JP4899609B2 - Tire mold and method for manufacturing pneumatic tire using the tire mold - Google Patents

Description

  The present invention relates to a tire molding die and a method for manufacturing a pneumatic tire using the tire molding die, and more specifically, suppresses a mold release failure at the time of tire vulcanization release and suppresses deformation of a block. The present invention relates to a tire molding die capable of suppressing uneven wear and improving the edge effect of a block, and a method for manufacturing a pneumatic tire using the tire molding die.

  Conventionally, a tire molding die for a pneumatic tire has been provided with a siping blade for forming a narrow groove that is continuously folded in the depth direction from the surface of the tire tread surface. It is known that unevenness is provided to prevent the block from deforming greatly during braking and driving of the tire by friction between the wall surfaces, improving the edge effect of the block and suppressing uneven wear. (For example, refer to Patent Document 1).

However, when a tire is vulcanized with such a conventional molding die having a siping blade, the resistance from the tire molding die increases at the time of tire vulcanization and release, resulting in a vulcanization failure (separation). There is a problem that mold defects are likely to occur.
JP 2003-182314 A

  The present invention pays attention to such conventional problems, and is caused by defective mold release by maintaining the effect of suppressing deformation during braking and driving of the tire while not increasing the resistance at the time of mold release. An object of the present invention is to provide a tire molding die capable of preventing vulcanization failure and a method for manufacturing a pneumatic tire using the tire molding die.

  In order to achieve the above-mentioned object, the tire molding die according to the present invention has a friction that is greater than a surface of a continuous folded surface of a siping blade that faces inward in the tire radial direction and faces outward in the tire radial direction. The gist is that it is formed on a rough surface with increased force.

  Here, a rough surface having a large frictional force is formed on the entire surface or a part of the surface facing the inner side in the tire radial direction, and the rough surface is a straight uneven portion, a rhombic uneven portion, At least one selected from a satin-like uneven portion and a dimple-like uneven portion is used. Moreover, it is preferable that the uneven | corrugated | grooved part height of the said rough surface is 1 to 30% of the thickness of a siping blade.

  Further, a method for manufacturing a pneumatic tire using the tire molding die of the present invention includes disposing an unvulcanized tire in a tire molding die provided with the above-described siping blade, and forming the tire molding die. The gist of the invention is to manufacture a pneumatic tire by closing and closing and heating and pressurizing the unvulcanized tire to form a vulcanized product.

  Here, at the time of vulcanization molding of the unvulcanized tire, a narrow groove that is turned back in the depth direction is formed on the tire tread portion by the siping blade of claim 1, and the tire diameter of the narrow groove is A rough surface in which the frictional force is larger than the surface facing the outer side in the tire radial direction is formed on the inner surface in the direction.

  By adopting such a configuration, vulcanization failure due to mold release failure can be achieved by maintaining the effect of suppressing deformation during braking and driving of the tire while not increasing the resistance at the time of mold release. Can be prevented beforehand.

Since the present invention is configured as described above, the following excellent effects can be obtained. (a) Demolding failure during vulcanization demolding of the tire can be suppressed.
(b) Since deformation of the tire block can be suppressed, uneven wear can be suppressed and the edge effect of the block can be improved.
(c) When the shape of the siping blade is formed in a press die, it is transferred at the time of press molding, so that it can be easily manufactured and the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a partially enlarged plan view of a tire tread surface portion of a pneumatic tire molded by a tire molding die according to an embodiment of the present invention, and FIG. 2 shows a plurality of siping blades provided in the tire molding die. A perspective view is shown, and in this embodiment, the above-mentioned siping blade 1 forms a narrow groove (sipe) 3 that is continuously folded back from the surface of the tire tread surface 2 in the depth direction.

  According to the embodiment of the present invention, the vulcanization failure due to the mold release failure can be prevented by not increasing the resistance at the time of mold release while maintaining the effect of suppressing deformation during braking and driving of the tire. 3 (a), (b) to FIG. 6 (a) to (d), among the continuous folded surfaces 1a, 1b of the siping blade 1, the inner side in the tire radial direction The surface 1b facing the surface is formed on the rough surface 4 having a larger frictional force than the surface 1a facing the outer side in the tire radial direction.

