A built-in permanent magnet motor

Abstract

The present invention relates to the field of permanent magnet motors, and discloses a built-in permanent magnet motor, comprising a housing, a stator core, a rotor core and a permanent magnet; 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 comprise a plurality of full-bridge punchings connected to a first central connecting bridge and distributed circumferentially, the laminations in the half-bridge lamination group comprise at least one separated punching that is disconnected from a second central connecting bridge and distributed circumferentially, and the full-bridge lamination group and the half-bridge lamination group are stacked axially, and each half-bridge lamination group is located between two full-bridge lamination groups, so that adjacent sectors in the same lamination layer of the full-bridge lamination group are asymmetric, and the permanent magnet is placed in the slot between the adjacent sectors. The present invention can simplify the production process of the motor and improve the structural strength of the motor.

Description

Technical Field

[0001] The present invention relates to the field of permanent magnet motors, and in particular to a built-in permanent magnet motor. Background Art

[0002] Traditional brushless DC motors use surface-mounted magnetic tiles or built-in radial magnetized magnetic steel structures, which have low power density. Due to cost factors, the magnetic flux per pole of the motor is increased through a tangential magnetization parallel magnetic circuit structure. The existing tangential magnetization structure still has the problem of large magnetic leakage, which limits the improvement of motor performance.

[0003] The existing rotor core has at least one tooth sector disconnected from the rotor ring, and at least one tooth sector connected to the sleeve. This suppresses magnetic leakage near the axis. The rotor core sleeve is provided with a positioning protrusion on the outside to position and support the permanent magnet. Through analysis, since the rotor disconnected tooth sector of this scheme has no fixed support parts in the axial direction, the axial structural strength is poor, which is not conducive to large-scale production. At the same time, the positioning protrusion used to support and position the permanent magnet will produce self-linkage leakage, reduce the power density of the motor, and is not conducive to improving performance.

[0004] 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 higher core losses and reducing motor efficiency. At the same time, the electromagnetic force wave is enhanced, resulting in increased vibration noise. The prior art 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 tooth portion extends inward from the stator annular yoke, and an embedded wire groove is formed between two adjacent stator teeth. The stator magnetic circuit is balanced, the magnetic flux density 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 density, and fails to consider the influence of the stator shape and structure on the motor magnetic field, loss, etc., and is not suitable for high power density motor structures. It also does not consider the combination method between the stator core and the casing to reduce the motor vibration noise, and does not provide a structure that can comprehensively consider the power density and suppress vibration and reduce noise.

[0005] Therefore, there is an urgent need for a permanent magnet brushless DC motor with simple process, reliable structure, high power density, and low vibration and noise that can be suitable for large-scale production. Summary of the invention

[0006] In order to overcome the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an internal permanent magnet motor, which can simplify the production process and improve the structural strength and power density.

[0007] In order to solve the above technical problems of the present invention, the present invention provides a built-in permanent magnet motor, comprising a housing (1), a stator core (2), a rotor core (3) and a permanent magnet (4); the stator core (2) is arranged along the circumferential direction of the inner wall of the housing (1), and the rotor core (3) is installed in a space surrounded by the stator core (2); the rotor core (3) comprises 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) comprise a plurality of full-bridge punchings (311) which are all connected to a first central connecting bridge (H1) and distributed along the circumferential direction, and the laminations in the half-bridge lamination group (32) comprise a plurality of full-bridge punchings (311) which are all connected to a first central connecting bridge (H1) and distributed along the circumferential direction. The laminations include at least one separated punching sheet (322) disconnected from the second central connecting bridge (H2) and distributed in the circumferential direction, and the full-bridge lamination group (31) and the half-bridge lamination group (32) are stacked in the axial direction 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 the permanent magnets (4) are placed in the slots between adjacent sectors; the contact points of the stator core (2) and the housing (1) form a contact area (22), and the gaps where the stator core (2) and the housing (1) are not in contact form a filling area (23) by injecting filling material.

[0008] Preferably, the fully connected bridge-type lamination group (31) comprises a plurality of fully connected bridge-type laminations, and adjacent fully connected bridge-type laminations are overlapped and stacked; and the semi-connected bridge-type lamination group (32) comprises a plurality of semi-connected bridge-type laminations, and adjacent semi-connected bridge-type laminations are overlapped and stacked.

