A rotor of an axial flux permanent magnet motor

Abstract

This invention discloses a rotor for an axial flux permanent magnet motor, comprising a rotor core. The rotor core has radially arranged magnetic pole mounting slots on its side, and magnetic poles are disposed within these slots. Each magnetic pole includes at least one group of magnetic steel bars, each group consisting of several horizontally joined magnetic steel bars. The length direction of the magnetic steel bars is radially arranged along the rotor core. The magnetic steel bar located at the radial center of the magnetic pole has the greatest thickness, and the other magnetic steel bars are symmetrically arranged on both sides of the radial center of the magnetic pole. The thickness of the magnetic steel bars gradually decreases from the radial center of the magnetic pole towards both sides. The rotor of this axial flux permanent magnet motor exhibits better sinusoidal magnetic field strength, generates fewer harmonics during rotor operation, and reduces vibration noise.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a rotor of an axial flux permanent magnet motor. Background Technology

[0002] An axial magnetic field motor, also called a disc motor, is a motor in which the main magnetic field is along the direction of the rotation axis.

[0003] Current axial flux motor rotors generally employ a surface-mounted permanent magnet structure. In this type of rotor, the magnetic pole 01 is a magnet steel structure with a constant thickness, such as... Figure 1 As shown, all magnets use the same permanent magnet material, and the magnetic flux density along the axial direction of the motor is the same, resulting in poor sinusoidal magnetic field and the generation of a large number of harmonics during operation. The presence of these harmonics will reduce the operating performance of the motor, such as cogging torque, large torque fluctuation, and large vibration noise. Summary of the Invention

[0004] In view of this, the present invention provides a rotor for an axial flux permanent magnet motor with better sinusoidal magnetic field, fewer harmonics generated during rotor operation, and reduced vibration noise.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A rotor for an axial flux permanent magnet motor includes a rotor core, wherein a radially arranged magnetic pole mounting groove is provided on the side of the rotor core, and a magnetic pole is disposed in the magnetic pole mounting groove.

[0007] Each of the magnetic poles includes at least one group of magnetic steel bars, each group of magnetic steel bars being horizontally spliced ​​together from several magnetic steel bars, the length direction of the magnetic steel bars being arranged along the radial direction of the rotor core;

[0008] The magnetic strip located at the radial center of the magnetic pole has the greatest thickness, and the other magnetic strips are symmetrically arranged on both sides of the radial center of the magnetic pole. The thickness of the magnetic strips gradually decreases from the radial center of the magnetic pole to both sides.

[0009] Optionally, the magnetic strip is a rectangular strip, and the horizontal center planes of multiple magnetic strips forming the same magnetic pole coincide.

[0010] Optionally, the magnetic pole is formed by splicing multiple groups of magnetic steel bars along the radial direction of the rotor core, and different groups of magnetic steel bars forming a magnetic pole are bonded together.

[0011] Optionally, the longitudinal center planes of the different groups of magnetic strips that form a magnetic pole coincide;

[0012] The different magnetic bar groups have the same radial length along the rotor core.

[0013] Optionally, the magnetic pole is formed by splicing three groups of magnetic steel bars along the radial direction of the rotor core, and each group of magnetic steel bars is formed by splicing five magnetic steel bars.

[0014] Optionally, the rotor core includes several rotor core segments, which are coaxially sleeved together, and the end faces of the multiple rotor core segments are located on the same plane, with corresponding magnetic pole mounting slots provided for adjacent rotor core segments;

[0015] The inner diameter of the outer rotor core segment is the same as the outer diameter of the adjacent inner rotor core segment;

[0016] Each rotor core segment has a corresponding magnetic pole mounting slot for installing a set of magnetic steel strips, and the corresponding magnetic steel strip sets of adjacent rotor core segments are bonded together.

[0017] Optionally, a protective sleeve is provided on the outer side of the outermost rotor core segment, and the protective sleeve is interference-fitted to the outer surface of the rotor core.

[0018] Optionally, the magnet strip is bonded to the magnetic pole mounting groove.

[0019] Optionally, the different magnetic bar groups may have the same or different widths along the circumference of the rotor core.

[0020] Optionally, the rotor core is made of silicon steel strip rolled into shape or a soft magnetic powder core integrally formed.

