JP6131147B2 - Die-cast sleeve molten metal feeder - Google Patents

Description

  The present invention relates to a molten metal supply device for supplying a molten metal such as molten aluminum to a sleeve of a die casting machine, and in particular, the pressure of the die casting sleeve is reduced and replaced with an inert gas to prevent oxidation of the molten metal, and the die casting sleeve is used as it is. The molten metal supply device that pumps up molten metal and supplies molten metal to the vacuum die casting sleeve incorporates a bellows thermal expansion and shock absorbing mechanism and a corrosion-resistant ceramic tube, and decompresses the inside of the die casting sleeve and electromagnetic pump duct. In addition, the present invention relates to an electromagnetic pump structure that can hold molten metal that runs up in the duct once in the duct by the braking force of the electromagnetic pump, and a molten metal supply device that uses intermittent hot water supply with reduced braking force and accuracy. .

  For example, when an aluminum casting is produced by an aluminum die casting apparatus, an aluminum ingot is put into a molten metal tank as a melting furnace and melted, and then mechanical hot water supply means, pneumatic hot water supply means, electromagnetic induction hot water supply means, etc. The mold cavity of the die casting machine is filled with molten metal to cast an aluminum casting.

  In a die casting machine, as a pre-stage of filling a mold with molten metal, a predetermined amount of molten metal is once filled in a cylindrical sleeve and is then pushed into the mold with a plunger, so that it is predetermined in the mold. A supply system for supplying a certain amount of molten metal is used. In this case, as a means for supplying molten metal to the sleeve, an induction electromagnetic pump is often used as described in, for example, Japanese Patent Application Laid-Open Nos. 05-177329, 2001-18053, and 2004-154825. Has been. In addition to the electromagnetic pump, in Japanese Patent Laid-Open No. 05-177329, a pneumatic device provided on the molten metal tank side is used in combination as molten metal supply means. Although no prior literature is cited here, the pressure reducing device provided on the molten metal tank side may be used instead of or in combination with a pressure reducing device connected to the mold side for vacuum suction.

As described above, in a conventional molten metal supply device to a sleeve of a die casting machine, an electromagnetic pump is used as a molten metal supply means to the sleeve, and a pressurization device and a decompression device are used in combination. In these molten metal supply means, the supply and stop of molten metal is controlled by driving or stopping the induction electromagnetic pump, thereby supplying a certain amount of molten metal to the sleeve through a pipe attached to the outlet of the nozzle of the electromagnetic pump. It is planned to do.

  In any die-casting machine, a predetermined amount of molten metal is once filled in a cylindrical sleeve, and a certain amount of molten metal is filled into the mold by pushing it into the mold with a plunger. Casting, volume casting. Therefore, it is necessary to feed a predetermined amount of molten metal, which is predetermined for each hot water supply operation, to the sleeve.

At present, vacuum die casting that connects stalk between the die casting machine and the molten metal tank, depressurizes the cavities of the sleeve and mold, sucks the molten metal in the molten metal tank and casts it is already on the market, German manufacturer's baculal method is famous. In vacuum die casting, when the mold cavity and sleeve are set to -1.0 kg / cm ² G in high vacuum, the molten aluminum with a specific gravity of 2.5 g / cm ³ rises by 4 m. Unless measures are taken such that the pressure rises only about 1 m, a stalk having a height of 4 m is required between the sleeve and the molten metal tank.

As a method that does not require such a closed furnace, an electromagnetic pump is used as a brake and a direct connection between a sleeve of a die casting machine and a holding furnace has been proposed.
In a conventional apparatus for supplying molten metal to a sleeve of a vacuum die casting machine, an electromagnetic pump is used as a means for supplying molten metal to the sleeve, and a pressurizing device and a decompressing device are used in combination on the mold side. In these molten metal supply means, the supply and stop of molten metal is controlled by driving or stopping the induction electromagnetic pump, thereby supplying a certain amount of molten metal to the sleeve through a pipe attached to the outlet of the nozzle of the electromagnetic pump. It is planned to do. Based on this, the molten metal can be supplied to the sleeve without being oxidized, and a cast product which does not contain oxide or gas can be produced.

Generally, an electromagnetic pump generates a moving magnetic field in the axial direction of a duct, and an induced current is induced in the molten metal by passing the moving magnetic field through the molten metal in the duct. A thrust is induced in the direction of the moving magnetic field due to the interaction, and the molten metal is driven or braked by this thrust.

When the nozzle of the electromagnetic pump and the sleeve of the die-casting machine are directly connected via a sealed pipe, the pressure inside the mold and the inside of the sleeve are reduced by the pressure reducing device with the pressure reducing device attached to the mold side. In order to prevent the molten metal from rising up from the molten metal tank of the molten metal to which the electromagnetic pump is attached to the inside of the duct of the electromagnetic pump, the electromagnetic pump is applied with a reverse electromagnetic force to brake the molten metal. Must be put. The molten metal braked in the duct of the electromagnetic pump is supplied with a fixed amount of molten metal in the sleeve by weakening the braking force of the electromagnetic pump, and the molten metal supplied in a fixed amount is fed into the mold by the plunger in the sleeve. It is possible to make a casting that does not contain oxides or gases by injecting molten metal.

Since the electromagnetic pump generates thrust only when molten metal is present in the duct, the decompressor operates even if a moving magnetic field is generated in the direction opposite to the direction of supplying molten metal to the electromagnetic pump in advance. As the molten metal is sucked up into the duct, the braking force is applied, so the moving molten metal in the duct cannot immediately brake the molten metal that is moving. Therefore, it is necessary to generate a moving magnetic field in the direction opposite to the direction in which the molten metal is supplied to the electromagnetic pump in advance and slowly vacuum it, or use a molten metal that can be sucked up with the output of the electromagnetic pump sufficiently exceeding the pressure difference from the atmosphere. There is no choice but to brake. However, the method of slowly vacuuming takes several tens of seconds, and in the case of a die casting machine with a casting cycle of about 1 minute, the cost increases, so the latter, which can be braked for a short time, is excellent.

  As mentioned above, inductive electromagnetic pumps that use a decompression device and have no molten metal in the duct, generate a magnetic field with a magnetic flux density that can generate an output that sufficiently exceeds the pressure difference with the atmosphere downward. Using an annular flow type electromagnetic pump that can quickly brake the molten metal with the braking force generated in the molten metal while the molten metal is rising in the duct, and the nozzle that is the outlet of the electromagnetic pump runs out of hot water. In order to improve the flow rate, the nozzle tip that is installed obliquely along with the duct is cut vertically and sharply in the direction of gravity. The molten metal returning to the electromagnetic pump duct side and the molten metal falling to the die cast sleeve side are separated and the hot water is cut off. In such a device that accurately supplies the molten metal to the sleeve, the sealed metal duct that connects the tip of the electromagnetic pump nozzle to the die casting sleeve vibrates violently due to the movement of the plunger, It will vibrate. The vibration of the sealed metal duct loosens all the packings of the electromagnetic pump duct and impairs the hermeticity of the packing. Therefore, in order to suppress the vibration of the sealed metal duct, a metal bellows must be provided in the middle of the sealed metal duct to absorb the vibration and prevent the electromagnetic pump packing from being damaged by excessive vibration. In general, since metal is gradually corroded by molten metal, ceramic coating is applied to the inner surface of the sealed metal duct so that the metal duct is not corroded by the molten metal. However, even when a ceramic coating was applied to the inner surface of a closed metal duct, the ceramic coating gradually peeled off due to the difference in thermal expansion between the metal and the ceramic coating, and was corroded by the molten metal.

JP 05-177329 A JP 2001-18053 A JP 2004-154825 A

  In view of the problems in the conventional molten metal supply device described above, the present invention provides a molten metal supply device to a die-cast sleeve that uses a decompression means such as a vacuum pump and a vacuum tank and a molten metal electromagnetic pump such as an annular linear induction electromagnetic pump. Realizes accurate, rapid, and impurity-free molten metal supply control, and does not transmit excessive force due to vibration, impact, and thermal expansion from the die casting machine to the hot water supply device, but with molten metal that supplies hot water from the electromagnetic pump nozzle to the die casting sleeve. An object is to realize a molten metal supply device that does not corrode a sealed metal duct.

