Frame for connection to at least one printed circuit board and a housing of an electronic module, system comprising at least one printed circuit board and frame, and electrical module

Abstract

A frame for connecting to at least one printed circuit board is proposed, wherein the frame comprises: outer struts forming the frame, screwing points distributed over the outer struts on a frame side to be connected to a printed circuit board, as well as positioning domes arranged on the same side, distributed over the outer struts and formed as fixing points, and at least one housing screwing point formed as a through-opening, which is arranged in a central region of the frame. Furthermore, a system comprising a first and / or a second printed circuit board and a frame is provided.

Description

[0001] The present invention relates to the field of electromobility, in particular to electronic modules for an electric drive.

[0002] The use of electronic modules, such as power electronics modules, in motor vehicles has increased significantly in recent decades. This is due, on the one hand, to the need to improve fuel economy and vehicle performance, and, on the other hand, to advances in semiconductor technology. The main component of such an electronic module is power electronics, which includes a DC / AC inverter used to supply electrical machines such as electric motors or generators with multi-phase alternating current (AC). The electronic module has a housing in which all of the electronic module's components are arranged to convert direct current generated by a DC energy source, such as a battery, into multi-phase alternating current. A printed circuit board is usually provided to control the power electronics and is connected to the power electronics.The circuit board is equipped with a wide variety of electronic components such as coils, capacitors, and microcontrollers and is designed to carry a low-voltage potential (e.g., 40V) and a high-voltage potential (e.g., 400V). The circuit board is typically positioned over the entire surface of the components located in the housing, such as the power electronics, a heat sink, etc., and is mechanically connected to the housing and components within the housing, such as the heat sink.

[0003] The problem here can be that, due to the component load and the available installation space, the circuit board can only be mechanically secured at the outer edges, while the central area cannot be mechanically secured to the underlying components, or can only be secured at a few points. As a result, the stability and vibration resistance of the circuit board are not optimal.

[0004] In current power electronics applications, it is possible that two circuit boards are arranged parallel to one another and connected mechanically via screw domes / spacers, as well as electrically and / or signal-wise using cables, for example. When two circuit boards are connected parallel to one another, several problems can arise. The two circuit boards are mounted and connected, for example, using individual spacer domes made of metal (for screwing, e.g. with screws with a metric thread) or plastic (for snapping into the circuit board) arranged on the circuit board(s). The fastening points and blocking areas on the circuit boards must always be directly above one another. Flexible positioning, which is necessary due to circuit board layout and component position, is therefore limited. In addition, installation space in height is required, which may not be available in some circumstances.Furthermore, the positioning of the circuit boards relative to each other for assembly is not (sufficiently) available. This makes blind assembly of the connector system located on the underside of the second circuit board for connecting to the first circuit board difficult.

[0005] The invention is therefore based on the object of providing an improved possibility for stabilizing a single circuit board, as well as a stabilization and improved connection of several circuit boards.

[0006] This problem is solved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0007] A frame for connection to at least one printed circuit board is proposed, wherein the frame has: outer struts forming the frame, screwing points distributed over the outer struts on a frame side to be connected to a printed circuit board, as well as positioning domes arranged on the same side, distributed over the outer struts and formed as fixing points, at least one housing screwing point formed as a through-opening, which is arranged in a central region of the frame.

[0008] In one embodiment, opposing outer struts are mechanically connected to one another by means of one or more ribs.

[0009] In one embodiment, screwing points are arranged on opposite sides of the frame at different positions in such a way that they are not arranged one above the other.

[0010] In one embodiment, an auxiliary element for cable routing and / or cable fixation is attached to at least one outer edge region of the frame and is preferably formed integrally with the frame. In one embodiment, the frame is made of a non-electrically conductive or weakly conductive material.

[0011] Furthermore, a system comprising a first printed circuit board and a frame is proposed, wherein a surface of the first printed circuit board has screw holes and openings, and wherein the screwing points and the positioning domes of a first frame side of the frame are arranged such that they correspond to the screw holes and openings of the first printed circuit board, and wherein the first printed circuit board is connected to the first frame side of the frame via the screwing points.

