Abstract:
An adjustment fitting, in particular for a vehicle seat, includes a first fitting part and a second fitting part that can be rotationally adjusted relative to the first fitting part about an axis of rotation. An external gear, which has internal teeth and into which an internal gear that is associated with the second fitting part and has external teeth is inserted eccentrically to the axis of rotation like an eccentric gear, is associated with the first fitting part. The internal gear forms an eccentric receiving space towards the axis of rotation. The adjustment fitting further comprises an eccentric member that is rotatably inserted into the eccentric receiving space, and a drive shaft for driving the eccentric member. The external gear is designed as a ring gear that has a bottom and an external wall which axially extends beyond the internal teeth and embraces the external teeth of the internal gear by means of a radially inward-oriented collar. In addition, the internal gear comprises an internal wall which axially extends beyond the external teeth and axially penetrates the collar. The fitting parts are thus securely fastened in the axial direction while access is made easy, especially for mounting the adjustment fitting on a vehicle seat or a seat adapter.

Description:
[0001]    This nonprovisional application is a continuation of International Application No. PCT/EP2009/004086, which was filed on Jun. 6, 2009, and which claims priority to German Patent Application Nos. DE 10 2008 028 102.6, which was filed in Germany on Jun. 13, 2008, and to DE 10 2008 028 103.4, which was filed in Germany on Jun. 13, 2008; and which are all herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to an adjustment fitting, in particular for a motor vehicle seat, having a first fitting part, having a second fitting part that is rotationally adjustable relative to the first fitting part about an axis of rotation, wherein the first fitting part has associated with it an outer wheel with internal teeth, in which wheel is inserted eccentrically to the axis of rotation, in the manner of a wobble mechanism, an inner wheel with external teeth that is associated with the second fitting part, and wherein the inner wheel forms a receiving space that is eccentric to the axis of rotation, having an eccentric cam rotatably inserted in the eccentric receiving space, and having a drive shaft for driving the eccentric cam. 
         [0004]    2. Description of the Background Art 
         [0005]    An adjustment fitting of this nature is known, for example, from DE 100 21 403 C2, DE 31 30 315 C2 and DE 28 34 529 C2, which corresponds to U.S. Pat. No. 4,322,112. In these fittings, the first fitting part and the second fitting part are connected in the manner of a wobble mechanism, wherein the inner wheel rolls with its external teeth along the internal teeth of the outer wheel with a wobbling motion when the eccentric cam is driven. The number of teeth in the external teeth is smaller than the number of teeth in the internal teeth. One full rotation of the eccentric cam results in a rotation of the inner wheel relative to the outer wheel by the difference in tooth count. An adjustment fitting with wobble mechanism has become established in the automotive industry for adjusting the backrest relative to the seat base of a motor vehicle seat. A wobble mechanism can be implemented with relatively few mechanical parts, and permits flat construction together with a transmission ratio desirable for adjustment. 
         [0006]    In the final assembled state, the fitting parts, or the inner and outer wheel of such an adjustment fitting, are held together in the axial direction. An extremely wide variety of retaining means are known from the prior art for this purpose. If the axial play between the fitting parts is too great, the result is undesirable rattling noises, which the vehicle occupant may potentially find worrisome, or at the very least perceive as unpleasant. On the other hand, if the axial play between the fitting parts is too small, an unnecessarily high frictional force has to be overcome in order to adjust the fitting. 
         [0007]    Known from the aforementioned DE 100 21 403 C2 for holding the two fitting parts together axially is a retention ring overlapping the two fitting parts that is attached in a rotationally fixed manner to at least one of the fitting parts by means of a polygonal interlock. 
         [0008]    According to DE 10 105 282 B4, which corresponds to U.S. Pat. No. 6,799,806, the fitting parts of an adjustment fitting are held together axially by a retaining ring, wherein a fitting part is pressed into the retaining ring. This is intended to permit easier assembly. It is additionally proposed therein to design the retaining ring with an internal step, with the fitting part being pressed in up to said step. 
         [0009]    From DE 31 30 315 C2, it is known to use a plate washer, which is permanently attached to one fitting part, for axially holding together the two fitting parts of an adjustment fitting. In this solution, the edge of the washer constitutes internal teeth that mesh with overhanging external teeth of the inner wheel. To hold the fitting parts together axially, the plate washer is interlocked with a retaining element that is pressed into slots in the other fitting part and is attached to this fitting part in a position with no play. 
