Motor rotor

Abstract

The invention, which relates to the technical field of the motor, discloses a motor rotor comprising an iron 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 iron core, each magnetic steel hole group comprises two magnetic steel holes which are formed in the axial end surface of the iron core and are arranged in a penetrating manner, the two magnetic steel holes are arranged at intervals, and the two magnetic steel holes extend in the direction away from each other in the direction that the center of the iron core points to the edge of the iron core; a first interval is formed between the end parts, close to the center of the iron core, of the two corresponding magnetic steel holes; the multiple magnetic isolation holes are formed in the axial end face of the iron core in a penetrating mode, and the multiple magnetic isolation holes are formed in at least one side, in the radial direction of the iron core, of the first interval; each magnetic steel group comprises two pieces of first magnetic steel which are inserted into the two magnetic steel holes in each magnetic steel hole group; according to the technical scheme, the strength of the motor rotor is enhanced, magnetic leakage is reduced, and the motor torque is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor rotor. Background Art

[0002] Rare earth is a strategic reserve material in my country. At the same time, the mining of rare earth permanent magnet materials will also bring a lot of environmental pollution problems. New energy vehicles generally use permanent magnet motors as drive motors. The motor rotors of permanent magnet drive motors generally use rare earth permanent magnet materials such as neodymium iron boron as excitation sources. Therefore, it is very necessary to optimize the rotor structure of permanent magnet drive motors and improve the use efficiency of rare earth permanent magnet materials.

[0003] Existing permanent magnet drive motors generally adopt an embedded magnetic pole structure, with multiple pairs of magnetic steel slots arranged on the motor rotor core, and the magnetic steel is inserted into the magnetic steel slots for excitation. In order to withstand the centrifugal force generated under high-speed rotation, magnetic bridges are generally arranged on both sides of the magnetic steel slots. The thickness of the magnetic bridge is generally large, which can enhance the structural strength, but will cause significant magnetic leakage, seriously affecting the torque output of the motor, requiring the use of more rare earth permanent magnet materials, and the use efficiency of rare earth permanent magnet materials is not high. Therefore, how to increase the strength of the motor rotor while reducing magnetic leakage, improving torque output, and thus improving the use efficiency of rare earth permanent magnet materials has become a technical problem that needs to be solved urgently by people in this field. Summary of the invention

[0004] The main purpose of the present invention is to provide a motor rotor, which aims to increase the strength of the motor rotor while reducing magnetic leakage and improving torque output.

[0005] To achieve the above-mentioned purpose, the motor rotor proposed in the present invention includes an iron 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 along the circumference of the iron core, and each magnetic steel hole group includes two magnetic steel holes arranged on the axial end face of the iron core and penetrating therethrough, the two magnetic steel holes are arranged at intervals, and in the direction from the center of the iron core to the edge of the iron core, the two magnetic steel holes extend away from each other, and a first interval is formed between the ends of the corresponding two magnetic steel holes close to the center of the iron core; the plurality of magnetic isolation holes are arranged on the axial end face of the iron core and penetrating therethrough, and the plurality of magnetic isolation holes are arranged on at least one side of the first interval along the radial direction of the iron core; each magnetic steel group includes two first magnets for being inserted into the two magnetic steel holes in each magnetic steel hole group.

[0006] In one embodiment, the multiple magnetic isolation holes include multiple inner magnetic isolation holes corresponding to the multiple magnetic steel hole groups, each inner magnetic isolation hole is arranged 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 magnetic steel hole group.

[0007] In one embodiment, the hole wall of the inner magnetic isolation hole facing the edge of the iron core is arranged in an arc shape, and the concave surface faces the center of the iron core.

[0008] In one embodiment, a dimension of the second interval along the radial direction of the core is 1-2 mm.

[0009] In one embodiment, the plurality of magnetic isolation holes further include a plurality of outer magnetic isolation holes, and the outer magnetic isolation holes are arranged on a side of the first interval away from the inner magnetic isolation holes.

