Radar sensor device for a motor vehicle and motor vehicle with a radar sensor device

Abstract

Radar sensor device (3) for a motor vehicle (1), comprising a housing (4) and a radar sensor (5) arranged therein and directed towards the environment (11), in particular the area in front of the motor vehicle (1) for transmitting waves (XS) and receiving reflected waves (XR), wherein the housing (4) comprises a radome area (6) and an absorber area (7), wherein the absorber area (7) is designed with a lower transmittance for waves (XS, XR) than the radome area (6) in order to reduce the reception of reflected waves (XR) which impair the function of the radar sensor (5), wherein the absorber area (7) surrounds the radar sensor (5) circumferentially 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 bounded by the radar sensor (5), the absorber area (7) and the radome area (6) and is shielded from the environment (11), wherein the second interior area (10) is bounded on the side of the radar sensor (5) facing away from the first interior area (9) by the radar sensor (5), the absorber area (7) and by a further housing area (12), and wherein the radar sensor (5) comprises at least one component (14, 15) that dissipates waste heat to the interior (8) characterized by the fact that the absorber area (7) is designed with at least two passage areas (16 ,17) for the exchange of gaseous fluid between the interior areas (9, 10).

Description

[0001] 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 environment, in particular the area in front of the motor vehicle, for transmitting waves and receiving reflected waves according to the type defined in more detail in the preamble of claim 1. The invention further relates to a motor vehicle with such a radar sensor device.

[0002] Known radar systems and radar sensor devices include sensors with at least one chip responsible for signal transformation and compression. During operation, these chips generate a considerable amount of heat that must be dissipated to ensure the sensors function correctly.

[0003] To cool radar sensors, external airflow is applied to the signal-emitting front surface, or a fan is used on the back. Such airflow increases heat exchange and thus improves the cooling of the radar sensor.

[0004] To reduce costs and weight, the components of radar sensor devices are housed in a common enclosure. However, cooling radar sensor antennas in an environment shielded from the surroundings is difficult. Since a fan positioned in front of the radar sensor, facing the direction of radar wave transmission, interferes with the transmission of radar waves, a fan cannot be used for cooling the radar sensor in this location. This results in a hot air pocket forming in front of the radar sensor in such solutions, which significantly impairs its performance.

[0005] Furthermore, it is known to shield radar sensors circumferentially from a portion of the reflected radar waves by means of a so-called absorber area within the housing. Such an absorber area attenuates both transmitted and reflected waves, or radar waves, thereby preventing the radar sensor from detecting so-called ghost targets. These absorbers also impair the heat exchange between a radar sensor and its environment and promote the formation of the hot air bubbles described above.

[0006] WO 2015 / 094538 A1 describes a structure and a 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 has a housing with a radome. An antenna circuit board is arranged within 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 then directly coupled from the antenna to elements outside the sensor.

[0007] An antenna device is known from EP 3 905 432 A1, which has a small thickness and good heat dissipation 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 has several through-holes, each penetrating a surface on which the antennas are arranged. One surface of the antenna adapter faces an outer surface of a mobile object. Additionally, the antennas and the antenna adapter are covered by a radome. A skirt is attached to an outer circumferential 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 blower is arranged in a space hermetically enclosed by the radome, the skirt and the outer surface of the mobile object to generate an airflow that flows into a space surrounded by the radome and the surface of the antenna adapter, in which the antenna is located.

[0008] The EP 3 514 888 is a device with a removable radar sensor capable of emitting a radio wave.

[0009] Furthermore, US 5 955 752 A describes a semiconductor module with a substrate, an antenna element formed on the substrate, and a semiconductor circuit.

[0010] 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 largest possible operating range.

[0011] According to the invention, this problem is solved with a radar sensor device for a motor vehicle and with a motor vehicle with a radar sensor device having the features of claim 1 or 9 respectively.

[0012] 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 towards the surroundings, in particular the area in front of the motor vehicle, and is designed to transmit waves and receive reflected waves.

[0013] The housing comprises a radome area and an absorber area. The absorber area has a lower wave transmission than the radome area in order to reduce the reception of reflected waves that would interfere with the radar sensor's detection of objects.

[0014] Furthermore, the absorber surrounds the radar sensor circumferentially and, together with the radar sensor, divides an airtight interior of the housing into a first interior space and a second interior space. The first interior space is bounded by the radar sensor, the absorber, and the radome area and is shielded from the surroundings of the radar sensor device by the radome area. The second interior space is bounded on the side of the radar sensor facing away from the first interior space by the radar sensor, the absorber, and another housing area, and is preferably shielded from the vehicle. Additionally, the radar sensor includes at least one component that dissipates heat into the interior space, which may be, for example, a CMOS radar chip, an antenna of the radar sensor, or the like.

