Radar sensor device for a motor vehicle, and motor vehicle having a radar sensor device

Abstract

The invention relates to a radar sensor device (3) for a motor vehicle, comprising a housing (4) and a radar sensor (5) for transmitting waves (XS) and receiving reflected waves (XR). The housing (4) comprises a radome region (6) and an absorber region (7). The absorber region (7) is less transmissive for waves (XR, XS) than the radome region (6). The absorber region (7) surrounds the radar sensor (5) in the peripheral direction and, with the radar sensor (5), divides an air-tight interior (8) of the housing (4) into a first interior region (9) and a second interior region (10). The first interior region (9) is delimited by the radar sensor (5), the absorber region (7) and the radome region (6) and is shielded from the environment (11) by the radome region (6). The second interior region (10) is delimited, on the side of the radar sensor (5) remote from the first interior region (9), by the radar sensor (5) and the absorber region (7) and by an additional housing region (12). The radar sensor (5) comprises at least one component (14, 15) which releases waste heat to the interior (8). The absorber region (7) has at least two passage regions (16, 17) for exchanging gaseous fluid between the interior regions (9, 10).

Description

[0001] Radar sensor device for a motor vehicle and motor vehicle with a radar sensor device

[0002] The invention relates to a radar sensor device for a motor vehicle, comprising a housing and a radar sensor arranged therein and directed towards the surroundings, in particular the area in front of the motor vehicle, for transmitting waves and for receiving reflected waves according to the type defined in more detail in the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle with such a radar sensor device.

[0003] Known radar systems and radar sensor devices include sensors with at least one chip responsible for signal transformation and compression. During operation, these chips emit a considerable amount of heat, which must be dissipated to ensure the sensors' functionality.

[0004] For cooling, radar sensors are exposed to an external airflow on the signal-emitting front side or a fan or fans on the back. Such an airflow increases heat exchange and thus improves the cooling of the radar sensor.

[0005] To reduce costs and weight, the components of radar sensor devices are housed in a common housing. However, it is difficult to cool radar sensor antennas in an environment shielded from the environment. Since a fan positioned in front of the front of a radar sensor, in the direction of radar transmission, interferes with the transmission of radar waves, no fan can be installed there to cool the radar sensor. This results in a hot air pocket forming in front of the radar sensor in such solutions, which severely impairs the performance of the radar sensor.

[0006] It is also known to shield radar sensors from a portion of the reflected radar waves around their perimeter using a so-called absorber region in a housing. Such an absorber region attenuates both transmitted and reflected waves, or radar waves, thereby preventing the radar sensor from detecting so-called ghost targets. Such absorbers also impair the heat exchange between a radar sensor and the environment and promote the formation of the hot air bubbles described above.

[0007] WO 2015 / 094538 A1 describes a structure and technique for decoupling an automotive radar sensor from a surrounding electrically conductive structure, such as a vehicle, on which the sensor is mounted. The sensor comprises a housing with a radome. An antenna circuit board is arranged in the housing. A wedge-shaped absorption element, provided on the surface of the antenna, absorbs high-frequency energy emitted by the antenna. The high-frequency energy is coupled directly from the antenna to elements outside the sensor.

[0008] An antenna device is known from EP 3 905 432 A1, which has a small thickness and good heat radiation efficiency. One antenna transmits a radio wave to a communication target, and another antenna receives a radio wave from the communication target. The antennas are arranged on a planar antenna adapter. The antenna adapter is provided with a plurality of through-holes, each of which penetrates a surface on which the antennas are arranged. One surface of the antenna adapter faces an outer surface of a mobile object. In addition, the antennas and the antenna adapter are covered by a radome. A skirt is attached to an outer peripheral edge of the antenna adapter. One end of the skirt is connected to the radome, and another end of the skirt is connected to the outer surface of the mobile object.A fan is arranged in a space hermetically enclosed by the radome, the skirt and the outer surface of the mobile object to generate an air flow that flows into a space surrounded by the radome and the surface of the antenna adapter in which the antenna is arranged.

[0009] The object of the present invention is to provide a radar sensor device for a motor vehicle and a motor vehicle with a radar sensor device, with which a desired function of a radar sensor can be ensured over the widest possible operating range. According to the invention, this object is achieved with a radar sensor device for a motor vehicle and with a motor vehicle with a radar sensor device having the features of patent claims 1 and 9, respectively.

