pneumatic tires

Abstract

To provide a pneumatic tire which allows for improvement of durability of the tire while securing a communication property and durability of a transponder.SOLUTION: A transponder 20 is buried outside a carcass layer 4 in a tire width direction. A storage elastic modulus E'out(50°C) at 50°C and a storage elastic modulus E'out(150°C) at 150°C of a rubber element having a maximum storage elastic modulus at 20°C of rubber elements located outside the transponder 20 in the tire width direction satisfies the relation of 1.0≤E'out(50°C) / E'out(150°C)≤2.0. A storage elastic modulus E'in(50°C) at 50°C and a storage elastic modulus E'in(150°C) at 150°C of a rubber element having a maximum storage elastic modulus at 20°C of rubber elements located inside the transponder 20 in the tire width direction satisfies the relation of 1.0≤E'in(50°C) / E'in(150°C)≤4.0.SELECTED DRAWING: Figure 1

Description

Technical Field

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

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 the transponder is embedded in the tire, there is a problem that when the tire generates heat during high-speed driving and the rubber member around the transponder softens, the durability of the tire deteriorates. Further, when the transponder is disposed inside the tire width direction of the carcass layer, radio waves may be blocked by tire constituent members (for example, metal members such as a carcass made of steel and a reinforcement) during communication of the transponder, and the communication performance of the transponder may deteriorate. Furthermore, depending on the physical properties of the rubber member adjacent to the inside or outside of the transponder in the tire width direction, stress concentration may occur during tire deformation, and the durability of the transponder may deteriorate.

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 tire while ensuring the communication performance and durability of the transponder.

Means for Solving the Problems

[0005] To achieve the above objective, the pneumatic tire of the present invention comprises a tread portion extending in the circumferential direction of the tire 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 radially inward of these sidewall portions, with the outer circumference of the bead core of each bead portion Triangular cross-section In a pneumatic tire in which a bead filler is positioned and a carcass layer is mounted between the pair of bead portions, the bead filler is located outside the carcass layer in the tire width direction and is located outside the carcass layer. The outermost point in the radial direction of the tire The transponder is embedded further inward in the tire radial direction, and among the rubber members located outward from the transponder in the tire width direction, the rubber member with the largest storage modulus at 20°C has a storage modulus at 50°C E'out(50°C) and a storage modulus at 150°C E'out(150°C) that satisfies the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 2.0, and among the rubber members located inward from the transponder in the tire width direction, The rubber member with the largest storage modulus at 20°C satisfies the relationship 1.0 ≤ E'in(50°C) / E'in(150°C) ≤ 4.0 for both the storage modulus at 50°C E'in(50°C) and the storage modulus at 150°C E'in(150°C), and the storage modulus at 50°C E'out(50°C) is in the range of 7 MPa to 10 MPa, and the storage modulus at 50°C E'in(50°C) is in the range of 7 MPa to 80 MPa. Furthermore, the pneumatic tire of the present invention comprises a tread portion extending in the circumferential direction of the tire 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 radially inward of these sidewall portions, with the outer circumference of the bead core of each bead portion Triangular cross-section In a pneumatic tire in which a bead filler is positioned and a carcass layer is mounted between the pair of bead portions, the bead filler is located outside the carcass layer in the tire width direction and is located outside the carcass layer. The outermost point in the radial direction of the tireThe transponder is embedded further outward in the tire radial direction, and among the rubber members located outward from the transponder in the tire width direction, the rubber member with the largest storage modulus at 20°C satisfies the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 2.0 for the rubber member with the largest storage modulus at 20°C, and among the rubber members located inward from the transponder in the tire width direction, the rubber member with the largest storage modulus at 20°C satisfies the relationship 1.0 ≤ E'in(50°C) / E'in(150°C) ≤ 4.0 for the rubber member with the largest storage modulus at 50°C, and the storage modulus at 50°C E'out(50°C) is in the range of 2 MPa to 4 MPa, and the storage modulus at 50°C E'in(50°C) is in the range of 2 MPa to 6 MPa. [Effects of the Invention]

[0006] In this invention, since the transponder is embedded outside the carcass layer in the tire width direction, there are no tire components that block radio waves during transponder communication, thus ensuring the transponder's communication capabilities. Furthermore, the storage modulus E'out(50°C) and E'out(150°C) of the rubber component located outside the transponder in the tire width direction with the highest storage modulus at 20°C, and the storage modulus E'in(50°C) and E'in(150°C) of the rubber component located inside the transponder in the tire width direction with the highest storage modulus at 20°C, respectively, satisfy the above-mentioned relationship. As a result, even when the tire reaches high temperatures, the rigidity of the rubber components located inside and outside the transponder is maintained, ensuring sufficient strength and suppressing stress concentration during tire deformation. This improves tire durability while ensuring the durability of the transponder.

