JP3128705B2 - Suction pressure casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suction pressure casting apparatus for casting.

[0002]

2. Description of the Related Art Conventionally, as this kind of suction pressure casting apparatus, there is one disclosed in Japanese Patent Application Laid-Open No. 62-114761, for example. In this casting apparatus, as shown in FIG. 3, the decompression chamber 1 is disposed on a low-pressure casting pressurizing chamber 2, and in the decompression chamber 1, a gate 4 from which a suction casting mold 3 hangs from the bottom is formed. It is disposed so as to be inserted into the crucible 5 in the pressurizing chamber 2.

[0003] The decompression chamber 1 is provided with suction control means 6. The suction control means 6 is connected to a suction pipe 10 reaching a vacuum pump 9 via an adjustment valve 7 and a receiver tank 8, and based on the pressure in the decompression chamber 1 detected via a pressure detector 11. ,
And a program controller 12 for controlling the regulating valve 7.

[0004] Further, the pressurizing chamber 2 for low-pressure casting includes a pressurizing chamber 2.
The pressurizing control means 15 detects the internal pressure via a pressure detector 18 and adjusts the pressing force of a pressurizing adjusting valve 17 of a pressurizing pipe 16 by a program controller 19.
It has.

In the device configured as described above,
When the pressure in the receiver tank 8 is reduced in advance by the vacuum pump 9 and the pressure in the pressure reducing chamber 1 is reduced by opening the regulating valve 7, the molten metal is simultaneously filled into the mold 3 through the gate. The decompression rate is determined by the program controller 12 while detecting the pressure in the decompression chamber 1 by the pressure detector 11.
Is controlled by.

Next, the program controller 19 is operated at a predetermined time during the depressurization to open the pressurizing adjusting valve 17 to start pressurizing the pressurizing chamber 2 and to provide a pressure necessary to prevent the occurrence of sink marks. To the molten metal. When the predetermined pressurizing time is completed, the chambers on the depressurized side and the pressurized side are opened to the atmosphere, and the casting is finished.

[0007]

However, in this conventional configuration, the program controller 19 is operated at a predetermined time during the depressurization of the decompression chamber 1 to open the pressurization adjusting valve 17 and to open the pressurization chamber 2. Since the pressure is applied, the timing of the hot water to the mold 3 is not reliable, and if the timing of the hot water is too early, casting burrs are generated.
If the timing is too late, there is a problem that nests are generated, and there is a problem that the cost is increased because the control is performed by the two control means 6 and 15.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to satisfactorily control the timing of hot water for a mold and to control the suction pressure by a single control means. It is intended to provide a device.

[0009]

According to the present invention, in order to solve the above technical problems, a mold is provided in a decompression chamber, and the pressure in the decompression chamber is reduced so that the molten metal in the furnace for holding the molten metal is moved through a stoke. In the suction-pressure casting apparatus, which pressurizes the molten metal holding furnace and applies pressure to the molten metal after casting in the casting mold, the evacuation flow rate of the vacuum pump is changed by a control means in the decompression circuit of the decompression chamber. A pressure reducing flow control valve capable of changing the flow rate of the pressurized air by the same control means is disposed in the pressurizing circuit of the molten metal holding furnace, and The differential pressure between the pressure in the depressurizing chamber and the pressure in the molten metal holding furnace is fed back to the control means, and the differential pressure-time pattern stored in the control means is compared and calculated,
Both the depressurizing flow control valve and the pressurizing flow control valve are provided so as to be controllable, and an electric signal that detects that the molten metal has been filled into the mold by a molten metal detection sensor disposed in the mold is inputted, The present invention resides in a suction pressure casting apparatus configured to operate a pressure circuit of a molten metal holding furnace and change a differential pressure-time pattern stored in the control means.

[0010]

According to the above construction, an electric signal which detects that the molten metal is filled in the mold is inputted by the molten metal detecting sensor provided in the mold, and the pressurizing circuit of the molten metal holding furnace is operated to operate the molten metal holding furnace. The timing of the hot water can be accurately performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a suction and pressure casting apparatus 21. The molten metal holding furnace 24 is provided at the lower part, and the decompression chamber 36 is provided at the upper part.

