FR3052014A1 - CONTROL UNIT UNIT AND METHOD FOR ELECTRICALLY CONNECTING AN ENCAPED GRID COMPRISING COMPONENTS INSTALLED ON THE MOUNTING SURFACE OF A CIRCUIT PLATE MEMBER - Google Patents

Abstract

Control unit unit (1) having a circuit board element (10) with components (30, 31, 32) on its mounting surface (20), and a stamped grid (40) on the side of the element (10) opposite its mounting surface (20), the stamped grid (40) being made of copper or aluminum. The unit includes a branch member (60) connecting the grid (40) to the electrical components (30, 31, 32) by being installed on the mounting surface (20).

Description

Field of the invention

The present invention relates to a control unit unit for a motor vehicle comprising a circuit board element with electrical components installed on the mounting surface of this circuit board element and a stamped gate installed on the side of the circuit board element. the circuit board element opposite the mounting surface for electrically connecting the components of the mounting surface, the drawn gate being substantially copper or aluminum. The invention also relates to a method for electrically connecting a substantially copper or aluminum stamped grid to electrical components installed on the mounting surface of a circuit board member.

State of the art

A large number of control unit units are known, including gearbox control modules. These modules must operate in a high temperature oil environment (up to about 150 ° C) and with a long service life. The control units are connected to other elements such as sensors by flexible films, cables or soldered pins. Document DE 10 2010 030 528 A1 describes an encapsulated control module of a motor vehicle whose electronic assemblies are installed on a plate and are encapsulated.

Known control unit units have the disadvantage of requiring a hermetic closure of the control unit unit and connections to avoid electrochemical corrosion. Electrochemical corrosion typically reduces the service life of the control unit units. However, in general, sealing the connections is technically complicated.

Purpose of the invention

The object of the present invention is to develop a control unit unit and its manufacturing method, with simple means, while offering a long service life for operation in an oil environment.

DISCLOSURE AND ADVANTAGES OF THE INVENTION For this purpose, the subject of the present invention is a control apparatus unit of the type defined above, characterized in that it comprises a connection element electrically connecting the stamped gate to the electrical components. of the mounting surface being installed on the mounting surface, the connecting element being substantially made of the same material as the stamped grid.

In other words, the invention relates to a control unit unit intended in particular for a motor vehicle. This unit includes a circuit board element whose mounting surface is equipped with electrical components. The side of the circuit board member, opposite the mounting surface, receives a stamped grid for electrical connection of the components installed on the mounting surface; the stamped grid is practically made of copper or aluminum. The unit also includes a branch member electrically connecting the stamped grid with electronic components to the mounting surface, which branch member is mounted on the mounting surface being substantially of the same material as the stamped gate.

An advantage of the control unit unit according to the invention is to be able to operate in a hot oil environment while offering a long service life. In addition, there will generally be no electrochemical corrosion between the connection element and the stamped grid because these two elements are practically in the same material. This is why the connection between the branch element and the stamped grid will not usually be hermetically sealed to be separated from the oil environment. In addition, in general, the location of the mechanical forces (location of the branch element) and the location of the material junction are separate locations. This is particularly the case if the stamped grid and the branch element are made of aluminum and the conductive paths of the circuit board element are made of copper. Aluminum has, in addition, in general, the advantage of chemically resisting the oil environment. Under these conditions, it is usually not necessary to separate, in a sealed manner, the aluminum stamped grid, hermetically with respect to the location of the realization of the seal. A stamped copper gate generally avoids the transition or joining of a material with another material (for example that of the conductive paths or the connecting wire) so that there will be no electrochemical corrosion due to differences electrochemical voltage of metals. In addition, usually, the replacement of the electrical connection is distinct from that where the forces or stresses are generated (location of the connection element of the connection between the branch connection and the stamped grid). The branch member may be electrically connected by a wire to the electrical components. Thus, the branching element is generally connected in a technically simple manner to the electrical components. The bonding wire may be aluminum or copper. The cable connection may be made of the same material as the branch element or in the same material as the conductive paths or the connecting wire of the circuit board element with the connecting wire or with a third material such as that, for example, gold. Instead of a connecting wire can also consider a connecting tape. The branch member is connected by a lead wire to a conductive path of the circuit board member and through the conductive paths to the electrical components. The branch member may be connected to the branch wire pad of the circuit board member by an electrical connection, the pad being at least electrically connected to one of the electrical components. This is typically a technically simple and secure connection between the branch element and the conductive paths or electrical components. The circuit board element may have internally conducting paths and the branch element has no direct electrical connection to the conductive paths. Usually, the location of the mechanical forces and / or the thermomechanical forces (location of the connection element) is decoupled or separated even more strongly from the location of the electrical connection or the connection of the conductive paths. The branching element can be connected by laser welding to the stamped grid, which is generally a solid, technically simple and fast connection solution to be made between the stamped grid and the branching element. The branching element may be in the form of a connecting lug or flat pin having a height in the direction perpendicular to the mounting surface and a length in the direction parallel to the mounting surface, the height of the connecting element being less than its length and in particular the height of the branch element being at most equal to half of its length. The advantage of this solution is that the location where the forces or mechanical or thermomechanical stresses (the junction between the stamped grid and the connection element) are generated are particularly well separated from the junction of material or replacement of the electrical connection. . The branching element can be installed parallel to the direction of the widest extension of the stamped grid which usually allows a particularly good geometrical separation between the location where the forces or mechanical and / or electromechanical stresses are generated (connection between the stamped grid and the branching element) and the location of the electrical connection.

