Pneumatic tire

Abstract

To provide a pneumatic tire configured so that communication performance of a transponder can be improved and crack resistance of the tire can be improved.SOLUTION: The pneumatic tire comprises a tread part 1 formed in an annular shape extending in a tire circumferential direction, a pair of side wall parts 2 arranged at both sides of the tread part 1, and a pair of bead parts 3 arranged inside in a tire radial direction of the side wall parts 2. Bead fillers 6 are arranged on outer peripheries of bead cores 5 of the bead parts 3, and a carcass layer 4 is stretched between the pair of bead parts 3. The carcass layer 4 is wound up around the bead cores 5, from the inside of the tire toward the outside thereof. A transponder 20 is buried between the bead filler 6 and the carcass layer 4. A distance W measured in a normal direction of the carcass layer 4 from an outer side surface of the transponder 20 to an outer side surface of the bead filler 6 is in a range of 2 mm-20 mm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pneumatic tire having an embedded transponder, and more particularly to a pneumatic tire that enables improvement in crack resistance of the tire while improving the communication performance of the transponder. [Background technology]

[0002] It has been proposed to embed an RFID tag (transponder) inside a pneumatic tire (see, for example, Patent Document 1). When a transponder is embedded inside a green tire and then vulcanized, depending on the location where the transponder is embedded, poor rubber flow may occur during vulcanization, which may result in the problem of cracks easily occurring on the tire surface after vulcanization. The occurrence of such cracks is more pronounced when the transponder is embedded in a location where the tire's rubber gauge is excessively thin. Conversely, when the transponder is embedded in a location where the tire's rubber gauge is excessively thick, there is a problem of the transponder's communication capabilities being degraded. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-137510 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a pneumatic tire that can improve the crack resistance of the tire while improving the communication performance of the transponder. [Means for solving the problem]

[0005] In order to achieve the above object, the pneumatic tire of the present invention comprises a tread portion extending circumferentially in a ring shape and a pair of sidewall portions arranged on either side of the tread portion, and a pair of bead portions arranged radially inward of the sidewall portions, wherein a bead filler is arranged on the outer periphery of the bead core of each bead portion, a carcass layer is mounted between the pair of bead portions, and the carcass layer is wound up around the bead core from the inside to the outside of the tire, wherein a transponder is embedded between the bead filler and the carcass layer, and the distance W measured in the normal direction of the carcass layer from the outer surface of the transponder to the outer surface of the bead filler is in the range of 2 mm to 20 mm. [Effects of the Invention]

[0006] In the present invention, a transponder is embedded between the bead filler and the carcass layer. A typical transponder is approximately 1 mm to 2 mm thick. However, if the transponder is embedded between the bead filler and the carcass layer in a position where the above-mentioned rubber gauge cannot be ensured, the thickness of the transponder will cause poor rubber flow during tire vulcanization. In contrast, in the present invention, the distance W from the outer surface of the transponder to the outer surface of the bead filler is set to a range of 2 mm to 20 mm. This allows the transponder to be positioned so that the rubber gauge is not excessively thick while still ensuring a rubber gauge that does not cause poor rubber flow during vulcanization. This improves the transponder's communication capabilities and the tire's crack resistance.

[0007] In the pneumatic tire of the present invention, the maximum thickness t of the transponder and the distance W preferably satisfy the relationship 1≦W / t≦10. This makes it possible to suppress poor rubber flow during tire vulcanization, thereby effectively improving crack resistance.

[0008] The bead filler preferably comprises a first bead filler disposed adjacent to the bead core on the radially outer side of the tire, and a second bead filler disposed adjacent to the first bead filler on the radially outer side of the tire, and the transponder is preferably disposed between the second bead filler and the carcass layer, which brings the transponder closer to the outer surface of the sidewall portion than when the transponder is disposed in the first bead filler, thereby effectively improving the transponder's communication performance.

[0009] The hardness of the second bead filler is lower than that of the first bead filler, and is preferably in the range of 55 to 65. Because the second bead filler in which the transponder is embedded is made of a relatively soft rubber, the second bead filler absorbs impacts and makes it difficult for the impacts to be transmitted to the transponder, thereby preventing damage to the transponder.

