Electronic assembly for a motor vehicle

Abstract

The invention relates to an electronic assembly (10) for a motor vehicle (2), comprising a housing (12) in which a printed circuit board (18) is arranged. The printed circuit board has a flat first printed circuit board part (22) and a flat second printed circuit board part (24), which are electrically connected to each other by means of a flexible connecting element (26). An angle of inclination (26) is formed between the two printed circuit board parts (22, 24). The first printed circuit board part (22) is attached to the housing (12) by means of a dome (44) which is guided through an opening (46) in the first printed circuit board part (22). The second printed circuit board part (24) is located in a retaining slot (54) of the housing (12). The invention further relates to a radar sensor (8) for a motor vehicle (2).

Description

[0001] The invention relates to an electronic assembly for a motor vehicle, comprising a housing in which a printed circuit board is arranged. The invention further relates to a radar sensor for a motor vehicle.

[0002] Motor vehicles, such as passenger cars, typically have several doors that cover an opening in the vehicle's body. The door is usually mounted to the vehicle's body by means of a hinge, allowing the opening to be opened by adjusting the door. If the door is a side door, this allows access to the vehicle's interior and / or loading items into the interior. For increased convenience, the door is often driven by an electric motor, which also incorporates the door mechanism. When the electric motor is operating, the door is moved along a specific path. This path is determined by the hinge that mounts the door to the vehicle's body.

[0003] It is possible that a user of the electric door opener may not be able to fully see the door's adjustment range surrounding its travel path and, for example, activate the opener even though there is an obstacle within that range. The adjustment range is the area traversed by the door when it is moved along its full travel path, and is defined by the door's outer contour. The shape of this adjustment range is usually stored, at least implicitly, in the electric door opener's memory during manufacturing.

[0004] To prevent the door from colliding with an obstacle, which could damage the obstacle and / or the door, the electric door drive usually includes a collision protection sensor that monitors the adjustment range. If the obstacle is within this range, the electric motor is cut off, preventing the door from moving. In a further development, the door continues to move until the distance to the obstacle reaches a predetermined minimum. When this occurs, the electric motor stops, thus preventing a collision.

[0005] To ensure obstacle detection even in relatively poor lighting conditions and regardless of environmental influences, the collision avoidance sensor typically includes or is formed using a radar sensor. The radar sensor itself comprises an electronic assembly with a circuit board on which a radar antenna and evaluation electronics are mounted. To protect the circuit board from the elements and simplify installation, it is usually housed within a casing.

[0006] A vehicle's outer shell is typically made of sheet metal. However, this metal is usually impervious to the electromagnetic waves generated and received by the radar sensor. Therefore, the radar sensor must be mounted outside the body. This is typically achieved using the door handle, which usually contains a plastic housing. The radar sensor is then installed inside this housing. Consequently, the radar sensor must be relatively small. Furthermore, the circuit board within the housing must be precisely aligned to allow for relatively low tolerances. This increases the complexity of the design and therefore the manufacturing costs.

[0007] The invention is based on the objective of providing a particularly suitable electronic assembly for a motor vehicle and a particularly suitable radar sensor for a motor vehicle, advantageously reducing manufacturing costs.

[0008] With regard to the electronic assembly, this problem is solved according to the invention by the features of claim 1, and with regard to the radar sensor by the features of claim 14. Advantageous further developments and embodiments are the subject of the respective dependent claims.

[0009] The electronic assembly is suitable for, and specifically designed and configured for, a motor vehicle. In other words, the electronic assembly can form an integral part of the motor vehicle when assembled. The motor vehicle is primarily land-based and preferably multi-track. It is advantageously possible to position the motor vehicle essentially freely, particularly on a roadway. For this purpose, the motor vehicle expediently has appropriate wheels. In summary, it is preferably possible to position the motor vehicle on land essentially independently of other conditions. In other words, the motor vehicle is preferably not rail-guided. The motor vehicle is preferably a passenger car or a commercial vehicle, such as a truck or bus.

[0010] The electronic assembly comprises a housing in which a printed circuit board is arranged. The housing is preferably made of plastic and is, for example, an injection-molded plastic part. In particular, the housing is sealed and has a rating of IP 54, IP 64, or IP 68. A terminal is suitably provided in the housing to enable electrical contact with the components located inside.

[0011] The electronic assembly comprises a printed circuit board (PCB) located within the housing. In other words, the PCB is enclosed and protected by the housing. The PCB provides a suitable electronic or electrical circuit. For this purpose, the PCB has, for example, several conductive traces by which multiple electrical and / or electronic components are appropriately interconnected. These components are suitably connected to and electrically contacted by the PCB. Specifically, the electrical and / or electronic components are attached to the PCB by surface mounting and / or through-hole mounting and electrically contacted with it.

