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, which gear meshes with the ring gear ( 17 ), whereby the two fitting parts ( 11, 12 ) are in a transmission connection with each other, and a rotating eccentric ( 27, 35 ) for driving a relative rolling motion of the gear ( 16 ) and the ring gear ( 17 ). The eccentric is driven by a carrier ( 21 ), wherein the eccentric ( 27, 35 ) is rotatably supported in a collar ( 38 ), which is associated with one of the two fitting parts ( 11, 12 ), or in a bushing ( 28 ) sitting in said collar ( 38 ) in a rotationally fixed manner. A blocking element ( 50 ) for the eccentric ( 27, 35 ) is operative at least at times between the eccentric ( 27, 35 ) and the bushing ( 28 ). The bushing ( 28 ) has teeth ( 28   a ) pointing radially outward and the blocking element ( 50 ), which surrounds the bushing ( 28 ) annularly, has at least one, in particular two, tooth segments ( 58 ) pointing radially inward for interacting with the teeth ( 28   a ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Phase application of International Application PCT/EP2010/004717 and claims the benefit of priority under 35 U.S.C. § 119 of German Patent Application DE 10 2009 039 461.3 filed Aug. 26, 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, in particular for a motor vehicle seat, having a first fitting part on which a toothed ring is formed, a second fitting part on which a toothed wheel is formed which meshes with the toothed ring, as a result of which the two fitting parts are in gear connection with each other, a circumferential eccentric, driven by a driver, for driving a relative rolling movement of the toothed wheel and the toothed ring, the eccentric being rotatably mounted in a collar which is assigned to one of the two fitting parts, or in a bearing bush which is supported in a rotationally secure manner in this collar, and a locking element for the eccentric that is at least temporarily effective between the eccentric and the fitting part which is provided with the collar. 
       BACKGROUND OF THE INVENTION 
       [0003]    A fitting of this type is known, for example, from DE 10 2007 010 078 B4. The locking element which is described there, denominated braking element, in its unlocked state, is arranged within the radius of the bearing bush. If the fitting is exposed to a torque on the drive output side, for example by shaking or pushing at the backrest, a wedge segment is allowed to move slightly. The adjacent Omega spring acts upon the locking element which tilts, thus going over into a locked state, in which it cooperates with a toothing which protrudes axially from the bearing bush, in order to avoid a further movement of the wedge segment. A so-called “spooling”, i.e. a rotation of the fitting in tiny steps is avoided. 
       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 is provided comprising a first fitting part on which a toothed ring is formed, a second fitting part on which a toothed wheel is formed which meshes with the toothed ring, as a result of which the two fitting parts are in gear connection with each other, a circumferential eccentric. A driver is provided for driving a relative rolling movement of the toothed wheel and the toothed ring. The eccentric is rotatably mounted in a collar which is assigned to one of the two fitting parts, or in a bearing bush which is supported in a rotationally secure manner in this collar. A locking element for the eccentric is at least temporarily effective between the eccentric and the fitting part which is provided with the collar. The bearing bush or the collar has a radially outward facing toothing. The locking element which surrounds the bearing bush and/or the collar in a ring-shaped manner has at least one, particularly two, radially inward facing toothed segments for cooperating with the toothing of the bearing bush or the collar. 
         [0005]    Radially outside the collar with the bearing bush, there is space so that the bearing bush, for the necessary bearing support of the eccentric, has a certain width which is larger than the material strength of the assigned fitting part. Due to the fact that the bearing bush or the collar are provided with a radially outward pointing toothing and that the locking element which surrounds the bearing bush and/or the collar in the form of a ring has at least one, in particular two radially inward pointing toothed segments for cooperating with the toothing of the bearing bush, said space radially outside the bearing bush can be better made use of. The cooperation of the locking element with the bearing bush, compared to the cooperation with the back side of the toothed wheel, has the advantage that toothed wheel and toothed ring can be configured independently of the bearing of the eccentric. Having a locked state when the fitting is not activated, i.e. when the driver is not driven (non-driven) offers more security than if external influences first have to create the locked state. 
         [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, 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 the exemplary embodiment according to the invention; 
           [0010]      FIG. 2  is a perspective partial view of the exemplary embodiment without the driver; 
           [0011]      FIG. 3  is a detailed view of a portion shown in  FIG. 2 ; 
           [0012]      FIG. 4  is a further detailed view of a portion shown in  FIG. 2 ; 
           [0013]      FIG. 5  is a schematic view of a vehicle seat according to the invention; and 
           [0014]      FIG. 6  is a perspective partial view of a modification. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    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. 
         [0016]    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 (corresponding U.S. Pat. No. 5,634,689 is incorporated by reference in its entirety). 
         [0017]    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. 
         [0018]    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 by reference. 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. 
         [0019]    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 . 
         [0020]    On the side facing the toothed wheel  16 , the first fitting part  11  has, concentrically with the toothed ring  17 , a first 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 first 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. 
         [0021]    Supported on the first 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 seated in 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. 
