JPS588942B2 - Youto Tanzou Okonaiur Die Casting Kanagata Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an invention in which a die casting machine can be used for making molten metal.

Die casting is an excellent casting method in which the mold cavity in a mold clamping device is filled with molten metal at high speed and high pressure.

In order to fill the mold cavity with molten metal, the molten metal is sent through a casting device such as a mold runner and a thin gate through a plunger tip in a pouring sleeve, so it is difficult to avoid air entrainment. Casting defects inevitably occur.

In addition, even if molten metal is pressurized by a plunger tip to prevent casting defects, there is a so-called gate between the pouring sleeve and the metal cavity, which causes rapid solidification and reduces the pressurizing effect by half. Shrinkage cavities occur in the thick part of the product.

In order to overcome these difficulties, the Acurad method has been proposed in which the gate is widened to effect directional solidification of the molten metal, but it has not been sufficiently effective.

On the other hand, the molten metal casting method is an excellent method for manufacturing defect-free products, but it has the drawback of requiring a dedicated hydraulic press.

The object of the present invention is to manufacture a defect-free product using a die-casting machine, and to use the die-casting machine as is to perform molten metal molding.

The purpose of this is that the tip of the plunger tip of the die-casting machine forms part of the product shape, and the sleeve for the high-pressure cylinder for molten metal is fixed to the movable mold and located at a distance from the mold cavity. This is achieved by a die-casting mold device in which the tip of the pressurizing core inside the sleeve protrudes from the sleeve and can slide to the mold cavity, and a pool is formed below the sleeve and the pressurizing core. be done.

That is, by making the tip of the plunger tip match the shape of the product and manufacturing the mold so that the entire surface of the tip comes into contact with the molten metal, pressure filling with molten metal can be performed using the injection device and the plunger.

In addition, when pressurized filling is performed, the difficulty that product dimensions vary due to fluctuations in the amount of poured metal is solved by a pressurizing core that slides within the sleeve for the high-pressure cylinder.

That is, the pressurizing core, which operates at an adjustable ultra-high pressure of, for example, 500 kg/crti or less, participates in forming the molten metal and holds the molten metal under pressure.

Since the sleeve guiding the pressurized core extends into contact with, preferably close to, the mold cavity, a sump is created between the sleeve and the mold cavity in which excess molten metal solidifies.

That is, since the variation in the cast weight solidifies outside the pressure sleeve, when the mold and pressure sleeve are moved together when the mold is opened, the movement is not obstructed by an extra solidified portion.

By using such a plunger tip and pressurized core, molten metal production can be easily achieved within the same time as the casting cycle of a normal die casting method.

The reliability of the cast products produced by this casting device is high.

In addition, since molten metal can be made using a die-casting machine without using a special hydraulic press, the fields of application of molten metal making are wide.
It is considered to be.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a conceptual diagram showing a specific example of a mold device according to the present invention.

A fixed die 2 is attached to a fixed platen 1 of a die-casting machine, and a movable die 4 is attached to a movable platen 3.

Furthermore, a sleeve 5 for a high-pressure cylinder is fixed to the movable mold 4.

The sleeve 5 is integrated with the movable mold 4 and forms a mold matching surface between it and the fixed mold 2.

The fixed mold 2 and the movable mold 4 are brought together by a mold clamping device (not shown).

In the case of Fig. 1, the core 14 is of the fixed type 2 and the moving type 4.
The movable mold 4 is further provided with a push-out pin 15 for ejecting the product, which is biased by a spring 16 and moved by a hydraulic cylinder 22.

A sleeve 13 having a spout 16 is fitted into the fixed mold 2, and a plunger tip 7 connected to the tip of a suitable rod 9 is slidably disposed within the sleeve 13.

The rod 9 is connected to the injection cylinder 8 and is given a motion similar to a normal plunger tip of a die casting machine.

At the forward limit of the injection cylinder 8, the tip of the plunger tip 7 reaches the same level as the fixed mold 1.

Since the tip of the plunger tip constitutes a part of the product shape, a part of the mold cavity is formed by the plunger tip.

Sleeve 5 for the high-pressure cylinder fixed on the movable mold 4
The pressurizing core 10 is arranged so as to be slidable.

Since the tip of the fixed sleeve 5 is slightly separated from the mold cavity of the product shape, a pool 11 is formed below the fixed sleeve.

The pressurizing core 10 is in contact with the sleeve 5 with a gap of, for example, 0.15 mm, and can be displaced to the point where its tip protrudes from the sleeve 5.

Therefore, when the plunger tip 7 is advanced to the same level as the fixed mold and the pressure core 10 is lowered to a point where the sleeve 5 also protrudes, the plunger tip and the pressure core form part of the product shape.

The operation of the die-casting metal device described above is basically the same as that of the die-casting method, and is carried out as follows.

First, the pressurizing core 10 is displaced and advanced to the mold cavity position of the product shape.

The pressurizing core 10 is locked by a mold stopper or other means.

