Rotor structure and motor

Abstract

The present disclosure provides a rotor structure and a motor, the rotor structure including a first rotor core, a second rotor core having a plurality of mounting grooves spaced apart along the circumferential direction, a first permanent magnet that is axially magnetized and includes a first polarity and a second polarity, and a plurality of second permanent magnets that include a third polarity and a fourth polarity and are mounted in a one-to-one correspondence with the mounting grooves, wherein the first permanent magnets are mounted at both ends of the second rotor core along the axial direction, and the first rotor core is mounted on the side of the first permanent magnet that is away from the second rotor core along the axial direction, and the polarity arrangement order of the first permanent magnet and the plurality of second permanent magnets along the counterclockwise direction in a projection plane projected onto one end face of the second rotor core along the axial direction is the first polarity, the third polarity, the second polarity, and the fourth polarity, where the first polarity and the third polarity are the same, and the second polarity and the fourth polarity are the same.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This disclosure is based on and claims priority from a Chinese patent application filed on November 29, 2022, bearing application number 202211510763.1, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to the technical field of motors, and more particularly to rotor structures and motors. [Background technology]

[0003] As motor energy efficiency standards improve, the requirements for motor energy efficiency levels become higher, and permanent magnet motors need to have even higher motor efficiency and torque density.

[0004] Currently, one technical method for improving motor efficiency and torque density is to incorporate permanent magnets to obtain greater air gap magnetic flux density and magnetic flux amount, but this limits the improvement in energy efficiency because the rotor magnetic path structure is fixed.Another method is to increase the motor's salient pole ratio by changing the rotor structure, thereby increasing the motor's magnetic resistance torque and compensating for the lack of permanent magnet torque.While this method can achieve efficiency comparable to that of a permanent magnet motor, it usually requires a larger rotor volume, resulting in a motor with lower torque density than a permanent magnet motor.

[0005] In a motor employing a built-in permanent magnet structure, magnetic flux leakage is likely to occur at the end where the permanent magnet is built in, resulting in a decrease in the no-load magnetic flux linkage of the motor. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present disclosure is mainly to provide a rotor structure and a motor, which can reduce the magnetic flux leakage at the end of the second permanent magnet and improve the no-load magnetic flux linkage of the motor. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the present disclosure is to a first rotor core; a second rotor core having a plurality of mounting grooves spaced apart along the circumferential direction; a first permanent magnet that is axially magnetized and includes a first polarity and a second polarity; a plurality of second permanent magnets including a third polarity and a fourth polarity and attached to the plurality of attachment grooves in a one-to-one correspondence; A first permanent magnet is installed at each end of the second rotor core along the axial direction, and the first rotor core is installed on the side of the first permanent magnet that is away from the second rotor core along the axial direction, The rotor structure provides a rotor in which, within a projection plane projected onto one end face of the second rotor core along the axial direction, the polarity arrangement order of the first permanent magnet and the plurality of second permanent magnets along the counterclockwise direction is a first polarity, a third polarity, a second polarity, and a fourth polarity, of which the first polarity and the third polarity are the same, and the second polarity and the fourth polarity are the same.

[0008] In some embodiments, the first permanent magnet is divided into a plurality of magnetized areas along the circumferential direction, and two adjacent magnetized areas are magnetized in opposite directions, and both sides of each magnetized area in the circumferential direction partially overlap two adjacent second permanent magnets in a projection plane in the axial direction; Two adjacent second permanent magnets are magnetized in opposite directions, and a magnetic field region is defined by each magnetized area and the two adjacent second permanent magnets, with the polarity of the side of the magnetized area facing the magnetic field region being the same as the polarity of the sides of the two adjacent second permanent magnets facing the magnetic field region.

[0009] In some embodiments, the magnetized area of ​​the first permanent magnet covers the same polarity section of the adjacent second permanent magnet on a first circumferential side and covers the same polarity section of the adjacent second permanent magnet on a second circumferential side.

[0010] In some embodiments, within a projection plane projected onto one end face of the second rotor core along the axial direction, the deviation between the geometric center line of at least one pair of poles of the first permanent magnet and the center line of the rotor magnetic field of the corresponding second rotor core is 5° or less.

[0011] In some embodiments, the geometric centerlines of at least one pair of poles of the first permanent magnet overlap the centerline of the rotor magnetic field of the corresponding second rotor core.

[0012] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the angle formed by the connecting line between the two end points of one pole of the first permanent magnet closest to the outer circumference of the rotor and the center of the second rotor core is α, and the angle formed by the connecting line between the two end points of the magnetic conductive portion of one pole of the second rotor core closest to the outer circumference of the rotor and the center of the second rotor core is β, then α / β≧1.

[0013] In some embodiments, 1≦α / β≦1.62.

[0014] In some embodiments, in a projection plane projected along the axial direction onto one end face of the second rotor core, if the angle formed by the connecting line between the two end points of one pole of the first permanent magnet closer to the rotor outer circumference and the center of the second rotor core is α, and the angle formed by the connecting line between the two end points of one pole of the second permanent magnet closer to the rotor outer circumference and the center of the second rotor core is γ, then α / γ>1.

[0015] In some embodiments, 2.0≦α / γ≦3.2.

[0016] In some embodiments, in a projection plane projected along the axial direction onto one end face of the second rotor core, if the angle formed by the connecting line between the two end points of one pole of the first permanent magnet closest to the outer circumference of the rotor and the center of the second rotor core is α and the pole arc angle of one pole of the second rotor core is 360 / 2p, then 360 / 2p / α≧1, where p is the number of pole pairs of the second rotor core.

[0017] In some embodiments, 1.3≧360 / 2p / α≧1.

[0018] In some embodiments, in a projection plane projected onto one end face of the second rotor core along the axial direction, if the area of ​​one pole of the first permanent magnet is s1 and the area of ​​one pole of the second rotor core is s2, then s1 / s2≧1.

[0019] In some embodiments, 1.05≦s1 / s2≦1.95.

[0020] In some embodiments, in a projection plane projected onto one end face of the second rotor core along the axial direction, the area of ​​one pole of the first permanent magnet is s1, the area of ​​one pole of the second permanent magnet is s3, and in a cross section passing through the central axis of the second rotor core, the area of ​​one pole of the first permanent magnet is s4, and the area of ​​one pole of the second permanent magnet is s5, then 0.8*s3≦s1≦2.4*s5 and / or 0.3*s3≦s4≦0.8*s5 hold.

[0021] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the area of ​​one pole of the first permanent magnet is s1 and the length of the connecting line between the central axis of the second rotor core and any point on the outer circumference is j, then 1≦s1 / max(j)≦20.

[0022] In some embodiments, 3≦s1 / max(j)≦16.

[0023] In some embodiments, within a projection plane projected onto one end face of the second rotor core along the axial direction, the area of ​​one pole of the first permanent magnet is s1, the area of ​​one pole of the second rotor core is s2, and the area of ​​one pole of the second permanent magnet is s3, where 0.2≦s2 / (s1+s3)≦1.

[0024] In some embodiments, 0.3≦s2 / (s1+s3)≦0.6.

[0025] In some embodiments, in a projection plane projected onto one end face of the second rotor core along the axial direction, if the area of ​​one pole of the first permanent magnet is s1 and the thickness of the first permanent magnet along the axial direction of the second rotor core is b, s1 and b are negatively correlated.

[0026] In some embodiments, the relationship between s1 and b satisfies the dimensionless equation s1=-A*b+C, where A ranges from 5 to 20 and C ranges from 120 to 400.

[0027] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the sum of the angles formed by the connecting lines between the two end points of each pole of the first permanent magnet closest to the outer circumference of the rotor and the center of the second rotor core is α*2q and the ratio of this angle to the circumferential angle of the second rotor core is a, then a = α*2q / 360, and if the thickness of the first permanent magnet along the axial direction of the second rotor core is b, then 2≦b / a≦6, where q is the number of pole pairs of the first permanent magnet.

[0028] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the sum of the angles formed by the connecting lines between the two end points of each pole of the first permanent magnet closest to the outer circumference of the rotor and the center of the second rotor core is α*2q and the ratio of this angle to the circumferential angle of the second rotor core is a, then a = α*2q / 360, and if the thickness of the first permanent magnet along the axial direction of the second rotor core is b, then 1.7≦a*b≦12.

[0029] In some embodiments, 2≦a*b≦10.

[0030] In some embodiments, if the thickness of the first permanent magnet along the axial direction of the second rotor core is b and the thickness of the second permanent magnet along the magnetization direction is m, then 0.2≦b / m≦2 holds.

[0031] In some embodiments, 0.4≦b / m≦1.4.

[0032] In some embodiments, if the thickness of the first permanent magnet along the axial direction of the second rotor core is b and the thickness of the first rotor core along the axial direction of the second rotor core is c, c is greater than or equal to the thickness of the single punched piece of the second rotor core, and 0.1≦c / b≦1.

[0033] In some embodiments, a magnetic shielding groove is provided on the side of the mounting groove closer to the central axis of the second rotor core, and the projection of the first permanent magnet is configured to partially cover the projection of the magnetic shielding groove within a projection plane projected onto one end face of the second rotor core along the axial direction.

[0034] In some embodiments, the proportion of the coverage area of ​​the projection of the first permanent magnet relative to the projection of the magnetic shielding groove to the projection area of ​​the magnetic shielding groove is 75% or less.

[0035] In some embodiments, the proportion of the coverage area of ​​the projection of the first permanent magnet relative to the projection of the magnetic shielding groove to the projected area of ​​the magnetic shielding groove is 25% or less.

[0036] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the maximum value of the length of the connecting line between the central axis of the second rotor core and the center of the edge of one pole of the first permanent magnet that is closer to the outer circumference of the rotor is defined as max(i), and the maximum value of the connecting lines between the central axis of the second rotor core and each point on the outer circumference of the second rotor core is defined as max(j), then max(i)≦max(j).

[0037] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the length of the connecting line between the central axis of the second rotor core and the center of the end edge of one pole of the second permanent magnet that is closer to the outer circumference of the rotor is ii, then max(j)≧max(i)≧0.8*ii.

[0038] In some embodiments, max(j)≧max(i)≧0.95*ii.

[0039] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, the length of the connecting line between the central axis of the second rotor core and the center of the radially inner edge of one pole of the first permanent magnet is d, and the length of the connecting line between the central axis of the second rotor core and the center of the end edge of one pole of the first permanent magnet that is closer to the outer circumference of the rotor is i, where 0.2≦d / max(i)≦0.8.

[0040] In some embodiments, 0.3≦d / max(i)≦0.6.

[0041] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the length of the connecting line between the central axis of the second rotor core and the center of the radially inner edge of one pole of the first permanent magnet is d and the length of the connecting line between the central axis of the second rotor core and the center of the radially inner edge of one pole of the second permanent magnet is f, then 0≦d / f≦2 holds.

[0042] In some embodiments, 0.8≦d / f≦1.6.

[0043] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the length of the connecting line between the central axis of the second rotor core and the center of the edge of one pole of the first permanent magnet closer to the rotor outer circumference is i, the length of the connecting line between the central axis of the second rotor core and each point on the rotor outer circumference of the second rotor core is j, and the length of the connecting line between the central axis of the second rotor core and each point on the rotor outer circumference of the first rotor core is h, then max(h)≦max(j) and / or min(h)≧0.8*max(i).

[0044] In some embodiments, 0.9≦min(h) / max(i)≦1.4.

[0045] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the length of the connecting line between the central axis of the second rotor core and the center of the radially inner edge of one pole of the first permanent magnet is d and the length of the connecting line between the central axis of the second rotor core and each point on the radially inner edge of the first rotor core is k, then max(k)≦d.

[0046] In some embodiments, 0.2≦max(k) / d≦1.

