JP2021127087A - Pneumatic tire - Google Patents

Abstract

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

Description

The present invention relates to a pneumatic tire in which a transponder is embedded, and more particularly to a pneumatic tire capable of improving the durability of the tire while ensuring the communication and durability of the transponder.

In a pneumatic tire, it has been proposed to embed an RFID tag (transponder) in the tire (see, for example, Patent Document 1). When the transponder is embedded in the tire, there is a problem that the durability of the tire deteriorates when the tire generates heat during high-speed running and the rubber member around the transponder softens. Further, when the transponder is arranged inside the carcass layer in the tire width direction, radio waves are blocked by tire components (for example, metal members such as carcass made of steel and reinforcement) during communication of the transponder, and the communication property of the transponder deteriorates. Sometimes. Further, depending on the physical properties of the rubber member adjacent to the inside or outside of the transponder in the tire width direction, stress concentration may occur when the tire is deformed, and the durability of the transponder may be deteriorated.

Japanese Unexamined Patent Publication No. 7-137510

An object of the present invention is to provide a pneumatic tire capable of improving the durability of a tire while ensuring the communicability and durability of a transponder.

The pneumatic tire of the present invention for achieving the above object has a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and these sidewall portions. In a pneumatic tire having a pair of bead portions arranged inside in the tire radial direction and a carcass layer mounted between the pair of bead portions, a transponder is embedded outside the carcass layer in the tire width direction. Among the rubber members located outside the tire width direction from the transponder, the rubber member having the largest storage elasticity at 20 ° C. has a storage elasticity E'out (50 ° C.) of 50 ° C. and a storage elasticity E'out (50 ° C.) of 150 ° C. 150 ° C.) satisfies the relationship of 1.0 ≦ E'out (50 ° C.) / E'out (150 ° C.) ≦ 2.0, and is stored at 20 ° C. among the rubber members located inside the tire width direction from the transponder. The storage elastic coefficient E'in (50 ° C.) at 50 ° C. and the storage elastic coefficient E'in (150 ° C.) at 150 ° C. in the rubber member having the highest elastic coefficient are 1.0 ≦ E'in (50 ° C.) / E'. It is characterized in that the relationship of in (150 ° C.) ≤ 4.0 is satisfied.

In the present invention, since the transponder is embedded outside the carcass layer in the tire width direction, there is no tire component that blocks radio waves during communication of the transponder, and the communicability of the transponder can be ensured. Further, among the rubber members located outside the transponder in the tire width direction, the rubber member having the largest storage elastic modulus at 20 ° C. has a storage elastic modulus E'out (50 ° C.) of 50 ° C. and a storage elastic modulus E'out of 150 ° C. (150 ° C) and 50 ° C storage elastic modulus E'in (50 ° C) and 150 ° C storage elastic modulus of the rubber member having the largest storage elastic modulus at 20 ° C among the rubber members located inside the transponder in the tire width direction. Since the modulus E'in (150 ° C.) satisfies the above relational expression, the rigidity of the rubber members located inside and outside the transponder is maintained even when the temperature of the tire becomes high, and sufficient strength can be ensured. At the same time, stress concentration at the time of tire deformation can be suppressed. As a result, the durability of the tire can be improved while ensuring the durability of the transponder.

In the pneumatic tire of the present invention, the transponder is coated with a coating layer, and the storage elastic modulus E'c (20 ° C.) of the coating layer at 20 ° C. and the rubber member 20 ° C. adjacent to the outer side of the coating layer in the tire width direction It is preferable that the storage elastic modulus E'a (20 ° C.) satisfies the relationship of 0.1 ≦ E'c (20 ° C.) / E'a (20 ° C.) ≦ 1.5. As a result, the physical properties of the coating layer and the rubber member adjacent to the coating layer become close to each other, so that the stress dispersion effect during traveling can be obtained, and the durability of the transponder can be effectively improved.