In the present invention, in order to achieve the object of braking the molten metal in the duct at the time of decompression, a vibration absorbing function having a buffering function by a bellows is provided between the hot water supply side metal duct 1 "for supplying the molten metal and the die casting sleeve 27 . The hot water supply side duct 1 ″ connected to the sleeve 27 is provided with a top portion 6 in which the duct gradient changes from rising to falling in the hot water supply direction of the molten metal 12. Further, a ceramic inner pipe 61 is built in a downward slope portion on the sleeve 27 side from the top of the hot water supply side duct 1 ″, and the thermal expansion of the metal duct 1 ″ is between the ceramic inner pipe 61 and the metal duct 1 ″. In order to prevent thermal stress from being applied, a gap is provided. More specifically, a hot water supply side metal duct 1 ″ which is a sealed metal pipe connecting the pump side duct 1, the intermediate duct 1 ′ of the electromagnetic pump and the die casting sleeve 27 ”. The ceramic inner pipe 61 is built in so as not to corrode, and a ceramic belt-shaped cushioning material 60 is inserted between the downward slope portion of the hot water supply side duct 1 ″ and the ceramic inner pipe 61. On the other hand, the molten metal is introduced from the top portion 6. A nozzle pipe 45 is built in the upward slope portion of the hot water supply side duct 1 ″ on the tank 11 side. Further, at the top of the hot water supply side duct 1 ″, the tip of the nozzle tube 45 is formed by making a taper hole 63 in the ceramic inner tube 61 in the hot water supply side metal duct 1 ″, which is a sealed metal pipe, and cutting the hole vertically and sharply. The taper packing 59 is fitted so that the soot generated at the tip of the nozzle pipe 45 cut vertically and sharply at the joint is not transmitted to the hot water supply side metal duct 1 ″ side which is a sealed metal pipe, Hot water supply with a built-in ceramic inner tube 61 having a structure in which the mouthpiece 62 is inserted into the nozzle tube 45 so that the taper packing 59 does not slide down, and the mouthpiece 62 is maintained without slipping off at the level difference of the nozzle tube 45. This is the side metal duct 1 ″. As a result, all the flow paths up to the intermediate duct 1 ′ and the die casting sleeve 27 are made into ceramic ducts that are corrosion resistant to the molten metal, and the molten metal is added to the sleeve 27 of the die casting machine by using both the decompression means and the molten metal electromagnetic pump. 12 is supplied. Then, an annular linear induction electromagnetic pump type molten metal electromagnetic pump having a channel gap in which the molten metal surface vibration is likely to stop at the time of suction under reduced pressure, and a predetermined amount of molten metal 12 is supplied before the molten metal 12 is supplied to the sleeve 27. Always energize the pump's electromagnetic coil to generate thrust in the reverse direction that stops atmospheric pressure.

More specifically, a nozzle tube 45 whose tip is cut vertically to cut hot water is provided in the hot water supply side metal duct 1 ", and a tapered hole 63 is formed by opening a taper hole 63 in the ceramic inner tube 61 opened at both ends. A taper packing 59 is fitted into the hole 63 so that the mouthpiece 62 is inserted into a slightly narrowed step portion of the nozzle tube 45 so that the taper packing 59 does not slide down, and further, the ceramic inner tube 61 is not rattled. Cushioning material 60 made of ceramic fiber is wound around a ceramic inner pipe 61, and the circumference thereof is covered with a metal duct 1 ″, and a hot water supply side metal is formed by a slight gap formed between the metal duct 1 ″ and the ceramic inner pipe 61. Hot water supply side metal duct so that the thermal expansion of the duct 1 ″ and the thermal expansion of the ceramic inner tube 61 extend independently in all directions. To "and excessive thermal stress on the ceramic inner tube 61 is not hot water supply side metal duct 1 generation". Further, a bellows 52 is attached between the hot water supply side metal duct 1 "and the sleeve opening so as to absorb the elongation of the hot water supply side metal duct 1" having a large thermal expansion and the vibration of the sleeve. The length of the ceramic inner tube 61 in the hot water supply side metal duct 1 ″ reaches the sleeve opening of the die casting machine so that the molten metal 12 can be supplied without contacting the metal duct 1 ″. Accordingly, the nozzle pipe 45 and the ceramic inner pipe 61, which are ceramic members, are stretched without restriction in the hot water supply side metal duct 1 ", so that excessive thermal stress is not applied to the ceramic members and the molten metal is highly corrosive. 12 can pass through the ceramic inner tube 61, which is a corrosion-resistant member, and can be supplied to the sleeve 27. To further explain, a tapered hole 63, which is an insertion port of the ceramic inner tube 61 inserted into the nozzle tube 45, is ceramic. The taper is tapered so as to taper toward the inside of the inner tube 61, and the taper packing 59 is inserted into this insertion portion so that the taper packing 59 does not protrude into the ceramic inner tube 61. In order to prevent the nozzle tube 45 from slipping down, the insertion portion of the nozzle tube 45 is slightly narrowed and a step is attached to the nozzle tube 45, When the mouthpiece 62 is inserted into the nozzle tube 45 having a reduced thickness, the taper packing 59 is fitted into the insertion portion of the taper packing 59, the nozzle tube 45, and the ceramic inner tube 61 without any gaps, and the nozzle tube 45 is hot. So that molten metal does not enter the hot water supply side metal duct 1 ″ side.

  The apparatus for supplying molten metal to a die-casting sleeve according to the present invention includes a decompression means for sucking molten metal 12 in the pump side duct 1 and intermediate duct 1 ′ into the sleeve 27, and molten metal in the pump side duct 1 and intermediate duct 1 ′. 12 has a hot water supply inductor 14 for applying a braking force to the pump 12, and has an appropriate flow gap for braking the molten metal 12 in the pump side duct 1 and the intermediate duct 1 'so that it does not immediately flow out to the sleeve 27 side during decompression. An annular linear induction electromagnetic pump type molten metal electromagnetic pump having a nozzle level sensor 19 for detecting the molten metal 12 in the pump side duct 1 and the intermediate duct 1 ′ is provided. When the molten metal 12 is supplied to the sleeve 27, the vacuum is reduced by the pressure reducing means before the molten metal 12 is sucked into the sleeve 27 by the pressure reducing means. The molten metal 12 rising in the duct 1 and the intermediate duct 1 ′ is placed with an output to the hot water induction inductor 14 so that a reverse thrust in the opposite direction corresponding to the reduced pressure suction force is generated. The molten metal 12 in the side duct 1 and the intermediate duct 1 ′ is braked and held in the pump side duct 1 and the intermediate duct 1 ′. At this time, the braking force applied to the molten metal 12 in the pump side duct 1 and the intermediate duct 1 ′ by the hot water supply inductor 14 is opposite to the suction direction of the molten metal 12 by the decompression means. In order to brake the molten metal 12, not only the hot water supply inductor 14 but also the rising inductor 24 can be used. The molten metal 12 braked and held in the pump side duct 1 and the intermediate duct 1 ′ is adjusted within a short time to a predetermined position of the nozzle level sensor 19, and by adjusting the output to the hot water supply inductor 14, the pump side duct 1, The required amount of molten metal 12 is supplied to the sleeve 27 by reducing the braking force applied to the molten metal 12 braked in the intermediate duct 1 ′ for a time corresponding to the amount of hot water supply. The molten metal 12 held by the nozzle level sensor 19 also changes its surface due to gasification of hydrogen contained in the molten metal 12, and the molten metal 12 splashes over the nozzle tip to lower the hot water supply accuracy. Therefore, the hot water level must be set at a height that prevents splashes from getting over.

Furthermore, a nozzle tube 45 having a tip cut vertically to cut off hot water is provided in the duct. When the hot water supply of the molten metal 12 is finished and the braking force to the hot water induction inductor 14 is increased again, the molten metal 12 supplied to the sleeve side at the tip of the nozzle tube 45 and the molten metal 12 trying to return to the nozzle side of the electromagnetic pump are generated. When the molten metal 12 is cut at the tip of the nozzle tube 45 having a sharp vertical cut when divided in each direction, accurate hot water supply can be performed. The vertically cut nozzle tube 45 is an elliptical flow path that is formed by cutting the tip sharply in the vertical direction with respect to the pump side duct 1 and the intermediate duct 1 ′ installed at an inclination, and is formed when cut vertically. It has a cross section and a sharp end face in the lower half of the elliptical cross section. In general, the installation angle of the pump-side duct 1 is often 30 ° to 45 °. For example, when the pump-side duct 1 and the intermediate duct 1 ′ are installed at 30 °, the nozzle tube 45 is located at the central axis of the pump-side duct 1, 1 ′. The shape is cut 60 degrees downward. For example, when the pump-side duct 1 and the intermediate duct 1 ′ are installed at 45 degrees, the pump-side duct 1 and the intermediate duct 1 ′ are cut at 45 degrees downward with respect to the central axis of the pump-side duct 1 and the intermediate duct 1 ′. If the installation angle of the pump-side duct 1 and the intermediate duct 1 ′ is reduced, the speed of hot water returning through the duct after hot water supply becomes slow, sharp hot water runs out, and the hot water surface area increases and the hot water supply surface area fluctuation increases the hot water supply accuracy. Since the variation exceeds ± 5%, the inclination angle of the pump side duct 1 and the intermediate duct 1 ′ is preferably 30 degrees or more.

