Partially extrusion-coated electronics component with a lost seal, method for producing an electronics component, use of the electronics component, and motor vehicle

Abstract

The invention relates to an electronics component (EB) for a motor vehicle (KFZ), comprising a printed circuit board (LP) with a top side (OS), an electrically conductive conducting element (LE) being arranged on and / or in the top side (OS), a frame element (RE), which is designed to spring back in the region of the conducting element (LE) and provides sealing against the conducting element (LE) via a sealing element (DE), being mounted on the top side (OS), the sealing element (DE) having a lower stiffness than the frame element (RE), and the top side (OS) and the frame element (RE) being potted and / or extrusion-coated in sections by an overmould material (OMM).

Description

[0001] Description

[0002] Partially overmolded electronic component with lost seal, method for producing an electronic component, use of the electronic component, and motor vehicle

[0003] The invention relates to a partially overmolded electronic component with a printed circuit board, wherein the printed circuit board has a top side, wherein an electrically conductive conducting element is arranged on and / or in the top side. This conducting element is protected from mechanical influences during the partial overmolding of the printed circuit board by a sealing element arranged in a frame. The invention also relates to a method for producing the electronic component. A further subject of the invention is the use of the electronic component in an inverter or a transmission control unit. Furthermore, the invention relates to a motor vehicle with the electronic component according to the invention.

[0004] Overmolded electronic components are generally well-known. These electronic components typically feature a printed circuit board. The problem with these electronic components is that when a tool is moved onto the circuit board to partially overmold the board, the conductor tracks arranged on the circuit board can be damaged in the sealing area. This leads to increased scrap and thus increased production costs.

[0005] It is an object of the invention to provide a partially overmolded electronic component with conductive elements in the edge region of an overmold, which can be produced easily and inexpensively.

[0006] This problem is solved by the subject matter of the independent patent claims. Preferred developments of the invention are the subject matter of the dependent patent claims, the following description, and / or the drawings. Each disclosed feature can represent an aspect of the invention, both individually and in combination, unless explicitly stated otherwise in the description.

[0007] In a first aspect, the invention relates to an electronic component for a motor vehicle, comprising a printed circuit board with an upper side, wherein an electrically conductive conducting element is arranged on and / or in the upper side, a frame element is placed on the upper side, which frame element is designed to be recessed in the region of the conducting element and seals against the conducting element via a sealing element, the sealing element has a lower rigidity than the frame element, and the upper side and the frame element are cast and / or overmolded in sections with an overmold material.

[0008] In other words, according to the first aspect of the invention, an electronic component is provided for a motor vehicle. The electronic component is preferably arranged in a transmission control unit or in an inverter of a motor vehicle. According to the invention, the electronic component has a printed circuit board. It is conceivable that the printed circuit board is preferably designed as a multilayer printed circuit board. The printed circuit board has an upper side, wherein an electrically conductive guide element is arranged on and / or in the upper side. If the printed circuit board is preferably designed as a flat or planar printed circuit board, the upper side is formed parallel to the plane of the printed circuit board.

[0009] Regarding the arrangement of the guide element on and / or in the upper side, “on the upper side” means that the guide element protrudes or projects beyond the upper side, and “in the upper side” means that the guide element is flush with the upper side.

[0010] A frame element is placed on the top side, and the frame element is recessed in the area of ​​the conductive element. In other words, the frame element rests on the top side. The contact can in particular be direct. In the area of ​​the electrical conductive element, the frame element itself has no direct contact with the conductive element. The conductive element seals off the frame element indirectly via a sealing element. The sealing element has less rigidity than the frame element. In other words, the material rigidity of the frame element is higher than the rigidity of the sealing element. The top side of the circuit board and the frame element are partially cast and / or overmolded with an overmold material. The frame element thus acts as a barrier for the overmold material. The overmold material can be used to protect the top side in the overmolded area, preferably from aggressive media.

[0011] In addition, by overmolding the frame element in sections, the frame element can be simultaneously fixed to the circuit board. Because the rigidity of the sealing element is reduced compared to the frame element, damage to the conductive element during the overmolding process, in which the frame element is also pressed against the circuit board, can be prevented. This can reduce circuit board scrap during the production of the electronic component, which can have a positive effect on manufacturing costs.