[0010] The carcass cords constituting the carcass layer are preferably metal cords, which increases the bending rigidity of the carcass cords and makes the carcass cords less likely to bend when the green tire comes into contact with the mold during vulcanization, thereby effectively improving crack resistance.

[0011] It is preferable that a metal reinforcing layer be disposed on the outer side of the carcass layer in the bead portion, since the provision of such a metal reinforcing layer increases bending rigidity, making it difficult for the green tire to bend when it comes into contact with the mold during vulcanization, thereby effectively improving crack resistance.

[0012] The metal reinforcing layer is preferably wound up around the bead core from the inside to the outside of the tire, and the transponder is preferably disposed radially outward of the wound-up end of the metal reinforcing layer. This allows the transponder to be disposed away from the metal member, thereby effectively improving the transponder's communication performance. Furthermore, since the transponder is disposed so that the step at the wound-up end of the carcass layer and the step at the transponder do not overlap, the amount of the step is reduced, and the occurrence of cracks on the tire surface due to poor rubber flow can be suppressed.

[0013] The transponder is preferably disposed radially outward of the wound-up end of the carcass layer. For example, when used in a heavy-duty tire, the carcass cord is made of a metal cord, so the transponder is disposed away from the metal member, improving the transponder's communication performance. Furthermore, since the transponder is disposed so that the step at the wound-up end of the carcass layer and the step at the transponder do not overlap, the amount of the step is reduced, and the occurrence of cracks on the tire surface due to poor rubber flow can be suppressed.

[0014] The entire transponder is covered with a rubber coating layer, and the absolute value of the difference between the width w1 of the coating layer on the side in contact with the carcass layer and the width w2 of the coating layer on the side in contact with the bead filler, |w1-w2|, is preferably 0.2 mm or more. This reduces the amount of step around the transponder, effectively improving crack resistance. Furthermore, the shape of the coating layer can be stabilized, effectively improving the communication performance of the transponder. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a meridian cross-sectional view showing an example of a pneumatic tire according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a main part of the pneumatic tire of FIG. [Figure 3] FIG. 10 is a cross-sectional view showing a main portion of a modified example of a pneumatic tire according to an embodiment of the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing a main portion of another modified example of a pneumatic tire according to an embodiment of the present invention. [Figure 5] FIG. 10 is a cross-sectional view showing a main portion of another modified example of a pneumatic tire according to an embodiment of the present invention. [Figure 6] 6(a) and 6(b) are enlarged views of the transponder embedded in the pneumatic tire of FIG. 5, where 6(a) is a perspective view and 6(b) is a cross-sectional view. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: Figures 1 and 2 show a pneumatic tire according to an embodiment of the present invention;

[0017] As shown in FIG. 1, the pneumatic tire of this embodiment includes a tread portion 1 extending circumferentially of the tire to form an annular shape, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged radially inward of the sidewall portions 2.

[0018] At least one carcass layer 4 (one layer in Figure 1) is mounted between a pair of bead portions 3, and is made up of multiple carcass cords arranged in the radial direction. The carcass cords that make up the carcass layer 4 are preferably made of metal cords such as steel cords. This increases the bending rigidity of the carcass cords, making them less likely to bend when the green tire comes into contact with the mold during vulcanization, thereby contributing to improved crack resistance. An annular bead core 5 is embedded in each bead portion 3, and a bead filler 6 made of a rubber composition with a triangular cross section is arranged on the outer periphery of the bead core 5.

[0019] A plurality of belt layers 7 (four layers in FIG. 1 ) are embedded on the tire radially outer side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of belt cords (e.g., steel cords) inclined with respect to the tire circumferential direction. These belt layers 7 include two central main belt layers 72, 73 in which the belt cords intersect with each other, and auxiliary belt layers 71, 74 disposed on the tire radially inner and outer sides of these main belt layers 72, 73. The inclination angle of the belt cords constituting the main belt layers 72, 73 with respect to the tire circumferential direction is set within a range of 15° to 35°, for example, and the inclination angle of the belt cords constituting the auxiliary belt layers 71, 74 with respect to the tire circumferential direction is set within a range of 15° to 75°, for example.

