JPH0316219B2 - - Google Patents

Description

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

[Prior art] In an injection molding machine, etc., if gas remains in the cavity of the mold during injection molding, this causes the formation of cavities in the product, so it is necessary to exhaust the gas outside the mold. There is.

Conventionally, as the above-mentioned degassing device, there are two types of degassing devices: one in which an overflow or air vent is carved into the mold, and the one disclosed in Japanese Patent Application Laid-open No. 112646/1982. Since it is not possible to vent gas properly, there is a problem that cavities are formed inside the molded product.

As shown in FIG. 7, the latter device is biased upward by a spring e, and while the valve a is held open by the steel ball i and the spring j, the air in the cavity b flows through the bypass exhaust hole c. The molten metal is evacuated by a vacuum pump (not shown) through an exhaust port d, and then when the molten metal collides with the valve head a', the valve a is pushed up and the exhaust port d is closed.

However, in the above device, in order for valve a to move upward smoothly due to the collision of the molten metal, the valve head must be
It is necessary to provide a gap g between both sides of a′ and the affixed plate f, and in reality, the above gap g is provided, but if such a gap g is provided, the molten metal during injection will flow through the bypass exhaust hole. If the molten metal enters the valve body h from the exhaust port d through the gap g faster than it flows through the gap g, or if the molten metal adheres to the napper surface a of the valve head a, the valve operation becomes unstable and the molten metal enters the valve body h. Flow into. In addition, since a closing force acts on the valve due to the upward biasing force of the spring e and the pressure difference due to the exhaust, a holding force is required, so the structure is such that it can be adjusted using a steel ball i and a spring j. However, there are the following problems.

Holding force > collision force of molten metal + biasing force of spring e, valve does not operate. (Exhaust port does not close) If holding force < exhaust pressure difference + biasing force of spring e, the valve closes before exhaust is exhausted.

Because of the above, adjustment is troublesome and operation becomes unstable if there is variation in the collision force of the molten metal.

[Problem that the invention seeks to solve]

The present invention is an attempt to solve the above-mentioned problems, and includes a detection valve and an exhaust system valve in each exhaust passage led from the mold cavity. By providing both valves in communication with each other, the exhaust system valve is configured to close with air supplied from the air source when the detection system valve closes. Therefore, it is an object of the present invention to provide a degassing device that operates smoothly and can ensure degassing.

[Means for solving problems]

That is, the present invention provides a degassing device for an injection molding machine having a degassing valve mechanism installed to be able to close a degassing passage led from a cavity of a mold, wherein the degassing valve mechanism prevents the degassing of molten metal. It has a detection system valve that detects entry into the gas passageway and closes due to molten metal inertia, and an exhaust system valve that closes in response to the closing operation of the detection system valve. A first passage connected to the system valve is branched into a second passage connected to the exhaust system valve and has a higher flow resistance than the first passage, and the detection system valve can communicate with the first chamber A. a sensing valve body having a second chamber A formed therein; an air source connected to the second chamber for applying fluid pressure to the second chamber A; and an air source slidable relative to the sensing valve body. a detection valve provided in the first passage and having a valve head disposed opposite to the first passage, a rod portion, and a stepped portion formed in the rod portion; and a valve means engageably connected to the stepped portion. The valve means has contact means provided so as to be able to come into contact with the step, urging means for urging the contact means toward the detection valve body, and the contact means engages with the step. a detection piston that causes the first chamber A and the second chamber A to communicate with each other against the biasing force of the biasing means and applies the fluid pressure to the first chamber; The chamber is connected to a communication means, and the exhaust system valve is connected to an exhaust valve body and the exhaust valve body, and is provided so as to be connectable to the second passage for exhausting the gas in the cavity to the outside of the mold. an exhaust pipe provided so as to be slidable relative to the exhaust valve body; a rod portion provided at one end of the rod portion and disposed opposite to the second passage so as to communicate between the second passage and the exhaust pipe; an exhaust valve having a valve head that selectively shuts off the exhaust valve, and an exhaust piston provided at the other end of the rod portion, a third chamber U is provided between the exhaust piston and the exhaust valve body, The third chamber constitutes a degassing device in the injection molding machine connected to the communication means, and solves the above problem.

