CN215681953U - Motor - Google Patents

Abstract

A motor having an inner rotor and an outer stator is provided. The rotor lamination of rotor stacks the setting along the direction of center pin, and includes main part, a plurality of peripheral part and a plurality of arc portion of repairing. The center of the main body part is opposite to the central axis, the plurality of peripheral parts are arranged on the peripheral edge of the main body part, the plurality of peripheral parts are arranged in a radial mode, the plurality of peripheral parts are assembled to form a circumscribed circle, and the circumscribed circle has a radius distance with the central axis. The arc trimming part is concavely arranged according to an arc line. The middle point of the arc line is spatially corresponding to the peripheral edge part, and the two end points are symmetrically arranged at two opposite ends of the arc line. The midpoint has a first distance from the central axis and the end point has a second distance from the central axis. The first distance is greater than or equal to the radius distance and less than 1.5 times the radius distance, and the second distance is greater than 0.5 times the radius distance and less than the radius distance.

Description

Motor

Technical Field

The present invention relates to a motor, and more particularly, to a motor having an inner rotor and an outer stator, wherein the rotor includes a spoke type Interior Permanent Magnet (IPM) disposed thereon for minimizing cogging torque and reducing manufacturing sensitivity.

Background

Generally, a permanent magnet motor or a structure of a permanent magnet motor includes a rotor and a stator. The stator includes windings disposed thereon. The rotor includes permanent magnets disposed thereon and is formed by stacking a plurality of rotor laminations, such as, but not limited to, silicon steel sheets. Thus, the magnetic force generated between the stator and the rotor can rotate the rotor.

In order to improve the efficiency or performance of the motor, it is necessary to increase the torque ratio generated by a unit current. The conventional rotor including the spoke type interior permanent magnet has a higher magnetic flux density than the surface type permanent magnet motor, but causes an excessive cogging torque to be generated. On the other hand, the surface type permanent magnet motor can achieve the effect of reducing torque by trimming an arc shape around the rotor without changing the position of the magnet or adjusting the shape of the rotor lamination. However, conventional rotors having a spoke-type interior permanent magnet motor cannot achieve the same effect by simply trimming the arc around the rotor. Since the characteristics of the spoke type interior permanent magnet motor are affected by the minimum manufacturing thickness of the rotor laminations and the magnet location, it is not easy to apply the design of the spoke type interior permanent magnet to the conventional motor.

In designing a spoke-type interior permanent magnet rotor, in order to ensure that output torque performance (greater torque) can be maintained under optimized torque ripple conditions (smoother operation), it is necessary to balance the depth of the rotor arc portion, the arrangement position of the magnets, and the thickness of the rotor laminations at the same time. If the design is performed by using simulation analysis software, it takes a long time to obtain the required design value to balance the performance because of the large number of variable factors involved. Furthermore, the dimensional parameters for the rotor are coupled to each other, which further increases the difficulty of calculating the optimal rotor size.

In view of the above, it is desirable to provide a motor with an outer stator having an inner rotor, wherein the rotor includes a spoke-type built-in permanent magnet disposed thereon to solve the drawbacks of the prior art.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide a motor having an outer stator with an inner rotor, the rotor of which includes a spoke-type built-in permanent magnet disposed thereon for minimizing cogging torque and reducing manufacturing sensitivity. The positions of the concealed permanent magnets and the arcuate arc trimming portion are designed to minimize cogging torque with an arc and minimum manufactured thickness of the rotor laminations. Therefore, the motor counter-electromotive force (motor-electromotive force) and the synthesized running torque (residual running torque) can be reduced, and the effect of improving the motor efficiency is achieved.

Another object of the present invention is to provide a motor having an outer stator with an inner rotor, wherein the rotor includes a spoke-type built-in permanent magnet disposed thereon. An arc is used to limit the arc trimming part of the rotor, and the spoke type built-in permanent magnet is arranged according to the minimum manufacturing thickness of the rotor lamination, so that the position of the built-in permanent magnet can be easily designed. Therefore, the influence of the cogging torque of the motor can be eliminated, and the effect of improving the efficiency of the motor is achieved.

