Spoke type rotor core and motor

Abstract

The invention discloses a spoke type rotor iron core, and relates to the technical field of motors, and a plurality of iron core shaping parts are fixed at the periphery of an iron core inner ring part in a circumferential array; the iron core shaping parts are mutually independently arranged, an interval space exists between every two adjacent iron core shaping parts, the peripheral surface of each iron core shaping part is formed by splicing two sections of arc surfaces, and a recess facing the circle center direction is formed in the peripheral surface of each iron core shaping part. And therefore, the cogging torque and the torque pulsation of the motor are reduced. According to the invention, the outer circle of the rotor core is subjected to shape modification design, and non-uniform air gaps are formed in the periphery of the stator, so that the cogging torque and torque pulsation of the motor are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and further to a spoke-type rotor core and a motor. Background Art

[0002] Permanent magnet synchronous motors are widely used in rail transportation, aerospace, wind power generation and home appliances due to their simple structure, high efficiency, high power density and high torque density.

[0003] Traditional permanent magnet synchronous motors often use surface-mounted or built-in rotor structures. In order to improve the power density and torque density of the motor, permanent magnet motors often use spoke rotor structures to increase the air gap flux and increase power.

[0004] In permanent magnet motors, in order to improve motor performance, it is usually necessary to obtain higher rotor magnetic properties. Under limited structures, compared with surface-mounted and embedded radial rotors, the built-in tangential rotor structure can effectively increase the magnetic flux area, increase the effective air gap magnetic flux, and thus improve motor performance. However, the built-in embedded tangential structure permanent magnets are limited by the magnetic isolation bridge designed in the radial direction, and there is a certain amount of inter-pole leakage, which leads to a decrease in motor performance.

[0005] In the traditional structure, the motor cogging torque and torque pulsation are relatively large. For those skilled in the art, how to reduce the motor cogging torque and torque pulsation is a technical problem that needs to be solved at present. Summary of the invention

[0006] The present invention provides a spoke-type rotor core, which is profiled at the outer circumference to make the air gap uneven, thereby reducing the motor cogging torque and torque pulsation. The specific scheme is as follows:

[0007] A spoke-type rotor core comprises a core inner ring portion and a core shaping portion, wherein a plurality of core shaping portions are fixed to the outer periphery of the core inner ring portion in a circumferential array;

[0008] There is a spacing space for installing magnetic steel between two adjacent core trimming parts, and the outer peripheral surface of each core trimming part is formed by splicing two arc surfaces, and the outer peripheral surface of the core trimming part forms a depression toward the center of the circle.

[0009] Optionally, the included angle between the centers of the two arc surfaces and the center of the iron core is α, the angle corresponding to the iron core shaping portion of each pole is β, and α / β=0.5.

[0010] Optionally, R1 is the outer diameter of the circumscribed circle of the core, R2 is the diameter of the circle where the center of the core shaping portion is located, and the range of R2 / R1 is 0.78~0.83.

[0011] Optionally, hpm is the thickness of the magnetic steel, lpm is the length of the magnetic steel, and the range of hpm / lpm is 0.24~0.36.

[0012] Optionally, L1 is the distance between the core profiled portions of two adjacent poles, L2 is the thickness of the core profiled portion, and L1 / L2<0.67.

[0013] Optionally, a plurality of first weight-reducing holes are provided on the inner ring portion of the core, and the first weight-reducing holes are located between two of the core shaping portions.

[0014] Optionally, an air groove is provided in the magnetic isolation bridge portion between the inner ring portion of the core and the modified portion of the core.

[0015] Optionally, bumps are respectively provided on both sides of the core shaping portion.

[0016] Optionally, a second weight-reducing hole is provided on the core shaping portion.

[0017] The present invention also provides a motor, comprising any one of the spoke-type rotor cores described above.

[0018] The present invention provides a spoke-type rotor core, wherein a plurality of core shaping parts are fixed to the outer periphery of the inner ring of the core in a circumferential array; each core shaping part is independently arranged, and there is a spacing space between two adjacent core shaping parts. The outer peripheral surface of each core shaping part is formed by splicing two arc surfaces, and the outer peripheral surface of the core shaping part forms a depression toward the center of the circle. The depression design of the outer peripheral surface of the core shaping part makes the air gap uneven, thereby reducing the motor cogging torque and torque pulsation. The present invention performs shaping design at the outer circle of the rotor core, and forms an uneven air gap at the outer periphery of the stator, thereby reducing the motor cogging torque and torque pulsation. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0020] Figure 1 A front view of a first embodiment of a spoke-type rotor core provided by the present invention;

