JPH1159125A - Pneumatic tire and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the use of coloring rubber paint by making a tire recognition line include a broken color line provided with breaking parts having the specified number or more in the tire circumferential direction. SOLUTION: A tire recognition line 4 composed of one or more colored lines extending in the tire circumferential direction is provided on a tread surface 2 in a pneumatic tire 1. The tire recognition line 4 includes a broken color line provided with two or more breaking parts 5a, 5b, 5c and 5d and the like in the tire circumferential direction. Therefore, the use quantity of coloring rubber paint can be decreased in comparison with a case where the tire recognition line is continuously painted in the tire circumferential direction, and rubber chipping, cracking, and partial abrasion such as boring of the color rubber painted part can be effectively restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire provided with a tire identification line extending in a tire circumferential direction on a tread surface.

[0002]

2. Description of the Related Art Conventionally, a tread rubber of a pneumatic tire is provided with a tire identification line composed of one or more colored color lines extending in a tire circumferential direction in order to specify a product number, a size, and the like of the tread rubber. . The tire identification line is drawn as a continuous straight line on the upper surface of the tread rubber which becomes the tread surface using a drawing device as disclosed in Japanese Patent No. 2568945, for example.

[0003] The tire identification line is usually made of a color rubber paint of a plurality of colors such as white, yellow, etc., which is conspicuous to the color of the tread rubber (usually black). By combining the number of lines and the number of lines, it is compatible with various types of tread rubber.

[0004] The tread rubber on which such tire identification lines are drawn is detected by a detection device such as a CCD camera, for example, to detect the color and number of the tire identification lines.
According to this, the product number of the tread rubber and the like are specified, and the tread rubber is sent to a predetermined production process and incorporated into a toroidal tire green cover, and a pneumatic tire is obtained by vulcanization molding. At this time, on the tread surface of the pneumatic tire, one place was cut off at a joint portion where the tread rubber was wound and jointed when manufacturing a tire cover or a tire identification line which is usually continuous over the entire circumference in the tire circumferential direction. The tire identification line remains.

[0005]

According to the study of the present inventors, the color rubber paint used for the tire identification line is:
Usually, since the optimum vulcanization time is different from that of the tread rubber, vulcanization of the tire green cover with the optimum vulcanization time of the tread rubber causes a rubber defect called a bear in the colored rubber paint portion of the tire identification line. It turned out to be easy. When such a tire identification line is located at the bottom of the tread groove formed on the tread surface, the TGC
There is also a problem that “cracking” called (Tread Groove Cracking) is likely to occur, and the durability of the tire is also reduced.

Further, since the color rubber paint and the tread rubber of such a tire identification line have different abrasion resistance of the rubber itself, uneven wear tends to occur in the color rubber paint, and particularly, in a tire for racing, etc. Thus, when used at high speeds, there is a problem in that the colored rubber paint is worn away from the tread rubber.

Further, in the conventional tire identification line continuously provided in the tire circumferential direction, it is necessary to prepare a large number of color rubber paints having different colors in order to specify various types of tread rubber. However, if the color of the color rubber paint alone cannot be used, the number of tire identification lines may increase, and the amount of the color rubber paint applied on the tread surface tends to increase. Such a problem as described above appears remarkably.

[0008] The present inventors have grasped new problems relating to the tire identification line of such pneumatic tires and have conducted intensive studies on these problems. As a result, the tire identification line was found to have two or more discontinuities in the tire circumferential direction. It has been found that various tread rubbers can be distinguished while reducing the amount of the colored rubber paint based on the inclusion of the discontinuous color line having the portion.

Further, in order to efficiently provide a discontinuous color line having such a discontinuous portion on the tread rubber,
The inventor has found that a colorless transfer line having a break in the tire circumferential direction is transferred by using a substantially gear-shaped transfer roller having a concave non-transfer portion formed on the outer peripheral surface.

As described above, an object of the present invention is to provide a pneumatic tire having a tire identification line capable of specifying various types of tread rubbers while reducing the amount of color rubber paint used, and a method of manufacturing the same. .

[0011]

According to the first aspect of the present invention,
A pneumatic tire provided with a tire identification line consisting of one or more colored color lines extending in a tire circumferential direction on a tread surface, wherein the tire identification line has two or more discontinuous parts in a tire circumferential direction. It is characterized by including a line.

Further, the invention according to claim 2 is the pneumatic tire according to claim 1, wherein the discontinuous color line comprises a discontinuous line having a discontinuous portion including a broken line or a dashed line.