A molten metal holding furnace 24 having a predetermined volume is formed on a base 23 constituting a machine frame 22 of the casting apparatus 21, and a metal molten metal such as an aluminum alloy is provided substantially at the center of the molten metal holding furnace 24. A crucible 25 is placed so that 26 can be enclosed. An air supply port 27 and a pressure outlet 28 are formed in a corresponding furnace wall of the molten metal holding furnace 24, and the pressure outlet 28 is connected to a differential pressure sensor 29. Also,
The air supply port 27 is connected to a pressure source such as an external compressor through a pipe 30. The pipe 30 is provided with a pressure reducing valve 31, a pressurizing flow control valve 32, and valves 33 and 34 sequentially from the upstream side. ing.

Further, the upper part of the molten metal holding furnace 24 is
A lid is hermetically closed by a lower die base 35 provided to be able to move up and down along 2, and a decompression chamber 36 is formed above the lower die base 35.

The decompression chamber 36 is formed by combining a lower wall frame 37 and an upper wall frame 38, and the lower wall frame 37
Is attached to the lower die base 35 and the upper wall frame 38
Is mounted on the lower surface of a movable plate 40 which is moved up and down by an elevating cylinder 39 which is mounted downward on the upper part of the machine frame 22. A mold 41 composed of a lower mold 42 and an upper mold 43 is disposed in the decompression chamber 36, and a cavity 44 is formed on the mating surface of the upper and lower molds 42, 43. The lower die 42 is provided opposite to the lower die base 35 and is provided at a predetermined position of the lower die 42.
The stalk 46 has a length that penetrates the lower die base 35 and extends downward from the spout 45, and has a length that can be immersed in the metal melt 26 of the crucible 25 provided in the melt holding furnace 24. Is provided so that the molten metal 26 can be introduced into the cavity 44 through the stalk 46.

The lower wall frame 37 of the decompression chamber 36
The exhaust port 47 and the pressure output port 48
Is formed, the pressure outlet 48 is connected to the differential pressure sensor 29, the exhaust port 47 is connected to a vacuum pump 50 via a pipe 49, and the pressure reducing flow control valve 51 is sequentially connected to the pipe 49 from the upstream side. , A valve 52, a flow control valve 53, and valves 54 and 55, respectively.

The differential pressure sensor 29 and the flow control valves 32 and 51 thus arranged are connected to control means 56 constituted by a microcomputer. A molten metal detection sensor 57 is mounted in a substantially central portion of the upper mold 43 of the mold 41 so as to output an electric signal to the control means 56 when the cavity 44 is filled with the molten metal 26. Is provided.

In the control means 56, a time pattern SP-P1-P2-P3-P4-P5-P6 shown in FIG. 2 (differential pressure between chamber pressure and furnace pressure) is stored. Control is performed according to this differential pressure-time pattern.

In this apparatus 21, the control is performed according to the differential pressure-time pattern stored in the control means 56, that is, when the casting start button is pressed (S) in FIG. Is opened, the inside of the decompression chamber 36 is exhausted by the vacuum pump 50, the molten metal 26 is sucked, and the molten metal 26 is injected into the cavity 44 through the stalk 46. The injection start point is the point indicated by P1 in the figure. At the time indicated by P2 in the figure, the completion of filling into the cavity 44 is detected by the molten metal detection sensor 57, and this detection signal is input to the control means 56 as an electric signal. , The pre-stored differential pressure-time, S-P1-P2-P3-P4-P5-P6,
Differential pressure-time, S-P1-P2-P3'-P4'-P5 '
Automatically changed to -P6 '. Here, P2 and P3 'are the same time.

