Rotor assembly, permanent magnet motor and compressor

Abstract

The application provides a rotor assembly, a permanent magnet motor and a compressor, and the rotor assembly comprises: a rotor core comprising a through hole; a permanent magnet arranged in the through hole, the permanent magnet is cut by a plane perpendicular to an axis of the rotor core to obtain a first cross section, and an included angle between an extension direction of the permanent magnet and a radial direction of the rotor core on the first cross section is greater than 0° and less than 90°, and the permanent magnet comprises: a non-diffusion part, in the extension direction, the non-diffusion part comprises a first end and a second end, the first end is adjacent to a circumferential side surface of the rotor core, and the second end is adjacent to the axis of the rotor core; a first diffusion part, which is connected with the first end of the non-diffusion part; a first magnetic isolation bridge, which is connected with the first diffusion part and is located between the first diffusion part and the circumferential side surface of the rotor core; and wherein a mass proportion of heavy metal elements in the first diffusion part is greater than that in the non-diffusion part. The application solves the technical problems of weak anti-demagnetization ability and easy irreversible demagnetization of the permanent magnet motor.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, and more specifically, to a rotor assembly, a permanent magnet motor, and a compressor. Background Technology

[0002] Currently, most air conditioner compressors both domestically and internationally use variable frequency motors (VFM motors), which generally employ permanent magnet motors. The rotor of a permanent magnet motor is excited by permanent magnets. Due to the high power density of modern permanent magnet motors and the need for cost reduction, the demagnetization resistance of the rotor's permanent magnets has weakened. When irreversible demagnetization occurs, it affects the operating performance and reliability of the motor and compressor, severely impacting the product's lifespan.

[0003] Therefore, how to design a rotor assembly that can effectively solve the above-mentioned technical defects has become an urgent technical problem to be solved. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] Therefore, the first aspect of the present invention provides a rotor assembly.

[0006] The second aspect of this invention proposes a permanent magnet motor.

[0007] A third aspect of the present invention provides a compressor.

[0008] In view of the above, the first aspect of this application proposes a rotor assembly, the rotor assembly comprising: a rotor core including a through hole; a permanent magnet disposed in the through hole, the permanent magnet being cut through a plane perpendicular to the axis of the rotor core to obtain a first cross section, wherein on the first cross section, the angle between the extension direction of the permanent magnet and the radial direction of the rotor core is greater than 0° and less than 90°, the permanent magnet comprising: a non-diffusion portion, which includes a first end and a second end in the extension direction, the first end being adjacent to the peripheral surface of the rotor core, and the second end being adjacent to the axis of the rotor core; a first diffusion portion connected to the first end of the non-diffusion portion; and a first magnetic isolation bridge connected to the first diffusion portion and located between the first diffusion portion and the peripheral surface of the rotor core; wherein the mass percentage of heavy metal elements in the first diffusion portion is greater than the mass percentage of heavy metal elements in the non-diffusion portion.

[0009] This application defines a rotor assembly for use in a permanent magnet motor. Specifically, the rotor assembly includes a rotor core and permanent magnets. The rotor core is formed by stacking multiple rotor laminations, each lamination having an opening at a corresponding position. Aligning and stacking the openings of the multiple rotor laminations together forms an axially penetrating through-hole in the rotor core. The permanent magnets are inserted into the through-holes, the shape of which matches the outer contour of the permanent magnets, whereby the permanent magnets provide excitation.

[0010] In related technologies, various products demand high power density and low cost from permanent magnet motors. This requirement limits the design of permanent magnet motors, leading to technical problems such as weak demagnetization resistance and susceptibility to irreversible demagnetization. Irreversible demagnetization can cause the permanent magnet motor and related products to fail, directly impacting product lifespan and negatively affecting the user experience.

[0011] In this application, the technical solution divides the permanent magnet into a non-diffusion portion and a diffusion portion by adjusting the heavy metal element content in a local area. Specifically, the diffusion portion and at least a portion of the non-diffusion portion are arranged side-by-side on the permanent magnet in a first direction. This first direction is perpendicular to the axial direction of the rotor core; that is, by cutting the permanent magnet with a plane perpendicular to the rotor core, the side-by-side diffusion and non-diffusion portions can be simultaneously obtained on the cut surface.

[0012] The first cross-section is obtained by cutting the permanent magnet with a plane perpendicular to the axis of the stator core. On this first cross-section, the extension direction of the permanent magnet is inclined to the radial direction of the rotor core, with an inclination angle less than 90°. In the extension direction of the permanent magnet, the non-diffusion portion includes a first end and a second end. The first end is close to the circumferential surface of the stator core, and the second end is close to the centerline of the stator core. The diffusion portion includes a first diffusion portion, which is connected to the first end of the non-diffusion portion. In the non-diffusion portion, the ratio of the mass of heavy metal elements to the total mass of the diffusion portion is called the mass percentage of metal elements in the diffusion portion, g1. Correspondingly, in the first diffusion portion, the ratio of the mass of heavy metal elements to the total mass of the non-diffusion portion is called the mass percentage of metal elements in the non-diffusion portion, g2, where g2 is greater than g1.