[0021] As can be seen from the above technical solution, the rotor of the axial flux permanent magnet motor provided by the present invention has magnetic poles composed of groups of magnetic steel bars. Each group of magnetic steel bars is spliced ​​together from several magnetic steel bars, and the multiple magnetic steel bars that form a magnetic pole are arranged horizontally. The magnetic steel bar located at the radial center of the magnetic pole has the greatest thickness, and the other magnetic steel bars are symmetrically arranged on both sides of the magnetic steel bar at the center. The thickness of the magnetic steel bars forming a magnetic pole gradually decreases from the radial center of the magnetic pole to both sides. In the present invention, the middle part of the magnetic pole uses magnetic steel bars with high magnetization thickness, and the magnetization thickness of the magnetic steel bars on both sides gradually decreases. At this time, the magnetic flux density of the magnetic steel bars forming the magnetic pole gradually decreases from the center to both sides, thereby improving the sinusoidal nature of the motor's magnetic field. The better the sinusoidal nature of the magnetic field of the magnetic pole, the fewer harmonics generated during rotor operation, improving the motor's operating performance, reducing torque fluctuations, and minimizing vibration and noise. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the magnetic pole structure of an axial flux permanent magnet motor in the prior art;

[0024] Figure 2 A schematic diagram of the rotor structure of an axial flux permanent magnet motor provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the rotor core structure provided in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of a magnetic pole provided in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of a magnetic pole at one angle according to an embodiment of the present invention;

[0028] Figure 6 for Figure 5 A schematic diagram of another angle of the magnetic poles provided in the embodiment;

[0029] Figure 7 for Figure 5 A schematic diagram of the rotor core corresponding to the magnetic poles;

[0030] Figure 8 This is a structural schematic diagram of a magnetic pole at one angle provided in another embodiment of the present invention;

[0031] Figure 9 for Figure 8 A schematic diagram of another angle of the magnetic poles provided in the embodiment;

[0032] Figure 10 for Figure 8 A schematic diagram of the rotor core corresponding to the magnetic poles;

[0033] Figure 11 A schematic diagram of a magnetic pole at one angle provided in another embodiment of the present invention;

[0034] Figure 12 for Figure 11 A schematic diagram of another angle of the magnetic poles provided in the embodiment;

[0035] Figure 13 for Figure 11A schematic diagram of the rotor core corresponding to the magnetic poles;

[0036] Figure 14 A comparison diagram of the magnetic flux density waveform of the rotor of the axial flux permanent magnet motor provided in an embodiment of the present invention.

[0037] in:

[0038] 01. Magnetic poles

[0039] 1. Rotor core; 101. Magnetic pole mounting slot; 102. Rotor core assembly; 2. Magnetic pole; 201. Magnetic steel bar; 3. Protective sleeve. Detailed Implementation

[0040] This invention discloses a rotor for an axial flux permanent magnet motor, which has better sinusoidal magnetic field and generates fewer harmonics during rotor operation, thereby reducing vibration and noise.

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] See Figures 2 to 4 The rotor of the axial flux permanent magnet motor of the present invention includes a rotor core 1, and a magnetic pole mounting groove 101 arranged radially is provided on the side of the rotor core 1, and a magnetic pole 2 is provided in the magnetic pole mounting groove 101.

[0043] The magnetic pole 2 includes at least one group of magnetic steel bars. Each group of magnetic steel bars is composed of several magnetic steel bars 201 spliced ​​together. The length direction of the magnetic steel bars 201 is arranged radially along the rotor core 1, that is, multiple magnetic steel bars 201 are spliced ​​circumferentially, and the splicing surface is arranged radially. The multiple magnetic steel bars 201 spliced ​​to form a magnetic pole 2 are arranged horizontally. The magnetic steel bar 201 located at the radial center of the magnetic pole 2 has the largest thickness, and the other magnetic steel bars 201 are symmetrically arranged on both sides of the radial center of the magnetic pole 2. The thickness of the magnetic steel bars 201 forming a magnetic pole 2 gradually decreases from the radial center of the magnetic pole 2 to both sides. Here, the radial direction of the magnetic pole 2 refers to the direction that coincides with the radial direction of the rotor core 1. The rotor core 1 is a hollow disc-shaped structure, and the magnetic pole mounting groove 101 is provided on the side of the rotor core 1.

