Radar device for a vehicle

Abstract

Radar device (10) for a vehicle, comprising: - a tub-shaped housing (7) which can be closed by a housing cover (8), - a first printed circuit board (4) arranged in the housing (7) and positioned by means of contact elements (7d) relative to a housing base (7c) for receiving an antenna and high-frequency components (HF), - a second printed circuit board (5) for accommodating low-frequency components (NF), and - a frame part (2) with a shielding surface (2b), wherein the frame part (2) lies flat against the first printed circuit board (4), characterized in that - a spring frame (1) is provided with a spring-elastic property perpendicular to the shielding surface (2b), and - the spring frame (1) is designed to be supported in a spring-biased manner on the one hand against the second printed circuit board (5) fixed in position in the housing (7) and on the other hand against the shielding surface (2b) of the frame part (2), wherein the first printed circuit board (4) which is spring-loaded via the frame part (2) is held pressed against the contact elements (7d) of the housing (7).

Description

[0001] The invention relates to a radar device for a vehicle according to the preamble of patent claim 1.

[0002] Radar systems for vehicles are known from the state of the art and are used, for example, to determine the distance to vehicles ahead.

[0003] A radar device of this type is known from DE 10 2007 042 173 A1, in which two circuit boards are housed in a tub-shaped housing: one circuit board with a radar antenna and high-frequency components (high-frequency circuit board) and another circuit board with low-frequency components (low-frequency circuit board). The bottom of the tub-shaped housing is designed as a radome.

[0004] The two circuit boards of this known radar device are connected to a carrier by means of screws and then inserted into the housing with this carrier, which is closed with a housing cover. The carrier for the two circuit boards consists of a frame part enclosing a shielding surface, the radome-side end of which has a support surface for the first circuit board, with ribs formed on the shielding surface forming chambers together with the shielding surface and the first circuit board. On the opposite side of the carrier, the additional circuit board is inserted into the frame part and screwed to the carrier, so that a plug connection to the first circuit board can be established simultaneously via an opening in the shielding surface.

[0005] This carrier with the two circuit boards is inserted into the housing so that the frame part rests on the support posts located at the corner of the housing, forming a support plane, and can be screwed to these support posts. When the carrier is inserted into the housing, contact pins of a front-end connector, designed as press-in contacts, are pressed into corresponding connection holes on the second circuit board for electrical contact.

[0006] The radar frequencies used for such radar systems are 24 GHz or 77 GHz, but the problem is that the distance between the antenna arranged on the front of the high-frequency circuit board and the housing base designed as a radome is tolerance-critical.

[0007] Furthermore, the use of the press-fit contact pin technology for contacting the low-frequency circuit board via a connector in a vertical direction to the circuit board is equally tolerance-critical due to process-related specifications. Therefore, these two circuit boards, i.e., the high-frequency circuit board and the low-frequency circuit board, arranged at a distance from one another, must be precisely positioned vertically.

[0008] In the known radar device according to DE 10 2007 042 173 A1, this is solved by fixing the two circuit boards in the carrier to the carrier by means of corresponding support planes and screwing them to the carrier. A disadvantage, however, is that the support planes of the carrier must meet tight tolerances relative to one another, particularly with regard to the position of the low-frequency circuit board relative to the connector's press-in pins.

[0009] From EP 2 034 328 A1 a radar sensor is known in which two electrically connected circuit boards are detachably arranged on a metallic carrier.

[0010] Furthermore, DE 10 2005 033 592 A1 describes a carrier for receiving an antenna amplifier with a printed circuit board and locking means as well as cooperating spring means for fixing the printed circuit board to the carrier.

[0011] Based on this prior art, it is the object of the invention to provide a radar device of the type mentioned at the outset, with which a defined distance between the radome of the radar device and the circuit board carrying the radar antenna as well as a defined position of the two circuit boards is ensured.

[0012] This object is achieved by a radar device having the features of patent claim 1.

[0013] Such a radar device for a vehicle, which comprises a trough-shaped housing which can be closed by a housing cover, a first printed circuit board arranged in the housing and positioned by means of contact elements relative to a housing base for receiving an antenna and high-frequency components, a second printed circuit board for receiving low-frequency components, and a frame part with a shielding surface, wherein the frame part lies flat against the first printed circuit board, is characterized according to the invention in that - a spring frame is provided with a spring-elastic property perpendicular to the shielding surface, and - the spring frame is designed to be supported in a spring-biased manner on the one hand against the second printed circuit board fixed in position in the housing and on the other hand against the shielding surface of the frame part, wherein the first printed circuit board, which is spring-loaded via the frame part, is held pressed against the contact elements of the housing.

