JP2002079361A - Metallic mold for forming aluminum wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a continuous operation using a metallic mold so as not to develop the seizing and the galling even in the case of repeatedly working an ejector pin. SOLUTION: This metallic mold arranges a cavity in the interval between the lower metallic mold having a sprue hole and a gate part at the center part and the upper metallic mold arranged so as to be faced to the lower metallic mold, and also, is constituted of a gate cut-off pin disposed so as to be freely and vertically slid in the upper metallic mold faced to the gate part, an inside metallic mold disposed so as to be adjoined with the periphery of the gate cut-off pin, an outside metallic mold disposed at the outer periphery of the inside metallic mold and an upper backup mold for holding both of the inside metallic mold and the outside metallic mold. A tapered shape notching part opening the lower end part zone of the inner periphery of the inside metallic mold adjoined with the gate cut-off pin toward the cavity side, is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for forming an aluminum wheel, which enables stable sliding of a gate cutting pin used for cutting and separating a cast product and a biscuit.

[0002]

2. Description of the Related Art FIG. 7 is a longitudinal sectional view of an upper mold, ie, a movable mold, showing an example of a conventional aluminum wheel forming mold.
Is an enlarged view of a main part. In FIG. 7, the upper mold 4 includes an inner mold 42 located inside, and an outer mold (not shown) located on the outer periphery of the inner mold 42. A gate cutting pin 9 is provided at the center of the inner mold 42. Before the molten metal filled in the cavity is solidified, the gate cutting pin 9 is moved downward as indicated by a two-dot chain line to cut and separate the cast product and the biscuit. Reference numeral 8 denotes a gate unit.

[0003]

However, as shown in FIG. 7, a V-shaped cross section is formed at both contact portions of the outer peripheral lower end of the gate cutting pin 9 facing the cavity and the inner peripheral lower end of the inner mold 42. When there is only a small concave portion 80 having a shape, and the molten metal 11 is injected and filled into the cavity 10 and an attempt is made to take out a cooled and solidified casting, the main body of the casting is pushed out by an extrusion pin 86. When the mold was released from the upper mold 4, a part of the cast product inserted into the concave portion 80 was sometimes cut off from the main body and remained in the concave portion 80 as it was. Therefore, when the push pin 86 is repeatedly operated, the solidified portion of the molten metal remaining in the concave portion 80 is baked on the gate cutting pin 9 and generates galling, which makes it impossible to perform stable continuous operation. Was.

An object of the present invention is to provide a die for forming an aluminum wheel having a gate cutting pin which can be continuously operated without causing seizure or galling even when a releasing operation is performed by repeatedly operating an extrusion pin. Is to provide.

[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 an upper mold provided opposite to the lower mold. A gate cutting pin provided in the upper mold so as to be slidable up and down in opposition to the gate portion while providing a cavity between the mold and an inner metal provided adjacent to the periphery of the gate cutting pin; A mold, an outer mold disposed on an outer peripheral portion of the inner mold, and an upper backup mold for holding both the inner mold and the outer mold, and an inner mold adjacent to the gate cutting pin. A tapered cutout opening toward the cavity side was provided in the lower end region of the inner periphery of the mold.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes a lower die or a fixed die, 2 denotes a design die on the upper surface side of the lower die 1, 3 denotes a lower backup die on the lower surface side of the lower die 1, and a tightening bolt 2.
4 and are attached to a lower mold 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. FIG. 1 shows a closed state by the mold clamping device,
The 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, and reference numeral 86 denotes an extrusion pin.

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 mutual misalignment between the design die 2 and the backup die 3. It is possible to do. In addition, a ring-shaped cooling medium passage 12 is provided at an outer peripheral portion near the runner 30 at the bottom of the design mold 2 that is in contact with the lower backup mold 3. 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 die 4 is provided above the lower die 1 so as to face the lower die 1, and is concentric with a gate cutting pin 9 located at the center and an outer peripheral portion 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.

The length of the middle partition plate 56 is
A cooling medium passage 62 is secured between the lower end of the shaft 6 and the vertical hole 52 having the bottom, and has such a length that the cooling medium can flow through a one-time flow. Further, the holding plate 72 has an inverted concave-shaped cooling medium passage 62 therein (FIG. 4).
(2), and a heat-resistant packing (for example, gasket) 71 on the upper and lower portions of the holding plate 72, respectively.
And the lid 74 are arranged so as to overlap with each other.

Here, the present invention will be described with reference to FIGS. As shown in the figure, a large tapered notch 82 having a V-shaped cross section and opening toward the cavity is provided in the lower end region of the inner periphery of the inner mold 42 facing the cavity. Such a notch 82
Has the following advantages. That is, when the molten metal 11 is injected and filled into the cavity 10 and the cooled and solidified casting is to be taken out, the casting is pushed out by the extrusion pin 86 and released from the upper mold 4 when the cutout 82 is formed. Part 84 of the casting inserted into
Is released together with the casting body. For this reason,
The gate cutting pin 9 can be stably operated without baking or galling.

Here, a method for forming an aluminum wheel using a mold having a cooling medium passage according to the present invention will be described.

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

First, when the injection plunger 7 is advanced by the injection cylinder while the mold is clamped and the injection sleeve 6 filled with the molten aluminum 11 is joined to the lower backup die 3, the molten metal 11 is transferred to the injection plunger 7. 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 to cause the pushing pin 86 to act, and the cast product is projected from the upper mold 4. Release. Thus, one cycle of the casting operation is completed.

