JP2005066868A - Method for molding and assembling pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding and assembling a pneumatic tire not causing a buckling phenomenon or a crack in the surface of a bead member, capable of being adapted even to the specifications of the thin-walled lightweight structure around the bead member and capable of molding the pneumatic tire of high quality. <P>SOLUTION: At least one or above annular notched grooves 9a, 9b and 9c are formed to the outer peripheral surface of a bead filler 11 and, when the bead filler 11 is folded back to the inside of the tire, the annular notched grooves 9a, 9b and 9c are opened to reduce the internal stress of the bead filler 11 and, when the bead filler 11 is folded back to the outside at the time of vulcanizing molding, the annular notched grooves 9a, 9b and 9c are closed to prevent not only the occurrence of compression force Fa in the outside surface of the bead filler 11 but also the occurrence of the buckling phenomenon or the crack in the surface of the bead member 10. Further, this molding and assembling method of the pneumatic tire can be adapted even to the specifications of the thin-walled lightweight structure around the bead member and the tire of high quality can be molded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for molding and assembling a pneumatic tire, and more particularly, a pneumatic tire capable of producing a high-quality tire by preventing buckling or cracking around a bead member when molding and assembling a heavy duty tire. The present invention relates to a method for molding and assembling a tire.
[0002]
[Prior art]
Conventionally, as shown in FIG. 3, a pneumatic tire is molded by winding a carcass member 2 around a molding drum 1 in a cylindrical shape, and bead fillers 3 on the outer peripheral surfaces of both side edges of the carcass member 2. After mounting the bead member 5 formed in an annular shape on the outer peripheral surface, the bead filler 3 was folded back inside the tire through the bladder 6, and a side rubber member 7 and a cap member 8 were sequentially laminated on both sides of the outer periphery. Thereafter, the tire is inflated and vulcanized and molded in a vulcanization step.
[0003]
As a conventional heavy duty pneumatic tire molding method, a three-stage molding method is known which includes a band molding process, a first molding process (first stage molding process), and a second molding process (second stage molding process).
[0004]
However, in the three-stage molding method as described above, since the bead member is assembled in the first molding process, a tensile force and a compressive force are generated inside and outside the bead member during the second molding process. That is, as shown in FIG. 4, when the bead filler 3 is folded inside the forming drum 1 through the bladder 6, a compressive force Fa acts on the inner surface side of the bead filler 3, and on the outer surface. A tensile force Fb acts.
[0005]
Further, in the vulcanization process, the bead filler 3 is deformed to the outside again, so that a compressive force Fa is generated on the outer surface of the bead filler 3 and a tensile force Fb is generated on the inner surface side, and rubber during vulcanization is generated. There is a problem that a buckling phenomenon, a crack or the like is likely to occur on the surface of the bead filler 3 from the flow.
[0006]
In addition, when the inside of the bead filler is folded back, the internal stress of the folded bead filler prevents the thickness (gauge) of the side rubber member during vulcanization from becoming unstable. An invention has been proposed in which a plurality of cut portions are provided (see, for example, Patent Document 1).
[0007]
[Patent Document 1]
JP-A-5-200907 (pages 2 to 3 and FIG. 1)
[0008]
[Problems to be solved by the invention]
However, in the case where a plurality of cuts are provided on the inner circumference of the bead filler, when the bead filler is folded inside the tire, the internal stress can be reduced by the cut part, but on the outside during vulcanization molding. When folded, a compressive force is generated on the outer surface of the bead filler, and there is a problem that a buckling phenomenon, a crack or the like is likely to occur on the surface of the bead member of the tire as the final product.
