Abstract:
A fitting for a vehicle seat includes a first fitting part, a second fitting part which is rotatable relative to said first fitting part, a peripheral clamping ring which has a substantially L-shaped cross section, and which is connected to the first fitting part and extends over the second fitting part, and an intermediate ring which has a substantially L-shaped cross section, and which is arranged between the peripheral clamping ring and the second fitting part. A ledge is formed on the second fitting part, which ledge has an end surface and a cylindrical supporting surface. The supporting surface has a diameter which is smaller than the maximum outer diameter of the second fitting part, and the cylindrical supporting surface directly or indirectly supports the peripheral clamping ring.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a National Stage of International Application No. PCT/EP2012/000689 filed on Feb. 17, 2012, which claims the benefit of German Patent Application No. 10 2011 013 163.9 filed on Mar. 4, 2011, the entire disclosures of which are incorporated herein by reference. 
     FIELD 
     The invention relates to a fitting for a vehicle seat, in particular for a motor vehicle seat, having the features of the preamble of claim  1 . 
     BACKGROUND 
     EP1676502 A2 discloses a fitting which provides for a direct bearing of the metal fitting members on each other in the region of the outer periphery of the second fitting member, the clamping ring being of L-like form, being securely connected to the first fitting member at the outer periphery thereof or in the immediate vicinity thereof, having a cylindrical region and an inwardly extending edge region, wherein it engages behind the outer peripheral region of the second fitting member with the inwardly extending edge region and is in sliding contact with an outwardly directed lateral face of the first fitting member by means of a plurality of protrusions which project in an axial direction in the direction of the first fitting member. The bearing in a radial direction may be brought about either by means of the clamping ring or—alternatively—by means of the first fitting member which has a corresponding shoulder in the region of the outer periphery. This results in an unfavorable friction coefficient of the metal/metal material pairing. 
     DE102004010491 B4 discloses a fitting for a vehicle seat, of which a section is illustrated in the drawings. This fitting has a first fitting member  111 , a second fitting member  112  which is supported on the first fitting member  111  and which is rotatable relative thereto about a center axis, and a clamping ring  121  which is connected to the first fitting member  111  and engages over the second fitting member in order to axially secure it. In this instance, a plastics intermediate ring  131 , which is of L-like form and which is positioned in accordance with the L-like clamping ring  121  so as to extend on the inner surface and inner lateral face thereof, is arranged between the L-like clamping ring  121  and the second fitting member  112 . The intermediate ring  131  is connected to the second fitting member  112  in a rotationally secure manner and supports the first fitting member  111  in a radial direction with a bearing face which is formed by the inner surface of the cylindrical region and, in an axial direction, by the end face which extends in a radial direction. 
     SUMMARY 
     An object of the invention is to improve a fitting of the type mentioned in the introduction. This object is achieved according to the invention by a fitting having the features of claim  1 . The dependent claims relate to advantageous embodiments. 
     In this instance, a shoulder which is offset inwards relative to the maximum outer diameter and which has an end face which extends outwards in a radial direction and a cylindrical bearing face is constructed on the second fitting member, with the bearing face having a diameter which is smaller than the maximum outer diameter of the second fitting member, and the cylindrical bearing face supporting the clamping ring directly or indirectly, in particular preferably by means of an intermediate ring which is connected to the clamping ring in a rotationally secure manner. In contrast to the prior art, in this instance the bearing face is displaced from a position on the outer periphery of the second fitting member radially inwards, in the direction of the center axis of the fitting. In this instance, at least a region having a maximum outer diameter of the second fitting member projects radially outwards beyond the bearing face constructed on the second fitting member, that region being able to form a support for the clamping ring in the event of a crash, and thereby increasing the crash safety. In normal operation, however, that region is not in contact with the clamping ring. 
     In a particularly preferable manner, there is provided an intermediate ring which is connected in a rotationally secure manner to the clamping ring and which is supported at its inner surface on a shoulder of the second fitting member. By an intermediate ring being arranged between the clamping ring and a shoulder of the second fitting member, the play necessary for actuation can be compensated for in such a manner that disruptive rattling noises are also not produced without a backrest compensation spring. In order to keep the wear low, that is to say, to limit it to a small number of selected locations, the intermediate ring is carried in a rotationally secure manner by the clamping ring. 
