Electronics module
Patent Information
- Application Number
- EP2024702919
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-02-22
- Filing Date
- 2024-01-30
- Publication Date
- 2025-12-31
AI Technical Summary
Existing electronic modules in automotive transmissions face challenges in sealing the connection points between electrical assemblies and circuit boards, particularly when exposed to transmission fluid, as metal chips can accumulate and cause short circuits, and traditional sealing methods are complex and costly.
A potting compound with recesses and ribs is applied to the circuit board, combined with a protective assembly featuring a collar and chambers, creating a labyrinth seal that prevents metal chips from penetrating and simplifies manufacturing, using the DIM process for direct injection molding.
This solution provides reliable and cost-effective protection for electrical connection points, preventing metal shavings from reaching the contact elements and ensuring a secure seal without the need for complex components, while being suitable for both single and double-sided circuit boards.
Smart Images
Figure EP2024052129_29082024_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] title
[0003] Electronic module
[0004] State of the art
[0005] Electronic modules comprising printed circuit boards populated with electrical components are known in the prior art. Such electronic modules are installed as control modules or sensor modules in automotive engineering, for example, in the transmission. The electronic modules can have a central printed circuit board as the base for the assembly and connection technology and electrical components such as actuators, sensors, and connectors for connecting a vehicle wiring harness and an electronic control circuit. To contact the various electrical components of the electronic module, electrical components can also be used that comprise electrical conductors embedded in an insulating sheath, with the ends of the conductors extending from the insulating sheath as contact elements.Such electrical assemblies can be manufactured, for example, as overmolded leadframe parts, with the contact elements soldered directly to the circuit board or, for example, as through-hole pins that are electrically connected to the circuit board's contact holes. Since the electronic module is exposed to the transmission fluid, sealing measures are required in the area of the connection between the pins and the circuit board to prevent metal chips contained in the transmission fluid from accumulating on the pins and causing short circuits.
[0006] In this context, for example, DE 102011 085 924 A1 discloses a control module for use in a motor vehicle transmission with a printed circuit board and an electrical assembly arranged on the printed circuit board with an insulating sheath and with contact elements protruding from the insulating sheath and designed as connection pins, which are each inserted into a contact opening of the printed circuit board forming the counter contact for electrically contacting the printed circuit board and the electrical assembly.DE 102011 085 924 A1 uses a protective assembly made of electrically insulating material and referred to in this document as a centering plate, which has a base body made of plastic on which chambers separated from one another by separating ribs are formed, wherein the separating ribs are placed on the circuit board with ends projecting towards the circuit board in such a way that at least a section of each contact element of the electrical assembly is arranged in a chamber of the protective assembly, separated from the other contact elements.
[0007] Recently, an increasing number of electronic modules have been developed that use a potting compound on the circuit board to cover the electrical components on the circuit board. For example, DE102016 219 116 A1 describes a dam-fill process for producing a potting compound. More recent electronic modules use potting compounds that are applied to the circuit board using a DIM process (DIM: direct injection molding), whereby the circuit board is held in an injection mold. The potting compound is used to seal the electronic module for use in a transmission fluid. If a potting compound is used, the seal between the potting compound and the connection point of the contact elements of an electrical assembly mounted on the circuit board is important, since the connection points often cannot be covered with the potting compound itself for technical reasons and due to the assembly sequence of the modules.If protective caps are used over the connection points, the problem arises that the transmission fluid could get outside the potting compound along the edge of the protective cap to the connection points.
[0008] Disclosure of the invention
[0009] The invention relates to an electronic module, in particular a control module or sensor module for use in a motor vehicle transmission, comprising a printed circuit board, at least one electrical assembly arranged on the printed circuit board with an insulating sheath and with contact elements projecting from the insulating sheath, which contact elements are each electrically connected to a mating contact of the printed circuit board, at least one protective assembly made of electrically insulating material with at least one base body on which chambers separated from one another by separating ribs are formed, wherein the separating ribs are placed on the printed circuit board with ends projecting towards the printed circuit board in such a way that at least a section of each contact element is arranged in a chamber of the protective assembly, separate from the other contact elements.According to the invention, a potting compound is applied to the printed circuit board, wherein the potting compound has a recess exposing the mating contacts, into which the separating ribs engage, wherein the potting compound has a rib projecting towards the base body and formed from the potting compound at the edge of the recess, wherein the base body has a collar projecting towards the printed circuit board, which collar encompasses the rib with a lateral overhang.
