Patent Description:
Contactless RFID (Radio Frequency Identification) tags configured to write and read information using electromagnetic waves are widely used.

An aircraft tire is managed by attaching the RFID tag to the aircraft tire, and writing and reading information related to the tire.

For example, Patent Literature <NUM> discloses a structure of an aircraft tire in which the RFID tag is embedded in a crown region thereof and a dipole antenna is disposed in an axial direction.

As a further example, Patent Literature <NUM> discloses a tire assembly with integrated electronic components that includes a tire structure and an integrated electronics assembly, which preferably includes at least a radio frequency (RF) device and a multi-frequency antenna that enables wireless communication in at least first and second resonant frequency bands. Such multi-frequency antenna further comprises at least first and second antenna wires connected to the RF device, thus facilitating the transmission of RF signals which may include information such as tire identification information or measured condition information such as tire temperature, pressure, and other characteristics. The first and second antenna wires preferably function together as at least two dipole antennas, for example, two half-wave dipole antennas or one half-wave dipole antenna and one three-half-wave dipole antenna.

However, when a size (diameter) of the tire is large, for example, <NUM> inches or more, the above-described conventional aircraft tire may have a problem that a communication performance deteriorates due to attenuation of electromagnetic waves or the like caused by a large tire width.

An object of the present invention is to provide an aircraft tire that improves RIFD tag communication performance even when a size is <NUM> inches or larger.

One or more embodiments of an aircraft tire (T) according to present invention has a pair of bead sections (<NUM>), sidewall sections (<NUM>) extending from outer side in a radial direction of the bead section, and a tread section (<NUM>) extending between the sidewall sections; the aircraft tire includes an RFID tag (<NUM>) having a tag main body (<NUM>) configured to store information about the aircraft tire, and an antenna (A1, A2) extended from the tag main body; wherein, in a tread surface view, the antenna is disposed such that an extending direction (D1) of the antenna is parallel to a tire width direction or intersects the tire width direction (D2) within a predetermined angle range, and the aircraft tire satisfies a relationship <NUM><L/W <<NUM>, where a width of the aircraft tire is denoted as "W" and a total length of the antenna in the extending direction of the antenna is denoted as "L", and when a diameter of the aircraft tire is <NUM> inches or more.

According to such a configuration, the communication performance of the RFID tag can be improved by satisfying the above relationship to reduce attenuation of electromagnetic waves or the like, even when the size thereof is <NUM> inches or more.

An aircraft tire T according to an embodiment of one or more embodiments will be described with reference to <FIG>.

In the following drawings, the same or similar parts are denoted by the same or similar numerals. However, it should be noted that the drawings are schematic, and the ratio of each dimension and the like may be different from the actual figures.

Therefore, specific dimensions should be determined in consideration of the following description. Further, it is needless to say that portions having different dimensional relationships and ratios among the drawings are included.

An example of a configuration of an aircraft tire T will be described with reference to <FIG> and <FIG>.

<FIG> is a cross-sectional view in a tread width direction illustrating a schematic configuration of the aircraft tire T according to one or more embodiments; and <FIG> is a perspective view illustrating a schematic configuration of the aircraft tire T.

The aircraft tire T includes a bead section <NUM> to be in contact with a wheel <NUM>, a carcass <NUM> as a frame of the aircraft tire T, a plurality of belt parts <NUM> disposed on an outer side in a tire radial direction of the carcass <NUM>, and a tread section <NUM> disposed on an outer side in the tire radial direction of the belt part <NUM> and configured to be in contact with a road surface. A sidewall section <NUM> extending from an outer side in a radial direction of a pair of the bead sections <NUM>.

As illustrated in <FIG>, a tire inner surface <NUM> of the aircraft tire T according to the present embodiment is provided with an RFID tag <NUM> including an IC chip <NUM> as a tag main body configured to store information (information such as serial number, size, and proper internal pressure) about the aircraft tire T and antennas A1 and A2 extended from the IC chip <NUM>.

More specifically, the RFID tag <NUM> is formed by sealing the IC chip <NUM> and the antennas A1 and A2 within a rubber patch <NUM>, and is attached to the tire inner surface <NUM> by an adhesive.

As illustrated in <FIG>, the antennas A1 and A2 are disposed such that their extending direction D1 is parallel to a tire width direction D2 or intersects the tire width direction D2 within a predetermined angle range (For example, within <NUM> degrees) in a tread surface view.

