JPH10113997A - Production of pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a pneumatic tire comprising an S/H(slim and high) type bead filler efficiently without causing defective molding. SOLUTION: A carcass ply 12 is provided in a tire molding device 30 comprising an enlarged diameter drum 32 and an expansion bladder 34. A filler sheet 26 having a projecting part 28 mainly comprising a filler part on the surface is mounted on the carcass ply 12 in a spread state and the diameter of the enlarged diameter drum 32 is enlarged. Then, by expanding the expansion bladder 34 and folding back the carcass ply 12, at the same time folding back the filler sheet 26 with a core art 22 serving as the core member, a pneumatic tire having an S/H type bead filler stretched to the tip part is produced between the fold back part of the carcass ply 12 and the main body part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a pneumatic tire, and more particularly to a method for manufacturing a pneumatic tire having an elongated bead filler.

[0002]

2. Description of the Related Art
In a pneumatic tire 200 as shown in FIG. 6, a bead core 204 in which a plurality of cords are twisted and a filler portion 206 mainly made of rubber are separately formed. For this reason, the bead core 204 is exposed, and there arises a problem that the terminal of the cord jumps up.
In order to prevent this, the terminal of the cord was held by bead tape or the like.

[0003] In order to eliminate the bead tape, the base side of the filler portion 206 is extended to bead core 204.
Some are wound around. This eliminates the need for bead tape.

[0004] Such a bead filler 202 is attached to both ends of a carcass ply 208 set in a molding machine. The molding machine includes an expanding drum for expanding the central portion of the carcass ply 208, and an expansion bladder adjacent to the expanding drum and for folding both ends of the carcass ply 208. The carcass ply 208 is wound and disposed around each peripheral surface of the diameter-enlargement drum and the expansion bladder. When the diameter expansion drum and the expansion bladder are operated in this state, the diameter of the carcass ply 208 is expanded at the central portion, and both ends are folded back. At this time, bead filler 20
Numeral 2 is arranged upright at the folded center portion of the carcass ply 208, and is wrapped by the folded carcass ply 208.

[0005] In recent years, a bead filler 210 of a slim and high type that is thinner than the bead filler 202 of the pneumatic tire 200 shown in FIG.
(See FIG. 7). Such a slim and high type (hereinafter, referred to as S / H type) bead filler 210 can moderate the rigidity step of the tire side portion.

However, as shown in FIG. 7, in the S / H type bead filler 210, since the filler portion 212 is elongated, when the bead core 214 is arranged below and it is intended to stand on the carcass ply 208. (FIG. 7
(See arrow A in FIG. 7A), the tip of the filler portion 212 may come into contact with the surface of the carcass ply 208 before its center due to its own weight, or the center may meander (see FIG. 7B). . As a result, if the carcass ply 208 is folded back in this state (see FIG. 7B), there is a possibility that a molding failure may occur due to the filler portion 212 that has not completely extended to the tip end. Further, since a gap is formed between the filler portion 212 and the carcass ply 208, air may enter the gap and a so-called air chamber may be generated. Thus, the S / H type bead filler 210 has a drawback that it is elongated and difficult to handle.

In order to improve this, it is conceivable to form the filler portion 212 of the S / H type bead filler 210 short and add a separate filler portion to the tip portion later, but the manufacturing process becomes complicated. Also, since there is no continuity of the filler portion, it is easy to separate easily, which is not preferable.

The present invention has been made in view of the above facts, and provides a method of manufacturing a pneumatic tire including a S / H type bead filler without causing molding defects. The purpose is to:

[0009]

According to the first aspect of the present invention,
A method of manufacturing a pneumatic tire using a tire molding machine having a diameter-enlarging drum that expands a central portion of a carcass ply and an inflation bladder that turns both ends of the carcass ply, the method comprising: An operation of laying a sheet-like filler on the carcass ply set in the above, further positioning a bead core at a predetermined position on the sheet-like filler, inflating the inflatable bladder, and folding back the end of the carcass ply Accordingly, the sheet-like filler is bent so as to be wound around the bead core, and an elongated bead filler is formed on a radial extension of the bead core.

