Tire vulcanization method

Abstract

The present application provides a tire vulcanization method that suppresses rubber bite and wear damage of a vulcanization mold. The tire vulcanization method is a green tire vulcanization method including a mounting process (S1) in which a green tire (50a) is mounted inside a vulcanization mold (2) in a state in which the vulcanization mold (2) is opened. The mounting process (S1) includes: a green tire pressing process (S1c) in which a pair of side mold (5) is moved to a state in which they are closer to each other in a tire axial direction than a reference position (P), thereby compressing a tire axial width of a side portion (52) of the green tire (50a); a positioning process (S1d) in which the pair of side mold (5) is moved to the reference position (P) and stopped after a prescribed time elapses from the green tire pressing process (S1c); and a tread mold moving process (S1e) in which a tread mold (4) is moved in a tire radial direction and positioned at the reference position (P) after the positioning process (S1d).

Description

TECHNICAL FIELD

[0001] The present application relates to a tire vulcanization method. BACKGROUND

[0002] A tire vulcanization molding method in which a green tire is inserted into a mold is described in Patent Literature 1. The mold has a plurality of sector pieces arranged in a circular shape and a pair of side plates provided on the inner diameter side of the circle formed by the sector pieces.

[0003] As the tire vulcanization molding method, when the sector pieces and the side plates are separated, the green tire is inserted into the mold with the bead portion of the green tire positioned at a position on the tire equatorial side than a molding position. Then, while or after the sector pieces and the side plates are closed, the bead portion of the green tire is moved to the molding position to perform vulcanization molding. In such a molding method, the green tire can be inhibited from being bitten into between the sector pieces and the side plates.

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2018-15908

[0005] However, in order to move the bead portion to the molding position as described above, it is necessary to move the side plates to the outside in the tire axial direction (this movement is referred to as "side plate movement"). Before the side plate movement, since the sector pieces and the side plates are closed, there is a problem that when the side plate movement is performed, the side plates and the sector pieces are rubbed to generate a wear damage. SUMMARY

[0006] The present application was completed in view of the above actual situations, and its main object is to provide a tire vulcanization method capable of inhibiting a green tire from being bitten into a vulcanization mold (hereinafter, sometimes referred to as "rubber biting") and capable of inhibiting a wear damage of the vulcanization mold.

[0007] The present application is a tire vulcanization method for vulcanizing a green tire using a vulcanization mold including a tread mold that shapes a tread portion of a green tire and a pair of side mold that shapes a pair of side portions of the green tire, wherein a mounting step of mounting the green tire inside the vulcanization mold in a state where the vulcanization mold is opened and a vulcanization step of vulcanizing the green tire in a closed state where the tread mold and the pair of side mold are disposed at a predetermined reference position are included, and the mounting step includes a green tire pressing step of moving at least one of the pair of side mold to make the pair of side mold closer to each other in a tire axial direction than the reference position after the green tire is mounted to the vulcanization mold to compress a tire axial width of the pair of side portions of the green tire, a positioning step of stopping the pair of side mold at the reference position after a prescribed time elapses from the green tire pressing step, and a tread mold moving step of moving the tread mold in a tire radial direction to be positioned at the reference position after the positioning step.

[0008] The tire vulcanization method of the present application is preferably such that the tread mold includes a plurality of segments arranged in a tire circumferential direction, and the tread mold moving step moves the plurality of segments to an inner side in a tire radial direction.

[0009] The tire vulcanization method of the present application is preferably such that the split position of the pair of side mold and the tread mold is a position within 5% of a tire cross-sectional height from an inner or outer position in a tire radial direction from a maximum width position of a vulcanized tire.

[0010] The tire vulcanization method of the present application is preferably such that the split position of the pair of side mold and the tread mold is a maximum width position of a vulcanized tire.

[0011] The tire vulcanization method of the present application can suppress rubber biting and wear damage of the vulcanization mold by adopting the above-described structure. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a side view conceptually showing one embodiment of a vulcanization apparatus of the present application.

[0013] Figure 2 (a) and (b) of FIG. 1 are cross-sectional and partial side views showing a tire formed in the present application.

