JPS6116224B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold degassing device that extracts only a large amount of gas from a mold cavity in a molding machine such as a die casting machine or an injection molding machine during injection molding.

Conventionally, when a cavity is filled with molten metal at high speed and high pressure in a die-casting machine or the like, the gas in the cavity does not escape sufficiently and remains in the product, resulting in the formation of cavities in the product. In order to eliminate this drawback, the inventor of the present invention created a gas vent groove led from the cavity in the separation surface of the mold so that a large amount of gas can be vented in a short time. A valve that slides in the direction and a passage serving as a bypass leading from the gas vent groove to the side surface of the valve part are provided. During injection molding, the gas in the cavity is vented through the bypass, and the injected molten material flows through the gas vent groove. When the end of the bypass is reached, the valve is pushed up by the action of this large-mass molten material, and the valve body directly closes the end of the bypass. but,
When the molten material to be injected reaches the valve body in a discontinuous state at the leading end of its flow, the valve body may not operate satisfactorily. In other words, if the leading edge of the melt flow is discontinuous, the valve will be closed by the first actuation of the melt, but when the next gas arrives, the valve will close due to the compression spring installed at the rear of the valve. Opens by action. Then, when the molten material comes and tries to close the valve, the molten material in front of the valve position that came first is about to solidify, so the molten material does not act directly on the valve, and Acts on melts. At this time, friction is acting between the molten material that is about to solidify and the surrounding mold part, so the force acting on the valve becomes weaker, and the valve is not tightened sufficiently, resulting in a bypass. There was a risk that the incoming molten material would enter the valve.

The present invention eliminates such drawbacks and provides a gas venting device for an injection mold that 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. It is something to do.

In the gas venting device for a mold in a molding machine of the present invention, a gas venting groove led from the cavity is provided in the separation surface of the mold, a valve is slidable at the end of the gas venting groove, and the valve is slidable. A support body is fixedly attached to a part of the mold, and a gas exhaust passage leading from the gas vent groove to the side surface of the valve part is provided, and a force is applied in the direction of closing the valve. and a locking mechanism that locks the valve in the open position with respect to the support that slidably supports the valve and releases the lock as the valve closes. A valve opening device was attached to the support, which was provided between the valve and the valve, and which pushed the closed valve into an open state.

Next, the present invention will be explained in detail with reference to an embodiment shown in the drawings.

The mold degassing device according to the present invention includes, for example,
It is provided at the dividing plane between the fixed mold 1 and the movable mold 2 and at an extended position thereof.

That is, when the fixed mold 1 and the movable mold 2 are combined, for example, a gas vent path 4 and a gas vent are formed on the divided surface of the movable mold 2 from the appropriate periphery of the cavity 3. An exhaust passage leading to the gas venting device is formed through the groove 5.

As the gas venting device for the mold, the valve 6 is provided so that the gas venting groove 5 and the lower surface of the valve head 6a of the valve 6 are substantially perpendicular, and the valve head 6a is opened from the middle of the gas venting groove 5. Seven passages are provided, each consisting of a bypass that detours to the side of the valve head 6a and reaches the upper side of the valve head 6a. The valve 6 slides in the axial direction with respect to the support 8 within the support 8 fixed to the fixed mold 1. For example, when the valve 6 moves upward in FIG. The valve head 6a was brought into contact with a valve seat 9 provided at the lower end of the support 8, and communication between the gas vent groove 5 and the passage 7 to the valve chamber 10 in the support 8 was closed. Then, it is directly moved and closed by the action of the molten material to be injected advancing from the cavity 3.

