JP2001232644A - Mold for tire vulcanization molding and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for tire vulcanization molding which can improve exhaust efficiency in a tire vulcanization process and save labor in a process for processing/assembling piece blocks and its production method. SOLUTION: In the mold which produces a plurality of pieces by casting/ laminating the piece blocks by shots by die casting and forms one sector integrally by cast-jointing/connecting the pieces, a metal raw material of the preceding shot of the piece block and a metal raw material of the succeeding shot are constituted of different metals, the coefficient of linear expansion of the metal raw material of the succeeding shot is made larger than that of the metal raw material of the preceding shot. The preceding piece block is constituted by mechanical processing, a different kind of metal raw material is shot on the metal raw material of the first piece block constituted by the mechanical processing for cast lamination, and a fine clearance is formed in the cast joint part between the first piece block and the cast/laminated second piece block by the solidification shrinkage of the metal raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for vulcanizing and molding a tire, and more particularly to a method for manufacturing the same. More specifically, a dissimilar metal is used for a first piece block and a second piece block for casting and lamination. Accordingly, the present invention relates to a tire vulcanization molding die capable of improving exhaust efficiency during a tire vulcanization step and further saving labor in a piece block processing / assembly step, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a sector mold used as one of tire vulcanization molding dies is formed by adjoining a plurality of pieces having irregularities corresponding to at least a profile surface of a tread portion of a product tire to each other. Then, one sector is constituted by mounting it on the back block, and a plurality of sectors are interconnected to constitute an annular sector mold.

[0003] During tire vulcanization molding, air stagnation or gas is generated between the outer peripheral surface of the tire and the molding surface of the mold, and the air or gas forms minute recesses on the surface of the product tire to produce a product. It is known to cause defects. For this reason, a through-hole for venting air, called a vent hole, and a groove for exhausting are conventionally formed in the molding surface of the 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) in which a vent hole or an exhaust groove is not formed on a mold 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. The latter invention is formed by casting a dissimilar metal (SS400) into the base metal (aluminum) of the pattern piece and forming it by a difference in linear thermal expansion coefficient at a tire vulcanization molding temperature (160 ° C.). 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, since a dissimilar metal (SS400) is formed by casting, a volume necessary for generating a gap due to a difference in linear thermal expansion coefficient due to the dissimilar metal is required, and a required gap amount is secured at an arbitrary position. It is difficult to remove air from the mold substantially.

SUMMARY OF THE INVENTION It is an object of the present invention to form a gap which can easily form a gap at the time of assembling without performing special processing or intervening members, and form a gap which can secure required exhaust performance at an arbitrary position. It is possible to manufacture tires with good dimensional accuracy and to reduce the occurrence of defective tires during vulcanization molding, to save labor in the processing and assembly process, and to further enhance the exhaust effect. An object of the present invention is to provide a mold for sulfur molding and a method for producing the same.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a tire vulcanization mold according to the present invention. A tire vulcanization molding die manufactured and cast-joined with a plurality of pieces to integrally form one sector, wherein a metal rough material of a preceding shot and a metal rough material of a subsequent shot of the piece block are formed. The gist of the invention is that the material is made of a dissimilar metal.

Further, according to the method of manufacturing a tire vulcanization molding die of the present invention, a plurality of piece blocks are cast and laminated to form a piece, and a fine joint due to solidification shrinkage of a metal material is formed at a joint between the piece blocks. A method for manufacturing a tire vulcanization molding die that forms a large gap, in which a first piece block constituting each pitch and a plurality of pitches is manufactured in advance by casting or machining, and then a spacer is formed through a jig. A second shot molding die and a plurality of first piece blocks are alternately arranged in series corresponding to the length of one sector, and the plurality of first piece blocks are arranged on the second shot molding die. Thereafter, a second shot of a dissimilar metal material having a different linear expansion coefficient from the metal coarse material of the first piece block is produced between the first piece block and the second shot molding die to produce a second piece block, The cure After removing the intermediate spacer while leaving the spacers at both ends from the above, the second shot molding die and the first piece block are respectively disposed in the space between the second piece blocks, and the third shot is performed. After that, the piece blocks are cast-joined, the spacers located at both ends are removed, and then a fourth shot is performed on both end sides of the piece block and the back of the first piece block to perform the piece block for one sector. Is to be connected and fixed.

