JP6852623B2 - Radio wave transmission cover - Google Patents

Description

The present invention relates to a radio wave transmitting cover that is arranged in a radio wave path of a radio wave radar device and has one surface forming an outer surface of a vehicle.

It is practical to equip a vehicle such as an automobile with a radio wave radar device that radiates radio waves such as millimeter waves and microwaves and measures the reflected waves to detect obstacles and measure the distance between vehicles. ..

If this radio wave radar device is arranged in an exposed state with respect to the vehicle, the design of the vehicle may be impaired. Therefore, a plate-shaped radio wave transmitting cover (for example, Patent Document 1) hides the radio wave radar device from the outside of the vehicle so that one surface (design surface) is the outer surface of the vehicle on the outside of the vehicle. Be placed. Such a radio wave transmission cover has radio wave transmission property and is arranged so as to block the radio wave propagation path of the radio wave radar device. Therefore, it is possible to radiate radio waves from the radio wave radar device to the outside of the vehicle or to inject reflected waves from the outside of the vehicle to the radio wave radar device through the radio wave transmission cover.

Japanese Unexamined Patent Publication No. 2008-230497

In addition to the design performance of the design surface and the radio wave transmission performance, the radio wave transmission cover is required to have various performances such as impact resistance against collision of foreign substances. In order for the radio wave transmitting cover to exhibit high design performance and high impact resistance, the thicker the radio wave transmitting cover is, the more advantageous it is. On the other hand, in order for the radio wave transmission cover to exhibit high radio wave transmission performance, the thinner the radio wave transmission cover, the more advantageous it is. The radio wave transmission cover described in Patent Document 1 has a plate shape, and cannot be said to have a structure suitable for obtaining various performances.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a radio wave transmission cover capable of improving high performance.

The radio wave transmission cover for solving the above problems is a radio wave transmission cover arranged in the radio wave path of the radio wave radar device in a manner in which one surface forms the outer surface of the vehicle, and one surface is a plate forming the one surface. A rib that is erected at a position spaced from the outer peripheral edge of the cover body on a surface opposite to the one surface of the cover body and extends along the outer edge of the cover body. Have.

In the above configuration, the cover main body has a portion forming a design surface of the radio wave transmission cover and a portion through which the radio wave of the radio wave radar device is transmitted. According to the above configuration, since the ribs are erected on the cover body, the strength of the radio wave transmitting cover including the cover body can be increased as compared with the case where the ribs are not provided. As a result, the impact resistance performance of the radio wave transmission cover can be improved. Moreover, since the strength required for the cover body is reduced by the amount of ribs provided, the thickness of the cover body is made thin within the thickness range that can suppress the amount of radio wave attenuation to an appropriate amount and secure the design performance. can do.

Further, when the radio wave transmission cover is provided on the vehicle, a part of the radio wave (reflected wave) may be diffracted at the outer edge of the radio wave transmission cover and unnecessarily measured by the radio wave radar device.
According to the above configuration, since the ribs are erected at positions spaced apart from the outer peripheral edge of the cover body, the outer edge of the radio wave transmitting cover can be formed into a two-step stepped shape. Therefore, even if a part of the radio wave is diffracted at the outer edge of the radio wave transmitting cover by the knife edge effect, it can be diffracted at each step portion of the outer edge of the radio wave transmitting cover. Here, it is known that when a radio wave is diffracted, the intensity of the radio wave is weakened each time it is diffracted. According to the above configuration, since the radio wave can be diffracted a plurality of times at the outer edge of the radio wave transmission cover, the intensity of the radio wave directed to the radio wave radar device after the diffraction can be weakened, and the adverse effect of the radio wave can be mitigated. it can.

As described above, according to the above configuration, the radio wave transmission cover can have a structure that satisfies all of the design performance, the radio wave transmission performance, the impact resistance performance, and the radio wave diffraction performance, and the performance of the radio wave transmission cover can be improved. Can be planned.

In the radio wave transmission cover, the rib is provided at least at a portion where the virtual radio wave transmission range in which the radio wave transmission range through which the radio wave is transmitted is expanded in the extending direction of the polarization plane of the radio wave and the outer edge of the radio wave transmission cover overlap. It is preferable to be.

In the above configuration, ribs are arranged in a portion where the virtual radio wave transmission range and the outer edge of the radio wave transmission cover overlap, that is, a portion where radio wave diffraction may occur. Therefore, by utilizing this rib, the strength of the radio wave directed to the radio wave radar device after being diffracted can be accurately weakened, and the adverse effect of the radio wave can be suitably mitigated.

