JP5608587B2 - Pneumatic tire manufacturing method and pneumatic tire - Google Patents

Description

  The present invention relates to a method for manufacturing a pneumatic tire capable of discharging static electricity generated in a vehicle body or a tire to a road surface, and the pneumatic tire.

  In recent years, pneumatic tires in which tread rubber is highly compounded with silica have been proposed for the purpose of reducing rolling resistance of tires that are closely related to fuel efficiency. However, such tread rubber has a higher electrical resistance than those with a high carbon black content and inhibits the release of static electricity generated in the vehicle body and tires to the road surface, so that problems such as radio noise are likely to occur. there were.

  Therefore, a pneumatic tire has been developed in which a conductive portion made of a conductive rubber compounded with carbon black or the like is provided on a tread rubber made of non-conductive rubber compounded with silica or the like so as to exhibit a current-carrying performance. .

  For example, in the pneumatic tires described in Patent Documents 1 and 2 below, from a conductive rubber that penetrates the tread rubber in the tire radial direction, the outer end portion is exposed to the tread grounding surface, and the inner end portion is connected to the under tread. A terminal portion is provided. Further, in these pneumatic tires, a conductive band or a conductive rubber whose upper end portion is in contact with the cushion rubber between the outer end portion of the belt layer and the carcass and whose other end portion is in contact with the clinch rubber forming the outer surface of the bead portion. By providing the layer between the carcass and the sidewall rubber, a conductive path for discharging static electricity is formed together with the terminal portion, the undertread, and the clinch rubber.

  However, the conductive band or the conductive rubber layer as described above is partially provided in the tire circumferential direction, which may lead to deterioration of uniformity. Also, in the manufacture of so-called side-on-tread type pneumatic tires with side wall rubber ends placed on both sides of the tread rubber, the vicinity of the side surface of the tread rubber becomes a step, which tends to cause air accumulation, resulting in poor process. It is known that it is necessary to take measures against it.

JP 2009-154608 A JP 2010-159017 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a pneumatic tire that can reduce energies while ensuring a current-carrying performance and that has few process defects. It is to provide.

  The above object can be achieved by the present invention as described below. That is, in the method for manufacturing a pneumatic tire according to the present invention, the tread rubber formed of non-conductive rubber is electrically conductive made of conductive rubber having one end exposed on the ground surface and the other end reaching the side surface of the tread rubber. A method of manufacturing a pneumatic tire in which an end portion of a sidewall rubber is placed on both side surfaces of the tread rubber, wherein a rubber ribbon made of non-conductive rubber is connected to the inner side in the tire radial direction from the side surface of the tread rubber. In the region extending to the tire, the side wall rubber is formed by spirally winding along the tire circumferential direction, and at least in the region in contact with the side surface of the tread rubber, the surface facing the carcass is covered with the conductive rubber portion The conductive rubber portion is connected to the conductive rubber portion adjacent to the inner side in the tire radial direction, or is formed of a conductive rubber provided on the carcass. Characterized in that it connects to.

  The conductive rubber portion is connected to the other end of the conductive portion reaching the side surface of the tread rubber, and is connected to the conductive rubber portion adjacent to the inner side in the tire radial direction or made of conductive rubber provided on the carcass. Connected to the sheet. Therefore, according to this configuration, a conductive path extending from the side surface of the tread rubber to the inside in the tire radial direction is formed on the carcass by the conductive rubber portion, and the topping rubber and the sidewall rubber of the carcass ply are formed of the nonconductive rubber. Even in such a case, the energization performance can be secured. The side wall rubber is formed by wrapping a rubber ribbon made of non-conductive rubber, and a conductive member is provided separately in order to cover a part of the rubber ribbon with a conductive rubber portion to ensure current-carrying performance. There is no need for it, and the decline in uniformity can be suppressed. Furthermore, since the rubber ribbon is wound around the region extending inward in the tire radial direction from the side surface of the tread rubber, a step near the side surface of the tread rubber can be filled, and process defects due to air accumulation can be effectively prevented.

