JP6790599B2 - Tire vulcanization bladder and tire manufacturing method using it - Google Patents

Description

The present invention relates to a tire vulcanization bladder used in a tire vulcanization step and a tire manufacturing method using the same. More specifically, the present invention can be removed from a tire without increasing the cost or reducing the workability. The present invention relates to a tire vulcanization bladder that can be stably implemented and a tire manufacturing method using the same.

In the process of vulcanizing a pneumatic tire, a bladder is placed inside the green tire, and the bladder is filled with a heating and pressurizing medium to press the green tire against the molding surface of the mold and at the same time. The green tire is heated by a heating and pressurizing medium filled inside the bladder.

Since such a bladder for tire vulcanization is generally formed of butyl rubber having low air permeability, it has a property of being easily vulcanized and adhered to an inner liner layer forming the innermost surface layer of the tire. .. Therefore, the releasability when the bladder is contracted after vulcanization and taken out from the tire is poor. If the tire inner liner layer and the bladder are firmly adhered to each other after vulcanization, the tire inner liner layer may be damaged when the tire is taken out, or the workability when the tire is taken out may be deteriorated to improve productivity. Inhibit.

In order to eliminate such inconvenience, a mold release agent has been conventionally applied to the inner surface of a green tire or the outer surface of a bladder, but the mold release effect lasts for a long time just by applying the mold release agent. Therefore, it is necessary to apply a release agent every time vulcanization is performed, and the influence on workability and work environment is regarded as a problem.

Further, a release layer is formed by applying a release agent such as silicone to the outer surface of the bladder, drying and curing it, but the durability of such a release layer is also insufficient. Yes, it has not yet reached a fundamental solution to the problem.

On the other hand, it is conceivable that the tire vulcanization bladder itself is formed of a silicone rubber or the like that does not vulcanize and adhere to the inner liner layer. However, since steam is generally used as the heating and pressurizing medium to be filled in the bladder, it is not practical for a tire vulcanization bladder made of silicone rubber or the like because deterioration due to hydrolysis progresses rapidly.

Further, it has been proposed to solve the above problem by making the tire vulcanization bladder a multi-layer structure and integrally providing a release layer made of silicone rubber or the like on the outer surface of the conventional bladder (for example, a patent). Refer to Documents 1 to 3). However, when the multilayer rubber layers are integrally molded, the manufacturing process of the tire vulcanization bladder becomes complicated, and the manufacturing cost thereof increases significantly.

Further, a tire vulcanization bladder having a multi-layer structure is composed of an inner bladder located inside and an outer bladder made of a material independent of the inner bladder and having excellent releasability, and these inner bladder and outer bladder. A structure has been proposed in which the clamp portions formed on both bladder are integrally gripped in a state where the bladder is laminated (see, for example, Patent Document 4). However, in this case, when the tire vulcanizer having a multi-layer structure is mounted on the vulcanizer, it is necessary to integrally grip the clamp portions of the two vulcanizers in a state of being overlapped with each other. There is a problem that the work becomes complicated. Moreover, there is a problem that the air that has entered between the layers during the assembly of the bladder is difficult to escape, and the residual air affects the degree of vulcanization and deteriorates the tire quality.

Japanese Unexamined Patent Publication No. 2011-161766 Japanese Unexamined Patent Publication No. 2012-101389 Japanese Unexamined Patent Publication No. 2014-121847 Japanese Unexamined Patent Publication No. 2005-66848

An object of the present invention is to provide a tire vulcanization bladder capable of stably performing mold release from a tire without increasing costs and reducing workability, and a tire manufacturing method using the same. is there.

The tire vulcanization bladder of the present invention for achieving the above object is a tire vulcanization bladder used in a tire vulcanization step, in which a cylindrical film portion and clamp portions formed at both ends of the film portion are formed. A bladder main body having the above, a cylindrical cover member independent of the bladder main body and laminated on the outer peripheral surface of the film portion at a position separated from the clamp portion, and the bladder main body and the cover member. and a restraining member for restraining each other in a non-adhesive state, the cover member is characterized in being composed of a material having releasability with respect to the tire innerliner layer.