The bonding wire can be coated with a cast mass, which guarantees the sealing of the electrical connection between the connection element and the electrical components, that is to say their separation from the oil environment. . In addition, the junction point between a material (eg aluminum on one side of the bonding wire) and another material (eg copper on the other side of the bonding wire) will be sealed in a manner technically simple and guaranteed. The cast mass may comprise an epoxy resin, polyurethane or polyacylate. The branch member may be at least partially embedded with cast mass. The advantage of this solution is that if the bonding wire is of a different material than that of the branch member, there will usually be an even better seal of the bonding element by the material on the other material.

According to another development, the subject of the invention is a method of electrically connecting a substantially copper or aluminum stamped grid to electrical components installed on the mounting surface of a circuit board element. the steps of installing a branch member on the mounting surface of the circuit board member, the branch member being substantially of the same material as the drawn gate, electrically connecting the branch member to the electrical components, encapsulate the electrical components and the area of the electrical connection between the branch element and the electrical components with the cast mass, in particular an epoxy resin, install the stamped gate on the side of the circuit board element to the opposite of the mounting surface and electrically connect the stamped grid to the branchem element ent.

The above steps can be performed in the order listed which, however, is not imperative. This means that the steps can be executed in a different order.

This method has the advantage of providing a control unit unit that has a longer service life even when operating in a hot oil environment. In addition, between the branch member and the drawn gate, there is usually no electrochemical corrosion because the two elements are practically in the same material. This is why the connection between the branch element and the stamped grid does not, in general, have to be hermetically separated from the oil environment. Moreover, in this method, the place where the mechanical or thermomechanical forces occur (locations of the branch element or the connection zone between the branch element and the stamped grid) and the location of the joint of matter are, in general, distinct. This applies in particular to the case of a stamped grid and an aluminum branch element and conductive paths of the copper circuit board element. Aluminum has the further advantage of being chemically resistant to the oil environment. This is why a stamped aluminum grate does not have to be sealed from the oil. In the case of a copper stamped grid, there will be, for example, no transition with another material (for example the material of the conductive paths or of the pad for the wire of connection) so that it n There will be no electrochemical corrosion generated by the electrochemical voltages different from the metals. In addition, and typically, replacement of the electrical connection is distinct from the location where the forces or stresses are generated (location of the branch element or the connection between the branch element and the stamped grid).

The stamped grid may be connected to the branching element by welding, in particular laser welding, of the stamped grid to the branching element. This usually allows for a strong connection in a technically simple and fast way between the stamped grid and the branch element.

