Rotor structure, electric machine and compressor

Abstract

The main purpose of the present application is to provide a rotor structure, a motor and a compressor, wherein the rotor structure comprises a rotor core and a plurality of permanent magnets arranged on the rotor core to form a plurality of magnetic poles on the rotor core, the plurality of magnetic poles comprising a plurality of N poles and a plurality of S poles arranged alternately along the circumference of the rotor core; a plurality of magnetic isolation holes are arranged on at least one magnetic pole of the rotor core, and the plurality of magnetic isolation holes comprise a first magnetic isolation hole and a second magnetic isolation hole arranged at intervals in a direction away from the axis of the rotor core; a plane perpendicular to the axis of the rotor core is a predetermined plane, and the projection of the first magnetic isolation hole on the predetermined plane and the projection of the second magnetic isolation hole on the predetermined plane are both strips and are arranged in intersecting directions. Through the above arrangement of the present application, the problem of large vibration noise of the motor in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and more specifically, to a rotor structure, an electric motor, and a compressor. Background Technology

[0002] In recent years, with the development of permanent magnet material manufacturing technology and the rapid decline in cost, the high performance and low price of permanent magnet materials have greatly promoted the development of permanent magnet motor technology. The abundance of permanent magnet material resources has also facilitated the research and development of permanent magnet motor technology.

[0003] Permanent magnet motors generate their main magnetic field using permanent magnets. Compared to ordinary induction motors, permanent magnet synchronous motors do not require reactive excitation current, and their rotor resistance loss is zero during synchronous operation. Therefore, they feature high power factor and high efficiency, and are often used to replace induction motors with lower power performance. Their economic and social benefits are significant, leading to their widespread application across various industries.

[0004] However, the permanent magnet material of permanent magnet synchronous motors has a fixed energy product for permanent magnets of a fixed grade and material, making it difficult to adjust the air gap magnetic field of the motor. At the same time, the tooth and cogging structure of the motor results in a large harmonic content of air gap magnetic flux density and back EMF, and a large peak value of electromagnetic force density, which leads to large torque pulsation and vibration noise of the motor. Summary of the Invention

[0005] The main objective of this invention is to provide a rotor structure, a motor, and a compressor to solve the problem of excessive vibration and noise in existing motors.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a rotor structure is provided, comprising a rotor core and a plurality of permanent magnets disposed on the rotor core to form a plurality of magnetic poles on the rotor core, the plurality of magnetic poles including a plurality of N poles and a plurality of S poles alternately arranged along the circumference of the rotor core; at least one magnetic pole of the rotor core is provided with a magnetic isolation hole group, the magnetic isolation hole group having a first magnetic isolation hole and a second magnetic isolation hole spaced apart along a direction away from the axis of the rotor core; with a plane perpendicular to the axis of the rotor core as a predetermined plane, the projections of the first magnetic isolation hole and the second magnetic isolation hole on the predetermined plane are both strip-shaped and their extension directions are intersecting.

[0007] Furthermore, the projection of the first magnetic isolation hole onto the predetermined plane is perpendicular to the projection of the second magnetic isolation hole onto the predetermined plane.

[0008] Furthermore, the projection of the first magnetic isolation hole on the predetermined plane extends circumferentially along the rotor core or along a direction perpendicular to the center line of the corresponding magnetic pole; and / or the projection of the second magnetic isolation hole on the predetermined plane extends radially along the rotor core or along a direction parallel to the center line of the corresponding magnetic pole.

[0009] Furthermore, the first circumferential surface is the circumferential surface with the rotor core axis as the center, located on the side of the first magnetic isolation hole furthest from the rotor core axis; the second circumferential surface is the circumferential surface with the rotor core axis as the center, located on the side of the first magnetic isolation hole closest to the rotor core axis; the end of the second magnetic isolation hole near the rotor core axis is located between the first and second circumferential surfaces; or the end of the second magnetic isolation hole near the rotor core axis is located on the first circumferential surface or outside the first circumferential surface; or the end of the second magnetic isolation hole near the rotor core axis is located on the second circumferential surface or inside the second circumferential surface.

[0010] Furthermore, the first circumferential surface, which is located on the side of the first magnetic isolation hole that is furthest from the axis of the rotor core, is a circular surface with the axis of the rotor core as its center. The radius of the first circumferential surface is A, and the radius of the rotor core is B; where 0.87≥A / B≥0.5.

[0011] Furthermore, the circumferential surface containing the side of the first magnetic isolation hole closest to the axis of the rotor core, with the axis of the rotor core as the central axis, is the second circumferential surface. The radius of the second circumferential surface is C, and the radius of the rotor core is B; where 0.7≥C / B≥0.4.

[0012] Furthermore, the projection of the first magnetic isolation hole onto the predetermined plane is a first rectangular structure, the length of the first rectangular structure is D, and the width of the first rectangular structure is E; wherein, 5.3≥D / E≥2.

[0013] Furthermore, the projection of the second magnetic isolation hole onto the predetermined plane is a second rectangular structure, the length of the second rectangular structure is F, and the width of the second rectangular structure is G; wherein, 7≥F / G≥3.

[0014] Furthermore, the length of the projection of the first magnetic isolation hole onto the predetermined plane is D, the distance between the point of the projection of the first magnetic isolation hole onto the predetermined plane closest to the permanent magnet and the permanent magnet is H, and the minimum distance between the first magnetic isolation hole and the second magnetic isolation hole is J; where 1.8≥(H+J) / D≥0.5.

