Abstract:
A wobble joint fitting for an adjustment device of a motor vehicle seat comprises a first fitting part, a toothed eccentric gear that has an eccentric hole and a flange, and an eccentric comprising a rotatable drive part, a control part and wedge segments, the control part comprising control surfaces that come to abut against the wedge surfaces. The fitting further comprises a second fitting part that is adjustable with respect to the first fitting part. A latching part is provided which has at least one latching tooth, biased only in an actuation position of the latching part into engagement with a latching recess, and having an actuating flank. The control part comprises an actuating portion which abuts against the actuating flank and, during a rotary movement of the control part, presses the latching tooth into abutment against the flange, and biases it into engagement into a latching recess.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Application No. 10 2009 060 430.8 filed Dec. 22, 2009 and German Application No. 10 2010 030 002.0 filed Jun. 11, 2010, which are hereby incorporated by reference in their entirety as part of the present disclosure. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a wobble joint fitting for an adjustment device of a motor vehicle seat, in particular for a backrest joint fitting, with a) a first fitting part comprising an internal ring gear, b) a toothed eccentric gear that engages this internal ring gear and that has an eccentric hole and a flange, c) an eccentric comprising a rotatable drive part, a control part and wedge segments, the control part comprising control surfaces that come to abut against the wedge segments, and d) a second fitting part that is adjustable with respect to the first fitting part. 
         [0003]    Wobble fittings are disclosed in DE 10 2009 001 309 A1, DE 10 2005 054 489 B4, DE 10 2004 007 043 B2, DE 102 030 06 A1 and DE 15 80 541 A, for example. The wrap spring is supposed to provide a run-off protection. Though in principle, the wobble joint fitting is self-locking; there are, however certain loads during the driving operation or in other situations which lead to the wobble joint fitting automatically becoming displaced nevertheless. This is referred to as the fitting running off. A wrap spring is intended to counteract this. 
         [0004]    A wobble joint fitting is known from DE 195 48 809 C1 which, for preventing run-off, comprises a blocking ring provided in the radial plane between the wedge segments and the control part and which comprises on its outer circumference at least one latching tooth which in the normal position engages a counter toothing of the toothed eccentric gear. It is elastically biased into the engagement position. It can be withdrawn from the engaging position by means of fittings of the drive part by the drive part being rotated. The engaging position is thus cancelled and the rotary movement of the wobble joint fitting is enabled. 
         [0005]    This solution employs a relatively complicated component forming the blocking ring. Noise-free operation is not always achieved; a development of noise between at least one latching tooth and the counter toothing can virtually not be precluded. As a rule, there is a ratchet sound. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, it is the object of the invention to further develop the wobble joint fitting of the type mentioned herein in such a manner that the run-off protection operating with a positive fit is configured to be secure and more noise-free, is not noticed in normal operation and only engages in the case of a run-off. 
         [0007]    Based on the wobble joint fitting of the type mentioned in the introduction, this object is achieved by the flange having latching recesses distributed over its circumference, by a latching part being provided which has at least one latching tooth, which in a normal position of the latching part is out of engagement with the latching recess and is only biased in an actuation position of the latching part into engagement with a latching recess, by the latching part further having an actuating flank, and by the control part comprising an actuating portion which comes to abut against the actuating flank and, during a rotary movement of the control part, presses the latching tooth into abutment against the flange, so that the latching tooth is biased for engagement into a latching recess. 
         [0008]    This solution is advantageous in that a positive fit occurs only, respectively, between one latching tooth and one latching recess. Only the latching tooth required for the positive fit is biased into the engagement position by a cooperation of the actuating flank and the actuating portion once a run-off occurs. The engagement of the latching tooth and the latching recess only takes place if a run-off actually happens. The at least one latching tooth is thereby located outside the latching recess during normal operation, and a ratchet noise is reliably avoided during normal operation. 
         [0009]    The blocking segments move during a run-off, they entrain the control part. Via its actuating portion, the control part presses against the actuating flank of the latching part. The latching tooth thus approaches the flange and comes into contact with the flange. It can thus engage into a latching recess. The engagement takes place as soon the relative movement has proceeded so far that the latching recess is located under the latching tooth. 
         [0010]    Preferably, a latching tooth is provided for each direction of rotation. Therefore, two latching teeth are formed on the control part. Only one latching tooth is actively in each case in an engagement during a run-off; the other one of the two latching teeth remains out of engagement. This second latching tooth therefore cannot cause any ratchet noise. The first latching tooth likewise virtually does not cause any noise. 
