JPH0647161B2 - Vacuuming device for hot chamber die casting machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot chamber die casting machine in which a sleeve for injecting a molten metal into a cavity formed in a mold is arranged in the molten metal of a melting pot. so,
It is often used for die casting of zinc alloy, tin alloy and lead alloy.

[Prior Art] Conventionally, a generally used hot chamber die casting machine stores molten metal in a melting pot, arranges a sleeve in the melt of the melting pot, and inserts the sleeve through a hot water supply passage. The molten metal supplied to the inside is pressurized with a plunger tip, and the pressurized molten metal is injected into a cavity through a gooseneck passage of a gooseneck, a gooseneck tip, a nozzle, and a runner formed in a mold.

Further, as a vacuum drawing device in a so-called vacuum die casting method in which air or gas in the cavities is previously sucked at the time of injection, a method in which the entire mold is sealed with a hood (Nellmore type), a sealed ejector box is used. Evacuate the vacuum pressure in the ejector box to evacuate the inside of the cavity through the air vent hole that is formed in the movable mold (Oze type, Cax type), open and close the passage in the vacuum runner carved on the mold dividing surface. There is a method (Molton type) in which a cut-off pin is provided and the cavities are evacuated via a vacuum runner.

The hot chamber die casting machine described above and the various vacuum evacuation methods described above are specified in "Die casting technician handbook" edited by the Federation of Kinkoku Die Casting Industrial Cooperatives.

[Problems to be Solved by the Invention] The vacuuming device in such a conventional hot chamber die casting machine has the following problems to be solved.

In the Nelmore type that seals the entire mold with a hood, the ose type that has an ejector box, and the cax type, it is necessary to set the pressure of the chamber with a large volume equivalent to the mold in advance to the vacuum pressure. Degree for a short time (several seconds)
In order to increase the vacuum pressure, it is necessary to increase the pumping capacity of the vacuum pump, which is not preferable because the equipment becomes large, and the airtightness of the chamber must be completely maintained to obtain the vacuum pressure. For this reason, a sealing member for maintaining airtightness is required. Furthermore, the hood and the chamber of the ejector box under vacuum pressure and the cavities must be communicated with each other through a vacuum drawing passage (air vent hole). Since it is necessary to provide a new passage for the conventional mold, the conventional mold cannot be used as it is.

Also, in the Molton type, it is necessary to provide a vacuum runner, which is not preferable because the mold is enlarged due to the placement of the vacuum runner and the cross-sectional area of the vacuum runner gate is restricted. After that, it is necessary to cut the runner portion that has flowed into the vacuum runner by post-treatment, which is not preferable because it wastes material and increases the number of cutting steps.

[Means for Solving the Problems] The present invention has been made in view of the above problems, and it is an object of the present invention to provide a hot chamber die casting machine capable of vacuum casting without any modification to a conventional die. In order to achieve the purpose, a sleeve is placed in the melt of the melting pot, and the molten metal to be supplied into the sleeve through the hot water supply passage is pressurized by the plunger tip, and the mold is inserted through the gooseneck passage, the gooseneck tip and the nozzle. In the hot chamber die casting machine that injects the molten metal into the cavity of the, from the end of the mold clamping process to before the start of the injection process by the plunger tip, the control valve connects the vacuum drawing passage and the nozzle that communicate with the vacuum source. , The gooseneck passage and the vacuum evacuation passage, and the gooseneck passage and the nozzle are shut off to evacuate the inside of the cavitation. It

[Embodiment] An embodiment of the evacuation device in the hot chamber die casting machine according to the present invention will be described below with reference to FIG.

Reference numeral 1 denotes a machine base, in which a fixed die plate 2 is fixedly arranged on the right side of the base surface 1A, and a movable die plate 3 faces the fixed die plate 2 and has a movable surface.
It is movably arranged on A.

Hydraulic pressure is often used as a power source for moving the movable die plate 3.

The fixed die 4 is fixedly attached to the fixed die plate 2, while the movable die 5 is fixedly attached to the movable die plate 3, and is movable with the mating surface 4A of the fixed die 4. A cavity T is formed between the molds 4 and 5 in a state where the mating surface 5A of the mold 5 is clamped and abutted, and one end of the runner 6 is opened in the cavity T and the other part of the runner 6 is opened. The end opens to the right end surface of the fixed mold 4.

Reference numeral 7 denotes, for example, a melting pot in which molten zinc alloy is stored, and the temperature of the molten metal in the melting pot 7 is controlled within a certain temperature range by a heat insulation furnace 8 surrounding the melting pot 7.

