JP2017132291A - Rfid tag built-in tire - Google Patents

Abstract

A tire with a built-in RFID tag that can secure a sufficient communication distance and has excellent durability is provided. In a tire including an RFID tag (10) including an RFID chip (11) and an antenna (12), the antenna (12) is connected to the outside of the first antenna (16) and the first antenna (16) connected to the RFID chip (11). The RFID tag 10 includes a second antenna 17 provided and electromagnetically coupled to the first antenna 16, and the RFID chip 11 and the first antenna 16 are fixed to the first fixing member 13. Is arranged on the outer side in the tire radial direction of the end of the carcass ply of the tire, and the second antenna 17 is electromagnetically coupled to the conductive carcass ply cord 7a constituting the carcass ply. [Selection] Figure 2

Description

  The present invention relates to a tire with a built-in RFID tag.

Conventionally, an RFID chip is embedded in an extension line on the free end side of the carcass ply inside the tire, and the carcass ply cord is extended from both ends of the RFID chip in the circumferential direction of a circle having a center on the tire center axis. And a dipole antenna that is electromagnetically coupled, and a method of reading tire information stored in an RFID chip by wireless communication is performed (for example, see Patent Documents 1 and 2).
Further, a transponder is known in which a circuit board having a transmission / reception function and a storage function and an antenna coil are housed and integrated in a cylindrical container (for example, see Patent Document 3).

JP 2008-265750 A JP 2005-535497 A JP 2006-56443 A

According to the methods described in Patent Documents 1 and 2, since the dipole antenna and the carcass ply are electromagnetically coupled, it is possible to secure a sufficient communication distance, but the dipole antenna is located near the bead portion. As a result, when the tire is greatly deformed, such as when the rim is assembled or when the protrusion is mounted, the joint between the RFID chip and the antenna is damaged and communication is not possible. As a result, the data is stored in the RFID chip. There was a problem that information could not be read.
On the other hand, in the transponder described in Patent Document 3, the joint between the RFID chip and the antenna is not easily damaged, but since the communication distance is short, in the case of a multi-wheel such as a large truck, information on the inner tire is used. In order to read, a special reading device (reader) was required.
Further, in Patent Document 3, an identification mark is provided on the outer surface of the tire where the transponder is arranged so that the position of the transponder can be confirmed. However, even if the identification mark is provided, the vehicle can be easily viewed. The operability was bad.

  The present invention has been made in view of conventional problems, and an object of the present invention is to provide a tire with a built-in RFID tag that can secure a sufficient communication distance and is excellent in durability.

The present invention is a tire including an RFID tag including an RFID chip and an antenna, wherein the antenna is provided outside the first antenna and the first antenna connected to the RFID chip. A second antenna that is electromagnetically coupled to the first antenna, the RFID chip and the first antenna are fixed to a first fixing member, and the RFID tag is connected to the carcass ply of the tire. The second antenna is disposed on the outer side in the tire radial direction at the end, and is electromagnetically coupled to a conductive carcass ply cord constituting the carcass ply.
Thus, since the antenna is electromagnetically coupled to the carcass ply cord, a sufficient communication distance can be ensured.
In addition, the second antenna, which is a part that is electromagnetically coupled to the carcass ply cord of the antenna, is electromagnetically coupled to the first antenna that is a part connected to the RFID chip of the antenna. Further, since the joining portion that is easily damaged when the tire is greatly deformed is eliminated, the durability of the RFID tag is improved.

In addition, since the extension direction of the second antenna and the extension direction of the carcass ply cord are orthogonal to each other, the second antenna and the carcass ply cord can be sufficiently electromagnetically coupled. Therefore, the communication distance of the RFID tag can be further increased.
Note that “perpendicular” means that the angle formed by the extension direction of the second antenna and the extension direction of the carcass ply cord is in a range of approximately 90 ° (90 ° ± 10 °).
Further, since the shape of the portion of the second antenna that is away from the first antenna by a predetermined distance or more is a corrugated shape, damage to the antenna due to deformation can be reduced.
Further, since the length of the portion of the second antenna that is within a predetermined distance from the first antenna is set to be half or more of the outer circumference of the first antenna, the first antenna and the second antenna Can be reliably coupled to each other, and a sufficient communication distance can be secured.
Further, the RFID chip, the first antenna, and at least a portion of the second antenna that is electromagnetically coupled to the first antenna are covered from the side opposite to the first fixing member. Since the second fixing member is provided to relieve the stress acting on the RFID tag, the durability can be further improved.