Further, the tire manufacturing method of the present invention for achieving the above object is a tire manufacturing method using the tire vulcanization bladder, in which a green tire is inserted into a mold and the inside of the green tire is described. The tire vulcanization bladder composed of the bladder main body and the cover member is inserted, and the green tire is vulcanized in a state where the heat and pressure medium is filled inside the tire vulcanization bladder. It is a thing.

In the present invention, the tire vulcanization bladder is provided with a bladder body and a cover member, and the cover member is made of a material having releasability with respect to the tire inner liner layer, whereby the releasability of the cover member can be achieved. Based on this, it becomes possible to stably release the tire vulcanization bladder from the tire.

In addition, a conventional bladder can be used as the bladder body, and a cover member may be added to the bladder body, so that an increase in manufacturing cost of a tire vulcanization bladder can be minimized. it can.

In addition, the cover member has a cylindrical shape that is laminated on the outer peripheral surface of the film portion at a position separated from the clamp portion of the bladder body, and has a structure that does not have the clamp portion itself, so that the bladder replacement work can be performed. It's easy. Moreover, even if air remains between the cover member and the bladder body, the air is easily discharged from the layers between the cover member and the bladder body when the internal pressure is filled during vulcanization, so that the air remains between the layers. It is possible to prevent deterioration of tire quality due to vulcanized air.

Further, according to the present invention, since the cover member is independent of the bladder body, each of the bladder body and the cover member can be replaced at a required cycle, and each member can be effectively used. is there.

In the present invention, it is preferable to provide a restraining member that restrains the bladder body and the cover member from each other in a non-adhesive state. As a result, the integrity between the bladder body and the cover member can be ensured, and the tire vulcanization process can be smoothly performed. As such a restraining member, a pair of hook-and-loop fasteners or a pair of mechanical fasteners may be used.

It is preferable that the initial inner diameter of the cover member at an arbitrary position is smaller than the initial outer diameter at the corresponding position of the bladder body, and the permanent strain of the cover member is smaller than the permanent strain of the bladder body. By making the initial inner diameter of the cover member at an arbitrary position smaller than the initial outer diameter at the corresponding position of the bladder body, the integrity between the bladder body and the cover member is ensured and the tire vulcanization process is smoothly performed. be able to. Further, by making the permanent strain of the cover member smaller than the permanent strain of the bladder body, it is possible to ensure the integrity between the bladder body and the cover member even if the bladder body and the cover member repeatedly contract. The above-mentioned permanent strain means, for example, the compression permanent strain defined in JIS-K6262.

The thickness of the cover member is preferably uniform along the bladder axial direction. Further, the thickness of the cover member is preferably 1.5 mm or less. Since the cover member supports releasability, it may have a simple structure having a uniform thickness.

When manufacturing a tire using the above-mentioned tire vulcanization bladder, a green tire is inserted into a mold, and a tire vulcanization bladder composed of a bladder body and a cover member is inserted inside the green tire. The green tire is vulcanized with the heating and pressurizing medium filled inside the tire vulcanizing bladder. This makes it possible to stably release the tire vulcanizing bladder from the tire without using a mold release agent.

It is a meridian sectional view which shows an example of the bladder for tire vulcanization to which this invention is applied. It is a meridian sectional view which shows the bladder for tire vulcanization which comprises the embodiment of this invention. It is a side view which shows the tire vulcanization bladder which comprises embodiment of this invention. It is a meridian cross-sectional view which shows the bladder for tire vulcanization which comprises the other embodiment of this invention. It is a meridian cross-sectional view which shows the bladder for tire vulcanization which comprises still another Embodiment of this invention. It is a perspective view which shows the developed state of the tire vulcanization bladder which comprises still another Embodiment of this invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an example of a tire vulcanization bladder to which the present invention is applied. In FIG. 1, the bladder 10 is used in the vulcanization step of the green tire G. The bladder 10 has a cylindrical shape and is coaxially inserted inside the green tire G inserted into the mold 20. Then, by inflating the bladder 10 inside the green tire G, the green tire G functions to press against the molding surface of the mold 20. In FIG. 1, the mold 20 is composed of a lower mold 21, an upper mold 22, and a sector 23. Further, the lower end of the bladder 10 is gripped between the lower mold 21 and the lower clamp ring 24, and the upper end of the bladder 10 is gripped between the upper clamp ring 25 and the auxiliary ring 26.