Aluminum melt 11 into cavity 10
When the casting and filling are completed, the mold is cooled and the aluminum melt 11 filled in the cavity 10 is solidified, but the tip of the copper bar 15 is cooled by the continuous flow of the cooling medium, and the inside of the copper bar 15 is cooled. When the molten metal 11 solidifies due to a temperature gradient and a high heat transfer coefficient, solidification heat and sensible heat are released. In particular, since the amount of heat released from the vicinity of the gate portion 8 and the cavity surface 13 having a cast-out shape is large, it is necessary to make the cooling medium passage 12 close to cool this heat. Mold cracking may occur due to poor adhesion and thermal stress.

For this reason, the lower mold 1 has a cavity surface 13.
A copper rod 15 having a high thermal conductivity and a circular cross section is mounted therein. The cross-sectional shape of the copper rod 15 is not limited to a circular shape, and a cross-sectional shape other than a square, a hexagon, and an octagon can be freely selected.

After the copper rod 15 is first inserted into the hole 16, the copper rod 15 is heated when the molten metal is cast into the cavity 10, and contracts when the mold is cooled after filling the molten metal. . As described above, the copper rod 15 is prevented from sliding down to the cooling medium passage 12 side by the expansion and contraction due to the heating and cooling of the copper rod 15.
The screw is attached to the inner surface of the hole 16 by a close fit, or a screw is formed along the axial surface of the copper rod 15, and the same screw as the copper rod 15 is formed on the inner surface of the hole 16. Is screwed into the hole 16 and can be mounted.

The expansion and contraction of the copper rod 15 by heating and cooling prevents the copper rod 15 from sliding down to the cooling medium passage 12 side. It is important to increase the processing accuracy of the copper rod 15 so that a gap is not formed between the copper rod 15 and the hole 16 as much as possible, and to mount the copper rod 15 so that the copper rod 15 is fitted into the hole 16. By doing so, the heat of the molten metal 11 reaching the hub portion 14 is transmitted to the copper rod 16, transmitted through the copper rod 15 having a high thermal conductivity, and cooled at the portion in contact with the cooling medium (for example, water). Cooling of the part 14 is promoted.

By removing a large amount of heat stored in the hub portion 14 in this manner, adhesion of the release agent to the design mold 2 and thermal stress can be reduced, and the life can be prolonged. The distance at which the tip of the copper rod 15 protrudes may cause a large flow resistance in the cooling medium (generally, water is preferable, but oil or liquid N2 may be used) flowing in the cooling medium passage 12. A position that does not exist is desirable.

On the other hand, if the length of the vertical hole 52 formed in the upper mold 4 is too long and is too close to the cavity 10, the spoke portion is supercooled and the heat is excessively removed, which is not a desirable state. Conversely, if the length of the vertical hole 52 is too short, a large amount of heat stored in the spoke site cannot be removed. Therefore, it is desirable to appropriately determine the length of the vertical hole 52 according to the thickness of the spoke portion of the aluminum wheel.

[0026]

According to the present invention, a cavity is provided between a lower mold having a casting port and a gate portion at the center and an upper mold provided opposite to the lower mold, and the gate is provided. A gate cutting pin disposed slidably up and down on the upper mold in opposition to the portion, an inner mold disposed adjacent to the periphery of the gate cutting pin, and an outer peripheral portion of the inner mold. An outer mold, and an upper backup mold that holds both the inner mold and the outer mold. The inner mold has an inner peripheral lower end region adjacent to the gate cutting pin and is directed toward the cavity. By providing a tapered notch that opens, the cast product inserted into the notch even if it is pushed out with an extrusion pin to release the cast product taken into the upper mold from the upper mold. Part of the mold is securely released together with the casting. Therefore, it is not possible to galling or seizure may occur even if the out gate cutting pin.

[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 in a case where a separate jacket-like 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 showing the present invention.

FIG. 6 is an enlarged view of a main part of FIG. 5;

FIG. 7 is a vertical cross-sectional view of a periphery of a concave portion provided on a lower periphery of a conventional gate cutting pin.

FIG. 8 is an enlarged view of a main part of FIG. 7;

[Explanation of symbols]

 REFERENCE SIGNS LIST 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 section 9 Gate cutting pin 10 Cavity 11 Aluminum melt 12 Coolant passage 12c Cooling medium direct passage 13 Cavity surface 14 Hub part 15 Copper rod 16 Hole 22 Depression 23 Lid 24 Tightening bolt 30 Runner 42 Inner die 43 Engagement part 44 Outer die 45 Step 52 52 Vertical hole 56 Middle partition plate 58 Upper part Backup type 60 Jacket 62 Ring-shaped cooling medium passage 64 Cooling medium passage 66 Cooling medium inlet 68 Partition plate 70 Locking member 71 Heat resistant packing 72 Holding plate 74 Cover 80 Depression 82 Cutout 84 Part of casting 86 Extrusion pin

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 a cavity is provided opposite to the gate portion. A gate cutting pin slidably arranged in the upper mold vertically, an inner mold arranged adjacent to the periphery of the gate cutting pin, and an outer mold arranged on the outer periphery of the inner mold And an upper backup mold that holds both the inner mold and the outer mold, and has a tapered shape that opens toward the cavity side at an inner peripheral lower end region of the inner mold adjacent to the gate cutting pin. A die for forming an aluminum wheel, which is provided with a notch.