Abstract:
A camshaft adjuster for motor vehicles has an oscillating motor having a rotor that is fixedly connected to a camshaft and further having a stator surrounding the rotor. The rotor is rotatable relative to the stator. At least one connecting part acting by at least one of positive engagement and force transmission is provided on a camshaft having cams. The rotor has a base member that is fixedly mounted on the connecting part. The base member has a diameter that is different from a diameter of a circle circumscribing the cams of the camshaft.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a camshaft adjuster for vehicles, especially motor vehicles, comprising an oscillating motor having a rotor that is fixedly connected to the camshaft and rotatable relative to a stator surrounding the rotor.  
           [0003]    2. Description of the Related Art  
           [0004]    Camshaft adjusters are known that have an oscillating motor that is connected at the end of a camshaft by means of a central screw. By hydraulically loading the rotor of the oscillating motor, a rotatory movement relative to the stator results and, in this way, an adjustment of the camshaft relative to the crankshaft is achieved. The supply of hydraulic medium is realized either directly through the camshaft or by means of a rotary lead-through in the oscillating motor. It is also known to fasten the rotary lead-through behind the oscillating motor by means of the central screw on the camshaft. The camshaft adjuster has a complex configuration and requires a correspondingly complex assembly.  
         SUMMARY OF INVENTION  
         [0005]    It is an object of the present invention to configure the camshaft adjuster of the aforementioned kind such that, while providing a simple configuration, an inexpensive assembly is ensured without this negatively affecting the proper function of the camshaft adjuster.  
           [0006]    In accordance with the present invention, this is achieved in that the camshaft comprises at least one connecting part that acts by positive-engagement and/or force transmission and on which the base member of the rotor is fixedly mounted, wherein the base member has a diameter that is different than the diameter of the circle circumscribing the cams of the camshaft.  
           [0007]    In the camshaft adjuster according to the invention, the rotor is fixedly connected by means of a positive-engagement and/or force transmission part to the camshaft. Because of the configuration according to the invention, the camshaft adjuster has only a minimal number of components, and this leads to a simple and inexpensive assembly.  
           [0008]    Advantageously, the inner diameter of the base member of the rotor is greater than the diameter of the circle that circumscribes the cams of the camshaft. Accordingly, the oscillating motor can be pushed axially across the cams onto the positive-engagement and/or force transmission part. The camshaft requires therefore only two bearing locations. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0009]    [0009]FIG. 1 is a perspective illustration, partially in section, of a camshaft adjuster according to the invention.  
         [0010]    [0010]FIG. 2 is a perspective illustration of a camshaft of the camshaft adjuster according to FIG. 1 provided with a positive-engagement part for receiving a rotor of the camshaft adjuster.  
         [0011]    [0011]FIG. 3 is a second embodiment of a camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0012]    [0012]FIG. 4 shows the second embodiment of FIG. 3 in an illustration similar to FIG. 2.  
         [0013]    [0013]FIG. 5 shows a third embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0014]    [0014]FIG. 6 shows the third embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0015]    [0015]FIG. 7 shows a fourth embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0016]    [0016]FIG. 8 shows the fourth embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0017]    [0017]FIG. 9 shows a fifth embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0018]    [0018]FIG. 10 shows the fifth embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0019]    [0019]FIG. 11 shows a sixth embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0020]    [0020]FIG. 12 shows the sixth embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0021]    [0021]FIG. 13 shows a seventh embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0022]    [0022]FIG. 14 shows the seventh embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0023]    [0023]FIG. 15 shows an eighth embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0024]    [0024]FIG. 16 shows the eighth embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0025]    [0025]FIG. 17 shows a ninth embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0026]    [0026]FIG. 18 shows the ninth embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0027]    [0027]FIG. 19 shows a tenth embodiment of the camshaft adjuster according to the invention in an illustration similar to FIG. 1.  
         [0028]    [0028]FIG. 20 shows the tenth embodiment of the camshaft adjuster in an illustration similar to FIG. 2.  
