Radar device

Abstract

To obtain a radar device capable of preventing deterioration of directivity characteristics.SOLUTION: A radar device includes: a metal case having a first wall, a first support wall protruding from the first wall, and a first outer wall protruding from the first wall shorter than the first support wall and surrounding the first support wall with a gap therebetween; a substrate having a first surface supported by the first support wall, a second surface located opposite to the first surface, and an antenna provided on the second surface; and a cover made of a dielectric body, which has a second wall covering the second surface, a second support wall supporting the second surface and holding the substrate between the first support wall and the second support wall, a second outer wall surrounding the first support wall and the substrate, and a convex wall protruding from the second outer wall and housed in the gap and surrounding the first support wall.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a radar device. [Background technology]

[0002] The radar device includes, for example, a substrate on which an antenna is mounted, a case that supports the substrate, and a cover that covers the substrate. The substrate is held between the case and the cover. The antenna emits radio waves through the cover, which is made of a dielectric material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-008474 Summary of the Invention [Problem to be solved by the invention]

[0004] Radio waves are emitted from the antenna not only in the front but also to the sides. If the case is made of metal, radio waves emitted to the sides may be reflected by the case. If the power of the radio waves reflected by the case is high, ringing occurs, which reduces the directional characteristics of the radar device.

[0005] The present invention has been made in view of the above, and provides a radar device that can prevent degradation of directional characteristics. [Means for solving the problem]

[0006] The radar device of the present invention comprises: a case made of metal having a first wall, a first support wall protruding from the first wall, and a first outer wall protruding from the first wall to a shorter distance than the first support wall and surrounding the first support wall with a gap; a substrate having a first surface supported by the first support wall, a second surface located opposite the first surface, and an antenna provided on the second surface; a second wall covering the second surface, a second support wall supporting the second surface and holding the substrate between itself and the first support wall; a second outer wall surrounding the first support wall and the substrate; and a convex wall protruding from the second outer wall, housed in the gap, and surrounding the first support wall, the cover being made of a dielectric. [Effects of the Invention]

[0007] According to the radar device of the present invention, it is possible to prevent degradation of directivity characteristics. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a vehicle according to an embodiment. [Figure 2] FIG. 2 is a plan view showing the radar device of the embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the radar device of the embodiment taken along line F3-F3 in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing the radar device of the embodiment taken along line F4-F4 in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing the device main body of the embodiment taken along line F5-F5 in FIG. [Figure 6] FIG. 6 is a perspective view showing the substrate, the case, and the screws of the embodiment. [Figure 7] FIG. 7 is a perspective view showing the substrate and the radome of the embodiment. [Figure 8] FIG. 8 is an enlarged cross-sectional view showing a part of the radar device of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. Note that in this specification, components according to the embodiment and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. Furthermore, the components may also be described using expressions different from those in this specification.

[0010] Fig. 1 is a diagram schematically illustrating an example of the configuration of a vehicle 1 according to this embodiment. As shown in Fig. 1, the vehicle 1 according to this embodiment includes a vehicle body 11, a plurality of seats 12, and an occupant detection system 13. However, the vehicle 1 is not limited to this example.

[0011] As shown in the drawings, for convenience, the X-axis, Y-axis, and Z-axis are defined in this specification. The X-axis, Y-axis, and Z-axis are perpendicular to each other. The X-axis is set along the width of the vehicle 1. The Y-axis is set along the length of the vehicle 1. The Z-axis is set along the height of the vehicle 1.

[0012] Furthermore, in this specification, the X direction, Y direction, and Z direction are defined. The X direction is a direction along the X axis, and includes the +X direction (rightward) indicated by the X axis arrow and the −X direction (leftward) opposite the X axis arrow. The Y direction is a direction along the Y axis, and includes the +Y direction (forward) indicated by the Y axis arrow and the −Y direction (backward) opposite the Y axis arrow. The Z direction is a direction along the Z axis, and includes the +Z direction (upward) indicated by the Z axis arrow and the −Z direction (downward) opposite the Z axis arrow.

[0013] The plurality of seats 12 are arranged in a passenger compartment R of the vehicle body 11. An occupant detection system 13 can detect occupants present in the passenger compartment R. The occupant detection result by the occupant detection system 13 is used, for example, for a seat belt reminder. The seat belt reminder notifies the passenger compartment R of seat positions where occupants have been detected but the seat belts are not fastened, for example.