The present invention is constructed as described above, and the finished product of die casting is integrated with one sector instead of each piece block, thereby making it possible to omit the processing and assembly steps of the piece block. Further, when the first piece block and the second piece block are cast and laminated with the same kind of molten metal material, or when the first piece block and the second piece block are adjacent to each other.
When a piece block is spliced, minute gaps due to solidification and shrinkage of the metal material can be formed at the joints of the piece blocks, so gaps can be easily formed during assembly without special processing or intervening members. Also, by using different kinds of metal as the metal rough material of the first piece block and the second piece block to be cast and laminated, it is possible to improve the exhaust efficiency in the tire vulcanizing step.

[0013]

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

FIG. 1 is a perspective view of one sector 1 constituting a split-type pureeless mold (sector mold) embodying the present invention. FIG. 2 is a first piece mounted on a back block 2 of the sector 1. FIG. 3 shows a cross-sectional view of a piece 3 (made of aluminum), which is composed of a block 3a and a second piece block 3b.

In the one sector 1, as shown in FIG. 1, a plurality of pieces 3 having irregularities 5 corresponding to at least a profile surface of a tread portion of a product tire are mounted on a back block 2 so as to be adjacent to each other. It is constituted by doing.

As shown in FIG. 2, the plurality of pieces 3 mounted on the back block 2 are formed by dividing a tread pattern in the tire circumferential direction into a plurality of sections at a fixed pitch or an arbitrary pitch, and are constituted by a single piece. Each of the pieces is divided into a plurality of shots by die casting and divided into a first piece block 3a and a second piece block 3a.
b.

A fine gap (0.005 to 0.005) due to solidification shrinkage of the metal material is formed in the joint portion X of the metal material (the first piece 3a and the second piece 3b) formed by a plurality of shots.
0.08 mm, preferably 0.02 mm).

Further, an exhaust hole 4 communicating with the minute gap is formed below the profile surface of the piece 3, and an exhaust hole communicating with the atmosphere is provided on the back side of the piece 3 although not shown. It is.

In the first embodiment of the present invention, the finished product of die casting is not made into each piece block, but
By integrating one sector, the processing steps of each first piece block 3a and second piece block 3b are eliminated.

Next, a method for manufacturing a puree mold according to the first embodiment of the present invention will be described with reference to FIGS. 3 (a) and 3 (b).
This will be described with reference to FIGS.

First, as shown in FIGS. 3A and 3B,
First, a first shot casting is manufactured by die-casting the first piece block 3a constituting each pitch and a plurality of pitches by using a first shot mold 13a and using an aluminum material.

Next, as shown in FIG.
A plurality of spacers 15 and 15x and a second shot molding die 13b are alternately arranged in series by a length of one sector S via the first piece block 3 and the first piece blocks 3
a is disposed on the second shot molding die 13b.

Thereafter, as shown in FIG. 5, a second shot is produced between the first piece block 3a and the second shot molding die 13b to produce a second piece block 3b. After removing the intermediate spacer 15 while leaving the spacers 15x at both ends, the second shot forming die 13b and the first shot molding die 13b are inserted into the space between the second piece blocks 3b.
By arranging the piece blocks 3a and performing the third shot, the piece blocks 3a and 3b are jointed and connected, and the spacers 1 located at both ends are further provided.
After removing 5x, a fourth shot P is performed on both ends of the piece blocks 3a and 3b and on the back surface of the first piece block 13a, and as shown in FIGS. 13b is connected and fixed.

Then, from the back surface of the first piece block 3a, on the joint line Xa, 3 to 5 mm from the profile surface W.
The air outlet 16 for air escape is formed in the normal direction.

As described above, by integrating one sector S instead of each piece block in the finished product of die casting, the processing steps and assembly steps of the piece blocks 3a and 3b can be omitted. When the first piece block 3a and the second piece block 3b are cast and laminated with the same kind of molten metal material, or when the adjacent first piece block 3a and second piece block 3b are jointed, the piece blocks 3a and 3b Fine gaps can be formed in the joint X by solidification shrinkage of the metal material. Therefore, gaps can be easily formed during assembly without special processing or intervening members, and the exhaust effect can be enhanced. is there.

Next, according to a second embodiment of the present invention, a piece block 3a manufactured by the first shot when manufacturing the puree mold as described above by duccus casting.
And the metal coarse material of the piece block 3b manufactured in the second shot are made of different metals having different linear expansion coefficients (for example, aluminum (Al) and iron (Fe)), so that X and a slit between each piece block can be formed large, thereby improving the exhaust efficiency in the tire vulcanizing step.