The electrical connection between the branch member and electrical components by connecting the branch member to a conductive path of the circuit board member is with a lead wire. The conductive path can be electrically connected to the electrical components, thereby electrically connecting the connection element to the electrical components in a simple manner. The bonding wire may be aluminum or copper or, for example, even gold. The bonding wire may be in the same material as the branching member or in a material similar to that of the conductive paths or the bonding wire pad of the circuit board member to be connected to the bonding wire. Instead of a connecting wire can also consider a connecting tape. The branching element according to this method may be a flat pin whose height is perpendicular to the mounting surface and the length is parallel to the mounting surface, the height of the connection element being less than its length and in particular the height of the branch element is at most equal to half of its length. An advantage of this solution is that the location where the forces or mechanical or thermomechanical stresses or stresses (connections between the grid and the connection element) are generated will be particularly well separated from the material junction, that is to say from replacement of the electrical connection.

drawings

The present invention will be described hereinafter in more detail with the aid of an exemplary control unit unit with its manufacturing method shown in the accompanying drawings in which: FIG. 1 is a schematic section of an embodiment of a control unit unit according to the invention without a stamped gate, and FIG. 2 is a schematic sectional view of an embodiment of the control unit unit according to FIG. invention with the stamped gate.

In figures that are schematic and not to scale, the same references designate the same elements or elements of the same function.

Description of embodiments

FIG. 1 is a schematic sectional view of an embodiment of a control unit unit 1 according to the invention without the stamped grid 40, that is to say that the stamped grid 40 which forms part of the control unit unit 1 is not shown. FIG. 2 is a schematic cross-sectional view of an embodiment of the control apparatus unit 1 according to the invention comprising the pressed gate 40. FIG. 1 shows the circuit board element 10 and the connecting element 60 before the establishment of the stamped grid. Fig. 2 shows the control unit unit 1 after placement of the pressed grid 40 on the branch member 60 and after the casting coating of the connecting wire 70. The apparatus unit of control 1 may be the unit of a gearbox control device equipping a motor vehicle. The control unit unit 1 controls or regulates the components of a gearbox. The controller unit 1 is installed in an oil environment inside the gearbox. The control unit unit 1 comprises a circuit board element 10, for example a printed circuit board (also called PCB). The circuit board member 10 has a mounting surface 20. The mounting surface 20 (in Fig. 1 is the upper surface of the circuit board member 10) extends over the entire face upper part of the circuit board element 10 or at least a large part thereof. Electrical or electronic components 30, 31, 32 are installed on the mounting plate.

To simplify the description, by convention, the electrical or electronic components 30, 31, 32 will be referred to simply as electrical components 30, 31, 32. The circuit board unit 10 furthermore has internally conducting paths 15 and / or on the mounting surface 20, the conductive paths 15 for electrically connecting and connecting the electrical components 30, 31, 32. The conductive paths 15 are copper. Other materials such as aluminum are conceivable. The mounting surface 20 comprises at least one pad 71 for the connection of a connecting wire 70 in electrical contact with the conductive paths 15. The circuit board element 10 comprises a branch element 60. The branch element 60 may be flat (for example a flat pin). Its largest extension is parallel to the stamped grid and parallel to the mounting surface. The branch member 60 is installed on the mounting surface of the circuit board member 10 by being attached to the circuit board member 10. The branch member 60 can be glued to the mounting surface pressed against it or welded to it.

The side of the circuit board member 10 facing the mounting surface 20 (in Fig. 1 and Fig. 2 is the upper face of the circuit board member 10); on the mounting surface 20 is a stamped grid 40. The stamped grid 40 is partially coated by injection, for example with a plastic material. The stamped grid 40 does not directly or indirectly touch the circuit board element 10, but part of the encapsulation 45 of the stamped grid 40 is between the stamped grid 40 and the circuit board element 10. end of the stamped gate 40 (right end of the stamped gate 40 according to Figure 2) is electrically connected to the branch member 60. The branch member 60 is integrally connected to the stamped gate 40. The solid connection is, for example, performed by laser welding. For this, the gate grid 40 with connection element 60 is welded into the laser welding zone 50 of the stamped grid 40 or of the branching element 60. The branching element 60 is electrically connected to the stamped grid 40 or parts of it.

The stamped grid 40 serves to electrically connect the components 30, 31, 32 of the mounting surface 20 of the circuit board element 10 to other external elements of the control unit unit 1 (for example sensors or others). The stamped grid 40 has one or more electrically conductive (relatively rigid) branches obtained by stamping. The stamped gate 40 may be aluminum. Thus, the stamped gate 40 will be manufactured economically; it will be light and chemically resistant to aggression of oils. The stamped grid 40 may alternatively be made of copper. Branch member 60 has a rectangular shape. In the sections of Figures 1 and 2, the branch member 60 has a rectangular section. The branch element 60 is electroconductive. The branch member 60 has a flat shape, i.e., a height (in the up-down direction according to Figure 1 or Figure 2) which is significantly smaller than its length (from right to left). left according to Figure 1 or Figure 2).

