JP2020192602A - Degasser for vacuum die casting - Google Patents

Abstract

To provide a degasser for vacuum die casting allowing for externally grasping a manner or state of opening/closing of a closing valve together with drastic decrease of leakage of nearly all of polluted gas and of fraction defective, extended service time of degasser components and productivity improvement.SOLUTION: A degasser for vacuum die casting includes an electromagnetic valve 11 that is provided on a vacuum sucker side of an air-discharge pipe 14 supplying air to closing means 8, a closing valve-sided air-supply passage 9 and a closing valve-sided air-discharge passage 10 that are provided communicating with a space 51 of a closing valve 5, and a valve open-close indicator 13 that is attached to the closing valve-sided air-supply passage 10 to indicate an open/close state of the closing valve 5. Furthermore, the valve open-close indicator 13 consists at least of an indication rod 131 that projects due to the air pressure of the space 51 of the closing valve 5, an outer cylinder 132 that slidably incorporates the indication rod 131, and a lid 133 that is attached at a tip of the outer cylinder 132 and prevents the indication rod 131 from falling out.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vacuum die-casting degassing device in which gas, fine dust, etc. generated when a molten metal enters a cavity is sucked together with air by a vacuum suction device and discharged to the outside through an exhaust passage thereof. ..

As shown in FIG. 1 (b), a general die-cast degassing device includes an exhaust passage (3) communicating with a cavity between a fixed block (1) and a movable block (2), and the fixed block (1). ), A pressure receiving valve (4) arranged on the inlet side of the exhaust passage (3), a closing valve (5) arranged on the outlet side, and an opening / closing lever for transmitting the operation of the pressure receiving valve (4) to the closing valve (5). (6) is provided, and the closing valve (5) is forcibly closed by the opening means (7) that presses the closing valve (5) in the opening direction and the opening / closing lever (6) during the initial operation when the mold is cold. It is provided with at least a closing means (8).

At this time, the pressure receiving valve (4) that receives the pressure of the molten metal entering from the inlet side of the degassing device that communicates with the cavity and the closing valve (5) that closes via the opening / closing lever (6) slide between them. Aluminum and fine dust get into the gaps of the parts and get dirty easily, and if fine dust gets into the gaps of the sliding parts, the movements of both valves (4) and (5) become slow and the pressure receiving valves (4) move slowly. As a result, the closing function of the closing valve (5) was likely to deteriorate. Moreover, if the molten metal enters the closing valve (5) due to the leading phenomenon of the molten metal before the closing valve (5) is closed, a failure occurs and the casting operation is interrupted. In addition, the molten metal becomes cold while it passes through the cavity and reaches the degassing device that communicates with it, and the cooled molten metal tends to cling to metal. Therefore, the pressure receiving valve (4) and the closing valve (5) Hugging is likely to occur in the sliding part of the aluminum, and if the hugging part occurs in the gap of the sliding part, the degassing device and the vacuum suction tool device will break down, and the casting work will be interrupted each time. However, aluminum had to be removed. Further, if fine dust or the like enters the vacuum suction device from the sliding portion of the closing valve (5), it causes a failure of the vacuum suction device itself and also causes a problem that the filter is clogged, so that the casting work is temporarily interrupted. I had to. The valve method for closing the closing valve (5) by the molten metal pressure as described above is hereinafter referred to as a "shutdown method" in the present invention.

On the other hand, in the shut-off type degassing device using the shut-off valve, as shown in FIG. 4, the cavity in the mold is filled with molten metal by an injection plunger, and the vacuum provided in the vacuum line system communicating with the cavity is provided. The switching valve is opened, and the molten metal is pressure-molded while sucking the gas generated in the cavity. At this time, when the detection unit of the injection plunger comes to the point C in the figure, the vacuum switching valve is opened and the degassing operation of the gas generated in the cavity is started. When the detection part of the injection plunger comes to point A in the figure, the molten metal is completely filled and the shut-off valve is closed, but the gas is exhausted before it is closed, and aluminum and other substances other than gas are discharged. The current situation was that the valve was stopped in front of the shut-off valve. In this case, a particularly expensive detection device for electrically detecting the molten metal is required, and a large-scale device is required as shown in FIG.

