KR20030063864A - induction motor and method for manufacturing the rotor and stator of the same - Google Patents

Abstract

PURPOSE: An inductive motor and a method for fabricating a rotor and a stator thereof are provided to prevent the leakage of the current induced from a stator conductor by forming an insulating film of zinc phosphate on a rotor slot of a rotor core. CONSTITUTION: An inductive motor includes a stator core(11), a coil(15), a rotor core(21), and a rotor conductor(25). The stator core includes a plurality of stator slots and a steel plate(11a). The stator slots(13) are formed on the steel plates to a radiative direction according to a predetermined interval. The stator core is formed by stacking the steel plates. The coil is wound around the stator slots in order to form the rotary magnetic field. The rotor core is formed by stacking continuously the plural electric steel plates on which a plurality of rotor slots(23) are formed in a predetermined interval. An insulating film(100) is formed on the rotor core in order to prevent the leakage of current. The rotor conductor is formed at the rotor slots in order to generate the torque by the current induced from the coil.

Description

Induction motor and method for manufacturing the rotor and stator of the same}

The present invention relates to an induction motor, and more particularly, to an induction motor and an induction motor capable of reducing iron loss caused by drift load loss or eddy current caused by deterioration of insulation of a steel plate during the process of making a rotor or stator. It relates to a method of manufacturing the electron and the stator.

In general, an electric motor is a machine that obtains rotational power by converting electrical energy into mechanical energy, and is roughly classified into an AC motor and a DC motor, and among them, an induction motor is a kind of AC motor.

Such an induction motor is a kind of typical AC motor that obtains a rotational torque by the interaction between the current induced in the secondary winding and the rotor magnetic field by the electromagnetic induction of the primary winding connected to the power source.

Hereinafter, the structure of the above-mentioned induction motor with reference to the accompanying drawings schematically described as follows.

First, Figure 1 is a cross-sectional view schematically showing the structure of a general induction motor, the induction motor is a rotor that forms a concentric circle with the stator 10, the stator to maintain a predetermined void (a) on the inner periphery of the stator And a shaft 30 press-fitted to the center of the rotor to transmit the rotational force of the rotor to the driven shaft.

The stator 10 includes a coil 15 that receives an alternating current power to form a rotating magnetic field, and a stator iron core 11 of a magnetic material that forms a passage for magnetic flux generated by the rotating magnetic field. At this time, the stator iron core 11 is configured by stacking a plurality of circular silicon steel plate (11a) in which a plurality of stator slots 13 are formed radially on the inner circumference so that the stator slots are continuous along the axial direction, Through the stator slot 13 the coil 15 is wound in various ways.

The rotor 20 is a rotor conductor 25 for generating torque by the interaction of the current induced by the coil 15 with the magnetic flux, and a rotor iron core 21 of the magnetic body forming a passage of the magnetic flux. Is done. At this time, the rotor core 21 is a circular silicon steel plate 21a in which a plurality of rotor slots 23 are radially formed at a predetermined interval on the outer circumferential side of the rotor slot along the axial direction. A plurality of stacks are formed so as to be continuous, and a metal such as aluminum or copper having high conductivity is inserted into the rotor slot 23 to form the rotor conductor 25. In addition, end rings 27 are formed at both ends of the rotor conductor 25 to form a circuit by connecting the rotor conductors to each other. At this time, the rotor conductor 25 and the end ring 27 is generally applied to a large number of aluminum die casting method.

Referring to the operation of the induction motor configured as described above, the alternating current is applied to the coil 15 generates a magnetic field to rotate the magnetic flux through the stator core (11), the rotating magnetic flux is a void (a By linking with the rotor conductor 25 through), a current is induced in the rotor conductor. At this time, the current induced in the rotor conductor 25 generates a torque in accordance with Fleming's left hand law together with the magnetic flux.

By the way, as described above, the induction motor has a low efficiency when there is a leakage of current or magnetic flux, and the steel plate constituting the stator iron core 11 or the rotor iron core 21 for this purpose. Significant effort has been invested in ensuring the insulation of In general, the steel sheets 11a and 21a applied to the stator iron core 11 and the rotor iron core 21 are formed with an insulating coating (not shown) coated with phosphate or the like in advance to ensure insulation. However, in order to use the steel sheets 11a and 21a as stator iron cores or rotor iron cores, a punching process for forming stator slots 13 or rotor slots 23 in the steel sheet is required. Most of the insulating film on the board was destroyed. The problem caused by this will be briefly described with reference to the accompanying drawings.

First, FIG. 2A is a cross-sectional view showing current leakage occurring between the rotor conductor and the steel plate in the induction motor according to FIG. 1, and FIG. 2B shows the eddy current path flowing through the rotor steel plate in the induction motor according to FIG. One cross section.

