WO2019035296A1

WO2019035296A1 - Radio-wave transmission cover

Info

Publication number: WO2019035296A1
Application number: PCT/JP2018/026344
Authority: WO
Inventors: 雄大鈴木; 幸蔵廣谷
Original assignee: 豊田合成株式会社
Priority date: 2017-08-16
Filing date: 2018-07-12
Publication date: 2019-02-21
Also published as: JP2019035667A

Abstract

A radio-wave transmission cover (20) is disposed in a radio-wave propagation path of a radio-wave radar device. Heating wires (31) are integrally provided on the radio-wave transmission cover (20). In a radio-wave transmission section 21 of the radio-wave transmission cover (20), a plurality of hot wire sections (31A), forming portions of the heating wires (31), are disposed at intervals. At least some of the hot wire sections (31A) extend in a regular pattern in which the bending directions are alternately changed towards one direction in the extension directions of said hot wire sections (31A).

Description

Radio wave transmission cover

The present invention relates to a radio wave transmission cover disposed in a radio wave path of a radio wave radar device.

It has been put into practical use to mount a radio wave radar device that detects obstacles and measures inter-vehicle distance by emitting radio waves such as millimeter waves and microwaves and measuring the reflected waves in vehicles such as automobiles. .

If this radio wave radar device is disposed in a state of being exposed to the vehicle, the design of the vehicle may be impaired. Therefore, the radar device is disposed at a position inside the radio wave transmission cover (such as an emblem) having one surface that constitutes the outer surface of the vehicle, in such a manner as to be concealed from the vehicle exterior by the radio wave transmission cover. The radio wave transmission cover has radio wave transmission. Therefore, radiation of radio waves from the radar apparatus to the outside of the vehicle and incidence of reflected waves from the outside of the vehicle to the radar apparatus are possible through the radio wave transmission cover.

When moisture such as ice or snow adheres to the surface of the radio wave transmission cover, the amount of attenuation of the radio wave at the time of transmission of the radio wave transmission cover increases, and the detection accuracy of the radar device is lowered. In view of this point, it has been proposed to attach the heating wire to the radio wave transmission cover (for example, Patent Document 1). Water is removed by energizing the heating wire to heat the radio wave transmission cover.

In this case, if the heating wire is simply disposed at a portion (radio wave transmitting portion) in the radio wave transmission cover through which radio waves are transmitted, the heating wire may greatly attenuate the radio waves, which may cause the performance of the radar device to deteriorate. In this respect, in the radio wave transmission cover of Patent Document 1, the extending direction of the heating wire in the radio wave transmission portion is determined in the direction orthogonal to the polarization plane of the radio wave. Thereby, attenuation of the radio wave at the time of penetration of the radio wave transmission cover is suppressed.

Japanese Patent Publication No. 2003-518633

In order to remove the moisture adhering to the radio wave transmission part of the radio wave transmission cover, it is desirable to arrange the heating wire over the whole radio wave transmission part and to heat the radio wave transmission part evenly. In the radio wave transmission cover of Patent Document 1, although the reduction of the performance of the radio wave radar device due to the attenuation of radio waves is suppressed, the extending direction of the heating wire in the radio wave transmission cover is limited to the direction orthogonal to the polarization plane. . Therefore, in the radio wave transmission cover of Patent Document 1, there is a possibility that the heating wire can not be properly disposed on the radio wave transmission cover.

An object of the present invention is to provide a radio wave transmission cover which can arrange heating wires with a high degree of freedom.

The radio wave transmission cover for solving the above problems is a radio wave transmission cover that transmits the radio wave in the radio wave transmission cover that is integrally provided with a heating wire and configured to be disposed in the radio wave path of the radio wave radar device. A plurality of heat wire parts forming a part of the heating wire are disposed at intervals in the part, and at least a part of the plurality of heat wire parts is moved toward one side in the extending direction of the heat wire parts. The bending direction extends in a regular pattern alternating with each other.

