JP2010159017A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a low rolling resistance performance and high-speed durability, while securing the conductivity of a tire. <P>SOLUTION: A band layer 9 composed of a band-strip 12 rolled around in spiral has a belt layer 7 with a band extension section 9b being extended outward in the tire's axial direction. The outermost end part 7E of the belt layer 7 is covered with a U-letter edge cover rubber 13. The band layer 9 is equipped with a separation section K in which the rolling sections 12R of the band strips 12 stay apart at a distance of D which is equal to or more than 0.5 mm, in an overlapping area Q where it is overlapped with an outer strip section 13o of the edge cover rubber 13. The entry of a part of an under tread rubber 16 into the separation section K causes the under tread rubber 16 disposed inside and outside in the directions of the radius of the band layer 9 to come in contact with an edge cover rubber 13, thus a terminal part 17, the under tread rubber 16, the edge cover rubber 13 and a cushion rubber 14 are kept mutually electrically conductive. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire that suppresses accumulation of static electricity in a vehicle.

  In order to improve the fuel efficiency of automobiles and promote the reduction of exhaust gas, tires using silica as a reinforcing agent for tread rubber instead of carbon black have been proposed. This product maintains excellent wet grip performance on the low temperature side, so it exhibits excellent wet grip performance, while low hysteresis loss on the high temperature side reduces rolling resistance and wet grip performance. There is an advantage of both. On the other hand, since silica has high electrical insulation, it causes an increase in the electrical resistance of the tire and causes many electrical malfunctions such as causing radio wave interference due to accumulation of static electricity in the vehicle.

  Therefore, a thin under-tread rubber made of conductive rubber with a high carbon content is arranged on the inner side in the radial direction of the tread rubber made of an insulating rubber with a high silica content, and the tread rubber penetrates the tread rubber into the tread. A structure (so-called pen structure) in which a terminal portion extending to the ground surface is raised has been proposed (see, for example, Patent Document 1). In this structure, the static electricity of the vehicle passes from the rim to the undertread rubber through the outer layer rubber (that is, the clinch rubber and the side wall rubber), the belt layer, the band layer, etc. that forms the outer surface of the bead part and the side wall part. The terminal portion is discharged to the road surface.

JP 2000-16010 A

  In recent years, in order to further improve the low rolling resistance performance, in addition to the tread rubber, other rubber members having a relatively large deflection amount or a large rubber volume, for example, a cord layer such as a carcass, a belt layer, a band layer, etc. There is an increasing demand for applying silica to topping rubber, sidewall rubber, and the like. However, when the rubber member is formed of an insulating rubber containing high silica, the conventional conductive path from the rim to the undertread rubber is interrupted, and static electricity in the vehicle cannot be discharged.

  Therefore, as shown in FIG. 9 (A), the present inventor forms a cushion rubber c disposed between the outer end portion of the belt layer a and the carcass b with an insulating rubber, while the carcass b and the side wall. It has been proposed to newly provide a thin conductive rubber layer f extending from the cushion rubber c to the clinch rubber between the rubber d. In this case, since the under tread rubber g can be in direct contact with the cushion rubber c, a conductive path from the rim to the under tread rubber g can be formed via the clinch rubber, the conductive rubber layer f in the cushion rubber c, and the cushion rubber c.

  On the other hand, in the tire, in order to improve high-speed durability, as shown in FIG. 9B, the belt layer a and the band layer h are made wider, and in particular, the band layer h is made wider than the belt layer a. It is desired to restrain the tread portion with a wider width. However, when the wide belt layer a and the band layer h are employed in the tire having the structure proposed by the present inventor, it is difficult to ensure electrical contact between the undertread rubber g and the cushion rubber c. Become. Therefore, further studies are necessary to ensure conductivity.

  An object of the present invention is to provide a pneumatic tire that can ensure electrical conductivity even when a wide belt layer and a band layer are employed, and can improve low rolling resistance performance while improving high-speed durability. It is said.

