JPS6116223B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a degassing method for a mold that enables injection while removing a large amount of gas from the cavity of the mold during molding in an injection molding apparatus such as a die casting machine or an injection molding machine. It is related to the device.

Conventionally, die casting has been widely used as a molding method for manufacturing precision products in large quantities, but it has sometimes been unsuitable for products where the integrity of the product is important, with no cavities inside. The reason for this is that since the cavity is filled with molten metal at high speed and high pressure, the gas in the cavity is not sufficiently released and mixes with the molten metal and remains in the product, forming cavities in the product.

In order to eliminate this drawback, in order to be able to release a large amount of gas in a short time, there is a gas release groove led from the cavity on the parting surface of the mold, and the end of this gas release groove slides in the axial direction. and a detour passage from the middle of the gas vent groove to the side of the valve part, and during injection molding, the gas in the cavity is vented through the passage, and the molten material to be injected reaches the end of the gas vent groove. There is a degassing device that has a structure in which when the melt reaches the degassing point, the valve is pushed up by the action of this large-mass molten material, and the end of the detour passage is directly blocked by the valve body.

However, in this device, the operation of the valve body is not always reliable, especially when the melt to be injected reaches the valve body in a discontinuous state at the tip of the flow. There were times when I didn't. In other words, if the front end of the flow of melt is discontinuous, the valve will be closed by the first actuation of the melt, but when the next gas comes, the valve will close due to the action of the compression spring installed at the rear of the valve. open. Then, when the molten material comes again and you try to close the valve, the molten material in front of the valve position that came earlier is about to solidify, so the valve is not closed enough and enters the bypass passage. There was a risk that the molten material would enter the valve.

Moreover, when the product was removed from the mold after molding and prepared for the next molding, the valve body sometimes did not return to its normal position.

The present invention eliminates the above-mentioned drawbacks and provides a gas venting device for an injection mold, which is equipped with a valve body that quickly and reliably closes the exhaust port when the first melt to be injected reaches the valve body. To provide a device that reliably advances a valve body when opening a mold after molding to prepare for the next casting.

That is, the present invention allows gas to be released by the action of the molten material to be injected that advances from the cavity into the separation surface of the mold, which has concave and convex portions facing each other, in a gas vent groove led from the cavity of the mold. A valve that is moved directly in a direction different from the axial direction of the vent groove is provided, and a passage for gas discharge is provided that leads from the gas vent groove to the side of the valve movement path. The valve is locked in the open position with respect to an elastic body that applies a force in the direction of closing the valve and a support that slidably supports the valve. In an injection molding apparatus, the locking mechanism is disposed between the support body and the valve, and the locking mechanism is disengaged when the valve is closed, and the valve opening device is configured to open the closed valve. It was used as a degassing device for molds.

Then, injection is performed with the gas exhaust passage leading to the mold from the passage detoured from the middle of the gas vent groove to the side of the valve part opened by the action of the valve, and first, the gas having a small mass that has advanced from the cavity is released. , when acting on the end face of the gas venting groove side of the valve, the valve is at the end on the gas venting side, and the gas is discharged through the detour passage and the valve portion, and when the gas has almost finished being discharged; Then, when the first inertial force of the large-mass injected molten material that has proceeded from the cavity acts directly on the end face of the gas vent groove side of the valve, the valve moves backward and the gas discharge channel is opened by the valve. Directly shut off the molten material to be injected to prevent it from being discharged to the outside, ensure that gas inside the mold can be easily vented during injection, and after opening the mold after molding.
A valve opening device such as an extrusion rod attached to the product extrusion device is used to open the gas discharge passage and prepare for the next molding.

Hereinafter, details of the present invention will be explained along with embodiments shown in the drawings.

Figures 1 to 3 are for explaining one embodiment of the present invention, and in the figures, 1 is a fixed plate, 2 is a movable plate, 3 is a fixed mold, 4 is a movable mold, and 5 is an extrusion plate. , 6 indicates an extrusion pin, 7 indicates a cavity of the movable mold 4, and 8 indicates an injection sleeve. A plunger 9 is slidably fitted into the injection sleeve 8. A molten metal supply port 8a is formed near the outer end of the injection sleeve 8.

In the fixed mold 3, a shallow gas venting groove 10 having a sufficient area is formed in a portion around the cavity 7 facing the movable mold 4. The gas venting groove 10 is one gas venting groove 1 as shown in FIG.
1, and this gas vent groove 11 is provided on the dividing surface of the fixed mold 3.