  In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that the conductive rubber portion is disposed in an area of 1/5 or more and less than 1 of the entire circumference of the tire.

  By placing the conductive rubber part in the area of 1/5 or more of the entire circumference of the tire, stable energization performance can be secured, and by placing it in the area of less than 1 round, the volume of the conductive rubber is suppressed. Thus, rolling resistance can be reduced.

  The pneumatic tire according to the present invention embeds a conductive portion made of conductive rubber, one end of which is exposed to the ground surface and the other end reaches the side surface of the tread rubber. A pneumatic tire in which end portions of sidewall rubber are placed on both side surfaces of the tread rubber, wherein the sidewall rubber extends a rubber ribbon made of non-conductive rubber from the side surface of the tread rubber inward in the tire radial direction. The rubber ribbon is formed by being spirally wound around the tire in the tire circumferential direction, and at least in the area in contact with the side surface of the tread rubber, the surface facing the carcass is covered with the conductive rubber portion, and the conductive rubber The portion is connected to a conductive sheet that is connected to a conductive rubber portion adjacent to the inner side in the tire radial direction or made of conductive rubber provided on a carcass. It is intended to.

  According to this configuration, the conductive rubber portion forms a conductive path on the carcass extending from the side surface of the tread rubber to the inner side in the tire radial direction, so the topping rubber and sidewall rubber of the carcass ply are formed of nonconductive rubber. Even in such a case, the energization performance can be secured. In addition, since a part of the rubber ribbon for molding the sidewall rubber is covered with the conductive rubber portion to ensure the current-carrying performance, it is not necessary to provide a separate conductive member, and a reduction in uniformity can be suppressed. Furthermore, since the rubber ribbon is wound around the region extending inward in the tire radial direction from the side surface of the tread rubber, a step near the side surface of the tread rubber can be filled, and process defects due to air accumulation can be effectively prevented.

Tire meridian cross-sectional view showing an example of a pneumatic tire according to the present invention Schematic configuration diagram showing equipment for forming and winding rubber ribbons Sectional view showing an example of a rubber ribbon used for molding sidewall rubber Cross-sectional view schematically showing the sidewall molding process Front view showing the arrangement of conductive rubber parts Tire meridian cross-sectional view showing a pneumatic tire according to another embodiment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A pneumatic tire T shown in FIG. 1 includes a pair of bead portions 1, sidewall portions 2 extending outward in the tire radial direction from each of the bead portions 1, and tire radial direction outer ends of the sidewall portions 2. And a tread portion 3 that is connected to the tread. The bead portion 1 is provided with an annular bead 1a formed by covering a converging body such as a steel wire with rubber and a bead filler 1b made of hard rubber.

  A toroid-like carcass layer 7 (corresponding to the carcass of the present application) is disposed between the pair of bead portions 1, and the ends thereof are locked in a state of being wound up via the beads 1 a. The carcass layer 7 is composed of at least one carcass ply (in this embodiment, two), and the carcass ply is formed by covering a cord extending at an angle of approximately 90 ° with respect to the tire equator C with a topping rubber. Has been. An inner liner rubber 5 for maintaining air pressure is disposed on the inner periphery of the carcass layer 7.

  A rim strip rubber 4 in contact with a rim (not shown) is disposed on the outer periphery of the bead portion 1 of the carcass layer 7.

  The tread portion 3 is provided with a tread rubber 10 made of non-conductive rubber. The tread rubber 10 has a conductive rubber made of a conductive rubber having one end exposed on the ground surface and the other end reaching the side surface of the tread rubber 10. The part 13 is embedded. In the present embodiment, the other end of the conductive portion 13 reaches the side surface through the bottom surface of the tread rubber 10, but may be configured to reach the side surface directly without passing through the bottom surface of the tread rubber 10. The tread rubber 10 of the present embodiment includes a cap portion 12 formed of non-conductive rubber and constituting a ground plane, and a base portion 11 formed of non-conductive rubber and joined to the inside of the cap portion 12 in the tire radial direction. With.