[Operation] The detection system valve is closed by the inertial force of the molten metal passing through the first passage during injection, and the closing operation of the detection system valve causes air to be supplied from the air source through the valve means and the communication means. However, the second room,
Sent to the first and third rooms. Therefore, the exhaust system valve is closed. In order to prevent the injected molten metal that has passed through the second passage of the exhaust system valve 2 from flowing into the exhaust system valve before the exhaust system valve is closed in response to the closing operation of the detection system valve, The second passage is set to be larger than the flow resistance of the first passage, and therefore, although the exhaust system valve is kept open as much as possible, the molten metal flows after the exhaust system valve closes. , so the molten metal will not enter the exhaust system valve.

〔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 FIGS. 1 to 6, a detection system valve 1 and an exhaust system valve 2 are arranged side by side. It is configured with

The detection system valve 1 is formed as follows.

Detection valve 3 having a valve head 3a at the lower end
is a valve hole 5 that perpendicularly penetrates the detection valve body 4.
is slidably inserted into the step 3b at the end of the valve.
A half-split stopper 6 is fitted into a counterbore 7 of the detection valve body 4 and held by a retaining ring 8 to prevent the detection valve 3 from coming off.

The detection valve body 4, the detection spacer 9, and the detection base 10 are fastened together with bolts (not shown), and the holding 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. 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. , an enlarged hole portion 12a formed by enlarging the outer end of the horizontal hole 12, and a bolt 15 fixed to the detection valve body 4 with a stopper to form the enlarged hole portion 1.
In the detection holder 16 with the opening 2a closed, a detection piston 18 screwed to the connecting rod 14 is slidably housed in a hole 17 provided coaxially with the horizontal hole 12. At the same time, the detection piston 18 is fixed to the opening of the hole 17 with a bolt 19 to close the hole 17 by a compression spring 21 interposed between the pressure plate 20 and the pressure plate 20 shown in FIGS. is biased to the right at
When the detection valve 3 is open, as shown in FIG. 2, the detection piston 18 closes the horizontal hole 12 by contacting the bottom surface of the enlarged hole 12a, and the steel ball 13 closes the side hole 12. The detection valve 3 is held in an open position by being in contact with a stepped portion 3c formed by providing a large diameter portion 3d in the detection valve 3, and in this state, the inside of the enlarged hole portion 12a and the horizontal hole 12 are held. The interior forms rooms A and B, respectively.

Further, an elbow 22 is airtightly screwed onto the detection holder 16, and the elbow 22 is connected to an air source such as a compressor (not shown) through a hose 23, and air is supplied from the air source to the chamber A. A solenoid valve (not shown) is installed between the air source and the elbow 22.

Further, an elbow 25 is airtightly connected to the horizontal hole 12, that is, a hole 24 provided in communication with the chamber A, and a hose 26 is used to communicate the elbow 25 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.

Exhaust valve body 27 and exhaust valve guide 28
The exhaust spacer 29 and the exhaust base 30 are coaxially fixed with bolts (not shown), and the exhaust hole 31 of the exhaust valve body 27 and the valve hole 32 of the exhaust valve guide 28 have a valve head 33a at the lower end. An exhaust valve 33 is inserted into the exhaust hole 31 so as to be slidable in the axial direction and can be opened and closed, and a piston stopper 34 is provided at the upper end of the exhaust valve 33 to move the exhaust valve 33 upward. Exhaust pistons 35 are fixed respectively. For convenience, the exhaust valve body 27, exhaust valve guide 28, exhaust spacer 29, and exhaust base 30 are collectively referred to as the "exhaust valve body" in the claims.

