JP3389100B2 - Rotary shut-off nozzle of metal injection molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shutoff nozzle of a metal injection molding machine for heating and melting a low melting point metal or the like and injecting it into a mold to obtain a molded product.

[0002]

2. Description of the Related Art Generally, in an injection molding machine using a resin or the like as a molding material, a rotary valve is provided between an injection nozzle and a heating cylinder, and the rotary valve is rotated at the end of the injection process. It is configured to shut off the runner and stop the supply of the molten material.

FIG. 3 shows a rotary shut-off nozzle according to a conventional example, in which a valve block 130 is interposed between a heating cylinder 110 and an injection nozzle 120, and the injection nozzle 12 penetrates through the valve block 130.
The valve block runner 131 communicating with the No. 0 injection nozzle runner 121 is opened and closed by the rotary valve 140.

The rotary valve 140 has a cylindrical main body, and the main body is rotatably fitted in a cylindrical hole 130a formed in the valve block 130. The body of the rotary valve 140 is provided with a through hole 141 as a runner, which crosses the cross section in the radial direction.

A part of the main body of the rotary valve 140 is projected to the outside of the valve block 130, and the lever 142 attached thereto is rotated by a linear actuator 144 composed of a fluid pressure cylinder or the like via a coupling fitting 143. As shown in FIG. 3A, the molten resin or the like supplied from the heating cylinder 110 is injected with the through hole 141 of the rotary valve 140 and the valve block runner 131 in communication with each other.

After the injection process is completed, the linear actuator 144 is driven to rotate the lever 142 by a predetermined angle, and as shown in FIG.
The valve block runner 131 is blocked by the outer peripheral surface of the. That is, the rotary valve 140 is rotated to a rotation position where the through hole 141 of the rotary valve 140 does not communicate with the valve block runner 131. In this way, the supply of molten resin is stopped except when injection is performed,
The resin is prevented from flowing out of the injection nozzle 120.

[0007]

However, according to the above-mentioned conventional technique, a molding material having a high viscosity such as resin,
If the melting temperature is also about 200 to 300 ° C., the molten material does not leak around the rotary valve, the molten material flows out of the apparatus, and the rotary valve can be operated without trouble such as malfunction. However, it cannot be applied to a metal injection molding machine using a light metal or the like as a molding material.

More specifically, when the molding material is a low melting point metal such as aluminum, magnesium, zinc, tin, lead, etc., the molten state of these is a low-viscosity liquid which passes through the runner. The speed is 3 to 10 times faster than that of resin, and the pressure is high.

Therefore, even if a seal ring or the like is provided to prevent the molten material from leaking from the periphery of the rotary valve, the liquid molten metal supplied from the heating cylinder at high speed and high pressure leaks to the periphery of the body of the rotary valve. Is difficult to reliably prevent, and the leaked amount causes malfunction of the rotary valve. In addition, since the temperature of the molten material is as high as around 600 ° C., if the molten material flows out of the valve block, there is a risk of sudden oxidation or explosion due to combustion, which is very dangerous for the operator.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and is capable of efficiently recovering the molten material flowing out to the periphery of the rotary valve and preventing troubles caused thereby. It is an object of the present invention to provide a rotary shutoff nozzle for a metal injection molding machine having high performance and high safety.

[0011]

In order to achieve the above object, a rotary shutoff nozzle of a metal injection molding machine of the present invention comprises an injection nozzle for injecting a molten material and first and second connection holes. A rotary valve, a valve block having a cylindrical hole rotatably accommodating the rotary valve, and drive means for rotationally driving the rotary valve, wherein the valve block communicates with the injection nozzle. The rotary passage includes a runner and a second runner having one end opened to the cylindrical hole and the other end opened to the outside.
The first connecting hole in the first rotational position.
To connect the discharge port of the heating cylinder to the first runner,
In the second rotational position, the second connection hole causes the
The discharge port of the heating cylinder is connected to the second runner.
It is characterized in that it is configured to .

