WO2008038463A1 - Pneumatic tire - Google Patents

Abstract

A pneumatic tire that can be manufactured according to a conventional process not requiring any special tire manufacturing step and not needing any addition of material members and process steps, and that not only excels in rolling resistance and wet properties but also exhibits electrical conductivity. The pneumatic tire is one having rim strip (19) fitted to bead part (11) and side wall part (16) being in contact with the rim strip (19), the side wall part (16) extending outward in the direction of tire radius from the bead part (11) and constructing a ground contact edge region of tread part (13), characterized in that on the circumference of unilateral or ambilateral side portions of the tire (10), the rim strip (19) and the side wall part (16) are formed into a continuous electricity conducting path by means of a conductive rubber material, and that only the electricity conducting path is used as an energizing path of the tire (10), and that a material selected from among conductive rubber material and nonconductive rubber material is used in members other than the energizing path.

Description

 Specification

 Pneumatic tire

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a pneumatic tire, and more specifically, has a tread made of silica or the like, improves tire rolling resistance and wet performance, and discharges static electricity charged to a vehicle to a road surface. The present invention relates to a pneumatic tire manufactured by a conventional method.

 Background art

 [0002] In order to improve the rolling resistance of pneumatic tires and the running performance on wet road surfaces (wet performance), a technique for blending silica instead of conventional carbon black as a reinforcing agent in a tread rubber composition has become known. /! Along with this silica compounding technology, the static charge charged on the vehicle causes a discharge phenomenon when the tire passes over a manhole or the like, causing problems such as radio noise, adverse effects on electronic circuit components, and short circuits. Get ready!

 [0003] Conventionally, in order to solve the problem of force, a technique has been proposed in which a conductive member in which carbon black is blended in a part of the tread structure is provided to ensure the conductivity of the tire. For example, the technique of Patent Document 1 below describes that a conductive thin film containing carbon black is laid on the outer surface of a tread and a sidewall and discharged through this conductive layer. In the technique of Patent Document 2, a conductive insert is provided on the tire crown from the tread surface to the bottom surface, and a conductive strip made of a conductive material in contact with the insert contacts the wheel in the conductive bead region. It is disclosed that static electricity is discharged by being in a state.

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 8-230407

 Patent Document 2 Japanese Unexamined Patent Publication No. 2006-143208

 Disclosure of the invention

 Problems to be solved by the invention

[0005] However, in the technique of Patent Document 1, the effect of improving the tread rolling resistance and wet performance due to the silica compound is reduced by laying the conductive thin film containing the carbon black, and the original effect is sufficiently exhibited. It's getting harder. Conductive thin film containing carbon black Since the membrane is laid on the outer surface of the tread and sidewalls, additional members and processes are required, and productivity and cost increase are expected.

[0006] The technique of Patent Document 2 requires a separate conductive insert and strip, which increases the number of parts and requires a special process to be easy to manufacture. A decline in sex is expected.

 [0007] In view of the above problems, an object of the present invention is to provide a rolling force ^ resistance that can be manufactured by a conventional method without the need for a special tire manufacturing process and without the addition of a member process. A pneumatic tire having excellent wet performance and conductivity is provided. Means for solving the problem

[0008] The invention described in claim 1 includes a rim strip disposed in a bead portion and a sidewall that contacts the rim strip and extends outward from the bead portion in the tire radial direction and is connected to a ground contact end region of the tread portion. A pneumatic tire having a portion, wherein at least a surface portion of the rim strip, the sidewall portion, and the ground contact end region is continuously formed by a conductive rubber material on a circumference of a side portion on one side or both sides of the tire. The conductive path is used as a current path for the tire, and other members than the current path are selected from a conductive rubber material or a non-conductive rubber material. It is a pneumatic tire.

 [0009] The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the tire radial outer end force of the sidewall portion is integrally formed with the ground contact end region.