The transponder is coated with a coating layer, and the storage elastic modulus E'c (60 ° C.) of the coating layer at 60 ° C. and the storage elastic modulus E'a (60 ° C.) of the rubber member adjacent to the outer side of the coating layer in the tire width direction at 60 ° C. ° C.) preferably satisfies the relationship of 0.2 ≦ E'c (60 ° C.) / E'a (60 ° C.) ≦ 1.2. As a result, the physical properties of the coating layer and the rubber member adjacent to the coating layer become close to each other, so that the stress dispersion effect during traveling can be obtained, and the durability of the transponder can be effectively improved.

The transponder is coated with a coating layer, and the storage elastic modulus E'c (20 ° C.) of the coating layer at 20 ° C. is preferably in the range of 2 MPa to 12 MPa. Thereby, the durability of the transponder can be effectively improved.

The transponder is coated with a coating layer, and the storage elastic modulus E'c (20 ° C.) of the coating layer at 20 ° C. and the storage elastic modulus E'c (60 ° C.) of 60 ° C. of the coating layer are 1.0 ≦ E'c. It is preferable to satisfy the relationship of (20 ° C.) / E'c (60 ° C.) ≤ 1.5. As a result, the temperature dependence of the coating layer is reduced, so that the coating layer does not soften even if the temperature of the tire rises during high-speed running, and the durability of the transponder can be effectively improved.

The transponder is coated with a coating layer, and the relative permittivity of the coating layer is preferably 7 or less. As a result, the transponder is protected by the coating layer, the durability of the transponder can be improved, the radio wave transmission of the transponder can be ensured, and the communication property of the transponder can be effectively improved.

The transponder is preferably coated with a coating layer, which is preferably composed of a rubber or elastomer and a white filler of 20 phr or more. As a result, the relative permittivity of the coating layer can be made relatively low as compared with the case where carbon is contained, and the communication property of the transponder can be effectively improved.

The white filler preferably contains 20 phr to 55 phr of calcium carbonate. As a result, the relative permittivity of the coating layer can be made relatively low, and the communication property of the transponder can be effectively improved.

It is preferable that the center of the transponder is arranged at a distance of 10 mm or more in the tire circumferential direction from the splice portion of the tire component member. Thereby, the durability of the tire can be effectively improved.

It is preferable that the transponder is arranged between the position 15 mm outward in the tire radial direction from the upper end of the bead core of the bead portion and the tire maximum width position. As a result, since the transponder is arranged in a region where the stress amplitude during traveling is small, the durability of the transponder can be effectively improved, and the durability of the tire is not lowered.

The distance between the cross-sectional center of the transponder and the outer surface of the tire is preferably 2 mm or more. As a result, the durability of the tire can be effectively improved, and the traumatic resistance of the tire can be improved.

The transponder is coated with a coating layer, and the thickness of the coating layer is preferably 0.5 mm to 3.0 mm. As a result, the communication property of the transponder can be effectively improved without causing unevenness on the outer surface of the tire.

The transponder has an IC board for storing data and an antenna for transmitting and receiving data, and the antenna is preferably spiral. As a result, it is possible to follow the deformation of the tire during running, and it is possible to improve the durability of the transponder.

In the present invention, the storage elastic modulus E'is based on JIS-K6394, using a viscoelastic spectrometer, and in the tensile deformation mode, each specified temperature, frequency 10 Hz, initial strain 10%, dynamic strain ± 2 It is measured under the condition of%.

It is a meridian semi-cross-sectional view which shows the pneumatic tire which comprises the embodiment of this invention. FIG. 5 is a cross-sectional view taken along the meridian line schematically showing the pneumatic tire of FIG. FIG. 5 is a cross-sectional view taken along the equator line schematically showing the pneumatic tire of FIG. FIG. 5 is an enlarged cross-sectional view showing a transponder embedded in the pneumatic tire of FIG. 1. (A) and (b) are perspective views which show the transponder which can be embedded in the pneumatic tire which concerns on this invention. It is explanatory drawing which shows the tire radial position of a transponder in a test tire.

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.

As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and these. It includes a pair of bead portions 3 arranged inside the sidewall portion 2 in the tire radial direction.

At least one layer (one layer in FIG. 1) of the carcass layer 4 formed by arranging a plurality of carcass cords in the radial direction is mounted between the pair of bead portions 3. The carcass layer 4 is covered with rubber. As the carcass cord constituting the carcass layer 4, an organic fiber cord such as nylon or polyester is 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 arranged on the outer periphery of the bead core 5.