[0047] In some embodiments, within a projection plane projected along the axial direction onto one end face of the second rotor core, if the minimum value of the radial width e of the first permanent magnet is min(e) and the maximum value of the radial width g of the second permanent magnet is max(g), then 0.5≦min(e) / max(g)≦2 holds.

[0048] In some embodiments, 0.6≦min(e) / max(g)≦1.6.

[0049] In some embodiments, in a projection plane projected onto one end face of the second rotor core (2) along the axial direction of the second rotor core (2), if the maximum value of the radial width e of the first permanent magnet (3) is max(e) and the maximum value of the radial width o of the second rotor core (2) is max(o), then max(e)≦max(o).

[0050] In some embodiments, 0.3≦max(e) / min(o)≦1 and / or 0.4≦max(e) / max(o)≦0.95.

[0051] In some embodiments, within a projection plane projected onto one end face of the second rotor core along the axial direction, if the maximum value of the radial width e of the first permanent magnet is max(e) and the minimum value of the radial width l of the first rotor core is min(l), then 0.7≦min(l) / max(e)≦3 holds.

[0052] In some embodiments, 1≦min(l) / max(e)≦2.

[0053] In some embodiments, in a projection plane projected onto one end face of the second rotor core along the axial direction, if the area of ​​one pole of the first permanent magnet is s1 and the height of the second rotor core along the central axis direction is x, s1 and x are negatively correlated.

[0054] In some embodiments, s1=-B*x+D, where B ranges from 25 to 100 and D ranges from 400 to 1600.

[0055] In some embodiments, if the thickness of the first rotor core along the central axis direction of the second rotor core is c and the thickness of the second permanent magnet along the magnetization direction is m, then 0.1*m≦c≦m.

[0056] In some embodiments, 0.1*m≦c≦0.5*m.

[0057] Another aspect of the present disclosure provides a motor including a stator structure and the rotor structure described above, wherein the stator structure is fitted to the outside of the rotor structure.

[0058] In some embodiments, the stator structure includes a stator core, and an outer diameter of a first permanent magnet located at at least one end of the second rotor core is smaller than an inner diameter of the stator core.

[0059] In some embodiments, the outer diameter of the first permanent magnet located at at least one end of the second rotor core is smaller than the largest of the outer diameters of the first rotor core and the second rotor core.

[0060] In some embodiments, an air gap is formed between the stator structure and the rotor structure, and w is the difference between the maximum outer diameter of the second rotor core of the rotor structure and the maximum outer diameter of the first permanent magnet, where w is w≧0.

[0061] In some embodiments, where δ is the thickness of the air gap, 0.5*min(δ)≦w≦14*min(δ).

[0062] In some embodiments, the stator structure includes a stator core, where x is the height of the second rotor core along the axial direction of the motor, and y is the height of the stator core along the axial direction of the motor, and x / y≦2.

[0063] In some embodiments, 0.5≦x / y≦1.5.

[0064] In some embodiments, the stator structure includes a stator core, where z is the total height of the rotor structure along the axial direction of the motor, and y is the height of the stator core along the axial direction of the motor, and z / y≦4.

[0065] In some embodiments, 1.0≦z / y≦3.0.

[0066] In some embodiments, the stator structure includes a stator core, where x is the height of the second rotor core along the axial direction of the motor, y is the height of the stator core along the axial direction of the motor, and b is the height of the first permanent magnet along the axial direction of the motor, and 0.01x≦b≦0.7x and / or 0.015y≦b≦0.9y.

[0067] In some embodiments, the motor includes a rotating shaft and a cover plate attached to at least one end of the rotating shaft, wherein the minimum outer diameter of the cover plate is greater than the inner diameter of the stator core, and where E is the axial distance between the cover plate and the stator core, 1.2y≦E≦2.3y.

[0068] According to the technical aspects of the present disclosure, the rotor structure includes a first rotor core, a second rotor core having a plurality of mounting grooves spaced apart along the circumferential direction, a first permanent magnet that is magnetized in the axial direction and includes a first polarity and a second polarity, and a plurality of second permanent magnets that include a third polarity and a fourth polarity and are attached to the plurality of mounting grooves in a one-to-one correspondence, wherein the first permanent magnets are installed at both ends of the second rotor core along the axial direction, and the first rotor core is installed on the side of the first permanent magnet that is away from the second rotor core along the axial direction, and within a projection plane projected onto one end face of the second rotor core along the axial direction, the polarity arrangement order of the first permanent magnet and the plurality of second permanent magnets along the counterclockwise direction is the first polarity, the third polarity, the second polarity, and the fourth polarity, wherein the first polarity and the third polarity are the same, and the second polarity and the fourth polarity are the same.

[0069] According to this rotor structure, the polarity arrangement order of the first permanent magnet and the multiple second permanent magnets along the counterclockwise direction is first polarity, third polarity, second polarity, and fourth polarity, of which the first polarity and the third polarity are identical, and the second polarity and the fourth polarity are identical. The magnetic field lines of the first polarity and second polarity of the first permanent magnet enter the rotor core along the axial direction, while the magnetic field lines of the third polarity and fourth polarity of the second permanent magnet enter the rotor core along the tangential direction or radial direction. As a result of these two sets of magnetic field line directions interfering with each other on the rotor core, both sets of magnetic field lines can enter the air gap, and can only enter the air gap. This increases the air gap magnetic flux density, effectively reduces magnetic flux leakage at both ends of the second permanent magnet, and improves no-load flux linkage.

[0070] The accompanying drawings of the specification that form a part of this application are used to provide a further understanding of the present disclosure, and the exemplary embodiments of the present disclosure and the description thereof are used to interpret the present disclosure and are not intended to unduly limit the present disclosure. [Brief explanation of the drawings]

[0071] [Figure 1] 1 shows a perspective view of a rotor structure according to an embodiment of the present disclosure; [Figure 2] 1 shows an exploded view of a rotor structure according to an embodiment of the present disclosure. [Figure 3] 1 shows a cross-sectional configuration diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 4] 1 shows a structural layout diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 5] 1 shows a cross-sectional configuration diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 6] 1 shows a dimensional block diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 7] 1 shows a dimensional block diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 8] 1 shows a dimensional block diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 9] 1 shows a dimensional block diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 10] 1 shows a perspective configuration diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 11] FIG. 1 shows a diagram illustrating the relationship between the polar arrangement and no-load flux linkage of a rotor structure according to an embodiment of the present disclosure. [Figure 12] FIG. 10 shows a relationship diagram of the no-load flux linkage and the angular deviation between the geometric center line of the first permanent magnet and the center line of the magnetic field in the rotor structure of the embodiment of the present disclosure. [Figure 13] FIG. 10 shows a relationship diagram between α / β and permanent magnet utilization rate in a rotor structure according to an embodiment of the present disclosure. [Figure 14] FIG. 10 shows a relationship diagram of α / γ, permanent magnet utilization rate, and magnetic flux leakage coefficient in a rotor structure according to an embodiment of the present disclosure. [Figure 15] FIG. 10 shows a relationship diagram of 360 / 2p / α, space utilization rate, and saturation coefficient in a rotor structure according to an embodiment of the present disclosure. [Figure 16] FIG. 10 is a diagram showing the relationship between b / a and the permanent magnet utilization rate and the permanent magnet demagnetization rate in a rotor structure according to an embodiment of the present disclosure. [Figure 17] FIG. 10 shows a relationship diagram between s1 / s2 and permanent magnet utilization rate in a rotor structure according to an embodiment of the present disclosure. [Figure 18] FIG. 10 shows a relationship diagram between b / m and permanent magnet demagnetization factor in a rotor structure according to an embodiment of the present disclosure. [Figure 19] FIG. 10 is a diagram showing the relationship between c / m and no-load flux linkage utilization and iron loss in a rotor structure according to an embodiment of the present disclosure. [Figure 20] FIG. 10 is a comparison diagram of the magnetic flux leakage coefficient between a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 21] 10A and 10B are diagrams illustrating a comparison of air gap magnetic flux density waveforms between a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 22] 1 shows a comparison diagram of air gap magnetic flux density amplitude between a motor according to an embodiment of the present disclosure and a motor according to the prior art; [Figure 23] FIG. 10 shows a comparison diagram of no-load flux linkage between a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 24] FIG. 1 shows a comparison of output torque-current curves of a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 25]FIG. 10 is a comparison diagram of output torque at the same current between a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 26] 1 shows a comparison diagram of efficiency curves of a motor according to an embodiment of the present disclosure and a motor according to the prior art; [Figure 27] FIG. 10 shows a comparison of copper loss curves between a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 28] FIG. 10 shows a comparison diagram of iron loss between a motor according to an embodiment of the present disclosure and a motor according to the prior art. [Figure 29] FIG. 10 shows a relationship diagram between s1 / s3 and no-load flux linkage in a rotor structure according to an embodiment of the present disclosure. [Figure 30] FIG. 10 shows a relationship diagram between s1 / s5 and no-load flux linkage utilization rate in a rotor structure according to an embodiment of the present disclosure. [Figure 31] FIG. 10 shows a relationship diagram between s4 / s3 and permanent magnet demagnetization factor in a rotor structure according to an embodiment of the present disclosure. [Figure 32] FIG. 10 shows a relationship diagram between s4 / s5 and the motor saturation coefficient in the rotor structure of the embodiment of the present disclosure. [Figure 33] FIG. 10 shows a relationship diagram between s1 / max(j) and a magnetic flux collection coefficient in a rotor structure according to an embodiment of the present disclosure. [Figure 34] FIG. 10 shows a relationship diagram of s2 / (s1+s3), the utilization rate of the rotor core, and iron loss in a rotor structure according to an embodiment of the present disclosure. [Figure 35] 10 shows a curve diagram of the relationship between b and iron loss and copper loss at s1 in the rotor structure of the embodiment of the present disclosure. [Figure 36] FIG. 10 shows a curve diagram of the relationship between a*b, the air gap magnetic flux density, and the first permanent magnet utilization rate in a rotor structure according to an embodiment of the present disclosure. [Figure 37] FIG. 10 shows a curve diagram of the relationship between c / b, the saturation coefficient, and the utilization rate of the rotor core in the rotor structure of the embodiment of the present disclosure. [Figure 38] 1 shows a schematic diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 39] 1 shows a schematic diagram of a first permanent magnet in a rotor structure according to an embodiment of the present disclosure. [Figure 40]3A and 3B are schematic diagrams illustrating the configuration of a second rotor core in a rotor structure according to an embodiment of the present disclosure. [Figure 41] 1 is a schematic diagram illustrating the configuration of a motor according to an embodiment of the present disclosure. [Figure 42] FIG. 10 is a diagram showing the relationship between the coverage area proportion of the first permanent magnet to the magnetic shielding groove, the no-load magnetic flux linkage, and the permanent magnet utilization rate in a rotor structure according to an embodiment of the present disclosure. [Figure 43] 1 shows a dimensional block diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 44] FIG. 10 shows a relationship diagram between max(i) / ii and the top magnetic flux leakage coefficient of the second permanent magnet in the rotor structure of the embodiment of the present disclosure. [Figure 45] FIG. 10 shows a relationship diagram of d / f, the bottom magnetic flux leakage coefficient of the second permanent magnet, and the utilization rate of the first permanent magnet in a rotor structure according to an embodiment of the present disclosure. [Figure 46] 1 shows a dimensional block diagram of a rotor structure according to an embodiment of the present disclosure; [Figure 47] FIG. 10 shows a relationship diagram between min(h) / max(i) and no-load flux linkage in a rotor structure according to an embodiment of the present disclosure. [Figure 48] FIG. 10 shows a relationship diagram between max(k) / d and no-load flux linkage in a rotor structure according to an embodiment of the present disclosure. [Figure 49] FIG. 10 shows a relationship diagram between min(e) / max(g) and magnetic flux leakage coefficient in a rotor structure according to an embodiment of the present disclosure. [Figure 50] FIG. 10 shows a relationship diagram of max(e) / min(o) and max(e) / max(o) and the saturation coefficient of the second rotor core in the rotor structure of the embodiment of the present disclosure. [Figure 51] FIG. 10 shows a relationship diagram between min(l) / max(e) and the saturation coefficient of the first rotor core in the rotor structure of the embodiment of the present disclosure. [Figure 52] FIG. 10 shows a relationship diagram of x / y, the utilization rate of the second rotor core, and the utilization rate of the stator magnetic field in the rotor structure of the embodiment of the present disclosure. [Figure 53] 10 shows a relationship diagram of s1, iron loss, and copper loss at x in a rotor structure according to an embodiment of the present disclosure. [Figure 54]FIG. 10 shows a relationship diagram between z / y and the utilization rate of the stator core in the rotor structure of the embodiment of the present disclosure. [Figure 55] FIG. 10 shows a relationship diagram between b / x, b / y and the saturation coefficient of the second rotor core in the rotor structure of the embodiment of the present disclosure. [Figure 56] A schematic diagram of a cross-sectional configuration along the AA direction in FIG. 38 is shown. DETAILED DESCRIPTION OF THE INVENTION

[0072] It should be noted that, unless there is a contradiction, the embodiments and features of the embodiments of the present application can be combined. The present disclosure will be described in detail below in conjunction with the embodiments with reference to the accompanying drawings.

