JP2023026214A - Vulcanization molding bladder and tire manufacturing method - Google Patents

Abstract

To improve an appearance quality of a tire.SOLUTION: A vulcanization molding bladder 22, which molds an inner surface of a low cover 50, includes: a pair of bead sections 52; a pair of sidewall sections 54 extending from the bead sections 52; and a tread section 56 connecting the pair of sidewall sections 54. The vulcanization molding bladder 22 includes: a cylindrical body 22a; and ring-shaped flanges 22b provided at each end of the body 22a. A fiber 22c is included in at least a portion of the body 22a that is in contact with the inner surface of the pair of sidewall sections 54.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to vulcanization molding bladders and methods of manufacturing tires.

Japanese Patent Application Laid-Open No. 2016-93953 discloses a tire vulcanizing bladder that is arranged inside a low cover (referred to as a “green tire” in the same publication) and capable of holding the low cover by being inflated. ing. In such a tire vulcanizing bladder, when the low cover is held, the portion corresponding to the region from the belt end of the low cover toward the side portion is formed of a deformation suppressing portion whose deformation amount is suppressed more than other portions. there is The deformation suppressing portion is configured by attaching a reinforcing member to the inner peripheral surface. The reinforcing body is made of rubber like the bladder body. When the tire vulcanizing bladder is inflated and the low cover is held, expansion of the bladder body is suppressed by the reinforcing member by the deformation suppressing portion, and the region of the low cover extending from the belt end toward the side portion is deformed more than necessary. There is no Therefore, part of the low cover is not caught in the mold. As a result, it is said that it is possible to reliably prevent the deterioration of the mold caused by biting and the adhesion of the fallen rubber to the surface of the raw cover to be vulcanized next, resulting in defective products. ing.

JP 2016-93953 A

By the way, in the sidewall portion, a step may occur in the portion where the sheet-like rubber material is superimposed. Also, a step may remain in the sidewall portion of the tire after vulcanization molding. Such an event was observed in the inventor's trial production. The sidewall portion is decorated with characters, for example, and has a great influence on the appearance quality.

In the present disclosure, the vulcanization molding bladder that forms the inner surface of the low cover includes a pair of bead portions, a pair of sidewall portions extending from the bead portions, and a tread portion connecting the pair of sidewall portions. It is a molding bladder. The vulcanization molding bladder has a cylindrical body and ring-shaped flanges provided at both ends of the body. Fibers are contained in at least a portion of the trunk portion that contacts the inner side surfaces of the pair of sidewall portions.
By using the vulcanization molding bladder having such a configuration, the appearance quality of the vulcanized tire can be improved.

FIG. 1 is a cross-sectional view schematically showing a part of a tire vulcanizing apparatus 10. As shown in FIG. FIG. 2 is a schematic diagram of the raw cover 50 and the vulcanizing bladder 22. As shown in FIG. FIG. 3 is a schematic diagram of the low cover 50. As shown in FIG. FIG. 4 is a sectional view showing the joint 54b of the sidewall portion 54. As shown in FIG. FIG. 5 is a schematic diagram showing the vulcanization molding bladder 22. As shown in FIG. FIG. 6 is a sectional view taken along line VI-VI in FIG.

An embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. Each drawing is schematically drawn and does not necessarily reflect the real thing. Each drawing only shows an example and does not limit the present disclosure unless otherwise specified. Further, members and portions that perform the same functions are given the same reference numerals as appropriate, and overlapping descriptions are omitted. In addition, the notation "A to B" indicating a numerical range means "A or more and B or less" unless otherwise specified.

FIG. 1 is a sectional view schematically showing a part of a vulcanizing device 10 for tires. A tire can be manufactured by vulcanizing the raw cover 50 in the vulcanizing apparatus 10 .

<Low cover 50>
The raw cover 50 is obtained by bonding together members constituting the tire and preliminarily molding them. FIG. 2 is a schematic diagram of the raw cover 50 and the vulcanizing bladder 22. As shown in FIG. FIG. 2 shows the raw cover 50 and the vulcanization molding bladder 22 that is in contact with the inner surface of the raw cover 50 during vulcanization. 2 shows a cross section along the axial direction of the central axis of the low cover 50. As shown in FIG. In addition, in FIG. 2, the hatching which shows a cross section is abbreviate|omitted. FIG. 3 is a schematic diagram of the low cover 50. As shown in FIG. FIG. 3 shows a view of the raw cover 50 viewed from the outside in the radial direction. FIG. 4 is a sectional view showing the joint 54b of the sidewall portion 54. As shown in FIG. FIG. 4 shows a cross section along the circumferential direction of the sidewall portion 54 including the joint 54b.