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

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

In the pneumatic tire, both terminals 4e of the carcass layer 4 are arranged so as to be folded back from the inside to the outside of each bead core 5 and to wrap the bead core 5 and the bead filler 6. The carcass layer 4 is wound around the bead core 5 in each bead portion 3 and the 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 is wound up on each sidewall portion 2 side. It includes a winding portion 4B which is a portion extending toward the direction.

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

Further, in the pneumatic tire, the transponder 20 is embedded in a portion outside the carcass layer 4 in the tire width direction. The transponder 20 extends along the tire circumferential direction. The transponder 20 may be arranged so as to be inclined in the range of −10 ° to 10 ° with respect to the tire circumferential direction.

As the transponder 20, for example, an RFID (Radio Frequency Identification) tag can be used. As shown in FIGS. 5A and 5B, the transponder 20 has an IC substrate 21 for storing data and an antenna 22 for transmitting and receiving data in a non-contact manner. By using such a transponder 20, it is possible to write or read information about the tire in a timely manner and manage the tire efficiently. RFID is an automatic recognition technology that is composed of a reader / writer having an antenna and a controller, an IC board, and an ID tag having an antenna, and can communicate data wirelessly.

The overall shape of the transponder 20 is not particularly limited, and for example, a columnar or plate-shaped transponder can be used as shown in FIGS. 5A and 5B. In particular, when the columnar transponder 20 shown in FIG. 5A is used, it is preferable because it can follow the deformation of the tire in each direction. In this case, the transponder 20's antenna 22 protrudes from each of both ends of the IC substrate 21 and has a spiral shape. As a result, it is possible to follow the deformation of the tire during traveling, and it is possible to improve the durability of the transponder 20. Further, the communicability can be ensured by appropriately changing the length of the antenna 22.

Further, in the pneumatic tire, among the rubber members (the sidewall rubber layer 12 and the rim cushion rubber layer 13 in FIG. 1) located outside the transponder 20 in the tire width direction, the rubber member having the largest storage elastic modulus at 20 ° C. (Hereinafter, it may be referred to as an outer member) corresponds to the rim cushion rubber layer 13. On the other hand, among the rubber members located inside the transponder 20 in the tire width direction (the coated rubber of the carcass layer 4, the bead filler 6 and the inner liner layer 9 in FIG. 1), the rubber member having the highest storage elastic modulus at 20 ° C. (hereinafter referred to as (Sometimes referred to as an inner member) corresponds to the bead filler 6. The rubber member (outer member or inner member) having the highest storage elastic modulus at 20 ° C. does not include the coating layer 23 that covers the transponder 20 described later.

Here, the storage elastic modulus E'out (50 ° C.) at 50 ° C. and the storage elastic modulus E'out (150 ° C.) at 150 ° C. in the outer member are 1.0 ≦ E'out (50 ° C.) / E'out ( Satisfying the relationship of 150 ° C.) ≤ 2.0, the storage elastic modulus E'in (50 ° C.) at 50 ° C. and the storage elastic modulus E'in (150 ° C.) at 150 ° C. in the inner member are 1.0 ≤ E'in. The relationship of (50 ° C.) / E'in (150 ° C.) ≤ 4.0 is satisfied. In particular, 1.0 ≤ E'out (50 ° C) / E'out (150 ° C) ≤ 1.6 and 1.1 ≤ E'in (50 ° C) / E'in (150 ° C) ≤ 2.5. It is preferable to satisfy the relationship.

