JP3007825B2 - 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 capable of improving the distinguishability of a display mark provided on a sidewall surface of a tire.

[0002]

2. Description of the Related Art In general, in tires, display marks such as letters and symbols such as trade names and trademarks are widely provided on sidewall surfaces. For example, as shown in FIG. 8, in a black tire, the mark m is entirely formed of white rubber, and a rubber of a different color from the tire main body is used.
In addition, the discrimination effect is enhanced by being raised from the sidewall surface s. In recent years, in particular, tires having excellent appearance are particularly preferred for tires for passenger cars, and there has been a demand for improved appearance of display marks.

[0003]

In the conventional display mark, although the color is different by using white rubber, the entire outer surface of the mark has the same gloss as the outer surface of the surrounding sidewall portion, so that the discrimination effect is not obtained. Insufficient, poorly changing and degraded appearance. In addition, it takes time and effort to process because a different kind of rubber is attached to the display mark.

[0004] In order to solve the above-mentioned problem, there has been proposed an arrangement in which a marker area for displaying a display mark is arranged in a mesh pattern with narrow grooves intersecting each other.

[0005] However, according to the above proposal, although the discriminating property is slightly improved, the depth of the groove cannot be increased because the mark area is formed as a mesh pattern. Due to factors such as irregular reflection of the incident light, the difference in brightness from the surface other than the marker area is reduced, and as a result, the above problem has not been completely solved.

According to the present invention, the outer surface of the display mark provided on the side wall surface is formed by a large number of narrow grooves extending in a certain direction, and the groove depth of the narrow groove and the pitch between the grooves are regulated, whereby the display mark is formed. It is an object of the present invention to provide a pneumatic tire that can be easily displayed with a mark while enhancing the discriminability.

[0007]

According to the present invention, an outer surface of a display mark provided on a side wall surface of a tire is formed in an uneven shape provided with a large number of narrow grooves extending in a predetermined direction and arranged in parallel at an equal pitch. And the depth of the narrow groove b
Is not less than 0.3 mm and not more than 1.0 mm, the groove depth b / a, which is the ratio of the groove depth b to the groove pitch a, is not less than 0.5 and not more than 2.2, and the narrow groove has a groove wall surface. Is the side
0 degree or more and 25 degrees or less with respect to the normal perpendicular to the wall surface
This is a pneumatic tire that opens outward at a lower angle .

Preferably, the groove depth b of the narrow groove is 0.5 mm or more, and more preferably, the groove depth ratio b / a is 1.0 or more and 2.0 or less.

The display mark means a character, a symbol, a figure, a pattern, or the like for displaying a trade name or a trademark.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the figure, a pneumatic tire 1
Has a display mark 3 on a side wall surface 2 which is an outward surface of the side wall portion 12.

The display mark 3 refers to a character, a symbol, a figure or a pattern for displaying a trade name or a trademark. In the present embodiment, it is formed by the letter "D" shown in FIG. 1, and will be described below with reference to the drawings.

In the present embodiment, the contour of the display mark 3 is formed by a raised portion 13 which is raised at a smaller height than the regular sidewall surface 2 in this example. In this example, a small-width edging portion 14 is provided along the peripheral edge of the display mark 3, and a display portion 15 in which a number of narrow grooves 4 are formed is surrounded by the edging portion 14. Is established.

The display mark 3 may be formed with a display portion having the above-mentioned structure flush with the sidewall surface 2 without providing a raised portion, or may be formed in a recess formed in the sidewall surface 2. The display unit having the above configuration can be formed.
However, in order to secure the rubber gauge of the side wall portion and not to reduce the strength of the tire, it is preferable to form a raised portion as shown in FIG.

The edging portion 14 is provided to prevent the generation and growth of cracks that easily occur at the bottom of the narrow groove 4 due to the elastic deformation and external force of the tire itself during tire running. When the mark is provided flush with the side wall surface 2 or provided in a recess recessed from the side wall surface, the mark may be omitted.

In the area of the display mark 3, the narrow grooves 4 extend in a fixed direction and are arranged in parallel at an equal pitch. Further, a groove that crosses the narrow groove 4 must not be provided.

In this embodiment, the narrow groove 4 is formed in an inverted trapezoidal shape as shown in FIG. The narrow groove 4 has a groove depth b.
Is not less than 0.3 mm and not more than 1.0 mm, and the groove depth ratio b / a, which is the ratio of the groove depth b to the groove pitch a, is not less than 0.5 and not more than 2.2. The narrow groove 5 is formed so as to open outward at an angle θ of 0 ° or more and 25 ° or less with respect to a normal line N perpendicular to the sidewall surface 2.

The directions of these narrow grooves 4 are arranged at an angle to the tire radial line as shown in FIG. It may be arranged in the direction of the tire radial line as shown in FIG. 5 (B), or in the direction perpendicular to the tire radial line as shown in FIG. 5 (C).

The area of the display mark 3 is defined by such narrow grooves 4.
The light irradiating the sidewall surface 2 of the tire is formed by a smooth surface except for the display mark 3 because the sidewall surface 2 is formed by a smooth surface.
While the light is reflected, in the region of the display mark 3, the light hits the wall surface of the narrow groove 4 and reflects the light in a direction different from the side wall surface 2.

Therefore, when the side wall surface 2 of the tire is viewed, the area of the display mark 3 has a small amount of reflected light, and the difference between the outside and the area of the display mark 3 is noticeably different. The display mark 3 can be displayed even when the 3A is formed of rubber of the same color and the same color as other sidewall surfaces.

