KR100687647B1 - Tire mold with improved bead ring - Google Patents

Abstract

A tire mold with an improved bead ring is provided to improve structure of the bead ring of the tire mold to remarkably increase productivity of a tire manufacturing process. A tire mold with an improved bead ring comprises upper and lower molds, a tread mold, and a bead ring(2). The tread mold is coupled with the upper and lower molds to form a tread of a tire. The bead ring is coupled with upper and lower inner peripheries of the upper and lower molds to form a bead part(11) of the tire. The bead ring includes a first contact surface, a second contact surface, and a first curved part. The first contact surface is in contact with a lower end of the bead part. The second contact surface is in contact with a bladder(20) to contact an outer surface of the tire with the tire mold. The first curved part has a predetermined radius and is formed between the first contact surface and the second contact surface.

Description

TIRE MOLD WITH IMPROVED BEAD RING}

1 is a schematic view showing a conventional vulcanization mold for tires.

FIG. 2 is a cross-sectional view illustrating an bead ring in FIG. 1. FIG.

3 is a cross-sectional view showing a bead portion of a tire vulcanized by a conventional vulcanization mold for tires.

Figure 4 is a cross-sectional view showing the bead ring in the vulcanization mold for tires according to the present invention.

FIG. 5 is a partially enlarged cross-sectional view of the bead ring in FIG. 4. FIG.

Figure 6 is a cross-sectional view showing the bead portion of the tire vulcanized by the vulcanization mold for tires according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: lower mold, 2: bead ring

2a: first contact surface, 2a-1: inclined surface

2a-2: horizontal plane, 2b: first curved portion

2c: second contact surface, 2c-1: inclined surface

2c-2: vertical surface, 2c-3: second curved portion

10: tire, 11: bead

20 bladder

The present invention relates to a vulcanization mold for a tire having an improved bead ring, and more particularly, when vulcanizing a tire using the vulcanizing mold, it is possible to suppress the extraction occurring at the bead toe portion of the tire to remove the extraction after the tire is formed. By improving the structure of the bead ring of the vulcanization mold so that no additional trimming process is required, the present invention relates to a vulcanization mold for a tire that can greatly improve working conditions and productivity.

In general, tires are extruded compounding rubber mixed with various chemicals such as carbon black and sulfur, which is a kind of black pigment, and natural rubber, which is a raw material, or topping the compounding rubber to a cord or a wire. After the green tire is completed through a molding process of combining various semi-finished products cut through the rolling process by a molding machine, the green tire is finally put into a vulcanization mold and subjected to a vulcanizing process of applying high pressure and high heat for a predetermined time. do.

As shown in FIG. 1, the vulcanization mold for vulcanizing the green tire includes a pair of upper and lower molds 51 and 52 recessed in the shape of the tire to form an inner surface having the same shape as that of the finished tire. And a tread mold 53 coupled to the outer circumferences of the upper and lower molds 51 and 52 to form a tread of the tire, that is, a tread having a pattern of a plurality of grooves and blocks to be in contact with the road surface when the tire is driven to cause friction. ) And a bead ring (54) for coupling the upper and lower inner peripheries of the upper and lower molds 51 and 52 to form the bead portion 61 of the green tire 60.

Such a vulcanization mold, when the green tire 60 to be vulcanized in the lower mold 52 and lowering the upper mold 51, the tread mold 53 is retracted with the lowering operation of the upper mold 51 The green tire 60 is wrapped, and the bladder 70 installed inside the green tire 60 expands to squeeze the green tire 60 to the inner side of each mold, thereby vulcanizing the green tire 60. will be. At this time, the bead portion 61 of the green tire 60 is vulcanized while being pressed against the bead ring 54.

