JP2007326288A - Method for molding green tire and method for manufacturing pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit the trapping of air between an inner liner and a carcass ply, enhance the efficiency of a green tire molding operation and enable the inner liner to be made thin-walled. <P>SOLUTION: Prior to the winding of the inner liner 3 around a molding drum 1, the inner liner 3 is previously laminated with at least the carcass ply 5 into one piece, and thereby, a composite member 10 made up of a plurality of tire constituent members, is formed. Then the composite member 10 is wound around the outer periphery of the rotating molding drum 1, and the green tire is molded by laminating together other tire constituent members such as a pair of flippers 6, a bead core 7 having a bead filler 8 and a belt 9 or any other means. Finally, the green tire is vulcanization-molded and thus, a pneumatic tire of a specified shape is obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a green tire (raw tire) molding method and a pneumatic tire manufacturing method, and more particularly to a green tire molding method and a pneumatic tire manufacturing method with improved productivity in a green tire molding process.

  A pneumatic tire is generally composed of a plurality of tire constituent members made of various unvulcanized rubbers, cords, etc., and after molding a green tire with each of these tire constituent members, it is put into a mold of a vulcanization molding machine. A predetermined shape is formed by heating (vulcanization molding) for a predetermined time at a predetermined temperature and pressure. In this green tire molding process, conventionally, unvulcanized rubber is extruded using an extruder, etc., and each tire component having a predetermined shape is manufactured, and these are combined and molded on a substantially cylindrical molding drum. Is widely adopted (see Patent Document 1).

Although FIG. 2 is not described in the patent document, it is a schematic diagram for explaining a general procedure for combining tire constituent members when a green tire is molded in this manner. A molding drum 1 is a drum. In the side view seen from radial direction, each tire structural member is shown with sectional drawing seen from the same direction.
The molding drum 1 is rotated around an axis by driving means (not shown), and each tire constituent member is wound around and bonded to the outer periphery, and the center portion of the bonded tire constituent members is swelled in a substantially toroidal shape. Well-known means and structure of a general molding drum are provided, such as means for letting out or means for turning back an end of a tire constituent member such as a carcass ply (not shown).

  When a green tire is molded using the molding drum 1, generally, as shown in the figure, first, a pair of left and right canvas chafers 2 arranged on the outer surface of the tire bead portion on the outer periphery of the rotating molding drum 1, A substantially sheet-like inner liner 3 for winding the tire inner surface to maintain airtightness is wound. Next, the substantially sheet-like carcass ply 5 with the squeegee rubber 4 attached to the outer periphery of the inner liner 3 is wound around the squeegee rubber 4 toward the molding drum 1 side (lower side in the figure), and bonded together. A shaped molded body is formed. A pair of substantially annular bead cores 7 having a flipper 6 that covers and reinforces the periphery of each of the pair of bead cores 7 and the like, and a bead filler 8 that tapers outwardly in the drum radial direction (upper side in the drawing) on its outer peripheral side. Are sequentially arranged at predetermined positions.

  Next, both ends of the carcass ply 5 and the like wound around the molding drum 1 are folded around the bead core 7 and the bead filler 8 from the outer side to the inner side in the drum axial direction (left and right direction in the figure), and the tire on the molding drum 1 The center of the constituent members (inner liner 3, carcass ply 5, etc.) is bulged in a substantially toroidal shape. Thereafter, the belt 9 is bonded to the outer periphery of the bulged carcass ply 5, and a tread or sidewall (not shown) constituting the outer surface of the tire is formed on the outer side thereof, and other tire constituent members are combined to form a predetermined shape. A green tire is molded.

  Here, in recent years, the inner liner 3 has extremely high air permeation resistance due to technological advances, and even if it is made thinner, the air tightness of the tire equivalent to the conventional tire can be ensured. However, when the inner liner 3 is made thinner than its current state, its strength, rigidity, and the like are also reduced, so local elongation and wrinkles are generated in the inner liner 3 when it is wound around the molding drum 1. Or various problems such as difficulty in handling and reduced workability. Therefore, in the above-described conventional molding method, it is necessary to form the inner liner 3 with a thickness greater than necessary, that is, to ensure workability by making it thicker than necessary to ensure airtightness, There is a problem that it is difficult to reduce the weight of the tire because it cannot be made thinner than the present situation.