[0014] The occupant detection system 13 includes a radar device 21 and a control device 22. The radar device 21 may also be referred to as a sensor device or a radio wave sensor. The radar device 21 is not limited to being installed in the occupant detection system 13, and may be installed in other systems that detect objects.

[0015] The radar device 21 is provided, for example, on the ceiling 11a of the vehicle body 11. The ceiling 11a is provided at an end of the vehicle interior R in the +Z direction. The radar device 21 emits radio waves as transmission waves toward the vehicle interior R and receives reflected waves generated when the transmission waves are reflected by an object present in the vehicle interior R. The control device 22 is provided, for example, in the dashboard and is electrically connected to the radar device 21 via a network such as a CAN (Controller Area Network). The positions of the radar device 21 and the control device 22 are not limited to this example. Furthermore, the occupant detection system 13 may have multiple radar devices 21.

[0016] Fig. 2 is a plan view showing the radar device 21 of this embodiment. Fig. 3 is a cross-sectional view showing the radar device 21 of this embodiment taken along line F3-F3 in Fig. 2. Fig. 4 is a cross-sectional view showing the radar device 21 of this embodiment taken along line F4-F4 in Fig. 2. As shown in Fig. 3, the radar device 21 has a device main body 31 and a bracket 32.

[0017] Fig. 5 is a cross-sectional view showing the device body 31 of this embodiment taken along line F5-F5 in Fig. 2. As shown in Fig. 5, the device body 31 has a housing 35 and a board 36. The housing 35 houses the board 36. The housing 35 has a case 41, a radome 42, and a plurality of screws 43. The radome 42 is an example of a cover.

[0018] 6 is a perspective view showing the substrate 36, the case 41, and the screws 43 of this embodiment. The case 41 is made of metal. As shown in FIG. 6, the case 41 has a first wall 51, a first support wall 52, a first outer wall 53, and a plurality of guides 54.

[0019] The first wall 51 is formed in a substantially rectangular plate shape extending along the XY plane. Note that the shape of the first wall 51 is not limited to this example. As shown in Fig. 3, the case 41 further has heat dissipation fins 55 protruding from the first wall 51 in the +Z direction.

[0020] The first support wall 52 protrudes from the first wall 51 in approximately the −Z direction, inside the edge of the first wall 51. As shown in FIG. 6 , the first support wall 52 has a support portion 61 and a plurality of protrusions 62.

[0021] The support portion 61 is formed in a substantially rectangular frame shape. As shown in Fig. 3, a recess 65 that is open substantially in the -Z direction is provided inside the support portion 61. Note that the shape of the support portion 61 is not limited to this example.

[0022] The support portion 61 has a support surface 61a, an inner surface 61b, and an outer surface 61c. The support surface 61a is provided at the tip of the support portion 61 in the -Z direction. The support surface 61a is formed to be approximately flat and faces approximately in the -Z direction. The inner surface 61b faces the inside of the frame-shaped support portion 61. The inner surface 61b defines a recess 65. The outer surface 61c is located opposite the inner surface 61b.

[0023] 5, a plurality of screw holes 66 are provided in the support portion 61. The plurality of screw holes 66 open into the support surface 61a at positions spaced apart from one another. The support surface 61a may be wider near the screw holes 66 than other portions.

[0024] As shown in FIG. 6, the multiple protrusions 62 protrude from the outer surface 61c of the support portion 61 in a direction perpendicular to the Z axis. The direction perpendicular to the Z axis includes the X direction and the Y direction and may be referred to as the horizontal direction. The horizontal direction is an example of a direction along the second surface. Note that the horizontal direction may become non-horizontal, for example, as the vehicle 1 tilts. The multiple protrusions 62 are spaced apart from one another.

[0025] As shown in Figures 3 and 5, the frame-shaped support portion 61 has four walls 61F, 61B, 61R, and 61L. As shown in Figure 3, the walls 61F and 61B each extend linearly in approximately the X direction. The wall 61F is spaced apart from the wall 61B in the +Y direction. As shown in Figure 5, the walls 61R and 61L each extend linearly in approximately the Y direction. The wall 61R is spaced apart from the wall 61L in the +X direction.

[0026] 6, one protrusion 62 protrudes from the outer surface 61c of each of the walls 61F, 61B, 61R, and 61L. Note that the number of protrusions 62 protruding from the walls 61F, 61B, 61R, and 61L is not limited to this example.

[0027] The protruding portions 62 protruding from the walls 61F, 61B are shorter in length in the X direction than the walls 61F, 61B. The protruding portions 62 protruding from the walls 61R, 61L are shorter in length in the Y direction than the walls 61R, 61L.

