Motor Rotor, Motor and Electric Vehicle

Abstract

The present application provides a motor rotor, a motor, and an electric vehicle. The motor rotor includes a rotor core. A V-shaped mounting groove and a U-shaped mounting groove are provided under each pole of the rotor core. Permanent magnets are provided in both the V-shaped mounting groove and the U-shaped mounting groove. In a cross-section perpendicular to the central axis of the rotor core, the included angle between the two inner sides of the V-shaped mounting groove is θ1. A first magnetic isolation groove is provided at one end of the V-shaped mounting groove, and a second magnetic isolation groove is provided at one end of the U-shaped mounting groove. The included angle between the two side edges of the first magnetic isolation groove close to the d-axis is α1, the included angle between the two side edges of the first magnetic isolation groove far from the d-axis is α2, the included angle between the two side edges of the second magnetic isolation groove close to the d-axis is α3, 1.4 ≤ k1 ≤ 1.6, 1.6 ≤ k2 ≤ 1.8, 2 ≤ k3 ≤ 2.2, and p is the number of pole pairs. According to the motor rotor of the present application, the harmonic content can be reduced, the torque ripple can be decreased, and the working performance of the motor can be improved.

Description

Technical Field

[0001] This application relates to the technical field of motors, and particularly to a motor rotor, a motor, and an electric vehicle. Background Art

[0002] Permanent magnet synchronous motors have characteristics such as high torque density, low manufacturing cost, and wide high-efficiency range, and are the first choice for drive motors of new energy vehicles such as pure electric, hybrid, and fuel cell vehicles.

[0003] However, current permanent magnet synchronous motors, due to the influence of the motor structure design, have problems of large harmonic content and large torque ripple, which affect the working performance of the motors. Summary of the Invention

[0004] Therefore, the technical problem to be solved by this application is to provide a motor rotor, a motor, and an electric vehicle, which can effectively reduce the harmonic content, reduce the torque ripple, and improve the working performance of the motor.

[0005] To solve the above problems, this application provides a motor rotor, including a rotor core. A V-shaped mounting groove and a U-shaped mounting groove are provided under each pole of the rotor core. The V-shaped mounting groove is located inside the U-shaped mounting groove. Magnets are provided in both the V-shaped mounting groove and the U-shaped mounting groove. In the cross-section perpendicular to the central axis of the rotor core, the included angle between the two inner sides of the V-shaped mounting groove is θ1. A first magnetic isolation groove is provided at one end of the V-shaped mounting groove close to the outer circle of the rotor, and a second magnetic isolation groove is provided at one end of the U-shaped mounting groove close to the outer circle of the rotor. The included angle between the two side edges of the first magnetic isolation groove close to the d-axis is α1, the included angle between the two side edges of the first magnetic isolation groove far from the d-axis is α2, and the included angle between the two side edges of the second magnetic isolation groove close to the d-axis is α3. 1.4 ≤ k1 ≤ 1.6, 1.6 ≤ k2 ≤ 1.8, 2 ≤ k3 ≤ 2.2, where p is the number of pole pairs.

[0006] Preferably, the width of the magnetic isolation bridge at the bottom of the V-shaped mounting groove is t1, and 0.5 mm ≤ t1 ≤ 0.8 mm.

[0007] Preferably, 40° ≤ θ1 = θ2 ≤ 50°, where θ2 is the included angle between the two side walls of the U-shaped mounting groove.

[0008] Preferably, the distance between the magnet in the V-shaped mounting groove and the magnet in the U-shaped mounting groove is L1. where d1 is the minimum distance between the magnet in the U-shaped mounting groove and the central axis of the rotor core, m ranges from 9.65 ≤ m ≤ 18.05, and θ2 is the included angle between the two inner sides of the U-shaped mounting groove.

[0009] Preferably, the distance between poles is L2, L2 = nL1, and n ranges from 0.6 ≤ n ≤ 0.8.

[0010] Preferably, the radius of the rotor core is R, where 50 mm ≤ R ≤ 55 mm. The minimum distance between the permanent magnet in the U-shaped mounting groove and the central axis of the rotor core is d1, where 20 mm ≤ d1 ≤ 25 mm. The minimum distance between the permanent magnet at the bottom of the U-shaped mounting groove and the bottom of the V-shaped mounting groove is d2, where 3 mm ≤ d2 ≤ 5 mm.

[0011] Preferably, the motor rotor has a skewed pole structure with a skewed pole angle of θ, where 3° ≤ θ ≤ 5°.