As shown in FIG. 2, in this embodiment, the low cover 50 includes a pair of bead portions 52, a pair of sidewall portions 54 extending from the bead portions 52, and a tread portion connecting the pair of sidewall portions 54. 56. The bead portion 52 is a portion forming a radially inner end portion of the vulcanized tire. The bead portion 52 internally includes a bead core 52a and an apex 52b. The bead portion 52 is annularly provided at the radially inner end portion of the raw cover 50 . The sidewall portion 54 is a portion that constitutes the side surface of the vulcanized tire. The sidewall portion 54 extends from the bead portion 52 toward the radially outer end portion of the raw cover 50 . The tread portion 56 is a portion that forms a portion of the tire that comes into contact with the road surface after vulcanization. The tread portion 56 extends axially inward from the radially outer end portions of the pair of sidewall portions 54 . The tread portion 56 is cylindrical.

The raw cover 50 has a carcass 50a forming the skeleton of the raw cover 50 therein. A belt 50c that reinforces the tread portion 56 is arranged on the outer surface of the carcass 50a. The carcass 50a has, in the bead portion 52, an annular bead core 52a and an apex 52b extending radially outward along the carcass 50a from the annular bead core 52a. In the bead portion 52, the bead core 52a and the apex 52b are wrapped around and covered with the carcass 50a at the radially inner end portion.

The low cover 50 includes an inner liner 50b covering the inner surface, and sidewall rubber 54a and tread rubber 56a covering the outer surface. The outside of the tread portion 56 is covered with a tread rubber 56a. The outer sides of the sidewall portion 54 and the bead portion 52 are covered with a sidewall rubber 54a.

A sidewall rubber 54a covering the sidewall portion 54 and the bead portion 52 is formed in a sheet shape. In this embodiment, the sidewall rubber 54a is a sheet of rubber. As shown in FIG. 3, the sidewall rubber 54a is formed by winding one round in the circumferential direction of the low cover 50. As shown in FIG. Therefore, the sidewall portion 54 is formed with a joint 54b in which the sidewall rubber 54a is slightly overlapped (see FIG. 4).

<Vulcanizing device 10>
As shown in FIG. 1, the vulcanization apparatus 10 includes a bladder center mechanism 20 and a mold 30. As shown in FIG. The vulcanizing device 10 is a device for vulcanizing and molding the raw cover 50 . The vulcanization apparatus 10 introduces a high-temperature fluid from the inside of the vulcanization molding bladder 22 provided in the bladder center mechanism 20 to expand it, and presses the raw cover 50 against the mold 30 . The raw cover 50 is thereby heated and pressurized.

<Mold 30>
The mold 30 includes a first side mold 32 , a second side mold 34 facing the first side mold 32 , and a tread mold 36 . The outer shape of the vulcanized tire is formed by pressing the raw cover 50 against the mold 30 . The bead portion 52 and the sidewall portion 54 are pressed against the first side mold 32 and the second side mold 34 . A tread portion 56 is pressed against the tread mold 36 .

During vulcanization, the raw cover 50 is set on the second side mold 34 . A cylinder (not shown) is attached to the first side mold 32 so that it can move up and down. The first side mold 32 is configured to rise when the raw cover 50 is set on the second side mold 34 and to descend during vulcanization. The tread mold 36 is composed of a plurality of molds. The tread mold 36 is configured to open and close according to the elevation of the first side mold 32 by means of guides or the like attached to the first side mold 32, for example. That is, the tread mold 36 is in an open state before vulcanization, but when the first side mold 32 descends during vulcanization, the tread mold 36 is in a closed state in conjunction with this.

<Bladder center mechanism 20>
The bladder center mechanism 20 includes a vulcanization molding bladder (hereinafter also simply referred to as “bladder”) 22 , a pair of clamp rings 27 a and 27 b and a center post 26 . The bladder 22 is formed in a cylindrical shape, and both end portions (flange portions 22b) are attached to disk-shaped clamp rings 27a and 27b, respectively. An upper clamp ring 27 a is attached to the upper portion of the center post 26 . The lower clamp ring 27b has a through hole 27b1 through which the center post 26 passes.

The center post 26 is configured to be movable up and down by a cylinder (not shown). Thereby, the spacing between the pair of clamp rings 27a, 27b can be changed. During vulcanization, the center post 26 is lowered and the gap between the clamp rings 27a and 27b is narrowed according to the width of the low cover 50. As shown in FIG. After vulcanization, the center post 26 rises and the distance between the clamp rings 27a, 27b widens. The center post 26 is configured to move up and down as the first side mold 32 moves up and down.