In the radio wave transmission cover, the ribs preferably extend in an annular shape along the outer edge of the cover body.
According to the above configuration, since the ribs have a tubular shape, the strength of the radio wave transmitting cover can be suitably increased. Moreover, regardless of the angle of the plane of polarization of the radio waves of the radio wave radar device, ribs are arranged at the portion where the virtual radio wave transmission range and the outer edge of the radio wave transmission cover overlap. Therefore, the radio wave transmission cover can be made highly versatile.

According to the present invention, it is possible to improve the performance of the radio wave transmission cover.

The schematic diagram which shows the schematic structure of the vehicle to which the radio wave transmission cover of one Embodiment is applied. Front view of the radio wave transmission cover. Sectional view of the radio wave transmission cover and its surroundings. Rear view of the radio wave transmission cover. Operation diagram of the radio wave transmission cover.

Hereinafter, an embodiment of the radio wave transmission cover will be described.
First, a schematic configuration of a vehicle to which the radio wave transmission cover of the present embodiment is applied will be described.
As shown in FIG. 1, a radio wave radar device 11 is mounted on the front portion of the vehicle 10. The radio wave radar device 11 detects the surrounding situation of the vehicle 10 by radiating a radio wave (millimeter wave) toward the front of the vehicle 10 (left side in FIG. 1) and measuring the reflected wave. The radio wave radar device 11 radiates radio waves so as to vibrate on a plane of polarization composed of a horizontal surface (specifically, a surface parallel to the road surface).

As shown in FIGS. 1 and 2, a radio wave transmission cover 20 is attached to the front portion of the vehicle 10. The radio wave transmission cover 20 is an exterior part (so-called emblem) in which a portion far from the radio wave radar device 11, that is, a portion outside the vehicle (front side on the paper in FIG. 2) forms an outer wall portion and a design portion of the vehicle 10. The radio wave radar device 11 is hidden from the outside of the vehicle 10 by the radio wave transmission cover 20.

The radio wave transmission cover 20 is arranged on the front side (left side of FIG. 1) of the radio wave radar device 11 so as to block the radio wave propagation path (white arrow in FIG. 1) of the radio wave radar device 11. Specifically, the radio wave radiated from the radio wave radar device 11 and the reflected wave measured by the device 11 pass through the central portion of the radio wave transmission cover 20 (the radio wave transmission portion 21 shown by the one-point chain line in FIG. 2). The radio wave transmission cover 20 is arranged on the outside of the vehicle of the radio wave radar device 11.

Next, the structure of the radio wave transmission cover 20 will be specifically described.
The radio wave transmission cover 20 has a plate-shaped cover body 22 (thickness 6 mm in the present embodiment) having a substantially elliptical shape when viewed from the front (viewed by arrow A in FIG. 1).

As shown in FIG. 3, the cover main body 22 has an inner surface covering plate 23, a coating layer 24, a metal film layer 25, an outer surface covering plate 26, and a hard coat layer 27 in this order from the inside of the vehicle (lower side of FIG. 3). It has a multi-layer structure. In FIG. 3, the thickness of the coating layer 24, the thickness of the metal film layer 25, and the thickness of the hard coat layer 27 are exaggerated from the actual thickness in order to facilitate understanding.

The inner surface coating plate 23 is formed of acrylonitrile-ethylene-styrene resin (AES resin), and the coating layer 24 is formed of a black acrylic paint. The metal film layer 25 is an island-like film made of indium. The outer coating plate 26 is made of transparent polycarbonate (PC), and the hard coat layer 27 is made of transparent acrylic resin.

These AES resin (inner surface coating plate 23), acrylic paint (painting layer 24), PC (outer surface coating plate 26), and acrylic resin (hard coat layer 27) are all materials having radio wave transmittance that transmit radio waves. is there. Further, the island-shaped film (metal film layer 25) made of indium has radio wave transmittance for transmitting radio waves. Therefore, the cover body 22 of the radio wave transmission cover 20 has radio wave transmission property for transmitting radio waves.

Further, the cover main body 22 has a structure in which a transparent outer surface covering plate 26, a metal-colored metal film layer 25, and a black coating layer 24 are laminated in this order from the outside of the vehicle. Therefore, as shown in FIG. 2, when viewed from the outside of the vehicle, the cover main body 22 has a metal color (metal film layer 25) pattern on a black background (painting layer 24) (in the present embodiment, an outer frame and letters [A]. ]) Is visible.

