JPH1198733A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the efficiency of a motor by preventing eddy current from occurring. SOLUTION: This motor has a rotor 37, a stator 38 arranged at a specified interval from the rotor 37, and a coil 139 wound on the stator 38, and the rotor 37 is equipped with end members consisting of nonmagnetic substance at both its ends, and at least either of the end members and the coil 139 is equipped with an eddy current generation suppressing part. In this case the air gap between the outside peripheral edge of the end member and the inside peripheral edge of the coil 139 becomes large, so that the number of magnetic fluxes interlinking the end members can be lessened by that amount. As a result, this can restrain an eddy current from being generated at the end member, so that the efficiency of the motor 5 can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor.

[0002]

2. Description of the Related Art Conventionally, an electric motor has a rotor and a stator disposed around the rotor. The stator includes a stator core and a stator coil wound around the stator core. Then, when a current is supplied to the stator coil and a rotating magnetic field is formed, the rotor rotates.

Further, in a synchronous motor in which magnetic poles are formed by disposing permanent magnets on a rotor, permanent magnets are disposed at a plurality of locations on a core formed by laminating electromagnetic steel sheets. ing. FIG. 2 is a sectional view of a main part of a conventional synchronous motor. In the figure, reference numeral 14 denotes a motor case, and a synchronous motor 1 is provided in the motor case 14.
5 are accommodated. The motor case 14 has a cylindrical portion 14 a and a lid portion 1 that closes one end of the cylindrical portion 14 a to form a sealed motor housing 18.
4b. A plurality of fins 24 are formed on the outer peripheral surface of the cylindrical portion 14a.

A hole is formed in the center of the bottom of the cylindrical portion 14a and in the center of the lid portion 14b, and a motor shaft 27 is provided through the hole.
The motor shaft 27 is rotatably supported by bearings 29 and 30. A concave portion 14c is formed adjacent to the hole of the lid portion 14b, and the sensor chamber 34 is formed by closing the concave portion 14c with the lid member 33.

[0005] A resolver 35 is provided in the sensor chamber 34.
The resolver 35 is provided with the motor shaft 2.
7, the position of the magnetic pole of the electric motor 15 is detected. The electric motor 15 is mounted substantially at the center in the axial direction of the motor shaft 27, and is opposed to the rotor 37 on the inner peripheral surface of the cylindrical portion of the cylindrical portion 14a. And a stator 38 fixed thereto, the stator 38 comprising a stator core 38a, and the stator core 38a.
Three-phase (U-phase, V-phase and W-phase) coils 39 wound around
Consists of

Therefore, the rotor 37 can be rotated by supplying the three-phase alternating current generated by an inverter (not shown) to each of the coils 39. The rotor 37 has a core 17 formed by laminating a plurality of electromagnetic steel sheets, and permanent magnets 55 disposed at a plurality of locations on the core 17. The permanent magnet 55 at a constant pitch in a plurality of locations.
Is arranged. The permanent magnet 55 is fixed while being pressed by end plates 56 and 57 provided at both ends, and forms a magnetic pole of the electric motor 15. Therefore, a spline 27a is provided on the outer peripheral surface of the motor shaft 27,
A spline 37a is formed on the inner peripheral surface of the rotor 37, and splines 56a and 57a are formed on the inner peripheral surfaces of the end plates 56 and 57, respectively.
7 and the end plates 56 and 57 can be spline-engaged.

On the outer peripheral surface of the motor shaft 27, a locking projection 27b is formed adjacent to the bearing 30. Therefore, the end plate 57 is pressed against the locking projection 27b, and the end plate 57, the rotor 37, and the end plate 56 are sequentially moved to the motor shaft 2.
7 and the lock nut 16 is screwed into a predetermined position of the motor shaft 27 so that the rotor 37
Can be positioned with respect to the motor shaft 27 and fixed.

The end plates 56 and 57 have an annular shape corresponding to the rotor 37 and have radial dimensions such that the outer peripheral edge is slightly inward from the outer peripheral edge of the rotor 37. Therefore, the end plates 56, 5
7, the end faces of the rotor 37 and the permanent magnet 55 can be pressed and covered, so that the rotor 37 can be prevented from moving in the axial direction.
When the permanent magnet 55 is broken, the magnet pieces can be prevented from scattering around.

On the other hand, in an induction motor using a squirrel-cage rotor as a rotor, both ends of copper rods arranged at a plurality of positions in the circumferential direction of the rotor are connected by short-circuit rings. FIG. 3 is a schematic view of a rotor of a conventional induction motor. In the figure, 101 is a rotor, 102 is a motor shaft, 103 is the rotor 10
In the outer peripheral portion of 1, a copper rod 104 is disposed at a plurality of positions in the circumferential direction at an equal pitch, and 104 is an aluminum short-circuit ring connecting both ends of each rod 103.

[0010]

However, in the case of the conventional motor, in the case of the synchronous motor 15 (FIG. 2), the rotor 3 is provided by the end plates 56 and 57.
In order to cover the end surfaces of the end plates 56, 57, the end plates 56, 57 have a radial dimension such that the outer peripheral edge is slightly inward of the outer peripheral edge of the rotor 37. The periphery approaches the coil end of the coil 39.

The end plates 56 and 57 are
Usually, it is formed of a non-magnetic metal. Therefore,
When an alternating current is supplied to the coil 39, the end plates 56, 57 are generated by a high-frequency component included in the alternating current or an induced electromotive force generated with the alternating current.
An eddy current is generated in the motor 15 and the efficiency of the motor 15 is reduced.

In the case of an induction motor, the rotor 1
No. 01, short-circuit rings 104 are disposed at both ends of the rod 103. Since the short-circuit rings 104 are usually formed of a non-magnetic metal, the short-circuit rings 1
An eddy current is generated in the electric motor 04, which lowers the efficiency of the motor. The present invention solves the problems of the conventional electric motor,
An object of the present invention is to provide an electric motor capable of suppressing generation of eddy current and increasing efficiency.

[0013]

For this purpose, an electric motor according to the present invention comprises a rotor, a stator disposed at a predetermined distance from the rotor, and a coil wound on the stator. The rotor includes an end member made of a non-magnetic material at both ends, and at least one of the end member and the coil includes an eddy current generation suppressing unit.

In another motor of the present invention,
The rotor includes a core, permanent magnets disposed at a plurality of positions in a circumferential direction of the core, and an end plate that presses the core and the permanent magnet from both sides, and the end member is the end plate, The eddy current generation suppressing part is formed on the end plate. In still another electric motor according to the present invention, the eddy current generation suppressing portion is formed in a circumferential direction of the end plate.

In still another electric motor according to the present invention, the eddy current generation suppressing portion is formed in a radial direction of the end plate. In still another motor of the present invention,
Further, the rotor includes bars disposed at a plurality of positions in a circumferential direction, and a short-circuit ring connecting both ends of the bars.
The end member is the short-circuit ring, and the eddy current generation suppressing portion is formed on the short-circuit ring.

In still another electric motor according to the present invention, the eddy current generation suppressing portion is formed by bending a coil end of the coil radially outward.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part of a synchronous motor according to a first embodiment of the present invention. In the figure, reference numeral 14 denotes a motor case, in which a synchronous motor 15 is accommodated. The motor case 14 includes a cylindrical portion 14a and a lid portion 14b that closes one end of the cylindrical portion 14a to form a closed motor housing 18. A plurality of fins 24 are formed on the outer peripheral surface of the cylindrical portion 14a.

A hole is formed at the center of the bottom of the cylindrical portion 14a and at the center of the lid portion 14b, and a motor shaft 27 is provided through the hole.
The motor shaft 27 is rotatably supported by bearings 29 and 30. A concave portion 14c is formed adjacent to the hole of the lid portion 14b, and the sensor chamber 34 is formed by closing the concave portion 14c with the lid member 33.

A resolver 35 is provided in the sensor chamber 34.
The resolver 35 is provided with the motor shaft 2.
7, the position of the magnetic pole of the electric motor 15 is detected. The electric motor 15 is mounted substantially at the center in the axial direction of the motor shaft 27, and is opposed to the rotor 37 on the inner peripheral surface of the cylindrical portion of the cylindrical portion 14a. And a stator 38 disposed at a predetermined distance from the rotor 37. The stator 38 includes a stator core 38a, and three phases (U phase, V phase) wound around the stator core 38a. And W phase).

Therefore, the rotor 37 can be rotated by supplying a three-phase AC current generated by an inverter (not shown) to each coil 139. The rotor 37 has a core 17 formed by laminating a plurality of electromagnetic steel sheets, and permanent magnets 55 disposed at a plurality of locations on the core 17.
The permanent magnets 5 are arranged at equal intervals at a plurality of locations in the circumferential direction.
5 are provided. The permanent magnet 55 is fixed in a state where it is pressed by end plates 156 and 157 as end members provided at both ends, and forms a magnetic pole of the electric motor 15. For this purpose, a spline 27a is formed on an outer peripheral surface of the motor shaft 27, a spline 37a is formed on an inner peripheral surface of the rotor 37, and splines 56a and 57a are formed on inner peripheral surfaces of the end plates 156 and 157, respectively. Rotor 37 and end plate 15
6, 157 can be spline-engaged.

A locking projection 27b is formed on the outer peripheral surface of the motor shaft 27 adjacent to the bearing 30. Therefore, the end plate 157 is pressed against the locking projection 27b,
The rotor 37 and the end plate 156 are sequentially set on the motor shaft 27, and the lock nut 16 is screwed into a predetermined portion of the motor shaft 27, whereby the rotor 37 is
Can be positioned with respect to the motor shaft 27 and fixed.

The end plates 156 and 157 have an annular shape corresponding to the rotor 37 and have a radial dimension such that the outer peripheral edge is slightly inward from the outer peripheral edge of the rotor 37. Therefore, the end plate 15
6 and 157, the end faces of the rotor 37 and the permanent magnet 55 can be pressed and covered, so that the rotor 37 can be prevented from moving in the axial direction, and when the permanent magnet 55 is broken, Can be prevented from scattering around.

Incidentally, the end plates 156, 1
In order to cover the end surfaces of the rotor 37 and the permanent magnet 55 with the end plates 156 and 157, the end plates 156 and 157 have a radial dimension such that the outer peripheral edge is slightly inward from the outer peripheral edge of the rotor 37. , 157
Is near the coil end of the coil 139. Then, the end plates 156, 157
Is usually formed of a non-magnetic metal.

Therefore, when an alternating current is supplied to the coil 139, an eddy current is generated in the end plates 156 and 157 by a high frequency component included in the alternating current or an induced electromotive force generated with the alternating current.
The efficiency of the motor 15 will be reduced. Therefore, in order to suppress generation of eddy currents in the end plates 156 and 157, annular end portions 158 and 159 as eddy current generation suppressing portions are formed in the end plates 156 and 157. Further, the coil ends 161 and 162 as the eddy current generation suppressing portions are bent radially outward.

Therefore, the end plate 156,
Since the air gap between the outer peripheral edge of the coil 139 and the inner peripheral edge of the coil 139 increases, the end plates 156, 15
The number of magnetic fluxes linking 7 can be reduced accordingly.
As a result, generation of eddy current in the end plates 156 and 157 can be suppressed, and
Efficiency can be increased.

Further, the weight of the rotor 37 can be reduced by the amount corresponding to the formation of the steps 158 and 159. Next, a second embodiment of the present invention will be described. FIG. 4 is a sectional view of a main part of a synchronous motor according to a second embodiment of the present invention. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

In this case, in order to suppress generation of eddy currents on the end plates 256 and 257 as end members, annular tapered surfaces 258 and 259 as eddy current generation suppressing portions are provided on the end plates 256 and 257. Is formed. Further, the coil ends 161 and 162 as the eddy current generation suppressing portions are bent radially outward. Accordingly, the air gap between the outer peripheral edges of the end plates 256 and 257 and the inner peripheral edge of the coil 139 increases, so that the number of magnetic fluxes linking the end plates 256 and 257 can be reduced accordingly. As a result, generation of eddy currents in the end plates 256 and 257 can be suppressed, so that the efficiency of the electric motor 15 can be increased.

Further, the weight of the rotor 37 can be reduced by the amount corresponding to the formation of the tapered surfaces 258 and 259. In addition,
In the first and second embodiments, the end plate 1
Each of 56, 157, 256, and 257 has an annular shape, but a portion covering the end face of the permanent magnet 55 may be projected radially outward, and other portions may be cut off to form a radial shape. .

Next, a third embodiment of the present invention will be described. FIG. 5 is a schematic diagram of a rotor of an induction motor according to a third embodiment of the present invention, and FIG. 6 is a side view of a rotor of the induction motor according to the third embodiment of the present invention. In the figure, reference numeral 201 denotes a rotor, 202 denotes a motor shaft, 203 denotes copper rods arranged at equal intervals at a plurality of positions in the circumferential direction on the outer peripheral portion of the rotor 201, and 204 connects both ends of each rod 203. Is a short-circuit ring made of aluminum as an end member.

In this case, in order to suppress generation of an eddy current in the short-circuit ring 204, an annular step portion 205 is formed in the short-circuit ring 204 as an eddy-current generation suppressing portion. Therefore, the air gap between the outer peripheral edge of the short-circuit ring 204 and the inner peripheral edge of the coil (not shown) increases, so that the number of magnetic fluxes interlinking the short-circuit ring 204 can be reduced accordingly. As a result, the generation of eddy current in the short-circuit ring 204 can be suppressed, so that the efficiency of the motor can be increased.

Further, the weight of the rotor 201 can be reduced by the amount corresponding to the formation of the step portion 205. Next, a fourth embodiment of the present invention will be described. FIG. 7 shows a fourth embodiment of the present invention.
It is the schematic of the rotor of the induction-type electric motor in embodiment.

In the figure, 301 is a rotor, 302 is a motor shaft, 303 is a copper rod, and 304 is a short-circuit ring as an end member. In this case, an annular tapered surface 305 as an eddy current generation suppressing portion is formed on the short-circuit ring 304 in order to suppress generation of an eddy current in the short-circuit ring 304. Therefore, the air gap between the outer peripheral edge of the short-circuit ring 304 and the inner peripheral edge of the coil (not shown) increases, so that the number of magnetic fluxes interlinking the short-circuit ring 304 can be reduced accordingly. As a result, generation of eddy current in the short-circuit ring 304 can be suppressed, so that the efficiency of the motor can be increased.

Further, the weight of the rotor 301 can be reduced by the amount corresponding to the formation of the tapered surface 305. Next, a fifth embodiment of the present invention will be described. FIG. 8 is a schematic view of a rotor of an induction motor according to a fifth embodiment of the present invention.

In the figure, 401 is a rotor, 402 is a motor shaft, 403 is a copper rod, and 404 is a short-circuit ring as an end member. In this case, in order to suppress generation of eddy current in the short-circuit ring 404 and the rod 403, annular tapered surfaces 405 as eddy-current generation suppressing portions are formed at both ends of the short-circuit ring 404 and the rod 403.

Accordingly, the air gap between the outer peripheral edge of the short-circuit ring 404 and the inner peripheral edge of the coil (not shown) increases, so that the number of magnetic fluxes interlinking the short-circuit ring 404 can be reduced accordingly. As a result, generation of eddy current in the short-circuit ring 404 can be suppressed, so that the efficiency of the motor can be increased. Also, the tapered surface 40
The weight of the rotor 401 can be reduced by an amount corresponding to the formation of the rotor 5.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0037]

As described above in detail, according to the present invention, in an electric motor, a rotor, a stator disposed at a predetermined distance from the rotor, and a coil wound on the stator are provided. And the rotor includes an end member made of a non-magnetic material at both ends, and at least one of the end member and the coil includes an eddy current generation suppression unit.

In this case, since the air gap between the outer peripheral edge of the end member and the inner peripheral edge of the coil becomes large, the number of magnetic fluxes interlinking the end member can be reduced accordingly. As a result, generation of eddy current in the end member can be suppressed, so that the efficiency of the electric motor can be increased. In another electric motor of the present invention, the rotor further includes a core, permanent magnets disposed at a plurality of locations in a circumferential direction of the core, and end plates that press the core and the permanent magnet from both sides, The end member is the end plate, and the eddy current generation suppressing portion is formed on the end plate.

In this case, since the air gap between the outer peripheral edge of the end plate and the inner peripheral edge of the coil becomes large, the number of magnetic fluxes linking the end plate can be reduced accordingly. As a result, generation of eddy current in the end plate can be suppressed, so that the efficiency of the motor can be increased. In still another electric motor according to the present invention, the rotor further includes rods arranged at a plurality of positions in a circumferential direction, and a short-circuit ring connecting both ends of the rod, and the end member includes the short-circuit ring. Wherein the eddy current generation suppressing portion is formed on the short-circuit ring.

In this case, since the air gap between the outer peripheral edge of the short-circuit ring and the inner peripheral edge of the coil becomes large, the number of magnetic fluxes interlinking the short-circuit ring can be reduced accordingly. As a result, generation of eddy current in the short-circuit ring can be suppressed, so that the efficiency of the motor can be increased. In still another electric motor according to the present invention, the eddy current generation suppressing portion is formed by bending a coil end of the coil radially outward.

In this case, since the coil end is bent radially outward, the air gap between the outer peripheral edge of the end plate and the inner peripheral edge of the coil increases. Therefore, the number of magnetic fluxes linking the end plate can be reduced accordingly. As a result, generation of eddy current in the end plate can be suppressed, so that the efficiency of the motor can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a synchronous electric motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conventional synchronous motor.

FIG. 3 is a schematic view of a rotor of a conventional induction motor.

FIG. 4 is a sectional view of a main part of a synchronous electric motor according to a second embodiment of the present invention.

FIG. 5 is a schematic view of a rotor of an induction motor according to a third embodiment of the present invention.

FIG. 6 is a side view of a rotor of an induction motor according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram of a rotor of an induction motor according to a fourth embodiment of the present invention.

FIG. 8 is a schematic view of a rotor of an induction motor according to a fifth embodiment of the present invention.

[Explanation of symbols]

 15 Electric motor 17 Core 37, 201, 301, 401 Rotor 38 Stator 55 Permanent magnet 139 Coil 156, 157, 256, 257 End plate 158, 159, 205 Step 161, 162 Coil end 203, 303, 403 Rod 204, 304, 404 Shorting ring 258, 259, 305, 405 Tapered surface

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02K 21/14 H02K 21/14 M

Claims (6)

[Claims] 1. An end member having a rotor, a stator disposed at a predetermined distance from the rotor, and a coil wound on the stator, wherein the rotor is made of a nonmagnetic material at both ends. And at least one of the end member and the coil includes an eddy current generation suppressing unit. 2. The rotor according to claim 1, wherein the rotor includes a core, permanent magnets disposed at a plurality of positions in a circumferential direction of the core, and end plates that press the core and the permanent magnet from both sides. End plate,
The electric motor according to claim 1, wherein the eddy current generation suppressing unit is formed on the end plate. 3. The electric motor according to claim 2, wherein the eddy current generation suppressing portion is formed in a circumferential direction of the end plate. 4. The electric motor according to claim 2, wherein the eddy current generation suppressing portion is formed in a radial direction of the end plate. 5. The rotor according to claim 1, wherein the rotor includes rods arranged at a plurality of positions in a circumferential direction, and a short-circuit ring connecting both ends of the rod. The electric motor according to claim 1, wherein the suppression unit is formed on the short-circuit ring. 6. The electric motor according to claim 1, wherein the eddy current generation suppressing section is formed by bending a coil end of the coil radially outward.