JP2015164780A - Mold for vulcanization of tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for vulcanization of a tire, which more sufficiently suppresses spew clogging induced in a vent hole of the mold due to disconnection of a spew, compared to a conventional mold, and which prevents decrease in work efficiency.SOLUTION: The mold for vulcanization of a tire has a molding surface corresponding to the profile of a tire outer surface, in which a plurality of bent pieces having a bent hole having one end open to the molding surface side and the other end open outside the mold for vulcanization of a tire are disposed, and an inner wall surface of the bent hole, near the molding surface side, is subjected to surface processing to decrease surface friction with rubber. Further, in the mold for vulcanization of a tire, the molding surface near the bent hole is subjected to surface processing. In the mold for vulcanization of a tire, a region of the molding surface within a radius of 1 to 4 mm from the center of the bent hole is subjected to surface processing. The surface processing is fluorine processing or plating; and the plating is chromium plating.

Description

  The present invention relates to a tire vulcanization mold used in the manufacture of a pneumatic tire.

  In the manufacturing process of a pneumatic tire, a tire vulcanizing mold (hereinafter also simply referred to as “mold”) on which a raw cover is set is closed and heated while pressing the raw cover against the molding surface of the mold. Vulcanization molding is performed by applying pressure.

  At this time, if air remains between the molding surface of the mold and the raw cover, a bear is generated on the surface of the vulcanized tire. In view of this, a vent hole for venting air is provided on the molding surface of the mold to suppress the generation of bears (for example, Patent Documents 1 and 2).

  However, when the rubber of the raw cover enters the vent hole, the spew 20 as shown in FIG. 3 is formed on the tire surface after vulcanization. The spew 20 is removed by a cutter or the like in the subsequent finishing process. However, depending on the tire size, when the mold is opened after vulcanization, the spew 20 is cut in the vent hole and clogged in the vent hole. Sometimes (spy clogging).

  When such a spew clogging occurs, it becomes impossible to exhaust air from the vent hole and it becomes easy to generate bears. When spew clogging occurs, vulcanization molding is interrupted and the vent hole of the mold is stopped. It is necessary to perform a spew hole to remove the clogged spew, which reduces work efficiency.

  Therefore, conventionally, various means as described below have been adopted in order to suppress the occurrence of such spew clogging.

  For example, by applying silicon to the surface of the raw cover before being set in the mold, the spew can be easily removed from the vent hole of the mold. Also, the tire is slowly extracted from the vulcanizer by slowing down the speed when opening the mold after vulcanization. In addition, means such as making a raw cover using rubber blended so that spew breakage is unlikely to occur have been taken.

  However, even if these means are employed, spew clogging cannot be sufficiently suppressed, and it has been difficult to improve work efficiency.

JP 2012-139830 A JP 2013-244732 A

  An object of the present invention is to provide a tire vulcanization mold that suppresses spew clogging generated in a vent hole of a mold due to spew breakage more sufficiently than before and does not cause a reduction in work efficiency. .

The invention described in claim 1
A tire vulcanization mold having a molding surface corresponding to the shape of the tire outer surface,
A plurality of vent pieces having a vent hole whose one end is on the molding surface side and the other end is open to the outside of the tire vulcanizing mold,
A tire vulcanization mold characterized in that surface processing for reducing surface friction with rubber is performed in the vicinity of the molding surface side of the inner wall surface of the vent hole.

The invention described in claim 2
The tire vulcanization mold according to claim 1, wherein the surface processing is performed on a molding surface in the vicinity of the vent hole.

The invention according to claim 3
3. The tire vulcanization mold according to claim 2, wherein the surface processing is applied to a region having a radius of 1 to 4 mm from the center of the vent hole on the molding surface.

The invention according to claim 4
The tire vulcanization mold according to any one of claims 1 to 3, wherein the surface processing is surface processing by fluorine processing or plating processing.

The invention described in claim 5
The tire vulcanization mold according to claim 4, wherein the plating process is a chrome plating process.

The invention described in claim 6
The tire vulcanization mold according to any one of claims 1 to 5, wherein the surface treatment is performed when the tire vulcanization mold is manufactured.

  According to the present invention, it is possible to provide a tire vulcanization mold that suppresses spew clogging generated in a vent hole of a mold due to spew breakage more sufficiently than before and does not cause a reduction in work efficiency. .

1 is a partial cross-sectional perspective view showing a part of a tire vulcanization mold according to an embodiment of the present invention. It is an expanded sectional view of the vent piece of the tire vulcanization mold. It is a figure showing typically the tire after vulcanization.

  Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

  FIG. 1 is a partial cross-sectional perspective view showing a part of a tire vulcanization mold according to the present embodiment, and FIG. 2 is an enlarged cross-sectional view of a vent piece of the tire vulcanization mold.

  As shown in FIG. 1, the main body 11 of the tire vulcanization mold 1 according to the present embodiment is configured by combining a number of members, as in the conventional tire vulcanization mold, and a mold ring 11a. , A tread ring 11b, a bead ring (not shown), and a clamp ring.

  A plurality of vent pieces 12 are provided on the mold ring 11a and the tread ring 11b.

  That is, as shown in FIG. 2, a socket 11 d penetrating the main body 11 is formed on the molding surface C of the main body 11. The socket 11d is formed with a holding portion 11e and a pedestal portion 11f, and the vent piece 12 fitted into the socket 11d has one end surface 12b and a molding surface C together with the main surface 11c of the main body 11. Thus, it is held by the holding part 11e.

