JP6324871B2 - Vacuum casting equipment - Google Patents

Description

In the present invention, an upper mold and a lower mold are stacked one above the other to form a cavity therein, and the interior surrounded by the vacuum pump and the bellows connected to the vacuum pump is brought into a depressurized state. A vacuum casting machine that draws molten metal from a stalk connected to a sprue provided at the bottom of the lower mold and molds a cast by vacuum casting and bellows. The present invention relates to a vacuum casting apparatus .

  Conventionally, when an aluminum casting is manufactured, a low pressure casting apparatus is used as a mold for casting a molten metal from below by filling a mold cavity with a relatively low pressure. In a general low-pressure casting machine, an upper mold and a lower mold are stacked one above the other to form a cavity, and gas is injected into the sealed furnace from the stalk that rises from the sealed furnace at the bottom of the lower mold. By doing so, the molten metal is filled into the cavity, and a casting is formed. The lower mold is fixedly installed on a base plate to which the upper end of Stoke is connected. The upper mold is moved up and down by a lifting mechanism equipped with a hydraulic cylinder or the like, and the upper and lower molds are overlapped and detached by the lifting mechanism. The type is done.

  In order to inject molten metal into the cavity at a relatively low pressure, for example, a gas such as an inert gas or carbon dioxide is added to a closed furnace containing the molten metal, and the molten metal is injected through stalk rising from the closed furnace. To do. As a method for filling the cavity with molten metal from the stalk connected to the gate provided in the lower part of the lower mold without using the closed furnace, for example, it is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2014-104469). In addition, there is a method of pumping molten metal from a molten metal tank, which is a melting furnace, with an electromagnetic induction pump and filling the cavity of the mold through stalk. The low pressure casting method is known as a method for producing a good casting with less entrainment of gas and oxide because molten metal is slowly poured from under the mold. However, since the molten metal is poured slowly, the mold is set to about 400 ° C. so that the molten metal does not immediately solidify, and after casting, the mold is cooled to 300 ° C. or lower, and the casting is taken out from the mold. There is a problem that it takes cooling time and the casting cycle time is relatively long.

  In addition, the cavity is evacuated and cast as a casting device to prevent air entrainment in the mold cavity and to obtain a high-quality casting with fewer defects such as nests and voids generated in the casting. A vacuum casting apparatus has been developed in which a die casting machine, which is a high-pressure casting apparatus to perform, is modified. A vacuum casting apparatus is disclosed in, for example, Patent Document 2 (Japanese Patent Laid-Open No. 5-123845), but generally it takes a long time for vacuum suction in the cavity, and it is difficult to properly control the temperature in the sleeve. Therefore, a technique for shortening the time required for vacuum suction in the cavity and a method for appropriately controlling the temperature in the sleeve are desired.

  As a method for extracting air from the cavity, for example, as described in Patent Document 2, a method of performing through a joint between an upper mold and a lower mold, or Patent Document 3 (Japanese Utility Model Publication No. 62-56267). ), There is a method performed through a push pin. However, Patent Document 2 or 3 only describes the suction pressure reduction from the seam or the push pin in the cavity, and the inside of the cavity from the upper direction and the outer peripheral direction through the gap of the seam or the push pin or the porous plug. It is not considered to reduce the pressure by suction at a uniform pressure. In vacuum casting equipment, it is desirable to suction and reduce the inside of the cavity from the upper direction and the outer peripheral direction with a uniform pressure. If the suction pressure is not reduced with a uniform pressure, the molten metal is biased to a specific location in the cavity and the hot water is poor. There is a problem that defects such as these occur.

  Also, in order to stop the molten metal that is pushed up from the holding furnace to the vacuum mold through the stalk while the mold is uniformly evacuated, the holding furnace must be a closed furnace and the sealed furnace must also be evacuated. However, a large vacuum device is required to evacuate the closed furnace. When the closed furnace is large, it takes time to evacuate the closed furnace, and maintenance of the closed furnace takes considerable costs. It was.

