JP2021093864A - Leakage coaxial cable laying structure, leakage coaxial cable laying method, trough body for storing leakage coaxial cable, polyolefin resin material with excellent flame retardancy and telecommunications characteristics and usage method of polyolefin resin material, and communication method and communication system using leakage coaxial cable laying structure - Google Patents

Abstract

To provide a leakage coaxial cable laying structure that can keep the orientation of a slot constant and suppress the influence of wind from trains, pollution, etc., a polyolefin resin material with excellent flame retardancy and telecommunications characteristics, a usage method of the trough structure, and a communication method, a communication system, and the like using the leakage coaxial cable laying structure.SOLUTION: A trough 3 is made of resin. Inside a closed space formed by the trough 3, a cable support member 11 is arranged, and a leakage coaxial cable 5 is placed on a support portion 33 with a support wire 29 facing downward. In the present invention, it is possible to realize a laying structure of the leakage coaxial cable having high rigidity and excellent linear workability. The present invention also provides a polyolefin resin material having excellent flame retardancy and telecommunications characteristics, a usage method of a trough structure material, a communication method, and a communication system using a laying structure of the leakage coaxial cable. By using the communication method and the communication system according to the present invention, a good communication state with a vehicle antenna can be realized.SELECTED DRAWING: Figure 11

Description

The present invention relates to a leaky coaxial cable laying structure in which a leaky coaxial cable is laid inside a trough, a method of laying a leaky coaxial cable, a trough body for accommodating the leaky coaxial cable, and a polyolefin resin material having excellent flame retardancy and telecommunications characteristics. And the method of using the material, the communication method using the leakage coaxial cable laying structure, and the communication system.

Conventionally, a leaky coaxial cable may be installed along the track, for example, on the side of a track of a railway or the like. Such a leaky coaxial cable includes an inner conductor, an insulator arranged on the outer periphery of the inner conductor, an outer conductor arranged on the outer periphery of the insulator and having a slot (opening) at a predetermined position, and an outer conductor. It is composed of an outer cover that covers the above and a support wire that supports the main body of the leaky coaxial cable composed of these.

A leaky coaxial cable is a conductor that has an antenna function and is provided with a large number of slots according to the frequency used in the outer conductor in order to transmit a signal and at the same time emit a part of the signal energy as radio waves in the space along the cable. is there. Such leaky coaxial cables are laid especially along railroad tracks, tunnels, underground streets, etc. where radio waves are difficult to transmit, and are used for business radio such as train radio, FM broadcasting, mobile phones, wireless LAN, etc. Will be done.

Here, if the leaky coaxial cable is laid directly on the ground, there is a possibility that the leaky coaxial cable is stolen, the surface of the leaky coaxial cable gets wet, is contaminated, and the performance is deteriorated due to vibration due to wind. Therefore, a general leaky coaxial cable has a support wire on the outer circumference of the coaxial cable, and the support wire is supported by a support member on a fence, a support, or the like, and the leaky coaxial cable is laid.

As a support member for such a leaky coaxial cable, for example, a leaky coaxial cable including a cable holder for gripping the leaky coaxial cable laid along the track for vehicle wireless communication and a fixing bracket for attaching the cable holder. Supports for use have been proposed (Patent Document 1).

The cable holder of the support for the leaky coaxial cable of Patent Document 1 is formed of a flexible elastic material. A flexible elastic plate portion is provided at the attachment portion to the fixing bracket. The cylindrical portion that holds the leaky coaxial cable is integrally molded with the elastic plate portion, and the elastic plate portion can swingably support the leaky coaxial cable when the fixing bracket receives wind pressure from the track side. ..

Further, in the method of fixing the leaky coaxial cable in Patent Document 1, even if the leaky coaxial cable sways, the stress concentration can be dispersed by the bending deformation of the cable holder. Therefore, the leaky coaxial cable is prevented from being damaged by local refraction fatigue, the durability is improved, and the life of the leaky coaxial cable can be dramatically extended.

In addition, a self-supporting leaky coaxial cable equipped with a support wire is hung and laid in a signal leakage space set deep in a closed space such as a tunnel or indoors, and a closed space is provided for this leaky coaxial cable. A method of laying a cable for a signal leakage system in a closed space by suspending and laying a power supply cable for supplying a signal from the outside has been proposed (Patent Document 2).

Patent Document 2 relates to a cable laying method in a signal leakage system used for wireless transmission in a closed space such as a tunnel or indoors, and a power supply cable used for this method. The power supply cable of Patent Document 2 is provided with an insulator made of foamed resin interposed between an outer conductor made of a ring corrugated tube and an inner conductor arranged at the center thereof, and a support wire is provided along the coaxial cable body. It is a self-supporting cable. In Patent Document 2, the leaky coaxial cable and the power feeding cable are supported by fixing metal fittings arranged at appropriate positions in a closed space via their respective support wires. The leaky coaxial cable is fixed in a closed space by tightening a pair of clamp metal fittings with bolts and nuts to an inverted L-shaped base metal fitting.

Further, when pulling out a communication cable from a drum, a method of laying a cable that can be laid linearly without applying high tension and does not leave a curl or the like has been proposed (Patent Document 3).

In Patent Document 3, the high-rigidity support and the leaky coaxial cable are integrally covered with a sheath. Further, the material or cross-sectional shape of the high-rigidity support is selected so that the rigidity of the high-rigidity support is greater than the rigidity of the composite of the leaky coaxial cable and the sheath excluding the high-rigidity support. As a result, the linearity of the entire communication cable can be ensured.

More specifically, in the invention of Patent Document 3, the high-rigidity support is gripped by the support metal fittings via the sheath. Then, the high-rigidity support is fastened and fixed to the support metal fittings using bolts, and this is fixed to the wall surface or the utility pole. In this way, the communication cable is supported and fixed. At this time, since the entire communication cable maintains uniform linearity, the slots provided in the outer conductors of the leaky coaxial cable are always arranged so as to be accurately oriented in one direction. Therefore, good communication is possible.

Further, there has been proposed a connector for a leaky coaxial cable of a communication device in which a bundled leaky transmission line in which a plurality of leaky coaxial cables are arranged side by side at regular intervals and arranged in parallel is used as an array antenna (patented). Document 4).

The plurality of leaky coaxial cables of Patent Document 4 are used in a MIMO (Multiple-Input and Multiple-Output) communication system in which a plurality of antennas are used on the transmitting side and the receiving side, respectively. The leaky coaxial cable is provided with a linear central conductor, an insulator that covers the central conductor concentrically, and a plurality of slots that periodically line up in the extension direction while covering the insulator concentrically. It has an outer conductor and a sheath that covers the outer conductor concentrically. The plurality of leaky coaxial cables are arranged in parallel at regular intervals and connected by a leaky coaxial cable connector. The leaky coaxial cable connector includes a plurality of grips for gripping the leaky coaxial cable, a connecting portion for connecting each of the plurality of grips, and an opening portion for opening a part of the grip.

Further, a method of laying a leaky coaxial cable capable of laying a leaky coaxial cable at low cost and a cable erection structure capable of laying the leaky coaxial cable at low cost have been proposed (Patent Document 5).

In the method of laying the leaky coaxial cable of Patent Document 5, first, a metal overhead wire is hung between the columns (hanging step), and the leaky coaxial cable is temporarily fixed along the overhead wire (temporary fixing step). Next, a hanging tool made of a spiral non-metal wire is wound around the axis of the overhead wire and the leaky coaxial cable. The hanging tool is arranged between the columns while the overhead wire and the leaky coaxial cable are inserted into the cavity formed by the hanging tool (extension step). Finally, the temporary fixing of the leaky coaxial cable is released (temporary fixing release process). From the above, the leaky coaxial cable can be laid. In the method of laying the leaky coaxial cable of Patent Document 5, a hanging tool made of a spiral non-metal wire is wound around the axis of the overhead wire and the leaking coaxial cable, and the overhead wire and the leaking coaxial cable are formed in the cavity formed by the hanging tool. It is characterized by the stretching process in which the hanging tool is stretched between the columns while the cable is inserted.

Further, the optical unit transmission has a structure in which the support line, the leaky coaxial cable, and the pipe for transmitting the optical unit are commonly covered, and the leaky coaxial cable, the support line, and the pipe for transmitting the optical unit are sequentially arranged from the bottom to the top. A leaky coaxial cable with a universal pipe has been proposed (Patent Document 6).

Normally, when a leaky coaxial cable is laid near a railroad track, the leaky coaxial cable receives the wind pressure of the train and causes large vibration every time the train passes, and the metal material may cause fatigue failure. For this reason, it is necessary to firmly fix the leaky coaxial cable, but if it is firmly fixed in this way, the workability of the disconnection work will be poor, and after the disconnection work, the support wire will be leaked by some means. Need to be tied to.

On the other hand, in the leaky coaxial cable with the optical unit transmission pipe of Patent Document 6, since the pipe is arranged above the support line and the leaky coaxial cable is arranged below the support line, the support line and the pipe are stopped. Only leaky coaxial cables can be fixed with metal fittings and are not supported. Therefore, even if the leaky coaxial cable is laid near the train track that receives strong wind pressure, it is less likely to shake and fatigue fracture due to vibration is less likely to occur as compared with the conventional leaky coaxial cable. Further, the leaky coaxial cable can be easily separated by simply disconnecting the joint portion between the leaky coaxial cable and the support wire, and the pipe can be easily separated by simply disconnecting the joint portion between the pipe and the support wire.

Japanese Unexamined Patent Publication No. 2005-130543 Japanese Unexamined Patent Publication No. 2002-135931 Japanese Unexamined Patent Publication No. 2007-273247 Japanese Unexamined Patent Publication No. 2016-019047 Japanese Unexamined Patent Publication No. 2008-220161 Japanese Unexamined Patent Publication No. 09-265333

Here, when transmitting and receiving radio waves via the slot of the leaky coaxial cable, the direction of forming the slot with respect to the transmission / reception target is important. The orientation of this slot is determined by the relative relationship between the slot spacing and the wavelength. Therefore, when such a leaky coaxial cable is used for transmission / reception to / from a train, the leaky coaxial cable is provided so that the slots of the leaky coaxial cable are appropriately arranged at a predetermined angle and at a predetermined interval with respect to the antenna on the receiving side. Need to lay.

However, if the leaky coaxial cable is made swingable as in Patent Document 1, it is difficult to keep the slot direction constant in a predetermined direction. In addition, there is a possibility that the performance of the leaky coaxial cable may be deteriorated due to water wetting or contamination, or due to vibration due to wind.

Similarly, the laying method of Patent Document 2 does not consider laying in a place where the air pressure fluctuation is large, such as the side of a Shinkansen track, and is not a fixing method when it is affected by the air pressure fluctuation. Further, as in Patent Document 1, there is a possibility that the surface of the leaky coaxial cable may be wet or contaminated, or the performance may be deteriorated due to vibration due to wind.

Further, Patent Document 3 also has the same problems as Patent Documents 1 and 2, and is also applicable because it is necessary to adjust the rigidity and cross-sectional shape of the high-rigidity support and the composite of the coaxial cable and the sheath. There are limits to possible leaky coaxial cables.

Similarly, in Patent Documents 4 to 6, it is difficult to suppress the influence of wind, dirt, etc., and to keep the slot direction constant.

The present invention has been made in view of such a problem, and it is possible to keep the orientation of the slot constant, and to suppress the influence of wind from a train or the like and the influence of water wetting or contamination. The leaky coaxial cable laying structure that can mitigate the deterioration of the cable due to environmental temperature changes and ultraviolet irradiation, the leaky coaxial cable laying method, the trough body for the leaky coaxial cable, and the polyolefin with excellent flame retardancy and telecommunications characteristics. Provided are a resin material and a method of using the material for a trough structure, a communication method using a leaky coaxial cable laying structure, and a communication system, and the above communication method and the above communication system are used to be good with an on-vehicle antenna. The purpose is to perform various wireless communications. In particular, for this reason, in the trough laying structure for leaky coaxial cables, in addition to weather resistance and impact characteristics, communication is performed between the cable in the trough and the train, so that the trough absorbs radio waves or the trough causes it. Since deterioration of transmission characteristics becomes a problem, the invention was made in consideration of the dielectric constant and communication characteristics of the trough structure used for the laying structure of the leaky coaxial cable. Furthermore, he has invented a communication method and a communication system using this.

In order to achieve the above-mentioned object, the first invention includes a trough body and a trough lid made of resin, and a leaky coaxial cable housed in the trough body. In a closed space formed by a trough having side walls standing on both sides and having the trough lid covered on the trough body, a resin or rubber cable support member is provided at a predetermined position in the longitudinal direction of the trough. The leaky coaxial cable laying structure is arranged so that the leaky coaxial cable is placed on a support portion of the cable support member with the support wire facing downward.
In the laying structure of the leaky coaxial cable using this trough, the trough has a high rigidity and a linear shape, and a material having a higher flexural modulus than the protective member of the corrugated structure is used. An excellent laying structure can be obtained, and as a result, an excellent aesthetic appearance can be obtained.
Further, if a material having a dielectric constant of 3.15 or less is used for the resin forming the trough structure, it is possible to obtain a laying structure of a leaky coaxial cable having excellent communication characteristics with little transmission loss and coupling loss as described later. ..
Therefore, by using a resin containing an inorganic substance as the resin used for the trough structure, in addition to communication properties, mechanical properties such as tensile strength, flexural modulus, and impact strength, as well as corrosion resistance and weather resistance can be obtained. A leaky coaxial cable laying structure using a trough structure with excellent flame retardancy can be used.
The feature of the laying structure of the leaky coaxial cable of the present invention is that the dielectric constant can be suppressed to a predetermined value of 3.15 or less even if the resin material contains an inorganic substance in order to improve the above-mentioned characteristics. Even if the cable is stored in the trough, it has succeeded in obtaining the same communication characteristics as when it is exposed on the concrete ground.

The trough body has a substantially U-shaped cross section, and connecting portions are formed at one end and the other end of the trough body and the trough lid, and by connecting the connecting portions, respectively. It is desirable that a plurality of the troughs can be connected. At this time, the trough can be connected at a bending angle within a range of 4 ° or less that does not exceed the maximum bending angle of the leaky coaxial cable. When the leaky coaxial cable is laid in a bent portion, the bent portion can be bent not only in the horizontal direction but also in the vertical direction, but the bending angle of the trough connection portion must be 4 ° or less. desirable. Incidentally, the maximum bending angle of the leaky coaxial cable is said to be 5 ° or less, but when the outer conductor is made of copper, it is desirable that the maximum bending angle is 4 ° or less with a margin. At this time, the maximum bending angle refers to the maximum allowable bending angle when the leaky coaxial cable is restrained by a predetermined distance and the cable is bent to one side. Here, when the outer conductor of the leaky coaxial cable is aluminum, the bending angle of the bent portion of the leaking coaxial cable may be formed to be 2 ° or less, which does not exceed 2 ° of the maximum bending angle in the case of the aluminum conductor. desirable.

In a trough structure formed by connecting a predetermined number of the trough main body and the trough covered with the trough lid, which are adjacent to each other, at a predetermined position in the longitudinal direction inside a closed space formed by the trough structure. A plurality of the cable support members are arranged at predetermined intervals, and the cable support members are arranged at any position on the support portion formed at a predetermined height of the cable support members. It is desirable that a leaky coaxial cable be placed.

The support portion of the cable support member is formed in a substantially semicircular shape so that the leaky coaxial cable can be accommodated, and the leaky coaxial cable is the cable support member and has a predetermined height from the bottom portion of the trough. Therefore, it is desirable that the cable is supported at a predetermined angle. By accommodating the support wire covered with the outer sheath in the groove formed at a predetermined angle in the cable support member in this way, if the leaky coaxial cable is supported at a predetermined height and a predetermined angle, the leaky coaxial cable Slots can be arranged at a predetermined angle.

At least a part of the support portion of the plurality of cable support members is formed at a position offset by a predetermined distance from the center in the width direction of the cable support member, and the leaky coaxial cable is formed in the width direction of the cable support member. On the support portion arranged at a position alternately offset to the left and right by a predetermined distance from the center of the cable, the support portion is curved and loosely arranged in a substantially S shape so that continuous bent portions are alternately formed in the longitudinal direction. You may. By slackening in a substantially S shape in the horizontal direction in this way, it is possible to respond not only to temperature expansion and contraction but also to changes in tension due to an earthquake, and it is possible to prevent deformation of the leaky coaxial cable. ..

Here, it is desirable that the bending angle of the bent portion of the leaky coaxial cable loosely arranged in a substantially S shape is formed to be 0.5 ° or more and 2 ° or less. In particular, when the outer conductor of the leaky coaxial cable is aluminum, it is desirable that the bending angle of the bent portion of the leaking coaxial cable is formed to be 2 ° or less, which does not exceed the maximum bending angle of 2 ° in the case of the aluminum conductor. .. The bending angle of the leaky coaxial cable referred to in the present invention is the angle formed by the straight line connecting the cross-sectional centers of the leaky coaxial cables between the support portions supported by the adjacent support members with the center line in the longitudinal direction of the trough body. .. This is an apparent bending angle because the straight line connecting the centers of the support portions of the adjacent support members coincides with the angle formed by the center line in the longitudinal direction of the trough body. The actual leaky coaxial cable is arranged with an S-shaped slack with respect to this apparent bending angle. Therefore, when the apparent bending angle is 4 °, the leaky coaxial cable is loosely arranged in an S shape, so that the bending angle of the maximum bending portion corresponding to both sides of the support member is smaller than 4 °. Become. It is desirable that the bending angle of the leaky coaxial cable loosely arranged in a substantially S shape is 2 ° or less and 0.5 ° or more, which is the allowable bending angle of the outer conductor of the cable.

The cable support members can be arranged at intervals of 1 m or more (unit length or more of the trough) of 6 m or less of the trough structure, but the cable support members may be provided at intervals of 2 m or more and 6 m or less. desirable. In particular, the distance between the support members of the leaky coaxial cable needs to be 6 m or less in order to suppress bending due to the weight of the cable itself.

The cable support member may be formed integrally with the trough body made of resin. Here, the trough body may be made of a resin, but it is desirable that the trough body is made of a polyolefin resin having excellent dielectric properties and water absorption resistance. As the polyolefin resin, polyethylene, polypropylene or a mixed resin thereof can be used. As the polyolefin resin, a polyolefin-based recycled resin can be used. It is desirable that the mass ratio of polyethylene and polypropylene of the polyolefin-based recycled resin is about 9: 1. This polyolefin-based recycled resin may contain a predetermined amount of inorganic substances in order to improve strength, flame retardancy, weather resistance, and the like. For example, the inorganic substance can be contained in a maximum of 40% by mass, but preferably 36% by mass or less, based on the total mass of the recycled resin containing the inorganic substance. Here, the term "containing up to 36% by mass" with respect to the total mass of the recycled resin is the content ratio of the inorganic substance when the total mass of the resin after containing the inorganic substance is 100% by mass.

As described above, a predetermined amount of inorganic substances such as magnesium hydroxide, calcium carbonate, and titanium oxide is added to the polyolefin-based recycled resin in consideration of strength, flame retardancy, weather resistance, and the like. Here, for example, the mass ratio of each inorganic substance is 19% by mass of magnesium hydroxide, 15% by mass of calcium carbonate, and 2% by mass of titanium oxide in terms of the mass ratio of each inorganic substance to the total mass of the polyolefin-based recycled resin material containing the inorganic substance. It is blended with the target ratio. In mass-produced products, the contents of magnesium hydroxide and calcium carbonate are allowed up to about ± 2% by mass and titanium oxide is allowed up to ± 0.5% by mass. Of course, even if a large amount is blended due to variation, it is necessary not to exceed 40% by mass of the total mass of the polyolefin-based recycled resin at the maximum due to the impact value and cost.

