An embedded permanent magnet motor rotor and a permanent magnet motor

Abstract

The present invention discloses an embedded permanent magnet motor rotor and a permanent magnet motor, including an inner rotor core, wherein the inner rotor core and the yoke core are provided with corresponding symmetrical polygons or asymmetrical polygons or special shapes, facing and spaced at a certain distance, and isolated in the middle by insulating materials; the yoke core is evenly distributed with a number of magnet storage holes, and the magnet storage holes are embedded with permanent magnets; the yoke core is provided with a plurality of arc segments at the outer edge opposite to the permanent magnet, the main arc segment in the middle and the auxiliary arc segments on both sides; the outer side of the auxiliary arc segment extends away from the center line direction to the q axis direction, the adjacent auxiliary arc segments are connected, the two ends of the main arc segment are respectively connected to the auxiliary arc segment, and the main arc segment and the auxiliary arc segment form the arc of the sine wave peak. The present invention has a novel and reasonable structure, reduces electromagnetic torque pulsation, provides an ultra-quiet permanent magnet motor, reduces the motor shaft voltage, reduces the electro-corrosion of the bearing by high-voltage static electricity, and prolongs the service life of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motor structures, and in particular to an embedded permanent magnet motor rotor and a permanent magnet motor. Background Art

[0002] The rotor of a traditional embedded rotor permanent magnet motor adopts an integral iron core structure. The outer circle of the rotor is generally a full circle. The length of the stator inner teeth and the rotor circumferential air gap is equal. The embedded permanent magnet holes are built in the circumference and distributed tangentially close to the outer surface of the rotor core, which solves the problem of poor reliability during operation. However, it also brings the disadvantages of rectangular rotor back EMF waveform, large electromagnetic torque pulsation, and high electromagnetic noise. Moreover, the integral rotor core structure adopts a simple manufacturing process, but the induced voltage generated at the motor shaft end is also very high due to electromagnetic induction when the motor is running, which can easily cause electrocorrosion to the motor bearings during operation, affecting the service life of the motor. Summary of the invention

[0003] The purpose of the present invention is to solve the above technical problems and provide an embedded permanent magnet motor rotor and a permanent magnet motor.

[0004] In order to achieve the above technical objectives and meet the above technical requirements, the technical solution adopted by the present invention is: an embedded permanent magnet motor rotor and a permanent magnet motor, including an inner rotor core, characterized in that: the inner rotor core and the yoke core are provided with corresponding symmetrical polygons or asymmetrical polygons or special shapes, facing each other and spaced a certain distance apart, and isolated by insulating material in the middle; a number of magnet storage holes are evenly distributed on the yoke core, and permanent magnets are embedded in the magnet storage holes; the yoke core is provided with a plurality of arc segments on the outer edge opposite to the permanent magnet, a main arc segment in the middle and auxiliary arc segments on both sides; the outer side of the auxiliary arc segment extends away from the center line direction toward the q axis direction, adjacent auxiliary arc segments are connected, and the two ends of the main arc segment are respectively connected to the auxiliary arc segments, and the main arc segment and the auxiliary arc segment form the curvature of the peak of the sine wave.

[0005] Preferably, the main arc segments are symmetrically distributed relative to the center line of the permanent magnet, the center Q2 of the main arc segment is on the corresponding center line of the permanent magnet, and the center angle corresponding to the main arc segment is θ, θ=π / 4p, and p is the number of motor poles.

[0006] Preferably, the auxiliary arc segments are symmetrically arranged on both sides of the main arc segment.

[0007] Preferably: the inner rotor core and the circumscribed circle of the yoke core are concentric and insulated from each other, the insulation distance is d1, the radius of the circumscribed circle of the yoke core is set to r, and the determination principle of d1 is: 2≤d1≤r / 3.

[0008] Preferably, the vertex of the main arc segment is at the point where the circumscribed circle of the magnetic yoke core and the center line of the permanent magnet intersect, the center O2 of the main arc segment is on the center line of the permanent magnet and extends toward the center, and the radius r1 of the main arc segment is obtained by the following formula:

[0009] r1=

[0010] In the above formula, r is the radius of the circumscribed circle of the yoke core, P is the number of poles of the motor, and k is the air gap coefficient. k can be determined according to the size of the air gap between the stator and rotor, and is generally taken as 0.1mm~0.25mm.