[0007] In the pneumatic tire of the present invention, the transponder is covered by a coating layer, and it is preferable that the storage modulus E'c(20°C) of the coating layer at 20°C and the storage modulus E'a(20°C) of the rubber member adjacent to the coating layer on the outer side in the tire width direction satisfy the relationship 0.1 ≤ E'c(20°C) / E'a(20°C) ≤ 1.5. As a result, the physical properties of the coating layer and the rubber member adjacent to the coating layer become similar, so a stress distribution effect during driving can be obtained, and the durability of the transponder can be effectively improved.

[0008] The transponder is covered with a coating layer, and it is preferable that the storage modulus E'c(60°C) of the coating layer at 60°C and the storage modulus E'a(60°C) of the rubber member adjacent to the coating layer on the outer side in the tire width direction satisfy the relationship 0.2 ≤ E'c(60°C) / E'a(60°C) ≤ 1.2. As a result, the physical properties of the coating layer and the rubber member adjacent to the coating layer become similar, which allows for a stress distribution effect during driving and effectively improves the durability of the transponder.

[0009] The transponder is covered with a coating layer, and the storage modulus E'c(20°C) of the coating layer at 2°C is preferably in the range of 2 MPa to 12 MPa. This effectively improves the durability of the transponder.

[0010] The transponder is covered with a coating layer, and it is preferable that the storage modulus E'c(20°C) of the coating layer at 20°C and the storage modulus E'c(60°C) of the coating layer at 60°C satisfy the relationship 1.0 ≤ E'c(20°C) / E'c(60°C) ≤ 1.5. This reduces the temperature dependence of the coating layer, so that the coating layer does not soften even when the tire temperature rises during high-speed driving, and the durability of the transponder can be effectively improved.

[0011] The transponder is covered with a coating layer, preferably with a dielectric constant of 7 or less. This protects the transponder from the coating layer, improving its durability, ensuring its radio wave transparency, and effectively improving its communication performance.

[0012] The transponder is covered with a coating layer, which preferably consists of rubber or elastomer and a white filler of 20 phr or more. This allows for a relatively lower dielectric constant of the coating layer compared to cases containing carbon, and effectively improves the communication performance of the transponder.

[0013] The white filler preferably contains 20 phr to 55 phr of calcium carbonate. This allows for a relatively low dielectric constant of the coating layer, effectively improving the communication performance of the transponder.

[0014] It is preferable that the center of the transponder is positioned at least 10 mm away from the splice portion of the tire component in the circumferential direction of the tire. This effectively improves the durability of the tire.

[0015] It is preferable to position the transponder between a position 15 mm radially outward from the upper end of the bead core of the bead portion and the position of the tire's maximum width. This positions the transponder in a region where the stress amplitude during driving is small, thereby effectively improving the transponder's durability without reducing the tire's durability.

[0016] The distance between the center of the transponder's cross-section and the outer surface of the tire is preferably 2 mm or more. This effectively improves the tire's durability and its resistance to damage.

[0017] The transponder is coated with a coating layer, and 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 irregularities on the outer surface of the tire.

[0018] 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.

[0019] In the present invention, the storage elastic modulus E' is measured in accordance with JIS-K6394 using a viscoelastic spectrometer under the conditions of each specified temperature, a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain of ±2% in a tensile deformation mode.

Brief Description of Drawings

[0020] [Figure 1] It is a meridian half-sectional view showing a pneumatic tire according to an embodiment of the present invention. [Figure 2] It is a meridian sectional view schematically showing the pneumatic tire of FIG. 1. [Figure 3] It is an equatorial sectional view schematically showing the pneumatic tire of FIG. 1. [Figure 4] It is a sectional view showing an enlarged view of the transponder embedded in the pneumatic tire of FIG. 1. [Figure 5] (a) and (b) are perspective views showing a transponder that can be embedded in a pneumatic tire according to the present invention. [Figure 6] It is an explanatory view showing the tire radial position of the transponder in the test tire.

Embodiments for Carrying Out the Invention

[0021] 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.

[0022] As shown in Figure 1, the pneumatic tire of this embodiment comprises a tread portion 1 that extends in the circumferential direction of the tire and forms an annular shape, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged radially inward of these sidewall portions 2.

[0023] Between a pair of bead sections 3, at least one carcass layer 4 (one layer in Figure 1) is installed, which consists of multiple carcass cords arranged in a radial direction. The carcass layer 4 is covered with rubber. Organic fiber cords such as nylon or polyester are preferably used as the carcass cords that make up the carcass layer 4. An annular bead core 5 is embedded in each bead section 3, and a bead filler 6 made of a rubber composition with a triangular cross-section is arranged on the outer circumference of the bead core 5.