The piston stopper 34 is formed in half,
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 28. The exhaust valve guide 28 has two horizontal holes 36, which communicate with the valve holes 32, respectively.
36 are arranged oppositely, and steel balls 37 and 37 rotate, respectively.
In addition, each horizontal hole 3 is
Compression springs 40, 4 are interposed between respective presser plates 39, 39 fixed to the openings of 6, 36 with bolts 38.
0, each of the steel balls 37, 37 is connected to the exhaust valve 33.
The exhaust valve 33 is held in the open position shown in FIGS. 3 and 6 by being biased toward the sides and detachably engaged with the annular groove 33b.

Further, an elbow 4 is provided on one side of the exhaust spacer 29.
1 is screwed in an airtight manner, and the hose 26 of the detection system valve 1 is connected to the elbow 41, thereby connecting the exhaust spacer 2 and the exhaust spacer 2.
The chambers formed inside 9 are communicated with each other.

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

Further, an exhaust hole 42 is provided on one side of the exhaust valve body 27, 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 pump is controlled by a limit switch solenoid valve (not shown).

Further, the upper side edges of the valve head 33a in the exhaust valve 33 and the lower end opening edge of the exhaust hole 31 in the exhaust valve body 27 are formed by tapered surfaces 33, respectively.
c, 31a and both tapered surfaces 33c and 31a.
A is provided so that the exhaust port 44 is hermetically closed when it comes into contact with the exhaust port 44.

Further, 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 both the valves 1, 2
The lower ends of the main bodies 4 and 27 are inserted so as to be slidable in an airtight manner in the vertical direction by providing insertion grooves 51 and 52 in a plate 50 provided on the separation surface between the fixed mold 48 and the movable mold 49 in the mold 47. It is provided so that it can be moved up and down a fixed distance by a hydraulic cylinder (not shown).

Further, exhaust passages 54 and 55 are led from cavities 53 provided in the separation surface of the mold 47, respectively, and the respective insertion grooves 51 and 55 are connected to each other.
52 are in communication, the exhaust path 5
4 and the detection system valve 1, and the exhaust path 55 and the exhaust system valve 2, respectively.
The side exhaust passage 54 is provided so that when the molten metal filling the cavity 53 advances straight and collides with the valve head 3a, the detection valve 3 is moved upward and closed. On the other hand, in order to provide a time delay (for example, about 5/1000 seconds) to the molten metal until the exhaust valve 2 completes its operation, the surface area of the exhaust passage 55 on the exhaust system side valve 2 side is increased without changing its cross-sectional area. For example, 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 while the exhaust system valve 2 is closed, so that the molten metal does not easily flow. Note that the exhaust passages 54 and 55 correspond to the first passage and the second passage described in the claims, respectively.

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

When the molten metal filling the cavity 53 reaches the exhaust passage 54 and 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. Ru.

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

When the detection system valve 1 closes, the steel ball 13 is pressed by the stepped portion 3c of the detection valve 3.
The steel ball 13, the connecting rod 14, and the detection piston 18 move to the left as shown in FIG. 4 against the spring force, whereby chambers A and B communicate with each other, and at this time, air is supplied from the air source to chamber A. The air is sent from the hole 24 to the elbow 2.
5. The air flows through the hose 26 to the chamber U of the exhaust system valve 2, and the exhaust piston 35 and the piston stopper 34 are pushed up by this air pressure.

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

The molten metal passes through the exhaust path 55 and reaches the exhaust system valve 2, but since the exhaust system valve 2 is already closed, the molten metal does not flow into the valve from the exhaust port 44.

When the filling of the molten metal is completed, the solenoid valve (not shown) is changed for the first time, and the elbow 2 of the detection holder 16 is closed.
2, and the air in chambers A and B of the detection valve 1 and chamber C of the exhaust valve 2 is released to the atmosphere. Next, a casting machine (not shown) is operated to open the mold, and a hydraulic cylinder (not shown) is operated to move the degassing device upward as shown in FIG. Detection valve 3 of both the detection system and exhaust system valves 1 and 2 of the degassing device moved upward at the same time
The exhaust valve 33 returns to the open state due to the contraction force when the molten metal solidifies.

