Tire vulcanizing equipment

Abstract

To provide tire vulcanizing equipment that does not require changing the clamp when the inside diameter of a pneumatic tire to be formed is changed.SOLUTION: The tire vulcanizer 10 is provided with a mold 11 having a molding surface for molding a tire surface, a bladder 51 expandable toward the molding surface of the mold 11, and clamps 55 and 56 holding the upper and lower sides of the bladder 51 respectively on the inner side of the mold 11 in the radial direction. The mold 11 has a bead ring 16 that runs around the circumferential direction of the mold as a member of the radial direction inner edge of each of the upper and lower parts, the bladder 51 has opening edges 58 and 59 that run around the circumferential direction of the mold on the radial direction inner side of the mold 11, and the clamps 55 and 56 holding the opening edges 58, 59 of the bladder 51 respectively on the upper and lower parts, respectively, over one circumferential direction of the mold. Spacers 20 and 30 are sandwiched between bead ring 16 and clamps 55 and 56 in the circumferential direction of the mold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire vulcanizing apparatus. [Background technology]

[0002] As shown in Patent Document 1, a tire vulcanization apparatus for vulcanizing and molding pneumatic tires includes a mold that contacts the outer surface of the tire to mold the tread and other components, and a bladder that expands inside the mold and is pressed against the inner surface of the tire. The mold is composed of sectors that mold the tread, side plates that mold the sidewalls, and a bead ring that molds the bead portions. Furthermore, on the radially inner side of the mold, two clamps, one above the other, hold the upper and lower opening edges of the bladder, respectively. The clamps contact the inner peripheral surface of the bead ring of the mold. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-6214 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vulcanization molding process using a tire vulcanizer like the one described above, when molding a pneumatic tire with a different inner diameter than the previous one begins, not only the mold but also the bladder and the clamp that holds it are replaced. This is because the outer diameter of the clamp must also change to match the change in tire inner diameter, and because the bladder is usually prepared while held in the clamp. However, replacing the clamp is a time-consuming process. Another problem is that it is necessary to produce and manage a large number of clamps that fit the inner diameter of the pneumatic tire to be molded.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a tire vulcanizing apparatus that does not require changing clamps when the inner diameter of a pneumatic tire to be molded is changed. [Means for solving the problem]

[0006] A tire vulcanizing apparatus according to an embodiment is provided with a mold having a molding surface for molding the tire surface, a bladder that can expand toward the molding surface of the mold, and two clamps that hold the top and bottom of the bladder on the radially inner side of the mold, and bead rings that run around the mold circumferentially as components at the radially inner ends of the mold, and the bladders have opening edges that run around the mold circumferentially on both the top and bottom, and the clamps hold the opening edges of the bladders around the mold circumferentially on both the top and bottom, and in this tire vulcanizing apparatus, a spacer that runs around the mold circumferentially is sandwiched between the bead rings and the clamps. The clamp includes an upper holding member and a lower holding member that sandwich the opening edge of the bladder from above and below, and the spacer is not fixed to the clamp. It is characterized by: [Effects of the Invention]

[0007] In the tire vulcanizing apparatus of the embodiment, when the inner diameter of the pneumatic tire to be molded is changed, the spacers can be replaced with ones having a different outer diameter, so there is no need to change the clamps. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. [Figure 2] FIG. 4 is an exploded cross-sectional view showing the upper side plate, bead ring, spacer, and clamp. [Figure 3] FIG. 10 is an exploded cross-sectional view showing the lower side plate, bead ring, spacer, and clamp. [Figure 4] Top view of the upper spacer. [Figure 5] Top view of the lower spacer. [Figure 6] FIG. 10 is a top view of the lower spacer of the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] The tire vulcanizing apparatus 10 shown in FIG. 1 is an apparatus for manufacturing a pneumatic tire by vulcanizing and molding a green tire made of a plurality of rubber members and the like.

