Tire manufacturing method

Abstract

To provide a tire manufacturing method, which can manufacture a tire having a conductive pass secured, while reducing rolling resistance of the tire.SOLUTION: A tire manufacturing method according to the present invention manufactures a tire comprising two carcass plies in which carcass cords cross each other between layers, where a loss tangent tanδ at 60°C of a coating rubber of the carcass plie is 0.1 or less. The method includes a first step in which a first carcass member is arranged on a tire molding drum, and a second step in which a second carcass member and a conductive rubber member are arranged on the tire molding drum so that the second carcass member is positioned at the tire molding drum side and the conductive rubber member is positioned at an opposite side of the tire molding drum, with the conductive rubber member arranged on the second carcass member, after the first step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a tire. [Background technology]

[0002] 2. Description of the Related Art Conventionally, tire structures have been proposed in which a conductive member is disposed in a tire to form a conductive path from the vehicle body to the road surface, thereby dissipating static electricity from the vehicle body to the road surface (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-203631 A [Patent Document 2] Patent Publication No. 2021-000892 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, a tire structure in which two carcass plies are arranged so that the carcass cords cross each other has been proposed as a tire suitable for high-speed driving such as circuit driving. In addition, in recent years, there has been a demand for using rubber with low rolling resistance as the covering rubber for the carcass ply in order to reduce the rolling resistance of the tire.

[0005] However, low rolling resistance rubber generally has a high electrical resistivity, and if low rolling resistance coated rubber is used for the carcass ply of the carcass structure described above, there is a possibility that a conductive path from the vehicle body to the road surface cannot be secured.

[0006] Therefore, an object of the present invention is to provide a tire manufacturing method capable of manufacturing a tire in which a conductive path is ensured while reducing the rolling resistance of the tire. [Means for solving the problem]

[0007] The gist and configuration of the present invention are as follows. (1) A method for manufacturing a tire having two carcass plies in which the carcass cords cross each other between the plies, comprising the steps of: The covering rubber of the carcass ply has a loss tangent tanδ of 0.1 or less at 60°C, A first step of placing a first carcass member on a tire building drum; a second step of, after the first step, arranging a conductive rubber member on a second carcass member, and then arranging the second carcass member and the conductive rubber member on the tire building drum so that the second carcass member faces the tire building drum and the conductive rubber member faces the opposite side of the tire building drum. Here, the term "loss tangent tan δ at 60° C." refers to the loss tangent measured using a spectrometer under the conditions of an atmospheric temperature of 60° C., a dynamic strain of 1%, and a frequency of 52 Hz.

[0008] (2) In the first step, a first conductive member is further disposed on the first carcass member on a side opposite to the tire building drum, The tire is The tire has a bead core embedded in a pair of bead portions, The first carcass ply formed by the first carcass member includes a first carcass body portion toroidally straddling the pair of bead portions, and a first carcass folded-up portion extending from the first carcass body portion and folded-up around the bead core, the first conductive member includes a first main body portion that spans the pair of bead portions in a toroidal shape, and a first folded-back portion that extends from the first main body portion and is folded back around the bead core, The method for manufacturing a tire described in (1), wherein an end of the first carcass folded portion and an end of the first folded portion are located radially outward of the tire radially inner end of the conductive rubber member.

[0009] (3) In the first step, a first conductive member is further disposed on the first carcass member on a side opposite to the tire building drum, The tire is The tire has a bead core embedded in a pair of bead portions, The first carcass ply formed by the first carcass member includes a first carcass body portion toroidally straddling the pair of bead portions, and a first carcass folded-up portion extending from the first carcass body portion and folded-up around the bead core, the first conductive member includes a first main body portion that spans the pair of bead portions in a toroidal shape, and a first folded-back portion that extends from the first main body portion and is folded back around the bead core, The tire manufacturing method described in (1), wherein an end of the first carcass folded portion and an end of the first folded portion are located more inward in the tire width direction than an outer end of the conductive rubber member in the tire width direction.

[0010] (4) The method for manufacturing a tire according to any one of (1) to (3), wherein the carcass cord of the carcass ply of the tire is inclined at an angle of 80° to 88° with respect to the tire circumferential direction.

[0011] (5) The conductive rubber member has a volume resistivity of 1.0×10 9 The method for producing a tire according to any one of (1) to (4), wherein the elastic modulus is Ω·cm or less. Effect of the Invention

[0012] According to the present invention, it is possible to provide a tire manufacturing method capable of manufacturing a tire in which the rolling resistance of the tire is reduced while ensuring a conductive path. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a first example of a tire structure. [Diagram 2] FIG. 2 is a schematic diagram for explaining a first step and a second step. [Diagram 3] FIG. 4 is a diagram illustrating a second example of a tire structure. [Figure 4] FIG. 4 is a diagram illustrating a third example of a tire structure. [Diagram 5] FIG. 1 is a diagram for explaining the arrangement of RFIDs. [Figure 6] FIG. 1 is a diagram for explaining the arrangement of RFIDs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] <Tires> First, a tire manufactured by a tire manufacturing method according to one embodiment of the present invention will be described. Fig. 1 is a diagram showing a first example of a tire structure. In the diagram, only one half in the tire width direction with the tire equatorial plane as a boundary is shown, but the other half has the same structure.

