JP2001150441A - Mold for vulcanizing and molding tire and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for vulcanizing and molding a tire constituted so as not only to be capable of manufacturing a tire having good appearance and high dimensional accuracy but also to be capable of inexpensively producing especially a single product mold having a tread pattern simple in design and a method of manufacturing the same. SOLUTION: A molten metal material 22 is injected in the recessed parts 21a, which are formed on the profile surfaces of the mold rough material of a first sector 20 molded by a first shot by die casting, by a second shot so as to leave a processing flange for processing a tread pattern. The tread pattern is applied to the part of the processing flange of the mold rough material thus molded by machining or discharge processing. Exhaust ports 25 communicating with the atmosphere are formed on the lines of the cast joint parts 24 of the sector mold thus molded in a normal line direction from the back surface of the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire vulcanization mold and a method for producing the same, and more particularly to a purees mold (a fine vent hole that does not allow molten rubber material to flow out during tire vulcanization). And molds with exhaust grooves) for tire vulcanization molding, in which the profile surface of a tire vulcanization molding die with a relatively simple design tread pattern is processed by machining or electric discharge machining The present invention relates to a mold and a method for manufacturing the mold.

[0002]

2. Description of the Related Art Conventionally, a sector mold used as one of tire vulcanization molding dies is composed of a plurality of pieces formed with irregularities corresponding to at least a profile surface (molding surface) of a tread portion of a product tire. Are mounted adjacent to each other on the back block to form one sector, and a plurality of sectors are connected to each other to form an annular sector mold.

[0003] On the other hand, when vulcanizing and molding a tire using such a sector mold, air traps and gas are generated between the outer peripheral surface of the tire and the molding surface of the mold, and the air and gas are generated in the product tire. It is known that a minute recessed portion is formed on the surface of the device to cause a product defect. From this,
Conventionally, a through-hole for venting air, called a vent hole, and a groove for exhaust are formed on a molding surface of a mold.

However, a rubber material flows into the vent hole and the exhaust groove during vulcanization of the tire and forms spews (burrs, whisker-like rubber projections) on the surface of the product tire. For this reason, finishing work to remove the spew after molding is required, and after removing the spew, the trace of the tire product is left behind and the appearance of the tire product is damaged,
There was the problem of increasing tire noise.

[0005] In recent years, tires with excellent appearance have been developed.
In order to reduce the occurrence of defective products during tire vulcanization molding, a pureless mold (slit vent) having no vent hole or exhaust groove formed on the molding surface is used.

[0006] The invention of the pures mold is described in, for example, Japanese Patent Application Laid-Open No. 4-223108 (Title of Invention:
Mold for vulcanizing an unvulcanized tire carcass, method for manufacturing the mold, method for vulcanizing a tire using the mold, and Japanese Patent Application Laid-Open No. H10-24423 (Title of Invention: Mold for tire vulcanization molding) Mold and its manufacturing method).

The former invention is a method of assembling a back block in which a tread pattern of a tire is divided for each pitch, and sucking air existing between the tire and a mold from outside through a gap provided between the back blocks. In the latter invention, the dissimilar metal (SS400) is cast in the base metal (aluminum) of the pattern piece and is formed by the difference in linear thermal expansion coefficient at the temperature (160 ° C.) at the time of tire vulcanization molding. This is a method of discharging air using a gap.
In addition, as a slit vent mold, there is a method of removing air by providing a step between pieces by machining or inserting a spacer between pieces.

[0008]

However, the above-mentioned invention has a problem that it is difficult to secure proper air bleeding at an arbitrary position, and a vacuum device or the like is necessarily required as an exhaust means. In the above invention, a volume necessary for generating a gap due to a difference in linear thermal expansion coefficient between different metals is required, and it is difficult to secure a required gap amount at an arbitrary position. It is difficult to pull out.

Further, the conventional purees mold is advantageous in terms of cost when a complicated pattern shape and a plurality of same molds are manufactured, but the simple pattern can be used with a simple pattern.
There was a problem that it was difficult to produce only the surface cheaply and in a short time.

