Pneumatic tire

Abstract

To provide a pneumatic tire configured so that a transponder can be prevented from being damaged and durability 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. At least a portion of a transponder 20 is buried inside the bead filler 6.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 makes it possible to improve the durability of the tire while preventing damage to the transponder. [Background technology]

[0002] It has been proposed to embed an RFID tag (transponder) in a pneumatic tire (see, for example, Patent Document 1). However, depending on the location where the transponder is embedded in the tire, there is a problem that the transponder may be damaged or the durability of the tire may be reduced. [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 durability of the tire while preventing damage to 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 of the tire to form an annular shape, 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, and wherein at least a portion of a transponder is embedded inside the bead filler. [Effects of the Invention]

[0006] In the present invention, at least a portion of the transponder is embedded inside the bead filler. The bead filler is a member that deforms little even when a load is applied to the tire, so by disposing at least a portion of the transponder inside such a bead filler, damage to the transponder can be prevented. By preventing damage to the transponder, damage to the inside of the tire at the location where the transponder is embedded can be avoided, thereby improving the durability of the tire.

[0007] In the pneumatic tire of the present invention, it is preferable that the entire transponder is disposed inside the bead filler, which makes it possible to more effectively prevent damage to the transponder and thereby to obtain a sufficient improvement effect on the durability of the tire.

[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 inside the second bead filler, 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 preferably lower than that of the first bead filler and is in the range of 55 to 65. By using a relatively soft rubber for the second bead filler in which the transponder is embedded, the second bead filler absorbs impacts and makes them less likely to be transmitted to the transponder. This makes it possible to more effectively prevent damage to the transponder and to obtain a sufficient improvement in tire durability.

[0010] The carcass cords constituting the carcass layer are preferably metal cords, which are suitable for use in heavy-duty tires for trucks and buses, and can effectively improve the durability of the tire.

[0011] The transponder is preferably disposed radially outward from the wound-up end of the carcass layer. For example, when the tire is used as a heavy-duty tire, the carcass cord is generally made of a metal cord, so disposing the transponder away from the wound-up end of the carcass layer can sufficiently ensure communication performance of the transponder.

[0012] The transponder is disposed at a distance of 25 mm or more from the center of the bead core outward in the tire radial direction, and the ratio of the height from the center of the bead core to the end of the second bead filler on the outer side in the tire radial direction is preferably 50% or more. This brings the transponder closer to the part of the sidewall where the rubber thickness is thin, thereby effectively improving the communication performance of the transponder.

[0013] It is preferable that a reinforcing layer is disposed on the outer side of the bead filler in the tire width direction, and the transponder is disposed radially outward of the outer end of the reinforcing layer in the tire radial direction, thereby preventing radio waves from being blocked by the reinforcing layer during communication by the transponder, thereby effectively improving the communication performance of the transponder.

[0014] The transponder is preferably disposed on the outer side in the tire width direction of the center line of the bead filler in the tire width direction, which brings the transponder closer to the outer surface of the sidewall portion than when the transponder is disposed on the inner side in the tire width direction of the center line of the bead filler, thereby effectively improving the communication performance of the transponder.

[0015] The transponder is preferably located at the splice of the bead filler, which allows the transponder to be located at any desired position on the bead filler. [Brief explanation of the drawings]

[0016] [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. 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 3] 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 4] 5(a) to 5(c) are cross-sectional views showing the main parts of other modified examples of the pneumatic tire according to the embodiment of the present invention. [Figure 5] FIG. 2 is an explanatory diagram showing the embedded positions of transponders in a test tire. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 shows a pneumatic tire according to an embodiment of the present invention;

[0018] 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.

[0019] At least one carcass layer 4 (one layer in FIG. 1) made of a plurality of carcass cords arranged in the radial direction is mounted between the pair of bead portions 3. The carcass cords making up the carcass layer 4 are preferably metal cords such as steel cords, which are suitable for use in heavy-duty tires and contribute to improving the durability of the tire. 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.

[0020] 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.