[0016] As shown in FIG. 1, the tire 1 includes a pair of bead portions 2, a pair of sidewall portions (not shown) continuing to the pair of bead portions 2, and a tread 3 continuing between the pair of sidewall portions.

[0017] A bead core 2a is embedded in each of the pair of bead portions 2. Although not shown in the figure, a bead filler can be disposed on the outer side of the bead core 2a in the tire radial direction. In the illustrated example, the tread 3 is made up of a cap rubber 3a and a base rubber 3b located on the inner side of the cap rubber in the tire radial direction. On the other hand, the tread 3 can also be a single layer.

[0018] The tire 1 further includes a carcass 4 that spans a pair of bead portions 2 in a toroidal shape. The carcass 4 includes two carcass plies 4a, 4b in which carcass cords cross each other between layers. The carcass plies 4a, 4b are formed by covering the carcass cords with a covering rubber. The carcass cords are not particularly limited, but may be, for example, organic fiber cords. The carcass cords are preferably inclined at an angle of 80° to 88° with respect to the tire circumferential direction. In this way, by configuring the carcass cords inclined at a high angle with respect to the tire circumferential direction to cross each other between layers, the rigidity in the tire rotation direction can be improved, and the grip performance of the tire can be improved. The covering rubber of the carcass ply has a loss tangent tanδ of 0.1 or less at 60°C. By setting the loss tangent tanδ of the covering rubber of the carcass ply to 0.1 or less at 60°C, the rolling resistance of the tire can be reduced. On the other hand, from the viewpoint of ensuring fracture resistance, the loss tangent tanδ of the covering rubber of the carcass ply at 60°C is preferably 0.05 or more. The carcass ply 4a located on the inner side in the tire radial direction in the crown portion is composed of a first carcass body portion 4a1 that spans a pair of bead portions 2 in a toroidal shape, and a first carcass folded-up portion 4a2 that extends from the first carcass body portion 4a1 and is folded back around the bead core 2a. Similarly, the carcass ply 4b located on the outer side in the tire radial direction in the crown portion is composed of a second carcass body portion 4b1 that spans a pair of bead portions 2 in a toroidal shape, and a second carcass folded-up portion 4b2 that extends from the second carcass body portion 4b1 and is folded back around the bead core 2a. From the viewpoint of improving the rigidity of the tire sidewall portion, the ends of the first and second carcass folded-up portions 4a2, 4b2 are preferably positioned radially outward of the radially outer ends of the bead fillers.

[0019] In the illustrated example, the tire 1 includes a belt 5 on the tire radial outside of the crown portion of the carcass 4. The belt 5 is made of two belt layers 5a and 5b. Each of the belt layers 5a and 5b is made of a belt ply, and the belt ply is made of a belt cord covered with a belt covering rubber. The belt cord is not particularly limited, but may be inclined at an inclination angle of 20 to 40° with respect to the tire circumferential direction, for example. It is preferable that the belt cords cross each other between the layers. The loss tangent tanδ of the belt covering rubber at 60°C is preferably 0.12 to 0.2. By making the loss tangent tanδ of the belt covering rubber at 60°C 0.12 or more, it is possible to ensure fracture resistance, while by making the loss tangent tanδ of the belt covering rubber at 60°C 0.2 or less, it is possible to reduce rolling resistance. The volume resistivity of the belt covering rubber is 1.0×10 9 It is preferable that the elastic modulus is Ω·cm or less. In the illustrated example, the width in the tire width direction of the belt layer 5a on the inner side in the tire radial direction is larger than the width in the tire width direction of the belt layer 5b on the outer side in the tire radial direction. On the other hand, the belt structure such as the number of belt layers, the inclination angle of the belt cord, and the width in the tire width direction of the belt layer can be various and is not limited to this example.

[0020] In the illustrated example, the tire 1 includes a belt reinforcing layer 6, one layer in the illustrated example, on the tire radial direction outer side of the belt 5. The belt reinforcing layer 6 is made of a belt reinforcing layer ply, and the belt reinforcing layer ply is formed by covering a belt reinforcing layer cord with a belt reinforcing layer covering rubber. The belt reinforcing layer cord is not particularly limited, but may extend in the tire circumferential direction, for example. The loss tangent tan δ of the belt reinforcing layer covering rubber at 60°C is preferably 0.12 to 0.2. By making the loss tangent tan δ of the belt reinforcing layer covering rubber at 60°C 0.12 or more, it is possible to ensure fracture resistance, while by making the loss tangent tan δ of the belt reinforcing layer covering rubber at 60°C 0.2 or less, it is possible to reduce rolling resistance. The volume resistivity of the belt reinforcing layer covering rubber is 1.0×10 9It is preferable that the elastic modulus is Ω·cm or less. In the illustrated example, the width of the belt reinforcing layer 6 in the tire width direction is larger than the width of the belt layers 5a, 5b in the tire width direction. On the other hand, the reinforcing layer structure, such as the number of layers of the belt reinforcing layer, the inclination angle of the belt reinforcing layer cord, and the width of the belt reinforcing layer in the tire width direction, can be various and is not limited to this example.