[0020] In the pneumatic tire described above, the turned-up end 4e of the carcass layer 4 is positioned radially inward relative to the radially outer end 6e of the bead filler 6. That is, the turned-up end 4e of the carcass layer 4 terminates at the midsection of the bead filler 6. A reinforcing layer 10 is disposed in each bead portion 3 so as to encase the carcass layer 4, bead core 5, and bead filler 6. The reinforcing layer 10 includes at least one metal reinforcing layer 11 (one layer in FIG. 1 ) containing multiple metal cords (e.g., steel cords) and at least one non-metal reinforcing layer 12 (two layers in FIG. 1 ) containing multiple organic fiber cords and disposed outward of the metal reinforcing layer 11 in the tire width direction. The presence of such a metal reinforcing layer increases bending rigidity, reducing bending resistance when the green tire contacts a mold during vulcanization, thereby contributing to improved crack resistance. Furthermore, a sidewall rubber layer 13 exposed on the outer surface of the tire is disposed in the region extending from the sidewall portion 2 to the bead portion 3.

[0021] A rim cushion rubber layer 14 is disposed between the bead filler 6 and the sidewall rubber layer 13. The rim cushion rubber layer 14 extends from a lateral position of the bead filler 6 toward the inside in the tire radial direction. In other words, the rim cushion rubber layer 14 is disposed in a region ranging from a position radially inward of the outer end 6e of the bead filler 6 in the tire radial direction to a position radially inward of the bead core 5. The rim cushion rubber layer 14 is disposed so as to cover the turned-up end 4e of the carcass layer 4, the turned-up end of the metal reinforcing layer 11, and the non-metal reinforcing layer 12.

[0022] In the pneumatic tire, a transponder 20 is embedded between the bead filler 6 and the carcass layer 4. In Fig. 2, the transponder 20 is embedded in the interface between the carcass layer 4 and the inner side surface (inner surface) of the bead filler 6 in the tire width direction. The transponder 20 is arranged to extend along the tire circumferential direction.

[0023] The distance W (see FIG. 2) from the outer side surface (outer surface) of the transponder 20 in the tire width direction to the outer side surface (outer surface) of the bead filler 6 in the tire width direction is set to a range of 2 mm to 20 mm. This distance W is preferably in the range of 5 mm to 10 mm. Note that the distance W is measured in the normal direction of the carcass layer 4 with which the transponder 20 abuts.

[0024] For example, an RFID (Radio Frequency Identification) tag can be used as the transponder 20. The transponder 20 has an IC board for storing data and an antenna for contactlessly transmitting and receiving data. By using such a transponder 20, tire-related information can be written or read as needed, enabling efficient tire management. RFID is an automatic identification technology that is composed of a reader / writer with an antenna and a controller, and an ID tag with an IC board and an antenna, and is capable of wirelessly exchanging data.

[0025] The entire transponder 20 is preferably covered with a covering layer made of rubber. This covering layer is formed, for example, by sandwiching the front and back surfaces of the transponder 20 between two rubber sheets to cover the entire transponder 20. Protecting the transponder 20 with the covering layer in this manner improves the adhesiveness and durability of the transponder 20.

[0026] In the pneumatic tire described above, the transponder 20 is embedded between the bead filler 6 and the carcass layer 4, and the distance W from the outer surface of the transponder 20 to the outer surface of the bead filler 6 is set in the range of 2 mm to 20 mm, so that the transponder 20 can be positioned so that the rubber gauge does not become excessively thick while ensuring that poor rubber flow does not occur during vulcanization. This improves the communication performance of the transponder 20 and the crack resistance of the tire.

[0027] In the pneumatic tire, the maximum thickness t of the transponder 20 (see FIG. 2) and the distance W preferably satisfy the relationship 1≦W / t≦10, and more preferably 2≦W / t≦6. By appropriately setting the ratio W / t in this way, poor rubber flow during tire vulcanization can be suppressed, thereby effectively improving crack resistance. Note that the maximum thickness t of the transponder includes the thickness of the covering layer if the transponder is covered with a covering layer.

[0028] Fig. 3 shows a modified example of a pneumatic tire according to an embodiment of the present invention. As shown in Fig. 3, the bead filler 6 includes a first bead filler 6A arranged adjacent to the bead core 5 on the radially outer side of the tire, and a second bead filler 6B arranged adjacent to the first bead filler 6A on the radially outer side of the tire. The first bead filler 6A and the second bead filler 6B are preferably made of rubbers having different physical properties.

