JPH08294763A - Vacuum die casting apparatus - Google Patents

Abstract

PURPOSE: To provide a vacuum die casting apparatus, in which the vacuum degree in a cavity is accurately measured and a defective casting is not cast. CONSTITUTION: In the vacuum die casting apparatus in which the cavity 9 is formed of a fixed die 1 and a movable die 5 and a gas venting passages 19, 20, 20A are provided for connecting the cavity 9 to the outside of the die, a sensor hole 22 is arranged near the cavity 9 of the gas venting passage 20A. A pressure sensor 23 for measuring the vacuum degree is arranged at the side wall of the sensor hole 22 and molten metal shut-off mechanisms 24, 25 for opening/closing the opening part 22a of the sensor hole 22 are arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum die casting apparatus used in a die casting method, and more particularly to means for accurately detecting the degree of vacuum in a cavity.

[0002]

2. Description of the Related Art Conventionally, as a means for detecting the degree of vacuum of a cavity in a vacuum die casting apparatus, Japanese Patent Laid-Open No. 56-
The technology disclosed in Japanese Patent No. 144855 is disclosed. This technique will be described with reference to the schematic configuration diagram of FIG. In FIG. 4, the reference numeral 101 indicates a fixed mold, the reference numeral 102 indicates a movable mold, and a cavity 103 is formed between them. The cavity 103 communicates with the injection sleeve 104 via the runner 104a, and the injection sleeve 1
At 04, a molten metal pouring port 105 is formed. Reference numeral 106 denotes an injection cylinder, an injection plunger 107 is connected to the tip of the piston rod, and a plunger tip 108 is fixed to the tip of the injection plunger 107. The plunger tip 108 is inserted into the injection sleeve 104. Slidably fitted.

The rod of the injection cylinder 106 is provided with a striker 109. At a position where the tip of the striker 109 can contact, a low vacuum primary decompression start limit switch LS-1 and a high vacuum secondary decompression start. Limit switch LS-2 and high-speed injection limit switch LS-3 are arranged. On the other hand, the fixed mold 10
1 and the movable die 102 are partially formed with a gas vent groove 110. The tip of the gas vent groove 110 is branched into bypasses 110a and 110a and fixed to the fixed die 101 side. And the valve 11 of the automatic air vent valve 111 provided on the mating surface with the movable mold 102.
The tip ends of the bypasses 110a and 110a are open on both sides of 2. In FIG. 4, the bypass 110a is drawn in the molds 101 and 102 for clarity, but in reality, the bypass 110a is processed into a groove shape on the separation surface of the movable mold 102. 111a is a compression spring, and 111b is a cylinder.

That is, the automatic air vent valve 111
4, as shown in FIG. 4, on the separation surface portion of the molds 101 and 102, the gas vent groove 110 guided from the cavity 103,
The valve 112 that slides in the axial direction of the gas vent groove 110 at the end of the gas vent groove 110 by the direct action of the melt to be injected coming from the cavity 103, and the gas vent groove 11
Bypass 11 diverted from the middle of 0 to the side of valve 112
No. 0a is provided, and the passage is provided in the valve portion so that the passage and the cutoff between the bypass 110a and the outside can be directly controlled by the movement of the valve 112 in the axial direction.
The auto air vent valve 111 utilizes a difference in specific gravity between gas and molten metal, for example, a difference in specific gravity between air and molten aluminum being about 1: 2000, and a difference in inertial force based on this difference in specific gravity. Is. Valve 112
Does not close by the action of the gas having a low specific gravity that first advances, and is automatically closed by directly contacting the lower surface of the valve 112 with the molten metal having a high specific gravity that follows the gas. As a result, the cavity 103
The gas inside is sufficiently discharged, but the molten metal is not discharged outside beyond the valve 112 and the bypass 110a.

A pipe 113 is led out from the middle of the automatic air vent valve 111, and the tip of the pipe 113 is further branched into first and second pipes 114 and 115. It is connected to a vacuum tank 118 for low vacuum via a check valve 116 and an electromagnetic switching valve 117. The vacuum tank 118 is connected to a low vacuum vacuum pump 119 driven by a motor M. The electromagnetic switching valve 117 is switched by a signal from the limit switch LS-1 for starting the primary pressure reduction. On the other hand, the second pipe 115 is connected to a high-vacuum vacuum tank 122 via a check valve 120 and an electromagnetic switching valve 121, and the vacuum tank 122 is a high-vacuum vacuum pump 123 driven by a motor M. It is connected. Reference numeral 124 indicates a pressure gauge.