[0009] Preferably, the stator core (2) comprises a plurality of T-shaped tooth yokes (21), and each of the T-shaped tooth yokes (21) is enclosed along the inner wall of the casing (1).

[0010] Preferably, the number of the T-shaped tooth yokes (21) is 12, so that the outer boundary of the stator core (2) is a regular dodecagon; the outer surface of each T-shaped tooth yoke (21) is parallel to the stator slot bottom (2111), the boundary surface between the tooth portion (212) of the T-shaped tooth yoke and the yoke portion (211) is perpendicular, and the number of the T-shaped tooth yokes (21) is equal to the number of motor slots.

[0011] Preferably, each of the T-shaped tooth yokes (21) is provided with two inner and outer rivet points of different sizes, the diameter of the outer rivet point (213) being greater than the diameter of the inner rivet point (214); the outer rivet point (213) is provided at the center of the yoke (211), and the inner rivet point (214) is provided at the middle of the tooth crown of the tooth portion (212); the tooth crown of the tooth portion (212) 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 (2121) and the radial boundary of the tooth portion is an obtuse angle.

[0012] Preferably, the fully-connected bridge type laminations include a plurality of fully-connected bridge punching sheets (311), and a supporting bridge (312) is provided between adjacent fully-connected bridge punching sheets (311); of two adjacent fully-connected bridge punching sheets (311), one of them protrudes radially outward to form a wide magnetic bridge (313), and the other protrudes radially outward to form a fully-connected narrow magnetic bridge (314), and the width of the wide magnetic bridge (313) is greater than the width of the fully-connected narrow magnetic bridge (314).

[0013] Preferably, the semi-connected bridge type laminations include a plurality of semi-connected bridge punches (321) and a plurality of separation punches (322), wherein 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 partition-type support bridge (323) is provided between adjacent semi-connected bridge punches (321); the semi-connected bridge punches (321) have a semi-connected bridge 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 semi-connected bridge narrow magnetic bridge (325).

[0014] Preferably, in at least one lamination layer of the semi-bridge type lamination stack (32), the second central connecting bridge (H2) extends radially outward to form the semi-bridge narrow magnetic bridge (325).

[0015] Preferably, the polarities of two adjacent permanent magnets (4) are different.

[0016] Preferably, adjacent sectors in the same lamination layer of the semi-bridge type lamination group (32) are asymmetric, the permanent magnet (4) is placed in the slot between adjacent sectors, the polarities of the permanent magnet (4) in two adjacent slots are different, and the corresponding second center connecting bridge (H2) in the slot extends radially outward to form a radial slot bottom protrusion; the support bridge (312) contacts the permanent magnet (4) and overlaps with the radial slot bottom protrusion axially; the support bridge (312) and the radial slot bottom protrusion are equal in width on the sleeve side; the radial slot bottom protrusion is separated from the permanent magnet (4), and the distance between the outermost side of the radial slot bottom protrusion and the permanent magnet (4) is greater than 0.5 mm.

[0017] Preferably, the outer arc surface of each of the fully connected bridge punching sheets (311) includes multiple sections of splines for reducing torque fluctuations;

[0018] 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.

[0019] Preferably, the splines include arc segment main splines, arc segment splines arranged on both sides of the arc segment main splines, and straight line segment splines arranged outside the two arc segment splines.

[0020] Preferably, the outer arc surface of each of the semi-bridge punching pieces (321) and each of the separation punching pieces (322) comprises a plurality of splines for reducing torque fluctuations;

[0021] 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.

[0022] Preferably, the splines include arc segment main splines, arc segment splines arranged on both sides of the arc segment main splines, and straight line segment splines arranged outside the two arc segment splines.

[0023] Preferably, 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.

[0024] Preferably, the number of segments x of the spline satisfies:

[0025] If LCM(2P, S) / 2P is an odd number, then x=[LCM(2P, S) / 2P];

[0026] If LCM(2P, S) / 2P is an even number, then x=[LCM(2P, S) / 2P]-1;

[0027] 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.