[0012] In one embodiment, the system further comprises a second circuit board having screw holes and openings on one surface, and wherein the frame has screw points and positioning domes on a second frame side opposite the first frame side, which correspond to the screw holes and openings of the second circuit board, and wherein the second circuit board is connected to the second frame side of the frame via the screw points.

[0013] In one embodiment, the second circuit board has a smaller circumference than the first circuit board, and wherein the circumference of the frame corresponds at least to the circumference of the second circuit board.

[0014] In one embodiment, the two circuit boards are electrically and / or signal-wise connected to one another by means of at least one connector system arranged on the mutually facing surfaces of each circuit board.

[0015] In one embodiment, an adhesive is provided on a part of the frame, in particular an outer side of a base of a screwing point, or an area of ​​the circuit board opposite the base in such a way that it fastens the frame and the circuit board to one another at this area.

[0016] Furthermore, an electronic module is proposed, comprising a housing with components arranged therein for controlling an electric drive of a motor vehicle, comprising power electronics and at least one heat sink, and the system comprising at least the circuit board and the frame, wherein a fastening means is guided through each of the screwing points of the frame and is engaged with the associated screw holes in the circuit board, and wherein a fastening means is engaged with a screw dome of the housing located below the circuit board through each housing screwing point, so that at least the first circuit board and the frame are fastened to the housing.

[0017] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, with reference to the figures of the drawing, which illustrate details of the invention, and from the claims. The individual features can be implemented individually or in combination in a variant of the invention.

[0018] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Fig. 1 shows a single circuit board with frame according to an embodiment of the present invention. Fig. 2 shows a first frame side (mounting side of the first circuit board) of the frame according to an embodiment of the present invention. Fig. 3 shows the first circuit board with attachment points and positioning points according to an embodiment of the present invention. Fig. 4 shows a connection of two circuit boards by means of a frame according to an embodiment of the present invention. Fig. 5 shows a second frame side (mounting side of the second circuit board) opposite the first frame side according to an embodiment of the present invention. Fig. 6 to 8 show enlarged views A, B, C of Fig. 5 marked areas of the frame. Fig. 9 shows a schematic sectional view through a screwing point of the first circuit board to the housing according to an embodiment of the present invention. Fig. 10 shows a schematic sectional view through a screwing point of the second circuit board to the housing according to an embodiment of the present invention.

[0019] In the following descriptions of the figures, the same elements or functions are provided with the same reference symbols.

[0020] The present invention relates to printed circuit boards 1, 2 which are used in the field of electromobility, wherein both a single printed circuit board 1 and two parallel printed circuit boards 1, 2 can be present. In particular, the described printed circuit boards 1, 2 are arranged in a (only in Fig. 9 and Fig. 10) housing of an electronic module is used to control, among other things, the power electronics present there (in particular an inverter). For this purpose, the printed circuit boards 1, 2 are accordingly equipped with electronic components such as coils, capacitors, microcontrollers, etc. In the case of two printed circuit boards 1, 2 arranged parallel to one another, the outer circumference of one of the printed circuit boards (hereinafter printed circuit board 2) is smaller than that of the other printed circuit board (hereinafter printed circuit board 1), wherein the printed circuit board with the smaller circumference (printed circuit board 2) is arranged above the other printed circuit board (printed circuit board 1), which is attached to and / or in the housing. The housing is usually in contact with a heat sink in order to be able to provide cooling for the power electronics.Since the assembly of the circuit boards 1, 2 is predetermined and cannot be easily changed, the screw holes must be positioned in free places that are as easily accessible as possible for assembly (inserting a screw through the screw hole into the screw dome of the housing).

[0021] As already mentioned at the beginning, it is often only possible to fasten the printed circuit boards 1, 2 at their outer edge area. This means that the printed circuit board 1, 2 is not optimally vibration-proof and stabilized, especially in its central area. For this reason, a frame 100 is provided which has screwing points 102a, 102b and housing screwing points 102c, 102d, as well as positioning domes 103, and thus assumes the fastening and positioning function. The screwing points 102a, 102b are preferably not formed as a continuous opening through the frame 100, but have a base, i.e. are only open on one side. This means that, for example, chips generated by screwing the printed circuit board 1, 2 and frame 100 together using appropriate fastening means such as screws remain in the screwing point 102a, 102b. The housing screwing points 102c and 102d are formed as a continuous opening through the frame 100 and serve to attach a fastening means, e.g.in the form of a screw 23, 24, which reaches up to a screw dome 3 located in the housing and is fastened there, as in . Fig. 9 and Fig. 10 shown.