[0012] The printed circuit board (PCB) comprises a first PCB section and a second PCB section. The two PCB sections may be identical in construction or, preferably, different. At a minimum, however, both PCB sections are planar. For example, the two PCB sections may be plate-like. In summary, the two PCB sections are located in their respective planes. An angle of inclination exists between the PCB sections and, consequently, between the planes they occupy. In other words, the two planes within which the two PCB sections lie are not parallel but tilted relative to each other. Therefore, the angle of inclination is different from 0° or 180°.

[0013] The two circuit board sections are electrically connected by a flexible connector. Preferably, the two circuit boards are also mechanically connected by this connector, so that the circuit board functions as a single component. This simplifies assembly and arrangement within the housing. Furthermore, it is not necessary to perform an electrical connection between the circuit board sections after they are arranged in the housing. In particular, the two circuit board sections and the connector are permanently joined. At the very least, non-destructive disassembly is either impossible or only possible with considerable effort.

[0014] The first printed circuit board (PCB) section is attached to the housing by means of a dome. The dome is advantageously attached to an inner surface of the housing and, for example, is integrally formed with the housing. To secure the first PCB section to the housing, the dome is guided through an opening in the first PCB section. Specifically, the dome rests against the edge of the opening in the first PCB section, so that at least some movement of the first PCB section in the plane of the first PCB section is prevented by the dome. The second PCB section is inserted into a retaining slot in the housing. Thus, the retaining slot stabilizes the second PCB section relative to the housing and holds it securely in place. The retaining slot is preferably formed by the housing and, for example, integrated into an inner surface of the housing.The retaining slot is suitably designed as a blind hole, which prevents foreign particles from entering the housing.

[0015] For assembly, it is therefore only necessary to insert the second circuit board section into the retaining slot and subsequently, or simultaneously, guide the dome through the opening of the first circuit board section. Since the second circuit board section is mechanically connected to the first circuit board section by means of the connecting piece, the second circuit board section is also indirectly stabilized by the dome, thus preventing any movement of the second circuit board section out of the retaining slot, i.e., its only remaining degree of freedom. Furthermore, the arrangement of the second circuit board within the retaining slot also prevents any movement of the first circuit board section.This involves a relatively precise alignment of the two circuit board parts to each other and to the housing, whereby, due to the different fastening methods of the two circuit board parts, assembly is made easier and can also take place in a relatively confined space.

[0016] Preferably, the spacing between the printed circuit board components, and in particular their minimum distance from each other, is less than 1 cm, 5 mm, 2 mm, or 1 mm. Preferably, the length of the connecting element is adapted accordingly. Consequently, it has a length that is less than 1 cm, 5 mm, 2 mm, or 1 mm. This results in a comparatively compact electronic assembly and reduces material costs.

[0017] For example, the electronic assembly is a component of a control unit, which is, for instance, a component of the main drive system of a motor vehicle and / or is used for its operation. However, it is particularly preferred that the electronic assembly is assigned to an auxiliary unit of the motor vehicle, such as an assistance system or pilot system. It is especially preferred that the electronic assembly is assigned to an electric motor actuator or, more appropriately, to a sensor.

[0018] In particular, the electronic assembly is a component of a radar sensor and, for example, forms the radar sensor itself. It is particularly possible to design this assembly in a relatively small and compact form, while the circuit board components are aligned with relative precision. Each component provides, for example, a directional beam or a monitoring area into which electromagnetic waves are emitted and / or received during operation. Specifically, each of the two circuit board components is assigned one or more radar antennas, allowing the radar sensor to monitor different areas of the room based on the angle of inclination.

[0019] The radar sensor is, for example, integrated into or constitutes a collision protection sensor for an electric door drive. In its installed state, the electronic assembly is typically located within a door handle. Thus, the radar sensor primarily monitors a close-range area around the vehicle, specifically up to a maximum of 2 or 5 meters. Alternatively, the radar sensor can be used to monitor the vehicle's interior, particularly to determine the position of a vehicle occupant. Here, too, the monitoring range is limited to 2 to 5 meters. Another alternative application is the radar sensor's use for detecting traffic on a roadway. In this case, the area monitored by the radar sensor is larger and extends, suitablely, more than 10, 50, or 100 meters away from the vehicle.The wavelength of the electromagnetic waves used, also known as radar waves, is appropriately adapted to the respective application.

[0020] For example, only a single such dome is present. Preferably, several corresponding domes are present, each guided through a corresponding opening in the first circuit board section. This results in a comparatively robust fastening. Consequently, even if one of the domes fails and / or the housing is subjected to vibrations, the first circuit board section, and therefore also the second circuit board section, is always securely positioned within the housing.

[0021] For example, the dome is formed by means of a press fit or at least incorporates one. In other words, the dome features the press fit, which is located within the opening. When the dome is inserted into the opening, the press fit is elastically deformed, so that it fits securely within the opening. Consequently, no additional or even readily available tool is required for fastening, i.e., mounting the dome to the first printed circuit board component; the dome is simply guided through the opening. In particular, the press fit has one or more appropriately designed spring tabs or similar features, which are suitablely made of metal.