When the groove depth b is less than 0.3 mm, the difference between the narrow groove 4 and the side wall surface 2 other than the display mark 3 by visual observation is small and the discrimination is inferior. At times, bears are likely to occur. It is preferable that the groove depth b is 0.5 mm or more in order to enhance the discriminability.

When the groove depth ratio b / a is less than 0.5, the difference in brightness from the other side wall surface 2 is small, and it is difficult to identify the display mark 3, while the ratio b / a is low. 2.
If it exceeds 2, rubber will not easily flow into the groove, and a bear tends to be formed. Note that the groove depth ratio b / a is 1.0 or more and 2.
By setting the range to 0 or less, the above-mentioned disadvantage can be further eliminated.

Further, if the inclination angle θ of the groove wall surface 5 with respect to the normal line N is inwardly opened at 0 ° or less, molding becomes difficult, and if it becomes larger than 30 °, the gap between the groove wall surface 5 and another side wall surface becomes large. The difference in lightness and darkness is reduced, and the discrimination is inferior. The inclination angle θ is in the range of 15 to 25 degrees .

When a groove is provided which intersects the narrow grooves 4 having the above-described structure and the display mark is formed in a mesh pattern, the area of the groove wall surface 5 is reduced, so that the area of the other wall surface 2 is reduced. The difference in light and shade of the image is reduced. Therefore,
The narrow groove 4 must be limited to a groove provided only in a certain direction.

The display mark 3 is formed at the time of forming the tire contour during the vulcanization molding. As shown in FIG. 7, a recess 21 is formed in the tire molding die A at a position corresponding to the area of the display mark 3, and a number of protrusions 22 are formed in the recess 21. Form.

In vulcanization molding, sidewall rubber 2G
Is pressed toward the tire mold A,
The display mark 3 as shown in FIG.
Is formed.

The display mark 3 is formed by attaching a thin sheet having a different rubber composition or color to the surface of the side wall rubber 2G and performing the vulcanization process.
May be bonded together.

The narrow groove 4 has a groove depth b and a groove depth ratio b /
In a range where a satisfies the regulation value, in a groove cross-sectional shape orthogonal to the groove bottom line of the narrow groove 4, a V-shape as shown in FIG. 3 or an outer surface and a groove bottom as shown in FIG. It may be formed in a wavy shape to be formed, and the groove cross-sectional shape of the narrow groove 4 may be asymmetric such as a sawtooth shape.

Further, as shown in FIG. 6, a border area 16 having a height h of 5 mm or less may be provided so as to surround the display mark 3. Thus, the form of the present invention can be modified into various forms.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Regarding the display mark 3 according to the above configuration, Table 1
(Examples 1 to 6)
The appearance and quality were confirmed. In addition, display marks (comparative examples 1 to 4) other than the configuration of the present application were also prototyped, and their performances were compared. The evaluation was performed according to the following criteria.

A) Blackness and Contrast As shown in Table 2, the blackness and the contrast were evaluated in five steps by ten scorers, and the total score was displayed. b) Occurrence of bears Each sample is visually determined. Table 1 shows test results
Shown in

[0031]

[Table 1]

[0032]

[Table 2]

As a result of the test, the example of the present invention had higher discriminability than the comparative example and no bear was generated.

[0034]

As described above, the pneumatic tire of the present invention, having the above-mentioned structure, can display the display mark more clearly than the conventional one, enhance the discriminability, and improve the molding efficiency. There is no bear and stable quality can be achieved.

In addition, press molding using a vulcanizing mold can be employed, so that production is easy and cost can be reduced. Further, since the display can be performed without changing the color unlike the conventional display mark, the manufacturing cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line XX.

FIG. 3 is a cross-sectional view showing another embodiment of the narrow groove.

FIG. 4 is a cross-sectional view showing another embodiment of the narrow groove.

FIGS. 5A, 5B, and 5C are plan views each showing the direction of a narrow groove.

FIG. 6 is a perspective view showing another embodiment.

FIG. 7 is a cross-sectional view illustrating an example of a manufacturing method.

FIG. 8 is a perspective view showing a conventional technique.

[Explanation of symbols]

 2 Side wall surface 3 Display mark 4 Narrow groove 5 Groove wall surface a Pitch between grooves b Groove depth N Normal line

──────────────────────────────────────────────────続 き Continued on the front page (56) References Japanese Utility Model Showa 60-92604 (JP, U) Japanese Utility Model Showa 60-160207 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B60C 13/00-13/04

Claims (2)

(57) [Claims] 1. An outer surface of a display mark provided on a sidewall surface of a tire has an uneven cross section provided with a number of narrow grooves extending in a predetermined direction and arranged in parallel at an equal pitch. Groove depth b of 0.3 mm or more and 1.0 mm or less,
Groove depth b, which is the ratio of the groove depth b to the groove pitch a
/ A is not less than 0.5 and not more than 2.2, and the narrow groove has a groove wall surface perpendicular to the side wall surface.
Open at an angle of 0 ° or more and 25 ° or less with respect to the normal
A pneumatic tire characterized by forming a. 2. The narrow groove has a groove depth b of 0.5 mm or more, a groove depth ratio b / a of 1.0 or more and 2.
The pneumatic tire according to claim 1, wherein the value is 0 or less.