WO2019176107A1

WO2019176107A1 - Induction motor rotor and induction motor

Info

Publication number: WO2019176107A1
Application number: PCT/JP2018/010603
Authority: WO
Inventors: 樹小野; 仁明大熊; 宏紀立木
Original assignee: 三菱電機株式会社
Priority date: 2018-03-16
Filing date: 2018-03-16
Publication date: 2019-09-19
Also published as: JP6667731B2; CN111903037B; JPWO2019176107A1; CN111903037A

Abstract

This induction motor rotor (60) is equipped with a rotor core (61) and conductor bars (63) disposed in respective slots formed in the rotor core (61). The induction motor rotor (60) is characterized by being provided with: end rings (64) disposed at axial ends of the rotor core (61) so as to electrically connect the conductor bars (63) to each other; insulation sheets (66) which are insulating members disposed between the conductor bars (63) and wall surfaces (61a) forming the slots; and die-cast members (65) which are non-magnetic conductor materials disposed between the wall surfaces (61a) and the insulation sheets (66).

Description

Induction motor rotor and induction motor

The present invention relates to an induction motor rotor that is an induction type rotating electric machine and an induction motor including the rotor.

Induction type rotating electrical machines are often used because they have the advantages of a robust structure and a lower manufacturing cost than a synchronous rotating electrical machine and can be started directly connected to a power source. Hereinafter, the induction type rotating electrical machine may be referred to as an induction machine.

In an induction machine, a rotating magnetic field is generated when an alternating current flows through the winding of the stator, and this rotating magnetic field acts on the secondary conductor of the rotor, thereby generating an electromotive force on the secondary conductor of the rotor. Current flows. The secondary conductor of the rotor is composed of an end ring provided on the rotor core and a rotor bar inserted into the rotor core. When an electromagnetic force based on Fleming's left-hand rule is generated between the current and the rotating magnetic field, the secondary conductor is pulled in the direction of the rotating magnetic field, and the rotor rotates. In the induction machine configured as described above, the rotational efficiency of the rotor can be increased by reducing the resistance of the path of the current flowing through the secondary conductor.

By using copper having a relatively low resistivity as the material of the rotor bar, the resistance of the secondary conductor may be lowered and the rotation efficiency may be improved.

Rotational efficiency of the induction machine can also be improved by reducing cross current loss caused by unnecessary current flowing through the rotor. Cross current loss means that when a skew is applied to the secondary conductor, a potential difference between the secondary conductor and the rotor core causes a current that should not flow between the secondary conductor and the rotor core. It is a loss caused by flowing.

As a method of reducing the cross current loss, as disclosed in Patent Document 1, an insulating agent is immersed in a wall surface forming a slot provided in a rotor core, and then the insulating agent is cured to be applied to the wall surface. A method of providing an insulating layer is conceivable. By providing the insulating layer, the insulation resistance between the wall forming the slot and the rotor bar is increased, current flowing from the rotor bar toward the rotor core is suppressed, and cross current loss is reduced.

JP 2001-25222 A

However, in order to form the insulating layer on the wall surface that forms the slot of the rotor core by the method disclosed in Patent Document 1, a tank for applying the insulating agent to the rotor core and the insulating agent are cured. And a furnace are needed. Therefore, if the size of the rotor core is increased, these tanks and furnaces must be enlarged. Therefore, it is necessary to manufacture tanks and furnaces corresponding to the size of the rotor core, and the production efficiency of the rotor is reduced. There was a problem.

The present invention has been made in view of the above, and an object of the present invention is to obtain a rotor of an induction motor that can improve production efficiency while suppressing a decrease in rotational efficiency due to crossflow loss.

In order to solve the above-described problems and achieve the object, the rotor of the induction motor of the present invention includes a rotor core and a conductor bar provided in each of a plurality of slots formed in the rotor core. A rotor of an induction motor is provided at an end portion in the axial direction of a rotor core, and an insulating member provided between an end ring that electrically connects a plurality of conductor bars to each other, and a wall surface that forms a slot and the conductor bars. And a nonmagnetic conductor material provided between the wall surface and the insulating member.

The rotor of the induction motor according to the present invention has an effect that production efficiency can be improved while suppressing a decrease in rotational efficiency due to cross current loss.

