JPH10138714A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent steering stability performance by forming a side wall of a sipe of a matted fine irregular surface with specific surface roughness. SOLUTION: A pneumatic tire is furnished with a large number of blocks on which sipes are arranged on a tread, and a side wall of the sipe is formed of a matted fine irregular surface. Surface roughness (Rmax) of this sipe side wall is made about 0.2-0.3mm and it is actually made uniform. Consequently, even when large force is applied on the sipe in the grounding state, it shows such a behavior as if surfaces of sand paper are rubbed with each other, no sliding is caused on wall surfaces of sipe inwalls facing against each other, and consequently, there is no possibility that rigidity of the blocks on which the sipes are formed and/or of the rib is lowered.

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 having a block and / or a rib on a tread and a large number of sipes disposed on the block and / or the rib. It is.

[0002]

2. Description of the Related Art Conventionally, when a large number of sipes are arranged on blocks and / or ribs formed on a tread, a braking performance of a pneumatic tire is improved by an edge effect of the sipes. All season tires and studless
In a tire or the like, a large number of sipes are often formed on a tread. Further, such a tire in which a large number of sipes are formed on a tread is manufactured by vulcanizing with a vulcanizing mold in which a large number of blades are implanted.

[0003]

However, when the sipe is formed on the tread as described above, the braking performance of the pneumatic tire is improved by the edge effect of the sipe. Slip occurs on the wall surfaces facing each other, and the rigidity of the block and / or rib on which the sipe is formed is reduced.
As a result, the steering stability performance of the tire is reduced, uneven wear occurs, and further, the improvement of the braking performance on a wet road surface or an ice-snow road surface, which is the original purpose of the sipe, is not achieved. Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-58118, a height of 3 to 3.5 mm is provided so that the opposing wall surfaces of the sipe mesh with each other in a grounded state.
It has been proposed to provide a degree of irregularity, but in order to form such a sipe in a tire, it is necessary to vulcanize the tire with a vulcanization mold in which a number of blades with irregularities are implanted. In addition, it becomes extremely difficult to remove the tire from the mold after vulcanization, which causes troubles in tire production such as damage to the tire or blade.

[0004] An object of the present invention is to solve the above-mentioned problems of the prior art, and to prevent the tires from deteriorating in steering stability and causing uneven wear even if a sipe is formed in the tread. It is to provide a pneumatic tire.

[0005]

According to the present invention, there is provided a tire according to the present invention, comprising: a pneumatic tire having a tread provided with a plurality of sipes; (Rmax) is a pneumatic tire characterized by being formed on a matte-like fine uneven surface substantially uniform within a range of about 0.2 to 0.3 mm.

In the tire manufacturing method according to the present invention, a large number of blades for forming a sipe are implanted in the tread of the tire, and the side walls of the blades have a surface roughness (Rmax) of 0.2 to 0.3 mm. Substantially uniform within a range,
A pneumatic tire manufacturing method characterized by manufacturing a pneumatic tire by vulcanizing with a vulcanizing mold formed on a matte-shaped fine uneven surface.

A tire vulcanization mold according to the present invention is a pneumatic tire vulcanization mold having a large number of blades for forming a sipe in a tread of a tire.
Pneumatically characterized in that the side wall of the blade is formed with a matte-like fine uneven surface having a substantially uniform surface roughness (Rmax) in the range of about 0.2 to 0.3 mm. This is a tire vulcanizing mold.

As described above, the inner wall of the sipe has a height of 3 mm.
Providing such a degree of unevenness causes troubles in tire production such as difficulty in removing the tire from the mold after vulcanization, but the pneumatic tire vulcanization method and the pneumatic tire production method based on the present invention In the mold for use, the tire is removed from the mold as described above since the side wall of the blade is formed of a matte-like fine uneven surface having a surface roughness (Rmax) of about 0.2 to 0.3 mm. There is no fear that it will be difficult.

