JPS59202148A - Evacuating device for die - Google Patents

Abstract

PURPOSE:To rise a valve head part which closes an evacuating passage by a static pressure to prevent the outflow of a molten metal by providing bypass passages communicating with an evacuating port to the evacuating passage for the molten metal in a cavity in such a way as to generate pressure head on the valve head part. CONSTITUTION:After the inside of a cavity 10 is forcibly evacuated, a molten metal is charged thereon. If the inertial force of the molten metal is small, the molten metal filled in the cavity is filled in bypass passages 14, 16 without lifting a valve head part 28 even if the molten metal contacts the part 28. The pressure head H is thus generated on the valve head part 28 of a stopper 24. The static pressure by the head H rises the stopper 24 by overcoming the own weight of the stopper 24 and the elastic force of a spring 25 then the part 28 closes an evacuating port 30 to shut off an evacuating passage 12 and the assages 14, 16 from the outside thereby preventing the outflow of the molten metal to the outside of the die.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to the mold exhaust gmt of a die-casting machine, and in particular, a method for preventing outflow of molten metal from an exhaust passage that can be adjusted according to the inflow speed of molten metal. Mold exhaust system r1tVc
It is related to

[Prior art]

In the mold device of a die-casting machine, in order to obtain a cast product without cavities, an on-off valve is provided in a part of the movable mold or fixed mold that forms the cavity, and in a part of this exhaust passage as well as the cavity. Prior to injecting the molten metal into the cavity, the gas in the cavity is sufficiently exhausted from the exhaust passage, and then the on-off valve is fully automatically closed by the inertia of the molten metal injected into the cavity, so that the bath water does not flow out to the outside. A mold exhaust system configured as described above has been proposed and put into practice.

As this type of mold exhaust device, one having the configuration shown in FIG. 1, for example, is known. That is, in FIG. 1, reference numeral 10 indicates a cavity 4 formed in a dividing surface of a fixed mold or a movable mold, and an exhaust passage 12 communicating with the cavity 0 is provided in a part of the mold. There is.

This exhaust passage 12 is provided with a pair of left and right bypass passages 14 and 16 along the mating surface of the mold, and these passages 1
4.16 communicates with an exhaust port 18 that communicates with the outside.

However, the exhaust passage]2 exhaust port 18&C4j cylinder 20 is provided, and the cylinder 20 has an r valve 22? −
Arrange. This valve 22 is located at the rear end (upper part in figure c)
An r stopper 24 is provided and a spring 26' is provided at the rear end of the r stopper 24.
f-engaged and resiliently held such that the valve head 28 closes the exhaust passage 12 and places the bypass passage 14.16 in communication with the exhaust port 18 prior to injection of molten metal.

As a result, the conventional mold exhaust configured in this way *ih,
Before pouring bath water into the cavity 1 ( ), the gas of 10 yen communicates with the cavity through the exhaust port 30 provided on one side of the cylinder 20 via the bypass passage 14. be forcibly evacuated by means.

On the other hand, in the rfA where the molten metal is injected into the cavity 10, when the bath water fills the cavity 1(), it enters the exhaust passage 12 and goes straight inside this passage 12'(), so the molten metal has a large size. After waiting for the inertia force, the valve head 28vc of the valve 22 comes into contact.

As a result, the valve 22 moves upward in the figure against the elasticity of the spring 26, and the valve head 28 comes into contact with the opening of the cylinder 20, closing the 18 exhaust ports. Therefore, in this state,
Since the exhaust passage J2 and the bypass passages 14, 16 are shut off from the outside, the molten metal is prevented from flowing out of the mold. The cylinder 20 housing the valve 22 is appropriately provided with an operating cylinder 32 that can move the cylinder to separate the solidified molten metal from the valve when the mold is opened.

However, in the conventional mold exhaust device described above, the valve provided for the exhaust passage is moved by the inertia of the molten metal to close the exhaust port. If the injection speed is slow, sufficient inertial force cannot be generated in the bath water. For this reason, the closing operation of the valve delays the advancing speed of the molten metal, and a portion of the molten metal flows out from the exhaust port during this time.

