Tire manufacturing method

Abstract

A tire manufacturing method according to the present invention is a method for manufacturing a tire comprising two carcass plies in which carcass codes intersect each other between layers. Coating rubber for the carcass plies has a loss tangent tanδ of 0.1 or less at 60°C. The method comprises: a first step of disposing a first carcass member on a tire molding drum; and a second step of, after the first step and in a state in which a conductive rubber member is disposed on a second carcass member, disposing the second carcass member and the conductive rubber member on the tire molding drum such that the second carcass member is on the tire molding drum side and the conductive rubber member is on the opposite side of the tire molding drum.

Description

Tire manufacturing method

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

[0002] BACKGROUND 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).

[0003] JP 2020-203631 A JP 2021-000892 A

[0004] Meanwhile, a tire structure in which two carcass plies are arranged so that the carcass cords cross each other has also been proposed as a tire suitable for high-speed driving on a circuit, etc. In addition, in recent years, there has been a demand for the use of 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 in the carcass ply of a carcass structure such as the one 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 that can manufacture a tire that ensures a conductive path while reducing the rolling resistance of the tire.

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

[0008] According to the present invention, it is possible to provide a tire manufacturing method that can manufacture a tire that ensures a conductive path while reducing the rolling resistance of the tire.

[0009] Fig. 1 is a diagram schematically showing a first example of a tire structure; Fig. 2 is a diagram schematically showing a first step and a second step; Fig. 3 is a diagram schematically showing a second example of a tire structure; Fig. 4 is a diagram schematically showing a third example of a tire structure; Fig. 5 is a diagram for explaining the arrangement of RFIDs; Fig. 6 is a diagram for explaining the arrangement of RFIDs;

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0011] <Tire> 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 schematically showing a first example of a tire structure. In the schematic diagram, only one half in the tire width direction, bounded by the tire equatorial plane, is shown, but the other half has a similar configuration.

[0012] As shown in FIG. 1, the tire 1 includes a pair of bead portions 2, a pair of sidewall portions (not shown) connected to the pair of bead portions 2, and a tread 3 connected between the pair of sidewall portions.

[0013] A bead core 2a is embedded in each of the pair of bead portions 2. Although not shown, a bead filler may be disposed on the radially outer side of the bead core 2a. In the illustrated example, the tread 3 is made up of a cap rubber 3a and a base rubber 3b located on the radially inner side of the cap rubber. Alternatively, the tread 3 may be a single layer.

[0014] The tire 1 further includes a carcass 4 that straddles the 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 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. By configuring the carcass cords inclined at a high angle with respect to the tire circumferential direction to cross each other between layers in this manner, rigidity in the tire rotational direction can be improved, thereby improving the tire's grip performance. 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 coating 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 toroidally spanning between a pair of bead portions 2, and a first carcass folded-up portion 4a2 extending from the first carcass body portion 4a1 and 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 toroidally spanning between the pair of bead portions 2, and a second carcass folded-up portion 4b2 extending from the second carcass body portion 4b1 and folded back around the bead core 2a. From the viewpoint of improving the rigidity of the tire sidewall portion, it is preferable that the ends of the first and second carcass folded-up portions 4a2, 4b2 are positioned radially outward of the radially outer ends of the bead fillers.

[0015] In the illustrated example, the tire 1 includes a belt 5 on the radially outer side of the crown portion of the carcass 4. The belt 5 is composed of two belt layers 5a and 5b. Each belt layer 5a and 5b is composed of a belt ply, and the belt ply is formed by covering belt cords with belt covering rubber. The belt cords are not particularly limited, but may be inclined at an angle of 20 to 40 degrees relative to the tire circumferential direction, for example. It is also preferable that the belt cords cross each other between 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, fracture resistance can be ensured, while by making the loss tangent tanδ of the belt covering rubber at 60°C 0.2 or less, rolling resistance can be reduced. The volume resistivity of the belt covering rubber is 1.0 x 10 ９ It is preferable that the resistance be 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 cords, and the width in the tire width direction of the belt layer, can be various and is not limited to this example.