[0014] The problems listed above are solved according to the invention in a surprisingly simple and thus cost-effective manner in that a spring-elastic spring frame is arranged between the second circuit board carrying the low-frequency components, i.e. the low-frequency circuit board, and the shielding surface of the frame part, whereby a tolerance compensation takes place between this second circuit board and the frame part and the first circuit board is pressed by the spring frame against its contact elements under spring force and thus a precisely defined distance to the housing base, which is preferably designed as a radome, is maintained.

[0015] Furthermore, the position of the second circuit board, i.e. the low-frequency circuit board, is also precisely defined, since it is arranged in a fixed position in the housing and thus the tolerance requirements for the contact pins of a connector designed as press-in contacts for electrically contacting the second circuit board can be met.

[0016] The spring frame inserted into the frame part can thereby be brought into its spring-preloaded state, since according to the further development the spring frame is designed in such a way that in the non-spring-preloaded state the front edge of the frame part is projected over by the spring frame.

[0017] In one embodiment of the invention, the housing has a contact surface for fixing the position of the second circuit board, which is projected over by the spring frame when the latter is not in the spring-loaded state. This enables simple and reliable assembly of the radar device, since when the housing cover is mounted on the tub-shaped housing, the second circuit board is pressed against its contact surface, and the spring frame is brought into its spring-loaded state via contact with the spring frame.

[0018] In one embodiment of the invention, the spring frame is formed with a U-shaped cross-section perpendicular to the shielding surface of the frame part, with one leg section of the U-shape of the spring frame forming a support surface for the second circuit board. This distributes the spring-elastic effect of the spring frame evenly across the second circuit board, thus avoiding tension between the second circuit board and the frame part.

[0019] It is particularly advantageous if, according to a further development, the leg section of the U-shape of the spring frame resting on the shielding surface is designed to be resilient, preferably with spring tabs, the spring tabs resting resiliently on the shielding surface.

[0020] In order to connect the two circuit boards via a plug and a socket, the shielding surface of the frame part has an opening which accommodates the plug connection.

[0021] According to a further development, the spring frame can be manufactured as a sheet metal part, particularly cost-effectively. Furthermore, the frame part is advantageously manufactured as a single piece with the shielding surface, preferably as a metal casting, e.g., from cast aluminum.

[0022] The invention is described in detail below using an exemplary embodiment with reference to the accompanying figures. They show: Fig. 1 is an exploded view of a radar device according to the invention, Fig. 2 a perspective view of a frame part with inserted spring frame of the radar device according to Fig. 1, Fig. 3 an exploded view of the frame part and the spring frame according to Fig. 2, Fig. 4 a top view of the frame part with the inserted spring frame according to Fig. 2, Fig. 5 a sectional view according to section AA of the frame part with inserted spring frame according to Fig. 4, Fig. 6 a perspective view of the radar device according to Fig. 1 in the assembled state, and Fig. 7 a sectional view according to section BB of the radar device according to Fig. 6.

[0023] The Fig. 6 The radar device 10 shown fully assembled consists of Fig. 1 from a tub-shaped housing 7 with side walls 7a and 7b connected via a housing base 7c and a housing cover 8. This housing 7 accommodates a first printed circuit board 4 with high-frequency components HF and a second printed circuit board 5 with low-frequency components NF, which is arranged at a distance therefrom by a frame part 2 and a spring-elastic spring frame 1, as can be seen from Fig. 7. Therefore, the first circuit board 4 is also referred to below as a high-frequency circuit board, and the second circuit board 5 is also referred to as a low-frequency circuit board. The high-frequency circuit board 4 carries not only high-frequency components (HF) on the side facing away from the housing base, but also high-frequency components (HF) and a radar antenna on the housing base side, with these high-frequency components being shielded by a shield 6. The housing base 7c of the housing 7 is designed as a radome.

[0024] The parallel side walls 7a of the housing 7 are designed as longitudinal side walls, and its parallel side walls 7b are designed as transverse side walls. A connector socket 9 is formed on a transverse side wall 7b, the connector contacts of which are guided into the housing 7 and terminate there in press-in pins 9a, bent at right angles. This area with the press-in pins 9a is separated from the rest of the housing by a further transverse side wall 7b' running parallel to the transverse side wall 7b containing the connector socket. Furthermore, post-like contact elements 7d are formed in the edge region of the housing base 7c of the housing 7, each of which forms a support surface for the first printed circuit board 4 to be inserted into this housing 7.

