JP2008126509A - Bladder, bladder apparatus and adhesion preventing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove, in taking out a tire after the vulcanization molding from the bladder, the adhesion between the bladder and the tire by using air and prevent the deformation due to the adhesion. <P>SOLUTION: On the surface of the bladder 10 for molding a raw tire there are formed many grooves 12 whose developed shapes make a V-shape, spiral shape, lattice-like shape or the like. After the completion of the vulcanization molding and before the shrink of the bladder a pressurized air is brown into the grooves 12 of the bladder 10 from the vacuum-destroying air supply pipe 30, and the raw tire 20 is positively released from the surface of the bladder 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bladder for preventing close contact of a raw tire, a bladder apparatus, and a close contact preventing method using the bladder.

  Conventionally, in tire production, a cylindrical unvulcanized tire (raw tire) is sandwiched between molds and inflated and deformed in a toroidal shape, and vulcanized while being heated from the inner and outer peripheral sides of the tire. Has been done.

  Such a tire vulcanization molding apparatus is generally composed of a central mechanism for mounting a raw tire and a mold that is disposed on the outer periphery of the central mechanism and molds the raw tire into a predetermined shape. Is provided with a rubber bag called a bladder for inflating the green tire in a toroidal shape.

At the time of vulcanization molding, a raw tire is attached to the central mechanism, and then a high-temperature and high-pressure vulcanizing medium is supplied into the bladder, whereby the bladder and the raw tire are integrally expanded and deformed in a toroidal shape. That is, the raw tire is vulcanized and molded while being pressed against the inner surface of the mold through the bladder by high-temperature steam and high-pressure inert gas supplied into the bladder.
After vulcanization, the mold is removed, and the bladder is contracted to remove the vulcanized tire from the vulcanization molding apparatus.

By the way, when using a bladder having a smooth surface, such as a conventional molded shaping bladder, the inner surface of the raw tire and the bladder surface may be in close contact with each other and deformed when a tire having a high height is taken out.
Therefore, on the inner surface of the raw tire to be vulcanized or the surface of the bladder, a silicone emulsion or the like is used for the purpose of improving the lubricity and releasability of the inner surface of the raw tire and the bladder and eliminating the occurrence of tire vulcanization defects. The release agent which consists of is performed (for example, refer patent document 1, patent document 2, patent document 3).

For tires with high height, such as SUV, when removing the tire from the molded bladder, the foot width (distance between the tire beads) is narrowed to make it easy to peel off, or the exhaust time of the bladder internal pressure is reduced. Operations such as adjusting and facilitating peeling are performed.
Here, SUV is an abbreviation for “Sport Utility Vehicle”. Since SUV has a relatively large body size and a high output engine is adopted to improve maneuverability, it is attached to this SUV. The tire needs to transmit a high driving force to the road surface due to a large outer diameter or the like, and the rigidity of the tire is enhanced because the steering stability such as turning performance is sufficiently required.

In such a high-tyre tire such as SUV having a certain degree of longitudinal rigidity, it could be extracted without being in close contact with a combination of a conventional bladder or extraction operation.
However, in the future, it is thought that the side tread will be made thinner because of cost reduction and weight reduction. As the side tread is made thinner, the longitudinal rigidity of the tire will decrease. It is expected that extraction by the conventional method that has been performed on the premise that it is somewhat strong will be difficult.

In addition, in the case of a structure that requires the drum to be rotated when the foot width is moved, when the tire is taken out, the drum is rotated by gripping the tire from the outside. It is impossible to plan.
JP-A-5-301229 JP 2002-1279 A JP-A-9-323323

  The present invention has been made in view of the above-described conventional problems, and its purpose is to provide a tire with low longitudinal rigidity corresponding to the thin gauge of the side tread that tends to have low longitudinal rigidity. It is to prevent it from coming into close contact with the surface of the bladder during removal.

The invention of claim 1 is characterized in that a plurality of grooves for introducing a vacuum breaking medium with the green tire are formed on the surface of the bladder that contacts the back surface of the green tire during molding.
According to a second aspect of the present invention, in the bladder according to the first aspect, the groove bottom shape of the groove is round or square.
According to a third aspect of the present invention, in the adhesion preventing bladder according to the first or second aspect, the groove is formed of a straight line, a curved line, or a combination thereof extending from both ends of the raw tire contact surface of the bladder toward the center. It is characterized by that.
Invention of Claim 4 is a bladder apparatus, Comprising: The vacuum fracture | rupture for introduce | transducing the vacuum fracture | rupture medium into the contact surface of the bladder described in any one of Claim 1 thru | or 3, and the said bladder and a green tire Medium supply means.
The invention according to claim 5 is a method for preventing adhesion between the inner surface of the green tire molded by the bladder and the surface of the bladder, and the raw tire is vulcanized using the bladder according to claim 3. And a step of introducing a vacuum breaking medium into the groove of the bladder.