[0073] 1 to 56, according to an embodiment of the present disclosure, a rotor structure includes a first rotor core 1, a second rotor core 2 in which a plurality of mounting grooves are provided at intervals along the circumferential direction, a first permanent magnet 3 that is magnetized in the axial direction and includes a first polarity 5 and a second polarity 6, and a plurality of second permanent magnets 4 that include a third polarity 7 and a fourth polarity 8 and are attached to the plurality of mounting grooves in a one-to-one correspondence, and the first permanent magnets 3 are respectively provided at both ends of the second rotor core 2 along the axial direction, and the first The first rotor core 1 is installed on the side away from the second rotor core 2 along the axial direction of the permanent magnet 3, and in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the polarity arrangement order of the first permanent magnet 3 and the multiple second permanent magnets 4 along the counterclockwise direction is the first polarity 5, the third polarity 7, the second polarity 6, and the fourth polarity 8, of which the first polarity 5 and the third polarity 7 are the same, and the second polarity 6 and the fourth polarity 8 are the same.

[0074] The above-mentioned projection plane is perpendicular to the central axis of the second rotor core 2, and the first rotor core 1, the second rotor core 2, the first permanent magnet 3 and the plurality of second permanent magnets 4 are all projected onto the projection plane, integrating these structures into the same plane and making it easier to explain the structures and define the dimensional relationships.

[0075] In the rotor structure, a first permanent magnet 3 and a second permanent magnet 4 are arranged side by side, and the first permanent magnet 3 and the second permanent magnet 4 together provide magnetic lines of force to the motor, thereby increasing the output of the motor.

[0076] According to this rotor structure, the polarity arrangement order of the first permanent magnet 3 and the multiple second permanent magnets 4 along the counterclockwise direction is the first polarity 5, the third polarity 7, the second polarity 6 and the fourth polarity 8, among which the first polarity 5 and the third polarity 7 are the same, and the second polarity 6 and the fourth polarity 8 are the same. The magnetic field lines of the first polarity 5 and the second polarity 6 of the first permanent magnet 3 enter the second rotor core 2 along the axial direction, and the magnetic field lines of the third polarity 7 and the fourth polarity 8 of the second permanent magnet 4 enter the second rotor core 2 along the tangential direction or the radial direction. As a result of these two sets of magnetic field line directions interfering with each other on the second rotor core 2, both sets of magnetic field lines can enter the air gap, and can only enter the air gap, increasing the air gap magnetic flux density, effectively reducing the magnetic flux leakage at both ends of the second permanent magnet, improving the no-load flux linkage, effectively improving motor efficiency and torque density, and increasing the motor output.

[0077] In some embodiments, the polarity arrangement of the permanent magnets in the rotor structure will be described by taking the second permanent magnet 4 as an example, which is magnetized in the tangential direction.

[0078] In the above-described embodiment, the polarity of the first permanent magnet 3 refers to the polarity of the end of the first permanent magnet 3 facing the second rotor core 2, and the first polarity 5 and the second polarity 6 are opposite polarities. For example, when the first polarity 5 is an N pole, the second polarity 6 is an S pole. The polarity of the second permanent magnet 4 refers to the polarity of the side of the second permanent magnet 4 facing the second rotor core 2, and the polarities of the second permanent magnet 4 are assigned so that the third polarity 7 faces the polarity of the second rotor core 2 corresponding to the first polarity 5 of the first permanent magnet 3, and the fourth polarity 8 faces the polarity of the second rotor core 2 corresponding to the second polarity 6 of the first permanent magnet 3. The third polarity 7 of the second permanent magnet 4 is the same as the first polarity 5 of the first permanent magnet 3, and if the first polarity 5 is a north pole, the third polarity 7 is also a north pole; the fourth polarity 8 of the second permanent magnet 4 is the same as the second polarity 6 of the first permanent magnet 3, and if the second polarity 6 is a south pole, the fourth polarity 8 is also a south pole.

[0079] 4 and 11 show no-load flux linkage diagrams for motors using different polarity combinations. If the first polarity 5 is numbered 1, the second polarity 6 is numbered 2, the third polarity 7 is numbered 3, and the fourth polarity 8 is numbered 4, there are a total of eight combinations: 1324, 2314, 1314, 2324, 1423, 2413, 1413, and 2423. Of these, the no-load flux linkages for the sequences 1324 and 2413 are the largest, and the no-load flux linkages for the sequences 2314 and 1423 are the smallest.

[0080] 11, the polarity arrangement of the rotor structure is arranged counterclockwise in the order of first polarity 5, third polarity 7, second polarity 6, and fourth polarity 8, forming a combination of 1324 or 2413. In this case, an interference effect occurs in the magnetic field lines at both end faces of the second rotor core 2, maximizing the no-load flux linkage. If the polarity order is first polarity 5, third polarity 7, first polarity 5, and fourth polarity 8, or second polarity 6, third polarity 7, second polarity 6, and fourth polarity 8, ignoring the relative relationship between the first polarity 5 and the second polarity 6 in the axial direction, an interference effect occurs in the magnetic field lines at one end face of the second rotor core 2, and a divergence effect occurs in the magnetic field lines at the other end face, resulting in a 32.8% reduction in the no-load flux linkage. When the polarity order is the second polarity 6, the third polarity 7, the first polarity 5, and the fourth polarity 8, a divergence effect occurs in the magnetic field lines at both end faces of the second rotor core 2, and the no-load interlinkage magnetic flux is significantly reduced by 65.2%.

[0081] In some embodiments, the first permanent magnet 3 is divided into a plurality of magnetized areas along the circumferential direction, with two adjacent magnetized areas magnetized in opposite directions, and both circumferential sides of each magnetized area partially overlap with two adjacent second permanent magnets 4 in a plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2. The two adjacent second permanent magnets 4 are magnetized in opposite directions, and a magnetic field region is defined by each magnetized area and the two adjacent second permanent magnets 4, with the polarity of the side of the magnetized area facing the magnetic field region being the same as the polarity of the sides of the two adjacent second permanent magnets 4 facing the magnetic field region.

[0082] In this embodiment, of the multiple magnetized areas of the first permanent magnets 3 located at both ends of the second rotor core 2, two magnetized areas corresponding to the same magnetic field region have the same polarity facing the magnetic field region, and the two second permanent magnets 4 on both sides of the magnetic field region in the circumferential direction have the same polarity facing the magnetic field region, and the polarity of the magnetized areas facing the magnetic field region is also the same. This allows the magnetic field lines at both ends to be concentrated toward the intermediate magnetic field region, making the interference effect of the magnetic field lines in the magnetic field region more pronounced, maximizing the no-load magnetic flux linkage, effectively increasing the magnetic field strength of the motor, and improving the motor output.

[0083] In some embodiments, the second permanent magnets 4 have a linear structure and are arranged along the radial direction of the second rotor core 2. By having the second permanent magnets 4 have a linear structure and being arranged along the radial direction of the second rotor core 2, the second rotor core 2 can be divided into multiple sector-shaped sections along the circumferential direction, and the shape of the magnetic field region formed by the second rotor core 2 can be more closely matched with the shape of each magnetized area of ​​the first permanent magnets 3. In addition, the second permanent magnets 4 form both side walls of the magnetic field region, improving the compatibility between the magnetic field region and the structure of each permanent magnet, further optimizing the distribution and path design of the magnetic field lines, and more effectively utilizing the magnetic field lines to form the magnetic field, increasing the magnetic field strength and improving motor performance.

[0084] The second permanent magnet 4 may have other structures, such as a V-shape.

[0085] In some embodiments, the magnetized area of ​​the first permanent magnet 3 covers the same polarity area of ​​the adjacent second permanent magnet 4 on a first circumferential side and covers the same polarity area of ​​the adjacent second permanent magnet 4 on a second circumferential side.

[0086] In some embodiments, the magnetized areas of the first permanent magnet 3 can be spaced apart, i.e., not adjacent to each other, with a non-magnetized area between them. By placing a non-magnetized area between adjacent magnetized areas, the area of ​​the non-magnetized area can be adjusted to adjust the ratio between the magnetized and non-magnetized areas of the first permanent magnet, which can reduce the saturation of the motor, improve the utilization rate of the motor's no-load magnetic flux linkage, contribute to reducing losses, make it easier to magnetize the first permanent magnet, and reduce the cost of the permanent magnet.

[0087] Referring to Figure 5, in some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the deviation between the geometric center line of at least one pair of poles of the first permanent magnet 3 and the center line of the corresponding rotor magnetic field of the second rotor core 2 is 5° or less.

[0088] In some embodiments, the geometric centerline of at least one pair of poles of the first permanent magnet 3 overlaps the centerline of the rotor magnetic field of the corresponding second rotor core 2. By defining the geometric positions of at least some of the poles of the first permanent magnet 3, it is possible to reduce magnetic flux leakage due to divergence of the rotor magnetic field toward the rotor end face. In this embodiment, the geometric centerline of one magnetized area of ​​the first permanent magnet 3 is the centerline of the boundary lines on both sides of the magnetized area.

[0089] The center of the magnetic field generated in the second rotor core 2 by the second permanent magnet 4 is the center of the rotor magnetic field, and is the position where the magnetic field is strongest in the second rotor core 2. The center of the magnetic field of the magnetized area of ​​the first permanent magnet 3 is the geometric center of the magnetized area of ​​the first permanent magnet 3. If the angular deviation between the center lines of the two magnetic fields is too large, the interference effect of the two sets of magnetic field lines will be reduced, and the magnetic field of the second permanent magnet 4 will be formed to take the first permanent magnet 3 as its path and diverge at its ends, increasing magnetic flux leakage. When the center lines of the two magnetic fields are aligned, the interference effect of the two sets of magnetic field lines will be optimal and magnetic flux leakage will be minimized.

[0090] Experiments have shown that when the angular deviation between the geometric center line of one magnetized area of ​​the first permanent magnet 3 and the center line of the corresponding rotor magnetic field is 5°, the no-load flux linkage is 10% lower than when the angle is 0°, the current increases by 10.5%, and copper loss increases by 21%. Further increases in the angular deviation result in further increases in current and copper loss. Figure 12 shows the change in no-load flux linkage with the angular deviation between the two. When the angular deviation between the two exceeds 5°, the no-load flux linkage decreases more rapidly, indicating a further increase in magnetic flux leakage.

