JPH05161951A - Die casting apparatus - Google Patents

Abstract

PURPOSE:To prevent the spill of molten metal during the molten metal supplying by closing an open/shut valve after a prescribed quantity of the molten metal is supplied into a pouring hole or a feeding passage in a die, immediately ascending an injection plunger and injecting the molten metal into a cavity. CONSTITUTION:A suction hole 30 is closed with a valve rod 31, and in the opening condition of the open/shut valve 14 while a valve body 16 is retreated, by descending a piston 26, the molten metal M in a cylnder barrel 27 is poured into a pouring sleeve 9 through a passage 33, check valve 34, conduits 22, 20, feeding passage 13, runner part 7 and the pouring hole 6. Then, the injection plunger 11 is beforehand ascended to the upper limit and by slowly descending the plunger according to the pouring of the molten metal M, rapid fluidity and spattering of the molten metal are suppressed as less as possible, and entrapment of the air and temp. drop of the molten metal can be prevented. Further, as the molten metal is not brought into contact with the air, even in the case of the molten metal easily oxidized, the casting can be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting machine, and more particularly to a die casting machine having an improved hot water supply mechanism suitable for magnesium alloy die casting.

[0002]

2. Description of the Related Art Conventionally, a casting cavity communicated with a casting sleeve through a casting opening at a lower part of a mold with which a casting sleeve is engaged and a hot water supply passage (runner portion) extending in the vertical direction. In order to perform casting by a die casting apparatus equipped with a die device having a mold and a hot water supply device for supplying hot water into the casting sleeve, the molten metal is put into the casting sleeve and the casting sleeve is placed at the bottom of the mold. The injection plunger is raised, and then the molten metal in the casting sleeve is fed into the cavity for injection.

As a method of pouring the molten metal into the casting sleeve, the casting sleeve is separated from the mold and poured by a ladle. In order to make it easier to pour the molten metal with the ladle, the casting sleeve may be tilted (for example, Japanese Patent Publication No. 57-21414, FIG. 3), or the casting sleeve may be retracted from the bottom of the mold while keeping the casting sleeve in the vertical position (the same issue). (Fig. 4) In Fig. 2 of the same issue, a method of lowering the lower mold with the casting sleeve attached to the lower mold, and pouring the molten metal into the casting sleeve from above the lower mold through the hot water supply passage from the ladle It is shown.

[0004]

In the method in which the casting sleeve is separated from the mold and the molten metal is poured by the ladle, the time from the pouring of the molten metal into the casting sleeve to the actual injection into the cavity is increased. become longer. In addition, foreign substances are easily mixed in the molten metal. Further, when the casting sleeve is tilted, the molten metal cannot be filled to the upper edge of the casting sleeve, so that the casting sleeve needs to be lengthened accordingly. Even in the method of pouring the molten metal from above the lower mold while the lower mold and the casting sleeve are attached to each other, it is necessary to wait only while the upper mold and the lower mold are clamped, and the injection time is long. Become. Further, there is a problem that the spilled molten metal is easily splashed on the upper surface of the lower mold.

Further, in any of the above methods, the molten metal is exposed to the atmosphere when it is transferred to the pouring sleeve or until the pouring sleeve is engaged with the pouring port. For this reason, the molten metal is easily oxidized and is not suitable for casting easily oxidizable metals (eg magnesium, aluminum and its alloys), and there is a possibility that casting defects may occur due to the inclusion of oxides.

[0006]

A die casting apparatus of the present invention has a movable die having a casting cavity formed on a mating surface and a fixed die, and a die lower part to which a casting sleeve is engaged. A mold casting device comprising a mold device communicating with the casting cavity through a casting opening and a hot water supply passage extending in the vertical direction, and a hot water supply device for supplying hot water into the casting sleeve. A horizontal hot water supply passage which is provided in a fixed type and is opened on the inner wall surface of the pouring port or the hot water supply passage; and a conduit which communicates the rear lower surface of the hot water supply passage with the hot water supply device. , A heater for heating molten metal provided in the conduit,
Of the hot water supply passage, a valve seat provided in the vicinity of the pouring port or the hot water supply passage in the shape of a taper that expands toward the movable mold, and the movable die holds the valve seat. And a valve element of an on-off valve for opening and closing the hot water supply passage that is advanced and retracted in the seating direction with respect to the valve seat.

