Tire manufacturing method

Abstract

To provide a manufacturing method of a tire, the method enabling suppression of the occurrence of defect in a shoulder land of a tread.SOLUTION: A manufacturing method of a tire comprises the steps of: winding a ribbon rubber in a tire circumferential direction thereby forming a tread rubber; and vulcanizing an unvulcanized tire comprising the tread rubber. The vulcanized tire comprises: a plurality of major grooves extending in the tire circumferential direction; and a plurality of lands which are partitioned by the plurality of major grooves and a pair of ground contact ends. The plurality of lands include shoulder lands which are arranged at the outmost side in a tire axial direction. The ribbon rubber forming at least a part of the shoulder land comprises: a base material; and a pressure-sensitive adhesive which coats at least a part of the outer periphery of the base material and has larger adhesive strength than that of the base material.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] Conventionally, for example, a tire manufacturing method includes a step of forming tread rubber by winding ribbon rubber in the tire circumferential direction (for example, Patent Document 1). When an unvulcanized tire is vulcanized, the shoulder region of the tread rubber is generally significantly deformed (for example, expanded). Therefore, defects such as gaps, cracks, and air pockets between the ribbon rubbers are likely to occur in the shoulder region of the tread. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-121694 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a tire manufacturing method that can suppress the occurrence of defects in the shoulder land of the tread. [Means for solving the problem]

[0005] The tire manufacturing method includes a step of forming tread rubber by winding ribbon rubber in the circumferential direction of the tire, and a step of vulcanizing an unvulcanized tire comprising the tread rubber, wherein the vulcanized tire comprises a plurality of main grooves extending in the circumferential direction of the tire and a plurality of lands defined by the plurality of main grooves and a pair of ground contact edges, the plurality of lands including shoulder lands located at the outermost positions in the axial direction of the tire, and the ribbon rubber that will form at least a portion of the shoulder lands comprises a substrate and an adhesive material that covers at least a portion of the outer periphery of the substrate and has an adhesive strength greater than that of the substrate. [Brief explanation of the drawings]

[0006] [Figure 1] Cross-sectional view of a vulcanized tire in the tire meridian plane [Figure 2] Enlarged view of the main part of Figure 1 [Figure 3] Front view of the main part of the tire building device [Figure 4] FIG. 1 is a perspective view of a main part of the tire manufacturing apparatus; [Figure 5] Cross section of ribbon rubber [Figure 6] Cross-sectional view of a main part of an unvulcanized tire in the tire meridian plane [Figure 7] Enlarged view of the main part of Figure 6 DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, one embodiment of a tire and a method for manufacturing a tire will be described with reference to Figures 1 to 7. Note that in each figure, the dimensional ratios in the drawing do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match either.

[0008] First, the configuration of a tire after vulcanization according to this embodiment (hereinafter also referred to as a "vulcanized tire") will be described with reference to FIGS. 1 and 2. FIG.

[0009] 1, the vulcanized tire 1 includes a pair of bead portions 2 each having a bead core, sidewalls 3 extending outward in the tire radial direction D2 from each bead portion 2, and a tread 4 connected to the outer ends of the pair of sidewalls 3 in the tire radial direction D2, the outer surface (tread surface 4a) of which comes into contact with the road surface in the tire radial direction D2. In this embodiment, the vulcanized tire 1 is a pneumatic tire 1 into which air is introduced, and is mounted on a rim 5.

[0010] In each figure, the first direction D1 is the tire axial direction D1 which is parallel to the tire rotation axis which is the center of rotation of the tire 1, the second direction D2 is the tire radial direction D2 which is the diameter direction of the tire 1, and the third direction D3 is the tire circumferential direction D3 around the tire rotation axis.

[0011] The inner side in the tire axial direction D1 is the side closer to the tire equatorial plane S1, and the outer side in the tire axial direction D1 is the side farther from the tire equatorial plane S1. The inner side in the tire radial direction D2 is the side closer to the tire rotational axis, and the outer side in the tire radial direction D2 is the side farther from the tire rotational axis.

[0012] The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and located at the center of the tire axial direction D1 of the tire 1, and the tire meridian plane is a plane that includes the tire rotation axis and is perpendicular to the tire equatorial plane S1.

[0013] The dimensional values, positional relationships, and size relationships of the vulcanized tire 1 described below are measured under normal conditions with the vulcanized tire 1 mounted on a normal rim 5 and inflated to normal internal pressure and no load. A normal rim is a rim defined for each tire 1 by a standard system that includes the standard on which the tire 1 is based; for example, it is a standard rim for JATMA, and a "Measuring Rim" for TRA and ETRTO.