At that time, the storage elastic modulus E'out (20 ° C.) of 20 ° C. in the outer member can be set in the range of 8 MPa to 12 MPa in the region inside the tire radial direction from the apex of the bead filler 6, and the inner member can be set. The storage elastic modulus E'in (20 ° C.) at 20 ° C. in the above can be set in the range of 8 MPa to 110 MPa. Further, the storage elastic modulus E'out (50 ° C.) at 50 ° C. of the outer member is set in the range of 7 MPa to 10 MPa, and the storage elastic modulus E'in (50 ° C.) of 50 ° C. of the inner member is set to 7 MPa to 80 MPa. can do. Further, in the flex zone outside the tire radial direction from the apex of the bead filler 6, the storage elastic modulus E'out (20 ° C.) of 20 ° C. in the outer member can be set in the range of 3 MPa to 5 MPa, and is inside. The storage elastic modulus E'in (20 ° C.) at 20 ° C. of the material can be set to 5 MPa to 7 MPa. Further, the storage elastic modulus E'out (50 ° C.) of 50 ° C. in the outer member can be set in the range of 2 MPa to 4 MPa, and the storage elastic modulus E'in (50 ° C.) of 50 ° C. in the inner member can be set. It can be set to 2 MPa to 6 MPa.

In the embodiment of FIG. 1, the transponder 20 is arranged between the winding portion 4B of the carcass layer 4 and the rim cushion 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 and the inner member change depending on the location of the transponder 20, but in any case, the storage elastic modulus E'out (50 ° C) at 50 ° C. and the storage elastic modulus E'out at 150 ° C. in the outer member. The out (150 ° C.) and the storage elastic modulus E'in (50 ° C.) of 50 ° C. and the storage elastic modulus E'in (150 ° C.) of 150 ° C. in the inner member are set so as to satisfy the above-mentioned relational expressions. NS.

In the above-mentioned pneumatic tire, since the transponder 20 is embedded outside the carcass layer 4 in the tire width direction, there is no tire component that blocks radio waves during communication of the transponder 20, and the communication property of the transponder 20 can be ensured. can. Further, among the rubber members located outside the transponder 20 in the tire width direction, the rubber member having the largest storage elastic modulus at 20 ° C. has a storage elastic modulus E'out (50 ° C.) of 50 ° C. and a storage elastic modulus E'out (50 ° C.) of 150 ° C. out (150 ° C.) satisfies the relationship of 1.0 ≤ E'out (50 ° C.) / E'out (150 ° C.) ≤ 2.0, and 20 ° C. of the rubber members located inside the transponder 20 in the tire width direction. The storage elastic modulus E'in (50 ° C.) at 50 ° C. and the storage elastic modulus E'in (150 ° C.) at 150 ° C. in the rubber member having the largest storage elastic modulus are 1.0 ≦ E'in (50 ° C.) / Since the relationship of E'in (150 ° C.) ≤ 4.0 is satisfied, the rigidity of the rubber members located inside and outside the transponder 20 is maintained even when the temperature of the tire becomes high, and sufficient strength can be secured. At the same time, stress concentration at the time of tire deformation can be suppressed. As a result, the durability of the tire can be improved while ensuring the durability of the transponder 20.

In general, a member having a high temperature dependence (prone to heat generation) tends to have a lower storage elastic modulus in a high temperature range (for example, 150 ° C.) than a storage elastic modulus in a medium temperature range (for example, 50 ° C.) at a high temperature. The ratio of the storage elastic modulus in the medium temperature range to the storage elastic modulus in the high temperature range exceeds 1.0. On the other hand, when the value of E'out (50 ° C.) / E'out (150 ° C.) or E'in (50 ° C.) / E'in (150 ° C.) is smaller than the lower limit, the inside of the transponder 20 or Stress concentration occurs when the tire is deformed in the rubber member located on the outside, and the durability of the transponder 20 deteriorates. Conversely, if the value of E'out (50 ° C) / E'out (150 ° C) or E'in (50 ° C) / E'in (150 ° C) is greater than the upper limit, as the tire gets hotter, The rigidity of the rubber member located inside or outside the transponder 20 tends to decrease as compared with the case where the temperature is 50 ° C., and the strength of the rubber member decreases, leading to a decrease in tire durability.