In the radio wave transmission cover integrally provided with the heating wire, the attenuation amount of the radio wave is particularly large when the heating wire extends linearly so that the polarization plane of the radio wave coincides with the extending direction of the heating wire. Become.
According to the above configuration, in the portion of the heating wire extending in the regular pattern, it is possible to shorten the total length of the portion (hereinafter referred to as a specific portion) in which the heating wire extends continuously in a straight line. Alternatively, according to the above configuration, such a specific part can be eliminated. Thereby, at least for the portion extending in the above regular pattern, the above-mentioned specification that the attenuation of the radio wave becomes particularly large when the extending direction of the heating wire coincides with the polarization plane of the radio wave transmitted through the radio wave transmission cover Since the number of parts can be reduced, the degree of freedom of the arrangement of the heating wires can be increased. Therefore, the heating wire can be disposed on the radio wave transmission cover with a high degree of freedom.

In the radio wave transmission cover, it is preferable that all parts of the plurality of heat ray parts extend in the regular pattern.
According to the above configuration, the specific portions can be reduced in all the portions of the plurality of heat ray portions, and therefore the attenuation amount of the radio wave can be reduced regardless of the arrangement of the heat ray portions. Therefore, the heating wire (more specifically, a plurality of heating wire portions) can be disposed on the radio wave transmission cover with a higher degree of freedom. Moreover, since the attenuation amount of the radio wave can be reduced without finely setting the relationship between the polarization plane of the radio wave and the arrangement of the heating wires, that is, the relationship between the radio wave radar device and the radio wave transmission cover, versatility of the radio wave transmission cover is improves.

In the radio wave transmission cover, preferably, the regular pattern is formed of only a curve.
According to the above configuration, the specific portion can be eliminated in the portion of the heating wire extending in the regular pattern. Therefore, the degree of freedom in the arrangement of the heating wire on the radio wave transmission cover can be suitably increased.

The radio wave transmission cover is an exterior part where a portion far from the radio wave radar device forms an outer wall portion and a design portion of the vehicle, and the heating wire is provided on the far portion.
According to the above-described configuration, the water adhering to the outer surface of the radio wave transmission cover is heated compared to the case where the heating wire is provided on the side closer to the radio wave radar device (inside the vehicle) in the radio wave transmission cover Can be efficiently removed. Moreover, the heating wire can be disposed with a high degree of freedom while suppressing the deterioration of the design of the radio wave transmission cover with respect to the design portion forming the outer wall of the radio wave transmission cover.

According to the radio wave transmission cover of the present invention, the heating wire can be arranged with a high degree of freedom.

The schematic diagram which shows schematic structure of the vehicle to which the electromagnetic wave transmission cover of one Embodiment is applied. Front view of a radio wave transmission cover. The side sectional view of an electric wave penetration cover. Sectional drawing of a heat-generating sheet. (A) is a front view which shows the arrangement | positioning aspect of a heat generating sheet, (b) is a bottom view which shows the arrangement | positioning aspect of a heat generating sheet. The schematic diagram which shows the relationship between the extension direction of a heating wire, and the polarization plane of an electromagnetic wave. (A) is an action view of the radio wave transmission cover of the embodiment, (b) is an action view of the radio wave transmission cover of the comparative example.

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 of a vehicle 10. The radio wave radar device 11 radiates a radio wave (millimeter wave) toward the front (left side in FIG. 1) of the vehicle 10 and measures the reflected wave to detect the surrounding condition of the vehicle 10. The radio wave radar device 11 radiates a radio wave so as to vibrate on a polarization plane which is a horizontal plane. In addition, the said horizontal surface is a surface parallel to a road surface in more detail.

