A method of die-casting by uniformly charging molten metal to manufacture electric rotor

Abstract

The present invention aims to solve the above-mentioned problems by providing a die-casting method for uniformly filling molten metal of an electric motor rotor, which maximizes the overlapping area between the slot groove (120) of the slot core (100) and the in-gate (330) of the lower mold (300) to improve the molten metal filling rate of the slot groove (120) and maintain uniform quality. To achieve the above objective, the die-casting method for molten metal filling homogenization of an electric motor rotor according to the present invention comprises: a core stacking step (S10) of stacking a plurality of slot cores (100) vertically; a core placement step (S20) of placing the stacked slot cores (100) on the upper part of a lower mold (300); a molten metal injection step (S30) of injecting molten metal into an injection machine (20); a mold transfer step (S40) of transferring the lower mold (300) to the injection machine (20); an injection step (S50) of lowering the upper mold to the lower mold (300) and then operating the injection machine (20) to inject molten metal into the lower mold (300); and an extraction step (S60) of separating the rotor product after injection is completed from the lower mold (300).

Description

Technology Field

[0001] The present invention relates to a die-casting method for homogenizing molten metal filling of an electric motor rotor, and more particularly to a die-casting method for homogenizing molten metal filling of an electric motor rotor for improving the filling rate by ensuring that the molten metal is uniformly injected into the core during molten metal injection. Background Technology

[0003] Generally, an induction motor consists of a stator that forms a rotating magnetic field by flowing alternating current through windings and a rotor that rotates by that magnetic field.

[0004] Rotors can be classified according to the production method into a copper bar type, which is manufactured by inserting copper bars into the slots of the rotor core and joining both ends with end rings, and a die-casting type, which fills the slots of the rotor core using an aluminum die-casting method.

[0005] In particular, due to the high productivity of the die-casting method, small general-purpose induction motors are manufactured using this method; conversely, for medium and large-sized motors, the copper bar type, which has lower productivity due to the difficulties of die-casting, is currently being applied more frequently. However, with the recent advancements in die-casting technology, the production of die-cast rotors is gradually increasing even for medium and large-sized models.

[0006] In this die casting process, with the rotor core inserted into the die casting mold, molten aluminum is pushed into the slots of the rotor core to form conductor bars, end rings, and braids.

[0007] At this time, the molten material is injected along the runner formed in the die-casting mold into the area where the rotor core is inserted, and the air inside the die-casting mold is expelled to the outside through the air vent.

[0008] However, in the conventional die-casting process, the molten material is not supplied uniformly into the die-casting mold, resulting in a problem where molten material is not supplied to some iron cores. This leads to issues such as appearance defects or the formation of internal pores, which lowers production yield. Prior art literature

[0010] Republic of Korea Registered Patent No. 10-1541274 The problem to be solved

[0011] The present invention aims to solve the above-mentioned problems by providing a die-casting method for uniformly filling molten metal of an electric motor rotor, which maximizes the overlapping area between the slot groove (120) of the slot core (100) and the in-gate (330) of the lower mold (300) to improve the molten metal filling rate of the slot groove (120) and maintain uniform quality. means of solving the problem

[0013] To achieve the above objective, the die-casting method for molten metal filling homogenization of an electric motor rotor according to the present invention comprises: a core stacking step (S10) of stacking a plurality of slot cores (100) vertically; a core placement step (S20) of placing the stacked slot cores (100) on the upper part of a lower mold (300); a molten metal injection step (S30) of injecting molten metal into an injection machine (20); a mold transfer step (S40) of transferring the lower mold (300) to the injection machine (20); an injection step (S50) of lowering the upper mold to the lower mold (300) and then operating the injection machine (20) to inject molten metal into the lower mold (300); and an extraction step (S60) of separating the rotor product after injection is completed from the lower mold (300).

[0014] In the above core stacking step (S10), the slot core (100) is inserted into the dummy pin (200) and stacked vertically.

[0015] The above dummy pin (200) has a guide pin (210) formed protruding from its side, and the guide pin (210) guides a plurality of the slot cores (100) to be aligned with a certain basic position.

[0016] In the above core mounting step (S20), when mounting the slot core (100) onto the lower mold (300), the slot core (100) is positioned so as to be offset by 1 to 1.5 degrees from the basic position.