  A sidewall rubber 9 is disposed on the outer periphery of the sidewall portion 2 of the carcass layer 7. The tire T employs a so-called side-on-tread structure in which end portions of the sidewall rubber 9 are placed on both side surfaces 10 a of the tread rubber 10.

  As will be described in detail later, the side wall rubber 9 is formed of a non-conductive rubber rubber ribbon (not shown in FIG. 1) along the tire circumferential direction in a region extending inwardly in the tire radial direction from the side surface 10 a of the tread rubber 10. It is formed by winding it in a spiral. However, in the rubber ribbon, at least in a region in contact with the side surface 10a of the tread rubber 10, the surface facing the carcass layer 7 is covered with the conductive rubber portion 22, and a part of the conductive rubber portion 22 in the ribbon width direction is covered. The conductive portion 13 exposed on the side surface 10a of the tread rubber 10 is connected. In addition, the conductive rubber portion 22 is spirally wound so as to be connected to the adjacent conductive rubber portion 22 on the inner side in the tire radial direction, and continuously extends from the side surface 10a of the tread rubber 10 toward the inner side in the tire radial direction. In particular, it is connected to the rim strip rubber 4.

  On the outer periphery of the tread portion 3 of the carcass layer 7, a belt layer 6 composed of a plurality of (two in this embodiment) belt plies is disposed. Each belt ply is formed by covering a cord extending obliquely with respect to the tire equator C with a topping rubber, and the cords are laminated so that the cords cross each other in opposite directions. On the outer periphery of the belt layer 6, a belt reinforcing layer formed by covering a cord extending substantially in the tire circumferential direction with a topping rubber may be disposed.

Here, the conductive rubber refers to rubber having a volume resistivity of less than 10 ⁸ Ω · cm. For example, the conductive rubber is produced by blending carbon black as a reinforcing agent in a high ratio with raw material rubber. In addition to carbon black, carbon fibers such as carbon fiber and graphite, and metal-based known conductivity imparting materials such as metal powders, metal oxides, metal flakes, and metal fibers can also be blended. Non-conductive rubber refers to rubber having a volume resistivity of 10 ⁸ Ω · cm or more, and is produced, for example, by blending silica as a reinforcing agent in a high ratio with raw material rubber.

  Examples of the raw rubber include natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), and butyl rubber (IIR). These may be used alone or in combination of two or more. Used. A vulcanizing agent, a vulcanization accelerator, a plasticizer, an anti-aging agent and the like are appropriately blended with the raw rubber.

The conductive rubber has a nitrogen adsorption specific surface area: N ₂ SA (m ² / g) × carbon black content (mass%) of 1900 or more, preferably 2000 or more, and dibutyl phthalate oil absorption: DBP ( ml / 100 g) × carbon black content (mass%) of 1500 or more, preferably 1700 or more. N ₂ SA is determined according to ASTM D3037-89, and DBP is determined according to ASTM D2414-90.

  In the tire T, since both the base portion 11 and the cap portion 12 are made of non-conductive rubber, the improvement effect by forming the tread rubber 10 with non-conductive rubber (in the case of high silica content) The effect of reducing rolling resistance and the effect of improving braking performance on wet road surfaces can be improved satisfactorily.

  The grounding surface from which the conductive portion 13 is exposed is assembled with a rim on a regular rim, and the tire is placed vertically on a flat road surface filled with a regular internal pressure, and the surface of the tread portion that contacts the road surface when a regular load is applied. Point to. The regular rim is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, a standard rim for JATMA, “Design Rim” for TRA, and “Measuring for ETRTO”. Rim ".