[0010] The invention described in claim 3 includes wings that are disposed at both ends of the tread portion in the tire axial direction and that form a surface portion of the ground contact end region in contact with the sidewall portion. 2. The pneumatic tire according to claim 1, wherein

[0011] The invention according to claim 4 is characterized in that the conductive rubber material is a rubber composition having an electrical resistivity of less than 10 ⁸ Ω 'cm. It is a pneumatic tire.

[0012] The invention according to claim 5 is characterized in that the rubber composition comprises a gen-based rubber as a rubber component, and nitrogen adsorption specific surface area of 25 to 100 m ² / g of carbon black is 14 volumes of the whole rubber composition. The pneumatic tire according to claim 4, wherein the pneumatic tire is contained in an amount of at least%.

[0013] The invention according to claim 6 is the pneumatic tire according to claim 1, wherein the non-conductive rubber material comprises a rubber composition containing a non-carbon black reinforcing agent as a reinforcing agent. It is.

 [0014] The invention according to claim 7 is the pneumatic tire according to claim 6, wherein the non-carbon black reinforcing agent is silica.

 The invention's effect

 [0015] In the pneumatic tire of the present invention, the sidewall, the rim strip, and the wing are each formed of one type of rubber composition on the circumference of the tire by a conventional method, and thus disclosed in the prior art. It does not require a special tire manufacturing process, and it can be manufactured by conventional methods without the need for additional member processes. Excellent rolling force due to silica compounding etc. ^ Equipped with resistance and wet performance. Tires can be provided, and noise caused by static electricity charged on a vehicle using a non-conductive tire such as a silica compound, adverse effects on electronic parts, and short-circuit problems can be solved.

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described.

 [0017] (First embodiment)

 FIG. 1 is a half sectional view showing a pneumatic tire 10 of the first embodiment.

 [0018] A pneumatic tire (hereinafter, a pneumatic tire is simply referred to as a "tire") 10 includes a pair of bead portions 11 that are assembled into a rim, and sidewalls that extend outward from the bead portions 11 in the tire radial direction. Portion 16 and a tread portion 13 that contacts the road surface provided between the sidewall portions 16 and 16, and the tread portion 13 includes a crown portion 15 that forms a main contact portion at the center in the tire width direction, and a tread. The shoulder portion 17 is located on both sides of the portion 13 and forms a ground end region and continues to the sidewall portion 16.

 [0019] The tire 10 includes a rim strip 19 that comes into contact with the flange of the rim disposed on the outer side in the tire axial direction of the bead portion 11, and the lower end portion of the sidewall portion 16 overlaps and contacts the end portion of the rim strip 19. is doing.

[0020] Further, as shown in FIG. 1, the tire 10 has an outer end portion in the tire radial direction of the sidewall portion 16. Force S tread rubber 21 A side wall on tread (SWOT) structure is built on top of the end. That is, the outer end portion force of the sidewall portion 16 forms a shoulder portion 17 that covers the surface of both peripheral portions of the tread portion 13 and serves as a tread grounding end region on the tire circumference.

[0021] Further, the tire 10 has two carcass plies made of cords arranged in a radial direction around the bead cores 12 embedded in the pair of bead portions 11, folded back from the inside of the tire to the outside and locked. Carcass 14, belt 18 composed of two cross belt plies arranged inside the tread portion 13, and the outer periphery of the belt 18 spirally wound at an angle of approximately 0 ° with respect to the tire circumferential direction. The figure shows a radial tire for a passenger car with a single cap ply 20 made of a twisted cord.

 [0022] The carcass ply of the carcass 14 includes organic fiber cords such as polyester, nylon, and rayon, the belt ply of the belt 18 includes rigid cords such as steel cord and aramid fiber, and the cap ply 20 includes Is relatively large in heat shrinkage of nylon, polyester, etc., and cords are used as reinforcing materials!