[0010] Advantages of the invention
[0011] The invention advantageously enables inexpensive yet reliable chip protection of the electrical connection point between an electrical assembly and a circuit board provided with a potting compound, wherein the number of components of the protective assembly is low and therefore costs are saved. Instead of a complex seal, a rib is formed on the surface of the potting compound, which is overlapped by a protruding collar of a base body of the protective assembly. The rib can be easily manufactured, particularly when manufacturing the potting compound using the DIM process. There is a narrow gap between the collar and the rib, which causes multiple deflections of transmission fluid penetrating the gap between the potting compound and the protective assembly. Metal chips get stuck to the rib and are therefore unable to pass through the narrow gap.The protective assembly can be easily manufactured from plastic, for example, as an injection-molded part, whereby a base body of the protective assembly can easily be provided with a collar and, if necessary, other structures. In particular, the space between a region of the surface of the potting compound provided with the rib and a surface area provided with the collar on a side of the base body facing the potting compound can be designed as a labyrinth seal. Penetrating metal chips advantageously remain trapped in the labyrinth and do not penetrate to the contact elements.The contact elements of the electrical assembly can be soldered onto a surface of the printed circuit board or, for example, as connection pins in through-hole mounting, electrically contacted and soldered to contact openings in the printed circuit board, whereby in the first case the protective assembly can be designed, for example, in one piece on only one side of the printed circuit board and in the second case on both sides and, for example, in two parts.
[0012] Advantageous embodiments and further developments of the invention are made possible by the features contained in the dependent claims.
[0013] The invention is particularly advantageously suitable for an electronic module with a printed circuit board populated on both sides, in which the printed circuit board has a first side and a second side facing away from it, the electrical assembly is arranged on the first side and the contact elements of the assembly are designed as connection pins which are each led from the first side through contact openings in the printed circuit board provided as mating contacts to the second side, wherein ends of the contact elements protrude from the second side.
[0014] In this case, the potting compound can have a first potting compound portion applied to the first side and a second potting compound portion applied to the second side, wherein the first potting compound portion has a first recess on the first side in the region of the contact openings and a first rib at the edge of the first recess, and wherein the second potting compound portion has a second recess on the second side in the region of the contact openings and a second rib at the edge of the second recess. The protective assembly advantageously comprises a first cover element arranged on the first side of the circuit board and covering the first recess, and a second cover element arranged on the second side of the circuit board and covering the second recess.The first cover element preferably has a first base body on which a first collar overlapping the first rib and first chambers separated from one another by first separating ribs are formed, wherein the first separating ribs are placed on the first side of the circuit board in the first recess, wherein the second cover element has a second base body on which a second collar overlapping the second rib and second chambers separated from one another by second separating ribs are formed, wherein the second separating ribs are placed on the second side in the second recess.
[0015] Since the electrical assembly is arranged on the first side and not on the second side, the second rib on the second side can particularly advantageously also be formed circumferentially around the second recess and can be circumferentially overlapped by the second collar.
[0016] The two-part design of the protective assembly with two cover elements advantageously ensures that a section of the contact elements protruding directly from the insulating sheath is accommodated in each of the first chambers, and one end of a contact element is accommodated in each of the second chambers. This provides reliable protection even for contact elements arranged in through-hole mounting on the circuit board and that must be reliably protected on the first and second sides of the circuit board. In particular, it is possible for the first cover element and the second cover element to be positioned opposite each other with respect to the circuit board.
[0017] To fasten the cover elements, the circuit board can have at least one opening, and at least one pin can be formed on the second cover element, which pin extends through the opening and engages in a receiving opening of the first cover element. Alternatively or additionally, at least one pin can be formed on the first cover element, which pin extends through the opening and engages in a receiving opening of the second cover element. The pin can be firmly anchored in the receiving opening, for example by a welding process or hot caulking, so that a section of the circuit board is clamped between the first cover element and the second cover element. As a result, the ends of the first separating ribs and the second separating ribs can be pressed against the first side and the second side of the circuit board, respectively, thereby enabling particularly good sealing of the first chambers and the second chambers.
