JP2010030067A - Vulcanization bladder and method for vulcanizing/molding tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vulcanization bladder which can improve the quality of a vulcanized/molded product tire and a method for vulcanizing/molding a green tire using the bladder. <P>SOLUTION: The vulcanization bladder 5 keeps a tire 2 clamped together with a mold 3 and presses the tire 2 to the mold 3 by expansion. The bladder 5 has a shape manipulation part made of a shape memory material which recovers in a vulcanization/molding temperature range. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vulcanizing bladder that sandwiches a tire with a mold and presses the tire against the mold, and a vulcanization molding method for a tire using the bladder.

In the tire vulcanization process, a raw tire is accommodated in a mold of a vulcanizer, a vulcanizing bladder made of an elastic hollow body that is inflatable is disposed inside the raw tire, and a high-temperature and high-pressure vulcanization is placed inside the bladder. A sulfur medium is supplied and the green tire is pressed from the inside toward the inner surface of the mold. At this time, the rubber and sulfur molecules of the raw tire are bonded by heat and pressure applied from the pradder, and elasticity and durability are imparted to the rubber. The final shape and tread pattern of the tire are formed by the mold at this time. After the vulcanization molding, the tire is taken out from the mold to obtain a product tire (see Patent Document 1). Thus, at the time of vulcanization molding, it is necessary to inflate the vulcanization bladder to press the raw tire from the inside, while when it is accommodated in the raw tire in the mold or when the product tire is taken out after vulcanization molding It is necessary that the shrinkage is smaller than the interval between the bead portions of the tire. For this reason, the vulcanizing bladder is generally composed of a highly flexible butyl rubber or the like.
JP 2004-9319 A

  FIGS. 1A to 1D are diagrams showing a vulcanization process of the green tire 2 using a general vulcanizer 1 described in Patent Document 1. FIG. In such a vulcanization process, first, the raw tire 2 is accommodated in the mold 3 (FIG. 1A), and then the vulcanizing bladder 5 fixed to the pradder ring 4 is disposed on the inner surface of the raw tire ( FIG. 1 (b)). Then, the vulcanization bladder 5 is expanded by supplying a vulcanization medium such as a mixed fluid of steam and nitrogen gas of about 180 to 200 ° C. into the vulcanization bladder 5 (FIG. 1C). . As a result, the raw tire 2 is pressed from the inside toward the inner surface of each mold, a tread pattern is formed on the outer surface of the raw tire 2, and the raw tire 2 is heated by the vulcanization medium and the mold 3. Vulcanized and molded. Then, the vulcanized tire 6 is extracted from the mold 3 to obtain a product tire 6 (FIG. 1 (d)). At this time, the vulcanizing bladder 5 is inflated into a predetermined shape along the inner surface of the tire by changing the gauge thickness of the rubber and controlling the expansion rate of each part.

  Although the vulcanization bladder is sufficiently adhered to the inner surface of the raw tire and the rubber is uniformly vulcanized to improve the quality of the product tire obtained, Therefore, there is a demand for more uniform vulcanization molding to further improve the quality of product tires.

  Accordingly, an object of the present invention is to provide a vulcanizing bladder that can improve the quality of product tires. Another object of the present invention is to provide a raw tire vulcanization molding method using such a vulcanization bladder.

  In order to achieve the above object, the first invention provides a vulcanizing bladder in which a tire is sandwiched between a mold and inflated to press the tire against the mold. The vulcanization bladder is characterized by having a shape correcting portion made of a shape memory material that recovers in the above temperature range.

  Furthermore, in the first invention, it is preferable that the shape memory compensation portion is disposed only in a region where the shape memory compensation portion contacts from the end portion (so-called hump portion) of the tire tread portion to the sidewall portion.

  Furthermore, in the first invention, the shape memory material is preferably recovered in the expansion direction of the vulcanization bladder.

  In addition, in the first invention, the shape memory material is preferably a shape memory alloy.

  The second invention includes a step of housing a tire in a mold, a step of disposing a vulcanizing bladder having the above-mentioned shape memory material on the inner surface side of the tire, and a vulcanizing product. And a step of vulcanizing and molding the tire by inflating the bladder and pressing the inner surface of the tire while performing shape correction with the shape memory material.

