JP4466938B2 - Granular material having electromagnetic wave absorption characteristics and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides an electromagnetic wave absorption characteristic in which an electromagnetic wave absorber is efficiently arranged inside a member when manufacturing a building that prevents interference caused by an unnecessary electromagnetic wave in a place where communication, detection or measurement is performed using the electromagnetic wave. The present invention relates to a granular material and a manufacturing method thereof.
[0002]
[Prior art]
Development of an automatic toll collection system (ETC) for toll roads and a driving support system (AHS) for cars traveling on roads is advancing as part of the intelligent traffic system (ITS), which is the next-generation road traffic system.
[0003]
This automatic toll collection system is installed in the automatic fee payment device (IC card, radio wave tag, etc.) installed in the car and the toll gate of the toll gate without stopping the traffic of cars traveling on toll roads such as expressways. This is a system that collects fees by wireless communication with the automatic fee collection device. This automatic toll collection system is expected to be introduced not only from the standpoint of fee payment, but also from the viewpoint of alleviating traffic congestion and reducing labor costs.
[0004]
In the automatic toll collection system, detection means such as a radar of an automatic toll collection device arranged at the toll gate detects that a car traveling on the road has approached the toll gate to a predetermined distance.
[0005]
Then, the wireless communication device of the automatic toll collection device sends a signal to the running vehicle, and the information necessary for determining the toll for the vehicle from the automatic toll payment device mounted on the vehicle (vehicle type, contract details, payment account, etc.) ) Is transmitted by wireless communication. Then, the automobile-side automatic fee payment device transmits information necessary for determining the toll of the vehicle to the wireless communication device of the automatic fee collection device.
[0006]
The automatic toll collection device that has received the information necessary for determining the toll of the automobile calculates the toll based on the travel distance of the automobile on the toll road and executes a toll collection process.
[0007]
Also, in the automobile driving support system, for example, a lane marker is installed at each predetermined position on the road along the driving lane of the automobile, and detection of a radar or the like of the driving support apparatus mounted on the automobile traveling on the road is performed. The device detects the position of the lane marker to detect the proper travel route, and automatically drives the vehicle steering system to warn the driver of the possibility of deviation from the travel lane in order to drive the vehicle along this proper travel route. Intervene to help drive safely. In addition, various communications are performed between the lane marker communication device arranged on the road and the vehicle, which is used for the determination of the travel route and provided for transportation.
[0008]
[Problems to be solved by the invention]
In the automatic toll collection system and the driving support system for automobiles in the intelligent transportation system as described above, a traveling automobile is targeted for communication, detection or measurement using electromagnetic waves of a relatively high frequency. For this reason, the operation of communicating, detecting, or measuring using a relatively high frequency electromagnetic wave must be executed accurately at the instant when the traveling vehicle passes through a predetermined place.
[0009]
However, in this automatic toll collection system or automobile driving support system, unnecessary scattered electromagnetic waves are generated when a relatively high frequency electromagnetic wave emitted from these systems radiates on a road or the like. And this unnecessary scattered electromagnetic wave is received by the receiver of the automatic toll collection system or the driving support system of the automobile, and there is a possibility that an error occurs in the operation of communication, detection or measurement.
[0010]
In such an automatic toll collection system or a driving support system for automobiles, vehicles traveling in the field are targeted, so the automatic toll collection system or driving support system for cars must be installed in an open field. Therefore, in this automatic toll collection system or automobile driving support system, unnecessary scattered electromagnetic waves that surround the automatic toll collection system or automobile driving support system with an electromagnetic wave reflector, as are commonly used electromagnetic wave interference countermeasure means. It is not possible to take measures for shielding.
[0011]
Therefore, by constructing buildings such as roads and toll gates with electromagnetic wave absorbing materials that have the function of absorbing electromagnetic waves using internal loss of members, electromagnetic waves emitted from these systems can be efficiently absorbed. It has been proposed to prevent unnecessary generation of scattered electromagnetic waves.
[0012]
Therefore, it is conceivable to manufacture and use an electromagnetic wave absorbing material with a material mixed with ferrite, which is a magnetic material. However, although ferrite is a material having excellent absorption characteristics, the ferrite member can cope with the frequency band of the electromagnetic wave to be absorbed. The thickness will be adjusted. For this reason, the electromagnetic wave absorbing material has drawbacks that it is difficult to use as a building material, for example, the weight of ferrite mixed therein increases and the weight of the electromagnetic wave absorbing material itself increases.
[0013]
It is also conceivable to manufacture or construct an electromagnetic wave absorbing material by mixing a relatively light short fibrous dielectric material or the like into the construction material. In this case, the electromagnetic wave absorbing material needs to be arranged with a short fibrous dielectric material inside thereof in an average and appropriate distribution state.
[0014]
For example, when manufacturing such an electromagnetic wave absorbing material, if a short fibrous dielectric material is mixed well with the aggregate and the binder and not spread all over the corner, it has sufficient electromagnetic wave absorption characteristics and quality. Therefore, there is a problem that much labor is required for the manufacturing or construction work.
[0015]
In consideration of the above-mentioned fact, the present invention has an electromagnetic wave absorption characteristic for easily manufacturing an electromagnetic wave absorbing material having a stable quality by arranging an electromagnetic wave absorber in an average and appropriate distribution state inside. An object is to newly provide a granular material and a manufacturing method thereof.
[0016]
[Means for Solving the Problems]
  The particulate material having electromagnetic wave absorption characteristics according to claim 1 of the present invention is solidified by adhering to a lump of nuclei and around the nuclei.A bubble-like space is formedAnd an electromagnetic wave absorber that absorbs electromagnetic waves that are uniformly dispersed and mixed in the base material.
[0017]
  By configuring as described above, since the electromagnetic wave absorber is dispersed and arranged around the core inside the granular material, the granular material has stable electromagnetic wave absorption characteristics and stable electromagnetic wave absorption characteristics. Can be obtained. Further, the granular material having the electromagnetic wave absorption characteristics has a function of absorbing electromagnetic waves satisfactorily. Furthermore, if the layer of the mixture of the base material and the electromagnetic wave absorber is formed around the core with a substantially uniform thickness, the outer shape and size of the granular material can be made uniform.
  Moreover, since the bubble-shaped space is formed in the base material, weight reduction of its own weight can be achieved.
[0018]
  A granular material having electromagnetic wave absorption characteristics according to claim 2 of the present inventionIs a lump of nuclei, an electromagnetic wave absorber arranged outside the nucleus in a layered manner that encloses the nucleus, and arranged outside the nucleus in a layered shape enclosing the nucleus, forming a bubble-like space An electromagnetic wave absorber layer, and the base material layer form a laminated structure.It is characterized by that.
[0019]
  By configuring as described above, the electromagnetic wave absorber is disposed in a layered manner around the core and then dispersed in the vicinity thereof, so that the electromagnetic wave absorber can be dispersed on the whole outside of the core on average. . Thereby, the property of absorbing the electromagnetic wave of the granular material can be made more uniform at each part of the outer periphery of the granular material, the electromagnetic wave absorption characteristics of the granular material can be stabilized, and the reliability can be further improved.
  Moreover, since the bubble-shaped space is formed in the base material, weight reduction of its own weight can be achieved.