  The normal internal pressure is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. “INFLATION PRESSURE” for the maximum value described in “ETRTO”, but 180 KPa when the tire is for a passenger car. In addition, the normal load is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. If it is JATMA, it is the maximum load capacity, and if it is TRA, the maximum load described in the above table. If the value is ETRTO, it is “LOAD CAPACITY”, but if the tire is for a passenger car, the load is 85% of the corresponding load at an internal pressure of 180 KPa.

  The conductive portion 13 extends from the ground contact surface inward in the tire radial direction and reaches the outer peripheral surface of the base portion 11. The conductive portion 13 is provided continuously to the first conductive portion 13 a and extends in the tire width direction (this embodiment). In the embodiment, the second conductive portion 13b extends in the right direction in FIG. 1 and reaches the side surface through the bottom surface of the tread rubber 10. In the present embodiment, the first conductive portion 13a is inclined in the vicinity of the tire equator C and exposed to the ground surface, and its tip portion is extended in the tire width direction to ensure the exposure frequency on the ground surface. To increase the degree of freedom of pattern design.

  In the pneumatic tire T of the present embodiment, static electricity generated in the vehicle body and the tire is discharged to the road surface through a conductive path through the rim, the rim strip rubber 4, the conductive rubber portion 22, and the conductive portion 13. Therefore, the rim strip rubber 4 is made of conductive rubber. The topping rubber of the carcass ply can be formed of conductive rubber or non-conductive rubber, but is preferably formed of non-conductive rubber from the viewpoint of reducing rolling resistance. Further, the topping rubber of the belt layer 6 or the belt reinforcing layer can be formed of non-conductive rubber.

  Next, an example of a method for manufacturing the pneumatic tire T will be described. Since this pneumatic tire T can be manufactured in the same manner as the normal tire manufacturing process except for the point relating to the sidewall rubber 9 described below, the description will focus on the molding process of the sidewall rubber 9.

  The sidewall rubber 9 is formed by winding a rubber ribbon made of non-conductive rubber in a spiral shape along the tire circumferential direction in a region extending inwardly in the tire radial direction from the side surface 10a of the tread rubber 10. However, at least in a region in contact with the side surface 10a of the tread rubber 10, the rubber ribbon has a structure in which a surface facing the carcass layer 7 is covered with a conductive rubber portion, that is, a multilayer structure.

  The molding and winding of the rubber ribbon can be performed using equipment as illustrated in FIG. This equipment includes a rubber ribbon supply device 30 capable of co-extruding two types of rubber to form a multilayer rubber ribbon 20, a rotary support 31 around which the rubber ribbon 20 supplied from the rubber ribbon supply device 30 is wound, and a rubber ribbon supply device 30. And a control device 32 that controls the operation of the rotary support 31. The rotary support 31 is configured to be capable of rotating in the R direction around the shaft 31a and moving in the axial direction.

  The extruder 33 includes a hopper 33a, a screw 33b, a barrel 33c, a drive device 33d for the screw 33b, and a head portion 33e incorporating a gear pump. Similarly, the extruder 34 includes a hopper 34a, a screw 34b, a barrel 34c, a driving device 34d, and a head portion 34e. At the front ends of the pair of extruders 33 and 34, a rubber unit 35 to which a base 36 is attached is provided.

  When non-conductive rubber, which is a rubber material, is put into the hopper 33a and conductive rubber, which is a rubber material, is put into the hopper 34a, each rubber is fed forward while being kneaded by the screws 33b and 34b, and the head portions 33e and 34e. Then, they are united in a predetermined shape at the rubber uniting part 35 and extruded from the discharge port 36a as a multi-layer rubber ribbon 20. The molded rubber ribbon 20 is fed forward by a roll 37 and wound around the rotary support 31 while being pressed by a roller 38.

