JPH1094868A - Pressurized casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a large quantity of high precision products by a die casting method. SOLUTION: A metallic parts 5 as a part of the cast product is housed in a housing part 6 arranged at the position facing a cavity 4 in a die device so as to project this part into the cavity 4. Thereafter, molten metal is press- poured into this cavity 4 by a pressurized pouring device 9 and further, when the molten metal becomes half-melted, the molten metal in the cavity 4 is integrally cast with the metallic parts 5 at high pressure by advance-driving a third die 3 to secondarily pressurized the molten metal in the cavity 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method for integrally casting a metal part which is to be a part of a product in a cavity.

[0002]

2. Description of the Related Art In a conventional die casting method, a molten metal is injected into a cavity of a mold by using a pressure injection means at a high pressure, so that it can be poured in a short time and a thin product can be formed. it can. Further, since the mold is easily separated as a split mold and can be cast by repeatedly using the same mold, it is suitable for mass production. In addition, since the casting is performed by pouring at a high pressure, a product having a relatively thin and relatively complicated shape can be molded with high precision.

[0003]

However, in the above-described conventional die casting method, a product having a thin and relatively complicated shape can be formed, but the product to be cast has a complicated shape. In such a case, there are problems in that the number of divided molds is increased in order to make it possible to remove the mold, and thus the accuracy of the mold is reduced, and that the assembling, clamping, and removing the mold require time and effort. In addition, if a part of the product to be cast has a narrow portion such as a thin plate or a small-diameter rod that serves as a passage for the molten metal, it is difficult to fill the molten metal into the plate-shaped or rod-shaped portion. There was a problem that meat and nests were easily formed.

[0004] Therefore, the usual die casting method is as follows.
It is not suitable for casting such as those having a complicated shape and high precision, those having a complicated shape and difficult to remove, and those in which a molten metal passage cannot be formed widely.

[0005] The present invention has been made in view of the above circumstances, and even if it is unsuitable for a normal die casting method such as a complicated shape or a wide molten metal passage cannot be formed, die casting can be performed without causing a casting defect. It is an object of the present invention to provide a pressure casting method that can be used.

[0006]

Means for Solving the Problems and Actions As a means for solving the above-mentioned problems, the pressure casting method according to the present invention employs a method in which a concave portion is provided at a position facing a cavity of a die casting die. A metal part to be a part of a product to be cast by a die casting mold is housed so that a part of the metal part protrudes into the cavity, and then the molten metal is injected under pressure into the cavity, and the injected molten metal is vented. Then, when the molten metal is cooled to be in a semi-molten state, the volume of the cavity is reduced so that the molten metal is secondarily pressurized and cast integrally with the metal component.

In the pressure casting method, the pressure is adjusted so that the pressure of the molten metal in the cavity does not become excessive during the secondary pressing.

Therefore, as described above, the storage portion formed at the position facing the cavity of the die casting mold,
A metal part to be a part of a product to be cast is housed, and a part of the metal part is protruded into the cavity. In this state, a molten metal is injected into the cavity under pressure. Then, when the injected molten metal is in a semi-molten state, when the molten metal in the semi-molten state is secondarily pressurized by reducing the volume of the cavity,
The molten metal pressurized to a high pressure is securely and closely integrated with the metal parts projecting into the cavity without any gap, and is integrally and precisely cast.

In the above pressure casting method, if the pressure in the cavity is adjusted so that the pressure in the cavity does not become excessive during the secondary pressurization, it is possible to prevent the precision of the product from being lowered due to the deformation of the die, and to shorten the life of the die. Extend.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pressure casting method according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a die casting die apparatus for performing a pressure casting method according to a first embodiment of the present invention. In this die apparatus, a metal part 5 constituting a part of a product to be cast is shown. Are separately molded, and are integrally molded during die casting, thereby facilitating die cutting and simplifying mold division.

