CN217720858U

CN217720858U - Magnetic steel, motor outer rotor and motor

Info

Publication number: CN217720858U
Application number: CN202221628618.9U
Authority: CN
Inventors: 唐伟; 李东虎; 米红湖
Original assignee: Chongqing Dile Jinchi General Machinery Co ltd
Current assignee: Chongqing Dile Jinchi General Machinery Co ltd
Priority date: 2022-06-28
Filing date: 2022-06-28
Publication date: 2022-11-01
Anticipated expiration: 2032-06-28

Abstract

The utility model discloses a magnet steel, motor external rotor and motor, wherein, the magnet steel inner wall is provided with first group auxiliary tank and second group auxiliary tank along axial direction, and wherein the second group auxiliary tank is in first group auxiliary tank inboard, and first group auxiliary tank and second group auxiliary tank all include the auxiliary tank of two symmetries each. The utility model can pertinently inhibit certain harmonic magnetic field components with larger air gap amplitude, and simultaneously can not reduce the fundamental magnetic field in a larger range; and the torque pulsation, noise and vibration of the outer rotor surface-mounted permanent magnet motor can be greatly reduced.

Description

Magnetic steel, motor outer rotor and motor

Technical Field

The utility model relates to the technical field of electric machine, especially relate to a magnet steel, motor external rotor and motor.

Background

The outer rotor surface-mounted permanent magnet motor has the advantages of simple structure, high power density, wide operating speed range and the like, and is widely applied to various different industrial fields. In order to increase the magnetic field intensity of the outer rotor surface-mounted permanent magnet motor, the pole arc coefficient of the magnetic steel can only be increased under the condition that the number of the magnetic steel is fixed with the thickness of the magnetic steel. When the maximum value of the pole arc coefficient of the magnetic steel is 1, the air gap magnetic field generated by the magnetic steel approaches to square waves, the harmonic component is very large, the harmonic loss of the motor is large, the torque fluctuation is large, and the operation noise is high.

At present, an outer rotor surface-mounted permanent magnet motor rotor with a pole arc coefficient of 1 adopts a quasi-trapezoidal permanent magnet rotor to form an uneven air gap, so that an air gap magnetic field is optimized, and the motor operation noise is reduced. But the harmonic magnetic field is optimized by adopting the method, the fundamental magnetic field is also reduced, and the original purpose of increasing the magnetic field strength of the outer rotor surface-mounted permanent magnet motor to the greatest extent is violated.

Therefore, the technical personnel in the field are dedicated to develop the magnetic steel, the outer rotor of the motor and the motor which do not reduce the simultaneous vibration of the fundamental wave magnetic field and have low operation noise.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned defect of the prior art, the utility model aims to solve the technical problem that a do not reduce fundamental wave magnetic field simultaneous vibration, low magnet steel of running noise, motor external rotor and motor are provided.

In order to achieve the above object, the utility model provides a magnet steel, the magnet steel inner wall is provided with first group auxiliary tank and second group auxiliary tank along axial direction, and wherein the second group auxiliary tank is at first group auxiliary tank inboard, and first group auxiliary tank and second group auxiliary tank all respectively include the auxiliary tank of two symmetries. The utility model discloses set up two auxiliary grooves on magnet steel inner arc surface, such outer rotor surface-mounted permanent-magnet machine can select the great harmonic magnetic field component of specific air gap amplitude; through the mode of arranging 4, totally 2 groups of auxiliary grooves on the inner arc surface of the magnetic steel, specific harmonic magnetic field components with larger air gap amplitude are pertinently inhibited, and meanwhile, the fundamental magnetic field is not reduced in a larger range, so that the defect that the harmonic magnetic field is optimized and the fundamental magnetic field of the fundamental air gap is weakened by the outer rotor surface-mounted permanent magnet motor quasi-trapezoidal magnetic steel with the pole arc coefficient of 1 at present is solved.

Preferably, the auxiliary slots in the first set of auxiliary slots and the second set of auxiliary slots are symmetrically distributed along the center line of the magnetic pole.

Preferably, the difference of the electrical angle between the first set of auxiliary slots and the position of the center line of the magnetic pole is theta₁The difference of the electrical angle between the second group of auxiliary grooves and the position of the center line of the magnetic pole is theta₂，0°≤θ₂＜θ₁≤90°。

Preferably, the pole arc coefficient of the magnetic steel is 1.

Preferably, the first set of auxiliary slots has an electrical angle difference theta with respect to the center line position of the magnetic pole₁Is 78 degrees, and the position of the second group of auxiliary grooves and the center line of the magnetic pole has an electrical angle difference theta₂Is 11 deg..

Preferably, the first set of auxiliary grooves and the second set of auxiliary grooves have an elliptical profile, and the arc angle is less than or equal to 90 °.

Preferably, the ratio of the minor axis length to the major axis length of the first set of auxiliary grooves is λ₁The ratio of the minor axis length to the major axis length of the second group of auxiliary grooves is λ₂Wherein λ is₁Is 0.5, lambda₂Is 0.25.

Preferably, the ratio λ of the minor axis length to the major axis length of the first set of auxiliary grooves₁0.5, the ratio of the minor axis length to the major axis length of the second set of auxiliary grooves is lambda₂Is 0.25.