[0020]
According to a third aspect of the present invention, there is provided a method for producing a granular material having electromagnetic wave absorption characteristics. In the base material, an electromagnetic wave absorber that absorbs electromagnetic waves and a foam material are uniformly dispersed and mixed. The process of adhering to the periphery of the nucleus, and baking in a state where the mixture of the base material and the electromagnetic wave absorber is attached to the periphery of the core, integrally in a state where it is foamed in the part including the base material And a solidifying step.
[0021]
According to the manufacturing method as described above, it is possible to easily manufacture a granular material in which an electromagnetic wave absorber is dispersed in an average in a base material solidified integrally in a state of being foamed around the core. Furthermore, the outer shape and size of the granular material can be made uniform. Electromagnetic wave absorbers placed on the side walls between the gaps inside the granular material with electromagnetic wave absorption characteristics are dispersed and arranged on the average corresponding to the surfaces that partition the gaps, thus absorbing electromagnetic waves well. it can.
[0026]
  Claims of the invention4The method for producing a granular material having electromagnetic wave absorption characteristics described in 1) includes a step of attaching an electromagnetic wave absorber that absorbs electromagnetic waves to the outside of a lump nucleus, and a base material and a foam material or a material containing these on the outside of the nucleus. In the state of foaming in the part including the base material by firing the state in which the electromagnetic wave absorber and the base material and the foam material or the material containing these are laminated on the outside of the core And a step of solidifying integrally.
[0027]
According to the manufacturing method as described above, the electromagnetic wave absorber is disposed on the side wall portion between the voids in the base material integrally solidified in a foamed state around the core, and corresponds to the surface partitioning the void portion. Therefore, electromagnetic waves can be absorbed well. Therefore, a granular material having electromagnetic wave absorption characteristics can be mass-produced with stable quality.
[0028]
  Claim5The invention described in claim 1 or claim 22The granular material having the electromagnetic wave absorption characteristics described in 1) is characterized in that the electromagnetic wave absorber is carbon fiber.
[0029]
By configuring as described above, the design can be changed so that the required electromagnetic wave absorption characteristics can be obtained simply by changing and adjusting the length of the carbon fiber corresponding to the wavelength of the electromagnetic wave to be absorbed. Even when the wavelength of the electromagnetic wave becomes different, it can be handled without changing the weight of the granular material using the carbon fiber.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, a granular material having electromagnetic wave absorption characteristics of the present invention and an embodiment relating to a manufacturing method thereof will be described with reference to FIGS.9, FIG. 11 and FIG.Will be explained. FIG. 1 is a perspective view showing a schematic configuration of an automatic toll collection station on a toll road as a structure constructed using a granular material having electromagnetic wave absorption characteristics according to an embodiment of the present invention.
[0031]
In this automatic toll collection station, each automatic toll collection device 12 is arranged in a toll gate 10 installed at a predetermined place on a toll road corresponding to each travel lane on the toll road.
[0032]
The automatic toll collection device 12 includes a vehicle detection radar and a wireless communication device. In this automatic toll collection device 12, a radar millimeter wave is emitted from the vehicle detection radar to a predetermined range on the front side of the toll gate 10, and the vehicle 14 has arrived at a predetermined position on the front side of the toll gate 10. It is configured to detect.
[0033]
Further, when the automatic toll collection device 12 detects that the vehicle 14 has arrived at a predetermined position on the road lane by the vehicle detection radar, the automatic toll collection device 12 emits a communication signal MW from the wireless communication device of the automatic toll collection device 12. Then, a signal is transmitted to the traveling vehicle 14.
[0034]
The vehicle 14 is equipped with an automatic fee payment device (not shown), and this automatic fee payment device receives the communication signal MW from the wireless communication device of the automatic fee collection device 12. Then, the automatic toll payment device transmits information (vehicle type, weight, model, registration number, etc.) necessary for collecting the toll for the vehicle 14 by wireless communication.
[0035]
The automatic toll collection device of the automatic toll collection device 12 that has received the information necessary for determining the toll of the vehicle 14 calculates the fee based on the travel distance of the car on the toll road and executes the toll collection processing. To do.
[0036]
In the automatic toll collection station described above, at least a predetermined range in which a communication signal MW, for example, a radio wave of a frequency band of 5.80 GHz emitted from a wireless communication device of the automatic toll collection device 12 is emitted, and an automatic fee is collected. It has a characteristic of absorbing a low-intensity electromagnetic wave for communication, detection, or measurement over a road or a building part over a predetermined range irradiated with millimeter waves emitted from a vehicle detection radar of the toll device 12. It is constructed with an electromagnetic wave absorbing material manufactured using a granular material having electromagnetic wave absorbing characteristics.
[0037]
This prevents the operation of wireless communication or vehicle detection from being disturbed by electromagnetic interference due to electromagnetic interference caused by radio waves that are unnecessarily reflected on the road surface or buildings, thereby preventing troubles in operations such as toll collection.
[0038]
For this reason, a road with a pavement structure having a function of absorbing low-intensity electromagnetic waves for communication, detection or measurement is configured as shown in FIG. 2 or FIG.
[0039]
The road shown in FIG. 2 comprises a protective layer 16 at the most surface portion of the road, a surface layer 18 is provided below it, an electromagnetic wave reflection layer 20 is provided below it, and a lower structure is further provided below it. 22 is provided.
[0040]
The protective layer 16 is formed on the outermost surface of the road, and is configured to protect the surface layer 18 from impacts and wear caused by traffic of vehicles. In this way, by providing the protective layer 16 on the surface of the surface layer 18 on the road, the radio wave absorption performance on the surface layer 18 due to changes in the surface state and thickness of the surface layer 18 due to excessive wear and impact due to traffic of people and automobiles. It is possible to prevent a decrease in the above.
[0041]
The protective layer 16 suppresses reflection of electromagnetic waves on the surface thereof and facilitates incidence of electromagnetic waves. For example, a material having an electrical characteristic intermediate between air such as normal asphalt and the surface layer 18, Or it is comprised with the asphalt which has the electrical property close | similar to air rather than the surface layer 18. FIG. In addition, it is desirable that the protective layer 16 has a large gap in order to facilitate the incidence of electromagnetic waves.
[0042]
The surface layer 18 as a structure disposed on the road having the electromagnetic wave absorbing function is composed of a base material (asphalt, cement, concrete, etc.) such as an aggregate and a binder, and a conductive wave absorbing material or a magnetic wave absorbing material alone. Or it is comprised with the electromagnetic wave absorption material which has the electromagnetic wave absorption function (energy attenuation) mixed and mixed.
[0043]
The conductive electromagnetic wave absorbing material, which is a dielectric material used here, is preferably a highly durable metal material such as a carbon material or stainless steel, and these materials are used in the form of fibers, beads, powders, or the like. .
[0044]
Moreover, as magnetic materials, such as a magnetic wave absorption material used here, a ferrite, a permalloy, etc. are used for a granular form, a powder form, a linear form, a plate form, for example.
[0045]
Furthermore, the electromagnetic characteristics of the surface layer 18 can be adjusted by increasing or decreasing the amount of voids, the type of aggregate used (especially specific gravity), and the like. Usually, the dielectric constant can be reduced by increasing the amount of voids. .