According to the present invention, the sheet-like filler placed on the carcass ply placed on the expanding drum and the inflatable bladder is bent at the same time as the carcass ply is folded, and is placed on the sheet-like filler. By winding around the placed bead core, an elongated bead filler, that is, a so-called S / H type bead filler is formed. Thus, the S / H type bead filler can be formed from a state in which the sheet-like filler is sufficiently extended with respect to the carcass ply. Further, the tip of the S / H type bead filler does not come into contact with the carcass ply due to its own weight. As a result, the S / H type bead filler does not meander on the carcass ply, and it is possible to avoid generation of air chambers and molding defects.

Therefore, a pneumatic tire provided with an elongated so-called S / H type bead filler can be manufactured efficiently without causing molding defects.

The invention according to claim 2 is characterized in that a protrusion is provided on the upper surface of the sheet-like filler, and the bead core is positioned by the protrusion.

According to the present invention, since the protrusion is provided on the upper surface of the sheet-like filler to position the bead core, the position of the bead core can be fixed at the time of folding. Further, when the sheet-like filler is wound around the bead core, the bead core can be fixed and adhered to the periphery of the bead core so that no gap is formed between the bead core and the sheet-like filler.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a part of a pneumatic tire (tire size 205 / 65R15) 10 according to the present invention. The pneumatic tire 10 is provided with a carcass ply 12 formed in a toroidal shape, and a bead filler 20 is disposed between the main body 12A and the turnback portion 12B of the carcass ply 12. In the crown portion of the pneumatic tire 10, a belt 14 having a plurality of layers is arranged radially outside the carcass ply 12, and a tread 16 is arranged radially outside the belt 14.

The bead filler 20 is composed of a bead core 22 composed of a plurality of twisted steel cords, and a filler portion 24 formed of a single rubber or a composite rubber material such as fiber reinforced rubber. The bead filler 20 is a so-called S / H type bead filler 20 having an elongated cross section of a substantially triangular shape. The bead core 22 of the bead filler 20 is small, and the filler portion 24 is elongated. That is, the filler portion 24 extends toward the tread 16 while gradually reducing the thickness dimension, and reaches the center of the side portion of the pneumatic tire 10 along the carcass ply 12. At this time, the folded portion 12B of the carcass ply 12 is wound around the filler portion 24 around the bead core 22.

A side rubber 18 extending from the end of the tread 16 to the bead core 22 of the bead filler 20 is disposed outside the carcass ply 12 in the axial direction. The side rubber 18 is provided on the tread 1 from the bead core 22.
6 and the bead filler 20 with a substantially uniform thickness
Covering the surface.

Next, a method for forming the bead filler 20 will be described. FIG. 2 shows an example of a step of forming the bead filler 20.

The bead filler 20 mainly includes a filler sheet 26 constituting the filler portion 24 and the bead core 2.
2 is formed. The filler sheet 26 includes a pair of protrusions 28 separated by a predetermined distance at a central portion, and the thickness dimension of the filler sheet 26 gradually increases from the end of the filler sheet 26 toward each protrusion 28. ing. The bead core 22 is arranged between the pair of protrusions 28. The dimension from the portion where the bead core 22 is disposed to the end of the filler sheet 26 substantially corresponds to the dimension from the base to the tip of the bead filler 20.

When the bead core 22 is disposed at the center of the filler sheet 26, both ends of the filler sheet 26 are moved upward in FIG.
In the direction of arrow A in (A), the filler sheet 26 is folded and brought into close contact with both ends facing each other so as to wrap the pair of protrusions 28 using the bead core 22 as a core material. Thereby, the bead core 22 and the filler sheet 26 are integrated, and the S / H type bead filler 20 is formed.

Next, the tire molding machine 30 will be described. The pneumatic tire 10 is manufactured using a tire building machine 30 (see FIG. 3). As shown in FIG. 3 (A), the tire building machine 30 includes a diameter-enlarging drum 32 for expanding the diameter of a central portion of the carcass ply 12, and both end portions of the carcass ply 12. And a pair of inflatable bladders 34 for folding back (FIG. 3).
Then, only one inflatable bladder 34 is shown). Expanding drum 32
Is in the diameter-expanded state (see FIG. 3C), the surface of the diameter-expanding drum 32 is arranged at a position protruding from the surface of the expansion bladder 34. The diameter-expanding drum 32 is connected to diameter-expanding means and diameter-expanding control means (not shown) for moving the surface of the diameter-expanding drum 32 upward in FIG.