[0028] Preferably, assuming that the centrality of the main spline of the arc segment is α, and the central angles of the remaining splines are βi, then:

[0029]

[0030] The present invention can simplify the production process of the motor and improve the structural strength of the motor. By designing the partitioned support bridge and the partitioned wide magnetic bridge, the motor rotor structural strength is greatly improved. At the same time, the semi-connected bridge lamination ensures that at least half of the sectors of a lamination of the rotor core can be connected to the shaft sleeve, which is easy to position during large-scale production.

[0031] The present invention can significantly reduce the self-linkage magnetic leakage at the bottom of the rotor slot, thereby increasing the air gap magnetic flux. The T-shaped tooth yoke stator structure can reduce the motor saturation and maximize the magnetic flux per pole. By comparing the back-EMF coefficient of the motor structure of the present invention and the motor structure of the traditional full-bridge connection, it can be seen that the back-EMF coefficient of the motor using this structure is significantly improved. When the motor is running under heavy load, the linearity of the torque-current curve of the motor is good, and no saturation phenomenon occurs, thereby improving the motor performance.

[0032] The five-segment spline structure of the rotor reduces the harmonic distortion rate of the motor's back-EMF and improves the sinusoidal degree of the air gap magnetic field, thereby reducing the motor's tangential torque pulsation and radial vibration. At the same time, the T-type tooth yoke structure is adopted, and there is a filling area between the stator and the housing, thereby weakening the transmission of vibration between the stator itself and the housing, and achieving vibration reduction and noise reduction of the motor.

[0033] Reducing the self-linkage leakage at the bottom of the rotor slot and thus increasing the power density can ensure the high sinusoidality of the air gap magnetic field and significantly increase the back EMF coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0035] Figure 2 is a schematic structural diagram of a rotor core in one embodiment of the present invention;

[0036] Figure 3 1 is a schematic diagram of the structure of a T-shaped tooth yoke in one embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of the structure of a stator assembly in one embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of the structure of a semi-connected bridge-type lamination in one embodiment of the present invention;

[0039] Figure 6 is a schematic diagram of the structure of a fully connected bridge-type lamination in one embodiment of the present invention;

[0040] Figure 7 (a) is the self-linkage leakage magnetic distribution of the slot bottom of the full-bridge connection rotor in the prior art, and (b) is a partial enlarged view of the circled part in (a);

[0041] Figure 8 (a) is the self-linkage leakage magnetic distribution of the slot bottom of the bridge-type rotor without partition support in the prior art, and (b) is a partial enlarged view of the circled part in (a);

[0042] Fig. 9 (a) is the self-linkage leakage magnetic field distribution of the partition support bridge rotor slot bottom of the present invention, and (b) is a partial enlarged view of the circled portion in (a);

[0043] Fig.10 This is a comparison curve of the self-linkage leakage coefficient of the slot bottom near the axis of three motors with different structures;

[0044] Fig.11 Schematic diagram of the space inside the stator slot of a regular polygonal T-shaped tooth yoke in one embodiment of the present invention;

[0045] Fig.12 This is a schematic diagram of the space inside the stator slot of the traditional structure;

[0046] Fig.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;

[0047] Fig.14 is the no-load back EMF harmonic content of an embodiment of the present invention;

[0048] Fig.15 is a schematic diagram of the exploded structure of a rotor core in one embodiment of the present invention;

[0049] Fig.16 It is a schematic structural diagram of a semi-connected bridge type lamination stack in one embodiment of the present invention.

[0050] Description of Reference Numerals

[0051] Housing 1;

[0052] stator core 2; contact region 22; filling region 23;

[0053] 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;

[0054] Rotor core 3;

[0055] Fully connected bridge lamination set 31; fully connected bridge punching sheet 311; outer arc surface 3111; plastic coated through hole 3112; rivet point 3113; first center connecting bridge H1; support bridge 312; wide magnetic bridge 313; fully connected bridge narrow magnetic bridge 314;

[0056] Semi-connected bridge lamination group 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; semi-connected bridge narrow magnetic bridge 325;

[0057] Permanent magnet 4; shaft 5; winding 6; insulating frame 7. DETAILED DESCRIPTION

[0058] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0059] It should be noted in advance that, in the description of the present application, “axial direction” generally refers to the axial direction of the motor, that is, the extension direction along the rotation axis of the motor.