  The summary of the invention does not list all necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

It is a figure showing a tire concerning an embodiment of the invention. It is a figure which shows the RFID tag by this invention. It is a figure which shows the detail of the 1st and 2nd antenna. It is a figure which shows the relationship with the 1st and 2nd antenna. It is a figure which shows the relationship between an RFID tag and a carcass ply. It is a figure which shows the relationship between the direction of an antenna and a carcass ply. It is a figure which shows the conventional RFID tag.

FIG. 1 shows a tire 1 according to the present embodiment, in which 2 is a tread portion, 3 is a belt layer, 4 is a sidewall portion, 5 is a shoulder portion, 6 is a bead portion, 7 is a carcass ply, 1 is an RFID tag according to the present invention.
The tread portion 2 is a portion where the tire 1 is in contact with the road surface, and is formed of a thick rubber layer. A tread pattern is formed on the surface of the rubber layer.
The belt layer 3 is formed by covering a cord with a rubber member, and a plurality of layers are arranged between the tread portion 2 and the carcass ply 7 in order to have a “definite effect” for maintaining rigidity in the tire circumferential direction.
The sidewall portion 4 is a rubber layer provided between the tread portion 2 and the bead portion 6, and the shoulder portion 5 is a rubber layer on the sidewall portion 4 side of the tread portion 2.
The bead portion 6 includes a pair of bead cores 6 a and bead fillers 6 b, and is disposed symmetrically with respect to a plane perpendicular to the tire central axis passing through the center of the tire 1.
The bead core 6a is formed by forming a bundle of steel wires in a ring shape and covered with a rubber member. The cross section filled between the carcass ply 7 is a triangular rubber member.
The carcass ply 7 is a member that forms a tire skeleton, and includes a plurality of conductive cords (hereinafter referred to as carcass ply cords) 7a and a covering rubber 7b that covers the carcass ply cord 7a. Are arranged so as to straddle the bead core 6a.
Both ends of the carcass ply 7 are bent around the bead core 6a from the inside to the outside of the tire 1 to form a bent portion 7c.
As will be described later, the carcass ply cord 7a is electromagnetically coupled to the antenna 12 of the RFID tag 10 via the rubber member constituting the bead filler 6b that is a dielectric and the covering rubber 7b, and functions as an antenna of the RFID tag 10.
As shown in FIG. 2, the RFID tag 10 includes an RFID chip 11, an antenna 12 connected to the RFID chip 11, and first to third fixing members 13 to 15. It is attached on the inside and communicates with a reader not shown (see FIG. 1).
In this example, the mounting position of the RFID tag 10 is 30 mm above the bead core 6a, 10 mm below the upper end of the bead filler 6b, and 4 mm outside the carcass ply cord 7a.

The antenna 12 includes a first antenna 16 connected to the RFID chip 11 and a second antenna 17 provided outside the first antenna 16.
In this example, as shown in FIG. 3A, the first antenna 16 is a rectangular double loop antenna for the purpose of expanding the bandwidth of the used frequency.
The RFID chip 11 and the first antenna 16 are formed on a first fixing member 13 which is a film substrate such as PET.
Here, let the paper surface side of FIG.2 and FIG.3 be a tire outer surface side, and let the back side of a paper surface be a tire inner surface side.
In this example, the RFID chip 11 and the first antenna 16 are placed on the first fixing member so that the RFID chip 11 and the first antenna 16 are located on the tire outer surface side, and the first fixing member 13 is located on the tire inner surface side. 13 formed.
Hereinafter, the horizontal direction in FIGS. 2 and 3 is referred to as the horizontal direction (also referred to as the horizontal direction), and the vertical direction is referred to as the vertical direction (also referred to as the vertical direction). The horizontal direction is the circumferential direction of the tire 1, and the vertical direction is the radial direction of the tire 1.
In this example, the first fixing member 13 is a film having a length of a ₁ = 6 mm, a width of a ₂ = 7 mm, and a thickness of t = 0.1 mm. However, the shape and dimensions of the first fixing member 13 The length may be appropriately determined depending on the size and shape of the RFID chip 11 and the first antenna 16.