The inflatable bladder 34 includes an inflatable portion 36 which is hollow, and a bead support portion 38 which is provided at an end of the inflatable portion 36 on the side of the expanding drum 32. A filling means and a filling control mechanism (not shown) for filling the inside of the inflatable portion 36 with the filling material are connected. For example, air, steam, or the like is used as the filler.

Next, a method of manufacturing the pneumatic tire 10 will be described. FIG. 4 shows an example of a flow of a method of manufacturing the pneumatic tire 10. In addition, among the both ends of the carcass ply 12, one end will be mainly described.

In step 100, the expanding drum 32
After confirming that the diameter has been reduced, step 102
In, the carcass ply 12 is set so as to be wound around the peripheral surface of the diameter-enlarging drum 32 of the tire forming machine 30.
At this time, the folded portion 12B of the carcass ply 12 is arranged on the inflatable bladder 34 (see FIG. 3A).

Next, in step 104, the filler sheet 26 is set on the carcass ply 12. At this time, the protrusion 28 of the filler sheet 26 is directed upward, and the space between the pair of protrusions 28 is disposed on the bead support 38 of the inflatable bladder 34.

When the filler sheet 26 is disposed, the bead core 22 is further placed between the pair of protrusions 28 of the filler sheet 26 in step 106 (FIG. 3B).
reference). Thereby, the bead support portion 3 of the inflatable bladder 34
The bead core 22 is disposed on the upper surface 8.

When the bead core 22 is placed on the filler sheet 26, at step 108, the diameter expanding drum 3
2 is expanded (see FIG. 3C). As the diameter of the expanding drum 32 increases, the central portion of the carcass ply 12 expands upward in FIG. 3C (see arrow B). As the diameter of the carcass ply 12 increases, the end of the filler sheet 26 on the side of the expanding drum 32 moves upward together with the carcass ply 12 in FIG. The bead core 22 does not move because it is disposed on the bead support 38. For this reason, the filler sheet 26 is bent substantially at right angles together with the carcass ply 12 around the bead core 22 while the projection 28 on the side of the enlarged-diameter drum 32 is tightly wound around the bead core 22. Thereby, the filler sheet 2
The portion on the side of the enlarged-diameter drum 32 stands up along the enlarged-diameter drum 32.

When the diameter of the expanding drum 32 is expanded, in step 110, the inside of the expanding portion 36 of the expanding bladder 34 is filled with air to expand the expanding bladder 34 (FIG. 3).
(D)). When the inflatable bladder 34 starts to inflate, the surface of the inflatable portion 36 moves in the direction of arrow C in FIG. 3D, thereby the carcass ply 1 disposed on the inflatable portion 36.
2 and the end of the filler sheet 26 placed thereon are simultaneously folded back. At this time, the filler sheet 26 is moved to the bead core 2 by the movement of the surface of the expanding portion 36.
Since the filler sheet 26 is folded back together with the carcass ply 12 while being brought into close contact with the side closer to 2, the filler sheet 26 does not meander, but extends to the tip end. Further, since the carcass ply 12 and the filler sheet 26 are integrally moved, no gap is generated between the carcass ply 12 and the filler sheet 26. As a result, almost simultaneously with the folded portion 12B of the carcass ply 12 being folded, the filler sheet 26 is wound around the bead core 22 so that the ends thereof are overlapped, and the carcass ply 12
S / which is provided between the main body portion 12A and the folded portion 12B
The H-shaped bead filler 20 is formed.

After the carcass ply 12 is turned back and the bead filler 20 is formed, in step 112, the expansion of the inflatable bladder 34 is released, and then the side rubber 18 is arranged and brought into close contact with the surface of the bead filler 20 on the inflatable bladder 34 side. . The side rubber 18 covers the surface of the bead filler 20 with a substantially uniform thickness dimension, whereby a side portion of the pneumatic tire 10 is formed.

When the side rubbers 18 are arranged, in step 114, after the shape of the product tire is adjusted, tire components such as the belt 14, the tread 16 and the like are attached to predetermined positions to complete a raw tire.

As a result, with the operation of molding the pneumatic tire 10 in which the main body portion 12A of the carcass ply 12 is enlarged and the folded portion 12B is folded, the sheet-like filler sheet 26 is closely wound around the bead core 22 and wound. The S / H-type bead filler 20 standing along the carcass ply 12 and extending to the tip end can be formed.

