges for forward drive. 
         [0028]    A second sun gear  13  of the planetary gear unit  4  is connected to the transmission input shaft  5 . Thus, the variator shafts  14  and  15  are respectively coupled to shafts  6 ,  7  of the planetary gear unit  4 , which have no direct connection to the transmission input shaft  5 . Moreover, the variator shafts  14  and  15  are arranged axis-parallel to the shafts  6 ,  7  of the planetary gear unit  4 . 
         [0029]    The variator  3  is designed longer than it is wide and deep, and in its fitted position shown in  FIG. 2  is arranged at least approximately diagonally in a vehicle frame  17 . In this way the structural fitting space available, which is laterally restricted by the structure of the vehicle frame  17  and is also restricted upward in the direction of a vertical vehicle axis  16  and downward by the body structure of the vehicle and by a desired ground clearance, is used to the fullest extent for the fitting of the variator  3  and the transmission device  1 . 
         [0030]    Furthermore, the variator  3  is positioned ahead of the planetary gear unit  4  and the manual transmission unit  9 , as viewed in the forward driving direction of the vehicle indicated by the arrow X in  FIG. 2 . The transmission device  1  is characterized on the one hand by restricted need for structural fitting space in the radial direction and on the other hand by greater axial length. Moreover, owing to its arrangement at the front in the forward driving direction X the variator  3  can be dismantled simply, so that depending on the design in each case, the variator  3  can be removed forward, or in relation to the top of the vehicle downward, or in the direction of the vehicle&#39;s vertical axis  16  upward out of the vehicle frame  17  which, besides other vehicle components, restricts the structural fitting space available in the vehicle for the transmission device  1 . 
         [0031]    If, as in the present case, the variator  3  is arranged at least partially below an oil level  18  in the transmission device  1 , the variator  3  must be shielded by suitable partitioning elements from the hydraulic fluid present in an oil sump (not shown) of the transmission device  1 , in order to avoid in a simple manner so-termed splashing losses during the operation of the transmission device  1  and consequent deterioration of the overall efficiency of the transmission device  1 . 
         [0032]      FIG. 3  shows a gearing layout of a second example embodiment of the transmission device  1 , in which the two variator shafts  14  and  15  are respectively connected by so-termed angle drives  19  and  20  to the shafts  6  and  7  of the planetary gear unit  4 , the angle drives  19 ,  20  being formed in each case by bevel gears or bevel gearing which mesh with one another. The variator shafts  14  and  15  are arranged perpendicularly to the shafts  6  and  7  of the planetary gear unit  4 . In a simple manner, the connection of the variator  3  to the planetary gear unit  4  via the two angle drives  19  and  20  provides the possibility of arranging the variator  3  in the spatial positions shown in  FIGS. 4 and 5 . 
         [0033]    Compared with the first example embodiment shown in  FIGS. 1 and 2 , in which the variator  3  is connected to the shafts  6 ,  7  of the planetary gear unit  4  by spur gearing, the second example embodiment of the transmission device  1  takes up less axial fitting space. In addition, for dismantling purposes the variator  3  can be pulled with little effort, laterally out of a plug connection and away from the bevel gearing of the angle drives  19  and  20 , without having to previously dismantle other vehicle components. 
         [0034]    Depending on the application in each case, it is however also possible to connect the variator in the arrangement shown in  FIGS. 1 and 2  by means of angle drives to the planetary gear unit. 
         [0035]    If insufficient fitting space is available for the variator  3  in the area of the transmission input, the variator  3  can be arranged, in the manner shown in  FIG. 4 , spatially between the planetary gear unit  4  and the manual transmission unit  9  with a diagonal orientation, or in the manner shown in  FIG. 5 , spatially behind the manual transmission unit  9  as viewed in the forward driving direction X so that the manual transmission unit  9  is positioned between the planetary gear unit  4  and the variator  3  and, in relation to a front axle of the vehicle, the transmission device  1  will then take up somewhat more radial fitting space in an area farther to the rear. 
         [0036]    Fundamentally, instead of a variator in the form of a hydrostatic device the power-branched transmission device can also be made with other suitable variators, such as a belt-type variator, a friction wheel variator or the like, in order to be able to vary the gear ratio of the transmission device continuously and in an operating-condition-dependent manner to the desired extent. 
       Indexes 
       [0037]      1  Transmission unit 
         [0038]      2  Continuously variable drive input 
         [0039]      3  Variator 
         [0040]      3 A Pump device 
         [0041]      3 B Motor device 
         [0042]      4  Planetary gear unit 
         [0043]      5  Transmission input shaft 
         [0044]      6  Shaft, planetary carrier 
         [0045]      7  Shaft, solar gear 
         [0046]      8  Spur gearing 
         [0047]      9  Manual transmission unit 
         [0048]      10  Transmission output shaft 
         [0049]      11  Pivot axis 
         [0050]      12  Yoke 
         [0051]      13  Second solar gear 
         [0052]      14 ,  15  Variator shaft 
         [0053]      16  Vertical axis of vehicle 
         [0054]      17  Vehicle frame 
         [0055]      18  Oil level 
         [0056]      19 ,  20  Angle drive 
         [0057]    S 1  to S 4  Shift element 
         [0058]    X Forward driving direction