JP2001269945A - Tire and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire and the manufacturing method therefor capable of displaying original excellent bead part durability without damaging a bead part during rim assembling and without rim sliding or rim friction during practical use in the tire of bladderless vulcanization. SOLUTION: Molding has (1) a process for molding a composite body of inner liner rubber covering a cylindrical thin film sheet and the whole face of the outside, (2) a process for cutting the composite body by being matched to the mutual circumferential length of bead core inside neighborhood along the toroidal carcass of a tire cross section, (3) a process for molding an unvulcanized tire by inserting the composite body into a molding drum after cutting and sticking a carcass ply and a residual tire constitution member on the inserted inner rubber. A pressurizing and heating medium is directly introduced in the inside of the unvulcanized tire of the inside of a metal mold loaded in the metal mold of a vulcanizing machine to be vulcanized on the unvulcanized tire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tire and a tire, and more particularly, to a vulcanized tire without using a bladder when vulcanizing an unvulcanized tire having a shape close to a product tire. A method for manufacturing a tire for vulcanizing a pneumatic radial tire with high thermal efficiency by directly introducing a pressurizing / heating medium into the inside and a tire manufactured using this method. The present invention relates to a tire manufacturing method and a tire capable of avoiding and maintaining superior bead portion durability.

[0002]

2. Description of the Related Art A radial ply tire is formed by laminating various members on a molding drum to complete an unvulcanized tire having a shape close to a product tire, and the unvulcanized tire is placed in a mold of a vulcanizer. And vulcanized. At this time, the pressurizing / heating medium (generally, saturated steam or gas) introduced into the unvulcanized tire is generally pressed by a bladder into a mold and heated. .

[0003] The use of a bladder during vulcanization is such that when a pressurizing / heating medium is applied directly to the inside of an unvulcanized tire, the pressing / heating medium damages the thin gauge inner liner rubber or carcass ply cord. This is to avoid inconvenience of causing or deteriorating.

[0004] On the other hand, vulcanization using a bladder, however, is disadvantageous in terms of thermal efficiency, bladder production and bladder replacement in terms of productivity and production cost in the vulcanization process. Therefore, in recent years, bladderless vulcanization without using a bladder has attracted attention.

[0005] With respect to this bladderless vulcanization, for example, Japanese Patent Application Laid-Open No. 10-29248 discloses that in a molding step of an unvulcanized tire, a cylindrical thin film body in which a rubber layer is coated on an outer surface of a resin film is used as another cylindrical tire. It is arranged on the inner peripheral side of the constituent member to form a united member, and a pressurized fluid is introduced into the inside of the thin film body, whereby the cylindrical united member is swelled and deformed, and the remaining tire members are stuck to the uncompressed member. In the vulcanization process,
A tire bladderless vulcanization method has been proposed in which a hot-pressing medium is directly supplied into an unvulcanized tire housed in a mold to perform vulcanization of the tire.

[0006]

However, it has been found that the bladderless vulcanization method proposed in the above publication has the following disadvantages. In other words, the tire after vulcanization has a resin film such as polyethylene around the bead portion, so that the periphery of the bead portion is easily damaged when assembling the tire, or the rim assembly tire is actually mounted on the vehicle. It has been found that a slip phenomenon (referred to as rim slip) occurs between the bead portion and the rim during use, and as a result, there is an inconvenience that the rim is rubbed and the durability of the bead portion is reduced.

[0007] Accordingly, the invention described in claims 1 to 6 of the present invention is to eliminate the above-mentioned inconvenience, that is, in a product tire that has undergone bladderless vulcanization, damage around the bead portion when assembling the rim, etc. Without the inconvenience of
It is an object of the present invention to provide a tire manufacturing method and a tire that can exhibit originally excellent bead portion durability without causing rim slippage or rim rubbing during actual use.

[0008]

According to a first aspect of the present invention, there is provided a tread portion having a pair of sidewall portions and a pair of bead portions connected to both sides of the tread portion. A radially-ply carcass extending in a toroidal manner between bead cores embedded in each bead portion, and a belt positioned on the outer periphery of the carcass, wherein the uncured Tire molding includes: (1) a step of molding a composite of a predetermined length of a cylindrical thin film sheet and an inner liner rubber covering the entire outer surface thereof; and (2) a pair of bead cores along a toroidal carcass in a tire cross section. Cutting the composite having the predetermined length in accordance with the peripheral length between adjacent parts; and (3) inserting the composite after cutting into a molding drum, and inserting the composite. Laminating the carcass ply and the remaining tire components on the inner liner rubber to form an unvulcanized tire, and placing the molded unvulcanized tire in a mold mounted on a vulcanizer. A method for producing a tire, characterized in that a vulcanized tire is vulcanized by loading and directly introducing a pressurizing / heating medium into an unvulcanized tire in a mold.

