CN117767611A - Rotor punching sheet, rotor, motor, compressor and refrigeration equipment - Google Patents

Abstract

The invention discloses a rotor punching sheet, a rotor, a motor, a compressor and refrigeration equipment, wherein the rotor punching sheet is provided with an outer periphery, the outer periphery comprises a plurality of punching sheet edges, two ends of each punching sheet edge are respectively arranged on two adjacent q axes of the rotor punching sheet, and the distance between each punching sheet edge and the rotation center of the rotor punching sheet in the first periphery of the outer periphery is in a reduced change trend. The technical scheme of the invention aims to reduce vibration and noise generated when the motor operates.

Description

Rotor punching sheet, rotor, motor, compressor and refrigeration equipment

Technical Field

The invention relates to the technical field of rotor punching sheets, in particular to a rotor punching sheet, a rotor, a motor, a compressor and refrigeration equipment.

Background

At present, the motor includes stator and rotor, the rotor includes the rotor towards the piece, the rotor towards the piece has the peripheral, the peripheral is circular setting, the stator includes stator yoke portion, and locate a plurality of stator tooth portions of stator yoke portion, the stator tooth portion has the tooth face opposite with the peripheral of rotor towards the piece, the tooth face is the circular arc face around the axis of rotation of rotor, the distance of the outer peripheral of rotor towards the circular arc face is equal, this makes the motor can produce great vibration when running, thereby produce great noise.

Disclosure of Invention

The main object of the present invention is to provide a rotor punching sheet, which aims to reduce vibration and noise generated during the operation of a motor.

In order to achieve the above purpose, the rotor punching sheet provided by the invention has an outer periphery, the outer periphery comprises a plurality of punching sheet edges, two ends of each punching sheet edge are respectively arranged on two adjacent q axes of the rotor punching sheet, and the distance between each punching sheet edge and the rotation center of the rotor punching sheet in the first periphery of the outer periphery is in a reduced change trend.

Optionally, the edge of the punching sheet is provided with a first end point and a second end point, the distance between the rotation center and the first end point is R1, the distance between the rotation center and the second end point is R2, the distance between the rotation center and the midpoint of the edge of the punching sheet is R3, the rotor punching sheet is used for being arranged in an inner hole of a stator, the radius of the inner hole is R, R1 is more than R3 and less than R2 is more than R;

the difference between R3 and R1 is consistent with the difference between R2 and R3; and/or R2-R1 < 2 (R-R3); and/or R-R3 is more than or equal to 0.4mm and less than or equal to 0.7mm.

Optionally, the area of the area surrounded by the circle with the rotation center as the center and the radius R3 is consistent with the area of the area surrounded by the outer periphery of the rotor punching sheet.

Optionally, the edge of the punching sheet is arranged in an arc line;

or, the punching sheet edge comprises a plurality of straight line segments and/or a plurality of arc segments.

Optionally, the rotor punching sheet is provided with a mounting hole for mounting the permanent magnet, and the mounting hole is arranged in a V shape, a U shape, a W shape, an I shape or a straight shape.

The invention also provides a rotor which comprises a plurality of rotor punching sheets.

The invention also proposes a motor comprising:

a stator; and

the rotor is rotatably arranged on the stator.

Optionally, the number of stator slots of the stator is Q, the pole pair number of the rotor is P, the phase number of the motor is m, and Q/2Pm is less than 1.

The invention also provides a compressor comprising the motor.

The invention also provides refrigeration equipment comprising the compressor.

