JPH08290232A - Insert in die casting equipment - Google Patents

Abstract

PURPOSE: To form a casting free from surface fold defect. CONSTITUTION: Many fine grooves 8... are serrated in the axial direction on the outer peripheral surface of an insert 7 mounted in the direction roughly orthogonal to flow of molten metal, recessed grooves 10 communicating with these grooves 8 are formed on end fane, further, an exhaust hole 9 connecting to outside is arranged in the center, the gas entrapped at pouring is released to outside from these grooves 8 and exhaust hole 9, the entrapment of gas, which is a cause of surface fold, is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nest used for a die casting apparatus.

[0002]

2. Description of the Related Art For example, when casting a knuckle arm for an automobile, a cavity corresponding to the shape of the knuckle arm is formed in a vertical direction, and the molten metal is introduced from the lower end of the cavity for gravity casting. A die is used, and in order to form such a knuckle arm, a complicated cavity corresponding to the shape and a nest for forming a smooth large-diameter shaft hole that forms a through hole of the shaft are required. become.

Therefore, when the molten metal is poured into the mold of this type, the molten metal flowing into the cavity from the lower end is divided into left and right portions at the nest portion and largely disturbed, and gas is entrained and solidified as it is. There is a problem that wrinkles are generated on the peripheral surface of the.

In order to solve such a problem, the apparatus proposed by the present applicant in Japanese Patent Laid-Open No. 269541/1993 has a large number of fine grooves formed on the surface of a nest in the axial direction, and these grooves are used. Adding resistance to the flow of molten metal
Although the speed is made gentle and uniform, the intake of residual gas is suppressed as much as possible. There is room for further improvement in that it cannot completely prevent the inclusion of

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to:
Another object of the present invention is to provide a new nest capable of effectively discharging the entrained gas and further suppressing the generation of wrinkles due to this gas.

[0006]

That is, according to the present invention, as a nest in a die casting apparatus for achieving such a subject, a center portion of a nest mounted in a direction substantially perpendicular to the flow of the molten metal, The outer peripheral surface is provided with a large number of fine grooves parallel to the axial center, and the end face of this nest has at least a large number of recesses communicating with the grooves on the outer peripheral surface. The groove is formed so that the generation of wrinkles due to the intake of gas is suppressed as much as possible.

[0007]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows a nest which is an embodiment of the present invention, and FIGS. 2 and 3 show an example of a knuckle arm forming die using the nest. .

First, a mold device for molding a knuckle arm will be described with reference to FIGS.
In the fixed mold and the movable mold for gravity casting shown in,
A lateral runner 5 extending laterally is provided at the lower end of a vertical runner 4 communicating with the sprue 3, and cavities 6, 6 corresponding to the shape of the knuckle arm are vertically connected thereto. The molten metal injected from the sprue 3 flows into the cavities 6, 6 from the lower end thereof.

By the way, FIG. 1 shows a shaft hole forming insert which is provided on the side of the movable mold 2 and which constitutes an embodiment of the present invention. The outer peripheral surface of the axle hole forming portion of the insert 7 has a semicircular cross section. Are formed in parallel with each other in the axial direction with an appropriate gap. These grooves 8 ... Add resistance to the flow of the molten metal and enable the flow around the nest 7. The insert 7 is configured to be as gentle and uniform as possible, and an exhaust hole 9 communicating with a hole 11 provided in the movable mold 2 is provided at the center of the insert 7, and the end face of the insert 7 is further provided at the end face thereof. ,
A large number of concave grooves 10 ... Which communicate with the respective grooves 8 on the outer peripheral surface and the exhaust holes 9 are cut, and the gas taken into the cavity 6 is discharged to the outside of the molds 1 and 2. Is configured.

In the figure, reference numeral 12 indicates a nest provided on the fixed mold 1 side to form the other end of the shaft hole, and 13 indicates a core pin nest. A shallow recess 14 is formed in the root part of the mold, that is, in the parting surface of the fixed mold.
4, an overhang is formed on the product to prevent cracks caused by burrs.

The sprue 3 is attached to the molds 1 and 2 thus constructed.
When the molten metal is injected from the inside of the cavity 6, the molten metal rapidly rises and hits the shaft hole forming portion of the insert 7 and is split into left and right. At that time, the gas is largely disturbed and gas is entrained. From the groove 8 provided around the hole forming portion, the gas directly flows to the outside, and the remaining gas is discharged from the concave groove 10 provided at the end face of the insert 7 to the central discharge hole 9 and the peripheral groove 8.
To the outside of the molds 1 and 2 and to be retained in the cavity 6 as much as possible, and the generation of hot wrinkles is prevented.

As described above, the concave groove 10 provided on the end surface of the insert 7 has a function of guiding the entrained gas to the groove 8 on the peripheral surface or the discharge hole 9 at the center. Therefore, these concave grooves 10 are provided. 1 may be formed radially from below to above so as to guide the gas from below into the groove 8 and the discharge hole 9 as shown in FIG. 1 (a), or
As shown in (b), the exhaust holes 9 may be radially formed from the exhaust holes 9 toward the grooves 8 ...

Although the present invention has been described with reference to the example of the insert for forming the axial hole, any other cross-sectional shape may be adopted as long as the insert is arranged in the direction orthogonal to the flow of the molten metal. The present invention can also be applied to nesting.

[0014]

As described above, according to the present invention, a large number of fine grooves are provided in the direction parallel to the axis on the outer peripheral surface of the insert, which is attached in a direction substantially perpendicular to the flow of molten metal. On the end face of the insert, a concave groove communicating with these grooves was provided, and a discharge hole was provided in the center, so the gas entrained when the molten metal hit the insert,
Some of them escape directly to the groove on the outer peripheral surface, and the rest escape to the center discharge hole or the groove on the outer peripheral surface through the concave groove on the end surface to prevent gas from being caught in the product. ,
It is possible to form a good product that does not cause wrinkles.

Moreover, the ridges formed on the inner surface and the end surface of the hole of the molded product by these fine grooves can be easily removed by the finishing process after the mold release, and these grooves are formed at the time of casting. Even if a hot water wrinkle is created by the gas taken in by catching, these hot water wrinkles
It can be easily scraped off by finishing at the time of mold release.

[Brief description of drawings]

1 (a) and 1 (b) are enlarged perspective views of a nest which constitutes an embodiment of the present invention.

FIG. 2 is a plan view showing an example of a mold using this insert.

FIG. 3 is a side view showing the same mold in section.

[Explanation of symbols]

 1, 2 Mold 6 Cavity 7 Nesting 8 Circumferential groove 9 Exhaust hole 10 End face recess

Claims (1)

[Claims] 1. An exhaust hole communicating with the outside is provided at the center of a nest mounted in a direction substantially perpendicular to the flow of molten metal, and a large number of fine holes parallel to the axis are provided on the outer peripheral surface. A nest in a die casting apparatus, characterized in that a groove is provided and a plurality of recessed grooves communicating with the groove are formed on an end surface of the nest.