[0046]
Next, the surface layer 18 is made of an electromagnetic wave absorber as a conductive electromagnetic wave absorbing material (conductive fiber such as carbon fiber as an electromagnetic wave absorber, that is, an electromagnetic wave that absorbs incident electromagnetic waves and causes resistance loss. Explains the case of using an electromagnetic wave absorbing material using a granular material having an electromagnetic wave absorption characteristic to which a so-called Joule heat loss property that converts to heat and a material that causes an energy loss due to an induced current are added) To do.
[0047]
The electromagnetic wave absorber added to the granular material for constituting the surface layer 18 uses carbon fiber 24 (carbon fiber) which is a conductive fiber, metal fiber such as carbon-containing fiber, needle carbon, stainless steel, or the like. You may do it. In particular, when carbon fiber is used, it has high environmental resistance and durability, so that it can be prevented from being affected by the climate such as rainfall and snowfall.
[0048]
Next, the length of the carbon fiber 24 when the carbon fiber 24 that is an electromagnetic wave absorber is added to the granular material for forming the surface layer 18 will be described.
[0049]
First, in order to expect a resistance loss when an electromagnetic wave is incident on the resistance loss body, the length (L) of the resistance loss body with respect to the wavelength λ of the electromagnetic wave to be absorbed (in a vacuum) is: It is preferable that L = nλ / 2 (n is a natural number).
[0050]
Secondly, the electromagnetic wave becomes shorter than the wavelength in the air due to the wavelength shortening effect due to the electrical properties such as the permittivity of the substance, medium, and resistance loss body (in this case, the carbon fiber 24) itself. In consideration of this point, the shortest length of the resistive loss body actually mixed (Lr) is calculated on the theoretical formula and confirmed by experiments, and the shortest length of the resistive loss body actually mixed ( Lr) was found to have an effective resistance loss effect (electromagnetic wave absorption effect) when Lr ≧ λ / 10.
[0051]
Next, the maximum length of the carbon fiber 24 as a resistance loss body added to the granular material constituting the surface layer 18 will be described. Factors that define the length (Lrmax) of the resistance loss body to be actually mixed include the following.
[0052]
First, if the fiber length is too long compared to the granular material to which the carbon fiber 24 is added, it becomes difficult to hold the carbon fiber 24 along the outer peripheral surface portion of the granular material.
[0053]
Second, the surface layer 18 usually has a single construction thickness of 30 to 50 mm. Therefore, if the length of the carbon fiber 24 to be mixed is longer than the thickness of a single construction, the fibers are likely to be unevenly distributed in the surface layer portion after construction.
[0054]
From the above reasons and experimental results, it is possible to obtain good results when the maximum size of the carbon fiber 24 is set to 50 mm or less so that the electromagnetic wave absorption characteristic is approximately −10 to −15 dB (local conditions) at 5.8 GHz. I understood.
[0055]
Next, the length condition of the carbon fiber 24 that can absorb the electromagnetic wave of the predetermined wavelength λ which is the absorption target most efficiently, as the resistance loss body added to the granular material constituting the surface layer 18 will be described. The carbon fiber 24 absorbs the electromagnetic wave having the predetermined wavelength λ most efficiently when the length of the carbon fiber 24 becomes a length resonating with the electromagnetic wave having the predetermined wavelength λ.
[0056]
That is, the length of the carbon fiber 24 is a length that is a natural number multiple of approximately λ / 2 with respect to an electromagnetic wave with a predetermined wavelength λ that is used for communication, detection, or measurement. Note that the carbon fiber 24 may be formed in a short linear shape so that the length is λ / 2n (n is a natural number).
[0057]
Here, the wavelength of the electromagnetic wave used for communication, detection or measurement is shortened by the wavelength shortening effect due to the electrical characteristics such as the inherent dielectric constant when entering the protective layer 16 and the surface layer 18. Furthermore, the wavelength of the electromagnetic wave used for this communication, detection or measurement is shortened by the wavelength shortening effect due to the electrical characteristics such as the dielectric constant when entering the carbon fiber 24 mixed in the surface layer 18.
[0058]
Therefore, in order to set the length of the carbon fiber 24 mixed in the surface layer 18 to a length that resonates with the electromagnetic wave having the predetermined wavelength λ, the electrical characteristics such as the specific dielectric constant for the protective layer 16, the surface layer 18, and the carbon fiber 24. Considering the wavelength shortening effect by.
[0059]
When the length of the carbon fiber 24 is set to a resonating length, for example, the wavelength expected to be shortened by the wavelength shortening effect of the electromagnetic wave from the electrical characteristics such as the dielectric constant of the material constituting the general surface layer 18. Further, the wavelength expected to be shortened by the wavelength shortening effect of the electromagnetic wave from the electrical characteristics such as the dielectric constant of the carbon fiber 24 is calculated, and the wavelength of the electromagnetic wave shortened under actual conditions is predicted.
[0060]
Next, carbon fibers 24 are prepared in which the length is changed little by little near the predicted length of resonance of the carbon fibers 24, and samples mixed in the surface layer 18 are prepared for each of these different lengths.
[0061]
And the electromagnetic wave of predetermined wavelength (lambda) used for communication, a detection, or a measurement is irradiated, and the absorption characteristic is calculated | required. At this time, the length of the carbon fiber 24 from which the peak effect of the absorption characteristic is obtained is set as the length of the carbon fiber 24 that resonates with an electromagnetic wave having a predetermined wavelength λ used for communication, detection, or measurement.
[0062]
Thus, when the carbon fiber 24 has a length that resonates with respect to the electromagnetic wave having the predetermined wavelength λ, the surface layer 18 efficiently absorbs the electromagnetic wave having the predetermined wavelength λ used for communication, detection, or measurement. Therefore, it is possible to effectively prevent the electromagnetic interference of the unnecessary electromagnetic wave due to the reflection of the electromagnetic wave having the predetermined wavelength λ, and the operation of communication, detection or measurement can be performed reliably.
[0063]
Next, the optimal addition amount of the carbon fiber 24 as a resistance loss body added to the granular material as the electromagnetic wave absorbing material for constituting the surface layer 18 will be described.
[0064]
When the amount of carbon fiber 24 added to the granular material of the base material is increased, the amount of reflection of the electromagnetic wave in the base material increases, and eventually becomes a reflector of the electromagnetic wave. Experimentally, a base material having asphalt: aggregate = 5: 95 (weight ratio) was used, and carbon fiber 24 (5 mm in length) added thereto was 0.5% (weight) of the granular material. In the case where only the ratio is added, the result that the reflection amount increases is obtained.
[0065]
Therefore, the suitability as an electromagnetic wave absorbing material having an electromagnetic wave absorbing function (energy attenuation) is preferably set so that the carbon fiber 24 mixed in the base material is 0.5% (weight ratio) or less of the granular material as the aggregate. I think.
[0066]
As shown in FIG. 2, the electromagnetic wave reflection layer 20 disposed on the road having an electromagnetic wave absorbing function is formed using a conductive wave absorbing material made of carbon fiber, metal fiber, or the like. For example, a mesh formed of these materials (mesh size: preferably 1/20 or less with respect to the wavelength of the target electromagnetic wave) is placed on the surface of the base layer in the lower structure 22 behind the surface layer 18.