[0012] The sealing element is preferably a seal made from a fluororubber (FKM) compound. In other words, the sealing element preferably comprises a fluoroelastomer. Sealing elements made from a fluoroelastomer exhibit increased heat resistance and increased resistance to a wide range of chemicals. Thus, a sealing element made from FKM is preferably suitable for use against harsh media, such as oils, and is particularly applicable in the automotive sector, where electronic components can also sometimes reach high temperatures. The sealing element preferably has, but is not limited to, a Shore hardness between 55 Shore A and 85 Shore A, preferably between 60 Shore A and 83 Shore A, and particularly preferably between 70 Shore A and 80 Shore A, including the limits.

[0013] The overmold material preferably comprises a plastic. The plastic is particularly preferably a thermosetting plastic. Most preferably, the plastic comprises an additive. The additive or the matrix can increase the material stiffness of the overmold material in the cured state. Furthermore, the additive can increase the tensile strength of the overmold material, which can be advantageous in the event of increased temperature fluctuations to prevent the overmolding or the overmold material from cracking. In other words, the media impermeability of the overmold material can be increased in this way in a simple and cost-effective manner. The additive can preferably comprise a glass fiber and / or a carbon fiber.

[0014] An advantageous development of the invention is that the conducting element is an electrically conductive conductor track or electrically conductive conductor foil. The conductor track or conductor foil can preferably be made of copper and / or comprise copper. A conductor track or conductor foil can achieve increased functional density for an electrical control of the transmission control unit or an inverter. This increased functional density can have a beneficial effect on the cost of the electronic component and also on the installation space.

[0015] It is conceivable that the conductor track is designed to be coating-free, at least in sections. In other words, no solder resist is arranged and / or formed on the conductor track or the conductor foil, particularly in the overmolded area. Such conductor tracks therefore require special protection during a partial overmolding process in which an edge region of the overmolding falls within the area of ​​the conductor track or conductor foil, so that the conductor track or conductor foil is not damaged during the overmolding process, in which a sealing tool is placed against the top side of the circuit board.

[0016] In a preferred embodiment of the invention, the conductive element is an electrical component. The electrical component can preferably be a transistor, in particular a metal oxide semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT), or a connector. Consequently, the frame element does not rest directly on the electrical component, but rather seals against the electrical component via the sealing element. Thus, the electrical component can be protected from damage during partial overmolding, in which the electrical component also falls into the edge region of the overmolding.

[0017] According to a preferred embodiment of the invention, the frame element is at least partially integrally connected to the upper side. It is conceivable that the frame element has an adhesive layer on a side facing the upper side, which is preferably activated during the overmolding process and particularly preferably by heat input, thus forming a materially bonded connection with the upper side. In this way, the tightness between the frame element and the upper side of the circuit board can be increased, which can have a beneficial effect on the media tightness of the overmolded area of ​​the circuit board.

[0018] In principle, the frame element can be made of a metallic material. A preferred embodiment of the invention is that the frame element is made of a plastic and / or at least partially comprises plastic. The plastic is preferably a thermoplastic. The thermoplastic can be, but is not limited to, a polyamide. A frame element that is made of a plastic and / or comprises a plastic can be manufactured inexpensively and easily. Furthermore, with a frame element made of a plastic, in particular of a thermoplastic, a material-to-material connection to the top side of the circuit board can be achieved by applying heat to the frame element during the overmolding process, so that the adhesive layer can be dispensed with.In this way, increased media tightness between the top side and the frame element can be achieved in a simple and inexpensive way.

[0019] In an advantageous embodiment of the invention, a sealing element receptacle is formed in the frame element. The sealing element receptacle is configured and / or designed to receive and hold the sealing element, so that when the frame element is pressed onto the top side of the circuit board, the sealing element seals against the circuit element. In this way, the frame element, along with the sealing element arranged in the sealing element receptacle, can be easily placed onto the top side of the circuit board, thereby reducing the manufacturing costs of the electronic component.

