JP2012030690A - Studded tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a studded tire that prevents a stud from falling out from a tread rubber layer, while maintaining the travelling performance in driving on a snowy and icy road surface.SOLUTION: The studded tire includes studs embedded in the tread rubber layer. In the studded tire, the stud includes: a flange at which the stud abuts on an inner periphery of the tread rubber layer; and a body extended on the tread side from the flange and abutting on the inner periphery of the tread rubber layer through a rubber sheet covering around the body.

Description

  The present invention relates to a tire, and more particularly to a spike tire in which a drop of a spike pin embedded in a tread rubber layer does not occur.

Conventionally, as a winter tire traveling on an icy and snowy road surface, a spike tire having a spike pin driven so as to protrude from the tire tread surface is known.
For example, Patent Document 1 discloses a spike tire in which a flange portion positioned at the deepest portion of the tire tread in a state where the tire tread is driven is covered with a cover rubber having a characteristic that the hardness of the rubber changes due to a temperature change of the outside air. In a high-temperature environment, the frictional force against the road surface is reduced, while in the high-temperature environment, the frictional force against the road surface is reduced, thereby maintaining the anti-slip performance of the spike pin on the road surface. Spike tires have been proposed that can prevent the generation of dust.
However, the tire according to the cited document 1 has a very long metal portion that is in direct contact with the inner peripheral surface of the tire tread with respect to the entire length of the spike pin, and is generated during traveling due to the difference in hardness between the metal spike pin and the tire tread. Sufficient frictional force that resists pull-out force cannot be obtained, and a situation in which the spike pin falls off from the tire tread tends to occur.

JP 59-199308 A

  Therefore, in order to solve the above problems, the present invention provides a spike tire capable of maintaining running performance on an icy and snowy road surface and preventing the spike pin from falling off the tread rubber layer.

A first aspect of the present invention is a spike tire including a spike pin embedded in a tread rubber layer, the spike pin being in contact with the inner peripheral surface of the tread rubber layer, and from the flange portion to the tread side. The structure includes an inner peripheral surface of the tread rubber layer and a body portion that is in contact with each other via a rubber sheet coated around the tread rubber layer.
According to this configuration, since the body portion of the spike pin comes into contact with the inner peripheral surface of the tread rubber layer via the rubber sheet coated on the periphery, the pulling force generated during traveling between the spike pin and the tread rubber layer It is possible to obtain a sufficient frictional force to resist the spike pin and to prevent the spike pin from falling off.
Further, as a second configuration of the present invention, the rubber sheet has a thickness in the range of 0.5 mm to 2.0 mm.
According to this configuration, the adhesiveness between the spike pin and the rubber sheet can be ensured, and the spike pin covered with the rubber sheet can be easily manufactured.
Further, as a third constitution of the present invention, the rubber sheet is a compound having a melting point of 120 ° C. to 220 ° C. and a resin having a softening point before curing of 90 ° C. to 150 ° C., or a compound and a resin. The total amount of the compound and the resin is in a range of 0.5 to 25.0 parts by mass per 100 parts by mass of the rubber sheet.
According to this structure, since a rubber sheet is comprised by the said mixing | blending, it becomes possible to improve the adhesiveness with a spike pin very much.
Further, as a fourth configuration of the present invention, the rubber sheet has a viscosity measured at a shear rate of 750S-1 and a temperature of 100 ° C. according to ASTM D5099-93, and is 2.0 kPa · s or less, and As the physical properties of the rubber sheet after vulcanization, the tensile stress at 100% elongation was 5.0 Mpa or more, and the elongation at break was 200% or more.
According to this configuration, it is possible to ensure the workability of the extrusion work, and it is possible to improve the durability of the rubber.
Further, as a fifth configuration of the present invention, the resin is a thermosetting resin.
According to this configuration, it is possible to obtain sufficient elastic modulus and durability after vulcanization, and it is possible to improve the extrusion workability during rubber sheet processing and the durability of rubber.

It is sectional drawing of a spike tire. It is an expansion schematic of a spike pin. It is a table | surface which shows an experimental result.

FIG. 1 is a cross-sectional view of a spike tire 1. The structure of the spike tire 1 will be described with reference to FIG. The structure of the spike tire 1 is not limited to the following.
In the figure, a spike tire 1 is roughly composed of a bead core 2, a carcass 3, a belt layer 4, a tread rubber layer 5, and spike pins 6.
The bead core 2 is an aggregate of steel cords formed in an annular shape, and is a pair of members provided apart in the tire width direction. A carcass 3 extending in a toroidal shape is provided between the pair of bead cores 2 so as to straddle between the pair of bead cores 2, thereby forming a skeleton of the spike tire 1. A tread rubber layer 5 is formed on the crown portion Tc of the spike tire 1 from the carcass 3 to the outside in the radial direction, and a belt layer in which a plurality of belts are laminated in the radial direction inside the tread rubber layer 5. 4 is formed. The belt layer 4 suppresses protrusion due to the rotation of the crown portion Tc of the spike tire 1 and exhibits a so-called tagging effect while the vehicle is traveling.