The utility model also provides a motor external rotor, include as above the magnet steel, the rotor core inner wall is located to the magnet steel, the whole cubic arc that is of magnet steel.

The utility model also provides a motor, include as above magnet steel or last motor external rotor.

Preferably, the motor comprises 2P pieces of magnetic steel, the number of stator slots of the magnetic steel is Ns, and the number of the pieces of the magnetic steel and the number of the stator slots Ns satisfy the following relationship: ns =2P ± 2.

The beneficial effects of the utility model are that: the utility model can pertinently inhibit certain harmonic magnetic field components with larger air gap amplitude, and simultaneously can not reduce the fundamental magnetic field in a larger range; and the torque pulsation, noise and vibration of the outer rotor surface-mounted permanent magnet motor can be greatly reduced.

Drawings

Fig. 1 is a schematic structural diagram of an outer rotor of a motor according to an embodiment of the present invention.

Fig. 2 is a schematic top view of the magnetic steel according to an embodiment of the present invention.

Fig. 3 is a comparison diagram of the magnetic density of the radial air gap in the front and the back of the motor magnet steel.

Figure 4 is motor magnet steel adopts the utility model discloses radial air gap flux density Fourier analysis contrasts the picture around.

Fig. 5 is a front-rear torque comparison diagram of the motor magnetic steel.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and examples, wherein it is noted that, in the description of the invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular manner, and therefore should not be construed as limiting the present invention. The terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

As shown in fig. 1 and fig. 2, a magnetic steel 1 is made of ferrite, neodymium iron boron, and samarium cobalt. The pole arc coefficient is 1. The inner wall of the magnetic steel 1 is provided with a first group of auxiliary grooves 11 and a second group of auxiliary grooves 12 along the axial direction, wherein the second group of auxiliary grooves 12 are arranged on the inner side of the first group of auxiliary grooves 11, and the first group of auxiliary grooves 11 and the second group of auxiliary grooves 12 respectively comprise two symmetrical auxiliary grooves. Specifically, the auxiliary slots in the first group of auxiliary slots 11 and the second group of auxiliary slots 12 are symmetrically distributed along the center line Y of the magnetic pole.

The difference of the electrical angle between the first group of auxiliary slots 11 and the position of the center line of the magnetic pole is theta₁The difference between the electrical angle of the second set of auxiliary slots 12 and the position of the center line of the magnetic pole is theta₂Specifically, the difference between the electrical angle of the connecting line of the midpoint of the notch of the first group of auxiliary slots 11 and the center point of the motor and the position of the center line of the magnetic pole is theta₁The middle point of the notch of the second group of auxiliary grooves 12 and the motorThe electrical angle difference between the connecting line of the central dots and the central line of the magnetic pole is theta₂，0°≤θ₂＜θ₁Is less than or equal to 90 degrees. In this embodiment, the electrical angle difference θ between the first set of auxiliary slots 11 and the center line of the magnetic pole₁Is 78 degrees, and the position of the second group of auxiliary grooves 12 and the center line of the magnetic pole has an electrical angle difference theta₂Is 11 deg..

The first and second sets of

auxiliary grooves

11, 12 are elliptical arcs in profile, and the arc angle is less than or equal to 90 °. In this embodiment, the arc angle is 90 °, i.e. it is a semi-ellipse, and the ratio of the length of the minor axis to the length of the major axis of the first group of auxiliary grooves 11 is λ₁The ratio of the minor axis length to the major axis length of the second set of auxiliary grooves 12 is λ₂Wherein 0 is not more than λ₁≤3，0≤λ₂3 or less, in this example lambda₁Is 0.5, lambda₂Is 0.25. In this embodiment, the long axis is aligned with the radial direction of the magnetic steel.

The utility model also provides an outer rotor of motor, include as

above magnet steel

1, 2 inner walls of rotor core are located to magnet steel 1, and magnet steel 1 is whole to be cubic arc. Specifically in the use, the motor outer rotor is hollow cylinder (only show partial outer rotor structure in fig. 1), including rotor core 2, magnet steel 1's radian is pasted in rotor core 2 inner wall, according to actual conditions, rotor core 2 is inside can to be established a plurality of magnet steels 1, makes polylith steel 1 all paste in rotor core 2's inside, preferred 2P piece magnet steel, wherein, ns is the stator slot number, and Ns =2P 2, forms the electron outer rotor of a concatenation formula.

An electric machine comprises the magnetic steel 1 or the outer rotor of the electric machine. The magnetic steel stator comprises 2P magnetic steels 1, wherein the number of stator slots of each magnetic steel 1 is Ns, and the number of blocks of the magnetic steel 1 and the number of stator slots Ns meet the following relation: ns =2P ± 2. The utility model provides a motor can have corresponding suppression to fall the great harmonic magnetic field component of specific certain air gap amplitude, can not reduce the fundamental wave magnetic field in the great scope simultaneously, has reduced motor torque pulsation, noise and vibration.