[0010] The radar sensor device according to the invention for a motor vehicle comprises a housing and a radar sensor arranged therein. The radar sensor is directed toward the surroundings, in particular the area in front of the motor vehicle, and is designed to transmit waves and receive reflected waves.

[0011] The housing comprises a radome section and an absorber section. The absorber section is designed with lower wave permeability than the radome section to reduce the reception of reflected waves that impair the radar sensor's ability to detect objects.

[0012] Furthermore, the absorber region surrounds the radar sensor in the circumferential direction and, together with the radar sensor, separates an airtight interior of the housing into a first interior region and a second interior region. The first interior region is delimited by the radar sensor, the absorber region, and the radome region, and is shielded from the surroundings of the radar sensor device by the radome region. The second interior region is delimited, on the side of the radar sensor facing away from the first interior region, by the radar sensor and the absorber, as well as by a further housing region, and is preferably shielded from the motor vehicle. In addition, the radar sensor comprises at least one component that dissipates waste heat into the interior, which component can be, for example, a CMOS radar chip, an antenna of the radar sensor, or the like.

[0013] According to the invention, the absorber region is designed with at least two passage areas for the exchange of gaseous fluid between the interior regions, which represent flow paths for the fluid, each with defined flow cross-sections. This allows both the first interior region and the second interior region, which is arranged behind the radar sensor and the absorber region of the housing in the installed position of the radar sensor device, to be temperature-controlled to the desired extent. The radar sensor device according to the invention thus enables the desired shielding of the radar sensor against environmental influences such as moisture, dirt, and the like, and against reflected radar waves, which cause the detection of so-called ghost targets and hinder the interference-free detection of objects.Furthermore, the design of the radar sensor device according to the invention enables cooling in a structurally simple and space-saving manner, with which the functionality of the radar sensor can be ensured.

[0014] The radar sensor can, for example, be operated in a frequency range of 76 GHz to 77 GHz and be a so-called short-range radar with a detection range of between 100 m and 150 m or a so-called full-range radar with a detection range of approximately 300 m to 400 m.

[0015] Depending on the particular application, the radar sensor device according to the present invention can also be designed with other radar sensors that operate in different frequency ranges and that are intended to detect objects within further detection ranges.

[0016] In order to be able to provide the desired cooling capacity for the radar sensor, it is possible to provide at least one fan or ventilator in the second interior area, by means of which a convection flow can be generated between the two interior areas.

[0017] It can be provided that the fan is arranged in the second interior region such that gaseous fluid flows from the second interior region into the first interior region via a first passage region and from the first interior region through at least one second passage region into the second interior region when the fan generates the convection flow during operation. This has the effect, in a structurally simple manner, that gaseous fluid, which has a lower temperature than the gaseous fluid in the first interior region during operation of the radar sensor device, is introduced from the second interior region into the first interior region, and that the warmer gaseous fluid is introduced from the first interior region into the second interior region.Thus, heat energy can be transferred from the first interior area to the second interior area with little effort and can be released there into the environment of the radar sensor device.

[0018] The absorber can have an absorber sub-region and at least two further absorber sub-regions. It is possible for the further absorber regions to each consist of an open-cell foam and, with respect to the radar sensor, to be enclosed by the absorber sub-region at least on the outside. The flow cross-sections of the cells of the further absorber sub-regions then form the flow cross-sections of the passage regions and are designed such that a fluid flow required to regulate the operating temperature in the first interior region can be guided through the first passage region from the second interior region toward the first interior region and through the second passage region from the first interior region into the second interior region.

[0019] In other words, in such an embodiment of the radar sensor device according to the invention, the flow cross-sections of the passage areas are each formed by a plurality of flow cross-sections, each of which corresponds to the open cross-sections of the cells of the open-cell foam of the additional absorber sub-areas. Thus, on the one hand, desired air flows through the additional absorber sub-areas are enabled. On the other hand, the additional absorber sub-areas enable a desired attenuation or absorption or capture of radar waves transmitted by the radar sensor, as well as radar waves reflected by external objects, in a cost-effective and space-efficient manner.