[0009]
The present invention pays attention to such a conventional problem, and even with a three-stage molding method, it is possible to obtain a state around the bead similar to the case of inflation molding, and the bead member has a buckling phenomenon, a crack or the like on the surface. An object of the present invention is to provide a method for forming and assembling a pneumatic tire that can be applied to the specification of a thin and light structure around a bead member without being generated, and can form a high-quality tire.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a bead filler comprising a bead filler in which a carcass member is wound around a molding drum in a cylindrical shape, and at least one annular notch groove is formed on an outer peripheral surface at both side edges of the carcass member. After mounting a bead member that is wound in an annular shape on the outer peripheral surface, the bead filler of the bead member is folded back inside the forming drum along the annular notch ring groove, and a release sheet is interposed on both sides of the outer periphery After laminating the side rubber members respectively, the carcass member is expanded, and both side edge portions are folded back to the outside of the bead members, respectively, the release sheet is removed, and the side rubber members are laminated on the bead members, Further, the gist is to vulcanize and mold a tire in a vulcanization step after laminating a cap member at the center of the carcass member.
[0011]
Here, at least one or more annular notch grooves formed on the outer peripheral surface of the bead filler are processed at the time of extrusion molding of the bead filler or after the molding of the bead filler, and the annular notch groove is a base end of the bead filler. A plurality of annular cutout grooves whose depth of cut is gradually reduced from the portion toward the tip portion are provided.
[0012]
In this way, by forming at least one annular notch groove on the outer peripheral surface of the bead filler, when the bead filler is folded back inside the tire, the annular notch groove opens and the internal stress of the bead filler is reduced. When turning back outward during vulcanization molding, closing the annular notch groove does not generate compressive force on the outer surface of the bead filler, but buckles or cracks on the surface of the bead member Can be applied to the specification of a thin and light structure around the bead member, and a high-quality tire can be molded.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0014]
In the following description, the same components as those in the conventional example are denoted by the same reference numerals, and the description thereof is omitted.
[0015]
FIG. 1 is an assembly explanatory diagram of a molding drum end portion for carrying out the method for molding and assembling a pneumatic tire according to the present invention, wherein 1 is a molding drum in a first molding process, and 2 is a cylinder wound around the molding drum. An annular notch groove which is a carcass member and has at least one (not limited to three in this embodiment) on the outer peripheral surface as shown in FIG. 2 on both side edges of the carcass member 2 An annular bead member 10 formed with 9a, 9b, 9c is mounted.
[0016]
In addition, the carcass member 2 in this embodiment generically refers to a carcass layer, an inner liner, a steel or organic fiber reinforcing layer, a rubber sheet, and the like.
[0017]
The bead member 10 is constructed by annularly winding the bead filler 11 having the above-described annular notch grooves 9a, 9b, 9c around the outer peripheral surface of the bead core 12, and the annular notch grooves 9a, 9b, 9c The depth of cut gradually decreases from the proximal end portion 11a of the filler 11 toward the distal end portion 11b.
[0018]
And in embodiment of this invention, after mounting the bead member 10 to the both-sides edge part of the said carcass member 2, the bead filler 11 of the said bead member 10 is made into inner side of a tire along the annular notch ring groove 9a, 9b, 9c. The side rubber members 13 are laminated in a state where the release sheets 12 are interposed on both sides of the outer periphery.
[0019]
Thereafter, the carcass member 2 is expanded and both side edges thereof are folded back to the outside of the bead member 10, the release sheet 12 is removed, the side rubber member 13 is laminated on the bead member 10, and the carcass member After laminating the cap member 14 at the center of the tire 2, the tire is vulcanized in the vulcanization process.
[0020]
Note that the cap member 14 in this embodiment is a generic term for a belt layer, a reinforcing layer, an undertread, a cap tread, and the like.
[0021]
In the present invention, at least one or more annular notch grooves 9a, 9b, 9c are formed on the outer peripheral surface of the bead filler 11, so that when the bead filler 11 is folded back inside the tire, the annular notch grooves 9a, 9b, 9c can be opened to reduce the internal stress of the bead filler 11, and when turning outward during vulcanization molding, the annular notch grooves 9a, 9b, 9c can be closed to the outer surface of the bead filler 11. Does not generate compressive force Fa, can prevent the occurrence of buckling phenomenon and cracks on the surface of the bead member 10, and can be applied to the specification of a thin and light structure around the bead to form a high-quality tire. It is possible.