         [0010]    Finally, DE 28 34 529 C2 discloses a bearing plate holding the fitting parts of an adjustment fitting together axially, which has lateral bent portions that laterally overlap the two fitting parts. During assembly, the fitting parts are pressed together with no play, and the outer fitting part is permanently attached to the lateral bent portions in this position. 
       SUMMARY OF THE INVENTION 
       [0011]    It is an object of the invention is to provide an adjustment fitting in which the fitting parts are held together as securely as possible and which permits easy installation in a vehicle seat. 
         [0012]    According thereto, provision is made for the outer wheel to be designed as a ring gear with a floor and with an outer wall that is extended in the axial direction past the internal teeth and that overlaps the external teeth of the inner wheel with a radially inward facing collar, wherein the inner wheel includes an inner wall that is extended in the axial direction past the external teeth and that passes through the collar in the axial direction. 
         [0013]    In this way, the inner wheel is held securely on the outer wheel in the axial direction between the floor and the radially inward facing collar. As a result of the extended inner wall of the inner wheel, easy installation of an adapter is possible for attachment to a specific vehicle seat. The inner wheel is accessible from outside by means of the extended inner wall. An appropriate adapter can be attached by means of welding, for example, advantageously by means of laser welding. Alternatively, the inner wheel can be attached via its inner wall to the second fitting part or to an adapter by means of adhesives or soldering. In this regard, the inner wheel is preferably associated with the second fitting part via the inner wall. In addition, the extended inner wall allows axial displacement of the relevant adapter, which can be made in different thicknesses, up until it is fastened, by which means the number of variants can be reduced. 
         [0014]    In an embodiment of the adjustment fitting, the ring gear can be divided along the internal teeth and is composed of a first and a second shell, wherein the second shell overlaps the external teeth of the inner wheel as a collar. A compact design of the adjustment fitting is made possible in this way. The internal teeth of the inner wheel are held securely between the two shells of the outer wheel. Easy installation is possible as a result of the two-part design. 
         [0015]    In an alternative embodiment, the collar is composed of a retaining element that can be pushed axially in the outer wall toward the inner wheel, which retaining element is attached to the outer wall, wherein the inner wheel is supported against the floor of the ring gear. 
         [0016]    During assembly, the inner wheel is pushed axially into the ring gear until the floor is reached, and the retaining element is then guided into the interior of the ring gear after it, so that the inner wheel is supported between the floor and the retaining element. Because of the axial displaceability of the retaining element, the axial play of the inner wheel with respect to the outer wheel can be adjusted to zero play. Once the desired position of the retaining element relative to the floor of the outer wheel has been reached, the retaining element is secured to the outer wall. In particular, this can be accomplished by means of a suitable welding technique. In advantageous manner, the securing of the retaining element in the outer wheel is accomplished by means of laser welding. This can be done by means of a circumferential fillet weld. In particular, a connection by means of what is called a “square butt weld,” which is produced by laser welding, is present. Naturally, fastening by means of adhesives or soldering is also possible. The joining of the retaining element to the outer wall of the outer wheel can be carried out at discrete points or circumferentially. In other words, the ring gear has internal teeth that are axially recessed relative to the outer wall. Preferably, the ring gear itself is likewise laser welded to the first fitting part. 
         [0017]    In this design, the setting of the desired position of the retaining element relative to the floor of the outer wheel can be controlled either by force or by distance. In the case of a setting controlled by force, manufacturing tolerances in the axial height of the inner wheel are compensated. On the other hand, distance-controlled establishment of the desired position allows for variants having alterable strength through variation of the axial thickness of the inner wheel with otherwise identical components. For example, if the thickness of the inner wheel is increased in the case of distance-controlled establishment of the position of the retaining element, this results in an adjustment fitting with increased strength. 
         [0018]    It is not necessary for the floor to be designed to have complete area coverage. In principle, it is sufficient to design the floor as a support for the inner ring. A suitably designed edge or partial surface is sufficient for this purpose. Preferably, however, the floor essentially closes off the interior space of the ring gear. In this way, the ring gear can simultaneously form an outer boundary of the adjustment fitting. The interior space, and thus the wobble mechanism, is protected from dirt and the like. 