[0067]
The electromagnetic wave reflection layer 20 may be disposed in the base layer, or a conductive wave absorbing material may be sufficiently mixed into the surface portion or the whole of the base layer to constitute a reflection layer. Alternatively, the amount of carbon fiber 24 added to the granular material of the base material may be sufficiently increased to constitute an electromagnetic wave reflector, which is arranged on the surface of the base layer in the lower structure 22 without any gaps, and may be configured as a reflective layer. good.
[0068]
The lower structure 22 is a conventional pavement structure such as general sand or gravel.
[0069]
Next, in the road having the electromagnetic wave absorption function shown in FIG. 2 described above, the reflected electromagnetic wave IW1 reflected from the upper surface of the surface layer 18, and the reflected electromagnetic wave OW1 incident on the surface layer 18 and reflected by the electromagnetic wave reflection layer 20 and transmitted through the surface layer 18 A configuration for attenuating these electromagnetic waves with the internal loss due to the canceling action will be described.
[0070]
In order to make the reflected electromagnetic wave IW1 and the reflected electromagnetic wave OW1 have opposite phases, the thickness D of the surface layer 18 is set to D = λ (n + 1) / 4COSθ (λ is the wavelength of the electromagnetic wave to be absorbed, n is a natural number, θ May be set to the incident angle of the electromagnetic wave.
[0071]
With this configuration, the phase of the reflected electromagnetic wave OW1 that is incident on the surface layer 18 and then reflected on the electromagnetic wave reflection layer 20 and transmitted through the surface layer 18 is reversed with respect to the reflected electromagnetic wave IW1 reflected on the upper surface of the surface layer 18. The reflected electromagnetic wave IW1 and the reflected electromagnetic wave OW1 cancel each other and disappear or attenuate.
[0072]
Therefore, reflection of electromagnetic waves on the road provided with the surface layer 18 can be reduced.
[0073]
Further, in order to reverse the phase of the reflected electromagnetic wave OW1 at the surface layer 18, instead of setting the thickness D of the surface layer 18 to λ (n + 1) / 4COSθ, the dielectric constant of the surface layer 18 is changed to change the so-called electrical length of the surface layer 18. May be changed and adjusted to λ (n + 1) / 4COSθ.
[0074]
In order to change and adjust the electrical length to λ (n + 1) / 4COSθ by changing the dielectric constant of the surface layer 18, the pavement material of the surface layer 18 is made of bead-like carbon particles in addition to the carbon fibers 24 as shown in FIG. An appropriate amount of 26 (carbon powder may be used) is mixed.
[0075]
Thereby, the dielectric constant of the pavement material constituting the surface layer 18 is changed and adjusted, and the electric length corresponding to the thickness of the surface layer 18 is changed and adjusted to λ (n + 1) / 4COSθ, and the reflected electromagnetic wave reflected by the electromagnetic wave reflection layer 20 The phase of OW1 is reversed.
[0076]
By configuring in this way, the actual thickness of the surface layer 18 and the electrical length of the surface layer 18 can be configured differently. Therefore, in road design such as adapting the thickness of the surface layer 18 to the conditions on the strength of the road. Can increase the degree of freedom.
[0077]
Further, by configuring the road as shown in FIG. 3, in the electromagnetic wave absorbing material of the surface layer 18, the carbon fibers 24 and the carbon grains 26 combine to cause an electromagnetic induction phenomenon, and energy loss due to the induced current. The energy of the electromagnetic wave to be absorbed can be attenuated more by expanding the frequency.
[0078]
Further, the thickness of the surface layer 18 portion on the road is increased, and the electromagnetic wave incident on the surface layer 18 is attenuated and disappears on the path reflected by the electromagnetic wave reflection layer 20 and passing through the surface layer 18. You may comprise so that it may not radiate | emit.
[0079]
Alternatively, the surface layer 18 portion on the road may be enlarged to a necessary and sufficient thickness so that electromagnetic waves incident from the surface of the surface layer 18 are absorbed on a path toward the bottom surface of the surface layer 18 and disappear.
[0080]
  Next, regarding the granular material having electromagnetic wave absorption characteristics used for the production of the electromagnetic wave absorbing material, FIG. 4 to FIG.9The description will be given with reference.
[0081]
The granular material 30 having the electromagnetic wave absorption characteristics (electromagnetic wave absorption function, energy attenuation function) includes a core 36 which is a lump of solid having a predetermined size, and a base material and an electromagnetic wave absorber arranged in a layer surrounding the periphery. It is constructed by fixing and integrating.
[0082]
This core 36 is a solid (particle size) such as a mixture of coal ash powder and clay powder, molded into a predetermined shape and then fired and solidified, a block of natural stone, a block of granular material formed of cement, and the like. At least about 1 mm).
[0083]
For the base material, for example, a powder obtained by mixing coal ash with a clay (powder) granulation aid is used.
[0084]
The electromagnetic wave absorber is composed of a conductive radio wave absorbing material or a magnetic material alone or in combination.
[0085]
The conductive electromagnetic wave absorbing material used here is preferably a dielectric material and a highly durable carbon material or stainless steel, and these materials are used in the form of fibers, beads, powders, or the like.
[0086]
Moreover, as a magnetic material to be used, ferrite is used in a granular or powder form, for example.
[0087]
Electromagnetic wave absorbers absorb incident electromagnetic waves and cause resistance loss, those that have so-called Joule heat loss properties that convert electromagnetic wave energy into heat, and those that cause energy loss due to induced currents Can be configured.
[0088]
Furthermore, the electromagnetic wave absorber mixed in the granular material 30 may use carbon-containing fibers, needle carbon, metal fibers such as stainless steel, conductive fibers, and the like in addition to the carbon fibers 24 (carbon fibers). In particular, when carbon fiber is used, it has high environmental resistance and durability, so that it can be prevented from being affected by the climate such as rainfall and snowfall.
[0089]
The length, shape, added amount, etc. of the carbon fiber 24 are the same as those of the surface layer 18 shown in FIG. 2 or FIG.
[0090]
In addition, the mixing ratio of the dielectric material or magnetic material (electromagnetic wave absorber) to the base material is appropriately changed and adjusted, or the quality of the dielectric material or magnetic material (electromagnetic wave absorber) mixed in the granular material 30 is changed as desired. The granular material 30 having various electromagnetic wave absorption characteristics can be obtained.
[0091]
For example, depending on the use of the electromagnetic wave absorption characteristics, the granular material 30 having a relatively large amount of carbon fiber 24 (electromagnetic wave absorber) is configured, or the amount of carbon fiber 24 (electromagnetic wave absorber) is relatively large. The reduced granular material 30 can be constructed and used.
[0092]
In addition, when carbon fibers 24 having different lengths are mixed in the granular material 30 for each length, and these are used in appropriate combinations, the frequency bands of electromagnetic waves to be absorbed are diverse. Can respond.
[0093]
Furthermore, when the granular material 30 is configured using the carbon fiber 24 (electromagnetic wave absorber), the length of the carbon fiber 24 may be changed and adjusted in accordance with the frequency band of the electromagnetic wave to be absorbed.
[0094]
Further, the electromagnetic characteristics of the granular material 30 can be adjusted by increasing or decreasing the amount of voids provided therein. Normally, the dielectric constant can be reduced by increasing the amount of voids.