In order to achieve the above object, the invention of claim 1 of the present application provides a carcass extending from the tread portion to the side wall portion to the bead core of the bead portion,
A belt layer disposed radially outside the carcass and inside the tread portion;
Cushion rubber having a triangular cross section interposed between the outer end of the belt layer and the carcass,
A band main portion that is arranged on the outer side in the radial direction of the belt layer and covers the belt layer, and a band extending portion that extends to the outer side in the tire axial direction of the belt layer and extends beyond the outer end in the tire axial direction. And a band layer in which a narrow strip-shaped band strip is continuously wound spirally,
A tread rubber which is arranged further radially outward of the band layer and forms a tread ground surface;
An under tread rubber that forms a sheet extending between the tread rubber and the band layer in the tire axial direction;
And including a terminal portion that penetrates the tread rubber inward and outward in the radial direction, the radially outer end portion is exposed to the tread ground surface, and the radially inner end portion contacts the undertread rubber,
A U-shaped edge cover rubber which has an outer piece portion covering a radially outer surface of the outer end portion and an inner piece portion covering a radially inner surface at the outer end portion of the belt layer and covers the outer end portion. Provided,
In addition, the topping rubber of the carcass, the topping rubber of the belt layer, the topping rubber of the band layer, and the tread rubber are formed of an insulating rubber material having a volume resistivity of 1 × 10 ⁸ Ωcm or more, and the terminal portion and the undertread The rubber, the edge cover rubber and the cushion rubber are formed of a conductive rubber material having a volume specific resistance of less than 1 × 10 ⁸ Ωcm,
The band layer includes a separation portion in which the wound portions of the band strip are separated from each other by an interval D of 0.5 mm or more in an overlapping region overlapped with the outer piece portion,
At the spacing portion, the under tread rubber and the edge cover rubber disposed inside and outside in the radial direction of the band layer are in contact with each other, and the terminal portion, the under tread rubber, the edge cover rubber, and the cushion rubber are electrically connected to each other. By conducting, a first conductive path from the tread ground surface to the cushion rubber is formed.

  The invention according to claim 2 is characterized in that the spaced-apart portion is formed in the circumferential direction by 0.5 rounds or more and 1 round or less.

  According to a third aspect of the present invention, the spacing portion is characterized in that the distance D is 10 mm or less.

According to a fourth aspect of the present invention, there is provided a sidewall rubber that is continuous with a tire axially outer end of the tread rubber and that forms an outer surface of the sidewall portion on the outer side in the tire axial direction of the carcass, and a radial direction of the sidewall rubber. A clinching rubber for preventing rim displacement that is connected to the inner end and forms the outer surface of the bead portion;
The sidewall rubber is formed of an insulating rubber material, and the clinch rubber is formed of a conductive rubber material,
By disposing a conductive rubber layer made of the conductive rubber material and having an upper end in contact with the cushion rubber and a lower end in contact with the clinch rubber between the sidewall rubber and the carcass, A second conductive path from the rubber to the outer surface of the bead portion is formed.

  The invention according to claim 5 is characterized in that 90% or more of the total mass of the rubber material used in the tire is made of an insulating rubber material.

  As described above, according to the present invention, an edge cover rubber made of a conductive rubber material is provided at the outer end of the belt layer, and the band layer is placed in an overlapping region where the band layer overlaps with the outer piece portion of the edge cover rubber. A separation portion is provided in which the winding portions of the strip are separated at an interval of 0.5 mm or more. As a result, a part of the undertread rubber can enter the space. Therefore, even when the topping rubber of the carcass, the belt layer and the band layer, and the tread rubber are formed of an insulating rubber material, and even when the belt layer and the band layer are widened, Under tread rubber and edge cover rubber can be brought into electrical contact, ensuring low tire resistance and high-speed durability while ensuring tire conductivity and preventing static electricity accumulation. .

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a pneumatic tire 1 of the present invention.

  In FIG. 1, a pneumatic tire 1 according to this embodiment includes a carcass 6 that extends from a tread portion 2 through a sidewall portion 3 to a bead core 5 of a bead portion 4, a radially outer side of the carcass 6, and an inside of the tread portion 2. A belt layer 7 disposed on the outer side in the radial direction of the belt layer 7, a tread rubber 2G disposed further on the outer side in the radial direction of the band layer 9 and forming the tread ground surface 2S, Side wall rubber 3G disposed on the outer side in the tire axial direction of the carcass 6 and forming the outer surface of the sidewall portion 3, and prevention of rim displacement disposed on the outer side in the tire axial direction of the carcass 6 and forming the outer surface of the bead portion 4 And a clinch rubber 4G for use. The sidewall rubber 3G continues to the outer end in the tire axial direction of the tread rubber 2G, and the clinch rubber 4G continues to the inner end in the radial direction of the sidewall rubber 3G.