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

The radio wave transmission cover 20 has a horizontally long rectangular plate shape, and is disposed on the front side of the radio wave radar device 11 so as to block the propagation path of the radio wave of the radio wave radar device 11. In FIG. 1, the propagation path of the radio wave of the radio wave radar device 11 is indicated by an open arrow. More specifically, the radio wave radar device 11 is disposed on the inner side of the radio wave transmission cover 20 in a mode in which all of the radio wave emitted 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. Is located in The central portion of the radio wave transmission cover 20 corresponds to a portion surrounded by an alternate long and short dash line in FIG.

The radio wave transmission cover 20 has a heat generating sheet 22 covering a portion on the outside of the vehicle. The heat generating sheet 22 incorporates a heating wire. As shown in FIG. 1, the heat generating sheet 22 (specifically, its heating wire) is connected to the storage battery 13 via the switch 12. When the switch 12 is turned on, the heating wire is energized to generate heat. As the switch 12, a switch manually operated by an occupant or a switch automatically operated according to the ambient temperature can be adopted.

Next, the structure of the radio wave transmission cover 20 will be specifically described.
As shown in FIG. 3, the radio wave transmission cover 20 has an inner surface covering plate 23, a paint layer 24, a metal film layer 25, an outer surface covering plate 26, and the heat generating sheet 22 in order from the vehicle inner side (right side in FIG. 3). It has a multilayer structure. In FIG. 3, the thickness of the paint layer 24, the thickness of the metal film layer 25, and the thickness of the heat-generating sheet 22 are shown exaggerating the actual thickness in order to facilitate understanding.

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

The AES resin (inner surface covering plate 23), the acrylic paint (painted layer 24), and the PC (outer surface covering plate 26) are all materials having radio wave transparency to transmit radio waves. In addition, the island-like film (metal film layer 25) made of indium has radio wave transparency to transmit radio waves. Therefore, the inner surface coating plate 23, the coating layer 24, the metal film layer 25, and the outer surface coating plate 26 of the radio wave transmission cover 20 all have radio wave transmission properties for transmitting radio waves.

The radio wave transmission cover 20 has a structure in which a transparent outer surface covering plate 26, a metal film layer 25 of metal color, and a black paint layer 24 are sequentially stacked from the vehicle outer side. Therefore, as shown in FIG. 2, when viewed from the outside of the vehicle, the radio wave transmission cover 20 can visually recognize a pattern consisting of the black ground of the paint layer 24 and the metal color of the metal film layer 25. In the present embodiment, as shown in FIG. 2, the outer frame and the letter [A] are visible when viewed from the outside of the vehicle.

As shown in FIG. 4, FIG. 5 (a) and FIG. 5 (b), the heat generating sheet 22 is comprised by the several heating wire 31, the connecting

terminals

32 and 33, and the two

films

34 and 35. . The two

films

34 and 35 are provided so as to sandwich the plurality of heating wires 31 and the

connection terminals

32 and 33 therebetween. The heating wire 31 and the

connection terminals

32, 33 are made of copper foil. The two

films

34, 35 are made of transparent polycarbonate (PC). In FIG. 4, the thickness of the

films

34 and 35 and the thickness of the heating wire 31 are shown exaggerating the actual thickness in order to facilitate understanding.

The heat generating sheet 22 is formed as follows. First, the heating wire 31 and the

connection terminals

32, 33 are formed on the surface of the film 34 in a predetermined pattern (see FIGS. 5A and 5B) by etching or printing. Thereafter, the two

films

34 and 35 are pasted together so as to sandwich the heating wire 31 and the

connection terminals

32 and 33 therebetween. Then, as shown in FIG. 3, the heat generating sheet 22 is integrally formed on the outer surface covering plate 26 so as to cover the entire outer side of the outer surface covering plate 26. As shown in FIG. 5 (b), the portions of the heat generating sheet 22 provided with the

connection terminals

32 and 33 extend from the lower end of the radio wave transmission cover 20 to the inner side of the vehicle (below the FIG. 5 (b)). ing. Moreover, since only the film 35 is provided at the tip of the extension portion of the radio wave transmission cover 20, the

connection terminals

32, 33 are exposed to the outside. And the part exposed to the exterior in the

connection terminals

32 and 33 is connected to the switch 12 (refer FIG. 1).