[0029] For such a bead filler 6, it is preferable that the transponder 20 be disposed between the second bead filler 6B and the carcass layer 4. By disposing the transponder 20 between the second bead filler 6B and the carcass layer 4, the transponder 20 is closer to the outer surface of the sidewall portion 2 than when disposed in the first bead filler 6A, and therefore the communication performance of the transponder 20 can be effectively improved.

[0030] In particular, when the transponder 20 is disposed between the second bead filler 6B and the carcass layer 4, it is preferable that the hardness of the second bead filler 6B be lower than the hardness of the first bead filler 6A. Furthermore, it is preferable that the hardness of the second bead filler 6B be in the range of 55 to 65. Since the second bead filler 6B in which the transponder 20 is embedded is made of a relatively soft rubber, the second bead filler 6B absorbs impacts and makes it difficult for the impacts to be transmitted to the transponder 20. This makes it possible to prevent damage to the transponder 20. Note that in the present invention, the hardness of the bead filler 6 is a durometer hardness specified in JIS K6253, and is a hardness (JIS hardness) measured at a temperature of 20°C using a type A durometer.

[0031] Furthermore, the transponder 20 is preferably disposed radially outward of the turned-up end 4e of the carcass layer 4. In particular, the transponder 20 is preferably disposed at a distance of 10 mm or more radially outward of the turned-up end 4e of the carcass layer 4. By disposing the transponder 20 at a distance from the turned-up end 4e of the carcass layer 4 in this manner, the communication performance of the transponder 20 can be sufficiently ensured. Furthermore, since the transponder 20 is disposed so that the step of the turned-up end 4e of the carcass layer 4 and the step of the transponder 20 do not overlap, the amount of the step is reduced, and cracks on the tire surface due to poor rubber flow can be suppressed. In contrast, in heavy-duty tires, carcass cords are generally made of metal cords, and if such metal members are disposed radially outward of the transponder, the communication performance of the transponder tends to deteriorate.

[0032] Fig. 4 shows another modified example of a pneumatic tire according to an embodiment of the present invention. While Fig. 3 shows an example in which the transponder 20 is embedded in the approximate center of the bead filler 6 in the tire radial direction, Fig. 4 shows an example in which the transponder 20 is embedded in the bead filler 6 at a relatively high position in the tire radial direction.

[0033] As shown in Fig. 4, the bead filler 6 includes a first bead filler 6A and a second bead filler 6B. For such a bead filler 6, the transponder 20 is preferably arranged radially outward of the tire radially outer end (upper end) of the metal reinforcing layer 11. By arranging the transponder 20 in this manner, the transponder 20 is arranged at a distance from the metal member, thereby effectively improving the communication performance of the transponder 20. Furthermore, since the transponder 20 is arranged so that the step of the turned-up end 4e of the carcass layer 4 and the step of the transponder 20 do not overlap, the amount of the step is reduced, and it is possible to suppress the occurrence of cracks on the tire surface due to poor rubber flow.

[0034] 5 and 6 show another modified example of a pneumatic tire according to an embodiment of the present invention. As shown in FIGS. 5 and 6, the entire transponder 20 is covered with a covering layer 23 made of rubber. The covering layer 23 has a surface 23a that contacts the carcass layer 4 and a surface 23b that contacts the bead filler 6, and the widths w1 and w2 of these surfaces 23a and 23b are different from each other. Therefore, a step 24 is formed in the covering layer 23 so as to extend in the longitudinal direction. The transponder 20 covered with the covering layer 23 is composed of an IC substrate and spiral antennas that protrude from both ends of the IC substrate.

[0035] In such a covering layer 23, it is preferable that the absolute value |w1-w2| of the difference between the width w1 on the side in contact with the carcass layer 4 and the width w2 on the side in contact with the bead filler 6 is set to be 0.2 mm or more. By appropriately setting the absolute value |w1-w2| of the difference in this way, the amount of step around the transponder 20 can be reduced, thereby effectively improving crack resistance. Furthermore, the shape of the covering layer 23 can be stabilized, thereby effectively improving the communication performance of the transponder 20.

