Tire manufacturing method

Abstract

To provide a manufacturing method of a tire capable of suppressing dropout of electrically conductive threads from an outer face of a rubber material in a manufacturing process.SOLUTION: A manufacturing method of a tire 1 includes a first step of bonding electrically conductive threads 10 which reduce electric resistance of the tire 1 to an outer face 16 of an unvulcanized rubber material 15 constituting the tire 1. The first step includes, before arranging the electrically conductive threads 10, and / or, simultaneously with arranging the electrically conductive threads 10 to the outer face 16 of the rubber material 15, a step of heating the outer face 16 of the rubber material 15.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Generally, when the electrical resistance of a tire increases, static electricity may accumulate in the vehicle, causing radio interference such as radio noise. To prevent such problems, for example, Patent Document 1 below proposes a pneumatic tire in which conductive yarns are arranged on the outer surface of the carcass ply. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6544140 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the pneumatic tires as described above, conductive threads are attached continuously in advance to the outer surface of a rubber material such as a carcass ply, but there was a problem that the conductive threads would fall off from the outer surface of the material during the tire manufacturing process.

[0005] The present disclosure has been devised in consideration of the above-described situation, and has as its main objective the provision of a tire manufacturing method that can prevent conductive threads from falling off from the outer surface of the rubber material during the manufacturing process. [Means for solving the problem]

[0006] The present disclosure relates to a method for manufacturing a tire, the method including a first step of attaching conductive thread to an outer surface of an unvulcanized rubber material constituting the tire to reduce the electrical resistance of the tire, the first step including a step of heating the outer surface of the rubber material prior to arranging the conductive thread and / or simultaneously with arranging the conductive thread on the outer surface of the rubber material. Effect of the Invention

[0007] By adopting the above-described configuration, the tire manufacturing method of the present disclosure can effectively prevent the conductive threads from falling off from the outer surface of the rubber material during the manufacturing process. [Brief description of the drawings]

[0008] [Figure 1] 1 is a meridian cross-sectional view of a tire manufactured by the manufacturing method of this embodiment. FIG. [Diagram 2] FIG. 2 is a perspective view showing a manufacturing line in a first step of the present embodiment. [Diagram 3] FIG. 3 is an enlarged perspective view of the roller of FIG. 2. [Figure 4] 3 is an enlarged side view of the pressing surface of the roller in FIG. 2. [Diagram 5] FIG. 11 is a perspective view showing a manufacturing line for a first step of another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The present disclosure relates to a method for manufacturing a tire having a conductive thread. The conductive thread can reduce the electrical resistance of the tire and prevent static electricity from accumulating on the vehicle. FIG. 1 shows a meridian cross section of a tire 1 manufactured by the manufacturing method of this embodiment. As shown in FIG. 1, the tire 1 has a carcass 6, and a conductive thread 10 is attached to the outer surface of the carcass 6.

[0010] The carcass 6 includes a carcass ply 6A extending from one bead portion 4 through the tread portion 2 to the other bead portion (not shown). It goes without saying that the carcass ply 6A passes through the sidewall rubber 3G of the sidewall portion 3 between the bead portion 4 and the tread portion 2. The carcass ply 6A is formed, for example, by covering carcass cords arranged in parallel with a topping rubber. The carcass 6 in this embodiment is formed of one carcass ply 6A, but may be formed of a plurality of carcass plies 6A.

[0011] The carcass ply 6A includes, for example, a main body portion 6a and a turned-up portion 6b. The main body portion 6a extends from at least the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4. The turned-up portion 6b is, for example, continuous with the main body portion 6a and turned up around the bead core 5 from the axially inner side to the axially outer side.

[0012] The conductive thread 10 is arranged on the outer surface of the carcass ply 6A, for example, and in this embodiment, extends from one bead portion 4 to the other bead portion (not shown). Note that the conductive thread 10 is shown by a dashed line in FIG. 1. The conductive thread 10 has an electrical resistance per unit length of 10 8 A tire in which such conductive yarn 10 is arranged has a low electrical resistance, and can suppress the accumulation of static electricity in the vehicle.

[0013] The manufacturing method of tire 1 of the present disclosure includes a first step of attaching conductive threads 10 for reducing the electrical resistance of tire 1 to the outer surface of the unvulcanized rubber material that constitutes tire 1. It should be noted that in the manufacturing method of tire of the present disclosure, publicly known matters are applied to matters that are not specifically described.

[0014] FIG. 2 is a perspective view conceptually showing the manufacturing line in the first step. As shown in FIG. 2, the unvulcanized rubber material 15 constituting the tire 1 is fed by the main roller 12. The unvulcanized rubber material 15 means a rubber material in a state in which the rubber is not completely vulcanized and therefore has a sticky outer surface, and includes a semi-vulcanized rubber material. The rubber material 15 of this embodiment is configured as a carcass ply 6A (shown in FIG. 1) and includes a carcass cord therein. However, the present disclosure is not limited to such an embodiment.