The space inside bladder 22 is independent of the space outside bladder 22 . Bladder center mechanism 20 is also configured to allow hot fluid to be introduced into the internal space of bladder 22 during vulcanization. This embodiment is configured such that high-temperature fluid can be introduced from the through hole 27b1 of the clamp ring 27b toward the internal space of the bladder 22. As shown in FIG.

<Vulcanization molding bladder 22>
The vulcanization molding bladder 22 molds the inner surface of the raw cover 50 . FIG. 5 is a schematic diagram showing the vulcanization molding bladder 22. As shown in FIG. FIG. 5 schematically shows the portion containing the fiber 22c, the direction of the first fiber 22c1, and the direction of the second fiber 22c2. The vulcanizing bladder 22 has a trunk portion 22a and ring-shaped flange portions 22b provided at both ends of the trunk portion 22a.

The flange portion 22b is a portion attached to each of the clamp rings 27a and 27b. The body portion 22a has a barrel shape whose circumference gradually increases inwardly from the flange portion 22b. The bladder 22 is an elastic body made of rubber. As the rubber-made elastic body used for the bladder 22, conventionally known ones can be adopted without particular limitation, and there is no particular limitation. When the bladder 22 is vulcanized and hot fluid is introduced therein by the bladder center mechanism 20, the body portion 22a expands. Thereby, the raw cover 50 is pressed against the mold 30 while being heated and vulcanized.

The bladder 22 includes fibers 22c in at least a portion of the body portion 22a that contacts the inner side surfaces of the pair of sidewall portions 54. As shown in FIG. In this embodiment, the fibers 22c are included continuously in the circumferential direction at portions of the trunk portion 22a that contact the inner side surfaces of the pair of sidewall portions 54 . The portion containing the fibers 22c has higher elastic strength than the portion not containing the fibers 22c.

In this embodiment, nylon fibers are used as the fibers 22c. The fibers 22c included in the trunk portion 22b are not particularly limited. Fibers such as polyester, aramid, and rayon can be used as the fibers 22c. A nylon fiber can be preferably used as the fiber 22c. Since the bladder 22 contains high-strength nylon fibers, the raw cover 50 can be pressed against the mold 30 more strongly. Although the thickness of the fiber is not particularly limited, for example, fibers with a diameter of about 0.4 to 1.0 mm can be used.

By the way, as described above, the sidewall portion 54 of the low cover 50 is composed of the sheet-like sidewall rubber 54a (see FIG. 3). The sidewall portion 54 is formed with a joint 54b in which edges of a sheet-like sidewall rubber 54a are slightly overlapped. The joint 54b is thicker than the rest of the sidewall portion 54. As shown in FIG. According to the findings of the present inventors, if the joint is not sufficiently crushed during vulcanization, there is a concern that the joint may remain in a raised state after vulcanization. In this way, it is easy for the joint to remain in a raised state in a large tire having a thick sidewall portion such as a tire for SUV (Sport Utility Vehicle), for example. Since the sidewall portion constitutes the side surface of the tire after vulcanization, the swelling of the joint has a greater influence on the appearance quality than other portions.

As shown in FIG. 5, the fibers 22c include a plurality of first fibers 22c1 extending parallel to the first direction D1 and a plurality of second fibers 22c2 extending parallel to a second direction D2 different from the first direction D1. It is formed in a mesh shape by The first fibers 22c1 and the second fibers 22c2 are inclined about 50 to 60 degrees with respect to the circumferential direction of the trunk portion 22a. The first fibers 22c1 and the second fibers 22c2 are inclined in opposite directions from the circumferential direction of the trunk portion 22a. The angle of the fibers 22c with respect to the circumferential direction of the trunk portion 22a is not particularly limited. The angle of the fiber 22c may be, for example, 40 degrees or more, preferably 50 degrees or more. Also, the angle of the fiber 22c may be 70 degrees or less, preferably 60 degrees or less. In this way, the fibers 22c are inclined with respect to the circumferential direction of the trunk portion 22a, so that the bladder 22 can be pressed more strongly.

Fibers 22c are contained within body 22a of bladder 22 . FIG. 6 is a sectional view taken along line VI-VI in FIG. FIG. 6 shows a portion of the bladder 22 containing the fibers 22c. In this embodiment, as shown in FIG. 6, the body 22a of the bladder 22 is composed of three layers of rubber sheets 23, 24, 25. As shown in FIG. The rubber sheet 23 of the outer layer and the rubber sheet 25 of the inner layer are composed of one rubber sheet. As the rubber sheet 24 of the intermediate layer, the rubber sheet 24a containing the fibers 22c described above is used at the portion that abuts on the inner surface of the sidewall portion 54. As shown in FIG. As the rubber sheet 24 of the intermediate layer, a rubber sheet 24b that does not contain the fibers 22c is used in a portion other than the portion that abuts on the inner surface of the sidewall portion 54. As shown in FIG.