[0012] Preferably, the rotor core is provided with pin holes located within the V-shaped region of the V-shaped mounting groove.

[0013] According to another aspect of the present application, there is provided an electric motor including the above-described motor rotor.

[0014] According to another aspect of the present application, there is provided an electric vehicle including the above-described electric motor.

[0015] The motor rotor provided by the present application includes a rotor core. A V-shaped mounting groove and a U-shaped mounting groove are provided under each pole of the rotor core. The V-shaped mounting groove is located within the U-shaped mounting groove. Permanent magnets are provided in both the V-shaped mounting groove and the U-shaped mounting groove. In a cross-section perpendicular to the central axis of the rotor core, the included angle between the two inner sides of the V-shaped mounting groove is θ1. A first magnetic isolation groove is provided at one end of the V-shaped mounting groove close to the outer circumference of the rotor, and a second magnetic isolation groove is provided at one end of the U-shaped mounting groove close to the outer circumference of the rotor. The included angle between the two side edges of the first magnetic isolation groove close to the d-axis is α1, the included angle between the two side edges of the first magnetic isolation groove away from the d-axis is α2, and the included angle between the two side edges of the second magnetic isolation groove close to the d-axis is α3. 1.4 ≤ k1 ≤ 1.6, 1.6 ≤ k2 ≤ 1.8, 2 ≤ k3 ≤ 2.2, where p is the number of pole pairs. The motor rotor defines the pole structure by limiting the relationship between α1, α2, α3, and θ1, which can effectively reduce the harmonic content, reduce the torque ripple, and improve the operating performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a motor rotor according to an embodiment of the present application;

[0017] Figure 2 is a partially enlarged schematic structural diagram of a motor rotor according to an embodiment of the present application;

[0018] Figure 3 is a partially enlarged schematic structural diagram of a motor rotor according to an embodiment of the present application;

[0019] Figure 4 Schematic structural diagram of a motor rotor according to an embodiment of the present application;

[0020] Figure 5 is Figure 4 Enlarged structural diagram of part A of

[0021] Figure 6 Stereoscopic structural diagram of a motor rotor according to an embodiment of the present application;

[0022] Figure 7 Torque ripple simulation diagrams of a motor in the related art and a motor according to an embodiment of the present application.

[0023] The reference numerals are shown as:

[0024] 1, rotor core; 2, permanent magnet; 3, pin hole; 4, V-shaped mounting groove; 5, U-shaped mounting groove; 6, first magnetic isolation groove; 7, second magnetic isolation groove. Detailed implementation manners

[0025] Referring to Figures 1 to 7 As shown, according to the embodiment of the present application, the motor rotor includes a rotor core 1. A V-shaped mounting groove 4 and a U-shaped mounting groove 5 are provided under each pole of the rotor core 1. The V-shaped mounting groove 4 is located inside the U-shaped mounting groove 5. Permanent magnets 2 are provided in both the V-shaped mounting groove 4 and the U-shaped mounting groove 5. In a cross-section perpendicular to the central axis of the rotor core 1, the included angle between the two inner sides of the V-shaped mounting groove 4 is θ1. A first magnetic isolation groove 6 is provided at one end of the V-shaped mounting groove 4 close to the outer circle of the rotor. A second magnetic isolation groove 7 is provided at one end of the U-shaped mounting groove 5 close to the outer circle of the rotor. The included angle between the two side edges of the first magnetic isolation groove 6 close to the d-axis is α1. The included angle between the two side edges of the first magnetic isolation groove 6 far from the d-axis is α2. The included angle between the two side edges of the second magnetic isolation groove 7 close to the d-axis is α3, 1.4 ≤ k1 ≤ 1.6, 1.6 ≤ k2 ≤ 1.8, 2 ≤ k3 ≤ 2.2, where p is the number of pole pairs.

[0026] At the same time, the motor rotor also defines the magnetic pole structure by limiting the relationship between α1, α2, α3 and θ1. Thus, without changing the volume of the motor, the performance remains unchanged, the cost is lower, the manufacturing difficulty is lower, the harmonic content can be effectively reduced, the torque ripple can be reduced, and the working performance of the motor can be improved.

[0027] The above-mentioned permanent magnet is, for example, a ferrite permanent magnet.

[0028] By using ferrite permanent magnets to replace rare earth permanent magnets, the motor rotor can effectively reduce the cost and can utilize the characteristics of ferrite permanent magnets to improve the problem of demagnetization at high temperatures.

