JP2002079357A - Metallic mold for forming aluminum wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic mold for forming an aluminum wheel with which even in the case that tension stress caused by a repeated heat cycle is applied on a part having a sharp angle, heat crack is not developed on the metallic mold. SOLUTION: In the metallic mold for forming the aluminum wheel, a cavity is arranged in the interval between the lower metallic mold having a gate part for casting molten metal at the center part and the upper metallic mold arranged so as to be faced with the lower metallic mold, and the lower metallic mold is vertically divided into two parts and constituted of a design mold faced with the cavity at the upper surface side and a lower backup mold at the lower surface side of the design mold. Then, the design mold is divided into two parts of the inner side and the outer side at the position having a corner part sharply curved in the cavity surface of the design mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die for forming an aluminum wheel, which prevents cracks from being generated on the die surface due to repeated heat cycles.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional mold for forming an aluminum wheel in which a design die is integrally formed. Generally, a mold for forming an aluminum wheel has an integrated structure which is advantageous in manufacturing cost. Often produced. In the figure, reference numeral 1 denotes a lower mold having a vertical molten metal passage in the center, that is, a fixed mold,
Is an upper die, that is, a movable die, 5 is a slide core mounted on the upper die 4 so as to be slidable in the horizontal direction, and 6 is an injection sleeve mounted on a lower central portion of the lower die 2 with its tip inserted. Reference numeral 7 denotes an injection plunger slidably disposed in an injection sleeve 6, reference numeral 8 denotes a gate portion, reference numeral 9 denotes a gate cutting pin mounted on the upper mold 4, reference numeral 10 denotes a cavity, and a molten metal 11 is cast into the cavity 10. Rarely molded products were cast aluminum wheels.

[0003]

However, in a series of casting cycles such as hot water supply → solidification → mold release → spray → hot water supply, an integrated structure having a sharply curved corner portion like the Y portion shown in FIG. When the mold is used repeatedly, a tensile stress and a compressive stress act on the Y portion due to expansion and contraction due to the heat cycle, and cracks are generated on the mold surface, resulting in a problem that the life of the mold is shortened.

An object of the present invention is to provide a mold for forming an aluminum wheel, which does not cause a heat crack in the mold even when a tensile stress accompanied by a repeated heat cycle is generated at a surface portion of the mold with a sharp angle. Is to do.

[0005]

According to the present invention, there is provided a lower mold having a gate portion for casting a molten metal at a central portion, and a lower mold provided opposite to the lower mold. A mold for forming an aluminum wheel, comprising a design mold provided with a cavity between a mold and a lower mold divided into upper and lower parts and facing a cavity on an upper surface side and a lower backup mold on a lower surface side of the design mold. The design mold was divided into two parts, an inside part and an outside part, at a location having a sharply curved corner on the cavity surface of the design part.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is a lower mold or a fixed mold,
Reference numeral 2 denotes a design die on the upper surface side of the lower die 1, and reference numeral 3 denotes a backup die on the lower surface side of the lower die 1, which are connected by tightening bolts 24. Reference numeral 2 denotes a design type of the lower die 1, and 3 denotes a backup type, which is connected by a tightening bolt 24 and is attached to a lower die holder and a fixed platen (not shown).

An upper mold 4 and a slide core 5 of the upper mold 4 are mounted on an upper mold holder and a movable platen. 6
Denotes an injection sleeve, 7 denotes an injection plunger, and 8 denotes a gate. This figure shows the closed state by the mold clamping device.
A cavity 10 in the shape of an aluminum wheel is formed between the lower mold 1, the upper mold 4 and the slide core 5.
Reference numeral 11 denotes a molten aluminum alloy which is filled into the cavity 10 by the injection plunger 7.

The lower backup die 3 has a cylindrical concave portion 22 at the center, and the design die 2 is fitted on the lower backup die 3 to prevent misalignment between the design die 2 and the lower backup die 3. It is possible to do. In addition, a runner 30 at the bottom of the design mold 2 that comes into contact with the lower backup mold 3.
A ring-shaped cooling medium passage 12 is provided at an outer peripheral portion close to. The passage 12 is formed by combining a ring-shaped groove provided on the lower surface side of the design mold 2 with the upper surface of the backup mold 3, and is formed between the ring-shaped cooling medium passage 12 and the outer periphery of the fixed mold 1. The cooling medium linear passage 12c communicates with the cooling medium.