[0016] In the illustrated example, the tire 1 includes a belt reinforcing layer 6, one layer in the illustrated example, on the tire radial 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 belt reinforcing layer cords with belt reinforcing layer coating rubber. The belt reinforcing layer cords are not particularly limited, but may extend, for example, in the tire circumferential direction. Furthermore, the loss tangent tanδ of the belt reinforcing layer coating rubber at 60°C is preferably 0.12 to 0.2. By making the loss tangent tanδ of the belt reinforcing layer coating rubber at 60°C 0.12 or more, fracture resistance can be ensured, while by making the loss tangent tanδ of the belt reinforcing layer coating rubber at 60°C 0.2 or less, rolling resistance can be reduced. The volume resistivity of the belt reinforcing layer coating rubber is 1.0 x 10 ９It is preferable that the elastic modulus be 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 belt reinforcing layers, the inclination angle of the belt reinforcing layer cords, and the width of the belt reinforcing layer in the tire width direction, can be various and is not limited to this example.

[0017] As shown in FIG. 1 , the tire 1 further includes a conductive rubber member 7 located radially outward of the crown portion of the carcass 4 and radially inward of the belt 5. In the illustrated example, the conductive rubber member 7 includes a conductive rubber member main body portion 7a extending from the radially outward of the crown portion of the carcass 4 and the radially inward of the belt 5, and spanning a pair of bead portions 2 in a toroidal shape, and a conductive rubber member folded-back portion 7b extending from the conductive rubber member main body portion 7a and folded back around the bead core 2a to terminate. In this example, the end of the conductive rubber member folded-back portion 7b is located radially inward of the radially outward end of the bead core 2a. This allows the extension length to be minimized, thereby reducing the tire weight, while still establishing a conductive path as described below. 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 be more reliably released to the road surface through the conductive path. On the other hand, from the viewpoint of reducing 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.

[0018] The tire 1 also includes a carcass chafer 8 around the bead core 2 a (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 2 a, a portion of the conductive rubber member 7 flows between the cords of the carcass plies 4 a and 4 b during the manufacturing process and seeps out, and is disposed in a region 9 a between the carcass plies 4 a and 4 b and a region 9 b between the carcass ply 4 a and the carcass chafer 8.

[0019] <Tire Manufacturing Method> Next, a tire manufacturing method according to one embodiment of the present invention will be described. The tire manufacturing method of this embodiment is a method for manufacturing a tire having two carcass plies in which carcass cords cross each other between layers, and is, for example, a method for manufacturing the tire described above. Items already described about the tire will not be described again.

[0020] FIG. 2 is a diagram illustrating the first and second steps. The tire manufacturing method of this embodiment includes a first step of placing a first carcass member 200 on a 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, with the conductive rubber member 400 placed on the second carcass member 300, so that the second carcass member 300 faces the tire building drum 100 and the conductive rubber member 400 faces the opposite side of the tire building drum 100. 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 upside down, which is advantageous for reducing costs. Alternatively, they can be separate members. As shown in the figure, narrow conductive rubber members 400 can be placed side by side in the width direction on the second carcass member 300. In addition, 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.

[0021] In the tire manufacturing method of this embodiment, first, a tire is manufactured 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 tanδ of 0.1 or less at 60°C. Therefore, as described above, the grip performance of the tire can be improved while also reducing rolling resistance. On the other hand, in this embodiment, the covering rubber of the carcass ply has a loss tangent tanδ of 0.1 or less at 60°C, and therefore has low electrical conductivity. In contrast, 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, after the first step, placing the conductive rubber member 400 on the second carcass member 300, and then placing the second carcass member 300 and the conductive rubber member 400 on the tire building drum 100 so that the second carcass member 300 faces the tire building drum 100 and the conductive rubber member 400 faces the opposite side of the tire building drum 100. As a result, as shown in Figure 1, a conductive path is established by the conductive rubber member 7 from just below the inner side in the tire radial direction of the bead core 2a to just below the inner side in the tire radial direction of the belt 5. As a result, 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 7, the belt covering rubber of the belt 5, and the tread 3, so that static electricity from the vehicle body can be dissipated to the road surface. As described above, according to the tire manufacturing method of the present embodiment, it is possible to manufacture a tire that ensures conductive paths while reducing the rolling resistance of the tire.