In the technical scheme of the invention, the rotor punching sheet is provided with an outer periphery, the outer periphery comprises a plurality of punching sheet edges, two ends of each punching sheet edge are respectively arranged on two adjacent q axes of the rotor punching sheet, and the distance between each punching sheet edge and the rotation center of the rotor punching sheet in the first periphery of the outer periphery is in a reduced change trend. It should be noted that, the first circumferential direction is shown in the E direction in the drawing, and it is understood that the first circumferential direction may be clockwise, or counterclockwise, and E in the drawing illustrates the present embodiment by taking the counterclockwise direction as an example. Thus, when the motor comprises a stator and a rotor, the rotor comprises the rotor punching sheet, the rotating direction of the rotor is a first circumference, the stator comprises a stator yoke part and a plurality of stator tooth parts arranged on the stator yoke part, the stator tooth parts are provided with tooth surfaces opposite to the outer circumference of the rotor punching sheet, when the tooth surfaces are arc surfaces around the rotating axis of the rotor, an air gap is arranged between the outer circumference of the rotor punching sheet and the tooth surfaces of the stator, and in the first circumference, the air gap is gradually expanded, so that the low-order radial electromagnetic force of the motor can be greatly improved, vibration and noise generated during the operation of the motor are reduced, in addition, the harmonic content of an air gap magnetic field is improved, the iron loss of the motor is reduced, and the energy efficiency of the motor is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a rotor lamination according to an embodiment of the present invention mated with a stator;

FIG. 2 is an enlarged view of a portion of F in FIG. 1;

FIG. 3 is a radial force density versus histogram for a conventional motor and a motor in accordance with the present invention;

fig. 4 is a graph of vibration acceleration versus a bar graph of a conventional motor and a motor according to the present invention.

Reference numerals illustrate:

reference numerals	Name of the name	Reference numerals	Name of the name
				100	Rotor punching sheet	400	Circular arc line
211	q-axis	410	First arc end point
				220	A first axis	420	Second arc end point
230	Center of rotation	430	A first arc section
				240	Mounting hole	440	Second arc section
300	Edge of punching sheet	510	First region
				310	Midpoint (midpoint)	520	Second region
320	First end point	600	Stator
				330	Second end point	610	Stator yoke
340	First section	620	Stator tooth
				350	Second section	630	Stator groove

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that all directional indications (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship between the components, the movement condition, etc. in a specific posture, and if the specific posture is changed, the directional indication is changed accordingly.

In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly through intermediaries, or in abutment, or in communication between two elements or in interaction with each other, unless explicitly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.

At present, the motor includes stator and rotor, the rotor includes the rotor towards the piece, the rotor towards the piece has the peripheral, the peripheral is circular setting, the stator includes stator yoke portion, and locate a plurality of stator tooth portions of stator yoke portion, the stator tooth portion has the tooth face opposite with the peripheral of rotor towards the piece, the tooth face is the circular arc face around the axis of rotation of rotor, the distance of the outer peripheral of rotor towards the circular arc face is equal, this makes the motor can produce great vibration when running, thereby produce great noise. The reason for such design by those skilled in the art is that the running conditions of the motor in two rotation directions are considered, and the rotor punching sheet adopts the structure, so that the harmonic magnetic fields of the motor in the two conditions cannot be greatly different, and particularly large vibration and noise cannot be generated in any one of the working conditions. However, in a compressor of a refrigeration device, most of motors rotate in a single phase, and the existing rotor punching sheets cannot weaken more radial force density of the motors and electromagnetic exciting force generated by an air gap. To this end, the present invention proposes a rotor lamination aimed at reducing vibrations and noise generated during the operation of the motor.

Referring to fig. 1 and 2, in an embodiment of the present invention, the rotor sheet 100 has an outer periphery, the outer periphery includes a plurality of sheet edges 300, two ends of the sheet edges 300 are respectively disposed on two adjacent q-axes 211 of the rotor sheet 100, and in a first circumferential direction of the outer periphery, a distance between the sheet edges 300 and a rotation center 230 of the rotor sheet 100 is in a decreasing trend. It should be noted that, the first circumferential direction is shown in the E direction in the drawing, and it is understood that the first circumferential direction may be clockwise, or counterclockwise, and E in the drawing illustrates the present embodiment by taking the counterclockwise direction as an example. In this way, when the motor includes the stator 600 and the rotor, the rotor includes the rotor punching sheet 100, the rotation direction of the rotor is the first circumference, the stator 600 includes the stator yoke 610, and a plurality of stator teeth 620 provided on the stator yoke 610, the stator teeth 620 have tooth surfaces opposite to the outer circumference of the rotor punching sheet 100, when the tooth surfaces are arc surfaces around the rotation axis of the rotor, an air gap is provided between the outer circumference of the rotor punching sheet 100 and the tooth surfaces of the stator 600, and in the first circumference, the air gap is gradually expanded, which greatly improves the low-order radial electromagnetic force of the motor, thereby reducing vibration and noise generated during the operation of the motor, in addition, improving the harmonic content of the air gap magnetic field, reducing the iron loss of the motor, and improving the energy efficiency of the motor.

