JPH04275136A - Preparation of pneumatic tire - Google Patents

Abstract

PURPOSE:To obtain a tire excellent in appearance and durability by forming the embossed mark of a side wall part using a side wall strip wherein different color rubber is embedded in rubber for a side wall. CONSTITUTION:The side wall part 3 of a pneumatic tire is formed from a side wall strip 11 consisting of black rubber 9 for a side wall and different color rubber 10 having a color other than black. That is, the side wall strip 11 is formed by embedding the different color rubber 10 for forming an embossed mark 7 displaying a character mark, for example, a trade mark, a firm name or a product number in the base part 12 composed of the rubber 9 for the side wall. The embossed mark 7 is formed by vulcanizing a green cover tire in a vulcanizing mold having a recessed part for forming the embossed mark 7 provided to the inner surface thereof to mold a vulcanized tire and buffing the surface of the protruding part formed by the recessed part to expose the different color rubber.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pneumatic tire that can form a uniquely colored raised mark, such as a white letter, on the sidewall of the tire.

0002

2. Description of the Related Art Marks such as lettering formed on the sidewalls of tires are often made using so-called white letters, in which white letters are embossed on a black tire base.

As shown in FIG. 3, the sidewall portion a of a tire having such white letters has conventionally been made of black rubber, consisting of an upper sidewall rubber a1 continuous with the tread portion, and a white rubber for forming raised marks. rubber a2, a lower sidewall rubber a3 made of black rubber and connected to the clinch apex b, and a vinyl rubber a4 made of thin black rubber that covers the white rubber a2;
The tire has a raised part c near its maximum width, and by buffing and removing the vinyl rubber a4 in this part, white letters, for example, are exposed.

[0004] Also, such a sidewall portion a is shown in FIG.
As shown in , the upper sidewall portion rubber a1;
A sidewall strip s consisting of a lower sidewall rubber A3, a white rubber A2 connecting the upper and lower sidewall rubbers A1 and A3, and a vinyl rubber A4 was attached to the carcass, and had a recessed part for forming the raised part C. It is formed by vulcanization in a vulcanization mold.

[0005]

[Problems to be Solved by the Invention] However, the sidewall rubbers a1 and a3 are made of a rubber material with excellent flexibility and weather resistance.
Since the physical properties are different from that of No. 4, there will be a difference in color at the boundary, which will impair the appearance.

[0006] Also, upper and lower sidewall rubber a1, a3
Since the rubber is separated with the white rubber a2 in between, the flexibility in the sidewall portion is rather poor, and the running performance tends to be impaired.

[0007] The present invention is based on forming a sidewall strip in which a different colored rubber for forming raised marks is embedded inside a base made of rubber for the sidewall, thereby improving the appearance and durability of a pneumatic tire. The purpose is to provide a manufacturing method.

[0008]

[Means for Solving the Problems] The present invention provides a pneumatic tire having a carcass that passes from the tread portion to the sidewall portion and is folded back at the bead core of the bead portion, and has a unique raised mark on the surface of the sidewall portion. A method for manufacturing a tire, which comprises forming a sidewall strip made of sidewall rubber and having a different color rubber for forming raised marks embedded inside the base having a width from near the bead to near the end of the tread. By vulcanizing a raw cover tire having a sidewall portion formed by adhering the sidewall strip in a vulcanization mold having a recessed portion on the inner surface for forming an embossed mark, After molding a vulcanized tire in which a raised part is provided on the surface of the sidewall part, the surface of the raised part is buffed to expose the different colored rubber, thereby forming the raised mark made of the different colored rubber. This is a method for manufacturing pneumatic tires characterized by the following.

[0009]

[Function] Forms a sidewall strip made of sidewall rubber and embedded with different colored rubber for forming raised marks inside the base of the width from near the bead part to near the end of the tread part, thereby forming a sidewall strip for raw cover tires. At the same time, the raw cover tire is vulcanized and molded, and then the protrusions on the surface of the sidewall portion are buffed to expose the different color rubber. Therefore, vinyl rubber can be omitted, and the appearance can be improved by eliminating the difference in color at the border.

[0010] Furthermore, since the different-colored rubber is embedded in the base made of the sidewall rubber, the sidewall rubber is continuously interposed between the carcass and the surface other than the embossed mark is the sidewall rubber. The structure is covered with rubber, which helps improve the flexibility and weather resistance of the sidewall portion, and can also increase the durability of the tire.

