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(0°C) at 0°C and a storage elastic modulus E'out(-20°C) at -20°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 0.50≤E'out(0°C) / E'out(-20°C)≤0.95. A storage elastic modulus E'in(0°C) at 0°C and a storage elastic modulus E'in(-20°C) at -20°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 0.50≤E'in(0°C) / E'in(-20°C)≤0.95.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) inside the tire (see, for example, Patent Document 1). When a transponder is embedded in a tire, in a low-temperature environment, since the tire constituent members are brittle at the start of running, failures starting from the transponder are likely to occur, and the durability of the tire may deteriorate. Further, when the transponder is disposed inside the tire in 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 transponder inside or outside 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 satisfies the relationship 0.50 ≤ E'out(0°C) / E'out(-20°C) ≤ 0.95 for the rubber member with the largest storage modulus at 20°C among the rubber members located inward from the transponder in the tire width direction, and the storage modulus at 0°C E'in(0°C) and the storage modulus at -20°C E' The invention is characterized in that in(-20℃) satisfies the relationship 0.50 ≤ E'in(0℃) / E'in(-20℃) ≤ 0.95, the storage modulus E'out(20℃) at 20℃ of the rubber member with the largest storage modulus at 20℃ among the rubber members located outside the transponder in the tire width direction is in the range of 8MPa to 12MPa, and the storage modulus E'in(20℃) at 20℃ of the rubber member with the largest storage modulus at 20℃ among the rubber members located inside the transponder in the tire width direction is in the range of 8MPa to 110MPa. 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 0.50 ≤ E'out(0°C) / E'out(-20°C) ≤ 0.95 for the rubber member with the largest storage modulus at 20°C among the rubber members located inward from the transponder in the tire width direction, and the storage modulus at 0°C E'in(0°C) and the storage modulus at -20°C The present invention satisfies the relationship E'in(-20℃) 0.50 ≤ E'in(0℃) / E'in(-20℃) ≤ 0.95, and the storage modulus E'out(20℃) of the rubber member with the largest storage modulus at 20℃ among the rubber members located outside the transponder in the tire width direction is in the range of 3 MPa to 5 MPa, and the storage modulus E'in(20℃) of the rubber member with the largest storage modulus at 20℃ among the rubber members located inside the transponder in the tire width direction is in the range of 5 MPa to 7 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, and the communication performance of the transponder can be ensured. Furthermore, the storage modulus E'out(0°C) and E'out(-20°C) of the rubber component located outside the transponder in the tire width direction with the largest storage modulus at 20°C, and the storage modulus E'in(0°C) and E'in(-20°C) of the rubber component located inside the transponder in the tire width direction with the largest storage modulus at 20°C, respectively, satisfy the above-mentioned relationship. As a result, the rigidity of the rubber components located inside and outside the transponder is maintained in low-temperature environments, ensuring sufficient strength and suppressing stress concentration during tire deformation. This makes it possible to improve tire durability while ensuring the durability of the transponder in low-temperature environments.

[0007] In the pneumatic tire of the present invention, it is preferable that the storage modulus E'out(-20°C) and storage modulus E'out(-40°C) of the rubber member located outside the transponder in the tire width direction with the largest storage modulus at 20°C satisfy the relationship 0.4 ≤ E'out(-20°C) / E'out(-40°C) ≤ 0.7, and the storage modulus E'in(-20°C) and storage modulus E'in(-40°C) of the rubber member located inside the transponder in the tire width direction with the largest storage modulus at 20°C satisfy the relationship 0.2 ≤ E'in(-20°C) / E'in(-40°C) ≤ 0.7. This makes it possible to effectively improve the durability of the tire in low-temperature environments.

[0008] The transponder is covered with a coating layer, and it is preferable that the storage modulus E'c(0°C) of the coating layer at 0°C and the storage modulus E'a(0°C) of the rubber member adjacent to the coating layer on the outside in the tire width direction satisfy the relationship 0.15 ≤ E'c(0°C) / E'a(0°C) ≤ 1.30. This makes the physical properties of the coating layer and the rubber member adjacent to the coating layer similar, thereby achieving a stress distribution effect during driving and effectively improving the durability of the transponder in low-temperature environments.

[0009] 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'a(-20°C) of the rubber member adjacent to the coating layer on the outside in the tire width direction satisfy the relationship 0.15 ≤ E'c(-20°C) / E'a(-20°C) ≤ 1.30. This makes the physical properties of the coating layer and the rubber member adjacent to the coating layer similar, thereby achieving a stress distribution effect during driving and effectively improving the durability of the transponder in low-temperature environments.

