JP3097515B2 - Die casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting machine for forming a casting by pressing a molten metal into a mold at a high speed.

[0002]

2. Description of the Related Art In a general die-casting machine, as shown in Japanese Patent Application Laid-Open No. 5-305410, a plunger tip 2 has a substantially cylindrical shape and a molten metal pressing surface 2f is formed to be flat. As shown in FIG. 2, the surface of the sprue core 4 installed at a position facing the plunger tip 2 is formed into a truncated cone, and the sprue bush 6 is formed on the inclined peripheral surface 4e of the truncated cone. The inclined inner peripheral surface 6n formed at the tip is brought into surface contact.
The upper surface of the truncated cone is the molten metal collision surface 4s of the sprue core 4.

When the molten metal is injected into a plunger sleeve (not shown) and the plunger tip 2 advances in the plunger sleeve and the sprue bush 6 and presses the molten metal, the molten metal is brought into contact with the molten metal collision surface 4 s of the sprue core 4. It collides and is guided to the cavity (not shown) of the mold 1 by the runner 1r. Then, after the cavity is filled with the molten metal, the plunger tip 2 approaches the sprue core 4 to increase the pressure of the molten metal in the cavity, thereby preventing casting defects such as shrinkage cavities when the molten metal solidifies. Is done.

[0004]

Here, a disc-shaped solidified piece formed between the plunger tip 2 and the sprue core 4 is referred to as a biscuit, and the outer surface of the biscuit is an inner wall surface at the tip of the sprue bush 6. Formed by However, since it is structurally difficult to form a cooling water passage at the tip of the sprue bush 6, the cooling capacity of this portion is low. Further, since the surface of the sprue core 4 is formed into a truncated cone and the tip of the sprue bush 6 is in surface contact with the periphery thereof, the outer surface of the biscuit is effective even if the cooling capacity of the sprue core 4 is improved. It is difficult to cool down. For this reason, there is a problem that it takes time to solidify the biscuit, and the cycle time of casting becomes long. The technical problem of the present invention is to improve the cooling capacity by changing the shape of the molten metal collision surface of the sprue core and the shape of the molten metal pressing surface of the plunger tip to minimize the area where the sprue bush contacts the biscuit, thereby improving the cooling capacity and The purpose is to reduce the time required for coagulation.

[0005]

The above-mentioned problems are solved by a die casting machine having the following features. That is,
The die-casting machine according to claim 1 is a cylindrical sprue bush.
A plunger tip that moves forward inside and presses the melt,
Provided at a position facing the plunger tip,
And a sprue core that makes surface contact with the front end of the lub bush.
In a die casting machine, the plunger tip includes:
A molten metal pressing surface protruding from the sprue bush is formed.
The plunger chip is attached to the sprue core.
The concave surface where the molten metal collides with the position facing the molten metal pressing surface
A molten metal collision surface is formed, and the sprue core is
Between the molten metal impact surface and the molten metal pressing surface of the plunger tip
Thus, a biscuit is formed. According to the present invention, since the biscuit is formed by the molten metal collision surface of the sprue core and the molten metal pressing surface of the plunger tip, the biscuit does not contact the sprue bush. In other words, the biscuit is formed by the molten metal collision surface of the sprue core having a high cooling capability and the molten metal pressing surface of the plunger tip without contacting the sprue bush having a low cooling capability, so that the time required for solidifying the biscuit is reduced. You.

According to a second aspect of the present invention, in the die casting machine according to the first aspect, a space is formed inside the sprue core so that the coolant flows along the concave shape of the molten metal collision surface. Have been. For this reason, forced cooling can be performed from the front of the biscuit to the outer peripheral surface,
The cooling capacity is further improved, and the time required for solidifying the biscuit is reduced.

According to a third aspect of the present invention, in the die casting machine according to the first aspect, the shape of the molten metal pressing surface of the plunger tip is a convex shape. Therefore, the contact area of the plunger tip with the biscuit increases, and the rear surface of the biscuit can be effectively cooled by that much. Further, the volume of the space through which the cooling water passes can be increased as compared with the conventional case where the molten metal pressing surface of the plunger tip is formed flat, so that the cooling capacity is further improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a die casting machine according to one embodiment of the present invention will be described with reference to FIG. Here, FIG. 1 is a longitudinal sectional view of a main part of the die casting machine according to the present embodiment. The fixed die 12 of the die casting machine 10 is provided with a sprue bush 22 at a sliding portion of a plunger tip 24. The sprue bush 22 has an inner cylinder 22j.
And an outer cylinder 22t, and a cooling passage 22w for passing cooling water between the inner cylinder 22j and the outer cylinder 22t.
Are formed. Here, the sprue bush 22 is formed so that the inner diameter of the inner cylinder 22j is equal to the inner diameter of a plunger sleeve (not shown).
It is positioned coaxially with the plunger sleeve.

The plunger tip 24 moves from the end of the plunger sleeve to the tip of the sprue bushing 22 so that the molten metal injected into the plunger sleeve can be sprue bush 22 and the runner 16.
r is a member that feeds into a cavity (not shown) via r, and is fixed to the tip of a plunger rod 25 connected to an injection cylinder (not shown). The plunger tip 24 is provided at the tip of the molten metal pressing surface 2.
4k is formed into a convex spherical shape, and a cooling water space 24w having a convex spherical shape for cooling the convex spherical shape molten metal pressing surface 24k substantially uniformly is formed inside. The cooling water space 24w is connected to a cooling water supply passage 25w formed inside the plunger rod 25. That is, the cooling water space 24w corresponds to a space inside the sprue core of the present invention.