The cable support member is formed separately from the trough body, a fixing portion is formed inside the cross section of the trough, the cable support member is fixed to the fixing portion, and the fixing portion is an inner surface surface of the trough body. And / or the inner ribs facing each other formed so that the cable support member can be inserted and fixed to the inner bottom surface, and the cable support member may be inserted and fixed between the inner ribs.

At this time, it is desirable that the inner rib is not formed on the inner bottom surface of the trough, the inner rib is formed only on the inner side surface of the trough, and the groove for draining water is further formed on the bottom of the cable support member. With such a structure, rainwater does not collect on the bottom of the trough.

Here, the cable support member may be made of either resin or rubber, and a rubber sheet may be attached to at least a support portion of the resin cable support member. By doing so, when tension is applied to the leaky coaxial cable, the frictional force becomes large, and the leaky coaxial cable is less likely to shift in the event of an earthquake or the like.

The leaky coaxial cable mounted on the cable support member is bound to the cable support member by a string-shaped fixing member so that the leaky coaxial cable does not deform in cross section. It may be fixed to the cable support member.

When the trough lid is fixed to the trough body with a fixing bolt, a pressing body made of a polyethylene foam sheet is used in at least a part of the arrangement portion of the cable support member on which the leaky coaxial cable is placed. The leaky coaxial cable placed on the cable support member is placed on the leaky coaxial cable by pressing the pressing body within the range of 0.2% of the cross-sectional deformation distortion rate of the leaky coaxial cable. It may be a fixed structure of a leaky coaxial cable to be fixed.
Further, when the trough lid is fixed to the trough main body with a fixing bolt, a pressing body made of a polyethylene foam sheet is formed in at least a part of the arrangement portion of the cable support member on which the leaky coaxial cable is placed. , The leaky coaxial cable placed on the cable support member by pressing the pressing body within the range of 0.2% of the cross-sectional deformation distortion rate of the leaky coaxial cable. A leaky coaxial cable laying structure may be used, which is characterized in that the pull-out force per 100 m of the cable can be fixed so as to be 300 kg or more.

The bottom of the trough body may be provided with a trough fixing bolt insertion hole, and the trough body may be fixed to the concrete ground by an anchor bolt inserted into the trough fixing bolt insertion hole.

An existing long hole-shaped bolt insertion hole for fixing the trough formed in the longitudinal direction and the width direction of the trough body, or the center of the back surface of the bottom surface in the width direction. Anchor inserted into any of the trough fixing bolt insertion holes formed at any position of a groove between the ribs formed on the trough with predetermined lengths facing each other along the longitudinal direction of the trough. When the trough body is fixed to the concrete ground by the bolt, it may be possible to adjust the formation position of the trough fixing bolt insertion hole so as to correspond to the fixing position of the anchor bolt. In addition, since the connection part of the trough body can be bent by 4 ° or less in the left-right direction and the up-down direction, in addition to the formation position of the trough fixing bolt insertion hole, the fixing position in the width direction of the trough body It is possible to adjust both the positional deviation (angle deviation).

The farther the distance from the feeding point is between the connection portions that connect the leaky coaxial cables to each other, the more the slot arrangement angle of the leaky coaxial cable is set with respect to the cable axis direction at predetermined intervals of the leaky coaxial cable. The slots may be arranged at small intervals so that the slots become larger or have a higher density.

It is desirable that the connection portion for connecting the leaky coaxial cables to each other is arranged at a position other than the arrangement portion of the cable support member of the trough structure.

The leaky coaxial cable is placed at a predetermined height on the resin cable support member inside the closed space formed by the trough structure formed by connecting the trough with the trough lid covered to the trough body. The communication characteristics under predetermined conditions in the 400 to 440 MHz band when placed at a predetermined angle are such that the leaky coaxial cable is placed at a predetermined height on the cable support member arranged on the concrete ground in the absence of the trough structure. It is possible to have communication characteristics in the range of ± 2 dB / km for transmission loss and ± 2 dB or less for coupling loss when compared with the case where the cable is placed at a predetermined angle, but the transmission loss is ± 1 dB /. It is desirable to have communication characteristics within km and within ± 1 dB of coupling loss.

Further, as a test result in the communication characteristic confirmation test in the 400 to 440 MHz band of the trough structure, even when the trough structure in which the outer surface and the inner surface of the trough structure are wetted with water to absorb water is used. Communication characteristics equivalent to those when the outer and inner surfaces of the trough structure are in a dry state can be obtained, and the leakage occurs on the cable support member whose height is adjusted on the concrete ground in the absence of the trough structure. It is desirable that the coaxial cable has communication characteristics in the range of ± 2 dB / km or less and the coupling loss within ± 2 dB when compared with the coaxial cable placed at a predetermined height and a predetermined angle. More preferably, the communication characteristics should be such that the transmission loss is within ± 1 dB / km and the transmission loss is within ± 1 dB.

It is desirable that the resin material forming the trough structure is a polyolefin-based recycled resin containing an inorganic substance or a polyolefin resin containing an inorganic substance.

The dielectric constant of the polyolefin-based recycled resin forming the trough structure at a frequency of 400 to 440 MHz measured by the capacitance method is 3.15 or less, and the trough lid and the trough body constituting the trough structure are formed. It is desirable that the maximum wall thickness of the is formed to be 10 mm or less. As described above, when the dielectric constant and the maximum trough wall thickness are equal to or less than the predetermined values, good communication characteristics can be obtained.

According to the first invention, since the leaky coaxial cable can be laid only by arranging the leaky coaxial cable on the cable support member arranged inside the trough, no other fixing member or gripping member is required. is there. In particular, since a resin trough is used, it is possible to prevent the radio waves of the leakage coaxial cable arranged inside from being blocked. For example, by using a trough made of recycled resin, which has excellent flame resistance in addition to high strength, high corrosion resistance, and high weather resistance, it is possible to obtain a leaky coaxial cable laying structure that absorbs less radio waves and enables stable transmission and reception. Can be done. Further, in the laying structure of the leaky coaxial cable of the present invention, a trough having excellent linearity made of a material having excellent bending rigidity is used as compared with the protective member of the corrugated structure, so that the leaky coaxial cable has high rigidity and excellent linear workability. Can realize the laying structure of.

Further, since the trough structure has high rigidity and does not bend while maintaining the laid state even when the environmental temperature changes, it is possible to maintain the laid state substantially parallel to the track, for example. Furthermore, since iron angles and trough bridges are not used, radio waves are not absorbed by the support members of these trough structures. Therefore, the leaky coaxial cable laying structure of the first invention is particularly suitable for communication with a high-speed railway or the like when it is laid on the side of a high-speed railway track.

Further, since the leaky coaxial cable is supported by the cable support member inside the trough, the slots are always at a predetermined height and in a predetermined direction (including the case where they are alternately arranged to face each other) at a predetermined position. It is possible to place it accurately. Therefore, the direction of the electromagnetic wave transmitted from the slot of the leaky coaxial cable can be stabilized. For example, good signals can be transmitted and received between the antenna embedded in the space between the outer frame of the train body and the interior of the train and the leaky coaxial cable. For example, it is possible to prevent meandering and twisting of the leaky coaxial cable due to the influence of reflection from the trough bottom and the winding habit of the leaky coaxial cable that occur when the leaky coaxial cable is placed directly on the trough bottom.

In addition, since the trough is sealed, it is possible to protect the leaky coaxial cable from trauma, animal feeding damage, damage due to contamination, and performance deterioration. Further, since the trough lid is arranged, it is possible to prevent rainwater from entering the trough.

Further, since the leaky coaxial cable is laid in a closed space in the trough where the air pressure fluctuation is small, it is possible to significantly reduce the vibration fatigue of the cable due to the repeated air pressure fluctuation when the train passes. Therefore, by preventing the cable surface from getting wet and deteriorating due to ultraviolet irradiation, it is possible to stabilize the communication characteristics and extend the life of the leaky coaxial cable.

Further, by forming connecting portions at both ends of the trough body and the trough lid, a plurality of troughs can be easily connected to form a trough structure. Even if the connection portions are not formed at both ends of the trough body and the trough lid, as long as the cross-sectional shapes of at least the both ends of the trough body are the same, the longitudinal direction of the trough body is such. It is also possible to form a trough structure by connecting both ends to each other. In any case, it is possible to form a trough structure having a continuous closed space of a predetermined length.

Further, since the leaky coaxial cable is supported at a predetermined distance from the bottom surface of the trough, it is possible to prevent the cable from getting wet even if water enters the trough. Therefore, it is possible to suppress the adhesion of water to the leaky coaxial cable and the shielding of radio waves due to this. Further, since the leaky coaxial cable is arranged at a predetermined height inside the trough by the cable support member, the influence of the reflected wave from the inside of the trough or the concrete ground can be weakened and at the same time, meandering can be prevented.

Further, if the support portion of the cable support member is formed in a shape capable of accommodating the leaky coaxial cable, the leaky coaxial cable can be supported more stably. Therefore, the leaky coaxial cable can be arranged so that the electromagnetic wave transmitted from the slot of the leaky coaxial cable has an appropriate angle with respect to the antenna on the receiving side.

In addition, in order to remove the curl and twist of the leaky coaxial cable, when laying the leaky coaxial cable, apply tension to the leaky coaxial cable to remove the above-mentioned curl and twist to some extent before laying the leaky coaxial cable. To do. Here, by setting the installation interval of the cable support members to 6 m or less, it is possible to suppress the looseness of the leaky coaxial cable. For example, it is possible to suppress the change in the radiation direction of the electromagnetic wave emitted from the slot due to the looseness of the leaky coaxial cable due to its own weight, and to enable stable transmission and reception. In addition, due to the looseness of the leaky coaxial cable, the leaky coaxial cable does not come into contact with the bottom of the trough, and it is possible to prevent the leaky coaxial cable from getting wet when rainwater enters the trough. Damage can be protected.

Further, the installation interval of the cable support members may be 1 m or more in accordance with the length of the trough, but it is preferably 2 m or more. If the installation interval is shorter than this, the cable can be stably supported, but the number of cable support members to be installed increases and the cost increases. Therefore, in order to prevent slack due to the weight of the cable, to support the cable stably, and not to increase the cost, it is necessary to set the installation interval of the cable support members to 2 m or more and 6 m or less. By arranging the cable support members at intervals of 2 m or more and 6 m or less in this way, it is possible to absorb the temperature expansion and contraction of the leaky coaxial cable due to the change in the environmental temperature.

Further, the support portions at positions facing the trough longitudinal direction at positions offset from the center in the width direction of the cable support member alternately to the left and right by a predetermined distance are arranged in a staggered pattern with respect to the longitudinal direction of the trough structure to leak coaxially. By arranging the cables loosely so as to form a continuous bent portion in an S shape, it is possible to arrange the leaky coaxial cable in a loosened state. For this reason, by arranging the cable support members at predetermined intervals, not only is there slack in the vertical direction, but also by arranging them in an S-shape in the horizontal direction, it is not only possible to respond to changes in the environmental temperature, but also due to an earthquake or the like. The stress can be relieved even when the leaky coaxial cable receives tension from the outside, and the leakage coaxial cable can be prevented from being deformed or broken.

The bending angle of the leaky coaxial cable in the S-shaped arrangement is preferably 0.5 ° or more and 2 ° or less. By slackening the cable in an S shape in this way, it is possible to absorb the expansion and contraction of the leaky coaxial cable due to an earthquake or a change in environmental temperature. At this time, since the vicinity of the peak valley portion of the leaky coaxial cable is supported in parallel with the pipe axis direction by the cable support member, it is possible to avoid concentration of bending stress on the top portion of the peak valley portion. In the case of the S-shaped arrangement, the cable support member is installed at a small bending angle such as 0.5 ° to stably bend the leaky coaxial cable, and the peaks and valleys of the S-shaped bending of the cable. In order to avoid local stress concentration on the center, it is necessary to be 2 m or more, but by setting it to 6 m or less, the influence of slack due to its own weight can be eliminated. Therefore, in order to perform stable bending for the S-shaped arrangement and eliminate the influence of slack due to its own weight, the arrangement interval of the cable support members is preferably 2 m or more and 6 m or less, and leakage occurs in the range of 2 m or more and 6 m or less. The bending angle of the coaxial cable can be appropriately adjusted in the range of 0.5 ° or more and 2 ° or less. At this time, the offset amount of the cable support member can be appropriately adjusted according to the cable arrangement interval and the bending angle.

The cable support member and the trough lid may be made of resin, and the cable support member may be formed integrally or separately from the trough body made of resin. If the trough body and the cable support member are integrally formed, the work of fixing the cable support member to the trough body becomes unnecessary. As the resin used for the trough body and the trough lid, it is desirable to use a polyolefin resin which is hydrophobic and has a low water absorption rate. Further, as the polyolefin resin, it is desirable to use a recycled polyolefin resin in consideration of environmental consideration and cost reduction. Even if a recycled polyolefin resin is used, it can be used as a trough structural member, and telecommunications characteristics can be satisfied.

On the other hand, when the trough body and the cable support member are provided separately, it is necessary to fix the cable support member at a predetermined position on the bottom of the trough body. In this case, by forming a fixing portion inside the cross section of the trough body and fixing the cable supporting member to the fixing portion, the cable supporting member can be reliably arranged at a predetermined position and the cable can be easily arranged. The support member can be fixed to the trough body.

For example, by forming inner ribs facing each other on the inner side surface and inner bottom surface of the trough body to form a fixing portion and arranging a cable support member between the inner ribs, the cable support member can be easily fixed to the trough body. can do. Therefore, the cable support member can be fixed at a predetermined position on the trough body without the need for a separate fixing bolt or the like.

Further, the cable support member formed by arranging the support portion of the cable support member offset from the center portion of the cross section of the cable support member is provided so that the offset positions are alternately offset from the center of the cross section of the trough structure in the longitudinal direction. By reversing the cables so as to be opposite to each other and arranging them on the inner ribs at predetermined intervals, offset arrangement in a predetermined cycle in the trough length direction of the leaky coaxial cable becomes possible. The bending angle of the leaking coaxial cable in the S-shaped arrangement of the leaking coaxial cable of the cable support member is preferably 2 ° or less, and if it is 0.5 ° or less, the bending angle is small and no effect can be expected. It is desirable that it is 0.5 ° or more and 2 ° or less. Further, in the case of the S-shaped arrangement, in order to adjust the extra length of the S-shaped arrangement, tension may be applied to the leaky coaxial cable as necessary.

Further, by fixing the leaky coaxial cable to the cable support member with a string-shaped fixing member, it is possible to prevent the leaky coaxial cable from being displaced from the support portion of the cable support member in the event of an earthquake or the like. Further, by increasing the tightening force of the string-shaped fixing member for fixing the leaky coaxial cable, the leaky coaxial cable can be stably fixed. Here, it is desirable that the tightening force of the string-shaped fixing member is usually a tightening force within a range in which the cross-sectional deformation of the leaky coaxial cable does not occur. Further, when the leaky coaxial cable described later is not pressed by the pressing body, the tightening force of the string-shaped fixing member can be applied within the range of the cross-sectional deformation distortion rate of the leaky coaxial cable of 0.2%.
At this time, the reason why it is necessary to set a restriction so that the tightening force of the string-shaped fixing member is applied within the range of 0.2% of the cross-sectional deformation distortion rate of the leaky coaxial cable is as follows. In each cross section of the resin insulator string provided on the outer circumference of the inner conductor, the insulator string is spirally wound around the outer circumference of the inner conductor so as to face toward the center, and inside the cable, the inner conductor is wound. It has a cross-sectional structure in which a hollow portion is formed. For this reason, the rigidity of the cross section of the cable is lower than that of a power cable or the like in which the outer circumference of a normal conductor is entirely covered with an insulator.

Further, by pressing the leaky coaxial cable with the pressing body, a pressing force can be applied to the leaky coaxial cable within the range where the cross-sectional deformation distortion rate of the leaky coaxial cable is 0.2%. Therefore, a frictional force can be applied to the leaky coaxial cable by the contact between the leaky coaxial cable and the pressing body, and the resistance to expansion and contraction in the cable axial direction due to thermal expansion and contraction of the leaky coaxial cable and the resistance to pulling out from the outside are increased. be able to. As a result, expansion and contraction of the leaky coaxial cable in the cable axial direction due to thermal expansion and contraction is suppressed, and it becomes difficult to pull out the leaky coaxial cable in one direction from the inside of the trough. Therefore, it is possible to alleviate the dimensional change due to thermal expansion of the leaky coaxial cable and prevent the leaky coaxial cable from being stolen. In this way, by adding the cross-sectional deformation distortion rate of the leaky coaxial cable within the range of 0.2%, it is possible to prevent creep deformation of the cross-section of the leaky coaxial cable due to pressing. As a result, it is possible to suppress deformation of the cable cross section and dimensional change in the cable axial direction in the longitudinal direction, and at the same time, maintain the long-term durability of the cable itself. Further, when a pulling force acts on the leaking coaxial cable, even if the cross-sectional deformation distortion of the leaking coaxial cable is suppressed within a predetermined range, the pulling force of the cable per predetermined length, for example, 100 m of cable length, should be 300 kg or more. And the anti-theft effect can be obtained.

Further, by fixing the trough body to the concrete ground with anchor bolts, the trough body is directly fixed to the concrete ground, so that the trough body does not move even in the event of an earthquake or the like. Further, even in this case, since the top of the anchor bolt and the bottom of the leaky coaxial cable are arranged at a predetermined distance from each other, they do not interfere with each other. In addition, there is no need to arrange a separate support member for fixing the trough, an angle member, or the like. Further, since the angle member or the like is not used as the support member for fixing the trough, the influence of the electromagnetic wave by the angle member or the like can be suppressed.

Here, the trough fixing bolt insertion hole may be an existing slot-shaped insertion hole formed in the longitudinal direction and the width direction of the trough body substantially in the center in the longitudinal direction and the width direction of the trough body. Trough fixing bolt insertion holes may be formed between the ribs having a predetermined length along the longitudinal direction and facing each other. When the rib is used, the rib can function as a guide when forming the fixing bolt insertion hole. By doing so, even if there is an error in the formation position of the anchor nut placed on the concrete ground, the formation position of the trough fixing bolt insertion hole has a degree of freedom along the rib, so it is possible to fix the trough. There is no problem. Here, even if the formation position of the anchor nut arranged on the concrete ground is displaced in the width direction of the trough body, the connection angle of the connection portion of the trough body can be adjusted at 4 ° or less. Therefore, the deviation of the formation position of the anchor nut can be dealt with by adjusting the connection angle of the connection portion of the trough body.

In addition, the leakage coaxial cable can control the amount of radio wave leakage (coupling loss) by designing the slot. Taking advantage of this characteristic, for example, by using a leaky coaxial cable designed so that the slot arrangement angle and density increase at predetermined intervals of the leaky coaxial cable as it approaches the final train point, a position far from the feeding point. As you go to, the coupling loss becomes smaller and the amount of radio wave leakage increases. Therefore, the relay interval can be increased and the range of the reception level can be increased as compared with the case of using a leakage coaxial cable having a constant coupling loss from the feeding point to a position far from the feeding point.

Further, by arranging the cable connection portion for connecting the leaky coaxial cables to each other at a position other than the arrangement portion of the cable support member in the trough structure, interference between the cable connection portion and the cable support member can be avoided. ..

