JP2006305891A - Method for producing pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a pneumatic tire which can suppress the occurrence of a failure caused by a defective rubber flow during vulcanization even when a projection such as a rim protection bar is formed in a tire side part. <P>SOLUTION: A carcass member 1 is wound onto a molding drum, at a position corresponding to the tire side part on the peripheral side of the carcass member 1, in addition to a belt-shaped side rubber extruded object 2 of an unvulcanized rubber, a strip material 3 of the unvulcanized rubber whose width is narrower than the width of the side rubber extruded object 2 is wound, and a primary green tire 10 including the carcass member 1, the side rubber extruded object 2, and the strip material 3 is molded. The primary green tire 10 is expanded in a toroidal shape, and annular belt members 11 are stuck together at a position corresponding to a tire tread part to mold a secondary green tire 20. The secondary green tire 20 is vulcanized in a mold 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a pneumatic tire suitable for a case where a protrusion such as a rim protect bar is provided on a tire side portion, and more specifically, it is possible to suppress the occurrence of a failure due to a rubber flow failure during vulcanization. The present invention relates to a method for manufacturing a pneumatic tire.

  In a pneumatic tire, a projecting portion is provided on a tire side portion for the purpose of improving the appearance and functionality. For example, a rim protect bar may be provided on the tire side portion for the purpose of protecting the rim flange (see, for example, Patent Document 1). In addition, for the purpose of improving the appearance, characters such as brand names may protrude from the tire surface. The effect of these protrusions increases as the protrusion amount and the dimension in the tire radial direction increase.

  On the other hand, when producing a pneumatic radial tire, a carcass member is wound on a forming drum, and a belt-like side rubber made of an unvulcanized rubber extrudate at a position corresponding to the tire side portion on the outer peripheral side of the carcass member The member is wound to form a primary green tire including the carcass member and the side rubber member. Then, the primary green tire is inflated into a toroidal shape, and an annular belt member is bonded to a position corresponding to the tire tread portion to form a secondary green tire, and the secondary green tire is vulcanized in a mold. Yes.

However, when the above-mentioned protrusion is provided on the tire side portion, a recess corresponding to the protrusion is formed on the inner surface of the mold, but rubber does not sufficiently flow into the recess during vulcanization, resulting in a vulcanization failure. May occur.
Japanese Patent Laid-Open No. 11-78441

  An object of the present invention is to manufacture a pneumatic tire that can suppress the occurrence of a failure due to poor rubber flow during vulcanization even when a protrusion such as a rim protect bar is provided on a tire side portion. It is to provide a method.

  In order to achieve the above object, a method for producing a pneumatic tire according to the present invention comprises winding a carcass member on a forming drum and placing the unvulcanized rubber at a position corresponding to the tire side portion on the outer peripheral side of the carcass member. In addition to the strip-shaped side rubber extrudate, a strip material made of unvulcanized rubber and having a narrower width than the side rubber extrudate is wound, and a primary green tire including the carcass member, the side rubber extrudate, and the strip material. The primary green tire is inflated into a toroidal shape, and an annular belt member is bonded to a position corresponding to the tire tread portion to form a secondary green tire, and the secondary green tire is added in a mold. It is characterized by being sulfurized.

  In the present invention, since the tire side portion is composed of the side rubber extrudate made of unvulcanized rubber and the laminate of the strip material, the volume of the tire side portion can be adjusted based on the laminated state of the strip material. Therefore, even when a protrusion such as a rim protect bar is provided on the tire side portion, it is possible to suppress the occurrence of a failure due to defective rubber flow during vulcanization.

  As the side rubber extrudate, for example, one having a substantially uniform thickness excluding both end portions in the width direction can be commonly used for various profiles. When a flat side rubber extrudate is employed, when the side rubber extrudate is transported in a wound state, it is less likely to collapse and the collapse due to its own weight can be reduced. On the other hand, the size, position, and shape of the protrusions can be arbitrarily set based on the lamination state of the strip material. The size of the strip material is not particularly limited. For example, it is desirable to use a strip material having a thickness of 1 to 2 mm and a width of 5 to 15 mm.

