JP2020111179A - Pneumatic bias tire and manufacturing method of pneumatic bias tire - Google Patents

Abstract

To provide a pneumatic bias tire and a manufacturing method of the pneumatic bias tire in which a rubber chafer can be arranged around a bead core.SOLUTION: A pneumatic bias tire includes a rubber chafer 3 which is folded around a bead part 1 so as to wrap the bead part 1 from an outer side of a carcass layer 2, and the carcass layer 2 includes a plurality of bias plies 2a, 2b, 2c having a carcass cord inclining with respect to a tire circumferential direction. An adhesion rubber part 6 formed by vulcanizing unvulcanized rubber containing a tackifier is arranged so as to cover at least a part of both surfaces of the rubber chafer 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pneumatic bias tire and a method for manufacturing a pneumatic bias tire.

As a pneumatic tire, a pneumatic bias tire including a carcass ply having a bias structure that is bridged in a toroidal shape between a pair of left and right bead portions is known (for example, refer to Patent Document 1 below).

In such a pneumatic bias tire, when vulcanizing and molding an unvulcanized green tire, rubber around the bead portion easily flows to the sidewall, so a rubber member called a rubber chafer is arranged around the bead portion. Can be difficult.

JP, 2005-209040, A

In view of the above points, an object of the present invention is to provide a pneumatic bias tire in which a rubber chafer can be arranged around a bead core, and a method for manufacturing a pneumatic bias tire.

The pneumatic bias tire of the present invention includes a bead portion, a carcass layer folded back around the bead portion so as to wind the bead portion, and the bead portion so as to wind the bead portion from the outside of the carcass layer. In a pneumatic bias tire including a plurality of bias plies having a carcass cord inclined with respect to the tire circumferential direction, the carcass layer having a rubber chafer folded back around, and an unadded tackifier. An adhesive rubber part obtained by vulcanizing a vulcanized rubber is provided so as to cover at least a part of both surfaces of the rubber chafer.

The method for manufacturing a pneumatic bias tire according to the present invention includes a bead portion, a carcass layer folded back around the bead portion so as to wind the bead portion, and the bead portion is wound from the outside of the carcass layer. A pneumatic bias tire comprising a rubber chafer folded back around a bead portion, wherein the carcass layer is vulcanized and molded into a green tire having a plurality of bias plies having carcass cords inclined with respect to the tire circumferential direction. In the manufacturing method, the rubber chafer is vulcanized at a temperature lower than the heating temperature when vulcanizing and molding the green tire to prepare a semi-vulcanized rubber chafer, and both sides of the semi-vulcanized rubber chafer are manufactured. Of the non-vulcanized rubber containing a tackifier so as to cover at least a part of the above.

In the present invention, the rubber chafer can be arranged around the bead core of the vulcanized pneumatic bias tire.

1 is a half sectional view of a pneumatic bias tire according to a first embodiment of the present invention. The schematic sectional drawing which shows the pneumatic bias tire manufacturing method of 1st Embodiment of this invention. The schematic sectional drawing which shows the pneumatic bias tire manufacturing method of 1st Embodiment of this invention. The half cross-sectional view of the pneumatic bias tire of 2nd Embodiment of this invention.

The present embodiment will be described with reference to the drawings. It should be noted that the present embodiment is merely an example, and modifications appropriately made without departing from the spirit of the present invention are included in the scope of the present invention. For convenience of description, the drawings may be exaggerated in length or shape, or may be drawn schematically. However, such drawings are merely examples, and do not limit the interpretation of the present invention.

First, the structure of the pneumatic bias tire manufactured according to this embodiment will be described with reference to FIG. Since this pneumatic bias tire is a bilaterally symmetrical tire, the illustration of the left half is omitted.

As shown in FIG. 1, the pneumatic bias tire manufactured according to the present embodiment includes a pair of bead portions 1 provided on both sides in the tire width direction, and a carcass layer 2 bridged between the pair of bead portions 1. And a down ply layer 4 that is provided so as to overlap the outside of the carcass layer 2, and an inner liner 8 that is disposed inside the carcass layer 2 and that retains air pressure and that has an excellent function of blocking gas permeation. ing. The pneumatic bias tire of this embodiment may be configured as a tubeless tire in which no tube is arranged. Further, the pneumatic bias tire of the present embodiment may be a tubular tire in which a tube is arranged inside the carcass layer 2 and the tube is filled with air.

The bead portion 1 is composed of a bead core 10 in which a bundle of steel wires is covered with rubber, and a rubber bead filler 11 provided on the tire radial outside thereof.

Around the bead portion 1, the carcass layer 2 is folded back from the inner side in the tire width direction to the outer side and wound up to the outer side in the tire radial direction.