[0015] According to the invention, the absorber section is designed with at least two passages for the exchange of gaseous fluid between the interior areas, which represent flow paths for the fluid with defined flow cross-sections. This allows both the first interior area and the second interior area, which in the installed position of the radar sensor device is arranged behind the radar sensor and the absorber section of the housing, to be temperature-controlled to the desired extent.

[0016] 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, thereby ensuring the functionality of the radar sensor.

[0017] 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 100 m to 150 m or a so-called full-range radar with a detection range of about 300 m to 400 m.

[0018] Depending on the specific application, the radar sensor device according to the present invention can also be equipped with other radar sensors that operate in different frequency ranges and are intended for detecting objects within further detection ranges.

[0019] In order to provide sufficient 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 between the two interior areas can be generated.

[0020] It can be provided that the fan is arranged in the second interior space such that gaseous fluid flows from the second interior space into the first interior space via a first passage area and from the first interior space into the second interior space via at least a second passage area when the fan generates the convection flow during operation. This achieves, in a structurally simple manner, that gaseous fluid, which has a lower temperature than the gaseous fluid in the first interior space during operation of the radar sensor device, is introduced from the second interior space into the first interior space, and that the warmer gaseous fluid is introduced from the first interior space into the second interior space.Thus, heat energy can be transferred from the first interior area to the second interior area with minimal effort and can be released there to the environment of the radar sensor device.

[0021] The absorber can have one absorber section and at least two further absorber sections. These further absorber sections may each consist of an open-cell foam and be enclosed, at least externally, by the absorber section with respect to the radar sensor. The flow cross-sections of the cells of the further absorber sections then form the flow cross-sections of the passage areas and are designed to allow a fluid flow, required for maintaining the operating temperature in the first interior space, to flow through the first passage area from the second interior space towards the first interior space and through the second passage area from the first interior space into the second interior space.

[0022] 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 corresponding to the open cross-sections of the cells of the open-cell foam of the further absorber sections. Thus, on the one hand, desired airflows are enabled through the further absorber sections. On the other hand, the further absorber sections enable the desired attenuation or absorption or capture of radar waves emitted by the radar sensor, as well as radar waves reflected by external objects, in a cost-effective and space-saving manner.

[0023] 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 further absorber sub-areas are formed with expanded polypropylene.

[0024] For the attenuation or absorption of radar waves, it is advantageous if the flow cross-sections of the further absorber sub-areas are much smaller than the wavelengths of the transmitted waves and the reflected waves.

[0025] Additionally, the absorber area can be formed from a closed foam, with the passages in the foam designed as cone-shaped channels. The diameters of the passages can taper from the first interior space towards the second, allowing fluid to flow between the two spaces and trapping both transmitted and reflected waves within the passages.

[0026] The fan can be positioned upstream of the first passage area and directly in front of the fluid inlet to the first passage area, relative to the convection flow of the fluid from the second interior chamber and through the first passage area. This allows gaseous fluid to be introduced from the second interior chamber into the first interior chamber with high efficiency.

[0027] Furthermore, the present invention relates to a motor vehicle equipped with a radar sensor device as described above in more detail.

[0028] Further embodiments of the invention are the subject of the dependent claims. Exemplary embodiments of the invention are shown in the drawing and are explained in more detail below.

[0029] It shows: Fig. 1 a schematic side view of a vehicle with a radar sensor device; Fig. 2 a highly simplified partial representation of a first embodiment of the radar sensor device of the vehicle according to Fig. 1; and Fig. 3 a highly simplified partial representation of a second embodiment of the vehicle's radar sensor device according to Fig. 1.

[0030] Fig. Figure 1 shows a side view of a motor vehicle 1 which is equipped with a radar sensor device 3 in the area of ​​a vehicle front 2. Fig. 2 and Fig. Figure 3 shows highly simplified partial sectional views of various embodiments of the radar sensor device 3, which differ essentially only in certain areas. For the sake of clarity, the following description will refer to Fig. 2 and Fig. 3. The same reference symbols are used for components that are identical in construction and function.

[0031] 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 located in the area of ​​the front of the vehicle 2. The radar sensor 5 is directed towards the area in front of the vehicle 1 and, during operation, transmits electromagnetic or high-frequency radar waves XS in the forward direction X and receives electromagnetic or high-frequency waves or radar waves XR reflected from external objects.