  The carcass 6 is formed by one or more carcass plies 6A in this example, in which an array of carcass cords arranged at an angle of, for example, 70 to 90 ° with respect to the tire circumferential direction is covered with a topping rubber. . This carcass ply 6A is provided with a series of ply folded portions 6b folded around the bead core 5 from the inner side to the outer side in the tire axial direction on both sides of the toroidal ply main body portion 6a straddling the bead cores 5 and 5. Yeah. A bead apex rubber 8 is provided between the ply body portion 6a and the ply turn-up portion 6b so as to taper outward from the bead core 5 in the radial direction, and is reinforced from the bead portion 4 to the sidewall portion 3. ing.

  Next, the belt layer 7 includes two or more belt plies 7A, in this example, two belt plies 7A in which an array of belt cords arranged at an angle of, for example, 15 to 40 ° with respect to the tire circumferential direction is covered with topping rubber , 7B. The belt layer 7 enhances the belt rigidity by crossing the belt cords between the plies, and reinforces the tread portion 2 with a tagging effect. The radially inner belt ply 7A is, for example, about 7 to 15 mm wider than the outer belt ply 7B, thereby reducing the stress concentration at the ply end.

  Further, as shown in FIG. 2, the outer end portion 7E of the belt layer 7 is gradually separated from the carcass 6 toward the outer side in the tire axial direction, and a cushion rubber 14 having a triangular cross section is disposed in the separated portion Y. Is done. The cushion rubber 14 is made of a relatively soft rubber, and suppresses the cord end peeling starting from the belt cord end by relaxing the shear stress concentrated on the outer end portion 7E.

  The outer end portion 7E is further covered with a U-shaped edge cover rubber 13. The edge cover rubber 13 is formed by folding a thin rubber sheet having a thickness of about 0.1 to 2.0 mm into a U shape, and has an outer piece portion 13o covering the outer surface in the radial direction of the outer end portion 7E, and a radius. The outer end portion 7E is covered with an inner piece portion 13i that covers the inner surface in the direction. The edge cover rubber is conventionally used for covering and protecting the end portions of the carcass ply and the belt ply in heavy load tires and the like, and suppressing cord end peeling. However, the present invention is different from the conventional edge cover rubber in that it is used for forming a conductive path in the tire.

  Next, the band layer 9 is one or more formed by continuously winding a band strip 12 having a narrow band shape in a spiral shape as shown in FIG. A single band ply 9A is formed. As shown in FIG. 5, the band strip 12 is formed by covering a cord array 10 in which a plurality (n) of band cords 10 a are arranged in parallel with a topping rubber 11. If the strip width Ws of the band strip 12 is too wide, it becomes difficult to form the separating portion K in the overlapping region Q described later, and conversely, if the width is too narrow, the number of windings for forming the band ply increases and production is performed. Reduce sex. Accordingly, the strip width Ws is preferably about 5 to 15 mm, and the number n of the band cords 10a is preferably about 5 to 15.

  Further, as shown in FIG. 2, the band layer 9 is arranged on the outer side in the radial direction of the belt layer 7 so as to cover the belt layer 7, and is connected to the band main portion 9 a and is connected to the tire shaft of the belt layer 7. A band extending portion 9b extending beyond the outer end in the direction and extending outward in the tire axial direction is provided. By providing such a band extending portion 9b, the restraining force on the belt layer 7 can be sufficiently increased, and high-speed durability can be improved. This is because the belt cord is cut off at the outer end portion 7E of the belt layer 7 and easily moves. Therefore, when the band layer 9 has the same width as the belt layer 7 as in the prior art, the outer end portion 7E This is because the restraining force is insufficient and lifting on the tread shoulder side cannot be sufficiently suppressed. Accordingly, the band extending portion 9b is important from the viewpoint of high-speed durability, and the protruding width W1 in the tire axial direction from the outer end of the belt layer 7 of the band extending portion 9b is preferably 2 mm or more. Further, in this example, the width WB of the belt layer 7 itself is 105% or more of the width TW of the tread ground surface 2S, and is 5 to 15 mm wider than the conventional one. As a result, the high-speed durability is further improved.