  According to the experiment, when the vertical accuracy of the tip of the nozzle tube 45 exceeds ± 5 degrees, molten metal is applied to the tapered hole 63 side of the ceramic inner tube 61 into which the nozzle tube 45 is inserted from the cut surface of the nozzle tube 45 during hot water supply. The hot water surface that ripples around and adheres to the surface of the nozzle tube 45 that flows over the tip of the nozzle tube 45 causes ripples to occur, resulting in instability of hot water and poor hot water supply accuracy. Therefore, the vertical accuracy of the tip of the nozzle tube 45 should be within ± 5 degrees. This also applies to the accuracy of the installation angle. For example, when the installation angle of the pump side duct 1 and the intermediate duct 1 ′ is 30 degrees and the tip of the nozzle tube 45 is cut to 60 degrees downward with respect to the central axis direction, the accuracy is within ± 5 degrees. Should.

  In such a die-casting sleeve molten metal supply device according to the present invention, an annular linear induction electromagnetic pump type molten metal electromagnetic pump having a channel gap in which swinging up and down of the entire molten metal surface due to inertia force is easily stopped during suction under reduced pressure, Before the predetermined predetermined molten metal 12 is supplied to the sleeve 27, the melting in the pump side duct 1 and the intermediate duct 1 ′ in the direction opposite to the direction in which the molten metal 12 is sucked into the sleeve 27 by the decompression means. A braking force is applied to the metal 12 by the hot water supply inductor 14. The reverse braking force against this flow not only serves as a brake against the flow inertia of the molten metal 12, but if a reverse braking force commensurate with the suction force by the decompression means is applied, the pump side duct 1 and the intermediate duct 1 ' The molten metal 12 inside can be stopped in a short time and without the vertical movement of the molten metal surface. At that time, the hydrogen contained in the molten metal 12 is gasified to cause fluctuations in the molten metal surface, and the stop position is set in the pump-side duct 1 ′ at such a height that the molten metal 12 splashes over the nozzle tip and does not deteriorate the hot water supply accuracy. The stop position is controlled by adjusting the output of the hot water supply inductor 14 in accordance with the signal of the nozzle level sensor 19 installed in the intermediate duct 1 ′, and the pump side duct 1, the intermediate duct 1 ′, the nozzle pipe are controlled from the stop position. The thrust corresponding to the height difference from 45 outlets, Δh and the height H required for hot water supply is reduced for a necessary time. Based on this, hot water supply with high accuracy is made to the die-cast sleeve.

  When the hot water is supplied, the molten metal 12 supplied with high accuracy to the sleeve 27 is not corroded by the metal pipe 1 "because the hot water is cut off at the tip of the nozzle tube 45 that is sharply cut vertically. It flows through the corrosion-resistant ceramic inner tube 61 in the duct 1 ″ and is supplied to the sleeve 27 of the die casting machine. The molten metal 12 supplied to the sleeve is pushed into the die 29 side by the plunger, but vibration of the sleeve 27 occurs when the plunger is started and stopped. This vibration loosens all the packings attached to the pump-side duct 1, the intermediate duct 1 ', the nozzle tube 45, and the metal duct 1 "of the electromagnetic pump, thereby impairing the sealing performance. Therefore, the vibration is absorbed. A bellows 52 was attached to the metal duct 1 ″ to absorb and block the vibration of the sleeve. Accordingly, the ceramic pump side duct 1, the intermediate duct 1 ', the nozzle pipe 45, and the hot water supply side metal duct 1 "of the electromagnetic pump are all sounded without transmitting vibrations that loosen all the packings. Furthermore, since the mouthpiece 62 is used so that the taper packing 59 is not fitted into the insertion part of the ceramic inner pipe 61 and the nozzle pipe 45 of the hot water supply side metal duct 1 ", the vertical cut is made. The soot generated at the tip of the nozzle tube 45 remains inside the ceramic inner tube 61 and does not corrode the hot water supply side metal duct 1 ", and the corrosion resistant ceramic inner tube in the hot water supply side metal duct 1". 61, the molten metal 12 flows. In order to hold the ceramic inner pipe 61 in the hot water supply side metal duct 1 ″ so as not to rattle, a cushion material 60 made of a ceramic fiber is wound around the ceramic inner pipe 61 to support the ceramic inner pipe 61. It is necessary to keep.

As explained above, hot water is supplied to the sleeve 27 with high accuracy without pulsation due to the hot water being cut off at the tip of the lower part of the flow path of the nozzle tube 45 which is sharply cut vertically. When the downward braking force by the electromagnetic pump is increased to finish the hot water supply, the hot water supplied to the sleeve side and the hot water to return to the nozzle side of the electromagnetic pump at the tip of the lower part of the flow path of the nozzle pipe 45 are in the respective directions. However, by forming a sharp end surface in the lower half of the elliptical channel cross section formed when the tip of the nozzle tube 45 is cut perpendicularly to the installation angle, the molten metal 12 is below the channel cross section. When the molten metal 12 descends below half, it is cut naturally at the sharp end face formed in the lower half of the cross section of the flow path of the nozzle tube 45, so that intermittent hot water can be supplied with high accuracy. That is, hot water can be supplied to the sleeve 27 with high accuracy without pulsation by slightly weakening or strengthening the reverse direction thrust corresponding to the suction force by the decompression means according to the pattern. Further, a ceramic inner pipe 61 is built in so that the hot water supply side metal duct 1 ″ is not corroded by the molten metal 12 supplied to the sleeve 27 side, and the ceramic inner pipe 61 and the nozzle pipe 45 are connected at the ceramic inside. A taper hole 63 is formed on the tube 61 side, and a taper packing 59 is fitted into a gap formed by the taper hole 63 and the nozzle tube 45, and the mouthpiece 62 is made to be a narrow step in the nozzle tube 45 in order to maintain the fitting state. It is inserted into the part marked with, and the cushion material 60 made of ceramic fiber is wound around the upper and lower sides where the nozzle pipe 45 of the ceramic inner pipe 61 is inserted so as not to be loose, so that the molten metal can be obtained even in the 59 parts of the taper packing. 12 does not leak, and a ceramic flow path free from corrosion by the molten metal 12 can be formed in all flow paths. It, long life, long electromagnetic pump hot water supply device can be realized with maintenance intervals.

  As described above, according to the present invention, the hot water supply pipe can be hermetically sealed and vacuumed from the die cast sleeve to the electromagnetic pump duct, and the molten metal 12 can absorb the vibration of the sleeve 27 and the thermal expansion of the hot water supply side metal duct 1 ″. The hot water supply side metal duct 1 ″ may be corroded by the molten metal 12 by incorporating the ceramic inner pipe 61 which does not corrode into the hot water supply side metal duct 1 ″ with a joint structure in which the molten metal 12 does not leak. Eliminates the need for an electromagnetic pump-type molten metal supply device with a long maintenance interval and enables stable supply of an accurate amount, enabling casting of uniform quality as well as efficient casting processes. It becomes like this.

It is sectional drawing which shows one Example of a die-casting sleeve molten metal supply apparatus. FIG. 2 is an enlarged view of a main part showing a portion connected to a die casting sleeve 27 from a duct of the die casting sleeve molten metal supply apparatus shown in FIG. 1. It is a graph which shows typically the example of the relationship between the amount of hot metal supply of the molten metal to the sleeve in the die-casting sleeve molten metal supply apparatus, and the drive output of an inductor.