Optionally, in an embodiment, the sheet edge 300 has a first end 320 and a second end 330, the center of rotation 230 is spaced from the first end 320 by a distance R1, the second end 330 is spaced from the second end 330 by a distance R2, and the center 310 of the sheet edge 300 is spaced from the center 310 by a distance R3, and the rotor sheet 100 is configured to be disposed in an inner bore of the stator 600, wherein the inner bore has a radius R1 < R3 < R2 < R. It will be appreciated that in the first direction, the second end 330 and the first end 320 are disposed in sequence, and the midpoint 310 of the die edge 300 is located between the second end 330 and the first end 320, with the internal bore being defined by the tooth surfaces of the plurality of stator teeth 620. In addition, the difference between R3 and R1 and the difference between R2 and R3 are identical. Therefore, the low-order radial electromagnetic force of the motor can be greatly improved, the noise generated by the motor is reduced, the harmonic content of an air gap magnetic field is improved, the iron loss of the motor is reduced, and the energy efficiency of the motor is improved. Note that, the difference between R3 and R1 and the difference between R2 and R3 are identical, meaning that the difference between R3 and R1 and the difference between R2 and R3 are close to each other, and that R3-r1=r2-R3 is not lost. Further, in one embodiment, r1=27.85 mm, r3=28.1 mm, r2=28.35 mm, r3—r1=r2—r3=0.25 mm. However, the present design is not limited thereto, and in other embodiments, the parameters of R1, R2, and R3 may be other, and will not be described herein in detail.

Optionally, the sheet edge 300 has a first end 320 and a second end 330, the distance between the rotation center 230 and the first end 320 is R1, the distance between the rotation center and the second end 330 is R2, the distance between the rotation center and the midpoint 310 of the sheet edge 300 is R3, and the rotor sheet 100 is configured to be disposed in an inner hole of the stator 600, where the radius of the inner hole is R, and R1 < R3 < R2 < R. It will be appreciated that in the first direction, the second end 330 and the first end 320 are disposed in sequence, and the midpoint 310 of the die edge 300 is located between the second end 330 and the first end 320, with the internal bore being defined by the tooth surfaces of the plurality of stator teeth 620. Furthermore, R2-R1 < 2 (R-R3), i.e. R2-R1 < 2R3. Therefore, the low-order radial electromagnetic force of the motor can be greatly improved, the noise generated by the motor is reduced, the harmonic content of an air gap magnetic field is improved, the iron loss of the motor is reduced, and the energy efficiency of the motor is improved. Further, in one embodiment, without loss of generality, r1=27.85 mm, r3=28.1 mm, r2=28.35 mm, r=28.6 mm, r3—r1=r2—r3=0.25 mm, r2—r1=0.5 mm. R-r3=0.5 mm. However, the present design is not limited thereto, and in other embodiments, the parameters of R, R, R2, and R3 may be other, and will not be described herein.