[0007]

In the die casting apparatus of the present invention, the casting sleeve is attached to the casting opening of the clamped die,
The on-off valve is opened, and the molten metal is supplied from the water heater to the pouring port in the mold or the hot water supply passage. This molten metal is stored in the casting sleeve. After supplying the required amount of molten metal, close the on-off valve,
Immediately raise the injection plunger and inject the molten metal into the cavity. As described above, in the die casting apparatus of the present invention, when the molten metal is supplied into the casting sleeve, it can be immediately injected.
Moreover, the molten metal does not spill during hot water supply. Further, the casting sleeve can be always in a vertical position, a large amount of molten metal can be poured into the casting sleeve, and the length of the casting sleeve can be short.

In the die casting apparatus of the present invention, the molten metal is not exposed to the atmosphere until it is injected into the cavity from the hot water supply apparatus. Therefore, it is suitable for casting a metal that is easily oxidized, and also prevents casting defects due to the oxide. It is extremely useful for die casting of magnesium alloys that are easily exposed to the atmosphere and explode. Since the conduit is provided with a heater, the molten metal remaining in this conduit does not solidify and can be directly used for the next hot water supply. Therefore, the pouring time can be made very short.

In the die casting apparatus of the present invention, the hot water supply passage is opened and closed by the valve body held by the movable die seated on or away from the valve seat provided on the fixed die. In this case, the fixed type does not require a slide holding member for slidably supporting the valve body, and the sliding surface of the slide holding member does not face the hot water supply passage. As a result, the sealing ability of the hot water supply passage is improved.

The applicant of the present invention has proposed a casting apparatus similar to the present invention in Japanese Patent Application No. 3-9945. However, in the casting apparatus of this prior application, the valve body is inserted into the molten metal passage from the side opposite to the fixed cavity so that the molten metal can be continuously supplied from the molten metal passage. In such a casting apparatus of the prior application, the sliding surface between the valve body and the fixed mold faces the molten metal passage, so that the molten metal may leak from the sliding surface. The present invention has been improved so as to reliably prevent such leakage of molten metal.

[0011]

Embodiments Embodiments will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a mold casting apparatus according to an embodiment of the present invention, and FIG. 2 and subsequent drawings are enlarged cross-sectional views near a hot water supply passage and an on-off valve. The mold device 1 includes a fixed mold 3 attached to a fixed platen 2.
And a movable die 5 attached to a movable platen 4 which is moved forward and backward with respect to the fixed die 3 by a toggle mechanism (not shown) or the like. This fixed mold 3
A casting port 6 is provided on the bottom surface of the movable die 5 to enable the molten metal to be supplied to the cavity 8 via a runner portion 7 serving as a hot water supply passage. The upper end of the casting sleeve 9 can be engaged with the casting port 6. The casting sleeve 9 is provided at the upper end portion of the injection device 10, and the injection plunger 11 is slidably arranged in the casting sleeve 9. The injection plunger 11 is connected to an injection cylinder (not shown) via a rod 12 and is vertically moved by the injection cylinder. After the casting sleeve 9 is slightly lowered from the state shown in FIG. 1 and separated from the molds 2 and 3, and is rocked laterally or moved horizontally to move the opening to a position away from the mold position. The inside of the injection sleeve 9 can be cleaned by spraying or a lubricant can be applied.

From the opening of the inner peripheral wall surface of the runner portion 7 to the casting port 6
The casting port 6 and the outside of the mold are
They are communicated with each other through a horizontal hot water supply passage 13 provided in the fixed mold 3. However, the inner peripheral surface of the hot water supply passage 13 provided in a horizontal state has a taper shape that gradually expands toward the movable mold 5 side, and all the molten metal in the hot water supply passage 13 is on the pouring port 6 side. It is designed to run down. The opening / closing valve 1 is provided in the hot water supply passage 13 near the casting port 6.
4 are provided. The on-off valve 14 includes a tapered valve seat 15 that expands toward the movable mold 5 and a valve body 16 that is held in the movable mold 5 so as to be movable back and forth and can be seated on the valve seat 15. I have it. The valve body 16 has an open / close cylinder (valve body drive device) 1 fixed to a part of the movable mold 5.
The piston rod 18 of No. 7 is connected by screwing. Reference numeral 19 is a guide bush for sliding the valve body. In addition,
A solenoid or the like may be used instead of the cylinder.