  Further, in this conventional molding method, after the inner liner 3 is wound on the molding drum 1 in a substantially cylindrical shape so as not to cause wrinkles, the carcass ply 5 is prevented from being displaced on the curved outer periphery. However, there is also a problem that the molding work is extremely complicated, the workability and work efficiency are low, and the tire productivity is low, such as the need to bond them in a substantially cylindrical shape. Further, in addition to the complexity of this work, the inner liner 3 and the carcass ply 5 have a large contact area, so that air easily enters between them. There is also a risk of defects in the tire.

JP 2005-305753 A

  The present invention has been made in view of the above-described conventional problems, and its purpose is to suppress the occurrence of air entering between the inner liner and the carcass ply and to improve the working efficiency of the green tire molding operation. In addition, it is possible to reduce the thickness of the inner liner, reduce the weight and improve the productivity of the pneumatic tire, and reduce the manufacturing cost.

The invention of claim 1 is a green tire molding method in which a plurality of tire constituent members including an inner liner and a carcass ply are combined to form a green tire, and the inner liner and at least the carcass ply are bonded together. And forming a composite member composed of two or more tire constituent members including the inner liner and the carcass ply, and winding the composite member around an outer periphery of a molding drum.
Invention of Claim 2 is a manufacturing method of a pneumatic tire, Comprising: The green tire shape | molded by the method as described in Claim 1 is vulcanized-molded, and a pneumatic tire is manufactured.

  According to the present invention, it is possible to prevent air from entering between the inner liner and the carcass ply, and to improve the working efficiency of the green tire molding operation. Further, the inner liner can be thinned, the weight of the pneumatic tire can be reduced and the productivity can be improved, and the manufacturing cost can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The pneumatic tire manufacturing method of the present embodiment is a method for manufacturing a pneumatic tire formed by vulcanizing and molding a green tire such as a radial tire for passenger cars, for example, and the conventional molding method shown in FIG. Similarly, a green tire is molded by combining a plurality of unvulcanized tire constituent members. However, the green tire molding method of the present manufacturing method is different from the conventional molding method in that the green tire is molded by winding the inner liner and at least the carcass ply in advance and then winding them around a molding drum.

FIG. 1 is a schematic view for explaining a molding procedure of a green tire according to the present embodiment. A molding drum 1 is a side view seen from the drum radial direction, and each tire constituent member is a sectional view seen from the same direction. Show.
Since the molding drum 1 and each tire constituent member are the same as the above-described molding drum 1 and each tire constituent member shown in FIG. 2, the description thereof is omitted here.

  In the present embodiment, as illustrated, the inner liner 3, the carcass ply 5, and the pair of canvas chafers 2 are bonded together and integrated to form a composite member 10 composed of a plurality of tire constituent members. The composite member 10 cuts a member made of unvulcanized rubber or the like molded into a predetermined cross-sectional shape by an extruder, a calendar device or the like to form each member 3, 5, 2 into a predetermined shape, The members 3, 5 and 2 before being cut are bonded and integrated together by pressing them with a roller or the like while being arranged at the position, or after being bonded and integrated in the same manner and then formed into a predetermined shape.

  Here, the inner liner 3 is disposed at the approximate center in the width direction of the carcass ply 5 (the left-right direction in the figure), and a pair of canvas chafers 2 are disposed so as to partially overlap both ends of the inner liner 3 in the width direction. Thus, the composite member 10 is formed. Further, since the inner liner 3 and the carcass ply 5 are integrated in advance, it is not necessary to provide the squeegee rubber 4 (see FIG. 2) between them and is omitted.

  When molding the green tire, first, the composite member 10 is wound around the outer periphery of the rotating molding drum 1, and the inner liner 2 side is wound toward the molding drum 1 side (the lower side in the drawing) to form a substantially cylindrical shape. On the outer peripheral side, a bead core 7 having a pair of flippers 6 and a bead filler 8 is sequentially arranged at a predetermined position. Next, both end portions of the composite member 10 are folded back around the bead core 7 and the bead filler 8 from the outside in the drum axial direction (left-right direction in the drawing) from the outside to the inside, and the center of the composite member 10 is expanded in a substantially toroidal shape.