         [0019]    Nor is it necessary to the invention that the axial width of the internal teeth match the axial width of the external teeth. For example, the entire inner wheel can have a reduced thickness as compared to the thickness of the external teeth and can be supported against the floor past the external teeth by means of angled sections of the collar or of the retaining element. In contrast, it is also possible for the external teeth to have an increased axial width as compared to the internal teeth, and for the inner wheel to be supported on the collar by means of the radially projecting external teeth. In this design, it is possible in particular for the external teeth to be located on a sort of flange by means of which the inner wheel is supported against the collar. 
         [0020]    There are in principle no restrictions regarding the outer contour of the outer wall and inner wall. Both the outer and inner walls can be axially extended in a prismatic manner to form respective hypothetical or actual base surfaces. In particular, polygonal circumferential contours are also possible. 
         [0021]    In an embodiment, the outer wall of the ring gear and the inner wall of the inner wheel are each designed as a cylinder wall. The rotationally symmetrical design of the components permits simplified manufacture. In addition, it is not necessary to ensure a specific rotational position of the components relative to one another when joining them. 
         [0022]    The retaining element can be designed as a retaining ring or retaining washer that surrounds the inner wheel or its external teeth at least at the edge. As a result of the rotational symmetry, this results in a secure and stable support of the inner wheel in the outer wheel. 
         [0023]    A central elongated collar can be formed on the floor of the ring gear, so that the eccentric receiving space is formed between the elongated collar and the inner wheel. The drive shaft for the adjustment fitting, for example, is securely guided in such an elongated collar. On the other hand, such an elongated collar offers the possibility of providing a plain bushing for supporting the eccentric cam. 
         [0024]    The eccentric cam in the eccentric receiving space is supported between an inner plain bushing and an outer plain bushing in this design. Such support by means of plain bushings reduces the friction of the rotating eccentric cam with regard to the outer and inner wheels. 
         [0025]    An eccentric cam providing a rigid or variable overall eccentricity can be placed in the eccentric receiving space. Various designs are known from the prior art for forming a variable overall eccentricity, in particular. In an especially advantageous embodiment, two mutually rotatable eccentric cam parts forming a variable overall eccentricity are placed in the receiving space and are preloaded against one another to form a maximum overall eccentricity, wherein, furthermore, a carrier that is attached to the drive shaft in a rotationally fixed manner is provided which, when driven, acts on the eccentric cam parts in opposition to the preloading. When the drive shaft is not actuated, the eccentric cam parts are preloaded to form the maximum overall eccentricity. In this position, the eccentric cam presses the inner wheel against the outer wheel essentially free of play, so that undesired motion of the two fitting parts relative to one another is hindered. When the drive shaft is moved, the eccentric cam parts are rotated in opposition to the preloading, by which means the overall eccentricity is reduced. Play arises between the inner wheel and outer wheel, so that adjustment of the fitting parts relative to one another is possible. 
         [0026]    A continuous bearing journal is provided for supporting the components of the adjustment fitting, on which bearing journal the outer wheel is supported, in particular by means of the aforementioned central elongated collar. 
         [0027]    The first fitting part, in particular the ring gear, can be attached, in particular welded, to a backrest adapter, and for the second fitting part, in particular the inner wheel, to be attached, in particular welded, to a seat adapter. Since the adjustment fitting as such has no specific components for a particular vehicle seat, it is very versatile in its use. The adjustment fitting can be used for vehicle seats of different model variants by attaching a seat adapter or backrest adapter. In the configurations shown, the inner wheel remains fixed to the seat, while the outer wheel, including the drive shaft, wobbles during adjustment. The attached seatback moves in the same direction as the drive shaft. 
         [0028]    In another embodiment of the adjustment fitting, the external teeth of the inner wall of the inner wheel can be covered by a circumferential ring. As a result of the ring, which to a certain extent is placed on the external teeth, secure support of the radially inward-facing collar of the outer wheel is made possible. 
         [0029]    Heretofore, the outer wheel and inner wheel of an adjustment fitting  - equipped with a wobble mechanism have been implemented as precision stampings that are appropriately formed. Inner and outer wheels fabricated in this manner have an approximately constant material thickness at all points, corresponding essentially to the original sheet thickness. However, a constant material thickness is not suitable for the actual loads. Such fabrication also does not permit precisely toleranced positioning of different geometries on the component, as for example the location of an elongated wall relative to teeth. 
