JP2743789B2 - Non-porous die casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-porous die casting apparatus used for manufacturing parts in various industrial fields such as hydraulic equipment and automobiles.

[0002]

2. Description of the Related Art Conventionally, in a die casting apparatus, a mold cavity is formed by clamping precise molds including a fixed mold and a movable mold, and the cavity is filled with molten metal and solidified. This is a manufacturing apparatus that can mass-produce castings with high precision and excellent casting surface. The manufacturing process basically includes the following four processes.

(1) A fixed mold and a movable mold are clamped, and molten metal (hereinafter, referred to as molten metal) is poured from a pouring opening.

(2) The molten metal is pushed into the cavity by operating the piston in the sleeve.

(3) The molten metal is solidified.

(4) The fixed mold and the movable mold are opened, and a casting adhered to the movable mold is taken out.

[0007] Of these, (2) and (3) are the most important processes for determining the quality of the casting, but there has been a problem that pinholes and shrinkage cavities have been generated conventionally.

On the other hand, a mold decompression method, a laminar flow filling method,
By introducing a new method such as the local pressurization method, it has become possible to reduce the pinholes and shrinkage cavities generated in the above-mentioned products, thereby achieving a result. For example, in the mold depressurization method, the cavity is evacuated by vacuum evacuation means to improve the flow of the molten metal to prevent pinholes and shrinkage cavities due to the entrainment of gas. The molten metal is made laminar to prevent pinholes and shrinkage cavities due to gas entrapment, and the local pressurization method applies pressure to the part where the molten metal finally solidifies in the cavity. In addition, pinholes and shrinkage cavities are prevented.

[0009]

However, in the above-described local pressurization method, the pressurization is performed after the molten metal in the runner portion solidifies naturally without any special means. It solidifies, leaving pinholes and shrinkage cavities, albeit reduced. Also, the filling rate of the molten metal
If the laminar flow filling method is slow, pinholes and shrinkage cavities are likely to occur in the mold cavity due to poor runoff in the mold cavity. Conversely, if the speed is high, the molten metal will be easily atomized, and the surface will be oxidized and heat treatment will be performed. Even though the hardness increases, the tensile strength does not increase.

The present invention has been made in order to solve the above-mentioned problems, and a die cast capable of producing a cast product in which pinholes and shrinkage cavities are drastically reduced and hardness and tensile strength are improved. It is intended to provide a device.

[0011]

SUMMARY OF THE INVENTION The present invention provides a mold formed by a fixed mold and a movable mold, a vacuum means for evacuating the inside of the mold, and a pressurizing means for pressurizing the inside of the mold. In a non-porous die-casting apparatus which solidifies the molten metal while being pressurized by the in-mold pressurizing means after filling the molten metal into the mold, the forcible connection between the vacuum means and the inside of the die is provided. A non-porous die-cast apparatus comprising: a cooling passage; and a cooling means provided in a runner portion connected to the inside of the mold and cooling the molten metal.

[0012]

The movable mold is moved and clamped with the fixed mold.
Next, inject the molten metal from the pouring port, move the piston,
The molten metal is injected while the inside of the mold is evacuated. Then, the molten metal filled in the mold rises and enters the forced cooling path, where it is cooled and solidified to block the outlet of the molten metal. Further, the runner portion is cooled to rapidly solidify the molten metal, thereby making the inside of the mold airtight. Immediately thereafter, the molten metal filled in the mold is pressurized by the pressurizing means in the mold. When the molten metal solidifies and casting is completed, the movable mold is moved to open the mold, and the casting is removed from the movable mold.

