JP7614486B2 - How to clean tire curing bladders - Google Patents

Description

The present invention relates to a method for cleaning a tire vulcanization bladder, and more specifically, to a method for cleaning a tire vulcanization bladder that removes dirt or unnecessary irregularities on the outer surface without wasting a tire vulcanization bladder with a sound base material, allowing it to be used repeatedly.

When vulcanizing a green tire, a tire vulcanization bladder is expanded inside the green tire placed in the tire vulcanization mold, and the green tire is heated while being pressurized. A release agent is often applied to the outer surface of the vulcanization bladder to prevent adhesion with the inner surface of the vulcanized tire (see, for example, Patent Document 1). Some tire vulcanization bladders have an outer surface that is not covered with a release agent layer. Unwanted dirt adheres to the outer surface of these tire vulcanization bladders as they are repeatedly vulcanized, and as the dirt increases, it affects the appearance quality of the vulcanized tire. For this reason, tire vulcanization bladders are replaced with new ones after, for example, a specified period or a specified number of uses. In addition, if the outer surface of the tire vulcanization bladder becomes rough (unwanted unevenness occurs) due to repeated use, it is also replaced with a new one.

Tire vulcanization bladders that are replaced with new ones often only have dirty outer surfaces or unnecessary irregularities, but the bladder itself (the bladder base) still has sufficient durability. Therefore, there is room for improvement in order to reuse vulcanization bladders with a healthy base without wasting them.

JP 2009-83466 A

The object of the present invention is to provide a method for cleaning tire vulcanization bladders that removes dirt or unnecessary irregularities on the outer surface without wasting a tire vulcanization bladder with a sound base material, allowing it to be reused repeatedly.

In order to achieve the above object, the cleaning method for a tire vulcanization bladder of the present invention is a cleaning method for removing dirt attached to the outer surface of a tire vulcanization bladder by vulcanizing a green tire, the dirt being a component of a rubber composition forming the green tire, and the dirt is removed together with the surface layer of the outer surface by scraping the bladder from the outer periphery, and the surface remaining after the surface layer is removed is exposed as a new surface layer.

Another method for cleaning a tire vulcanization bladder of the present invention is a cleaning method for removing unnecessary irregularities that roughen the base surface by vulcanizing a green tire using a tire vulcanization bladder that has a specification in which the base surface is exposed as it is, and is characterized in that by scraping the bladder from the outer periphery, a thin layer of the base surface is removed as a surface layer on the outer surface of the bladder, and a new surface of the base surface is exposed that is free of adhesion of components of the rubber composition that forms the green tire and from which the irregularities have been removed .

According to the former cleaning method, when the bladder is scraped from the outer periphery, the outer surface of the bladder can be removed together with the surface layer of the bladder and dirt adhering to the outer surface. After the surface layer is removed, the surface is exposed as a new surface layer, and this new surface layer is free of dirt and in a brand new condition. This makes it possible to repeatedly use the bladder without wasting a healthy base material.

According to the latter cleaning method, when the bladder is scraped from the outer periphery, a thin layer of the base surface of the bladder is removed as the outer surface layer of the bladder, thereby removing unnecessary irregularities on the outer surface. After removing the surface layer, a new surface of the base surface is exposed as a new surface layer, and this new surface layer is free of unnecessary irregularities. Therefore, it becomes possible to repeatedly use the bladder without wasting a bladder with a healthy base material.

FIG. 2 is an explanatory diagram illustrating a tire vulcanization bladder as viewed from the front. FIG. 2 is an explanatory diagram illustrating the tire vulcanization bladder of FIG. 1 in a plan view. FIG. 3 is an explanatory diagram illustrating the left half of the tire vulcanization bladder of FIG. 2 in a vertical cross-sectional view. FIG. 4 is a partially enlarged view of FIG. 3 . 1 is an explanatory diagram illustrating a tire vulcanization bladder cleaning device as viewed from the front with the right half of the vulcanization bladder in vertical section; FIG. 6 is an explanatory diagram illustrating the cleaning device of FIG. 5 in a plan view. FIG. 5 is an explanatory diagram illustrating a state in which the dirt in FIG. 4 has been removed. FIG. 11 is an explanatory diagram illustrating the left half of a tire vulcanization bladder of another specification in a vertical cross-sectional view. FIG. 9 is a partially enlarged view of FIG. 8 . FIG. 10 is an explanatory diagram illustrating a state in which the dirt in FIG. 9 has been removed.

