Abstract:
An electric-motor adjustment drive is provided for an adjustment element in a motor vehicle, in particular a window lifter, that has a drive module, which includes a pole pot that supports a motor shaft, and having an electronic module having a circuit board, which can be inserted into a housing of a brush holder, which housing is connected to the drive module. The circuit board is retained in an insertion plane perpendicular to the motor shaft by the housing of the brush holder in a form- and/or force-closed manner, wherein a number of contact elements for motor contacting and/or for interference suppression are arranged in the housing, which contact elements are contacted within the housing when the circuit board is inserted.

Description:
This nonprovisional application is a continuation of International Application No. PCT/EP2010/002770, which was filed on May 6, 2010, and which claims priority to German Patent Application No. DE 20 2009 008 646.1, which was filed in Germany on Jun. 22, 2009, and which are both herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an electromotive adjustment drive for an adjustment element in a motor vehicle. An adjustment drive in this context can be understood to be, for example, a sunroof drive, a door drive, a rear door drive, a seat adjustment drive or a window lifter drive. 
     2. Description of the Background Art 
     A electromotive adjustment drive usually includes a drive module, which, in turn, may be composed of a motor module and a gear module, as well as an electronic module. The drive module includes an electric motor whose armature (rotor), which is mounted on a motor shaft, is rotationally supported in a pole pot in which permanent magnets are held in a bipole or multipole arrangement. The motor shaft protruding from the pole pot is guided into a gear housing having a worm gear, for example via a brush holder. An electronic module having a printed circuit board may be positioned on the gear housing in the manner of an interface. In this case, a mechanical connection is usually established between the electronic module and the gear housing, and the printed circuit board is also usually electrically contacted with motor contacts, which, in turn, are connected to carbon brushes of the electric motor, which is conventionally designed as a commutator motor. 
     For example, an electromotive window lifter drive, which has a modular design of the type described above, is known from DE 101 08 414 B4. The drive module, which includes the motor module and the gear module, is always the same, while the electronic module has different designs and which, in its diversity, may be provided with a modular configuration. The interface to the drive module is always the same, while the electronic module may be designed as a simple plug-in contact (power on/off) or as comparatively complex electronics. A distinction may also be made between positioning in a wet area and a dry area. 
     Due to the increasing number of electronic components for implementing different functions, the electromagnetic compatibility requirements are also higher. Interference must be avoided as reliably as possible, but at least dampened as effectively as possible. Any additional components needed for this purpose, for example coils (chokes) or capacitors, require additional installation space. In addition, it is desirable to integrate sensor electronics in the form of Hall sensors and a corresponding evaluation unit into the electronics or the electronic module. 
     To accommodate interference suppression electronics of this type in as little space as possible, it is known from DE 103 18 734 A1 to provide a separate printed circuit board which is inserted into the brush holder and is contacted via spring contacts. 
     A special clamping contact is furthermore known from DE 10 2005 055 740 A1, in which an electrical conductor, which, in turn, is designed as a spring contact, rests against a contact surface (contact pad) of the printed circuit board and is clamp-contacted with the pole pot for connecting to ground. The printed circuit board itself is, in turn, inserted into the gear or brush holder housing in a retaining groove provided in the housing base. The printed circuit board is held on a connector of the slide-in module. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide an electromotive adjustment drive which has a particularly space-saving design with regard to the electronics and/or interference suppression. 
     The electromotive adjustment drive, in an embodiment, includes a brush holder whose housing has a plurality of contact elements, preferably for both contacting the motor and for interference suppression. Two contact elements are usually provided for contacting the motor, while a further contact element is provided for interference suppression, this additional contact element establishing an electrically conductive connection (ground connection) between the printed circuit board and the pole housing, for which purpose the pole housing is mounted on the housing of the brush holder. A flange-like housing collar of the brush holder housing serves as a stop for the pole pot, which is mounted on a holding shoulder of the brush holder housing. 
     The printed circuit board of an electronic module may be suitably inserted into at least one U-shaped insertion slot on an insertion plane perpendicular to the motor shaft, in particular it may be inserted by its end face facing the motor shaft. The motor shaft, which carries the rotor of the electric motor and which is supported in the pole pot, is guided out of the brush holder housing via the brush holder. 
