Patent Application
20220410640
The present technology relates to a pneumatic tire embedded with a transponder, and relates particularly to a pneumatic tire that enables steering stability and durability of the tire to be improved while ensuring communication performance of the transponder.
For a pneumatic tire, embedment of an RFID (radio frequency identification) tag (transponder) in the tire has been proposed (see, for example, Japan Unexamined Patent Publication No. H07-137510)). In a case where a transponder is embedded in a tire, there is a problem in that, for example, the transponder disposed between a carcass layer and a bead filler disturbs a carcass line in the carcass layer, degrading steering stability of the tire. Additionally, depending on the end position of a turned up portion of the carcass layer, the distance between the transponder and the end of the turned up portion of the carcass layer may be extremely small, and the tire may be damaged such that the damage originates from the transponder. Furthermore, in a case where 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.
The present technology provides a pneumatic tire that enables steering stability and durability of the tire to be improved while ensuring communication performance of a transponder.
A pneumatic tire according to an embodiment of the present technology 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 the carcass layer being turned up from a tire inner side to a tire outer side around the bead core, a transponder being embedded between the carcass layer and a rubber layer disposed in the sid ewall portion on an outer side of the carcass layer, the transponder extending along the tire circumferential direction in contact with the rubber layer, and the transponder being disposed 10 mm or more away from an end of the turned up portion of the carcass layer in the tire radial direction.
In an embodiment of the present technology, in the pneumatic tire in which the carcass layer is turned up from the tire inner side to the tire outer side around the bead core of each bead portion, the transponderis embedded between the carcass layer and the rubber layer disposed in the sidewall portion on the outer side of the carcass layer, the transponder extending along the tire circumferential direction in contact with the rubber layer, and the transponder is disposed 10 mm or more away from an end of the turned up portion of the carcass layer in the tire radial direction. Thus, the arrangement of the transponder allows steering stability of the tire to be improved without disturbing the carcass line. Additionally, metal interference is unlikely to occur, and the communication performance of the transponder can be ensured. An extremely short distance between the transponder and the end of the turned up portion of the carcass layer may cause stress concentration, degrading the durability of the tire. However, ensuring the distance described above allows the durability of the tire to be improved.
In the pneumatic tire according to an embodiment of the present technology, preferably, the end of the turned up portion of the carcass layer located in the sidewall portion on an outermost side in a tire width direction is disposed between a position located on an outer side of and 5 mm away from an upper end of the bead filler in the tire radial direction and a position located on an inner side of and 15 mm away from an end of the belt layer in the tire radial direction, and the transponder is disposed on an outer side of and 15 mm or more away from an upper end of the bead core in the tire radial direction. The end of the turned up portion of the carcass layer located in the sidewall portion on the outermost side in the tire width direction is located in the region described above, thus allowing the durability of the tire to be effectively improved. In addition, the transponder is disposed on the outer side of and 15 mm or more away from the upper end of the bead core in the tire radial direction, thus making metal interference unlikely to occur to allow the communication performance of the transponder to be sufficiently ensured.
Preferably, a 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 a cross-sectional center of the transponder and a tire outer surface is 2 mm or more. Accordingly, tire durability can be effectively improved, and tire scratch resistance can be improved.
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 outer surface uneven.
Preferably, the transponder includes an IC (integrated circuit) 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 technology 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, 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 disposed between the carcass layer 4 and the rubber layer 10 in contact with the rubber layer 10. In other words, the transponder 20 is disposed between the carcass layer 4 and the sidewall rubber layer 12 or the rim cushion rubber layer 13 as an arrangement region in the tire width direction such that the transponder 20 contacts the rubber layer. Additionally, the transponder 20 is disposed 10 mm or more away from an end 4e of a turned up portion 4B of the carcass layer 4 in the tire radial direction as an arrangement region thereof in the tire radial direction. Additionally, the transponder 20 extends in the tire circumferential direction. The transponder 20 may be disposed inclined at an angle ranging from −10° to 10° with respect to the tire circumferential direction.
Note that in the embodiment of
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 is embedded between the carcass layer 4 and the rubber layer 10 disposed in the sidewall portion 2 on the outer side of the carcass layer 4, the transponder 20 extending along the tire circumferential direction in contact with the rubber layer 10, and the transponder 20 is disposed 10 mm or more away from the end 4e of the turned up portion 4B of the carcass layer 4 in the tire radial direction. Thus, the arrangement of the transponder 20 does not disturb a carcass line, allowing the steerinu stability of the tire to be improved. Additionally, metal interference is unlikely to occur, and the communication performance of the transpon der 20 can be ensured. An extremely short distance between the transponder 20 and the end 4e of the turned up portion 4B of the carcass layer 4 may cause stress concentration, degrading the durability of the tire. However, ensuring the distance described above allows the durability of the tire to be improved.
