JPH038547A - Metallic mold for suction casting - Google Patents

Abstract

PURPOSE:To suck air flowing from parting face to outer part and to prevent involution of the air by arranging a flowing air suction passage sucking the air flowing from gap between the parting faces to outer part in outside of product cavity and runner in the facing face of a metallic mold for suction casting. CONSTITUTION:In the metallic mold A for suction casting providing the product cavity 12 arranged to the parting face 10, the runner 16 arranged to the parting face 10 and communicating with a sprue 14 and the product cavity 12 and cavity air suction passage 18 communicating with the product cavity 12 and for sucking the air in the product cavity 12 to outer part, by sucking the air in the product cavity 12 through the cavity air suction passage 18, the air in the outer part flows toward the product cavity 12 and the running 16 from the gap between the parting faces 10, but as the flowing air suction passage 20 is arranged at outer part of the product cavity 12 and runner 16 in the parting face 10, the air flowing from the outer part is sucked to the outer part through the flowing air suction passage 20 before reaching to the product cavity 12 and the runner 16.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in a suction casting mold.

(Prior art) In order to make the mold last longer, it is desirable to inject molten metal as low as possible into a casting mold. However, when low-temperature molten metal is injected, the flowability of the molten metal deteriorates. There is a problem. In particular, in casting molds that produce many thin-walled products, such as those used to cast small parts for automobiles, in order to reduce the weight of cast parts and improve productivity, Since the volume of the product cavity is small and the runner must be long, the temperature of the flowing molten metal tends to drop, and the iA rounding properties of the molten metal are significantly deteriorated.

Therefore, in order to deal with this report, we have recently begun
A suction casting mold to which a suction casting method is applied is proposed in Japanese Patent No. 31463.

This mold for suction casting includes a product cavity provided on a mating surface, a runner provided on the mating surface that communicates a sprue with the product cavity, and a runner that communicates with the product cavity to allow a flow from inside the product cavity. It is equipped with a cavity air suction passage that sucks air to the outside, and the air inside the product cavity is sucked to the outside through this cavity air suction passage. It aims to improve sexuality.

(Problem to be Solved by the Invention) However, in the above-mentioned suction casting mold, when the air inside the product cavity is suctioned through the cavity air suction passage, external air is generated between the mating surfaces of the mold. It flows into the product cavity or runner through the gap. For this reason, there is a problem in that the incoming air gets caught up in the molten metal in the suction casting mold, causing blowholes in the resulting cast product.

In view of the above, the present invention prevents external air from flowing into the product cavity or runner through the gap between the mating surfaces, even though the air inside the product cavity is sucked, and thereby, The purpose is to prevent blowholes from forming in cast products.

(Means for Solving the Problems) In order to achieve the above object, the present invention sucks air flowing in from the gap between mating surfaces to the outside before this flowing air reaches the product cavity or runner. It is.

Specifically, the similar solution of the present invention includes a product cavity provided on a mating surface, a runner provided on the mating surface that communicates a sprue with the product cavity, and a runner that communicates with the product cavity and communicates with the product cavity. Assuming a suction casting mold is equipped with a cavity air suction passage for sucking air inside the product cavity to the outside, air flows into the product cavity and the outside of the runner at the mating surfaces from the gap between the mating surfaces. The structure is such that an inflow air suction passage is provided for suctioning the air to the outside.

(Function) With the above configuration, when the air inside the product cavity is sucked through the cavity air suction passage, external air flows toward the product cavity and runner from the gap between the mating surfaces, but Since the inflow air suction passage is provided outside the runner, air flowing in from the outside is sucked to the outside through the inflow air suction passage before reaching the product cavity and the runner.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a cross-sectional structure of a suction casting mold A according to an embodiment of the present invention, and FIG. 2 shows the overall structure of a suction casting apparatus to which the suction casting mold A is applied.

The suction casting mold A according to this embodiment is for molding a large number of bearings, for example eight, which are cast products.
On the mating surface 10 of this suction casting mold A, eight product cavities 12 are arranged in two stages, upper and lower. A pressure sensor 13 that detects the pressure within the product cavity 12 is disposed inside.

The lower end 12a of each product cavity 12 is provided on the mating surface 10 and communicates with the sprue 14, while communicating with the downstream end of a runner 16 that branches in the middle.
The upper end portions 12b are provided on the mating surface 10 and communicate with the upstream ends of the cavity air suction passages 18 that merge in the middle.

Further, the cavity air suction passage 18 opens to the outside of the suction casting mold A at a cavity air suction port 18a that is the downstream end thereof.

An inflow air suction passage 20 is provided in a substantially circumferential shape on the outer peripheral edge of the mating surface 10 of the suction casting mold A, that is, on the outside of the product cavity 12 and the runner 16. is open to the outside of the suction casting mold A at both ends of the inflow air suction passage 20a.