[0021] Figure 2 An axonometric view of a first embodiment of a spoke-type rotor core provided by the present invention;

[0022] Figure 3An axonometric view of the first embodiment of the spoke-type rotor core provided by the present invention with magnetic steel installed;

[0023] Figure 4 is the axonometric view of the magnetic steel;

[0024] Figure 5 for Figure 1 Schematic diagram of the partial structure of the center spoke rotor core;

[0025] Figure 6 for Figure 1 Schematic diagram of the partial structure of the center spoke rotor core;

[0026] Figure 7 A front view of a second embodiment of the spoke-type rotor core provided by the present invention;

[0027] Figure 8 It is a curve diagram of torque pulsation changing with R2 / R1;

[0028] Fig. 9 It is a graph showing the cogging torque changing with R2 / R1;

[0029] Fig.10 It is a curve diagram showing the average torque changing with R2 / R1;

[0030] Fig.11 is a graph showing the torque ripple changing with hpm / lpm;

[0031] Fig.12 is a graph showing average torque versus hpm / lpm;

[0032] Fig.13 It is a curve diagram of torque pulsation changing with L1 / L2;

[0033] Fig.14 This is a graph showing the average torque changing with electrical angle.

[0034] The figure includes:

[0035] Iron core inner ring portion 1, iron core shaping portion 2, first weight-reducing hole 3, air groove 4, protrusion 5, second weight-reducing hole 6, magnetic steel 7. DETAILED DESCRIPTION

[0036] The core of the present invention is to provide a spoke-type rotor core, and the core is reshaped at the outer circle to make the air gap uneven, thereby reducing the motor cogging torque and torque pulsation.

[0037] In order to enable those skilled in the art to better understand the technical solution of the present invention, the spoke rotor core and the motor of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0038] Combination Figure 1 , Figure 2 As shown, the present invention provides a spoke-type rotor core, including a core inner ring portion 1 and a core shaping portion 2. The core inner ring portion 1 and the core shaping portion 2 together constitute the entire core structure. The core inner ring portion 1 is a complete annular closed-loop structure, and there is no interval in the circumferential direction of the core inner ring portion 1. There are multiple core shaping portions 2, and each core shaping portion 2 is independently provided. There is no relatively fixed connection between each core shaping portion 2. Several core shaping portions 2 are fixed to the outer periphery of the core inner ring portion 1 in a circumferential array, that is, each core shaping portion 2 is independently fixed to the core inner ring portion 1, and there is no direct connection between each core shaping portion 2. Combined with Figure 1 The connection between the core trimming part 2 and the core inner ring part 1 is a magnetic isolation bridge, and the width of the magnetic isolation bridge is smaller than the width of any position of the core trimming part 2. Each core trimming part 2 is radially distributed with respect to the core inner ring part 1, and the length extension direction of the core trimming part 2 is along the radial direction of the core inner ring part 1. The thickness of the core trimming part 2 is equal to the thickness of the core inner ring part 1.

[0039] Each core shaping part 2 is independently arranged, each core shaping part 2 is not directly connected, there is a spacing space between two adjacent core shaping parts 2, and in the circumferential direction, each core shaping part 2 is spaced apart. Figure 3 As shown, the magnetic steel 7 is installed in the interval between two adjacent core trimming parts 2 to position and fix the magnetic steel 7. A protruding block for positioning the magnetic steel 7 is provided protruding outwardly from the outer circumference of the core inner ring part 1, such as Figure 3 As shown, after the magnetic steel 7 is installed, the end of the magnetic steel 7 close to the center of the circle contacts the protruding block to achieve positioning; a bending angle for positioning is set on the core trimming part 2, and the two top corners of the end of the magnetic steel 7 away from the center of the circle respectively contact the bending angles of the core trimming part 2 to achieve positioning cooperation.

[0040] Since the magnetic resistance of air is much greater than that of the core, the separation area formed between the core profiled portions 2 is mainly intended to increase the magnetic resistance of the magnetic circuit and reduce the magnetic leakage of the rotor core, thereby improving the utilization rate of the permanent magnets.