[0006]

However, in the above-mentioned prior art, a pressure gauge for measuring the degree of vacuum is provided between the mold and the vacuum device in order to check the degassing state in the cavity. , The gas vent passage connecting the cavity and the outside of the mold is clogged with the release agent, aluminum dust, etc.,
Even if the degree of vacuum in the cavity is not sufficient, if there is a vacuum between the mold and the vacuum device, it is judged that the cavity is sufficiently degassed, and a cast product with a lot of cavities is cast. There is a problem that it does.

The present invention has been made in view of the above conventional problems, and an object of the invention according to claim 1, 2, 3 or 4 is to accurately measure the degree of vacuum in the cavity and to perform defective casting. An object of the present invention is to provide a vacuum die casting apparatus that does not cast a product.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1, 2, 3 or 4 forms a cavity with a fixed mold and a movable mold, and separates the cavity and the outside of the mold. In a vacuum die casting apparatus having a connecting gas vent passage, a sensor hole is provided in the vicinity of the cavity of the gas vent passage, a pressure sensor for measuring a degree of vacuum is provided on a side wall of the sensor hole, and an opening of the sensor hole is provided. It is characterized in that a melt shutoff mechanism for opening and closing the section is provided.

[0009]

In the operation of the invention according to claim 1, 2, 3 or 4, a sensor hole is provided near the cavity of the gas vent passage,
Since the pressure sensor for measuring the degree of vacuum is arranged on the side surface of the sensor hole, the degree of vacuum of the cavity is accurately measured and a signal is transmitted to the control device. In the operation of the invention according to claim 2,
In addition to the above functions, a molten metal detection means is provided in the vicinity of the cavity of the runner that supplies the molten metal to the cavity. The vacuum degree of the cavity is measured until just before the cavity is filled with the molten metal. In the operation of the invention according to claim 3, in addition to the above operation, a plunger position detecting means for detecting the plunger position of the casting machine is provided, and the plunger position detecting means detects the plunger position and sends a signal to the control device. Since the molten metal interruption mechanism is driven by the signal from the control device, it functions as a substitute for the molten metal detecting means provided near the cavity of the runner. In the operation of the invention according to claim 4, in addition to the above-mentioned operation, by providing an air purge mechanism having an air discharge port between the opening of the sensor hole and the pressure sensor, the mold release at the opening of the sensor hole is achieved. Discharge the agent and aluminum dust to ensure that the molten metal blocking mechanism operates.

[0010]

[Embodiment 1] FIG. 1 shows Embodiment 1 and is a schematic configuration diagram of a vacuum die casting apparatus. In FIG. 1, 1 is a fixed type,
It is fixed to the fixed die plate 2, and the fixed die 1 has a hot water supply port 3
The injection sleeve 4 having is fixed. A movable die 5 is fixed to a movable die plate 8 via a spacer block 6 and a mounting plate 7. The fixed mold 1 and the movable mold 5 are opened by a casting machine (not shown) at the position of PL. A cavity 9 is formed by the fixed die 1 and the movable die 5. Denoted at 10 is an extruding pin, which is adapted to be fitted in the movable die 5 so as to be slidable. The left end of the push pin 10 is fixed to the push plate 11. Reference numeral 12 is a return pin, and like the push pin 10, its left end is the push plate 1
It is fixed to No. 1 and is configured so that it can be fitted into the movable mold 5 and can slide. The right end of the return pin 12 is in contact with the PL surface of the fixed die 1 and has a function of pushing the push plate 11 back by clamping the die.

