Method for cleaning tire vulcanization molds

Abstract

To provide a cleaning method for tire vulcanization mold that enables cleaning of tire vulcanization molds without installing new cleaning equipment.SOLUTION: A method for cleaning a tire vulcanizing mold includes a separating step in which, after a tire has been vulcanized and molded, at least one mold is separated to a cleaning position where the outer surface of the tire is separated from a tire molding surface and spew formed on the tire contacts the tire molding surface, and a rotating step in which the tire held by a bladder is rotated in the tire circumference direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a method for cleaning a tire vulcanization mold.

Background Art

[0002] Patent Document 1 discloses a cleaning device that sucks residues such as spues remaining on the tire forming surface of a tire vulcanization mold. By cleaning the tire forming surface with this cleaning device, it is possible to suppress the mixing of residues during the vulcanization molding of the tire.

[0003] However, depending on the size of the cleaning device, there is a risk that the cleaning device cannot be installed near the tire vulcanization mold. In addition, the introduction of the cleaning device is costly.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a method for cleaning a tire vulcanization mold that can clean the tire vulcanization mold without newly installing a cleaning device.

Means for Solving the Problems

[0006] The method for cleaning a tire vulcanization mold according to the present disclosure includes a separation step of separating at least one mold until the outer surface of the tire moves away from the tire forming surface and the spue formed on the tire comes into contact with the tire forming surface after the vulcanization molding of the tire, and a rotation step of rotating the tire held by a bladder in the circumferential direction of the tire.

Brief Description of the Drawings

[0007] [Figure 1] A schematic diagram showing a cross-section of a vulcanizing apparatus along the tire meridian in one embodiment. [Figure 2] Flowchart showing a method for cleaning a tire vulcanization mold according to the same embodiment. [Figure 3] Figure showing the rotation process in the same embodiment. [Figure 4] This figure shows the tire removal process in the same embodiment. [Modes for carrying out the invention]

[0008] [Vulcanizing equipment] First, an example of the configuration of a vulcanizing apparatus 100 for vulcanizing unvulcanized tires will be explained with reference to Figure 1. Note that in each figure (and similarly in Figures 2 to 4), the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios, and the dimensional ratios between each drawing do not necessarily match either.

[0009] In each figure, the first direction D1 is the tire axis direction D1, which is parallel to the tire rotation axis of the pneumatic tire T (hereinafter also simply referred to as "tire T"), and the second direction D2 is the tire radial direction D2, which is the diameter direction of tire T. The direction around the tire rotation axis is called the tire circumferential direction.

[0010] In the radial direction D2 of the tire, the inner side is closer to the tire rotation axis, and the outer side is further from the tire rotation axis. The tire meridian cross section is a cross section that includes the tire rotation axis and is perpendicular to the tire equatorial plane S1, and the tire equatorial plane S1 is a plane that is perpendicular to the tire rotation axis and is located at the center of the tire axial direction D1.

[0011] Figure 1 is a schematic diagram showing a cross-section of the vulcanizing apparatus 100 along the tire meridian. The vulcanizing apparatus 100 of this embodiment comprises a tire vulcanizing mold 1 (hereinafter sometimes simply referred to as "vulcanizing mold 1"), a container 2 that holds the vulcanizing mold 1, a tire vulcanizing bladder 3 (hereinafter sometimes simply referred to as "bladder 3") which is a rubber bag, and a central mechanism 4 provided in the center of the vulcanizing mold 1. In Figure 1, the vulcanizing mold 1 is in the closed position, and the tire T (unvulcanized tire) is set with the tire axis direction D1 facing up and down. In Figure 1, the right direction is the outside of the tire radial direction D2, and the left direction is the inside of the tire radial direction D2.

[0012] The vulcanizing mold 1 comprises a tread mold 11 for forming the tread of the tire T, an upper side mold 12 and a lower side mold 13 for forming the sidewall of the tire T, and bead rings 14 and 15 into which the bead portion of the tire T is fitted. The tread mold 11 and the side molds 12 and 13 are collectively referred to as the mold 10. The tread mold 11 is composed of multiple sectors divided in the circumferential direction of the tire, and in the closed state, these sectors come together to form a ring. The vulcanizing mold 1 according to this embodiment is a segmented mold equipped with such a segmented type tread mold 11.