[0010] It is an object of the present invention to form a gap at any position of a mold to ensure required exhaust performance, thereby making it possible to manufacture a tire having a good appearance and high dimensional accuracy. It is an object of the present invention to provide a tire vulcanization molding die and a method for manufacturing the same, which enable a single-piece mold having a simple design to be manufactured in a short time and at low cost.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a tire vulcanizing mold according to the present invention, which comprises a plurality of shots formed by die casting in a plurality of shots. A tire vulcanization molding die which constitutes a molding die by mounting a sector on a back block and arranging it in a ring shape, which is divided into a plurality of shots by the die casting and cast and laminated. The gist is that a processing margin for processing a tread pattern is formed on a profile surface of a mold rough material integrated with a sector, and the tread pattern is processed by machining or electric discharge machining in the processing margin.

In another tire vulcanizing mold according to the present invention, a plurality of pieces, which are formed by casting and laminating a plurality of shots by die casting, are mounted on a back block and arranged in a ring. A tire vulcanization molding die constituted by forming a molding die by performing a tread pattern on a profile surface of a plurality of pieces that are cast and laminated in a plurality of shots by the die casting. And that the tread pattern is machined by machining or electric discharge machining.

Further, according to the method of manufacturing a tire vulcanization molding die of the present invention, a first shot is formed by die casting on a first split die to form an integral part of a sector having an uneven tire profile surface shape. Forming a rough mold material, forming a profile surface with a processing allowance for processing a tread pattern by performing a second shot of the molten metal material in a concave portion of the rough mold material, and forming the profile surface with the first shot and the second shot.
Form a fine gap due to solidification shrinkage of the metal material at the joint of the mold coarse material with the shot, and process the tread pattern by machining or electric discharge machining instead of the profile surface machining allowance. The gist of the present invention is to form an exhaust hole communicating with the atmosphere from the back side of the mold in a normal direction on the joint line.

Further, another method of manufacturing a tire vulcanization mold according to the present invention is a method for producing a first split mold by die casting.
A shot is used to form a divided first piece block partially having an uneven tire profile surface shape, and a second shot of a molten metal material into a recess of the first piece block to process a tread pattern. Forming a profile surface provided with a processing allowance, forming a fine gap due to solidification shrinkage of a metal material in a joint portion of the piece block between the first shot and the second shot, The gist of the invention is to form a tread pattern by machining or electric discharge machining, and to form an exhaust hole communicating with the atmosphere in the normal direction from the back side of the mold on the joint line of the piece block.

According to the present invention, a sector-integrated mold crude material having a partially uneven tire profile surface shape is formed by performing a first shot on a first split mold by die casting. A second shot of the same type of molten metal is formed in the concave portion of the mold coarse material to form a profile surface provided with a processing allowance for processing a tread pattern, and the profile of the mold coarse material of the first shot and the second shot is formed. Since a fine gap is formed at the joint by solidification shrinkage of the metal material, a gap that can secure the required exhaust performance at any position in the mold is formed, and a tire with good appearance and high dimensional accuracy is manufactured. Can be done.

Further, a tread pattern is machined by machining or electric discharge machining instead of machining of the profile surface, and an exhaust hole communicating with the atmosphere in a normal direction from the back side of the mold is provided on the joint line of the mold coarse material. So that
Like a tire mold for motor sports, it is a single-piece mold without a sample. Even a tread pattern with a simple design can easily process all of the profile surface and can be manufactured in a short time at low cost.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic plan view of a split-type tire vulcanizing mold (sector mold) embodying the present invention.
FIG. 2 is an explanatory view of a conventionally known mold supporting apparatus. As a first embodiment of the sector mold 1, a plurality of sectors (two in this embodiment) are mounted on a back block 3. However, the number is not particularly limited).

In the second embodiment of the sector mold 1, a plurality of pieces having irregularities corresponding to at least a profile surface (molding surface) of a tread portion of a product tire are formed adjacent to each other and formed on a back block 3. One sector 2 is constituted by mounting, and this sector 2
Are connected to each other to form an annular sector mold.

When the tire is vulcanized by using the sector mold 1, the tire is mounted on a conventionally known mold supporting device 5 as shown in FIG.