[0022]
Further, since the side rubber members 13 are laminated in a state where the release sheet 12 is interposed, the side rubber member 13 can be formed into a so-called side-over structure in which the side rubber members 13 are assembled after the second step is inflated.
[0023]
As described above, in the embodiment of the present invention, the annular notch grooves 9a, 9b, and 9c are formed on the outer peripheral surface of the bead filler 11, so that when the bead filler 11 is folded back inside the tire, the annular notch The grooves 9a, 9b, 9c can be opened to reduce the internal stress of the bead filler 11, and when turning back outward during vulcanization molding, the annular notch grooves 9a, 9b, 9c can be closed to close the bead filler 11. Compressive force Fa is not generated on the outer surface, buckling phenomenon and cracks are prevented from occurring on the surface of the bead member 10, and it can be applied to the specification of a thin and light structure around the bead member to form a high-quality tire. It can be done.
[0024]
【The invention's effect】
In the present invention, a carcass member is wound around a molding drum in a cylindrical shape as described above, and a bead filler having at least one annular notch groove formed on the outer peripheral surface at both side edges of the carcass member is provided on the outer peripheral surface of the bead core. After mounting the bead member formed in a ring shape, the bead filler of the bead member is folded back inside the forming drum along the annular notch ring groove, and the release rubber is interposed on both sides of the outer periphery of the side rubber. After laminating the members, the carcass member is expanded, both side edges thereof are folded back to the outside of the bead member, the release sheet is removed, the side rubber member is laminated on the bead member, and the carcass is further laminated. After laminating the cap member in the center of the member, the tire is vulcanized in the vulcanization process, so when folding the bead filler inside the tire, The notch groove can be opened to reduce the internal stress of the bead filler, and when turning back to the outside during vulcanization molding, closing the annular notch groove does not generate compressive force on the outer surface of the bead filler, This prevents the occurrence of buckling and cracks on the surface of the bead member, and can be applied to the specification of a thin and light structure around the bead member, thereby producing an effect of molding a high-quality tire.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an assembly explanatory view of a forming drum end for carrying out a method for forming and assembling a pneumatic tire according to the present invention.
FIG. 2 is an explanatory view showing a deformed state of a bead filler during molding and assembling of the pneumatic tire of the present invention.
FIG. 3 is an assembly explanatory diagram of a forming drum end for carrying out a conventional method for forming and assembling a pneumatic tire.
FIG. 4 is an explanatory view showing a deformation state of a bead filler at the time of molding and assembling a conventional pneumatic tire.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molding drum 2 Carcass member 3 Bead filler 4 Bead core 5 Bead member 6 Bladder 7 Side rubber member 8 Cap member Fa Compression force Fb Tensile force 9a, 9b, 9c Annular notch groove 10 Bead member 11 Bead filler 11a Base end part 11b Tip part 12 Release sheet 13 Side rubber member 14 Cap member

Claims (3)

A bead formed by winding a carcass member around a molding drum in a cylindrical shape and annularly winding a bead filler having at least one annular notch groove on the outer peripheral surface at both side edges of the carcass member around the outer peripheral surface of the bead core. After mounting the member, the bead filler of the bead member is folded back inside the molding drum along the annular notch ring groove, and after laminating the side rubber members with the release sheets interposed on both sides of the outer periphery, The carcass member is expanded, and both side edges thereof are folded back to the outside of the bead member, then the release sheet is removed, the side rubber member is laminated on the bead member, and the cap member is further laminated at the center of the carcass member. Thereafter, a pneumatic tire molding and assembling method in which a tire is vulcanized and molded in a vulcanization process. 2. The pneumatic tire molding and assembling method according to claim 1, wherein at least one or more annular cutout grooves formed on the outer peripheral surface of the bead filler are processed during extrusion molding of the bead filler or after molding of the bead filler. 3. The method for molding and assembling a pneumatic tire according to claim 1, wherein the annular notch groove includes a plurality of annular notch grooves whose depth of cut gradually decreases from a base end portion to a tip end portion of the bead filler.

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