[0029] Since ferrite magnets are not easily demagnetized at high temperatures, the reliability of the motor at high temperatures is higher, which can bring a better experience to users.

[0030] In one embodiment, a shaft hole is provided at the center of the punching sheet body, and eight groups of UV-shaped mounting grooves are evenly distributed along the circumferential direction on the punching sheet body. Magnets 2 with dimensions slightly smaller than the mounting grooves are installed in the grooves. θ1 is the included angle of the V-shaped mounting groove 4, and θ2 is the included angle between the two side walls of the U-shaped mounting groove 5. As Figure 2 shown, θ1, θ2, L1, and L2 on the rotor punching sheet need to cooperate with each other and take an intermediate value to maximize the sum of the reluctance torque and the permanent magnet torque of the motor, so that the maximum torque can be obtained with the smallest volume. After a series of scanning verifications, the optimal solution is obtained, and the range of the optimal solution is that the included angle between the two V-shaped magnets is 40° ≤ θ1 = θ2 ≤ 50°.

[0031] In one embodiment, the distance between the magnet 2 in the V-shaped mounting groove 4 and the magnet 2 in the U-shaped mounting groove 5 is L1. Where d1 is the minimum distance between the magnet 2 in the U-shaped mounting groove 5 and the central axis of the rotor core 1, m ranges from 9.65 ≤ m ≤ 18.05, and θ2 is the included angle between the two inner sides of the U-shaped mounting groove 5.

[0032] The distance between poles is L2, and L2 = nL1, where n ranges from 0.6 ≤ n ≤ 0.8.

[0033] When the values of L1 and L2 meet the above standards, an optimal salient pole ratio is obtained, which maximizes the sum of the permanent magnet torque and the reluctance torque and can effectively improve the efficiency of the motor. The distance between poles here refers to the distance between two adjacent U-shaped mounting grooves between two adjacent poles.

[0034] In one embodiment, the width of the magnetic isolation bridge at the bottom of the V-shaped mounting groove 4 is t1, and 0.5 mm ≤ t1 ≤ 0.8 mm. The radius of the rotor core 1 is R, and 50 mm ≤ R ≤ 55 mm. The minimum distance between the magnet 2 in the U-shaped mounting groove 5 and the central axis of the rotor core 1 is d1, and 20 mm ≤ d1 ≤ 25 mm. The minimum distance between the magnet 2 at the bottom of the U-shaped mounting groove 5 and the bottom of the V-shaped mounting groove 4 is d2, and 3 mm ≤ d2 ≤ 5 mm.

[0035] t1 is the width of the magnetic isolation bridge between the V-shaped mounting groove 4 and the U-shaped mounting groove 5 at the bottom. Under the condition of meeting the process requirements and demagnetization requirements, the minimum value should be taken as much as possible to reduce magnetic leakage and increase the torque of the motor.

[0036] In one embodiment, in order to further reduce the torque ripple and harmonic content of the motor and reduce the vibration and noise of the motor, the entire rotor is skewed. In this embodiment, the entire rotor is divided into two segments, and there is a certain misalignment between the upper and lower segments of the rotor. The magnitude of the misalignment determines the magnitude of the torque ripple of the motor, but at the same time, part of the torque will be sacrificed. Therefore, an optimal solution must be sought between torque and torque ripple. The final scanned result is as follows: the skewing angle is 3° ≤ θ ≤ 5°.

[0037] The rotor core 1, mounting grooves, and permanent magnets 2 designed according to the above permanent magnet angle and gap parameters form a motor rotor with low cogging torque and small torque ripple.

[0038] In one embodiment, the UV-shaped mounting grooves are evenly distributed on the rotor core 1, and the angle per pole is 45°. The rotor core 1 is provided with pin holes 3, and the pin holes 3 are located in the V-shaped area of the V-shaped mounting grooves 4. After the rotor laminations of the rotor core 1 are stacked, they are fixed by pins installed in the pin holes 3.

[0039] In this embodiment, a pin hole 3 is provided in each V-shaped mounting groove 4. The pin hole 3 can be located on the d-axis or can be eccentrically arranged on one side relative to the d-axis.

[0040] The rotor core 1 has a central shaft hole, and axially extending protrusions are provided on the inner wall of the central shaft hole, which can be used as connection keys. Key grooves are provided on the rotating shaft and can cooperate with the connection keys to achieve synchronous rotation of the rotating shaft and the motor rotor.