However, the conventional one is a shut-off valve due to the variation in the time from the closing position signal to the actual valve closure, the electrical signal response time, or the change in the timing of the molten metal flow in the mold due to the variation in the amount of hot water supplied. Aluminum and fine dust get into the gaps of the sliding parts and it is easy to get dirty, and if fine dusts get into the gaps of the sliding parts, the shut-off valve will not move well, and if the movement slows down, the shut-off valve will It was easy to result in a decrease in the closing function. At this time, it can be dealt with by closing the shut-off valve earlier, but if it is done earlier, all the dirty gas cannot be completely removed, which may cause gas entrainment and make it difficult to improve the quality of the die-cast product. There was a risk of increasing the defect rate.
Moreover, if the molten metal enters the shut-off valve due to the leading phenomenon of the molten metal before the shut-off valve is closed, a failure occurs and the casting work is interrupted. In addition, the molten metal becomes cold while it passes through the cavity and reaches the degassing device that communicates with it, and the cooled molten metal tends to cling to metal, so it clings to the sliding part of the shut-off valve. If a hugged portion is formed in the gap of the sliding portion, a failure occurs. Therefore, the casting operation must be interrupted each time to remove the aluminum or the like that has entered. As a result, it took a lot of time to remove the aluminum and the like that had entered and to restore the casting work.

Patent No. 6408845 JP-A-2017-08755

As mentioned above, conventional shut-off and shut-off products are prone to clogging of valves, etc., so be sure to disassemble the degassing device each time you start casting, and then the outer peripheral surface of the valve and the movable block. It was troublesome because the hole on the side had to be cleaned. In addition, the life of sliding parts is short, it is necessary to replace them, the productivity of die-cast products is low, and maintenance costs are high. Further, the open / closed state of the closing valve could not be confirmed from the outside.

An object of the present invention is to provide a degassing device for vacuum die casting in which substantially all of the dirty gas is released, the defective rate is drastically reduced, the parts of the degassing device last a long time, and the productivity is improved.

Another object of the present invention is to provide a degassing device for vacuum die casting in which the opening / closing state and state of a closing valve can be known from the outside.

The present invention has been made in view of the above situation, and has a structure in which a shut-off function is added to the shutdown method. That is, an electromagnetic valve is provided on the vacuum suction device side of the air supply pipe that supplies air to the closing means. Further, a closed valve side air supply path and a closed valve side exhaust path communicating with the space of the closed valve are provided, and a valve open / close indicator for displaying the open / closed state of the closed valve is attached to the closed valve side air supply path. Further, the valve open / close indicator is attached to a display rod protruding by the air pressure in the space of the closing valve, an outer cylinder in which the display rod is slidably incorporated, and the tip of the outer cylinder, and the display rod comes out. Use a lid that prevents it from occurring, and at least one that is composed of. Furthermore, it is preferable to have a structure in which a timer for operating and opening the solenoid valve is connected to the solenoid valve.

In the shutdown type vacuum die casting degassing device as in claim 1, an air supply pipe (14) in which air is supplied to the closing means (5) in order to add a shut-off function to the closing means (8). By providing the solenoid valve (11) on the vacuum suction device side of), the present invention is a method in which a shut-off function is added. Therefore, the closing valve (5) can be reliably closed, and even if the molten metal of the preceding run flows in before the pressure receiving valve (4) operates and before reaching the closing valve (5). , The inflow to the vacuum suction device side can be prevented by closing the closing valve (5). Therefore, almost all the dirty gas is released, the defective rate is drastically reduced, the parts of the degassing device and the vacuum suction device last longer, and the productivity is improved. Moreover, it has a shut-off function even though it does not require a large-scale capital investment as in the conventional shut-off method.