  As a concrete embodiment of the rough surface 4, for example, as shown in FIGS. 3A and 3B and FIGS. 4A and 4B, a surface 1 b facing inward in the tire radial direction, Horizontal or vertical straight irregularities 4a or 4b, rhomboid irregularities 4c as shown in FIGS. 5A and 5B, and straight as shown in FIG. 5C. The uneven portion 4b and the rhombic uneven portion 4c can be combined. Further, as other embodiments of the rough surface 4, as shown in FIGS. 6A to 6D, oblique line-shaped uneven parts 4d, rhombus 4e, satin-like uneven parts 4f, dimple-shaped uneven parts The part 4g or the like can be considered, and one or more of these uneven parts can be combined or formed on the entire surface or a part of the surface 1a facing inward.

  The height of the uneven portion is preferably 1 to 30% of the thickness t of the siping blade 1, more preferably 0.05 mm to the distance S between the trough and the top. 1.0 mm is preferred. Note that when the thickness t of the siping blade 1 is set to 1% or more, the mold releasability is improved, and when the thickness t is set to 30% or less, a decrease in strength of the siping blade 1 can be suppressed. In addition, the surface roughness of the rough surface 4 is preferably Rmax 5 μm to 300 μm when the textured uneven portion 4 f is used.

  8 to 10 show the relationship between the siping blade 1 provided on the mold 5 during tire vulcanization and the tire W, FIG. 8 shows the state before vulcanization release, and FIG. 9 shows the start of vulcanization release. As shown in FIG. 10, the siping blade 1 according to this embodiment has a smooth surface 1a facing outward in the tire radial direction and friction with a surface 1b facing inward of the tire radial direction. By forming on the rough surface 4 having an uneven shape with a large force, the resistance at the time of mold release is small, and defective mold release can be prevented.

  The block of the tire W in which the narrow groove (sipe) is formed by the siping blade 1 as described above can suppress deformation during braking and driving of the tire.

  In addition, as a method for manufacturing the siping blade 1 as described above, for example, a flat metal plate before press bending is subjected to bending after providing intermittent unevenness in advance, or a press bending die is previously set. If the irregularities are crafted, the irregularities can be transferred at the same time as the bending process.

  FIGS. 11 to 15 show another embodiment of the siping blade 1. In this embodiment, a narrow groove (sipe) is formed by the bending siping blade 1x in the tire tread portion 2 of the pneumatic tire. It is a thing.

  That is, in this embodiment, the continuous folding surface 1a of the siping blade 1x is also provided in the siping blade 1x that forms a corrugated narrow groove (sipe) in the plane of the tire tread portion 2 as in the above embodiment. 1b, the surface 1b facing inward in the tire radial direction forms a rough surface 4a having a larger frictional force than the surface 1a facing out in the tire radial direction. Mold defects can be prevented. Further, the block of the tire W in which the wavy narrow groove (sipe) is formed by the siping blade 1x can suppress deformation during braking and driving of the tire.

  When a pneumatic tire is manufactured using a tire molding die provided with the siping blade 1 as described above, an unvulcanized tire is placed in the tire molding die, and the vulcanized tire is vulcanized. At the time of molding, a narrow groove 3 that is turned back in the depth direction is formed on the tire tread surface portion 2 by the siping blade 1 as described above, and a surface of the narrow groove 3 facing inward in the tire radial direction is formed. A rough surface having a larger frictional force than a surface facing outward in the tire radial direction is formed.

  Thereby, the block of the manufactured pneumatic tire can suppress deformation at the time of braking and driving of the tire.

  Next, the evaluation experiment result of the tire molding die provided with the siping blade 1 as described above and the pneumatic tire manufactured thereby will be described.

This evaluation method is performed in units of blocks, and the dimensions and specifications of the siping blade and the tire block are as follows.
(1). Dimensions of siping blades Total height: 7mm, sipe width: 30mm, wave amplitude: 1.5mm, wave pitch: 2mm (2). Tire block dimensions Height: 10mm, width: 30mm, Depth: 30m, Hardness: JIS A Hardness 55 (JIS K6253) As a comparison method, the corrugated shape of the siping blade is the same as the straight straight unevenness, the location of the unevenness applied to the siping blade, and the surface roughness It was evaluated by the difference combination.

