阅读说明：本技术 基于外转子铁心偏心结构设计的正弦波转子 (Sine wave rotor designed based on outer rotor iron core eccentric structure ) 是由 韩坤 苏森 王志强 陈胜林 于 2021-06-04 设计创作，主要内容包括：本发明涉及电动机技术领域,具体公开了一种基于外转子铁心偏心结构设计的正弦波转子；包括外转子铁心、永磁体、定子、内转子铁心和转子轴,外转子铁心和内转子铁心分别安装在转子轴的外端和外端,永磁铁沿内转子铁心的径向外侧交替放置,外转子铁心的外廓为圆形、内廓由周向的多个向内凸起的偏心圆弧构成,外转子铁心与永磁体之间构成了环形气隙,定子置于环形气隙内；本发明采用基于偏心圆弧结构特殊设计后的外转子铁心,使得电机的径向气隙厚度边的不均匀,气隙径向厚度变化更为合理,改善了电机气隙磁密波形,减小气隙磁场中谐波含量,使气隙磁场接近正弦波,从而改善了空心杯型电机反电动势波形,降低了转矩脉动,提升了电机性能。(The invention relates to the technical field of motors, and particularly discloses a sine wave rotor designed based on an outer rotor iron core eccentric structure; the permanent magnet motor comprises an outer rotor iron core, permanent magnets, a stator, an inner rotor iron core and a rotor shaft, wherein the outer rotor iron core and the inner rotor iron core are respectively arranged at the outer end and the outer end of the rotor shaft; the invention adopts the outer rotor iron core which is specially designed based on the eccentric circular structure, so that the thickness edge of the radial air gap of the motor is not uniform, the change of the radial thickness of the air gap is more reasonable, the air gap flux density waveform of the motor is improved, the harmonic content in the air gap magnetic field is reduced, the air gap magnetic field is close to a sine wave, the back electromotive force waveform of the hollow cup type motor is improved, the torque pulsation is reduced, and the motor performance is improved.)

1. A sine wave rotor designed based on an eccentric structure of an outer rotor iron core comprises the outer rotor iron core, a permanent magnet, a stator, an inner rotor iron core and a rotor shaft, the radial outer side of the outer rotor iron core is arranged at the outer end of the rotor shaft, the radial inner side of the inner rotor iron core is arranged at the inner end of the rotor shaft, it is characterized in that a plurality of tile-shaped permanent magnets are alternately arranged along the radial outer side of the inner rotor iron core, the magnetizing directions of two adjacent permanent magnets are opposite, the outer contour of the outer rotor iron core is circular, the inner contour of the outer rotor iron core is formed by a plurality of circumferential eccentric arcs protruding inwards, the number of the eccentric arcs is the same as that of the permanent magnets, the positions of the eccentric arcs correspond to the permanent magnets one by one, an annular air gap is formed between the radial inner side of the outer rotor iron core and the permanent magnets, and the stator is arranged in the annular air gap and fixed on the machine shell;

the circular outline of the outer rotor iron core, the inner outline and the outer outline of the permanent magnet and the inner outline and the outer outline of the inner rotor iron core are arranged concentrically, the concentric point is the geometric center of the rotor, two end points of the eccentric arc are positioned on the extension line of the connecting line of the two side edges of the corresponding permanent magnet and the geometric center of the rotor, the circle center of the eccentric arc is positioned on the reverse extension line of the connecting line of the middle point of the corresponding permanent magnet and the geometric center of the rotor, and the circle center of the eccentric arc is positioned on the radial outer side of the outer rotor iron core.

2. The sine wave rotor designed based on the outer rotor core eccentric structure according to claim 1, wherein the distance from the midpoint of the eccentric arc to the geometric center of the rotor isAnd satisfies the relation:whereinIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet.

3. The sine wave rotor designed based on the outer rotor core eccentric structure according to claim 2, wherein the radius of the eccentric arc is such that the relation:

whereinIs the number of pole pairs.

