JPH05285627A - Nozzle blocking valve for metal injection molding device - Google Patents

Abstract

PURPOSE:To prevent the leakage of material and to avoid mixing impurity caused by oxidation by forming a through-hole in a taper shape with a smaller diameter at the injector side and a larger diameter at the metallic mold side and providing a spherical shaped abutting face. CONSTITUTION:A spherical shaped valve main body 41 is rotated by a rotating mechanism and a material flow path 9 is opened/closed by changing the communicating state of the taper shaped through-hole 43. The flow path 9 is closed when the material is measured and opened when the injecting work is carried out. After the injection work is done, a formed product in a metallic mold 3 is solidified and released from the metallic mold. Since the through-hole 43 is formed to have a larger diameter at the metallic mold side, the solidified body in the through-hole is pulled out with the formed product. Immediately after the product is released from the metallic mold, the contact between molten metal in the injector 1 side and air is shut by closing the flow path 9 by rotating the valve main body 41 and an inconvenience such as oxidation is not generated. Since the through-hole 43 is tapered to have a smaller diameter toward the injector side, this structure is effective to prevent a back flow. Furthermore, a valve mechanism as this is convenient for maintenance from the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a nozzle closing valve for closing a material flow passage between a mold and an injection machine.

[0002]

2. Description of the Related Art Conventionally, an injection machine of an injection molding apparatus includes a type having a stop valve in a nozzle and a type not having a stop valve. The so-called open type, which does not have a stop valve, is often found in relatively small equipment, and leakage of material during metering or before and after injection is caused by solidification of the material at the nozzle tip due to temperature decrease, or deterioration of fluidity. It is intended to prevent and allow some leakage of material. On the other hand, in the case of a type in which a stop valve is provided in the nozzle to prevent accurate metering or leakage before and after injection, a valve mechanism is often provided in the nozzle. Injection molding equipment has been put to practical use and has a track record. In the case of a molding machine for metal casting, as the valve mechanism, a type using a piston type valve for the molten metal supply port and injection port is also known.

[0003]

However, among the above-mentioned types, the open type without the stop valve allows the device to be constructed very easily, while it does not oxidize such as magnesium alloy. When a thixomold is used to form a metal material that is easy to be used, it easily reacts with the air in the environment and is easily oxidized, leading to problems such as nozzle clogging or product quality deterioration.
Also, leakage of material was dangerous in some cases. On the other hand, in the case of the type in which the valve mechanism is provided in the nozzle, the maintainability is poor, and the durability of the valve mechanism deteriorates because of the high temperature region, and further there is the problem of material retention in the valve mechanism section. there were. And, such a problem has become a more serious problem in the case of the magnesium alloy which is easily oxidized as described above. Further, in the case of a valve mechanism in which piston type valves are used for the molten metal supply port and the molten metal injection port, the molten metal is likely to be inserted into the slide portion and the like, and there is a problem in reliability of operation and durability.

[0004]

In order to solve such a problem, the present invention relates to a nozzle closing valve for opening and closing a material flow path between an injection machine and a mold, and a rotating mechanism between the injection machine and the mold. A rotatable valve body was provided, and the valve body was provided with abutting surfaces capable of abuttingly contacting each of the tip end portion of the injection machine and the material supply inlet portion on the die side. Then, a through hole that connects the contact surface and connects the material flow path on the injection machine side and the material flow path on the mold side is provided, and the through hole is formed into a tapered shape with a small diameter on the injection machine side and a large diameter on the mold side. did. Further, the contact surface is spherical.

