WO2006033364A1

WO2006033364A1 - Vulcanization device and method

Info

Publication number: WO2006033364A1
Application number: PCT/JP2005/017405
Authority: WO
Inventors: Ryusaku Obuchi
Original assignee: Bridgestone Corporation
Priority date: 2004-09-22
Filing date: 2005-09-21
Publication date: 2006-03-30
Also published as: JP2006088472A

Abstract

High temperature and high pressure are applied, in an initial stage of core vulcanization, to a rubber material forming a raw tire to firmly join the interface of a rubber layer. A vulcanization device comprises a tread forming die (2) for defining the outer surface shape of a tire (10), upper and lower side dies (3, 4), and an inner die (5) for defining the inner surface shape of the tire (10). The raw tire (10) is molded and vulcanized in a cavity defined by the dies (2-4) and the inner die (5). The inner die (5) is provided, on the outer surface thereof, with a stretchable thin film (14) of an elastic body, and the raw tire (10) is expanded by heating and pressurized at the time of vulcanization by using noncompressive heating/pressurizing fluid that is fed between the outer surface (5) of the inner die (5) and the thin film (14).

Description

Specification

Vulcanizing apparatus and vulcanizing method

Technical field

The present invention includes an outer mold that defines an outer shape of a tire and an inner mold that defines an inner shape of the tire, and pressurizes and heats a raw tire formed on the inner mold during vulcanization. The present invention relates to a vulcanizing apparatus and a vulcanizing method.

Background art

[0002] As a method for vulcanization molding of rubber products, for example, tires, a so-called core vulcanization molding method is known in which a tire is vulcanized in a space formed by an outer mold and an inner mold. (For example, see Patent Document 1).

In order to vulcanize and mold a tire by this core vulcanization molding method, first, a rubber material such as a carcass ply, a belt, and a tread rubber is sequentially pasted or wound on a main body portion of an inner mold. The inner mold with the green tire formed in this way is set in the outer mold, and a vulcanization molding is performed by enclosing or circulating a pressurized heating medium such as hot air in the inner mold. Do.

[0003] Here, in the method of heating the inner mold with hot air or the like, the heat exchange efficiency between the hot air and the inner mold, which is a metal material (for example, aluminum based alloy), is low. There is a problem that it takes time to heat up the mold. In particular, in the core vulcanization method in which the vulcanization pressure is obtained by the thermal expansion of the tire, in the initial stage of heating the inner mold, the raw tire is not heated to the extent that it thermally expands. Has a pressure pattern in which the pressure shifts to high pressure as the temperature of the green tire rises as time passes (see Figure 2 below).

[0004] In such a core vulcanization molding method, high pressure is generated after the middle vulcanization stage. Therefore, at this stage, the green tire is completely in close contact with the surface in the outer mold. There is a possibility that the vulcanization reaction has almost been completed from the outer surface side of the raw tire, and when the pressure is generated, the rubber of the green tire is no longer in the plastic deformation region to the elastic deformation region. Therefore, the interface between the laminated ribbon layers is not sufficiently bonded, and the ribbon layer interface may be separated, resulting in a deterioration in quality. For compressible fluids such as hot air, the pressure There is a problem that force and temperature cannot be freely controlled individually.

Patent Document 1: JP 2000-141380 A

Disclosure of the invention

Problems to be solved by the invention

[0005] The present invention has been made to solve the above-mentioned conventional problems in the inner mold vulcanization molding, and its purpose is to freely control the pressure and temperature of the pressurizing and heating medium to increase the pressure. At the initial stage of the sulfur reaction, high temperature and high pressure are applied to the green tire to ensure adhesion between the interfaces of the laminated rubber layers and to prevent separation of the ribbon layer, thereby improving quality. It is.

Means for solving the problem

[0006] The invention of claim 1 includes an outer mold that defines the outer surface shape of the tire and an inner mold that defines the inner surface shape of the tire, and the raw tire is formed by the outer mold and the inner mold. A vulcanization mold for forming a toroidal cavity for vulcanization molding is provided, and the inner mold has a stretchable film body on its outer surface, and the inner mold outer surface and the aforementioned mold It is characterized in that means for supplying a pressurized fluid for pressing the green tire against the outer mold is provided between the film bodies.

The invention according to claim 2 is the vulcanizing apparatus according to claim 1, wherein the pressurized fluid is an incompressible fluid whose pressure and temperature can be controlled independently and is heated to a predetermined temperature. It is characterized by.

According to a third aspect of the present invention, in the vulcanizing apparatus according to the first or second aspect, the means for supplying the pressurized fluid applies pressurized fluid recirculated from between the outer surface of the inner mold and the film body. Characterized by pressure / heating means!

