Rotor assembly and motor

Abstract

The present disclosure provides a motor, comprising: a main permanent magnet and an auxiliary permanent magnet are provided on a rotor shaft, and the main permanent magnet and the auxiliary permanent magnet are arranged at intervals along the axial direction of the rotor shaft; a main stator core and an auxiliary stator core are arranged on the rotor shaft at axial intervals, the main stator core corresponds to the main permanent magnet in position, and the auxiliary stator core corresponds to the auxiliary permanent magnet in position; the main permanent magnet and the main stator core interact to generate a main cogging torque, the auxiliary stator core and the auxiliary permanent magnet interact to generate an auxiliary cogging torque, and the main cogging torque and the auxiliary cogging torque can cancel each other out. In the motor of the present disclosure, an auxiliary stator core and an auxiliary permanent magnet are installed on the rotor shaft, and the auxiliary stator core and the auxiliary permanent magnet can generate another cogging torque, which can cancel the cogging torque of the main stator core and the main permanent magnet of the motor, thereby greatly reducing the cogging torque and torque ripple of the motor, reducing the vibration and noise of the motor itself, and greatly improving the performance and stability of the motor during operation.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of electric motors, and particularly relates to a rotor assembly and an electric motor. Background Art

[0002] Cogging torque is the torque generated by the interaction between permanent magnets and the stator core when the windings of a permanent magnet motor are not energized. It is one of the unique problems of permanent magnet motors and a key problem that must be considered and solved in the design and manufacture of high-performance permanent magnet motors.

[0003] Cogging torque can cause the motor to vibrate and generate noise, resulting in speed fluctuations, and preventing the motor from running smoothly, thus affecting the performance of the motor. In variable speed drives, when the torque ripple frequency is consistent with the mechanical resonance frequency of the stator or rotor, the vibration and noise generated by cogging torque will be amplified. The existence of cogging torque also affects the low-speed performance in the motor speed control system and the high-precision positioning in the position control system. Therefore, the lower the cogging torque of the motor, the better the overall performance of the motor and the greater the market competitiveness of the motor. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present disclosure is that cogging torque causes the motor to vibrate and generate noise, etc., reducing the overall performance of the motor, and thus provides a rotor assembly and an electric motor.

[0005] To solve the above problems, the present disclosure provides an electric motor, including:

[0006] A rotor shaft, on which a main permanent magnet and an auxiliary permanent magnet are provided, and the main permanent magnet and the auxiliary permanent magnet are arranged at intervals along the axial direction of the rotor shaft;

[0007] A main stator core and an auxiliary stator core, which are arranged at intervals along the axial direction of the rotor shaft, the main stator core corresponding to the position of the main permanent magnet, and the auxiliary stator core corresponding to the position of the auxiliary permanent magnet;

[0008] The main permanent magnet and the main stator core interact to generate a main cogging torque, and the auxiliary stator core and the auxiliary permanent magnet interact to generate an auxiliary cogging torque, and the main cogging torque and the auxiliary cogging torque can cancel each other out.

[0009] The object of the present disclosure and the technical measures for solving its technical problems can be further realized by adopting the following technical measures.

[0010] In some embodiments, main tooth grooves are provided on the inner wall of the shaft hole of the main stator core, and auxiliary tooth grooves are provided on the inner wall of the shaft hole of the auxiliary stator core.

[0011] In some embodiments, along the axial direction of the rotor shaft, the projection of the main tooth grooves intersects with the projection of the auxiliary tooth grooves, or, along the axial direction of the rotor shaft, the projection of the main permanent magnets intersects with the projection of the auxiliary permanent magnets.

[0012] In some embodiments, the number of main tooth grooves is the same as the number of auxiliary tooth grooves, and / or the number of main permanent magnets is the same as the number of auxiliary permanent magnets.

[0013] In some embodiments, the main tooth grooves are circumferentially and uniformly arranged along the inner wall of the shaft hole of the main stator core, and / or the auxiliary tooth grooves are axially and uniformly arranged along the inner wall of the shaft hole of the auxiliary stator core.

[0014] In some embodiments, a main rotor core is provided on the rotor shaft, and the main permanent magnet is arranged on the main rotor core, and / or an auxiliary rotor core is provided on the rotor shaft, and the auxiliary permanent magnet is arranged on the auxiliary rotor core.

