Spoke type rotor core and motor

Abstract

The utility model discloses a spoke type rotor iron core, which relates to the technical field of motors and is characterized in that a plurality of iron core shaping parts are fixed on 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 utility model, the outer circle of the rotor core is shaped, and uneven air gaps are formed on the periphery of the stator, so that the cogging torque and torque pulsation of the motor are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and further relates 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 magnetic flux and increase power.

[0004] In permanent magnet motors, improving motor performance typically requires higher rotor magnetic properties. Given limited structural constraints, the internal tangential rotor structure effectively increases the magnetic flux area and effective air gap flux compared to surface-mount and embedded radial rotors, thereby improving motor performance. However, the internal embedded tangential rotor structure's permanent magnets are limited by the radially designed magnetic isolation bridges, resulting in a certain amount of inter-pole magnetic leakage, which reduces 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. Utility Model Content

[0006] The utility model provides a spoke-type rotor core, which is reshaped at the outer circle to make the air gap uneven, thereby reducing the motor cogging torque and torque pulsation. The specific solution is as follows:

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

[0008] There is a spacing space between two adjacent core trimming parts for installing magnetic steel. 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 trimming portions of two adjacent poles, L2 is the thickness of the core trimming portions, and L1 / L2 is less than 0.67.

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

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

[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 utility model 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 portions are fixed to the outer periphery of the inner ring of the core in a circumferential array; each core shaping portion is independently arranged, with a space between adjacent core shaping portions; the outer peripheral surface of each core shaping portion is formed by splicing two arc surfaces, and the outer peripheral surface of the core shaping portion forms a depression toward the center of the circle. The depression design of the outer peripheral surface of the core shaping portion creates an uneven air gap, thereby reducing the cogging torque and torque pulsation of the motor. The present invention performs a shaping design on the outer periphery of the rotor core, forming an uneven air gap on the outer periphery of the stator, thereby reducing the cogging torque and torque pulsation of the motor. 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

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

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

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

[0023] Figure 4 is the axonometric drawing 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 ripple changing with R2 / R1;

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

[0029] Figure 10 is a graph showing the average torque changing with R2 / R1;

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

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

[0032] Figure 13 is a curve diagram showing the change of torque ripple with L1 / L2;

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

[0034] The diagram includes:

[0035] Iron core inner ring part 1, iron core shaping part 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 utility model 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-type rotor core and the motor of the present invention will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0038] Combine Figure 1 、 Figure 2 As shown, the utility model provides a spoke-type rotor core, including an inner core ring portion 1 and an iron core trimming portion 2. The inner core ring portion 1 and the iron core trimming portion 2 together constitute the entire iron core structure. The inner core ring portion 1 is a complete annular closed loop structure, and there is no gap in the circumferential direction of the inner core ring portion 1. There are multiple iron core trimming portions 2, and each iron core trimming portion 2 is independently provided. There is no relatively fixed connection between each iron core trimming portion 2. Several iron core trimming portions 2 are fixed to the outer periphery of the iron core inner ring portion 1 in a circumferential array, that is, each iron core trimming portion 2 is independently fixed to the iron core inner ring portion 1, and there is no direct connection between each iron core trimming portion 2. Combined Figure 1 The connection between the core trim portion 2 and the core inner ring 1 forms a magnetic isolation bridge. The width of the magnetic isolation bridge is smaller than the width of any position on the core trim portion 2. The core trim portions 2 are radially distributed with respect to the core inner ring 1, and the length of the core trim portions 2 extends in the radial direction of the core inner ring 1. The thickness of the core trim portions 2 is equal to that of the core inner ring 1.

[0039] Each core shaping part 2 is independently provided, each core shaping part 2 is not directly connected, there is a gap 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 space between the two adjacent core shaping parts 2 to position and fix the magnetic steel 7. A protruding block for positioning the magnetic steel 7 is provided on the outer periphery of the core inner ring part 1. Figure 3 As shown, after the magnet 7 is installed, the end of the magnet 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 magnet 7 away from the center of the circle respectively contact the bending angle of the core trimming part 2 to achieve positioning and cooperation.