[0014] Figure 3 is an enlarged cross-sectional view showing a main part of the vulcanization apparatus of Figure 1

[0015] Figure 4 ​It is a cross-sectional view showing the vulcanizing mold in its closed state along with the tire.

[0016] Figure 5 (a) is a flowchart of the tire vulcanization method, and (b) is a flowchart of the installation process.

[0017] Figure 6 (a) and (b) are sectional views that conceptually illustrate the installation process.

[0018] Figure 7 (a) and (b) are sectional views that conceptually illustrate the installation process.

[0019] Label Explanation

[0020] 2: Vulcanizing mold; 4: Tread mold; 5: Sidewall mold; 50a: Green tire; 52: Sidewall; P: Reference position; S1: Installation process; S1c: Green tire pressing process; S1d: Positioning process; S1e: Tread mold moving process. Detailed Implementation

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0022] Figure 1 This is a cross-sectional view conceptually illustrating one embodiment of the vulcanizing apparatus 1 used in the tire vulcanizing method of the present invention. Figure 2 (a) and (b) are a cross-sectional and side view of one embodiment of a vulcanized tire (hereinafter sometimes referred to as "tire") 50 formed by vulcanizing device 1. The tire 50 is formed by vulcanizing a green tire 50a ( Figure 6 It is obtained by vulcanization (as shown).

[0023] like Figure 2 As shown in (a) and (b), the tire 50 of this embodiment is used, for example, in a four-wheel drive vehicle such as an SUV. The tire 50 includes, for example, a tread portion 51; sidewall portions 52 extending from the two outer sides of the tread portion 51 in the tire axial direction inwards towards the inner side in the tire radial direction; and a bead portion 53 disposed on the inner side of each sidewall portion 52 in the tire radial direction. Figure 2 (a) and (b) show the sidewall portion 52 and the bead portion 53 of one side.

[0024] A tread pattern is formed on the tread portion 51, in which multiple tread blocks R extending circumferentially along the tire are arranged axially along the tire. The tread pattern includes a shoulder block row R1 located on the outermost side of the tire axially.

[0025] In the present embodiment, in order to improve the traction performance, the appearance performance in off-road, the shoulder block row R1 is formed in a position extending to the inner side in the tire radial direction than the tire end Te, and also in the outer side region Y in the tire radial direction of the side portion 52. The shoulder block row R1 protrudes from the surface S of the side portion 52. The shape, the protrusion height, and the like of the shoulder block row R1 can be appropriately set according to the tire size and the like. Note that the tire 50 is not limited to this manner.

[0026] As Figure 1 indicated, the vulcanization device 1 of the present embodiment includes a vulcanization mold 2 in which the green tire 50a is installed inside, and a device main body 3 that supports the vulcanization mold 2 to be openable and closable.

[0027] Figure 3 is an enlarged view of a main part of Figure 1 . As indicated in Figure 1 and Figure 3 , the vulcanization mold 2 includes a ring-shaped tread mold 4 whose diameter is expandable and contractable in the tire radial direction, a pair of side molds 5, and a vulcanization bladder of a publicly known configuration, not shown. In the vulcanization mold 2 of the present embodiment, the green tire 50a is installed in a horizontal manner. Therefore, in the present specification, in the vulcanization device 1, the tire axial direction is the direction of the vertical (up and down). In addition, the tire radial direction and the tire circumferential direction are the directions along the horizontal.

[0028] In the present embodiment, the tread mold 4 is formed of a plurality of segments 4A arranged in the tire circumferential direction. Each segment 4A is held in a publicly known fan 6, for example, in a replaceable manner. In the segment 4A, a molding surface for forming the tread pattern is arranged.

[0029] The pair of side molds 5 of the present embodiment includes an upper side side mold 5U and a lower side side mold 5L arranged below it. In the pair of side molds 5, a molding surface for forming the side portion 52 and the bead portion 53 (indicated in Figure 2 ) is arranged, respectively. Each side mold 5U, 5L is divided into a bead ring 5a for forming the bead portion 53 and a side plate 5b for forming the side portion 52, for example, respectively. In addition, each side mold 5U, 5L is not limited to this manner, and can integrally form the side portion 52 and the bead portion 53, for example.