According to the invention described in claim 1, claim 2 is provided.
When the composite is inserted into a molding drum, the axial ends of the composite are positioned at one of a pair of bead core inside corresponding positions and a pair of bead core inner radial outside positions. Let it.

According to the first and second aspects of the present invention, as in the third aspect, the tire has a bead chafer covering a carcass ply around each bead core. Is attached to the inside of the carcass ply, and both ends of the inner liner rubber of the composite are overlapped with the bead chafer.

According to the first to third aspects of the present invention, as in the fourth aspect of the invention, when cutting the composite having the predetermined length, the inner liner rubber is provided in the thickness direction and at both ends. The cutting is performed in such a manner that the inner liner is inclined in the same direction and at the same angle, and in relation to the invention described in claim 4, as in the invention described in claim 5, the cutting angle of the inner liner is 30 degrees with respect to the direction orthogonal to the axial direction. ６０60 °.

According to another aspect of the present invention, there is provided a bead core having a tread portion, a pair of sidewall portions and a pair of bead portions connected to both sides thereof, and embedded in each bead portion. A tire having a carcass of a radial ply extending in a toroidal shape over each other and a belt located on the outer periphery of the carcass, wherein the tire has an inner liner rubber on an inner surface of the carcass, and is manufactured according to any one of claims 1 to 5. A tire manufactured by a method.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a cross-sectional view of the tire of the present invention, FIG. 2 is a cross-sectional view of an unvulcanized tire before vulcanization of the tire shown in FIG. 1, and FIG. 3 is applied to the unvulcanized tire shown in FIG. FIG. 4 is a perspective view of a composite of the cylindrical thin film sheet and the inner liner rubber after cutting, and FIG. 4 is a one-side sectional view of the composite, the carcass ply, and the bead chafer shown in FIG. It is.

In FIG. 1, a tire (pneumatic radial tire) 1 has a tread portion 2 and a pair of sidewall portions 3 and a pair of bead portions 4 connected to both sides thereof.
A radially-ply carcass 6 extending in a toroidal shape between bead cores 5 embedded in each bead portion 4, and a belt 7 located on the outer periphery of the carcass 6, an inner liner rubber 8 on the inner surface of the carcass 6, And a bead chafer 9 which is in contact with and covers the carcass 6. The bead chafer 9 allows both the case of a rubber-coated organic fiber cord layer and the case of a rubber chafer.

In FIG. 2, the unvulcanized tire 11 has a shape close to the product tire 1 after vulcanization. Unvulcanized tire 1
Reference numeral 1 denotes a tread portion 12 serving as a tread portion 2 in the product tire 1, a sidewall portion 13 serving as a pair of sidewall portions 3, and a bead portion 14 serving as a pair of bead portions 4.
And

The unvulcanized tire 11 has a carcass ply 16 as a reinforcing member extending between unvulcanized bead cores (hereinafter, unvulcanized) 15 embedded in each bead portion 14 and an outer periphery thereof. Belt 1 attached to
7, an inner liner rubber 18 in contact with the inner surface of the carcass ply 16 extending in a toroidal shape and extending between the pair of bead portions 14, and a bead chafer 19. The inner liner rubber 18 has a thin film sheet 20 on its inner surface. Hereinafter, molding of the unvulcanized tire 11 mainly including the inner liner rubber 18 and the thin film sheet 20 will be described. In addition, for convenience of explanation, the thin film sheet 20 is illustrated by a thick gauge which is much larger than an actual gauge throughout the drawings.

As shown in FIG. 2, a cylindrical thin film sheet 20 and an inner liner rubber 18 covering the entire outer surface thereof are previously formed.
Is molded in advance. The length of the composite 21 in the axis X direction is a predetermined length that exceeds at least the required length. The predetermined length is described below.