[0011]

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 obtained by the manufacturing method of the present invention has a carcass 6 that passes from a tread portion 2 through a sidewall portion 3 and is folded back at a bead core 5 of a bead portion 4, and has a carcass 6 on the surface of the sidewall portion 3. A uniquely colored embossed mark 7 is exposed.

In this embodiment, the carcass 6 is a radially arranged body in which carcass cords are arranged at an angle of 70° to 90° with respect to the tire equator, and the carcass cords include steel cords, nylon, polyester, and rayon. Fiber cords such as

The sidewall portion 3 is formed by a sidewall strip 11 consisting of a black sidewall rubber 9 and a different color rubber 10 having a color other than black. As the sidewall rubber 9, a well-known rubber material with excellent flexibility and weather resistance is used.

The sidewall strip 11 is made of the sidewall rubber 9 and has character symbols such as trademarks, trade names, product numbers, etc. displayed inside the base 12, which has a width extending from the vicinity of the bead portion 4 to the vicinity of the 2nd end of the tread portion. Different colored rubber 10 for forming raised marks 7 is embedded. Such a sidewall strip 11 has a cross-sectional shape as shown in FIG. Since the rubber 9 is continuously interposed above and below and the surface of the sidewall portion 3 is covered with the sidewall rubber 9, the flexibility and weather resistance of the sidewall portion 3 can be improved. The sidewall strip 11 may be formed by directly embedding the different colored rubber 10 by extrusion molding, or by later attaching the sidewall rubber 9A on the outer surface of the different colored rubber 10 shown by the dashed line in FIG. may be buried. Note that the different color rubber 10 is usually white in color, but it may be in a color other than white.

The sidewall strip 11 is attached to the outer periphery of the carcass pasted together on a forming drum together with tread rubber forming a tread portion, thereby forming the sidewall portion 3 and completing a green cover tire. In addition, in the raw cover tire, the upper end of the sidewall strip 11 is connected to the wing rubber 2 at the edge of the tread portion 2.
0, and its lower end is connected to the clinch apex 21 on the outer surface of the bead core 5. In addition, by vulcanizing this raw cover tire in a vulcanization mold having a recess on the inner surface for forming the raised mark 7, a bulge formed by the recess near the maximum width of the tire is formed as shown in FIG. Part 1
5 on the surface of the sidewall portion 3 is molded.

Further, by buffing the sidewall rubber 9 on the surface of the raised portion 15, the different color rubber 1
0 is exposed, and the embossed mark 7 such as white letter made of the different colored rubber 10 is exposed.

[0017]

[Effects of the Invention] As described above, the method for manufacturing a pneumatic tire of the present invention uses a sidewall strip in which a different color rubber is embedded inside the sidewall rubber to form a raised mark on the sidewall. It is possible to remove the vinyl rubber that conventionally covered the different colored rubber, thereby eliminating the color change caused by this and improving the appearance. Furthermore, since the sidewall rubber is not separated into upper and lower parts, the flexibility and weather resistance of the sidewall portion can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a part of a pneumatic tire obtained by the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view illustrating a sidewall strip.

FIG. 3 is a sectional view illustrating a prior art.

FIG. 4 is a sectional view showing the sidewall strip.

[Explanation of symbols]

2 Tread part 3 Sidewall part 6 Carcass 7 Embossed mark 9 Rubber for sidewall 10 Different color rubber 11 Sidewall strip 12 Base 15 Raised part

Claims (1)

[Claims] 1. A method for manufacturing a pneumatic tire having a carcass that passes from a tread portion to a sidewall portion and is folded back at a bead core of a bead portion, and has a uniquely colored raised mark on the surface of the sidewall portion, comprising: Forming a sidewall strip made of rubber for sidewalls and embedding different colored rubber for forming raised marks inside the base of the width extending from near the bead part to near the end of the tread part, and adhering the sidewall strip. By vulcanizing a raw cover tire having a sidewall portion formed by the method in a vulcanization mold having a recessed portion on the inner surface for forming an embossed mark, the raised portion formed by the recessed portion is formed on the surface of the sidewall portion. A pneumatic tire characterized in that, after molding a vulcanized tire provided with a vulcanized tire, the surface of the raised portion is buffed to expose the different colored rubber, thereby forming the raised mark made of the different colored rubber. manufacturing method.