JP7518360B2 - TIRE MANUFACTURING METHOD AND TIRE VULCANIZING APPARATUS - Google Patents

Description

The present invention relates to a tire manufacturing method and a tire vulcanization device, and more specifically, to a tire manufacturing method and a tire vulcanization device that can quickly deal with the peeling of the marking plate that occurs during tire vulcanization, thereby improving tire productivity.

Generally, the sidewall of a pneumatic tire is engraved with identification information that indicates the date and place of manufacture of the tire using symbols and numbers. Because such identification information needs to be changed over time, the identification information is not engraved directly onto the tire molding surface of the mold, but rather the necessary information is engraved on a metal engraved plate, which is then replaceably attached to the tire molding surface of the mold (see, for example, Patent Documents 1 and 2).

However, the marking plate attached to the mold may peel off from the mold during tire production. In this case, tires without identification information engraved on the sidewall will be manufactured until the peeling of the marking plate is addressed. Such tires will have to be discarded, resulting in a problem of reduced tire productivity.

Japanese Patent Application Publication No. 60-64809 Japanese Utility Model Application Publication No. 4-126838

The object of the present invention is to provide a tire manufacturing method and tire vulcanization device that can quickly deal with the peeling of the marking plate that occurs during tire vulcanization, thereby improving tire productivity.

To achieve the above-mentioned object, the tire manufacturing method of the present invention is characterized in that after vulcanizing an unvulcanized tire in a mold of a vulcanizing device, metal pieces attached to the outer surface of the vulcanized tire are detected by a metal detection means, the metal detection means scans the sidewall portion of the vulcanized tire, and when a metal piece attached to the outer surface of the vulcanized tire is detected, the operation of the vulcanizing device is stopped .

In addition, the tire vulcanizing apparatus of the present invention is a vulcanizing apparatus equipped with a mold for vulcanizing unvulcanized tires, and is equipped with a metal detection means for detecting metal pieces attached to the outer surface of the vulcanized tire, and has a control unit for controlling the operation of the vulcanizing apparatus, characterized in that when the metal detection means detects metal pieces attached to the outer surface of the vulcanized tire by scanning the sidewall portion of the vulcanized tire, the control unit stops the operation of the vulcanizing apparatus .

In the present invention, after vulcanizing an unvulcanized tire in the mold of a vulcanizing device, metal pieces adhering to the outer surface of the vulcanized tire are detected by a metal detection means, so that peeling of the marking plate can be dealt with during the vulcanization process (particularly immediately after vulcanization and before the inspection process), which is useful for preventing the production of tires without engraved identification information. In this way, peeling of the marking plate that occurs during vulcanization molding can be dealt with quickly, thereby improving tire productivity.

It is preferable to stop the operation of the vulcanizing device when metal pieces adhering to the outer surface of a vulcanized tire are detected. This allows for prompt action to be taken in the event that the marking plate peels off during the vulcanization of the tire.

When metal pieces are detected adhering to the outer surface of a vulcanized tire, it is preferable to stop the operation of the vulcanizer before the next unvulcanized tire is inserted into the mold of the vulcanizer. This allows for prompt action to be taken against any peeling of the marking plate that occurs during vulcanization of the tire.

The metal detection means preferably scans the sidewall portion of the vulcanized tire. For example, if a metal detector is used as the metal detection means, scanning the bead portion, which has metal components, will result in erroneous detection of necessary tire components. Therefore, by limiting the scanning area of the metal detection means to the sidewall portion, peeling of the marking plate can be accurately detected.

FIG. 1 is an explanatory diagram showing an example of a tire vulcanizing device according to an embodiment of the present invention. 2A to 2C are explanatory diagrams showing the operation of the vulcanizing apparatus of FIG. 1 over time, where (a) shows the state before the vulcanizing process, (b) shows the state after the vulcanizing process in the process of transporting the vulcanized tire to the PCI apparatus, and (c) shows the state immediately before the start of the PCI process. FIG. 1 is a side view showing an example of a vulcanized tire with metal pieces attached thereto. FIG. 11 is a plan view of a modified tire vulcanizing device according to an embodiment of the present invention, showing a state in which a vulcanized tire is being transported on metal rollers.

The tire vulcanization device according to an embodiment of the present invention will be described in detail below with reference to the attached drawings. FIG. 1 shows a tire vulcanization device according to an embodiment of the present invention. Note that FIG. 1 shows a state in which a vulcanized tire T is held in a mold 10 after the vulcanization process is completed.

