Rotor punching sheet with high reluctance ratio, rotor core, driving motor and vehicle

Abstract

The invention discloses a high reluctance ratio rotor punching sheet, which comprises a punching sheet main body and a magnetic pole unit arranged on the punching sheet main body, the magnetic pole unit comprises a first layer of permanent magnet slots, a second layer of permanent magnet slots and rectangular magnetic isolation holes, permanent magnets penetrate through the first layer of permanent magnet slots and the second layer of permanent magnet slots, and the rectangular magnetic isolation holes are formed in the first layer of permanent magnet slots and the second layer of permanent magnet slots. The first layer of permanent magnet slots comprises two permanent magnet slots, the second layer of permanent magnet slots comprises two permanent magnet slots, the two permanent magnet slots are distributed in a V shape, the first layer of permanent magnet slots and the rectangular magnetic isolation holes are located between the two permanent magnet slots, and the first layer of permanent magnet slots and the rectangular magnetic isolation holes are oppositely arranged. According to the rotor punching sheet with the high reluctance ratio, the salient pole ratio of a motor is improved through the optimal design of the magnetic poles, so that the reluctance torque of the motor is improved, the use amount of the rare earth permanent magnets is reduced, and the purpose of reducing the cost is achieved. The invention also discloses a rotor core, a driving motor and a vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric motors, and in particular, relates to a high magnetic reluctance ratio rotor punching sheet, a rotor core, a drive motor and a vehicle. Background Art

[0002] Internal rare earth permanent magnet synchronous motors are widely used in vehicle drive motors due to their high torque density, high power density and high efficiency. However, rare earth raw materials are expensive, resulting in high costs for rare earth permanent magnet motors.

[0003] Permanent magnet synchronous motors will induce high back electromotive force (BEMF) in the stator winding at high speeds, which may cause the controller to break down and limit the maximum speed of the motor. Therefore, under the premise of maintaining the same motor torque density, reducing the back electromotive force at high speeds has become an important indicator for motor design.

[0004] During motor operation, the interaction between the rotor magnetic field harmonics and the stator magnetic field harmonics of various orders will generate radial forces that vary with space and time, causing motor vibration and electromagnetic noise (NVH). In built-in permanent magnet synchronous motors, there is a common problem of high vibration noise due to the influence of stator slots.

[0005] For example, the patent document with publication number CN106230138A discloses a motor punching sheet, which includes a punching sheet body, a winding pile on the periphery of the punching sheet body and a magnetic strip at the connecting end of the punching sheet body. The technical solution disclosed in the patent document also cannot solve the technical problem described above. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a rotor punching sheet with a high magnetic resistance ratio, the purpose of which is to reduce costs.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a high magnetic resistance ratio rotor punching sheet, including a punching sheet body and a magnetic pole unit arranged on the punching sheet body, the magnetic pole unit includes a first layer of permanent magnet slots, a second layer of permanent magnet slots and a rectangular magnetic isolation hole, permanent magnets pass through the first layer of permanent magnet slots and the second layer of permanent magnet slots, the second layer of permanent magnet slots includes two permanent magnet slots, the two permanent magnet slots are distributed in a V shape, the first layer of permanent magnet slots and the rectangular magnetic isolation hole are located between the two permanent magnet slots, and the first layer of permanent magnet slots and the rectangular magnetic isolation hole are arranged relatively.

[0008] The first layer of permanent magnet slots is located between the rectangular magnetic isolation holes and the outer edge of the rotor punching sheet.

[0009] Auxiliary grooves are arranged on the outer edges of the rotor punching sheets.

[0010] The first layer of permanent magnet slots is an "I"-shaped permanent magnet slot structure, the second layer of permanent magnet slots is a "V"-shaped permanent magnet slot structure, and the permanent magnet slot structure is symmetrical about the direct axis.

[0011] The first layer of permanent magnet slots comprises a first magnetic isolation hole and a first permanent magnet slot segment. Two first magnetic isolation holes are provided. The first permanent magnet slot segment is located between the two first magnetic isolation holes. The permanent magnet passes through the first permanent magnet slot segment.

[0012] The second layer of permanent magnet slots comprises a second magnetic isolation hole, a third magnetic isolation hole and a second permanent magnet slot segment. The second permanent magnet slot segment is located between the second magnetic isolation hole and the third magnetic isolation hole, and the permanent magnet passes through the second permanent magnet slot segment.