     The clamping ring preferably has means for retaining the intermediate ring in a rotationally secure manner. Those means can be formed in particular by receiving members on the clamping ring and cams on the intermediate ring and/or by openings in the clamping ring and studs on the intermediate ring. However, it is also possible to have any other means for retaining the intermediate ring on the clamping ring in a rotationally secure manner. 
     The intermediate ring preferably has, for retaining the intermediate ring on the clamping ring in a rotationally secure manner, at least three cams, in particular preferably precisely six cams, which extend outwards in a radial direction from a substantially hollow-cylindrical region. Those cams become deformed resiliently and/or plastically when the fitting is assembled. The clamping ring preferably has at least a number of recesses which corresponds to the number of cams, by which recesses the cams are received. In this instance, the number may be twice, three times or four times as large, whereby the number of possible orientations of the intermediate ring in the clamping ring is increased. 
     The intermediate ring preferably has, for retaining the intermediate ring on the clamping ring in a rotationally secure manner, at least three studs, in particular preferably precisely six studs, which extend in an axial direction in the direction of the clamping ring from the edge region of the intermediate ring extending in a radial direction. The clamping ring has at least a corresponding number of openings in which the studs are positioned during assembly. 
     In a particularly preferable manner, the second fitting member and the intermediate ring are provided with chamfers in order to make it easier to push the intermediate ring onto the shoulder of the second fitting member. Damage to the sliding face of the intermediate ring is also thereby prevented. 
     The intermediate ring applies a radial pretensioning force to the second fitting member when the fitting is in the assembled state so that the second fitting member is retained in a centered state relative to the clamping ring (and therefore in relation to the first fitting member). 
     During correct use, a radial gap is provided between the second fitting member and the clamping ring whereas, in the event of a crash, there may be brought about additional direct support of the second fitting member on the clamping ring. 
     The fitting according to the invention can be used in a versatile manner, for example, in order to couple the backrest of a vehicle seat, to adjust the inclination of a thigh support or to otherwise fold and lock a member of the vehicle seat. The fitting may be a locking fitting as described, for example, in DE10105282 A1, or be constructed as a gear fitting, as described, for example, in DE10120854 C1, with two internal-toothed wheels and a central planet wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is explained in greater detail below with reference to two embodiments illustrated in the drawings, in which: 
         FIG. 1  is a three-part illustration of the first embodiment which shows three assembly steps—which are illustrated from right to left—for assembling a fitting according to the embodiment, only a clamping ring and an intermediate ring being illustrated in the first step, 
         FIG. 2  is a cross section transversely through a fitting during the assembly, 
         FIG. 3  is a detailed view of the detail III of  FIG. 2 , 
         FIG. 4  is another perspective illustration of the second assembly step of  FIG. 1 , 
         FIG. 5  is a cross section through the outer region of the fitting after complete assembly, 
         FIG. 6  is a schematic illustration of a vehicle seat having fittings according to the invention, 
         FIG. 7  is a detailed view of the outer region of the fitting, 
         FIG. 8  is a section along line VIII-VIII in  FIG. 7 , 
         FIG. 9  is a section along line IX-IX in  FIG. 1 , 
         FIG. 10  is a section through the bearing region according to the second embodiment and 
         FIG. 11  is a section through a fitting according to the prior art. 
     
    
    
     DETAILED DESCRIPTION 
     In the first embodiment, a fitting  1  in the form of a locking fitting has an approximately plate-like first fitting member  11  and a second fitting member  12  which is also approximately plate-like, which are rotatable relative to each other about a center axis A. The following direction indications relate to the cylindrical coordinate system which is defined by that center axis A. 
     As described in DE10105282 A1, whose disclosure content is expressly incorporated herein by reference, there are constructed on the first fitting member  11  guide segments which together guide at least one, in this instance two, radially movable, toothed bar(s) which cooperate(s) with a toothed ring of the second fitting member  12  in the form of an internal-toothed wheel in order to lock the fitting  1 . 