  As shown in FIGS. 16A to 16C, the evaluation of the releasability of the siping blade is performed based on the magnitude of the resistance when the siping blade 1 provided on the mold is pulled out from the rubber block R. The block rigidity is evaluated by the amount of deformation when the base G provided with the siping blade 1 is pressed with a constant force. The value is expressed as an index with the conventional example being 100, and the larger the value, the better. The evaluation results are shown in Table 1. Each of the results is represented by an index, and the larger the number, the better.

1 is a partially enlarged plan view of a tire tread portion of a pneumatic tire molded by a tire molding die according to an embodiment of the present invention. It is a perspective view of a plurality of siping blades provided in a tire molding die. (A) is the perspective view formed in the rough surface which increased frictional force in the surface which faces the inner side of a tire radial direction among the continuous folding surfaces of a siping blade, (b) is the AA arrow of (a). FIG. (A) is the perspective view formed in the rough surface which made the frictional force large in the surface which faces the inner side of a tire radial direction among the continuous folding surfaces of a siping blade, (b) is BB arrow of (a). FIG. (A)-(c) is a perspective view of other embodiment formed in the rough surface which increased frictional force in the surface which faces the inner side of a tire radial direction among the continuous folding surfaces of a siping blade. . (A)-(d) is explanatory drawing of each embodiment of the pattern of the rough surface formed in the surface which faces the inner side of a tire radial direction. It is explanatory drawing of the corrugated uneven | corrugated | grooved part of a siping blade. It is an expanded sectional view showing the relation between a siping blade provided in a mold at the time of tire vulcanization and a tire, and showing a state before vulcanization release. FIG. 3 is an enlarged cross-sectional view showing a relationship between a sipe blade provided on a mold during tire vulcanization and a tire, and showing a state immediately after the start of vulcanization release. The relationship between the tire and the siping blade provided on the mold during vulcanization of the tire is shown, the surface facing the outer side in the tire radial direction is formed smoothly and the surface facing the inner side in the tire radial direction is partially formed It is an expanded sectional view. FIG. 5 is an enlarged plan view showing another embodiment of a siping blade, in which a narrow groove (sipe) is formed by a bending siping blade in a tire tread portion of a pneumatic tire. It is the partially expanded view in which the corrugated narrow groove (sipe) was formed in the plane of a tire tread part. It is a partially expanded sectional view in which a corrugated narrow groove (sipe) is formed in a tire tread surface portion. (A) is CC sectional view taken on the line of FIG. 13, (b) is DD sectional view taken on the line of FIG. It is the perspective view which formed the corrugated narrow groove (sipe) in the tire tread part. (A)-(d) is explanatory drawing which shows the evaluation experiment of the tire molding die provided with the siping blade, and the pneumatic tire manufactured by it.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Siping blade 1a, 1b Folding surface 2 Tire tread surface 3 Narrow groove (sipe)
4 Rough surface
4a, 4b, 4c, 4d Uneven portion 4e Rhombus 4f, 4g Uneven portion 5 Mold S Distance t Thickness W Tire

Claims (5)

In a mold for molding a tire provided with a siping blade for forming a narrow groove that is continuously folded in the depth direction from the surface of the tire tread surface,
Of the continuous folded surfaces of the siping blade, a tire molding metal is characterized in that a surface facing inward in the tire radial direction is formed into a rough surface having a larger frictional force than a surface facing outward in the tire radial direction. Type.   2. The tire molding die according to claim 1, wherein a rough surface having a large frictional force is formed on the entire surface or a part of the surface facing the inner side in the tire radial direction.   3. The tire molding according to claim 1, wherein the rough surface uses at least one selected from a straight uneven portion, a rhombus-like uneven portion, a satin-like uneven portion, and a dimple-like uneven portion. Mold.   4. The tire molding die according to claim 1, wherein a height of the uneven portion of the rough surface is 1 to 30% of a thickness of the siping blade.   An unvulcanized tire is disposed in a tire molding die provided with the siping blade according to any one of claims 1 to 4, and the tire molding die is closed to heat the unvulcanized tire. , A method for producing a pneumatic tire using a tire molding die for producing a pneumatic tire by pressurizing and vulcanizing.

Images