JP2002079362A - Metallic mold for forming aluminum wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic mold for forming aluminum wheel disposing a gas venting passage so that the gas venting is fully performed, and a space part assisting the gas venting while preventing the penetration of molten metal at the tip end part of the gas venting passage faced to the cavity side. SOLUTION: This metallic mold arranges a cavity in the interval between the lower metallic mold having a gate part for casting molten metal at the central part of it and the upper metallic mold faced to the lower metallic mold, and is constituted of a gate cut-off pin disposed so as to be freely and vertically slid to the upper metallic mold faced to the gate part, an inner side metallic mold disposed so as to be adjoined with the periphery of the gate cut-off pin, an ejector pin arranged in the inner side metallic mold and ejecting off the product stuck to the upper metallic mold, an outer side metallic mold disposed at the outer peripheral part of the inner side metallic mold and an upper backup mold for holding both of the inner side metallic mold and the outer side metallic mold. Further, an exhausting passage for left gas for exhausting the left gas in the cavity according as the filling of the molten metal into the cavity, from the gas venting passage arranged between the inner side metallic mold and the outer side metallic mold through the gas venting passage arranged between the inner side metallic mold and the ejecting pin, 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 is provided with a passage for extracting a residual gas in a cavity which is discharged when the cavity is filled with a molten metal.

[0002]

2. Description of the Related Art FIG. 9 is a vertical sectional view of a part of a conventional aluminum wheel molding die, and FIG. 10 is a plan view taken along line FF of FIG. In FIG. 9, the upper mold 4 includes an inner mold 42 located inside, and an outer mold 44 located on the outer periphery of the inner mold 42. In addition, a gate cutting pin 9 is provided at the center of the inner mold 42, and the aluminum wheel product taken into the upper mold when the upper and lower molds are opened around the gate cutting pin 9 is released. For this purpose, extrusion pins 76 are arranged on the inner mold 42 at regular intervals on a constant pitch circle.

Further, between the outer peripheral surface of the inner mold 42 and the inner peripheral surface of the outer mold 44, gas remaining in the cavity 10 due to the casting and filling of the molten aluminum into the cavity 10 is discharged outside the mold. A minute circular gap (gas vent passage) 78 is provided for smooth discharge.

[0004]

However, there is a problem that there is no basic data for determining the size of the gap 78. That is, if the gap 78 shown in FIG. 10 is enlarged, the gas (air) in the cavity 10 can escape well, but when the molten aluminum 11 is filled into the cavity 10, the molten metal 11 enters the gap 78, and finally, The molten metal 1 that has entered the gap 78 when the filled molten metal 11 has solidified
1 also solidifies together. For this reason, since the molten metal 11 at the time of molding of the previous cycle remains solidified at the time of molding of the next cycle, outgassing is incomplete, and these gases are mixed into aluminum wheel products, resulting in a product yield. There was a problem such as a decline.

Conversely, if the gap 78 is reduced, the gas (air) in the cavity 10 is difficult to escape, and when filling the cavity 10 with the molten metal 11, the gas is not sufficiently discharged to the outside of the mold and the residual gas is removed from the aluminum wheel. There is a problem in that it is mixed in the product and the product yield is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a space for assisting gas venting while preventing molten metal from being inserted into the gas venting passage for completely venting gas and the distal end of the gas venting passage facing the cavity. An object of the present invention is to provide a mold for forming an aluminum wheel in which parts are arranged.

[0007]

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 extrusion pin disposed on the inner mold and pushing out a product adhered to the upper mold, an outer mold disposed on an outer peripheral portion of the inner mold, and both the inner mold and the outer mold. And an upper backup mold that holds the inner mold.The gas remaining in the cavity along with the filling of the molten metal into the cavity is supplied to the inner mold through a gas vent passage provided between the inner mold and the outer mold. Through a gas vent passage provided between the pushing pin and the pushing pin. Provided an extraction passage of the residual gas is discharged to the upper mold externally.

[0008]

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, and 3 denotes a lower backup die on the lower surface side of the lower die 1, which are connected by a tightening bolt 24. , Not shown, but attached to a lower mold holder or a fixed platen.