As shown in FIGS. 3 and 4, on the surface of the cover body 22 opposite to the design surface (the surface on the front side of the paper surface of FIG. 4), ribs 28 extending in an annular shape along the outer edge of the cover body 22 Is erected. The rib 28 projects toward the rear of the vehicle 10 at a position at a distance (distance) from the outer peripheral end of the cover body 22 (in this embodiment, the protrusion amount is 8 mm), and the cover body 22 (details). Is formed integrally with the inner surface covering plate 23). The rib 28 is made of the same material (AES resin) as the inner surface coating plate 23.

In FIGS. 2 and 4, the radio wave transmission range (radio wave transmission unit 21) through which the radio wave of the radio wave radar device 11 is transmitted and the direction in which the radio wave polarization plane extends through the radio wave transmission unit 21 (horizontal direction in the present embodiment). ) Indicates the expanded virtual radio wave transmission range AR. As is clear from FIGS. 2 and 4, the arranged portion of the rib 28 is a portion of the outer edge of the radio wave transmission cover 20 (specifically, the cover body 22) that overlaps with the virtual radio wave transmission range AR (FIGS. 2 and 4). FIG. 4 includes all of (the part indicated by “B”).

As shown in FIG. 4, a plurality of (three in the present embodiment) convex portions 29 projecting outward are provided on the outer peripheral surface of the rib 28 at intervals in the circumferential direction.
Next, the mounting structure of the radio wave transmission cover 20 will be described.

As shown in FIG. 3, the front grill 12 of the vehicle 10 is provided with a stepped mounting cylinder portion 13 so as to extend in the front-rear direction (vertical direction in FIG. 3). The front portion of the mounting cylinder portion 13 is a large diameter portion 14, the rear portion is a small diameter portion 15, and the boundary between the large diameter portion 14 and the small diameter portion 15 is a step portion 16. It has become. A plurality of (three in the present embodiment) engaging holes (not shown) are formed in the large diameter portion 14 of the mounting cylinder portion 13 at intervals in the circumferential direction. These engaging holes are located at positions facing the convex portion 29 (see FIG. 4) of the rib 28 of the radio wave transmitting cover 20 in a state where the radio wave transmitting cover 20 is attached to the front grill 12 (the state shown in FIG. 3). Is formed in.

Then, when the radio wave transmission cover 20 is attached, the rib 28 of the radio wave transmission cover 20 is inserted into the mounting cylinder portion 13 of the front grill 12, and each convex portion 29 of the rib 28 is each engaging hole of the mounting cylinder portion 13. It is fitted in. As a result, the rib 28 of the radio wave transmission cover 20 is locked to the mounting cylinder portion 13 of the front grill 12. At this time, the stepped portion 16 of the mounting cylinder portion 13 of the front grill 12 and the outer edge of the rear surface of the cover main body 22 of the radio wave transmission cover 20 are in a state of facing each other.

By attaching the radio wave transmitting cover 20 in this way, a step portion 16 of the mounting cylinder portion 13 is arranged behind the gap between the radio wave transmitting cover 20 and the mounting cylinder portion 13 (large diameter portion 14) of the front grill 12. Will be done. As a result, the gap is less noticeable when the radio wave transmission cover 20 is viewed from the front.

Hereinafter, the action and effect of the radio wave transmission cover 20 of the present embodiment will be described.
In the present embodiment, the cover main body 22 of the radio wave transmitting cover 20 forms a design surface of the radio wave transmitting cover 20 (a portion outside the vehicle) and a portion through which radio waves of the radio wave radar device 11 are transmitted (radio wave transmitting portion 21). have.

In the present embodiment, the rib 28 is erected on the inner surface of the cover body 22. Since the rib 28 functions as a reinforcing member for reinforcing the radio wave transmitting cover 20 (specifically, the cover body 22), the strength of the radio wave transmitting cover 20 including the cover body 22 is increased as compared with the one without the rib. Can be high. As a result, the impact resistance performance of the radio wave transmission cover 20 can be improved.

Moreover, the strength required for the cover main body 22 is lowered by the amount of the rib 28 provided. Therefore, the thickness of the cover body (6 mm in this embodiment) can be reduced within a thickness range in which the amount of radio wave attenuation can be suppressed to an appropriate amount and the design performance can be ensured.

Further, as shown by an example in FIG. 5, when the radio wave transmission cover 20 is provided on the vehicle 10, a part of the radio wave (reflected wave) of the radio wave radar device 11 is diffracted at the outer edge of the radio wave transmission cover 20 to be the same. It may be unnecessarily measured by the radio wave radar device 11.