[0028] The first outer wall 53 protrudes from the edge of the first wall 51 in approximately the -Z direction. Note that the first outer wall 53 may be spaced apart from the edge of the first wall 51. The first outer wall 53 is formed in a substantially rectangular frame shape and surrounds the first support wall 52 with a gap G therebetween. The gap G may also be referred to as a groove or a recess. Note that a notch may be provided in at least one of the first support wall 52 and the first outer wall 53.

[0029] The gap G is a groove that is provided between the first support wall 52 and the first outer wall 53 and that opens in approximately the -Z direction. Therefore, the gap G is formed in a frame shape that surrounds the first support wall 52. Note that the shape of the gap G is not limited to this example.

[0030] The first outer wall 53 has a tip 53a in the -Z direction. In the Z direction, the length of the first outer wall 53, which is the distance between the first wall 51 and the tip 53a, is approximately constant. Note that the tip 53a may have an uneven surface.

[0031] 3, in the Z direction, the distance between the first wall 51 and the tip 53a of the first outer wall 53 is shorter than the distance between the first wall 51 and the support surface 61a of the first support wall 52. In other words, the first outer wall 53 protrudes less from the first wall 51 than the first support wall 52.

[0032] 6, the multiple guides 54 protrude from the first support wall 52. In this embodiment, the multiple guides 54 protrude in approximately the −Z direction from the multiple protruding portions 62. Therefore, the multiple guides 54 are spaced apart from one another.

[0033] The multiple guides 54 include guides 54F, 54B, 54R, and 54L. Guide 54F is provided on a protruding portion 62 protruding from wall 61F. Guide 54B is provided on a protruding portion 62 protruding from wall 61B. Guide 54R is provided on a protruding portion 62 protruding from wall 61R. Guide 54L is provided on a protruding portion 62 protruding from wall 61L.

[0034] In the X direction, the length (width) of guide 54F is shorter than the length (width) of overhanging portion 62 that protrudes from wall 61F. In the X direction, the length of guide 54B is shorter than the length of overhanging portion 62 that protrudes from wall 61B.

[0035] In the Y direction, the length (width) of guide 54R is shorter than the length (width) of protruding portion 62 protruding from wall 61R. In the X direction, the length of guide 54L is shorter than the length of protruding portion 62 protruding from wall 61L.

[0036] 7 is a perspective view showing the substrate 36 and the radome 42 of this embodiment. The radome 42 is made of a dielectric material such as synthetic resin. As shown in FIGS. 3 and 7, the radome 42 has a second wall 71, a second support wall 72, a second outer wall 73, a convex wall 74, four protrusions 75, and two mounting portions 76.

[0037] 3, the second wall 71 is spaced apart in the −Z direction from the first wall 51 of the case 41. The second wall 71 is formed in the shape of a substantially rectangular plate extending along the XY plane. Note that the shape of the second wall 71 is not limited to this example.

[0038] The second support wall 72 is provided on the edge of the second wall 71. That is, the second support wall 72 surrounds the second wall 71. The second support wall 72 may be spaced apart from the edge of the second wall 71. The second support wall 72 at least partially protrudes from the second wall 71 in approximately the +Z direction. As shown in FIG. 5, the second support wall 72 has a support surface 72a.

[0039] The support surface 72a is provided at an end of the second support wall 72 in the +Z direction. The support surface 72a is formed to be approximately flat and faces approximately in the +Z direction. The support surface 72a of the second support wall 72 and the support surface 61a of the case 41 face each other with a gap between them. A plurality of through holes 81 are provided in the second support wall 72. The through holes 81 penetrate the second support wall 72 approximately in the Z direction and open to the support surface 72a.

[0040] The second outer wall 73 protrudes substantially in the +Z direction from the outer edge of the second support wall 72. Note that the second outer wall 73 may be spaced apart from the edge of the second support wall 72, or may protrude from the second wall 71.

[0041] The second outer wall 73 is formed in a substantially rectangular frame shape and surrounds the first support wall 52 of the case 41 with a gap in the horizontal direction. Furthermore, a tip 53a of the first outer wall 53 is formed so as to be outside the second outer wall 73 and the convex wall 74 with a space in the Y direction.