2 and 3 show a tire vulcanization bladder according to an embodiment of the present invention. As shown in FIGS. 2 and 3, the bladder 10 is independent of the bladder main body 11 having a cylindrical film portion 11A and clamp portions 11B formed at both ends of the film portion 11A, and the bladder main body 11. It is provided with a cylindrical cover member 12 laminated on the outer peripheral surface of the film portion 11A at a position separated from the clamp portion 11B. The clamp portion 11B is formed thicker than the film portion 11A. The bladder body 11 is made of a rubber composition mainly composed of butyl rubber, while the cover member 12 is made of a material having releasability with respect to the tire inner liner layer. Silicone rubber is preferably used as a material having releasability with respect to the tire inner liner layer. Examples of other materials include fluororubber and the like.

When a tire is manufactured using the above-mentioned tire vulcanization bladder 10, a green tire G is inserted into a mold 20 and the tire vulcanization is composed of a bladder body 11 and a cover member 12 inside the green tire G. The bladder 10 is inserted, and the green tire G is vulcanized with the heat and pressure medium filled inside the tire vulcanization bladder 10. Then, the mold 20 is opened, the tire vulcanization bladder 10 is pulled out from the inside of the vulcanized tire, and the tire is taken out from the mold 20 to complete the tire vulcanization step.

As described above, the tire vulcanization bladder 10 includes the bladder body 11 and the cover member 12, and the cover member 12 is made of a material having releasability with respect to the tire inner liner layer. It is possible to stably release the tire vulcanizing bladder 10 from the tire based on the releasability.

Further, it is possible to use a conventional bladder as the bladder main body 11, and since it is sufficient to simply add the cover member 12 to the bladder main body 11, the increase in the manufacturing cost of the tire vulcanization bladder 10 is minimized. Can be suppressed. That is, unlike the case where the multi-layer rubber layer is integrally molded, the manufacturing process of the bladder main body 11 and the cover member 12 constituting the tire vulcanization bladder 10 is simple.

Further, the cover member 12 has a cylindrical shape locally laminated on the outer peripheral surface of the film portion 11A at a position separated from the clamp portion 11B of the bladder main body 11, and has a structure itself having no clamp portion. Therefore, the bladder replacement work is easy. That is, unlike the structure in which the clamp portions formed on both bladder are integrally gripped in the state where the two bladder are laminated, only the clamp portion 11B of the bladder body 11 can be attached to the vulcanizer. Because it is good, its replacement work is easy. Moreover, even if air enters between the cover member 12 and the bladder body 11, the air is easily discharged from the layers between the cover member 12 and the bladder body 11 when the internal pressure is applied during vulcanization. , It is possible to prevent deterioration of tire quality due to air remaining between layers.

Further, since the cover member 12 is independent of the bladder body 11, each of the bladder body 11 and the cover member 12 can be replaced at a required cycle, and the members 11 and 12 can be effectively used. Is. That is, in the case of a bladder having a multilayer structure in which the butyl rubber layer and the release layer are integrally molded as in the conventional case, when either the butyl rubber layer or the release layer reaches the end of its life, the entire bladder is replaced. Although it is necessary, when the bladder main body 11 and the cover member 12 are made independent, each of the bladder main body 11 and the cover member 12 can be used up to the life limit.

