JP2006199235A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire having a tread portion containing a high percentage of silica, which pneumatic tire maintains an effect of electric discharge to a road surface until the final stage of wearing without deteriorating the traveling characteristics of the tire. <P>SOLUTION: The pneumatic tire 1 has the tread portion 2 made of a low-conductive rubber composition containing a high percentage of silica, and a rubber structure portion other than the tread 2, which rubber structure portion is made of a high-conductive rubber composition containing a high percentage of carbon black. At least one circumferential groove is formed on the tread of the tread portion 2, where the circumferential groove communicates along the tire circumference. A conductive adhesive layer 8 is interposed at a joint face 2a on the circumference of the tread portion 2, and a conductive coating material 4 is applied at least to the wall of the circumferential groove on the tread of the tread portion 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire. More specifically, in a tire having a tread portion with a high silica content, the discharge action on the road surface is maintained until the end of wear without deteriorating the running characteristics of the tire. Related to pneumatic tires.

  Conventionally, a large amount of carbon black has been blended as a reinforcing material in the rubber constituting the tire. However, in recent years, in response to the demand for lower fuel consumption of vehicles, a large amount of silica is blended in the tread rubber instead of carbon black to reduce rolling resistance and improve wet performance. Tires are in practical use. However, the pneumatic tire having a tread portion in which a large amount of silica is blended in this way has a high electrical resistance of the tread portion, so that the static electricity charged on the vehicle cannot be discharged to the road surface and accumulated in the vehicle. Various problems such as generation of radio noise due to static electricity have occurred.

  As a countermeasure, a special member made of a conductive rubber sheet or conductive rubber string containing a large amount of carbon black is placed on a part of the tread and exposed to the surface of the tread to serve as a ground. Many proposals have been made (see, for example, Patent Documents 1 and 2).

However, since rubber with a large amount of silica and rubber with a large amount of carbon black have different wear resistance characteristics, the rubber with a large amount of carbon black wears out early, causing uneven wear on the tire tread. There was a problem that the running characteristics of the tire such as comfort and noise were deteriorated.
Japanese Patent Laid-Open No. 11-151907 JP-A-11-227415

  An object of the present invention is to solve the above-described conventional problems, and in a tire having a tread portion with a high silica content, the discharge action on the road surface until the end of wear is achieved without deteriorating the running characteristics of the tire. It is an object of the present invention to provide a pneumatic tire that maintains the above.

  In order to achieve the above object, the pneumatic tire of the present invention comprises a tread portion with a low-conductivity rubber composition with high silica content, and a rubber other than the tread portion with a high-conductivity rubber composition with high carbon black content. In the pneumatic tire which comprises a structure part and provided the peripheral groove which communicates with at least one tire peripheral direction in the tread part of the tread part, a conductive adhesive layer is interposed on the joint surface on the circumference of the tread part The conductive paint is applied to at least the groove wall of the circumferential groove on the tread surface of the tread portion.

  According to the present invention, a special member made of conductive rubber is not disposed in the tread portion, and a conductive adhesive layer is interposed on the joint surface on the circumference of the tread portion, and the circumference communicated with the tire in the circumferential direction. Since conductive paint is applied to the groove wall of the groove, there is no uneven wear on the tire tread until the end of wear of the tread part, so the running performance of the tire such as ride comfort and noise characteristics deteriorates I will not let you. In addition, the conductive paint applied to the groove wall of the circumferential groove and the conductive adhesive layer interposed on the joint surface of the tread part maintain the state of being connected until the end of wear. The static electricity of the vehicle can be reliably discharged to the road surface.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a tread portion of a pneumatic tire according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  In FIG. 1, a pneumatic tire 1 has a plurality of main grooves 3 extending in the tire circumferential direction on a tread surface of a tread portion 2. In the pneumatic tire 1 of the present invention, in order to reduce rolling resistance and improve wet performance, a rubber composition containing a large amount of a silica component in the rubber constituting the tread portion 2 is used. A rubber composition containing a large amount of carbon black is used for the rubber constituting the rubber structure. A conductive paint 4 is applied to the tread surface of the tread portion 2 including the groove wall of the main groove 3, and a conductive adhesive layer 8 is interposed on the joint surface 2 a (see FIG. 2) on the circumference of the tread portion 2. Has been. In FIG. 1, 5 is a carcass layer, 6a and 6b are belt layers, and 7 is a belt cover layer.

  Thus, the conductive paint 4 and the conductive adhesive layer 8 are given a role of an energization path so that the static electricity of the vehicle is efficiently discharged to the road surface. In addition, even when the vehicle is in an advanced stage, no special member made of conductive rubber is disposed on the tread portion, so that uneven wear does not occur on the tire tread, and the groove wall of the main groove 3 The conductive paint 4 applied to the surface and the conductive adhesive layer 8 interposed on the joint surface 2a of the tread portion 2 are maintained in a connected state, so that an energization path between the vehicle and the road surface is ensured until the end of wear. Thus, the static electricity of the vehicle can be reliably discharged to the road surface.

  In the above-described embodiment, the case where the conductive paint 4 is applied to the entire tread surface of the tread portion 2 including the groove wall of the main groove 3 is shown. However, the conductive paint 4 is applied only to the groove wall of the main groove 3. Further, the main groove 3 to which the conductive paint 4 is applied may be a circumferential groove communicating in the tire circumferential direction.

In the present invention, the conductive coating 4 applied to the tread part 2 and the conductive adhesive layer 8 interposed on the joint surface 2a of the tread part 2 are similar to the rubber constituting the rubber structure part other than the tread part 2. -It is good to set it so that it may consist of the rubber composition or resin composition which mix | blended Bon black highly, and the electrical resistance value of these compositions may be 10 < ⁷ > ohm * cm or less. Such adjustment of the electric resistance value is performed by selecting the type and blending ratio of carbon black. Thereby, the static electricity charged in the vehicle can be reliably discharged to the road surface. The rubber composition with high silica content constituting the tread portion 2 has an electric resistance value of more than 10 ⁷ Ω · cm, usually 10 ¹⁰ to 10 ¹² Ω · cm.

  The pneumatic tire of the present invention may be manufactured by the method described below.

  That is, when the tread rubber layer is formed by the step of extruding the tread rubber from the extruder and the step of cutting the tread rubber so as to match the tire circumference, the conductive paint 4 is applied to the surface of the tread rubber. The step of applying the conductive paint 4 may be applied to the surface of the tread rubber in any one of the two steps described above. The method of applying the conductive paint 4 is not particularly limited, but is preferably applied by a spray method from the viewpoint of workability, and the tread rubber is passed through the atmosphere in which the conductive paint 4 is sprayed. You should do it.

  Furthermore, a conductive adhesive is applied to the cut surface of the tread rubber layer in a stage where the thus obtained tread rubber layer is bonded to the outer peripheral side of the belt layer on the tire molding drum by a known means. Join on the outer circumference of the belt layer. After that, the molded body thus obtained is removed from the tire molding drum, bonded to the outer peripheral side of the tire body including a separately prepared carcass layer, and then expanded to an unvulcanized tire. Is obtained. The method of applying the conductive adhesive to the cut surface of the tread rubber layer may be brush coating or a spray method. Thereby, the conductive adhesive layer 8 is formed on the joint surface 2 a of the tread portion 2. Thereafter, the unvulcanized tire is vulcanized in a mold by a known method to become a product tire.

  The tread part 2 of the tread portion 2 of the vulcanized tire obtained in this way is in a state where the conductive paint 4 is coated on the entire surface including the groove wall of the circumferential groove. The conductive paint 4 described above may be applied to the surface of the tread portion 2 of the vulcanized tire without being applied to the surface of the tread rubber layer in the unvulcanized stage.

  As described above, the pneumatic tire according to the present invention applies conductive paint to the groove wall of the circumferential groove formed at least on the tread surface of the tread portion and communicates with the circumferential surface of the tire, and is electrically conductive on the joint surface of the tread portion. By interposing an adhesive layer, even for long-distance running, the discharge action on the road surface is maintained until the end of wear without deteriorating the running characteristics of the tire due to the occurrence of uneven wear. Therefore, there is no need to arrange a special ground rubber in the tread portion, and there is an advantage that it can be manufactured by a very simple method.

It is sectional drawing which shows the tread part of the pneumatic tire by embodiment of this invention. It is AA arrow sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 2a Joint surface 3 Main groove 4 Conductive paint 5 Carcass layer 6a, 6b Belt layer 7 Belt cover layer 8 Conductive adhesive layer

Claims (3)

The tread portion is composed of the low-conductivity rubber composition with high silica content, and the rubber structure portion other than the tread portion is composed of the high-conductivity rubber composition with high carbon black content. At least one tread portion is provided on the tread surface. In a pneumatic tire provided with a circumferential groove communicating with the tire circumferential direction,
A pneumatic tire in which a conductive adhesive layer is interposed on a joint surface on the circumference of the tread portion, and a conductive paint is applied to at least a groove wall of the circumferential groove on the tread surface of the tread portion. The electrical resistance value of the rubber structure part other than the conductive adhesive layer, the conductive paint and the tread part is 10 ⁷ Ω · cm or less, and the electrical resistance value of the tread part is larger than 10 ⁷ Ω · cm. The pneumatic tire according to claim 1. The pneumatic tire according to claim 1 or 2, wherein the conductive adhesive layer and the conductive paint are made of a rubber composition or a resin composition with a high carbon black content.

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