[0040] Since the magnetic resistance of air is much greater than that of the iron core, the separation area formed between the iron core profiled portions 2 is mainly used to increase the magnetic circuit resistance, reduce the magnetic leakage of the rotor core, and thus improve 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 of the circle is the outer side, and the side close to the center of the circle is the inner side. The outer peripheral surface of the core shaping part 2 serves as the outer peripheral surface of the entire core. For the same core, the shapes and sizes of the core shaping parts 2 are the same. The core shaping parts 2 form 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 the outer peripheral surface of the core shaping part 2. Figure 5 、 Figure 6As shown, the structure of a complete core trimming portion 2 is shown. The two arc surfaces are distributed axially symmetrically, and the radius of each arc surface should be smaller than the radius of the entire core. A depression is formed at the intersection of the two arc surfaces, thereby forming a depression toward the center of the circle on the outer circumference of the core trimming portion 2. Each outer circumference of the core trimming portion 2 is provided with a corresponding depression. 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. Therefore, an uneven air gap is formed between the arc surface and the stator. Therefore, the air gap between the outer circumference of the entire core and the stator forms a periodically changing radial direction. The air gap spacing of the outer circumference of the entire core is not completely consistent, but varies in size. The utility model performs a trimming design on the outer circumference of the rotor to make the air gap 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 amplitude of the permeance harmonics and the air gap flux density, and inversely proportional to the least common multiple of the number of slots and the number of poles. The conventional rotor permeance 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 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 poles, and thus weakening the cogging torque.

[0043] On the basis of 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 modified portion 2 of each pole iron core is β, α / β=0.5; combined Figure 5 As shown, the outer peripheral surface of the core trimming portion 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. Connect O1-O and O2-O to form a straight line, forming a central angle ∠O1OO2. The corresponding center angle is α; the angle corresponding to each pole core trimming portion 2 is β. The entire rotor core is provided with N core trimming portions 2. The angle corresponding to each pole core trimming portion 2 is 360° / N. Figure 1 As shown, there are 14 pole core shaping portions 2, and β is 360° / 14=25.7°. The ratio of the two angles α / β=0.5 is a constant value.

[0044] Combine 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 、 Figure 9 、 Figure 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] Combine Figure 4 As shown, 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 traditional solutions, 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. In this case, the total magnetic path of the magnet from the outer diameter of the rotor is long, which will lead to increased magnetic leakage and reduced magnet utilization. Figure 11 、 Figure 12 As shown in the figure, under the same magnet cross-sectional area, the torque pulsation and average torque change curves with hpm / lpm. After simulation calculation, when hpm / lpm is between 0.24-0.36, the magnetic circuit of the magnet is shorter, the degree of magnetic leakage of the magnet is significantly reduced, the utilization rate of the magnet is increased, thereby improving the torque, and the torque pulsation is lower.

[0046] Combine Figure 6 As shown, L1 is the distance between the adjacent two-pole iron core modified portions 2, L2 is the thickness of the iron core modified portion 2, and L1 / L2 is less than 0.67. Figure 13 The figure shows the curve of torque pulsation changing with L1 / L2. After calculation, it is found that when L1 / L2 is less than 0.67, the torque pulsation is reduced, and since the core length is reduced, the leakage flux is reduced after the core is saturated, thereby increasing the utilization rate of the magnetic steel.

[0047] Combine Figure 1 、 Figure 2 As shown, in Option 1 of the present invention, a plurality of first lightening holes 3 are provided on the core inner ring portion 1. These first lightening holes 3 are arranged in a circumferential array. In the circumferential direction, the first lightening holes 3 are located between two core trimming portions 2. The first lightening holes 3 are polygonal with rounded corners. The outer periphery of the core inner ring portion 1 is provided with protrusions facing the outer periphery, with each first lightening hole 3 corresponding to one protrusion.

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

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

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

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

[0052] Based on 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, the present invention can reduce magnetic flux leakage and improve magnetic utilization when the rotor outer diameter is between 40mm-80mm and the number of rotor poles is 8, 10, 14, or 16. Furthermore, the specially modified rotor structure can reduce the motor's cogging torque and torque ripple. The shape and size of the weight-reducing holes can be adjusted or removed depending on the size of the rotor, and this part does not affect motor performance.

[0053] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily 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 is not limited to the embodiments shown herein but is intended to conform 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 circumferential array; There is a spacing space between two adjacent core trimming parts (2) for installing magnetic steel (7), and the outer peripheral surface of each core trimming part (2) is formed by splicing two arc surfaces, and the outer peripheral surface of the core trimming part (2) forms a depression toward 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 angle corresponding to 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 is less than 0.

67.

6. The spoke-type rotor core according to claim 1, characterized in that: A plurality of first weight-reducing holes (3) are provided on the core inner ring portion (1), and the first weight-reducing holes (3) are located between two 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 on both sides of the 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 according to any one of claims 1 to 9.

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