Further, the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member inside the closed space inside the trough structure formed by connecting the trough with the trough lid covered to the trough main body. When the communication characteristic under the predetermined conditions in the 400 to 440 MHz band is that the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member arranged on the concrete ground without the presence of the trough structure. When compared with the above, it is possible to obtain a leaky coaxial cable laying structure that satisfies the communication characteristics in the range of the transmission loss within ± 1 dB / km and the coupling loss within ± 1 dB. Therefore, it is possible to satisfy the communication characteristics in the range where the transmission loss is within ± 2 dB / km and the coupling loss is within ± 2 dB.

Further, even when the outer surface and the inner surface of the trough structure are wetted with water to absorb water, the same communication characteristics as when the outer surface and the inner surface of the trough structure are in a dry state can be obtained. it can. That is, the transmission loss is ± 1 dB / km when compared with the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member whose height is adjusted on the concrete ground without the presence of the trough structure. It is possible to obtain a leaky coaxial cable laying structure having communication characteristics within ± 1 dB of coupling loss. Therefore, even in this case, it is possible to satisfy the communication characteristics in the range where the transmission loss is within ± 2 dB / km and the coupling loss is within ± 2 dB.

In this way, when the leaky coaxial cable is placed at a predetermined height on the cable support member inside the closed space of the resin trough structure, and when the leaky coaxial cable is not placed inside the trough structure. In comparison with the case where the leaky coaxial cable is placed at a predetermined height on the cable support member on the concrete ground, the transmission loss is within ± 1 dB / km and the coupling loss is within ± 1 dB in the above communication characteristic evaluation test. In order to satisfy the communication characteristics in the range of ± 2 dB / km, it is possible to satisfy the communication characteristics in the range of the transmission loss within ± 2 dB / km and the coupling loss within ± 2 dB. Furthermore, even when water is absorbed from the surface of the resin trough structure, the communication characteristics are compared with those when it is placed inside the dry resin trough structure, even though it contains inorganic substances. It can be seen that the communication characteristics do not change.

As the laying structure of the leaky coaxial cable of the trough structure satisfying the communication characteristics, a trough structure made of a polyolefin-based recycled resin is used, but a leaky coaxial cable laying structure using a polyolefin resin can also be used. By using the trough structure made of polyolefin-based recycled resin, it is possible to satisfy the communication characteristics in the range of the transmission loss within ± 1 dB / km and the bond loss within ± 1 dB. Therefore, it is possible to satisfy the communication characteristics in the range where the transmission loss is within ± 2 dB / km and the coupling loss is within ± 2 dB. The reason for this is considered to be that the polyolefin-based recycled resin is hydrophobic and has a remarkably low water absorption rate.

Further, the dielectric constant of the polyolefin-based recycled resin forming the trough structure at a frequency of 400 to 440 MHz measured by the capacitance method is 3.15 or less, and the trough lid constituting the trough body and the maximum wall of the trough body are formed. If the thickness is formed to be 10 mm or less, it is possible to obtain a laying structure of the leaky coaxial cable having excellent communication characteristics with the leaky coaxial cable inside the trough body.

In the second invention, a trough body made of resin having a bottom, a bottom, and side walls rising on both sides of the bottom and having a substantially U-shaped cross section is formed, and abbreviated in the longitudinal direction and the width direction of the trough body. An existing long hole-shaped trough fixing bolt insertion hole formed in the center in the longitudinal direction of the trough body, or a predetermined length along the trough longitudinal direction in the center of the back surface of the bottom surface in the width direction. Ribs facing each other are formed, and the trough body is fixed to the concrete ground by anchor bolts inserted into any of the trough fixing bolt insertion holes formed at any position in the groove between the ribs. This is a trough body that houses a leaky coaxial cable that can adjust the formation position of the trough fixing bolt insertion hole so as to correspond to the fixing position of the anchor bolt.

Further, as a fixing portion for fixing the cable support member inside the cross section of the trough body, the cable support member is inserted into the inner side surface and / or inner bottom surface of the trough body at a predetermined position in the longitudinal direction of the trough body. Internal ribs facing each other may be formed so that they can be fixed. At this time, it is desirable that the inner rib is not formed on the inner bottom surface of the trough, the inner rib is formed only on the inner side surface of the trough, and the groove for draining water is formed on the bottom of the cable support member. With such a structure, rainwater does not collect on the bottom of the trough.

Alternatively, a cable support member for supporting the leaky coaxial cable may be integrally formed with the trough body at a predetermined position in the longitudinal direction of the trough body inside the cross section of the trough body.

The trough body is covered with a resin trough lid, connecting portions are formed at one end and the other end of the trough body and the trough lid, and the trough lid is covered with the trough body. In this state, the trough bodies covered with a plurality of the trough lids may be connected by connecting the respective connection portions.

It is desirable that the trough body is made of a polyolefin resin-based material containing an inorganic substance, and the dielectric constant in the 400 to 440 MHz band measured by the capacitance method of the trough body is 3.15 or less. Since the dielectric property of the polyolefin resin deteriorates due to the inclusion of the inorganic substance, it is necessary to confirm whether the content of the inorganic substance is within the permissible range. Here, the dielectric constant of polyethylene in the 400 to 440 MHz band measured by the capacitance method is 2.35, and the dielectric constant of polypropylene is 2.65, but the dielectric constant of the polyolefin-based recycled resin is 3. Satisfying 15 or less and containing an inorganic substance increases the dielectric constant but does not lead to an extreme increase.

The trough body may be formed of a material having a tensile strength of 20 MPa or more and a flexural modulus of 1000 MPa or more as mechanical properties.

The trough body may be formed of a material having ^{a Charpy impact value of 5 kJ / m 2} or more obtained by a Charpy impact test based on JIS K7110 as a mechanical property.

The trough body may be formed of a material having a water absorption rate of 0.15% or less after water absorption at 23 ° C. for 24 hours, which is measured based on JIS K7209 equivalent to ASTM D570.

_{In addition, the trough body is immersed in a 3% NaCl aqueous solution which is a seawater simulated liquid, a 30% CaCl 2} immersion test as a snow melting agent simulated liquid, and a test in which the trough body is immersed for 24 hours at room temperature in accordance with JIS K7114. _{In the immersion test with a test solution obtained by diluting a liquid obtained by mixing H 2} SO ₄ and _{H NO 3} as an acidic rain simulation solution at a ratio of 2: 1 to a concentration of 1%, the mass change rate was 0 in all the tests. It may be formed from a material that is less than or equal to 1%.

Further, the polyolefin-based recycled resin containing an inorganic substance forming the trough body is subjected to ultraviolet light having an irradiation intensity of ^{90 mW / cm 2 for 2000 hours in an environment of 50% humidity, and has a tensile strength after a weather resistance acceleration test.} The residual ratio of the Charpy impact value after the same ultraviolet irradiation is preferably 95% or more of the tensile strength before the ultraviolet light irradiation, and the residual ratio of the Charpy impact value after the same ultraviolet light irradiation is preferably 90% or more of the Charpy impact value before the ultraviolet light irradiation. ..

Good communication characteristics can be ensured by forming the trough body with a material having a dielectric constant of 3.15 or less in the 400 to 440 MHz band. Further, by setting the tensile strength of the trough body to 20 MPa or more and the flexural modulus of 1000 MPa or more, the material strength required for the trough body is satisfied, and the Charpy impact value is 5 kJ / m ² or more. , Practically sufficient mechanical properties can be satisfied.

The trough body for the leaky coaxial cable and the trough lid can be formed by using a polyolefin resin, but it is preferable to form them by using a polyolefin-based recycled resin. For example, by forming the trough body with a polyolefin-based recycled resin, not only the strength required for practical use is satisfied, but also the corrosion resistance confirmation test such as the seawater mock test, the snow melting agent mock test, and the acid rain mock test, and the weather resistance promotion test. Also shows excellent corrosion resistance and weather resistance. For this reason, it is possible to consider the environment and reduce costs, and at the same time, the long-term durability of the trough is guaranteed. Although the tensile strength, flexural modulus, Charpy impact value, water absorption rate, corrosion resistance, weather resistance, etc. of the trough body have been described in the paragraphs 1981 to 0085, the trough lid is also made of the same polyolefin as the trough body. If a system recycled material is used, similar characteristics such as tensile strength, flexural modulus, Charpy impact value, water absorption rate, corrosion resistance, and weather resistance can be obtained. Similar inventions can be obtained for the characteristics of the trough lid.

Further, as will be described later, when a trough structure formed of a polyolefin-based recycled resin having a dielectric constant of 3.15 or less is used, a transmission loss is observed in a test for confirming communication characteristics in the 400 to 440 MHz band. The characteristics of the bond loss should be almost the same as when placed directly on concrete ground without using a resin trough, and the difference between the average values of transmission loss and bond loss should be within ± 1 dB / km and ± 1 dB or less, respectively. Can be done. Therefore, it is possible to satisfy the communication characteristics in the range where the transmission loss and the coupling loss are within ± 2 dB / km and within ± 2 dB, respectively. Further, as described above, since the trough body and the trough lid constituting the trough structure have low water absorption rates, stable communication characteristics can be obtained even when wet with rainwater or the like. Therefore, the water absorption rate of the material forming the trough structure as well as the dielectric constant of the material forming the trough is an important property in maintaining the telecommunications characteristics.

The third invention is a polyolefin-based recycled resin material containing an inorganic substance, which contains at least magnesium hydroxide and titanium oxide as inorganic substances and has a dielectric constant of 3.15 or less, and the magnesium hydroxide content is the polyolefin-based material. It is a polyolefin-based recycled resin material having excellent flame retardancy and communication characteristics, which is 18% by mass or more with respect to the total mass of the recycled resin material.

Here, in the present invention, since transmission / reception is performed from a leaky coaxial cable arranged in the trough, a polyolefin resin material having a dielectric constant as a predetermined value is required in order to secure flame retardancy and telecommunications characteristics. Therefore, a polyolefin resin containing an inorganic substance having flame retardancy and telecommunications characteristics is required. Magnesium hydroxide is added as a flame retardant and titanium oxide is added as an ultraviolet absorber to ensure flame retardancy and weather resistance of the polyolefin resin. However, since the dielectric constant increases due to the addition of an inorganic substance, the addition of an inorganic substance is used. It is possible to obtain a polyolefin-based recycled resin containing an inorganic substance in which the increase in dielectric constant is suppressed to 3.15 or less, which is a predetermined value or less. Furthermore, by using this material, it is possible to obtain a polyolefin-based recycled resin material that can prevent deterioration of telecommunications characteristics and impact characteristics due to an increase in the content of inorganic substances in addition to flame retardancy and weather resistance. it can.

There are three types of polyolefin-based recycled resin materials containing the inorganic substances, magnesium hydroxide, calcium carbonate, and titanium oxide, and the content ratio of each of the inorganic substances to the total mass of the polyolefin-based recycled resin is magnesium hydroxide 18 to 21.3. It is contained in the range of mass%, calcium carbonate 14 to 16.5 mass%, and titanium oxide 2 to 2.2 mass%, and the total content of the inorganic substances is 34 mass% or more and 40 mass% or more of the total mass of the polyolefin-based recycled resin. It is desirable that it is mass% or less.

By adopting the above composition, the dielectric constant is set to a predetermined value or less, and the balance between water absorption, corrosion resistance, flame retardancy and weather resistance is improved without deteriorating the strength and impact characteristics. Can be done. In particular, by setting magnesium hydroxide, calcium carbonate, and titanium oxide in the above-mentioned amounts, the dielectric constant, flame retardancy, and weather resistance can be optimized.

In the polyolefin-based recycled resin material, a virgin resin may be used as the polyolefin resin instead of the polyolefin-based recycled resin. Even in the case of a virgin material, if the composition is the same, similar telecommunications characteristics and mechanical characteristics can be obtained.

The polyolefin-based recycled resin material may be a material for a structure or a member for telecommunications.

Since the polyolefin-based recycled resin material can have a dielectric constant of a predetermined value or less, good telecommunications characteristics can be obtained, and further, since it has a predetermined strength, it can be used as a structure or member for telecommunications. Can be used.

Specifically, the polyolefin-based recycled resin material is excellent in flame retardancy, and at the same time, by setting the dielectric constant to 3.15 or less, good telecommunications characteristics can be obtained. Further, since it has a predetermined strength, for example, a tensile strength of 20 MPa or more, it is suitable for use in a structure or member for telecommunications.

A fourth invention is a method for using a polyolefin-based recycled resin, which comprises using the polyolefin-based recycled resin material according to the third invention for a trough structure.

As described above, since the polyolefin-based recycled resin material can be used for structures and members for telecommunications, it can be used for a trough body and a trough lid for accommodating a leaky coaxial cable. Therefore, it is possible to provide a method of using the polyolefin-based recycled resin used for the trough structure using the polyolefin-based recycled resin material.

A fifth invention is a method of laying a leaky coaxial cable, in which a resin trough body having a bottom portion and side wall portions standing on both sides of the bottom portion and having a substantially U-shaped cross section is fixed to concrete ground. The concrete ground is provided with a step of arranging a cable support member inside the trough main body and a step of arranging a leaky coaxial cable with the support wire facing downward on the support portion of the cable support member. In the step of fixing to, an existing long hole-shaped insertion hole formed in the longitudinal direction and the width direction of the trough body in the longitudinal direction and the width direction of the trough body, or the width direction of the back surface of the bottom surface. Leakage characterized in that the trough is fixed to the concrete ground by inserting an anchor bolt into any of the insertion holes formed between the ribs facing each other having a predetermined length along the longitudinal direction of the trough in the center. This is a method of laying a coaxial cable.

Further, in the step of fixing the trough body to the concrete ground, connecting portions are formed at one end and the other end of the trough body, and the connecting portions are connected by tilting each other at a predetermined angle. Therefore, it may be a laying method capable of laying so as to absorb the misalignment of the formation position of the anchor nut provided on the concrete ground. By doing so, even if the formation position of the anchor nut arranged on the concrete ground deviates in the width direction of the trough body, the connection angle of the trough connection portion can be adjusted in the longitudinal direction of the formation position of the anchor nut. It is possible to deal with not only the misalignment of the above but also the misalignment in the width direction.

In the step of arranging the cable support member inside the trough main body and arranging the leaky coaxial cable in the support portion of the cable support member with the support wire facing downward, the cable support member is the cable support. The step of arranging the leaky coaxial cable in a substantially S shape by forming the support portion of the member at a predetermined distance offset from the center of the cable support member and arranging the adjacent cable support members by alternately inverting them. It may be a method of laying a leaky coaxial cable characterized by including.

By alternately arranging the cable support members at a predetermined distance offset, the leaky coaxial cable may be arranged in a substantially S shape. As described above, since the leaky coaxial cable can be arranged in an S shape on the cable support member, the stress applied to the cable in the event of an earthquake or the like can be relaxed and the leaky coaxial cable can be prevented from being deformed.

Further, by arranging a resin trough lid on the upper part of the trough body and closing the trough, a polyethylene foam sheet or rubber molding is performed on at least a part of the support portion of the cable support member on which the leaky coaxial cable is placed. There may be a step of pressing the leaky coaxial cable by a pressing body made of any of the bodies. By applying the pressing force at this time within the range where the cross-sectional deformation distortion rate of the leaky coaxial cable is within the range of 0.2%, the position of the cable does not shift unless a pulling force of 300 kg or more is applied per 100 m of the leaky coaxial cable. As such, a laying method for laying a leaky coaxial cable can be provided. This makes it possible to make the laying method effective not only for preventing expansion and contraction due to changes in the environmental temperature but also for preventing theft of cables.

According to the fifth invention, since the leaky coaxial cable can be laid only by arranging the leaky coaxial cable on the cable support member arranged inside the trough body, no other fixing member or gripping member is required. Therefore, the leaky coaxial cable can be easily laid.

In particular, when closing the trough lid, pressing the leaky coaxial cable with a pressing body can apply pressing force to the leaky coaxial cable, and resistance to expansion and contraction in the cable axial direction due to thermal expansion and contraction of the leaky coaxial cable and external The pull-out resistance from the cable can be increased. As a result, it is possible to relax the expansion and contraction in the cable axial direction and make it difficult to pull out the leaky coaxial cable from the inside of the trough in one direction.

A sixth invention is a polyolefin-based recycling of a resin material containing an inorganic substance constituting a trough structure having a dielectric constant of 3.15 or less in the frequency 400 to 440 MHz band in the laying structure of the leaky coaxial cable according to the first invention. A leaky coaxial cable laying structure that is made of resin and is characterized in that communication is performed in the frequency band of the 400 MHz band between the leaky coaxial cable mounted inside the trough structure and the on-vehicle antenna of the train. This is the communication method used.

According to the polyolefin-based recycled resin containing the above-mentioned inorganic substances, since it has good communication characteristics, between the leaky coaxial cable arranged inside the trough structure arranged substantially parallel to the train track and the antenna on the train vehicle. It can be expected that a good communication state can be secured.

The transmission loss is ± 2 dB / km as compared with the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member whose height is adjusted on the concrete ground without using the trough structure. It is desirable that it is possible to obtain communication characteristics within the range of within ± 2 dB of coupling loss.

The seventh invention uses the leaky coaxial cable laying structure according to the first invention, and the resin material containing an inorganic substance constituting the trough structure in the leaky coaxial cable laying structure has a dielectric constant in the frequency 400 to 440 MHz band. Is a polyolefin-based recycled resin having a dielectric constant of 3.15 or less, and a frequency band of 400 MHz band between the leaky coaxial cable mounted inside the trough structure having a dielectric constant of 3.15 or less and the on-vehicle antenna of the train. It is a communication system using a leaky coaxial cable laying structure, which is characterized in that communication is performed by.

The transmission loss is ± 2 dB / km as compared with the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member whose height is adjusted on the concrete ground without using the trough structure. It is desirable that it is possible to obtain communication characteristics within the range of within ± 2 dB of coupling loss.

Further, since the maximum wall thickness of the trough lid and the trough body used for the laying structure of the leaky coaxial cable is formed to be 10 mm or less, the dielectric constant is higher than that of a concrete trough or the like. It is possible to keep both the maximum thickness of the wall portion of the trough structure low, and good communication characteristics can be obtained between the leaky coaxial cable in the trough structure and the on-vehicle antenna on the train.

Further, if the resin material constituting the trough structure in the laying structure of the leaky coaxial cable is a polyolefin-based recycled resin containing an inorganic substance having a dielectric constant of 3.15 or less in the frequency 400 to 440 MHz band, it is placed inside the trough structure. Communication can be performed in the frequency band of the 400 MHz band between the installed leaky coaxial cable and the on-board antenna of the train. At this time, since the trough structure has a predetermined tensile strength of 20 MPa or more and a flexural modulus of 1000 MPa or more, it goes without saying that the trough structure satisfies the strength required for the members constituting the communication system.

According to the present invention, the height and orientation of the slot can be kept constant, and the influence of wind from a train or the like and the influence of water wetting or pollution can be suppressed, and changes in environmental temperature and ultraviolet rays can be suppressed. Leaky coaxial cable laying structure that can alleviate the deterioration of the cable due to irradiation and does not exceed the maximum bending radius of the leaky coaxial cable, the method of laying the leaky coaxial cable, the trough body for the leaky coaxial cable, and flame retardancy and electricity. It is possible to realize a polyolefin-based resin material having excellent communication characteristics, a method of using the material for a trough structure, a communication method using a laying structure of a leaky coaxial cable, and a communication system. In particular, since the trough structure of the leakage cable having a dielectric constant of a predetermined value or less has been realized, good communication with the on-vehicle antenna can be performed by using the above communication method and communication system. Further, in the laying structure of the leaky coaxial cable of the present invention, a trough having excellent linearity made of a material having excellent bending rigidity is used as compared with the protective member of the corrugated structure, so that the leaky coaxial cable has high rigidity and excellent linear workability. Can realize the laying structure of.