  Further, the band layer 9 has an overlapping region Q that overlaps with the outer piece portion 13o of the edge cover rubber 13, and the adjacent winding portions 12R and 12R of the band strip 12 are located in the overlapping region Q. Is provided with a separation portion K that is separated by an interval D of 0.5 mm or more.

  Specifically, as shown in FIG. 4, the band layer 9 is formed by spirally winding the band strip 12 in the tire circumferential direction. At that time, at least in the overlapping region Q, adjacent band windings 9 are formed. By separating the turning parts 12R and 12R, a separation part K having a distance D of 0.5 mm or more is formed. In the remaining region other than the overlapping region Q, the separation portion K can be formed. However, from the viewpoint of the reinforcing effect by the band layer 9, it is preferable not to form the separation portion K in the remaining region. As an example in which this separation portion K is not formed, as in this example, close winding for abutting the side edges of the winding portion 12R, overlapping winding for overlapping the side edges, and 0.5 mm between the side edges. A gap winding providing a smaller interval can be appropriately employed. As a winding method of the band strip 12, in this example, the parallel winding portion Ra substantially parallel to the tire circumferential direction and the inclined winding portion Rb that is inclined are alternately repeated. This inclined winding portion Rb It is preferable to form the spacing portion K by using the above in order to stably form the distance D.

  Next, the tread rubber 2 </ b> G, the under tread rubber 16, and the terminal portion 17 are disposed outside the band layer 9 in the radial direction.

  As the tread rubber 2G, in this example, a cap rubber portion 2G1 that forms the tread contact surface 2S, a base rubber portion 2G2 on the radially inner side thereof, and sidewall rubber 3G disposed on both outer sides in the tire axial direction, The thing of the four-layer structure which consists of the wing rubber part 2G3 of the cross-sectional triangle shape which improves adhesiveness of this is illustrated. However, other conventional structures such as a three-layer structure excluding the base rubber portion 2G2 can be employed.

  The under-tread rubber 16 is a rubber that enhances the adhesion to the tread rubber 2G, and has a thickness of 0.1 to 2 mm extending between the tread rubber 2G and the band layer 9 in the tire axial direction. Form a thin sheet of about 0mm. In this example, the undertread rubber 16 is formed over the entire width between the wing rubber portions 2G3 and 2G3.

  The terminal portion 17 extends through the tread rubber 2G inward and outward in the radial direction, and the outer end portion in the radial direction is exposed to the tread ground surface 2S and the inner end portion in the radial direction is connected to the undertread rubber 16. is doing. Although this terminal part 17 has illustrated the case of the rib-like body extended in the tire circumferential direction in this example, you may make it distribute in the tread part 2 as a columnar body.

In the tire 1 of this embodiment, in order to improve the low rolling resistance performance, the topping rubber of the carcass 6, the topping rubber of the belt layer 7, the topping rubber of the band layer 9, the tread rubber 2G, and the sidewall The rubber 3G is formed of an insulating rubber material having a volume specific resistance of 1 × 10 ⁸ Ωcm or more, respectively, while the terminal portion 17, the under tread rubber 16, the edge cover rubber 13, The cushion rubber 14 and the clinch rubber 4G are each formed of a conductive rubber material having a volume specific resistance of less than 1 × 10 ⁸ Ωcm.

  Here, in the tire 1, since the band layer 9 has the band extending portion 9b, the direct contact between the undertread rubber 16 and the cushion rubber 14 is cut off as shown in FIG. However, the band layer 9 has the separation portion K. Therefore, a part of the under tread rubber 16 enters the spacing portion K and can contact the edge cover rubber 13 at the outer piece portion 13o. The edge cover rubber 13 can contact the cushion rubber 14 at the inner piece portion 13i. That is, the terminal portion 17, the under tread rubber 16, the edge cover rubber 13 and the cushion rubber 14 can be electrically conducted through the separation portion K, and thereby the first conductivity from the tread ground surface 2S to the cushion rubber. A road can be formed.

  If the distance D in the spacing portion K is less than 0.5 mm, the electrical continuity between the undertread rubber 16 and the edge cover rubber 13 is insufficient and uncertain. Accordingly, the distance D is 0.5 mm or more, preferably 1.0 mm or more, and more preferably 2.0 mm or more. If the distance D is too large, the reinforcing effect is reduced, so the upper limit is preferably 10 mm or less, more preferably 5 mm or less. For the same reason, the spacing portion K is preferably formed in the circumferential direction by 0.5 or more, more preferably 0.7 or more, and the upper limit thereof is preferably 1.0 or less. In order to form the separation portion K, the width Wq of the overlapping region Q is 1.0 times or more, preferably 2.0 times or more of the strip width Ws.

