WO2011120644A1

WO2011120644A1 - Device for assembling electric components on a printed circuit

Info

Publication number: WO2011120644A1
Application number: PCT/EP2011/001384
Authority: WO
Inventors: Bertrand Puzenat
Original assignee: Valeo Systemes Thermiques
Priority date: 2010-03-30
Filing date: 2011-03-21
Publication date: 2011-10-06
Also published as: CN102934533B; CN102934533A

Abstract

The invention relates to a device for assembling electric components on a printed circuit board, wherein said device is provided in the form of an intermediate module (2) arranged between said board (C), which is coated with a metal solder layer (CM), and said components (CC, B,...) which are to be mounted thereon, and wherein said intermediate module (2) includes: a plurality of metal linking members (3), one side of which is mounted on said board (C) by means of remelting the solder metal layer (CM), and the other side of which, remote from the board, is suitable for receiving said components; and an insulating bracket (4) combining said metal linking members (3) separately from one another.

Description

Device for assembling electrical components on a printed circuit

The present invention relates to a device for assembling electrical components or the like on a printed circuit board or board such as that, in a particular application, though not exclusively, intended for a controller of a ventilation, heating and air-conditioning system engine. of a motor vehicle, as well as said system equipped with such an assembly device.

In order to voluntarily adjust the flow rate of the air flow brought into the passenger compartment of a motor vehicle, the usual ventilation, heating and air conditioning (HVAC) systems include, in addition to heat exchangers, to obtain the expected results in terms of terms of heating, cooling, etc. , an electric motor with a blower wheel mounted on its shaft and designated by the term "fan motor unit", whose rotation speed selected by the driver from a specific button on the dashboard, is controlled from a "controller" in the form of an electronic printed circuit board to which various components are assembled.

Currently, the assembly of the contacts (lugs, pins, ...) of the electrical components thus mounted on the surface of the card is performed either:

- by a reflow soldering process which consists in passing the board, previously coated on the surface with a metal solder layer (solder paste) with the contacts of the components positioned at the surface at the selected locations, in a soldering furnace; reflow, so as to melt the metal layer on the contacts then, after cooling, obtain the assembly of the components on the card, or

- by a wave soldering process, especially when the components to be assembled are dimensionally larger, such as, for example, chemical capacitors, input filter coils or chokes, and the connections of the power source and the engine of the motorcycle fan group. It consists in passing, along the relevant surface of the board with the contacts of the components previously bonded to it, a wave of solder metal paste which secures the contacts of the components to the board by capillarity.

Although technically mastered, the process of wave soldering becomes much more difficult to implement when the choice is to use a metal alloy (often tin-based) lead-free, which is, moreover, more and more the case for reasons of health and environment.

Indeed, the absence of lead in the metal alloy causes, in return, several disadvantages, particularly that of reducing the wettability of the alloy so that the weld tends not to "settle" over the entire available surface between the contacts. and the map. An imperfect weld of the components on the board is then obtained which can subsequently contribute to the scrapping of the electronic board and its components or to malfunctions of the engine of the system and ultimately to maintenance operations or even replacement of the particularly expensive card-component assembly.

The present invention aims to overcome these drawbacks and concerns, for this purpose, a device for assembling components on a printed circuit board or board, such as that of an electric motor controller of a ventilation system. , heating and air conditioning of a vehicle, said card being coated with a weld metal layer.

According to the invention, the device is in the form of an intermediate module disposed between said card and said components intended to be mounted on it, and said intermediate module comprises:

a plurality of metallic connecting elements, on one side, on said card by reflow of the solder metal layer and able to receive, on the other side, remote from the card, said components; and

an insulating support associating, separately from one another, said metallic connection elements. Thus, thanks to the intermediate module mounted on the surface, by reflow, on the printed circuit board and grouping the "large" components, the device overcomes the disadvantages related in particular to the low wettability of the lead-free alloy used during the process wave soldering, which does not occur with the reflow soldering process. In addition, the intermediate module serving as an interface between the board and the components concerned is then attached to it while assembling the other components usually assembled by reflow during the same passage in the reflow oven, which does not imply an increase in the cost of manufacturing the card. After assembly of the module on the card, the large components (such as, in the preferred application, the power supplies of the card and the motor, the coil and the capacitor of the input filter) are reported on the metal connecting elements concerned. of the device.