[0014] In addition, it is the air pressure specified for each tire in the standard system including the standard on which tire 1 is based, and for truck / bus tires and light truck tires, it is the maximum air pressure for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO. For passenger car tires, the normal internal pressure is usually 180 kPa, but for tires labeled "Extra Load" or "Reinforced," the normal internal pressure is 220 kPa.

[0015] The vulcanized tire 1 also includes a carcass 6 that is bridged between a pair of bead cores, and an inner liner 7 that is disposed inside the carcass 6 and has an excellent function of preventing gas permeation in order to maintain air pressure. The carcass 6 and the inner liner 7 are disposed along the inner circumference of the tire, spanning the bead portion 2, the sidewall 3, and the tread 4.

[0016] The tread 4 includes a tread rubber 4b having a tread surface 4a that comes into contact with the road surface, and a belt 4c disposed between the tread rubber 4b and the carcass 6. The tread surface 4a has a contact patch that actually comes into contact with the road surface, and the outer ends of the contact patch in the tire axial direction D1 are called contact edges 4d and 4e. The contact patch refers to the tread surface 4a that comes into contact with the road surface when the tire 1 is mounted on a standard rim 5, inflated to the standard internal pressure, placed perpendicularly on a flat road surface, and a standard load is applied.

[0017] The normal load is the load determined for each tire 1 by the respective standards, including the standards on which the tire 1 is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "LOAD CAPACITY" for ETRTO. If the tire 1 is a passenger car tire, the normal load is a load equivalent to 88% of the load, and if the tire 1 is a racing kart tire, the normal load is 392N.

[0018] The tread rubber 4b includes a plurality of main grooves 8, 9, 10 extending in the tire circumferential direction D3, and a plurality of lands 11, 12, 13, 14 defined by the main grooves 8, 9, 10 and the pair of ground contact edges 4d, 4e. Although not particularly limited, for example, as in the present embodiment, the number of main grooves 8, 9, 10 may be three, and the number of lands 11, 12, 13, 14 may be four.

[0019] The main grooves 8, 9, and 10 extend continuously in the tire circumferential direction D3. The main grooves 8, 9, and 10 may have a shallower portion, known as a treadwear indicator (not shown), that becomes exposed as the grooves wear, thereby indicating the degree of wear. For example, the main grooves 8, 9, and 10 may have a groove width that is 3% or more of the distance between the ground contact edges 4d and 4e (the dimension in the tire axial direction D1). For example, the main grooves 8, 9, and 10 may have a groove width that is 5 mm or more.

[0020] The pair of main grooves 8, 9 arranged on the outermost sides in the tire axial direction D1 are referred to as shoulder main grooves 8, 9. Of the shoulder main grooves 8, 9, the main groove 8 arranged on one side (the right side in FIG. 1) is referred to as the first shoulder main groove 8, and the main groove 9 arranged on the other side (the left side in FIG. 1) is referred to as the second shoulder main groove 9. Furthermore, the main groove 10 arranged between the pair of shoulder main grooves 8, 9 is referred to as the center main groove 10.

[0021] The lands 11, 12 defined by the shoulder main grooves 8, 9 and the ground contact edges 4d, 4e are called shoulder lands 11, 12, and the lands 13, 14 defined by a pair of adjacent main grooves 8, 9, 10 are called center lands 13, 14. Of the shoulder lands 11, 12, the land 11 located on one side (the right side in Figure 1) is called the first shoulder land 11, and the land 12 located on the other side (the left side in Figure 1) is called the second shoulder land 12.

[0022] As shown in Fig. 2, the first shoulder land 11 may be formed of, for example, non-conductive rubber 15 and conductive rubber 16, as in this embodiment. As a result, a portion of the tread surface 4a of the first shoulder land 11 is formed of conductive rubber 16. In Fig. 2 (as in Fig. 1), the conductive rubber 16 is shown by a solid line, and the rubber in other portions is non-conductive rubber 15.

[0023] Regardless of whether it is before or after vulcanization, the volume resistivity of the conductive rubber 16 is smaller than the volume resistivity of the non-conductive rubber 15. For example, the conductive rubber 16 has a volume resistivity of 10 8Examples of the non-conductive rubber 15 include rubbers with a volume resistivity of less than Ω·cm, such as those containing a high proportion of carbon black as a reinforcing agent in the raw rubber. 8 Examples include rubbers that exhibit a resistance of Ω·cm or more, and raw rubbers that contain a high proportion of silica as a reinforcing agent.