In the pneumatic tire described above, the end 4e of the turned up portion 4B of the carcass layer 4 located in the sidewall portion 2 on the outermost side in the tire width direction is disposed at a position P1 located on the outer side of and 5 mm away from an upper end 6e of the head filler 6 in the tire radial direction and a position P2 located on the inner side of and 15 mm away from an end 7e of the belt layer 7 in the tire radial direction, and the transponder 20 may be disposed on the outer side of and 15 mm or more away from an upper end 5e of the bead core 5 in the tire radial direction. In other words, the end 4e of the turned up portion 4B of the carcass layer 4 is disposed in a region S1 illustrated in
In the pneumatic tire described above, in a case where the end 4e of the turned up portion 4B of the carcass layer 4 located in the sidewall portion 2 on the outermost side in the tire width direction is disposed in the region ST, the durability of the tire can be effectively improved. Additionally, in a case where the transponder 20 is disposed further on the outer side than the position P3 in the tire radial direction, metal interference is unlikely to occur, and the communication performance of the transponder can be sufficiently ensured. In this regard, in a case where the transponder 20 is disposed further on the inner side than the position P3 in the tire radial direction, metal interference with a rim flange occurs, leading to the tendency to degrade the communication performance of the transponder 20. On the other hand, in a case where the end 4e of the turned up portion 4B of the carcass layer 4 is disposed further on the inner side than the position P1 in the tire radial direction or on the outer side than the position P2 in the tire radial direction, the durability of the tire tends to be degraded.
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 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 (relative humidity) in accordance with the standard conditions of the JIS (Japanese industrial Standard) 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 (ultra-high frequency) hand, 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 outer surface as illustrated in
As illustrated in
Tires according to Comparative Examples 1 to 5 and Examples 1 to 18 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 bead 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 the carcass layer being turned up from the tire inner side to the tire outer side around the bead core, 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 end position of the turned up portion, the distance between the transponder and the tire outer surface, the relative dielectric constant of a 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 bead filler and the carcass 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. The position of the transponder (tire radial direction) indicates the distance (mm) measured from the end of the turned up portion of the carcass layer in the tire radial direction The position of the transponder (tire circumferential direction) indicates the distance (mm) measured from the center of the transponder to the splice portion of the tire component in the tire circumferential direction. In addition, in Tables 1 and 2. the end position of the turned up portion corresponds to each of the positions A to E illustrated in
Tire evaluation (steering stability, durability, scratch resistance, and appearance) and transponder evaluation (communication performance and. durability) were conducted on the test tires using a test method described below, and the results are indicated in Tables 1 and 2.
Steering Stability (Tire):
Each test tire was assembled on a wheel of a standard rim and mounted on a test vehicle, and sensory evaluation by a test driver was conducted on a test course. The evaluation results are expressed as three levels: “Excellent” indicates that the result is very good, “Good” indicates that the result is good, and “Fair” indicates that the result is slightly inferior.
Durability (Tire and Transponder):
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.
Scratch Resistance (Tire):
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 while being in contact with a curb of 100 mm in height. After traveling, the presence of damage to the tire outer surface was visually checked. Evaluation resul ts indicate the presence of damage to the tire outer surface.
Appearance (Tire):
For each test tire, the portion of the tire outer surface corresponding to the arrangement section for the transponder was visually checked. in the evaluation results, “Good” indicates that the tire outer surface had no unevenness caused by the arrangement of the transponder, and “Poor” indicates that the tire outer surface had unevenness.
Communication Performance (Transponder):
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 expressed as three levels: “Excellent” indicates that the communication distance is 500 mm or more. “Good” indicates that the communication distance is 150 mm or more and less than 500 mm, and “Fair” indicates that the communication distance is less than 150 mm.
As can be seen from Tables l and 2, in the pneumatic tires of Examples 1 to 18, the steering stability and durability of the tire and the communication performance of the transponder were improved in a well-balanced manner. In the pneumatic tire of Example 9, the distance between the transponder and the tire outer surface was set to a small value, thus reducing the scratch resistance of the tire. In the pneumatic tire of Example 17, the thickness of the coating layer coverinu the transponders was set to a large value, thus degrading the appearance of the tire. The pneumatic tire of Example 18 included a pillar-shaped transponder, and thus the durability of the transponder was improved, and no failure originating from the transponder occurred.
On the other hand, in Comparative Example 1, the transponder was disposed between the bead filler and the carcass layer, thus degrading the steering stability of the tire. In Comparative Examples 1 to 3, the transponder was disposed at a height identical to that of the end position of the turned up portion of the carcass layer, thus degrading the durability of the tire. In Comparative Example 4, the separation distance between the transponder and the end position of the turned up portion of the carcass layer was not sufficiently ensured, thus degrading the durability of the tire. In Comparative Example 5, the separation distance between the transponder and the end position of the turned up portion of the carcass layer was ensured, but the transponder was disposed between the head filler and the carcass layer, thus degrading the steering stability of the tire.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-214373 | Nov 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/043765 | 11/25/2020 | WO |
