Electronic modules

Abstract

The present invention relates to an electronic module 1 having a circuit board 10, the circuit board having a loading side, on which a first structural element 8 and a contact element 3 are arranged. The first structural element 8 is encased in a protective material 9 on the loading side. The contact element 3 is partially embedded in the protective material 9 so that a second surface 32 of the contact element 3 protrudes naked from the protective material 9. A second structural element 4 is fixed to the contact element 3 and is electrically connected to the circuit board 10 via the contact element. The contact element 3 is inserted into a first recess 44 on a side 42 of a plastic sheath 49 of the second structural element 4 that faces the circuit board 10 so that the second surface 32 of the contact element 3 abuts against a connecting section 51 of the second structural element 4.

Description

Technical Field

[0001] The invention relates to an electronic module. Background Art

[0002] Known electronic modules are provided with an electronic control circuit with electrical components for processing signals and power components, as well as sensors and plugs. The electronic module can also be installed in a motor vehicle as a transmission control module and there exposed to the hydraulic oil of the motor vehicle transmission and to temperatures between -40° C. and 150° C. In recent years, electronic modules have been developed that use protective materials that cover components on the circuit board. Since plugs and sensors also come into contact with components outside the electronic module, these must be arranged outside the protective material or protrude from it.

[0003] DE 10 2017 210 176 A1 discloses an electronic module having a circuit board and a first structural element, which is arranged on the loading side of the circuit board and electrically contacts the circuit board. The contact element has a first surface and a second surface facing away from the first surface, the contact element is arranged on the circuit board with the first surface and electrically contacts the circuit board. The first structural element is encased in a protective material arranged on the loading side of the circuit board. The contact element is only partially embedded in the protective material, so that the side edge of the contact element is at least partially covered by the protective material around it, while the second surface of the contact element protrudes naked from the protective material. A second structural element is fixed to the contact element and is electrically connected to the circuit board via the contact element, wherein the second structural element has at least one electrical connection conductor, which is embedded in the plastic sheath and has a connection section, which is oriented parallel to the second surface of the contact element and is electrically connected to the contact element.

[0004] For this purpose, the plastic sheathing of the second component has a first recess on its side facing the circuit board. The contact element is inserted into the first recess in such a way that a second surface of the contact element rests against the connecting section. Summary of the invention

[0005] The invention relates to an electronic module having the features of the preamble of claim 1. According to the invention, it is proposed that the printed circuit board has a through-hole on a second side facing away from the load side, through which the surface of the contact element facing the load side is accessible.

[0006] Furthermore, the invention relates to a method for producing an electronic module, the method comprising the following steps:

[0007] - providing a circuit board, the circuit board comprising: a first structural element, the first structural element being arranged on a loading side of the circuit board and being in electrical contact with the circuit board; a contact element, the contact element having a first surface and a second surface facing away from the first surface, the contact element being arranged on the circuit board with the first surface and being in electrical contact with the circuit board; a protective material, the protective material being arranged on the loading side of the circuit board and the protective material enveloping the first structural element, wherein the contact element is partially embedded in the protective material so that a side edge of the contact element is at least partially covered by the protective material all around, and the second surface of the contact element protrudes bare from the protective material;

[0008] - providing a second component, wherein the second component has at least one electrical connecting conductor embedded in a plastic sheathing and having a connecting section, wherein the plastic sheathing of the second component has a first recess on its side facing the printed circuit board, through which the connecting section of the second component is accessible;

[0009] - placing the second structural element on the contact element in such a way that the connecting section is oriented parallel to the second surface of the contact element and inserting the contact element into the first recess until the second surface of the contact element bears against the connecting section;

[0010] - and soldering the contact element to the connecting section. According to the invention, it is proposed that the circuit board has a through hole on a second side facing away from the loading side, through which the surface of the contact element facing the loading side is accessible, and the contact element is soldered to the connecting section by means of a soldering device inserted into the through hole.

[0011] In the sense of the present invention, in addition to the at least one first structural element, another first structural element can also be applied, in addition to the at least one contact element, another contact element can also be applied, and in addition to the at least one second structural element, another second structural element can also be applied to the circuit board. Here, a contact element or a plurality of contact elements can be assigned to each individual second structural element. Preferably, two contact elements are assigned to each second structural element. The contact elements can be constructed as the same type or different types. The second structural element can, for example, have at least two electrical connection conductors, which are electrically connected to the assigned contact elements.