It is still another object of the present invention to provide a motor having an outer stator with an inner rotor, wherein the rotor defines the positions of the arc-shaped portion of the rotor body and the inner permanent magnet by using an arc line, and the design of the rotor lamination in the rotor can be changed to optionally select the inner permanent magnet to have an open end or a closed end. Therefore, the rotor can provide the optimized output torque performance, and the efficiency of the motor is improved.

It is yet another object of the present invention to provide a motor having an outer stator with an inner rotor, wherein the rotor lamination and the rotor are designed to be more simplified and the product development speed is increased by optimizing the size and parameters.

To achieve the above objective, the present invention provides a motor having an outer stator with an inner rotor, wherein the rotor is sleeved in the stator, and an air gap is formed between the rotor and the stator, wherein the rotor rotates relative to the stator about a central axis. The rotor includes a plurality of rotor laminations and a plurality of permanent magnets. A plurality of rotor laminations are stacked along the direction of a central shaft, wherein each rotor lamination comprises a main body part, a plurality of peripheral parts and a plurality of arc trimming parts, wherein the center of the main body part is opposite to the central axis, a plurality of peripheral parts are arranged on the peripheral edge of the main body part, the peripheral parts are arranged in a radial shape, and a plurality of peripheral portions are assembled to form a circumscribed circle having a radial distance from the central axis, wherein the arc trimming portions are respectively formed by being concavely arranged from a plurality of peripheral portions according to an arc line, the arc line is provided with a midpoint and two end points, the midpoint is positioned in the center of the arc line and corresponds to the peripheral portions in space, the two end points are symmetrically arranged at two opposite ends of the arc line, wherein the center point has a first distance from the central axis, and the two end points have a second distance from the central axis, wherein the first distance is greater than or equal to the radius distance and less than 1.5 times the radius distance, and the second distance is greater than 0.5 times the radius distance and less than the radius distance. The main part that a plurality of permanent magnets run through a plurality of rotor lamination along the direction of center pin, and encircle the center of main part and be radial arrangement setting, each permanent magnet is along a radial extension, and wherein a plurality of permanent magnets and a plurality of peripheral part are arranged in turn, and the terminal point of pitch arc corresponds the permanent magnet in space.

In one embodiment, each permanent magnet is arranged along the central axis and the corresponding end point, and has a first end portion and a second end portion opposite to each other, the first end portion is adjacently arranged at the corresponding end point, and the second end portion faces the central axis.

In one embodiment, the plurality of rotor laminations include at least one open rotor lamination or at least one closed rotor lamination, wherein the first ends of the plurality of permanent magnets remain at least partially exposed when the plurality of permanent magnets extend through the open rotor lamination in the direction of the central axis, and wherein the first ends of the plurality of permanent magnets remain unexposed when the plurality of permanent magnets extend through the closed rotor lamination in the direction of the central axis.

In an embodiment, the open-type rotor lamination includes a plurality of first holding portions spatially corresponding to the plurality of permanent magnets, wherein the first holding portions are disposed at two adjacent arc trimming portions, and each first holding portion is configured to fix the corresponding permanent magnet and maintain the first end of the corresponding permanent magnet to be at least partially exposed.

In one embodiment, each rotor lamination has a minimum manufacturing thickness, and the first holding portion has a first thickness along the radial direction, and the first thickness ranges from one time of the minimum manufacturing thickness to two times of the minimum manufacturing thickness.

In an embodiment, the closed rotor lamination includes a plurality of second holding portions, the plurality of second holding portions spatially correspond to the plurality of permanent magnets, wherein the second holding portions are disposed on two adjacent arc trimming portions, and each second holding portion is configured to fix the corresponding permanent magnet and maintain the first end of the corresponding permanent magnet not to be exposed.

In one embodiment, each rotor lamination has a minimum manufacturing thickness, and the second holding portion has a second thickness along the radial direction, wherein the second thickness ranges from one to two times the minimum manufacturing thickness.

In one embodiment, the plurality of rotor laminations includes P open rotor laminations and Q closed rotor laminations, wherein P, Q is an integer, P is greater than or equal to Q, Q is greater than or equal to 1, and P is 9 times Q.

In one embodiment, the number of the plurality of permanent magnets is 2M, M is an integer, and M is greater than or equal to 2.

