JP2002240509A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire for suppressing reduction of draining function after abrasion with affecting durability of the tire. SOLUTION: In this pneumatic tire having a drainage conduit 7 in the surface of a tread part 1, volume part 11 that is made of water soluble material and is equivalent to a continuous groove is buried in a non-groove part inside the surface of the tread part 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that maintains good drainage even after abrasion.

[0002]

2. Description of the Related Art Generally, a groove is provided on a tread surface of a pneumatic tire. If the road surface is wet, the tire slips through the water film, so that the water film is collected in the groove and drained. However, as the wear of the tread advances, the volume of the grooves provided on the tread surface of the pneumatic tire decreases, so that the drainage performance of the tire decreases. Conventionally, as a measure to prevent such a decrease in drainage performance, in retreaded tires, a groove is formed on the back side of the pre-cured tread, and when the tread wears, the groove on the back side is exposed, so that drainage of the groove part lost due to wear is performed. There are some that complement the functions.

However, when a hollow groove is provided inside the tread as in the above-mentioned retreaded tire, the rigidity of the tread is reduced, and the air in the hollow expands due to heating of the tread during running. However, there is a drawback that the durability of the resin is remarkably reduced.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire which suppresses a decrease in drainage after a certain amount of wear has progressed without affecting the durability of the tire. .

[0005]

A pneumatic tire according to the present invention is a pneumatic tire having a drain groove provided on a surface of a tread portion, and a continuous groove made of a water-soluble substance in a non-groove portion inside the tread surface. A substantial volume is buried.

As described above, since the volume equivalent to the continuous groove made of a water-soluble substance is buried in the non-groove portion inside the tread surface, the tread portion of the tire is worn and the continuous groove made of the water-soluble substance is worn. When the volume equivalent to the groove is exposed on the surface of the tread, the water-soluble substance is eluted by the water on the road surface, so that a new drain groove is formed in the tread to reduce the drainage of the tread after abrasion. Can be suppressed. In addition, as long as the wear does not reach the volume of the water-soluble substance, the solid structure of the tread is maintained, so that the durability is not reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1A and 1B show an example of a pneumatic tire according to the present invention, wherein FIG. 1A is a meridional sectional view, and FIG. 1B is a plan view of a tread.

In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion. A carcass layer 4 is mounted between the pair of right and left bead portions 3 and 3 so as to extend over the tread portion 1 and the sidewall portion 2, and an end portion in the tire width direction is wound up around the bead core 5 from the inside to the outside of the tire. ing. A plurality of belt layers 6 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1.

A plurality of main grooves (drain grooves) 7 are provided on the surface of the tread 1 in the circumferential direction of the tire, and a large number of lug grooves (drain grooves) 8 are provided from the center toward the shoulder. I have. Also, the rib 9 formed in the center portion
Has a volume 1 corresponding to a continuous groove made of a water-soluble substance.
1 is embedded so as to cover one circumference in the tire circumferential direction. The volume portion 11 is provided so as to occupy more than 50% of the groove depth of the main groove 7 from the surface of the tread, and the lowermost end reaches a position corresponding to the groove bottom of the main groove 7.

As the water-soluble substance used for the volume portion 11, a water-soluble polymer or a rubber composition containing 40% by weight or more of a water-soluble polymer is preferable. If less than 40% by weight,
It becomes difficult to elute the water-soluble polymer component. The water-soluble polymer is characterized by having a large number of polar groups having strong interaction with water in the molecule, and the polar groups include ionic groups, hydroxyl groups, amino groups, amide groups, ether groups and the like.

Representative examples of the water-soluble polymer include starch, processed starch, casein, glue, gelatin, gum arabic, sodium alginate, pectin and other natural polymers, carboxymethylcellulose, methylcellulose, and the like.
Semi-synthetic polymers such as viscose, and synthetic polymers such as polyvinyl alcohol, polyacrylamide, polyethyleneimine, sodium polyacrylate, polyethylene oxide, and polyvinylpyrrolidone, but are limited to the substances listed here. Not something. Incorporation into a tire as a composite requires partial compatibility with other rubber components, and blending with a diene rubber is preferred.

