tire

Abstract

To provide a tire having a structure facilitating the release of static electricity from a vehicle to a road surface.SOLUTION: A tire includes a plurality of conductive members. The conductive members extend from a rubber chafer to a reinforcement layer. An outer end in the tire radial direction of at least one conductive member is positioned in a region sandwiched by a perpendicular drawn down in a normal direction of a ground plane from each of both ends in the tire circumferential direction of the ground plane. (Alternatively, an interval between the outer ends in the tire circumferential direction of the conductive members adjacent in the tire circumferential direction is L2 (mm) or less, or the number of the plurality of conductive members is L1 / L2 or more.)SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, there have been proposed tires having a structure that allows static electricity transmitted from a vehicle to a bead portion to escape from the tread surface to the road surface (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-203631 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described tires, there is a demand for more reliable dissipation of static electricity to the road surface. Meanwhile, there is a demand for reduced rolling resistance in tires, and in order to reduce the loss tangent of the coating rubber of the tire components, for example, the amount of carbon in the coating rubber may be reduced. However, reducing the amount of carbon increases the electrical resistance of the coating rubber, which may result in the conductive path from the bead portion to the tread surface being blocked by the coating rubber of the tire components. In particular, in such cases, there is a demand for more reliable dissipation of static electricity to the road surface.

[0005] Therefore, an object of the present invention is to provide a tire having a structure that allows static electricity from a vehicle to easily dissipate to the road surface. [Means for solving the problem]

[0006] The gist and configuration of the present invention are as follows. (1) a pair of bead portions; a carcass consisting of one or more carcass plies toroidally spanning the pair of bead portions; a reinforcing member consisting of one or more reinforcing layers provided on the tire radial direction outer side of the crown portion of the carcass; A tire comprising: a rubber chafer arranged on an outer surface side of the bead portion in the tire width direction, The tire further includes a plurality of conductive members, The conductive member extends from the rubber chafer to the reinforcing layer, A tire characterized in that, when the tire is mounted on an applicable rim, inflated to a specified internal pressure, and subjected to a maximum load, in a side view of the tire, the radially outer ends of one or more of the conductive members are located within an area sandwiched between perpendicular lines drawn from both ends of the tire circumferential direction of the contact patch in a direction normal to the contact patch.

[0007] In this specification, "applicable rim" refers to the standard rim (Measuring Rim in the ETRTO Standards Manual, Design Rim in the TRA Year Book) for the applicable size that is described or will be described in the future, as an industrial standard in effect in the region where the tire is produced and used, such as the JATMA Year Book of the Japan Automobile Tire Manufacturers Association (JATMA) in Japan, the Standards Manual of the European Tyre and Rim Technical Organization (ETRTO) in Europe, or the Year Book of the Tire and Rim Association, Inc. (TRA) in the United States (in other words, the above "rim" includes not only current sizes but also sizes that may be included in the above industrial standards in the future. An example of a "size to be described in the future" is the size listed under "FUTURE DEVELOPMENTS" in the 2013 edition of the ETRTO.), however, in the case of a size not described in the above industrial standards, it refers to a rim with a width that corresponds to the bead width of the tire. Furthermore, "specified internal pressure" refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity of a single wheel for the applicable size and ply rating as specified in the above JATMA etc., and in the case of sizes not specified in the above industry standards, "specified internal pressure" refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity specified for each vehicle on which the tire is fitted. The "ground contact surface" refers to the surface that is in contact with the road surface in the above-mentioned state.

[0008] (2) a pair of bead portions; a carcass consisting of one or more carcass plies toroidally spanning the pair of bead portions; a reinforcing member consisting of one or more reinforcing layers provided on the tire radial direction outer side of the crown portion of the carcass; A tire comprising: a rubber chafer arranged on an outer surface side of the bead portion in the tire width direction, The tire further includes a plurality of conductive members, The conductive member extends from the rubber chafer to the reinforcing layer, When the contact length of the tire is L2 (mm), In a side view of the tire, the distance between radially outer ends of the conductive members adjacent in the tire circumferential direction is L2 (mm) or less. Here, the term "contact length" refers to the maximum length of the contact patch in the tire circumferential direction. In addition, "spacing" refers to the length of an arc centered on the tire axis and having the tire radially outer ends of the conductive members adjacent in the tire circumferential direction as endpoints, in the tire side view.

