JP2820860B2 - Tire mold and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a tire made of an aluminum alloy and a method for producing the same.

[0002]

2. Description of the Related Art Generally, tire molding dies are shown in FIGS.
A mold 1 made of gypsum or the like divided as shown in FIG. 1 is arranged in a circle on a circular platen 2, and a circular casting frame 3 and a feeder frame 4 are erected on its outer and inner circumferences. It is manufactured by casting a molten aluminum alloy. Also, as shown in FIG. 3 (a diagram showing the tire molding surface) and FIG. 4 (a diagram showing the tire molding surface of the mold), the tire molding surface of the manufactured mold has a comparative shape called a rib 5 or a lug 6. A projection called a bone 8 for forming a wide groove, and a sipe 7
There is a thin projection called a blade 9 for forming a narrower groove called this. The blade 9 is often formed of an iron-based material such as stainless steel because the strength of the blade 9 is insufficient with an aluminum alloy serving as a mold base material.

[0003] The bone portion 8 of the tire molding die is shown in FIG.
As shown in FIG. 5, the groove of the mold 1 is filled with an aluminum alloy. Also, blade 9
As shown in FIG. 6, the part to be cast in the mold base material is projected from the surface of the mold 1, the necessary shape part is set in a state of being wrapped inside the mold 1, and the casting is performed to determine the exact position. It is fixed to.

However, in recent years, the design of the tire design surface has become more complicated, and the ribs 5 and lugs 6 have become thinner and finer. In particular, the bones 8 formed of an aluminum alloy are deformed during tire molding due to insufficient strength. The problem of breakage or breakage has been occurring. In order to improve the strength of the bone portion 8, the bone portion 8 may be made of an iron-based material like the blade 9, but unlike the blade 9, the bone portion 8 may be made of an iron-based material. There was a problem that the cost was too high. If a rigid body made of iron is used up to the bone portion 8, the balance between the solidification shrinkage and heat shrinkage of the aluminum alloy during casting and the solidification shrinkage and heat shrinkage on the mold side is lost, and the dimensional accuracy of the mold is reduced. There were problems such as difficulty in maintenance.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and prevents the bone from being deformed or broken during tire molding by strengthening the bone simply and at low cost. The purpose of the present invention is to provide a tire molding die and a method of manufacturing the same.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a tire molding die according to the present invention is provided in a required portion of a molding surface bone of a tire molding die made of an aluminum alloy. A core material having a higher modulus of longitudinal elasticity and a higher yield strength than the base material is cast without being exposed on the surface . The method of manufacturing a mold for tire molding according to the present invention is characterized in that a taper pin made of a material that does not melt or deform during casting of an aluminum alloy is set in a groove portion of a mold, and a longitudinal elastic coefficient and a yield strength are higher at the tip than a mold base material. The core material is cast into a necessary portion of a molding surface bone by inserting a core material having a high thickness, extracting a taper pin from a mold after casting an aluminum alloy, and then casting the core material at a necessary portion of a molding surface bone portion.

[0007]

There are two types of molds for forming tires, a vertical split type as shown in FIG. 7 and an upper and lower integrated type as shown in FIG. 8, in which rubber used as a tire is formed inside these molds.
Vulcanize and then release. If an excessive load is applied to the bones or blades of the tire molding die during this molding or release, deformation or breakage is caused. In particular, in the case of the vertical split type, a larger load acts on the bone and the blade.

However, in the tire molding die of the present invention,
A core material with a higher modulus of longitudinal elasticity than the mold base material is cast in the required part of the molding surface bone without exposing it to the surface, so it acts on the tire molding die when molding and releasing the tire Most of the load to be applied can be borne by the core material. Moreover, since the yield strength of the core material is higher than that of aluminum as the mold base material, permanent deformation of the bone of the mold during tire molding or mold release can be reliably prevented. The least expensive material that can withstand the casting of an aluminum alloy for this purpose is an iron-based material. Practically, it is preferable to use a JIS female screw from the viewpoint that it can correspond to various dimensions, has good adhesion and bonding properties to an aluminum alloy, and is easily available.

According to the method for manufacturing a tire molding die of the present invention, a tire molding die in which the above-mentioned core material is cast can be easily manufactured. Examples will be described in detail.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to manufacture a tire molding die of the present invention,
First, as shown in FIG. 9, in the groove of the mold 1 made of gypsum or the like,
A taper pin 10 made of a material such as iron that does not melt or deform during casting of an aluminum alloy is set in a state where the tip end on the small diameter side is projected. For this purpose, a method of implanting in a rubber mold for producing the mold 1 and inverting the mold 1 or a method of driving the taper pin 10 into the mold 1 can be employed. It is preferable that a release agent such as carbon is applied to the surface of the tapered pin 10.