[0010] The tire vulcanizing apparatus 10 includes, as a part thereof, a mold 11 consisting of a plurality of molding members. The molding members constituting the mold 11 include a plurality of sectors 12 arranged in a cylindrical shape, a pair of upper and lower side plates 14 arranged on the inner diameter sides of the plurality of sectors 12, and a pair of upper and lower bead rings 16 provided on the inner diameter sides of the upper and lower side plates 14, respectively.

[0011] Each side plate 14 is a ring-shaped member that goes around the circumferential direction of the mold, and each bead ring 16 is also a ring-shaped member that goes around the circumferential direction of the mold.

[0012] The inner diameter surfaces of the multiple sectors 12 have molding surfaces 12a for molding the tread of a pneumatic tire. Although not shown, the molding surfaces for molding the tread have numerous protrusions formed thereon for forming grooves for the pneumatic tire. As shown in Figures 2 and 3, the lower surface of the upper side plate 14 and the upper surface of the lower side plate 14 have molding surfaces 14a for molding the sidewall of the pneumatic tire. The lower surface of the upper bead ring 16 and the upper surface of the lower bead ring 16 have molding surfaces 16a for molding the bead portion of the pneumatic tire.

[0013] 2 and 3, the side plate 14 has a molding surface 14a for molding the sidewall and a concave surface 14b on the inner diameter side of the molding surface 14a. The outer diameter surface 16b of the bead ring 16 and the like come into contact with this concave surface 14b.

[0014] The bead ring 16 is formed on its inner diameter side with an inner diameter side protrusion 16c that protrudes radially inward in the mold direction and an inner diameter side recess 16d that is recessed relative to the inner diameter side protrusion 16c. The inner diameter side recess 16d is located more inward in the mold axial direction than the inner diameter side protrusion 16c (toward the center in the vertical direction of the mold 11). The mold radial direction is the direction of arrow A in Figures 1 to 3, and the mold axial direction is the direction of arrow B in Figures 1 to 3. The mold 11 is positioned so that its axial direction B is the vertical direction.

[0015] The sector 12 is made of a metal material that is easy to process. Examples of metal materials that are easy to process and suitable for the sector 12 include aluminum and aluminum alloys. The side plates 14 and bead rings 16 are made of a metal material that is highly durable. Examples of metal materials that are highly durable and suitable for the side plates 14 include steel.

[0016] This mold 11 is held in a container (not shown) which is part of the tire vulcanization apparatus 10. The container has a conventionally well-known structure and is equipped with a radial movement device that moves the sectors 12 in the mold radial direction, an axial movement device that moves the upper side plate 14, the upper bead ring 16 and all of the sectors 12 in the mold axial direction, and a heating device that heats the mold 11 from the outside.

[0017] The mold 11 is in an open state when the upper side plate 14, the upper bead ring 16, and all of the sectors 12 are raised to positions away from the lower side plate 14 and the lower bead ring 16, and all of the spaces between the sectors 12 are open. When the mold 11 is in the open state, a tire is loaded into or removed from the interior of the mold 11. Also, when the mold 11 is in the open state, the clamps 55, 56 and the bladder 51, which will be described later, are replaced.

[0018] On the other hand, the mold 11 is in a closed state when the upper side plate 14, the upper bead ring 16, and all the sectors 12 are lowered and all the adjacent molding members are in close contact with each other. When the mold 11 is in a closed state, all the molding surfaces of the side plate 14, the bead ring 16, and the sectors 12 are integrated to form a single molding surface that molds the surface of the pneumatic tire. The position of each molding member during vulcanization molding is the position when the mold 11 is closed.

[0019] As shown in Figure 1, a bladder unit 50, which is part of the tire vulcanizing apparatus 10, is provided on the inner diameter side of the mold 11. The bladder unit 50 includes a support cylinder 52 arranged on the inner diameter side of the mold 11, and a center shaft 53 inserted inside the support cylinder 52 with its upper portion projecting above the support cylinder 52. The central axes of the support cylinder 52 and the center shaft 53 are coaxial with the central axis of the mold 11. The center shaft 53 can be moved up and down by operation of a device not shown.