As shown in FIG. 2, the fibers 22c are included in a portion of the trunk portion 22a that contacts the inner surface of the end portion 54c of the sidewall portion 54 on the bead portion 52 side. Here, the end portion 54c on the side of the bead portion 52 is near the tip of the apex 52b extending radially from the annular bead core 52a.

In the embodiment described above, the bladder 22 includes the fibers 22c in the portions of the trunk portion 22a that contact the inner side surfaces of the pair of sidewall portions 54. As shown in FIG. When the raw cover 50 is vulcanized using such a bladder 22, the raw cover 50 is strongly pressed against the mold 30 at the portion containing the fibers 22c because the elastic strength is high. Thereby, for example, the thick portion of the low cover 50, such as the joint 54b of the sidewall portion 54, can be strongly crushed. As a result, a step (joint 54b) generated in the portion where the sheet-like rubber material is superimposed on the side wall portion 54 of the low cover 50 can be eliminated more neatly. Therefore, the appearance quality of the sidewall of the tire can be improved.

Also, in the embodiment described above, the fibers 22c are contained inside the body portion 22a of the bladder 22 . As a result, the portion containing the fibers 22c has a high thermal conductivity. In other words, temperature unevenness is less likely to occur in the portion where the fibers 22c are included. As a result, the appearance quality of the tire can be improved in the portion of the bladder 22 pressed by the portion containing the fibers 22c.

In the embodiment described above, the fibers 22c are included continuously in the circumferential direction at the portions of the trunk portion 22a that contact the inner side surfaces of the pair of sidewall portions 54 . Therefore, the raw cover 50 can be pressed against the mold 30 more strongly on the entire circumference of the body portion 22 a that contacts the inner side surface of the sidewall portion 54 . That is, it is not necessary to align the joint 54b of the raw cover 50 with the portion of the bladder 22 containing the fibers 22c.

In the above-described embodiment, the fibers 22c are included in the portion of the trunk portion 22a that contacts the inner surface of the end portion 54c of the sidewall portion 54 on the bead portion 52 side. By the way, the rubber member forming the low cover 50 is rolled up with respect to the bead core 52a and the apex 52b. Therefore, the thickness of the sidewall portion 54 starts to increase from the end portion 54c on the bead portion 52 side. According to the findings of the present inventor, the end portion 54c is difficult to press against the mold 30, and air tends to accumulate during vulcanization. If air remains between the mold 30 and the raw cover 50 during vulcanization, there is a concern that bares may occur in the vulcanized tire. Since the portion of the bladder 22 that contacts the end portion 54c contains the fibers 22c, air is less likely to accumulate between the mold 30 and the vicinity of the end portion 54c. Thereby, occurrence of bares can be reduced. It is preferable that the fibers 22c have a width of, for example, about 100 mm to 150 mm.

In this embodiment, the fibers 22c are not included in the portion of the trunk portion 22a that contacts the inner surface of the tread portion 56. As shown in FIG. That is, the portion that is strongly pressed against the mold 30 is limited to the sidewall portion 54 . As a result, the tread portion 56 is easily pressurized uniformly.

As described above, in the trunk portion 22a, the fibers 22c are included in the portion that contacts the inner surface of the sidewall portion. However, the range in which the fibers 22c are included is not limited to such a form unless otherwise specified. The fibers 22c may be included intermittently or partially in the circumferential direction. For example, in the trunk portion 22a, the fibers 22c may be included only in the portion where the joint 54b of the sidewall portion 54 is formed.

Moreover, at least a portion of the body portion 22a that contacts the inner surface of the tread portion 56 may also contain the fibers 22c. Furthermore, the fibers 22c included in at least a portion of the portion contacting the inner surface of the tread portion 56 and the fibers 22c included in at least a portion of the portion contacting the inner surface of the pair of sidewall portions 54 are independent. may be By selectively providing a portion containing the fibers 22 c in this manner, a desired position of the raw cover 50 can be strongly pressed against the mold 30 . Thereby, the appearance quality of the tire can be further improved.

Various descriptions of the vulcanization molding bladder disclosed herein have been made above. However, the vulcanizable bladders disclosed herein are not limited to the above-described embodiments or variations, unless specifically noted. In addition, various configurations of the embodiments and modified examples can be appropriately combined as long as they do not hinder each other. This specification includes the following disclosure, which is not limited to the embodiments described above.