The method for cleaning a tire vulcanization bladder of the present invention will be described below based on the embodiment shown in the figure.

The tire vulcanization bladder 10 (hereinafter referred to as the bladder 10) illustrated in Figures 1 to 4 is a cylindrical body with both ends open. The dashed line CL in the figure indicates the position of the cylindrical axis of the bladder 10. The base material of the bladder 10 is formed of vulcanized rubber, so the base material surface 11 is vulcanized rubber. The present invention can be applied to bladder 10 in both cases, whether the bladder 10 has a release agent layer 12 on its outer surface 13 as illustrated in Figures 3 and 4, or the bladder 10 does not have a release agent layer 12 on its outer surface 13 as illustrated in Figures 8 and 9, and the bladder 10 has a base material surface 11 exposed as its outer surface 13.

On the outside of the bladder 10 of the specifications illustrated in Figures 3 and 4, the substrate surface 11 is coated with a release agent layer 12. The inner surface 14 of the bladder 10 is not coated with the release agent layer 12, so the substrate surface 11 is exposed.

The release agent that forms the release agent layer 12 has the function of preventing adhesion between the base surface 11 of the bladder 10 and the vulcanized tire, and allowing the tire to be smoothly peeled off from the bladder 10. The release agent layer 12 is formed from a known release agent such as a fluororesin or silicone. The thickness of the release agent layer 12 varies depending on the size of the tire to be vulcanized, but is generally about 10 μm to 200 μm, for example.

In this embodiment, the thickness of the release agent layer 12 is equal to or greater than the general thickness, for example, 100 μm or more. The upper limit of the thickness of the release agent layer 12 is, for example, 500 μm.

The outside of the bladder 10 in the specifications illustrated in Figures 8 and 9 is not covered with a release agent layer 12, and the substrate surface 11 is exposed as is. The inner surface 14 of the bladder 10 is also not covered with a release agent layer 12, and the substrate surface 11 is exposed as is.

When the bladder 10 is repeatedly used to manufacture tires by vulcanizing green tires, dirt X gradually adheres to the outer surface 13 and the amount of dirt X adheres to the outer surface 13 increases. The dirt X is a rubber composition (a component of the rubber composition) that forms the green tire. As the amount of dirt X adheres to the tire increases, the bladder 10 adheres more strongly to the vulcanized tire, making it difficult to peel the bladder 10 from the tire. In addition, unevenness caused by the dirt X is formed on the inner surface of the vulcanized tire. In the figure, the shaded area indicates the dirt X, and the release agent layer 12 and the dirt X are drawn to be exaggeratedly thick.

In the present invention, for example, after the bladder 10 has been used for a specified period or a specified number of times, the bladder 10 is scraped from the outer periphery to remove the surface layer 13a of the outer surface 13 and the dirt X adhering to the outer surface 13. Then, the surface after removing the surface layer 13a is exposed as a new surface layer 13b.

First, an example of the procedure for cleaning the bladder 10 with the specifications shown in Figures 3 and 4 will be described below.

The inventors of the present application analyzed a number of bladders 10 with dirt X attached and found that, under the same conditions of use, the amount (accumulation) of dirt X increases with the number of times it is used, but the release agent layer 12 does not wear out significantly and its thickness remains almost the same. In addition, they found that, under the same conditions of use, the degree of accumulation of dirt X is substantially the same even if the thickness of the release agent layer 12 is different.

Therefore, in this specification of the bladder 10, when the bladder 10 is scraped from the outer periphery, a thin layer of the release agent layer 12 is removed as the surface layer 13a, and a new surface of the release agent layer 12 is exposed as a new surface layer 13b. In other words, the release agent layer 12 remains after cleaning. In the figure, the dirt X is scattered (dotted), but the degree of adhesion of the dirt X varies, and it may adhere in a thin film over a wide area.

As illustrated in Figures 5 and 6, the cleaning device 1 used in this embodiment includes a freely movable arm 3, a processing head 2 held at the tip of the arm 3, a nozzle 2a installed on the processing head 2, a processing medium supply source 7 connected to the processing head 2 via a pipe or cable, a booth 5, and a control unit 8 that controls the movement of the arm 3 and the supply amount of processing medium M from the processing medium supply source 7. It also includes a distance sensor 6 that detects the distance from the tip of the nozzle 2a to the opposing surface (outer surface 13). The rear end of the arm 3 is rotatably connected to a base 4.