[0009] (3) a pair of bead portions; a carcass consisting of one or more carcass plies toroidally spanning the pair of bead portions; a reinforcing member consisting of one or more reinforcing layers provided on the tire radial direction outer side of the crown portion of the carcass; A tire comprising: a rubber chafer arranged on an outer surface side of the bead portion in the tire width direction, The tire further includes a plurality of conductive members, The conductive member extends from the rubber chafer to the reinforcing layer, the plurality of conductive members are arranged at equal intervals in the tire circumferential direction, A tire characterized in that, when the outer circumferential length of the tire is L1 and the ground contact length of the tire is L2, the number of the plurality of conductive members is equal to or greater than L1 / L2.

[0010] (4) The tire according to any one of (1) to (3) above, wherein the conductive member extends linearly in a side view of the tire.

[0011] (5) The tire according to any one of (1) to (4) above, wherein the plurality of conductive members extend radially from the center of the tire in a side view of the tire.

[0012] (6) The tire according to any one of (1) to (3) above, wherein the conductive member extends in a curved shape in a side view of the tire.

[0013] (7) The tire according to any one of (1) to (6) above, wherein, in a side view of the tire, the distance between the plurality of conductive members is greater than the width of the conductive members. The "distance" mentioned above refers to the shortest distance when viewed from the side of the tire.

[0014] (8) The tire according to any one of (1) to (7) above, wherein the conductive member is a conductive fiber member.

[0015] (9) The tire according to (8) above, wherein the conductive fiber member is a mixture of cotton fiber and SUS fragments twisted together. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a tire having a structure that allows static electricity from a vehicle to easily dissipate to the road surface. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of a tire structure of a tire according to one embodiment of the present invention. [Figure 2] 1 is a side view of a tire according to one embodiment of the present invention. [Figure 3] FIG. [Figure 4] FIG. 2 is a schematic diagram for explaining the configuration of the present embodiment. [Figure 5] FIG. 10 is a side view of another modified example. [Figure 6] FIG. 10 is a side view of yet another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] (First embodiment) Fig. 1 is a schematic diagram of the tire structure of a tire according to one embodiment of the present invention. In this example, the tire 1 is a pneumatic tire. As shown in Fig. 1, the tire 1 includes a pair of bead portions 2, a carcass 3, a reinforcing member disposed radially outward of the carcass 3, and a tread 5.

[0020] In this example, a pair of bead cores 2a are embedded in the pair of bead portions 2, and bead fillers 2b are arranged on the tire radial outer sides of the bead cores 2a. The cross-sectional shape and material of the bead cores 2a are not particularly limited, and may be any structure commonly used in tires. The bead fillers 2b may have a substantially triangular cross section, but the cross-sectional shape of the bead fillers 2b is not limited to this example, and the material is not particularly limited either.

[0021] The carcass 3 is made up of one or more carcass plies, each of which includes a carcass body 3a that straddles a pair of bead cores in a toroidal shape and a carcass folded-up portion 3b that extends from the carcass body 3a and folds back around the bead cores 2a. In this embodiment, the carcass ply is made of organic fibers coated with rubber, and the coated rubber has a small loss tangent. This reduces the rolling resistance of the tire. Here, "loss tangent" refers to the ratio (E" / E') of the dynamic loss modulus E" to the dynamic storage modulus E', obtained using a dynamic tensile viscoelasticity measuring tester on a vulcanized rubber test piece having a thickness of 2 mm, a width of 5 mm, and a length of 20 mm, under conditions of a temperature of 60°C, a frequency of 52 Hz, an initial strain of 2%, and a dynamic strain of 1%. In this embodiment, the carcass ply is non-conductive (it does not function sufficiently as a conductive path to release static electricity inside the tire to the road surface).

[0022] Additionally, a rubber chafer (gum chafer) 6 is disposed on the outer surface side of the bead portion 2 in the tire width direction (in this example, on the outer side of the bead filler 2b in the tire width direction). The rubber chafer 6 covers the carcass folded-up portion 3b from the outer side in the tire width direction. The rubber chafer 6 is electrically conductive. The rubber chafer 6 is disposed in at least a part of the contact portion of the bead portion 2 with the rim.

[0023] In this example, a canvas chafer 7 is disposed around the bead core 2a. The canvas chafer 7 covers the inner side of the bead core 2a in the tire radial direction and both sides in the tire width direction. The canvas chafer 7 is electrically conductive. The canvas chafer 7 is made of a woven fabric and rubber impregnated into the woven fabric. The woven fabric is made of warp and weft threads, and the warp and weft threads are made of organic fibers.