In the present embodiment, the heat generating sheet 22 (the heating wire 31) is provided on a portion of the radio wave transmission cover 20 outside the vehicle. Therefore, it is possible to efficiently remove the moisture attached to the surface of the radio wave transmission cover 20 on the vehicle outer side by the heat generation of the heat generating sheet 22 as compared with the case where the heating wire is provided on the vehicle inside of the radio wave transmission cover 20 It is. However, if the heating wire 31 is too thick, the design of the radio wave transmission cover 20 becomes difficult to see, and the design of the radio wave transmission cover 20 may be degraded. Therefore, in the present embodiment, the heating wire 31 is formed thin enough not to interfere with the recognition of the pattern of the radio wave transmission cover 20.

Further, in the present embodiment, the heating wire 31 is disposed also in the radio wave transmission portion 21 through which radio waves are transmitted in the radio wave transmission cover 20, so the attenuation amount of radio waves transmitting through the radio wave transmission cover 20 may be increased by the heating wire 31. is there. In view of this point, in the present embodiment, the heating wire 31 is disposed in a mode in which attenuation of radio waves can be appropriately suppressed.

Hereinafter, the arrangement of the heating wires 31 in the radio wave transmission cover 20 will be described in detail.
As shown in FIGS. 5 (a) and 5 (b), the heating wire 31 extends in a regular pattern in which almost all of the heating wires 31 alternate in bending directions toward one in the extending direction. ing. That is, almost all parts of the heating wire 31 extend in a sine-curve basic pattern. Thereby, the heating wire 31 is comprised only by the part extended by a curve.

The radio wave transmission cover 20 is provided with a plurality of heating wires 31 each extending in the basic pattern. In the present embodiment, seven heating wires 31 are provided. The plurality of heating wires 31 are arranged at substantially equal intervals over the entire portion of the radio wave transmission cover 20 outside the vehicle so that the connection terminals 32 and the connection terminals 33 are connected to each other. Specifically, among the plurality of heating wires 31, the heating wires 31 disposed on the outer edge side of the radio wave transmission cover 20 (right side part, left side part and upper part in FIG. 5A) are the radio wave transmission cover 20 It extends in a substantially reverse U-shape along the outer edge of the. Moreover, the heating wire 31 arrange | positioned in the center part (The center part of the downward side in FIG. 5 (a)) of several electric heating wire 31 is extended in the substantially rectangular wave form.

In the present embodiment, in the radio wave transmission part 21 of the radio wave transmission cover 20, a plurality of heat ray parts 31A, each of which forms a part of the heating wire 31, are arranged at intervals. All parts of the heat ray parts 31A extend in a basic pattern.

Hereinafter, the effect | action by arrange | positioning the heating wire 31 (heat wire part 31A) in this way is demonstrated.
As shown in FIG. 6, in the present embodiment, the radio wave transmitted from the radio wave radar device 11 and its reflected wave, that is, the radio wave W vibrating on the polarization plane S composed of a horizontal surface Will be transparent. On the other hand, a part of the heating wire 31 (heat wire part 31A) disposed in the radio wave transmission part 21 extends in the horizontal direction. Therefore, in the radio wave transmission part 21 of the radio wave transmission cover 20, the polarization plane S of the radio wave W transmitted through the radio wave transmission part 21 and the extending direction of the heating wire 31 disposed in the radio wave transmission part 21 partially coincide. Do.