Further, the aircraft tire satisfies a relationship <NUM>< L/W <<NUM>, where a width of the aircraft tire is denoted as "W" and a total length (L1, L2) of the antennas in the extending direction D1 is "L", and when a diameter of the aircraft tire T is <NUM> inches or more.

A RFID reader/writer <NUM> illustrated in <FIG> is configured to transmit and receive information to and from the RFID tag <NUM>.

The RFID reader/writer <NUM> includes a communication antenna <NUM> and an information display part <NUM> having a liquid crystal display, etc.; and the RFID reader/writer <NUM> is configured to display and review information (information such as serial number, size, and proper internal pressure) about the aircraft tire T read from the RFID tag <NUM>.

With such a configuration, when the diameter of the aircraft tire T is <NUM> inches or more, the attenuation of electromagnetic waves in the aircraft tire T reduces and improves the communication performance of the RFID tag. Measurement examples for reviewing the communication performance of the aircraft tire T will be described later.

When a balance patch is provided on the tire inner surface <NUM>, the RFID tag <NUM> is disposed circumferentially apart from the balance patch. Thus, the RFID tag <NUM> can be provided in the aircraft tire T while maintaining the balance of the aircraft tire T.

The belt part <NUM> disposed in the tread section <NUM> may be made of a non-metal material. With such a configuration, the attenuation of electromagnetic waves between the RFID tag <NUM> and the RFID reader/writer <NUM> or the like may reduce, thereby may improve the communication performance.

Further, by attaching the RFID tag <NUM> to the tire inner surface <NUM>, the bead section <NUM> can function as an antenna, and the communication performance is further improved. Moreover, the sensitivity of the RFID tag <NUM> is enhanced by the reflection of the electromagnetic wave at the bead section <NUM>.

Referring to <FIG>, a configuration example of the RFID tag <NUM> applicable to the aircraft tire T according to the present embodiment will be described.

<FIG> is a schematic configuration diagram illustrating a configuration example of an RFID tag <NUM> to be applied to the aircraft tire T according to the present embodiment; and <FIG> is a block diagram illustrating an internal configuration of the RFID tag <NUM>.

As illustrated in <FIG>, the RFID tag <NUM> is formed by sealing the IC chip <NUM> and the antennas A1 and A2 within the rubber patch <NUM>. An adhesive layer is provided on a back surface of the rubber patch <NUM> so as to be attached to the tire inner surface <NUM>.

As illustrated in <FIG>, the RFID tag <NUM> includes the antennas A1, A2, a transmitter/receiver (transceiver) <NUM> including an RF circuit and a power supply circuit, a CPU <NUM> as a controller, a memory <NUM> including a nonvolatile memory ROM, and a memory <NUM> including a volatile memory (RAM).

The antennas A1 and A2 communicate with the RFID reader/writer <NUM> and the like. The antennas A1 and A2 also serve as power receiving devices configured to feed electrical power to the transmitter/receiver <NUM> or the like depending on radio signals from the RFID reader/writer <NUM> or the like.

The transmitter/receiver <NUM> modulates/demodulates data transmitted/received by the RF circuit, and feeds electrical power to the CPU <NUM> or the like by the power supply circuit.

In accordance with the command received from the antennas A1 and A2, the CPU <NUM> performs processing such as responding to data (Serial number, size, proper internal pressure, etc.) about the aircraft tire T or a unique ID recorded in the memory <NUM>.

The memory <NUM> is used as a work area of the CPU <NUM>.

Referring to <FIG> and <FIG>, a configuration example of the antenna in the RFID tag <NUM> will be described.

Antennas A1 and A2 illustrated in <FIG> are formed to be a so-called dipole antenna in which antenna lines having linear shape and same length (L1, L2) extends from right and left ends of the IC chip <NUM>. The antenna wire may be formed of a coil winding.

In the antennas A1 and A2 illustrated in <FIG>, the parameter L (the total length of the antenna in the extending direction of the antenna) under the relationship of <NUM> < L/W < <NUM> is expressed by L = L1 + L2.

The antenna A3 illustrated in <FIG> is a so-called monopole antenna in which an antenna line having a linear shape and having a length L3 extends from a right end of the IC chip <NUM>. The antenna wire may be formed of a coil winding.

In the antenna A3 of a RFID tag 10a illustrated in <FIG>, the parameter L in the relationship of <NUM> < L/W < <NUM> is expressed by L = L3.

