Pneumatic tires

Abstract

The present invention provides a pneumatic tire capable of ensuring the communication and durability of a transponder and improving the durability of the tire. A transponder (20) is buried outside a carcass layer (4) in the tire width direction, and the transponder (20) is covered by a covering layer (23). The storage modulus E'c (20°C) of the covering layer (23) at 20°C and the storage modulus E'out (20°C) of a rubber member with the largest storage modulus at 20°C among the rubber members located outside the transponder (20) in the tire width direction satisfy the relationship of 0.1≤E'c (20°C) / E'out (20°C)≤1.5. In addition, the storage modulus E'c(20°C) of the coating layer (23) at 20°C and the storage modulus E'in(20°C) of the rubber component with the largest storage modulus at 20°C among the rubber components located on the inner side of the transponder (20) in the tire width direction satisfy the relationship of 0.03≤E'c(20°C) / E'in(20°C)≤1.50.

Description

Technical Field

[0001] The present invention relates to a pneumatic tire in which a transponder covered by a covering layer is embedded, and more particularly, to a pneumatic tire capable of improving the durability of the tire and the communication performance and durability of the transponder. Background Art

[0002] It is proposed to embed an RFID tag (transponder) in a pneumatic tire (for example, refer to Patent Document 1). When the transponder is embedded in the tire, there is the following problem: if the rigidity difference between the coating layer covering the transponder and the rubber components around the coating layer is large, it will cause stress concentration in these components due to tire deformation, resulting in damage to the transponder and deterioration of the durability of the tire. In addition, there is the following problem: if the transponder is arranged on the inner side of the carcass layer in the tire width direction, the radio wave is cut off by the tire components (for example, steel carcass, etc.) during the transponder communication, and the communication performance of the transponder is deteriorated.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 7-137510 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] An object of the present invention is to provide a pneumatic tire capable of improving the durability of the tire and improving the communication performance and durability of a transponder.

[0008] Technical means of solving problems

[0009] In order to achieve the above-mentioned purpose, the pneumatic tire of the first invention is characterized in that it comprises: a tread portion extending along the circumferential direction of the tire to form a ring shape; a pair of sidewall portions arranged on both sides of the tread portion; and a pair of bead portions arranged on the inner side of the sidewall portions in the radial direction of the tire, and a carcass layer is mounted between the pair of bead portions. In the pneumatic tire, a transponder is buried on the outside of the carcass layer in the tire width direction, and the transponder is covered by a covering layer. The storage modulus E'c(20℃) of the covering layer at 20℃ and the storage modulus E'out(20℃) of the rubber component with the largest storage modulus at 20℃ among the rubber components located on the outside of the transponder in the tire width direction satisfy the relationship of 0.1≤E'c(20℃) / E'out(20℃)≤1.5.

[0010] In addition, in order to achieve the above-mentioned purpose, the pneumatic tire of the second invention is characterized in that it comprises: a tread portion extending along the circumferential direction of the tire to form a ring shape; a pair of sidewall portions arranged on both sides of the tread portion; and a pair of bead portions arranged on the radial inner side of the sidewall portions, a carcass layer is mounted between the pair of bead portions, and in the pneumatic tire, a transponder is buried on the outside in the tire width direction of the carcass layer, the transponder is covered by a covering layer, and the storage modulus E'c(20℃) of the covering layer at 20℃ and the storage modulus E'in(20℃) at 20℃ of the rubber component with the largest storage modulus at 20℃ among the rubber components located on the inner side of the tire width direction of the transponder satisfy the relationship of 0.03≤E'c(20℃) / E'in(20℃)≤1.50.

[0011] Effects of the Invention

[0012] In the first invention, a transponder is buried outside the tire width direction relative to the carcass layer, so there is no tire component that cuts off the radio wave when the transponder communicates, and the communication performance of the transponder can be ensured. In addition, the transponder is covered by a covering layer, and the storage modulus E'c (20°C) of the covering layer at 20°C and the storage modulus E'out (20°C) of the rubber member with the largest storage modulus at 20°C among the rubber members located outside the tire width direction relative to the transponder satisfy the above-mentioned relationship, so the rigidity difference between the covering layer and the rubber member located outside the transponder is unlikely to become too large, so the rigidity of the covering layer relative to the rubber member can be appropriately ensured. As a result, the durability of the tire and the durability of the transponder can be improved.

[0013] In the second invention, a transponder is buried outside the tire width direction relative to the carcass layer, so there is no tire component that cuts off the radio wave when the transponder communicates, and the communication performance of the transponder can be ensured. In addition, the transponder is covered by a covering layer, and the storage modulus E'c (20°C) of the covering layer at 20°C and the storage modulus E'in (20°C) of the rubber member with the largest storage modulus at 20°C among the rubber members located inside the tire width direction relative to the transponder satisfy the above-mentioned relationship, so the rigidity difference between the covering layer and the rubber member located inside the transponder is unlikely to become too large, so the rigidity of the covering layer relative to the rubber member can be appropriately ensured. As a result, the durability of the tire and the durability of the transponder can be improved.