[0010] In one embodiment, a plurality of outer magnetic isolation holes form a plurality of outer magnetic isolation hole groups, the plurality of outer magnetic isolation hole groups correspond to a plurality of magnetic steel hole groups, each outer magnetic isolation hole group includes two outer magnetic isolation holes, and the two outer magnetic isolation holes extend away from each other in a direction from the center of the iron core to the edge of the iron core.

[0011] In one embodiment, the magnetic steel group further includes a second magnetic steel inserted in the corresponding magnetic isolation holes. In each magnetic steel hole group, the main magnetic flux direction of the second magnetic steel is the same as that of the two first magnetic steels.

[0012] In one embodiment, the second magnetic steel is made of ferrite permanent magnet material or samarium iron nitride permanent magnet material.

[0013] In one embodiment, the iron core includes a plurality of punching sheets stacked along its axial direction, and the plurality of magnetic isolation holes and the plurality of magnetic steel holes all penetrate the plurality of punching sheets.

[0014] In one embodiment, a central hole is provided through the central axis of the iron core; the motor rotor further includes two magnetic isolation plates, a rotating shaft and two retaining rings;

[0015] Two magnetic isolation plates are arranged at two opposite ends of the iron core along its axial direction;

[0016] The rotating shaft passes through the central hole of the iron core and the magnetic isolation plate;

[0017] The two retaining rings are fixedly mounted on the rotating shaft and respectively abut against the end surfaces of the two magnetic isolation plates away from the iron core.

[0018] The technical solution of the present invention is to set a plurality of magnetic steel hole groups through the end face along the axial direction of the iron core. In each magnetic steel hole group, in the direction from the center of the iron core to the edge, the two magnetic steel holes extend in the direction away from each other, and a first interval is formed between the ends of the two magnetic steel holes close to the center of the iron core, and a magnetic isolation hole is set on at least one side of the first interval along the radial direction of the iron core. Thus, the first interval 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 evenly disperse the stress borne by the motor rotor, so that the motor rotor can withstand the centrifugal force at a higher speed. At the same time, the magnetic isolation holes are set, thereby increasing the magnetic resistance of the leakage magnetic circuit to reduce the leakage magnetic of the first magnetic steel in the central magnetic bridge, thereby achieving the effect of enhancing the strength of the motor rotor while reducing the leakage magnetic and improving the motor torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 A cross-sectional view of a first embodiment of a motor rotor provided by the present invention;

[0021] Figure 2 for Figure 1 A partial enlarged view of the middle magnetic steel hole group;

[0022] Figure 3 A cross-sectional view of a second embodiment of a motor rotor provided by the present invention;

[0023] Figure 4 for Figure 3 Schematic diagram of the derivative structure of

[0024] Figure 5 for Figure 3 Schematic diagram of the derivative structure of

[0025] Figure 6 A schematic diagram of the principle of the motor rotor provided by the present invention;

[0026] Figure 7 A cross-sectional view of a third embodiment of a motor rotor provided by the present invention;

[0027] Figure 8 A cross-sectional view of a fourth embodiment of a motor rotor provided by the present invention;

[0028] Fig. 9 This is a schematic diagram of the overall structure of the motor rotor provided by the present invention.

[0029] Description of Figure Numbers:

[0030] 100, motor rotor; 1, rotating shaft; 2, magnetic disk; 21, iron core; 211, punching plate; 22, magnetic steel hole group; 221, magnetic steel hole; 23, first interval; 24, magnetic isolation hole; 241, inner magnetic isolation hole; 242, outer magnetic isolation hole; 25, second interval; 26, third interval; 27, magnetic steel group; 271, first magnetic steel; 272, second magnetic steel; 3, magnetic isolation plate; 4, retaining ring;

[0031] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] In the related art, the permanent magnet drive motor adopts an embedded magnetic pole structure, which can improve the protection of the magnet and reduce the risk of the magnet falling off due to mechanical vibration. The embedded magnetic pole structure is as follows: a plurality of pairs of magnetic steel slots are arranged on the motor rotor core, and the magnets are inserted into the magnetic steel slots one by one. In order to ensure the strength and enable the motor rotor to withstand the centrifugal force generated under high-speed rotation, a spacing is set between the air gaps of each pair of magnetic steel slots close to the center of the core, and the spacing part forms a central magnetic bridge. The existence of the central magnetic bridge can enhance the structural strength, but the excessive thickness of the central magnetic bridge will cause significant magnetic leakage, which seriously affects the torque output of the motor.