In the above-described embodiment, for example, it is desirable that the initial inner diameter of the cover member 12 at an arbitrary position is set to be smaller than the initial outer diameter of the bladder body 11 at a corresponding position. For example, at the axial center position of the bladder 10, the initial inner diameter of the cover member 12 is preferably smaller than the initial outer diameter of the bladder main body 11. By making the initial inner diameter of the cover member 12 at an arbitrary position smaller than the initial outer diameter of the bladder main body 11 at the corresponding position, the integrity between the bladder main body 11 and the cover member 12 is ensured, and the tire vulcanization step. Can be done smoothly. That is, even if the bladder main body 11 and the cover member 12 are not fixed to each other, misalignment is unlikely to occur between them.

Further, it is desirable that the materials of the bladder body 11 and the cover member 12 are selected so that the permanent strain of the cover member 12 is smaller than the permanent strain of the bladder body 11. By making the permanent strain of the cover member 12 smaller than the permanent strain of the bladder main body 11, even if the bladder main body 11 and the cover member 12 repeatedly contract, the integrity between the two can be ensured.

FIG. 4 shows a tire vulcanization bladder according to another embodiment of the present invention. In FIG. 4, the tire vulcanization bladder 10 includes, in addition to the bladder main body 11 and the cover member 12, a restraining member 13 that restrains the bladder main body 11 and the cover member 12 to each other in a non-adhesive state. The restraint member 13 is composed of a pair of hook-and-loop fasteners 13A and 13B that can be engaged with each other. As a result, the misalignment between the bladder main body 11 and the cover member 12 can be prevented, and the unity between the two can be ensured. Further, since the surface fasteners 13A and 13B are restrained in a non-adhesive state, the bladder main body 11 and the cover member 12 can be separated as necessary.

The pair of surface fasteners 13A and 13B constituting the restraint member 13 can be installed at any position on the tire vulcanization bladder 10. For example, in FIG. 4, a pair of surface fasteners 13A and 13B are arranged at the axial center and both ends of the bladder body 11, respectively. It is desirable that the surface fasteners 13A and 13B have elasticity by themselves. Further, it is desirable that the surface fasteners 13A and 13B are arranged so as to be scattered along the circumferential direction of the bladder main body 11. In particular, it is preferable to reduce the area of each fastener 13A and 13B so as not to hinder the expansion and contraction of the bladder body 11 and the cover member 12, increase the number of fasteners 13A and 13B according to the required engaging force, and disperse them. .. For example, the area of each fastener 13A and 13B is preferably 100 mm ² or less.

The fasteners 13A and 13B can be fixed to the surfaces of the bladder body 11 and the cover member 12 with an adhesive, but are fixed by using a suture member such as a suture or a locking member such as a staple. Is also possible. It is also possible to fix the fasteners 13A and 13B to the surfaces of the bladder body 11 and the cover member 12 by vulcanization adhesion.

The configurations of the fasteners 13A and 13B are not particularly limited, and for example, one provided with a sheet-shaped base material and a plurality of engaging elements formed on one surface of the base material can be used. it can. Further, the shape of each engaging element is not particularly limited, and for example, a hook-shaped or loop-shaped engaging element can be adopted.

FIG. 5 shows a tire vulcanization bladder according to still another embodiment of the present invention. In FIG. 5, the tire vulcanization bladder 10 includes, in addition to the bladder main body 11 and the cover member 12, a restraining member 14 that restrains the bladder main body 11 and the cover member 12 to each other in a non-adhesive state. The restraint member 14 is composed of a pair of mechanical fasteners 14A and 14B that are detachable from each other. As a result, the misalignment between the bladder main body 11 and the cover member 12 can be prevented, and the unity between the two can be ensured. Further, since the mechanical fasteners 14A and 14B are restrained in a non-adhesive state, the bladder main body 11 and the cover member 12 can be separated as necessary.

The pair of mechanical fasteners 14A, 14B constituting the restraint member 14 means those having a mechanical connection structure that allows repeated connection and separation. Typical examples are mechanical fasteners called hooks or snaps, and in the clothing industry, more specifically, snap buttons, ring snaps, ring hooks, American snaps, American hooks, eyelet hooks, spring hooks, etc. Or, it is called a jumper hook. Also, mechanical fasteners 14A, 14B are coupled portions small area (e.g., preferably 1mm ² ~115mm ^2, more preferably 4mm ² ~90mm ²⁾ is a is a point-like fasteners.