In the tire according to the present invention, the side wall of the sipe is formed with a matte-like fine uneven surface, and its surface roughness (Rmax) is substantially uniform within a range of about 0.2 to 0.3 mm. Therefore, even if a large force is applied to the sipe in the ground contact state, it behaves as if the surfaces of the sand paper are rubbed against each other, and the sipe inner wall does not slip on the opposing walls, and therefore the sipe does not There is no possibility that the rigidity of the block and / or the rib on which is formed is reduced. As a result, the steering stability performance of the tire is ensured, and further, the improvement of the braking performance on a wet road surface or an icy snow surface, which is the original purpose of the sipe, is ensured.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The tire according to the present invention, the tires according to the prior arts 1 and 2, and the tire according to the comparative example will be described in detail below. All tire sizes are 185/6
0R14.

The tire according to the embodiment is a pneumatic tire provided with a large number of blocks in which a sipe is disposed on a tread, wherein the side wall of the sipe is formed with a matte-like fine uneven surface,
The surface roughness (Rmax) of the sipe side wall is substantially uniform at 0.2 mm.

In the tire of Conventional Example 1, the side wall of the sipe is formed with a smooth surface, and the surface roughness (Rmax) of the sipe side wall.
) Is substantially the same as the tire of the above example, except that) is 0.05 mm.

The tire of Conventional Example 2 is different from that of Conventional Example 1 described above except that hemispherical irregularities having a diameter and a height of 3 mm are provided on the opposing inner walls of the sipe so as to mesh with each other in a grounded state. The tire is almost the same as the tire.

The tire of the comparative example is a pneumatic tire provided with a number of blocks on the tread similar to the tire of the example, except that no sipes are provided in these blocks. It is almost the same tire as the tire.

The tires of the above embodiment according to the present invention, the tires of Conventional Examples 1 and 2 and the tire of the comparative example were subjected to a comparative test of block rigidity and steering stability performance. In the comparative test of the block rigidity, the tread portion was peeled off from the test tire, and the shear stress when a load was applied was measured. The size of the sample was 100 mm both vertically and horizontally, and the load was 500 kg. The driving stability comparison test is a test driver's feeling evaluation based on the result of running a passenger car equipped with a test tire on a test course.

When the evaluation results are shown by an index with the result of the pneumatic tire of the comparative example being 100, the block rigidity of the pneumatic tire of Conventional Example 1 is 80, the steering stability is 92, and the conventional pneumatic tire is 92. The pneumatic tire of Example 2 had a block rigidity of 90 and a steering stability of 93. The pneumatic tire of the above embodiment according to the present invention had a block rigidity of 92 and a steering stability of 95. The higher the number, the better the performance.

[0017]

From the above results, it can be seen that the tire according to the embodiment according to the present invention is a tire excellent in block rigidity and steering stability as compared with the conventional tire.

Claims (3)

[Claims] 1. A pneumatic tire in which blocks and / or ribs are provided on a tread, and a large number of sipes are arranged on the blocks and / or ribs. (2) The surface roughness (Rmax) of the sipe side wall is 0.2 to 0.3 m
A pneumatic tire, which is substantially uniform within a range of about m. 2. A pneumatic tire vulcanizing mold having a plurality of blades for forming a sipe in a tread of a tire, wherein (1) a side wall of the blade is formed with a matte-like fine uneven surface. (2) The pneumatic tire is cured by vulcanizing with a vulcanizing mold in which the surface roughness (Rmax) of the blade side wall is substantially uniform within a range of about 0.2 to 0.3 mm. A method for manufacturing a pneumatic tire, which is manufactured. 3. A pneumatic tire vulcanization mold in which a number of blades for forming a sipe on a tread of a tire are implanted. (1) Side walls of the blade are formed with a matte-like fine uneven surface, 2) A pneumatic tire vulcanizing mold characterized in that the surface roughness (Rmax) of the blade side wall is substantially uniform within a range of about 0.2 to 0.3 mm.