[0021] In the pneumatic tire described above, the turned-up end 4e of the carcass layer 4 is disposed radially inward of 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 middle 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 a plurality of metal cords (e.g., steel cords), and at least one non-metal reinforcing layer 12 (two layers in FIG. 1 ) containing a plurality of organic fiber cords and disposed outward of the metal reinforcing layer 11 in the tire width direction. 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.

[0022] 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.

[0023] In the pneumatic tire, at least a portion of the transponder 20 is embedded inside the bead filler 6. In Fig. 1, a portion of the transponder 20 is embedded inside the bead filler 6, and the remainder is embedded in the sidewall rubber layer 13. Alternatively, a portion of the transponder 20 may be embedded inside the bead filler 6, and the remainder may be embedded in the rim cushion rubber layer 14. The transponder 20 is arranged to extend along the tire circumferential direction.

[0024] The present invention includes a configuration in which at least a portion of the transponder 20 is embedded inside the bead filler 6, but this does not include a case in which the transponder 20 is disposed between (at the interface between) the carcass layer 4 and the bead filler 6, a case in which the transponder 20 is disposed between (at the interface between) the bead core 5 and the bead filler 6, a case in which the transponder 20 is disposed between (at the interface between) the bead filler 6 and the sidewall rubber layer 13, or a case in which the transponder 20 is disposed between (at the interface between) the bead filler 6 and the rim cushion rubber layer 14. In this way, the present invention assumes a configuration in which at least a portion of the transponder 20 is embedded inside the bead filler 6, rather than the entire transponder 20 being disposed at the interface between the bead filler 6 and another member.

[0025] 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.

[0026] 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.

[0027] In the pneumatic tire described above, at least a portion of the transponder 20 is embedded inside the bead filler 6. The bead filler 6 is a member that deforms little even when a load is applied to the tire, and therefore, by disposing at least a portion of the transponder 20 inside such a bead filler 6, it is possible to prevent damage to the transponder 20. By preventing damage to the transponder 20, it is possible to avoid damage to the inside of the tire at the location where the transponder 20 is embedded, and therefore it is possible to improve the durability of a pneumatic tire with the transponder 20 embedded therein.

[0028] In particular, it is preferable that the entire transponder 20 is disposed inside the bead filler 6. By embedding the entire transponder 20 inside the bead filler 6 in this way, damage to the transponder 20 can be more effectively prevented, and the durability of the tire can be sufficiently improved.

[0029] Fig. 2 shows a modified example of a pneumatic tire according to an embodiment of the present invention. As shown in Fig. 2, 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.

[0030] For such a bead filler 6, it is preferable that the entire transponder 20 is disposed inside the second bead filler 6B. By disposing the transponder 20 inside the second bead filler 6B, 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.

[0031] In particular, when the transponder 20 is disposed inside the second bead filler 6B, 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 more effectively prevent damage to the transponder 20, and to sufficiently improve the durability of the tire. Note that in the present invention, the hardness of the bead filler 6 is the durometer hardness specified in JIS K6253, and is the hardness (JIS hardness) measured at a temperature of 20°C using a type A durometer.

[0032] Furthermore, it is preferable that the transponder 20 be disposed radially outward of the turned-up end 4e of the carcass layer 4. This means that the radially inner end (lowest end) of the transponder 20 is positioned radially outward of the tire beyond the turned-up end 4e of the carcass layer 4. In particular, it is preferable that the transponder 20 be disposed 10 mm or more away from the turned-up end 4e of the carcass layer 4 radially outward of the tire. By disposing the transponder 20 away 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. On the other hand, in the case of heavy-duty tires, the carcass cord is generally made of a metal cord, and therefore, if such a metal member is disposed radially outward of the transponder, the communication performance of the transponder tends to deteriorate.