[0020] In this context, a preferred development of the invention is that the sealing element can be and / or is inserted into the sealing element receptacle starting from an outer side of the frame element facing away from the upper side. In other words, it is provided that the sealing element receptacle is an opening and / or recess that runs through the frame element and is preferably closed at the edge. The opening and / or recess preferably has a configuration that tapers and / or narrows at least in sections starting from the outer side of the frame element towards the upper side of the circuit board. The sealing element can preferably be inserted into the sealing element receptacle in a simple manner starting from the outer side of the frame element. During the overmolding process, a stamp can act on the sealing element arranged in the sealing element receptacle and press it against the electrically conductive guide element.In this way, a safe and gentle sealing of the sealing element to the guide element can be achieved during the overmolding process.

[0021] A preferred embodiment of the invention is that the sealing element is at least partially cast with the overmold material. In particular, it is provided that the sealing element is at least partially cast with the overmold material in the sealing element receptacle. Particularly preferably, the sealing element is at least partially cast with the overmold material, starting from the outer side of the frame element, in the sealing element receptacle of the frame element. By casting the sealing element in sections, in particular within the sealing element receptacle, the sealing element can be securely and captively fixed in the sealing element receptacle. This can increase the media tightness in the sealing area between the electrical conducting element and the sealing element.

[0022] In an advantageous embodiment of the invention, a recess is formed in a wall of the sealing element receptacle, the wall facing a section and / or region of the circuit board encapsulated with the overmold material. During the overmolding process, the overmold material can flow onto the sealing element via the recess and enclose it at least partially in the sealing element receptacle, so that the sealing element is securely and captively arranged and fixed in the sealing element receptacle of the frame element.

[0023] In a second aspect, the invention relates to a method for producing the electronic component according to the invention, comprising the steps:

[0024] - Providing a printed circuit board having a top side, wherein an electrically conductive element is arranged on and / or in the top side,

[0025] - Arranging a frame element on the upper side, which is designed to be recessed in the region of the guide element, wherein a sealing element is arranged in the region of the guide element in the frame element, wherein the sealing element has a lower rigidity than the frame element,

[0026] - Pressing the frame element against and / or onto the top of the circuit board and the sealing element against and / or onto the conducting element,

[0027] - Overmolding and / or potting the upper side at least in sections with an overmold material.

[0028] In other words, according to the second aspect of the invention, a method for producing the electronic component according to the invention is specified, in which the frame element is placed on the top side of the circuit board. The sealing element is arranged in the frame element. The sealing element has reduced rigidity compared to the frame element. For the partial overmolding of the top side with an overmold material of the circuit board, the frame element is pressed against the top side, and the sealing element seals against the electrically conductive conducting element of the circuit board. The frame element thus acts as a boundary for overmolding the top side of the circuit board with the overmold material. The sealing element in the frame element can be used to simply and inexpensively prevent the conducting element from being damaged in the sealing area.

[0029] In a preferred embodiment of the invention, the step of pressing the frame element against and / or onto the upper side and the step of partially overmolding the upper side of the circuit board with an overmold material take place simultaneously. Simultaneously means that while the frame element is being pressed onto the upper side, the upper side is partially overmolded. The pressing process can preferably last somewhat longer than the overmolding process. It is therefore conceivable that a pressing force is applied to the frame element in order to press it onto the upper side. The overmolding process then begins. The overmolding process ends, with the pressing force on the frame element being reduced or removed after or at the end of the overmolding process. By pressing the frame element onto the upper side beforehand, it is possible to prevent the overmold material from escaping between the frame element and the upper side when the overmolding process starts.If the contact pressure is released or removed after the end of the overmolding process, it can be ensured that the overmold material hardens before the contact pressure on the frame element and thus on the top side of the circuit board is reduced. However, it is also conceivable and not impossible that the overmolding process begins immediately after the pressing process and ends together with the pressing process. In this case, the pressing process and the overmolding process are not only simultaneous, but also concurrent, since they have the same processing time. This can reduce the cycle time for manufacturing the electronic component, which can have a positive effect on manufacturing costs.