4. The sine wave rotor designed based on the eccentric structure of the outer rotor core as recited in claim 2, further comprising tile-shaped magnetic barriers with the same number as the permanent magnets, wherein the magnetic barriers are disposed between two adjacent permanent magnets, and two end points of the eccentric arc are located on an extension line connecting the center of the tile-shaped edges of the magnetic barriers at two sides of the corresponding permanent magnet and the geometric center of the rotor.

5. The sine wave rotor designed based on the eccentric structure of the outer rotor core as claimed in claim 4, wherein the inner diameter of the tile shape of the magnetic isolation block isAnd satisfies the relation:(ii) a The tile-shaped outer diameter of the magnetic isolation block isAnd satisfies the relation:(ii) a WhereinIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet.

6. The sine wave rotor designed based on the eccentric structure of the outer rotor core as recited in claim 5, wherein the tile-shaped opening angle of the magnetic isolation block isAnd satisfies the relation:the tile-shaped opening angle of the permanent magnetSatisfy the relationWhereinThe number of pole pairs of the motor is shown.

7. The sine wave rotor designed based on the outer rotor core eccentric structure according to claim 6, wherein the radius of the eccentric arc isAnd satisfies the relation:

whereinThe coefficient of the magnetic isolation block satisfies the relation:。

8. according to claim3 or 7, the sine wave rotor designed based on the eccentric structure of the outer rotor core is characterized in that the distance between the center of the eccentric arc and the geometric center of the rotor is an eccentric valueAnd satisfies the relation:。

9. the sine wave rotor designed based on the eccentric structure of the outer rotor core as claimed in claim 8, wherein the radius of the circular contour of the outer rotor core is set to beAnd satisfies the relation:。

10. the sine wave rotor designed based on the eccentric structure of the outer rotor core according to claim 1 or 4, wherein the number of the eccentric arcs on the outer rotor core is as follows, and satisfies the relation:whereinIs the number of pole pairs.

Technical Field

The invention relates to the technical field of motors, and particularly discloses a sine wave rotor designed based on an outer rotor iron core eccentric structure.

Background

The traditional permanent magnet synchronous motor and sine wave motor are mostly applied to high-rotating-speed occasions and need high speed regulation precision, so that the traditional permanent magnet synchronous motor and sine wave motor are mostly driven and controlled by sine wave phase current, and the sine wave phase current needs to interact with sine wave counter electromotive force so as to reduce electromagnetic torque pulsation. In the traditional hollow cup type permanent magnet motor, the harmonic content of 3, 5 and 7 times in the waveform of the back electromotive force is large, so that the motor generates electromagnetic torque pulsation, and the performance and the efficiency of the motor are influenced. The main reason that the waveform of the back electromotive force of the hollow cup type permanent magnet motor has higher harmonic content is that the sine type of the waveform of the air gap magnetic field of the motor is poorer, and more odd harmonics are mixed, so that the air gap magnetic field of the motor is close to a trapezoid, and the harmonic content of the waveform of the back electromotive force is higher. Therefore, the optimization of the motor structure and the reduction of the harmonic content of the air-gap magnetic field waveform are of great importance to enable the air-gap magnetic field waveform to be close to a sine wave.

The invention patent with application number 2010101099694 discloses a stator-free iron core permanent magnet synchronous motor which mainly comprises a rotor shaft, an inner rotor iron core, a magnetic isolation block, a hollow cup stator, a Halbach permanent magnet and an outer rotor iron core, wherein the magnetic isolation block is embedded in the inner rotor iron core and forms an inner rotor component part together with the inner rotor iron core, the outer rotor iron core and the permanent magnet are connected to the rotor shaft, the Halbach permanent magnet is attached to the outer rotor iron core, and the hollow cup stator is fixed on a machine shell. The permanent magnetic circuit forms a closed loop through the inner rotor iron core, the magnetic air gap, the Halbach permanent magnet and the outer rotor iron core. The hollow cup stator structure can be used in the design of a permanent magnet synchronous motor, so that the inner rotor core and the outer rotor core synchronously rotate along with the permanent magnet, loss can not be generated in the cores, meanwhile, the hollow cup stator enables the stator to be a tooth-slot-free structure, the cogging torque and tooth harmonic can be eliminated, but the radial air gap magnetic resistance is consistent due to uniform radial thickness of an air gap, the distribution of an air gap magnetic field is influenced, the air gap magnetic field harmonic content is large, and the sine performance is poor; in addition, because the permanent magnets are in direct contact with each other, interpolar magnetic flux leakage is generated, and the performance of the motor is influenced. Therefore, aiming at the defects of large air gap magnetic field harmonic content and poor sine performance in the existing permanent magnet synchronous motor and sine wave motor, the technical problem to be solved is to design a rotor with optimized structure, wherein the rotor can reduce the air gap magnetic field waveform harmonic content and make the air gap magnetic field waveform approach to the sine wave.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the sine wave rotor overcomes the defects of the prior art, can be used for an outer rotor core eccentric structure in a permanent magnet synchronous motor and a sine wave motor, and solves the problem that the difference between the air gap magnetic field waveform and the sine wave is large.