[0015] Furthermore, each magnetic pole is provided with multiple sets of magnetic isolation holes, which are arranged in pairs, with the two sets of magnetic isolation holes located on both sides of the magnetic pole centerline.

[0016] Furthermore, the first magnetic isolation hole of the two paired magnetic isolation hole groups is symmetrically arranged with respect to the center line of the magnetic pole; the second magnetic isolation hole of the two paired magnetic isolation hole groups is symmetrically arranged with respect to the center line of the magnetic pole.

[0017] Furthermore, the projection of the first magnetic isolation hole onto the predetermined plane extends perpendicularly to the center line of the magnetic pole. The center line of the projection of the first magnetic isolation hole onto the predetermined plane along its extension direction is the first center line, and the center line of the projection of the second magnetic isolation hole onto the predetermined plane along its extension direction is the second center line. The angle between the first center line and the second center line is K, and the angle between the permanent magnets located on both sides of the corresponding magnetic pole is L. Wherein, 1.6≥K / L≥0.4.

[0018] Furthermore, the projection of the second magnetic isolation hole onto the predetermined plane is parallel to the center line of the magnetic pole, the center line of the projection of the first magnetic isolation hole onto the predetermined plane along its extension direction is the first center line, and the center line of the projection of the second magnetic isolation hole onto the predetermined plane along its extension direction is the second center line; the angle between the first center line and the second center line is M, and the angle between the permanent magnets located on both sides of the corresponding magnetic pole is L; wherein, 2.4≥M / L≥0.5.

[0019] Furthermore, the first magnetic isolation hole is arranged parallel to the permanent magnet on the side wall near the permanent magnet and at a distance of O, and the width of the permanent magnet is Q; wherein, 1.7≥O / Q≥0.5.

[0020] Furthermore, the sidewall of the second magnetic isolation hole near the outer circumferential surface of the rotor core is set parallel to the outer circumferential surface of the rotor core and the distance is P. The width of the motor air gap formed by the rotor structure is δ, 1.7≥P / δ≥0.2.

[0021] According to a second aspect of the present invention, an electric motor is provided, comprising a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above.

[0022] According to a third aspect of the present invention, a compressor is provided, including a motor, the motor being the one described above.

[0023] The technical solution of this invention provides a rotor structure having a rotor core, multiple permanent magnets, and magnetic isolation holes. The multiple permanent magnets are uniformly distributed around the axis of the rotor core to form multiple magnetic poles, including N and S poles. At least one magnetic pole has a group of magnetic isolation holes, including a first magnetic isolation hole and a second magnetic isolation hole. Using a plane perpendicular to the axis of the rotor core as a predetermined plane, the projections of the first and second magnetic isolation holes on the predetermined plane are both strip-shaped, and the extension directions of the first and second magnetic isolation holes are intersecting. Furthermore, along the axis of the rotor core, the size and shape of the cross-section of the magnetic isolation hole group perpendicular to the axis of the rotor core remain unchanged. Through the technical solution provided by this invention, the magnetic reluctance distribution and flux direction at various points in the motor's magnetic circuit are effectively improved, thereby adjusting the air gap magnetic field distribution, improving the air gap magnetic flux density waveform, reducing the cogging effect of the motor, reducing the proportion of back EMF harmonics in the motor, reducing the torque pulsation of the motor, reducing the peak value of the electromagnetic force density of the motor, and reducing the electromagnetic vibration noise of the motor. This solves the problem of high vibration noise in existing motors. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 A schematic diagram of the rotor structure according to a first embodiment of the present invention is shown;

[0026] Figure 2 It shows Figure 1 The diagram shows the magnetic flux routing of the rotor structure.

[0027] Figure 3 A schematic diagram of the rotor structure according to a second embodiment of the present invention is shown;

[0028] Figure 4 A schematic diagram of the rotor structure according to a third embodiment of the present invention is shown;

[0029] Figure 5 A schematic diagram of a rotor structure according to a fourth embodiment of the present invention is shown;

[0030] Figure 6 A schematic diagram of a rotor structure according to a fifth embodiment of the present invention is shown;

[0031] Figure 7 A schematic diagram of a rotor structure according to a sixth embodiment of the present invention is shown;

[0032] Figure 8A comparison graph showing the measured torque ripple of an existing motor and the motor of this application is presented;

[0033] Figure 9 A comparison chart showing the measured back EMF harmonic ratios of existing motors and the motor of this application is presented;

[0034] Figure 10 A comparison graph showing the measured peak electromagnetic force density of an existing motor and the motor of this application is presented;

[0035] Figure 11 A comparison graph showing the measured total noise levels of a compressor with a conventional motor and a compressor with the motor of this application is presented; and

[0036] Figure 12 The graph shows the relationship between the measured torque ripple of the motor of this application and the value of (H+J) / D.

[0037] The above figures include the following reference numerals:

[0038] 1. Rotor core; 2. Permanent magnet; 3. Magnetic pole; 31. Magnetic pole centerline; 32. First circumferential surface; 33. Second circumferential surface; 4. Magnetic isolation hole group; 41. First magnetic isolation hole; 42. Second magnetic isolation hole; 5. Magnetic isolation bridge; 6. Magnetic conduction path; 61. First path region; 62. Second path region; 63. Third path region; 64. Fourth path region; 65. Fifth path region. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] like Figures 1 to 7 As shown, the present invention provides a rotor structure, including a rotor core 1 and a plurality of permanent magnets 2 disposed on the rotor core 1 to form a plurality of magnetic poles 3 on the rotor core 1. The plurality of magnetic poles 3 include a plurality of N poles and a plurality of S poles alternately arranged along the circumference of the rotor core 1. At least one magnetic pole 3 of the rotor core 1 is provided with a magnetic isolation hole group 4. Along the direction away from the axis of the rotor core 1, the magnetic isolation hole group 4 has a first magnetic isolation hole 41 and a second magnetic isolation hole 42 arranged at intervals. With a plane perpendicular to the axis of the rotor core 1 as a predetermined plane, the projection of the first magnetic isolation hole 41 on the predetermined plane and the projection of the second magnetic isolation hole 42 on the predetermined plane are both strip-shaped and their extension directions are intersecting.