[0005]

The valve body is rotated by the rotating mechanism to change the communication state of the tapered through holes to open and close the material flow passage. Then, the flow path is blocked during the measurement of the material, and the flow path is opened in the injection process. When the molded product is solidified in the mold after injection, the mold is released, but the solidified body in the through hole is extracted together with the molded product. That is, since the through hole has a large diameter on the die side, it can be pulled out as it is. Immediately after that, if the valve body is rotated to close the flow path, the contact between the molten metal remaining on the injector side and the air is blocked, and there is no problem such as oxidation. Further, since the through hole is tapered toward the injection machine side, it is also effective in terms of preventing backflow. Further, the valve mechanism of such a form has good maintainability from the outside.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a nozzle closing valve of a metal injection molding apparatus of the present invention will be described with reference to the attached drawings. 1 is an overall front view of the metal injection molding apparatus of the present invention, FIG. 2 is an enlarged cross-sectional view of a nozzle closing valve, FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, in which the valve body is rotated 90 degrees. It is a figure.

First, a general outline of the metal injection molding apparatus will be described with reference to FIG.

The metal injection molding machine comprises a mold 3 connected to one end side of the injection machine 1 via a nozzle closing valve 2 and a material supply chamber 4 connected to the other end side of the injection machine 1. The ingot-shaped metal material W supplied from No. 4 is processed to form a semi-solidified slurry, which is injected into the mold 3.

The injection machine 1 is provided with a heating cylinder 7 supported by a cylinder holder 6 on a support base 5, and a screw 8 provided in the heating cylinder 7, and resistance heating is provided around the heating cylinder 7. A coil 10 and a heat insulating material 11 are provided to cover the surroundings. The inside of the heating cylinder 7 is configured as a material flow path 9, and the nozzle portion 1 as the tip of the injection machine is provided on the tip side of the heating cylinder 7.
2 is provided, and the tip end surface of the nozzle portion 12 has a curved concave shape 12a as shown in FIG.

On the other hand, the screw 8 has at least a spiral groove provided on the front side of the material supply chamber 4, and a stop valve 13 is provided at the tip of the spiral groove.
The lower end of the material supply chamber 4 faces the upper part of the rear end of the spiral groove. The rear extending portion of the screw 8 is connected to the screw rotating motor 14 and is rotatable.

The screw rotating motor 14
Is mounted on the support base 5 via a slide guide 15, and is slidable back and forth (left and right in FIG. 1).

By the way, the rear end side of the screw 8 extends further rearward from the screw rotation motor 14 via a coupling and is connected to a screw forward / backward movement cylinder unit 16. Therefore, the screw 8 and the screw rotation motor 14 both move back and forth by the operation of the cylinder unit 16 for screw forward / backward movement.

The sliding portion between the heating cylinder 7 and the screw 8 is provided with a seal portion such as a metal packing or a metal seal in an appropriate place to form a sealed structure in which the heating cylinder 7 avoids contact with the outside. There is.

Further, a ceramic plate 17 is provided at the joint between the support base 5 and the cylinder holder 6, and an appropriate place on the support base 5 side and an appropriate place on the rear part of the heating cylinder 7 are cooled by a cooling coil or the like. This is because the cylinder holder 6 is heated more than a normal injection molding machine, so that adverse effects on other devices and the like are avoided.

Next, an outline of the material supply chamber 4 will be described.

The material supply chamber 4 is divided from above into an ingot introduction chamber 21, a heating chamber 22, a greenhouse 23, and a chop chamber 24, and a first shutter 25 is provided between the introduction chamber 21 and the heating chamber 22. The second shutter 26 is provided between the heating chamber 22 and the greenhouse 23 and can be shut off. In addition, each room 21, 22, 2
Metal packings and metal seals are used at appropriate places in both 3 and 24 to form a sealed structure.

Then, the first and second shutters 25, 2
6 can be moved back and forth horizontally by the respective opening and closing cylinder units 27 and 28, and is opened and closed in the direction orthogonal to the material supply path formed in the vertical direction.

The introduction chamber 21 is a chamber for supplying the ingot W, and is constructed so that the temperature inside the chamber can be kept constant by a heater provided in the periphery thereof, and is provided with an ingot holder capable of descending toward the heating chamber 22. There is.

The heating chamber 22 is a chamber for heating the ingot W, and has a second sleeve 26 on which the ingot W is placed and a ceramic sleeve around which a heating coil is wound.