[0024] Furthermore, although not particularly limited, the loss tangent of the conductive rubber 16 after vulcanization may be larger than the loss tangent of the non-conductive rubber 15 after vulcanization, for example, as in this embodiment. The loss tangent (tan δ) may be a value measured using a spectrometer manufactured by UBM under conditions of an initial strain of 10%, a dynamic strain of ±1.0%, a frequency of 10 Hz, and a temperature of 60°C.

[0025] Furthermore, although not particularly limited, the rubber hardness of the conductive rubber 16 after vulcanization may be greater than the rubber hardness of the non-conductive rubber 15 after vulcanization, as in the present embodiment. The rubber hardness is JIS K6253-1-2012 3.2 durometer hardness, and is measured in an atmosphere of 23°C using a type A durometer for general rubber (medium hardness).

[0026] However, since the loss tangent of the conductive rubber 16 is large, there is a risk that the rolling resistance of the tire 1 will increase due to the conductive rubber 16. In addition, when traveling straight, the contact length in the tire circumferential direction D3 becomes shorter as one moves further outward in the tire axial direction D1. In response to this, for example, as in this embodiment, the conductive rubber 16 may be arranged only in the outer region 11a of the first shoulder land 11, and not arranged in the inner region 11b of the first shoulder land 11.

[0027] This prevents the area of ​​the conductive rubber 16 that comes into contact with the ground from increasing when traveling straight, thereby preventing an increase in rolling resistance due to the conductive rubber 16. The outer region 11a refers to the outer half of the first shoulder land 11 in the tire axial direction D1 on the tread surface 4a, and the inner region 11b refers to the inner half of the first shoulder land 11 in the tire axial direction D1 on the tread surface 4a.

[0028] Furthermore, since the conductive rubber 16 has a high rubber hardness, it is possible to increase the rigidity of the outer regions 11a of the shoulder lands 11 and 12, particularly the outer regions 11a, in order to withstand the large force applied to the shoulder lands 11 and 12 during cornering. This makes it possible to improve the steering stability during cornering, for example.

[0029] 1 , the conductive rubber 16 on the tread surface 4a may be electrically connected to the rim 5 via a conductive path formed by the carcass 6 and the bead portion 2, as in the present embodiment. In other words, the sidewall 3 may be provided with a sidewall rubber 3a including the outer surface of the sidewall 3, and the sidewall rubber 3a may be formed only from the non-conductive rubber 15.

[0030] As a result, while the sidewall rubber 3a is deformed during running, the sidewall rubber 3a is formed only with the non-conductive rubber 15 having a small loss tangent, and therefore, it is possible to suppress an increase in rolling resistance caused by deformation of the sidewall rubber 3a during running.

[0031] Although not particularly limited, for example, as in the present embodiment, the second shoulder land 12 may also be formed of the non-conductive rubber 15 and the conductive rubber 16, similar to the first shoulder land 11. As a result, a part of the tread surface 4a of the second shoulder land 12 is also formed of the conductive rubber 16.

[0032] Next, the configuration of the tire manufacturing apparatus according to this embodiment and the method for manufacturing the tire 1 will be described with reference to FIGS.

[0033] As shown in Figures 3 to 5, the tire manufacturing apparatus 20 may include, for example, as in this embodiment, a first extrusion section 21 that extrudes rubber to become the substrate 31, a second extrusion section 22 that extrudes rubber to become the adhesive material 32, and a winding section 23 around which the string-like ribbon rubber 30 formed by extrusion from each of the extrusion sections 21, 22 is wound.

[0034] The winding portion 23 may be formed in a cylindrical shape, for example, as in this embodiment, and may be rotatable and displaceable in the tire axial direction D1 relative to the extrusion portions 21, 22. As a result, the extruded and molded ribbon rubber 30 is wound spirally around the outer periphery of the winding portion 23. In this way, the ribbon rubber 30 is wound in the tire circumferential direction D3 to form the tread rubber 4b.

[0035] Although not particularly limited, the cross-sectional shape of the base material 31 may be, for example, as in this embodiment, a substantially triangular shape in which the thickness is greatest at the center in the width direction and the thickness gradually decreases from the center toward both side edges. Furthermore, although not particularly limited, the adhesive material 32 may cover a part of the outer periphery of the base material 31.