The invention is realized by the following technical scheme:

a sine wave rotor designed based on an eccentric structure of an outer rotor iron core comprises the outer rotor iron core, permanent magnets, a stator, an inner rotor iron core and a rotor shaft, wherein the radial outer side of the outer rotor iron core is arranged at the outer end of the rotor shaft, the radial inner side of the inner rotor iron core is arranged at the inner end of the rotor shaft, a plurality of tile-shaped permanent magnets are alternately arranged along the radial outer side of the inner rotor iron core, the magnetizing directions of two adjacent permanent magnets are opposite, the outer contour of the outer rotor iron core is circular, the inner contour of the outer rotor iron core is formed by a plurality of circumferential inwards-convex eccentric arcs, the number of the eccentric arcs is the same as that of the permanent magnets, the positions of the eccentric arcs correspond to the permanent magnets one by one, an annular air gap is formed between the radial inner side of the outer rotor iron core and the permanent magnets, and the stator is arranged in the annular air gap and fixed on a machine shell;

the circular outline of the outer rotor iron core, the inner outline and the outer outline of the permanent magnet and the inner outline and the outer outline of the inner rotor iron core are arranged concentrically, the concentric point is the geometric center of the rotor, two end points of the eccentric arc are positioned on the extension line of the connecting line of the two side edges of the corresponding permanent magnet and the geometric center of the rotor, the circle center of the eccentric arc is positioned on the reverse extension line of the connecting line of the middle point of the corresponding permanent magnet and the geometric center of the rotor, and the circle center of the eccentric arc is positioned on the radial outer side of the outer rotor iron core.

As a further provision of the above solution, the distance from the midpoint of the eccentric arc to the geometric center of the rotor isAnd satisfies the relation:whereinIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet.

As a further arrangement of the above solution, the radius of the eccentric arc isAnd satisfies the relation:

whereinThe number of pole pairs of the motor is shown.

The magnetic isolation device is characterized by further comprising tile-shaped magnetic isolation blocks which are equal to the permanent magnets in number, the magnetic isolation blocks are arranged between every two adjacent permanent magnets, and two end points of the eccentric arc are located on an extension line of a connecting line between the middle point of tile-shaped edges of the magnetic isolation blocks on the two sides of the corresponding permanent magnets and the geometric center of the rotor.

As a further arrangement of the above scheme, the tile-shaped inner diameter of the magnetic isolation block isAnd satisfies the relation:(ii) a The tile-shaped outer diameter of the magnetic isolation block isAnd satisfies the relation:(ii) a WhereinIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet.

As a further arrangement of the above scheme, the tile-shaped opening angle of the magnetic isolation block isAnd satisfies the relation:the tile-shaped opening angle of the permanent magnetSatisfy the relationWhereinThe number of pole pairs of the motor is shown.

As a further arrangement of the above solution, the radius of the eccentric arc isAnd satisfies the relation:

whereinThe coefficient of the magnetic isolation block satisfies the relation:。

as a further arrangement of the above solution, the distance between the center of the eccentric arc and the geometric center of the rotor is an eccentricity valueAnd satisfies the relation:。

as a further configuration of the above aspect, the radius of the circular outer contour of the outer rotor core isAnd satisfies the relation:。

as a further configuration of the above aspect, the number of the eccentric arcs on the outer rotor core isAnd satisfies the relation:whereinThe number of pole pairs of the motor is shown.