In the present embodiment, since the rib 28 is erected at a position spaced from the outer peripheral end of the cover main body 22, the outer edge of the radio wave transmitting cover 20 has a two-step stepped shape.
Therefore, even if a part of the radio wave is diffracted by the knife edge effect at the outer edge of the radio wave transmitting cover 20, the radio wave can be diffracted at the stepped portions 31 and 32 of the outer edge of the radio wave transmitting cover 20. Here, it is known that when a radio wave is diffracted, the intensity of the radio wave is weakened each time it is diffracted. According to the present embodiment, the radio wave can be diffracted a plurality of times (twice in the present embodiment) at the outer edge of the radio wave transmitting cover 20. Therefore, the strength of the radio wave (arrow S1 in FIG. 5) directed to the radio wave radar device 11 after being diffracted at each of the step portions 31 and 32 can be weakened, and the radio wave S1 is detected by the radio wave radar device 11 and has an adverse effect. Can be alleviated.

Further, a part of the radio wave (arrow S2 in FIG. 5) diffracted at the first step portion 31 (outer edge end of the cover main body 22) in the two-step step shape also goes toward the radio wave radar device 11. However, the traveling direction of the radio wave S2 is blocked by the rib 28. Therefore, the strength of the radio wave S2 can be weakened by reflecting a part of the radio wave S2 on the outer surface of the rib 28 or transmitting the rib 28 to weaken the radio wave strength, and the radio wave S2 is the radio wave radar device 11. The adverse effects of being detected by can be mitigated.

As described above, according to the present embodiment, the radio wave transmission cover 20 can have a structure that satisfies all of the design performance, the radio wave transmission performance, the impact resistance performance, and the radio wave diffraction performance, and the height of the radio wave transmission cover 20 is high. Performance can be improved.

From the results of various experiments and simulations by the inventor and the like, by adopting the radio wave transmission cover 20 of the present embodiment having the rib 28, the radio wave transmission cover of the comparative example having no rib 28 is adopted. It has been confirmed that the amount of attenuation of the radio wave (reflected wave) accompanying the transmission of the radio wave transmission cover 20 is reduced by about 15% as compared with the case. The shape of the rib 28 is the distance from the outer peripheral end of the cover main body 22, in other words, the outer peripheral end (step portion 32) of the rib 28 and the cover main body 22 in the direction orthogonal to the front-rear direction (left-right direction in the example shown in FIG. 5). It is desirable that the shape is such that the distance (“W” in FIG. 5) from the outer peripheral edge (step portion 31) is in the range of “3 mm to 70 mm”. The shape of the rib 28 is the amount of protrusion from the cover main body 22, in other words, the distance between the outer peripheral rear end (step portion 32) of the rib 28 and the outer peripheral rear end (step portion 31) of the cover main body 22 in the front-rear direction (FIG. 5). It is desirable that the "H") inside has a shape in the range of "1 mm to 15 mm".

Further, in the present embodiment, since the ribs 28 extending rearward are provided at positions spaced apart from the outer peripheral end of the cover main body 22, such ribs are provided at the outer peripheral end of the cover body 22 as compared with those provided. The thickness of the portion corresponding to the outer peripheral edge of the radio wave transmission cover 20 in the front-rear direction can be reduced. Therefore, of the portions of the radio wave transmission cover 20 that form the outer surface of the vehicle 10 (left surface, upper surface, and lower surface of FIG. 1), the outer edges of the cover main body 22 extend backward while being curved (upper surface and lower surface of FIG. 1). ) Depth (length in the left-right direction in FIG. 1) becomes shorter. This makes it possible to easily form the hard coat layer 27 on the portion of the radio wave transmission cover 20 that forms the outer surface of the vehicle 10.

Further, in the radio wave transmitting cover 20 of the present embodiment, the rib 28 extends in an annular shape (cylindrical shape) along the outer edge of the cover main body 22. Therefore, the strength of the radio wave transmitting cover 20 can be suitably increased as compared with the one provided with the rib having a shape in which a part is interrupted in the circumferential direction.

Further, the cover main body includes a portion where the virtual radio wave transmission range AR and the outer edge of the radio wave transmission cover 20 overlap, that is, a portion where radio wave diffraction may occur (a portion indicated by “B” in FIGS. 2 and 4). Ribs 28 will be placed on all parts of the outer edge of 22. Therefore, the rib 28 can be used to accurately weaken the intensity of the radio wave directed to the radio wave radar device 11 after being diffracted by the outer edge of the radio wave transmitting cover 20, and the adverse effect of the radio wave can be suitably mitigated.