According to a first feature of the invention, said metal connecting elements each have a folded tab form having a first end portion with a bearing surface for contact with said card and a second end portion for attachment to said insulating support.

Said first and second end portions of the metal connecting elements are offset parallel to one another by an inclined central portion. The insulating support is then parallel to the card and close to it, so as to minimize its size. Advantageously, this conformation of the connecting elements releases the space on the card and under the module so as to install components or others.

According to another characteristic of the invention, said insulating support forms a frame at the periphery of which are derived said metal connecting elements. In a complementary manner, said connecting elements protrude outside the frame. In other words, these connecting elements extend beyond the periphery in a direction substantially parallel to the general plane of the insulating support.

According to yet another characteristic of the invention, said metallic connecting elements extend at the level of the second parts. end, by contact terminals with which are intended to cooperate the electrical components to be mounted on the intermediate module.

Said metal connecting elements are made of copper or copper alloy and said insulating support is made of non-electrically conductive plastic material or the like thermally resistant.

Advantageously, said insulating support is overmolded on said metal connecting elements, the first end portions thereof protruding outside the support and the second end portions being embedded in said insulating support, defining side receiving slots.

Advantageously, said contact terminals have a rectangular cross section, each metal connection element comprising a terminal for connecting a corresponding contact of a component to be mounted on said intermediate module and / or two terminals spaced parallel to one of the other for the mounting force of a corresponding contact of connection from a component to be mounted.

The invention also relates to a controller or control module of a motor-blower unit motor and blower wheel of a ventilation system, heating and / or air conditioning of a motor vehicle, comprising a card or printed circuit board said board being coated with a metal solder layer CM, wherein a device for assembling components to or on the board, as defined above, is installed.

The appended figures will make it clear how the invention can be made and may serve to better define the invention, if necessary. In these figures, identical references designate similar elements.

Figure 1 shows, in perspective, an embodiment of the intermediate module assembly device according to the invention, before mounting on the printed circuit board of a ventilation system, heating and air conditioning of a vehicle. Figure 2 is a top view of the metal connection elements of the module.

Figure 3 shows, in perspective, the module assembly device, attached to the printed circuit board and carrying electrical components.

FIG. 4 is a detail view, in enlarged and cutaway perspective, of the connection of the contact tabs of a capacitor with the terminals of the relevant metal connection elements of the module.

In the exemplary embodiment illustrated in FIG. 1, the assembly device 1 of the invention is defined by an intermediate independent module 2 acting as an interface, as will be seen later with reference to FIG. a circuit board or circuit board C and electrical components CC, B to be connected by means of the device 1 at specific locations on the board. It is therefore clear that this module is separate from the printed circuit board or circuit board, the module being soldered by a reflow method on said card.

For this, the intermediate module 2 comprises metal connecting elements 3 ensuring the passage of the current between the specific locations and the electrical components to be mounted, and an insulating support 4 now between them and separately from each other, the elements of 3. In this embodiment, the module 2 has a substantially parallelepipedal flat shape given by the insulating support 4 which defines a rectangular frame. At the periphery 4A thereof are provided the connecting elements 3 which are six in number in this example, two centrally from the long sides 4B of the frame and four from two to two of the short sides 4C of the frame. Of course, a different number of connecting elements 3 and another form of support 4 could be envisaged depending on the required specificities.

More particularly, the metal connecting elements 3 are made of a conductive metal such as copper or copper alloy and preferably tinned. Structurally, each connecting element 3 presents itself in the form of folded flat tab 3A, of rectangular cross-section, having first and second end portions 3C 3C connected in parallel with each other by a central inclined portion 3D. The first flat end portion 3B constitutes a flat bearing surface 3E for contact with the printed circuit board and all of these bearing surfaces 3E elements is contained in the same plane to apply perfectly on the solder metal layer CM of the card, in order to be welded, according to the invention, by reflow. The second flat end portion 3C ensures the maintenance of each connecting element 3 with the frame of the support 4 and, as will be seen below, the electrical connection with the components.

