Tire vulcanization method and tire manufacturing method

Abstract

This invention provides a tire vulcanization method that can uniformly vulcanize tires with uneven wall thickness distribution. [Solution] The tire vulcanization method 100 includes a first vulcanization step S1 in which a heating medium containing steam is supplied to a first space between at least an outer bladder and an inner bladder to expand the outer bladder and vulcanize the unvulcanized tire, and a second vulcanization step S2 in which a pressurized medium containing an inert gas is supplied to a second space in the inner cavity of the inner bladder to expand the inner bladder, compressing the heating medium in the first space and causing the first space to be unevenly distributed within the outer bladder, thereby adjusting the distribution of heat transfer to the unvulcanized tire.

Description

Technical Field

[0001] The present invention relates to a tire vulcanization method and a tire manufacturing method.

Background Art

[0002] Conventionally, various techniques have been proposed regarding tire vulcanization. For example, Patent Document 1 discloses a technique in which a vulcanization bladder is configured with a double structure of a first bladder and a second bladder to reduce the amount of drain generated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the wall thickness distribution of a tire is not constant. Generally, the thickness of the tread portion is larger than that of the sidewall portion. Therefore, when the vulcanization time is set according to the tread portion, the sidewall portion becomes over - vulcanized (over - cure), and when the vulcanization time is set according to the sidewall portion, the tread portion becomes under - vulcanized (under - cure).

[0005] The present invention has been devised in view of the above actual situation, and the main object thereof is to provide a tire vulcanization method capable of uniformly vulcanizing a tire with a non - constant wall thickness distribution.

Means for Solving the Problems

[0006] The present invention is a method for vulcanizing a tire using a vulcanization mold and a bladder disposed in the inner cavity of an unvulcanized tire set in the vulcanization mold, where the bladder includes an outer bladder that contacts the unvulcanized tire and an inner bladder disposed in the inner cavity of the outer bladder. The aforementioned method, A first vulcanization step in which a heating medium containing steam is supplied to at least the first space between the outer bladder and the inner bladder to expand the outer bladder and vulcanize the unvulcanized tire, The process includes a second vulcanization step in which a pressurized medium containing an inert gas is supplied to a second space within the lumen of the inner bladder, thereby expanding the inner bladder and compressing the heating medium in the first space, causing the first space to be unevenly distributed within the outer bladder, and adjusting the distribution of heat transfer to the unvulcanized tire. [Effects of the Invention]

[0007] Because the tire vulcanization method of the present invention has the above configuration, it can uniformly vulcanize tires with an uneven thickness distribution. [Brief explanation of the drawing]

[0008] [Figure 1] This flowchart shows the procedure of one embodiment of the tire vulcanization method of the present invention. [Figure 2] This is a cross-sectional view showing the configuration of a tire vulcanization apparatus used to implement the tire vulcanization method shown in Figure 1. [Figure 3] Figure 2 is a cross-sectional view showing the outer bladder, inner bladder, and their surrounding structures. [Figure 4] This is a cross-sectional view showing a tire vulcanization apparatus in the state of the first vulcanization process. [Figure 5] This is a cross-sectional view showing a tire vulcanization apparatus in the second vulcanization process. [Figure 6] This is a cross-sectional view showing a tire vulcanizing apparatus in the stirring process. [Figure 7] Figure 1 is a flowchart showing a modified version of the tire vulcanization method. [Figure 8] This is a cross-sectional view showing a tire vulcanizing apparatus in the state of the first discharge process. [Figure 9] This is a cross-sectional view showing a tire vulcanizing apparatus in the state of the second discharge process. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. It should be understood that the drawings contain exaggerations and representations that differ from the actual dimensional ratios of the structure in order to aid in understanding the content of the invention. Furthermore, the same or common elements are denoted by the same reference numerals throughout each embodiment, and redundant explanations are omitted. Moreover, the specific configurations shown in the embodiments and drawings are for the purpose of understanding the content of the present invention, and the present invention is not limited to the specific configurations shown in the drawings.