[0036] The adhesive strength of the adhesive material 32 is greater than that of the substrate 31. The adhesive strength (N) is determined by, for example, using an adhesive strength measuring device (trade name "Tack Tester II") manufactured by Toyo Seiki Seisaku-sho, Ltd., pressing a test piece (compliant with JIS T9233) made of the rubber to be measured onto a metal plate under conditions of a pressure load of 1 N and a pressure time of 10 seconds, and measuring the force required to peel the test piece from the metal plate at a speed of 30 mm / min.

[0037] Although not particularly limited, in order to increase the adhesiveness of the rubber constituting the adhesive material 32, a tackifier may be added to the rubber raw material and kneaded. Although not particularly limited, the tackifier may be, for example, a synthetic resin-based tackifier such as a phenol resin or an alkylphenol resin, or a natural resin-based tackifier such as a chroman-indene resin or a rosin derivative.

[0038] Note that the tread rubber 44b may be formed, for example, by winding the ribbon rubber 30 over another member that has been wound around the outer periphery of the winding portion 23. Also, for example, after the tread rubber 44b is formed, the tread rubber 44b may be joined to another member (for example, the sidewall rubber 43a, etc.; see FIGS. 6 and 7) so as to be integrated with the other member.

[0039] In this way, an unvulcanized tire 41 (hereinafter also simply referred to as an "unvulcanized tire"; see Figures 6 and 7) is molded. Then, the unvulcanized tire 41 is vulcanized to manufacture a vulcanized tire 1 (see Figures 1 and 2). Note that the adhesive force of the rubber of the adhesive material 32 may be lost by vulcanization.

[0040] Incidentally, for example, by switching the second extrusion unit 22 between a state in which the rubber that becomes the adhesive material 32 is extruded and a state in which the extrusion is stopped, it is possible to change the position where the adhesive material 32 is disposed. This allows the adhesive material 32 to be disposed at a desired position on the unvulcanized tire 41.

[0041] Next, the configuration of the unvulcanized tire 41 according to this embodiment will be described with reference to FIGS.

[0042] As shown in FIG. 6, an unvulcanized tire 41 may have, for example, a bead portion 42, a sidewall 43, and a tread 44, which respectively become the bead portion 2, sidewall 3, and tread 4 of a vulcanized tire 1, as in this embodiment.

[0043] Furthermore, the unvulcanized tire 41 may, for example, as in this embodiment, be provided with a carcass 46, an inner liner 47, a sidewall rubber 43a, a tread surface 44a, a tread rubber 44b, and a belt 44c, which respectively become the carcass 6, inner liner 7, sidewall rubber 3a, tread surface 4a, tread rubber 4b, and belt 4c of the vulcanized tire 1.

[0044] The adhesive material 32 may be disposed in the shoulder region 48 of the tread rubber 44b, for example, as in the present embodiment. That is, the ribbon rubber 30 forming at least a part of the shoulder region 48 may include the adhesive material 32. This makes it possible to improve the adhesion between the ribbon rubbers 30, 30 by the adhesive material 32, thereby suppressing the occurrence of defects in the shoulder region 48 of the tread 44 when manufacturing the tire 1 (for example, when vulcanizing the unvulcanized tire 41).

[0045] The shoulder regions 48 are a pair of regions 48, 48 located on both outer sides in the tire axial direction D1 among regions 48, 48, 49, 49 obtained by dividing the tread surface 44a of the tread rubber 44b into four equal parts in the tire axial direction D1 when no external force is applied to the unvulcanized tire 41. The region 49, 49 located between the pair of shoulder regions 48, 48 is called a center region 49, 49. In Fig. 6 (similarly in Fig. 7), the adhesive material 32 is shown by a solid line, and the rubber in other portions is the base material 31.

[0046] Also, for example, as in this embodiment, the adhesive material 32 may be formed of conductive rubber, and the base material 31 may be formed of non-conductive rubber. This allows the manufacture of an unvulcanized tire 41 having a tread 44 formed of conductive rubber, and the manufacture of a vulcanized tire 1 (see FIGS. 1 and 2) having a tread 4 formed of conductive rubber 16.

[0047] In the tread rubber 44b, the center regions 49, 49 may not include the adhesive material 32 (conductive rubber) as in the present embodiment, but may be formed only of the base material 31 (non-conductive rubber). Also, the sidewall rubber 43a may not include the adhesive material 32 (conductive rubber) as in the present embodiment, but may be formed only of the base material 31 (non-conductive rubber).