[0014] In the pneumatic tire of the first or second invention, preferably, the storage elastic modulus E'c(20°C) of the cover layer at 20°C is in the range of 2 MPa to 12 MPa. This can effectively improve the durability of the transponder.

[0015] Preferably, the relative dielectric constant of the coating layer is not more than 7. Thus, the radio wave transmittance of the transponder can be ensured, and the communication performance of the transponder can be effectively improved.

[0016] Preferably, the coating layer is composed of rubber or elastomer and 20 phr or more of white filler. Thus, the relative dielectric constant of the coating layer can be reduced, and the communication performance of the transponder can be effectively improved.

[0017] Preferably, the white filler contains 20 phr to 55 phr of calcium carbonate. This can reduce the relative dielectric constant of the coating layer and effectively improve the communication performance of the transponder.

[0018] Preferably, the center of the transponder is arranged to be separated from the joint of the tire component by 10 mm or more in the tire circumferential direction. This can effectively improve the durability of the tire.

[0019] Preferably, the transponder is arranged between a position 15 mm radially outward from the upper end of the bead core of the bead portion and the position of the maximum width of the tire. Thus, the transponder is arranged in an area with low stress amplitude during driving, thereby effectively improving the durability of the transponder.

[0020] Preferably, the distance between the cross-sectional center of the transponder and the outer surface of the tire is 2 mm or more. This can effectively improve the durability of the tire and improve the resistance to external damage of the tire.

[0021] Preferably, the coating layer has a thickness of 0.5 mm to 3.0 mm. This prevents the outer surface of the tire from being uneven, and effectively improves the communication performance of the transponder.

[0022] Preferably, the transponder has an IC substrate for storing data and an antenna for transmitting and receiving data, and the antenna is spiral-shaped. Thus, the deformation of the tire during driving can be tracked, and the durability of the transponder can be improved.

[0023] In the first and second inventions, the storage modulus E' is measured in accordance with JIS-K6394 using a viscoelasticity spectrometer in a tensile deformation mode under the conditions of specified temperatures, frequency 10 Hz, initial strain 10%, and dynamic strain ±2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a meridian half cross-sectional view showing a pneumatic tire according to an embodiment of the present invention.

[0025] Figure 2 It roughly indicates Figure 1 Meridian cross-section view of a pneumatic tire.

[0026] Figure 3 It roughly indicates Figure 1 Equatorial cross-sectional view of a pneumatic tire.

[0027] Figure 4 It is an enlarged view of the buried Figure 1 Cross-sectional view of a transponder of a pneumatic tire.

[0028] Figure 5 (a) Figure 5 (b) is a perspective view showing a transponder that can be embedded in the pneumatic tire of the present invention.

[0029] Figure 6 It is an explanatory diagram showing the tire radial position of the transponder in the test tire. DETAILED DESCRIPTION

[0030] Hereinafter, the configuration of the first invention will be described in detail with reference to the drawings. Figure 1 to Figure 4 It is a figure which shows the pneumatic tire comprised by embodiment of this invention.

[0031] like Figure 1 As shown, the pneumatic tire of this embodiment includes a tread portion 1 extending in a ring shape in the tire circumferential direction, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged on the inner side of the sidewall portions 2 in the tire radial direction.

[0032] Between the pair of bead portions 3, at least one layer (in Figure 1 The tire body layer 4 is a layer in the middle. The tire body layer 4 is covered with rubber. As the tire body cord constituting the tire body layer 4, it is preferable to use an organic fiber cord such as nylon or polyester. An annular bead core 5 is embedded in each bead portion 3, and a bead core 6 made of a rubber composition with a triangular cross section is arranged on the outer periphery of the bead core 5.

[0033] On the other hand, a plurality of layers (in the tire outer peripheral side of the carcass layer 4 of the tread portion 1) are buried. Figure 1 The belt layer 7 includes a plurality of reinforcing cords inclined relative to the tire circumferential direction, and the reinforcing cords are arranged to cross each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cords relative to the tire circumferential direction is set in the range of 10° to 40°, for example. As the reinforcing cords of the belt layer 7, steel cords are preferably used.

[0034] In order to improve high-speed durability, at least one layer (in the tire outer peripheral side of the belt layer 7) in which reinforcing cords are arranged at an angle of, for example, 5° or less relative to the tire circumferential direction is arranged. Figure 1 In the middle two layers) belt covering layer 8. Figure 1The belt covering layer 8 located on the inner side in the tire radial direction constitutes a full covering member covering the entire width of the belt layer 7, and the belt covering layer 8 located on the outer side in the tire radial direction constitutes an edge covering layer covering only the end of the belt layer 7. As the reinforcing cords of the belt covering layer 8, organic fiber cords such as nylon and aramid are preferably used.