As shown in FIG. 1, the tire vulcanizing device of the present invention (hereinafter referred to as vulcanizing device 1) comprises a base 1a supporting a bladder 30 and a central mechanism 40, a casing 20 suspended above the base 1a, a mold 10 provided inside the casing 20 for forming the outer surface of an unvulcanized tire, a metal detection means 2 for detecting a metal piece 3 (engraved plate) attached to the outer surface of a vulcanized tire T, and a control unit for controlling the operation of the vulcanizing device 1. The base 1a is configured to be movable horizontally.

The bladder 30 provided on the base 1a is a tubular member made of rubber that is inserted into the inside of the unvulcanized tire during vulcanization and presses the unvulcanized tire from the inside toward the mold 10. Center posts 41 that constitute the central mechanism 40 are inserted vertically through the bladder 30. The upper and lower edges of the bladder 30 are each held by the central mechanism 40.

The central mechanism 40 is used to control the expansion and contraction of the bladder 30. The center post 41 that constitutes the central mechanism 40 is provided with an injection tube that injects steam, which serves as a heating medium, and an inert gas (such as nitrogen gas), which serves as a pressurizing medium, into the inside of the bladder 30, and an exhaust tube that exhausts each medium inside the bladder 30 to the outside of the bladder 30.

The casing 20 includes an upper plate 21 attached to a lifting means (not shown), a lower plate 22 fixed on the base 1a, segments 23 arranged on the outer peripheral surface of the sector 11 described below, and a ring 24 that expands and contracts the sector 11 together with the segments 23 as the upper plate 21 rises and falls. The casing 20 is configured to be able to rise and fall vertically together with the mold 10.

The mold 10 is a sectional type mold including sectors 11 divided into a plurality of sectors in the circumferential direction for forming the tread portion of the unvulcanized tire, and an upper mold 12 and a lower mold 13 for forming the sidewall portion of the unvulcanized tire. The upper mold 12 is fixed to the lower surface of the upper plate 21, and the lower mold 13 is fixed to the upper surface of the lower plate 22. The sectors 11, upper mold 12, and lower mold 13 are all annular. The mold 10 is designed to vulcanize and mold the unvulcanized tire loaded into its cavity with its rotation axis oriented vertically.

A metal stamping plate (metal piece 3) showing the tire's identification information in the form of symbols and numbers is replaceably attached to the tire molding surface of the mold 10 with adhesive or the like. The tire's identification information includes the date and place of manufacture. The mounting position of the stamping plate is not particularly limited and it can be attached to any position on the tire molding surface of the mold 10, but it is generally attached to an area corresponding to the sidewall portion on one side of the tire. In this embodiment, the stamping plate is attached to the lower mold 13.

When the metal detection means 2 detects a metal piece 3 attached to the outer surface of the vulcanized tire T, it is configured to feed back the detection result to the control unit of the vulcanization device 1. Examples of this metal detection means 2 include a detection device including a camera, an optical sensor, or a metal detector. For example, in the case of a camera, an image processing device can detect the metal piece 3 based on an image taken by the camera, and in the case of an optical sensor, the metal piece 3 can be detected by irradiating light onto the vulcanized tire T with a light irradiation device and detecting the reflected light from the metal piece 3 with an optical sensor. In addition, since metal members are generally used in the bead portion and belt layer that constitute a pneumatic tire, the metal detector can detect the metal piece 3 by being positioned relative to the vulcanization device 1 so that it can scan the sidewall portion of the vulcanized tire T.

In addition, in FIG. 1, the position of the metal detection means 2 is not limited to the position shown in the figure, and can be changed as appropriate as long as it is a position where the metal piece 3 can be detected after the vulcanization process is completed and before the inspection process is reached.

The control unit of the vulcanizing device 1 is configured to stop the operation of the vulcanizing device 1 when the metal detection means 2 detects the metal piece 3. More specifically, the control unit of the vulcanizing device 1 is configured to stop the operation of the vulcanizing device 1 when the metal detection means 2 detects the metal piece 3 before the next unvulcanized tire is inserted into the mold 10.

A PCI device 50 (post-cure inflation device) is installed adjacent to the vulcanizing device 1. This PCI device 50 cools the vulcanized tire T while suppressing the shrinkage of the reinforcing cords in the tire and stabilizing the shape of the tire.