As shown in FIG. 2A, when the insulating film is broken on the steel plate 21a constituting the rotor iron core, a phenomenon in which a current flowing through the rotor conductor 25 leaks to the steel sheet occurs. The current induced in the rotor conductor 25 should flow along the rotor conductor, but as described above, when leakage into the steel plate 21a, the torque is weakened and heat is generated from the rotor core. It has been adversely affected. This loss is called a drift load loss and was a major cause of deterioration of the efficiency of the induction motor.

Next, as shown in FIG. 2B, an eddy current is generated in the steel plate 21a constituting the rotor iron core as the magnetic flux changes seamlessly, and the eddy current is a path as shown by a dotted line. ) Will flow along. However, as insulation is not secured between the steel sheets 21a, eddy currents form a path crossing between adjacent steel sheets. At this time, since the steel sheet 21a acts as a resistance in terms of current, the longer the eddy current path, the greater the resistance, which eventually leads to iron loss, which together with the aforementioned drifting load loss greatly reduces the efficiency of the induction motor. It became.

Iron loss due to the eddy current path was the same problem caused when the insulating film is not formed between the steel sheets in the stator iron core as well as the rotor iron core.

The present invention has been made to solve the above problems, an object of the present invention is to provide an induction motor and the induction motor that can improve the efficiency by preventing the drift load loss caused by leakage of current between the rotor conductor and the steel sheet It is to provide a rotor manufacturing method.

Another object of the present invention is to reduce the iron loss by reducing the eddy current path formed between the steel core constituting the rotor iron core or stator iron core and to improve the efficiency of the induction motor and the manufacturing method of the rotor and stator of the induction motor To provide.

1 is a cross-sectional view schematically showing the structure of a general induction motor

Figure 2a is a cross-sectional view showing the current leakage occurring between the rotor conductor and the steel plate in the induction motor according to Figure 1

Figure 2b is a cross-sectional view showing the eddy current path flowing through the rotor steel plate in the induction motor according to Figure 1

3 is a cross-sectional view schematically showing the structure of an induction motor according to a first embodiment of the present invention;

4 is a cross-sectional view showing a part of the rotor steel plate of the induction motor according to FIG.

Figures 5a and 5b is a flow chart showing in detail the entire flow chart and the insulating film forming step showing the rotor manufacturing method of the induction motor according to Figure 3

6 is a cross-sectional view schematically showing the structure of an induction motor according to a second embodiment of the present invention.

7 is a cross-sectional view showing an eddy current path flowing through a rotor steel plate in the induction motor according to FIG. 6.

8 is a flow chart showing a rotor manufacturing method of the induction motor according to FIG.

9 is a sectional view schematically showing the structure of an induction motor according to a third embodiment of the present invention.

10 is a cross-sectional view showing an eddy current path flowing through the stator steel plate in the induction motor according to FIG.

11 is a flowchart illustrating a stator manufacturing method of an induction motor according to FIG. 9.

Explanation of symbols on the main parts of the drawings

10 stator 11: stator core

11a: stator iron core steel plate 20: rotor

21: rotor iron core 21a: rotor iron core steel plate

23: rotor slot 30: shaft

100,200,300: Insulation coating

In order to achieve the above object, an induction motor of one embodiment of the present invention is a stator configured by stacking a plurality of steel plates in which a plurality of stator slots are formed radially at predetermined intervals so that the stator slots are continuous in the axial direction. Iron core; A coil wound around the stator slot to form a rotating magnetic field when AC power is applied; Concentric circles with the stator iron core and a plurality of rotor slots are formed by stacking a plurality of radially formed radially at a predetermined interval so that the rotor slot is continuous along the axial direction, the current leakage in the rotor slot A rotor iron core having an insulating coating formed thereon to block the material from being formed; And a rotor conductor provided in the rotor slot and configured to generate torque by a current induced from the coil.

At this time, the method for manufacturing the rotor of the induction motor of one embodiment of the present invention includes a punching step of forming a rotor slot at a predetermined position of a thin steel plate using a press die; Lamination step of manufacturing the rotor iron core by aligning the punched steel sheet so that the rotor slots are continuous along the axial direction; An insulating film forming step of forming an insulating film in the rotor slot by impregnating the rotor iron core with the insulating film coating agent for a predetermined time; And inserting the rotor iron core into a mold, injecting aluminum melt, and then applying pressure to form a rotor conductor and an end ring.

Therefore, according to one embodiment of the present invention, by forming an insulating film in the rotor slot, it is possible to prevent the current induced by the rotor conductors from leaking to the steel sheet, thereby reducing the drift load loss.