In the present invention, before the predetermined predetermined molten metal 12 is supplied to the sleeve 27, the pump-side duct 1 and the intermediate duct 1 are opposite to the direction in which the molten metal 12 is sucked into the sleeve 27 by the decompression means. By applying a thrust to the molten metal 12 in the molten metal electromagnetic pump, the molten metal 12 is temporarily held in the pump-side duct 1 and the intermediate duct 1 'without vibration in a short time, and the downward holding thrust is used for hot water supply. When the appropriate time is weakened, the molten metal 12 is sucked up to the hot water supply side metal duct 1 "side, and when the hot water supply is finished, at the tip of the nozzle tube 45, the elliptical flow path of the nozzle tube 45 cut sharply and vertically is removed. As the molten metal 12 is lowered at the sharp end surface of the lower half, the molten metal 12 is naturally cut and supplied to the sleeve 27 side and returned to the intermediate duct 1 ′. The constant molten metal 12 is supplied to the sleeve 27 side to complete the hot water supply to the sleeve 27. A ceramic inner pipe 61 that is not corroded by the molten metal 12 is formed in the flow path to the sleeve 27 of the hot water supply side metal duct 1 ". Built-in, the ceramic inner tube 61 is inserted into the nozzle tube 45, and the inserted gap is a tapered hole 63 that becomes narrower toward the inside of the ceramic inner tube 61, and a taper packing 59 is fitted therein. Therefore, the taper packing 59 is not pushed out into the ceramic inner tube 61. Further, the taper packing 59 is inserted by the mouthpiece 62 inserted into the narrow stepped portion of the nozzle tube 45 so that the taper packing 59 is not slipped off. In order to hold down the taper packing 59, the ceramic The cushion material 60 is wound around both sides of the pipe 61 in the vicinity of the nozzle pipe 45 so that the ceramic inner pipe 61 is not rattled in the hot water supply side metal duct 1 ″. A hot water supply side metal duct 1 "is formed. The hot water supply side metal duct 1 "has a bellows 52 that absorbs its own thermal expansion and vibration from the sleeve at the same time. Thus, the molten metal 12 that is clean and not oxidized is supplied to the sleeve 27 because hot water is supplied in a vacuum state, and an electromagnetic pump type vacuum molten metal supply device that enables a high-quality cast product with less maintenance is realized.
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

FIG. 1 shows an embodiment of a molten metal supply apparatus according to the present invention. This molten metal supply apparatus is an example in which molten metal is supplied from the upper side of the sleeve 27, and FIG. 2 is an enlarged view of a main part showing a portion connected to the die casting sleeve 27 from the duct of the die casting sleeve molten metal supply apparatus. . This molten metal supply apparatus has a two-stage inductor of an upper hot water supply inductor 14 and a lower rising inductor 24.
The pump side duct 1 is disposed obliquely, and the lower end of the pump side duct 1 is inserted into the liquid level of the molten metal 12 accommodated in the molten metal tank 11. A hot water supply inductor 14 in which a coil 16 is wound around a yoke 15 made of a magnetic material is disposed around a portion of the pump side duct 1 above the liquid level of the molten metal 12. The yoke 15 is fitted on the outer peripheral side so as to surround a portion of the pump side duct 1 that is above the liquid level of the molten metal 12, and a coil 16 constituting a three-phase coil is wound around the yoke 15. Yes. The hot water supply inductor 14 is provided with a cooler 10 and is cooled during driving.

  Further, a rising inductor 24 is arranged around the portion below the hot water supply inductor 14 in the pump side duct 1. In the same manner as the hot water supply inductor 14, the rising inductor 24 has a coil 26 wound around a yoke 25 made of a magnetic material and fitted on the outer periphery of a portion below the hot water supply inductor 14 of the pump side duct 1. It is a turn. The coil 26 of the rising inductor 24 is wound around an inorganic insulating cable having heat resistance. An inorganic insulated cable has a structure in which a conductive wire is housed in a sheath made of a stainless steel tube or the like, and the conductive wire and the sheath are insulated by filling them with an inorganic insulating powder such as magnesia powder. This is what is called a sheath cable. Such an inorganic insulated cable has high heat resistance and can withstand a temperature of 800 ° C. For this reason, the startup inductor 24 is suitable for energizing a large current while having no cooling without a cooling means, and accordingly, the startup inductor 24 is compared with the coil 16 of the hot water supply inductor 14 by that amount. The number of turns of the coil 26 can be reduced.

  The rising inductor 24 is surrounded by a cylindrical protective case 17 made of heat-resistant ceramic or the like. The upper end opening of the protective case 17 is fixed to the lower end surface of the upper hot water supply inductor 14. The opening at the lower end of the protective case 17 is closely joined to the lower end of the pump side duct 1 via a packing (not shown), and the inside surrounded by the joint is the pump side duct 1. It is the inlet 18 for the molten metal 12 at the lower end.

  The hot water supply inductor 14 and the rising inductor 24 are driven by drive power sources 31 and 32 including inverters, respectively. From these drive power sources 31 and 32, the hot water induction inductor 14 and the rising inductor 24 are respectively energized by the three-phase alternating current converted by the inverter, and a moving magnetic field is generated in the hot water supply inductor 14 and the rising inductor 24. Thrust is given to the molten metal 12 in the pump side duct 1 which is a conductor by electromagnetic induction by this moving magnetic field.

  An intermediate duct 1 ′ is attached to the upper end of the pump-side duct 1 using a presser fitting 42 and a spring 44 via a heat insulating material. Further, the hot water supply side metal duct 1 ", which is an L-shaped elbow pipe whose tip is bent downward, and the nozzle pipe 45 whose tip is vertically cut using the presser fitting 42 'and the spring 44' through a heat insulating material are used. The protective duct 3 is closely connected to the intermediate duct 1 ', and a spacer 7 is provided around one end of the protective pipe 3 near the intermediate duct 1', and the protective pipe 3 and the cores 2 and 22 therein are interposed through the spacer 7. Is held at the center of the pump side duct 1. In this state, the nozzle tube 45 whose tip is vertically cut is incorporated in the intermediate duct 1 'side of the hot water supply side metal duct 1 ". Yes. Further, the pump side duct 1, the intermediate duct 1 ', the hot water supply side metal duct 1 "and the nozzle pipe 45 are all connected by packing, welding or the like so as to ensure airtightness.

  The pump side duct 1, the intermediate duct 1 ', and the nozzle tube 45 having a vertically cut end are made of a heat-resistant and corrosion-resistant material such as ceramic, and are composed of a heat retaining micro heater provided on the outer periphery thereof. Heaters 9, 9 ′, 9 ″ are heated to a temperature higher than the melting point of the molten metal 12 to prevent the molten metal 12 from solidifying. The L-shaped hot water supply side metal duct 1 ″ is made of stainless steel or the like. A ceramic inner tube 61 is built in the inner surface, and is heated to a temperature equal to or higher than the melting point of the molten metal 12 by a heater 9 ″ made of a heat retaining micro heater or the like provided on the outer periphery thereof to prevent the molten metal 12 from solidifying.

The nozzle tube 45 and the ceramic inner tube 61 are formed with a tapered hole 63 on the side of the ceramic inner tube 61 close to the nozzle tube 45, and the nozzle tube 45 is inserted into the tapered hole 63, and the tapered hole 63 of the ceramic inner tube 61. Is a hole that becomes thinner toward the inside, and a taper packing 59 is fitted into the taper hole 63, and the mouthpiece 62 is stuck in a slightly thinned and stepped portion of the stuck nozzle tube 45. The taper packing 59 is prevented from sliding down. Since this taper packing 59 is fitted into a gap formed by the taper hole 63 of the ceramic inner pipe 61 and the nozzle pipe 45 pierced and supported by the mouthpiece 62, the molten metal 12 is made of a metal on the hot water supply side metal. There is no leakage to the duct 1 ″ side. A band-like cushion material 60 of ceramic fibers is used to support the ceramic inner tube 61 so that the ceramic inner tube 61 does not rattle in the hot water supply side metal duct 1 ″. The tube 61 is wound around both sides of the vicinity of the nozzle tube 45 pierced. Since the cushion material 60 made of a ceramic fiber band is wound around the both sides of the nozzle pipe 45 of the ceramic inner pipe 61 for supporting the ceramic inner pipe 61, the thermal expansion of the hot water supply side metal duct 1 "is caused by the sleeve 27. The ceramic inner tube 61 does not generate excessive thermal stress.

Since the bellows 54 is tightly attached between the hot water supply side metal duct 1 "and the sleeve 27 via a coupling 56 including an O-ring (not shown), the thermal expansion of the hot water supply side metal duct 1" itself. The bellows 52 can absorb the vibration associated with the start and stop of the plunger 28 in the sleeve 27, and a vacuum can be maintained. Accordingly, no excessive thermal stress is generated in the hot water supply side metal duct 1 ". If the coupling 56 is removed, the electromagnetic pump, the pump side duct 1, the intermediate duct 1 ', the hot water supply side metal duct 1" And maintenance of the sleeve 27 of the die casting machine can be performed.