An exploded perspective view showing a leaky coaxial cable laying structure 1. The assembly perspective view which shows the leakage coaxial cable laying structure 1. The assembly perspective view which shows the leakage coaxial cable laying structure 1a. The perspective view which shows the leakage coaxial cable 5. FIG. 5 is a cross-sectional view showing a leaky coaxial cable 5. The conceptual diagram which shows the arrangement of the slot 23 of the leakage coaxial cable 5. The perspective view of the cable support member 11. The figure which shows the process of arranging the leakage coaxial cable 5 on the cable support member 11. Sectional drawing of trough main body 3a. FIG. 7A is an enlarged view of part B. FIG. 5 is a cross-sectional view showing a trough fixing bolt insertion hole 41. The figure which shows the state which the trough main body 3a is fixed to the concrete ground 35 by the anchor bolt 43. Top view of the trough body 3a. Bottom view of the trough body 3a. The figure which shows the process of arranging the cable support member 11 on the trough main body 3a. The figure which shows the state which arranged the cable support member 11 on the trough main body 3a. Partial plan view of the trough body 3a according to another embodiment. It is sectional drawing of the trough main body 3a which concerns on another embodiment, and is the sectional view taken along line FF of FIG. The cross-sectional view which shows the leakage coaxial cable laying structure 1. The cross-sectional view which shows the leakage coaxial cable laying structure 1b. An example of a plan conceptual diagram of a leaky coaxial cable laying structure 1. The perspective view of the cable support member 11a. The front view of the cable support member 11a. An example of a plan conceptual diagram of a leaky coaxial cable laying structure 1c. The perspective view of the cable support member 11b. The figure which shows the state which arranged the leakage coaxial cable 5 on the cable support member 11b. The front view which shows the state before closing the trough lid 3b of the leakage coaxial cable laying structure 1d. The front view which shows the leakage coaxial cable laying structure 1d. The front view which shows the state before closing the trough lid 3b of the leakage coaxial cable laying structure 1e. The front view which shows the leakage coaxial cable laying structure 1e.

[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing a leaky coaxial cable laying structure 1 according to the present invention, and FIG. 2 is an assembly perspective view showing a leaky coaxial cable laying structure 1.

The trough 3 for the leaky coaxial cable mainly includes a trough body 3a and a trough lid 3b. The trough body 3a and the trough lid 3b are made of resin and are molded by press molding or injection molding. As the material of the trough body 3a and the trough lid 3b, for example, a recycled resin having high strength, high corrosion resistance, and high weather resistance (for example, a resin composition composed of polyethylene, polypropylene, etc. and a flame-retardant material) can be used. .. The trough body 3a and the trough lid 3b are usually about 1 m in length. Strictly speaking, the length of the trough body 3a and the trough lid 3b is set to be slightly longer than 1 m, and when adjacent troughs 3 are connected, the length is approximately 1 m when the overlapping lengths are subtracted at the time of connection. good.

Connecting portions 13a and 13b are provided at one end and the other end of the trough body 3a and the trough lid 3b in the longitudinal direction, respectively. The connecting portion 13a has a concave groove on the inner surface side of the trough main body 3a, and the connecting portion 13b has a protrusion corresponding to the concave groove on the outer surface side of the trough main body 3a. Therefore, the troughs 3 can be connected to each other by connecting the connecting portion 13a of one trough main body 3a and the connecting portion 13b of another adjacent trough main body 3a to each other.

As in the leakage coaxial cable laying structure 1a shown in FIG. 3, the trough 3 may not have a connecting portion at at least one end. When a plurality of such troughs are arranged consecutively, a predetermined number of troughs 3 adjacent to each other may be connected to each other. In addition, a structure in which a plurality of troughs 3 having a trough lid 3b covered with a trough body 3a are connected to each other is referred to as a trough structure. In the following description, the leaky coaxial cable laying structure 1 having the connecting portions 13a and 13b will be described, but the same applies to the leaky coaxial cable laying structure 1a.

The trough body 3a is composed of a bottom portion 7 and side wall portions 9 that stand up substantially at right angles to both sides of the bottom portion 7. That is, the trough body 3a has a substantially U-shaped cross section. Fixing brackets 15 are attached to the upper portions of the side wall portions 9 near both ends of the trough main body 3a. A nut is fixed to the fixing bracket 15.

On the other hand, the trough lid 3b is arranged on the trough main body 3a and closes the upper part of the trough main body 3a. An insertion hole for a bolt is provided at a predetermined position of the trough lid 3b. By closing the trough lid 3b and screwing the bolt 17 into the fixing bracket 15 from above the trough lid 3b, the trough lid 3b is screwed into the trough body 3a. Can be fixed to. The fixing of the trough lid 3b and the trough main body 3a is not limited to this embodiment, but it is better that the trough lid 3b is covered with metal parts such as fixing brackets as few parts as possible.

The leaky coaxial cable 5 is housed inside the trough main body 3a. The structure of the leaky coaxial cable 5 will be described below. FIG. 4A is a perspective view showing the leaky coaxial cable 5, and FIG. 4B is a cross-sectional view showing the leaky coaxial cable 5. The leaky coaxial cable 5 is mainly formed from the inner conductor 19, the insulator 21 including the insulator string 21a, the outer conductor 25, the slots 23 provided in the outer conductor 25, the outer sheath 27, the support wire 29, and the like, in order from the inner side. It is composed.

The inner conductor 19 is made of, for example, aluminum or copper, and a hollow pipe-shaped conductor as shown in the figure can be used. An insulator 21 including a spiral insulator string 21a is arranged on the outer periphery of the inner conductor 19. The insulator 21 is formed over substantially the entire length of the inner conductor 19. The insulator 21 is formed of a stable and good insulating resin such as a polyethylene resin or a fluororesin. Instead of the insulator 21 including the insulator string 21a, a solid resin, a foamed resin, or a resin sheet member may be spirally wound in the cable axial direction.

An outer conductor 25 is provided on the outer periphery of the insulator 21. The outer conductor 25 is, for example, a straight pipe or a corrugated pipe made of aluminum or copper. A plurality of slots 23 are provided in the outer conductor 25 at predetermined intervals. The slot 23 is formed, for example, in the shape of an elongated hole having an inclination angle with respect to the longitudinal direction of the leaky coaxial cable 5. The slot 23 imparts a function peculiar to the leaky coaxial cable, which is to transfer electromagnetic energy between the inside and the outside of the leaky coaxial cable 5.

FIG. 5 is a conceptual diagram showing the arrangement of slots 23 in the leaky coaxial cable 5. The leaky coaxial cable 5 is used by connecting a plurality of leaky coaxial cables 5 to each other. Between the cable connection portion 31 between the leaky coaxial cables 5 and the terminal connection portion 32, the farther the distance from the feeding point (feeding portion 34) is, the more the arrangement angle of the slot 23 of the leaking coaxial cable 5 is in the cable axial direction. It is arranged so as to be larger than the other. Alternatively, the slots 23 may be arranged at smaller intervals so that the slot 23 becomes denser as the distance from the feeding point (feeding unit 34) increases.

An outer sheath 27 is provided on the outer circumference of the outer conductor 25. The outer sheath 27 is provided so as to cover the outer circumference of the outer conductor 25, and is integrally formed with the support wire 29 via the neck portion. That is, the support wire 29 is covered with the outer sheath 27 and is arranged so as to face each other at a predetermined distance from the outer conductor 25. The support wire 29 is made of, for example, a steel wire or the like. The support wire 29 is generally provided for the purpose of preventing expansion and contraction of the leaky coaxial cable 5 due to changes in the environmental temperature and slackening due to its own weight to impart dimensional stability of the leaky coaxial cable 5, but the leaky coaxial cable 5 is provided. This is the part used when hanging the cable on a wall surface or the like. In the illustrated example, the slot 23 is arranged on the side substantially opposite to the support line 29. The slot 23 may be provided at a position opposite to the support line 29 of the outer conductor 25, or may be arranged so as to have a predetermined angle from the opposite position.

As shown in FIG. 1, the cable support member 11 is arranged at a predetermined position in the longitudinal direction inside the trough main body 3a. FIG. 6A is a perspective view showing the cable support member 11. The cable support member 11 is made of resin and / or rubber, and is made of, for example, the same material as the trough 3. The cable support member 11 has an outer shape corresponding to the internal shape of the trough main body 3a, and the support portion 33 is formed on the upper surface substantially at the center in the width direction. The support portion 33 is a concave portion having a substantially semicircular shape (substantially semicircular shape), and is provided so as to penetrate both sides of the cable support member 11. Further, a groove 33a for accommodating the support wire 29 of the leaky coaxial cable 5 is further formed in the substantially center of the support portion 33. Here, one or a plurality of grooves for draining water may be formed on the contact surface of the cable support member 11 with the trough bottom surface (upper surface) on the opposite side to the support portion forming surface, although not particularly shown. The shape of the groove for draining water is not particularly limited, but may be, for example, a groove on a semicircular arc.

FIG. 6B is a diagram showing a process of arranging the leaky coaxial cable 5 on the cable support member 11. A leaky coaxial cable 5 is placed on the support portion 33 of the cable support member 11 with the support wire 29 facing downward (arrow C in the figure). At this time, the support wire 29 is fitted into the groove 33a, and substantially half the circumference of the main body of the leaky coaxial cable 5 is supported by the support portion 33. That is, the support portion 33 of the cable support member 11 is formed in a shape capable of accommodating the leaky coaxial cable 5.

As described above, in the leaky coaxial cable laying structure 1, the trough body 3a is covered with the trough lid 3b, and inside the closed space formed by the trough 3, the trough 3 is made of resin and / or made of resin at a predetermined position in the longitudinal direction. Alternatively, a rubber cable support member 11 is arranged. Further, the leakage coaxial cable 5 is placed on the support portion 33 of the cable support member 11 so that the support wire 29 is directed downward and the support wire 29 is housed in the groove 33a.

Next, a method of laying the leaky coaxial cable will be described. First, the trough body 3a is fixed to the concrete ground. 7A to 7D are views showing a process of fixing the trough main body 3a to the concrete ground 35, FIG. 7A is a cross-sectional view showing a state in which the trough main body 3a is installed on the concrete ground 35, and FIG. 7B is FIG. 7A. It is an enlarged view of part B of.

On the back surface of the bottom portion 7 of the trough main body 3a, a pair of ribs 37 having a predetermined length are provided along the longitudinal direction of the trough main body 3a at substantially the center in the width direction of the trough main body 3a. A groove 39b is formed between the ribs 37 facing each other. Further, on the surface of the bottom portion 7 of the trough main body 3a, a groove 39a having a predetermined length is provided along the longitudinal direction of the trough main body 3a at a portion corresponding to the groove 39b.

As shown in FIG. 7C, a trough fixing bolt insertion hole 41 can be formed at any position in the longitudinal direction of the grooves 39a and 39b. As shown in FIG. 7D, the anchor nut 45 is embedded in the concrete ground 35 in advance, and the anchor nut 43 is inserted into the trough fixing bolt insertion hole 41 formed between the ribs 37 facing each other to form the anchor nut 45. Screw in. As described above, the trough body 3a can be fixed to the concrete ground 35. Here, the trough may be fixed to the concrete ground by fixing the anchor bolt to the ground and fixing the trough body 3a with a nut.

The trough fixing bolt insertion hole 41 may be formed in advance in the trough main body 3a. FIG. 8A is a plan view of the trough main body 3a, and FIG. 8B is a bottom view of the trough main body 3a. A long hole-shaped trough fixing bolt insertion hole 41 is formed at substantially the center of the trough main body 3a in the longitudinal direction and the width direction. By aligning the position where the anchor nut 45 is embedded in the concrete ground 35 with the position of the existing trough fixing bolt insertion hole 41, it is not necessary to newly form the trough fixing bolt insertion hole 41.

As described above, in the step of fixing the trough 3 to the concrete ground 35, the trough body 3a can be fixed to the concrete ground 35 by inserting the anchor bolt 43 into the trough fixing bolt insertion hole 41. At this time, the trough fixing bolt insertion hole 41 has an elongated hole shape (for example, substantially rectangular shape or oval shape) formed substantially in the center of the trough body 3a in the longitudinal direction and the width direction toward the longitudinal direction of the trough body. The existing one may be used. Alternatively, it may be formed at any position of a groove formed between the ribs 37 facing each other having a predetermined length along the longitudinal direction of the trough 3 at the center of the back surface of the bottom portion 7 in the width direction. Here, the oval is a figure in which both ends on the short side of the oval are formed in an arc shape toward the outside.

As described above, the existing trough fixing bolt insertion hole 41 formed in the trough main body 3a is an elongated hole elongated by a predetermined dimension in the trough longitudinal direction. Further, a trough fixing bolt insertion hole 41 can be formed at an arbitrary position in the grooves 39a and 39b of the trough body 3a. Therefore, it is possible to adjust the formation position of the trough fixing bolt insertion hole 41 so as to correspond to the fixing position of the anchor bolt 43 (the position where the anchor nut 45 is embedded).

Further, although not particularly shown, when the trough main body 3a is fixed to the concrete ground, connecting portions 13a and 13b are formed at one end and the other end of the trough main body 3a, respectively, and the connecting portions 13a and 13b, respectively. Can be connected by tilting each other at a predetermined angle. Needless to say, by doing so, it is possible to absorb the misalignment of the forming position of the anchor nut provided on the concrete ground.
As described above, as the adjustment of the fixing position of the anchor nut, by adjusting the connection angle of the connection portions 13a and 13b of the trough body 3a to at least one of the left-right direction and the up-down direction, the trough fixing bolt insertion hole 41 In addition to adjusting the distance between the formation positions of the trough body in the longitudinal direction, it is possible to adjust both the displacement of the fixed position of the trough body in the width direction of the trough body.

Next, the cable support member 11 is arranged inside the trough body 3a. FIG. 9A is a diagram showing a process of arranging the cable support member 11 inside the trough main body 3a, and FIG. 9B is a diagram showing a state in which the cable support member 11 is arranged at a predetermined position of the trough main body 3a.

As described above, the cable support member 11 is formed separately from the trough body 3a. The cable support member 11 is fixed to a fixing portion 49 formed inside the cross section of the trough body 3a. The fixing portion 49 is formed by the opposing inner ribs 47a formed on the inner side surface of the trough body 3a and the facing inner ribs 47b formed on the inner bottom surface so that the cable support member 11 can be inserted and fixed. It is composed. The cable support member 11 is inserted and fixed between the inner ribs 47a and 47b (arrow D in FIG. 9A).

By doing so, the installation position of the cable support member 11 can be easily grasped, and the cable support member 11 can be fixed to the trough body 3a simply by inserting it between the inner ribs 47a and 47b, so that the work is easy. Is. Both the mutually opposed inner ribs 47a formed on the inner side surface and the mutually facing inner ribs 47b formed on the inner bottom surface may be formed, or only one of them may be formed. Good. However, it is desirable that only the inner ribs 47a facing each other are formed on the inner side surface of the trough body 3a, and the inner ribs 47b are not formed on the inner bottom surface. As described above, when the inner rib 47a is formed only on the inner side surface of the trough body 3a, the cable support member 11 is inserted between the inner ribs 47a, and is fixed only by the inner rib 47a, the bottom surface is used for draining water. It is desirable to use a cable support member in which the groove is formed.

In this case, even if rainwater invades the inside of the trough main body 3a for some reason, the infiltrated rainwater is not blocked by the inner rib 47b of the trough main body 3a. The drainage groove formed on the bottom surface of the cable support member 11 forms a flow path on the inner bottom surface of the trough body 3a, and directs the water accumulated on the bottom of the trough body 3a toward the connection portion of the trough body 3a. This is because it can be flushed out. As a result, even if rainwater collects on the inner bottom surface of the trough main body 3a, it is possible to reduce the influence of the electromagnetic waves emitted from the leaky coaxial cable 5 on the electromagnetic wave characteristics such as reflection and absorption by the rainwater.

Next, the leaky coaxial cable 5 is arranged on the support portion 33 of the cable support member 11 arranged inside the trough main body 3a with the support wire 29 facing downward. Finally, by arranging the trough lid 3b on the trough body 3a and fixing it with bolts 17 (see FIG. 2), the leaky coaxial cable laying structure 1 is formed.

The cable support member 11 may be formed integrally with the trough main body 3a instead of being a separate body. 10A is a partial plan view of the trough main body 3a in which the cable support member 11 is integrally formed, and FIG. 10B is a sectional view taken along line FF of FIG. 10A.

In the embodiment shown in FIGS. 10A and 10B, the cable support member 11 is formed integrally with the resin trough body 3a. Therefore, the trough body 3a does not need a fixing portion for fixing the cable support member 11. As described above, the cable support member 11 may be formed integrally with the resin trough main body 3a, or may be formed separately. In the following description, an example in which the cable support member 11 is formed separately from the trough main body 3a will be described, but the same applies to the case where the cable support member 11 is integrally formed.

FIG. 11 is a front view of the leaky coaxial cable laying structure 1. The cable support member 11 allows the leaky coaxial cable 5 to be arranged at a predetermined height from the bottom 7 of the trough body 3a. Here, as described above, the leakage coaxial cable 5 has a slot 23 formed on the opposite side of the support line 29. Therefore, the slot 23 of the leaky coaxial cable 5 is arranged so as to be substantially upward.

In the figure, E is a range in which the center position of the slot 23 is arranged. In this way, the cable support member 11 can support the leaky coaxial cable 5 so that the slot 23 of the leaky coaxial cable 5 is at a predetermined angle at a predetermined height from the bottom 7 of the trough main body 3a.

The arrangement of the leaky coaxial cable 5 is not limited to the example shown in FIG. For example, as in the leaky coaxial cable laying structure 1b shown in FIG. 12, the support line 29 of the leaky coaxial cable 5 does not have to be arranged so as to face directly downward. In this case, the groove 33a of the cable support member 11 may be formed diagonally. By doing so, the range E of the center position of the slot 23 can be oriented obliquely at a predetermined angle.

FIG. 13 is an example of a plan conceptual diagram of the leaky coaxial cable laying structure 1 (however, the illustration of the trough lid 3b is omitted). As described above, the plurality of cable support members 11 are arranged at predetermined positions of the trough structure 51 in which the plurality of troughs 3 are connected at predetermined intervals. The leaky coaxial cable 5 is placed on a support portion 33 formed at a predetermined height of the cable support member 11 inside the closed space formed by the trough structure 51.

Here, as described above, the leaky coaxial cables 5 are connected to each other by the cable connecting portion 31. At this time, the cable connection portion 31 is arranged at a position other than the arrangement portion of the cable support member 11 in the trough structure 51. Therefore, the cable connecting portion 31 and the cable supporting member 11 do not interfere with each other.

Further, the length of the trough main body 3a and the trough lid 3b that normally constitute the trough structure is 1 m, and the cable support member 11 can be provided at a predetermined position with respect to a predetermined position in the longitudinal direction of the trough structure 51. For example, it can be set at intervals of 1 m or more and 6 m or less, and it is desirable that the intervals are set at intervals of 2 m or more and 6 m or less (G in the figure). By supporting the cables at intervals of 6 m or less, it is possible to prevent the cable support members 11 from loosening due to their own weight and to stably and reliably support the leaky coaxial cable. Further, by providing the cable support members 11 at intervals of 2 m or more, it is possible to prevent the cable support members 11 from loosening due to their own weight and to suppress the number of installed cable support members 11, so that the leakage coaxial cable is 2 m or more. It is desirable to support at intervals.