[0022] In this further development, electrical contact is also achieved via the press-fit connection, thus increasing functionality and reducing the number of required components. The dome itself is attached to the housing, for example, by being molded onto it, particularly on an inner surface. Alternatively, the housing is injection-molded onto the dome. In another alternative, the dome is, for example, a component of a die-cut grid that is in turn held to the housing. In this case, the die-cut grid is, for example, a component of a connector that passes through the housing. Thus, electrical contact with the circuit board is possible from outside the housing via the die-cut grid and the dome. The connector is preferably associated with the respective connection.

[0023] Alternatively, the dome is hot-stitched to the first circuit board section. In this case, the dome is made of a plastic material, and the free end of the dome, which passes through the openings, is preferably plastically widened, for which purpose these openings are expediently heated. The free end is suitably widened so that the dome has a rivet-like shape. The dome is, for example, molded onto the housing and, in particular, is integral with it. In other words, the dome consists of the same material as the housing. This ensures a secure connection of the dome to the housing and reduces the number of separate components. Furthermore, it is not necessary to additionally stabilize or fasten the dome to the housing.

[0024] For example, the dome on the side of the first PCB section facing away from the free end has essentially the same dimensions as the opening, allowing the first PCB section to be moved along the dome before final fastening. This also makes it possible to compensate for manufacturing tolerances. Alternatively, the dome can be stepped, and the first PCB section rests on the step of the dome. This further stabilizes the first PCB section and reduces or at least limits one degree of freedom of movement without requiring additional work steps. The step of the dome also stabilizes and aligns the first PCB section before final fastening, thus simplifying assembly.

[0025] For example, the first printed circuit board (PCB) section rests flat against a wall or base of the housing. Preferably, the first PCB section is spaced apart from this surface. This allows, for example, electrical and / or electronic components, connected to the first PCB section, to be arranged between the wall / base and the first PCB section. In particular, it is possible to populate both sides of the first PCB section. This improves space utilization and heat dissipation. Adequately, the first PCB section rests at its edge on a step attached to the housing. In this case, the step is integrally formed with other components of the housing and, in particular, with the housing itself. Consequently, the first PCB section is spaced flat from the base / wall of the housing, with the contact area of ​​the step on the first PCB section being comparatively small.

[0026] For example, the first circuit board section is attached to the step. However, it is particularly preferred that it simply rests on the step, which simplifies assembly. Due to the fixing by means of the dome, movement of the first circuit board section relative to the step is then prevented.

[0027] Preferably, the step limits the insertion of the dome into the opening. For assembly, the first circuit board section is placed onto the step, and the dome is guided through the opening during placement. The dome is then hot-stitched, for example, so that it cannot be removed subsequently. The step prevents movement of the first circuit board section in one direction, and the hot-stitched end of the dome prevents movement in the other direction. Thus, the step is not required for the dome itself, allowing it to be manufactured with comparatively high tolerances, while still ensuring a robust connection thanks to the step. For example, only a single such step is present. However, several such steps are particularly preferred, assigned, for example, to different edges or to the same edge.Preferably, two corresponding steps are assigned to each of two opposite edges, so that a comparatively stable support of the first printed circuit board part is achieved.

[0028] For example, the second circuit board section is completely surrounded by the retaining slot, and the second circuit board section rests, for example, flat against the opposite sides of the retaining slot. However, it is particularly preferred that the second circuit board section is only gripped at its edges by the retaining slot. This makes it possible to arrange comparatively large electrical and / or electronic components on the second circuit board section without them being obstructed by the retaining slot.

[0029] For example, the retaining slot engages an end face of the second circuit board section, particularly the end opposite the connecting part. However, it is especially preferred that an edge perpendicular to this edge and / or an edge extending between the end face of the second circuit board section and the end facing the connecting part is engaged. This facilitates the insertion of the second circuit board section into the retaining slot.

[0030] For example, only a single retaining slot is present. However, it is particularly advantageous that the second circuit board section is gripped at opposite ends by a retaining slot on each side. The two retaining slots are advantageously mirror images of each other, which simplifies manufacturing and insertion. Due to the two retaining slots, the second circuit board section is held relatively securely, while still providing a comparatively large amount of space for arranging the electrical / electronic components on the second circuit board section.

[0031] For example, the retaining slot has two parallel flanks that, for instance, engage with the second printed circuit board part by friction or by forming a clearance fit. However, the retaining slot preferably has an insertion ramp. In other words, the two flanks are inclined towards each other and therefore not parallel. Advantageously, the end facing the connecting part is widened to facilitate the insertion of the second printed circuit board part into the retaining slot. Preferably, the insertion ramp is between 1° and 5°. In other words, the two flanks are inclined at an angle between 1° and 5° to each other. This facilitates the insertion of the second printed circuit board part while preventing excessive movement of the second printed circuit board part during assembly.For example, the connecting part and the fastening of the first circuit board part completely prevent such movement.