[0025] The frame part 2 according to Fig. 3 is made in one piece from die-cast aluminum for the purpose of good heat dissipation and comprises a rectangular frame 2a formed essentially from side parts 2c with a shielding surface 2b arranged therein and a stepped partial surface 2b'. The frame 2a formed with the side parts 2c is matched with its external dimensions to the housing 7 such that, after the first circuit board 4 rests on the contact elements 7d, it can also be inserted into the housing 7, so that the housing-bottom end faces 2e of the side parts 2c rest all the way around the edges of this first circuit board 4. This circuit board side with the high-frequency components HF is thus covered in a hood-like manner by the shielding surface 2b and the side parts 2c, whereby the high-frequency components HF are electromagnetically shielded.

[0026] Furthermore, according to Fig. 4 the shielding surface 2b of the frame part 2 has an opening 2f which serves to receive a plug connection so that the second circuit board 5 resting on the end face 2d of the side parts 2c of the frame 2a can be connected to the first circuit board 4 via this plug connection.

[0027] From the side facing the housing cover, a spring frame 1 with a spring-elastic property acting in a direction perpendicular to the shielding surface 2b is inserted into this frame part 2. The frame of this spring frame 1 has a U-shaped cross-section, so that the two legs 1a and 1b of the U-shape point inwards and the outer dimensions are selected such that the spring frame 1 can be inserted into the frame 2a of the frame part 2, with the leg 1b of the U-shape resting on the shielding surface 2b. The height of this spring frame 1 is selected such that the leg 1a forming a support surface for the second printed circuit board 5 is slightly overhanged by the surface of the leg 1a by the dimension a, as can be seen in particular from Fig. 2 and Fig. 5 can be seen.

[0028] To realize the spring-elastic property of the spring frame 1, the leg 1b of the U-shape resting on the shielding surface 2b is designed with spring-elastic spring tabs 1c which are inclined outwards with respect to the U-shape, so that the spring frame 1 rests resiliently on the shielding surface 2b via these spring tabs 1c.

[0029] The assembly of the radar device 10 begins with the high-frequency circuit board 4 being inserted into the housing 7 so that it rests on the contact elements 7d arranged at the corners of the housing 7. This first circuit board 4 has a length in the direction of the longitudinal side walls 7a such that the press-in pins 9a of the socket 9 are guided past this first circuit board 4 and therefore this first circuit board 4 can be inserted in this area into the space formed by the further transverse side wall 7b' and the side walls 7a and 7b, as can be seen from Fig. 7 is recognizable.

[0030] Subsequently, the frame part 2 with the inserted spring frame 1 is placed on the first circuit board 2, so that the front edge 2e of the frame part 2 rests all the way around the edge of this first circuit board 4. The components involved are dimensioned such that the leg 1a of the spring frame 1, which serves as a support surface for the second circuit board 5, slightly projects beyond a support surface 7e arranged on the side walls 7a and 7b or 7b' of the housing 7.

[0031] The low-frequency circuit board 5 is now placed on the leg 1a of the spring frame 1 serving as the contact surface. This circuit board 5 extends with an edge region 5a over the area separated from the transverse side wall 7b'. When this low-frequency circuit board 5 is inserted into the housing 7, the press-in pins 9a are partially pressed into the press-in openings of the second circuit board 5 located in the region 5a. This second circuit board 5 is thus longer by this region 5a than the first circuit board 4. In this state, there is a small distance between this second circuit board 5 and the circumferential contact surface 7e on the side walls 7a and 7b or 7b' of the housing 7.

[0032] To close the housing 7, the housing cover 8 is placed on the second circuit board 5 or the side walls 7a and 7b of the housing 7 and screwed to the corners of the housing 7 by means of screws 8c, so that according to Fig.7, the second circuit board 5 is thereby pressed onto the contact plane 7e by a circumferential web 8a of the housing cover 8 and fixed in this position, and at the same time, the spring frame 1 is compressed, generating a spring force, since the first circuit board 4 rests against the contact elements 7d and thus serves as a counterbearing. In addition, during this assembly process, the press-in pins 9a are also pressed into their final position in the press-in openings in the area 5a of the second circuit board 5.