[0013] The vulcanization mold 1 includes a tire molding surface 16 that contacts the outer surface of the set tire T. The tire molding surface 16 includes the inner surface of the tread mold 11 and the inner surfaces of the side molds 12 and 13. Although not shown in the figure, the inner surface of the tread mold 11 is provided with irregularities for forming the tread pattern of the tire T.

[0014] The vulcanization mold 1 is equipped with vent holes 17 for discharging air interposed between the outer surface of the unvulcanized tire and the tire molding surface 16 during vulcanization molding. The vent holes 17, also called vent holes, are formed to open into the tire molding surface 16. From the viewpoint of enhancing the cleaning effect of the tire molding surface 16, which will be described later, it is preferable that the vent holes 17 provided in the side molds 12 and 13 be arranged in four or more rows along the tire radial direction D2, and that each row be arranged in six or more holes along the tire circumferential direction.

[0015] The vulcanizing apparatus 100 is equipped with an exhaust line (not shown) that communicates with the ventilation holes 17. During vulcanization molding, excess air between the outer surface of the unvulcanized tire and the tire molding surface 16 is discharged to the outside through the ventilation holes 17 and the exhaust line. At this time, a portion of the unvulcanized tire enters the ventilation holes 17, and whisker-like rubber protrusions called spews are formed on the outer surface of the tire T. The ventilation holes 17 shown in Figure 1 are schematic representations and differ from the actual size and number. The same applies to the spews SP (see Figures 3 and 4).

[0016] Container 2 comprises a plurality of segments 21, each corresponding to a sector of the tread mold 11, and an outer ring 22 positioned outside the segments 21 in the tire radial direction D2. The tread mold 11 is held by the segments 21. The outer circumferential surfaces of the segments 21 and the inner circumferential surfaces of the outer ring 22 that engage with them are formed by tapered surfaces having the same inclination. These tapered surfaces are each inclined downwards and outwards in the tire radial direction D2. The tread mold 11 is configured to move freely in the tire radial direction D2 as the outer ring 22 moves up and down.

[0017] The container 2 includes an upper platen 23 that supports the upper side mold 12, a lower platen 24 that supports the lower side mold 13, and an arm 25 that supports the outer ring 22. The upper platen 23 is configured to be movable up and down. On the lower surface of the upper platen 23, the segment 21 is slidably supported along the tire diameter direction D2. The arm 25 is attached to a guide 26 erected on the upper surface of the upper platen 23 so as to be movable up and down. When the arm 25 moves up and down relative to the guide 26, the outer ring 22 moves up and down relative to the segment 21, and each sector held by the segment 21 moves in the tire diameter direction D2.

[0018] The vulcanization molding of the tire T is performed in the mold closed state shown in FIG. 1. The container 2 has a heat source such as an electric heater or a steam jacket, and the vulcanization mold 1 maintained at a high temperature by it heats the unvulcanized tire from the outside. When the vulcanization molding is completed, the tread mold 11 is expanded in diameter (each sector is moved to the outside in the tire diameter direction D2) by the mechanism of the container 2 described above, and the tread mold 11 and the upper side mold 12 are raised to shift to the mold open state (see FIG. 4).

[0019] The bladder 3 is disposed inside the unvulcanized tire (tire T) set in the vulcanization mold 1. The bladder 3 expands and deforms when a vulcanization medium described later is supplied, and contracts and deforms when the vulcanization medium filled therein is discharged. In the vulcanization process, the unvulcanized tire is pressed against the tire molding surface 16 by the expanded and deformed bladder 3. The bladder 3 is supported by the central mechanism 4. More specifically, the upper end portion of the bladder 3 is supported by the upper clamp 42 of the central mechanism 4, and the lower end portion of the bladder 3 is supported by the lower clamp 43 of the central mechanism 4.

[0020] The vulcanizing device 100 includes a supply line and a discharge line (not shown) that communicate with the inside of the bladder 3. The supply line supplies a vulcanization medium to the inside of the bladder 3, and the discharge line discharges the vulcanization medium filled in the inside of the bladder 3 to the outside.