[0041] The length direction of the core shaping part 2 is distributed along the radial direction of the entire core. The side of the core shaping part 2 away from the center is the outer side, and the side close to the center is the inner side. The outer peripheral surface of the core shaping part 2 is the outer peripheral surface of the entire core. For the same core, each core shaping part 2 has the same shape and size. The core shaping part 2 forms a circumferential array distribution on the outer periphery of the core inner ring part 1. The outer peripheral surface of each core shaping part 2 is formed by splicing two arc surfaces, combined with Figure 5 , Figure 6As shown, the structure of a complete iron core trimming part 2 is shown, the two arc surfaces are distributed in an axisymmetric manner, and the radius of each arc surface should be smaller than the radius size of the entire iron core, and a depression is formed at the intersection of the two arc surfaces, so that a depression toward the center of the circle is formed on the outer peripheral surface of the iron core trimming part 2, and each outer peripheral surface of the iron core trimming part 2 is respectively provided with a corresponding depression, and the gap between the depression and the stator is larger, while the gap between the highest point of the arc surface convexity and the stator is smaller, so that an uneven air gap interval is formed between the arc surface and the stator, so that the air gap interval of the outer peripheral surface of the entire iron core is formed periodically along the radial direction between each position of the outer peripheral surface of the entire iron core and the stator, and the air gap interval of the outer peripheral surface of the entire iron core is not completely consistent, but is large and small. The present invention performs a trimming design at the outer circle of the rotor, so that the air gap is uneven, thereby reducing the motor cogging torque and torque pulsation.

[0042] According to the cogging torque formula, when the motor size parameters remain unchanged, the cogging torque is proportional to the permeance harmonic amplitude and the air gap flux density amplitude, and inversely proportional to the least common multiple of the number of slots and the number of poles. The permeance of the traditional rotor is evenly distributed along the circumference, which has little effect on the cogging torque. The present invention adopts a rotor shaping structure to make the rotor permeance unevenly distributed along the circumference, thereby reducing the amplitude of the permeance harmonics and reducing the cogging torque. In addition, the effect of the rotor shaping on the cogging torque is equivalent to increasing the number of rotor poles, increasing the least common multiple of the number of slots and the number of poles, thereby weakening the cogging torque.

[0043] Based on the above scheme, the included angle between the center of the two arc surfaces and the center of the iron core is α, the angle corresponding to the iron core modification portion 2 of each pole is β, and α / β=0.5; Figure 5 As shown, the outer peripheral surface of the core shaping part 2 is formed by splicing two arc segments. When viewed from the front, the two arc surfaces are two arc lines. The centers of the two arc lines are O1 and O2 respectively. The center of the entire rotor core is O. Straight lines are connected O1-O and O2-O to form a center angle ∠O1OO2. The corresponding center angle is α; the angle corresponding to each pole core shaping part 2 is β. The entire rotor core is provided with N core shaping parts 2. The angle corresponding to each pole core shaping part 2 is 360° / N. Figure 1 As shown, there are 14 pole core shaping parts 2, and β is 360° / 14=25.7°. The ratio of the above two angles α / β=0.5 is a constant value.

[0044] Combination Figure 5 As shown, R1 is the outer diameter of the circumscribed circle of the core, R2 is the diameter of the circle where the center of the core shaping portion 2 is located, R3 is the arc diameter, and the range of R2 / R1 is 0.78~0.83. Figure 8 , Fig. 9 , Fig.10The torque pulsation, cogging torque and average torque change curves with R2 / R1 shown. After simulation calculation, when R2 / R1 is between 0.78-0.83, the cogging torque and torque pulsation are low, and the torque loss is small.

[0045] Combination Figure 4 As shown in the figure, the magnet 7 is a rectangular parallelepiped structure, hpm is the thickness of the magnet 7, lpm is the length of the magnet 7, and the range of hpm / lpm is 0.24~0.36. In the traditional scheme, the magnet thickness is designed to be thin, and the magnet is generally slender. The magnet thickness (hpm) / magnet length (lpm) is generally less than 0.2. At this time, the total magnetic path of the magnet from the outer diameter of the rotor is long, which will lead to increased leakage and reduced magnet utilization. Fig.11 , Fig.12 As shown in the figure, under the same magnetic steel cross-sectional area, the torque pulsation and average torque change with hpm / lpm. After simulation calculation, when hpm / lpm is between 0.24-0.36, due to the shorter magnetic steel magnetic circuit, the magnetic steel leakage degree is significantly reduced, which increases the magnetic steel utilization rate, thereby improving the torque, and the torque pulsation is lower.

[0046] Combination Figure 6 As shown, L1 is the distance between the adjacent two-pole iron core trimming portions 2, L2 is the thickness of the iron core trimming portion 2, and L1 / L2<0.67. Fig.13 The figure shows the torque pulsation curve as L1 / L2 changes. After calculation, it is found that when L1 / L2 is less than 0.67, the torque pulsation decreases, and due to the reduction of the core length, the leakage magnetic flux decreases after the core is saturated, thereby increasing the utilization rate of the magnetic steel.