[0033] In the closed state of the housing 7, i.e. when the second circuit board 5 rests against the contact surface 7e due to the screw connection of the housing cover 8 to the housing 7, the spring frame 1 is in the prestressed state, so that the first circuit board 4 is pressed against the contact elements 7d.

[0034] The radar device 10 mounted in this way is mounted to the vehicle body of a vehicle via mounting screws 8d mounted on the housing cover 8.

[0035] The housing 7 can be designed as a plastic housing, with the housing cover 8 being metallic or a metallized plastic cover, so that even in the assembled state, low-frequency components NF arranged on the housing cover-side circuit board of the second circuit board 5 are also electromagnetically shielded. Such a housing cover 8 is equipped with cooling fins 8b on its outer side for improved heat dissipation. Reference symbol 1 spring frame 1a Leg of the U-shaped spring frame 1 1b Leg of the U-shaped spring frame 1 1c Spring tabs of leg 1b 2 frame part 2a Frame of the frame part 2b Shielding surface of the frame part 2b' Partial area of the shielding surface 2b 2c Side parts of the frame 2a 2d front edge, front surface of the frame part 2e front edge, front surface of the frame part 2f Opening in the shielding surface 2a 4 first circuit board, high-frequency circuit board 5 second circuit board, low frequency circuit board 5a Edge area of the circuit board 5 with press-in openings 6 Shielding 7 Radar device housing 7a Side wall, long side wall of the housing 7 7b Side wall, transverse side wall of the housing 7 7b' Side wall, transverse side wall of the housing 7 7c Case bottom of case 7 7d Housing elements 7 7e Contact surface of the housing 7 8 Housing cover of the housing 7 8a circumferential web of the housing cover 8 8b Cooling fins of the housing cover 8 8c screw 8d mounting screws 9 socket 9a Press-in pins of the plug socket 9 10 Radar device

Claims

[1] Radar device (10) for a vehicle, comprising: - a tub-shaped housing (7) which can be closed by a housing cover (8), - a first printed circuit board (4) arranged in the housing (7) and positioned by means of contact elements (7d) relative to a housing base (7c) for receiving an antenna and high-frequency components (HF), - a second printed circuit board (5) for accommodating low-frequency components (NF), and - a frame part (2) with a shielding surface (2b), wherein the frame part (2) lies flush against the first printed circuit board (4), characterized by , that - a spring frame (1) is provided with a spring-elastic property perpendicular to the shielding surface (2b), and - the spring frame (1) is designed to be supported in a spring-biased manner on the one hand against the second printed circuit board (5) fixed in position in the housing (7) and on the other hand against the shielding surface (2b) of the frame part (2), wherein the first printed circuit board (4) which is spring-loaded via the frame part (2) is held pressed against the contact elements (7d) of the housing (7). [2] Radar device (10) according to claim 1, characterized by that the spring frame (1) is designed to project beyond the front edge (2d) of the frame part (2) in the non-spring-preloaded state. [3] Radar device (10) according to claim 1 or 2, characterized by that the housing (7) has a contact surface (7e) for fixing the position of the second printed circuit board, which contact surface is projected over by the spring frame (1) in the non-spring-biased state. [4] Radar device (10) according to claim 3, characterized bythat the housing cover (8) is designed to close the housing (7) with the second printed circuit board (5) resting on its contact surface (7e). [5] Radar device (10) according to one of the preceding claims, characterized by that the spring frame (1) is formed perpendicular to the shielding surface (2a) of the frame part (2) with a substantially U-shaped cross-section, wherein a leg section (1a) of the U-shape of the spring frame (1) forms a support surface for the second printed circuit board (5). [6] Radar device (10) according to claim 5, characterized by that the leg section (1b) of the spring frame (1) resting on the shielding surface (2a) is resilient, preferably with spring tabs (1c), wherein the spring tabs (1c) rest resiliently on the shielding surface (2b). [7] Radar device (10) according to one of the preceding claims, characterized by that the housing base (7c) of the housing (7) of the housing (7) is designed as a radome. [8] Radar device (10) according to one of the preceding claims, characterized by that the shielding surface (2b) has an opening (2f) which accommodates a plug connection for electrically connecting the two circuit boards (4, 5). [9] Radar device (10) according to one of the preceding claims, characterized by that the spring frame (1) is made as a sheet metal part. [10] Radar device (10) according to one of the preceding claims, characterized by that the frame part (2) is made in one piece with the shielding surface (2a), preferably as a metal casting.

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