[0012]

The valve block may be provided with a recess for accommodating the molten material leaking into the cylindrical hole and an escape runner for guiding the molten material in the recess to the second runner.

Heating means for heating the rotary valve and the valve block may be provided.

[0015]

[Operation] The rotary valve is rotated by the driving means,
At the first rotation position, the first connection hole is connected to the first runner of the valve block, the molten material is supplied to the injection nozzle, and the molten material is injected into the mold. At the end of the injection process, the rotary valve is rotated by a predetermined angle to stop the supply of the molten material.

The molten material leaking to the outer peripheral surface of the rotary valve is collected directly in the second runner of the valve block or through the escape runner, and is taken out of the valve block to be safely processed. It

During and after the injection process, there is no possibility that molten material such as high-temperature and high-pressure molten metal will be ejected to the outside of the rotary valve, and work safety can be greatly improved. Also, troubles such as malfunction of the rotary valve due to leaked molten material can be avoided.

When performing the purging operation for purging the molten material of the heating cylinder, the rotary valve is rotated to the second rotational position where the second connection hole communicates with the discharge port of the heating cylinder, and the purged molten material is removed. Collect from the second runner in the valve block.

Compared with the case where the injection nozzle is retracted from the mold and the molten material is recovered from the injection port of the injection nozzle, the work is simple and the work efficiency can be greatly improved.

In this way, it is possible to realize a high-performance metal injection molding machine which is highly safe for workers, has good working efficiency, and is free from troubles such as malfunction of the rotary valve.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows one embodiment.
A valve block 30 is provided between the heating cylinder 10 and the injection nozzle 20, and the valve block runner 31 is a first runner that penetrates the valve block 30 and communicates with the injection nozzle runner 21 of the injection nozzle 20. The rotary valve 40
Open and close by.

The rotary valve 40 has a cylindrical main body, and the main body is rotatably fitted in the cylindrical hole 30a of the valve block 30. The main body of the rotary valve 40 has a rotary valve runner 41, which is a first and a second connection hole.
a and 41b (see FIG. 2) are provided, and these cross the cross section of the main body of the rotary valve 40 substantially parallel to each other.

A part of the main body of the rotary valve 40 is projected to the outside of the valve block, and a lever 42 attached to the rotary valve 40 is connected to a lever 43 by a linear actuator 44 which is a driving means composed of a fluid pressure cylinder or the like via a coupling fitting 43. Rotate. As shown in FIGS. 1 and 2A, the first rotary valve runner 41a and the valve block runner 3 are provided.
In the state where 1 is in communication with each other, a molten material such as molten metal supplied from the heating cylinder 10 is injected.

When the injection process is completed, the linear actuator 44 is driven to rotate the lever 42 by a predetermined angle,
As shown in FIG. 2B, the valve block runner 31 is blocked by the outer peripheral surface of the main body of the rotary valve 40.
That is, the rotary valve 40 is rotated to a position where the first rotary valve runner 41 a of the rotary valve 40 does not communicate with the valve block runner 31. In this way, molten material is prevented from flowing out of the injection nozzle 20 except when injection is being performed.

A cartridge heater 51 is embedded in the center of the rotary valve 40, and a plurality of cartridge heaters 52 to 55 are embedded in the valve block 30 so as to surround the rotary valve 40 at equal intervals. These cartridge heaters 51 to 51 which are heating means
By 55, the valve block 30 and the rotary valve 40 are maintained in a predetermined heating state.

The second rotary valve runner 41b is provided for purging the molten material during the injection molding operation as described later. The first and second rotary valve runners 41a and 41b are arranged on both sides of the central cartridge heater 51.

One end of the valve block runner 31 is connected to the discharge port of the heating cylinder 10 and the other end thereof opens into the cylindrical hole 30a of the valve block 30.
And one end is opened to the cylindrical hole 30a of the valve block 30, and the other end is a nozzle side runner 31b connected to the injection nozzle runner 21 of the injection nozzle 20. In addition to these, one end of the valve block 30 opens into the cylindrical hole 30a of the valve block 30, and the other end is a second runner that is open to the outside of the valve block 30.
Have.