  According to the present invention, it is possible to provide a vulcanizing bladder that can improve the quality of a vulcanized product tire. It is also possible to provide a raw tire vulcanization molding method using such a vulcanization bladder.

  Next, embodiments of the present invention will be described with reference to the drawings. FIGS. 2A to 2D are views showing a vulcanization process using the vulcanization bladder according to the present invention. FIGS. 3A and 3B are views showing a vulcanization process of a raw tire using a vulcanizing bladder according to the present invention. FIG. 4 is a cross-sectional view of another vulcanizing bladder according to the present invention.

The vulcanization process of the green tire 2 using the vulcanizer 1 having the vulcanizing bladder 5 according to the present invention will be described below. First, as shown in FIG. 2A, the raw tire 2 is accommodated in the molds 3, 3, and 3 divided into three. Then, as shown in FIG. 2 (b), a vulcanizing bladder 5 fixed to the bladder ring 4 is disposed on the inner surface side of the raw tire 2. On the inner surface of the vulcanizing bladder 5, a shape memory alloy 10 is disposed as a shape memory material in a region that abuts from the end portion 8 of the tread portion 7 of the tire 6 to the sidewall portion 9. The shape memory alloy 10 has a property of being deformed and deformed in the expansion direction of the vulcanizing bladder 5 by heating during vulcanization molding. Next, as shown in FIG. 2C, a vulcanization medium of a mixed fluid of steam and nitrogen gas at about 180 to 200 ° C. is supplied to the inside of the vulcanization bladder 5, and the vulcanization bladder 5 is heated. Inflate. As a result, the vulcanizing bladder is appropriately inflated and deformed so as to press the raw tire 2 toward the inner surfaces of the molds 3, 3 and 3. At the same time, the shape memory alloy 10 is heated and deformed into a recovery shape set in the expansion direction of the vulcanizing bladder 5 and pressed from the end 8 of the tread portion 7 to the sidewall 9. Then, the vulcanized tire 6 is extracted from the mold 3 to obtain a product tire 6 (FIG. 2 (d)).
As described above, in the vulcanization process using the conventional vulcanization bladder 5 shown in FIG. 1, the gauge thickness of the rubber of the vulcanization bladder 5 varies depending on the part, and particularly from the end 8 of the tread portion 7 to the sidewall. Since the rubber in the region that is in contact with the portion 9 is thick, the vulcanizing bladder 5 is deformed into a shape that is in close contact with the inner surface of the raw tire 2 when the vulcanizing bladder 5 is expanded. Therefore, the pressure (arrow A) applied to the portion X from the end portion 8 of the tread portion 7 to the sidewall portion 9 of the tire 6 may be insufficient. As a result, the rubber of the portion X from the end portion 8 of the tread portion 7 of the tire 6 to the sidewall portion 9 flows, and there is a possibility that the rubber is not vulcanized into an appropriate shape.
On the other hand, when the vulcanizing bladder 5 according to the present invention is used, the shape memory alloy 10 disposed in the region that abuts from the end portion 8 of the tread portion 7 to the sidewall portion 9 during vulcanization molding is provided. Since the vulcanizing bladder 5 recovers in the expanding direction, the pressure applied to the portion X from the end portion 8 of the tread portion 7 to the sidewall portion 9 as compared with the case where the shape memory alloy 10 is not provided. Becomes larger. That is, the pressure (arrow A) applied to the inner surface of the raw tire 2 becomes uniform, and the tire 6 is uniformly vulcanized and molded as a whole, so that the quality of the obtained product tire 6 is improved. Further, the effect of disposing the shape memory alloy 10 on the vulcanizing bladder 5 as described above is that the curvature radius R is particularly small at the shoulder portion, and the sidewall portion from the end portion 8 of the tread portion 7 during vulcanization molding. This is conspicuous when manufacturing the tire 6 which is difficult to be pressed over the tire 9.
The shape memory alloy 10 can have any shape / configuration, for example, a plurality of cords extending in a direction inclined with respect to the circumferential direction of the vulcanizing bladder 5 as shown in FIG. The shape memory alloy 10 may be bundled, or the plate shape memory alloy 10 may be arranged at regular intervals as shown in FIG. 3B. At this time, if the shape memory alloy 10 has a single ring shape along the circumferential direction of the vulcanizing bladder 5, the vulcanizing bladder 5 is difficult to deform in the circumferential direction during vulcanization molding. Is not preferable. Further, as shown in the figure, the shape memory alloy 10 is not necessarily disposed on the inner surface of the vulcanizing bladder 5, and may be disposed at other positions, for example, disposed on the outer surface of the vulcanizing bladder 5. Alternatively, as shown in FIG. 4, the vulcanization bladder 5 may be disposed.