         [0011]    Preferably, the wobble joint fitting has a wrap spring having an annular spring abutting against the flange. The latching part is retarded by this wrap spring in the case a run-off movement. The cooperation between the actuating portion of the drive part and the actuating flank of the latching part is thus simplified. It is thus prevented more reliably that the drive part does not simply move the latching part with it in the case of a run-off movement. In addition, the wrap spring can be designed in such a manner that it also retards the run-off of the fitting itself; in this regard, reference is also made to the teaching of the aforementioned DE 10 2009 001 309 A1, the disclosure of which in its entirety belongs to the disclosure of the present application. 
         [0012]    Preferably, the latching part is connected to the wrap spring, in particular integrally connected. The retarding action caused by the wrap spring is thus transmitted directly to the latching part. In another embodiment, a positive fit connection can be provided between the wrap spring and the latching part. Other configurations are possible. This includes a connection of the wrap spring and the latching part by welding, in particular laser welding. 
         [0013]    Preferably, the latching part and/or the annular spring extend over an angle of less than 360°. Thus, the annular spring, which is preferably configured as a spring ring, can be made very flat and requires only very little construction space. As opposed to prior art, no genuine wrap spring is thus used, which is wrapped many times, at any rate at least three times, typically at least 5 times, and accordingly has many windings; instead, a wrap spring is used that extends over less than 360°. Preferably however, it differs as little as possible from 360°. Such a spring can be configured as a flat part, in particular as a stamped sheet steel part. Commercially available springs as they are generally known as axial securing elements on shafts or axles for securing the position or for guidance can be utilized, see for example Dubbel, Taschenbuch des Maschinenbaus, 20. Auflage, Stichwort G36 (Pocket Book of Mechanical Engineering, 20 th Edition, Catchword G 36). Such securing elements are standardized in German standards DIN 471 T1 and T2, DIN 472 T1 and T2, DIN 983 and DIN 984 issued by the German national organization for standardization. They are also referred to as circlip rings. The advantage thereof is that they are very flat, they are planar. Intersections between windings are obviated. Their constructional height is significantly less than 1 mm; it may be less than 0.3 mm. Such a small component part can also be accommodated later inside an existing fitting. This is a great advantage over prior art. 
         [0014]    In the assembled state, the latching part is located between components of the wobble joint fitting and not outside of these components or the wobble fitting. In particular, it is located within a space delimited by the fitting parts. Preferably, the latching part and/or annular body of the annular spring are located between the toothed eccentric gear and the eccentric, or in an annular space between the counter toothing of the eccentric gear and the flange. This counter toothing of the external toothing was produced by means of a pressing process, e.g. by pushing, during the production of the external toothing. 
         [0015]    The annular spring is preferably controlled via its two end portions. They are configured in such a way that they can be gripped. For example, they protrude radially inwards or outwards; they may also, if necessary additionally, protrude axially relative to the actual ring. It is also possible to use the holes, which are present in a commercially available circlip ring, by fixing pins, for example, in these holes. 
         [0016]    Preferably, the control part is responsible for controlling the annular spring. In an advantageous development, it comprises a control flank for each wedge segment, and in addition has opposite control surfaces between which the end portions of the annular spring are located. When the control part rotates, the one or the other control surface strikes against the adjacent end portions of the annular spring. In the normal position, the control surface abuts against these end portions with little pressure, or there is a small air gap between the control surfaces and the end portions. 
         [0017]    In an advantageous development, a lug located on the control part, in particular on a wheel of the control part, reaches between the end portions of the annular spring. An adjusting movement is initiated in this manner. When the lug, with a lug flank located to the front in the direction of rotation, presses against the adjacent end portion and drives it, the end portion preferably lifts slightly from the flange. The retarding action is thus reduced. 
         [0018]    In an advantageous implementation, the annular spring is thicker in its 6 o&#39;clock area, which is diametrically opposite from the two end portions, than in another area of the extent of the ring. Its thickness decreases continuously starting from this area. This configuration is known from circlips. 
         [0019]    Other advantages and features of the invention become apparent from the other claims as well as from the following description of three very similar exemplary embodiments of the invention, which are to be understood not to be limiting and which will be explained below with reference to the drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a perspective assembly view of the wobble joint fitting in a first exemplary embodiment. 
           [0021]      FIG. 2  is an axial view in a direction corresponding to II-II in  FIG. 1 . 
           [0022]      FIG. 3  is a perspective view of a component which forms the annular spring and the latching part at the same time. 
           [0023]      FIG. 4  shows a sector from 12 o&#39;clock to 3 o&#39;clock of an axial view corresponding to  FIG. 2 , with the normal position being depicted. 