[0021] As shown in FIG. 1, the tire 1 further includes a conductive rubber member 7 on the tire radial outer side of the crown portion of the carcass 4 and on the tire radial inner side of the belt 5. In the illustrated example, the conductive rubber member 7 is composed of a conductive rubber member main body portion 7a that extends from the tire radial outer side of the crown portion of the carcass 4 and the tire radial inner side of the belt 5, and toroidally straddles a pair of bead portions 2, and a conductive rubber member folded-back portion 7b that extends from the conductive rubber member main body portion 7a and is folded back around the bead core and terminates. In this example, the end of the conductive rubber member folded-back portion 7b is located on the tire radial inner side of the tire radial outer end of the bead core 2a, and thus, while establishing a conductive path as described later, the extension length can be made as small as possible, thereby making the tire lighter. The volume resistivity of the conductive rubber member 7 is 1.0×10 9 It is preferable that the loss tangent tanδ of the conductive rubber member 7 at 60°C is 0.2 or less, because this increases the conductivity and allows static electricity to escape to the road surface more reliably through the conductive path. On the other hand, from the viewpoint of reducing the rolling resistance as much as possible, it is preferable that the loss tangent tanδ of the conductive rubber member 7 at 60°C is 0.2 or less.

[0022] The tire 1 further includes a carcass chafer 8 around the bead core 2a (on the outer circumferential side of the carcass 4). In the region on the inner side in the tire radial direction of the bead core 2a, a part of the conductive rubber member 7 seeps out by flowing between the cords of the carcass plies 4a and 4b during the manufacturing process, and is disposed in a region 9a between the carcass plies 4a and 4b and a region 9b between the carcass ply 4a and the carcass chafer 8.

[0023] <Tire manufacturing method> Next, a method for manufacturing a tire according to one embodiment of the present invention will be described. The method for manufacturing a tire according to this embodiment is a method for manufacturing a tire having two carcass plies in which carcass cords cross each other between layers, and is, as an example, a method for manufacturing the tire described above. Items already described about the tire will not be described again.

[0024] FIG. 2 is a diagram showing a schematic view of the first and second steps. The tire manufacturing method of this embodiment includes a first step of placing the first carcass member 200 on the tire building drum 100, and a second step of placing the second carcass member 300 and the conductive rubber member 400 on the tire building drum 100 after the first step, so that the second carcass member 300 is on the tire building drum 100 side and the conductive rubber member 400 is on the opposite side of the tire building drum 100, with the conductive rubber member 400 placed on the second carcass member 300. The first carcass member 200 and the second carcass member 300 can be the same member, and one member can be used as the other member by turning it over, which is advantageous for reducing costs. Alternatively, they can be separate members. The conductive rubber members 400 with a short width as shown in the figure can be arranged side by side in the width direction on the second carcass member 300. Furthermore, the conductive rubber members 400 can also be shortened in the extension direction (the circumferential direction of the tire to be formed), in which case they can be arranged side by side in the extension direction. The effects of the tire manufacturing method of this embodiment will be described below.

[0025] The tire manufacturing method of this embodiment is a method for manufacturing a tire having two carcass plies 4a, 4b in which carcass cords cross each other between layers, and the covering rubber of the carcass ply has a loss tangent tan δ of 0.1 or less at 60° C. Therefore, as described above, the grip performance of the tire can be improved while the rolling resistance can be reduced. On the other hand, in this embodiment, the loss tangent tan δ of the covering rubber of the carcass ply at 60° C. is 0.1 or less, and the electrical conductivity is low. In contrast, the tire manufacturing method of the present embodiment includes a first step of placing the first carcass member 200 on the tire building drum 100, and a second step of placing the second carcass member 300 and the conductive rubber member 400 on the tire building drum 100 after the first step, so that the second carcass member 300 is on the tire building drum 100 side and the conductive rubber member 400 is on the opposite side of the tire building drum 100, with the conductive rubber member 400 placed on the second carcass member 300. As a result, as shown in FIG. 1, a conductive path is established from just below the inner side of the bead core 2a in the tire radial direction to just below the inner side of the belt 5 in the tire radial direction, as shown in FIG. 1. This establishes a conductive path in the order of the gum chafer rubber 10 (in this example, the carcass chafer 8), the conductive rubber member 7, the belt covering rubber of the belt 5, and the tread 3, so that static electricity from the vehicle body can be released to the road surface. As described above, according to the tire manufacturing method of the present embodiment, it is possible to manufacture a tire in which the rolling resistance of the tire is reduced while ensuring conductive paths.

