JP2011031522A - Tire vulcanizing mold and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate balancing between the generation of crown bares and the tire appearance by reducing variations in gap between adjacent pieces. <P>SOLUTION: A tire vulcanizing mold is configured as follows. A plurality of pieces 14 are arranged side by side in one sector 12. A plurality of the sectors 12 are circularly arranged. Each gap 16 for removing air in-between a raw tire during tire vulcanization is discontinuously arranged between the adjacent pieces 14. The range of the gap 16 is narrowed as compared with that when continuously providing each gap 16 between the pieces 14 over the whole length in the tire-width direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire vulcanization mold and a pneumatic tire.

  A so-called split mold type tire vulcanization mold is disclosed which is composed of two or more segments and each segment has two or more pieces (see Patent Document 1).

JP 2002-361632 A

  Generally, on the tread surface of a pneumatic tire for a small passenger car, when vulcanizing with a vulcanization mold, the air between the raw tire and the mold is extracted from the spew hole provided in the vulcanization mold. Spew is formed. However, in recent years, high-grade and sport-type pneumatic tires are required to improve appearance and initial performance, and therefore, Supurees that prevents spewing during vulcanization has become mainstream.

  Therefore, a tire vulcanization mold in which a plurality of pieces are arranged in one sector and the plurality of sectors are arranged in a circle is used. When manufacturing this vulcanization mold, a certain distance is ensured in the entire range of the gap between adjacent pieces.

  However, when a large number of tires are vulcanized using such a mold, the rubber gradually becomes clogged between adjacent pieces, and if the vulcanization is continued as it is, the air between the green tire and the mold cannot be removed. Will occur. Therefore, it is necessary to disassemble the mold in a short period and clean the end face of the piece before the crown bear is generated.

  Further, if there is a variation in the size of the gap between the pieces as viewed from the entire mold, a bear may be generated at the initial stage of vulcanization in the tire crown near the narrow space. If the end face of the piece is cleaned, the bear will not be generated temporarily. However, since the bear reoccurs immediately, it is necessary to clean it in a short cycle. Since this cleaning takes time, there is a secondary problem of increased man-hours.

  When a crown bear occurs in the initial stage of vulcanization, the present situation is that the center value of the size of the gap is raised and corrected with variation in the size of the gap between pieces. However, since the rubber protrusion height on the tire side increases and the appearance deteriorates, it is necessary to correct while verifying the balance between the occurrence of crown bears (piece cleaning cycle) and the appearance of the tire.

  In view of the above facts, the present invention has an object to reduce the variation in the gap between adjacent pieces so as to easily balance the occurrence of crown bear and the appearance of a tire. To do.

  The invention of claim 1 (tire vulcanization mold) is a tire vulcanization mold configured by arranging a plurality of pieces in one sector and arranging the plurality of sectors in a circular shape. A gap for removing air from the raw tire during vulcanization is provided discontinuously between the adjacent pieces.

  In the tire vulcanization mold according to claim 1, the gap between adjacent pieces is discontinuous, and the range in which the gap is provided is narrowed. Thereby, the dispersion | variation in the clearance gap between adjacent pieces can be made small. In addition, by setting an appropriate gap between pieces located in a portion where a crown bear is likely to occur, the occurrence of the crown bear can be prevented and deterioration in appearance can be suppressed.

  Here, the lower limit of the size of the gap is set to 0 because the gap is set to 0 in a portion where the gap is not necessary. Moreover, the reason why the upper limit of the size of the gap is set to 70 μm is that when the gap is exceeded, the appearance is deteriorated.

  A second aspect of the present invention is the tire vulcanization mold according to the first aspect, wherein the size of the gap is 0 to 70 μm.

  In the tire vulcanization mold according to claim 2, since the size of the gap is 0 to 70 μm, the size of the protruding portion of the rubber formed on the tire surface corresponding to the gap between the pieces is minimized. While suppressing, generation | occurrence | production of a crown bear can be suppressed.

  According to a third aspect of the present invention, in the tire vulcanization mold according to the first or second aspect, the piece is provided with a bone portion for forming a circumferential main groove, and the size of the gap is large. The height is set to be 0 at the position of the bone part.

  In the tire vulcanization mold according to claim 3, the piece is provided with a bone portion for forming a circumferential main groove, and the size of the gap between adjacent pieces is determined by the position of the bone portion. Since it is set to be 0, a circumferential main groove continuous in the tire circumferential direction can be formed in the tread portion. In addition, since there is a gap between the pieces corresponding to only the position where the crown bear is easily noticeable in the tread portion, when cleaning the piece to which the rubber is attached, it is necessary to clean only the area of the gap. Well, work becomes easy.

  According to a fourth aspect of the present invention, in the tire vulcanization mold according to the third aspect, the bone part of at least one of the adjacent pieces extends from the end surface of the piece in the tire circumferential direction to the bone part of the other piece. Projecting toward each other, and the bone portions of each other are in contact with each other.

  In the tire vulcanization mold according to the fourth aspect, by simply combining the pieces, adjacent bone portions come into contact with each other, and a gap between portions other than the bone portions is accurately set. Thereby, the dispersion | variation in the clearance gap between adjacent pieces can be made small easily.

  The invention (pneumatic tire) of claim 5 is vulcanized and molded using the tire vulcanization mold according to any one of claims 1 to 4.

  Since the pneumatic tire according to claim 5 is vulcanized using the tire vulcanization mold according to any one of claims 1 to 4, generation of crown bear is suppressed. At the same time, the appearance is improved.

  As described above, according to the tire vulcanizing mold according to the first aspect of the present invention, an excellent effect of being able to be obtained is obtained.

  According to the tire vulcanization mold according to claim 2, it is possible to suppress the occurrence of crown bear while minimizing the protruding portion of the rubber formed on the tire surface corresponding to the gap between the pieces. The excellent effect of being able to be obtained is obtained.

  According to the tire vulcanization mold according to the third aspect, an excellent effect of facilitating the piece cleaning operation can be obtained.

  According to the tire vulcanization mold according to the fourth aspect of the present invention, it is possible to obtain an excellent effect that the variation in the gap between adjacent pieces can be easily reduced.

  According to the pneumatic tire of the fifth aspect, it is possible to obtain an excellent effect that the generation of crown bear is suppressed and the appearance is improved.

It is a front view which shows the mold for tire vulcanization seen from the tire axial direction. It is a partial fracture perspective view showing the sector holding a plurality of pieces. It is an expansion perspective view which shows a piece. It is a front view showing the state where two pieces were arranged side by side in the tire circumferential direction. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. 1 and 2, the tire vulcanization mold 10 according to the present embodiment is configured by arranging a plurality of pieces 14 side by side in one sector 12 and arranging the plurality of sectors 12 in a circular shape. It is a so-called inserter segment type tire vulcanization mold, and a gap 16 is formed between adjacent pieces 14 for removing air from a raw tire (not shown) when the tire is vulcanized. It has been. The sector 12 is provided with a recess 12A corresponding to the shape of the piece 14 so that a plurality of pieces 14 can be held side by side in the recess 12A.

  The piece 14 is a member that defines the shape of the outer surface of the tire 20, for example, the shape of the tread portion 18 (FIG. 5) and the shoulder portion 22 (FIG. 5). In FIG. 3, the piece 14 is provided with a general portion 24 for forming the outer surface of the tread portion 18 and the shoulder portion 22 and a bone portion 28 for forming the circumferential main groove 26 (FIG. 5). Yes. The bone portion 28 is configured as, for example, a convex portion extending in the tire circumferential direction, and at least one end 30 protrudes from the end surface 32 of the general portion 24 on the one end 30 side by a predetermined amount. Although both end portions 34 of the piece 14 in the tire width direction are not directly related to the definition of the outer surface shape of the tire 20, one end 35 of each end portion 34 protrudes in the same manner as one end 30 of the bone portion 28. On the other hand, as shown in FIG. 4, the other end 36 of the bone portion 28 and the other end 37 of both end portions 34 are both flush with the end surface 38 on the other end 36 side of the general portion 24.

