JP5994553B2 - Tire vulcanization mold and method for manufacturing pneumatic tire - Google Patents

Description

  The present invention relates to a tire vulcanization mold and a method for manufacturing a pneumatic tire. More specifically, the present invention relates to a method for manufacturing a tire and a pneumatic tire. The present invention relates to a tire vulcanization mold having excellent properties and a method for producing a pneumatic tire using the tire vulcanization mold.

  The tire vulcanization mold is provided with an exhaust mechanism that discharges air remaining between the green tire and the mold and gas generated during vulcanization to the outside of the mold. Conventionally, various exhaust mechanisms for preventing spewing have been proposed (see, for example, Patent Documents 1 to 3).

  In the invention described in Patent Document 1, when a piece constituting a mold is cast, the molten metal is shot in a plurality of times. In the cast piece, a minute gap due to solidification shrinkage of the molten metal is formed at a joint portion between shots, and this minute gap becomes an exhaust passage. However, when such a cast mold is subjected to shot blast cleaning, a fine gap is crushed by the spray material to be sprayed, so that there is a possibility that sufficient exhaust cannot be secured. Therefore, for example, plasma cleaning has been used for cleaning such a cast mold. However, plasma cleaning has problems that equipment and processing cost are higher than that of shot blast cleaning, processing time is long, and maintenance is inferior.

  In the invention described in Patent Document 2, a die rib is projected from and fitted to a circumferential groove formed on a tire molding surface of a sector. And the minute gap used as an exhaust path is formed under the overhang | projection part of a die rib between a tire molding surface. By forming a minute gap under the overhanging portion of the die rib, it is difficult for rubber to enter during vulcanization. However, if the die rib is made of the same aluminum as the mold, the problem that the minute gaps are crushed when the mold is shot blast cleaned cannot be solved. Further, since the die rib is a projection that forms a circumferential groove in the green tire, there is a problem that it cannot be easily removed.

  Patent Document 3 proposes an exhaust mechanism using a laminated blade in which a thin plate is bent to overlap one end and a large gap is secured to the other end in order to ensure sufficient exhaust. The laminated blade is held by a block, and an exhaust chamber surrounded by the pocket and the block is formed by fitting the block into a concave pocket on the molding surface of the mold. Air or gas is discharged into the exhaust chamber through a minute gap at one end of the laminated blade and a large gap at the other end. However, in this exhaust mechanism, in order to remove the laminated blade, first, it is necessary to remove the block fitted in the pocket. For this reason, it takes time to replace damaged laminated blades or periodically replace laminated blades. Along with this, there is a problem that maintenance cannot be easily performed with the laminated blade removed.

JP 2000-229322 A Special table 2010-528904 JP 2008-260135 A

  An object of the present invention is to make a tire vulcanization mold that is open to a tire molding surface and hardly crushes a minute gap functioning as an exhaust passage to ensure sufficient exhaust and maintainability, and the tire vulcanization mold It is providing the manufacturing method of the pneumatic tire using this.

In order to achieve the above object, a tire vulcanization mold according to the present invention is a tire vulcanization mold having a plurality of sectors assembled in an annular shape, and extends from one end to the other end in the circumferential direction of the sector. A liner embedded groove formed on a surface, and a strip-shaped liner that is harder than the base material of the sector and is detachably embedded in the liner embedded groove, and the liner embedded groove and the liner embedded groove A minute gap is formed between the liner and the liner, and the minute gap communicates with an exhaust hole communicating with the outside of the sector, and the liner is buried under a lateral groove forming protrusion on the tire molding surface or It is the state which penetrated the horizontal groove formation protrusion .

  The method for producing a pneumatic tire according to the present invention is characterized in that a green tire is vulcanized using the tire vulcanization mold described above.

  According to the tire vulcanization mold of the present invention, the liner embedded groove formed on the tire molding surface of the sector extending from one end to the other end in the circumferential direction of the sector, and harder than the base material of the sector, A strip-shaped liner that is detachably embedded in the liner embedded groove, and a minute gap is formed between the liner embedded groove and the liner embedded in the liner embedded groove. Although it does not pass, it can function as an exhaust passage through which air or gas passes. Then, air or gas can be discharged to the outside of the sector through the exhaust hole communicating with the minute gap.

