Abstract:
The invention relates to a gearbox device, in particular, for a hammer drill or chisel, with a torque transmission mechanism, which has a first torque transmitting region for transmission of a torque to a first component and at least one second torque transmitting region for transmitting a torque to a second component. According to the invention, the first torque transmitting region and the second torque transmitting region at least partly have a corresponding partial contour for transmitting the torques.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of U.S. application Ser. No. 12/528,611, which was the National Stage of International Application PCT/EP2008/051014, filed on Jan. 29, 2008. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention is based on a transmission device. 
         [0004]    2. Description of the Prior Art 
         [0005]    A transmission device is already known that has a torque transmission mechanism. The torque transmission mechanism includes a first torque transmission region for transmitting a torque with a first component and at least a second torque transmission region for transmitting a torque with a second component. 
       ADVANTAGES AND SUMMARY OF THE INVENTION 
       [0006]    The invention is based on a transmission device, in particular for a rotary and/or chisel hammer, having a torque transmission mechanism, which has a first torque transmission region for transmitting a torque with a first component and at least one second torque transmission region for transmitting a torque with a second component. 
         [0007]    It is proposed that the first torque transmission region and the second torque transmission region at least partially have a matching contour for transmitting the torques. In this connection, an “at least partially matching contour” should be understood to mean that the contours in at least one partial region have contour lines that coincide, and in particular have coinciding flank contour lines. As a result, the torque transmission mechanism can be produced especially economically and in a simple production process. The torque transmission mechanism, or the contour of the torque transmission mechanism, can be produced by way of punching, milling, pressing, and so forth. The transmission device of the invention can be used especially advantageously in conjunction with a rotary and/or chisel hammer, because of the different gear stages to be attained. In principle, however, the transmission device can be used with other power tools that appear useful to one skilled in the art as well, in particular hand-held power tools. 
         [0008]    If the first torque transmission region and the second torque transmission region are disposed on a radially outward-oriented surface of the torque transmission mechanism, then the torque transmission mechanism can be supported especially advantageously inside the transmission device on a shaft, in particular rotatably on the shaft, for instance on an intermediate shaft of a rotary and/or chisel hammer. 
         [0009]    It is also proposed that the first torque transmission region and the second torque transmission region have an identical cross-sectional face shape, as a result of which the two torque transmission regions can be formed or produced especially economically by means of one work step. 
         [0010]    If the torque transmission mechanism has a continuous contour in the axial direction, then at least an enlarged torque transmission region can be attained, which by itself, or after a relative displacement of the torque transmission mechanism with regard to a component provided for transmitting torque, makes torque transmission with this component possible. 
         [0011]    An especially advantageous spatial adaptation to various components for transmitting a torque can be attained if the first torque transmission region has a lesser addendum circle radius than an addendum circle radius of the second torque transmission region, with an identical root circle radius. Accordingly, an addendum circle diameter of the first torque transmission region is less than an addendum circle diameter of the second torque transmission region. 
         [0012]    In an advantageous refinement of the invention, it is provided that the torque transmission mechanism has at least one partial region, which is located between the first torque transmission region and the second torque transmission region. As a result, the individual torque transmission regions can be restricted in at least one direction, so that by means of a displacement of the torque transmission mechanism relative to a component intended for a torque transmission, a torque transmission can be interrupted in a structurally simple way. 
         [0013]    It is furthermore proposed that the partial region has a contour that differs from the first torque transmission region and from the second torque transmission region, as a result of which additional space can be created for at least one further component and/or at least one further function, such as a switch mechanism and/or a component provided for locking a chisel. Preferably, the partial region has a contour that is embodied in sleevelike fashion, and a radially outward-oriented surface of the partial region, at every point, has an identical spacing, in each case the shortest spacing, relative to a center axis of the torque transmission mechanism. 
         [0014]    If the partial region has a radius that is reduced compared to the first torque transmission region and to the second torque transmission region, then the partial region can be produced especially economically by means of simply being twisted off. 