[0018] Short description of the drawings
[0019] Possible embodiments of the invention are explained below with reference to the accompanying figures. The drawings show:
[0020] Figure 1 is a perspective view of a partial view of a first embodiment of an electronic module according to the invention along a first sectional plane through the electronic module,
[0021] Figure 2 is a cross-sectional view of the electronic module of Figure 1,
[0022] Figure 3 shows a further perspective view of a partial view of the electronic module according to the invention along a second sectional plane perpendicular to the first plane through the electronic module of Figure 1.
[0023] Embodiments of the invention
[0024] Figure 1 shows a perspective view of an exemplary embodiment of an electronic module 1 according to the invention along a first sectional plane through the electronic module. Only a partial section of the entire electronic module 1 is visible. The electronic module 1 has a printed circuit board 2, which is provided on one or both sides with electronic components not shown in Figure 1. The printed circuit board 2 can be a multilayer printed circuit board with conductor tracks routed on the inner layers, which are interconnected by electrical interconnectors and / or vias. The electronic components can form a control circuit, for example, for a transmission of a motor vehicle.In addition, connector assemblies for connecting to a cable assembly, sensors and other electrical assemblies can be arranged on the electronic module, which serve, for example, to electrically connect a pump control module or to electrically connect electro-hydraulic actuators.
[0025] The electronic module in Figure 1, for example, has an electrical assembly 3, which has an overmolded lead frame part with an insulating sheath 32. The electrical assembly 3 serves to connect an electrical component (not shown) to the printed circuit board 2. Contact elements 31, which serve to connect to the printed circuit board 2, are led out laterally from the insulating sheath 32 and contacted with mating contacts 25 of the printed circuit board 2. The electrical assembly 3 is placed on a first side 21 of the printed circuit board. Furthermore, a potting compound 5 is applied to the first side 21. The potting compound 5 preferably comprises a thermosetting material, for example an epoxy resin, and is applied to areas of the first side 21 using the DIM process (DIM: direct injection molding).The potting compound 5 has a recess 52, at least in the area of the mating contacts 25 of the circuit board 2, in which recess 52 the mating contacts 25 of the circuit board are exposed. Unlike what is shown in Figure 1, the mating contacts 25 can, for example, be designed as contact surfaces to which the contact elements 31 are soldered. In the right-hand area of Figure 1, the recess 52 is sufficiently large to allow the electrical assembly team 3 to approach the mating contacts 25. The potting compound 5 has a projecting rib 56 at the edge of the recess 52 on its surface 50 facing away from the circuit board 2.
[0026] A protective assembly 4 comprises, for example, two cover elements 4a and 4b made of electrically insulating material, in particular plastic, of which a first cover element 4a is initially considered in Figure 1, which covers the recess 52 in Figure 1. The first cover element 4a has a base body 41 on which chambers 44 separated from one another by separating ribs 42 are formed. The separating ribs 42 are placed on the circuit board 2 with ends projecting toward the circuit board 2 in such a way that at least a portion of each contact element 31 is arranged in a chamber 44 of the protective assembly 4, separate from the other contact elements 31. The base body 41 is plate-shaped and flat on the side facing away from the printed circuit board, wherein the base body 41 projects with its edge laterally beyond the chambers 44 and covers both the rib 56 and an end section of the insulation sheath 32 of the electrical assembly 3.The base body 41 has, at least above the potting compound 5, a collar 43 which projects towards the circuit board 2 and encloses the rib 56 with a lateral projection. This creates a narrow gap, or rather a narrow, winding intermediate space, between a region of the surface 50 of the potting compound 5 provided with the rib 56 and a surface region 48 provided with the collar 43 on a side of the base body 41 facing the potting compound 5, which surface region is designed as a labyrinth seal 49. In addition, the collar 43 can cover the insulating sheath 32 on a side of the recess 52 opposite the rib 56 and likewise form a labyrinth seal there. On this side, the base body 41 is separated from the insulating sheath 32 by a groove 48 shown in Fig.2 spaced apart by a narrow gap marked with the arrow 39, wherein a further rib 60 and the collar 43, which is preferably formed circumferentially on the base body 41, project from the base body 41 in the direction of the insulation sheath 32.