After that, the normal injection molding cycle (molded product removal → mold clamping) is carried out, the degassing device is lowered by the hydraulic cylinder, the solenoid valve is switched again, and with air being supplied to the chamber A of the detection valve 1, Prepared for 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 is operated by the inertia. Then, the detection system valve 1 is closed, and this closing operation opens the valve means 11, and the exhaust system valve 2 is closed by the air supplied from the air source.
Exhaust passages 5 on the detection system valve 1 side are respectively led from
4, the molten metal can go straight to the detection system valve 1, while the exhaust passage 55 on the exhaust system valve 2 side is formed in a stepped shape or the like without changing the exhaust cross-sectional area to increase the surface area, By changing the flow direction of the molten metal and increasing the flow resistance due to the contact resistance and cooling effect of the molten metal, the molten metal is made difficult to flow, so that when the molten metal passes through the exhaust passage 55 and reaches the exhaust system valve 2, the exhaust system Since the valve 2 is already closed, the molten metal will not flow into the exhaust system valve 2 at all, and therefore the operational trouble caused by the molten metal flowing into the valve in the conventional example can be solved, and the valve opening/closing operation can be improved. This has the advantage that degassing can be carried out smoothly and can be done smoothly and reliably.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing an embodiment of a gas venting device in an injection molding machine according to the present invention;
Figures 2 and 3 are - lines in Figure 1, -
FIG. 4 is a vertical side view showing the detection system valve in the same embodiment in a closed state;
Fig. 5 is a vertical side view showing the closed state of the exhaust system valve in the same embodiment, Fig. 6 is a partially sectional front view showing the same embodiment in an elevated state, and Fig. 7 is a conventional gas FIG. 3 is a longitudinal sectional front view showing the extraction device. 1...Detection system valve, 2...Exhaust system valve, 1
1... Valve means, 47... Mold, 53... Cavity, 54, 55... Exhaust path.

Claims (1)

[Scope of Claims] 1. A gas venting device for an injection molding machine having a gas venting valve mechanism attached to be able to close a gas venting path led from a cavity 53 of a mold 47, 48, comprising: has a detection system valve 1 that detects the entry of molten metal into the gas vent passage and closes due to the inertia of the molten metal, and an exhaust system valve 2 that closes in response to the closing operation of the detection system valve 1. The gas vent passage is branched into a first passage 54 connected to the detection system valve 1 and a second passage 55 connected to the exhaust system valve 2 and having a flow resistance greater than that of the first passage, The detection system valve 1 includes a detection valve body 4 that has a first chamber A and a second chamber A formed to be able to communicate with the first chamber A, and is connected to the second chamber A in order to apply fluid pressure to the second chamber A. a valve head 3 slidably provided with respect to the detection valve body 4 and disposed opposite to the first passage;
a, the rod portion, and the stepped portion 3 formed on the rod portion.
a detection valve 3 having a detection valve 3c and 3d; and a valve means 11 that is engageably connected to the stepped portions 3c and 3d, and the valve means has an abutment provided so as to be able to come into contact with the stepped portion. means 13 and 14; a biasing means 17 for biasing the corresponding contact means toward the detection valve body; and a biasing means 17 for biasing the corresponding contact means toward the detection valve body; It has a detection piston 18 that communicates the first chamber A and the second chamber A and applies the fluid pressure to the first chamber, and the first chamber is connected to communication means 24, 25, and 26, and the exhaust gas is connected to the first chamber A and the second chamber A. The system valve 2 includes exhaust valve bodies 27, 28, 29, and 30, and is connected to the exhaust valve body and has a cavity 53.
The second passage 5 is used to exhaust the gas inside the mold to the outside of the mold.
an exhaust pipe 43 provided so as to be connectable to the second passage 55; a rod part provided slidably with respect to the exhaust valve body; The exhaust valve 33 has a valve head 33a that selectively blocks communication between the two passages and the exhaust pipe 43, and an exhaust piston 35 provided at the other end of the rod portion, and the exhaust piston and the exhaust valve body A degassing device for an injection molding machine, characterized in that a third chamber (C) is provided between and connected to the communication means.