Rotor core, motor and compressor

Abstract

The invention provides a rotor iron core, a motor and a compressor, the rotor iron core comprises an iron core body, the iron core body comprises a plurality of magnetic poles, each magnetic pole is internally provided with a first magnetic isolation hole group and a second magnetic isolation hole group, the first magnetic isolation hole group is located between the second magnetic isolation hole group and the outer edge of the iron core body, and the second magnetic isolation hole group is located between the second magnetic isolation hole group and the outer edge of the iron core body. The first magnetic isolation hole group comprises Z first magnetic isolation holes extending in the axial direction of the iron core body, the first magnetic isolation holes are distributed at intervals in the circumferential direction of the iron core body, the second magnetic isolation hole group comprises Z-1 second magnetic isolation holes extending in the axial direction of the iron core body, and the second magnetic isolation holes are distributed at intervals in the circumferential direction of the iron core body; the position of each second magnetic isolation hole corresponds to the area between every two adjacent first magnetic isolation holes. According to the invention, the two magnetic isolation hole groups optimize the magnetic circuit, reduce the harmonic amplitude of the back electromotive force and improve the sine degree of the waveform of the back electromotive force, so that the torque ripple of the motor during load operation is reduced, and the operation noise of the motor is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric machines, and particularly relates to a rotor core, an electric machine and a compressor. BACKGROUND

[0002] The noise of the existing variable frequency compressor mainly comes from the permanent magnet synchronous motor, and the motor noise is closely related to the torque ripple. The torque ripple can cause the vibration of the mechanical parts inside the motor, thereby generating noise. In addition, the back EMF harmonic can also cause the distortion of the motor current waveform, further causing the torque ripple, and thereby increasing the noise. SUMMARY

[0003] Therefore, the application provides a rotor core, which can solve the technical problem that the back EMF harmonic can cause the distortion of the motor current waveform, further cause the torque ripple, and thereby increase the noise.

[0004] In order to solve the above problems, the application provides a rotor core, which comprises a core body, the core body comprises a plurality of magnetic poles, each of the magnetic poles is configured with a first magnetic isolation hole group and a second magnetic isolation hole group, the first magnetic isolation hole group is between the second magnetic isolation hole group and the outer edge of the core body, the first magnetic isolation hole group comprises Z first magnetic isolation holes extending along the axial direction of the core body, and each of the first magnetic isolation holes is spaced apart along the circumferential direction of the core body, the second magnetic isolation hole group comprises Z-1 second magnetic isolation holes extending along the axial direction of the core body, and each of the second magnetic isolation holes is spaced apart along the circumferential direction of the core body, and the position of each of the second magnetic isolation holes corresponds to the area between each of the two adjacent first magnetic isolation holes; wherein Z is greater than or equal to 2.

[0005] In some embodiments, the plane in which any cross section of the core body is located is a projection plane, the vertical projection of the magnetic pole in the projection plane is a first pattern, the first pattern has a first symmetry axis, the first magnetic isolation hole group is symmetrical relative to the first symmetry axis, the projection of any first magnetic isolation hole at the two side edges of the first magnetic isolation hole group in the projection plane is a second pattern, the second pattern has a second symmetry axis, the projection of the core body in the projection plane is a third pattern, the third pattern has a center point O, the first symmetry axis and the second symmetry axis both pass through the center point O, the included angle between the first symmetry axis and the second symmetry axis is θ, 360° / np≤θ≤360° / Np; wherein n is the number 7 of the 7th harmonic, N is the number 5 of the 5th harmonic, and p is the pole number of the core body.

[0006] In some embodiments, the width of the first magnetic isolation hole is Q1, the width of the second magnetic isolation hole is Q2, a first magnetic isolation bridge is formed between the first magnetic isolation hole group and the second magnetic isolation hole group along the radial direction of the core body, the width of the first magnetic isolation bridge is Q3, a second magnetic isolation bridge is formed between the first magnetic isolation hole group and the outer edge of the core body, the maximum width of the second magnetic isolation bridge is Q4, Q1=Q2=Q3=Q4.