A liquid level sensor 13 is provided on the molten metal 12 in the molten metal tank 11, whereby the liquid level of the molten metal 12 in the molten metal tank 11 is detected. The rising inductor 24 is inserted below the liquid level of the molten metal 12 detected by the sensor 13.
On the other hand, a nozzle level sensor 19 such as an inductive liquid level sensor that detects the presence of the molten metal 12 by electromagnetic induction is provided in the intermediate duct 1 ′, thereby detecting the liquid level in the intermediate duct 1 ′. .

  The tip of the hot water supply side metal duct 1 ″ is connected to the upper portion of the sleeve 27 via the bellows 54, and the molten metal 12 can be supplied to the sleeve 27 from the hot water supply side metal duct 1 ″ incorporating the ceramic inner pipe 61. . The sleeve 27 is a cylindrical cylindrical member in which a plunger 28 is disposed. The plunger 28 moves left and right in the sleeve 27 in FIG. 1 and pushes out the molten metal 12 supplied into the sleeve 27. The plunger 28 incorporates a molten metal sensor 36 such as a thermocouple embedded type or an induction type, and detects the molten metal 12 supplied into the sleeve 27.

Further, a die 29 is connected to the tip of the sleeve 27, and the molten metal 12 supplied to the sleeve 27 is filled into the die 29 from the tip of the sleeve 27 by the operation of the plunger 28. The mold 29 is driven by a mold drive mechanism (not shown), and assembly and demolding are performed.
The die 29 is connected to a decompression pump 35 via an electromagnetic valve 33 and a vacuum tank 50 via an electromagnetic valve 39. In order to instantaneously evacuate the cavity 46 and the sleeve 27 of the mold 29, a decompression pump 35 having a very large exhaust capacity is required, and the exhaust capacity of the decompression pump 35 is limited. If the vacuum tank 50 is evacuated and the electromagnetic valve 39 and the electromagnetic valve 33 are opened at the same time, a large-capacity exhaust pump can be formed by the decompression pump 35 and the vacuum tank 50. When the electromagnetic valve 40 is also opened simultaneously, The cavity 46 and the sleeve 27 of the mold 29 can be evacuated in a short time. Although determined by the size of the vacuum tank 50, the cavity 46 and the sleeve 27 of the mold 29 can be evacuated in a short time in about 3 seconds. In order to further increase the vacuum in the cavity 46 and the sleeve 27 in this state, the vacuum tank 50, the cavity 46 and the sleeve 27 are simultaneously set in a high vacuum only by the decompression pump 35, which takes time. By stopping the electromagnetic valve 39 on the vacuum tank 50 side, the inside of the mold 29 and the sleeve 27 is decompressed to a high vacuum only by the decompression pump 35 through the electromagnetic valve 40 and the electromagnetic valve 33. Thereby, the molten metal 12 is supplied into the sleeve 27 in a state where the air in the mold 29 and the sleeve 27 is excluded, and the molten metal is smoothly transferred from the sleeve 27 to the mold 29 by the operation of the plunger 28 after the hot water supply. In addition, it can be filled to every corner.

However, when the molten metal 12 is an aluminum alloy, the specific gravity is about 2.5 g / cm ³ , so that the atmospheric pressure was applied when the mold 29 was decompressed to near vacuum (about −1.0 kg / cm ² G). Since the molten metal 12 accommodated in the molten metal tank 11 is pumped by about 4 m, the molten metal 12 is filled in the entire space from the sleeve 27 to the mold 29 even if the plunger 28 is not operated. Even if the pressure of the mold 29 is about half the atmospheric pressure (about −0.5 kg / cm ² G), the molten metal 12 can be pumped up to about 2 m at atmospheric pressure. The entire space from 27 to the inside of the mold 29 is filled. Therefore, the molten metal is generated by generating a thrust opposite to the hot water supply direction in an electromagnetic pump that can output a pressure exceeding the differential pressure by making the air pressure in the mold 29 vacuum (-1.0 kg / cm ² G) at once. 12 is braked and held in the pump-side duct 1 and the intermediate duct 1 ′, and the electromagnetic force of the molten metal electromagnetic pump that generates an electric force that is easy to control is adjusted to weaken or strengthen, and the melt that is braked and held is adjusted. The metal 12 is supplied to the sleeve 27 by a constant amount of hot water.

However, simply by generating a moving magnetic field so that a thrust is generated in the opposite direction to the hot water supply when the mold 29 is evacuated, the molten metal contained in the molten metal tank 11 under atmospheric pressure is applied. 12 is a fluid of the molten metal 12 even when a braking force is generated in the molten metal 12 running up the pump side duct 1 and a reverse thrust is applied that balances to a predetermined set level 30 of the intermediate duct 1 ′. Due to inertia, the molten metal 12 passes the predetermined set level 30. The molten metal surface is swung up and down due to fluid inertia, and it takes time for the rocking to stop. Further, since the distance between the predetermined set level 30 of the intermediate duct 1 ′ and the vertically cut nozzle pipe 45 is short, the molten metal 12 gets over the sleeve 27 and droops before hot water supply. With this, it is not possible to expect a constant amount of hot water supply to the sleeve 27.

Therefore, the simplest method is to apply electric power to the hot water supply inductor 14 so that thrust is generated in the direction opposite to the hot water supply direction corresponding to the suction force by the decompression means, and slowly move the mold 29 and the sleeve 27 slowly. It is to make a vacuum. Then, a reverse magnetic force is generated in the molten metal 12 that slowly rises in the pump-side duct 1, and the molten metal 12 is once held in the pump-side duct 1 and the intermediate duct 1 ′, and then accurately and quickly molten metal to the sleeve 27. Supply control. For this reason, hot water can be supplied to the sleeve 27 without pulsation by slightly weakening or strengthening the reverse thrust corresponding to the suction force by the decompression means according to the pattern.

This is very easy to control, but it takes a few minutes to supply water from the vacuum, and it takes a cycle time for the die casting method that is operated in about 1 minute, leading to an increase in cost and is not practical. Furthermore, even if the molten metal 12 runs up in the pump side duct 1 and the intermediate duct 1 ′ and the molten metal level is set to a predetermined set level 30 using the nozzle level sensor 19, the hydrogen in the molten metal 12 is gasified on the molten metal surface. As a result, the molten metal 12 gets over the vertically cut nozzle tube 45 and the hot water supply accuracy is lowered.

Since the splash of the molten metal 12 adheres to the inner duct 1 ′ and the inner surface of the vertically cut nozzle tube 45, air flows into the pump side duct 1 when the mold 29 is open. 1. The molten metal 12 adhering to the inner surface of the intermediate duct 1 ′ is oxidized by contact with air. In this case, since the oxide film of the molten metal 12 adhering to the inner surface is supplied at the time of the next hot water supply, the mold 29 is filled with the molten metal 12 containing as little oxide as possible to make a high-quality cast product. It does not meet the purpose of the vacuum die casting method. Therefore, after the hot water supply to the sleeve 27 is completed, the plunger moves and passes through the opening of the sleeve 27, and then an inert gas such as nitrogen gas is injected from the inert gas tank 38 through the electromagnetic valve 37 to the back opposite to the moving direction of the plunger 28. However, there is a need for a mechanism in which an inert gas is naturally injected into the L-shaped hot water supply side metal duct 1 ″ on the electromagnetic pump side, the nozzle pipe 45 with the tip vertical cut, the intermediate duct 1 ′, and the pump side duct 1 as well. Become.

  The pump-side duct 1 of the annular linear induction electromagnetic pump used this time has a protective tube 3 containing cores 2 and 22. By reducing the annular flow gap between the protective tube 3 and the pump-side duct 1, The pump side duct 1 has a flow restricting effect like an orifice, and a brake is applied to the molten metal 12 that is about to rise from the inlet 18 of the molten metal 12 at the lower end of the pump side duct 1. According to experiments, it was found that when the flow gap is 10 mm or less, the height rising due to inertia is small, and the flow gap is stabilized within a few seconds. It takes about 5 seconds, which is slightly longer than several seconds. However, if the channel gap is set to 15 mm or less, the flow is stabilized in a relatively short time. In this way, when the inside of the hot water supply side metal duct 1 ″ including the pump side duct 1, the intermediate duct 1 ′, and the vertical cut nozzle pipe 45 is evacuated by narrowing the flow path gap, the molten metal that runs up the pump side duct 1. 12 can be held at the set level 30 of the intermediate duct 1 'in a short time.