[0024] On the other hand, multiple belt layers 7 (two layers in Figure 1) are embedded on the outer circumference side of the carcass layer 4 in the tread portion 1. The belt layers 7 include multiple reinforcing cords that are inclined with respect to the tire's circumferential direction, and the reinforcing cords are arranged so as to intersect each other between layers. In the belt layers 7, the inclination angle of the reinforcing cords with respect to the tire's circumferential direction is set to, for example, a range of 10° to 40°. Steel cords are preferably used as the reinforcing cords in the belt layers 7.

[0025] On the outer circumference side of the belt layer 7, at least one belt cover layer 8 (two layers in Figure 1) is arranged, with reinforcing cords arranged at an angle of, for example, 5° or less with respect to the circumferential direction of the tire, for the purpose of improving high-speed durability. In Figure 1, the belt cover layer 8 located on the inner side in the radial direction of the tire constitutes a full cover that covers the entire width of the belt layer 7, while the belt cover layer 8 located on the outer side in the radial direction of the tire constitutes an edge cover layer that covers only the ends of the belt layer 7. Organic fiber cords such as nylon or aramid are preferably used as the reinforcing cords of the belt cover layer 8.

[0026] In the above-described pneumatic tire, both ends 4e of the carcass layer 4 are folded back from the inside to the outside of the tire around each bead core 5, and are arranged to enclose the bead core 5 and the bead filler 6. The carcass layer 4 includes a main body portion 4A which extends from the tread portion 1 through each sidewall portion 2 to each bead portion 3, and a winding portion 4B which is wound up around the bead core 5 in each bead portion 3 and extends toward the sidewall portion 2.

[0027] Furthermore, an inner liner layer 9 is arranged on the inner surface of the tire along the carcass layer 4. A cap tread rubber layer 11 is arranged on the tread section 1, a sidewall rubber layer 12 is arranged on the sidewall section 2, and a rim cushion rubber layer 13 is arranged on the bead section 3.

[0028] Furthermore, in the above-described pneumatic tire, a transponder 20 is embedded in a portion of the tire width direction that is outside the carcass layer 4. The transponder 20 extends along the tire circumferential direction. The transponder 20 may also be positioned at an angle of -10° to 10° with respect to the tire circumferential direction.

[0029] For example, an RFID (Radio Frequency Identification) tag can be used as the transponder 20. As shown in Figures 5(a) and (b), the transponder 20 has an IC board 21 for storing data and an antenna 22 for contactlessly transmitting and receiving data. By using such a transponder 20, information about tires can be written to or read in a timely manner, and tires can be managed efficiently. RFID is an automatic identification technology that consists of a reader / writer having an antenna and a controller, and an ID tag having an IC board and an antenna, and is capable of exchanging data wirelessly.

[0030] The overall shape of the transponder 20 is not particularly limited; for example, as shown in Figures 5(a) and 5(b), columnar or plate-shaped transponders can be used. In particular, the columnar transponder 20 shown in Figure 5(a) is preferable because it can follow the deformation of the tire in all directions. In this case, the antenna 22 of the transponder 20 protrudes from each end of the IC substrate 21 and has a spiral shape. This allows it to follow the deformation of the tire during driving, improving the durability of the transponder 20. Furthermore, by appropriately changing the length of the antenna 22, communication can be ensured.

[0031] Furthermore, in the above-described pneumatic tire, among the rubber components located outside the transponder 20 in the tire width direction (the sidewall rubber layer 12 and rim cushion rubber layer 13 in Figure 1), the rubber component with the largest storage modulus at 20°C (hereinafter sometimes referred to as the outer component) corresponds to the rim cushion rubber layer 13. On the other hand, among the rubber components located inside the transponder 20 in the tire width direction (the coating rubber of the carcass layer 4, the bead filler 6, and the inner liner layer 9 in Figure 1), the rubber component with the largest storage modulus at 20°C (hereinafter sometimes referred to as the inner component) corresponds to the bead filler 6. Note that the coating layer 23 covering the transponder 20, which will be described later, is not included as the rubber component with the largest storage modulus at 20°C (outer component or inner component).

[0032] Here, the storage modulus E'out(50°C) at 50°C and E'out(150°C) at 150°C in the outer member satisfy the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 2.0, and the storage modulus E'in(50°C) at 50°C and E'in(150°C) at 150°C in the inner member satisfy the relationship 1.0 ≤ E'in(50°C) / E'in(150°C) ≤ 4.0. In particular, it is preferable that the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 1.6 and 1.1 ≤ E'in(50°C) / E'in(150°C) ≤ 2.5 is satisfied.