[0030] In the present embodiment, as Figure 2As shown in (a), the split positions Q of the pair of side mold 5 and the tread mold 4 are located at positions at least more inside in the tire radial direction than the tire radial direction innermost end Rle of the shoulder block row Rl. It is preferable that the split positions Q are positions within 15% of the tire cross-sectional height H from the tire 50 maximum width position M to the inside and outside in the tire radial direction. It is more preferable that the split positions Q are positions within 10% of the tire cross-sectional height H from the maximum width position M to the inside and outside in the tire radial direction. It is further preferable that the split positions Q are positions within 5% of the tire cross-sectional height H from the maximum width position M to the inside and outside in the tire radial direction. Such a vulcanization mold 2 enables the tire 50 to be smoothly extracted from the vulcanization mold. The split positions Q are more preferably the maximum width position M of the tire 50.

[0031] As shown in (a), the split positions Q of the pair of side mold 5 and the tread mold 4 are located at positions at least more inside in the tire radial direction than the tire radial direction innermost end Rle of the shoulder block row Rl. It is preferable that the split positions Q are positions within 15% of the tire cross-sectional height H from the tire 50 maximum width position M to the inside and outside in the tire radial direction. It is more preferable that the split positions Q are positions within 10% of the tire cross-sectional height H from the maximum width position M to the inside and outside in the tire radial direction. It is further preferable that the split positions Q are positions within 5% of the tire cross-sectional height H from the maximum width position M to the inside and outside in the tire radial direction. Such a vulcanization mold 2 enables the tire 50 to be smoothly extracted from the vulcanization mold. The split positions Q are more preferably the maximum width position M of the tire 50. Figure 1 Figure 3 As shown in (a), the split positions Q of the pair of side mold 5 and the tread mold 4 are located at positions at least more inside in the tire radial direction than the tire radial direction innermost end Rle of the shoulder block row Rl. It is preferable that the split positions Q are positions within 15% of the tire cross-sectional height H from the tire 50 maximum width position M to the inside and outside in the tire radial direction. It is more preferable that the split positions Q are positions within 10% of the tire cross-sectional height H from the maximum width position M to the inside and outside in the tire radial direction. It is further preferable that the split positions Q are positions within 5% of the tire cross-sectional height H from the maximum width position M to the inside and outside in the tire radial direction. Such a vulcanization mold 2 enables the tire 50 to be smoothly extracted from the vulcanization mold. The split positions Q are more preferably the maximum width position M of the tire 50.

[0032] In the present embodiment, the axial movement member 3A includes an upper plate 7 that supports the tread mold 4, a lower plate 8 that places the lower side side mold 5L, and upper and lower side base stands 9U, 9L that are supported to a frame not shown. The lower side base stand 9L is disposed below the lower plate 8 and supports the lower plate 8. The lower side base stand 9L is fixed to a floor plate 16 disposed below it. The upper side base stand 9U is disposed at a position above the upper plate 7. The upper side base stand 9U supports, for example, a ceiling plate 15 disposed above it. The vulcanization bladder is disposed between the upper plate 7 and the lower plate 8.

[0033] In the present embodiment, the axial movement member 3A substantially includes a center mechanism 10 that extends along the rotation axis 50c of the tire 50. The rotation axis 50c of the tire 50 is located at the center of the upper plate 7, the lower plate 8, and the upper and lower side base stands 9U, 9L.

[0034] The center mechanism 10 includes, for example, a first lifting member 11, a second lifting member 12, a third lifting member 13, and a fourth lifting member 14. In the present embodiment, the first to fourth lifting members 11 to 14 are each formed of a cylinder (rod cylinder) of a known configuration.