[0035] In the above-mentioned pneumatic tire, the two ends 4e of the carcass layer 4 are configured to be folded back from the inner side to the outer side of the tire around each bead core 5, and wrap the bead core 5 and the bead core 6. The carcass layer 4 includes: a main body portion 4A, which is a portion extending from the tread portion 1 through each sidewall portion 2 to each bead portion 3; and a turned-up portion 4B, which is a portion turned up around the bead core 5 in each bead portion 3 and extending toward the side of each sidewall portion 2.

[0036] In addition, an inner liner 9 is disposed on the inner surface of the tire along the carcass layer 4 . A cap rubber layer 11 is disposed in the tread portion 1 , a sidewall rubber layer 12 is disposed in the sidewall portion 2 , and a rim cushion rubber layer 13 is disposed in the bead portion 3 .

[0037] In addition, in the above-mentioned pneumatic tire, a transponder 20 is embedded in a portion outside the tire width direction relative to the carcass layer 4. The transponder 20 extends along the tire circumferential direction. The transponder 20 may also be arranged to be inclined in the range of -10° to 10° relative to the tire circumferential direction. Figure 4 As shown, the transponder 20 is covered by a covering layer 23. The covering layer 23 covers the entire transponder 20 in a manner of sandwiching both the front and back sides of the transponder 20. The covering layer 23 may be made of a rubber having the same physical properties as the rubber constituting the sidewall rubber layer 12 or the rim buffer rubber layer 13, or may be made of a rubber having different physical properties therefrom.

[0038] As the transponder 20, for example, an RFID (Radio Frequency Identification) tag can be used. Figure 5 (a) Figure 5 As shown in (b), the transponder 20 has an IC substrate 21 for storing data and an antenna 22 for non-contact data transmission and reception. By using such a transponder 20, information related to the tire can be written or read in a timely manner, and the tire can be managed efficiently. It should be noted that RFID refers to an automatic identification technology that can communicate data wirelessly, consisting of a reader / writer having an antenna and a controller and an ID tag having an IC substrate and an antenna.

[0039] The overall shape of the transponder 20 is not particularly limited. Figure 5 (a) Figure 5 As shown in (b), columnar or plate-shaped transponders can be used. Figure 5In the case of the columnar transponder 20 shown in (a), it is possible to track the deformation of the tire in all directions, so it is preferred. In this case, the antenna 22 of the transponder 20 protrudes from both ends of the IC substrate 21 and is spiral. As a result, it is possible to track the deformation of the tire during driving, and the durability of the transponder 20 can be improved. In addition, by appropriately changing the length of the antenna 22, communication performance can be ensured.

[0040] In the pneumatic tire configured as above, the rubber member located on the outer side in the tire width direction relative to the transponder 20 (in Figure 1 The rubber member (hereinafter also referred to as an outer member) having the largest storage modulus E'out (20°C) at 20°C among the sidewall rubber layer 12 and the rim cushion rubber layer 13 corresponds to the rim cushion rubber layer 13. It should be noted that the rubber member (outer member) having the largest storage modulus at 20°C does not include the covering layer 23 covering the transponder 20.

[0041] Here, the storage modulus E'out(20°C) of the outer member at 20°C and the storage modulus E'c(20°C) of the coating layer 23 at 20°C satisfy the relationship of 0.1≤E'c(20°C) / E'out(20°C)≤1.5. In particular, it is preferable to satisfy the relationship of 0.15≤E'c(20°C) / E'out(20°C)≤1.30.

[0042] It should be noted that in Figure 1 In the embodiment of the present invention, an example is shown in which the transponder 20 is arranged between the turned-up portion 4B of the carcass layer 4 and the rim buffer rubber layer 13, but the present invention is not limited to this. In addition, the transponder 20 can be arranged between the main body 4A of the carcass layer 4 and the sidewall rubber layer 12. The outer member changes according to the arrangement position of the transponder 20, but in any case, the storage modulus E'c (20°C) of the covering layer 23 at 20°C and the storage modulus E'out (20°C) of the outer member at 20°C are set to satisfy the above relationship.

[0043] In the above-mentioned pneumatic tire, the transponder 20 is buried outside the carcass layer 4 in the tire width direction. Therefore, there is no tire component that cuts off the radio wave when the transponder 20 communicates, and the communication performance of the transponder 20 can be ensured. In addition, the transponder 20 is covered by the covering layer 23, and the storage modulus E'c (20°C) of the covering layer 23 at 20°C and the storage modulus E'out (20°C) of the rubber member with the largest storage modulus at 20°C among the rubber members located outside the transponder 20 in the tire width direction satisfy the relationship of 0.1≤E'c (20°C) / E'out (20°C)≤1.5. Therefore, the difference in rigidity between the covering layer 23 and the rubber member located outside the transponder 20 is unlikely to become too large, and therefore, the rigidity of the covering layer 23 relative to the rubber member can be appropriately ensured. As a result, the durability of the tire and the durability of the transponder 20 can be improved.