[0021] The central mechanism 4 includes a center post 41 that extends in the vertical direction (tire axis direction D1) at the center of the vulcanizing mold 1. The center post 41 is spaced apart inward in the tire diameter direction D2 from the vulcanizing mold 1. An upper clamp 42 and a lower clamp 43 are attached to the center post 41. At least a part of each of the upper clamp 42 and the lower clamp 43 is configured to be detachable from the center post 41 together with the bladder 3.

[0022] The central mechanism 4 includes a cylindrical portion 44 that extends downward from the lower clamp 43. The cylindrical portion 44 is provided concentrically with the center post 41.

[0023] The tire equatorial plane S2 (see FIG. 3) in the mold open state is preferably shifted upward with respect to the tire equatorial plane S1 in the mold closed state. Thereby, it is possible to suppress the unvulcanized tire from contacting the lower side mold 13 and being vulcanized before mold closing. The unvulcanized tire (tire T) is pressed downward by the upper side mold 12 in the mold closed state and contacts the lower side mold 13. The shift amount G1 is preferably 5 mm or more and 15 mm or less. In the present embodiment, the shift amount G1 is, for example, 10 mm.

[0024] The vulcanizing apparatus 100 includes a rotation mechanism 5 that rotates the tire T held by the bladder 3 in the tire circumferential direction. The rotation mechanism 5 includes a rotation driving unit 51 and a rotation transmission unit 52 that transmits the output of the rotation driving unit 51 to the central mechanism 4. In the present embodiment, the rotation mechanism 5 rotates the central mechanism 4.

[0025] The rotary drive unit 51 is, for example, a stepping motor or a servo motor. In this embodiment, the rotary transmission unit 52 includes a first gear 521 fixed to the cylindrical part 44 and a second gear 522 provided between the rotary drive unit 51 and the first gear 521. The first gear 521 is, for example, an annular spur gear. The second gear 522 is, for example, a gear in which a face gear 522a and a spur gear 522b are integrated. The rotary drive unit 51 and the second gear 522 are fixed to, for example, a lifting transmission unit 62, which will be described later. Note that the rotary mechanism 5 is not limited to the above.

[0026] The vulcanizing apparatus 100 preferably includes a lifting mechanism 6 that moves the central mechanism 4 up and down (raises and lowers). The lifting mechanism 6 includes a lifting drive unit 61 and a lifting transmission unit 62 that transmits the output of the lifting drive unit 61 to the central mechanism 4. The lifting drive unit 61 is, for example, a hydraulic cylinder or an air cylinder and is fixed to the lower part of the container 2. In Figure 1, only one lifting drive unit 61 is shown, but in reality, multiple lifting drive units 61 are provided. The lifting transmission unit 62 is, for example, a lifting plate that is raised and lowered by the lifting drive unit 61 and rotatably supports the center post 41. Note that the lifting mechanism 6 is not limited to the above.

[0027] The vulcanizing apparatus 100 preferably includes an air blowing device (not shown) capable of blowing air onto the vulcanizing mold 1. An air supply pipe for supplying pressurized air is connected to the air blowing device.

[0028] [Method for cleaning tire vulcanization molds] Next, the method for cleaning the tire vulcanization mold 1 will be explained with reference to Figures 2 to 4. Figure 2 is a flow chart showing the method for cleaning the tire vulcanization mold 1. Figure 3 shows the rotation process ST2. Figure 4 shows the tire removal process ST3. In Figures 3 and 4, the ventilation holes 17 (see Figure 1) provided in the vulcanization mold 1 are not shown.

[0029] First, as shown in Figures 2 and 3, after vulcanization molding, at least one mold 10 is separated to a cleaning position X1 (separation step ST1). That is, in separation step ST1, at least one of the tread mold 11, upper side mold 12, and lower side mold 13 is separated to a cleaning position X1. The cleaning position X1 is the position where the outer surface of the tire T is separated from the tire molding surface 16 and the spew SP formed on the tire T comes into contact with the tire molding surface 16.