[0013] By ensuring that the mass percentage of heavy metal elements in the first diffusion section is greater than that in the non-diffusion section, it is possible to ensure that the coercivity of the first diffusion section, which is arranged side-by-side in the first direction, is greater than that of the non-diffusion section. This creates a diffusion zone with strong demagnetization resistance in certain areas of the permanent magnet, thereby improving the local demagnetization resistance of the permanent magnet and ultimately enhancing the overall demagnetization resistance of the rotor assembly. This reduces the possibility of irreversible demagnetization in the rotor assembly, ensuring reliable operation of the permanent magnet motor and related products over extended periods and extending their service life.

[0014] Therefore, the rotor assembly defined in this application solves the technical problems existing in related technologies, such as the weak demagnetization resistance and susceptibility to irreversible demagnetization in permanent magnet motors. Simultaneously, this structure can improve the demagnetization resistance of the rotor assembly without increasing the volume of the permanent magnet, thus balancing the high power density and low cost requirements of permanent magnet motors. This results in optimized rotor assembly structure, improved rotor assembly reliability, extended rotor assembly lifespan, and reduced product failure rate.

[0015] Building upon this, the rotor assembly also incorporates a first magnetic isolation bridge, which is connected to the first diffusion section and located between the circumferential surface of the rotor core and the first diffusion section. The first magnetic isolation bridge provides a degree of magnetic isolation, effectively reducing the likelihood of internal magnetic circuit disorder and magnetic leakage within the rotor assembly. This achieves the technical effect of optimizing the rotor assembly structure and improving its practicality and reliability.

[0016] In addition, the rotor assembly provided by the present invention may also have the following additional technical features:

[0017] In the above technical solution, the distance between the first magnetic isolation bridge and the peripheral side of the rotor core in the radial direction is W1; the length of the first diffusion portion in the extending direction is L1, where W1 1.3 ×L1=K1, 0.04≤K1≤0.57, where K1 is the first dimension ratio.

[0018] In this technical solution, the dimensional relationship between the first magnetic isolation bridge and the first diffusion section is defined. Specifically, the distance between the first magnetic isolation bridge and the circumferential surface of the rotor core is W1, that is, the minimum distance between the first magnetic isolation bridge and the circumferential surface of the rotor core in the radial direction is W1. On the first cross-section, the length of the first diffusion section in the direction of permanent magnet extension is L1. Based on this, W1 and L1 satisfy the following relationship, W1 1.3 ×L1=K1, 0.04≤K1≤0.57. By limiting the above dimensional relationships, the local anti-demagnetization ability of the magnet can be improved while ensuring demagnetization reliability and without increasing the magnet volume. This, in turn, improves the anti-demagnetization ability of the rotor assembly and reduces the cost of the rotor assembly.

[0019] In any of the above technical solutions, the mass percentage of heavy metal elements in the first diffusion section is greater than or equal to 0.6 and less than or equal to 0.8.

[0020] In this technical solution, the mass percentage of heavy metal elements in the first diffusion section is limited. Specifically, the mass percentage of heavy metal elements in the first diffusion section must be greater than or equal to 0.6 and less than or equal to 0.8. By limiting the mass percentage of heavy metal elements in the first diffusion section to greater than 0.6, it can be ensured that the first diffusion section has greater coercivity than the non-diffusion section, thereby ensuring that the first diffusion section can improve the demagnetization resistance of the entire permanent magnet. By limiting the mass percentage of heavy metal elements in the first diffusion section to less than 0.8, the production cost of the permanent magnet can be reduced while ensuring that the first diffusion section has strong demagnetization resistance, thereby meeting the low-cost requirements of permanent magnet motors and enhancing the market competitiveness of the product.

[0021] In any of the above technical solutions, two permanent magnets form a group, and the rotor assembly includes multiple groups of permanent magnets; on the first cross section, the two permanent magnets in the same group are distributed in a V-shape.

[0022] In this technical solution, the layout of permanent magnets on the rotor assembly is defined. Specifically, each rotor assembly is provided with multiple sets of permanent magnets, which are arranged around the axis of the rotor core. Each set of permanent magnets includes two permanent magnets, which are symmetrically arranged on both sides of a first plane. The axis and diameter of the rotor core are both within the first plane. Specifically, the first plane is defined by cutting a section of the rotor core and permanent magnets perpendicular to the axis of the rotor core.

[0023] By incorporating multiple sets of permanent magnets on the rotor assembly, its resistance to demagnetization can be enhanced, thereby further reducing the possibility of irreversible demagnetization. Furthermore, by symmetrically distributing two permanent magnets from each set on both sides of the first plane, multiple regions with strong demagnetization resistance can be formed around the rotor core shaft, thus improving the overall demagnetization resistance of the rotor core. This ultimately enhances the reliability of the rotor assembly and extends its service life.

[0024] In each group of permanent magnets, two permanent magnets are arranged in a V-shape on both sides of the first plane. Specifically, the permanent magnets are cut through a plane perpendicular to the axis of the rotor core. On this cross-section, the two permanent magnets in the same group have an angle with the first plane, the angle of which is less than 90°, to form two permanent magnets arranged in a V-shape. The opening of the two permanent magnets in the V-shape can face the axis of the rotor core or the outside of the rotor core; this technical solution does not impose a strict limitation on this.

