JP2019136716A - Low pressure casting machine - Google Patents

Abstract

To provide a low pressure casting machine capable of keeping the pressure in a pressurization chamber into a prescribed pressure value.SOLUTION: A low pressure casting machine 1 where an inert gas is introduced into a pressurization chamber 11 and a molten metal M is pressurized, comprises: the pressurization chamber 11; an exhaust passage communicated with the pressurization chamber 11; and a first check valve 25 and a second check valve 26 provided at the exhaust passage. The first check valve 25 allows the flow-out of the gas from the pressurization chamber 11 in the case the pressure in the pressurization chamber 11 is a first pressure value or higher, the first pressure value being higher than the outside pressure of the first check valve 25, and the second check valve 26 allows the flow-in of the gas to the pressurization chamber 11 in the case the pressure in the pressurization chamber 11 is a second pressure value or lower, the second pressure value being lower than the outside pressure of the second check valve 26.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a low pressure casting machine.

  As a method for producing a high-quality casting product with few defects, a low-pressure casting method is known in which a gas is fed into a pressurizing chamber and a molten metal in the pressurizing chamber is filled into a mold. In the low pressure casting method, an inert gas such as argon may be used as a gas for pressurization in order to prevent the molten metal from being oxidized. Patent Document 1 discloses the structure of a low-pressure casting machine that performs low-pressure casting using an inert gas.

International Publication No. 2008/132991

  In the low-pressure casting machine according to Patent Literature 1, the pressurizing chamber is always a closed space except during supply and exhaust so that no gas other than the inert gas flows into the pressurizing chamber. However, if the temperature in the pressurizing chamber rises with the pressurizing chamber closed, the gas expands and the pressure in the pressurizing chamber rises, and there is a possibility that the molten metal overflows in the mold. On the other hand, when the temperature in the pressurizing chamber decreases, the gas contracts, the pressure in the pressurizing chamber decreases, and the molten metal may flow to the air supply port or the exhaust port.

  This invention is made | formed in view of such a situation, Comprising: The low-pressure casting machine which can maintain the pressure in a pressurization chamber within a predetermined pressure value is provided.

  A low pressure casting machine according to the present invention is a low pressure casting machine that introduces an inert gas into a pressurizing chamber to pressurize a molten metal, the pressurizing chamber, an exhaust passage communicated with the pressurizing chamber, A first check valve and a second check valve provided in the exhaust passage, wherein the first check valve is configured such that the pressure in the pressurizing chamber is an external pressure of the first check valve. Allowing the gas to flow out of the pressurizing chamber when the pressure value is higher than the first pressure value, and the second check valve is configured so that the pressure in the pressurizing chamber is outside the second check valve. In the case where the pressure is equal to or lower than the second pressure value lower than the atmospheric pressure, the inflow of gas into the pressurizing chamber is permitted.

  In the low pressure casting machine according to the present invention, the first check valve and the second check valve are provided in the exhaust passage. The first check valve permits gas to flow out of the pressurizing chamber when the pressure in the pressurizing chamber is equal to or higher than the first pressure value higher than the external atmospheric pressure. For this reason, it can suppress that the pressure in a pressurization chamber rises too much and a molten metal overflows to the metal mold | die side. The second check valve permits gas to flow into the pressurizing chamber when the pressure in the pressurizing chamber is equal to or lower than a second pressure value lower than the external atmospheric pressure. For this reason, it can suppress that the pressure in a pressurization chamber falls too much and a molten metal flows into an air supply port or an exhaust port.

  According to the present invention, it is possible to provide a low-pressure casting machine capable of maintaining the pressure in the pressurizing chamber within a predetermined pressure value.

It is sectional drawing which shows the outline of the low pressure casting machine which concerns on 1st Embodiment. It is sectional drawing which shows the outline of the low pressure casting machine which concerns on 2nd Embodiment when the gas in a pressurized chamber expand | swells. It is sectional drawing which shows the outline of the low pressure casting machine which concerns on 2nd Embodiment when the gas in a pressurized chamber shrink | contracts.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

[First Embodiment]
First, the overall configuration of the low-pressure casting machine 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing an outline of the low-pressure casting machine 1. As shown in FIG. 1, the low-pressure casting machine 1 includes a main body 10, a mold 15, pipes 21 to 23, a solenoid valve 24, a first check valve 25, and a second check valve 26. And comprising. The main body 10 is a device for filling the mold 15 with the molten metal M, and includes a pressurizing chamber 11, a holding chamber 12, an on-off valve 13, and a runner 14. The molten metal M is, for example, a molten metal such as aluminum.