  Since the liner serving as the wall surface forming the minute gap is harder than the base material of the sector, the minute gap is not easily crushed even when the sector is shot blast cleaned. Therefore, it is advantageous for securing sufficient exhaust gas and the maintainability is improved. In addition, since the liner is strip-shaped, it is easy to embed in the shape of the bottom of the arc-shaped tire molding surface, and it is easy to replace the liner or perform maintenance with the liner removed. Also has excellent maintainability.

  Here, it can also be set as the specification in which the said liner embedding groove | channel is formed in the side surface root part of the circumferential direction groove | channel formation protrusion of the said tire molding surface. According to this specification, a minute gap serving as an exhaust passage is formed at a position where unnecessary air and gas are likely to accumulate during vulcanization of the green tire, which is advantageous in preventing vulcanization failure.

  The base part that is harder than the base material of the sector, extends from one end to the other end in the circumferential direction of the sector, is exposed to the tire molding surface and is detachably incorporated into the base material of the sector constitutes a part of the tire molding surface And it can also be set as the specification by which the said liner embedding groove | channel is formed in this base part. According to this specification, since both wall surfaces forming the minute gap are harder than the base material of the sector, the minute gap is less likely to be crushed.

  The liner and the base portion may be made of the same material. According to this specification, unnecessary deformation due to thermal expansion can be made difficult to occur between the liner and the base portion.

  According to the method for manufacturing a pneumatic tire of the present invention, since the sector can be shot blast cleaned, it is possible to reduce the mold maintenance cost and the maintenance time. These contribute to the improvement of tire production efficiency.

It is a side view which illustrates the mold for tire vulcanization of the present invention. It is a top view which illustrates the sector of FIG. FIG. 3 is a front view illustrating the left half of the sector in FIG. 2. FIG. 4 is a partially enlarged view of the sector of FIG. 3. It is explanatory drawing which illustrates the state which attaches / detaches the liner of FIG. 3 to a liner embedding groove | channel by planar view. It is a top view which illustrates the left half of the sector of another embodiment of the present invention. FIG. 7 is a partially enlarged front view of the sector of FIG. 6. It is explanatory drawing which illustrates the state which attaches and detaches the liner of FIG. 6 to a liner embedding groove | channel by planar view. It is explanatory drawing which illustrates the state which attaches and detaches the base part of FIG. 6 to the base material of a sector by planar view.

  Hereinafter, a tire vulcanization mold of the present invention and a method for manufacturing a pneumatic tire using the tire vulcanization mold will be described based on the embodiments shown in the drawings. C arrow, R arrow, and W arrow described in the drawings indicate a circumferential direction, a radial direction, and a width direction of a green tire that is inserted into a vulcanization mold and vulcanized.

  As illustrated in FIGS. 1 to 4, a tire vulcanization mold 1 (hereinafter referred to as a mold 1) according to the present invention is a sectional type including a plurality of sectors 2 assembled in an annular shape. A back block 4 is attached to the back surface of the sector 2. The inner peripheral surface of the sector 2 becomes the tire molding surface 5. The base material of sector 2 is a metal material such as aluminum or aluminum alloy, and sector 2 is cast using such a metal material.

  On the tire molding surface 5, a circumferential groove forming projection 6 a for forming a circumferential groove and a lateral groove forming projection 6 b for forming a lateral groove are formed integrally with the base material of the sector 2. . The number, arrangement, and shape of the circumferential groove forming protrusions 6a and the lateral groove forming protrusions 6b are determined by the specifications of the pneumatic tire to be manufactured.

  A liner embedding groove 3 extending from one end in the circumferential direction of the sector 2 to the other end is formed on the tire molding surface 5. Further, it has a belt-like liner 7 that is harder than the base material of the sector 2 and is detachably embedded in the liner-embedding groove 3. The liner 7 is embedded in almost the entire length of the liner embedding groove 3.

  In this embodiment, the liner burying groove 3 is formed on the side surface root portion of the circumferential groove forming protrusion 6a and the bottom surface 5a of the tire molding surface 5 (the portion that becomes the tread surface of the pneumatic tire). The liner embedded groove 3 is open to the tire molding surface 5. At the position of the lateral groove forming protrusion 6 b, the liner embedded groove 3 is a through hole that passes under the lateral groove forming protrusion 6 b or a through hole that passes through the lateral groove forming protrusion 6 b. It has become. Accordingly, the liner 7 embedded in the liner embedded groove 3 is embedded under the horizontal groove forming protrusion 6b or penetrated into the horizontal groove forming protrusion 6b.