  When manufacturing a pneumatic tire having a rim protect bar protruding from the tire surface on the tire side portion, a laminate of strip materials may be disposed at the position of the rim protect bar. In this case, it is preferable that the width of the laminate of the strip material constituting the rim protect bar is 10 to 50% of the tire cross-sectional height and 50 to 150% of the width of the rim protect bar. Thereby, productivity and a vulcanization failure suppression effect can be made compatible. Further, the JIS-A hardness at 25 ° C. of the strip material constituting the rim protect bar is preferably higher by 10 to 50 points than the JIS-A hardness at 25 ° C. of the side rubber extrudate. Thereby, the protection effect of a rim flange can be improved.

  The side rubber extrudate and the strip material can be composed of materials having different rubber properties after vulcanization. That is, various rubber materials can be used in combination according to the purpose. Similarly, at least two types of strip materials made of materials having different rubber properties after vulcanization may be prepared, and these at least two types of strip materials may be arranged at different positions in the tire radial direction.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 illustrates a primary green tire in the method for producing a pneumatic tire of the present invention. In the present invention, first, as shown in FIG. 1, a carcass member 1 is wound around a molding drum (not shown), and an unvulcanized rubber is provided at a position corresponding to the tire side portion on the outer peripheral side of the carcass member 1. In addition to the strip-shaped side rubber extrudate 2 made of the above, a strip material 3 having a narrower width than the side rubber extrudate 2 and made of unvulcanized rubber is wound, and the carcass member 1, the side rubber extrudate 2 and the strip material 3 are wound. The primary green tire 10 containing is molded. FIG. 1 shows a state in which the strip material 3 is wound around one tire side portion, but the strip material 3 is also wound around the other tire side portion. Of course, in addition to the carcass member 1, the side rubber extrudate 2, and the strip material 3, the primary green tire 10 appropriately includes tire constituent members such as an inner liner member 4, a bead core 5, a bead filler 6, and a reinforcing member 7. (See FIG. 3).

  FIG. 2 shows the laminated state of the side rubber member and the strip material in the primary green tire in the method for manufacturing a pneumatic tire of the present invention together with the mold profile. As shown in FIG. 2, the side rubber extrudate 2 has a width extending over the entire region of the tire side portion, and has a substantially uniform thickness except for both end portions in the width direction. Although the thickness of the side rubber extrudate 2 is not specifically limited, For example, it can be set to 1-5 mm. The side rubber extrudate 2 is obtained by cutting a single gauge extrudate made of unvulcanized rubber to a desired width. On the other hand, the strip material 3 has a thickness of 1 to 2 mm and a width of 5 to 15 mm, for example, and is laminated according to the profile of the mold 30. That is, the rubber necessary for the tire side portion is satisfied by the side rubber extrudate 2 for one turn of the tire and the laminate of the strip material 3 wound a plurality of times in the tire circumferential direction.

  FIG. 3 illustrates a secondary green tire obtained from the primary green tire of FIG. After forming the primary green tire, as shown in FIG. 3, the primary green tire is inflated into a toroidal shape, and an annular belt member 11 is bonded to a position corresponding to the tire tread portion to form the secondary green tire 20. Mold. Of course, the secondary green tire 20 may appropriately include a tire constituent member such as the belt cover member 12 and the tread rubber extrudate 13 in addition to the belt member 11. The secondary green tire 20 thus obtained is vulcanized in the mold 30.

  According to the method for manufacturing a pneumatic tire described above, the tire side portion is constituted by the laminated body of the side rubber extrudate 2 made of unvulcanized rubber and the strip material 3, so that the tire side is based on the laminated state of the strip material 3. The volume of the part can be adjusted. Therefore, even when a protrusion such as a rim protect bar is provided on the tire side portion, it is possible to suppress the occurrence of a failure due to defective rubber flow during vulcanization.

