JPS6410312B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention extracts a large amount of gas from the mold cavity when molding a molded product using a molding machine equipped with a mold that can be clamped and opened, such as a die casting machine or an injection molding machine. The present invention relates to a method for installing a valve in a gas venting device for a mold.

Conventionally, die casting has been widely used as a molding method for manufacturing precision products in large quantities, but there are cases where die casting is not suitable for products where the integrity of the product is important, with no cavities inside.

This is because the cavity is filled with molten metal at high speed and high pressure, so the gas in the cavity may not escape sufficiently and may mix with the molten metal and remain in the product.

As a countermeasure, conventional methods have been considered, such as the non-porous die casting method in which the inside of the cavity is replaced with active gas, which is combined with the molten metal and fixed, and the method of reducing pressure. became complicated and not common.

The inventor of this invention investigated the relationship between the area of the air vent and the specific gravity value of the cast product using a die-cast model, and found that as the area of the air vent increases, the specific gravity value of the cast product also increases. However, the number of air vents is limited by the size of the product, and the thickness of the air vents cannot be greater than about 0.1 mm in order to prevent molten metal from passing through.

Therefore, we have developed a mold that can reliably and easily remove a large amount of gas, eliminate gas entrainment, and produce sound die-cast products without being restricted by the cast product or mold structure described above. developed a degassing device for

This device performs injection with the gas exhaust path leading from the mold cavity to the outside of the mold open by the action of a valve, and when the gas with a small mass in the cavity has almost finished being exhausted through the gas exhaust path. Then, by applying the inertial force of the large-mass injected molten part that has advanced from inside the cavity directly to the valve, the valve is reliably and quickly moved and closed, and the valve opens the gas discharge path. By directly blocking the flow of the molten material to be injected from the gas discharge path, the gas inside the mold can be reliably and easily vented during injection.

An example of a device adopting such a structure is shown in the first example.
- Shown in Figure 3.

In the figure, 3 is a fixed mold, and 4 is a movable mold.

On the side of the movable mold 4, an extrusion plate is provided that is moved forward and backward by a cylinder (not shown), etc.
This is provided with a plurality of push-out pins 6.
A cavity 7 is formed in the abutting surfaces of the fixed and movable molds 3 and 4, and below the cavity 7 is a molten material that is injected by an injection cylinder (not shown). A metal casting hole is formed.

On the other hand, on the fixed mold 3 side or the movable mold 4 side, a gas venting path 9 having a sufficient area is provided around the cavity 7 in a portion facing the other mold 3. A gas vent groove 10 is provided in communication with the upper end of the gas vent. This gas vent groove 10 may be formed in a shared state on the dividing surface of the two molds 3 and 4.

The valve head faces the gas vent groove 10 led from the cavities 7 of the molds 3 and 4 and is moved directly in the direction of action of the molten metal by the action of the molten metal advancing from the cavities 7. A disk type valve 14 is provided.

18 is a cylinder to which the fixed mold 3 is attached via a bracket 40, 19 is a piston rod of the cylinder 18, and at the lower end of the piston rod 19 is a spool 22 consisting of several parts that can be assembled and disassembled.
is fixed, and the spool 22 is slidably provided in a vertical half hole 23 provided in the fixed mold 3 and a vertical half hole provided in the movable mold 4 that matches this half hole 23. Ta. A chamber 24 is provided in the upper part of the spool 22,
A gas discharge hole 13 opening downward and a tapered valve seat 12 are provided at the bottom of the spool 22. A rod 25, which is a vertical valve stem, is provided at the center of the upper end of the valve 14, and a nut-shaped head 26a is attached to the tip of the rod 25, which penetrates into the chamber 24. Of course, the rod 25 is slidably provided on the spool 22. A compression spring 1 is provided between the upper surface of the head 26a of the valve 14 and the ceiling surface of the spool 22 in the chamber 24.
7 was installed. However, around the rod 25, the upper end surface of the valve head 14b of the valve 14 and the spool 2
A compression spring 1 is inserted between the bottom surface of the gas discharge hole 13 of No. 2 and
7 may be provided. Furthermore, a cylinder or the like may be provided in place of the compression spring 17. Gas exhaust hole 13
A gas exhaust passage 20 communicating with the outside of the mold was provided.

Following the gas vent groove 10, a valve chamber 11 that can be split in half is provided on both dividing surfaces of the two molds 3 and 4.
As can be seen from FIGS. 1 and 2, the valve chamber 11 includes an upper large diameter portion 11a into which the spool 22 is inserted, and a valve 14.
The valve head installation hole 11b is a small diameter portion at the lower end into which the valve head 14b of the valve head 14b is inserted.