As shown in FIG. 3B, the second antenna 17 includes a U-shaped electromagnetic field coupling portion 17a and a pair of extension portions 17b extending left and right from both ends of the electromagnetic field coupling portion 17a. With.
The extension direction of the extension portion 17b is not particularly limited, but is preferably a direction orthogonal to the extension direction of the carcass ply cord 7a that is a conductive cord.
Further, if the shape of the extension portion 17b is a corrugated shape, and the corrugated folded portion is R-attached, the spring property of the second antenna 17 can be improved, so that the breakage of the second antenna 17 is reduced. The durability of the RFID tag 10 can be further improved.
The total length L ₁₇ of the second antenna 17 is preferably ¼ or more of the wavelength of the communication frequency in order to secure a communication distance. As the communication frequency, 2.45 GHz and UHF band (860 to 960 MHz) are mainly used. In this example, the communication frequency is 920 MHz, and the total length L ₁₇ of the second antenna ₁₇ is 128 mm (2/5 wavelength). It was.

In this example, as shown in FIG. 3C, the RFID chip 11, the first antenna 16, and the electromagnetic field coupling portion 17 a of the second antenna 17 are fixed by the second fixing member 14. ing. As the 2nd fixing member 14, what apply | coated the adhesive agent to the fixed surface side of the coating | covering material which consists of synthetic resins, such as nylon, is used suitably.
The second fixing member 14 fixes the RFID chip 11, the first antenna 16, and the electromagnetic field coupling portion 17 a of the second antenna 17 on the side opposite to the first fixing member 13. Thereby, the positional deviation between the first antenna 16 and the second antenna 17 can be prevented, and the RFID chip 11 formed on the first fixing member 13 and the first antenna 16 are connected to each other. Since it is covered with the two fixing members 14, bending stress is hardly applied.
Therefore, the durability of the RFID tag 10 can be greatly improved. In addition, even if the second antenna 17 is damaged, the connection portion between the RFID chip 11 and the first antenna 16 is hardly damaged. Therefore, the RFID chip 11 is not taken out and stored in the RFID chip 11. Information can be confirmed.
The RFID chip 11, the first antenna 16, and the electromagnetic field coupling portion 17 a of the second antenna 17 are connected to the second fixing member 13 from both the side opposite to the first fixing member 13 and the first fixing member 13. The fixing member 14 may be covered.

Also, as shown in FIG. 4, it is preferable that the outer loop of the first antenna 16 and the U-shaped electromagnetic field coupling portion 17a are substantially parallel and close to each other.
Specifically, the distance d ₁₂ between the outer loop of the first antenna 16 and the U-shaped electromagnetic field coupling portion 17a is set to 2 mm or less and close to the first antenna 16 of the second antenna 17. It is preferable that the total length L ₂ of the region (d ₁₂ ≦ 2 mm) is not less than ½ of the outer peripheral length L ₁ of the first antenna 16. Thereby, the first antenna 16 and the second antenna 17 can be reliably electromagnetically coupled.
The dimension length of the second fixing member 14 may be larger than that of the first fixing member 13 and at least the size including the electromagnetic field coupling portion 17a of the second antenna 17, and the extension portion. A part of 17b may be included. In this example, the vertical length of the second fixing member 14 is b ₁ = 10 mm, the horizontal length is b ₂ = 10 mm, and the thickness is T = 1 mm.

By the way, if the diameter of the carcass ply cord 7a is 1 mm and the interval is 1 mm, the second antenna 17 intersects with about 60 carcass ply cords 7a.
Since the carcass ply cord 7a is a conductive cord, as shown in FIG. 5, if the distance D between the second antenna 17 and the carcass ply cord 7a is in the range of 2 mm to 15 mm, the second antenna 17 And the carcass ply cord 7a can be sufficiently electromagnetically coupled. That is, the carcass ply cord 7a can function as the third antenna of the RFID tag 10.
When D <2 mm, the carcass ply cord 7a and the antenna 12 are sufficiently electromagnetically coupled, but the antenna 12 and the carcass ply cord 7a are too close to each other, so that the antenna is greatly deformed. 12 (particularly, the second antenna 17) may be damaged. On the other hand, when D> 15 mm, electromagnetic field coupling between the carcass ply cord 7a and the antenna 12 is insufficient, and thus the communication distance is shortened.
In this example, D = 4 mm as described above. However, if D is within the above range, the antenna 12 and the carcass ply cord 7a can be appropriately electromagnetically coupled without impairing the durability. The ply cord 7a can function as the third antenna of the RFID tag 10.
Further, since each carcass ply cord 7a as the third antenna is electromagnetically coupled to the adjacent carcass ply cord 7a, not only the tire side surface in which the RFID tag 10 is embedded, but also the tire upper surface and the RFID tag. Communication with an external communication device such as a reader is also possible on the side opposite to the side where 10 is embedded.