[0032] Towards the front of the vehicle 2, the housing 4 is designed with a radome area 6. The housing 4 also includes an absorber area 7, which surrounds the radar sensor 5 and has low transmittance for both waves XS emitted by the radar sensor 5 and reflected waves XR. This ensures that the radar sensor 5 does not detect so-called ghost targets. In other words, the absorber area 7 is designed to allow the radar sensor 5 to receive only the reflected waves XR necessary for it to function.

[0033] Additionally, the absorber section 7 with the radar sensor 5 separates an airtight interior 8 of the housing 4 into a first interior space 9 and a second interior space 10. The first interior space 9 is bounded by the radar sensor 5, the absorber section 9, and the radome section 6 and is shielded from the environment 11 of the vehicle 1. The second interior space 10 is bounded on the side of the radar sensor 5 facing away from the first interior space 9 by the absorber section 7, the radar sensor 5, and another housing section 12. The other housing section 12 can be another element of the housing 4, a body panel, or part of the front bumper 13 of the vehicle 1. The second interior space 10 is shielded from the interior of the vehicle 1 and also from the environment 11 or the surroundings of the vehicle 1 by the other housing section 12.

[0034] The absorber area 7 extends in the forward direction X from a front face 5A of the radar sensor 5 into the first interior space 9 and defines a funnel-shaped cavity 9A within the first interior space 9. The radar sensor 5 can be constructed in a manner known per se and may include an antenna 14 and a chip 15, both of which release waste heat into the interior space 8 during operation of the radar sensor device 3. To prevent an undesirably high temperature increase of the gaseous fluid or air present in the first interior space 9 due to the released waste heat during operation of the radar sensor device 3, the absorber area 7 is designed with two passage areas 16, 17 through which air exchange between the two interior spaces 9 and 10 is possible.

[0035] In the first embodiment of the radar sensor device 3 according to Fig. 2. The absorber area 7 consists of an absorber sub-area 7A and two further absorber areas 7B and 7C. The absorber sub-area 7A encompasses the further absorber sub-areas 7B and 7C circumferentially, terminates with the radome area 6, and forms part of an outer surface of the housing 4. In further embodiments of the radar sensor device 3 that differ from this and are not shown in detail in the drawing, the absorber sub-area 7A can also be enclosed on the outside by another outer housing wall and shielded from the environment 11. The further absorber sub-areas 7B and 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-areas 7B, 7C each form the flow cross-sections of the passage areas 16, 17. The open flow cross-sections of the cells of the further absorber sub-areas 7B, 7C are designed as follows:dimensioned so that an airflow required to regulate the operating temperature in the second interior area 10 can be guided through the passage areas 16, 17.

[0036] The flow cross-sections of the cells in the further absorber sub-areas 7B and 7C are much smaller than the wavelengths of the XS waves emitted by the radar sensor 5, and also smaller than the wavelengths of the XR waves reflected back to the radar sensor 5 by external objects. Additionally, absorber sub-area 7A is made of a closed foam.

[0037] This allows, on the one hand, air exchange between interior areas 9 and 10 through the passage areas 16, 17 of the further absorber sub-areas 7B, 7C to regulate the operating temperature of the radar sensor device 3 in the first interior area 9. On the other hand, reflected waves XR, which in the area of ​​the radar sensor 5 cause the detection of so-called ghost targets, are trapped in the further absorber sub-areas 7B, 7C and in absorber sub-area 7A.

[0038] Additionally, a fan 18 is arranged in the second interior space 10, which generates a convection flow 19A to 19D between interior spaces 9 and 10 during operation. The fan 18 is positioned in the second interior space 10, with respect to the convection flow 19A of the fluid through the passage 16 from the second interior space 10 of the further absorber section 7B towards the first interior space 9, upstream of the passage 16 and directly in front of an inlet 16E of the fluid into the passage 16.

[0039] The absorber area 7 of the second embodiment of the radar sensor device 3 according to Fig. 3 is made entirely of closed-cell foam. The passage areas 16, 17 are designed as conical channels. The diameters of the passage areas 16, 17 taper from the first interior area 9 towards the second interior area 10 such that, on the one hand, air can be guided through the passage areas 16, 17 between the interior areas 9 and 10, and on the other hand, reflected waves XR are trapped in the passage areas 16, 17.

[0040] The fan 18 is also used in the radar sensor device 3 according to Fig. 3 arranged in front of the entrance area 16E of the passage area 16, through which air from the second interior area 10 is guided into the first interior area 9.

[0041] By means of the radar sensor device 3 according to Fig. 2 or according to Fig.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.