The direction of the largest extension of the stamped grid 40 (in FIG. 2 from left to right) is parallel to the branch member 60 and also parallel to the mounting surface 20. The branch member 60 is in contact with or attached to the circuit board member 10 by one of its largest opposing surfaces (in FIG. 1 and FIG. 2 it is the bottom face of the branching element). The opposite face (the upper side of FIG. 1 and FIG. 2) of the connecting element 60 is partly connected to the stamped grid 40. A part of the branch element 60, for example about 50%, is covered by the cast mass 80. The cast mass 80 seals the electrical components with respect to the oil environment and the connecting wire 70 or the electrical connection between the connection element 60 and the electrical components 30 , 31, 32 / shoes 71 of the connecting wire, relative to the oil environment.

In the region of the branch element 60 which is not turned towards the stamped gate (right zone of FIG. 2), the shoe 71 is electrically connected to the branch element by a connecting wire 70. Thus, the stamped grid 40 is connected by the branch element 60, the connecting wire 70 and the conductive paths 15 of the circuit board element 10 to the electrical components 30, 31, 32 of the mounting surface 20 of the circuit board element 10 or parts thereof.

There may also be several connection elements on the circuit board element 10; these connection elements can be connected to the same stamped grid 40. One can also consider several connection elements each connected to a different stamped gate. The branch element 60 is not electrically connected directly or indirectly to the conductive paths 15 of the circuit board element 10 or to the electrical components 30, 31, 32. The electrical connection between the branch element 60 and the conductive paths 15 of the circuit board element 10 is made by a connecting wire (wire bond) or a connecting wire 70. For this, there is a connecting wire 70 between the right side of the circuit element. 60 of the circuit board element 10. The electrical components 30, 31, 32 may also be electrically connected to the conductive paths 15 of the circuit board element 10 by means of wires of the circuit board element 10. link 70 or be connected in a different way.

The electrical components 30, 31, 32 may be soldered or connected to the circuit board element 10.

After having installed the connecting element 60 on the mounting surface or having fixed it and making the wire connection, that is to say with the connecting wire 70 and the pad 17, the electrical components 30, 31, 32 or parts thereof and the connecting wire 70 as well as the portion of the branch member 60 will be sealed by a casting 80 (to be separated from the oil environment). The casting mass 80 may be a varnish.

As the material of the casting mass 80 is considered epoxy resin. The epoxy resin has a coefficient of thermal expansion that is equal to or very close to the coefficient of thermal expansion of the circuit board member 10. Other materials, including materials that cling to the circuit board 10 and seal the branch element 60 and the connection between the branch element 60 and the conductive paths 15 of the circuit board element 10 can also be envisaged to achieve the water tight separation. liquid (eg oil).

Part of the electrical components 30, 31, 32 may be covered in the manner of a cover 85 (for example parallel to the mounting surface 20 of the circuit board element 10) and provision may be made of a casting mass 80 on both sides of the electrical components 30, 31, 32 to also perform the hermetic seal; the electrical components 30, 31, 32 will then be in a cavity.

By sealing with the cast mass, the location of the material junction or material transition if the stamped grid 40 and consequently also the branching element 60 are made of aluminum, that is to say the joint between the aluminum and the copper will be in the casting mass 80. The material junction is thus protected by the casting mass 80 against electrochemical corrosion. The transition of material or change of material is, for example, between the branch member 60 (aluminum) and the connecting wire 70 (copper); alternatively, the material transition is between the wire 70 (aluminum) and the shoe 17 (copper).

The stamped grid 40 is at least partially coated by injection and the area of the grid intended to be connected to the connecting element 60 remains unobstructed. This applies in particular to a branch element 60 connected to the stamped grid 40 by laser welding.