         [0015]    In a further feature of the invention, it is proposed that the transmission device has the first component, which is formed by a sleeve and by means of which component a torque can be transmitted to the torque transmission mechanism, as a result of which a large transmission area between the first component and the torque transmission mechanism can be attained. Moreover, structurally simple switching of the torque transmission can advantageously be attained by means of an axial displacement of the sleeve. 
         [0016]    It is furthermore proposed that the transmission device has the second component, which is formed by a gear wheel that is disposed in a manner fixed against relative rotation on a hammer barrel; as a result, direct transmission of a torque to a power takeoff mechanism can advantageously be attained with fewer additional components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of a preferred embodiment taken in conjunction with the drawings, in which: 
           [0018]      FIG. 1  shows a hand-held power tool having a transmission device according to the invention; 
           [0019]      FIG. 2  shows the transmission device in a three-dimensional sectional view; 
           [0020]      FIG. 3  shows a torque transmission mechanism from  FIG. 2  in a three-dimensional sectional view; and 
           [0021]      FIG. 4  shows an alternative torque transmission mechanism in a three-dimensional sectional view. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    In  FIG. 1 , a hand-held power tool  46  formed by a rotary hammer is shown. The hand-held power tool  46  includes a housing  48  and a tool holder  50 , in a front region, for receiving a tool. On a side facing away from the front region, the hand-held power tool  46  has a main handle  52  for actuating the hand-held power tool  46  and transmitting force from a user to the hand-held power tool  46 . 
         [0023]    For generating a driving torque, the hand-held power tool  46  has a drive unit  54 , formed by an electric motor. The driving torque of the drive unit  54  is transmitted via a transmission device  10  of the hand-held power tool  46  to an impact mechanism  56 , which for the sake of simplicity is shown only partially in  FIG. 2 , and/or to a rotating power takeoff mechanism  58  formed by a hammer barrel  44  ( FIG. 2 ). 
         [0024]    The transmission device  10  includes an intermediate shaft  60  and a torque transmission mechanism  12  supported on the intermediate shaft  60  ( FIG. 2 ). The torque transmission mechanism  12  has a first torque transmission region  14  and a second torque transmission region  18  for transmitting a torque with a first component  16  and a second component  20 , respectively ( FIGS. 2 and 3 ). The two torque transmission regions  14 ,  18  are disposed on a radially outward-oriented surface  24  of the torque transmission mechanism  12 . The first torque transmission region  14  is disposed in an axial direction  28  of the torque transmission mechanism  12  on a drive-side end region  62  of the torque transmission mechanism  12 , and the second torque transmission region  18  is disposed on an end region  64  of the power takeoff side of the torque transmission mechanism  12 . The two torque transmission regions  14 ,  18  furthermore have a matching contour  22  for transmitting the respective torque, and the first torque transmission region  14  has a lesser addendum circle radius  30  than an addendum circle radius  82  of the second torque transmission region  18 , for the same root circle radius  32  ( FIG. 3 ). 
         [0025]    Between the first torque transmission region  14  and the second torque transmission region  18 , there is a further partial region  34  of the torque transmission mechanism  12 , and this partial region is embodied in sleevelike fashion and has a smooth contour  36  without toothing. A radius  38  of the partial region  34  is shorter than&#39;a root circle radius  32  of the first torque transmission region  14  and of the second torque transmission region  18  ( FIGS. 2 and 3 ). 
         [0026]    In operation of the transmission device  10  of the hand-held power tool  46 , the torque transmission mechanism  12  can transmit torque from the intermediate shaft  60  to the hammer barrel  44 . For that purpose, the intermediate shaft  60  is press-fitted onto a drive gearing  66  in a manner fixed against relative rotation. Along a force flow direction  68 , the torque transmission mechanism  12  is disposed downstream of the drive gearing  66  on the intermediate shaft  60 . Downstream of the torque transmission mechanism  12  in turn in the force flow direction  68 , a spring  70  is disposed in prestressed fashion on the intermediate shaft  60 . Because of a spring force of the spring  70 , the torque transmission mechanism  12  is braced against the drive gearing  66  of the intermediate shaft  60  ( FIG. 2 ). 
