JP7837659B2 - Radio wave absorbing shield - Google Patents

Description

This invention relates to a radio wave absorbing shield that is fixed to a vehicle.

Vehicles equipped with radar for side-impact prevention and other purposes are fitted with radio wave absorbing shields to improve radar recognition accuracy by enhancing radar directivity and removing or reducing unwanted radio wave components. Patent Document 1 describes a radio wave absorber in which the content ratio of magnetic powder and carbon components is optimized to enhance radar directivity and remove or reduce unwanted radio wave components.

International Publication No. 2020/230708

Radio wave absorbing shields, when fixed to a vehicle, eliminate or reduce unwanted radio waves. However, because radio wave absorbing shields contain a large amount of inorganic materials such as magnetic powder, they are prone to brittleness. Therefore, when fixed to the vehicle body, vibrations during vehicle operation may cause cracks and lead to detachment.

Therefore, the object of the present invention is to provide a radio wave absorbing shield that can suppress cracking and detachment caused by vibrations during vehicle operation.

The radio wave absorbing shield of the present invention is as follows:

[1]
A radio wave absorbing shield that is fixed to a vehicle, comprising: a radio wave absorbing member containing magnetic powder that absorbs radio waves; and a fixing member that is fixed to the vehicle and houses the radio wave absorbing member.

This radio wave absorbing shield contains magnetic powder that absorbs radio waves. Therefore, it can absorb radio waves, but the radio wave absorbing material is brittle and prone to cracking and detachment. However, the stress generated in the radio wave absorbing shield due to vibrations during vehicle operation is concentrated in the fixed part that is attached to the vehicle, and the radio wave absorbing material, which is separate from the fixed part and housed within the fixed part, does not experience significant stress. Therefore, cracking and detachment due to vibrations during vehicle operation can be suppressed.

[2]
The aforementioned fixing member is a radio wave absorbing shield according to [1], which does not contain magnetic powder.

This radio wave absorbing shield does not contain magnetic powder in its fixing components, thus suppressing their brittleness. This prevents cracks and detachment even when stresses generated by vehicle vibrations concentrate on the fixing components. Furthermore, compared to systems containing magnetic powder, the amount of magnetic powder used can be reduced, resulting in cost reduction and weight reduction.

[3]
The radio wave absorbing shield according to [1] or [2], wherein the fixing member detachably accommodates the radio wave absorbing member.

In this radio wave absorbing shield, the fixing member detachably houses the radio wave absorbing member. Therefore, if the radio wave absorbing member cracks or falls off, only the radio wave absorbing member can be replaced. Conversely, if the fixing member cracks or falls off, only the fixing member can be replaced. This reduces the material costs associated with replacement.

[4]
The radio wave absorbing shield according to [3], wherein the fixing member comprises a housing space for housing the radio wave absorbing member, an insertion/removal opening for inserting and removing the radio wave absorbing member from the housing space, and a locking portion for preventing the radio wave absorbing member housed in the housing space from being removed from the insertion/removal opening.

In this radio wave absorbing shield, the fixing member has a housing space, an insertion/removal opening, and a locking mechanism. Therefore, the radio wave absorbing member can be inserted into and removed from the housing space, and the risk of the housing-equipped member falling out of the housing space can be suppressed.

[5]
The radio wave absorbing shield according to any one of [1] to [4], wherein the fixing member has a first window that exposes a part of the radio wave absorbing member.

This radio wave absorbing shield has a first window through which the fixed member exposes a portion of the radio wave absorbing member, allowing for effective absorption of radio waves through the first window.

[6]
The radio wave absorbing shield according to [5], wherein the fixing member has a second window located on the opposite side of the first window from the radio wave absorbing member and exposing a part of the radio wave absorbing member.

This radio wave absorbing shield has a second window located on the opposite side of the first window from the radio wave absorbing member, exposing a portion of the member. Therefore, even if the fixing member is made of a metal that reflects radio waves, it can still properly absorb them without reflecting them through the first window.

According to this invention, it is possible to suppress cracking and detachment caused by vibrations during vehicle operation.