However, in the conventional vulcanization mold for tires, since the contact surface 55 of the bead ring 54 in contact with the bladder 70 is in a straight line, the strong pressure of the bladder 70 that expands during tire vulcanization is increased. When it is transmitted to the green tire 60, the rubber of the inner surface of the bead portion 61 flows down between the bladder 70 and the contact surface 55, at which time the flow of rubber is completed as shown in FIG. At the end of the bead toe (Bead Toe, 62) of the tire, it is molded to the pointed protruding downwards.

Extraction of the bead toe part 62 as described above not only causes a poor appearance of the finished tire, but also may cause an accident during driving by lowering the performance of the bead part 61.

Accordingly, in the related art, in order to remove the extraction as described above after the tire vulcanization process, only a separate trimming process is performed. Due to such an additional process, the number of manufacturing processes and the equipment cost of the tire are increased, thereby increasing the working conditions and productivity. There was a problem that this greatly reduced.

Therefore, the present invention has been made to solve the conventional problems as described above, when the tire is vulcanized by using a vulcanization mold, suppression of extraction occurring in the bead toe portion of the tire to further trim the removal after extraction The object of the present invention is to improve the working conditions and productivity in manufacturing tires by improving the structure of the bead ring of a vulcanization mold so that a process is not required.

In order to achieve the above object, the present invention is coupled to the upper and lower molds, the outer periphery of the upper and lower molds, the tread mold for forming the tread of the tire, and the upper and lower inner periphery of the upper and lower molds for forming the bead portion of the tire In the vulcanization mold for tires composed of bead rings,

The bead ring is formed from the end of the first contact surface which is in contact with the lower end of the bead portion to form a bent second contact surface in contact with the bladder for contacting the outer surface of the tire to the vulcanization mold in a chevron shape, and the first contact surface It is characterized in that the structure between the second contact surface is configured to be curved to have a first curved portion of a predetermined radius.

In addition, in the present invention, the radius of the first curved portion is characterized in that 1 to 5mm.

In addition, in the present invention, the first contact surface is composed of an inclined surface inclined toward the bead toe side of the lower end of the bead, and a horizontal plane extending horizontally from the end of the inclined surface to the point of view of the curved portion so as to contact the bead toe. The length of the horizontal plane is characterized in that 1 to 10mm.

In addition, in the present invention, the second contact surface is composed of an inclined surface which is inclined at an angle to the inside of the bead ring at the end of the first curved portion, and a vertical surface extending vertically from the end of the inclined surface to the lower end of the bead ring. The first contact surface and the second contact surface may be curved to have a second curved portion having a predetermined radius.

In addition, in the present invention, the radius of the second curved portion is characterized in that 5 to 15mm.

In the present invention, the angle is an angle between a vertical line vertically lowered at the end of the first curved portion and a tangent line which intersects the vertical line in contact with the inclined surface, and is 15 to 25 degrees.

In the present invention, the second contact surface is characterized in that the distance from the vertical line vertically lowered from the end of the first curved portion to the vertical plane is 4 to 10mm.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a cross-sectional view showing the bead ring in the tire vulcanization mold according to the present invention, Figure 5 is a partial enlarged cross-sectional view of the bead ring in Figure 4, Figure 6 is a vulcanization mold for tires according to the present invention It is sectional drawing which shows the bead part of a vulcanized tire.

The vulcanization mold for tires according to the present invention is connected to the outer periphery of the upper and lower molds as in the prior art, and the tread mold for forming the tread of the tire, and the beads for joining the upper and lower inner peripheries of the upper and lower molds to form the bead of the tire. It consists of a ring. In FIG. 4, only the main parts are illustrated by omitting the lower mold and the tread mold in order to simplify the drawing. In FIG. 4, '1' represents a lower mold and '2' represents a bead ring.

In the vulcanizing mold having such a structure, when the tire is vulcanized, the tire is installed inside the bottom of the bead and the tire in order to prevent rubber extraction from the bead toe portion located inside the bottom of the bead of the tire. The structure of the bead ring in contact with the bladder for making the outer surface in close contact with the vulcanization mold.