           [0024]      FIG. 5  shows a sector view as in  FIG. 4 , with the actuation position being depicted. 
           [0025]      FIG. 6  shows an axial view similar to  FIG. 2  for a second exemplary embodiment, with a spring and a control part being provided in addition to  FIG. 2 . 
           [0026]      FIG. 7  is a perspective view of the component which forms the annular spring and the latching part at the same time, similar to  FIG. 3 , but in a different configuration. 
           [0027]      FIG. 8  shows a view with a viewing direction corresponding to VIII-VIII in  FIG. 1  with a perspective view. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]      FIGS. 1 to 5  show a first exemplary embodiment which is explained in more detail below.  FIG. 6  shows a second exemplary embodiment,  FIGS. 7 and 8  show a third exemplary embodiment. The second and third exemplary embodiments largely match the first exemplary embodiment and are explained only where they deviate therefrom. 
         [0029]    The wobble joint fitting comprises a first fitting part  20  and a second fitting part  22 . The angular position of these fitting parts  20 ,  22  relative to each other can be changed in the known manner by rotating a drive part  24 . In the exemplary embodiment shown, a toothed eccentric gear  26  is formed on the second fitting part  22 . It is in a toothed engagement with an internal ring gear  28  formed on the first fitting part  20 . A bridging part  29  retained on the first fitting part  20  reaches over the second fitting part  22  and connects the fitting parts  20 ,  22 . 
         [0030]    In another embodiment not shown herein, the eccentric gear  26  is separate from the second fitting part  22 . The second fitting part  22  is configured in a similar manner as the first fitting part  20 ; it thus comprises an internal ring gear  28 . The eccentric gear  26  is in engagement with the two internal ring gears of the two fitting parts  20 ,  22 . In this embodiment, the first fitting part  20  and the second fitting part  22  do not move radially relative to each other during an adjustment; only a rotational movement takes place. 
         [0031]    In the exemplary embodiment shown, an eccentric hole  30  is provided on the eccentric gear  26 ; it is disposed centrally of the ring gear of the eccentric gear  26 . An eccentric engages into this eccentric hole  30 . It is realized in part by the drive part  24  and in part by the two wedge segments  36 . The wedge segments  36  are biased against each other in the circumferential direction by a spring  38 , which in this case is configured as a spring in the shape of the Greek letter omega. Freedom from clearance is thus obtained.  FIG. 1  also shows several bearing bushes  39 ,  40  and  41  disposed between the eccentric hole  30  and a collar  32 . 
         [0032]    In a first exemplary embodiment according to the  FIGS. 1 to 5 , the drive part  24  is formed as one piece. In the second exemplary embodiment according to  FIG. 6 , it has a two-piece configuration and comprises a wheel and a control part  34 . The wheel is not shown in  FIG. 6 ; in a view according to  FIG. 1 , it looks similar to the drive part  24  from the first embodiment. The control part  34  comprises two control flanks; they lie opposite from the narrow sides of the wedge segments  36 . The control flanks extend radially. The control part  34  further comprises two projections protruding into an annular space between a flange  50  and a counter toothing of the external toothing of the eccentric gear  26 . They each comprise an actuating portion  44 . In the first exemplary embodiment, these control flanks and the actuating portions  44  are provided on the drive part  24 . 
         [0033]    An annular spring  48  or spring ring is provided between the eccentric and the eccentric gear  26 . The eccentric gear  26  comprises an annular collar which forms on its cylindrical outer surface the flange  50  on which the inner edge of the annular spring  48  rests. By way of kinematic inversion, the flange  50  can also delimit an internal cylinder and the annular spring  48  can abut against the internal cylinder. 
         [0034]    The annular spring  48  comprises an annular body  52  which extends over about 330 to 340° and is made from flat material, as well as two end portions  54 . The annular spring  48  is preferably of one piece. 
         [0035]    In contrast to a normal circlip, the end portions  54  are bent out from the plane of the annular body  52 . They thus extend in the axial direction, as can be seen from FIG.  1 . Two stop faces are formed in the circumferential direction on each end portion  54 . They lie in the opposite direction from each other and are explained in more detail below. 