[0032] For example, the flanks of the retaining slot, i.e., the surfaces facing the second circuit board component, are essentially smooth. This facilitates insertion and manufacturing. Preferably, however, the retaining slot features a crimp rib. Advantageously, several such crimp ribs are present. These ribs are elastically bent, particularly when the second circuit board component is inserted into the retaining slot, thus achieving a frictional connection. This makes it possible to increase the distance between the flanks and / or to use large manufacturing tolerances, while still ensuring a relatively precise position of the second circuit board component within the retaining slot.

[0033] Preferably, the crimp rib is formed by the housing itself, thus eliminating the need for an additional component. Preferably, the crimp rib is integrally formed with one of the flanks of the retaining slot. The crimp rib preferably runs substantially perpendicular to the insertion direction of the second circuit board section into the retaining slot. This ensures that the rib is appropriately bent when the second circuit board section is inserted, and consequently, the second circuit board section is securely held within the retaining slot.

[0034] For example, the angle of inclination between the two connecting parts has a value between 10° and 40° or between 140° and 170°. Particularly preferred, however, is an angle of inclination between 80° and 100°, and preferably equal to 90°. Thus, the circuit board is essentially L-shaped. Preferably, the housing is also essentially L-shaped, which reduces the space requirement. Due to the L-shape, it is possible to monitor different areas using the two circuit board parts if the electronic assembly is a component of the radar sensor. Consequently, its suitability as a radar sensor is improved. Furthermore, the L-shape facilitates the insertion of the circuit board into the housing, and the insertion direction is advantageously parallel to the retaining slot and / or the contour of the dome. Consequently, assembly is simplified.

[0035] For example, the printed circuit board (PCB) is designed as a single piece of flexible circuit board. This board typically features a film, such as a polyamide film, which is provided with conductive traces, for example, printed with a design. This design allows the PCB to be shaped to fit the housing, thus making relatively efficient use of the available installation space.

[0036] In an alternative design, the circuit board components are each made of a glass-fiber reinforced epoxy resin, to which several copper conductors are arranged, particularly on the outside and / or embedded. Consequently, the circuit board components are essentially rigid. This facilitates movement during storage, manufacturing, and / or assembly.

[0037] The connecting element comprises, for example, a conductive film, also known as a foil conductor. In particular, a flexible printed circuit board (PCB) is used as the conductive film. The conductive film is, in particular, a polyamide film provided with one or more conductive traces, preferably printed. The connecting element is attached to the PCB components and electrically connected to them. Preferably, the connecting element is soldered and / or glued to the PCB components, ensuring a relatively stable connection.

[0038] Preferably, however, the printed circuit board is a single piece, and the connecting element and the two circuit board sections are initially designed as a rigid unit. The connecting element is then manufactured by removing, preferably milling, the glass-fiber-reinforced epoxy resin, making it comparatively thin and flexible. For example, only the conductor tracks in the area of ​​the connecting element remain. Thus, the individual components of the circuit board are relatively robustly attached to one another, namely, at least partially integrally formed. Furthermore, manufacturing is simplified. Fewer different materials are also required in this way, and manufacturing costs are reduced. In particular, the circuit board is thus designed as a so-called "semi-flexible" board. For example, the connecting element has only a single layer of conductor tracks, especially a copper layer.However, it is particularly advantageous to have more such layers. This increases robustness. A number of two layers is especially preferred. This allows them to be spaced relatively far apart, preventing the formation of a short circuit, even if no glass fiber reinforced epoxy resin is present in that area.

[0039] For example, the connecting element is located on the sides of the printed circuit board (PCB) sections facing each other due to the angle of inclination. However, it is particularly preferred that the connecting element is located on the opposite sides of the two PCB sections and is attached and / or soldered and / or integrally formed there. Consequently, the bending radius of the connecting element is increased, thus preventing kinking. For example, each PCB section terminates at the connecting element. Particularly preferred is at least one of the PCB sections, preferably the second, extending beyond the connection point of the connecting element. This allows for mechanical engagement and therefore insertion into the retaining slot, thereby reducing stress on the connecting element. This also increases the usable area of ​​the second PCB section.

[0040] For example, the housing is a single piece, injection-molded around the printed circuit board. Alternatively, the housing is composed of several different components. Preferably, however, the housing comprises a shell and a lid, with the housing being formed by means of these components. The lid is placed on and secured to an edge of the shell. A seal is suitably arranged between the lid and the edge. For example, the lid is detachably attached to the shell or, preferably, permanently. In particular, the lid is welded to the shell to prevent the ingress of foreign particles. The lid facilitates the placement of the printed circuit board within the housing. It is also possible to manufacture the shell and lid separately from the printed circuit board.

