Casting device

Abstract

To provide a casting apparatus capable of suppressing a production cost with a simple constitution and improving the precision of a casting quality by making the shape of a molten metal made to flow into a sprue of a mold certain every time to suppress a raw material cost.SOLUTION: A casting apparatus 1 comprises: a chamber 3 having an inside decompressed by a decompression device; a rolling support part 41 fixed to the chamber 3; a crucible 42 rotatably provided with respect to the rolling support part 41; a mold 44 fixed so that relative displacement is impossible with respect to the crucible 42; a stopper 53 regulating the rolling displacement of the crucible 42; and an electrode torch 64 executing arc discharge with respect to a metal provided at the crucible 42. The metal is melted by the arc discharge of the electrode torch 64 in a state where the rolling displacement of the crucible 42 is regulated by the stopper 53, and the rolling displacement regulation of the crucible 42 by the stopper 53 is released, therefore the crucible 42 and the mold 44 are rolled off to flow the molten metal into the mold 44.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a casting apparatus that performs metal casting with a reduced internal pressure.

Background Art

[0002] Conventionally, techniques for melting and casting metals such as titanium have been known (see, for example, Patent Document 1 and Patent Document 2). Patent Document 1 and Patent Document 2 disclose a casting apparatus configured to pour molten metal melted in a crucible into a mold.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the casting apparatus described in Patent Document 1, the configuration is such that the crucible is tilted to pour the molten metal into the mold. In this case, since the relative positions (distance and angle) between the crucible and the mold change when pouring the molten metal into the mold, the shape of the molten metal flowing into the gate of the mold is not constant each time, which has been a cause of variations in casting quality. Also, since a large amount of molten metal is required to maintain casting quality, it has been a factor in increasing raw material costs.

[0005] In the casting apparatus described in Patent Document 2, the crucible and the mold are integrally configured and rotated to pour the molten metal into the mold. In this case, since a configuration for rotating the crucible and the mold is required, the configuration of the casting apparatus becomes large-scale, which has been a factor in increasing manufacturing costs.

[0006] Therefore, an object of the present disclosure is to provide a casting apparatus that can suppress manufacturing costs with a simple configuration, and can improve the accuracy of casting quality and suppress raw material costs by making the shape of the molten metal flowing into the sprue of the mold constant each time.

Means for Solving the Problems

[0007] Hereinafter, means for solving the above problems will be described.

[0008] The casting apparatus according to the present invention includes a chamber whose interior is depressurized by a decompression device, a rotation support portion fixed to the inner surface of the upper part in the chamber, a crucible rotatably provided with respect to the rotation support portion, and a mold fixed to the outer side in the radial direction of the rotation axis of the crucible so as not to be relatively displaced with respect to the crucible, and regulating the rotational displacement of the crucible with respect to the rotation support portion Regulating unit and an electrode torch that performs arc discharge on the metal disposed in the crucible. The regulating unit includes a cylinder, a rod that extends in and out of the cylinder, and a stopper provided at the tip of the rod that can move in and out of the internal space of the chamber. On the crucible, a surface to be regulated is formed on the side facing the stopper. When the rod extends from the cylinder, the end face on the advancing side of the stopper abuts against the surface to be regulated of the crucible, thereby restricting the rotational displacement of the crucible with respect to the rotation support portion. Metal is placed in the crucible, and the stopper bringing the end face in [description] into contact with the surface to be regulated With the rotational displacement of the crucible restricted, the metal is melted by the arc discharge of the electrode torch, and the stopper separating the end face in [description] from the surface to be regulated By releasing the regulation of the rotational displacement of the crucible, the crucible and the mold rotate and fall, and the molten metal is poured into the mold.

[0009] Further, in the casting apparatus according to the present invention, it is preferable that a deceleration unit for decelerating the rotationally falling mold is provided.

[0010] Further, in the casting apparatus according to the present invention, a cushion cylinder is provided at the lower part of the chamber as the deceleration unit, and the cushion cylinder is preferably arranged in the circumferential direction of the rotation axis.

[0011] Further, in the casting apparatus according to the present invention, it is preferable that a spacer is arranged inside the chamber on the outside of the rotation locus of the mold.

