JPS5932230B2 - die casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a die casting device with an improved plunger for injecting molten metal.

In die-casting equipment, when the molten metal supplied inside the cylinder is injected by the plunger, the plunger tip attached to the tip of the plunger receives a thermal shock from the molten metal, and as a result, the plunger tip is deformed, distorted, or cracked due to thermal stress. resulting in damage.

In particular, the temperature of molten metal of high melting point materials such as cast iron and steel is high, so a large thermal shock is applied to the plunger tip.
Significant damage to plunger tip.

Therefore, in order to prevent damage to the plunger tip, various improvements have been attempted in terms of materials and structure.
None of them were satisfactory, and die casting using molten metal of high melting point material was difficult.

The present invention has been made in view of the above-mentioned circumstances, and provides a die-casting device that is capable of die-casting high-melting point materials using a split plunger tip with improved thermal shock resistance.

Embodiments of the present invention illustrated in the drawings will be described below.

Figures 1 and 2 show one embodiment, and in the figures, 1 is a device main body including a fixed die, a movable die, etc., 2 is a cylinder, and 3 is a device that is reciprocated within the cylinder 2 by a reciprocating drive device (not shown). The plunger 4°5.6 is a split plunger tip attached to the tip of the plunger 3, 7 is a tapping hole formed in the cylinder 2, and 8 is a cavity provided in the main body 1 of the device.

The split plunger tips 4 to 6 are formed of ceramic such as silicon nitride, aluminum nitride, silicon-aluminum oxynitride, silicon carbide, boron carbide, etc., and are disk-shaped with appropriate diameter and thickness, and Each center portion has mounting holes 4a, 5a, and 6a.

One end of a mounting bolt 9 is screwed into the mounting hole 3a formed at the tip of the plunger 3, and the mounting bolt 9 projects forward from the tip of the plunger 3 along the central axis. It is set up.

Further, the split plunger chips 4 to 6 have mounting holes 4a to 4, respectively.
They are held side by side on the same axis by passing a mounting bolt 9 through the mounting bolts 6a, and are fixed in contact with each other by screwing and tightening a nut 10 to the other end of the mounting bolt 9.

As a result, the divided plunger chips 4 to 6 are combined with each other to form a cylindrical plunger chip, which is attached to the tip of the plunger 3 using a mounting bolt 9 and a nut 10, which are examples of mounting members.

Here, the ceramics forming the split plunger tips 4 to 6, such as silicon nitride, silicon carbide, boron carbide, aluminum nitride, and silicon-aluminum oxynitride, are excellent in terms of strength, low coefficient of thermal expansion, etc., and have high thermal shock resistance. have.

Taking advantage of this property, for example, the composition of silicon nitride is 93 silicon nitride-5 yttria-2 alumina (
wt ratio), the porosity is 0.01 or less, and the thermal expansion coefficient is 2.
7×10', 'C, the thermal shock resistance temperature is 1
It can have high thermal shock resistance of 600°C.

This thermal shock resistance temperature corresponds to, for example, the melting temperature of cast iron, 1550°C.

Therefore, when the molten metal is injected into the cylinder 2 from the injection hole 7 of the cylinder 2, the plunger 3 is moved by the reciprocating drive device.
When moved forward, the divided plunger tips 4 to 6 attached to the tip of the plunger 3 push the molten metal and inject it into the cavity 8.

In this case, the split plunger tips 4 to 6 are subjected to thermal shock by the molten metal.

However, since the plunger chips 4 to 6 are made of ceramic, such as silicon nitride, and have high thermal shock resistance, distortion, deformation, or cracking due to thermal stress associated with thermal shock is less likely to occur.

In addition, the divided plunger chips 4 to 6 have a small length in the axial direction, and the heat received by the molten metal is transmitted and diffused in the circumferential direction of the divided plunger chips 4 to 6, so that the heat distribution is uniform and localized. There are fewer distortions and cracks caused by thermal stress caused by thermal deformation or temperature differences between individual plunger chips.

Therefore, the split plunger tips 4 to 6 can prevent damage caused by thermal shock of molten metal of high melting point materials such as cast iron and steel.
As a result, die casting of high melting point materials, which has been difficult in the past, becomes possible.

Note that the type of ceramic forming the split plunger tip can be selected from various types as required.

Furthermore, the means for attaching the split plunger tip to the plunger is not limited to the embodiments described above.

The die casting apparatus of the present invention can be applied to both a hot chamber method and a cold chamber method, but is particularly effective in a hot chamber method.

As explained above, according to the die-casting device of the present invention, a plurality of divided plunger chips made of ceramic are assembled side by side and attached to the tip of the plunger with a mounting member. In addition to providing thermal shock resistance, the plunger tip is divided into parts for good heat diffusion and uniform heat distribution, which prevents damage to the plunger tip due to thermal shock from high-temperature molten metal. Die-casting is possible.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is a side view showing a split plunger chip in the same embodiment. 1... Device body, 2... Cylinder, 3... Plunger, 4-6... Plunger chip.

Claims (1)

[Claims] 1. A die-casting device characterized in that a plurality of divided plunger chips made of ceramic are arranged and combined on the same axis, and the combined divided plunger chips are attached to the tip of a molten metal injection plunger using a mounting member.