  FIG. 3 (A) shows a multilayer rubber ribbon 20 in which a rubber ribbon 20 made of non-conductive rubber 21 is covered with a conductive rubber portion 22 made of conductive rubber. The lower side is a surface facing the carcass layer 7. The cross section of the rubber ribbon 20 is not limited to a trapezoidal shape as shown in the figure, and may be other shapes such as a triangular shape.

  Further, when the rubber ribbon 20 is extruded, the rotation of the gear pump in the head portion 34e is stopped, and if necessary, the rotation of the screw 34b is also stopped to stop the extrusion of the conductive rubber. A single layer rubber ribbon 20 formed only of the non-conductive rubber 21 is obtained. The operation of the gear pumps and the screws 33b and 34b in the head portions 33e and 34e is controlled by the control device 32, so that the single layer and the multiple layers in the rubber ribbon 20 can be switched.

  The sidewall rubber 9 is formed by winding the rubber ribbon 20 around the rotary support 31 in a spiral shape along the tire circumferential direction. Other tire components such as the carcass layer 7, the tread rubber 10, and the rim strip rubber 4 are set in advance on the rotary support 31 and are formed into a toroidal shape. FIG. 4 is a cross-sectional view schematically showing the molding process of the sidewall rubber 9. In addition, after molding the sidewall rubber 9 on the rotary support 31, the tread rubber 10 may be attached to a predetermined position so that the conductive portion 13 and the conductive rubber portion 22 of the tread rubber 10 are connected.

  The rubber ribbon 20 is wound so that a part of the conductive rubber portion 22 in the ribbon width direction is in contact with the side surface 10a of the tread rubber 10 as shown in FIG. Thereby, the conductive rubber portion 22 is connected to the conductive portion 13 exposed on the side surface 10 a of the tread rubber 10. In FIG. 4, the conductive rubber portion 22 is colored so that it can be distinguished from the nonconductive rubber 21.

  As shown in FIG. 4A, the rubber ribbon 20 is spirally wound so that the rubber ribbons 20 adjacent to each other in the ribbon width direction overlap with each other with an overlap margin 20a. As the rubber ribbon 20 is wound, the conductive rubber portion 22 is spirally wound so as to be connected to the conductive rubber portion 22 adjacent to the inner side in the tire radial direction. In this manner, the conductive rubber portion 22 continuously extends from the side surface 10a of the tread rubber 10 toward the inside in the tire radial direction, and is finally connected to the rim strip rubber 4.

  Next, as shown in FIG. 4B, the side wall rubber 9 having a desired cross-sectional shape is obtained by continuously winding the rubber ribbon 20 in a spiral shape on the upper surface of the wound body of the wound rubber ribbon 20. Will be molded. At this time, the rubber ribbon 20 may have a single-layer structure formed of only the non-conductive rubber 21 as shown in FIG.

  Further, as shown in FIG. 5, the conductive rubber portion 22 is preferably arranged in a region of 1/5 or more and less than 1 of the entire tire circumference. Stable energization performance can be ensured by arranging in the area of 1/5 or more rounds, and the volume of the conductive rubber can be suppressed and rolling resistance can be reduced by arranging in the area of less than 1 round. Further, it is more preferable that the conductive rubber portion 22 is disposed in a region of less than ½ of the entire tire circumference so that the volume of the conductive rubber can be further suppressed. In order to arrange the conductive rubber portion 22 in this way, in the winding process of the rubber ribbon 20, a multilayer rubber ribbon 20 covered with the conductive rubber portion 22 is used in a predetermined region, and non-conductive in other regions. A single-layer rubber ribbon 20 formed only from the rubber 21 may be used.

  The width 22W of the conductive rubber portion 22 is preferably 30 to 70% of the total width 20W of the rubber ribbon 20, and more preferably 35 to 55%. When this ratio is 30% or more, the width of the conductive rubber portion 22 can be secured to maintain the current-carrying performance, and problems such as rubber burning do not occur in the manufacturing process. Moreover, when this ratio is 70% or less, the volume of the conductive rubber can be reduced satisfactorily.