[0042] Furthermore, it is also possible to position the radar sensor device 3 at another location on the motor vehicle 1 in order to provide, for example, one of the following driver assistance systems: parking aid, lane change assist, lane keeping assist, blind spot detection, side impact warning, cross traffic detection, reversing aid, rear collision warning. Reference symbol list 1 motor vehicle 2 Vehicle front 3 Radar sensor device 4 cases 5 radar sensor 5A Front of the radar sensor 6 Radome area 7 Absorber area 7A Absorber section 7B, 7C further absorber section 8 Interior 9 first interior area 9A funnel-shaped cavity 10 second interior area 11. Environment of the motor vehicle 12 additional housing areas 13. Bumper of the motor vehicle 14 Antenna of the radar sensor 15. Radar sensor chip 16 Passage area 16E Entrance area of ​​passage area 16 17 Passage area 18 fan or ventilator 19A to 19D Convection current X Forward direction XR reflected radar wave XS transmitted radar wave

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 environment (11), in particular the area in front of the motor vehicle (1) for transmitting waves (XS) and receiving reflected waves (XR), wherein the housing (4) comprises a radome area (6) and an absorber area (7), wherein the absorber area (7) is designed with a lower transmittance for waves (XS, XR) than the radome area (6) in order to reduce the reception of reflected waves (XR) which impair the function of the radar sensor (5), wherein the absorber area (7) surrounds the radar sensor (5) circumferentially 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 bounded by the radar sensor (5), the absorber area (7) and the radome area (6) and is shielded from the environment (11), wherein the second interior area (10) is bounded on the side of the radar sensor (5) facing away from the first interior area (9) by the radar sensor (5), the absorber area (7) and by a further housing area (12), and wherein the radar sensor (5) comprises at least one component (14, 15) that dissipates waste heat to the interior (8) characterized by , that the absorber area (7) is designed with at least two passage areas (16 ,17) for the exchange of gaseous fluid between the interior areas (9, 10). [2] Radar sensor device according to claim 1, characterized by , that in the second interior space (10) at least one fan (18) is arranged, by means of which a convection flow between the two interior spaces (9, 10) can be generated. [3] Radar sensor device according to claim 2, characterized by, that the fan (18) is arranged in the second interior space (10) such that fluid flows from the second interior space (10) into the first interior space (9) via a first passage area (16) and fluid flows from the first interior space (9) into the second interior space (10) via at least a second passage area (17) when the fan (18) generates the convection flow during operation. [4] Radar sensor device according to any one of claims 1 to 3, characterized by, that the absorber area (7) has an absorber sub-area (7A) and at least two further absorber sub-areas (7B, 7C), wherein the further absorber sub-areas (7B, 7C) are formed from an open-cell foam and are encompassed at least on the outside of the absorber sub-area (7A) with respect to the radar sensor (5), wherein the flow cross-sections of the cells of the further absorber sub-areas (7B, 7C) each form the flow cross-sections of the passage areas (16, 17) and are designed to allow a fluid flow required for temperature control of the operating temperature in the first interior area (9) to flow through the first passage area (16) from the second interior area (10) towards the first interior area (9) and from the first interior area (9) through the second passage area (17) into the second interior area (10). [5] Radar sensor device according to claim 4, characterized by, that the flow cross-sections of the cells of the further absorber sub-areas (7B, 7C) are much smaller than the wavelengths of the transmitted waves (XS) and the reflected waves (XR). [6] Radar sensor device according to any one of claims 1 to 3, characterized by , that the absorber area (7) is at least partially formed from a closed foam and the passage areas (16, 17) in the foam are formed as conical channels whose diameters taper from the first interior area (9) towards the second interior area (10) in such a way that, on the one hand, fluid can be guided through the passage areas (16, 17) between the interior areas (9, 10) and, on the other hand, reflected waves (XR) are trapped in the passage areas (16, 17). [7] Radar sensor device according to any one of claims 4 to 6, characterized by, that the fan (18) is arranged in relation to the convection flow of the fluid from the second interior area (10) through the first passage area (16) of the further absorber section (7B) in the direction of the first interior area (9) in the second interior area (10) upstream of the first passage area (16) and directly in front of an inlet area (16E) of the fluid into the first passage area (16). [8] Radar sensor device according to any one of claims 1 to 7, characterized by , that the absorber area (7), the absorber sub-area (7A) and / or the further absorber sub-areas (7B, 7C) are formed with expanded polypropylene. [9] Motor vehicle (1) comprising a radar sensor device (3) according to any one of claims 1 to 8.

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