JPS6043226B2 - casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting apparatus, and particularly to a molten metal (hereinafter referred to as hot water) in a bottom pouring type casting apparatus.

) into the mold. As a general casting device, there is a bottom pouring type casting device as shown in FIG.

This is a reservoir 2 that stores hot water 1, and a reservoir 2 that stores hot water 1.
A tank 4 forming a pressurized chamber 3 above the liquid level, and a lower end opening 5
A mold 6 immersed in hot water, a mold chamber 8 that houses the mold 6, is isolated from the pressurizing chamber 3 by a seal ring 7, and is pressure-related to the inside of the mold 6, and A differential pressure gauge 9 that measures the difference in pressure in the mold chamber 8, a pressure supply path 10 that supplies pressure to the pressurizing chamber 3, and a pressure supply path 10 that is interposed in the pressure supply path 10, and The control valve 10 is equipped with a control valve 10 that can adjust the opening degree of the flow path, and the supply pressure is adjusted by operating the control valve 11 in accordance with the pressure difference instruction from the differential pressure measurement gauge 9. By applying pressure to the liquid surface of the hot water 1, the hot water 1 passes through the lower end opening 5 into the mold 6.
It is designed to be pushed up, rolled, and cast.
This kind of casting equipment enables stable casting, prevents turbulence during casting, and draws out the hot water from below the surface of the hot water, preventing slag floating on the surface from getting mixed into the product. It has the advantage of being preventable and improving quality.

FIG. 2 shows a bottom pouring type casting apparatus using a mold 6A manufactured by the roast wax method or the like, and is substantially the same as that shown in FIG. 1.

By the way, in such casting equipment, the pressure applied to the surface of the molten metal creates the pushing up condition of the molten metal, that is, the casting condition, so it is important to determine the casting speed, which affects the quality of the cast product. 'Become. Pushing up the hot water quietly and without interruption has the most important effect on the quality of the cast product. Therefore, operating the control valve 11 requires an extremely high degree of skill. Therefore, there have been provided casting apparatuses that automatically control operations that require a high level of skill, and a conventional casting apparatus of this type is shown in FIG. 3.

In FIG. 3, a differential pressure detector 12 is attached to detect the differential pressure between the mold chamber 8 and the pressurizing chamber 3, and a comparator 14 is connected to this detector 12 via an amplifier 13. ing. A reference differential pressure setting device 15 is connected to the comparator 14 on the other hand, and the set value inputted from this setting device 15 and the actual differential pressure value inputted from the differential pressure detector 12 are compared and calculated. Accordingly, a predetermined control signal is outputted accordingly. The output end of the comparator 14 is connected to a servo motor 17 via an amplifier 16, and the servo motor 17 receives the control signal and adjusts the pressure or flow rate regulating valve 18 provided in the pressure supply path 10 as appropriate. It is designed to be driven. This control valve 18 is driven and adjusted by a servo motor 17 to adjust the flow path opening degree of the pressure supply path 10 and adjust the pressure supply from the pressure supply means 19 to a predetermined value. However, the conventional automatically controlled casting apparatus configured as described above has the following drawbacks.

First, the casting time is short, ranging from a few seconds to more than ten seconds, although it varies depending on the size of the mold. When the pressure suddenly decreases, it is necessary to increase the pressure or the amount of gas, but the control system using the servo motor as described above cannot keep up with this. Second, depending on the shape of the mold, it may be necessary to incorporate a program that changes the casting speed from the initial stage to the middle stage to the final stage even during a short casting period, but the control system described above is sufficient. It is difficult to expect a similar follow-up.

In addition, FIG. 4 is a diagram showing an example of a differential pressure fluctuation due to leakage in a sealed portion between a mold chamber and a pressurizing chamber, and FIG. 5 is a diagram showing an example of a differential pressure program.