[0026] Fig. 3 is a diagram showing a second example of a tire structure. Description of the same configuration as in Fig. 1 will be omitted. 3, first, as a basic structure of the tire, the tire 1 includes a bead core 2a embedded in a pair of bead portions 2, and a first carcass ply 4a formed by a first carcass member 200 includes a first carcass body portion 4a1 that spans the pair of bead portions 2 in a toroidal shape, and a first carcass folded-up portion 4a2 that extends from the first carcass body portion 4a1 and is folded back around the bead core 2a. Similarly, a second carcass ply 4b formed by a second carcass member 300 includes a second carcass body portion 4b1 that spans the pair of bead portions 2 in a toroidal shape, and a second carcass folded-up portion 4b2 that extends from the second carcass body portion 4b1 and is folded back around the bead core 2a. The conductive rubber member 7 is composed of a portion extending in the tire width direction on the tire radially outer side of the crown portion of the carcass 4, and a portion extending from the tire width direction end of the portion to the tire radially inward. A conductive rubber member 12 (of the same type (identical) as the conductive rubber member 7 in this example) is arranged around the bead core 2a (on the inner peripheral side of the carcass 4 around the bead core 2a). In the tire radially inner region of the bead core 2a, a part of the conductive rubber member 12 seeps out by flowing between the cords of the carcass plies 4a and 4b during the manufacturing process, and is arranged in the region 9a between the carcass plies 4a and 4b and the region 9b between the carcass ply 4a and the carcass chafer 8.

[0027] A first conductive member 11a (in this example, a conductive fiber member) is disposed along the first carcass ply 4a. The first conductive member 11a is composed of a first main body portion 11a1 that spans a pair of bead portions 2 in a toroidal shape, and a first folded-back portion 11a2 that extends from the first main body portion 11a1 and is folded back around the bead core 2a. In this example, the extension length of the first carcass ply 4a and the extension length of the first conductive member 11a are approximately the same. Similarly, a second conductive member 11b (in this example, a conductive fiber member) is disposed along the second carcass ply 4b. The second conductive member 11b is composed of a second main body portion 11b1 that spans a pair of bead portions 2 in a toroidal shape, and a second folded-back portion 11b2 that extends from the second main body portion 11b1 and is folded back around the bead core 2a. In this example, the extension length of the second carcass ply 4b and the extension length of the second conductive member 11b are substantially the same. The volume resistivity of the first conductive member 11a and the second conductive member 11b is, for example, 1.0×10 8 It is possible to achieve a resistance of Ω·cm or less.

[0028] 3, the end of the first carcass folded-back portion 4a2 and the end of the first folded-back portion 11a2 are located radially outward of the inner end of the conductive rubber member 7. From the viewpoint of reducing the number of members by minimizing the extension range of the conductive rubber member 7, it is preferable that the inner end of the conductive rubber member 7 is located radially outward of the end of the second carcass folded-back portion 4b2 and the end of the second folded-back portion 11b2.

[0029] In the case of FIG. 3, in the corresponding tire manufacturing method, in a first step, a first conductive member 11a (in this example, having the same extension length as the first carcass member 200) is further arranged on the first carcass member 200 on the side opposite the tire building drum 100. Similarly, in a second step, a second conductive member 11b (in this example, having the same extension length as the second carcass member 300) is further arranged on the second carcass member 300 on the tire building drum 100 side. Note that the above arrangement in the second step can be achieved by turning over the laminate consisting of the first carcass member 200 and the first conductive member 11a in the first step.

[0030] According to the manufacturing method of a tire corresponding to the example of Figure 3, as shown in Figure 3, a conductive path is established in the order of gum chafer rubber 10 (in this example, carcass chafer 8), conductive rubber member 12, part of which has seeped into the area during the manufacturing process, first folded portion 11a2 of first conductive member 11a, conductive rubber member 7, belt covering rubber of belt 5, and tread 3, so that static electricity from the vehicle body can be released to the road surface. As described above, this manufacturing method also makes it possible to manufacture a tire in which the rolling resistance of the tire is reduced while ensuring conductive paths. According to the tire manufacturing method corresponding to the example of Figure 3, the conductive rubber member 7 does not need to be present in region R1 of Figure 3, and the carcass chafer 8 can also be eliminated if necessary, which is advantageous for reducing costs and weight of the tire by reducing the number of parts.

[0031] Fig. 4 is a diagram showing a schematic diagram of a third example of a tire structure. Below, differences from the tire structure in Fig. 1 will be explained, and repeated explanation of configurations similar to those in the tire structure in Fig. 1 will be omitted.