Reference numeral 4 denotes an upper die, and 5 denotes a slide core of the upper die 4, which is mounted on an upper die holder or a movable platen. Reference numeral 6 denotes an injection sleeve, 7 denotes an injection plunger, and 8 denotes a gate. FIG. 1 shows a state in which the mold is closed by a mold clamping device, and reference numeral 10 denotes a lower mold 1, an upper mold 4, and a slide core 5.
Cavity 1 in the shape of an aluminum wheel formed between
0. Reference numeral 11 denotes a molten metal, such as an aluminum alloy, which is cast and filled in 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 backup die 3. I am getting it. Further, a ring-shaped cooling medium passage 12 is provided on the outer peripheral portion near the runner 30 at the bottom of the design mold 2 that comes into 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 and the upper surface of the lower backup mold 3, and is formed between the ring-shaped cooling medium passage 12 and the outer periphery of the fixed mold 1. It is communicated by a perforated cooling medium straight passage 12c.

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 so as to face the lower mold 1, and has a gate cutting pin 9 located at a central portion and an outer peripheral portion of the gate cutting pin 9. An inner mold 42 is provided concentrically, and the inner mold 42 is
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. A gas vent passage between the slide core 5 and the outer mold 44 and the upper backup mold 58 for discharging residual gas in the cavity 10 to the outside of the mold when the molten aluminum is cast into the cavity 10. 1
00 is provided. Reference numeral 94 denotes a portion to be a rim of the aluminum wheel.

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 in the shape of a step 45, and a jacket 60 having a ring-shaped cooling medium passage 62 is directly provided in 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 flow 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, a partitioning 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 recessed cooling medium passage 62 therein (FIG. 4 (2)), 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.

Next, a description will be given of the structure of a gas vent passage for smoothly discharging gas (air) remaining in the cavity 10 to the outside of the mold when the cavity 10 is filled with the molten aluminum 11. First, as shown in FIG. 6, in order to provide a gas vent passage 80 between the outer peripheral surface of the inner mold 42 and the inner peripheral surface of the outer mold 44, the outer periphery of the inner mold 42 is partially engraved. In addition to a polygon (here, for example, an octagon), a non-carved portion, a contact portion 9 between the outer peripheral surface of the inner mold 42 and the inner peripheral surface of the outer mold 44.
2 has no gas vent passage 80 (FIG. 8).

Further, as shown in FIG. 7, the lower end of the gas vent passage 80 facing the cavity 10 is
A front cross section of the lower end outer peripheral surface portion 86 of the second 2 forms a tapered space portion 90 opened to the cavity 10 side. This is because the gas remaining in the cavity 10 is smoothly discharged to the outside of the mold by filling the molten metal 11, and the tapered shape allows the gas to be discharged smoothly and simultaneously the molten metal 11 This is to prevent solidification in the part 90 and intrusion into the gas vent passage 80.

As shown in FIG. 5, reference numerals 80, 82 and 84 are degassing passages, and the gas remaining in the cavity 10 is removed from the space 90 → the gas venting passage 80 → the gas venting passage 82 → the gas venting passage 84. Through the outside of the mold. The gas vent passage 84 is a gap disposed between the push-out pin 76 and the inner mold 42 and the upper vap-up mold. A structure is provided with a minute gap between the inner mold 42 and the extrusion pin 76 for sliding.

If a gas venting passage is provided in the cavity 10 so that the residual gas in the cavity 10 can be smoothly discharged, the molten metal 11 is inserted into the gap between the extrusion pin 76 and the inner mold 42.
This prevents the push-out pin 76 from moving up and down and cannot perform the original function of pushing out the product if the material enters and solidifies as it is. The gas vent passage 82 is a lateral gas vent passage connecting the upper end of the gas vent passage 80 and the lower end of the gas vent passage 84.

Here, a method of forming an aluminum wheel using the metal mold for forming an aluminum wheel of the present invention will be described.

The molten aluminum 11 is placed in the cavity 10.
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 circulated continuously from the cooling medium outlet through the cooling medium direct passage 12c throughout, and a one-time flow is generated in the vertical hole 52 through the middle partition plate 56.

