JP4234578B2 - Tire vulcanization mold - Google Patents

Description

  The present invention relates to a sectional type tire vulcanization mold having a plurality of sectors. More specifically, the division position of the sector is optimized with respect to the formed bone of the inclined groove, and the formed bone of the inclined groove is appropriately used. The present invention relates to a mold for tire vulcanization molding that prevents the generation of burrs in a vulcanized tire by processing into a vulcanized tire.

  Sectional type tire vulcanization molds are usually a pair of side plates that mold the sidewalls, a pair of bead rings that mold the beads, and a plurality of treads and shoulders that are integrally molded. And the sector. The materials used in these sectors are mainly aluminum alloys that are excellent in castability and machinability, and have high thermal conductivity and good vulcanization efficiency. In addition, when rubber vulcanizes, rubber enters into the minute gaps between sectors, and in particular, burrs are likely to occur at the groove bottom of the vulcanized tire, but in order to avoid such burrs, In general, grooves extending in the tire profile cross-sectional direction are not applied to the division positions between sectors except for the grooves in the tire circumferential direction (see, for example, Patent Document 1).

On the other hand, in recent years, the tread design of tires has been diversified, and the number of inclined grooves extending in an oblique direction with respect to the tire circumferential direction has increased. Therefore, it becomes increasingly difficult to select a division position between sectors while avoiding such inclined grooves. Due to the tread design restrictions, burrs are likely to occur when the inclined position is divided between sectors.
Japanese Patent Laid-Open No. 5-24044

  An object of the present invention is to prevent the occurrence of burrs in a vulcanized tire by optimizing the sector dividing position with respect to the formed bone of the inclined groove and appropriately processing the formed bone of the inclined groove. The object is to provide a mold for vulcanization molding.

  The tire vulcanization molding die of the present invention for solving the above object is a tire vulcanization molding die having a plurality of sectors for integrally molding a tread portion and both shoulder portions of a pneumatic tire. When dividing a pair of adjacent sectors at a position on a formed bone of an inclined groove extending in the tire profile cross-sectional direction, the formed bone of the inclined groove forms an angle of 30 ° or more with respect to the tire profile cross-sectional direction, and The division position of the sector is set so that the divided position section of the formed bone of the inclined groove and the divided position section of the formed bone of the main groove extending in the tire circumferential direction adjacent to the inclined groove are continuous, and the inclined groove The height h of the smaller divided piece of the two divided pieces of the formed bone satisfies the relationship of h ≦ 0.8 × D with respect to the depth D of the main groove, and the smaller Dividing pieces in the tire circumferential direction The tip of the small divided piece is deleted so as to satisfy the relationship of h ≦ 5 × A with respect to the width A.

  In the present invention, in a tire vulcanization mold having a plurality of sectors made of aluminum alloy, when a pair of adjacent sectors is divided at a position on the forming groove of the inclined groove extending in the tire profile cross-sectional direction, the inclined groove is provided. The formed bone is formed at an angle of 30 ° or more with respect to the tire profile cross-sectional direction, and the divided position cross section of the formed groove of the inclined groove and the divided bone of the main groove extending in the tire circumferential direction adjacent to the inclined groove The division position of the sector is set so that the position cross section is continuous, and the height h of the small divided piece of the formed bone of the inclined groove has a specific relationship with the depth D of the main groove and the width A of the small divided piece. Delete the tip of the small segment so that As a result, even when the sector division position is set to a position that hangs on the inclined groove, the rubber is prevented from being pinched between the divided pieces of the formed bone of the inclined groove, and the occurrence of burrs in the vulcanized tire is prevented. can do.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to expand the design freedom at the time of selecting the division | segmentation position of a sector about the tread design containing an inclination groove | channel. In addition, since the distal end side of the small divided piece constituting the forming bone of the inclined groove is deleted, there is an advantage that the small divided piece can be prevented from being damaged and the maintenance work of the mold can be reduced.