 [0023] The tread rubber 21 of the crown portion 15 that forms the main ground contact portion of the tread portion 13 contributes to improvement of the rolling resistance and wet performance of the tire 10, so that the tan δ of the rubber composition is lowered. For example, a rubber composition containing a non-carbon black reinforcing agent such as precipitated silica, silica such as anhydrous caic acid, clay such as calcined clay or hard clay, or non-carbon black reinforcing agent such as calcium carbonate by replacing with conventional carbon black. used. In particular, silica is preferably used because of its large improvement effect such as rolling resistance.

 [0024] The amount of the non-carbon black reinforcing agent such as silica is usually 30 to 100 parts by weight, preferably 40 to 40 parts by weight based on 100 parts by weight of the rubber component, although it depends on the type and substitution amount of the carbon black. Blended in 80 parts by weight.

[0025] In the case of silica, the type of silica is not particularly limited, but wet silica with a nitrogen adsorption specific surface area (BET) of 100 to 250 m ² / g and a DBP oil absorption of 100 ml / 100 g or more is used as a reinforcing effect and additive. Commercially available products such as Nipsil AQ and VN3 manufactured by Tosoh Silica Industry Co., Ltd., and Ultrazil VN3 manufactured by Degussa, which are preferable from the viewpoint of the above, can be used. In addition, it is preferable to use a silane coupling agent such as bis (triethoxysilylpropyl) monotetrasulfide. [0026] SAF, ISAF, HAF, etc. are preferred as carbon black in the tread rubber 21 from the viewpoint of wear resistance and heat generation!

 [0027] The rubber composition of the tread rubber 21 is a rubber component such as natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), etc. Commonly used in blend rubber. Further, softeners such as oils and waxes for rubber compounding agents, stearic acid, zinc white, resins, anti-aging agents, vulcanizing agents such as sulfur, vulcanization accelerators, and the like are appropriately blended.

[0028] Thereby, the tread rubber 21 becomes a non-conductive rubber with a force resistance that improves rolling resistance and wet performance, whereas the electrical resistivity of the rubber composition becomes 10 ⁸ Ω'cm or more. As a result, the tire 10 becomes non-conductive at the tread grounding portion, and the tire becomes a non-conductive tire with an electric resistance of 10 ⁹ Ω or more by combining the members, and the rim strip rubber 23 and the side of the bead portion 11 Even if conductive rubber is used for the side wall rubber 22 of the wall portion 16, static electricity charged to the vehicle cannot be discharged from the tread portion 13 to the road surface.

[0029] In order to solve the problem of static electricity withstanding the vehicle, the tire 10 of the present embodiment is provided with a sidewall rubber 22 and a rim strip rubber 23 on the circumference of the tire 10 on at least one side portion of the tire. Conductive rubber with an electrical resistivity of less than 10 ⁸ Ω'cm is applied. As a result, the rim strip rubber 23 and the side wall rubber 22 are formed in a continuous conductive path.

 The tire 10 uses only the conductive path as an energization path, and static electricity charged to the vehicle is an outer end portion of the side wall rubber 22 that forms a ground end region through the rim strip rubber 23 and the side wall rubber 22 from the rim. It is discharged from the shoulder 17 to the road surface.

[0031] Such a conductive rubber composition can be easily obtained by appropriately adjusting the blending amount of carbon black. Preferably, the electrical resistivity of the rubber composition is less than 10 ⁷ Ω'cm. Is desirable.

[0032] The conductive side wall rubber 22 includes NR, IR, SBR, BR, syndiotactic

Alternatively, the blend is a rubber component, and the nitrogen adsorption specific surface area (N SA) force is 5 to 100m ² / g

 2

Carbon black is contained in an amount of 14% by volume or more based on the total rubber composition. [0033] When the amount of carbon black is less than 14% by volume, the electrical resistivity of the rubber composition becomes 10 ⁸ Ω'cm or more, and the conductivity deteriorates. If the NSA of carbon black is less than 25m ² / g

 2

The durability of the rubber composition is lowered due to the decrease in strength, and when it exceeds 100 m ² / g, the hysteresis loss increases and the rolling force ^ resistance and heat generation increase.