[0027] In a first embodiment of the invention, it can be provided that the contact elements 31 are not arranged in a through-hole assembly, as shown, but are soldered flat onto mating contacts on the first side of the printed circuit board 2. The protective assembly 4 can then have only a single cover element, for example, the cover element 4a, since protection on the opposite second side 22 is then not required.
[0028] In a particularly advantageous second embodiment, however, the contact elements 31 are arranged as connection pins in through-hole mounting in mating contacts 25 of the circuit board 2, which are designed as contact openings 26, wherein a section of the contact elements 31 emerging directly from the insulating sheath 32 is arranged on the first side 21 and an end 33 of the contact elements 31 is arranged on the second side 22, as can be seen in Figures 2 and 3. The contact elements 31 can be soldered in the contact openings 26.
[0029] As further shown in Figure 2, the potting compound 5 can have a first potting compound portion 5a applied to the first side 21 and a second potting compound portion 5b applied to the second side 22. The first potting compound portion 5a and the second potting compound portion 5b can both be produced on the printed circuit board 2 during the same DIM process. The first potting compound portion 5a can, for example, have at least one first recess 52a on the first side 21 in the region of the contact openings 26 and a first rib 56a at the edge of the first recess 52a. The first rib 56a is not circumferential, since the electrical assembly 3 rests on the first side 21 opposite the edge of the first recess 52a.
[0030] The second encapsulant portion 5b has a second recess 52b on the second side 22 in the region of the contact openings 26 and a second rib 56b at the edge of the second recess 52b. The second rib 56b can preferably be formed circumferentially around the second recess 52b. This is possible on the second side 22 since the electrical assembly 3 does not rest there.
[0031] As further shown in Figure 2, the protective assembly 4 has a first cover element 4a arranged on the first side 21 of the circuit board 2 and covering the first recess 52a, and a second cover element 4b arranged on the second side 21 of the circuit board 2 and covering the second recess 52b. The first cover element 4a comprises a first base body 41a, on which a first collar 43a overlapping the first rib 56a and first chambers 44a separated from one another by first separating ribs 42a are formed. The first separating ribs 42a are placed in the first recess 52a on the first side 21 of the circuit board 2. The second cover element 4b has a second base body 41b, on which a second collar 43b overlapping the second rib 56b and second chambers 44b separated from one another by second separating ribs 42b are formed, wherein the second separating ribs 42b are placed on the second side 22 in the second recess 52.The second collar 43b is formed like the second rib 56a circumferentially around the second recess 52b and can therefore circumferentially overlap the second rib 56a.
[0032] In the arrangement in Figure 2, a section of the contact elements 31 emerging directly from the insulating sheath 32 can be accommodated in each of the first chambers 44a, while an end 33 of the contact element 31 is accommodated in each of the second chambers 44b. Figure 3 shows a further perspective view of the electronic module 1 along a second sectional plane through the electronic module, perpendicular to the sectional plane of Figure 2. In Figure 3, the plurality of first chambers 44a and the opposite second chambers 44b are clearly visible. It can also be seen that the first cover element 4a and the second cover element 4b are opposite one another with respect to the circuit board 2.
[0033] Figure 3 also shows that the circuit board 2 has two openings 24 within the area exposed by the first cutout 4a and the second cutout 4b. For example, on the second cover element 4b, two pins 46 are formed, each passing through the openings 24 and each engaging in a receiving opening 47 of the first cover element 4a. However, it is also possible to provide only one pin or more than two pins, which engage in a corresponding number of receiving openings. It is understood that the pins can also be formed on the first cover element 4a, each engaging in receiving openings 47 of the second cover element 4b. The pins 46 can be firmly anchored in the receiving opening 47 by hot caulking or in another way, so that a section of the circuit board 2 is clamped between the first cover element 4a and the second cover element 4b.As a result, the ribs 42a are pressed against the first side 21 and the ribs 42b are pressed against the second side 22 of the circuit board, so that the first chambers 44a and the second chambers 44b are all sealed from one another.