[0035] ​In this embodiment, the central mechanism 10 includes a connecting portion 17, an upper support cylinder 18, an upper lifting shaft 19, a lifting plate 20, a lower support cylinder 21, and a central column 22. The connecting portion 17 is, for example, disposed at the lower end of the rod of the fourth lifting member 14. In this embodiment, the connecting portion 17 supports the first lifting member 11. The upper support cylinder 18 is, for example, cylindrical and disposed at the lower end of the connecting portion 17. The upper support cylinder 18, for example, holds the upper plate 7 with its lower end. In this embodiment, the upper lifting shaft 19 extends axially along the tire through the central hole of the upper support cylinder 18 and is connected to the lower end of the rod of the first lifting member 11. An upper sidewall mold 5U is mounted at the lower end of the upper lifting shaft 19, for example, via a connecting portion 23. The lifting plate 20 is, for example, supported at the upper end of the rod of the second lifting member 12. In this embodiment, the lifting plate 20 supports the third lifting member 13. The lower support cylinder 21 is, for example, cylindrical and stands upright from the lifting plate 20. In this embodiment, the upper end of the lower support cylinder 21 supports the lower sidewall mold 5L via a bracket 24. The center post 22 extends axially along the tire through the center hole of the lower support cylinder 21 and is connected to the upper end of the rod of the third lifting member 13. An upper handlebar ring 25U is, for example, installed at the upper end of the center post 22 to hold the upper end of the vulcanizing airbag. A lower handlebar ring 25L is disposed below the upper handlebar ring 25U to hold the lower end of the vulcanizing airbag. The lower handlebar ring 25L is mounted on the upper surface of the lower sidewall mold 5L.

[0036] The top plate 15 supports, for example, the fourth lifting member 14. The bottom plate 16 supports, for example, the second lifting member 12.

[0037] Therefore, by extending or retracting the rod of the first lifting member 11, for example, the upper sidewall mold 5U can move relative to the upper plate 7 inward or outward along the tire axial direction. By extending or retracting the rod of the second lifting member 12, for example, the lower sidewall mold 5L can move relative to the lower plate 8 inward or outward along the tire axial direction. By extending or retracting the rod of the third lifting member 13, for example, the tire axial position of the upper end of the vulcanizing airbag (the upper handle 25U) can be determined. By extending or retracting the rod of the fourth lifting member 14, for example, the upper plate 7 can move integrally with the tread mold 4 inward or outward along the tire axial direction.

[0038] By extending the rod of the fourth lifting member 14, for example, the tread mold 4 can be in a lowered state PL where the lower surface of the sector member 6 contacts the lower plate 8. Figure 1 , 3 (As shown) and the fan-shaped part 6 moving upwards from the lower plate 8 in standby state PU ( Figure 6moves up and down between the expanded state (shown in (a) of FIG. 4) and the contracted state (shown in (b) of FIG. 4). In addition, by elongation of the rod of the 4th lifter 14, the upper side of the sidewall mold 5U moves integrally with the upper plate 7 inward and outward in the tire axial direction. In the lowered state PL, the rod of the 1st lifter 11 is elongated, and the upper side of the sidewall mold 5U moves relatively to the upper plate 7 inward in the tire axial direction.

[0039] In the present embodiment, the diameter expanding / contracting member 3B includes a lifting plate 31, a cylindrical actuator 32 supported to the lifting plate 31, and a 5th lifter 33 (shown in (a) of FIG. 4). A guide portion 32A inclined toward the lower side and toward the tire radial direction outer side is provided to the inner peripheral surface of the actuator 32. The lifting plate 31 is configured to be relatively movable up and down with respect to the upper plate 7, for example, by the 5th lifter 33. The 5th lifter 33 is configured by a known cylinder (rod cylinder), for example. Figure 3

[0040] Figure 4 is Figure 3 is shown in (a) of FIG. 4. As shown in (a) of FIG. 4, in the segment 4A, the guide pin 35 of the upper end of the sector 6 is guided by the guide groove 36 of the upper plate 7, and thereby held to the upper plate 7 in a manner that is movable in the tire radial direction. The outer surface of the sector 6 in the tire radial direction is provided with a guide portion 6A of the same inclination as the guide portion 32A. Figure 4