Optionally, in an embodiment, the sheet edge 300 has a first end 320 and a second end 330, the center of rotation 230 is spaced from the first end 320 by a distance R1, the second end 330 is spaced from the second end 330 by a distance R2, and the center 310 of the sheet edge 300 is spaced from the center 310 by a distance R3, and the rotor sheet 100 is configured to be disposed in an inner bore of the stator 600, wherein the inner bore has a radius R1 < R3 < R2 < R. It will be appreciated that in the first direction, the second end 330 and the first end 320 are disposed in sequence, and the midpoint 310 of the die edge 300 is located between the second end 330 and the first end 320, with the internal bore being defined by the tooth surfaces of the plurality of stator teeth 620. In addition, R-R3 is more than or equal to 0.4mm and less than or equal to 0.7mm. Therefore, the low-order radial electromagnetic force of the motor can be greatly improved, the noise generated by the motor is reduced, the harmonic content of an air gap magnetic field is improved, the iron loss of the motor is reduced, and the energy efficiency of the motor is improved. Further, in one embodiment, r3=28.1 mm, r=28.6 mm, R-r3=0.5 mm. However, the present design is not limited thereto, and in other embodiments, the parameters of R and R3 may be other, and will not be described herein in detail.

Optionally, in an embodiment, the area of the area surrounded by the circle with the center of rotation 230 as the center and R3 as the radius is identical to the area of the area surrounded by the outer periphery of the rotor punching sheet 100.

Specifically, the circular arc has a circular arc line 400, the circular arc line 400 has a first circular arc end point 410 and a second circular arc end point 420 respectively disposed on two adjacent q-axes 211, the second circular arc end point 420 and the first circular arc end point 410 are sequentially disposed in a first circumferential direction, the circular arc has a first arc segment 430 from the midpoint 310 of the sheet edge 300 to the first circular arc end point 410, and a second arc segment 440 from the midpoint 310 of the sheet edge 300 to the second circular arc end point 420, the sheet edge 300 includes a first segment 340 having the first end point 320 to the midpoint 310 of the sheet edge 300, and a second segment 350 having the second end point 330 to the midpoint 310 of the sheet edge 300, it is noted that the two adjacent q-axes 211 are symmetrical about the first axis 220, the first axis 220 forms a common region 510 through the midpoint 310 of the sheet edge 300, the first segment 340, and the first arc segment 410 to the first end point 320, and the second segment 520 to the common region 510. The area of the area surrounded by the circle with the rotation center 230 as the center and the radius R3 is identical to the area of the area surrounded by the outer periphery of the rotor punching sheet 100. Meaning that the area of the first region 510 is identical to the area of the second region 520. For convenience of description, the area of the first region 510 is defined herein as S1, and the area of the second region 520 is defined herein as S2. S1 and S2 agree to mean that the value of S1 and the value of S2 are relatively close, and s1=s2 without loss of generality. Further, in one embodiment, s1=s2=1.8 mm ² . However, the present design is not limited thereto, and S1 and S2 are shown in other embodimentsThe values of (2) may be other, and are not described in detail herein.

In the prior art, the outer periphery of the rotor punching sheet 100 is circularly arranged, and the air gap area of the prior art is equivalent to that of the scheme, so that the fundamental magnetic density of the motor as the scheme after improvement is not affected basically, and the output torque of the motor is not affected. Under the condition that the output torque is not influenced, the scheme also realizes the substantial improvement of the low-order radial electromagnetic force of the motor, reduces the noise generated by the motor, improves the harmonic content of the air gap magnetic field, reduces the iron loss of the motor and improves the energy efficiency of the motor.

There are a variety of configurations for the die edge 300, and alternatively, in one embodiment, the die edge 300 is disposed in an arc. In this way, the degree of undulation of the sheet edge 300 is continuous, and the change of the sheet edge 300 is a regular circular arc change, so that the air gap is ensured to be gradually reduced in the rotation direction of the rotor sheet 100, and radial electromagnetic waves are reduced. However, the present design is not limited thereto, and in other embodiments, the sheet edge 300 includes multiple straight line segments and/or multiple arc segments. Specifically, the sheet edge 300 may be formed by connecting a plurality of straight line segments, may be formed by connecting a plurality of arc line segments, or may be formed by connecting a plurality of straight line segments and a plurality of arc line segments. The punching edge 300 is formed by connecting a plurality of straight line segments and a plurality of arc segments, and can be formed by alternately connecting the straight line segments and the arc segments, or can be formed by connecting an integral body formed by connecting the plurality of straight line segments with one end of an integral body formed by connecting the plurality of arc segments, or can be in other structural forms, and is not limited herein.

