JP3422715B2 - Pneumatic tire - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having an annular decorative portion which can improve the visibility and appearance of a mark provided on a sidewall portion without deteriorating durability and the like.

[0002]

2. Description of the Related Art Improving the visibility when markings such as letters, figures, and symbols are arranged on the side wall part, and making unevenness on the side wall surface at the joint part and the winding end of the carcass inconspicuous, etc. For this purpose, conventionally, it has been generally practiced to provide an annular decorative portion having a large number of ridges by a process utilizing chemical corrosion or a mechanical process to improve the appearance.

[0003]

However, when dirt or dirt adheres between the ridges, the dirt is difficult to remove, and depending on the shape of the ridges, the visibility of the mark is impaired and the side wall surface is cracked. Etc. may occur, which may affect the durability.

Therefore, the present invention is based on the fact that the directionality, cross-sectional shape, dimensions, etc. of the ridge are specified, and it is excellent in stain-removing property and the visibility and appearance of the mark are improved without deteriorating the durability and the like. The purpose is to provide a pneumatic tire that can be used.

[0005]

In order to achieve the above object, the invention of claim 1 of the present application is a pneumatic tire in which an annular decorative portion is formed in a sidewall portion, wherein the annular decorative portion is A base surface substantially parallel to the surface of the sidewall portion, having a plurality of ridges having inclined wall surfaces on both sides and protruding parallel to each other with a small gap Wg between them on the base surface; The angle θ1 between the inclined wall surfaces is 60
~ 120 degrees, the angle θ2 of the ridge with respect to the tire circumferential direction is 60 to 75 degrees, the crest length Wp between the ridge peaks in the tire circumferential direction is 0.8 to 2.0 mm, and the radial direction from the base surface to the ridge peak is Ridge height h of 0.3-0.8 m
m, the small gap Wg on the base surface is 0.3 mm or less, and the curvature radius R of the arc connecting the base surface and the inclined wall surface is 0.05 to 0.20 mm. .

[0006] In the invention of claim 2, the annular decorative portion forms a rib-like body that passes through the end portion of the ridge and is higher than the ridge peak at the inner edge and the outer edge that are radially inward. It is characterized by having done.

Further, in the invention of claim 3, the annular decoration portion includes marks such as characters, figures, and symbols, and the marks have a smooth flatness of JIS surface roughness s1 of 25S or less. And a surface roughness s2 of the ridge.
Is smoother than the surface roughness s1 of the flat portion.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a part of a pneumatic tire 1. In the pneumatic tire 1, a sidewall portion 3 connecting a tread portion 2 and a bead portion 4 has an annular shape which is substantially concentric with the axis of the tire. The decorative portion 5 is formed.

In the present example, the annular decorative portion 5 has an inner rib-like body 6L along an inner edge EL radially inward thereof,
It is surrounded by an outer rib-shaped body 6U along the outer edge EU, and this decorative portion 5 includes a large number of ridges 7. In this example, the decorative portion 5 includes a mark 9 such as a character, a figure, and a symbol, and the ridge 7 is arranged around the mark 9.

The ridge 7 is shown in cross section in FIG.
(A-A cross section), a triangular cross-section is formed in which inclined wall surfaces 10A and 10B (generally referred to as inclined wall surface 10) are provided on both sides of the summit P, and a surface F of the sidewall portion 3 is formed. On a base surface 11 substantially parallel to the base surface 11, a small gap Wg is formed on the base surface 11 so as to be parallel to each other. It should be noted that the base surface 11 is generally at the same height level as the surface F, as illustrated, but it may be located below (inside the tire) or above (outside the tire) the surface F. .

Further, in this example, each ridge 7 has substantially the same shape and size in cross section, and the inner edge EL and the outer edge E are the same.
Substantially linear with a predetermined inclination angle between U and
In addition, the tires are arranged almost uniformly over the entire circumference.

The ridge 7 is formed in accordance with the following decorative specifications, which improves the stain removal property and improves the visibility and appearance of the mark 9 without deteriorating the durability. .

