Patent Application
20230001750
The present invention relates to a pneumatic tire embedded with a transponder, and relates particularly to a pneumatic tire that enables communication performance and scratch resistance of the transponder to he improved.
For a pneumatic tire, embedment of an RFD tag (transponder) in the tire has been proposed (see, for example, Patent Document 1). In a case where a transponder is embedded in a tire, for example, when the transponder is disposed near a metal tire component (e.g., a bead core or the like), there is a problem in that the tire component and the transponder interfere with each other, degrading the communication performance of the transponder. Additionally, in a case where the transponder is disposed on an outer side of a turned up portion of a carcass layer in a tire width direction, the transponder may be damaged due to damage to a sidewall portion.
Patent Document 1: JPH7-137510 A
An object of the present invention is to provide a pneumatic tire that enables communication performance and scratch resistance of a transponder to be improved.
A pneumatic tire according to an embodiment of the present invention that achieves the object described above includes a tread portion extending in a tire circumferential direction and having an annular shape, a pair of sidewall portions respectively disposed on both sides of the tread portion, and a pair of bead portions each disposed on an inner side of the sidewall portions in a tire radial direction, a bead filler being disposed on an outer circumference of a bead core of each bead portion, at least one carcass layer being mounted between the pair of bead portions, a plurality of belt layers being disposed on an outer circumferential side of the carcass layer in the tread portion, and an innerliner layer being disposed in a tire inner surface along the carcass layer, a transponder that extends along the tire circumferential direction being embedded between the carcass layer and the innerliner layer, and the transponder being disposed between a position located on an outer side of and 15 mm away from an upper end of the bead core in the tire radial direction and a position located on an inner side of and 5 mm away from an end of the belt layer in the tire radial direction.
In an embodiment of the present invention, the transponder extending along the tire circumferential direction is embedded between the carcass layer and the innerliner layer, and the transponder is disposed between the position located on the outer side of and 15 mm away from the upper end of the bead core in the tire radial direction and the position located on the inner side of and 5 mm away from the end of the belt layer in the tire radial direction. This makes metal interference less likely to occur, allowing the communication performance of the transponder to be ensured. Additionally, the transponder can be prevented from being damaged due to damage to the sidewall portion.
In the pneumatic tire according to an embodiment of the present invention, preferably, the transponder is disposed between a position located on the outer side of and 5 mm away from the upper end of the bead filler in the tire radial direction and a position located on the inner side of and 5 mm away from the end of the belt layer in the tire radial direction. Accordingly, the transponder is disposed in a flex zone with a small rubber gauge. However, this region is subjected to less attenuation of radio waves during communication of the transponder, allowing the communication performance of the transponder to be effectively improved. Accordingly, the transponder can be prevented from being damaged due to damage to the innerliner layer while the tire is mounted on a rim.
Preferably, the center of the transponder is disposed 10 mm or more away from a splice portion of a tire component in the tire circumferential direction. Accordingly, tire durability can be effectively improved.
Preferably, a distance between the cross-sectional center of the transponder and the tire inner surface is 1 mm or more. Accordingly, tire durability can be effectively improved, and the transponder can be prevented from being damaged due to damage to the innerliner layer while the tire is mounted on a rim.
Preferably, the transponder is covered with a coating layer, and the coating layer has a relative dielectric constant of 7 or less. Accordingly, the transponder is protected by the coating layer, allowing the durability of the transponder to be improved and also ensuring radio wave transmissivity of the transponder to allow the communication performance of the transponder to be effectively improved.
Preferably, the transponder is covered with a coating layer, and the coating layer has a thickness of from 0.5 mm to 3.0 mm. Accordingly, the communication performance of the transponder can be effectively improved without making the tire inner surface uneven.
Preferably, the transponder includes an IC substrate storing data and an antenna transmitting and. receiving data, and the antenna has a helical shape. Accordingly, it can conform deformation of the tire during traveling, allowing the durability of the transponder to be improved.
Configurations of embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As illustrated in
At least one carcass layer 4 (one layer in
On the other hand, a plurality of belt layers 7 (two layers in
To improve high-speed durability, at least one belt cover layer 8 (two layers in
In the pneumatic tire described above, both ends 4e of the carcass layer 4 are folded back from the tire inner side to the tire outer side around the bead cores 5, and are disposed wrapping around the bead cores 5 and the bead fillers 6. The carcass layer 4 includes: a body portion 4A corresponding to a portion extending from the tread portion 1 through each of the sidewall portions 2 to each of the bead portions 3; and a turned-up portion 4B corresponding to a portion turned up around the bead core 5 at each of the bead portions 3 and extending toward each sidewall portion 2 side.