[0011] Preferably, the center O3 of the auxiliary arc segment deviates from the center O2 of the main arc segment and is arranged in the same quadrant as the auxiliary arc segment. The width of the bridge between the poles is H. The coordinates of the center of the auxiliary arc segment are set to O3 (x, y). The determination of the coordinates of the center of the auxiliary arc segment is to ensure that the width of the bridge is t≤H≤2t, where t is the thickness of the steel plate material. The radius r2 of the auxiliary arc segments on both sides is obtained by the following formula:

[0012] r2=

[0013] In the above formula, x and y are the coordinates of the center O3 of the auxiliary arc segment, and the other parameters are the same as in formula r1.

[0014] Preferably: the main arc segment radius r1 < r.

[0015] Preferably: the radius of the auxiliary arc segment r2<r.

[0016] Preferably, the permanent magnets embedded in the magnetic yoke core are arranged alternately with N and S poles.

[0017] Compared with the traditional structure, the beneficial effects of the present invention are as follows: 1. The special-shaped outer edge of the rotor yoke core corresponds one-to-one to the relative embedded permanent magnets. The arc segments of the special-shaped outer edge are composed of a main arc segment located in the middle and symmetrical about the center line and auxiliary arc segments on both sides. By setting the outer circle of the rotor yoke core to multiple arc segments, a sinusoidally distributed air gap magnetic field is formed between the stator, which can effectively reduce electromagnetic torque pulsation, improve motor efficiency and motor operating performance, and reduce motor noise; 2. The insulating structure in which the inner rotor core and the yoke core are combined together by insulating material can reduce the voltage amplitude at the shaft end, reduce the electro-corrosion of the permanent magnet motor bearings caused by high-voltage static electricity, and extend the service life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 It is a cross-sectional schematic diagram of the present invention;

[0020] Figure 3It is a partial schematic diagram of the outer ring of the magnetic yoke core of the present invention;

[0021] Figure 4 It is a schematic diagram of the matching structure of the present invention and the stator;

[0022] In the figure: 1. stator, 2. rotor, 6. q axis, 7. circumscribed circle of yoke core, 9. yoke core, 91. main arc segment, 92. auxiliary arc segment, 10. permanent magnet, 12. insulating material, 13. inner rotor core. DETAILED DESCRIPTION

[0023] The present invention will be further described below.

[0024] Referring to the accompanying drawings, an embedded permanent magnet motor rotor and a permanent magnet motor include an inner rotor core 13, characterized in that: the inner rotor core 13 and the yoke core 9 are provided with corresponding symmetrical polygons or asymmetrical polygons or special shapes, facing each other and spaced a certain distance apart, and isolated in the middle by an insulating material 12; the permanent magnets 10 are placed in the magnet storage holes of the yoke core 9, the number of the permanent magnets 10 is related to the number of motor pole pairs, and the magnet storage holes are arranged tangentially and evenly distributed on the outer circle of the yoke core; the outer edge of the yoke core 9 opposite to the permanent magnet 10 is composed of a plurality of circular arc segments, including a main arc segment 91 in the middle and auxiliary arc segments 92 on both sides, the outer side of the auxiliary arc segment extends away from the center line direction toward the q axis direction, adjacent auxiliary arc segments 92 are connected, and the two ends of the main arc segment 91 are respectively connected to the auxiliary arc segments 92, the auxiliary arc segments 92 are symmetrically distributed relative to the center line of the permanent magnet 10, and the main arc segment 91 and the auxiliary arc segment 92 form the curvature of the sinusoidal wave peak.

[0025] In this preferred embodiment, the main arc segment 91 is symmetrically distributed relative to the center line of the permanent magnet 10. The center O2 of the main arc segment 91 is on the corresponding center line of the permanent magnet and is not concentric with the center O1 of the yoke core. The center angle range corresponding to the main arc segment is θ, θ=π / 4p (p is the number of motor poles).

[0026] In this preferred embodiment, the vertex of the main arc segment 91 is at the point where the circumscribed circle of the yoke core 11 and the center line of the permanent magnet intersect, the center of the circle is on the center line of the permanent magnet and extends toward the center of the yoke core 9 but is not concentric with the center of the yoke core 11.

[0027] By presetting the air gap coefficient k (which can be set according to the size of the air gap between the stator and the rotor, and is generally set to 0.1mm~0.25mm), the circumscribed circle radius of the yoke core 9 is r, and the main arc segment radius r1 can be calculated by the following formula, specifically:

[0028] r1=

[0029] In this preferred embodiment, the center O3 of the auxiliary arc segment (92) deviates from the center O2 of the main arc segment (91) and is arranged in the same quadrant as the auxiliary arc segment (92). The width of the bridge between the magnetic poles is H. The center coordinates of the auxiliary arc segment (92) are set to O3 (x, y). The determination of the center coordinates is to ensure that the width of the bridge is t≤H≤2t, where t is the thickness of the steel plate material. By presetting the center coordinates O3 (x, y) of the auxiliary arc segment, the radius r2 of the auxiliary arc segments on both sides can be calculated by the following formula, specifically:

[0030] r2=

[0031] After calculating the main arc segment radius r1 and the auxiliary arc segment radius r2 respectively, the main arc segment center O2 can be determined, and then according to the auxiliary arc segment center O3 set previously, the optimized rotor core shape that meets the sinusoidal air gap magnetic field requirements can be obtained.