In a specific embodiment of the present invention, the metal coarse material of the second shot has a larger coefficient of linear expansion than the metal rough material of the first shot, and the metal coarse material of the first shot is iron ( The linear thermal expansion coefficient of Fe: 11.8 × 10 ⁻⁶ ), and the metal coarse material of the second shot is made of aluminum (linear thermal expansion coefficient of Al: 23.6).
× 10 ^-6 ).

FIG. 10 (A) shows the case where the metal rough material of the first shot is aluminum (Al), and FIG. 10 (B) shows the case where the metal rough material of the first shot is iron (Fe). 5 compares the size of the slit in FIG.

In the case where the metal coarse material of the first shot shown in FIG. 10A is aluminum (Al), the metal rough material of the first shot previously manufactured by die casting is cooled to room temperature and cooled to 20 ° C. Then, in the second shot, a shot was formed at a melting temperature of 700 ° C. and cast and laminated. When this was cooled at a normal temperature of 20 ° C., aluminum (Al) of the metal rough material in the second shot was changed to a double-sided material as shown in FIG. The joint is solidified and contracted to form a slit.

When the metal rough material of the first shot and the second shot is heated to 200 ° C. during vulcanization, each of the first shot and the second shot has a linear expansion coefficient of aluminum (Al). It expands by a minute, and as a result, becomes smaller than the slit at normal temperature.

On the other hand, when the metal coarse material of the first shot is iron (Fe) and the metal coarse material of the second shot is aluminum (Al) shown in FIG. The first shot metal coarse material is cooled at room temperature and shot at a melting temperature of 20 ° C. in the second shot and cast and laminated at a melting temperature of 700 ° C. When cooled at a normal temperature of 20 ° C., the aluminum shot of the second shot is cooled. In (Al), as shown in the figure, a slit is formed by solidification shrinkage of the joint portion at both ends.

Then, when the metal rough material of the first shot and the second shot is heated to 200 ° C. during the vulcanization, the iron (Fe) of the first shot becomes aluminum (A).
Since the expansion coefficient is smaller than 1), a large slit can be obtained as a result.

As described above, the size of the slit at the time of vulcanization is remarkably different between the case where the same kind of metal is cast and the case where the dissimilar metal is cast. When a material such as iron (Fe) having a smaller expansion coefficient than aluminum (Al) is used, the gap (slit) at the joint can be increased, thereby reducing the exhaust efficiency during the tire vulcanization process. Therefore, the casting pressure of the second shot can be increased to increase the product accuracy.

The dissimilar metal of the first shot is not particularly limited to iron (Fe) as in the above embodiment as long as it has a smaller expansion coefficient than aluminum (Al) as the second shot metal coarse material. . When aluminum (Al) is used as the second shot metal rough, aluminum (A) is used as the first shot metal rough.
l) It is necessary to use a material having a smaller expansion coefficient.

[0035]

According to the present invention, as described above, the first piece blocks constituting each pitch and a plurality of pitches are manufactured in advance by casting or machining, and then the spacer and the second shot forming metal are formed via a jig. And a plurality of first piece blocks are disposed on a second shot molding die alternately in series with each other so as to correspond to a length of one sector. A second shot of a dissimilar metal material having a different linear expansion coefficient from the metal coarse material of the first piece block between the first and second shot molding dies to produce a second piece block; After removing the intermediate spacer while leaving the spacer, the second shot forming die and the first piece block are respectively disposed in the space between the second piece blocks, and the third shot is performed. each Since the base blocks are cast-joined and the spacers located at both ends are further removed, the fourth shot is performed on both end sides of the piece blocks and the back of the first piece block to connect and fix the piece blocks for one sector. The following excellent effects can be obtained. (a). A gap can be easily formed at the time of assembling without special processing or intervening members. (b) A tire having good appearance and high dimensional accuracy can be manufactured by forming a gap at an arbitrary position to secure required exhaust performance. (c). The occurrence of defective tires during vulcanization molding can be reduced. (d). Labor saving in the processing / assembly process (work) can be achieved. (e). Since the joint line is provided between the pitches, the exhaust effect can be enhanced. (f). By using dissimilar metals for the metal coarse material of the first piece block and the second piece block to be cast and laminated, it is possible to improve the exhaust efficiency during the tire vulcanization process, and thus to improve the second shot. Product accuracy can be increased by increasing the casting pressure.