[0091] Referring to Figure 6, in some embodiments, within a projection plane projected along the axial direction of the second rotor core 2 onto the end face of the second rotor core 2, if the angle formed by the connecting line between the two end points of one pole of the first permanent magnet 3 closest to the outer circumference of the rotor and the center of the second rotor core 2 is α, and the angle formed by the connecting line between the two end points of the magnetic conductive portion of one pole of the second rotor core 2 closest to the outer circumference of the rotor and the center of the second rotor core 2 is β, then α / β≧1, and in some embodiments, 1<α / β≦1.62.

[0092] The magnetic field lines of the first permanent magnets 3 pass through the second rotor core 2 and enter the air gap, where they generate torque through interaction with the stator magnetic field. By specifying the relationship between α and β, it is possible to reduce magnetic flux leakage at the ends of the second permanent magnets 4 and improve the utilization of the first permanent magnets 3 and second permanent magnets 4.

[0093] Specifically, the magnetically conductive portion of the second rotor core 2 is a direct flow path for the magnetic field lines of the first permanent magnets 3, and if α / β is too large, many of the first permanent magnets 3 cannot come into direct contact with the second rotor core 2, resulting in no path for the magnetic field lines to flow and no contribution to the air gap magnetic flux density of the first permanent magnets 3 due to the absence of a flow path diameter, reducing the utilization rate of the first permanent magnets 3. If α / β is too small, the area over which the first permanent magnets 3 cover the end faces of the second rotor core 2 becomes small and the area of ​​the second permanent magnets 4 that is not covered by the first permanent magnets 3 becomes large, and the magnetic field lines of the uncovered second permanent magnets 4 are not interfered with by the magnetic field lines of the first permanent magnets 3, resulting in increased magnetic flux leakage at the ends and reducing the utilization rate of the second permanent magnets 4. Figure 13 shows the change curves of the utilization rates of the first permanent magnet and the second permanent magnet with α / β. As α / β increases, the magnetic field lines of the first permanent magnet 3 increase, and its utilization rate increases initially before beginning to decrease due to the limited diameter of the flow passage. As α / β increases, the utilization rate of the second permanent magnet also increases initially and then gradually stabilizes. For this reason, the range of α / β is selected taking into consideration the utilization rates of the first permanent magnet 3 and the second permanent magnet 4.

[0094] Within a projection plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, if the angle formed by the connecting line between the two end points of one pole of the first permanent magnet 3 closest to the rotor outer circumference and the rotor center is defined as α, and the angle formed by the connecting line between the two end points of one pole of the second permanent magnet 4 closest to the rotor outer circumference and the rotor center is defined as γ, then α / γ > 1, and in some embodiments, 2.0 ≦ α / γ ≦ 3.3.

[0095] By specifying the relationship between α and γ, we can reduce magnetic flux leakage at the ends of the second permanent magnet 4 while improving the utilization of the first permanent magnet 3 and the second permanent magnet 4. Specifically, if α / γ is too large, the utilization of the first permanent magnet 3 decreases. If α / γ is too small, magnetic flux leakage at the ends of the second permanent magnet 4 increases. Since magnetic flux leakage does not contribute to torque, the utilization of the second permanent magnet 4 also decreases. Figure 14 shows the change in the utilization of the first permanent magnet and the end magnetic flux leakage coefficient of the second permanent magnet as a function of α / γ. As α / γ increases, the utilization of the first permanent magnet initially increases and then decreases, while the end magnetic flux leakage coefficient of the second permanent magnet decreases and gradually stabilizes. Therefore, the range of α / γ is selected taking into account the utilization of the first permanent magnet and magnetic flux leakage at the ends of the second permanent magnet.

[0096] In some embodiments, when the polar arc angle of one pole of the second rotor core 2 is 360 / 2p in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, 360 / 2p / α≧1 holds, where p is the number of pole pairs of the second rotor core 2. In some embodiments, 1.3≧360 / 2p / α≧1 holds.

[0097] By defining the relationship between α and the rotor's pole arc, the end face space of the second rotor core 2 can be utilized to the maximum extent possible, allowing the placement of the first permanent magnets 3 and improving motor output while maintaining rotor unsaturation. Specifically, when 360 / 2p / α = 1, α is equal to the pole arc angle of one rotor pole, resulting in the highest utilization of the end face space of the second rotor core 2 and a correspondingly high rotor saturation. When 360 / 2p / α > 1, α is smaller than the pole arc angle of one pole of the second rotor core 2, resulting in a decrease in the utilization of the end face space of the second rotor core 2 and a corresponding decrease in rotor saturation.

[0098] Setting the value of 360 / 2p / α simultaneously adjusts the utilization rate of the end face space of the second rotor core 2 and the rotor saturation level. By defining the proportional range, an appropriate rotor saturation level can be selected, maximizing utilization of the end face space of the second rotor core 2. Figure 15 shows the change curves of the utilization rate of the end face space of the second rotor core 2 and the rotor saturation coefficient with 360 / 2p / α. As 360 / 2p / α increases, the utilization rate of the end face space of the second rotor core 2 and the rotor saturation coefficient also decrease. Note that a lower rotor saturation coefficient is not necessarily better; selecting an appropriate saturation coefficient allows for appropriate utilization of the core. A too low saturation coefficient results in excessive core volume, waste of material, and insufficient magnetic field lines, resulting in reduced motor output. In the present disclosure, a high utilization rate of the end face space of the second rotor core and moderate rotor saturation are preferable. When the motor's operating conditions differ, the value of 360 / 2p / α is selected taking both factors into consideration.

[0099] As shown in FIG. 8 , in some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the area of ​​one pole of the first permanent magnet 3 is s1, and the area of ​​one pole of the second rotor core 2 is s2. S1 / s2 ≥ 1 is satisfied. With this rotor structure, the magnetic field lines of the first permanent magnet pass through the second rotor core 2 and enter the air gap, generating torque through interaction with the stator magnetic field. By specifying the proportional relationship between the areas of one pole of the first permanent magnet 3 and the second rotor core 2 within the projection plane, the proportionality between the areas of one pole of the first permanent magnet 3 and the area of ​​one pole of the second rotor core 2 can be more appropriately set. This ensures the utilization rate of the first permanent magnet while improving the utilization rate of the second permanent magnet, reduces magnetic flux leakage at the rotor end, improves the overall utilization rate of the first permanent magnet 3 and the second permanent magnet 4, and further improves motor performance. In some embodiments, 1.05≦s1 / s2≦1.95. In some further embodiments, 1.25≦s1 / s2≦1.85.

[0100] Here, by specifying the areas of the first permanent magnets 3 and the second rotor core 2, a decrease in the utilization rates of the first permanent magnets 3 and the second permanent magnets 4 can be avoided. Figure 17 shows the change curves of the utilization rates of the first permanent magnets and the second permanent magnets with s1 / s2. The range of s1 / s2 is selected after taking into consideration the utilization rates of the first permanent magnets and the second permanent magnets in full detail.

[0101] As can be seen from the figure, when 1.25≦s1 / s2≦1.85, the overall utilization rate of the first permanent magnet 3 and the second permanent magnet 4 increases, the functions of the first permanent magnet 3 and the second permanent magnet 4 can be more fully exerted, and the operating performance of the motor can be improved.

[0102] In some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the area of ​​one pole of the first permanent magnet 3 is s1, the area of ​​one pole of the second permanent magnet 4 is s3, and in a cross section passing through the central axis of the second rotor core 2, the area of ​​one pole of the first permanent magnet 3 is s4, and the area of ​​one pole of the second permanent magnet 4 is s5, then 0.8*s3≦s1≦2.4*s5 and / or 0.3*s3≦s4≦0.8*s5.

[0103] By defining the area relationship between the first permanent magnet 3 and the second permanent magnet 4, the first permanent magnet 3 and the second permanent magnet 4 can improve motor output while ensuring a certain level of demagnetization resistance. Specifically, s1 and s4 determine the contribution of the first permanent magnet 3 to motor output and the demagnetization resistance of the first permanent magnet 3, respectively, while s5 and s3 determine the contribution of the second permanent magnet 4 to motor output and the demagnetization resistance of the second permanent magnet 4, respectively. By defining the relationship between s1 and s3, s1 can be maintained at a constant value, providing the motor with axial magnetic field lines. By defining the relationship between s1 and s5, the appropriate proportion of the flux linkage between the first permanent magnet 3 and the second permanent magnet 4 can be ensured, reducing the impact of saturation on the motor's no-load flux linkage utilization rate. By defining the relationship between s4 and s3, the demagnetization resistance of the first permanent magnet 3 and the demagnetization consistency between the first permanent magnet 3 and the second permanent magnet 4 can be ensured. By defining the relationship between s4 and s5, it is possible to avoid oversaturation of the motor due to excessive s4.

[0104] As shown in Figures 29 to 32, as s1 / s3 increases, the no-load flux linkage increases linearly, then the increase slows. The value of s1 / s3 is selected to correspond to the inflection point of the linear increase of the no-load flux linkage. As s1 / s5 increases, the no-load flux linkage utilization rate increases and then decreases. Once the motor reaches oversaturation, it suddenly decreases. The value of s1 / s5 is selected to correspond to the inflection point of the change in the no-load flux linkage utilization rate. As s4 / s3 increases, under the same demagnetizing current, the demagnetization rate of the first permanent magnet 3 decreases and the demagnetization rate of the second permanent magnet 4 increases slightly. The difference between the demagnetization rates of the first permanent magnet 3 and the second permanent magnet 4 tends to decrease, improving the demagnetization matching between the two. As s4 / s5 increases, the motor's saturation level increases. The value of s4 / s5 is selected to correspond to the inflection point of the motor's oversaturation.

[0105] In some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, if the area of ​​one pole of the first permanent magnet 3 is s1 and the length of a line connecting the central axis of the second rotor core 2 to any point on the outer circumference is j, then 1≦s1 / max(j)≦20. In some embodiments, 3≦s1 / max(j)≦16. In further embodiments, 5≦s1 / max(j)≦13.

[0106] By specifying the range of this ratio, the motor's magnetic flux collection effect can be strengthened and its output can be increased. Specifically, if s1 / max(j) is too small, s1 will be too small or max(j) will be too large, resulting in the following two situations. First, the s1 area will be too small, resulting in an insufficient coverage area for the ends of the second permanent magnet 4, increasing magnetic flux leakage at the ends of the second permanent magnet 4 and reducing the motor's magnetic flux collection effect. Second, the motor will have too many pole pairs, which is unfavorable for permanent magnet placement. If s1 / max(j) is too large, s1 will be too large or max(j) will be too small, reducing the motor's magnetic flux collection effect due to an insufficient number of pole pairs. FIG. 33 shows a curve of change in the magnetic flux collection effect coefficient of the motor with s1 / max(j). As s1 / max(j) increases, the magnetic flux collection effect coefficient initially increases and then decreases. In other words, both excessively large and excessively small s1 / max(j) cause a decrease in the magnetic flux collection effect of the motor.

[0107] In some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, if the area of ​​one pole of the first permanent magnet 3 is s1, the area of ​​one pole of the second rotor core 2 is s2, and the area of ​​one pole of the second permanent magnet 4 is s3, then 0.2≦s2 / (s1+s3)≦1. In some embodiments, 0.3≦s2 / (s1+s3)≦0.6.

[0108] By specifying this ratio range, the appropriate magnetic path area for the magnetic field lines of the first permanent magnet and the second permanent magnet can be ensured. This prevents an excessively small magnetic path area from increasing iron loss due to motor saturation, while also preventing excessive motor volume from wasting material. Figure 34 shows the change in iron loss and the utilization rate of the second rotor core as a function of s2 / (s1 + s3). As s2 / (s1 + s3) increases, the motor's saturation decreases, iron loss decreases, and once a certain level of saturation is reached, the change in iron loss gradually stabilizes. After the motor's saturation level decreases, the flow of magnetic field lines becomes smoother as the effective magnetic path area increases, and the utilization rate of the second rotor core increases. Once a certain level of saturation is reached, further increases in the magnetic path area cause the utilization rate of the second rotor core to begin to decrease.