[0060] like Figure 1 , Figure 5 and Figure 6 As 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 a plurality of full-bridge punchings 311 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 separation punching 322 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 in the same lamination layer of the semi-bridge type lamination group 32 are asymmetric, 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-bridge punching sheets 321 in the slots extend radially outward to form radial slot bottom protrusions, which are separated from the permanent magnets 4, and the distance between the outermost side of the radial slot bottom protrusion and the permanent magnet 4 is greater than 0.5 mm.

[0061] like Fig.15 and 16 As shown, the full-bridge lamination group 31 includes a plurality of full-bridge laminations, and adjacent full-bridge laminations are overlapped and stacked; the half-bridge lamination group 32 includes a plurality of half-bridge laminations, and adjacent half-bridge laminations are overlapped and stacked.

[0062] like Figure 3 and 4As shown, the stator core 2 is enclosed by 12 T-shaped tooth yokes 21. The stator core 2 and the housing 1 are in contact through the connection points between adjacent T-shaped tooth yokes 21. The contact area forms a contact domain 22. The outer surface or top surface of the yoke 211 of each T-shaped tooth yoke 21 is a plane. The gap between it and the inner wall of the circular housing 1 forms a filling domain 23. The filling domain 23 can be filled with a variety of materials. In this example, the housing 1 is a bulk molding compound, and the bulk molding compound is also injected into the filling domain 23, that is, the housing 1 and the filling material are the same material. The mixture of the two plays a role in enhancing the stiffness of the motor, improving damping, and absorbing vibration. The winding 6 adopts flying fork winding. The designed stator slot type can effectively avoid flying fork winding interference and improve mass production efficiency.

[0063] like Figure 3 As shown, the outer surface of the yoke 211 of the T-shaped tooth yoke 21 is parallel to the stator slot bottom 2111, and 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 212. The tooth crown of the tooth portion 212 is in the shape of 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 straight line segment slope of the oblique shoulder tooth crown groove 2121 is 30°, the width of the tooth portion 212 at the narrowest point is 5.2 mm, and the height of the yoke portion 211 is 3.5 mm. Combined with the production process calculation, in this embodiment, Fig.11 As shown, the theoretically circumferential slot area of ​​the stator core 2 is compared with Fig.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.

[0064] like Figure 2 , 15 As shown in Figure 16, in this embodiment, the rotor core 3 includes two full-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 full-connected bridge-type lamination groups 31, that is, the two full-connected bridge-type lamination groups 31 are respectively located at the two 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.

[0065] The semi-bridge type lamination stack 32 is composed of Figure 5The multiple semi-connected bridge-type laminations shown are stacked and formed, and the semi-connected bridge-type 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 semi-connected bridge narrow magnetic bridge 325, and a partition-type wide magnetic bridge 324 is provided on the first center connecting bridge H1, and the width of the partition-type wide magnetic bridge 324 is greater than the width of the semi-connected bridge narrow magnetic bridge 325.

[0066] The full bridge type lamination group 31 is composed of Figure 6 The fully connected bridge type laminations shown are stacked, and the fully connected bridge type laminations include a plurality of fully connected bridge punching sheets 311 with support bridges 312 between adjacent ones; one of the two adjacent fully connected bridge punching sheets 311 protrudes radially outward to form a wide magnetic bridge 313, and the other protrudes radially outward to form a fully connected narrow magnetic bridge 314, and the width of the wide magnetic bridge 313 is greater than the width of the fully connected narrow magnetic bridge 314, and the fully connected bridge type laminations are axially opened with a plastic coating through hole 3112, and the semi-connected bridge type laminations are axially opened with a plastic coating through hole 3212, and the rotor core 3 is wrapped and reinforced by using plastic material to penetrate through the plastic coating through holes 3112 and 3212. The rivet points 3113, 3213 and 3223 are used for positioning and connection. The edge of the through hole of the punching sheet is 2.6 mm away from the boundary of the adjacent permanent magnet slot. 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 in which the rotor is formed entirely of half-connected bridge laminations, the back electromotive force coefficient of the motor in this embodiment is increased by 34.4%.