Moreover, regardless of the angle of the polarization plane of the radio wave of the radio wave radar device 11, the rib 28 is arranged at the portion where the virtual radio wave transmission range AR and the outer edge of the radio wave transmission cover 20 overlap. Therefore, the radio wave transmission cover 20 should be diverted to a vehicle whose plane tilted 45 degrees with respect to the horizontal plane is the plane of polarization of radio waves and a vehicle whose vertical surface (specifically, the plane orthogonal to the road surface) is the plane of polarization of radio waves. The radio wave transmission cover 20 can be made highly versatile.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) The radio wave transmission cover 20 can have a structure that satisfies all of the design performance, the radio wave transmission performance, the impact resistance performance, and the radio wave diffraction performance, and the performance of the radio wave transmission cover 20 can be improved. ..

(2) Using the rib 28 arranged at the portion where the virtual radio wave transmission range AR and the outer edge of the radio wave transmission cover 20 overlap, the strength of the radio wave directed to the radio wave radar device 11 after being diffracted by the outer edge of the radio wave transmission cover 20 is determined. It can be accurately weakened, and the adverse effects of the same radio wave can be suitably mitigated.

(3) A rib 28 extending in an annular shape along the outer edge of the cover main body 22 is provided on the cover main body 22. Therefore, the strength of the radio wave transmission cover 20 can be suitably increased. Moreover, the radio wave transmission cover 20 can be made highly versatile.

<Modification example>
The above embodiment may be modified as follows.
-The material forming each layer of the radio wave transmission cover 20 (inner surface coating plate 23, coating layer 24, metal film layer 25, outer surface coating plate 26, hard coat layer 27) is such that radio waves of appropriate strength can be transmitted. , Can be changed arbitrarily.

-A part of the rib 28 extending in a ring shape along the outer edge of the cover main body 22 may be omitted.
In this case, it is desirable to arrange the rib 28 at least in the portion where the virtual radio wave transmission range AR and the outer edge of the radio wave transmission cover 20 overlap (the portion indicated by “B” in FIGS. 2 and 4). As a result, the rib 28 can be arranged in the portion where the radio wave may be diffracted. Therefore, the rib 28 is used to diffract the radio wave at the outer edge of the radio wave transmission cover 20 and then direct the radio wave toward the radio wave radar device 11. It is possible to accurately weaken the strength of.

Further, in the above embodiment, a part of the radio waves radiated from the radio wave radar device 11 does not pass through the radio wave transmitting cover 20, but is formed by the back surface (inner surface of the vehicle) of the radio wave transmitting cover 20 and the inner surface of the rib 28. It is conceivable that a phenomenon such as reflection and unnecessarily returning to the radio wave radar device 11 may occur. In this regard, by omitting a part of the rib 28 as in the above configuration, a part of the wall (specifically, the rib 28) that further reflects the radio wave reflected by the back surface of the radio wave transmitting cover 20 is omitted. Therefore, the occurrence of the above phenomenon can be suppressed.

-The radio wave transmission cover 20 of the above embodiment can also be applied to a vehicle in which a radio wave radar device that radiates radio waves toward the rear of the vehicle is provided at the rear of the vehicle. In this case, the radio wave transmission cover 20 may be arranged in the radio wave propagation path on the rear side of the vehicle of the radio wave radar device.

-The radio wave transmission cover 20 of the above embodiment can also be applied to a vehicle equipped with a radio wave radar device that emits microwaves.

10 ... Vehicle, 11 ... Radio radar device, 12 ... Front grille, 13 ... Mounting cylinder, 14 ... Large diameter, 15 ... Small diameter, 16 ... Step, 20 ... Radio transmission cover, 21 ... Radio transmission, 22 ... Cover body, 23 ... Inner surface coating plate, 24 ... Coating layer, 25 ... Metal film layer, 26 ... Outer surface coating plate, 27 ... Hard coat layer, 28 ... Ribs, 29 ... Convex parts, 31, 32 ... Stepped parts.

Claims (3)

It is a radio wave transmission cover that is placed in the radio wave path of the radio wave radar device so that one side forms the outer surface of the vehicle.
A plate-shaped cover body whose one surface forms one surface, and
From said one surface of said cover body is erected on the opposite side, have a, and ribs extending along the outer edge of the cover body,
The rib is a radio wave transmission cover erected at a position spaced from the outer peripheral end of the cover body so as to diffract the radio wave toward the radio wave radar device after being diffracted by the outer edge of the radio wave transmission cover. The rib is provided at least in a portion where the virtual radio wave transmission range obtained by expanding the radio wave transmission range through which the radio wave is transmitted in the extending direction of the polarization plane of the radio wave and the outer edge of the radio wave transmission cover overlap, according to claim 1. Radio wave transmission cover. The radio wave transmission cover according to claim 1 or 2, wherein the rib extends in a ring shape along the outer edge of the cover body.

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