[0017] A first dummy hole (110) through which the dummy pin (200) passes is formed in the slot core (100), and a plurality of slot grooves (120) are formed on the outer side of the first dummy hole (110).

[0018] The above slot grooves (120) consist of 40 slots and are arranged in a circular pattern at regular angle intervals centered on the dummy hole (110).

[0019] A second dummy groove (320) into which the dummy pin (200) is inserted is formed in the lower mold (300).

[0020] An in-gate (330) into which molten metal is injected is formed in the lower mold (300) above.

[0021] The above ingate (330) consists of 12 and is arranged in a circular pattern at regular angle intervals centered on the second dummy groove (320). Effects of the invention

[0023] The die-casting method for homogenizing molten metal filling of an electric motor rotor according to the present invention, as described above, has the following effects.

[0024] In the core mounting step (S20), the slot core (100) is fixed by rotating it 1 to 1.5 degrees from its basic position, thereby increasing the overlapping area between the slot groove (120) and the in-gate (330), and thereby providing the effect of increasing the molten metal filling rate of the slot groove (120) in the injection step (S50).

[0025] In addition, the molten metal filling rate of the slot groove (120) is increased, providing the effect of improving the durability and quality of the product. Brief explanation of the drawing

[0027] FIG. 1 is a flowchart of a die-casting method for homogenizing molten metal filling of an electric motor rotor according to an embodiment of the present invention. FIG. 2 is a drawing showing a dummy pin (200) and a slot core (100) during the core stacking step (S10) of a die-casting method for molten metal filling homogenization of an electric motor rotor according to an embodiment of the present invention. FIG. 3 is a drawing showing the lower mold (300) and the slot core (100) during the core seating step (S20) of the molten metal filling homogenization die-casting method for an electric motor rotor according to an embodiment of the present invention. FIG. 4 is a diagram showing the molten metal injection step (S30) of the molten metal filling homogenization die-casting method for an electric motor rotor according to an embodiment of the present invention. FIG. 5 is a drawing showing the injection step (S50) of the molten metal filling homogenization die-casting method for an electric motor rotor according to an embodiment of the present invention. FIG. 6 is a graph showing the range of overlapping areas according to the basic position and angle change of the slot core (100) according to the molten metal filling homogenization die-casting method of an electric motor rotor according to an embodiment of the present invention. FIG. 7 is a graph comparing the basic position of the slot core (100) and the filling state of the slot groove (120) according to the angle change according to the die-casting method for molten metal filling homogenization of the motor rotor according to an embodiment of the present invention. Specific details for implementing the invention

[0028] The following detailed description of the invention refers to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that various embodiments of the invention are different but need not be mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in relation to one embodiment. It should also be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. Accordingly, the following detailed description is not intended to be limiting, and the scope of the invention is limited only by the appended claims, including all equivalents to those claimed therein, provided appropriately described. Similar reference numerals in the drawings refer to the same or similar functions across various aspects.

[0029] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

[0030] As illustrated in FIGS. 1 to 7, the die-casting method for homogenizing molten metal filling of an electric motor rotor according to an embodiment of the present invention comprises a core stacking step (S10), a core seating step (S20), a molten metal injection step (S30), a mold transfer step (S40), an injection step (S50), and an extraction step (S60).

[0031] In the above core stacking step (S10), as shown in FIG. 1, a plurality of slot cores (100) are stacked vertically around a dummy pin (200) to assemble them.

[0032] Specifically, the slot core (100) is formed in the shape of a flat disc, a first dummy hole (110) is formed in the center, and a slot groove (120) is formed on the outer side.

[0033] The first dummy hole (110) is formed in a circular shape and penetrates vertically, and a first guide groove (111) is formed on one side to guide the angle.

[0034] The above slot grooves (120) are parts into which molten metal is injected during injection, and 40 of them are formed in one slot core (100), and are formed spaced apart at a certain angle from the center of the first dummy hole (110).

[0035] The above dummy pin (200) is formed in a cylindrical shape, and a guide pin (210) is provided protruding from one side of the outer side to guide the basic position when assembling the slot core (100) and the lower mold (300).

[0036] In addition, a connecting link (220) is formed on the upper part of the dummy pin (200) to be connected to a transfer device during transfer, and a locking part is formed protruding from the lower part to prevent the slot core (100) from falling out downward.

[0037] In the above core stacking step (S10), after setting up the dummy pin (200), a plurality of slot cores (100) are stacked from the bottom of the dummy pin (200).