[0067] like Figure 6 As shown, the full-bridge lamination is a full-bridge structure, wherein the 10 full-bridge punching sheets 311 included therein are all connected as a whole through the first central connecting bridge H1, the first central connecting bridge H1 includes a plurality of support bridges 312, a plurality of wide magnetic bridges 313 and a plurality of full-bridge narrow magnetic bridges 314, and the first central connecting bridge H1 is a continuous whole. The thickness of the permanent magnet 4 selected in this embodiment is 5 mm, the width of the full-bridge narrow magnetic bridge 314 is 0.8 mm, the width of the wide magnetic bridge 313 is 1.5 mm, the length of the magnetic bridge is 2.8 mm, and the width of the support bridge 312 is 1.2 mm. The support bridge 312 contacts the permanent magnet 4, the support bridge 312 and the radial groove bottom protrusion are axially overlapped, and the width of the support bridge 312 and the radial groove bottom protrusion on the sleeve side is equal.

[0068] like Figure 5As shown, the semi-connected bridge lamination is a semi-connected bridge structure, in which the five separated punching sheets 322 included therein are all disconnected from the second center connecting bridge H2, that is, the five separated punching sheets 322 are not connected to the second center connecting bridge H2, and are in a separated state from the second center connecting bridge H2. The second center connecting bridge H2 includes a plurality of partitioned support bridges 323, a plurality of partitioned wide magnetic bridges 324, and a plurality of semi-connected narrow magnetic bridges 325. The second center connecting bridge H2 is a continuous whole. Of course, the number of separated punching sheets 322 is not limited to 5, and can be 1-4, or other numbers. The width of the semi-connected narrow magnetic bridge 325 is 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, and comparing the magnetic field distribution of the full-bridge connected rotor structure, the non-partitioned support bridge structure and the present embodiment, and calculating the self-linkage leakage magnetic flux coefficient, see Fig.10 It can be obtained that the slot bottom self-linkage leakage coefficients of the three structural motors, namely A full-connected bridge type, B non-partitioned support bridge type and C hybrid bridge type of the present invention, are 0.207, 0.065 and 0.018 respectively, which proves that the present embodiment can greatly reduce the slot bottom self-linkage leakage coefficient, thereby greatly improving the power density of the motor.

[0069] like Figure 5 , Figure 6 and Fig.13 As shown, the outer arc surface of the full-bridge lamination and the semi-bridge lamination adopts a five-segment spline structure to reduce torque fluctuations 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 that is 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°.

[0070] By comparing and analyzing the full-circle structure rotor, the traditional three-segment arc structure rotor and the five-segment spline rotor of this embodiment, the optimal no-load back EMF distortion rate is only 1.18%, and the corresponding harmonic components are as follows: Fig.14 In this embodiment, the rotor surface is molded by using bulk molding compound, and the maximum structural failure speed of the motor is 19000rpm, which is more than 6 times higher than the actual operating speed of the motor. This proves that the rotor surface structure design of this embodiment can ensure the high sinusoidality of the air gap magnetic field and sufficient structural strength.

[0071] 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, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0072] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0073] In addition, 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 built-in permanent magnet motor, comprising a housing (1), a stator core (2), a rotor core (3) and a permanent magnet (4); the stator core (2) is arranged along the circumference of the inner wall of the housing (1), and the rotor core (3) is installed in a space enclosed by the stator core (2); characterized in that: The rotor core (3) comprises 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) comprise a plurality of full-bridge punchings (311) which are all connected to the first central connecting bridge (H1) and distributed along the circumferential direction, and the laminations in the half-bridge lamination group (32) comprise at least one separated punching (322) which 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 in the axial direction such 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 the permanent magnets (4) are placed in the slots between the adjacent sectors; The contact points between the stator core (2) and the housing (1) form a contact region (22), and the gap between the stator core (2) and the housing (1) where no contact is made forms a filling region (23) by injecting a filling material.

2. The interior permanent magnet motor according to claim 1, characterized in that: The fully connected bridge-type lamination group (31) comprises a plurality of fully connected bridge-type laminations, and adjacent fully connected bridge-type laminations are overlapped and stacked; The semi-connected bridge-type lamination group (32) comprises a plurality of semi-connected bridge-type laminations, and adjacent semi-connected bridge-type laminations are overlapped and stacked.

3. The interior permanent magnet motor according to claim 1, characterized in that: The stator core (2) comprises a plurality of T-shaped tooth yokes (21), and each of the T-shaped tooth yokes (21) is enclosed along the inner wall of the casing (1).