An inert atmosphere mechanism 30 is connected to the heating chamber 22 and the introduction chamber 21. The inert atmosphere mechanism 30 includes a vacuum pump 31 that evacuates the air in the room and a gas cylinder 32 that supplies an inert gas such as argon, nitrogen, and carbon dioxide into the room. It is provided to maintain good quality.

The greenhouse 23 is a chamber for preventing the temperature from lowering until the heated ingot W is chopped, and is kept at a predetermined temperature by the heater, and the height of the chamber is equal to that of other chambers. It is longer than the chamber and is considered to serve as a temporary stocking chamber for materials or a chamber for adjusting the supply amount.

The lower chop chamber 24 is a chamber for cutting and crushing the ingot W having a reduced deformation resistance and supplying it to the screw 8 in the lower heating cylinder 7, and the upper portion of the chop chamber 24 is above the chop chamber 24. , Kneader type two-axis chopper 3
3 is provided.

The biaxial chopper 33 has a pair of rotating bodies having mutually opposite spiral blades, and the rotating bodies are rotated in opposite directions to engage the spiral blades in a non-contact state to lower the ingot W downward. It is crushed so as to be drawn into. The biaxial chopper 33 rotates in synchronization with the screw 8 and also serves as a stopper for the ingot W when stopped.

The chop chamber 24 is also heated and held by a heater in order to prevent the temperature from decreasing, and the chopper 3
The hydraulic or electric motor for driving 3 is located far away from the device to avoid the adverse effect of heat.

On the other hand, the mold 3 adjacent to the nozzle closing valve 2 described later has a pair of fixed mold 34 and movable mold 35, and a material supply inlet 36 is provided at the center of the fixed mold 34. .. Then, the front surface of the material supply inlet 36 is
As shown in FIG. 2, the recessed portion 36 a has a spherical shape, and a tapered runner 37 as a material flow path provided inside communicates with a product-shaped portion 38 between the molds 34, 35. The taper of this runner 37 is
The shape is such that the side expands.

Next, the nozzle closing valve 2 will be described.

The nozzle closing valve 2 is provided on a rotary bearing 40 and comprises a valve body 41 rotatable about a vertical axis and a rotating mechanism for rotating the valve body 41. The rotating mechanism is not shown. It is driven by a motor, a cam, etc.

As shown in FIG. 2, the valve body 41 is made of, for example, a metal material or fine ceramic and has a substantially spherical shape. The valve body 41 includes the nozzle portion 12 on the injection machine 1 side and the material supply inlet portion 36 on the die 3 side. The contact surfaces 42a and 42b are provided so as to closely contact the recessed shapes 12a and 36a.

The opposing contact surfaces 42a, 42a, 4
A through hole 43 is provided that connects 2b and allows the material flow passage 9 on the injection machine 1 side and the runner 37 on the mold 3 side to communicate with each other.
The side is tapered with a large diameter. Then, by rotating around the vertical axis, the material flow path is opened and closed as shown in FIGS. 2 and 3, but such rotation need not be 90 degrees as shown in FIG. 3, and the flow path is blocked. The angle may be any angle.

A heater 44 for temperature control is wound around the valve body 41 to prevent the nozzle temperature from decreasing.
Alternatively, the temperature change of the molten metal is prevented. And the circumference is covered with the heat insulating material 46.

A pair of scrapers 45 are provided in the vicinity of the nozzle portion 12 and the material supply inlet portion 36 at the same height as the through hole 43 to scrape off the metal material adhered when the valve body 41 rotates. I am trying.

The operation of the valve closing valve 2 as described above will be described. The introduction chamber 21 by the inert atmosphere mechanism 30
When each chamber or the like is evacuated and inactivated via the heating chamber 22, an ingot W of, for example, a magnesium alloy is supplied into the introduction chamber 21 and processed.

That is, the ingot W is heated in the heating chamber 22 by the power, frequency, time, etc. set in advance by a test until it reaches the semi-solidification region, and then chopped by the biaxial chopper 33 in the chopping chamber 24. ..
In other words, the deformation resistance of the heated ingot W is reduced from about several hundredths to several thousandths, and the ingots W rotate in the reverse direction.
It is torn and crushed by the spiral blades of the two rotating bodies and cut.