[0041] The technical solution of the present invention provides a rotor structure having a rotor core 1, a plurality of permanent magnets 2, and a magnetic isolation hole group 4. The plurality of permanent magnets 2 are uniformly distributed on the rotor core 1 around the axis of the rotor core 1 to form a plurality of magnetic poles 3, including N poles and S poles. At least one magnetic pole 3 is provided with a magnetic isolation hole group 4, which includes a first magnetic isolation hole 41 and a second magnetic isolation hole 42. Taking a plane perpendicular to the axis of the rotor core 1 as a predetermined plane, the projections of the first magnetic isolation hole 41 and the second magnetic isolation hole 42 on the predetermined plane are both strip-shaped, and the extension directions of the first magnetic isolation hole 41 and the second magnetic isolation hole 42 are intersecting. Furthermore, along the axial direction of the rotor core 1, the size and shape of the cross section of the magnetic isolation hole group 4 perpendicular to the axial direction of the rotor core 1 remains unchanged. The technical solution provided by this invention effectively improves the magnetic reluctance distribution and magnetic flux direction at various points in the motor's magnetic circuit, thereby adjusting the air gap magnetic field distribution, improving the air gap magnetic flux density waveform, reducing the cogging effect of the motor, reducing the proportion of back EMF harmonics in the motor, reducing the torque pulsation of the motor, reducing the peak value of the electromagnetic force density of the motor, and reducing the electromagnetic vibration noise of the motor. This solves the problem of high vibration noise in existing motors.

[0042] Specifically, the rotor core 1 is made of a highly magnetic material with low magnetic resistance. Optionally, the rotor core 1 is made of silicon steel sheets, which allow magnetic lines of force to pass through easily; while the magnetic isolation hole group 4 contains non-magnetic materials such as air, which have poor magnetic permeability, high magnetic resistance, and make it difficult for magnetic lines of force to pass through. By opening this magnetic isolation hole group 4, the magnetic resistance distribution at various points in the magnetic circuit of the motor rotor structure is changed, the direction of the magnetic lines of force within the rotor structure is altered, and the air gap magnetic flux density waveform is improved, thereby reducing the proportion of back EMF harmonics, reducing motor torque pulsation, reducing electromagnetic force amplitude, and reducing motor electromagnetic vibration noise.

[0043] like Figure 2 The diagram shown illustrates the magnetic flux routing of the rotor structure according to an embodiment of the present invention. Lines with arrows indicate magnetic field lines; solid lines with arrows indicate locations with a high number of magnetic field lines, while dashed lines with arrows indicate locations with a low number of magnetic field lines. Figure 2 It can be clearly seen that fewer magnetic lines of force pass through the location of the magnetic isolation hole group 4. The magnetic isolation hole group 4 provided by the present invention effectively improves the distribution of magnetic lines of force in the rotor structure.

[0044] like Figure 1 , Figure 2 and Figure 7 As shown, the projection of the first magnetic isolation hole 41 onto the predetermined plane is perpendicular to the projection of the second magnetic isolation hole 42 onto the predetermined plane.

[0045] like Figures 1 to 7As shown, the projection of the first magnetic isolation hole 41 on the predetermined plane extends circumferentially along the rotor core 1 or along a direction perpendicular to the center line 31 of the corresponding magnetic pole 3; and / or the projection of the second magnetic isolation hole 42 on the predetermined plane extends radially along the rotor core 1 or along a direction parallel to the center line 31 of the corresponding magnetic pole 3. This improves the uniformity of magnetic permeability in both the circumferential and radial directions of the rotor core 1, thereby improving the air gap magnetic field distribution and reducing the peak electromagnetic force density and electromagnetic vibration noise of the motor.

[0046] like Figures 1 to 7 As shown, the first circumferential surface 32 is the circumferential surface with the axis of the rotor core 1 as the center axis of the first magnetic isolation hole 41 located on the side furthest from the axis of the rotor core 1, and the second circumferential surface 33 is the circumferential surface with the axis of the rotor core 1 as the center axis of the first magnetic isolation hole 41 located on the side closest to the axis of the rotor core 1; the end of the second magnetic isolation hole 42 near the axis of the rotor core 1 is located between the first circumferential surface 32 and the second circumferential surface 33; or the end of the second magnetic isolation hole 42 near the axis of the rotor core 1 is located on the first circumferential surface 32 or on the outer side of the first circumferential surface 32; or the end of the second magnetic isolation hole 42 near the axis of the rotor core 1 is located on the second circumferential surface 33 or on the inner side of the second circumferential surface 33.

[0047] Specifically, the rotor structure provided by the present invention includes a rotor core 1 and permanent magnets 2. The rotor core 1 has permanent magnet slots for accommodating the permanent magnets 2. The multiple permanent magnets 2 of the rotor structure form alternating N poles and S poles. A magnetic isolation hole group 4 is formed on the magnetic poles 3 of the rotor core 1. The magnetic isolation hole group 4 includes a first magnetic isolation hole 41 extending along the circumferential direction of the rotor core 1, and a second magnetic isolation hole 42 extending along the radial direction of the rotor.