  In this example, a conductive rubber layer 21 is formed between the sidewall rubber 3G and the carcass 6 so that the upper end portion is in contact with the cushion rubber 14 and the lower end portion is in contact with the clinch rubber 4G. The conductive rubber layer 21 has a thin sheet shape with a thickness of about 0.1 to 2.0 mm, and is made of the conductive rubber material so as to reach the outer surface of the bead portion 4 from the cushion rubber 14. A second conductive path may be formed.

  Thus, even when the pneumatic tire 1 is provided with the band extending portion 9b in the band layer 9, the terminal portion 17, the under tread rubber 16, the edge cover rubber 13, the cushion rubber 14, the clinch rubber 4G, Even when all the rubber materials other than the conductive rubber layer 21 are formed of an insulating rubber material, the first and second conductive paths from the tread ground surface 2S to the rim R can be formed, and the low rolling resistance performance can be formed. In addition, accumulation of static electricity can be prevented while improving high-speed durability.

  It is also possible to increase the usage rate of the insulating rubber material to 90% or more of the total mass of the rubber material used in the tire, and further improvement in rolling resistance performance can be expected. This also greatly reduces the use of carbon black made up of limited petroleum resources, which can reduce dependence on petroleum resources and can greatly contribute to the promotion of eco-friendly tires.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  A pneumatic tire (size 195 / 65R15) having the basic structure of FIG. 1 was prototyped, and the high speed durability and electrical resistance of each test tire were measured. The results are shown in Table 1. In addition, the structure of the tread edge of the comparative example 1 and the comparative example 2 is shown in FIGS. The specifications are substantially the same except for the specifications listed in the table.

Only the terminal rubber, the under tread rubber, the edge cover rubber, the cushion rubber, the clinch rubber, and the inner conductive rubber layer are made of a conductive rubber material having a volume resistivity of less than 1.0 × 10 ⁵ Ωcm. An insulating rubber material having a volume resistivity of 1.0 × 10 ⁸ Ωcm or more was used.

  The strip width Ws of the band strip was 10.0 mm, and the width Wq of the overlapping region Q by the edge cover rubber was 25.0 mm.

<Electric resistance of tire>
As shown in FIG. 7, the insulating plate 51 (electric resistance 10 ¹² or more) plate metal installation surface on the polished 52 (electric resistance 10Ω or less), the tire rim assembly Using a measuring device including a conductive tire mounting shaft 53 to be held and an electrical resistance measuring instrument 54, the electrical resistance value of the tire and rim assembly was measured in accordance with JATMA regulations. Each of the test tires was a tire in which the surface release agent and dirt were sufficiently removed in advance and were sufficiently dried. Other conditions are as follows.
Rim: Aluminum alloy 15 × 6JJ
Internal pressure: 200 kPa
Load: 5.3kN
Test environment temperature (test room temperature): 25 ° C
Humidity: 50%
Measuring range of electric resistance measuring device: 10 ^{3 to} 1.6 × 10 ¹⁶ Ω
Test voltage (applied voltage): 1000V

The test procedure is as follows.
(1) Mount the test tire on the rim and prepare a tire / rim assembly. At this time, soapy water is used as a lubricant at the contact portion between the two.
(2) The tire / rim assembly is allowed to stand in the test room for 2 hours and then attached to the tire mounting shaft 52.
(3) The tire / rim assembly is loaded with the load for 0.5 minutes, and further for 0.5 minutes after being released and for 2 minutes after being released.
(4) When the test voltage is applied and 5 minutes have passed, the electrical resistance value between the tire mounting shaft 53 and the metal plate 52 is measured by the electrical resistance measuring instrument 54. The measurement is performed at four positions at 90 ° intervals in the tire circumferential direction, and the maximum value among them is taken as the electrical resistance value (measured value) of the tire.

<High speed durability>
In accordance with the ECE30 standard, a sample tire is tested at a speed of 170 km / h to 10 km / h-20 minutes under a rim (15 × 6JJ), internal pressure (280 kPa), and load (5.0 KN) using a drum testing machine. Step up the speed and drive until the tire breaks. Then, the speed and time (minute) when the tire was damaged were measured.