Reference numeral 13 represents a runner through which the molten metal passes.
Reference numeral 14 denotes a plunger tip, which is connected to a cylinder (not shown) of a casting machine via an injection rod 15 and slides in the injection sleeve 4. A striker 16 is projectingly provided on the injection rod 15, and a decompression start limit switch 17 and a high-speed injection limit switch 18 are arranged at positions where the tip ends of the striker 16 can come into contact with each other by the reciprocating motion of the striker 16. ing. Runner 1 in cavity 9
A gas vent passage 20 that connects the cavity 9 and the gas outlet 19 to the outside of the mold is provided on the side opposite to where the gas vent passage 20 and the gas outlet 3 are provided. It is connected.

The movable mold 5 is provided with a communication groove 20A between the cavity 9 and the gas vent passage 20.
A sensor hole 22 is formed at 0A. Sensor hole 2
On the side wall of 2, a pressure sensor (Pirani vacuum gauge etc.) 23
Is buried. The pressure sensor 23 is connected to the control device 30, and when the measured degree of vacuum exceeds (initial value + allowable range), the degree of vacuum in the cavity 9 is judged to be insufficient, and a signal is sent to the casting machine to send the product. The product is selected as a defective product, and if further defects continue, the casting machine is stopped and an alarm is sounded. Further, the sensor hole 22 has a valve body 2 for opening and closing the opening 22a thereof so as to block the molten aluminum.
4 is provided, and the valve body 24 is connected to an advancing / retreating device 25 which is driven to advance / retreat by a signal from the control device 30.

A molten metal sensor 26 for detecting the position of the molten metal is arranged near the cavity 9 of the runner 13 of the stationary die 1, and the molten metal sensor 26 is connected to the control device 30. The molten metal sensor 26 detects the position of the molten metal of the runner 13 and sends a signal to the control device 30. Based on the signal, the control device 30 drives the advancing / retreating device 25 to retract the valve body 24 and open the opening portion. 22a is closed.

The operation of this embodiment will be described. The fixed mold 1 and the movable mold 5 are clamped by the casting machine. Next, the valve body 24 for shutting off the molten metal moves forward to move the sensor hole 22.
The opening 22a is opened. When the molten metal is poured into the injection sleeve 4, the injection rod 15 moves forward, and the plunger tip 14 closes the hot water inlet 3, the striker 16 protruding from the injection rod 15 causes the decompression start limit switch 1
7 is turned on, and the signal is transmitted to the control device 30.
A command is sent from the control device 30 to the vacuum device 21, and the vacuum device 21 discharges the air in the cavity 9 out of the mold. Furthermore, the plunger tip 14 pushes the molten metal
Pass the runner 13. When the molten metal sensor 26 is filled with the molten metal, a signal is transmitted from the molten metal sensor 26 to the control device 30, and the control device 30 sends a command to the advancing / retreating device 25 to retract the valve body 24 and open the sensor hole 22. Part 22
The pressure sensor 23 and the communication groove 20A are blocked by closing a.

When a signal is transmitted from the molten metal sensor 26 to the control device 30, at the same time, the control device 30 detects the vacuum degree (vacuum degree of the cavity 9) immediately before the sensor hole 22 is closed by the valve body 24. Is measured and the data is taken into the control device 30. Further injection rod 15
Moves forward, and striker 16 provided on injection rod 15
Turns on the high-speed injection limit switch 18, and the signal is transmitted to the control device 30. Then, the control device 30 sends a command to the casting machine to rapidly send the injection rod 15,
The plunger tip 14 forces the melt into the cavity 9 rapidly.

Next, after the molten metal is cooled and solidified, the mold is opened by a casting machine. Then, by the casting machine,
The push plate 11 is pushed in the direction of the arrow A,
Releases the cast product from the movable mold 5. If the gas vent passage 20 is clogged, the vacuuming becomes insufficient and the vacuum degree of the cavity 9 measured by the pressure sensor 23 becomes worse than (initial value + allowable range). The control device 30 determines that the pulling is insufficient and that a nest is generated inside, and selects the defective product. After releasing the cast product, a mold release agent is applied to the fixed mold 1 and the movable mold 5 by a spray device (not shown), and the mold is clamped by the casting machine. The return pin 12 is movable by the mold clamping.
Since it protrudes further, it abuts on the PL surface of the fixed mold 1 and is pushed back by the mold clamping. Therefore, the extrusion plate 11 and the extrusion pin 1
0 is pushed back together. Thereafter, the above operation is repeated, and if defective products continue, the control device 30 stops the casting machine and sounds an alarm.