Even if the setting level 30 is set in this way, the atmospheric pressure fluctuates, and even if it fluctuates by 1%, the height rising in the vacuum changes by about 4 cm. 19, the reverse thrust of the electromagnetic pump is adjusted within a short period of time, and is set to the set level 30 in the vacuum. Furthermore, since the hydrogen contained in the molten metal 12 is gasified, molten metal surface fluctuations and splashes occur, and the molten metal 12 overflows from the vertically cut nozzle tube 45. According to experiments, the amount of hydrogen contained in the molten metal 12 is also measured. However, when there is little hydrogen, the setting level 30 must be provided at a height of 5 cm below the lower outlet of the vertically cut nozzle tube 45. When the amount of hydrogen contained in 100 g of molten metal 12 reaches several cc / 100 g, it is necessary to provide a setting level 30 10 cm or more below the lower outlet of the vertically cut nozzle tube 45. It is necessary to lower the setting level 30 as the amount of hydrogen contained in the molten metal 12 increases. This means that the nozzle level sensor 19 is gradually lowered below the vertical cut surface of the nozzle tube 45. Generally, the thickness of the nozzle tube 45 is about φ50 to φ80, and therefore the thickness of the nozzle level sensor attached outside the nozzle tube 45 is φ70 to φ100. The measurement range in the duct axis direction of the inductive nozzle level sensor 19 is up to the same distance as the coil diameter of the nozzle level sensor 19 in the vertical direction. Therefore, when the set level is lowered to 10 cm or more from the lower outlet of the nozzle tube 45 that has been cut vertically due to the influence of hydrogen gas, and the nozzle level sensor 19 is also lowered at the same time, the nozzle level sensor 19 makes the vertical cut surface of the nozzle tube 45 lower. The nozzle level sensor 19 cannot determine the depth Δh of the molten metal 12 that overflows, and even the presence or absence of overflow. Therefore, in the case of a vacuum molten metal hot water supply device, a new overflow level sensor 55 is required to confirm the presence or absence of the molten metal 12 flowing over the vertical cut surface of the nozzle tube 45 and the depth Δh of the molten metal 12. become. As a result, the presence or absence of the molten metal 12 flowing over the vertical cut surface of the nozzle tube 45 and the depth Δh of the molten metal 12 can be reliably measured, so that hot water can be supplied with high accuracy.

  After setting the molten metal 12 level at the set level 30, the direction is opposite to that of a general electromagnetic pump, but the output is required from the level 30 to flow over the top of the hot water supply side metal duct 1 ". It is necessary to weaken the hot water surface to a height FL up to the height FL, that is, the height H between the set level 30 and the lower end of the upper outlet of the nozzle pipe 45 and the height difference Δh. A predetermined amount of hot water is ensured by maintaining the amount of hot water supplied for a long time. When the hot water is to be terminated, the molten metal 12 flows toward the sleeve 27 through the L-shaped hot water-side metal duct 1 ". Then, the molten metal 12 returning to the intermediate duct 1 ′ side is divided so as to be cut by the vertically cut nozzle tube 45, so that hot water can be supplied with high accuracy.

  In order to raise the molten metal 12 to the height above the level difference Δh between the overflow height FL and the lower end of the upper outlet of the nozzle tube 45, the measured value of the level meter 13 of the holding furnace 11 and the height of the set level 30 are used. This is achieved by automatically calculating the amount of electromagnetic force reduction corresponding to the level difference Δh necessary for flow rate calculation, and applying the amount of reverse electromagnetic force reduction from the calculated value to the hot water supply inductor 14 to the drive power supply 31. It is done. However, in order to determine whether or not the molten metal 12 has actually reached the height of Δh and the hot water has been reliably supplied, it is preferable that the overflow level sensor 55 is disposed as close to the tip of the nozzle tube 45 as possible. If there is no overflow level sensor 55 and the molten metal sensor 36 of the plunger 28 is operated with or without a failure, and clogging occurs for some reason inside the nozzle tube 45, the molten metal 12 supplies hot water to the sleeve 27. Since there is a possibility that the plunger 28 moves to the mold 29 side and collides at a high speed by a hydraulic mechanism including an accumulator (not shown) in an empty state without being performed, the molten metal 12 of the overflow level sensor 55 It is also important to determine whether there is overflow.

  As can be understood from the above description, the force applied to the molten metal 12 flowing over the vertically cut nozzle tube 45 is the atmospheric pressure applied to the molten metal 12 in the molten metal tank 11. This pressure is a static pressure with respect to the molten metal 12 of the open furnace without a sealing lid, and is not a dynamic pressure having a cushioning property that takes time to flow into the closed furnace, so that the operation of the molten metal 12 is delayed. Absent. Therefore, in order to avoid such a dynamic pressure problem, the furnace for the electromagnetic pump must be an open well (open furnace). An open well is desirable because it reduces costs and improves maintainability.

  The sleeve 27 has considerable vibration and displacement when the plunger starts to move, when the mold is opened, and when the mold is clamped, so that damage is caused to the packing at the connecting portion of the hot water supply side metal duct 1 ″, the intermediate duct 1 ′, and the pump side duct 1. The displacement of the sleeve 27 is as much as 1 mm to 2 mm, and this displacement must be absorbed, and the thermal expansion of the L-shaped hot water supply side metal duct 1 "must also be absorbed. Therefore, in FIG. 1, a bellows 52 is inserted between the sleeve 27 and the hot water supply side metal duct 1 "to absorb these vibrations and thermal expansion, and the sleeve 27, the hot water supply side metal duct 1" and the intermediate duct 1 are absorbed. In order to keep the space up to the pump side duct 1 in a sealed space, the hot water supply side metal duct 1 ”made of stainless steel and the bellows 52 have a welded structure. The bellows 52 and the sleeve branch pipe 57 have a built-in seal O-ring (not shown). In this structure, the sleeve 27 side, the electromagnetic pump side duct 1, the intermediate duct 1 ′, and the hot water supply side metal 1 ″ side can be maintained by removing the coupling 56. In addition, since the plunger inside the sleeve 27 is lubricated on the hot water supply port of the sleeve 27, the spray nozzle 53 that can inject a lubricant from the lubricating oil tank 49 through the electromagnetic valve 51 can be moved up and down while maintaining a sealed state. It was set as the structure inserted through the bellows 34. An inert gas tank 47 is connected to the bellows 34 via an electromagnetic valve 48. The bellows 34 and 52 have a quick coupling structure to facilitate maintenance of the sleeve 27.

Next, the best operation method of the present invention is shown below. When this molten metal supply device is operated, first, the molten metal 12 in the pump-side duct 1 is pumped up to a height at which the electromagnetic force of the hot water supply inductor 14 acts by energizing the start-up inductor 24, and then the induction type. Based on the signal from the nozzle level sensor 19 and the like, a three-phase alternating current is supplied to the hot water induction inductor 14 to adjust the molten metal 12 in the pump side duct 1 and the intermediate duct 1 ′ to an appropriate level, for example, a solid line in FIG. The setting level 30 shown is maintained. At this set level 30, the molten metal 12 is brought into a standby state. Thereafter, the mold 29 and the sleeve 27 are linearly depressurized, and at the same time, the electromagnetic force in the hot water supply direction of the hot water supply inductor 14 is lowered. Liquid pressure, for example, the molten metal 12 has a specific gravity of 2.5 g / cm ³ and the set level of the molten metal 12 stored in the molten metal tank 11, the duct 1, and the molten metal 12 in the intermediate duct 1 ′. since the height of the 30 its hydraulic pressure Datosuruto 1m corresponds to about 0.25 kg / cm ² G, the set level 30 even when it becomes a vacuum pressure of about -0.25kg / cm ² G was maintained, when the Inverting the phase of the electric power to the hot water supply inductor 14 and applying the reverse thrust in the direction opposite to the hot water supply direction continues the pressure reduction of the mold 29. The reverse pressure of the hot-water supply inductor 14 at the time when the reduced pressure of the mold 29 is in a vacuum state (about −1.0 kg / cm ² G) is the same as that of the molten metal 12 stored in the molten metal tank 11. The liquid pressure corresponding to a height of 1 m with the set level 30 of the molten metal 12 in the pump side duct 1 and the intermediate duct 1 ′ is about 0.75 kg / cm ² G because about 0.25 kg / cm ² G is applied. The level 30 position indicated by the solid line in FIG. 1 is sufficiently maintained. When the reverse thrust of the three-phase alternating current energized in the hot water supply inductor 14 is weakened, as indicated by the two-dot chain line in FIG. 1, the reverse thrust corresponding to the height FL necessary to overflow the hot water supply side metal duct 1 " As shown by a two-dot chain line in FIG. 1, the molten metal 12 flows over the vertically cut elliptical opening of the nozzle pipe 45 in the hot water supply side metal duct 1 ″ and supplies hot water to the sleeve 27 to which the molten metal 12 is supplied. Is done.