That is, the bead ring 2 according to the present invention is connected to the first contact surface 2a which is in contact with the lower end of the bead portion 11 of the tire 10 and the end of the first contact surface 2a to be bladder ( And a second contact surface 2c in contact with 20, wherein the second contact surface 2c is formed to be bent substantially in a chevron shape, and a predetermined radius is between the first contact surface 2a and the second contact surface 2c. It has a curved structure to have a first curved portion (2b) of.

Herein, the radius R1 of the first curved portion 2b is preferably in the range of 1 to 5 mm. The reason is that when the radius R1 is 1 mm or less, the curved portion 2b of the bead ring 2 is sharply formed, which may cause cracking of the bladder 20 when it is in contact with the bladder 920. This is because if the radius R1 is 5 mm or more, the curved portion 2b of the bead ring 2 may be excessively curved, thereby reducing the extraction prevention effect generated in the bead toe portion 12.

Further, the first contact surface 2a is an inclined surface 2a-1 that is inclined toward the bead toe portion 12 side of the lower end of the bead portion 11, and the bead toe portion at the end of the inclined surface 2a-1. It consists of the horizontal surface 2a-2 which runs horizontally to the starting point of the said 1st curved-surface part 2b so that it may contact with (12). At this time, the first contact surface (2a) may be formed only in the structure of the inclined surface (2a-1) without the horizontal surface (2a-2), but to form a horizontal surface of a suitable length to suppress the extraction of the bead toe part 12 Good to do. In this case, the length L of the horizontal plane 2a-2 is preferably in the range of 1 to 10 mm. If the length L of the horizontal surface 2a-2 is 10 mm or more, when assembling the finished tire formed by using the vulcanization mold on the wheel, the contact area between the bead part 11 and the wheel is too small and the bead part (11) It is not preferable because there is a possibility that the durability is significantly reduced.

On the other hand, the second contact surface 2c is an inclined surface 2c-1 which is inclined at a predetermined angle θ to the inside of the bead ring 2 at the end point of the first curved portion 2b, and It consists of a vertical surface (2c-2) vertically extending from the end of the inclined surface (2c-1) to the lower side of the bead ring (2), and between the first contact surface (2c-1) and the second contact surface (2c-2) It is a structure curved to have the 2nd curved-surface part 2c-3 of a predetermined radius. Although the radius R2 of the said 2nd curved-surface part 2c-3 does not need to be specifically limited, It is preferable to set it in the range of 5-15 mm.

An angle θ of the inclined surface 2c-1 intersects the vertical line VL vertically lowered at the end of the first curved portion 2b and the inclined surface 2c-1 and intersects the vertical line VL. As an angle between tangential lines, it is preferable that it is 15-25 degrees. When the angle θ of the inclined surface 2c-1 is out of the range, the bladder 20 expanded by the high temperature and high pressure cannot sufficiently compress the green tire 10 to the mold, thereby causing the bead toe part 12 It is not preferable because the extraction that occurs at) cannot be effectively prevented.

In particular, the second contact surface 2c is formed such that the distance D from the vertical line VL vertically lowered from the end of the first curved portion 2b to the vertical surface 2c-2 is 4 to 10 mm. good. If the distance D is 4 mm or less, it is not preferable because sufficient crimping in the contact section of the bead ring 2 and the bladder 20 (see 'A' in Fig. 4) cannot be expected, and the distance ( When D) is 10 mm or more, since sufficient adhesive force cannot be provided to the bead toe part 12 in the 1st curved-surface part 2b part of the bead ring 2, it is unpreferable.

When vulcanizing the green tire using the vulcanization mold according to the present invention configured as described above, when the strong pressure of the bladder 6 expanding inside the tire is applied to the green tire 4, the lower part of the bladder and the bead part Since the rubber on the inner side of the bead portion flowing down between the bead toe of the bead is suppressed by the curved portion of the bead ring 5, the bead having a good shape as shown in FIG. 6 without extracting from the bead toe portion as before. You can get wealth.