The carcass layer 2 is composed of two or more (three in the present embodiment) bias plies 2a, 2b, 2c. The bias plies 2a, 2b, 2c forming the carcass layer 2 are made of topping rubber with ply cords made of organic fibers arranged in a direction inclined at a predetermined angle with respect to a direction orthogonal to the tire circumferential direction (that is, a radial direction). A plurality of bias plies are provided so that the ply cords intersect each other between adjacent plies.

The down ply layer 4 is composed of one or more down plies 4a and 4b (two in this embodiment). The down plies 4a and 4b forming the down ply layer 4 are made of the same bias plies as the bias plies 2a, 2b and 2c, and the ply cords are provided so that the ply cords cross each other between the adjacent plies.

A belt 12 and a tread rubber 13 are provided outside the down plies 4a and 4b in the tire radial direction. A sidewall rubber 14 is provided outside the down plies 4a and 4b in the tire width direction.

A rubber chafer 3 is provided outside the folded-back portion of the bias plies 2a, 2b, 2c in the bead portion 1 so as to wind the bead portion 1.

More specifically, the rubber chafer 3 is provided on the tire width direction inner side of the bead portion 1 and on the tire width direction inner side of the bias plies 2a, 2b, and, like the bias ply 2a, 2b, around the bead core 10 in the tire width direction. It is folded back to the outside and wound up to the outside in the tire radial direction outside the winding portion of the bias plies 2a and 2b in the tire width direction. In the rubber chafer 3, a portion located inside the bead portion 1 in the tire width direction is an inner winding portion 31, and a portion located outside the bead portion 1 in the tire width direction is an outer winding portion 32.

Adhesive rubber portions 6 formed by vulcanizing an unvulcanized rubber composition containing a tackifier are provided on both surfaces of the rubber chafer 3. The adhesive rubber portion 6 of the present embodiment includes an outer adhesive rubber portion 6a that covers an outer surface (a surface facing the outer surface) of the rubber chafer 3 and an inner surface of the rubber chafer 3 (a surface facing the bead portion 1). And an inner adhesive rubber portion 6b for covering the entire surface of the rubber chafer 3 with the outer adhesive rubber portion 6a and the inner adhesive rubber portion 6b.

The inner winding portion 31 of the rubber chain 3 is in contact with the tire radial inner end of the inner liner 8 via the adhesive rubber portion 6. The outer winding portion 32 of the rubber chain 3 is in contact with the tire radial inner end of the sidewall rubber 14 via the adhesive rubber portion 6.

The tackifier contained in the adhesive rubber portion 6 is an additive that imparts tack to the unvulcanized rubber composition, and is also called a tackifier. As the resin used as such a tackifier, for example, a phenol resin, a coumarone resin, a terpene resin, a rosin resin, an aromatic vinyl polymer (α-methylstyrene and/or obtained by polymerizing styrene) Resins) and the like, and these may be used alone or in combination of two or more kinds.

Examples of the phenol resin include phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, and oil-modified phenol formaldehyde resin. Examples of the coumarone-based resin include coumarone resin and coumarone-indene resin. Examples of the terpene-based resin include polyterpene and terpene-phenol resin. Examples of the rosin-based resin include natural resin rosin and rosin-modified resin obtained by modifying it by hydrogenation, disproportionation, dimerization, esterification, or the like. Examples of the aromatic vinyl polymer include a homopolymer of α-methylstyrene, a homopolymer of styrene, and a copolymer of α-methylstyrene and styrene.

Among these, it is preferable to use synthetic resin tackifiers such as phenol resins and alkylphenol resins, natural resin tackifiers such as coumarone-indene resins, and rosin derivatives.

Moreover, the compounding quantity of a tackifier is not specifically limited if the desired peeling force is obtained. With respect to the desired peeling force, the peeling force of the adhesive rubber portion 6 with respect to the unvulcanized inner liner 8 and the sidewall rubber 14 is preferably 3.43 N or more. Here, the peeling force refers to a peeling sample attached to the unvulcanized inner liner 8 or the sidewall rubber 14 and a pulling speed of 50 mm/min at room temperature using a tensile tester according to JIS K 6854-3:1999. Is the average peeling force measured by performing a peeling test by the T-shaped method.

Next, a method for manufacturing the pneumatic bias tire shown in FIG. 1 will be described. The pneumatic bias tire manufacturing process is roughly divided into primary molding, secondary molding, and vulcanization molding.

As shown in FIG. 2A, the inner liner 8 and the three bias plies 2a, 2b, 2c are attached to the center of the molding drum D in the axial direction (drum axial direction), and the bias plies 2a, 2b, 2c are attached. The two bead portions 1 are arranged on the outer side of the so as to be spaced apart in the axial direction of the molding drum D.