[0022] A second aspect addresses the problem that, when using two printed circuit boards 1, 2, the positioning and fastening of the two printed circuit boards 1, 2 parallel to each other, as well as the connector contact for the electrical and / or signal connection of the printed circuit boards 1, 2 to each other, is partially limited and / or very difficult using the current screw connections. To solve this problem, the frame 100 is extended by having screw points 102a, 102b and positioning domes 103 on both sides, thus assuming a fastening and positioning function on both sides. In the case that the frame 100 has screwing points 102a, 102b and positioning domes 103 on both sides, the screwing points 102a, 102b and positioning domes 103 on one side of the frame 100 are arranged at different positions than the screwing points 102a, 102b and positioning domes 103 on the other side of the frame 100.

[0023] The proposed frame 100 is advantageously formed in one piece by external struts 101, as shown for example in Fig. 1, Fig. 2 and Fig. 5. The frame 100 is connected with a first frame side (mounting side) thereof to a first printed circuit board 1, as shown in Fig. 1. In the area of ​​this first frame side, screwing points 102a are arranged in the form of openings distributed over the outer struts 101, as in Fig. 2. The printed circuit board 1 also has corresponding openings on the side facing the frame 100, so that the printed circuit board 1 and frame 100 can be fastened to each other, e.g., by means of a screw. Furthermore, on the same frame side, positioning domes 103 are arranged, distributed over the outer struts 101 and formed as fixing pins, as also shown in Fig. 1 and Fig. 2. These serve to position the printed circuit board 1 (with corresponding openings 11 for receiving the positioning domes 103) and frame 100 together.

[0024] In one embodiment, the frame 100 has one or more ribs 104 which form a connection between opposing outer struts 101 and thus act as frame reinforcement, as in Fig. 1, Fig. 2 and Fig. 5. The ribs 104 also have screwing points 102a (102b on the second frame side) and optional positioning domes 103 and are arranged such that components located on the circuit board 1, 2 (coils, capacitors, etc.) remain free, i.e., are located within the spaces between outer struts 101 and ribs 104.

[0025] The screw points 102a, 102b for the printed circuit boards 1, 2 on the frame 100 are incorporated into the outer struts 101 on one or both sides of the frame. They have a suitable shape for receiving a predetermined screw 10, 20, which is generally a self-tapping screw, as known from the prior art. The screw points 102a, 102b and positioning domes 103 are present on both sides of the frame 100 if two printed circuit boards 1, 2 are provided. The positioning domes 103 are formed as elevations on the outer struts 101, in particular in the form of pins, i.e., needle-like protrusions. They serve to insert into corresponding openings 11, 21 of the printed circuit boards 1 and 2 to be connected to the frame during assembly of the frame 100, and thus to position the frame 100 and the printed circuit boards 1 and 2 against one another.

[0026] In Fig. 1, only a first circuit board 1 is connected to the frame 100. In this case, the frame 100 serves to stabilize the circuit board 1 and to protect the components on the circuit board 1 from vibrations. Fig. 2 shows the first frame side (mounting side) of the frame 100, which rests on the first circuit board 1 after mounting. In Fig. Figure 3 shows the first printed circuit board 1 with exemplary screw holes (with screw 10 already screwed in) and openings 11 distributed on its upper side (mounting side) for receiving a positioning dome 103. The screw holes and openings 11 correspond to those of the frame 100 when the printed circuit board 1 and frame 100 are attached to each other. The same applies to a second printed circuit board 2 to be attached to an opposite side of the frame 100.

[0027] In the described embodiment, the frame 100 can be dimensioned such that its contour corresponds to the contour of the first printed circuit board 1. It can be the same size as the printed circuit board 1 or smaller. It is advantageously dimensioned such that it extends at least to the center of the printed circuit board 1 in order to be able to exert its stabilizing and vibration-protecting (inhibiting) effect.