         [0030]    However, the disadvantages of the prior art manufacturing methods for producing an outer or inner wheel for a wobble mechanism can be overcome if the inner or outer wheel in question is fabricated as a cold extrusion part. Extrusion is a process of massive forming that produces both hollow and solid bodies in a single-stage or multi-stage fabrication process. In principle, in this process the material being processed, in particular metal, is caused to flow under the influence of high pressure. In this process, a die presses the blank workpiece through a tool opening of reduced cross-section, a female mold, that imparts shape. The forming itself generally takes place at room temperature, so that the process is referred to as cold extrusion. In this way, high dimensional accuracy and high surface quality are achieved. 
         [0031]    The advantage of using cold extrusion for fabricating the inner wheel and/or the outer wheel for an adjustment fitting lies in the possibility of strength-optimized designs, which may provide weight advantages under some circumstances. In addition, cost advantages can be achieved through savings in material. Moreover, tighter tolerances in the teeth and in coaxiality can be achieved through the use of cold extrusion, improving the homogeneity of actuation of the adjustment fitting. Since an adjustment fitting is a mass-produced part, cost advantages are achieved by the means that only one tool is required for fabrication. 
         [0032]    For the aforementioned inner wheel with elongated inner wall, cold extrusion permits, in particular, simplified creation of a geometry in which the external teeth are covered by a circumferential ring. By this means, the teeth are circumferentially bonded, so that strength is increased for the same assembled volume. A corresponding geometry cannot be achieved with other cold forming processes. At most, machining comes into consideration. 
         [0033]    For an outer wheel, which in the present case is implemented as a ring gear, the use of cold extrusion allows reinforcement of the material in especially stressed regions. This can be provided in the area of the inner elongated collar or in the vicinity of the teeth, for example. 
         [0034]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
           [0036]      FIG. 1  is an exploded view of an adjustment fitting for a motor vehicle seat, wherein the outer wheel is designed as a ring gear in which the inner wheel is supported by means of a retaining element, 
           [0037]      FIG. 2  shows the adjustment fitting from  FIG. 1  in a cross-sectional view, 
           [0038]      FIG. 3  shows a modified adjustment fitting in a cross-sectional view, 
           [0039]      FIG. 4  shows a cross-sectional view of an outer wheel produced by cold extrusion, and 
           [0040]      FIG. 5  shows a cross-sectional view of an inner wheel produced by cold extrusion. 
       
    
    
     DETAILED DESCRIPTION 
       [0041]      FIG. 1  shows an exploded view of an adjustment fitting  1  for a motor vehicle seat. The adjustment fitting  1  here includes a first fitting part  2  and a second fitting part  3 , which are rotationally adjustable relative to one another about an axis of rotation A. The first fitting part  2  has an outer wheel  4 , to which is attached, in particular by welding, a suitable backrest adapter  6  for later installation on a seat backrest. The second fitting part  3  includes an inner wheel  7  and a seat adapter  8  connected thereto for attachment to a seat base. 
         [0042]    The outer wheel  4  is designed as a ring gear  5  with a floor  9  and a circumferential, cylindrical outer wall  10 . Provided on the inside of the outer wall  10  are axially recessed internal teeth  12 . The outer wall  10  is extended in the axial direction beyond the internal teeth  12 . Also attached in the interior of the ring gear  5  is an elongated collar  14 , which surrounds a central bore. Into the ring gear  5  is placed the inner wheel  7 , which comprises circumferential external teeth  16  and a cylindrical inner wall  18  that is elongated in the axial direction beyond the external teeth  16 . 
         [0043]    To assemble the adjustment fitting  1 , the inner wheel  7  is placed in the interior space  20  of the ring gear  4 . Since the outside diameter of the inner wheel  7  has a reduced diameter as compared to the inside diameter  12  of the ring gear  4 , the latter rotates in a wobbling manner with its external teeth  16  rolling on the internal teeth  12  in the ring gear  5 . The number of teeth in the external teeth  16  is reduced as compared to the number of teeth in the internal teeth  12 , so that in one full circuit the inner wheel  7  rotates relative to the ring gear  5  by the difference in tooth count. 