The closed valve side air supply passage (9) and the closed valve side exhaust passage (10) communicating with the space portion (51) of the closed valve (5) are provided as in claim 2, and the closed valve side exhaust passage (10) is provided. By installing a valve open / close indicator (13) that displays the open / closed state of the closed valve (5), the open / closed state and state of the closed valve (5) can be known from the outside, so the next die can be used without disassembling one by one. It is possible to start the casting work of the cast product quickly.

As shown in claim 3, the valve open / close indicator (13) is slidable between the indicator bar (131) protruding by the air pressure of the space (51) of the closed valve (5) and the indicator bar (131). The structure is simple because it is composed of at least an outer cylinder (132) built into the unit and a lid (133) that is attached to the tip of the outer cylinder (132) and prevents the display rod (131) from coming off. Moreover, it is easy to manufacture. Further, the operation of the closing means (8) at the time of trial injection when the molten metal pressure is low can be confirmed in the protruding state of the display rod (131).

As shown in claim 4, by connecting the timer (15) for operating and opening the solenoid valve (11) to the solenoid valve (11), the shutdown method has a shut-off function and the timer. (15) makes it possible to adjust the time from the injection start time to the closing of the closing valve (5).

It is explanatory drawing which shows the main part of the Embodiment of this invention. It is explanatory drawing which shows the operation of the pressure receiving valve, the closing valve and the middle valve of this embodiment. It is explanatory drawing which shows the operation of the valve open / close indicator of this embodiment. It is explanatory drawing which shows the main part of the conventional vacuum die casting apparatus.

FIG. 1 is a diagram showing an embodiment of the present invention, in which a fixed block (1) is provided with a closed valve side air supply passage (9) and a closed valve side exhaust passage (10), which will be described later. 1 (a) is a view from above of the fixed block (1) with the movable block (2) of the degassing device removed, and FIG. 1 (b) shows a cross section of the degassing device.

Next, when each number is described with reference to FIG. 1, (1) is a fixed block and (2) is a movable block. (3) is an exhaust passage formed between the fixed block (1) and the movable block (2) and communicating with the cavity. (4) is a pressure receiving valve arranged on the inlet side of the exhaust passage (3), and the pressure receiving valve (4) is arranged in the fixed block (1) and can move up and down.

(5) is a closing valve arranged on the outlet side of the exhaust passage (3), and the closing valve (5) is arranged in the fixed block (1) and can move up and down. The structure for closing and opening the exhaust passage (3) by the closing valve (5) is not limited to the above, and other structures may be used.

(6) is a swingable opening / closing lever provided for transmitting the operation of the pressure receiving valve (4) to the closing valve (5). Reference numeral (7) is an opening means for lifting the opening / closing lever (6), and a coil spring may be used as the opening means (7). The opening / closing lever (6) is pressed in the opening direction of the closing valve (5) to open the closing valve (5). The opening means (7) is not limited to the coil spring, and an air cylinder or the like may be used.

(8) is a closing means for forcibly pressing the opening / closing lever (6) in the closing direction of the closing valve (5) during the initial operation, and the closing means (8) has a shut-off function, and this function. Uses a structure that pushes down the middle valve (81) by the air pressure from the solenoid valve (11) described later. (9) is a closed valve side air supply passage that communicates with the space portion (51) of the closed valve (5), and (10) is a closed valve side exhaust passage that communicates with the space portion (51) of the closed valve (5). [See Fig. 1 (a)].

(11) is a solenoid valve provided on the vacuum suction device side of the air supply pipe (14) to which air is supplied, and the solenoid valve (11) changes the pressure of the injection blanker of the casting machine from low pressure to high pressure. The closing valve (5) serves to close by receiving and operating the signal at the time of switching, and the solenoid valve (11) having an air supply port and an exhaust port is used. Further, the solenoid valve (11) presses the middle valve (81) with air to forcibly close the closing valve (5).
On the other hand, the structure may be such that the timer (15) described later is connected to the solenoid valve (11), and the solenoid valve (11) is operated by the timer (15).