[0041] Therefore, by elongation and contraction of the rod of the 5th lifter 33, the actuator 32 is relatively raised or lowered with respect to the upper plate 7. Thereby, each segment 4A is moved in the tire radial direction, and the diameter of the tread mold 4 can be expanded or contracted. After the diameter is expanded, the upper plate 7 is raised by the 4th lifter 14, and thereby the tread mold 4 in the expanded state is raised integrally with the upper side of the sidewall mold 5U (shown in (a) of FIG. 4). This state is an open state in which the green tire 50a can be installed inside the vulcanization mold 2 and the vulcanized tire 50 can be taken out from the inside. Figure 6

[0042] The vulcanization device 1 of the present embodiment preferably further includes a control member (omitted from the drawing) for operating the 1st to 5th lifters 11, 12, 13, 14, 33. The control member is preferably a computer or the like, for example, and stores the operation steps, operation amounts, and the like of each lifter.

[0043] As Figure 1 ​​​As shown, a first detection unit 37 and a second detection unit 38 are preferably provided in the vulcanizing apparatus 1. The first detection unit 37, for example, detects the relative axial movement distance of the upper sidewall mold 5U relative to the upper plate 7. The second detection unit 38 detects the relative axial movement distance of the lower sidewall mold 5L relative to the lower plate 8. The first and second detection units 37 and 38 employ various known measuring instruments or sensors.

[0044] Next, the tire vulcanization method using vulcanization device 1 will be described. Figure 5 (a) is a flowchart of the tire vulcanization method of this embodiment. Figure 5 As shown in (a), the tire vulcanization method of this embodiment includes an installation step S1 in which a green tire 50a is installed inside the vulcanization mold 2 and a vulcanization step S2 in which the green tire 50a is vulcanized while the vulcanization mold 2 is in a closed state.

[0045] Figure 5 (b) is a flowchart of the installation process S1 in this embodiment. Figure 5 As shown in (b), the installation process S1 in this embodiment includes a green tire pressing process S1c, a positioning process S1d, and a tread mold moving process S1e. Additionally, the installation process S1 may include, for example, a placement process S1a and a lowering process S1b.

[0046] Figure 6 and Figure 7 This is a cross-sectional view conceptually illustrating installation procedure S1. For example... Figure 6 and Figure 7 As shown, in the installation process S1, the placement process S1a is performed first. In the placement process S1a of this embodiment, as follows... Figure 6 As shown in (a), the vulcanizing mold 2 is in the open state. Specifically, at least the tread mold 4, the fan-shaped part 6, and the upper sidewall mold 5U are positioned above the uppermost end of the green tire 50a or tire 50, which is placed on the lower sidewall mold 5L. In the loading process S1a, the green tire 50a is installed in the vulcanizing mold 2 in the open state. Specifically, the bead portion 53 below the green tire 50a is placed on the sidewall mold 5L, which is mounted on the lower side of the lower plate 8. At this time, the lower sidewall mold 5L is located at the reference position P. The reference position P is the predetermined position of the vulcanizing mold 2 when the green tire 50a is vulcanized.

[0047] Next, the descent process S1b is performed. For example... Figure 6As shown in (b), in the lowering process S1b of this embodiment, the rod of the fourth lifting member 14 extends, and the upper sidewall mold 5U descends together with the upper plate 7. In the lowering process S1b, for example, the upper sidewall mold 5U descends to the reference position P. At this time, the bead portion 53 above the green tire 50a is arranged in contact with the upper sidewall mold 5U.

[0048] Next, the fetal pressing process S1c is performed. For example... Figure 7 As shown in (a), in the green tire pressing process S1c of this embodiment, the axial width of the pair of sidewall portions 52 of the green tire 50a is compressed. In the green tire pressing process S1c, for example, at least one of the pair of sidewall molds 5U and 5L is moved so that the pair of sidewall molds 5U and 5L are close to each other in the tire axial direction relative to the reference position P. Specifically, by extending the rod of the first lifting member 11, the upper lifting shaft 19 is lowered, and the upper sidewall mold 5U moves downward relative to the upper plate 7. In addition, by extending the rod of the second lifting member 12, the lower support cylinder 21 is extended, and the lower sidewall mold 5L moves upward relative to the lower plate 8. As a result, the axial width of the sidewall portion 52 of the green tire 50a is compressed.