If the molten material supplied from the heating cylinder 10 is a liquid such as aluminum, magnesium, zinc, tin or lead which is liquid at high temperature and high pressure, the rotary valve 4 is used.
It is unavoidable that the leaked molten metal leaks to the outer peripheral surface of the body of No. 0, and the leaked molten metal spouts from the opening end of the cylindrical hole 30a of the valve block 30 to the outside or interferes with the rotation of the rotary valve 40 to cause malfunction. May cause trouble.

Particularly, when a high pressure is generated on the heating cylinder 20 side while the rotary valve 40 is closed after the injection process is completed, a high-pressure molten material is ejected from around the rotary valve 40 to cause an explosion or the like. Extremely dangerous for workers. Also, during the injection process, the injection nozzle runner 21
Even if the clogs are blocked, the molten material continuously supplied from the heating cylinder 20 is ejected from the valve block 30 to cause the above trouble.

Even if the rotary valve 40 is provided with the seal ring 46 for preventing leakage, the molten material cannot be completely stopped from flowing toward the open end of the cylindrical hole 30a of the valve block 30.

Therefore, the molten material recovery runner 31c opening to the outer peripheral surface of the rotary valve 40 is connected to the valve block 30.
Is installed in the valve block 30 to directly collect a part of the molten material leaked around the rotary valve 40.
A recess 32 for accumulating the molten material flowing out at the open end of the cylindrical hole 30a, and an escape runner 33 for introducing the molten material accumulated in the recess 32 into a molten material recovery runner 31c.
To provide.

The molten material returned from the recess 32 of the valve block 30 through the runner 33 to the molten material recovery runner 31c is leaked directly to the molten material recovery runner 31c as described above. Along with the minutes, the molten material recovery runner 3
After being collected in an unillustrated receiving box attached to the open end of 1c, it is safely processed.

Since all the molten material leaking from the rotary valve can be collected and safely processed in the receiving box or the like, the work safety is impaired by the leaking molten metal or the like as in the conventional example, or the rotary valve is rotated. There is no risk of trouble such as valve malfunction.

This makes it possible to realize a metal injection molding machine having high safety and high performance.

Since the molten metal has a risk of being rapidly oxidized or burned in the air, it is desirable that the receiving box and the like be hermetically sealed and filled with an inert gas.

The open end of the cylindrical hole 30a of the valve block 30 is closed by a flange 40a protruding to the outer peripheral surface of the main body of the rotary valve 40, and the holding plate 40b for fixing the rotary valve 40 to the valve block 30 is
The screw 40c fixes the valve block 30.
The lever 42 is attached to a square shaft 40d formed on the end of the main body of the rotary valve 40, and is fixed by a washer 40e and a holding bolt 40f. Also, presser bolt 4
A hole is provided in the center of 0f for passing the wiring of the cartridge heater 51.

Next, the operation of the rotary valve 40 will be described.

As described above, in the injection step, the cylinder side runner 31a of the valve block 30 and the nozzle side runner 3 are provided.
The rotary valve 4 is placed at a rotation angle (first rotation position) where the first rotary valve runner 41a communicates with the first valve 1b.
0 is located (see (a) of FIG. 2). Heating cylinder 10
The molten material supplied from (1) is injected from the injection nozzle runner 21 through the cylinder side runner 31a of the valve block 30, the rotary valve runner 41a and the nozzle side runner 31b of the valve block 30.

During this time, if the molten material is blocked in the injection nozzle runner 21 and the nozzle side runner 31b of the valve block 30,
Although the molten material leaks to the outer peripheral surface of the main body of the rotary valve 40, all such leaked material escapes directly or through the recess 32 at the open end of the valve block 30.
And the like, and is introduced into the molten material collecting runner 31c, from which it is collected in a receiving box or the like and safely processed.