Additionally, on a tire inner surface, an innerliner layer 9 is disposed along the carcass layer 4. Furthermore, a cap tread rubber layer 11 is disposed in the tread portion 1, a sidewall rubber layer 12 is disposed in the sidewall portion 2, and a rim cushion rubber layer 13 is disposed in the bead portion 3. A rubber layer 10 disposed on the outer side of the carcass layer 4 in the sidewall portion 2 includes the sidewall rubber layer 12 and the rim cushion rubber layer 13.
Additionally, in the pneumatic tire described above, a transponder 20 is embedded between the carcass layer 4 and the innerliner layer 9. Additionally, in an arrangement region for the transponder 20 in the tire radial direction, the transponder 20 is disposed between a position P1 located on the outer side of and 15 mm away from an upper end 5e of the bead core 5 in the tire radial direction (the end portion on the outer side in the tire radial direction) and a position P2 located on the inner side of and 5 mm away from an end 7e of the belt layer 7 in the tire radial direction In other words, the transponder 20 is disposed in a region S1 illustrated in
As the transponder 20, for example, a radio frequency identification (RFID) tag can be used. As illustrated in
The overall shape of the transponder 20 is not particularly limited, and for example, a pillar- or plate-like shape can be used as illustrated in
In the pneumatic tire described above, the transponder 20 extending along the tire circumferential direction is embedded between the carcass layer 4 and the innerliner layer 9, and the transponder 20 is disposed between the position P1 located on the outer side of and 15 mm away from the upper end 5e of the bead core 5 in the tire radial direction and the position P2 located on the inner side of and 5 mm away from the end 7e of the belt layer 7 in the tire radial direction, thus making metal interference less likely to occur to allow the communication performance of the transponder 20 to be ensured. Additionally, the transponder 20 can be prevented from being damaged due to damage to the sidewall portion 2.
In this regard, in a case where the transponder 20 is disposed further on the inner side than the position P1 in the tire radial direction, metal interference with the rim flange occurs, leading to the tendency to degrade the communication performance of the transponder20. Additionally, in a case where the transponder20 is disposed further on the outer side than the position P2 in the tire radial direction, metal interference with the belt layer 7 occurs, leading to the tendency to degrade the communication performance of the transponder 20.
In the pneumatic tire described above, the transponder 20 may be disposed between a position P3 located on the outer side of and 5 mm away from an upper end 6e of the bead filler 6 in the tire radial direction and the position P2 located on the inner side of and 5 mm away from the end 7e of the belt layer 7 in the tire radial direction. In other words, the transponder 20 may be disposed in a region S2 illustrated in
As illustrated in
Note that in the embodiment of
As illustrated in
Additionally, the transponder 20 may be covered with a coating layer 23. The coating layer 23 coats the entire transponder 20 while holding both front and rear sides of the transponder 20. The coating layer 23 may be formed from rubber having physical properties identical to those of the rubber constituting a tire component such as the sidewall rubber layer 12 or the rim cushion rubber layer 13 or from rubber having different physical properties. The transponder 20 is protected by the coating layer 23 as described above, and thus the durability of the transponder 20 can be improved.
In the pneumatic tire described above, with the transponder 20 covered with the coating layer 23, the coating layer 23 preferably has a relative dielectric constant of 7 or less and more preferably from 2 to 5. By properly setting the relative dielectric constant of the coating layer 23 as described above, radio wave transmissivity can be ensured during emission of a radio wave by the transponder 20, effectively improving the communication performance of the transponder 20. Note that the rubber constituting the coating layer 23 has a relative dielectric constant of from 860 MHz to 960 MHz at ambient temperature. In this regard, the ambient temperature is 23±2° C and 60%±5% RH in accordance with the standard conditions of the JIS standard. The relative dielectric constant of the rubber is measured after 24 hour treatment at 23° C and 60% RH. The range from 860 MHz to 960 MHz described above corresponds to the allocated frequency of the RFID in the current UHF band, but in a case where the allocated frequency is changed, the relative dielectric constant in the range of the allocated frequency may be specified as described above.
In addition, with the transponder 20 covered with the coating layer 23, a thickness t of the coating layer 23 preferably ranges from 0.5 mm to 3.0 mm, and more preferably ranges from 1.0 mm to 2.5 mm. In this regard, the thickness t of the coating layer 23 is the thickness of the rubber at a position where the rubber includes the transponder 20, and is, for example, a rubber thickness obtained by summing a thickness t1 and a thickness t2 on a straight line extending through the center of the transponder 20 and orthogonally to the tire inner surface as illustrated in
In the embodiment described above, an example of a pneumatic tire including a single carcass layer is illustrated. However, no such limitation is intended, and the pneumatic tire may include two carcass layers. Additionally, in the embodiment described above, an example has been illustrated in which the end 4e of the turned-up portion 4B of the carcass layer 4 is disposed beyond the upper end 6e of the bead filler 6 and halfway up the sidewall portion 2. However, no such limitation is intended, and the end 4e can be disposed at any height.