[0095]
  Next, in manufacturing the granular material 30 described above, an example is shown below.MadeIt can be manufactured by a manufacturing method.
[0096]
In the first manufacturing method of the granular material, first, the manufacturing operation of the raw material measuring step is performed. This raw material weighing process involves weighing each required weight of dielectric material or magnetic material (electromagnetic wave absorber), base material (powder of coal ash, etc.) and granulation aid (clay powder, etc.). This is a process for preparing the material. Here, when the carbon fiber 24 (electromagnetic wave absorber) is used, the length thereof is set corresponding to the size of the nucleus 36.
[0097]
In the next mixing step, the required weight of dielectric material or magnetic material prepared in the raw material measurement step, the base material, and the granulation aid are charged into the mixer and mixed uniformly.
[0098]
Next, in the adhering step of adhering the mixture of the electromagnetic wave absorber, the base material, and the granulation aid to the core, a predetermined amount of the mixture of the electromagnetic wave absorber, the base material, and the granulation aid is adhered around the core 36 in a layered manner. Let
[0099]
Next, the outer shape of a predetermined amount of a mixture of an electromagnetic wave absorber, a base material, and a granulation aid around the core 36 in the granular forming step is shown in FIG. It is formed in a predetermined shape such as a small lump having a random outer shape or a cylindrical shape as shown in FIG.
[0100]
Even when the granular material 30 is made into a small lump having a random outer shape, a layer of a mixture of the electromagnetic wave absorber, the base material, and the granulation aid is formed with a substantially uniform thickness around the core 36. Therefore, the external shape of each granular material 30 can be arranged in a substantially similar shape.
[0101]
Next, in the firing step, the core 36, dielectric material or magnetic material, base material, and granulation aid formed in a predetermined shape such as a spherical shape, a small block shape, or a cylindrical shape are baked at a predetermined temperature. By solidifying, a granular material 30 as shown in FIGS. 4 and 9 is produced.
[0102]
  Figure9As shown, the light-weight granular material 30 manufactured as described above includes an infinite number of void portions (bubble-shaped space portions) and side wall portions 30 </ b> A around the core 36.
[0103]
For this reason, in the side wall portion 30A in the granular material 30, the carbon fibers 24 are captured, and a three-dimensional structure is formed in which the carbon fibers 24 are uniformly dispersed around 36 inside the granular material 30. .
[0104]
That is, in this lightweight granular material 30, the shell-shaped side wall portion 30A is formed so as to surround the bubble-shaped space portion. Accordingly, the carbon fibers 24 dispersed in the shell-shaped side wall portion 30A are arranged so as to face in the tangential direction corresponding to the curved surface portions on the inner side of the side wall portion 30A partitioning the bubble-shaped space, and thus the carbon fibers 24 are arranged. The orientation of is not aligned in one direction.
[0105]
As a result, the carbon fibers 24 are arranged so as to be substantially averaged in all three-dimensional directions inside the shell-shaped side wall portion 30A surrounding each bubble-shaped space portion, and the shell-shaped side wall portions 30A. The carbon fibers 24 are distributed at a substantially uniform density in the inside, and the carbon fibers 24 are uniformly dispersed to form a three-dimensional structure.
[0106]
Furthermore, since the three-dimensional structure in which the carbon fibers 24 are uniformly dispersed is automatically formed in the firing step when the granular material 30 is manufactured, the carbon fibers 24 can be efficiently and easily formed inside the granular material 30. Further, the weight of the granular material 30 itself can be reduced.
[0107]
Moreover, in the first manufacturing method of the granular material 30 described above, in order to make foaming inside the granular material 30 more active, a foaming aid such as calcium carbonate or silicon carbide was mixed in the powder as the base material in the mixing step. Thereafter, a method of obtaining bubbles by firing in a firing step to generate carbon dioxide gas may be used.
[0108]
The granular material 30 may be made of a highly durable carbon material or stainless steel, and formed into a fibrous shape, a bead shape, or a granular shape as a dielectric material mixed therein.
[0109]
Further, by changing the blending ratio of the dielectric material or the magnetic material mixed with the granular material 30, the electromagnetic wave absorbing action of the granular material 30 can be set in accordance with the wavelength and the use environment.
[0110]
Furthermore, the electromagnetic wave absorption performance of the granular material 30 can be adjusted by the amount of the dielectric material mixed into the granular material 30. The material and shape (diameter and length) of the dielectric material and magnetic material are changed according to the frequency of the electromagnetic wave to be absorbed. Further, the absorption characteristics can be changed by changing the particle size (shape) of the granular material 30 itself.
[0111]
In addition, the particle size and external shape of the granular material 30 can be freely set.
[0112]
  Next, as a reference example,Producing the granular material 30 described aboveFirst2. Manufacturing methodWill be described.
[0113]
In the second manufacturing method, powder and fiber material are alternately attached to the outside of the core 36 and granulated to a required size.
[0114]
For this reason, in the second production method, first, the core 36, the electromagnetic wave absorber (carbon fiber 24 is used here), the base material (powder such as coal ash), and the granulation aid (clay powder etc.) ) Are prepared separately.
[0115]
Next, in the attaching step, as a first operation, as shown in FIG. 13, the carbon fiber 24 as the electromagnetic wave absorber is uniformly attached to the entire outer peripheral surface of the core 36.
[0116]
At this time, a small amount of moisture or a binder material may be used so as to enhance the adhesion effect of the carbon fibers 24 to the outer peripheral surface of the core 36.
[0117]
As a result, the carbon fibers 24 are attached to the entire outer peripheral surface of the core 36, and each carbon fiber 24 is uniformly dispersed in a state of facing the tangential direction at each contact portion of the outer peripheral surface of the core 36. Therefore, the orientation of each carbon fiber 24 is not aligned in one direction.
[0118]
Next, as a second operation, as shown in FIG. 14, the base material and the granulation aid were mixed uniformly over the entire outer peripheral surface of the core 36 with the carbon fibers 24 attached to the entire outer peripheral surface. Things are deposited in layers.
[0119]
At this time, a small amount of moisture or so as to enhance the adhesion effect for adhering the mixture of the base material and the granulation aid in a layered manner on the carbon fiber 24 adhered to the outer peripheral surface of the core 36. A binder material may be used.
[0120]
Next, as a third operation, as shown in FIG. 15, the entire outer peripheral surface of the carbon fiber 24 adhered to the outside of the core 36 and coated with a mixture of a base material and a granulation aid as described above. The carbon fiber 24 as an electromagnetic wave absorber is adhered uniformly.
[0121]
Next, as shown in FIG. 16, as shown in FIG. 16, the carbon fiber 24, the mixture of the base material and the granulation aid, and three layers of the carbon fiber 24 are stacked on the outside of the core 36 in the same manner as described above. The granular material 30 is configured by adhering a mixture of a base material and a granulation aid uniformly on the entire outer peripheral surface of the adhered material in a layered manner.
[0122]
This granular material 30 is formed by alternately adhering and integrating the carbon fiber 24 layer, the base material and the granulation aid layer on the outer peripheral surface of the core 36 as described above. , Granulated to a predetermined size.