  Further, in the illustrated example, the shape memory alloy 10 is used as the shape memory material. However, the shape memory material 10 is limited to this as long as the material has a property of recovering to a preset shape at the heating temperature at the time of vulcanization molding. It is not something. The shape memory alloy 10 is generally an alloy of titanium and nickel, but is manufactured from various materials such as an iron-manganese-silicon alloy (iron-based shape memory alloy). Further, when the composition of the metal constituting the shape memory alloy 10 is changed, the temperature recovered by heating (the transformation point for martensitic transformation) changes. Therefore, it is preferable to appropriately change the composition of the shape memory alloy 10 in accordance with the vulcanization temperature when the green tire 2 is vulcanized.

  Note that the above description shows only a part of the embodiment of the present invention, and these configurations can be combined with each other or various modifications can be made without departing from the gist of the present invention. . For example, in the illustrated example, the shape memory alloy 10 is disposed in a region where the shape memory alloy 10 abuts from the end portion 8 of the tread portion 7 of the tire 6 to the sidewall portion 9, but the shape of the mold 3 is vulcanized. Depending on the shape of the green tire 2 and the shape of the vulcanizing bladder 5, the pressure pattern applied to the inner surface of the green tire 2 during vulcanization molding differs. Corresponding to the shape of the tire 2 and the shape of the vulcanizing bladder 5, it is possible to appropriately change the arrangement position and the deformed shape of the shape memory alloy 10. It is also possible to pressurize the tire inner surface more strongly by arranging the shape memory alloy 10 over the entire area of the vulcanizing bladder 5 and controlling the vulcanizing bladder to expand properly over the entire area of the inner surface of the tire. It is. Furthermore, although the vulcanization molding method of the green tire 2 has been described so far, this can also be applied to the vulcanization process of the base tire and the pre-cured tread when the retread tire is manufactured.

  As is apparent from the above description, the present invention can provide a vulcanizing bladder that can improve the quality of a vulcanized product tire. It has also become possible to provide a raw tire vulcanization molding method using such a vulcanization bladder.

(A)-(d) is the figure which showed the vulcanization molding method of the green tire using the conventional bladder for vulcanization | cure. (A)-(d) is the figure which showed the vulcanization molding method of the green tire using the bladder for vulcanization | cure according to this invention. (A) And (b) is a cross-sectional perspective view of the bladder for vulcanization | cure according to this invention. It is sectional drawing of the other bladder for vulcanization | cure according to this invention.

Explanation of symbols

1 Vulcanizer 2 Raw tire 3 Mold 4 Bladder ring 5 Vulcanization bladder 6 Tire (product tire)
7 Tread 8 End of the tread (hump)
9 Side wall part 10 Shape memory alloy

Claims (5)

In a vulcanizing bladder that presses the tire against the mold by sandwiching the tire between the mold and inflating,
The vulcanizing bladder is characterized in that the vulcanizing bladder has a shape correcting portion made of a shape memory material that recovers in the temperature range of the vulcanization molding.   The vulcanization bladder according to claim 1, wherein the shape memory compensation portion is disposed only in a region that abuts from an end portion of a tire tread portion to a sidewall portion.   The vulcanization bladder according to claim 1, wherein the shape memory material is recovered in the expansion direction of the vulcanization bladder.   The vulcanization bladder according to any one of claims 1 to 3, wherein the shape memory material is a shape memory alloy. When vulcanizing and molding tires,
A process of housing the tire in a mold;
Arranging a vulcanizing bladder having a shape memory material that is deformed during vulcanization molding according to any one of claims 1 to 4 on the inner surface side of the tire;
A method for vulcanizing and molding a tire, comprising: inflating the vulcanization bladder and correcting the shape with a shape memory material, pressing the inner surface of the tire and vulcanizing and molding the tire.

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