[0032] In the example of FIG. 4, the end of the first carcass folded portion 4a2 and the end of the first folded portion 11a2 are located on the inner side in the tire width direction than the ends of the belt layers 5a and 5b. The conductive rubber member 7 is located only on the outer side in the tire radial direction of the crown portion of the carcass 4 and extends in the tire width direction. In the illustrated example, the tire width direction end of the conductive rubber member 7 is located between the end of the belt layer 5a and the end of the belt layer 5b, but this is not limited to this case. The end of the first carcass folded portion 4a2 and the end of the first folded portion 11a2 are located on the inner side in the tire width direction than the outer end of the conductive rubber member 7 in the tire width direction.

[0033] In the case of FIG. 4, in the corresponding tire manufacturing method, in a first step, a first conductive member 11a (in this example, having the same extension length as the first carcass member 200) is further arranged on the first carcass member 200 on the side opposite the tire building drum 100. Similarly, in a second step, a second conductive member 11b (in this example, having the same extension length as the second carcass member 300) is further arranged on the second carcass member 200 on the tire building drum 100 side. Note that the above arrangement in the second step can be achieved by turning over the laminate consisting of the first carcass member 200 and the first conductive member 11a in the first step.

[0034] According to the manufacturing method of a tire corresponding to the example of Figure 4, as shown in Figure 4, a conductive path is established in the order of the gum chafer rubber 10 (in this example, the carcass chafer 8), the conductive rubber member 12, part of which has seeped into the area during the manufacturing process, the first folded portion 11a2 of the first conductive member 11a, the conductive rubber member 7, the belt covering rubber of the belt 5, and the tread 3, so that static electricity from the vehicle body can be released to the road surface. As described above, this manufacturing method also makes it possible to manufacture a tire in which the rolling resistance of the tire is reduced while ensuring conductive paths. According to the tire manufacturing method corresponding to the example of FIG. 4, the conductive rubber member 7 does not need to be present in the region R2 of FIG. 4. For example, as shown in the figure, the outer end of the conductive rubber member 7 in the tire width direction can be positioned more inward in the tire width direction than the end of the widest belt layer 4a. Also, the carcass chafer 9 can be eliminated as necessary. This is particularly advantageous for reducing costs and weight of the tire by reducing the number of components.

[0035] Here, the carcass cords of the carcass ply of the tire are preferably inclined at an angle of 80° to 88° with respect to the tire circumferential direction, because this can increase the rigidity in the tire rotational direction and improve grip performance. The conductive rubber material has a volume resistivity of 1.0×10 9 A resistance of Ω·cm or less is preferable, as this increases the electrical conductivity and allows static electricity to be more reliably released to the road surface through a conductive path.

[0036] The tire may include RF tags 91, 92 as communication devices. The RF tag includes an IC chip and an antenna. The RF tag may be, for example, sandwiched between a plurality of members of the same or different types that constitute the tire. In this way, the RF tag can be easily attached during tire production, and the productivity of tires equipped with the RF tag can be improved. In this example, the RF tag may be, for example, sandwiched between a bead filler and another member adjacent to the bead filler. The RF tag may be embedded in any of the members that constitute the tire. In this way, the load applied to the RF tag can be reduced compared to when the RF tag is sandwiched between a plurality of members that constitute the tire. This can improve the durability of the RF tag. In this example, the RF tag may be, for example, embedded in a rubber member such as a tread rubber or a side rubber. It is preferable that the RF tag is not placed at a position that is a boundary between members with different rigidity in the periphery length direction, which is a direction along the tire outer surface in a cross-sectional view in the tire width direction. In this way, the RF tag is not placed at a position where distortion is likely to concentrate due to a rigidity step. Therefore, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. In this example, it is preferable that the RF tag is not disposed at a position that is, for example, a boundary between an end of the carcass and a member adjacent to the end of the carcass (e.g., a side rubber, etc.) in a cross-sectional view in the tire width direction. The number of RF tags is not particularly limited. A tire may include only one RF tag, or may include two or more RF tags. Here, an RF tag is illustrated as an example of a communication device, but a communication device different from the RF tag may also be used.

[0037] The RF tag may be disposed, for example, in the tread portion of the tire. In this way, the RF tag is not damaged by a side cut of the tire. The RF tag may be disposed, for example, in the tread center portion in the tire width direction. The tread center portion is a position where deflection is unlikely to concentrate in the tread portion. In this way, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. In addition, it is possible to suppress the occurrence of a difference in communication with the RF tag from both outer sides of the tire in the tire width direction. In this example, the RF tag may be disposed, for example, within a range of 1 / 2 of the tread width with the tire equatorial plane as the center in the tire width direction. The RF tag may be disposed, for example, at the tread end in the tire width direction. When the position of the reader that communicates with the RF tag is predetermined, the RF tag may be disposed, for example, at the tread end on one side closer to the reader. In this example, the RF tag may be disposed, for example, within a range of 1 / 4 of the tread width with the tread end as the outer end in the tire width direction.