In this regard, the support 4 is insulating from an electrical point of view and is made of a plastic material adapted to support the thermal profile of the reflow oven in which the device 1 mounted on the surface of the card must pass. Also the plastic is thermally resistant, that is to say mechanically stable as the temperature is below 260 ° C (maximum temperature of a reflow oven with CM solder layer without plomp). The obtaining of the module 2 is effected, for example, by an overmolding of the insulating support 4 with the second end portions 3C of the metal connecting elements 3 so that these, as shown in FIGS. 1 and 2, protrude perpendicularly from the sides 4B, 4C of the frame forming the insulating support.

FIGS. 1, 3 and 4 show in particular that the second end portions 3C of the elements are, after overmoulding, housed in slots 4D obtained in the support during its production, which slots 4D may be blind, for this purpose which relates to the four connecting elements from the short sides 4C, or through, with respect to the two connecting elements from the long sides 4B of the frame. All of these second flat or flattened end portions 3C are in a same plane parallel to that of the first flattened end portions 3B, an offset being made by the inclined central portions 3D of elements. In this way, the insulating support 4 is raised relative to the first parts 3B and, therefore, is parallel to the card C. It can thus receive, under the module, other common components.

Moreover, the second end portions 3C of the connecting elements 3 all extend through contact terminals 3F with which the electrical components to be mounted are co-operating. As shown in Figures 1 and 2, these terminals 3F are, in this example, flat type rectangular cross section but could be different in whole or from one element to another. In our example, the connecting elements 3 located on the short sides 4C of the insulating support 4 in the frame are each provided with a terminal 3F folded perpendicular to the second end portion 3C from which it is derived, that is, that is to say, the rectangular frame of the insulating support, being turned away from the first end portion 3B. Terminals 3F start on the side portion of the second end portion 3C which faces inwardly of the insulating support.

The terminals 3F of the two connecting elements 3 situated on the short side 4C on the left in FIG. 2, constitute the electrical power supply terminals, for example 12 volts, and the ground terminals to which the complementary terminals (contacts) not shown are connected. of the power supply source, and the terminals 3F of the two connecting elements 3 situated on the right in FIG. 2, relate to the power supply and ground terminals to which are connected those, not shown, coming from the motor group. system fan. To receive the complementary connection terminals from the power source and the motor-fan unit, the insulating support 4 has two rectangular bases 4E surmounting the latter and surrounding the relevant terminals 3F of the connecting elements. It can therefore be seen that the insulating support 4 has a central part intended to receive the electrical components to be reported and the supply terminals 3F disposed on either side of this central part, at the small side 4C of the insulating support 4. The connecting element 3 located at the center and at the top of FIG. 2 comprises four connection terminals 3F arranged perpendicularly in pairs, two of which are parallel to the general direction of the connecting element 3 so that these two terminals 3F are opposite the two terminals 3F of the connecting element 3 located in the center and bottom of Figure 2.

Similarly, the other two terminals 3F of the connecting element 3 located at the center and at the top of FIG. 2 are placed in the extension and opposite the terminals 3F of the connecting element 3 located at the top left of Figure 2. This arrangement of terminals 3F allows to install:

a first component between the connecting element 3 situated at the top left of FIG. 2 and the connecting element 3 located at the center and at the top of this same figure, and a second component between the connecting element 3 situated above and in the center of Figure 2 and the connecting element 3 located at the bottom and center this same figure.

As shown in FIG. 4, the fixing of the tabs P forming the contacts of the capacitor or chemical capacitance CC is effected by pinching obtained from two flat terminals 3F spaced parallel to one another and originating from the second parts of end 3C of the metal connecting elements located on the long sides 4B of the frame insulating support 4. These terminals 3F are in the extension of the second end portions 3C, parallel to the plane of the support, so that the legs P form cylindrical insert force between the two respective parallel terminals of the connecting elements 3.

It is the same to fix the non-visible contact tabs of the coil B partially illustrated in FIG. 3, and which force fit between pairs of parallel terminals 3F facing each other from two connecting elements. adjacent 3, one on the short side 4C and the other on the long side 4B, as best seen in Figure 2.

