JP2022182185A - Valve device and die-casting device - Google Patents

Abstract

To obtain a valve device which can improve an intrusion prevention performance of molten aluminum into a vacuum circuit by speedily blocking the intrusion of the molten aluminum into the vacuum circuit.SOLUTION: A valve device comprises a valve body 1 which is opened and closed by separating from, and contacting with a valve seat 2, and an air cylinder 6 for driving the valve body 1 by a pneumatic pressure in an opening/closing direction. The air cylinder 6 has a piston 4 fixed to the valve body 1, and a housing 5 having a cylinder chamber 60 in which the piston 4 is accommodated, and the piston 4 has a first seal part 13 which can slide with respect to a first slide face 8 at an internal peripheral face of the cylinder chamber 60, and a second seal part 14 which is slidably arranged at a second slide face 9 having an inside diameter which is smaller than that of the first slide face 8. The cylinder chamber 60 is partitioned to a first space 16 near the valve body 1 rather than the first seal part 13, and a second space 17 at a side apart from the valve body 1 rather than the first seal part 13, and at a side near the valve body 1 rather than the second seal part 14, and the valve body 1 is driven by the pneumatic pressure in the first space 16 and the pneumatic pressure in the second space 17.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vacuum valve device and a die casting apparatus having the vacuum valve device.

In a vacuum valve device used in a die casting apparatus, air in the mold is sucked by a vacuum tank connected to the mold via a vacuum valve during the process of filling the mold with molten aluminum. However, if the vacuum valve is open when the mold is completely filled with molten aluminum, the molten aluminum will enter the vacuum circuit and destroy the vacuum circuit. must be used to protect the vacuum circuit.

Concretely, the shutoff of the valve is a structure that shuts off the poppet valve in the vacuum valve by the backward movement of the air cylinder via the valve shaft directly connected to the piston in the air cylinder.

In the technique described in Patent Document 1, when the piston is moved in the gas release direction (cavity opening direction) with one directional control valve, the first space (rod side) is opened with one directional control valve to release the pressure. to supply air to the second space (head side).

When moving the piston in the cavity closing direction, one directional control valve supplies air to the first space (rod side) and opens the second space (head side) to reduce the pressure.

Japanese Patent Publication No. 3-5901

In die casting, the time required to fill the mold with molten aluminum is as short as about 30 to 100 ms, so shutting off the valve is completed within 10 ms after the command signal to shut off the valve is sent, resulting in high-speed responsiveness. Desired.

There is a time lag between when a valve shutoff signal is input to the directional control valve, the directional control valve operates, and the operation control state is changed. There is a demand for a technique that shortens this time lag, shuts off the vacuum valve device at a higher speed, and improves the performance of preventing molten aluminum from entering the vacuum circuit.

SUMMARY OF THE INVENTION An object of the present invention is to realize a valve device and a die-casting device capable of rapidly shutting off molten aluminum from entering the vacuum circuit and improving the performance of preventing molten aluminum from entering the vacuum circuit.

In order to achieve the above object, the present invention is configured as follows.

A valve device comprising a valve body that opens and closes by contacting and separating from a valve seat, and an air cylinder that drives the valve body in an opening and closing direction by air pressure, wherein the air cylinder includes a piston fixed to the valve body. and a housing having a cylinder chamber in which the piston is accommodated, wherein the piston is provided with a first seal portion slidably provided on a first sliding surface on the inner peripheral surface of the cylinder chamber. and a second seal portion slidably provided on a second slide surface having an inner diameter smaller than that of the first slide surface, wherein the cylinder chamber is more likely to be slidable on the second slide surface than the first seal portion. partitioned into a first space on the side closer to the valve body and a second space on the side farther from the valve body than the first seal portion and closer to the valve body than the second seal portion; The valve body is driven by the air pressure in the first space and the air pressure in the second space.

