Abstract:
The invention relates to a combined fastening and contacting system for electrical components on superimposed circuit boards in an electronic housing, especially for the automobile sector, as well as a method for fastening and contacting electrical components. The novel fastening and contacting system has two parts, one of which is embodied as a holding frame for electrical components while the other part is configured as a pressing frame for fixing the holding frame. There is formed a combined fastening and contacting system for electrical components on superimposed circuit boards, which makes it possible to replace faulty electrical components in a simple fashion while allowing superimposed circuit boards to be electrically contacted in a safe manner. The system is particularly suitable for the automobile sector.

Description:
BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The invention relates to a combined fastening and contacting system for electrical components on superimposed circuit boards for an electronic housing, in particular for the automobile sector. 
   The fixing of wired component parts to the circuit board using hot-melt adhesive is known from the prior art. 
   To this end, EP 0 419 065 A2 discloses a method, in which, on its first side in a soldering paste printing station, a circuit board is firstly printed with solder areas at the points provided to attach SMD components (SMD=Service Mounted Device). In an adhesive station, the circuit board is then provided with a droplet of adhesive between the soldering points to fix the SMD components and is subsequently equipped with SMD components on a pick and place machine, said components being placed on the solder areas and the adhesive. As the components have to be pressed into the adhesive, the precise attachment of the components can be impeded by the adhesive. After the assembly process, the adhesive hardens and the circuit board is conveyed to a reflow soldering station, in which the solder imprinted on the first side is melted and the components are soldered to the circuit board. After the first reflow soldering step, the circuit boards are turned with the second side uppermost and are printed again with solder areas and then equipped with SMD components. 
   DE 199 13 660 A1 discloses a method for fastening electrical components to circuit boards, which are enclosed by a housing, with the components being held by a holding device. In this process, the electrical component is held in the circuit board during the assembly and during operation by means of a holding device and is adhesively connected to a housing surface of the housing surrounding the circuit board. 
   The use of adhesive is disadvantageous in that this creates a non-detachable connection between the component parts to be connected. This results in the entire assembly being rendered unusable in the event of an electrical component being faulty. In addition, the adhesive now fulfils the function of safely fixing the electrical components in a position, but does not provide the possibility of electrically contacting superimposed circuit boards in a safe manner. Flexible elements are needed for this, such as flat ribbon cables for instance. The disadvantages with the use of flat ribbon cables consists in a maximum power transmission mostly only being possible for signal contacts and the positioning on the circuit board having a mostly negative affect on the electromagnetic compatibility. High demands are also placed on the vibrational resistance of the freely-oscillating cable, which can also already be damaged or destroyed during assembly, particularly in electronic housings for the automobile sector. In particular, longer cables exhibit high losses for critical power levels and have a negative effect on the electromagnetic compatibility. It is particularly disadvantageous when using plug connections that the plug connection requires a housing, which in turn demands an increased amount of space. 
   A service box emanates from DE 42 08 765 A1, which has one or a number of printed circuit boards which are separated from one another by means of insulation having printed circuits made of conductive material attached to one or both sides thereof, onto which component parts are plugged and soldered, with the printed circuits on both sides of a printed circuit board or the printed circuits of several printed circuit boards being electrically conductively connected by means of pins. It is however disadvantageous here for the pins enabling the electrical contacting to have to be precisely inserted into a plug holder, which results in an assembly problem as a result of the plurality of pins and the mechanical overdefinition associated therewith. 
   BRIEF SUMMARY OF THE INVENTION 
   Based on this, the object underlying the present invention is to create a combined fastening and contacting system for electrical components on superimposed circuit boards, which enables faulty electrical components to be replaced in a simple fashion while also allowing superimposed circuit boards to be electrically contacted in a safe manner. 
   This object is achieved by a combined fastening and contacting system with the features of claim  1  as well as by a method for fastening and contacting electrical components. Advantageous configurations and developments, which can be used individually or in combination with one another, are the subject matter of the dependent claims. 
   The inventive, combined fastening and contacting system for electrical components on superimposed circuit boards is characterized in that the system has two parts, one of which is embodied as a holding frame for electrical components while the other is configured as a pressing frame with pressing pins. In accordance with the invention, provision is made to fix the circuit board between the holding frame and pressing frame, with the pressing frame being arranged on the underside of the circuit board and the holding frame being mounted on the circuit board. The holding frame is fixed by the pressing spikes of the pressing frame, which are guided through the circuit board. The pressing frame defines the distance between the circuit board and stabilizes the circuit board mounted in a sandwich-like fashion between the holding frame and the pressing frame, if it is subjected to vibrations. It is also advantageous for this circuit board to be pressed onto the heat sink, thereby enabling an optimum cooling effect. 