[0020] In a further embodiment of the radar sensor device according to the invention, in which air can be guided through the passage areas for cooling and in which the detection of so-called ghost targets is avoided in a cost-effective manner, the additional absorber sub-areas are formed from expanded polypropylene. For the attenuation or absorption of radar waves, it is advantageous if the flow cross-sections of the additional absorber sub-areas are much smaller than the wavelengths of the transmitted and reflected waves.

[0021] Additionally, the absorber region may be formed from a closed foam, and the passage areas in the foam may be designed as conical channels. The diameters of the passage areas may taper from the first interior region toward the second interior region in such a way that, on the one hand, fluid can be guided through the passage areas between the two interior regions, and, on the other hand, transmitted and reflected waves are captured in the passage areas.

[0022] With respect to the convection flow of the fluid from the second interior space and through the first passage area toward the first interior space, the fan can be arranged upstream of the first passage area and directly in front of a fluid inlet area into the first passage area. Gaseous fluid can then be introduced from the second interior space into the first interior space with high efficiency.

[0023] Furthermore, the present invention relates to a motor vehicle which is equipped with a radar sensor device according to the invention as described in more detail above.

[0024] Further embodiments of the invention are the subject of the dependent claims. Exemplary embodiments of the invention are illustrated in the drawings and explained in more detail below.

[0025] It shows:

[0026] Fig. 1 is a schematic side view of a vehicle with a radar sensor device;

[0027] Fig. 2 is a highly simplified partial view of a first embodiment of the radar sensor device of the vehicle according to Fig. 1; and

[0028] Fig. 3 is a highly simplified partial view of a second embodiment of the radar sensor device of the vehicle according to Fig. 1. Fig. 1 shows a side view of a motor vehicle 1, which is equipped with a radar sensor device 3 in the region of a vehicle front 2. Fig. 2 and Fig.

[0029] 3 each show highly simplified partial sectional views of various embodiments of the radar sensor device 3, which essentially differ from one another only in certain areas. For the sake of clarity, the following description of Fig. 2 and Fig. 3 uses the same reference numerals for structurally and functionally identical components.

[0030] The radar sensor device 3 according to Fig. 2 comprises a housing 4 and a radar sensor 5 arranged therein. The radar sensor device 3 is arranged in the region of the vehicle front 2. The radar sensor 5 is directed toward the area in front of the motor vehicle 1 and, during operation, transmits electromagnetic or high-frequency radar waves XS in the forward direction of travel X and receives electromagnetic or high-frequency waves or radar waves XR reflected by external objects.

[0031] Toward the front of the vehicle 2, the housing 4 is formed with a radome region 6. The housing 4 also includes an absorber region 7, which surrounds the radar sensor 5 on its periphery and has a low permeability for waves XS transmitted by the radar sensor 5 and also for reflected waves XR. This ensures in a simple manner that the radar sensor 5 does not detect so-called ghost targets. In other words, the absorber region 7 ensures that the radar sensor 5 receives only the reflected waves XR necessary to fulfill its function.

[0032] In addition, the absorber region 7 with the radar sensor 5 separates an airtight interior 8 of the housing 4 into a first interior region 9 and a second interior region 10. The first interior region 9 is delimited by the radar sensor 5, the absorber region 9 and the radome region 6 and is shielded from the surroundings 11 of the motor vehicle 1. The second interior region 10 is delimited, on the side of the radar sensor 5 facing away from the first interior region 9, by the absorber region 7, the wheel sensor and by a further housing region 12. The further housing region 12 can be a further element of the housing 4, a body element or part of the front bumper 13 of the vehicle 1. The second interior region 10 is shielded from the vehicle interior of the motor vehicle 1 and also from the surroundings 11 or the environment of the motor vehicle 1 by the further housing region 12.

[0033] The absorber region 7 extends in the forward direction of travel X from a front side 5A of the radar sensor 5 into the first interior region 9 and delimits a funnel-shaped cavity 9A within the first interior region 9. The radar sensor 5 can be constructed in a manner known per se and, in addition to an antenna 14, can also comprise a chip 15, both of which emit waste heat to the interior 8 during operation of the radar sensor device 3. In order to prevent an undesirably high increase in the temperature of the gaseous fluid present in the first interior region 9 or the air in the first interior region 9 due to the emitted waste heat during operation of the radar sensor device 3, the absorber region 7 is designed with two passage regions 16, 17, through which an exchange of air between the two interior regions 9 and 10 is possible.