[0042] The convex wall 74 protrudes from the second outer wall 73 in approximately the +Z direction. The convex wall 74 is formed in a substantially rectangular frame shape. The convex wall 74 surrounds the first support wall 52 of the case 41 and is housed in the gap G. The convex wall 74 is spaced apart from the first wall 51, the first support wall 52, and the first outer wall 53 of the case 41. Note that the convex wall 74 may be in contact with at least one of the first wall 51, the first support wall 52, and the first outer wall 53.

[0043] As shown in Fig. 7, the four protrusions 75 protrude horizontally from the second outer wall 73. For example, two protrusions 75 protrude from the second outer wall 73 in approximately the +Y direction, and the other two protrusions 75 protrude from the second outer wall 73 in approximately the -Y direction. The four protrusions 75 are spaced apart from one another. However, the protrusions 75 are not limited to this example.

[0044] Each of the two mounting portions 76 has a base 85, a curved portion 86, and a claw 87. The base 85 protrudes horizontally from the second outer wall 73 longer than the protrusion 75. The curved portion 86 protrudes from the tip of the base 85 in approximately the +Z direction. That is, the mounting portions 76 are formed in a substantially L-shape. However, the mounting portions 76 are not limited to this example. The claw 87 protrudes from the curved portion 86.

[0045] The mounting portion 76 is located, for example, between two protrusions 75. In one mounting portion 76, the base 85 protrudes from the second outer wall 73 in approximately the +Y direction, and the claw 87 protrudes from the curved portion 86 in approximately the +Y direction. In the other mounting portion 76, the base 85 protrudes from the second outer wall 73 in approximately the -Y direction, and the claw 87 protrudes from the curved portion 86 in approximately the -Y direction.

[0046] 5, each of the multiple screws 43 has a screw shaft 91 and a screw head 92. The screw shaft 91 extends substantially in the Z direction and fits into the screw hole 66. The screw head 92 is provided at the end of the screw shaft 91 in the -Z direction.

[0047] The substrate 36 is, for example, a printed circuit board (PCB). However, the substrate 36 is not limited to this example. As shown in Fig. 3, the substrate 36 has a first surface 36a, a second surface 36b, a side surface 36c, and a plurality of antennas 36d.

[0048] The first surface 36a is a substantially rectangular plane and faces substantially in the +Z direction. The second surface 36b is located on the opposite side of the first surface 36a. The second surface 36b is a substantially rectangular plane and faces substantially in the -Z direction. Therefore, the horizontal direction is the direction along the second surface 36b. The side surface 36c is provided between the edge of the first surface 36a and the edge of the second surface 36b.

[0049] The first surface 36a faces the first wall 51 via the recess 65 and is supported by the first support wall 52. In this embodiment, the support surface 61a of the support portion 61 supports the first surface 36a on the inside of the edge of the first surface 36a.

[0050] The first support wall 52 supports the first surface 36a in the vicinity of the edge of the first surface 36a. Meanwhile, as shown in Fig. 6, the protruding portion 62 of the first support wall 52 protrudes horizontally beyond the edge of the first surface 36a and the side surface 36c.

[0051] 5, the second surface 36b faces the second wall 71 with a gap therebetween. In other words, the second wall 71 covers the second surface 36b. The second surface 36b is supported by the support surface 72a of the second support wall 72. This allows the first support wall 52 and the second support wall 72 to hold the substrate 36 between them.

[0052] As shown in Fig. 3, the side surface 36c faces the second outer wall 73 at a distance. The second outer wall 73 surrounds the substrate 36. As shown in Fig. 6, the side surface 36c is supported by at least one of the plurality of guides 54. In this way, the guide 54 restricts movement of the substrate 36 in the horizontal direction.

[0053] The plurality of antennas 36d are provided on the second surface 36b. The antennas 36d are patch antennas mounted on the substrate 36. However, the antennas 36d are not limited to this example and may be, for example, a conductor pattern provided on the substrate 36.

[0054] At least one of the multiple antennas 36d emits radio waves as transmission waves into the vehicle interior R. For example, the antenna 36d emits radio waves of a predetermined frequency. At least another of the multiple antennas 36d receives reflected waves generated when the transmission waves are reflected by an object present in the vehicle interior R.

[0055] The multiple antennas 36d are arranged, for example, linearly or in a grid pattern on the second surface 36b. That is, an array antenna including the multiple antennas 36d is provided on the substrate 36. However, the antenna 36d is not limited to this example.