[0007] In some embodiments, a first magnetic isolation bridge is formed between the first magnetic isolation hole group and the second magnetic isolation hole group along the radial direction of the core body, the width of the first magnetic isolation bridge is Q3, 0.5mm≤Q3≤0.78mm; and / or, a second magnetic isolation bridge is formed between the first magnetic isolation hole group and the outer edge of the core body along the radial direction of the core body, the maximum width of the second magnetic isolation bridge is Q4, 0.5mm≤Q4≤0.78mm.

[0008] In some embodiments, the width of the first magnetic isolation hole is Q1, the length of the first magnetic isolation hole is L1, 1≤Q1 / L1≤4.5; and / or, the width of the second magnetic isolation hole is Q2, the length of the second magnetic isolation hole is L2, 1≤Q2 / L2≤4.5.

[0009] In some embodiments, two magnetic steel grooves are formed in each of the magnetic poles, a third magnetic isolation bridge is formed between the two magnetic steel grooves close to one end of the center of the core body, and the included angle between the two magnetic steel grooves is a, 90°≤a≤105°.

[0010] The application also provides an electric machine comprising the aforementioned rotor core.

[0011] In some embodiments, the outer diameter of the rotor core is R1, a stator core is arranged on the periphery of the rotor core, the inner diameter of the stator core is R2, the air gap between the rotor core and the stator core is σ, σ=R2-R1, 0.8mm<σ<1.7mm.

[0012] In some embodiments, a stator core is arranged on the periphery of the rotor core, the inner diameter of the stator core is R2, the outer diameter of the stator core is R3, 0.56<R2 / R3<0.59.

[0013] The application also provides a compressor comprising the aforementioned electric machine.

[0014] The rotor core, electric machine and compressor provided by the application have the following beneficial effects:

[0015] By constructing the first and second groups of flux barriers in each magnetic pole of the core body, and the position of each second flux barrier in the second group of flux barriers corresponding to the area between each adjacent two first flux barriers in the first group of flux barriers, the magnetic circuit is optimized, the amplitude of the counter electromotive force harmonic is reduced, the sine degree of the counter electromotive force waveform is improved, and the torque ripple of the motor during load operation is reduced, and the operation noise of the motor is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only exemplary, and other drawings can be derived from the provided drawings without creative labor for those skilled in the art.

[0017] Figure 1 a schematic view of the rotor core of the embodiment one of the present application;

[0018] Figure 2 a schematic view of the rotor core of the embodiment one of the present application;

[0019] Figure 3 a schematic view of the first flux barrier of the rotor core of the embodiment one of the present application;

[0020] Figure 4 a schematic view of the rotor core of the embodiment one of the present application;

[0021] Figure 5 a schematic view of the rotor core of the embodiment two of the present application;

[0022] Figure 6 a schematic view of the first flux barrier of the rotor core of the embodiment two of the present application;

[0023] Figure 7 a schematic view of the rotor core and the stator core of the motor of the embodiment of the present application;

[0024] Figure 8 a counter electromotive force harmonic comparison chart of the motor without the group of flux barriers in the prior art, the motor with only one group of flux barriers, and the motor of the embodiment of the present application.

[0025] The signs in the drawings represent:

[0026] 1, core body; 2, first flux barrier; 3, second flux barrier; 4, first symmetry axis; 5, second symmetry axis; 6, magnetic steel slot; 7, stator core. DETAILED DESCRIPTION

[0027] Clearly, the embodiments described are only a part of all the embodiments of the present application, rather than all the embodiments. The following description of at least one example embodiment is merely illustrative in nature and does not serve as any limitation to the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of the present application.

[0028] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, without the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation to the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer relative to the contour of each component.