[0024] As shown in Fig. 1, a squeegee rubber 8 is disposed on the radially inner side of the bead core 2a (in the illustrated example, on the radially inner side of the carcass folded-up portion 3b and on the radially inner side of the canvas chafer 7). This prevents contact between the carcass ply and the canvas chafer 7, thereby suppressing breakdowns due to friction. The squeegee rubber 8 is non-conductive.

[0025] Here, a reinforcing member consisting of one or more reinforcing layers is arranged on the tire radially outer side of the crown portion of the carcass 3. In the illustrated example, the reinforcing member includes a belt 4 consisting of two belt layers 4a and 4b, one belt reinforcing layer 9 arranged on the tire radially outer side of the belt 4, and a reinforcing rubber (tread undercushion) 10 arranged on the tire radially outer side of the belt reinforcing layer 9.

[0026] The belt layers 4a, 4b are made of plies of rubber-coated belt cords inclined (for example, at an inclination angle of 30 to 60 degrees) with respect to the tire circumferential direction so that they intersect with each other between the layers. The belt cords may be, for example, steel cords. Thus, the belt layers 4a, 4b are electrically conductive. Note that in this example, there are two belt layers, but one or more layers may be used, and the inclination angle with respect to the tire circumferential direction is not limited to the above range.

[0027] The belt reinforcing layer 9 is made of a ply of rubber-coated cords extending in the tire circumferential direction. In this example, the belt layer 9 is a pair of layer layers that cover only the tire width direction ends of the belt 4. The cords can be, for example, steel cords. The belt reinforcing layer 9 is non-conductive. When the belt reinforcing layer 9 is a layer layer, the belt layer is not disposed except at positions corresponding to the belt ends, so that the tire width direction region between the pair of layer layers forms a conductive path. Note that in this example, the belt reinforcing layer 9 is a single layer layer, but it can also be made of two or more layers. For example, a so-called cap layer that covers the entire belt width can be further disposed between the belt 4 and the layer layer in the tire radial direction. Alternatively, only a cap layer can be disposed. In the case of a cap layer, it is conductive. Each reinforcing layer is either conductive to form a conductive path, or non-conductive but is disposed only in a portion in the tire width direction, so that the area where the reinforcing layer is not disposed becomes a conductive path. Note that in this embodiment, the tire 1 does not necessarily have to have the belt reinforcing layer 9. The belt reinforcing layer 9 can also be disposed on the inner side of the belt 4 in the tire radial direction.

[0028] In the illustrated example, the reinforcing rubber (tread undercushion) 10 is disposed between the tread 5 and the belt reinforcing layer 9 in the tire radial direction. The tread undercushion 10 is electrically conductive. The tread is not electrically conductive. The tread 5 can have, for example, a so-called cap-and-base structure, in which a cap rubber is disposed on the radially outer side of the base rubber. A portion of the tread 5 in the tire width direction serves as an antenna rubber 5a. The antenna rubber 5a is electrically conductive. The antenna rubber 5a can be disposed continuously in the tire circumferential direction, or can be disposed intermittently.

[0029] Here, the tire 1 of this embodiment further includes a plurality of conductive members 11. In this example, the conductive members 11 are conductive fiber members. The conductive fiber members can be, for example, a mixture of cotton fiber and SUS fragments twisted together. This allows for a lightweight and conductive fiber. For weight reduction, it is preferable that the fiber be made of only one strand.

[0030] In this embodiment, the conductive member 11 extends from the rubber chafer 6 to the reinforcing layer. In this example, the tire radially inner end of the conductive member 11 is located at the tire radially outer end of the rubber chafer 6 or, as shown in the figure, in a tire radial direction region that is radially inward of the tire radially outer end of the rubber chafer 6. This allows electrical contact between the rubber chafer 6 and the tire radially inner end of the conductive member 11. Furthermore, the conductive member 11 extends from the tire radially inner end to the tire radially outer side, at least to the position of any one of the one or more reinforcing layers that has conductivity. In the first embodiment shown in FIG. 1 , the tire 1 has a pair of conductive members 11, one for each half of the tire width direction, with the tire equatorial plane as the boundary. Therefore, each conductive member 11 has a tire radially outer end. The tire radially outer end of the conductive member 11 terminates at the end of any one of the one or more reinforcing layers that has conductivity (in the illustrated example, the belt layer 4a). That is, the outer end in the tire radial direction of the conductive member 11 terminates in a region in the tire radial direction between the crown portion of the carcass 3 and the innermost conductive reinforcing layer in the tire radial direction (in the illustrated example, the belt layer 4a) among the one or more reinforcing layers, thereby electrically connecting the outer end in the tire radial direction of the conductive member 11 and the belt 4a. In this way, a conductive path through which static electricity can escape is formed in the following order: rubber chafer 6, conductive member 11, belt layer 4a, belt layer 4b, the tire width direction region between a pair of belt reinforcing layers 9, tread undercushion 10, and antenna rubber 5a.

[0031] The tire radially outer end of the conductive member 11 may terminate in a tire radial direction region between the tread 5 and the one or more reinforcing layers that are conductive and located outermost in the tire radial direction (the tread undercushion 10 in the illustrated example). In this case, a conductive path through which static electricity can escape can be formed in the order of the rubber chafer 6, the conductive member 11, the tread undercushion 10, and the antenna rubber 5a.

[0032] 2 is a side view of a tire according to one embodiment of the present invention. In the tire of this embodiment, when the tire is mounted on an applicable rim, inflated to a specified internal pressure, and subjected to a maximum load, radially outer ends of one or more conductive members 11 are located within a region sandwiched between perpendicular lines (shown by dotted lines in FIG. 2) extending from both circumferential ends of the tire to the normal direction of the contact patch. The effects of the tire of this embodiment will be described below.

[0033] According to the tire of this embodiment, at any time during rotation of the tire, the tire radial outer ends of one or more conductive members 11 are positioned in the above-mentioned region on the ground contact surface, so that a conductive path through which static electricity can escape is always formed in the order of the rubber chafer 6, conductive member 11, belt layer 4a, belt layer 4b, the tire width direction region between the pair of belt reinforcing layers 9, tread undercushion 10, and antenna rubber 5a. Therefore, according to the tire of this embodiment, static electricity from the vehicle can be easily released to the road surface. In particular, in the case of the conductive path described above, even if the carcass covering rubber is low-loss rubber (which reduces conductivity), the escape of static electricity is not hindered.

[0034] Alternatively, the tire may have multiple conductive members 11, and when the contact length of the tire 1 is L2 (mm), the distance between the radially outer ends of adjacent conductive members 11 in the tire circumferential direction may be L2 (mm) or less. In this case, as shown schematically in Figure 4, at any timing of the contact surface during tire rotation, a conductive path through which static electricity can escape is always formed in the order of the rubber chafer 6, the conductive member 11, the belt layer 4a, the belt layer 4b, the tire width direction region between the pair of belt reinforcing layers 9, the tread undercushion 10, and the antenna rubber 5a, as described above, and the same effect can be obtained.

[0035] Alternatively, the plurality of conductive members 11 may be arranged at equal intervals in the tire circumferential direction, and the number of the plurality of conductive members 11 may be set to be equal to or greater than L1 / L2, where L1 (mm) is the tire circumferential length. In this case as well, at any timing on the ground contact surface during tire rotation, a conductive path through which static electricity can escape is always formed in the order of the rubber chafer 6, conductive member 11, belt layer 4a, belt layer 4b, the region in the tire width direction between the pair of belt reinforcing layers 9, tread undercushion 10, and antenna rubber 5a, as described above, thereby achieving the same advantageous effects.

[0036] Note that, because shorter conductive paths allow electricity to escape more easily, the conductive members 11 preferably extend linearly in a side view of the tire 1, as shown in Fig. 2 and Fig. 3, for example. In particular, as shown in Fig. 2, it is preferable that the multiple conductive members 11 extend radially from the center of the tire 1 in a side view of the tire 1, which makes it easier for electricity to escape while maintaining equal intervals between the multiple conductive members 11. On the other hand, as shown in Fig. 5 and Fig. 6, the conductive members 11 may extend in a curved shape in a side view of the tire 1.

[0037] In addition, in a side view of the tire, the distance between the plurality of conductive members 11 is preferably greater than the width of the conductive members 11 (for example, the diameter of the fiber in the case of conductive fiber members). This is because by not arranging the conductive members 11 too densely, it is possible to suppress an increase in weight and an increase in rolling resistance. [Explanation of symbols]

[0038] 1: tire, 2: bead portion, 3: carcass, 4: belt, 5: Tread, 6: Rubber chafer, 7: Canvas chafer, 8: squeegee rubber, 9: belt reinforcing layer, 10: tread undercushion, 11: Conductive member,

Claims

1. a pair of bead portions; a carcass including one or more carcass plies toroidally straddling the pair of bead portions; a reinforcing member including one or more reinforcing layers provided on the tire radial direction outer side of the crown portion of the carcass; A tire comprising: a rubber chafer arranged on an outer surface side of the bead portion in the tire width direction, The carcass includes a carcass main body portion toroidally straddling a pair of bead cores, and a carcass folded-up portion folded back and extending from the carcass main body portion around the bead cores, The tire further includes a plurality of conductive members, The conductive member extends from the rubber chafer to the reinforcing layer, when the tire is mounted on an applicable rim, inflated to a specified internal pressure, and subjected to a maximum load, in a side view of the tire, outer ends of one or more of the conductive members in the tire radial direction are located within an area sandwiched between perpendicular lines drawn from both ends of the tire circumferential direction of the ground contact surface in a normal direction to the ground contact surface, The tire further comprises a conductive canvas chafer around the bead core, the conductive canvas chafer covering the radially inner side of the bead core and both sides in the tire width direction, and the radially inner end of the conductive member is positioned in the tire width direction in the following order from the outer side in the tire width direction: the rubber chafer, the conductive member, the canvas chafer, the carcass folded portion, and the bead filler.

2. a pair of bead portions; a carcass including one or more carcass plies toroidally straddling the pair of bead portions; a reinforcing member including one or more reinforcing layers provided on the tire radial direction outer side of the crown portion of the carcass; A tire comprising: a rubber chafer arranged on an outer surface side of the bead portion in the tire width direction, The carcass includes a carcass main body portion toroidally straddling a pair of bead cores, and a carcass folded-up portion folded back and extending from the carcass main body portion around the bead cores, The tire further includes a plurality of conductive members, The conductive member extends from the rubber chafer to the reinforcing layer, When the contact length of the tire is L2 (mm), In a side view of the tire, a distance between tire radial direction outer ends of the conductive members adjacent to each other in the tire circumferential direction is L2 (mm) or less, The tire further comprises a conductive canvas chafer around the bead core, the conductive canvas chafer covering the radially inner side of the bead core and both sides in the tire width direction, and the radially inner end of the conductive member is positioned in the tire width direction in the following order from the outer side in the tire width direction: the rubber chafer, the conductive member, the canvas chafer, the carcass folded portion, and the bead filler.

3. a pair of bead portions; a carcass including one or more carcass plies toroidally straddling the pair of bead portions; a reinforcing member including one or more reinforcing layers provided on the tire radial direction outer side of the crown portion of the carcass; A tire comprising: a rubber chafer arranged on an outer surface side of the bead portion in the tire width direction, The carcass includes a carcass main body portion toroidally straddling a pair of bead cores, and a carcass folded-up portion folded back and extending from the carcass main body portion around the bead cores, The tire further includes a plurality of conductive members, The conductive member extends from the rubber chafer to the reinforcing layer, the plurality of conductive members are arranged at equal intervals in the tire circumferential direction, where L1 is a circumferential length of the tire and L2 is a ground contact length of the tire, the number of the plurality of conductive members is equal to or greater than L1 / L2, The tire further comprises a conductive canvas chafer around the bead core, the conductive canvas chafer covering the radially inner side of the bead core and both sides in the tire width direction, and the radially inner end of the conductive member is positioned in the tire width direction in the following order from the outer side in the tire width direction: the rubber chafer, the conductive member, the canvas chafer, the carcass folded portion, and the bead filler.

4. The tire according to any one of claims 1 to 3, wherein the conductive member extends linearly in a side view of the tire.

5. The tire according to any one of claims 1 to 4, wherein the plurality of conductive members extend radially from a center of the tire in a side view of the tire.

6. The tire according to any one of claims 1 to 3, wherein the conductive member extends in a curved shape in a side view of the tire.

7. The tire according to any one of claims 1 to 6, wherein, in a side view of the tire, a distance between the plurality of conductive members is greater than a width of the conductive members.

8. The tire according to any one of claims 1 to 7, wherein the conductive member is a conductive fiber member.

9. The tire according to claim 8, wherein the conductive fiber member is a mixture of cotton fiber and SUS fragments twisted together.

10. The tire according to any one of claims 1 to 9, wherein an inner end in the tire radial direction of the conductive member is located radially outward of an outer end in the tire radial direction of the bead core.

11. the carcass is non-conductive; The tire according to any one of claims 1 to 10, wherein the rubber chafer and an inner end in the tire radial direction of the conductive member are in electrical contact with each other.

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