In the relationship between the temperature dependence of the physical properties of the outer member and the temperature dependence of the physical properties of the inner member, in order to enhance the protection of the transponder 20 against tire deformation during running, 0.2 × E'in (50 ° C.) / It is preferable to satisfy the relationship of E'in (150 ° C.) ≤ E'out (50 ° C.) / E'out (150 ° C.) ≤ 1.8 x E'in (50 ° C.) / E'in (150 ° C.). .. In particular, when the JIS hardness (20 ° C.) of the inner member is relatively high, the value of E'in (50 ° C.) / E'in (150 ° C.) is E'out (50 ° C.) / E'out (150 ° C.). Since the value of (° C.) is larger (the inner member is more temperature-dependent than the outer member) and the inner member is more likely to soften at high temperatures, the protection of the transponder 20 can be enhanced by the buffering effect. When the JIS hardness (20 ° C.) of the inner member is relatively low, the values of E'in (50 ° C.) / E'in (150 ° C.) and E'out (50 ° C.) / E'out (150 ° C.) Since the values of (° C.) are almost the same, stress concentration is suppressed around the transponder 20, which is also effective in improving the durability of the tire.

In the above-mentioned pneumatic tire, the transponder 20 has a position P1 15 mm outward in the tire radial direction from the upper end 5e (outer end in the tire radial direction) of the bead core 5 and a position where the maximum width of the tire is obtained, as an arrangement area in the tire radial direction. It is preferable that it is arranged between P2 and P2. That is, it is preferable that the transponder 20 is arranged in the region S1 shown in FIG. When the transponder 20 is arranged in the region S1, since the transponder 20 is located in the region where the stress amplitude during running is small, the durability of the transponder 20 can be effectively improved, and the durability of the tire is further lowered. I won't let you. Here, if the transponder 20 is arranged inside the position P1 in the tire radial direction, the transponder 20 tends to have poor communication performance because it is close to a metal member such as the bead core 5. On the other hand, when the transponder 20 is arranged outside the position P2 in the tire radial direction, the transponder 20 is located in a region where the stress amplitude during running is large, and the transponder 20 itself is damaged or the interface is peeled off around the transponder 20. Is not preferable because it tends to occur.

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

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

As shown in FIG. 4, the distance d between the cross-sectional center of the transponder 20 and the outer surface of the tire is preferably 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, and the traumatic resistance of the tire can be improved.

Further, the transponder 20 is preferably covered with a coating layer 23. The coating layer 23 covers the entire transponder 20 so as to sandwich both the front and back surfaces of the transponder 20. The coating layer 23 may be made of rubber having the same physical characteristics as the rubber constituting the sidewall rubber layer 12 or the rim cushion rubber layer 13, or may be made of rubber having different physical characteristics. Since the transponder 20 is protected by the coating layer 23, the durability of the transponder 20 can be improved.

Hereinafter, the coating layer 23 that covers the transponder 20 will be described in detail. Regarding the physical properties of the coating layer 23, the storage elastic modulus E'c (20 ° C.) of the coating layer 23 at 20 ° C. is preferably in the range of 2 MPa to 12 MPa. By setting the physical properties of the coating layer 23 in this way, the durability of the transponder 20 can be effectively improved.

The storage elastic modulus E'c (20 ° C.) of the coating layer 23 at 20 ° C. and the storage elastic modulus E'c (60 ° C.) of 60 ° C. of the coating layer 23 are 1.0 ≦ E'c (20 ° C.). It is preferable to satisfy the relationship of / E'c (60 ° C.) ≤ 1.5. By setting the physical properties of the coating layer 23 in this way, the temperature dependence of the coating layer 23 becomes low (the coating layer 23 is less likely to generate heat), so that even if the temperature of the tire rises during high-speed running, the coating layer 23 Does not soften, and the durability of the transponder 20 can be effectively improved.

Further, the storage elastic modulus E'c (20 ° C.) of the coating layer 23 at 20 ° C. and the storage elasticity of the coating layer 23 adjacent to the outside in the tire width direction (rim cushion rubber layer 13 in FIG. 4) at 20 ° C. The rate E'a (20 ° C.) preferably satisfies the relationship of 0.1 ≦ E'c (20 ° C.) / E'a (20 ° C.) ≦ 1.5, and 0.15 ≦ E'c ( It is more preferable to satisfy the relationship of 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 close to each other, so that the stress dispersion effect during traveling can be obtained, and the durability of the transponder 20 can be improved. It can be effectively improved.