Even if the length of the trough body 3a and the trough lid 3b is not 1 m, the above effect can be obtained by providing the cable support member 11 at an interval of 2 m or more and 6 m or less. Here, the cable support member 11 is formed at a predetermined position of the trough 3. Therefore, when a trough 3 having a length of 1 m is used, it is necessary that three troughs 3 are connected in order to make the distance between the cable support members 11 a predetermined length of 2 m. Further, in order to make the distance between the cable support members 11 a predetermined length of 5 m, it is necessary that six troughs 3 are connected to each other. When the length of the trough 3 is not 1 m, it may be appropriately combined according to the length of the trough 3.

Further, by providing the cable support members 11 at intervals of 6 m or less, it is possible to prevent the cable support members 11 from loosening between the cable support members 11 due to their own weight. Therefore, it is possible to suppress a change in the direction in which the electromagnetic wave is radiated from the slot 23 due to the looseness of the leaky coaxial cable 5 and enable stable transmission / reception. Further, due to the looseness of the leaky coaxial cable 5, the leaky coaxial cable 5 does not come into contact with the bottom 7 of the trough body 3a, and the leaky coaxial cable 5 is prevented from getting wet or damaged when rainwater enters the trough 3. be able to. Here, when the cable support member 11 is integrally molded with the trough body 3a, the trough body 3a with the cable support member 11 integrally molded and the trough body 3a not integrally molded are combined to form a trough structure. The body 51 may be formed.

As described above, according to the present embodiment, since the leaky coaxial cable 5 is housed in the trough 3, the leaky coaxial cable 5 is not directly affected by rain or wind pressure from the train. , The communication characteristics of the leaky coaxial cable 5 can be stabilized. Therefore, the laid state of the leaky coaxial cable 5 can be stably maintained for a long period of time. Further, unlike the hanging type, there is no need for a support or a fixing jig for suspending the leaky coaxial cable 5. Further, since the leaky coaxial cable 5 is installed in the trough 3, it is possible to alleviate changes in the external environmental temperature and deterioration of the cable covering member due to ultraviolet irradiation.

Further, by using the existing hole as the trough fixing bolt insertion hole 41 for inserting the anchor bolt 43 for fixing the trough main body 3a to the concrete ground 35, a separate drilling process is not required. Further, even if the arrangement of the anchor nut 45 is slightly deviated, if the trough fixing bolt insertion hole 41 is a long hole, the alignment can be easily performed. Further, even when the arrangement of the anchor nut 45 is deviated from the existing hole, the trough fixing bolt insertion hole 41 can be easily formed at a position along the grooves 39a and 39b. At this time, the rib 37 can be used as a guide for forming the trough fixing bolt insertion hole 41.

Further, the trough body 3a and the trough lid 3b are both made of resin that hardly shields radio waves. Therefore, even if the leaky coaxial cable 5 is housed inside the closed space surrounded by the trough body 3a and the trough lid 3b, the leaky coaxial cable 5 inside the trough 3 and the antenna outside the trough 3 can be accommodated. Stable transmission and reception with little absorption of radio waves is possible.

Further, bolts 17 are used for fixing the trough main body 3a and the trough lid 3b, and anchor bolts 43 are used for fixing the trough main body 3a and the concrete ground 35. Therefore, an angle member or a band-shaped member is not used for fixing the trough body 3a and the trough lid 3b or fixing the trough body 3a to the concrete ground 35, so that the influence of electromagnetic waves by the fixing member is suppressed. be able to.

Further, the leaky coaxial cable 5 is arranged on the cable support member 11. Therefore, the leaky coaxial cable 5 can be supported at a predetermined height inside the trough main body 3a. Therefore, even when water enters the trough main body 3a, it is possible to prevent the leaky coaxial cable 5 from getting wet. Further, by arranging the concrete ground 35 at a predetermined distance, the influence of the reflection of radio waves on the concrete ground 35 can be suppressed. Further, since the top of the anchor bolt 43 and the lower part of the leaky coaxial cable 5 are arranged at a predetermined distance from each other, they do not interfere with each other. Compared with the case where the leaky coaxial cable 5 is placed directly on the concrete ground 35, the influence of reflection by the concrete ground 35 can be reduced, and further, due to the curl of the leaky coaxial cable 5, the leaky coaxial cable 5 becomes It can prevent meandering.

Further, in the cross section perpendicular to the longitudinal direction of the trough main body 3a, the leaky coaxial cable 5 can always be arranged at a constant angle inside the trough main body 3a by the cable support member 11. That is, the direction of the slot 23 of the leaky coaxial cable 5 can always be arranged in a fixed direction. Therefore, for example, good signals can be transmitted and received between the antenna provided on the train and the leaky coaxial cable 5.

Here, the leakage coaxial cable 5 can control the amount of radio wave leakage due to the design of the slot 23. In the present embodiment, as the distance from the feeding point (feeding portion 34) increases, the arrangement angle of the slot 23 of the leaky coaxial cable 5 becomes larger with respect to the cable axial direction, or the slot 23 becomes denser. Placed in. Therefore, by utilizing this characteristic, the relay interval can be increased by designing so that the arrangement angle and the arrangement density of the slots 23 increase as the distance from the feeding point increases. For example, the relay interval of the leaky coaxial cable 5 can be set to 1300 m to 1500 m, but the relay interval is not necessarily limited to the above range and can be set to 1000 m or less.

In the cable connection portion 31 of the leaky coaxial cable 5, for example, an amplifier or the like may be installed. By doing so, even when a plurality of leakage coaxial cables 5 are connected, stable and good transmission / reception of a signal is possible over the entire length.

[Second Embodiment]
Next, the second embodiment will be described. 14A is a perspective view of the cable support member 11a used in the second embodiment, and FIG. 14B is a front view. In the following description, the configurations that perform the same functions as those of the first embodiment are designated by the same reference numerals as those in FIGS. 1 to 13, and duplicated description will be omitted.

The cable support member 11a has almost the same structure as the cable support member 11, but the arrangement of the support portions 33 is different. In the cable support member 11 described above, the center line of the support portion 33 is arranged substantially at the center in the width direction of the cable support member 11 (on line H in FIG. 14B). On the other hand, the cable support member 11a is arranged at a position where the center line of the support portion 33 (line I in FIG. 14B) is deviated from the center in the width direction of the cable support member 11a.

FIG. 15 is an example of a plan conceptual diagram showing a leaky coaxial cable laying structure 1c in which a cable support member 11a is used (however, the trough lid 3b is not shown). As described above, in the trough structure 51 in which the plurality of troughs 3 are connected, the plurality of cable support members 11a are arranged at predetermined intervals in the longitudinal direction. The leaky coaxial cable 5 is arranged on the support portion 33 of each cable support member 11a.

Here, the cable support members 11a adjacent to each other in the longitudinal direction are formed in opposite directions to each other. That is, they are arranged so that the deviation direction of the support portion 33 of the cable support member 11a changes alternately with respect to the width direction of the trough main body 3a. In the illustrated example, the cable support members 11a are arranged in different directions so that the support portion 33 is displaced from the right direction → the left direction → the right direction in the drawing in order from the top in the drawing.

A leaky coaxial cable 5 is arranged on the support portion 33 of the cable support member 11a. Further, the support portions 33 of the cable support member 11a are arranged so as to alternate with each other in the longitudinal direction of the trough structure 51. Therefore, the leaky coaxial cable 5 is curved in a substantially S shape and loosely arranged so that continuous bent portions are alternately formed in the longitudinal direction of the trough structure 51. At this time, the leaky coaxial cable 5 is restrained by the cable support member 11a and bent toward the center of the trough 3 at each end of the cable support member 11a in the width (thickness) direction. That is, the leaky coaxial cable 5 is bent in a predetermined direction at both ends of the cable support member 11a in a state of being constrained by a distance corresponding to the width (thickness) of the cable support member 11a. Therefore, the stress generated in the leaky coaxial cable 5 is dispersed on both sides of the cable support member 11a, and the stress does not concentrate on one point of the leaky coaxial cable 5 arranged at the center of the cable support member 11a.

The amount of deviation of the support portion 33 from the center of the cable support member 11a can be evaluated, for example, by the amount at which the center of the substantially semicircular support portion 33 deviates from the center of the cable support member 11a. Define.

The offset amount of the support portion 33 of the cable support member 11a can be set according to the allowable bending angle of the leaky coaxial cable 5 used and the installation interval of the cable support member 11a. For example, when the outer conductor 25 of the leaky coaxial cable 5 is an aluminum pipe, the bending angle can be set to 4 °, but since it is repeatedly bent in an S shape, the bending angle is set to 2 in consideration of safety. It is desirable to keep it below °. When the outer conductor 25 is formed of a copper pipe, the S-shaped bending angle can be made larger than that of the case where the outer conductor is made of an aluminum pipe. However, in the present invention, the upper limit of the bending angle is matched with the bending angle of the aluminum pipe. Is 2 °.

Here, the cable support member 11a formed by offsetting the support portion 33 may be used, and the directions of the adjacent cable support members 11a separated by a predetermined distance may be reversed from each other and arranged in a staggered manner. By doing so, the support portions 33 can be offset in opposite directions with respect to the center line of the cable support member 11a. Therefore, the total offset amount of the support portions 33 of the adjacent cable support members 11a is twice the offset amount of the support portions 33 of the individual cable support members 11a.

For example, when the bending angle of the leaky coaxial cable 5 is 2 °, the deviation amount of the leaky coaxial cable 5 is about 3.5 cm per 1 m and about 7 cm per 2 m. Therefore, for example, when the cable support members 11a are arranged at intervals of 2 m, the formation position of the support portion 33 of the cable support member 11a may be offset by 3.5 cm from the center. In this way, for example, by arranging the cable support member 11a with an offset of 3.5 cm to the right and then arranging the cable support member 11a in the opposite direction, the support portion 33 is offset to the left by 3.5 cm. Can be placed.

When the bending angle of the leaky coaxial cable 5 is 0.5 °, the deviation amount of the leaky coaxial cable 5 is about 0.87 cm per 1 m and about 1.74 cm per 2 m. Here, if the bending angle is less than 0.5 °, the amount of deviation of the bent portion of the leaky coaxial cable is too small, and the effect of providing an extra length is insufficient. Therefore, the bending angle of the leaky coaxial cable 5 needs to be 0.5 ° or more and 2 ° or less, and it is desirable to set it to 1 ° or more and 2 ° or less.

By arranging the support portion 33 and the groove 33a of the cable support member 11a in different directions in the longitudinal direction, the leaky coaxial cable 5 is guided along the support portion 33a and has an S-shape in a plan view. It is arranged while meandering. For example, when the outer diameter of the leaky coaxial cable is about 51 mm, the length of the groove 33a of the support portion 33 of the support member is 60 mm in the longitudinal direction of the trough, but the length of the groove 33a may be appropriately determined. .. Here, the S-shaped mountain valley is restrained in a short straight line by the groove 33a of the support member 33, and is bent inward at both ends of the mountain valley, so that the S-shaped peak is bent near the center of the S-shape. A loose arrangement with points can be realized. With such a form, a margin is given to the length of the leaky coaxial cable 5 arranged in an S shape, so that the leaky coaxial cable 5 is stable even when a tensile force is applied to the leaky coaxial cable 5 due to shaking such as an earthquake. The laid state is maintained.

The cycle of the loose arrangement is 2 m to 6 m, which is the arrangement interval of the cable support member 11a. If the distance between the cable support members 11a exceeds 6 m, the effect of slack due to its own weight appears, the height of the leaky coaxial cable 5 becomes uneven, and the communication characteristics become unstable, which is not preferable. Further, when the distance between the cable support members 11a is less than 2 m, the leaky coaxial cable is stably bent at a small bending angle, and the S-shaped bending of the cable is locally stress-concentrated on the peaks and valleys. Becomes difficult to avoid. At the same time, an increase in the number of cable support members 11a installed causes an unnecessary increase in cost. Therefore, the arrangement interval of the cable support member 11a is preferably 2 m to 6 m. By setting the arrangement interval to 6 m or less in this way, the rigidity of the leaky coaxial cable itself does not affect the deflection due to its own weight.

In the leaky coaxial cable laying structure 1c, not only the cable support member 11a but also the cable support member 11 may be partially used. That is, in the leaky coaxial cable laying structure 1c, the cable support member 11a is used at least in part, and the support portion 33 of the cable support member 11a is formed at a position offset by a predetermined distance from the center in the width direction of the cable support member 11a. I just need to be there. By doing so, the leaky coaxial cable 5 can be loosely arranged on the cable support member 11a in a substantially S shape with respect to the longitudinal direction of the trough structure 51.

According to the second embodiment, the same effect as that of the first embodiment can be obtained. Further, by arranging the leaky coaxial cable 5 loosely in a substantially S shape with respect to the longitudinal direction of the trough structure 51, the leaky coaxial cable 5 can be arranged in a loosened state. Therefore, it is possible to relieve the stress when the leaky coaxial cable 5 receives tension from the outside in the event of an earthquake or the like as well as the change in the environmental temperature, and it is possible to prevent the leaky coaxial cable 5 from being deformed.

[Third Embodiment]
Next, a third embodiment will be described. FIG. 16A is a perspective view of the cable support member 11b used in the third embodiment. The cable support member 11b has substantially the same configuration as the cable support member 11, except that grooves 53 are formed on the side surfaces and the bottom surface along the circumferential direction of the cable support member 11b.

FIG. 16B is a front view showing a state in which the leaky coaxial cable 5 is arranged on the cable support member 11b. As described above, the leaky coaxial cable 5 is arranged on the support portion 33 of the cable support member 11b. Further, a string-shaped fixing member 55 is arranged in the groove 53. As the string-shaped fixing member 55, for example, a resin binding band is used.

The string-shaped fixing member 55 can fix the leaky coaxial cable 5 to the cable support member 11b. That is, at least a part of the leaky coaxial cable 5 mounted on the cable support member 11b is bound to the cable support member 11b by the string-shaped fixing member 55 and fixed to the cable support member 11b. Here, as the tightening force of the string-shaped fixing member, it is usually desirable to tighten the string-shaped fixing member with a tightening force within a range in which the cross-sectional deformation of the leaky coaxial cable does not occur. Further, when the leaky coaxial cable described later is not pressed by the pressing body, the tightening force of the string-shaped fixing member may be applied within the range where the cross-sectional deformation distortion rate of the leaky coaxial cable is 0.2%. In the leaky coaxial cable laying structure, the cable support member 11b may not be arranged at all positions, and the cable support member 11b may be arranged at least in a part and the cable support member 11 may be arranged in the rest. Further, in the cable support member 11b as well, the position of the support portion 33 may be offset in the width direction as in the cable support member 11a.

According to the third embodiment, the same effect as that of the first embodiment can be obtained. Further, by fixing the leaky coaxial cable 5 to the cable support member 11b with the string-shaped fixing member 55, the leaky coaxial cable 5 does not shift from the support portion 33 of the cable support member 11b in the event of an earthquake or the like. Further, by increasing the tightening force of the string-shaped fixing member 55 for fixing the leaky coaxial cable 5, the leaky coaxial cable 5 can be stably fixed.

[Fourth Embodiment]
Next, a fourth embodiment will be described. FIG. 17A is a front view showing a state before closing the trough lid 3b of the leaky coaxial cable laying structure 1d, and FIG. 17B is a front view showing a state in which the trough lid 3b of the leaky coaxial cable laying structure 1d is closed. .. In the leaky coaxial cable laying structure 1d, the pressing body 59a is arranged on the back surface of the trough lid 3b. The pressing body 59a is a resin foam, for example, made of a polyethylene foam sheet, and is configured by laminating a plurality of polyethylene foam sheets.

The pressing body 59a is arranged on the back surface of the trough lid 3b at a portion corresponding to the position where the cable support member 11 is arranged when the trough lid 3b is closed. Therefore, when the trough lid 3b is fixed to the trough body 3a with bolts 17, the pressing body 59a is arranged on the upper part of the leaky coaxial cable 5 on the cable support member 11.

In the leaky coaxial cable laying structure 1d, the pressing body 59a may not be arranged at all the parts where the cable support member 11 is arranged. That is, the pressing body 59a may be arranged on at least a part of the cable support member 11.

Further, the thickness of the pressing body 59a is thicker than the gap between the back surface of the trough lid 3b and the upper end of the leaky coaxial cable 5 when the trough lid 3b is closed. Therefore, when the trough lid 3b is fixed to the trough body 3a with the bolt 17, the pressing body 59a can be pressed by the trough lid 3b. Therefore, the leaky coaxial cable 5 placed on the cable support member 11 is pressed by the pressing body 59a (arrow J in FIG. 17B), and the leaky coaxial cable 5 can be fixed.

The pressing body 59a made of polyethylene foam sheet has an extremely large amount of deformation. Therefore, as shown in FIG. 17A, even if the pressing body 59a is substantially rectangular in front view, when the leaking coaxial cable 5 is pressed, the pressing body 59a is deformed along the outer shape of the leaking coaxial cable 5. Then, it adheres to the upper surface of the leaky coaxial cable 5. Therefore, the leaky coaxial cable 5 is sandwiched between the cable support member 11 and the pressing body 59b, and the leaky coaxial cable 5 can be efficiently fixed.

For example, a polyethylene foamed sheet (40-fold foamed product: a laminated body in which 6 sheets of 10 mm in thickness are laminated) is used as a pressing body 59a, and dimensions: a polyethylene foamed resin sheet having a predetermined thickness of 60 mm in thickness × 120 mm in length × 140 mm in width. When the top of the leaky coaxial cable having the largest pressing amount is pressed by 16%, the increase in the pulling force of the leaky coaxial cable 5 due to the increase in the pressing force by the pressing body 59a is 8.0 kg. Similarly, when a polyethylene foam sheet (40 times foamed product) is used as the pressing body 59a and pressed by 30%, the increase in the pulling force of the leaky coaxial cable 5 due to the increase in the pressing force by the pressing body 59a is 13. It is 0.0 kg. Therefore, when 50 pressing bodies 59a are arranged in a 100 m section at 2 m intervals, the increase in the pulling force of the leaky coaxial cable 5 is 400 kg and 650 kg, respectively. Here, for example, the cross-sectional deformation distortion rate corresponding to the diameter change of 51.01 mm to 50.93 mm before and after pressing the leaky coaxial cable when pressed by 30% is 0.16%, which is 0.20% or less. Becomes possible. That is, by providing polyethylene foam sheets having a foaming ratio of 40 times at predetermined intervals of 2 m, the pulling force per 100 m of the leaky coaxial cable can be set to 400 kg or more. Thereby, it is possible to secure a pulling force of 300 kg or more per 100 m by adjusting the pressing distance and the pressing amount.

The pressing body is not limited to the polyethylene foam sheet. FIG. 18A is a front view showing a state before closing the trough lid 3b of the leaky coaxial cable laying structure 1e, and FIG. 18B is a front view showing a state in which the trough lid 3b of the leaky coaxial cable laying structure 1e is closed. .. In the leaky coaxial cable laying structure 1e, the pressing body 59b is arranged on the back surface of the trough lid 3b. The pressing body 59b is a rubber molded body.

The pressing body 59b made of a rubber molded body has a smaller amount of deformation than the pressing body 59a made of a polyethylene foam sheet. Therefore, the pressing body 59b is formed with a notch 61 having a shape corresponding to the outer shape of the leaky coaxial cable 5 in advance. For example, as shown in the figure, a semicircular notch 61 is formed on the lower surface of the pressing body 59b.