Tires according to Comparative Examples 1 to 4 and Examples 1 to 14 were manufactured. The tires have a tire size of 265/40ZR20 and include a tread portion extending in the tire circumferential direction and having an annular shape, a pair of sidewall portions respectively disposed on both sides of the tread portion, and a pair of bead portions each disposed on an inner side of the sidewall portions in the tire radial direction, a head filler being disposed on an outer circumference of a bead core of each bead portion, a carcass layer being mounted between the pair of bead portions, a plurality of belt layers being disposed on an outer circumferential side of the carcass layer in the tread portion, and an innerliner layer being disposed in a tire inner surface along the carcass layer, in which a transponder extending along the tire circumferential direction is embedded and in which the position of the transponder (tire width direction, tire radial direction, and tire circumferential direction), the distance between the transponder and the tire inner surface, the relative dielectric constant of the coating layer, the thickness of the coating layer, and the form of the transponder are set as indicated in Tables 1 and 2.
Note that in Tables 1 and 2, the position “X” of the transponder (tire width direction) indicates that the transponder is disposed between the carcass layer and the innerliner layer, the position “Y” of the transponder (tire width direction) indicates that the transponder is disposed between the carcass layer and the sidewall rubber layer in contact with the sidewall rubber layer, and the position “Z” of the transponder (tire width direction) indicates that the transponder is disposed between the carcass layer and the rim cushion rubber layer and in contact with the rim cushion rubber layer. Additionally, in Tables 1 and 2, the position of the transponder (tire radial direction) corresponds to each of the positions A to E illustrated in
Tire evaluation (durability) and transponder evaluation (communication performance, durability, scratch resistance, and damage resistance) were conducted on the test tires using a test method described below, and the results are indicated in Tables 1 and 2.
Each of the test tires was mounted on a wheel of a standard rim, and a traveling test was performed by using a drum testing machine at an air pressure of 120 kPa, 102% of the maximum load, and a traveling speed of 81 km/h. After the test was performed, the traveling distance at the time of occurrence of a failure in the tire was measured. Evaluation results are expressed as four levels: “Excellent” indicates that the traveling distance reached 6480 km, “Good” indicates that the traveling distance was 4050 km or more and less than 6480 km, “Fair” indicates that the traveling distance was 3240 km or more and less than 4050 km, and “Poor” indicates that the traveling distance was less than 3240 km. Furthermore, after traveling was ended, the tire outer surface of each test tire was visually checked, and whether the tire failure originated from the transponder was checked. Evaluation results indicate the presence of the failure.
For each test tire, a communication operation with the transponder was performed using a reader/writer. Specifically, the maximum communication distance was measured with the reader-writer set at a power output of 250 mW and a carrier frequency of from 860 MHz to 960 MHz. The evaluation results are indicated using three stages. The result is indicated as “Excellent” when the communication distance is 500 mm or more, indicated as “Good” when the communication distance is 150 mm or more and less than 500 mm, and indicated as “Fair” when the communication distance is less than 150 mm.
Each test tire was assembled on a wheel of a standard rim and mounted on a test vehicle, and a traveling test was conducted in which the vehicle traveled at an air pressure of 230 kPa and a traveling speed of 20 km/h and ran onto a curb of 100 mm in height. After traveling, the portion of the tire outer surface corresponding to the arrangement section for the transponder was visually checked. The evaluation results indicate the presence of damage to the tire outer surface caused by the arrangement of the transponder.
For each test tire, the portion of the tire inner surface corresponding to the arrangement section for the transponder was visually checked when the rim was replaced. The evaluation results indicate the presence of damage to the transponder caused by damage to the innerliner.
As can be seen from Table 1 and Table 2, in the pneumatic tires of Examples 1 to 14, the communication performance and scratch resistance of the transponder were improved in a well-balanced manner. In the pneumatic tire of Example 6, a large value was set for the distance between the transponder and the tire inner surface, leading to improved damage resistance of the transponder. In the pneumatic tire of Example 13, a large thickness was set for the coating layer covering the transponders, thus making the tire inner surface uneven. The pneumatic tire of Example 14 included a pillar-shaped transponder, thus improving the durability of the transponder. Accordingly, no failure originated from the transponder.
In Comparative Examples 1 to 4, the position of the transponder in the tire radial direction was set lower than the region specified in an embodiment of the present invention, thus degrading the communication performance of the transponder. In Comparative Examples 1 and 2, the transponder was disposed between the carcass layer and the sidewall rubber layer or the rim cushion rubber layer in contact with the rubber layer, thus degrading the scratch resistance of the transponder. In Comparative Example 4, the position of the transponder in the tire radial direction was set higher than the region specified in an embodiment of the present invention, thus degrading the communication performance of the transponder.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-214374 | Nov 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/043766 | 11/25/2020 | WO |