  In the present invention, when the width A of the small divided pieces is less than 1 mm, the small divided pieces may be deleted up to the tread surface position. On the other hand, when the width A of the small divided piece is 1 mm or more, only the distal end side of the small divided piece is deleted and the proximal end side remains. It is preferable to chamfer the remaining portion of such small pieces.

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

  FIG. 1 shows a tire vulcanization molding die according to an embodiment of the present invention, and FIGS. As shown in FIG. 1, the tire vulcanization mold according to this embodiment includes a pair of side plates 1 and 2 that form a sidewall portion of the pneumatic tire T, and a pair of bead rings 3 that form a bead portion. , 4 and a plurality of sectors 5 for integrally forming a tread portion and both shoulder portions. These sectors 5 are annularly arranged around the tread portion of the pneumatic tire T.

  FIG. 2 shows a pair of adjacent sectors 5 </ b> A and 5 </ b> B among the plurality of sectors 5. A tread molding surface 51 of a plurality of sectors 5 including these sectors 5A and 5B has a main groove forming bone 52 for forming a main groove extending in the tire circumferential direction, and an inclination extending in the tire profile cross-sectional direction (tire width direction). An inclined groove forming bone 53 for forming the groove is formed.

  As shown in FIG. 2, when the pair of adjacent sectors 5A and 5B is divided at the position where the inclined groove forming bone 53 is engaged, the inclined groove forming bone 53 forms an angle α of 30 ° or more with respect to the tire profile cross-sectional direction. In addition, the division position X of the sectors 5A and 5B is set so that the division position cross section of the inclined groove forming bone 53 and the division position cross section of the main groove forming bone 52 are continuous. That is, the division position X that continuously crosses the main groove forming bone 52 and the inclined groove forming bone 53 having an angle α of 30 ° or more is selected. Here, the upper limit of the angle α is 50 °. As a result, the inclined groove forming bone 53 is divided into two in the tire circumferential direction at the division position X, and a large divided piece 53L belonging to one of the sectors 5A and 5B and a small divided piece 53S belonging to one of the sectors 5A and 5B, Become. The small divided pieces 53S protrude from the side wall of the main groove forming bone 52.

  FIG. 3 shows a cross section taken along the line Y-Y in FIG. In FIG. 3, when the height of the small divided piece 53S is h, the depth of the main groove (the height of the main groove formed bone) is D, and the width in the tire circumferential direction of the small divided piece 53S is A, the small The height h of the divided piece 53S satisfies the relationship of h ≦ 0.8 × D and h ≦ 5 × A. In order to satisfy the above relationship, a portion (broken line portion) on the tip side of the small divided piece 53S is deleted.

  As described above, when the adjacent pair of sectors 5A and 5B is divided at the position where the inclined grooves are engaged, the division position X of the sectors 5A and 5B is optimized, and the height of the small divided pieces 53S of the inclined groove forming bone 53 is increased. The tip side of the small segment 53S is deleted so that h satisfies a specific relationship with the depth D of the main groove and the width A of the small segment 53S. As a result, even when the division position X of the sectors 5A and 5B is set to a position where the sector 5A and 5B is engaged with the inclined groove, the rubber is prevented from being caught between the divided pieces 53L and 53S of the inclined groove forming bone 53 and vulcanized. Generation | occurrence | production of the burr | flash in a tire can be prevented.

  Here, when the angle α formed by the inclined groove forming bone 53 with respect to the tire profile cross-sectional direction is less than 30 °, the rigidity at the end of the small divided piece 53S becomes insufficient, and at the time of tire vulcanization molding or die The small divided pieces 53S are likely to be deformed or broken during opening and closing. Further, when 0.8 × D <h ≦ D, burrs are likely to occur. Further, in the case of 5 × A <h, deformation or breakage of the small segment 53S is likely to occur during tire vulcanization molding or when the mold is opened and closed.

  The width A of the small divided piece 53S can be appropriately set within the range satisfying the above conditions. However, when 0 mm <A <1 mm, the deformation of the small divided piece 53S is performed at the time of tire vulcanization molding or when the mold is opened and closed. And damage is likely to occur. Therefore, when 0 mm <A <1 mm, the small segment 53S may be deleted up to the tread surface position (h = 0 mm). In this case, a part of the inclined groove disappears at the tread surface position, but since the width A of the small divided piece 53S is very small, it is not particularly noticeable in appearance.

