Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of PCT International Application No. PCT/EP2007/000951, filed on Feb. 5, 2007, which claims priority under 35 U.S.C. §119 to German Application No. 10 2006 005 941.7, filed Feb. 9, 2006, the entire disclosures of which are expressly incorporated by reference herein. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    The present invention relates to a holder with a device for retaining a flexible circuit board. 
         [0003]    Electrical connections between and within complex subassemblies are increasingly being realized using flexible circuit boards, also referred to as flexible foils. In comparison with electrical cable connections, these have a series of advantages. A flexible circuit board allows good movement of components of the subassemblies in relation to one another, in particular also during fitting. Furthermore, in comparison with conventional cables, a flexible circuit board takes up less space and, at the same time, can be subjected to relatively high mechanical loading. A flexible circuit board is used to connect, for example, various electronic components, such as sensors, actuators, etc., electrically to a control electronics unit. The prior art discloses various holders for connecting such electronic or mechatronic components electrically to the flexible circuit board and for retaining the flexible circuit board itself For example, there are holders in existence which provide strain relief for the flexible circuit board during fitting and operation of mechanical and/or electronic components which can move in relation to one another. 
         [0004]    The object of the invention is to provide a holder for flexible circuit boards which allows particularly straightforward and cost-effective fitting of the flexible circuit board and of the components connected thereto. 
         [0005]    This object is achieved by the features of the independent claim. 
         [0006]    Advantageous embodiments of the invention are given in the dependent claims. 
         [0007]    The invention builds on the retaining means of the generic type for flexible circuit boards in that the holder has at least one further device for retaining at least one component, it being possible for the component to be connected to the flexible circuit board. It has proven to be advantageous to provide, on the holder for the flexible circuit board, retaining devices for further components which can be connected to the flexible circuit board. This reduces the number of retaining means during production and subsequent fitting, and the overall production costs decrease as a result. Furthermore, the component or the further components is/are already located in the immediate vicinity of the flexible circuit board to which they are to be connected. This reduces the necessary length of the connecting paths, makes it easier to arrange the components which are to be connected and reduces the number of additional connecting elements required between the circuit board and component. 
         [0008]    In the case of a likewise preferred embodiment, it is provided that the component forms an electrical connection. This may be, for example, the electrical connection of a sensor, of an actuator or of other electrical components which are to be connected electrically to the flexible circuit board. It is thus possible, on the holder, for individual components of the subassemblies to be connected to the flexible circuit board itself by means of the component. It is thus possible for any mechanical or thermal loading which may occur during fitting or operation to be absorbed by the component, which, in comparison with the flexible circuit board, can usually be better equipped in this respect. 
         [0009]    In the case of an alternative embodiment, it may be provided that the component forms an active element. A short connection between the element and the flexible circuit board is advantageous, in particular, in the case of active elements. 
         [0010]    Moreover, it may advantageously be provided that the active element is a sensor. In particular sensors profit from particularly short connecting paths since often only low signal heights are present and/or undesirable interference signals may be impressed on the measuring signal as a result of long connecting paths. 
         [0011]    In the case of a likewise preferred embodiment, it is provided that the sensor is a displacement, a speed and/or a temperature sensor. For example, it is possible for an active element comprising a combination of a speed sensor and a temperature sensor to be fastened on the holder and for the plug-in connection thereof to be connected to the flexible circuit board. 
         [0012]    In the case of an advantageous embodiment, it may be provided that the component has a leadframe. It is thus possible, in particular, for leadframe ends of a sensor which have been secured by injection molding to be advantageously retained and positioned. 
         [0013]    It may likewise advantageously be provided that the component has a strain relief device. Such a strain relief device may be advantageous in a number of application cases. For example, the flexible circuit board itself may require a strain relief device upon contact connection with an electronics unit. Furthermore, however, it is also the case that the further components which can be fastened on the holder are often connected to mechanically loaded components both during fitting and during operation. In this case, it is likewise possible to provide devices on the component which absorb tensile forces for example in cables, sheathed leadframe ends, etc. 
         [0014]    Analogously, it may likewise be the case with an advantageous embodiment that the component provides an antikink means. It is preferably even possible to realize a strain relief device and antikink means in a single suitable form of the component. 