The valve head 14b of the valve 14 has a tapered surface on the outer periphery of the back surface that seats on the valve seat 12, and when the valve head 14b is at the lower limit, the valve head 14b is in the valve chamber 11 where the valve head is installed. The outer peripheral surface of the valve head 14b is slidably fitted into the inner peripheral surface of the lower end of the valve chamber 11. 14a is a dish-shaped recess provided on the lower surface of the valve head 14b.

From the middle of the gas vent groove 10 just before the valve chamber 11,
A bypass 15 is provided between the side surface of the valve chamber 11 in front of the valve seat 12, which is the side surface of the movement path of the valve head 14b, and the side surface of the valve chamber 11, which is the side surface of the movement path of the valve head 14b.
By operating the valve 14, communication and interruption of the gas exhaust path between the bypass 15 and the outside of the mold can be directly regulated. The intersecting angle θ between the gas vent groove 10 and the inlet of the bypass 15 was set to be an acute angle or a right angle. Valve chamber 12
The opening 16 of the gas venting groove 10 facing is narrowed into a nozzle shape.

The spool 22 is slidably held by a guide 41 attached to a part of the bracket 40. Further, sensors 42 and 43 such as a limit switch and a non-contact switch are provided on the side surface of the bracket 40, and sensors 42 and 43 are provided on a part of the spool 22.
Attach the bar 44 that activates the sensor 4.
2 and 43 to confirm the lower limit and upper limit of the spool 22. From the head 26a of the valve 14, the bar 4
5 is provided by extending to the outside of the spool 22 through the notch 22a of the spool 22, and a sensor 46 such as a limit switch or a non-contact switch is attached to a part of the spool 22, and the bar 45 is connected to the sensor 46.
to ensure that the valve 14 is open and clear of the valve seat 12 before pouring the molten metal. And valve 1
After confirming that 4 is securely open, molten metal can be poured.

When operating the mold gas venting device configured as described above, the inventors installed a valve in the mold using the method shown below, and then installed a valve in the mold cavity during injection. I vented the gas.

That is, in the mold open state, the cylinder 18 is operated, the spool 22 is raised via the piston rod 19, and the valve 1 is opened by the force of the compression spring 17.
With 4 open, first insert piston rod 1.
9 is lowered to position the spool 22 and the valve 14 at the lower limit of the fixed mold 3, that is, at the large diameter portion 11a forming a part of the valve chamber 11 and the valve head installation hole 11b at the lower end. The mold is clamped, and the valve head 14b of the valve 14 is
was installed in the condition shown in Figures 1 and 2.

In this state, the bypass 15 is connected to the side of the valve chamber 11 and the gas discharge hole 13 which is a space inside the spool 22.
is in a continuous state.

If the molten metal is cast into the cavity 7 in this state, the gas in the cavity 7 will flow through the gas vent path 9 and the gas vent groove 1 while the molten metal is being filled into the cavity 7.
0, the bypass 15 and the gas exhaust hole 13 in the spool 22, and are exhausted from the gas exhaust path 20.
During this time, the valve head 14b of the valve 14 is in the valve head installation hole 11b, which is the lower end of the valve chamber 11, so the opening 16 of the gas vent groove 10 remains closed.
A large amount of gas escapes through the bypass.

Of course, at this time, the gas also acts on the lower surface of the valve head 14b through the opening 16, but since the mass of the gas is extremely small, the valve 14 does not rise.

When the filling of the molten metal into the cavity 7 is almost completed, the molten metal with a large mass flows into the gas vent groove 1.
0 and collides with the lower surface of the valve head 14b, and as a result, the valve 14 is pushed up against the compression spring 17, hits the valve seat 12, and closes. The molten metal pushes up the valve 14 and a part of it enters the bypass 15, but since the valve 14 is closed, the molten metal is blocked.

At this time, most of the gas that has passed through the bypass 15 has escaped, and the valve seat 12
Only a few remain nearby. This does not have any negative effect on the cast product.

When the casting work is completed, the cylinder 18 is operated to raise the piston rod 19 and the spool 2
2 and valve 14 are raised to a certain extent, the mold is opened. Subsequently, by operating the extrusion pin 6, the cast product is taken out from the movable mold 4, and at the same time, the metal solidified in the gas vent groove 10, the valve chamber 11, and the bypass 15 is taken out.

If such a degassing device is used, degassing can be reliably performed during casting, and the quality of the product can be significantly improved. This device utilizes the difference in specific gravity between gas and molten metal, for example, the difference in specific gravity between air and molten aluminum, which is 1:2000, and the difference in inertia based on this difference in specific gravity.

This degassing device has the above-mentioned excellent functions, but the spool 22 is raised for each casting operation, the valve 14 is also raised, and the valve chamber 1 is raised.
1 is separated from the valve head installation hole or valve chamber 11 and the mouth 16 of the gas vent groove 10. For this reason, if the valve head installation hole 11 at the bottom of the valve chamber 11
If molten metal scum or other foreign matter adheres to the bottom and inner peripheral surface of the valve head 14b, where the bottom surface and the lower outer peripheral surface of the valve head 14b come into contact, the valve 14 will not operate properly, resulting in inconvenience. occurs.