  On the other hand, when 1 mm ≦ A, only the distal end side of the small divided piece 53S is deleted and the proximal end side remains. It is preferable to chamfer the remaining portion of the small segment 53S. In particular, the chamfering process may be performed on a portion excluding the contact surface of the small divided piece 53S with the large divided piece 53L. This makes it difficult for rubber to enter between the split pieces 53L and 53S of the inclined groove forming bone 53.

  In the embodiment described above, a pair of adjacent sectors 5A and 5B are extracted and described with respect to these sectors 5A and 5B. Of course, in the present invention, the division positions of all sectors 5 can be selected based on the above relationship. It is.

  Production of tire vulcanization molds of Examples 1 to 4 and Comparative Examples 1 to 6 in which only the division position of the sector is varied in a sectional type tire vulcanization mold having a plurality of sectors. did. At this time, the angle α formed by the inclined groove forming bone at the sector division position with the tire profile cross-sectional direction, the height h of the small divided piece of the inclined groove forming bone, and the width A of the small divided piece are as shown in Table 1. By setting, the division position of the sector was selected. The depth D of the main groove was 12 mm.

Using these tire vulcanization molds of Examples 1 to 4 and Comparative Examples 1 to 6, vulcanization molding of pneumatic tires was repeatedly performed. Then, at the time when 100 vulcanization moldings were performed on each tire vulcanization molding die, whether or not burrs were generated in the vulcanized tire, and whether or not the small-divided pieces of the inclined groove molding bone in the mold were damaged Examined. The results are also shown in Table 1.

  As can be seen from Table 1, in the tire vulcanization molds of Examples 1 to 4, no burrs were generated in the vulcanized tire, and the small divided pieces of the inclined groove-formed bone were not damaged. On the other hand, in Comparative Examples 1-6, the burr | flash generate | occur | produced or the inconvenience that the small division | segmentation piece of the sloping groove formation bone | frame was damaged occurred.

It is sectional drawing which shows the metal mold | die for tire vulcanization molding which consists of embodiment of this invention. FIG. 2 is a plan view showing a pair of adjacent sectors from the tread molding surface side in the tire vulcanization molding die of FIG. 1. It is a YY arrow sectional drawing of FIG.

Explanation of symbols

1, 2 Side plate 3, 4 Bead ring 5, 5A, 5B Sector 51 Tread forming surface 52 Main groove forming bone 53 Inclined groove forming bone 53L Large segment 53S Small segment h Height of small segment A A Small segment Width D Depth of main groove (height of main groove forming bone)
T Pneumatic tire X Split position

Claims (3)

In a tire vulcanization mold having a plurality of sectors for integrally forming a tread portion and both shoulder portions of a pneumatic tire, a pair of adjacent sectors are hung on a forming groove of an inclined groove extending in a tire profile cross-sectional direction. When dividing at the position, the formed bone of the inclined groove forms an angle of 30 ° or more with respect to the tire profile cross-sectional direction, and the tire circumferential position is adjacent to the divided position cross section of the formed groove of the inclined groove and the inclined groove. The division position of the sector is set so that the sectional position of the forming bone of the main groove extending in the direction is continuous, and the small divided piece having the smaller volume of the two divided pieces of the forming bone of the inclined groove The height h satisfies the relationship of h ≦ 0.8 × D with respect to the depth D of the main groove, and the relationship of h ≦ 5 × A with respect to the width A in the tire circumferential direction of the small segment. To satisfy the small divided pieces Tire mold for vulcanization molding deleting the distal end side. The tire vulcanization molding die according to claim 1, wherein a width A of the small divided pieces is less than 1 mm, and the small divided pieces are deleted up to a tread surface position. The tire vulcanization mold according to claim 1, wherein a chamfering process is performed on a remaining portion of the small divided piece.

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