It is sectional drawing which shows one Example of the pneumatic tire of this invention. It is sectional drawing which expands and shows the tread part. It is sectional drawing which expands and shows the principal part further. It is an expanded view which shows the winding state of a band strip. It is a perspective view which shows a band strip. It is sectional drawing which shows a bead part with the inside conductive rubber layer. 1 is a schematic cross-sectional view conceptually showing a tire electrical resistance measuring device. It is a fragmentary sectional view of the tread part which shows the structure of comparative examples 1 and 2 of Table 1. (A), (B) is a fragmentary sectional view of the tread part explaining background art.

2 tread portion 2S tread contact surface 2G tread rubber 3 side wall portion 3G side wall rubber 4 bead portion 4G clinch rubber 5 bead core 6 carcass 7 belt layer 7E outer end portion 9 band layer 9a band main portion 9b band extending portion 12 band strip 13 Edge cover rubber 13i Inner piece portion 13o Outer piece portion 14 Cushion rubber 16 Under tread rubber 17 Terminal portion 20 Conductive rubber layer 22 in first conductive path 21 Second conductive path K Spacing portion Q Overlapping region

Claims (5)

A carcass that extends from the tread part to the bead core of the bead part through the sidewall part,
A belt layer disposed radially outside the carcass and inside the tread portion;
Cushion rubber having a triangular cross section interposed between the outer end of the belt layer and the carcass,
A band main portion that is arranged on the outer side in the radial direction of the belt layer and covers the belt layer, and a band extending portion that extends to the outer side in the tire axial direction of the belt layer and extends beyond the outer end in the tire axial direction. And a band layer in which a narrow strip-shaped band strip is continuously wound spirally,
A tread rubber which is arranged further radially outward of the band layer and forms a tread ground surface;
An under tread rubber that forms a sheet extending between the tread rubber and the band layer in the tire axial direction;
And including a terminal portion that penetrates the tread rubber inward and outward in the radial direction, the radially outer end portion is exposed to the tread ground surface, and the radially inner end portion contacts the undertread rubber,
A U-shaped edge cover rubber which has an outer piece portion covering an outer surface in the radial direction of the outer end portion and an inner piece portion covering an inner surface in the radial direction at the outer end portion of the belt layer and covers the outer end portion. Provided,
In addition, the topping rubber of the carcass, the topping rubber of the belt layer, the topping rubber of the band layer, and the tread rubber are formed of an insulating rubber material having a volume resistivity of 1 × 10 ⁸ Ωcm or more, and the terminal portion and the undertread The rubber, the edge cover rubber and the cushion rubber are formed of a conductive rubber material having a volume specific resistance of less than 1 × 10 ⁸ Ωcm,
The band layer includes a separation portion in which the wound portions of the band strip are separated from each other by an interval D of 0.5 mm or more in an overlapping region overlapping the outer piece portion,
At the spacing portion, the under tread rubber and the edge cover rubber disposed inside and outside in the radial direction of the band layer are in contact with each other, and the terminal portion, the under tread rubber, the edge cover rubber, and the cushion rubber are electrically connected to each other. A pneumatic tire characterized by forming a first conductive path from the tread contact surface to the cushion rubber by conducting.   2. The pneumatic tire according to claim 1, wherein the spacing portion is formed in the circumferential direction by 0.5 to 1 round.   The pneumatic tire according to claim 1 or 2, wherein the spacing portion has a distance D of 10 mm or less. A sidewall rubber that is continuous with a tire axial direction outer end of the tread rubber and that forms an outer surface of the sidewall portion, and a bead portion that is continuous with a radially inner end of the sidewall rubber, on the outer side in the tire axial direction of the carcass. With clinching rubber for preventing rim displacement that forms the outer side of
The sidewall rubber is formed of an insulating rubber material, and the clinch rubber is formed of a conductive rubber material,
By disposing a conductive rubber layer made of the conductive rubber material and having an upper end in contact with the cushion rubber and a lower end in contact with the clinch rubber between the sidewall rubber and the carcass, The pneumatic tire according to any one of claims 1 to 3, wherein a second conductive path extending from rubber to the outer surface of the bead portion is formed.   The pneumatic tire according to any one of claims 1 to 4, wherein 90% or more of the total mass of the rubber material used for the tire is made of an insulating rubber material.

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