[0056] The substrate 36 further includes various electronic components and electrical circuits. For example, a transmitter and a receiver are provided on the substrate 36. The transmitter and receiver include an antenna 36d, an oscillator circuit, an AD converter, an amplifier, and a filter circuit provided on the substrate 36. The transmitter emits a transmitted wave from the antenna 36d. The receiver generates an electrical signal indicating the intensity of the reflected wave received by the antenna 36d.

[0057] Furthermore, the board 36 has an ECU (Electronic Control Unit) of the radar device 21. The ECU is a microcontroller having a CPU (Central Processing Unit), memory, and various electronic components. The ECU performs processes related to, for example, control of the transmitter and receiver, and generation of data based on the reflected waves received by the receiver.

[0058] For example, an ECU is mounted on the first surface 36a of the substrate 36. The first support wall 52 surrounds the area of ​​the first surface 36a where components such as the ECU are mounted. The heat dissipation fins 55 cool the ECU.

[0059] 5, a plurality of through holes 101 are provided in the substrate 36. The through holes 101 penetrate the substrate 36 substantially in the Z direction and open to the first surface 36a and the second surface 36b. The screw holes 66 of the case 41, the through holes 81 of the radome 42, and the through holes 101 of the substrate 36 communicate with one another.

[0060] The screw shaft 91 of the screw 43 is inserted into the screw hole 66 through the through holes 81, 101. As a result, the screw 43 holds (fastens together) the substrate 36 and the second support wall 72 of the radome 42 between the screw head 92 and the first support wall 52. The screw head 92 is spaced farther from the first support wall 52 than the guide 54. In other words, the guide 54 protrudes from the first support wall 52 by a distance shorter than the screw 43. Furthermore, the length (width) of the guide 54 in the horizontal direction is shorter than the diameter of the screw shaft 91.

[0061] 2 is made of, for example, synthetic resin. The bracket 32 ​​has two adhesive portions 111, two engagement portions 112, and four holding portions 113. However, the bracket 32 ​​is not limited to this example.

[0062] Each of the two adhesive portions 111 is formed in a substantially rectangular plate shape extending along the XY plane. Note that the shape of the adhesive portions 111 is not limited to this example. The two adhesive portions 111 are spaced apart from each other in the X direction. In the X direction, the first outer wall 53 and the second outer wall 73 are located between the two adhesive portions 111. The adhesive portions 111 are attached to the ceiling 11a of the vehicle body 11 by, for example, an adhesive.

[0063] The two engaging portions 112 are located between the two adhesive portions 111 in the X direction. The two engaging portions 112 are spaced apart from each other in the Y direction. As shown in Fig. 3, a mounting hole 115 is provided in each of the two engaging portions 112.

[0064] The mounting holes 115 open toward the mounting portion 76 of the radome 42. The claws 87 of the mounting portion 76 fit into the mounting holes 115. As a result, the engaging portions 112 restrict the device body 31 from moving in the Z direction.

[0065] The claws 87 of the mounting portion 76 fit into the mounting holes 115 as the curved portion 86 elastically deforms. That is, the mounting portion 76 is attached to the engaging portion 112 of the bracket 32 ​​by snap-fitting. Note that the mounting portion 76 may also be attached to the bracket 32 ​​by other methods.

[0066] 2, each of the four holding portions 113 is provided between the adhesive portion 111 and the engagement portion 112. That is, the two holding portions 113 are spaced apart from each other in the Y direction. Each of the four holding portions 113 has a connection portion 117 and a spring portion 118.

[0067] The connecting portion 117 extends substantially in the X direction, and connects one of the two adhesive portions 111 to one of the two engaging portions 112. The spring portion 118 is a leaf spring, and protrudes from the connecting portion 117 toward the protrusion 75.

[0068] 4, the spring portion 118 elastically deforms and comes into contact with the protrusion 75. The spring portion 118 presses the protrusion 75 with its elastic force and holds the protrusion 75 with its frictional force. Therefore, the spring portions 118 of the two holding portions 113 spaced apart from each other in the Y direction hold the device main body 31. Note that the bracket 32 ​​may hold the protrusion 75 by other methods.

[0069] 1 is, for example, an ECU having a CPU, a memory, and various electronic components. The control device 22 is electrically connected to the ECU on the board 36. The control device 22 controls the ECU on the board 36 to emit a transmission wave to the antenna 36d, and obtains an electrical signal indicating the intensity of the reflected wave from the ECU on the board 36.

[0070] The control device 22 generates point cloud information based on the electrical signal indicating the intensity of the reflected wave. The point cloud information indicates one or more detection points representing the positions of occupants present in the vehicle interior R as a point cloud on a three-dimensional map corresponding to the vehicle interior R. The three-dimensional map corresponding to the vehicle interior R is, for example, a voxel map. The control device 22 determines the presence and position of occupants in the vehicle interior R based on the point cloud information.