Above the valve 6, there is a valve chamber 10 space formed around the valve stem 6b of the valve 6, and a discharge port 11 from the valve chamber 10 to the outside of the support body 8 is provided. The valve stem 6b is a support 8
In contrast, it is slidably supported by the valve stem guide portion 12. And between the valve 6 and the support body 8,
An elastic body 13 is provided that applies a force in the direction of sliding the valve 6 upward to close it, and the valve 6 stops at a downward position, that is, an open position, with respect to the support body 8, and by the closing operation of the valve 6, Locking mechanism 1 whose lock is released
4 will be provided. That is, a tension spring is provided as an elastic body 13 between a block 15 attached to the rear end of the valve stem 6b and the top of the support 8, and the tension is applied to constantly pull the valve 6 upward with respect to the support 8. Make sure to add it with a spring force. However, when the valve 6 is open, the locking mechanism 14 cannot be moved only by the action of the elastic body 13.
The elastic body 13 is made of an elastic body whose tensile force is appropriately adjusted so as not to come off. Further, a tapered recess 16 is provided on the outer peripheral surface of the valve stem 6b, and the recess 16 is formed in the hole 17 provided toward the outer peripheral surface of the valve rod 6b in the valve rod guide portion 12 of the support body 8. A ball 19, which is a pressing piece, is provided so as to be retractable by the action of a compression spring 18. 20 is a bolt that can adjust the pressing force of the ball 19;
It's a stop nut. The recessed portion 16 provided on the outer circumferential surface of the valve stem 6b may be a vertical groove as shown in the figure, or may be a small diameter cylindrical portion in which the entire circumferential surface of this portion is smaller than the outer diameter of the valve stem 6b. It's okay to be. Also. In the illustrated embodiment, two sets of recesses 16, balls 19, etc. are provided, but only one set may be provided.

Note that instead of the ball 19, a pressing piece having a tapered surface at the locking portion and a rectangular cross section may be used, and instead of this, the hole 17 may also have a rectangular cross section.

In short, a locking mechanism 14 is provided that maintains the valve 6 in a lowered state relative to the support 8 while constantly applying a force to slide the valve 6 upward with respect to the support 8 using the elastic body 13. The locking mechanism 14 may be any mechanism that releases the clamping lock of the valve body by the impact of the molten metal to be injected on the valve 6. Note that the elastic body 13 is not limited to the case where a tension spring is provided between the rear side of the valve stem 6b and the top of the support body 8; 12
It may also be provided between the top of the

The support body 8 having the valve 6 therein is fixed only to the fixed mold 1 as described above, and half of its circumferential surface can be in close contact with or separated from the movable mold 2. A cylinder 23 is mounted upward on the top of the support 8,
A bracket 25 attached to the tip of the piston rod 24 of the cylinder 23 has a downwardly directed rod 26.
By attaching the valve and operating the cylinder 23, the return arm 22 horizontally projected from the block 15 is pushed down by the rod 26, and the valve 6 can be opened. Reference numeral 27 denotes a through hole provided in the support body 8 to allow the return arm 22 to pass through. In addition, cylinder 2
3 may be attached directly to the fixed mold 1, or it may be attached downward to the ceiling of the support 8, and the block 15
You may also press down directly. cylinder 23
and the rod 26 form an example of a valve opening device that opens the closed valve 6.

Since the mold degassing device according to the present invention is constructed as described above, when operating it, first align the fixed mold 1 and the movable mold 2, and then operate the cylinder 23 to open the valve 6. is opened, the pressing piece such as the ball 19 is engaged with the lower end of the concave portion 16 of the valve stem 6b, the fixed mold 1 and the movable mold 2 are brought together, and then the cylinder 23 is operated again. The rod 26 is raised so that it does not interfere with the closing operation of the valve 6.Of course, the valve 6 may be opened after the mold is clamped. At this time, the state is as shown in FIG. At this time, an exhaust passage is formed from the cavity 3 to the outside of the support 8 via the degassing path 4, the degassing groove 5, the passage 7, the valve chamber 10, and the discharge port 11. In this state, if the molten metal is injected into the cavity 3 by the injection operation, the gas in the cavity 3 will flow through the gas vent path 4 and the gas vent groove 5 as the cavity 3 is filled with the molten metal to be injected. It corresponds to the valve 6 section, and is discharged through the passage 7 from the upper side of the valve body through the valve chamber 10 and the discharge port 11. After the cavity 3 is almost filled with the molten metal to be injected, the molten metal rises in the gas vent groove 5 and hits the lower surface of the valve head 6a in the same way as the gas. At this time, the impact applied to the valve 6 is much larger than the impact applied by the gas to the valve 6, as the mass of the molten metal is much larger than the mass of the gas and has a large inertia, pushing the valve 6 upward. increase. At this time, due to the upward movement of the tapered part of the concave part 16, the ball 1
9 is pushed into the hole 17, and the valve stem 6b rises. Then, the valve head 6a comes into contact with the valve seat 9 to close the space between the passage 7 and the valve chamber 10, and stops the outflow of the molten material to be injected at the valve 6 position. At this time, the molten material to be injected is mixed with gas in the gas venting path 4 and the gas venting groove 5,
Even if it hits the valve body discontinuously in the form of droplets, the valve body is pushed up by the initial impact of the molten material, and then an elastic body such as a tension spring is pushed up by the molten material even without upward pressure. Since the valve 6 is maintained in the upper position by the action of the valve 13, the exhaust passage is reliably closed by the valve 6.