[0038] The RF tag may be disposed, for example, on the tire cavity side of a carcass including one or more carcass plies that spans between bead portions. In this way, the RF tag is less likely to be damaged by impacts applied from the outside of the tire, or damage such as side cuts and nail penetration. As an example, the RF tag may be disposed in close contact with the surface of the carcass on the tire cavity side. As another example, when there is another member on the tire cavity side of the carcass, the RF tag may be disposed, for example, between the carcass and another member located on the tire cavity side of the carcass. An example of another member located on the tire cavity side of the carcass is an inner liner that forms the tire inner surface. As another example, the RF tag may be attached to the tire inner surface facing the tire cavity. By configuring the RF tag to be attached to the tire inner surface, it is easy to attach the RF tag to the tire and to inspect and replace the RF tag. In other words, the attachability and maintainability of the RF tag can be improved. In addition, by attaching the RF tag to the inner surface of the tire, it is possible to prevent the RF tag from becoming the core of tire failure, compared to a configuration in which the RF tag is embedded in the tire. Furthermore, when the carcass has multiple carcass plies and there is a position where multiple carcass plies are overlapped, the RF tag may be disposed between the overlapped carcass plies.

[0039] The RF tag may be disposed, for example, in the tread portion of the tire, on the outer side in the tire radial direction of the belt including one or more belt plies. As an example, the RF tag may be disposed on the outer side in the tire radial direction of the belt and in close contact with the belt. In addition, as another example, in the case where a reinforcing belt layer is provided, the RF tag may be disposed on the outer side in the tire radial direction of the reinforcing belt layer and in close contact with the reinforcing belt layer. In addition, as another example, the RF tag may be embedded in the tread rubber on the outer side in the tire radial direction of the belt. By disposing the RF tag on the outer side in the tire radial direction of the belt in the tread portion of the tire, communication with the RF tag from the outside of the tire in the tire radial direction is unlikely to be hindered by the belt. Therefore, it is possible to improve the communication with the RF tag from the outside of the tire in the tire radial direction. In addition, the RF tag may be disposed, for example, in the tread portion of the tire, on the inner side in the tire radial direction of the belt. In this way, the outer side in the tire radial direction of the RF tag is covered by the belt, so that the RF tag is unlikely to be damaged by impact from the tread surface or nail penetration. As one example, the RF tag may be disposed in the tread portion of the tire between the belt and the carcass located radially inward of the belt. In addition, if the belt has a plurality of belt plies, the RF tag may be disposed in the tread portion of the tire between any two belt plies. In this manner, the outer side of the RF tag in the radial direction of the tire is covered by one or more belt plies, so that the RF tag is less susceptible to damage from impacts from the tread surface, nail penetration, and the like.

[0040] In the case of truck and bus tires, the RF tag may be arranged, for example, sandwiched between the cushion rubber and the tread rubber or between the cushion rubber and the side rubber. In this way, the impact on the RF tag can be mitigated by the cushion rubber. Therefore, the durability of the RF tag can be improved. The RF tag may be embedded, for example, in the cushion rubber. Furthermore, the cushion rubber may be composed of a plurality of adjacent rubber members of the same or different types. In such a case, the RF tag may be arranged, sandwiched between a plurality of rubber members constituting the cushion rubber.

[0041] The RF tag may be disposed, for example, at a sidewall or bead of the tire. The RF tag may be disposed, for example, at one sidewall or one bead that is closer to a reader that can communicate with the RF tag. In this way, the communication between the RF tag and the reader can be improved. As an example, the RF tag may be disposed between the carcass and the side rubber, or between the tread rubber and the side rubber. The RF tag may be disposed, for example, between the position where the tire is at its maximum width and the position of the tread surface in the tire radial direction. In this way, the communication with the RF tag from the outside of the tire in the tire radial direction can be improved compared to a configuration in which the RF tag is disposed on the inner side in the tire radial direction from the position where the tire is at its maximum width. The RF tag may be disposed, for example, on the inner side in the tire radial direction from the position where the tire is at its maximum width. In this way, the RF tag is disposed near the bead portion that has high rigidity. Therefore, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. As an example, the RF tag may be disposed at a position adjacent to the bead core in the tire radial direction or the tire width direction. Distortion is less likely to concentrate near the bead core. Therefore, the load applied to the RF tag can be reduced. This improves the durability of the RF tag. In particular, it is preferable that the RF tag is disposed in a position radially inward of the maximum tire width position and radially outward of the bead core of the bead portion. In this manner, the durability of the RF tag can be improved, and communication between the RF tag and a reader is less likely to be hindered by the bead core, improving the communication performance of the RF tag. In addition, when the side rubber is composed of multiple rubber members of the same or different types adjacent to each other in the tire radial direction, the RF tag may be disposed by being sandwiched between the multiple rubber members constituting the side rubber.