[0010] The transponder is covered with a coating layer, and the storage modulus E'c(-20°C) of the coating layer is preferably in the range of 3 MPa to 17 MPa. This effectively improves the durability of the transponder in low-temperature environments.

[0011] The transponder is covered with a coating layer, and it is preferable that the storage modulus E'c(0°C) of the coating layer at 0°C and the storage modulus E'c(-20°C) of the coating layer at -20°C satisfy the relationship 0.50 ≤ E'c(0°C) / E'c(-20°C) ≤ 0.95. This reduces the temperature dependence of the coating layer, thereby effectively improving the durability of the transponder in low-temperature environments.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] The transponder is preferably disposed between a position 15 mm radially outward of the upper end of the bead core of the bead portion and the maximum width position of the tire in the tire diameter direction. Thereby, since the transponder is disposed in a region where the stress amplitude during traveling is small, the durability of the transponder can be effectively improved, and furthermore, the durability of the tire is not reduced.

[0017] The distance between the center of the cross-section of the transponder and the outer surface of the tire is preferably 2 mm or more. Thereby, the durability of the tire can be effectively improved, and the puncture resistance of the tire can be improved.

[0018] The transponder is covered 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.

[0019] 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 traveling, and the durability of the transponder can be improved.

[0020] In the present invention, the storage elastic modulus E' is measured in accordance with JIS-K6394 using a viscoelastic spectrometer in a tensile deformation mode under the conditions of each specified temperature, a frequency of 10 Hz, an initial strain of 10%, and a dynamic strain of ±2%.

Brief Description of Drawings

[0021] [Figure 1] It is a meridian semi-cross-sectional view showing a pneumatic tire according to an embodiment of the present invention. [Figure 2] It is a meridian cross-sectional view schematically showing the pneumatic tire of FIG. 1. [Figure 3] It is an equatorial cross-sectional view schematically showing the pneumatic tire of FIG. 1. [Figure 4]It is a cross-sectional view showing an enlarged view of a 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.

Mode for Carrying Out the Invention

[0022] 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.

[0023] [[ID=1⑧]]As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and forms 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 tire radial inner side of these sidewall portions 2.

[0024] 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 periphery of the bead core 5.

[0025] On the other hand, on the tire outer peripheral side 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, for example, in the range of 10° to 40°. As the reinforcing cords of the belt layer 7, steel cords are preferably used.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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).

[0033] Here, the storage modulus E'out(0°C) at 0°C and the storage modulus E'out(-20°C) at -20°C in the outer member satisfy the relationship 0.50 ≤ E'out(0°C) / E'out(-20°C) ≤ 0.95, and the storage modulus E'in(0°C) at 0°C and the storage modulus E'in(-20°C) at -20°C in the inner member satisfy the relationship 0.50 ≤ E'in(0°C) / E'in(-20°C) ≤ 0.95.

[0034] 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(0°C) of the outer material at 0°C can be set in the range of 10MPa to 14MPa, and the storage modulus E'in(0°C) of the inner material at 0°C can be set in the range of 9MPa to 130MPa. 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.

[0035] 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(0°C) and E'out(-20°C) of the outer member at 0°C and E'in(0°C) and E'in(-20°C) of the inner member at 0°C are set to satisfy the above-described relationship.

[0036] 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(0°C) at 0°C and the storage modulus E'out(-20°C) at -20°C satisfy the relationship 0.50 ≤ E'out(0°C) / E'out(-20°C) ≤ 0.95 for the rubber component with the largest storage modulus at 20°C, and among the rubber components located inside the transponder 20 in the tire width direction, the storage modulus E'in(0°C) at 0°C and the storage modulus E'in(-20°C) at -20°C satisfy the relationship 0.50 ≤ E'in(0°C) / E'in(-20°C) ≤ 0.95 for the rubber component with the largest storage modulus at 20°C. Therefore, in low-temperature environments, 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 makes it possible to improve tire durability while ensuring the durability of the transponder 20 in low-temperature environments.

[0037] Here, if the value of E'out(0℃) / E'out(-20℃) or E'in(0℃) / E'in(-20℃) 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 in low-temperature environments. Conversely, if the value of E'out(0℃) / E'out(-20℃) or E'in(0℃) / E'in(-20℃) is larger than the upper limit, the rate of change in the storage modulus between 0℃ and -20℃ is small, making the tire components brittle and leading to a decrease in tire durability.