As shown in FIGS. 1 to 3, this gas vent groove 11 is orthogonal to a valve chamber 12 that is shared by the fixed mold 3 and the movable mold 4, which have concave and convex portions facing each other. are communicating.

This valve chamber 12 is clearly shown in FIG.
It has an axis that is perpendicular to the axis of 1 or intersects in another different direction, and its bottom surface is a conical surface formed in the shape of a mortar. A valve 13 is slidably fitted into the valve chamber 12. The valve stem 13a of the valve 13 is
A guide block 14 is formed on the movable mold 4 side, extends toward the through hole 4a that is continuous with the valve chamber 12 via the valve seat 13b, and is fixed to the movable mold 4 in the through hole 4a section. A cylindrical body 16 is fixed to the movable mold 4 by bolts 17 so as to surround the valve stem 13a at the portion passing through the guide block 14. A tension spring 18 that applies a force in the direction of closing the valve 13 is elastically mounted between the back surface of the tip of the cylindrical body 16 and the tip of the valve stem 13a.
A stopper 15a is provided at the rear end of the guide block 14.
The valve 13 can be held in the open position by a locking mechanism 15 such as the above-described locking mechanism 15 against the elastic body 18 such as the tension spring.

On the other hand, in the vicinity of the valve chamber 12, the gas vent groove 11 has detour passages 19, 19 branching left and right as shown in FIG.
As shown in FIGS. 2 and 3, 9 is a valve chamber 1 along a dividing surface of a mold having concave and convex portions facing each other.
It detours to the side of the movement path of the second valve 13 and opens into the valve chamber 12. The opening of this bypass passage 19 to the valve chamber 12 is located on the valve stem 13a side of the valve 13 when the valve 13 is in its forward, non-operating state, and communicates with the through hole 4a. And valve 1
3 moves backward to a position where it contacts the valve stem 13b, this opening is closed by the outer peripheral surface of the valve 13.

The through hole 4a is a discharge passage 4b formed in the movable mold 4.
is connected to.

A return rod 23 projects outward from the cylinder 16 through the notch 16a of the cylinder 16 at the end of the valve stem 13a, and the return rod 23 is pressed by a return pin 22 attached to the push-out plate 5. However, the structure is such that the valve 13, which is closed, can be set to an open state by moving the valve forward.

Note that the locking mechanism 15 such as the stopper 15a is
As shown in FIG. 4 and FIG. 4, the notch step 13c provided on the outer peripheral surface of the valve stem 13a is pressed against the ball 15b by a compression spring provided in the guide block 14. In some cases, a compression spring and a ball 15b are built into the valve stem 13a. In addition, as shown in FIGS. 8 and 9, the valve stem 13a
A pressing piece 15 with a square cross section and a tapered surface formed on the
When the valve stem 13a is pressed and clamped from the left and right sides of the valve stem 13a, and when the valve stem 13a is pressed and clamped by a leaf spring 15d as shown in FIG. In some cases, a leaf spring is installed in the

In short, a locking mechanism 15 is provided that maintains the valve 13 in an open state while constantly applying a force for retracting the valve 13 using an elastic body 18. Any device that releases the clamping lock of the valve body upon impact is sufficient. In addition, the elastic body 18
The present invention is not limited to the case where a tension spring is provided between the rear end of the valve stem and the back surface of the top of the cylinder body 16, and a compression spring may be provided between the return rod 23 and the guide block 14.

Next, the operation of this embodiment configured as above will be explained.

First, mold clamping is performed with the valve 13 open, and the third
As shown, the valve 13 is set within the valve chamber 12 in the forward position. Then, when the molten metal is injected into the injection sleeve 8 and the injection plunger 9 moves forward,
The molten metal in the injection sleeve 8 flows into the cavity 7 at high velocity. Accordingly, the gas having a small mass in the cavity 7 is guided toward the valve chamber 12 via the gas vent grooves 10 and 11. However, valve chamber 12
is sealed by a valve 13, and since gas with a small mass cannot push the valve 13, the gas detours to the outside of the valve 13 through the bypass passage 19, and passes through the through hole 4a and the gas discharge passage 4b. Exhausted to the outside air. After that, the molten metal to be injected enters through the gas vent grooves 10 and 11.
This molten metal has a large mass and high velocity, so
First, go straight ahead without detouring towards detour path 19.
Head into the valve chamber 12.