  Furthermore, in this example, as shown in FIGS. 2 and 5, the RFID chip 11 and the antenna 12 (the first antenna 16 and the second antenna 17) are connected to a third fixing member 15 made of a rubber sheet. Since the RFID tag 10 can be reliably prevented from being damaged, the RFID tag 10 is incorporated into the tire 1 after the RFID chip 11 and the antenna 12 are enclosed by the third fixing member 15. If so, the RFID tag 10 can be easily incorporated into the tire 1 without fear of damage.

Thus, in the present embodiment, the antenna 12 of the RFID tag 10 is electromagnetically coupled to the first antenna 16 connected to the RFID chip 11 and the carcass ply cord 7a that functions as the antenna of the RFID tag 10. And the second antenna 17 is extended in a direction orthogonal to the extending direction of the carcass ply cord 7a and the electromagnetic field coupling portion 17a that electromagnetically couples with the first antenna 16. Since the extension portion 17b is used, a long communication distance can be secured and the durability of the RFID tag 10 can be improved.
Since the RFID chip 11, the first antenna 16, and the electromagnetic field coupling portion 17a of the second antenna 17 are covered with the second fixing member 14, the bending stress when the tire is deformed is relieved. The durability of the RFID tag 10 can be greatly improved.

表１から、第２のアンテナ１７とカーカスプライコード７ａとが直交している場合に、通信距離が最大となることがわかった。
また、図６に示す本発明によるＲＦＩＤタグ１０の通信距離と、図７に示すような、ＲＦＩＤチップ５１と螺旋形のアンテナ５２とが物理的に結合している従来型のＲＦＩＤタグ５０との通信距離とを比較した。従来型のＲＦＩＤタグ５０のアンテナ５２の延長方向と図示しないカーカスプライコードとのなす角度は、本発明によるＲＦＩＤタグ１０と同じく９０°である。
従来型のＲＦＩＤタグ５０の仕様を以下の表２に、比較結果を表３に示す。
通信距離は、ＲＦＩＤタグ１０及びＲＦＩＤタグ５０を、厚さ２ｍｍのゴムシートで挟み込み、カーカスプライコードと第２のアンテナ１７との距離、及び、カーカスプライコードとアンテナ５２との距離が５ｍｍになる位置に設置して測定した。なお、ゴムシートとしては、ＣＢを２０重量部、Ｓｉを３重量部含むゴムを使用した。
通信距離は、従来型のＲＦＩＤタグ５０の値を１００としたときの指数である。

表３に示すように、本発明のＲＦＩＤタグ１０は、従来型のＲＦＩＤタグ５０の約１０倍の通信距離を確保できることがわかる。
これは、本発明のＲＦＩＤタグ１０は、第２のアンテナ１７がＲＦＩＤチップ１１と物理的に結合していないので、アンテナ長（全長）を長くすることで、カーカスプライコード７ａと十分な電磁界結合をさせることができるのに対し、従来型のＲＦＩＤタグ５０では、耐久性の関係で全長を長くできないので、カーカスプライコードとの十分な電磁界結合がなされないからであると考えられる。
また、従来型のＲＦＩＤタグ５０では、アンテナ５２を螺旋状として計算上のアンテナ長を長くしているが、その効果は少ないと考えられる。 [Example]
As shown in FIG. 6, angles formed by the second antenna 17 of the RFID tag 10 according to the present invention and the carcass ply cord 7a as the third antenna (hereinafter referred to as the antenna angle α) are 0 °, 30 °, Table 1 below shows the results of measuring the communication distance when the angle is 60 ° and 90 ° (orthogonal).
The communication distance is an index when α = 0 ° is taken as 100.