According to the present invention, it is possible to realize a valve device and a die-casting device capable of rapidly shutting off molten aluminum from entering the vacuum circuit and improving the performance of preventing molten aluminum from entering the vacuum circuit.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional block diagram of the valve apparatus which concerns on Example 1 of this invention. FIG. 4 is a diagram showing a control unit that controls operations of a directional control valve, a high-speed exhaust valve, and a display unit; FIG. 5 is an explanatory diagram of how the piston is moved by the operation of the directional control valve and the high-speed exhaust valve in the air cylinder of Example 1; FIG. 5 is an explanatory diagram of how the piston is moved by the operation of the directional control valve and the high-speed exhaust valve in the air cylinder of Example 1; FIG. 5 is an explanatory diagram of how the piston is moved by the operation of the directional control valve and the high-speed exhaust valve in the air cylinder of Example 1; FIG. 5 is an explanatory diagram of how the piston is moved by the operation of the directional control valve and the high-speed exhaust valve in the air cylinder of Example 1; It is an example of an air cylinder different from the present invention, and is a diagram showing an example for comparison with Example 1 of the present invention. FIG. 8 is an operation explanatory diagram of an air cylinder in the example shown in FIG. 7 different from the present invention; FIG. 7 is an explanatory view of the operation of the air cylinder shown in FIGS. 3 to 6 in Embodiment 1 of the present invention; FIG. 2 is an explanatory diagram of the proximity sensor shown in FIG. 1; FIG. 2 is an explanatory diagram of the proximity sensor shown in FIG. 1; It is a schematic block diagram of Example 2 of this invention, and is explanatory drawing of the die-casting apparatus to which this invention was applied.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional configuration diagram of a valve device according to Embodiment 1 of the present invention.

In FIG. 1, a valve body 1 (rod) is in contact with and separates from a valve seat 2 to form a poppet valve 19 for breaking vacuum. By opening and closing the vacuum cut-off poppet valve 19, air flow is formed and cut off to prevent molten aluminum from entering the vacuum circuit.

The valve body 1 has a valve shaft 3, a piston 4 is fixed to the valve shaft 3 of the valve body 1, the piston 4 is arranged in a cylinder housing 5, and an air cylinder 6 is formed. The air cylinder 6 drives the valve body 1 in the opening/closing direction by air pressure. The piston 4 and the valve body 1 are integrally formed, and the valve body 1 moves as the piston 4 moves.

The piston 4 is moved by the operation of the directional control valve 10 and the high speed exhaust valve 11 . The pneumatic control circuit 20 includes a directional control valve 10 , a high speed exhaust valve 11 and an exhaust silencer 12 . The air cylinder 6 has a piston 4 fixed to the valve body 1 and a housing (cylinder housing) 5 having a cylinder chamber 60 in which the piston 4 is accommodated.

The proximity sensor 7 is a sensor that detects approach to the rear end of the piston 4 (right end in FIG. 1). The proximity sensor 7 is arranged at a position close to and facing the end side surface of the valve body 1 extending through the third space 18 open to the atmosphere, and detects the open/closed position of the valve body 1 .

A first seal portion 13, a second seal portion 14 and a third seal portion 15 are formed in the cylinder housing 5, and a first space 16, a second space 17 and a third space 18 are formed. The cylinder housing 5 has a third seal portion 15 that slidably holds the valve body 1 .

The piston 4 moves while sliding on the inner surface of the cylinder housing 5 by the first sliding surface 8 and the second sliding surface 9 . The diameter of the second seal portion is larger than the diameter of the third seal portion 15 .

The piston 4 has a first seal portion 13 slidably provided on a first sliding surface 8 on the inner peripheral surface of the cylinder chamber 60 and a second sliding portion 13 having an inner diameter smaller than that of the first sliding surface 8 . and a second seal portion 14 provided slidably with respect to the surface 9 .

The first seal portion 13 is slidably provided on the first sliding surface 8 on the inner peripheral surface of the cylinder chamber 60 , and the second seal portion 14 has a smaller inner diameter than the first sliding surface 8 . 2 is slidably provided on the sliding surface 9 .

The cylinder chamber 60 consists of a first space 16 closer to the valve body 1 than the first seal portion 13 and a space further from the valve body 1 than the first seal portion 13 and farther than the second seal portion 14 . 1 and a third space 18 farther from the valve body 1 than the second seal portion 14 .

The air pressure in the first space 16 and the air pressure in the second space 17 drive the valve body 1 .