When sand is used as the processing medium M and sandblast cleaning is performed, sand is stored in the processing medium supply source 7 and pressure-fed to the processing head 2 (nozzle 2a) via a pipe. When plasma is used as the processing medium M and plasma cleaning is performed, gas for generating plasma is stored in the processing medium supply source 7 and pressure-fed to the processing head 2 (nozzle 2a) via a pipe. When laser light is used as the processing medium M and laser light cleaning is performed, the processing medium supply source 7 is a laser light oscillator, and the laser light is sent to the processing head 2 (nozzle 2a) via an optical fiber cable.

The bladder 10 is installed inside the booth 5, and the inner surface 14 is covered with a protective material 9 that blocks the treatment medium M. It is recommended to close both end openings of the bladder 10 and apply internal pressure to slightly expand the bladder 10 before cleaning.

The processing head 2 and nozzle 2a are moved to a desired position inside the booth 5, and the processing medium M is supplied (sprayed or irradiated) from the outer periphery of the bladder 10 so as to cover the entire range of the outer surface 13. The processing medium M is not limited to being supplied while the bladder 10 is kept stationary, but can also be supplied while the bladder 10 is rotated around its cylindrical axis CL.

The arm 3 can be controlled to move along the outer surface 13 based on the external shape data of the bladder 10, or can be moved manually. In this embodiment, the inner surface 14 of the bladder 10 is covered with a protective material 9, so that the processing medium M being supplied is blocked and protected from the processing medium M.

By supplying (spraying, irradiating) the treatment medium M from the outer periphery to the outer surface 13 for an appropriate cleaning time, a thin layer of the release agent layer 12 is removed as the surface layer 13a, as shown in FIG. 7. The type of cleaning is not limited to sandblast cleaning, plasma cleaning, and laser light cleaning. For example, an abrasive such as a brush or file can be attached to the tip of the arm 3 to remove the surface layer 13a. The thickness of the surface layer 13a to be removed varies depending on the type of cleaning, but is, for example, about 20μ to 50μm.

This removes the dirt X adhering to the outer surface 13 together with the surface layer 13a. As a result, the surface of the release agent layer 12 after the surface layer 13a has been removed is exposed as a new surface layer 13b, completing the cleaning process. The protective material 9 is removed from the inner surface 14.

The release agent layer 12 remains on the outer surface 13 of the bladder 10 after cleaning. In other words, the outer surface 13 is formed of the release agent layer 12, ensuring releasability. The cleaned bladder 10 can be used again to vulcanize green tires, just like when it was new, by utilizing the existing release agent layer 12. This allows the bladder 10, whose base material is still sound, to be used repeatedly without being wasted.

As mentioned above, it is preferable to make the initial thickness of the release agent layer 12 larger than the general thickness, or 50 μm or more, and more preferably 80 μm or more, since this widens the range of appropriate cleaning times. This also makes it possible to increase the number of times the bladder 10 can be cleaned and reused. As mentioned above, even if the release agent layer 12 is made thicker, the amount of dirt X that adheres to it does not increase.

The thickness of the dirt X to be removed when the bladder 10 is scraped from the outer periphery is determined, for example, before cleaning is started. Specifically, the relationship between the use time of the bladder 10 and the amount of dirt X deposited on the outer surface 13 is grasped in advance. Then, at the time of cleaning the bladder 10, the amount of dirt X deposited (deposition thickness) is predicted, and the thickness of the dirt X from the surface of the dirt X to a predetermined depth position exceeding the deposition thickness is determined as the thickness of the dirt X to be removed from the surface layer 13a. The amount of dirt X deposited (volume thickness) can also be predicted based on the detection rate of the dirt X components by XRF analysis (X-ray fluorescence analysis) of the outer surface 13. Then, for example, while detecting the scraping thickness by the distance sensor 6, cleaning is performed until the determined scraping thickness is reached, and the surface layer 13a is removed.

The thickness to be removed when scraping the bladder 10 from the outer periphery can also be determined based on the state of dirt X remaining on the outer surface 13 ascertained while removing the surface layer 13a. Whether dirt X remains on the outer surface 13 can be determined based on various indicators. Examples of such indicators include the color of the outer surface 13, the unevenness (surface roughness), differences in adhesive strength, and the results of XRF analysis (X-ray fluorescence analysis) of the outer surface 13.