According to a third aspect of the present invention, there is provided an extruding step of extruding an unvulcanized and sheet-like tread rubber from an extruder; A transfer step of transferring a tire identification line extending in the tire circumferential direction by bringing the attached transfer roller into close contact with the transfer roller, wherein the transfer roller has a concave non-transfer portion on the outer peripheral surface. By forming the formed substantially gear shape, a discontinuous color line having a discontinuous portion in the tire circumferential direction is transferred.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The pneumatic tire 1 of the present embodiment includes:
A pneumatic tire provided with a tire identification line 4 composed of one or more colored color lines extending in a tire circumferential direction on a tread surface 2, wherein the tire identification line 4 has two or more discontinuous portions 5a in the tire circumferential direction. , 5b, 5
c,... are provided.

The pneumatic tire 1 is exemplified by, for example, a radial tire for a passenger car. In this example, a vertical groove T1 extending in the tire circumferential direction on the tread surface 2, and a vertical groove T1
1 and a lateral groove T2 extending in a direction intersecting with the tread groove T2.
Are formed.

In the embodiment shown in FIG. 1, the tire identification line 4 exemplifies a line composed of one interrupted color line 6. Note that the color line refers to a line colored so that the color of the tread surface 2 can be recognized. In the present embodiment, the interrupted color line 6 is provided at substantially the center of the tread surface 2, that is, along the tire equator. In addition, the discontinuous color line 6 of the present embodiment shows a preferable aspect provided on the tread surface 2 without being located at the groove bottom of the tread groove T.
This can prevent such a problem as the TGC.

In the present embodiment, the interrupted color line 6 is provided with two or more interrupted portions 5a, 5a in the tire circumferential direction.
b, ... (generally referred to simply as "interruption portion 5") are illustrated in a broken line shape extending in the tire circumferential direction.

FIG. 2 is a plan view of the discontinuous color line 6 of the tread rubber (tread groove is not shown).
As shown in (a), in order to facilitate line pattern recognition, it is preferable that the break portions 5 are arranged at equal pitches P in the tire circumferential direction. Here, the length L1 in the tire circumferential direction of one break portion 5 is preferably 5 to 100 mm, more preferably 20 to 80 mm. It is desirable that the equal pitch P is, for example, 10 to 100 mm. In this example, L1 <P is set.

If the width W of the colored portion 6 in the tire axial direction is too small, the detection accuracy at the time of identification tends to decrease. Conversely, if the width W is too large, the amount of the colored rubber paint used increases. Therefore, it is desirable that the thickness is preferably 1 to 15 mm, more preferably 1 to 10 mm, and still more preferably 1 to 7 mm.

As described above, the two or more discontinuous portions 5a, 5b, 5c,.
The use of the color rubber paint can be reduced as compared with the conventional tire identification line drawn continuously in the tire circumferential direction by including the discontinuous color line 6 having the In addition, it is possible to effectively suppress uneven wear and the like that can be eclipsed.

The length L of the break 5 in the tire circumferential direction
By providing a change in 1 or the repetition pitch P, that is, by setting a plurality of line types of the discontinuous color line 6, it is possible to identify various types of tread rubber without changing the color of the tire identification line 4. Therefore, productivity can be improved by reducing the number of types of color rubber paints, and tire manufacturing costs can be significantly reduced.

The broken color line 6 has a length twice as long as the length L1 in the tire circumferential direction of the broken portion 5 and a pitch P as shown in FIG. Can be made equal. According to this, it becomes possible to provide the tire identification line 4 with approximately half the color rubber paint of the related art.

In addition to the above-described embodiment, the interrupted color line 6 may be formed as a dashed line as shown in FIG. 2 (c). In addition, various line types may be employed as long as they have two or more breaks, such as a two-dot chain line and a three-dot chain line.

Further, as shown in FIG. 3A, the tire identification line 4 is composed of a plurality of color lines, and is a combination of a continuous color line 10 extending continuously in the tire circumferential direction and the discontinuous color line 6. Can also be configured. Also in this case, the amount of the colored rubber paint used can be reduced as compared with a conventional pneumatic tire in which all the tires are continuously formed in a continuous color line in the circumferential direction of the tire. When the tire identification line 4 is composed of a plurality of tires, the number is preferably five or less, and it is sufficient that at least one of the tire identification lines 4 includes the discontinuous color line 6.

As shown in FIG. 3B, when the tire identification line 4 is composed of a plurality of color lines,
It is preferable that all of them are constituted by the interrupted color lines 6. As a result, the amount of the colored rubber paint used can be further reduced, and bears and the like can be effectively suppressed. Note that the tire identification line 4 may use not only a straight line but also a curve, a zigzag line, or the like.

The color rubber paint used for the color line may be, for example, 20 to 100 parts by weight of a coloring pigment based on 100 parts by weight of one or more rubber polymers selected from natural rubber, SBR, BR and the like. If necessary, a mixture of zinc white, sulfur, a vulcanization accelerator, a softener and the like dissolved in an organic solvent such as volatile oil or triol can be used.