Next, as shown in FIG. 2B, the two widthwise outer portions of the bead portions 1 are turned up so as to wrap the bead portions 1, respectively.

Next, as shown in FIG. 2C, the down plies 4a and 4b are attached to the outside of the carcass layer 2 including the three bias plies 2a, 2b and 2c.

Next, as shown in FIG. 3A, the rubber chafer 3 provided with the adhesive rubber portions 6a and 6b is attached around the bead portion 1 so as to wind the bead portion 1.

Here, the rubber chainer 3 wound around the bead portion 1 is a semi-vulcanized rubber chainer obtained by pre-vulcanizing an unvulcanized rubber member molded into a predetermined shape by an extruder (not shown). Pre-vulcanization refers to partial vulcanization in a rubber member state by heating to a semi-vulcanized state before a green tire molding step, and is also called pre-vulcanization. The pre-vulcanization condition is set to a vulcanization temperature lower than the vulcanization conditions for vulcanizing and molding a green tire described later. As an example, the rubber member is placed in a vulcanization chamber (not shown), and the rubber member is heated at 80 to 120° C. for 40 to 50 minutes for prevulcanization.

Then, the adhesive rubber portions 6 are provided on both surfaces of the semi-vulcanized rubber chafer 3 obtained by pre-vulcanization, and the green case 15 is molded. Here, the adhesive rubber portion 6 is a sheet-like rubber member obtained by molding an unvulcanized rubber composition containing a tackifier according to the shape of the semi-vulcanized rubber chafer 3. It is provided by sticking it on both sides. The thickness of the sheet-shaped rubber member attached to both surfaces of the semi-vulcanized rubber chafer 3 is not particularly limited, but may be 0.4 mm, for example.

Next, as shown in FIG. 3B, secondary molding is performed in which the sidewall rubber 14, the belt 12 and the tread rubber 13 are attached to the outside of the green case 15. The sidewall rubber 14, the belt 12, and the tread rubber 13 are laminated in advance to complete the tread body 16. In the secondary molding, as shown in FIG. 3B, the tread body 16 is attached to the outer diameter portion of the green case 15. A green tire 18 is formed by integrating the green case 15 and the tread body 16. The green tire 18 is stitched to remove air between the tire constituent members, and the secondary molding is completed.

After the secondary molding is completed, vulcanization molding is performed. In vulcanization molding, the green tire 18 is put into a mold and vulcanization molded under predetermined vulcanization conditions. As an example of the vulcanization conditions here, the green tire 18 is heated and held at 140 to 180° C. for 10 to 100 minutes to vulcanize the green tire 18. When the vulcanization molding is completed, the pneumatic bias tire is completed.

In the pneumatic bias tire of the present embodiment as described above, since the rubber chafer 3 is provided with the adhesive rubber portion 6 obtained by vulcanizing the unvulcanized rubber containing the tackifier, the rubber chafer 3 is not vulcanized. When the green tire 18 is manufactured using the semi-vulcanized rubber chainer 3 in which the rubber member is pre-vulcanized, the semi-vulcanized rubber chainer 3 does not peel off or shift in position, and the desired position can be obtained. A semi-vulcanized rubber chafer 3 can be arranged.

Moreover, in the case of a green tire manufactured by using the semi-vulcanized rubber chafer 3, the rubber fluidity is reduced around the bead portion 1 during vulcanization molding, so that a rubber chain having a desired thickness around the bead portion 1 is obtained. Har 3 can be arranged.

Further, in the present embodiment, since the adhesive rubber portion 6 is provided on the semi-vulcanized rubber chainer 3 by sticking the sheet-shaped rubber member to the semi-vulcanized rubber chainer 3, the workability of manufacturing the green tire is improved. You can

(Second embodiment)
FIG. 4 is a cross-sectional view showing a part of the pneumatic bias tire according to the second embodiment. In the second embodiment, adhesive rubber portions 6 are provided on both sides of the end portions of the inner winding portion 31 and the outer winding portion 32 of the rubber chainer 3 over the entire tire circumferential direction, and the central portion of the rubber chainer 3, that is, the rubber chainer. This is different from the first embodiment in that the adhesive rubber portion 6 is not provided in the portion of the heart 3 located radially inside the bead core 10.