In the mold supporting device 5 shown in FIG. 2, the divided sectors 2 are formed on the inner tapered surface 8 of the outer ring 7 suspended below the outer peripheral edge of the smooth supporting plate 6 via the segments 9. It is attached so that it can expand and contract toward the center,
This sector 1 has a back block 3 mounted thereon. On the upper part of the sector 2, an upper mold 11 which can be moved up and down via an upper plate 10 is provided. On a lower base plate 12, a lower mold 13 is provided.
Are arranged.

When vulcanizing the tire W, each sector 2 is moved in the centripetal direction (inward direction), and the upper mold side mold 11 and the lower mold side mold 13 are brought into close contact with the upper and lower ends of each sector 2. Thus, the tire W is vulcanized and formed, and when the vulcanization is completed, each sector 2
Is moved outward and the upper mold side mold 11 is moved upward to release the formed tire W.

As shown in FIGS. 3, 6, and 7, the sector-integrated mold according to the first embodiment of the present invention has a first shot formed by a first shot by die casting.
A second shot of the molten metal material 22 is made in the concave portion 21 a of the profile surface 21 of the mold crude material of the sector 20 while leaving a processing allowance for processing the tread pattern.

Then, the tread pattern 23 is processed by machining or electric discharge machining on the portion of the processing margin of the thus-molded rough material.

The tread pattern 23 is machined by, for example, using NC data (numerical control data) for simultaneous 5-axis machining created from three-dimensional modeling data. Also, electric discharge machining,
The tread pattern data is input to the control device in advance, and the tread pattern is automatically processed.

Then, on the line of the joint portion 24 of the sector mold thus formed, an exhaust hole 25 communicating with the atmosphere in the normal direction from the back side of the mold is formed. A fine gap of 0.005 to 0.06 mm is formed in the joint portion 24 of the cast and laminated mold coarse material due to solidification shrinkage of the cast metal material, and air generated during vulcanization is generated from the joint portion 24 and the exhaust hole 25. And only gas will be emitted.

As described above, in the first embodiment of the present invention, since a sector-integrated mold is used without using a piece for each pitch, no combination line is generated for each pitch, and the back block 3 is not used. It is possible to assemble the sector mold simply by mounting it on the mold.

In the first embodiment of the present invention, the entire profile surface can be easily formed by machining or electric discharge machining even in a single-piece mold having no tread and having a simple tread pattern, such as a tire mold for motor sports. It can be processed and can be manufactured in a short time at low cost.

Further, since it is not necessary to manufacture an expensive die-casting pattern insert, it is possible to manufacture a purees mold with low cost and quick delivery.

Whether the processing of the tread pattern is performed by machining (direct engraving) or electric discharge machining as described above is selected according to the form of the tread pattern.

Further, as a second embodiment of the present invention,
Similarly to the first embodiment, a first shot is formed on a first split mold by die casting to form a split first piece block partially having an uneven tire profile surface shape. Then, a second shot of the molten metal material is formed in the recess of the first piece block to form a profile surface provided with a processing allowance for processing a tread pattern, and a piece block of the first shot and the second shot is formed. Fine gaps are formed in the joint by solidification shrinkage of the metal material.

Further, a tread pattern is machined by machining or electric discharge machining instead of machining of the profile surface, and an exhaust hole communicating with the atmosphere in a normal direction from the back side of the mold is formed on the joint line of the piece block. Thus, a tire vulcanization mold can be manufactured.

Also in the case of this piece assembling method, the entire profile surface can be easily formed by machining or electric discharge machining even with a simple tread pattern having a simple design and no sipe, such as a tire mold for motor sports. Can be processed.

Further, in the above-described embodiment, the first shot and the second shot of die casting use the same kind of aluminum alloy for die casting. Is possible. Preferably, the back block 4 is made of an aluminum alloy or steel.

[0035]