The hot water supply passage 13 also serves as a molten metal reservoir, and a conduit 20 inclined obliquely rearward is attached to the lower rear surface of the horizontal hot water supply passage 13. Conduit 2
0 is an inner liner 21 made of ceramic or heat-resistant metal (for example, SKD61) in contact with the molten metal, and an induction heating coil (induction heater) 21a and a heat insulating material 21b are provided on the outer peripheral side of the inner liner 21. .. An inner liner made of ceramic or heat-resistant metal or an induction heating coil may be used around the hot water supply passage 13 in the fixed mold 3.

A hot water supply device 23 is installed through a horizontal conduit 22 provided following a slanted conduit 20 for supplying hot water to the hot water supply passage 13. This water heater 2
3 includes a molten metal storage tank 24 and a pump device 25 for pumping the molten metal in the storage tank 24. This pump device 25
Is a cylinder barrel 27 in which the piston 26 is inserted,
A cylinder 28 for moving the piston 26 up and down is provided, and the inside of the cylinder barrel 27 is communicated with the inside of the storage tank 24 through the passage 29 and the suction port 30. A valve rod 31 is provided to open and close the suction port 30, and the valve rod 31 is moved up and down by a valve cylinder 32. Barrel 27
The molten metal in the inside can be sent to the conduit 22 via a passage 33 and a check valve 34. 35 is the conduit 22
Is a heater provided in the.

In the fixed mold 3, a rod 36 is slidably provided on the stationary platen 2 side of the hot water supply passage 13 in a horizontal state. Reference numeral 37 denotes a cylinder fixed to a part of the stationary platen 2, and the rod 36 can be moved in and out of the hot water supply passage 13 and retracted by the operation of the cylinder 37. In addition, a passage 38 as shown in FIG. 1 is provided in the rod 36, and a rear portion of the passage 38 is connected to a not-shown inert gas supply source such as oxygen via a connecting member 39. The front of the passage 38 is opened to the outer peripheral surface near the tip of the rod 36, and when the rod 36 advances to the hot water supply passage 13 part, the hot water supply is tapered from the opening of the passage 38 toward the end. Oxygen can be supplied into the cavity 8 through a narrow passage between the inner peripheral surface of the passage 13. A passage 46 communicating with the outside air is provided on the sliding surface of the rod 36 behind the hot water supply passage 13 of the fixed mold 3, and when the rod 36 retracts, the hot water supply passage 13 passes through the passage 46 to the outside air. It is supposed to be understood.

Reference numeral 40 is a feeder pin, and the pin 40 is moved forward and backward by a cylinder 41 attached to a part of the fixed mold 3. 42 is a product extruding device including an extruding pin 43. 44 is a known mold degassing device,
It communicates with the cavity 8 through a gas vent passage 45 provided on the separation surface of the molds 3, 5.

In the die casting machine thus constructed, when the valve rod 31 is raised and the piston 26 is raised in this state, the molten metal M in the storage tank 24 is transferred to the cylinder barrel 27.
Is sucked in. At this time, since the check valve 34 is provided in the passage 33 and the conduit 22 part, the molten metal M in the conduits 20 and 22 is
Will not flow back and be sucked into the cylinder barrel 27. Next, with the valve body 16, the feeder pin 40, and the extrusion pin 43 for extruding the product retracted to predetermined positions, the mold is clamped as shown in FIG. In a state of being docked on the lower surfaces of the molds 3 and 5, the cylinder 37 is operated to advance the rod 36 in FIG. 1 until the outlet of the passage 38 in the rod 36 faces the tapered inner peripheral surface of the hot water supply passage 13. It is moved and an on-off valve (not shown) is operated to introduce an inert gas such as oxygen gas from the outlet of the passage 38 to expel the air in the cavity 8 and the casting sleeve 9 to fill it with oxygen.

Next, the suction port 30 is closed by the valve rod 31, and as shown in FIG. 2, the piston 26 is lowered while the open / close valve 14 with the valve body 16 retracted is still open. And the molten metal M in the cylinder barrel 27
Is poured into the casting sleeve 9 through the passage 33, the check valve 34, the conduits 22 and 20, the hot water supply passage 13, the runner portion 7 and the casting port 6. In addition, the injection plunger 11
It is preferable to raise the temperature up to the ascending eye and gradually lower the temperature as the molten metal M is poured, in order to prevent the extreme flow and scattering of the molten metal as much as possible, and prevent the entrainment of air and the temperature decrease of the molten metal. At this time, the casting sleeve 9 is filled with oxygen, but as the molten metal drops and is supplied into the casting sleeve 9, the oxygen in the casting sleeve 9 is driven away toward the upper cavity 8 direction. And escapes from the open mold degassing device 44. In addition, the pump device 25
Is stopped, all the melt M in the hot water supply passage 13 whose inner surface is slightly tapered falls into the casting sleeve 9,
The molten metal in the conduit 20 remains filled up to the top of the conduit 20. Then, the next pouring can be performed efficiently in a shorter time.