[0015] The first step of the present disclosure includes a step of heating the outer surface 16 of the rubber material 15 before arranging the conductive thread 10 and / or at the same time as arranging the conductive thread 10 on the outer surface 16 of the rubber material 15. In the tire manufacturing method of the present disclosure, by adopting the above-mentioned configuration, it is possible to effectively prevent the conductive thread 10 from falling off the outer surface of the rubber material 15 during the manufacturing process. The following mechanism is presumed to be the reason for this.

[0016] As described above, the first step of the present disclosure includes a step of heating the outer surface 16 of the rubber material 15, and therefore the conductive thread 10 is placed when the adhesiveness of the outer surface 16 of the rubber material 15 has been increased by heating. Therefore, it is believed that the rubber material 15 and the conductive thread 10 are securely adhered to each other, and the conductive thread 10 can be effectively prevented from falling off the outer surface 16 of the rubber material 15.

[0017] A more detailed configuration of this embodiment will be described below. Each configuration described below shows a specific aspect of this embodiment. Therefore, it goes without saying that the present disclosure can achieve the above-mentioned effects even if it does not have the configuration described below. In addition, even if any one of the configurations described below is applied alone to the manufacturing method of the present disclosure having the above-mentioned characteristics, an improvement in performance according to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a composite improvement in performance according to each configuration can be expected.

[0018] In the first step shown in Fig. 2, one conductive thread 10 is disposed in the rubber material 15, but Fig. 2 is a simplified drawing for easy understanding of the embodiment. Therefore, multiple conductive threads 10 may be disposed in the rubber material 15. In this case, the multiple conductive threads 10 are disposed side by side in the width direction of the rubber material 15.

[0019] In the present disclosure, the first step may be introduced into any step of the tire manufacturing method. On the other hand, since the rubber material 15 of the present embodiment is applied to the carcass ply, it undergoes an EBR step in which electrons are emitted to the outer surface after topping to moderately promote vulcanization. For this reason, the first step of the present embodiment is preferably applied after this EBR step. This is because if the first step is applied before the EBR step, there is a risk of sparks being generated by the conductive thread 10 during the EBR step. More specifically, the first step of the present embodiment is preferably applied after the EBR step and before the cutting step of the rubber material 15.

[0020] The first step of this embodiment includes a step of pressing the conductive thread 10 against the outer surface 16 of the rubber material 15 with the pressing surface 21 of the roller 20 having a heated pressing surface 21. The pressing surface 21 of the roller 20 is heated to a required temperature as appropriate. That is, in the first step of this embodiment, the roller 20 places the conductive thread 10 on the outer surface 16 of the rubber material 15, and at the same time, the roller 20 heats the outer surface 16 of the rubber material 15. However, the present disclosure is not limited to such an embodiment, and even if the outer surface of the rubber material 15 is heated by some means and then the conductive thread 10 is simply placed on the outer surface 16, the adhesiveness of the rubber material 15 can be expected to prevent the conductive thread 10 from falling off.

[0021] 2, a known means may be appropriately adopted as a heating means for the pressing surface 21, such as controlling the heating by disposing a heating wire inside the roller 20. Also, a known means may be appropriately adopted as a control means for the heating temperature of the pressing surface 21, such as detecting and controlling the temperature of the pressing surface 21 by a non-contact temperature sensor.

[0022] It is desirable that the temperature of the pressing surface 21 be set to a temperature that can increase the adhesion of the outer surface 16 of the rubber material 15, but does not lead to vulcanization of the rubber material 15. From this viewpoint, the temperature of the pressing surface 21 is desirably 70°C or higher, more desirably 80°C or higher, and desirably 130°C or lower, more desirably 120°C or lower.

[0023] The roller 20 presses the conductive yarn 10 with a pressure that ensures that the conductive yarn 10 adheres to the outer surface of the rubber material 15 and does not excessively deform the rubber material 15. From this perspective, the pressure with which the roller 20 presses the conductive yarn 10 is preferably 0.1 to 2.0 MPa, and more preferably 0.2 to 1.0 MPa.

[0024] Fig. 3 shows an enlarged perspective view of roller 20. Fig. 4 shows an enlarged side view of pressing surface 21 of roller 20. As shown in Fig. 3 and Fig. 4, roller 20 is configured in a cylindrical shape, and its outer circumferential surface is configured as pressing surface 21.

[0025] As a more preferable aspect, the pressing surface 21 of the present embodiment is provided with a plurality of ridges 23 extending in a direction intersecting the roller circumferential direction. The conductive yarn 10 pressed by the roller 20 having such ridges 23 is easily adhered to the rubber material 15, and the falling off of the conductive yarn 10 is further suppressed.