[0028] In Fig. 4 shows a further embodiment of the invention, in which a second circuit board 2 is provided in addition to the first circuit board 1. The second circuit board 2 is arranged parallel to the first circuit board 1 and is also positioned and fastened on the frame 100. For this purpose, the second frame side of the frame 100 opposite the first frame side also has screwing points 102b and positioning domes 103, as shown in Fig. 5. These are formed like the screwing points 102a and positioning domes 103 described for the first embodiment, i.e. as a receptacle for a given screw or as a raised portion. As shown in Fig. 2, the screwing points 102a, 102b for the two circuit boards 1, 2 are arranged directly next to each other, i.e. at different positions of the frame.

[0029] Fig. 6 to 8 each show an enlarged area A ( Fig. 6), B ( Fig. 7) and C ( Fig. 8) from Fig. 5. During assembly, the second circuit board 2 is applied to the frame 100, which is already positioned and secured on the first circuit board 1. The positioning domes 103 serve to ensure correct positioning. The second circuit board 2 is attached to the frame 100 via the screw points 102a, 102b.

[0030] Both circuit boards 1, 2 must be electrically and / or signal-wise connected to each other. This is achieved via a connector system (not described in detail here) arranged on the mutually facing surfaces of the circuit boards 1, 2. For this purpose, the frame 100 has positioning domes 103 on both sides for securing the circuit boards 1, 2. These domes are arranged such that, during assembly of the second circuit board 2, the circuit boards 1, 2 are positioned relative to each other in such a way that the electronic connector system on both circuit boards 1, 2 is located blindly. This enables secure blind assembly.

[0031] In the embodiments shown, the frame 100 is dimensioned such that its outer contour (its circumference) essentially corresponds to the outer contour (the circumference) of the second circuit board 2, so that the latter can be fastened to the frame 100 at its edge regions. Thus, the second circuit board 2 is stabilized by the frame in all areas. The frame 100 could also be smaller than the second circuit board 2; however, additional fastening elements for stabilization would then have to be provided between the first and second circuit boards 1, 2, which would increase the assembly effort. In this respect, the frame 100 advantageously has at least the size (external dimensions) of the second circuit board 2, but can also be larger if this is advantageous for stabilizing the first circuit board 1.

[0032] In each design, the screw points 102 and the positioning domes 103 allow a certain amount of play so that tolerances due to the manufacturing of the frame 100 and printed circuit boards 1, 2 can be compensated. However, the tolerances are not so large that they have a negative impact on the electrical and / or signaling connection.

[0033] In all embodiments, an unfavorable, predetermined positioning of the components on the printed circuit board(s) 1, 2 may result in the frame 100 being weakened in its cross-section and thus becoming more susceptible to vibrations. Therefore, at least one housing screwing point 102c, 102d is advantageously provided in a central region of the frame 100 in order to secure at least the printed circuit board 1 and the frame 100 to the housing of the electronic module, more precisely to the corresponding screw bosses 3 thereof, as shown in, for example, Fig. 1 and Fig. 2. The at least one housing screwing point 102c, 102d is connected, for example, via a web 104a to ribs 104 and / or outer struts 101, or is integrated into a rib 104.

[0034] In one embodiment, at least one housing screwing point 102c is provided, which is formed as a continuous opening in the frame 100, so that the frame 100 and the printed circuit board 1 can be fastened to a screw boss 3 of the housing by means of, for example, a screw 23, by engaging the screw 23 and the screw boss 3 with each other, as shown in Fig. 1 and Fig. 9. Advantageously, a screwing point 102b is provided directly next to the housing screwing point 102c in order to connect a second printed circuit board 2 to the frame.

[0035] In an embodiment in which a second printed circuit board 2 is positioned above the printed circuit board 1, at least one further housing screwing point 102d is provided, which is formed as a through-opening in the frame 100, but is arranged remotely from the housing screwing point 102c. This serves to fasten the printed circuit board 2 via the frame 100 and a through-opening in the printed circuit board 1 by means of, for example, a screw 24 to a screw boss 3 of the housing, as shown in Fig. 1, Fig. 4 and Fig. 10. The frame 100 and the underlying circuit board 1 are clamped between the circuit board 2 and the housing.