[0042] In the case of a passenger vehicle tire, the RF tag may be sandwiched between the bead filler and a member adjacent to the bead filler. In this way, the RF tag can be placed at a position where distortion is less likely to concentrate due to the placement of the bead filler. Therefore, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. The RF tag may be sandwiched between, for example, the bead filler and the carcass. A portion of the carcass that sandwiches the RF tag together with the bead filler may be located outside the bead filler in the tire width direction, or may be located inside the tire width direction. When a portion of the carcass that sandwiches the RF tag together with the bead filler is located outside the bead filler in the tire width direction, the load applied to the RF tag due to impact or damage from the outside of the tire in the tire width direction can be further reduced. This can further improve the durability of the RF tag. In addition, the bead filler may have a portion that is located adjacent to the side rubber. In this case, the RF tag may be disposed by being sandwiched between the bead filler and the side rubber. Furthermore, the bead filler may have a portion disposed adjacent to the rubber chafer. In this case, the RF tag may be disposed by being sandwiched between the bead filler and the rubber chafer.

[0043] In the case of truck and bus tires, the RF tag may be sandwiched between the stiffener and a member adjacent to the stiffener. In this way, the RF tag can be placed at a position where distortion is less likely to concentrate due to the placement of the stiffener. Therefore, the load applied to the RF tag can be reduced. This improves the durability of the RF tag. The RF tag may be sandwiched between the stiffener and the side rubber, for example. The RF tag may also be sandwiched between the stiffener and the carcass, for example. The part of the carcass that sandwiches the RF tag together with the stiffener may be located on the outer side in the tire width direction relative to the stiffener, or may be located on the inner side in the tire width direction. When the part of the carcass that sandwiches the RF tag together with the stiffener is located on the outer side in the tire width direction relative to the stiffener, the load applied to the RF tag due to impact or damage from the outside of the tire in the tire width direction can be further reduced. This improves the durability of the RF tag. The stiffener may have a portion disposed adjacent to the rubber chafer. In this case, the RF tag may be disposed sandwiched between the stiffener and the rubber chafer. The stiffener may have a portion adjacent to the hat rubber on the outer side in the tire width direction. In this case, the RF tag may be disposed sandwiched between the stiffener and the hat rubber. The stiffener may be composed of a plurality of rubber members having different hardnesses. In this case, the RF tag may be disposed sandwiched between a plurality of rubber members constituting the stiffener. The RF tag may be disposed sandwiched between the hat rubber and a member adjacent to the hat rubber. The RF tag may be disposed sandwiched between, for example, the hat rubber and the carcass ply. In this way, the impact on the RF tag can be mitigated by the hat rubber. Therefore, the durability of the RF tag can be improved.

[0044] The RF tag may be disposed, for example, sandwiched between the rubber chafer and the side rubber. In this way, the RF tag can be disposed at a position where distortion is less likely to be concentrated due to the placement of the rubber chafer. Therefore, the load applied to the RF tag can be reduced. This allows the durability of the RF tag to be improved. The RF tag may be disposed, for example, sandwiched between the rubber chafer and the carcass. In this way, the load applied to the RF tag due to impact or damage from the rim can be reduced. This allows the durability of the RF tag to be improved.

[0045] In the case of truck and bus tires, the RF tag may be sandwiched between the nylon chafer and another member adjacent to the nylon chafer on the outer side or inner side in the tire width direction. In this way, the position of the RF tag is less likely to fluctuate when the tire is deformed. Therefore, the load applied to the RF tag when the tire is deformed can be reduced. This can improve the durability of the RF tag. The nylon chafer may have a portion adjacent to the rubber chafer on the outer side in the tire width direction, for example. In this case, the RF tag may be sandwiched between the nylon chafer and the rubber chafer. The nylon chafer may have a portion adjacent to the side rubber on the outer side in the tire width direction, for example. In this case, the RF tag may be sandwiched between the nylon chafer and the side rubber. The nylon chafer may have a portion adjacent to the stiffener on the inner side in the tire width direction, for example. In this case, the RF tag may be sandwiched between the nylon chafer and the stiffener. Moreover, the nylon chafer may have a portion adjacent to the hat rubber, for example, on the inner side in the tire width direction. In such a case, the RF tag may be arranged by being sandwiched between the nylon chafer and the hat rubber. Furthermore, the nylon chafer may have a portion adjacent to the carcass, for example, on the inner side in the tire width direction. In such a case, the RF tag may be arranged by being sandwiched between the nylon chafer and the carcass. Furthermore, the nylon chafer may have a portion adjacent to the wire chafer, for example, on the inner side in the tire width direction. In such a case, the RF tag may be arranged by being sandwiched between the nylon chafer and the wire chafer. In this way, the RF tag may be arranged by being sandwiched between the nylon chafer and another member adjacent to the outer side or inner side of the nylon chafer in the tire width direction. In particular, by covering the outer side of the RF tag in the tire width direction with the nylon chafer, the load applied to the RF tag due to impact or damage from the outside of the tire in the tire width direction can be further reduced. Therefore, the durability of the RF tag can be further improved.