         [0036]    In the assembled state, an inner stop face of each end portion  54  is close to or in contact with the lug  46 . This can be seen, for example, from  FIG. 3  of the aforementioned DE 10 2009 001 309.  FIG. 3  shows the normal state, the fitting is blocked. Starting from the position according to  FIG. 3 , the annular spring  48  is controlled as follows: If the drive part  24  is rotated and the lug  46  thus moves in the circumferential direction, for example in the clockwise direction, the corresponding lug flank abuts hits the internal stop flank of the right-hand end portion  54 . Since the contact surface does not extend radially but rather deviates at least 5°, preferably at least 10°, from the radial and since the contact plane forms an angle with an associated diameter and the orientation is such that the inner stop flanks almost lie on parallel planes, the lug  24  lifts the right end portion  54  slightly from the flange  50  upon hitting it. For the subsequent drive movement, the annular spring  48  therefore is slightly lifted and has a less of a clamping action than before. 
         [0037]    Latching recesses  58  are disposed uniformly distributed on the flange  50 . They are substantially V-shaped and symmetrical relative to a radial. They are configured as notches. A total of 16 of such latching recess  58  is provided. A different number is possible, for example twice the number. 
         [0038]    A latching part  60  is located in the annular space. It is also configured as a flat annular spring  48  extending over about 250 to 320°. Preferably, the annular body  52  of the latching part  60  extends over a smaller total angle than the annular body  52 ; the difference is preferably about 20 to 50°. The latching part  60  has thickened portions on its free ends on the end sides. There, one actuating flank  62 , respectively, is provided on the narrow outer side, and one latching tooth  64 , respectively, is provided on the inner side. The latching tooth  64  and the actuating flank  62  substantially lie on a radial, the angular offset is small; it is between 5 and 15°. The actuating flank  62  rises towards the free end so that the result is the thickened portion on the side of the end which is apparent from the figures. The latching part  60  is located above the annular body  52 . The thickness of the latching part  60  plus the thickness of the annular body  52  together is less than the depth of the annular space in the axial direction. 
         [0039]    The latching part  60  is kinematically connected to the annular body  52 . Both are produced integrally in the exemplary embodiment shown. For this purpose, a pre-cut part is produced from a thin spring sheet; the pre-cut part has the approximate shape of an eight, however, the circles of the eight are respectively open at their extremes. Described in other The words, the pre-cut part has the shape of two U-parts put together at their bases in a mirror image arrangement. This pre-cut part has a web which interconnects the two areas that later form the annular body  52  and the latching part  60 . This web is bent by 180° so that the latching part  60  comes to rest above the annular body  52 . The resulting component is shown in  FIG. 3 . 
         [0040]    When a joint fitting runs off, the following takes place: In the case of a run-off, the wedge segments  36  lose their purchase; more specifically, the wedge segment  36  which is in the clamping position loses its purchase. It thus moves in the circumferential direction and hits a control flank of the drive part  24  or of its control part  34 . The latter is thus rotated as well. This rotary movement leads to the actuating portion  44  sliding along the actuating flank  62  and to the latching part&#39;s  60  thickened portion on the end delimited thereby being pushed radially inwardly. The latching tooth  64  located on the inside thus comes into contact with the flange  50 . This takes place against the spring action of the latching part  60 . Due to the resilient bias, the latching tooth  64  is normally not in contact with the flange  50 . The contact with the flange  50  now causes the latching tooth  64  to be able to engage a latching recess  58 . A continuation of the rotary movement driven by a run-off may be possibly necessary for this engagement. Once the latching tooth  64  has engaged a latching recess  58 , a positive fit is achieved. The run-off movement thus comes to a standstill. 
         [0041]    The normal position is reached again in the case of a subsequent movement of the fitting. 
         [0042]      FIG. 4  shows the normal position. The latching part  60  is out of engagement with a latching recess  58 ; the latching tooth  64  does not abut against the flange  50 . The actuating flank  62  is not shown in  FIG. 4 . 
         [0043]      FIG. 5  shows the actuation position. The actuating flank  62  has been pushed inwards by the actuating portion  44  and is held in that position. This takes place against the resilience of the latching part  60 . The latching tooth  64  is in engagement with a latching recess  58 . In this engaging position, a run-off is hindered. 
         [0044]    The fitting has a largely symmetrical structure. Both the annular body  52  as well as the latching part  60  are mirror-symmetrical to a plane of mirror symmetry defined by a radial and an axis of rotation  23 . 
         [0045]    A two-part configuration of the drive part  24  as shown in  FIG. 6  has the following advantage: In  FIG. 6 , the lug  46  is disposed on the wheel. The control flanks and the actuating portions  44  are provided on the control part  34 . The control part  34  is able to be rotated within certain limits of, for example, maximally 30 to maximally 60° relative to the wheel. In the case of a run-off, only the control part  34  rotated; the wheel remains still. Because the wheel remains still, its lug  46  also remains still, so that the clamping action of the annular spring  48  is not canceled. 