[0029] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawings is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the example term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0030] In addition, it should be noted that the use of "first", "second" and the like to define parts has only the purpose of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, therefore it cannot be understood as a limitation to the scope of protection of the present application.

[0031] For reference Figures 1 to 8As shown, according to the embodiment of the present application, a rotor core is provided, comprising a core body 1, the core body 1 comprising a plurality of magnetic poles, each of the magnetic poles being configured with a first group of magnetic isolation holes and a second group of magnetic isolation holes, the first group of magnetic isolation holes being between the second group of magnetic isolation holes and an outer edge of the core body 1, the first group of magnetic isolation holes comprising Z first magnetic isolation holes 2 extending along an axial direction of the core body 1, and each of the first magnetic isolation holes 2 being spaced apart along a circumferential direction of the core body 1, the second group of magnetic isolation holes comprising Z-1 second magnetic isolation holes 3 extending along the axial direction of the core body 1, and each of the second magnetic isolation holes 3 being spaced apart along the circumferential direction of the core body 1, and a position of each of the second magnetic isolation holes 3 corresponding to a region between each of two adjacent first magnetic isolation holes 2, respectively; wherein Z≥2.

[0032] In the technical solution, by configuring the first group of magnetic isolation holes and the second group of magnetic isolation holes in each of the magnetic poles of the core body 1, and by making the positions of the second magnetic isolation holes 3 in the second group of magnetic isolation holes correspond to the regions between each of two adjacent first magnetic isolation holes 2 in the first group of magnetic isolation holes, respectively, the magnetic circuit is optimized, the back EMF harmonic amplitude is reduced, the sine degree of the back EMF waveform is improved, and thus the torque ripple of the motor during load operation is reduced, and the operation noise of the motor is reduced.

[0033] Referring to Figure 2 As shown, a plane in which any cross section of the core body 1 is located is a projection plane, a vertical projection of the magnetic pole in the projection plane is a first figure, the first figure has a first symmetry axis 4, the first group of magnetic isolation holes is symmetrical with respect to the first symmetry axis 4, a projection of any first magnetic isolation hole 2 at the two side edges of the first group of magnetic isolation holes in the projection plane is a second figure, the second figure has a second symmetry axis 5, a projection of the core body 1 in the projection plane is a third figure, the third figure has a center point O, the first symmetry axis 4 and the second symmetry axis 5 both pass through the center point O, an included angle formed between the first symmetry axis 4 and the second symmetry axis 5 is θ, 360° / np≤θ≤360° / Np; wherein n is the number 7 of the 7th harmonic, N is the number 5 of the 5th harmonic, and p is the pole number of the core body 1.

[0034] In the present embodiment, as Figure 8 shown, the back EMF 5th and 7th harmonic amplitudes are large, and the generated noise is large, and when the included angle θ satisfies 360° / np≤θ≤360° / Np, the back EMF 5th and 7th harmonic amplitudes of the motor can be reduced to a greater extent. It can be understood that in the case where the first group of magnetic isolation holes is symmetrical with respect to the first symmetry axis 4, the second group of magnetic isolation holes is also symmetrical with respect to the first symmetry axis 4.

[0035] Referring to Figure 2 , Figure 3 , Figure 5 and Figure 6As shown in the drawings, the second figure is a hexagon; or the second figure has a first straight side, a first semicircular arc, a second straight side, and a second semicircular arc, two ends of the first straight side are connected to a first end of the first semicircular arc and a first end of the second semicircular arc respectively, two ends of the second straight side are connected to a second end of the first semicircular arc and a second end of the second semicircular arc respectively, and the first straight side is parallel to the second straight side.