The cut metal material is supplied into the spiral groove of the screw 8 in the heating cylinder 7, and the solid dendrite is divided and granulated by the strong stirring action of the screw 7 and the heating from the heating cylinder 7. It becomes a semi-solidified slurry and is carried forward.

At this time, the nozzle closing valve 2 closes the flow path as shown in FIG. 3, and the stop valve 1 in front of the screw 8 is closed.
Since No. 3 is open, the screw 8 moves backward due to the pressure of the slurry pushed forward of the screw 8. Then, a predetermined amount of slurry is stored in front of the screw 8.

Injection is carried out when a predetermined amount of slurry is stored. That is, when the stop valve 13 in front of the screw 8 is closed and the nozzle closing valve 2 is rotated at the same time to connect the material flow passage 9 of the injection machine 1 and the runner 37 on the die 3 side, the cylinder unit 16 for screw forward / backward movement. By screw 8
Is rapidly extruded to inject and fill the product shape portion 38 of the mold 3 with a metal material.

At the time of this injection, the nozzle closing valve 2 is heated by the temperature adjusting heater 44, if necessary.
In addition to smoothing the flow of material during injection, heating is stopped after the injection is completed.

Then, when it is solidified as it is,
The solidified state progresses from the product shaped portion 38 toward the runner 37 on the upstream side, and finally reaches the portion inside the through hole 43 of the nozzle closing valve 2.

Then, after opening the mold 3 at that time,
For example, when the molded body is extruded to the left in the drawing by an extruding pin (not shown) provided in the fixed mold 34, the runner 37 and the solidified body in the through hole 43 are simultaneously extracted together with the product shape portion 38.

Immediately after being drawn out, the nozzle closing valve 2
Is rotated to shut off the tip of the nozzle portion 12 to shut off the inside of the heating cylinder 7 from the outside air. Therefore, the oxidation of the metal material remaining in the material flow path 9 does not proceed, and the molding quality in the next molding shot is not deteriorated.

During the rotation of the nozzle closing valve 2, the through hole 43
The scraping off of the material adhering to the vicinity of the outlet with the scraper 45 is as described above.

Next, the type of another embodiment shown in FIG. 4 will be described.

In this apparatus, a plunger injection machine 50 is arranged between the die 60 and the nozzle closing valve 2 so that kneading slurry of the material and injection into the die are performed separately. .. The plunger injection machine 50 is provided with a plunger sleeve 52 having a ceramic sleeve 51 inside and a plunger tip 53 slidable in the plunger sleeve 52, and the circumference of the plunger sleeve 52 is covered with a heater 54 for heat retention. ing.

A heat insulating material 55 is provided around the heat retaining heater 54, and the plunger sleeve 5 is provided.
A plurality of thermocouples for temperature control are provided at predetermined positions in 2.
Further, this plunger sleeve 52 is a semi-closed sleeve without a pouring port opened to the outside unlike a so-called cold chamber sleeve. In the embodiment, the ceramic sleeve 51 is fitted on the inner surface in order to maintain heat and improve durability, but it may be coated with ceramic.

The plunger sleeve 52 is vertically oriented so that the plunger tip 53 slides up and down, and a material supply inlet portion 56 is provided on the lower side surface of the plunger sleeve 52 to form an internal tapered shape. The material flow path 57 of is open to the inside of the sleeve 52. Further, on the front surface of the material supply inlet portion 56, a spherical concave shape 56 that can come into close contact with the spherical nozzle closing valve 2 is provided.
a is formed. Although the plunger sleeve 52 is oriented vertically in the embodiment, it may be oriented horizontally.

The end of the plunger sleeve 52 has a mold 6
It is connected to 0. The mold 60 is provided with a pair of mold supporting frames 61 and 62, a fixed mold 63 held by the mold supporting frames 61 and 62, a movable mold 64, and a shunt 65, and the plunger sleeve 52 has the shunt. It communicates with the product shape part 66 between both molds 63 and 64 via the child 65. The configurations of the nozzle closing valve 2, the screw injection machine 1 and the like are the same as in the above example.