[0020] An upper clamp 55, which is part of the bladder unit 50, is fixed to the top of the center shaft 53. In addition, a lower clamp 56, which is also part of the bladder unit 50, is fixed to the support cylinder 52. When the mold 11 is open, the center shaft 53 protrudes higher upward and the position of the upper clamp 55 is higher than when the mold 11 is closed.

[0021] Furthermore, the bladder unit 50 includes a bladder 51. The bladder 51 is an expandable and contractible rubber member. The bladder 51 is substantially cylindrical when stretched in the vertical direction. The bladder 51 has an upper opening edge 58 and a lower opening edge 59 at the portions that become the upper and lower ends when stretched in the vertical direction. These opening edges 58, 59 are circular when viewed from above.

[0022] Upper opening edge 58 is held around its entire circumference by upper clamp 55. Upper clamp 55 is made up of upper holding member 40 and lower holding member 41. Upper holding member 40 and lower holding member 41 are each ring-shaped members that make one revolution in the circumferential direction of the mold. As shown in FIG. 1 , upper clamp 55 holds upper opening edge 58 of bladder 51 by upper holding member 40 and lower holding member 41 sandwiching upper opening edge 58 from above and below.

[0023] Additionally, the lower opening edge 59 is held all the way around by a lower clamp 56. The lower clamp 56 is made up of an upper holding member 42 and a lower holding member 43. The upper holding member 42 and the lower holding member 43 are each ring-shaped members that make one turn in the circumferential direction of the mold. As shown in FIG. 1 , the upper holding member 42 and the lower holding member 43 sandwich the lower opening edge 59 of the bladder 51 from above and below, thereby allowing the lower clamp 56 to hold the lower opening edge 59.

[0024] An upper spacer 20 is sandwiched between the upper holding member 40 of the upper clamp 55 and the upper bead ring 16. The upper spacer 20 is fixed to the upper bead ring 16 by a fastener (not shown) such as a bolt. On the other hand, the upper spacer 20 is not fixed to the upper clamp 55.

[0025] The upper spacer 20 is a ring-shaped member that goes around the circumference of the mold. As shown in Figures 2 and 4, the inner diameter side of the upper spacer 20 is formed with an inner diameter side protrusion 21 that protrudes toward the inside in the mold diameter direction, and an inner diameter side recess 22 that is formed below the inner diameter side protrusion 21 and is recessed relative to the inner diameter side protrusion 21. The outer diameter side of the upper spacer 20 is formed with an outer diameter side protrusion 23 that protrudes toward the outside in the mold diameter direction, and an outer diameter side recess 24 that is formed above the outer diameter side protrusion 23 and is recessed relative to the outer diameter side protrusion 23.

[0026] The upper holding member 40 of the upper clamp 55 fits into the inner diameter side recess 22 of the upper spacer 20. Furthermore, the uneven portion consisting of the outer diameter side protrusion 23 and outer diameter side recess 24 of the upper spacer 20 fits into the uneven portion consisting of the inner diameter side recess 16d and inner diameter side protrusion 16c of the upper bead ring 16. As a result, the upper spacer 20 is sandwiched between the upper holding member 40 of the upper clamp 55 and the upper bead ring 16 with no gap between them.

[0027] Furthermore, a lower spacer 30 is sandwiched between the lower holding member 43 of the lower clamp 56 and the lower bead ring 16. The lower spacer 30 is fixed to the lower bead ring 16 by a fastener (not shown) such as a bolt. On the other hand, the lower spacer 30 is not fixed to the lower clamp 56.