The storage elastic modulus E'c (60 ° C.) of the coating layer 23 at 60 ° C. and the storage elastic modulus E'a (60 ° C.) of the rubber member adjacent to the outer side of the coating layer 23 in the tire width direction at 60 ° C. are 0. It is preferable to satisfy the relationship of .2 ≦ E'c (60 ° C.) / E'a (60 ° C.) ≦ 1.2. By setting the physical properties of the coating layer 23 and the rubber member adjacent to the coating layer 23 in this way, the physical properties of both become close to each other, so that the stress dispersion effect during traveling can be obtained, and the durability of the transponder 20 can be improved. It can be effectively improved.

As the composition of the coating layer 23, it is preferable that the coating layer 23 is composed of a rubber or an elastomer and a white filler of 20 phr or more. By configuring the coating layer 23 in this way, the relative permittivity of the coating layer 23 can be made relatively low as compared with the case where carbon is contained, and the communication property of the transponder 20 can be effectively improved. .. In addition, in this specification, "phr" means a part by weight per 100 parts by weight of a rubber component (elastomer).

The white filler constituting the coating layer 23 preferably contains 20 phr to 55 phr of calcium carbonate. As a result, the relative permittivity of the coating layer 23 can be made relatively low, and the communicability of the transponder 20 can be effectively improved. However, if the white filler contains excessive calcium carbonate, it becomes brittle and the strength of the coating layer 23 decreases, which is not preferable. Further, the coating layer 23 can optionally contain silica (white filler) of 20 phr or less and carbon black of 5 phr or less in addition to calcium carbonate. When a small amount of silica or carbon black is used in combination, the relative dielectric constant of the coating layer 23 can be lowered while ensuring the strength.

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, it is possible to secure radio wave transmission when the transponder 20 radiates radio waves and effectively improve the communication property of the transponder 20. The relative permittivity of the rubber constituting the coating layer 23 is a relative permittivity of 860 MHz to 960 MHz at room temperature. Here, the normal temperature conforms to the standard state of the JIS standard, and 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 assigned frequency of RFID in the UHF band, but when the above-mentioned allotted frequency is changed, the relative permittivity of the allotted frequency range may be defined as described above.

The thickness t of the coating layer 23 is preferably 0.5 mm to 3.0 mm, more preferably 1.0 mm to 2.5 mm. Here, the thickness t of the coating layer 23 is the rubber thickness at the position including the transponder 20, and is, for example, on a straight line passing through the center of the transponder 20 and orthogonal to the outer surface of the tire as shown in FIG. It is the total rubber thickness of the thickness t1 and the thickness t2. By appropriately setting the thickness t of the coating layer 23 in this way, the communication performance of the transponder 20 can be effectively improved without causing unevenness on the 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 property of the transponder 20 cannot be obtained, and conversely, if the thickness t of the coating layer 23 exceeds 3.0 mm, The outer surface of the tire is uneven, which is not preferable in appearance. The cross-sectional shape of the covering layer 23 is not particularly limited, but for example, a triangular shape, a rectangular shape, a trapezoidal shape, or a spindle shape can be adopted. The coating layer 23 of FIG. 4 has a substantially spindle-shaped cross-sectional shape.

In the above-described embodiment, the terminal 4e of the winding portion 4B of the carcass layer 4 is arranged near the upper end 6e of the bead filler 6, but the present invention is not limited to this, and the winding portion 4B of the carcass layer 4 is not limited to this. The terminal 4e can be arranged at any height. For example, the terminal 4e of the winding portion 4B of the carcass layer 4 may be arranged on the side of the bead core 5. In such a low tanup structure, the transponder 20 can be arranged between the bead filler 6 and the sidewall rubber layer 12 or the rim cushion rubber layer 13. At that time, the rubber member adjacent to the outer side of the coating layer 23 in the tire width direction is the sidewall rubber layer 12 or the rim cushion rubber layer 13.