The antennas A4 a and A4b of the RFID tag 10b illustrated in <FIG> are formed to be a so-called dipole antenna in which antenna lines having wavy-line shape extends from left and right ends of the IC chip <NUM>.

The distances L4 and L5 from the end of the IC chip <NUM> to the ends of the antennas A4a and A4b are made the same.

In the antennas A4a and A4b illustrated in <FIG>, the parameter L under the relationship of <NUM> < L/W < <NUM> is expressed by L = L4 + L5.

Measurement examples of communication distance of the RFID tags <NUM> will be described with reference to <FIG>.

<FIG> is a graph depicting communication distances of experimental RFID tags (A) to (C) or the like for an aircraft tire (<NUM> inches) according to the present embodiment; and <FIG> is a graph depicting communication distances of experimental RFID tags (A) to (C) or the like for an aircraft tire (<NUM> inches) according to a comparative example.

For measurements, three experimental RFID tags (A) to (C) with different lengths of the antennas (antenna width) A1 and A2 are prepared as the RFID tag <NUM> having a dipole antenna illustrated in <FIG>.

Here, a length of antennas (antenna width) of the experimental RFID tag (A) is <NUM>, a length of the antenna (antenna width) of the experimental RFID tag (B) is <NUM>, and a length of antenna (antenna width) of the experimental RFID tag (C) is <NUM>.

An aircraft tire (<NUM> inches) as a comparative example and the aircraft tire (<NUM> inches) are prepared, and the experimental RFID tags (A) to (C) are attached to the tire inner surface <NUM> as illustrated in <FIG> such that the extending direction D1 of the antennas A1 and A2 are parallel to the tire width direction D2 or intersect the tire width direction D2 within a predetermined angle range (For example, within <NUM> degrees), and the communication distance readable by the RFID reader/writer <NUM> are measured.

With the aircraft tire (<NUM> inches), the communication distance of the experimental RFID tag (A) is approximately <NUM>, the communication distance of the experimental RFID tag (B) is approximately <NUM>, and the communication distance of the experimental RFID tag (C) is approximately <NUM>.

By contrast, with the aircraft tire (<NUM> inches), the communication distance of the experimental RFID tag (A) is approximately <NUM>, the communication distance of the experimental RFID tag (B) is approximately <NUM>, and the communication distance of the experimental RFID tag (C) is approximately <NUM>.

Note that items (a) to (c) in <FIG> depict communication distances that are measured in the aircraft tire when the experimental RFID tags (A) to (C) are provided along a circumferential direction of the aircraft tire as a reference.

According to these graphs, in the case of the aircraft tire (<NUM> inches), the communication distance tends to be longer when the experimental RFID tags (A) to (C) are provided along the width direction than when the experimental RFID tags (A) to (C) are provided along the circumferential direction.

By contrast, in the case of the aircraft tire (<NUM> inches), the communication distance tends to be longer when the experimental RFID tags (A) to (C) are provided along the circumferential direction than when the experimental RFID tags (A) to (C) are provided along the width direction.

As described above, when the experimental RFID tags (A) to (C) are attached to the tire inner surface <NUM> such that the extending direction D1 of the antennas A1 and A2 are parallel to the tire width direction D2 or intersect the tire width direction D2 within a predetermined angle range (For example, within <NUM> degrees), the aircraft tire (<NUM> inches) having relatively large diameter has a longer communication distance than the aircraft tire (<NUM> inches) having relatively small diameter.

Referring to <FIG>, a relationship between the communication distance and "L/W" will be described with respect to the aircraft tire T (<NUM> inches) provided with the RFID tag <NUM> and the aircraft tire for a comparative example (<NUM> inches).

<FIG> is a table comparing a value L (antenna width)/W (tire width) of the aircraft tire T (<NUM> inches) according to the present embodiment and the value L (antenna width)/W (tire width) of the aircraft tire (<NUM> inches) according to the comparative example; and <FIG> is a graph depicting a relationship between the value L (antenna width)/W (tire width) and the communication distance in the aircraft tire T (<NUM> inches) and the value L (antenna width)/W (tire width) and the communication distance in the aircraft tire (<NUM> inches) according to the comparative example.

As described in <FIG>, for the aircraft tire with a diameter <NUM> inches (radial) and a tire width <NUM> equipped with an antenna with an antenna width of <NUM>, the value L/W with an antenna width of <NUM> is <NUM> and the communication distance is <NUM>.