Has the advantages that:

compared with the prior art, the invention has the advantages that: the invention adopts the outer rotor iron core which is specially designed based on the eccentric circular structure, so that the thickness edge of the radial air gap of the motor is not uniform, the change of the radial thickness of the air gap is more reasonable, the air gap flux density waveform of the motor is improved, the harmonic content in the air gap magnetic field is reduced, the air gap magnetic field is close to a sine wave, the back electromotive force waveform of the hollow cup type motor is improved, the torque pulsation is reduced, and the motor performance is improved. Meanwhile, compared with the traditional hollow cup permanent magnet motor, the permanent magnet is attached to the inner rotor iron core, so that the radius is reduced, and the permanent magnet material is saved; and the permanent magnets are separated by the magnetic separation blocks, so that magnetic loops generated on the sides of the permanent magnets are reduced, interpolar magnetic leakage is reduced, and the motor performance is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural view of example 1 of the present invention;

FIG. 2 is a partial schematic structural view of embodiment 1 of the present invention;

FIG. 3 is a schematic diagram showing the comparison between the air gap field of the coreless permanent magnet synchronous motor of embodiment 1 of the present invention and that of the conventional coreless motor;

FIG. 4 is a schematic structural view of example 2 of the present invention;

FIG. 5 is a partial structural view of embodiment 2 of the present invention;

fig. 6 is a schematic diagram showing the comparison of the air gap field of the coreless sine wave motor of embodiment 2 of the present invention with that of the conventional coreless motor.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "mounted," "disposed," "provided," "connected," "sleeved," "laid," and the like are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will now be described in detail with reference to the accompanying figures 1-6, in conjunction with an illustrative embodiment.

Example 1

Embodiment 1 discloses a sine wave rotor designed based on an outer rotor core eccentric structure, which is used in a hollow cup type permanent magnet motor. Referring to fig. 1 and 2, which include an outer rotor core 1, a permanent magnet 2, a coreless stator 3, an inner rotor core 4, and a rotor shaft 5, the outer rotor core 1 and the inner rotor core 4 are both fixedly coupled to the rotor shaft 5 such that the outer rotor core 1 and the inner rotor core 4 rotate together with the rotor shaft 5. When the permanent magnet synchronous motor is arranged, the radial outer side of the outer rotor iron core 1 is arranged at the outer end of the rotor shaft 5, the radial inner side of the inner rotor iron core 4 is arranged at the inner end of the rotor shaft 5, a plurality of tile-shaped permanent magnets 2 are alternately arranged on the outer circular surface of the inner rotor iron core 4, and the magnetizing directions of the two adjacent permanent magnets 2 are opposite. The thickness of the tile-shaped permanent magnet 2 is determined according to the actual working requirement of the motor, and the number of the tile-shaped permanent magnets is determined according to the number of pole pairs.

The inner rotor core 4 is circular ring shaped. The outer contour of the outer rotor iron core 1 is circular, the radius of the outer contour is determined by the actual requirement of the motor, the inner contour of the outer rotor iron core 1 is formed by a group of eccentric arcs which are convex inwards, the number of the eccentric arcs is equal to that of the permanent magnets 2, and the positions of the eccentric arcs correspond to the permanent magnets 2 one by one. Specifically, the number of the eccentric arcs on the outer rotor core 1 isAnd satisfies the relation:whereinAs poles of electric machinesLogarithm. An air gap of the motor is formed between the radial inner side of the outer rotor core 1 and the permanent magnet 2, the hollow cup stator 3 is arranged in the air gap and is fixed on the machine shell, and magnetic flux generated by the permanent magnet 2 forms a closed loop through the outer rotor core 1, the inner rotor core 4 and the air gap between the outer rotor core 1 and the inner rotor core 4.