In one embodiment, two adjacent permanent magnets of the plurality of permanent magnets have opposite magnetic properties.

In view of the foregoing, it will be apparent to those skilled in the art from this disclosure that the following detailed description and accompanying drawings set forth herein can be taken to provide a more complete understanding of the present invention.

Drawings

FIG. 1 is a perspective view of the motor of the present invention;

fig. 2 is a perspective view showing a rotor according to a first embodiment of the present invention;

FIG. 3 is a top view of a rotor disclosing a first embodiment of the present disclosure;

FIG. 4 is a partial enlarged view of the area P1 of FIG. 3;

FIG. 5 shows the relative distances from the central axis of the rotor to the arc and to the circumcircle in the first embodiment of the present invention;

FIG. 6 is a perspective view showing a rotor according to a second embodiment of the present invention;

FIG. 7 is a top view of a rotor disclosing a second embodiment of the present disclosure;

FIG. 8 is a partial enlarged view of the area P2 of FIG. 7;

FIG. 9 shows the relative distances from the central axis of the rotor to the arc and to the circumcircle in the second embodiment of the present invention;

fig. 10 is a perspective view showing a rotor according to a third embodiment of the present invention.

[ notation ] to show

1. 1a, 1 b: rotor

2a, 2 b: rotor lamination

10: main body part

11: peripheral edge part

12: arc trimming part

13: first holding part

13 a: second holding part

20: permanent magnet

20 a: first end part

20 b: second end portion

3: motor with a stator having a stator core

4: stator

41: hollow part

42: winding wire

A1, A2: endpoint

B: midpoint

C: center shaft

D1: first distance

D2: second distance

G: air gap

k: arc line

r: circumscribed circle

P1, P2: region(s)

R: radial distance

T1: a first thickness

T2: second thickness

TM: minimum thickness of manufacture

Detailed Description

Exemplary embodiments that embody features and advantages of this disclosure are described in detail below in the detailed description. It will be understood that the present disclosure is capable of various modifications without departing from the scope of the disclosure, and that the description and drawings are to be regarded as illustrative in nature, and not as restrictive.

Fig. 1 shows a three-dimensional structure of the motor of the present invention. Fig. 2 is a perspective view showing a rotor according to a first embodiment of the present invention. Fig. 3 is a top view of a rotor disclosing a first embodiment of the present disclosure. Fig. 4 is a partial enlarged view showing the region P1 in fig. 3. Fig. 5 shows the relative distances from the central axis of the rotor to the arc and to the circumcircle in the first embodiment of the present invention. In the present embodiment, the motor 3 includes a rotor 1 and a stator 4. The combination of the rotor 1 and the stator 4 is completed by adopting a mode of an outer stator and an inner rotor. In the present embodiment, the stator 4 has a hollow portion 41 and a plurality of windings 42 correspondingly surrounding a plurality of teeth thereof, and the rotor 1 is disposed in the hollow portion 41 of the stator 4. In the present embodiment, the rotor 1 rotates around a central axis C as a center relative to the stator 4, wherein the central axis C of the rotor 1 is configured as a rotating axis of the motor 1. In the present embodiment, an air gap G is formed between the rotor 1 and the stator 4. Preferably, the width of the air gap G is 0.25mm to 1.0mm, but the disclosure is not limited thereto. In the present embodiment, the rotor 1 includes a plurality of rotor laminations 2a and a plurality of permanent magnets 20. Wherein the plurality of rotor laminations 2a may be, for example and without limitation, silicon steel plates, each rotor lamination 2a being manufactured according to a minimum manufacturing thickness TM. In the present embodiment, the minimum manufacturing thickness TM of each rotor lamination 2a is, for example, in the range of 0.35 cm to 0.5 cm. A plurality of rotor laminations 2a are stacked in the direction of a central axis C. The central axis C is a rotation axis of the rotor 1 in the motor, and the rotor 1 rotates around the central axis C. In addition, the central axis C can also be regarded as the symmetry center of the rotor 1 and the rotor lamination 2 a. Of course, in the embodiment, the number, the spacing distance and the single thickness of the rotor laminations 2a can be adjusted according to the actual requirement, and the present disclosure is not limited thereto. In another embodiment, the single piece thickness of the rotor lamination 2a is greater than the minimum manufacturing thickness TM. The present disclosure is not limited thereto.

In the present embodiment, each rotor lamination 2a includes a main body 10, a plurality of peripheral portions 11, and a plurality of arc trimming portions 12. Wherein the central pair of main bodies 10 is located at the central axis C of the rotor 1. In the present embodiment, a plurality of peripheral portions 11 are disposed on the outer periphery of the main body 10, a plurality of peripheral portions 12 are arranged radially, and the plurality of peripheral portions 11 are assembled to form a circumscribed circle r. In the present embodiment, the rotor 1 includes, for example, ten permanent magnets 20, which penetrate the main body 10 of the plurality of rotor laminations 2a along the direction of the central axis C and are arranged in a radial arrangement around the center of the main body 10. In the present embodiment, any two adjacent permanent magnets 20 have opposite magnetic properties. For example, of the ten permanent magnets 20, five N-pole permanent magnets 20 and five P-pole permanent magnets 20 are alternately arranged. In other embodiments, the rotor 1 has, for example, 2M permanent magnets 20, where M is a whole and is greater than or equal to 2. Of course, the present invention is not limited thereto.

On the other hand, in the present embodiment, the circumscribed circle R formed by the plurality of peripheral edge portions 11 is further formed with a radial distance R from the central axis C. In the present embodiment, the arc trimming portions 12 are recessed from the peripheral portions 11 according to an arc k. The arc k has a midpoint B located at the center of the arc k and spatially corresponding to the peripheral portion 11, and two end points a1 and a2 symmetrically disposed at two opposite ends of the arc k, a1 and a 2. In the present embodiment, the midpoint B has a first distance D1 from the central axis C, and the two end points a1, a2 have a second distance D2 from the central axis C, respectively. Wherein the first distance D1 is greater than and less than 1.5 times the radial distance R and the second distance D2 is greater than 0.5 times and less than the radial distance R. Therefore, the obtained rotor 1 can reduce the motor counter-electromotive force (motor-electromotive force) and the synthesized running torque (residual running torque), and achieve the effect of improving the motor efficiency. The practical effects of optimizing the size and improving the motor efficiency will be described in detail later.

In the present embodiment, each of the permanent magnets 20 extends along a radial direction, i.e., along the central axis C and the corresponding endpoint arc k, the endpoint a1/a2, and each of the permanent magnets 20 has a first end 20a and a second end 20b opposite to each other, wherein the first end 20a is disposed adjacent to the corresponding endpoint a1/a2, and the second end 20b faces the central axis C. In the present embodiment, the plurality of rotor laminations 2a is, for example, an open-type rotor lamination 2 a. When the plurality of permanent magnets 20 penetrate the plurality of rotor laminations 2a along the direction of the central axis C, each permanent magnet 20 extends radially outward, and the first end 20a of the plurality of permanent magnets 20 corresponding to the end point a1/a2 is further maintained at least partially exposed. In the present embodiment, each open-type rotor lamination 2a includes a plurality of first holding portions 13, the plurality of first holding portions 13 spatially correspond to the plurality of permanent magnets 20, wherein the first holding portions 13 are disposed on two adjacent arc trimming portions 12, and each first holding portion 13 is configured to fix the corresponding permanent magnet 20 and maintain the first end portion 20a of the corresponding permanent magnet 20 at least partially exposed. In the present embodiment, each open-type rotor lamination 2a has a minimum manufacturing thickness, and the first holding portion 13 has a first thickness T1 along the radial direction, wherein the first thickness T1 and the minimum manufacturing thickness may be equal, for example. In other embodiments, the first thickness T1 preferably ranges from one to two times the minimum manufacturing thickness TM, i.e., TM < T1 < 2 TM. Of course, the present invention is not limited thereto. In the present embodiment, when the first holding portion 13 is utilized to fix the opposite permanent magnets 20, the first end 20a of the permanent magnet 20 adjacent to the corresponding end point a1/a2 is further exposed to each rotor lamination 2a, i.e., the permanent magnet 20 is fixed by the plurality of open-type rotor laminations 2 a. The open-type rotor lamination 2a is formed by a body portion 10, a peripheral portion 11, an arc trimming portion 12 and a first holding portion 13.

It is noted that the present case utilizes an arc k and the minimum manufacturing thickness TM of the rotor lamination 2a to design the positions of the permanent magnets 20 and the arc trimming portion 12 to minimize cogging torque. The rotor lamination 2a is centered on the central axis C, the center forming a first distance D1 from the midpoint B of the arc k and the center forming a second distance D2 from the ends a1, a 2. In the present embodiment, the first distance D1 is more than the radius distance R and less than 1.5 times the radius distance R, and the second distance D2 is more than 0.5 times the radius distance R and less than the radius distance R. The following table compares the output torque ripple with the cogging torque ratio of a conventional rotor without the arc trimming portion structure and an open rotor with different arc trimming portions. The radius distance R is, for example, 28.85mm, but not limited thereto.

Watch 1

As shown in table one, the rotor lamination 2a of the present invention designs the positions of the arc trimming portion 12 and the permanent magnet 20 according to the arc k to construct the rotor 1, so that a smaller cogging torque rate can be obtained compared to a conventional rotor without the arc trimming portion structure. In other words, the present invention provides the arc line k to inwardly recess the circumferential edge 11 of the circumscribed circle r to form the arc trimming portion 12, which helps to minimize cogging torque of the rotor 1. Therefore, the back electromotive force of the motor can be reduced, the resultant running torque can be reduced, and the effect of improving the motor efficiency can be achieved.

Fig. 6 is a perspective view showing a rotor according to a second embodiment of the present invention. Fig. 7 is a top view of a rotor disclosing a second embodiment of the present disclosure. Fig. 8 is a partial enlarged view showing the region P2 in fig. 7. Fig. 9 shows the relative distances from the central axis of the rotor to the arc and to the circumcircle in the second embodiment of the present invention. In the second embodiment of the present disclosure, the rotor 1a is similar to the rotor 1 shown in fig. 1 to 5, and the same reference numerals refer to the same elements, structures and functions, which are not described herein again. Unlike the aforementioned embodiment in which the rotor 1 is formed by the open-type rotor lamination 2a, in the present embodiment, the rotor 1a is constructed by, for example, a plurality of closed-type rotor laminations 2 b. When the plurality of permanent magnets 20 penetrate the plurality of rotor laminations 2b along the central axis C, each permanent magnet 20 extends in a radial direction, the first end 20a of the permanent magnet 20 corresponds to the end point a1/a2, the second end 20b of the permanent magnet 20 faces the central axis C, and the first ends 20a of the permanent magnets 20 corresponding to the end points a1/a2 are all not exposed. In the present embodiment, each of the closed rotor laminations 2b includes a plurality of second holding portions 13a, the plurality of second holding portions 13a spatially correspond to the plurality of permanent magnets 20, wherein the second holding portions 13a are disposed on two adjacent arc trimming portions 12, and each of the second holding portions 13a is configured to fix the corresponding permanent magnet 20 and maintain the first end portion 20a of the corresponding permanent magnet 20 not exposed. In the present embodiment, each of the enclosed rotor laminations 2b has a minimum manufactured thickness TM, and the second holding portion 13 has a second thickness T2 along the radial direction, wherein the first thickness T2 and the minimum manufactured thickness TM may be equal to each other, for example. In other embodiments, the second thickness T2 preferably ranges from one to two times the minimum manufacturing thickness TM, i.e., TM < T2 < 2 TM. Of course, the present invention is not limited thereto. In the present embodiment, when the second holding portion 13a is used to fix the opposite permanent magnets 20, the first end portion 20a of the permanent magnet 20 adjacent to the corresponding end point a1/a2 is further kept not exposed to each rotor lamination 2b, i.e., the permanent magnet 20 is fixed by the plurality of enclosed rotor laminations 2 b. The open-type rotor lamination 2b is formed by a body portion 10, a peripheral portion 11, an arc trimming portion 12 and a second holding portion 13 a.

It is noted that the present case utilizes an arc k and the minimum manufacturing thickness TM of the rotor lamination 2b to design the positions of the permanent magnets 20 and the arc trimming portion 12 to minimize cogging torque. The rotor lamination 2B is centered on the central axis C, the center forming a first distance D1 from the midpoint B of the arc k, and the center forming a second distance D2 from the ends a1, a 2. In the present embodiment, the first distance D1 is more than the radius distance R and less than 1.5 times the radius distance R, and the second distance D2 is more than 0.5 times the radius distance R and less than the radius distance R. The second list is the relationship between the output torque ripple and cogging torque ratio of conventional rotors without arc trimming structure and closed rotors with different arc trimming sizes. The radius distance R is, for example, 28.85mm, but not limited thereto.

Watch two

As shown in table two, the rotor lamination 2b of the present invention designs the positions of the arc trimming portion 12 and the permanent magnet 20 according to the arc k to construct the rotor 1a, so that a smaller cogging torque rate can be obtained compared with a conventional rotor without the arc trimming portion structure. In other words, the present invention provides the arc line k to inwardly recess the circumferential edge 11 of the circumscribed circle r to form the arc trimming portion 12, which helps to minimize cogging torque of the rotor 1 a. Therefore, the back electromotive force of the motor can be reduced, the resultant running torque can be reduced, and the effect of improving the motor efficiency can be achieved.

Fig. 10 is a perspective view showing a rotor according to a third embodiment of the present invention. In the third embodiment of the present disclosure, the rotor 1b is similar to the rotor 1 shown in fig. 1 to 5 and the rotor 1a shown in fig. 6 to 9, and the same reference numerals refer to the same elements, structures and functions, which are not described herein again. In the present embodiment, the rotor 1b is composed of a plurality of open-type rotor laminations 2a and a plurality of closed-type rotor laminations 2 b. It should be noted that the number and arrangement of the open-type rotor laminations 2a and the closed-type rotor laminations 2b can be adjusted according to the practical application requirement, and the present disclosure is not limited thereto. In the present embodiment, the rotor 1b includes three closed-type rotor laminations 2b stacked on the top, bottom and center of the rotor 1 b. And for example nine open rotor laminations 2a are stacked between both closed rotor laminations 2 b. In the present embodiment, when the plurality of permanent magnets 20 penetrate the open-type rotor lamination 2a along the direction of the central axis C, the first ends 20a of the plurality of permanent magnets 20 are maintained at least partially exposed. In addition, when the plurality of permanent magnets 20 penetrate the closed-type rotor lamination 2b in the direction of the central axis C, the first ends 20a of the plurality of permanent magnets 20 remain unexposed. In one embodiment, the rotor 1b comprises P open-type rotor laminations 2a and Q closed-type rotor laminations 2b, wherein P, Q is an integer, P is greater than or equal to Q, and Q is greater than or equal to 1. In other embodiments, the rotor 1b in fig. 10 is omitted from the closed rotor lamination 2b at the center, and is constructed by stacking the closed rotor laminations 2b arranged at the top and the bottom and stacking eighteen open rotor laminations 2a arranged between the two closed rotor laminations 2 b. That is, P is 9 times Q, the output torque performance of the rotor 1b can be optimized while ensuring the stability of the entire structure. Of course, the present disclosure is not limited thereto and will not be described in detail.

In summary, the present invention provides a motor having an outer stator with an inner rotor, wherein the rotor includes a spoke-type built-in permanent magnet disposed thereon for minimizing cogging torque and reducing manufacturing sensitivity. The positions of the concealed permanent magnets and the arcuate arc trimming portion are designed to minimize cogging torque with an arc and minimum manufactured thickness of the rotor laminations. Therefore, the back electromotive force and the synthetic running torque of the motor can be reduced, and the effect of improving the efficiency of the motor is achieved. Furthermore, an arc is used to limit the arc trimming part in the rotor, and the spoke type built-in permanent magnet is arranged according to the minimum manufacturing thickness of the rotor lamination, so that the position of the built-in permanent magnet can be easily designed. Therefore, the influence of the cogging torque of the motor can be eliminated, and the effect of improving the efficiency of the motor is achieved. In addition, by using an arc line to define the position of the arc-shaped forming part of the rotor main body part and the built-in permanent magnet, the design of the rotor lamination in the rotor can be changed, and the built-in permanent magnet can be freely selected to have an open end or a closed end. Therefore, the rotor can provide the optimized output torque performance, and the efficiency of the motor is improved. In addition, the rotor lamination and the rotor suitable for the same can further simplify the design and accelerate the product development speed by optimizing the size and parameters.