[0033] The transponder 20 is preferably disposed at a distance of 25 mm or more from the center of the bead core 5 outward in the tire radial direction. Furthermore, the ratio H1 / H2×100 [%] of the height H1 (see FIG. 2) from the center of the bead core 5 to the radially inner end (lowest end) of the transponder 20 and the height H2 (see FIG. 2) from the center of the bead core 5 to the radially outer end 6e of the second bead filler 6B is preferably 50% or more. That is, the transponder 20 is preferably disposed so that the height H1 is 25 mm or more and is located radially outward from the position of 0.5×H2. The center of the bead core 5 is the intersection of the diagonals of an imaginary rectangle connecting the center points of four wires constituting the bead core 5, when the wire with the largest area of ​​the imaginary rectangle is selected.

[0034] By appropriately setting the position of the transponder 20 in the tire radial direction in this way, the transponder 20 is brought closer to the part of the sidewall portion 2 where the rubber thickness is thin, so that the communication performance of the transponder 20 can be effectively improved.

[0035] Fig. 3 shows another modified example of a pneumatic tire according to an embodiment of the present invention. While Fig. 2 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. 3 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.

[0036] As shown in FIG. 3 , 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 disposed radially outward of the radially outer end (upper end) of the reinforcing layer 10. This upper end of the reinforcing layer 10 may be the upper end of either the metal reinforcing layer 11 or the non-metal reinforcing layer 12, and refers to the end located radially outward of the bead filler 6 in the tire width direction. In FIG. 3 , this corresponds to the upper end of the non-metal reinforcing layer 12 located radially outward. By disposing the transponder 20 in this manner, radio waves transmitted by the transponder 20 during communication are not blocked by the reinforcing layer 10, effectively improving the communication performance of the transponder 20.

[0037] Furthermore, it is preferable that the transponder 20 is disposed on the outer side in the tire width direction of the center line L of the bead filler 6 in the tire width direction. This brings the transponder 20 closer to the outer surface of the sidewall portion 2 than when the transponder 20 is disposed on the inner side in the tire width direction of the center line L of the bead filler 6, thereby effectively improving the communication performance of the transponder 20. Note that the center line L is a line (curve) formed by connecting the center positions of the bead fillers 6 in the width direction, following the shape of the bead filler 6. If the transponder is disposed so that this center line overlaps with the transponder, the above configuration is not satisfied.

[0038] 4(a) to 4(c) show other modified examples of the pneumatic tire according to the embodiment of the present invention. In Fig. 4(a) to 4(c), Tr indicates the tire radial direction, Tc indicates the tire circumferential direction, and Tw indicates the tire width direction.

[0039] When a green tire is molded, the bead filler 6 is formed by connecting multiple rubber parts with triangular cross sections in the tire circumferential direction. When molding the green tire, as shown in FIG. 4( a), the rubber parts 611 and 612 that make up the bead filler 6 are arranged adjacent to each other in the tire circumferential direction, and the transponder 20 is arranged between the rubber parts 611 and 612 so as to extend along the tire radial direction. At this time, the transponder 20 may be covered with rubber or may not be covered with rubber. Next, as shown in FIG. 4( b), the rubber parts 611 and 612 are connected, and the transponder 20 is arranged at the splice portion S between the rubber parts 611 and 612. By vulcanizing the green tire with the transponder 20 arranged in this manner in a vulcanization process, a pneumatic tire in which the transponder 20 is embedded inside the bead filler 6 can be manufactured. In this pneumatic tire, the transponder 20 is arranged so as to extend along the tire radial direction, as shown in FIG. 4( c). This allows the transponder 20 to be placed at any position on the bead filler 6. [Example]

[0040] A pneumatic tire having a tire size of 275 / 80R22.5, comprising a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the tire radially inward of these sidewall portions, in which a bead filler is disposed 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, the tire having a transponder (RFID tag) inside the tire. The conventional tire and tires according to Examples 1 to 10 were manufactured with a tag embedded in the bead filler, and the tag embedding position, placement of at least a portion of the tag inside the bead filler, placement of the entire tag inside the bead filler, placement inside the second bead filler, hardness of the second bead filler, material of the carcass cord, placement above the carcass wrap-up end, height H1 (25 mm or more), H1 / H2 x 100, placement above the top end of the reinforcing layer, placement outside the center line of the bead filler, and placement at the splice portion of the bead filler set as shown in Table 1.