[0025] By distributing two permanent magnets in the same group in a V-shape, a hybrid magnetic circuit structure can be formed in the rotor assembly. This hybrid magnetic circuit structure improves the steady-state and dynamic performance of the rotor assembly, helps increase the power density and overload capacity of the permanent magnet motor, and facilitates field weakening for speed extension. Furthermore, it increases the coverage area of ​​the permanent magnets in the circumferential direction of the rotor core, thereby enhancing the performance of the permanent magnet motor.

[0026] In any of the above technical solutions, the two permanent magnets in the same group are arranged at intervals.

[0027] In this technical solution, two permanent magnets in the same group are symmetrically distributed in a V-shape on both sides of the first plane, with a gap between them. This gap between the two permanent magnets serves two purposes: firstly, it allows the formation of multiple independent magnetic circuits within the permanent magnets, optimizing the magnetic circuit distribution in the rotor assembly; secondly, the gap between the two permanent magnets acts as a magnetic isolation mechanism, preventing interference between adjacent permanent magnets and thus improving the stability of the rotor assembly.

[0028] In any of the above technical solutions, the permanent magnet further includes: a second diffusion section, which is connected to the second end of the non-diffusion section.

[0029] In this technical solution, the permanent magnet also includes a second diffusion section. Specifically, the second diffusion section is located at the second end of the non-diffusion section near the centerline of the rotor core, and the second diffusion section and part of the non-diffusion section are arranged side by side in the first direction. By providing the second diffusion section, two anti-demagnetization regions can be formed in the central region of the two permanent magnets that are distributed in a V-shape, so that the non-diffusion section is arranged between the first diffusion section and the second diffusion section, thereby enhancing the anti-demagnetization capability of the permanent magnet.

[0030] Specifically, because the mass proportion of heavy metal elements in the second diffusion section is greater than that in the non-diffusion section, the coercivity of the two anti-demagnetization regions in the middle is greater than that of the non-diffusion regions on both sides. When a magnetic material is saturated with magnetization, its magnetic flux density does not return to zero when the external magnetic field returns to zero. Only when a magnetic field of a certain magnitude is applied in the opposite direction of the original magnetization field can the magnetic flux density return to zero; this magnetic field becomes the coercivity. Therefore, the second diffusion section can resist a stronger coercive magnetic field than the non-diffusion section, thus maintaining its own magnetic flux density when the non-diffusion section faces the risk of demagnetization, thereby preventing irreversible demagnetization in the non-diffusion section. This achieves the technical effect of improving the demagnetization resistance of the permanent magnet, extending the service life of the rotor assembly, and improving the reliability of the rotor assembly.

[0031] In any of the above technical solutions, the rotor assembly further includes: a second magnetic isolation bridge, located between two second diffusers in the same group, and connected to the two diffusers in the same group.

[0032] In this technical solution, a second magnetic isolation bridge is also provided on the rotor assembly. The second magnetic isolation bridge is positioned between two permanent magnets in the same group, and its two ends are respectively connected to the second diffusion sections on the two permanent magnets in the same group. By placing the second magnetic isolation bridge between the two second diffusion sections, magnetic leakage can be avoided in the area between the two permanent magnets in the same group. Therefore, by setting the second magnetic isolation bridge, the possibility of magnetic circuit disorder and magnetic leakage within the rotor assembly can be effectively reduced. This achieves the technical effect of optimizing the rotor assembly structure and improving the practicality and reliability of the rotor assembly.

[0033] In any of the above technical solutions, the minimum length of the second magnetic isolation bridge in the tangential direction of the rotor core is W2; the length of the second diffusion section in the extending direction is L2; ​​wherein, W2 1.2 ×L2=K2, 0.75≤K2≤2.70, where K2 is the second dimension ratio.

[0034] In this technical solution, the dimensional relationship between the second magnetic isolation bridge and the second diffusion section is defined. Specifically, in the tangential direction of the rotor core, the minimum length of the second magnetic isolation bridge is W2. Specifically, when the second magnetic isolation bridge fills the gap between adjacent end faces of two permanent magnets in the same group, W2 is the minimum gap between the two permanent magnets. Based on this, the length of the second diffusion section in the extension direction of the permanent magnet is L2, and W2 and L2 satisfy the following relationship: W2 1.2 ×L2=K2,0.75≤K2≤2.70. By limiting the above dimensional relationships, the local anti-demagnetization ability of the magnet can be improved while ensuring demagnetization reliability and without increasing the magnet volume. This, in turn, improves the anti-demagnetization ability of the rotor assembly and reduces the cost of the rotor assembly.

[0035] In any of the above technical solutions, the mass percentage of heavy metal elements in the second diffusion section is greater than the mass percentage of heavy metal elements in the first diffusion section.

[0036] In this technical solution, the mass percentage of heavy metal elements in the second diffusion section is greater than that in the first diffusion section, meaning the coercivity of the second diffusion section is greater than that of the first diffusion section. By setting first and second diffusion sections with different mass percentages of heavy metal elements, first and second diffusion regions with different demagnetization resistance can be formed on each permanent magnet. This gradient demagnetization resistance enhances the demagnetization resistance of the rotor assembly, thereby reducing the probability of irreversible demagnetization problems in the rotor assembly.

[0037] In any of the above technical solutions, the mass percentage of heavy metal elements in the second diffusion section is greater than or equal to 0.4 and less than or equal to 0.75.