According to the present embodiment, the pressure sensor is provided in the vicinity of the cavity, and the casting machine is controlled by the data of the degree of vacuum of the pressure sensor. Good products can be reduced.

In this embodiment, the sensor hole is provided on the movable die side and the pressure sensor and the molten metal cutoff mechanism are provided. However, the sensor hole may be provided on the fixed die side and the pressure sensor and the molten metal cutoff mechanism may be provided. Further, although the molten metal sensor is provided on the fixed mold side, it may be provided on the movable mold side.

[0019]

[Embodiment 2] FIG. 2 shows Embodiment 2 and is a schematic configuration diagram of a vacuum die casting apparatus. In this embodiment, the molten metal sensor of the first embodiment is replaced with a molten metal shutoff mechanism operated by a signal from a limit switch, and therefore, the same configurations are common, and the same members are designated by the same reference numerals and their description is omitted. To do.

In FIG. 2, a striker 16 is projectingly provided on the injection rod 15, and the reciprocating motion of the striker 16 makes it possible to contact the tip of the striker 16 with a limit switch 17 for starting decompression and operating the advancing / retreating device. A limit switch 27 and a high speed injection limit switch 18 are provided. Limit switch 27 for advancing and retracting device
Is disposed at a position to be turned on by the striker 16 immediately before the injection rod 15 advances and the molten metal starts filling the cavity 9. Further, the advancing / retreating device actuating limit switch 27 is connected to the control device 30, and the control device 3
0 is configured to control the pressure sensor 23 and the advancing / retreating device 25 by a signal from the advancing / retreating device differential limit switch 27.

The operation of this embodiment will be described. From where the fixed mold 1 and the movable mold 5 are clamped by the casting machine,
The decompression start limit switch 17 is turned on, and the vacuum device 2
The process up to the point where the air in the cavity 9 is discharged to the outside of the mold by 1 is the same as that in the first embodiment, and the description thereof is omitted. The molten metal is pushed in by the plunger tip 14, passes through the runner 13, and immediately before starting to fill the cavity 9,
The limit switch 27 for operating the advancing / retreating device is turned on. A signal from the limit switch 27 for operating the advancing / retreating device is transmitted to the control device 30, and the control device 30 sends a command to the advancing / retreating device 25 to retract the valve body 24 and open the opening 2 of the sensor hole 22.
2a is closed and the pressure sensor 23 and the communication groove 20A are cut off.

When a signal is transmitted from the limit switch 27 for the advancing / retreating device differential to the control device 30, the control device 3 is simultaneously operated.
For 0, the degree of vacuum immediately before the sensor hole 22 is closed by the valve body 24 is measured by the pressure sensor 25, and the data is taken into the control device 30. Further, the injection rod 15 advances, the striker 16 protruding from the injection rod 15 turns on the high-speed injection limit switch 18, and the signal is transmitted to the control device 30. Then, the control device 30 sends a command to the casting machine to rapidly send the injection rod 15, and the plunger tip 14 rapidly pushes the molten metal to fill the cavity 9.

After the molten metal is cooled and solidified, the process from the mold opening by the casting machine to the pushing back of the extruding plate 11 and the extruding pin 10 is the same as that of the first embodiment, and the description thereof is omitted. Further, as in the case of the first embodiment, the control device 30 stops the casting machine and sounds an alarm if the above-described operation is repeated and defective products continue.

According to the present embodiment, in addition to the effect of the first embodiment, the position of the molten metal is detected by the limit switch for operating the advancing / retreating device, so that the molten metal is detected for each mold as in the first embodiment. It is not necessary to provide a pressure sensor to operate, and the mold can have a simple structure.

In the present embodiment, the striker and the limit switch detect the plunger position of the casting machine. However, the present invention is not limited to this means. For example, a combination of a shield plate and a photo interrupter may be used to determine the plunger position of the casting machine. May be configured to be detected.