4. The interior permanent magnet motor according to claim 3, characterized in that: The number of the T-shaped tooth yokes (21) is 12, so that the outer boundary of the stator core (2) is a regular dodecagon; The outer surface of each T-shaped tooth yoke (21) is parallel to the stator slot bottom (2111), the boundary surface between the tooth portion (212) of the T-shaped tooth yoke and the yoke portion (211) is perpendicular, and the number of the T-shaped tooth yokes (21) is equal to the number of motor slots.

5. The interior permanent magnet motor according to claim 4, characterized in that: Each of the T-shaped toothed yokes (21) is provided with two inner and outer rivet points of different sizes, and the diameter of the outer rivet point (213) is larger than the diameter of the inner rivet point (214); The outer rivet point (213) is arranged at the center of the yoke (211), and the inner rivet point (214) is arranged at the middle of the tooth crown of the tooth portion (212); The tooth crown of the tooth portion (212) is in the shape of an oblique shoulder type, and the included angle between the inner inclined surface of the oblique shoulder type tooth crown groove (2121) and the radial boundary of the tooth portion is an obtuse angle.

6. The interior permanent magnet motor according to claim 2, characterized in that: The fully connected bridge type lamination comprises a plurality of fully connected bridge punching sheets (311), wherein a support bridge (312) is provided between adjacent fully connected bridge punching sheets (311); of two adjacent fully connected bridge punching sheets (311), one of them protrudes radially outward to form a wide magnetic bridge (313), and the other protrudes radially outward to form a fully connected narrow magnetic bridge (314), wherein the width of the wide magnetic bridge (313) is greater than the width of the fully connected narrow magnetic bridge (314).

7. The interior permanent magnet motor according to claim 6, characterized in that: The semi-connected bridge type laminations include a plurality of semi-connected bridge punches (321) and a plurality of 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 partition type support bridge (323) is provided between adjacent semi-connected bridge punches (321); the semi-connected bridge punches (321) have a semi-connected bridge narrow magnetic bridge (325); a partition type wide magnetic bridge (324) is provided on the second center connection bridge (H2), and the width of the partition type wide magnetic bridge (324) is greater than the width of the semi-connected bridge narrow magnetic bridge (325).

8. The interior permanent magnet motor according to claim 7, characterized in that: In at least one lamination layer of the semi-bridge type lamination stack (32), the second central connecting bridge (H2) extends radially outward to form the semi-bridge narrow magnetic bridge (325).

9. The interior permanent magnet motor according to claim 1, characterized in that: The polarities of two adjacent permanent magnets (4) are different.

10. The interior permanent magnet motor according to claim 8, characterized in that: Adjacent sectors in the same lamination layer of the semi-bridge type lamination group (32) are asymmetric, the permanent magnets (4) are placed in the slots between the adjacent sectors, the polarities of the permanent magnets (4) in two adjacent slots are different, and the corresponding second central connecting bridges (H2) in the slots extend radially outward to form radial slot bottom protrusions; The support bridge (312) contacts the permanent magnet (4) and overlaps with the radial groove bottom protrusion along the axial direction; the width of the support bridge (312) and the radial groove bottom protrusion on the shaft sleeve side are equal; The radial groove bottom protrusion is separated from the permanent magnet (4), and the distance between the outermost side of the radial groove bottom protrusion and the permanent magnet (4) is greater than 0.5 mm.

11. The interior permanent magnet motor according to claim 6, characterized in that: The outer arc surface of each of the full-bridge punching sheets (311) comprises a plurality of splines for reducing torque fluctuations; 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.

12. The interior permanent magnet motor according to claim 11, characterized in that: 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.

13. The interior permanent magnet motor according to claim 7, characterized in that: The outer arc surface of each of the semi-bridge punching pieces (321) and each of the separation punching pieces (322) comprises a plurality of splines for reducing torque fluctuations; 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.

14. The interior permanent magnet motor according to claim 13, characterized in that: 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.

15. The interior 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 (31) to the number of half-connected bridge laminations in a half-connected bridge lamination group (32) is less than 0.

5.

16. The interior permanent magnet motor according to any one of claims 11 to 14, 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.

17. The interior permanent magnet motor according to claim 16, characterized in that The centrality of the main spline of the arc segment is α, and the central angles of the remaining splines are βi, respectively, then:

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