[0071] Fig. 8 is an enlarged cross-sectional view of a portion of the radar device 21 of this embodiment. As shown in Fig. 8, the antenna 36d mainly emits radio waves at a beam angle (field of view) D. The beam angle D is, for example, a conical or elliptical conical range that spreads from the second surface 36b on which the antenna 36d is provided toward the substantially -Z direction in which the second surface 36b faces. The beam angle D may also be referred to as a radio wave irradiation area.

[0072] In this embodiment, the ratio of the area of ​​the second surface 36b (the size of the substrate 36) to the area of ​​the openings of the multiple antennas 36d is small. This allows the radar device 21 to be miniaturized, but weakens the reference potential of the substrate 36. If the reference potential of the substrate 36 is weak, the transmitter and receiver including the antenna 36d are more susceptible to electrical influence from the case 41 and the radome 42. For example, the directivity characteristics of the radar device 21 may become unstable. However, the radar device 21 of this embodiment can prevent the directivity characteristics from deteriorating and can increase the beam angle D, as described below.

[0073] The radio waves emitted from antenna 36d are distributed outside of directivity angle D. However, the power of the radio waves emitted from antenna 36d weakens as they deviate from directivity angle D. For example, the power of radio waves W1 emitted in a substantially horizontal direction is stronger than the power of radio waves W2 emitted in a direction closer to the +Z direction (diagonally upward) than radio waves W1.

[0074] The radio waves W1 are emitted from the antenna 36d toward an extension line L of the support surface 61a. However, the radio waves W1 are not emitted toward the support surface 61a, nor toward other parts of the case 41, such as the first outer wall 53. Therefore, the radio waves W1 are not reflected by the case 41.

[0075] The radio waves W2 are emitted from the antenna 36d toward the tip 53a of the first outer wall 53. As a result, the radio waves W2 are reflected by the first outer wall 53. However, the power of the radio waves W2 is weak. This makes it possible to suppress interference between the radio waves W2 reflected by the first outer wall 53 and radio waves within the beam angle required for detection. Therefore, the radar device 21 can prevent ringing from occurring in the radio waves W2.

[0076] In manufacturing the radar device 21, first, the substrate 36 is placed on the first support wall 52 of the case 41. At this time, a plurality of guides 54 can position the substrate 36. Next, the radome 42 covers the substrate 36 and is fitted into the case 41. Furthermore, the screws 43 are passed through the through holes 81 and 101 and fitted into the screw holes 66. In this way, the radar device 21 is assembled.

[0077] The guide 54 makes it easy to position the board 36. However, the screw 43 and the guide 54 protrude from the first support wall 52. For this reason, the antenna 36d may also emit radio waves toward the screw 43 and the guide 54.

[0078] Because the screws 43 and the guides 54 are made of metal, they may electrically affect the transmitter and receiver, including the antenna 36d. However, even if the guides 54 are omitted, the screws 43 are still provided to secure the substrate 36 and the radome 42 to the case 41. Therefore, the radar device 21 is designed to have a transmitter and receiver with sufficient performance even if affected by the screws 43. The guides 54 are smaller than the screws 43 in both the Z direction and the horizontal direction. Therefore, the guides 54 are less likely to affect the transmitter and receiver with sufficient performance due to the influence of the screws 43. In other words, the guides 54 facilitate the manufacture of the radar device 21 and can prevent the directional characteristics of the radar device 21 from deteriorating.

[0079] The radio waves emitted from the antenna 36d basically pass through the radome 42. However, some of the radio waves, such as millimeter waves, may flow through the dielectric interior of the radome 42. For example, the radio waves flow through the interior of the radome 42 to the protrusion 75 and are emitted from the protrusion 75. That is, some of the radio waves are also emitted from the protrusion 75, which is spaced apart from the antenna 36d in the Y direction. Therefore, the radar device 21 can expand the beam angle D as if a parasitic element were added. As described above, because the substrate 36 is small, the effect of the protrusion 75 on the beam angle D is easily noticeable. The protrusion 75 protrudes from the second outer wall 73 in a direction intended to expand the beam angle D. For example, the protrusion 75 extends along the major axis of the beam angle D of the elliptical cone.