[0123]
In the granulation operation of the granular material 30, first, a mixture of a base material and a granulation aid is attached on the outer peripheral surface of the core 36, and then the carbon fiber 24 is attached. Also good.
[0124]
Further, the carbon fiber 24 or a mixture of the base material and the granulation aid is attached so as to be applied twice, or attached so as to be applied a plurality of times, and then the next base material and the granulation aid. Or a mixture of carbon fibers 24 may be attached.
[0125]
Thus, when performing the granulation operation | work of the granular material 30, the operation | work which stirs and mixes the carbon fiber 24, a base material, and the granulation auxiliary material is not performed. Therefore, it is possible to prevent the carbon fibers 24 from being broken or from leaving only a plurality of carbon fibers 24 as a lump.
[0126]
If necessary, the outer shape of the mixture of the electromagnetic wave absorber, the base material, and the granulation aid in a predetermined amount around the core 36 as described above is formed into a spherical shape as shown in FIG. 7 or a cylindrical shape as shown in FIG. 8 (in this case, in order to make the core 36 a little smaller than the outer shape of the granular material 30, a small cylindrical shape is used. And form the granular material 30.) or the like.
[0127]
  Next, the core 36, the carbon fiber 24, the base material, and the granulation aid formed in a predetermined shape such as a spherical shape, a small block shape, or a cylindrical shape are baked and hardened at a predetermined temperature in the firing step. 4 to produce a granular material 30 as shown in FIG. 4, FIG. 6, FIG. 7, FIG.The embodiment of the present invention will be described..
[0128]
In this firing step, the granular material 30 may be solidified as it is, or the granular material 30 is formed into a bubble-like space portion in the mixture of the base material and the granulation aid inside. It may be configured to make.
[0129]
Here, when the granular material 30 is solidified as it is, each carbon fiber 24 is arranged corresponding to the tangential direction with respect to each point on the outer peripheral surface of the core 36, so that it is approximately three-dimensionally on average. The carbon fibers 24 are arranged in all directions, and are distributed at a substantially uniform density around the core 36 by the carbon fibers 24 stacked in a plurality of layers and the layer of the mixture of the base material and the granulation aid. Since 24 has a three-dimensional structure in which it is uniformly dispersed, the orientation of each carbon fiber 24 is not aligned in one direction.
[0130]
Further, when the granular material 30 forms a bubble-like space portion in the layer of the mixture of the base material and the granulation aid inside, the shell-like side wall portion 30A surrounds the bubble-like space portion. It is formed.
[0131]
In this case, a foam material (calcium carbonate, silicon carbide, etc.) is further mixed with the base material and the granulation aid, and the cores 36, carbon fibers 24, base material, and foam formed in the granular form in the firing step. The mixture with the material may be fired at a predetermined temperature, and carbon dioxide may be generated to form a porous structure with innumerable void portions (bubble-shaped space portions) and side wall portions 30 </ b> A by bubbles created inside. .
[0132]
The granular material 30 thus configured to be porous has each of the curved surfaces on the inner side of the side wall portion 30A in which the carbon fibers 24 dispersed in the shell-like side wall portion 30A partition the bubble-like space. It arrange | positions so that it may face in the tangential direction corresponding to.
[0133]
As a result, the carbon fibers 24 are arranged so as to be substantially averaged in all three-dimensional directions inside the shell-shaped side wall portion 30A surrounding each bubble-shaped space portion, and the shell-shaped side wall portions 30A. The carbon fibers 24 are distributed at a substantially uniform density in the inside, and the carbon fibers 24 are uniformly dispersed to form a three-dimensional structure.
[0134]
That is, in the granular material 30, each carbon fiber 24 is arranged in various directions around the core 36 inside the granular material 30, and is dispersed in an average manner, so that the orientation of each carbon fiber 24 is unidirectional. It ’s no longer necessary.
[0135]
Moreover, since the granular material 30 comprised as mentioned above has a bubble-shaped space inside, it can achieve weight reduction of its own weight.
[0136]
The granular material 30 configured as described above causes an electromagnetic wave transmitted from the surface thereof to interfere with the carbon fiber 24 that is a dielectric material or magnetic material inside the granular material 30, thereby promoting an internal loss and an electromagnetic wave absorption effect. obtain.
[0137]
In addition, since a large number of voids in the granular material 30 exist uniformly in all directions, it is difficult for surface reflection to occur even when the incident angle of the electromagnetic wave on the surface of the granular material 30 is shallow. It can be easily absorbed by entering inside.
[0138]
In addition, concrete, asphalt, and resin mixed material incorporating light-weight granular material 30 as a structural material (aggregate) can be used as a lightweight building material for walls, floors, roofs, etc. by molding into a panel shape.
[0139]
Lightweight construction materials constructed as described above are used as construction materials for toll road toll booth facilities, tunnel tunnels, and other general locations that radiate electromagnetic waves, minimizing the impact on living organisms caused by prolonged electromagnetic radiation exposure. It becomes possible to make use as a technique for suppressing the above.
[0140]
2 and 3, the incident wave reflected on the back electromagnetic wave reflecting material (electromagnetic wave reflecting layer 20) is reversed by adjusting the thickness of the layer containing the granular material 30 (surface layer 18). It is possible to obtain an internal loss due to the canceling action by converting into the phase.
[0141]
Further, the electromagnetic characteristics of the granular material 30 can be adjusted by increasing or decreasing the amount of voids provided therein. Normally, the dielectric constant can be reduced by increasing the amount of voids.
[0142]
Next, the case where the surface layer 18 as a structure on the road is configured using the granular material 30 having the electromagnetic wave absorption characteristics configured by mixing the carbon fibers 24 as described above will be described.
[0143]
In this case, a predetermined large number of granular materials 30 having electromagnetic wave absorption characteristics constituted by mixing the carbon fibers 24 are prepared, a predetermined appropriate amount of a binder is added thereto, and these are mixed well by stirring and rolling. A road surface layer 18 as shown in FIG. 5 is formed by construction work such as pressure.
[0144]
By configuring the surface layer 18 in this way, each granular material 30 is stably dispersed within the range in which the surface layer 18 is formed when the granular material 30 and the binder 34 are mixed. Along with this, the carbon fibers 24 mixed in the granular materials 30 are also dispersed on average within the range in which the surface layer 18 is formed, and the surface layer 18 in the state shown in FIG. 5 is formed.
[0145]
Next, a case where the surface layer 18 is configured by integrating three layers having different packing densities of the carbon fibers 24 so that electromagnetic waves can easily enter from the surface side of the surface layer 18 and reduce reflection of the electromagnetic waves as shown in FIG. explain.
[0146]
In this case, the granular material 30 having the highest content of the carbon fibers 24 mixed with the largest amount of carbon fibers 24 in the interior of the granular material 30 and the interior of the granular material 30 as compared with others. The content rate of the carbon fiber 24 mixed with the medium carbon fiber 24 is medium, and the content rate of the carbon fiber 24 mixed with the least amount of carbon fiber 24 in the granular material 30 as compared with the other. The lowest granular material 30 is prepared.
[0147]
And using the granular material 30 with the highest content of the carbon fiber 24, the lowest layer 18A ( The third layer).
