Pneumatic tire

Abstract

To provide a pneumatic tire that can improve durability of a transponder while securing durability of a tire.SOLUTION: A pneumatic tire includes: a tread part 1 extending in a tire circumferential direction and formed into an annular shape; a pair of side wall parts 2 disposed on both sides of the tread part 1; and a pair of bead parts 3 disposed on a tire radial inside of the side wall parts 2. A transponder 20 is embedded in the tire. The transponder 20 is coated by a coating layer 23. The coating layer 23 has a cleavage elasticity modulus at the time of 10% deformation at 20°C which is controlled within a range of 0.5 to 5.0 MPa.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a pneumatic tire in which a transponder covered with a coating layer is embedded, and more particularly to a pneumatic tire that enables improvement of the durability of the transponder while ensuring the durability of the tire.

Background Art

[0002] In pneumatic tires, it has been proposed to embed an RFID tag (transponder) in the tire (see, for example, Patent Document 1). When embedding a transponder in a tire, if the physical properties of the coating layer for protecting the transponder are inappropriate, it is not possible to sufficiently ensure the durability of the tire or the transponder. That is, if the elastic modulus of the coating layer is too low, the protective effect of the transponder is impaired, and if the elastic modulus of the coating layer is too high, stress concentration occurs near the edge of the coating layer, leading to tire damage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a pneumatic tire that enables improvement of the durability of the transponder while ensuring the durability of the tire.

Means for Solving the Problems

[0005] In order to achieve the above object, the pneumatic tire of the present invention includes a tread portion that extends in the tire circumferential direction and forms an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of these sidewall portions. In the pneumatic tire, a transponder is embedded in the tire, the transponder is covered by a covering layer, and the secant modulus of elasticity at 20°C when the covering layer is deformed by 10% is in the range of 0.5 MPa to 5.0 MPa. , the storage elastic modulus E'c(20°C) of the coating layer is in the range of 2 MPa to 12 MPa, the transponder is embedded outside the tire width direction from the carcass layer, and the storage elastic modulus E'c(20°C) of the coating layer and the storage elastic modulus E'out(20°C) at 20°C of the rubber member having the largest storage elastic modulus at 20°C among the rubber members located outside the tire width direction from the transponder satisfy the relationship of 0.1 ≦ E'c(20°C) / E'out(20°C) ≦ 1.5, the center of the transponder is arranged at a distance of 10 mm or more in the tire circumferential direction from the splice portion of the tire constituent member It is characterized by this.

Effects of the Invention

[0006] In the present invention, since the transponder is covered by the covering layer and the secant modulus of elasticity at 20°C when the covering layer is deformed by 10% is set within the above range, it is possible to sufficiently exhibit the protective effect of the covering layer on the transponder while avoiding stress concentration near the edge of the covering layer. Thereby, while ensuring the durability of the tire, the durability of the transponder can be improved.

[0007] In the pneumatic tire of the present invention, it is preferable that the relative permittivity of the covering layer is 7 or less. Thereby, the radio wave transmissivity of the transponder can be ensured and the communication performance of the transponder can be improved.

[0008] It is preferable that the storage modulus of elasticity E'c(20°C) of the covering layer at 20°C is in the range of 2 MPa to 12 MPa. Thereby, while ensuring the durability of the tire, the durability of the transponder can be effectively improved.

[0009] The transponder is embedded outside the tire width direction from the carcass layer, and the storage elastic modulus E'c(20°C) of the coating layer and the storage elastic modulus E'out(20°C) at 20°C of the rubber member with the largest storage elastic modulus among the rubber members located outside the tire width direction from the transponder satisfy the relationship of 0.1 ≦ E'c(20°C) / E'out(20°C) ≦ 1.5. This can effectively improve the durability of the transponder while ensuring the durability of the tire.

[0010] The coating layer preferably consists of rubber or elastomer and 20 phr or more of a white filler. This can make the relative dielectric constant of the coating layer relatively low and effectively improve the communication performance of the transponder.

[0011] The white filler preferably contains 20 phr to 55 phr of calcium carbonate. This can make the relative dielectric constant of the coating layer relatively low and effectively improve the communication performance of the transponder.

[0012] The center of the transponder is preferably arranged at a distance of 10 mm or more in the tire circumferential direction from the splice part of the tire component. This can effectively improve the durability of the tire.

[0013] The transponder is preferably arranged between the position 15 mm radially outside the tire from the upper end of the bead core of the bead part and the maximum tire width position. Since the transponder is arranged in a region where the stress amplitude during running is small, the durability of the transponder can be effectively improved, and furthermore, the durability of the tire will not be reduced.