Next, an induction motor according to another aspect of the present invention includes a stator iron core configured by stacking a plurality of steel plates in which a plurality of stator slots are formed radially at predetermined intervals so that the stator slots are continuous in the axial direction; A coil wound around the stator slot to form a magnetic field when AC power is applied; Concentric circles with the stator iron core, a plurality of rotor slots are formed by laminating a plurality of steel sheets formed radially at a predetermined interval so that the rotor slots are continuous along the axial direction, interlayer insulation between the steel sheets A rotor iron core in which an insulating coating film is secured; And a rotor conductor provided in the rotor slot to form a rotor field in which torque is generated by current induced from the coil.

At this time, the method for manufacturing a rotor of the induction motor according to another aspect of the present invention comprises a punching step of forming a rotor slot in a predetermined position of a thin steel plate using a press die; An insulating film forming step of forming an insulating film on both sides of the steel sheet by impregnating the punched steel sheet with an insulating coating coating agent for a predetermined time; Laminating the impregnated steel sheet so that the rotor slots are continuous along the axial direction to produce a rotor iron core; And inserting the rotor iron core into a mold, injecting aluminum melt, and then applying pressure to form a rotor conductor and an end ring.

Therefore, according to another embodiment of the present invention, as the insulating film is formed on the steel sheet constituting the rotor iron core, it is possible to prevent the eddy current path flowing to the adjacent steel sheet, thereby reducing the iron loss.

Next, the induction motor according to another embodiment of the present invention is configured by stacking a plurality of steel plates in which a plurality of stator slots are formed radially at a predetermined interval so that the stator slots are continuous along the axial direction, and between the steel plates A stator iron core on which an insulating film for securing interlayer insulation is formed; A coil wound around the stator slot to form a magnetic field when AC power is applied; A rotor iron core concentric with the stator iron core and configured by stacking a plurality of steel plates in which a plurality of rotor slots are radially formed at predetermined intervals so that the rotor slots are continuous in the axial direction; And a rotor conductor provided in the rotor slot and configured to generate torque by a current drawn from the coil.

At this time, the method for manufacturing a stator of an induction motor according to another aspect of the present invention comprises a punching step of forming a stator slot in a predetermined position of a thin steel plate using a press die; An insulating film forming step of forming an insulating film on both sides of the steel sheet by impregnating the punched steel sheet with an insulating coating coating agent for a predetermined time; And laminating the impregnated steel sheet so that the stator slots are continuous along the axial direction to produce a stator iron core.

Therefore, according to another embodiment of the present invention, as the insulating film is formed on the steel plate constituting the stator iron core, it is possible to prevent the eddy current path flowing to the adjacent steel plate, thereby reducing the iron loss.

Hereinafter, an induction motor and its rotor and stator manufacturing method according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, Figure 3 is a cross-sectional view schematically showing the structure of the induction motor according to the first embodiment of the present invention, Figure 4 is a cross-sectional view showing a part of the rotor steel plate of the induction motor according to Figure 3, Figures 5a and 5b 3 is a flow chart showing in detail the entire flow chart and the insulating film forming step showing the rotor manufacturing method of the induction motor according to FIG.

As shown in FIG. 3, the induction motor according to the first embodiment of the present invention has a stator 10 and a rotor 20 which forms a concentric circle with the stator and maintains a predetermined gap a in the inner circumference of the stator. And a shaft 30 press-fitted to the center of the rotor to transmit the rotational force of the rotor to the driven shaft.

The stator 10 includes a coil 15 that receives an alternating current power to form a rotating magnetic field, and a stator iron core 11 of a magnetic material that forms a passage for magnetic flux generated by the rotating magnetic field. At this time, the stator iron core 11 is configured by stacking a plurality of circular silicon steel plate (11a) in which a plurality of stator slots 13 are formed radially on the inner circumference so that the stator slots are continuous along the axial direction, Through the stator slot 13 the coil 15 is wound in various ways.

The rotor 20 is a rotor conductor 25 for generating torque by the interaction of the current induced by the coil 15 with the magnetic flux, and a rotor iron core 21 of the magnetic body forming a passage of the magnetic flux. Is done. At this time, the rotor core 21 is a circular silicon steel plate 21a in which a plurality of rotor slots 23 are radially formed at predetermined intervals on the outer circumferential side of the rotor slot along the axial direction. A plurality of stacks are formed so as to be continuous, and a metal such as aluminum or copper having high conductivity is inserted into the rotor slot 23 to form the rotor conductor 25. In addition, end rings 27 are formed at both ends of the rotor conductor 25 to connect the rotor conductors to each other to form a circuit, and the rotor conductor and the end rings are generally made of aluminum which can be die casted. This applies a lot.

