Motor rotor

Abstract

The present application discloses a motor rotor. The motor rotor comprises a core, a plurality of magnetic steel hole groups, a plurality of magnetic isolation holes, and a plurality of magnetic steel groups. The plurality of magnetic steel hole groups are arranged at intervals in the circumferential direction of the core, each magnetic steel hole group comprises two magnetic steel holes arranged on the axial end surface of the core and passing through the core, the two magnetic steel holes are spaced apart from each other, in a direction from the center of the core toward the edge of the core, the two magnetic steel holes extend away from each other, and a first gap is formed between the end portions of corresponding two magnetic steel holes close to the center of the core. The plurality of magnetic isolation holes are arranged on the axial end surface of the core and pass through the core, and the plurality of magnetic isolation holes are arranged on at least one side of the first gaps in the radial direction of the core. Each magnetic steel group comprises two first magnetic steels used for being inserted into the two magnetic steel holes in each magnetic steel hole group.

Description

motor rotor

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202411192345.1, filed on August 28, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of motor technology, and in particular to a motor rotor. Background Technology

[0004] Rare earth elements are strategic reserves for my country, but the mining of rare earth permanent magnet materials also causes significant environmental pollution. New energy vehicles generally use permanent magnet motors as drive motors, and the rotors of these motors typically use rare earth permanent magnet materials such as neodymium iron boron as the excitation source. Therefore, optimizing the rotor structure of permanent magnet drive motors and improving the efficiency of rare earth permanent magnet materials is essential.

[0005] Existing permanent magnet drive motors generally employ an embedded magnetic pole structure, with multiple pairs of magnetic slots on the rotor core. Magnets are inserted into these slots for excitation. To withstand the centrifugal force generated during high-speed rotation, magnetic bridges are typically installed on both sides of the magnetic slots. These bridges are generally quite thick, which strengthens the structure but causes significant magnetic leakage, severely impacting the motor's torque output. This necessitates the use of large quantities of rare-earth permanent magnet materials, which have low utilization efficiency. Therefore, how to increase the motor rotor strength while reducing magnetic leakage and improving torque output, thereby enhancing the utilization efficiency of rare-earth permanent magnet materials, has become a pressing technical problem for researchers in this field. Summary of the Invention

[0006] The main objective of this application is to propose a motor rotor that aims to increase the strength of the motor rotor while reducing leakage flux and improving torque output.

[0007] To achieve the above objectives, the motor rotor proposed in this application includes an iron core, multiple sets of magnet holes, multiple magnetic isolation holes, and multiple sets of magnets; the multiple sets of magnet holes are arranged circumferentially along the iron core, each set of magnet holes includes two magnet holes disposed on the axial end face of the iron core and extending through it, the two magnet holes are spaced apart, and in the direction from the center of the iron core to the edge of the iron core, the two magnet holes extend away from each other, and a first gap is formed between the ends of the corresponding two magnet holes near the center of the iron core; the multiple magnetic isolation holes are disposed on the axial end face of the iron core and extending through it, and the multiple magnetic isolation holes are disposed on at least one side of the first gap along the radial direction of the iron core; each set of magnets includes two first magnets for insertion into the two magnet holes in each set of magnet holes.

[0008] In one embodiment, the plurality of magnetic isolation holes include a plurality of inner magnetic isolation holes corresponding to a plurality of magnet hole groups. Each inner magnetic isolation hole is disposed on the side of the first interval facing the center of the iron core, and a second interval is formed between each inner magnetic isolation hole and its corresponding magnet hole group.

[0009] In one embodiment, the inner magnetic isolation hole has an arc-shaped hole wall facing the edge of the iron core, with the concave surface facing the center of the iron core.

[0010] In one embodiment, the second gap has a dimension of 1-2 mm in the radial direction of the iron core.

[0011] In one embodiment, the plurality of magnetic isolation holes further includes a plurality of outer magnetic isolation holes, which are disposed on the side of the first interval opposite to the inner magnetic isolation holes.

[0012] In one embodiment, multiple outer magnetic isolation holes form multiple outer magnetic isolation hole groups, which correspond to multiple magnetic steel hole groups. Each outer magnetic isolation hole group includes two outer magnetic isolation holes, which extend away from each other in the direction from the center of the iron core to the edge of the iron core.

[0013] In one embodiment, the magnet assembly further includes a second magnet inserted into a corresponding magnetic isolation hole, wherein in each magnet hole assembly, the main magnetic flux direction of the second magnet is the same as that of the two first magnets.

[0014] In one embodiment, the second magnet is made of ferrite permanent magnet material or samarium iron nitride permanent magnet material.

[0015] In one embodiment, the core includes a plurality of laminations stacked along its axial direction, with a plurality of magnetic isolation holes and a plurality of magnet holes passing through the plurality of laminations.

[0016] In one embodiment, a central hole is provided through the central axis of the iron core; the motor rotor also includes two magnetic shielding plates, a rotating shaft, and two retaining rings;

[0017] Two magnetic shielding plates are located at opposite ends of the iron core along its axial direction;

[0018] The shaft passes through the central hole of the iron core and the magnetic shielding plate;

[0019] Two retaining rings are fixedly installed on the rotating shaft, and respectively abut against the end faces of the two magnetic shielding plates away from the iron core.

[0020] The technical solution of this application involves a plurality of magnetic steel hole groups permeating the end face of the iron core along its axial direction. In each magnetic steel hole group, two magnetic steel holes extend away from each other in the direction from the center of the iron core to the edge. A first gap is formed between the ends of the two magnetic steel holes near the center of the iron core. A magnetic isolation hole is provided on at least one side of the first gap along the radial direction of the iron core. Thus, the first gap forms a central magnetic bridge, and the plurality of magnetic steel hole groups form a plurality of central magnetic bridges. The plurality of central magnetic bridges uniformly distribute the stress borne by the motor rotor, so that the motor rotor can withstand the centrifugal force at higher speeds. At the same time, the magnetic isolation hole increases the magnetic resistance of the leakage magnetic circuit, thereby reducing the leakage magnetic flux of the first magnet in the central magnetic bridge. This achieves the effect of enhancing the strength of the motor rotor while reducing leakage magnetic flux and increasing the motor torque. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 is a cross-sectional view of an embodiment of the motor rotor provided in this application;

[0023] Figure 2 is a partial enlarged view of the magnetic hole group in Figure 1;

[0024] Figure 3 is a cross-sectional view of another embodiment of the motor rotor provided in this application;

[0025] Figure 4 is a schematic diagram of the derived structure of Figure 3;

[0026] Figure 5 is a schematic diagram of the derived structure of Figure 3;

[0027] Figure 6 is a schematic diagram of the motor rotor provided in this application;

[0028] Figure 7 is a cross-sectional view of another embodiment of the motor rotor provided in this application;

[0029] Figure 8 is a cross-sectional view of another embodiment of the motor rotor provided in this application;

[0030] Figure 9 is a schematic diagram of the overall structure of the motor rotor provided in this application.

[0031] Explanation of icon numbers:

[0032] 100. Motor rotor; 1. Shaft; 2. Magnetic disc; 21. Iron core; 211. Lamination; 22. Magnet hole assembly; 221. Magnet hole; 23. First spacer; 24. Magnetic isolation hole; 241. Inner magnetic isolation hole; 242. Outer magnetic isolation hole; 25. Second spacer; 26. Third spacer; 27. Magnet assembly; 271. First magnet; 272. Second magnet; 3. Magnetic isolation plate; 4. Retaining ring;

[0033] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Embodiments of the present invention

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0036] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0037] In related technologies, permanent magnet drive motors employ an embedded magnetic pole structure, which improves the protection of the magnets and reduces the risk of magnets falling off due to mechanical vibration. The embedded magnetic pole structure is as follows: multiple pairs of magnetic slots are provided on the motor rotor core, and magnets are inserted into each slot. To ensure strength and enable the motor rotor to withstand the centrifugal force generated under high-speed rotation, a gap is set between the air gaps near the center of each pair of magnetic slots. This gap forms a central magnetic bridge. The presence of the central magnetic bridge strengthens the structure; however, excessive thickness of the central magnetic bridge can cause significant magnetic leakage, severely affecting the motor's torque output.

[0038] Based on this, this application proposes a motor rotor 100 to enhance the strength of the motor rotor 100 while reducing leakage flux and increasing motor torque.

[0039] Please refer to Figures 1, 2, and 9 (where the arrows indicate the magnetic pole direction; since the magnets are inserted into the grooves, the lines in the figures point to the grooves when they are on the lines and to the magnets when they are on the non-line areas). In one embodiment of this application, the motor rotor 100 includes an iron core 21, multiple magnet hole groups 22, multiple magnetic isolation holes 24, and multiple magnet groups 27. The multiple magnet hole groups 22 are arranged circumferentially around the iron core 21. Each magnet hole group 22 includes two magnet holes 221 disposed on the axial end face of the iron core 21 and passing through it. The two magnet holes 221 are spaced apart. The two magnetic holes 221 are spaced apart and extend away from each other in the direction from the center of the iron core 21 to the edge of the iron core 21. A first gap 23 is formed between the ends of the two corresponding magnetic holes 221 near the center of the iron core 21. A plurality of magnetic isolation holes 24 are disposed on the end face of the iron core 21 in its axial direction and are disposed through it. The plurality of magnetic isolation holes 24 are disposed on at least one side of the first gap 23 along the radial direction of the iron core 21. Each magnetic group 27 includes two first magnets 271 for insertion into the two magnetic holes 221 in each magnetic hole group 22.

[0040] The technical solution of this application involves a plurality of magnetic steel hole groups 22 extending through the end face of the iron core 21 along its axial direction. In each magnetic steel hole group 22, two magnetic steel holes 221 extend away from each other in the direction from the center of the iron core 21 to the edge. A first gap 23 is formed between the ends of the two magnetic steel holes 221 near the center of the iron core 21, and a magnetic isolation hole 24 is provided on at least one side of the first gap 23 along the radial direction of the iron core 21. Thus, the first gap 23 forms a central magnetic bridge, and the plurality of magnetic steel hole groups 22 form a plurality of central magnetic bridges. The magnetic bridge evenly distributes the stress on the motor rotor 100, enabling the motor rotor 100 to withstand centrifugal force at higher speeds. At the same time, the magnetic isolation hole 24 is provided to form an auxiliary magnetic bridge, which increases the leakage magnetic resistance of the central magnetic bridge, thereby reducing the leakage magnetic flux of the first magnet 271 in the central magnetic bridge. This enhances the strength of the motor rotor 100 while reducing leakage magnetic flux and increasing the motor torque. Compared with existing motors, less material is required for the first magnet 271 to provide the same torque, thereby reducing material usage and improving the utilization efficiency of rare earth permanent magnet materials.

[0041] This application does not limit the number of magnet hole groups 22 or the spacing between magnet holes 221. The selection of their number and spacing is based on the principle that their application in the motor can achieve a high output torque while ensuring the strength of the motor rotor 100 itself. For example, this embodiment has 8 magnet hole groups 22. Correspondingly, the shape of the first magnet 271 is not limited. In this embodiment, a first magnet 271 with a rectangular cross-section is used.

[0042] The "corresponding two magnet holes 221" refers to the two magnet holes 221 in a magnet hole group 22.

[0043] The "insertion" does not involve directly placing the first magnet 271 into the magnet hole 221. Instead, after insertion, injection molding or other filling operations are performed between the first magnet 271 and the magnet hole 221 to increase the strength of the motor rotor 100. This injection molding or other operation forms a filling portion between the first magnet 271 and the magnet hole 221. The pulling force of this filling portion on the first magnet 271 counteracts the centrifugal force generated by the high-speed rotation of the motor rotor 100. Simultaneously, the shape and size of the first magnet 271 and the magnet hole 221 are matched to ensure that the first magnet 271 is stably inserted into the magnet hole 221. The shape of the first magnet 271 can be selected as needed.

[0044] The “gap” is a physical gap formed between holes in the iron core 21. Its shape and thickness are related to the shape and spacing of the two holes. The thickness of the first gap 23 is related to the distance between the ends of the corresponding two magnet holes 221 near the center of the iron core 21, and the thickness is 2-3 mm.

[0045] Taking the two magnet holes 221 of each magnet hole group 22 forming a "V"-shaped structure with the opening facing the edge of the iron core 21 as an example, the "set on at least one side of the first interval 23 along the radial direction of the iron core 21" includes the following situations: set on the side of the intersection of the "V"-shaped structure (with the first interval 23 as the intersection point) close to the opening, or set on the side of the intersection of the "V"-shaped structure away from the opening, or set on the side of the intersection of the "V"-shaped structure close to the opening and the side of the intersection of the "V"-shaped structure away from the opening, respectively.

[0046] In one embodiment of this application, the plurality of magnetic isolation holes 24 include a plurality of inner magnetic isolation holes 241 corresponding to a plurality of magnet hole groups 22. Each inner magnetic isolation hole 241 is disposed on the side of the first interval 23 facing the center of the iron core 21, forming a second interval 25 between the inner magnetic isolation hole 241 and its corresponding magnet hole group 22. Taking a "V" shaped structure as an example, the inner magnetic isolation hole 241 is disposed on the side away from the opening at the intersection of the "V" shaped structure, forming an approximate "V" structure. As shown in the figure, the magnetic pole direction is as follows. The second interval 25 is located on one side of the line connecting the two magnetic pole surfaces of the first magnet 271. The magnetic flux is small, and the magnetic circuit of the first magnet 271 passes through the inner magnetic isolation hole 24 less. The inner magnetic isolation hole 24 has little interference with the overall magnetic circuit of the motor rotor 100. At the same time, an auxiliary magnetic bridge is formed at the second interval 25, which increases the magnetic resistance of the leakage magnetic circuit and can reduce the leakage magnetic flux of the first magnet 271 at the central magnetic bridge. While reducing the leakage magnetic flux, its interference with the overall magnetic circuit is minimized.

[0047] Referring to Figure 2, in one embodiment of this application, the inner magnetic isolation hole 241 has an arc-shaped hole wall facing the edge of the iron core 21, with the concave surface of the arc facing the center of the iron core 21. This arc-shaped hole wall design allows for a more uniform stress distribution at the second interval 25 when the motor rotor 100 rotates at high speed. The second interval portion corresponds to the magnet assembly 27, thus distributing the stress circumferentially along the iron core 21. At a single second interval 25, the arc shape ensures a more uniform stress distribution. Multiple circumferentially arranged second intervals 25 can evenly disperse the stress borne by the motor rotor 100, distributing the stress evenly to every point of each second interval 25, greatly enhancing the strength of the motor rotor 100.

[0048] Furthermore, multiple reinforcing ribs can be protruding within the arc-shaped wall of the inner magnetic isolation hole 241, extending in an arc shape along the hole wall. This enhances the mechanical strength of the magnet slot, reduces deformation caused by vibration or temperature changes, guides magnetic flux to flow along the expected path, reduces magnetic flux leakage, and improves the magnetic performance of the motor. Simultaneously, a second magnet 272 can be inserted within the arc-shaped hole wall; the reinforcing ribs help secure the second magnet 272, reducing the risk of displacement.

[0049] In one embodiment, the dimensions of the plurality of magnet holes 221 along the radial direction of the iron core 21 are larger than the dimensions of the first magnet 271 along the radial direction of the iron core 21, thereby forming cavities, i.e. air gaps, at both ends of the first magnet 271 along the radial direction of the iron core 21 with the magnet holes 221. The shape of the magnetic isolation hole 24 matches the air gap formed by its corresponding two magnet holes 221, so that the second interval 25 is arc-shaped, with the concave surface of the arc facing the center of the iron core 21, so as to distribute stress more evenly.

[0050] In one embodiment, the second interval centerline (shown as a dashed line in Figure 2) is a standard catenary shape, with its radius of curvature being largest near the edge of the core 21. This arrangement provides a better effect of uniformly distributing stress.

[0051] The shape of the inner magnetic isolation hole 241 is not limited to the above shape. Under the condition of meeting the strength requirements, the cross-sectional shape of the inner magnetic isolation hole 241 can be set to other shapes such as reverse tile shape (with the direction towards the center of the iron core 21 as the positive direction), rectangle, or trapezoid.

[0052] The thickness of the second interval 25 also affects the strength and magnetic leakage of the motor rotor 100. If the thickness is too large, the reduction in magnetic leakage is not significant, and the effect is not remarkable; if the thickness is insufficient, the strength of the motor rotor 100 cannot be guaranteed. In one embodiment of this application, the dimension of the second interval 25 along the radial direction of the iron core 21 is 1-2 mm. This dimension setting is just right to achieve the maximum strength of the motor rotor 100 while also ensuring a good reduction in magnetic leakage. Due to the presence of the second interval 25, the thickness of the first interval 23 can be appropriately increased to enhance the strength performance of the motor rotor 100.

[0053] The "dimension of the second interval 25 along the radial direction of the iron core 21" is the thickness of the second interval 25.

[0054] Referring to Figure 7, in one embodiment of this application, the plurality of magnetic isolation holes 24 further includes a plurality of outer magnetic isolation holes 242, which are disposed on the side of the first interval 23 opposite to the inner magnetic isolation holes 241. This arrangement can further reduce magnetic leakage.

[0055] Each magnet hole group 22 can correspond to one or more outer magnetic isolation holes 242. When each magnet hole group 22 corresponds to one outer magnetic isolation hole 242, the outer magnetic isolation hole 242 and the inner magnetic isolation hole 241 are set relative to the first interval 23, forming a third interval 26 between the outer magnetic isolation hole 242 and the magnet group 27. The hole wall of the outer magnetic isolation hole 242 facing the edge of the iron core 21 is arc-shaped, and the concave surface of the arc faces the center of the iron core 21. With this arrangement, at a single magnetic isolation hole 24, the arc shape can make the stress distribution on the third interval 26 more uniform. Multiple outer magnetic isolation holes 242 are arranged along the circumference of the core so that multiple third intervals 26 can evenly distribute the stress on the motor rotor 100, and evenly distribute the stress on the motor rotor 100 to every point of each third interval 26, greatly enhancing the strength of the motor rotor 100. Preferably, the center line of the third interval 26 is a standard catenary shape, and its radius of curvature is the largest near the edge of the iron core 21.

[0056] The shape of the outer magnetic isolation hole 242 is not limited to the above shape. Under the condition of satisfying the strength of the motor rotor 100, the cross-sectional shape of the magnetic isolation hole 24 can be set to other shapes such as reverse tile shape, rectangle or trapezoid.

[0057] Referring to Figure 8, in another embodiment of this application, each magnet hole group 22 corresponds to two outer magnetic isolation holes 242. Multiple outer magnetic isolation holes 242 form multiple outer magnetic isolation hole groups, which correspond to multiple magnet hole groups 22. Each outer magnetic isolation hole group includes two outer magnetic isolation holes 242. In the direction from the center of the iron core 21 to its edge, the two outer magnetic isolation holes 242 extend in a direction away from each other. This arrangement creates a double "V"-shaped structure where the magnet hole groups 22 and their corresponding outer magnetic isolation hole groups are arranged radially along the iron core 21. This allows the motor rotor 100 to have greater torque while meeting strength requirements, helps optimize the magnetic circuit, reduces magnetic resistance, and improves the utilization rate of magnetic flux, thereby reducing the amount of magnets used, lowering costs while maintaining good performance.

[0058] The aforementioned double "V" structure includes a first "V" structure formed by two magnet holes 221 in a magnet hole group 22 and a second "V" structure formed by an external magnetic isolation hole group. The openings of both "V" structures face the edge of the iron core 21 and are arranged along the axial direction of the iron core 21.

[0059] Referring to Figure 1, in one embodiment of this application, the magnet assembly 27 further includes a second magnet 272 inserted into a corresponding magnetic isolation hole 24. In each magnet hole assembly 22, the main magnetic flux direction of the second magnet 272 is the same as that of the two first magnets 271. With this configuration, the second magnet 272 can generate a certain magnetic flux, forming a closed loop through the second interval 25 and / or the third interval 26, further saturating the auxiliary magnetic bridge, suppressing the leakage flux of the first magnet 271, significantly reducing the leakage flux of the motor rotor 100 through the central magnetic bridge, increasing the magnetic flux of the first magnet 271, and thus significantly increasing the motor torque under the same current.

[0060] Taking the inner magnet group 27 as an example, assuming that the magnetic pole directions of the two first magnets 271 in the magnet group 27 are as shown in Figure 2 (the direction of the arrow represents the magnetic pole direction), the main magnetic flux direction of the two first magnets 271 is from the center of the iron core 21 toward the edge of the iron core 21, while the main magnetic flux direction of the second magnet 272 is the same as that of the two first magnets 271, so it points to the edge of the iron core 21. The magnetic pole direction B of the second magnet is shown in the figure.

[0061] The second magnet 272 is inserted into the corresponding outer magnetic isolation hole 242 and / or inner magnetic isolation hole 241, forming a tile shape.

[0062] Please refer to Figure 6, which is a comparison diagram of the magnetic circuit before and after adding the magnetic isolation hole 24 and the second magnet 272. The leakage magnetic circuit and the magnetic circuit of the second magnet 272 are shown in the figure. Before the addition, the leakage magnetic circuit C of the first magnet is shown in the figure. Part of the magnetic circuit forms a leakage magnetic circuit along the central magnetic bridge, which cannot generate effective torque. After the addition, the leakage magnetic circuit of the first magnet (the closed shape at the end of the first magnet 271) and the magnetic circuit of the second magnet (the closed shape at the end of the second magnet 272) are shown in the figure. Under the action of the second magnet 272, part of the leakage magnetic circuit is eliminated, leakage magnetic flux is reduced, and the effective torque of the motor rotor 100 is improved.

[0063] To ensure the strength of the motor rotor 100, after the second magnet 272 is inserted into the magnetic isolation hole 24, it is necessary to fill the space between the second magnet 272 and the magnetic isolation hole 24 to form a filling part. The specific filling method is as follows: a gap is formed between the second magnet 272 and the magnetic isolation hole 24, and the molten filling part is filled into the gap. During this process, it is necessary to ensure that the filling part has good fluidity during the melting process so that the filling part can fill the gap.

[0064] Referring to Figures 3 to 5, in another embodiment of this application, under the condition of satisfying the strength requirements, the cross-sectional shape of the second magnet 272 can be set as an inverted tile shape (with the direction towards the center of the iron core 21 as the positive direction), a rectangle, a trapezoid, or other shapes. When the cross-sectional shape of the second magnet 272 is an inverted tile shape, the magnetic flux can be more evenly distributed on the entire circumference of the motor rotor 100 by adjusting the curvature of the second magnet 272 and the magnetic isolation hole 24. When a rectangular cross-section second magnet 272 is used, it is easy to manufacture and assemble, and the cost is low. When a trapezoidal cross-section second magnet 272 is used, the design of the trapezoidal magnet can better guide the magnetic flux to flow along a predetermined path, reduce magnetic flux leakage, and thus improve the efficiency of the motor.

[0065] When the second magnet 272 is inserted into the magnetic isolation hole 24, the size of the magnetic isolation hole 24 along the circumference of the iron core 21 is larger than the size of the second magnet 272, so as to form an air gap between the inner wall of the magnetic isolation hole 24 and the second magnet 272.

[0066] In one embodiment of this application, the second magnet 272 is made of ferrite permanent magnet or samarium iron nitride permanent magnet. Ferrite permanent magnet has higher stability, does not contain rare earth materials, and is inexpensive, so it will not significantly affect the cost of the motor rotor 100. Samarium iron nitride permanent magnet uses fewer rare earth elements, reducing dependence on rare earth resources.

[0067] In one embodiment of this application, the iron core 21 includes a plurality of laminations 211 stacked along its axial direction, with a plurality of magnetic isolation holes 24 and a plurality of magnet holes 221 penetrating the laminations 211. This arrangement, with the multiple laminations 211 stacked together, increases the mechanical strength of the motor rotor 100, helping to resist centrifugal force during high-speed rotation. The laminations 211 are thin metal sheets manufactured using a stamping process.

[0068] Multiple iron cores 21 are stacked along their axial direction, forming a magnetic disc 2 with multiple magnet assemblies 27. This arrangement, with its rational layout of magnets and iron cores 21, can generate a uniform magnetic field, increase magnetic flux density, optimize magnetic flux density distribution, and improve the output power and efficiency of the motor. Simultaneously, it enhances the mechanical strength of the rotor, reducing deformation and vibration during high-speed rotation. It also reduces the overall weight while ensuring motor performance and facilitates the positioning and fixation of the magnet assemblies 27, simplifying the assembly process.

[0069] In one embodiment, the magnet holes 221 and / or magnetic isolation holes 24 in each core 21 form a segment, and each segment is staggered along the axial direction of the core 21. This arrangement helps to optimize the magnetic flux density distribution, making the magnetic flux density more uniform, thereby improving the efficiency and smoothness of the motor, and also helps to improve the stability of the magnets, especially at high speeds, helping to reduce the risk of magnets falling off due to mechanical vibration.

[0070] The motor rotor 100 also includes weight-reduction holes, which are arranged through the lamination 211 along its axial direction. This arrangement can effectively reduce the weight of the lamination 211, reduce the proportion of the lamination 211 in the overall motor weight, make the motor rotor 100 lightweight, improve motor efficiency, and save material costs.

[0071] Referring to Figure 9, in one embodiment of this application, a central hole is provided through the central axis of the iron core 21; the motor rotor 100 also includes two magnetic shielding plates 3, a rotating shaft 1, and two retaining rings 4; the two magnetic shielding plates 3 are located at opposite ends of the iron core 21 along its axial direction; the rotating shaft 1 passes through the central hole of the iron core 21 and the magnetic shielding plates 3; the two retaining rings 4 are fixedly installed on the rotating shaft 1 and respectively abut against the end faces of the two magnetic shielding plates 3 away from the iron core 21. This arrangement isolates the magnet assembly 27 through the magnetic shielding plates 3, preventing magnetic flux leakage, increasing magnetic flux density, thereby optimizing the magnetic circuit and improving motor efficiency. Furthermore, the retaining rings 4 abut against the magnetic shielding plates 3, pressing the laminations 211 from both ends to prevent the laminations 211 from moving axially along the rotating shaft 1.

[0072] The magnetic shielding plate 3 is assembled onto the rotating shaft 1 by interference fit or clearance fit; the retaining ring 4 is fixed onto the rotating shaft 1 by interference fit, welding, or bolt locking. An interference fit means that there is a small amount of interference between the magnetic shielding plate 3 and the rotating shaft 1, which secures the magnetic shielding plate 3 to the rotating shaft 1. This increases the contact area between the magnetic shielding plate 3 and the rotating shaft 1, improving the mechanical strength and rigidity of the motor rotor 100, and also helps reduce vibration during high-speed rotation, thus improving the stability of motor operation. A clearance fit means that there is a certain gap between the magnetic shielding plate 3 and the rotating shaft 1, which reduces friction between them, helps reduce wear, makes the assembly process easier, and allows for assembly without applying a large force. It also allows for a certain amount of thermal expansion space between the magnetic shielding plate 3 and the rotating shaft 1, helping to avoid stress caused by temperature changes.

[0073] In one embodiment, one or more radial protrusions are provided in the center hole of the rotor lamination 211. During assembly, the radial protrusions can serve as positioning references to ensure that the rotor lamination 211 is correctly aligned with the shaft 1.

[0074] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. An electric motor rotor, wherein, The motor rotor includes: Iron core, Multiple groups of magnetic steel holes are arranged at intervals along the circumference of the iron core. Each group of magnetic steel holes includes two magnetic steel holes disposed on the end face of the iron core in its axial direction and passing through it. The two magnetic steel holes are spaced apart and extend away from each other in the direction from the center of the iron core to the edge of the iron core. A first interval is formed between the ends of the corresponding two magnetic steel holes near the center of the iron core. Multiple magnetic isolation holes are disposed on the end face of the iron core in its axial direction and are disposed through the iron core. The multiple magnetic isolation holes are disposed on at least one side of the first interval along the radial direction of the iron core. Multiple magnet groups, each magnet group including two first magnets for insertion into the two magnet holes in each magnet hole group.

2. The motor rotor as described in claim 1, wherein, The plurality of magnetic isolation holes include a plurality of inner magnetic isolation holes corresponding to the plurality of magnet hole groups. Each inner magnetic isolation hole is disposed on the side of the first interval facing the center of the iron core, and a second interval is formed between each inner magnetic isolation hole and its corresponding magnet hole group.

3. The motor rotor as described in claim 2, wherein, The inner magnetic isolation hole has an arc-shaped hole wall facing the edge of the iron core, with the concave surface facing the center of the iron core.

4. The motor rotor as described in claim 2, wherein, The second interval has a dimension of 1-2 mm along the radial direction of the iron core.

5. The motor rotor as described in claim 2, wherein, The plurality of magnetic isolation holes also include a plurality of outer magnetic isolation holes, which are disposed on the side of the first interval opposite to the inner magnetic isolation holes.

6. The motor rotor as described in claim 5, wherein, The plurality of outer magnetic isolation holes form a plurality of outer magnetic isolation hole groups, which correspond to the plurality of magnetic steel hole groups. Each outer magnetic isolation hole group includes two outer magnetic isolation holes. In the direction from the center of the iron core to the edge of the iron core, the two outer magnetic isolation holes extend in a direction away from each other.

7. The motor rotor as described in any one of claims 1 to 6, wherein, The magnet assembly also includes a second magnet inserted into the corresponding magnetic isolation hole. In each magnet hole assembly, the main magnetic flux direction of the second magnet is the same as that of the two first magnets.

8. The motor rotor as described in claim 7, wherein, The second magnet is made of ferrite permanent magnet material or samarium iron nitrogen permanent magnet material.

9. The motor rotor as described in claim 7, wherein, The iron core includes multiple laminations stacked along its axial direction, and the multiple magnetic isolation holes and the multiple magnet holes all penetrate the multiple laminations.

10. The motor rotor as claimed in claim 1, wherein, A central hole is provided through the central axis of the iron core; The motor rotor also includes: Two magnetic shielding plates are disposed at opposite ends of the iron core along its axial direction; The rotating shaft passes through the central hole and the magnetic shielding plate; Two retaining rings are fixedly installed on the rotating shaft and abut against the end faces of the two magnetic shielding plates away from the iron core, respectively.

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