Reference numeral 9 denotes a cylindrical sleeve that reaches a position below the molten metal surface AA of the melting pot 7, and the gooseneck 1 extends from below the sleeve 9 to a position above the molten metal surface AA.
0 extends, and a gooseneck passage 11 is formed in the gooseneck 10 as a part of the injection passage. One end of the gooseneck passage 11 is connected to the bottom portion of the sleeve 9 located below the molten metal surface AA, and the other end opens to the upper end portion of the gooseneck 10 located above the molten metal surface AA.

Further, one end of the hot water supply passage 12 opens at a position below the molten metal surface AA of the sleeve 9 and the other end of the hot water supply passage 12 is located below the molten metal surface AA. Connected within 7. The molten metal below the molten metal surface AA inside the sleeve 9 and inside the melting pot 7 is connected by this hot water supply passage 12.

A plunger tip 13 that pressurizes the inside of the sleeve 9 is movably arranged in the sleeve 9, and the plunger tip 13 is operated by an injection cylinder 14.

In addition, the open end portion 11A of the gooseneck passage 11 of the gooseneck 10 that opens above the molten metal surface AA.
And the open end 6 of the runner 6 opening to the right side of the fixed mold 4.
A is communicated with A by sandwiching a gooseneck tip 15 and a nozzle 16 each having a passage therein from the gooseneck passage 11 side.

That is, the bottom portion of the sleeve 9 has the gooseneck passage 1
1, passage 15A of gooseneck tip 15, nozzle 1
6, the cavitation T is communicated via the runway 6.

The above is a conventionally known hot chamber die casting machine, and the vacuuming device in the hot chamber die casting machine according to the present invention is added with the following configuration in order to achieve the above object.

20 is a passage 15A that can be bored inside the gooseneck 15.
It is a cylindrical valve hole that intersects with the valve hole 20, and a control valve 21 that moves in the valve hole 20 is arranged in the valve hole 20.

The control valve 21 has a gooseneck tip 1 at its outer circumference 21A.
A vacuum evacuation passage 22 connected to a vacuum source (not shown) is opened in the outer periphery 21B of the control valve 21 that faces the nozzle 16 while controlling the opening and closing of the passage 15A of No. 5.

The passage opening / closing operation of the control valve 21 will be described in more detail. When the control valve 21 is below the valve hole 20 (shown in FIG. 1), the passage 15A of the gooseneck tip 15 is located at the outer periphery 21A of the control valve 21. The evacuation passage 22 that is closed and opens at the outer periphery 21B facing the nozzle 16 of the control valve 21 at this time opens to the passage 15B on the nozzle 16 side of the gooseneck tip 15.

On the other hand, when the control valve 21 moves to a position above the valve hole 20,
Since the outer periphery 21A of the control valve 21 is disengaged from the passage 15A of the gooseneck tip 15, the passage 15B of the gooseneck tip 15 is opened and the opening of the vacuum suction passage 22 to the outer periphery 21B of the control valve 21 is closed by the valve hole 20. To be done.

Reference numeral 23 is a hydraulic cylinder that applies the above operation to the control valve 21.

Next, the casting operation will be described in the order of steps.

The first step ... (Start) ... The movable mold 5 shown in FIG. 2 is located apart from the fixed mold 4, and the control valve 21
Is in the lower position of the valve hole 20 and the plunger tip 13 is in the upper position of the sleeve 9.

According to this, the molten metal in the melting pot 7 flows into the sleeve 9 and the gooseneck passage 11 from the hot water supply passage 12, and enters the sleeve 9 and the gooseneck passage 11 at the same level as the molten metal surface AA in the melting pot 7. The molten metal of is stored.

The vacuum evacuation passage 22 formed in the control valve 21 opens into the passage 15B on the nozzle 16 side of the gooseneck tip 15 and communicates with the nozzle 16 so that the gooseneck passage 11
Is cut off from the nozzle 16 by the outer circumference 21A of the control valve 21 and is cut off from the vacuum passage 22.

2nd step ... (Clamping and vacuuming start) .. The movable die 5 shown in FIG. 3 is moved to bring the mating surface 5A of the movable die 5 into contact with the mating surface 4A of the fixed die 4, Cavitation T between molds
Is formed, and then a vacuum is drawn from the vacuum drawing passage 22.

According to this, in the cavitation T, the runner 6, the nozzle 16,
The pressure is reduced through the passage 15B on the nozzle 16 side of the gooseneck tip 15, and the cavitation T including these passages is reduced to a vacuum state.

3rd step ... (vacuum evacuation is completed) ... Move the control valve 21 shown in FIG. 4 upward by the hydraulic cylinder 23,
The control valve 21 is arranged outside the passages 15A and 15B of the gooseneck tip 15.

According to this, the vacuum suction passage 22 is closed by the valve hole 20, and the vacuum suction passage 22 includes the passages 15A and 15B of the gooseneck tip 15, the nozzle 16 and the gooseneck passage 1.
Blocked with 1.