[0010] Figure 1 is a flowchart showing the procedure of the tire vulcanization method 100 according to this embodiment. The tire vulcanization method 100 is a process of vulcanizing an unvulcanized tire that has been molded in the molding process, and is performed as part of the tire manufacturing process for manufacturing a tire.

[0011] As shown in Figure 1, the tire vulcanization method 100 of this embodiment includes a first vulcanization step S1 and a second vulcanization step S2.

[0012] Figure 2 shows a tire vulcanization apparatus 1 for carrying out the tire vulcanization method 100 of this embodiment. The tire vulcanization apparatus 1 includes a vulcanization mold 2, a vulcanization bladder 3, and a support mechanism 6.

[0013] The vulcanizing mold 2 is a mold for vulcanizing the outer surface of an unvulcanized tire T. The vulcanizing mold 2 in this example comprises a tread mold 21 for forming the tread portion of the tire, upper and lower side molds 22 and 23 for forming the sidewall portion of the tire, and upper and lower bead rings 24 and 25 for forming the bead portion of the tire. The tread mold 21 is divided into multiple sections in the circumferential direction. A molding surface 26 that contacts the outer surface of the unvulcanized tire T is formed on the inner surface of the vulcanizing mold 2.

[0014] The vulcanization mold 2 is not limited to the form illustrated in Figure 1; for example, a so-called two-piece type, which is divided into upper and lower sections, may also be used.

[0015] The vulcanizing mold 2 is heated using steam or electricity as an energy source. The heated vulcanizing mold 2 vulcanizes the unvulcanized tire T from the outside.

[0016] The vulcanizing bladder 3 is disposed in the inner cavity of the unvulcanized tire T. A heating medium and a pressurizing medium are supplied to the vulcanizing bladder 3, causing the vulcanizing bladder 3 to expand. Due to the expansion of the vulcanizing bladder 3, it comes into contact with the unvulcanized tire T and presses the unvulcanized tire T against the vulcanizing mold 2. At this time, the vulcanizing bladder 3 heated by the heating medium and the pressurizing medium vulcanizes the unvulcanized tire T from the inside.

[0017] The vulcanizing bladder 3 includes an outer bladder 4, an inner bladder 5, and supports 31, 32, 33, 34, 35, and 36. The outer bladder 4 and the inner bladder 5 are formed in a toroidal shape.

[0018] Figure 3 shows the outer bladder 4, the inner bladder 5, and the surrounding configuration.

[0019] [[ID=..]] The outer bladder 4 contacts the unvulcanized tire T loaded in the vulcanizing mold 2. The outer bladder 4 is supported by supports 31, 32, 34, 35. The inner bladder...

[0020] Supports 31, 32, 33 are driven vertically by a support mechanism 6. Support 31 abuts against and is positioned by the bead ring 24. Supports 3...

[0021] A first space SP1 filled with a heating medium, which will be described later, is partitioned by the outer bladder 4 and the inner bladder 5. The first space SP...

[0022] It seems there is an incomplete part in your original text for item 18. I've translated as much as possible with the given content. Please check and let me know if there are any corrections needed. Furthermore, the inner bladder 5 partitions a second space SP2, which is filled with a pressurizing medium described later. The second space SP2 is the space inside the inner bladder 5.

[0023] The outer bladder 4 has a main body 41 that expands and contracts in response to the rise and fall of pressure in the first space SP1. The main body 41 is made of an expandable rubber material or the like. The upper edge 41U of the main body 41 is supported by being sandwiched between supports 31 and 32. The lower edge 41L of the main body 41 is supported by being sandwiched between supports 34 and 35.

[0024] The inner bladder 5 has a main body 51 that expands and contracts in response to the rise and fall of pressure in the second space SP2. The main body 51 is made of an expandable rubber material or the like. The upper edge 51U of the main body 51 is supported by being sandwiched between supports 32 and 33. The lower edge 51L of the main body 51 is supported by being sandwiched between supports 35 and 36.