[0013] The present invention also provides a rotor core, comprising the high magnetic resistance ratio rotor punching sheet.

[0014] The present invention also provides a driving motor, comprising the rotor core.

[0015] The present invention also provides a vehicle, comprising the driving motor.

[0016] The high reluctance ratio rotor punching sheet of the present invention improves the salient pole ratio of the motor through the optimized design of the magnetic pole, thereby improving its reluctance torque, reducing the amount of rare earth permanent magnets used, and achieving the purpose of reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] This specification includes the following drawings, which show the following contents:

[0018] Figure 1 is a schematic structural diagram of the rotor core of the first embodiment;

[0019] Figure 2 is a front view of the rotor core of the first embodiment;

[0020] Figure 3 is a front view of the magnetic pole unit of the first embodiment;

[0021] Figure 4 is a dimension marking diagram of the first layer of permanent magnet slots of the first embodiment;

[0022] Figure 5 is a dimension marking diagram of the second layer of permanent magnet slots of the first embodiment;

[0023] Figure 6 is a schematic diagram of a partial structure of a rotor punching sheet of the first embodiment;

[0024] Figure 7 is a front view of the rotor core of the second embodiment;

[0025] Figure 8is a front view of the magnetic pole unit of the second embodiment;

[0026] Fig. 9 is a dimension marking diagram of the first layer of permanent magnet slots of the second embodiment;

[0027] Fig.10 is a dimension marking diagram of the second layer of permanent magnet slots of the second embodiment;

[0028] Fig.11 is a dimension marking diagram of the magnetic pole unit of the second embodiment;

[0029] Fig.12 is a front view of the rotor core of the third embodiment;

[0030] Markings in the figure are: 10, rotor core; 200, rotor punching sheet; 210, punching sheet body; 220, axial hole; 222, axial hole core; 230, magnetic pole unit; 2310, first mounting slot; 2311, first magnetic isolation hole; 2312, first permanent magnet slot segment; 2313, first magnetic isolation bridge; 2314, first rotor yoke; 2320, second mounting slot; 2321, second magnetic isolation hole; 2322, third magnetic isolation hole; 2323, rectangular magnetic isolation hole; 2324, second permanent magnet slot segment; 2325, second magnetic isolation bridge; 2326, third magnetic isolation bridge; 2327, second rotor yoke; 2420, first layer of permanent magnet slots; 2440, second layer of permanent magnet slots; 250, auxiliary slots. DETAILED DESCRIPTION

[0031] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0032] It should be noted that, in the following embodiments, the “first”, “second” and “third” mentioned do not represent an absolute distinction in structure and / or function, nor do they represent a sequence of execution, but are merely for the convenience of description.

[0033] Embodiment 1

[0034] like Figures 1 to 6As shown, this embodiment provides a high magnetic resistance ratio rotor punching sheet, including a punching sheet body 210 and a plurality of magnetic pole units 230 arranged on the punching sheet body 210, and all magnetic pole units 230 are evenly distributed along the circumferential direction on the punching sheet body 210. The magnetic pole units 230 include a first layer of permanent magnet slots 2420, a second layer of permanent magnet slots 2440, and a rectangular magnetic isolation hole 2323, and permanent magnets pass through the first layer of permanent magnet slots 2420 and the second layer of permanent magnet slots 2440, and the second layer of permanent magnet slots 2440 include two permanent magnet slots, and the two permanent magnet slots are distributed in a V shape, and the first layer of permanent magnet slots 2420 and the rectangular magnetic isolation hole 2323 are located between the two permanent magnet slots, and the first layer of permanent magnet slots 2420 and the rectangular magnetic isolation hole 2323 are arranged relatively.

[0035] Specifically, if Figures 1 to 3 As shown, the first layer of permanent magnet slots 2420 is located between the rectangular magnetic isolation holes 2323 and the outer edge of the rotor punching. The first layer of permanent magnet slots 2420 is an "I" type permanent magnet slot structure, and the first layer of permanent magnet slots 2420 are symmetrical about the straight axis. The first layer of permanent magnet slots 2420 are close to the outer edge of the rotor punching, and the second layer of permanent magnet slots 2440 are located on the inner side of the first layer of permanent magnet slots 2420 away from the edge of the rotor punching, and the rectangular magnetic isolation holes 2323 are located in the middle of two symmetrically arranged permanent magnet slots of the second layer of permanent magnet slots 2440.