[0036] 5 and 6 show an example in which the width w1 of the side in contact with the carcass layer 4 is wider than the width w2 of the side in contact with the bead filler 6, but the width w2 may be wider than the width w1. Also, although an example in which the step 24 is formed on only one side in the width direction of the covering layer 23 is shown, the step 24 may be formed on both sides in the width direction of the covering layer 23. Furthermore, if necessary, the step 24 can also be provided on the end portions of the covering layer 23 in the longitudinal direction.

[0037] The coating layer 23 also has layers 23x and 23y in its thickness direction. The layers 23x and 23y are separated in the thickness direction of the coating layer 23 by the center line of the transponder 20. When forming the coating layer 23 having the cross-sectional shape shown in FIGS. 6(a) and 6(b), two layers 23x and 23y having rectangular cross-sectional shapes and different widths are used, and these layers 23x and 23y are stacked so that the widthwise ends of one side of these layers 23x and 23y coincide with each other to cover the entire transponder 20. This allows a step 24 to be formed at the widthwise end of the other side of the stacked coating layer 23. Alternatively, one coating layer 23 having a rectangular cross-sectional shape may be used and folded to cover the entire transponder 20. As an alternative method, two coating layers 23 having the same width and rectangular cross-sectional shape may be used, stacked to cover the entire transponder 20, and then the step 24 may be formed by removing at least one widthwise end of the stacked coating layer 23. [Example]

[0038] A tire size of 275 / 80R22.5 was manufactured. The tire had a circumferentially extending annular tread portion, a pair of sidewall portions disposed on either side of the tread portion, and a pair of bead portions disposed radially inward of the sidewall portions. A bead filler was disposed on the outer periphery of the bead core of each bead portion, and a carcass layer was mounted between the pair of bead portions. The carcass layer was wound up around the bead core from the inside to the outside of the tire. In this pneumatic tire, a transponder (RFID tag) was embedded between the bead filler and the carcass layer. Tires of the conventional example and examples 1 to 11 were manufactured with the distance W, ratio W / t, placement between the carcass layer and the second bead filler, hardness of the second bead filler, material of the carcass cord, presence or absence of a metal reinforcing layer, placement above the top end of the metal reinforcing layer, placement above the carcass wrap-up end, and absolute value of the difference |w1-w2| set as shown in Tables 1 and 2.

[0039] In the conventional example and Examples 1 to 11, the hardness (JIS hardness) of the first bead filler is set to 70.

[0040] The tag communication properties and crack resistance of these test tires were evaluated using the following test methods, and the results are shown in Tables 1 and 2.

[0041] Tag communication: For each test tire, a reader / writer was used to communicate with the tag. Specifically, the longest communication distance was measured using the reader / writer with an output of 250 mW and a carrier frequency of 860 MHz to 960 MHz. The evaluation results were expressed as an index, with the conventional example being set at 100. The higher the index value, the better the tag's communication performance.

[0042] Crack Resistance: Each test tire was mounted on a standard rim wheel, and the air pressure was adjusted to 70% of the specified maximum air pressure. A running test was conducted using a drum testing machine under the specified maximum load, a speed of 48 km, and a distance of 10,000 km. The depth of cracks in the sidewall at the tag embedding position was then measured. The evaluation results were expressed as an index using the reciprocal of the measurement value, with the conventional example being set at 100. The higher the index value, the better the tire's crack resistance.

[0043] [Table 1]

[0044] [Table 2]

[0045] As can be seen from Tables 1 and 2, the pneumatic tires of Examples 1 to 11 were able to improve the crack resistance of the tires while improving the tag communication performance compared to the conventional example.

