JP2007015330A - Method of manufacturing pneumatic tire, and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a pneumatic tire by which a shaping time can be reduced through enhancing the efficiency in shaping work and the pneumatic tire. <P>SOLUTION: A stiffener has a separating structure constituted by adhering two stiffener rubbers 1, 4, first stiffener rubbers 1 are adhered to bead cores 2 in a state where the first stiffener rubber is inclined in a tire width direction from the final shape A. Both the end portions of a carcass ply 3 in a tire width direction are wound around the periphery of the bead cores 2 such that they are interposed between the first stiffener rubbers and the bead cores, the first stiffener rubbers 1 are erected from the inclined state by inflating the carcass ply 3 in a toroid shape while locking the bead cores 2, and further the second stiffener rubbers 4 are adhered to the first stiffener rubbers 1 to shape the stiffener. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for manufacturing a pneumatic tire and a pneumatic tire (hereinafter, also simply referred to as “manufacturing method” and “tire”), and more particularly, to a method for manufacturing a pneumatic tire according to an improvement in a bead portion molding process and thereby The present invention relates to a pneumatic tire to be obtained.

  Generally, in a pneumatic tire, a carcass ply forming a skeleton is extended from a tread portion to a bead portion through a sidewall portion in a toroid shape, and then folded back from the inside to the outside around a bead core embedded in each bead portion. It has a locked structure. In this case, the folded-back portion of the carcass ply is wound up along the outside of the stiffener arranged in the tire radial direction of the bead core, or is wound back and locked around the bead core.

  In the latter structure, since the end of the carcass ply is located between the bead core and the stiffener, the stiffener can be disposed in a state where the stiffener is previously attached to the bead core in the tire molding process. Disappear. On the other hand, for example, Patent Document 1 discloses a bead core having a stiffener attached thereto for the purpose of enabling pre-attachment of the stiffener to the bead core and preventing a reduction in the efficiency of molding the tire. Set inside the winding part of the carcass band with the stiffener lying posture, then stand up the stiffener in the lying posture on the outer circumference side of the winding part, and further join the belt and tread to the outer circumference side of the carcass band A tire manufacturing method is described.

Further, in Patent Document 2, in a bead with a stiffener including a ring-shaped bead and a substantially bowl-shaped stiffener, the side end of the carcass ply extends along the bead to the radially inner end of the stiffener. The bead with a stiffener that made it easy to manufacture a tire in which the side end portion of the carcass ply was wound around the bead and shortened the manufacturing time was used. A method for producing a green tire is described.
JP 2002-321289 A (Claims etc.) JP 2003-39922 A (Claims etc.)

  According to the techniques described in Patent Documents 1 and 2, it is possible to easily manufacture a tire having a structure in which a ply is wound around a bead core using a bead core to which a stiffener is attached in advance. In terms of sticking between the bead core and the stiffener, the molding work efficiency can be improved.

  However, in this case, as shown in FIGS. 3A to 3C, the stiffener 11 ((a) in the figure) attached to the bead core 12 is once tilted by the roll 21 and the ply 13 is moved around the bead core 12. Then, a step of rewinding ((b) in the figure) and then bringing it back up by the roll 22 ((c) in the figure) is required. Therefore, it is necessary to provide dedicated rolls 21 and 22, the molding time increases due to the operation time of these rolls 21 and 22, and maintenance such as malfunction of rolls 21 and 22 is required. However, there was a problem that the efficiency of the molding work was impaired.

  Therefore, the purpose of the present invention is to improve the molding work efficiency when manufacturing a pneumatic tire having a bead portion structure in which the carcass ply is wound around the bead core using the bead core to which the stiffener is attached in advance. It is an object of the present invention to provide a method for manufacturing a pneumatic tire capable of reducing the molding time and a pneumatic tire obtained thereby.

  As a result of intensive studies, the present inventor has found that the following configuration can further improve the molding work efficiency as compared with the prior art, and has completed the present invention.