         [0015]    Furthermore, in the case of a likewise preferred embodiment, it may be provided that the further device essentially secures the position of the component in relation to the holder. In particular in the case of components which can be electrically connected directly to the flexible circuit board, it is advantageous to secure the position of the second component relative to the holder, thus also relative to the flexible circuit board. This does away with the need for a further positioning step, which would be necessary according to the prior art. Furthermore, this results in a higher degree of reliability during operation of the subassembly as a whole since, in the case of a corresponding configuration of the holder, it is not possible for the position between the flexible circuit board and component to change. 
         [0016]    A likewise advantageous embodiment provides that the connection between the component and the holder, the connection being created by means of the further device, is releasable. This is advantageous, in particular, in respect of fitting and/or repair. 
         [0017]    In particular, a likewise advantageous embodiment provides that the further device is a latching device and/or plug-in device. This facilitates the installation of the component during fitting and/or repair or changeover work. 
         [0018]    A further, likewise advantageous embodiment is characterized in that the component has a guide for electrical connections. This makes it possible to facilitate the handling of the component and the connections, in particular, during fitting and repair work. 
         [0019]    The invention is based on the finding that, in a central retaining and/or carrying element, it is possible to combine in one part a number of functions which are usually performed by a number of separate parts. The central carrying element here performs the following functions: it retains and fixes a flexible circuit board, and it forms a strain relief device and an antikink means for the flexible circuit board upon contact connection with an electronics unit. Furthermore, the carrying element performs the functions of retaining and positioning connections, in particular a plug-in connection of a sensor, and feeds the flexible circuit board to this sensor. Furthermore, it is also possible for cable and leadframe connections of sensors to be retained and positioned on this carrying element. 
         [0020]    Other objects, advantages and novel features of the present invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0021]      FIG. 1  shows a sectional view of a first preferred embodiment of the holder according to the invention; and 
           [0022]      FIG. 2  shows a sectional view, in detail form, of a second, likewise preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION  
       [0023]    In the following description of the drawings, like designations are used to designate like or comparable components. 
         [0024]      FIG. 1  shows a sectional view of a first preferred embodiment of the holder  10  according to the invention. The central holder  10 , which is produced from plastic, serves for retaining the flexible circuit board  14  and further components, as will be explained hereinbelow. The central plastic holder  10  can be subdivided, to facilitate explanation, into four portions A, B, C and D. In the portions A and B, the flexible circuit board  14  runs essentially in a first plane E 1 , whereas, in the portions C and D, it runs in a second, lower-level plane E 2 . 
         [0025]    In portion A, the central plastic holder  10  has a sensor-retaining means  22 . This sensor-retaining means  22  has introduced into it an active element  32 , of which, for illustrative reasons, only a top part is depicted. The active element  32  is a combined speed and temperature sensor. The active element  32  has a contact pin  44  via which electrical contact connection can be produced between the active element  32  and the flexible circuit board  14 . 
         [0026]    In portion B, a strain relief device  26  is provided on the central plastic holder  10  as a constituent part of the retaining device  12  since, alongside its regions which run essentially parallel to the central plastic holder  10 , the flexible circuit board  14  has a free region  15  which leads to an electronics unit (not depicted). The strain relief device  26  has protrusions  46  which engage in correspondingly configured apertures  48  in the flexible circuit board  14 . A latching part  36  interacts with the strain relief device  26 . This latching part  36  has apertures  50  which at least essentially correspond, in terms of diameter and arrangement, with the protrusions  46  of the strain relief device  26 . The latching part  36  also has a latching nose  52 , which engages in a through-passage  54  in the central plastic holder  10 , and an antikink portion  60 . As seen in cross section, the shape of the latching part  36  in its region  56  corresponds to the shape of the central plastic holder  10  in its region  58 , i.e. the latching part  36  and central plastic carrier run largely parallel there. 
         [0027]    When the flexible circuit board  14  is fitted onto the central plastic holder  10 , the flexible circuit board  14  is aligned, by way of its apertures  48 , in relation to the protrusions  46  and is fitted onto the central plastic carrier  10 . The latching part  36  is then aligned, in respect of its apertures  50 , with the protrusions  46 . The latching nose  52  is then guided through the lead-through  54  and thus latched to the central plastic holder  10 . The flexible circuit board  14  here is subjected to a pressure which extends over that entire surface of the flexible circuit board  14  which is covered by the latching part  46 . On the one hand, this provides strain relief for any forces which may possibly arise at the free end  15  of the flexible circuit board  14 . On the other hand, the course which the flexible circuit board  14  takes along the central plastic holder  10  is defined and this gives rise, in particular, to the flexible circuit board  14  changing from the plane E 1  to the plane E 2  on account of the interaction between the portion  56  of the latching part  36  and the region  58  of the central plastic holder  10 . The suitably selected radius of curvature of the latching part  36  at the antikink portion  60  thereof, at the same time, counteracts any undesirable warping of the flexible circuit board  14  in the case of tensile forces which may possibly arise in the free region  15  of the flexible circuit board  14 . 