         [0029]    [0029]FIG. 21 shows in axial section of a camshaft embodied as a hollow shaft with an insert. 
     
    
     DETAILED DESCRIPTION  
       [0030]    The camshaft adjuster according to FIGS. 1 and 2 has an oscillating motor  1  comprising a stator  2  and a rotor  3 . The stator  2  has a cylindrical outer wall  4  and webs  5  projecting radially inwardly from the wall  4  at a uniform spacing to one another. The rotor  3  is mounted fixedly on the camshaft  6  and has an annular base member  7  that is fastened fixedly on the camshaft  6 . Web-shaped vanes  8  project from the base member  7  radially outwardly and are spaced at a uniform spacing to one another. The end faces  9  of the vanes  8  rest areally on the inner side  10  of the outer wall  4  of the stator  2 . The stator webs  5  rest with their end faces  11  areally on the cylindrical outer side  12  of the base member  7  of the rotor  3 . The spacing of neighboring stator webs  5  from one another is greater than the width of the rotor vanes  8 . The stator webs  5  delimit pressure chambers  13  that are divided by the rotor vanes  8  into two pressure chambers  14  and  15 . A pressure medium can be introduced into the pressure chambers  14 ,  15  in a way known in the art so that the rotor vanes  8  can be pressure-loaded alternatingly on one or the other side. Accordingly, the rotor  3  is rotated relative to the stator  2 . The maximum rotational travel of the rotor  3  relative to the stator  2  is achieved when the rotor vanes  8  rest against the stator webs  5 .  
         [0031]    On the radial outer ends of the sidewalls  16 ,  17  of each stator web  5 , a recess in the form of a groove  18 ,  19  is provided that extends across the axial width of the stator webs  5 . In the grooves  18 ,  19 , dirt particles, for example, are collected that are contained within the pressure medium. Moreover, the pressure medium that is contained in the grooves  18 ,  19  provides a damping action when the rotor vanes  8  come to rest against the sidewalls  16 ,  17  of the stator webs  5 . The stator webs  5  can have very different shapes. For example, the sidewalls  16 ,  17  of the stator webs  5  can be plane. The sidewalls  16 , 17  can also have a different course. For example, the cross-sectional width of the stator webs  5  can taper irregularly radially inwardly. The stator  2  itself is provided, as is known in the art, with a chain wheel or pulley  25  across which a chain or belt is guided that is, in turn, guided across a chain wheel or pulley that is mounted on the crankshaft.  
         [0032]    The camshaft  6  has a positive-engagement connecting part  20  that has a non-round cross-section. In the illustrated embodiment of FIGS. 1 and 2, the positive-engagement connecting part  20  has a pentagon-shaped cross-section wherein the circumferential surfaces  21  of the positive-engagement connecting part  20  have a rounded transition into one another. The base member  7  of the rotor has an inner wall  22  whose contour is matched to the contour of the positive-engagement connecting part  20 . The rotor  3  is pushed onto the positive-engagement connecting part  20  wherein as a result of the non-round cross-section a proper fixed connection between the rotor  3  and the camshaft  6  is achieved so that the parts cannot rotate relative to one another.  
         [0033]    The cams that are arranged on the camshaft  6  are positioned, as is known in the art, angularly displaced relative to one another. The circumcircle of the cam profiles is smaller than the smallest diameter of the positive-engagement connecting part  20 . In this way, it is possible to push the rotor  3  across the cams of the camshaft  6  onto the positive-engagement connecting part  20 . In this way, a central drive is enabled in a simple way. By means of the positive-engagement connecting part  20 , the supply of the pressure medium that is to be introduced into the pressure chambers  14 ,  15  of the oscillating motor  1  can be realized. The corresponding bores in the positive-engagement connecting part  20  for supplying the pressure medium are not illustrated in FIGS. 1 and 2. In place of such bores, it is also possible to provide annular grooves on the positive-engagement connecting part  20 .  