[0030] An advantageous development of the invention lies in the fact that, during the step of overmolding the top side of the circuit board, a temperature of greater than 80°C, in particular greater than 100°C, acts on the top side of the circuit board and / or the frame element, thereby achieving a material-to-material connection between the frame element and the top side. The temperature is preferably not greater than 150°C and particularly preferably not greater than 130°C. The material-to-material connection can preferably be achieved via a thermally activatable adhesive layer between the frame element and the top side of the circuit board. It is also conceivable for the frame element to be made of a plastic, wherein the frame element softens in sections due to the heat input and thus forms a material bond with the top side of the circuit board. The material-to-material connection can increase the media-tightness between the circuit board and the frame element.

[0031] In a preferred development of the invention, during the step of partially overmolding the top side of the circuit board, the sealing element is also at least partially encapsulated in a sealing element receptacle formed in the frame element. In particular, the sealing element is encapsulated within the sealing element receptacle on a side facing away from the top side. By encapsulating the sealing element within the sealing element receptacle, it can be securely fixed and captively arranged in the sealing element receptacle, so that the media impermeability to the guide element achieved via the sealing element can be permanently ensured.

[0032] In a third aspect, the invention relates to the use of the electronic component according to the invention in a transmission control unit or in an inverter for a motor vehicle.

[0033] In other words, the electronic component is installed in a transmission control unit of a motor vehicle. The transmission control unit is preferably surrounded at least in sections by oil, in particular a transmission oil. The oil can preferably act against the overmolding. It is also conceivable for the electronic component to be arranged in an inverter of a traction drive of a motor vehicle. The inverter can preferably be cooled. The inverter can be cooled by oil cooling or water-glycol cooling, which preferably acts against the overmolding of the electronic component.

[0034] In a fourth aspect, the invention relates to a motor vehicle with the electronic component according to the invention. It should be noted that all features described above and below with respect to one aspect of the present invention equally apply to any other aspect of the present invention. In particular, all features of the electronic component can equally apply to the method for producing the electronic component, to the use of the electronic component in a transmission control unit or an inverter, and / or to the motor vehicle. This also applies vice versa.

[0035] Further features and advantages of the present invention emerge from the dependent claims and the following exemplary embodiments. The exemplary embodiments are not restrictive, but rather to be understood as examples. They are intended to enable the skilled person to implement the invention. The applicant reserves the right to make individual and / or several of the features disclosed in the exemplary embodiments the subject of patent claims or to incorporate such features into existing patent claims. The exemplary embodiments are explained in more detail with reference to drawings.

[0036] In these show:

[0037] Fig. 1 shows a section of an electronic component with a circuit board and frame element,

[0038] Fig. 2 a section of the electronic module with the circuit board, the frame element and an inserted sealing element,

[0039] Fig. 3 a section of the electronic module with the circuit board, the frame element and a partial encapsulation of the circuit board,

[0040] Fig. 4 a section through the electronic module in the area of ​​an electrically conductive element of the circuit board,

[0041] Fig. 5 shows a method for manufacturing the electronic module,

[0042] Fig. 6 a motor vehicle with the electronic module.

[0043] In Fig. 1, Fig. 2 and Fig. 3 a section of an electronic component EB is shown.

[0044] 1 to 3 simultaneously. The electronic component EB has a printed circuit board LP. The printed circuit board LP can preferably be designed as a multi-layer printed circuit board. The printed circuit board LP has an upper side OS, wherein an electrically conductive conducting element LE is arranged on and / or in the upper side OS. If the printed circuit board LP is designed as a flat or planar printed circuit board LP, the upper side OS is formed parallel to the plane of the printed circuit board LP. Arranged on the upper side OS means that the conducting element LE protrudes from the upper side OS. In the upper side OS means that the conducting element LE is flush with the upper side OS. In the present exemplary embodiment, the conducting element LE is an electrically conductive conductor track. The conductor track can preferably be made of copper and / or comprise copper. With a conductor track, an increased functional density for an electrical control system can be realized.The increased functional density can have a beneficial effect not only on the cost of the electronic component EB, but also on the installation space of the electronic component EB.