     In a particularly suitable manner, the printed circuit board can be held in the housing, i.e., in the insertion slot or in each insertion slot provided therein, not only in a form-locked manner but also in a force-fit manner. A clamping tab, which is preferably molded onto the housing and is suitably elastically (or plastically) deformed while the printed circuit board is being inserted into the housing, is used for this purpose, thus ensuring a reliable clamping attachment between the printed circuit board and the housing. Two insertion slots as well as one clamping tab each are suitably provided upstream therefrom. These elements are suitably situated opposite each other on a circumferential housing edge on an underside of the housing facing away from the pol pot. 
     The insertion or holding slots may be designed to accommodate the printed circuit board from the direction of insertion as L-shaped housing moldings. The moldings project from the plane of the circumferential housing edge in the axial direction. However, the housing moldings are preferably T-shaped, thus forming diametrically opposed insertion slots. This makes it possible to insert a printed circuit board in the direction of insertion as well as counter to the direction of insertion (insertion counter-direction). This, in turn, particularly advantageously provides different designs of contacting or contact elements. Thus, the contact elements for a printed circuit board inserted in the insertion direction may be designed as spring contacts which are then clamp-contacted with contact surfaces (contact pads) provided on the printed circuit board. Alternatively, a classic blade contact, knife contact or clamping contact may preferably also be provided, which is then used to establish a corresponding contact with a printed circuit board inserted from the insertion counter-direction. 
     The contact elements, which can be designed as spring contacts, are suitably bent, stamped sheet metal parts. The actual contact arm having the contact end on the free end is bent at an obtuse angle from a holding arm with which the spring element is inserted into a longitudinal groove which is introduced into the housing of the brush holder and extends in the axial direction. 
     An interference suppression contact of a similar design suitably has a raised contact tab on the free end of the holding arm, so that a clamping contact between this interference suppression spring contact and the pole housing, i.e., its inner wall, is reliably established when the pole pot is mounted on a corresponding shoulder contour of the housing. A corresponding groove, in which the holding arm of this anti-interference spring contact lies, is then open to the outside at least in the area of the shoulder contour of the brush holder housing which extends from the housing collar toward the pole pot. 
     Hall sensors, which are mounted on the printed circuit board in the form of a Hall IC, are preferably provided for a suitable sensor system which is used to detect the rotational direction and/or speed of the motor, in particular for the purpose of determining the position of the adjustment element operated by the adjustment drive, for example a window pane. A ring magnet, which rests on the motor shaft and rotates therewith, is used as the transducer. The ring magnet, which has a plurality of magnetic poles (north and south poles), may be advantageously situated particularly close to the printed circuit board, due to the reliable attachment of the printed circuit board to the brush holder housing and, at that location, suitably directly to the underside of its housing. This saves a substantial amount of space, since only minimal production-related deviations and tolerances are to be expected in this design embodiment of the adjustment drive according to the invention, and a comparatively small distance may therefore be allowed between the ring magnet and the printed circuit board. 
     In a particularly advantageous embodiment, only the part or board section of the printed circuit board which is covered by the brush holder housing is subjected to the unavoidable carbon abrasion of the brushes. The remaining board section, which is located outside the brush housing and is therefore not covered thereby, is protected against this carbon dust. This effect is achieved by the fact that the lower housing edge of the brush holder housing which faces away from the pole pot and faces toward the printed circuit board forms only an extremely small gap with the surface of the printed circuit board facing the lower housing edge. Even this small gap results in a reliably tight seal between the housing and the printed circuit board. 
     To optimize the sealing function, an additional sealing element in the form of a rubber or plastic seal may be provided in the area of the lower housing edge. When the printed circuit board is inserted into the insertion slot, the seal yields in the direction of the housing interior in the manner of a sealing lip and is thus pressed tightly against the surface of the printed circuit board. 
     The advantages achieved by the invention are, in particular, the fact that both a reliable attachment and a precise positioning of the printed circuit board are ensured, due to a form-locked and force-fit holding of the printed circuit board of an electromotive adjustment drive, which is inserted into a corresponding housing of a brush holder. The reliable attachment suitably offers the opportunity to avoid attaching the printed circuit board or to only comparatively slightly attach the printed circuit board in the electronic module (for example also in an electronic housing), where it would otherwise be additionally attached. The positioning accuracy suitably offers the opportunity to construct a particularly compact sensor system for the motor speed and/or direction of rotation and to provide, in particular, a printed circuit board which carries a ring magnet at a distance from the sensor which has up to now not been possible in practical terms, along with an evaluation electronic system for evaluating and/or preprocessing the sensor signals. 
