JPS62214861A - Gas venting device for injection molding machine - Google Patents

Abstract

PURPOSE:To make gas venting sure by providing detecting line valves and evacuation line valves to an evacuation path of a cavity, and closing the evacuation line valve by the inertial force of a molten metal, then closing the evacuation line valve with a time delay. CONSTITUTION:The detecting line valve 1 and the evacuation line valve 2 are juxtaposed to the evacuation path of a gas venting device and a valve means 11 is provided to one side part of the detecting valve body 4 so that the valve means 11 makes an opening operation by the closing operation of the detecting valve 3. The valve 3 moves upward and the detecting line valve 1 is closed when the molten metal filled into the cavity 53 collides against a valve head 3a upon arrival at the evacuation path 54. The valve means 11 is then opened and the evacuation line valve 2 is closed with the time delay by air. The inflow of the molten metal into the evacuation line valve 2 is thoroughly prevented by the above-mentioned method, by which the gas venting is smoothly and surely executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for extracting gas from a mold cavity in a die casting machine, an injection molding machine, etc. during injection molding.

[Conventional technology]

In an injection molding machine or the like, if gas remains in the mold cavity during injection molding, this causes the formation of blowholes in the product, so it is necessary to discharge the gas to the outside of the mold.

Conventionally, as the above-mentioned gas venting device, there is one in which an overflow or an air vent is carved into a mold, and one in which an overflow or an air vent is carved into a mold, and the other is a device in which an overflow or an air vent is carved into a mold.
The method disclosed in Japanese Patent No. 112646 is known, but the former method does not allow sufficient degassing and has the problem of forming cavities inside the molded product.

In the latter device, as shown in FIG. 7, while the nozzle a, which is urged downward by the spring e, is held open, the air in the cavity b flows from the bypass exhaust hole C to the exhaust port d. The molten metal is then evacuated by a vacuum pump (not shown), and then when the molten metal collides with the valve head a', the valve a
is pushed up to close the exhaust port d.

However, in the above device, in order for the valve a to move upward smoothly due to the collision of the molten metal, it is necessary to provide a gap g between both sides of the valve head a' and the plate f. In reality, the above-mentioned gap g is provided, but if such a gap g is provided, the molten metal during injection passes through the above-mentioned gap g faster than flowing through the bypass exhaust hole C and flows from the exhaust port d into the valve body. If it enters the valve or adheres to the tapered surface a'' of the valve head a', the valve operation becomes unstable and the molten metal hVc in the valve body flows in. Also, the valve requires a holding force because the pressure difference caused by the exhaust acts on the valve to close it. Therefore, it is constructed so that it can be adjusted using a steel ball i and a spring j, but it has the following problems.

■ If the holding force is the collision force of the molten metal, the valve will not operate. (Exhaust port does not close) ■ If the holding force is large and the exhaust pressure difference is large, the valve closes before exhaust is exhausted.

Because of the above, adjustment is troublesome, and operation becomes unstable if there is a collision force of the molten metal (luck).

[Problem that the invention seeks to solve]

The present invention is an attempt to solve the above problem, and includes a detection system valve and an exhaust system valve in each exhaust path led from the mold cavity, and the detection system valve is closed by the inertia of the molten metal during injection. and the two valves are provided in communication with each other, and when the detection system valve closes, the exhaust system valve is configured to close with a time delay using air supplied from an air source. The object of the present invention is to provide a degassing device that operates smoothly and ensures reliable degassing.

[Means for solving problems]

That is, the present invention provides a detection system valve and an exhaust system valve in each exhaust path led from the mold cavity, and the detection system valve is closed by the inertia of the molten metal during injection, and Valve means is provided that can be opened by the closing operation of the detection system valve against the biased spring force, and the exhaust system valve can be closed by air supplied from the air source through the valve means. Both the detection system and exhaust system valves are formed in communication, and the injection molten metal is prevented from flowing into the exhaust system valve while the exhaust system valve is closed with a time delay with respect to the closing operation of the detection system valve. The above-mentioned problem was solved by configuring the exhaust passage on the exhaust system valve side in a stepped manner so that the flow of the molten metal is slower than that on the detection system valve side.

〔Example〕

Hereinafter, one embodiment of the degassing device for an injection molding machine according to the present invention will be described in detail based on the drawings.
As shown in the figure, a detection system valve 1 and an exhaust system valve 2 are arranged side by side.

The detection system valve 1 is formed as follows.

A detection valve 3 having a valve head 3a at the lower end is slidably inserted into a valve hole 5 vertically penetrating the detection valve body 4, and a stopper 6 split in half at a step 3BLC at the end of the valve is inserted.
is fitted into a counterbore 7 of the detection valve body 4 and held by a retainer ring 8 to prevent the detection valve 3 from being removed.

The above detection valve body 4, detection spacer 9 and detection pace 1
0 is fastened with a bolt (not shown), and the retaining ring 8 is sandwiched between the detection valve body 4 and the detection spacer 9.

Further, a valve means 11 is provided on one side of the detection valve body 4.
is provided. This valve means 11 is formed as follows so that when the detection valve 3 is closed, an upward step 3C provided on the valve 3 is opened.