In this embodiment, adopt finite element analysis software Maxwell, test ordinary outer rotor permanent-magnet machine respectively (the magnet steel does not set up the auxiliary tank) and adopt the utility model discloses a permanent-magnet machine to output performance. As shown in fig. 3 and 4, it can be known through analysis that the radial air gap flux density waveform and amplitude of the motor and the motor before slotting are not greatly changed by adopting the present invention. After the air gap magnetic density Fourier analysis of the two parts is compared, the following obvious results can be seen: the radial air gap flux density fundamental wave amplitude of the motor before optimization (the magnetic steel is not slotted) is 0.87T, and the radial air gap flux density fundamental wave amplitude of the motor after optimization (the utility model) is 0.83T; the radial air gap flux density 3th harmonic amplitude of the motor before optimization is 0.28T, and the radial air gap flux density 3th harmonic amplitude of the motor after optimization is 0.16T; the harmonic amplitude of the radial air gap flux density 5th of the motor before optimization is 0.15T, and the harmonic amplitude of the radial air gap flux density 5th of the motor after optimization is 0.02T; the amplitude of the radial air gap flux density 7th harmonic wave of the motor before optimization is 0.1023T, and the amplitude of the radial air gap flux density 7th harmonic wave of the motor after optimization is 0.0422T. It can be seen from the above experiment, the utility model discloses corresponding suppression has fallen the great harmonic magnetic field component of air gap amplitude such as 3th, 5th, 7th, and fundamental component does not have great loss simultaneously.

Meanwhile, after the output performance of the generator is calculated by adopting finite element analysis software Maxwell, as shown in FIG. 5, the fluctuation of the motor torque is obviously reduced, and the average value of the motor torque before optimization is 5.84Nm and the torque ripple is 25.6%; the torque average value of the optimized motor is 5.71Nm, and the torque ripple is 14.01%.

It can be seen from the above-mentioned experiment, the utility model discloses there is the great harmonic magnetic field component of specific certain air gap amplitude that has pertinence to be suppressed, can not reduce the fundamental wave magnetic field in the great scope simultaneously. The torque pulsation, noise and vibration of the surface-mounted permanent magnet motor with the magnetic steel outer rotor are reduced.

The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the teachings of the present invention without undue experimentation. Therefore, the technical solutions that can be obtained by logical analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention by those skilled in the art should be within the scope of protection defined by the claims.

Claims

1. The utility model provides a magnet steel, characterized by: the magnet steel inner wall is provided with first group auxiliary groove (11) and second group auxiliary groove (12) along axial direction, and wherein second group auxiliary groove (12) are inboard in first group auxiliary groove (11), and first group auxiliary groove (11) and second group auxiliary groove (12) all include the auxiliary groove of two symmetries respectively.

2. The magnetic steel of claim 1, wherein: the auxiliary grooves in the first group of auxiliary grooves (11) and the second group of auxiliary grooves (12) are symmetrically distributed along the center line of the magnetic pole.

3. The magnetic steel of claim 1, wherein: the difference of the electrical angle between the first group of auxiliary grooves (11) and the position of the center line of the magnetic pole is theta₁The difference between the electrical angle of the second group of auxiliary grooves (12) and the position of the center line of the magnetic pole is theta₂，0°≤θ₂＜θ₁≤90°。

4. The magnetic steel of claim 1, wherein: the polar arc coefficient of the magnetic steel is 1.

5. The magnetic steel of claim 3, wherein: the first group of auxiliary grooves (11) has an electrical angle difference theta with the position of the center line of the magnetic pole₁At 78 DEG, the second group of auxiliary grooves (12) has an electrical angle difference theta with the position of the magnetic pole center line₂Is 11 deg..

6. The magnetic steel of claim 1, wherein: the profiles of the first group of auxiliary grooves (11) and the second group of auxiliary grooves (12) are elliptic arcs, and the arc angle is smaller than or equal to 90 degrees.

7. The magnetic steel of claim 6, wherein: the ratio of the minor axis length to the major axis length of the first set of auxiliary grooves (11) is λ₁The ratio of the minor axis length to the major axis length of the second set of auxiliary grooves (12) is λ₂Wherein, 0 is not more than lambda₁≤3，0≤λ₂≤3。

8. The magnetic steel of claim 7, wherein: the ratio of the length of the minor axis to the length of the major axis of the first set of auxiliary grooves (11) is lambda₁Is 0.5, the ratio λ of the minor axis length to the major axis length of the second set of auxiliary grooves (12)₂Is 0.25.

9. An outer rotor of a motor is characterized in that: the magnetic steel (1) comprises the magnetic steel (1) according to any one of claims 1 to 8, wherein the magnetic steel (1) is arranged on the inner wall of the rotor core (2), and the magnetic steel (1) is integrally in a block-shaped arc shape.

10. An electric machine, characterized by: comprises magnetic steel (1) according to any one of claims 1 to 8 or an outer rotor of an electric machine according to claim 9.

11. The electric machine of claim 10, further comprising: the magnetic steel stator comprises 2P magnetic steel (1), wherein the number of stator slots of the magnetic steel (1) is Ns, and the number of blocks of the magnetic steel (1) and the number of stator slots Ns meet the following relation: ns =2P ± 2.