[0034] In the first embodiment of the radar sensor device 3 according to Fig. 2, the absorber region 7 consists of an absorber sub-region 7A and two further absorber regions 7B, 7C. The absorber sub-region 7A encompasses the further absorber sub-regions 7B, 7C circumferentially, terminates with the radome region 6, and forms part of an outer side of the housing 4. In further embodiments of the radar sensor device 3 that deviate from this and are not shown in detail in the drawing, the absorber sub-region 7A can also be encompassed on the outside by a further housing outer wall and shielded from the surroundings 11. The further absorber sub-regions 7B, 7C each consist of an open-cell foam, preferably expanded polypropylene. The sums of the individual open flow cross-sections of the cells of the further absorber sub-regions 7B, 7C each form the flow cross-sections of the passage regions 16, 17.The open flow cross-sections of the cells of the additional absorber sub-regions 7B, 7C are designed and dimensioned such that an air flow required to regulate the operating temperature in the second interior region 10 can be guided through the passage regions 16, 17. The flow cross-sections of the cells of the additional absorber sub-regions 7B, 7C are much smaller than the wavelengths of the waves XS transmitted by the radar sensor 5 and also smaller than the wavelengths of the waves XR reflected back to the radar sensor 5 by external objects. In addition, the absorber sub-region 7A is formed from a closed foam.

[0035] This enables, on the one hand, an air exchange between the interior regions 9 and 10 through the passage areas 16, 17 of the further absorber sub-regions 7B, 7C to regulate the operating temperature of the radar sensor device 3 in the first interior region 9. On the other hand, reflected waves XR, which cause the detection of so-called ghost targets in the region of the radar sensor 5, are captured in the further absorber sub-regions 7B, 7C and in the absorber sub-region 7A.

[0036] In addition, a fan or a ventilator 18 is arranged in the second interior region 10, which, during operation, generates a convection flow 19A to 19D between the interior regions 9 and 10. The fan 18 is arranged in the second interior region 10 with respect to the convection flow 19A of the fluid through the passage region 16 from the second interior region 10 of the further absorber sub-region 7B in the direction of the first interior region 9 upstream of the passage region 16 and directly in front of an inlet region 16E of the fluid into the passage region 16.

[0037] The absorber region 7 of the second embodiment of the radar sensor device 3 according to Fig. 3 is made entirely of a closed foam. The passage regions 16, 17 are designed as conical channels. The diameters of the passage regions 16, 17 taper from the first interior region 9 toward the second interior region 10 in such a way that, on the one hand, air can be guided through the passage regions 16, 17 between the interior regions 9 and 10, and, on the other hand, reflected waves XR are captured in the passage regions 16, 17. In the radar sensor device 3 according to Fig. 3, the fan 18 is also arranged in front of the inlet region 16E of the passage region 16, through which air is guided from the second interior region 10 into the first interior region 9.

[0038] By means of the radar sensor device 3 according to Fig. 2 or Fig. 3, depending on the design of the radar sensor 5, a parking aid, an adaptive cruise control, an autonomous emergency braking function, a collision mitigation function and / or a stop-and-go operation can be represented.

[0039] Furthermore, it is also possible to position the radar sensor device 3 at a different location on the motor vehicle 1 in order to be able to provide, for example, one of the following driver assistance systems: parking aid, lane change assistant, lane keeping assistant, detection of an object in the blind spot, side impact warning, detection of cross traffic passing the rear of the vehicle, reversing aid, rear collision warning.