[0014] The distance between the cross-sectional center of the transponder and the tire surface is preferably 1 mm or more. This can effectively improve the durability of the tire and also improve the puncture resistance of the tire.

[0015] The thickness of the coating layer is preferably 0.5 mm to 3.0 mm. Thereby, the communication performance of the transponder can be effectively improved without causing unevenness on the tire surface.

[0016] The transponder has an IC substrate for storing data and an antenna for transmitting and receiving data, and the antenna is preferably spiral. Thereby, it can follow the deformation of the tire during running, and the durability of the transponder can be improved.

[0017] In the present invention, the secant modulus at 10% deformation is calculated based on the stress-strain curve measured under the conditions of a specified temperature and a tensile speed of 500 mm / min using a dumbbell-shaped test piece of No. 3 type in accordance with JIS-K6251. However, when a dumbbell-shaped test piece of No. 3 type cannot be taken from the tire, a test piece having a different shape may be used. Further, the storage modulus E' is measured using a viscoelastic spectrometer in accordance with JIS-K6394 under the conditions of each specified temperature, a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain of ±2% in the tensile deformation mode.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0019] Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1 to 4 show a pneumatic tire according to an embodiment of the present invention.

[0020] As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 extending in the tire circumferential direction and forming an annular shape, a pair of sidewall portions 2 disposed on both sides of the tread portion 1, and a pair of bead portions 3 disposed on the radially inner side of these sidewall portions 2 in the tire diameter direction.

[0021] Between the pair of bead portions 3, at least one layer (one layer in FIG. 1) of carcass layer 4 formed by arranging a plurality of carcass cords in the radial direction is mounted. The carcass layer 4 is covered with rubber. As the carcass cords constituting the carcass layer 4, organic fiber cords such as nylon and polyester are preferably used. An annular bead core 5 is embedded in each bead portion 3, and a bead filler 6 made of a rubber composition having a triangular cross section is disposed on the outer circumference of the bead core 5.

[0022] On the other hand, on the outer peripheral side of the tire of the carcass layer 4 in the tread portion 1, a plurality of layers (two layers in FIG. 1) of belt layers 7 are embedded. The belt layer 7 includes a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to cross each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set in the range of, for example, 10° to 40°. As the reinforcing cords of the belt layer 7, steel cords are preferably used.

[0023] On the outer peripheral side of the tire of the belt layer 7, at least one layer (two layers in FIG. 1) of belt cover layer 8 formed by arranging reinforcing cords at an angle of, for example, 5° or less with respect to the tire circumferential direction is arranged for the purpose of improving high-speed durability. In FIG. 1, the belt cover layer 8 located on the inner side in the tire radial direction constitutes a full cover that covers the entire width of the belt layer 7, and the belt cover layer 8 located on the outer side in the tire radial direction constitutes an edge cover layer that covers only the end portion of the belt layer 7. As the reinforcing cords of the belt cover layer 8, organic fiber cords such as nylon and aramid are preferably used.

[0024] In the pneumatic tire, both end portions 4e of the carcass layer 4 are folded from the inner side to the outer side around each bead core 5 and are arranged so as to wrap the bead core 5 and the bead filler 6. The carcass layer 4 includes a main body portion 4A which is a portion extending from the tread portion 1 through each sidewall portion 2 to each bead portion 3, and a winding-up portion 4B which is a portion wound around the bead core 5 in each bead portion 3 and extends toward each sidewall portion 2 side.

[0025] Also, an inner liner layer 9 is arranged along the carcass layer 4 on the inner surface of the tire. A cap tread rubber layer 11 is arranged in the tread portion 1, a sidewall rubber layer 12 is arranged in the sidewall portion 2, and a rim cushion rubber layer 13 is arranged in the bead portion 3.

[0026] Also, in the pneumatic tire, a transponder 20 is embedded in a portion outside the carcass layer 4 in the tire width direction. The transponder 20 extends along the tire circumferential direction. The transponder 20 may be arranged to be inclined in the range of -10° to 10° with respect to the tire circumferential direction. Also, as shown in FIG. 4, the transponder 20 is covered by a covering layer 23. This covering layer 23 covers the entire transponder 20 so as to sandwich both the front and back surfaces of the transponder 20. The covering layer 23 may be formed of rubber having the same physical properties as the rubber constituting the sidewall rubber layer 12 or the rim cushion rubber layer 13, or may be formed of rubber having different physical properties.