[0044] Here, when the value of E'c(20°C) / E'out(20°C) is less than the lower limit, the cover layer 23 is too soft compared to the outer member, so when the outer member is bent with tire deformation, the cover layer 23 is compressed, and the transponder 20 becomes easily damaged. On the contrary, when the value of E'c(20°C) / E'out(20°C) is greater than the upper limit, stress concentration occurs at the end of the cover layer 23 when the tire is deformed, and due to repeated shear deformation, peeling is easily generated at the interface between the cover layer 23 and the rubber member adjacent to the cover layer 23.

[0045] It should be noted that the rubber member located on the inner side of the transponder 20 in the tire width direction (in Figure 1Among the coating rubber of the carcass layer 4, the bead core 6 and the inner liner 9, the rubber member (inner member) having the largest storage modulus E'in (20°C) at 20°C corresponds to the bead core 6. The physical properties of the inner member and the physical properties of the outer member improve the protection of the transponder 20 against deformation of the tire during driving, and therefore, preferably satisfy the relationship of 0.01×E'c (20°C) / E'out (20°C)≤E'c (20°C) / E'in (20°C)≤7.5×E'c (20°C) / E'out (20°C). In particular, when the JIS hardness (20°C) of the inner member is high, it is preferable to satisfy the relationship of 0.01×E'c(20°C) / E'out(20°C)≤E'c(20°C) / E'in(20°C)≤1.2×E'c(20°C) / E'out(20°C), and it is more preferable to satisfy the relationship of 0.01×E'c(20°C) / E'out(20°C)≤E'c(20°C) / E'in(20°C)≤1.0×E'c(20°C) / E'out(20°C). In this case, the deformation is small, which is effective in preventing the transponder 20 from being damaged. In addition, when the JIS hardness (20°C) of the inner member is low, it is better to satisfy the relationship of 0.6×E'c(20°C) / E'out(20°C)≤E'c(20°C) / E'in(20°C)≤7.5×E'c(20°C) / E'out(20°C), and it is even better to satisfy the relationship of 0.6×E'c(20°C) / E'out(20°C)≤E'c(20°C) / E'in(20°C)≤6.5×E'c(20°C) / E'out(20°C). In this case, stress concentration is less likely to occur, which is also effective in improving the durability of the tire. It should be noted that the rubber member (inner member) having the largest storage modulus at 20°C does not include the coating layer 23 that covers the transponder 20.

[0046] In the pneumatic tire, the storage elastic modulus E′c (20° C.) of the cover layer 23 at 20° C. is preferably in the range of 2 MPa to 12 MPa. By setting the physical properties of the cover layer 23 in this way, the durability of the transponder 20 can be effectively improved.

[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'c(60°C) of the coating layer 23 at 60°C satisfy the relationship of 1.0≤E'c(20°C) / E'c(60°C)≤1.5.

[0048] By setting the physical properties of the coating layer 23 in this way, the temperature dependence of the coating layer 23 becomes lower (the coating layer 23 becomes difficult to generate heat). Therefore, even if the temperature of the tire rises during high-speed driving, the coating layer 23 will not soften, which can effectively improve the durability of the transponder 20.

[0049] The storage modulus E'c (60°C) of the cover layer 23 at 60°C is similar to that of the rubber member (at the outer side of the cover layer 23 in the tire width direction). Figure 4 The storage modulus E'a (60°C) of the rim cushion rubber layer 13 at 60°C preferably satisfies the relationship of 0.2≤E'c (60°C) / E'a (60°C)≤1.2. By setting the physical properties of the covering layer 23 and the rubber member adjacent to the covering layer 23 in this way, the physical properties of the two are close, so that the stress dispersion effect during driving can be obtained, and the durability of the transponder 20 can be effectively improved.

[0050] As a component of the coating layer 23, it is preferred that the coating layer 23 is composed of rubber or elastomer and 20 phr or more of white filler. By constituting the coating layer 23 in this way, the relative dielectric constant of the coating layer 23 can be lower than that of the case where carbon is contained, and the communication performance of the transponder 20 can be effectively improved. It should be noted that in this specification, "phr" refers to the weight part per 100 parts by weight of the rubber component (elastomer).

[0051] Preferably, the white filler constituting the coating layer 23 contains 20 phr to 55 phr of calcium carbonate. As a result, the relative dielectric constant of the coating layer 23 can be made lower, which can effectively improve the communication performance of the transponder 20. However, if the white filler contains excessive calcium carbonate, it will become brittle, which is not preferred because the strength of the coating layer 23 is reduced. In addition, in addition to calcium carbonate, the coating layer 23 can arbitrarily contain less than 20 phr of silica (white filler) and less than 5 phr of carbon black. When a small amount of silica and carbon black are used in combination, the strength of the coating layer 23 can be ensured and its relative dielectric constant can be reduced.