[0148]
Next, the intermediate layer 18B (second layer) of the surface layer 18 is configured in a state where the mixing ratio with other aggregates is medium by using the granular material 30 having a medium carbon fiber 24 content.
[0149]
Next, the uppermost layer 18C (first layer) of the surface layer 18 is configured with the lowest mixing ratio with other aggregates using the granular material 30 having the smallest carbon fiber 24 content. A surface layer 18 having a monolithic structure as illustrated in FIG.
[0150]
It should be noted that only the content ratio of the carbon fiber 24 or the mixing ratio with other aggregates is adjusted so that the lowermost layer 18A (third layer), the intermediate layer 18B (second layer), the uppermost layer 18C ( The first layer may be configured.
[0151]
As can be understood from the diagram shown in FIG. 12, in the surface layer 18 having an integral structure as described above, the first layer on the surface side has the smallest content of the carbon fibers 24, so that the first layer on the surface side is incident. Therefore, the electromagnetic wave can be absorbed while reducing reflection of the electromagnetic wave on the surface of the surface layer 18. And in this monolithic surface layer 18, the electromagnetic wave is allowed to pass through the second layer having a medium carbon fiber 24 content while gradually absorbing the electromagnetic wave, and the third layer having the highest carbon fiber 24 content. Can sufficiently absorb electromagnetic waves.
[0152]
Next, when configuring a road part constructed with a pavement material that is an electromagnetic wave absorbing material using the above-described granular material having electromagnetic wave absorption characteristics, at least in the required range of the road in the automatic toll collection shown in FIG. The operation and effect will be described.
[0153]
The pavement material used here is configured to absorb radar millimeter waves (including carbon fiber 24 having a length corresponding to the radar millimeter waves and emitted from the wireless communication device of the automatic toll collection device 12. For example, it is configured to include carbon fiber 24 having a corresponding length so as to absorb electromagnetic waves in a frequency band of 5.80 GHz.)
[0154]
In this automatic toll collection station, a millimeter wave is emitted from a vehicle detection radar of the automatic toll collection device 12 arranged there, and a vehicle 14 traveling on the road toward the automatic toll collection device 12 is detected. .
[0155]
At this time, since the millimeter wave emitted from the radar device is absorbed by the road having the electromagnetic wave absorption function, the radar device does not malfunction due to an electromagnetic wave failure caused by an unnecessary electromagnetic wave reflected on the road, and the vehicle 14 is properly operated. It can be detected.
[0156]
When the radar device of the automatic toll collection device 12 detects the vehicle 14 at a predetermined position in this way, the wireless communication device of the automatic toll collection device 12 uses a communication signal MW that is a radio wave in the frequency band of 5.80 GHz, for example. Then, wireless communication is performed with an automatic fee payment device mounted on the vehicle 14, and a fee collection process is executed.
[0157]
At this time, the radio wave of 5.80 GHz emitted from the wireless communication device of the automatic toll collection device 12 is absorbed when it hits a road having an electromagnetic wave absorbing function.
[0158]
Therefore, the electromagnetic wave disturbance that the radio wave of 5.80 GHz emitted from the wireless communication device is reflected on the road and is received by the following vehicle approaching immediately after the vehicle 14 detected at the predetermined position. Thus, it is possible to effectively prevent a malfunction in which the fee collection processing of the vehicle 14 detected at a predetermined position and the fee collection processing of the following vehicle are performed simultaneously.
[0159]
Although not shown, when the pavement material manufactured using the granular material 30 having the electromagnetic wave absorption characteristics of the present embodiment is used in an automobile driving support system, for example, along the driving path of the automobile on the road A part of the road within a range necessary for removing the electromagnetic interference around the lane marker installed at each predetermined position of the road is made of a pavement material having an electromagnetic wave absorbing function.
[0160]
That is, a road with a pavement material having an electromagnetic wave absorbing function arranged in a circle with a predetermined radius surrounding the lane marker, or a pavement material having an electromagnetic wave absorbing function in an oval shape along the longitudinal direction of the road.
[0161]
By configuring in this way, the detection device such as the radar of the driving support device mounted on the vehicle traveling on the road detects the position of the lane marker properly without detecting electromagnetic interference and detects the appropriate driving route. it can. Furthermore, various communication can be appropriately performed between the communication device of the lane marker arranged on the road and the vehicle without receiving electromagnetic interference.
[0162]
In the above-described embodiment, the configuration in which the pavement material using the granular material 30 having the electromagnetic wave absorption characteristics is used for road pavement has been described. However, the granular material 30 having the electromagnetic wave absorption characteristics may be various structures. Can be used as a material.
[0163]
That is, the granular material 30 having electromagnetic wave absorption characteristics is a material constituting a floor surface of a parking lot, a material constituting a floor surface in a building, a material constituting a runway or a material constituting a floor surface of a hangar, tunnel tunnel In addition, it can be used as a material capable of constructing all structures that receive electromagnetic waves.
[0164]
Also, a mixed material using asphalt, concrete, resin binder, etc., as the particulate material 30 having electromagnetic wave absorption characteristics is manufactured, and the shape and required thickness of the structure at the construction site are manufactured using the mixed material. Since they can be molded together, various buildings can be constructed on site.
[0165]
In this way, in the ITS related technology using electromagnetic wave communication, etc. in facilities around road toll booths, tunnel tunnels, and other places where electromagnetic waves are irradiated, using granular material 30 having electromagnetic wave absorption characteristics, Harmful scattered electromagnetic waves can be efficiently removed.
[0166]
【The invention's effect】
  1stly, the granular material which has the electromagnetic wave absorption characteristic of this invention has the electromagnetic wave absorber which absorbs electromagnetic waves around the lump core.A bubble-like space was formedIt is constituted by adhering and solidifying an evenly dispersed and mixed material in a substrate.
[0167]
Thereby, since the electromagnetic wave absorber is dispersed and arranged on the periphery of the nucleus inside the granular material, it is possible to obtain a granular material having stable electromagnetic wave absorption characteristics with stable electromagnetic wave absorption characteristics. Further, the granular material having the electromagnetic wave absorption characteristics has a function of absorbing electromagnetic waves satisfactorily. Furthermore, if a layer of the base material and the electromagnetic wave absorber mixed with a substantially uniform thickness is formed around the core, the outer shape and size of the granular material can be made uniform.
[0168]
  Second, the method for producing a granular material having electromagnetic wave absorption characteristics according to the present invention is as follows.A bubble-like space was formedAn electromagnetic wave absorber that absorbs electromagnetic waves in a base material is uniformly dispersed and mixed, and is attached to the periphery of a lump of nuclei, and then the base material and the electromagnetic wave absorber are mixed around the core. It is manufactured by solidifying it in a state where it is attached.
[0169]
  As a result, it is solidified integrally around the nucleus.A bubble-like space is formedIn addition, a granular material in which an electromagnetic wave absorber is dispersed in an average in the substrate can be easily produced. Furthermore, the outer shape and size of the granular material can be made uniform. Therefore, there is an effect that a granular material having electromagnetic wave absorption characteristics can be mass-produced with stable quality..
[0170]
Thirdly, the method for producing a granular material having electromagnetic wave absorption characteristics is obtained by adhering an electromagnetic wave absorber that absorbs electromagnetic waves and a foam material uniformly dispersed in a base material around a lump core. Then, the mixture of the base material and the electromagnetic wave absorber adhering to the periphery of the core is baked in a state where it is adhered, so that it is solidified integrally in a state where it is foamed at the portion including the base material. .