The above-mentioned interrupted color line 6 is stored in a pattern, for example, in advance, is imaged by the detection means 12 (shown in FIG. 4) such as a CCD camera, and is collated with a pattern stored in a computer in advance. Can specify the product number or the like.

Next, a method for manufacturing a pneumatic tire having the discontinuous color line 6 will be described. As shown in FIG. 4, such a pneumatic tire includes an extrusion step of extruding an unvulcanized and sheet-like tread rubber G from an extruder (not shown), and a step of extruding the tread rubber G sent from a conveyor. A transfer step of transferring a tire identification line 4 extending in the tire circumferential direction by bringing a transfer roller 9 having a paint C of a color different from the tread rubber G adhered to the outer peripheral surface thereof into close contact with the upper surface thereof; It is important that the 9 has a substantially gear shape in which a concave non-transfer portion 9a is formed on the outer peripheral surface.

As the paint C, the color rubber paint can be preferably used. The transfer roller 9 can form the discontinuous portions 5a, 5b,... By forming a substantially gear-like shape having the concave non-transfer portion 9a, thereby forming a discontinuous portion on the tread surface 2 in the tire circumferential direction. 5
a, 5b,... can be transferred. The discontinuous color line 6 can draw a plurality of line types by preparing a plurality of transfer rollers in which the arrangement of the concave non-transfer portions 9a is changed.

By contacting the transfer roller 9 with a paint application roller 11 having a color rubber paint adhered to the outer peripheral surface, the color rubber paint can be continuously supplied to the outer peripheral surface of the transfer roller 9. Further, it is preferable to use, for example, ferrite for the paint application roller 11.

Then, by producing and vulcanizing a raw tire cover using such a tread rubber G, a discontinuous color line having two or more discontinuous portions 5 in the tire circumferential direction in which the amount of the color rubber paint used is small. 6 can be manufactured.

[0032]

As described above, according to the first and second aspects of the present invention, two tire identification lines are provided in the tire circumferential direction.
By including the interrupted color line having the above-mentioned interrupted portion, the amount of the colored rubber paint used can be reduced as compared with the conventional tire identification line drawn continuously in the tire circumferential direction, and the rubber of the colored rubber paint portion can be reduced. It is possible to effectively suppress defects, TGC, and even eccentric wear.

Further, by providing a change in the length of the discontinuous portion in the circumferential direction of the tire, the repetition pitch, and the like, that is, by providing a plurality of types of discontinuous color lines, a plurality of types of treads can be provided without changing the color of the tire identification line. Rubber can be identified. Therefore, the number of colors of the colored rubber paint can be reduced, productivity can be improved, and tire manufacturing costs can be significantly reduced.

According to the third aspect of the present invention, the paint is cut off in the circumferential direction of the tire on the upper surface of the tread rubber by a very simple structure in which the transfer roller is formed in a substantially gear shape having a concave non-transfer portion. A discontinuous portion can be easily formed, whereby a discontinuous color line having a discontinuous portion in the tire circumferential direction can be easily transferred to the tread surface. Further, by manufacturing and vulcanizing a raw tire cover using such a tread rubber, a pneumatic tire having a discontinuous color line with a small amount of a color rubber paint can be manufactured. In addition, as for the interrupted color line, plural kinds of line types can be drawn by preparing a plurality of transfer rollers whose concave arrangement is changed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a pneumatic tire according to an embodiment.

FIGS. 2A to 2C are plan views of a tread rubber used for manufacturing the pneumatic tire according to the present embodiment.

FIGS. 3A and 3B are plan views of a tread rubber used for manufacturing the pneumatic tire of the present embodiment.

FIG. 4 is a schematic side view for explaining a method of manufacturing a pneumatic tire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread surface 3 Color line 4 Tire identification line 5a, 5b,...

Claims (3)

[Claims] 1. A pneumatic tire having a tire identification line comprising one or more colored color lines extending in a tire circumferential direction on a tread surface, wherein the tire identification line has two or more breaks in a tire circumferential direction. A pneumatic tire comprising a discontinuous color line having a portion. 2. The pneumatic tire according to claim 1, wherein the discontinuous color line comprises a discontinuous line having a discontinuous portion including a broken line or a dashed line. 3. An extruding step of extruding an unvulcanized and sheet-like tread rubber from an extruder, and a transfer roller having a paint of a color different from that of the tread rubber adhered to an outer peripheral surface of the upper surface of the tread rubber. A transfer step of transferring a tire identification line extending in the tire circumferential direction by causing the transfer roller to have a substantially gear shape having a concave non-transfer portion formed on an outer peripheral surface. A method for manufacturing a pneumatic tire, wherein a color line having a break in a circumferential direction of the tire is transferred.