Thereafter, referring to FIG. 1, the composite 2 is formed along the toroidal carcass 6 in the cross section of the tire 1 in accordance with the peripheral length between the vicinity of the inside of the tire of the pair of bead cores 5.
Cut 1 The above-mentioned predetermined length refers to this peripheral length.

Thereafter, as shown in FIG. 4, the composite 21 cut into a predetermined length is inserted into the molding drum 22 with the inner liner rubber 18 as the surface side. The carcass ply 16 and the remaining tire components are stuck on the inner liner rubber 18 of the inserted composite 21 to form a united member. In addition,
As shown, when the bead chafer 19 is required,
The bead chafer 19 is pasted to the carcass ply 16 in advance, and the bead chafer 19 is set inside the carcass ply 16 in the forming drum 22. Although each member is shown in FIG. 4 as being separated from each other, it is actually in a bonded state.

The remaining components are a pair of bead cores 1
5, belt 17, bead filler rubber 23, sidewall rubber 24 and tread rubber 25. For molding these members, a pair of bead cores 15 with bead filler rubber 23 attached to the carcass ply 16 in the state shown in FIG. 4 are set, and after the sidewall rubber 24 is attached, the pair of bead cores 15 are attached to the carcass ply 16. Locked and filled with pressurized gas inside the united members 16, 18, 19, 20 while narrowing the interval between the pair of bead cores 15,
The united member is expanded and deformed into a toroidal shape. Thereafter, the belt 17 and the tread rubber 25 are applied to the swelled and deformed united member.
And glue. Thus, the molding of the unvulcanized tire 1 is completed.

The unvulcanized tire 11 which has been molded in this way is loaded into a mold (not shown) mounted on a vulcanizer (not shown) and vulcanized inside the unvulcanized tire in the mold. The tire shown in FIG. 1 is obtained by directly vulcanizing the unvulcanized tire 11 by directly introducing a pressure / heating medium. In addition, the straight line Y shown in FIG. 2 is a bisection line of the unvulcanized tire 11, and the bisection line Y exists on the tire equatorial plane E shown in FIG.

Now, the tire 1 thus completed
However, as shown in FIG. 1, the thin film sheet 20 does not exist around the bead core 5 of the bead portion 4, so that the bead portion 4 is not damaged when the rim is assembled. Also, since the thin film sheet 20 does not exist in the bead portion 4 that contacts the rim,
Neither rim sliding nor rim rubbing occurs, and the original durability of the bead portion 4 is completely maintained.

Hereinafter, the composite 21 will be described in more detail. First, when the composite 21 is inserted into the molding drum 22, both ends in the axis X direction of the composite 21 are positioned at one of the corresponding position inside the pair of bead cores 15 or the radially outer position inside the pair of bead cores 15. Fits. FIG. 2 shows a case where both ends are located radially outward by a height h (mm) from the outer peripheral surface of the bead core 15. Thereby, the above effects can be guaranteed.

Next, as shown in FIGS. 2 and 4, both ends of the inner liner rubber 18 of the composite 21 are overlapped with the bead chafer 19. Accordingly, even if the pressurizing / heating medium directly hits the bead portion 14 where the thin film sheet 20 does not exist, since the rubber layer has a sufficient thickness, the cord of the carcass 16 is adversely affected. There is no.

Finally, as shown in FIG. 4, when cutting the composite 21 having a predetermined length, the inner liner rubber 18 is cut while being inclined in the thickness direction and in the same direction at both ends and at the same angle α. . By doing so, it is possible to prevent the pressurized / heated medium from entering the inside from the cut end of the composite 21. The cutting angle α of the inner liner 18 is
It is preferable that the angle is in the range of 30 to 60 degrees with respect to the direction perpendicular to the direction.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A radial ply tire for a passenger car having a size of 185 / 70R14, and an unvulcanized tire 11 is shown in FIG. 2, and a composite 21 of an inner liner rubber 18 and a thin film sheet 20 is shown in FIG. As indicated,
Carcass ply 16, inner liner rubber 18, bead chafer 19 and thin film sheet 20 on forming drum 22
Is as shown in FIG.

This time, as the thin film sheet 11, a polyethylene sheet having a gauge of 0.015 mm and a thickness of 1.0 m
m of inner liner rubber 18 was used. The cutting length of the composite 21 is set so that the height h from the outer peripheral surface of the bead core 15 at both ends of the composite 21 is 5 mm, and the cutting angle α of the inner liner 18 is set to 50 ° to mold the unvulcanized tire 11. And vulcanized with bladderless.