         [0044]    The inner wheel  7  is inserted axially into the ring gear  5  down to the floor  9 . A retaining element  23 , which is designed as a retaining ring  24 , is then guided into the interior space  20  of the ring gear  5  following the inner wheel  7 , during which process it encloses the inner wall  18  of the inner wheel  7 . The retaining ring  24  has a diameter that is slightly reduced relative to the inside diameter of the outer wall  10 . Its inside diameter permits the wobbling motion of the enclosed inner wall  18  of the inserted inner wheel  7 . The external teeth  16  of the inner wheel  7  are located on a circumferential flange by which the inner wheel  7  is supported against the retaining ring  24 . 
         [0045]    The retaining ring  24  is moved toward the floor  9  of the ring gear  5  until a defined axial play of the inner wheel  7  is established. This can take place under the control of either force or distance. In a force-controlled insertion, manufacturing tolerances in the axial width of the external teeth  16  are compensated. At the desired end position, the retaining ring  24  is circumferentially welded to the inner side of the outer wall  10 . 
         [0046]    As a result of the inner wheel  7  inserted into the ring gear  5 , an eccentric receiving space to accommodate a driving eccentric cam is formed between the elongated collar  7  and the inner wall  18 . 
         [0047]    The seat adapter  8  includes an outer ring  27 , which overlaps the inner wall  18  of the inner wheel  7  via a central opening  28 . In the assembled state, the inner wall  18  is permanently welded to the outer ring  27  of the seat adapter  8 . 
         [0048]    A first eccentric cam part  30  and a second eccentric cam part  32  are placed in the eccentric receiving space  25  to form a variable overall eccentricity. These two eccentric cam parts  30 ,  32 , which together form the eccentric cam, are rotated relative to one another by means of a carrier plate  34  placed thereon, by which means their overall eccentricity is varied. To this end, the carrier plate  34  has lateral recesses  35 ,  36  in which the carrier projections  37 ,  38  of the first and second eccentric cam parts  30 ,  32  engage. The eccentric cam parts  30 ,  32  are preloaded by means of a spring element  40  to form a maximum overall eccentricity, wherein the inner wheel  7  is pressed against the outer wheel  4  without play in this position. 
         [0049]    Provided for driving the adjustment fitting  1  is a continuous bearing journal  42 , which includes an eccentric cover  44  that laterally engages the inner wall  18 . A square opening  45  is introduced into the cover  44  for driving. The bearing journal  42  is joined to the carrier plate  34  in a rotationally fixed manner. To retain the bearing journal  42 , a retaining ring  46  is provided on the opposite side. 
         [0050]    An inner plain bushing  48  and an outer plain bushing  49  are provided in order to reduce the friction of the eccentric cam parts  30 ,  32  on the elongated collar  14  and on the inner wall  18 . Here, the inner plain bushing  48  is placed on the elongated collar  14 . The outer plain bushing  49  is placed in the inner wall  18 . 
         [0051]    When the bearing journal  42  is actuated, the two eccentric cam parts  30 ,  32  are moved in opposition to the spring force by the carrier plate  34 , reducing the overall eccentricity. This results in play between the inner wheel  7  and the ring gear  5 , so that the eccentric cam can be rotated with a wobbling rolling of the inner wheel  7  in the ring gear  5 . The fitting parts  2 ,  3  are displaced relative to one another about the axis of rotation A. 
         [0052]      FIG. 2  shows the adjustment fitting  1  from  FIG. 1  in cross-section. Evident are the seat adapter  8 , which is attached to the inner wheel  7 , and the backrest adapter  6 , which is rigidly attached to the ring gear  5 . 
         [0053]    The inner wheel  7  is placed inside the outer wall  10  of the ring gear  4  and is supported between its floor  9  and the retaining ring  24 . In this design, the external teeth  16  are supported axially against the retaining ring  24 . The axial play of the inner wheel  7  with respect to the ring gear  5  is set by the axial positioning of the retaining ring  24 . The retaining ring  24  is welded to the outer wall  10  of the ring gear  5  in the adjusted position. The seat adapter  8  is welded to the outer wall  18  of the inner wheel  7  that is extended in the axial direction beyond the external teeth  16 . 
         [0054]    The two eccentric cam parts  30  and  32  are placed as an eccentric cam in the eccentric receiving space formed between the elongated collar  14  and the inner wall  18 . These eccentric cam parts are preloaded by means of the spring element  40  to form a maximum overall eccentricity. Visible in the cross-section shown is the carrier plate  34 , which works together with the carrier projection  37  of the first eccentric cam part  30 . 