  The pressurizing chamber 11 communicates with the holding chamber 12 through a communication hole, and the communication hole can be closed by the on-off valve 13. The holding chamber 12 is a space for holding the molten metal M. By opening the on-off valve 13, the molten metal M in the holding chamber 12 can be filled into the pressurizing chamber 11.

  The runner 14 is a flow path for the molten metal M and communicates with the pressurizing chamber 11 and the mold 15. The mold 15 is a pair of molds, for example, and has an internal structure corresponding to a cast product. The molten metal M is cooled and solidified in the mold 15 to produce a cast product.

  The pipes 21 to 23 are pipes through which an inert gas such as argon passes. The pipe 21 is connected to an inert gas supply source (not shown) such as a cylinder and an electromagnetic valve 24. The pipe 22 is connected to the pressurizing chamber 11 and the electromagnetic valve 24. The pipe 23 has, for example, a bifurcated shape, and is connected to the first check valve 25, the second check valve 26, and the electromagnetic valve 24.

  The electromagnetic valve 24 is a drive valve having a three-way connection port. Among them, the connection port connected to the pipe 22 is always open. The connection port connected to the pipe 21 opens when the solenoid valve 24 is turned on and closes when the power is turned off. The connection port connected to the pipe 23 is closed when the electromagnetic valve 24 is turned on and opened when the power is turned off. That is, when the power is turned on, the solenoid valve 24 connects the pipe 21 and the pipe 22 and shuts off the pipe 22 and the pipe 23. On the other hand, when the power is turned off, the solenoid valve 24 connects the pipe 22 and the pipe 23 and blocks between the pipe 21 and the pipe 22.

  The first check valve 25 and the second check valve 26 are check valves that allow gas to flow in only one direction. The first check valve 25 opens when the pressure in the pipe 23 is equal to or higher than a first pressure value that is higher than the external pressure of the first check valve 25. For example, the first check valve 25 can be opened when the pressure in the pipe 23 is 1 kPa or more higher than the external pressure of the first check valve 25. At this time, the gas in the pipe 23 flows out to the outside.

  When the pipe 22 and the pipe 23 are connected, since the pressurizing chamber 11 and the pipe 23 are in communication, the pressure in the pressurizing chamber 11 is equal to the pressure in the pipe 23. Therefore, in this case, the first check valve 25 is connected to the first check valve 25 from the pressurization chamber 11 when the pressure in the pressurization chamber 11 is equal to or higher than the first pressure value higher than the external pressure of the first check valve 25. Allow gas outflow.

  The second check valve 26 opens when the pressure in the pipe 23 is equal to or lower than a second pressure value lower than the external pressure of the second check valve 26. For example, the second check valve 26 can be opened when the pressure in the pipe 23 is 1 kPa or more lower than the external pressure of the second check valve 26. At this time, external gas flows into the pipe 23.

  When the pipe 22 and the pipe 23 are connected, since the pressurizing chamber 11 and the pipe 23 are in communication, the pressure in the pressurizing chamber 11 is equal to the pressure in the pipe 23. Therefore, in this case, the second check valve 26 is supplied to the pressurization chamber 11 when the pressure in the pressurization chamber 11 is equal to or lower than the second pressure value lower than the external pressure of the second check valve 26. Allow inflow of gas.

  In the present specification, “the external pressure of the check valve” refers to the atmospheric pressure outside the check valve. That is, the first pressure value is higher than the pressure outside the first check valve 25, and the second pressure value is lower than the pressure outside the second check valve 26. For example, when the first check valve 25 and the second check valve 26 are respectively provided in the atmosphere, the external pressure of the first check valve 25 and the external pressure of the second check valve 26 Are both atmospheric pressures. Further, when the outside of the check valve is a closed space, the pressure in the closed space is the external pressure of the check valve.