On the other hand, the passage 1 on the nozzle 16 side of the gooseneck tip 15
5B communicates with the passage 15A, and the gooseneck passage 11,
The passages 15A and 15B of the gooseneck tip 15 and the nozzle 16 communicate with each other.

Thus, the gooseneck passage 11 above the melt, the passages 15A and 15B of the gooseneck tip 15, the nozzle 1
6, the runner 6, and the cavity T are in a vacuum state.

Fourth step ... (Injection) ... The plunger tip 13 shown in FIG. 5 is moved downward in the sleeve 9 by the injection cylinder 14 to compress the inside of the sleeve 9, and the pressurized molten metal causes the gooseneck passage 11, The gooseneck tip 15 is injected into the cavitation T through the passages 15A and 15B, the nozzle 16 and the runner 6.

Fifth step (solidification) ... While the molds 4 and 5 shown in FIG. 6 are tightened, the plunger tip 13 is returned to the upper position by the injection cylinder 14 and the solidification time is maintained.

According to this, the molten metal in the cavity T and the runner 6 cools and solidifies, while the nozzle 16 and the gooseneck tip 1
The molten metal in the passages 15A and 15B of No. 5 and the gooseneck passage 11 is sucked toward the sleeve 9 by the plunger tip 13 returning to increase the volume in the sleeve 9 and decrease the pressure in the sleeve 9, and the hot water supply passage The molten metal in the melting pot 7 is sucked from 12 and the molten metal level AA of the molten metal in the melting pot 7 is formed again in the gooseneck passage 11 and the sleeve 9.

The return of the molten metal in the nozzle 16 to the gooseneck passage 11 side is achieved by the nozzle 16 being heated by a burner (not shown) and the molten metal not solidifying.

6th step ... (Opening the mold, taking out the product) .. Separate the movable mold 5 shown in FIG. 7 from the fixed mold 4.

According to this, the product formed by solidifying along the shape of the cavity T moves together with the movable mold 5 and moves to the fixed mold 4.
Then, the product is taken out from the movable mold 5.

With the above, one cycle of casting is completed.

The shape of the control valve shown in this embodiment is not limited in any way. The vacuum suction passage communicating with the vacuum source and the nozzle are communicated with each other, and the gooseneck passage and the vacuum suction passage and the gooseneck passage and the nozzle are shut off from each other. Anything can be done.

[Effects of the Invention] According to the vacuuming device in the hot chamber die casting machine of the present invention described above, the following effects are obtained.

(1) Since there is no modification or addition to the conventional mold, such as vacuum runners and cut-off pins, the mold used in the past can be used as it is. Can be done

(2) Since it is not necessary to provide a vacuum runner and a cut-off pin on the mold, it is possible to prevent the mold from becoming large and to increase the material economy and the number of man-hours because the gate cutting work of the vacuum runner does not occur. Instead, it is possible to perform inexpensive vacuum casting.

(3) By arranging the control valve on the gooseneck tip, since the molten metal does not solidify in the passage inside the gooseneck tip, the operation of the control valve can be performed extremely smoothly, and during maintenance of the control valve. Also, since the gooseneck tip can be simply removed without removing the die from the die plate, the maintenance work is extremely easy.

(4) When evacuating the cavity, the water (release agent) remaining in the cavity is sucked into the vacuum passage through the nozzle, but the nozzle is always heated by the burner and is in a high temperature state. Therefore, the moisture can be efficiently discharged from the evacuation passage in the completely evaporated state, and the moisture in the mold can be completely removed.

Thus, the appearance quality of the product can be greatly improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of an evacuation device in a hot chamber die casting machine according to the present invention,
2 to 7 are operation diagrams for each work process. 4 …… Fixed mold 5 …… Movable mold T …… Cavity 6 …… Runway 7 …… Melting pot 9 …… Sleeve 10 …… Gooseneck 11 …… Gooseneck passage 12 …… Hot water supply passage 13 …… Plunger tip 15 ... Gooseneck tip 16 ... Nozzle 20 ... Valve hole 21 ... Control valve 22 ... Vacuum suction passage

Claims (1)

[Claims] 1. A sleeve is arranged in the melt of a melting pot, and the melt supplied to the sleeve through a hot water supply passage is pressurized with a plunger tip to form a mold through a gooseneck passage, a gooseneck tip and a nozzle. In a hot chamber die casting machine that injects molten metal into the formed cavities, a control valve opens a vacuum passage and a nozzle connected to a vacuum source between the end of the mold clamping process and the start of the injection process by the plunger tip. A vacuum evacuation device in a hot chamber die casting machine which communicates with each other and blocks the gooseneck passage and the vacuum evacuation passage, and the gooseneck passage and the nozzle to evacuate the inside of the cavities.