In order to confirm the performance of the example tires, comparative tires were manufactured according to the disclosure of the above-mentioned publication. The performance of both tires, partly including the appearance inspection, is mounted on the actual vehicle. (1) Damage check such as chipping of the bead when assembling the rim: (2) Rim slip amount during sudden braking by the actual vehicle ( mm): (3) Rim rubbing degree: (4) Bead part appearance inspection: Table 1 shows the results.

[0029]

[Table 1]

From the results shown in Table 1, there is no problem in appearance of the tire of the present invention at all, there is no problem in assembling the rim at all, and there is almost no problem in rim slipping and rubbing as compared with the comparative tire. I understand that there is no.

[0031]

According to the invention described in claims 1 to 6 of the present invention, in a product tire finished by bladder-less vulcanization, damage such as chipping around a bead portion does not occur at the time of rim assembly, and It is possible to provide a tire manufacturing method and a tire that can exhibit originally excellent bead portion durability without causing rim slippage or rim rubbing during use.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tire according to the present invention.

FIG. 2 is a sectional view of an unvulcanized tire before vulcanization of the tire shown in FIG.

FIG. 3 is a perspective view of a composite of a cut cylindrical thin film sheet and inner liner rubber applied to the unvulcanized tire shown in FIG. 2;

4 is a one-side cross-sectional view of the composite shown in FIG. 3 and a carcass ply and a bead chafer on a forming drum.

[Explanation of symbols]

 Reference Signs List 1 tire 2 tread portion 3 sidewall portion 4 bead portion 5 bead core 6 carcass 7 belt 8 inner liner rubber 9 bead chafer 11 unvulcanized tire 12 tread portion 13 sidewall portion 14 bead portion 15 bead core 16 carcass ply 17 belt 18 inner Liner rubber 19 Bead chafer 20 Thin film sheet 21 Composite 22 Molding drum 23 Bead filler rubber 24 Sidewall rubber 25 Tread rubber E Tire equatorial plane X Composite axis α Inner liner rubber cutting angle

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29K 105: 24 B29K 105: 24 B29L 30:00 B29L 30:00

Claims (6)

[Claims] 1. A carcass of a radial ply having a tread portion, a pair of side wall portions and a pair of bead portions connected to both sides thereof, and extending in a toroidal shape between bead cores embedded in each bead portion; A tire having an inner liner rubber on the inner surface of the carcass, comprising: (1) forming a cylindrical thin film sheet and an inner liner rubber covering the entire outer surface thereof; Molding a composite of a predetermined length; (2) along a toroidal carcass in a tire cross section;
Cutting the composite having the predetermined length in accordance with the circumferential length between the pair of bead cores, and (3) inserting the composite after cutting into a molding drum and placing the carcass ply on the inserted inner liner rubber. And bonding the remaining tire components to form an unvulcanized tire. The unvulcanized tire having been molded is loaded into a mold mounted on a vulcanizer, and the unvulcanized tire is A method for producing a tire, comprising: introducing a pressurizing / heating medium directly into a vulcanized tire; and vulcanizing an unvulcanized tire. 2. When the composite is inserted into a molding drum, both ends in the axial direction of the composite are positioned at one of a pair of inside positions corresponding to the inside of the bead core and a pair of radial positions outside the inside of the bead core. 2. The production method according to 1. 3. The tire has a bead chafer that covers a carcass ply around each bead core. Upon molding, the bead chafer is attached to the inside of the carcass ply, and the both ends of the inner liner rubber of the composite are joined. 3. The method according to claim 1, wherein the method overlaps with a bead chafer. 4. The cutting method according to claim 1, wherein in cutting the composite having the predetermined length, the inner liner rubber is cut while being inclined in the thickness direction and at the same direction and the same angle at both ends. Production method described in 1. 5. The manufacturing method according to claim 4, wherein a cutting angle of the inner liner is in a range of 30 to 60 ° with respect to a direction orthogonal to the axial direction. 6. A carcass of a radial ply having a tread portion, a pair of sidewall portions and a pair of bead portions connected to both sides thereof, and extending in a toroidal shape between bead cores embedded in each bead portion, and the carcass. A tire having an inner liner rubber on the inner surface of a carcass, comprising: a belt positioned on an outer periphery of the tire; and a tire manufactured by using the manufacturing method according to any one of claims 1 to 5.