[0041] For example, the lid is three-dimensional and has several raised sections. However, it is particularly preferred that the lid be flat, and thus essentially arranged in only one plane. This results in a comparatively small footprint and simplifies assembly. It also facilitates storage. The tray itself is, for example, cuboid or, advantageously, L-shaped. In particular, the tray is shaped according to the angle of inclination. Preferably, the dome and / or the retaining slot are associated with the tray. Thus, during assembly, the circuit board is advantageously first inserted into the tray and secured there. Subsequently, the tray is closed with the lid, thereby completing the electronic assembly.

[0042] In the assembled state, the first circuit board section is advantageously arranged parallel to the lid. The retaining slot is preferably positioned substantially perpendicular to the lid. For assembly, the second circuit board section is inserted into the retaining slot, with the first circuit board section oriented perpendicular to the retaining slot. The dome is suitably positioned perpendicular to the first circuit board section and is guided through the opening of the first circuit board section when the circuit board is inserted into the housing. Thus, securing the circuit board in the housing requires only moving the circuit board in a single direction. This reduces the number of required work steps and the space required. Precise alignment of the circuit board within the housing is still achieved.

[0043] For example, the housing contains only the circuit board. Heat dissipation can occur directly through the housing, or a heat sink can be integrated into the housing, extending to an outer surface. A heat sink is particularly preferred within the housing. Specifically, the heat sink is formed from a sheet metal component, thus reducing manufacturing costs. The heat sink is, for example, essentially flat, or expediently angled. The heat sink is also preferably angled. This improves space utilization by reducing the required installation space, while still providing a comparatively large mass and surface area for the heat sink. In particular, the heat sink rests flat against an inner surface of the housing, enabling heat dissipation through the housing.Preferably, the heat sink is thermally contacted with both circuit boards. For thermal contact, the heat sink, for example, rests directly against the circuit board components. Preferably, however, the heat sink is thermally connected to the two circuit board components by means of thermal paste and / or a thermal pad. For example, the heat sink is also electrically contacted with at least one of the two circuit board components, which improves heat transfer. Preferably, however, the heat sink is electrically insulated from the circuit board components, which increases safety. Furthermore, the formation of an unwanted short circuit and / or functional impairment is prevented.

[0044] The radar sensor is suitable for, and in particular designed and configured for, a motor vehicle. In other words, the radar sensor preferably forms an integral part of the motor vehicle when installed. The motor vehicle is, for example, a commercial vehicle such as a truck or bus. Preferably, however, the motor vehicle is a passenger car. For example, the radar sensor serves to detect other road users, for instance, as part of an assistance system or a pilot system. Preferably, however, the radar sensor is used as a collision protection sensor for an electric door drive or the like. Alternatively or in combination with this, the radar sensor is used to monitor the interior of the motor vehicle, in particular to determine the position of a person using the motor vehicle within the interior.

[0045] The radar sensor comprises an electronic assembly consisting of a housing containing a printed circuit board (PCB). The PCB has a flat first section and a flat second section, which are electrically connected by a flexible connector. An angled connection is formed between the two PCB sections. The first PCB section is attached to the housing by means of a boss that passes through an opening in the first PCB section, and the second PCB section rests in a retaining slot in the housing.

[0046] The radar sensor comprises a radar antenna assigned to one of the two circuit board sections. For example, the radar antenna can be formed by an electrical coil or, preferably, by a conductive trace. This reduces manufacturing costs. For instance, only a single radar antenna is required. However, it is particularly preferred that each of the two circuit boards has its own radar antenna, which increases the area monitored by the radar sensor due to the angle of inclination. The radar sensor also suitably includes evaluation electronics. These are arranged, for example, outside the housing, or, more preferably, inside the housing. In particular, the evaluation electronics are formed by several electrical and / or electronic components that are suitably interconnected. Advantageously, the interconnection is carried out using one of the circuit board sections to which the components are also attached.Preferably, several radar antennas are assigned to each circuit board section.

[0047] Furthermore, the invention relates to a motor vehicle with a corresponding electronic assembly and / or a corresponding radar sensor.

[0048] The further training and advantages explained in connection with the electronics assembly can also be applied analogously to the radar sensor / the motor vehicle and to each other, and vice versa.

[0049] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. The drawing shows: Fig. 1 Schematic side view of a motor vehicle with a radar sensor which includes an electronic assembly, Fig. 2, Fig. 3. A variant of the electronic assembly is shown in a sectional or perspective view. Fig. 4 in a further sectional view a part of the electronic assembly, Fig. 5-7 schematically in a sectional view different designs of a dome, Fig. 8 in another sectional view a part of the electronic assembly, and Fig. 9 according to Fig. 2 a final variant of the electronic assembly.

[0050] Corresponding parts are marked with the same reference symbols in all figures.