Effects of the Invention

[0012] According to the casting device of the present invention, with a simple configuration, the manufacturing cost can be suppressed, and by making the shape of the molten metal flowing into the sprue of the mold constant each time, the accuracy of the casting quality can be improved and the raw material cost can be suppressed.

[0013] Also, according to the casting device of the present invention, by decelerating the rotating and falling mold, the influence on the casting quality can be suppressed.

[0014] Also, according to the casting device of the present invention, a deceleration part can be provided with a simple configuration by a cushion cylinder.

[0015] Also, according to the casting device of the present invention, by reducing the air in the chamber, the decompression in the chamber can be performed in a short time, and the instantaneous pressure increase during pressurization can be performed in a short time.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiment for Carrying out the Invention

[0017] [Casting Device 1] Hereinafter, with reference to FIGS. 1 to 7, a casting device 1 according to an embodiment of the present invention will be described. The casting device 1 is used when casting a casting crown made of pure titanium or a denture base made of a titanium alloy (such as Ti-6Al-4V).

[0018] As shown in FIGS. 1 to 3, the casting device 1 according to the present embodiment includes a main body portion 2 that is a housing, and a chamber 3 assembled to the main body portion 2. Hereinafter, the surface of the casting device 1 on the side where the chamber 3 is assembled (the surface shown in FIG. 2) will be described as the front surface of the casting device 1.

[0019] An operation portion 2a protrudes and is formed on the upper rear portion of the main body portion 2. An operation panel 21 is formed on the front surface of the operation portion 2a. The operation panel 21 is provided with a touch panel 22, an arc ammeter 23, an output adjuster 24, and various operation buttons 25. The user of the casting device 1 controls the operation of the casting device 1 by operating the operation panel 21 via a control device (not shown) housed inside the main body portion 2.

[0020] An opening / closing plate 2b is provided on the left side surface of the main body portion 2 (the surface shown in FIG. 3). An inspection window 2c is provided on the opening / closing plate 2b so as to be openable and closable. Four leg members 2d are provided on the lower surface of the main body portion 2. A pressure gauge 2e and a pressure tank connection gauge 2f are provided at the lower front portion of the main body portion 2.

[0021] A hook support member 2g is provided on the right side portion of the main body portion 2 so as to be rotatable about a rotation shaft 2h. A tightening hook 2j that is rotatable by a handle 2i is provided on the hook support member 2g. When the user rotates the handle 2i, the lid member 32 of the chamber 3 is tightened by the tightening hook 2j.

[0022] Chamber 3 includes a chamber body 31 formed in a bottomed rectangular tube shape, and a lid member 32 that can be opened and closed with respect to the chamber body 31 via a hinge 33. A regulating portion 5 and a speed reducing portion 7 are assembled to the left side surface of the chamber body 31. A viewing window 34 that allows visual recognition of the inside of the chamber 3 is provided on the upper surface of the lid member 32. Further, a strain gauge 35 is provided to the right of the viewing window 34.

[0023] In the casting apparatus 1 according to the present embodiment, the chamber 3 is connected to a decompression device including a vacuum pump (not shown). The chamber 3 is configured to be decompressible by this decompression device. Further, the chamber 3 is connected to an argon gas supply device and a pressure tank (not shown). With these, argon gas can be enclosed in the chamber 3 through a gas supply portion 8 provided in the chamber body 31, and further, the inside of the chamber 3 can be pressurized. The gas supply portion 8 includes a gas supply member 81 provided on the right inner side surface of the chamber body 31, and argon gas is supplied from a gas supply port 81a opened in the gas supply member 81.

[0024] Inside the chamber 3, a crucible 42 and a mold 44 are assembled via rotation support portions 41·41. Specifically, on the upper part of the left inner side surface of the chamber body 31, the rotation support portions 41·41, which are two plate-like portions, are fixed via a fixing plate 41a. The rotation support portions 41·41 are provided so as to extend toward the inside (right side) of the chamber 3. Groove portions 41b are formed on the upper sides of the respective rotation support portions 41.

[0025] A copper crucible 42 is rotatably assembled to the rotation support portions 41·41. A rotation shaft 42a extending in the front-rear direction is formed in the crucible 42. Then, by inserting this rotation shaft 42a into the groove portion 41b of the rotation support portion 41, the crucible 42 is made rotatable with respect to the rotation support portions 41·41. When using the casting apparatus 1, a metal ingot Mi is placed on the upper surface of the crucible 42. Note that the crucible 42 can also be formed of a metal other than copper, or other materials such as carbon or ceramic.