[0045] A frame element RE is mounted on the upper side OS. The frame element RE is recessed in the area of ​​the conducting element LE. In other words, the frame element RE rests on the upper side OS. In the present embodiment, it rests directly on the upper side OS. In the area of ​​the electrically conductive conducting element LE, the frame element RE itself has no direct contact with the conducting element LE.

[0046] Furthermore, it is provided that a sealing element receptacle DEA is formed in the frame element RE. The sealing element receptacle DEA is configured and / or designed to receive and hold a sealing element DE, as shown in Fig. 2, so that the sealing element DE seals against the conductor element LE when the frame element RE is pressed onto the top side OS of the printed circuit board LP.

[0047] The sealing element receptacle DEA is an opening and / or recess extending through the frame element RE, preferably with a closed edge. Thus, the sealing element DE can be inserted into the sealing element receptacle DEA starting from an outer side AS of the frame element RE facing away from the upper side OS.

[0048] The opening and / or recess of the sealing element receptacle DEA has a tapered and / or tapered configuration, at least in sections, extending from the outer side AS of the frame element RE toward the upper side OS of the printed circuit board LP. The sealing element DE can preferably be inserted into the sealing element receptacle DEA in a simple manner, extending from the outer side AS of the frame element RE, and can seal against an inclined inner wall of the sealing element receptacle DEA, thereby increasing the media tightness of the sealing element DE to the frame element RE.

[0049] The guide element LE seals against the frame element RE indirectly via the sealing element DE. The sealing element DE has a lower rigidity than the frame element RE. In other words, the material rigidity of the frame element RE is higher than the rigidity of the sealing element DE.

[0050] The sealing element DE is preferably an elastomer and the frame element RE is particularly preferably made of a thermoplastic material.

[0051] The top side of the circuit board LP and the frame element RE are cast and / or overmolded in sections with an overmold material OMM, as can be seen in Fig. 3. The frame element RE thus acts as a barrier for the overmold material OMM. The overmold material OMM can preferably protect the top side OS and / or the electrical components (not shown) arranged on the top side OS in the overmolded area from aggressive media. In addition, by overmolding the frame element RE in sections, the frame element RE can be fixed to the circuit board LP at the same time. Due to the fact that the rigidity of the sealing element DE is reduced compared to the frame element RE, damage to the conductive element RE during the overmold process, in which the frame element RE is also pressed against the circuit board LP, can be avoided.This can reduce waste during the production of printed circuit boards (LP), which can have a positive effect on the manufacturing costs of the electronic component (EB).

[0052] It can also be seen that a recess VT is formed in a wall of the sealing element receptacle DEA, the wall facing a section and / or region of the printed circuit board LP cast with the overmold material OMM, which recess is also cast with the overmold material OMM. During the overmolding process, the overmold material OMM can flow via the recess onto the sealing element DE and enclose it at least in sections in the sealing element receptacle DEA, so that the sealing element DE is arranged and fixed in a secure and captive manner in the sealing element receptacle DEA of the frame element RE. Fig. 4 shows a section AA through the electronic component EB shown in Fig. 3. It can be seen that the frame element RE rests on the upper side OS of the printed circuit board LP and has no direct contact with the conducting element LE. The sealing element DE arranged in the frame element RE seals against the conducting element LE.The sealing element DE is cast with the overmold material OMM in the sealing element holder DEA, at least in sections, and is thus securely fixed in the sealing element holder DEA.

[0053] Fig. 5 shows a method for manufacturing the electronic component EB.

[0054] In a first step 100, the printed circuit board LP is provided. The printed circuit board LP has the top side OS, with the electrically conductive guide element LE arranged on and / or in the top side OS.

[0055] In a second step 110, a frame element RE is arranged on the upper side OS of the printed circuit board LP, wherein the frame element RE has a sealing element DE in the region of the conducting element LE, and the sealing element DE has a lower rigidity than the frame element RE.

[0056] In a third step 120, the frame element RE is pressed against the top side OS of the printed circuit board LP, and the sealing element acts and seals against the conductive element.

[0057] In a fourth step 130, the upper side OS of the printed circuit board LP is overmolded at least in sections or partially with an overmold material OMM.