The outline of the operation of the injection molding machine configured as described above is as follows. First, the screw 8 rotates with the nozzle closing valve 2 closing the material flow passage to push the slurry forward.

When a certain amount of slurry is accumulated, the stop valve 13 in front of the screw 8 which has been open until then is closed, and at the same time, the nozzle closing valve 2 is rotated to connect the flow passages.

After that, the screw 8 advances and pushes the slurry accumulated forward into the plunger sleeve 52 in a short time, and then the flow path is blocked by the nozzle closing valve 2 and injected by the plunger tip 53. At this time, since the semi-solidified slurry is still contained in the through hole 43 of the nozzle closing valve 2, the internal slurry does not leak to the outside during rotation.
For example, means such as providing a cover member made of ceramic or the like that can close the respective end portions of the through holes 43 along the rotation direction is taken. Further, at this time, at the same time, the temperature adjusting heater 44 is always heated so as not to solidify the internal slurry.

When the screw injection machine 1 is injected with the flow path blocked by such a method, even if the mold is opened for taking out the product after solidification, the metal material on the upstream side of the nozzle closing valve 2 is air. Oxidation can be effectively prevented without contacting with. Further, since the plunger sleeve 52 is also a semi-closed sleeve that does not come into contact with the outside world as described above, the effect of preventing oxidation is high.

Further, by carrying out the kneading and the injection of the materials by the separate devices in this way, it becomes extremely easy to set the temperature control and the time control at the time of the kneading and the injection at the optimum conditions, respectively. It can contribute to the improvement of molding quality. Moreover, since the pressure at the time of injection does not affect the screw 8 side, strict performance is not required for the structural materials such as the heating cylinder 7 and the screw 8, and it is necessary when the screw 8 performs kneading and injection at the same time. Since it is not necessary to move the screw 8 and the rotation motor 14 at the same time at high speed, it is possible to provide an energy-saving type compact device.

[0052]

As described above, the nozzle closing valve of the present invention is
Since it is rotatably arranged between the injection machine and the mold, and the communication of the material flow path is blocked or opened by the tapered through hole, not only the material leakage can be prevented but also the outside air can be prevented. It is possible to reliably block the material and avoid mixing of impurities due to oxidation. Therefore, the quality of the molded product can be improved. Also, the structure is simple, and it is not always in a high temperature state as in the case where it is installed in the nozzle, and since it can be easily maintained from the outside, maintainability, durability, reliability, etc. It is superior to the conventional valve structure.

[Brief description of drawings]

FIG. 1 is an overall front view of a metal injection molding apparatus of the present invention.

FIG. 2 is an enlarged sectional view of a nozzle closing valve.

FIG. 3 is a cross-sectional view taken along the line AA in FIG.
Rotated state diagram

FIG. 4 is a partial view of an injection molding apparatus according to another embodiment.

[Explanation of symbols]

 1 Injection Machine 2 Nozzle Closure Valve 3 Mold 9 Material Flow Path 36 Material Supply Inlet 37 Runner 41 Valve Main Body 42a, 42b Abutment Surface 43 Through Hole W Ingot

Claims (1)

[Claims] 1. A nozzle closing valve for opening and closing a material flow path between an injection machine and a mold, wherein the nozzle closing valve includes a valve main body provided between the injection machine and the mold, and the valve main body. The valve body is provided with a rotation mechanism for rotating about a rotation axis,
A contact surface capable of closely contacting each other is provided at each of the tip end portion of the injector and the material supply inlet portion on the die side, and the contact surface is connected and the material flow path on the injector side and the die side. A through hole that connects the material flow paths to each other is formed, the through hole is formed in a tapered shape with a small diameter on the injection machine side and a large diameter on the mold side, and the contact surface is formed into a spherical shape. Nozzle closing valve for injection molding equipment.