[0025] A support member 32 interposed between the edge 41U of the outer bladder 4 and the edge 51U of the inner bladder 5 has a flow path 38 that connects the internal space 37 and the first space SP1. The flow path 38 may also be formed in a support member 35 interposed between the edge 41L of the outer bladder 4 and the edge 51L of the inner bladder 5.

[0026] A support member 35 interposed between the edge 41L of the outer bladder 4 and the edge 51L of the inner bladder 5 has a flow channel 39 that communicates with the first space SP1.

[0027] The support mechanism 6 has a vertically movable center post 61 and a cylindrical portion 62 that supports the center post 61. A support member 31 is connected to the center post 61. A support member 36 is connected to the cylindrical portion 62.

[0028] The support mechanism 6 is provided with flow paths 65, 66, and 67 for supplying gas to the first space SP1 and the second space P2, and for recovering the gas from the first space SP1 and the second space P2.

[0029] The flow path 65 is provided, for example, in the center post 61 and communicates with the first space SP1 via the internal space 37 and the flow path 38. The flow path 66 is provided, for example, in the cylindrical portion 62 and communicates with the second space SP2. The flow path 67 is provided, for example, in the cylindrical portion 62 and communicates with the first space SP1 via the flow path 39.

[0030] Figure 4 shows the tire vulcanizing apparatus 1 in the state of the first vulcanization process S1. In the first vulcanization process S1, a heating medium G1 is supplied to the first space SP1 between the outer bladder 4 and the inner bladder 5. The heating medium G1 is supplied to the first space SP1 from a supply source (not shown) located outside the tire vulcanizing apparatus 1 via a flow path 65, an internal space 37, and a flow path 38. For example, the heating medium G1 is supplied to the first space SP1 by operating a valve located between the supply source of the heating medium G1 and the flow path 65.

[0031] For example, a gas containing steam is applied as the heating medium G1. Steam is suitable as the main component of the heating medium G1 because it can efficiently heat the unvulcanized tire T due to its latent heat. The heating medium G1 may also contain an inert gas such as nitrogen, argon gas, or helium.

[0032] In the first vulcanization step S1, the heating medium G1 is supplied at a first pressure P1 (for example, 1.4 MPa).

[0033] In the first vulcanization step S1, the heating medium G1 is supplied to the first space SP1, causing the outer bladder 4 to expand and come into contact with the unvulcanized tire T. Furthermore, the outer bladder 4 expands together with the unvulcanized tire T. As a result, the unvulcanized tire T is pressed against the vulcanization mold 2, and the unvulcanized tire T is vulcanized from the outside through heat exchange between the vulcanization mold 2 and the unvulcanized tire T. In addition, the unvulcanized tire T is vulcanized from the inside through heat exchange between the heating medium G1 via the outer bladder 4 and the unvulcanized tire T.

[0034] In this tire vulcanizing apparatus 1, during the first vulcanization process S1, a heating medium G1 is interposed between the inner bladder 5 and the outer bladder 4, and the entire inner bladder 5 is separated from the outer bladder 4. As a result, heat from the heating medium G1 is transferred to the entire unvulcanized tire T via the outer bladder 4, allowing the vulcanization to proceed efficiently.

[0035] In Figure 4 and Figure 5 (described later), areas where vulcanization is complete or in the process of completion are indicated by dot-like hatching.

[0036] The first vulcanization process S1 is continued in accordance with the progress of vulcanization in the thinnest part T1 of the unvulcanized tire T, for example, the region corresponding to the area from the buttress portion to the sidewall portion (more specifically, the widest part) of a vulcanized tire. Generally, the progress of vulcanization depends on the thickness of the unvulcanized rubber, and the thinnest part T1 tends to progress faster. Therefore, in this embodiment, it is desirable that the process transitions from the first vulcanization process S1 to the second vulcanization process S2 when it can be determined that the vulcanization inside the thinnest part T1 has progressed by about 40-90%.

[0037] In the first vulcanization step S1, the pressurizing medium G2 is supplied to the second space SP2 within the lumen of the inner bladder 5 so that the pressure in the first space SP1 and the pressure in the second space SP2 become equal to the first pressure P1. This maintains the shape of the inner bladder 5. The pressurizing medium G2 and the configuration for supplying the pressurizing medium G2 will be described later.