First, when the injection plunger 7 is advanced by the injection cylinder while the mold is clamped and the injection sleeve 6 in which the molten aluminum 11 is injected is joined to the lower backup mold 3, the molten aluminum 11 is injected. 7 and cast and filled into the cavity 10. At this time, the molten aluminum is poured into the cavity 10.
Most of the gas remaining in the cavity 10 is discharged from the degassing passage 100 at the initial stage of casting and filling the inside, but after the filling of the rim portion 94 with the molten aluminum is completed, The remaining gas is sequentially discharged to the outside of the mold as a gas a flowing through the gas vent passage 80, a gas b flowing through the gas vent passage 82, and a gas c flowing through the gas vent passage 84.

The molten aluminum 11 is placed in the cavity 10.
When the filling of the molten metal is completed and most of the residual gas is discharged out of the mold, the molten metal 11 is inserted into the space 90, so that the subsequent gas release becomes impossible. When the casting and filling of the molten metal 10 into the cavity 10 is completed, the upper and lower dies 1 and 4 are cooled, and the molten metal 11 is solidified to cast an aluminum wheel material casting. The cast product is cut by the gate cutting pin 9 at the gate portion 8 of the lower mold 1, and is taken out of the upper mold 4.

Aluminum melt 11 into cavity 10
When the filling is completed, the mold is cooled and the molten metal 11 filled in the cavity 10 is solidified, but the tip of the copper rod 15 is cooled by the continuous flow of the cooling medium, and the copper rod 15 is cooled.
When the molten metal 11 is solidified by a high heat transfer coefficient due to a temperature gradient inside, a solidified swirl 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, the cooling medium passage 1 is used to cool this heat.
However, if it is too close, it may be cooled too much, causing poor adhesion of the release agent and mold cracking due to 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 means of interference, 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 bar 15 by heating and cooling prevents the copper bar 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 attach the copper rod 15 to the hole 16 so that the copper rod 15 is swallowed. 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 end of the copper rod 15 protrudes causes a large flow resistance in the cooling medium (generally, water is preferable, but oil or liquid nitrogen 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 heat is excessively removed, which is not a desirable state. Conversely, if the length of the pit 52 is too short, a large amount of heat stored in the spoke site will not 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.

[0031]

According to the present invention, a cavity is provided between a lower mold having a gate for casting a molten metal at the center and an upper mold provided opposite to the lower mold, and the gate is provided in the gate. A gate cutting pin disposed to be slidable up and down on the upper mold in opposition, 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 gas remaining in the cavity along with the filling of the cavity with the molten metal is supplied to the inner mold and the outer mold. By providing a discharge path for residual gas discharged from the gas release passage provided between the molds to the outside of the mold through a gas release passage provided between the inner mold and the extrusion pin, the molten metal can be melted. Degassing is completed before being inserted into the degassing passage Because that can be done, the yield of the casting is greatly improved.

[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 concave-shaped cooling medium passage is formed 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 path diagram of a gas vent passage showing a main part of the present invention.

FIG. 6 is a cross-sectional view taken along line BB of FIG. 1;

FIG. 7 is a sectional view taken along line DD in FIG. 6;

FIG. 8 is a sectional view taken along line EE in FIG. 6;

FIG. 9 is a vertical cross-sectional view showing a gas vent passage remaining in a conventional cavity.

FIG. 10 is a plan view seen from FF in FIG. 9;

[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 Depression 23 Lid 24 Tightening bolt 30 Runner 42 Inner mold 43 Engagement unit 44 Outer mold 45 Step 52 52 Vertical hole 56 Middle partition plate 58 Upper backup Mold 60 Jacket 62 Ring-shaped cooling medium passage 64 Cooling medium outlet 66 Cooling medium inlet 68 Partition plate 70 Locking member 71 Heat resistant packing 72 Retaining plate 74 Cover 76 Extruding pin 78 Gap 80, 82, 84 Gas vent passage 86 Inside Outer peripheral part of lower end of mold 90 Space part 92 Contact part 94 Rim part 100 Gas release Passage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29C 45/34 B29C 45/34 45/38 45/38 C 45/40 45/40

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 on the upper mold vertically, an inner mold arranged adjacent to the periphery of the gate cutting pin, and a product attached to the inner mold and attached to the upper mold And an upper die for holding both the inner die and the outer die. The cavity is filled with molten metal. The gas remaining in the cavity along with the upper mold is removed from a gas vent passage provided between the inner mold and the outer mold via a gas vent passage provided between the inner mold and the extrusion pin. That a passage for extracting residual gas discharged to the outside was provided. Characteristic mold for forming aluminum wheels.