[0052] In addition, the relative dielectric constant of the coating layer 23 is preferably less than 7, and more preferably 2 to 5. By appropriately setting the relative dielectric constant of the coating layer 23 in this way, the radio wave transmittance when the transponder 20 transmits radio waves can be ensured, and the communication performance of the transponder 20 can be effectively improved. It should be noted that the relative dielectric constant of the rubber constituting the coating layer 23 is a relative dielectric constant of 860MHz to 960MHz at room temperature. Here, the room temperature is 23±2°C and 60%±5%RH according to the standard state of the JIS specification. The relative dielectric constant of the rubber is measured by the electrostatic capacitance method after being treated at 23°C and 60%RH for 24 hours. The above-mentioned range of 860MHz to 960MHz is consistent with the current state of the allocated frequency of the ultra-high (UHF: Ultra High Frequency) band RFID, but in the case of changing the above-mentioned allocated frequency, as long as the relative dielectric constant of the range of its allocated frequency is as specified above.

[0053] The thickness t of the coating layer 23 is preferably 0.5 mm to 3.0 mm, more preferably 1.0 mm to 2.5 mm. Here, the thickness t of the coating layer 23 is the thickness of the rubber at the position including the transponder 20, for example, Figure 4 As shown, it is the rubber thickness which is the sum of the thickness t1 and the thickness t2 on the straight line which passes through the center of the transponder 20 and is perpendicular to the outer surface of the tire. By appropriately setting the thickness t of the coating layer 23 in this way, it is possible to effectively improve the communication performance of the transponder 20 without causing bumps on the outer surface of the tire. Here, when the thickness t of the coating layer 23 is thinner than 0.5 mm, the improvement effect of the communication performance of the transponder 20 cannot be obtained. On the contrary, when the thickness t of the coating layer 23 exceeds 3.0 mm, bumps are caused on the outer surface of the tire, which is not preferred in appearance. It should be noted that the cross-sectional shape of the coating layer 23 is not particularly limited, but, for example, a triangle, a rectangle, a trapezoid, or a spindle shape may be used. Figure 4 The cladding layer 23 has a substantially spindle-shaped cross-sectional shape.

[0054] In the above-mentioned pneumatic tire, as the tire radial configuration area, the transponder 20 is preferably configured between a position P1 15 mm from the upper end 5e of the bead core 5 (the end on the outer side of the tire radial direction) to the outer side of the tire radial direction and a position P2 which is the maximum width of the tire. Figure 2 The area S1 shown is good. When the transponder 20 is arranged in the area S1, the transponder 20 is located in an area where the stress amplitude during driving is small, so the durability of the transponder 20 can be effectively improved, and the durability of the tire will not be reduced. Here, when the transponder 20 is arranged radially inward of the tire compared to the position P1, it becomes close to metal components such as the bead core 5, and therefore, there is a tendency for the communication performance of the transponder 20 to deteriorate. On the other hand, when the transponder 20 is arranged radially outward of the tire compared to the position P2, the transponder 20 is located in an area where the stress amplitude during driving is large, and it is easy to cause damage to the transponder 20 itself and interface peeling around the transponder 20, so it is not preferred.

[0055] like Figure 3 As shown, on the circumference of the tire, there are a plurality of joint portions formed by overlapping end portions of tire constituent members. Figure 3 The position Q of each joint portion in the tire circumferential direction is shown in FIG. Preferably, the center of the transponder 20 is arranged to be separated from the joint portion of the tire component by more than 10 mm in the tire circumferential direction. Figure 3The area S2 shown is preferred. Specifically, the IC substrate 21 constituting the transponder 20 is preferably separated from the position Q in the tire circumferential direction by more than 10 mm. Moreover, it is more preferred that the transponder 20 including the antenna 22 is separated from the position Q in the tire circumferential direction by more than 10 mm as a whole, and it is most preferred that the transponder 20 in a state covered by the covering rubber is separated from the position Q in the tire circumferential direction by more than 10 mm as a whole. In addition, as a tire component configured separately from the transponder 20, the sidewall rubber layer 12 or the rim buffer rubber layer 13, or the carcass layer 4 configured adjacent to the transponder 20 is preferred. By configuring the transponder 20 in a manner separated from the joint portion of the tire component in this way, the durability of the tire can be effectively improved.

[0056] It should be noted that in Figure 3 In the embodiment of the invention, an example is shown in which the positions Q of the joints of the tire components in the tire circumferential direction are arranged at equal intervals, but the invention is not limited thereto. The positions Q in the tire circumferential direction can be set at any position, and in any case, the transponders 20 are arranged to be separated from the joints of the tire components by more than 10 mm in the tire circumferential direction.

[0057] like Figure 4 As shown, it is preferable that the distance d between the cross-sectional center of the transponder 20 and the tire outer surface is 2 mm or more. By separating the transponder 20 from the tire outer surface in this way, the durability of the tire can be effectively improved, and the resistance to external damage of the tire can be improved.