Therefore, a target value for the indicator to be used when dirt X is substantially not present is set. Then, cleaning is performed while detecting at least one of the indicators, and cleaning is continued until the detected indicator reaches the target value, thereby removing the surface layer 13a.

The procedure for cleaning the bladder 10 with the specifications illustrated in Figures 8 and 9 is generally the same as for the bladder 10 with the specifications illustrated in Figures 3 and 4, so we will only explain the differences.

In a bladder 10 that does not have a release agent layer 12 on the outer surface 13, when the bladder 10 is scraped from the outer periphery, the treatment medium M is supplied (sprayed, irradiated) from the outer periphery to the outer surface 13 for an appropriate cleaning time, thereby removing a thin layer of the base surface 11 as the surface layer 13a, as shown in FIG. 10. This removes the dirt X adhering to the outer surface 13 together with the surface layer 13a. Accordingly, the surface of the base surface 11 after the surface layer 13a has been removed is exposed as a new surface layer 13b, completing the cleaning process.

The cleaned bladder 10 can be used again to vulcanize green tires, just as if it were new. This allows the bladder 10, whose base material is still sound, to be used repeatedly without being wasted.

By repeatedly using the bladder 10 shown in Figures 8 and 9, even if there is no dirt X, the outer surface 13 becomes rough, that is, unwanted irregularities are generated. If a tire is vulcanized using a bladder 10 with excessive irregularities, the inner surface of the vulcanized tire becomes rough due to the formation of irregularities caused by the unwanted irregularities.

Therefore, cleaning can be performed to remove unnecessary irregularities formed on the outer surface 13. The cleaning procedure is the same as in the previous embodiment. That is, by scraping the bladder 10 from the outer periphery using the processing medium M, a thin layer of the base surface 11 of the bladder 10 is removed as the surface layer 13a of the outer surface 13 of the bladder 10. This exposes a new surface of the base surface 11 as a new surface layer 13b.

By removing the thin layer of the base surface 11, it is possible to remove unnecessary irregularities that have formed on the outer surface 13. Therefore, the cleaned bladder 10 can be used again to vulcanize green tires, just as if it were new. This allows the bladder 10, whose base is still sound, to be used repeatedly without being wasted.

Reference Signs List 1 Cleaning device 2 Treatment head 2a Nozzle 3 Arm 4 Base 5 Booth 6 Distance sensor 7 Treatment medium supply source 8 Control unit 9 Protective sheet 10 Tire vulcanization bladder 11 Base surface 12 Release agent layer 13 Outer surface 13a Surface layer 13b New surface layer 14 Inner surface M Treatment medium X Dirt

Claims (6)

A cleaning method for removing dirt adhering to an outer surface of a tire vulcanization bladder by vulcanizing a green tire , the dirt being a component of a rubber composition forming the green tire,
A method for cleaning a tire vulcanization bladder, comprising the steps of: scraping the bladder from the outer periphery to remove the dirt together with the surface layer of the outer surface , and exposing the surface remaining after the surface layer has been removed as a new surface layer. The method for cleaning a tire vulcanization bladder according to claim 1, wherein the outer surface has a release agent layer, and a thin layer of the release agent layer is removed as the surface layer to expose a new surface of the release agent layer as the new surface layer. The method for cleaning a tire vulcanization bladder according to claim 1, wherein the outer surface is formed by the base surface of the bladder, and a thin layer of the base surface is removed as the surface layer to expose a new surface of the base surface as the new surface layer. A method for cleaning a tire vulcanization bladder according to any one of claims 1 to 3, in which the thickness to be scraped when scraping the bladder from the outer periphery is determined before starting cleaning. A method for cleaning a tire vulcanization bladder according to any one of claims 1 to 3, in which the thickness of the bladder to be scraped from the outer periphery is determined based on the remaining state of the dirt ascertained while removing the surface layer. A cleaning method for removing unnecessary irregularities that cause a rough surface of a green tire to become rough by vulcanizing the green tire using a tire vulcanization bladder that has a specification in which the surface of the base material is exposed as it is , comprising the steps of:
A method for cleaning a tire vulcanization bladder, comprising the steps of: scraping the bladder from the outer periphery; removing a thin layer of the base surface as a surface layer of the outer surface of the bladder; and exposing a new surface of the base surface that is free of adhesion of components of the rubber composition forming the green tire and from which the irregularities have been removed.

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