When the casting work is completed by pressurized cooling for a predetermined time with the valve 6 of the degassing device closed, the mold is opened and the cavity 3, degassing path 4, degassing groove 5, and passage 7 are removed. The solidified metal filled inside is separated from the valve 6 and the fixed mold 1, and taken out from the movable mold 2 together with the molded product by a product extrusion device (not shown).

Thereafter, the cylinder 23 is operated, the valve 6 is opened, and the valve head 6a and the like are cleaned with air. Then, at the next casting time, when the molds are aligned and the valve 6 is lowered, the valve 6 communicates the gas vent groove 5 and the passage 7 with the valve chamber 10, completing the preparation for the next casting. .

In the above embodiment, one set of the ball 19 and the recess 16 are provided, but alternatively, as shown in FIG.
Although it has been explained that two sets are provided in which the lower ends of the valve stems 6b and 6b are positioned, this means that the valve stems 6b and 6b have different positional relationships in the axial direction between the ball 19 and the lower end of the vertically grooved recessed part 16. If a plurality of valves 6, for example four sets, are provided around the valve 6, injection can be performed with various opening degrees of the valve 6 depending on the shape of the injection product.

Further, the degassing valve of the present invention can also be provided between the mold and the core. Even when it is provided between the fixed mold and the movable mold, it can be provided not only vertically above the mold, but also horizontally or diagonally.

As described above, the mold degassing device according to the present invention uses a valve equipped with an elastic body and a locking mechanism between the spool and the valve, so that gas with a small pressure to the valve can easily pass through, and the pressing force can be reduced. Since the molten material to be injected with a large amount of gas is reliably blocked, the cross-sectional area of the gas vent path or gas vent groove can be increased to facilitate and quickly vent gas during casting. The discharge passage is closed by the first impact of the discharge passage, and is kept closed by the elastic body, so that even if molten metal comes intermittently, the valve is reliably closed and its position is maintained. In addition, the valve always operates reliably and gas discharge during injection is performed reliably and easily.
Injection products with high strength can be easily obtained.

Further, in the present invention, since the pressing piece has the recessed portion located in the valve stem guide portion that guides the valve stem,
The pressing position of the pressing piece will not be misaligned. By the way, if this recess is provided in the block part that is screwed to the valve stem and the pressing piece is pressed into it, the difference in the amount of pressing force during setting and the action of the backlash of the threaded part can be used. It is difficult to always align the axis of the block portion with the axis of the valve stem, and the smoothness of the vertical movement of the valve may be affected. Therefore, in that case, it is necessary to sufficiently improve the machining accuracy of these sliding parts, but in the present invention, this machining accuracy is not so necessary and can be easily set.

When carrying out the present invention, the degassing effect can be further improved if it is used in combination with a reduced pressure injection method or a non-porous injection method in which the inside of the cavity is injected in an oxygen atmosphere.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. DESCRIPTION OF SYMBOLS 1... Fixed mold, 2... Movable mold, 3... Cavity, 5... Gas vent groove, 6... Valve, 7... Passage, 8... Support body, 11... Discharge port, 12... ... Valve stem guide portion, 13 ... Elastic body, 14 ... Locking mechanism, 16 ... Recessed portion, 18 ... Compression spring, 19 ...
... Ball, 22 ... Return arm, 23 ... Cylinder,
26... Rod.

Claims (1)

[Claims] 1. A gas vent groove led from the cavity on the separation surface of the mold, a valve that slides at the end of the gas vent groove, and a valve that is slidably supported and fixed to a part of the mold. a support mounted on the
A gas exhaust passage leading from the gas vent groove to the side surface of the valve part is provided, and the valve is opened with respect to an elastic body that applies force in the direction of closing the valve and a support that slidably supports the valve. A locking mechanism is provided between the support body and the valve, and the locking mechanism is locked in position and released as the valve closes, and a valve opening device is provided that pushes the closed valve into an open state. A degassing device for a mold in a molding machine attached to the support.