[0109] 6 and 39 , in some embodiments, the thickness of the first permanent magnet 3 along the axial direction of the second rotor core 2 is defined as b. In a plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, the sum of angles formed by connecting lines between the two end points of each pole of the first permanent magnet 3 closest to the rotor outer circumference and the center of the second rotor core 2 is defined as α*2q, and the ratio of this angle to the circumferential angle of the second rotor core 2 is defined as a, where a=α*2q / 360, 2≦b / a≦6, where q is the number of pole pairs of the first permanent magnet 3. In some embodiments, 3≦b / a≦5.

[0110] By specifying the ratio of b to a, a consistent thickness of the first permanent magnet in the axial direction can be ensured, improving the demagnetization resistance of the first permanent magnet. Specifically, a = α * 2q / 360, where q is the number of pole pairs of the first permanent magnets 3. a represents the total pole arc coefficient of the first permanent magnets 3 and determines the range of the demagnetizing field that directly acts on the first permanent magnets 3. A smaller a reduces the range of the demagnetizing field acting on the first permanent magnets 3, and the axial thickness b required to ensure demagnetization resistance also decreases, and vice versa. Specifying the minimum value of b / a ensures the demagnetization resistance of the first permanent magnets 3. Specifying the maximum value of b / a avoids a decrease in the utilization rate of the first permanent magnets 3 due to waste, while ensuring the demagnetization resistance of the first permanent magnets 3. FIG. 16 shows the curves of the demagnetization rate and utilization rate of the first permanent magnet that change with b / a. As b / a increases, the demagnetization rate of the first permanent magnet at the same current decreases, and the trend of decrease becomes gentler, but the utilization rate of the first permanent magnet decreases, and the trend of decrease becomes more rapid. Therefore, the range of b / a is selected after taking into consideration the demagnetization resistance and utilization rate of the first permanent magnet in full.

[0111] In some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the area of ​​one pole of the first permanent magnet 3 is s1, and the thickness of the first permanent magnet 3 along the axial direction of the second rotor core 2 is b. Here, the unit of area s1 is mm. 2 and the unit of thickness b is mm.

[0112] In some embodiments, the relationship between s1 and b satisfies the dimensionless equation s1=-A*b+C, where A ranges from 5 to 20 and C ranges from 120 to 400.

[0113] By defining the relationship between s1 and b, the motor's saturation level can be reduced, the motor's no-load flux linkage utilization rate can be improved, and the motor's iron loss can be reduced. Specifically, s1 represents the magnetic supply area of ​​one pole of the first permanent magnet 3. If the first permanent magnet 3 has a large magnetic supply area, the rotor can reach an appropriate saturation level even with a small axial thickness b. However, further increasing the value of b can cause the rotor to become oversaturated, reducing the no-load flux linkage improvement effect and increasing iron loss, and vice versa. Therefore, s1 and b are negatively correlated. By defining the relationship curve between s1 and b, the motor's current and copper loss can be reduced while avoiding oversaturation and reducing core loss. When copper loss and iron loss are balanced, the motor's performance is optimized. Experiments have shown that when an appropriate b value is selected for a certain s1 value, the proportions of the motor's iron loss and copper loss are 52% and 48%, respectively, achieving a nearly balanced result. In this case, if the b value is increased by another 1 mm, the motor's iron loss increases by 10.2%, while the copper loss decreases by less than 1%, resulting in a deterioration in motor performance. Figure 35 shows the change in the motor's iron loss and copper loss as b increases for the same s1.

[0114] In some embodiments, within a projection plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, the sum of the angles formed by the connecting lines between the two end points of each pole of the first permanent magnet 3 closest to the outer circumference of the rotor and the center of the second rotor core 2 is α*2q, and the ratio of this angle to the circumferential angle of the second rotor core 2 is a, then a=α*2q / 360, 1.7≦a*b≦12.

[0115] In some embodiments, 2≦a*b≦10.

[0116] Specifying the multiplication relationship between a and b ensures that the first permanent magnets 3 occupy a certain angle on the second rotor core 2, increasing the motor's magnetic field strength and improving motor output. Specifically, a = α * 2q / 360, where q is the number of pole pairs of the first permanent magnets 3. a represents the total pole arc coefficient of the first permanent magnets 3 and determines the size of the magnetic supply area of ​​the first permanent magnets 3. If a is small, the magnetic supply area of ​​the first permanent magnets 3 becomes small, and the axial thickness b must be increased to achieve appropriate saturation, and vice versa. Specifying the minimum value of a * b ensures that the first permanent magnets 3 occupy a certain area on the second rotor core 2, increasing the rotor's magnetic field strength. Specifying the maximum value of a * b avoids waste of the first permanent magnets 3 while maintaining the rotor's magnetic field strength. FIG. 36 shows the change curves of the air gap magnetic flux density and the utilization rate of the first permanent magnet with a*b. As a*b increases, the air gap magnetic flux density increases, and when the magnetic path becomes saturated, the rate of increase in the air gap magnetic flux density gradually decreases, and the rate of decrease in the utilization rate of the first permanent magnet becomes faster.

[0117] In some embodiments, 0.2≦b / m≦2, where m is the thickness of the second permanent magnet 4 along the magnetization direction.

[0118] In some embodiments, 0.4≦b / m≦1.4.

[0119] By specifying the relationship between b and m, it is possible to ensure a certain level of demagnetization resistance and demagnetization consistency for the first permanent magnet 3 and the second permanent magnet 4. Specifically, the demagnetization resistance of the first permanent magnet 3 depends on its axial thickness b, and the demagnetization resistance of the second permanent magnet 4 depends on its magnetization direction thickness m. By specifying the minimum value of b / m, it is possible to ensure the demagnetization resistance of the first permanent magnet 3 and the second permanent magnet 4, and by specifying the range of possible values ​​for b / m, it is possible to ensure consistency in the demagnetization resistance of the first permanent magnet 3 and the second permanent magnet 4, and by specifying the maximum value of b / m, it is possible to reduce the cost of the permanent magnets while ensuring demagnetization resistance. Figure 18 shows the change curves of the demagnetization rate of the first permanent magnet and the demagnetization rate of the second permanent magnet with b / m under the same demagnetization current. As b / m increases, the demagnetization rate of the first permanent magnet decreases and the demagnetization rate of the second permanent magnet increases, and the demagnetization compatibility of the first permanent magnet and second permanent magnet improves at first and then deteriorates. Therefore, the range of b / m is selected taking into consideration the demagnetization resistance and demagnetization compatibility of the permanent magnets.

[0120] In some embodiments, when the thickness of the first rotor core 1 along the axial direction of the second rotor core 2 is c, 0.1≦c / b≦1 holds.

[0121] The value c is equal to or greater than the axial thickness of the single core punched piece of the second rotor core 2.

[0122] By specifying the relationship between b and c, an appropriate thickness ratio between the first rotor core 1 and the first permanent magnets 3 can be ensured, improving motor output and increasing utilization. Specifically, the magnetic field lines of the first permanent magnets 3 form a circuit by passing through the first rotor core 1 along its axial direction, and by installing the first rotor core 1 directly adjacent to the first permanent magnets 3, loss during circulation of the magnetic field lines of the first permanent magnets 3 can be avoided. Furthermore, the axial thickness of the first rotor core 1 determines the smoothness and saturation of the magnetic field flow path of the first permanent magnets 3. Specifying the minimum value of c / b ensures unsaturation of the magnetic path of the first permanent magnets 3 and improves the flux linkage of the first permanent magnets 3. On the other hand, specifying the maximum value of c / b increases the utilization rate of the first rotor core 1 and reduces costs. Figure 37 shows the curves of change in the saturation coefficient and utilization rate of the first rotor core with c / b. As c / b increases, both the saturation coefficient and utilization rate of the first rotor core 1 decrease, so the range of c / b is selected taking into consideration the saturation degree and cost of the first rotor core.

[0123] 7, in some embodiments, in a projection plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, the length of a connecting line between the center of the second rotor core 2 and the center of the radially inner edge of one pole of the first permanent magnet 3 is d, and the length of a connecting line between the center of the second rotor core 2 and the center of the radially outer edge of the first permanent magnet 3 is i, where 0.2≦d / max(i)≦0.8. In some embodiments, 0.3≦d / max(i)≦0.6.

[0124] Specifying the relationship of d / max(i) contributes to reducing the difficulty of assembling the motor and the difficulty of processing the first permanent magnet 3. Specifically, if d / max(i) is too small, the inside of the first permanent magnet 3 will be too small or the outside will be too large, increasing the difficulty of assembling it to the rotating shaft and stator. If d / max(i) is too large, the inside of the first permanent magnet 3 will be too large or the outside will be too small, making the distance between the inside and outside too small, increasing the difficulty of processing the first permanent magnet 3 and potentially making it impossible to process.

[0125] Referring to Figure 43, in some embodiments, within a projection plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, if the length of the connecting line between the central axis of the second rotor core 2 and the center of the edge of one pole of the first permanent magnet 3 closer to the outer circumference of the rotor is i, and the maximum value of the length of the connecting line between the central axis of the second rotor core 2 and each point on the outer circumference of the second rotor core 2 is max(j), then max(i)≦max(j).

[0126] In some embodiments, if the length of the connecting line between the central axis of the second rotor core 2 and the center of the edge of one pole of the second permanent magnet 4 that is closer to the outer circumference of the rotor is ii, then max(j)≧max(i)≧0.8*ii.

[0127] In some embodiments, max(j)≧max(i)≧0.95*ii.

[0128] By specifying the relationship between max(i), ii, and max(j), the length of the connecting line between the rotor center and the center of the first permanent magnet 3 near the rotor's outer circumference can be specified. This improves the contribution of the first permanent magnet 3 / second permanent magnet 4 to motor output while also reducing the difficulty of motor assembly. Specifically, magnetic flux leakage (top magnetic flux leakage) is likely to occur at the end of the second permanent magnet 4 near the rotor's outer circumference. The magnetic field lines of the first permanent magnet 3 interfere with the magnetic field lines of the second permanent magnet 4 here, cutting off the magnetic flux leakage path and reducing the top magnetic flux leakage. Specifying the relationship between max(i) and ii effectively reduces the top magnetic flux leakage of the second permanent magnet 4 within the range of action of the magnetic field lines of the first permanent magnet 3. Furthermore, specifying the relationship between max(j) and max(i) reduces the requirement for assembly precision of the first permanent magnet 3, thereby reducing the difficulty of motor assembly. Figure 44 shows the relationship curve between the top magnetic flux leakage coefficient of the second permanent magnet and max(i) / ii. As max(i) / ii increases, the top magnetic flux leakage coefficient of the second permanent magnet decreases, and there is a change in the downward trend. When max(i) / ii exceeds 0.8, the first inflection point occurs in the deceleration trend, and when max(i) / ii exceeds 0.95, the second inflection point occurs in the deceleration trend.

[0129] In some embodiments, if the length of the connecting line between the central axis of the second rotor core 2 and the center of the radially inner edge of one pole of the first permanent magnet 3 is d, and the length of the connecting line between the central axis of the second rotor core 2 and the center of the radially inner edge of the pole of the second permanent magnet 4 is f, then 0≦d / f≦2 holds.

[0130] In some embodiments, 0.8≦d / f≦1.6.