  As shown in FIG. 3, the end surface 32 of the piece 14 is formed with a groove 40 serving as an intake path when air is released through the gap 16 (FIG. 4). The groove portion 40 extends, for example, in the tire width direction and opens at both ends of the piece 14. In addition, the shape of the groove part 40 is not restricted to the thing of illustration. Further, the groove portion 40 may be provided on the end surface 38 of the piece 14 or may be provided on both the end surfaces 32 and 38.

  As shown in FIG. 4, when two pieces 14 having the same shape are arranged in the same direction in the tire circumferential direction, one end 30 of the bone portion 28 in one piece 14 is connected to one end 30 of the bone portion 28 in the other piece 14. While being in contact with the other end 36, one end 35 of both end portions 34 of one piece 14 is in contact with the other end 37 of both end portions 34 of the other piece 14. In other words, the bone portions 28 and the end portions 34 of the adjacent pieces 14 are in contact with each other. Accordingly, the gap 16 is zero at the position of the bone portion 28 and the both end portions 34.

However, since one end 30 of the bone portion 28 and the other end 37 of the one end 35 protrude from the end surface 32 of one piece 14 by a predetermined amount, the end surface 32 of one piece 14 and the end surface 38 of the other piece 14 are It will be in the state separated without contacting each other.

  That is, the gap 16 between the adjacent pieces 14 is interrupted at the positions of both end portions 34 and the bone portion 28 of the piece 14 in the tire width direction, and between the both end portions 34 and the bone portion 28 and between the adjacent bone portions 28. Since it is formed only in between, it becomes discontinuous.

  The size W of the gap 16 is 0 to 70 μm. Here, the reason why the lower limit of the size W of the gap 16 is set to 0 is that the gap 16 is set to 0 in a portion where the gap 16 is unnecessary. Moreover, the reason why the upper limit of the size W of the gap 16 is set to 70 μm is that when the gap is exceeded, the appearance is deteriorated. In the present embodiment, as described above, the size W of the gap 16 is set to be 0 at the positions of the bone portion 28 and the both end portions 34 in the piece 14. It should be noted that the gap 16 at the positions of both end portions 34 of the piece 14 may not be set to 0 depending on the method of releasing air during vulcanization.

  The gap 16 may be provided between the adjacent pieces 14 in one sector 12 or may be provided between the adjacent pieces 14 between different sectors 12. The gap 16 does not need to be provided between all adjacent pieces 14 and may be provided in a portion where a crown bear is likely to occur during vulcanization. Therefore, the pieces 14 from which the bone portion 28 does not protrude may be adjacent to each other.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. When the tire 20 (FIG. 5) is vulcanized using the tire vulcanization mold 10 according to the present embodiment, a raw tire (not shown) and tire vulcanization are used to prevent the generation of crown bears. Air between the mold 10 for sulfur is removed. As shown in FIG. 4, the end surfaces 38 of the two adjacent pieces 14 and the groove 40 (FIG. 3) are joined together to form an air intake passage for air bleeding. Aspirate air. Since the groove portion 40 communicates with the gap 16 between the adjacent pieces 14, the air between the raw tire (not shown) and the tire vulcanization mold 10 is extracted by sucking air in this way. be able to.

  Here, in the tire vulcanization mold 10, the gap 16 between the adjacent pieces 14 is discontinuous in the tire width direction, and the gap 16 is continuously provided over the entire length in the tire width direction. Thus, the range in which the gap 16 is provided is narrowed. By simply combining the pieces 14, the adjacent bone portions 28 come into contact with each other, and the gaps 16 in the portions other than the bone portions 28 are accurately set. Therefore, the variation in the gaps 16 between the adjacent pieces 14 can be easily reduced. be able to.