[0038] At this time, the guide pin (210) is inserted into the first guide groove (111) so that the slot core (100) is positioned at the same angle, and as a result, the slot grooves (120) are positioned so that they align vertically and are stacked in an interconnected manner.

[0040] In the above core placement step (S20), the slot core (100) stacked on the dummy pin (200) is moved to the lower mold (300) together with the dummy pin (200) and placed on the lower mold (300).

[0041] The lower mold (300) is formed in a roughly rectangular shape, and a cavity portion (310) is formed in which the slot core (100) is seated.

[0042] The above cavity portion (310) is formed in a circular shape to form the end ring portion of the rotor, and a second dummy groove (320) into which the dummy pin (200) is inserted is formed in the center of the above cavity portion (310), and an in-gate (330) into which molten metal is injected is formed on the outer side of the second dummy groove (320).

[0043] The above in-gate (330) consists of 12 and is spaced apart at a certain angle from the center of the second dummy home (320).

[0044] In the second dummy groove (320), a second guide groove (321) is formed into which the guide pin (210) of the dummy pin (200) is inserted.

[0045] When the slot core (100) is seated on the lower mold (300), the guide pin (210) of the dummy pin (200) is inserted into the second guide groove (321), so that the slot core (100) is seated in the basic position. It can be.

[0046] Then, after the slot core (100) is placed in the basic position of the lower mold (300), the slot core (100) is rotated at an angle of 1 to 1.5 degrees and fixed.

[0047] When the above slot core (100) is fixed to the above basic position and injected, there was a problem in that the filling rate of the above slot groove (120) was low, resulting in a decrease in product quality.

[0048] To solve this, in an embodiment of the present invention, a simulation was performed to find a location to increase the filling rate of the slit groove (120) in the injection step (S50).

[0049] FIG. 6 shows the simulation of the overlapping area between the slot groove (120) and the in-gate (330) when the slot core (100) is in the basic position and when it is changed from the basic position to 0.5 degrees, 1 degree, 1.5 degrees, 2 degrees, and 2.25 degrees.

[0050] As a result, as shown in Fig. 6, the calculated values ​​were 728.68 mm² at the basic position, 729.2 mm² at a change angle of 0.5 degrees, 759.4 mm² at a change angle of 1 degree, 789 mm² at a change angle of 1.5 degrees, 772.32 mm² at a change angle of 2 degrees, and 746.8 mm² at a change angle of 2.25 degrees.

[0051] FIG. 7 simulates the filling rate of the slot groove (120) when the slot core (100) is in the basic position and when it is changed from the basic position to 0.5 degrees, 1 degree, 1.5 degrees, 2 degrees, and 2.25 degrees, and shows this as a bar graph.

[0052] Looking at the graph shown in FIG. 7, the filling efficiency increases as the number of slots indicated by bars increases; therefore, the filling rate of the slot groove (120) is best when the angle is 1 to 1.5 degrees.

[0053] As such, it was found that when the slot core (100) was rotated 1 to 2 degrees from the basic position, the overlapping area between the slot groove (120) and the in-gate (330) was high, and when the slot core (100) was rotated 1 to 1.5 degrees from the basic position, the filling rate of the slot groove (120) was found to be the best.

[0054] Accordingly, in the core mounting step (S20), the slot core (100) is fixed by rotating it 1 to 1.5 degrees from the basic position, thereby increasing the molten metal filling rate of the slot groove (120) and providing the effect of improving quality.

[0056] In the above molten metal injection step (S30), the operation of scooping molten metal with a ladle device (10) and transferring it to an injection machine (20) is performed.

[0057] The molten metal is filled into the injection molding machine (20), and in the mold transfer step (S40), the lower mold (300) is moved onto the injection molding machine (20) together with the slot core.

[0058] Afterwards, in the injection step (S50), the upper mold placed on the injection machine (20) is lowered and fixed to the lower mold (300), and a rotor product is injected as molten metal is injected between the lower mold (300) and the upper mold through the injection machine (20).

[0059] In the above extraction step (S60), the rotor product that has been injected is separated from the lower mold (300).