A horizontal hole 12 is provided in one side of the detection valve body 4 in communication with the valve hole 5, and a steel ball 13 and a connecting rod 14 are slidably housed in the horizontal hole 12 in order from the inside. There is an enlarged hole portion 12a formed by enlarging the outer end of the horizontal hole 12.
The detection holder 16 is fixed to the detection valve body 4 with bolts 15 to close the opening of the enlarged hole 12a, and the hole 17 coaxial with the horizontal hole 12 has a A detection piston 18 screwed to the connecting rod 14 is slidably installed inside the connecting rod 14, and the detection piston 18 is fixed to the opening of the hole 17 with a bolt 19 to close the hole 17. It is biased to the right in FIGS. 2 and 4 by a compression spring 21 interposed between the presser foot Iida and the presser foot Iida, and when the detection valve 3 is open,
As shown in FIG. 2, the detection piston 18 has an enlarged hole 12
The steel ball 13 closes the horizontal hole 12 by contacting the bottom surface of the detection valve 3, and the steel ball 13 also contacts the step portion 3C formed by providing the large diameter portion 3d in the detection valve 3. is held in the open position, and in this state, the inside of the enlarged hole part 12a and the inside of the horizontal hole 12 are respectively filled with chambers ■,
■It forms.

Further, an elbow ρ is airtightly screwed onto the detection holder 16, and the elbow n is connected to an air source such as a compressor (not shown) through a hose, and air is supplied from the air source to the chamber (2). It is like that.

In addition, the horizontal hole 12, that is, the hole 24 provided in communication with the chamber
An elbow 5 is airtightly connected to the exhaust system valve 2, and a hose 26 communicates the elbow 5 with a portion of the exhaust system valve 2, which will be described later.

On the other hand, the exhaust system valve 2 is formed as follows.

The exhaust valve body n, the exhaust valve guide 4, the exhaust spacer 4, and the exhaust base holder are coaxially fixed with bolts (not shown), and the valve hole 31 of the exhaust valve body moss
An exhaust valve 33 having a valve head 33a at its lower end is inserted into the valve hole 32 of the exhaust valve guide so as to be slidable in the axial direction, and the valve hole 31 can be opened and closed. At the upper end, a piston stopper and an exhaust piston 35 for moving the exhaust valve 33 upward are fixed.

The piston stopper is formed in half, and the exhaust piston 35 is fixed to the exhaust valve 33 by aligning the end of the exhaust valve 33 and the exhaust piston 35 and tightening them with bolts (not shown).

Further, an annular groove 33b is provided around a portion of the exhaust valve 33 located within the exhaust valve guide path. The exhaust valve guide 4 has two horizontal holes 36 and 36 that communicate with the valve holes 32 and are opposed to each other.
7.37 is rotatably and slidably installed inside, and a compression spring 40.4 is interposed between 8 retaining plates 39.39 fixed to the openings of the respective horizontal holes 36.36 with bolts 38.
0, the steel balls 37, 37 are each urged toward the exhaust valve 33 side and are removably engaged in the annular groove 33b, so that the exhaust valve 33 is shown in FIGS. 3 and 6. held in the open position.

Furthermore, an elbow 41 is airtightly screwed onto one side of the exhaust spacer 29, and the hose 26 of the detection system valve 1 is connected to the elbow 41. The chambers formed inside the exhaust spacer 4 are communicated with each other.

Further, the exhaust piston 35 and the piston stopper 34 are
It is formed in a shape that can be pushed up by air supplied from the elbow 41 to the chamber (2).

Further, an exhaust hole 42 is provided on one side of the exhaust valve body, and the exhaust hole 42 is connected to a vacuum pump (not shown) so as to be able to exhaust gas to the outside via an exhaust pipe 43.
The timing of vacuum suction by the vacuum pump is controlled by a limit switch and a solenoid valve (not shown).

Further, the valve head 33 a of the exhaust valve 33
and the upper side edges of the exhaust valve body n.
The lower end opening edges of each of the tapered surfaces 33C and 131a are formed on the tapered surfaces 33C and 131a, so that the exhaust port 44 is hermetically closed when the tapered surfaces 33c and 31a come into contact with each other.

Furthermore, the detection system valve 1 and the exhaust system valve 2 described above are removably assembled integrally with the connecting fitting 45 and the holding plate 46, and the lower ends of the main bodies 4 and n of both valves 1.2 are the fixed mold 18 and the movable mold 49 in the mold 47.
Insertion grooves 51 and 52 are provided in the affixed plate 50 provided on the separation surface of the plate, and the plate is inserted so as to be slidable airtightly in the vertical direction. There is.