[0022] FIG. 3 is a diagram schematically illustrating a second example of a tire structure. Description of components similar to those in FIG. 1 will be omitted. In the tire 1 illustrated in FIG. 3 , the basic structure of the tire 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 toroidally spanning the pair of bead portions 2 and a first carcass folded-up portion 4a2 extending from the first carcass body portion 4a1 and 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 toroidally spanning the pair of bead portions 2 and a second carcass folded-up portion 4b2 extending from the second carcass body portion 4b1 and folded back around the bead core 2a. The conductive rubber member 7 consists 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 that portion toward the tire radially inward. Also, 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 circumferential side of the carcass 4 around the bead core 2a). Also, in the region on the tire radially inner side of the bead core 2a, a portion 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 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] 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 includes 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 substantially 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 includes 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 make it Ω·cm or less.

[0024] 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 tire radially inner end of the conductive rubber member 7. From the viewpoint of minimizing the extension range of the conductive rubber member 7 and reducing the number of members, it is preferable that the tire radially inner end of the conductive rubber member 7 be located radially outward of the end of the second carcass folded-back portion 4b2 and the end of the second folded-back portion 11b2.

[0025] In the case of Figure 3, in the corresponding tire manufacturing method, in a first step, a first conductive member 11a (in this example, having an extension length equivalent to that of 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 an extension length equivalent to that of 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 layered body made up of the first carcass member 200 and the first conductive member 11a in the first step.

[0026] According to the tire manufacturing method corresponding to the example shown in FIG. 3 , a conductive path is established in the following order: gum chafer rubber 10 (in this example, carcass chafer 8), conductive rubber member 12, a portion of which has leaked into the region 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, allowing static electricity from the vehicle body to be dissipated to the road surface. As described above, this manufacturing method also makes it possible to manufacture a tire that maintains a conductive path while reducing tire rolling resistance. According to the tire manufacturing method corresponding to the example shown in FIG. 3 , the conductive rubber member 7 does not need to be present in region R1 of FIG. 3 , and the carcass chafer 8 can be eliminated if necessary, which is advantageous for reducing costs and weight of the tire by reducing the number of components.

[0027] Fig. 4 is a diagram schematically illustrating a third example of a tire structure. Below, differences from the tire structure in Fig. 1 will be described, and a repeated description of the same configuration as the tire structure in Fig. 1 will be omitted.

[0028] 4, the ends of the first carcass folded portion 4a2 and the first folded portion 11a2 are located more inward 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 tire radially outer side 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. The ends of the first carcass folded portion 4a2 and the first folded portion 11a2 are located more inward in the tire width direction than the outer end of the conductive rubber member 7 in the tire width direction.

[0029] In the case of Figure 4, in the corresponding tire manufacturing method, in a first step, a first conductive member 11a (in this example, having an extension length equivalent to that of 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 an extension length equivalent to that of 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 layered body made up of the first carcass member 200 and the first conductive member 11a in the first step.

[0030] According to the tire manufacturing method corresponding to the example shown in FIG. 4 , a conductive path is established in the following order: gum chafer rubber 10 (in this example, carcass chafer 8), conductive rubber member 12, a portion of which has leaked into the region 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, allowing static electricity from the vehicle body to be dissipated to the road surface. As described above, this manufacturing method also makes it possible to manufacture a tire that ensures a conductive path while reducing tire rolling resistance. According to the tire manufacturing method corresponding to the example shown in FIG. 4 , the conductive rubber member 7 does not need to be present in region R2 of FIG. 4 . For example, as shown, 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. Furthermore, the carcass chafer 9 can be eliminated if necessary. This is particularly advantageous for reducing costs and weight of the tire by reducing the number of components.