With a tire size of 265 / 40ZR20, a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and these sidewall portions are arranged inside the tire radial direction. In a pneumatic tire having a pair of bead portions and 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, and E'out. (50 ° C) / E'out (150 ° C), E'in (50 ° C) / E'in (150 ° C), presence / absence of coating layer, relative permittivity of coating layer, thickness of coating layer, Tread E'c (20 ° C), Tread E'c (60 ° C), E'c (20 ° C) / E'a (20 ° C), E'c (60 ° C) / E Tires of Comparative Examples 1 to 4 and Examples 1 to 14 in which'a (60 ° C.) and E'c (20 ° C.) / E'c (60 ° C.) were set as shown in Tables 1 and 2 were produced.

In Comparative Examples 1 to 4 and Examples 1 to 14, a columnar transponder was used, the distance in the tire circumferential direction from the center of the transponder to the splice portion of the tire component was set to 10 mm, and the distance from the center of the cross section of the transponder to the outside of the tire was set. The distance to the surface was set to 2 mm or more.

In Tables 1 and 2, when the position of the transponder in the tire width direction is "inside", it means that the transponder is arranged inside the carcass layer in the tire width direction, and the position of the transponder in the tire width direction is "outside". In the case of ", it means that the transponder is arranged outside the carcass layer in the tire width direction. Further, in Tables 1 and 2, the positions of the transponders in the tire radial direction correspond to the respective positions A to E shown in FIG.

In Comparative Examples 2 to 4 and Examples 1 to 14, the outer member is a rim cushion rubber layer, and the inner member is a bead filler. That is, in Tables 1 and 2, "E'out (50 ° C.) / E'out (150 ° C.)" is the ratio of the storage elastic modulus in the rim cushion rubber layer which is the outer member, and is "E'in ( "50 ° C.) / E'in (150 ° C.)" is the ratio of the storage elastic modulus of the bead filler, which is an inner member. Further, "E'c (20 ° C.) / E'a (20 ° C.)" and "E'c (60 ° C.) / E'a (60 ° C.)" are rubbers adjacent to the outer side of the coating layer in the tire width direction. It is the ratio of the storage elastic modulus of the coating layer to the storage elastic modulus of the rim cushion rubber layer which is a member. "E'c (20 ° C.) / E'c (60 ° C.)" is the ratio of the storage elastic modulus in the coating layer. For Comparative Example 1, for convenience, the physical characteristics of the rim cushion rubber layer were displayed as the physical characteristics of the outer member, and the physical characteristics of the bead filler were displayed as the physical characteristics of the inner member.

For these test tires, tire evaluation (durability) and transponder evaluation (communication and durability) were carried out by the following test methods, and the results are shown in Tables 1 and 2.

Durability (tires and transponders):
Each test tire was assembled to a standard rim wheel, and a running test was conducted with a drum tester under the conditions of an air pressure of 120 kPa, 102% of the maximum load, and a running speed of 81 km. Was measured. The evaluation results are shown by an index with Comparative Example 2 as 100. The larger the index value, the better the durability of the tire. Furthermore, for each test tire after running, it was confirmed whether the transponder could communicate and whether it was damaged, and the case where communication was possible and there was no damage was indicated by "◎ (excellent)", and communication was possible but there was damage. Cases are indicated by "○ (good)", and cases where communication is not possible are indicated by three stages of "× (impossible)".

Communication (transponder):
For each test tire, communication work with the transponder was carried out using a reader / writer. Specifically, the maximum distance that can be communicated with a reader / writer with an output of 250 mW and a carrier frequency of 860 MHz to 960 MHz was measured. The evaluation results are shown by an index with Comparative Example 2 as 100. The larger the index value, the better the communication.

As can be seen from Tables 1 and 2, the pneumatic tires of Examples 1 to 14 have improved tire durability and transponder communication and durability in a well-balanced manner as compared with Comparative Example 2.

On the other hand, in Comparative Example 1, since the transponder was arranged inside the carcass layer in the tire width direction, the communication property of the transponder deteriorated. In Comparative Examples 1 and 3, the value of E'out (50 ° C.) / E'out (150 ° C.) or E'in (50 ° C.) / E'in (150 ° C.) is larger than the range specified in the present invention. Since it was set low, the effect of improving the durability of the transponder could not be obtained. In Comparative Example 4, the values of E'out (50 ° C.) / E'out (150 ° C.) and E'in (50 ° C.) / E'in (150 ° C.) are set higher than the range specified in the present invention. Therefore, the durability of the tire deteriorated.