Since it is difficult to control to maintain the hot water surface holding setting level 30 in the intermediate duct 1 ′ after the hot water supply, the hot water supply operation of the molten metal 12 is completed, the plunger starts moving, and the plunger opens the opening of the sleeve 27. After passing, inert gas is injected from the inert gas tank 47 through the electromagnetic valve 48 in the vicinity of the bellows 34 of the hot water supply side metal duct 1 ", and at the same time, the reverse thrust of the electromagnetic pump is reduced to zero and the intermediate duct 1 'and pump It is also possible to return the molten metal surface in the side duct 1 to the same molten metal surface as the molten metal tank 1. In this way, the molten metal surface in the pump side duct 1 becomes the same as the molten metal tank surface, and the pump Since the side duct 1, the intermediate duct 1 ′, and the hot water supply side metal duct 1 ″ are filled with the inert gas, the molten metal 12 is not oxidized. Further, since the pump side duct 1, the intermediate duct 1 ′ and the hot water supply side metal duct 1 ″ are filled with inert gas, the rising metal 24 is used to hold the molten metal 12 at the hot water surface holding setting level 30 from the beginning. The control for maintaining the pressure on the mold 29 is stopped, and a reverse electromagnetic force sufficient to withstand the vacuum pressure on the mold 29 side of −1.0 kg / cm ² G is simply applied only to the hot water supply inductor 14, and the pump is operated when the mold 29 is depressurized. Control may be performed in which the molten metal 12 is braked in the side duct 1 and the molten metal 12 is maintained at the molten metal surface holding setting level 30 of the intermediate duct 1 ′. Although the molten metal 12 moves up and down, since the oxidation of the molten metal 12 is suppressed by providing an inert gas injection system, it served the purpose of casting the beautiful non-oxidized molten metal 12 that was the original purpose. The simplest control method In it. This patent is simple the method and the pump-side duct 1, which also describes the best method of molten metal 12 does not vertically through the intermediate duct 1 '.

In this way, hot water can be supplied to the sleeve 27 without pulsation by slightly weakening or strengthening the reverse thrust corresponding to the suction force by the decompression means according to the pattern. The level difference of the molten metal 12 at the time of hot water supply and at the time of hot water supply standby is a height FL necessary for overflowing the hot water supply side metal duct 1 ″, and in FIG. The flow rate can be calculated by applying to the flow rate calculation formula based on the principle of the weir flow meter while taking into account the flow area of Δh and Δh of the elliptical outlet of the vertically cut nozzle pipe 45. The power that weakens the reverse thrust of the electromagnetic pump corresponding to the total height of H and Δh can be calculated from the output characteristics of the electromagnetic pump, whereby the difference between the reverse power of the three-phase alternating current that flows through the hot water supply inductor 14 and the hot water supply time. Thus, the amount of hot water supply is known, and the supply amount necessary for casting is supplied to the sleeve 27. Furthermore, since the above-described Δh can be measured by an overflow type sensor 55 such as an induction type, the hot water supply inductor 14 is adjusted so that the required Δh is obtained. Control The supply amount using the calculation formula of the weir flowmeter from the hot water supply time and Δh is known, can be grasped more accurately the hot water supply amount.

  As apparent from the above description, the sleeve 27 is supplied with a predetermined amount of molten metal 12, that is, a single amount of molten metal 12 to be filled in the mold 29. As shown by a two-dot chain line L in FIG. 1, the amount is about half of the maximum volume of the normal sleeve 27 (the volume when the plunger 28 is most retracted). The amount of molten metal 12 supplied to the sleeve 27 can also be detected by a molten metal sensor 36 built in the plunger 28.

In this way, a predetermined amount of the molten metal 12 is supplied to the sleeve 27, and at the same time, the level of the molten metal 12 is returned to the set level 30 indicated by the solid line in FIG. As described above, the level difference of the molten metal 12 between the hot water supply and the hot water supply standby is the height indicated by Δh + H in FIG. When the hot water supply to the sleeve 27 is completed, the solenoid valve 33 and the electromagnetic valve 32 are closed, and then the plunger 28 starts to move slowly, and the plunger 28 is moved to an L-shape by a signal from a movement position detector (not shown). When the lower opening of the sleeve branch pipe 57 of the hot water supply side metal duct 1 "connected from the hot water supply side metal duct 1" to the sleeve 27 is closed, the reverse thrust in the direction opposite to the hot water supply direction of the hot water supply inductor 14 is instantaneously zeroed. Invert the phase. After that, since the plunger 28 moves slowly, the opening in the sleeve 27 of the supply side metal duct 1 ″ is located on the back side of the plunger 28 with respect to the moving direction of the plunger 28. The plunger of a general die casting machine Since the back surface of 28 is open to the atmosphere, the air suddenly flows in, and the molten metal 12 in the pump-side duct 1 and the intermediate duct 1 ′ instantaneously returns to the molten metal tank 11. When the air enters, the pump Since the set level 30 in the side duct 1 and the intermediate duct 1 ′ cannot be maintained and the molten metal 12 is oxidized, the set level 30 in the pump side duct 1 and the intermediate duct 1 ′ is not lowered, and the molten metal As shown in FIG. 1, the pressure at which the back surface of the plunger 28 is maintained at the set level 30 in the pump-side duct 1 and the intermediate duct 1 ′, for example, melting so as not to oxidize 12 If the height of the molten metal 12 stored in the metal tank 11 and the set level 30 of the molten metal 12 in the duct 1 and the intermediate duct 1 ′ is 1 m, it is maintained at about −0.25 kg / cm ² G. If possible, this back pressure gas is preferably an inert gas, and is supplied from the inert gas tank 38 via the valve 37. Further, the plunger 28 moves slowly thereafter, and the sleeve 27 is filled with the molten metal 12. The plunger 28 moves at a high speed by a hydraulic mechanism including an accumulator (not shown) as in a normal die casting machine, and the mold 29 is filled with the molten metal 12, and after the filling is completed, the plunger 28 is further slowly pushed to solidify the molten metal 12. Casting is completed by compensating for the shrinkage.

Although it should not be said again, in order to simplify the apparatus, the inside of the hot water supply side metal duct 1 ″, the intermediate duct 1 ′, and the pump side duct 1 on the electromagnetic pump side described here is about −0.25 kg / cm ² G. Since a new reduced pressure supply system is required to maintain the pressure, the output of the electromagnetic pump is turned off, and only the inert gas is supplied to the atmospheric pressure. It may be lowered to the same level as the molten metal surface of the molten metal 12 stored in the metal tank 11. In this way, the molten metal surface in the pump side duct 1 is the same as the molten metal surface of the molten metal tank, and the pump side duct 1, If the intermediate duct 1 ′ and the hot water supply side metal duct 1 ″ are filled with an inert gas, the control to maintain the molten metal 12 at the hot water surface holding setting level 30 using the rising inductor 24 is stopped, and simple. In the hot water supply inductor 14 only, vacuum on the mold 29 side Keep in inverse-electromagnetic force to withstand the force -1.0kg / cm 2 ^G, and brake the molten metal 12 in the pump duct 1 during mold 29 side vacuum, molten metal surface retention level of the intermediate duct 1 ' It may be controlled to maintain the molten metal 12 at 30.