The present disclosure (1) is for vulcanization molding for molding the inner surface of a raw cover having a pair of bead portions, a pair of sidewall portions extending from the bead portions, and a tread portion connecting the pair of sidewall portions. The bladder has a cylindrical body and ring-shaped flanges provided at both ends of the body, and abuts against the inner side surfaces of the pair of sidewalls of the body. A vulcanizable bladder having fibers in at least a portion of the section.

The present disclosure (2) is the vulcanization molding bladder according to the present disclosure (1). In the present disclosure (2), the fibers are formed in a mesh shape by a plurality of first fibers extending parallel to a first direction and a plurality of second fibers extending parallel to a second direction different from the first direction. ing.

The present disclosure (3) is the vulcanization moldable bladder described in the present disclosure (1) or the present disclosure (2). In (3) of the present disclosure, the fibers are included continuously in the circumferential direction at a portion of the trunk portion that abuts on the inner side surfaces of the pair of sidewall portions.

Disclosure (4) is a vulcanizable bladder in any combination with any of Disclosures (1)-(3). In the present disclosure (4), the fiber is included in a portion of the trunk portion that abuts the inner surface of the end portion of the sidewall portion on the bead portion side.

Disclosure (5) is a vulcanizable bladder in any combination with any of Disclosures (1)-(4). In (5) of the present disclosure, the fibers are not included in a portion of the trunk portion that contacts the inner surface of the tread portion.

Disclosure (6) is a vulcanizable bladder in any combination with any of Disclosures (1)-(4). In the present disclosure (6), at least a portion of a portion of the trunk portion that contacts the inner surface of the tread portion contains fibers.

This disclosure (7) is the vulcanization molding bladder according to this disclosure (6). In the present disclosure (7), the fibers contained in at least a portion of the portion that contacts the inner surface of the tread portion and the fiber contained in at least a portion of the portion that contacts the inner surface of the pair of sidewall portions are ,be independent.

Disclosure (8) is a vulcanizable bladder in any combination with any of Disclosures (1)-(7). In the present disclosure (8), the fibers include nylon fibers.

The present disclosure (9) is a tire manufacturing method in which a raw cover is vulcanized using a vulcanization molding bladder of any combination with any one of the present disclosures (1) to (8).

10 vulcanization device 20 bladder center mechanism 22 vulcanization molding bladder 22a body portion 22b flange portions 23, 24, 24a, 24b, 25 rubber sheet 22c fiber 26 center post 27a, 27b clamp ring 27b1 through hole 30 mold 32 first side mold 34 second side mold 36 tread mold 50 low cover 50a carcass 50b inner liner 50c belt 52 bead portion 52a bead core 52b apex 54 sidewall portion 54a sidewall rubber 54b joint 54c end portion 56 tread portion 56a tread rubber

Claims (9)

A vulcanization molding bladder for molding an inner surface of a low cover having a pair of bead portions, a pair of sidewall portions extending from the bead portions, and a tread portion connecting the pair of sidewall portions,
a cylindrical torso;
and a ring-shaped flange provided at each end of the body,
A bladder for vulcanization molding, wherein fibers are contained in at least a portion of a portion of the body portion that abuts against the inner side surfaces of the pair of sidewall portions. 2. The method according to claim 1, wherein the fibers are formed in a mesh shape by a plurality of first fibers extending parallel to a first direction and a plurality of second fibers extending parallel to a second direction different from the first direction. A vulcanized molding bladder as described. 3. The bladder for vulcanization molding according to claim 1, wherein the fibers are continuously contained in the circumferential direction in a portion of the body portion that abuts against the inner side surfaces of the pair of sidewall portions. The vulcanization according to any one of claims 1 to 3, wherein the fiber is included in a portion of the body portion that contacts the inner surface of the end portion on the bead portion side of the sidewall portion. molded bladder. The vulcanization molding bladder according to any one of claims 1 to 4, wherein the fibers are not included in a portion of the body portion that contacts the inner surface of the tread portion. The vulcanization molding bladder according to any one of claims 1 to 4, wherein at least part of a portion of the body portion that contacts the inner surface of the tread portion contains fibers. The fiber contained in at least a part of the portion that abuts on the inner surface of the tread portion and the fiber contained in at least a portion of the portion that abuts on the inner surface of the pair of sidewall portions are independent of each other. Item 6. A vulcanization molding bladder according to item 6. The vulcanizable bladder according to any one of claims 1 to 7, wherein said fibers comprise nylon fibers. A method for manufacturing a tire, comprising vulcanizing a raw cover using the vulcanization molding bladder according to any one of claims 1 to 8.

Images