JP 2014-104469 A JP-A-5-123845 Japanese Utility Model Publication No. 62-56267

In view of the above circumstances in the conventional low-pressure casting apparatus and vacuum casting apparatus, the present invention can use a vacuum pump and a bellows to suck and depressurize the inside of the cavity with a uniform pressure from the upper direction and the outer peripheral direction. It aims at providing the vacuum casting apparatus which can shorten the time concerning pressure reduction.

  In the present invention, in order to achieve the above object, the mold for a vacuum casting apparatus is provided with a gap 42 between the upper mold 29b and the lower mold 29a, and the air connected to the vacuum pump over the entire outer periphery of the gap 42. The passage 44 is provided so that the inside of the cavity 29c can be sucked and reduced with a uniform pressure from the outer peripheral direction. Further, the upper mold 29b of the vacuum casting mold is installed on the bellows 39 and the support plate 52 in the bellows 39, and protrudes from the upper mold 29b into the cavity 29c to demold the casting. And a gap 43 through which air communicates is provided between the outer peripheral surface of the push pin 38 and the tube 43 ′ through which the push pin passes, and the inside of the cavity can be sucked and reduced with a uniform pressure from above. It was.

That is, according to the first aspect of the present invention, the upper die 29b and the lower die 29a are vertically stacked to form a cavity 29c therein, and the inside of the cavity 29c is sucked and reduced by the vacuum pump 25, and the lower die 29a is placed under the lower die 29a. After the molten metal is filled into the cavity 29c from the stalk 1 'connected to the provided gate 29d, the upper die 29b and the lower die 29a are separated, and a plurality of push pins 38 protrude from the upper die 29b into the cavity 29c. Thus, the mold of the vacuum casting apparatus for removing the casting, which connects the vacuum pump 25 to the bellows 39 and a plurality of push pins 38 attached to the support plate 52 or 53 in the bellows 39, The air passage 4 is installed so as to penetrate the upper die 29b, and a gap 42 is provided between the upper die 29b and the lower die 29a, and is connected to the vacuum pump 25 over the entire outer periphery of the gap 42. 4, a gap 43 through which air communicates is provided between the outer peripheral surface of the push pin 38 and the pipe 43 ′ through which the push pin passes, and the gap 42 provided between the upper die 29 b and the lower die 29 a and the push pin A die for a vacuum casting apparatus in which the inside of the cavity 29c and the vacuum pump 25 or the bellows 39 are connected via a gap 43 provided between the outer peripheral surface of the pin 38 and the tube 43 ′ through which the push pin passes ; said bellows (39) within the bellows with support spring prevents contraction (39) slide mechanism (49) is a vacuum casting apparatus characterized that you have installed.

According to the second aspect of the present invention, the width of the gap 42 provided between the upper die 29b and the lower die 29a and the gap 43 provided between the outer peripheral surface of the push pin 38 and the pipe 43 ′ through which the push pin passes are set. The vacuum casting apparatus according to 1 of the present invention, wherein the vacuum casting apparatus is 0.05 mm to 0.2 mm.

3 of the present invention, further, 1 or according to the invention, characterized in that the bellows contraction prevention pin 46 to prevent the contraction of the bellows 39 during the depressurized suction is installed on the same support plate 52 and the slide mechanism 49 with the support spring 2. The vacuum casting apparatus according to 2 .

4 of the present invention, according to the third invention, characterized in that the support plate 53 of the push pins 38 to be attached to the upper surface of the bellows 39 is another plate and the support plate 52 for mounting the support spring slide mechanism 49 Vacuum casting equipment.

According to the vacuum casting apparatus 1 of the present invention, the gap 42 is provided between the upper die 29b and the lower die 29a, the air passage 44 connected to the vacuum pump is provided over the entire outer periphery of the gap 42, and the push pin 38 Since the gap 43 through which air communicates is provided between the outer peripheral surface and the pipe 43 ′ through which the push pin passes, the inside of the cavity 29c can be sucked and depressurized with a uniform pressure from the outer peripheral direction and the upward direction. The time required for decompression can be shortened.

According to the vacuum casting apparatus 2 of the present invention, the width of the gap 42 provided between the upper die 29b and the lower die 29a and the gap 43 provided on the outer peripheral surface of the push pin 38 is 0.05 mm to 0.2 mm. And preferably 0.05 mm to 0.1 mm, it is possible to prevent the molten metal from flowing out of the mold through the gap 42 and the gap 43, thereby causing a problem that burrs are generated. Absent.