Since the bottom surface of the valve chamber 12 is formed into a conical shape as described above, the molten metal that has advanced straight collides with this slope, changes direction by approximately 90 degrees, and collides with the end surface of the valve 13. At this time, the first molten metal
3, a force acts on the valve 13 to the left in FIG. 3, the locking mechanism 15 consisting of a ball etc. is released, the valve 13 is pushed to the left in the figure, and Since the valve is pulled by the elastic body 18, the valve is moved backward at high speed by the initial impact of the molten metal, and the valve seat 13b formed at the base end side of the through hole 4a is moved.
sit down. Thereafter, even if the molten metal stops momentarily and gas hits the valve, the valve 13 will not open because it is pulled by the elastic body 18. As a result, the opening of the bypass passage 19 to the valve chamber 12 is blocked by the circumferential surface of the valve 13, and the opening of the bypass passage 19 and the through hole 4 are blocked by the circumferential surface of the valve 13.
a, communication with the gas exhaust path 4b is cut off.
As a result, the gas discharge passage is blocked by the action of the molten metal itself, and the discharge of the molten metal to the outside is completely blocked. Therefore, the molten metal fills the valve chamber 12 and the detour passage 19, but does not enter the through hole 4a.

In the above embodiment, after the injection molding is finished, the molten metal is cooled and solidified, and the mold is opened, the waste metal solidified in the degassing grooves 10, 11 and the bypass passage 19 of the valve chamber 12 is removed from the injection molding. It is peeled off from the fixed mold 3 side while being attached to the movable mold 4 as one with the product. Thereafter, the extrusion plate 5 advances and the extrusion pin 6 releases the waste metal from the movable mold 4 together with the molded product in the cavity 7.

When this product extrusion is performed, the return pin 22
moves forward at the same time, and the return lever 2 moves forward due to the action of the return pin 22.
3 is pressed, and as a result, the valve 13 moves forward against the elastic force of the elastic body 18 and becomes open, and the open state is maintained by the locking mechanism 15 to wait for the next operation. . At this time, since the valve 13 is held open by a locking mechanism such as a ball, the valve 13 remains open even if the push-out plate 5 and the return pin 22 retreat.

Since this embodiment is configured as described above,
During injection molding, gas flows from the bypass passage 19 to the groove 1.
The molten metal having a large mass is discharged to the outside through the gas discharge passage 4b through the gas discharge passage 4b, and the molten metal having a large mass that subsequently enters is reflected by the slope of the valve chamber 12, and is reflected in the axial direction of the gas vent groove 11. changes direction by about 90 degrees and crashes into the valve 13, causing the valve to retreat to the left by disengaging the locking mechanism 15, and the groove 11 and detour 19
Since the opening end of the detour passage 19 is blocked by the circumferential surface of the valve 13 by shifting the opening end of the detour passage 19 from the opening end of the detour passage 19, the passage with the outside is blocked and the valve is closed by the action of the molten metal itself. Therefore, molten metal is not discharged outside the mold.

As is clear from the above description, according to the present invention, in the gas vent groove led from the mold cavity,
A valve is provided in a direction different from the axial direction of the gas vent groove, and a detour path is provided from the gas vent groove to a side surface of the valve, and the valve is communicated with the outside by the molten material to be injected that has proceeded from the cavity. Since the passage can be blocked, the gas inside the mold cavity can be reliably discharged, and the discharge of the molten material to be injected to the outside can be completely prevented.
That is, a large amount of gas can be efficiently extracted during injection molding, no cavities are formed in the product, and when the molten material to be injected reaches the valve 13 position, the first molten material can quickly and reliably close the valve 13. can be closed.

After molding, a return pin 2 attached to the extrusion plate 5 that pushes out the molded product when the mold is opened and the molded product is taken out.
2 to advance the return rod 23 of the valve body, not only can the solidified metal in the valve chamber 12 be reliably discharged, but also the valve 13 can be automatically and reliably set to the open state. In the above embodiment, the valve stem 13a is provided on the guide block 14 attached to the movable mold 4, but as shown in FIG.
In some cases, a is provided.