The present invention is constructed as described above, and has the following excellent effects. . Like a motor sports tire mold, a tread pattern with a simple design without a sipe, which is a single-piece mold, can be easily processed by machining or electric discharge machining on the entire profile surface, so it can be produced inexpensively in a short time, especially The time required to manufacture a purees mold by a conventional method can be reduced to 1/3 to 1/4. . By forming a gap at any position in the mold to ensure the required exhaust performance, a tire having good appearance and high dimensional accuracy can be manufactured. . When casting and laminating pieces with the same type of molten metal material,
Since a minute gap due to solidification shrinkage of the metal material of the second shot can be formed in the joint portion of the piece made of the metal material cast between the shot and the second shot, it is not necessary to create a gap between the piece blocks during assembly. Absent. . The clearance amount (slit amount) of the piece block alone can be confirmed at room temperature, and the required exhaust performance can be guaranteed. . The gap can be set at any desired position, and the amount of the gap can be controlled by the casting conditions for the second shot. . Since the finishing of the tire surface is unnecessary, a tire having good appearance and high dimensional accuracy can be manufactured, and the occurrence of defective tires during vulcanization molding can be reduced. . Further, a step of removing the spew after vulcanizing the tire is not required, and the appearance of the tire can be improved without leaving traces of the spew that deteriorate tire noise on the tire surface.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a sector mold of the present invention in which a plurality of sectors are connected to each other to form an annular shape.

FIG. 2 is a schematic sectional view of a mold supporting device on which a sector mold is mounted.

FIG. 3 is a perspective view of a one-sector integral unit showing the first embodiment of the puree mold of the present invention.

FIG. 4 is a plan view of a one-sector integral unit showing the first embodiment of the puree mold of the present invention.

FIG. 5 is a sectional view taken along the line AA of FIG. 4;

FIG. 6 is a perspective view of a first coarse sector material shot by die casting.

FIG. 7 is a perspective view of a second rough shot of a sector coarse material on a first shot by a first rough shot by die casting.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 sector mold 2 sector 3 back block 5 mold support device 6 support plate 7 outer ring 8 inner tapered surface 9 segment 10 upper plate 11 upper die side mold 12 base plate 13 lower die side mold 20 first sector 21 profile surface 21a recess 22 Molten metal material 23 Tread pattern 24 Joint 25 Exhaust hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 30:00 B29L 30:00

Claims (6)

[Claims] 1. A tire vulcanization molding die comprising a plurality of sectors formed by casting and laminating a plurality of shots by die casting to form a molding die by arranging them in a ring shape. A machining allowance for machining a tread pattern is formed on a profile surface of a sector-integrated mold rough material divided into a plurality of shots by die-casting and cast and laminated, and the machining allowance is applied to the machining allowance. A tire vulcanization molding die formed by processing a tread pattern. 2. A tire mold comprising a molding die by mounting a plurality of pieces formed by casting and laminating a plurality of shots by die-casting on a back block and arranging them in an annular shape. A mold for sulfuric acid forming, wherein a machining allowance for machining a tread pattern is formed on a profile surface of a plurality of pieces that are cast and laminated by dividing into a plurality of shots by the die casting, and machining is performed on the machining allowance. Alternatively, a tire vulcanization mold formed by processing a tread pattern by electric discharge machining. 3. The cast rough material or the spliced portion of each piece is formed by solidification shrinkage of a cast metal material.
3. The tire vulcanization mold according to claim 1, wherein a minute gap of 0.005 to 0.06 mm is formed. 4. The tire vulcanization molding die according to claim 1, wherein an exhaust hole communicating with the atmosphere in a normal direction from the back side of the mold is formed on the line of the joint portion. 5. A first shot is formed by die casting in a first split mold to form a sector-integrated mold coarse material having a partially uneven tire profile surface shape, and is melted into a concave portion of the mold coarse material. A second shot of the metal material is used to form a profile surface with a machining allowance for machining a tread pattern, and the first shot and the second shot are
Form a fine gap due to solidification shrinkage of the metal material at the joint of the mold coarse material with the shot, and process the tread pattern by machining or electric discharge machining instead of the profile surface machining allowance. A method for manufacturing a tire vulcanization molding die, wherein an exhaust hole communicating with the atmosphere is formed in a normal direction from a back side of a mold on a joint line. 6. A first shot is formed on a first split mold by die casting to form a split first piece block partially having an uneven tire profile surface shape, and a concave portion of the first piece block. A second shot of the molten metal material to form a profile surface provided with a processing allowance for processing the tread pattern, and solidification shrinkage of the metal material at the joint of the piece block of the first shot and the second shot A fine gap is formed, and a tread pattern is machined by machining or electric discharge machining instead of machining of the profile surface, and communicates with the atmosphere in the normal direction from the back side of the mold on the joint line of the piece block. For producing a tire vulcanization mold having exhaust holes formed therein.