Centrifugal casting system for manufacturing refrigeration-compressor bearing

Abstract

To provide a centrifugal casting system for manufacturing a refrigeration-compressor bearing allowed to prevent a casting from lowering in quality, by preventing the phenomenon that a melt is cooled into solidification by external air in a process of transferring the melt ladle accommodating the melt to a melt injection port of a casting mold and injecting it.SOLUTION: A centrifugal casting system may include a casting mold formed with a melt injection port through which melt is to be injected, a mold driving unit that rotates the casting mold, and a melt feed unit including a melt ladle that is for reserving a melt to be injected into the casting mold and provided at one-side upper end with a melt discharge port through which the melt is to be discharged, a ladle cover that opens / closes an upper face of the melt ladle, an auxiliary cover that is movably provided at one side of the ladle cover and opens the melt discharge port when the melt ladle is inclined toward one side to discharge the melt through the melt discharge port and a ladle transfer unit that is for transferring the melt ladle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a centrifugal casting system for manufacturing a bearing for a refrigeration compressor by a centrifugal casting method. More specifically, the present invention relates to a centrifugal casting system that injects molten metal into a casting mold, rotates it at high speed, and manufactures a casting of a bearing for a refrigeration compressor by centrifugal force.

Background Art

[0002] Generally, centrifugal casting is a method of injecting molten metal into a casting mold that rotates at a high speed of 300 RPM, obtaining a casting with a dense structure by centrifugal force, and manufacturing a casting with excellent characteristics by separating impurities due to the specific gravity difference.

[0003] The above horizontal centrifugal casting machine is mainly used for manufacturing mechanical elements that fix a rotating shaft at a certain position, such as a double pipe for transportation or a sliding bearing with an abrasion-resistant coating material formed inside, and rotate the shaft while supporting the weight of the shaft and the load applied to the shaft.

[0004] As a typical example of a centrifugal casting machine, there is a horizontal centrifugal casting device for forming a cylindrical body disclosed in Korean Registered Patent No. 10-1566706. This device has an injection port formed at one end for injecting molten metal, a hollow cylindrical mold that rotates around a horizontal axis, a driving unit that rotates the cylindrical mold around a horizontal axis, a support unit that rotatably supports the cylindrical mold, is formed in a cylindrical shape with an open upper end, and is formed such that an injection pipe that enters the inside of the injection port extends from one side, and a sprue that injects the molten metal supplied by a ladle into the inner space of the cylindrical mold through the injection pipe, and an injection auxiliary torch that is provided at the upper end of the sprue, sprays a flame downward toward the inner space of the sprue to heat the molten metal in the sprue, and pressurizes the injection pipe side.

[0005] The above-mentioned horizontal centrifugal casting device of the registered patent heats and pressurizes the molten metal in the tundish vessel using a torch, providing the advantage that even if the inner diameter of the injection pipe is small, the molten metal can be pushed toward the injection pipe side and injected into the casting mold quickly and smoothly.

[0006] However, the method of heating the molten metal in the tundish vessel by providing a torch has the problem that there is a risk of the molten metal splashing out due to the torch flame and causing a safety accident, and it is difficult to actually apply it because of the difficulty of installation and operation.

[0007] In addition, the conventional horizontal centrifugal casting device cools the casting mold by spraying cooling water at the completion of centrifugal casting or during the centrifugal casting process. However, if the cooling water is not sprayed uniformly on the casting mold, it is difficult to ensure the quality of the cast product, and there is also a problem that the amount of cooling water used increases.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention is for solving the above problems, and the object of the present invention is to prevent the phenomenon that the molten metal is cooled and solidified by external air during the process of transferring and injecting the molten metal ladle containing the molten metal into the molten metal inlet of the casting mold, so as to provide a centrifugal casting system for manufacturing a bearing for a refrigeration compressor that can prevent the deterioration of the quality of the casting product.

[0010] Another object of the present invention is to provide a centrifugal casting system for manufacturing a bearing for a refrigeration compressor, which can quickly and uniformly cool the casting mold immediately after the completion of centrifugal casting or during the centrifugal casting process, and can reduce the amount of cooling water used.