Accordingly, the S / H type bead filler 20
The tip of the filler portion 24 does not bend or meander in contact with the carcass ply 12, the generation of air chambers can be prevented, and the S / H type can be efficiently formed without forming defects. The pneumatic tire 10 having the bead filler 20 can be manufactured.

In the present embodiment, the filler sheet 26
Has a pair of protrusions 28 at a substantially central portion of the upper surface.
The present invention is not limited to this as long as the / H type bead filler 20 can be formed.

For example, FIG. 5 shows another filler sheet 5.
0 is shown. The filler sheet 50 includes one protruding portion 56 that is slightly offset to the end side from the center, and a filler component 52 that has a long distance from the protruding portion 56 to the end.
And a winding portion 54 having a short distance from the protruding portion 56 to the end portion. The bead core 22 is disposed on the winding portion 54 close to the protrusion 56 of the filler sheet 50. Such a filler sheet 50 is wound around the carcass ply 12 such that the winding portion 54 is located on a portion of the carcass ply 12 on the side of the diameter increasing drum 32.

By moving both ends of the filler sheet 50 in the direction indicated by the arrow A in FIG.
An S / H type bead filler 58 is formed (FIG. 5B).
reference). At this time, since the thickness of the winding portion 54 is small, the winding portion 54 is wound more closely to the bead core 22.

By using such a bead filler 58, it is possible to obtain the pneumatic tire 10 including the S / H type bead filler 20 in which the bead core 22 and the filler portion 24 are more closely adhered.

In the embodiment of the present invention, one carcass ply 12 has been described as an example. However, even if a plurality of carcass plies 12 are used, the pneumatic tire 1
0 can be manufactured, and the same effect as described above can be obtained.

[0038]

As described above, according to the present invention, S
Since the / H type bead filler does not meander on the carcass ply, even if the S / H type bead filler is used, no air chamber is generated, and the occurrence of molding failure can be avoided. . As a result, a pneumatic tire including an S / H type bead filler can be efficiently manufactured without causing molding failure.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along an axis of a pneumatic tire according to an embodiment of the present invention.

FIG. 2A is a cross-sectional view of a filler sheet and a bead core according to an embodiment of the present invention, and FIG. 2B is a cross-sectional view of a bead filler formed from the filler sheet of FIG.

3A is a cross-sectional view of a tire molding machine on which a carcass ply is placed, FIG. 3B is a cross-sectional view of a tire molding machine in which a filler sheet and a bead core are arranged on the carcass ply of FIG. (C) is a cross-sectional view of the tire forming machine of (B) in which the diameter-expanding drum is expanded, and (D) is a cross-sectional view of the tire forming machine of (C) in which the inflatable bladder is expanded.

FIG. 4 is a flowchart illustrating an example of a method for manufacturing a pneumatic tire according to an embodiment of the present invention.

5A is a cross-sectional view of another filler sheet and a bead core according to the embodiment of the present invention, and FIG. 5B is a cross-sectional view of a bead filler formed from the filler sheet of FIG.

FIG. 6 is a sectional view taken along the axis of a conventional pneumatic tire.

7A is a cross-sectional view showing a state in which a bead filler according to the related art is attached to a carcass ply, and FIG. 7B is a cross-sectional view showing a state in which a central portion of the bead filler in FIG. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pneumatic tire 12 Carcass ply 16 Tread 18 Side rubber 20 Bead filler 22 Bead core 24 Filler part 26 Filler sheet 28 Projection part 30 Tire molding machine 32 Large diameter drum 34 Expansion bladder CL Center line

Claims (2)

[Claims] 1. A method of manufacturing a pneumatic tire using a tire molding machine having a diameter-enlarging drum that expands a central portion of a carcass ply and an inflatable bladder that turns both ends of the carcass ply. A sheet-like filler is laid on the carcass ply set on the drum and the inflatable bladder, and a bead core is further positioned at a predetermined position on the sheet-like filler. Manufacturing a pneumatic tire, wherein the sheet-like filler is bent so as to be wound around the bead core with an operation of folding an end portion, and an elongated bead filler is formed on a radial extension of the bead core. Method. 2. The method for manufacturing a pneumatic tire according to claim 1, wherein a protrusion is provided on an upper surface of the sheet-like filler, and the bead core is positioned by the protrusion.