[0051] In Fig. Figure 1 schematically simplifies the representation of a motor vehicle 2 in the form of a passenger car. The motor vehicle 2 has several wheels 4, which make contact with a road surface (not shown in detail). The wheels 4 are connected to the body 6 of the motor vehicle 2 by means of a chassis. The body has an opening (not shown in detail) that can be covered by a side door. The side door is part of an electric door drive, allowing the side door to be electrically adjusted relative to the body 6.

[0052] To prevent the side door from being obstructed by an obstacle, the electric door drive has a collision protection sensor integrated into a door handle (not shown) or a trim strip. The collision protection sensor is designed as a radar sensor 8, which is shown schematically in a sectional view. The radar sensor 8 is formed by an electronic assembly 10, which has a housing 12 made of plastic. The housing 12 comprises an L-shaped shell 14, which is completely closed by a flat cover 16. Thus, the housing 12 is also L-shaped, and the cover 16 forms one side of the housing 12. The cover 16 and the shell 14 are each made of the same or different plastic using a plastic injection molding process and are welded or bonded together by plastic welding.

[0053] A printed circuit board 18 is arranged within the housing 12. The printed circuit board 18 is designed as a flexible printed circuit board 20 and thus consists essentially of a polyamide film onto which several conductive traces are printed. A first printed circuit board part 22 and a second printed circuit board part 24 are provided by means of the printed circuit board 18, each of which is essentially flat and forms the opposite ends of the printed circuit board 18. To achieve the flat design, stabilizing elements (not shown in detail) are, for example, arranged, or the edges of the polyamide film are slightly angled.

[0054] A flexible connecting element 26 is formed between the two printed circuit board sections 22 and 24 by means of the flexible printed circuit board 20. Since the flexible printed circuit board 20 is a single piece, the connecting element 26 is electrically and mechanically connected to the two printed circuit board sections 22 and 24. The connecting element 26 is curved, so that an angle of inclination 28 is formed between the two printed circuit board sections 22 and 24. In the example shown, this angle is essentially 90° and is therefore between 80° and 100°. Consequently, the first printed circuit board section 22 runs essentially parallel to the cover 16, and the second printed circuit board section 24 is perpendicular to it.

[0055] Each of the two circuit board sections 22, 24, facing away from each other, is assigned a radar antenna 30, which is formed by a conductor track of the respective circuit board section 22, 24, i.e., the respective copper structure. On the side of the first circuit board section 22 facing the second circuit board section 24, several electrical and / or electronic components 32 are arranged, forming an electrical circuit. This circuit operates the radar antennas 30, in particular by exciting them to emit radar waves and / or monitoring an electrical voltage applied to the radar antenna 20, which is caused by received radar waves. Due to the tilt angle 28, the radiation directions of the radar waves provided by the radar antennas 30 during operation and / or their reception direction are perpendicular to each other, so that the area monitorable by the radar sensor 8 is comparatively large.In one variant not shown in detail, the printed circuit board parts 22, 24 are fitted on both sides with the electrical and / or electronic components 32.

[0056] In Fig. 2 is shown in a sectional view and in Fig. Figure 3 shows a perspective view of a modified version of the electronic assembly 10, in which only the printed circuit board 18 is changed. This board is no longer formed by the flexible printed circuit board 20, but rather the two printed circuit board parts 22 and 24 are made of a glass fiber reinforced epoxy resin. Thus, the two printed circuit board parts 22 and 24 are rigid. The connecting part 26 also had a glass fiber reinforced epoxy resin, which was integral with that of the two printed circuit board parts 22 and 24, as were the conductive traces or at least a copper layer providing the conductive traces. By at least partially, or preferably completely, removing the glass fiber reinforced epoxy resin from the connecting part by milling, it is now flexible and only has the conductive traces 34.In the example shown, two strips 36 are formed by means of the conductor tracks 34, which are assigned to the opposite (lateral) edges of the two printed circuit board parts 22, 24.

[0057] The first printed circuit board part 22 is essentially rectangular and arranged parallel to the cover 16. The second printed circuit board part 24 is also essentially rectangular, but has a projection 38 on the edge facing the first printed circuit board part 22, which is arranged between the two strips 36. Thus, the second printed circuit board part 24 is T-shaped.

[0058] As in Fig. As shown in another sectional view (Figure 4), the connecting part 26 is assigned to and attached to the opposite sides of the two circuit board parts 22 and 24, and electrically contacted with them by means of soldering. Thus, the circuit board 18 is considered a single component.

[0059] A heat sink 40 is arranged within the housing 12. It is made from a sheet metal piece bent at an angle 28. The heat sink 40 is thus L-shaped and positioned on the facing sides of the two circuit board parts 22, 24. The two legs of the heat sink 40 lie flat against the inside of the shell 16. Each leg of the heat sink 40 is parallel to, but spaced apart from, one of the circuit board parts 22, 24. Each leg of the heat sink 40 has a protrusion 42 formed by deep drawing. Each circuit board part 22, 24 is thermally connected to this protrusion via an electrically insulating thermally conductive material, such as a thermal pad (not shown). The thermally conductive material is in direct mechanical contact with the heat sink 40 and the respective circuit board part 22, 24.