[0012] For the electronic module known from DE 10 2017 210 176 A1, a second structural element is constructed and mounted from the loading side of the circuit board, which second structural element can be, for example, a rotation speed sensor or a position sensor. The second structural element is welded together with the contact element, wherein the welding process is carried out on the loading side through a second recess provided on the side of the plastic sheath of the second structural element facing away from the circuit board. For this purpose, a free access for a welding tool is required on the loading side of the circuit board. However, since the free space on the circuit board is occupied by the second structural element and, if necessary, other structural elements of the same or different type, difficulties arise when establishing a welding connection due to the limited space.

[0013] The electronic module according to the invention advantageously enables an easy and cost-effective connection between the second component and the circuit board, wherein the second component can be mounted and fixed not only via the loading side of the circuit board, but also via the second side of the circuit board facing away from the loading side. For this purpose, the circuit board has a through hole on the second side facing away from the loading side, through which the surface of the contact element facing the loading side can be accessed. A welding tool can be placed on this surface, for example by means of a laser or a welding electrode to couple in the energy required for welding.

[0014] The contact element can advantageously be soldered, for example, to the loading side of the circuit board. This can be done, for example, cost-effectively by means of an SMD process (Surface Mounting Device) using a reflow soldering method. Preferably, this is done in parallel with the process of mounting the first component on the loading side, for example using a common reflow soldering method. Immediately after the soldering process, the protective material can be applied to the loading side of the circuit board.

[0015] The second structural element can be constructed in one piece and applied to the circuit board after the application and curing of the protective material. The electronic module can be constructed relatively flat after the application of the protective material and can be processed better in an automated production device. The second structural element is constructed, for example, as a sensor dome and protrudes to a greater extent from the manufactured electronic module, and can be fixed to the electronic module after the application of the protective material. For this purpose, a welding method can now also be used advantageously on the second side of the circuit board facing away from the loading side.

[0016] Advantageous embodiments and developments of the invention are achieved by the features contained in the dependent claims.

[0017] Particularly advantageous is an embodiment in which the contact element has an internal recess on its first surface that is adjacent to the through hole. This internal recess can be configured as a blind hole, for example. The internal recess ends at an end face facing away from the second surface of the contact element, starting from the first surface of the contact element in a direction perpendicular to the loading side of the circuit board. This end face can form the face of the contact element facing the loading side in a simple manner. During welding, for example, a laser beam or a welding electrode can couple energy into the end face through the through hole and the internal recess, whereby the end face is melted and can be welded to the connecting section from the second side of the circuit board.

[0018] Furthermore, the plastic sheath of the second component may additionally have a second recess on its side facing away from the circuit board, through which the connecting section of the second component is accessible. Such a second recess, which is known per se from DE 10 2017 210 176 A1, allows, in combination with the through-hole described here on the second side of the circuit board, for example, the use of a cost-effective resistance welding method, in which a first welding electrode can be inserted into the second recess and a second electrode into the through-hole for welding the contact element to the connecting section.

[0019] The resistance welding method is particularly advantageous in combination with a welding projection arranged between the connecting section and the second surface. This welding projection can be formed, for example, on the connecting section or on the second surface of the contact element.

[0020] The contact element can preferably be formed from metal, so that laser welding methods or resistance welding methods can be carried out without problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] in:

[0022] Figure 1 shows a cross section through a first exemplary embodiment of an electronic module according to the invention;

[0023] Figure 2 shows a partial cross section through a second exemplary embodiment of an electronic module according to the invention;

[0024] Figure 3 shows a cross section through a third exemplary embodiment of an electronic module according to the invention;

[0025] Figure 4 A partial cross section through a fourth exemplary embodiment of an electronic module according to the invention is shown. DETAILED DESCRIPTION

[0026] Figure 1 A cross section through an electronic module 1 is shown. The electronic module can be, for example, part of a transmission control mechanism of a motor vehicle and be exposed to the hydraulic fluid of the transmission. However, it is also possible to use the electronic module as a controller for actuating other assemblies. The electronic module 1 has a circuit board 10, which has a first side surface provided as a loading side 11 and a second side surface 12 facing away from the first side surface. The circuit board 10 can be designed, for example, as a glass fiber reinforced epoxy resin substrate, such as an FR4 circuit board or a circuit board with a higher value. Electrical components of the control circuit are arranged on the loading side 11 of the circuit board 10, in which electrical components are arranged a first side surface 12 provided for loading. Figure 1 Only one first component 8 is shown in FIG. The first component 8 can be electrically connected to the contact area 5 arranged on the load side 11 of the circuit board via conductor tracks (not shown) of the circuit board 10 .