Various modifications may be made by those skilled in the art without departing from the scope of the appended claims.

Claims (10)

1. A motor comprises a stator and a rotor, characterized in that the rotor is sleeved in the stator, and an air gap is formed between the rotor and the stator, wherein the rotor rotates relative to the stator by taking a central shaft as a center, and the rotor comprises:

a plurality of rotor laminations stacked along the direction of the central axis, wherein each rotor lamination comprises a main body portion, a plurality of peripheral portions and a plurality of arc trimming portions, wherein the center of the main body portion is opposite to the central axis, the plurality of peripheral portions are arranged on the outer periphery of the main body portion, the plurality of peripheral portions are arranged in a radial shape, the plurality of peripheral portions are assembled to form an outer circle, the outer circle has a radius distance with the central axis, the plurality of arc trimming portions are respectively formed by being concavely arranged from the plurality of peripheral portions according to an arc line, the arc line has a middle point and two end points, the middle point is positioned in the center of the arc line and corresponds to the peripheral portions in space, the two end points are symmetrically arranged at two opposite ends of the arc line, the middle point has a first distance with the central axis, the two end points have a second distance with the central axis, and the first distance is greater than or equal to the radius distance and less than 1.5 times of the radius distance, the second distance is greater than 0.5 times the radial distance and less than the radial distance; and

the permanent magnets penetrate through the main body parts of the rotor laminations in the direction of the central shaft and are arranged in a radial mode around the center of the main body part, each permanent magnet extends in the radial direction, the permanent magnets and the peripheral parts are arranged in an alternating mode, and the end points of the arc lines correspond to the permanent magnets in space.

2. The motor as claimed in claim 1, wherein each of the permanent magnets is arranged along the central axis and the corresponding end point and has a first end portion and a second end portion opposite to each other, the first end portion being adjacent to the corresponding end point, and the second end portion facing the central axis.

3. The motor of claim 2, wherein the plurality of rotor laminations comprises at least one open rotor lamination or at least one closed rotor lamination, wherein the first ends of the plurality of permanent magnets remain at least partially exposed when the plurality of permanent magnets extend through the open rotor lamination in the direction of the central axis, and wherein the first ends of the plurality of permanent magnets remain unexposed when the plurality of permanent magnets extend through the closed rotor lamination in the direction of the central axis.

4. The motor of claim 3, wherein the open-type rotor lamination comprises a plurality of first holding portions spatially corresponding to the plurality of permanent magnets, wherein the first holding portions are disposed at two adjacent arc trimming portions, each of the first holding portions is configured to fix the corresponding permanent magnet and maintain the first end of the corresponding permanent magnet at least partially exposed.

5. The motor as claimed in claim 4, wherein each of the rotor laminations has a minimum manufactured thickness, the first holding portion has a first thickness in a radial direction, and the first thickness ranges from one time the minimum manufactured thickness to two times the minimum manufactured thickness.

6. The motor as claimed in claim 3, wherein the closed rotor lamination includes a plurality of second holding portions spatially corresponding to the plurality of permanent magnets, wherein the second holding portions are disposed at two adjacent arc trimming portions, and each of the second holding portions is configured to fix the corresponding permanent magnet and maintain the first end of the corresponding permanent magnet not to be exposed.

7. The motor as claimed in claim 6, wherein each of the rotor laminations has a minimum manufactured thickness, the second holding portion has a second thickness in a radial direction, and the second thickness ranges from one time the minimum manufactured thickness to two times the minimum manufactured thickness.

8. The motor as claimed in claim 3, wherein the plurality of rotor laminations includes P open rotor laminations and Q closed rotor laminations, wherein P, Q is an integer, P is greater than or equal to Q, and Q is greater than or equal to 1, wherein P is 9 times Q.

9. The motor as claimed in claim 1, wherein the number of the plurality of permanent magnets is 2M, M is an integer, and M is 2 or more.

10. The motor of claim 1, wherein two adjacent ones of the plurality of permanent magnets have opposite magnetic properties.

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