[0034] NSA 25 ~; 100m ² / g carbon black, HAF, FEF, GPF grade car

 2

 Bon black is mentioned.

 [0035] Further, as a non-carbon black reinforcing agent, silica, clay, calcium carbonate or the like may be used in combination with carbon black in an appropriate amount. Further, a rubber compounding oil, a softening agent such as wax, stearic acid, Zinc white, resins, anti-aging agents, vulcanizing agents such as sulfur, and vulcanization accelerators are appropriately blended.

 [0036] The current-carrying path of the tire 10, that is, members other than the rim strip rubber 23 and the side wall rubber 22 should not have a current-carrying path! /, Selected from conductive rubber material or non-conductive rubber material in a range Can be used.

[0037] For example, when the conductive sidewall rubber 22 is applied only to one side portion of the tire 10, a non-conductive rubber having an electrical resistivity of 10 ⁸ Ω'cm or more is applied to the other side portion. It can also be applied. Thereby, the rolling resistance and wet performance of the tire 10 can be improved by increasing the amount of non-conductive rubber used. In this case, the electrical resistance of the tire 10 is slightly increased as compared with the case where conductive rubber is applied to both side portions, but the discharge property of static electricity is not significantly reduced, and there is no practical problem.

[0038] The non-conductive side wall rubber can be obtained by changing only the blending amount of the conductive rubber and carbon black. That is, N SA is 25 ~; 100m ² / g carbo

 2

A rubber composition down black is contained less than 14 volume _^0/0 of the total rubber composition.

[0039] If the amount of carbon black is 14% by volume or more, the electrical resistivity of the rubber composition is less than 10 ⁸ Ω'cm, and the effect of improving the force rolling resistance that becomes conductive cannot be obtained.

[0040] Further, as the conductive rim strip rubber 23, NR, IR, SBR, BR, VCR and other gen-based rubbers are used alone or in a blend, and the NSA is 70 to 100 m ² / g. Carbo

 2

 14% by volume or more of the entire rubber composition.

[0041] When the amount of carbon black is less than 14% by volume, the electrical resistivity of the rubber composition is 10 ⁸ Ω'cm. As a result, the conductivity deteriorates. Also, if the NSA of carbon black is less than 70m ² / g

 2

Reduced wear resistance of the rubber composition makes it easy to cause bead damage due to rubbing of the rim, and when it exceeds 1 OOm ² / g, hysteresis loss deteriorates and rolling resistance and heat generation increase.

[0042] Carbon black with N SA of 70-100m ² / g is HAF grade carbon black

 2

 Is mentioned.

 [0043] Further, as a non-carbon black reinforcing agent, silica, clay, calcium carbonate and the like may be used in combination with carbon black in appropriate amounts. Zinc white, resins, anti-aging agents, vulcanizing agents such as sulfur, and vulcanization accelerators are appropriately blended.

 [0044] When conductive rubber is applied to only one of the sidewall portions 16, the conductive rubber is also applied to the rim strip rubber 23 on the same side. That is, the conductive property of the tire can be ensured by applying the conductive rubber to the sidewall rubber 22 and the rim strip rubber 23 in pairs on one or both side portions of the tire 10.

 [0045] Further, in the tire 10 shown in FIG. 1, the tread rubber 21 shows a tread having a single structure. When the 1S tread portion 13 has a cap / base structure, the cap rubber has rolling resistance and wet performance. Force to which non-conductive rubber is applied from the viewpoint The base rubber can be appropriately selected from conductive or non-conductive rubber. Also, other parts such as tire 10 carcass, belt topping rubber, bead filler, etc. should not have an energization path! / In the range, it can be selected from conductive or non-conductive rubber as appropriate S, rolling resistance and wet From the viewpoint of improving the performance, it is preferable to select a non-conductive rubber.

 [0046] (Second Embodiment)

 FIG. 2 is a half sectional view showing the pneumatic tire 30 of the second embodiment.