[0048] The head of the first magnetic isolation hole 41 is close to the magnetic pole center line 31, and the tail of the first magnetic isolation hole 41 is close to the permanent magnet 2; the head of the second magnetic isolation hole 42 is close to the outer peripheral surface of the rotor core 1, and the tail of the second magnetic isolation hole 42 is close to the axis of the rotor core 1, and the head of the first magnetic isolation hole 41 is close to the tail of the second magnetic isolation hole 42.

[0049] The width of the first magnetic isolation hole 41 along the circumferential direction of the rotor core 1 is greater than its width along the radial direction of the rotor core 1, and the width of the second magnetic isolation hole 42 along the circumferential direction of the rotor core 1 is less than its width along the radial direction of the rotor core 1.

[0050] like Figure 1 As shown, the first circumferential surface 32 is the circumferential surface of the side of the first magnetic isolation hole 41 that is furthest from the axis of the rotor core 1, with the axis of the rotor core 1 as the center. The radius of the first circumferential surface 32 is A, and the radius of the rotor core 1 is B; where 0.87≥A / B≥0.5.

[0051] The radius of the first circumferential surface 32 is A, which is the maximum distance between the first magnetic isolation hole 41 and the axis of the rotor core 1. The radius of the outer circumferential surface of the rotor core 1 is B. When the value of A / B is set in the range of 0.5 to 0.87, the first magnetic isolation hole 41 can be located at the middle section of the permanent magnet 2, so as to change the direction of the magnetic flux emitted at the middle section of the permanent magnet 2, improve the magnetic flux distribution at the left and right ends of the first magnetic isolation hole 41, thereby improving the magnetic flux distribution of the rotor core 1, reducing the torque pulsation of the motor, improving the air gap magnetic flux density waveform, reducing the proportion of back EMF harmonics of the motor, and reducing the peak value of the electromagnetic force density and the electromagnetic vibration noise of the motor.

[0052] like Figure 1 As shown, the circumferential surface of the first magnetic isolation hole 41, which is closest to the axis of the rotor core 1, with the axis of the rotor core 1 as the center, is the second circumferential surface 33. The radius of the second circumferential surface 33 is C, and the radius of the rotor core 1 is B; where 0.7≥C / B≥0.4.

[0053] The radius of the second circumferential surface 33 is C, which is the minimum distance between the first magnetic isolation hole 41 and the axis of the rotor core 1. The radius of the outer circumferential surface of the rotor core 1 is B. When the value of C / B is set in the range of 0.4 to 0.7, the first magnetic isolation hole 41 can be located at the middle section of the permanent magnet 2, so as to change the direction of the magnetic flux emitted at the middle section of the permanent magnet 2, improve the magnetic flux distribution at the left and right ends of the first magnetic isolation hole 41, thereby improving the magnetic flux distribution of the rotor core 1, reducing the torque pulsation of the motor, improving the air gap magnetic flux density waveform, reducing the proportion of back EMF harmonics of the motor, and reducing the peak value of the electromagnetic force density and the electromagnetic vibration noise of the motor.

[0054] like Figure 1 As shown, the projection of the first magnetic isolation hole 41 onto the predetermined plane is a first rectangular structure, the length of the first rectangular structure is D, and the width of the first rectangular structure is E; where 5.3≥D / E≥2.

[0055] The length D of the first rectangular structure is the width of the first magnetic isolation hole 41 in the circumferential direction of the rotor core; the width E of the first rectangular structure is the width of the first magnetic isolation hole 41 in the radial direction of the rotor core. The width of the first magnetic isolation hole 41 in the circumferential direction of the rotor core is greater than its width in the radial direction of the rotor core.

[0056] The first magnetic isolation hole 41 mainly changes the direction of the magnetic flux emitted from the middle section of the permanent magnet 2. If the width of the first magnetic isolation hole 41 in the radial direction of the rotor core is too large, the magnetic resistance of the first magnetic isolation hole 41 will be too large, and the obstruction effect on the magnetic flux will also be too large, which is not conducive to the transmission of magnetic energy.

[0057] When the D / E value is set in the range of 2 to 5.3, it can improve the air gap magnetic flux density waveform while ensuring the motor torque output, thereby reducing the proportion of back EMF harmonics, the peak value of electromagnetic force density, and the electromagnetic vibration noise of the motor.

[0058] like Figure 1 As shown, the projection of the second magnetic isolation hole 42 onto the predetermined plane is a second rectangular structure, the length of which is F and the width of which is G; where 7≥F / G≥3.

[0059] The length F of the second rectangular structure is the width of the second magnetic isolation hole 42 in the radial direction of the rotor core 1; the width G of the second rectangular structure is the width of the second magnetic isolation hole 42 in the circumferential direction of the rotor core 1, and the width of the second magnetic isolation hole 42 in the circumferential direction of the rotor core 1 is less than its width in the radial direction of the rotor core 1.

[0060] The head of the second magnetic isolation hole 42 is close to the outer peripheral surface of the rotor core 1. The second magnetic isolation hole 42 is filled with a non-magnetic material with a large magnetic resistance. The second magnetic isolation hole 42 is surrounded by a magnetically conductive material such as the iron core with a small magnetic resistance.

[0061] When the value of F / G is set in the range of 3 to 7, it can improve the magnetic flux density distribution of the air gaps corresponding to the outer circumference of the rotor core 1, thereby reducing the torque pulsation of the motor, reducing the peak electromagnetic force density of the motor and the electromagnetic vibration noise of the motor.

[0062] like Figure 1 As shown, the length of the projection of the first magnetic isolation hole 41 onto the predetermined plane is D, the distance between the point of the projection of the first magnetic isolation hole 41 onto the predetermined plane closest to the permanent magnet 2 and the permanent magnet 2 is H, and the minimum distance between the first magnetic isolation hole 41 and the second magnetic isolation hole 42 is J; where 1.8≥(H+J) / D≥0.5.

[0063] The projection of the first magnetic isolation hole 41 onto the predetermined plane is a strip shape. The length D of the projection of the first magnetic isolation hole 41 onto the predetermined plane is its width in the circumferential direction of the rotor core. There is a distance H between the first magnetic isolation hole 41 and the permanent magnet 2, and a distance J between the first magnetic isolation hole 41 and the second magnetic isolation hole 42.

[0064] Partial magnetic flux transmission is allowed at the magnetic conduction path 6 between the first magnetic isolation hole 41 and the permanent magnet. Partial magnetic flux transmission is allowed at the magnetic conduction path 6 between the first magnetic isolation hole 41 and the second magnetic isolation hole 42. The first magnetic isolation hole 41 and the second magnetic isolation hole 42 are filled with non-magnetic material with high magnetic resistance, and very little magnetic flux is transmitted to the outer peripheral surface of the rotor core 1 through them.

[0065] When the value of (H+J) / D is set in the range of 0.5 to 1.8, the magnetic field distribution of the rotor structure is effectively improved, which in turn improves the air gap magnetic field distribution, reduces harmonic and harmonic losses, improves the efficiency of the motor, and reduces the peak electromagnetic force density and electromagnetic vibration noise of the motor.

[0066] like Figure 12 As shown in the figure, the measured torque pulsation of the motor of this application varies with the value of (H+J) / D of the magnetic isolation hole group 4. Figure 12 As can be seen, when the value of (H+J) / D of the magnetic isolation hole group 4 is in the range of 0.5 to 1.8, the torque pulsation of the motor of this application is significantly reduced.

[0067] like Figures 1 to 7 As shown, each magnetic pole 3 is provided with multiple magnetic isolation hole groups 4, which are arranged in pairs. The two pairs of magnetic isolation hole groups 4 are located on both sides of the magnetic pole center line 31 of the magnetic pole 3.

[0068] like Figures 1 to 7 As shown, the first magnetic isolation hole 41 of the two pairs of magnetic isolation hole groups 4 is symmetrically arranged with respect to the magnetic pole center line 31 of the magnetic pole 3; the second magnetic isolation hole 42 of the two pairs of magnetic isolation hole groups 4 is symmetrically arranged with respect to the magnetic pole center line 31 of the magnetic pole 3.

[0069] Specifically, each magnetic pole 3 includes at least two sets of magnetic isolation holes 4 to divide the magnetic pole 3 into multiple magnetic conductive paths 6.

[0070] The first magnetic isolation hole 41 and the second magnetic isolation hole 42 of a single magnetic isolation hole group 4 are both located on the same side of the magnetic pole center line. The first magnetic isolation hole 41 of the two magnetic isolation hole groups 4 are symmetrical about the magnetic pole center line 31, and the second magnetic isolation hole 42 of the two magnetic isolation hole groups 4 are symmetrical about the magnetic pole center line 31. The two groups of magnetic isolation holes 4 divide the magnetic pole 3 into five magnetic conduction paths 6. The magnetic conduction path 6 includes a first path region 61, a second path region 62, a third path region 63, a fourth path region 64, and a fifth path region 65 to improve the distribution of magnetic field lines on the magnetic pole 3.

[0071] On the one hand, the magnetic flux at each magnetic conduction path 6 is adjusted by the magnetic isolation hole group 4. On the other hand, the magnetic flux density at each magnetic conduction path 6 is adjusted by arranging the magnetic isolation holes of the magnetic isolation hole group 4 along the circumferential and radial directions of the rotor core 1, thereby improving the air gap magnetic flux waveform, reducing the motor torque pulsation, reducing the peak value of the electromagnetic force density of the motor, and reducing the electromagnetic vibration noise of the motor.

[0072] The first magnetic isolation hole 41 of the two magnetic isolation hole groups 4 forms a first path region 61 and a second path region 62 with the two permanent magnets 2 respectively. The first magnetic isolation hole 41 of the two magnetic isolation hole groups 4 forms a third path region 63 and a fourth path region 64 with the corresponding second magnetic isolation hole 42 respectively. The second magnetic isolation hole 42 of the two magnetic isolation hole groups 4 forms a fifth path region 65. In this way, the magnetic flux and magnetic flux direction on the rotor core 1 are improved, thereby improving the air gap magnetic field distribution, reducing the torque pulsation of the motor, reducing the peak electromagnetic force density of the motor, and reducing the electromagnetic vibration noise of the motor.

[0073] like Figure 3 and Figure 4 As shown, the projection of the first magnetic isolation hole 41 onto the predetermined plane extends perpendicularly to the magnetic pole centerline 31 of the magnetic pole 3. The centerline of the projection of the first magnetic isolation hole 41 onto the predetermined plane along its extension direction is the first centerline, and the centerline of the projection of the second magnetic isolation hole 42 onto the predetermined plane along its extension direction is the second centerline. The angle between the first centerline and the second centerline is K, and the angle between the permanent magnets located on both sides of the corresponding magnetic pole 3 is L. Wherein, 1.6≥K / L≥0.4.

[0074] Preferably, the projections of the first magnetic isolation hole 41 and the second magnetic isolation hole 42 on the predetermined plane are both strip-shaped, and the extension direction of the projection of the first magnetic isolation hole 41 on the predetermined plane is perpendicular to the magnetic pole center line 31. The angle between the extension direction of the projection of the first magnetic isolation hole 41 on the predetermined plane and the extension direction of the projection of the second magnetic isolation hole 42 on the predetermined plane is K, and the included angle between the two permanent magnets 2 of each magnetic pole 3 is L.

[0075] When the value of K / L is set in the range of 0.4 to 1.6, the first magnetic isolation hole 41 extends along the circumferential direction of the rotor core 1 to adjust the magnetic permeability of the rotor core 1 in the circumferential direction. The second magnetic isolation hole 42 extends both along the circumferential direction and the radial direction of the rotor core 1, further improving the uniformity of the magnetic permeability in the circumferential and radial directions of the rotor core 1. This improves the air gap magnetic field distribution, reduces harmonics, and reduces the peak value of the electromagnetic force density and the electromagnetic vibration noise of the motor.

[0076] like Figure 5 and Figure 6 As shown, the projection of the second magnetic isolation hole 42 onto the predetermined plane is parallel to the magnetic pole centerline 31 of the magnetic pole 3. The centerline of the projection of the first magnetic isolation hole 41 onto the predetermined plane along its extension direction is the first centerline, and the centerline of the projection of the second magnetic isolation hole 42 onto the predetermined plane along its extension direction is the second centerline. The angle between the first centerline and the second centerline is M, and the angle between the permanent magnets located on both sides of the corresponding magnetic pole 3 is L. Wherein, 2.4≥M / L≥0.5.

[0077] Preferably, the projections of the first magnetic isolation hole 41 and the second magnetic isolation hole 42 on the predetermined plane are both strip-shaped, and the extension direction of the projection of the second magnetic isolation hole 42 on the predetermined plane is parallel to the magnetic pole center line 31. The angle between the extension direction of the projection of the first magnetic isolation hole 41 on the predetermined plane and the extension direction of the projection of the second magnetic isolation hole 42 on the predetermined plane is M, and the included angle between the two permanent magnets 2 of each magnetic pole 3 is L.

[0078] When the value of M / L is set in the range of 0.5 to 2.4, the second magnetic isolation hole 42 extends along the radial direction of the rotor core 1 to adjust the radial magnetic permeability of the rotor core 1, while the first magnetic isolation hole 41 extends along both the circumferential and radial directions of the rotor core 1, further improving the uniformity of the magnetic permeability in the circumferential and radial directions of the rotor core 1, thereby improving the air gap magnetic field distribution, reducing harmonics, and reducing the peak electromagnetic force density and electromagnetic vibration noise of the motor.

[0079] like Figure 5 As shown, the first magnetic isolation hole 41 is arranged parallel to the permanent magnet 2 on the side wall near the permanent magnet 2 and at a distance of O. The width of the permanent magnet 2 is Q; where 1.7≥O / Q≥0.5.

[0080] Specifically, there is a distance O between the first magnetic isolation hole 41 and the permanent magnet 2, and the width (i.e., thickness) of the permanent magnet is Q. When the value of O / Q is set in the range of 0.5 to 1.7, the magnetic flux transmitted to the inner and outer sides of the first magnetic isolation hole 41 through this distance O can be effectively improved. This allows more magnetic flux on the side of the permanent magnet 2 closer to the axis of the rotor core 1 to be transmitted to the middle of the magnetic pole 3, and more magnetic flux on the side of the permanent magnet 2 closer to the outer circumference of the rotor core 1 to be transmitted to both ends of the magnetic pole 3. This improves the magnetic field distribution inside the rotor, improves the air gap magnetic field distribution, reduces harmonic and harmonic losses, improves motor efficiency, and reduces the peak electromagnetic force density and electromagnetic vibration noise of the motor.

[0081] Preferably, the sidewall of the second magnetic isolation hole 42 near the outer peripheral surface of the rotor core 1 is parallel to the outer peripheral surface of the rotor core 1 and the distance is P. The width of the motor air gap formed by the rotor structure is δ, 1.7≥P / δ≥0.2.

[0082] In this context, the width δ of the air gap in the motor formed by the rotor structure represents the gap between the rotor and stator, while the air gap magnetic flux density refers to the magnetic induction intensity of the magnetic field present in the air gap. The distance P between the side wall of the second magnetic isolation hole 42 near the outer circumferential surface of the rotor core 1 and the outer circumferential surface of the rotor core 1 is the magnetic isolation bridge 5. The magnetic isolation bridge 5 allows a portion of the magnetic flux lines to be transmitted into the air gap. Along the circumferential direction of the rotor core 1, the width of the magnetic isolation bridge 5 in the radial direction of the rotor core 1 is uniform. When the value of P / δ is set within the range of 0.2 to 1.7, the magnetic flux transmitted at the magnetic isolation bridge 5 is optimal, the air gap magnetic flux density waveform is optimally improved, the peak electromagnetic force density of the motor is minimized, and the vibration and noise of the motor are also minimized.

[0083] The present invention also provides an electric motor, including a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above. This enables the vibration and noise of the electric motor to be reduced.

[0084] The present invention also provides a compressor, including a motor, wherein the motor is the motor described above. This enables the compressor to reduce vibration and noise.

[0085] like Figure 8 As shown in the diagram, a comparison of the measured torque ripple of an existing motor and the motor of this application is presented. Figure 8 It is evident that the torque ripple range of the motor in this application is much smaller than that of existing motors.

[0086] like Figure 9 The diagram shows a comparison of the measured back EMF harmonic ratios of existing motors and the motor of this application. Figure 9 It can be clearly seen that the back EMF harmonic ratio of the motor in this application is much smaller than that of existing motors.

[0087] like Figure 10 As shown in the figure, a comparison chart of the peak electromagnetic force density of the existing motor and the motor of this application is presented. Figure 10 It can be clearly seen that the peak electromagnetic force density of the motor in this application is much smaller than that of existing motors.

[0088] like Figure 11 The graph shown compares the total noise levels of a compressor with a conventional motor and a compressor with the motor described in this application. Figure 11 It is evident that the total noise level of the compressor with the motor of this application is much lower than that of the compressor with the existing motor.

[0089] In this invention, the rotor structure includes a rotor core 1 and permanent magnets 2. The permanent magnets 2 are disposed in permanent magnet slots on the rotor core 1, forming alternating N and S poles. A magnetic isolation hole group 4 is formed on the magnetic poles 3 of the rotor core 1. The magnetic isolation hole group 4 includes a first magnetic isolation hole 41 extending circumferentially along the rotor core 1 and a second magnetic isolation hole 42 extending radially along the rotor core 1. The first and second magnetic isolation holes 41 are not connected. The first magnetic isolation hole 41 is located on the side of the magnetic isolation hole group 4 closest to the axis of the rotor core 1, and the second magnetic isolation hole 42 is located on the side of the magnetic isolation hole group 4 closest to the outer circumferential surface of the rotor core 1. Furthermore, the second magnetic isolation hole 42 is closer to the center line 31 of the magnetic pole than the first magnetic isolation hole 41. This structure of the magnetic isolation hole group 4 alters the magnetic field distribution of the rotor structure.

[0090] Permanent magnet motors generate their main magnetic field using permanent magnets 2. They are characterized by high air gap magnetic flux density, high efficiency, small size, high power density, simple structure, and high reliability, making them widely used in various industries. However, in permanent magnet synchronous motors, the permanent magnets 2, made of a fixed grade of material, have a constant magnetic energy product, making it difficult to adjust the air gap magnetic field. Furthermore, the motor's cogging structure results in a high harmonic content in the air gap magnetic flux density and back electromotive force, leading to a large peak electromagnetic force density and consequently, significant torque pulsation and vibration noise.

[0091] This invention, by creating a magnetic isolation hole group 4 on the rotor core 1, alters the magnetic reluctance distribution of the magnetic circuit throughout the motor, thereby reducing the cogging effect, torque pulsation, and air gap magnetic flux density waveform. Simultaneously, it reduces the proportion of back EMF harmonics, lowers the peak electromagnetic force density, and reduces electromagnetic vibration and noise. This invention solves the problems of high air gap magnetic flux density and back EMF waveform distortion, large back EMF harmonic proportion, large motor torque pulsation, large motor electromagnetic force, and large motor vibration and noise in permanent magnet synchronous motors.

[0092] This invention provides a rotor structure having a rotor core 1, multiple permanent magnets 2, and a magnetic isolation hole group 4. The multiple permanent magnets 2 are uniformly distributed around the axis of the rotor core 1 to form multiple magnetic poles 3, including N poles and S poles. At least one magnetic pole 3 has a magnetic isolation hole group 4, which includes a first magnetic isolation hole 41 and a second magnetic isolation hole 42. Using a plane perpendicular to the axis of the rotor core 1 as a predetermined plane, the projections of the first magnetic isolation hole 41 and the second magnetic isolation hole 42 onto the predetermined plane are both strip-shaped, and the extension directions of the first magnetic isolation hole 41 and the second magnetic isolation hole 42 are intersecting. Furthermore, along the axial direction of the rotor core 1, the size and shape of the cross-section of the magnetic isolation hole group 4 perpendicular to the axial direction of the rotor core 1 remain unchanged. The technical solution provided by this invention effectively improves the magnetic reluctance distribution and magnetic flux direction at various points in the motor's magnetic circuit, thereby adjusting the air gap magnetic field distribution, improving the air gap magnetic flux density waveform, reducing the cogging effect of the motor, reducing the proportion of back EMF harmonics in the motor, reducing the torque pulsation of the motor, reducing the peak value of the electromagnetic force density of the motor, and reducing the electromagnetic vibration noise of the motor. This solves the problem of high vibration noise in existing motors.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rotor structure comprising a rotor core (1) and a plurality of permanent magnets (2) disposed on the rotor core (1) to form a plurality of magnetic poles (3) on the rotor core (1), the plurality of magnetic poles (3) comprising a plurality of N poles and a plurality of S poles alternately disposed circumferentially along the rotor core (1); characterized in that, At least one of the magnetic poles (3) of the rotor core (1) is provided with a magnetic isolation hole group (4), and along the direction away from the axis of the rotor core (1), the magnetic isolation hole group (4) has a first magnetic isolation hole (41) and a second magnetic isolation hole (42) arranged at intervals. With the plane perpendicular to the axis of the rotor core (1) as the predetermined plane, the projection of the first magnetic isolation hole (41) on the predetermined plane and the projection of the second magnetic isolation hole (42) on the predetermined plane are both strip-shaped and their extension directions are intersecting. Each of the magnetic poles (3) is provided with a plurality of magnetic isolation hole groups (4), and the plurality of magnetic isolation hole groups (4) are arranged in pairs. The two pairs of magnetic isolation hole groups (4) are respectively located on both sides of the magnetic pole center line (31) of the magnetic pole (3). The first magnetic isolation hole (41) of the two pairs of magnetic isolation hole groups (4) is symmetrically arranged with respect to the magnetic pole center line (31) of the magnetic pole (3). The second magnetic isolation hole (42) of the two pairs of magnetic isolation hole groups (4) is symmetrically arranged with respect to the magnetic pole center line (31) of the magnetic pole (3). The projection of the first magnetic isolation hole (41) on the predetermined plane extends circumferentially along the rotor core (1) or in a direction perpendicular to the magnetic pole center line (31) of the corresponding magnetic pole (3); the projection of the second magnetic isolation hole (42) on the predetermined plane extends radially along the rotor core (1) or in a direction parallel to the magnetic pole center line (31) of the corresponding magnetic pole (3). In each of the magnetic isolation hole groups (4), the first magnetic isolation hole (41) is located on the side of the second magnetic isolation hole (42) away from the magnetic pole center line (31) of the magnetic pole (3); The first circumferential surface (32) of the first magnetic isolation hole (41) is located on the side furthest from the axis of the rotor core (1) with the axis of the rotor core (1) as the center axis. The radius of the first circumferential surface (32) is A, and the radius of the rotor core (1) is B; 0.87≥A / B≥0.5; The circumferential surface of the first magnetic isolation hole (41) closest to the axis of the rotor core (1) is the second circumferential surface (33) with the axis of the rotor core (1) as the center axis, and the radius of the second circumferential surface (33) is C; 0.7≥C / B≥0.

4.

2. The rotor structure according to claim 1, characterized in that, The projection of the first magnetic isolation hole (41) on the predetermined plane is perpendicular to the projection of the second magnetic isolation hole (42) on the predetermined plane.

3. The rotor structure according to claim 1, characterized in that, The first circumferential surface (32) is the circumferential surface with the axis of the rotor core (1) as the center axis, located on the side of the first magnetic isolation hole (41) that is furthest from the axis of the rotor core (1). The second circumferential surface (33) is the circumferential surface with the axis of the rotor core (1) as the center axis, located on the side of the first magnetic isolation hole (41) that is closest to the axis of the rotor core (1). The second magnetic isolation hole (42) is located between the first circumferential surface (32) and the second circumferential surface (33) at one end near the axis of the rotor core (1); or The second magnetic isolation hole (42) has one end near the axis of the rotor core (1) located on the first circumferential surface (32) or on the outer side of the first circumferential surface (32); or The end of the second magnetic isolation hole (42) near the axis of the rotor core (1) is located on the second circumferential surface (33) or inside the second circumferential surface (33).

4. The rotor structure according to claim 1, characterized in that, The projection of the first magnetic isolation hole (41) on the predetermined plane is a first rectangular structure, the length of the first rectangular structure is D, and the width of the first rectangular structure is E; wherein, 5.3≥D / E≥2.

5. The rotor structure according to claim 1, characterized in that, The projection of the second magnetic isolation hole (42) on the predetermined plane is a second rectangular structure, the length of the second rectangular structure is F, and the width of the second rectangular structure is G; wherein, 7≥F / G≥3.

6. The rotor structure according to claim 1, characterized in that, The length of the projection of the first magnetic isolation hole (41) on the predetermined plane is D, the distance between the point of the projection of the first magnetic isolation hole (41) on the predetermined plane closest to the permanent magnet (2) and the permanent magnet (2) is H, and the minimum distance between the first magnetic isolation hole (41) and the second magnetic isolation hole (42) is J; wherein, 1.8≥(H+J) / D≥0.

5.

7. The rotor structure according to claim 1, characterized in that, The projection of the first magnetic isolation hole (41) onto the predetermined plane extends perpendicularly to the magnetic pole centerline (31) of the magnetic pole (3). The centerline of the projection of the first magnetic isolation hole (41) onto the predetermined plane along its extension direction is the first centerline, and the centerline of the projection of the second magnetic isolation hole (42) onto the predetermined plane along its extension direction is the second centerline. The angle between the first centerline and the second centerline is K, and the angle between the permanent magnets located on both sides of the corresponding magnetic pole (3) is L. Wherein, 1.6≥K / L≥0.

4.

8. The rotor structure according to claim 1, characterized in that, The projection of the second magnetic isolation hole (42) on the predetermined plane is parallel to the magnetic pole centerline (31) of the magnetic pole (3). The centerline of the projection of the first magnetic isolation hole (41) on the predetermined plane along its extension direction is the first centerline, and the centerline of the projection of the second magnetic isolation hole (42) on the predetermined plane along its extension direction is the second centerline. The angle between the first centerline and the second centerline is M, and the angle between the permanent magnets located on both sides of the corresponding magnetic pole (3) is L. Wherein, 2.4≥M / L≥0.

5.

9. The rotor structure according to claim 1, characterized in that, The first magnetic isolation hole (41) is arranged parallel to the permanent magnet (2) on the side wall of the permanent magnet (2) and at a distance of O. The width of the permanent magnet (2) is Q; wherein, 1.7≥O / Q≥0.

5.

10. The rotor structure according to claim 1, characterized in that, The second magnetic isolation hole (42) is located near the outer peripheral surface of the rotor core (1) and is parallel to the outer peripheral surface of the rotor core (1) with a distance of P. The width of the motor air gap of the motor formed by the rotor structure is δ, 1.7≥P / δ≥0.

2.

11. An electric motor, comprising a stator structure and a rotor structure, characterized in that, The rotor structure is the rotor structure according to any one of claims 1 to 10.

12. A compressor, comprising a motor, characterized in that, The motor is the motor described in claim 11.

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