[0028] The lower spacer 30 is a ring-shaped member that goes around the circumference of the mold. As shown in Figures 3 and 5, the inner diameter side of the lower spacer 30 is formed with an inner diameter side convexity 31 that protrudes toward the inside in the mold radial direction, and an inner diameter side concavity 32 that is formed on the inner diameter side convexity 31 and is concave relative to the inner diameter side convexity 31. The outer diameter side of the lower spacer 30 is formed with an outer diameter side convexity 33 that protrudes toward the outside in the mold radial direction, and an outer diameter side concavity 34 that is formed below the outer diameter side convexity 33 and is concave relative to the outer diameter side convexity 33.

[0029] The lower holding member 43 of the lower clamp 56 fits into the inner diameter side recess 32 of the lower spacer 30. Furthermore, the uneven portion consisting of the outer diameter side protrusion 33 and outer diameter side recess 34 of the lower spacer 30 fits into the uneven portion consisting of the inner diameter side recess 16d and inner diameter side protrusion 16c of the lower bead ring 16. As a result, the lower spacer 30 is sandwiched between the lower holding member 43 of the lower clamp 56 and the lower bead ring 16 with no gap between them.

[0030] Before vulcanization molding, a plurality of upper spacers 20 are prepared, one of which is used as part of the tire vulcanization apparatus 10. The prepared plurality of upper spacers 20 each have a different outer diameter (i.e., the diameter of the surface that contacts the bead ring 16). However, all of the upper spacers 20 have the same inner diameter (i.e., the diameter of the surface that contacts the upper clamp 55). Therefore, if the inner diameter of the tire to be vulcanized (hereinafter referred to as the "target tire") is changed, which changes the inner diameter of the bead ring 16, but the upper clamp 55 is not changed, replacing the upper spacer 20 will close the gap between the bead ring 16 and the upper clamp 55.

[0031] Furthermore, before vulcanization molding, a plurality of lower spacers 30 are prepared, and one of them is used as part of the tire vulcanization apparatus 10. The prepared plurality of lower spacers 30 each have a different outer diameter (i.e., the diameter of the surface that contacts the bead ring 16). However, all of the lower spacers 30 have the same inner diameter (i.e., the diameter of the surface that contacts the lower clamp 56). Therefore, if the inner diameter of the tire to be molded is changed, which in turn changes the inner diameter of the bead ring 16, but the lower clamp 56 is not changed, replacing the lower spacer 30 will close the gap between the bead ring 16 and the lower clamp 56.

[0032] 1, the support cylinder 52 is provided with a flow path 62 through which a heated fluid flows. The flow path 62 opens at a location between the upper clamp 55 and the lower clamp 56. The heated fluid supplied from the outside can pass through the flow path 62 and flow into the inside of the bladder 51. The flow of the fluid into the inside of the bladder 51 causes the bladder 51 to expand. For example, steam, hot water, or an inert gas is used as the fluid supplied from the outside.

[0033] The bladder 51 functions as a pressure device that expands inside the green tire to press the green tire against the inner surface of the mold 11 and apply pressure. The bladder 51 also functions as a heating device that heats the green tire because it becomes hot due to the heated fluid.

[0034] Next, a method for manufacturing a pneumatic tire will be described. First, a green tire is molded by stacking multiple rubber members and the like on a cylindrical drum. Next, the mold 11 is heated to reach the temperature required for vulcanization molding. Next, the mold 11 is opened, and the green tire is inserted into the mold 11. Next, the mold 11 is closed. Next, a heated fluid is introduced into the bladder 51, causing the bladder 51 to expand. As a result, the surface of the green tire is pressed against the inner surface of the mold 11 by the bladder 51, and the green tire is pressurized. At this time, because the fluid supplied into the bladder 51 is at a high temperature, the green tire is heated not only from the mold 11 side but also from the bladder 51 side. In this way, the green tire is pressurized to a predetermined pressure and heated to a predetermined temperature, thereby performing vulcanization molding.