[0026]

Third Embodiment FIG. 3 shows a third embodiment and is a schematic configuration diagram of a vacuum die casting apparatus. In this embodiment, since the air purge mechanism is provided in the sensor hole of the vacuum die casting apparatus of the first embodiment, there are many similar configurations, and the same members are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 3, an air discharge port 28 is formed in the side wall between the opening 22a of the sensor hole 22 and the pressure sensor 23, and the air discharge port 28 is connected to a compressor 29 that delivers compressed air. The compressor 29 is a controller 30
The compressed air is sent to the air discharge port 28 in response to a command from the. Other configurations are the same as those in the first embodiment.

The operation of this embodiment will be described. A series of operations from the mold clamping, the melting point of the molten metal, the cooling, and the removal of the cast product are the same as in Example 1. After that, the advance / retreat device 25
Thus, the valve body 24 is advanced and the sensor hole 22 is opened. Next, in response to a signal from the control device 30, the compressor 29 sends compressed air to the air discharge port 28, jets the compressed air vigorously from the air discharge port 28, and the sensor hole 22 and the valve body 2
The cleaning of 4 (air purge) is performed. After that, the valve element 24 is once retracted by the advancing / retreating device 25, the sensor hole 22 is closed, the mold release is applied by the spray device (not shown), and then the mold clamping is performed. Thereafter, the above-described operation is repeated. .

According to the present embodiment, in addition to the effects of the first embodiment, the air purge prevents the valve body from closing the sensor hole due to the release agent or the aluminum dust, so that the molten metal detects the degree of vacuum. It is possible to prevent an accident, such as damage to the pressure sensor, which renders it unusable.

In the present embodiment, the vacuum die casting apparatus of the first embodiment is provided with the air purge mechanism, but the vacuum die casting apparatus of the second embodiment is also provided with the air purge mechanism, and the same effect can be obtained.

[0031]

According to the invention of claim 1, 2, 3 or 4, since the degree of vacuum of the cavity is accurately measured and a signal is transmitted to the control device, it is possible to cast a defective cast product due to a cavity or the like. It can be avoided. According to the invention of claim 2, the vacuum degree of the cavity is measured until just before the cavity is filled with the molten metal, so that accurate data of the vacuum degree can be obtained. According to the invention of claim 3, it is not necessary to provide a pressure sensor for detecting the molten metal for each mold, and the mold can have a simple structure. According to the invention of claim 4, it is possible to prevent the release of the release agent or the aluminum dust at the opening of the sensor hole, to reliably operate the molten metal blocking mechanism, and to prevent the pressure sensor from being damaged.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a vacuum die casting apparatus according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a vacuum die casting apparatus according to a second embodiment.

FIG. 3 is a schematic configuration diagram of a vacuum die casting apparatus according to a third embodiment.

FIG. 4 is a schematic configuration diagram of a conventional two-stage pressure reducing die casting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed type 5 Movable type 9 Cavity 13 Molten metal sensor 19 Gas outlet 20 Gas vent passage 20A Communication groove 22 Sensor hole 22a Opening 23 Pressure sensor 24 Valve body 25 Advancing / retracting device

Claims (4)

[Claims] 1. A cavity is formed by a fixed mold and a movable mold,
In a vacuum die casting apparatus having a gas vent passage connecting the cavity and the outside of the mold, a sensor hole is provided near the cavity of the gas vent passage, and a pressure sensor for measuring the degree of vacuum is provided on a side wall of the sensor hole. A vacuum die-casting device, characterized in that a melt blocking mechanism for opening and closing the opening of the sensor hole is provided. 2. A molten metal detecting means is provided in the vicinity of a cavity of a runner for supplying the molten metal to the cavity, the molten metal detecting means detects the molten metal and sends a signal to a control device, and the molten metal shutoff mechanism is generated by the signal of the control device. The vacuum die casting apparatus according to claim 1, wherein the vacuum die casting apparatus is configured to drive the. 3. A plunger position detecting means for detecting the plunger position of the casting machine is provided, and the plunger position detecting means detects the plunger position and sends a signal to a control device, and the melt shutoff mechanism is activated by the signal of the control device. The vacuum die casting apparatus according to claim 1, wherein the vacuum die casting apparatus is configured to be driven. 4. The vacuum die casting apparatus according to claim 1, wherein an air purging mechanism having an air discharge port is provided between the opening of the sensor hole and the pressure sensor.