Molten metal is then placed in the sleeve 13 and pushed into the mold cavity by the plunger tip 7.

Since the amount of molten metal injected is slightly larger than the required amount of the product, the plunger tip 7 completes filling the mold cavity and excess wall portion 11 without reaching the specified advance limit, and a predetermined casting pressure PA is generated in the molten metal. .

Here, the surface area of the pressurizing core 100 is assumed to be 81, and the piston surface area of the hydraulic cylinder 17 for operating the pressurizing core is S2.

In this state, the pressure core 10 is connected to P1 and S from the hydraulic mechanism.
I am receiving two powers.

In order to advance the plunger tip 7 to the specified advance limit, the relationship between the force PAXS1 that tries to push back the pressure core 10 and the force P1 x 82 that holds the pressure core in the initial position is P
When P1 is selected to an appropriate value so that AS1-P1S2, the pressurizing core 10 retreats from the surface defining the mold cavity, and the molten metal in the mold cavity flows into an additional pool between the sleeve 5 and the mold cavity. It forms a part and becomes a part of the extra wall part 11.

Since the pressurized state of plunger tip 1 is maintained, the casting itself is molded under pressure.

However, the casting pressure is slightly lower than that of PA at this stage.

When the plunger tip 7 advances to a predetermined position, the surface that contacts the plunger tip is formed into a predetermined shape.

When the plunger tip 7 reaches its forward limit, a pressure P2 higher than the pressure PA is applied to the pressurizing core 10.

When the pressure P2 is applied to the pressure core 10, the tip of the pressure core 10 protrudes from the lower end of the sleeve 5 and descends while compensating for the solidification shrinkage of the casting, so the final molten metal forging is performed at this stage. .

Then, the plunger tip 9 and the pressurizing core 10 are moved back, and then the movable mold 4 is moved and the product 6 is taken out by the ejecting pin 15.

Incidentally, if the amount of filling into the excess wall portion 11 increases and the pressurizing core 10 no longer protrudes from the lower end of the sleeve 5', the metal wall portion 11 will obstruct product removal.

In order to prevent this, an auxiliary core having the same function as the pressure core 10 can be provided.

In this case, it is preferable not to provide a sleeve for guiding the auxiliary core, but to use a cavity space on the parting surface of the mold.

In addition, the tip of the pressure core 10 is made into a product shape, and the sleeve 1
3 may have an extra wall portion.

In this case, the sleeve 5 may extend into the mold cavity.

Next, a specific example of a hydraulic circuit for operating the pressurizing core 10 will be explained in the second section.
This will be explained using figures.

The hydraulic circuit of the hydraulic cylinder 17 that operates the pressurizing core 10 includes a motor M, a pump P, a high pressure IJ IJ valve 18, a low pressure IJ IJ valve 19, a 2-port position switching valve 20, and a fixed throttle 21. .

When applying pressure P1 to the piston surface of the hydraulic cylinder 17, that is, when retracting the pressurizing core 10 to generate an additional pool after filling the mold cavity, the low pressure IJ IJ-F valve 19 is activated. Activate.

Next, when applying the high pressure P2 to the pressure core 10 for forming molten metal, the low pressure circuit is cut off by the switching valve 20 so that only the high pressure relief valve 18 is operated.

According to the present invention, the following effects are achieved.

(1) Molten metal production can be performed in the same cycle as the die casting method without making any major improvements to the die casting machine.

(2) Fluctuations in the amount of molten metal replenished can be absorbed by the excess wall portion, and products with constant dimensions can be obtained regardless of fluctuations in the amount of molten metal replenished.

(3) Since the sleeve that guides the pressure core is integrated, a constant gap is maintained between the pressure core and the sleeve without being affected by mold deformation due to mold clamping.

Therefore, the sliding resistance during pressurization of the molten metal is small (the pressurizing force is effectively transmitted to the molten metal by the pressurizing core).

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a die casting mold apparatus according to the present invention, and FIG. 2 is a hydraulic circuit diagram. 1...Fixed plate, 2...Fixed type, 3...
...Movable plate, 4...Movable type, 5...
・High pressure cylinder sleeve, 7...Plunger tip, 8...Injection cylinder, 9...
Rod, 10... Pressure core, 11...
Hot water reservoir part or extra flesh part, 13...Sleeve, 17
...Hydraulic cylinder, 18...High pressure cylinder, 19゜゜゛゜゜Low pressure cylinder, 20...
Switching valve, 21... Throttle.

Claims (1)

[Claims] 1 Movable and fixed molds that define the casting cavity,
and a die casting machine comprising a plunger for feeding molten metal into the cavity, wherein the tip of the plunger tip forms part of the product shape, a sleeve for a high pressure cylinder for forming the molten metal is fixed to the movable mold, and A die-casting mold device capable of forming molten metal, characterized in that the pressurizing core in the sleeve is disposed at a position apart from the cavity, and its tip protrudes from the sleeve and is slidable up to the cavity.