[0013]

FIG. 1 is a schematic configuration of a nonporous die casting apparatus of the present invention, and FIG. 2 is a view taken in the direction of the arrow II in FIG. 1, that is, a schematic configuration of a divided surface on a movable mold side. In FIGS. 1 and 2, 1 is a fixed mold, 1a is a fixed mold cavity, 1b is a fixed mold base, 2 is a movable mold, 2a is a movable mold cavity,
2b is a base of the movable mold, 2c is an insertion hole provided in the base of the movable mold, 2d is an insertion hole provided in the movable mold, 3 is a runner, 4 is a sleeve, 4a is a pouring port, and 5 is a piston. ,
6 is a forced cooling path, 7 is a vacuum suction path, 8 is a cooling water path of the forced cooling path 6, 9 is a pressurizing device, 9a is a cylinder, 9b is a piston, 9c is a squeeze pin, 10 is a cooling water path of the runner 3, 10a Is a cooling water inlet, 10b is a cooling water outlet, 11 is a die base, and P is a dividing surface between a fixed mold and a movable mold.

Next, the configuration of the nonporous die casting apparatus of the present invention will be described with reference to FIGS. The mold is composed of a fixed mold 1 and a movable mold 2. A core (not shown) for forming a space in a casting as a product is inserted between the divided surfaces P of the molds 1 and 2, and a cavity is formed. 1a and 2a are formed. A sleeve 4 is connected to the cavities 1 a and 2 a via a runner 3, and a molten metal can be filled from a pouring port 4 a provided in the sleeve 4. Also,
A retractable piston 5 is fitted to the sleeve 4,
After pouring the molten metal from the pouring port 4a, the piston 5 is operated to push the molten metal into the cavities 1a and 2a.

On the other hand, a forced cooling path 6 for exerting a valve function is integrally formed on the upper portions of both the dies 1 and 2. The forced cooling passage 6 is interposed between the cavities 1a and 2a and the vacuum suction passage 7, and is usually kept open. When the molten metal fills the cavities 1a and 2a and rises, the molten metal is solidified. By closing the passage, it is possible to effectively prevent the molten metal from entering the vacuum suction passage 7, and is formed on the dividing surface P of the movable mold 2 by a groove such as a maze as shown in FIG. 2. By flowing the cooling water through the cooling water passage 8 in the vicinity, the molten metal inside the forced cooling passage 6 is cooled.

In the base 2b on the movable mold 2 side,
The cavities 1a and 2a are opposite to the movable mold half-split surface P.
An internal pressurizing device 9 is provided. The pressurizing device 9 is configured to inject a pressurized liquid into a cylinder 9a from a non-illustrated pressurized liquid injector to thereby insert a squeeze fitted into the base 2b and the insertion holes 2c and 2d of the movable mold 2 through a piston 9b. The squeeze pins 9c are pressed against the cavities 1a and 2c.
a Press the molten metal filled inside.

On the other hand, close to the runner 3 connected to the cavities 1a and 2a,
A cooling water passage 10 is provided. By flowing the cooling water through the cooling water passage 10, the molten metal in the runner 3 is rapidly solidified to close the passage, and the airtightness inside the cavities 1a and 2a can be obtained.

Next, a manufacturing process of an aluminum die cast according to this embodiment will be described with reference to FIGS. First, with the core interposed between the fixed mold 1 and
A load is applied to the movable mold 2 from the direction of the die base 11 to clamp the mold. Next, a molten metal such as an aluminum alloy is injected from the pouring port 4a, and the piston 5 is moved to set the pouring port to 4a.
After the blockage, the inside of the cavities 1a and 2a is evacuated by using a vacuum suction device (not shown) from the vacuum suction passage 7, and the piston 5 is driven to inject the molten metal. Thus, the injected molten metal passes through the runner 3 and is injected into the cavities 1a and 2a. At this time, the injection speed into the cavities 1a and 2a is set in the range of 2 to 15 m / s, so that the run-out failure which occurs when the above-mentioned filling speed is too low,
Oxidation due to atomization of the molten metal, which has occurred when the speed is too high, does not occur.

