JPS60141351A - Production of vulcanizing mold for tire - Google Patents

Abstract

PURPOSE:To remove wire-shaped bodies from a mold inserted therein by casting with the wire-shaped bodies to form fine holes and to obtain efficiently a mold for vulcanization permitting good gas venting by bridging the wire-shaped bodies to the grooves of a core having the grooves of the same shape as the shape of a product tire on the outside circumferential surface, enclosing the core with a master mold and pouring a molten metal into the space between the inside surface of the master mold and the outside surface of the core. CONSTITUTION:A core 1 which has grooves 3 of the same shape as the tread and shoulder plane of a product tire on the outside circumferential surface and is formed with many pairs of recesses 6, 7 to opposing side walls 4, 5 of the grooves 3 is prepd. Both ends of wire-shaped bodies 8 are respectively inserted and embedded into respective pairs of the recesses 6, 7 and the grooves 3 are bridged by the bodies 8. The circumference of the core 1 is enclosed with a master mold 13 and a hollow part 14 is formed between the inside surface of the master mold and the outside surface of the core. A molten metal is poured into the part 14 and is solidified to form a mold 15, by which the central parts of the bodies 8 are inserted into the bone part 16 of the mold 15. After the mold 15 is separated, the bodies 8 are removed to form fine holes 17 in the bone part 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a vulcanized mold for tires.

In general, tire vulcanization molds have a large number of so-called vent holes that extend in the radial direction and have small diameters in order to remove debris generated from the green tire during vulcanization. For this reason, the outer surface of the vulcanized tire has protruding,
A large number of so-called spews are formed. Since such spills impair the appearance of the product tire, they are either cut off by a picker in a subsequent process, or such cutting and removal work is very troublesome. For this reason, vent holes extending approximately in the axial direction of the tire are formed in the protruding bones of the mold that correspond to the grooves on the tire tread and shoulder surface.
It has been desired to form spills within the grooves of product tires. In order to form vent holes in such a mold, machining, such as a hunt-trill operation, is performed on the mold, but the following problems arise. First of all, for grooves with complex shapes, the protruding parts defined by the grooves may interfere with the work of adjacent objects.
There is a problem that workability is poor. Second, there is a problem in that it is difficult to manufacture the vent hole with a diameter of, for example, 11,010 mm or less. Third, during vulcanization, gas collects at the proximal end of the bone of the mold, so it is preferable to place the vent hole closer to the proximal end of the bone. Since the vent hole is obstructed, the closer to the proximal end the more difficult the forming operation becomes.As a result, the vent hole can only be formed at the tip or center of the bone, resulting in a problem that the gas venting effect is reduced.

This invention was made by focusing on the above-mentioned problems.
It is an object of the present invention to provide a method for manufacturing a tire vulcanization mold that can produce a vulcanization mold with a good degassing effect with high efficiency.

This objective includes the step of preparing a core having grooves on the outer circumferential surface having the same shape as the tread and shoulder surfaces of the product tire, and having multiple pairs of recesses formed on several opposing side walls; A process of inserting and embedding both ends of a linear body into the recess of each month and bridging the groove with the linear body, and surrounding the core with a main mold to connect the inner surface of the main mold and the outer surface of the core. a process of forming a hollow part between the grooves, and a process of casting the central part of the linear body into the bone part of the mold solidified in the groove by injecting and solidifying molten metal into the hollow part to form a mold. After separating the mold from the core and main mold,
This can be achieved by including the steps of extracting the linear body from the mold and forming pores in the bone portion of the mold.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1.2, 1 is a core made of foamed gypsum or the like, and this core 1 has an annular shape, and has the same shape as one half of the product tire divided into two at its equatorial plane. The outer peripheral surface 2 of this core 1 is formed with a large number of grooves 3 having substantially the same shape as the tread and shoulder surface of the product tire.