The invention according to claim 4 is the vulcanizing apparatus according to any one of claims 1 and 3, wherein the green tire is formed by ribbon-wrapping a rubber material layer on an inner mold. It is characterized by that.

The invention of claim 5 includes a step of forming a green tire on the inner mold, a step of accommodating the inner mold in the outer mold, an outer surface of the inner mold, and an expansion / contraction attached to the outer surface. Supplying a pressurized fluid having a predetermined pressure between the flexible film body and the incompressible fluid. And a step of pressing the gear against the outer mold.

The invention of claim 6 is the vulcanization molding method according to claim 5, wherein the pressurized fluid is an incompressible fluid whose pressure and temperature can be controlled independently and is heated to a predetermined temperature. It is characterized by that.

[0007] (Function)

In the present invention, by using an incompressible fluid as the heating and pressurizing medium, heat exchange with the inner mold is improved, the inner mold is efficiently heated, and the outer surface of the inner mold has heat resistance and Equipped with a stretchable membrane body, and during vulcanization, the incompressible fluid in which the heat and pressure are independently controlled to a predetermined value is transferred from the inside mold membrane to the inside mold membrane. The raw tire is pressurized at a predetermined pressure in the vulcanizing mold from the initial stage of vulcanization and maintained at the predetermined pressure. In addition, by using an incompressible fluid instead of hot air, the efficiency of heat exchange with the metal inner mold is increased, and the inner mold is heated faster.

The invention's effect

[0008] In the present invention, a predetermined pressure and temperature can be applied to a raw tire at the initial stage of vulcanization. Therefore, during the vulcanization reaction, between the interfaces of the laminated rubber material layers constituting the raw tire. A high pressure can be applied to improve the adhesiveness, and a tire with excellent quality performance can be provided without rubber material peeling off at the interface.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] An embodiment of the present invention will be described with reference to the drawings.

Fig. 1 shows a cross-sectional view of a vulcanization mold of a vulcanizer.

The vulcanizing mold 1 includes a tread forming mold 2 constituting an outer mold, an upper side mold 3 and a lower side mold 4 arranged above and below the tread forming mold 2, It consists of a tread forming mold 2 and a toroidal inner mold 5 accommodated in a recess formed by upper and lower side molds 3 and 4, and each of these when the outer and inner molds are closed. A toroid-like cavity is formed with a mold, and the green tire 10 is vulcanized and molded in this cavity.

[0010] The tread forming mold 2 is formed of a rigid body such as an aluminum base material or an iron base material, and has a molding surface for forming the outer shape of the tread portion 11 of the tire 10, and inside and outside in the radial direction thereof. Transfer It consists of many movable segments, and these segments form a ring as a whole.

[0011] The upper and lower side molds 3, 4 are made of a rigid body such as an aluminum base material or an iron base material, and have molding surfaces for forming the outer surface shape of the sidewall portion 12 of the tire 10. At least one of the side molds 3 and 4 is configured to be movable in the mold opening direction so that the raw tire can be inserted into the cavity and the vulcanized tire can be taken out. .

[0012] The inner mold 5 is a toroid-shaped metal rigid body such as an aluminum base material or an iron base material, and has a molding surface for forming the inner surface shape of the tire 10, and the outer surface of the inner mold 5 An elastic thin film 14 having heat resistance and elasticity, such as synthetic rubber, polyethylene terephthalate, etc., is attached to the body.

Further, in the space between the elastic thin film 14 and the outer surface of the inner mold 5, an incompressible fluid such as hot water, oil or other liquid is supplied through the inner mold 5 as a heating and pressurizing medium. It is done.

FIG. 2 is a diagram showing a change in pressure acting on the tire during vulcanization in comparison with the conventional one.

As is clear from FIG. 2, in the vulcanizing apparatus equipped with the conventional vulcanizing mold, the inner mold 5 is heated with hot air, and the raw tire is thermally expanded by the heat conduction from the inner mold 5 to tread. Since the forming mold 2 and the upper and lower side molds 3 and 4 are pressurized, there is a time lag until the vulcanization start force green tire is heated and expanded and the pressure reaches a predetermined value, causing the above-mentioned problems.

On the other hand, in the vulcanizing apparatus including the vulcanizing mold 1 according to the present embodiment, the inner surface of the green tire is pressurized and pressed between the inner mold 5 and the film body, that is, the elastic body thin film 14. Since the incompressible fluid to be heated is supplied, the lower surface of the green tire is pressurized through the elastic thin film 14 simultaneously with the start of vulcanization, and the thermal expansion of the green tire due to the heating of the incompressible fluid force is added. The prescribed pressure is reached more quickly.