After the casting is completed and the mold 29 is opened and a cast product (not shown) is taken out, the plunger 28 returns to the inside of the sleeve 27. The plunger 28 is connected to the hot water supply side duct 1 "of the sleeve 27 and is connected to the opening. After passing, the air suddenly flows from the mold 29 side to the duct 1 side of the electromagnetic pump, so the electromagnetic valve 48 of the inert gas tank 47 having the same pressure as the atmospheric pressure is opened before the plunger 28 starts to return in advance. Nitrogen gas is filled into the duct 1 side of the electromagnetic pump.At the time before this gas injection, the inside of the pump side duct 1, the intermediate duct 1 ', and the hot water supply side metal duct 1 "is opened from the inert gas tank 38 to the valve 37. The molten metal 12 is held at the set level 30 while maintaining the pressure at about −0.25 kg / cm ² G via the plunger. When 28 begins to return, the electromagnetic valve 48 of the inert gas tank 47 is opened to increase the output of the hot water supply inductor 14 while supplying gas linearly to the pump side duct 1, the intermediate duct 1 ', and the hot water supply side metal duct 1 ". Increase the direction to maintain the set level 30. When the plunger 28 begins to return, the pump side duct 1, the intermediate duct 1 ', and the hot water supply side metal duct 1 "are filled with an inert gas at the same pressure as the atmospheric pressure. However, since the mold 29 is open, air is drawn from the mold 29 side and the plunger 28 returns, so the speed of the plunger 28 is slowly returned in front of the opening of the hot water supply side metal duct 1 ″ of the sleeve 27. Further, the plunger 28 is moved slowly so that air inflow from the mold 29 side does not occur at once. Based on 示値 adjusts the driving power source 31 so as to maintain a set level 30 increases the electromagnetic force of the hot water supply inductor 14 in the hot water direction.

As described above, in order to simplify the apparatus and the operation, before the plunger 28 starts to return, the electromagnetic valve 48 of the inert gas tank 47 having the same pressure as the atmosphere is opened, and the hot water supply side metal duct 1 "on the electromagnetic pump side. If the inside of the intermediate duct 1 ′ and the pump side duct 1 is already filled with an inert gas such as nitrogen gas, the level sensor 19 of the duct 1 must hold the hot water level at the level 30 in the intermediate duct 1 ′. However, since the air is drawn from the mold 29 side when the plunger 28 returns, the hot water supply side metal duct 1 "and the hot water supply metal side duct 1" on the electromagnetic pump side, the intermediate duct 1 'Because air gradually enters the pump-side duct 1, the control method of keeping the molten metal level at level 30 has an effect of preventing generation of oxide as much as possible.

  FIG. 3 schematically shows the optimum operation of the hot water supply and braking of the molten metal 12, that is, the best method in which the molten metal 12 does not move up and down in the pump side duct 1 and the intermediate duct 1 ′. The output of the hot water supply inductor 14 until the molten metal 12 accommodated in the molten metal tank 11 reaches a predetermined set level 30 in the pump side duct 1 and the intermediate duct 1 ′ is a positive hot water supply output in a direction against gravity. It is described as (+), and it is switched from positive (+) to negative (−) in the gravitational direction until the pressure of the mold 29 is reduced and vacuum is reached, and the pump side duct 1 is arranged so as to send the molten metal 12 to the sleeve 27. The thrust to the molten metal 12 in the duct 1 ′ is weakened, and the hot water flows into the sleeve 27 through the nozzle pipe 45 of the tip vertical cut. When the molten metal 12 in the sleeve 27 reaches a predetermined level L, the output of the inductor 14 increases the negative (−) output so as to return to the set level 30 in the pump-side duct 1 and the intermediate duct 1 ′ and melts. A reverse thrust is applied to the metal 12 in the opposite direction to the hot water supply to brake the metal 12. By doing so, the pressure reducing means such as the pressure reducing pump 35 or the vacuum tank 34 is controlled against the atmospheric pressure from the molten metal tank 11 side applied to the molten metal 12 in the pump side duct 1 and the intermediate duct 1 ′. An annular linear induction electromagnetic pump-type molten metal electromagnetic pump having an appropriate flow gap is effective in suppressing the flow inertia of the molten metal 12. As a result, excessive molten metal 12 is supplied to the sleeve 27 during braking of the molten metal 12, and the pulsation of the molten metal 12 in the pump-side duct 1 and the intermediate duct 1 ′ due to a sudden stop of the molten metal 12 is achieved. Etc. are suppressed.

  After the casting is taken out from the mold 29, a mold release agent is applied to the inner surface of the mold 29 by a dedicated spray (not shown). Further, when the plunger 28 returns to the original position after passing through the opening of the hot water supply side metal duct 1 ″ of the sleeve 27, the spray nozzle 53 for applying the lubricant for the sleeve 27 is pushed down to the center of the sleeve 27. After that, the lubricant is sprayed into the sleeve 27. This prevents the plunger 28 from being gnawed by the inner surface of the sleeve 27 and prevents the inner surface of the sleeve 27 from being corroded by the molten metal 12.

  A predetermined amount of molten metal 12 supplied to the sleeve 27 is then pushed out from the sleeve 27 to the mold 29 by a stroke operation of the plunger 28, filled, and cast. At this time, since the air in the mold 29 is previously eliminated by the decompression means such as the decompression pump 35 and the vacuum tank 34, the mold 29 is completely filled with a certain amount of molten metal 12 without entraining gas. The As a result, the die cast product becomes a high-quality product free from gas and voids.

  The molten metal supply apparatus according to the present invention quickly supplies the sleeve 27 with a precise amount of molten metal 12 without oxidizing and entraining gas by adjusting the outputs of the pressure reducing means, the hot water supply inductor 14 and the rising inductor 24. Therefore, it can be used in the field of die casting where the molten metal 12 is filled by the sleeve 27.

1 Pump side duct 1 'Intermediate duct 1 "Hot water supply side duct 2 Core 3 Protective tube
6 Top of hot water supply side duct
DESCRIPTION OF SYMBOLS 11 Molten metal tank 12 Molten metal 14 Hot-water supply inductor 19 Nozzle level sensor 22 Core 24 Standing inductor 27 Sleeve 28 Plunger 29 Mold 30 Setting level 31 Drive power supply 45 Nozzle pipe 52 Bellows 59 Taper packing 60 Cushion material 61 Ceramic inner pipe

Claims (6)

Inductors (14), (24) for applying thrust to the molten metal (12) to the ducts (1), (1 ′) for conveying the molten metal (12) from the molten metal tank (11) to the sleeve (27) of the die casting ) is provided, this duct (1), at the tip, the molten metal supply unit connected to the hot water supply side duct to the hot water supply (1 ") the molten metal (12) wherein the sleeve (27) of (1 '), said hot water supply A vibration-absorbing bellows (52) is provided between the side duct (1 ″) and the sleeve (27), and the hot water supply side duct (1 ″) is descended from climbing in the hot water supply direction of the molten metal (12). And a ceramic inner pipe (61) is incorporated in the descending slope portion on the sleeve (27) side from the top (6) of the hot water supply side duct (1 "). The downward slope portion of the duct (1 ″) and the ceramic A ceramic belt-like cushioning material (60) is inserted between the inner pipe (61) and the top of the hot water supply side duct (1 ″) (6) to the upward slope portion on the molten metal tank (11) side. A nozzle tube (45) is built in, and at the top (6) of the hot water supply side duct (1 ″), a tapered hole (63) provided with the tip of the nozzle tube (45) on the peripheral surface of the ceramic inner tube (61). ), And a mouthpiece (62) inserted into the gap between the taper hole (63) and the nozzle tube (45) with a taper packing (59) fitted into a step on the peripheral surface of the nozzle tube (45). ) To hold the taper packing (59) so that it does not slide down . The molten metal (12) is supplied to the sleeve (27) after the molten metal (12) is supplied to the predetermined molten metal surface position in the ducts (1) and (1 ′) by driving the inductor (14). The die cast sleeve molten metal supply device according to claim 1, further comprising a drive power source (31) for driving the inductor (14) to be braked and a control panel. 3. The die-cast sleeve molten metal supply device according to claim 1, wherein a supply system for supplying an inert gas is attached to the back side of the plunger (28) of the sleeve (27). An inert gas injection means for injecting an inert gas into the sleeve (27) from the vicinity of the opening of the sleeve (27) connected to the duct (1 ") after casting is provided. The die-cast sleeve molten metal supply apparatus according to any one of the above. The die-casting sleeve molten metal supply apparatus according to any one of claims 1 to 4, wherein an overflow level sensor (55) is provided at a tip of the nozzle pipe (45). The overflow level sensor (55) provided at the tip of the nozzle pipe (45) confirms the presence or absence of overflow, and can also measure the overflow depth of the molten metal (12) flowing over and convert the flow rate. The die-cast sleeve molten metal supply device according to claim 5.

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