JPH08117957A - Degassing device for mold - Google Patents

Abstract

(57) [Summary] [Purpose] The compressed air valve does not deform and the stable sealing can be maintained. [Structure] A valve guide in which a valve is slidably provided inside a degassing portion of a die, and a spool engaged with the valve guide are provided by a cylinder so as to be movable in the sliding direction of the die and the die is The valve rod of the valve is provided as a piston so as to be slidable in the spool and has a surface contact between the valve portion and the valve seat portion between the piston and the valve guide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold degassing device used in a molding machine such as a die casting machine, and more particularly to improving the durability of a sealing surface when a valve is opened and closed.

[0002]

2. Description of the Related Art Conventionally, die casting has been widely used as a method for producing a large amount of precision products, but it may not be suitable for products in which the integrity without nests inside the products is important.

The reason for this is that the molten metal is filled into the cavity at high speed and high pressure, so that the gas in the cavity may not fully escape and may mix with the molten metal and remain as a nest in the product. is there.

In order to eliminate such inconvenience,
The present inventors have developed a mold degassing device capable of reliably and easily releasing a large amount of gas without being restricted by a cast product or a mold, and obtaining a sound die-cast product by eliminating gas entrainment. There is.

In these devices, injection is performed with the discharge passage leading from the mold cavity to the outside of the mold kept open by the action of a valve, and the gas having a small mass inside the cavity is discharged through the gas discharge passage. At this point, the inertial force of the injected melt having a large mass that has advanced from the inside of the cavity directly acts on the valve to quickly move and tighten the valve to directly shut off the gas discharge path. This is intended to prevent the outflow of the melt to be injected from the passage so that the gas in the mold can be easily released during injection.

[0006]

However, in these devices, as shown in FIG. 6, the primary air blowing through hole 16 and the tertiary air blowing hole 16 of the piston 14 from the head block 10 through the valve guide 12 are used. Compressed air is blown into the through hole 19 to open and close the valve 20. Further, the compressed air is constantly blown into the secondary air blowing through hole 18, and when the valve 20 is opened, that is, when the piston 14 is in close contact with the O-ring 22, the secondary air blowing through hole 18 is opened. Compressed air blown into the hole 18 causes the piston expanded portion 14
It acts on a and maintains the valve 20 in the open state.

When the molten metal is injected, for example, the speed is 40 m / sec per second.
When the valve 20 is closed due to the inertial force of the first molten metal when the flakes are intermittently advancing at an extremely high speed like the above, the compressed air blown into the secondary air blowing through hole 18 is , Acts on both the upper portion 15a and the lower portion 15b of the piston expanded portion 14a, but the valve 20 maintains the closed state because the area of the lower portion 15b is larger than the area of the upper portion 15a of the piston expanded portion 14a.

As described above, the opening / closing operation of the valve 20 is performed. However, the temperature around the O-ring 22 has risen up to about 100 ° C., so that the O-ring 22 is largely deformed and crushed in a constant manner. However, there was a problem that the sealing performance of the valve part gradually deteriorates due to long-term continuous operation.

The present invention has been made in view of the above problems, and it is possible to maintain a stable sealing property without changing the sealing property of a valve portion that applies downward pressing force at the time of valve opening even during long-term continuous operation. It is intended.

[0010]

In order to achieve the above object, according to the present invention, a valve guide having a valve slidably provided therein and a spool engaged with the valve guide are provided in a gas releasing portion of a mold. Is provided so as to be movable in the sliding direction of the valve by a cylinder so that it can be installed in a mold, and the rear end of the valve rod of the valve is used as a piston so as to be slidable in the spool and the piston and the valve guide. The valve portion and the valve seat portion in between are configured to have surface contact.

[0011]

When the valve and the spool are set in the degassing part of the mold, the cylinder is operated with the valve opened to move the valve and the spool forward to set them. At that time, the solenoid switching valve 8
The B side of 2 is electromagnetically actuated, and the compressed gas is made to act on the piston head part side of the rear end part of the valve rod part, and the force in the valve opening direction is made to act.