[0041] Combined with reference to Figure 7 As shown, for the results of the motor rotor before and after optimization, it can be clearly seen that the entire torque ripple has been greatly reduced, but the torque has not decreased significantly. While reducing the cost, the vibration and noise of the motor have also been reduced.

[0042] The motor rotor structure of the present application is simple and low in cost. The composed motor has the remarkable characteristics of high power density, small vibration and noise, high saliency ratio, and small cogging torque and torque fluctuation, and is suitable for electric vehicle motors used in new energy vehicles.

[0043] According to an embodiment of the present application, the motor includes a motor rotor, and the motor rotor is the above-mentioned motor rotor.

[0044] According to an embodiment of the present application, an electric vehicle includes a motor, and the motor is the above-mentioned motor.

[0045] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above advantageous methods can be freely combined and superimposed.

[0046] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the technical principle of the present application, several improvements and variations can still be made, and these improvements and variations should also be regarded as within the protection scope of the present application.

Claims

1. A motor rotor, characterized in that, It includes a rotor core (1). A V-shaped mounting groove (4) and a U-shaped mounting groove (5) are provided under each pole of the rotor core (1). The V-shaped mounting groove (4) is located inside the U-shaped mounting groove (5). Permanent magnets (2) are provided in both the V-shaped mounting groove (4) and the U-shaped mounting groove (5). In a cross-section perpendicular to the central axis of the rotor core (1), the included angle between the two inner sides of the V-shaped mounting groove (4) is θ1. A first magnetic isolation groove (6) is provided at one end of the V-shaped mounting groove (4) close to the outer circle of the rotor. A second magnetic isolation groove (7) is provided at one end of the U-shaped mounting groove (5) close to the outer circle of the rotor. The included angle between the two side edges of the first magnetic isolation groove (6) close to the d-axis is α1. The included angle between the two side edges of the first magnetic isolation groove (6) away from the d-axis is α2. The included angle between the two side edges of the second magnetic isolation groove (7) close to the d-axis is α3. 1.4 ≤ k1 ≤ 1.6, 1.6 ≤ k2 ≤ 1.8, 2 ≤ k3 ≤ 2.2, 40° ≤ θ1 ≤ 50°, where p is the number of pole pairs.

2. The motor rotor according to claim 1, wherein The width of the magnetic isolation bridge at the bottom of the V-shaped mounting groove (4) is t1, where 0.5 mm ≤ t1 ≤ 0.8 mm.

3. The motor rotor according to claim 1, characterized in that, 40° ≤ θ1 = θ2 ≤ 50°, where θ2 is the included angle between the two side walls of the U-shaped mounting groove (5).

4. The motor rotor according to claim 3, characterized in that, The distance between the magnet (2) in the V-shaped mounting groove (4) and the magnet (2) in the U-shaped mounting groove (5) is L1. Where d1 is the minimum distance between the magnet (2) in the U-shaped mounting groove (5) and the central axis of the rotor core (1), the value of d1 is 20 mm ≤ d1 ≤ 25 mm, and the value of m is 9.65 ≤ m ≤ 18.

05.

5. The motor rotor according to claim 4, characterized in that, The distance between poles is L2, and L2 = nL1, where the value of n is 0.6 ≤ n ≤ 0.

8.

6. The motor rotor according to claim 1, characterized in that, The radius of the rotor core (1) is R, where the value of R is 50 mm ≤ R ≤ 55 mm. The minimum distance between the permanent magnet (2) in the U-shaped mounting groove (5) and the central axis of the rotor core (1) is d1, where the value of d1 is 20 mm ≤ d1 ≤ 25 mm. The minimum distance between the permanent magnet (2) at the bottom of the U-shaped mounting groove (5) and the bottom of the V-shaped mounting groove (4) is d2, where the value of d2 is 3 mm ≤ d2 ≤ 5 mm.

7. The motor rotor according to claim 1, characterized in that, The motor rotor is of an inclined pole structure, and the inclined pole angle is θ, where 3° ≤ θ ≤ 5°.

8. The motor rotor according to claim 1, characterized in that, The rotor core (1) is provided with a pin hole (3), and the pin hole (3) is located in the V-shaped area of the V-shaped mounting groove (4).

9. A motor, comprising a motor rotor, characterized in that, The motor rotor is the motor rotor according to any one of claims 1 to 8.

10. An electric vehicle, comprising a motor, characterized in that, The motor is the motor according to claim 9.

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