[0036] like Figures 1 to 3 As shown, the first layer of permanent magnet slots 2420 includes a first magnetic isolation hole 2311 and a first permanent magnet slot segment 2312. Two first magnetic isolation holes 2311 are provided, and the first permanent magnet slot segment 2312 is located between the two first magnetic isolation holes 2311. The permanent magnet passes through the first permanent magnet slot segment 2312, and the two first magnetic isolation holes 2311 are symmetrical about the straight axis.

[0037] like Figures 1 to 3 As shown, the second layer of permanent magnet slots 2440 includes two permanent magnet slots that are symmetrical about the straight axis and are spaced apart. The permanent magnet slots of the second layer of permanent magnet slots 2440 include a second magnetic isolation hole 2321, a third magnetic isolation hole 2322 and a second permanent magnet slot segment 2324. The second permanent magnet slot segment 2324 is located between the second magnetic isolation hole 2321 and the third magnetic isolation hole 2322, and the permanent magnet passes through the second permanent magnet slot segment 2324.

[0038] like Figures 1 to 3 As shown, the rectangular magnetic isolation hole 2323 is rectangular in shape and is symmetrical about the straight axis. The rectangular magnetic isolation hole 2323 is designed to be rectangular in order to ensure the size of the magnetic isolation bridge (to reduce magnetic leakage) and to ensure the strength requirements of the rotor.

[0039] like Figures 1 to 3 As shown, in this embodiment, a total of 12 magnetic pole units 230 are provided.

[0040] like Figures 1 to 3 As shown, the connection between the first layer of permanent magnet slots 2420 and the outer edge of the rotor punching is the first magnetic isolation bridge 2313, the connection between the second layer of permanent magnet slots 2440 and the outer edge of the rotor punching is the second magnetic isolation bridge 2325, the connection between the rectangular magnetic isolation hole 2323 and the magnetic isolation holes on both sides of the end of the second layer of permanent magnet slots 2440 is the third magnetic isolation bridge 2326, the two first magnetic isolation bridges 2313 are symmetrical about the direct axis, the two second magnetic isolation bridges 2325 are symmetrical about the direct axis, and the two third magnetic isolation bridges 2326 are symmetrical about the direct axis. The connection between the first layer of permanent magnet slots 2420 and the outer edge of the rotor punching is the first rotor yoke 2314, and the first rotor yoke 2314 is located between the two first magnetic isolation bridges 2313. The connection between the first layer of permanent magnet slots 2420 and the rectangular magnetic isolation hole 2323 is the second rotor yoke 2327, and the second rotor yoke 2327 is located between the two permanent magnet slots of the second layer of permanent magnet slots 2440.

[0041] like Figure 4 and Figure 5 As shown, the arc segment angle between the two first magnetic isolation bridges 2313 corresponding to the first layer of permanent magnet slots 2420 is the first pole arc angle θ1, the angle between the two permanent magnet slots of the second layer of permanent magnet slots 2440 is θ2, and the arc segment angle between the two second magnetic isolation bridges 2325 between the second layer of permanent magnet slots 2440 and the edge of the rotor punching is θ3.

[0042] The motor rotor core is composed of multiple stacked core sections (the number is M). The length L of each core section and the stacking height H of the rotor core have a relationship of: L=H / M. There is a certain skew angle γ between two adjacent core sections.

[0043] Define the slot angle: α1 = 360 / number of slots; set the rotor radius to R9, the first pole arc angle θ1 and the above motor slot angle α1 should satisfy:

[0044] 1.5α1≤θ1≤2.2α1.

[0045] The offset distance H1 of the first permanent magnet and the width W1 of the permanent magnet should satisfy:

[0046] 0.5W1≤H1≤0.75W1;

[0047] The second pole arc angle θ3 and the above motor slot angle α1 should satisfy:

[0048] 5α1≤θ3≤6α1.

[0049] The included angle θ2 of the second layer of permanent magnet slots 2440 should satisfy: 80°≤θ2≤100°.

[0050] The distance H2 between the second permanent magnet and the center of the rotor punching sheet should satisfy: 0.65R≤H2≤0.85R.