When the motor is arranged, the circular outline of the outer rotor core 1, the inner outline of the tile-shaped permanent magnet 2 and the inner outline of the inner rotor core 4 are concentrically arranged, and the concentric point is used as the geometric center of the motor (also the geometric center of the rotor). Two end points of each eccentric arc are arranged on an extension line of a connecting line of two side edges of the corresponding permanent magnet 2 and the geometric center of the motor, the circle center of each eccentric arc is arranged on a reverse extension line of a connecting line of the arc-shaped edge of the corresponding permanent magnet 2 and the geometric center of the motor, and the circle center of each eccentric arc is arranged on the radial outer side of the outline of the outer rotor core 1.

As shown in fig. 2, point O is the geometric center of the motor; A. b, two points are two end points of the eccentric arc, O' point is the center of the eccentric arc, and H point is the middle point of the eccentric arc;is the thickness of the permanent magnet;which is the radius of the outer contour of the inner rotor core 4,is the radius of the eccentric arc,the distance from the middle point of the eccentric arc to the geometric center of the motor,the eccentric value is the distance between the center of the eccentric arc and the geometric center of the motor;the radius of the outer contour of the outer rotor iron core.

The two end points A, B of the eccentric arc are on the extension line of the connecting line of the two sides of the corresponding permanent magnet 2 and the geometric center O of the motor, that is, the two sides of the permanent magnet 2 corresponding to the eccentric arc are on the line segments OA and OB.

The circle center of the eccentric arc is on the reverse extension line of the connecting line of the arc-shaped center point of the corresponding permanent magnet 2 and the geometric center of the motor, namely, the O 'point is positioned on the extension line of the line segment OH and positioned outside the radial outer side of the outline of the outer rotor iron core 1, namely, the connecting line O' H of the center point of the eccentric arc and the circle center of the eccentric arc passes through the radial outline of the outer rotor iron core 1.

Meanwhile, the sine wave rotor designed based on the outer rotor core eccentric structure meets the following design regarding dimensions when being arranged:

1) the distance from the middle point of the eccentric arc to the geometric center of the motor isAnd satisfies the relation:in the formulaIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet;

2) the radius of the eccentric arc isAnd satisfies the relation:

in the formulaThe number of pole pairs of the motor is;

3) the distance between the center of the eccentric arc and the geometric center of the motor is an eccentric valueAnd satisfies the relation:。

4) the radius of the circular outline of the outer rotor iron core isAnd satisfies the relation:。

this embodiment 1 uses an inner rotor core outer diameterIs 52mm, and the thickness of the permanent magnet6mm, number of pole pairsFor example, the hollow cup type permanent magnet synchronous motor designed based on the eccentric structure of the outer rotor core is 6, and the outer rotor core is designed as follows:

is composed ofCalculating the distance from the middle point of the eccentric arc to the geometric center of the motorSatisfy the requirement ofIn order to facilitate the processing,preferably 65 mm;

is composed ofDetermining the half of the eccentric arcDiameter of a pipeSatisfy the requirement ofIn order to facilitate the processing,preferably 30 mm;

is composed ofCalculating an eccentricity valueIs 95 mm;

is composed ofDetermining the radius of the circular outer side of the outer rotor coreSatisfy the requirement ofIn order to facilitate the processing,preferably 106 mm.

The motor parameters of the traditional hollow cup type motor are that the outer diameter of an eccentric outer rotor is 106mm, the inner diameter is 65mm, and the number of pole pairs is6 pairs, the outer diameter of the inner rotor is 52mm, the outer diameter of the permanent magnet is 58mm, the thickness is 6mm, and the inner diameter is 52 mm.

Compared with the traditional hollow cup type motor, the air gap magnetic field of the hollow cup type permanent magnet synchronous motor designed based on the outer rotor core eccentric structure is closer to a sine wave. Referring to FIG. 3, the Total Harmonic Distortion (THD) is introduced to evaluate the sinusoidality of the air-gap magnetic field waveformFourier decomposition transform is carried out on the waveform of the gap magnetic field to obtain the amplitude of each order of harmonic wave, and the formula is shown in the specificationTHD is calculated, the smaller the THD, the better the sinusoid. Compared with the traditional coreless motor structure, the invention reduces the THD from 28.6% to 18.2%, reduces the THD by 36.4%, and enables the air gap magnetic field waveform to be closer to a sine wave.