(12) is a back plate attached to the bottom surface of the fixed block (1) shown in FIG. 1 (b). Reference numeral (13) is a valve open / close indicator attached to the back plate (12) by communicating with the closed valve side exhaust passage (10), and the valve open / close indicator (13) is shown in FIG. 1 (b). In addition, a display rod (131) protruding by the air pressure of the space portion (51) of the closing valve (5), an outer cylinder (132) in which the display rod (131) is slidably built in, and the outer cylinder (the outer cylinder). There is at least a lid (133) that is attached to the tip of 132) and prevents the display bar (131) from coming off. The valve open / close indicator (13) is for displaying the open / closed state of the closed valve (5), and the valve open / close indicator (13) is installed so that the outer cylinder (132) stands vertically when in use. Install to install. Further, it is preferable to provide packing (not shown) on the contact surface between the back plate (12) and the outer cylinder (132) and the contact surface between the end surface of the outer cylinder (132) and the lid (133). Further, it is preferable that the valve open / close indicator (13) is provided with a detector (not shown) capable of detecting the entry / exit of the indicator bar (131). (14) is an air supply pipe that supplies air to the closing means (8), (15) is a timer, and the timer (15) can be opened by operating the solenoid valve (11). All you need is. The timer (15) is not always necessary.

Next, the operation of the present invention will be described with reference to FIG. When casting is first started, the molten metal enters the cavity, gas is generated, and the molten metal is discharged to the exhaust side together with the air inside the cavity, and the cavity is filled with the molten metal.
At this time, the solenoid valve (11) transmits at the time of switching, based on the signal from the operation unit of the casting machine shown in FIG. 4, that is, the signal when the pressure of the injection brander switches from low pressure to high pressure. When the signal is transmitted back and forth and the control unit of the vacuum suction device receives the signal, the control unit issues a command to operate and open the solenoid valve (11). Then, air is discharged from the air supply port of the solenoid valve (11), compressed air such as a compressor (not shown) flows into the space above the middle valve (81), and the middle valve (81) is pushed downward to open and close. The closing valve (5) is closed via the lever (6) as shown in FIG. 2A. Therefore, the closed valve (5) is prevented from being clogged due to the molten metal running ahead.

On the other hand, the operation of the solenoid valve (11) to close the closing valve (5) by another method will be described. In this case, the timer (15) is connected to the solenoid valve (11), and the operation of the solenoid valve (11) receives a signal from the operation unit of the casting machine, that is, an injection start signal. After that, the time until the display rod (131) of the valve open / close indicator (13) is pulled in from the protruding state is automatically measured and recorded manually or by the control unit of the vacuum suction device or the operation unit of the casting machine. This measurement is repeated several times to obtain an average value, and the average value is manually or automatically set in the timer (15). After that, at the set time from the reception of the injection start signal, the closing valve (5) is closed by the operation of the solenoid valve (11). To start counting the timer (15), the injection start signal from the operation unit of the casting machine is received by the control unit of the vacuum suction device or the operation unit of the casting machine, and the set time is counted by the timer (15). When this is completed, a program (not shown) is set in the control unit or operation unit in advance so that a signal for operating the solenoid valve (11) is transmitted.

FIG. 2B is a diagram showing a case where the shutdown method is activated before the shutoff function is activated, and this will be described. In the shut-off method, the shutdown-type degassing device (9) operates when it is not possible to deal with the occurrence of the first-running hot water. That is, when the molten metal comes near the upper surface of the pressure receiving valve (4), the pressure of the molten metal is applied to the pressure receiving valve (4) and the molten metal is pushed downward, and the closing valve (5) is closed via the opening / closing lever (6). To. For this reason, all the dirty gas is exhausted, the defective rate of the die-cast product is lowered, the parts of the degassing device and the vacuum suction device last longer, and the productivity is improved.