After a sufficient amount of molten metal M is stored in the casting sleeve 9, the operation of the pump device 5 is stopped. Since the inner peripheral surface of the hot water supply passage 13 is inclined toward the runner portion 7, all the molten metal in the hot water supply passage 13 is poured into the casting sleeve 9.
Enter inside. The molten metal in the conduit 20 remains with the upper end surface entering. Next, as shown in FIG. 4, the valve body 16 is seated on the valve seal 15 to close the opening / closing valve 14, and the rod 36 is retracted to the position shown in FIG. 4 to raise the injection plunger 11. , The molten metal M is injected into the cavity 8. At this time, the cavity 8 is filled with oxygen, but due to the casting of the molten metal M into the cavity 8, the oxygen in the cavity 8 is discharged to the atmosphere via the gas vent passage 45 and the mold degasser 44. To be done. Of course, when the molten metal reaches the mold degassing device 44, the valve of the mold degassing device 44 is closed by the inertial force of the molten metal or an electric command, and the molten metal enters or leaves the mold degassing device 44. It doesn't blow out. Further, since there is no air in the cavity 8 but only oxygen, even if a small amount of oxygen not discharged outside during casting remains in the molten metal, the oxygen reacts due to high heat and disappears, and oxygen remains. Since the open space is crushed by the high-pressure molten metal, no cavities are generated in the molten metal and thus in the cast product. In this embodiment, since the on-off valve 14 is provided, the injection pressure reliably prevents the molten metal M from flowing backward toward the hot water supply passage 13 and the storage tank 24. Further, since the rod 36 is retracted so that the passage 46 communicates with the hot water supply passage 13, in the unlikely event of high pressure casting,
If for some reason the on-off valve 14 is not completely closed and there is a slight gap, such as when a small burr adheres to the on-off valve 14 that should have been completely closed, if there is a slight gap, Part blows out into the hot water supply passage 13, but even in that case,
The force exerted on the gas by the molten metal or the molten metal blowing out is the path 46
The molten metal remaining in the conduit 20 is not adversely affected because it is released to the outside through the pipe.

At the time of injection, the cylinder 41 is operated in a state where the molten metal M is substantially filled in the cavity 8 and the pin 40 for feeding is advanced to perform a feeding action. When the injection finishes and the molten metal in the cavity 7 solidifies and cools for a predetermined time, the mold is opened. At that time, the cylinder 37 is operated to move the rod 36 forward at the same time, and after covering the upper end portion of the conduit 20 with the rod 36, oxygen or air or a lubricant is sprayed from the passage 38 into the hot water supply passage 13, and the hot water supply passage 1
Clean inside 3. This state is shown in FIG. After that, after the product is taken out, the mold is clamped again, and the molten metal is supplied into the casting sleeve 9 by the same procedure as described above, and casting is performed. In this case, the molten metal remaining in the conduits 20, 22 and the like is maintained at the required temperature by the induction heating coil 21a, the heater 35, etc., and is immediately supplied into the pouring port 6 by the pump pressure. The supply is extremely quick.

After pouring the molten metal M into the casting sleeve 9, the on-off valve 14 can be closed and the injection process can be started immediately. Therefore, it is possible to shorten the casting time, and it is surely prevented that the temperature of the molten metal in the casting sleeve 9 is lowered or partially solidified, so that the casting with high quality is achieved. You can get the product.

Further, as is clear from the figure, the storage tank 24
The molten metal in the casting sleeve 9 is completely exposed to the atmosphere.
Since it is supplied inside, it is possible to cast molten metal such as aluminum and magnesium that is easily oxidized without causing any oxidation. Therefore, it is possible to cast a metal that is easily oxidized without any trouble, and it is possible to surely prevent the generation of casting defects due to the oxide, and it is possible to obtain a cast product of extremely high quality.