[0038] In this technical solution, the mass percentage of heavy metal elements in the second diffusion section is limited. Specifically, the mass percentage of heavy metal elements in the second diffusion section must be greater than or equal to 0.4 and less than or equal to 0.75. By limiting the mass percentage of heavy metal elements in the second diffusion section to greater than 0.4, it can be ensured that the second diffusion section has greater coercivity than the non-diffusion section, thereby ensuring that the second diffusion section can improve the demagnetization resistance of the entire permanent magnet. By limiting the mass percentage of heavy metal elements in the second diffusion section to less than 0.75, the production cost of the permanent magnet can be reduced while ensuring that the second diffusion section has strong demagnetization resistance, thereby meeting the low-cost requirements of permanent magnet motors and enhancing the market competitiveness of the product.

[0039] In any of the above technical solutions, the first magnetic isolation bridge and the air gap are used.

[0040] In this technical solution, the first magnetic isolation bridge is an air gap. Specifically, the first magnetic isolation bridge and the through hole are processed and formed simultaneously. The gap between the permanent magnet and the inner wall of the hole structure forms the aforementioned first and second magnetic isolation bridges. The second magnetic isolation bridge is made of silicon steel and can be integrally formed with the silicon steel stator lamination.

[0041] In any of the above technical solutions, the permanent magnet is radially magnetized or the permanent magnet is parallelly magnetized.

[0042] In this technical solution, the magnetization direction of the permanent magnet can be radial or parallel. To achieve this, the magnetization direction of the multiple permanent magnets on the rotor assembly is kept consistent, and the magnetization directions of the first diffusion section, second diffusion section, and non-diffusion section within each permanent magnet are also consistent. When the non-diffusion section demagnetizes due to an external magnetic field, the first and second diffusion sections, which have stronger resistance to demagnetization, can maintain their own magnetism. Therefore, the first and second diffusion sections magnetize the non-diffusion section, preventing irreversible demagnetization of the permanent magnet.

[0043] In any of the above technical solutions, the heavy metal elements in the diffusion section are uniformly distributed in the magnetization direction of the permanent magnet.

[0044] In this technical solution, heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet in both the first and second diffusion sections. By uniformly distributing the heavy metal elements in the diffusion sections along the magnetization direction, the uniformity of the anti-demagnetization region on the permanent magnet can be improved, thereby further reducing the probability of irreversible demagnetization of the permanent magnet.

[0045] The second aspect of this application discloses a permanent magnet motor, which includes a rotor assembly as described in any of the above technical solutions.

[0046] This technical solution proposes a permanent magnet motor equipped with the rotor assembly described in any of the aforementioned technical solutions. Therefore, this permanent magnet motor possesses the advantages of the rotor assembly in any of the aforementioned technical solutions and can achieve the technical effects achievable by the rotor assembly in any of the aforementioned technical solutions. To avoid repetition, further details are omitted here.

[0047] The third aspect of this application proposes a compressor, which includes a permanent magnet motor as described in the above technical solution.

[0048] This technical solution proposes a compressor equipped with the permanent magnet motor described above, which can be applied to inverter air conditioners. Therefore, the compressor possesses the advantages of the permanent magnet motor described in the above technical solution and can achieve the technical effects achievable by the permanent magnet motor described above. To avoid repetition, further details are omitted here.

[0049] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0050] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0051] Figure 1 One of the schematic diagrams of a rotor assembly according to an embodiment of the present invention is shown;

[0052] Figure 2 A second schematic diagram of the structure of a rotor assembly according to an embodiment of the present invention is shown;

[0053] Figure 3 The third schematic diagram of a rotor assembly according to an embodiment of the present invention is shown.

[0054] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0055] 100 Rotor assembly, 110 Rotor core, 120 Permanent magnet, 122 Non-diffusion section, 124 First diffusion section, 126 Second diffusion section, 130 First magnetic isolation bridge, 140 Second magnetic isolation bridge. Detailed Implementation

[0056] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0057] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0058] The following reference Figures 1 to 3 The present invention describes rotor assemblies, permanent magnet motors, and compressors according to some embodiments thereof.

[0059] Example 1

[0060] like Figure 1 , Figure 2 and Figure 3 As shown, a first aspect of the present invention provides a rotor assembly 100, the rotor assembly 100 comprising:

[0061] The rotor core 110 includes a through hole; a permanent magnet 120 is disposed in the through hole. A first cross-section is obtained by cutting the permanent magnet 120 through a plane perpendicular to the axis of the rotor core 110. On the first cross-section, the extending direction of the permanent magnet 120 is ( Figure 3 The angle between the B-direction (which is the extension direction) and the radial direction of the rotor core 110 is greater than 0° and less than 90°. The permanent magnet 120 includes: a non-diffusion portion 122, which includes a first end and a second end in the extension direction, the first end being adjacent to the circumferential side surface of the rotor core 110 and the second end being adjacent to the axis of the rotor core 110; a first diffusion portion 124, which is connected to the first end of the non-diffusion portion 122; and a first magnetic isolation bridge 130, which is connected to the first diffusion portion 124 and located between the first diffusion portion 124 and the circumferential side surface of the rotor core 110. The mass percentage of heavy metal elements in the first diffusion portion 124 is greater than the mass percentage of heavy metal elements in the non-diffusion portion 122.