From Table 1, it was found that the communication distance was maximum when the second antenna 17 and the carcass ply cord 7a were orthogonal.
Also, the communication distance of the RFID tag 10 according to the present invention shown in FIG. 6 and the conventional RFID tag 50 in which the RFID chip 51 and the helical antenna 52 are physically coupled as shown in FIG. The communication distance was compared. The angle formed between the extending direction of the antenna 52 of the conventional RFID tag 50 and a carcass ply cord (not shown) is 90 ° as in the RFID tag 10 according to the present invention.
The specifications of the conventional RFID tag 50 are shown in Table 2 below, and the comparison results are shown in Table 3.
As for the communication distance, the RFID tag 10 and the RFID tag 50 are sandwiched between rubber sheets having a thickness of 2 mm, and the distance between the carcass ply cord and the second antenna 17 and the distance between the carcass ply cord and the antenna 52 are 5 mm. Measured by installing in position. As the rubber sheet, a rubber containing 20 parts by weight of CB and 3 parts by weight of Si was used.
The communication distance is an index when the value of the conventional RFID tag 50 is 100.

As shown in Table 3, it can be seen that the RFID tag 10 of the present invention can secure a communication distance of about 10 times that of the conventional RFID tag 50.
In the RFID tag 10 of the present invention, since the second antenna 17 is not physically coupled to the RFID chip 11, the carcass ply cord 7a and a sufficient electromagnetic field can be obtained by increasing the antenna length (full length). It can be considered that the conventional RFID tag 50 cannot be made long because of its durability, and the electromagnetic field coupling with the carcass ply cord cannot be sufficiently performed.
Further, in the conventional RFID tag 50, the antenna 52 is formed in a spiral shape to increase the calculated antenna length, but it is considered that the effect is small.

  As mentioned above, although this invention was demonstrated using embodiment and an Example, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the embodiment. It is apparent from the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

For example, in the above-described embodiment, the passive RFID tag 10 that performs wireless communication with a reader that reads tire data has been described. However, the present invention is an active type that transmits and receives data to and from a reader / writer. It can also be applied to other RFID tags.
In the above embodiment, the RFID tag 10 is mounted 30 mm above the bead core 6a and 10 mm below the upper end of the bead filler 6b. However, the mounting location of the RFID tag 10 is not limited to this, What is necessary is just between bead core 6a and bead filler 6b. Note that the distance D between the RFID tag 10 and the carcass ply cord 7a is preferably in the range of 2 mm to 15 mm as described above.
Moreover, in the said embodiment, although the shape of the extension part 17b of the 2nd antenna 17 was made into the waveform, it is good also as a spiral. Thereby, since the spring property of the 2nd antenna 17 can further be improved, durability of the RFID tag 10 can be improved further.

1 tire, 2 tread part, 3 belt layer, 4 side wall part,
5 shoulder part, 6 bead part, 6a bead core, 6b bead filler,
7 Carcass ply, 7a Carcass ply cord, 7b Cover rubber,
7c bending part, 10 RFID tag, 11 RFID chip, 12 antenna,
13-15 1st-3rd fixing member, 16 1st antenna, 17 2nd antenna,
17a Electromagnetic field coupling part, 17b extension part.

Claims (5)

A tire incorporating an RFID tag having an RFID chip and an antenna,
A first antenna connected to the RFID chip;
A second antenna provided outside the first antenna and electromagnetically coupled to the first antenna;
The RFID chip and the first antenna are fixed to a first fixing member,
The RFID tag is
It is arranged on the tire radial direction outer side of the end of the carcass ply of the tire,
The second antenna is
An RFID tag built-in tire characterized by being electromagnetically coupled to a conductive carcass ply cord constituting the carcass ply.   2. The RFID tag built-in tire according to claim 1, wherein an extension direction of the second antenna and an extension direction of the carcass ply cord are orthogonal to each other.   3. The RFID tag built-in tire according to claim 1, wherein a shape of a portion of the second antenna away from the first antenna by a predetermined distance or more is a corrugated shape. 4.   4. The length of a portion of the second antenna that is within a predetermined distance from the first antenna is not less than half the length of the outer periphery of the first antenna. The RFID tag built-in tire according to any one of the above.   A second covering the RFID chip, the first antenna, and a portion of the second antenna that is electromagnetically coupled to at least the first antenna from the side opposite to the first fixing member. The RFID tag built-in tire according to claim 1, further comprising a fixing member.

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