Means for Solving the Problems

[0011] A centrifugal casting system for manufacturing a bearing for a refrigeration compressor according to the present invention for achieving the above object includes a casting mold in which a molten metal inlet for injecting molten metal is formed, a mold driving unit for rotating the casting mold, a molten metal ladle for storing the molten metal to be injected into the casting mold and provided with a molten metal discharge port through which the molten metal is discharged on one side of the upper end, a ladle cover for opening and closing the upper surface of the molten metal ladle, an auxiliary cover movably provided on one side of the ladle cover and opening the molten metal discharge port when the molten metal ladle is inclined to one side so as to discharge the molten metal through the molten metal discharge port, and a molten metal supply unit including a ladle transfer unit for transferring the molten metal ladle.

[0012] The auxiliary cover is provided to rotate about a hinge shaft on one side of the ladle cover, and the upper surface of the auxiliary cover is connected to the structure of the ladle transfer unit by a link bar, and when the molten metal ladle is inclined to one side, the auxiliary cover may rotate about the hinge shaft by the link bar to open the molten metal discharge port.

[0013] The centrifugal casting system of the present invention may further include a hot air injection nozzle that injects hot air toward the molten metal discharge port when the auxiliary cover is opened at the end of the auxiliary cover, and a hot air supplier that heats air and supplies it to the hot air injection nozzle.

[0014] A heat reflective member in which a heat reflective film is laminated on the outer surface of a heat insulating material may be attached to the lower surface of the ladle cover.

[0015] The centrifugal casting system according to another embodiment of the present invention includes a cooling water header that is provided along the length direction of the casting mold above the casting mold and supplies cooling water, and a plurality of cooling water nozzles that are arranged along the length direction of the cooling water header and inject cooling water toward the casting mold. The plurality of cooling water nozzles may be arranged so as to be displaced with a predetermined phase difference in the circumferential direction so as to inject cooling water at different angles in the circumferential direction.

[0016] The centrifugal casting system according to still another embodiment of the present invention may further include a vibration generator that vibrates the cooling water header at a constant period in the length direction or the width direction.

Advantages of the Invention

[0017] According to the present invention, since the upper end of the molten metal ladle in which the molten metal is stored can be opened and closed by the ladle cover and the auxiliary cover, in the process of transferring and injecting the molten metal ladle to the molten metal inlet of the casting mold, the phenomenon that the molten metal is cooled and solidified by the external air is prevented, thereby preventing the deterioration of the quality of the cast product.

[0018] In particular, when a hot air injection nozzle for injecting hot air is provided on the auxiliary cover, an air curtain by the hot air is formed in the process of discharging the molten metal, so that the cooling of the molten metal can be more effectively prevented, and high-quality cast products can be centrifugally cast.

[0019] In addition, there is also an advantage that the casting mold can be quickly and uniformly cooled immediately after the completion of centrifugal casting or during the centrifugal casting process, and the amount of cooling water used can be reduced.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4a

Figure 4b

Figure 5

Modes for Carrying Out the Invention

[0021] Before specifically describing the embodiments according to the present invention, it should be noted that the present invention is not limited to the configurations shown in the following detailed description or the accompanying drawings, and can be used or implemented in various ways.

[0022] Also, it should be noted that the expressions and terms used in this specification are for explanatory purposes only and should not be regarded as for limitation.

[0023] That is, as used in this specification, expressions such as "mounted", "installed", "connected", "coupled", "supported", "joined", etc. are used as broad expressions that include all direct and indirect mounting, installation, connection, coupling, support, and joining, unless otherwise indicated or limited to indicate something else. The expressions "connected", "coupled", "joined" are not limited to physical or mechanical connection, coupling, or joining.

[0024] Also, in this specification, terms indicating directions such as upper, lower, downward, upward, rear, bottom, front, rear part, etc. are used to explain the drawings, but such terms indicate directions relative to the drawings (when viewed normally) for convenience. Such terms indicating directions should not be accepted as limiting or restricting the present invention in any form literally.

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] FIGS. 1 to 5 are diagrams showing a centrifugal casting system according to an embodiment of the present invention.

[0027] Referring to FIGS. 1 and 2, the centrifugal casting system may include a main body 100, a casting mold 200 provided on the main body 100 for rotating molten metal at high speed for centrifugal casting, a mold driving unit for rotating the casting mold 200 at high speed, a molten metal supply unit 500 for supplying molten metal into the casting mold 200, and a cooling unit 400 for cooling the casting mold 200 or the casting product in the casting mold 200.