[0061] The die-casting method for homogenizing molten metal filling of an electric motor rotor according to an embodiment of the present invention, which is configured as above, increases the overlapping area between the slot groove (120) and the in-gate (330) by rotating and fixing the slot core (100) from its basic position by 1 to 1.5 degrees in the core seating step (S20), thereby providing the effect of increasing the molten metal filling rate of the slot groove (120) in the injection step (S50).

[0062] In addition, the molten metal filling rate of the slot groove (120) is increased, providing the effect of improving the durability and quality of the product.

[0064] The present invention is not limited thereto and may be modified in various forms by those skilled in the art without departing from the spirit and scope of the following appended claims; therefore, such modifications should be interpreted as being within the scope of the present invention. Explanation of the symbols

[0066] S10: Core stacking stage S20: Core seating stage S30: Molten metal injection stage S40: Mold transfer stage S50: Injection stage S60: Ejection stage 100: Slot core 110: First dummy hole 111: Second guide groove 120: Slit groove 200: Dummy pin 210: Guide pin 220: Connecting link 300: Lower mold 310: Cavity section 320: Second dummy groove 321: Second guide groove 330: In-gate 400: Upper mold

Claims

Claim 1 A core stacking step (S10) for stacking multiple slot cores (100) vertically; a core placement step (S20) for placing the stacked slot cores (100) on the upper part of a lower mold (300); a molten metal injection step (S30) for injecting molten metal into an injection machine (20); a mold transfer step (S40) for transferring the lower mold (300) to the injection machine (20); an injection step (S50) for lowering the upper mold to the lower mold (300) and then operating the injection machine (20) to inject molten metal into the lower mold (300); and an extraction step (S60) for separating the rotor product after injection is completed from the lower mold (300). In a die-casting method for molten metal filling homogenization of an electric motor rotor characterized by including, in the core stacking step (S10), the slot core (100) is inserted into a dummy pin (200) and stacked vertically, the slot core (100) is formed in the shape of a flat disc, a first dummy hole (110) is formed in the center, and a plurality of slot grooves (120) are formed on the outer side, the first dummy hole (110) is formed vertically through in a circular shape, and a first guide groove (111) for guiding an angle is formed on one side, the dummy pin (200) is formed in a cylindrical shape, and a guide pin (210) is provided protruding from one side of the outer side to guide the basic position when assembling the slot core (100) and the lower mold (300), and in the core stacking step (S10).After setting up the dummy pin (200), a plurality of slot cores (100) are stacked from the bottom of the dummy pin (200), and the guide pin (210) is inserted into the first guide groove (111) so that the slot cores (100) are arranged at the same angle, and as a result, the slot grooves (120) are arranged vertically in alignment and stacked in an interconnected manner. Then, in the core seating step (S20), the slot cores (100) stacked on the dummy pin (200) are moved together with the dummy pin (200) to the lower mold (300) and seated on the lower mold (300). The lower mold (300) is formed in a roughly rectangular shape, and a cavity portion (310) for the slot cores (100) to be seated is formed, and the cavity portion (310) is formed in a circular shape to form the end ring portion of the rotor. A second dummy groove (320) into which the dummy pin (200) is inserted is formed in the center of the cavity portion (310), and a plurality of in-gates (330) into which molten metal is injected are formed on the outer side of the second dummy groove (320) and are arranged spaced apart at a certain angle from the center of the second dummy groove (320). A second guide groove (321) into which the guide pin (210) of the dummy pin (200) is inserted is formed in the second dummy groove (320), so that when the slot core (100) is seated on the lower mold (300), the guide pin (210) of the dummy pin (200) is seated in the basic position into which it is inserted into the second guide groove (321). Furthermore, in order to increase the filling rate of the slot groove (120) in the injection step (S50), the core seating step (S20) A die-casting method for homogenizing molten metal filling of an electric motor rotor, characterized by additionally including the step of fixing the slot core (100) by rotating it at an angle of 1 to 1.5 degrees after the slot core (100) is seated at the basic position of the lower mold (300). Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A die-casting method for homogenizing molten metal filling of an electric motor rotor according to claim 1, characterized in that the slot grooves (120) are composed of 40 and are arranged in a circular pattern at regular angle intervals centered on the first dummy hole (110). Claim 7 delete Claim 8 delete Claim 9 A die-casting method for homogenizing molten metal filling of an electric motor rotor, characterized in that, in claim 1 or 6, the ingate (330) is composed of 12 and arranged in a circular pattern at regular angle intervals centered on the second dummy groove (320). Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete

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