On the other hand, the induction motor according to the first embodiment of the present invention is formed with an insulating film 100 of a predetermined thickness in the rotor slot in order to prevent the current of the rotor conductor 25 from leaking into the steel sheet (21a). . The insulating film 100 is formed on the inner wall along the rotor slot 25 and also on the peripheral steel plate 21a around the rotor slot, whereby the current induced in the rotor conductor is transferred to the steel sheet. It is possible to reliably prevent leakage. In this case, the insulating film 100 may be formed of various materials having high insulating properties, but the present invention suggests that the insulating film is a zinc phosphate-based coating film. Because the zinc phosphate-based coating film is excellent in heat resistance compared to the general phosphate-based coating film provided in the conventional steel sheet, but will be described in detail later, but may be destroyed by high heat during the die casting process for manufacturing the rotor core 21 This is because the insulation can be reliably ensured.

Referring to the operation of the induction motor configured as described above, the alternating current is applied to the coil 15 generates a magnetic field to rotate the magnetic flux through the stator core (11), the rotating magnetic flux is a void (a By linking with the rotor conductor 25 through), a current is induced in the rotor conductor.

At this time, as shown in FIG. 4, the electric current induced in the rotor conductor 25 is caused by the insulating film 100 formed around the inner wall of the rotor slot 23 and the rotor slot of the steel plate 21a. All will flow to the end ring without leaking into the steel plate. Therefore, the stray load loss caused by leakage of current induced in the rotor conductor 25 into the steel sheet can be significantly reduced, thereby improving the efficiency of the induction motor.

Meanwhile, as described above, the manufacturing process of the rotor in which the insulation film is formed in the rotor slot in the induction motor according to the present invention will be described below.

As shown in Figure 5a, the manufacturing method of the rotor of the induction motor according to the first embodiment of the present invention is a radial in the inlet and the outer peripheral side in which the shaft is press-fitted to the center of the thin silicon steel sheet using a press mold first Punching a plurality of rotor slots formed in step (S11) is performed.

At this time, not only mechanical stress such as torsion remains in the steel sheet during the above-mentioned punching step S11, but also the electrical characteristics of the steel sheet are destroyed. In order to solve this problem, a heat treatment step (S13) is performed to apply heat treatment to the punched steel sheet to remove mechanical stress and at the same time to restore electrical characteristics.

Next, a lamination step (S15) is performed in which the heat-treated steel sheet is aligned so that the rotor slots are continuous along the axial direction and then fixed by welding or by riveting or clamping to produce a rotor iron core. At this time, the lamination step S15 may be preceded by the heat treatment step S13.

Next, an insulating film forming step (S17) of impregnating the rotor iron core with the insulating coating material for a predetermined time to form an insulating coating on the rotor slot is performed. In addition to the effect that the insulating film of the steel sheet destroyed in the punching step (S11) by the insulating film forming step (S17) is complemented, the effect that the insulating film is newly formed in the rotor slot formed along the axial direction can be achieved.

Specifically, as shown in Figure 5b, the insulating film forming step is a degreasing step (S17a) for removing various contaminants buried on the surface of the rotor core is laminated for 2 to 3 minutes using an alkaline liquid and Washing step (S17b) of washing the degreased rotor core for about 1 minute, surface adjustment of the washed rotor core for about 30 seconds (S17c), and the surface adjustment of the rotor iron core of the predetermined insulation Impregnating step (S17d) of impregnating the coating coating for 5-7 minutes to form an insulating film, washing step (S17e) of washing the impregnated rotor core again for 1 minute, and washing the completed rotor iron core approximately 10 Drying step S17f.

At this time, the insulating coating agent used in the impregnation step (S17d) is a zinc phosphate-based excellent insulation and heat resistance is composed of a functional additive having a variety of functions in a predetermined composition ratio in the aqueous solution. The insulating coating agent is formed by mixing a predetermined amount of phosphoric acid (H ₃ PO ₄ ), nitric acid (HNO ₃ ), zinc oxide (ZnO), calcium hydroxide (Ca (OH) ₂ ) by a predetermined amount, and insulating properties therein. And other additives which further double the heat resistance and the like. In the composition ratio of the insulating coating, the weight ratio of water: phosphoric acid (H ₃ PO ₄ ): nitric acid (HNO ₃ ): zinc oxide (ZnO): calcium hydroxide (Ca (OH) ₂ ): other additives is 30 to 40. %: 30-40%: 5-10%: 5-10%: 5-10%: 3-8% are shown.

Therefore, when the rotor iron core is dried after the impregnation step (S17d) is completed, a zinc phosphate-based insulating film is formed on the inner wall of the rotor slot and the surrounding steel plate.