         [0034]    The rotor  3  is fastened with its base member  7  in a suitable way on the positive-engagement connecting part  20 , preferably by press-fit. A cylindrical collar  23  adjoins the positive-engagement connecting part  20 . The collar  23  projects radially past the positive-engagement connecting part  20  and serves as an abutment or axial stop for the base member  7  of the rotor  3 . By means of this collar  23 , the rotor  3  can moved into its mounting position in a simple way during mounting.  
         [0035]    As illustrated in FIG. 1, the base member  7  of the rotor has an axial annular projection  24  with which the base member  7  rest against the collar  23  of the camshaft  6 . On this projection  24  a chain wheel  25  is supported that is fixedly connected to the stator  2 . The chain wheel or pulley  25  can also be formed as a monolithic part of the stator  2 . The chain wheel or pulley  25  closes off the pressure chambers  14 ,  15  in the axial direction. On the opposite side, a cover plate (not illustrated) is provided that is fastened on the stator  2  and closes off the pressure chambers axially on the other side.  
         [0036]    In the embodiment according to FIGS. 3 and 4, the camshaft  6  is extended axially past the positive-engagement connecting part  20 . On the projecting cylindrical part  26  of the camshaft  6 , an axial securing element  27  is secured by press-fit whose outer diameter is greater than the greatest outer diameter of the positive-engagement part  20 . The axial securing element  27  is formed as an annular disk and has on its circumference four grooves  24  that are spaced at an angular spacing of 90E relative to one another and serve as positive-engagement openings for a tool with which the axial securing element  27  can be placed onto the camshaft part  26 . As described in the preceding embodiment, the rotor  3  is moved across the cams of the camshaft  6  onto the positive-engagement connecting part  20  and is secured thereon by press-fit. The part  26  projects past the rotor  3  in the axial direction. The axial securing element  27  is fastened on the part  26 . For example, it can be pressed onto this projecting part  26 . It is also possible to provide the projecting part  26  with a thread so that the axial securing element  27  is screwed onto the part  26 . In the mounted position, the axial securing element rests against the cover plate (not illustrated) that is pushed by the axial securing element  27  against the stator  2 .  
         [0037]    The oscillating motor  1  is in other respects of the same configuration as in the preceding embodiment.  
         [0038]    In the embodiment according to FIGS. 5 and 6, the axial securing element  27  is formed by a spring ring or securing ring that is inserted into an annular groove  29  near the free end of the projecting part  26  of the camshaft  6 .  
         [0039]    In the mounted position, the part  26  of the camshaft  6  projects past the cover plate (not illustrated) of the oscillating motor. Into the annular groove  29  a spring ring or securing ring  27  is inserted so that the oscillating motor  1  is properly axially secured on the positive-engagement connecting part  20  of the camshaft  6 .  
         [0040]    In the oscillating motor according to FIGS. 7 and 8, a spring ring or securing ring is used as the axial securing element  27  that is provided in the annular groove  29  near the free end of the axially projecting end of the camshaft  6 .  
         [0041]    The positive-engagement connecting part  20 , in contrast to the preceding embodiment, is substantially cylindrical. The positive-engagement connecting part  20  has on its outer wall  30  at least one positive-engagement element  31  that is formed as a projection on the outer wall  30 . This positive-engagement element  31  has a substantially rectangular contour and extends from the collar  23  in the direction toward the annular groove  29 . As illustrated in FIG. 8, the axially extending positive-engagement element  31  has a sufficient spacing from the annular groove  29  so that, when mounting the oscillating motor  1 , the spring ring or securing ring  27  can be inserted simply into the annular groove  29 .  
         [0042]    The inner wall  22  of the base member  7  of the rotor  3  has for receiving the positive locking element  31  a matching groove-shaped depression  32  that is engaged positively by the positive-engagement element  31 . By means of this positive-engagement connection  31 ,  32 , the rotor  3  is connected fixedly to the camshaft  6 . Since the rotor  3  is not secured by press-fit on the positive-engagement connecting part  20 , a problem-free mounting of the rotor  3  is ensured. It can be easily pushed onto the positive-engagement connecting part  20 . The axial securing action is realized by the spring ring or securing ring  27  that can be inserted without problems into the annular groove  29  of the camshaft part  26 .  