[0051] The sizes of the first permanent magnet embedded in the first layer of permanent magnet slots 2420 and the second permanent magnet embedded in the second layer of permanent magnet slots 2440 should satisfy:

[0052] 1.1≤L1 / L2≤1.3, 1≤W1 / W2≤1.2;

[0053] The thickness W2 of the second permanent magnet is greater than or equal to 2.7 mm and less than or equal to 5 mm; the width L2 of the second permanent magnet is greater than or equal to 9 mm and less than or equal to 16 mm.

[0054] The skew angles γ and α1 of two adjacent core sections should satisfy:

[0055] 0°≤γ≤α1*(M / 2-1) / (M / 2), M is an even number;

[0056] 0°≤γ≤α1*((M+1) / 2-1) / ((M+1) / 2), M is an odd number.

[0057] The implementation principle of this embodiment is as follows:

[0058] 1. To meet the requirements of reducing the no-load line back electromotive force (BEMF) and reducing costs, the length of the permanent magnet can be adjusted (reducing the amount of permanent magnet) to reduce the effective magnetic flux in the air gap;

[0059] 2. For the "V+1" type magnetic pole structure, the D-axis magnetic circuit is the magnetization direction of the permanent magnet, and the Q-axis (quadrature axis) magnetic circuit can be divided into: the part of the "V" close to the rotating shaft, the yoke part between the "V" and the "one", and the yoke part between the "one" and the rotor edge. Reasonable design of the rotor yoke, increasing the magnetic resistance on the D-axis (direct-axis) magnetic circuit, reducing the D-axis inductance, reducing the magnetic resistance of the Q-axis magnetic circuit, and increasing the Q-axis inductance can keep the motor at a high salient pole ratio (Lq / Ld), so that the motor can obtain a higher reluctance torque ratio and improve the torque density of the motor. At the same time, while ensuring the strength of the rotor, optimizing the size of the magnetic isolation bridge, reducing leakage magnetic flux, and improving the utilization rate of the permanent magnet can improve the torque output capacity.

[0060] In this embodiment, if Figure 4 As shown, the distance H1 between the first layer of permanent magnet slots 2420 and the outer edge of the rotor sheet is optimized. By increasing the thickness of the first rotor yoke 2314, the salient pole ratio is reduced by 1.18% and the torque is reduced by 1.62% compared with the optimization before. The efficiency ratio greater than 80% is increased by 2.4%. The relevant data before and after the optimization are shown in Table 1.

[0061] Table 1

[0062] Before optimization After optimization D-axis inductance 0.0377mH 0.03787 Q-axis inductance 0.09412mH 0.09343 Salient Pole Ratio 2.4966 2.4671 Peak torque 178.5Nm 175.6Nm >80% efficiency 82.71％ 85.11％

[0063] Biasing the permanent magnet will reduce the salient pole ratio and sacrifice a certain amount of torque, but the advantage is that it can increase the proportion of the motor's high-efficiency area. The highest efficiency area is distributed in the weak magnetic area after the inflection point, which improves the motor's weak magnetic performance. When the motor operates at high speed, it is more efficient and consumes less energy.

[0064] The high reluctance ratio rotor punching of the above structure has the following advantages:

[0065] 1. The output torque of the built-in permanent magnet synchronous motor is composed of permanent magnet torque and reluctance torque. By (optimizing the magnetic circuit design) increasing the salient pole ratio of the motor, the reluctance torque is increased, the amount of rare earth permanent magnets is reduced, and the cost is reduced;

[0066] 2. Reduce the effective magnetic flux in the air gap and achieve lower back EMF at the same torque density and maximum speed through the optimized design of the magnetic poles;

[0067] 3. Optimize the magnetic pole design so that the motor can still maintain certain salient pole characteristics under high-speed conditions and provide a certain magnetic resistance torque in the weak magnetic stage, thereby improving the motor output efficiency and reducing energy consumption;

[0068] 4. Rotor shaping, reasonable design of the rotor surface auxiliary slot 250, effectively reduce the harmonic content in the air gap magnetic field, improve the sinusoidality of the air gap magnetic density, improve the torque pulsation of the motor, reduce the radial electromagnetic force caused by harmonics, and improve NVH performance.

[0069] This embodiment also provides a rotor core, including a high magnetic resistance ratio rotor punching of the above structure.

[0070] This embodiment also provides a driving motor, including a rotor core of the above structure.