  The thickness 20T of the rubber ribbon 20 is preferably 1.0 to 4.0 mm, and more preferably 1.5 to 3.0 mm. The thickness 22T of the conductive rubber portion 22 is preferably 0.2 to 0.8 mm, and more preferably 0.3 to 0.5 mm. When the thickness 22T of the conductive rubber portion 22 is 0.2 mm or more, stable energization performance can be secured, and when the thickness is 0.8 mm or less, the volume of the conductive rubber can be favorably reduced.

  The tire T manufactured in this way is vulcanized in the vulcanization molding process, and a tread pattern is provided on the surface of the tread rubber 10.

[Another embodiment]
In the above-described embodiment, an example in which the conductive rubber portion 22 is connected to the conductive rubber portion 22 adjacent to the inner side in the tire radial direction by winding the multilayer rubber ribbon 20 spirally along the tire circumferential direction has been shown. However, the multi-layer rubber ribbon 20 may be wound only once. The rubber ribbon 20 following the multilayer rubber ribbon 20 may have a single layer structure as shown in FIG. In this case, as shown in FIG. 6, the rubber ribbon 20 is wound so that a part of the conductive rubber portion 22 in the ribbon width direction is connected to a conductive sheet 70 made of conductive rubber provided on the carcass layer 7. The conductive sheet 70 is connected to the rim strip rubber 4 and constitutes a conductive path. Furthermore, a plurality of layers of the rubber ribbon 20 may be wound in a spiral manner so that the conductive rubber portion 22 is connected to the conductive sheet 70.

  Examples that specifically show the structure and effects of the present invention will be described below. The size of the tire used for the evaluation is 245 / 55R19, and the tire structure and the rubber composition in each example are common except for the structure of the conductive portion described below.

The evaluation items are as follows.
Current-carrying performance: The presence or absence of current-carrying performance was evaluated based on the presence or absence of a conductive path.
Uniformity: Based on the test method specified in JIS D4233, RFV (radial force variation) was measured to evaluate tire uniformity. Specifically, the tire was pressed against the rotating drum so that a predetermined load was applied, and the amount of variation in the reaction force in the radial direction that occurred when the tire was rotated while keeping the distance between both axes constant was measured. Index evaluation is performed by setting the reciprocal of the fluctuation amount of Comparative Example 1 to 100, and the larger the value, the better the uniformity.
Process failure: Evaluation was performed with the number excluding the number in which the number of evaluations was 100, and the number of occurrences of defects such as air stagnation and rubber scorch with sidewall rubber. The closer the number is to 100, the fewer process defects.
Rolling resistance: The rolling resistance was measured with a rolling resistance tester. The index evaluation is performed with the result of Comparative Example 1 being 100, and the smaller the value, the smaller the rolling resistance.

  In the tire having the structure shown in FIG. 6, the conductive rubber portion is disposed in the region of 1/3 of the entire circumference of the tire in Example 1, and in the region of 1 round, Example 2 and 1/8. Example 3 was arranged in the peripheral region. The conductive rubber portion is connected to the conductive sheet by winding a plurality of layers of rubber ribbons around the periphery. Moreover, the same thing as Example 1 was set as the comparative example 1 except shape | molding sidewall rubber | gum only using the rubber ribbon which consists of nonelectroconductive rubber | gum. Comparative Example 2 was the same as Comparative Example 1 except that the conductive sheet provided on the carcass layer extended to the bottom surface of the tread rubber. The evaluation results are shown in Table 1.

  As shown in Table 1, in Comparative Example 1, since the side wall rubber does not include the conductive rubber portion, the energization performance is not exhibited. In Comparative Example 2, the conductive sheet provided on the carcass layer extends to the bottom surface of the tread rubber, so that the current-carrying performance can be exhibited by the conductive portion and the conductive sheet, but the steps near both side surfaces of the tread rubber are not eliminated. There is an air pocket.