[0033] In this case, in the region radially inward from the apex of the bead filler 6, the storage modulus E'out(20°C) of the outer material at 20°C can be set in the range of 8MPa to 12MPa, and the storage modulus E'in(20°C) of the inner material at 20°C can be set in the range of 8MPa to 110MPa. Furthermore, the storage modulus E'out(50°C) of the outer material at 50°C can be set in the range of 7MPa to 10MPa, and the storage modulus E'in(50°C) of the inner material at 50°C can be set in the range of 7MPa to 80MPa. In addition, in the flex zone radially outward from the apex of the bead filler 6, the storage modulus E'out(20°C) of the outer material at 20°C can be set in the range of 3MPa to 5MPa, and the storage modulus E'in(20°C) of the inner material at 20°C can be set in the range of 5MPa to 7MPa. Furthermore, the storage modulus E'out(50°C) of the outer member at 50°C can be set in the range of 2MPa to 4MPa, and the storage modulus E'in(50°C) of the inner member at 50°C can be set in the range of 2MPa to 6MPa.

[0034] In the embodiment shown in Figure 1, the transponder 20 is shown as being positioned between the winding portion 4B of the carcass layer 4 and the rim cushion rubber layer 13, but it is not limited to this. In addition, the transponder 20 can be positioned between the main body portion 4A of the carcass layer 4 and the sidewall rubber layer 12. The outer and inner members will change depending on the position of the transponder 20, but in any case, the storage modulus of elasticity E'out(50°C) and E'out(150°C) of the outer member at 50°C and E'in(50°C) and E'in(150°C) of the inner member at 50°C are set to satisfy the above-described relationship.

[0035] In the pneumatic tire described above, the transponder 20 is embedded outside the carcass layer 4 in the tire width direction. Therefore, there are no tire components that block radio waves during communication by the transponder 20, and the communication capabilities of the transponder 20 can be ensured. Furthermore, among the rubber components located outside the transponder 20 in the tire width direction, the storage modulus E'out(50°C) at 50°C and E'out(150°C) at 150°C of the rubber component with the largest storage modulus at 20°C satisfy the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 2.0. Among the rubber components located inside the transponder 20 in the tire width direction, the storage modulus E'in(50°C) at 50°C and E'in(150°C) at 150°C of the rubber component with the largest storage modulus at 20°C satisfy the relationship 1.0 ≤ E'in(50°C) / E'in(150°C) ≤ 4.0. Therefore, even when the tire reaches high temperatures, the rigidity of the rubber components located inside and outside the transponder 20 is maintained, ensuring sufficient strength and suppressing stress concentration during tire deformation. This improves the durability of the tire while ensuring the durability of the transponder 20.

[0036] Generally, for components with high temperature dependence (easily generate heat), the storage modulus in the high-temperature range (e.g., 150°C) tends to be lower than that in the medium-temperature range (e.g., 50°C) when the temperature rises, and the ratio of the storage modulus in the medium-temperature range to the storage modulus in the high-temperature range exceeds 1.0. Conversely, if the value of E'out(50°C) / E'out(150°C) or E'in(50°C) / E'in(150°C) is smaller than the lower limit, stress concentration occurs in the rubber component located inside or outside the transponder 20 during tire deformation, worsening the durability of the transponder 20. On the other hand, if the value of E'out(50°C) / E'out(150°C) or E'in(50°C) / E'in(150°C) is greater than the upper limit, as the tire temperature rises, the rigidity of the rubber component located inside or outside the transponder 20 tends to decrease compared to when it is at 50°C, leading to a decrease in the strength of the rubber component and a reduction in the durability of the tire.

[0037] Furthermore, regarding the relationship between the temperature dependence of the physical properties of the outer material and the temperature dependence of the physical properties of the inner material, in order to enhance the protection of the transponder 20 against tire deformation during driving, it is preferable that the relationship 0.2 × E'in(50℃) / E'in(150℃) ≤ E'out(50℃) / E'out(150℃) ≤ 1.8 × E'in(50℃) / E'in(150℃) is satisfied. In particular, when the JIS hardness (20℃) of the inner material is relatively high, the value of E'in(50℃) / E'in(150℃) is greater than the value of E'out(50℃) / E'out(150℃) (the inner material has a higher temperature dependence than the outer material), and since the inner material softens more easily at high temperatures, the protection of the transponder 20 can be enhanced by the buffering effect. Furthermore, when the JIS hardness (20°C) of the internal components is relatively low, the values ​​of E'in(50°C) / E'in(150°C) and E'out(50°C) / E'out(150°C) are almost the same. This suppresses stress concentration around the transponder 20, which is also effective in improving tire durability.