Claims
Claims 1. An electronic module (1), in particular a control module or sensor module for use in a motor vehicle transmission, comprising a printed circuit board (2), at least one electrical assembly (3) arranged on the printed circuit board (2) with an insulating sheath (32) and with contact elements (31) projecting from the insulating sheath (32), each of which is electrically connected to a mating contact (25) of the printed circuit board (2), at least one protective assembly (4) made of electrically insulating material with at least one base body (41) on which chambers (44) separated from one another by separating ribs (42) are formed, wherein the separating ribs (42) are placed on the printed circuit board (2) with ends projecting towards the printed circuit board (2) in such a way that at least a portion of each contact element (31) is arranged in a chamber (44) of the protective assembly (4) separated from the other contact elements (31), characterized in thatthat a potting compound (5) is applied to the circuit board (2), wherein the potting compound (5) has a recess (52) exposing the mating contacts (25) and into which the separating ribs (42) engage, wherein the potting compound (5) has, at the edge of the recess (52), a rib (56) projecting towards the base body (41) and formed from the potting compound (5), wherein the base body (41) has a collar (43) projecting towards the circuit board (2) and enclosing the rib (56) with a lateral overhang.
2. Electronic module according to claim 1, characterized in that an intermediate space between a region of the surface (50) of the potting compound (5) provided with the rib (56) and a surface region (48) provided with the collar (43) on a side of the base body (41) facing the potting compound (5) is designed as a labyrinth seal (49).
3. Electronic module according to one of the preceding claims, characterized in that the printed circuit board (2) has a first side (21) and a facing away from the second side (22), in that the electrical assembly (3) is arranged on the first side (21) and the contact elements (31) of the assembly (3) are designed as connection pins, which are each led from the first side (21) through contact openings (26) provided as counter contacts (25) in the printed circuit board (2) to the second side (22), wherein ends (33) of the contact elements (31) protrude from the second side (22).
4. Electronic module according to claim 3, characterized in that the potting compound (5) has a first potting compound portion (5a) applied to the first side (21) and a second potting compound portion (5b) applied to the second side (22), wherein the first potting compound portion (5a) has a first recess (52a) on the first side (21) in the region of the contact openings (26) and a first rib (56a) at the edge of the first recess (52a), and wherein the second potting compound portion (5b) has a second recess (52b) on the second side (22) in the region of the contact openings (26) and a second rib (56b) at the edge of the second recess (52b), and in that the protective assembly (4) has a first cover element arranged on the first side (21) of the printed circuit board (2) and covering the first recess (52a). (4a) and a second cover element (4b) arranged on the second side (21) of the printed circuit board (2) and covering the second recess (52b).
5. Electronic module according to claim 4, characterized in that the first cover element (4a) has a first base body (41a) on which a first collar (43a) overlapping the first rib (56a) and first chambers (44a) separated from one another by first separating ribs (42a) are formed, wherein the first separating ribs (42a) are placed on the first side (21) of the circuit board (2) in the first recess (52a), wherein the second cover element (4b) has a second base body (41b) on which a second collar (43b) overlapping the second rib (56b) and second chambers (44b) separated from one another by second separating ribs (42b) are formed, wherein the second separating ribs (42b) are placed on the second side (22) in the second recess (52).
6. Electronic module according to claim 5, characterized in that at least the second rib (56b) extends circumferentially around the second recess (52b) and is circumferentially overlapped by the second collar (43b).
7. Electronic module according to one of claims 5 or 6, characterized in that in each of the first chambers (44a) a section of the contact elements (31) emerging directly from the insulating sheath (32) is accommodated and in each of the second chambers (44b) an end (33) of a contact element (31) is accommodated.
8. Electronic module according to one of claims 4 to 7, characterized in that the first cover element (4a) and the second cover element (4b) are opposite one another with respect to the printed circuit board (2).
9. Electronic module according to one of claims 4 to 8, characterized in that the circuit board (2) has at least one opening (24) and that at least one pin (46) passing through the opening (24) is formed on the second cover element (4b), which pin engages in a receiving opening (47) of the first cover element (4a), and / or that at least one pin (46) passing through the opening (24) is formed on the first cover element (4a), which pin engages in a receiving opening (47) of the second cover element (4b).
10. Electronic module according to claim 9, characterized in that the pin (46) is firmly anchored in the receiving opening (47) so that a section of the circuit board (2) is clamped between the first cover element (4a) and the second cover element (4b).