[0062] This application defines a rotor assembly 100 for use in a permanent magnet motor. Specifically, the rotor assembly 100 includes a rotor core 110 and a permanent magnet 120. The rotor core 110 is formed by stacking multiple rotor laminations, each lamination having an opening at a corresponding position. Aligning and stacking the openings of the multiple rotor laminations together forms an axial through-hole in the rotor core 110. The permanent magnet 120 is inserted into the through-hole, the shape of which matches the outer contour of the permanent magnet 120, wherein the permanent magnet 120 is used to provide excitation.

[0063] In related technologies, various products demand high power density and low cost from permanent magnet motors. This requirement limits the design of permanent magnet motors, leading to technical problems such as weak demagnetization resistance and susceptibility to irreversible demagnetization. Irreversible demagnetization can cause the permanent magnet motor and related products to fail, directly impacting product lifespan and negatively affecting the user experience.

[0064] In the embodiments defined in this application, the permanent magnet 120 is divided into a non-diffusion portion 122 and a diffusion portion by adjusting the heavy metal element content in a local area. Specifically, on the permanent magnet 120, the diffusion portion and at least a portion of the non-diffusion portion 122 are arranged side by side in a first direction. This first direction is perpendicular to the axial direction of the rotor core 110; that is, by cutting the permanent magnet 120 with a plane perpendicular to the rotor core 110, the diffusion portion and the non-diffusion portion 122 arranged side by side can be obtained simultaneously on the cut surface.

[0065] The permanent magnet 120 is cut into a plane perpendicular to the axis of the stator core to obtain a first cross-section. In this first cross-section, the extending direction of the permanent magnet 120 is inclined to the radial direction of the rotor core 110, with an inclination angle less than 90°. In the extending direction of the permanent magnet 120, the non-diffusion portion 122 includes a first end and a second end. The first end is near the circumferential surface of the stator core, and the second end is near the centerline of the stator core. Furthermore, the diffusion portion includes a first diffusion portion 124, which is connected to the first end of the non-diffusion portion 122. In the non-diffusion portion, the ratio of the mass of heavy metal elements to the total mass of the diffusion portion is called the mass percentage of metal elements in the diffusion portion, g1. Correspondingly, in the first diffusion portion 124, the ratio of the mass of heavy metal elements to the total mass of the non-diffusion portion 122 is called the mass percentage of metal elements in the non-diffusion portion 122, g2, where g2 is greater than g1.

[0066] By limiting the mass ratio of heavy metal elements in the first diffusion section 124 to be greater than that in the non-diffusion section 122, it can be ensured that the coercivity of the first diffusion section 124, which is arranged side-by-side in the first direction, is greater than that of the non-diffusion section 122. This forms a diffusion zone with strong demagnetization resistance in a certain area of ​​the permanent magnet 120, thereby improving the local demagnetization resistance of the permanent magnet 120 and enhancing the overall demagnetization resistance of the rotor assembly 100. This reduces the possibility of irreversible demagnetization in the rotor assembly 100, ensuring reliable operation of the permanent magnet motor and related products over a long period and extending the product's service life.

[0067] Therefore, the rotor assembly 100 defined in this application solves the technical problems existing in related technologies, such as the weak demagnetization resistance and susceptibility to irreversible demagnetization in permanent magnet motors. Simultaneously, this structure can improve the demagnetization resistance of the rotor assembly 100 without increasing the volume of the permanent magnet 120, thus balancing the high power density and low cost requirements of permanent magnet motors. This further optimizes the structure of the rotor assembly 100, improves its reliability, extends its service life, and reduces the product failure rate.

[0068] Based on this, the rotor assembly 100 is also provided with a first magnetic isolation bridge 130, which is connected to the first diffusion section 124 and located between the peripheral side of the rotor core 110 and the first diffusion section 124. The first magnetic isolation bridge 130 can play a certain role in magnetic isolation, and by setting the first magnetic isolation bridge 130, the possibility of magnetic circuit disorder and magnetic leakage problems inside the rotor assembly 100 can be effectively reduced. This achieves the technical effect of optimizing the structure of the rotor assembly 100 and improving its practicality and reliability.

[0069] Example 2

[0070] like Figure 1 , Figure 2 and Figure 3 As shown in the second aspect embodiment of the present invention, the distance between the first magnetic isolation bridge 130 and the peripheral side surface of the rotor core 110 in the radial direction is W1; the length of the first diffusion portion 124 in the extending direction is L1, wherein W1 1.3 ×L1=K1, 0.04≤K1≤0.57.

[0071] In this embodiment, the dimensional relationship between the first magnetic isolation bridge 130 and the first diffusion portion 124 is defined. Specifically, the distance between the first magnetic isolation bridge 130 and the peripheral surface of the rotor core 110 is W1, that is, the minimum distance between the first magnetic isolation bridge 130 and the peripheral surface of the rotor core 110 in the radial direction is W1. In the first cross-section, the length of the first diffusion portion 124 in the extending direction of the permanent magnet 120 is L1. Based on this, W1 and L1 satisfy the following relationship, W1 1.3 ×L1=K1, 0.04≤K1≤0.57. By limiting the above dimensional relationship, the local anti-demagnetization ability of the magnet can be improved while ensuring demagnetization reliability and without increasing the magnet volume, thereby improving the anti-demagnetization ability of the rotor assembly 100 and reducing the cost of the rotor assembly 100.

[0072] In any of the above embodiments, the mass percentage of heavy metal elements in the first diffusion section 124 is greater than or equal to 0.6 and less than or equal to 0.8.

[0073] In this embodiment, the range of the mass percentage of heavy metal elements in the first diffusion section 124 is limited. Specifically, the mass percentage of heavy metal elements in the first diffusion section 124 must be greater than or equal to 0.6 and less than or equal to 0.8. By limiting the mass percentage of heavy metal elements in the first diffusion section 124 to be greater than 0.6, it can be ensured that the first diffusion section 124 has a greater coercivity than the non-diffusion section 122, thereby ensuring that the first diffusion section 124 can improve the demagnetization resistance of the entire permanent magnet 120. By limiting the mass percentage of heavy metal elements in the first diffusion section 124 to be less than 0.8, the production cost of the permanent magnet 120 can be reduced while ensuring that the first diffusion section 124 has a strong demagnetization resistance, thereby meeting the low-cost requirements of the permanent magnet motor and improving the market competitiveness of the product.

[0074] Example 3

[0075] like Figure 1 , Figure 2 and Figure 3As shown in the third aspect embodiment of the present invention, two permanent magnets 120 form a group, and the rotor assembly 100 includes multiple groups of permanent magnets 120; on the first cross section, the two permanent magnets 120 in the same group are distributed in a V-shape.

[0076] In this embodiment, the layout of the permanent magnets 120 on the rotor assembly 100 is defined. Specifically, each rotor assembly 100 is provided with multiple sets of permanent magnets 120, which are arranged around the axis of the rotor core 110. Each set of permanent magnets 120 includes two permanent magnets 120, which are symmetrically arranged on both sides of a first plane. The axis and diameter of the rotor core 110 are both within the first plane. Specifically, the rotor core 110 and the permanent magnets 120 are cut off by a plane perpendicular to the axis of the rotor core 110, and the diameter of the rotor core 110 in this cross-section is the first plane.

[0077] By arranging multiple sets of permanent magnets 120 on the rotor assembly 100, the demagnetization resistance of the rotor assembly 100 can be enhanced, thereby further reducing the possibility of irreversible demagnetization. Furthermore, by symmetrically distributing two permanent magnets 120 in each set on both sides of the first plane, multiple areas with strong demagnetization resistance can be formed on the circumference of the rotor core 110 shaft, thus improving the overall demagnetization resistance of the rotor core 110. This achieves the technical effect of improving the reliability of the rotor assembly 100 and extending its service life.

[0078] In each group of permanent magnets 120, two permanent magnets 120 are arranged in a V-shape on both sides of the first plane. Specifically, the permanent magnets 120 are cut through a plane perpendicular to the axis of the rotor core 110. In this cross-section, the two permanent magnets 120 located in the same group have an angle with the first plane, the angle of which is less than 90°, to form two permanent magnets 120 arranged in a V-shape. The opening of the two permanent magnets 120 arranged in the V-shape can face the axis of the rotor core 110 or face the outside of the rotor core 110; this embodiment does not impose a strict limitation on this.

[0079] By distributing the two permanent magnets 120 in a V-shape within the same group, a hybrid magnetic circuit structure can be formed in the rotor assembly 100. This hybrid magnetic circuit structure improves the steady-state and dynamic performance of the rotor assembly 100, helps increase the power density and overload capacity of the permanent magnet motor, and facilitates field weakening for speed extension. Furthermore, it increases the coverage area of ​​the permanent magnets 120 in the circumferential direction of the rotor core 110, thereby enhancing the performance of the permanent magnet motor.

[0080] In any of the above embodiments, the two permanent magnets 120 in the same group are arranged at intervals.

[0081] In this embodiment, two permanent magnets 120 in the same group are symmetrically distributed in a V-shape on both sides of the first plane, with a gap between them. This gap between the two permanent magnets 120 allows for the formation of multiple independent magnetic circuits within each permanent magnet 120, optimizing the magnetic circuit distribution in the rotor assembly 100. Furthermore, the gap between the two permanent magnets 120 serves as a magnetic isolation mechanism, preventing interference between adjacent permanent magnets 120 and thus improving the stability of the rotor assembly 100.

[0082] Example 4

[0083] like Figure 1 , Figure 2 and Figure 3 As shown in the fourth aspect embodiment of the present invention, the permanent magnet 120 further includes: a second diffusion portion 126, which is connected to the second end of the non-diffusion portion 122.

[0084] In this embodiment, the permanent magnet 120 further includes a second diffusion section 126. Specifically, the second diffusion section 126 is located at the second end of the non-diffusion section 122 near the centerline of the rotor core 110, and the second diffusion section 126 and a portion of the non-diffusion section 122 are arranged side by side in the first direction. By providing the second diffusion section 126, two anti-demagnetization regions can be formed in the central region of the two permanent magnets 120, which are distributed in a V-shape, so that the non-diffusion section 122 is arranged between the first diffusion section 124 and the second diffusion section 126, thereby enhancing the anti-demagnetization capability of the permanent magnet 120.