Next, a die casting step (S19) of forming the rotor conductor and the end ring is performed by inserting the rotor iron core into a mold and injecting an aluminum melt, thereby completing the rotor of the induction motor. However, as the temperature of about 250 ° C. is applied to the rotor core in the die casting step S19, the insulating film formed on the rotor slot may be destroyed due to high heat. However, since the heat resistance of the insulating film formed in the rotor slot is high, such concern can be eliminated.

Next, FIG. 6 is a cross-sectional view schematically illustrating a structure of an induction motor according to a second embodiment of the present invention, and FIG. 7 is a cross-sectional view showing an eddy current path flowing through a rotor steel plate in the induction motor according to FIG. 6. 8 is a flowchart illustrating a method of manufacturing a rotor of an induction motor according to FIG. 6.

As shown in FIG. 6, the induction motor according to the second embodiment of the present invention also has a stator 10 and a rotor 20 that forms a concentric circle with the stator and maintains a predetermined gap a in the inner circumference of the stator. And a shaft 30 press-fitted to the center of the rotor to transmit the rotational force of the rotor to the driven shaft.

The stator 10 includes a coil 15 that receives an alternating current power to form a rotating magnetic field, and a stator iron core 11 of a magnetic material that forms a passage for magnetic flux generated by the rotating magnetic field. At this time, the stator iron core 11 is configured by stacking a plurality of circular silicon steel plate (11a) in which a plurality of stator slots 13 are formed radially on the inner circumference so that the stator slots are continuous along the axial direction, Through the stator slot 13 the coil 15 is wound in various ways.

The rotor 20 is a rotor conductor 25 for generating torque by the interaction of the current induced by the coil 15 with the magnetic flux, and a rotor iron core 21 of the magnetic body forming a passage of the magnetic flux. Is done. At this time, the rotor core 21 is a circular silicon steel plate 21a in which a plurality of rotor slots 23 are radially formed at predetermined intervals on the outer circumferential side of the rotor slot along the axial direction. A plurality of stacks are formed so as to be continuous, and a metal such as aluminum or copper having high conductivity is inserted into the rotor slot 23 to form the rotor conductor 25. In addition, end rings 27 are formed at both ends of the rotor conductor 25 to connect the rotor conductors to each other to form a circuit, and the rotor conductor and the end rings are generally made of aluminum which can be die casted. This applies a lot.

On the other hand, the induction motor according to the second embodiment of the present invention to reduce the path of the eddy current induced by the change of magnetic flux in the steel plate 21a constituting the rotor core 21, the insulating film of a predetermined thickness ( 200) is formed. The insulating film 200 is formed on both surfaces of the steel sheet 21a, thereby ensuring interlayer insulation between the steel sheet and the steel sheet. In this case, the insulating film 200 may be formed of various materials having high insulating properties, but the present invention suggests that the insulating film is a zinc phosphate-based coating film. Because the zinc phosphate-based coating film is excellent in heat resistance compared to the general phosphate-based coating film provided in the conventional steel sheet, but will be described in detail later, but may be destroyed by high heat during the die casting process for manufacturing the rotor core 21 This is because the insulation can be reliably ensured.

Referring to the operation of the induction motor configured as described above, the alternating current is applied to the coil 15 generates a magnetic field to rotate the magnetic flux through the stator core (11), the rotating magnetic flux is a void (a By linking with the rotor conductor 25 through), a current is induced in the rotor conductor.

At this time, as shown in Figure 7, the eddy current is induced by the rotating magnetic flux in the steel plate 21a of the rotor iron core, the eddy current flows along the path shown by the dotted line. At this time, as the zinc phosphate-based insulating film 200 is formed between the steel sheet 21a and the steel sheet, it is possible to prevent the eddy current path formed in any steel sheet from crossing to another adjacent steel sheet. Therefore, the eddy current path induced in the steel sheet 21a is shortened, and as a result, the resistance due to the steel sheet is reduced, and the iron loss is significantly reduced.

Meanwhile, as described above, the manufacturing process of the rotor in which the insulation coating is formed on the steel plate of the rotor core in the induction motor according to the present invention will be described below.

As shown in Figure 8, the manufacturing method of the rotor of the induction motor according to the second embodiment of the present invention is a radial in the inlet and the outer peripheral side in which the shaft is press-fitted to the center of the thin silicon steel sheet using a press die first Punching a plurality of rotor slots formed in step (S21) is performed. At this time, the phosphate-based insulating film previously coated on the steel sheet during the aforementioned punching step (S21) is mostly destroyed in the vicinity by mechanical stress such as torsion, rotor slot, and torsion.

Next, a heat treatment step (S23) is performed to apply heat treatment to the punched steel sheet in order to remove the torsion and residual mechanical stress to the steel sheet and restore electrical characteristics.