Furthermore, according to the vacuum casting apparatus 1 of the present invention, the inside of the cavity can be sucked and depressurized with a uniform pressure from the outer peripheral direction and the upper direction, and a high-quality casting having no defects such as poor hot water can be obtained. In addition, since the time required for suction decompression in the cavity can be shortened, the casting cycle time of the casting can be shortened. Thereby, the production cost of a casting can be reduced. Further, the bellows 39 is crushed at the time of suction pressure reduction or at the time of casting extrusion, but since the slide mechanism 49 with a support spring is installed, the bellows 39 is not laterally displaced and only a certain length in the vertical direction. Since it is crushed and returned, the bellows, which is weak against lateral displacement, is not broken, and the vertical movement of the push pin 38 and the bellows shrinkage prevention pin 46 is smooth.

According to the vacuum casting apparatus 3 of the present invention, since the bellows shrinkage prevention pin 46 reaches the surface of the lower die 29a and the bellows 39 is installed so as not to be shrunk during vacuum, the bellows 39 is surely secured during the suction pressure reduction. It can be prevented from being crushed.

According to the vacuum casting apparatus 4 of the present invention, the support plate 53 of the push pin 38 is a plate different from the support plate 52 to which the slide mechanism 49 with a support spring is attached , so that the push pin corresponding to the shape of the mold is obtained. 38 can be easily adjusted. Because the push pin 38 needs to be finely adjusted in arrangement and length depending on the shape of the mold, for example, when changing the shape of the mold, the mounting plate such as the slide mechanism 49 with the support spring can be replaced as it is. This is because the adjustment can be performed by replacing only the mounting plate of the push pin 38.

It is sectional drawing of the state which accumulated the upper mold | type and the lower mold | type which show one Example of a vacuum casting apparatus. It is a partial expanded sectional view of the state where the upper model and the lower model were piled up which shows one example of a vacuum casting device. It is sectional drawing of the state which raised the upper mold | type which shows one Example of a vacuum casting apparatus, and isolate | separated the upper mold | type and the lower mold | type. It is a partial expanded sectional view of the state which raised the upper mold | type which shows one Example of a vacuum casting apparatus, and isolate | separated the upper mold | type and the lower mold | type. It is a partial expanded sectional view of the state where the upper model and lower model which piled up another example of a vacuum casting device were piled up.

  In the present invention, an upper die 29b and a lower die 29a are stacked one above the other to form a cavity 29c, and the gap between the upper and lower molds, the gap between the push pins and the porous plug is used as an evacuation flow path. A vacuum exhaust passage is connected to a bellows 39 having a push pin installed in the upper die 29b, and a vacuum pump is connected to the bellows 39, and the inside of the bellows 39 is brought into a decompressed state by being connected to the vacuum pump. The inside of the molten metal 12 rising from the furnace is stopped in the electromagnetic pump 14 ′ by the braking force of the electromagnetic pump 14 ′ connected to the gate provided in the lower part of the lower mold in order to reduce the pressure by suction. The vacuum casting apparatus for filling the cavity 29c to form a casting by weakening the braking force, and the inside of the cavity is vacuum pump 25 and bellows 39. A mold 27 that can be sucked and depressurized with a single pressure is used. While the mold 27 is held in vacuum, the molten metal 12 is braked (brake) by the electromagnetic pump 14 'to weaken the braking force, thereby directly forming a vacuum mold. This is an electromagnetic pump type vacuum casting apparatus for casting molten metal. DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in order based on the drawings.

  1 to 4 show an embodiment of a vacuum casting apparatus according to the present invention. FIGS. 1 and 2 show a state in which an upper mold 29b of a mold 27 is superposed on a lower mold 29a, and FIGS. The upper mold 29b of the mold 27 is shown separated from the lower mold 29a. This vacuum casting apparatus is an electromagnetic pump 14 ′ having a hot water induction inductor 14 in the duct 1 in a direction opposite to the direction in which the molten metal 12 is sucked by sucking and reducing the pressure in the cavity 29 c of the mold 27 by the vacuum pump 25. Applying thrust, once the molten metal 12 is held at a predetermined level 30 in the duct 1, the thrust of the electromagnetic pump 14 'is gradually weakened, and the mold 27 is filled with molten metal from the lower side through the stalk 1'. Is in the form of

  The lower end of the duct 1 of the electromagnetic pump 14 ′ is inserted into the molten metal 12 stored in the molten metal tank 11. Around the portion of the duct 1 above the liquid surface of the molten metal 12, a hot water supply inductor 14 is disposed in which a coil 16 is wound around a magnetic yoke 15. The yoke 15 is fitted on the outer peripheral side so as to surround a portion of the duct 1 above the liquid level of the molten metal 12, and a coil 16 constituting a three-phase coil is wound around the yoke 15. The hot water supply inductor 14 is provided with a cooler 10 and is cooled during driving.

  The hot water supply inductor 14 is driven by receiving power from a drive power supply 31 including an inverter. The drive power supply 31 energizes the hot water induction inductor 14 with the three-phase alternating current converted by the inverter, generates a moving magnetic field in the hot water induction inductor 14, and the duct 1 which is a conductor by electromagnetic induction of the moving magnetic field. Thrust is generated in the molten metal 12 inside.

  A stalk 1 ′ is closely connected to the upper end of the duct 1 via joints 5, 5 ′ such as flange joints. A flange 6 extends between the joints 5 and 5 'around one end portion of the protective tube 3 near the stalk 1', and a portion near the outer periphery of the flange 6 connects the duct 1 and the stalk 1 '. Between the joints 5 and 5 '. Thereby, the core 2 in the protective tube 3 is held so as to be positioned at the center of the duct 1. The flange 6 is provided with a plurality of arc-shaped passage holes 7 serving as passages for the molten metal 12. The stalk 1 'is elastically pressed against the duct 1 on the near side by a spring or the like (not shown). In this state, the sealability of the joints 5 and 5 'is ensured by the heat-resistant gasket inserted between the joints 5 and 5'.

  The duct 1 and the stalk 1 'are made of a heat-resistant and corrosion-resistant material such as ceramic, and the melting point of the molten metal 12 by the heaters 9 and 9' formed of a heat-retaining micro heater provided on the outer periphery thereof. The structure is heated to the above temperature to prevent the molten metal 12 from solidifying. In order to measure the liquid level of the molten metal 12 in the molten metal tank 11, a sensor 13 such as a liquid level sensor is provided, and thereby the liquid level of the molten metal 12 in the molten metal tank 11 is detected.

  On the other hand, a 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 stalk 1 ′, thereby detecting the liquid level in the stalk 1 ′. At least three columns 36 'and 36' are provided upright so as to surround the molten metal tank 11 and the hot water supply inductor 14, and support the base plate 33 on the stalk 1 '.

  In the present embodiment, a hole is opened at the center of the base plate 33, and ring plate-like insulating materials 35 and 35 ′ are installed around the hole, so that the base plate 33 is thermally insulated from the mold 27. Thermal insulation is provided via a material 35. For this reason, even if the mold 27 becomes high temperature with the molten metal 12, the base plate 33 can be kept at a low temperature. The stalk 1 'is also thermally insulated from the lower mold 29a by heat insulating materials 35 and 35'. This prevents the solidified layer from expanding due to the temperature drop of the molten metal 12 in the stalk 1 ′, and further prevents the temperature drop of the molten metal 12 in the duct 1 of the electromagnetic pump 14 ′ connected to the stalk 1 ′. It can prevent poor hot water.

  On the insulating material 35, a lower mold 29a of the mold 27 is mounted. A through hole-shaped gate 29d is provided at the center of the lower surface of the lower die 29a, and this gate 29d communicates with the upper end of the stalk 1 'through the central through hole of the insulating material 35. An upper mold 29b is overlaid on the lower mold 29a, and a mold 27 is formed by these upper and lower molds 29a and 29b. A cavity 29c for molding a casting is formed inside the mold 27, and this cavity 29c is connected to the upper end of the stalk 1 'through the gate 29d.

  Slide guides 34 and 34 are installed on the base plate 33, and a slide plate 37 can slide up and down along the slide guides 34 and 34. The slide plate 37 is pierced by slide guides 34 and 34 and an extruding member 45 for contracting a bellows 39 to be described later. Lifting drive mechanisms 36, 36 such as hydraulic cylinders are provided between the base plate 33 and the slide plate 37, and the slide plate 37 slides up and down along the slide guides 34, 34 by the operation of the lift driving mechanisms 36, 36. Is done. Further, the pushing member 45 slides up and down by the operation of an elevating drive mechanism (not shown), passes through the upper die base 40, and pushes down the support plate 52 on the upper surface of the bellows 39 to contract the bellows 39.

  A lower die base 40 ′ is fixed to the upper surface of the upper die 29 b, and the lower die base 40 ′ is connected to the upper die base 40 by support columns 41 and 41. The upper die base 40 is connected and held to the slide plate 37, and the upper die 29b is also raised and lowered as the slide plate 37 is raised and lowered. When the upper die 29b is lowered and the upper die 29b is overlapped with the lower die 29a fixed on the base plate 33, the cavity 29c of the die 27 is closed.

  A bellows 39 and a support plate 52 are installed between the lower die base 40 ′ and the upper die base 40. The bellows 39 is made of, for example, stainless steel, and has both stretchability and airtightness. The bellows 39 is connected by the vacuum pump 25 and the vacuum pipe 32 and the inside of the bellows 39 is sucked and decompressed. The vacuum pump 25 is driven by the driving power supply 26 and is directly connected to the mold 27 via the vacuum pipe 32 in addition to the bellows 39. A leak valve (not shown) for returning the inside of the vacuum pipe 32 to normal pressure is provided in the middle of the vacuum pipe 32. The inside of the bellows 39 is depressurized to about -100 kPa by a vacuum pump. The support plate 52 fixed to the upper surface in the bellows 39 is not fixed to the upper die base 40 and moves up and down as the bellows 39 contract. The support plate 52 is provided with a plurality of push pins 38. Although the shape of the mold 27 differs depending on the casting, the arrangement and number of the push pins 38 are determined according to the shape.

The push pin 38 penetrates the pipe 43 'penetrating the lower die base 40' and the upper die 29b.
The push pin 38 is configured so that its tip portion reaches the cavity 29c, but does not protrude into the cavity 29c when the upper die 29b and the lower die 29a are overlapped. In the present invention, a gap 43 through which air communicates is provided between the outer peripheral surface of the push pin 38 and the pipe 43 ′ through which the push pin passes, and the cavity 29 c is passed through the gap 43 to the inside of the bellows 39. Can be linked to. Thus, by providing the clearance 43 through which air communicates with the outer peripheral surfaces of the plurality of push pins 38, the inside of the cavity 29c can be sucked and reduced with a uniform pressure from above the mold 27 in a short time.

  The width of the gap 43 on the outer peripheral surface of the push pin 38 is 0.05 mm to 0.2 mm, preferably 0.05 mm to 0.1 mm, so that when the molten metal 12 is injected into the cavity 29 c, It is possible to prevent the molten metal 12 from flowing into the bellows 39. Thereby, the malfunction that a burr | flash comes out on the upper part of a casting does not arise.

  In addition, a plurality of slide mechanisms 49 with support springs are installed in the bellows 39 so that the bellows 39 is not laterally displaced and crushed when the vacuum pump 25 performs suction pressure reduction. The slide mechanism 49 with a support spring has an upper end fixed to the support plate 52 and a lower end fixed to the lower die base 40 ′. The slide mechanism 49 with a support spring is composed of a support spring mounting tube, a spring disposed therein, and a slide bar that pushes the spring from above, and the bellows 39 has a certain length when the cast is removed from the mold. The spring constant is such that it is crushed and is not crushed by its own weight of the bellows 39 or the support plate 52.

  Further, a plurality of bellows shrinkage prevention pins 46 are installed in the bellows 39 so that the bellows 39 is not crushed reliably during the suction pressure reduction. The bellows shrinkage prevention pin 46 has an upper end fixed to the support plate 52 and a lower end passing through the lower die base 40 'and the upper mold 29b and placed on a horizontal portion (outside the mold) of the lower mold 29a. The number of the support spring-equipped slide mechanisms 49 and the bellows shrinkage prevention pins 46 is, for example, four, each set at a position shifted by 45 °. With such an arrangement, the symmetry of the support structure is maintained, and the bellows 39 is not crushed even in a reduced pressure state (about −100 kPa) close to a vacuum.

  In this embodiment, the mounting plate for the push pin 38 and the mounting plate for the slide mechanism 49 with support spring and the bellows shrinkage prevention pin 46 are configured as a common support plate 52. However, the present invention is not limited to this configuration. The mounting plate of the pin 38 and the mounting plate of the slide mechanism 49 with support spring and the bellows shrinkage prevention pin 46 may be separated.

  When a casting is molded by this vacuum casting apparatus, first, the cavity 29c is formed by placing the upper mold 29b on the lower mold 29a. In the present invention, unlike the conventional mold, a gap 42 is provided between the upper mold 29b and the lower mold 29a, and an air passage 44 connected to the vacuum pump 25 is provided over the entire outer periphery of the gap 42. In this embodiment, as shown in FIGS. 2 and 4, the air passage 44 is directly connected to the vacuum pump 25 via the vacuum pipe 32, but may be connected to the vacuum pump 25 via the bellows 39. Good (not shown). If the upper mold 29b and the lower mold 29a are thermally deformed and the gap 42 between the upper mold 29b and the lower mold 29a cannot be made uniform, the gap 42 between the cavity 29c and the air passage 44 is unavoidably formed, and the Asahi flag Alternatively, the radial narrow bank-like convex portions may be left, or conversely, concave portions may be provided to finish the gaps as uniform as possible. In particular, when the coating agent applied to the inner surface of the cavity 29c must be applied also to the gap 42 side, a recess 42 may be provided to form the gap 42 in consideration of the thickness of the coating agent.

  Since the air passage 44 connected to the vacuum pump 25 is provided over the entire outer periphery of the gap 42, the air passage 44 uniformly sucks and depressurizes the cavity 29c by the vacuum pump 25, and thereby the inside of the cavity 29c from the outer peripheral direction. The suction pressure can be reduced with a uniform pressure. Further, since the suction and decompression can be simultaneously performed through the gap 43 provided on the outer periphery of the push pin 38, the inside of the cavity 29c can be sucked and decompressed with a uniform pressure from the outer peripheral direction and the upward direction. Thereby, the time required for the suction pressure reduction in the cavity can be shortened. A porous plug (not shown) having the same hole diameter as the gap can be provided near the portion where the casting becomes large and the push pin cannot be installed, so that the time required for suction and decompression in the cavity 29c can be shortened.

  The width of the gap 42 provided between the upper die 29b and the lower die 29a (indicated as g in FIG. 2) is provided between the outer peripheral surface of the push pin 38 and the tube 43 ′ through which the push pin passes. Similarly to the gap 43, the thickness is 0.05 mm to 0.2 mm, preferably 0.05 mm to 0.1 mm. Thereby, it is possible to prevent the molten metal 12 from flowing out of the mold from the gap 42, and no burrs are generated. When a porous plug (not shown) is provided, the hole is equivalent to the gap 42 and the gap 43, so that there is no need to spray the porous plug. In order to prevent outside air from entering the cavity 29c from the gap 42 between the upper mold 29b and the lower mold 29a, an O-ring 29e for airtight sealing is provided so as to surround the air passage 44.

  When the inside of the cavity 29c is sucked and reduced to about −100 kPa instantaneously by the vacuum pump 25, the molten metal 12 stored in the molten metal tank 11 under atmospheric pressure passes through the duct 1 and is pumped up vigorously. Even if 14 'is not used, the entire space is filled up to the inside of the cavity 29c. In the low pressure casting method, a good casting with less entrainment of gas and oxide can be made by slowly injecting molten metal 12 extruded from the stalk of the closed furnace by applying gas pressure to the closed furnace from the bottom of the mold. Similarly to the above, in the present invention, it is necessary to control the injection rate of the molten metal 12.

  Therefore, even if the cavity 29c is evacuated to the electromagnetic pump 14 'before that, the molten metal 12 is placed in the duct 1 of the electromagnetic pump 14' so that the molten metal is not injected uncontrolled into the reduced-pressure vacuum mold. Energization is performed so that a braking force is generated in a direction opposite to the injection direction of the molten metal 12. At the same time as the cavity 29c is evacuated, the molten metal rises in the duct 1, but instantaneously a braking force is generated in the molten metal 12, the molten metal 12 is braked in the duct 1, and the braking force is adjusted to adjust the stalk. The molten metal 12 is held at a predetermined level 30 of 1 ′, and the braking force is weakened at a predetermined speed to fill the cavity 29c with the molten metal 12. In the present invention, the braking force of the electromagnetic pump 14 'is used to temporarily hold the cavity 29c in the stalk 1' using the braking force of the electromagnetic pump 14 'so as to function like an electromagnetic valve.

  When the molten metal 12 is filled into the cavity 29c of the mold 27, the flow of the molten metal 12 may be uniformly divided using a diverter 55 as shown in FIGS. The shunt 55 includes a heater 47, a thermocouple 48, a power source 50, and a measuring device 51. By using the diverter 55, there is an advantage that the casting can be easily separated and cut at the gate 29d of the mold 27. In addition, there is an advantage that the temperature of the molten metal 12 can be prevented from being lowered by setting the current divider 55 to a temperature higher than that of the mold 27.

  After filling the cavity 29c with the molten metal 12, as shown in FIGS. 3 and 4, when the slide plate 37 is raised and the upper die 29b is raised, the upper die 29b is separated from the lower die 29a, and the die 27 cavities 29c are opened. The cast 59 molded at this time is attached to the upper mold 29b. When the upper die 29b is further raised, the support plate 52 comes into contact with the pushing member 45, the bellows 39 and the support plate 52 are pushed, and the tips of the plurality of push pins 38 installed on the support plate 52 enter the cavity 29c. The molded casting 59 is separated from the upper mold 29b. Before the casting 59 is separated from the upper mold 29b, a receiving tray (not shown) or the like comes under the casting 59 so that the casting 59 to be separated can be received.

  At this time, the bellows 39 is crushed by a certain length according to the slide mechanism 49 with a support spring without lateral displacement. In this way, the bellows 39 is crushed to a certain length, and after the molded cast 59 is separated from the upper mold 29b, the slide plate 37 is lowered, and the tip of the push pin 38 and the bellows contraction preventing pin 46 Even if the tip portion does not hang downward from the upper die 29b and temporarily hangs down, it is returned to the upper die 29b by the slide mechanism 49 with a support spring.

  The molded casting 59 is taken out into a receiving tray or the like (not shown) to complete one casting process. Thereafter, the upper mold 29b is overlaid on the lower mold 29a, the mold 27 is assembled, and molding is repeated. 3 and 4 show a state in which the casting 59 is pushed out of the upper die 29b and dropped onto the lower die 29a in order to make the casting 59 easy to understand.

FIG. 5 is a partial enlarged cross-sectional view showing a state in which an upper die and a lower die are overlapped, showing another embodiment of the vacuum casting apparatus of the present invention. The difference between the above embodiment and the present embodiment is that the support plate 53 of the push pin 38 in the bellows 39 of the vacuum casting apparatus is different from the support plate 52 of the slide mechanism 49 with support spring and the bellows shrinkage prevention pin 46. It is the point which made it. As shown in FIG. 5, the push pin 38 is attached to the support plate 53, and the slide mechanism 49 with a support spring and the bellows shrinkage prevention pin 46 are attached to the support plate 52 above the support plate 53.

  Since the length of the push pin 38 needs to be finely adjusted depending on the shape of the mold, the support plate 52 to which the push pin 38 is attached is replaced with the support plate 53 to which the slide mechanism 49 with a support spring and the bellows shrinkage prevention pin 46 are attached. If it is configured separately, the adjustment becomes easy. For example, when changing the shape of the mold, the mounting plate such as the slide mechanism 49 with the support spring is not replaced as it is, and the adjustment can be performed by replacing only the mounting plate of the push pin 38. However, if the mounting plate of the push pin 38 and the other mounting plate are configured as different support plates as described above, there is a disadvantage that the overall dimensional deviation may occur because the dimensional accuracy is different.