         [0046]    As can be seen in  FIG. 6 , the spring  38  is located between the control part  34  and the wheel of the drive part  24  not shown in  FIG. 6 . 
         [0047]    Preferably, the annular spring  48  and/or the latching part  60  are a stamped part. The end portions  54  have been bent later, after the stamping process. 
         [0048]    Preferably, the latching part  60  and/or the spring ring  48 , with regard to their geometry, are formed in such a manner that they are located exclusively in an annular space between the flange  50  and a counter toothing of the external toothing of the eccentric gear  26 . 
         [0049]    The bearing bushes  39  and  40  are located between the collar  32  and the wedge segments  36 . The bearing bush  41  is located between the wedge segments  36  and the eccentric hole  30 . Preferably, at least one of the bearing bushes is formed in a slotted manner; it therefore does not constitute a closed ring. This preferably applies to the bearing bush  39 . The latter sits, preferably secured against rotation, on the collar  32  of the first fitting part  20 . This can be achieved by the collar  32  being provided with a rotation-blocking device. A rotation-blocking device is, for example, a projection which protrudes radially outwards from the collar  32 , or an impression in the collar  32 . This rotation-blocking device can be produced, for example, during the manufacture of the collar formation, or it may be formed later. The rotation-blocking device engages the slot of the bearing bush  39 . The bearing bush  39  carries a slide coating on the outer circumference; this may be, for example, a plastic coating, in particular Teflon, or a metal coating. The further, non-slotted outer bearing bush  40  is placed on the outer circumference of the slotted bearing bush  39 . It envelops the slotted bearing bush  39 . This outer bearing bush  40  is preferably made from steel; it preferably does not comprise a sliding layer. The wedge segments  36  abut with their inner surfaces against the outer bearing bush  40 , the inner surfaces are defined by an internal radius. The internal radius of the wedge segments  36  is slightly larger, preferably 5% to 20% larger than the external radius of the outer bearing bush  40 . This causes a line contact between the wedge segments and the outer bearing bush  40 ; in any case, there will be no surface abutment. In this case, the conditions with regard to friction are such that there is a frictional grip between the inner surface of the wedge segments  36  and the outer jacket of the outer bearing bush  40  during actuation, and that these friction partners together slide on the slide-coated outer jacket of the slotted bearing bush  39 . Actuation is initiated by means of the control part  34  with its two control flanks, which are opposite from the narrow sides of the wedge segments  36 . Depending on the direction of rotation, one of the two control flanks comes into engagement with a narrow side of an adjacent wedge segment  36 . In an alternative, the collar  32  and the slotted bearing bush  39  constitute a single part, preferably, no separate bearing bush  39  is provided; rather, the collar  32  itself is provided with a slide coating. The construction described above in this paragraph can also be realized independently from the characterizing features of claim  1 ; in any case, not all features of claim  1  are required. 
         [0050]    The third exemplary embodiment according to the  FIGS. 7 and 8  also largely corresponds to the exemplary embodiment discussed so far. The differences are discussed below. 
         [0051]    Whereas the latching tooth  64  is configured to be pointed in the first two embodiments, it is now configured to be wider; it has a trough-shape. It does not have a tip. It has a projection with a width of at least 1 mm. 
         [0052]    In the first two exemplary embodiments, the latching part  60  is released by being entrained on a lower contour  66 . This release is now at a different location. It has been rearranged by 90° in both directions of rotation. The blocking part  60  now has one cam  68 , respectively, which protrudes radially outward from the blocking part  60  and is offset by about 90° relative to the lower contour  66 . The two cams  68  are disposed relative to each other at an angle of between 150° and 210°, preferably about 180°. A counter-cam  70  for each of the two cams  68  is provided on the drive part  24 . The angular position is such that, when the one cam  68  abuts against its adjacent counter cam  70 , the other cam  68  has a distance from its adjacent counter cam  70  of between 10° to 40°, in particular 25° to 35°. The two counter cams  70  are disposed relative to each other at an angle of between 120° and 180°, preferably about 150°. 
         [0053]    As may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, numerous changes and modifications may be made to the above-described and other embodiments of the present invention without departing from the spirit of the invention as defined in the claims. For example, the components of the apparatus may be made of any of numerous different materials that are currently known, or that later become known for performing the function(s) of each such component. Similarly, the components of the apparatus may take any of numerous different shapes and/or configurations, additional components may be added, components may be combined, and one or more components or features may be removed.