[0031] Here, it is preferable that the carcass cords of the carcass ply of the tire are inclined at an angle of 80° to 88° with respect to the tire circumferential direction. This is because it is possible to increase the rigidity in the tire rotation direction and improve grip performance. In addition, the conductive rubber member has a volume resistivity of 1.0×10 ９ It is preferable that the resistance is Ω·cm or less, because this increases the conductivity and allows static electricity to be more reliably released to the road surface through a conductive path.

[0032] 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 multiple components of the same or different types that make up the tire. This makes it easier to attach the RF tag during tire production, improving the productivity of tires equipped with RF tags. In this example, the RF tag may be sandwiched between a bead filler and another component adjacent to the bead filler. The RF tag may also be embedded in any of the components that make up the tire. This reduces the load on the RF tag compared to when the RF tag is sandwiched between multiple components that make up the tire. This improves the durability of the RF tag. In this example, the RF tag may be embedded in a rubber component such as tread rubber or side rubber. It is preferable that the RF tag is not placed at a position that is a boundary between components with different rigidities in the periphery length direction, which is the direction along the outer surface of the tire in a cross-sectional view in the tire width direction. By doing so, the RF tag is not placed in a position where distortion is likely to concentrate due to a difference in rigidity. 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 placed in a position that is, for example, the boundary between the end of the carcass and a member adjacent to the end of the carcass (for example, 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 be equipped with only one RF tag, or may be equipped with two or more RF tags. Here, an RF tag is described as an example of a communication device, but a communication device other than an RF tag may also be used.

[0033] The RF tag may be disposed, for example, in the tread portion of the tire. In this manner, the RF tag will not be 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 in the tread portion where flexure is less likely to concentrate. In this manner, the load applied to the RF tag can be reduced. This improves the durability of the RF tag. Also, it is possible to prevent differences 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 centered on the tire equatorial plane in the tire width direction. The RF tag may be disposed, for example, at the tread edge in the tire width direction. If the position of a reader that communicates with the RF tag is predetermined, the RF tag may be disposed, for example, at the tread edge 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 in the tire width direction, with the tread edge as the outer end.

[0034] The RF tag may be positioned, for example, closer to the tire cavity than a carcass including one or more carcass plies spanning between bead portions. This configuration makes the RF tag less susceptible to damage from impacts applied from outside the tire or damage such as side cuts or nail penetration. As an example, the RF tag may be positioned in close contact with the surface of the carcass facing the tire cavity. As another example, if there is another component closer to the tire cavity than the carcass, the RF tag may be positioned, for example, between the carcass and another component located closer to the tire cavity than the carcass. An example of another component located closer to the tire cavity than 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. Configuring the RF tag to be attached to the tire inner surface makes it easier to attach the RF tag to the tire and to inspect and replace the RF tag. In other words, the ease of attaching and maintaining the RF tag can be improved. Furthermore, by attaching the RF tag to the inner surface of the tire, it is possible to prevent the RF tag from becoming a nucleus 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.

[0035] The RF tag may be arranged, for example, in the tread portion of the tire, radially outward of a belt including one or more belt plies. As one example, the RF tag may be arranged radially outward of the belt in the tire radial direction and in close contact with the belt. As another example, if a reinforcing belt layer is provided, the RF tag may be arranged radially outward of the reinforcing belt layer in close contact with the reinforcing belt layer. As another example, the RF tag may be embedded in the tread rubber radially outward of the belt. By arranging the RF tag radially outward 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 less likely to be obstructed by the belt. Therefore, communication with the RF tag from the outside of the tire in the tire radial direction can be improved. As another example, the RF tag may be arranged radially inward of the belt in the tread portion of the tire. In this way, the outer side of the RF tag in the tire radial direction is covered by the belt, making the RF tag less susceptible to damage from impacts 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. Furthermore, if the belt has multiple 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 tire radial direction is covered by one or more belt plies, making the RF tag less susceptible to damage from impacts from the tread surface, nail penetration, and the like.

[0036] In the case of truck and bus tires, the RF tag may be sandwiched between the cushion rubber and the tread rubber or between the cushion rubber and the side rubber, for example. In this way, the cushion rubber can absorb impacts on the RF tag. This improves the durability of the RF tag. The RF tag may also be embedded in the cushion rubber, for example. Furthermore, the cushion rubber may be made up of multiple adjacent rubber members of the same or different types. In such cases, the RF tag may be sandwiched between the multiple rubber members that make up the cushion rubber.