     The reliable clamping attachment of the printed circuit board to the brush holder housing is suitably provided by clamping elements molded on the housing in the form of web-like clamping tabs which have been worked from the housing material. These clamping tabs are thus elastic in a particularly easy manner and thus have a spring effect which establishes a friction fit or a force fit. 
     One aspect which is independent of this clamping attachment is the easily produced sealing effect between the brush holder housing and the printed circuit board. This is due to the fact that the insertion, fixing, and/or guide elements for the printed circuit board are situated on the underside of the housing of the brush holder in such a way that the printed circuit board partially seals the brush holder housing on the bottom. In other words, the housing wall of the brush holder housing practically reaches as far as the printed circuit board, so that, to this extent, a nearly adequate sealing effect is achieved against the unavoidable carbon dust of the brushes. An additional sealing lip may be easily integrated into the housing. 
     This sealing effect, including the protection of the printed circuit board section running outside the brush holder housing against carbon dust even without the additional force-fit printed circuit board attachment and/or the particularly variable and flexible contacting in the direction of insertion and against the direction of insertion is viewed as an independent invention. 
     The aspect of contacting the printed circuit board both in the conventional manner with the aid of conductor or clamping contacts as well as with the aid of spring contacts which are contacted with contact surfaces (pads) on the printed circuit board is, in turn, also viewed as an independent invention, independently of the sealing functionality as well as of the clamping attachment with the aid of the clamping element which is also referred to below as the clamping eye. This approach provides a particularly flexible brush holder in which the relevant contacting variant is achieved only by inserting the printed circuit board in one direction of insertion or another. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG. 1  shows a perspective representation of an electromotive adjustment drive having a drive module and an electronic module; 
         FIG. 2  shows a perspective representation of the interface, designed as a mechanical clamping attachment, between a brush holder of the drive module and a printed circuit board of the electronic module; 
         FIG. 3  shows the clamping area between the printed circuit board and the brush holder housing in the area of a clamping eye on a larger scale; 
         FIG. 4  shows the electrical interface between spring contacts and the printed circuit board as well as the situating of a ring magnet opposite a sensor system on the printed circuit board; 
         FIG. 5  shows a perspective representation of the brush holder having a mounted pole housing in an oblique view of the housing underside of the brush holder; 
         FIG. 6  shows a perspective side view of a curved housing side of the brush holder, including contact elements inserted therein; 
         FIG. 7  shows a schematic perspective representation of the situation of the bent spring contacts relative to the printed circuit board; 
         FIG. 8  shows the spring contacts according to  FIG. 7  in the form of motor and interference suppression contacts in their embodiment as stamped sheet-metal parts; 
         FIG. 9  shows the brush holder in a perspective view from below of the housing underside, including the circumferential housing edge; 
         FIG. 10  shows a perspective representation of the lower housing area of the brush holder, with the printed circuit board inserted and clamp-contacted; and 
         FIG. 11  shows the brush holder according to  FIG. 10  in a perspective partial view, including the bifurcated contact of the clamping contact on the printed circuit board side. 
     
    
    
     DETAILED DESCRIPTION 
     Corresponding parts are provided with the same reference numerals in all figures. 
       FIG. 1  shows an electronic adjustment drive  1  comprising a drive module  2  and comprising an electronic module  3 . Drive module  2  includes a motor module having a pole pot  4  and a gear module  5 . Gear module  5  includes a worm gear, which is not illustrated in further detail, which has a worm wheel which engages with a worm situated on a motor shaft. In the exemplary embodiment, the connection between pole pot  4  and gear housing  6  is a screw connection  7 . 
     As may be seen comparatively clearly from  FIG. 2 , a brush holder  9  having a brush housing  10  is situated in the area of this screw connection  7 , in which pole pot  4  is screwed to gear housing  6  with the aid of, for example, four screws  8 . A printed circuit board  11 , which is assigned to electronic module  3  and which is equipped with electronic components of the SMD type (surface-mounted devices), is inserted into this housing  10  of brush holder  9  on the underside of the housing. Printed circuit board  11  is inserted in a form-locked manner into a U-shaped insertion slot  12  of brush holder housing  10 . A clamping eye  13  having a clamping tab  14  in brush holder housing  10  establishes a force-fit, elastic clamping connection between printed circuit board  11  and brush holder housing  10 . 