[0038] In the first vulcanization process S1, a portion of the heating medium G1 liquefies due to heat exchange with the unvulcanized tire T. At this time, the inner bladder 5 expands due to the pressure of the pressurizing medium G2, compensating for the pressure drop in the first space SP1. For this reason, in this embodiment, the pressurizing medium G2 is supplied at a first pressure P1. This makes it possible to maintain a constant pressure in the first space SP1 while saving energy by closing the valve located between the heating medium G1 supply source and the flow path 65 to stop the supply of the heating medium G1.

[0039] Figure 5 shows the tire vulcanizing apparatus 1 in the state of the second vulcanization process S2. In the second vulcanization process S2, with the supply of the heating medium G1 stopped, a pressurized medium G2 containing an inert gas is additionally supplied to the second space SP2 in the lumen of the inner bladder 5. The pressurized medium G2 is supplied to the second space SP2 via a flow path 66 from a supply source (not shown) located outside the tire vulcanizing apparatus 1. For example, the pressurized medium G2 is supplied to the second space SP2 by operating a valve located between the supply source of the pressurized medium G2 and the flow path 66.

[0040] For example, inert gases such as nitrogen, argon, and helium are used as the pressurizing medium G2. Inert gases are suitable as the main component of pressurizing medium G2 because they do not easily cause a pressure drop due to condensation.

[0041] In a typical single-layer bladder vulcanization process, the internal space of the bladder is first filled with steam, which is the heating medium G1, and then, as vulcanization progresses, it is filled with an inert gas, which is the pressurizing medium G2. However, the filling of the inert gas causes the gas molecules of steam and the gas molecules of the inert gas to mix in the internal space of the bladder, making it difficult for the steam gas molecules to collide with the bladder, and the heat of the steam tends not to be fully utilized for vulcanization of the unvulcanized tire T. However, in this embodiment, the pressure of the first space SP1 and the pressure of the second space SP2 are isolated by the inner bladder 5, so the gas molecules of the heating medium G1 do not mix with the gas molecules of the pressurizing medium G2, and only the gas molecules of the heating medium G1 exist in the first space SP1 between the outer bladder 4 and the inner bladder 5. Therefore, the heat of the heating medium G1 is fully utilized for vulcanization of the unvulcanized tire T.

[0042] In the second vulcanization step S2, pressurized medium G2 is supplied at a second pressure (e.g., 2.1 MPa) that is higher than the first pressure P1 of the heating medium G1 supplied in the first vulcanization step S1. As a result, the inner bladder 5 expands within the lumen of the outer bladder 4, compressing the heating medium G1 in the first space SP1. Consequently, the pressure in the first space SP1 becomes equal to the pressure in the second space SP2, and the first space SP1 becomes unevenly distributed within the outer bladder 4.

[0043] In the second vulcanization step S2, a portion of the heating medium G1 liquefies due to heat exchange with the unvulcanized tire T, causing a decrease in the pressure in the first space SP1. In the second vulcanization step S2 of this embodiment, the pressurizing medium G2 is supplied to the second space SP2 at a second pressure higher than the first pressure P1 of the heating medium G1. As a result, the inner bladder 5 expands, adiabatically compressing and heating the heating medium G1 in the first space SP1. This makes it possible to vulcanize the unvulcanized tire T efficiently with even less energy.

[0044] In this tire vulcanizing apparatus 1, the inner bladder 5 expands during the second vulcanization process S2, causing the first space SP1 to be unevenly distributed within the outer bladder 4, and the inner bladder 5 to partially contact the outer bladder 4. That is, a contact region CR1 is created where the inner bladder 5 is in contact with the outer bladder 4, and a non-contact region CR2 is created where the inner bladder 5 is separated from the outer bladder 4.