[0060] For the secure fastening of the circuit board 18 in the housing 12, second domes 44 are provided, of which in Fig. Only one is shown. The domes 44 are integrally formed on an inner side of the shell 14, with the heat sink 40 located between them. The domes 44 run perpendicular to the first circuit board section 22 and are guided through a respective opening 46 in the first circuit board section 22. Thus, the first circuit board section 22 has a total of two such openings 46.

[0061] In Fig. Figure 5 shows a schematic cross-sectional view of a first variant of the dome 44. This dome is essentially hollow and cylindrical, with one end face integrally formed with the shell 14. The opposite end, located on the side of the first circuit board part 22 facing the cover 16, is plastically widened, specifically by hot-stitching. In summary, the dome 44 is essentially cylindrical when the shell 14 is manufactured, and after passing it through the opening 46, the dome 44 is widened by hot-stitching. Thus, the dome 44 is hot-stitched to the first circuit board part 22.

[0062] To prevent the first printed circuit board section 22 from adhering uncontrollably to the wall of the shell 14, on which the domes 44 are molded, two steps 48 are molded onto each of two opposite and perpendicular walls of the shell 14, extending into the interior of the housing 12. The first printed circuit board section 22 rests on these steps at its edges. Detachment from the steps 48 is prevented by hot-stitching to the domes 44.

[0063] In Fig. Figure 6 shows a schematic cross-sectional view of a modified dome 44, which, as in the previous example, is arranged essentially perpendicular to the first circuit board section 22 and is located on the inside of the shell 14. Compared to the previous embodiment, the dome 44 now has a circumferential step 50, so that the dome 44 is formed by means of two stacked cylinders with different diameters arranged along the same axis. The first circuit board section 22 rests on the step 50 of the dome 44, and the end of the dome 44, which passes through the opening 46, is again hot-stitched. Thus, the first circuit board section 22 is held relatively stably to the housing 12 by means of the dome 44.

[0064] In Fig. Figure 7 shows a further embodiment of the dome 44, schematically depicted in a sectional view. This dome again features the cylindrical section that is integrally formed on the inside of the shell 14 and runs perpendicular to the cover 16. The first printed circuit board section 22 rests on this section. A press-fit connector 52 is attached to the cylindrical section, partially embedded within it and projecting towards the cover 16. The press-fit connector 52 is guided through the opening 46 and elastically deformed. In summary, the dome 44 incorporates the press-fit connector 52, which is positively engaged within the opening 46. Consequently, the first printed circuit board section 22 is stably held by the dome 44, which in turn is attached to the housing 12.

[0065] In summary, regardless of the specific design of the dome 44, the first circuit board section 22 is attached to the housing 12, specifically to the shell 16, by means of the domes 44. For this purpose, each dome 44 is guided through the corresponding opening 46 of the first circuit board section 22.

[0066] The second circuit board part 24 is inserted at its edge into a retaining slot 54, one of which is in Fig. Figure 8 shows the diagram. Each of the retaining slots 54 is assigned to opposite edges of the second circuit board part 24. These slots run essentially perpendicular to the cover 16 and are formed by opposing side walls of the shell 16. The retaining slots 54 are mirror images of each other and each has two flanks 56 that correspond to opposite sides of the second circuit board part 24. These flanks are inclined to each other at an angle of 3°. Consequently, each retaining slot 54 has an insertion angle of between 1° and 5°, specifically 3°.

[0067] On one of the two flanks 56, several crimp ribs 58 of the respective retaining slot 54 are arranged, such that the retaining slot 54 has the crimp ribs 58. These are elastically deformed due to the contact of the edge of the second printed circuit board part 24, so that the second printed circuit board part 24 is held force-fit between the flanks 56.

[0068] In summary, the second circuit board part 24 is thus gripped at opposite edges by means of one of the retaining slots 54 each. Between the retaining slots 54, however, the second circuit board part 20 is free from contact with the shell 16. Consequently, the second circuit board part 24 lies in the retaining slots 54 of the housing 12.

[0069] For the assembly of the electronics module 10, the tray 14 is first provided, which already has the two retaining slots 54 with the respective crimp ribs 58, the correspondingly designed domes 44 and the steps 48. Then the heat sink 40 is placed in the tray 14 and, for example, glued in place. Any thermal pads are already attached to the heat sink 40.

[0070] The printed circuit board 18 is then provided, comprising the two circuit board parts 22 and 24 and the connecting part 26. The printed circuit board 18 is either designed as a flexible circuit board 20, or the two circuit board parts 22 and 24 are made of glass fiber reinforced epoxy resin. The printed circuit board 18 is already bent to achieve the desired tilt angle 28.