     A clamping ring  21  which is substantially L-shaped in cross section has, on the one hand, a substantially hollow-cylindrical region  22  which extends in a peripheral direction and with which it is arranged on the radially outwardly directed peripheral face of the first fitting member  11  and is securely connected thereto. On the other hand, the clamping ring  21  has, on the end face thereof facing away from the first fitting member  11 , an edge  23  which extends over the second fitting member  12  so as to form an annular end face and secures it in an axial direction. In a radial direction, play is provided between the second fitting member  12  and the clamping ring  21  in order to allow unimpeded rotational movement of the second fitting member  12 . 
     A plastics intermediate ring  31  which is substantially L-like in cross section and which is arranged on a shoulder  12   a , which is located radially not completely at the outer side (formed by a cylindrical bearing face  12   b  and an end face  12   c  which extends outwards substantially in a radial direction) on a bearing face  12   b  of the second fitting member  12 , is arranged in the region between the second fitting member  12  and the clamping ring  21 , which ring  31  has, in a transposed arrangement relative to the clamping ring  21 , an inner, substantially hollow-cylindrical region  32  and an adjoining, outwardly extending, annular edge region  33 . Consequently, the edge region  33  of the intermediate ring  31  extending transversely relative to the axial direction is positioned between the edge  23  of the clamping ring  21  and the second fitting member  12 . The hollow-cylindrical region  32  of the intermediate ring  31  is positioned on the substantially cylindrical inner peripheral face of the annular edge  23  of the clamping ring  21  and rotatably positioned on a substantially cylindrical outer surface of the shoulder  12   a  of the second fitting member  12  which forms the said bearing face  12   b  so that this region forms the bearing between the arrangement comprising the first fitting member  11  and the clamping ring  21  and intermediate ring  31  and the second fitting member  12 , that is to say, it supports the first fitting member  11  on the second fitting member  12 . In principle, the intermediate ring  31  may also be dispensed with (cf. second embodiment) so that the first fitting member  11  is supported directly on the second fitting member  12  by means of the clamping ring  21  which is securely connected thereto. According to the illustration of  FIG. 5 , the intermediate ring  31  adjoins, by means of its lateral face directed towards the second fitting member  12 , that face of the shoulder  12   a  extending in a radial direction, but a spacing may also be provided in this region, as illustrated in  FIG. 8 . In this instance, it may be seen in  FIG. 5  that the resilient/plastic deformation of the intermediate ring  31  which is produced during the assembly of the fitting  1  is not illustrated but instead an intersection of the intermediate ring  31  and the clamping ring  21  in the region of the cams  34  is illustrated. However,  FIG. 8  shows the deformed intermediate ring  31 . 
     The intermediate ring  31  has at least three, in this instance six, cams  34  which extend in a radial direction outwards into correspondingly deep receiving members  24  in the clamping ring  21 , which receiving members are, however, constructed to be larger in a peripheral direction (see  FIG. 7 ). Furthermore, the intermediate ring  31  has studs  34 ′ which extend in an axial direction from the edge region  33  of the intermediate ring  31  in the direction of the clamping ring  24  and which are received in corresponding openings  24 ′ of the clamping ring  21 . That arrangement ensures a rotationally secure carrying movement of the intermediate ring  31  by the clamping ring  21 . However, the rotationally secure carrying movement may also be brought about in any other suitable manner and, in particular, for example, only the cams  34  may be provided in conjunction with the receiving members  24  or only the studs  34 ′ may be provided in conjunction with the openings  24 ′ of the clamping ring  21 . 
     Furthermore, three resilient regions  35  are constructed on the intermediate ring  31  and extend outwards in a radial direction from the hollow-cylindrical region  32  and adjoin the inner side of the clamping ring  21 . Any tolerances, for example, diameter tolerances owing to water absorbed by the intermediate ring  31 , are thereby compensated for without the relative rotation between the first and second fitting members being impeded. The cams  34  further have a damping action. 
     The intermediate ring  31  is constructed so as to have a plurality of chamfers, a first chamfer provided on the outer periphery assisting during insertion of the intermediate ring  31  into the clamping ring  21 , that is to say, acting as an inclined introduction member. A stepped chamfer is constructed at the inner periphery at the side of the edge region  33 , the edge-side region being a space for adaptation to the form of the shoulder  12   a  in this region, and the region adjacent to the inner surface acts as an inclined introduction member for fitting to the second fitting member  12  and prevents damage to the inner surface which is rotatably supported on the bearing face  12   b  of the second fitting member  12  during use. 