This is a front view showing a radio wave absorbing shield according to an embodiment. This is a cross-sectional view along the line II-II shown in Figure 1. This is a schematic diagram showing a magnified portion of a radio wave absorbing material. This is a cross-sectional view showing a fixing member. This is a front view showing the state in which the radio wave absorbing member is being attached to and detached from the fixed member. This is a cross-sectional view showing a modified example of a radio wave absorbing shield. This is a cross-sectional view showing a modified example of a radio wave absorbing shield.

The embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, identical or equivalent elements will be denoted by the same reference numerals, and redundant descriptions will be omitted.

Figure 1 is a front view showing a radio wave absorbing shield according to this embodiment. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. As shown in Figures 1 and 2, the radio wave absorbing shield 1 according to this embodiment is attached to a vehicle 2. The radio wave absorbing shield 1 absorbs received radio waves in order to enhance the directivity of a radar (not shown) mounted on the vehicle 2 and to remove or reduce unwanted radio wave components. The radio wave absorbing shield 1 comprises a radio wave absorbing member 3 and a fixing member 4. The radio wave absorbing member 3 and the fixing member 4 are composed of separate members (separate parts) that are separable from each other.

Figure 3 is a schematic diagram showing an enlarged portion of the radio wave absorbing member. As shown in Figures 1 to 3, the radio wave absorbing member 3 is a member that absorbs radio waves. The radio wave absorbing member 3 includes magnetic powder 5 and a binder 6. In other words, the radio wave absorbing member 3 has a structure in which the magnetic powder 5 is filled into the binder 6. The magnetic powder 5 is an inorganic radio wave absorbing material. The material of the magnetic powder 5 is not particularly limited, but for example, it can be an inorganic magnetic material such as ferrite. Therefore, although the radio wave absorbing member 3 has the function of absorbing radio waves, it is also brittle and prone to cracking and detachment. The binder 6 is not particularly limited, but for example, it can be a resin, a carbon component, etc. The binder 6 may be composed of one type of material or multiple types of materials.

Figure 4 is a cross-sectional view showing the fixing member. As shown in Figures 1, 2, and 4, the fixing member 4 is fixed to the vehicle 2 and houses the radio wave absorbing member 3. In other words, in the radio wave absorbing shield 1, the fixing member 4 is fixed to the vehicle 2, but the radio wave absorbing member 3 is not fixed to the vehicle 2. When the fixing member 4 is fixed to the vehicle 2, the stress generated in the radio wave absorbing shield 1 due to vibrations during vehicle operation is concentrated in the fixing member 4 that fixes the radio wave absorbing shield 1 to the vehicle 2. Therefore, it is preferable that the fixing member 4 is made of a material that can withstand vibrations during vehicle operation. Specifically, it is preferable that the fixing member 4 is made of a material that is less prone to cracking or detachment due to vibrations during vehicle operation. If the fixing member 4 contains a large amount of inorganic material such as magnetic powder 5, the fixing member 4 becomes brittle and more susceptible to cracking and detachment. Therefore, to prevent cracking or detachment of the fixing member 4 due to vibrations during vehicle operation, it is preferable that the fixing member 4 does not contain magnetic powder. The material of the fixing member 4 can be, for example, a resin such as polypropylene (PP) or a metal such as iron.

The fixing member 4 has a fixing portion 41 that is fixed to the vehicle 2 and a housing portion 42 that houses the radio wave absorbing member 3. The fixing portion 41 and the housing portion 42 only need to be functionally separated; they do not need to be clearly separated.

The method of fixing the fixing part 41 to the vehicle 2 is not particularly limited and can be, for example, bolting or welding. The drawing shows, as an example, a case where the fixing part 41 is bolted to the vehicle 2. When the fixing part 41 is bolted to the vehicle 2, the fixing part 41 has, for example, bolt holes 43 into which bolts 7 for fixing the fixing part 41 to the vehicle 2 are inserted.

The housing section 42 detachably houses the radio wave absorbing member 3. Figure 5 is a front view showing the state in which the radio wave absorbing member is attached to and detached from the fixing member. As shown in Figures 1, 2, 4, and 5, the housing section 42 has a housing space 44, an insertion/removal opening 45, a locking part 46, a first window 47, and a second window 48.

The housing space 44 is a space for housing the radio wave absorbing member 3. The housing space 44 is formed, for example, to be substantially identical in shape to the outer form of the radio wave absorbing member 3.

