Abstract:
A fitting ( 10 ) for a vehicle seat, in particular for a motor vehicle seat, includes a first fitting part ( 11 ) on which a ring gear ( 17 ) is formed, a second fitting part ( 12 ) on which a gear ( 16 ) is formed, the gear meshing with the ring gear ( 17 ). The two fitting parts ( 11, 12 ) are in a transmission connection with each other. A rotatably supported rotating eccentric ( 27 ) drives a relative rolling motion of the gear ( 16 ) and of the ring gear ( 17 ) and is driven by a carrier forming a driver ( 21 ). A bearing ( 28 ) for the eccentric ( 27 ) is arranged on the edge ( 12   b ) of a receptacle ( 12   a ) of one of the two fitting parts ( 11, 12 ), wherein the edge ( 12   b ) of the receptacle ( 12   a ) is partially extended along the circumference of the edge by means of individual axial projections ( 12   c ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a United States National Phase application of International Application PCT/EP2010/004026 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2009 038 562.2 filed Aug. 19, 2009, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a fitting for a vehicle seat having a first fitting part on which is formed a toothed ring, a second fitting part on which is formed a toothed wheel which meshes with the toothed ring, as a result of which the two fitting parts are in gear connection with each other, a rotatably supported circumferential eccentric, driven by a driver, for driving a relative rolling movement of the toothed wheel and the toothed ring and bearing for the eccentric. 
       BACKGROUND OF THE INVENTION 
       [0003]    A fitting of that type is known, for example, from DE 44 36 101 A1. A ring which is received by a small collar of the second fitting part is provided as a bearing for the eccentric. The formation of such a collar becomes more difficult as the hardness of the material increases. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the invention is to improve a fitting of the type mentioned in the introduction. According to the invention, a fitting for a vehicle seat, in particular for a motor vehicle seat, has a first fitting part on which is formed a toothed ring, a second fitting part on which is formed a toothed wheel which meshes with the toothed ring, as a result of which the two fitting parts are in gear connection with each other, and a rotatably supported circumferential eccentric, driven by a driver, for driving a relative rolling movement of the toothed wheel and the toothed ring, and a bearing for the eccentric. The bearing is arranged at the edge of a receptacle of one of the two fitting parts. The edge of the receptacle is partially widened along its circumference by means of individual axial projections. 
         [0005]    As a result of the fact that the edge of the receptacle is partially widened along its circumference by means of individual axial projections, a support bearing is created which has a sufficient axial dimension to receive and support the eccentric or the bearing of the eccentric. The projections are formed from the material of the fitting part. The formation of the projections, preferably as embossments, is also possible in the case of high-strength materials. An alternating formation—with respect to the two end faces of the fitting part—of the projections optimizes the axial dimension of the partially widened edge. In the present case, the invention replaces a collar formation in a gear fitting, but the invention can in principle also be applied to other sites on the vehicle seat which have a collar. 
         [0006]    The use of an eccentric epicyclic gear system in a fitting enables the inclination of the backrest of a vehicle seat to be adjusted continuously. The saving of a central pinion compared with a planetary gear system leads to the occurrence of a wobbling movement which is superimposed on the relative rotation of the fitting parts. The eccentric, which comprises, for example, two wedge segments braced apart by means of a spring, or a sickle-shaped member, is preferably supported, on its side opposite the afore-mentioned bearing of the one fitting part, for example on the inside, on a collar of the other fitting part. 
         [0007]    The invention is explained in more detail hereinafter with reference to an exemplary embodiment shown in the drawings. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    In the drawings: 
           [0009]      FIG. 1  is an exploded view of an exemplary embodiment according to the invention; 
           [0010]      FIG. 2  is a detailed view of the second fitting part; and 
           [0011]      FIG. 3  is a schematic representation of a vehicle seat. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]    Referring to the drawings in particular, a vehicle seat  1  for a motor vehicle has a seat part  3  and a backrest  4 , the inclination of which is adjustable relative to the seat part  3 . In order to adjust the inclination of the backrest  4 , a drive shaft  7 , which is arranged horizontally in the transition region between the seat part  3  and the backrest  4 , is rotated manually, for example, by means of a handwheel  5 , or in a motor-driven manner, for example by means of an electrical motor. On both sides of the vehicle seat  1 , the drive shaft  7  engages in a fitting  10  so that it is rotationally secure, in a manner which will be described later. The drive shaft  7  defines the adopted directional data of a cylinder coordinate system. 