   The holding frame dispenses with the need for screw holes on the main circuit board. An improved routing of the processor is also possible. 
   The pressing pins can be advantageously positioned in a flexible fashion so that their arrangement can be adjusted to the respective conditions in the electronic housing. It is also advantageous for the pressing pins to be flexibly and elastically tied to the pressing frame, so that possible tolerances are balanced. This also enables a balancing in respect of the overdefinition of the superimposed circuit boards, which is benefited by the Z-geometry of the pressing pins and by the elastic configuration of the pin receptacle. In addition, the pressing pins can be used both for signal and power lines. In respect of the electromagnetic compatibility, it is also possible to position the pressing pins in the vicinity of the plug. A high number of pins is also possible by means of a compact design. 
   It is also advantageous for the two circuit boards to be able to be assembled outside the housing, as a result of which the examination of electrical contactings can also be simplified. The final assembly of the circuit board unit in the electronic housing can be easily implemented. 
   It is preferred for the circuit board to be mounted between the holding frame and the pressing pins in a sandwich-like fashion. This arrangement allows the circuit board to be mounted in a vibration-safe fashion, as a result of which a safe electrical contacting of the superimposed circuit boards is achieved. It is also preferred for the holding frame to have differently shaped connectors for the electrical components. This results in it also being possible to safely fix exotic electrical components. 
   It is advantageous if the holding frame has penetration bores, which accommodate the pressing spikes of the pressing frame so that the holding frame is fixedly positioned on the circuit board. No additional tools, such screws as for instance, are needed to fix the holding frame. 
   The pressing frame preferably has pressing spikes for the penetration bores of the holding frame, it being by means of pressing technology within the production step, both to position the holding frame in a fixed position and also to carry out the contacting between the circuit boards. 
   It is also preferred if the pressing frame has centering pins. These facilitate the precise positioning of the circuit board prior to the pressing process and thus serve as pre-centering means. 
   It is advantageous if the pressing pins are designed to be Z-shaped, so that a balance in respect of the overdefinition of both circuit boards is possible. 
   It is also advantageous for the pressing frame to have positioning bolts, which allow it to be fixed to the main circuit board. 
   The method according to the invention for fastening and contacting electrical components on superimposed circuit boards in an electronic housing has the following steps: positioning a holding frame with penetration bores and connectors for electrical components on the top side of a circuit board; equipping the holding frame with electrical components; positioning a pressing frame with pressing spikes, centering pins and positioning bolts below the circuit board; pressing the centering pins and pressing pins into the circuit board and/or pressing the pressing spike into the penetration bores of the holding frame to form a combined module; pressing this combined module by means of pressing pins and positioning bolts of the pressing frame on a main circuit board and screwing the circuit boards fixed one above the other in an electronic housing. 
   The advantage of the method according to the invention lies in both the fastening of the electrical components as well as the electrical contacting of a circuit board being carried out by the pressing pins in one working step. In addition, faulty electrical components can be replaced in a simple fashion, since they are not fastened using adhesive. 
   The present invention advantageously firstly produces a combined fastening and contacting system for electrical components on superimposed circuit boards, which allows faulty electrical components to be replaced in a simple fashion as well as allowing superimposed circuit boards to be electrically contacted in a safe fashion. It is suited in particular to the automobile sector. 