[0026] On the radially outer side (right side in this embodiment) of the rotation axis 42a in the vicinity of the crucible 42, the mold 44 is fixed via a connecting member 43 so as not to be relatively displaced with respect to the crucible 42. A casting chamber 44a is formed in the mold 44.

[0027] The connecting member 43 is composed of connecting plates 43a, 43a, connecting rods 43b, 43b, a mold support portion 43c, a lower fixture 43d, an upper fixture 43e, fastening bolts 43f, and the like. The connecting plates 43a, 43a are fixed to both the front and rear surfaces of the crucible 42. Connecting rods 43b extending rightward are fixed from each of the connecting plates 43a. A mold support portion 43c is bridged across the middle portions of the two connecting rods 43b, 43b.

[0028] The tip ends of the two connecting rods 43b, 43b are connected by a lower fixture 43d. An upper fixture 43e is assembled to the lower fixture 43d via a fastening bolt 43f. The user of the casting apparatus 1 tightens the fastening bolt 43f with the mold 44 placed on the mold support portion 43c. Thereby, the mold 44 is clamped by the upper fixture 43e and the lower fixture 43d, and the mold 44 is fixed in the vicinity of the crucible 42 via the connecting member 43.

[0029] As described above, when the mold 44 is fixed to the crucible 42, the mold 44 is rotatably supported with respect to the rotation support portions 41, 41 integrally with the crucible 42. In the casting apparatus 1, as shown in FIGS. 4 and 6, a spacer 36 is disposed outside the rotation locus of the mold 44 inside the chamber body 31.

[0030] In the casting apparatus 1 according to the present embodiment, the rotation displacement of the crucible 42 and the mold 44 is restricted by a restricting portion 5. The restricting portion 5 is fixed to the upper left outer surface of the chamber body 31. The restricting portion 5 is composed of an insulating flange portion 50, a cylinder 51, a rod 52, a stopper 53, and the like.

[0031] The cylinder 51 in the regulating unit 5 is fixed to the chamber 3 via an insulating flange portion 50 fixed to the left outer surface of the chamber body 31. A rod 52 extends from the cylinder 51 so as to be able to advance and retract. At the right end portion of the rod 52, a stopper 53 that can advance and retract into the internal space of the chamber 3 is provided through a hole 31a formed in the chamber body 31. A positive electrode 53a is formed at the tip of the stopper 53, and the positive electrode 53a is electrically connected to a power supply device (not shown) via the stopper 53 and the like.

[0032] When the rod 52 extends from the cylinder 51 and the stopper 53 abuts against the crucible 42, the rotational displacement of the crucible 42 with respect to the rotation support portions 41·41 is restricted. On the other hand, when the rod 52 retracts into the cylinder 51 and the stopper 53 separates from the crucible 42, the restriction on the rotational displacement of the crucible 42 with respect to the rotation support portions 41·41 is released.

[0033] As shown in FIGS. 4 and 5, a discharge unit 6 is provided above the crucible 42. The discharge unit 6 includes a power cord C, a negative electrode 61, an electrode table 62, a gripping portion 63, and an electrode torch 64, each of which is electrically connected to a power supply device (not shown).

[0034] As shown in FIG. 5, the negative electrode 61 is connected to the power cord C and fixed to the rear surface of the chamber body 31. An electrode torch 64, which is a tungsten rod, is electrically connected to the negative electrode 61 via the electrode table 62 and the gripping portion 63. The electrode torch 64 is arranged such that its lower end portion is positioned above the metal ingot Mi when the metal ingot Mi is placed on the crucible 42. When casting is performed with the casting apparatus 1, the electrode torch 64 arranged on the crucible 42 is configured to perform arc discharge on the metal ingot Mi.

[0035] In the casting apparatus 1 according to the present embodiment, the rotation of the crucible 42 and the mold 44 is decelerated by a deceleration unit 7. The deceleration unit 7 is fixed to the left outer surface at the lower part of the chamber body 31. The deceleration unit 7 is composed of a cushion cylinder 71, a cushion rod 72, a contact portion 73, a vibration-proof plate 74, and the like.