Next, an insulating film forming step (S25) of impregnating the heat-treated steel sheet with a predetermined insulating coating agent for a predetermined time to form an insulating film on both sides of the steel sheet is performed. In addition to the effect that the insulating film of the steel sheet destroyed in the punching step (S21) by the insulating film forming step (S25) is supplemented, a new insulating film is added to the existing insulating film to ensure the insulation more reliably. In this case, the insulating film forming step may include a degreasing step of removing various contaminants on the surface of the rotor steel sheet using alkaline liquid, a washing step of washing the degreasing rotor steel sheet, and washing with water. Surface adjustment of the rotor steel plate, impregnation step of impregnating the surface-adjusted rotor steel plate with a predetermined insulating coating agent for 5 to 7 minutes to form an insulating film, and washing with water to wash the impregnated rotor steel plate again. And drying the washed steel plate, which is as shown in FIG. 5B.

At this time, the insulating coating agent used in the impregnation step is also zinc phosphate-based excellent in insulation and heat resistance, the composition ratio of water: phosphoric acid (H ₃ PO ₄ ): nitric acid (HNO ₃ ): zinc oxide (ZnO): calcium hydroxide The weight ratio of (Ca (OH) ₂ ): other additives is 30 to 40%: 30 to 40%: 5 to 10%: 5 to 10%: 5 to 10%: 3 to 8%.

Therefore, when the steel sheet is dried after the impregnation step is completed, a zinc phosphate-based insulating film is formed on both sides of the steel sheet.

Next, after removing the insulating film formed in the indentation hole and the rotor slot of the steel sheet, the rotor slot is aligned to be continuous along the axial direction and then fixed by welding or fixed by riveting or clamping. A lamination step S27 is performed to produce the iron core.

Next, a die casting step (S29) of forming the rotor conductor and the end ring is performed by inserting the rotor iron core into the mold and injecting aluminum melt, thereby completing the rotor of the induction motor. However, as the temperature of about 250 ° C. is applied to the rotor iron core in the die casting step S29, the insulating film formed on the steel sheet may be destroyed due to high heat. However, since the heat resistance of the insulating film formed on the steel sheet is high, such concern can be eliminated.

Next, FIG. 9 is a cross-sectional view schematically illustrating a structure of an induction motor according to a third embodiment of the present invention, and FIG. 10 is a cross-sectional view showing an eddy current path flowing through a stator steel plate in the induction motor according to FIG. 9. 11 is a flowchart illustrating a stator manufacturing method of an induction motor according to FIG. 9.

As shown in FIG. 9, the induction motor according to the third embodiment of the present invention also has a stator 10 and a rotor 20 which forms a concentric circle with the stator and maintains a predetermined gap a in the inner circumference of the stator. And a shaft 30 press-fitted to the center of the rotor to transmit the rotational force of the rotor to the driven shaft.

The stator 10 includes a coil 15 that receives an alternating current power to form a rotating magnetic field, and a stator iron core 11 of a magnetic material that forms a passage for magnetic flux generated by the rotating magnetic field. At this time, the stator iron core 11 is configured by stacking a plurality of circular silicon steel plate (11a) in which a plurality of stator slots 13 are formed radially on the inner circumference so that the stator slots are continuous along the axial direction, Through the stator slot 13 the coil 15 is wound in various ways.

The rotor 20 is a rotor conductor 25 for generating torque by the interaction of the current induced by the coil 15 with the magnetic flux, and a rotor iron core 21 of the magnetic body forming a passage of the magnetic flux. Is done. At this time, the rotor core 21 is a circular silicon steel plate 21a in which a plurality of rotor slots 23 are radially formed at predetermined intervals on the outer circumferential side of the rotor slot along the axial direction. A plurality of stacks are formed so as to be continuous, and a metal such as aluminum or copper having high conductivity is inserted into the rotor slot 23 to form the rotor conductor 25. In addition, end rings 27 are formed at both ends of the rotor conductor 25 to connect the rotor conductors to each other to form a circuit, and the rotor conductor and the end rings are generally made of aluminum which can be die casted. This applies a lot.

On the other hand, the induction motor according to the third embodiment of the present invention is an insulating film 300 of a predetermined thickness on the steel sheet so as to reduce the path of the eddy current induced by the change of magnetic flux in the steel plate (11a) constituting the stator iron core (11) ) Is formed. The insulating film 300 is formed on both sides of the steel sheet (11a), thereby ensuring the interlayer insulation between the steel sheet and the steel sheet. In this case, the insulating film 300 may be formed of various materials having high insulating properties, but the present invention suggests that the insulating film is a zinc phosphate-based coating film. This is because the zinc phosphate-based coating film is excellent in various properties such as heat resistance as well as insulation compared to the general phosphate coating film provided in the conventional steel sheet.