 [0047] The tire 30 is grounded to a pair of bead portions 31 to be rim assembled, a sidewall portion 36 extending outward in the tire radial direction from the bead portion 31, and a road surface provided between the sidewall portions 36, 36. The tread portion 33 includes a crown portion 35 that forms a main ground contact portion at the center in the tire width direction, and a shoulder portion that is located on both sides of the tread portion 33 to form a ground contact end region and continues to the side wall portion 36. 37 and power.

[0048] The tire 30 is a rim strut that contacts a flange of a rim disposed on the radially outer side of the bead portion 31. The lip 39 is provided, and the lower end portion of the side wall portion 36 is in contact with the rim strip 39 end portion.

 [0049] As shown in FIG. 2, the tire 30 has a tread over sidewall (TOS) structure in which both end portions of the tread portion 33 are overlapped with and overlapped with outer end portions of the sidewall portions 36.

[0050] The tread portion 33 is positioned on the shoulder portion 37 forming the ground contact end region at both ends in the tire axial direction, and is in contact with the sidewall portion 36 to form the surface of the shoulder portion 37.

It is arranged so as to straddle the end of 41 and the end of sidewall rubber 42! /

[0051] Further, the tire 30 has two carcass plies made of cords arranged in a radial direction around the bead cores 32 embedded in the pair of bead portions 31, respectively, folded back from the inside of the tire to the outside and locked. Carcass 34, two belts 38 with belt cross ply force arranged inside the tread 33, and the outer circumference of the belt 38 spirally at an angle of approximately 0 ° with respect to the tire circumferential direction. The figure shows a radial tire for a passenger car having a single cap ply 40 made of a twisted cord.

 [0052] The carcass ply of the carcass 34 has an organic fiber cord such as polyester, nylon, and rayon. The belt ply of the belt ply 38 has a rigid cord force such as a steel cord and aramid fiber. Nylon, polyester, etc. are relatively heat-shrinkable! /, And cords are used as reinforcements! /.

[0053] The tread rubber 41 is replaced with conventional carbon black as a reinforcing agent to reduce the tan δ of the rubber composition in order to contribute to improvement of rolling resistance and wet performance in the same manner as the tire 10 described above. A rubber composition using a non-carbon black reinforcing agent such as clay or calcium carbonate as a reinforcing agent is used, and a rubber composition having the same formulation as the tread rubber 21 described in the first embodiment is used. Non-conductive rubber with electrical resistivity of 10 ⁸ Ω'cm or more.

As a result, the tire 30 becomes non-conductive at the tread ground portion and becomes a non-conductive tire having an electric resistance of 10 ⁹ Ω or more as the tire, and the static electricity charged on the vehicle is transferred from the rim to the bead portion 31. It becomes impossible to discharge from the tread portion 33 to the road surface through the rim strip rubber 43 and the side wall rubber 42 of the side wall portion 36.

[0055] In order to solve the problem of static electricity charged in the vehicle, the tire 30 according to the present embodiment includes a wing rubber 44, a side warnole rubber 42, and a rim strip rubber 43 on at least one side portion of the tire. In any case, conductive rubber with an electrical resistivity of less than 10 ⁸ Ω'cm is suitable.

It is formed in a continuous conductive path.

The tire 30 uses only the conductive path as an energization path, and the static electricity charged to the vehicle forms a grounding end region from the rim through the rim strip rubber 43, the side wall rubber 42, and the wing rubber 44. It is discharged to the road surface from the shoulder 17 which is the outer edge of the road.

[0057] Such a conductive rubber composition can be easily obtained by appropriately adjusting the blending amount of carbon black. Preferably, the electrical resistivity of the rubber composition is less than 10 ⁷ Ω'cm. Is desirable.

[0058] For the conductive sidewall rubber 42 and rim strip rubber 43, a rubber composition having the same formulation as the sidewall rubber 22 and rim strip rubber 23 described in the first embodiment is used. Conductive rubber with electrical resistivity of less than 10 ⁸ Ω'cm.

