Rotor assembly, motor and compressor
By adjusting the arrangement angle of the magnets in the rotor assembly and alternately setting the first and second magnets, the problem of limited rare earth resources in rare earth permanent magnet motors is solved, and the amount of rare earth permanent magnets used is reduced while maintaining high performance, thereby improving magnet utilization and motor efficiency.
Patent Information
- Application Number
- CN202410980179.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2026-01-20
AI Technical Summary
How to reduce the amount of rare earth permanent magnets used while ensuring the high performance of permanent magnet motors, in order to cope with the limited availability of rare earth resources.
By alternately setting the first magnet and the second magnet in the rotor assembly and adjusting the arrangement angle of the magnets, the width direction of the first magnet forms a certain angle with the radial direction of the rotor core, and the width direction of the second magnet forms a certain angle with the tangential direction of the rotor core, thereby increasing the utilization rate of the magnets and reducing the amount of rare earth permanent magnets used.
Without reducing the magnetic flux, the utilization rate of the magnet is improved, the amount of rare earth permanent magnets is reduced, and the high performance of the permanent magnet motor is maintained. The magnetic flux path is optimized, and the efficiency and stability of the motor are improved.
Smart Images
Figure CN121367342A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electric machines, in particular to a rotor assembly, an electric machine and a compressor. BACKGROUND
[0002] At present, permanent magnet machines have the advantages of simple structure, high reliability, high efficiency and high power density, and are widely used. Among them, due to the high magnetic energy product of rare earth permanent magnet, the performance of rare earth permanent magnet machine is very excellent. However, the reserves of rare earth resources are very limited, and the home appliance manufacturing industry should actively respond to the call of the state to reduce the dependence on rare earth permanent magnet. Completely using non-rare earth permanent magnet to replace rare earth permanent magnet will lead to serious deterioration of the performance of the electric machine, so mixed use of rare earth permanent magnet and non-rare earth permanent magnet becomes an important research direction, which can greatly reduce the use of rare earth permanent magnet while ensuring the high performance of the permanent magnet machine. Among them, how to further expand the reduction of rare earth permanent magnet through the optimization design of the structure of the electric machine has become a current research hotspot. SUMMARY
[0003] The main purpose of the present application is to provide a rotor assembly, an electric machine and a compressor, which can reduce the use of rare earth permanent magnet while ensuring the high performance of the permanent magnet machine.
[0004] To achieve the above-mentioned purpose, the rotor assembly provided by the present application comprises:
[0005] a rotor core; and
[0006] a plurality of first magnets and a plurality of second magnets, which are alternately and spacedly arranged in the rotor core along the circumferential direction of the rotor core, both ends of each of the first magnets and the second magnets in the length direction are arranged along the axial direction of the rotor core, both sides of each of the first magnets in the width direction are arranged along the radial direction of the rotor core, and both ends of each of the second magnets in the width direction are arranged along the circumferential direction of the rotor core;
[0007] wherein the first included angle between the line connecting the center of the first magnet and the center of the rotor core and the width direction of the first magnet is α, the second included angle between the line connecting the center of the second magnet and the center of the rotor core and the width direction of the second magnet is β, and at least one of α and |β-90°| is greater than 0°.
[0008] In an embodiment, at least one of α and |β-90°| is greater than or equal to 5°.
[0009] In an embodiment, α≤60° and / or |β-90°|≤30°.
[0010] In an embodiment, the first plurality of magnets are arranged symmetrically about a center of the rotor core; and / or,
[0011] the second plurality of magnets are arranged symmetrically about the center of the rotor core.
[0012] In an embodiment, the first plurality of magnets have a maximum energy product greater than a maximum energy product of the second plurality of magnets.
[0013] In an embodiment, the first plurality of magnets are made of rare earth permanent magnet; and / or,
[0014] the second plurality of magnets are made of ferrite.
[0015] In an embodiment, the first plurality of magnets have a magnetization direction coinciding with a thickness direction of the first plurality of magnets; and / or,
[0016] the second plurality of magnets have a magnetization direction coinciding with a thickness direction of the second plurality of magnets.
[0017] In an embodiment, two of the first plurality of magnets arranged adjacently have a same magnetic polarity at an opposite end.
[0018] In an embodiment, the second plurality of magnets have a same magnetic polarity at an end close to an outer side of the rotor core as two of the first plurality of magnets arranged adjacently have at an opposite end.