That is, the method for manufacturing a pneumatic tire according to the present invention includes a bead core embedded in a pair of bead portions, and a stiffener disposed on the outer side in the tire radial direction of the bead core, and straddles between the pair of bead cores. In the method of manufacturing a pneumatic tire comprising a carcass ply that is formed in a toroid shape and whose both ends are wound around the bead core from the inside to the outside in the tire width direction and locked.
The stiffener has a divided structure formed by bonding two stiffener rubbers,
Of the two stiffener rubbers, the first stiffener rubber on the side in contact with the bead core is attached to the bead core in a state inclined in the tire width direction from the final shape, and the bead core to which the first stiffener rubber is attached is attached. Around the periphery, both ends of the carcass ply in the tire width direction are wound so as to be interposed between the first stiffener rubber and the bead core, and then the carcass ply is expanded in a toroidal shape while locking the bead core. One stiffener rubber is raised from an inclined state to a final shape, and the remaining second stiffener rubber is bonded to the first stiffener rubber to form the stiffener. The volume of the first stiffener rubber may be in the range of 20-50% of the stiffener.

  The pneumatic tire of the present invention is manufactured by the method for manufacturing a pneumatic tire of the present invention.

  In the tire of the present invention, even if the first stiffener rubber and the second stiffener rubber are made of the same rubber composition, the first stiffener rubber and the second stiffener rubber are made of different rubber compositions. In addition, the first stiffener rubber may be higher in hardness than the second stiffener rubber.

  According to the method for manufacturing a pneumatic tire of the present invention, the above configuration eliminates the need for a dedicated roll, which is necessary in the conventional method, and can shorten the molding time. In addition, since the rolls are eliminated, malfunction prevention and maintenance are unnecessary, and as a result, it is possible to further improve the molding work efficiency. Moreover, in the pneumatic tire of this invention obtained by this, since a stiffener has a division structure, it also has the merit that it can adjust hardness suitably according to desired bead part rigidity.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
The method for manufacturing a pneumatic tire of the present invention is a method for manufacturing a pneumatic tire having a structure in which a carcass ply is wound around and locked around a bead core using a bead core to which a stiffener is previously attached. This is a technique related to the improvement of the bead part molding process.

  In FIG. 1, the flow of the shaping | molding process in the manufacturing method of the pneumatic tire of this invention is shown. In the present invention, the stiffener is formed as a divided structure formed by bonding two stiffener rubbers 1 and 4 (see FIG. 2). First, as shown in FIG. The first stiffener rubber 1 on the contact side is adhered to the bead core 2 in a state inclined from the final shape A in the tire width direction.

  As the stiffener is divided into two stiffener rubbers 1 and 4, the first stiffener rubber 1 to be attached to the bead core 2 is formed small so that the opening between the bead core and the stiffener can be reliably held. The carcass ply 3 can be easily wound between the bead core and the stiffener. In addition, by sticking the first stiffener rubber 1 to the bead core 2 in a state of being inclined in the tire width direction from the final shape A from the beginning, there is no need to separately provide a roll for inclining as in the prior art. It is possible to prevent the increase, shorten the molding time, and eliminate problems such as malfunction and occurrence of maintenance.

  Here, the volume of the first stiffener rubber 1 is not particularly limited, but can be, for example, in the range of 20 to 50% of the stiffener. If the volume of the first stiffener rubber 1 is too small, it becomes difficult to mold the stiffener and the volume of the second stiffener rubber is too large to be folded back. On the other hand, if the volume is too large, the bead core-stiffener gap is maintained. This makes it difficult to wind the carcass ply 3, which is not preferable.

  Next, as shown in FIG. 1B, both ends of the carcass ply 3 in the tire width direction are interposed between the first stiffener rubber and the bead core around the bead core 2 to which the first stiffener rubber 1 is adhered. Wrap around. The winding method of the carcass ply 3 at this time may follow a conventional method and is not particularly limited.

  Next, as shown in FIG. 1C, the carcass ply 3 is expanded in a toroidal shape with the bead core 2 locked, and the first stiffener rubber 1 is raised from the inclined state to the final shape A. Since the first stiffener rubber 1 can be raised to the position of the final shape A by the inflation of the green case, it is not necessary to provide a separate roll even in this process, preventing an increase in the process and shortening the molding time. As well as problems such as malfunctions and maintenance.

  Further, as shown in FIG. 1D, the desired second stiffener rubber 4 can be formed by bonding the remaining second stiffener rubber 4 to the first stiffener rubber 1 (FIG. 1 ( e)). When the second stiffener rubber is affixed, it may be affixed alone or in combination with a side rubber or the like. Further, the attaching method is not particularly limited. The first stiffener rubber 1 and the second stiffener rubber 4 may be made of the same rubber composition, but may be made of different rubber compositions. In this case, for example, the first stiffener rubber 1 However, it is possible to adjust the bead portion rigidity appropriately as the hardness is higher than that of the second stiffener rubber 4.