[0048] 7, the adhesive material 32 (conductive rubber) may be arranged only in the outer region 48a of the shoulder region 48, and not in the inner region 48b, as in this embodiment. This allows the conductive rubber 16 to be arranged only in the outer region 11a of the shoulder lands 11, 12 in the vulcanized tire 1 (see FIG. 2).

[0049] The outer region 48a of the shoulder region 48 is the outer half of the shoulder region 48 in the tire axial direction D1 on the tread surface 44a when no external force is applied to the unvulcanized tire 41, and the inner region 48b of the shoulder region 48 is the inner half of the shoulder region 48 in the tire axial direction D1 on the tread surface 44a when no external force is applied to the unvulcanized tire 41.

[0050] In this embodiment, each of the pair of shoulder regions 48 includes the adhesive material 32 (conductive rubber), but the present invention is not limited to this configuration. For example, only one of the pair of shoulder regions 48 may include the adhesive material 32 (conductive rubber).

[0051] From the above, as in this embodiment, it is preferable that the manufacturing method of the tire 1 includes a step of forming a tread rubber 44b by winding the ribbon rubber 30 in the tire circumferential direction D3, and a step of vulcanizing the unvulcanized tire 41 having the tread rubber 44b, and the vulcanized tire 1 has a plurality of main grooves 8, 9, 10 extending in the tire circumferential direction D3, and a plurality of lands 11, 12, 13, 14 defined by the plurality of main grooves 8, 9, 10 and a pair of ground contact edges 4d, 4e, the plurality of lands 11, 12, 13, 14 including shoulder lands 11, 12 located at the outermost positions in the tire axial direction D1, and the ribbon rubber 30 that will form at least a part of the shoulder lands 11, 12 includes a base material 31 and an adhesive material 32 that covers at least a part of the outer periphery of the base material 31 and has an adhesive strength greater than that of the base material 31.

[0052] According to this method, the ribbon rubber 30 that will form at least a part of the shoulder lands 11, 12 includes the adhesive material 32 that covers at least a part of the outer periphery of the base material 31, and therefore the adhesive material 32 can improve adhesion between the ribbon rubbers 30, 30. This makes it possible to prevent defects from occurring in the shoulder lands 11, 12 of the tread 4 when manufacturing the tire 1.

[0053] In addition, in the method for manufacturing the tire 1 as in this embodiment, it is preferable that the base material 31 is made of non-conductive rubber and the adhesive material 32 is made of conductive rubber.

[0054] According to this method, since the adhesive material 32 is formed of conductive rubber, not only can defects in the shoulder lands 11, 12 of the tread 4 be suppressed when manufacturing the tire 1, but also a tire 1 having a tread 4 formed of conductive rubber 16 can be manufactured.

[0055] In addition, in the manufacturing method of the tire 1 as in this embodiment, it is preferable that the conductive rubber 16 is disposed only on the outer half of the shoulder lands 11, 12 in the tire axial direction D1.

[0056] According to this method, for example, the loss tangent of the conductive rubber 16 is larger than the loss tangent of the non-conductive rubber 15, and while the contact length in the tire circumferential direction D3 becomes shorter the further outward in the tire axial direction D1 when traveling straight, the conductive rubber 16 is arranged only on the outer half in the tire axial direction D1 of the shoulder lands 11, 12. This makes it possible to prevent the area of ​​the conductive rubber 16 that comes into contact with the ground from becoming larger when traveling straight, and therefore makes it possible to prevent an increase in rolling resistance caused by the conductive rubber 16.

[0057] Furthermore, as in this embodiment, the method for manufacturing the tire 1 preferably further includes a step of forming the sidewall rubber 43a, and the sidewall rubbers 3a, 43a are formed of the non-conductive rubber 15 only.

[0058] According to this method, for example, the loss tangent of the conductive rubber 16 is larger than that of the non-conductive rubber 15, and while the sidewall rubber 3a deforms during driving, the sidewall rubber 3a, 43a is formed only with the non-conductive rubber 15. This makes it possible to suppress an increase in rolling resistance caused by deformation of the sidewall rubber 3a during straight driving.

[0059] The tire 1 and the manufacturing method of the tire 1 are not limited to the configurations of the above-described embodiments, and are not limited to the above-described effects. Furthermore, the tire 1 and the manufacturing method of the tire 1 can, of course, be modified in various ways without departing from the spirit of the present invention. For example, it is of course possible to arbitrarily select one or more of the configurations, methods, etc. according to the various modified examples described below and employ them in the configurations, methods, etc. according to the above-described embodiments.