         [0013]    The fitting  10  is in the form of a gear fitting in which a first fitting part  11  and a second fitting part  12  are connected to each other by means of a gear unit for displacement and fixing in position, to be more precise, by means of an eccentric epicyclic gear system, which in the present case is self-locking, as described, for example, in DE 44 36 101 A1, the relevant disclosure of which is expressly incorporated herein. 
         [0014]    With the mounting of the fitting  10 , the first fitting part  11  is, for example, connected tightly to the structure of the backrest  4 , i.e. it is fixed with respect to the backrest part. The second fitting part  12  is then connected tightly to the structure of the seat part  3 , i.e. it is fixed with respect to the seat part. Those assignments of the fitting parts  11  and  12  are preferred when the drive shaft  7  and the backrest  4  are to have the same direction of rotation, or when the position of the drive shaft  7  relative to the backrest  4  is to be constant in order, for example, to be able to fit to the structure of the backrest  4  an electrical motor rotating the drive shaft  7 . However, the assignments of the fitting parts  11  and  12  can also be exchanged, i.e. the first fitting part  11  would then be fixed with respect to the seat part and the second fitting part  12  would be fixed with respect to the backrest. The latter assignments of the fitting parts  11  and  12  are preferred when the radial spacings of the fastening points between the fitting  10  and a relatively thin metal backrest sheet are to be as large as possible. 
         [0015]    Each of the two fitting parts  11  and  12  can be approximately inscribed in a circular disk shape. The two fitting parts  11  and  12  are preferably composed of metal, in particular steel. In order to absorb the axially acting forces, i.e. in order to hold the fitting parts  11  and  12  together, an enclosing ring  13  is provided. Such a method of holding parts together by means of an enclosing ring is described, for example, in U.S. Pat. No. 6,799,806 A, the relevant disclosure of which is expressly incorporated herein. The preferably metal enclosing ring  13  is, with the mounting of the fitting  10 , connected tightly to the second fitting part  12 , being preferably first of all pressed on and then welded. Alternatively, the enclosing ring  13  is beaded, engaging over the second fitting part  12 . At one of its end faces, the enclosing ring  13  has an edge bent radially inwards by means of which it engages radially over the outside of the first fitting part  11 , optionally with the interposition of a sliding ring, without impeding the relative movement of the two fitting parts  11  and  12 . From a structural point of view, the two fitting parts  11  and  12  therefore together form a disk-shaped unit. 
         [0016]    In order to form the gear unit, an externally toothed wheel  16  is formed on the second fitting part  12 , and an internally toothed ring  17  is formed on the first fitting part  11 , the toothed wheel and the toothed ring meshing with each other. The diameter of the tip circle of the external toothing of the toothed wheel  16  is smaller by at least the depth of one tooth (of the toothed ring  17 ) than the diameter of the root circle of the internal toothing of the toothed ring  17 . A corresponding difference in the number of teeth of the toothed wheel  16  and the toothed ring  17  of at least one tooth permits a rolling movement of the toothed ring  17  on the toothed wheel  16 . 
         [0017]    On the side facing the toothed wheel  16 , the first fitting part  11  has, concentrically with the toothed ring  17 , a collar  19  which can be integrally formed on (i.e. formed in one piece with) the first fitting part  11  as a collar formation or which can be secured thereto in the form of a separate sleeve. A driver  21  is supported rotatably in the collar  19  by means of a hub  22 . The driver  21  is preferably composed of plastics material. The hub  22  of the driver  21  is provided centrally with a bore  23  for receiving the drive shaft  7 . The profile of the bore  23  is configured to fit the profile of the drive shaft  7 , in the present case a splined shaft profile. Adjoining its hub  22 , the driver  21  has a covering disk  25  which is formed in one piece with the hub  22  and which has a larger diameter than the hub. 