         [0043]    On the outer wall  30  of the positive-engagement connecting part  20  additional positive-engagement elements  31  can be provided should this be necessary.  
         [0044]    [0044]FIGS. 9 and 10 show an oscillating motor where the annular projection  24  of the base member  7  of the rotor has an inner wall  33  with a non-round cross-section. The rotor is seated with this projection  24  on the positive-engagement element  20  of the camshaft  6 . In contrast to the preceding embodiments, the positive-engagement connecting part  20  is formed as a collar that has only minimal axial width. The positive-engagement connecting part  20  has the same contour as the positive-engagement connecting part  20  of the preceding embodiment. The positive-engagement connecting part  20  adjoins directly the collar  23  that projects radially past the positive-engagement connecting part  20 . The part  26  that is positioned on the other end of the positive-engagement connecting part  20  is cylindrical and has at its free end an annular groove  29  that receives the spring ring or securing ring  27  as an axial securing element.  
         [0045]    In this configuration, the rotor  3  can also be pushed across the cams of the camshaft  6  to such an extent that it engages with its projection  24  the positive-engagement connecting part  20 . In this way, the rotor  3  is connected in a simple way fixedly to the camshaft  6 . The camshaft projects with its part  26  so far axially past the rotor  3  or the cover plate (not illustrated) that the spring ring or safety ring  27  can be inserted into the annular groove  29 .  
         [0046]    The rotor  3  is then properly secured axially on the camshaft  6 . In other respects, the oscillating motor  1  is of the same configuration as in the preceding embodiments.  
         [0047]    [0047]FIGS. 11 and 12 show an oscillating motor  1  whose rotor  3  is pushed onto the positive-engagement connecting part  20  of the camshaft  6 . The positive-engagement connecting part  20  is identical to the embodiment of FIGS. 1 and 2. As a result of the non-round cross-section of this positive-engagement connecting part  20 , the rotor  3  is fixedly fastened on the camshaft  6 . For axially securing the rotor  3  or the oscillating motor  1  on the camshaft  6 , the axial securing element  27  as well as a groove nut  24  are provided. The axial securing element  27  in this embodiment is a securing disk that rests against the end face of the cover plate (not illustrated) and is secured by means of the groove nut  34 . It is screwed onto a tapered threaded end of the camshaft  6 . The rotor  3  is positioned axially secured between the collar  23  and the annular disk  27 .  
         [0048]    In other respects, the camshaft adjuster is of the same configuration as in the embodiment of FIGS. 1 and 2.  
         [0049]    The camshaft adjuster according to FIGS. 13 and 14 comprises the positive-engagement connecting part  20  with the positive-engagement element  31  in accordance with the embodiment of FIGS. 7 and 8. The camshaft  6  is provided in accordance with the preceding embodiment with a threaded end onto which the groove nut  34  is screwed. By means of the nut, the axial securing element  27  in the form of the annular disk is secured; the annular disk rests against the cover plate (not illustrated) or the rotor  3  of the oscillating motor  1  and axially secures it between the collar  23  and the axial securing element  27  in the mounted position. In other respects, the oscillating motor is identical to the embodiment of FIGS. 11 and 12.  
         [0050]    The camshaft adjuster according to FIGS. 15 and 16 is similarly configured as the embodiment of FIGS. 3 and 4. In accordance with this embodiment, the axial securing element  27  is positioned on the projecting part  26  of the camshaft adjuster  6 . Instead of the positive-engagement connecting part  20 , the camshaft  6  has a cylindrical part  35  on which the rotor  3  is secured with press-fit. The fixed connection between the rotor  3  and the camshaft  6  is realized in this case by force transmission (friction). Onto the free end of the part  26  of the camshaft  6 , the axial securing element  27  is placed in the same way as described in connection with FIGS. 3 and 4. The rotor  3  is thus axially secured between the collar  23  of the camshaft  6  and the axial securing element  27  on the camshaft  6 .  