[0027] As the transponder 20, for example, an RFID (Radio Frequency Identification) tag can be used. As shown in FIGS. 5(a) and 5(b), the transponder 20 has an IC substrate 21 for storing data and an antenna 22 for transmitting and receiving data in a non-contact manner. By using such a transponder 20, information regarding the tire can be written or read out in a timely manner, and the tire can be efficiently managed. Note that RFID is an automatic identification technology composed of a reader / writer having an antenna and a controller, and an ID tag having an IC substrate and an antenna, and capable of communicating data by a wireless method.

[0028] The overall shape of the transponder 20 is not particularly limited, and for example, as shown in FIGS. 5(a) and 5(b), a columnar or plate-like one can be used. In particular, when the columnar transponder 20 shown in FIG. 5(a) is used, it is suitable because it can follow the deformation of the tire in each direction. In this case, the antenna 22 of the transponder 20 protrudes from each of both ends of the IC substrate 21 and has a spiral shape. Thereby, it can follow the deformation of the tire during running, and the durability of the transponder 20 can be improved. Also, by appropriately changing the length of the antenna 22, communication performance can be ensured.

[0029] In the pneumatic tire configured as described above, the secant modulus of elasticity at 20°C at 10% deformation of the coating layer 23 covering the transponder 20 is set in the range of 0.5 MPa to 5.0 MPa. In particular, it is preferable that the secant modulus of elasticity at 20°C at 10% deformation of the coating layer 23 is in the range of 2.0 MPa to 4.0 MPa.

[0030] In the pneumatic tire described above, the transponder 20 is covered by the covering layer 23, and the secant modulus of elasticity at 20°C when the covering layer 23 is deformed by 10% is set within the above range. Therefore, while avoiding stress concentration near the edge of the covering layer 23, it is possible to sufficiently exert the protective effect of the covering layer 23 on the transponder 20. Thereby, while ensuring the durability of the tire, the durability of the transponder 20 can be improved.

[0031] Here, if the secant modulus of elasticity at 20°C when the covering layer 23 is deformed by 10% is lower than the lower limit value, the covering layer 23 is excessively soft. Therefore, as the tire deforms, the covering layer 23 is compressed, and the transponder 20 is likely to be damaged. Conversely, if the secant modulus of elasticity at 20°C when the covering layer 23 is deformed by 10% is higher than the upper limit value, stress concentration occurs near the edge of the covering layer 23 when the tire deforms, and peeling is likely to occur at the interface between the covering layer 23 and the rubber member adjacent to the covering layer 23.

[0032] Furthermore, in the pneumatic tire described above, since the transponder 20 is embedded outside the carcass layer 4 in the tire width direction, there is no tire component that blocks radio waves during communication of the transponder 20, and the communication performance of the transponder 20 can be ensured well. When the transponder 20 is embedded outside the carcass layer 4 in the tire width direction, the transponder 20 can be disposed between the turned-up portion 4B of the carcass layer 4 and the rim cushion rubber layer 13 or between the carcass layer 4 and the sidewall rubber layer 12. As another structure, it is also possible to dispose the transponder 20 between the turned-up portion 4B of the carcass layer 4 and the bead filler 6 or between the main body portion 4A of the carcass layer 4 and the bead filler 6.

[0033] In the pneumatic tire described above, it is preferable that the storage modulus of elasticity E'c(20°C) of the covering layer 23 at 20°C is in the range of 2 MPa to 12 MPa. By setting the physical properties of the covering layer 23 in this way, the durability of the transponder 20 can be effectively improved.

[0034] Here, if the storage elastic modulus E'c(20°C) of the coating layer 23 at 20°C is lower than the lower limit value, the rigidity of the coating layer 23 becomes low and the protective property deteriorates. Conversely, if the storage elastic modulus E'c(20°C) of the coating layer 23 at 20°C is higher than the upper limit value, the rigidity of the coating layer 23 becomes high, the coating layer 23 becomes brittle, and the coating layer 23 is likely to break, so the transponder 20 is likely to be damaged.

[0035] It is preferable that the storage elastic modulus E'c(20°C) of the coating layer 23 at 20°C and the storage elastic modulus E'c(60°C) of the coating layer 23 at 60°C satisfy the relationship of 1.0 ≦ E'c(20°C) / E'c(60°C) ≦ 1.5. By setting the physical properties of the coating layer 23 in this way, the temperature dependence of the coating layer 23 is reduced (it becomes difficult for the coating layer 23 to generate heat), so even if the temperature of the tire rises during high-speed driving, the coating layer 23 does not soften, and the durability of the transponder 20 can be effectively improved.