         [0018]    Supported on the collar  19  (with their curved inner surfaces) are two wedge segments  27  which support (with their curved outer surfaces) the second fitting part  12  by means of a slide bearing bush  28  which is pressed into the second fitting part  12  in a rotationally secure manner. The driver  21  has—spaced radially from the hub  22 —a driver segment  29  which engages with clearance between the narrow sides of the wedge segments  27  and which is formed in one piece with the covering disk  25  and the hub  22 . The mutually facing broad sides of the wedge segments  27  each receive, with a respective recess defined by projecting sections of material, a respective angled end finger of an omega spring  35  which presses the wedge segments  27  apart in the circumferential direction, it being possible during operation for the projecting material sections of the wedge segments  27  to touch and act on each other. 
         [0019]    The driver  21  is secured axially to the outside of the first fitting part  11  by a clipped-on securing ring  43 . Provided on the outside of the second fitting part  12 , between the radially outer edge thereof and the covering disk  25 , is a sealing ring  44  which is composed, for example, of rubber or soft plastics material and which is connected, in particular clipped, to the covering disk  25 . 
         [0020]    The wedge segments  27  (and the omega spring  35 ) define an eccentric which, in extension of the direction of eccentricity, presses the toothed wheel  16  into the toothed ring  17  at an engagement site so defined. When drive is effected by means of the rotating drive shaft  7 , a torque is first of all transmitted onto the driver  21  and then, by means of the driver segment  29 , onto the eccentric which slides along the slide bearing bush  28 , shifting the direction of eccentricity and thus shifting the site of engagement of the toothed wheel  16  in the toothed ring  17 , this presenting itself as a wobbling rolling movement, i.e. as a relative rotation with a superimposed wobbling movement. As a result, the inclination of the backrest  4  is continuously adjustable between several use positions. 
         [0021]    Depending on the mounting of the fitting  10 , the eccentric (i.e. the wedge segments  27 ) is supported by the second fitting part  12 , while it, for its part, supports the first fitting part  11 , or the relationships are exactly reversed, i.e. the eccentric rests on the first fitting part  11  and supports the second fitting part  12 . 
         [0022]    A receptacle  12   a , the edge  12   b  of which is defined by the material of the second fitting part  12 , is formed in the second fitting part  12  (in the present case concentrically with the toothed wheel  16 ). The slide bearing bush  28  is received by that receptacle  12   a  and rests against the edge  12   b  thereof (against the material of the second fitting part  12 ). The slide bearing bush  28  has an axial dimension (that is to say, along the axis of rotation of the eccentric) which is larger than the material thickness of the second fitting part  12 . In order to give the receptacle  12   a  the same axial dimension as that of the slide bearing bush  28 , in known fittings a small collar, which constitutes the edge  12   b  of the receptacle  12   a  and into which the slide bearing bush  28  is then pressed, is formed. 
         [0023]    According to the invention, the edge  12   b  of the receptacle  12   a  is partially widened in the circumferential direction in that individual projections  12   c  are formed from the material (defining the edge  12   b ) of the second fitting part  12  as a result of operations of pushing through axially, that is to say, the material of the second fitting part  12  is forced through in places along the edge  12   b  of the receptacle  12   a  (with constant spacing in the circumferential direction) and thereby forms the projections  12   c . This can take place, for example, by up to three quarters, preferably one quarter to half, of the material thickness of the second fitting part  12 , for example, a total of half to three quarters of the edge  12   b  being re-formed along the circumference of the edge  12   b . Each projection  12   c  is assigned a depression on the other end face of the fitting part  12  of the same axial dimension. With projections  12   c  provided in an axially alternating manner (and being otherwise identical), that is to say, with projections  12   c  along the circumference of the edge  12   b  alternating on the two end faces of the fitting part  12 , a bearing support is thus created for the slide bearing bush  28 , the axial dimension of which is, for example, twice the material thickness of the second fitting part  12  (normal material thickness plus twice the axial dimension of the projections  12   c ). With the solution according to the invention, it is in particular possible to use high-strength materials in the case of which it is no longer possible to produce a collar formation. 
         [0024]    The number of projections  12   c  along the edge  12   b  of the receptacle  12   a  and their respective dimensions in the circumferential direction and in the axial direction, and their embossments on one or both sides with an alternating direction or in an other order, depend on the specific demands made on the bearing support to be created. In principle, any variant is possible, the embodiment shown in the drawings being preferred. Instead of the slide bearing defined by the slide bearing bush  28 , a rolling bearing may also be provided which obtains a bearing support at the edge  12   b  of the receptacle  12   a  in a corresponding manner. 
         [0025]    While specific embodiments of the invention have been described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.