  As the side rubber extrudate 2, for example, a material having a substantially uniform thickness except for both end portions in the width direction can be prepared and used in common for various profiles. When the flat side rubber extrudate 2 is employed, when the side rubber extrudate 2 is transported in a wound state, it is difficult to cause collapse and the collapse due to its own weight can be reduced. Furthermore, while making the side rubber extrudate 2 common, the size, position, and shape of the protrusion can be arbitrarily set based on the lamination state of the strip material 3.

  In addition, by using the side rubber extrudate 2 and the strip material 3 in combination, an effect of preventing the secondary green tire 20 from being deformed can be obtained. That is, in the case where the tire side portion is constituted only by the strip material 3, it is difficult to maintain the integrity of the laminate of the strip material 3 when the primary green tire 10 is deformed into a toroidal shape. The presence of the object 2 can ensure the integrity of the laminate of the strip material 3 and give the secondary green tire 20 good quality.

  4 and 5 show other laminated states of the side rubber member and the strip material in the primary green tire in the method for producing a pneumatic tire of the present invention, respectively. In FIG. 4, the side rubber extrudate 2 is wound on the carcass member 1, and the strip material 3 is wound on only a part of the tire side portion on the side rubber extrudate 2. In FIG. 5, the strip material 3 is wound around only a part of the tire side portion on the carcass member 1, and the side rubber extrudate 2 is wound on the carcass member 1 so as to cover the laminate of the strip material 3. . Thus, the winding order of the side rubber extrudate 2 and the strip material 3 is not particularly limited.

  FIG. 6 shows another laminated state of the side rubber member and the strip material together with the mold profile in the primary green tire in the method for manufacturing a pneumatic tire of the present invention. As shown in FIG. 6, the side rubber extrudate 2 has a width extending over the entire region of the tire side portion, but the strip material 3 has a thickness of 1 to 2 mm and a width of 5 to 15 mm, for example. It is laminated only at the position of the rim protect bar. That is, the recess 30 for forming the rim protect bar is formed in the mold 30, but a laminate of the strip material 3 is formed in accordance with the recess 31.

  Thus, if the laminated body of the strip material 3 is arranged at the position of the rim protect bar, the strip material 3 can compensate for the insufficient volume of the rim protect bar. Therefore, even when a rim protect bar protruding from the tire surface is provided on the tire side portion, it is possible to suppress the occurrence of a failure due to a poor rubber flow during vulcanization. Moreover, since it is not necessary to partly adjust the side rubber extrudate 2 with the rim protect bar, the side rubber extrudate 2 is less likely to collapse when transported in a wound state, and is not crushed by its own weight. Can be relaxed.

  In this case, it is preferable that the width L2 of the laminate of the strip members 3 constituting the rim protect bar is 10 to 50% of the tire cross-sectional height and 50 to 150% of the width L1 of the rim protect bar. However, the width L2 of the laminate of the strip members 3 is a width measured in the tire axial direction on the forming drum, and the width L1 of the rim protect bar is a width of the recess corresponding to the rim protect bar in the mold. By setting the width L2 within the above range, both productivity and the effect of suppressing vulcanization failure can be achieved. Here, if the width L2 is too wide, the productivity is lowered, and conversely if it is too narrow, the effect of suppressing the vulcanization failure is lowered.

  Further, the JIS-A hardness at 25 ° C. of the strip material 3 constituting the rim protect bar is preferably 10 to 50 points higher than the JIS-A hardness of the side rubber extrudate 2 at 25 ° C. Thereby, the protection effect of a rim flange can be improved. Here, if the hardness of the strip material 3 constituting the rim protect bar is increased too much and the difference exceeds 50 points, the portion corresponding to the side rubber extrudate 2 on the tire side portion and the portion corresponding to the strip material 3 A difference in deformation amount at the time of bending becomes large, and a failure such as separation or rubber chipping is likely to occur. A more preferable range of the hardness difference between them is 25 to 40 points.

  About the side rubber extrudate 2 and the strip material 3, not only hardness but the rubber physical property after vulcanization can be comprised from a mutually different material. In this case, various rubber materials can be used in combination according to the purpose. For example, the appearance can be improved by increasing the amount of wax in the side rubber extrudate 2 embedded in the tire and decreasing the amount of wax in the strip material 3 exposed to the outside of the tire.