[0080] As described above, the radar device 21 can prevent the directivity characteristics from being reduced by the first outer wall 53, can suppress the electrical influence from the guide 54, and can expand the beam angle D by utilizing the influence of the radome 42. By improving the directivity characteristics, the radar device 21 can improve the separation resolution for the occupant, who is the detection target.

[0081] The convex wall 74 is accommodated in the gap G between the first support wall 52 and the first outer wall 53. That is, the case 41 and the radome 42 are joined to each other by a fitting such as a spigot joint. Furthermore, the tip 53a of the first outer wall 53 is formed to be outside the second outer wall 73. Therefore, when the radar device 21 is installed facing the inside of the vehicle compartment R with the radio wave emission direction in the -Z direction, that is, when the radome 42 is disposed below the case 41, water generated by, for example, condensation does not flow directly into the inside of the housing 35. Even if water flows from the outside of the housing 35 into the gap between the tip 53a of the first outer wall 53 and the second outer wall 73, the convex wall 74 blocks the water. Therefore, the convex wall 74 can prevent water from entering the inside of the housing 35.

[0082] When the radome 42 is disposed above the case 41, water that has flowed into the gap between the tip 53a of the first outer wall 53 and the second outer wall 73 flows down the convex wall 74 to the bottom of the gap G. In this case, the first support wall 52 blocks the water and keeps it in the gap G. That is, the first support wall 52 can prevent water from entering the housing 35. That is, the radar device 21 of this embodiment can be made smaller and have improved drip-proof properties without degrading the directional characteristics.

[0083] The mounting portion 76 of the radome 42 is attached to the bracket 32. Furthermore, the bracket 32 ​​holds the protrusion 75 of the radome 42. Therefore, the protrusion 75 not only can increase the beam angle D, but also allows the device body 31 to be attached to the bracket 32 ​​more stably.

[0084] In the radar device 21 according to the embodiment described above, the case 41 has a first wall 51, a first support wall 52, and a first outer wall 53, and is made of metal. The first support wall 52 protrudes from the first wall 51. The first outer wall 53 protrudes from the first wall 51 shorter than the first support wall 52 and surrounds the first support wall 52 with a gap G therebetween. The substrate 36 has a first surface 36a, a second surface 36b, and an antenna 36d. The first surface 36a is supported by the first support wall 52. The second surface 36b is located opposite the first surface 36a. The antenna 36d is provided on the second surface 36b. The radome 42 has a second wall 71, a second support wall 72, a second outer wall 73, and a convex wall 74, and is made of a dielectric material. The second wall 71 covers the second surface 36b. The second support wall 72 supports the second surface 36b and holds the substrate 36 between the second wall 71 and the first support wall 52. The second outer wall 73 surrounds the first support wall 52 and the substrate 36. The convex wall 74 protrudes from the second outer wall 73 and is accommodated in the gap G, while surrounding the first support wall 52.

[0085] The tip 53a of the first outer wall 53 is formed to be outside the second outer wall 73, and the convex wall 74 is accommodated in the gap G between the first support wall 52 and the first outer wall 53. As a result, water infiltrating the first outer wall 53 and the second outer wall 73 from outside is blocked by the tip 53a of the first outer wall 53, the gap G, or the convex wall 74. That is, the relative positions of the tip 53a of the first outer wall 53 and the second outer wall 73, as well as the fit between the gap G and the convex wall 74, improve the drip-proof performance of the radar device 21 and prevent water from infiltrating into the case 41 and the radome 42. Furthermore, because the first outer wall 53 protrudes shorter than the first support wall 52, it is located behind the second surface 36b on which the antenna 36d is provided. Therefore, the power of the radio waves W2 emitted from the antenna 36d toward the first outer wall 53 is low. Therefore, the radar device 21 can reduce ringing caused by the radio waves W2 emitted by the antenna 36d being reflected by the first outer wall 53, and can prevent a deterioration in the directivity characteristics. For example, if the area of ​​the second surface 36b relative to the antenna 36d (the size of the substrate 36) becomes smaller, the reference potential of the substrate 36 becomes weaker, which may cause a deterioration in the directivity characteristics of the radar device 21. However, because the radar device 21 can prevent a deterioration in the directivity characteristics as described above, the size of the substrate 36 can be reduced, and the radar device 21 can be made more compact.

[0086] The radome 42 has a protrusion 75 that protrudes horizontally from the second outer wall 73 along the second surface 36b. For example, radio waves emitted from the antenna 36d may flow inside the radome 42, which is made of a dielectric material. The size of the radome 42 is expanded in the horizontal direction by the protrusion 75. As a result, the range of radio waves that pass through the radome 42 and are emitted from the radar device 21 is expanded in the horizontal direction, and the radar device 21 can expand its beam angle D.