[0032] In this preferred embodiment, the permanent magnet 10 is inserted into the magnet storage hole of the yoke core 9 in a manner in which the N and S poles are arranged alternately; the inner rotor core 13 is concentric with the outer ring yoke core 9 and is insulated from each other, and the insulation distance is d1. Assuming that the radius of the circumscribed circle of the yoke core 9 is r, when the inner rotor core 13 is placed concentrically with the yoke core 9, the principle for determining d1 is: 2≤d1≤r / 3. Such a distance setting can better suppress the amplitude of the shaft voltage generated, and the larger d1 is, the lower the amplitude of the shaft voltage is.

[0033] In this preferred embodiment, the inner rotor core 13 is concentric with the circumscribed circle of the yoke core 9, and the embedded permanent magnet motor rotor combines the inner rotor core 13, the yoke core 9 and a plurality of embedded permanent magnets 10 evenly distributed on the circumference of the yoke core through the insulating material 12 by injection molding or plastic sealing (but not limited to the above-mentioned process methods), thereby ensuring that the rotor structure is firm and the operation is reliable, reducing noise and vibration during operation, and extending the service life of the motor.

[0034] When the stator 1 and the rotor 2 cooperate with each other, a sinusoidally distributed air gap magnetic field is formed between the stator 1 and the rotor 2. When the motor is running, the current pulsation generated during commutation can be effectively reduced, and the electromagnetic torque pulsation can be reduced, thereby reducing the running noise of the motor. At the same time, the insulation structure of the inner rotor core 13 and the yoke core 9 also greatly reduces the motor shaft end voltage generated by electromagnetic induction, reduces the electro-corrosion phenomenon of the motor bearings, reduces the motor noise and prolongs the service life of the motor.

[0035] The above embodiments of the present invention are merely examples to clearly illustrate the present invention, but are not intended to limit the protection scope of the present invention. All equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. An embedded permanent magnet motor rotor, comprising an inner rotor core (13), characterized in that: An insulating material (12) is provided between the inner rotor core (13) and the yoke core (9); a plurality of magnet storage holes are evenly distributed on the yoke core (9), and permanent magnets (10) are embedded in the magnet storage holes; the yoke core (9) is provided with a plurality of arc segments at the outer edge opposite to the permanent magnets (10), a main arc segment (91) in the middle and auxiliary arc segments (92) on both sides; adjacent auxiliary arc segments (92) are connected, and both ends of the main arc segment (91) are respectively connected to the auxiliary arc segments (92), and the main arc segment (91) and the auxiliary arc segment (92) form an arc of a sine wave peak; The main arc segment (91) is symmetrically distributed relative to the center line of the permanent magnet (10), the center Q2 of the main arc segment (91) is on the corresponding center line of the permanent magnet (10), and the center angle corresponding to the main arc segment (91) is θ, θ=π / 4p, and p is the number of motor poles; The auxiliary arc segments (92) are symmetrically arranged on both sides of the main arc segment (91); The inner rotor core (13) and the circumscribed circle of the yoke core (9) are concentric and insulated from each other, and the insulation distance is d1. The radius of the circumscribed circle of the yoke core (9) is set to r, and the principle for determining d1 is: 2≤d1≤r / 3; The vertex of the main arc segment (91) is at the point where the circumscribed circle of the magnetic yoke core (9) and the center line of the permanent magnet (10) intersect, the center O2 of the main arc segment (91) is on the center line of the permanent magnet (10) and extends toward the center, and the radius r1 of the main arc segment is obtained by the following formula: ; k is the air gap coefficient; The center O3 of the auxiliary arc segment (92) deviates from the center O2 of the main arc segment (91) and is arranged in the same quadrant as the auxiliary arc segment (92). The width of the bridge between the magnetic poles is H. The center coordinates of the auxiliary arc segment (92) are set to O3 (x, y). The center coordinates are determined to ensure that the width of the bridge is t≤H≤2t, where t is the thickness of the steel plate material. The radius r2 of the auxiliary arc segments on both sides is obtained by the following formula: r2= ; The permanent magnets (10) embedded in the magnetic yoke core (9) are arranged alternately with N and S poles.

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