As schematically shown in FIG. 7B, in the radio wave transmission cover of the comparative example in which the heating wire H is integrally provided, the polarization plane S of the radio wave W of the radio wave radar device and the extending direction of the heating wire H are When the heating wire H linearly extends in a coincident state, the attenuation amount of the radio wave W becomes particularly large. This is due to the following reasons. That is, the radio wave W is attenuated when passing through the heating wire H which is a conductor. When the extending direction and position of the linear heating wire H coincide with the polarization plane S of the radio wave W, the portion where the heating wire H coincides with the polarization plane S of the radio wave W is linear. Therefore, the portion where the radio wave W passes through the conductor (heating wire H) is relatively large, and the attenuation amount of the radio wave W becomes large.

In this respect, in the present embodiment, as conceptually shown in FIG. 7A, although the plane of polarization S of the radio wave W and the extending direction of the heating wire 31 partially coincide with each other, the heating wire 31 has a sign It extends in a curved basic pattern. Thus, since the extended shape of the heating wire 31 (heat wire portion 31A) is formed only by a curve, it is possible to eliminate a portion (hereinafter referred to as a specific portion) in which the heating wire 31 extends linearly continuously. it can. Therefore, when the extension direction of the heating wire 31 and the polarization plane S of the radio wave W coincide with each other, the part where the attenuation amount of the radio wave W becomes particularly large can be eliminated.

That is, according to the present embodiment, even when the extending direction and the arrangement position of the heating wire 31 coincide with the polarization plane S of the radio wave W, the heating wire 31 coincides with the polarization plane S of the radio wave W. The parts that are to be Therefore, compared to the case shown in FIG. 7 (b) in which the portion where the polarization plane S of the radio wave W matches the heating wire 31 is linear, the portion where the radio wave W passes through the conductor (heating wire 31) is The amount of attenuation of the radio wave W is reduced because it decreases.

By arranging the heating wire 31 of the basic pattern on the radio wave transmission cover 20 as described above, the attenuation of the radio wave is reduced even when the extending direction of the heating wire 31 matches the polarization plane of the radio wave. Ru. Thus, the restriction on the extending direction of the heating wire 31 in the radio wave transmission cover 20 is alleviated, so the heating wire 31 can be disposed on the radio wave transmission cover 20 with a high degree of freedom.

Moreover, in the radio wave transmission cover 20, all the portions of the heating wire 31 extend in a sine curve-like basic pattern, so that the specific portions can be eliminated in all the portions of the heating wire 31. Therefore, even if the heating wire 31 is disposed in any manner with respect to the radio wave transmission cover 20, the attenuation amount of the radio wave is reduced. As a result, the amount of attenuation of the radio wave can be reduced without setting the relationship between the polarization plane of the radio wave and the extending direction of the heating wire 31, that is, the relationship between the radio wave radar device 11 and the radio wave transmission cover 20 so strictly. Therefore, the radio wave transmission cover 20 is applied to a vehicle constituted by a plane in which the polarization plane of the radio wave is inclined 45 degrees with respect to the horizontal plane or a vehicle constituted by a vertical plane (in detail, a plane orthogonal to the road surface) Can be diverted. Therefore, the versatility of the radio wave transmission cover 20 is improved.

In the radio wave transmission cover where the polarization plane of the radio wave and the extending direction of the heating wire coincide, all parts of the heating wire are made linear by making all parts of the heating wire a basic pattern It has been confirmed from the results of various experiments and simulations by the inventors etc. that the attenuation amount of the radio wave transmitted through the radio wave transmission cover is reduced compared to the above.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) The heat wire portion 31A extends in a regular pattern (basic pattern) in which the bending direction is alternately switched toward one side in the extending direction of the heat wire portion 31A. Therefore, the heating wire 31 can be disposed on the radio wave transmission cover 20 with a high degree of freedom.

(2) All parts of the heat ray part 31A extend in the basic pattern. Since the said specific part can be lose | eliminated in all the parts of the heating wire 31 by this, the heating wire 31 can be arrange | positioned to the electromagnetic wave transmission cover 20 with a higher freedom degree. In addition, the amount of attenuation of the radio wave can be reduced without setting the relationship between the polarization plane of the radio wave and the extending direction of the heating wire 31, that is, the relationship between the radio wave radar device 11 and the radio wave transmission cover 20 so strictly. The versatility of the transparent cover 20 is improved.