[0036] In an embodiment in which a second circuit board 2 is positioned above the circuit board 1, in an alternative embodiment at least one housing screwing point is provided, which is formed as a continuous opening in the frame 100 and serves to fasten both circuit boards 1, 2 via the frame 100 by means of a screw to a screw dome 3 of the housing.

[0037] The additional housing screwing points 102c and 102d provided centrally in the frame 100 create a stable connection between all components of the printed circuit board assembly, i.e. the printed circuit board(s) 1, 2 and the frame 100, without impairing the assembly of the other components on the printed circuit board(s) 1, 2.

[0038] In all versions, due to the thickness of the frame 100, the screwing points 102a, 102b are sleeve-shaped to accommodate the screws. The housing screwing points 102c, 102d are also sleeve-shaped.

[0039] The number and position of the screw points 102a, 102b and the housing screw points 102c, 102d are selected by the person skilled in the art according to the application and the available space on the printed circuit board 1, 2 to ensure the desired stability and vibration resistance of the printed circuit boards 1, 2. Likewise, the number and position of the positioning domes 103 are selected by the person skilled in the art according to the application to achieve the desired positioning accuracy.

[0040] In the case of two printed circuit boards 1, 2, the arrangement of the screwing points 102a, 102b arranged on different frame sides corresponds to the screw holes on the top side (mounting side) of the printed circuit boards 1, 2 (each shown with screws 20 already screwed in), which are arranged at positions where there are no components on the printed circuit board 1, 2. Screwing points 102a, 102b of both printed circuit boards 1, 2 can be arranged in pairs next to each other, i.e., with a small distance from each other, as in Fig. 6, which shows an enlargement of area A from Fig. 5. They can also be arranged at a distance from each other, as in Fig. 7 and Fig. 8, which shows an enlargement of areas B and C from Fig. 5. Due to the independent positioning of the screwing points 102a, 102b of the two circuit boards 1, 2, the requirements of the individual circuit boards 1, 2 regarding routing and component placement can be taken into account independently of one another.

[0041] The arrangement of the screwing points 102a, 102b and positioning domes 103 to each other can also be freely selected, whereby a certain proximity to each other increases the accuracy of the screwing.

[0042] Due to the differently arranged screw dome positions for circuit boards 1, 2, the circuit boards 1, 2 can be positioned closer together, since a full dome height of the screw points 102a, 102b is available for one screw length. If both circuit boards 1, 2 were screwed into a single screw point, the minimum distance between the circuit boards 1, 2 would be almost twice as large.

[0043] The frame 100 also serves as a spacer for the two circuit boards 1, 2. The frame 100 is advantageously made of a plastic that is electrically non-conductive or only very weakly conductive, and is particularly reinforced with fiberglass. The frame 100 is advantageously manufactured using an injection molding process.

[0044] In one embodiment, at least a portion of the frame 100 is attached to the circuit board 1 and / or 2 using an adhesive. The adhesive is advantageously provided on the back of one of the screw points 102a, 102b. This additional, flat attachment improves vibration resistance.

[0045] In a further embodiment, one or more auxiliary elements 105 for cable routing and / or cable fixing (electrical or signal-carrying) are provided on the outer region of the frame 100, as in Fig. 1, Fig. 2, Fig. 4, Fig. 6 and Fig.7. These are advantageously also formed integrally with the frame 100 and have a suitable shape for engaging with the fixing elements provided on the cables in order to guide and fix the cables. The shape is usually a hole (round or slot-shaped) to accommodate a counterstructure or a cable tie, etc. Suitable shapes and fastening means are known from the prior art. The auxiliary elements 105 are advantageously arranged close to the screwing points 102a, 102b, since mechanical forces acting on the circuit board 1, 2 can occur due to the cables, which can be best absorbed close to the screwing points 102a, 102b.