[0019] The present application also provides an electric machine, comprising a rotor assembly, the rotor assembly comprising:
[0020] a rotor core; and,
[0021] a first plurality of magnets and a second plurality of magnets alternately and spacedly arranged in the rotor core along a circumferential direction of the rotor core, two ends of each of the first plurality of magnets and the second plurality of magnets along an axial direction of the rotor core are arranged, two side ends of each of the first plurality of magnets along a radial direction of the rotor core are arranged, and two ends of each of the second plurality of magnets along the circumferential direction of the rotor core are arranged;
[0022] wherein a first included angle between a line connecting a center of the first plurality of magnets and a center of the rotor core and a width direction of the first plurality of magnets has an angle of a, and a second included angle between a line connecting a center of the second plurality of magnets and the center of the rotor core and a width direction of the second plurality of magnets has an angle of β, at least one of a and |β-90°| is greater than 0°.
[0023] The present application also provides a compressor, comprising a rotor assembly, the rotor assembly comprising:
[0024] a rotor core; and
[0025] a plurality of first magnets and a plurality of second magnets, which are alternately and spacedly arranged in the rotor core along a circumferential direction of the rotor core, two ends of each of the first magnets and the second magnets in a length direction of the first magnets and the second magnets are arranged along an axial direction of the rotor core, two side ends of each of the first magnets in a width direction of the first magnets are arranged along a radial direction of the rotor core, and two ends of each of the second magnets in the width direction of the second magnets are arranged along the circumferential direction of the rotor core;
[0026] wherein an angle of a first included angle between a line connecting a center of the first magnet and a center of the rotor core and the width direction of the first magnet is α, an angle of a second included angle between a line connecting a center of the second magnet and the center of the rotor core and the width direction of the second magnet is β, and at least one of α and |β-90°| is greater than 0°.
[0027] In the technical scheme, when the angle α of the first included angle between the line connecting the center of the first magnet and the center of the rotor core and the width direction of the first magnet is greater than 0°, the width direction of the first magnet is not extended along the radial direction of the rotor core, but forms a certain included angle with the radial direction of the rotor core, so that the first magnet can be arranged to be wider, thereby improving the utilization rate of the first magnet and increasing the magnetic flux of the rotor assembly; when the angle |β-90°| of the second included angle between the line connecting the center of the second magnet and the center of the rotor core and the width direction of the second magnet is greater than 0°, the width direction of the second magnet is not extended along the tangent direction of the rotor core, so that the second magnet arranged between two adjacent first magnets can be arranged to be wider, thereby improving the utilization rate of the second magnet and also increasing the magnetic flux of the rotor assembly, that is, under the condition of the same magnetic flux, the amount of rare earth permanent magnet can be reduced, so as to provide a motor which can ensure the high performance of the permanent magnet motor and reduce the amount of rare earth permanent magnet. BRIEF DESCRIPTION OF DRAWINGS
[0028] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0029] Figure 1 Structure diagram of an embodiment of the rotor assembly provided by the present application;
[0030] Figure 2 Structure diagram of another embodiment of the rotor assembly provided by the application;
[0031] Figure 3 For Figure 1 Schematic diagram of the inclination angle of the first magnet and the second magnet.
[0032] Explanation of reference numerals:
[0033] 100, rotor assembly; 1, rotor core; 2, first magnet; 3, second magnet.
[0034] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION
[0035] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.
[0036] It should be noted that if the embodiments of the application involve directionality indications (such as up, down, left, right, front, back, etc.), the directionality indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directionality indications also change accordingly.
[0037] In addition, if the embodiments of the application involve descriptions such as “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first” and “second” can explicitly or implicitly include at least one of the features. In addition, “and / or” or “and / or” appearing throughout the text means that the three parallel schemes are included, for example, “α and / or β” includes the α scheme, or the β scheme, or the α and β schemes are satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the application.
[0038] At present, permanent magnet motor has the advantages of simple structure, high reliability, high efficiency and high power density, and is widely used. Among them, due to the high energy product of rare earth permanent magnet, the performance of rare earth permanent magnet motor is very excellent. However, the reserves of rare earth resources are very limited, and the household appliance manufacturing industry should actively respond to the call of the state and reduce the dependence on rare earth permanent magnet. Completely using non-rare earth permanent magnet to replace rare earth permanent magnet will cause the performance of the motor to deteriorate seriously, so the mixed use of rare earth permanent magnet and non-rare earth permanent magnet becomes an important research direction, which can greatly reduce the use of rare earth permanent magnet while ensuring the high performance of the permanent magnet motor. Among them, how to further expand the reduction of rare earth permanent magnet through motor structure optimization design has become a current research hotspot.