Cavity air suction port 18a and inflow air suction port 20a
A plate-shaped suction palate 22 having a through hole 22a is provided above the
Thereby, the cavity air suction port 18a and the inflow air suction passage 20a communicate with the outside of the casting mold A through the through hole 22a. Furthermore, four portions 22a are formed on the air suction ports 18a and 2Oa side of the suction port lid 22, and in this recessed portion 22a, a sintered filter 24 having air permeability obtained by sintering alloy powder is integrated with the suction port lid 22. With this sintered filter 24,
Air passes through the through hole 22a, but the molten metal is prevented from passing through.

A pouring container 26 for storing molten metal to be supplied to the product cavity 12 is disposed above the sprue 14 of the suction casting mold A. It communicates with the sprue 14 via the pouring spout 26a, which allows external air to flow from the sprue 14 into the product cavity 12.
This prevents it from flowing into the interior. Also, pouring container 2
A refractory material 26b is attached to the inner surface of the refractory material 2.
A temperature sensor 28 for detecting the temperature of the molten metal in the pouring container 26 is disposed on the inner surface of the molten metal 6b.

A frame 32 that supports a hydraulic cylinder 30 is disposed above the pouring container 26, and this frame 32
The base 32a is placed on the upper surface of the pouring container 26 and also serves as a heat-insulating lid for the pouring container 26.

Inside the pouring container 26 is a rod-shaped spout plug 3 made of graphite.
4 are arranged in the vertical direction, and the upper part of the sprue plug 34 passes through the inside of a cylindrical guide bush 36 fitted to the base 32a of the frame 30. Further, the upper end of the sprue plug 34 is supported by the lower end of the piston rod 30a of the hydraulic cylinder 30, and can be moved up and down as the hydraulic cylinder 30 is driven. This spout plug 34 is lowered, and the large-diameter frame 34a provided at the lower end of the spout plug 34 is opened to the pouring spout 2 of the pouring container 26.
6a and the sprue 14 of the suction casting mold A,
The supply of the molten metal in the pouring container 26 to the sprue 14 is stopped, and conversely, the sprue plug 34 is raised and the frame 34a is closed to the pouring spout 26.
a and the sprue 14, the molten metal in the pouring container 26 is supplied into the product cavity 12.

In FIG. 2, 38 is a vacuum pump that produces reduced pressure air, 40 is a buffer tank that communicates with the vacuum pump 38 and stores the reduced pressure air produced by the vacuum pump 38, and 42 communicates between the buffer tank 40 and the suction port 22. When the vacuum pump 38 is driven, air in the product cavity 12 and the inflow air suction passage 20 is sucked through the cavity air suction port 18a and the inflow air suction port 20a.

Further, in FIG. 1, 48 is a control unit with a built-in CPU, and this control unit 48 controls the pressure of the product cavity 12 detected by the pressure sensor 13.
When the pressure within the product cavity 12 becomes lower than the set value and the inside of the product cavity 12 is in a state where elution can be sucked, and the temperature of the molten metal within the pouring container 26 detected by the temperature sensor 28 falls below the set value, the melt is poured. When the molten metal reaches a temperature that will not damage the inside of the suction casting mold A, the hydraulic cylinder 30 is driven to raise the sprue plug 34 to supply the molten metal in the pouring container 26 to the sprue 14.

When casting is performed using the suction casting mold A having such a structure, the molten metal in the pouring container 26 is sucked by the negative pressure in the product cavity 12 and is filled into the product cavity 12 through the runner 16. be done. At this time, since the inside of the product cavity 12 and the runner 16 are in a reduced pressure state, external air flows into the product cavity 1 from the gap created between the mating surfaces 10.
2 and the runner 16, but this inflow air meets the inflow air suction passage 20 before reaching the product cavity 12 or the runner 16, and is sucked to the outside through this inflow air suction passage 20. . In this way, according to the suction casting mold A according to this embodiment, the inflowing air does not reach the product cavity 12, so that external air is not drawn in during elution.

(Effects of the Invention) As explained above, according to the suction casting mold according to the present invention, since the inflow air suction passage is provided outside the product cavity and runner on the mating surfaces, air flows in from the gap in the mating surfaces. is sucked to the outside through the inflow air suction passage before reaching the product cavity and runner, which prevents outside air from being drawn into the molten metal in the product cavity or runner. It is possible to reliably prevent blowholes from occurring in cast products.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a suction casting mold according to an embodiment of the present invention, and FIG. 2 is a sectional view of a suction casting apparatus to which the suction casting mold is applied. A... Suction casting mold 10... Matching surface 12... Product cavity 14... Sprue 16... Runway 18... Cavity air suction passage 20... Inflow air suction passage

Claims (1)

[Claims] (1) A product cavity provided on the mating surface; a runner provided on the mating surface that communicates the sprue with the product cavity; and a runner that communicates with the product cavity and sucks air in the product cavity to the outside. In a suction casting mold equipped with a cavity air suction passage for suction, an inflow air suction is provided outside the product cavity and runner on the mating surfaces to suck air flowing in from the gap between the mating surfaces to the outside. A suction casting mold characterized by being provided with a passage.