[0030] The separation distance G2 from the outer surface of the tire T to the tire molding surface 16 at the cleaning position X1 is preferably 5 mm or more and 15 mm or less. In this embodiment, the separation distance G2 is, for example, 10 mm. The length of the spew SP can be adjusted by the vulcanization temperature and vulcanization time, etc.

[0031] At the cleaning position X1, it is preferable that the protrusions (for example, protrusions forming the main grooves) provided on the tire molding surface 16 of the tread mold 11 are at least 2 mm away from the outer surface of the tire T in the tire radial direction D2. This is to avoid contact between the tire T and its protrusions during the rotation process ST2 described later.

[0032] In the separation step ST1 of this embodiment, the tread mold 11 and the upper side mold 12 are separated to the cleaning position X1. Specifically, the upper side mold 12 is separated upward, and the tread mold 11 is separated outward in the tire radial direction D2. However, this is not limited to this, and for example, one of the tread mold 11 and the upper side mold 12 may be separated to the cleaning position X1, and the other may be separated to a position further from the outer surface of the tire T than the cleaning position X1 (for example, the tire mounting / detachment position X2 shown in Figure 4). Alternatively, at least the tread mold 11 may be separated to the cleaning position X1.

[0033] In this embodiment, the aforementioned displacement amount G1 is provided. As a result, when the tread mold 11 and the upper side mold 12 separate, the tire T, which was pressed against the upper side mold 12, returns to its original position (away from the lower side mold 13) (restores itself). As a result, the tire T can be separated from the lower side mold 13 without moving the central mechanism 4 after vulcanization molding. However, this is not the only option; for example, the central mechanism 4 may be raised to separate the tire T from the lower side mold 13. The displacement amount G1 is appropriately set according to the length of the spew SP formed on the tire T.

[0034] Next, the tire T held by the bladder 3 is rotated in the circumferential direction of the tire (rotation process ST2). As a result, the spew SP formed on the tire T rotates while in contact with the tire molding surface 16 (the spew SP sweeps the tire molding surface 16), allowing the spew SP to remove (sweep away) dirt (residue such as spew separated from the tire T) attached to the tire molding surface 16. As a result, the accumulation of residue in the mold 10 can be suppressed, and the maintenance interval of the vulcanization mold 1 can be extended (for example, from every 2000 tires to every 4000 tires). In addition, as the spew SP rotates while in contact with the tire molding surface 16, for example, the spew SP can come into contact with and entangle rubber burrs formed on the mating surfaces of the tread mold 11 and the side molds 12, 13 or the mating surfaces of the sectors, thereby removing those rubber burrs.

[0035] In the rotation process ST2, it is preferable that the number of rotations of the tire T is 5 or more. This enhances the cleaning effect of the tire molding surface 16 by the spew SP. The rotation time of the tire T is preferably 30 seconds or more. This ensures the cleaning effect of the tire molding surface 16. Furthermore, it is preferable that the rotation time of the tire T is 60 seconds or less. This suppresses delays in the vulcanization molding process due to cleaning of the tire molding surface 16 and prevents deterioration of the productivity of the tire T.

[0036] In the rotation process ST2, it is preferable to rotate the tire T while moving it up and down using the lifting mechanism 6. From the viewpoint of enhancing the cleaning effect of the tire molding surface 16, it is preferable that the vertical movement of the tire T is 5 mm or more on each side. From the viewpoint of enhancing the cleaning effect of the tire molding surface 16, it is preferable that the vertical movement of the tire T is continuous. However, the vertical movement of the tire T may be, for example, intermittent.

[0037] Next, as shown in Figures 2 and 4, the tread mold 11 and the upper side mold 12 are separated to the tire mounting / detachment position X2, and the tire T is removed (tire removal process ST3). The tire mounting / detachment position X2 is the position where the unvulcanized tire is mounted and the tire T after vulcanization is removed. It is preferable to discharge the vulcanizing medium filled inside the bladder 3 when separating the tread mold 11 and the upper side mold 12 to the tire mounting / detachment position X2. However, the discharge of the vulcanizing medium may be performed after separating the tread mold 11 and the upper side mold 12 to the tire mounting / detachment position X2.