After the valve is set in the mold with the valve open, the vacuum pump is driven during the injection to discharge the gas in the cavity as much as possible. Further, due to the advance of the molten metal, the residual gas in the cavity is discharged to the outside of the mold through the open valve portion.

After the molten metal fills the cavity by the injection operation, if the molten metal moves forward through the degassing groove and collides with the lower surface of the valve head of the valve, the inertial force of the molten metal will flow from the secondary air blowing through hole. The injected compressed gas acts on the valve portion in a state where it is larger than the force that always presses it downward, so the valve closes and molten metal does not enter the valve device.

When the injection operation is completed and the molten metal in the cavity and the degassing groove is cooled and solidified, the cylinder is operated to extract the tip of the valve device from the mold and open the mold, and then the injection product is removed. Even when performing the above-described continuous forming operation, the valve seal between the lower part of the piston and the valve guide and the valve seat are made of surface-contact metal seals so that the valve can be used repeatedly for a long period of continuous operation. Since it does not wear even when opening and closing, the sealing pressure can be kept constant and the valve can be opened and closed reliably.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a vertical sectional view of a mold degassing apparatus according to an embodiment of the present invention, FIG. 2 is a partially cut sectional view taken along the lines AA of FIG. 1, and FIG. 3 is a contact between a piston and a valve guide. FIG. 4 is a partially enlarged sectional view showing a state, FIG. 4 is an explanatory view showing a closed state of the valve,
FIG. 5 is an explanatory view showing an open state of the valve.

In the figure, reference numeral 30 designates a fixed mold, 32 designates a movable mold, and 30a and 32a designate half-divided seats which are respectively fitted to the dividing surfaces of the fixed mold and the movable mold. Here, the seats 30a and 32a are fixed molds 3, respectively.
0, a part of the movable mold 32.

A degassing device 34 is provided on the dividing surface of the fixed mold 30 and the movable mold 32 and its extended position.

On the other hand, the gas vent groove 4 is formed from the gas vent passage 38 formed on the dividing surface of the mold from the periphery of the cavity 36.
An exhaust passage is formed through 0 to the lower portion of the gas venting device 34.

In the gas venting device 34, the valve 20 is provided so as to be substantially vertical to the lower surface of the valve head 20a with respect to the gas venting groove 40, and the valve head 20a is provided laterally from the middle of the gas venting groove 40. A gas discharge passage 42 is provided, which bypasses in the direction and reaches the upper side of the valve head 20a. Reference numeral 42a is a hot water pool.

The valve 20 slides in the spool 44, which is a valve support member, in the axial direction with respect to the spool 44, and when the valve 20 moves upward in FIG.
The valve head 20a comes into contact with the valve seat 46 provided at the lower end of the spool 44, and the passage 42 is closed from the communication state with the valve chamber 48 in the spool 44.

A valve chamber 48 formed around the valve rod 20b is continuous above the valve head 20a, but a discharge port 50 is formed in the valve chamber 48 and a vacuum pump 5 is provided through a pipe 51.
Connected to 3.

The piston 14 is fixed to the upper end of the valve rod 20b in the middle of the spool 44, and the piston 14 is slidably fitted in the head block 10 formed at the upper end of the spool 44. .

The primary air blowing through hole 16 communicating with the head portion 14b of the piston 14 and the lower portion 14c of the piston 14
The third air blowing through-holes 19 which are expanded in diameter and engage with the valve seat portion 52 in an inclined state provided on the upper end of the valve guide 12 to communicate with the sealable valve portion 54 are respectively provided in the spool 4
4 is provided.

Here, the material of the piston 14 is preferably SCM-435 (3 types of chrome molybdenum alloy), and the material of the valve guide 12 is preferably SKD-61 (61 type of alloy tool steel).