[0027] A protective material 9 is arranged on the loading side 11 of the circuit board 10, which surrounds the first structural element 8. The protective material can be a polymeric protective material, in particular a thermosetting plastic and in particular includes an epoxy resin, which adheres well to the circuit board 10. The protective material 9 can be applied to the circuit board in particular as a so-called HCD (hard cover dispense). This can be carried out in a dam-fill method, in which a surrounding dam consisting of, for example, a thixotropic adhesive is first applied to the circuit board and a flowable filler is subsequently injected into the area surrounded by the dam in order to cover the structural element with the protective material.

[0028] The contact element 3 is placed on the contact surface 5. The contact element 3 is made of metal and has a first surface 31 and a second surface 32 facing away from the first surface, as well as a side edge 34. The protective material 9 covers the side edge 34 of the contact element 3 all around. However, the contact element 3 protrudes from the protective material 9 with the second surface 32 and with the part of the side edge 34 adjoining the second surface 32. The contact element 3 can be welded or soldered (for example using SMD technology) to the contact surface 5 with the first surface 31.

[0029] If you can Figure 1 As can be seen in FIG. 1 , the printed circuit board 10 has through-holes 60 on the second side 12 below the contact elements 3. Each through-hole 60 can be designed, for example, as a simple through-hole in the printed circuit board 1 with a preferably circular cross section. The through-hole 60 is provided with a contact surface 5 circumferentially on the load side 11. The contact element 3 is soldered or welded to this contact surface 5 with the first surface 31. The contact element 3 can be, for example, Figure 1The contact element 3b in the left part of the embodiment is provided with a cylindrical outer side in a relatively thick-walled manner or as Figure 1 The contact element 3a on the right side of the contact surface 5 is also provided in a cap-shaped manner with a thinner wall than the contact element 3b and a flange connected to the contact surface 5. The contact element 3a can be made of a metal sheet as a deep-drawn part, for example. Figure 1 , two contact elements 3 are shown mounted on a circuit board 10. However, it is also possible to mount only a single contact element or three or more contact elements 3 on the circuit board.

[0030] exist Figure 1 In the embodiment shown, each of the contact elements 3a, 3b shown has an inner recess 61 on its first surface 31, which adjoins the assigned through-hole 60 of the circuit board 1. The inner recess 61 is configured, for example, as a blind hole. The inner recess 61 ends in a direction perpendicular to the loading side 11 of the circuit board 10 and from the first surface 31 at an end face 62 facing away from the second surface 32 of the contact element. The end face 62 forms a face 63 of the contact element 3 facing the loading side 11. This face 63 preferably extends parallel to the second surface 32 at a distance of, for example, 1 or 2 millimeters.

[0031] The second structural element 4 can be, for example, a sensor, in particular a rotational speed sensor, or an electrical connector or another electrical component. The second structural element 4 has at least one electrical connection conductor 50, which is introduced into the plastic sheath 49. The plastic sheath can be, for example, an injection molded part. Figure 1 In the embodiment, the second structural element 4 has two connecting conductors 50. The plastic sheath 49 of the second structural element 4 can have a base plate 40, from which a projection 43 on a side 41 facing away from the circuit board 10 protrudes. The base plate 40 has a first side 42 facing the circuit board 10 and a second side 41 facing away from the circuit board 10. Figure 1 Only a part of the projection 43 can be seen in the figure. For example, a sensor element or a plug-in connector encapsulated in a plastic sheath can be arranged on the end section of the projection 43. The electrical connection conductor 50 is arranged in the projection 43 perpendicular to the circuit board 10. The connection sections 51 of the connection conductor 50 are each bent at a right angle so that they extend parallel to the circuit board 10. The two connection sections 51 are bent in opposite directions and embedded in the base plate 40 of the plastic sheath 49.