The insertion/removal opening 45 is an opening that allows the radio wave absorbing member 3 to be inserted into and removed from the housing space 44. The insertion/removal opening 45 communicates with the housing space 44, exposing the housing space 44 to the outside of the radio wave absorbing shield 1. The shape of the opening of the insertion/removal opening 45 is formed to be substantially identical to the outer shape of the radio wave absorbing member 3 in a direction perpendicular to the insertion/removal direction D of the radio wave absorbing member 3 relative to the housing space 44.

The locking portion 46 prevents the radio wave absorbing member 3 housed in the housing space 44 from being removed from the insertion/removal opening 45. The state in which the locking portion 46 prevents the radio wave absorbing member 3 housed in the housing space 44 from being removed from the insertion/removal opening 45 is called the locked state. The locking portion 46 is formed, for example, in the shape of a claw that locks the radio wave absorbing member 3 housed in the housing space 44 from the insertion/removal opening 45 side. By deforming or moving the locking portion 46, the radio wave absorbing member 3 can be inserted into the housing space 44 from the insertion/removal opening 45, and the locked state can be released to remove the radio wave absorbing member 3 housed in the housing space 44 from the insertion/removal opening 45. For example, if the locking portion 46 is formed in the claw shape described above, the radio wave absorbing member 3 can be inserted into the housing space 44 from the insertion/removal opening 45 by strongly pushing the radio wave absorbing member 3 from the insertion/removal opening 45 towards the housing space 44 and pushing the locking portion 46 down towards the housing space 44. On the other hand, by firmly pushing the radio wave absorbing member 3 housed in the housing space 44 toward the insertion/removal opening 45 and tilting the locking portion 46 toward the insertion/removal opening 45, the lock state can be released and the radio wave absorbing member 3 housed in the housing space 44 can be removed from the insertion/removal opening 45.

The first window 47 is an opening that exposes a portion of the radio wave absorbing member 3. In other words, the first window 47 is an opening that prevents the insertion and removal of the radio wave absorbing member 3 from the housing space 44, while exposing the housing space 44 and the radio wave absorbing member 3 housed within it to the outside of the radio wave absorbing shield 1.

The second window 48 is located on the opposite side of the first window 47 from the radio wave absorbing member 3. In other words, the first window 47 and the second window 48 are located on the front and back sides of the housing space 44 and the radio wave absorbing member 3 housed within the housing space 44. Similar to the first window 47, the second window 48 is an opening that exposes a portion of the radio wave absorbing member 3 housed within the housing space 44. That is, the second window 48 is an opening that prevents the insertion and removal of the radio wave absorbing member 3 from the housing space 44 while exposing the housing space 44 and the radio wave absorbing member 3 housed within the housing space 44 to the outside of the radio wave absorbing shield 1.

As described above, in the radio wave absorbing shield 1 according to this embodiment, the radio wave absorbing member 3 includes magnetic powder 5 that absorbs radio waves. Therefore, the radio wave absorbing member 3 can absorb radio waves, but the radio wave absorbing member 3 is brittle and prone to cracking and detachment. However, the stress generated in the radio wave absorbing shield 1 due to vibrations during vehicle operation is concentrated in the fixing member 4 fixed to the vehicle 2, and the radio wave absorbing member 3, which is separate from the fixing member 4 and housed within the fixing member 4, does not experience significant stress. Therefore, cracking and detachment due to vibrations during vehicle operation can be suppressed.

Furthermore, in this radio wave absorbing shield 1, since the fixing member 4 does not contain magnetic powder, it is possible to suppress the brittleness of the fixing member 4. This prevents cracks and detachment of the fixing member 4 even when stress generated by vibrations during vehicle operation is concentrated on it. Moreover, compared to cases where the fixing member 4 contains magnetic powder, the amount of magnetic powder used can be reduced, thus reducing costs and weight.

Furthermore, in this radio wave absorbing shield 1, the fixing member 4 detachably houses the radio wave absorbing member 3. Therefore, if the radio wave absorbing member 3 cracks or falls off, only the radio wave absorbing member 3 can be replaced. Conversely, if the fixing member 4 cracks or falls off, only the fixing member 4 can be replaced. This reduces the material costs associated with replacement.