FIG. 3 is a diagram schematically showing a system for supplying a heating fluid into the inner mold 5. The incompressible fluid is pressurized to, for example, 1 to: LOMpa by a hydraulic pump P having an arbitrary configuration, and is heated to a predetermined temperature, for example, 373 to 473 k by the heating device 15 and is supplied from the inlet 20 to the inside. It is fed into the side mold 5.

[0016] The incompressible fluid supplied from the inside of the inner mold 5 flows between the outer surface of the inner mold 5 and the inner surface of the elastic thin film 14, and from the outlet 21 to the conduit 23, the hydraulic pump P and It passes through the heating device H and is maintained and controlled at a predetermined pressure and temperature. Thus, during vulcanization, the incompressible fluid always circulates between the outer surface of the inner mold 5 and the elastic thin film 14, while the incompressible fluid is maintained at a substantially constant pressure and temperature. Maintained.

In addition, when the interface of the rubber material layer constituting the green tire can be narrowed in the initial stage of vulcanization, the heated and pressurized incompressible fluid is not limited to the above-described configuration, and the inner mold 5 and the inner mold 5 A configuration in which sealing is performed between the outer surface and the film body (elastic thin film) 14 can also be employed.

[0017] The elastic thin film 14 expands upon receiving the pressure of the incompressible fluid, presses the back surface of the raw tire, and heats to promote thermal expansion of the raw tire. And the upper and lower side molds 3 and 4 are in close contact with the inner surface. At that time, the interfaces are joined by a compressive force acting between the ribbon layer interfaces of the laminated rubber materials constituting the green tire.

[0018] According to the present embodiment, the incompressible fluid is first used as compared with the case where the conventional hot air is sent into the inner mold by using the incompressible fluid to raise the temperature of the metal inner mold. The heat exchange between the metal mold and the metal inner mold is greatly improved, so that the temperature of the inner mold can be increased rapidly, and the heat of the incompressible fluid is transferred to the green tire through the elastic thin film 14. Therefore, the temperature of the green tire itself is quickly increased and the thermal expansion of the tire is promoted. In the first place, the non-compressed fluid is pressurized to a predetermined high pressure, so in the initial stage of vulcanization, the tire is tread-molding mold 2, upper and lower side molds 3, 4 inner surfaces at the high pressure of the uncompressed fluid. Pressed. In this way, the rubber layer interface between the tire materials constituting the green tire is strongly compressed and strongly joined during the vulcanization reaction.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of a vulcanization mold according to an embodiment of the present invention.

FIG. 2 is a diagram showing how the pressure acting on the back side of the green tire in the vulcanizing mold changes with time.

FIG. 3 is a diagram schematically showing a system for supplying an incompressible fluid to a vulcanization mold. Explanation of symbols 1 ... ······························································ Elastic thin film

Claims

The scope of the claims

[1] A toroidal mold for vulcanizing a green tire with an outer mold and an inner mold, and an outer mold that defines the outer shape of the tire and an inner mold that defines the inner shape of the tire It is equipped with a vulcanizing mold that forms a cavity,

The inner mold has a stretchable film body on its outer surface,

A vulcanizing apparatus comprising means for supplying a pressurized fluid that presses a green tire against the outer molding die between the outer surface of the inner die and the film body.

[2] In the vulcanizing apparatus according to claim 1,

The vulcanizing apparatus, wherein the pressurized fluid is an incompressible fluid whose pressure and temperature can be controlled independently and heated to a predetermined temperature.

[3] In the vulcanizing apparatus according to claim 1 or 2,

The vulcanizing apparatus is characterized in that the means for supplying the pressurized fluid comprises means for pressurizing and heating the pressurized fluid refluxed from between the outer surface of the inner mold and the film body.

[4] In the vulcanizing apparatus according to any one of claims 1! And 3!

The raw tire is formed by winding a rubber material layer on an inner mold by ribbon winding.

[5] forming a green tire on the inner mold;

Forming a toroid-like cavity for vulcanizing a green tire with the inner mold and the outer mold;

Supplying a pressurized fluid of a predetermined pressure between the outer surface of the inner mold and the inflatable membrane attached to the outer surface;

Pressing the raw tire against the outer mold with the incompressible fluid;

A vulcanization molding method comprising:

[6] In the vulcanization molding method according to claim 5,

The vulcanization molding method, wherein the pressurized fluid is an incompressible fluid whose pressure and temperature can be controlled independently and is heated to a predetermined temperature.