         [0028]    In the portion C, the flexible circuit board  14  is guided parallel to the central plastic holder  10 , and it therefore connects the regions B and D. 
         [0029]    In portion D, a plug-in depression  20  is provided in the central plastic holder  10 . A transfer unit  30  can be introduced into this plug-in depression  20 . This transfer unit has a contact pin  62  on its top side and lateral contact surfaces  64 , to which a flex or a pin of an electromechanical component can be soldered. The transfer unit  30  can be introduced into the plug-in depression  20 , and thus fastened therein, by way of its underside. This can be assisted, as depicted, for example in the case of an appropriately selected combination of materials, by suitable sawtooth-like outer contouring. A latching wedge  38  together with a cable-guiding device  28  of the central plastic holder  10  is also provided in portion D. In a manner analogous to the latching part  36 , the latching wedge  38  has a latching nose  66 , which can be introduced into the latching lead-through  68  and latched there. Moreover, the latching wedge  38  has a widening wedge-shaped portion  70 . This interacts with a cable-guiding portion  72  of the central plastic holder  10 . In this cable-guiding portion  72 , for example, the sensor-connection cables  42  are guided to the transfer unit  30 . Once the latching wedge  38 , in particular the wedge-shaped portion  70 , has been introduced into the cable-guiding device  28 , the sensor-connection cables  42  are clamped within the cable-guiding portion  72 , in which case the sensor-connection cables  42  are positioned and relieved of strain. 
         [0030]      FIG. 2  shows a sectional view, in detail form, of a second, likewise preferred embodiment. In this sectional view, in detail form, an alternative embodiment of the central plastic holder  10  is illustrated for the portion D. Instead of the sensor connections being fed by means of a cable, as is depicted in  FIG. 1 , in this embodiment the sensor connections are supplied via a sheathed leadframe  34 . The sheathed leadframe  34  comprises two sensor arms  74 ,  76 , which are configured for movement in relation to one another via an exposed leadframe portion  40 . The sensor arm  74 , which is angled upward through ninety degrees during fitting, as is illustrated in  FIG. 2 , has a contact pin  78  which can be soldered to the flexible circuit board  14 . The sensor arm  76 , which remains horizontal, contains a groove  80  into which engages a plastic rib  82  of the central plastic holder  10  for the purposes of stabilizing and fixing the sensor arm  76 . The leadframe end  74  is positioned and retained in a retaining means  24  of the central plastic holder  10 . Furthermore, the leadframe end  74  additionally has a supporting portion  84 , which rests on a bearing means  86  on a diecast bottom part, which is only partially indicated in  FIG. 2 . This supporting portion  84  additionally positions the sheathed sensor connection  34  and supports the same. It is also possible for further bearing means to be provided on the horizontal sensor arm  76 . 
         [0031]    Those features of the invention which are disclosed in the above description, in the drawings and in the claims may be essential both individually and in any desired combination for the purpose of realizing the invention. 
         [0032]    The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 
       LIST OF DESIGNATIONS 
       [0000]    
       
           10  central plastic holder 
           12  retaining device 
           14  flexible circuit board 
           15  free end of the flexible circuit board 
           20  plug-in depression 
           22  sensor mount 
           24  leadframe-end retaining means 
           26  strain relief device 
           28  cable-guiding device 
           30  transfer unit 
           32  active element 
           34  sensor leadframe 
           36  latching part 
           38  latching wedge 
           40  exposed leadframe portion 
           42  sensor-connection cable 
           44  contact pin 
           46  protrusions 
           48  apertures in flexible circuit board 
           50  apertures in latching part 
           52  latching nose 
           54  latching lead-through 
           56  plane-changeover region 
           58  plane-changeover region 
           60  antikink portion 
           62  transfer-unit contact pin 
           64  soldering contact surface 
           66  latching nose 
           68  latching lead-through 
           70  wedge-shaped portion 
           72  cable guide 
           74  leadframe end 
           76  horizontal sensor arm 
           78  contact pin 
           80  groove 
           82  plastic rib 
           84  supporting portion 
           86  bearing means 
         A, B, C, D portions of the central plastic holder 
         E 1 , E 2  planes of the flexible circuit board

Technology Category: 5