[0087] The bracket 32 ​​holds the protrusion 75. The radome 42 is provided with an attachment portion 76 that is attached to the bracket 32 ​​by snap-fitting. That is, not only is the attachment portion 76 of the radome 42 attached to the bracket 32 ​​by snap-fitting, but the protrusion 75 is also held by the bracket 32. As a result, the protrusion 75 not only widens the beam angle D of the radar device 21, but also enables the radome 42 to be attached to the bracket 32 ​​more stably.

[0088] The screw 43 has a screw shaft 91 and a screw head 92. The screw shaft 91 fits into a screw hole 66 provided in the first support wall 52. The screw head 92 is provided at the end of the screw shaft 91. The screw 43 holds the board 36 between the screw head 92 and the first support wall 52. The case 41 has a plurality of guides 54. The plurality of guides 54 protrude from the first support wall 52 at a distance from each other and limit movement of the board 36 in the horizontal direction. The screw head 92 is farther away from the first support wall 52 than the plurality of guides 54.

[0089] The multiple guides 54 can position the board 36 placed on the first support wall 52, facilitating assembly of the radar device 21. Furthermore, if the board 36 is attached to the case 41 with the screws 43, an antenna 36d with sufficient performance can be provided even if there is an influence of the screws 43. The guides 54 protrude from the first support wall 52 by a distance smaller than the screws 43. Therefore, the radar device 21 can prevent the provision of the guides 54 from affecting the radio waves emitted from the antenna 36d.

[0090] The first support wall 52 has a support portion 61 and a plurality of protruding portions 62. The support portion 61 supports the first surface 36a on the inside of the edge of the first surface 36a. The plurality of protruding portions 62 are spaced apart from each other and protrude horizontally from the support portion 61. The plurality of guides 54 protrude from the plurality of protruding portions 62. This makes it difficult for radio waves emitted from the antenna 36d to be emitted toward the support portion 61. Furthermore, the protruding portions 62 only partially protrude from the support portion 61 and do not extend the first support wall 52 as a whole. Therefore, the radar device 21 can reduce ringing caused by radio waves emitted from the antenna 36d being reflected by the first support wall 52, and can prevent a deterioration in directivity characteristics.

[0091] While the embodiments of the present invention have been described above, the above-described embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above-described embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the configurations and shapes of each embodiment and each modification can be partially interchanged. [Explanation of symbols]

[0092] 21...radar device, 36...board, 36a...first surface, 36b...second surface, 36d...antenna, 41...case, 42...radome (cover), 43...screw, 51...first wall, 52...first support wall, 53...first outer wall, 53a...tip, 54, 54F, 54B, 54R, 54L...guide, 61...support portion, 62...extension portion, 66...screw hole, 71...second wall, 72...second support wall, 73...second outer wall, 74...convex wall, 75...protrusion, 91...screw shaft, 92...screw head, G...gap.

Claims

1. a case made of metal having a first wall, a first support wall protruding from the first wall, and a first outer wall protruding from the first wall to a shorter length than the first support wall and surrounding the first support wall with a gap; a substrate having a first surface supported by the first support wall, a second surface located opposite to the first surface, and an antenna provided on the second surface; a cover made of a dielectric material, the cover including: a second wall covering the second surface; a second support wall supporting the second surface and holding the substrate between the second support wall and the first support wall; a second outer wall surrounding the first support wall and the substrate; and a convex wall projecting from the second outer wall, accommodated in the gap, and surrounding the first support wall; A radar device comprising:

2. the cover has a protrusion that protrudes from the second outer wall in a direction along the second surface. The radar device according to claim 1 .

3. a screw having a screw shaft that fits into a screw hole provided in the first support wall and a screw head provided at an end of the screw shaft, and holding the substrate between the screw head and the first support wall; Furthermore, the case has a plurality of guides that protrude from the first support wall at a distance from each other and limit movement of the substrate in a direction along the second surface; the screw head is spaced farther from the first support wall than the guides are. The radar device according to claim 1 .

4. the first support wall has a support portion that supports the first surface on the inside of an edge of the first surface, and a plurality of protruding portions that are spaced apart from each other and protrude from the support portion in a direction along the second surface, The plurality of guides protrude from the plurality of overhanging portions. The radar device according to claim 3 .

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