[0036] In the pneumatic tire described above, among the rubber members (sidewall rubber layer 12 and rim cushion rubber layer 13 in FIG. 1) located outside the tire width direction from the transponder 20, the rubber member with the largest storage elastic modulus E'out(20°C) at 20°C (hereinafter, may also be referred to as an external member) corresponds to the rim cushion rubber layer 13. Note that the coating layer 23 that covers the transponder 20 is not included as the rubber member (external member) with the largest storage elastic modulus at 20°C.

[0037] And in the structure where the transponder 20 is embedded outside the carcass layer 4 in the tire width direction, it is preferable that the storage elastic modulus E'out(20°C) of the external member at 20°C and the storage elastic modulus E'c(20°C) of the coating layer 23 at 20°C satisfy the relationship of 0.1 ≦ E'c(20°C) / E'out(20°C) ≦ 1.5. In particular, it is preferable that the relationship of 0.15 ≦ E'c(20°C) / E'out(20°C) ≦ 1.30 is satisfied. Thereby, while ensuring the durability of the tire, the durability of the transponder 20 can be effectively improved.

[0038] Here, if the value of E'c(20°C) / E'out(20°C) is less than the lower limit value, the rigidity of the coating layer 23 becomes low and the protective property deteriorates. Conversely, if the value of E'c(20°C) / E'out(20°C) is greater than the upper limit value, the rigidity of the coating layer 23 becomes high, the coating layer 23 becomes brittle, and the coating layer 23 is likely to break, so the transponder 20 is likely to be damaged.

[0039] As the composition of the coating layer 23, the coating layer 23 preferably consists of rubber or elastomer and 20 phr or more of a white filler. By configuring the coating layer 23 in this way, the relative permittivity of the coating layer 23 can be made relatively low compared to the case where carbon is contained, and the communication performance of the transponder 20 can be effectively improved. In this specification, "phr" means parts by weight per 100 parts by weight of the rubber component (elastomer).

[0040] The white filler constituting the coating layer 23 preferably contains 20 phr to 55 phr of calcium carbonate. Thereby, the relative permittivity of the coating layer 23 can be made relatively low, and the communication performance of the transponder 20 can be effectively improved. However, if the white filler contains an excessive amount of calcium carbonate, it becomes brittle and the strength as the coating layer 23 decreases, which is not preferable. In addition to calcium carbonate, the coating layer 23 can optionally contain 20 phr or less of silica (white filler) and 5 phr or less of carbon black. When a small amount of silica and carbon black are used in combination, the relative permittivity can be decreased while ensuring the strength of the coating layer 23.

[0041] Also, the relative permittivity of the coating layer 23 is preferably 7 or less, more preferably 2 to 5. By appropriately setting the relative permittivity of the coating layer 23 in this way, the radio wave transmissivity when the transponder 20 emits radio waves can be ensured, and the communication performance of the transponder 20 can be effectively improved. Note that the relative permittivity of the rubber constituting the coating layer 23 is the relative permittivity at 860 MHz to 960 MHz at normal temperature. Here, normal temperature conforms to the standard state of JIS standards, which is 23 ± 2°C and 60% ± 5% RH. The relative permittivity of the rubber is measured by the capacitance method after being treated at 23°C and 60% RH for 24 hours. The above-mentioned range of 860 MHz to 960 MHz corresponds to the currently allocated frequencies of UHF band RFID. If the above-mentioned allocated frequencies are changed, the relative permittivity in the range of the allocated frequencies may be defined as described above.

[0042] The thickness t of the coating layer 23 is preferably 0.5 mm to 3.0 mm, more preferably 1.0 mm to 2.5 mm. Here, the thickness t of the coating layer 23 is the rubber thickness at the position including the transponder 20. For example, as shown in FIG. 4, it is the total rubber thickness of the thickness t1 and the thickness t2 on a straight line passing through the center of the transponder 20 and perpendicular to the tire surface (in FIG. 4, the outer surface of the tire). By appropriately setting the thickness t of the coating layer 23 in this way, the communication performance of the transponder 20 can be effectively improved without causing unevenness on the tire surface. Here, if the thickness t of the coating layer 23 is less than 0.5 mm, the effect of improving the communication performance of the transponder 20 cannot be obtained. Conversely, if the thickness t of the coating layer 23 exceeds 3.0 mm, unevenness will occur on the tire surface, which is not preferable in terms of appearance. Note that the cross-sectional shape of the coating layer 23 is not particularly limited. For example, a triangle, a rectangle, a trapezoid, or a spindle shape can be adopted. The coating layer 23 in FIG. 4 has a substantially spindle-shaped cross-sectional shape.