[0032] The plastic sheathing 49 of the second structural element 4 has a first recess 44 on the first side 42, through which the connecting section 51 of the second structural element 4 can be accessed. The recess 44 can be in the form of a blind hole, for example. The corresponding connecting section 51 is located at the bottom of each recess 44, or the connecting section 51 is exposed there.

[0033] The contact element 3 is inserted with the second surface 32 into the recess 44 in such a way that the second surface 32 bears flatly against the surface of the connecting section 51 facing the circuit board. Figure 1 In the embodiment of the present invention, the plastic sheath 49 additionally has a second recess 45 on the opposite side 41 of the connecting section 51. The edge of the second recess 45 can be surrounded by a flange 46. The second recess 45 is used to manufacture the electronic module and can be filled with a protective material after the electronic module is manufactured to prevent metal chips of the transmission oil from entering the second recess 45 during the operation of the electronic module 1.

[0034] exist Figure 2 A second embodiment is shown in FIG. Figure 2 The examples in Figure 1 The exemplary embodiment differs only in that the plastic encapsulation 49 has no second recess 45 on the side 41 of the connecting section 51 which is opposite the contact element 3 and is designed as a closed structure.

[0035] In order to fix the second structural element 4 on the contact element 3, the second structural element 4 is placed on the contact element 3 in such a way that each of the connecting sections 51 is oriented parallel to the second surface 32 of the assigned contact element 3. Here, each contact element 3 is inserted into the assigned first recess 44 until the second surface 32 of the contact element 3 abuts against the connecting section 51. Subsequently, the contact element 3 and the connecting section 51 are welded together by means of a laser beam 100 entering the through-hole 60. Here, the laser beam penetrates into the through-hole 60 and the inner recess 61 on the second side 12 of the circuit board and illuminates the end face 62, which is thereby melted and connected to the connecting section 51. The second recess 45 is at Figure 1 In the embodiment of , it is provided to prevent the plastic above the connecting section 51 from melting.

[0036] However, slight melting of the plastic can also be tolerated. Figure 2 The second recess 45 is also omitted.

[0037] exist Figure 3 A third embodiment of the electronic module 1 according to the invention is shown in FIG. Figure 3In the embodiment, the contact element 3 is constructed as a solid base piece 3c made of metal. In this embodiment, the first surface 31 of the contact element 3 is exposed at the through-hole 60 and thus forms a surface 63 of the contact element 3 facing the loading side 11, on which a welding tool can be placed. On the opposite side of the contact element 3, the connecting section 51 is flatly abutted against the second surface 32 of the contact element 3. In this embodiment, a second recess 45 is provided on the side of the connecting section 51 opposite to the contact element 3, through which the connecting section 51 of the second structural element 4 can be approached. In this embodiment, the electrical contact between the connecting section 51 and the contact element 3 is carried out by a resistance welding method. For this purpose, the first electrode 102 of the resistance welding device is inserted into the second recess 45 and the second electrode 101 is inserted into the through-hole 60. The first electrode 102 is directly placed on the first surface 31 of the contact element 3. The current flowing from the first electrode 101 to the second electrode 102 melts the joint, so that the connecting section 51 is welded to the respectively associated contact element 3 .

[0038] exist Figure 4 An extension of this embodiment is shown in FIG. Figure 3 The difference is that in Figure 4 In addition, a welding projection 64 is provided between the connecting section 51 and the second surface 32 of the contact element 3. Due to its small wire cross section, this welding projection has an increased resistance in the resistance welding method and therefore melts more quickly. The welding projection 64 can be formed on the connecting section 51 or on the second surface 32. Figure 4 In FIG. 1 , the welding projection in the left part is designed as a stub on the surface 32 of the contact element 3 . Figure 4 In the right part of FIG. 5 , the welding projection 64 is formed on the connecting section 51 by deep drawing.

[0039] it goes without saying, Figures 1 to 4 The embodiments are not exclusive of one another and can also be used mixedly in the electronic module 1 .