[0060] (1) In the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the base material 31 is formed of non-conductive rubber, and the adhesive material 32 is formed of conductive rubber. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration.

[0061] For example, the base material 31 may be made of conductive rubber, and the adhesive material 32 may be made of non-conductive rubber. Alternatively, for example, the base material 31 and the adhesive material 32 may each be made of non-conductive rubber. Alternatively, for example, the base material 31 and the adhesive material 32 may each be made of conductive rubber.

[0062] (2) In addition, in the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the conductive rubber 16 is arranged only on the outer half of the shoulder lands 11, 12 in the tire axial direction D1. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration.

[0063] For example, the conductive rubber 16 may be arranged only on the inner half of the shoulder lands 11, 12 in the tire axial direction D1. Alternatively, the conductive rubber 16 may be arranged on both the outer half and the inner half of the shoulder lands 11, 12 in the tire axial direction D1.

[0064] (3) In addition, in the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the adhesive material 32 is arranged only in the outer half of the shoulder region 48 in the tire axial direction D1. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration.

[0065] For example, the adhesive material 32 may be arranged only in the inner half of the shoulder region 48 in the tire axial direction D1. Alternatively, for example, the adhesive material 32 may be arranged across both the outer half and the inner half of the shoulder region 48 in the tire axial direction D1.

[0066] (4) In the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the sidewall rubber 3a, 43a is configured to be formed only from the non-conductive rubber 15. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration. For example, at least a portion of the sidewall rubber 3a, 43a may be configured to be formed from the conductive rubber 16.

[0067] (5) In addition, in the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the adhesive material 32 is configured to cover a part of the outer periphery of the base material 31. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration. For example, the adhesive material 32 may be configured to cover the entire outer periphery of the base material 31.

[0068] (6) Furthermore, in the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the conductive rubber 16 is arranged on the shoulder lands 11 and 12, but not on the center lands 13 and 14. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration. For example, the conductive rubber 16 may be arranged not only on the shoulder lands 11 and 12, but also on the center lands 13 and 14.

[0069] (7) In addition, in the tire 1 and the manufacturing method of the tire 1 according to the above embodiment, the adhesive material 32 is arranged in the shoulder regions 48, 48 but not in the center regions 49, 49. However, the tire 1 and the manufacturing method of the tire 1 are not limited to this configuration. For example, the adhesive material 32 may be arranged not only in the shoulder regions 48, 48 but also in the center regions 49, 49. [Explanation of symbols]

[0070] 1...vulcanized tire, 2...bead portion, 3...sidewall, 3a...sidewall rubber, 4...tread, 4a...tread surface, 4b...tread rubber, 4c...belt, 4d...ground contact edge, 4e...ground contact edge, 5...rim, 6...carcass, 7...inner liner, 8...first shoulder main groove, 9...second shoulder main groove, 10...center main groove, 11...first shoulder land, 11a...outer region, 11b...inner region, 12...second shoulder land, 13...center land, 14...center land, 15...non-conductive rubber, 16...conductive rubber, 20...tire material Manufacturing device, 21...first extrusion section, 22...second extrusion section, 23...winding section, 30...ribbon rubber, 31...substrate, 32...adhesive material, 41...unvulcanized tire, 42...bead section, 43...sidewall, 43a...sidewall rubber, 44...tread, 44a...tread surface, 44b...tread rubber, 44c...belt, 46...carcass, 47...inner liner, 48...shoulder region, 48a...outer region, 48b...inner region, 49...center region, D1...tire axial direction, D2...tire radial direction, D3...tire circumferential direction, S1...tire equatorial plane

Claims

1. A process of forming tread rubber by winding ribbon rubber in the tire circumferential direction; and vulcanizing the unvulcanized tire having the tread rubber, The vulcanized tire has a plurality of main grooves extending in the tire circumferential direction, and a plurality of lands defined by the plurality of main grooves and a pair of ground contact edges, the plurality of lands include a shoulder land disposed at the outermost position in the tire axial direction, The ribbon rubber that will form at least a part of the shoulder land has a base material, an adhesive material that covers at least a part of the outer periphery of the base material and has an adhesive strength greater than an adhesive strength of the base material; the substrate is formed of a non-conductive rubber, the adhesive material is formed of conductive rubber, A method for manufacturing a tire, wherein the conductive rubber is arranged only on an outer half of the shoulder land in the axial direction of the tire.

2. Further comprising the step of forming a sidewall rubber, The tire manufacturing method according to claim 1 , wherein the sidewall rubber is formed solely from non-conductive rubber.

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