[0039] The application provides a rotor assembly, aiming to reduce the use of rare earth permanent magnet while ensuring the high performance of a permanent magnet motor.
[0040] Please refer to Figures 1 to 3 In an embodiment of the application, the rotor assembly 100 comprises a rotor core 1, a plurality of first magnets 2 and a plurality of second magnets 3, the plurality of first magnets 2 and the plurality of second magnets 3 are alternately and spacedly arranged in the rotor core 1 along the circumferential direction of the rotor core 1, the two ends of each first magnet 2 and each second magnet 3 in the length direction of the first magnet 2 and the second magnet 3 are arranged along the axial direction of the rotor core 1, the two side ends of each first magnet 2 in the width direction of the first magnet 2 are arranged along the radial direction of the rotor core 1, and the two ends of each second magnet 3 in the width direction of the second magnet 3 are arranged along the circumferential direction of the rotor core 1; wherein the first included angle between the line connecting the center of the first magnet 2 and the center of the rotor core 1 and the width direction of the first magnet 2 is α, the second included angle between the line connecting the center of the second magnet 3 and the center of the rotor core 1 and the width direction of the second magnet 3 is β, and at least one of α and |β-90°| is greater than 0°.
[0041] It should be noted that the rotor core 1 has a plurality of mounting grooves for mounting the plurality of first magnets 2 and the plurality of second magnets 3, each mounting groove extends along the axial direction of the rotor core 1, the plurality of mounting grooves comprise a plurality of first mounting grooves and a plurality of second mounting grooves, the plurality of first mounting grooves are used for corresponding mounting of the plurality of first magnets 2, and the plurality of second mounting grooves are used for corresponding mounting of the plurality of second magnets 3.
[0042] The first magnet 2 is arranged in the length direction of the first magnet 2 in the thickness direction of the rotor core 1, the first magnet 2 is arranged in the width direction of the first magnet 2 in the radial direction of the rotor core 1, and the first magnet 2 is arranged in the thickness direction of the first magnet 2 in the circumferential direction of the rotor core 1.
[0043] The second magnet 3 is arranged in the length direction of the second magnet 3 in the thickness direction of the rotor core 1, is arranged in the thickness direction of the second magnet 3 in the radial direction of the rotor core 1, and is arranged in the width direction of the second magnet 3 in the circumferential direction of the rotor core 1.
[0044] The line connecting the center of the first magnet 2 and the center of the rotor core 1 is a line connecting the geometric center of the first magnet 2 and the geometric center of the rotor core 1 in the cross section of the rotor core 1. It can be understood that if there is an included angle α between the width direction of the first magnet 2 and the line and the included angle α is greater than 0°, it means that the width direction of the first magnet 2 is not coincident with the radial direction of the rotor core 1, and the first magnet 2 is inclined.
[0045] Similarly, the line connecting the center of the second magnet 3 and the center of the rotor core 1 is a line connecting the geometric center of the second magnet 3 and the geometric center of the rotor core 1 in the cross section of the rotor core 1. It can be understood that if there is an included angle |β-90°| between the width direction of the second magnet 3 and the line and the included angle |β-90°| is equal to 0°, it means that the direction of the width of the second magnet 3 is coincident with the tangent direction of the center of the second magnet 3, and if the included angle |β-90°| is greater than 0°, it means that the extension direction of the width of the second magnet 3 is not along the tangent direction, and the second magnet 3 is inclined.
[0046] It can be understood that the inclination direction of the first magnet 2 and the second magnet 3 can be clockwise rotation on the basis of the original, or counterclockwise rotation on the basis of the original.
[0047] It can be understood that when the rotor assembly 100 is applied to a permanent magnet synchronous motor, the first magnet 2 and the second magnet 3 are arranged as permanent magnets to provide a constant magnetic field, which interacts with the rotating magnetic field generated by the stator winding to generate torque.
[0048] In the technical solution of the present application, when the first included angle between the line connecting the center of the first magnet 2 and the center of the rotor core 1 and the width direction of the first magnet 2 is greater than 0°, the width direction of the first magnet 2 is not along the radial direction of the rotor core 1, but at a certain angle with the radial direction of the rotor core 1, then the first magnet 2 can be set wider, thereby improving the utilization rate of the first magnet 2 and increasing the magnetic flux of the rotor assembly 100; when the second included angle between the line connecting the center of the second magnet 3 and the center of the rotor core 1 and the width direction of the second magnet 3 is greater than 0°, the width direction of the second magnet 3 is not along the tangent direction of the rotor core 1, then the second magnet 3 arranged between two adjacent first magnets 2 can be set wider, thereby improving the utilization rate of the second magnet 3 and also increasing the magnetic flux of the rotor assembly 100, that is, under the condition of constant magnetic flux, the amount of rare earth permanent magnet can be reduced, thereby providing a motor that can guarantee the high performance of the permanent magnet motor without changing the amount of rare earth permanent magnet.