[0036] Based on this, the present invention proposes a motor rotor 100 to enhance the strength of the motor rotor 100 while reducing magnetic leakage and improving the motor torque.

[0037] See also Figure 1 , Figure 2 and Fig. 9(The direction of the arrow is the direction of the magnetic pole. Since the magnetic steel is inserted into the groove, the lead line in the figure is the groove when it points to the line, and the lead line is the magnetic steel when it points to the non-line area). In one embodiment of the present invention, the motor rotor 100 includes an iron core 21, a plurality of magnetic steel hole groups 22, a plurality of magnetic isolation holes 24 and a plurality of magnetic steel groups 27; the plurality of magnetic steel hole groups 22 are arranged at intervals along the circumference of the iron core 21, and each magnetic steel hole group 22 includes two magnetic steel holes 221 arranged on the axial end surface of the iron core 21 and penetrating therethrough, and the two magnetic steel holes 221 are arranged at intervals, and In the direction from the center of the iron core 21 to the edge of the iron core 21, the two magnetic steel holes 221 extend in the direction away from each other, and a first gap 23 is formed between the ends of the corresponding two magnetic steel holes 221 close to the center of the iron core 21; a plurality of magnetic isolation holes 24 are arranged on the axial end surface of the iron core 21 and are arranged through it, and the plurality of magnetic isolation holes 24 are arranged on at least one side of the first gap 23 along the radial direction of the iron core 21; each magnetic steel group 27 includes two first magnetic steels 271, which are used to be inserted into the two magnetic steel holes 221 in each magnetic steel hole group 22.

[0038] The technical solution of the present invention is to set a plurality of magnetic steel hole groups 22 through the end surface of the iron core 21 along the axial direction thereof. In each magnetic steel hole group 22, in the direction from the center of the iron core 21 to the edge, two magnetic steel holes 221 extend in a direction away from each other, and a first interval 23 is formed between the ends of the two magnetic steel holes 221 close to the center of the iron core 21, and a magnetic isolation hole 24 is set on at least one side of the first interval 23 along the radial direction of the iron core 21, thereby, the first interval 23 forms a central magnetic bridge, and the plurality of magnetic steel hole groups 22 form a plurality of central magnetic bridges, and the plurality of central magnetic bridges are formed. The core magnetic bridge evenly disperses the stress borne by the motor rotor 100, so that the motor rotor 100 can withstand the centrifugal force at a higher speed. At the same time, a magnetic isolation hole 24 is provided to form an auxiliary magnetic bridge, which increases the leakage magnetic resistance of the central magnetic bridge to reduce the leakage magnetic flux of the first magnetic steel 271 in the central magnetic bridge, thereby enhancing the strength of the motor rotor 100 while reducing the leakage magnetic flux and improving the motor torque. Compared with the existing motor, when providing the same torque, the first magnetic steel 271 requires less material, thereby reducing the material consumption and improving the utilization efficiency of rare earth permanent magnet materials.

[0039] It should be noted that the present invention does not limit the number of magnetic steel hole groups 22 and the spacing distance between the magnetic steel holes 221. The number and spacing distance are selected based on the fact that the application of the magnetic steel hole groups 22 to the motor can achieve a higher output torque of the motor while ensuring the strength of the motor rotor 100. For example, this embodiment has 8 magnetic steel hole groups 22. Accordingly, the shape of the first magnetic steel 271 is not limited. In this embodiment, the first magnetic steel 271 with a rectangular cross section is used.

[0040] The “corresponding two magnetic steel holes 221 ” refer to the two magnetic steel holes 221 in one magnetic steel hole group 22 .

[0041] The "insertion" does not mean directly inserting the first magnetic steel 271 into the magnetic steel hole 221, but requires injection molding or other filling operations to be performed between the first magnetic steel 271 and the magnetic steel hole 221 after insertion to increase the strength of the motor rotor 100. A filling part is formed between the first magnetic steel 271 and the magnetic steel hole 221 by injection molding or other operations, and the pulling effect of the filling part on the first magnetic steel 271 is used to resist the centrifugal force caused by the high-speed operation of the motor rotor 100. At the same time, the shape and size of the first magnetic steel 271 and the magnetic steel hole 221 match each other, so that the first magnetic steel 271 can be stably inserted in the magnetic steel hole 221. The shape of the first magnetic steel 271 can be selected according to needs.

[0042] The "gap" is a physical gap formed between the holes of the iron core 21, and 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 magnetic steel holes 221 close to the center of the iron core 21, and the thickness is 2-3mm.

[0043] Taking the example of a "V"-shaped structure formed by two magnetic steel holes 221 of each magnetic steel hole group 22 with the opening facing the edge of the iron core 21, the "arranged on at least one side of the first interval 23 along the radial direction of the iron core 21" includes the following cases: arranged on the side of the intersection of the "V"-shaped structure (with the first interval 23 as the intersection) close to the opening, or, arranged on the side of the intersection of the "V"-shaped structure away from the opening, or, respectively arranged 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.

[0044] In one embodiment of the present invention, the plurality of magnetic isolation holes 24 include a plurality of inner magnetic isolation holes 241 corresponding to the plurality of magnetic steel hole groups 22, and each inner magnetic isolation hole 241 is arranged on one side of the first interval 23 toward the center of the iron core 21, and a second interval 25 is formed between the inner magnetic isolation hole 241 and the corresponding magnetic steel hole group 22. Taking the "V"-shaped structure as an example, the inner magnetic isolation hole 241 is arranged on the side of the intersection of the "V"-shaped structure away from the opening, forming an approximate "V" structure, and the magnetic pole direction is as shown in the figure, and the second interval 25 is located on one side of the line connecting the two magnetic pole surfaces of the first magnetic steel 271, the magnetic flux is small, and the magnetic circuit of the first magnetic steel 271 passes through the inner magnetic isolation hole 24. The inner magnetic isolation hole 24 has little interference with the overall magnetic circuit of the motor rotor 100, and 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, can reduce the leakage magnetic flux of the first magnetic steel 271 at the central magnetic bridge, and minimize its interference with the overall magnetic circuit while reducing the leakage magnetic flux.

[0045] See also Figure 2In one embodiment of the present invention, the hole wall of the inner magnetic isolation hole 241 facing the edge of the iron core 21 is arranged in an arc shape, and the concave surface of the arc faces the center of the iron core 21. In this way, the arc-shaped hole wall makes the stress distribution at the second interval 25 of the motor rotor 100 more uniform when the motor rotor 100 rotates at a high speed, and the second interval portion corresponds to the magnetic steel group 27, so that it is distributed circumferentially along the iron core 21. At a single second interval 25, the arc-shaped arrangement can make the stress distribution on the second interval 25 more uniform. The circumferential arrangement of multiple second intervals 25 can evenly disperse the stress borne by the motor rotor 100, and evenly distribute the stress borne by the motor rotor 100 to each point of each second interval 25, thereby greatly enhancing the strength of the motor rotor 100.

[0046] In addition, a plurality of reinforcing ribs may be protruded from the arc-shaped hole wall of the inner magnetic isolation hole 241, and the reinforcing ribs extend in an arc shape along the arc-shaped hole wall. The mechanical strength of the magnetic steel slot can be enhanced, deformation caused by vibration or temperature change can be reduced, and the magnetic flux can be guided to flow along the expected path, thereby reducing magnetic flux leakage and improving the magnetic performance of the motor. At the same time, a second magnetic steel 272 may be inserted into the arc-shaped hole wall, and the reinforcing ribs may help fix the second magnetic steel 272 and reduce the risk of displacement of the second magnetic steel 272.

[0047] Furthermore, the dimensions of the multiple magnetic steel holes 221 along the radial direction of the iron core 21 are greater than the dimensions of the first magnetic steel 271 along the radial direction of the iron core 21, thereby forming a cavity, i.e., an air gap, between the first magnetic steel 271 and the magnetic steel holes 221 at both ends of the radial direction of the iron core 21. The magnetic isolation hole 24 is matched with the shape of the air gap formed by its corresponding two magnetic steel holes 221, so that the second interval 25 is arranged in an arc shape, and the concave surface of the arc faces the center of the iron core 21 to more evenly disperse the stress.

[0048] Further, the second interval center line ( Figure 2 The catenary shape (shown by the dashed line) is in a standard catenary shape, and its curvature radius is the largest near the edge of the iron core 21. In this way, the catenary shape has a better effect of evenly dispersing stress.

[0049] It is easy to imagine that the shape of the inner magnetic isolation hole 241 is not limited to the above shape. Under the condition of meeting the strength requirement, the cross-sectional shape of the inner magnetic isolation hole 241 can be set to a reverse tile shape (with the positive direction toward the center of the iron core 21), a rectangle or a trapezoid or other shapes.

[0050] The thickness of the second spacer 25 also affects the strength and magnetic flux leakage of the motor rotor 100. If the thickness is too large, the magnetic flux leakage reduction is not obvious and the effect is not significant; if the thickness is insufficient, the strength of the motor rotor 100 is difficult to ensure. In one embodiment of the present invention, the size of the second spacer 25 along the radial direction of the iron core 21 is 1-2 mm. Such a size setting can just achieve the highest strength of the motor rotor 100 while taking into account the good effect of reducing magnetic flux leakage. Due to the existence of the second spacer 25, the thickness of the first spacer 23 can be appropriately increased to enhance the strength performance of the motor rotor 100.

[0051] The “dimension of the second spacer 25 along the radial direction of the core 21 ” refers to the thickness of the second spacer 25 .

[0052] See also Figure 7 In one embodiment of the present invention, the plurality of magnetic isolation holes 24 further include a plurality of outer magnetic isolation holes 242, and the outer magnetic isolation holes 242 are arranged on a side of the first spacer 23 away from the inner magnetic isolation holes 241. Such an arrangement can further reduce magnetic leakage.

[0053] Each magnetic steel hole group 22 may correspond to one or more outer magnetic isolation holes 242. When each magnetic steel 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 arranged relative to the first interval 23, and a third interval 26 is formed between the outer magnetic isolation hole 242 and the magnetic steel group 27. The hole wall of the outer magnetic isolation hole 242 facing the edge of the iron core 21 is arranged in an arc shape, and the concave surface of the arc faces the center of the iron core 21. In this way, at a single magnetic isolation hole 24, the arc-shaped arrangement 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 electric core, so that multiple third intervals 26 evenly disperse the stress on the motor rotor 100, and evenly distribute the stress on the motor rotor 100 to each point of each third interval 26, which greatly enhances the strength of the motor rotor 100. Preferably, the center line of the third interval 26 is in a standard catenary shape, and its curvature radius is the largest near the edge of the iron core 21.

[0054] It is easy to imagine that the shape of the outer magnetic isolation hole 242 is not limited to the above shape. Under the condition of meeting 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, rectangle or trapezoid.

[0055] See also Figure 8In another embodiment of the present invention, each magnetic steel hole group 22 corresponds to two outer magnetic isolation holes 242, and multiple outer magnetic isolation holes 242 form multiple outer magnetic isolation hole groups. Multiple outer magnetic isolation hole groups correspond to multiple magnetic steel hole groups 22, and 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 the edge of the iron core 21, the two outer magnetic isolation holes 242 extend in a direction away from each other. In this way, the magnetic steel hole group 22 and the corresponding outer magnetic isolation hole group form a double "V" structure arranged along the radial direction of the iron core 21, so that the motor rotor 100 has a greater torque while meeting the strength requirements, which helps to optimize the magnetic circuit, reduce magnetic resistance, and improve the utilization rate of magnetic flux, thereby reducing the use of magnetic steel, reducing costs while maintaining good performance.

[0056] It should be noted that the above-mentioned double "V"-shaped structure includes a first "V"-shaped structure formed by two magnetic steel holes 221 in a magnetic steel hole group 22 and a second "V"-shaped structure formed by an outer magnetic hole group. The openings of the two "V"-shaped structures are both facing the edge of the iron core 21 and are arranged axially along the iron core 21.

[0057] See also Figure 1 In one embodiment of the present invention, the magnetic steel group 27 further includes a second magnetic steel 272 inserted into the corresponding magnetic isolation hole 24. In each magnetic steel hole group 22, the second magnetic steel 272 has the same main magnetic flux direction as the two first magnetic steels 271. In this way, the second magnetic steel 272 can generate a certain magnetic flux, which is closed through the second interval 25 and / or the third interval 26, so that the auxiliary magnetic bridge is further saturated, the leakage magnetic flux of the first magnetic steel 271 is suppressed, and the leakage magnetic flux of the motor rotor 100 through the central magnetic bridge is significantly reduced, which increases the magnetic flux of the first magnetic steel 271, so that the torque of the motor is significantly increased under the same current.

[0058] Taking the inner magnetic steel group 27 as an example, assuming that the magnetic pole directions of the two first magnetic steels 271 in the magnetic steel group 27 are as follows: Figure 2 As shown (the direction of the arrow represents the direction of the magnetic pole), the main magnetic flux direction of the two first magnetic steels 271 is from the center of the iron core 21 toward the edge of the iron core 21, and the main magnetic flux direction of the second magnetic steel 272 is the same as the two first magnetic steels 271, and therefore points to the edge of the iron core 21, and the magnetic pole direction B of the second magnetic steel is shown in the figure.

[0059] Specifically, the second magnetic steel 272 is inserted into the corresponding outer magnetic isolation hole 242 and / or inner magnetic isolation hole 241 to form a tile shape.

[0060] See also Figure 6 , Figure 6A comparison diagram of the magnetic circuits before and after adding the magnetic isolation hole 24 and the second magnetic steel 272 is provided. The leakage magnetic circuit and the magnetic circuit of the second magnetic steel 272 are shown in the figure. Before adding, the leakage magnetic circuit C of the first magnetic steel is as shown in the figure, and part of the magnetic circuit forms a leakage magnetic circuit along the central magnetic bridge, which cannot generate effective torque; after adding, the leakage magnetic circuit of the first magnetic steel (the closed figure at the end of the first magnetic steel 271) and the second magnetic steel magnetic circuit (the closed figure at the end of the second magnetic steel 272) are shown in the figure. Under the action of the second magnetic steel 272, part of the leakage magnetic circuit is eliminated, the leakage magnetic is reduced, and the effective torque of the motor rotor 100 is improved.

[0061] It should be noted that in order to ensure the strength of the motor rotor 100, after the second magnetic steel 272 is inserted into the magnetic isolation hole 24, it is necessary to fill the space between the second magnetic steel 272 and the magnetic isolation hole 24 to form a filling part. The specific method of filling is: forming a gap between the second magnetic steel 272 and the magnetic isolation hole 24, and filling the molten filling part into the gap. In 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.

[0062] See also Figures 3 to 5 In another embodiment of the present invention, under the condition of satisfying strength, the cross-sectional shape of the second magnetic steel 272 can be set to an inverted tile shape (with the direction toward the center of the core 21 as the positive direction), a rectangle or a trapezoid or other shapes. When the cross-sectional shape of the second magnetic steel 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 magnetic steel 272 and the magnetic isolation hole 24; when the second magnetic steel 272 with a rectangular cross-sectional shape is selected, it is easy to manufacture and assemble, and the cost is low; when the second magnetic steel 272 with a trapezoidal cross-sectional shape is selected, the design of the trapezoidal magnetic steel can better guide the magnetic flux to flow along a predetermined path, reduce magnetic flux leakage, and thus improve the efficiency of the motor.

[0063] Specifically, when the second magnetic steel 272 is inserted into the magnetic isolation hole 24 , the size of the magnetic isolation hole 24 along the circumferential direction of the core 21 is larger than the size of the second magnetic steel 272 , so as to form an air gap between the inner wall of the magnetic isolation hole 24 and the second magnetic steel 272 .

[0064] In one embodiment of the present invention, the material of the second magnetic steel 272 is ferrite permanent magnet material or samarium iron nitride permanent magnet material. Ferrite permanent magnet material has higher stability, does not contain rare earth materials, is inexpensive, and will not significantly affect the cost of the motor rotor 100. Sm-iron nitrogen permanent magnet material uses less rare earth elements, reducing dependence on rare earth resources.

[0065] In one embodiment of the present invention, the iron core 21 includes a plurality of punching sheets 211 stacked along its axial direction, and a plurality of magnetic isolation holes 24 and a plurality of magnetic steel holes 221 all penetrate the plurality of punching sheets 211. In this way, the stacking of the plurality of punching sheets 211 increases the mechanical strength of the motor rotor 100, which helps to resist the centrifugal force during high-speed rotation. The punching sheets 211 are thin metal sheets manufactured by a stamping process.

[0066] Specifically, multiple iron cores 21 are stacked along the axial direction thereof, and multiple iron cores 21 and multiple magnetic steel groups 27 form a magnetic cake 2. With such a configuration, the magnetic steel and the iron cores 21 are reasonably arranged, a uniform magnetic field can be generated, the magnetic flux density can be increased, the magnetic flux density distribution can be optimized, and the output power and efficiency of the motor can be improved; at the same time, the mechanical strength of the rotor can be improved, and deformation and vibration during high-speed rotation can be reduced; the overall weight can be reduced while ensuring the performance of the motor; it helps to position and fix the magnetic steel group 27, and simplifies the assembly process.

[0067] Furthermore, the magnetic steel holes 221 and / or magnetic isolation holes 24 in each iron core 21 form a hole segment, and each hole segment is staggered along the axial direction of the iron core 21. Such an 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 helps to improve the stability of the magnetic steel, especially at high-speed rotation, helping to reduce the risk of the magnetic steel falling off due to mechanical vibration.

[0068] Specifically, the motor rotor 100 further includes a weight-reducing hole, which is arranged along the axial direction of the punching sheet 211. Such an arrangement can effectively reduce the weight of the punching sheet 211, reduce the proportion of the punching sheet 211 in the entire motor, make the motor rotor 100 lightweight, improve the working efficiency of the motor, and save material costs.

[0069] See also Fig. 9 In one embodiment of the present invention, a center hole is provided through the center axis of the iron core 21; the motor rotor 100 further includes two magnetic isolation plates 3, a rotating shaft 1 and two retaining rings 4; the two magnetic isolation plates 3 are provided at two opposite ends of the iron core 21 along its axial direction; the rotating shaft 1 passes through the center hole of the iron core 21 and the magnetic isolation plates 3; the two retaining rings 4 are fixedly mounted on the rotating shaft 1, and respectively abut against the end faces of the two magnetic isolation plates 3 away from the iron core 21. In this arrangement, the magnetic steel group 27 is isolated by the magnetic isolation plates 3 to prevent magnetic flux leakage and increase magnetic flux density, thereby optimizing the magnetic circuit and improving motor efficiency, and the retaining rings 4 abut against the magnetic isolation plates 3 to press the punching sheets 211 from both ends to prevent the punching sheets 211 from axially moving along the rotating shaft 1.

[0070] Specifically, the magnetic isolation plate 3 is assembled on the rotating shaft 1 by interference fit or clearance fit; the retaining ring 4 is fixed on the rotating shaft 1 by interference fit, welding or bolt locking. Interference fit refers to a small amount of interference between the magnetic isolation plate 3 and the rotating shaft 1, so that the magnetic isolation plate 3 is fastened to the rotating shaft 1, which can increase the contact area between the magnetic isolation plate 3 and the rotating shaft 1, improve the mechanical strength and rigidity of the motor rotor 100, and also help to reduce vibration during high-speed rotation and improve the stability of the motor operation; clearance fit refers to a certain gap between the magnetic isolation plate 3 and the rotating shaft 1, which can reduce the friction between the magnetic isolation plate 3 and the rotating shaft 1, help to reduce wear, make the assembly process easier, and complete the assembly without applying a lot of force, and allow a certain amount of thermal expansion space between the magnetic isolation plate 3 and the rotating shaft 1, which helps to avoid stress caused by temperature changes.

[0071] Furthermore, one or more radial protrusions are provided on the central hole of the rotor punching 211. During the assembly process, the radial protrusions can be used as positioning references to ensure that the rotor punching 211 is correctly aligned with the rotating shaft 1.

[0072] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A motor rotor, characterized in that: include: Iron core, A plurality of magnetic steel hole groups are arranged at intervals along the circumference of the core, each magnetic steel hole group includes two magnetic steel holes arranged on the axial end surface of the core and penetrating the core, the two magnetic steel holes are arranged at intervals, and in the direction from the center of the core to the edge of the core, the two magnetic steel holes extend away from each other, and a first interval is formed between the ends of the two corresponding magnetic steel holes close to the center of the core; A plurality of magnetic isolation holes are arranged on the axial end surface of the iron core and are arranged through the iron core, and the plurality of magnetic isolation holes are arranged on at least one side of the first interval along the radial direction of the iron core; and A plurality of magnetic steel groups, each of which includes two first magnetic steels for being inserted into the two magnetic steel holes in each of the magnetic steel hole groups.

2. The motor rotor according to claim 1, characterized in that: The multiple magnetic isolation holes include multiple inner magnetic isolation holes corresponding to the multiple magnetic steel hole groups, each of the inner magnetic isolation holes is arranged on the side of the first interval facing the center of the iron core, and a second interval is formed between each of the inner magnetic isolation holes and the corresponding magnetic steel hole group.

3. The motor rotor according to claim 2, characterized in that: The hole wall of the inner magnetic isolation hole facing the edge of the iron core is arranged in an arc shape, and the concave surface faces the center of the iron core.

4. The motor rotor according to claim 2, characterized in that: A dimension of the second interval along the radial direction of the core is 1-2 mm.

5. The motor rotor according to claim 2, characterized in that: The plurality of magnetic isolation holes further include a plurality of outer magnetic isolation holes, and the outer magnetic isolation holes are arranged on a side of the first interval away from the inner magnetic isolation holes.

6. The motor rotor according to claim 5, characterized in that: The multiple outer magnetic isolation holes form a multiple outer magnetic isolation hole groups, and the multiple outer magnetic isolation hole groups correspond to the multiple 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 according to any one of claims 1 to 6, characterized in that: The magnetic steel group further includes a second magnetic steel inserted into the corresponding magnetic isolation hole. In each magnetic steel hole group, the main magnetic flux direction of the second magnetic steel is the same as that of the two first magnetic steels.

8. The motor rotor according to claim 7, characterized in that: The material of the second magnetic steel is ferrite permanent magnet material or samarium iron nitride permanent magnet material.

9. The motor rotor according to claim 7, characterized in that: The iron core includes a plurality of punching sheets stacked along its axial direction, and the plurality of magnetic isolation holes and the plurality of magnetic steel holes all penetrate the plurality of punching sheets.

10. The motor rotor according to claim 1, characterized in that: A center hole is provided through the center axis of the iron core; The motor rotor also includes: Two magnetic isolation plates are arranged at two opposite ends of the iron core along its axial direction; A rotating shaft passes through the central hole and the magnetic isolation plate; and Two retaining rings are fixedly mounted on the rotating shaft and respectively abut against the end surfaces of the two magnetic isolation plates away from the iron core.

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