Abstract:
An actuator ( 10, 210 ) for a motor vehicle, in particular a motor vehicle seat, includes an electric motor ( 20 ) that is equipped with an output shaft ( 24 ) and a gear mechanism ( 100, 200 ) that is connected to the output shaft ( 24 ). The gear mechanism ( 100, 200 ) is provided with a gear mechanism housing ( 120, 220 ). A gear mechanism retaining device ( 160, 260 ) supports the gear mechanism housing ( 120, 220 ) in such a way that the housing can swivel about a swivel axis ( 165, 265 ). A shaft section ( 126, 226 ) of the gear mechanism housing ( 120, 220 ) that is flush with the swivel axis ( 165, 265 ) is surrounded at least in part by a retaining bracket ( 170, 270 ) of the gear mechanism retaining device ( 160, 260 ). The output shaft ( 24 ) is located outside the retaining bracket ( 170, 270 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Phase Application of International Application PCT/EP2015/051467 filed Jan. 26, 2015 and claims the benefit of priority under 35 U.S.C. §119 of German Application 10 2014 201 742.4 filed Jan. 31, 2014, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to an actuating drive for a motor vehicle, in particular for a motor vehicle seat, having an electric motor which has an output shaft, a gear mechanism which is connected to the output shaft and which has a gear housing, and having a gear retention device which supports the gear housing pivotably about a pivot axis, wherein a shaft portion of the gear housing in alignment with the pivot axis is at least partially surrounded by a curved retention member of the gear retention device. 
       BACKGROUND OF THE INVENTION 
       [0003]    DE 10 2006 005 499 A1 discloses an actuating drive in which a gear retention member completely surrounds a gear housing so that an output shaft of an electric motor is also enclosed by the gear retention member. The gear housing is supported in the gear retention member in a rotatable manner so that fitting imprecisions and tolerances are compensated for by a relative rotation between the gear housing and the gear retention member. 
         [0004]    DE 10 2008 017 017 A1 discloses an actuating drive whose gear housing is supported in a retention member, wherein a pivot bearing is provided between the gear housing and the retention member and a support which is opposite the pivot bearing is provided between the gear housing and the retention member. The retention member substantially surrounds the gear housing and an output shaft of an electric motor extends inside the retention member. 
         [0005]    CH 647 305 A5 discloses a motor-driven linear thrust device having a connecting rod which can be driven by means of a screw spindle having a nut, wherein both the nut and the screw spindle are rotatably supported individually and have an individual drive. The linear thrust device has a housing which comprises two journals in order to be able to support the linear thrust device in a pivotable manner. 
       SUMMARY OF THE INVENTION 
       [0006]    An object of the invention is to improve an actuating drive of the type mentioned in the introduction, in particular to provide a cost-effective gear retention device which is optimized in terms of structural space. 
         [0007]    This object is achieved according to the invention by an actuating drive having an electric motor which has an output shaft, a gear mechanism which is connected to the output shaft and which has a gear housing, and having a gear retention device which supports the gear housing pivotably about a pivot axis, wherein a shaft portion of the gear housing in alignment with the pivot axis is at least partially surrounded by a curved retention member of the gear retention device. According to the invention, the output shaft is arranged outside the curved retention member. 
         [0008]    In that the output shaft is arranged outside the curved retention member, the curved retention member does not completely surround the gear housing so that structural space for the curved retention member is not required at the side of the output shaft facing away from the curved retention member. There is thereby provided a cost-effective gear retention device which is optimized in terms of structural space. 
         [0009]    Advantageous embodiments which can be used individually or in combination with each other are set out in the dependent claims. 
         [0010]    The gear retention device can be used in all actuating drives which are known per se and in which a pivot movement between the gear retention device and the gear mechanism is advantageous. There may also be used electric motors which have an integrated or fitted reduction gear and which are connected to an additional gear mechanism. In this instance, the term “output shaft of the electric motor” is intended to be understood to refer to an output shaft of the integrated or fitted reduction gear. The actuating drive advantageously has precisely one electric motor. 