[0036] The cushion cylinder 71 in the speed reduction unit 7 is fixed to the left outer surface of the chamber body 31. A cushion rod 72 extends from the cushion cylinder 71 so as to be able to advance and retract. The cushion cylinder 71 is arranged in the circumferential direction of the rotation axis 42a of the crucible 42 (the tangential direction of the circle centered on the rotation axis 42a). The cushion rod 72 is inserted into the chamber body 31. A contact portion 73 is provided at the right end of the cushion rod 72. The displacement of the contact portion 73 in the vertical direction is restricted by the anti-vibration plate 74.

[0037] [Casting method] Next, with reference to FIGS. 7 to 11, the procedure for performing casting using the casting apparatus 1 according to the present embodiment will be described. First, as shown in FIG. 7, in the casting apparatus 1, the rod 52 is extended from the cylinder 51, and the stopper 53 is brought into contact with the crucible 42. Thereby, the rotational displacement of the crucible 42 with respect to the rotation support portions 41·41 is restricted, and the crucible 42 is fixed so that the upper surface of the crucible 42 becomes horizontal.

[0038] Then, with the metal ingot Mi placed on the upper surface of the crucible 42, the lid member 32 is closed. Thereafter, the decompression device is operated to decompress the inside of the chamber 3 to near vacuum by the vacuum pump, and an inert gas is introduced into the chamber 3 by the argon gas supply device.

[0039] Furthermore, as shown in FIG. 8, when the power supply device applies a voltage to the electrode torch 64 and the positive electrode 53a, arc discharge is performed from the electrode torch 64 to the metal ingot Mi disposed in the crucible 42. The metal ingot Mi in the crucible 42 is melted by the arc discharge to become molten metal Mm. In this way, by melting the metal ingot Mi in a reduced-pressure inert gas atmosphere, it is possible to prevent the molten metal Mm from reacting with oxygen, nitrogen, etc. in the air in the chamber 3.

[0040] Then, as shown in FIG. 9, the rod 52 is retracted into the cylinder 51 to separate the stopper 53 from the crucible 42. As a result, the rotational displacement regulation of the crucible 42 with respect to the rotation support portions 41·41 is released, and the crucible 42 and the mold 44 rotate and fall. Due to the rotation of the crucible 42, the molten metal Mm is poured into the casting chamber 44a of the mold 44, and a casting (cast crown) is formed inside the casting chamber 44a. At this time, the inside of the chamber 3 is pressurized by the compressed inert gas stored in the pressure tank.

[0041] The rotationally falling mold 44 abuts against the abutting portion 73 in the deceleration portion 7 as shown in FIG. 10, and decelerates while pushing the cushion rod 72 into the cushion cylinder 71. In other words, in the deceleration portion 7 of the casting apparatus 1, the cushion cylinder 71 absorbs the kinetic energy of the mold 44 via the abutting portion 73 and the cushion rod 72, thereby decelerating the rotationally falling mold 44. As shown in FIG. 11, the mold 44 stops in a state where the cushion rod 72 is pushed in.

[0042] As described above, in the casting apparatus 1 according to the present embodiment, the metal ingot Mi is melted by the arc discharge of the electrode torch 64 while the rotational displacement of the crucible 42 is regulated by the stopper 53. Then, by releasing the regulation of the rotational displacement of the crucible 42 by the stopper 53, the crucible 42 and the mold 44 rotate and fall, and the molten metal Mm is poured into the casting chamber of the mold 44.

[0043] According to the casting apparatus 1 according to the present embodiment, the mold 44 is fixed to the crucible 42 via the connecting member 43 so as not to be relatively displaceable. For this reason, when pouring the molten metal Mm into the mold 44, the relative positions (distance and angle) between the crucible 42 and the mold 44 can be made invariable. That is, since the shape of the molten metal Mm flowing into the sprue of the mold 44 can be kept constant every time, the casting quality can be maintained at a high level. In addition, since the casting quality can be maintained even with less molten metal Mm compared to the prior art, it is possible to suppress the raw material cost.

[0044] Moreover, according to the casting apparatus 1 according to the present embodiment, the crucible 42 and the mold 44 are configured to be rotated and dropped. Thereby, it is not necessary to provide a configuration such as a rotation mechanism for rotating the crucible 42 and the mold 44. That is, it is possible to suppress the manufacturing cost of the casting apparatus 1 with a simple configuration.