The thickness of the pressing body 59b in the notch 61 is approximately equal to or slightly thicker than the gap between the back surface of the trough lid 3b and the upper end of the leaky coaxial cable 5 when the trough lid 3b is closed. Therefore, when the trough lid 3b is fixed to the trough body 3a with the bolt 17, when the pressing body 59b is pressed by the trough lid 3b, the leaky coaxial cable 5 mounted on the cable support member 11 is released by the pressing body 59b. It is pressed (arrow K in FIG. 18B). Therefore, the leaky coaxial cable 5 can be fixed. In this case, the leaky coaxial cable 5 is sandwiched and fixed between the support portion 33 of the cable support member 11 and the notch 61 of the pressing body 59b.

According to the fourth embodiment, the same effect as that of the first embodiment can be obtained. Further, since the leaky coaxial cable 5 is pressed by the pressing bodies 59a and 59b, a frictional force can be applied to the leaking coaxial cable 5 by contact between the leaking coaxial cable 5 and the pressing bodies 59a and 59b. Therefore, the resistance force against expansion and contraction in the axial direction with respect to the leaky coaxial cable 5 can be increased, and the pull-out resistance can be increased. As a result, it becomes difficult to pull out the leaky coaxial cable 5 from the inside of the trough main body 3a in one direction. Therefore, it is possible to prevent the leaky coaxial cable 5 from being stolen. Here, comparing both the pressing body 59a made of a laminated body of polyethylene foamed resin sheets and the pressing body 59b made of a rubber molded body, the former pressing body 59a, which is a foamed material of polyethylene which is a low dielectric constant material, is Further, since it is a material having a low dielectric constant, it can be used as a good pressing body with less disturbance of the electromagnetic field radiated from the leaky coaxial cable due to its low dielectric constant characteristics as compared with the latter rubber pressing body 59b.

[Communication characteristic confirmation test between concrete trough and resin trough]
As described above, the leaky coaxial cable is a cable for transmitting and receiving radio waves and performing wireless communication with a train. Therefore, if the cable is arranged in the trough for the purpose of protecting the cable, the trough may cause a loss of radio wave propagation and deteriorate the transmission / reception characteristics with the train. That is, by storing it in the trough, the coupling loss characteristic may be deteriorated. Further, since the leaky coaxial cable is an open transmission line, if there is a trough around it, the radio waves transmitted inside the leaky coaxial cable may be affected. That is, the transmission loss characteristic may deteriorate. Therefore, a confirmation test was conducted on the communication characteristics (bonding loss characteristics and transmission loss characteristics) of the resin trough structure. At this time, a comparison was also made in the case where the cable was simply placed on the cable support member on the concrete ground without using the resin trough structure.

(Communication characteristic confirmation test method)
The leaky coaxial cable was laid with a predetermined length by applying tension to the support wire, and the transmission loss and the coupling loss, which are the attenuation amounts of the leaky coaxial cable, were measured. For the measurement, the reference material in which the leaky coaxial cable was directly placed at a predetermined height on the cable support member directly arranged on the concrete ground surface was used as the test material A. On the other hand, the test material B is obtained by covering the trough body with a trough lid to form a closed space and placing a leaky coaxial cable on a support portion of a cable support member in the closed space in the trough at a predetermined height. , Test material C, and the communication characteristics of each test material were compared. The cable support members were arranged at intervals of 2 m, and a leaky coaxial cable was placed in a straight line with a length of about 10 m on a support portion having a predetermined height so that the slots faced in a predetermined direction. Here, the state in which the leaky coaxial cable is mounted on the trough structure at the time of the test will be described in detail. The internal dimensions of the trough body in the trough structure used in the test were width 170 mm × height 145 mm × length about 1000 mm, and a support member was arranged inside the trough structure. The dimensions of the support member are width 150 mm × height 80 mm × length 60 mm (trough longitudinal direction), and have a semicircular (27R) support portion in the center in the width direction. A groove for accommodating the support wire is formed at the lowermost end of the support portion. A leaky coaxial cable is placed on the support portion, and a trough lid is covered on the upper portion of the side wall portion of the trough body. At this time, a space having a height of about 40 mm can be secured between the upper part of the leaky coaxial cable and the trough lid.

Here, a resin sheet is used so that the height at which the cable support members of the test material A, the test material B, and the test material C are arranged is constant according to the bottom thickness of the trough body of the test material C. It was adjusted to 50 mm. Here, a polyolefin-based recycled resin trough, which will be described later, was used as the test material B, and a concrete trough was used as the test material C. The resin trough used for the test material B and the concrete used for the test material C were used. The trough used was of the same size standard. As the polyolefin-based recycled resin used for the test material B, a material containing 36% by mass of the total mass of the recycled resin in total containing inorganic substances was used. The mass ratio of each inorganic substance of the test material B to the entire resin material is 19% by mass of magnesium hydroxide, 15% by mass of calcium carbonate, and 2% by mass of titanium oxide in consideration of strength, flame retardancy, weather resistance, and the like. %.

Further, in all the test materials, the same cable support member having a groove for inserting the support wire formed perpendicular to the bottom surface of the cable support member was used. That is, the slot of the leaky coaxial cable was arranged at a height of about 40 mm from the bottom surface of the cable support member so as to face vertically upward with respect to the concrete ground. Therefore, the support height of the leaky coaxial cable from the concrete ground is the same for all the test materials.

Here, a polyolefin-based recycled resin trough body and a trough lid were used as the test material B, and a concrete trough body and a trough lid were used as the test material C. The communication characteristics of these test materials A, test material B, and test material C were evaluated. In addition, the case where the surface of the trough body and the trough lid of the test material B and the test material C were each wet with water was also evaluated. In this case, in order to allow the trough body and the trough lid to absorb water, the trough body and the trough lid were immersed in the water of the tray for 24 hours, and then the trough taken out from the tray was tilted several times to remove the adhering water on the surface. The test materials corresponding to these test materials B and C were used as test materials D and E, and the communication characteristics of the test materials D and E were also evaluated. At this time, the support height of the leaky coaxial cable in the case of the test material D and the test material E was set to be the same as in the case of the test material B and the test material C.

Specifically, the measurement of the bond loss characteristic is performed by the following method. A CW (Continuous wave) signal is input from one end (one end) of the leaky coaxial cable at a predetermined frequency using a transmitter or the like, and the CW signal is transmitted inside the leaky coaxial cable. At this time, a non-reflective terminating resistor is connected to the other end (opposite end). Then, the strength of the CW signal of the radio wave radiated from the leaky coaxial cable is received by a receiver such as a spectrum analyzer by a half-wave dipole antenna installed at a height of 1.5 m directly above the leaky coaxial cable. .. At this time, the half-wave dipole antenna was moved at a predetermined speed along the laying length of the leaky coaxial cable of 10 m for measurement. The value obtained by averaging the decibel difference between the strength of the CW signal transmitted inside the leaky coaxial cable and the strength of the CW signal received by the half-wave dipole antenna immediately above it in the longitudinal direction of the cable was taken as the coupling loss.

On the other hand, the measurement of the transmission loss characteristic is specifically carried out by the following method. A CW signal in a predetermined frequency range is input from one end (one end) of the leaky coaxial cable using a network analyzer or a spectrum analyzer with a tracking generator. Then, the CW signal output from the other end (the other end) is received by using the same measuring instrument. The decibel difference in the strength of these two signals was taken as the transmission loss.

Table 1 shows the communication characteristic evaluation test results of the leaky coaxial cable of various test materials. At this time, the transmission loss was taken as an average value with respect to the frequency of the measurement result in 400 to 440 MHz. Further, assuming that the actual section length of the leaky coaxial cable is about 1.5 km, the display unit is a value converted to dB / km.

(Communication characteristic evaluation result)
The transmission loss of the test material B using the resin trough and the reference test material A in the 400 MHz to 440 MHz band was almost the same, about 22 dB / km. On the other hand, the test material C using the concrete trough was 27 dB / km, and the test material C using the concrete trough was inferior to the test material B using the resin trough. Further, the coupling loss of the reference test material A in the 400 MHz and 440 MHz bands is 63 dB, whereas the coupling loss of the test material B is 62 dB at 400 MHz and 63 dB at 440 MHz, both of which are almost the same. It was. On the other hand, the bond loss of the test material C using the concrete trough increased by 3 dB at 400 MHz and 5 dB at 440 MHz as compared with the reference test material A. Here, in the case of the concrete trough, not only the bond loss (average value) is large, but also the variation is large.

As described above, the communication characteristics when the resin trough structure is used are that the transmission loss is within ± 1 dB / km and the coupling loss is within ± 1 dB as compared with the case where the resin trough is not used (reference). Met. That is, even if a resin trough structure is used, the transmission loss and the coupling loss are at least within ± 2 dB / km and within ± 2 dB as compared with the case where the resin trough is not used (reference). It was confirmed that the characteristics were satisfied.

Further, the outer surface and inner surface of the resin trough are wetted with water and absorbed as test material D, and the outer and inner surfaces of the concrete trough are wetted with water and absorbed with water as test material E. A confirmation test was conducted. As a result, in the test material D using the resin trough, even if the outer surface and inner surface of the trough are wetted with water to absorb water, the outer surface and inner surface of the trough hardly absorb water, so that both transmission loss and coupling loss are external. It is almost the same as when the surface and inner surface are dry. On the other hand, in the case of the test material E in which the outer and inner surfaces of the concrete trough are wetted with water to absorb water, the transmission loss increases by 3 dB / km and the coupling loss increases by about 1 dB due to the water absorption of the concrete. Both loss and bond loss tended to increase.

Based on the above, a resin cable support member is placed inside a closed space formed by a trough body made of resin and a trough structure using a trough lid, and a leaky coaxial cable is placed on it at a predetermined height and a predetermined angle. The communication characteristics in the predetermined conditions of the 400 to 440 MHz band when placed are the reference (the leaky coaxial cable is placed on the cable support member arranged by adjusting the height with a resin sheet on the concrete ground without the presence of the trough structure. It was confirmed that the communication characteristics were such that the change in transmission loss was within ± 1 dB / km and the change in coupling loss was within ± 1 dB, as compared with (when mounted at a predetermined height and a predetermined angle). That is, at least, it is possible to obtain communication characteristics in which the transmission loss and the coupling loss are within ± 2 dB / km and within ± 2 dB, respectively.
Considering the effect of rainwater, if there is a lot of water and rainwater in the vicinity of the leaky coaxial cable, the water itself has a large electromagnetic wave absorption characteristic, so the transmission loss characteristic and coupling loss characteristic of the leaky coaxial cable deteriorate significantly. However, when the leaky coaxial cable is housed in a trough with a support member and the separation from the upper surface of the leaky coaxial cable to the trough structure can be secured to a certain extent, for example, when about 40 mm can be secured, it is close to the submerged condition. Since the presence of water in the vicinity of the leaky coaxial cable can be avoided even under the conditions, it is considered possible to suppress deterioration of the transmission loss characteristic and the coupling loss characteristic.

Similarly, as a result of the communication characteristic confirmation test in the 400 to 440 MHz band of the trough structure, even when the outer surface and the inner surface of the trough structure are wetted with water to absorb water, the outer surface and the inner surface of the trough structure are also absorbed. Communication characteristics equivalent to those when the surface was dry were obtained. Furthermore, even when compared with the reference, it can be confirmed that the change in transmission loss is within ± 1 dB / km and the change in coupling loss is within ± 1 dB. It is possible to obtain communication characteristics in which the changes are within ± 2 dB / km and within ± 2 dB, respectively. On the other hand, it can be seen that the concrete trough is further inferior to the resin trough in the communication characteristics when it is wetted with water and absorbed.

(Water absorption rate of test material)
The test material B is a polyolefin-based recycled resin containing 36% by mass of the total mass of the recycled resin in total, and the water absorption rate after water absorption at 23 ° C. for 24 hours was measured based on JIS K7209 equivalent to ASTM D570. The rate was 0.13%, satisfying 0.15% or less. The water absorption rate of the polyolefin resin containing no recycled material or inorganic substances is 0.025%, which satisfies 0.03% or less. The water absorption rate of concrete based on JIS A 1110 varies depending on the type of aggregate used for concrete and the ratio of water to cement at the time of casting, but the water absorption rate after the 24-hour water absorption test is at least 2. % Or more. Therefore, it is known that the water absorption rate of concrete is one digit or more higher than that of the polyolefin-based recycled resin. It is considered that this is the cause of the decrease in the transmission loss and the coupling loss of the concrete trough due to water absorption even though the transmission loss and the coupling loss do not increase even if the trough made of recycled resin containing a predetermined amount of inorganic substances is used.

(Corrosion resistance confirmation test of test material)
Further, in a test in which the polyolefin-based recycled resin made of the test material B was immersed for 24 hours at room temperature in accordance with JIS K7114, the following corrosion resistance confirmation test was performed to determine the mass change rate of each.
(1) Immersion test of 3% NaCl aqueous solution which is a seawater simulated solution.
(2) 30% CaCl ₂ immersion test as a simulated snow melting agent.
(3) Immersion test with a test solution obtained by diluting a liquid obtained by mixing _{H 2} SO ₄ and _{H NO 3} as an acid rain simulated solution at a ratio of 2: 1 to a concentration of 1%.
In each test, three test pieces were prepared and tested, and the average value of the three pieces was calculated. The test results are shown in Table 2.

As a result, in any of the above tests, it was confirmed that the mass change rate of the mass of the test piece after the test with respect to the mass of the test piece before the test was 0.1% or less. In this way, the trough made of recycled resin for communication by the leaky coaxial cable of the present application satisfied all of the environmental tests of the seawater simulated liquid, the snow melting agent simulated liquid, and the acid rain simulated liquid, so that it can be used in a harsh external environment. Can follow.

Further, regarding the polyolefin-based recycled resin made of the test material B, a weather resistance confirmation test was conducted in addition to the corrosion resistance. For this test, a weather resistance acceleration tester (eye super UV tester: model number SUV-W161) manufactured by Iwasaki Electric Co., Ltd. was used. Eight levels of 250 hours, 250 hours, 250 hours, 500 hours, 750 hours, 1000 hours, 1250 hours, 1500 hours, 1750 hours, and 2000 hours are specified for the polyolefin-based recycled resin at intervals of 250 hours. The tensile strength and the Charpy impact value of each test piece were determined by irradiating with ultraviolet light for a certain period of time and under predetermined conditions.

Here, as the light source of the weather resistance acceleration tester, a metal halide lamp for the weather resistance tester manufactured by Iwasaki Electric Co., Ltd., which irradiates ultraviolet rays having a wavelength of 295 nm or more, was used. As the conditions for ultraviolet light irradiation, the irradiation intensity of ultraviolet light was set to 90 mW / cm ^2, and ultraviolet light was irradiated in an environment of 50% humidity without spray spraying assuming rain. In addition, each test piece and test was tested according to JIS K7161 and JIS K7162. Here, the surface of the tensile test piece was used as the irradiation surface, and the Charpy impact test piece was irradiated with ultraviolet light from a direction perpendicular to the notch forming surface, that is, from the normal direction of the notch forming surface. The test results are shown in Table 3.

As shown in Table 3, the residual ratio of the tensile strength of the test piece after irradiation with ultraviolet light for 2000 hours is 95% or more, and the residual ratio of the Charpy impact value with respect to the tensile strength and Charpy impact value of the test piece before irradiation with ultraviolet light. The rate was 90% or more, and it was confirmed that the product had sufficient strength and impact characteristics without a sudden decrease in strength.

Although the description is omitted in Table 1, in addition to the polyolefin-based recycled resin material used in the above-mentioned communication characteristic evaluation, a trough made of high-density polyethylene resin using a virgin material which is a polyolefin resin is used in the same manner. Communication characteristic evaluation test was conducted. Even when the trough body made of high-density polyethylene resin and the trough lid are used, the transmission loss is within ± 1 dB / km and the bond loss is within ± 1 dB with respect to the reference material as in the case of the test material B and the test material D. It was confirmed that it had a range of communication characteristics. That is, it was found that it is possible to obtain communication characteristics in which the transmission loss and the coupling loss are within ± 2 dB / km and within ± 2 dB, respectively.

For cost reduction, it is desirable that the polyolefin resin forming the trough is a polyolefin-based recycled resin having a predetermined strength and having high corrosion resistance and high weather resistance. At this time, an inorganic substance such as calcium carbonate, magnesium hydroxide or titanium oxide may be added in an amount of 40% by mass or less of the total mass of the recycled resin within a range that does not affect the communication characteristics. It is desirable that it is 34% by mass or more and 36% by mass or less. By containing about 36% by mass of an inorganic substance in the recycled resin, it is possible to obtain a flame-retardant polyolefin resin having excellent weather resistance. Therefore, even if an inorganic substance is added within the range of 36% by mass or more and 40% by mass of the total mass of the polyolefin-based recycled resin, the strength and telecommunications characteristics that are not practically problematic can be maintained. Further, it was confirmed that the polyolefin-based recycled resin has excellent telecommunications characteristics and has no problem in corrosion resistance. Of course, if a polyolefin-based recycled resin is used, it has almost the same strength as the polyolefin resin and can reduce the cost. As the resin trough, a general-purpose resin having a predetermined strength can be used instead of the recycled resin. In this case, a virgin resin of a polyolefin resin having excellent dielectric properties and water resistance is suitable instead of the polyolefin-based recycled resin. ing.

The polyolefin-based recycled resin material containing an inorganic substance preferably contains at least magnesium hydroxide and titanium oxide as the inorganic substance and has a dielectric constant of 3.15 or less. In this case, it is desirable that the content of magnesium hydroxide is 18% by mass or more with respect to the total mass of the polyolefin-based recycled resin material. More preferably, the inorganic substances are magnesium hydroxide, calcium carbonate, and titanium oxide, and the content ratio of each of the polyolefin-based recycled resin materials to the total mass is 18 to 21.3% by mass of magnesium hydroxide and 14 by mass of calcium carbonate. It is contained in the range of ~ 16.5% by mass and 2 to 2.2% by mass of titanium oxide, and the total content of inorganic substances is 34% by mass or more and 40% by mass or less with respect to the total mass of the polyolefin-based recycled resin material. Is desirable. By doing so, a polyolefin-based recycled resin material having excellent flame retardancy and communication characteristics can be obtained.

For example, such a polyolefin-based recycled resin material is effective as a material for a structure or member for telecommunications. For example, by using it for the trough structure described above, it is possible to obtain a communication method or communication system having excellent communication characteristics.

(Dielectric constant measurement test of the material forming the trough body)
<Measurement method of permittivity>
The optimum measurement method for the dielectric constant measurement differs depending on the measurement frequency band, but in the 400 MHz frequency band as in the present invention, the measurement by the capacitance method is suitable. Further, the dielectric constant of a material in which a plurality of inorganic substances are dispersed in a resin as in the present invention becomes larger than that in the case of only the base resin due to the inclusion of the inorganic substances in the resin, and is further affected by the dispersed state of the inorganic substances. Therefore, it cannot be predicted without actual measurement.

In the present invention, the dielectric constant of the poolefin-based recycled resin forming the trough structure was measured. For the dielectric constant measurement, a test piece having a width of 15 mm, a length of 15 mm, and a thickness of 2 mm obtained by kneading the resin and the inorganic substance and then processing them with a roll was used. By the capacitance method, a wide band frequency band of 100 MHz to 600 MHz is scanned as a frequency band, and the dielectric constant of the test piece in the frequency band of 400 to 440 MHz is measured, and then the dielectric constant at 400 MHz, 420 MHz, 440 MHz is measured. The rate was obtained and used as the measured value.