  The pneumatic tire of the present invention has a bead core 2 embedded in each of a pair of bead portions, and a stiffener disposed on the outer side in the tire radial direction, and has a toroidal shape straddling the pair of bead cores 2. None, provided with the carcass ply 3 whose both ends are wound around the bead core 2 from the inner side to the outer side in the tire width direction and locked, and manufactured by the pneumatic tire manufacturing method of the present invention. Any other specific structure, material, etc. are not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Conventional example)
Tire size: 495 / 45R22.5 (wind structure), and a pneumatic tire having a structure in which a carcass ply is wound around a bead core is obtained by a method using dedicated rolls 21 and 22 shown in FIG. It was produced by molding the bead part.

(Example)
Example tires were produced in the same manner as in the conventional example except that the bead portion was molded by a method not using the roll shown in FIG. The stiffener has a split structure in which two stiffener rubbers are bonded together. The first stiffener rubber 1 on the side in contact with the bead core has a cross-sectional shape shown in FIG. 4, and the second stiffener rubber 4 has a cross-sectional shape shown in FIG. . Moreover, the shaping leg width (member folding width) at the time of inflation of the green case was set to bead lock width-340 mm (total width).

  Specifically, first, the first stiffener rubber 1 is attached to the bead core 2 in a state inclined in the tire width direction (FIG. 1A), and the bead core 2 to which the first stiffener rubber 1 is attached is attached. Around the periphery, both ends of the carcass ply 3 in the tire width direction were wound so as to be interposed between the first stiffener rubber and the bead core (FIG. 1B). Next, the first stiffener rubber 1 is raised from the inclined state by inflating the carcass ply 3 in a toroidal shape while locking the bead core 2 (FIG. 1C), and the remaining second stiffener rubber 4 is changed to the first stiffener rubber 1. By bonding (FIG. 1 (d)), a stiffener was formed as shown in FIG. 1 (e).

  As a result, in the method of the example, it was confirmed that the molding time can be shortened by 30 seconds compared with the conventional example, and the molding work efficiency can be improved by the method of the example.

(A)-(e) is explanatory drawing which shows the bead part shaping | molding process in the manufacturing method of the pneumatic tire which concerns on one embodiment of this invention. It is a fragmentary sectional view showing the bead part structure of the pneumatic tire concerning one embodiment of the present invention. (A)-(c) is explanatory drawing which shows the bead part shaping | molding process in the manufacturing method of the conventional pneumatic tire. It is the schematic which shows the cross-sectional shape of the 1st stiffener rubber used in the Example. It is the schematic which shows the cross-sectional shape of the 2nd stiffener rubber used in the Example.

Explanation of symbols

1 First stiffener rubber 2, 12 Bead core 3, 13 Carcass ply 4 Second stiffener rubber 11 Stiffener 21, 22 Roll

Claims (5)

Each of the pair of bead portions has a bead core embedded therein and a stiffener disposed on the outer side of the bead core in the tire radial direction. The bead core has a toroid shape between the pair of bead cores. In the manufacturing method of a pneumatic tire provided with a carcass ply that is wound and wound around from the inside in the tire width direction toward the outside,
The stiffener has a divided structure formed by bonding two stiffener rubbers,
Of the two stiffener rubbers, the first stiffener rubber on the side in contact with the bead core is attached to the bead core in a state inclined in the tire width direction from the final shape, and the bead core to which the first stiffener rubber is attached is attached. Around the periphery, both ends of the carcass ply in the tire width direction are wound so as to be interposed between the first stiffener rubber and the bead core, and then the carcass ply is expanded in a toroidal shape while locking the bead core. A method for producing a pneumatic tire, comprising: raising one stiffener rubber from an inclined state to a final shape, and bonding the remaining second stiffener rubber to the first stiffener rubber to form the stiffener.   The method for manufacturing a pneumatic tire according to claim 1, wherein a volume of the first stiffener rubber is set in a range of 20 to 50% of the stiffener.   A pneumatic tire manufactured by the method for manufacturing a pneumatic tire according to claim 1 or 2.   The pneumatic tire according to claim 3, wherein the first stiffener rubber and the second stiffener rubber are made of the same rubber composition.   The pneumatic tire according to claim 3, wherein the first stiffener rubber and the second stiffener rubber are made of different rubber compositions, and the first stiffener rubber has higher hardness than the second stiffener rubber.

Images