JP-2026076032-A - Bladder device and method for manufacturing a tire using the bladder device

Abstract

[Problem] To provide a bladder device that can improve bladder life while ensuring uniformity of tire vulcanization. [Solution] The bladder device 1 includes a support 30 equipped with a first clamp 31 and a second clamp 32, an inner bladder 21 held by the first clamp 31, and an outer bladder 22 held by the second clamp 32. The outer bladder 22 is deformable in conjunction with the expansion of the inner bladder 21 to press against the inner lumen T1 of the unvulcanized tire T, while being provided to be relatively movable at the contact portion with the inner bladder 21. The outer bladder 22 includes an inner lumen molding portion 23 facing the inner lumen T1. The inner lumen molding portion 23 includes at least a first portion 24 having a first thickness t1 and a second portion 25 having a second thickness t2 smaller than the first thickness t1. [Selection Diagram] Figure 3

Inventors

• 橋本 祐人
• 坂本 雅之
• 東浦 一樹
• 浅香 潤

Assignees

• 住友ゴム工業株式会社

Dates

Publication Date

20260511

Application Date

20241023

Claims (12)

1. A bladder device comprising a toroidal bladder that expands within the cavity of an unvulcanized tire set in a vulcanizing mold, thereby pressing the unvulcanized tire against the vulcanizing mold, A support equipped with a first clamp and a second clamp, An inner bladder, which is held by the first clamp and has a heating medium supplied inside, Includes an outer bladder, which is held by the second clamp and positioned outside the inner bladder, The outer bladder is deformed in accordance with the expansion of the inner bladder and can press against the inner cavity of the unvulcanized tire, while the contact portion with the inner bladder is provided to be movably relative to it. The outer bladder includes a cavity molding portion facing the cavity of the unvulcanized tire, The internal molded portion includes at least a first portion having a first thickness and a second portion having a second thickness smaller than the first thickness. Bladder device.
2. The bladder device according to claim 1, wherein the second portion and the first portion are adjacent in the radial direction of the unvulcanized tire.
3. The bladder device according to claim 1, wherein the second portion is provided at a position for pressing against the tread portion of the unvulcanized tire.
4. The bladder device according to claim 1, wherein the first portion is positioned to press against the sidewall portion of the unvulcanized tire.
5. The bladder device according to claim 1, wherein the difference between the first thickness and the second thickness is 1 to 8 mm.
6. The vulcanizing mold includes an upper mold and a lower mold. The first portion includes an upper first portion that presses against the sidewall portion on the upper mold side of the unvulcanized tire, and a lower first portion that presses against the sidewall portion on the lower mold side of the unvulcanized tire. The bladder device according to claim 1, wherein the lower first portion has a thickness smaller than the upper first portion.
7. The inner bladder includes a main body that presses against the inner lumen molding portion of the outer bladder. The bladder device according to any one of claims 1 to 6, wherein the main body portion has a third thickness that is substantially constant.
8. The bladder device according to claim 7, wherein the third thickness is 2 to 7 mm.
9. The inner bladder is made of butyl rubber, The bladder device according to any one of claims 1 to 6, wherein the outer bladder is formed of silicone rubber or fluororubber.
10. The bladder device according to any one of claims 1 to 6, wherein the lumen forming portion has at least one opening formed therein.
11. Multiple vent lines are provided on the outer circumferential surface of the inner bladder. The bladder device according to claim 10, wherein the vent line communicates with the opening.
12. A method for manufacturing a tire, comprising the step of vulcanizing the unvulcanized tire using a bladder apparatus described in any one of claims 1 to 6.