[0043] In the above pneumatic tire, the transponder 20 is preferably disposed between a position P1 which is 15 mm radially outward from the upper end 5e (the radially outer end of the tire) of the bead core 5 and a position P2 where the maximum width of the tire, as a disposition region in the tire radial direction. That is, the transponder 20 is preferably disposed in the region S1 shown in FIG. 2. When the transponder 20 is disposed in the region S1, since the transponder 20 is located in a region where the stress amplitude during running is small, the durability of the transponder 20 can be effectively improved, and furthermore, the durability of the tire is not deteriorated. Here, if the transponder 20 is disposed radially inward of the position P1, it tends to be close to a metal member such as the bead core 5, so the communication performance of the transponder 20 tends to deteriorate. On the other hand, if the transponder 20 is disposed radially outward of the position P2, the transponder 20 is located in a region where the stress amplitude during running is large, and breakage of the transponder 20 itself or interfacial peeling around the transponder 20 is likely to occur, which is not preferable.

[0044] As shown in FIG. 3, on the tire circumference, there are a plurality of splice portions where the ends of tire constituent members are overlapped. FIG. 3 shows the position Q in the tire circumferential direction of each splice portion. The center of the transponder 20 is preferably arranged at a distance of 10 mm or more from the splice portion of the tire constituent member in the tire circumferential direction. That is, the transponder 20 is preferably arranged in the region S2 shown in FIG. 3. Specifically, it is preferable that the IC substrate 21 constituting the transponder 20 is separated from the position Q by 10 mm or more in the tire circumferential direction. Further, it is more preferable that the entire transponder 20 including the antenna 22 is separated from the position Q by 10 mm or more in the tire circumferential direction, and most preferably, the entire transponder 20 in a state covered with the covering rubber is separated from the position Q by 10 mm or more in the tire circumferential direction. Further, as the tire constituent member arranged separately from the transponder 20, it is preferable that it is the sidewall rubber layer 12 or the rim cushion rubber layer 13 arranged adjacent to the transponder 20, or the carcass layer 4. By arranging the transponder 20 separated from the splice portion of the tire constituent member in this way, the durability of the tire can be effectively improved.

[0045] In addition, in the embodiment of FIG. 3, an example in which the positions Q in the tire circumferential direction of the splice portions of each tire constituent member are arranged at equal intervals is shown, but the present invention is not limited to this. The position Q in the tire circumferential direction can be set at an arbitrary position, and in any case, the transponder 20 is arranged so as to be separated from the splice portion of each tire constituent member by 10 mm or more in the tire circumferential direction.

[0046] As shown in Fig. 4, the distance d between the center of the cross-section of the transponder 20 and the tire surface is preferably 1 mm or more. By separating the transponder 20 from the tire surface in this way, the durability of the tire can be effectively improved, and the puncture resistance of the tire can also be improved. In the embodiment of Fig. 4, the distance d is the distance between the center of the cross-section of the transponder 20 and the outer surface of the tire. However, when the transponder 20 is arranged at a position close to the inner liner layer 9, the distance d is the distance between the center of the cross-section of the transponder 20 and the inner surface of the tire. In particular, the distance d between the center of the cross-section of the transponder 20 and the outer surface of the tire is preferably 2 mm or more.

[0047] In the above-described embodiment, an example is shown in which the terminal 4e of the turned-up portion 4B of the carcass layer 4 is arranged near the upper end 6e of the bead filler 6. However, the present invention is not limited thereto, and the terminal 4e of the turned-up portion 4B of the carcass layer 4 can be arranged at an arbitrary height.

Example

[0048] In a pneumatic tire having a tire size of 265 / 40ZR20, a tread portion extending in the tire circumferential direction and forming an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged on the inner side in the tire radial direction of these sidewall portions, a transponder is embedded outside the tire width direction from the carcass layer. The transponder is covered with a coating layer. Tires of Comparative Examples 1 to 2 and Examples 1 to 11 were manufactured in which the position of the transponder in the tire radial direction, the secant modulus of elasticity at 20°C when the coating layer was deformed by 10%, the storage modulus of elasticity E'c(20°C) of the coating layer, E'c(20°C) / E'out(20°C), the relative permittivity of the coating layer, and the thickness of the coating layer were set as shown in Table 1.