The mechanical fasteners 14A and 14B can be directly fixed to the surfaces of the bladder main body 11 and the cover member 12 by using an adhesive, but the mechanical fasteners 14A and 14B are attached to a base material such as a rubber sheet. It is also possible to fix the 14B and fix the base material to the surfaces of the bladder main body 11 and the cover member 12 by using a suture member such as a suture or a locking member such as a staple. It is also possible to fix the base material provided with the mechanical fasteners 14A and 14B to the surfaces of the bladder main body 11 and the cover member 12 by vulcanization adhesion.

FIG. 6 shows a tire vulcanization bladder according to still another embodiment of the present invention. In FIG. 6, the tire vulcanization bladder 10 is depicted so that its circumferential direction C follows a straight line for convenience. As shown in FIG. 6, a plurality of grooves 15 extending in the circumferential direction of the bladder are formed on the outer surface of the bladder main body 11, and a plurality of protrusions extending in the circumferential direction of the bladder are formed on the inner surface of the cover member 12. Article 16 is formed. Then, in a state where the cover member 12 is laminated on the outside of the bladder main body 11, the ridge 16 of the cover member 12 is fitted into the groove 15 of the bladder main body 11. According to such a configuration, the misalignment between the bladder main body 11 and the cover member 12 can be prevented, and the unity between the two can be ensured.

In each of the above-described embodiments, the thickness of the cover member 12 is preferably uniform along the bladder axial direction. Further, the thickness of the cover member 12 is preferably 1.5 mm or less. Since the cover member 12 supports releasability, a simple structure having a uniform thickness may be used. If the cover member 12 is too thick, the expansion and contraction characteristics and heat conduction characteristics required for the tire vulcanization bladder 10 will deteriorate. On the other hand, the thickness of the film portion 11A of the bladder body 11 is preferably uniform along the bladder axial direction, and for example, the thickness may be in the range of 2 mm to 30 mm.

10 Bladder 11 Bladder body 11A Membrane part 11B Clamp part 12 Cover member 13, 14 Restraint member 13A, 13B Hook-and-loop fastener 14A, 14B Mechanical fastener 15 Groove 16 Protrusion

Claims (7)

In a tire vulcanization bladder used in a tire vulcanization step, a bladder main body having a cylindrical film portion and clamp portions formed at both ends of the film portion, and the clamp independent of the bladder main body. includes a cylindrical cover member at a position deviated from the parts are stacked on the outer peripheral surface of the membrane portion, and a restraining member for restraining each other and the cover member and the bladder body in a non-adhesive state, said cover member A tire vulcanization bladder characterized by being composed of a material having releasability with respect to the tire inner liner layer. The bladder for tire vulcanization according to claim 1 , wherein the restraining member is a pair of hook-and-loop fasteners. The bladder for tire vulcanization according to claim 1 , wherein the restraining member is a pair of mechanical fasteners. The claim is characterized in that the initial inner diameter of the cover member at an arbitrary position is smaller than the initial outer diameter of the bladder body at the corresponding position, and the permanent strain of the cover member is smaller than the permanent strain of the bladder body. The bladder for tire vulcanization according to any one of 1 to 3 . The tire vulcanization bladder according to any one of claims 1 to 4 , wherein the thickness of the cover member is uniform along the bladder axial direction. The tire vulcanization bladder according to any one of claims 1 to 5 , wherein the thickness of the cover member is 1.5 mm or less. A tire manufacturing method using the tire vulcanization bladder according to any one of claims 1 to 6 , wherein a green tire is inserted into a mold, and the bladder body and the cover member are formed inside the green tire. A tire manufacturing method, characterized in that a tire vulcanizing bladder comprising the above tire is inserted, and the green tire is vulcanized in a state where the inside of the tire vulcanizing bladder is filled with a heating and pressurizing medium.

Images