On the outer surface of the tread rubber layer 5, a plurality of land portions 5B partitioned by a plurality of tread grooves 5A are formed. A plurality of spike pins 6 are driven into the land portion 5 </ b> B with respect to the driving holes 9 opened in advance. The driving hole 9 is a circular hole having a diameter slightly smaller than the diameter of each part of the spike pin 6, and is opened in advance by a mold during vulcanization or a piercing process after vulcanization.
In this example, a spike tire 1 having a so-called block pattern shape is illustrated, but the tread pattern of the spike tire 1 is not limited to this.

FIG. 2 is an enlarged schematic view showing a state in which the spike pin 6 is driven.
As shown in the figure, the spike pin 6 is a member formed of a metal such as iron or aluminum alloy, and is a flange portion positioned at the deepest portion of the driving hole 9 when driven into the tread rubber layer 5. 6A, a body portion 6B that extends radially outward from the flange portion 6A, that is, toward the tire tread surface, and a tip portion 6C that protrudes from the tip of the body portion 6B.
As shown in FIG. 1, the spike pins 6 are driven so as to be even on the left and right at positions shifted outward in the width direction from the center in the width direction of the spike tire 1. In addition, although illustration is abbreviate | omitted, the spike pin 6 is driven at equal intervals along the circumferential direction (rotation direction) of the spike tire 1, for example.

The flange portion 6 </ b> A is a flat cylindrical body that serves as a base of the spike pin 6, and prevents the spike pin 6 from falling off the tread rubber layer 5. The flange portion 6 </ b> A is a portion in which the outer peripheral surface is in direct contact with the inner peripheral surface 10 </ b> A that forms the driving hole 9 when the spike pin 6 is driven into the tread rubber layer 5.
The body portion 6B is a cylindrical body that extends toward the tire tread surface, and in a state in which the spike pin 6 is driven into the tread rubber layer 5, a friction region P in which the outer peripheral surface is surrounded by the inner peripheral surface 10B; It has a remaining portion exposed from the outer surface of the tread rubber layer 5.
The body portion 6B has a diameter Db smaller than the diameter Df of the flange portion. In addition, the diameter Df of the flange portion 6A is preferably selected from a range larger than 1.0 times and 2.0 times larger than the diameter Db of the body portion 6B.
This is because, when the diameter Df of the flange portion 6A is set to be larger than 2.0 times the diameter Db of the body portion 6B, when the spike pin 6 is driven into the drive hole 9, it corresponds to the body portion 6B in the drive hole 9. This is because the inner peripheral surface 10B is driven while the diameter is increased more than necessary, and it becomes difficult to ensure the adhesion between the body portion 6B and the inner peripheral surface 10B.

The outer peripheral surface of the friction region P of the body portion 6B is covered with the rubber sheet 7 with an adhesive over the extending direction. That is, when the spike pin 6 is driven into the tread rubber layer 5, the body portion 6 </ b> B comes into contact with the inner peripheral surface 10 </ b> B via the rubber sheet 7 that covers the outer peripheral surface. And since both the rubber sheet 7 and the internal peripheral surface 10B are rubber | gum, a strong frictional resistance will arise in the interface.
That is, the flange portion 6A of the spike pin 6 is in direct contact with the inner peripheral surface 10A of the driving hole 9, and the body portion 6B is indirectly connected to the inner peripheral surface 10B of the driving hole 9 through the rubber sheet 7 covered on the outer peripheral surface. It is the structure which touches. In other words, the rubber sheet 7 is covered only on the body portion 6B.

  The rubber sheet 7 is a diene rubber composition having high adhesion to metal. Examples of the diene rubber composition include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber and the like.

  The rubber composition contains a compound having a melting point of 120 ° C. to 220 ° C., and the compound is a bismaleimide. Specifically, N, N′-1,2-phenylenebismaleimide, N, N′-1,3-phenylenebismaleimide, N, N′-1,4-phenylenebismaleimide, N, N ′-( 4,4′-diphenylmethane) bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane and the like are preferable, and more preferable. Is N, N ′-(4,4′-diphenylmethane) bismaleimide.

  The rubber composition contains a resin having a pre-curing softening point of 90 ° C to 150 ° C. The resin is a thermosetting resin from the viewpoint of stability after vulcanization, and preferably contains at least one bismaleimide resin. Specific examples include bismaleimide resins and phenyl bismaleimide resins. Thereby, sufficient elastic modulus and durability can be obtained after vulcanization, and it is possible to improve the extrusion workability when processing the rubber sheet 7.

  The compound and resin have a total compounding amount in the range of 0.5 to 25.0 parts by mass per 100 parts by mass of the rubber composition and contain both the compound and the resin in a predetermined compounding amount, or the compound and the resin Only one of these is contained in a predetermined amount. When the total blending amount is a predetermined amount, it is possible to obtain a sufficient elastic modulus and breaking strength after vulcanization.