In the vacuum casting apparatus using the electromagnetic pump 14 'as an electromagnetic valve to evacuate the inside of the mold described above, a gap 42 is provided between the upper mold 29b and the lower mold 29a, and the entire outer periphery thereof is provided. An air passage 44 connected to the vacuum pump is provided, and a gap 43 through which air communicates is provided between the outer peripheral surface of the push pin 38 and the tube 43 'through which the push pin passes, so that the outer periphery of the cavity is provided. It is possible to suck and depressurize with a uniform pressure from the direction and upward, and since there is no gas in the cavity 29c in the mold, a high-quality casting can be produced. In addition, since there is no gas trapped in the cavity during casting, the injection rate into the mold can be increased, and as a benefit, the mold temperature can be lowered, so that the casting cycle time can be shortened and the production cost of the casting can be reduced. Can be reduced.

  An electromagnetic pump vacuum casting apparatus according to the present invention is a vacuum casting apparatus having a structure in which a mold is assembled or removed by moving an upper mold up and down by a slide mechanism. Since suction can be reduced in time, and there is no gas in the cavity, a high-quality casting can be produced, so that it can be used in fields requiring high quality.

1 'Stoke 12 Molten metal 25 Vacuum pump 27 Mold 29a Mold lower mold 29b Mold upper mold 29c Mold cavity 29d Mold gate 33 Base plate 34 Slide guide 38 Push pin 39 Bellows 42, 43 Gap 43 'Tube through which the push pin passes 46 Bellows shrinkage prevention pin 49 Slide mechanism 52 with support spring Support plate

Claims (4)

The upper die (29b) and the lower die (29a) are stacked one above the other to form a cavity (29c) therein, and the inside of the cavity (29c) is sucked and reduced by the vacuum pump (25), and the lower die ( After filling the cavity (29c) with molten metal (12) from the stalk (1 ') connected to the gate (29d) provided at the lower part of 29a), the upper mold (29b) and the lower mold (29a) are Separately, a plurality of push pins (38) are protruded from the upper mold (29b) into the cavity (29c), thereby demolding the casting, and the vacuum pump (25 ) Are connected to the inside of the bellows (39), and a plurality of push pins (38) attached to the support plate (52) or (53) in the bellows (39) are installed so as to penetrate the upper mold (29b). And the upper mold (29b) A clearance (42) is provided between the lower die (29a), an air passage (44) connected to the vacuum pump (25) is provided over the entire outer periphery of the clearance (42), and an outer periphery of the push pin (38). A gap (43) through which air communicates is provided between the surface and the pipe (43 ') through which the push pin passes, and the gap (42) provided between the upper mold (29b) and the lower mold (29a). And through the gap (43) provided between the outer peripheral surface of the push pin (38) and the pipe (43 ') through which the push pin passes, the inside of the cavity (29c) and the vacuum pump (25) or with a vacuum casting apparatus die coupled with said bellows (39), Rukoto the inside bellows (39), said bellows (39) supporting a spring-slide mechanism for preventing contraction (49) has not been installed Vacuum casting equipment characterized by The gap (42) provided between the upper die (29b) and the lower die (29a) and the outer peripheral surface of the push pin (38) and the pipe (43 ′) through which the push pin passes are provided. The vacuum casting apparatus according to claim 1, wherein the gap (43) has a width of 0.05 mm to 0.2 mm. In the bellows ( 39), a bellows shrinkage prevention pin (46) for preventing the bellows (39) from shrinking during suction pressure reduction is installed on the same support plate (52) as the slide mechanism with support spring (49). The vacuum casting apparatus according to claim 1 or 2, wherein the apparatus is a vacuum casting apparatus. The support plate (53) of the push pin (38) attached to the upper surface in the bellows (39) is a plate different from the support plate (52) to which the slide mechanism with support spring (49) is attached. The vacuum casting apparatus according to claim 3.