In the pneumatic tire having the above structure, when the tread portion is worn down to 50% of the depth of the main groove, the volume portion 11 of the water-soluble substance is exposed. A circumferential drain groove is formed at the bottom.
Therefore, it is possible to suppress a decrease in drainage after abrasion of the tread portion. Further, as long as the wear does not reach the volume of the water-soluble substance, the solid structure of the tread portion is maintained, so that the durability is not reduced.

FIGS. 2A and 2B show a pneumatic tire according to another embodiment of the present invention, wherein FIG. 2A is a meridional sectional view and FIG. 2B is a plan view of a tread portion.

In this embodiment, a water-soluble material is provided in the block 10 between the lug grooves 8 and 8 of the shoulder portion so as to be parallel to the lug grooves 8 and not to penetrate both ends toward the shoulder end and the main groove 7. Volume 1 equivalent to continuous groove made of material
1 'is buried. The depth of the volume portion 11 ′ is provided so as to occupy more than 50% of the groove depth of the lug groove 8 from the surface of the tread, and the lowermost end reaches a position corresponding to the groove bottom of the lug groove 8. . Other configurations are almost the same as the embodiment of FIG.

Also in this pneumatic tire, when the tread portion wears out and the volume portion 11 'is exposed, a water-soluble substance is dissolved by rainwater or the like to form a new lug groove, and drainage after the tread portion wears out. Can be suppressed. In addition, as long as the wear does not reach the volume of the water-soluble substance, the solid structure of the tread is maintained, so that the durability is not reduced.

In the above embodiment, the case of a radial tire has been described. However, the present invention is not limited to a radial tire, and the same configuration can be applied to a bias tire.

[0018]

As described above, according to the present invention, since the volume corresponding to the continuous groove made of a water-soluble substance is buried in the non-groove portion inside the tread surface, the tread portion of the tire is worn. When the volume portion corresponding to the continuous groove made of the water-soluble substance is exposed on the surface of the tread portion, the water is eluted by the road surface, so that a new drain groove is formed in the tread portion,
It is possible to suppress a decrease in drainage after abrasion of the tread portion. In addition, as long as the wear does not reach the volume of the water-soluble substance, the solid structure of the tread is maintained, so that the durability is not reduced.

[Brief description of the drawings]

FIG. 1 illustrates a pneumatic tire of the present invention, in which (A) is a meridional section and (B) is a plan view of a tread portion.

2A and 2B show a pneumatic tire according to another embodiment of the present invention, wherein FIG. 2A is a meridional sectional view, and FIG. 2B is a plan view of a tread portion.

[Explanation of symbols]

 Reference Signs List 1 tread portion 2 sidewall portion 3 bead portion 4 carcass layer 5 bead core 6 belt layer 7 main groove 8 lug groove 9 rib 10 block 11, 11 '(corresponding to continuous groove) volume portion

Claims (4)

[Claims] 1. A pneumatic tire in which a drain groove is provided on a surface of a tread portion, wherein a volume portion corresponding to a continuous groove made of a water-soluble substance is embedded in a non-groove portion inside the tread surface. 2. The drainage groove according to claim 1, wherein the volume corresponding to the continuous groove is provided in a region corresponding to the groove depth of the drainage groove at a position 50% or more of the depth of the drainage groove from the tread surface. Pneumatic tires. 3. The pneumatic tire according to claim 1, wherein a volume corresponding to the continuous groove extends in a tire circumferential direction and / or a tire width direction. 4. The pneumatic tire according to claim 1, wherein the water-soluble substance comprises a water-soluble polymer or a rubber composition containing the water-soluble polymer in an amount of 40% by weight or more.