[0058] In the above-mentioned embodiment, an example is shown in which the end 4e of the turned-up portion 4B of the carcass layer 4 is arranged near the upper end 6e of the bead core 6, but it is not limited to this, and the end 4e of the turned-up portion 4B of the carcass layer 4 can be arranged at any height. For example, the end 4e of the turned-up portion 4B of the carcass layer 4 can be arranged on the side of the bead core 5. In such a low-folded structure (Low-TU), the transponder 20 can also be arranged between the bead core 6 and the sidewall rubber layer 12 or the rim buffer 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 buffer rubber layer 13.

[0059] Next, the structure of the second invention will be described. The pneumatic tire of the second invention has the following features in the same manner as the first invention: Figure 1 to Figure 5 (a) Figure 5 The tire structure as shown in (b).

[0060] In the pneumatic tire of the second invention, the rubber member located on the inner side of the transponder 20 in the tire width direction (in Figure 1The rubber component (hereinafter also referred to as the inner component) having the largest storage modulus E'in (20°C) at 20°C among the coating rubber of the carcass layer 4, the bead core 6 and the inner liner 9 corresponds to the bead core 6. It should be noted that the rubber component (inner component) having the largest storage modulus at 20°C does not include the covering layer 23 covering the transponder 20.

[0061] Here, the storage modulus E'in(20°C) of the inner member at 20°C and the storage modulus E'c(20°C) of the coating layer 23 at 20°C satisfy the relationship of 0.03≤E'c(20°C) / E'in(20°C)≤1.50. In particular, it is preferred that the relationship of 0.15≤E'c(20°C) / E'in(20°C)≤1.30 be satisfied.

[0062] It should be noted that in Figure 1 In the embodiment of the present invention, an example is shown in which the transponder 20 is arranged between the turned-up portion 4B of the carcass layer 4 and the rim buffer rubber layer 13, but the present invention is not limited to this. In addition, the transponder 20 can be arranged between the main body 4A of the carcass layer 4 and the sidewall rubber layer 12. The inner member changes according to the arrangement position of the transponder 20, but in any case, the storage modulus E'c (20°C) of the covering layer 23 at 20°C and the storage modulus E'in (20°C) of the inner member at 20°C are set to satisfy the above relationship.

[0063] In the above-mentioned pneumatic tire, the transponder 20 is buried outside the carcass layer 4 in the tire width direction. Therefore, there is no tire component that cuts off the radio wave when the transponder 20 communicates, and the communication performance of the transponder 20 can be ensured. In addition, the transponder 20 is covered by the covering layer 23, and the storage modulus E'c (20°C) of the covering layer 23 at 20°C and the storage modulus E'in (20°C) of the rubber member with the largest storage modulus at 20°C among the rubber members located inside the transponder 20 in the tire width direction satisfy the relationship of 0.03≤E'c (20°C) / E'in (20°C)≤1.50. Therefore, the difference in rigidity between the covering layer 23 and the rubber member located inside the transponder 20 is unlikely to become too large, and therefore, the rigidity of the covering layer 23 relative to the rubber member can be appropriately ensured. As a result, the durability of the tire and the durability of the transponder 20 can be improved.

[0064] Here, when the value of E'c (20°C) / E'in (20°C) is less than the lower limit, the inner member is harder than the covering layer 23, so the inner member is difficult to deform, and since the covering layer 23 is soft, the protective effect on the transponder 20 is reduced, and the transponder 20 becomes easy to be damaged. On the contrary, when the value of E'c (20°C) / E'in (20°C) is greater than the upper limit, stress concentration is likely to occur at the end of the covering layer 23 when the tire is deformed, and peeling is likely to occur at the interface between the covering layer 23 and the rubber member adjacent to the covering layer 23.

[0065] It should be noted that the rubber member located on the outside of the transponder 20 in the tire width direction ( Figure 1 The rubber member (external member) having the largest storage modulus E'out (20°C) at 20°C among the sidewall rubber layer 12 and the rim cushion rubber layer 13 corresponds to the rim cushion rubber layer 13. The physical properties of the external member and the physical properties of the internal member can improve the protection of the transponder 20 against tire deformation during driving, and therefore, preferably, the relationship of 0.1×E'c (20°C) / E'in (20°C)≤E'c (20°C) / E'out (20°C)≤75.0×E'c (20°C) / E'in (20°C) is satisfied. In particular, when the JIS hardness (20°C) of the inner member is high, it is preferable to satisfy the relationship of 0.8×E'c(20°C) / E'in(20°C)≤E'c(20°C) / E'out(20°C)≤75.0×E'c(20°C) / E'in(20°C), and it is more preferable to satisfy the relationship of 0.95×E'c(20°C) / E'in(20°C)≤E'c(20°C) / E'out(20°C)≤64.0×E'c(20°C) / E'in(20°C). In this case, deformation is small, which is effective in preventing damage to the transponder 20. In addition, when the JIS hardness (20°C) of the inner member is low, it is better to satisfy the relationship of 0.1×E'c(20°C) / E'in(20°C)≤E'c(20°C) / E'out(20°C)≤40.0×E'c(20°C) / E'in(20°C), and it is better to satisfy the relationship of 0.15×E'c(20°C) / E'in(20°C)≤E'c(20°C) / E'out(20°C)≤37.5×E'c(20°C) / E'in(20°C). In this case, stress concentration is less likely to occur, and it is also effective in improving the durability of the tire. It should be noted that the rubber member (external member) having the largest storage modulus at 20°C does not include the coating layer 23 that covers the transponder 20.