[0131] By specifying the proportional relationship of d / f, the length of the connecting line between the rotor center and the center of the first permanent magnet 3 closest to the rotor axis can be specified, thereby improving the utilization rate of the first permanent magnet 3 and the second permanent magnet 4. Specifically, magnetic flux leakage (bottom magnetic flux leakage) is likely to occur at the end of the second permanent magnet 4 closest to the rotor axis. The magnetic field lines of the first permanent magnet 3 interfere with the magnetic field lines of the second permanent magnet 4 at this point, cutting off the bottom magnetic flux leakage path and suppressing the bottom magnetic flux leakage of the second permanent magnet 4. Specifying the maximum value of d / f prevents the second permanent magnet 4 from significantly exceeding the effective range of the magnetic field lines of the first permanent magnet 3, resulting in an increase in bottom magnetic flux leakage and a decrease in the utilization rate of the second permanent magnet. Specifying the minimum value of d / f prevents the internal volume of the first permanent magnet 3 from being too small, thereby weakening the axial magnetic field lines, wasting material, and reducing the utilization rate. Figure 45 shows the relationship between the bottom magnetic flux leakage coefficient of the second permanent magnet, the utilization rate of the first permanent magnet, and d / f. As d / f increases, the bottom magnetic flux leakage coefficient of the second permanent magnet increases. When d / f is less than 1.6, the rate of increase slows down, and when d / f reaches 2, a second inflection point appears. As d / f increases, the utilization rate of the first permanent magnet initially increases, but then the reduction in the internal volume of the first permanent magnet affects the axial magnetic field lines, causing the utilization rate of the first permanent magnet to begin to decrease.

[0132] Referring to Figure 7, in some embodiments, within a projection plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, if the length of the connecting line between the central axis of the second rotor core 2 and the center of the edge of one pole of the first permanent magnet 3 closer to the rotor outer circumference is i, the length of the connecting line between the central axis of the second rotor core 2 and each point on the rotor outer circumference of the second rotor core 2 is j, and the length of the connecting line between the central axis of the second rotor core 2 and each point on the rotor outer circumference of the first rotor core 1 is h, then max(h)≦max(j) and / or min(h)≧0.8*max(i).

[0133] In some embodiments, 0.9≦min(h) / max(i)≦1.4.

[0134] In some embodiments, 1≦min(h) / max(i)≦1.3.

[0135] By specifying the dimensions of the first rotor core 1, it is possible to reduce magnetic flux leakage on the side of the first permanent magnet 3 closer to the rotor outer circumference while also easing the difficulty of motor assembly. Specifically, by specifying the maximum value of h, an air gap of a uniform width is formed between each rotor core (first rotor core 1, second rotor core 2) and the stator core 12, thereby reducing the difficulty of assembling the rotor to the stator. By specifying the minimum value of h, an effective magnetic path is ensured on all magnetic supply surfaces of the first permanent magnet 3, preventing magnetic flux leakage due to a lack of an effective main magnetic path in the axial direction. Figure 47 shows the relationship between no-load magnetic flux linkage and min(h) / max(i). As min(h) / max(i) increases, the no-load magnetic flux linkage increases, but the increase rate decreases. If min(h) / max(i) is less than 0.8, the magnetic flux leakage of the first permanent magnet increases, resulting in a small no-load flux linkage; if min(h) / max(i) exceeds 1.4, the magnetic field lines of the first permanent magnet pass completely through the magnetic path, resulting in almost no change in the no-load flux linkage.

[0136] In some embodiments, within a projection plane projected along the axial direction of the second rotor core 2 onto one end face of the second rotor core 2, if the length of the connecting line between the central axis of the second rotor core 2 and the center of the radially inner edge of one pole of the first permanent magnet 3 is d and the length of the connecting line between the central axis of the second rotor core 2 and each point on the radially inner edge of the first rotor core 1 is k, then max(k)≦d.

[0137] In some embodiments, 0.2≦max(k) / d≦1.

[0138] Specifying the dimensions of the first rotor core 1 reduces magnetic flux leakage on the side closer to the rotation axis of the first permanent magnet 3. Specifically, specifying the maximum value of k ensures an axial main magnetic path at the end of the first permanent magnet 3 closer to the rotation axis, preventing magnetic flux leakage due to a lack of the main magnetic path. Figure 48 shows the relationship curve between no-load flux linkage and max(k) / d. When max(k) / d is less than 0.2, the area of ​​the main magnetic path of the first permanent magnet 3 is large, resulting in a small improvement in no-load flux linkage. When max(k) / d exceeds 1, the flow path of the magnetic lines of force in the first permanent magnet 3 is restricted, resulting in a large reduction in no-load flux linkage.

[0139] In some embodiments, if the thickness of the first rotor core 1 along the axial direction of the motor is c and the thickness of the second permanent magnet 4 along the magnetization direction is m, then 0.1*m≦c≦m.

[0140] In some embodiments, 0.1*m≦c≦0.5*m.

[0141] By specifying the relationship between c and m, the magnetic flux density is not oversaturated, the utilization rate of the no-load magnetic linkage is reduced, and the motor output is not reduced, as would be the case if the thickness of the first rotor core 1 were too small. At the same time, the portion of the first rotor core 1 where iron loss occurs is minimized, thereby reducing motor loss. Figure 19 shows the change curves of the utilization rate of the no-load magnetic linkage and the iron loss of the motor with c / m. When c / m is less than 0.1, the utilization rate of the no-load magnetic linkage is low. When c / m is greater than 1, the iron loss increases significantly. When c / m is in the range of 0.1 to 1, the utilization rate of the no-load magnetic linkage improves and gradually stabilizes, and the increasing tendency of the iron loss is alleviated. When c / m is in the range of 0.1 to 0.5, the utilization rate of the no-load magnetic linkage increases almost linearly.

[0142] Referring to Figure 40, in some embodiments, a magnetic shielding groove 11 is installed on the side of the mounting groove closer to the central axis of the second rotor core 2, and in the projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the projection of the first permanent magnet 3 is configured to partially cover the projection of the magnetic shielding groove 11, i.e., the projection of the first permanent magnet 3 partially overlaps the projection of the magnetic shielding groove 11.

[0143] In some embodiments, the proportion of the coverage area of ​​the projection of the first permanent magnet 3 to the projection of the magnetic shielding groove 11 to the projection area of ​​the magnetic shielding groove 11 is 75% or less.

[0144] In some embodiments, the proportion of the coverage area of ​​the projection of the first permanent magnet 3 to the projection of the magnetic shielding groove 11 to the projection area of ​​the magnetic shielding groove 11 is 25% or less.

[0145] By defining the projection relationship between the first permanent magnets 3 and the magnetic shielding grooves 11, it is possible to reduce the saturation effect caused by the first permanent magnets 3 in the second rotor core 2 while improving the utilization rate of the first permanent magnets. Specifically, only some of the reinforcing ribs around the magnetic shielding grooves 11 have a magnetic conductive structure. If the first permanent magnets 3 cover the entire magnetic shielding grooves 11, the magnetic conductive area of ​​that portion will be small, resulting in a high degree of saturation. Furthermore, because the magnetic path area of ​​the first permanent magnets 3 covering that portion is limited, some of the flux linkage generated by the first permanent magnets 3 will become ineffective flux linkage due to a lack of magnetic path, reducing the utilization rate of the first permanent magnets.

[0146] FIG. 42 shows the no-load flux linkage and utilization rate of the first permanent magnet for different coating areas. Testing has shown that, compared to a 100% coating area, a 80% coating area reduces the no-load flux linkage by only 2.3%, while the cost of the first permanent magnet is reduced by 8.9%. Compared to a 100% coating area, a 70% coating area reduces the no-load flux linkage by 6.2%, while the cost of the first permanent magnet is reduced by 14.8%. Compared to a 100% coating area, a 20% coating area reduces the no-load flux linkage by 7.8%, while the cost of the first permanent magnet is reduced by 20.8%. In this disclosure, a coating area that reduces the no-load flux linkage and significantly reduces the cost of the permanent magnet is preferred. However, other coating areas proposed in this disclosure may also be selected to achieve high motor efficiency.

[0147] Referring to Figure 9, in some embodiments, within a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, if the minimum value of the radial width e of the first permanent magnet 3 is min(e) and the maximum value of the radial width g of the second permanent magnet 4 is max(g), then 0.5≦min(e) / max(g)≦2 holds.

[0148] In some embodiments, 0.6≦min(e) / max(g)≦1.6.

[0149] In some embodiments, 0.8≦min(e) / max(g)≦1.6.

[0150] By specifying the relationship between the radial widths of the first permanent magnet 3 and the second permanent magnet 4, it is possible to reduce magnetic flux leakage from the rotor and improve motor output and efficiency. Specifically, by specifying the range of min(e) / max(g), the second permanent magnet 4 can be positioned within the range of action of the magnetic field lines of the first permanent magnet 3, thereby reducing magnetic flux leakage from the rotor. Figure 49 shows the relationship curve between the motor magnetic flux leakage coefficient and min(e) / max(g). When min(e) / max(g) is less than 0.5, the magnetic flux leakage from the second permanent magnet 4 is large, resulting in an increased magnetic flux leakage coefficient. When min(e) / max(g) is greater than 2, the magnetic flux leakage coefficient remains almost unchanged due to the relatively good interference effect of the magnetic field lines between the first permanent magnet 3 and the second permanent magnet 4. When min(e) / max(g) is in the range of 0.5 to 2, the magnetic flux leakage coefficient decreases as min(e) / max(g) increases, and the decrease is particularly large in the range of 0.6 to 1.6.

[0151] In some embodiments, when the maximum value of the width o in the radial direction of the second rotor core 2 is max(o), max(e)≦max(o).

[0152] In some embodiments, 0.3≦max(e) / min(o)≦1.

[0153] In some embodiments, 0.4≦max(e) / max(o)≦0.95.

[0154] By defining the relationship between the radial widths of the first permanent magnets 3 and the second rotor core 2, the proportionality between the magnetic supply surface of the first permanent magnets 3 and the cross-sectional area of ​​its magnetic path can be optimized, reducing the degree of saturation of the second rotor core 2, reducing iron loss in the second rotor core 2, and improving motor efficiency. Figure 50 shows the change curve of the saturation coefficient of the second rotor core with max(e) / min(o) and max(e) / max(o). When max(e) / min(o) is less than 0.3 or max(e) / max(o) is less than 0.4, the saturation coefficient of the second rotor core is small and barely changes, resulting in a decrease in the motor's magnetic flux density and an impact on motor output. When max(e) / min(o) exceeds 1 or max(e) / max(o) exceeds 0.95, the increase in the saturation coefficient of the second rotor core becomes too large, increasing iron loss and degrading performance.

[0155] In some embodiments, 0.7≦min(l) / max(e)≦3 holds, where l is the radial width of the first rotor core 1.

[0156] In some embodiments, 1≦min(l) / max(e)≦2.

[0157] By defining the relationship between the radial widths of the first permanent magnets 3 and the first rotor core 1, the proportionality between the magnetic supply surface of the first permanent magnets 3 and the cross-sectional area of ​​its magnetic path can be optimized, reducing the degree of saturation of the first rotor core 1, reducing iron loss in the first rotor core 1, and improving motor efficiency. Figure 51 shows the change curve of the saturation coefficient of the first rotor core with min(l) / max(e). When min(l) / max(e) is less than 0.7, the saturation coefficient of the first rotor core is high and its iron loss increases. When min(l) / max(e) exceeds 3, the saturation coefficient of the first rotor core remains almost unchanged. When min(l) / max(e) is within the range of 0.7 to 3, the saturation coefficient of the first rotor core decreases as min(l) / max(e) increases, and the decrease is large within the range of 1 to 2.

[0158] Referring to Figures 38 and 46, in some embodiments, in a projection plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, if the area of ​​one pole of the first permanent magnet 3 is s1 and the height of the second rotor core 2 along the central axis direction is x, s1 and x are negatively correlated.

[0159] In some embodiments, s1=-B*x+D, where B ranges from 25 to 100 and D ranges from 400 to 1600.