  The vent piece 12 is a cylindrical member having a vent hole 12a. One end of the vent hole 12a is on the molding surface C side of the tire vulcanizing mold 1, and the other end is the outside of the tire vulcanizing mold 1. Is open. By providing such a vent piece 12, the air remaining between the molding surface C and the raw cover during vulcanization molding is discharged to the outside of the mold through the vent hole 12a.

  However, the tire vulcanization mold 1 according to the present embodiment is provided with a surface treatment that reduces surface friction with rubber in the vicinity of the molding surface C side of the inner wall surface 12d of the vent hole 12a. This is different from the conventional tire vulcanizing mold 1.

  As a result, the surface friction between the rubber of the raw cover and the vent piece 12 is reduced on the surface-treated surface, and the spew is cut in the vent hole 12a when the vulcanized tire is removed from the tire vulcanizing mold. Can be smoothly extracted without causing spew clogging. As a result, it is possible to prevent the occurrence of bears due to spew clogging.

  In addition, it is not necessary to perform a spew hole to remove spew clogged in the vent hole 12a, and further, the opening speed of the tire vulcanizing mold can be made faster than before, which contributes to an improvement in manufacturing efficiency. it can.

  In addition, the surface treatment smoothes the rubber flow during vulcanization and makes it difficult to damage the surface of the vent piece. Maintenance efficiency such as replacement can be reduced and manufacturing efficiency can be further improved.

  The surface processing is not particularly limited as long as surface friction with rubber can be reduced, but fluorine processing is preferable. Plating is also preferable, and chrome plating is particularly preferable among them.

  In the present embodiment, this surface treatment is also preferably performed on the molding surface C of the tire vulcanizing mold 1, and in particular, it is performed on the molding surface C in the vicinity of the vent hole 12a. It is preferable that the rubber flow during vulcanization is sufficiently smooth.

  At this time, if the region 12c to be subjected to surface processing becomes narrower than the radius 1 mm from the center D of the vent hole 12a, it is difficult to appropriately reduce the surface friction with the raw cover. On the other hand, if the width is larger than 4 mm, the effect is saturated and the cost of surface processing increases. For this reason, it is preferable that the area | region 12c to which surface processing is given is an area | region with a radius of 1-4 mm from the center D of the vent hole 12a.

  In addition, it is preferable to perform this surface processing at the time of manufacture of the metal mold | die 1 for tire vulcanization from a viewpoint that a processing process can be performed easily.

  Further, in the above embodiment, surface processing is performed only in the vicinity of the molding surface side of the inner wall surface of the vent hole. However, surface processing is performed on the entire inner wall surface of the vent hole according to the spew condition that occurs. May be. In addition, when surface processing is performed on the molding surface, surface processing may be performed on the entire molding surface.

  Hereinafter, the present invention will be described more specifically with reference to examples.

1. Preparation of test tire Tire size (5585) 195 was the same as the test tires of Test Examples 1 to 3, except for the presence or absence of surface processing of the tire vulcanization mold and the presence or absence of silicon processing of the raw cover. 100 tires each of / 65R15 WM01 were produced.

(1) Test Tire of Test Example 1 The test tire of Test Example 1 was obtained by vulcanizing and molding the raw cover as it was using a conventional tire vulcanization mold that had not been surface-treated.

(2) Test Tire of Test Example 2 The test tire of Test Example 2 was obtained by vulcanizing a raw cover with silicon applied on the surface using a conventional tire vulcanization mold that was not surface-treated.

(3) Test Tire of Test Example 3 The test tire of Test Example 3 is a tire vulcanization mold in which the surface processing (fluorine processing) described above is performed on the inner surface of the vent piece and the region near the opening of the molding surface. The raw cover was vulcanized as it was.

2. Evaluation (1) Number of Bare Generation Products The appearance of 100 tires after vulcanization was visually sensory-evaluated, and the number of tires in which bears were generated was counted. The results are shown in Table 1.
(2) Number of spew clogging After vulcanization molding, spew holes were carried out to count the places where spook clogging occurred. The results are shown in Table 1.

  From Table 1, in the case of Test Example 3 using a tire vulcanizing mold in which the inner surface of the vent piece and the area near the opening of the molding surface are subjected to fluorine processing, no generation of bare or spew clogging occurs, and It was confirmed that the generation of bears due to clogging can be prevented.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

DESCRIPTION OF SYMBOLS 1 Tire vulcanization metal mold | die 11 Main body 11a Mold ring 11b Tread ring 11c Main surface 11d Socket 11e Holding part 11f Pedestal part 12 Vent piece 12a Vent hole 12b End surface 12c of a vent piece Area 12d where surface processing is performed Inner wall surface 20 of a vent hole Spew C Molding surface D Center of vent hole

Claims (6)

A tire vulcanization mold having a molding surface corresponding to the shape of the tire outer surface,
A plurality of vent pieces having a vent hole whose one end is on the molding surface side and the other end is open to the outside of the tire vulcanizing mold,
A tire vulcanization mold, wherein a surface treatment for reducing surface friction with rubber is applied in the vicinity of the molding surface side of the inner wall surface of the vent hole.   The tire vulcanization mold according to claim 1, wherein the surface processing is performed on a molding surface in the vicinity of the vent hole.   3. The tire vulcanization mold according to claim 2, wherein the surface processing is applied to a region having a radius of 1 to 4 mm from the center of the vent hole on the molding surface.   The tire vulcanization mold according to any one of claims 1 to 3, wherein the surface processing is a surface processing by fluorine processing or plating processing.   The tire vulcanization mold according to claim 4, wherein the plating process is a chrome plating process.   The tire vulcanization mold according to any one of claims 1 to 5, wherein the surface treatment is performed when the tire vulcanization mold is manufactured.

Images