[0046] The RF tag may be sandwiched between the wire chafer and another member adjacent to the wire chafer on the inner or outer side in the tire width direction. In this way, the position of the RF tag is less likely to fluctuate when the tire is deformed. Therefore, the load applied to the RF tag when the tire is deformed can be reduced. This can improve the durability of the RF tag. The other member adjacent to the wire chafer on the inner or outer side in the tire width direction may be, for example, a rubber member such as a rubber chafer. Also, the other member adjacent to the wire chafer on the inner or outer side in the tire width direction may be, for example, a carcass.

[0047] In the case of a tire for a passenger vehicle, a belt reinforcing layer may be further provided on the radially outer side of the belt. For example, the belt reinforcing layer may be formed by winding a cord made of polyethylene terephthalate continuously in a spiral shape in the tire circumferential direction. Here, the cord may be 6.9×10 -2 The belt reinforcement layer may be formed by applying an adhesive treatment under a tension of 29.4 N / tex or more, and may have an elastic modulus of 2.5 mN / dtex·% or more when a load of 29.4 N is applied, as measured at 160°C. Furthermore, the belt reinforcement layer may be disposed so as to cover the entire belt, or may be disposed so as to cover only both ends of the belt. Furthermore, the winding density per unit width of the belt reinforcement layer may vary depending on the position in the width direction. In this way, road noise and flat spots can be reduced without reducing high-speed durability.

[0048] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is considered to be a technology that can contribute to the achievement of "No. 7_Affordable and Clean Energy for All" and "No. 13_Concrete Actions Against Climate Change." [Explanation of symbols]

[0049] 1: Tires, 2: bead portion, 2a: bead core, 3: tread portion, 4: carcass, 4a, 4b: carcass ply, 5: belt; 5a, 5b: belt layer; 6: belt reinforcing layer; 7: conductive rubber member; 7a: conductive rubber member main body; 7b: conductive rubber member folded portion; 8: Carcass Chafer, 9a, 9b: Areas where the conductive rubber member 7 or the conductive rubber member 12 has leaked out, 10: gum chafer rubber, 11a: first conductive member, 11b: second conductive member, 12: conductive rubber member, 91, 92: communication device, 100: tire building drum; 200: first carcass member; 201: carcass cord of a first carcass member; 300: second carcass member; 301: carcass cord of the second carcass member; 400: Conductive rubber material

Claims

1. 1. A method for manufacturing a tire having two carcass plies, the carcass cords crossing each other between the plies, comprising the steps of: The covering rubber of the carcass ply has a loss tangent tanδ of 0.1 or less at 60 ° C., A first step of placing a first carcass component on a tire building drum; a second step of, after the first step, arranging a conductive rubber member on a second carcass member, and then arranging the second carcass member and the conductive rubber member on the tire building drum so that the second carcass member faces the tire building drum and the conductive rubber member faces the opposite side of the tire building drum.

2. In the first step, a first conductive member is further disposed on the first carcass member on a side opposite to the tire building drum; The tire includes a bead core embedded in a pair of bead portions, a first carcass ply formed by the first carcass member includes a first carcass body portion toroidally straddling the pair of bead portions, and a first carcass folded-up portion extending from the first carcass body portion and folded-up around the bead core, the first conductive member includes a first main body portion that spans the pair of bead portions in a toroidal shape, and a first folded-back portion that extends from the first main body portion and is folded back around the bead core, The tire manufacturing method according to claim 1 , wherein an end of the first carcass folded-up portion and an end of the first folded-up portion are located radially outward of an inner end of the conductive rubber member in the tire radial direction.

3. In the first step, a first conductive member is further disposed on the first carcass member on a side opposite to the tire building drum; The tire includes a bead core embedded in a pair of bead portions, a first carcass ply formed by the first carcass member includes a first carcass body portion toroidally straddling the pair of bead portions, and a first carcass folded-up portion extending from the first carcass body portion and folded-up around the bead core, the first conductive member includes a first main body portion that spans the pair of bead portions in a toroidal shape, and a first folded-back portion that extends from the first main body portion and is folded back around the bead core, The tire manufacturing method according to claim 1 , wherein an end of the first carcass folded-up portion and an end of the first folded-up portion are located on the inner side in the tire width direction than an outer end of the conductive rubber member in the tire width direction.

4. 3. The tire manufacturing method according to claim 1, wherein the carcass cord of the carcass ply of the tire is inclined at an angle of 80° to 88° with respect to the tire circumferential direction.

5. The conductive rubber member has a volume resistivity of 1.0×10 ９ The method for producing a tire according to claim 1 or 2, wherein the compressive strength is Ω·cm or less.

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