   
     Further advantages and embodiments of the invention are described in detail below with reference to exemplary embodiments as well as the drawings, in which; 
     BRIEF DESCRIPTION OF THE SEVERAL OF THE DRAWING 
       FIG. 1  shows a schematic representation of a top view of a first exemplary embodiment of an inventive holding frame for electrical components prior to positioning on a circuit board; 
       FIG. 2  shows a schematic representation of a top view of the holding frame as claimed in  FIG. 1 , after positioning on the circuit board; 
       FIG. 3  shows a schematic representation of a top view of a first exemplary embodiment of a pressing frame according to the invention; 
       FIG. 4  shows a schematic representation of a top view of a second exemplary embodiment of the pressing frame according to the invention; 
       FIG. 5  shows a schematic representation of a perspective view of the holding frame positioned on the circuit board prior to pressing the pressing frame; 
       FIG. 6  shows a schematic representation of a perspective view of a combined module comprising a holding frame, circuit board, pressing frame prior to pressing into a main circuit board; 
       FIG. 7  shows a schematic representation of a perspective view of the combined module as claimed in  FIG. 6  after pressing into a main circuit board; 
       FIG. 8  shows a schematic representation of a perspective view of the combined module after assembly in an electronic housing; 
       FIG. 9  shows a schematic representation of a perspective view of the assembly of the combined module in the electronic housing; 
       FIG. 10  shows a schematic representation of a perspective view of the holding frame positioned on the circuit board prior to pressing a further inventive pressing frame; 
       FIG. 11  shows a schematic representation of a perspective view of a penetration hole of an inventive holding frame as well as a pressing spike of an inventive pressing frame prior to the pressing process; 
       FIG. 12  shows a schematic representation of a perspective view of a centering pin of a holding frame prior to pressing into a circuit board; 
       FIG. 13  shows a schematic representation of a perspective view of the pressing process of the centering pins; 
       FIG. 14  shows a schematic representation of a perspective view of the combined module comprising a holding frame, circuit board and pressing frame prior to pressing into a main circuit board; and 
       FIG. 15  shows a schematic representation of a perspective view of the combined module after assembly in an electronic housing. 
   

   DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a top view of a first exemplary embodiment of an inventive holding frame  1  for electrical components prior to positioning on a circuit board  3  equipped with electrical components  2 . The holding frame  1  can be adjusted to the spatial conditions on the circuit board  3  in respect of its geometric form and is thus fully variable. The holding frame  1  has connectors  4 ,  5 , which are suited both to accommodating concentric, as well as quadratic wired components, with other geometric form also being conceivable here. In addition, penetration bores  6  are arranged on different contact points of the holding frame  1 , said penetration bores subsequently being used to accommodate pressing spikes during the pressing process. 
     FIG. 2  shows a top view of the holding frame  1  according to  FIG. 1  after positioning the circuit board  3  and after equipping it with electrical components  7 . 
     FIG. 3  shows a top view of a first exemplary embodiment of a pressing frame  8  according to the invention. The pressing frame  8  has two bars  9 ,  10  which preferably run in parallel to one another and which are fixedly positioned preferably by means of three transverse bars  11 ,  12 ,  13 . In this way, the transverse bars  11 ,  12 ,  13  preferably form an angle of 90° with the bars  9 ,  10 , with the respective end regions of the bars  9 ,  10  terminating with the transverse bars  11  and/or  13 . 
   The transverse bar  12  is located between the transverse bars  11  and  13 . Pressing spikes  14 ,  15 ,  16  are embodied on the bars  9 ,  10  as well as preferably centrally on the transverse bar  12 , said pressing spikes being arranged in a positionally-identical fashion, i.e. at the same distance from the penetration bores  6  of the holding frame  1 . The pressing spikes  14 ,  15 ,  16  have a preferably concentric bolt-like base body  17 , which ends in a stud-like pin  18 , which has a smaller diameter than the bolt-like base body  17 . The transverse connectors  11  and  12  have at their  4  end regions preferably concentrically embodied positioning bolts  19 ,  20 ,  21 ,  22 . The transverse bar  11 , into which the bars  9 ,  10  lead on one side, leads into a central bar  23  on the other side. The central bar  23  leads into a pressing bar  24  which runs in parallel to the bar  11 . The pressing bar  24  has connector regions  25 ,  26  with connectors above and below the middle bar  23  in each instance, in which connector regions Z-shaped pressing pins  27  are preferably mounted. The connectors of the connector regions  25 ,  26  can also preferably be arranged one below the other, so that the pressing pins  27  can be connected in two rows. The transverse bar  13 , into which the opposite end regions of the bars  9 ,  10  lead, likewise has connector regions  28 ,  29 , into which pressing pins  27  are mounted. 
     FIG. 4  shows a top view of a second exemplary embodiment of the pressing frame  8  according to the invention. In contrast to the first exemplary embodiment, the bars  9 ,  10  lead into the transverse bar  12 . Connector regions  30 ,  31  are arranged on the positioning bolts  21 ,  22 , said connector regions preferably forming an angle of 90° with the transverse bar  12 . All further features were already described in  FIG. 3 . 
     FIG. 5  shows a perspective view of the holding frame  1  positioned on the circuit board  3 , prior to pressing the pressing frame  8  into the penetration bores  6  of the holding frame  1  as well as the bores of the circuit board  3  provided for the pressing pins  27 . The combined fastening and contacting system according to the invention is thus designed in two parts and includes the holding frame  1  as well as the pressing frame  8 . 