[0046] The present disclosure includes the following inventions [1] to [9]. Invention [1] is a pneumatic tire having a tread portion extending circumferentially in a ring shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged radially inward of the sidewall portions, in which a bead filler is arranged on the outer periphery of the bead core of each bead portion, a carcass layer is mounted between the pair of bead portions, and the carcass layer is wound up around the bead core from the inside to the outside of the tire, wherein a transponder is embedded between the bead filler and the carcass layer, and the distance W measured in the normal direction of the carcass layer from the outer surface of the transponder to the outer surface of the bead filler is in the range of 2 mm to 20 mm. Invention [2] is the pneumatic tire according to invention [1], characterized in that the maximum thickness t [mm] of the transponder and the distance W satisfy the relationship 1≦W / t≦10. Invention [3] is a pneumatic tire according to invention [1] or [2], characterized in that the bead filler is composed of a first bead filler arranged adjacent to the bead core on the radially outer side of the tire, and a second bead filler arranged adjacent to the first bead filler on the radially outer side of the tire, and the transponder is arranged between the second bead filler and the carcass layer. Invention [4] is the pneumatic tire according to invention [3], characterized in that the hardness of the second bead filler is lower than the hardness of the first bead filler and is in the range of 55 to 65. Invention [5] is the pneumatic tire according to any one of inventions [1] to [4], characterized in that the carcass cords constituting the carcass layer are metal cords. Invention [6] is the pneumatic tire according to any one of inventions [1] to [5], characterized in that a metal reinforcing layer is disposed on the outer side of the carcass layer in the bead portion. Invention [7] is a pneumatic tire according to invention [6], characterized in that the metal reinforcing layer is wound up around the bead core from the inside to the outside of the tire, and the transponder is positioned radially outward of the wound-up end of the metal reinforcing layer. Invention [8] is a pneumatic tire according to any one of inventions [1] to [7], characterized in that the transponder is arranged radially outward of the turned-up end of the carcass layer. Invention [9] is a pneumatic tire according to any one of inventions [1] to [8], characterized in that the entire transponder is covered with a covering layer made of rubber, and the absolute value of the difference between the width w1 of the covering layer on the side in contact with the carcass layer and the width w2 of the covering layer on the side in contact with the bead filler, |w1-w2|, is 0.2 mm or more. [Explanation of symbols]

[0047] 1 Tread section 2 Sidewall 3 Bead section 4 carcass layers 4e Rolled up end 5 bead core 6 Bead filler 6A First bead filler 6B Second bead filler 6e Tire radial outer edge 7 Belt Layer 10 Reinforcement layer 11 Metal reinforcement layer 12 Non-metallic reinforcement layer 13 Sidewall rubber layer 14 Rim cushion rubber layer 20 Transponder CL Tire centerline

Claims

1. A pneumatic tire having a structure comprising a tread portion extending in the tire circumferential direction and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed radially inward of the sidewall portions, wherein a bead filler is disposed on the outer periphery of a bead core of each bead portion, and a carcass layer is mounted between the pair of bead portions, and the carcass layer is wound up around the bead core from the inside to the outside of the tire, A pneumatic tire characterized in that a transponder is embedded between the bead filler and the carcass layer, and a distance W measured in a normal direction of the carcass layer from an outer surface of the transponder to an outer surface of the bead filler is in a range of 2 mm to 20 mm.

2. 2. The pneumatic tire according to claim 1, wherein the maximum thickness t [mm] of the transponder and the distance W satisfy the relationship 1≦W / t≦10.

3. 3. The pneumatic tire according to claim 1, wherein the bead filler is composed of a first bead filler arranged adjacent to the bead core on the radially outer side of the tire, and a second bead filler arranged adjacent to the first bead filler on the radially outer side of the tire, and the transponder is arranged between the second bead filler and the carcass layer.

4. 4. The pneumatic tire according to claim 3, wherein the hardness of the second bead filler is lower than the hardness of the first bead filler and is in the range of 55 to 65.

5. 3. The pneumatic tire according to claim 1, wherein the carcass cords constituting the carcass layer are metal cords.

6. 3. The pneumatic tire according to claim 1, wherein a metal reinforcing layer is disposed on the outer side of the carcass layer in the bead portion.

7. 7. The pneumatic tire according to claim 6, wherein the metal reinforcing layer is wound up around the bead core from the inside to the outside of the tire, and the transponder is disposed radially outward of the wound-up end of the metal reinforcing layer.

8. 3. The pneumatic tire according to claim 1, wherein the transponder is disposed radially outward of the turned-up end of the carcass layer.

9. The pneumatic tire according to claim 1 or 2, characterized in that the entire transponder is covered with a covering layer made of rubber, and the absolute value |w1-w2| of the difference between the width w1 of the covering layer on the side in contact with the carcass layer and the width w2 of the covering layer on the side in contact with the bead filler is 0.2 mm or more.

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