1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 12 Side wall rubber layer 13 Rim cushion rubber layer 20 Transponder CL Tire center line

Claims (13)

A tread portion extending in the tire circumferential direction 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 inside the tire radial direction of these sidewall portions. In a pneumatic tire in which 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 among the rubber members located outside the transponder in the tire width direction, the rubber member having the largest storage elastic modulus at 20 ° C. has a storage elastic modulus E'out at 50 ° C. The storage elastic modulus E'out (150 ° C.) at 50 ° C.) and 150 ° C. satisfies the relationship of 1.0 ≦ E'out (50 ° C.) / E'out (150 ° C.) ≦ 2.0. Among the rubber members located inside in the width direction, the rubber member having the highest storage elastic modulus at 20 ° C. has a storage elastic modulus E'in (50 ° C.) of 50 ° C. and a storage elastic modulus E'in (150 ° C.) of 150 ° C. A pneumatic tire characterized by satisfying the relationship of 1.0 ≤ E'in (50 ° C.) / E'in (150 ° C.) ≤ 4.0. The transponder is coated with a coating layer, and the storage elastic modulus E'c (20 ° C.) of the coating layer at 20 ° C. and the storage elastic modulus E'c (20 ° C.) of the rubber member adjacent to the outer side of the coating layer in the tire width direction at 20 ° C. The pneumatic tire according to claim 1, wherein a (20 ° C.) satisfies the relationship of 0.1 ≦ E'c (20 ° C.) / E'a (20 ° C.) ≦ 1.5. The transponder is coated with a coating layer, and the storage elastic modulus E'c (60 ° C.) of the coating layer at 60 ° C. and the storage elastic modulus E'c (60 ° C.) of the rubber member adjacent to the outer side of the coating layer in the tire width direction at 60 ° C. The pneumatic tire according to claim 1 or 2, wherein a (60 ° C.) satisfies the relationship of 0.2 ≦ E'c (60 ° C.) / E'a (60 ° C.) ≦ 1.2. .. The invention according to any one of claims 1 to 3, wherein the transponder is coated with a coating layer, and the storage elastic modulus E'c (20 ° C.) of the coating layer at 20 ° C. is in the range of 2 MPa to 12 MPa. Pneumatic tires. The transponder is coated with a coating layer, and the storage elastic modulus E'c (20 ° C.) of the coating layer at 20 ° C. and the storage elastic modulus E'c (60 ° C.) of 60 ° C. of the coating layer are 1.0 ≦. The pneumatic tire according to any one of claims 1 to 4, wherein the relationship of E'c (20 ° C.) / E'c (60 ° C.) ≤ 1.5 is satisfied. The pneumatic tire according to any one of claims 1 to 5, wherein the transponder is coated with a coating layer, and the relative permittivity of the coating layer is 7 or less. The pneumatic tire according to any one of claims 1 to 6, wherein the transponder is coated with a coating layer, and the coating layer is composed of a rubber or an elastomer and a white filler of 20 phr or more. The pneumatic tire according to claim 7, wherein the white filler contains 20 phr to 55 phr of calcium carbonate. The pneumatic tire according to any one of claims 1 to 8, wherein the center of the transponder is arranged at a distance of 10 mm or more in the tire circumferential direction from the splice portion of the tire component member. The inflated according to any one of claims 1 to 9, wherein the transponder is arranged between a position 15 mm outward in the tire radial direction from the upper end of the bead core of the bead portion and a tire maximum width position. tire. The pneumatic tire according to any one of claims 1 to 10, wherein the distance between the cross-sectional center of the transponder and the outer surface of the tire is 2 mm or more. The pneumatic tire according to any one of claims 1 to 11, wherein the transponder is coated with a coating layer, and the thickness of the coating layer is 0.5 mm to 3.0 mm. The pneumatic tire according to any one of claims 1 to 12, wherein the transponder has an IC substrate for storing data and an antenna for transmitting and receiving data, and the antenna has a spiral shape.

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