The directional control valve 10 can switch between pressurizing and depressurizing the first space 16 . The direction control valve 10 can also switch between pressurizing and depressurizing the second space 17 . While the directional control valve 10 switches the pressure of the second space 17 from pressurization to pressure reduction, the high-speed exhaust valve depressurizes the second space.

The high-speed exhaust valve 11 can switch between blocking and opening the second space 17 .

FIG. 2 is a diagram showing the control section 22 that controls the operations of the directional control valve 10, the high-speed exhaust valve 11, and the display section 23. As shown in FIG. The control unit 22 and the display unit 23 are omitted in FIG.

The operations of the directional control valve 10 and the high-speed exhaust valve 11 described with reference to FIG. 2 are controlled by the controller 22 .

3 to 6 are explanatory diagrams showing how the piston 4 is moved by the operation of the directional control valve 10 and the high-speed exhaust valve 11 in the air cylinder 6 of the first embodiment.

In the state shown in FIG. 3, the directional control valve 10 is moved rightward, the air from the air source 21 is supplied to the second space 17 through the directional switching valve 10, and the first space 16 is connected to an exhaust silencer 12 via a directional control valve 10 . The high-speed exhaust valve 11 has been moved to the right and is in a closed state.

As a result, a leftward force acts on the piston 4, and the valve body 1 moves in the opening direction.

The third space 18 is open to the atmosphere. This causes the piston 4 to move rightward.

In the state shown in FIG. 3, the directional control valve 10 is moved leftward, the air from the air source 21 is supplied to the first space 16 through the directional control valve 10, and the second space 17 is connected to the exhaust silencer 12 via the directional control valve 10 and is connected to the exhaust silencer 12 via the high speed exhaust valve 11 .

The third space 18 is open to the atmosphere. This causes the piston 4 to move rightward.

Next, in FIG. 4, the directional control valve 10 and the high-speed exhaust valve 11 move leftward. Since the high-speed exhaust valve 11 operates earlier than the directional control valve 10, the second space 17 is exhausted via the high-speed exhaust valve 11, and the pressure P1 begins to drop.

Next, in FIG. 5, the directional control valve 10 and the high-speed exhaust valve 11 move leftward from the state in FIG. Air from an air source 21 is supplied to the first space 16 through the directional control valve 10, the second space 17 is connected to the high speed exhaust valve 11 and the exhaust silencer 12, and the pressure P1 in the second space 17 is As it lowers, the piston 4 moves to the right (the direction in which the valve body 1 opens).

Next, in FIG. 6, the piston 4 moves further to the right from the state shown in FIG. 5 until the left end face of the piston 4 touches the inner wall of the cylinder chamber 60 and stops moving.

FIG. 7 is an example of an air cylinder 6A different from the present invention, and is a diagram showing an example for comparison with Example 1 of the present invention.

In the state shown in FIG. 7, the directional control valve 10 is moved leftward, air from the air source 21 is supplied to the first space 16 through the directional switching valve 10, and the second space 17 is connected to an exhaust silencer 12 via a directional control valve 10 . This causes the piston 4 to move rightward.

Next, the operation of moving the piston 4 to the right from the state shown in FIG. 7 and then to the left from that state will be described.

The directional control valve 10 is moved rightward in FIG. 7, and the air supplied from the air source 21 is supplied to the second space 17 via the directional control valve 10 .

The first space 16 is open toward the exhaust silencer 12 because the directional control valve 10 is moved rightward. This causes the piston 4 to move leftward. Then, it returns to the state shown in FIG.

FIG. 8 is an explanatory view of the operation of the air cylinder 6A in the example shown in FIG. 7 which is different from the present invention, where the vertical axis indicates air pressure [MPa] and the horizontal axis indicates time [ms].

FIG. 9 is an explanatory view of the operation of the air cylinder 6 shown in FIGS. 3 to 6 in Embodiment 1 of the present invention, where the vertical axis indicates air pressure [MPa] and the horizontal axis indicates time [ms]. show.

In FIG. 8, the moment when the valve shutoff signal is input is the shutoff signal input time point T0, and the moment when the directional control valve is switched to the reverse operation control is time point T1. In the case of the air cylinder 6A shown in FIG. 7, the pneumatic circuit (not shown) of the direction control valve 10 is switched from time T1, the exhaust of the second space 17 is started, and the pressure P2 in the second space 17 is decreased. continue.