  In Examples 1 and 2, the current-carrying performance is exhibited, the uniformity is not deteriorated, and no process failure occurs. In Example 3, although the current-carrying performance is exhibited, it is unstable, and a process failure of the rubber burning also occurs.

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Tread part 4 Rim strip rubber 6 Belt layer 7 Carcass layer 8 Side wall rubber 10 Tread rubber 10a Side surface of tread rubber 13 Conductive part 20 Rubber ribbon 20a Overlap 21 Nonconductive rubber 22 Conductive rubber part 70 conductive sheet T pneumatic tire

Claims (5)

A tread rubber made of non-conductive rubber has a conductive portion made of conductive rubber with one end exposed on the ground surface and the other end reaching the side surface of the tread rubber, and side walls on both sides of the tread rubber. A method of manufacturing a pneumatic tire with rubber ends mounted thereon,
A step of forming a sidewall rubber by winding a rubber ribbon made of non-conductive rubber in a spiral shape along the tire circumferential direction in a region extending inward in the tire radial direction from the side surface of the tread rubber ;
The rubber ribbon has a structure in which a surface facing the carcass is covered with a conductive rubber part,
The conductive rubber portions that are adjacent to each other in the tire radial direction as a result of connecting the conductive rubber portions to the conductive portions exposed on the side surfaces of the tread rubber and spirally winding the rubber ribbon. A manufacturing method of a pneumatic tire characterized by connecting. A tread rubber made of non-conductive rubber has a conductive portion made of conductive rubber with one end exposed on the ground surface and the other end reaching the side surface of the tread rubber, and side walls on both sides of the tread rubber. A method of manufacturing a pneumatic tire with rubber ends mounted thereon,
  A step of forming a sidewall rubber by winding a rubber ribbon made of non-conductive rubber in a spiral shape along the tire circumferential direction in a region extending inward in the tire radial direction from the side surface of the tread rubber;
  At least in a region in contact with the side surface of the tread rubber, the rubber ribbon has a structure in which a surface facing the carcass is covered with a conductive rubber portion, and a part of the conductive rubber portion in the ribbon width direction is provided on the carcass. A method for producing a pneumatic tire, comprising connecting to a conductive sheet made of conductive rubber. 3. The method for manufacturing a pneumatic tire according to claim 1, wherein the conductive rubber portion is disposed in an area of 1/5 or more and less than 1 of the entire circumference of the tire. A tread rubber made of non-conductive rubber has a conductive portion made of conductive rubber with one end exposed on the ground surface and the other end reaching the side surface of the tread rubber, and side walls on both sides of the tread rubber. A pneumatic tire with rubber ends,
The sidewall rubber is formed by winding a rubber ribbon made of non-conductive rubber in a spiral shape along the tire circumferential direction in a region extending inwardly in the tire radial direction from the side surface of the tread rubber,
The rubber ribbon is the surface facing the mosquitoes carcass is covered with a conductive rubber portion,
The conductive rubber portion is connected to the conductive portion exposed on the side surface of the tread rubber, and is adjacent to the tire radial direction as a result of the rubber ribbon being spirally wound. A pneumatic tire characterized by being connected to each other . A tread rubber made of non-conductive rubber has a conductive portion made of conductive rubber with one end exposed on the ground surface and the other end reaching the side surface of the tread rubber, and side walls on both sides of the tread rubber. A pneumatic tire with rubber ends,
  The sidewall rubber is formed by winding a rubber ribbon made of non-conductive rubber in a spiral shape along the tire circumferential direction in a region extending inwardly in the tire radial direction from the side surface of the tread rubber,
  The rubber ribbon is in the carcass at least in a region in contact with the side surface of the tread rubber.
The opposing surface is covered with a conductive rubber part,
  Part of the conductive rubber portion in the ribbon width direction is connected to a conductive sheet made of conductive rubber provided on the carcass, a pneumatic tire characterized by the above.

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