     The fitting  1  is assembled as follows: in a first step, the fitting members  11  and  12 —independently of each other—and the additional elements which are not described in greater detail and which are arranged between the two fitting members  11  and  12  are preassembled and, in a separate manner, the intermediate ring  31  is inserted into the clamping ring  21 , as illustrated on the right in  FIG. 1 . Subsequently, the subassembly comprising the intermediate ring and clamping ring is placed on the fitting member subassembly and the two subassemblies are pressed together. 
     In this instance, the intermediate ring  31  has a slight overdimension in the region of the cams  34  before assembly. In order to simplify the pressing-together, the shoulder  12   a  and the corresponding region of the intermediate ring  31  have a chamfer (or rounding), as can be seen in  FIG. 8 . This can also be seen accordingly in the illustration of  FIG. 3  which shows a slightly modified intermediate ring  31 . Another bevelling or chamfering is provided on the outer edge of the intermediate ring  31  and the corresponding inner edge of the shoulder  12   a.    
     By being pressed together, the height of the cams  34  is reduced, the intermediate ring  31  becoming adapted to the geometry of the clamping ring  21  during assembly with resilient and/or plastic deformation. Owing to the cams  34  in conjunction with the receiving members  24  and the studs  34 ′ in conjunction with the openings  24 ′, the intermediate ring  31  is positioned in the clamping ring  21  in a rotationally secure manner. Furthermore, a given pretensioning force F, as indicated in  FIG. 8 , acts between the intermediate ring  31  and the second fitting member  12 , that is to say, the second fitting member  12  is supported with radial pretensioning. 
     According to the second embodiment schematically illustrated in  FIG. 10 , the intermediate ring is dispensed with. In this instance, the intermediate ring  21  is securely connected to the first fitting member  11  in accordance with the first embodiment in the hollow-cylindrical region  22  thereof. Unlike the first embodiment, the edge  23  is drawn inwards further in a radial direction so that the inner surface of the edge  23  is directly in abutment with the bearing face  12   b  of the shoulder  12   a  of the second fitting member  12 . Otherwise, the second embodiment corresponds to the first embodiment so that it is not discussed in greater detail. 
     According to a variant of the second embodiment which is not illustrated in the drawings, the end region of the clamping ring  21  in which the second fitting member is supported is provided with a friction-reducing coating. 
     In order to increase the safety, in particular the crash safety, the outer periphery of the second fitting member  12  has such dimensions that the outer surface can further be directly supported on the clamping ring  21  in the event of great loads, particularly without the intermediate ring  31  being arranged therebetween. During normal operation, however, a gap  37  is located between the two members, that gap  37  being able to be filled with lubricant in order to provide a damping layer and to prevent noise in the (undesirable) event of radial contact. 
     The fitting  1  according to the invention may be used in a vehicle seat  41  for a motor vehicle, for example, for adjusting the inclination, folding in a table-like manner or coupling of the backrest  43  thereof in some other manner. In general, a manually actuatable hand-operated lever  49  is located on a transmission rod which is aligned with the center axis A between two fittings  1  according to the invention and ensures synchronous unlocking thereof. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Fitting 
           11  First fitting member 
           12  Second fitting member 
           12   a  Shoulder 
           12   b  Bearing face 
           12   c  End face 
           21  Clamping ring 
           22  Hollow-cylindrical region 
           23  Edge 
           24  Recess 
           24 ′ Opening 
           31  Intermediate ring 
           32  Hollow-cylindrical region 
           33  Edge region 
           34  Cams 
           34 ′ Studs 
           35  Resilient region, 
           37  Gap 
           41  Vehicle seat 
           43  Backrest 
           49  Hand-operated lever 
         A Center axis 
         F Radial pretensioning force 
       
    
     PRIOR ART 
     
         
           111  First fitting member 
           112  Second fitting member 
           121  Clamping ring 
           131  Intermediate ring