[0071] The circuit board is then inserted into the tray 14, whereby one end face of the second circuit board part 24 dips into the retaining slots 54 with its opposite edges, thus guiding the circuit board 18 appropriately. Due to the overhang 38, a point of engagement is provided, which simplifies the insertion of the second circuit board part 24. The circuit board 18 is designed as a flexible circuit board 20, as shown in Fig. As shown in Figure 1, assembly is carried out in a similar manner. Care must be taken when inserting the second circuit board part 24 to ensure that it does not become misaligned.

[0072] As the second circuit board section 24 is moved further in the retaining slots 44, the domes 44 begin to move into the corresponding opening 46. Since the inclination angle 28 is already predetermined by the connecting part 26, alignment of the first circuit board section 22 is not necessary.

[0073] The insertion of the circuit board 18 is stopped when the first circuit board section 22 rests on the steps 48. The domes 44 are then hot-stitched, if necessary. The retaining slots 54 prevent movement in any other direction that could lead to excessive stress on the domes 44. Consequently, the circuit board 18 is held securely within the housing 12. The shell 14 is then closed using the lid 16.

[0074] In Fig. 9 is a modification of the electronic assembly 10 shown in a sectional view, which is essentially the same as in Fig. The embodiment shown in Figure 2 corresponds to the design shown. The domes 44 are again present, but not shown, and one of the aforementioned embodiments is chosen for them. Compared to the previous embodiment, however, the inclination angle 28 is slightly smaller. The heat sink 40 is also shortened. Otherwise, however, the embodiment corresponds to that shown in Figure 2. Fig. 2nd variant shown.

[0075] The invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the individual embodiments can also be combined with one another in other ways without departing from the subject matter of the invention. Reference symbol list 2 motor vehicles 4-wheeler 6 Motor vehicle 8 radar sensor 10 Electronic assembly 12 cases 14 bowls 16 lids 18 circuit boards 20 flexible printed circuit boards 22 first circuit board section 24 second circuit board part 26 Connecting part 28 tilt angles 30 radar antenna 32 electrical / electronic component 34 conductor track 36 strips 38 Overhang 40 heat sinks 42 Bulge 44 Cathedral 46 Opening 48th level Step 50 of the cathedral 52 Pressfit 54 retaining slots 56th flank 58 squashed ribs

Claims

[1] Electronic assembly (10) for a motor vehicle (2), comprising a housing (12) in which a printed circuit board (18) is arranged, which has a flat first printed circuit board part (22) and a flat second printed circuit board part (24) which are electrically connected to each other by means of a flexible connecting part (26), - wherein an angle of inclination (26) is formed between the two printed circuit board parts (22, 24), - wherein the first printed circuit board part (22) is attached to the housing (12) by means of a dome (44) which is guided through an opening (46) of the first printed circuit board part (22), and - wherein the second printed circuit board part (24) is located in a retaining slot (54) of the housing (12). [2] Electronic assembly (10) according to claim 1, characterized by , that the dome (44) has a press fit (52). [3] Electronic assembly (10) according to claim 1, characterized by , that the dome (44) is hot-stitched to the first circuit board part (22). [4] Electronic assembly (10) according to any one of claims 1 to 3, characterized by , that the first printed circuit board part (22) rests on a step (48) attached to the housing (12) at its edge. [5] Electronic assembly (10) according to any one of claims 1 to 4, characterized by , that the second circuit board part (24) is enclosed at the edge by means of the retaining slot (45). [6] Electronic assembly (10) according to claim 5, characterized by , that the second printed circuit board part (24) is enclosed at opposite edges by means of a retaining slot (54) on each side. [7] Electronic assembly (10) according to any one of claims 1 to 6, characterized by , that the retaining slot (54) has an insertion chamfer between 1° and 5°. [8] Electronic assembly (10) according to any one of claims 1 to 7, characterized by , that the retaining slot (54) has a crush rib (58). [9] Electronic assembly (10) according to any one of claims 1 to 8, characterized by, that the angle of inclination (28) is between 80° and 100°. [10] Electronic assembly (10) according to any one of claims 1 to 9, characterized by , that the printed circuit board (18) is formed in one piece as a flexible printed circuit board (20). [11] Electronic assembly (10) according to any one of claims 1 to 9, characterized by , that the printed circuit board parts (22, 24) are made of a glass fiber reinforced epoxy resin, and that the connecting part (26) is assigned to the opposite sides of the two printed circuit board parts (22, 24). [12] Electronic assembly (10) according to any one of claims 1 to 11, characterized by , that the housing (12) has a shell (14) closed by means of a flat cover (16) which is parallel to the first circuit board part (22). [13] Electronic assembly (10) according to any one of claims 1 to 12, characterized by, that a heat sink (40) is arranged in the housing (12), which is thermally contacted with both circuit board parts (22, 24). [14] Radar sensor (8) for a motor vehicle (2), comprising an electronic assembly (10) according to one of claims 1 to 13, wherein one of the two circuit board parts (22, 24) is assigned a radar antenna (30).

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