Therefore, the inventor of the present invention conducted various studies in order to overcome all the problems of the conventional mold exhaust device mentioned above, and found that the exhaust passage provided in the cavity was maintained at a sufficiently high position near the valve head of the stopper. By increasing the head of water from the valve head of the stopper, even if the inertial force of the molten metal cannot be generated and the closing action of the valve is slower than the advancing speed of the molten metal, the static pressure will continue to close the valve head of the stopper. It has been determined that the molten metal can be prevented from flowing out by raising the molten metal.

[Purpose of the invention]

In a mold exhaust system that has an on-off valve installed in a part of the exhaust passage that communicates with the mold cavity, even if the inertia of the molten metal is small and the stopper does not rise, the stopper can be fully raised by static pressure. An object of the present invention is to provide a mold exhaust device that completely prevents the leakage of bath water.

[Rest of invention]

In the present invention, in a mold exhaust device including an on-off valve in a part of an exhaust passage having a bypass passage communicating with a mold cavity, the exhaust passage is completely closed off in the bypass passage communicating with the exhaust port of the valve. Located higher than the valve head,
It is characterized by the stopper being raised by static pressure to maintain the pressure head.

[Embodiments of the invention]

Next, embodiments of the mold exhaust system according to the present invention will be described in group a below with reference to all the attached drawings. FIG. 2 is a sectional view of a main part showing an embodiment of the present invention, and in the figure, parts 5-5 that have the same functions as those in FIG. In FIG. 2, the bypass passages 14 and 16 are elevated so as to have a higher water head H than the valve head 28, as shown in FIG.

The operation of the mold exhaust system of the present invention having such a configuration will be explained.

Before injection of molten metal into the cavity 10, the bypass passage 1 is opened from the exhaust port 30 provided on one side of the cylinder 20.
4.16? The gas in the cavity 10, which is communicated through the cavity 10, is forcibly exhausted by an externally provided exhaust means If. When the molten metal □ is injected into the cavity 10, when the cavity 10 is filled with bath water having a small inertial force, it enters the exhaust passage 12Vc and comes into contact with the valve head 28. In this state, the weight of the stopper 24 and the elasticity of the spring 26 are greater than the inertia of the molten metal, so the stopper 24 does not rise and remains in the state shown in the figure. - 10,000, exhaust passage 12 is bypass passage 14.1
6vc is in communication, the molten metal that has come into contact with the stopper 24 gradually begins to fill the bypass passage 14.16, and as shown in the figure, the valve head 28Vr of the stopper 24
For example, when a pressure head of HJ is generated, the static pressure of this pressure head rHJ overcomes the weight of the stopper 24 and the elasticity of the spring 26, causing the stopper 24 to rise and the valve head 28 to close the 18 exhaust ports. With this F, the exhaust passage 12 and the bypass passages 14, 16 are shut off from the outside, and molten metal is prevented from flowing out of the mold.

〔Effect of the invention〕

As is clear from the foregoing, according to the present invention, the valve can be moved in several ways depending on the relationship between the inertia of the molten metal and the pressure to keep the valve closed. Since the water head created by the continuous bypass passage can maintain the static pressure inside the mold cavity, even if the injection speed of bath water is slow, the valve can be closed securely and the molten metal can flow out of the mold. Prevention is completely possible.

Furthermore, by devising the shape of the exhaust blood path within the mold cavity in the present invention, the operation of the exhaust valve can be ensured.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part showing the basic structure of a conventional mold exhaust system, and FIG. 2 is a cross-sectional explanatory view of a main part showing an embodiment of a mold exhaust system according to the present invention. 10... Cavity, 12... Exhaust passage, 14.1
6... Bypass passage, 18... Exhaust port, 20...
Cylinder, 22... Valve, 24... Stopper, 26...
・Spring, 28... Valve head, 30... Exhaust port, 32.
...Operation cylinder. Applicant: Toshiba Machine Co., Ltd. No. 1M No. 2 (¥I

Claims (1)

[Claims] In a mold exhaust system, an exhaust passage with a bypass passage communicating with a mold cavity is provided, and a part of this exhaust passage is provided with an on-off valve. Open the exhaust port of the closed valve [
A mold exhaust device characterized in that the communicating bypass passage is held at a high position.