[0035] After vulcanization molding has been carried out for a predetermined time, the fluid is discharged from inside the bladder 51, causing the bladder 51 to contract. After the bladder 51 has completely contracted, the mold 11 opens. The pneumatic tire is then removed from the open mold 11, completing the vulcanization molding process. After that, finishing is performed, such as removing any unnecessary rubber protrusions that have formed on the surface of the pneumatic tire, and the pneumatic tire is completed.

[0036] In the past, when the inner diameter of the tire to be molded (which may also be called the rim diameter, but hereinafter referred to as the "tire inner diameter") changed, clamps with bladders attached were prepared in advance, and the clamps and bladders were replaced as a unit when the mold was replaced. However, in this embodiment, when the tire inner diameter changes and mold 11 is replaced, clamps 55, 56 and bladders 51 are not replaced, and only spacers 20, 30 are replaced.

[0037] The spacers 20 and 30 are replaced when the mold 11 is opened, the upper clamp 55 is raised, the gap between the upper clamp 55 and the lower clamp 56 is widened, and the bladder 51 is stretched vertically to assume a cylindrical shape. The cylindrical shape of the bladder 51 makes it easy to insert and remove the lower spacer 30.

[0038] When the tire to be molded is changed to one with a larger inner diameter, the spacers 20, 30 are replaced with ones with a larger outer diameter. Also, spacers 20, 30 may be installed in places where there were no spacers 20, 30 before the change.

[0039] Furthermore, when the tire to be molded is changed to one with a smaller inner diameter, the spacers 20, 30 are replaced with ones with a smaller outer diameter. In addition, the spacers 20, 30 that were present before the change may be removed to eliminate the spacers 20, 30.

[0040] Next, the effects of this embodiment will be described. When the inner diameter of the tire to be molded is changed, the inner diameter of the bead ring 16 in the mold 11 is changed. At that time, the spacers 20, 30 are replaced with ones having a different outer diameter, thereby filling the gap between the bead ring 16 and the clamps 55, 56. Therefore, there is no need to change the clamps 55, 56.

[0041] This eliminates the need to change the clamps 55, 56, and eliminates the need to manufacture and manage a large number of different sized clamps 55, 56. Although it is necessary to prepare a large number of spacers 20, 30 with different outer diameters to accommodate the production of a large number of pneumatic tires with different inner diameters, the spacers 20, 30 are easier to design and manufacture than the clamps 55, 56, and therefore the preparation burden is lighter.

[0042] Furthermore, in cases where the bladder 51 that had been used is discarded when the clamps 55 and 56 are replaced, this embodiment reduces the frequency with which the clamps 55 and 56 need to be replaced, thereby enabling the bladder 51 to be used for a long period of time.

[0043] Next, comparative examples and examples will be described. Using the bladders and clamps listed in the "Bladder, Clamp" column, the spacers listed in the "Spacer" column, and the molds listed in the "Mold" column in Table 1, it was investigated whether the bladders, clamps, spacers, and bead rings were positioned to mold a pneumatic tire of the size listed in the "Mold" column. In Table 1, ○ indicates that the bead rings, etc. were positioned to mold a pneumatic tire of the size listed in the "Mold" column, and no problems occurred when a raw tire was actually vulcanized and molded. × indicates that the bead rings, etc. were not positioned to mold a pneumatic tire of the size listed in the "Mold" column.

[0044] When no spacer was used, as in Comparative Examples 1 to 3, a rating of "O" was obtained only when a mold corresponding to the size of the bladder and clamp was used. However, as in Example 1, when a bladder and clamp for 195 / 60R14 and a mold for 195 / 55R15 were used and a spacer for 1-inch expansion (i.e., a spacer having an outer diameter 1 inch larger than the outer diameter of the clamp) was inserted between the bead ring and the clamp, a rating of "O" was obtained. Furthermore, when a bladder and clamp for 185 / 70R13 and a mold for 195 / 55R15 were used and a spacer for 2-inch expansion (i.e., a spacer having an outer diameter 2 inches larger than the outer diameter of the clamp) was inserted between the bead ring and the clamp, a rating of "O" was obtained.