  FIG. 7 shows another laminated state of the side rubber member and the strip material in the primary green tire in the method for manufacturing a pneumatic tire of the present invention. As shown in FIG. 7, the side rubber extrudate 2 has a width extending over the entire region of the tire side portion, but the strip material 3 has a thickness of 1 to 2 mm and a width of 5 to 15 mm, for example. The rubber is laminated on the side rubber extrudate 2 so as to form a desired profile in the tire side portion.

  Here, as the strip material 3, a plurality of types of strip materials 3A, 3B, 3C, 3D made of materials having different rubber properties after vulcanization are used. These strip materials 3A to 3D are arranged at different positions in the tire radial direction. More specifically, the strip material 3A constitutes a gum finishing near the bead core, the strip material 3B constitutes a rim cushion near the rim flange, the strip material 3C constitutes a rim protection bar, and the strip material 3D constitutes a side tread. Is configured. In FIG. 7, the boundary between the gum finishing, the rim cushion, the rim protection bar, and the side tread is represented by the difference in hatching. The blending of the strip materials 3A to 3D is not particularly limited, but a rubber composition suitable for each part may be selected.

  FIG. 8 illustrates a secondary green tire obtained from the primary green tire of FIG. After forming the primary green tire, as shown in FIG. 3, the primary green tire is inflated into a toroidal shape, and an annular belt member 11 is bonded to a position corresponding to the tire tread portion to form a secondary green tire 20. To do. Of course, the secondary green tire 20 may appropriately include a tire constituent member such as the belt cover member 12 and the tread rubber extrudate 13 in addition to the belt member 11. The secondary green tire 20 thus obtained is vulcanized in the mold 30.

  As described above, the side rubber extrudate 2 is disposed on the tire side portion, and a plurality of types of strip materials 3A to 3D made of materials having different rubber properties after vulcanization are prepared. In addition to being able to suppress the occurrence of failures due to poor rubber flow during vulcanization, even when protrusions such as rim protect bars are provided on the tire side by arranging them at different positions in the direction. As a result, steering stability and ride comfort can be improved.

FIG. 9 shows a modification of FIG. In FIG. 9, a plurality of types of strip materials are used according to the position in the tire radial direction as in FIG. 7, but the side tread is composed of two types of strip materials 3D ₁ and 3D ₂ . . When the formation region of the side tread is expressed on a 100% scale, the JIS-A hardness at 25 ° C. is 59 or more and the tan δ at 60 ° C. is 30 to 70% from the outer end in the tire radial direction. A strip material 3D _{1 of} 0.17 or more is arranged, and in a region from the inner end in the tire radial direction to a position of 30 to 70%, the JIS-A hardness at 25 ° C. is 53 or less and the tan δ at 60 ° C. is 0. .14 or less strip material 3D ₂ is arranged.

By defining the physical properties of the strip materials 3D ₁ and 3D ₂ constituting the side tread in this way, it is possible to adjust the synthetic balance of the tire side portions and achieve both higher handling stability and riding comfort at a higher level. .

  1000 pneumatic tires having a tire size of 235 / 35R18 and equipped with a rim protect bar on the side of the tire were manufactured by the method of the conventional example and the example, respectively, and there was a failure due to a poor rubber flow near the rim protect bar. The appearance was determined and the vulcanization failure rate was determined. The dimensions of the rim protect bar were set so that the amount of protrusion of the rim protect bar from the rim flange when the pneumatic tire was assembled to an 18 × 8 JJ rim was at least 8 mm.

  In the embodiment, a carcass member is wound on a molding drum, and in addition to the belt-shaped side rubber extrudate made of unvulcanized rubber, the side rubber extrusion is provided at a position corresponding to the tire side portion on the outer peripheral side of the carcass member. A strip material made of unvulcanized rubber having a width smaller than that of the product is wound, a primary green tire including the carcass member, the side rubber extrudate, and the strip material is formed, and the primary green tire is expanded into a toroidal shape. Then, an annular belt member was bonded to a position corresponding to the tire tread portion to form a secondary green tire, and the secondary green tire was vulcanized in a mold. Here, the laminated body of strip materials was disposed only at the position of the rim protect bar (FIG. 6). In the conventional example, a pneumatic tire was manufactured under the same conditions as in the example except that only the side rubber extrudate was used without forming the strip material for forming the tire side portion.