[0041] Note that A to G and X shown in "Tag embedding position" in Table 1 correspond to the tag positions shown in Figure 5. Regarding "Height H1" in Table 1, if the height H1 is 25 mm or more, it is indicated as "present," and if the height H1 is less than 25 mm, it is indicated as "absent." Furthermore, in the conventional example, the transponder is disposed between the carcass layer and the bead filler (at the interface), so it is not considered that part or all of the transponder is disposed inside the bead filler. In the conventional example and Examples 1 to 10, the hardness (JIS hardness) of the first bead filler is set to 80.

[0042] The tag communication properties and tire durability of these test tires were evaluated using the following test methods, and the results are shown in Table 1.

[0043] 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.

[0044] Tire durability: Each test tire was mounted on a standard rim wheel, the air pressure adjusted to the maximum standard pressure, the load set to the maximum standard load, and a running test was conducted using a drum testing machine at a speed of 48 km / h. The running distance when the tire failed was measured. The evaluation results were expressed as an index, with the conventional example being set at 100. The higher the index value, the better the tire's durability.

[0045] [Table 1]

[0046] As can be seen from Table 1, the pneumatic tires of Examples 1 to 10 were able to improve the tag communication performance and tire durability compared to the conventional example.

[0047] The present disclosure includes the following inventions [1] to

[10] . 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 this carcass layer is wound up around the bead core from the inside to the outside of the tire, and at least a part of a transponder is embedded inside the bead filler. Invention [2] is the pneumatic tire according to invention [1], characterized in that the transponder is entirely disposed inside the bead filler. 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 inside the second bead filler. 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 a pneumatic tire according to any one of inventions [1] to [5], characterized in that the transponder is arranged radially outward of the turned-up end of the carcass layer. Invention [7] is a pneumatic tire according to invention [3] or [4], characterized in that the transponder is positioned at a distance of 25 mm or more from the center of the bead core radially outward of the tire, and the ratio of the height from the center of the bead core to the transponder to the height from the center of the bead core to the radially outer end of the second bead filler is 50% or more. Invention [8] is a pneumatic tire according to any one of inventions [1] to [7], characterized in that a reinforcing layer is arranged on the tire width direction outer side of the bead filler, and the transponder is arranged on the tire radial direction outer side of the tire radial direction outer end of the reinforcing layer. Invention [9] is a pneumatic tire according to any one of inventions [1] to [8], characterized in that the transponder is arranged on the outer side in the tire width direction of the center line of the bead filler in the tire width direction. Invention

[10] is the pneumatic tire according to any one of inventions [1] to [9], characterized in that the transponder is disposed in a splice portion of the bead filler. [Explanation of symbols]

[0048] 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 circumferentially in a ring shape and extending in the tire circumferential direction, 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, wherein a bead filler is arranged on the outer periphery of a 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 at least a portion of a transponder is embedded inside the bead filler.

2. 2. The pneumatic tire according to claim 1, wherein the transponder is disposed entirely within the bead filler.

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 inside the second bead filler.

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 the transponder is disposed radially outward of the turned-up end of the carcass layer.

7. 4. The pneumatic tire according to claim 3, wherein the transponder is disposed 25 mm or more away from the center of the bead core radially outward of the tire, and a ratio of a height from the center of the bead core to the transponder relative to a height from the center of the bead core to an end of the second bead filler radially outward of the tire is 50% or more.

8. 3. The pneumatic tire according to claim 1, wherein a reinforcing layer is disposed on the outer side of the bead filler in the tire width direction, and the transponder is disposed on the outer side of an outer end of the reinforcing layer in the tire radial direction.

9. 3. The pneumatic tire according to claim 1, wherein the transponder is disposed on an outer side in the tire width direction from a center line of the bead filler in the tire width direction.

10. 3. The pneumatic tire according to claim 1, wherein the transponder is disposed at a splice portion of the bead filler.

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