The connecting wire 70 between the branch member 60 and the pad 17 or the electrically conductive paths 15 of the circuit board member 10 (i.e. there is no direct or indirect electrical connection between the branch element 60 and the conductive paths 15 of the circuit board element 10), realize the separation of the location where the mechanical and / or thermomechanical stresses are generated (in operation or when welding the stamped grid 40 to the branch member 60) and the location where the electrical connection is made. This is also true for a branch member 60 and a stamped gate 40 substantially of copper. In the case of an aluminum stamped grid 40 and a branching member 60 made of aluminum, the location of the transition between the aluminum and the material of the conductive paths 15 (which usually are not aluminum but, for example, copper) is separated from the connection between the branch member 60 and the stamped gate 40 and thus the location where the mechanical stresses are generated. In addition, there is no direct or indirect electrical connection between the stamped grid 40 and the connecting wire 70. Between the stamped grid 40 and the connecting wire 70, there is the connection element 60 which carries out the electrical connection between the stamped grid 40 and the connecting wire 70. This also avoids a weld (selective welding).

NOMENCLATURE OF THE MAIN ELEMENTS 1 Control unit 10 Circuit board element 15 Conductor path 20 Mounting surface 30, 31, 32 Electrical / electronic components 40 Pressed grid 60 Connection element 70 Connecting wire 71 Slider for wire bond 80 Mass casting 85 Cover

Claims (10)

1) A control unit unit (1) for a motor vehicle comprising: a circuit board element (10) with electrical components (30, 31, 32) installed on the mounting surface (20) thereof a circuit board member (10), and a stamped grid (40) installed on the side of the circuit board member (10) away from the mounting surface (20) for electrically connecting the components (30). 31, 32) of the mounting surface (20), the stamped gate (40) being substantially copper or aluminum, a control unit unit characterized by having a connecting element (60) electrically connecting the stamped grid (40) to the electrical components (30,31,32) of the mounting surface (20) and being installed on the mounting surface (20), the branch element (60) being substantially formed in the same material than the stamped gate (40). 2 ") control unit (1) according to claim 1, characterized in that the branching element (60) is connected by a connecting wire (70) to the electrical components (30, 31, 32). 3) A control unit unit (1) according to claim 1 or 2, characterized in that the branching element (60) is connected to the pressed grid (40) by laser welding. Control unit unit (1) according to one of claims 1 to 3, characterized in that the branching element (60) is a flat pin of height perpendicular to the mounting surface (20) and of length parallel to the mounting surface (20), the height of the connecting element (60) being less than the length of the connecting element (60) and in particular the height of the connecting element (60) is at most equal at half the length of the branch member (60). 5 ") control unit (1) according to one of claims 1 to 4, characterized in that the branch element (60) is peirallèle the direction of the greater extension of the stamped grid (40) ). 6 ") control unit (1) according to claim 2, characterized in that the connecting wire (70) is coated with a fusilated mass (80). 7) Control unit unit (1) according to one of claims 1 to 6, characterized in that the branch element (60) is at least partially wound with a casting mass (80). 8®) A method of electrically connecting a stamped gate (40) substantially of copper or aluminum to electrical components (30, 31, 32) installed on the mounting surface (20) of a circuit board member ( 10), the method characterized by the following steps: installing a branch member (60) on the mounting surface (20) of the circuit board member (10) and which is substantially of the same material as the gate pressed (40), electrically connecting the branch element (60) to the electrical components (30, 31, 32), encapsulating the electrical components (30, 31, 32) and the area of the electrical connection between the branch element (60) and the electrical components (30, 31, 32) with the casting compound (80), in particular an epoxy resin. installing the stamped grid (40) on the side of the circuit board member (10) away from the mounting surface (20), and electrically connecting the stamped grid (40) to the branch member ( 60). Method according to claim 8, characterized in that the stamped grid (40) is connected to the branching element (60) by welding, in particular laser welding of the stamped grid (40) to the element of FIG. connection (60). Process according to Claim 8 or 9, characterized in that the connection element (60) is electrically connected to the electrical components (30, 31, 32) by connecting the branch element (60) to a path conductor of the circuit board element (10) with a connecting wire (70). It ") Method according to one of claims 8 to 10, characterized in that the connecting element (60) is in the form of a flat pin having a height in the direction perpendicular to the mounting surface (20) and a length in the direction parallel to the mounting surface (20), the height of the branch member (60) being less than the length of the branch member (60) and in particular the height of the branching element (60) is at most equal to half the length of the branch element (60).