[Brief description of the drawings]

FIG. 1 is a perspective view of one sector constituting a split-type purees mold (sector mold) embodying the present invention.

FIG. 2 is a cross-sectional view of a piece including a first piece block and a second piece block mounted on a back block of a sector.

FIGS. 3 (a) and 3 (b) are one process diagram of a method for manufacturing a tire vulcanization molding die, and FIG. ) Is AA of (a)
It is arrow sectional drawing.

FIGS. 4A and 4B are two process diagrams of a method for manufacturing a tire vulcanization molding die. FIG. 4A shows a second shot die and spacers alternately arranged to perform a second shot. Sectional view of the process,
(B) is a sectional view taken along the line BB of (a).

FIG. 5 is an explanatory view of a step of removing a spacer at an intermediate portion while leaving spacers at both ends, and performing a second shot for the second time on that portion.

FIG. 6 is an explanatory view of a step of removing a spacer at both ends and performing a third second shot on both end sides of the piece block and the back surface of the first piece block.

FIG. 7 is a cross-sectional view of a completed piece block for one sector, showing a process in which an exhaust hole for air escape is formed on the casting line from the back surface of the first piece block.

FIG. 8 is a side view of FIG. 7;

FIG. 9 is a bottom view as viewed in the direction of arrows CC in FIG. 7;

FIG. 10A is a process diagram showing a slit forming state at the time of vulcanization in the case where the first and second shots are made of the same kind of metal coarse material, and FIG. 10B is a first shot. It is explanatory drawing which compared the process figure which shows the shaping | molding state of the slit at the time of vulcanization at the time of vulcanization when the metal coarse material of the 2nd shot is the same kind of metal.

[Explanation of symbols]

Reference Signs List 1 sector 2 back block 3a first piece block 3b second piece block 3 piece 4 exhaust hole 5 unevenness 13a first shot mold 13b second shot molding mold 14 jig 15 pacer 16 exhaust hole for air escape

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI theme coat テ ー マ (reference) B29L 30:00 B29L 30:00 F term (reference) 4F202 AA45 AH20 AJ02 CA21 CB01 CU14 4F203 AA45 AH20 AJ02 DA11 DB01 DC01 DL10

Claims (5)

[Claims] 1. A tire vulcanization molding in which a plurality of pieces are manufactured by casting and laminating piece blocks formed by a plurality of shots by duskast casting, and the plurality of pieces are connected by seam joint to form one sector integrally. A mold for vulcanizing a tire, wherein the metal rough material of the first shot and the metal rough material of the subsequent shot of the piece block are composed of different metals. 2. The method according to claim 1, wherein the metal rough of the previous shot is
The tire vulcanization molding die according to claim 1, wherein a metal coarse material of a subsequent shot has a large linear expansion coefficient. 3. The above-mentioned piece block is formed by machining, and a different kind of metal coarse material is shot and cast and laminated on the metal coarse material of the first piece block formed by this machining to form a first piece block. The tire vulcanization molding die according to claim 1 or 2, wherein a minute gap is formed in a joint portion between the metal material and the second piece block formed by casting and lamination. 4. An exhaust hole for escaping air in a normal direction, leaving 3 to 5 mm from a profile surface on a casting line from a back surface of the first piece block.
Or a mold for vulcanization molding of a tire according to 3. 5. A method for manufacturing a tire vulcanization mold for forming a piece by casting and laminating a plurality of piece blocks, and forming a fine gap due to solidification shrinkage of a metal material at a joint between the piece blocks. Wherein, in advance, a first piece block constituting each pitch and a plurality of pitches is manufactured by casting or machining, and then the spacer and the second shot forming mold are separated by a jig into a length corresponding to one sector. The first piece blocks are arranged alternately in series, and the plurality of first piece blocks are arranged on a second shot molding die.
A second piece block is manufactured by performing a second shot of a dissimilar metal material having a different linear expansion coefficient from the metal rough material of the first piece block between the shot forming mold and a second piece block, and the spacers at both ends are left from the jig. After removing the intermediate spacer by means of the second piece block, the second shot forming die and the first piece block are respectively disposed in the space between the second piece blocks, and the third shot is performed to perform the third shot. After the spacers located at both ends are removed, a fourth shot is performed on both ends of the piece block and the back of the first piece block to connect and fix the piece blocks for one sector. Manufacturing method of mold for sulfur molding.