At the same time, the first space 16 is pressurized, the pressure P1 in the first space 16 increases, and a force pushing the piston 4 in the backward direction (from left to right in FIG. 4) is generated.

When this pressure P1 exceeds the force pushing the piston 4 forward (from right to left in FIG. 4) by the pressure P2, the piston 4 begins to retreat (indicated by a thick solid line rising from time T2).

During the retraction movement of the piston 4, the pressures P1 and P2 are in equilibrium. At the retraction operation completion time T3, which is the retraction limit of the piston 4, the pressure P1 increases to the supply pressure of the air source 21 and is maintained. Also, the pressure P2 becomes the atmospheric pressure. (Time points T4 to T5).

In contrast to the example shown in FIG. 7, in the first embodiment of the present invention, as shown in FIG. , serves to assist the evacuation of the second space 17 via the directional control valve 10 (time T1'). For example, if it takes 3 ms to time T1, time T1' is about 1 ms.

Since the volume of the second space 17 is reduced by the third space 18 (atmospheric open state) in the first embodiment of the present invention, the exhaust time of the second space 17 is shortened compared to the example shown in FIG. (Time T2 shown in FIG. 9 is shorter than time T2 shown in FIG. 8).

Furthermore, since the third seal portion 15 reduces the cross-sectional area of the second space 17 that receives the force acting by the pressure P2, the piston 4 moves to the retraction movement with less force than when the third seal portion 15 does not exist. be able to.

The reverse motion completion time T3 in the operation of the first embodiment of the present invention shown in FIG. 9 is shorter than the reverse motion completion time T3 shown in FIG. In other words, the time from the cut-off signal input time T0 to the reverse operation completion time T3 is shorter in the first embodiment (FIG. 9) than in the comparative example (FIG. 8).

According to the first embodiment, the above-described operations and actions can shorten the time from input of the disconnection signal T0 to completion of the retraction operation T3, thereby realizing high-speed disconnection of the poppet valve 19 for vacuum disconnection.

10 and 11 are explanatory diagrams of the proximity sensor 7 shown in FIG.

FIG. 10 is an enlarged view of the vicinity where the proximity sensor 7 is arranged in the valve device of the present invention, showing the forward limit position (valve open) of the valve body 1. As shown in FIG.

FIG. 11 is an enlarged view of the vicinity of the proximity sensor 7 in the valve device of the present invention, showing the retraction limit position (valve closed) of the valve body 1. As shown in FIG.

The proximity sensor 7 detects the distance from the valve body 1 from the forward limit position (valve open) of the valve body 1 to the backward limit position (valve closed), and supplies a detection signal to the controller 22 . Based on the detection signal supplied from the proximity sensor 7 , the control unit 22 measures the operation time from the forward limit position (valve open) to the backward limit position (valve closed) of the valve body 1 .

Then, the control unit 22 determines whether or not the reverse time, which is the timed operation time from the forward limit position (valve open) to the reverse limit position (valve closed) of the valve body 1, is within a specified time (monitoring). do).

If the retraction time of the valve body 1 is not within the specified time, it is determined that an abnormality has occurred in the valve device, and an alarm is output to the display section 23 .

As a result, the occurrence of an abnormality in the valve device is automatically detected, and an alarm is output, thereby enabling early detection of the abnormality.

As described above, according to the first embodiment of the present invention, there is provided a valve device capable of rapidly shutting off molten aluminum from entering the vacuum circuit and improving the performance of preventing molten aluminum from entering the vacuum circuit. can be realized.

Furthermore, according to the first embodiment of the present invention, it is possible to detect the occurrence of abnormality in the valve device at an early stage.

(Example 2)
Next, Example 2 of the present invention will be described.

FIG. 12 is a schematic block diagram of Embodiment 2 of the present invention, and is an explanatory diagram of a die casting apparatus 24 to which the present invention is applied.

In FIG. 12, the die casting apparatus 24 includes a mold 33 having a cavity 26 of a predetermined shape, a hot water supply section 27 for pumping molten metal into the cavity 26, and a vacuum valve device 23 for exhausting the air in the cavity 26. Prepare.