At the end of injection, the linear actuator 44
Is driven to rotate the rotary valve 40 by a predetermined angle, and the first and second rotary valve runners 41a and 41b are rotated.
2 is in a closed state as shown in FIG.

At this time, when a high pressure is generated in the heating cylinder 10, the molten material also leaks to the outer peripheral surface of the rotary valve 40, but is introduced into the molten material recovery runner 31c and recovered in the receiving box in the same manner as above. .

When purging the molten material during the injection molding operation, as shown in FIG. 2 (c), the second rotary valve runner 41b is used to collect the molten material and the cylinder side runner 31a of the valve block 30. The injection valve 20 is retracted from the mold after rotating the rotary valve 40 to the second rotation position where the runner passage 31c communicates. The molten material purged from the heating cylinder 10 is recovered from the second rotary valve runner 41b through the molten material recovery runner 31c into a receiving box or the like.

If there is no such recovery means, it is necessary to retract the injection nozzle 20 from the mold and prepare a shield such as a purge receiver in front of the injection nozzle 20 every time a purging operation is performed.

By simply providing the second rotary valve runner 41b in the rotary valve 40, the molten material recovery runner 31c can be used for purging, so that the injection nozzle 20 is purposely retracted from the mold. You don't have to let me.

As described above, there is a remarkable advantage that the purging operation can be greatly simplified.

[0047]

Since the present invention is constructed as described above, it has the following effects.

It is possible to efficiently collect the molten material leaking from the rotary valve, avoid troubles such as malfunction of the rotary valve, and ensure the safety of the operator.

In addition, the efficiency of the purging operation can be greatly improved and the productivity of the metal injection molding machine can be improved.

By using such a rotary shutoff nozzle, a metal injection molding machine having high performance and high safety can be realized.

[Brief description of drawings]

1A and 1B show a rotary shutoff nozzle of a metal injection molding machine according to an embodiment, FIG. 1A is a schematic elevational view thereof, and FIG. 1B is a partial sectional view showing a part of a valve block and a rotary valve. is there.

FIG. 2 is a diagram explaining the operation of the apparatus of FIG.

3A and 3B show a conventional example, in which FIG. 3A is a schematic elevational view thereof, and FIG. 3B is a partial sectional view showing a part of a valve block and a rotary valve.

[Explanation of symbols]

10 heating cylinder 20 injection nozzles 21 Injection nozzle runway 30 valve block 30a cylindrical hole 31 valve block runway 31c Molten material recovery runner 32 recess 33 Runaway Runway 40 rotary valve 41a, 41b Rotary valve runner 42 lever 44 Linear actuator 51-55 Cartridge heater

Claims (3)

(57) [Claims] 1. An injection nozzle (20) for injecting a molten material.
A rotary valve (40) having first and second connection holes (41a, 41b), a valve block (30) having a cylindrical hole (30a) rotatably accommodating the rotary valve, A first runner (31) having a driving means (44) for rotationally driving a rotary valve, the valve block communicating with the injection nozzle, and one end opened to the cylindrical hole and the other end opened to the outside. Second runway (31
c) , wherein the rotary valve has the first rotary position in the first rotational position.
The discharge port of the heating cylinder (10) is in front by the connection hole of 1.
It is connected to the first runner and the
A second connection hole connects the discharge port of the heating cylinder.
A rotary shut-off nozzle for a metal injection molding machine, which is configured to communicate with the second runner. 2. The valve block has a recess (32) for accumulating the molten material leaking into the cylindrical hole and an escape runner (33) for guiding the molten material in the recess to the second runner. The rotary shutoff nozzle of the metal injection molding machine according to claim 1 , wherein the rotary shutoff nozzle is provided. 3. A rotary valve and the rotary shut-off nozzle according to claim 1 or 2 wherein the metal injection molding machine, characterized in that the heating means for heating the valve block (51-55) is provided.