[0038] In the above-described pneumatic tire, the transponder 20 is preferably positioned between a position P1 15 mm radially outward from the upper end 5e (outer end in the tire's radial direction) of the bead core 5 and a position P2 that represents the tire's maximum width. That is, the transponder 20 is preferably positioned in region S1 as shown in Figure 2. When the transponder 20 is positioned in region S1, it is located in a region where the stress amplitude during driving is small, thus effectively improving the durability of the transponder 20 and without reducing the durability of the tire. Here, if the transponder 20 is positioned radially inward from position P1, it will be closer to metal components such as the bead core 5, which tends to worsen the communication performance of the transponder 20. On the other hand, if the transponder 20 is positioned radially outward from position P2, it will be located in a region where the stress amplitude during driving is large, making it more susceptible to damage to the transponder 20 itself and interfacial delamination around the transponder 20, which is undesirable.

[0039] As shown in Figure 3, there are multiple splice sections on the circumference of the tire, formed by overlapping ends of tire components. Figure 3 shows the position Q of each splice section in the tire circumferential direction. It is preferable that the center of the transponder 20 is positioned at least 10 mm away from the splice sections of the tire components in the tire circumferential direction. That is, it is preferable that the transponder 20 is positioned in region S2 shown in Figure 3. Specifically, it is preferable that the IC substrate 21 constituting the transponder 20 is positioned at least 10 mm away from position Q in the tire circumferential direction. Furthermore, it is even more preferable that the entire transponder 20, including the antenna 22, is positioned at least 10 mm away from position Q in the tire circumferential direction, and it is most preferable that the entire transponder 20, covered with the covering rubber, is positioned at least 10 mm away from position Q in the tire circumferential direction. In addition, it is preferable that the tire component positioned at a distance from the transponder 20 is a sidewall rubber layer 12 or rim cushion rubber layer 13, or a carcass layer 4, which are positioned adjacent to the transponder 20. By positioning the transponder 20 at a distance from the splice portion of the tire components in this manner, the durability of the tire can be effectively improved.

[0040] In the embodiment shown in Figure 3, an example is shown in which the positions Q in the circumferential direction of the tire at the splice portions of each tire component are arranged at equal intervals, but the invention is not limited to this. The positions Q in the circumferential direction of the tire can be set to any position, and in any case, the transponder 20 is positioned so as to be at least 10 mm away from the splice portions of each tire component in the circumferential direction of the tire.

[0041] As shown in Figure 4, it is preferable that the distance d between the center of the cross-section of the transponder 20 and the outer surface of the tire is 2 mm or more. By separating the transponder 20 from the outer surface of the tire in this way, the durability of the tire can be effectively improved, as well as the tire's resistance to damage.

[0042] Furthermore, the transponder 20 is preferably covered by a coating layer 23. This coating layer 23 covers the entire transponder 20 by sandwiching both the front and back surfaces of the transponder 20. The coating layer 23 may be made of rubber having the same physical properties as the rubber constituting the sidewall rubber layer 12 or the rim cushion rubber layer 13, or it may be made of rubber having different physical properties. By protecting the transponder 20 with the coating layer 23, the durability of the transponder 20 can be improved.

[0043] The following describes in detail the coating layer 23 that covers the transponder 20. Regarding the physical properties of the coating layer 23, the storage modulus E'c(20°C) of the coating layer 23 at 2°C should ideally be in the range of 2 MPa to 12 MPa. By setting the physical properties of the coating layer 23 in this way, the durability of the transponder 20 can be effectively improved.

[0044] The storage modulus E'c(20°C) of the coating layer 23 at 20°C and the storage modulus E'c(60°C) of the coating layer 23 at 60°C should satisfy the relationship 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 (the coating layer 23 becomes less prone to generating heat), so even if the tire temperature rises during high-speed driving, the coating layer 23 does not soften, and the durability of the transponder 20 can be effectively improved.

[0045] Furthermore, it is preferable that the storage modulus E'c(20°C) of the coating layer 23 at 20°C and the storage modulus E'a(20°C) of the rubber member adjacent to the coating layer 23 on the tire width side (rim cushion rubber layer 13 in Figure 4) at 20°C satisfy the relationship 0.1 ≤ E'c(20°C) / E'a(20°C) ≤ 1.5, and more preferably that it satisfy the relationship 0.15 ≤ E'c(20°C) / E'a(20°C) ≤ 1.30. By setting the physical properties of the coating layer 23 and the rubber member adjacent to the coating layer 23 in this way, the physical properties of both become similar, which allows for a stress distribution effect during driving and effectively improves the durability of the transponder 20.