(3) The heating wire 31 is provided on the outer side of the radio wave transmission cover 20 functioning as an emblem. The heating wire 31 is disposed at a high density in a portion having a small influence on the reduction in design in the design portion forming the outer wall of the radio wave transmission cover 20, thereby suppressing the deterioration in the designability of the radio wave transmission cover 20. Can be arranged with a high degree of freedom.

<Modification>
The above embodiment may be modified as follows.
The material for forming each layer of the radio wave transmission cover 20 (the inner surface coating plate 23, the coating layer 24, the metal film layer 25, and the outer surface coating plate 26) is arbitrarily changed as long as radio waves of appropriate strength are transmitted. It is possible.

The heating wire 31 disposed in a portion other than the radio wave transmission portion 21 of the radio wave transmission cover 20 may extend in a straight line, not in the basic pattern, or may extend in a gentle curve. .

· In the part where the extending direction of the heating wire 31 and the in-plane direction of the polarization plane of the radio wave are largely different, the heating wire 31 is extended not linearly with the basic pattern but in a straight line or a gentle curve. You may That is, in the above embodiment, the heating wire 31 is linearly extended or extended so as to draw a gentle curve in a portion where the extending direction of the heating wire 31 and the polarization plane of the radio wave are substantially orthogonal to each other. May be

-The extended shape of the heating wire 31 can be made into the shape comprised only by circular arc instead of a basic pattern, or can be made into a triangular wave shape. The point is that a regular pattern in which the directions of bending alternately change toward one side in the extending direction of the heating wire 31 can be adopted as the extending shape of the heating wire 31.

The heating wire 31 may be provided on a portion of the radio wave transmission cover 20 on the inner side of the vehicle. In this case, since there is no restriction in maintaining the design of the radio wave transmission cover 20, the width of the heating wire 31 can be increased.

The radio wave transmission cover 20 of the above embodiment can be applied to a vehicle provided with a radio wave radar device that emits radio waves toward the rear of the vehicle at the rear of the vehicle. In this case, the radio wave transmission cover 20 may be disposed in the propagation path of radio waves on the vehicle rear side of the radio wave radar device.

The radio wave transmission cover 20 according to the above-described embodiment is not limited to one functioning as an emblem, but is also applicable to a cover member that covers the outer side of the radio wave radar device.
The radio wave transmission cover 20 of the above embodiment can be applied to a vehicle equipped with a radio wave radar device that radiates microwaves.

DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Radio wave radar apparatus, 12 ... Switch, 13 ... Storage battery, 20 ... Radio wave transmission cover, 21 ... Radio wave transmission part, 22 ... Heat generation sheet, 23 ... Inner surface coating board, 24 ... Coating layer, 25 ... Metal film Layers 26: outer surface coating plate 31: heating wire 31A: heating wire portion 32, 33: connection terminal 34, 35: film.

Claims

In the radio wave transmission cover configured such that the heating wire is integrally provided and disposed in the radio wave path of the radio wave radar device,
In the radio wave transmission part through which the radio wave passes, a plurality of heat ray parts forming a part of the heating wire are disposed at an interval,
A radio wave transmission cover characterized in that at least a part of the plurality of heat wire portions extend in a regular pattern in which the bending directions are alternately switched toward one side in the extending direction of the heat wire portions.
The radio wave transmission cover according to claim 1, wherein all the portions of the plurality of heat ray portions extend in the regular pattern.
The radio wave transmission cover according to claim 1 or 2, wherein the regular pattern consists only of curves.
The radio wave transmission cover is an exterior component that forms an outer wall portion and a design portion of a vehicle at a portion far from the radio wave radar device.
The radio wave transmission cover according to any one of claims 1 to 3, wherein the heating wire is provided in the far part.