Moreover, the cavity 5 provided in the separation surface part of the mold 47
Exhaust passages 54 and 55 are provided for each of the 8 exhaust passages 5.
4.55 and the respective insertion grooves 51.52, the exhaust passage 54 and the detection system valve 1 are communicated with each other, and the exhaust passage 55 and the exhaust system valve 2 are communicated with each other. The exhaust passage 54 on the l side is provided so that the detection valve 3 is moved upward and closed when the molten metal filling the cavity 53 advances straight and collides with the valve head 3a. In order to provide a time delay (for example, about 5/1 oOo seconds) in the operation of the exhaust system valve 2, the exhaust passage 55 on the exhaust system valve 2 side has a large surface area, for example, without changing its cross-sectional area. As shown in the figure, the molten metal is formed in a stepped shape or the like so that the molten metal does not reach the exhaust system valve 2 during the closing operation of the exhaust system valve 2, thereby making it difficult for the molten metal to flow.

Next, the operation of the present invention will be explained.

The molten metal filling the cavity 53 reaches the exhaust passage 54,
When it collides with the valve head 3a, the collision force or pressure causes the detection valve 3 to move upward by a distance Z shown in FIG. 4, and the detection system valve 1 is closed.

At this time, even in low-speed injection, the molten metal moves straight through one exhaust passage 54 without flowing into the other exhaust passage 55, so only the gas is guided to the exhaust system valve 2 via the exhaust passage 55, and the vacuum pump is discharged to the outside from the exhaust hole 42.

When the detection system valve 1 is closed, the steel ball 13 is pressed by the stepped portion 3C of the detection valve 30, so the steel ball 13, connecting rod 14, and detection piston 18 are moved against the spring force as shown in FIG. Move to the left, thereby connecting chambers ■ and ■,
At this time, air supplied from the air source to the chamber flows from the hole 24 through the elbow 5 and the hose 26 to the chamber 2 of the exhaust system valve 2, and the second air pressure pushes up the exhaust piston 35 and the piston stopper. Ru.

Therefore, by moving the exhaust valve 33 upward,
The exhaust port 44 is closed by the valve head 33a, and the exhaust system valve 2 is operated to close.

The molten metal passes through the exhaust passage 55 and reaches the exhaust system valve 2, but since the exhaust system valve 2 is already closed, the exhaust port 44
No molten metal will flow into the valve.

When the molten metal solidifies, a casting machine (not shown) is activated, and when the mold is opened, a hydraulic cylinder (not shown) is activated to move the degassing device upward as shown in FIG. 6. Both the detection system and exhaust system valves of the degassing device moved upward at the same time.
The detection valve 3 and the exhaust valve 33 of No. 2 return to the open state due to the contraction force when the melt oil solidifies.

Thereafter, a normal injection molding cycle (molded product removal → mold clamping) is performed, and the degassing device is lowered by a hydraulic cylinder to prepare for the next molding.

〔Effect of the invention〕

As explained above, since the degassing device in the injection molding machine according to the present invention is configured, the exhaust valve is not closed by the inertia of the molten metal during injection, but the detection system valve is closed by the inertia. l is operated to close, and this closing operation opens the valve means 11,
Exhaust system valve 2 by air supplied from an air source
In addition, the exhaust passages 8 on the detection system valve 1 side led from the cavities 53 respectively allow the molten metal to proceed straight to the detection system valve l, while the exhaust passages 8 on the exhaust system valve 2 side The exhaust passage 55 does not change the exhaust cross-sectional area (by increasing the surface area by forming it in a stepped shape, changing the flow direction of the molten metal, increasing the flow resistance due to the contact resistance of the molten metal or the cooling effect, etc.). Since the molten metal is formed so that it is difficult to flow, when the molten metal passes through the exhaust passage 55 and reaches the exhaust system valve 2, the exhaust system valve 2 is already closed, so that the molten metal does not flow into the exhaust system valve 2 at all. Therefore, the operational troubles caused by molten metal flowing into the valve in the conventional example can be eliminated, the valve can be opened and closed smoothly, and there is an advantage that degassing can be performed smoothly and reliably.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing an embodiment of a degassing device in an injection molding machine according to the present invention, and FIGS. 2 and 3 are lines 4 is a longitudinal sectional side view showing the detection system valve in the same embodiment in a closed state; FIG. 5 is a longitudinal sectional side view showing the exhaust system valve in the same embodiment in a closed state; FIG. 6 is a partially sectional front view showing the same embodiment in an elevated state, and FIG. 7 is a longitudinal sectional front view showing a conventional gas venting device. l...Detection system valve 2...Exhaust system valve 11
...Valve means 47...Mold 53...
Cavity 54.55 -- Exhaust passage Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Procedure Correction February 27, 1988

Claims (1)

[Claims] A detection system valve and an exhaust system valve are provided in each exhaust path led from the mold cavity, and the detection system valve is closed by the inertia of the molten metal during injection, and the detection system valve is closed. Valve means is provided that can open against the biased spring force upon operation, and the exhaust system valve can be closed by air supplied from an air source through the valve means. The exhaust system is configured to communicate with both valves of the detection system and to prevent the injected molten metal from flowing into the exhaust system valve while the exhaust system valve is closed with a time delay with respect to the closing operation of the detection system valve. 1. A gas venting device for an injection molding machine, characterized in that an exhaust passage on the valve side is provided in a stepped manner so that the flow of the injected molten metal is slower than that in the exhaust passage on the detection system valve side.