[0071] This embodiment also provides a vehicle, comprising a drive motor of the above structure.

[0072] Embodiment 2

[0073] like Figures 7 to 10 As shown, in this embodiment, an auxiliary groove 250 is provided on the outer edge of the rotor punching, a plurality of auxiliary grooves 250 are provided and all the auxiliary grooves 250 are evenly distributed along the circumferential direction, the angle between two adjacent auxiliary grooves 250 is θ4, and two adjacent auxiliary grooves 250 are symmetrical about the straight axis.

[0074] Assuming the radius of the auxiliary groove 250 is r, the angle θ4 between two adjacent auxiliary grooves 250 should satisfy:

[0075] 0.05R≤r≤0.15R, 1.2θ1≤θ4≤θ3.

[0076] The torque pulsation of the motor is related to the sinusoidality of the air gap magnetic field. The worse the sinusoidality of the motor's air gap magnetic flux, the higher the harmonic content, the greater the torque pulsation of the motor, and the higher the NVH risk. In addition to reasonably designing the geometric dimensions of the magnetic poles, shaping the rotor, and reasonably setting the auxiliary slots 250, the harmonic content in the air gap magnetic field can be effectively reduced, the sinusoidality of the air gap magnetic flux can be improved, the radial electromagnetic force can be reduced, and the NVH risk can be reduced.

[0077] After the auxiliary slot 250 is provided, the harmonic content of the air gap magnetic field can be greatly improved; at the same time, the rotor skew poles can further effectively weaken the harmonic content in the magnetic field and improve the vibration noise of the motor. Combining the two measures, the harmonic content of the no-load back EMF can be reduced to less than 1%.

[0078] like Figure 7 As shown, in this embodiment, a total of 12 magnetic pole units 230 are provided.

[0079] Embodiment 3

[0080] like Fig.11 As shown, in this embodiment, a total of ten magnetic pole units 230 are provided.

[0081] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A rotor punching sheet with a high magnetic resistance ratio, comprising a punching sheet body and a magnetic pole unit arranged on the punching sheet body, characterized in that: The magnetic pole unit includes a first layer of permanent magnet slots, a second layer of permanent magnet slots and rectangular magnetic isolation holes, the first layer of permanent magnet slots and the second layer of permanent magnet slots pass through permanent magnets, the second layer of permanent magnet slots includes two permanent magnet slots, the two permanent magnet slots are distributed in a V shape, the first layer of permanent magnet slots and the rectangular magnetic isolation holes are located between the two permanent magnet slots, and the first layer of permanent magnet slots and the rectangular magnetic isolation holes are arranged relatively.

2. The high reluctance ratio rotor punching sheet according to claim 1, characterized in that: The first layer of permanent magnet slots is located between the rectangular magnetic isolation holes and the outer edge of the rotor punching sheet.

3. The high reluctance ratio rotor punching sheet according to claim 1, characterized in that: Auxiliary grooves are arranged on the outer edges of the rotor punching sheets.

4. The high reluctance ratio rotor punching sheet according to any one of claims 1 to 3, characterized in that: The first layer of permanent magnet slots is an "I"-shaped permanent magnet slot structure, and the second layer of permanent magnet slots is a "V"-shaped permanent magnet slot structure, and the permanent magnet slot structure is symmetrical about the direct axis.

5. The high reluctance ratio rotor punching sheet according to any one of claims 1 to 3, characterized in that: The first layer of permanent magnet slots comprises a first magnetic isolation hole and a first permanent magnet slot segment. Two first magnetic isolation holes are provided. The first permanent magnet slot segment is located between the two first magnetic isolation holes. The permanent magnet passes through the first permanent magnet slot segment.

6. The high reluctance ratio rotor punching sheet according to any one of claims 1 to 3, characterized in that: The second layer of permanent magnet slots comprises a second magnetic isolation hole, a third magnetic isolation hole and a second permanent magnet slot segment. The second permanent magnet slot segment is located between the second magnetic isolation hole and the third magnetic isolation hole, and the permanent magnet passes through the second permanent magnet slot segment.

7. The rotor core is characterized by: It comprises the high magnetic reluctance ratio rotor punching sheet as described in any one of claims 1 to 6.

8. A driving motor, characterized in that: Comprising the rotor core as claimed in claim 7.

9. A vehicle, characterized in that: Includes the drive motor as described in claim 8.

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