         [0027]    To transmit torque from the intermediate shaft  60  or the drive gearing  66  of the intermediate shaft  60  to the torque transmission mechanism  12 , a first component  16 , which is formed by a sleeve  40 , is supported displaceably in the axial direction  28  on the torque transmission mechanism  12 . The sleeve  40  has an inner contour, not identified by reference numeral, that corresponds to the first torque transmission region  14 , and on a drive-side end region  72 , it has an inner contour corresponding to the drive gearing  66 . By means of a switch mechanism  74 , which is formed by a switch plate, the sleeve  40  is displaceable in the axial direction  28  on the torque transmission mechanism  12 , so that in operation of the hand-held power tool  46 , torque transmission from the intermediate shaft  60  to the hammer barrel  44  via the torque transmission mechanism  12  can be switched on and off by a user. In  FIG. 2 , a drive-side end position of the sleeve  40  is shown, which in operation of the hand-held power tool  46  enables a transmission of the driving torque from the intermediate shaft  60  to the torque transmission mechanism  12 , via the drive gearing  66  and the sleeve  40 . If the sleeve  40  is pushed by the switch mechanism  74  in the direction of the second torque transmission region  18 , the inner toothing of the sleeve  40 , corresponding to the drive gearing  66 , is pushed out of the operative range of the drive gearing  66 , and torque transmission between the intermediate shaft  60  and the torque transmission mechanism  12 , or the drive gearing  66  and the sleeve  40 , is interrupted. 
         [0028]    The second torque transmission region  18  of the torque transmission mechanism  12  is provided for transmitting torque to the hammer barrel  44 , in operation of the hand-held power tool  46 . To that end, a second component  20 , which is formed by a gear wheel  42 , is disposed on the hammer barrel  44  in a manner fixed against relative rotation. This gear wheel  42  has a transmission contour  76  corresponding to the second torque transmission region  18 . If the sleeve  40  is in the drive-side end position, then in operation of the hand-held power tool  46 , the torque of the intermediate shaft  60  is transmitted to the torque transmission mechanism  12  via the drive gearing  66  and the sleeve  40  and from the torque transmission mechanism  12  to the hammer barrel  44  via the gear wheel ( FIG. 2 ). 
         [0029]    If in operation of the hand-held power tool  46  the sleeve  40  is in a position on the power takeoff side, torque transmission by means of the sleeve  40  to the torque transmission mechanism  12  is interrupted, and by means of the switch plate or a partial region  78 , on the power takeoff side, of the switch plate, chisel locking is achieved. To that end, the partial region  78 , on the power takeoff side, of the switch plate has a contour  80  corresponding to the second torque transmission region  18 , which contour, in the position of the power takeoff side, meshes with the second torque transmission region  18  and thus prevents rotation of the torque transmission mechanism  12 , hammer barrel  44 , or a tool connected in a manner fixed against relative rotation to the hammer barrel  44 . If the sleeve  40  is in the drive-side end position, a rotation of the torque transmission mechanism  12  relative to the partial region  78 , on the power takeoff side, of the switch plate in operation of the hand-held power tool  46  is possible, because of the slight radius  38  of the partial region  34  of the torque transmission mechanism  12  compared to the second torque transmission region  18 , so that locking between the partial region  34  and the switch plate is undone. 
         [0030]    In  FIG. 4 , a torque transmission mechanism  12  of a transmission device  10  is shown that is an alternative to  FIGS. 2 and 3 . The description of this exemplary embodiment will be limited to differences from the exemplary embodiment shown in  FIGS. 2 and 3 . For characteristics that remain the same, the description of the exemplary embodiment in  FIGS. 2 and 3  may be referred to. 
         [0031]    Analogous characteristics of the various exemplary embodiments are identified by the same reference numerals. 
         [0032]    A first torque transmission region  14  has an identical cross-sectional face shape  26  to a second torque transmission region  18  of the torque transmission mechanism  12 . In addition, the torque transmission mechanism  12  has a continuous contour  22  with an addendum circle radius  30  that remains constant and a root circle radius  32  that remains constant ( FIG. 4 ). 
         [0033]    The foregoing relates to the preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.