[0066] Example

[0067] The following tires of Comparative Examples 1 to 3 and Examples 1 to 11 were produced: in a tire size of 265 / 40ZR20, the tire has a tread portion extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged on the radial inner side of the sidewall portions, a transponder is buried in an inflatable tire with a carcass layer mounted between the pair of bead portions, and the transponder is covered by a covering layer. The position of the transponder in the tire width direction, the position of the transponder in the tire radial direction, E'c (20°C) / E'out (20°C), the relative dielectric constant of the covering layer, the thickness of the covering layer, and the storage modulus E'c (20°C) of the covering layer are set as shown in Table 1.

[0068] In Comparative Examples 1 to 3 and Examples 1 to 11, a columnar transponder is used, the distance from the center of the transponder to the joint of the tire components in the tire circumferential direction is set to 10 mm, and the distance from the cross-sectional center of the transponder to the tire outer surface is set to 2 mm or more.

[0069] In Table 1, when the position of the transponder in the tire width direction is "inside", it means that the transponder is arranged on the inside of the tire width direction of the carcass layer, and when the position of the transponder in the tire width direction is "outside", it means that the transponder is arranged on the outside of the tire width direction of the carcass layer. In addition, in Table 1, the positions of the transponders in the tire radial direction are respectively Figure 6 The positions A to E shown correspond.

[0070] In Comparative Examples 2 and 3 and Examples 1 to 11, the outer member is a rim cushion rubber layer. That is, in Table 1, "E'c (20°C) / E'out (20°C)" is the ratio of the storage modulus of the coating layer to the storage modulus of the rim cushion rubber layer as the outer member. In Comparative Example 1, for convenience, the physical properties of the rim cushion rubber layer are shown as the physical properties of the outer member.

[0071] With respect to these test tires, tire evaluation (durability) and transponder evaluation (communication performance and durability) were performed by the following test methods, and the results are collectively shown in Table 1.

[0072] Durability (tires and transponders):

[0073] Each test tire is assembled on a wheel with a standard rim, and a driving test is carried out using a drum tester under the conditions of an air pressure of 120 kPa, 102% of the maximum load, and a driving speed of 81 km. The driving distance when the tire fails is measured. The evaluation results are expressed by setting the comparative example 2 as an index of 100. The larger the index value, the better the durability of the tire. In addition, for each test tire after the driving, it is confirmed whether the transponder can communicate and whether there is any damage. The three stages are shown as "◎ (excellent)" for the case where communication is possible and there is no damage, "○ (good)" for the case where communication is possible but there is damage, and "× (unable)" for the case where communication is not possible.

[0074] Communication (responder):

[0075] For each test tire, a reader / writer was used to perform communication with the transponder. Specifically, the longest distance that can be communicated with the reader / writer was measured at an output of 250 mW and a carrier frequency of 860 MHz to 960 MHz. The evaluation results are indicated by indices with Comparative Example 2 being 100.

[0076] The larger the index value, the better the communication performance.

[0077]

[0078] As can be seen from Table 1, the pneumatic tires of Examples 1 to 11 have improved tire durability and transponder communication performance and durability in a well-balanced manner compared to Comparative Example 2.

[0079] On the other hand, in Comparative Example 1, the transponder is arranged inside the carcass layer in the tire width direction, so the communication performance of the transponder is deteriorated. In Comparative Example 3, the value of E'c(20°C) / E'out(20°C) is set higher than the range specified in the first invention, so the durability of the tire is deteriorated.

[0080] Next, the following tires of Comparative Examples 21 to 23 and Examples 21 to 31 were produced: in a tire size of 265 / 40ZR20, the tire has a tread portion extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged on the radial inner side of the sidewall portions, and a transponder is embedded in an inflatable tire with a carcass layer mounted between the pair of bead portions. The transponder is covered by a covering layer, and the position of the transponder in the tire width direction, the radial position of the transponder in the tire, E'c (20°C) / E'in (20°C), the relative dielectric constant of the covering layer, the thickness of the covering layer, and the storage modulus E'c (20°C) of the covering layer are set as shown in Table 2.

[0081] In Comparative Examples 21 to 23 and Examples 21 to 31, a columnar transponder is used, the distance from the center of the transponder to the joint of the tire constituent member in the tire circumferential direction is set to 10 mm, and the distance from the cross-sectional center of the transponder to the outer surface of the tire is set to greater than 2 mm.