[0037] The RF tag may be disposed, for example, in a sidewall portion or a bead portion of the tire. The RF tag may be disposed, for example, in one sidewall portion or one bead portion that is closer to a reader capable of communicating with the RF tag. This improves communication between the RF tag and the reader. 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 tire's maximum width position and the tread surface position in the tire radial direction. This improves communication with the RF tag from the tire's outer side in the tire radial direction compared to a configuration in which the RF tag is disposed radially inward of the tire's maximum width position. The RF tag may be disposed, for example, radially inward of the tire's maximum width position. This allows the RF tag to be disposed near the bead portion, which has high rigidity. This reduces the load applied to the RF tag. This improves durability of the RF tag. As an example, the RF tag may be disposed 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. This reduces the load on the RF tag, improving the durability of the RF tag. In particular, it is preferable that the RF tag be positioned radially inward of the tire's maximum width position and radially outward of the bead core of the bead portion. This improves the durability of the RF tag, and communication between the RF tag and a reader is less likely to be obstructed by the bead core, improving the communication performance of the RF tag. Furthermore, when the side rubber is composed of multiple rubber members of the same or different types adjacent in the tire radial direction, the RF tag may be sandwiched between the multiple rubber members that make up the side rubber.

[0038] In the case of a passenger vehicle tire, the RF tag may be sandwiched between a bead filler and a member adjacent to the bead filler. This allows the RF tag to be placed in a position where strain is less likely to concentrate due to the placement of the bead filler. Therefore, the load on the RF tag can be reduced. This improves the durability of the RF tag. The RF tag may be sandwiched between, for example, the bead filler and the carcass. The portion of the carcass that sandwiches the RF tag together with the bead filler may be located on the outer side of the bead filler in the tire width direction, or on the inner side of the bead filler in the tire width direction. When the portion of the carcass that sandwiches the RF tag together with the bead filler is located on the outer side of the bead filler in the tire width direction, the load on 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 bead filler may also 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.

[0039] In the case of truck and bus tires, the RF tag may be disposed sandwiched between a stiffener and a member adjacent to the stiffener. This allows the RF tag to be disposed in a position where strain is less likely to concentrate due to the stiffener. Therefore, the load on the RF tag can be reduced. This improves the durability of the RF tag. The RF tag may be disposed sandwiched between the stiffener and a side rubber, for example. The RF tag may also be disposed sandwiched between the stiffener and a carcass, for example. The portion of the carcass that sandwiches the RF tag together with the stiffener may be located on the outer side of the stiffener in the tire width direction, or on the inner side of the tire width direction. When the portion of the carcass that sandwiches the RF tag together with the stiffener is located on the outer side of the stiffener in the tire width direction, the load on 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 such a 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 such a 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 such a case, the RF tag may be disposed sandwiched between the 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, for example, between the hat rubber and the carcass ply. In this way, impacts on the RF tag can be mitigated by the hat rubber. This can improve the durability of the RF tag.

[0040] The RF tag may be arranged, for example, sandwiched between the rubber chafer and the side rubber. In this way, the RF tag can be arranged in a position where the placement of the rubber chafer makes it less likely for distortion to concentrate. This reduces the load on the RF tag. This improves the durability of the RF tag. The RF tag may be arranged, for example, sandwiched between the rubber chafer and the carcass. In this way, it reduces the load on the RF tag due to impacts or damage from the rim. This improves the durability of the RF tag.