In this embodiment, a cooling mechanism such as water cooling can be incorporated in the valve body 16. Thereby, the valve body 16 can be protected from high heat. As you can see from the figure,
In the present embodiment, the inner peripheral surface of the hot water supply passage 13 is tapered so as to expand. Therefore, there is no portion such as a weir that obstructs the flow of the molten metal, the molten metal flows smoothly in the hot water supply passage 13, and the molten metal does not remain in this portion.

In the above embodiment, the horizontal mold clamping vertical die mold device in which the movable mold 5 is clamped from the lateral direction to the fixed mold 3 and is cast from below is shown. In this case, After the molten metal in the cavity 8 is solidified, the movable mold 5 is fixed to the fixed mold 3
When the solidified product is removed from the casting product, the biscuit portion on the casting port 6 side of the on-off valve 14 can also be taken out together with the casting product. As is clear from the figure, since the casting sleeve 9 of this embodiment is in the vertical posture connected to the casting port 6 during casting, a large amount of molten metal M can be poured into the casting sleeve 9 and the casting can be performed. The length of the sleeve 9 is also short and sufficient. It is also possible to clean the inside of the casting sleeve 9 by slightly lowering the casting sleeve 9 apart from the molds 3 and 5 and tilting it around the lower part of the injection device 10 except during casting. In the present invention, the mold may be a vertical mold clamping mold in which the movable mold is moved back and forth in the vertical direction.

[0025]

As described above, in the mold casting apparatus of the present invention, since the molten metal in the hot water supply device is supplied to the casting sleeve through the conduit, the hot water supply passage and the casting port in the mold, No molten metal spills during hot water supply. Furthermore, since the molten metal does not come into contact with the atmosphere when pouring, it is possible to cast even a molten metal that is extremely easily oxidized, such as magnesium,
Casting defects due to the formation of cavities due to oxides can also be prevented. By using the non-porous die casting method in which the casting is performed in an atmosphere of an inert gas such as oxygen, it is possible to easily and easily obtain a good quality cast product with no cavities. In addition, the pouring time is extremely short and the casting cycle can be shortened.
The temperature of the molten metal to be cast is sufficiently high, which also makes it possible to obtain high-quality cast products.

According to the present invention, the hot water supply passage provided in the fixed mold has a good sealing property, and the leak of the molten metal from the hot water supply passage is surely prevented. In the present invention, the casting sleeve can always be in a vertical posture, and a large amount of molten metal can be poured into the casting sleeve to shorten the length of the casting sleeve. If a check valve is provided at the conduit connection part of the hot water supply device, the reverse flow of the molten metal can be reliably prevented. Since the molten metal remaining in the conduit is heated by the heater provided in the conduit and maintained at the required temperature, it can be used as it is for the next pouring.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a mold casting apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state during pouring of an embodiment of the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a vertical cross-sectional view showing a state at the time of injection of the embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing a state when the mold is opened according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold device 3 Fixed mold 5 Movable mold 6 Casting port 7 Runner part 8 Cavity 9 Casting sleeve 11 Injection plunger 13 Hot water supply passage 14 Open / close valve 15 Valve seat 16 Valve body 17 Open / close cylinder 20, 22 Conduit 23 Hot water supply device 25 Pump Device 26 Piston 30 Suction Port 34 Check Valve 35 Heater 36 Rod 37 Cylinder 38 Passage 45 Mold Venting Device

Claims (1)

[Claims] 1. A casting opening at a lower portion of a die having a movable die having a casting cavity formed on a mating surface and a fixed die, the casting sleeve being engaged with the casting die, and a hot water feeding passage extending in the vertical direction. In a mold casting device comprising a mold device communicating with the casting cavity through a mold and a hot water supply device for supplying hot water into the casting sleeve, the mold casting device is provided in the fixed mold, and the casting port is provided. Alternatively, a horizontal hot water supply passage opened to the inner wall surface of the hot water supply passage, a conduit communicating the lower rear surface of the hot water supply passage with the hot water supply device, and a heater for heating molten metal provided in the conduit. , A taper-shaped valve seat that opens toward the movable mold in the vicinity of the pouring port or the hot water supply passage in the hot water supply passage, and the movable seat holds the valve seat. Opening / closing for opening / closing hot water supply passage that moves back and forth in the seating direction with respect to the valve seat A die casting machine comprising a valve body of a valve.