For the measurement, an E4991B impedance annerizer manufactured by KEYSIGHT TECHNOLOGIES was used. As the fixing jig for measuring the test piece, the company's E16453A was used, and the measurement was repeated 5 times, and the average value was taken as the dielectric constant in each frequency band.

<Material forming the trough body used for dielectric constant measurement>
The following three types of materials, test material B, test material B1, and test material B2, were prepared as materials for forming the trough body, and the dielectric constant was measured. For the measurement of the dielectric constant, in addition to the test material B, a composition B1 in consideration of the variation in the resin composition and a composition B2 in consideration of the variation in the inorganic substance were prototyped to obtain the dielectric constant.

Here, the content of the inorganic substance in the test material B is the target composition of the recycled resin. Further, in the test material B1, polypropylene is increased in the resin composition constituting the base resin. Specifically, the test material B has a composition ratio of polyethylene: polyppyrene = 9: 1, whereas the test material B1 has a composition corresponding to polyethylene: polyppyrene = 8: 2, which is twice as much polypropylene. It is a material.

The test material B2 assumes a case where the content of the inorganic substance is about 10% higher than the target standard composition of the inorganic substance due to some reason. The contents of the inorganic substances of magnesium hydroxide, calcium carbonate, and titanium oxide in the test material B are 20.9% by mass, 16.5% by mass, and 2.2% by mass, respectively, for a total of 39.6% by mass. However, the test material B2 is a material in which magnesium hydroxide is 21.3% by mass, calcium carbonate is 16.5% by mass, and titanium oxide is 2.2% by mass in order to cut the total composition of the inorganic substances to 40% by mass. ..

Since each inorganic substance is added by compounding calculation, the content of the normally contained inorganic substances does not increase by 10% at the same time, and actually falls within a variation range of at most several%. It is considered to be. Therefore, it is considered that if the dielectric constant of the test material B2 is suppressed, it is sufficient to grasp the variation when the content of the inorganic substance is large. Further, in the present invention, conversely, when the content of the inorganic substance is slightly smaller than the target standard composition, the contents of the inorganic substances of magnesium hydroxide, calcium carbonate and titanium oxide are 18% by mass and 14 by mass, respectively. Since it is permissible to contain a total of 34% by mass in the mass% and 2% by mass, the test material corresponding to this composition is used as the test material B3, and the dielectric constant of the test material B3 is measured in addition to the test materials B1 and B2. went.

<Permittivity measurement results of the material forming the trough body>
Table 4 shows the dielectric constant measurement results of each test material as the dielectric constant measurement results of the materials forming the trough body. The measurement result of the dielectric constant of the test material B was constant at 3.04 at any frequency in the frequency band of 400 to 440 MHz. The dielectric constant of the test material B1 having a large amount of polypropylene in the resin composition was 3.06 at frequencies of 400 and 420 MHz and 3.07 at frequencies of 440 MHz. Further, the dielectric constant of the test material B2 in which the content of each inorganic substance is increased by about 10% is 3.14 at frequencies of 400 and 420 MHz and 3.15 at 440 MHz, and the dielectric constant of the test material B2 is higher than that of the test material B. The dielectric constant increased by about 0.10 to 0.11.

On the other hand, the permittivity of the test material B3 having a low content of inorganic substances is 3.00 at frequencies of 400 MHz and 420 MHz, and 3.01 at frequencies of 440 MHz, which is the permittivity of test material B3. The result was that the dielectric constant was slightly lower than the dielectric constant of the test material B. From the above results, it is considered that the influence of the material contained in the resin on the dielectric constant is larger for the inorganic substance than for the influence of the fluctuation of the resin component, but even in the case of B2 having the maximum content of the inorganic substance. Compared with the test material B having the standard composition, the increase in the dielectric constant is not so large and the influence is small. Incidentally, as described above, the dielectric constant of polyethylene in this frequency band is 2.35, and the dielectric constant of polypropylene is 2.65.

<Comparison of permittivity with concrete trough>
Comparing the permittivity of the test materials B to B3 in Table 4 with the permittivity of the concrete, the permittivity of the test material B is 3.04 in the entire measurement frequency band of 400 MHz to 440 MHz, and the inorganic substance content is high. Even with a high dielectric constant of the test material B2, it is at most 3.15. On the other hand, the dielectric constant of concrete is usually 6.0, which is much higher than that of the resin used for the above test material. Therefore, in the test results shown in Table 1, it is considered that the communication characteristics of the concrete trough were inferior to those of the resin trough of the present invention.

<Telecommunication test results of test materials B1, B2, B3>
Here, for confirmation, the telecommunications characteristics of the test materials B1, B2, and B3 were evaluated at three frequencies of 400 MHz, 420 MHz, and 440 MHz under the same conditions as in Table 1. As a result, the transmission loss and the coupling loss of the test material B1 were 22 dB at any frequency, the coupling loss was 62 dB at 400 MHz and 420 MHz, and 63 dB at 440 MHz, which were the same as those of the test material B.

On the other hand, the test material B3 having a low content of inorganic substances had a transmission loss of 22 dB and a coupling loss of 62 MHz at any frequency of 400 to 440 MHz. Even in the case of the test material B2 having a large inorganic content, the transmission loss was 22 dB, but the coupling loss was 63 dB at any frequency of 400 MHz, 420 MHz, and 440 MHz, and the result was obtained that the coupling loss increased by about 1 dB. ..

It was found that the above measurement results of the test material B1, the test material B2, and the test material B3 show the same results as the reference material in Table 1. That is, when the resin troughs of the test material B1, the test material B2, and the test material B3 are used, the transmission loss is compared with the case of the reference in which the leaky coaxial cable is exposed and arranged without using the resin trough. It was confirmed that the coupling loss satisfies the communication characteristics in the range of at least ± 2 dB / km and within ± 2 dB. Here, the reason why the exposed coaxial cable showed the same telecommunications characteristics as when it was placed on the support member inside the resin trough structure is due to the influence of the reflected wave from the concrete ground. Is thought to be because it is larger.

Further, in considering the loss of electromagnetic waves in the resin trough and the concrete trough, more strictly speaking, it is necessary to consider the influence of the thickness of each material in addition to the dielectric constant. Therefore, the relationship between the thickness of the resin trough and the concrete trough used in the confirmation test of the communication characteristics of the present invention was investigated. In the case of the resin trough, the lid thickness of the trough lid is 10 mm, the wall thickness of the trough body is 7 mm, and the maximum wall thickness of the trough body is 10 mm, whereas in the case of a concrete trough, the lid thickness of the trough lid is 10 mm. The thickness was 30 mm, the wall thickness of the trough body was 50 mm, and the maximum thickness of the trough body was 50 mm. The wall thickness of the concrete trough is thicker than that of the resin trough because the concrete trough absorbs electromagnetic waves and cannot be arranged with reinforcing bars, so that the wall thickness needs to be increased.

As described above, in the case of the resin trough, not only the dielectric constant is lower than that of the concrete trough, but also the maximum shielding of the outer circumference of the trough structure including the trough lid and the trough body shielded by the trough. The thickness is 10 mm or less, which is thinner than the shielding thickness in the case of concrete trough. As described above, not only the dielectric constant but also the influence of the maximum shielding thickness of the trough structure is superimposed on the telecommunications characteristics. As a result, in the above-mentioned telecommunications test, the polyolefin resin trough containing the inorganic substances of the test material B, the test material B1, the test material B2, and the test material B3 has better communication characteristics than the concrete trough. became.

<Tensile test and bending test of trough-forming material>
In the tensile test of the material forming the trough, the test materials B, B1, B2, and B3 are processed into a sheet by injection molding, and then processed into a JIS No. 2 test piece according to JIS-K7113 and the tensile speed. It was performed at 50 mm / min. In the bending test, the flexural modulus of the test pieces of the test materials B, B1, B2, and B3 was measured at a sample thickness of 4 mm and a bending speed of 2 mm / min in accordance with JIS K7171. Specifically, a test piece (thickness 4 mm, width 10 mm, length 80 mm) is prepared by injection molding, and a load is applied at a distance between fulcrums of 64 mm, a radius of curvature of the fulcrum and the point of action of 5 mm, and a test speed of 2 mm / min. A bending test was performed to measure the flexural modulus. Here, the tensile test and the bending test were performed 5 times each, and the average values were obtained as the tensile strength and the flexural modulus.

Here, the flexural modulus Ef is
Distortion 0.0005 (.epsilon.f ₁₎ Flexural was measured in deflection of the stress .sigma.f ₁
Distortion 0.0025 (.epsilon.f ₂₎ was measured in the amount of deflection in the bending stress .sigma.f ₂
And divide these differences by the difference in the corresponding amount of strain,
That is, the following equation Ef = (σf _2- σf ₁ ) / (εf _{2- εf 1} )
Can be obtained at. The results are shown in Table 5.

As a material for a trough structure for a leaky coaxial cable, it is considered that it can be used if the tensile strength is 20 MPa or more and the flexural modulus is 1000 MPa or more. From the results of the tensile test and the bending test shown in Table 5, any of the test materials B, B1, B2, and B3 satisfies these values.

Here, as the trough material, if the trough structure satisfies a predetermined telecommunication property and has the necessary mechanical property as the trough structure, it can be put into practical use. Therefore, if a material having a dielectric constant of 3.15 or less, a tensile strength of 20 MPa or more, and a flexural modulus of 1000 MPa or more is used as a trough material for accommodating the leaky coaxial cable, telecommunications of the leaky coaxial cable is used. It can be used as a material for trough structures for leaky coaxial cables without impairing its properties. Therefore, all of the test materials B, B1, B2, and B3 can be used as materials for the trough body and the trough lid that form the trough structure for the leaky coaxial cable.

<Charpy impact test of material forming trough>
Since the cable storage structure may be hit by a tool due to a mistake during track maintenance work or the like, a predetermined impact strength is required as a material for the trough structure that houses the leaky coaxial cable. For example, it is expected to have a mechanical property of 5 kJ / m ^{2 or more as a Charpy impact strength.} Therefore, the test materials B, B1, B2, and B3 were subjected to a Charpy impact test at 23 ° C. using a notched test piece based on JIS K7111. The test was repeated 5 times, and the average value was taken as the Charpy impact value. The results of the Charpy impact test shown in Table 5 all ^{satisfied the above 5 kJ / m 2} or more. As a result, it was confirmed that the polyolefin resin material containing the inorganic substance of the present invention has practically no problem in both telecommunications characteristics and impact characteristics.

As described above, the resin containing an inorganic substance, which constitutes the trough in the laying structure of the leaky coaxial cable, is a polyolefin-based resin having a dielectric constant of 3.15 or less in the above-mentioned frequency 400 to 440 MHz band measured by the capacitance method. If it is a recycled resin, it is possible to obtain a communication method using a laying structure of a leaky coaxial cable having excellent communication characteristics. By applying a material having a predetermined dielectric constant to the trough structure in the laying structure of the leaky coaxial cable in this way, the leaky coaxial cable mounted inside the trough structure and the on-vehicle antenna of the train can be combined. It is possible to realize a communication method for communicating with each other in a frequency band of 400 MHz band. At this time, it is desirable that the wall thickness of the trough structure in which the leaky coaxial cable is housed is thin, and for example, the maximum wall thickness is preferably 10 mm or less.

Further, if the resin containing an inorganic substance constituting the trough in the laying structure of the leaky coaxial cable is a polyolefin resin containing an inorganic substance having a dielectric constant of 3.15 or less in the 400 to 440 MHz frequency band measured by the capacitance method. , A communication system using a leaky coaxial cable laying structure having excellent communication characteristics can be obtained. By applying a material having a predetermined dielectric constant to the trough structure in the laying structure of the leaky coaxial cable in this way, the leaky coaxial cable mounted inside the trough structure and the on-vehicle antenna of the train can be combined. It is possible to realize a communication system that communicates with each other in a frequency band of 400 MHz. Even in this case, as the trough structure formed of the polyolefin resin containing an inorganic substance, it is desirable that the wall thickness of the trough structure in which the leaky coaxial cable is housed is thin, and for example, the maximum wall thickness is preferably 10 mm or less. ..

Further, as the polyolefin-based recycled resin material containing the inorganic substance, it is possible to provide a trough body that not only satisfies the dielectric constant of 3.15 or less, but also satisfies the tensile strength of 20 MPa or more and the bending elastic modulus of 1000 MPa or more. become. Further, it is possible to obtain a molded body of a trough body having ^{a Charpy impact strength of 5 kJ / m 2} or more as an impact characteristic as well as a flexural modulus as a tensile strength and a bending characteristic.

<Water absorption rate, corrosion resistance, weather resistance test for test materials B1, B2, B3>
Similar to the measurement of the water absorption rate after water absorption at 23 ° C. for 24 hours, the test material B1, the test material B2, and the test material B3 were additionally subjected to the same test. As a result, all of the materials forming the trough body satisfied the water absorption rate after water absorption at 23 ° C. for 24 hours based on JIS K7209 equivalent to ASTM D570 of 0.15% or less. Therefore, the trough body can be formed by using any of the test materials.

Further, similarly to the test on the test material B shown in Table 2, the same corrosion resistance test was additionally performed on the test material B1, the test material B2, and the test material B3. As a result, the materials forming the trough body were all based on JIS K7114, and in a test in which they were immersed for 24 hours at room temperature, a immersion test of a 3% NaCl aqueous solution, which is a seawater simulated solution, and a snow melting agent simulated solution were used. 30% CaCl ₂ immersion test and seawater simulation solution test with a test solution diluted to a concentration of 1% with a mixture _{of H 2} SO ₄ and HNO ₃ as an acidic rain simulation solution at a ratio of 2: 1. The results obtained that the mass change rate in the snow melting agent simulated liquid test and the acidic rain simulated liquid test satisfied 0.10% or less. Therefore, the trough body can be made of any material of polyolefin resin.

Further, similarly to the test on the test material B shown in Table 3, the same test was additionally performed on the test material B1, the test material B2, and the test material B3. As a result, the material forming the trough body is the tensile strength of the polyolefin-based recycled resin after the weather resistance promotion test in which ultraviolet light having an irradiation intensity of ^{90 mW / cm 2 is irradiated for 2000 hours in an environment of 50% humidity.} It was confirmed that the residual ratio of the Charpy impact value was 95% or more of the tensile strength before the irradiation with ultraviolet light, and the residual ratio of the Charpy impact value satisfied 90% or more of the Charpy impact value before the irradiation with the ultraviolet light. Therefore, the trough body can be formed by using any polyolefin resin material.

<Communication method with the on-vehicle antenna using the laying structure of the leaky coaxial cable>
As described above, by forming the resin material constituting the trough structure in the laying structure of the leaky coaxial cable with a polyolefin-based recycled resin containing an inorganic substance having a dielectric constant of 3.15 or less in the frequency 400 to 440 MHz band, the trough is formed. Obtain a communication method using a leaky coaxial cable laying structure capable of good communication in the frequency 400 MHz band between the leaky coaxial cable mounted inside the structure and the on-vehicle antenna of the train. be able to. At this time, it is desirable that the maximum wall thickness of the trough structure is 10 mm or less. By setting the wall thickness of the trough structure to 10 mm or less, a good communication state can be obtained.

In addition, the transmission loss is within ± 2 dB / km compared to the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on a cable support member whose height is adjusted on the concrete ground without using a trough structure. It is possible to obtain a communication method using a leaky coaxial cable laying structure, which has communication characteristics in a range of ± 2 dB or less in coupling loss.

<Communication system with on-vehicle antenna using leaky coaxial cable laying structure>
Further, if the resin material constituting the trough structure in the laying structure of the leaky coaxial cable is a polyolefin-based recycled resin containing an inorganic substance having a dielectric constant of 3.15 or less in the frequency 400 to 440 MHz band, the inside of the trough structure It is possible to obtain a communication system using a leaky coaxial cable laying structure that communicates between the mounted leaky coaxial cable and the on-vehicle antenna of the train in a frequency band of 400 MHz.

In addition, the transmission loss is within ± 2 dB / km compared to the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on a cable support member whose height is adjusted on the concrete ground without using a trough structure. It is possible to obtain a communication system using a leaky coaxial cable laying structure having communication characteristics in a coupling loss range of ± 2 dB or less.

To summarize the above features of the present invention, the leaky coaxial cable 5 is placed on the cable support members 11, 11a, 11b in a closed space formed of a resin trough without exposing the leaky coaxial cable 5 to the external environment. Even when arranged, good communication characteristics were obtained without deterioration of transmission characteristics due to the absorption of radio waves from the resin trough. Therefore, the leakage coaxial cable 5 due to the wind pressure when the train passes is prevented from being damaged by the local bending fatigue, and the durability is improved. Further, since the leaky coaxial cable 5 is not deteriorated by ultraviolet irradiation, a leaky coaxial cable laying structure capable of dramatically extending the life of the leaky coaxial cable 5 can be obtained.

Further, in the present invention, since the leaky coaxial cable 5 is placed on the support portion 33 of the cable support members 11, 11a, 11b inside the trough 3, the leaky coaxial cable 5 vibrates or leaks due to the wind pressure of the train. The surface of the coaxial cable 5 will not get wet with rainwater or the like. Therefore, the communication characteristics of the radio wave transmitted from the leaky coaxial cable 5 are stable, and good communication characteristics can be obtained. Further, if the trough 3 is made of resin, unlike concrete, the trough 3 hardly absorbs rainwater even if the surface of the trough 3 gets wet with rain, so that the communication characteristics are stable. Moreover, since the resin trough is lightweight unlike concrete, it has excellent installation workability. Further, since the leaky coaxial cable 5 is not exposed to the external environment, the influence of the temperature change in the external environment can be mitigated. Further, since the leaky coaxial cable 5 is mounted on the cable support members 11, 11a, 11b, the influence of radio waves from the concrete ground can be mitigated.

Further, the leaky coaxial cable 5 can be loosely arranged by being curved in a substantially S shape so that continuous bent portions are alternately formed in the longitudinal direction on the cable support member 11a in the trough 3. .. By doing so, even if tension is applied to the leaky coaxial cable 5 in the event of an external environmental temperature change or an earthquake, it is possible to prevent breakage of the outer conductor of the leaky coaxial cable 5 due to the tension. ..

Further, at least a part of the leaky coaxial cable 5 is bound to the cable support member 11b by the string-shaped fixing member 55 and fixed to the cable support member 11b, so that the leaky coaxial cable 5 can be reliably supported. .. Further, in at least some of the cable support members 11, 11a, 11b, a pressing body made of either a polyethylene foam sheet or a rubber molded body is placed on the upper portion of the leaky coaxial cable 5 mounted on the cable support members 11, 11a, 11b. By arranging the 59a and 59b, the leaky coaxial cable 5 can be pressed by the pressing bodies 59a and 59b. Therefore, the leaky coaxial cable 5 placed on the cable support members 11, 11a, 11b can be stably fixed by the pressing force.

Further, the trough is formed by an anchor bolt 43 inserted into an existing long hole-shaped trough fixing bolt insertion hole 41 formed in the longitudinal direction of the trough body at substantially the center of the trough body 3a in the longitudinal direction and the width direction. The main body 3a can be easily fixed to the concrete ground 35. Further, a trough fixing bolt insertion hole 41 is formed at an arbitrary position of a groove between mutually opposed ribs 37 having a predetermined length along the longitudinal direction of the trough body, which is formed in the center of the back surface of the bottom portion 7 in the width direction. May be formed. Even in this case, the trough body 3a can be fixed to the concrete ground 35 by the anchor bolt 43 inserted into the trough fixing bolt insertion hole 41. Therefore, even if the fixing position of the anchor nut 45 provided on the concrete ground 35 is slightly displaced, the trough main body 3a can be easily fixed.