[0046] It is preferable that the storage modulus E'c(60°C) of the coating layer 23 at 60°C and the storage modulus E'a(60°C) of the rubber member adjacent to the coating layer 23 on the outer side in the tire width direction satisfy the relationship 0.2 ≤ E'c(60°C) / E'a(60°C) ≤ 1.2. By setting the physical properties of the coating layer 23 and the rubber member adjacent to the coating layer 23 in this way, the physical properties of both become similar, thereby achieving a stress distribution effect during driving and effectively improving the durability of the transponder 20.

[0047] Preferably, the coating layer 23 consists of rubber or elastomer and a white filler of 20 phr or more. By configuring the coating layer 23 in this way, the dielectric constant of the coating layer 23 can be made relatively low compared to when carbon is included, 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).

[0048] The white filler constituting this coating layer 23 preferably contains calcium carbonate in a concentration of 20 phr to 55 phr. This allows the dielectric constant of the coating layer 23 to be relatively low, effectively improving the communication performance of the transponder 20. However, if the white filler contains an excessive amount of calcium carbonate, it becomes brittle, reducing the strength of the coating layer 23, which is undesirable. In addition to calcium carbonate, the coating layer 23 may optionally contain silica (white filler) of 20 phr or less, or carbon black of 5 phr or less. When small amounts of silica or carbon black are used in combination, the dielectric constant of the coating layer 23 can be reduced while maintaining its strength.

[0049] Furthermore, the relative permittivity of the coating layer 23 is preferably 7 or less, and more preferably 2 to 5. By appropriately setting the relative permittivity of the coating layer 23 in this way, radio wave transparency when the transponder 20 radiates radio waves can be ensured, and the communication performance of the transponder 20 can be effectively improved. The relative permittivity of the rubber constituting the coating layer 23 is 860 MHz to 960 MHz at room temperature. Here, room temperature conforms to the standard conditions of the JIS standard, which is 23 ± 2°C and 60% ± 5% RH. The rubber is treated at 23°C and 60% RH for 24 hours, and then the relative permittivity is measured by the capacitance method. The above-mentioned range of 860 MHz to 960 MHz corresponds to the current allocated frequencies for RFID in the UHF band, but if the above allocated frequencies are changed, the relative permittivity for the range of those allocated frequencies should be defined as described above.

[0050] The thickness t of the coating layer 23 is preferably 0.5 mm to 3.0 mm, and more preferably 1.0 mm to 2.5 mm. Here, the thickness t of the coating layer 23 is the rubber thickness at the location including the transponder 20, and is the sum of the thickness t1 and thickness t2 on a straight line passing through the center of the transponder 20 and perpendicular to the outer surface of the tire, as shown in Figure 4. By setting the thickness t of the coating layer 23 appropriately in this way, the communication performance of the transponder 20 can be effectively improved without causing irregularities on the outer surface of the tire. Here, if the thickness t of the coating layer 23 is thinner than 0.5 mm, the effect of improving the communication performance of the transponder 20 cannot be obtained, and conversely, if the thickness t of the coating layer 23 exceeds 3.0 mm, irregularities will occur on the outer surface of the tire, which is undesirable in appearance. The cross-sectional shape of the coating layer 23 is not particularly limited, but for example, a triangle, rectangle, trapezoid, or spindle shape can be adopted. The coating layer 23 in Figure 4 has a roughly spindle-shaped cross-section.

[0051] In the embodiment described above, an example was shown in which the terminal 4e of the winding portion 4B of the carcass layer 4 is positioned near the upper end 6e of the bead filler 6. However, the embodiment is not limited to this, and the terminal 4e of the winding portion 4B of the carcass layer 4 can be positioned at any height. For example, the terminal 4e of the winding portion 4B of the carcass layer 4 may be positioned to the side of the bead core 5. In such a low turn-up structure, the transponder 20 can be positioned between the bead filler 6 and the sidewall rubber layer 12 or the rim cushion rubber layer 13. In this case, the rubber member adjacent to the outer side of the covering layer 23 in the tire width direction is the sidewall rubber layer 12 or the rim cushion rubber layer 13. [Examples]

[0052] In a pneumatic tire with a tire size of 265 / 40ZR20, comprising a tread portion extending in the circumferential direction of the tire 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 radially inward of these sidewall portions, with a carcass layer mounted between the pair of bead portions, a transponder is embedded, and the position of the transponder in the tire width direction, the position of the transponder in the tire radial direction, E'ou Comparative Examples 1-4 and Examples 1-14 tires were manufactured with the following settings: t(50℃) / E'out(150℃), E'in(50℃) / E'in(150℃), presence or absence of a coating layer, relative permittivity of the coating layer, thickness of the coating layer, storage modulus of the coating layer E'c(20℃), storage modulus of the coating layer E'c(60℃), E'c(20℃) / E'a(20℃), E'c(60℃) / E'a(60℃), and E'c(20℃) / E'c(60℃) as shown in Tables 1 and 2.