[0047] Combination Figure 1 , Figure 2 As shown, in one of the schemes 1 of the present invention, a plurality of first weight-reducing holes 3 are provided on the core inner ring 1, and the first weight-reducing holes 3 are arranged in a circumferential array. In the circumferential direction, the first weight-reducing holes 3 are located at the interval between the two core shaping parts 2, and the first weight-reducing holes 3 are rounded polygons. The outer periphery of the core inner ring 1 is provided with protrusions facing the outer periphery, and each first weight-reducing hole 3 corresponds to one protrusion.

[0048] exist Figure 1 , Figure 2 In the scheme shown, there is a solid structure for connecting and supporting each core shaping part 2 and the core inner ring part 1, combined with Figure 7As shown, in scheme 2 of the present invention, an air slot 4 is provided in the magnetic isolation bridge portion connecting the core inner ring portion 1 and the core trim portion 2, and two connecting and supporting physical structures are formed between each core trim portion 2 and the core inner ring portion 1; this structure changes the inner support method of the core trim portion 2, and uses two protruding structures to support the core trim portion 2, while changing the magnetic isolation bridge structure, adding air slots in the magnetic isolation bridge portion, further reducing magnetic leakage of the magnetic steel and improving the utilization rate of the magnetic steel. Fig.14 As shown, this solution can further improve the utilization rate of the magnetic steel and increase the torque.

[0049] Combination Figure 7 As shown, protrusions 5 are respectively provided on both sides of the core shaping portion 2, and the two protrusions 5 protrude along the circumferential direction respectively, which can play a positioning role for the installed magnetic steel.

[0050] Combination Figure 1 , Figure 2 , Figure 7 As shown, the core shaping portion 2 is provided with a second weight-reducing hole 6, and the second weight-reducing hole 6 can be a round hole.

[0051] The present invention also provides a motor, comprising the above-mentioned spoke-type rotor core, and the motor can achieve the same technical effect.

[0052] Combined with the above, it can be seen that when R2 / R1 is between 0.78-0.83, hpm / lpm is between 0.24-0.36, and L1 / L2 is less than 0.67, when the rotor outer diameter is between 40mm-80mm, and the number of rotor poles is 8 poles, 10 poles, 14 poles and 16 poles, the scheme of the present invention can reduce the magnetic leakage of the magnetic steel and improve the utilization rate of the magnetic steel; and through the special rotor shaping structure, the cogging torque and torque pulsation of the motor can be reduced. The shape and size of the weight-reducing hole part can be adjusted or removed with the size change, and this part does not affect the performance of the motor.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A spoke-type rotor core, characterized in that: It comprises an iron core inner ring portion (1) and an iron core shaping portion (2), wherein a plurality of the iron core shaping portions (2) are fixed to the outer periphery of the iron core inner ring portion (1) in a circular array; There is a spacing space between two adjacent core trimming portions (2) for installing the magnetic steel (7), the outer peripheral surface of each core trimming portion (2) is formed by splicing two arc surfaces, and the outer peripheral surface of the core trimming portion (2) forms a depression facing the center of the circle.

2. The spoke-type rotor core according to claim 1, characterized in that: The included angle between the centers of the two arc surfaces and the center of the iron core is α, and the corresponding angle of the iron core shaping portion (2) of each pole is β, and α / β=0.

5.

3. The spoke-type rotor core according to claim 1, characterized in that: R1 is the outer diameter of the circumscribed circle of the core, R2 is the diameter of the circle where the center of the core shaping portion (2) is located, and the range of R2 / R1 is 0.78-0.

83.

4. The spoke-type rotor core according to claim 1, characterized in that: hpm is the thickness of the magnetic steel (7), lpm is the length of the magnetic steel (7), and the range of hpm / lpm is 0.24-0.

36.

5. The spoke-type rotor core according to claim 1, characterized in that: L1 is the distance between the iron core trimming portions (2) of two adjacent poles, L2 is the thickness of the iron core trimming portion (2), and L1 / L2<0.

67.

6. The spoke-type rotor core according to claim 1, characterized in that: A plurality of first weight-reducing holes (3) are arranged on the core inner ring portion (1), and the first weight-reducing holes (3) are located between two of the core shaping portions (2).

7. The spoke-type rotor core according to claim 1, characterized in that: An air groove (4) is provided in the magnetic isolation bridge portion between the iron core inner ring portion (1) and the iron core shaping portion (2).

8. The spoke-type rotor core according to claim 7, characterized in that: Bumps (5) are respectively provided protrudingly on both sides of the iron core shaping portion (2).

9. The spoke-type rotor core according to any one of claims 1 to 8, characterized in that: A second weight-reducing hole (6) is provided on the iron core shaping portion (2).

10. A motor, characterized in that: The invention comprises the spoke-type rotor core as claimed in any one of claims 1 to 9.

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