[0049] In Comparative Examples 1 to 2 and Examples 1 to 11, columnar transponders were used, the circumferential distance of the tire from the center of the transponder to the splice portion of the tire component was set to 10 mm, and the distance from the center of the cross-section of the transponder to the outer surface of the tire was set to 2 mm or more.

[0050] In Table 1, the position of the transponder in the tire diameter direction corresponds to each of the positions A to E shown in FIG. 6.

[0051] For these test tires, tire evaluation (durability) and transponder evaluation (communication performance and durability) were carried out by the following test methods, and the results are shown together in Table 1.

[0052] Durability (tire and transponder): Each test tire was assembled on a wheel with a standard rim, and a running test was carried out on a drum tester under the conditions of an air pressure of 120 kPa, 102% of the maximum load, and a running speed of 81 km. The running distance at the time of tire failure was measured. The evaluation results are shown as an index with Comparative Example 1 as 100. The larger this index value, the better the durability of the tire. Furthermore, for each test tire after running, the communication ability and the presence or absence of damage of the transponder were confirmed. The case where communication was possible and there was no damage was indicated as "◎ (excellent)", the case where communication was possible but there was damage was indicated as "○ (good)", and the case where communication was impossible was indicated in three levels of "× (impossible)".

[0053] Communication performance (transponder): For each test tire, communication work with the transponder was carried out using a reader / writer. Specifically, the longest communicable distance was measured with an output of 250 mW and a carrier frequency of 860 MHz to 960 MHz in the reader / writer. The evaluation results are shown as an index with Comparative Example 1 as 100. The larger this index value, the better the communication performance.

[0054]

Table 1

[0055] As can be seen from this Table 1, the pneumatic tires of Examples 1 to 11 had a well-balanced improvement in tire durability and transponder durability compared to Comparative Examples 1 and 2.

[0056] In Comparative Example 1, since the secant modulus at 20°C when the coating layer was deformed by 10% was too low, the durability of the transponder was poor. In Comparative Example 2, since the secant modulus at 20°C when the coating layer was deformed by 10% was too high, the durability of the tire was poor.

Explanation of Signs

[0057] 1 Tread portion 2 Sidewall portion 3 Bead portion 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 12 Sidewall rubber layer 13 Rim cushion rubber layer 20 Transponder 23 Coating layer CL Tire center line

Claims

1. In a pneumatic tire comprising a tread portion extending in the circumferential direction of the tire and having an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of these sidewall portions, a transponder is embedded in the tire, the transponder is covered by a covering layer, and the secant modulus of elasticity at 20 ° C. when the covering layer is deformed by 10% is in the range of 0.5 MPa to 5.0 MPa, the storage modulus of elasticity E'c(20 ° C.) of the covering layer at 20 ° C. is in the range of 2 MPa to 12 MPa, the transponder is embedded outside the tire width direction from the carcass layer, and the storage modulus of elasticity E'c(20 ° C.) of the covering layer and the storage modulus of elasticity E'out(20 ° C.) at 20 ° C. of the rubber member having the largest storage modulus of elasticity among the rubber members located outside the tire width direction from the transponder satisfy the relationship of 0.1 ≦ E'c(20 ° C.) / E'out(20 ° C.) ≦ 1.5, a pneumatic tire, wherein the center of the transponder is arranged at a distance of 10 mm or more in the circumferential direction of the tire from the splice portion of the tire constituent member.

2. The pneumatic tire according to claim 1, wherein the relative permittivity of the covering layer is 7 or less.

3. The pneumatic tire according to claim 1 or 2, wherein the covering layer is composed of rubber or an elastomer and a white filler of 20 phr or more.

4. The pneumatic tire according to claim 3, wherein the white filler contains calcium carbonate of 20 phr to 55 phr.

5. The pneumatic tire according to any one of claims 1 to 4, wherein the transponder is arranged between a position 15 mm radially outward from the upper end of the bead core of the bead portion and the maximum tire width position.

6. The pneumatic tire according to any one of claims 1 to 5, wherein the distance between the cross-sectional center of the transponder and the tire surface is 1 mm or more.

7. The pneumatic tire according to any one of claims 1 to 6, wherein the thickness of the covering layer is 0.5 mm to 3.0 mm.

8. The pneumatic tire according to any one of claims 1 to 7, wherein the transponder has an IC substrate for storing data and an antenna for transmitting and receiving data, and the antenna is spiral.

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