The hot water supply unit 27 also includes an injection sleeve 29 for injecting molten aluminum (AL molten metal) 30 from the injection sleeve 29 into the cavity 26 .

The inside of the vacuum tank 31 is evacuated by the vacuum pump 32 , sucks the air in the cavity 26 through the vacuum valve device 25 , and fills the cavity 26 with the molten aluminum 30 .

The vacuum valve device 25 is the valve device according to the first embodiment.

The vacuum valve device 25 sucks the air in the mold 33 by the vacuum tank 31 connected to the mold 33 via the vacuum valve device 25 in the process of filling the cavity 26 with the molten aluminum 30 in the mold 33 . do.

However, if the vacuum valve device 25 is open when the mold 33 is completely filled with the molten aluminum 30, the molten aluminum 30 will enter the vacuum circuit and break the vacuum circuit. Immediately before completion, it is necessary to shut off the vacuum valve device 25 to protect the vacuum circuit.

In die casting, the time required to fill the mold 33 with the molten aluminum 30 is very short, about 30 to 100 ms. responsiveness is required.

The vacuum valve device 25 to which the valve device according to the first embodiment of the present invention is applied cuts off the entry of the molten aluminum 30 into the vacuum circuit at high speed, thereby improving the performance of preventing the entry of the molten aluminum 30 into the vacuum circuit. can be realized.

DESCRIPTION OF SYMBOLS 1... Valve body 2... Valve seat 3... Valve shaft 4... Piston 5... Cylinder housing 6... Air cylinder 7... Proximity sensor 8. First sliding surface 9 Second sliding surface 10 Directional control valve 11 High-speed exhaust valve 12 Exhaust silencer 13 First seal 14. Second seal 15 Third seal 16 First space 17 Second space 18 Third space 19 Poppet valve for breaking vacuum 20. Air pressure control circuit 21 Air source 22 Control unit 23 Display unit 24 Die casting device 25 Vacuum valve device 26 Cavity 27 Hot water supply unit 28 Injection plunger 29 Injection sleeve 30 Molten aluminum 31 Vacuum tank 32 Vacuum pump 60 Cylinder chamber

Claims (7)

A valve device comprising: a valve body that opens and closes by contacting and separating from a valve seat; and an air cylinder that drives the valve body in an opening and closing direction by air pressure,
The air cylinder has a piston fixed to the valve body and a housing having a cylinder chamber in which the piston is accommodated,
The piston has a first seal portion slidably provided on a first sliding surface on the inner peripheral surface of the cylinder chamber, and a second sliding surface having an inner diameter smaller than that of the first sliding surface. a second seal portion slidably provided with respect to the
The cylinder chamber includes a first space on a side closer to the valve body than the first seal portion, and a space on a side farther from the valve body than the first seal portion and the valve body than the second seal portion. and a second space on the side closer to the
A valve device in which the valve body is driven by the air pressure in the first space and the air pressure in the second space. A valve device according to claim 1,
The housing has a third seal portion that slidably holds the valve body,
The valve device, wherein the diameter of the second seal portion is larger than the diameter of the third seal portion. A valve device according to claim 1,
The cylinder chamber further has a third space farther from the valve body than the second seal portion,
The valve device in which the third space is open to the atmosphere. A valve device according to claim 3,
further comprising a proximity sensor that detects the open/closed position of the valve body,
The proximity sensor is a valve device arranged at a position closely facing an end side surface of the valve body extending through the third space. A valve device according to claim 1,
a directional control valve capable of switching between pressurizing and depressurizing the first space and switching between pressurizing and depressurizing the second space;
a high-speed exhaust valve capable of blocking the second space;
a valve device. A valve device according to claim 5,
A valve device in which the high-speed exhaust valve opens the second space while the directional control valve switches the second space from pressurization to depressurization. a mold having a cavity of predetermined shape;
a hot water supply unit for pumping molten metal into the cavity;
A die casting apparatus comprising a vacuum valve device for exhausting air in the cavity,
A die casting apparatus, wherein the vacuum valve device is the valve device according to any one of claims 1 to 6.

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