When vulcanizing an unvulcanized tire using the vulcanizing device 1 described above, as shown in FIG. 2(a), the mold 10 is opened, an unvulcanized tire G is set on the central mechanism 40, and the base 1a moves to the rear side (left side in the figure) of the vulcanizing device 1 and moves horizontally until the central axis of the casing 20 and the central axis of the central mechanism 40 are in the same position. Then, the casing 20 is lowered via the lifting means (not shown) and moves downward until it abuts against the lower plate 22. As a result, each sector 11 constituting the mold 10 moves toward the central mechanism 40 and is assembled in a ring shape, and the mold 10 is closed and clamped. With the mold 10 closed and clamped, a heating medium such as steam and a pressurizing medium are injected inside the bladder 30, and the mold 10 is heated from the outside by the heating means to vulcanize the unvulcanized tire G.

During this vulcanization process, if the metal piece 3 (engraving plate) attached to the tire molding surface of the mold 10 peels off due to a decrease in adhesive strength, etc., the metal piece 3 will remain attached to the outer surface (sidewall portion Ts) of the vulcanized tire T, as shown in Figure 3.

After the above-mentioned vulcanization process is completed, the bladder 30 is pulled out from inside the vulcanized tire T by the operation of the central mechanism 40, and the casing 20 is raised via the lifting means and moves upward until it reaches a predetermined position. When the casing 20 reaches the predetermined position, it is in the state shown in FIG. 1. Then, the pedestal 1a moves to the front side (right side in the figure) of the vulcanization device 1. In the process of the pedestal 1a moving to the front side of the vulcanization device 1, as shown in FIG. 2(b), the vulcanized tire T passes directly above the metal detection means 2, so that the metal detection means 2 can scan the outer surface (sidewall portion Ts) of the vulcanized tire T to detect the metal piece 3. Then, as shown in FIG. 2(c), the pedestal 1a moves horizontally until the central axis of the casing 20 and the central axis of the PCI device 50 are in the same position. After that, the casing 20 moves downward, the vulcanized tire T is set in the PCI device 50, and the PCI process begins. In this way, after the vulcanization process is completed, the metal pieces 3 can be detected using the metal detection means 2, and the tire can be manufactured.

Even if the metal piece 3 is located on the opposite side to the illustrated position (located in front of the vulcanizing device 1), the vulcanized tire T passes above the metal detection means 2 during the process of being transported to the PCI device 50, so the metal detection means 2 can scan the outer surface of the vulcanized tire T to detect the metal piece 3.

Furthermore, if the metal detection means 2 detects a metal piece 3, the metal detection means 2 feeds back the detection result to the control unit of the vulcanizer 1, and the control unit of the vulcanizer 1 stops the operation of the vulcanizer 1. More specifically, the timing at which the control unit stops the operation of the vulcanizer 1 is before the next unvulcanized tire is inserted into the mold 10 of the vulcanizer 1. After stopping the vulcanizer 1 in this way, a new marking plate is attached to a specified position on the tire molding surface of the mold 10, and the vulcanization process is resumed.

In the vulcanizing device 1 described above, after vulcanizing an unvulcanized tire in the mold 10, the metal detection means 2 detects metal pieces 3 attached to the outer surface of the vulcanized tire T, making it possible to deal with peeling of the marking plate during the vulcanization process (particularly immediately after vulcanization and before the inspection process), which is useful for preventing the production of tires without engraved identification information. In this way, peeling of the marking plate that occurs during vulcanization molding can be dealt with quickly, thereby improving tire productivity.

In the above vulcanizing device 1, when the metal detection means 2 detects a metal piece 3 attached to the outer surface of the vulcanized tire T, the control unit of the vulcanizing device 1 preferably stops the operation of the vulcanizing device 1, and more preferably stops the operation of the vulcanizing device 1 before the next unvulcanized tire is inserted into the mold 10 of the vulcanizing device 1. By stopping the operation of the vulcanizing device 1 in this way, it is possible to quickly deal with the peeling of the marking plate that occurs during vulcanization of the tire.

In addition, it is preferable that the metal detection means 2 scan the sidewall portion Ts of the vulcanized tire T. For example, if a metal detector is used as the metal detection means 2, scanning the bead portion Tb, which has a metal member, will result in erroneous detection of necessary tire components (such as the bead portion and belt layer made of a metal member). Therefore, by limiting the scanning area of the metal detection means 2 to the sidewall portion Ts, peeling of the marking plate can be accurately detected.

Figure 4 shows a modified example of a tire vulcanization device according to an embodiment of the present invention, in which a vulcanized tire T is being transported on a metal roller. While Figure 1 and Figures 2(a) to (c) show an example in which the process moves to the PCI process after the vulcanization process is completed, Figure 4 shows an example of the arrangement of the metal detection means 2 when the process moves to the inspection process without going through the PCI process after the vulcanization process is completed.