[0026] 4, from the viewpoint of suppressing excessive deformation of the outer surface of the rubber material 15 while exerting the above-mentioned effects, the height h1 of the ridges 23 is, for example, 0.1 to 1.5 mm, and preferably 0.2 to 1.1 mm. From the same viewpoint, the distance L1 between two adjacent ridges 23 is, for example, 0.3 to 2.5 mm, and preferably 1.0 to 1.6 mm. The distance L1 corresponds to the distance between the apexes of the two ridges 23 in the roller circumferential direction.

[0027] Conventionally, there was a problem that conductive threads containing metal materials were easily dropped off from the outer surface of the rubber material during the manufacturing process, making them difficult to adopt. On the other hand, in the manufacturing method disclosed herein, even conductive threads containing metal materials can be sufficiently prevented from dropping off. Therefore, the conductive thread 10 may contain a metal material. In a more preferable embodiment, the conductive thread 10 of the present embodiment contains a metal material and a resin material. In such conductive threads 10, the metal material increases the conductivity, while the resin material ensures adhesion with the rubber material. Therefore, in the manufacturing method of the present embodiment, tires with excellent conductivity can be manufactured with a low defect rate.

[0028] For example, a polyester material is used as the resin material of the conductive yarn 10. For example, SUS is used as the metal material of the conductive yarn 10. As a more preferable embodiment, the conductive yarn 10 of the present embodiment is a blended yarn containing PET staple fibers and SUS staple fibers.

[0029] The conductive thread 10 of the present embodiment preferably contains 10% to 30% by weight of metal material. Such conductive thread 10 is less likely to fall off from the rubber material 15 and can exhibit excellent conductivity.

[0030] Fig. 5 is a perspective view conceptually showing a manufacturing line in the first step of another embodiment of the present disclosure. As shown in Fig. 5, in the first step of this embodiment, the outer surface 16 of the rubber material 15 is heated before the conductive thread 10 is arranged. Even in such an embodiment, the falling off of the conductive thread 10 can be effectively suppressed.

[0031] In this embodiment, a heating roller 26 for heating the outer surface 16 of the rubber material 15 and an adhesion roller 27 for adhering the conductive thread 10 to the outer surface of the rubber material 15 are separately arranged. In this embodiment, the conductive thread 10 does not come into contact with the heating roller 26, so that it is possible to suppress contraction of the resin material of the conductive thread 10 due to heat. Note that the adhesion roller 27 can be configured with the protrusions 23 of the roller 20 shown in Figures 3 and 4.

[0032] The means for heating the outer surface 16 of the rubber material 15 is not limited to the heating roller 26. For example, the falling off of the conductive yarn 10 can be suppressed even if the outer surface 16 of the rubber material 15 is heated with a non-contact heater or a hot air dryer (not shown).

[0033] Although several embodiments of the tire manufacturing method according to the present disclosure have been described in detail above, the present disclosure is not limited to the above specific embodiments and can be modified in various aspects. EXAMPLES

[0034] As an embodiment, a manufacturing method was prepared in which conductive threads were arranged on the outer surface of a rubber material in the manner shown in FIG. 2 or FIG. 5. Also, as a comparative example, a manufacturing method was prepared that did not include the first step of the present disclosure. The comparative example and each embodiment are substantially the same manufacturing method, except for matters related to the first step. The comparative example and each embodiment were tested for the frequency of conductive threads falling off and the retention strength of the conductive threads. The test method is as follows.

[0035] <Frequency of conductive thread falling off> For the comparative example and each example, the number of times the conductive yarn fell off when operated for the same period of time was measured.

[0036] <Retention power of conductive thread> For the comparative example and each example, an unvulcanized rubber material with a conductive thread disposed thereon was taken, and the maximum stress when the conductive thread was peeled off from the rubber material was measured. The results are shown as an index with the maximum stress of the comparative example being set at 100. The larger this index is, the better the retention force of the conductive thread is, and thus the more reliably the conductive thread can be prevented from falling off. The test results are shown in Table 1.

[0037] [Table 1]

[0038] As shown in Table 1, in the comparative example, the conductive thread fell off eight times when operated for the same time, whereas in each of the examples, no conductive thread fell off. In addition, the retention strength of the conductive thread in the comparative example was 100 points, whereas the retention strength in each of the examples was 227 to 322 points, indicating that the retention strength of the conductive thread in each of the examples was significantly improved. As described above, it was confirmed that the tire manufacturing method of the present disclosure can effectively prevent the conductive thread from falling off from the outer surface of the rubber material during the manufacturing process.