[0059] In addition, as the conductive wing rubber 44, carbon rubber having a NSA of 25 to 100 m ² / g, which is composed of a single or blend of GEN rubbers such as NR, IR, SBR, BR and VCR.

 2

Rack rubber composition is applied that contains 14 volume _^0/0 or more of the entire rubber composition.

[0060] If the amount of carbon black is less than 14% by volume, the electrical resistivity of the rubber composition becomes 10 ⁸ Ω'cm or more, and the conductivity deteriorates. If the NSA of carbon black is less than 25m ² / g

 2

Durability decreases due to the strength reduction of the rubber composition, and when it exceeds 100 m ² / g, hysteresis loss deteriorates and rolling force, resistance and heat generation increase.

[0061] NSA 25 ~; 100m ² / g carbon black, HAF, FEF, GPF grade car

 2

 Bon black is mentioned.

[0062] As a non-carbon black reinforcing agent, silica, clay, calcium carbonate or the like may be used in combination with a single bon black. Further, rubber compounding agents such as oils and waxes are softening agents. , Stearic acid, zinc white, resins, anti-aging agent, vulcanizing agent such as sulfur, vulcanization accelerator and the like are appropriately blended.

 [0063] The conductive path of the tire 30, that is, the rim strip rubber 43, the side wall rubber 4, and the wing rubber 44 other than the conductive rubber material or the non-conductive rubber material as long as the conductive path is not provided. You can choose from and use.

[0064] For example, when conductive side wall rubber 42, rim strip rubber 43 and wing rubber 44 are applied only to one side portion of tire 30, a non-carbon black reinforcing agent is applied to the other side portion. Non-conductive rubber with a compounded electrical resistivity of 0 ⁸ Ω'cm or more may be applied. Thereby, the rolling resistance and wet performance of the tire 30 can be improved. In this case, the electrical resistance of the tire is slightly increased as compared with the case where conductive rubber is disposed on both side portions, but the discharge property of static electricity is not greatly reduced and is not practically affected.

[0065] The non-conductive wing rubber 44 can be obtained by changing only the blending amount of the conductive wing rubber and carbon black. That is, N SA is 25 ~; 100m ² / g

 2

A rubber composition in which carbon black is contained in less than 14 volume _^0/0 of the total rubber composition.

[0066] When the amount of carbon black is 14% by volume or more, the electrical resistivity of the rubber composition becomes less than 10 ⁸ Ω'cm and becomes conductive, but the effect of improving rolling resistance cannot be sufficiently obtained.

[0067] It is needless to say that the conductive rubber is applied to the three members of the side wall rubber 42, the rim strip rubber 43 and the wing rubber 44 in order to secure the conductivity of the tire 30.

 [0068] Further, in the tire 30, when the tread portion 33 has a cap / base structure, the cap is a force to which non-conductive rubber is applied. The base is appropriately selected from conductive or non-conductive rubber. it can. In addition, other parts such as tire 30 carcass, belt topping rubber, bead filler, etc. should not have a current-carrying path! / In the range, it can be selected appropriately from conductive or non-conductive rubber, but rolling resistance and wet performance It is preferable to select non-conductive rubber from the viewpoint of improving the quality.

 [0069] (Third embodiment)

The third embodiment is an example in which the method for forming the sidewall portion is changed. Is described using a cross-sectional view of the tire 10 of FIG.

[0070] In the first and second embodiments, the side wall portions 16 and 36 are formed of a single-piece belt-shaped side wall rubber formed by extrusion molding conductive or non-conductive rubber into a predetermined cross-sectional shape. Sometimes affixed to both sides.

[0071] In the present embodiment, a ribbon-shaped strip rubber that continuously includes a conductive rubber having an electrical resistivity of less than 10 ⁸ Ω 'cm in the longitudinal direction is used as a rim strip 19 for the bead portion 11 at the time of green tire molding. The side wall part 16 is wound continuously and spirally in the substantially circumferential direction of the side wall part 16 to form the side wall part 16 in a predetermined cross-sectional shape. This is a molding method called a method.