[0082] In Table 2, when the position of the transponder in the tire width direction is "inside", it means that the transponder is arranged on the inside of the tire width direction of the carcass layer, and when the position of the transponder in the tire width direction is "outside", it means that the transponder is arranged on the outside of the tire width direction of the carcass layer. In addition, in Table 2, the positions of the transponders in the tire radial direction are respectively Figure 6 The positions A to E shown correspond.

[0083] In Comparative Examples 22 and 23 and Examples 21 to 31, the inner member is a bead core. That is, in Table 2, "E'c (20°C) / E'in (20°C)" is the ratio of the storage modulus of the coating layer to the storage modulus of the bead core as the inner member. In Comparative Example 21, for convenience, the physical properties of the bead core are shown as the physical properties of the inner member.

[0084] These test tires were subjected to tire evaluation (durability) and transponder evaluation (communication performance and durability) by the following test methods, and the results are shown in Table 2.

[0085]

[0086] As can be seen from Table 2, the pneumatic tires of Examples 21 to 31 have improved tire durability and transponder communication performance and durability in a well-balanced manner compared to Comparative Example 22.

[0087] On the other hand, in Comparative Example 21, the transponder is arranged inside the carcass layer in the tire width direction, so the communication performance of the transponder is deteriorated. In Comparative Example 23, the value of E'c(20°C) / E'in(20°C) is set higher than the range specified in the second invention, so the durability of the tire is deteriorated.

[0088] Description of Reference Numerals

[0089] 1 Tread

[0090] 2 Side wall

[0091] 3 Bead section

[0092] 4 Carcass layer

[0093] 5 Bead core

[0094] 6 Bead core

[0095] 7 Belt

[0096] 12 Sidewall rubber layer

[0097] 13 Rim cushion rubber layer

[0098] 20 Transponder

[0099] 23 Coating

[0100] CL Tire Center Line

Claims

1. A pneumatic tire, characterized in that: The pneumatic tire comprises: a tread portion extending in a circumferential direction of the tire to form an annular shape; a pair of sidewall portions arranged on both sides of the tread portion; and a pair of bead portions arranged on the inner side of the sidewall portion in the tire radial direction, a carcass layer is mounted between the pair of bead portions, and a sidewall rubber layer and a rim cushion rubber layer are arranged on the outer side of the carcass layer on the sidewall portion. In the pneumatic tire, A transponder is buried on the outside of the carcass layer in the tire width direction, the transponder is covered by a covering layer, the covering layer is made of rubber, the storage modulus E'c (20°C) of the covering layer at 20°C and the storage modulus E'out (20°C) of the rubber component with the largest storage modulus at 20°C among the rubber components located on the outside of the transponder in the tire width direction satisfy the relationship of 0.1≤E'c (20°C) / E'out (20°C)≤0.8, the storage modulus E'c (20°C) of the covering layer at 20°C and the storage modulus E'c (60°C) of the covering layer at 60°C satisfy the relationship of 1.0≤E'c (20°C) / E'c (60°C)≤1.5, The center of the transponder is arranged to be separated by 10 mm or more in the tire circumferential direction from a joint portion of any one of the sidewall rubber layer, the rim cushion rubber layer, and the carcass layer.

2. The pneumatic tire according to claim 1, characterized in that The storage modulus E'c(20°C) of the covering layer at 20°C and the storage modulus E'in(20°C) of the rubber member with the largest storage modulus at 20°C among the rubber members located on the inner side of the transponder in the tire width direction satisfy the relationship of 0.03≤E'c(20°C) / E'in(20°C)≤1.

50.

3. The pneumatic tire according to claim 1 or 2, characterized in that: The storage modulus E′c (20° C.) of the coating layer at 20° C. is in the range of 2 MPa to 12 MPa.

4. The pneumatic tire according to claim 1 or 2, characterized in that: The relative dielectric constant of the coating layer is 7 or less.

5. The pneumatic tire according to claim 1 or 2, characterized in that: The coating layer is composed of rubber or elastomer and more than 20 phr of white filler.

6. The pneumatic tire according to claim 5, characterized in that: The white filler contains 20 phr to 55 phr of calcium carbonate.

7. The pneumatic tire according to claim 1, 2 or 6, characterized in that: The transponder is disposed between a position 15 mm outward in the tire radial direction from an upper end of a bead core of the bead portion and a position of maximum tire width.

8. The pneumatic tire according to claim 1, 2 or 6, characterized in that: The distance between the cross-sectional center of the transponder and the outer surface of the tire is greater than 2 mm.

9. The pneumatic tire according to claim 1, 2 or 6, characterized in that: The coating layer has a thickness of 0.5 mm to 3.0 mm.

10. The pneumatic tire according to claim 1, 2 or 6, characterized in that: The transponder includes an IC substrate for storing data and an antenna for transmitting and receiving data, and the antenna is spiral-shaped.

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