  As a result, the vulcanization failure occurrence rate in the conventional example was 10.5%, whereas the vulcanization failure occurrence rate in the example of the present invention was only 0.5%. Moreover, in the Example of this invention, since the side rubber extrudate was made substantially flat, when conveying a side rubber extrudate in the state wound up, neither collapse nor collapse by self-weight occurred.

It is a perspective view which illustrates the primary green tire in the manufacturing method of the pneumatic tire of the present invention. It is sectional drawing which shows the lamination | stacking state of the side rubber member and strip material in the primary green tire in the manufacturing method of the pneumatic tire of this invention with a metal mold | die profile. It is sectional drawing which shows the principal part of the secondary green tire obtained from the primary green tire of FIG. It is sectional drawing which shows the other laminated state of the side rubber member and strip material in the primary green tire in the manufacturing method of the pneumatic tire of this invention. It is sectional drawing which shows the other laminated state of the side rubber member and strip material in the primary green tire in the manufacturing method of the pneumatic tire of this invention. It is sectional drawing which shows the other lamination | stacking state of the side rubber member and strip material in a primary green tire in the manufacturing method of the pneumatic tire of this invention with a mold profile. It is sectional drawing which shows the other laminated state of the side rubber member and strip material in the primary green tire in the manufacturing method of the pneumatic tire of this invention. It is sectional drawing which shows the principal part of the secondary green tire obtained from the primary green tire of FIG. It is sectional drawing which shows the modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carcass member 2 Side rubber extrudate 3 Strip material 4 Inner liner member 5 Bead core 6 Bead filler 7 Reinforcement member 10 Primary green tire 11 Belt member 12 Belt cover member 13 Tread rubber extrudate 20 Secondary green tire 30 Mold 31 Recess

Claims (8)

  A carcass member is wound on a molding drum, and is narrower than the side rubber extrudate in addition to the belt-like side rubber extrudate made of unvulcanized rubber at a position corresponding to the tire side portion on the outer peripheral side of the carcass member. A strip material made of unvulcanized rubber and having a width is wound around to form a primary green tire including the carcass member, the side rubber extrudate, and the strip material, and the primary green tire is inflated into a toroidal shape to form a tire tread portion. A method for producing a pneumatic tire, comprising: forming a secondary green tire by bonding an annular belt member at a position corresponding to the above, and vulcanizing the secondary green tire in a mold.   The method for manufacturing a pneumatic tire according to claim 1, wherein the side rubber extrudate has a substantially uniform thickness except for both end portions in the width direction.   The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein the strip material has a thickness of 1 to 2 mm and a width of 5 to 15 mm.   In the manufacturing method of the pneumatic tire provided with the rim protection bar which protrudes from the tire surface in a tire side part, the layered product of the above-mentioned strip material is arranged in the position of the above-mentioned rim protection bar. A method of manufacturing a pneumatic tire.   5. The pneumatic tire according to claim 4, wherein a width of the laminate of the strip members constituting the rim protect bar is 10 to 50% of a tire cross-sectional height and 50 to 150% of a width of the rim protect bar. Manufacturing method.   The JIS-A hardness at 25 ° C of the strip material constituting the rim protection bar is 10 to 50 points higher than the JIS-A hardness at 25 ° C of the side rubber extrudate. Method of manufacturing a pneumatic tire.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein the side rubber extrudate and the strip material are made of materials having different rubber properties after vulcanization. The at least 2 types of strip material which consists of a material from which the rubber | gum physical property after vulcanization mutually differs is prepared, These at least 2 types of strip materials are arrange | positioned in the mutually different position of a tire radial direction. Method of manufacturing a pneumatic tire.

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