Next, after the mold 1 is arranged in a circle on the circular platen 2 as shown in FIG. 10, the tip of the tapered pin 10 has a lower longitudinal elastic modulus and yield strength than an aluminum alloy as a mold base material. The high core material 11 is fitted. As described above, it is preferable to use a JIS female screw as the core material 11, and a hole 12 into which the taper pin 10 is to be inserted is formed at the front end thereof.

In this manner, all the core members 11 are tapered.
After fitting into the tip of the mold 10, as shown in FIG.
And a feeder frame 4 are erected, and a molten aluminum alloy is poured and cast. The part shown by the two-dot chain line in FIG. 11 is a mold product part to be a tire molding mold. This makes the core material
11 is embedded in the bone of the tire molding die without exposing its surface.

After casting, only the taper pin 10 is removed from the mold as shown in FIG. Then, as shown in FIG.
Is filled with a taper pin 13 made of an aluminum alloy of the same material as the mold material created as a master, and the mold and the taper pin 13 are spot-welded from the surface. Then, if the surface is finished with a file or the like, it is possible to obtain a tire molding die in which the core material 11 is accurately cast in necessary portions of the molding surface bone as shown in FIG. In addition, it is desirable that the volume ratio of the core material 11 to the bone part is a necessary minimum, for example, 30% or less.
This is to prevent the core 11 from constraining the solidification shrinkage and thermal expansion of the bone after casting, thereby preventing the finished dimensions from being adversely affected.

FIG. 15 is a view showing a specific example of the arrangement of the core material 11 in the molding surface bone of the tire molding die, which is disposed in the bone near the parting line of the die. This tire molding die is a vertical split type, and the inner diameter of the die is
1340mm, the height of the bone is 25mm. And taper pin 10
JIS B1352 taper pin class 1 3 × 40, S45C was used, and JIS B1177 hexagon socket set screw flat tip, M8 × 40, S45C was used as the core material 11. The number of cores 11 is 200 per one set of tire molding dies. If the core material 11 is not cast-in, the bone part is broken or deformed at the time of tire molding or mold release, but the bone part is broken by the core material 11 as described above. No deformation or deformation, continuous use is possible.

[0015]

As described above, in the tire molding die of the present invention, a core material having a higher modulus of longitudinal elasticity and a higher yield strength than the base material of the die is exposed on the surface of the required portion of the molding surface. Don't let me
The mold can be cast in a safe condition to prevent bone breakage and deformation during tire molding and mold release, and there is no exposure of the core material to the mold surface. The surface condition can be maintained without generating irregularities around the cast-in portion even when the method is performed. In addition, the method of manufacturing a tire molding die of the present invention is described above in comparison with a method of drilling a hole in a die frame after casting, embedding a core material, and rebuilding with an aluminum alloy. There is an advantage that a tire mold can be easily and inexpensively manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a mold is being arranged in a ring.

FIG. 2 is a cross-sectional view of a state in which a molten metal is poured after a mold ring arrangement.

FIG. 3 is a front view of a profile surface of the tire.

FIG. 4 is a front view of a profile surface of a tire molding die corresponding to FIG.

FIG. 5 is a cross-sectional view showing a state where a molten metal is being filled into a groove of a tire molding die.

FIG. 6 is a cross-sectional view showing a state of a cast-in portion and a mold-containing portion of a blade.

FIG. 7 is a perspective view showing an upper and lower split type tire molding die.

FIG. 8 is a perspective view showing a vertically integrated type tire molding die.

FIG. 9 is a cross-sectional view showing a state where a taper pin is driven into a mold.

FIG. 10 is a cross-sectional view showing a state where a core material is set on a tapered pin.

FIG. 11 is a cross-sectional view showing a state where the core material is being cast-in.

FIG. 12 is a cross-sectional view showing a state in which a taper pin is extracted from a cast tire molding die.

FIG. 13 is a cross-sectional view showing a state in which a common material is buried in a hole after a taper pin is extracted.

FIG. 14 is a sectional view showing a tire molding die according to the present invention.

15A and 15B are a plan view and a cross-sectional view illustrating an arrangement position of a core material according to the embodiment.

[Explanation of symbols]

 1 mold, 8 bones, 10 taper pins, 11 cores

Claims (2)

(57) [Claims] 1. A state in which a core material having a higher modulus of longitudinal elasticity and a higher yield strength than a base material of a mold is not exposed to a required portion of a molding surface bone of a mold for molding a tire made of an aluminum alloy.
A mold for molding a tire, characterized by being cast in the mold. 2. The aluminum alloy is melted and deformed during casting.
Insert a taper pin of a material that does not
Core material with higher longitudinal elastic modulus and yield strength than the mold base material at the end
After casting the aluminum alloy,
By removing the papin, the core material can be molded
Of a mold for molding tires,
Manufacturing method.