Therefore, this mold apparatus is composed of the first mold 1
, A second mold 2 and a third mold 3, and a cavity 4 is formed substantially at the center of the three molds 1, 2, 3. In the first mold 1, a storage portion 6 for storing a metal component 5 in a plate shape or a block shape, which is a part of a product cast by the mold device, is recessed at a position facing the cavity 4. Has been established. The third mold 3 is slidably fitted into the second mold 2 and a cavity 4 formed between the fitted third mold 3 and the first mold 1. A gate 8 is provided which communicates with a first mold 1 via a runner 7 formed between the first mold 1 and the first mold 1.

A piston 9a of a pressure injection device 9 driven by hydraulic pressure is slidably fitted in the gate 8, and the molten metal is pressed into the cavity 4 from the gate 8 by the piston 9a. It can be injected under pressure. Further, when the third mold 3 slidably fitted to the second mold 2 is advanced by a hydraulic cylinder, a toggle mechanism or a crank mechanism (not shown), the third mold 3 approaches the first mold 1. 1 (in the left direction in FIG. 1), the volume of the cavity 4 is reduced.
The molten metal inside is further pressurized.

Next, the operation of this embodiment performed by using the die casting die apparatus configured as described above will be described.

First, the third mold 3 is retracted to open the cavity 4, and a plate-shaped or block-shaped metal part 5 is housed and fixed in the housing 6 formed facing the cavity 4. At this time, since the metal part 5 is formed larger than the storage part 6, one end side (the right end side in FIG. 1) of the metal part 5 projects into the cavity 4.

Next, the third mold 3 is advanced and the second mold 2 is moved.
After fitting into the cavity 4 of the first, second, third
The molten metal is poured into the cavity 4 surrounded by the molds 1, 2, and 3. Pouring is performed from a gate 8 and is pressurized and injected at a predetermined pressure by a pressure injection device 9 to fill the entire cavity 4 in a short time.

At the time of pouring, the air in the cavity 4 is smoothly discharged, and the air entrained by the molten metal is discharged out of the mold, thereby preventing the occurrence of gas defects such as bubble cavities.

The molten metal in the sprue 8 is naturally cooled while being pressurized at a predetermined pressure by the piston 9a of the pressure injection device 9, and when the molten metal in the cavity 4 is in a semi-molten state, the third mold is formed. 3 is advanced and the molten metal in the semi-molten state is secondarily pressurized.

At the time of the secondary pressurization, the pressurizing force by the pressurizing / injecting device 9 is reset to a desired pressure so that the secondary pressurizing force by the second mold 2 becomes excessive. In addition, it is possible to prevent a reduction in molding accuracy due to mold deformation, a reduction in mold life, a mold breakage, and the like, which are caused when the secondary pressurizing force is too large by operating as a relief valve.

Therefore, according to the pressure casting method of this embodiment, when the molten metal injected under pressure is in a semi-molten state, the third mold 3 is driven forward to perform secondary pressurization, whereby the cavity 4 is pressed. In order to cast the molten metal inside at a higher pressure, for example, in a case where a plurality of plate-shaped metal parts 5 are arranged side by side at a narrow interval and one side thereof is united and integrally cast, the cavity 4 is used. The molten metal is filled without gaps between the plates of the portion protruding into the inside. As a result, it is possible to reliably prevent the occurrence of casting defects such as underfills and cavities, and to cast each plate-shaped metal component in a state where it is firmly integrated on one side thereof.

FIG. 2 shows a die casting die apparatus for performing a pressure casting method according to a second embodiment of the present invention. In the first embodiment, the inside of the cavity 4 in a semi-molten state is shown. As a method of secondary pressurizing the molten metal, the third mold 3 slidably disposed is driven forward to reduce the volume of the cavity 4 and pressurize. A piston 17 is provided in the cylinder 14, and the piston 17 is driven to press the molten metal in the cavity 14. This embodiment will be described below with reference to the drawings.

This mold apparatus comprises a first mold 11, a second mold 12, and a third mold 13, and the three molds 1 are provided.
A cavity 14 is formed substantially at the center of 1, 12, and 13. In the first mold 11, a storage portion 16 for storing a metal component 15 in a plate shape or a block shape, which is a part of a product cast by the mold device, is recessed at a position facing the cavity 14. Has been established. The third mold 13 is slidably fitted to the second mold 12, and a cavity 14 is formed between the fitted third mold 13 and the first mold 11. I have. Also, the second mold 12
Is provided with a sprue (not shown), and a pressurizing and pouring device for pressurizing and injecting the molten metal from the sprue into the cavity 14 via the sprue.