[0045] In the non-contact region CR2, efficient heat exchange continues between the heating medium G1 containing steam and the unvulcanized tire T via the outer bladder 4, similar to the first vulcanization step S1. On the other hand, in the contact region CR1, heat exchange occurs between the pressurizing medium G2 and the unvulcanized tire T via the inner bladder 5 and the outer bladder 4, resulting in reduced efficiency. Therefore, in the second vulcanization step S2 of this embodiment, a difference is created between the amount of heat exchanged in the non-contact region CR2 and the amount of heat exchanged in the contact region CR1, and the distribution of heat transfer from the outer bladder 4 to the unvulcanized tire T is adjusted. This makes it possible to uniformly vulcanize the unvulcanized tire T, which does not have a uniform thickness distribution.

[0046] The inner bladder 5 includes a pair of first portions 56 that face a pair of sidewall portions Ts of the unvulcanized tire T via the outer bladder 4, and a second portion 57 that faces the tread portion Tt of the unvulcanized tire T. The pair of first portions 56 and second portions 57 are formed in the main body portion 51.

[0047] In the case of an unvulcanized tire T in which the thickness of a pair of bead portions is equal to or greater than the thickness of the tread portion Tt, a pair of portions that face the pair of bead portions of the unvulcanized tire T via the outer bladder 4 may be treated as the second portion 57.

[0048] In the second vulcanization step S2, the pair of first parts 56 are in contact with the outer bladder 4, while the second part 57 is separated from the outer bladder 4. That is, the pair of first parts 56 are located in the contact area CR1, and the second part 57 is located in the non-contact area CR2.

[0049] In the second vulcanization step S2, the first portion 56 that contacts the outer bladder 4 and the second portion 57 that separates from the outer bladder 4 can be realized, for example, by setting the thickness of the first portion 56 during shrinkage when no internal pressure is applied to the inner bladder 5 to be smaller than the thickness of the second portion 57 during shrinkage. Alternatively, this can be achieved by adjusting the shape of the inner bladder 5 and setting the distance between the first portion 56 and the outer bladder 4 immediately after the second vulcanization step S2 to be smaller than the distance between the second portion 57 and the outer bladder 4. Furthermore, this can also be achieved by constructing the inner bladder 5 from an anisotropic composite material or the like.

[0050] With this configuration, in the second vulcanization step S2, the vulcanization speed of the pair of sidewall sections Ts, which have a smaller thickness of unvulcanized rubber, can be reduced compared to the vulcanization speed of the tread section Tt, which has a larger thickness of unvulcanized rubber. Therefore, overvulcanization of the pair of sidewall sections Ts can be suppressed, and the unvulcanized tire T can be uniformly vulcanized.

[0051] In the first vulcanization process S1 shown in Figure 4, latent heat is removed from the heating medium G1 through heat exchange with the unvulcanized tire T, and some of the steam in the heating medium G1 liquefies, forming water droplets (condensate) that adhere to the inner surface of the outer bladder 4. Such water droplets can obstruct the collision of steam gas molecules with the outer bladder 4, leading to a decrease in the efficiency of heat exchange.

[0052] However, in this embodiment, in the second vulcanization step S2, the inner bladder 5 expands, causing the heating medium G1 in the first space SP1 to be adiabatically compressed. As a result, the heating medium G1 is heated, and the condensed heating medium G1 vaporizes. In other words, the second vulcanization step S2 includes an adiabatic compression step S21 in which the heating medium G1, which has been liquefied by heat exchange with the unvulcanized tire T, is vaporized by adiabatic compression.

[0053] This adiabatic compression process S21 imparts thermal energy to the heating medium G1, compensating for the thermal energy lost in the first vulcanization process S1. Consequently, the amount of heat exchanged in the contact region CR1 during the second vulcanization process S2 is well maintained.

[0054] Figure 6 shows the stirring step S22 included in the second vulcanization step S2. It is desirable that the second vulcanization step S2 includes a stirring step S22 for stirring the heating medium G1 in the first space SP1.