As shown in FIG. 4, the conveying means 100 for conveying the vulcanized tire T includes multiple metal rollers 110 that are configured to rotate freely. These metal rollers 110 are free rollers that do not have a driving unit, and are arranged in parallel at a predetermined interval from each other in a direction perpendicular to the conveying direction R of the vulcanized tire T. The vulcanized tire T is conveyed in the conveying direction R by the rotation of each metal roller 110.

The metal detection means 2 is installed between adjacent metal rollers 110. The metal detection means 2 is installed so as to be able to scan the side surface (sidewall portion Ts) on which the identification information of the vulcanized tire T is engraved. In this embodiment, the metal detection means 2 is installed on the lower side of the vulcanized tire T so as to scan the sidewall portion Ts that abuts against the metal roller 110. Note that the side surface on which the identification information of the vulcanized tire T is engraved can be changed as appropriate, and therefore the position at which the metal detection means 2 is installed relative to the conveying means 100 can also be changed accordingly.

By installing the metal detection means 2 on the conveying means 100 in this manner, the metal detection means 2 can scan the outer surface (sidewall portion Ts) of the vulcanized tire T during the process of conveying the vulcanized tire T. If the metal detection means 2 detects a metal piece 3, the metal detection means 2 feeds back the detection result to the control unit of the vulcanizer 1, and the control unit of the vulcanizer 1 stops the operation of the vulcanizer 1 before the next unvulcanized tire is inserted into the mold 10. This allows for quick response to peeling of the marking plate that occurs during vulcanization molding, thereby improving tire productivity.

In the above explanation, a sectional type mold 10 was used, but the structure of the mold 10 is not particularly limited, and a mold with two upper and lower parts can also be used.

30,000 tires were manufactured using the vulcanizing device of the embodiment, which is equipped with a mold for vulcanizing unvulcanized tires and a metal detection means for detecting metal pieces attached to the outer surface of a vulcanized tire. The tire size of the manufactured tires is 195/65R15.

For comparison, 30,000 tires were manufactured using a conventional vulcanizing device that has the same structure as the vulcanizing device of the embodiment, except that it does not have a metal detection means for detecting metal pieces attached to the outer surface of the vulcanized tire.

In the inspection process, tires manufactured using each vulcanizing device were inspected to see if the identification information was correctly stamped on the sidewall, and the number of tires that were not correctly stamped was counted. As a result, there were 10 tires that fell into this category when the conventional vulcanizing device was used, whereas there were zero tires that fell into this category when the vulcanizing device of the embodiment was used.

The vulcanizing device of the embodiment did not produce tires with the identification information not properly stamped on the sidewall, confirming that it has an improving effect on tire productivity. In other words, even if the marking plate peels off during the vulcanizing process, the vulcanizing device of the embodiment can quickly deal with the problem, and can prevent the production of tires without the identification information stamped on them.

Reference Signs List 1 Vulcanization device 2 Metal detection means 3 Metal piece 10 Mold T Vulcanized tire

Claims (4)

A tire manufacturing method comprising the steps of: vulcanizing an unvulcanized tire in a mold of a vulcanizing device; detecting metal pieces adhering to the outer surface of the vulcanized tire using a metal detection means; scanning a sidewall portion of the vulcanized tire; and stopping operation of the vulcanizing device when the metal detection means detects metal pieces adhering to the outer surface of the vulcanized tire . The tire manufacturing method described in claim 1, characterized in that when a metal piece attached to the outer surface of the vulcanized tire is detected, the operation of the vulcanizer is stopped before the next unvulcanized tire is inserted into the mold of the vulcanizer. A tire vulcanizing apparatus having a mold for vulcanizing unvulcanized tires, comprising a metal detection means for detecting metal pieces attached to the outer surface of a vulcanized tire , and a control unit for controlling the operation of the vulcanizing apparatus, wherein the control unit stops the operation of the vulcanizing apparatus when the metal detection means detects metal pieces attached to the outer surface of the vulcanized tire by scanning the sidewall portion of the vulcanized tire. A tire vulcanizing apparatus as described in claim 3, characterized in that when the metal detection means detects a metal piece attached to the outer surface of the vulcanized tire, the control unit stops the operation of the vulcanizing apparatus before the next unvulcanized tire is inserted into the mold of the vulcanizing apparatus.

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