       FIG. 3  shows the area of the clamping connection between printed circuit board  11 , which is inserted into U-shaped insertion slot  12 , and brush holder housing  10 . Clamping eye  13  is formed by a recess or through-opening  15  in housing wall  16  of housing  10 . A relatively narrow edge or housing web  18 , which forms the outside of clamping tab  14 , is provided on housing underside  17  of brush holder housing  10 , due to recess  15 . This housing web is situated upstream from U-shaped clamping slot  12  in insertion direction  19  or in counter-direction (insertion counter-direction)  20 , which is also illustrated in  FIG. 3 . 
     A printed circuit board  11 , which is inserted in counter-direction  20  in a manner which is not illustrated in greater detail, is also accommodated by a U-shaped insertion slot  12  and clamped in place in a form-locked and force-fit manner by clamping tab  14 , which, in turn, forms a clamping eye  13 . 
     The two anti-parallel, U-shaped insertion slots  12  are formed by a T-shaped housing molding  21 , which extends on housing underside  17  in axial direction  22 . A motor shaft  23 , which is illustrated in  FIGS. 2 through 4  and which is supported on axial and/or radial bearing  24  ( FIG. 1 ) within pole pot  4 , runs in axial direction  22  and extends beyond brush holder  9  into gear housing  6  of gear module  5 . A ring magnet  25  is nonrotationally connected to motor shaft  23 . This magnet is situated on board underside  26  of printed circuit board  11  facing away from pole pot  4  at (an ideally short) distance a ( FIG. 4 ). 
       FIGS. 5 and 6  each show a perspective representation of brush holder  9 , together with its housing  10 , including and excluding a mounted pole pot  4 . It is apparent that two insertion slots  12  for printed circuit board  11  are each provided in both insertion direction  19  and in counter-direction  20 . An inclined ramp  28  is provided on U-shaped arm  27  facing away from housing underside  17  as an insertion aid for printed circuit board  11 . This U-shaped arm  27 , which is spaced a distance equal to the clear width between insertion slot  12  and housing underside  17 , is thus an integral part of housing molding  21 . The U-shaped arm of insertion slot  12 , which is situated opposite this U-shaped arm  27 , is formed by a circumferential housing edge  29  on housing underside  17  of brush holder housing  10 . Housing edge  29  on the underside of the housing is at least approximately continuously circumferential. 
     It is apparent that clamping tab  14  provided by clamping eye  13  is situated at a distance from slot or groove bottom  30  of particular insertion slot  12  in insertion direction and counter-direction  19 ,  20 . Clamping tab  14  is not covered by U-shaped arm  27  opposite housing edge  29  (cover-fee) and is therefore situated upstream from insertion slot  12  in insertion direction  19  and counter-direction  20 . 
     Like pole pot  4 , housing  10  of brush holder  9  has an oval cross-sectional shape with two diametrically opposed curved or arc-shaped housing sides  10   a ,  10   b  and two flat sides  10   c ,  10   d . Three spring contacts  31  and  32  are held in or on housing wall  16  in housing  10  of brush holder  9  in the area of one of the two curved housing sides  10   a , namely the housing side facing insertion direction  19  in the exemplary embodiment. Spring contacts  31  represent motor contacts which are connected to carbon brushes  33  in brush holder  9 . These carbon brushes, in turn, are connected to an interference suppression choke  35  via a conductor wire  34 , the interference suppression choke being mounted on a holding mandrel  36  within brush holder  9 . One interference suppression choke  35  is suitably assigned to each of the two brushes  33  ( FIG. 9 ). 
     As is comparatively clearly apparent from  FIG. 6 , spring contact  32  acting as an interference suppression contact is introduced into a housing groove  37  in housing wall  10   a  which is at least partially open to the outside. A positioning and embodiment of a spring contact  32  of this type are also used in a corresponding housing groove  37  on diametrically opposed curved housing side  10   b  of brush holder housing  10 . 
     As is apparent from  FIG. 4 , spring or interference suppression contact  32  is contacted with printed circuit board  11  via a contact surface  38  which is preferably designed as a solder pad. One contact end  39  of spring contact  32  is pressed against contact surface  48  under adequate spring pretension. 