[0055] In the stirring step S22, the inner bladder 5 is contracted and expanded by varying the pressure in the second space SP2. The pressure in the second space SP2 can be increased, for example, by driving a pump (not shown) located between the supply source of the pressurized medium G2 and the flow path 66. The pressure in the second space SP2 can also be decreased, for example, by operating a pressure reducing valve located between the supply source of the pressurized medium G2 and the flow path 66. With this configuration, by contracting and expanding the inner bladder 5, the heating medium G1 in the first space SP1 is stirred, reducing temperature unevenness in the heating medium G1 in the first space SP1 and improving the efficiency of heat exchange in the second vulcanization step S2.

[0056] The second vulcanization process S2 is performed until it can be determined that the vulcanization of the area facing the non-contact area CR2 via the outer bladder 4 in the unvulcanized tire T is complete.

[0057] Figure 7 is a flowchart showing the procedure of tire vulcanization method 100A, which is a modified version of tire vulcanization method 100 shown in Figure 1. For parts of tire vulcanization method 100A not described below, the configuration of tire vulcanization method 100 described above may be adopted.

[0058] Towards the end of the second vulcanization process S2, latent heat is removed from the heating medium G1 through heat exchange with the unvulcanized tire T, and some of the steam from the heating medium G1 liquefies, forming water droplets that adhere to the inner surface of the outer bladder 4. Therefore, the tire vulcanization method 100A differs from the tire vulcanization method 100 described above in that a first discharge process S3 is performed to discharge the liquefied heating medium G1.

[0059] Figure 8 shows the first discharge step S3 in the tire vulcanization method 100A. The first discharge step S3 is performed after the completion of the second vulcanization step S2. In the first discharge step S3, the liquefied heating medium G1 is discharged from the first space SP2 through the flow path 39 by maintaining the pressure in the second space SP2 at the second pressure.

[0060] When transitioning from the second vulcanization process S2 to the first discharge process S3, the pressure in the second space SP2 is maintained. In the first discharge process S3, the entire inner bladder 5 comes into contact with the outer bladder 4, and the heating medium G1 is discharged from the first space SP1. At this time, water droplets adhering to the inner surface of the outer bladder 4 in the second vulcanization process S2 are discharged from the first space SP1, and the next unvulcanized tire T is properly vulcanized in a short time. In this embodiment, the heating medium G1 and the water droplets are discharged from the first space SP1 via the flow path 39.

[0061] Furthermore, in the first discharge process S3, it is desirable that a continuous groove-shaped flow path (so-called vent line) is formed on the inner surface of the outer bladder 4 or the outer surface of the inner bladder 5, extending radially from the tread portion to the bead portion, in order to ensure the discharge of the heating medium G1 and the water droplets.

[0062] As shown in Figure 7, it is desirable that the tire vulcanization method 100A is configured such that a second discharge step S4 is performed to discharge the pressurized medium G2 after the completion of the first discharge step S3.

[0063] Figure 9 shows the second discharge step S4 in the tire vulcanization method 100A. In the second discharge step S4, the pressurized medium G2 is discharged from the second space SP2. The discharge of the pressurized medium G2 is performed, for example, by opening a valve connected to the flow path 66, etc.

[0064] In the second discharge process S4, the outer bladder 4 and inner bladder 5 contract and separate from the vulcanized tire. At this time, the vulcanized tire is released from the mold by the opening operation of the vulcanization mold 2 and becomes available for removal.

[0065] Although the tire vulcanization method 100 and other aspects of the present invention have been described in detail above, the present invention is not limited to the above-described specific embodiments and can be implemented in various modified forms.

[0066] [Note] The present invention includes the following embodiments.