[0015] In some embodiments, the motor includes a brake, and the auxiliary stator core is the brake core.

[0016] In some embodiments, when the auxiliary tooth grooves are provided on the inner wall of the shaft hole of the auxiliary core, the auxiliary tooth grooves are provided on the inner wall of the shaft hole of the brake core.

[0017] In some embodiments, the auxiliary permanent magnet can also be a magnetic ring, and the number of poles of the magnetic ring is the same as that of the main permanent magnet.

[0018] In some embodiments, the main tooth grooves are skewed grooves, and / or the main permanent magnets are skewed poles, and / or the auxiliary tooth grooves are skewed grooves, and / or the auxiliary permanent magnets are skewed poles.

[0019] The motor provided by the present disclosure has at least the following beneficial effects:

[0020] For the motor provided by the present disclosure, aiming at the problem that the cogging torque generated by the interaction between the main stator core and the main permanent magnet of the permanent magnet motor reduces the performance of the motor, an auxiliary stator core and an auxiliary permanent magnet are installed on the rotor shaft. The auxiliary stator core and the auxiliary permanent magnet can generate another cogging torque, which can offset the cogging torque of the main stator core and the main permanent magnet of the motor, thereby greatly reducing the cogging torque and torque ripple of the motor, reducing the vibration and noise of the motor itself, and greatly improving the performance and stability of the motor during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the motor according to an embodiment of the present disclosure;

[0022] Figure 2 is a schematic structural diagram of the rotor shaft according to an embodiment of the present disclosure;

[0023] Figure 3 is Figure 2 the sectional view taken along line A-A in

[0024] Figure 4 is Figure 2 the sectional view taken along line B-B in

[0025] Figure 5 A cross-sectional view of the main stator core of the embodiment of the present disclosure;

[0026] Figure 6 A cross-sectional view of the auxiliary stator core of the embodiment of the present disclosure;

[0027] Figure 7 A waveform diagram of the main cogging torque and the auxiliary cogging torque of the embodiment of the present disclosure.

[0028] The reference numerals are represented as:

[0029] 1. Rotor shaft; 2. Main permanent magnet; 3. Auxiliary permanent magnet; 4. Main stator core; 5. Auxiliary stator core; 6. Main tooth slot; 7. Auxiliary tooth slot; 8. Main rotor core; 9. Brake. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the present disclosure clearer, the technical solutions of the present disclosure will be clearly and completely described below in conjunction with specific embodiments of the present disclosure and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without making creative efforts shall fall within the scope of protection of the present disclosure.

[0031] Combined with Figures 1 to 7 As shown, this embodiment provides a motor, including: a rotor shaft 1, on which a main permanent magnet 2 and an auxiliary permanent magnet 3 are provided, and the main permanent magnet 2 and the auxiliary permanent magnet 3 are arranged at intervals along the axial direction of the rotor shaft 1; a main stator core 4 and an auxiliary stator core 5, the main stator core 4 and the auxiliary stator core 5 are arranged at intervals axially on the rotor shaft 1, the main stator core 4 corresponds to the main permanent magnet 2 in position, and the auxiliary stator core 5 corresponds to the auxiliary permanent magnet 3 in position; the main permanent magnet 2 and the main stator core 4 interact to generate a main cogging torque, the auxiliary stator core 5 and the auxiliary permanent magnet 3 interact to generate an auxiliary cogging torque, and the main cogging torque and the auxiliary cogging torque can cancel each other out.

[0032] For the motor of the present disclosure, aiming at the problem that the cogging torque generated by the interaction between the main stator core 4 and the main permanent magnet 2 of the permanent magnet motor reduces the performance of the motor, an auxiliary stator core 5 and an auxiliary permanent magnet 3 are installed on the rotor shaft 1. The auxiliary stator core 5 and the auxiliary permanent magnet 3 can generate another cogging torque, which can cancel the cogging torque of the main stator core 4 and the main permanent magnet 2 of the motor, thereby greatly reducing the cogging torque and torque ripple of the motor, reducing the vibration and noise of the motor itself, and greatly improving the performance and stability of the motor during operation.