[0036] In the technical solution, the second figure represents the cross-sectional shape of all the first magnetic isolation holes 2. When the second figure is a hexagon as shown in the drawings, or a straight bar with two semicircular arcs as shown in the drawings, it is helpful to divide the magnetic flux path into multiple smaller areas. Smaller magnetic flux paths can reduce the generation of eddy currents, thereby improving the efficiency of the motor. At the same time, it can also provide a more uniform magnetic field distribution and reduce the noise of the motor. In addition, the second figure can also be an elliptical shape, a prismatic shape, etc. Figure 6 Figure 3 In the technical solution, the second figure represents the cross-sectional shape of all the first magnetic isolation holes 2. When the second figure is a hexagon as shown in the drawings, or a straight bar with two semicircular arcs as shown in the drawings, it is helpful to divide the magnetic flux path into multiple smaller areas. Smaller magnetic flux paths can reduce the generation of eddy currents, thereby improving the efficiency of the motor. At the same time, it can also provide a more uniform magnetic field distribution and reduce the noise of the motor. In addition, the second figure can also be an elliptical shape, a prismatic shape, etc.

[0037] As shown in the drawings, Figure 2 , Figure 3 , Figure 5 and Figure 6 , the vertical projection of the second magnetic isolation hole 3 in the projection plane is a fourth figure, and the fourth figure is a hexagon. Or the fourth figure has a third straight side, a third semicircular arc, a fourth straight side, and a fourth semicircular arc, two ends of the third straight side are connected to a first end of the third semicircular arc and a first end of the fourth semicircular arc respectively, two ends of the fourth straight side are connected to a second end of the third semicircular arc and a second end of the fourth semicircular arc respectively, and the third straight side is parallel to the fourth straight side.

[0038] In this embodiment, the fourth figure represents the cross-sectional shape of all the second magnetic isolation holes 3. When the fourth figure is a hexagon as shown in the drawings, or a straight bar with two semicircular arcs as shown in the drawings, it is helpful to divide the magnetic flux path into multiple smaller areas. Smaller magnetic flux paths can reduce the generation of eddy currents, thereby improving the efficiency of the motor. At the same time, it can also provide a more uniform magnetic field distribution and reduce the noise of the motor. In addition, the fourth figure can also be an elliptical shape, a prismatic shape, etc. Figure 6 Figure 3 In the technical solution, the second figure represents the cross-sectional shape of all the first magnetic isolation holes 2. When the second figure is a hexagon as shown in the drawings, or a straight bar with two semicircular arcs as shown in the drawings, it is helpful to divide the magnetic flux path into multiple smaller areas. Smaller magnetic flux paths can reduce the generation of eddy currents, thereby improving the efficiency of the motor. At the same time, it can also provide a more uniform magnetic field distribution and reduce the noise of the motor. In addition, the second figure can also be an elliptical shape, a prismatic shape, etc.

[0039] As shown in the drawings, Figure 2 , the width of the first magnetic isolation hole 2 is Q1, the width of the second magnetic isolation hole 3 is Q2, along the radial direction of the core body 1, the first magnetic isolation hole group and the second magnetic isolation hole group form a first magnetic isolation bridge, the width of the first magnetic isolation bridge is Q3, the first magnetic isolation hole group and the outer edge of the core body 1 form a second magnetic isolation bridge, the maximum width of the second magnetic isolation bridge is Q4, Q1=Q2=Q3=Q4.

[0040] ​​In the technical scheme, when Q1=Q2=Q3=Q4, the rotor structure is symmetrical, the magnetic field distribution is relatively uniform, the total harmonic distortion rate can be reduced, the back electromotive force waveform is closer to a sine, and the noise of the motor is reduced.

[0041] As a specific embodiment, 0.5mm≤Q3≤0.78mm; and / or, 0.5mm≤Q4≤0.78mm.

[0042] In the embodiment, from the overall strength of the rotor core, the too-narrow magnetic isolation bridge can cause small stress and be prone to fracture; from the cost and performance, the too-wide magnetic isolation bridge can cause increased magnetic leakage and reduced reluctance torque utilization. Through repeated demonstration, when 0.5mm≤Q3≤0.78mm; and / or, 0.5mm≤Q4≤0.78mm, the reduction degree of the back electromotive force harmonic is better and the overall strength of the rotor core can be considered.