Example 2

Embodiment 2 discloses a sine wave rotor designed based on an outer rotor core eccentric structure, which is used in a hollow cup type sine wave flywheel motor. Referring to fig. 4 and 5, it includes an outer rotor core 1, a permanent magnet 2, a magnetism isolating block 6, a hollow cup stator 3, an inner rotor core 4, and a rotor shaft 5. The outer rotor iron core 1 and the inner rotor iron core 4 are both fixedly connected to the rotor shaft 5, so that the outer rotor iron core 1 and the inner rotor iron core 4 can rotate together with the rotor shaft 5. When the permanent magnet synchronous motor is arranged, the radial outer side of the outer rotor iron core 1 is arranged at the outer end of the rotor shaft 5, the radial inner side of the inner rotor iron core 4 is arranged at the inner end of the rotor shaft 5, a plurality of tile-shaped permanent magnets 2 are alternately arranged on the outer circular surface of the inner rotor iron core 4, the magnetizing directions of the two adjacent permanent magnets 2 are opposite, the thickness of the tile-shaped permanent magnets 2 is determined according to the actual working requirement of the motor, and the number of the tile-shaped permanent magnets is determined according to the number of pole pairs. The magnetic isolation blocks 6 are also tile-shaped and are arranged between two adjacent permanent magnets 2, and the number of the magnetic isolation blocks is the same as that of the permanent magnets.

The inner rotor core 4 is circular ring shaped. The outer rotor iron core 1 has a circular outline and an outline radiusThe inner contour of the outer rotor iron core 1 is determined by actual requirements of the motor, and is formed by a group of eccentric arcs protruding inwards, the number of the eccentric arcs is equal to that of the permanent magnets 2, and the positions of the eccentric arcs correspond to the permanent magnets 2 one by one. The number of the eccentric arcs on the outer rotor iron core 1 isAnd satisfies the relation:whereinThe number of pole pairs of the motor is shown. An air gap of the motor is formed between the radial inner side of the outer rotor core 1 and the permanent magnet 2, the hollow cup stator 3 is arranged in the air gap and is fixed on the machine shell, and magnetic flux generated by the permanent magnet 2 forms a closed loop through the outer rotor core 1, the inner rotor core 4 and the air gap between the outer rotor core 1 and the inner rotor core 4.

When the motor is arranged, the circular outline of the outer rotor core 1, the inner outline of the permanent magnet 2 and the inner outline of the inner rotor core 4 are concentrically arranged, and the concentric point is used as the geometric center of the motor (also the geometric center of the rotor). Two end points of the eccentric arc are positioned on an extension line of a connecting line of the middle point of the tile-shaped edges of the magnetic separation blocks 6 at two sides of the corresponding permanent magnet 2 and the geometric center of the motor, the circle center of the eccentric arc is positioned on a reverse extension line of the connecting line of the middle point of the arc-shaped edge of the corresponding permanent magnet 2 and the geometric center of the motor, and the circle center of the eccentric arc is positioned on the radial outer side of the outer rotor iron core 1 outline, namely the connecting line of the middle point of the eccentric arc and the circle center of the eccentric arc passes through the radial outer outline of the outer rotor iron core 1.

As shown in fig. 5, point O is the geometric center of the motor; A. b, two points are two end points of the eccentric arc, O' point is the center of the eccentric arc, and H point is the middle point of the eccentric arc; C. d, E is the middle point of the tile-shaped edge of the magnetic isolation blocks at the two sides of the permanent magnet 2,is the thickness of the permanent magnet 2;the radius of the outer contour of the inner rotor iron core 4;is the radius of the eccentric arc;from the middle point of the eccentric arc to the geometric center of the motorThe distance of (a) to (b),the eccentric value is the distance between the center of the eccentric arc and the geometric center of the motor;the radius of the outer contour of the outer rotor iron core 1;is the inner diameter of the tile-shaped magnetic isolating block 6,the outer diameter of the tube is the same as the diameter of the tube,is its opening angle;is the tile-shaped opening angle of the permanent magnet 2.