The rotor punching sheet 100 is provided with mounting holes 240 through which the permanent magnets pass, and the mounting holes 240 on each rotor punching sheet 100 can be correspondingly communicated to form mounting grooves for mounting and placing the permanent magnets when being overlapped to form a rotor. The permanent magnets can be ferrite permanent magnets or alloy permanent magnets, and it is understood that the shape of the permanent magnets needs to be matched with the shape of the mounting groove, and the permanent magnets arranged in one mounting groove are one pole. However, there are various shapes of the mounting holes 240, and alternatively, in one embodiment, the rotor sheet 100 is provided with the mounting holes 240 for mounting the permanent magnets, and the mounting holes 240 are arranged in a V-shape, a U-shape, a W-shape, an I-shape, or a straight shape. Here, the shape of the mounting hole 240 is a shape of a projection along the extending direction of the rotation axis of the rotor blade 100. However, the present design is not limited thereto, and in other embodiments, the mounting hole 240 may have other shapes, which are not limited thereto.

The present invention also proposes a rotor, which includes the rotor punching sheet 100 described above, and the specific structure of the rotor punching sheet 100 refers to the foregoing embodiments, and since the rotor adopts all the technical solutions of all the foregoing embodiments, at least has all the beneficial effects brought by the technical solutions of the foregoing embodiments, which are not described herein in detail. It will be appreciated that the rotor includes a plurality of rotor sheets 100, which may be formed from a stack of rotor sheets 100 axially.

The invention also provides a motor, which comprises a stator 600 and the rotor, wherein the specific structure of the rotor refers to the above embodiment, and because the motor adopts all the technical schemes of all the embodiments, the motor has at least all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted herein. The stator 600 may be formed by axially laminating a plurality of stator 600 laminations. The rotor is rotatably provided to the stator 600.

Optionally, in an embodiment, the number of stator slots 630 of the stator 600 is Q, the pole pair number of the rotor is P, and the number of phases of the motor is m, Q/2Pm < 1. Therefore, the low-order radial electromagnetic force of the motor is greatly improved, the noise generated by the motor is reduced, the harmonic content of an air gap magnetic field is improved, the iron loss of the motor is reduced, and the energy efficiency of the motor is improved.

Further, as shown in fig. 3 and 4, fig. 3 is a radial force density versus bar graph of a conventional motor and a motor according to the present invention, and fig. 4 is a vibration acceleration versus bar graph of a conventional motor and a motor according to the present invention. The conventional motor and the motor proposed by the present invention are both 9 slots 6 poles, the stator tooth 620 of the stator 600 has a tooth surface opposite to the outer circumference of the rotor sheet 100, the tooth surface is an arc surface around the rotation axis of the rotor, the conventional motor is different from the motor proposed by the present invention in that the sheet edge 300 is a conventional rotor, the distance from each point of the sheet edge 300 of the conventional rotor to the rotation center 230 is equal, the rotor of the motor proposed by the present invention is an eccentric rotor, the distance from the sheet edge 300 of the eccentric rotor to the rotation center 230 is gradually reduced in the rotation direction of the rotor sheet 100, the difference between R3 and R1 and the difference between R2 and R3 are identical, R2-R1 < 2 (R-R3), R-R3 is 0.4mm < 0.7mm, S1 and S2 are identical, and the sheet edge 300 is arranged in an arc. It can be seen that the data of the motor proposed by the invention is better, both in radial force density and in vibration acceleration. In FIG. 3, the radial force density of the conventional motor is 46500N/m2, while the radial force density of the motor of the present invention is 23000N/m2. In FIG. 4, the radial force density of the conventional motor is 5.7m/s2, while the radial force density of the motor of the present invention is 3.5m/s2.