[0039] [This Disclosure] The present disclosure is as follows: The present disclosure (1) is a method for manufacturing a tire, comprising a first step of attaching conductive threads to an outer surface of an unvulcanized rubber material constituting a tire to reduce the electrical resistance of the tire, the first step including a step of heating the outer surface of the rubber material before arranging the conductive threads and / or at the same time as arranging the conductive threads on the outer surface of the rubber material.

[0040] The present disclosure (2) is the method for producing a tire according to the present disclosure (1), wherein the conductive yarn has a diameter of 0.1 to 0.2 mm.

[0041] The present disclosure (3) is a method for producing a tire according to the present disclosure (1) or (2), wherein the conductive yarn includes a polyester material.

[0042] The present disclosure (4) is a method for producing a tire in any combination with any of the present disclosures (1) to (3), wherein the conductive yarn contains a metal material.

[0043] The present disclosure (5) is the method for producing a tire according to the present disclosure (4), wherein the conductive yarn contains 10% to 30% by weight of the metal material.

[0044] The present disclosure (6) is a method for producing a tire in any combination with any of the present disclosures (1) to (5), wherein the conductive yarn is a blended yarn of PET staple fiber and SUS staple fiber.

[0045] The present disclosure (7) is a tire manufacturing method in any combination with any of the present disclosures (1) to (6), wherein the first step includes a step of pressing the conductive yarn against the outer surface of the rubber material with the pressing surface of a roller having a heated pressing surface.

[0046] The present disclosure (8) is the method for manufacturing a tire according to the present disclosure (7), wherein the temperature of the pressing surface is a temperature at which the rubber material does not reach vulcanization.

[0047] The present disclosure (9) is the method for producing a tire according to the present disclosure (8), wherein the temperature of the pressing surface is 80 to 120°C.

[0048] The present disclosure (10) is a tire manufacturing method in any combination with any of the present disclosures (7) to (9), in which the roller presses the conductive yarn with a pressure of 0.1 to 2.0 MPa.

[0049] The present disclosure (11) is a tire manufacturing method in any combination with any of the present disclosures (7) to (10), wherein the pressing surface is provided with a plurality of protrusions extending in a direction intersecting the roller circumferential direction.

[0050] The present disclosure (12) is the method for producing a tire according to the present disclosure (11), wherein the height of the ridges is 0.2 to 1.1 mm.

[0051] The present disclosure (13) is a method for manufacturing a tire in any combination with any of the present disclosures (1) to (12), wherein the rubber material is a carcass ply.

[0052] The present disclosure (14) is a method for manufacturing a tire in any combination with any of the present disclosures (1) to (13), wherein the rubber material is a carcass ply that has been subjected to an EBR process. [Explanation of symbols]

[0053] 1 Tire 10 Conductive thread 15 Rubber materials 16 Outer surface of rubber material

Claims

1. A method for manufacturing a tire, comprising: The method includes a first step of attaching conductive threads for reducing the electrical resistance of a tire to an outer surface of an unvulcanized rubber material constituting a tire, The first step includes a step of heating the outer surface of the rubber material before disposing the conductive thread and / or at the same time as disposing the conductive thread on the outer surface of the rubber material. A method for manufacturing tires.

2. The method for manufacturing a tire according to claim 1, wherein the conductive thread has a diameter of 0.1 to 0.2 mm.

3. The method of claim 1 or 2, wherein the conductive yarn comprises a polyester material.

4. The method for manufacturing a tire according to claim 1 , wherein the conductive yarn includes a metal material.

5. The tire manufacturing method according to claim 4 , wherein the conductive yarn contains 10% to 30% by weight of the metal material.

6. The method for manufacturing a tire according to claim 1 , wherein the conductive yarn is a blended yarn of PET short fiber and SUS short fiber.

7. The method for manufacturing a tire according to claim 1 , wherein the first step includes a step of pressing the conductive thread against the outer surface of the rubber material with a pressing surface of a roller having a heated pressing surface.

8. The method for manufacturing a tire according to claim 7 , wherein the temperature of the pressing surface is a temperature at which the rubber material does not reach vulcanization.

9. The method for manufacturing a tire according to claim 8, wherein the temperature of the pressing surface is 80 to 120°C.

10. The tire manufacturing method according to any one of claims 7 to 9, wherein the roller presses the conductive yarn with a pressure of 0.1 to 2.0 MPa.

11. The tire manufacturing method according to claim 7 , wherein the pressing surface is provided with a plurality of ridges extending in a direction intersecting with the circumferential direction of the roller.

12. The method for manufacturing a tire according to claim 11, wherein the height of the ridge is 0.2 to 1.1 mm.

13. The method for manufacturing a tire according to claim 1 , wherein the rubber material is a carcass ply.

14. The method for manufacturing a tire according to any one of claims 1 to 13, wherein the rubber material is a carcass ply that has been subjected to an EBR process.

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