[0033] In some embodiments, since the cogging torque of the motor is related to the teeth and slots of the motor stator and exhibits a regular pulsating characteristic, main teeth and slots 6 are provided on the inner wall of the shaft hole of the main stator core 4, and auxiliary teeth and slots 7 are provided on the inner wall of the shaft hole of the auxiliary stator core 5. The auxiliary teeth and slots 7 corresponding to the main teeth and slots 6 are machined on the auxiliary stator core 5, so that the auxiliary cogging torque generates a corresponding pulsating characteristic, achieving a better cancellation effect.

[0034] In some embodiments, in order to make the main cogging torque and the auxiliary cogging torque have opposite pulsating directions and achieve the best cancellation effect, that is, as Figure 7 shown, when the rotor shaft 1 rotates to the peak of the main cogging torque, the auxiliary cogging torque is exactly at the trough, and the cogging torque and torque pulsation are smaller. Therefore, along the axial direction of the rotor shaft 1, the projections of the main teeth and slots 6 and the projections of the auxiliary teeth and slots 7 are staggered, or, along the axial direction of the rotor shaft 1, the projections of the main permanent magnets 2 and the projections of the auxiliary permanent magnets 3 are staggered.

[0035] In some embodiments, in order to make the waveforms of the main cogging torque and the auxiliary cogging torque always correspond within the full rotation period of the rotor shaft 1, the number of the main teeth and slots 6 is the same as the number of the auxiliary teeth and slots 7, and / or, the number of the main permanent magnets 2 is the same as the number of the auxiliary permanent magnets 3, so that the fluctuation periods of the main cogging torque and the auxiliary cogging torque are the same.

[0036] In some embodiments, the main teeth and slots 6 are uniformly arranged circumferentially on the inner wall of the shaft hole of the main stator core 4, and / or, the auxiliary teeth and slots 7 are uniformly arranged axially on the inner wall of the shaft hole of the auxiliary stator core 5, which can also make the fluctuation periods of the main cogging torque and the auxiliary cogging torque the same.

[0037] In some embodiments, in order to improve the magnetic field performance of the main permanent magnets 2, a main rotor core 8 is provided on the rotor shaft 1, and the main permanent magnets 2 are arranged on the main rotor core 8, and / or, in order to improve the magnetic field performance of the auxiliary permanent magnets 3, an auxiliary rotor core is provided on the rotor shaft 1, and the auxiliary permanent magnets 3 are arranged on the auxiliary rotor core. The auxiliary permanent magnets 3 can be pasted on the surface of the auxiliary rotor core or embedded inside the auxiliary rotor core.

[0038] In some embodiments, the motor includes a brake 9, and the auxiliary stator core 5 is a brake core. The function of the brake 9 is to lock the rotor shaft 1 to maintain its position when the motor is powered off. When the brake 9 is powered on, the rotor shaft 1 can rotate. When the brake 9 loses power, the brake 9 locks the rotor shaft 1, and the rotor shaft 1 cannot rotate. As a common structure inside the motor, the brake 9 usually has an iron core sleeved on the rotor shaft 1. Using the brake iron core as the auxiliary stator core 5 and arranging the auxiliary permanent magnets 3 on the corresponding rotor shaft 1 of the brake iron core, making full use of the existing motor structure to achieve the function of reducing the cogging torque, can improve the structural compactness of the motor and improve the performance of the motor.

[0039] In some embodiments, when auxiliary teeth grooves 7 are provided on the inner wall of the shaft hole of the auxiliary iron core, the auxiliary teeth grooves 7 are provided on the inner wall of the shaft hole of the brake iron core. In this embodiment, the auxiliary teeth grooves 7 are formed on the brake iron core, which can achieve the function of reducing the cogging torque, and is beneficial to improving the structural compactness of the motor and enhancing the performance of the motor.

[0040] In some embodiments, the auxiliary permanent magnet 3 can also be a magnetic ring, and the number of poles of the magnetic ring is the same as that of the main permanent magnet 2. The magnetic ring can generate the same function of reducing the cogging torque of the motor as the auxiliary permanent magnet 3, and the magnetic ring has the advantages of simplicity and convenient installation.

[0041] In some embodiments, the main teeth groove 6 is a skewed groove, and / or the main permanent magnet 2 is a skewed pole, and / or the auxiliary teeth groove 7 is a skewed groove, and / or the auxiliary permanent magnet 3 is a skewed pole. The skewed groove or skewed pole design itself can weaken the cogging torque of the motor. On the basis of the reduction of the main teeth groove torque by the auxiliary permanent magnet 3 and the auxiliary stator iron core 5 in this embodiment, the adoption of the skewed groove or skewed pole design can further reduce the main teeth groove torque and improve the performance of the motor.