         [0055]    The ring gear  5  is supported on the continuous bearing journal  42  by means of the elongated collar  14 . It is evident that the bearing journal  42  is secured on the side of the ring gear  4  by means of the retaining ring  46 . On the opposite side, the bearing journal  42  transitions to the cover  44 , whose laterally down-turned walls extend into the inner wall  18  of the inner wheel  7 . In this design, the cover is likewise of eccentric design corresponding to the overall eccentricity formed by the eccentric cam parts  30 ,  32 . The square hole  45  for attachment to a drive is evident in the interior of the bearing journal. 
         [0056]    When the bearing journal  42  is actuated, the overall eccentricity is reduced by means of the carrier plate  34 , which moves the eccentric cam parts  30 ,  32  relative to one another, so that the eccentric cam formed drives the inner wheel to circulate in the ring gear  5 . Since the inner wheel  7  is attached to the seat adapter  8  in a stationary manner, the result is a rotation of the backrest adapter  6 , and the backrest of the vehicle seat attached thereto, in the same direction as the bearing journal  42 . 
         [0057]    Evident from the cross-sectional view in  FIG. 3  is a modified adjustment fitting  100 , which comprises a first fitting part  102  and a second fitting part  103 , which are rotationally adjustable relative to one another about an axis of rotation. The first fitting part  102  has an outer wheel  104 , which is attached, in particular by means of welding, to a backrest adapter  106  for later installation on a backrest. The second fitting part  103  comprises an inner wheel  107  and a seat adapter  108  fastened thereto for attachment to a seat base. 
         [0058]    The outer wheel  104  is designed as a ring gear with a floor  109  and an outer wall  110 , wherein internal teeth  112  are placed on the outer wall  110 . The outer wheel  104  is divided along the internal teeth  112  and is composed of a first shell  113  and a second shell  114 . The second shell overlaps the external teeth  116  of the inner wheel  117 , placed on a raised inner wall  116  of the inner wheel  107 , with a circumferential collar  115 . In this way, the inner wheel  107  is held securely between the first shell  113  and the second shell  114  of the outer wheel  104 . In addition, the outer wheel  104  has a separately inserted dome  120 , which bears a circumferential elongated collar  121 . The design of a separate dome  120  offers the possibility of optimizing the different tribological properties with regard to support and transmission through appropriate selection of materials. 
         [0059]    Formed between the elongated collar  121  and the raised inner wall  116  of the inner wheel  107  is an eccentric, annular receiving space  124  in which a first eccentric cam part  126  and a second eccentric cam part  127  are placed for driving the inner wheel  107 . Under rotation, the two eccentric cam parts  126 ,  127  form a variable overall eccentricity and are preloaded by means of a spring element  130  to produce a maximum overall eccentricity. In this preloaded starting position, the external teeth  117  of the inner wheel  107  are pressed against the internal teeth  112  of the outer wheel  104  without play in the direction of maximum eccentricity, so that runout of the fitting parts  102 ,  103  relative to one another is not possible. 
         [0060]    For actuating the eccentric cam parts  126 ,  127 , a carrier plate  131  in which carrier projections  133  of the respective eccentric cam parts  126 ,  127  engage, is also placed in the eccentric receiving space  124 . The carrier plate  131  is attached in a rotationally fixed manner to the central drive shaft  134 , which in the present case is designed as a continuous bearing journal  135 . When the bearing journal  135  is driven or rotated, the eccentric cam parts  126 ,  127  are rotated against the preloading of the spring element  130  via the carrier plate  131  attached in a rotationally fixed manner, so that the inner wheel  107  now rests against the outer wheel  104  with play. The overall eccentric cam composed of the eccentric cam parts  126 ,  127  can be rotated, with the external teeth  117  of the inner wheel  107  rolling on the internal teeth  112  of the outer wheel  104 . One full rotation of the eccentric cam results in a rotation of the inner wheel  107  relative to the outer wheel  104  corresponding to a difference in tooth count between the external teeth  117  and the internal teeth  112 . 
         [0061]    In order to drive the bearing journal  135 , the journal has a square opening  136  on its top side. Provided on the opposite side is a receptacle for a further shaft which is provided for driving a corresponding adjustment fitting on the other side of the vehicle seat if desired. 
         [0062]    To reduce the friction between the eccentric cam parts  126 ,  127  and the inner wheel  107 , a plain bushing  137  is placed in the inner circumference of the inner wheel  107 . 