[0045] [Table 1]

[0046] The above-described embodiments are merely examples, and the scope of the invention is not limited thereto. Various modifications, substitutions, omissions, etc. can be made to the above-described embodiments without departing from the spirit of the invention. Several modified examples will be described below, and any one of the modified examples may be applied to the above-described embodiments, or any two or more of the modified examples may be applied in combination.

[0047] <Change example 1> Either or both of the upper spacer and the lower spacer may be divided into a plurality of parts in the circumferential direction of the mold.

[0048] For example, the lower spacer 130 in Figure 6 is divided into two lower spacer pieces 130a. When viewed from above, one lower spacer piece 130a forms an arc of 180°, and the two lower spacer pieces 130a together form a circle of 360°.

[0049] When inserting this lower spacer 130 between the lower clamp 56 and the lower bead ring 16, the worker inserts the lower spacer pieces 130a from both the left and right sides under the bladder 51. Then, the worker combines the two lower spacer pieces 130a between the lower clamp 56 and the lower bead ring 16 to complete one lower spacer 130.

[0050] By dividing the lower spacer 130 into two pieces in this way, the worker can easily place the lower spacer 130 under the bladder 51 even when the bladder 51 remains inflated to the side.

[0051] The lower spacer may be divided into three or more pieces, and the upper spacer may be divided into a plurality of pieces.

[0052] <Change example 2> In the above embodiment, the upper spacer 20 and the lower spacer 30 were each fixed to the bead ring 16, but the upper spacer 20 may be fixed to the upper retaining member 40 of the upper clamp 55 by a fastener, and the lower spacer 30 may be fixed to the lower retaining member 43 of the lower clamp 56 by a fastener.

[0053] Furthermore, the lower spacer 30 may simply rest on the lower bead ring 16 by its own weight without being fixed to another member by a fixture. The upper spacer 20 may simply rest on the upper clamp 55 by its own weight without being fixed to another member by a fixture. [Explanation of symbols]

[0054] 10... tire vulcanizing apparatus, 11... mold, 12... sector, 12a... molding surface, 14... side plate, 14a... molding surface, 14b... concave surface, 16... bead ring, 16a... molding surface, 16b... outer diameter surface, 16c... inner diameter side convex, 16d... inner diameter side concave, 20... upper spacer, 21... inner diameter side convex, 22... inner diameter side concave, 23... outer diameter side convex, 24... outer diameter side concave, 30... lower spacer, 31... inner diameter side, 3 2...inner diameter side concave, 33...outer diameter side convex, 34...outer diameter side concave, 40...upper holding member, 41...lower holding member, 42...upper holding member, 43...lower holding member, 50...bladder unit, 51...bladder, 52...support tube, 53...center shaft, 55...upper clamp, 56...lower clamp, 58...upper opening edge, 59...lower opening edge, 62...flow path, 130...lower spacer, 130a...lower spacer piece

Claims

1. a mold having a molding surface for molding the tire surface; a bladder that can be inflated toward the molding surface of the mold; and two clamps that hold the top and bottom of the bladder respectively on the radially inner side of the mold, bead rings are provided at the upper and lower radially inner ends of the mold, each extending around the circumferential direction of the mold; The bladder has an opening edge at each of the top and bottom that extends around the periphery of the mold, In a tire vulcanizing apparatus, the clamps each hold the opening edge of the bladder over one circumference in the mold circumferential direction at the top and bottom, respectively, A spacer that makes one turn in the circumferential direction of the mold is sandwiched between the bead ring and the clamp, the clamp includes an upper holding member and a lower holding member that sandwich the opening edge of the bladder from above and below, The spacer is not fixed to the clamp. A tire vulcanizing apparatus characterized by:

2. The tire vulcanizing apparatus according to claim 1 , wherein the spacer is divided into a plurality of pieces in the circumferential direction of the mold.

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