Before the end of the operation of the piston 5,
The molten metal filled in the cavities 1a and 2a further ascends and enters the forced cooling path 6, where it is rapidly cooled and solidified at a certain distance to block the inflow of the molten metal. At about the same time, cooling water is injected from the inlet 10a of the cooling water channel 10, the molten metal is rapidly solidified, the runner 3 is closed, and pressure leakage from inside the cavities 1a, 2a is prevented. Make the inside airtight. At this time, the injection of the molten metal by the pressurization of the piston 5 is stopped.
Immediately after this, the pressurized liquid is injected into the cylinder 9a of the pressurizing device 9, and the piston 9b is moved in the direction of the squeeze pin 9c.
The squeeze pins 9c press the molten metal filled in the cavities 1a and 2a.

When the molten metal solidifies and casting is completed,
The movable mold 2 is moved to open the mold, and the casting is removed from the movable mold 2. At this time, since the molten metal solidified in the forced cooling path 6 and the runner 3 is fixed to the product and solidified, it is separately processed to form the product into a desired shape.
Furthermore, since the injection speed of the molten metal is set in the range of 2 to 15 m / s described above to suppress oxidation due to atomization of the molten metal,
By performing the heat treatment, the tensile strength of the product, which was conventionally 220 MPa, is improved to 320 MPa.

In the above embodiment, the cooling water passage 10 is provided in the vicinity of the runner 3 at right angles to the direction of introduction of the molten metal. However, the cooling water passage 10 may be provided in the vicinity of the runner 3 in an arbitrary curved shape.

In the above embodiment, water is injected as a cooling medium into the cooling water passage 10. However, even if oil having a higher boiling point than water is used, the molten metal in the runner portion 3 can be effectively cooled. .

Further, in the above embodiment, the cooling water passage 10 is provided immediately before the cavities 1a and 2a of the runner 3, but the cooling water passage 10 may be provided at a distance from the cavities 1a and 2a.

[0024]

Since the apparatus of the present invention is configured as described above, by applying pressure before the molten metal in the cavity starts to solidify, uniform overall pressure can be applied to the molten metal. A product with a uniform specific gravity without pinholes or shrinkage cavities, especially in the case of aluminum die-cast, has a specific gravity of about 2.75.
g / cm @ 3 of product are obtained. Therefore, it is possible to manufacture a gear pump or a motor cover, which was impossible with the conventional die casting apparatus.

In the conventional local pressurization method, about 400 MPa
However, in the present invention, the solidification of the molten metal has not started at all as described above, and the molten metal is 200% lower than the local pressing method.
Even at a pressure of up to 300 MPa, uniform pressure can be applied to the entire molten metal. Therefore, the pressure device can be made compact, and the size of the entire device can be reduced. further,
The runner, which is the molten metal supply point, is cooled while applying the tensile force to the molten metal by the vacuum means, so that the air remaining in the cavity and the molten metal is discharged, and the supply of the molten metal is stopped when the molten metal is sufficiently filled. In addition, the tensile force of the vacuum means is transmitted to the molten metal in the cavity, and by applying uniform pressure to the molten metal in cooperation with the pressing means, the molten metal in the cavity before solidification can be formed. At this time, the precision of the tissue is promoted. At this time, since the runner portion is closed with the cooled molten metal, the tensile force by the vacuum means is efficiently transmitted to the molten metal, and the precision of the tissue is further promoted.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a nonporous die casting apparatus of the present invention.

FIG. 2 is a view taken in the direction of the arrow II in FIG.

Claims (1)

(57) [Claims] 1. A mold formed by a fixed mold and a movable mold, vacuum means for vacuuming the inside of the mold, and pressurizing means for pressurizing the inside of the mold. A non-porous die casting apparatus for solidifying the molten metal while being pressurized by an in-mold pressurizing means after filling the molten metal; a forced cooling path connecting the vacuum means and the inside of the mold; A non-porous die-casting device provided with a cooling means provided at a runner portion connected to the die and cooling the molten metal.