[0067] [Invention 1] A method for vulcanizing a tire using a vulcanizing mold and a vulcanizing bladder placed in the cavity of an unvulcanized tire set inside the vulcanizing mold, The vulcanizing bladder includes an outer bladder that contacts the unvulcanized tire and an inner bladder disposed within the lumen of the outer bladder. The aforementioned method, A first vulcanization step in which a heating medium containing steam is supplied to at least the first space between the outer bladder and the inner bladder to expand the outer bladder and vulcanize the unvulcanized tire, The process includes a second vulcanization step in which a pressurized medium containing an inert gas is supplied to a second space within the lumen of the inner bladder, thereby expanding the inner bladder and compressing the heating medium in the first space, causing the first space to be unevenly distributed within the outer bladder, and adjusting the distribution of heat transfer to the unvulcanized tire. Tire vulcanization method. [Invention 2] The inner bladder includes, via the outer bladder, a pair of first portions facing a pair of sidewall portions of the unvulcanized tire, and a second portion facing a tread portion or a pair of bead portions of the unvulcanized tire. The tire vulcanization method according to the present invention 1, wherein in the second vulcanization step, the pair of first portions are in contact with the outer bladder, and the second portion is separated from the outer bladder. [Invention 3] The tire vulcanization method according to the present invention 1 or 2, wherein the second vulcanization step includes an adiabatic compression step of vaporizing the heating medium, which has been liquefied by heat exchange with the unvulcanized tire, by adiabatic compression. [4th Invention] The tire vulcanization method according to any one of inventions 1 to 3, wherein the second vulcanization step includes a stirring step that reduces temperature unevenness of the heating medium in the first space by varying the pressure in the second space to contract and expand the inner bladder. [5th ​​Invention] A tire vulcanization method according to any one of inventions 1 to 4, further comprising a first discharge step of discharging the heating medium after the completion of the second vulcanization step. [Invention 6] The tire vulcanization method according to claim 5 of the present invention, further comprising a second discharge step of discharging the pressurized medium after the completion of the first discharge step. [7th Invention] A tire manufacturing method for producing a tire using the tire vulcanization method described in any one of inventions 1 to 6. [Explanation of symbols]

[0068] 2: Vulcanization mold 3: Vulcanized bladder 4: Outer bladder 5: Inner bladder 56 :1st part 57:Second part 100: Tire vulcanization method 100A: Tire vulcanization method G1: Heating medium G2: Pressurized medium P2 :Second space S1: First vulcanization process S2: 2nd vulcanization process S21: Adiabatic compression process S22: Stirring process S3: 1st discharge process S4: 2nd discharge process SP1: 1st space SP2: 2nd space T: Unvulcanized tires Ts: Sidewall section Tt: Tread section

Claims

1. A method for vulcanizing a tire using a vulcanizing mold and a vulcanizing bladder placed in the cavity of an unvulcanized tire set inside the vulcanizing mold, The vulcanizing bladder includes an outer bladder that contacts the unvulcanized tire and an inner bladder disposed within the lumen of the outer bladder. The aforementioned method, A first vulcanization step in which a heating medium containing steam is supplied to at least the first space between the outer bladder and the inner bladder to expand the outer bladder and vulcanize the unvulcanized tire, The process includes a second vulcanization step in which a pressurized medium containing an inert gas is supplied to a second space within the lumen of the inner bladder, thereby expanding the inner bladder and compressing the heating medium in the first space, causing the first space to be unevenly distributed within the outer bladder, and adjusting the distribution of heat transfer to the unvulcanized tire. Tire vulcanization method.

2. The inner bladder includes, via the outer bladder, a pair of first portions facing a pair of sidewall portions of the unvulcanized tire, and a second portion facing a tread portion or a pair of bead portions of the unvulcanized tire. The tire vulcanization method according to claim 1, wherein in the second vulcanization step, the pair of first portions are in contact with the outer bladder and the second portion is separated from the outer bladder.

3. The tire vulcanization method according to claim 1, wherein the second vulcanization step includes an adiabatic compression step of vaporizing the heating medium, which has been liquefied by heat exchange with the unvulcanized tire, by adiabatic compression.

4. The tire vulcanization method according to claim 1, wherein the second vulcanization step includes a stirring step of reducing temperature unevenness of the heating medium in the first space by causing the inner bladder to contract and expand by varying the pressure in the second space.

5. The tire vulcanization method according to claim 1, further comprising a first discharge step of discharging the heating medium after the completion of the second vulcanization step.

6. The tire vulcanization method according to claim 5, further comprising a second discharge step of discharging the pressurized medium after the completion of the first discharge step.

7. A tire manufacturing method for manufacturing a tire using the tire vulcanization method described in any one of claims 1 to 6.

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