[0085] Specifically, because the mass ratio of heavy metal elements in the second diffusion section 126 is greater than that in the non-diffusion section 122, the coercivity of the two anti-demagnetization regions in the middle is greater than that of the non-diffusion regions on both sides. When a magnetic material is saturated with magnetization, its magnetic flux density does not return to zero when the external magnetic field returns to zero. Only when a magnetic field of a certain magnitude is applied in the opposite direction of the original magnetization field can the magnetic flux density return to zero; this magnetic field becomes the coercivity. Therefore, the strength of the coercive magnetic field that the second diffusion section 126 can resist is greater than that that that the non-diffusion section 122 can resist. This allows the non-diffusion section 122 to maintain its own magnetic flux density when facing the risk of demagnetization, thereby preventing irreversible demagnetization. This achieves the technical effect of improving the demagnetization resistance of the permanent magnet 120, extending the service life of the rotor assembly 100, and improving the reliability of the rotor assembly 100.

[0086] In any of the above embodiments, the rotor assembly 100 further includes a second magnetic isolation bridge 140, located between two second diffusers 126 in the same group, and connected to the two diffusers in the same group.

[0087] In this embodiment, a second magnetic isolation bridge 140 is also provided on the rotor assembly 100. The second magnetic isolation bridge 140 is disposed between two permanent magnets 120 in the same group, and both ends of the second magnetic isolation bridge 140 are respectively connected to the second diffusion portions 126 on the two permanent magnets 120 in the same group. By providing the second magnetic isolation bridge 140 between the two second diffusion portions 126, magnetic leakage problems can be avoided in the area between the two permanent magnets 120 in the same group. Therefore, by providing the second magnetic isolation bridge 140, the possibility of magnetic circuit disorder and magnetic leakage problems inside the rotor assembly 100 can be effectively reduced. This achieves the technical effect of optimizing the structure of the rotor assembly 100 and improving its practicality and reliability.

[0088] In any of the above embodiments, the minimum length of the second magnetic isolation bridge 140 in the tangential direction of the rotor core 110 is W2; the length of the second diffusion portion 126 in the extending direction is L2; ​​wherein, W2 1.2 ×L2=K2, 0.75≤K2≤2.70.

[0089] In this embodiment, the dimensional relationship between the second magnetic isolation bridge 140 and the second diffusion portion 126 is defined. Specifically, in the tangential direction of the rotor core 110, the minimum length of the second magnetic isolation bridge 140 is W2. Specifically, when the second magnetic isolation bridge 140 fills the gap between adjacent end faces of two permanent magnets 120 in the same group, W2 is the minimum gap between the two permanent magnets 120. Based on this, the length of the second diffusion portion 126 in the extending direction of the permanent magnet 120 is L2, and W2 and L2 satisfy the following relationship: W2 1.2 ×L2=K2, 0.75≤K2≤2.70.

[0090] By limiting the above dimensional relationships, the local anti-demagnetization ability of the magnet can be improved without increasing the magnet volume, thereby improving the anti-demagnetization ability of the rotor assembly 100 and reducing the cost of the rotor assembly 100.

[0091] In any of the above embodiments, the mass percentage of heavy metal elements in the second diffusion section 126 is greater than the mass percentage of heavy metal elements in the first diffusion section 124.

[0092] In this embodiment, the mass percentage of heavy metal elements in the second diffusion section 126 is greater than that in the first diffusion section 124, meaning the coercivity of the second diffusion section 126 is greater than that of the first diffusion section 124. By providing first diffusion sections 124 and second diffusion sections 126 with different mass percentages of heavy metal elements, first diffusion regions and second diffusion regions with different demagnetization resistance can be formed on each permanent magnet 120. This gradient demagnetization resistance enhances the demagnetization resistance of the rotor assembly 100, thereby reducing the probability of irreversible demagnetization in the rotor assembly 100.

[0093] In any of the above embodiments, the mass percentage of heavy metal elements in the second diffusion section 126 is greater than or equal to 0.4 and less than or equal to 0.75.

[0094] In this embodiment, the range of the mass percentage of heavy metal elements in the second diffusion section 126 is limited. Specifically, the mass percentage of heavy metal elements in the second diffusion section 126 must be greater than or equal to 0.4 and less than or equal to 0.75. By limiting the mass percentage of heavy metal elements in the second diffusion section 126 to be greater than 0.4, it can be ensured that the second diffusion section 126 has a greater coercivity than the non-diffusion section 122, thereby ensuring that the second diffusion section 126 can improve the demagnetization resistance of the entire permanent magnet 120. By limiting the mass percentage of heavy metal elements in the second diffusion section 126 to less than 0.75, the production cost of the permanent magnet 120 can be reduced while ensuring that the second diffusion section 126 has a strong demagnetization resistance, thereby meeting the low-cost requirements of the permanent magnet motor and improving the market competitiveness of the product.

[0095] Example 5

[0096] like Figure 1 , Figure 2 and Figure 3 As shown in the fifth aspect embodiment of the present invention, the first magnetic bridge 130 is an air gap.

[0097] In this embodiment, the first magnetic isolation bridge 130 is an air gap. Specifically, the first magnetic isolation bridge 130 is processed and formed simultaneously with the through hole. The gap between the permanent magnet 120 and the inner wall of the hole structure forms the aforementioned first magnetic isolation bridge 130 and second magnetic isolation bridge 140. The second magnetic isolation bridge 140 is made of silicon steel and can be integrally formed with the silicon steel stator lamination.