Here, the flow in the case of performing low pressure casting using the low pressure casting machine 1 will be described.
The open / close valve 13 is closed before casting. Further, the power supply of the solenoid valve 24 is turned off, and the piping 21 and the piping 22 are disconnected.
First, the molten metal M is supplied to the holding chamber 12 from a hot water supply port (not shown). Thereafter, the on-off valve 13 is opened, and the molten metal M is filled in the pressurizing chamber 11. After the molten metal M is filled in the pressurizing chamber 11 by a predetermined amount, the on-off valve 13 is closed.

  After the molten metal M is filled in the pressurizing chamber 11 and the on-off valve 13 is closed, the electromagnetic valve 24 is turned on. That is, the piping 21 and the piping 22 are connected, and the piping 22 and the piping 23 are disconnected. At this time, an inert gas is introduced into the pressurizing chamber 11 from an inert gas supply source (not shown) through the pipe 21, the electromagnetic valve 24, and the pipe 22. That is, the pipe 21, the electromagnetic valve 24, and the pipe 22 function as an air supply path for introducing an inert gas into the pressurizing chamber 11 in this case. The inert gas flows along the direction of the arrow shown in the vicinity of the pipe 21 in FIG.

  When an inert gas is introduced into the pressurizing chamber 11, the molten metal M in the pressurizing chamber 11 is pressurized. The pressure in the pressurizing chamber 11 at the time of pressurization is higher than the first pressure value. For example, the pressure in the pressurizing chamber 11 can be a pressure value that is higher by about 10 to 50 kPa than the external air pressure of the first check valve 25. The pressurized molten metal M is filled into the mold 15 through the runner 14. The molten metal M filled in the mold 15 is cooled and becomes a cast product.

  When the molten metal M filled in the mold 15 is cooled, the electromagnetic valve 24 is turned off to stop the supply of the inert gas to the pressurizing chamber 11. That is, the piping 22 and the piping 23 are connected, and the piping 21 and the piping 22 are disconnected. At this time, since the pressure in the pressurizing chamber 11 is equal to or higher than the first pressure value, the first check valve 25 is opened, and the inert gas in the pressurizing chamber 11 is exhausted to the outside. That is, the pipe 22, the electromagnetic valve 24, and the pipe 23 function as an exhaust path that discharges the inert gas from the pressurizing chamber 11. The inert gas flows along the direction of the arrow shown in the vicinity of the pipe 23 in FIG.

  When the inert gas in the pressurizing chamber 11 is exhausted and the pressure becomes lower than the first pressure value, the first check valve 25 is closed. At this time, the space in the pressurizing chamber 11 and the exhaust path is closed in a state filled with an inert gas. For this reason, the oxidation reaction etc. of the molten metal M can be suppressed and the quality of the molten metal M can be maintained.

  Here, the case where the temperature in the pressurizing chamber 11 rises in a state where the pressurizing chamber 11 and the space in the exhaust passage are closed will be described. When the temperature in the pressurizing chamber 11 increases, the inert gas expands and the pressure in the pressurizing chamber 11 increases. When the pressure in the pressurizing chamber 11 becomes equal to or higher than the first pressure value, the first check valve 25 is opened and the inert gas is exhausted. In such a configuration, the pressure in the pressurizing chamber 11 does not exceed the first pressure value. Therefore, it is possible to suppress the pressure in the pressurizing chamber 11 from rising and the molten metal M from overflowing to the mold 15 side.

  Next, the case where the temperature in the pressurization chamber 11 falls in the state where the pressurization chamber 11 and the space in the exhaust passage are closed will be described. When the temperature in the pressurizing chamber 11 decreases, the inert gas contracts and the pressure in the pressurizing chamber 11 decreases. When the pressure in the pressurizing chamber 11 becomes equal to or lower than the second pressure value, the second check valve 26 is opened and external gas is supplied. In such a configuration, the pressure in the pressurizing chamber 11 does not fall below the second pressure value. Therefore, it is possible to suppress the pressure in the pressurizing chamber 11 from decreasing and the molten metal M from flowing into the pipe 22.

  As described above, the low-pressure casting machine 1 according to this embodiment can maintain the pressure in the pressurizing chamber 11 between the first pressure value and the second pressure value. For this reason, it can suppress that the molten metal M flows out into the metal mold | die 15 or the piping 22. FIG.