[0171]
This makes it possible to easily manufacture a granular material in which an electromagnetic wave absorber is averagely dispersed in a base material integrally solidified in a state of being foamed around the core. Furthermore, the outer shape and size of the granular material can be made uniform. Electromagnetic wave absorbers placed on the side walls between the gaps inside the granular material with electromagnetic wave absorption characteristics are dispersed and arranged on the average corresponding to the surfaces that partition the gaps, thus absorbing electromagnetic waves well. There is an effect that can be done.
[0176]
  First4In addition, in the method for producing a granular material having electromagnetic wave absorption characteristics, an electromagnetic wave absorber that absorbs electromagnetic waves is attached to the outside of a lump nucleus, and a base material and a foam material or a material containing these are attached to the outside of the nucleus. Next, the electromagnetic wave absorber and the base material and the foam material or a material containing these are adhered to the outside of the core and fired in a laminated state, so that the part including the base material is integrally foamed. Solidify to produce a granular material.
[0177]
As a result, the electromagnetic wave absorber is disposed on the side wall portion between the gaps in the base material integrally solidified in a foamed state around the core, and is dispersed on an average corresponding to the surface partitioning the gap portion. Since it is disposed, it can absorb electromagnetic waves well. Therefore, a granular material having electromagnetic wave absorption characteristics can be mass-produced with stable quality, and an inexpensive product can be provided.
[0178]
  First5In addition, the granular material having electromagnetic wave absorption characteristics of the present invention is constituted by using carbon fibers as the granular material having the electromagnetic wave absorption characteristics.
[0179]
As a result, the design can be changed so that the required electromagnetic wave absorption characteristics can be obtained simply by changing and adjusting the length of the carbon fiber corresponding to the wavelength of the electromagnetic wave to be absorbed, so the wavelength of the electromagnetic wave to be absorbed is different. Even in this case, there is an effect that it is possible to cope without changing the weight of the granular material using the carbon fiber.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a particulate material having electromagnetic wave absorption characteristics of the present invention and an automatic toll collection station according to an embodiment of a manufacturing method thereof.
FIG. 2 is a cross-sectional view showing a cross-sectional structure of a road having an electromagnetic wave absorption function according to an embodiment of a granular material having electromagnetic wave absorption characteristics of the present invention and a method for producing the same.
FIG. 3 is a cross-sectional view showing another cross-sectional structure of a road having an electromagnetic wave absorption function according to an embodiment of a granular material having electromagnetic wave absorption characteristics of the present invention and a manufacturing method thereof.
FIG. 4 is a front view showing a granular material according to an embodiment of the granular material having electromagnetic wave absorption characteristics of the present invention.
FIG. 5 is a longitudinal sectional view showing a state when the granular material having electromagnetic wave absorption characteristics of the present invention is integrated with a binder.
FIG. 6 is a perspective view showing a state when the granular material having electromagnetic wave absorption characteristics of the present invention is formed into a spherical shape.
FIG. 7 is a perspective view showing a state when the granular material having electromagnetic wave absorption characteristics of the present invention is formed into a random lump shape.
FIG. 8 is a perspective view showing a state when the granular material having electromagnetic wave absorption characteristics of the present invention is formed into a cylindrical shape.
FIG. 9 is a longitudinal sectional view showing a granular material having electromagnetic wave absorption characteristics of the present invention.
FIG. 10Reference exampleIt is an expanded longitudinal cross-sectional view which shows a part of porous electromagnetic wave absorption material which has a magnetic wave absorption characteristic.
FIG. 11 is a cross-sectional view showing a part of a structure configured in a three-layer structure using the granular material having electromagnetic wave absorption characteristics of the present invention.
FIG. 12 is an explanatory diagram illustrating an electromagnetic wave absorption state in a structure having a three-layer structure using a granular material having electromagnetic wave absorption characteristics of the present invention.
FIG. 13Reference exampleIt is a schematic sectional drawing which shows the state which made carbon fiber adhere to the whole outer peripheral surface of the nucleus which concerns on embodiment in the manufacturing method of the granular material which has the electromagnetic wave absorption characteristic of this.
FIG. 14Reference exampleIn the method for producing a granular material having electromagnetic wave absorption characteristics, a mixture of a base material and a granulating aid is layered on the entire outer peripheral surface of a state in which carbon fibers are attached to the entire outer peripheral surface of the nucleus according to the embodiment. It is a schematic sectional drawing which shows the state made to adhere to.
FIG. 15Reference exampleAs an electromagnetic wave absorber on the entire outer peripheral surface of carbon fiber attached to the outside of the core according to the embodiment in the method for producing a granular material having electromagnetic wave absorption characteristics and further coated with a mixture of a base material and a granulation aid It is a schematic sectional drawing which shows the state which made carbon fiber adhere.
FIG. 16Reference exampleThe outer peripheral surface of carbon fiber, a mixture of a base material and a granulation aid, and three layers of carbon fibers adhered to each other outside the core according to the embodiment of the method for producing a granular material having electromagnetic wave absorption characteristics It is a schematic sectional drawing which shows the state which adhered what was mixed with the base material and the granulation auxiliary material to the whole, and comprised the granular material.
[Explanation of symbols]
12 Automatic fee collection device
18 Surface
18A Bottom layer
18B Intermediate layer
18C top layer
20 Electromagnetic wave reflection layer
24 carbon fiber
26 carbon grains
30 granular material
30A side wall
34 Binder
36 nuclei

Claims (5)

A mass of nuclei,
A base material that is adhered and solidified around the core to form a bubble-like space ;
An electromagnetic wave absorber that absorbs electromagnetic waves uniformly dispersed and mixed in the base material;
The granular material which has the electromagnetic wave absorption characteristic characterized by having. A mass of nuclei,
An electromagnetic wave absorber disposed outside the core and arranged in a layer containing the core;
A substrate on the outside of the nucleus, arranged in a layer containing the nucleus, and having a bubble-like space formed thereon ,
A granular material having electromagnetic wave absorption characteristics, wherein the electromagnetic wave absorber layer and the base material layer form a laminated structure. In the base material, an electromagnetic wave absorber that absorbs electromagnetic waves and a foam material that is uniformly dispersed and mixed together is attached to the periphery of a lump core,
The step of solidifying in an integrated state in a state of foaming in a portion including the base material, by baking in a state where the base material and the electromagnetic wave absorber are mixed around the core, and
A method for producing a granular material having electromagnetic wave absorption characteristics, characterized by comprising: Attaching an electromagnetic wave absorber that absorbs electromagnetic waves to the outside of a lump of nuclei;
Attaching a base material and a foam material or a material containing them to the outside of the core;
On the outside of the core, the electromagnetic wave absorber and the base material and the foam material or a material containing these are adhered and laminated, and then fired in a state of being integrally foamed in the part including the base material. Solidifying process;
A method for producing a granular material having electromagnetic wave absorption characteristics, characterized by comprising: The granular material having electromagnetic wave absorption characteristics according to claim 1 or 2, wherein the electromagnetic wave absorber is carbon fiber.

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