[0038] In the above-described pneumatic tire, it is preferable that the storage modulus of elasticity E'out(-20°C) at -20°C and E'out(-40°C) of the outer material satisfy the relationship 0.4 ≤ E'out(-20°C) / E'out(-40°C) ≤ 0.7, and the storage modulus of elasticity E'in(-20°C) and E'in(-40°C) of the inner material satisfy the relationship 0.2 ≤ E'in(-20°C) / E'in(-40°C) ≤ 0.7. By appropriately setting the storage modulus of elasticity at low temperatures in this way, the durability of the tire in low-temperature environments can be effectively improved. Here, during driving, the temperature of the tire components rises due to heat generated by repeated deformation of the tire. If the temperature is less than the lower limit of the above relation (for example, the ratio of the storage modulus at -20°C to the storage modulus at -40°C is close to zero), the tire components are no longer brittle, and the tire's durability improves, but its durability at high speeds tends to deteriorate. For example, if the transponder 20 is covered with a rubber coating, the heat generated during high-speed driving softens the rubber coating, reducing its protective effect and easily degrading the durability of the transponder 20. On the other hand, if the temperature is greater than the upper limit of the above relation (for example, the ratio of the storage modulus at -20°C to the storage modulus at -40°C is close to 1.0), the tire components remain brittle, and the tire's durability tends to deteriorate.

[0039] Furthermore, 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 where the tire is at its 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 inward in the tire's radial direction 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 outward in the tire's radial direction 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 -20°C should ideally be in the range of 3 MPa to 17 MPa. By setting the physical properties of the coating layer 23 in this way, the durability of the transponder 20 in low-temperature environments can be effectively improved.

[0045] The storage modulus E'c(0°C) of the coating layer 23 at 0°C and the storage modulus E'c(-20°C) of the coating layer 23 at -20°C should satisfy the relationship 0.50 ≤ E'c(0°C) / E'c(-20°C) ≤ 0.95. 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), thereby effectively improving the durability of the transponder 20 in low-temperature environments. If the value is smaller than the lower limit of the above relationship, the rate of change in the storage modulus between 0°C and -20°C is large, which reduces the rigidity of the coating layer 23 and decreases its protective effect on the transponder 20. On the other hand, if the value is greater than the upper limit of the above relation, the rate of change in the storage modulus between 0°C and -20°C is excessively small. As a result, even when the tire generates heat, the rigidity of the coating layer 23 becomes higher than that of the surrounding rubber material, making the coating layer 23 more prone to rupture and reducing the protective effect of the coating layer 23 on the transponder 20.

[0046] Furthermore, it is preferable that the storage modulus E'c(0°C) of the coating layer 23 at 0°C and the storage modulus E'a(0°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 0°C satisfy the relationship 0.15 ≤ E'c(0°C) / E'a(0°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, thereby obtaining a stress distribution effect during driving and effectively improving the durability of the transponder 20 in low-temperature environments.

[0047] 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 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, thereby achieving a stress distribution effect during driving and effectively improving the durability of the transponder 20 in low-temperature environments.

[0048] 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).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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]

[0053] 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'out( Comparative Examples 1-4 and Examples 1-18 tires were manufactured with the following parameters set as shown in Tables 1 and 2: E'out(-20℃), E'in(0℃) / E'in(-20℃), E'out(-20℃) / E'out(-40℃), E'in(-20℃) / E'in(-40℃), 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(0℃), storage modulus of the coating layer E'c(-20℃), E'c(0℃) / E'a(0℃), E'c(-20℃) / E'a(-20℃), and E'c(0℃) / E'c(-20℃).

[0054] In Comparative Examples 1-4 and Examples 1-18, 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.

[0055] 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.

[0056] In Comparative Examples 2-4 and Examples 1-18, the outer component is the rim cushion rubber layer, and the inner component is the bead filler. In other words, in Tables 1 and 2, "E'out(0°C) / E'out(-20°C)" and "E'out(-20°C) / E'out(-40°C)" are the ratios of the storage modulus of the rim cushion rubber layer, which is the outer component, and "E'in(0°C) / E'in(-20°C)" and "E'in(-20°C) / E'in(-40°C)" are the ratios of the storage modulus of the bead filler, which is the inner component. Furthermore, "E'c(0°C) / E'a(0°C)" and "E'c(-20°C) / E'a(-20°C)" are the ratios 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(0℃) / E'c(-20℃)" 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 are shown as the physical properties of the outer member, and the physical properties of the bead filler are shown as the physical properties of the inner member.

[0057] 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.