     FIG. 6  shows a perspective view of a combined module  32  comprising a holding frame  1 , circuit board  3  and pressing frame  8 , prior to pressing into a main circuit board  33 . In this way, the positioning bolts  19 ,  20 ,  21 ,  22  are used as spacers between the superimposed circuit boards  3 ,  33  following the pressing process. 
     FIG. 7  shows a perspective view of the combined module  32  according to  FIG. 6  following the pressing into the main circuit board  33 . 
     FIG. 8  shows a perspective view of the combined module  32  with a main circuit board  33  following assembly into an electronic housing, which is preferably designed in two parts, comprising a housing cover  35  and a housing base  36 . The main circuit board  33  and/or the combined module  32  are fastened to the housing cover  35  by means of fastening means  37 ,  38 , such as screws for instance. One fastening possibility consists in fastening the main circuit board  33  to the housing cover  35  with a small screw  38 , and in fastening the combined module  32  to the housing cover  23  with a large screw  37 , which is guided through the main circuit board  33  and through the circuit board  35 . A sleeve  43 , preferably a metal sleeve  42 , is guided along the thread element of the screw  37 , said metal sleeve pressing the circuit board  3  against the housing cover  35  during the screwing process. 
     FIG. 9  shows a perspective view of the assembly of the combined module  32  and/or the main circuit board  33  into the electronic housing  34  by means of the fastening means  37 ,  38 . 
     FIG. 10  shows a perspective view of the holding frame  1  positioned on the circuit board  3  prior to pressing the pressing frame  8  according to the invention. With the exemplary embodiment illustrated here, an elastic middle bar  23   a  is preferably arranged in each instance centrally on the transverse bars  11   a ,  12   a , said middle bar leading into pressing bar  24   a , with the pressing bar  24   a , which runs in parallel to the transverse bars  11   a ,  12   a , having an elastic center region  39 , which, leads into a connector region  41 ,  41  for the pressing pin  27  on both sides. The connector regions  40 ,  41  each preferably have two centered pins  42 . 
     FIG. 11  shows a perspective view of a penetration bore  6  of a holding frame  1  according to the invention as well as a pressing spike  16  of a pressing frame  8  according to the invention prior to the pressing process. 
     FIG. 12  shows a perspective view of a centering pin  42  of a pressing frame  8  prior to the pressing process with the pressing direction shown in the direction of the arrow. 
     FIG. 13  shows a perspective view of the centering pin  42  of the pressing frame  8  according to  FIG. 12 , following the pressing process with the pressing direction shown in the direction of the arrow. 
     FIG. 14  shows a perspective view of the combined module  32 , comprising a holding frame  1 , circuit board  3  and pressing frame  8  prior to pressing into the main circuit board. 
     FIG. 15  shows a perspective view of the combined module  32  with a main circuit board  33  following assembly in the electronic housing  34 . The main circuit board  33  and/or the combined module  32  are fastened to the housing cover  35  by means of screws  44 ,  45 . Provision is made here for the screw  44  to fasten the main circuit board  33  to the housing cover  35 . The screw  45  is embodied such that the screw head protrudes over the circuit board  33  and does not rest on the circuit board  33 . A sleeve  46 , preferably a metal sleeve, is embodied along the thread element of the screw  45 , said metal sleeve pushing the circuit board  3  onto the housing cover  35  by means of the screwing process. The screw  45  with the sleeve  46  is preferably inserted through an opening  47  in the circuit board  33  and into a guide connecting piece  48  preferably made of plastic, by means of screwing, before the combined module  32  is fastened to the housing cover  35 . The diameter of the opening  47  is here greater than the diameter of the screw thread of the screw  45  with the sleeve  46 . The guide connecting piece  48  thus does not rest on the circuit board  33 . The guide connecting piece  48  and the opening  47  thus have tolerance regions, which prevent the circuit board  33  from also being permanently fixed by means of the screw  45 . This alternative fastening prevents the circuit board  33  from being subjected to any stress, which could result in electrical contactings being interrupted. 
   The present invention firstly advantageously achieves a combined fastening and contacting system for electrical components on superimposed circuit boards, which allows faulty electrical components to be replaced in a simple fashion as well as allowing superimposed circuit boards to be electrically contacted in a safe manner. It is particularly suited to the automobile sector.