[0049] Further, in theory, as long as the relative inclination occurs, the width of the first magnet 2 and / or the second magnet 3 can be set wider, and the utilization rate of the magnet can be improved. In order to make the above-mentioned effect more obvious, in the present embodiment, at least one of α and |β-90°| is greater than or equal to 5°. In this way, the rotor assembly 100 can fully realize the technical effect of increasing the magnetic flux.
[0050] In the present embodiment, α≤60° and / or |β-90°|≤30°.
[0051] It should be noted that in a permanent magnet motor, the arrangement of the magnets has a direct impact on the magnetic circuit of the motor, and further affects the performance of the motor. The magnetic circuit can be compared to the circuit path in an electrical circuit, where the magnetic flux flows in the magnetic circuit like an electric current. Ideally, the magnetic flux should flow as efficiently as possible from one magnetic pole to another, forming a closed path. When the first included angle and the second included angle are set within the above range, they can help optimize the magnetic flux path and ensure that the magnetic flux can flow between the stator and the rotor in the most efficient way. This improves the utilization rate of the magnets, as the magnetic flux is more concentrated and directional, thereby producing stronger electromagnetic torque and higher motor efficiency.
[0052] If the first and second included angles are set too large, beyond the range described above, the magnetic flux can no longer be completely closed in the predetermined magnetic circuit, but partially leaks into the air or other non-magnetic material. This reduces the effective magnetic flux, reduces the utilization rate of the magnet, and can cause some parts of the magnetic circuit to be too concentrated, causing local magnetic saturation, which means that the magnetic flux density of those parts reaches the maximum value of the material and cannot be increased, while the magnetic flux of other parts is insufficient, which also reduces the overall magnetic flux efficiency, thus affecting the magnetic circuit of the rotor assembly 100 and ultimately degrading the performance of the motor.
[0053] Specifically, in the present embodiment, the plurality of first magnets 2 are arranged in central symmetry about the center of the rotor core 1; and / or, the plurality of second magnets 3 are arranged in central symmetry about the center of the rotor core 1.
[0054] In this way, the central-symmetrical magnet arrangement helps to form a uniform magnetic field, reducing the magnetic force imbalance inside the motor and avoiding vibration and noise during motor operation. In a permanent magnet synchronous motor, torque is generated by the interaction of the stator current and the magnetic field generated by the permanent magnets. A symmetrical magnet arrangement ensures that this interaction is balanced regardless of the position of the rotor, thus providing smooth torque. Therefore, arranging the plurality of first magnets 2 in central symmetry about the center of the rotor core 1; and / or, arranging the plurality of second magnets 3 in central symmetry about the center of the rotor core 1 not only improves the dynamic response and stability of the motor, but also simplifies the control logic and reduces maintenance and operating costs.
[0055] In the present embodiment, the maximum magnetic energy product of the first magnet 2 is set to be greater than the maximum magnetic energy product of the second magnet 3.
[0056] It should be noted that the maximum magnetic energy product (BHmax) is an indicator of the amount of magnetic energy a magnet can store at a specific operating point, which reflects the performance level of the magnet. The larger the maximum magnetic energy product, the stronger the magnetic performance of the magnet at the same volume.
[0057] It should also be noted that during motor operation, the outer magnets closest to the stator windings are most affected by the armature reaction field. Placing the first magnets 2 with higher magnetic energy on the outer side ensures that the demagnetization resistance meets the requirements and improves the reliability of the magnets.
[0058] In related technologies, high-performance first magnets 2 are used on the outer side, while lower-cost second magnets 3 are used on the inner side, which can balance performance and cost and reduce the overall manufacturing cost of the motor.
[0059] In the embodiment, the first magnet 2 is made of rare earth permanent magnet; and / or, the second magnet 3 is made of ferrite.
[0060] The first magnet is made of rare earth permanent magnet, and the maximum magnetic energy product thereof is generally greater than 200kJ / m 3 ; the second magnet is made of ferrite, and the maximum magnetic energy product thereof is generally less than 100kJ / m 3 .