Referring to the operation of the induction motor configured as described above, the alternating current is applied to the coil 15 generates a magnetic field to rotate the magnetic flux through the stator core (11), the rotating magnetic flux is a void (a By linking with the rotor conductor 25 through), a current is induced in the rotor conductor.

At this time, as shown in Figure 10, the eddy current is induced by the rotating magnetic flux in the steel plate (11a) of the stator iron core, this eddy current flows along the path shown by the dotted line. At this time, as the zinc phosphate-based insulating film 300 is formed between the steel sheet 11a and the steel sheet, it is possible to prevent the eddy current path formed in any steel sheet from crossing to another adjacent steel sheet. Therefore, the eddy current path induced in the steel sheet 11a may be shortened, and as a result, the resistance due to the steel sheet is reduced, and the iron loss is significantly reduced.

On the other hand, as described above, in the induction motor according to the present invention will be described in detail the manufacturing process of the stator in which the insulating film is formed on the steel plate of the stator iron core.

As shown in Figure 11, the stator manufacturing method of the induction motor according to the third embodiment of the present invention first by punching a plurality of stator slots formed radially on the inner peripheral side of the annular silicon steel sheet using a press die ( S31) is performed. At this time, the phosphate-based insulating film previously coated on the steel sheet during the above-mentioned punching step (S31) is mostly destroyed in the surroundings not only by the stator slot but also by mechanical stress such as torsion.

Next, a heat treatment step S33 is performed to apply heat treatment to the punched steel sheet in order to remove the torsion and residual mechanical stress to the steel sheet and restore electrical characteristics.

Next, an insulating film forming step (S35) of impregnating the heat-treated steel sheet with a predetermined insulating coating agent for a predetermined time to form an insulating film on both surfaces of the steel sheet is performed. In addition to the effect that the insulating film of the steel sheet destroyed in the punching step (S31) by the insulating film forming step (S35) is supplemented, a new insulating film is added to the existing insulating film to achieve an effect that can more surely ensure the insulation Can be. At this time, the insulating film forming step (S35) is a degreasing step of removing various contaminants buried on the surface of the stator steel plate using alkaline liquid, a washing step of washing the degreased stator steel plate with water, and a washed stator steel plate. Surface-adjusting step, impregnating step of impregnating the surface-adjusted stator steel plate with a predetermined insulating coating agent for 5-7 minutes to form an insulating film, washing step of washing the impregnated stator steel plate again with water, and washing with water Drying the stator steel plate, which is as shown in Figure 5b.

At this time, the insulating coating agent used in the impregnation step is also zinc phosphate-based excellent in insulation and heat resistance, the composition ratio of water: phosphoric acid (H ₃ PO ₄ ): nitric acid (HNO ₃ ): zinc oxide (ZnO): calcium hydroxide The weight ratio of (Ca (OH) ₂ ): other additives is 30 to 40%: 30 to 40%: 5 to 10%: 5 to 10%: 5 to 10%: 3 to 8%.

Therefore, when the steel sheet is dried after the impregnation step is completed, a zinc phosphate-based insulating film is formed on both sides of the steel sheet.

Next, after removing the insulating film formed on the stator slot of the steel sheet, the stator slots are aligned so as to be continuous along the axial direction and then fixed by welding or by riveting or clamping to produce a stator iron core. S37 is performed to complete the stator of the induction motor.

So far, the present invention has been described with reference to preferred embodiments thereof, and one of ordinary skill in the art to which the present invention pertains may implement the modified embodiment within the essential technical scope of the present invention. Here, the essential technical scope of the present invention is shown in the claims, and the modified forms within the equivalent range will be construed as being included in the present invention.

The induction motor and the method of manufacturing the rotor and the stator according to the present invention provides the following effects.

First, according to the present invention, as the zinc phosphate-based insulating film having excellent insulation and heat resistance is formed in the rotor slot of the rotor iron core, it is possible to prevent the drift load loss in which current induced in the rotor conductor leaks to the steel sheet. Due to this, the efficiency of the induction motor can be improved.

Second, according to the present invention, as the zinc phosphate-based insulating film having excellent insulation and heat resistance is formed on the steel sheet constituting the rotor iron core or the stator iron core, the eddy current path formed on the steel sheet is shortened, thereby reducing the iron loss. Can improve the efficiency.

Claims (15)

A stator iron core configured by stacking a plurality of stator slots radially formed at predetermined intervals such that the stator slots are continuous along the axial direction; A coil wound around the stator slot to form a rotating magnetic field when AC power is applied; Concentric circles with the stator iron core, a plurality of rotor slots are formed by stacking a plurality of steel sheets radially formed at a predetermined interval so that the rotor slots are continuous along the axial direction, the rotor in the rotor slot A rotor iron core having an insulating film formed therein to prevent leakage of current from the slot; An induction motor provided in the rotor slot and including a rotor conductor that generates torque by current induced from the coil. The method of claim 1, The insulating film is an induction motor, characterized in that the zinc phosphate-based coating film. A stator iron core configured by stacking a plurality of stator slots radially formed at predetermined intervals such that the stator slots are continuous along the axial direction; A coil wound around the stator slot to form a rotating magnetic field when AC power is applied; Concentric circles with the iron core of the stator, a plurality of rotor slots are formed by stacking a plurality of radially formed radially at a predetermined interval so that the rotor slot is continuous along the axial direction, interlayer insulation between the steel sheets A rotor iron core on which an insulating coating layer can be secured; An induction motor provided in the rotor slot, the rotor conductor including a rotor field in which torque is generated by current induced from the coil. The method of claim 3, wherein The insulating film is an induction motor, characterized in that the zinc phosphate-based coating film. A plurality of stator slots are formed by stacking a plurality of steel sheets radially formed at predetermined intervals such that the stator slots are continuous along the axial direction, and a stator iron core having an insulating film formed therebetween to secure interlayer insulation therebetween. ; A coil wound around the stator slot to form a rotating magnetic field when AC power is applied; A rotor iron core concentric with the stator iron core and configured by stacking a plurality of steel sheets in which a plurality of rotor slots are radially formed at predetermined intervals such that the rotor slots are continuous along the axial direction; An induction motor provided in the rotor slot and including a rotor conductor that generates torque by a current drawn from the coil. The method of claim 5, The insulating film is an induction motor, characterized in that the zinc phosphate-based coating film. A punching step of forming a rotor slot at a predetermined position of a thin steel plate by using a press die; Laminating step of manufacturing the rotor iron core by aligning the punched steel sheet so that the rotor slot is continuous along the axial direction; An insulating film forming step of forming an insulating film in the rotor slot by impregnating the rotor iron core with an insulating film coating agent for a predetermined time; And a die casting step of forming the rotor conductor and the end ring by applying pressure after inserting the rotor iron core into a mold and injecting an aluminum melt. The method of claim 7, wherein The insulating coating agent is a rotor manufacturing method of the induction motor, characterized in that the zinc phosphate coating agent. The method of claim 8, The insulating coating agent has a weight ratio of water: phosphoric acid (H ₃ PO ₄ ): nitric acid (HNO ₃ ): zinc oxide (ZnO): calcium hydroxide (Ca (OH) ₂ ): other additives: 30-40%: 30-40% 5 to 10%: 5 to 10%: 5 to 10%: 3 to 8%. A punching step of forming a rotor slot at a predetermined position of a thin steel plate by using a press die; An insulating film forming step of forming an insulating film on both sides of the steel sheet by impregnating the punched steel sheet with an insulating film coating agent for a predetermined time; Stacking the impregnated steel sheet so as to align the rotor slots along the axial direction to produce a rotor iron core; And a die casting step of forming the rotor conductor and the end ring by applying pressure after inserting the rotor iron core into a mold and injecting an aluminum melt. The method of claim 10, The insulating coating agent is a rotor manufacturing method of the induction motor, characterized in that the zinc phosphate coating agent. The method of claim 11, The insulating coating agent has a weight ratio of water: phosphoric acid (H ₃ PO ₄ ): nitric acid (HNO ₃ ): zinc oxide (ZnO): calcium hydroxide (Ca (OH) ₂ ): other additives: 30-40%: 30-40% 5 to 10%: 5 to 10%: 5 to 10%: 3 to 8%. A punching step of forming a stator slot at a predetermined position of a thin steel sheet using a press die; An insulating film forming step of forming an insulating film on both sides of the steel sheet by impregnating the punched steel sheet with an insulating film coating agent for a predetermined time; A stator manufacturing method of an induction motor including a lamination step of manufacturing a stator iron core by aligning the impregnated steel sheet so that the stator slots are continuous in the axial direction. The method of claim 13, The insulating coating agent is a method of manufacturing a stator of an induction motor, characterized in that the zinc phosphate-based coating agent. The method of claim 14, The insulating coating agent has a weight ratio of water: phosphoric acid (H ₃ PO ₄ ): nitric acid (HNO ₃ ): zinc oxide (ZnO): calcium hydroxide (Ca (OH) ₂ ): other additives: 30-40%: 30-40% 5 to 10%: 5 to 10%: 5 to 10%: 3 to 8%.