[0043] Referring to Figure 2 As shown in the figure, the width of the first magnetic isolation hole 2 is Q1, the length of the first magnetic isolation hole 2 is L1, 1≤Q1 / L1≤4.5; and / or, the width of the second magnetic isolation hole 3 is Q2, the length of the second magnetic isolation hole 3 is L2, 1≤Q2 / L2≤4.5.

[0044] In the technical scheme, through repeated demonstration, when 1≤Q1 / L1≤4.5; and / or, 1≤Q2 / L2≤4.5, the electromagnetic noise and vibration of the motor during operation can be effectively weakened, and the running stability and comfort of the motor are improved. When the first magnetic isolation hole 2 and the second magnetic isolation hole 3 are in the shape as shown in the figure, L1 refers to the length of the upper base or the lower base of the first magnetic isolation hole 2; and L2 refers to the length of the upper base or the lower base of the second magnetic isolation hole 3. Figure 3 Or Figure 6 As shown in the figure, the width of the first magnetic isolation hole 2 is Q1, the length of the first magnetic isolation hole 2 is L1, 1≤Q1 / L1≤4.5; and / or, the width of the second magnetic isolation hole 3 is Q2, the length of the second magnetic isolation hole 3 is L2, 1≤Q2 / L2≤4.5.

[0045] Referring to Figure 1 As shown in the figure, two magnetic steel grooves 6 are arranged in each magnetic pole, a third magnetic isolation bridge is formed between one end of the two magnetic steel grooves 6 close to the center of the core body 1, and the included angle a between the two magnetic steel grooves 6 is 90°≤a≤105°.

[0046] The application further provides a motor comprising the rotor core.

[0047] Referring to Figure 7 As shown in the figure, the outer diameter of the rotor core is R1, a stator core 7 is arranged on the periphery of the rotor core, the inner diameter of the stator core 7 is R2, the air gap between the rotor core and the stator core 7 is sigma, sigma=R2-R1, and 0.8mm<sigma<1.7mm.

[0048] In the technical solution, the air gap length σ directly affects the magnetic field distribution and inductance parameters, a larger air gap can increase the split ratio and improve the reluctance torque, but will increase the copper loss and make the permanent magnet utilization rate decline; a smaller air gap can improve the air gap magnetic field strength and enhance the permanent magnet torque, but will increase the magnetic field harmonics, resulting in the increase of iron loss and torque ripple. After repeated demonstration, when the air gap length is in the range of 0.8mm to 1.7mm, the split ratio and the magnetic field utilization rate can be balanced, so that the reluctance torque can be improved and excessive loss can be avoided.

[0049] Referring to Figure 7 As shown in the figure, the outer diameter of the stator core 7 is R3, and 0.56

[0050] In the embodiment, after repeated demonstration, when the ratio of the inner and outer diameters of the stator core 7 is in the range of 0.56 to 0.59, the stator tooth part is wider, the permanent magnet magnetic flux path is smoother, which is conducive to enhancing the q-axis reluctance and reducing the d-axis reluctance, thereby improving the reluctance torque, while avoiding magnetic circuit saturation and improving the motor efficiency.

[0051] The application also provides a compressor comprising the motor.

[0052] It is easy for those skilled in the art to understand that the advantageous technical features of the above-mentioned modes can be freely combined and superimposed without conflict.

[0053] The above is only a preferred embodiment of the application and is not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application. The above is only a preferred embodiment of the application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the application, a number of improvements and modifications can be made, and these improvements and modifications should be regarded as the protection scope of the application.

Claims

1. A rotor core, characterized in that, The system includes an iron core body (1), which includes multiple magnetic poles. Each magnetic pole has a first magnetic isolation hole group and a second magnetic isolation hole group. The first magnetic isolation hole group is located between the second magnetic isolation hole group and the outer edge of the iron core body (1). The first magnetic isolation hole group includes Z first magnetic isolation holes (2) extending along the axial direction of the iron core body (1), and each first magnetic isolation hole (2) is spaced apart along the circumference of the iron core body (1). The second magnetic isolation hole group includes Z-1 second magnetic isolation holes (3) extending along the axial direction of the iron core body (1), and each second magnetic isolation hole (3) is spaced apart along the circumference of the iron core body (1). The location of each second magnetic isolation hole (3) corresponds to the area between each two adjacent first magnetic isolation holes (2); wherein, Z≥2.

2. The rotor core according to claim 1, characterized in that, The plane containing any cross-section of the core body (1) is the projection plane. The vertical projection of the magnetic pole in the projection plane is a first figure. The first figure has a first axis of symmetry (4). The first magnetic isolation hole group is symmetrical with respect to the first axis of symmetry (4). The projection of any of the first magnetic isolation holes (2) located on both sides of the first magnetic isolation hole group in the projection plane is a second figure. The second figure has a second axis of symmetry (5). The projection of the core body (1) in the projection plane is a third figure. The third figure has a center point O. The first axis of symmetry (4) and the second axis of symmetry (5) both pass through the center point O. The included angle formed between the first axis of symmetry (4) and the second axis of symmetry (5) is θ. 360° / np≤θ≤360° / Np; where n is the number 7 of the 7th harmonic, N is the number 5 of the 5th harmonic, and p is the number of poles of the core body (1).

3. The rotor core according to claim 1, characterized in that, The width of the first magnetic isolation hole (2) is Q1, the width of the second magnetic isolation hole (3) is Q2, a first magnetic isolation bridge is formed between the first magnetic isolation hole group and the second magnetic isolation hole group along the radial direction of the iron core body (1), the width of the first magnetic isolation bridge is Q3, a second magnetic isolation bridge is formed between the first magnetic isolation hole group and the outer edge of the iron core body (1), the maximum width of the second magnetic isolation bridge is Q4, Q1=Q2=Q3=Q4.

4. The rotor core according to claim 1, characterized in that, Along the radial direction of the core body (1), a first magnetic isolation bridge is formed between the first magnetic isolation hole group and the second magnetic isolation hole group, the width of the first magnetic isolation bridge being Q3, 0.5mm≤Q3≤0.78mm; and / or, along the radial direction of the core body (1), a second magnetic isolation bridge is formed between the first magnetic isolation hole group and the outer edge of the core body (1), the maximum width of the second magnetic isolation bridge being Q4, 0.5mm≤Q4≤0.78mm.

5. The rotor core according to claim 1, characterized in that, The width of the first magnetic isolation hole (2) is Q1, the length of the first magnetic isolation hole (2) is L1, 1≤Q1 / L1≤4.5; and / or, the width of the second magnetic isolation hole (3) is Q2, the length of the second magnetic isolation hole (3) is L2, 1≤Q2 / L2≤4.

5.

6. The rotor core according to claim 1, characterized in that, Each of the magnetic poles is constructed with two magnetic steel slots (6). A third magnetic isolation bridge is formed between the two magnetic steel slots (6) near the center of the iron core body (1). The included angle between the two magnetic steel slots (6) is α, where 90°≤α≤105°.

7. An electric motor, characterized in that, Includes the rotor core as described in any one of claims 1 to 6.

8. The motor according to claim 7, characterized in that, The outer diameter of the rotor core is R1, and a stator core (7) is provided around the rotor core. The inner diameter of the stator core (7) is R2, and the air gap between the rotor core and the stator core (7) is σ, where σ = R2 - R1, 0.8 mm < σ < 1.7 mm.

9. The motor according to claim 7, characterized in that, The rotor core is surrounded by a stator core (7), the inner diameter of the stator core (7) is R2, the outer diameter of the stator core (7) is R3, and 0.56 < R2 / R3 < 0.

59.

10. A compressor, characterized in that it includes the motor as described in claims 7 to 9.

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