A large number of pairs of recesses 6, 7 are formed in the mutually opposing side walls 4.5 of the groove 3. Each of the recesses 6, 7 has its radially outer end open to the outer circumferential surface 2. These recesses 6 and 7 may be formed by providing projections on the mold for molding the core 1 and inverting these projections to form the recesses 6 and 7. It may be formed by cutting off after forming the child 1. 8 is the paired recess 8
．． 7 and is substantially parallel to the outer circumferential surface 2. This linear body 8 is made of a material that will not be fused even if it comes into contact with molten metal, which will be described later. It consists of a heat-resistant solid lubricant layer attached to the surface. As the wire material, wire, insect pin, wire, etc. are used, and as the solid lubricant, metal oxides such as graphite, molybdenum disulfide, zinc oxide, aluminum oxide, mica,
Talc etc. are used. Note that when the wire is made of carbon fiber, the lubricant layer is not necessary. Both ends of this linear body 8 are recesses 6 for each month, ? After being inserted into the recesses 6 and 7, the filling bodies 9 and 10 made of foamed gypsum or the like are filled into the recesses 6 and 7, so that both ends of the linear body 8 are inserted into the recesses 6.
, 7 to bridge the groove 3 as shown in FIG. Alternatively, both ends of the linear body 8 are buried in plaster blocks complementary to the recesses 6 and 7, and then these gypsum blocks are inserted into the recesses 6 and 7, so that both ends of the linear body 8 are recessed. Place 6
, 7 may be buried. This linear body 8 is preferably buried at a position where the distance S from the outer circumferential surface 2 of the core l is 2 mm or less. After the linear body 8 is attached to the core 1, the core 1 is placed on the flat fill so that its divided surface is attached to the flat fill. Next, the mold 12 is placed over the core 1, so that the main mold 13 composed of the flat 1i+1 and the mold 12 surrounds the core 1, and the main mold 13 is made up of the flat 1i+1 and the mold 12. ! ! A hollow portion 14 is formed between the inner surface of the core 1 and the outer surface of the core 1. Once the hollow portion 14 is formed in this manner, molten metal made of aluminum alloy, zinc alloy, etc. is injected into the hollow portion 14. At this time, even if the linear body 8 comes into contact with the molten metal, it does not fuse with the molten metal and maintains its shape. and,
When this molten metal cools and solidifies, a mold 15 is formed. At this time, the molten metal flows into the groove 3 and solidifies, so that a protruding bone part 16 is formed on the inner surface of the mold 15 in a complementary relationship with the groove 3, and this bone part 16 The center portion of the linear body 8 is cast, and as a result, the linear body 8 is firmly held in the mold 15. Next, 1,000m11. After removing the formwork 12, the mold 15 and the core l are separated and the mold 15 is taken out. At this time, since the linear body 8 is firmly held at its center or by the bone part 16, it is transferred from the core l to the mold 15, and its both ends are pulled out from the filling body 8.10 and placed in the bone part 16. 3rd from the outside
Protrude as shown. Next, one of both ends of the linear body 8 protruding from the outer surface of the bone portion 16 is pulled, and the linear body 8 is extracted from the bone portion 16 . At this time, since the linear body 8 is made of a wire having a lubricant attached to its outer periphery, a large force is not required to pull out the linear body 8, and the work efficiency is improved. By this extraction, a large number of vent holes 17 are formed at the proximal end of the bone portion 16, and each vent hole 17 is a through hole with both ends open, for example, a diameter of 1.2 mm.
When a green tire is vulcanized using such a mold 15, the gas generated during vulcanization flows into the vent hole 17 from both openings, and
In the above-mentioned hole 17, the rubber of the raw tire is also placed in both openings.
Inflow from -1. This inflowing rubber later becomes a spill, and since the diameter of this spill is as small as the diameter of the vent hole 17, it does not impede the drainage performance of the product tire. Here, the gas is collected in the vicinity of the outer peripheral surface of the green tire, that is, at the base end of the bone portion 16, but if the distance 1llllS is 2 or less as described above, this gas will not remain and will surely flow into the vent hole 17. flowing into
The occurrence of small concave portions called bears can be reliably prevented.

As explained above, according to the present invention, a vulcanizing mold with good degassing effect can be manufactured with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the invention, FIG. 2 is a perspective view showing a part of the core, and FIG. 3 is a perspective view showing a part of the mold. l... Core 2... Outer peripheral surface 3... Groove 4.5... Side wall 6.7... Recess 8... Linear body 13... Main mold 14... Hollow Part 15...Mold 18...Bone part 17...Pore (vent hole) Patent applicant Brideston Tire Co., Ltd. Agent Patent attorney Ta 1) Toshio Figure 1 Figure 3 Figure 2 Figure 1 Ding Thunta Ying J Seikun - (Spontaneous) February 1711, Showa 5θ Director-General of the Public License Agency Wakasugi Wainu Indication of the case Patent application 1986-249988 2 Name of the invention Method for manufacturing vulcanized molds for tires 3 Make amendments Relationship with the Patent Case Address of Patent Applicant: 11-10-1, Kyo V11-chome, Chuo-ku, Tokyo Name (5
27) Brideston Tire Co., Ltd. 4th Jllj person
160 Address: 7-13-5 Nishi-Shinjuku, Shinjuku-ku, Tokyo Column 6 of “Detailed Description of the Invention” in the specification subject to amendment Contents of the amendment (1) In the specification No. 7, the r diameter is indicated on line I8. It says "from 1.2", correct it to "diameter from 0.7". that's all

Claims (1)

[Claims] A process of preparing a core having grooves on the outer peripheral surface that have the same shape as the trend and shoulder surface of the product tire, and many pairs of recesses formed on several opposing side walls, and A step of inserting and burying both ends of the linear body and bridging the groove with the linear body, and surrounding the core with a main mold to form a hollow space between the inner surface of the main mold and the outer surface of the core. forming a mold by injecting and solidifying molten metal into the hollow part to form a mold (step 11 of casting the central part of the linear body into the bone part of the mold solidified in the groove I); A method for manufacturing a vulcanizing mold for a tire, comprising the steps of separating the mold from a core and a main mold, and then extracting a linear body from the mold and forming pores in the bone part of the mold.