[0028] One end of the casting mold 200 is provided with a main flange 210 that is connected to and rotates with a mold driving part, and the other end is provided with a pressure flange 230. A main spindle 220 is coupled to the inner surface of the main flange 210, and a heating member 260 may be provided on the inner surface of the main flange 210. Also, a pressure spindle 240 is coupled to the inner surface of the pressure flange 230. The main spindle 220 and the pressure spindle 240 are coupled so as to be in surface contact with the inner surface of the end of the casting mold 200, and serve to prevent the molten metal flowing into the inside of the casting mold 200 from overflowing to the outside during casting. The main flange 210 formed on the outside of the main spindle 220 has an outer diameter larger than that of the main spindle 220 and, together with the pressure flange 230 formed on the opposite side, pressurizes and supports both end portions of the casting mold 200.

[0029] On the right side of the main body 100, a transfer table 110 that is movable in the main axis direction along a guide rail 120 formed on the bed is provided, and fixing means such as an eccentric cam or a bolt may be provided so that the transfer table 110 can be fixed at an appropriate position according to the length of the casting B (for example, a bearing for a refrigeration compressor) to be manufactured.

[0030] An injection pipe 275 having a molten metal injection port 270 that opens upward for injecting molten metal into the inside of the casting mold 200 is formed on the transfer table 110 so as to extend to the inside of the casting mold 200. Outside the injection pipe 275, a pressure flange 230 that is elastically supported by a bearing 232 and rotates, and a pressure spindle 240 are provided in front thereof so as to face the main spindle 220 and the main flange 210.

[0031] Since the pressure spindle 9 and the pressure flange 8 can move in the main axis direction together with the transfer table 110, there is an advantage that castings B of various lengths can be produced.

[0032] The mold driving unit includes a motor 310 and a driving pulley 320 that is connected through a shaft of the motor 310 and a belt 330 and rotates. The central portion of the driving pulley 320 is connected to the center of the main flange 210 via a driving shaft 340 to transmit a rotational force.

[0033] The cooling unit 400 sprays cooling water onto the casting mold 200 or the cast product, and cools the casting mold 200 or the cast product B as necessary after the centrifugal casting process or the completion of centrifugal casting. As shown in FIGS. 2 and 3, the cooling unit 400 is provided along the length direction of the casting mold 200 above the casting mold 200, and includes a cooling water header 410 that supplies cooling water, and a plurality of cooling water nozzles 420 that are arranged along the length direction of the cooling water header 410 and spray cooling water toward the casting mold 200.

[0034] The cooling water header 410 is connected via a hose to another cooling water supply device to be supplied with cooling water, and sprays it to the outside through the cooling water nozzles 420 to cool the casting mold 200 or the cast product B.

[0035] When cooling the casting mold 200 or the cast product B, if the cooling water is not sprayed uniformly over the entire casting mold 200 or the cast product B, the quality of the cast product B may deteriorate. Therefore, the cooling water nozzles 420 may be arranged so as not to be aligned in a straight line in the length direction, but to be displaced in the circumferential direction at a predetermined phase difference so as to spray the cooling water at different angles in the circumferential direction. That is, it is preferable to arrange the plurality of cooling water nozzles 420 in a staggered manner along the length direction of the cooling water header 410 so that uniform cooling water spraying is performed.

[0036] Further, the cooling water header 410 is provided slidably in the length direction or the width direction of the casting mold 200 via a guide rail member 431 at the upper part of the main body 100, and includes a vibration motor 432, a cam 433 that generates movement of the cooling water header 410 in the length direction or the width direction while rotating by the vibration motor 432, and a spring 434 that elastically supports the cooling water header 410 with respect to the main body 100. By using a vibration generator including these components, the cooling water header 410 can be vibrated in the length direction or the width direction at a constant period.

[0037] When cooling water is injected through the cooling water nozzle 420 while vibrating the cooling water header 410 in the length direction or the width direction at a constant period by using such a vibration generator, the cooling water can be uniformly injected over the entire casting mold 200 or the casting B. Therefore, the casting mold 200 or the casting B can be cooled quickly and uniformly, improving the quality and productivity.

[0038] On the other hand, the molten metal supply unit 500 is configured to supply molten metal to the inside of the casting mold 200 through the molten metal inlet 270, and is configured to prevent the molten metal from being cooled by contact with external air and solidifying during the transfer process and the injection process of the molten metal. If solidification of the molten metal occurs during the process of injecting the molten metal into the casting mold 200, the injection of the molten metal will not be smooth, and there may be problems such as a decrease in the quality and productivity of the casting B after centrifugal casting.