Next, the operation of the valve open / close indicator (13) of the present invention will be described with reference to FIG. First, when the molten metal enters from the inlet side of the exhaust passage (3) and comes near the upper surface of the pressure receiving valve (4), the middle valve (81) is pressurized and operates. At this time, air is supplied to the closed valve side air supply passage (9) provided in the closed valve (5) and exhausted from the closed valve side exhaust passage (10). Therefore, while the closing valve (5) is open, air is discharged from the closing valve side exhaust passage (10), and the air is discharged from the outer cylinder (132) as shown by the white arrow shown in FIG. 3 (b). The display rod (131) is slid, and the tip of the display rod (131) protrudes from the lid (133). After that, when the closing valve (5) is closed by the shutdown method or the shut-off method, the space (51) disappears, the air exhaust from the closing valve side exhaust passage (10) disappears, and the air becomes the outer cylinder ( By preventing the flow into the inside of 132), the display bar (131) is returned to its original position by its own weight, the display bar (131) is retracted, and the display bar (131) is almost eliminated. Therefore, if the display bar (131) protrudes as shown in FIG. 3 (b), it indicates that the closing valve (5) is open, and if it does not protrude as shown in FIG. 3 (a), the closing valve (5) is displayed. It can be confirmed at a glance from the outside that (5) is in a closed state.

As described above, the present invention is effective for the low-speed filling die casting method (squeeze die casting method, etc.) because the shut-off function is added to the shutdown method and the solenoid valve (11) operates at each injection during normal operation. Yes, there is no need for low-speed, high-speed (no boosting) operation such as throwing away, which was conventionally done, and the test firing required in the shutdown method, that is, the closing valve at the time of test run before the mold warms up. The work of forcibly closing (5) is also unnecessary.
In addition, the impact of the opening / closing lever (6) affected by the pressure receiving valve (4) in the shutdown method was quite large, and metal fatigue of the opening / closing lever (6) was likely to occur, but a shut-off function should be added. As a result, the durable life of the opening / closing lever (6) is dramatically improved.
As a result, in the present invention, the valve clogging of the dirty gas due to the leading hot water is almost completely prevented, and the regular maintenance period of the degassing device (9) and the vacuum suction device is more than doubled as compared with the conventional case. It became possible to extend it.

1 Fixed block 2 Movable block 3 Exhaust passage 4 Pressure receiving valve 5 Closing valve
51 Space 6 Open / close lever 7 Opening means 8 Closing means 9 Closing valve side air supply path
10 Closed valve side exhaust passage
11 Solenoid valve
13 Valve open / close indicator
131 Display bar
132 Outer cylinder
133 Lid
14 Air supply pipe
15 timer

Claims (4)

A pressure receiving valve (4) having an exhaust passage (3) communicating with the cavity between the fixed block (1) and the movable block (2) and being arranged on the inlet side, and a closing valve (5) arranged on the outlet side. An opening / closing lever (6) that transmits the operation of the pressure receiving valve (4) to the closing valve (5), an opening means (7) that presses the closing valve (5) in the opening direction, and the opening / closing lever (6). In a vacuum die casting degassing device including at least a closing means (8) that presses the closing valve (5) in the closing direction, the air supply pipe (14) that supplies air to the closing means (8). A degassing device for vacuum die casting, characterized in that an electromagnetic valve (11) is provided on the vacuum suction device side. The closed valve side air supply passage (9) and the closed valve side exhaust passage (10) communicating with the space portion (51) of the closed valve (5) are provided, and the closed valve side exhaust passage (10) is provided with the closed valve. The degassing device for vacuum die casting according to claim 1, wherein the valve open / close indicator (13) for displaying the open / closed state of (5) is attached. An outer cylinder in which the valve open / close indicator (13) slidably incorporates a display rod (131) protruding by the air pressure of the space (51) of the closure valve (5) and the display rod (131). The vacuum die casting gas according to claim 2, which is composed of (132) and a lid (133) attached to the tip of the outer cylinder (132) and preventing the display rod (131) from coming off. Extractor. The degassing device for vacuum die casting according to claim 1, wherein a timer (15) for operating and opening the solenoid valve (11) is connected to the solenoid valve (11).