[0072] The ribbon-shaped strip rubber may be made of conductive rubber as a whole, but the conductive rubber is continuously included in the longitudinal direction in a part of the ribbon-shaped cross section made of non-conductive rubber. It may be a thing.

 In the latter case, the conductive rubber portion is in contact with the rim strip 19 and is exposed to the surface of the grounding portion with the shoulder portion 17. As a result, an energization path in which conductive rubber is spirally arranged in the sidewall portion 16 is formed, and the static electricity of the vehicle can be discharged to the road surface through the strip rubber. In this case, a rubber composition that can contribute to improvement in rolling resistance and the like can be used as the non-conductive rubber.

 [0074] Such a double-structured strip rubber is obtained by laminating a ribbon made of conductive rubber and non-conductive rubber. It can also be easily obtained by a twin screw extruder.

 [0075] This strip build method can of course be applied to the tire 30 having the TOS structure shown in FIG. 2, and the rim strip 19 and the wing rubber 44 can also be formed by this strip build method. Furthermore, this method can also be used for molding sidewalls made of non-conductive rubber.

 Example

 Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the examples.

[0077] Table 1 shows a rubber composition for treads containing a conductive rubber and a non-conductive rubber in which the amount of carbon black is adjusted for the rim strip and sidewall rubber compositions, and silica. In accordance with the formulation (parts by weight) described in 1., kneaded by a conventional method using a 200-liter Banbury mixer. The rubber components and compounding agents used are as follows. The volume% of carbon black is a calculated value from the blending amount (parts by weight).

[0078] · Natural rubber (NR): Thai RS S # 3

 .Butadiene rubber (BR): Ube Industries, Ltd. BR150B

 • Styrene butadiene rubber (SBR): JSR Corporation 1502

 'Carbon black for rim strip rubber HAF: Tokai Carbon Co., Ltd. Seest 3

 • Carbon black for sidewall rubber FEF: Tokai Carbon Co., Ltd. Seast SO

 Carbon black for tread rubber IS AF: Tokai Carbon Co., Ltd. Seast 6

 'Silica: Tosoh Silica Industry Co., Ltd. Nipsil AQ

 -Silane coupling agent: Degussa, Si69

 .Aloma Oil: Japan Energy Co., Ltd. X-140

 'Paraffin wax: Nippon Seiki Co., Ltd.

 • Anti-aging agent 6C: Nouchi 6C, Ouchi Shinsei Chemical Co., Ltd.

 • Stearic acid: Norenac S-20, Kao Corporation

 • Zinc Oxide: Mitsui Kinzoku Mining Co., Ltd. Zinc Hua 1

 • Sulfur: Hosoi Chemical Industry Co., Ltd. 5% oil-treated powder sulfur

 • Vulcanization accelerator NS: Ouchi Shinsei Chemical Industry Co., Ltd. Noxeller NS—P

[0079] The electrical resistivity of each rubber composition was measured according to JIS K6911 and is shown in Table 1. The measurement conditions are an applied voltage of 1000V, an air temperature of 25 ° C, and a humidity of 50%.

[0080] [Table 1]

Using the resulting rubber composition, the rim strip rubber and side wall rubber can be either conductive rubber (indicated by “◯” in Table 2) or non-conductive rubber (indicated by “X” in Table 2) according to the combinations shown in Table 2. The radial tire (195 / 65R15 88 S) having the SWOT structure shown in FIG. 1 changed to “Display” was manufactured, and the electrical resistance and rolling resistance were measured by the following methods. Comparative Example 4 is a rim A conductive rubber sheet (electric resistivity = 2 Χ 10 ⁷ Ω.cm) with a thickness of 0.2 mm and a width of 10 cm made of carbon black is applied from the strip to the tread to ensure tire conductivity. The tread rubber shown in Table 1 was used in common for each tire.