[0045] In the casting apparatus 1 according to the present embodiment, a deceleration unit 7 for decelerating the rotationally dropped mold 44 is provided. Thereby, since the impact applied to the rotationally dropped mold 44 can be reduced, the influence on the casting quality can be suppressed.

[0046] In the casting apparatus 1, a cushion cylinder 71 is provided as the deceleration unit 7, and the cushion cylinder 71 is arranged in the circumferential direction of the rotation axis 42a of the crucible 42. Thus, in the casting apparatus 1, it is possible to provide the deceleration unit 7 with a simple configuration by the cushion cylinder 71.

[0047] In the casting apparatus 1 according to the present embodiment, a spacer 36 is arranged inside the chamber 3 outside the rotation locus of the mold 44. Thereby, since the volume (amount of air) inside the chamber 3 can be reduced, it is possible to reduce the pressure inside the chamber 3 by the pressure reducing device in a short time. Further, since the volume inside the chamber 3 can be reduced, the instantaneous pressure increase during pressurization can be performed in a short time, and the specified pressure can be quickly reached.

Explanation of reference numerals

[0048] 1 Casting apparatus 2 Main body 2a Operation unit 2b Opening / closing plate 2c Inspection window 2d Leg member 2e Pressurization pressure gauge 2f Pressurization tank connection gauge 2g Hook support member 2h Rotation axis 2i Handle 2j Tightening hook 3 Chamber 5 Regulation unit 6 Discharge unit 7 Deceleration unit 8 Gas supply unit 21 Operation panel 22 Touch panel 23 Arc ammeter 24 Output regulator 25 Operation button 31 Chamber body 31a Hole part 32 Cover member 33 Hinge 34 Peephole 35 Connecting meter 36 Spacer 41 Rotation support part 41a Fixed plate 41b Groove part 42 Crucible 42a Rotation shaft 43 Connecting member 43a Connecting plate 43b Connecting rod 43c Mold support part 43d Lower fixture 43e Upper fixture 43f Fastening bolt 44 Mold 44a Casting chamber 50 Insulating flange part 51 Cylinder 52 Rod 53 Stopper 53a Positive electrode 54 Insulating plate 61 Negative electrode 62 Electrode base 63 Gripping part 64 Electrode torch 71 Cushion cylinder 72 Cushion rod 73 Contact part 74 Anti-vibration plate 81 Gas supply member 81a Gas supply port Mi Metal ingot Mm Molten metal C Power cord

Claims

1. A chamber whose interior is evacuated by a vacuum device, A rotation support portion fixed to the inner surface of the upper part in the chamber, A crucible rotatably provided with respect to the rotation support portion, A mold fixed to the outer side in the radial direction of the rotation axis of the crucible so as not to be relatively displaced with respect to the crucible, A restricting portion for restricting the rotational displacement of the crucible with respect to the rotation support portion, An electrode torch for performing arc discharge on the metal disposed in the crucible, and comprising: The restricting portion includes a cylinder, a rod that extends in and out of the cylinder, and a stopper provided at the tip of the rod and capable of moving in and out of the internal space of the chamber, A surface to be restricted is formed on the crucible on the side facing the stopper, When the rod extends from the cylinder and the end face on the advancing side of the stopper abuts against the surface to be restricted of the crucible, the rotational displacement of the crucible with respect to the rotation support portion is restricted, Metal is placed in the crucible, and the metal is melted by the arc discharge of the electrode torch in a state where the end face of the stopper is brought into contact with the surface to be restricted to restrict the rotational displacement of the crucible, A casting apparatus in which the end face of the stopper is separated from the surface to be restricted to release the restriction on the rotational displacement of the crucible, whereby the crucible and the mold rotate and fall, and the molten metal is poured into the mold.

2. The casting apparatus according to claim 1, further comprising a deceleration unit for decelerating the rotating and falling mold.

3. A cushion cylinder is provided at the lower part of the chamber as the deceleration unit, The casting apparatus according to claim 2, wherein the cushion cylinder is arranged in the circumferential direction of the rotation axis.

4. The casting apparatus according to any one of claims 1 to 3, wherein a spacer is arranged inside the chamber outside the rotation locus of the mold.

Images