[0046] An electronic module within the scope of this invention serves to operate an electric drive, in particular an axle electrically driven by the electric drive, of a motor vehicle powered by a rechargeable battery or fuel cell. The motor vehicle is in particular a commercial vehicle such as a truck or a bus, or a passenger car. The electronic module comprises a DC / AC inverter. It can also comprise or be a part of an AC / DC rectifier, a DC / DC converter, a transformer, and / or another electrical converter or a part of such a converter. In particular, the electronic module serves to supply current to an electric machine, for example an electric motor and / or a generator.A DC / AC inverter is preferably used to generate a multiphase alternating current from a direct current generated by a DC voltage from a power source, such as a battery. The electronic module has a housing in which the inverter and other components are arranged. The circuit board(s) 1, 2 are also arranged in the housing and are part of the electronic module, as already described in the introduction. List of reference symbols 100 frames 101 outer struts 102a, 102b Screwing points 102c, 102d Housing screwing points 103 positioning domes 104 ribs 104a footbridge 105 Cable fixation 1, 2 circuit board 10, 20, 23, 24 screws 11, 21 openings 3 screw dome housing

Claims

[1] Frame (100) for connection to at least one printed circuit board (1, 2), the frame (100) comprising: - outer struts (101) forming the frame (100), - on a frame side to be connected to a printed circuit board (1, 2), screwing points (102a, 102b) distributed over the outer struts (101), as well as positioning domes (103) arranged on the same side, distributed over the outer struts (101) and formed as fixing points, - at least one housing screwing point (102c, 102d) formed as a through-opening, which is arranged in a central region of the frame (100). [2] Frame (100) according to claim 1, wherein opposing outer struts (101) are mechanically connected to one another by means of one or more ribs (104). [3] Frame (100) according to claim 2, wherein screwing points (102a, 102b) are arranged on opposite sides of the frame at different positions such that they are not arranged one above the other. [4] Frame (100) according to one of the preceding claims, wherein an auxiliary element (105) for cable guidance and / or cable fixing is attached to at least one outer edge region of the frame (100) and is preferably formed integrally with the frame (100), and / or wherein the frame (100) consists of an electrically non-conductive or weakly conductive material. [5] System comprising a first printed circuit board (1) and a frame (100) according to one of the preceding claims, wherein a surface of the first printed circuit board (1) has screw holes and openings (11), and wherein the screwing points (102a) and the positioning domes (103) of a first frame side of the frame (100) are arranged such that they correspond to the screw holes and openings (11) of the first printed circuit board (1), and wherein the first printed circuit board (1) is connected to the first frame side of the frame (100) via the screwing points (102a). [6] System according to claim 5, further comprising a second circuit board (2) having screw holes and openings (21) on one surface, and wherein the frame (100) has, on a second frame side opposite the first frame side, screwing points (102b) and positioning domes (103) which correspond to the screw holes and openings (21) of the second circuit board (2), and wherein the second circuit board (2) is connected to the second frame side of the frame (100) via the screwing points (102b). [7] System according to claim 6, wherein the second circuit board (2) has a smaller circumference than the first circuit board (1), and wherein the circumference of the frame (100) corresponds at least to the circumference of the second circuit board (2). [8] System according to claim 6 or 7, wherein the two circuit boards (1, 2) are electrically and / or signal-technically connected to one another by means of at least one connector system arranged on the mutually facing surfaces of each circuit board (1, 2). [9] System according to one of claims 6 to 8, wherein an adhesive is provided on a part of the frame, in particular an outer side of a bottom of a screwing point (102a, 102b), or a region of the circuit board (1, 2) opposite the bottom, in such a way that it fastens the frame (100) and the circuit board (1, 2) to one another at this region. [10] Electronic module, comprising - a housing with components arranged therein for controlling an electric drive of a motor vehicle, comprising power electronics and at least one heat sink, and - the system comprising at least one printed circuit board (1, 2) and a frame (100) according to one of claims 5 to 9, wherein a fastening means is guided through each of the screwing points (102a, 102b) of the frame (100) and is brought into engagement with the associated screw holes in the printed circuit board (1, 2), and wherein a fastening means (23, 24) is brought into engagement with a screw dome (3) of the housing located below the printed circuit board (1) through each housing screwing point (102c, 102d), so that at least the first printed circuit board (1) and the frame (100) are fastened to the housing.

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