Furthermore, in this radio wave absorbing shield 1, since the fixing member 4 has a housing space 44, an insertion/removal opening 45, and a locking portion 46, the radio wave absorbing member 3 can be inserted into and removed from the housing space 44, and the radio wave absorbing member 3 housed in the housing space 44 can be prevented from falling out of the housing space 44.

Furthermore, in this radio wave absorbing shield 1, the fixing member 4 has a first window 47 that exposes a portion of the radio wave absorbing member 3, allowing for appropriate absorption of radio waves through the first window 47.

Furthermore, since this radio wave absorbing shield 1 has a second window 48 located on the opposite side of the first window 47 from the radio wave absorbing member 3, exposing a portion of the radio wave absorbing member 3, even if, for example, the fixing member 4 is made of a metal that reflects radio waves, it can properly absorb radio waves without reflecting them from the first window 47.

Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. It may be modified or applied to other embodiments without altering the gist of each claim.

For example, although the above embodiment was described as having a first window and a second window, it may also be possible to omit the second window, or to omit both the first and second windows. Figure 6 is a cross-sectional view showing a modified radio wave absorbing shield. In the radio wave absorbing shield 1A shown in Figure 6, the housing portion 42A of the fixing member 4A has a housing space 44, an insertion/removal opening 45, a locking portion 46, and a first window 47. In other words, the housing portion 42A of the radio wave absorbing shield 1A does not have the second window 48 of the above embodiment.

Furthermore, although the above embodiment described the fixing member as detachably housing the radio wave absorbing member, the fixing member may also detachably housing the radio wave absorbing member. Figure 7 is a cross-sectional view showing a modified radio wave absorbing shield. In the radio wave absorbing shield 1B shown in Figure 7, the housing portion 42B of the fixing member 4B has a housing space 44, a first window 47, and a second window 48. In other words, the housing portion 42B of the radio wave absorbing shield 1B does not have the insertion/removal opening 45 and locking portion 46 of the above embodiment. In the radio wave absorbing shield 1B, for example, an opening corresponding to the insertion/removal opening can be formed in the housing space 44, and after housing the radio wave absorbing member 3 in the housing space 44, the opening corresponding to the insertion/removal opening can be sealed, thereby making the fixing member 41B detachably housing the radio wave absorbing member 3.

1...Radio wave absorbing shield, 1A...Radio wave absorbing shield, 1B...Radio wave absorbing shield, 2...Vehicle, 3...Radio wave absorbing member, 4...Fixing member, 4A...Fixing member, 4B...Fixing member, 5...Magnetic powder, 6...Binder, 7...Bolt, 41...Fixing part, 42...Housing part, 42A...Housing part, 42B...Housing part, 43...Bolt hole, 44...Housing space, 45...Insertion/removal opening, 46...Locking part, 47...First window, 48...Second window.

Claims (5)

A radio wave absorbing shield that is fixed to a vehicle,
A radio wave absorbing member containing magnetic powder that absorbs radio waves,
The vehicle comprises a fixing member that is fixed to the vehicle and houses the radio wave absorbing member,
The aforementioned fixing member does not contain magnetic powder.
Radio wave absorbing shield. A radio wave absorbing shield that is fixed to a vehicle,
A radio wave absorbing member containing magnetic powder that absorbs radio waves,
The vehicle comprises a fixing member that is fixed to the vehicle and houses the radio wave absorbing member,
The fixing member detachably houses the radio wave absorbing member.
Radio wave absorbing shield. The aforementioned fixing member is
A housing space for housing the aforementioned radio wave absorbing member,
The aforementioned housing space has an insertion/removal opening from which the radio wave absorbing member can be inserted and removed,
The device includes a locking mechanism that prevents the radio wave absorbing member housed in the aforementioned housing space from being removed from the insertion/removal opening.
The radio wave absorbing shield according to claim 2 . A radio wave absorbing shield that is fixed to a vehicle,
A radio wave absorbing member containing magnetic powder that absorbs radio waves,
The vehicle comprises a fixing member that is fixed to the vehicle and houses the radio wave absorbing member,
The fixing member has a first window that exposes a part of the radio wave absorbing member.
Radio wave absorbing shield. The fixing member has a second window located on the opposite side of the first window from the radio wave absorbing member, which exposes a part of the radio wave absorbing member.
The radio wave absorbing shield according to claim 4 .