         [0022]    The slide bearing bush  28  is received by a receptacle in the second fitting part  12 , the slide bearing bush  28  preferably being pressed into the second fitting part  12 . The material of the second fitting part  12 , which forms the edge of such receptacle and over which the slide bearing bush  28  axially protrudes, is formed by a second collar  38  of the second fitting part  12 . 
         [0023]    The slide bearing bush  28  is consequently received in a rotationally rigid manner in this second collar  38 . Just like the first collar  19 , the second collar  38  can be formed on the second fitting part  12  (i.e. formed in one piece) or be fixed to it as a separate sleeve. 
         [0024]    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 . 
         [0025]    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. 
         [0026]    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 . 
         [0027]    Under dynamic operating conditions, shaking or pushing of the backrest  4  (shock-type torque on the drive output side) can cause the fitting  10  to “spool”, i.e. the fitting  10 , for minimum periods of time, is no longer free of backlash, so that it turns in tiny steps. To avoid this, a locking element  50  is provided. The basic principle of the locking element  50  is described in DE 195 48 809 C1, the relevant disclosure of which is expressly incorporated herein (corresponding U.S. Pat. No. 5,871,414 is herby incorporated by reference in its entirety) . The locking element  50  is formed in one piece of spring steel and—axially on the side facing the covering disk  25 —radially encircles the outside of the slide bearing bush  28 , i.e. surrounds it in the form of a ring. Like in the DE 195 48 809 C1, the locking element  50  is provided with two axially protruding angled supporting fingers  52  for cooperating with the driver  21 , precisely speaking with two stops  25   a  at the covering disk  25 . The end fingers of the Omega spring  35  engage through sufficiently big openings  54  of the locking element  50 , in order to reach the wedge segments  27 . 
         [0028]    The slide bearing bush  28  axially protrudes over the second collar  38  of the second fitting part  12 . In the axially protruding part, the slide bearing bush  28  has a radially outward facing toothing  28   a.  The locking element  50  is supported at this toothing  28   a  by means of preferably three bearing segments  56 . The bearing segments  56  axially protrude from the locking element  50 , on the side facing the second fitting part  12 . The axial dimension of the bearing segments  56  corresponds to the axial dimension of the toothing  28   a,  i.e. of the protruding part of the slide bearing bush  28 . At each of the two supporting fingers  52 , one of the three bearing segments  56  can be provided, while the third bearing segment  56 , which can be formed differently from the two others, can be provided, for example, at the openings  54 . A pre-tension in the locking element  50 , for example, due to a slightly elliptic shape, provides for a good seat of the locking element  50  on the slide bearing bush  28  in the area of the bearing segments  56 . Between the bearing segments  56 , the locking element  50  is in some places spaced apart from the slide bearing bush  28 . 
         [0029]    The ring-shaped locking element  50  additionally is provided with two toothed segments  58 , which face radially inward. The toothed segments  58  are arranged, for example, close to the supporting fingers  52  and, in the peripheral direction, adjacent to the bearing segments  56 . When the fitting  10  is not driven, it locks due to the maximum backlash-free eccentricity of the wedge segments  27  upon which the Omega spring  35  acts and due to the friction between the wedge segments  27  and the collar  19 . Then, also the toothed segments  58  of the locking element  50  mesh with the toothing  28   a  of the slide bearing bush  28 . If, under the named dynamic operating conditions, eccentricity were to be reduced temporarily, so that the wedge segments  27  abruptly move slightly, this will have no influence on the meshing between the toothed segments  58  and the toothing  58   a.  The locking element  50 , by the contact of the end fingers of the Omega spring  35  with the edge of the opening  54 , rather prevents the Omega spring  35 —and consequently the wedge segments  27 —from rotating further. 
         [0030]    When the fitting  10  is driven, the leading stop  25   a  of the driver  21  presses against the assigned supporting finger  52  of the locking element  50 . The locking element  50  deforms, so that the toothed segments  58  get detached from the toothing  28   a  of the slide bearing bush  28 , before the driver segment  29  acts upon the wedge segment  27  on the side opposed to the leading stop  25   a.  With every further rotation of the driver  21 , the locking element (and consequently also the openings  52 ) is taken along in an unlocked state. The wedge segments  27  can thus move unhindered. When the rotation of the driver  21  ends, the pre-tension of the locking element  50  again provides for its locked state. 
         [0031]    A modification of the exemplary embodiment corresponds to the exemplary embodiment, unless otherwise described, so that identical and identically acting components have the same reference numerals. In this modification, a radially outward facing toothing  60   a  is formed on the second collar  38 , such toothing cooperating with the locking element  50  (which surrounds the second collar  38  like a ring). The slide bearing bush  28  correspondingly is flush with the second collar  38 , i.e. without axial projection and without toothing  28   a.  The second fitting part  12  of this modification is shown in  FIG. 6 . The second fitting part  12  ends at the toothed wheel  16 , so that the enclosing ring  13  is reasonably arranged on the other front side of the first fitting part  11 , in order to be able to engage into the second fitting part  12  and to be fixed at the first fitting part  11  (with a slightly smaller diameter). If the inner side of the second collar  38  or the outer side of the wedge segments  27  are suitably coated, the slide bearing bush  28  can be completely omitted. 
         [0032]    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.