[0058] The frame element RE acts as a boundary for overmolding the top surface OS of the printed circuit board LP with the overmold material OMM. The sealing element DE in the frame element RE provides a simple and cost-effective way to prevent damage to the conductive element LE in the sealing area, as the mechanical impact on the conductive element LE in the sealing area during the pressing process of the frame element RE onto the top surface OS of the printed circuit board LP can be significantly reduced.

[0059] Fig. 6 shows a motor vehicle (KFZ) with the electronic component (EB). The electronic component (EB) is preferably integrated into a transmission control unit (GSG).

Claims

Patent claims 1 . Electronic component (EB) for a motor vehicle (KFZ), comprising a printed circuit board (LP) with an upper side (OS), wherein an electrically conductive conducting element (LE) is arranged on and / or in the upper side (OS), a frame element (RE) is placed on the upper side (OS), which frame element is designed to be recessed in the region of the conducting element (LE) and seals against the conducting element (LE) via a sealing element (DE), wherein the sealing element (DE) has a lower rigidity than the frame element (RE), and the upper side (OS) and the frame element (RE) are cast and / or overmolded in sections with an overmold material (OMM).

2. Electronic component according to claim 1, characterized in that the conducting element (LE) is an electrically conductive conductor track or electrically conductive conductor foil.

3. Electronic component according to one of the preceding claims, characterized in that the conducting element (LE) is an electrical component.

4. Electronic component according to one of the preceding claims, characterized in that the frame element (RE) is at least partially connected to the upper side (OS) in a materially bonded manner.

5. Electronic component according to one of the preceding claims, characterized in that the frame element (RE) is formed from a plastic and / or at least partially comprises plastic.

6. Electronic component according to one of the preceding claims, characterized in that a sealing element receptacle (DEA) is formed in the frame element (RE).

7. Electronic component according to claim 6, characterized in that the sealing element (DE) can be inserted and / or is inserted into the sealing element receptacle (DEA) starting from an outer side (AS) of the frame element (RE) facing away from the upper side (OS).

8. Electronic component according to one of the preceding claims, characterized in that the sealing element (DE) is at least partially encapsulated with the overmold material (OMM).

9. Electronic component according to one of the preceding claims, characterized in that in a wall of the sealing element receptacle (DEA), wherein the wall faces a section of the printed circuit board (LP) encapsulated with the overmold material (OMM), a recess (VT) is formed, which is also encapsulated with the overmold material (OMM).

10. A method for producing an electronic component (EB) according to one of the preceding claims, comprising the steps: - Providing a printed circuit board (LP) having a top side (OS), wherein an electrically conductive element (LE) is arranged on and / or in the top side (OS), - Arranging a frame element (RE) on the upper side (OS), which is designed to be recessed in the region of the guide element (LE), wherein a sealing element (DE) is arranged in the frame element (RE) in the region of the guide element (LE), wherein the sealing element (DE) has a lower rigidity than the frame element (RE), - Pressing the frame element (RE) against and / or onto the top side (OS) of the printed circuit board (LP) and the sealing element (DE) against and / or onto the guide element (LE), - Overmolding and / or potting the upper side (OS) at least in sections with an overmold material (OMM).

11. Method according to claim 10, characterized in that the step of pressing the frame element (RE) onto the upper side (OS) and the step of partially overmolding the upper side (OS) of the printed circuit board (LP) with the overmold material (OMM) take place simultaneously.

12. The method according to claim 10 or 11, characterized in that during the step of overmolding the upper side (OS), a temperature of greater than 80°, in particular greater than 100°C, acts on the upper side (OS) and / or the frame element (RE) and thereby a material connection between the frame element (RE) and the upper side (OS) is achieved.

13. Method according to one of claims 10 to 12, characterized in that in the step of overmolding the upper side (OS), the sealing element (DE) is cast at least in sections in a sealing element receptacle (DEA) formed in the frame element (RE).

14. Use of an electronic component (EB) according to one of claims 1 to 10 in a transmission control unit (GSG) or in an inverter for a motor vehicle (KFZ).

15. Motor vehicle (KFZ) with an electronic component (EB) according to one of the Claims 1 to 10.

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