[0042] In some embodiments, the main permanent magnet 2 and the auxiliary permanent magnet 3 are permanent magnetic materials with high magnetic energy product, such as neodymium iron boron, samarium cobalt, etc., and the auxiliary stator iron core 5 and the stator iron core of the brake 9 are metal materials with high magnetic conductivity, such as low-carbon steel, etc.

[0043] In the motor of this embodiment, by making the auxiliary teeth groove 7 deviate from the main teeth groove 6 by an angle, and the two magnet positions on the rotor shaft 1 are installed without deviation angle, or the auxiliary teeth groove 7 and the main teeth groove 6 have no angular deviation, while the installation of the two magnets on the rotor shaft 1 has a deviation angle, so that the cogging torques generated at the two places when the motor rotor rotates can cancel each other out, thereby achieving the purpose of reducing the cogging torque of the motor.

[0044] It is easy for those skilled in the art to understand that on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0045] The above are only the preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure. The above is only the preferred implementation manner of the present disclosure. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present disclosure, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present disclosure.

Claims

1. A motor, characterized in that, comprising: a rotor shaft (1), on which a main permanent magnet (2) and an auxiliary permanent magnet (3) are provided, and the main permanent magnet (2) and the auxiliary permanent magnet (3) are arranged at intervals along the axial direction of the rotor shaft (1); a main stator core (4) and an auxiliary stator core (5), the main stator core (4) and the auxiliary stator core (5) are arranged at intervals axially on the rotor shaft (1), the main stator core (4) corresponds to the position of the main permanent magnet (2), and the auxiliary stator core (5) corresponds to the position of the auxiliary permanent magnet (3); the main permanent magnet (2) and the main stator core (4) interact to generate a main cogging torque, the auxiliary stator core (5) and the auxiliary permanent magnet (3) interact to generate an auxiliary cogging torque, and the main cogging torque and the auxiliary cogging torque can cancel each other out; main tooth grooves (6) are provided on the inner wall of the shaft hole of the main stator core (4), and auxiliary tooth grooves (7) are provided on the inner wall of the shaft hole of the auxiliary stator core (5); along the axial direction of the rotor shaft (1), the projection of the main tooth groove (6) intersects with the projection of the auxiliary tooth groove (7), or, along the axial direction of the rotor shaft (1), the projection of the main permanent magnet (2) intersects with the projection of the auxiliary permanent magnet (3); a main rotor core (8) is provided on the rotor shaft (1), and the main permanent magnet (2) is arranged on the main rotor core (8).

2. The motor according to claim 1, characterized in that, the number of the main tooth grooves (6) is the same as the number of the auxiliary tooth grooves (7), and / or, the number of the main permanent magnets (2) is the same as the number of the auxiliary permanent magnets (3).

3. The motor according to claim 1, characterized in that, the main tooth grooves (6) are uniformly arranged circumferentially along the inner wall of the shaft hole of the main stator core (4), and / or, the auxiliary tooth grooves (7) are uniformly arranged axially along the inner wall of the shaft hole of the auxiliary stator core (5).

4. The motor according to claim 1, characterized in that, an auxiliary rotor core is provided on the rotor shaft (1), and the auxiliary permanent magnet (3) is arranged on the auxiliary rotor core.

5. The motor according to any one of claims 1-4, characterized in that, the motor includes a brake (9), and the auxiliary stator core (5) is a brake core.

6. The motor according to claim 5, characterized in that, when the auxiliary tooth grooves (7) are provided on the inner wall of the shaft hole of the auxiliary stator core (5), the auxiliary tooth grooves (7) are provided on the inner wall of the shaft hole of the brake core.

7. The motor according to claim 1, characterized in that, the auxiliary permanent magnet (3) can also be a magnetic ring, and the number of poles of the magnetic ring is the same as the number of poles of the main permanent magnet (2).

8. The motor according to claim 1, characterized in that, the main tooth grooves (6) are skewed slots, and / or, the main permanent magnets (2) are skewed poles, and / or, the auxiliary tooth grooves (7) are skewed slots, and / or, the auxiliary permanent magnets (3) are skewed poles.

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