The figure which shows the structure of the induction motor which concerns on Embodiment 1 of this invention. The perspective view of the rotor of the induction motor shown in FIG. 1 is a perspective view of a rotor core of the induction motor shown in FIG. The figure which shows the state in inserting the insulation sheet in the slot of the rotor core shown in FIG. The figure which expands and shows the insulating sheet inserted in the slot of the rotor core shown in FIG. The figure which shows the state in which the conductor bar is inserted inside the insulating sheet shown in FIG. The figure which shows the state which provided the end ring in each of the both ends of the rotor core shown in FIG. External view of the conductor bar used for the rotor with which the induction motor which concerns on Embodiment 2 of this invention is provided The perspective view of the rotor iron core in which the conductor bar shown in FIG. 8 was inserted Sectional drawing of a rotor provided with the rotor core and conductor bar shown in FIG. The figure which shows the state which provided the end ring in each of the both ends of the rotor core shown in FIG. Sectional view of the rotor core, end ring and conductor bar shown in FIG. The block diagram of the insulating member provided in the conductor bar which concerns on the 1st modification of Embodiment 2 of this invention. The block diagram of the insulation member provided in the conductor bar which concerns on the 2nd modification of Embodiment 2 of this invention. The block diagram of the insulating member provided in the conductor bar which concerns on the 3rd modification of Embodiment 2 of this invention. External view of conductor bar used for rotor provided in induction motor according to embodiment 3 of the present invention

Hereinafter, a rotor and an induction motor of an induction motor according to an embodiment of the present invention will be described in detail based on the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing the structure of an induction motor according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the rotor of the induction motor shown in FIG. FIG. 3 is a perspective view of the rotor core of the induction motor shown in FIG.

FIG. 1 shows a one-side cross section of the induction motor 100 according to the first embodiment. In FIG. 1, the axial direction that is the direction in which the central axis AX of the rotor core 61 extends is the direction indicated by the arrow D1 in FIG. The circumferential direction of the central axis AX of the rotor core 61 is the direction indicated by the arrow D2 in FIG.

The induction motor 100 is provided on a bottomed cylindrical frame 11, an end plate 12 that closes an opening of the frame 11, an annular stator 10 that is fixed to the inner peripheral surface of the frame 11, and a bottom of the frame 11. And a bearing 2 provided on the end plate 12. The housing 3 is constituted by the frame 11 and the end plate 12.

The induction motor 100 also includes a cylindrical rotor 60 provided inside the stator 10 and a shaft 70 that is rotatably supported by the bearing 1 and the bearing 2 and provided inside the rotor 60.

The rotor 60 includes a cylindrical rotor core 61 configured by laminating a plurality of steel plates in the axial direction. A plurality of slots 62 are formed in the rotor core 61. The plurality of slots 62 are formed side by side in the circumferential direction near the outer peripheral surface of the rotor core 61, and each of the plurality of slots 62 extends in the axial direction and penetrates from one end portion of the rotor core 61 to the other end portion. Each of the plurality of slots 62 is skewed in the circumferential direction.

Further, the rotor 60 includes a conductor bar 63 provided inside the plurality of slots 62 and an end ring 64 that is an end-ring ring that is provided at each of both axial ends of the rotor core 61 and connects the plurality of conductor bars 63. And a die-cast member 65 that is a nonmagnetic conductor material.

Examples of the material of the conductor bar 63 include nonmagnetic conductor materials such as aluminum, aluminum alloy, copper, and copper alloy.

Next, a method for manufacturing the rotor 60 will be described with reference to FIGS. 4 is a view showing a state in which an insulating sheet is being inserted into the slot of the rotor core shown in FIG. FIG. 5 is an enlarged view showing the insulating sheet inserted into the slot of the rotor core shown in FIG. FIG. 6 is a view showing a state in which a conductor bar is being inserted inside the insulating sheet shown in FIG. FIG. 7 is a view showing a state in which end rings are provided at both ends of the rotor core shown in FIG.

When the rotor 60 is manufactured, first, the rotor core 61 and the V-shaped insulating sheet 66 as viewed along the axial direction are manufactured.

The insulating sheet 66 is formed into a V shape as shown in FIG. 4 by folding an insulating sheet made of a material having high heat resistance such as meta-aramid fiber and mica.

Next, by folding back one end portion of the manufactured insulating sheet 66 in the axial direction, a folded portion 661 having a collar shape is formed on the insulating sheet 66. The insulating sheet 66 on which the folded portion 661 is formed is inserted into the slot 62. The vertex of the V shape of the insulating sheet 66 is directed to the central axis side. A similar folded portion 661 is also provided at the other end portion of the insulating sheet 66 inserted into the slot 62.

Next, as shown in FIG. 6, a rod-shaped conductor bar 63 is inserted inside the insulating sheet 66 inserted into the slot 62. By inserting the conductor bar 63 into the insulating sheet 66, the inner surface of the insulating sheet 66 is pushed by the conductor bar 63, and the insulating sheet 66 expands toward the wall surface that forms the slot 62.

By providing the folded portion 661, when the conductor bar 63 is inserted inside the insulating sheet 66 inserted into the slot 62, the folded portion 661 can be attached to the rotor core 61 even if the insulating sheet 66 contacts the conductor bar 63. The insulation sheet 66 is restrained from moving in the axial direction by being caught at the end. Therefore, the production efficiency of the rotor 60 is improved as compared with the case where the folded portion 661 is not provided.

Thereafter, as shown in FIG. 7, using the nonmagnetic conductor material as a die-cast material, end rings 64 are provided on the one end surface 61 b and the other end surface 61 c in the axial direction of the rotor core 61, respectively. A die-cast member 65 is provided. The two end rings 64 and the die cast member 65 are collectively formed by die casting.

The end ring 64 has a function of electrically connecting the plurality of conductor bars 63 to each other and a function of fixing each of the plurality of conductor bars 63 to the rotor core 61.

The die-cast member 65 is provided in a gap between the wall surface 61 a forming the slot 62 and the insulating sheet 66 and a gap between the conductor bar 63 and the insulating sheet 66.

As a method of forming the secondary conductor in the slot 62, a method of forming the secondary conductor by die casting by pouring molten die-cast material into the slot 62 without providing the conductor bar 63 in advance in the slot 62. There is. As described above, when the secondary conductor is formed in the slot 62 in a state where the conductor bar 63 is not inserted inside the insulating sheet 66, the end portion in the axial direction of the insulating sheet 66 is buckled by the die casting pressure. The axial end portion of the buckled insulating sheet 66 may enter the slot 62.

When the insulating sheet 66 is buckled in this way, a portion where the insulating sheet 66 does not exist is formed between the wall surface 61 a forming the slot 62 and the die cast member 65 provided in the slot 62. Therefore, the insulation resistance between the rotor core 61 and the die cast member 65 is lower than that when the insulating sheet 66 is not buckled. Therefore, the cross current loss generated in the rotor 60 shows a larger value than the cross current loss generated in the rotor 60 when the insulating sheet 66 is not buckled.

Further, there is a possibility that the slot 62 is blocked by the buckled insulating sheet 66. In this case, passage of the die-cast material to the slot 62 is hindered, and there may be a portion where the die-cast material is not filled in the space inside the insulating sheet 66. In this case, the rotation efficiency of the rotor 60 is lower than when the insulating sheet 66 is not buckled.

According to the rotor 60 according to the first embodiment, since the conductor bar 63 is provided on the inner side of the insulating sheet 66, the insulating sheet 66 is attached to the conductor bar 63 even when die-cast pressure is applied to the insulating sheet 66. Since it is supported, it can suppress that the insulating sheet 66 buckles.

Therefore, even after the die cast member 65 is formed, the insulating sheet 66 can be interposed between the conductor bar 63 and the rotor core 61. Therefore, the insulation resistance between the rotor core 61 and the die-cast member 65 is higher than that when the insulating sheet 66 is buckled. As a result, the cross current loss generated in the rotor 60 is lower than the cross current loss generated in the rotor 60 when the insulating sheet 66 is buckled.

Moreover, since the passage of the die-cast material to the slot 62 is not hindered, it is possible to suppress the occurrence of a portion not filled with the die-cast material in the space inside the insulating sheet 66. Therefore, as compared with the case where the insulating sheet 66 is buckled, the rotation efficiency of the rotor 60 is improved, and the conductor bar 63 inserted inside the insulating sheet 66 can be firmly fixed with the die-cast material.

Further, according to the first embodiment, the step of providing an insulating layer on the wall surface 61a forming the slot 62 becomes unnecessary, so that the tank for applying the insulating agent to the rotor core 61 and the insulating agent are hardened and insulated. A furnace for forming the agent layer becomes unnecessary. Therefore, even when the size of the rotor core 61 is increased, it is not necessary to manufacture a tank and a furnace corresponding to the increased size of the rotor 60, and the production efficiency of the rotor 60 is improved.

Further, in order to form the insulating layer, it is necessary to heat the rotor core 61, and this heating takes a long time. According to the rotor 60 according to the first embodiment, the process of forming the insulating layer on the wall surface 61a that forms the slot 62 is not required, so that the production efficiency of the rotor 60 is greatly improved.

As the material of the conductor bar 63, by selecting a material having a lower resistivity than a material having a low melting point among nonmagnetic conductor materials, the rotational efficiency of the rotor 60 can be improved. In addition, the material used for die casting is selected with priority given to a material having a low melting point over a material having a low resistivity among nonmagnetic conductor materials, thereby improving the production efficiency of the rotor 60. Can do. Therefore, for example, by selecting copper as the material of the conductor bar 63 and selecting aluminum as the material of the end ring 64 and the die cast member 65, the rotational efficiency and production efficiency of the rotor 60 can be improved.

Embodiment 2. FIG.
FIG. 8 is an external view of a conductor bar used in the rotor included in the induction motor according to Embodiment 2 of the present invention. In the conductor bar 63 used in the induction motor 100 of the second embodiment, a portion of the surface of the conductor bar 63 near the center in the axial direction is covered with the insulating coating 90 and a portion near the end in the axial direction is covered with the insulating coating 9. Not covered.

Examples of the material of the insulating coating 90 include materials having high heat resistance such as silica and mica. For example, a material having high heat resistance is sprayed on a portion near the center in the axial direction in the surface of the conductor bar 63, and then the conductor bar 63 is heated and dried to form the insulating coating 90. . The method of forming the insulating coating 90 is not limited to this, and may be electrodeposition coating in which the insulating coating 90 is formed on the surface of the conductor bar 63 by electrodeposition using an aqueous solution containing a material having high heat resistance as an electrolytic solution.

FIG. 9 is a perspective view of the rotor core in which the conductor bar shown in FIG. 8 is inserted. 10 is a cross-sectional view of a rotor including the rotor core and the conductor bar shown in FIG. FIG. 11 is a view showing a state in which end rings are provided at both ends of the rotor core shown in FIG. 12 is a cross-sectional view of the rotor core, end ring, and conductor bar shown in FIG.

9 and 10 show a state in which the conductor bar 63 is inserted into the plurality of slots 62 so that the center position of the axial conductor bar 63 coincides with the center position of the rotor core 61 in the axial direction. .

10, the width of the portion where the insulating coating 90 is formed in the length of the conductor bar 63 in the axial direction is indicated by Y. A width from one end surface to the other end surface of the rotor core 61 in the axial direction is indicated by X. In the rotor 60A of the second embodiment, the axial width Y of the insulating coating 90 is set to a value shorter than the axial width X of the rotor core 61 in consideration of assembly tolerances.

The reason for configuring in this way is that a plurality of conductor bars 63 need to be electrically connected by end rings 64 as shown in FIGS. The end ring 64 is formed by die casting using a die cast material after the conductor bar 63 is inserted into the slot 62.

Due to assembly tolerances of components constituting the rotor 60, manufacturing errors when forming the insulating coating 90, etc., insulation is performed on the portion of the conductor bar 63 inserted into the rotor core 61 that protrudes from the end of the rotor core 61. When the end ring 64 is provided in a state where the film 90 is formed, the plurality of conductor bars 63 are separated from each other, and the secondary resistance is increased. Due to the increase in the secondary resistance, the rotation efficiency of the rotor 60 is lowered, and the output of the induction motor 100 is lowered.

In the induction motor 100 according to the second embodiment, since the portion near the end of the conductor bar 63 is not covered with the insulating film 90, the plurality of conductor bars 63 are electrically connected when the end ring 64 is provided. Thus, an increase in secondary resistance is suppressed.

In addition, according to the induction motor 100 according to the second embodiment, the same effect as that of the first embodiment can be obtained, and it is not necessary to insert the insulating sheet 66 into the slot 62. Therefore, the slot of the rotor core 61 can be obtained. Even when the cross-sectional area 62 is small, the manufacture of the rotor 60A is facilitated.

In addition, since the heat capacity of the conductor bar 63 is smaller than the heat capacity of the rotor core 61, the heat capacity is smaller than when the rotor core 61 is placed in a furnace and an insulating layer is provided on the wall surface 61 a forming the slot 62. The insulating coating 90 that is an insulating layer can be provided on the conductor bar 63 in a short time using a furnace. Therefore, in the second embodiment, the production efficiency of the rotor 60A can be increased as compared with the case where the rotor core 61 is placed in the furnace.

FIG. 13 is a configuration diagram of an insulating member provided in a conductor bar according to a first modification of the second embodiment of the present invention. The conductor bar 63 shown in FIG. 13 is provided with a plurality of insulating members 90A. The plurality of insulating members 90A are provided apart from each other in the axial direction.

Each of the plurality of insulating members 90A may be provided on the conductor bar 63 by spraying a material having high heat resistance after applying a plurality of masks that are separated from each other in the axial direction on the surface of the conductor bar 63. Alternatively, a material having high heat resistance may be provided on the conductor bar 63 by electrodeposition coating.

Further, each of the plurality of insulating members 90A may be formed by fitting an insulating member formed in a ring shape using a material having high heat resistance to the conductor bar 63.

FIG. 14 is a configuration diagram of an insulating member provided in a conductor bar according to a second modification of the second embodiment of the present invention. The conductor bar 63 shown in FIG. 14 is provided with a spiral insulating member 90B. The insulating member 90B may be provided on the conductor bar 63 by performing spiral coating on the surface of the conductor bar 63 and spray-coating a material having high heat resistance. It may be provided on the conductor bar 63 by coating.

Further, the insulating member 90B may be formed by spirally winding a strip-shaped insulating sheet having high heat resistance around the conductor bar 63.

FIG. 15 is a configuration diagram of an insulating member provided in a conductor bar according to a third modification of the second embodiment of the present invention. The conductor bar 63 shown in FIG. 15 is provided with a knitted insulation member 90C. The insulating member 90 </ b> C may be formed by winding a knitted insulating sheet having high heat resistance around the conductor bar 63, or may be formed by attaching a knitted cylindrical body having high heat resistance to the conductor bar 63.

Since any one of the plurality of insulating members 90A, insulating members 90B, and insulating members 90C is provided on the conductor bar 63, the amount of the insulating member used can be reduced, so the manufacturing cost of the rotor 60A can be reduced. Can be reduced.

Embodiment 3 FIG.
FIG. 16 is an external view of a conductor bar used in the rotor included in the induction motor according to Embodiment 3 of the present invention. In the induction motor 100 of the third embodiment, a conductor bar 63A is used instead of the conductor bar 63 shown in FIG.

The conductor bar 63A is composed of a plurality of fine wires 63b. The plurality of thin wire members 63 b are bundled with an insulating sheet 91. The insulating sheet 91 before bundling the plurality of thin wire members 63b has a strip shape. One conductor bar 63A is formed by winding a strip-shaped insulating sheet 91 in a state where a plurality of thin wire members 63b are bundled.

In the third embodiment, the same effect as in the first embodiment can be obtained, and the slot 62 can be obtained by changing the diameter of each of the plurality of fine wire members 63b and changing the number of the thin wire members 63b used. The cross-sectional shape orthogonal to the axial direction of the conductor bar 63A can be easily changed in accordance with the cross-sectional shape orthogonal to the axial direction. Therefore, since the shape of the conductor bar 63A can be made to correspond to various types of rotor cores 61 having different cross-sectional shapes of the slots 62, the production efficiency of the rotor 60 is improved.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1, 2, bearing, 3 housing, 10 stator, 11 frame, 12 end plate, 60, 60A rotor, 61 rotor core, 61a wall surface, 61b one end surface, 61c other end surface, 62 slots, 63, 63A conductor bar, 63b fine wire material, 64 end ring, 65 die cast member, 66, 91 insulating sheet, 70 shaft, 90 insulating coating, 90A, 90B, 90C insulating member, 100 induction motor, 661 folded portion.

Claims

The rotor core,
A conductor bar provided in each of a plurality of slots formed in the rotor core;
An end ring provided at an axial end of the rotor core, and electrically connecting the plurality of conductor bars to each other;
An insulating member provided between a wall forming the slot and the conductor bar;
A nonmagnetic conductor material provided between the wall surface and the insulating member;
A rotor for an induction motor comprising:
The conductor bar material is copper,
The induction motor rotor according to claim 1, wherein each material of the nonmagnetic conductor material and the end ring is aluminum.
3. The rotor for an induction motor according to claim 1, wherein the insulating member is an insulating sheet.
4. The induction motor rotor according to claim 3, wherein a folded portion is provided at an end of the insulating member.
The rotor of an induction motor according to any one of claims 1 to 4, wherein the conductor bar is formed by bundling a plurality of wires and integrally forming the conductor bar.
3. The rotor of an induction motor according to claim 1, wherein the insulating member is an insulating film.
The rotor of an induction motor according to claim 6, wherein the width of the insulating coating in the axial direction is narrower than the width of the rotor core in the axial direction.
A rotor for an induction motor according to any one of claims 1 to 7,
A stator provided with the rotor inside,
An induction motor comprising: