A permanent magnet motor

Abstract

The present invention relates to the field of permanent magnet motors and discloses a permanent magnet motor comprising a housing, a stator core, a rotor core, and permanent magnets. The rotor core comprises at least two fully continuous bridge lamination stacks and at least one semi-continuous bridge lamination stack, wherein the laminations in the fully continuous bridge lamination stacks include a plurality of fully continuous bridge punches that are all connected to a first central connecting bridge and distributed circumferentially, and the laminations in the semi-continuous bridge lamination stacks include at least one separated punch that is disconnected from a second central connecting bridge and distributed circumferentially. The fully continuous bridge lamination stacks and the semi-continuous bridge lamination stacks are axially stacked, with each semi-continuous bridge lamination stack located between two fully continuous bridge lamination stacks, so that adjacent sectors within the same laminated layer of the fully continuous bridge lamination stack are asymmetrical, and the permanent magnets are placed in the slots between adjacent sectors. The present invention can simplify the motor production process and improve the structural strength of the motor.

Description

[0001] This application is a divisional application with the application date of "2018.11.30", application number "201811459944.X", and application name "A built-in permanent magnet motor". Technical Field

[0002] The present invention relates to the field of permanent magnet motors, and in particular to a permanent magnet motor. Background Art

[0003] Traditional brushless DC motors use surface-mounted magnetic tiles or internal radially magnetized steel structures, resulting in low power density. Due to cost constraints, a tangentially magnetized parallel magnetic circuit structure is used to increase the magnetic flux per pole. However, this existing tangentially magnetized structure still suffers from high magnetic flux leakage, limiting motor performance improvements.

[0004] The existing rotor core has at least one tooth sector disconnected from the rotor ring, while at least one tooth sector is connected to the sleeve. This suppresses near-axial magnetic flux leakage. This rotor core sleeve is equipped with positioning protrusions to position and support the permanent magnets. Analysis reveals that this design lacks axial support for the disconnected rotor tooth sectors, resulting in poor axial structural strength and unsuitable for large-scale production. Furthermore, the positioning protrusions used to support and position the permanent magnets generate self-linkage magnetic flux leakage, reducing motor power density and hindering performance.

[0005] On the other hand, due to the increase in power density, the stator core of the built-in tangential magnetized motor is easily saturated, resulting in high core loss and reduced motor efficiency. At the same time, the enhanced electromagnetic force wave leads to increased vibration noise. The existing technology suppresses vibration noise by methods such as slanted poles and slanted slots. The corresponding methods increase the difficulty of the manufacturing process and increase production hours. For example, a stator core with a bar-shaped curved circle is designed. The teeth extend inward from the stator annular yoke, and a wire groove is formed between two adjacent stator teeth. The stator magnetic circuit is balanced, the magnetic flux is moderately averaged, local saturation is reduced, the process is simple, and the production efficiency is high. However, the above patent only relies on parameters such as the stator slot width, tooth width and yoke width to average the magnetic flux, and fails to consider the influence of the stator shape and structure on the motor magnetic field, loss, etc. It is not suitable for high power density motor structures. It also does not consider reducing the motor vibration noise by combining the stator core and the casing, and does not provide a structure that can comprehensively consider the power density and suppress vibration and reduce noise.

[0006] Therefore, there is an urgent need for a permanent magnet brushless DC motor with simple process, reliable structure, high power density, low vibration and noise that can be suitable for large-scale production. Summary of the Invention

[0007] In order to overcome the deficiencies in the prior art, the present invention aims to provide a permanent magnet motor that can simplify the production process while improving the structural strength and power density.

[0008] In order to solve the above technical problems of the present invention, the present invention provides a permanent magnet motor, comprising a casing, a stator core, a rotor core and permanent magnets; the stator core is arranged circumferentially along the inner wall of the casing, and the rotor core is installed in the space surrounded by the stator core; the rotor core comprises at least two full-bridge lamination groups and at least one half-bridge lamination group, wherein the laminations in the full-bridge lamination group include a plurality of full-bridge punchings connected to the first center connecting bridge and the first center connecting bridge and distributed along the circumferential direction, and the laminations in the half-bridge lamination group are connected to the first center connecting bridge and the first center connecting bridge. The laminations include a second central connecting bridge and at least one separate punching sheet that is disconnected from the second central connecting bridge and distributed circumferentially, and the full-bridge lamination group and the half-bridge lamination group are stacked axially so that each half-bridge lamination group is located between two full-bridge lamination groups, so that adjacent sectors within the same lamination layer of the full-bridge lamination group are asymmetric, and the permanent magnets are placed in the slots between adjacent sectors; the contact points between the stator core and the casing form a contact domain, and the gaps where the stator core and the casing are not in contact form a filling domain by injecting filling material.

[0009] Preferably, the fully connected bridge lamination group includes multiple fully connected bridge laminations, and adjacent fully connected bridge laminations are overlapped and stacked; the semi-connected bridge lamination group includes multiple semi-connected bridge laminations, and adjacent semi-connected bridge laminations are overlapped and stacked.

[0010] Preferably, the stator core includes a plurality of T-shaped tooth yokes, and each of the T-shaped tooth yokes is enclosed along the inner wall of the casing.

[0011] Preferably, the number of the T-tooth yokes is , so that the outer boundary of the stator core is a regular dodecagon; the outer surface of each T-tooth yoke is parallel to the bottom of the stator slot, the boundary surface between the tooth part and the yoke part of the T-tooth yoke is perpendicular, and the number of T-tooth yokes is equal to the number of motor slots.

[0012] Preferably, each of the T-shaped tooth yokes is provided with two inner and outer rivet points of different sizes, and the diameter of the outer rivet point is larger than the diameter of the inner rivet point; the outer rivet point is arranged at the center position of the yoke, and the inner rivet point is arranged in the middle of the tooth crown of the tooth portion; the tooth crown of the tooth portion is in the shape of an oblique shoulder type, and the angle between the inner inclined surface of the oblique shoulder type tooth crown groove and the radial boundary of the tooth portion is an obtuse angle.

[0013] Preferably, the fully-connected bridge-type laminations include a plurality of fully-connected bridge punchings, and a support bridge is provided between adjacent fully-connected bridge punchings; among two adjacent fully-connected bridge punchings, one protrudes radially outward to form a wide magnetic bridge, and the other protrudes radially outward to form a narrow magnetic bridge, and the width of the wide magnetic bridge is greater than the width of the narrow magnetic bridge.

[0014] Preferably, the semi-connected bridge type laminations include a plurality of semi-connected bridge punches and a plurality of separation punches, a separation punch is provided between two adjacent semi-connected bridge punches, and the separation punch does not contact the semi-connected bridge punches; there is a partition type support bridge between adjacent semi-connected bridge punches; the semi-connected bridge punches have a narrow magnetic bridge, and a partition type wide magnetic bridge is provided on the second center connecting bridge, and the width of the partition type wide magnetic bridge is greater than the width of the narrow magnetic bridge.

[0015] Preferably, in at least one laminated layer of the semi-bridge type lamination stack, the second central connecting bridge extends radially outward to form the narrow magnetic bridge.

[0016] Preferably, the polarities of two adjacent permanent magnets are different.

[0017] Preferably, adjacent sectors within the same laminated layer of the semi-connected bridge-type lamination group are asymmetric, the permanent magnets are placed in the slots between adjacent sectors, the polarities of the permanent magnets in two adjacent slots are different, and the corresponding second center connecting bridges in the slots extend radially outward to form a radial slot bottom protrusion; the supporting bridge contacts the permanent magnet and overlaps with the radial slot bottom protrusion axially; the widths of the supporting bridge and the radial slot bottom protrusion on the sleeve side are equal; the radial slot bottom protrusion is separated from the permanent magnet, and the distance between the outermost side of the radial slot bottom protrusion and the permanent magnet is greater than 0.5 mm.

[0018] Preferably, the outer arc surface of each of the fully connected bridge punching sheets includes multiple sections of splines for reducing torque fluctuations;

[0019] The spline at least includes a circular arc segment main spline and straight line segment splines arranged on both sides of the circular arc segment main spline.

[0020] Preferably, the splines include a main arc segment spline, arc segment splines arranged on both sides of the main arc segment spline, and straight line segment splines arranged outside the two arc segment splines.

[0021] Preferably, the outer arc surface of each of the semi-bridge punching sheets and each of the separation punching sheets includes multiple sections of splines for reducing torque fluctuations;

[0022] The spline at least includes a circular arc segment main spline and straight line segment splines arranged on both sides of the circular arc segment main spline.

[0023] Preferably, the splines include a main arc segment spline, arc segment splines arranged on both sides of the main arc segment spline, and straight line segment splines arranged outside the two arc segment splines.

[0024] Preferably, the ratio of the number of fully connected bridge laminations in a fully connected bridge lamination group to the number of half-connected bridge laminations in a half-connected bridge lamination group is less than 0.5.

[0025] Preferably, the number of segments x of the spline satisfies:

[0026] If LCM(2P, S) / 2P is an odd number, then x=[LCM(2P, S) / 2P];

[0027] If LCM(2P, S) / 2P is an even number, then x=[LCM(2P, S) / 2P]-1;

[0028] Among them, x, LCM, P, and S are the number of spline segments, the least common multiple, the number of pole pairs, and the number of slots, respectively.

[0029] Preferably, assuming that the central angle of the main spline of the arc segment is α, and the central angles of the remaining splines are βi, then:

[0030]

[0031] This invention simplifies the motor production process and improves its structural strength. By designing a partitioned support bridge and a partitioned wide magnetic bridge, the motor rotor's structural strength is significantly enhanced. Furthermore, the semi-connected bridge laminations ensure that at least half of each rotor core lamination is connected to the sleeve, facilitating positioning during large-scale production.

[0032] The present invention significantly reduces self-linkage magnetic flux leakage at the bottom of the rotor slots, thereby increasing the air gap flux. The T-tooth yoke stator structure reduces motor saturation and maximizes the flux per pole. A comparison of the back EMF coefficient of the motor structure of the present invention with that of a conventional full-bridge motor structure shows a significant improvement. When the motor is running under heavy load, the torque-current curve exhibits excellent linearity and avoids saturation, thereby improving motor performance.

[0033] The five-segment spline rotor structure reduces back-EMF harmonic distortion and enhances the sinusoidality of the air-gap magnetic field, thereby reducing tangential torque pulsation and radial vibration. Furthermore, a T-shaped tooth yoke structure with a filler region between the stator and the housing reduces vibration transmission between the stator and the housing, ultimately reducing vibration and noise.

[0034] Reducing the self-linkage leakage flux at the bottom of the rotor slots and thus increasing the power density can ensure the high sinusoidality of the air gap magnetic field and significantly improve the back electromotive force coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural diagram of an embodiment of the present invention;

[0036] Figure 2 is a schematic structural diagram of a rotor core in one embodiment of the present invention;

[0037] Figure 3 1 is a schematic structural diagram of a T-shaped tooth yoke according to an embodiment of the present invention;

[0038] Figure 4 1 is a schematic diagram of the structure of a stator assembly in one embodiment of the present invention;

[0039] Figure 5 1 is a schematic structural diagram of a semi-connected bridge-type lamination according to an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the structure of a fully connected bridge-type lamination in one embodiment of the present invention;

[0041] FIG7( a ) is a diagram showing the self-linkage leakage magnetic field distribution of the slot bottom of a full-bridge-connected rotor in the prior art;

[0042] FIG7( b ) is a partial enlarged view of the portion circled in FIG7( a );

[0043] FIG8( a ) is a diagram showing the self-linkage magnetic flux leakage distribution at the bottom of a slot of a bridge-type rotor without partition support in the prior art;

[0044] FIG8( b ) is a partial enlarged view of the portion circled in FIG8( a );

[0045] FIG9( a ) is a diagram showing the self-linkage magnetic flux leakage distribution at the bottom of the slot of the partition support bridge rotor of the present invention;

[0046] FIG9( b ) is a partial enlarged view of the portion circled in FIG9( a );

[0047] Figure 10 This is a comparison curve of the self-linkage leakage coefficient at the bottom of the slot near the axis of three motors with different structures;

[0048] Figure 11 Schematic diagram of the space inside the stator slot of a regular polygonal T-shaped tooth yoke according to one embodiment of the present invention;

[0049] Figure 12 This is a schematic diagram of the space inside the stator slot of the traditional structure;

[0050] Figure 13 Schematic diagram of the distribution of the splines of each segment of a five-segment spline rotor punching in one embodiment of the present invention;

[0051] Figure 14 is the no-load back EMF harmonic content of an embodiment of the present invention;

[0052] Figure 15 is a schematic diagram of the exploded structure of the rotor core in one embodiment of the present invention;

[0053] Figure 16 Schematic diagram of the structure of a semi-connected bridge-type lamination stack in one embodiment of the present invention.

[0054] Description of Reference Numerals

[0055] Housing 1;

[0056] stator core 2; contact area 22; filling area 23;

[0057] T-shaped tooth yoke 21; yoke portion 211; stator slot bottom 2111; bending point 2112; tooth portion 212; oblique shoulder tooth crown slot 2121; outer rivet point 213; inner rivet point 214;

[0058] Rotor core 3;

[0059] Fully connected bridge lamination set 31; fully connected bridge punching 311; outer arc surface 3111; plastic-coated through hole 3112; rivet point 3113; first central connecting bridge H1; support bridge 312; wide magnetic bridge 313; narrow magnetic bridge 314;

[0060] Semi-connected bridge lamination set 32; semi-connected bridge punch 321; outer arc surface 3211 of semi-connected bridge punch; plastic-coated through hole 3212 of semi-connected bridge punch; rivet point 3213 of semi-connected bridge punch; separation punch 322; outer arc surface 3221 of separation punch; plastic-coated through hole 3222 of separation punch; rivet point 3223 of separation punch; second center connecting bridge H2; partition support bridge 323; partition wide magnetic bridge 324; narrow magnetic bridge 325;

[0061] Permanent magnet 4; shaft 5; winding 6; insulating frame 7. DETAILED DESCRIPTION

[0062] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0063] It should be noted in advance that, in the description of this application, “axial direction” generally refers to the axial direction of the motor, that is, the extending direction along the rotation axis of the motor.

[0064] like Figure 1 、 Figure 5 and Figure 6As shown, one embodiment of the present invention is a permanent magnet brushless DC motor, which includes a housing 1, a stator core 2, a rotor core 3, a permanent magnet 4, a shaft 5, a winding 6 and an insulating frame 7. The stator core 2 is arranged circumferentially along the inner wall of the casing 1, and the rotor core 3 is installed in the space surrounded by the stator core 2; the rotor core 3 includes at least two full-bridge lamination groups 31 and at least one half-bridge lamination group 32, wherein the laminations in the full-bridge lamination group 31 include multiple full-bridge punchings 311 that are connected to the first central connecting bridge H1 and distributed along the circumferential direction, and the laminations in the half-bridge lamination group 32 include at least one separated punching 322 that is disconnected from the second central connecting bridge H2 and distributed along the circumferential direction, and the full-bridge lamination group 31 and the half-bridge lamination group 32 are stacked axially so that each half-bridge lamination group 32 is located between two full-bridge lamination groups 31, so that adjacent sectors in the same lamination layer of the full-bridge lamination group 31 are asymmetric, and permanent magnets 4 are placed in the slots between adjacent sectors, and the polarities of two adjacent permanent magnets 4 are different, forming a built-in permanent magnet motor. Adjacent sectors within the same laminated layer of the semi-connected bridge-type lamination group 32 are asymmetric, and permanent magnets 4 are placed in the slots between adjacent sectors. The polarities of the permanent magnets 4 in two adjacent slots are different, and the corresponding semi-connected bridge punchings 321 in the slots extend radially outward to form radial slot bottom protrusions. The radial slot bottom protrusions are separated from the permanent magnets 4, and the distance between the outermost side of the radial slot bottom protrusions and the permanent magnets 4 is greater than 0.5 mm.

[0065] like Figure 15 and 16 As shown, the full-bridge lamination group 31 includes multiple full-bridge laminations, and adjacent full-bridge laminations are overlapped and stacked; the half-bridge lamination group 32 includes multiple half-bridge laminations, and adjacent half-bridge laminations are overlapped and stacked.

[0066] like Figure 3 and 4 As shown, the stator core 2 is enclosed by twelve T-shaped tooth yokes 21. The stator core 2 and the housing 1 are connected at the connection points between adjacent T-shaped tooth yokes 21, forming a contact region 22. The outer surface or top surface of the yoke portion 211 of each T-shaped tooth yoke 21 is flat, and the gap between it and the inner wall of the circular housing 1 forms a filling region 23. Filling region 23 can be filled with a variety of materials. In this example, the housing 1 is made of bulk molding compound, so the bulk molding compound is also injected into filling region 23. That is, the housing 1 and the filling material are made of the same material. The mixture of the two enhances the motor's stiffness, improves damping, and absorbs vibration. The winding 6 uses flying fork winding. The designed stator slot pattern effectively avoids flying fork winding interference, improving mass production efficiency.

[0067] like Figure 3As shown, the outer surface of the yoke 211 of the T-shaped tooth yoke 21 is parallel to the stator slot bottom 2111. The T-shaped tooth yoke 21 is provided with two inner and outer rivet points of different sizes. The size of the outer rivet point 213 is larger than the size of the inner rivet point 214. In this embodiment, the diameter of the outer rivet point 213 is 1.2 mm, and the diameter of the inner rivet point 214 is 1.0 mm. The outer rivet point 213 is located at the center of the yoke 211, and the inner rivet point 214 is located at the crown of the tooth portion 212. Middle part; The tooth crown shape of the tooth portion 212 is an oblique shoulder type, and the angle between the inner inclined surface of the oblique shoulder tooth crown groove 2121 and the radial boundary of the tooth portion 212 is an obtuse angle, preferably 120°, and the tooth portion 212 is perpendicular to the outer surface of the yoke portion 211 or the stator slot bottom 2111, and the slope of the straight line segment of the oblique shoulder tooth crown groove 2121 is 30°, the width of the narrowest part of the tooth portion 212 is 5.2mm, and the height of the yoke portion 211 is 3.5mm. Combined with the production process calculation, in this embodiment, Figure 11 As shown, the theoretical slot area of ​​the stator core 2 is compared with Figure 12 The slot area of ​​the conventional circular stator core punching sheet shown is increased by 8.5%. The bending point 2112 mainly serves to release stress when bending the stator core 2.

[0068] like Figure 2 、 15 As shown in Figure 16, in this embodiment, the rotor core 3 includes two fully connected bridge-type lamination groups 31 and one half-connected bridge-type lamination group 32, which are stacked axially so that the half-connected bridge-type lamination group 32 is located between the two fully connected bridge-type lamination groups 31, that is, the two fully connected bridge-type lamination groups 31 are respectively located at both ends of the rotor core 3, and the half-connected bridge-type lamination group 32 is located in the middle of the rotor core 3. This rotor core structure can make adjacent sectors asymmetric, thereby greatly reducing the self-linkage leakage flux at the bottom of the permanent magnet slot near the axis, so as to improve the power density.

[0069] The semi-bridge type lamination stack 32 is composed of Figure 5 The multiple semi-connected bridge laminations shown are stacked and formed, and the semi-connected bridge laminations include multiple semi-connected bridge punches 321 and multiple separation punches 322. A separation punch 322 is provided between two adjacent semi-connected bridge punches 321, and the separation punch 322 does not contact the semi-connected bridge punch 321; a plurality of semi-connected bridge punches 321 are provided with a partition type support bridge 323 between each two; the semi-connected bridge punches 321 have a narrow magnetic bridge 325, and a partition type wide magnetic bridge 324 is provided on the second center connecting bridge H2, and the width of the partition type wide magnetic bridge 324 is greater than the width of the narrow magnetic bridge 325.

[0070] The full bridge type lamination group 31 is composed of Figure 6The fully connected bridge-type laminations shown are stacked and formed, and the fully connected bridge-type laminations include a plurality of fully connected bridge punchings 311 with support bridges 312 between adjacent ones; one of the two adjacent fully connected bridge punchings 311 protrudes radially outward to form a wide magnetic bridge 313, and the other protrudes radially outward to form a narrow magnetic bridge 314, and the width of the wide magnetic bridge 313 is greater than the width of the narrow magnetic bridge 314. The fully connected bridge-type laminations are axially opened with a plastic-coated through-hole 3112, and the semi-connected bridge-type laminations are axially opened with a plastic-coated through-hole 3212. Plastic material is used to pass through the plastic-coated through-holes 3112 and 3212 to wrap and reinforce the rotor core 3. The rivet points 3113, 3213, and 3223 are used for positioning connection. The distance between the edge of the through hole of the punching sheet and the boundary of the adjacent permanent magnet slot is 2.6 mm. The axial stacking structure is A+B+A. The ratio of the number of fully connected bridge laminations in a fully connected bridge lamination group 31 to the number of half-connected bridge laminations in a half-connected bridge lamination group 32 is less than 0.5. For example, a group of fully connected bridge laminations 31 includes 10 fully connected bridge laminations, and a group of half-connected bridge laminations 32 includes 30 half-connected bridge laminations. Compared with a motor whose rotor is entirely formed by half-connected bridge laminations, the back electromotive force coefficient of the motor in this embodiment is increased by 34.4%.

[0071] like Figure 6 As shown, the fully connected bridge lamination structure comprises ten fully connected bridge punchings 311, all connected together by a first central connecting bridge H1. This first central connecting bridge H1 comprises multiple support bridges 312, multiple wide magnetic bridges 313, and multiple narrow magnetic bridges 314, forming a continuous, integral whole. In this embodiment, the permanent magnet 4 is 5 mm thick, the narrow magnetic bridges 314 are 0.8 mm wide, the wide magnetic bridges 313 are 1.5 mm wide, the magnetic bridge length is 2.8 mm, and the support bridges 312 are 1.2 mm wide. The support bridges 312 contact the permanent magnet 4 and axially overlap with the radial groove bottom protrusions. The widths of the support bridges 312 and the radial groove bottom protrusions on the sleeve side are equal.

[0072] like Figure 5As shown, the semi-connected bridge lamination is a semi-connected bridge structure, in which the five separated punches 322 included therein are all disconnected from the second center connection bridge H2, that is, the five separated punches 322 are not connected to the second center connection bridge H2, and are in a separated state from the second center connection bridge H2. The second center connection bridge H2 includes a plurality of partitioned support bridges 323, a plurality of partitioned wide magnetic bridges 324 and a plurality of narrow magnetic bridges 325. The second center connection bridge H2 is a continuous whole. Of course, the number of separated punches 322 is not limited to 5, and can be 1-4, or other numbers. The narrow magnetic bridge 325 has a width of 0.8 mm, and the distance between the partitioned support bridge 323 and the permanent magnet 4 is 2.5 mm. Through the optimization of the above parameters, the self-linkage leakage magnetic flux at the bottom of the permanent magnet slot near the axis of the rotor core 3 is greatly reduced, ensuring that other parameters remain unchanged. The magnetic field distributions of the full-bridge connected rotor structure, the non-partitioned support bridge structure and the present embodiment are compared, and the self-linkage leakage magnetic flux coefficient is calculated, see. Figure 10 It can be obtained that the slot bottom self-linkage leakage coefficients of the three types of motors, namely A full-connected bridge type, B non-partition support bridge type and C hybrid bridge type of the present invention, are 0.207, 0.065 and 0.018 respectively, which proves that this embodiment can greatly reduce the slot bottom self-linkage leakage coefficient, thereby greatly improving the power density of the motor.

[0073] like Figure 5 、 Figure 6 and Figure 13 As shown, the outer arc surface of both the full-bridge lamination and the semi-bridge lamination adopts a five-segment spline structure to reduce torque fluctuation and improve motor vibration noise. Each rotor sector adopts this structure, namely, a middle arc segment main spline D with a central angle of α concentric with the stator, two eccentric arc line splines E with a central angle of β1 adjacent to the arc segment main spline D on the left and right, and two straight line segment splines F with a central angle of β2 on the edge, which should satisfy α+2β1+2β2=36°.

[0074] By comparing and analyzing the full-circle rotor, the traditional three-segment arc rotor and the five-segment spline rotor of this embodiment, the optimized no-load back EMF distortion rate is only 1.18%, and the corresponding harmonic components are as follows: Figure 14 In this embodiment, the rotor surface is overmolded with bulk molding compound, and the maximum speed at which the motor fails structurally is 19,000 rpm, which is more than six times the actual operating speed of the motor. This demonstrates that the rotor surface structure design of this embodiment can ensure high sinusoidality of the air gap magnetic field and sufficient structural strength.

[0075] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0076] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0077] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A permanent magnet motor comprising a housing, a stator core, a rotor core, and a permanent magnet; the rotor core is mounted in a space enclosed by the stator core; characterized in that: The rotor core includes at least two fully connected bridge lamination groups and at least one semi-connected bridge lamination group, wherein the laminations in the fully connected bridge lamination group include a first central connecting bridge and a plurality of fully connected bridge punchings connected to the first central connecting bridge and distributed along the circumferential direction, and the laminations in the semi-connected bridge lamination group include a second central connecting bridge and at least one separate punching disconnected from the second central connecting bridge and distributed along the circumferential direction, adjacent sectors within the same lamination layer of the fully connected bridge lamination group are asymmetric, and the permanent magnets are placed in the slots between adjacent sectors; Adjacent sectors in the same laminated layer of the semi-connected bridge-type lamination stack are asymmetrical, the permanent magnets are placed in the slots between the adjacent sectors, and the second central connecting bridge extends radially outward along the corresponding slot to form a partition-type support bridge; The partitioned support bridge is separated from the permanent magnet; the first central connecting bridge has a support bridge, and the support bridge is in contact with the permanent magnet.

2. The permanent magnet motor according to claim 1, characterized in that The support bridge and the partition type support bridge partially overlap in the axial direction; the support bridge and the partition type support bridge have the same width on the shaft sleeve side.

3. The permanent magnet motor according to claim 1, characterized in that The fully connected bridge punching sheet has a first narrow magnetic bridge, and the width of the first narrow magnetic bridge is smaller than the width of the supporting bridge.

4. The permanent magnet motor according to claim 1, wherein: The distance between the partitioned support bridge and the permanent magnet is smaller than the length of the magnetic bridge of the fully connected bridge punching sheet.

5. The permanent magnet motor according to claim 1, characterized in that: The distance between the outermost side of the partition support bridge and the permanent magnet is greater than 0.5 mm.

6. The permanent magnet motor according to claim 1, characterized in that: The fully connected bridge lamination group includes multiple fully connected bridge laminations, and the semi-connected bridge lamination group includes multiple semi-connected bridge laminations. The fully connected bridge lamination group and the semi-connected bridge lamination group are stacked axially so that each semi-connected bridge lamination group is located between two fully connected bridge lamination groups.

7. The permanent magnet motor according to claim 6, characterized in that: The fully connected bridge-type laminations include a plurality of fully connected bridge punchings, and a support bridge is provided between adjacent fully connected bridge punchings; among two adjacent fully connected bridge punchings, one protrudes radially outward to form a wide magnetic bridge, and the other protrudes radially outward to form a first narrow magnetic bridge, and the width of the wide magnetic bridge is greater than the width of the first narrow magnetic bridge.

8. The permanent magnet motor according to claim 6, characterized in that: The semi-connected bridge type laminations include multiple semi-connected bridge punches and multiple separation punches. A separation punch is provided between two adjacent semi-connected bridge punches, and the separation punch does not contact the semi-connected bridge punch; there is a partition type support bridge between adjacent semi-connected bridge punches and the separation punches; the semi-connected bridge punches have a second narrow magnetic bridge, and a partition type wide magnetic bridge is provided on the second center connecting bridge, and the width of the partition type wide magnetic bridge is greater than the width of the second narrow magnetic bridge.

9. The permanent magnet motor according to claim 6, characterized in that: In at least one laminated layer of the semi-bridge type lamination stack, the second central connecting bridge extends radially outward to form a second narrow magnetic bridge.

10. The permanent magnet motor according to claim 1, characterized in that: The ratio of the number of fully connected bridge laminations in a fully connected bridge lamination group to the number of half-connected bridge laminations in a half-connected bridge lamination group is less than 0.

5.

11. The permanent magnet motor according to claim 1, characterized in that: The contact points between the stator core and the housing form a contact area, and the gaps between the stator core and the housing where they are not in contact form a filling area by injecting filling material.

12. The permanent magnet motor according to claim 1, wherein: The stator core includes a plurality of T-shaped tooth yokes, and each of the T-shaped tooth yokes is surrounded along the inner wall of the casing.

13. The permanent magnet motor according to claim 12, characterized in that: The number of the T-shaped tooth yokes is 12, so that the outer boundary of the stator core is a regular dodecagon; The outer surface of each T-shaped tooth yoke is parallel to the bottom of the stator slot, the boundary surface between the tooth portion and the yoke portion of the T-shaped tooth yoke is perpendicular, and the number of the T-shaped tooth yokes is equal to the number of motor slots.

14. The permanent magnet motor according to claim 13, characterized in that: Each of the T-shaped tooth yokes is provided with two inner and outer rivet points of different sizes, the diameter of the outer rivet point is larger than the diameter of the inner rivet point; the outer rivet point is located at the center of the yoke, and the inner rivet point is located in the middle of the tooth crown of the tooth part.

15. The permanent magnet motor according to claim 13, characterized in that: The tooth crown of the tooth portion is in an oblique shoulder shape and forms an oblique shoulder tooth crown groove, and the included angle between the inner oblique surface of the oblique shoulder tooth crown groove and the radial boundary of the tooth portion is an obtuse angle.

16. The permanent magnet motor according to claim 1, characterized in that: The laminations in the semi-connected bridge lamination group include a plurality of semi-connected bridge laminations and a plurality of said separation laminations, and the outer arc surface of each of the semi-connected bridge laminations and each of the said separation laminations includes a plurality of splines; The spline at least includes a circular arc segment main spline and straight line segment splines arranged on both sides of the circular arc segment main spline.

17. The permanent magnet motor according to claim 16, characterized in that: The number of segments x of the spline satisfies: If LCM(2P, S) / 2P is an odd number, then x=[LCM(2P, S) / 2P]; If LCM(2P, S) / 2P is an even number, then x=[LCM(2P, S) / 2P]-1; Among them, x, LCM, P, and S are the number of spline segments, the least common multiple, the number of pole pairs, and the number of slots, respectively.

18. The permanent magnet motor according to claim 17, characterized in that The central angle of the main arc segment spline is α, and the central angles of the remaining splines are βi, then:

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