For the aircraft tire with a diameter <NUM> inches (radial) and a tire width <NUM> equipped with an antenna with an antenna width of <NUM> the value L/W is <NUM> and the communication distance is <NUM>.

For the aircraft tire with a diameter <NUM> inches (bias) and a tire width <NUM> equipped with an antenna with an antenna width of <NUM> the value L/W is <NUM> and the communication distance is <NUM>.

By contrast, for the aircraft tire with a diameter <NUM> inches and a tire width <NUM> equipped with an antenna with an antenna width of <NUM>, the value L/W is <NUM> and the communication distance is <NUM>.

For the aircraft tire with a diameter <NUM> inches and a tire width <NUM> equipped with an antenna with an antenna width of <NUM>, the L/W is <NUM>, and the communication distance is <NUM>.

<FIG> depicts a graph in which the values described above are plotted with the vertical axis representing the communication distance (cm) and the horizontal axis representing the value L/W.

As can be seen from <FIG>, the aircraft tire T with diameter <NUM> inches according to the present embodiment is superior to the aircraft tire according to the comparative example (<NUM> inch) in terms of the communication distance.

It can also be seen that in the aircraft tire T (<NUM> inches) according to the present embodiment, the value L/W converges to a range of <NUM> to <NUM>.

Accordingly, in the case where the diameter of the aircraft tire is <NUM> inches or more, and where the width size of the aircraft tire is denoted as "W" and the sum of the lengths of the antennas in the extending direction is denoted as "L", a relationship <NUM> < L/W < <NUM> is satisfied.

According to the above-described embodiment, the following effects are obtained.

That is, the aircraft tire T according to the present embodiment includes an RFID tag <NUM> having an IC chip <NUM> configured to store information about the aircraft tire and antennas A1 and A2 extended from the IC chip <NUM>; wherein, in a tread surface view, the antennas A1 and A2 are disposed such that the extending direction D1 of the antennas A1 and A2 are parallel to the tire width direction or intersects the tire width direction D2 within the predetermined angle range, and when the relationship <NUM><L/W <<NUM> is satisfied, where the width dimension of the aircraft tire is denoted as "W" and the total length of the antenna in the extending direction is denoted as "L", and when the diameter of the aircraft tire T is <NUM> inches or more, the communication performance improves.

When the value L/W is smaller than <NUM>, the total antenna length (L) (antenna width) is short with respect to the tire width (W), so that the antenna characteristics may deteriorate.

If L/W is greater than <NUM>, the total antenna length (L) (antenna width) is long with respect to the tire width (W), resulting in a disadvantage that workability and mountability at the time of mounting the antenna may deteriorate.

Since the antenna can be configured of a monopole antenna or a dipole antenna exhibiting a linear shape or wavy line shape, various types of RFID tags can be employed.

Since the RFID tag <NUM> can be attached to the tire inner surface <NUM>, it can be brought close to the bead section <NUM>, and communication property may be further improved by functioning the bead section <NUM> as an antenna. Further, the sensitivity of the RFID tag <NUM> can be enhanced by the reflection of the electromagnetic wave by the bead section <NUM>.

Since the RFID tag <NUM> may be disposed to be circumferentially apart from the balance patch provided on the tire inner surface, the RFID tag <NUM> may be provided in a state where the balance of the aircraft tire T is maintained.

Further, since the belt part <NUM> disposed in the tread section <NUM> is made of a non-metal material, the attenuation of electromagnetic waves or the like between the RFID tag <NUM> and the RFID reader/writer <NUM> may be reduced and the communication performance may be improved.

Claim 1:
An aircraft tire (T) having a pair of bead sections (<NUM>), sidewall sections (<NUM>) extending from outer side in a radial direction of the bead sections, and a tread section (<NUM>) extending between the sidewall sections, the aircraft tire comprising:
an RFID tag (<NUM>) comprising: a tag main body (<NUM>) configured to store information about the aircraft tire, and an antenna (A1, A2, A3, A4a, A4b) extended from the tag main body, wherein
in a tread surface view, the antenna is disposed such that an extending direction (D1) of the antenna is parallel to a tire width direction (D2) or intersects the tire width direction within a predetermined angle range of <NUM> degrees ,
characterized in that
the aircraft tire has a diameter that is <NUM> inches or more, and
the aircraft tire satisfies a configuration <NUM>< L/W <<NUM>, where a width (W) of the aircraft tire is denoted as "W" and a total length of the antenna in the extending direction of the antenna is denoted as "L".