It can be understood that in the motor of the compressor, the noise of 2 times of electric frequency is most prominent, the electromagnetic force of 2 times of electric frequency is mainly generated by the action of fundamental wave magnetic density and 2 times of harmonic magnetic density, the fundamental wave magnetic density is kept unchanged, and the reduction of 2 times of harmonic magnetic density is an important direction for improving noise.

Taking 9 slots 6 as an example, the main sources of the 2 nd harmonic magnetic density B are respectively: magnetic flux density B1 formed by the action of fundamental magnetomotive force and first-order harmonic magnetic flux guide of stator 600; magnetic density B2 formed by the action of stator 600-2 subharmonic magnetomotive force and main magnetic permeability; magnetic density B3 formed by the action of stator 600-5 order harmonic magnetomotive force and first order harmonic magnetic permeability; and the magnetic flux density B4 is formed by the action of the fundamental wave magnetomotive force and the first-order harmonic magnetic flux.

Through the rotor punching sheet 100 of the scheme, the amplitude of the synthesized 2 nd harmonic magnetic flux density B is greatly weakened through phase adjustment under the condition of keeping the fundamental magnetic flux density unchanged by introducing the additional phase of the first-order harmonic magnetic flux density, and then the 2-time electric frequency radial electromagnetic force is greatly reduced. The purpose of reducing motor noise is achieved.

The invention also provides a compressor which comprises the motor, and the specific structure of the motor refers to the embodiment, and because the compressor adopts all the technical schemes of all the embodiments, the compressor at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted herein.

The invention also provides a refrigeration device, which comprises the compressor, and the specific structure of the compressor refers to the embodiment, and because the refrigeration device adopts all the technical schemes of all the embodiments, the refrigeration device at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted herein. The refrigeration device may be, but is not limited to, a refrigerator or an air conditioner, etc.

The foregoing description is only of the optional embodiments of the present invention, and is not intended to limit the scope of the invention, and all the equivalent structural changes made by the description of the present invention and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the invention.

Claims (10)

1. The rotor punching sheet is characterized by comprising an outer periphery, wherein the outer periphery comprises a plurality of punching sheet edges, two ends of each punching sheet edge are respectively arranged on two adjacent q axes of the rotor punching sheet, and the distance between each punching sheet edge and the rotation center of the rotor punching sheet is in a reduced change trend in the first periphery of the outer periphery.

2. The rotor punching sheet according to claim 1, wherein the sheet edge has a first end point and a second end point, the distance between the rotation center and the first end point is R1, the distance between the rotation center and the second end point is R2, the distance between the rotation center and the midpoint of the sheet edge is R3, the rotor punching sheet is used for being arranged in an inner hole of a stator, the radius of the inner hole is R, and R1 is less than R3 and less than R2 is less than R;

the difference between R3 and R1 is consistent with the difference between R2 and R3; and/or R2-R1 < 2 (R-R3); and/or R-R3 is more than or equal to 0.4mm and less than or equal to 0.7mm.

3. The rotor punching sheet according to claim 2, wherein an area of a region surrounded by a circle having the rotation center as a center and R3 as a radius coincides with an area of a region surrounded by an outer periphery of the rotor punching sheet.

4. The rotor punching of claim 1, wherein the punching edges are arranged in an arc;

or, the punching sheet edge comprises a plurality of straight line segments and/or a plurality of arc segments.

5. The rotor punching sheet according to claim 1, wherein the rotor punching sheet is provided with mounting holes for mounting the permanent magnets, and the mounting holes are arranged in a V shape, a U shape, a W shape, an I shape, or a straight shape.

6. A rotor comprising a plurality of rotor blades according to any one of claims 1 to 5.

7. An electric machine, comprising:

a stator; and

the rotor of claim 6 rotatably disposed in the stator.

8. The motor of claim 7 wherein the number of stator slots of the stator is Q, the pole pair number of the rotor is P, and the number of phases of the motor is m, Q/2Pm < 1.

9. A compressor comprising the motor of claim 7 or 8.

10. A refrigeration apparatus comprising the compressor of claim 9.