The two end points A, B of the eccentric arc are on the extension line of the connecting line of the middle point C, D of the tile-shaped edge of the magnetic isolating block 6 at the two sides of the corresponding permanent magnet 2 and the geometric center O of the motor, namely A is on the extension line of the line segment OC and B is on the extension line of the line segment OD.

The center of the eccentric arc is on the extension line of the connecting line of the arc-shaped center point of the corresponding permanent magnet 2 and the geometric center of the motor, namely, the point O 'is positioned on the extension line of the line segment OH and positioned on the radial outer side of the outline of the outer rotor iron core 1, namely, the connecting line O' H of the arc-shaped center point and the center of the arc passes through the radial outline of the outer rotor iron core 1.

Meanwhile, the sine wave rotor designed based on the outer rotor core eccentric structure meets the following design regarding dimensions when being arranged:

1) the tile-shaped inner diameter of the magnetic isolation block isAnd satisfies the relation:the tile-shaped outer diameter isAnd satisfies the relation:whereinIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet 2;

2) the tile-shaped opening angle of the magnetic isolation block isAnd satisfies the relation:tile-shaped opening angle of permanent magnet 2Satisfy the relationWhereinThe number of pole pairs of the motor is;

3) the number of eccentric arcs on the outer rotor iron core isAnd satisfies the relation:；

4) the distance from the middle point of the eccentric arc to the geometric center of the motor isAnd satisfies the relation:in the formulaIs the radius of the outer contour of the inner rotor iron core,is the thickness of the permanent magnet;

5) the radius of the eccentric arc isAnd satisfies the relation:

whereinThe coefficient of the magnetic isolation block satisfies the relation:；

6) the distance between the center of the eccentric arc and the geometric center of the motor is an eccentric valueAnd satisfies the relation:。

7) the radius of the circular outline of the outer rotor iron core isAnd satisfies the relation:。

this embodiment 2 uses an inner rotor core outer diameterIs 45mm, and the thickness of the permanent magnet6mm, number of pole pairsFor example, the hollow cup type sine wave motor designed based on the eccentric structure of the outer rotor core is 6, and the magnetic isolation block and the outer rotor core are designed:

is composed ofObtaining the tile-shaped inner diameter of the magnetic separation blockIs of the formulaObtaining the tile-shaped outer diameter of the magnetic separation block；

Is composed ofDewar tile type opening angleSatisfy the requirement ofIn order to facilitate the processing and the manufacturing,preferably takes on a value ofIs of the formulaDetermining the tile-shaped opening angle of the permanent magnet 2Is composed of(28.5°)；

Is composed ofCalculating the distance from the midpoint of the single eccentric arc to the geometric center of the motorSatisfy the requirement ofIn order to facilitate the processing,preferably 58 mm;

is composed ofDetermining the radius of a single eccentric arcSatisfy the requirement ofIn order to facilitate the processing,preferably 25 mm;

is composed ofCalculating an eccentricity value83mm, by formulaDetermining the radius of the circular outer side of the outer rotor coreSatisfy the requirement ofIn order to facilitate the processing,preferably 95 mm.

The motor parameters of the traditional hollow cup type motor are that the outer diameter of an eccentric outer rotor is 95mm, the inner diameter is 58mm, and the number of pole pairs is6 pairs, the outer diameter of the inner rotor is 45mm, the outer diameter of the permanent magnet is 51mm, the thickness is 6mm, and the inner diameter is 45 mm. Compared with the traditional hollow cup type motor, the air gap field of the hollow cup type sine wave motor with the magnetic isolating blocks designed based on the outer rotor core structure is closer to a sine wave. Referring to the attached figure 6, the sine of the air-gap magnetic field waveform is evaluated by introducing a Total Harmonic Distortion (THD), the air-gap magnetic field waveform is subjected to Fourier decomposition transformation to obtain the amplitude of each order of harmonic, and the formula is shownTHD is calculated, the smaller the THD, the better the sinusoid. Compared with the traditional coreless motor structure, the invention reduces THD from 29.7% to 16.4%, reduces THD by 41.4%, and makes the air gap magnetic field waveform closer to sine wave.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.