[0039] As shown in FIGS. 4a and 4b, the molten metal supply unit 500 may include a molten metal ladle 510 having a molten metal discharge port 511 through which molten metal is discharged on one side of the upper end, a ladle cover 520 that opens and closes the upper surface of the molten metal ladle 510, an auxiliary cover 530 that is movably provided on one side of the ladle cover 520 and opens the molten metal discharge port 511 when the molten metal ladle 510 is inclined to one side so as to discharge molten metal through the molten metal discharge port 511, and a ladle transfer unit that transfers the molten metal ladle 510.

[0040] The molten metal ladle 510 is cylindrical with an open upper surface and stores the molten metal to be poured into the casting mold 200. The molten metal discharge port 511 of the molten metal ladle 510 is triangular and protrudes outward on one side of the upper end of the molten metal ladle 510, and the molten metal is poured while collecting it toward the molten metal inlet 270.

[0041] The ladle cover 520 is formed in a disk shape having a diameter and shape corresponding to the upper end of the molten metal ladle 510, and one end may be rotatably provided on the upper end of the molten metal ladle 510 via a cover hinge shaft 521.

[0042] The auxiliary cover 530 is provided to rotate about a hinge shaft 531 on one side of the ladle cover 520, and when the ladle cover 520 covers the upper end of the molten metal ladle 510, the auxiliary cover 530 closes the upper part of the molten metal discharge port 511. In this way, since the upper end of the molten metal ladle 510 is completely closed by the ladle cover 520 and the auxiliary cover 530, it is possible to prevent the molten metal in the molten metal ladle 510 from cooling due to contact with the external air.

[0043] In order for the auxiliary cover 530 to automatically open the molten metal discharge port 511 when the molten metal ladle 510 inclines toward the molten metal discharge port 511, the upper surface of the auxiliary cover 530 is connected to the structure 550 of the ladle transfer unit by a link bar 560. When the molten metal ladle 510 inclines to one side, the auxiliary cover 530 can rotate about the hinge shaft 531 by the link bar 560 to open the molten metal discharge port 511. Here, the structure 550 of the ladle transfer unit may be an inverted "U" - shaped ladle mounting member whose both ends are connected to the side surface of the molten metal ladle 510 via ladle rotation shafts 551 so as to be relatively rotatable and is coupled to a crane or a mobile trolley.

[0044] When the molten metal ladle 510 inclines toward the molten metal discharge port 511 and the auxiliary cover 530 is opened, the molten metal may flow out through the molten metal discharge port 511 and come into contact with the external air and rapidly cool.

[0045] To prevent this, as shown in FIG. 5, at the end of the auxiliary cover 530, a hot air injection nozzle 570 that injects hot air toward the molten metal discharge port 511 when the auxiliary cover 530 is opened, and a hot air supplier 575 that heats air and supplies it to the hot air injection nozzle 570 may be further provided.

[0046] A plurality of the hot air injection nozzles 570 are arranged along the peripheral portion of the auxiliary cover 530, form an air curtain that injects hot air toward the molten metal discharge port 511 to prevent external air from contacting the molten metal, and also act to heat the molten metal injected toward the molten metal inlet 270 to maintain the temperature.

[0047] The hot air supplier 575 may include a fan 577 that sucks in and sends external air, a heater 576 that heats the air sucked in by the fan 577, and a flexible heat-resistant material hose 578 that guides the heated air to the hot air injection nozzle 570.

[0048] Also, in order to minimize the temperature drop of the molten metal during the process of transferring the molten metal in the molten metal ladle 510, a heat reflection member 540 in which a heat reflection film is laminated on the outer surface of a heat insulating material may be attached to the lower surface of the ladle cover 520.

[0049] The centrifugal casting system according to the present invention as described above operates as follows.

[0050] First, the transfer table 110 is expanded to the right side in the drawing, and the pressurizing spindle 240 and the main spindle 220 are respectively inserted and coupled inside both sides of the casting mold 200, and the main flange 210 and the pressurizing flange 230 pressurize and support both ends of the casting mold 200.

[0051] In this state, the molten metal ladle 510 containing the molten metal is moved toward the casting mold 200 using a crane or a ladle transfer unit with a mobile trolley structure. At this time, the upper end of the molten metal ladle 510 is shielded by the ladle cover 520 and the auxiliary cover 530, so that the molten metal in the molten metal ladle 510 does not come into contact with the external air, and the cooling of the molten metal can be prevented.