Description

This invention relates to a bladder device and a method for manufacturing a tire using the bladder device. Patent Document 1 below describes a tire vulcanization molding apparatus comprising a tire vulcanization mold and a bladder. The bladder is formed hollow from rubber and is positioned inside the tire vulcanization mold. Furthermore, the bladder gauges are such that Gs > Gc > Gt, where Gs corresponds to the tire sidewall, Gc corresponds to the axial X-center of the tire tread, and Gt corresponds to the axial X-end of the tire tread. Japanese Patent Publication No. 2005-238579 This is a cross-sectional view of a tire vulcanizing machine including a bladder device according to one embodiment of the present invention.This is an enlarged view of the left half of Figure 1.This is an enlarged view of the left half of Figure 1.This is an enlarged view of the left half of Figure 1.This is a cross-sectional perspective view of the outer bladder of this embodiment.This is a cross-sectional perspective view of the inner bladder of this embodiment.These are unfolded diagrams of the inner and outer bladder.(A) is an enlarged view of the first upper clamp and the second upper clamp shown in Figure 3, and (B) is an enlarged view of the first lower clamp and the second lower clamp shown in Figure 3.This is a cross-sectional perspective view of the outer bladder of another embodiment.This is a cross-sectional perspective view of the outer bladder of yet another embodiment. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings contain exaggerations and representations that differ from the actual structural dimensional ratios, in order to aid in understanding the present invention. Furthermore, where there are multiple embodiments, the same or common elements are denoted by the same reference numerals throughout the specification, and redundant descriptions are omitted. Figure 1 is a cross-sectional view of a tire vulcanizing machine 100 including a bladder device (hereinafter sometimes referred to as "device") 1, which illustrates one embodiment of the present invention. The tire vulcanizing machine 100 is used in the process of vulcanizing an unvulcanized tire T. An unvulcanized tire T is a cylindrical member in which unvulcanized sidewall rubber and tread rubber are bonded to a base material such as bead wire, carcass, or belt. The unvulcanized tire T, after being vulcanized in the vulcanization process, becomes a vulcanized tire (not shown). Thus, an unvulcanized tire T is a tire before vulcanization molding, and is also called a raw cover or green tire. Furthermore, the present invention can be applied to the vulcanization molding of various pneumatic tires, such as those for passenger cars and heavy loads. As shown in Figure 1, the unvulcanized tire T is set horizontally inside the tire vulcanizing machine 100 (vulcanizing mold 2). Therefore, the axial direction of the unvulcanized tire T is the same as the vertical (up and down) direction. This specification will be explained based on the horizontally positioned unvulcanized tire T. Figure 2 is an enlarged view of the left half of Figure 1. Figure 2 shows a meridian cross-section of an unvulcanized tire T. For convenience, a portion of the bladder 20 (shown in Figure 1), which will be described later, has been removed from Figure 2. As shown in Figure 2, the unvulcanized tire T includes a tread portion Ta, a pair of sidewall portions Tb located on both sides of the tread portion Ta, and bead portions Tc connected to each sidewall portion Tb. The tread portion Ta, sidewall portions Tb, and bead portions Tc of the unvulcanized tire T correspond to the tread portion, sidewall portion, and bead portion of a vulcanized tire, respectively. Furthermore, the unvulcanized tire T includes a cavity T1 containing the inner surface Td and an outer surface Te. The thickness ta of the tread portion Ta is formed to be greater than, for example, the thickness tb of each sidewall portion Tb and the thickness tc of each bead portion Tc. The thickness tb of the sidewall portion Tb is formed to be less than, for example, the thickness ta of the tread portion Ta and the thickness tc of the bead portion Tc. In an unvulcanized tire T set in a tire vulcanizing machine 100, the pair of sidewall portions Tb consist of an upper sidewall portion Tb1 and a lower sidewall portion Tb2 located below the upper sidewall portion Tb1. Similarly, the bead portion Tc consists of an upper bead portion Tc1 and a lower bead portion Tc2 located below the upper bead portion Tc1. As shown in Figure 1, the tire vulcanizing machine 100 of this embodiment includes a bladder device 1 and a vulcanizing mold 2. The tire vulcanizing machine 100 also includes, for example, a container 3 for opening and closing the vulcanizing mold 2, and a supply means 4 for supplying a heating medium G to the bladder device 1. The vulcanizing mold 2 includes, for example,