[0041] In the case of truck and bus tires, the RF tag may be sandwiched between a nylon chafer and another member adjacent to the nylon chafer on the outer or inner side in the tire width direction. This makes it difficult for the position of the RF tag to fluctuate when the tire deforms. Therefore, the load applied to the RF tag when the tire deforms can be reduced. This improves the durability of the RF tag. The nylon chafer may, for example, have a portion adjacent to the rubber chafer on the outer side in the tire width direction. In such a case, the RF tag may be sandwiched between the nylon chafer and the rubber chafer. The nylon chafer may, for example, have a portion adjacent to the side rubber on the outer side in the tire width direction. In such a case, the RF tag may be sandwiched between the nylon chafer and the side rubber. The nylon chafer may, for example, have a portion adjacent to the stiffener on the inner side in the tire width direction. In such a case, the RF tag may be sandwiched between the nylon chafer and the side rubber. Furthermore, 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 disposed 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 disposed 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 disposed by being sandwiched between the nylon chafer and the wire chafer. In this way, the RF tag may be disposed by being sandwiched between the nylon chafer and another member adjacent to the nylon chafer on the outer or inner side 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.

[0042] The RF tag may be sandwiched between the wire chafer and another adjacent member on the inner or outer side of the wire chafer in the tire width direction. This makes it difficult for the position of the RF tag to fluctuate when the tire deforms. Therefore, the load applied to the RF tag when the tire deforms can be reduced. This improves the durability of the RF tag. The other adjacent member on the inner or outer side of the wire chafer in the tire width direction may be, for example, a rubber member such as a rubber chafer. Furthermore, the other adjacent member on the inner or outer side of the wire chafer in the tire width direction may be, for example, a carcass.

[0043] 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 and spirally in the tire circumferential direction. Here, the cord may be 6.9 x 10 －２ The belt reinforcement layer may be formed by applying an adhesive treatment under a tension of 1000 N / tex or more, and have an elastic modulus of 2.5 mN / dtex% or more when measured at 160°C under a load of 29.4 N. Furthermore, the belt reinforcement layer may be disposed so as to cover the entire belt or 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. By doing so, road noise and flat spots can be reduced without reducing high-speed durability.

[0044] [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 thought to be a technology that can contribute to goals such as "No. 7: Affordable and Clean Energy" and "No. 13: Climate Action."

[0045] LIST OF NUMERALS 1: Tire, 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 portion, 7b: Conductive rubber member folded portion, 8: Carcass chafer, 9a, 9b: Area where conductive rubber member 7 or conductive rubber member 12 has seeped 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 first carcass member, 300: Second carcass member, 301: Carcass cord of second carcass member 400: Conductive rubber member

Claims

1. A method for manufacturing a tire having two carcass plies in which carcass cords cross each other between layers, the covering rubber of the carcass ply having a loss tangent tan δ of 0.1 or less at 60°C, comprising: a first step of arranging a first carcass member on a tire building drum; and a second step of arranging, after the first step, a conductive rubber member on the 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 is on the opposite side of the tire building drum.

2. A method for manufacturing a tire as described in claim 1, wherein 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 has a bead core embedded in a pair of bead portions, the first carcass ply formed by the first carcass member comprises a first carcass main body portion toroidally spanning between the pair of bead portions and a first carcass fold-back portion extending from the first carcass main body portion and folded back around the bead core, the first conductive member comprises a first main body portion toroidally spanning between the pair of bead portions and a first fold-back portion extending from the first main body portion and folded back around the bead core, and an end of the first carcass fold-back portion and an end of the first fold-back portion are located radially outward of the radially inner end of the conductive rubber member.

3. A method for manufacturing a tire as described in claim 1, wherein 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 has a bead core embedded in a pair of bead portions, the first carcass ply formed by the first carcass member comprises a first carcass main body portion toroidally spanning between the pair of bead portions and a first carcass fold-back portion extending from the first carcass main body portion and folded back around the bead core, the first conductive member comprises a first main body portion toroidally spanning between the pair of bead portions and a first fold-back portion extending from the first main body portion and folded back around the bead core, and an end of the first carcass fold-back portion and an end of the first fold-back portion are located on the inner side in the tire width direction than the outer end of the conductive rubber member in the tire width direction.

4. A method for manufacturing a tire according to any one of claims 1 to 3, wherein the carcass cords of the carcass ply of the tire are inclined at an angle of 80° to 88° with respect to the circumferential direction of the tire.

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 claims 1 to 4, wherein the compressive strength is Ω·cm or less.

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