[0038] Finally, after removing the tire T from the vulcanization mold 1 (tire removal step ST3), it is preferable to blow air onto at least the tire molding surface 16 of the lower side mold 13 using an air blowing device (air blowing step ST4). In the air blowing step ST4, it is more preferable to blow air onto the lower platen 24. This blows away any residue that has fallen onto the lower platen 24 and prevents residue from accumulating on the lower platen 24. In the air blowing step ST4, air may also be blown onto the tire molding surface 16 of the tread mold 11 and the upper side mold 12.

[0039] [1] The method for cleaning the tire vulcanization mold 1 includes a separation step ST1 in which, after the vulcanization molding of the tire T, at least one mold 10 is separated to a cleaning position X1 in which the outer surface of the tire T is separated from the tire molding surface 16 and the spew SP formed on the tire T is in contact with the tire molding surface 16, and a rotation step ST2 in which the tire T held by the bladder 3 is rotated in the circumferential direction of the tire.

[0040] According to this method, the spew SP rotates while in contact with the tire molding surface 16, allowing the spew SP to remove dirt (residue) from the tire molding surface 16. This makes it possible to clean the tire vulcanization mold 1 without installing a new cleaning device.

[0041] [2] In the cleaning method for the tire vulcanization mold 1 according to the above embodiment [1], a preferred method is to rotate the tire T while moving it up and down in the rotation process ST2.

[0042] According to this method, the cleaning range of the tire molding surface 16 can be increased by rotating the spew SP while moving it up and down. This enhances the cleaning effect of the vulcanization mold 1. On the tire molding surface 16 of the tread mold 11, the cleaning range of the tire molding surface 16 is increased as the spew SP moves up and down relative to the tire molding surface 16. On the tire molding surfaces 16 of the side molds 12 and 13, the cleaning range of the tire molding surface 16 is increased as the spew SP approaches the tire molding surface 16 due to the up and down movement, increasing the contact range between the spew SP and the tire molding surface 16.

[0043] [3] A preferred method for cleaning the tire vulcanization mold 1 according to the above embodiment [1] or [2] is one in which, after removing the tire T from the tire vulcanization mold 1, an air blowing step ST4 is performed in which air is blown onto at least the tire molding surface 16 of the lower side mold 13.

[0044] According to this method, residue remaining on the tire molding surface 16 of the lower side mold 13 can be removed by air. This enhances the cleaning effect of the tire molding surface 16.

[0045] Furthermore, the cleaning method for the tire vulcanization mold 1 is not limited to the configuration and method of the embodiment described above, nor is it limited to the effects described above. In addition, the tire vulcanization mold 1 can be modified in various ways without departing from the spirit of the present invention. [Explanation of Symbols]

[0046] 100…Vulcanizing apparatus, 1…Tire vulcanizing mold, 10…Mold, 11…Tread mold, 12…Upper side mold, 13…Lower side mold, 14, 15…Bead ring, 16…Tire molding surface, 17…Ventilation hole, 2…Container, 21…Segment, 22…Outer ring, 23…Upper platen, 24…Lower platen, 25…Arm, 26…Guide, 3…Tire vulcanizing bladder, 4…Central mechanism, 41… Center post, 42... Upper clamp, 43... Lower clamp, 44... Cylindrical section, 5... Rotation mechanism, 51... Rotation drive unit, 52... Rotation transmission unit, 521... First gear, 522... Second gear, 6... Lifting mechanism, 61... Lifting drive unit, 62... Lifting transmission unit, SP... Spew, ST1... Separation process, ST2... Rotation process, ST3... Tire removal process, ST4... Air blowing process, T... Tire, X1... Cleaning position, X2... Tire attachment / detachment position

Claims

1. After the vulcanization molding of the tire, a separation step is made to separate at least one mold to a cleaning position in which the outer surface of the tire separates from the tire molding surface and the spew formed on the tire comes into contact with the tire molding surface. The process includes a rotation step of rotating the tire held by the bladder in the circumferential direction of the tire, A method for cleaning a tire vulcanization mold, wherein the rotation step involves rotating the tire while moving it up and down.

2. A method for cleaning a tire vulcanization mold according to claim 1, further comprising an air blowing step of blowing air onto the tire molding surface of at least the lower side mold after removing the tire from the tire vulcanization mold.

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