The movable die 16 of the die casting machine 10 is provided with a sprue core 26 at a position facing the plunger chip 24. The sprue core 26 is a member that can be replaced when the molten metal is damaged by direct impact or a heat crack occurs due to heat. The molten metal collision surface 26t against which the molten metal collides at the time of casting is formed in a concave spherical shape. A flat end surface 26 is provided around the molten metal collision surface 26t of the sprue core 26.
The flat end face 26y is in surface contact with the tip end face 22x of the sprue bush 22 in a state where the mold is clamped. Here, the diameter of the concave ball-shaped molten metal collision surface 26t is equal to the inner cylinder 22 of the sprue bush 22.
It is set equal to the inner diameter of j. Further, a cooling water space 26w for passing cooling water is formed inside the sprue core 26 so as to surround the molten metal collision surface 26t.

Next, a die casting machine 1 according to the present embodiment.
The operation of 0 will be described. First, a cavity (not shown) is formed in the movable mold 16 and the fixed mold 12 by performing mold clamping. Further, the tip end surface 22x of the sprue bush 22 is a flat end surface 26 of the sprue core 26.
y, the front surface of the sprue bush 22 is closed by the concave spherical molten metal collision surface 26t, and the runner 1 is opened on the side surface of the molten metal collision surface 26t.
The inside of the sprue bush 22 and the plunger sleeve communicate with the cavity by 6r. Further, the cooling passage 22 w of the sprue bush 22, the cooling water space 24 w of the plunger tip 24, and the cooling water space 2 w of the sprue core 26
The minimum required cooling water is supplied to 6w.

When the preparation for casting is completed in this way,
The molten metal is injected into the plunger sleeve to drive the injection cylinder. As a result, the plunger tip 24 moves from the end of the plunger sleeve to the tip of the sprue bush 22, and the molten metal injected into the plunger sleeve is supplied to the cavity via the sprue bush 22 and the runner 16r. You. At this time,
Since the cooling water flowing through the sprue bush 22, the plunger tip 24, and the sprue core 26 is a necessary minimum, the cooling capacity is low and the molten metal supplied to the cavity is hardly solidified.

As described above, when the cavity is filled with the molten metal, the flow rate of the cooling water flowing through the sprue bush 22, the plunger tip 24 and the sprue core 26 increases to a predetermined amount, and the plunger tip 24
Then, the pressure of the molten metal in the cavity is increased. This prevents casting defects such as sinkholes when the molten metal solidifies. Then, as shown in FIG. 1, the convex-shaped molten metal pressing surface 2 of the plunger tip 24.
The plunger tip 24 stops in a state in which 4k projects from the tip surface 22x of the sprue bush 22 and the molten metal solidifies between the molten metal pressing surface 24k of the plunger chip 24 and the molten metal collision surface 26t of the sprue core 26. The biscuit is molded.

As described above, with the molten metal pressing surface 24k of the plunger tip 24 protruding from the tip of the sprue bush 22, all of the molten metal pressing surface 24k of the plunger tip 24 and the molten metal collision surface 26t of the sprue core 26 are disposed. As a result, the sprue bush having a low cooling capacity does not contact the biscuit. Also,
The inside of the sprue core 26 has a concave spherical shaped molten metal collision surface 26t.
Since the cooling water space 26w is formed so that the cooling liquid flows along the sprue 26, the sprue core 26 cools the biscuit from the front surface to the outer surface. Further, a cooling water space 24w having a convex spherical shape for cooling the convex spherical molten metal pressing surface 24k substantially uniformly is formed inside the plunger chip 24. It is cooled strongly by the jar tip 24. For this reason, the time required for solidifying the biscuit can be reduced while maintaining the molten metal replenishing effect by keeping the volume of the biscuit constant, and the cycle time of casting can be shortened.

Although the embodiments of the present invention have been described above, the embodiments of the present invention have the following various technical items in addition to the technical items described in the claims. Please note that. (1) In the die casting machine according to claim 2,
A die casting machine characterized in that a space is formed inside the plunger tip along which the cooling liquid flows along the convex shape of the molten metal pressing surface. Therefore, the cooling capacity of the plunger tip is also improved, and the time required for solidifying the biscuit is reduced. (2) In the die casting machine according to claim 3,
A die casting machine characterized in that the shape of the molten metal collision surface of the sprue core and the shape of the molten metal pressing surface of the plunger tip are set so that the biscuit does not contact the sprue bush.

[0016]

According to the present invention, since the ability to cool the biscuit is improved, the time required for solidifying the biscuit is reduced, and the cycle time of casting is shortened.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a die casting machine according to one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a conventional die casting machine.

[Explanation of symbols]

 12 fixed type 16 movable type 22 sprue bush 24 plunger tip 24k molten metal pressing surface 26 sprue core 26t molten metal collision surface 26w space for cooling water

Claims (3)

(57) [Claims] 1. A molten metal which is advanced in a cylindrical sprue bush.
A plunger tip for pressing the plunger;
The sprue bush is provided at a position facing the
A die casting machine equipped with a sprue core that makes surface contact with the surface.
Thus, the plunger tip includes
A protruding molten metal pressing surface is formed, and the sprue core has a molten metal pressing surface of the plunger tip.
A concave-shaped molten metal where the molten metal collides with the position facing the pressing surface
A collision surface formed between the sprue core and the plunger tip;
A biscuit is formed by the molten metal pressing surface of the die casting machine. 2. The die casting machine according to claim 1, wherein a space through which a cooling liquid flows is formed along the concave shape of the molten metal collision surface inside the sprue core. . 3. The die casting machine according to claim 1, wherein the shape of the molten metal pressing surface of the plunger tip is a convex shape.