Even in such a case, similarly to the first embodiment, when the green tire 18 is manufactured, the semi-vulcanized rubber chafer 3 is not peeled off or misaligned, and the semi-vulcanized rubber chafer 3 is semi-vulcanized at a desired position. It is possible to arrange the vulcanized rubber chainer 3 or to reduce the fluidity of the rubber around the bead portion 1 during vulcanization molding so as to arrange the rubber chainer 3 having a desired thickness around the bead portion 1. You can

In addition, in FIG. 4, the case where the adhesive rubber portions 6 are provided on both surfaces of the rubber chain 3 by sticking sheet-shaped rubber members to the inner surface and the outer surface of the rubber chain 3 is shown. The sheet-shaped rubber member may be folded back around the end portion of the rubber chafer 3 so that the end portion of the rubber chamfer 3 is rolled up, and the adhesive rubber portions 6 are provided on both surfaces of the rubber chafer 3.

(Example of change)
The above embodiments are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention.

In the above-described first and second embodiments, the case where the sheet rubber member is attached to the semi-vulcanized rubber chafer 3 to form the adhesive rubber portion 6 has been described, but instead of this, application of rubber glue Thus, the adhesive rubber portions 6 may be provided on both sides of the semi-vulcanized rubber chafer 3.

The rubber paste is obtained by dissolving a kneaded product of a rubber composition in an organic solvent, and examples of the organic solvent include volatile oils for rubber and various volatile organic solvents that dissolve rubber such as toluene and xylene. .. Preferably, butyl rubber dissolved in an organic solvent such as toluene can be used as the rubber paste.

Further, in the above-described first and second embodiments, the adhesive rubber portions 6 are provided on both surfaces of the semi-vulcanized rubber chafer, but the whole or a part of one surface of the semi-vulcanized rubber chafer is provided. The adhesive rubber portion 6 may be provided on the.

Further, in the above-described first and second embodiments, the case where the downply layer 4 is provided on the outside of the carcass layer 2 is described, but the present invention is also applicable to a pneumatic bias tire that does not include the downply layer 4. The invention can be applied.

1...Bead part, 2...Carcass layer, 2a...Bias ply, 2b...Bias ply, 2c...Bias ply, 3...Rubber chafer, 4...Down ply layer, 4a...Down ply, 4b...Down ply, 6...Adhesion Rubber part, 6a... Outer adhesive rubber part, 6b... Inner adhesive rubber part, 8... Inner liner, 10... Bead core, 11... Bead filler, 12... Belt, 13... Tread rubber, 14... Sidewall rubber, 15... Green case , 16... Tread body, 18... Green tire

Claims (10)

A bead portion, a carcass layer folded back around the bead portion so as to wrap around the bead portion, and a rubber chafer folded back around the bead portion so as to wrap around the bead portion from the outside of the carcass layer. In the pneumatic bias tire, wherein the carcass layer has a plurality of bias plies having carcass cords inclined with respect to the tire circumferential direction,
A pneumatic bias tire in which an adhesive rubber portion obtained by vulcanizing unvulcanized rubber containing a tackifier is provided so as to cover at least a part of both surfaces of the rubber chafer. The pneumatic bias tire according to claim 1, wherein the adhesive rubber portion covers the entire rubber chafer. The pneumatic bias tire according to claim 1, wherein the adhesive rubber portion covers only an end portion of the rubber chafer. The pneumatic bias tire according to claim 1, wherein the adhesive rubber portion is folded back around the end portion of the rubber chafer so as to wrap around the end portion. A bead portion, a carcass layer folded back around the bead portion so as to wrap around the bead portion, and a rubber chafer folded back around the bead portion so as to wrap around the bead portion from the outside of the carcass layer. In the method for manufacturing a pneumatic bias tire, wherein the carcass layer is vulcanized and molded into a green tire having a plurality of bias plies having carcass cords inclined with respect to the tire circumferential direction,
Pre-vulcanizing the rubber chainer to produce a semi-vulcanized rubber chainer,
A method for manufacturing a pneumatic bias tire, comprising a step of providing an adhesive rubber portion made of unvulcanized rubber containing a tackifier so as to cover at least a part of both surfaces of the semi-vulcanized rubber chafer. The method for manufacturing a pneumatic bias tire according to claim 5, wherein in the step, the adhesive rubber portion is provided so as to cover the entire rubber chafer. The method for manufacturing a pneumatic bias tire according to claim 5, wherein in the step, the adhesive rubber portion is provided so as to cover only an end portion of the rubber chafer. The method for producing a pneumatic bias tire according to claim 5, wherein, in the step, the adhesive rubber portion is provided by folding back around the end portion of the rubber chafer so as to wind the end portion. The method for manufacturing a pneumatic bias tire according to claim 5, wherein the adhesive rubber portion is provided by applying a rubber paste in the step. The method for manufacturing a pneumatic bias tire according to claim 5, wherein in the step, the adhesive rubber portion is provided by adhering a sheet-shaped rubber member.

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