The viscosity of the rubber composition is 2.0 kPa · s or less when measured at a shear rate of 750S-1 and a temperature of 100 ° C. according to ASTM D5099-93. In addition, although extrusion workability | operativity at the time of rubber sheet 7 shaping | molding can be ensured by making clay into 2.0 kPa * s or less, when a viscosity exceeds 2.0 kPa * s, a fall of extrusion workability | operativity will be caused.
Further, the rubber composition after vulcanization has a tensile stress at 100% elongation of 5.0 MPa or more and an elongation at break of 200% or more, preferably 300% or more. Since the tensile stress of the rubber composition after vulcanization is 5.0 MPa or more and the elongation at break is 200% or more, it is possible to obtain durability against the tension of the rubber composition.

The tip portion 6C is press-fitted into the distal end portion of the remaining portion of the body portion 6B. The tip portion 6C is, for example, a cemented carbide such as tungsten steel, and is a cylindrical metal body protruding from the tip portion. The tip portion 6C is not limited to a cylindrical shape, and may be a polygon such as a quadrangle. The tip portion 6C is located on the central axis of the body portion 6B and has a smaller diameter than the body portion 6B.
The tip portion 6C generates a frictional force between the tire and the icy / snowy road surface by grounding on the icy / snowy road surface and scratching the ice during vehicle travel.

Hereinafter, with reference to FIG. 3, the result of the pull-out test performed on the spike pin 6 in which the body portion 6B is covered with the rubber sheet 7 will be described.
In the table of FIG. 3, Comparative Example 1 is a spike pin 6 that covers the rubber sheet 7 over the entire length L of the friction region P of the body portion 6B, and the pulling force in this example is 200N.
The comparative example 2 is a spike pin 6 that covers the rubber sheet 7 from the flange portion 6A side to a half (L / 2) of the total length L of the friction region P of the body portion 6B, and the pulling force in this example is 180N. .
Comparative Example 3 is a spike pin 6 that covers a rubber sheet 7 from the flange portion 6A side to one third (L / 3) of the total length L of the friction region P of the body portion 6B. Is 170N.
Conventional Example 1 is a spike pin 6 in which neither the body portion 6B nor the flange portion 6A is covered with the rubber sheet 7, and the pulling force in this example is 130N.
Conventional example 2 is spike pin 6 in which rubber sheet 7 is coated only on flange portion 6A, and the pulling force in this example is 140N.
The “spike pin pulling force” is a force required when pulling out the spike pin 6 driven into the tread rubber layer 5, and indicates that a larger pulling force number is more difficult to drop off.

As is apparent from the above experimental results, the pulling force of the spike pin 6 is greater when the body portion 6B is covered with the rubber sheet 7 than when the flange portion 6A is covered with the rubber sheet 7, and the tread rubber layer 5 and the rubber. It can be seen that the frictional resistance generated between the sheets 7 becomes large and is greatly improved.
Further, it can be seen that the pulling force of the spike pin 6 is improved by increasing the friction resistance generated between the tread rubber layer 5 and the rubber sheet 7 as the rubber sheet length in the entire length L of the friction region P is longer. Therefore, in order to prevent the spike pin 6 from falling off the tread rubber layer 5, it is preferable to cover the body portion 6B with the rubber sheet 7. More preferably, the entire length L of the friction region P of the body portion 6B is set to the rubber sheet 7. It is better to coat with.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the said embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made to the above-described embodiment, and it is obvious that such changes and modifications can be included in the technical scope of the present invention. It is clear from the description.

1 spike tire, 2 bead core, 3 carcass, 4 belt,
5 tread rubber layer, 6 spike pin, 6A flange, 6B body
6C Tip part, 7 Rubber sheet, 9 Driving hole, P Friction area.

Claims (5)

A spike tire comprising a spike pin embedded in a tread rubber layer,
The spike pin is in contact with the inner peripheral surface of the tread rubber layer;
A spike tire characterized by having a body portion that extends from the flange portion to the tread surface side and that comes into contact with an inner peripheral surface of the tread rubber layer and a rubber sheet that is covered around the inner peripheral surface.   The spike tire according to claim 1, wherein the rubber sheet has a thickness in a range of 0.5 mm to 2.0 mm. The rubber sheet contains, in the rubber component, a compound having a melting point of 120 ° C. to 220 ° C. and a resin having a softening point before curing of 90 ° C. to 150 ° C., or one of the compound and the resin,
The total compounding amount of the compound and the resin is a compounding amount in a range of 0.5 to 25.0 parts by mass per 100 parts by mass of the rubber sheet. Spike tires. The rubber sheet has a viscosity measured at a shear rate of 750S ⁻¹ and a temperature of 100 ° C. according to ASTM D5099-93 and is 2.0 kPa · s or less, and the physical properties of the rubber sheet after vulcanization are as follows. The spike tire according to any one of claims 1 to 3, wherein a tensile stress at 100% elongation is 5.0 Mpa or more and an elongation at break is 200% or more.   The spike tire according to claim 3 or 4, wherein the resin is a thermosetting resin.

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