  The exposed surface of the liner 7 embedded in the liner embedded groove 3 formed on the bottom surface 5 a of the tire molding surface 5 is at the same level as the bottom surface 5 a of the tire molding surface 5. The exposed surface of the liner 7 embedded in the liner embedded groove 3 formed at the side surface root portion of the circumferential groove forming protrusion 6a is at the same level as the side surface of the circumferential groove forming protrusion 6a.

  The material of the liner 7 is a hard material such as general carbon steel, stainless steel, or iron. The thickness t of the liner 7 is, for example, about 1 mm to 5 mm. When the thickness t of the liner 7 is excessively large, it becomes difficult to bend along the arc of the bottom surface 5a of the tire molding surface 5, and when the thickness t is excessively small, handling properties such as embedding and removing from the liner embedded groove 3 are deteriorated. . The width w of the liner 7 is, for example, about 1 mm to 10 mm.

  A minute gap 8 is formed between the liner buried groove 3 and the liner 7 buried in the liner buried groove 3. The minute gap 8 communicates with an exhaust hole 9 that communicates with the outside of the sector 2. The exhaust hole 9 of this embodiment extends in the circumferential direction of the sector 2 and opens at both end surfaces in the circumferential direction of the sector 2. However, the present invention is not limited to this, and for example, extends in the thickness direction of the sector 2 and opens at the back surface. The exhaust hole 9 may be used. An end face plate 11 is attached to the circumferential end face of the sector 2 so as to cover the opening of the liner buried groove 3. The end face plate 11 can be optionally provided.

  Since the minute gap 8 becomes an exhaust passage, the size thereof is about 0.01 mm to 0.08 mm, and more preferably 0.02 mm to 0.08 mm in order to prevent spewing while ensuring sufficient exhaust. 03 mm. In the drawing, the minute gap 8 is exaggerated and enlarged. In this embodiment, the minute gaps 8 are formed on both sides of the liner 7 in the width direction or both sides in the thickness direction, but the minute gaps 8 are formed only on one side in the width direction or only on one side in the thickness direction. You can also.

  As illustrated in FIG. 5, the liner 7 can be easily embedded by being pushed into the liner embedding groove 3 from one end side in the circumferential direction of the sector 2 toward the other end side. When removing the liner 7 embedded in the liner embedding groove 3, after removing the end face plate 11, the liner 7 is pushed in from the circumferential direction one end side to the other end side of the sector 2 and slightly from the other end face of the sector 2. Make it protrude. Next, the liner 7 can be easily pulled out and removed from the liner embedding groove 3 by grasping and pulling the other end of the liner 7 that has been projected.

  Since the liner 7 on one side of the wall surface forming the minute gap 8 is harder than the base material of the sector 2, it is difficult to be deformed even if the projection material is sprayed after the sector 2 is shot blast cleaned. That is, the minute gap 8 is not easily crushed. Therefore, sufficient exhaust can be ensured through the minute gap 8 even after shot blast cleaning.

  Along with this, since shot blast cleaning can be used instead of plasma cleaning for cleaning of sector 2, the cost of cleaning equipment and cleaning processing can be suppressed, and the processing time can be shortened. Yes.

  Since the liner 7 has a belt shape, it is easy to embed the liner 7 in the liner embedding groove 3 in a shape along the bottom surface 5a of the tire molding surface 5 that is arcuate in side view. Therefore, replacement when the liner 7 is damaged and periodic replacement work are simplified, and maintenance can be easily performed with the liner 7 removed, which is also excellent in maintainability.

  When the green tire is vulcanized using the mold 1 assembled with the sector 2, unnecessary air and gas are discharged to the exhaust hole 9 through the minute gap 8, and further discharged to the outside of the mold 1 through the end face of the sector 2, etc. The In this way, it is possible to ensure appropriate exhaust during vulcanization, so that tire vulcanization failure can be effectively prevented.

  Further, according to this method for manufacturing a pneumatic tire, the sector 2 can be shot blast cleaned, so that the maintenance cost of the mold 1 can be reduced and the maintenance time can be shortened. These contribute to the improvement of tire production efficiency.