     According to  FIG. 6 , a further contact surface  40  is provided on the diametrically opposed free end of spring contact  32 . Via this contact surface  40 , spring contact  32  rests against the inner wall of pole pot  4  when the latter is mounted or pushed onto brush holder housing  10 —as is comparatively clearly apparent from  FIG. 5 . The free end of spring element  32  forming contact surface  40  is at least slightly raised out of insertion groove  37 . For this purpose, a raised stamped tab  41  is embossed into spring contact  32  in the area of contact surface  40 . 
     Brush holder housing  10  has a holding shoulder  42  which is delimited by a circumferentially molded housing or support collar  43 . This collar is used as a sealing stop for pole pot  4  mounted on holding shoulder  24 . Since contact surface  40  protrudes from insertion groove  37 , a simple yet reliably electrically conductive clamping contact connection is established between pole pot  4  and spring contact  32  when pole pot  4  is mounted. 
     Spring contact  32 , which is illustrated as a stamped sheet metal part in  FIGS. 7 and 8 , is inserted into side wall  10   a  or  10   b  via a window  44  which is provided in particular curved side wall  10   a ,  10   b . Window  44  illustrated in the figures is advantageously closed on the housing underside, so that a continuous housing edge  29  is formed in that location, at least in the area of coverage with printed circuit board  11 . 
       FIG. 3  shows the completely closed termination between particular housing side wall  10   a ,  10   b  of brush housing  10  and printed circuit board  11 . It is apparent therein that window  44  is sealed on housing underside  17  with the aid of a housing web  45 . This ensures that side wall  10   a ,  10   b , which is brought as close as possible to printed circuit board  11 , leaves no or only a small slot  46  free. A slot of this type may be sealed with the aid of a sealing lip  47 , a section of which is illustrated in  FIG. 11 , and which is attached to housing side wall  10   a ,  10   b  on housing underside  17 . 
     Due to the seal between housing  10  and printed circuit board  11 , the area of printed circuit board  11  which is covered by brush holder  9  is hermetically sealed by the board area or section of printed circuit board  11  located on the outside. As a result, it is possible to contain within housing  10  carbon dust, which is practically unavoidable and which occurs as a result of the motor rotation and the spring-loaded contacting of carbon brushes  33  on the commutator (not illustrated). Components which are mounted on printed circuit board  11  and are located outside housing  10  therefore do not come into contact with this carbon dust. 
       FIG. 7  shows contact elements  31 ,  32 , which are designed as spring contacts, in their contacting position above printed circuit board  11 . They are arranged in an approximately triangular configuration, spring contact  32  acting as the interference suppression contact being situated between the two spring contacts  31  acting as motor contacts and also set back in relation thereto—due to the curve of side wall  10   a ,  10   b.    
     Spring contacts  31 ,  32  are designed as stamped sheet metal parts and bent at an angle α between 90° and 180°. Both contact elements  31  acting as motor contacts and contact element  32  acting as the interference suppression contact each form a contact arm  31   a ,  32   a  and a holding arm  31   b  or  32   b . With the aid of holding arm  32   b , which may be designed to have latching elements, contact elements or spring contacts  31 ,  32 , are attached to corresponding housing wall  10   a ,  10   b  of brush holder housing  10  and, for this purpose, inserted into corresponding grooves therein. Contact end  39  of free-standing contact or spring arm  31   a ,  32   a  then lies under corresponding spring pretension on contact surfaces  48  of printed circuit board  11  for motor contacting or on contact surface  38  for connection to pole pot  4  in a contact-secure manner when printed circuit board  11  is inserted. 
     As is comparatively clearly apparent from  FIG. 4 , printed circuit board  11  carries, for example, two Hall sensors  48 , which are spaced a distance apart and whose sensor surfaces (not illustrated) face ring magnet  25  on printed circuit board underside  26 . 
       FIGS. 10 and 11  show an exemplary embodiment of a conventional knife or blade or clamping contact having contact elements on the brush side which are designed as flat contacts  50  and bifurcated contacts  51  on the printed circuit board side, which are mounted on printed circuit board  11 . When a printed circuit board  11  of such a design is inserted in insertion counter-direction  20 , the tines of bifurcated contacts  51  engage with particular flat contact  50  to establish a reliable clamping contact. Two contact surfaces of a Hall sensor  49  designed as a Hall IC (integrated circuit) may be seen on board underside  26  of printed circuit board  11 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.