[0053] In Comparative Examples 1-4 and Examples 1-14, a columnar transponder was used, the circumferential distance 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 transponder's cross-section to the outer surface of the tire was set to 2 mm or more.

[0054] In Tables 1 and 2, when the transponder's position in the tire width direction is "inside," it means the transponder is located on the inside of the carcass layer in the tire width direction, and when the transponder's position in the tire width direction is "outside," it means the transponder is located on the outside of the carcass layer in the tire width direction. Also, in Tables 1 and 2, the transponder's position in the tire radial direction corresponds to positions A to E shown in Figure 6.

[0055] In Comparative Examples 2-4 and Examples 1-14, the outer component is the rim cushion rubber layer, and the inner component is the bead filler. That is, in Tables 1 and 2, "E'out(50°C) / E'out(150°C)" is the ratio of the storage modulus of the rim cushion rubber layer, which is the outer component, and "E'in(50°C) / E'in(150°C)" is the ratio of the storage modulus of the bead filler, which is the inner component. Also, "E'c(20°C) / E'a(20°C)" and "E'c(60°C) / E'a(60°C)" are the ratio of the storage modulus of the coating layer to the storage modulus of the rim cushion rubber layer, which is the rubber component adjacent to the outer side of the coating layer in the tire width direction. "E'c(20°C) / E'c(60°C)" is the ratio of the storage modulus of the coating layer. For Comparative Example 1, for convenience, the physical properties of the rim cushion rubber layer were shown as the physical properties of the outer component, and the physical properties of the bead filler were shown as the physical properties of the inner component.

[0056] These test tires were evaluated for tire performance (durability) and transponder performance (communication and durability) using the test methods described below, and the results are shown in Tables 1 and 2.

[0057] Durability (tires and transponders): Each test tire was mounted on a standard rim wheel, and a running test was conducted on a drum testing machine under the conditions of an air pressure of 120 kPa, 102% of the maximum load, and a running speed of 81 km / h. The distance traveled when the tire failed was measured. The evaluation results are shown as an index with Comparative Example 2 set to 100. A higher index value indicates better tire durability. Furthermore, after the running test, the transponder's communication capability and damage status were checked for each test tire. "◎ (Excellent)" was used to indicate communication capability and no damage, "○ (Good)" was used to indicate communication capability but damage, and "× (Poor)" was used to indicate communication failure.

[0058] Transponder: For each test tire, communication with a transponder was performed using a reader / writer. Specifically, the longest possible communication distance was measured using a reader / writer with an output of 250mW and a carrier frequency of 860MHz to 960MHz. The evaluation results are shown as an index with Comparative Example 2 set to 100. A higher index value indicates better communication performance.

[0059] [Table 1]

[0060] [Table 2]

[0061] As can be seen from Tables 1 and 2, the pneumatic tires of Examples 1 to 14 showed a good balance of improved tire durability and transponder communication performance and durability compared to Comparative Example 2.

[0062] On the other hand, in Comparative Example 1, the transponder was positioned on the inside of the carcass layer in the tire width direction, resulting in poor transponder communication performance. In Comparative Examples 1 and 3, the values ​​of E'out(50°C) / E'out(150°C) or E'in(50°C) / E'in(150°C) were set lower than the range specified in the present invention, so no improvement in transponder durability was obtained. In Comparative Example 4, the values ​​of E'out(50°C) / E'out(150°C) and E'in(50°C) / E'in(150°C) were set higher than the range specified in the present invention, resulting in poor tire durability. [Explanation of Symbols]

[0063] 1. Tread section 2 Sidewall section 3. Bead section 4. Carcass layer 5 Bead core 6. Bead Filler 7 Belt layer 12 Sidewall rubber layer 13 Rim cushion rubber layer 20 transponders CL tire centerline

Claims

1. In a pneumatic tire comprising a tread portion extending in the circumferential direction of the tire 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 radially inward of these sidewall portions, a bead filler with a triangular cross-section is arranged on the outer circumference of the bead core of each bead portion, and a carcass layer is mounted between the pair of bead portions, A transponder is embedded outside the carcass layer in the tire width direction and inside the outermost point of the bead filler in the tire radial direction, and the storage modulus at 50°C E'out(50°C) and the storage modulus at 150°C E'out(150°C) of the rubber member located outside the transponder in the tire width direction have the largest storage modulus at 20°C, and the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 2.0 is satisfied, and A pneumatic tire characterized in that, among the rubber members located on the inside in the width direction of the tire, the rubber member with the largest storage modulus at 20°C satisfies the relationship 1.0 ≤ E'in(50°C) / E'in(150°C) ≤ 4.0 for the storage modulus at 50°C E'in(50°C) and the storage modulus at 150°C E'in(50°C). The storage modulus at 50°C E'out(50°C) is in the range of 7 MPa to 10 MPa, and the storage modulus at 50°C E'in(50°C) is in the range of 7 MPa to 80 MPa.