The cooling medium linear passage 12c is composed of two lines. One cooling medium linear passage 12c is provided with a cooling medium inlet, and the other cooling medium linear passage 12c is provided with a cooling medium outlet. Reference numeral 68 denotes a partition plate for forming a flow path for the cooling medium such that the cooling medium introduced from the cooling medium inlet passes through the predetermined path, is discharged from the cooling medium outlet via the cooling medium linear path 12c. . A lid 23 is welded to the design mold 2 on the lower backup mold 3 side of the cooling medium passage 12 so that the cooling medium does not leak outside.

On the other hand, the upper mold 4 is provided above the lower mold 1 in opposition to the lower mold 1, and has a gate cutting pin 9 located at the center and a concentric circle on the outer periphery of the gate cutting pin 9. The inner mold 42 is provided in the shape of
The outer mold 44 is provided concentrically around the outer periphery of the outer mold 44. The inner mold 42 and the outer mold 4 including these gate cutting pins 9
4 and an upper backup type 58 that holds both of them.

Next, as a means for cooling the upper mold 4, a cooling medium passage 62 is directly formed in the upper mold 4 itself.
As shown in FIGS. 3 and 4, there is a case where a separate jacket having the cooling medium passage 62 is provided without directly engraving the cooling medium passage 62 in the upper mold 4. Will be described.

First, the inner diameter side of the outer mold 44 is cut into the shape of a step 45, and a jacket 60 having a ring-shaped cooling medium passage 62 is provided directly on the step 45. In this case, the engaging portion 4 in which the outer peripheral portion of the inner mold 42 is formed in a stepped shape.
3, the engaging portion 43 is configured to be engaged with the inner peripheral step of the outer mold 44 so that the inner mold 42 does not drop. A vertical hole 52 extending in a direction corresponding to the spoke portion of the aluminum wheel is formed in the outer mold 44 on the cooling medium passage 62.

A partition plate 68 is provided so that the inlet 66 of the cooling medium passage 62 and the outlet 64 of the cooling medium passage 62 determine the flowing direction of the cooling medium in the 180-degree direction. In addition, a middle partition plate 56 is arranged at the center of each of the eight vertical holes 52 having the bottomed portions, and the inside of the cooling medium passage 46 can be continuously circulated through the middle partition plate 56 by a one-time flow. ing.

As shown in FIG. 4A, an intermediate partition plate 56 is inserted into the center of the vertical hole 52 so as to divide it into two while contacting the wall surface of the vertical hole 52 having the bottom.
The upper end of the middle partition plate 56 is attached to the lifting member 70 in a T-shape by welding or the like. This is because the partitioning plate 56 is
2, both ends of the lifting member 70 are connected to the outer mold 44.
In order to prevent the locking member 70 from shifting downward. Further, the length of the middle partition plate 56 is such that the cooling medium passage 62 is secured between the lower end portion of the middle partition plate 56 and the vertical hole 52 having the bottom, and the cooling medium can flow through a one-way flow. It is length. Further, the holding plate 72 has an inverted concave cooling medium passage 62 (FIG. 4 (2)) inside, and heat-resistant packings (for example, gaskets) are provided on the upper and lower portions of the holding plate 72, respectively.
The cover 74 is disposed so as to overlap with the cover 71.

Here, the structure of the split mold when the design mold 2 of the present invention is divided into two will be described. As shown in FIG. 1, the design mold 2 has an inner design mold 7 having a gate portion 8 at the center.
6 and an outer design mold 78 arranged on the outer periphery of the inner design mold 76. The inner design mold 76 and the outer design mold 78 are divided into two parts, and the two are combined in a stepped shape at a step portion 80, and the outer design mold 78 is divided into the inner design mold 76 and the inner design mold 76. When placed on the upper part, as shown in FIG. 5, both dies 76 and 78 can be combined in a form having a joint at the Y portion, and both dies 76 and 78 can be combined. Has a structure in which positioning is performed by stopping pins (not shown) so that the phases do not deviate from each other.