         [0051]    In the embodiment according to FIGS. 17 and 18, the camshaft  6  has the positive-engagement connecting part  20  with positive-engagement element  31  in accordance with the embodiment of FIGS. 7 and 8. The part  26  that projects axially past the positive-engagement connecting part  20 , in contrast to the embodiment of FIG. 7 and  8 , is not provided with an annular groove  29  but has a continuous cylindrical configuration. On this projecting part  26 , the axial securing element  27  is fastened that is identical to that of the embodiment of FIGS. 3 and 4. The axial securing element  27  in the embodiment of FIGS. 17 and 18 can be attached in the same way as explained in connection with the embodiment of FIGS. 3 and 4. The rotor  3  of the oscillating motor  1  is axially secured between the collar  23  of the camshaft  6  and the axial securing element  27 .  
         [0052]    In the embodiment of FIGS. 19 and 20, the camshaft  6  is provided with an axially projecting force transmission part  36  projecting past the collar  23  and configured to be of a truncated-cone shape. The base member  7  of the rotor  3  of the oscillating motor  1  is fastened on the part  36  by means of press-fit. The inner wall  22  of the rotor base member  7  is positioned on a conical surface.  
         [0053]    Because of the force transmission between the rotor base member  7  and the force transmission part  36  of the camshaft  6 , a proper fixed connection between the rotor  3  and the camshaft  6  is achieved. It is possible without problems to axially secure the rotor  3  by means of an axial securing element on the camshaft  6 . The provided axial securing element  27  can be configured in accordance with the preceding embodiments.  
         [0054]    In the described embodiments, the camshaft  6  requires only two bearing locations. In particular, only a minimal number of components is required because a rotary lead-through for the pressure medium in the oscillating motor  1  is obsolete. The central screw required in the known camshaft adjusters for attachment of the oscillating motor to the camshaft is also no longer needed. The camshaft adjuster according to the described embodiments can therefore be produced simply and inexpensively. The supply of pressure medium into the pressure chambers  14 ,  15  is realized through the camshaft  6 . In this way, radial bores for supply of pressure medium are not necessary. However, when the camshaft  6  is of a hollow configuration, an insert  37  with oil channels must be inserted as illustrated in FIG. 21. The insert  37  rests against the inner wall  38  of the hollow camshaft  6  and has two axially extending bores  39  and  40  through which the pressure medium can be introduced into the pressure chambers  14 ,  15  of the oscillating motor  1 . The two bores  39 ,  40  open into a first end face  41  of the insert  37  and are connected, as is known in the art, to the valve unit with which the supply of pressure medium to the pressure chambers  14 ,  15  is controlled.  
         [0055]    Radial bores  42 ,  43  that are spaced from one another open into the bore  39 ; they are provided at the bottom of an annular groove  44 ,  45  in the wall surface  46  of the insert  37 , respectively.  
         [0056]    The radial bores  47 ,  48  open in the annular groove  44 ,  45  into the camshaft  6 .  
         [0057]    Radial bores  49 ,  50  that are spaced from one another open into the axial bore  40  of the insert  37 ; they are provided at the bottom of two annular grooves  51 ,  52  in the wall surface  46  of the insert  37 , respectively. Radial bores  53 ,  54  of the camshaft  6  open into the annular groove  51 ,  52 .  
         [0058]    When employing a hollow camshaft  6  with the insert  37 , the constructive length can be reduced.  
         [0059]    The axial securing of the oscillating motor  1  is realized in the described embodiments by means of the axial securing element  27  or by means of a press-fit connection.  
         [0060]    In the embodiments in which the positive-engagement connecting part  20  has a polygonal or non-round cross-section (FIGS. 1 through 6,  9  through  12 ), it is advantageous when the number of corners corresponds to the number of rotor vanes  8 . In this way, a uniform stress distribution is ensured in the rotor  3 .  
         [0061]    While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.