[0058] 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 -20°C temperature, 120kPa air pressure, 102% of the maximum load, and a running speed of 81km / 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.

[0059] 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.

[0060] [Table 1]

[0061] [Table 2]

[0062] As can be seen from Tables 1 and 2, the pneumatic tires of Examples 1 to 18 showed a good balance of improved tire durability and transponder communication performance and durability compared to Comparative Example 2.

[0063] 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 Example 3, the value of E'in(0℃) / E'in(-20℃) was 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(0℃) / E'out(-20℃) and E'in(0℃) / E'in(-20℃) were set higher than the range specified in the present invention, resulting in poor tire durability. [Explanation of Symbols]

[0064] 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 0°C E'out(0°C) and the storage modulus at -20°C E'out(-20°C) of the rubber member located outside the transponder in the tire width direction with the largest storage modulus at 20°C satisfy the relationship 0.50 ≤ E'out(0°C) / E'out(-20°C) ≤ 0.95, and the storage modulus at 0°C E'i of the rubber member located inside the transponder in the tire width direction with the largest storage modulus at 20°C A pneumatic tire characterized in that the storage modulus E'in(-20°C) at n(0°C) and -20°C satisfies the relationship 0.50 ≤ E'in(0°C) / E'in(-20°C) ≤ 0.95, the storage modulus E'out(20°C) at 20°C of the rubber member with the largest storage modulus at 20°C among the rubber members located outside the transponder in the tire width direction is in the range of 8 MPa to 12 MPa, and the storage modulus E'in(20°C) at 20°C of the rubber member with the largest storage modulus at 20°C among the rubber members located inside the transponder in the tire width direction is in the range of 8 MPa to 110 MPa.

2. The pneumatic tire according to claim 1, characterized in that, 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 0.4 ≤ E'out(-20°C) / E'out(-40°C) ≤ 0.7 for the rubber member with the largest storage modulus at 20°C, and the storage modulus at -20°C E'in(-20°C) / E'in(-40°C) ≤ 0.7 for the rubber member located inward from the transponder in the tire width direction, the rubber member with the largest storage modulus at 20°C, satisfies the relationship 0.2 ≤ E'in(-20°C) / E'in(-40°C) ≤ 0.7 for the rubber member with the largest storage modulus at 20°C.

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(0°C) of the coating layer at 0°C and the storage modulus of elasticity E'a(0°C) of a rubber member adjacent to the outer side of the coating layer in the tire width direction satisfy the relationship 0.15 ≤ E'c(0°C) / E'a(0°C) ≤ 1.

30.

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 -20°C and the storage modulus of elasticity E'a(-20°C) of the rubber member adjacent to the outer side of the coating layer in the tire width direction satisfy the relationship 0.15 ≤ E'c(-20°C) / E'a(-20°C) ≤ 1.

30.

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 elasticity E'c (-20°C) of the coating layer is in the range of 3 MPa to 17 MPa.

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 storage modulus of the coating layer at 0°C E'c(0°C) and the storage modulus of the coating layer at -20°C E'c(-20°C) satisfy the relationship 0.50 ≤ E'c(0°C) / E'c(-20°C) ≤ 0.

95.

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

8. The pneumatic tire according to any one of claims 1 to 7, 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.

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

10. The pneumatic tire according to any one of claims 1 to 9, 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.

11. The pneumatic tire according to any one of claims 1 to 10, 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 position of the tire's maximum width.

12. The pneumatic tire according to any one of claims 1 to 11, 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.

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

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

15. 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 the storage modulus at 0°C E'out(0°C) and the storage modulus at -20°C E'out(-20°C) of the rubber member located outside the transponder in the tire width direction with the largest storage modulus at 20°C satisfies the relationship 0.50 ≤ E'out(0°C) / E'out(-20°C) ≤ 0.95, and the storage modulus at 0°C E of the rubber member located inside the transponder in the tire width direction with the largest storage modulus at 20°C A pneumatic tire characterized in that the storage modulus E'in(-20°C) at 0°C and -20°C satisfies the relationship 0.50 ≤ E'in(0°C) / E'in(-20°C) ≤ 0.95, the storage modulus E'out(20°C) at 20°C of the rubber member with the largest storage modulus at 20°C among the rubber members located outside the transponder in the tire width direction is in the range of 3 MPa to 5 MPa, and the storage modulus E'in(20°C) at 20°C of the rubber member with the largest storage modulus at 20°C among the rubber members located inside the transponder in the tire width direction is in the range of 5 MPa to 7 MPa.

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