On the other hand, upon receiving the detection signal from the molten metal detection sensor 57, the valve 52 is closed, and the pressure in the pressure reducing chamber 36 is completed, and at the same time the valve 33 is opened, and the pressurization in the molten metal holding furnace 24 is started. That is, in FIG. 2, the inside of the holding furnace 24 is pressurized from the point P3 'to the point P4', and pressure is applied to the molten metal 26 in the cavity 44 to perform a hot-water feeding process. Thereafter, the period between P4 'and P5' is the time during which the feeder pressure is held, and this time is the feeder pressure holding time indicated by A. After the elapse of the hot water pressure holding time A, the valve 33 is closed and the valves 55 and 34 are opened from P5 'to P6', so that the inside of the decompression chamber 36 is supplied with air and the inside of the molten metal holding furnace 24 is exhausted. .
Natural cooling is performed within the evacuation time B, after which the movable plate 40 is moved up by the elevating cylinder 39, the upper die 43 is also moved up, and the product is taken out from the cavity 44, thereby completing one shot. Then, the lower die base 35 is moved upward to open the upper part of the molten metal holding furnace 24, and the crucible 2 is opened.
5, the lower die base 35 and the movable plate 40 are moved down again to return to the state of FIG. 1 and casting is performed.

When the control according to the differential pressure-time pattern shown in FIG. 2 is performed by the control means 56, a signal from the differential pressure sensor 29 is input to the control means 56, and based on this signal, The comparison operation is performed in the control means 56, and the result is sent to the flow control valves 51 and 32 as an electric signal, and the valve openings of the flow control valves 51 and 32 are adjusted and controlled. The control can be performed by the control by 56, and the cost can be reduced.
At a substantially central portion of the upper mold 43 of the mold 41, a molten metal detection sensor 57 is buried and provided so as to output an electric signal to the control means 56 when the molten metal 26 is filled in the cavity 44. Melt holding furnace 24 based on signal
Is pressurized, so that the timing of hot water to the cavity 44 can be accurately performed, and the product quality can be improved.

[0021]

According to the above-mentioned structure,
When the control in accordance with the differential pressure-time pattern is performed by the control means, a signal from the differential pressure sensor is input to the control means. Based on this signal, a comparison operation is performed in the control means. An electric signal is sent to the flow control valve and the flow control valve for pressurization, and the valve opening of both flow control valves is adjusted and controlled. Therefore, the control can be performed by one control means, and the cost is reduced. In particular, a molten metal detection sensor is buried almost at the center of the upper mold of the mold, and provided so as to output an electric signal to the control means when the cavity is filled with the molten metal. Since the molten metal holding furnace is configured to be pressurized based on the signal, the timing of pushing the molten metal into the cavity can be accurately performed, and the product quality can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a suction pressure casting apparatus.

FIG. 2 is a diagram showing a differential pressure-time pattern input to a control means.

FIG. 3 is a schematic view of a conventional suction pressure casting apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 21 Suction pressure casting apparatus 24 Melt holding furnace 25 Crucible 26 Melt 29 Differential pressure sensor 30 Piping (pressurizing circuit) 32 Flow rate control valve for pressurizing 36 Depressurizing chamber 41 Mold 43 Upper mold 44 Cavity 46 Stoke 49 Piping (Depressurizing circuit) 50 Vacuum pump 51 Depressurization flow control valve 56 Control means 57 Molten metal detection sensor

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-228605 (JP, A) JP-A-5-169231 (JP, A) JP-A-62-248551 (JP, A) JP-A-5-228551 96356 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 18/04 B22D 18/06 B22D 18/08

Claims (1)

(57) [Claims] 1. A mold is provided in a decompression chamber, and the pressure in the decompression chamber is reduced to fill the molten metal in the molten metal holding furnace into the mold through stalk. In a suction and pressure casting apparatus for casting by applying pressure to the molten metal, a pressure reducing flow control valve capable of changing an exhaust flow rate of a vacuum pump by a control unit is provided in a pressure reducing circuit in the pressure reducing chamber, A pressurizing flow control valve capable of changing the flow rate of pressurized air by the same control means is also provided in a pressurizing circuit in the molten metal holding furnace. The differential pressure is fed back to the control means, the differential pressure stored in the control means is compared with a time pattern, and a comparison operation is performed, and both the pressure reducing flow control valve and the pressurizing flow control valve are provided so as to be controllable. An electric signal that detects that the molten metal has filled the mold is input by a molten metal detection sensor disposed on the mold, the pressurizing circuit of the molten metal holding furnace is operated, and stored in the control means. A suction and pressure casting device configured to be able to change the differential pressure-time pattern.