A ring groove 56 is formed in the valve rod 20b in the state of being orthogonal to the valve opening / closing check line 21. As shown in FIG. 3, when the ring groove 56 is located on the same axis as the valve opening / closing check line 21, it is turned on and the valve 20 is found to be in the open state. Is configured so that the compressed air from the valve opening / closing check line 21 is shut off and that the valve 20 is closed.

On both sides of the upper end portion of the spool 44, projecting portions 60 are integrally projectingly engaged with the spool 44 to form a T-shape having projecting portions 60a and 60b.

The projecting portion 60 is fixed to the lower end of a piston rod 64a of a cylinder 64 fixed to a bracket 62 fixed to the fixed mold 30 side.

Guide rods 66a, 66 fixed to the bracket 62 and inserted through the protruding portions 60a, 60b.
b is slidably fitted to the gas venting device 34 via a shoe 67.

From the compressed air source 70, each air blowing through hole 1
Pipes are connected to 6, 18, and 19.

The compressed air source 70 and the electromagnetic switching valve 82 are connected by a pipe 80. Further, the primary air blowing through hole 16 is a pipe 84, and the tertiary air blowing through hole 19 is a pipe 8.
6 are connected respectively.

Pipes 88 branching from the pipe 80 are connected to the switching valves 90 and 92, respectively, and between the switching valve 90 and the secondary air blowing through hole 18 is a pipe 94 and the switching valve 92 and the valve. The open / close check line 21 is connected by a pipe 96.

Next, the operation of the present embodiment constructed as above will be described.

First, the switching valve 90 is normally turned on, and compressed air from the compressed air source 70 is supplied to the pipe 88, the switching valve 90, and the pipe 9.
Then, the air is fed to the secondary air blowing through hole 18 through the No. 4.

On the other hand, when the B side of the electromagnetic switching valve 82 is excited, the electromagnetic valve shifts to the right side and the compressed air from the compressed air source 70 to the primary air blowing through hole 16 is pipe 80 and the electromagnetic switching valve 8.
2. It is fed to the primary air blowing through hole 16 through the pipe 84 and acts on the piston head portion 14b.

Therefore, since a downward force acts on the piston 14 and the valve 20 (FIG. 5), the valve 20 will not be closed by a shock when the spool 44 or the like is lowered by the action of the cylinder 64.

In this state, the cylinder 64 is operated to
The spool 44 is lowered to a predetermined position and the mold is clamped. At this time, since the valve 20 is open, a passage is formed from the cavity 36 to the outside of the spool 44 through the gas vent passage 38, the gas vent groove 40, the passage 42, and the valve chamber 48.

In this state, the B side of the electromagnetic switching valve 82 is demagnetized, the vacuum pump 53 is driven, and the injection plunger (not shown) is actuated before starting or during operation.
The injection molding operation is performed while vacuum suctioning the gas in the cavity 36 and the valve chamber 48. In this way, the gas in the cavity 36 is forcibly discharged.

At the time of injection, the molten metal filling the cavity 36 proceeds through the gas vent passage 38 and the gas vent groove 40, but the residual gas in the cavity 36 passes through the passage 42 and the valve chamber 48 and is discharged. Head in 50 direction. Since the gas has a small mass, the valve 20 does not close due to the action of the gas.

On the other hand, following the gas, molten metal is introduced into the valve head 30.
It collides with the lower surface of a. At this time, the impact applied to the valve 20 is much larger than the impact of the gas on the valve 20 because the mass of the molten metal is much larger than that of the gas and the inertia is large.

As a result, in the valve 20, the piston 14 is pulled upward against the downward pressure acting on the valve portion 54 from the secondary air blowing through hole 18, and the upper surface of the valve head 20a is opened. The seat 46 is seated, the passage 42 and the valve chamber 48 are closed, and the outflow of molten metal is stopped at the valve 20 (FIG. 4).