  Next, after the belt 9 is bonded to the outer periphery of the swelled composite member 10, a tread or sidewall (not shown) constituting the outer surface of the tire is formed on the outside thereof, and other tire constituent members are combined. A green tire having a predetermined shape is molded. Thereafter, the green tire is removed from the molding drum 1 and conveyed to a vulcanization molding apparatus in the next process, inserted into a vulcanization mold and vulcanized to produce a pneumatic tire having a predetermined shape.

  As described above, according to the green tire molding method and the pneumatic tire manufacturing method of the present embodiment, the inner liner 3 is bonded and integrated in advance with the carcass ply 5 and the like. Compared to the above-described conventional molding method (see FIG. 2) that is combined one by one, the inner liner 3 can be handled easily, the green tire molding operation can be simplified, and workability and work efficiency can be improved. Can do. At the same time, the inner liner 3 and the carcass ply 5 are bonded on the flat conveyor, for example, instead of on the substantially cylindrical molding drum 1, so that the bonding operation can be performed easily and reliably. Accordingly, it is possible to suppress the entry of air between the members that are likely to occur at the time of bonding, the occurrence of wrinkles and elongation of the inner liner 3 at the time of winding, and the occurrence of defects in the green tire and the product tire.

  For example, in a general passenger car tire, it takes about 25 DM (1 DM is 0.6 seconds) when winding the inner liner 3 around the molding drum 1. Therefore, the cycle time of green tire molding can be shortened accordingly. Furthermore, since it is not necessary to store the inner liner 3 alone, the inventory space required for the storage can be reduced.

  In addition, since the inner liner 3 is transported and wound as the composite member 10 together with the carcass ply 5 and the like, even if it is made thinner and the strength, rigidity, etc. are reduced, elongation or wrinkle occurs, or The various problems described above, such as difficulty in handling and reduced workability, are less likely to occur. Therefore, the inner liner 3 can be formed to a thickness necessary for ensuring airtightness and the like, and can be made thinner than the current state. At the same time, as described above, the squeegee rubber between the layers is also unnecessary, so that the amount of rubber used can be reduced and the weight of the tire can be reduced, and the above-mentioned green tire molding work efficiency can be improved and the cycle time can be shortened. As a result, the productivity of the tire can be improved, and the manufacturing cost of the pneumatic tire can be reduced.

  In this embodiment, the inner liner 3 is integrated with the carcass ply 5 and the canvas chafer 2 to form the composite member 10. However, in order to obtain the above-described effects, the inner liner 3 is at least the carcass ply 5. And the composite member 10 may be formed. Therefore, the canvas chafer 2 may be wound around the molding drum 1 separately from the composite member 10, and conversely, other tire constituent members such as the flipper 6 are further bonded to the composite member 10. The member 10 may be formed from a larger number of tire constituent members including the inner liner 3 and the carcass ply 5.

  Further, in the above-described green tire molding, the case where the composite member 10 is bulged in a toroidal shape on the single molding drum 1 has been described as an example. After combining with No. 7, etc., it may be performed by other methods such as removing from the molding drum 1 and placing it on another drum to bulge out.

It is a schematic diagram for demonstrating the formation procedure of the green tire of this embodiment. It is a schematic diagram for demonstrating the combination procedure of the general tire structural member at the time of shape | molding the conventional green tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Molding drum, 2 ... Canvas chafer, 3 ... Inner liner, 4 ... Squeegee rubber, 5 ... Carcass ply, 6 ... Flipper, 7 ... Bead core, 8 ... -Bead filler, 9 ... belt, 10 ... composite member.

Claims (2)

A green tire molding method for molding a green tire by combining a plurality of tire constituent members including an inner liner and a carcass ply,
Bonding and integrating the inner liner and at least the carcass ply to form a composite member composed of two or more tire components including the inner liner and the carcass ply;
Winding the composite member around an outer periphery of a molding drum;
A method for molding a green tire, comprising:   A pneumatic tire is manufactured by vulcanizing and molding a green tire molded by the method according to claim 1.

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