         [0063]    The bearing journal  135  is designed as a single piece with a cap  138 , which seals the eccentric receiving space  124  with respect to the outside. The cap  138  is designed in the shape of a disk and is offset radially with respect to the drive shaft  134 . In other words, the cap  138  is eccentric in design. The eccentric cap  138  additionally includes a sealing rim  140  that is drawn axially downward, which projects inside the eccentric receiving space  124 . By means of preloading directed radially outward toward the inner wall  116  of the inner wheel  107 , the circumferential sealing rim  140  seals the eccentric receiving space  124  with respect to the outside. The sealing rim  140  is made of a moldable elastomer, and is molded onto the bearing journal  135  by means of a two-component injection molding process. It can be seen that the axial length of the sealing rim  140  is dimensioned such that different variants of the adjustment fitting  100 , which differ in axial height, can be sealed with one and the same bearing journal  135 . In particular, manufacturing tolerances are compensated by this means as well. An axial offset of the sealing rim  140  with respect to the inner wall  116  within a certain limit does not change the sealing function. 
         [0064]    On the side facing away from the cap  138 , the bearing journal  35  is held on the adjustment fitting  100  by means of a locking disk  143 . The fitting parts  102 ,  103  are axially held together by the outer wheel  104  implemented as a ring gear. The locking disk  143  has a circumferential sealing rim  144 , and is held in a saucer-shaped recess  147  of the floor  109  or of the separate dome  120 . Axial preloading of the sealing rim  144  with respect to the floor  109  is achieved by means of a clip attachment of the locking disk  143  to the bearing journal  135 . As a result, not only does the locking disk  143  hold the bearing journal  135  in the adjustment fitting  100 , it also seals the radial gap between the bearing journal  135  and the dome  120 . On this side, too, penetration of dirt and, in particular, penetration of paint during the painting process, is thus reliably prevented. The sealing and securing functions can also be implemented here by two separate components. For example, the sealing rim  144  can also be implemented as a separate sealing ring on the locking disk  143 . 
         [0065]    The seat adapter  108 , in the form of a seat adapter plate, is attached circumferentially, in particular welded, to the inner wall  116  of the inner wheel  107 . The backrest adapter  106  is spaced axially away from the outer wheel  104  in order to permit rotation relative to one another. In addition, a disk-shaped central seal  150  is placed in the resultant axial gap  148  between the seat adapter  108  and the outer wheel  104 . In this way, the interior of the adjustment fitting  100  is fully sealed with respect to the outside. Neither dirt nor paint can enter the internal transmission parts through the outer annular gap between the inner wheel  107  and the outer wheel  104 , as well. 
         [0066]    The disk-shaped central seal  150  additionally has an outer sealing rim  152  with an essentially Y-shaped cross-section. Here, the two legs  153 ,  154  of the outer sealing rim  152  extend radially outward and spread axially against the seat adapter  108  and against the outer wheel  104 . In this way, dirt and, in particular, paint, is reliably prevented from penetrating the interior space of the adjustment fitting  100  through the axial gap  148 . 
         [0067]    In addition, the central seal  150  has an inner axial sealing rim  157  with which it is placed in the collar  115  of the outer wheel  104 . The inner sealing rim  157  has an inwardly curved end  158 . By this means, the internal transmission of the adjustment fitting  100  is protected from welding spatter during the manufacturing process. 
         [0068]      FIG. 4  shows a cross-section of an outer wheel  301  fabricated by cold extrusion. Visible are the elongated collar  303  surrounding a central bore  302 , and the raised outer wall  304  on whose inner circumference internal teeth  308  are formed. By means of cold extrusion, the material thickness of the outer wheel  301  is increased in the region  310  toward the elongated collar  303  and in the tooth region  312 . In this regard, the outer wheel  301  fabricated by cold extrusion has a distribution of material appropriate to loading. 
         [0069]      FIG. 5  shows a cross-section of a cold-extruded inner wheel  320 . The raised inner wall  321 , which carries external teeth  323  on its outer side, is evident. The external teeth  323  are circumferentially attached to a support geometry through a ring  325  located thereon. The strength of the inner wheel  320  is thus increased for the same assembled volume. Moreover, provision of the ring  325  achieves good material flow for forming of the external teeth  323  during cold extrusion. 
         [0070]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.