The insulating support 4 has in its central part bars having holes (two per bar) of axis perpendicular to the terminals 3F 3. The function of these holes is to provide access to pass the claws of a clamp whose purpose is to clamp the two adjacent terminals 3F against tabs P forming the contacts of the components to report on the modules 2.

As shown in FIG. 3, before assembling the components on the intermediate module 2 of the assembly device 1, the bearing surfaces 3E of the first end portions 3B of the metal connecting elements 4 are positioned at predetermined locations of C card, where is the CM solder metal layer. The latter obviously serves to secure common components, not shown, other than those, larger, intended for the assembly device 1.

Through the passage of the printed circuit board C and the assembly device 1 surface-mounted thereon in the non-illustrated reflow oven, the heat of which melts the layer CM (batter shaving) ensuring the welding, after cooling, the first end portions 3B are secured via the bearing surfaces of the metal connection elements of the module 2 on the card C, as well as that of the usual components provided directly on the card C. the soldering (soldering) by reflow does not imply the wettability problems generated by the wave soldering, the assembly device 1 is perfectly fixed to the card by ensuring, by the metal connecting elements 3, the electrical conduction between board and components to be mounted on the module, especially since these copper or copper alloy elements are tinned to be compatible with the lead-free reflow process (eg n with nickel undercoat).

After leaving the reflow oven and cooling, connections not shown, such as those of the power source and the motor-fan unit, are plugged into the respective bases 4E of the intermediate module 2 and connected to the relevant parallel contact terminals 3F. Then, the tabs P of the chemical capacitor CC and the coil B of the large components are force-fed and pinched by the parallel terminals. corresponding 3F. This operation can be done using a specific tool not shown and is facilitated by the holes in the bars of the insulating support 4 to access these terminals. Other means for fixing the tabs on the terminals could be envisaged, such as laser fastening in particular.

Claims

1. Device for assembling electrical components or the like on a printed circuit board or board, characterized in that it is in the form of an intermediate module (2) arranged between said board (C) and said components ( CC, B, ...) intended to be mounted thereto, and in that said intermediate module (2) comprises:

- A plurality of metal connecting elements (3) adapted to be reported on one side, on said card (C) by reflow and able to receive, on the other side, remote from the card, said components; and

- an insulating support (4) associating, separately from each other, said metal connecting elements (3).

2. Device according to claim 1, wherein said metal connecting elements (3) each have a folded leg shape (3A) having a first end portion (3B) with a bearing surface (3E) for contact with said card and a second end portion (3C) for attachment to said insulating support (4).

3. Device according to the preceding claim wherein said first and second end portions (3B, 3C) of the metal connecting elements (3) are offset parallel to each other by an inclined central portion (3D).

4. Device according to one of the preceding claims 1 to 3, wherein said insulating support (4) forms a frame at the periphery (4A) which are derived from said metal connecting elements (3).

5. Device according to claim 4, wherein said connecting elements (3) project externally to the frame.

6. Device according to any one of the preceding claims, wherein said metal connecting elements (3) are extended at the second end portions (3C) by terminals (3F) with which are intended to cooperate the electrical components to be mounted on the intermediate module (2).

7. Device according to any one of the preceding claims, wherein said metal connecting elements (3) are made of copper or copper alloy.

8. Device according to any one of the preceding claims, wherein said insulating support (4) is made of plastic or thermally resistant material.

9. Device according to the preceding claim, wherein said insulating support (4) is overmolded on said metal connecting elements (3), the first end portions (3B) thereof protruding externally from the support (4) and the second end portions (3C) being embedded in said insulating support (4), defining side receiving slits (4D).

10. Device according to claim 6, wherein said terminals (3F) have a rectangular cross section, each metal connecting element (3) comprising a terminal for connecting a corresponding contact of a component to be mounted on said intermediate module. (2) and / or two terminals spaced parallel to each other for force mounting a corresponding contact of connection from a component to be mounted.

1 1. Controller of a motor-driven fan motor unit and blower wheel of a ventilation, heating and / or air-conditioning system for a motor vehicle, comprising a printed circuit board or board, said board being coated with a metal welding layer (CM), characterized in that it is equipped with an assembly device (1) as defined according to any one of the preceding claims.