[Second Embodiment]
Next, the low-pressure casting machine 2 according to the second embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view showing an outline of the low-pressure casting machine 2 according to the present embodiment when the gas in the pressurizing chamber 11 expands. FIG. 3 is a cross-sectional view schematically showing the low-pressure casting machine 2 according to the present embodiment when the gas in the pressurizing chamber 11 contracts.
As shown in FIGS. 2 and 3, the low-pressure casting machine 2 includes a bag body 27 and a housing 28 in addition to the configuration of the low-pressure casting machine 1 in the first embodiment.

The bag body 27 is a bag-shaped member that communicates with the exhaust path and accommodates an inert gas. The bag body 27 is deformable, and the amount of inert gas contained in the bag body 27 is variable. In the present embodiment, the bag body 27 is connected to the pipe 22, but the bag body 27 may be connected to the pipe 23. The bag body 27 may be formed of a flexible material such as a synthetic resin such as polyethylene or polypropylene, or may be a container having a stretchable structure such as a bellows structure.
The housing 28 is installed so as to cover the bag body 27. The housing 28 is preferably formed of a material having a strength higher than that of the bag body 27.

Here, the case where the gas in the pressurizing chamber 11 expands in a state where the pressurizing chamber 11 and the space in the exhaust passage are closed will be described with reference to FIG. When the gas in the pressurizing chamber 11 expands, as shown in FIG. 2, the bag body 27 receives the gas from the pressurizing chamber 11 while expanding. For this reason, the pressure rise in the pressurizing chamber 11 can be suppressed.
Moreover, since the housing | casing 28 is provided so that the bag body 27 may be covered, even if the bag body 27 bursts, it can suppress that the fragment | piece of the bag body 27 and the gas inside are scattered. Further, by making the housing 28 smaller than the expansion volume of the bag body 27, it is possible to prevent rupture due to expansion.

  Next, a case where the gas in the pressurizing chamber 11 contracts in a state where the pressurizing chamber 11 and the space in the exhaust passage are closed will be described with reference to FIG. When the gas in the pressurizing chamber 11 contracts, as shown in FIG. 3, the bag body 27 sends the gas into the pressurizing chamber 11 while contracting. For this reason, the pressure drop in the pressurizing chamber 11 can be suppressed.

As described above, in the low pressure casting machine 2 according to this embodiment, the pressure fluctuation in the pressurizing chamber 11 can be further suppressed.
In addition, when using the raw material whose heat-resistant temperature is not high for the bag body 27, it is preferable to install the bag body 27 in the position away from the pressurization chamber 11 1 m or more. In this case, since the gas in the pressurizing chamber 11 is sufficiently cooled to the outside air and then accommodated in the bag body 27, the influence of heat on the bag body 27 can be suppressed.

Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention.
For example, in the above-described embodiment, the configuration in which a part of the piping is common to the air supply path and the exhaust path has been described, but each may be configured by another pipe.

  In the above embodiment, the case where the outside of the second check valve 26 is the atmosphere has been described. However, even if the second check valve 26 is stored in a casing filled with an inert gas. Good. In this case, since the gas flowing into the pressurizing chamber 11 from the second check valve 26 is an inert gas, it is possible to suppress a gas other than the inert gas from flowing into the pressurizing chamber 11. . In addition, when taking such a structure, the external atmospheric pressure of the second check valve 26 becomes the pressure in the housing that houses the second check valve 26.

DESCRIPTION OF SYMBOLS 1, 2 Low pressure casting machine 10 Main-body part 11 Pressurizing chamber 12 Holding chamber 13 On-off valve 14 Runway 15 Mold 21-23 Pipe 24 Electromagnetic valve 25 First check valve 26 Second check valve 27 Bag 28 Case M Molten metal

Claims (2)

A low-pressure casting machine that introduces an inert gas into a pressurizing chamber and pressurizes the molten metal,
The pressure chamber;
An exhaust passage communicating with the pressurizing chamber;
A first check valve and a second check valve provided in the exhaust passage,
The first check valve allows gas to flow out of the pressurizing chamber when the pressure in the pressurizing chamber is equal to or higher than a first pressure value higher than the external pressure of the first check valve. ,
The second check valve allows gas to flow into the pressurizing chamber when the pressure in the pressurizing chamber is equal to or lower than a second pressure value lower than the external pressure of the second check valve. ,
Low pressure casting machine. Further comprising a bag body that communicates with the exhaust path, accommodates the inert gas, and has a variable capacity.
The low-pressure casting machine according to claim 1.

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