According to the present invention, the height and orientation of the slot can be kept constant, the influence of wind from a train or the like, the influence of water wetting or pollution, etc. can be suppressed, and the environmental temperature change and ultraviolet irradiation can be suppressed. Leaky coaxial cable laying structure, leaky coaxial cable laying method, leak coaxial cable trough body, polyolefin resin material with excellent flame retardancy and telecommunications characteristics, and trough structure of the material that can alleviate the deterioration of the cable due to It is possible to provide a method of use on the body and realize a communication method and a communication system using a laying structure of a leaky coaxial cable.

Good communication with the on-vehicle antenna can be performed by using the above communication method and communication system. Since a polyolefin resin material with excellent flame retardancy and telecommunications characteristics can be obtained, it can be used as a material for structures and members for telecommunications, and the material can be used as a trough material for leaky coaxial cables. By using the communication method and the communication system using the laying structure of the leaky coaxial cable of the present invention, it is possible to impart flame retardancy to the trough and to communicate with the on-vehicle antenna with low loss.

Although the embodiment of the present invention has been described above with reference to the attached figure focusing on the case where the trough length is 1 m, the technical scope of the present invention is the embodiment when the trough length is 1 m described in the specification. Not limited to, it can be applied to other trough lengths. In addition to the above, it is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea described in the claims, and of course, the present invention also relates to them. It is understood that it belongs to the technical scope.

For example, it goes without saying that the configurations of the embodiments can be combined with each other.

1, 1a, 1b, 1c, 1d, 1e ……… Leaky coaxial cable laying structure 3 ……… Trough 3a ……… Trough body 3b ……… Trough lid 5 ……… Leakage coaxial cable 7 ……… Bottom 9… ...... Side wall portions 11, 11a, 11b ...... Cable support members 13a, 13b ...... Connection portion 15 ...... Fixing bracket 17 ...... Bolt 19 ...... Internal conductor 21 ...... Insulator 21a ...... Insulator string 23 ………… Slot 25 ………… External conductor 27 ………… External sheath 29 ………… Support wire 31 ………… Cable connection 32 ………… Terminal connection 33 ………… Support 33a ………… Groove 34 ………… Feeding part 35 ………… Concrete ground 37 ………… Ribs 39a, 39b ………… Groove 41 ………… Trough fixing bolt insertion hole 43 ………… Anchor bolt 45 ………… Anchor nuts 47a, 47b ……… Inner rib 49 ………… Fixing part 51 ………… Trough structure 53 ………… Groove 55 ………… String-shaped fixing members 59a, 59b ………… Pressing body 61 ………… Notch

Claims (44)

With the resin trough body and trough lid,
The leaky coaxial cable housed in the trough body,
Equipped with
The trough body has a bottom portion and side wall portions that stand on both sides of the bottom portion, and is located at a predetermined position in the longitudinal direction of the trough in a closed space formed by the trough whose trough body is covered with the trough lid. A leaky coaxial cable, characterized in that a cable support member made of resin and / or rubber is arranged, and the leaky coaxial cable is placed on a support portion of the cable support member with the support wire facing downward. Laying structure. The trough body has a substantially U-shaped cross section, and connecting portions are formed at one end and the other end of the trough body and the trough lid, and by connecting the connecting portions, respectively. The leaky coaxial cable laying structure according to claim 1, wherein a plurality of the troughs can be connected. In a trough structure formed by connecting a predetermined number of the trough main body and the trough covered with the trough lid which are adjacent to each other, at a predetermined position in the longitudinal direction inside a closed space formed by the trough structure. A plurality of the cable support members are arranged at predetermined intervals, and the cable support members are provided on the support portions formed at a predetermined height of the cable support members in the cable support members arranged at any positions. The leaky coaxial cable laying structure according to claim 1 or 2, wherein the leaky coaxial cable is placed. The support portion of the cable support member is formed in a substantially semicircular shape so that the leaky coaxial cable can be accommodated, and the leaky coaxial cable is attached to the support portion of the cable support member from the bottom portion of the trough. The leaky coaxial cable laying structure according to claim 3, wherein the cable is supported at a predetermined height and at a predetermined angle. The leaky coaxial cable laying structure according to claim 3 or 4, wherein the cable support members are provided at intervals of 2 m or more and 6 m or less of the trough structure. At least a part of the support portions of the plurality of cable support members are alternately inverted and arranged so that the support portions are arranged at positions offset by a predetermined distance from the center in the width direction of the cable support members. The leaky coaxial cable is bent and loosely arranged in a substantially S shape on the cable support member so that continuous bent portions are alternately formed in the longitudinal direction of the trough structure. The leaky coaxial cable laying structure according to claim 5. When the outer conductor of the leaky coaxial cable is made of aluminum, the bending angle of the leaky coaxial cable loosely arranged in a substantially S shape is 2 ° or less and 0.5 ° or more, which is the maximum allowable bending angle of the outer conductor. The leaky coaxial cable laying structure according to claim 6, wherein the coaxial cable is laid. The leaky coaxial cable laying structure according to any one of claims 3 to 7, wherein the cable support member is made of resin and is integrally formed with the trough body. The cable support member is formed separately from the trough body, a fixing portion is formed inside the cross section of the trough, the cable support member is fixed to the fixing portion, and the fixing portion is an inner surface surface of the trough body. And / or the inner ribs facing each other formed so that the cable support member can be inserted and fixed to the inner bottom surface, and the cable support member is inserted and fixed between the inner ribs. The leaky coaxial cable laying structure according to any one of claims 3 to 7. The leaky coaxial cable mounted on the cable support member is bound to the cable support member by a string-shaped fixing member so that the leaky coaxial cable does not deform in cross section. The leaky coaxial cable laying structure according to any one of claims 3 to 9, wherein the leakage coaxial cable is fixed to a cable support member. When the trough lid is fixed to the trough body with a fixing bolt, a pressing body made of a polyethylene foam sheet is used in at least a part of the arrangement portion of the cable support member on which the leaky coaxial cable is placed. The leaky coaxial cable placed on the cable support member is placed on the leaky coaxial cable by pressing the pressing body within the range of 0.2% of the cross-sectional deformation distortion rate of the leaky coaxial cable. The leaky coaxial cable laying structure according to any one of claims 3 to 10, characterized in that it is fixed. When the trough lid is fixed to the trough body with a fixing bolt, a pressing body made of a polyethylene foam sheet is used in at least a part of the arrangement portion of the cable support member on which the leaky coaxial cable is placed. The leaky coaxial cable placed on the cable support member by pressing the pressing body on the leaky coaxial cable within a range of 0.2% of the cross-sectional deformation distortion rate of the leaky coaxial cable. The leaky coaxial cable laying structure according to any one of claims 3 to 10, wherein the pull-out force per 100 m can be fixed so as to be 300 kg or more. In a leaky coaxial cable laying structure in which a trough fixing bolt insertion hole is provided at the bottom of the trough body, and the trough body is fixed to concrete ground by an anchor bolt inserted through the trough fixing bolt insertion hole. ,
An existing long hole-shaped bolt insertion hole for fixing the trough formed in the longitudinal direction and the width direction of the trough body, or the center of the back surface of the bottom surface in the width direction. Anchor inserted into any of the trough fixing bolt insertion holes formed at any position of a groove between the ribs formed on the trough with predetermined lengths facing each other along the longitudinal direction of the trough. The claim is characterized in that when the trough body is fixed to the concrete ground by the bolt, the formation position of the trough fixing bolt insertion hole can be adjusted so as to correspond to the fixing position of the anchor bolt. The leaky coaxial cable laying structure according to any one of claims 3 to 12. By adjusting the connection angle of the connection portion of the trough body to at least one of the left-right direction and the up-down direction, the longitudinal direction of the trough body is adjusted by adjusting the bolt fixing position when the anchor bolt is inserted into the trough fixing bolt insertion hole. The leaky coaxial cable laying structure according to claim 13, wherein in addition to adjusting the distance of the forming position, it is possible to adjust both the positional deviation of the fixed position in the width direction and / or the vertical direction of the trough body. The farther the distance from the feeding point is between the connection portions that connect the leaky coaxial cables to each other, the more the slot arrangement angle of the leaky coaxial cable is set with respect to the cable axis direction at predetermined intervals of the leaky coaxial cable. The leaky coaxial cable laying structure according to any one of claims 3 to 12, wherein the slots are arranged at small arrangement intervals so that the slots become larger or have a higher density. The connection portion for connecting the leaky coaxial cables to each other is arranged at a position other than the arrangement portion of the cable support member of the trough structure, according to any one of claims 3 to 15. Leakage coaxial cable laying structure. The leaky coaxial cable is placed at a predetermined height on the resin cable support member inside the closed space formed by the trough structure formed by connecting the trough covered with the trough lid to the trough body. The communication characteristics under predetermined conditions in the 400 to 440 MHz band when placed at a predetermined angle are such that the leaky coaxial cable is placed at a predetermined height on the cable support member arranged on the concrete ground in the absence of the trough structure. Any of claims 3 to 16, characterized in that the transmission loss is within ± 2 dB / km and the coupling loss is within ± 2 dB when compared with the case where the cable is placed at a predetermined angle. Leaky coaxial cable laying structure described in Crab. As a test result in the communication characteristic confirmation test in the 400 to 440 MHz band of the trough structure, the trough is also used when the outer surface and the inner surface of the trough structure are wetted with water to absorb water. The same communication characteristics as when the outer and inner surfaces of the structure are in a dry state can be obtained, and the leaky coaxial cable is placed on the cable support member whose height is adjusted on the concrete ground in the absence of the trough structure. 17. Leakage according to claim 17, characterized in that the transmission loss is within ± 2 dB / km and the coupling loss is within ± 2 dB when compared with the case where the device is placed at a predetermined height and a predetermined angle. Coaxial cable laying structure. The leaky coaxial cable laying structure according to any one of claims 3 to 18, wherein the resin material forming the trough structure is a polyolefin-based recycled resin containing an inorganic substance or a polyolefin resin containing an inorganic substance. The dielectric constant of the polyolefin-based recycled resin forming the trough structure in the frequency 400 to 440 MHz band measured by the capacitance method is 3.15 or less, and the trough lid and the trough constituting the trough structure are formed. The leaky coaxial cable laying structure according to claim 19, wherein the maximum wall thickness of the main body is formed to be 10 mm or less. A resin trough body having a bottom portion and side wall portions erecting on both sides of the bottom portion and having a substantially U-shaped cross section, substantially in the center of the trough body in the longitudinal direction and the width direction, in the longitudinal direction of the trough body. An existing trough fixing bolt insertion hole formed toward the trough, or a rib facing each other having a predetermined length along the longitudinal direction of the trough is formed at the center of the back surface of the bottom surface in the width direction. When the trough body is fixed to the concrete ground by the anchor bolt inserted into any of the trough fixing bolt insertion holes formed at any position of the groove between the ribs, the fixing position of the anchor bolt A trough body for accommodating a leaky coaxial cable, which is characterized in that the formation position of the bolt insertion hole for fixing the trough can be adjusted so as to correspond to the above. The cable support member is inserted into the inner surface and / or inner bottom surface of the trough body at a predetermined position in the longitudinal direction of the trough body as a fixing portion for fixing the cable support member inside the cross section of the trough body. The trough body for accommodating a leaky coaxial cable according to claim 21, wherein inner ribs facing each other are formed so as to be fixed. 21. A 21st aspect of the trough body, wherein a cable support member for supporting the leaky coaxial cable is integrally formed with the trough body at a predetermined position in the longitudinal direction of the trough body. The trough body that houses the leaky coaxial cable described in. The trough body is covered with a resin trough lid, connecting portions are formed at one end and the other end of the trough body and the trough lid, and the trough lid is covered with the trough body. The method according to any one of claims 21 to 23, wherein the trough main body covered with a plurality of the trough lids can be connected by connecting the respective connecting portions. Trough body for storing leaky coaxial cables. 21. The trough body is made of a polyolefin resin material containing an inorganic substance, and the dielectric constant in the 400 to 440 MHz band measured by the capacitance method of the trough body is 3.15 or less. A trough body for accommodating the leaky coaxial cable according to any one of claims 24. The trough body for accommodating the leaky coaxial cable according to claim 25, wherein the trough body has mechanical properties such as a tensile strength of 20 MPa or more and a flexural modulus of 1000 MPa or more. The leakage coaxial according to claim 25 or 26, wherein the trough body has a characteristic that the Charpy impact value obtained by the Charpy impact test based on JIS K7110 is 5 kJ / m ^{2 or more as a mechanical characteristic.} Trough body for storing cables. 21 to 27, wherein the trough body has a water absorption rate of 0.15% or less after absorbing water at 23 ° C. for 24 hours, which is measured based on JIS K7209 equivalent to ASTM D570. A trough body that houses the leaky coaxial cable described in either. In a test in which immersion is performed at room temperature for 24 hours in accordance with JIS K7114, a immersion test of a 3% NaCl aqueous solution which is a seawater simulated solution, a 30% CaCl ₂ immersion test as a snow melting agent simulated solution, and an acidic rain simulated solution are used. In _{the immersion test with a test solution obtained by diluting a liquid obtained by mixing H 2} SO ₄ and _{H NO 3} at a ratio of 2: 1 to a concentration of 1%, the mass change rate of the resin forming the trough body was determined in all the tests. The trough body for accommodating the leaky coaxial cable according to any one of claims 21 to 28, which is 0.1% or less. ^{After the weather resistance acceleration test in which ultraviolet light with an irradiation intensity of 90 mW / cm 2} is irradiated for 2000 hours in an environment of 50% humidity, the residual tensile strength of the resin forming the trough body is ultraviolet light. Claimed from claim 21, wherein the tensile strength before irradiation is 95% or more, and the residual ratio of the Charpy impact value after the same ultraviolet irradiation is 90% or more of the Charpy impact value before ultraviolet light irradiation. A trough body for accommodating the leaky coaxial cable according to any one of item 29. A polyolefin-based recycled resin material containing inorganic substances.
It is characterized in that the dielectric constant containing at least magnesium hydroxide and titanium oxide as inorganic substances is 3.15 or less, and the content of magnesium hydroxide is 18% by mass or more with respect to the total mass of the polyolefin-based recycled resin material. A polyolefin-based recycled resin material with excellent flame retardancy and communication characteristics. The inorganic substances of the polyolefin-based recycled resin material containing the inorganic substances are three types of magnesium hydroxide, calcium carbonate, and titanium oxide, and the content ratio of each of the polyolefin-based recycled resin materials with respect to the total mass is magnesium hydroxide 18 to. It is contained in the range of 21.3% by mass, 14 to 16.5% by mass of calcium carbonate, and 2 to 2.2% by mass of titanium oxide, and the total content of the inorganic substances is the total mass of the polyolefin-based recycled resin material. The polyolefin-based recycled resin material having excellent flame retardancy and communication characteristics according to claim 31, which is 34% by mass or more and 40% by mass or less. The polyolefin-based resin material containing an inorganic substance according to claim 31 or 32, wherein the polyolefin-based recycled resin material uses a virgin resin as the polyolefin resin instead of the polyolefin-based recycled resin material. The polyolefin-based recycled material having excellent flame retardancy and communication characteristics according to any one of claims 31 to 33, wherein the polyolefin-based recycled resin material is a material for a structure or a member for telecommunications. Resin material. A method for using a polyolefin-based recycled resin material, which comprises using the polyolefin-based recycled resin material according to claim 31 or 32 for a trough structure. It is a method of laying a leaky coaxial cable.
A step of fixing a resin trough body having a bottom portion and side wall portions standing on both sides of the bottom portion and having a substantially U-shaped cross section to concrete ground.
A process of arranging a leaky coaxial cable with a support wire facing downward on a support portion of a cable support member arranged inside the trough body.
Equipped with
In the step of fixing to the concrete ground, an existing long hole-shaped insertion hole formed in the longitudinal direction and the width direction of the trough body is formed at substantially the center in the longitudinal direction and the width direction of the trough body, or the back surface of the bottom portion. It is characterized in that the trough is fixed to the concrete ground by inserting an anchor bolt into any of the insertion holes formed between the ribs facing each other having a predetermined length along the trough longitudinal direction in the center in the width direction. How to lay a leaky coaxial cable. In the step of fixing the trough body to the concrete ground, connecting portions are formed at one end and the other end of the trough body, and the connecting portions are connected to each other at a predetermined angle in the width direction and / or the vertical direction. The method for laying a leaky coaxial cable according to claim 36, wherein it is possible to lay the anchor nut so as to absorb the misalignment of the forming position of the anchor nut provided on the concrete ground by connecting the cable at an angle to the above. .. In the step of arranging the cable support member inside the trough main body and arranging the leaky coaxial cable in the support portion of the cable support member with the support wire facing downward, the cable support member is the cable support. The support portion of the member is formed so as to be offset from the center of the cable support member by a predetermined distance, and the adjacent cable support members are alternately inverted and arranged so that the leaky coaxial cable is substantially attached to the support portion on the support member. The method for laying a leaky coaxial cable according to claim 36 or 37, which comprises a step of loosely arranging the cable in an S shape. 38. The bending angle of the leaky coaxial cable is 2 ° or less and 0.5 ° or more, which is the maximum allowable bending angle of the outer conductor when the outer conductor of the leaky coaxial cable is aluminum. Leaky coaxial cable laying structure described in.

Further, by arranging a resin trough lid on the upper part of the trough main body and closing the trough, pressing made of a polyethylene foam sheet at least a part of the arrangement portion of the cable support member on which the leaky coaxial cable is placed. By pressing the leaky coaxial cable with the body within a range where the cross-sectional deformation distortion rate of the leaky coaxial cable is within a range of 0.2%, the pulling force of the leaky coaxial cable mounted on the cable support member per 100 m. The method for laying a leaky coaxial cable according to any one of claims 36 to 39, further comprising a pressing step capable of pressing and fixing the cable so as to have a weight of 300 kg or more. In the leakage coaxial cable laying structure according to any one of claims 3 to 17, a polyolefin-based material having a dielectric constant of 3.15 or less in the frequency 400 to 440 MHz band of a resin material containing an inorganic substance constituting the trough structure. A leaky coaxial cable laying structure that is a recycled resin and is characterized in that communication is performed in the frequency band of the 400 MHz band between the leaky coaxial cable mounted inside the trough structure and the on-vehicle antenna of the train. Communication method used. The transmission loss is ± 2 dB / km as compared with the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member whose height is adjusted on the concrete ground without using the trough structure. The communication method using the leaky coaxial cable laying structure according to claim 41, wherein it is possible to obtain communication characteristics within a range of within ± 2 dB of a coupling loss. Using the leaky coaxial cable laying structure according to any one of claims 3 to 17, the resin material containing an inorganic substance constituting the trough structure in the leaky coaxial cable laying structure is dielectric in the frequency 400 to 440 MHz band. It is a polyolefin-based recycled resin with a rate of 3.15 or less, and has a frequency of 400 MHz band between the leaky coaxial cable mounted inside the trough structure having a dielectric constant of 3.15 or less and the on-vehicle antenna of the train. A communication system using a leaky coaxial cable laying structure, which is characterized by performing communication in a band. The transmission loss is ± 2 dB / km as compared with the case where the leaky coaxial cable is placed at a predetermined height and a predetermined angle on the cable support member whose height is adjusted on the concrete ground without using the trough structure. The communication system using the leaky coaxial cable laying structure according to claim 43, wherein it is possible to obtain communication characteristics within ± 2 dB of a coupling loss.

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