That is, the angle θ1 between the inclined wall surfaces 10A and 10B is 60 to 12
The angle θ2 (shown in FIG. 1) of the ridge 7 with respect to the tire circumferential direction is 60 to 75 degrees, and the crest length Wp in the tire circumferential direction between the ridge peaks P, P is 0.8 to 2.0 mm. The ridge height h in the radial direction from the base surface 11 to the ridge crest P is 0.3 to 0.8 mm, the small gap Wg on the base surface 11 is 0.3 mm or less, the base surface 11 and the inclined wall surface 10. The radius of curvature R (shown in FIG. 3) of the circular arc 12 connecting 0 and is 0. It is regulated to 05 to 0.20 mm, respectively.

If the peak length Wp is less than 0.8 mm, dirt, sand, etc. enter into the recesses between the ridges 7 and adhere to the ridges 7, which makes it difficult to remove them even after washing. . On the other hand, when it exceeds 2.0 mm, the ridge pattern is too rough and the appearance is deteriorated.

If the height h of the ridge is less than 0.3 mm, there is no effect of improving the visibility such as the loss of stereoscopic effect. On the contrary, if the height h exceeds 0.8 mm, the amount of protrusion of the ridge 7 becomes excessive and unnecessary. Cause an increase in weight.

If the small gap Wg exceeds 0.3 mm, the portion where the reflection of light with the mark 9 is the same is increased, and the visibility is not improved. If the small gap Wg is not provided, it becomes difficult to secure the stain removal property, cracks such as cracks are easily formed in the bottom portion between the ridges 7, and the light and shade are reduced to impair the stereoscopic effect. . Therefore, the small gap Wg is preferably at least 0.1 mm or more.

If the angle θ1 is less than 60, the summit P
Is too acute and rubber breakage or the like is likely to occur, which tends to reduce durability. On the other hand, if it exceeds 120 degrees, the direction of reflection of light with respect to the mark 9 becomes close, and the visibility cannot be improved.

Generally, in a tire having a low flatness ratio, since the flexible region is narrow and the degree of bending in the sidewall portion 3 is large, crack damage such as cracks or breaks occurs on the surface of the sidewall portion 3. It is easy to see that this crack is at a right angle or 45 to the tire circumferential direction.
It turned out that it tends to extend in the direction of degrees. Therefore,
It is extremely disadvantageous to form the ridge 7 along this direction, and durability can be improved by setting the angle θ2 of the ridge 7 in the range of 60 to 75 degrees which is the intermediate direction. If the angle θ2 is less than 60 degrees or exceeds 75 degrees, cracking is likely to occur due to the influence of the bending.

From the viewpoint of durability, the radius of curvature R of the arc 12 is required to be 0.05 to 0.20 mm.
If the thickness is less than 05 mm, the edge between the base surface 11 and the inclined wall surface 10 becomes substantially edge-shaped, and crack damage is likely to occur. On the other hand, when the thickness exceeds 0.2 mm, the flat surface portions of the base surface 11 and the inclined wall surface 10 are reduced, so that light reflection is weakened and the effect of improving the visibility is reduced.

Since the decorative portion 5 formed by the ridge 7 improves the visibility due to the difference in the reflection angle of light, the mark 9 is classified into the JIS surface roughness s1 of 25S or less (mirror surface side). ) Smooth flat part 9A
Is preferably used. In particular, from the viewpoint of visibility, the surface roughness s2 of the ridge 7, that is, the surface roughness s2 of the inclined wall surface 10, the base surface 11 and the arc 12 may be made smoother than the surface roughness s1 of the flat portion 9A. desirable. This makes the mark 9 more prominent. 1 In this example, the mark 9 is formed only by the flat portion 9A, but in addition to the flat portion 9A, a ridge,
Surface parts such as grain can be mixed, and in such cases,
It is good to outline the mark 9 by the flat portion 9A. When the ridge is provided in the mark 9, it can be formed with a decorative specification different from that of the ridge 7, but at least the peak length and the ridge height are preferably smaller than the ridge 7.