An object of the present invention is to eliminate the drawbacks of the prior art and provide a casting device with excellent followability. In order to obtain excellent followability, the present invention provides a plurality of pressure supply paths in parallel,
A channel on-off valve is provided in each supply channel, the operating part of which is connected to a comparator, and the number of openings and closings of the on-off valve is adjusted as appropriate depending on the degree of differential pressure. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 shows an embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 3 have the same constituent functions as the aforementioned constituent elements. In FIG. 6, the pressure supply path 10 has a plurality of electromagnetic on-off valves that open and close their own flow paths, and are interposed in parallel with each other. The pressure or amount of gas supplied is
It is designed to increase or decrease depending on the number of openings and closings.

Each of the electromagnetic operating parts 22 in each valve 21 has a comparator 1
4 through amplifiers 16, and are mutually connected by the control signal output from the comparator 14. They operate in conjunction with each other and drive each valve 21 to open and close, respectively.
As shown in FIG. 7, as the output of the amplifier increases, the number of valves 21 to be opened and closed is reduced. Next, the effect will be explained. For example, when there is a sudden drop in differential pressure due to a leak between the pressurizing chamber 3 and the mold chamber 8, as shown in FIG. Since the command signal value is rapidly reduced, the number of electromagnetic operating units 22 that operate according to this value increases.

Therefore, since the number of valves 22 to be opened and closed increases, the pressure or amount of gas supplied from the pressure supply path 10 to the pressurizing chamber 3 increases rapidly, and the drop in differential pressure due to the leak is immediately compensated for. , proper pushing up of the hot water 2, that is, casting is ensured.In this case, the on-off valve 2 by the electromagnetic operation part 22
Since the opening/closing operation time of each of the valves 1 can be set to 1/2 or less, the response speed is dramatically improved compared to the conventional control operation time for the control valve 18 using a servo motor as described above. . In addition, in the above embodiment, the compensation operation to cope with a drop in differential pressure due to an unexpected accident was explained, but if you want to obtain a predetermined pressure supply according to a casting program assumed in advance according to the shape of the mold,
For example, a differential pressure program as shown in FIG. 5 may be output from the comparator. Even in such a case, each on-off valve 2
1 has extremely good responsiveness, so even when increasing or decreasing the pressure supply for an extremely steep rise, as shown in Figure 5,
A supply sufficiently corresponding to this will be realized. As described above, according to the present invention, a plurality of pressure supply paths are provided in parallel with each other, and the number of openings and closings of each on-off valve provided in each supply path is adjusted based on the output signal from the comparator. This improves responsiveness and allows it to comply with all requests.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional manual casting device, Fig. 2 is a block diagram showing a modified example, Fig. 3 is a block diagram showing a conventional automatic control casting device, and Fig. 4 is a block diagram showing pressure leakage. FIG. 5 is a diagram showing an example of differential pressure fluctuation, FIG. 5 is a diagram showing an example of a differential pressure program, FIG. 6 and FIG. 7 are diagrams showing an example of the present invention, and FIG. , FIG. 7 is a diagram showing the relationship between the output of the amplifier and the number of valves to be opened and closed. 1... Hot water, 3... Pressurized chamber, 5...
... lower end opening, 6 ... mold, 8 ... mold chamber, 10 ... pressure supply path, 12 ... ...
Differential pressure detector, 13, 16... Amplifier, 14...
...Comparator, 15...Reference differential pressure setting device, 1
9...Pressure supply means, 21...Opening/closing valve, 22...
・・・・・・Electromagnetic operation part.

Claims (1)

[Claims] 1. A molten metal reservoir for storing molten metal, a pressurizing chamber formed above the liquid surface of the molten metal, a mold chamber that is independent from the pressurizing chamber and housing a mold whose lower end opening is immersed in the molten metal, and a pressurizing chamber. A pressure supply path that supplies pressure to the chamber, a differential pressure detector that detects the difference between the pressure in the pressurized chamber and the pressure in the mold chamber, and the differential pressure detected by the differential pressure detector as a set value. A casting apparatus equipped with a comparator for comparison, which has a plurality of pressure supply paths in parallel, each pressure supply path has a flow path on-off valve, and an operating part of each flow path on-off valve is connected to the comparator. A casting apparatus characterized in that the number of openings and closings of the flow path opening/closing valve is adjusted based on a signal output from a comparator.