2. The pneumatic tire according to claim 1, characterized in that the transponder is covered with a coating layer, and the storage modulus of elasticity E'c(20°C) of the coating layer at 20°C and the storage modulus of elasticity E'a(20°C) of a rubber member adjacent to the outer side of the coating layer in the tire width direction satisfy the relationship 0.1 ≤ E'c(20°C) / E'a(20°C) ≤ 1.

5.

3. The pneumatic tire according to claim 1 or 2, characterized in that the transponder is covered with a coating layer, and the storage modulus of elasticity E'c(60°C) of the coating layer at 60°C and the storage modulus of elasticity E'a(60°C) of a rubber member adjacent to the outer side of the coating layer in the tire width direction satisfy the relationship 0.2 ≤ E'c(60°C) / E'a(60°C) ≤ 1.

2.

4. The pneumatic tire according to any one of claims 1 to 3, characterized in that the transponder is covered with a coating layer, and the storage modulus of elasticity E'c(20°C) of the coating layer at 2 MPa to 12 MPa is in the range of 2 MPa to 12 MPa.

5. The pneumatic tire according to any one of claims 1 to 4, characterized in that the transponder is covered with a coating layer, and the storage modulus of the coating layer at 20°C E'c(20°C) and the storage modulus of the coating layer at 60°C E'c(60°C) satisfy the relationship 1.0 ≤ E'c(20°C) / E'c(60°C) ≤ 1.

5.

6. The pneumatic tire according to any one of claims 1 to 5, characterized in that the transponder is covered with a coating layer, and the relative permittivity of the coating layer is 7 or less.

7. The pneumatic tire according to any one of claims 1 to 6, characterized in that the transponder is covered by a coating layer, and the coating layer consists of rubber or elastomer and a white filler of 20 phr or more.

8. The pneumatic tire according to claim 7, characterized in that the white filler contains 20 phr to 55 phr of calcium carbonate.

9. The pneumatic tire according to any one of claims 1 to 8, characterized in that the center of the transponder is positioned at a distance of 10 mm or more in the circumferential direction of the tire from the splice portion of the tire component.

10. The pneumatic tire according to any one of claims 1 to 9, characterized in that the transponder is positioned between a position 15 mm radially outward from the upper end of the bead core of the bead portion and the maximum width position of the tire.

11. The pneumatic tire according to any one of claims 1 to 10, characterized in that the distance between the center of the cross-section of the transponder and the outer surface of the tire is 2 mm or more.

12. The pneumatic tire according to any one of claims 1 to 11, characterized in that the transponder is covered with a coating layer, the thickness of which is 0.5 mm to 3.0 mm.

13. The pneumatic tire according to any one of claims 1 to 12, characterized in that the transponder has an IC board for storing data and an antenna for transmitting and receiving data, and the antenna is spiral-shaped.

14. In a pneumatic tire comprising a tread portion extending in the circumferential direction of the tire 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 radially inward of these sidewall portions, a bead filler with a triangular cross-section is arranged on the outer circumference of the bead core of each bead portion, and a carcass layer is mounted between the pair of bead portions, A transponder is embedded outside the carcass layer in the tire width direction and outside the outermost point of the bead filler in the tire radial direction, and among the rubber members located outside the transponder in the tire width direction, the rubber member with the largest storage modulus at 20°C has a storage modulus of 50°C E'out(50°C) and a storage modulus of 150°C E'out(150°C) that satisfies the relationship 1.0 ≤ E'out(50°C) / E'out(150°C) ≤ 2.0, and A pneumatic tire characterized in that, among the rubber members located on the inside in the tire width direction, the rubber member with the largest storage modulus at 20°C satisfies the relationship 1.0 ≤ E'in(50°C) / E'in(150°C) ≤ 4.0 for the storage modulus at 50°C E'in(50°C) and the storage modulus at 150°C E'in(150°C). The storage modulus at 50°C E'out(50°C) is in the range of 2 MPa to 4 MPa, and the storage modulus at 50°C E'in(50°C) is in the range of 2 MPa to 6 MPa.

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