[0052] Next, the molten metal ladle 510 is tilted with the tip of the molten metal discharge port 511 of the molten metal ladle 510 aligned with the molten metal inlet 270 on one side of the casting mold 200.

[0053] As the molten metal ladle 510 tilts toward the molten metal discharge port 511, the auxiliary cover 530 rotates about the hinge shaft 531 by the link bar 560 to open the molten metal discharge port 511, and the molten metal inside the molten metal ladle 510 flows out through the molten metal discharge port 511 and into the molten metal inlet 270.

[0054] When a certain amount of molten metal is injected into the casting mold 200 through the molten metal inlet 270, the injection of molten metal through the molten metal ladle 510 is interrupted, and the casting mold 200 is rotated at high speed while receiving the rotational force from the motor 310 to perform centrifugal casting.

[0055] During the centrifugal casting process or when the centrifugal casting is completed as needed, cooling water is supplied to the cooling water header 410, and the cooling water is sprayed onto the casting mold 200 or the casting B inside the casting mold 200 through the cooling water nozzles 420. Since the cooling water nozzles 420 are arranged in a staggered pattern along the length direction, uniform cooling water spraying can be performed toward the casting mold 200.

[0056] At this time, by reciprocating the cooling water header 410 in the length direction or the width direction at a certain distance with a vibration generator, more uniform cooling water spraying can be performed, and the cooling performance can be further improved.

[0057] As described above, the present invention has been described in detail with reference to the embodiments. However, it is natural that those with ordinary knowledge in the technical field to which the present invention pertains can make various substitutions, additions, and modifications without departing from the technical idea described above. It should be understood that such modified embodiments also fall within the protection scope of the present invention defined by the appended claims.

Explanation of Reference Numerals

[0058] 100: Main body 110: Transfer table 200: Casting mold 270: Molten metal inlet 310: Motor 400: Cooling unit 410: Cooling water header 420: Cooling water nozzle 431: Guide rail member 432: Vibration motor 433: Cam 434: Spring 500: Molten metal supply unit 510: Molten metal ladle 511: Molten metal discharge port 520: Ladle cover 530: Auxiliary cover 540: Heat reflection member 550: Structure of ladle transfer unit 560: Link bar 570: Hot air injection nozzle 575: Hot air supplier

Claims

1. a casting mold having a molten metal inlet through which molten metal is injected; a mold driving unit that rotates the casting mold; a molten metal supply unit including: a molten metal ladle for storing molten metal to be poured into the casting mold and having a molten metal outlet port at one side of an upper end thereof through which the molten metal is discharged; a ladle cover for opening and closing an upper surface of the molten metal ladle; an auxiliary cover movably provided at one side of the ladle cover for opening the molten metal outlet port when the molten metal ladle is tilted to one side to discharge the molten metal through the molten metal outlet port; and a ladle transport unit for transporting the molten metal ladle; Centrifugal casting system.

2. 2. The centrifugal casting system according to claim 1, wherein the auxiliary cover is provided on one side of the ladle cover so as to rotate around a hinge axis, and an upper surface of the auxiliary cover is connected to a structure of the ladle transfer unit by a link bar, and when the molten metal ladle is tilted to one side, the auxiliary cover rotates around the hinge axis by the link bar to open the molten metal discharge port.

3. 3. The centrifugal casting system according to claim 2, further comprising: a hot air injection nozzle at an end portion of the auxiliary cover, which injects hot air toward the molten metal discharge port when the auxiliary cover is opened; and a hot air supplier which heats air and supplies it to the hot air injection nozzle.

4. 4. The centrifugal casting system according to claim 1, wherein a heat reflecting member having a heat reflecting film laminated on an outer surface of a thermal insulating material is attached to a lower surface of the ladle cover.

5. a cooling water header provided on an upper side of the casting mold along a length direction of the casting mold for supplying cooling water; and a plurality of cooling water nozzles arranged on the cooling water header along a length direction of the casting mold for spraying cooling water toward the casting mold, 2. The centrifugal casting system according to claim 1, wherein the plurality of cooling water nozzles are arranged so as to be shifted from each other in the circumferential direction by a predetermined phase difference so as to spray the cooling water at different angles in the circumferential direction.

6. The centrifugal casting system according to claim 5 , further comprising a vibration generator for vibrating the cooling water header in a lengthwise or widthwise direction at a constant period.

Images