 [0082] Also, the carcass is 1670dtex / 2 polyester cord, driving ply 22 cords / 25mm 1 ply, Benoleto is 2 + 2 X 0.25 steel cord, driving density 18 cords / 25mm 2 ply (crossing angle) 45 °), and cap ply used 940dtex / 2 nylon 66 cord, single piece structure with 28 / 25mm driving density.

 [0083] The electrical resistance of the tire is as follows: Tire 10 is mounted on a standard rim R (15 X 6JJ) at a pressure of 200 kPa and mounted on a domestic FF-type passenger car with a displacement of 1600 cc. After the measurement, the measurement was performed based on the “Measurement procedure of tire electrical resistance under load” specified by the German WDK, Blatt 3. That is, as shown in FIG. 3, the rim-assembled tire 10 is vertically grounded at a load of 400 kg on a copper plate 131 installed in an insulating state with respect to the base plate 130, and the central portion of the standard rim R and the copper plate The electrical resistance to 131 was measured using a resistance measuring instrument 132 with an applied voltage of 1000 volts. The temperature at the time of measurement is 25 ° C and the humidity is 50%. The results are shown in Table 2.

 [0084] The rolling resistance is measured by rolling a tire on a standard rim at a pressure of 200 kPa and measuring the rolling resistance.

 Using a single-axis drum tester, rolling resistance was measured at a load of 400 kg and a speed of 60 km / h. Expressed as an index with Comparative Example 1 as 100, the larger the value, the higher the rolling resistance and the lower the fuel efficiency. The results are shown in Table 2.

[0085] [Table 2]

* "!: A conductive rubber sheet is pasted on the side wall surfaces from the rim strip to the tread.

[0086]

 Industrial applicability

[0087] The pneumatic tire of the present invention includes a two-wheeled vehicle such as a motorcycle in addition to a four-wheeled vehicle such as a passenger car,

Use for various vehicles such as three-wheeled vehicles, buses, trucks, trailers and industrial vehicles with more than five wheels.

 Brief Description of Drawings

FIG. 1 is a half sectional view of a pneumatic tire having a SWOT structure according to an embodiment.

 FIG. 2 is a half sectional view of a pneumatic tire having a TOS structure according to an embodiment.

 FIG. 3 is a schematic view showing a method for measuring the electrical resistance of a tire.

 Explanation of symbols

[0089] 10 …… Pneumatic tire

 11 …… Bead, club

 13 …… 卜 Red part

 16 …… Sidewall

 17 …… Shoulder

 19 …… Rim strip

Claims

The scope of the claims  [1] A pneumatic tire provided with a rim strip disposed in a bead portion and a sidewall portion that contacts the rim strip and extends from the bead portion outward in the radial direction of the tire and is connected to a ground contact end region of the tread portion. There,  On the circumference of the side part on one or both sides of the tire,  At least a surface portion of the rim strip, the sidewall portion, and the grounding end region is formed by a conductive path made of a conductive rubber material, and only the conductive path is used as a current-carrying path for the tire. Other members are selected from conductive rubber material or non-conductive rubber material.  A pneumatic tire characterized by that.  [2] The tire radial outer end of the sidewall portion integrally forms the ground contact end region.  The pneumatic tire according to claim 1, wherein: [3] It has wings that are arranged at both ends in the tire axial direction of the tread portion and that form a surface portion of the ground contact end region in contact with the sidewall portion  The pneumatic tire according to claim 1, wherein: [4] The conductive rubber material is a rubber composition having an electrical resistivity of less than 10 ⁸ Ω′cm.  The pneumatic tire according to any one of claims 1 to 3, wherein: [5] The rubber composition contains gen-based rubber as a rubber component, and contains carbon black having a nitrogen adsorption specific surface area of 25 to 100 m ² / g of 14% by volume or more based on the total rubber composition.  The pneumatic tire according to claim 4, wherein: [6] The non-conductive rubber material comprises a rubber composition containing a non-carbon black reinforcing agent as a reinforcing agent.  The pneumatic tire according to claim 1, wherein: [7] The non-carbon black reinforcing agent is silica.  The pneumatic tire according to claim 6, wherein: