CN114930683A

CN114930683A - Rotating electric machine and elevator hoist

Info

Publication number: CN114930683A
Application number: CN202080091965.XA
Authority: CN
Inventors: 加岛俊大; 田中敏则; 开田健
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2022-08-19
Also published as: JP7254215B2; JPWO2021144871A1; WO2021144871A1

Abstract

In the rotating electrical machine, 3 teeth arranged continuously in the circumferential direction of the stator constitute a tooth group. Windings of the same phase are wound around 3 teeth constituting 1 tooth group, respectively. In the tooth group, among 3 teeth, the low magnetic permeability portion is provided at the tip end portion of each of the 2 teeth on the outer side while avoiding the central tooth. The low-magnetic-permeability portion has a lower magnetic permeability than the stator core.

Description

Rotating electric machine and elevator hoist

Technical Field

The present invention relates to a rotating electrical machine having a stator with teeth, and a hoisting machine for an elevator having the rotating electrical machine.

Background

Conventionally, there is known a rotating electrical machine in which an auxiliary groove is provided at a tip end portion of all teeth of a stator to reduce torque ripple (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-094901

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional rotating electric machine shown in patent document 1, the auxiliary grooves are provided at the distal end portions of all the teeth, and thereby the magnetic flux passing through all the teeth is reduced. Therefore, in the conventional rotating electric machine, there is a fear that the torque output is reduced.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a rotating electric machine and a hoisting machine for an elevator, which can reduce torque ripple and suppress reduction in torque output.

Means for solving the problems

A rotating electric machine according to the present invention includes: a rotor that rotates about an axis; and a stator facing the rotor with a gap therebetween in a radial direction of the rotor, the rotor having a rotor core and a plurality of magnetic poles provided in the rotor core and arranged in a circumferential direction of the rotor, the stator having a stator core and a plurality of windings provided in the stator core, the stator core having a back yoke and a plurality of teeth protruding from the back yoke toward the rotor, the plurality of teeth being arranged with a gap therebetween in the circumferential direction of the stator, each tooth having a tip end portion facing the rotor, the windings being wound around the teeth by concentrated winding, 3 teeth arranged continuously in the circumferential direction of the stator constitute a tooth group, 3 teeth constituting 1 tooth group are each wound with a winding of the same phase, in the tooth group, among the 3 teeth, the central teeth are avoided, and the end portions of the outer 2 teeth are provided with low-magnetic-permeability portions, and the low-magnetic-permeability portions have a lower magnetic permeability than the stator core.

Effects of the invention

According to the rotating electrical machine and the hoisting machine of the elevator of the present invention, it is possible to reduce torque ripple and suppress reduction in torque output.

Drawings

Fig. 1 is a sectional view showing a rotating electric machine according to embodiment 1.

Fig. 2 is a developed view showing a state after a portion of the stator core of fig. 1 including the U-phase tooth group is developed.

Fig. 3 is a sectional view showing a rotary electric machine of comparative example 1.

Fig. 4 is a sectional view showing a rotary electric machine of comparative example 2.

Fig. 5 is a graph showing the magnitude of torque output in each of comparative example 1, comparative example 2, and embodiment 1.

Fig. 6 is a graph showing the waveforms of the torque outputs of comparative example 1, comparative example 2, and embodiment 1.

Fig. 7 is a graph showing the magnitude of torque ripple in each of comparative example 1, comparative example 2, and embodiment 1.

Fig. 8 is a developed view showing another example of a portion including a U-phase tooth group of the rotating electric machine according to embodiment 1.

Fig. 9 is a development view showing another example of a portion including a U-phase tooth group of the rotating electric machine according to embodiment 1.

Fig. 10 is a sectional view showing a rotary electric machine according to embodiment 2.

Fig. 11 is a graph showing the magnitude of torque output of the rotating electric machine of comparative example 1, the rotating electric machine in the normal rotation of embodiment 2, and the rotating electric machine in the reverse rotation of embodiment 2.

Fig. 12 is a graph showing the waveforms of torque outputs of the rotating electric machine of comparative example 1, the rotating electric machine in the normal rotation of embodiment 2, and the rotating electric machine in the reverse rotation of embodiment 2.

Fig. 13 is a graph showing the magnitude of torque ripple in the rotating electric machine according to comparative example 1, the rotating electric machine according to embodiment 2 in the normal rotation, and the rotating electric machine according to embodiment 2 in the reverse rotation.

Fig. 14 is a sectional view showing a rotary electric machine according to embodiment 3.

Fig. 15 is a sectional view showing a rotary electric machine according to embodiment 4.

Fig. 16 is a sectional view showing a rotary electric machine according to embodiment 5.

Fig. 17 is an exploded perspective view showing a stator core of a rotating electric machine according to embodiment 6.

Fig. 18 is an exploded perspective view showing another example of a stator core of a rotating electric machine according to embodiment 6.

Fig. 19 is a vertical cross-sectional view showing an elevator hoisting machine according to embodiment 7.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings.

Embodiment mode 1

Fig. 1 is a sectional view showing a rotating electric machine according to embodiment 1. The rotating electric machine 1 includes a rotor 2 and a stator 6. The rotor 2 and the stator 6 have a common axis as a main axis. The rotor 2 is fixed to a rotary shaft 3, and the rotary shaft 3 is rotatably supported by a casing not shown. The rotor 2 and the stator 6 are disposed coaxially with the rotary shaft 3. The rotor 2 rotates integrally with the rotary shaft 3 around the main axis. Here, a direction along the radius of the rotor 2 is a radial direction, and a direction along the rotation direction of the rotor 2 is a circumferential direction.

The stator 6 faces the rotor 2 with a gap in the radial direction of the rotor 2. The stator 6 surrounds the rotor 2. The inner peripheral portion of the stator 6 faces the outer peripheral portion of the rotor 2 with a gap therebetween. The rotor 2 and the stator 6 are housed in a case.

The rotor 2 has: a rotor core 4 as a magnetic body fixed to the rotating shaft 3; and a plurality of magnetic poles 5 provided to the rotor core 4.

The rotor core 4 is a cylindrical laminated body formed by laminating a plurality of thin plates in a direction along the principal axis. Electromagnetic steel sheets are used as the plurality of thin plates constituting the rotor core 4, for example. The rotor core 4 is provided with a shaft through hole along the principal axis. The rotating shaft 3 is inserted into a shaft through hole of the rotor core 4.

The plurality of magnetic poles 5 are fixed to the outer peripheral surface of the rotor core 4. The plurality of magnetic poles 5 are arranged in the circumferential direction of the rotor core 4. The plurality of magnetic poles 5 are arranged at equal intervals in the circumferential direction of the rotor core 4. Each magnetic pole 5 is formed of a permanent magnet. The plurality of magnetic poles 5 are provided on the outer circumferential surface of the rotor core 4 such that the polarities facing the stator 6 are alternately different in the circumferential direction of the rotor 2. Therefore, the N pole of one magnetic pole 5 of the 2 magnetic poles 5 adjacent to each other in the circumferential direction of the rotor 2 is opposed to the stator 6, and the S pole of the other magnetic pole 5 is opposed to the stator 6. In this example, the number of magnetic poles 5 in the rotor 2 is 10 poles.

The stator 6 has: a stator core 7 as a magnetic body; and a plurality of windings 10 provided to the stator core 7.

The stator core 7 is a laminated body configured by laminating a plurality of thin plates in a direction along the principal axis. Electromagnetic steel sheets are used as the plurality of thin plates constituting the stator core 7, for example. Further, the stator core 7 includes: an annular back yoke 9; and a plurality of teeth 8 projecting radially inward from the back yoke 9 toward the rotor 2.

The plurality of teeth 8 are arranged at intervals in the circumferential direction of the stator 6. The plurality of teeth 8 are arranged at equal intervals in the circumferential direction of the stator 6. In this example, the stator core 7 includes 9 teeth 8. Each tooth 8 has a tip portion 83, and the tip portion 83 faces the rotor 2 with a gap therebetween. In the stator core 7, spaces formed between the plurality of teeth 8 are provided as slots.

Each of the plurality of windings 10 is wound in 1 number around each tooth 8 by concentrated winding. Thereby, a part of the winding 10 is accommodated in each slot. In this example, the stator 6 comprises 9 windings 10.

The plurality of windings 10 are connected to an ac power supply via an unshown electric wire. Thereby, three-phase alternating current is supplied to the plurality of windings 10. The three-phase alternating current includes electric power of U-phase, V-phase, and W-phase whose electric phases are different from each other by 120 °. In the stator 6, a rotating magnetic field is generated by supplying three-phase alternating current to the plurality of windings 10. In the rotor 2, a rotating magnetic field generated in the stator 6 magnetically interacts with the plurality of magnetic poles 5 to generate torque. Thereby, the rotor 2 rotates integrally with the rotary shaft 3 with respect to the stator 6.

In the

stator core

7, 3 teeth 8 that are continuous in the circumferential direction of the stator 6 constitute a tooth group 81. In this example, since the stator core 7 includes 9 teeth 8, the U-phase tooth group 81, the V-phase tooth group 81, and the W-phase tooth group 81 exist in the stator core 7 as 3 tooth groups 81.

The same-phase power is supplied to each winding 10 wound around each of the 3 teeth 8 constituting the 1 tooth group 81. That is, the same phase of the coil 10 is wound around each of the 3 teeth 8 constituting the 1 tooth group 81.

Thus, the winding 10 wound around each tooth 8 of the U-phase tooth group 81 among the 3 tooth groups 81 is a U-phase winding to which the U-phase power is supplied. The winding 10 wound around each tooth 8 of the group of teeth 81 constituting the V-phase is a V-phase winding to which power of the V-phase is supplied. The winding 10 wound around each tooth 8 of the W-phase tooth group 81 is a W-phase winding to which power of the W-phase is supplied.

In each tooth group 81, the winding direction of the coil 10 wound around each of the outer 2 teeth 8 is a forward direction, and the winding direction of the coil 10 wound around the central tooth 8 is a reverse direction.

In the present embodiment, in order to clarify the difference in the winding direction of the windings 10, the winding 10 of the U-phase is expressed as the "U-phase" when the winding direction is the forward direction, and as the "Ui-phase" when the winding direction is the reverse direction. Similarly, the V-phase winding 10 is referred to as "V-phase" when the winding direction is the forward direction, and as "Vi-phase" when the winding direction is the reverse direction. The W-phase winding 10 is represented as "W-phase" when the winding direction is a positive direction, and as "Wi-phase" when the winding direction is a negative direction.

The low-magnetic-permeability portion 82 is provided at the tip end portion 83 of each of the outer 2 teeth 8 out of the 3 teeth 8 constituting the tooth group 81. The low-magnetic-permeability portion 82 is not provided at the tip portion 83 of the central tooth 8 of the 3 teeth 8 constituting the tooth group 81. That is, in each tooth group 81, among 3 teeth 8, the low-magnetic-permeability portion 82 is provided at the distal end portion 83 of each of the 2 teeth 8 on the outer side while avoiding the central tooth 8. The low-magnetic-permeability portion 82 has a lower magnetic permeability than the stator core 7.

A groove 821 is provided at each distal end portion 83 of the outer 2 teeth 8 in each tooth group 81. The space formed by the groove 821 is the low magnetic permeability portion 82.

The groove 821 is open from the tip end portion 83 of the tooth 8 toward the rotor 2. The groove 821 is arranged in a direction along the main axis. The slots 821 are disposed over the entire range of the stator core 7 in the direction along the principal axis. In each

tooth group

81, 1 groove 821 is provided in each of the outer 2 teeth 8. In a cross section of the tooth 8 on a plane orthogonal to the main axis, the low permeability portion 82 formed by the groove 821 is rectangular in shape.

Fig. 2 is a developed view showing a state in which a portion of the stator core 7 of fig. 1 including the U-phase tooth group 81 is developed. The back yoke 9 has a plurality of back yoke members 91 arranged in a circular ring shape. In this example, the back yoke 9 includes 9 back yoke members 91. Each back yoke member 91 is disposed so that the width direction of the back yoke member 91 is along the circumferential direction of the stator 6.

Each of the back yoke members 91 is provided with 1 tooth 8. The teeth 8 protrude from the widthwise central portion of the back yoke member 91.

Contact surfaces 50 are formed at both ends of each back yoke member 91 in the width direction. In an annular state in which the plurality of back yoke members 91 are arranged in an annular shape, the abutting surfaces 50 of 2 back yoke members 91 adjacent to each other are in contact with each other. The 2 back yoke members 91 adjacent to each other are connected to each other via the joint 60 at a corner portion on the side opposite to the teeth 8. The state of the stator core 7 is changed from the annular state to the expanded state by the rotation of each back yoke member 91 about the coupling portion 60. In the expanded state of the stator core 7, the abutment surfaces 50 are separated from each other, and the plurality of back yoke members 91 are aligned in a row.

Each tooth 8 has a center line in the radial direction of the stator 6. In a cross section of the stator core 7 on a plane orthogonal to the principal axis, a straight line passing through the principal axis and through the center position in the width direction of the teeth 8 is a center line of the teeth 8. When the stator core 7 is in the expanded state, the center line CL of the center tooth 8, the center line CL1 of one outer tooth 8, and the center line CL2 of the other outer tooth 8 are parallel to each other in each tooth group 81. When the state of the stator core 7 is the expanded state, the distance between the center line CL of the center tooth 8 and the center line CL1 of one outer tooth 8 and the distance between the center line CL of the center tooth 8 and the center line CL2 of the other outer tooth 8 are equal to each other by a distance τ 0.

Each low-magnetic-permeability portion 82 formed by the groove 821 has a center line parallel to the center lines CL1, CL2 of the teeth 8 provided with the low-magnetic-permeability portion 82. Here, of the 2 low-magnetic-permeability portions 82 of each tooth group 81, the center line of the low-magnetic-permeability portion 82 provided in the tooth 8 having the center line CL1 is CL11, and the center line of the low-magnetic-permeability portion 82 provided in the tooth 8 having the center line CL2 is CL 21. When the state of the stator core 7 is the expanded state, the distance from the center line CL11 to the center line CL and the distance from the center line CL21 to the center line CL in each tooth group 81 are equal to each other by the distance τ. When the state of the stator core 7 is the expanded state, the relationship τ > τ 0 is established.

Therefore, in each tooth group 81, the low-magnetic-permeability portions 82 provided in the teeth 8 having the center line CL1 are arranged at positions farther from the center line CL than the center line CL 1. In each tooth group 81, the low-magnetic-permeability portions 82 provided on the teeth 8 having the center line CL2 are disposed at positions farther from the center line CL than the center line CL 2. That is, the low-magnetic-permeability portions 82 are disposed at positions farther from the center line CL of the central tooth 8 in the circumferential direction of the stator 6 than the center lines CL1, CL2 of the teeth 8 provided with the low-magnetic-permeability portions 82. Further, low-permeability portions 82 of 2 teeth 8 respectively disposed on the outer sides are disposed at positions geometrically symmetrical with respect to center line CL. The low-magnetic-permeability portions 82 of the outer 2 teeth 8 have the same shape.

Next, a description will be given of a rotating electric machine according to each of comparative examples 1 and 2 for comparison with the rotating electric machine 1 according to embodiment 1. Fig. 3 is a sectional view showing a rotary electric machine of comparative example 1. In the rotating electric machine 200 of comparative example 1, the grooves 821 are not provided at the distal end portions 83 of all the teeth 8. Other structures of comparative example 1 are the same as those of embodiment 1.

Fig. 4 is a sectional view showing a rotary electric machine of comparative example 2. In the rotating electric machine 300 according to comparative example 2, the low-magnetic-permeability portions 82 are provided at the distal end portions 83 of all the teeth 8 included in the stator core 7. In comparative example 2, a space portion formed by the groove 821 similar to that in embodiment 1 is provided as the low-magnetic-permeability portion 82 in each tooth 8. In comparative example 2, each tooth 8 was provided with 2 low-magnetic-permeability portions 82. The other structure of comparative example 2 is the same as comparative example 1.

Fig. 5 is a graph showing the magnitude of torque output in each of comparative example 1, comparative example 2, and embodiment 1. Fig. 5 shows magnitudes of torque outputs of the rotating electric machine in the case where the rotors 2 are rotated at the same rotational speed in comparative example 1, comparative example 2, and embodiment 1. In fig. 5, the magnitude of the torque output of comparative example 1 is set to a reference value "100", and the magnitudes of the torque outputs of comparative example 2 and embodiment 1 are normalized by the set reference value of comparative example 1.

Fig. 6 is a graph showing the waveforms of the torque outputs of comparative example 1, comparative example 2, and embodiment 1. Fig. 6 shows waveforms of torque outputs of the rotating electric machine in the case where the plurality of windings 10 are excited by the same current magnitude in comparative example 1, comparative example 2, and embodiment 1. In fig. 6, the waveform of the torque output of comparative example 1 is shown by a solid line, the waveform of the torque output of comparative example 2 is shown by a broken line, and the waveform of the torque output of embodiment 1 is shown by a one-dot chain line. The torque ripple is calculated by the difference between the maximum value and the minimum value of the waveform of the torque output.

Fig. 7 is a graph showing the magnitude of the torque ripple in each of comparative example 1, comparative example 2, and embodiment 1. In fig. 7, 6 components with respect to an electrical angle of 360 ° among components of torque ripple calculated from the waveform of the torque output of fig. 6 are shown. In fig. 7, the magnitude of the torque ripple of comparative example 1 is set to a reference value "100", and the magnitude of the torque ripple of comparative example 2 and embodiment 1 is normalized by the set reference value of comparative example 1.

As is apparent from fig. 5, the torque output of the rotary electric machine 1 according to embodiment 1 is larger than the torque output of the rotary electric machine 300 according to comparative example 2. This is because, since the low magnetic permeability portion 82 is not provided in the central tooth 8 of each tooth group 81, an increase in magnetic resistance in the central tooth 8 can be suppressed, and a decrease in the effective magnetic flux passing through each tooth 8 can be suppressed. As is apparent from fig. 6 and 7, the torque ripple of the rotating electric machine 1 according to embodiment 1 is smaller than the torque ripple of the rotating electric machine 200 according to comparative example 1. This is considered to be an effect of providing the low magnetic permeability portions 82 to the outer 2 teeth 8 in each tooth group 81. As can be seen from fig. 7, the magnitude of the torque ripple in the rotating electric machine 1 according to embodiment 1 is the same as the magnitude of the torque ripple in the rotating electric machine 300 according to comparative example 2. Therefore, it can be confirmed that the rotating electric machine 1 according to embodiment 1 can reduce torque ripple and suppress a decrease in torque output.

In the rotating electric machine 1 according to embodiment 1, in each of the tooth groups 81, the low-magnetic-permeability portions 82 are provided at the distal end portions 83 of the outer 2 teeth 8, avoiding the central tooth 8. Therefore, it is possible to reduce torque ripple and suppress a reduction in torque output.

In each tooth group 81, the low magnetic permeability portions 82 of the 2 teeth 8 disposed respectively on the outer sides are disposed at positions geometrically symmetrical with respect to the center line CL of the central tooth 8 in a cross section perpendicular to the principal axis. Therefore, the waveform of the torque output of the rotating electrical machine 1 can be made the same regardless of which of the clockwise direction and the counterclockwise direction the rotation direction of the rotor 2 is. Therefore, it is possible to prevent a state in which the occurrence of noise and vibration of the rotating electrical machine 1 differs depending on the difference in the rotation direction of the rotor 2.

The low-magnetic-permeability portions 82 are disposed at positions farther from the center line CL of the central tooth 8 in the circumferential direction of the stator 6 than the center lines CL1 and CL2 of the teeth 8 provided with the low-magnetic-permeability portions 82. Therefore, the torque ripple can be reduced, and the reduction in the torque output can be more reliably suppressed.

The low magnetic permeability portion 82 is a space portion formed by a groove 821 provided in the distal end portion 83 of the tooth 8. Therefore, the low-magnetic-permeability portion 82 can be easily provided at the distal end portion 83 of the tooth 8.

The cross-sectional shapes of the low magnetic permeability portions 82 are the same as each other. Therefore, the generation of the 2-order component of the torque ripple with respect to the electrical angle of 360 ° can be suppressed. However, if the generation of the 2-order component of the torque ripple is within the allowable range, the cross-sectional shapes of the low-magnetic-permeability portions 82 may be different from each other.

Further, the same-phase windings 10 are wound around the 3 teeth 8 arranged continuously in the circumferential direction of the stator 6. Therefore, the same-phase winding 10 can be continuously wound around 3 teeth 8. This can shorten the time required for the winding process for winding the winding 10 around each tooth 8, and thus can shorten the manufacturing time of the rotating electric machine 1.

In embodiment 1, the low-magnetic-permeability portions 82 provided on the teeth 8 having the center lines CL1 and CL2 are disposed at positions farther from the center line CL of the central tooth 8 in the circumferential direction of the stator 6 than the center lines CL1 and CL2 of the tooth 8. However, the low-magnetic-permeability portions 82 provided on the teeth 8 having the center line CL1 may be disposed at the same position as the center line CL1 or at a position closer to the center line CL than the center line CL 1. The low-magnetic-permeability portions 82 provided on the teeth 8 having the center line CL2 may be disposed at the same position as the center line CL2 or at a position closer to the center line CL than the center line CL 2. That is, τ may satisfy τ 0 or τ < τ 0. In this way, it is possible to reduce the torque ripple of the rotating electric machine 1 and also to suppress the reduction of the torque output of the rotating electric machine 1.

In embodiment 1, the low magnetic permeability portion 82 formed by the groove 821 has a rectangular cross-sectional shape. However, the cross-sectional shape of the low magnetic permeability portion 82 is not limited to a rectangular shape. For example, as shown in fig. 8, the cross-sectional shape of low magnetic permeability portion 82 formed by groove 821 may be semicircular. As shown in fig. 9, the low magnetic permeability portion 82 formed by the groove 821 may have a triangular cross-sectional shape.

Embodiment mode 2

Fig. 10 is a sectional view showing a rotary electric machine 1 according to embodiment 2. In embodiment 2, among the 3 teeth 8 constituting the tooth group 81, the low magnetic permeability portion 82 is provided at the distal end portion 83 of the other outer tooth 8 while avoiding the center and one outer tooth 8. That is, in each of the tooth groups 81, among the 3 teeth 8, the low-magnetic-permeability portions 82 are not provided in the central and one outer teeth 8, respectively, and the low-magnetic-permeability portions 82 are provided only in the tip end portions 83 of the other outer teeth 8. The low-magnetic-permeability portion 82 is a space portion formed by the groove 821 as in embodiment 1. The other structure of embodiment 2 is the same as embodiment 1.

In fig. 10, the rotational direction of the rotor 2 is counterclockwise when the rotating electrical machine 1 rotates in the forward direction, and the rotational direction of the rotor 2 is clockwise when the rotating electrical machine 1 rotates in the reverse direction. Therefore, in each of the tooth groups 81, the low magnetic permeability portion 82 is provided in the tooth 8 on the rear side in the rotation direction of the rotor 2 when the rotating electrical machine 1 rotates in the normal direction, out of the 3 teeth 8.

Fig. 11 is a graph showing the magnitude of torque output of the rotating electric machine of comparative example 1 shown in fig. 3, the rotating electric machine in the normal rotation of embodiment 2, and the rotating electric machine in the reverse rotation of embodiment 2. Fig. 11 shows magnitudes of torque outputs of the respective rotating electric machines in the case where the rotors 2 are rotated at the same rotation speed. In fig. 11, the magnitude of the torque output of comparative example 1 is set to a reference value "100", and the magnitudes of the torque outputs at the normal rotation and the reverse rotation of embodiment 2 are normalized by the set reference value of comparative example 1.

Fig. 12 is a graph showing the waveforms of the torque outputs of the rotating electric machine of comparative example 1, the rotating electric machine in the normal rotation of embodiment 2, and the rotating electric machine in the reverse rotation of embodiment 2. Fig. 12 shows waveforms of torque output of the rotating electrical machine when the plurality of windings 10 are excited by the same current magnitude at the time of normal rotation in comparative example 1 and embodiment 2 and at the time of reverse rotation in embodiment 2. In fig. 12, the waveform of the torque output in comparative example 1 is shown by a solid line, the waveform of the torque output in the normal rotation of embodiment 2 is shown by a broken line, and the waveform of the torque output in the reverse rotation of embodiment 2 is shown by a one-dot chain line. The torque ripple is calculated by the difference between the maximum value and the minimum value of the waveform of the torque output.

Fig. 13 is a graph showing the magnitude of torque ripple of the rotary electric machine according to comparative example 1, the rotary electric machine according to embodiment 2 in the normal rotation, and the rotary electric machine according to embodiment 2 in the reverse rotation. In fig. 13, 6-th order components with respect to an electrical angle of 360 ° among the components of the torque ripple calculated from the waveform of the torque output of fig. 12 are shown. In fig. 13, the magnitude of the torque ripple of comparative example 1 is set to a reference value "100", and the magnitudes of the torque ripple in the normal rotation and the reverse rotation of embodiment 2 are normalized by the set reference value of comparative example 1.

As is apparent from fig. 11, the magnitude of the torque output of the rotating electric machine 1 according to embodiment 2 is the same for both the normal rotation and the reverse rotation. The magnitude of the torque output of the rotating electrical machine 1 according to embodiment 2 is smaller than the magnitude of the torque output of the rotating electrical machine 200 according to comparative example 1. However, as is clear from a comparison between fig. 11 and 5, the magnitude of the torque output of the rotating electric machine 1 according to embodiment 2 is larger than the magnitude of the torque output of the rotating electric machine 300 according to comparative example 2 shown in fig. 4. This is because, by providing the low-magnetic-permeability portion 82 only in 1 of the 3 teeth 8 of each tooth group 81, the reduction of the effective magnetic flux passing through each tooth 8 can be suppressed as compared with the reduction of the effective magnetic flux in the rotating electrical machine 300 of comparative example 2.

As is apparent from fig. 12 and 13, the torque ripple in the normal rotation and the reverse rotation of the rotating electric machine 1 according to embodiment 2 is smaller than the torque ripple of the rotating electric machine 200 according to comparative example 1. In particular, the magnitude of the torque ripple at the time of normal rotation in embodiment 2 is significantly smaller than that in comparative example 1. On the other hand, when fig. 13 and 7 are viewed, the magnitude of the torque ripple in the reverse rotation of embodiment 2 is larger than that of comparative example 2. Therefore, by providing the low-magnetic-permeability portion 82 only on the tooth 8 located on the rear side in the rotation direction of the rotor 2 among the 3 teeth 8 constituting the tooth group 81, it is possible to effectively reduce torque ripple and suppress a reduction in torque output. Therefore, in the case where the rotating direction of the rotating electric machine 1 is limited to a predetermined direction, it is effective to provide the low-magnetic-permeability portions 82 on the teeth 8 on the rear side in the rotating direction of the rotor 2.

As described above, in the rotating electric machine 1 according to embodiment 2, the low-magnetic-permeability portions 82 are provided at the distal end portions 83 of the 3 teeth 8 constituting each tooth group 81, while avoiding the center and one outer tooth 8, respectively, and at the other outer tooth 8. Therefore, by limiting the rotation direction of the rotor 2 to a predetermined direction, it is possible to reduce torque ripple and suppress a reduction in torque output. That is, by limiting the rotation direction of the rotor 2 to a predetermined direction, the low-magnetic-permeability portion 82 can be provided only on the tooth 8 located on the rear side in the rotation direction of the rotor 2 among the 3 teeth 8 constituting the tooth group 81. Thus, the low-magnetic-permeability portion 82 can be provided in the tooth 8, which effectively reduces torque ripple in the rotation direction of the rotor 2, among the 3 teeth 8 constituting the tooth group 81. In addition, the reduction of the effective magnetic flux contributing to the torque output can be further suppressed. Therefore, it is possible to effectively suppress a decrease in torque output while achieving a decrease in torque ripple.

The low-magnetic-permeability portion 82 may be disposed at the same position as the center line of the tooth 8 on which the low-magnetic-permeability portion 82 is provided, or may be disposed at a position closer to the center line of the tooth 8 at the center than the center line of the tooth 8. In this way, it is possible to reduce the torque ripple of the rotating electric machine 1 and also to suppress the reduction of the torque output of the rotating electric machine 1.

Embodiment 3

Fig. 14 is a sectional view showing a rotary electric machine 1 according to embodiment 3. In each tooth group 81, the distal end portion 83 of each of the 3 teeth 8 out of the central teeth 8 and the 2 teeth 8 on the outer side is provided with a through hole 824 in the direction along the principal axis. In each tooth group 81, the space formed by the through hole 824 is the low magnetic permeability portion 82. The low-magnetic-permeability portion 82 is not provided in the center tooth 8.

The cross-sectional shape of the through-hole 824 is circular. The through hole 824 is located at the same position in the circumferential direction of the stator 6 as the position of the groove 821 in embodiment 1. Therefore, the low-magnetic-permeability portions 82 are arranged at positions farther from the center line CL of the central tooth 8 in the circumferential direction of the stator 6 than the center lines CL1 and CL2 of the teeth 8 provided with the low-magnetic-permeability portions 82. In each tooth group 81, low magnetic permeability portions 82 of 2 teeth 8 provided on the outer side are provided at positions geometrically symmetrical with respect to center line CL of central tooth 8. The other structure of embodiment 4 is the same as embodiment 1.

By providing the through hole 824 at the distal end portion 83 of the tooth 8 in this manner, the space formed by the through hole 824 can be provided as the low-magnetic-permeability portion 82 at the distal end portion 83 of the tooth 8. Therefore, the low-magnetic-permeability portion 82 can be easily provided at the distal end portion 83 of the tooth 8.

In embodiment 3, the low-magnetic-permeability portion 82 formed by the through-hole 824 has a circular cross-sectional shape. However, the cross-sectional shape of the low-magnetic-permeability portion 82 formed by the through-hole 824 is not limited thereto. The low magnetic permeability portion 82 formed by the through hole 824 may have a rectangular or triangular cross-sectional shape.

Embodiment 4

Fig. 15 is a sectional view showing a rotary electric machine 1 according to embodiment 4. In each tooth group 81, among 3 teeth 8, a space portion formed by the groove 821 similar to that of embodiment 1 is provided at the tip portion 83 of each of the 2 teeth 8 outside of the central tooth 8. The space portion formed by the groove 821 is filled with the filler 825 as the low-magnetic-permeability portion 82. That is, low magnetic permeability portion 82 is filler 825 filled in the space portion formed by groove 821. As the filler 825, a resin or the like which is a non-magnetic body is used. The low magnetic permeability portion 82 is not provided in the center tooth 8. The other structure of embodiment 4 is the same as embodiment 1.

In the rotating electric machine 1 according to embodiment 4, the filler 825 is filled in the space portion provided at the distal end portion 83 of the tooth 8 as the low-magnetic-permeability portion 82. Therefore, the space formed by the grooves 821 can be filled with the filler 825, and the filler 825 can be connected in the direction along the main axis. This can improve the rigidity of the teeth 8. Therefore, the resonance frequency of the rotating electric machine can be increased, and the generation of mechanical noise and vibration can be suppressed.

In addition, the filling material 825 is not limited to resin. For example, a metal having a magnetic permeability lower than that of the stator core 7 may also be used as the filler material 825.

In embodiment 4, the space portion provided at the tip portion 83 of the tooth 8 in embodiment 1 is filled with the filler 825. However, the space provided in the distal end portion 83 of the tooth 8 in

embodiments

2 and 3 may be filled with the filler 825.

Embodiment 5

Fig. 16 is a sectional view showing a rotary electric machine according to embodiment 5. In each tooth group 81, of the 3 teeth 8, each distal end portion 83 of the outer 2 teeth 8 is provided with a caulking portion (japanese: かしめ portion) 826 as the low-magnetic-permeability portion 82, avoiding the central tooth 8. The caulking section 826 is a portion for joining the plurality of thin plates stacked in the stator core 7 to each other. The caulking portions 826 provided to the tip portions 83 of the teeth 8 are arranged parallel to the principal axis.

The stator core 7 is manufactured by joining a plurality of laminated raw material plates to each other. The plurality of raw material plates are locally deformed by machining, thereby being joined to each other. The deformed portion of the raw material plate by the machining is formed as a caulking portion 826 for joining the plurality of raw material plates to each other in the stator core 7. On the other hand, the portion of the raw material plate other than the caulking portion 826 becomes a portion of the stator core 7 as a thin plate. The caulking section 826 is magnetically inferior to the stator core 7 due to deformation of the raw material plate by machining. Therefore, the magnetic permeability of rivet 826 is lower than that of stator core 7.

Rivet 826 is circular in shape. The position of the caulking section 826 is the same as the position of the through hole 824 in embodiment 2. The other structure in embodiment 5 is the same as embodiment 1.

In the rotating electric machine 1 according to embodiment 5, the caulking portion 826 provided at the distal end portion 83 of the tooth 8 serves as the low-magnetic-permeability portion 82. Therefore, the plurality of raw material plates can be joined to each other only by forming the caulking portions by machining the plurality of stacked raw material plates, and the low magnetic permeability portion 82 can be provided at the distal end portion 83 of the tooth 8. That is, the formation of the low-magnetic-permeability portion 82 and the joining of the plurality of raw material plates can be performed by 1 step. This can simplify the manufacturing process of the stator core 7, and can facilitate the manufacturing of the rotating electric machine. Further, since no space portion is formed in the distal end portion 83 of the tooth 8, an increase in noise and vibration of the rotating electric machine 1 can also be suppressed.

Embodiment 6

Fig. 17 is an exploded perspective view showing a stator core 7 of a rotating electric machine according to embodiment 6. The stator core 7 has at least 1 st core structural portion 70 and at least 1 nd 2 nd core structural portion 71 as a plurality of core structural portions.

The 1 st core structural portion 70 is a core structural portion in which the low-magnetic-permeability portions 82 are not provided at the distal end portions 83 of all the teeth 8. The 2 nd core structure portion 71 is a core structure portion in which the low magnetic permeability portion 82 is provided at the distal end portion 83 of each of the outer 2 teeth 8, avoiding the central tooth 8, among the 3 teeth 8 of each tooth group 81.

The structure of the 2 nd core structure portion 71 is the structure of the stator core 7 of embodiment 1. Therefore, in the 2 nd core structure portion 71, the space portion formed by the groove 821 is the low magnetic permeability portion 82. The low-magnetic-permeability portion 82 is provided over the entire range of the 2 nd core structure portion 71 in the direction along the principal axis. In addition, low permeability 82 is disposed parallel to the primary axis.

In the stator core 7, the 1 st core structural part 70 and the 2 nd core structural part 71 are alternately overlapped in the direction along the principal axis. In this example, the stator core 7 includes 21 st core

structural parts

70 and 12 nd core structural part 71 as 3 core structural parts. One 1 st core structural portion 70, the 2 nd core structural portion 71, and the other 1 st core structural portion 70 are sequentially overlapped in a direction along the principal axis. Further, the dimensions of the 1 st core structural part 70 and the 2 nd core structural part 71 in the direction along the principal axis are the same as each other.

In the stator core 7, in the direction along the principal axis, the low-magnetic-permeability portion 82 is not present in the range where the 1 st core structural portion 70 is arranged, and the low-magnetic-permeability portion 82 is present in the range where the 2 nd core structural portion 71 is arranged. Therefore, in the tooth 8 provided with the low-magnetic-permeability portion 82, the low-magnetic-permeability portion 82 exists locally in the direction along the main axis. The other structures in embodiment 6 are the same as those in embodiment 1.

In the rotating electrical machine 1 according to embodiment 6, the low-permeability portion 82 is locally present in the direction along the main axis. Therefore, as compared with the case where the low-magnetic-permeability portion 82 exists over the entire range of the stator core 7 in the direction along the principal axis, a decrease in the effective magnetic flux amount contributing to torque output can be suppressed. This can more reliably suppress a decrease in torque output.

In embodiment 6, the stator core 7 includes 21 st core

structural parts

70 and 12 nd core structural part 71. However, as shown in fig. 18, the stator core 7 may include 1 st core

structural part

70 and 2 nd core structural parts 71. In this case, the 2 nd core structural portion 71, the 1 st core structural portion 70, and the 2 nd core structural portion 71 are sequentially overlapped in the direction along the principal axis. In this way, the low-magnetic-permeability portion 82 can also be locally present in the direction along the main axis, and a decrease in torque output can be more reliably suppressed.

In embodiment 6, the number of core structural parts included in the stator core 7 is 3. However, the number of core structure portions included in the stator core 7 may be 2 or 4 or more. In this case, in the stator core 7, the 1 st core structural part 70 and the 2 nd core structural part 71 are alternately overlapped in the direction along the principal axis.

Embodiment 7

Fig. 19 is a vertical sectional view showing an elevator hoisting machine according to embodiment 7. The hoisting machine 100 of an elevator includes a rotating electric machine 1, a drive sheave 101, a housing 102, a frame 103, a brake device 104, and a main shaft 105.

The rotating electric machine 1 is an electric motor that generates a driving force for rotating the drive sheave 101. The rotating electric machine 1 has a rotor 2 and a stator 6. The rotor 2 and the stator 6 have a common axis as a main axis. A main shaft 105 and a cylindrical housing 102 are fixed to the frame 103. The rotor 2, the stator 6, and the housing 102 are disposed coaxially with the main shaft 105.

The drive sheave 101 is rotatably supported by the main shaft 105 via a bearing 108. Thereby, the drive sheave 101 is disposed coaxially with the main shaft 105. A rotor 2 is fixed to the drive sheave 101.

The rotor 2 has a cylindrical rotor core 4 and a plurality of magnetic poles 5, and the plurality of magnetic poles 5 are provided on the outer peripheral surface of the rotor core 4. The cylindrical rotor core 4 is formed integrally with the drive sheave 101. In this example, the material constituting the rotor core 4 and the drive sheave 101 is cast iron. The stator 6 is fixed to the inner circumferential surface of the housing 102. The other structure of the rotating electrical machine 1 is the same as that of the rotating electrical machine 1 according to embodiment 1.

When three-phase ac power is supplied to the plurality of windings 10, the drive sheave 101 and the rotor 2 rotate about the main axis with respect to the main shaft 105 and the stator 6. When the drive sheave 101 and the rotor 2 rotate, the housing 102 receives a reaction force generated by the rotation of the drive sheave 101 and the rotor 2.

The drive sheave 101 is disposed at a position out of the range of the stator 6 in the direction along the main axis. A plurality of main rope grooves 107 are provided along the circumferential direction of the drive sheave 101 on the outer circumferential surface of the drive sheave 101. A plurality of main ropes suspending a car and a counterweight, not shown, are wound around the drive sheave 101 along the main rope grooves 107. By the rotation of the drive sheave 101, the car and the counterweight move in the vertical direction in the hoistway.

Brake device 104 is provided inside cylindrical rotor core 4. The braking device 104 applies a braking force to the drive sheave 101 and the rotor 2. The brake device 104 includes brake shoes, not shown, which are displaceable in the radial direction of the rotor 2 with respect to the rotor core 4. The brake device 104 applies a braking force to the drive sheave 101 and the rotor 2 by bringing brake shoes into contact with the inner circumferential surface of the rotor core 4. The brake device 104 releases the braking force applied to the drive sheave 101 and the rotor 2 by separating the brake shoe from the rotor core 4.

The hoisting machine 100 for an elevator according to embodiment 7 includes a rotating electrical machine 1 having the same configuration as that of embodiment 1 as a motor. Therefore, as in embodiment 1, it is possible to reduce the torque ripple of the hoisting machine 100 of the elevator and to suppress the reduction in the torque output of the hoisting machine 100 of the elevator. This reduces vibration of the car caused by torque pulsation of the rotating electric machine 1, and reduces sway of the car during operation of the elevator.

In embodiment 7, the rotor 2 rotates integrally with the drive sheave 101. However, a hoisting machine having a geared motor in which a reducer including a gear and rotating electrical machine 1 as a motor are integrated may be used as hoisting machine 100 of the elevator. In this case, the drive sheave 101 is rotated by the rotational force output from the reduction gear of the geared motor.

Instead of the rotating electric machine 1 according to embodiment 1, the rotating electric machine 1 according to embodiments 2 to 6 may be used as the motor of the hoisting machine 100 of the elevator.

In each of the above embodiments, a rotating electrical machine in which the number of magnetic poles 5 of the rotor 2 is 10 poles and the number of slots of the stator core 7 is 9, that is, a 10-pole 9-slot rotating electrical machine is used as the rotating electrical machine 1. However, a rotating electrical machine in which the number of magnetic poles 5 of the rotor 2 is 8 poles and the number of slots of the stator core 7 is 9, that is, a rotating electrical machine in which 8 poles and 9 slots are used as the rotating electrical machine 1 may be used.

In each of the above embodiments, a combination of 10 poles and 9 slots may be defined as 1 unit a, and a combination of 10n poles and 9n slots, which is n times the number of the units a, may be defined as a combination of the number of the magnetic poles 5 of the rotor 2 and the number of the slots of the stator core 7. In this case, the number of windings 10 is 9 n. Further, a combination of 8 poles and 9 slots may be defined as 1 unit B, and a combination of 8n poles and 9n slots, which is an integer n times the 1 unit B, may be defined as a combination of the number of magnetic poles 5 of the rotor 2 and the number of slots of the stator core 7. In this case, the number of windings 10 is also 9 n.

In each of the above embodiments, the number of low magnetic permeability portions 82 provided to the tip portion 83 of the tooth 8 is set so that 1 low magnetic permeability portion 82 is provided for 1 tooth 8. However, 2 or more low-magnetic-permeability portions 82 may be provided at the distal end portion 83 of the tooth 8 for 1 tooth 8.

In each of the above embodiments, the back yoke 9 includes a plurality of back yoke members 91 arranged in an annular shape. However, the back yoke 9 may be an annular body integrally molded without being divided into a plurality of back yoke members.

In each of the above embodiments, a Surface Magnet type (SPM) rotating electrical machine in which a plurality of magnetic poles 5 are arranged on the outer peripheral Surface of the rotor core 4 is used as the rotating electrical machine 1. However, an Interior Magnet type (IPM) rotating electrical machine in which a plurality of magnetic poles 5 are embedded in the rotor core 4, or a commutating pole type rotating electrical machine in which Permanent magnets and magnetic salient poles are alternately arranged in the circumferential direction may be used as the rotating electrical machine 1.

In each of the above embodiments, an internal rotor structure in which the rotor 2 is disposed inside the annular stator 6 is used as the rotating electric machine 1. However, a rotating electrical machine having an outer rotor structure in which the annular rotor 2 is disposed outside the stator 6 may be used as the rotating electrical machine 1.

Description of the reference symbols

1: a rotating electric machine; 2: a rotor; 4: a rotor core; 5: a magnetic pole; 6: a stator; 7: a stator core; 8: teeth; 9: a back yoke; 10: a winding; 81: a set of teeth; 82: a low-magnetic-permeability portion; 821: a groove; 824: a through hole; 825: a filler material; 826: riveting parts; 100: a hoist for an elevator.

Claims

1. A rotating electrical machine is provided with:

a rotor that rotates about an axis; and

a stator facing the rotor with a gap therebetween in a radial direction of the rotor,

the rotor has a rotor core and a plurality of magnetic poles provided to the rotor core and arranged in a circumferential direction of the rotor,

the stator has a stator core and a plurality of windings provided to the stator core,

the stator core has a back yoke and a plurality of teeth protruding from the back yoke toward the rotor,

the plurality of teeth are arranged at intervals in a circumferential direction of the stator,

each of the teeth has a tip portion that is opposed to the rotor,

the winding is wound around the teeth by concentrated winding,

3 of the teeth arranged continuously in the circumferential direction of the stator constitute a tooth group,

the windings of the same phase are wound around 3 teeth constituting 1 of the tooth groups,

in the tooth group, among the 3 teeth, the distal end portions of the 2 teeth on the outer side avoiding the central tooth are provided with low-magnetic-permeability portions,

the low-magnetic-permeability portion has a lower magnetic permeability than the stator core.

2. The rotating electric machine according to claim 1,

in the tooth group, the low-magnetic-permeability portions of the 2 teeth disposed respectively on the outer side are disposed at positions geometrically symmetrical with respect to a center line of the central tooth in a cross section perpendicular to the axis.

3. A rotating electrical machine is provided with:

a rotor that rotates about an axis; and

each of the teeth has a tip portion that is opposed to the rotor,

the winding is wound around the teeth by concentrated winding,

the windings of the same phase are wound on 3 teeth constituting 1 tooth group,

in the tooth group, among the 3 teeth, the distal end portions of the teeth on the other outer side are provided with low-magnetic-permeability portions while avoiding the center and the teeth on the one outer side,

4. The rotary electric machine according to any one of claims 1 to 3,

the low-magnetic-permeability portion is disposed at a position farther from a center line of the tooth at the center in the circumferential direction of the stator than the center line of the tooth provided with the low-magnetic-permeability portion.

5. The rotary electric machine according to any one of claims 1 to 4,

the low-magnetic-permeability portion is a space portion formed by a groove provided at the distal end portion of the tooth.

6. The rotating electric machine according to any one of claims 1 to 4,

the low-magnetic-permeability portion is a space formed by a through hole provided in the distal end portion of the tooth.

7. The rotating electric machine according to any one of claims 1 to 4,

the low-magnetic-permeability portion is a filler material filled in a space portion provided at the distal end portion of the tooth.

8. The rotating electric machine according to any one of claims 1 to 4,

the low-magnetic-permeability portion is a caulking portion provided at the distal end portion of the tooth.

9. The rotary electric machine according to any one of claims 1 to 8,

in the tooth provided with the low-magnetic-permeability portion, the low-magnetic-permeability portion is locally present in a direction along the axis.

10. A hoisting machine for an elevator, comprising the rotating electrical machine according to any one of claims 1 to 9.