         [0011]    It is particularly advantageous to have an actuating drive according to the invention having a spindle nut which can be driven at least indirectly by the output shaft and which is rotatably supported in the gear housing, and wherein the spindle nut cooperates with a spindle in such a manner that a rotation of the spindle nut results in a relative displacement between the spindle and the gear housing. The moving spindle can actuate, for example, a seat adjuster or a window lifting mechanism in a motor vehicle. 
         [0012]    It is possible to achieve a spindle length which is minimized for a predetermined adjustment range of the actuating drive and a more pleasant end stop noise by there being provided in at least one end region of the spindle a spindle stop which projects radially from the spindle and which abuts an end face of the spindle nut in an end position of the adjustment range of the actuating drive and thereby defines the end position. 
         [0013]    A spindle stop having a portion which comprises plastics material or rubber and which abuts the end face of the spindle nut further improves the stop noise behavior of the actuating drive. 
         [0014]    A gear retention device which is particularly optimized in terms of structural space can be obtained by the shaft portion at least partially adjoining a through-opening of the gear housing or projecting into a through-opening of the gear housing, and the curved retention member extending through that through-opening. The curved retention member can thus surround and support the shaft portion or form at least a portion of a bearing location. 
         [0015]    The shaft portion and with it the pivot axis of the gear retention device are preferably arranged so as to be offset in a radial direction relative to the output shaft. The output shaft can thereby be arranged in a space-saving manner outside the curved retention member. The pivot axis and the output shaft preferably extend in a mutually parallel but offset manner. 
         [0016]    The curved retention member preferably comprises precisely two U-shaped curved members each having a first bearing shell which form two peripheral hubs for supporting two shaft portions together with a second bearing shell of a closure member. In this instance, the closure member closes the curved retention member in such a manner that each shaft portion is completely surrounded in the peripheral direction thereof by the gear retention device. 
         [0017]    The gear retention device may have one, two or more bearing locations for the gear mechanism. The curved retention member comprises a first bearing shell for each of the bearing locations. A plurality of first bearing locations can also merge one in the other. The closure member comprises a second bearing shell for each of the bearing locations. A first bearing shell and the second bearing shell complement each other to form a hub which supports the respective shaft portion by the angular ranges of the two bearing shells complementing each other to form a peripheral cylinder. For example, the first bearing shell and the second bearing shell are constructed as half-cylinders which surround the pivot axis through 180°, respectively. 
         [0018]    A particularly simple assembly of the gear retention device on the shaft portions of the gear housing can be achieved by the closure member being connected to the curved retention member by means of a clip-fit connection. In this instance, resilient arms having projections are preferably formed on the closure member. The projections spring back during the assembly of the gear retention device in recesses of the curved retention member and thus ensure a positive-locking connection counter to the joining direction which is advantageously substantially parallel with the spindle. 
         [0019]    The closure member can alternatively, or additionally to the clip-fit connection, be connected to the curved retention member in a positive-locking manner in a direction parallel with the pivot axis. To this end, at least one insertion profile of the curved retention member can engage in a complementarily formed closure member opening. 
         [0020]    In order to connect the actuating drive to an additional component, for example, a seat structure, the gear retention device has at least one opening for the introduction of a fixing means, in particular a screw or a rivet. A center axis of the fixing means orientated in the longitudinal direction of the fixing means preferably extends parallel with the spindle. The fixing means is thereby loaded to a comparatively small extent. In contrast to the actuating devices known from the prior art, the gear retention device and the fixing means are loaded with respect to pressure to a lesser extent. 
         [0021]    The shaft portions can also be constructed as journals which project laterally from the gear housing. The shaft portions can be constructed integrally with the gear housing, for example, injection molded, or be fixed to the gear housing. 
         [0022]    The actuating drive according to the invention provides optimization of the stability with respect to the prior art, whereby the noise behavior, the degree of efficiency and the wear resistance are optimized. 
         [0023]    The invention is explained in greater detail below with reference to two advantageous embodiments which are illustrated in the figures. However, the invention is not limited to those embodiments. 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 
         [0024]    In the drawings: 
           [0025]      FIG. 1  is a perspective view of a first embodiment of an actuating drive according to the invention in a first end position of the spindle; 
           [0026]      FIG. 2  is a view corresponding to  FIG. 1  with a partially sectioned gear housing; 
           [0027]      FIG. 3  is a perspective view of the actuating drive from  FIG. 1  in a second end position of the spindle; 
           [0028]      FIG. 4  is a view corresponding to  FIG. 3  with a partially sectioned gear housing; 
           [0029]      FIG. 5  is a perspective view of the actuating drive from  FIG. 1  without a gear retention device; 
           [0030]      FIG. 6  is a detailed view from  FIG. 1  of the region of the gear retention device; 
           [0031]      FIG. 7  is an exploded view of the gear retention device from  FIG. 1 ; 
           [0032]      FIG. 8  is a sectioned view of the actuating drive from  FIG. 1  in the region of the gear retention device; 
           [0033]      FIG. 9  is a sectioned view similar to  FIG. 8 ; 
           [0034]      FIG. 10  is a perspective view of a second embodiment of an actuating drive according to the invention; 
           [0035]      FIG. 11  is a view corresponding to  FIG. 10  with a partially sectioned gear housing of the second embodiment; and 
           [0036]      FIG. 12  is a view corresponding to  FIG. 10  with an exploded view of the gear retention device of the second embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0037]    Referring to the drawings,  FIGS. 1 to 9  illustrate a first embodiment of an actuating drive  10  for a motor vehicle, in particular for a motor vehicle seat. The actuating drive  10  comprises an electric motor  20 , a gear mechanism  100  connected to the electric motor  20  and a gear retention device  160 . 
         [0038]    The electric motor  20  comprises an output shaft  24  which is connected in a rotationally secure manner to an endless screw  130  of the gear mechanism  100 . The endless screw  130  is in engagement with a spindle nut  140 . The spindle nut  140  is part of the gear mechanism  100  and is in engagement with a spindle  150  in a manner known per se. 
         [0039]    The gear mechanism  100  comprises a gear housing  120  which receives the endless screw  130  and the spindle nut  140  therein. To this end, the gear housing  120  has a substantially cylindrical region for receiving the endless screw  130  and an additional, substantially cylindrical region for receiving the spindle nut  140 , which region is orientated in the direction of the spindle  150  and perpendicularly to the cylindrical receiving region for the endless screw  130 . 
         [0040]    The gear retention device  160  supports the gear housing  120  pivotably about a pivot axis  165 . The gear retention device  160  may be fixed, for example, to a vehicle seat structure of the motor vehicle seat. 
         [0041]    The spindle  150  extends through the gear housing  120 . To this end, the gear housing  120  has a first housing opening  121  and a second housing opening  122 , through which the spindle  150  extends. A bearing bush  128  for supporting a first of two ends of the spindle nut  140  is inserted into the second housing opening  122 . A second end of the spindle nut  140  is supported directly in the gear housing  120 . The spindle  150  also extends through the bearing bush  128 . 
         [0042]    The gear housing  120  has two through-openings  124 . When viewed in the direction of the pivot axis  165 , beside the second housing opening  122 , the substantially cylindrical region of the gear housing  120  which receives the spindle nut  140  is widened in two diametrically opposing regions and provided with a through-opening  124 . The two through-openings  124  are slot-like, wherein the longitudinal axes of the slots extending in the direction of the greatest clear width of the through-openings  124  extend parallel with a center axis of the spindle  150 . 
         [0043]    In a region of the through-opening  124  facing away from the endless screw  130 , the gear housing  120  and the inner walls of the through-openings  124  are formed in such a manner that each through-opening  124  is delimited by a shaft portion  126  having a circular cross-section. The two shaft portions  126  define the pivot axis  165 , about which the gear housing  120  can be pivoted relative to the gear retention device  160 . Fitting imprecisions and tolerances within the actuating drive  10  and/or positional tolerances of the actuating drive  10  can thereby be compensated for relative to a component which is intended to be driven. Many components which are intended to be driven, such as, for example, four-bar height adjusters, may further require in principle that the actuating drive  10  has a limited ability to rotate. 
         [0044]    The gear retention device  160  comprises a curved retention member  170  and a closure member  180  which are connected, in this case clip-fitted, to each other, and which receive the two shaft portions  126  of the gear housing  120  in a supporting manner between them. During the assembly process, the spindle nut  140  and subsequently the bearing bush  128  are introduced through the second housing opening  122  into the gear housing  120 . Subsequently, the gear retention device  160  can be fitted to the gear housing  120 . 
         [0045]    The curved retention member  170  comprises two U-shaped curved members  174  which are arranged so as to be offset relative to each other in the direction of the pivot axis  165  and which are connected to each other by means of a web  176 . Each of the two U-shaped curved members  174  comprises a profiled portion which is curved in a semi-circular manner and each of the two ends of which a linear insertion profile  175  adjoins. A first bearing shell  171  which extends over an angle of approximately 180° in a semi-cylindrical manner about the pivot axis  165  is formed in the inner periphery of the profiled portion which is curved in a semi-circular manner. 
         [0046]    Each of the two U-shaped curved members  174  has two curved retention member openings  172  which extend parallel with the spindle  150 . The outer sides of the two U-shaped curved members  174  each have a notch-like recess  179  which is a component of a clip-fit connection described in greater detail below. 
         [0047]    The closure member  180  has a substantially planar, rectangular basic geometry, through the center of which a first closure member opening  181  extends. The first closure member opening  181  is constructed in a slot-like manner, wherein the longitudinal axis of the slot extends perpendicularly to the pivot axis  165  and acts as a through-hole for the spindle  150 , which longitudinal axis extends in the direction of the largest clear width of the first closure member opening  181 . 
         [0048]    A second closure member opening  182  is arranged in the four corner regions of the closure member  180 , respectively. In the direction of the material thickness of the closure member  180 , at least one, in this instance every other, closure member opening  182  is subdivided by a step-like shoulder  183  into two portions. A first portion is facing the pivot axis  165  and has a cross-section which is complementary to the insertion profile  175  of the U-shaped curved member  174 . A second portion of the second closure member opening  182  facing away from the pivot axis  165  has a diameter which is smaller than the largest extent of the cross-section of the insertion profile  175 . 
         [0049]    Two semi-cylindrical second bearing shells  185  extend in the direction of the pivot axis  165  and form together with one of the first bearing shells  171  of the curved retention member  170  a peripheral hub which supports one of the two shaft portions  126  rotatably therein. 
         [0050]    A resilient arm  188 , which extends perpendicularly to the planar basic geometry of the closure member  180  and in the direction of the curved retention member  170 , is arranged in the four corner regions of the closure member  180 . A projection  189  is attached to the self-supporting end of each resilient arm  188 . The projections  189  engage in the recesses  179  of the curved retention member  170  so that the previously mentioned clip-fit connection which is known per se and which comprises the resilient arm  188 , projection  189  and recess  179  is provided. 
         [0051]    The insertion profiles  175  of the curved retention member  170  are inserted in the second closure member openings  182  of the closure member  180  so that the closure member  180  is connected to the curved retention member  170  in a positive-locking manner in a direction parallel with the pivot axis  165 . 
         [0052]    The second closure member openings  182  are each aligned with one of the curved retention member openings  172 . Fixing means, in particular screws, which are not illustrated in the figures extend through the curved retention member openings  172  and the second closure member openings  182 , serve to fix the gear retention device  160  and further secure the connection, in the assembled state, between the curved retention member  170  and the closure member  180  of the gear retention device  160 . The center axes of the fixing means extend parallel with each other and substantially parallel with the spindle  150 . 
         [0053]    The output shaft  24  is arranged completely outside the gear retention device  160 . 
         [0054]    The actuating drive  10  can be adjusted between a first end position of the spindle  150  and a second end position of the spindle  150 . The end positions are defined by stops. 
         [0055]    The first end position is reached when a first spindle stop  151  which is fixedly connected to the spindle  150  moves from the outer side against a region of the gear housing  120  surrounding the first housing opening  121 . The second end position is reached in the opposite direction when a second spindle stop  152  which is fixedly connected to the spindle  150  has traveled through the first closure member opening  181  and the bearing bush  128  and moves against an end face of the spindle nut  140  facing the second spindle stop  152 . 
         [0056]    The first spindle stop  151  is a circular disk whose outer diameter is greater than the inner diameter of the first housing opening  121 . 
         [0057]    The second spindle stop  152  is a circular disk whose outer diameter is smaller than the inner diameter of the second housing opening  122 , smaller than the inner diameter of the first closure member opening  181  and slightly smaller than the inner diameter of the bearing bush  128 . The second spindle stop  152  can thereby travel through the first closure member opening  181  and the bearing bush  128  and does not move against one of those components. This reduces the necessary length of the spindle  150 . 
         [0058]    In this instance, the second spindle stop  152  comprises different material in two disk-like portions. A region facing the spindle nut  140  comprises a plastics material or rubber material. A region facing away from the spindle nut  140  comprises a metal material, in particular steel. 
         [0059]      FIGS. 10 to 12  illustrate a second embodiment of an actuating drive  210 . The actuating drive  210  comprises a gear mechanism  200  which differs from the gear mechanism  100  of the first embodiment as a result of a gear housing  220  which is modified in terms of individual details. A gear retention device  260  further differs from the gear retention device  160  of the first embodiment. Components of the actuating drive  210  which are modified with respect to the first embodiment have reference numerals increased by 100. Unless described otherwise below, the second embodiment corresponds to the first embodiment. 
         [0060]    The actuating drive  210  comprises an electric motor  20  and the gear mechanism  200  which is connected to the electric motor  20  and whose gear housing  220  is supported by a gear retention device  260  pivotably about a pivot axis  265 . 
         [0061]    Two shaft portions  226 , which project laterally from the gear housing  220  at both sides and perpendicularly to a spindle  150  which extends through the gear housing  220 , are formed on the gear housing  220 . The two shaft portions  226  define a pivot axis  265  about which the gear housing  220  can be pivoted relative to the gear retention device  260 . The two shaft portions each have a circular cross-section which has a planar flattened portion at one location. 
         [0062]    The gear retention device  260  comprises a curved retention member  270  and a closure member  280  which are connected, for example, clip-fitted, to each other and which receive the two shaft portions  226  of the gear housing  220  in a supporting manner between them. 
         [0063]    The curved retention member  270  is constructed in the manner of a U-shaped curved member whose legs extend substantially perpendicularly to the spindle  150 . In an inner region between the legs of the curved retention member  270  there is formed a first bearing shell  271  which extends over an angle of approximately 180° in a semi-circular manner about the pivot axis  265 . 
         [0064]    The closure member  280  also has a U-shaped basic form having two legs, wherein the legs of the closure member  280  extend substantially parallel with the spindle  150 . Each of the two legs of the closure member  280  laterally has a second semi-cylindrical bearing shell  285 . 
         [0065]    The length of the legs of the closure member  280  corresponds to the spacing of the legs of the curved retention member  270 . The legs of the curved retention member  270  receive the closure member  280  between them. The two semi-cylindrical second bearing shells  285  form, together with the first bearing shell  271  of the curved retention member  270 , a peripheral projection which rotatably supports one of the two shaft portions  226  therein. 
         [0066]    The curved retention member  270  has in the region of the leg ends a plurality of through-holes which are not illustrated in the figures. Those through-holes serve to fix the curved retention member  270  to a structural member, for example, a seat structure. The center axes of the fixing means each extend substantially perpendicularly to the spindle  150 . 
         [0067]    The output shaft  24  is completely arranged outside the gear retention device  260 . 
         [0068]    The features disclosed in the above description, the claims and the drawings may be significant both individually and in combination for the implementation of the invention in the various embodiments thereof. 
         [0069]    While specific embodiments of the invention have been shown and 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.