Table 1 shows the results of extraction of the extraction after the tire prototype using the vulcanization mold according to the present invention having such a structure compared with the prior art.

Item Minor Severe Very severe No occurrence Prior art 10 books 35 copies 55 books - The present invention - - - 100 books

In Table 1, the production standard of tire prototype was 12R22.5, and when 100 prototypes were used, the degree of extraction from bead toe during vulcanization was determined according to the number of prototypes. In other words, if the extraction length is within 2 mm, there is no occurrence, and when the extraction length is 3 to 5 mm, it is 'slight', and when the extraction length is 5 to 8 mm, the extraction length is In the case of 8 mm or more, it was judged as 'very severe'.

As a result, in the case of the present invention, extraction of 100 prototypes did not occur, whereas in the prior art, 90% of 100 prototypes were severely extracted, and in particular, 55% were very severe.

As described above, when vulcanization of the tire using the vulcanization mold according to the present invention, no extraction occurs at the bead toe portion, so that there is no need for an additional trimming process for extraction removal after molding as in the prior art.

As described above, according to the present invention, by forming the contact surface of the lower end of the bead portion and the bead ring in contact with each of the bladder, it is possible to sufficiently suppress the extraction generated in the bead toe during vulcanization, so as to tire There is no need for an additional trimming process for extraction removal after molding, which can significantly improve working conditions and productivity.

Although the present invention has been described with respect to the preferred embodiment, the present invention is not limited thereto, and various modifications and applications will be possible to those skilled in the art without departing from the gist of the present invention.

Claims (7)

As a bead ring (2) to be coupled to the upper and lower molds, the outer periphery of the upper and lower molds for molding the tread of the tire, and the upper and lower inner periphery of the upper and lower molds to form the bead portion (11) of the tire In the vulcanization mold for tires configured, The bead ring 2 extends from the end of the first contact surface 2a which is in contact with the lower end of the bead part 11, and the second contact surface which is in contact with the bladder 20 for bringing the tire outer surface into close contact with the vulcanization mold ( 2c) is formed to be bent in a chevron shape, and is configured to be curved to have a first curved portion (2b) of a predetermined radius between the first contact surface (2a) and the second contact surface (2c) Vulcanization mold for tires. The method of claim 1, The curvature mold for tires, characterized in that the radius of the first curved portion (2b) is 1 to 5mm. The method of claim 1, The first contact surface 2a is an inclined surface 2a-1 which is inclined toward the bead toe portion 12 side of the lower end of the bead portion 11, and the bead toe portion 12 at the end of the inclined surface 2a-1. ) Is made up of a horizontal surface (2a-2) horizontally continued to the point of view of the first curved portion (2b), and the length of the horizontal surface (2a-2), the vulcanization for tires, characterized in that 1 ~ 10mm brother. The method according to any one of claims 1 to 3, The second contact surface 2c is an inclined surface 2c-1 that is inclined at an angle to the inside of the bead ring 2 at the end of the first curved portion 2b, and an end of the inclined surface 2c-1. It consists of a vertical surface (2c-2) that extends vertically to the lower side of the bead ring (2), the second curved portion (2c-3) of a predetermined radius between the first contact surface (2a) and the second contact surface (2c) Vulcanization mold for tires, characterized in that the curved to have. The method of claim 4, wherein The curvature mold for tires, characterized in that the radius of the second curved portion (2c-3) is 5 to 15mm. The method of claim 4, wherein The angle is an angle between a vertical line VL vertically lowered at the end point of the first curved portion 2b and a tangent line which intersects the vertical line VL in contact with the inclined surface 2c-1. Vulcanization mold for tires, characterized in that the. The method of claim 4, wherein The second contact surface (2c) is a vulcanized tire, characterized in that the distance from the vertical line (VL) vertically lowered at the end of the first curved portion (2b) to the vertical surface (2c-2) is 4 ~ 10mm. mold.

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