The piston 17 is disposed on the side of the third mold 13 facing the cavity 14 so as to be slidably in contact with the inner surface of the cavity 14 so as to be vertically movable in FIG. It is connected to the lower end of a piston rod 17a that penetrates substantially the center of the mold 13 in the vertical direction, and is driven forward by a hydraulic cylinder (not shown).

Next, the operation of this embodiment performed by using the die-casting die apparatus configured as described above will be described. Before assembling the third die 13 to the die apparatus, first,
After the metal part 15 is housed and fixed in the housing part 16 so that a part of the metal part 15 projects into the cavity 14, the third mold 1
3 and the cavity 14 is sealed.

When the molten metal is pressurized and injected into the cavity 14 sealed by the pressure injection device, the air in the cavity 14 is discharged outside the mold, and the air caught in the molten metal is also separated and discharged. Then, when the molten metal is naturally cooled to be in a semi-molten state, the piston 17 is driven forward to secondarily pressurize the molten metal in the cavity 4.

Therefore, according to the pressure casting method of this embodiment, when the molten metal that has been injected under pressure is in a semi-molten state, the piston 17 is driven forward to perform secondary pressurization. Can be further pressurized, so that the molten metal is cast at a high pressure as in the case of the first embodiment.
Even if the portion protruding inward has, for example, a complicated shape, a product integrated with the metal component 15 can be cast without generating casting defects such as nests.

In each of the above embodiments, the plate-shaped or block-shaped metal parts 5, 1 constituting a part of the product are used.
5 is integrally cast as a product, but other examples include a rod-shaped metal part, a net-like metal part such as a metal lath and an expanded metal, a perforated plate or a corrugated plate such as a punching metal, or the like. The present invention can also be suitably performed when a plurality of sheets are integrally cast.

[0028]

As described above, according to the heat casting method of the present invention, a metal part constituting a part of a product to be cast is separately formed, and the metal part is integrally cast when die casting is performed. Therefore, the die can be easily removed, and the mold division can be simplified. In addition, when the molten metal in the cavity is in a semi-molten state, it is subjected to secondary pressurization and casting at a higher pressure, so that what could not be cast without precision casting can be molded with high precision by die casting, Further cost reduction can be achieved. Further, since the casting cycle time can be shortened, it is suitable for mass production and the production cost can be reduced.

Further, when the pressure is adjusted by the pressure injection means so that the pressure in the cavity does not become excessive at the time of the secondary pressurization, it is possible to prevent the deformation of the mold, the reduction of the molding accuracy, the shortening of the life of the mold and the like due to the excessive pressure. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing a die casting die apparatus used in a first embodiment of a pressure casting method of the present invention.

FIG. 2 is a sectional front view showing a die-casting die apparatus used in the second embodiment.

[Explanation of symbols]

4,14 ... cavity, 5,15 ... metal parts, 6,
16: storage section, 7: runner, 8: gate, 9: pressurized injection device, 17: piston.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Saito 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Yoshihiro Nagaki 1-1-1, Kiba, Koto-ku, Tokyo Stock Company Inside Fujikura

Claims (2)

[Claims] 1. A metal part which is to be a part of a product to be cast by a die casting die is protruded into the cavity in a storage portion recessed at a position facing the cavity of the die casting die. Then, the molten metal is injected into the cavity by pressurizing, and the injected molten metal is evacuated and cooled. When the molten metal is cooled to a semi-molten state, the volume of the cavity is reduced to reduce the volume of the molten metal. A pressure casting method characterized by performing a subsequent pressurization and casting integrally with the metal component. 2. The pressure casting method according to claim 1, wherein during the secondary pressurization, the pressure is adjusted so that the pressure of the molten metal in the cavity does not become excessive.