At this time, the molten metal mixes with the gas in the gas venting passage 38 and the gas venting groove 40 to form a droplet, and even if the molten metal strikes the valve disc discontinuously, the valve 20 is caused by the first collision of the molten metal. Even if the gas is blown up and then the pressing force of the molten metal upwards disappears, the compressed air sent from the secondary air blowing through hole 18 remains in the valve portion 54.
And the inertia of the upward movement is applied, the exhaust passage is reliably closed by the valve 20.

Here, the electromagnetic valve on the A side of the electromagnetic switching valve 82 is energized and provided in the tertiary air blowing through hole 19 via the pipe 86 because the molding apparatus is operated for several days or hours. When the mold is not in operation and the temperature of the mold has not reached the specified temperature and the molten metal cannot be expected to have the inertial force necessary to close the valve, the operation should be restarted or the filling of the molten metal should be started. This is because the valve 20 is forcibly closed during the operation.

In this way, when injection is performed and the casting operation is completed by pressurizing and cooling for a predetermined time with the valve 20 of the degassing device 34 closed, the cylinder 64 is operated and the spool 44 is raised. Let

Along with this ascending operation, the cavity 36, the degassing passage 38, the degassing groove 40, and the passage 42.
The solidified and solidified metal leaves the rising valve 20. Then, after the mold is opened, the molded product is taken out of the movable mold 32 by a product extruding device (not shown).

As described above, in this embodiment, after the molten metal is filled in the cavity 36, the valve 20 is repeatedly opened and closed by a long-term continuous operation of cooling and taking out as a product. Part 52 and piston 14
Since the state in which the side valve portions 54 have a sealing surface portion having a large contact area is provided, it can withstand repeated opening and closing use for a long period of time.

[0047]

As is apparent from the above description, according to the present invention, a valve guide having a valve slidably provided therein and a spool engaged with the valve guide are provided in the gas venting portion of the mold. A cylinder is provided so that it can move in the sliding direction of the valve so that it can be installed in a mold, and the rear end of the valve rod of the valve is used as a piston so that it can slide in the spool and the space between the piston and the valve guide. Since the valve section and the valve seat section are configured to be in surface contact with each other, the metal seal section does not deform even if the valve is repeatedly opened and closed under a temperature rise condition, so that the seal can be reliably performed when the valve is closed. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a mold degassing device according to an embodiment of the present invention.

FIG. 2 is a partially cut cross-sectional view seen from AA of FIG.

FIG. 3 is a partially enlarged sectional view showing a contact state between a piston and a valve guide.

FIG. 4 is an explanatory view showing a closed state of a valve.

FIG. 5 is an explanatory diagram showing an open state of a valve.

FIG. 6 is a partially enlarged sectional view showing a contact state between a conventional piston and a valve guide.

FIG. 7 is an explanatory view showing a closed state of a conventional valve.

FIG. 8 is an explanatory view showing an open state of a conventional valve.

[Explanation of symbols]

 10 head block 12 valve guide 14 piston 14b head portion 14c lower part 16 primary air blowing through hole 18 secondary air blowing through hole 19 third air blowing through hole 20 valve 20a valve head 20b valve rod 21 Valve open / close check line 22 O-ring 30 Fixed mold 32 Movable mold 34 Gas venting device 36 Cavity 38 Gas venting channel 40 Gas venting groove 42 Passage 44 Spool 46 Valve seat 38 Valve chamber 50 Discharge port 51, 80, 84, 86, 88, 94, 96 Piping 52 Valve seat 53 Vacuum pump 54 Valve 56 Ring groove 64 Cylinder 70 Compressed air source 82 Electromagnetic switching valve 90, 92 Switching valve

Claims (1)

[Claims] 1. A degassing portion of a mold, wherein a valve guide having a valve slidably provided therein and a spool engaged with the valve guide are provided by a cylinder so as to be movable in a sliding direction of the valve. It is installed in a mold so that the rear end of the valve rod of the valve is a piston and is slidable inside the spool, and the valve and valve seat between the piston and valve guide are in surface contact with each other. A degassing device for molds, which is characterized in that