According to the present invention, since the tire after vulcanization molding can be forcibly separated by blowing a vacuum breaking medium onto the surface of the bladder that contacts the inner surface of the raw tire, Can be completely prevented from sticking to the bladder when the tire is removed.
In addition, a bladder device capable of preventing adhesion can be obtained at a low cost with a simple configuration.

1A to 1C are views showing development views according to embodiments having different groove shapes on the surface of the bladder according to the embodiment of the present invention.
In the embodiment of FIG. 1A, the grooves are formed on the surface of the bladder 10 that is in contact with the inner surface of the raw tire 20 as shown in the drawing, and a plurality of parallel linear grooves that are inclined upward from both ends toward the center. It is formed as. With the groove formed in this way, the vacuum breaking medium introduced from the outside, for example, air, flows into the center of the tire when the vulcanized tire is extracted from the bladder with the raw tire vulcanized. Then, the vacuum generated between the tire inner surface and the bladder surface can be broken to completely eliminate the adhesion.

  In the embodiment of FIG. 1B, the groove extends spirally from the center as shown. In this shape, the air flow path length to the groove end on the center side is longer than that of the straight groove in FIG. 1A, and the vacuum breaking ability is improved accordingly.

In the embodiment of FIG. 1C, the grooves are in the form of a lattice as shown, and the flow path length of the entire groove is longer than that of FIG. 1B, and is approximately twice that of FIG. 1A. Therefore, the vacuum breaking ability is further improved.
In addition, if the expansion | deployment shape of a groove | channel can introduce air toward the center part from the both ends of the bladder 10 with which the bladder 10 and the raw tire 20 closely_contact | adhere, it is not limited to the above thing, A straight line, a curve, or those Any of these combinations may be used.

  The groove bottom of the groove is preferably formed as wide as possible so that as much air as possible can be circulated, that is, the cross-sectional area of the groove is increased or the flow resistance is reduced. Square, round and round are preferred.

FIG. 2 is a cross-sectional view schematically showing a portion of the bladder device excluding the mold for positively removing the adhesion between the inner surface of the molded tire 20 and the surface of the bladder 10 performed after vulcanization molding.
As shown in the drawing, the bladder 10 is inflated and is in close contact with the raw tire 20 while being supported by the conventional central mechanism S. Also, a plurality of pipes 30 (vacuum) provided with air outlets (nozzles) as air supply means in the vicinity of the boundary between the both sides of the bladder 10 and the raw tire 20 and connected to a pressurized air supply source (not shown). Breaking air supply pipes) are arranged along the boundary portion, that is, circumferentially at equal intervals.

In this state, when the pressurized air is sprayed from the air outlets arranged on both sides of the bladder 10 to the close end portion between the raw tire 20 and the bladder 10, the air flows into the groove 12 of the bladder 10, While peeling the joint surface of the bladder 10 and the green tire 20 along the groove 12, that is, vacuum breaking, it flows toward the center portion.
The air that has reached the center flows out while spreading between the peeled surface of the bladder 10 and the inner surface of the green tire 20.

According to the present embodiment, by blowing air between the bladder 10 and the raw tire 20, the vacuum generated between the bladder 10 and the raw tire 20 during vulcanization molding is actively broken, Adhesion with the raw tire 20 can be eliminated.
This close contact removal has a simple structure in which a plurality of grooves are formed on the surface of the conventional bladder 10 from both left and right end portions to the center portion, and pressurized air is blown toward the grooves, which requires much cost. Can be implemented without.

1A-1C show an embodiment of a bladder with different deployment groove shapes. It is sectional drawing which shows the bladder apparatus except a metal mold | die roughly.

Explanation of symbols

10 ... Bladder, 12 ... Groove, 20 ... Green tire, 30 ... Air supply pipe for vacuum break.

Claims (5)

  A bladder characterized in that a plurality of grooves for introducing a medium for vacuum breakage with a raw tire are formed on the surface of the bladder that comes into contact with the back of the raw tire during molding. The bladder of claim 1,
The bladder characterized in that the groove bottom shape of the groove is round or square. The adhesion preventing bladder according to claim 1 or 2,
The said groove | channel consists of the straight line or curve which extends toward the center from the both ends of the raw tire contact surface of a bladder, or its combination, The bladder characterized by the above-mentioned. A bladder according to any one of claims 1 to 3;
A bladder apparatus comprising: a vacuum breaking medium supply means for introducing a vacuum breaking medium into a contact surface between the bladder and the green tire. A method for preventing adhesion between an inner surface of a green tire molded by a bladder and a bladder surface,
After the raw tire is vulcanized and molded using the bladder according to claim 3, the tire inner surface and the bladder surface are provided with a step of introducing a vacuum breaking medium into the groove of the bladder. Adherence prevention method.

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