In this embodiment, a cylindrical valve stem 13a with a hollow interior is used, and a tip 13d that becomes a valve is attached to a movable mold 4.
After the detour path 19 branches off as shown in FIGS. 4 to 6, the gas vent groove 11
is formed so as to bite into the movable mold 4, and the valve chamber 12
lead to. The end of the detour passage 19 is connected to the valve stem 13a.
The gas exhaust path 3 is provided in the fixed mold 3 through a notch 13e provided around the valve stem 13a.
Connects to b. Further, an enlarged portion is formed at the rear end of the valve stem 13a to serve as a return rod 23, and an actuator 25 such as a solenoid type cylinder is provided at the rear of the cylinder 16. Return pin 2 attached to the actuator 25
2 penetrates the cylindrical body 16 and presses the return rod 23 to advance the valve stem 13a.

Note that the actuator 25 is not limited to electromagnetic operation, but may be hydraulically operated, and the actuator 25 and the operation cylinder of the extrusion plate 5 provided in the movable mold 4 are electrically or hydraulically coupled. In conjunction with the operation of the push-out plate 5, the return pin 22 provided on the actuator 25 also moves forward.

By using the method and device as described above, many effects can be expected as described below.

(1) When most of the gas with a small mass has escaped, the inertia of the injected melt with a large mass following the gas directly pushes the valve, thereby blocking the gas discharge path. Therefore, the valve operates quickly and reliably, and gas removal and prevention of discharge of the molten material to be injected from the valve portion can be performed reliably and easily. In particular, since the molten material to be injected collides with the slope and its reflection acts on the valve, the valve operates quickly and reliably. In addition, degassing is performed automatically in perfect synchronization with each casting operation, and the timing will not be out of order.
Gas venting operation becomes stable.

(2) A locking mechanism 15 is provided that maintains the open state while constantly applying force to the valve body 13 in the direction in which the valve retreats using the elastic body 18, and the locking mechanism is activated by the first impact of the melt to be injected. The elastic body 18 is used to close the valve and maintain the closed state of the valve, so even if the molten material to be injected reaches the valve 13 discontinuously, the valve is reliably closed by the first molten material to be injected.

(3) Since gas can be sufficiently vented during injection, residual gas in the injection product is greatly reduced, and the hot water performance, pressure resistance, and airtightness of the injection product are significantly improved.

(4) When moving the valve body forward using a return pin attached to the molded product extrusion plate or a return pin that interlocks with the extrusion plate, it is not only possible to set the valve body to the open state at the same time as the product is extruded, but also to eject waste metal reliably and safely. be able to. Therefore, the occurrence of burrs at the air vent portion on the outer periphery of the cavity is reduced, so there is no need to remove burrs, and the mold is not damaged. The result is easier automation and longer mold life.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view showing one embodiment of the present invention;
FIG. 2 is a sectional view taken along the line - in FIG. 1, FIG. 3 is a partially enlarged sectional view of FIG. 1, FIG. 4 is a diagram showing another embodiment of the present invention, FIGS. 5 and 6 are respectively a diagram showing a V-V line cross section and a - line cross section in FIG. 4,
FIGS. 7 to 11 are diagrams showing various locking mechanisms. 1... Fixed plate, 2... Movable plate, 3... Fixed mold, 4... Movable mold, 5... Extrusion plate, 6... Extrusion pin, 7... Cavity, 8... Injection sleeve,
9... Injection plunger, 10, 11... Gas vent groove, 12... Valve chamber, 13... Valve, 13a... Valve stem, 13b... Valve seat, 14... Guide block,
15... Locking mechanism, 16... Cylindrical body, 18... Spring, 19... Detour passage, 20... Passage, 22
...Return pin, 23...Return rod.

Claims (1)

[Claims] 1 The axis of the gas vent groove is guided from the cavity of the mold, and the axis of the gas vent groove is caused by the action of the molten material to be injected advancing from the cavity on the separation surface of the mold that has uneven parts facing each other. A valve that can be moved directly in a direction different from the above direction is provided, and a gas exhaust passage leading from the gas vent groove to the side of the moving part of the valve is provided, and the operation of the valve opens the gas exhaust passage between this passage and the outside of the mold. The valve is locked in the open position with respect to an elastic body that applies a force in the direction of closing the valve and a support body that slidably supports the valve, so that the valve can be opened or shut off. Gas venting for a mold in an injection molding apparatus, which is provided with a locking mechanism that is unlatched and released between the support body and the valve, and a valve opening device that opens the closed valve. Device.