[0061] It is to be noted that the rare earth permanent magnet is generally made of neodymium iron boron (NdFeB) and samarium cobalt (SmCo), and can also be other permanent magnet materials containing rare earth elements.
[0062] In the embodiment, the magnetization direction of the first magnet 2 is consistent with the thickness direction of the first magnet 2; and / or, the magnetization direction of the second magnet 3 is consistent with the thickness direction of the second magnet 3.
[0063] In this way, the magnetization direction of the magnet is consistent with the thickness direction of the magnet, and the first magnet 2 and the second magnet 3 can generate the maximum magnetic flux density between the main planes (i.e., the two larger faces) thereof, so as to ensure that the magnet can exert the maximum magnetic performance in use, which is helpful to optimize the magnetic circuit, ensure that the magnetic flux propagates in the expected direction, reduce the magnetic flux leakage, and improve the system efficiency, so as to avoid the decrease of the magnetic performance and the increase of the magnetic flux leakage.
[0064] Further, in the embodiment, the magnetic poles of the two first magnets 2 arranged adjacently and located at the opposite ends are arranged in the same polarity. In this way, the magnetic flux of the two first magnets 2 arranged adjacently can be superimposed on each other, instead of being reduced by each other.
[0065] Further, in the embodiment, the magnetic pole of the second magnet 3 located at one end close to the outer side of the rotor core 1 is arranged in the same polarity as the magnetic pole of the first magnet 2 arranged adjacently and located at the opposite end. The second magnet 3 further superimposes the magnetic flux between the two first magnets 2, so as to form a magnetic pole region with larger magnetic flux outside the rotor core 1.
[0066] The application further provides an electric machine, which comprises a stator assembly and a rotor assembly 100. The specific structure of the rotor assembly 100 is as described above. Since the electric machine adopts all the technical solutions of the above embodiments, it has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described herein again.
[0067] The application further provides a compressor, which comprises a motor, the specific structure of which is referred to the above-mentioned embodiments, and the compressor adopts all the technical solutions of the above-mentioned embodiments, so that it has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.
[0068] The above merely describes exemplary embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like, which is made under the technical concept of the present application, and based on the content of the present application specification and drawings, is included in the patent protection scope of the present application.
Claims
1. A rotor assembly characterized by, The rotor assembly comprises: a rotor core; a plurality of first magnets and a plurality of second magnets, which are alternately and spacedly arranged in the rotor core along a circumferential direction of the rotor core, two ends of each of the first magnets and the second magnets along a length direction of the first magnets and the second magnets are arranged along an axial direction of the rotor core, two side ends of each of the first magnets along a width direction of the first magnets are arranged along a radial direction of the rotor core, and two ends of each of the second magnets along the width direction of the second magnets are arranged along the circumferential direction of the rotor core; wherein a first included angle between a line connecting a center of the first magnet and a center of the rotor core and a width direction of the first magnet is α, a second included angle between a line connecting a center of the second magnet and the center of the rotor core and the width direction of the second magnet is β, and at least one of α and |β-90°| is greater than 0°. At least one of α and |β-90°| is greater than or equal to 5°.
2. The rotor assembly of claim 1, wherein α≤60° and / or |β-90°|≤30°.
3. The rotor assembly of claim 2, wherein The plurality of first magnets are arranged in a central symmetry about the center of the rotor core; and / or 4. The rotor assembly of claim 1, wherein The plurality of second magnets are arranged in a central symmetry about the center of the rotor core. A maximum magnetic energy product of the first magnet is greater than a maximum magnetic energy product of the second magnet.
5. The rotor assembly of any one of claims 1 to 4, wherein, The first magnet is made of a rare earth permanent magnet; and / or 6. The rotor assembly of claim 5, wherein The second magnet is made of a ferrite. A magnetization direction of the first magnet is consistent with a thickness direction of the first magnet; and / or 7. The rotor assembly of claim 1, wherein A magnetization direction of the second magnet is consistent with a thickness direction of the second magnet. Two first magnets arranged adjacently are arranged with the same magnetic pole polarity at one end thereof.
8. The rotor assembly of claim 7, wherein A magnetic pole polarity of one end of the second magnet close to an outer side of the rotor core is the same as a magnetic pole polarity of one end of two first magnets arranged adjacently.
9. The rotor assembly of claim 8, wherein The rotor assembly comprises any one of claims 1 to 9.
10. An electric machine characterized by The motor comprises claim 10.
11. A compressor characterized by,