When forming an aluminum wheel using the design mold 2 thus divided into two parts, hot water supply → solidification → release →
A large tensile stress acts on the Y portion of the design mold 2 shown in FIG. 5 by expansion and contraction due to the heat cycle due to a series of casting cycles of spraying → hot water supply, and these stresses repeatedly act. Cracks occur, and eventually the cracks gradually progress, making the design mold 2 unusable. In particular, in the case of the design mold 2, if a crack occurs on the surface, the crack is transferred to an aluminum wheel product, which may be a defective product.

In order to prevent such cracks on the mold surface, the tensile stress generated at the corners of the mold (for example, the Y portion in FIG. 5) during the heat cycle described above is dispersed or the tensile stress is reduced. It is necessary to have a structure that does not occur. For this reason, in the present invention, in a place having a corner portion having a sharp curve as shown in FIG. 1, the design mold 2 is divided into two parts inside and outside near the corner part,
The purpose is to prevent tensile stress from being generated.

Here, a method for forming an aluminum wheel using a design die having a sharply curved corner portion according to the present invention will be described.

In the cavity 10, the molten aluminum 11
After the injection and filling, during a series of casting and molding operations from cooling of the mold to removal of the casting, the lower mold 1 uses a cooling medium (for example, water) introduced from a cooling medium inlet.
The cooling medium is continuously circulated from the cooling medium inlet through the cooling medium direct passage 12c, and the cooling medium is also circulated through the cooling medium passage 62.
One-time flow is generated through.

First, when the injection plunger 7 is advanced by the injection cylinder in a state where the mold is clamped and the injection sleeve 6 in which the molten aluminum 11 has been injected is joined to the lower back-up die 3, the molten metal 11 is injected. And cast into the cavity 10 to cast an aluminum wheel material. After the cast product is cut by the gate cutting pin 9 at the gate portion 8 of the lower mold 1, the upper mold 4 is moved upward and an extrusion pin (not shown) is operated to remove the cast product from the upper mold 4. Protrude and release. Thus, one cycle of the casting operation is completed.

[0021]

According to the present invention, when a design mold having sharply curved corners is used, even if tensile stress due to repeated expansion and contraction derived from a heat cycle acts, the tensile stress is eliminated due to division, The occurrence of heat cracks can be prevented. In particular, in squeeze casting, when molding aluminum wheels by a casting method that does not use squeeze casting, molds that mold the design surface side of aluminum wheels, rib-shaped shapes or sharply curved corners In the case where a mold having such a shape is used, a split mold is effective.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a plan view of the upper mold cut along AA in FIG.

FIG. 3 is a development view of a cooling medium passage in a case where a separate jacket-shaped cooling medium passage is provided in an outer mold.

FIG. 4A is a longitudinal sectional view taken along line BB of FIG. 3;
FIG. 4B is a vertical cross-sectional view taken along line CC of FIG.

FIG. 5 is a longitudinal sectional view of a main part of the present invention.

FIG. 6 is a longitudinal sectional view of a conventional aluminum wheel molding die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower mold (fixed mold) 2 Design mold 3 Lower backup mold 4 Upper mold (movable mold) 5 Slide core 6 Injection sleeve 7 Injection plunger 8 Gate part 9 Gate cutting pin 10 Cavity 11 Molten metal 12 Cooling medium passage 12c Cooling medium direct passage 13 Cavity surface 14 Hub part 15 Copper rod 16 Hole 22 Recess 23 Lid 24 Tightening bolt 30 Runner 42 Inner mold 43 Engagement unit 44 Outer mold 45 Step 60 Jacket 64 Cooling medium outlet 66 Cooling medium Inlet 52 Vertical hole 56 Middle partition plate 58 Upper backup type 62 Ring-shaped cooling medium passage 68 Partition plate 70 Locking member 71 Heat resistant packing 74 Lid 76 Internal design type 78 External design type

Claims (1)

[Claims] 1. A cavity is provided between a lower mold having a gate portion for casting a molten metal at a central portion and an upper mold provided opposite to the lower mold, and the lower mold is divided into upper and lower parts. An aluminum wheel molding die comprising a design die facing the cavity on the upper surface side and a lower backup die on the lower surface side of the design die, and having a corner portion which sharply curves on the cavity surface of the design die. A mold for forming an aluminum wheel, wherein the design mold is divided into two parts, an inner part and an outer part.