That is, as described above, if the mold is clamped after putting the spool 22 and the valve 14 into the fixed mold part 3,
If there is a foreign object on the fixed mold 3 side, which is the charging side of the valve 14, it can be detected because the valve 14 does not enter the specified position, but if there is a foreign object on the opposite side, the movable mold 4 side. In this case, there is no proper clearance between the valve head 14b and the mold for valve operation, and the valve 14
Since the metal is strongly pressed against the mold, there is a drawback that the valve 14 does not rise due to the inertia of the molten metal during injection. As a result, the molten metal flows into the spool 2 of the degassing device.
This has the disadvantage that it may flow into the inside of the tank, making continuous operation impossible.

The present invention has been made in order to eliminate the above-mentioned drawbacks.The present invention has been made in order to eliminate the above-mentioned drawbacks.The valve head of the gas venting device has foreign matter on the outer circumferential surface or in the valve head installation hole, which prevents the gas venting device from being set properly. The purpose of the present invention is to provide a method for installing a valve in a degassing device for a mold, which prevents the pouring of molten metal and failure of degassing by preventing the casting operation from starting if the degassing device is not installed. There is.

In order to achieve the above object, in the present invention, in a molding machine equipped with a mold that can be clamped and opened, a gas venting valve of a mold gas venting device is installed on a separation surface of the mold. At this time, the valve is installed at the end of the gas vent groove led from the cavity of the separation surface of both molds, consisting of a fixed mold and a movable mold, and is provided astride both molds. The valve is provided at the lower end of the valve chamber so that it can be taken in and out, and the mold is first clamped with the valve floating above the lower end of the valve chamber of one of the two molds. was carried out to align the valve chambers of both molds, and then the valve was successively advanced and inserted into the valve installation position at the lower end of the valve chamber.

In the present invention, mold clamping is performed with the valve device raised, that is, with the valve 14 floating above the lower end of the valve chamber 11, and with the valve chambers 11 aligned, the cylinder 18 is operated, Insert the lower end of the spool 22 into the valve chamber 11 to the lower limit position, and move the valve head 14b to the normal installation position of the valve head 14b.
That is, the valve head installation hole 11b immediately above the mouth portion 16
the valve 14 to the lower end of the valve chamber 11.

Therefore, if foreign matter is present on the wall surface of the valve head installation position 11b or around the opening 16 of the gas vent groove 10, and the valve 14 is prevented from descending, the bar 45 and the sensor 46 will be Not working, valve head 1
4b does not go all the way in, and the valve 14 is connected to the spool 22.
It is in an elevated position relative to the As a result, valve 14
The injection cylinder is not activated and no casting operation is being performed. Therefore, defects such as poor degassing do not occur.

As is clear from the above description, in the present invention, in a molding machine equipped with a mold that can be clamped and opened, a gas venting valve of a mold gas venting device is installed on the separation surface of the mold. At this time, the valve is installed at the end of the gas vent groove led from the cavity of the separation surface of both molds, consisting of a fixed mold and a movable mold, and is provided astride both molds. The valve is provided at the lower end of the valve chamber so that it can be taken in and out, and the mold is first clamped with the valve floating above the lower end of the valve chamber of one of the two molds. was carried out to align the valve chambers of both molds, and then the valve was moved forward and inserted to the valve installation position at the lower end of the valve chamber, so the mold gas venting device As long as the valve is not in a normal set state, that is, the valve head is securely set in the valve head installation hole and there is no foreign object or galling,
In addition, the injection cylinder can be kept inactive unless the valve is set in the open state, and as a result, problems such as poor degassing and molten metal spouting do not occur, and good quality is always maintained. You can get injection products.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of an apparatus for carrying out the present invention, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line -- in FIG. 3... Fixed mold, 4... Movable mold, 7... Cavity, 10... Gas vent groove, 11... Valve chamber, 11b... Valve head installation hole, 14... Valve, 14b... Valve head, 15... Bypass, 18... Cylinder , 20... gas exhaust path, 22
...Spool, 46...Sensor.

Claims (1)

[Claims] 1. In a molding machine equipped with a mold that can be opened and closed, when installing the gas venting valve of the mold gas venting device on the separating surface of the mold, both the fixed mold and the movable mold are The valve can be taken in and out of the lower end of the valve chamber, which is the installation position of the valve provided across both molds at the end of the gas vent groove led from the cavity of the separation surface of the mold. First, with the valve floating above the lower end of the valve chamber of one of the two molds, the molds are clamped to bring the valve chambers of both molds together; A method for installing a valve in a gas venting device for a mold, wherein the valve is subsequently moved forward and inserted to a valve installation position at a lower end of a valve chamber.