  The place where the liner burying groove 3 (the minute gap 8) is provided is a position where air and gas easily accumulate during vulcanization. The positions where air and gas are likely to accumulate are the base portions of the circumferential groove forming projections 6a and the lateral groove forming projections 6b. Therefore, as in this embodiment, the liner embedded grooves 3 (micro gaps 8) are provided in these portions and the vicinity thereof. Is preferred.

  Further, the liner 7 is in a state of being embedded under the horizontal groove forming protrusion 6b or penetrating into the horizontal groove forming protrusion 6b at the position of the horizontal groove forming protrusion 6b. Therefore, the liner 7 does not move to the inner peripheral side of the sector 2 and leave the sector 2. Therefore, after the green tire is vulcanized, when the mold 1 is opened by moving the sector 2 in the outer circumferential direction, the liner 7 adheres to the vulcanized pneumatic tire and is detached from the liner buried groove 3. Is prevented.

  In another embodiment of the mold 1 illustrated in FIGS. 6 and 7, a part of the tire molding surface 5 is a base portion 10 that is detachably incorporated into the base material of the sector 2. The base portion 10 is harder than the base material of the sector 2, extends from one end to the other end in the circumferential direction of the sector 2, and is exposed on the tire molding surface 5. The base portion 10 extends from one end to the other end in the circumferential direction of the sector 2 and is incorporated in a fitting groove 10 a formed on the tire molding surface 5. The material of the base portion 10 is a hard material such as general carbon steel, stainless steel, or iron.

  A liner buried groove 3 is formed in the base portion 10. A liner 7 is embedded in the liner embedded groove 3 as in the previous embodiment. A minute gap 8 is formed between the liner 7 and the base portion 10. The minute gap 8 communicates with an exhaust hole 9 that leads to the outside of the sector 2. In this embodiment, since both wall surfaces constituting the minute gap 8 are hard materials (the liner 7 and the base portion 10), the minute gap 8 becomes more difficult to be crushed.

  The method of attaching / detaching the liner 7 to / from the liner burying groove 3 is the same as in the previous embodiment. Therefore, as illustrated in FIG. 8, the liner 7 can be easily removed while the base portion 10 is incorporated in the tire molding surface 5. Further, as illustrated in FIG. 9, the base unit 10 can be periodically removed from the base material of the sector 2 for maintenance although the frequency is low.

  The liner 7 and the base portion 10 can be made of different materials, but are preferably made of the same material. By using the same material, it becomes easy to prevent a problem in which unnecessary deformation due to thermal expansion occurs when both are heated between the liner 7 and the base portion 10.

  The present invention is not limited to the above-described embodiment, and can be applied to a mold 1 in which a plurality of pieces (divided bodies of sectors 2) are arranged in close contact to form a sector 2.

DESCRIPTION OF SYMBOLS 1 Mold 2 Sector 3 Liner embedding groove 4 Back block 5 Tire shaping | molding surface 5a Bottom face 6a Circumferential groove shaping | molding protrusion 6b Lateral groove formation protrusion 7 Liner 8 Minute clearance 9 Exhaust hole 10 Base part 10a Fitting groove 11 End surface plate

Claims (5)

In a tire vulcanization mold having a plurality of sectors assembled in an annular shape, a liner embedded groove formed on a tire molding surface of the sector extending from one end to the other end in the circumferential direction of the sector, and a base material of the sector Is also hard and has a strip-like liner that is detachably embedded in the liner-embedded groove, and a minute gap is formed between the liner-embedded groove and the liner embedded in the liner-embedded groove. The gap communicates with an exhaust hole that communicates with the outside of the sector, and the liner is embedded under or penetrates the lateral groove forming protrusion on the tire molding surface. Mold for tire vulcanization.   The tire vulcanization mold according to claim 1, wherein the liner burying groove is formed at a side surface root portion of a circumferential groove forming protrusion of the tire molding surface.   The base part that is harder than the base material of the sector, extends from one end to the other end in the circumferential direction of the sector, is exposed to the tire molding surface and is detachably incorporated into the base material of the sector constitutes a part of the tire molding surface The tire vulcanization mold according to claim 1, wherein the liner buried groove is formed in the base portion.   The tire vulcanization mold according to claim 3, wherein the liner and the base portion are formed of the same material.   The manufacturing method of the pneumatic tire which vulcanizes a green tire using the mold for tire vulcanization in any one of Claims 1-4.

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