[0049] Next, the positioning process S1d is performed. For example... Figure 6 As shown in (b), in this embodiment, during the positioning process S1d, after a predetermined time has elapsed since the green tire pressing process S1c, a pair of sidewall molds 5U and 5L move to the reference position P and stop. The upper sidewall mold 5U moves to the reference position P, for example, by retracting the rod of the first lifting member 11. The lower sidewall mold 5L moves to the reference position P, for example, by retracting the rod of the second lifting member 12. At this time, the green tire 50a maintains the state where the axial width of the tire sidewall portion is compressed by the green tire pressing process S1c (indicated by dashed lines).

[0050] Next, the tread mold moving process S1e is performed. For example... Figure 7 As shown in (b), in the tread mold moving process S1e of this embodiment, the tread mold 4 is moved along the tire radius direction and positioned at the reference position P. In this embodiment, the tread mold 4 is moved by the fifth lifting member 33 ( Figure 4 The rod (shown) extends and moves inward in the radial direction of the tire, and is positioned at the reference position P. This suppresses friction between the sidewall molds 5 and the tread molds 4 in the tire axial direction, thus preventing wear damage. Furthermore, since the axial width of the sidewall portion 52 of the green tire 50a has been compressed by the green tire pressing process S1c, rubber biting between the tread mold 4 and the sidewall molds 5U and 5L is suppressed.

[0051] In the tread mold moving step S1e, the vulcanization mold 2 becomes a closed state in which each of the constituent parts is disposed at the reference position P. In the closed state J1, the segments 4A, 4A and the segments 4A and the upper and lower side mold 5U, 5L are pressed against each other with a strong force.

[0052] Next, the vulcanization step S2 is performed. The vulcanization step S2 of the present embodiment is performed by a publicly known method using the vulcanization bladder.

[0053] The above describes a particularly preferred embodiment of the present application, but the present application is not limited to the illustrated embodiment and can be modified into various modes to be implemented.

Claims

1. A tire vulcanization method, the tire vulcanization method being a method for vulcanizing a green tire using a vulcanization mold, the vulcanization mold comprising: a tread mold for shaping a tread portion of the green tire; and a pair of sidewall molds for shaping a pair of sidewall portions of the green tire, wherein, The tire vulcanization method includes the following steps: The installation process involves installing the green tire inside the vulcanizing mold while the mold is open; and The vulcanization process involves vulcanizing the green tire in a closed state, with the tread mold and the pair of sidewall molds positioned at predetermined reference locations. The installation process includes the following steps: In the green tire pressing process, after the green tire is installed in the vulcanizing mold, at least one of the pair of sidewall molds is moved so that the pair of sidewall molds are closer to each other in the tire axial direction than the reference position, thereby compressing the tire axial width of the pair of sidewall portions of the green tire. The positioning process involves moving the pair of tire sidewall molds to the reference position and stopping after a predetermined time has elapsed since the green tire pressing process. as well as In the tread mold moving process, after the positioning process, the tread mold is moved along the tire radius direction and positioned at the reference position. In the positioning process, the pair of sidewall molds are moved in such a way that they are separated from each other in the axial direction of the tire.

2. The tire vulcanization method according to claim 1, wherein, The tread mold comprises multiple sections arranged along the circumference of the tire. The tread mold moving process moves the multiple sections inward toward the radial direction of the tire.

3. The tire vulcanization method according to claim 1 or 2, wherein, The separation position of the pair of sidewall molds and the tread mold is within 15% of the tire cross-sectional height, from the maximum width of the vulcanized tire towards the tire radius.

4. The tire vulcanization method according to claim 1 or 2, wherein, The separation position of the pair of sidewall molds and the tread mold is within 5% of the tire cross-sectional height, from the maximum width of the vulcanized tire towards the tire radius.

5. The tire vulcanization method according to claim 3, wherein, The separation position between the pair of sidewall molds and the tread mold is the maximum width position of the vulcanized tire.

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