Claims

1. An electronic module (1) having Circuit board (10), a first structural element (8) which is arranged on the loading side (11) of the circuit board (10) and is in electrical contact with the circuit board, a contact element (3), which has a first surface (31) and a second surface (32) facing away from the first surface (31), and is arranged on the circuit board (10) with the first surface (31) and is in electrical contact with the circuit board, a protective material (9) which is arranged on the loading side (11) of the circuit board (10) and which encloses the first structural element (8), wherein the contact element (3) is partially embedded in the protective material (9) in such a way that a side edge (34) of the contact element (3) is at least partially covered by the protective material (9) all around and a second surface (32) of the contact element (3) protrudes bare from the protective material (9), a second structural element (4) which is fixed to the contact element (3) and is electrically connected to the circuit board (10) via the contact element, wherein the second structural element (4) has at least one electrical connection conductor (50) which is embedded in the plastic sheath (49) and has a connection section (51) which is oriented parallel to the second surface (32) of the contact element (3) and is electrically connected to the contact element (3), The plastic sheath (49) of the second component (4) has a first recess (44) on its side (42) facing the circuit board (10), and the contact element (3) is inserted into the first recess (44) in such a way that the second surface (32) of the contact element (3) abuts against the connecting section (51), It is characterized in that The circuit board (10) has a through hole (60) on a second side (12) facing away from the loading side (11), through which a surface (63) of the contact element (3) facing the loading side (11) is accessible. The contact element (3) has an inner cavity (61) on its first surface (31) which is adjacent to the through hole (60).

2. The electronic module according to claim 1, characterized in that: The inner recess (61) is designed as a blind hole.

3. The electronic module according to claim 1 or 2, characterized in that: The inner gap (61) starts from the first surface (31) in a direction perpendicular to the loading side (11) of the circuit board (10) and ends at an end face (62) facing away from the second surface (32) of the contact element, and the end face (62) at least partially forms a surface (63) of the contact element (3) facing the loading side (11).

4. The electronic module according to claim 1, characterized in that: The plastic sheathing (49) of the second component (4) has a second recess (45) on its side (41) facing away from the printed circuit board (10), through which a connecting section (51) of the second component (4) is accessible.

5. The electronic module according to claim 1, characterized in that: A welding projection (64) formed on the connecting section (51) or on the second surface (32) is arranged between the connecting section (51) and the second surface (32).

6. The electronic module according to claim 1, characterized in that: The contact element (3) is made of metal.

7. The electronic module according to claim 1, characterized in that: The electronic module (1) is part of a transmission control system of a motor vehicle.

8. A method for manufacturing an electronic module, comprising the following steps: - providing a circuit board (10), the circuit board (10) having: a first structural element (8), the first structural element being arranged on a loading side (11) of the circuit board (10) and being in electrical contact with the circuit board; A contact element (3), the contact element having a first surface (31) and a second surface (32) facing away from the first surface (31), and the contact element is arranged on the circuit board (10) with the first surface (31) and is in electrical contact with the circuit board; a protective material (9) which is arranged on the loading side (11) of the circuit board (10) and which encloses the first structural element (8), wherein the contact element (3) is partially embedded in the protective material (9) such that a side edge (34) of the contact element (3) is at least partially covered around the protective material (9) and a second surface (32) of the contact element (3) protrudes bare from the protective material (9); - providing a second component (4), wherein the second component (4) has at least one electrical connection conductor (50) embedded in a plastic sheath (49) and having a connection section (51), wherein the plastic sheath (49) of the second component (4) has a first recess (44) on its side (42) facing the printed circuit board (10), through which the connection section (51) of the second component (4) is accessible; - placing the second structural element (4) on the contact element (3) in such a way that the connecting section (51) is oriented parallel to the second surface (32) of the contact element (3), and inserting the contact element (3) into the first recess (44) until the second surface (32) of the contact element (3) abuts against the connecting section (51); and welding the contact element (3) and the connecting section (51) together, It is characterized in that the circuit board (10) has a through hole (60) on the second side (12) facing away from the loading side (11), through which the surface (63) of the contact element (3) facing the loading side (11) can be approached, and the contact element (3) and the connecting section (51) are soldered together with the aid of a soldering device (100) inserted into the through hole, wherein the contact element (3) has an internal gap (61) adjacent to the through hole (60) on its first surface (31).

9. The method according to claim 8, characterized in that In the welding step, a laser welding method is used.

10. The method according to claim 8, characterized in that The plastic sheath (49) of the second structural element (4) has a second recess (45) on its side (41) facing away from the circuit board (10), through which the connecting section (51) of the second structural element (4) is accessible, and in the welding step a resistance welding method is used, in which a first electrode (102) is inserted into the second recess (45) and a second electrode (101) is inserted into the through-hole (60).

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