Further, in order to facilitate the end treatment of the ridge 7, it is preferable to provide the rib-like bodies 6L and 6U as in this example, and for this reason, the rib-like bodies 6L and 6U are provided.
Is formed higher than the ridge crest P passing through the end of the ridge 7. This is because without the rib-shaped bodies 6L and 6U, the ridge crests P intermittently project from the surface F of the sidewall portion 3 at the ends, so that the appearance is remarkably deteriorated. The protrusion height h1 of the bodies 6L and 6U from the ridge peak P is preferably 0.5 mm or more. The upper limit is not particularly limited, but it is generally 2.0 mm or less in terms of appearance.

[0022]

Example A tire (size 195 / 65R15) having a decorative portion using a ridge having the decorative specifications shown in Table 1 was prototyped, and each sample tire was tested for appearance, visibility and durability. The specifications other than Table 1 are the same.

The test method is as follows. -The appearance can be seen from various directions outdoors on a sunny day.
The quality of the appearance is indicated by an index with Comparative Example 1 being 100 by sensory evaluation. The larger the index, the better.・ Visibility is visible from various directions outdoors on a sunny day.
The distance at which the characters can be read is measured and displayed as an index with Comparative Example 1 as 100. The larger the index, the better.・ Durability was measured by using a drum tester and using an internal pressure (180 kp
a), the rim (15 × 5 1/2) and the load (505 kgf) are run at a speed of 80 km / h, and the distance to the occurrence of damage in the sidewall is displayed as an index with Comparative Example 1 as 100. is doing. The larger the index, the better.

[0024]

[Table 1]

[0025]

Since the present invention is constructed as described above,
Not only does it have excellent stain removal properties, but it can also improve the visibility and appearance of the mark without compromising durability.

[Brief description of drawings]

FIG. 1 is a side view of a tire according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing a sectional shape of a ridge.

FIG. 3 is a cross-sectional view showing an enlarged circular arc.

[Explanation of symbols]

3 Side wall part 5 decoration department 6U, 6L rib-like body 7 Ridge 9 marks 9A flat part 10, 10A, 10B inclined wall surface 11 Base 12 arcs EL inner edge EU outer edge F surface P Ridge summit

Continuation of the front page (56) Reference JP-A-7-164831 (JP, A) JP-A-8-318717 (JP, A) JP-A-8-318716 (JP, A) JP-A-10-297222 (JP , A) JP-A-9-11713 (JP, A) Actual development 60-160207 (JP, U) Actual development 62-22105 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB) (Name) B60C 13/00-13/02

Claims (3)

(57) [Claims] 1. A pneumatic tire having an annular decorative portion formed on a sidewall portion, wherein the annular decorative portion has inclined wall surfaces on both sides on a base surface substantially parallel to the surface of the sidewall portion. In addition, the base surface is provided with a large number of ridges which are parallel to each other with a small gap Wg therebetween, and the ridge has an angle θ1 between the inclined wall surfaces of 60 to 12
0 degree, the angle θ2 of the ridge with respect to the tire circumferential direction is 60 to
75 degrees, the tire crest length Wp between the ridge peaks is 0.8 to 2.0 mm, the radial ridge height h from the base surface to the ridge peak is 0.3 to 0.8 mm, and The small gap Wg on the base surface is 0.3 mm or less, and the radius of curvature R of the arc connecting the base surface and the inclined wall surface is 0.0.
A pneumatic tire having a decorative specification of 5 to 0.20 mm. 2. The ring-shaped decorative portion has a rib-like body which passes through an end portion of the ridge and is higher than a ridge peak at an inner edge and an outer edge of the ring-shaped inner portion in a radial direction. The pneumatic tire according to claim 1. 3. The annular decorative portion includes a mark such as a character, a figure, and a symbol, and the mark has a smooth flat portion having a surface roughness s1 according to JIS of 25S or less.
The pneumatic tire according to claim 1 or 2, wherein the surface roughness s2 of the ridge is smoother than the surface roughness s1 of the flat portion.