[0044] The rotor of the axial flux permanent magnet motor of the present invention comprises magnetic poles 2 composed of groups of magnetic steel bars. Each group of magnetic steel bars is spliced ​​together from several magnetic steel bars 201. The multiple magnetic steel bars 201 forming a magnetic pole 2 are arranged horizontally, with the magnetic steel bar 201 at the radial center of the magnetic pole 2 having the greatest thickness. The other magnetic steel bars 201 are symmetrically arranged on both sides of the central magnetic steel bar 201. The thickness of the magnetic steel bars 201 forming a magnetic pole 2 gradually decreases from the radial center towards both sides. The middle part of the magnetic pole 2 of the present invention uses magnetic steel bars 201 with high magnetization thickness, while the magnetization thickness of the magnetic steel bars 201 on both sides gradually decreases. At this time, the magnetic flux density of the magnetic steel bars 201 forming the magnetic pole 2 gradually decreases from the center towards both sides, thereby improving the sinusoidal nature of the magnetic field of the magnetic pole 2. The better the sinusoidal nature of the magnetic field of the magnetic pole 2, the fewer harmonics generated during rotor operation, improving the motor's operating performance, reducing torque fluctuations, and minimizing vibration noise.

[0045] Specifically, the magnetic strip 201 is a rectangular strip, and the horizontal center planes of multiple magnetic strips 201 forming the same magnetic pole 2 coincide, such as... Figure 4 As shown.

[0046] In one embodiment, the magnetic pole 2 is formed by splicing multiple groups of magnetic steel bars along the radial direction of the rotor core 1, with different groups of magnetic steel bars forming a magnetic pole 2 bonded together. The magnetic steel bars 201 of the same group are bonded together and then inserted into the magnetic pole mounting groove 101. In other embodiments, the magnetic steel bars 201 of the same group can also be directly inserted into the magnetic pole mounting groove 101 and then bonded together.

[0047] The longitudinal center planes of the different magnetic steel bar groups that make up a magnetic pole 2 coincide, so as to form a symmetrical magnetic pole 2. The different magnetic steel bar groups have the same radial length along the rotor core 1.

[0048] Furthermore, the rotor core 1 includes several rotor core segments 102, where "several" refers to two or more segments. These segments are coaxially mounted together, with their end faces on the same plane. Adjacent rotor core segments 102 have corresponding magnetic pole mounting slots 101, meaning the number of slots 101 on the different rotor core segments 102 mounted together is the same, and their positions are along the same radial direction of the rotor core 1. Each rotor core segment 102 has a corresponding magnetic pole mounting slot 101 for mounting a set of magnetic steel bars, and the corresponding magnetic steel bar sets on adjacent rotor core segments 102 are bonded together. The inner diameter of the outer rotor core segment 102 is the same as the outer diameter of the adjacent inner rotor core segment 102, ensuring a tight fit.

[0049] To improve the installation reliability of the magnetic poles 2 during rotor rotation, a protective sleeve 3 is fitted around the outermost rotor core segment 102. The protective sleeve 3 is interference-fitted onto the outer surface of the rotor core segment 102. Because of the protective sleeve 3, the magnetic poles 2 within the magnetic pole mounting groove 101 are prevented from detaching due to centrifugal force.

[0050] The rotor core 1 is made of silicon steel strip rolled into shape or soft magnetic powder core integrally formed.

[0051] Example 1

[0052] In this embodiment, such as Figure 5 and Figure 6 As shown, each group of magnetic steel strips includes five magnetic steel strips 201. The magnetic poles 2 are arranged radially as three permanent magnet segments, each permanent magnet segment constituting one group of magnetic steel strips. Adjacent groups of magnetic steel strips are bonded together. The width of multiple groups of magnetic steel strips gradually decreases from the outer edge of the rotor core 1 towards the center (from the outside in), L1 > L2 > L3. In special cases, such as... Figure 6 As shown, L1 > L2 ≥ L3, and the arrows in the figure point in the direction from the outside to the inside. Setting the magnetic poles 2 as permanent magnet segments of varying widths can reduce cogging torque. Correspondingly, the rotor core 1 is a composite core structure, specifically comprising three coaxially nested rotor core segments 102, with the end faces of the three rotor core segments 102 located on the same plane, as shown... Figure 7 The diagram shows an exploded view of the three rotor core components 102. Each set of magnet bars is installed in a pole mounting slot 101 of one rotor core component 102. The innermost rotor core component 102 has a pole mounting slot 101 corresponding to the innermost set of magnet bars, and the length of the pole mounting slot 101 is the same as the length of the innermost set of magnet bars. Here, the slot length refers to the radial dimension of the pole mounting slot 101 along the rotor core 1. The pole mounting slot 101 of the middle rotor core component 102 is installed on the middle set of magnet bars, and the length of the pole mounting slot 101 of the middle rotor core component 102 is the same as the length of the middle set of magnet bars, and so on. To improve the installation reliability of the magnet bars during rotor rotation, a protective sleeve 3 is provided on the outermost rotor core component 102.

[0053] Example 2

[0054] In this embodiment, such as Figure 8 and Figure 9As shown, each group of magnetic strips includes five magnetic strips 201. The magnetic pole 2 is arranged radially as three permanent magnet segments, each permanent magnet segment constituting one group of magnetic strips. Adjacent groups of magnetic strips are bonded together. Of the three groups of magnetic strips forming the magnetic pole 2, the middle group is the widest, and the widths of the two groups on either side are smaller than the width of the middle group. Figure 9 As shown in the figure, the arrows point from the inside out, that is, from the center of the rotor core 1 to the edge. Figure 10 for Figure 9 The diagram shows the structure of the magnetic pole 2 mounted on the rotor core 1. Accordingly, in this embodiment, the rotor core 1 is a composite core structure, comprising three rotor core components 102. These three rotor core components 102 are coaxially mounted together, and the end faces of the three rotor core components 102 are located on the same plane. Figure 10 The image shows an exploded view of the three rotor core components 102 after installation. Each group of magnet bars is installed in a pole mounting slot 101 of one rotor core component 102. The innermost pole mounting slot 101 of the rotor core component 102 corresponds to the innermost magnet bar group, and the middle pole mounting slot 101 of the rotor core component 102 corresponds to the middle magnet bar group, as described in the previous embodiment. To improve the installation reliability of the magnet bar groups during rotor rotation, a protective sleeve 3 is provided on the outermost rotor core component 102. Setting the magnet poles 2 as permanent magnet segments of different widths can reduce cogging torque.

[0055] Example 3

[0056] In this embodiment, such as Figure 11 and Figure 12 As shown, each group of magnetic steel strips includes five magnetic steel strips 201. The magnetic pole 2 is arranged radially as three permanent magnet segments, each permanent magnet segment constituting one group of magnetic steel strips. Adjacent groups of magnetic steel strips are bonded together. For the three groups of magnetic steel strips constituting the magnetic pole 2, the width of the multiple groups of magnetic steel strips gradually increases from the outer edge of the rotor core 1 towards the center (from the outside to the inside), L6 > L5 > L4. In special cases, L6 > L5 ≥ L4, such as... Figure 12 As shown, the two outer magnetic strip groups have the same width. The arrows in the figure point in the direction from the outside to the inside, that is, from the center of the rotor core 1 to the edge. Figure 13This is an exploded view of the three rotor core segments 102 corresponding to the magnetic pole 2 in this embodiment after installation. Each group of magnetic steel bars is installed in the magnetic pole mounting slot 101 of one rotor core segment 102. The magnetic pole mounting slot 101 of the innermost rotor core segment 102 corresponds to the innermost magnetic steel bar group, and the magnetic pole mounting slot 101 of the middle rotor core segment 102 corresponds to the middle magnetic steel bar group, as detailed in the previous embodiment. To improve the installation reliability of the magnetic steel bar groups during rotor rotation, the outermost rotor core segment 102 is covered with a protective sleeve 3. Setting the magnetic pole 2 as permanent magnet segments of different widths can reduce cogging torque.

[0057] In all the above embodiments, the magnetic poles 2 are bonded to the magnetic pole mounting groove 101. The widths of the different magnetic steel bar groups along the circumference of the rotor core 1 may be the same or different, as determined by those skilled in the art.

[0058] Each magnet group of the rotor pole 2 in Examples 1 to 3 includes five magnetic strips 201 bonded together radially. The difference between the magnet groups in the three examples lies in the different width arrangements of the magnetic poles 2. The wider edge of the magnetic pole 2 has the best effect on reducing cogging torque, followed by the wide middle position, and the widest inner ring position has the least effect. However, all three cases can significantly reduce cogging torque.

[0059] In this invention, the middle portion of the magnetic pole 2 uses a magnetic steel strip 201 with a high magnetization thickness, while the magnetization thickness of the magnetic steel strips 201 on both sides gradually decreases. At this point, the magnetic flux density of the magnetic steel strips 201 constituting the magnetic pole 2 gradually decreases from the center to both sides, thereby increasing the sinusoidal strength of the magnetic field of the magnetic pole 2. For example... Figure 14 As shown, the solid black line is the magnetic flux density waveform of the rotor in the prior art, the dotted dashed line is the magnetic flux density waveform of the rotor of the present invention, and the long dashed line is a sine wave.

[0060] The rotor of the axial flux permanent magnet motor of the present invention optimizes the magnetic poles and reduces the amount of permanent magnets used by splicing together magnetic steel strips 201 of different magnetization directions and thicknesses, and by longitudinally segmenting the magnetic poles 2 and then splicing them together to form the entire magnetic pole 2. Those skilled in the art can select an appropriate number of magnetic steel strips 201 to circumferentially splice into the magnetic steel strip group according to actual needs, making the magnetic flux density waveform more sinusoidal, and selecting an appropriate number of radial segments to reduce cogging torque.

[0061] In the description of this solution, it should be understood that the terms "upper", "lower", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this solution.

[0062] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this solution, "multiple" means two or more, unless otherwise explicitly specified.

[0063] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0064] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rotor for an axial flux permanent magnet motor, characterized in that, Includes a rotor core, wherein a radially arranged magnetic pole mounting groove is provided on the side of the rotor core, and a magnetic pole is disposed in the magnetic pole mounting groove; Each of the magnetic poles includes at least one group of magnetic steel bars, each group of magnetic steel bars being horizontally spliced ​​together from several magnetic steel bars, the length direction of the magnetic steel bars being arranged along the radial direction of the rotor core; The magnetic strip located at the radial center of the magnetic pole has the greatest thickness, and the other magnetic strips are symmetrically arranged on both sides of the radial center of the magnetic pole. The thickness of the magnetic strips gradually decreases from the radial center of the magnetic pole to both sides. The magnetic pole is formed by splicing multiple groups of magnetic steel bars along the radial direction of the rotor core, and the different groups of magnetic steel bars that make up a magnetic pole are bonded together.

2. The rotor of the axial flux permanent magnet motor according to claim 1, characterized in that, The magnetic strip is a rectangular strip, and the horizontal center planes of multiple magnetic strips forming the same magnetic pole coincide.

3. The rotor of the axial flux permanent magnet motor according to claim 1, characterized in that, The longitudinal center planes of the different groups of magnetic steel bars that make up one magnetic pole coincide; The different magnetic bar groups have the same radial length along the rotor core.

4. The rotor of the axial flux permanent magnet motor according to claim 3, characterized in that, The magnetic pole is formed by splicing three groups of magnetic steel bars along the radial direction of the rotor core, and each group of magnetic steel bars is composed of five magnetic steel bars.

5. The rotor of the axial flux permanent magnet motor according to any one of claims 1-4, characterized in that, The rotor core includes several rotor core segments, which are coaxially sleeved together, and the end faces of the multiple rotor core segments are located on the same plane. The magnetic pole mounting slots of adjacent rotor core segments are correspondingly arranged. The inner diameter of the outer rotor core segment is the same as the outer diameter of the adjacent inner rotor core segment; Each rotor core segment has a corresponding magnetic pole mounting slot for installing a set of magnetic steel strips, and the corresponding magnetic steel strip sets of adjacent rotor core segments are bonded together.

6. The rotor of the axial flux permanent magnet motor according to claim 5, characterized in that, A protective sleeve is provided on the outer side of the outermost rotor core segment, and the protective sleeve is interference-fitted to the outer surface of the rotor core.

7. The rotor of the axial flux permanent magnet motor according to claim 1, characterized in that, The magnetic strip is bonded to the magnetic pole mounting groove.

8. The rotor of the axial flux permanent magnet motor according to claim 1, characterized in that, The different magnetic bar groups may have the same or different widths along the circumference of the rotor core.

9. The rotor of the axial flux permanent magnet motor according to claim 1, characterized in that, The rotor core is made of silicon steel strip rolled into shape or soft magnetic powder core integrally formed.

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