[0160] By defining the relationship between s1 and x, we can achieve an appropriate ratio between the first permanent magnets 3 and the second rotor core 2, improve the utilization of the first permanent magnets 3 and the second rotor core 2, and reduce the motor's copper and iron losses. Specifically, s1 represents the magnetic supply area of ​​one pole of the first permanent magnet 3 and determines the strength of the axial magnetic field, while x determines the strength of the tangential / radial magnetic field. A large s1 allows the motor to reach optimal saturation even with a strong axial magnetic field and a weak tangential / radial magnetic field, and vice versa. In this case, further increasing s1 or x strengthens the axial or tangential / radial magnetic field, but the motor reaches saturation, resulting in a small reduction in copper loss and a significant increase in iron loss. This reduces the utilization of the first permanent magnets 3 and the second rotor core 2, resulting in reduced motor performance and material waste. Therefore, s1 and x are negatively correlated. Furthermore, by further specifying the relationship between s1 and x, the motor's copper loss and iron loss reach balance under different proportional axial and tangential magnetic fields, improving performance. Figure 53 shows the change curve of motor loss with s1 at a specific x. As s1 increases, the interlinkage magnetic flux provided to the first permanent magnet 3 increases and copper loss decreases until the motor reaches saturation, after which copper loss remains almost unchanged. As s1 increases, the motor's saturation level increases and iron loss increases. When copper loss and iron loss reach balance, s1 and x are optimally proportional.

[0161] In some embodiments, the diameters of the first permanent magnets 3 located on both ends of the second rotor core 2 are the same. By arranging them in this manner, the magnetic field lines of the first permanent magnets 3 on both end faces of the second rotor core 2 form a closed circuit, which increases the amount of magnetic flux in the motor while canceling out the axial forces at both ends of the rotor.

[0162] In some embodiments, if the number of pole pairs of the first permanent magnet 3 is q and the number of pole pairs of the second rotor core 2 is p, then q≦p. In some embodiments, q=p. By specifying the relationship between q and p, it is possible to improve the output torque of the motor while maximizing the utilization rate of the first permanent magnet.

[0163] In some embodiments, in a plane projected onto one end face of the second rotor core 2 along the axial direction of the second rotor core 2, the side edge of the first permanent magnet 3 closer to the outer circumference of the rotor is curved and / or straight, and / or the side wall of the first permanent magnet 3 closer to the central axis of the second rotor core 2 is curved and / or straight. This makes it possible to select the shape of the first permanent magnet 3 according to the space at the rotor end face and simplify the rotor structure, while also setting the shape of the first permanent magnet 3 based on processing requirements and reducing processing costs.

[0164] In some embodiments, the first rotor core 1 is provided with a balance weight structure for adjusting the dynamic balance of the motor, and the specific shape and material are not limited.

[0165] Referring to FIG. 41, according to an embodiment of the present disclosure, a motor includes the rotor structure described above.

[0166] The motor further includes a stator structure disposed radially outward of the rotor structure.

[0167] In some embodiments, the stator structure includes a stator core 12, and the outer diameter of the first permanent magnet 3 located at at least one end of the second rotor core 2 is smaller than the inner diameter of the stator core 12.

[0168] In some embodiments, the outer diameter of the first permanent magnet 3 located at at least one end of the second rotor core 2 is smaller than the maximum diameter of the outer diameters of the first rotor core 1 and the second rotor core 2.

[0169] By arranging them in this manner, as many first permanent magnets 3 as possible are brought into contact with the second rotor core 2, and the utilization rate of the first permanent magnets 3 can be improved.

[0170] 10 , in some embodiments, the motor includes a cover plate 9 and a rotating shaft 10, the cover plate 9 is attached to at least one end of the rotating shaft 10, and the minimum value of the outer diameter of the cover plate 9 is larger than the inner diameter of the stator core 12. When the distance between the cover plate 9 and the stator core 12 in the axial direction of the second rotor core 2 is E, 1.2y≦E≦2.3y holds.

[0171] The cover plate 9 may be a combination of the first rotor core 1 and the first permanent magnet 3, or may have other structures with axial magnetic flux characteristics. The cover plate 9 is installed at at least one end of the rotating shaft, and the axial magnetic flux generated by the cover plate 9 directly acts on the end faces of the stator core 12 and the second rotor core 2, improving the utilization rate of the core and effectively utilizing the winding ends at the end faces of the stator core 12, thereby improving the utilization rate of the windings. By specifying the axial distance between the cover plate 9 and the stator core 12, losses during the flow of axial magnetic flux can be reduced and the utilization rate of the cover plate 9 can be improved. Increasing the material utilization rate of the core, windings, and cover plate allows for a high torque density of the motor.

[0172] In some embodiments, the stator structure is fitted onto the outer periphery of the rotor structure, an air gap is formed between the stator structure and the rotor structure, and if the difference between the maximum outer diameter of the second rotor core 2 of the rotor structure and the maximum outer diameter of the first permanent magnet 3 is w, then w≧0.

[0173] In some embodiments, where the thickness of the air gap is δ, 0.5*min(δ)≦w≦14*min(δ). By specifying it in this way, the magnetic field lines generated by the permanent magnet can be made to enter the air gap as effective magnetic field lines while maintaining the air gap saturated, thereby improving the output torque of the motor.

[0174] In some embodiments, the stator structure includes a stator core 12 fitted over the outside of a second rotor core 2 of the rotor structure.

[0175] In some embodiments, x / y≦2 holds, where x is the height of the second rotor core 2 along the axial direction of the motor, and y is the height of the stator core 12 along the axial direction of the motor.

[0176] In some embodiments, 0.5≦x / y≦1.5.

[0177] In FIG. 41, x is the axial length of the second rotor core 2, y is the axial length of the stator core 12, and z is the axial length of the entire rotor structure of the motor.

[0178] By specifying the height ratio between the second rotor core 2 and the stator core 12, the utilization rates of the second rotor core 2 and the stator magnetic field can be improved, reducing motor costs and iron loss in the stator core 12, improving motor efficiency. Figure 52 shows the change curves of the utilization rates of the second rotor core and the stator magnetic field with x / y. When x / y exceeds 1.5, the reduction in the utilization rate of the second rotor core increases. When x / y is less than 0.5, the reduction in the utilization rate of the stator magnetic field also increases. When x / y exceeds 2, the second rotor core 2 is much higher than the stator core 12, preventing some of the rotor's magnetic field lines from entering the stator, resulting in a sharp decrease in the utilization rate of the rotor core.

[0179] In some embodiments, z / y≦4, where z is the total height of the rotor structure along the axial direction of the motor, and y is the height of the stator core 12 along the axial direction of the motor.

[0180] In some embodiments, 1.0≦z / y≦3.0.

[0181] By specifying the ratio between the heights of the stator core 12 and the rotor structure, the utilization rate of the stator core 12 can be improved, reducing motor costs, and the volume that generates iron loss in the stator portion can be reduced, thereby reducing iron loss. Figure 54 shows the relationship curve between the utilization rate of the stator core and z / y. As z / y increases, the utilization rate of the stator core increases and then decreases. When z / y exceeds 4, the ratio between the stacking heights of the rotor and stator core far exceeds the optimal ratio, so the reduction in the utilization rate of the stator core increases. When z / y is within the range of 1 to 3, the utilization rate of the stator core is high.

[0182] In some embodiments, if the height of the second rotor core 2 along the axial direction of the motor is x, the height of the stator core 12 along the axial direction of the motor is y, and the height of the first permanent magnet 3 along the axial direction of the motor is b, then 0.01x≦b≦0.7x and / or 0.015y≦b≦0.9y.

[0183] By specifying the relationship between the thickness of the first permanent magnets 3 and the height of the stator core 12 / rotor core, the degree of saturation of the stator and rotor cores due to the magnetic field lines of the first permanent magnets 3 can be reduced, thereby reducing iron loss in the motor. Figure 55 shows the change in the motor saturation coefficient with b / x and b / y. As b / x and b / y increase, the motor saturation coefficient increases. When b / x is less than 0.01 or b / y is less than 0.015, the motor saturation coefficient becomes too small, affecting motor output. When b / x exceeds 0.7 or b / y exceeds 0.9, the degree of saturation due to the magnetic field lines of the first permanent magnets increases, and the motor saturation coefficient increases sharply.

[0184] It should be noted that the terminology used herein is merely for the purpose of describing particular embodiments and is not intended to limit the exemplary embodiments of the present application. Unless otherwise specified, the singular forms used herein are intended to include the plural forms as well. It should also be understood that the use of the terms "comprises" and "comprises" herein indicates the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0185] It should be noted that the terms "first," "second," etc. in the specification, claims, and accompanying drawings of this application are used to distinguish between similar objects and are not necessarily used to describe a particular order or sequence. The data used herein may be interchangeable in some cases, and it should be understood that the embodiments of this application described herein may be implemented in an order different from that illustrated or described herein.

[0186] The above is merely a preferred embodiment of the present disclosure, and does not limit the present disclosure, and various modifications and variations are possible for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. that do not depart from the scope of the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure. [Explanation of symbols]

[0187] 1. First rotor core 2 Second rotor core 3 First permanent magnet 4 Second permanent magnet 5 First Polarity 6 Second Polarity 7. The Third Polarity 8 The Fourth Polarity 9 Cover Plate 10 Rotation axis 11 Magnetic shielding groove 12 stator core.

Claims

1. A rotor structure comprising: a first rotor core (1); a second rotor core (2) having a plurality of mounting grooves spaced apart along the circumferential direction; a first permanent magnet (3) that is axially magnetized and includes a first polarity and a second polarity; a plurality of second permanent magnets (4) including a third polarity (7) and a fourth polarity (8) and attached to the plurality of attachment grooves in a one-to-one correspondence; The first permanent magnets (3) are respectively installed at both ends of the second rotor core (2) along the axial direction, and the first rotor core (1) is installed on a side of the first permanent magnets (3) that is away from the second rotor core (2) along the axial direction, A rotor structure in which, in a projection plane projected onto one end face of the second rotor core (2) along the axial direction, the polarity arrangement order of the first permanent magnet (3) and the plurality of second permanent magnets (4) along the counterclockwise direction is a first polarity (5), a third polarity (7), a second polarity (6), and a fourth polarity (8), wherein the first polarity (5) and the third polarity (7) are the same, and the second polarity (6) and the fourth polarity (8) are the same.

2. the first permanent magnet (3) is divided into a plurality of magnetized areas along the circumferential direction, two adjacent magnetized areas are magnetized in opposite directions, and both sides of each magnetized area in the circumferential direction partially overlap with two adjacent second permanent magnets (4) within a projection plane in the axial direction; Two adjacent second permanent magnets (4) are magnetized in opposite directions, a magnetic field region is defined by each magnetized area and the two adjacent second permanent magnets (4), and the polarity of the side of the magnetized area facing the magnetic field region is the same as the polarity of the sides of the two adjacent second permanent magnets (4) facing the magnetic field region; 2. The rotor structure according to claim 1, wherein selectively, a magnetized area of ​​the first permanent magnet (3) covers a same polarity section of the adjacent second permanent magnet (4) on a first side in the circumferential direction and covers a same polarity section of the adjacent second permanent magnet (4) on a second side in the circumferential direction.

3. a deviation between a geometric center line of at least one pair of poles of the first permanent magnet and a center line of a rotor magnetic field of the second rotor core in a projection plane projected onto one end face of the second rotor core along the axial direction is 5° or less; 3. The rotor structure according to claim 1, wherein optionally, a geometric centerline of at least one pair of poles of the first permanent magnet (3) overlaps a centerline of a rotor magnetic field of a corresponding second rotor core (2).

4. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, an angle formed by a connecting line between two end points of one pole of the first permanent magnet (3) close to the rotor outer circumference and the center of the second rotor core (2) is defined as α, and an angle formed by a connecting line between two end points of a magnetically conductive portion of one pole of the second rotor core (2) close to the rotor outer circumference and the center of the second rotor core (2) is defined as β, where α / β≧1, and optionally 1<α / β≦1.62; and / or 4. The rotor structure according to claim 1, wherein, in a projection plane projected along the axial direction onto one end face of the second rotor core (2), an angle formed by a connecting line between two end points of one pole of the first permanent magnet (3) on the side closer to the rotor outer circumference and the center of the second rotor core (2) is defined as α, and an angle formed by a connecting line between two end points of one pole of the second permanent magnet (4) on the side closer to the rotor outer circumference and the center of the second rotor core (2) is defined as γ, where α / γ>1, and optionally 2.0≦α / γ≦3.

3.

5. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, an angle formed by a connecting line between two end points of one pole of the first permanent magnet (3) close to the rotor outer circumference and the center of the second rotor core (2) is defined as α, and a polar arc angle of one pole of the second rotor core (2) is defined as 360 / 2p, where p is the number of pole pairs of the second rotor core (2), and Optionally, a rotor structure according to any one of claims 1 to 4, wherein 1.3 > 360 / 2p / α > 1.

6. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, when the area of ​​one pole of the first permanent magnet (3) is s1 and the area of ​​one pole of the second rotor core (2) is s2, s1 / s2≧1, and optionally 1.05≦s1 / s2≦1.95; and / or In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, the area of ​​one pole of the first permanent magnet (3) is defined as s1, the area of ​​one pole of the second permanent magnet (4) is defined as s3, and in a cross section passing through the central axis of the second rotor core (2), the area of ​​one pole of the first permanent magnet (3) is defined as s4, and the area of ​​one pole of the second permanent magnet (4) is defined as s5, then at least one of 0.8*s3≦s1≦2.4*s5 and 0.3*s3≦s4≦0.8*s5 is satisfied; and / or In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, the area of ​​one pole of the first permanent magnet (3) is s1, and the length of a line connecting the central axis of the second rotor core (2) to an arbitrary point on the outer circumference is j, where 1≦s1 / max(j)≦20, and optionally 3≦s1 / max(j)≦16; and / or In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, when the area of ​​one pole of the first permanent magnet (3) is s1, the area of ​​one pole of the second rotor core (2) is s2, and the area of ​​one pole of the second permanent magnet (4) is s3, 0.2≦s2 / (s1+s3)≦1, and optionally 0.3≦s2 / (s1+s3)≦0.6; and / or 6. The rotor structure according to claim 1, wherein, in a projection plane projected onto one end face of the second rotor core along the axial direction, the area of ​​one pole of the first permanent magnet is s1 and the thickness of the first permanent magnet along the axial direction of the second rotor core is b, s1 and b have a negative correlation, and optionally, the relationship between s1 and b satisfies a dimensionless equation s1 = -A * b + C, where A is in the range of 5 to 20 and C is in the range of 120 to 400.

7. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, the sum of angles formed by connecting lines between two end points of each pole of the first permanent magnet (3) closer to the rotor outer circumference and the center of the second rotor core (2) is α*2q, and the ratio of the sum of angles to the circumferential angle of the second rotor core (2) is a, then a = α*2q / 360, and when the thickness of the first permanent magnet (3) along the axial direction of the second rotor core (2) is b, 2≦b / a≦6, where q is the number of pole pairs of the first permanent magnet (3), and / or 7. The rotor structure according to claim 1, wherein, in a projection plane projected onto one end face of the second rotor core (2) along the axial direction, the sum of angles formed by connecting lines connecting the two end points of each pole of the first permanent magnet (3) closer to the rotor outer circumference to the center of the second rotor core (2) is α*2q, and a is a ratio of the sum of angles to a circumferential angle of the second rotor core (2), where a=α*2q / 360, and b is a thickness of the first permanent magnet (3) along the axial direction of the second rotor core (2), where 1.7≦a*b≦12, where q is the number of pole pairs of the first permanent magnet (3), and optionally 2≦a*b≦10.

8. where b is the thickness of the first permanent magnet (3) along the axial direction and m is the thickness of the second permanent magnet (4) along the magnetization direction, 0.2≦b / m≦2, and optionally 0.4≦b / m≦1.4; and / or 8. The rotor structure according to claim 1, wherein, when the thickness of the first permanent magnet (3) along the axial direction is b and the thickness of the first rotor core (1) along the axial direction of the second rotor core (2) is c, c is equal to or greater than the thickness of a single punched piece of the second rotor core, and 0.1≦c / b≦1.

9. a magnetic shielding groove (11) is provided on a side of the mounting groove close to the central axis of the second rotor core (2), and a projection of the first permanent magnet (3) is configured to partially cover a projection of the magnetic shielding groove (11) within a projection plane projected onto one end face of the second rotor core (2) along the axial direction of the second rotor core (2); Optionally, the ratio of the coverage area of ​​the projection of the first permanent magnet (3) to the projection area of ​​the magnetic shielding groove (11) to the projection area of ​​the magnetic shielding groove (11) is 75% or less; 9. The rotor structure according to claim 1, wherein the ratio of the coverage area of ​​the projection of the first permanent magnet (3) to the projection area of ​​the magnetic shielding groove (11) to the projection area of ​​the magnetic shielding groove (11) is 25% or less.

10. Within a projection plane projected onto one end face of the second rotor core (2) along the axial direction, a length of a connecting line between the central axis of the second rotor core (2) and the center of an edge of one pole of the first permanent magnet (3) that is closer to the rotor outer circumference is defined as i, and a maximum value of the length of connecting lines between the central axis of the second rotor core (2) and each point on the rotor outer circumference of the second rotor core (2) is defined as max(j), then max(i)≦max(j), Alternatively, when the length of a connecting line between the central axis of the second rotor core (2) and the center of an edge of one pole of the second permanent magnet (4) that is closer to the outer circumference of the rotor is defined as ii in a projection plane projected onto one end face of the second rotor core (2) along the axial direction, max(j)≧max(i)≧0.8*ii; A rotor structure according to any one of claims 1 to 9, optionally with max(j) >= max(i) >= 0.95*ii.

11. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, a length of a connecting line between the central axis of the second rotor core (2) and the center of a radially inner edge of one pole of the first permanent magnet (3) is defined as d, and a length of a connecting line between the central axis of the second rotor core (2) and the center of an edge of one pole of the first permanent magnet (3) closer to the outer circumference of the rotor is defined as i, where 0.2≦d / max(i)≦0.8, and optionally 0.3≦d / max(i)≦0.6, and / or 11. The rotor structure according to claim 1, wherein, in a projection plane projected onto one end face of the second rotor core (2) along the axial direction, a length of a connecting line between the central axis of the second rotor core (2) and a center of a radially inner edge of one pole of the first permanent magnet (3) is d, and a length of a connecting line between the central axis of the second rotor core (2) and a center of a radially inner edge of one pole of the second permanent magnet (4) is f, where 0≦d / f≦2, and optionally 0.8≦d / f≦1.

6.

12. Within a projection plane projected onto one end face of the second rotor core (2) along the axial direction, the length of a connecting line between the central axis of the second rotor core (2) and the center of an edge of one pole of the first permanent magnet (3) that is closer to the rotor outer circumference is defined as i, the length of a connecting line between the central axis of the second rotor core (2) and each point on the rotor outer circumference of the second rotor core (2) is defined as j, and the length of a connecting line between the central axis of the second rotor core (2) and each point on the rotor outer circumference of the first rotor core (1) is defined as h, then max(h)≦max(j) and / or min(h)≧0.8*max(i) holds, A rotor structure according to any one of the preceding claims, optionally characterized in that 0.9≦min(h) / max(i)≦1.

4.

13. Within a projection plane projected onto one end face of the second rotor core (2) along the axial direction, a length of a connecting line between the central axis of the second rotor core (2) and the center of a radially inner edge of one pole of the first permanent magnet (3) is defined as d, and a length of a connecting line between the central axis of the second rotor core (2) and each point on the radially inner edge of the first rotor core (1) is defined as k, where max(k)≦d; A rotor structure according to any one of claims 1 to 12, optionally with 0.2≦max(k) / d≦1.

14. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, when the minimum value of the radial width e of the first permanent magnet (3) is min(e) and the maximum value of the radial width g of the second permanent magnet (4) is max(g), 0.5≦min(e) / max(g)≦2, and optionally 0.6≦min(e) / max(g)≦1.6; and / or In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, if the maximum value of the radial width e of the first permanent magnet (3) is max(e) and the maximum value of the radial width o of the second rotor core (2) is max(o), then max(e)≦max(o), and selectively, at least one of 0.3≦max(e) / min(o)≦1 and 0.4≦max(e) / max(o)≦0.95 holds true; and / or The rotor structure according to any one of claims 1 to 13, wherein, within a projection plane projected onto one end face of the second rotor core (2) along the axial direction, when the maximum value of the radial width e of the first permanent magnet (3) is max(e) and the minimum value of the radial width l of the first rotor core (1) is min(l), 0.7 ≦ min(l) / max(e) ≦ 3 is satisfied, and optionally 1 ≦ min(l) / max(e) ≦ 2 is satisfied.

15. In a projection plane projected onto one end face of the second rotor core (2) along the axial direction, if the area of ​​one pole of the first permanent magnet (3) is s1 and the height of the second rotor core (2) along the central axis direction is x, s1 and x have a negative correlation, and optionally, s1 = -B * x + D, where B is in the range of 25 to 100 and D is in the range of 400 to 1600, and / or 15. The rotor structure according to claim 1, wherein, when a thickness of the first rotor core (1) along the axial direction is c and a thickness of the second permanent magnet along the magnetization direction is m, 0.1*m≦c≦m, and optionally 0.1*m≦c≦0.5*m.

16. A motor comprising a stator structure and a rotor structure according to any one of claims 1 to 15, wherein the stator structure is fitted onto the outside of the rotor structure.

17. The stator structure includes a stator core (12), and the outer diameter of the first permanent magnet (3) located at at least one end of the second rotor core (2) is smaller than the inner diameter of the stator core (12), and / or 17. The motor according to claim 16, wherein the outer diameter of the first permanent magnet (3) located at at least one end of the second rotor core (2) is smaller than the maximum diameter among the outer diameters of the first rotor core (1) and the second rotor core (2).

18. An air gap is formed between the stator structure and the rotor structure, and when a difference between a maximum value of an outer diameter of a second rotor core (2) of the rotor structure and a maximum value of an outer diameter of the first permanent magnet (3) is w, w≧0 is satisfied; Optionally, the motor of claim 16 or 17, wherein 0.5*min(δ)≦w≦14*min(δ), where δ is the thickness of the air gap.

19. The stator structure includes a stator core (12), and when the height of the second rotor core (2) along the axial direction of the motor is x and the height of the stator core (12) along the axial direction of the motor is y, x / y≦2, and optionally 0.5≦x / y≦1.5; and / or 19. The motor of claim 16, wherein the stator structure includes a stator core (12), and wherein z / y≦4, and optionally 1.0≦z / y≦3.0, where z is a total height of the rotor structure along the axial direction of the motor, and y is a height of the stator core (12) along the axial direction of the motor.

20. The stator structure includes a stator core (12), and when the height of the second rotor core (2) along the axial direction of the motor is defined as x, the height of the stator core (12) along the axial direction of the motor is defined as y, and the height of the first permanent magnet (3) along the axial direction of the motor is defined as b, 0.01x≦b≦0.7x and / or 0.015y≦b≦0.9y are satisfied; and / or The motor according to any one of claims 16 to 19, further comprising a rotating shaft (10) and a cover plate (9) attached to at least one end of the rotating shaft (10), wherein a minimum value of an outer diameter of the cover plate (9) is larger than an inner diameter of the stator core (12), and where E is a distance between the cover plate (9) and the stator core (12) in the axial direction, 1.2y≦E≦2.3y.

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