[0040] List of reference symbols

[0041] 1 motor vehicle

[0042] 2 Front of vehicle

[0043] 3 Radar sensor device

[0044] 4 housings

[0045] 5 Radar sensor

[0046] 5A Front of the radar sensor

[0047] 6 Radome area

[0048] 7 Absorber area

[0049] 7A Absorber section

[0050] 7B, 7C further absorber section

[0051] 8 Interior

[0052] 9 first interior area

[0053] 9A funnel-shaped cavity

[0054] 10 second interior area

[0055] 11 Environment of the motor vehicle

[0056] 12 additional housing areas

[0057] 13 Bumper of the motor vehicle

[0058] 14 Radar sensor antenna

[0059] 15 Radar sensor chip

[0060] 16 passband

[0061] 16E Entrance area of ​​the passband 16

[0062] 17 Passband

[0063] 18 Fan or ventilator

[0064] 19A to 19D Convection current

[0065] X Forward direction

[0066] XR reflected radar wave

[0067] XS transmitted radar wave

Claims

Patent claims 1. Radar sensor device (3) for a motor vehicle (1), comprising a housing (4) and a radar sensor (5) arranged therein and directed towards the surroundings (11), in particular the area in front of the motor vehicle (1), for transmitting waves (XS) and for receiving reflected waves (XR), wherein the housing (4) comprises a radome region (6) and an absorber region (7), wherein the absorber region (7) is designed with a lower permeability for waves (XS, XR) than the radome region (6) in order to reduce the reception of reflected waves (XR) that impair the function of the radar sensor (5), wherein the absorber region (7) surrounds the radar sensor (6) in the circumferential direction and, together with the radar sensor (5), separates an airtight interior space (8) of the housing (4) into a first interior space (9) and a second interior space (10), wherein the first interior space (9) is separated from the radar sensor (5),the absorber region (7) and the radome region (6) and is shielded from the surroundings (11), wherein the second interior region (10) is delimited on the side of the radar sensor (5) facing away from the first interior region (9) by the radar sensor (5), the absorber region (7) and a further housing region (12), and wherein the radar sensor (5) comprises at least one component (14, 15) dissipating waste heat into the interior space (8), characterized in that the absorber region is designed with at least two passage regions for the exchange of gaseous fluid between the interior regions.

2. Radar sensor device according to claim 1, characterized in that at least one fan (18) is arranged in the second interior region (10), by means of which a convection flow can be generated between the two interior regions (9, 10).

3. Radar sensor device according to claim 2, characterized in that the fan (18) is arranged in the second interior region (10) in such a way that fluid is conveyed via a first passage region (16) from the second interior region (10) into the first interior region (9) and fluid flows through at least one second passage region (17) from the first interior region (9) into the second interior region (10) when the fan (18) generates the convection flow during operation.

4. Radar sensor device according to one of claims 1 to 3, characterized in that the absorber region (7) has an absorber sub-region (7A) and at least two further absorber sub-regions (7B, 7C), wherein the further absorber sub-regions (7B, 7C) are formed from an open-cell foam and are enclosed by the absorber sub-region (7A) at least on the outside with respect to the radar sensor (5), wherein flow cross-sections of the cells of the further absorber sub-regions (7B, 7C) each form the flow cross-sections of the passage regions (16, 17) and are designed such that a fluid flow required for controlling the operating temperature in the first interior region (9) can be guided through the first passage region (16) from the second interior region (10) in the direction of the first interior region (9) and from the first interior region (9) through the second passage region (17) into the second interior region (10).

5. Radar sensor device according to claim 4, characterized in that the flow cross sections of the cells of the further absorber sub-regions (7B, 7C) are much smaller than the wavelengths of the transmitted waves (XS) and the reflected waves (XR).

6. Radar sensor device according to one of claims 1 to 3, characterized in that the absorber region (7) is formed at least partially from a closed foam and the passage regions (16, 17) in the foam are designed as conical channels, the diameter of which tapers from the first interior region (9) towards the second interior region (10) in such a way that, on the one hand, fluid can be guided through the passage regions (16, 17) between the interior regions (9, 10) and, on the other hand, reflected waves (XR) are captured in the passage regions (16, 17).

7. Radar sensor device according to one of claims 4 to 6, characterized in that the fan (18) with respect to the convection flow of the fluid consists of the second interior region (10) through the first passage region (16) of the further absorber sub-region (7B) in the direction of the first interior region (9) in the second interior region (10) upstream of the first passage region (16) and directly in front of an inlet region (16E) of the fluid into the first passage region (16).

8. Radar sensor device according to one of claims 1 to 7, characterized in that the absorber region (7), the absorber sub-region (7A) and / or the further absorber sub-regions (7B, 7C) is or are formed with expanded polypropylene.

9. Motor vehicle (1) comprising a radar sensor device (3) according to one of claims 1 to 8.

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