  In addition, by setting an appropriate gap 16 between the pieces 14 located in a portion where the crown bear is likely to occur, the occurrence of the crown bear can be prevented and deterioration of the appearance can be suppressed. Since the size of the gap 16 is 0 to 70 μm, the size of the protruding portion 42 (FIG. 5) of rubber formed on the tire surface corresponding to the gap 16 between the pieces 14 is suppressed to a minimum. The generation of crown bears can be suppressed. Since the size W of the gap 16 is 0 at the position of the bone portion 28, the protruding portion 42 does not occur in the circumferential main groove 26.

  Specifically, since the size W of the gap 16 between the pieces 14 is set to be 0 at the position of the bone portion 28, the circumferential main groove continuous in the tire circumferential direction is formed in the tread portion 18. 26 can be formed. In addition, since the gap 16 is provided between the pieces 14 corresponding to only the tread surface where the crown bear is easily noticeable in the tread portion 18, when cleaning the piece 14 to which the rubber is attached, Only the area of the gap 16 needs to be cleaned, and the operation becomes easy.

  FIG. 5 shows an example of the tire 20 immediately after being vulcanized and molded using the tire vulcanization mold 10. The tire 20 is, for example, a pneumatic tire. Since the tire 20 is vulcanized and molded using the tire vulcanization mold 10, the generation of crown bear is suppressed and the appearance is improved. The protruding portion 42 of rubber remaining on the surface of the tire 20 after vulcanization molding is removed as necessary. The protruding portion 42 is intermittently formed in the tire width direction and is not formed in the circumferential main groove 26, so that the drainage performance of the circumferential main groove 26 is not affected, and the protruding portion The removal of 42 is also easy.

(Other embodiments)
In the illustrated example, the tire vulcanization mold 10 has nine sectors 12, and one sector 12 has a plurality of pieces 14, but the number of sectors 12 and the pieces 14 for each sector 12 are shown. The number of is not limited to this.

  In the above configuration, at least one bone portion 28 of the adjacent piece 14 protrudes from the end surface 32 of the piece 14 in the tire circumferential direction toward the bone portion 28 of the other piece 14, This means that the case where the opposing bone portions 28 of both pieces 14 protrude is included. That is, the protruding amount of each bone portion 28 may be, for example, half of the size W of the gap 16 to be set.

  Further, in FIG. 4, all the bone portions 28 are drawn so as to protrude in one of the tire circumferential directions, but the present invention is not limited to this, and the bone portion 28 protruding in one of the tire circumferential directions and the tire circumferential direction The bone portions 28 protruding to the other side may be provided alternately.

  Furthermore, in the illustrated example, the number of the bone portions 28 is three, but this is changed according to the set number of the circumferential main grooves 26. Moreover, the convex shape provided in the piece 14 is not restricted to the bone part 28, You may provide the convex part for forming a horizontal groove, a sipe, etc. (not shown).

10 Tire vulcanization mold 12 Sector 14 Pieces 16 Clearance 20 Tire (Pneumatic tire)
26 circumferential main groove 28 bone W gap

Claims (5)

A tire vulcanization mold configured by arranging a plurality of pieces side by side in one sector and arranging the plurality of sectors in a circular shape,
A tire vulcanization mold in which a gap for removing air from a raw tire during vulcanization of a tire is provided discontinuously between adjacent pieces.   The tire vulcanization mold according to claim 1, wherein a size of the gap is 0 to 70 μm. The piece is provided with a bone portion for forming a circumferential main groove,
The tire vulcanization mold according to claim 1 or 2, wherein a size of the gap is set to be 0 at a position of the bone portion.   The bone part of at least one of the adjacent pieces protrudes from the end surface in the tire circumferential direction of the piece toward the bone part of the other piece, and the bone parts are in contact with each other. Mold for tire vulcanization.   A pneumatic tire formed by vulcanization using the tire vulcanization mold according to any one of claims 1 to 4.

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