[0098] In any of the above embodiments, the permanent magnet 120 is radially magnetized or the permanent magnet 120 is parallel magnetized.

[0099] In this embodiment, the magnetization direction of the permanent magnet 120 can be radial or parallel. To achieve this, the magnetization directions of the multiple permanent magnets 120 on the rotor assembly 100 are kept consistent, and the magnetization directions of the first diffusion portion 124, the second diffusion portion 126, and the non-diffusion portion in each permanent magnet 120 are also consistent. When the non-diffusion portion 122 demagnetizes due to an external magnetic field, the first diffusion portion 124 and the second diffusion portion 126, which have strong anti-demagnetization capabilities, can still maintain their own magnetism. Therefore, the non-diffusion portion 122 is magnetized by the first diffusion portion 124 and the second diffusion portion 126 to avoid irreversible demagnetization of the permanent magnet 120.

[0100] In any of the above embodiments, in the diffusion section, the heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet 120.

[0101] In this embodiment, heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet 120 in the first diffusion section 124 and the second diffusion section 126. By uniformly distributing heavy metal elements in the diffusion sections in the magnetization direction, the uniformity of the anti-demagnetization region distribution on the permanent magnet 120 can be improved, thereby further reducing the probability of irreversible demagnetization of the permanent magnet 120.

[0102] Example 6

[0103] like Figure 1 , Figure 2 and Figure 3 As shown in the sixth aspect embodiment of the present invention, the permanent magnet 120 is cut by a plane perpendicular to the rotor core 110; on the cross section, the area of ​​the first diffusion portion 124 is S1, and the area of ​​the permanent magnet 120 is S3; the ratio of S1 to S3 is greater than or equal to 0.1 and less than or equal to 0.4.

[0104] In this embodiment, the dimensional relationship between the first diffusion portion 124 and the non-diffusion portion 122 is defined. Specifically, the permanent magnet 120 extends in the through hole parallel to the axis of the rotor core 110. Based on this, by cutting the permanent magnet 120 with a plane perpendicular to the axis of the rotor core 110, the cross-sections of the first diffusion portion 124 and the non-diffusion portion 122 can be obtained on the cross-section. The area of ​​the cross-section of the first diffusion portion 124 is S1, and the area of ​​the cross-section of the permanent magnet 120 is S3, wherein the ratio of S1 to S3 must be greater than or equal to 0.1 and less than or equal to 0.4. Figure 3 In the diagram, direction A represents the width of the permanent magnet, and direction B represents its extension direction, i.e., its length. The product of the length and the width gives the area.

[0105] When the first diffusion section 124 and the non-diffusion section 122 are arranged side by side along the first direction, the ratio between the cross-sectional area of ​​the first diffusion section 124 and the cross-sectional area of ​​the permanent magnet 120 can reflect the relative size relationship between the first diffusion section 124 and the non-diffusion section 122. By limiting the ratio of S1 to S3 to be greater than or equal to 0.1, the situation where the size of the first diffusion section 124 is too small and cannot provide effective anti-demagnetization support for the non-diffusion section 122 can be avoided, thereby ensuring the overall anti-demagnetization capability of the permanent magnet 120. By limiting the ratio of S1 to S3 to be less than or equal to 0.4, the amount of heavy metal elements can be reduced while ensuring the anti-demagnetization capability of the permanent magnet 120, thereby compressing the cost of the permanent magnet 120 and balancing the anti-demagnetization requirements and low-cost requirements of the permanent magnet motor. This achieves the technical effects of optimizing the structural layout of the permanent magnet 120, improving the reliability of the permanent magnet 120, extending the life of the permanent magnet 120, and enhancing the product's market competitiveness.

[0106] In any of the above embodiments, the permanent magnet 120 is cut by a plane perpendicular to the rotor core 110; on the cross section, the area of ​​the second diffuser 126 is S2, and the area of ​​the permanent magnet 120 is S3; the ratio of S2 to S3 is greater than or equal to 0.1 and less than or equal to 0.4.

[0107] In this embodiment, the dimensional relationship between the second diffusion section 126 and the non-diffusion section 122 is defined. Specifically, the permanent magnet 120 extends in the through hole along the through hole parallel to the axis of the rotor core 110. Based on this, by cutting the permanent magnet 120 through a plane perpendicular to the axis of the rotor core 110, the cross-section of the permanent magnet 120 can be obtained. The area of ​​the cross-section of the second diffusion section 126 is S2, and the area of ​​the cross-section of the permanent magnet 120 is S3. The ratio of S2 to S3 must be greater than or equal to 0.1 and less than or equal to 0.4.

[0108] When the second diffuser 126 and the non-diffusion part 122 are arranged side by side along the first direction, the ratio of the cross-sectional area of ​​the second diffuser 126 to the cross-sectional area of ​​the permanent magnet 120 reflects the relative dimensional relationship between the second diffuser 126 and the non-diffusion part 122. By limiting the ratio of S2 to S3 to be greater than or equal to 0.1, the situation where the second diffuser 126 is too small to provide effective anti-demagnetization support for the non-diffusion part 122 can be avoided, thus ensuring the overall anti-demagnetization capability of the permanent magnet 120. By limiting the ratio of S2 to S3 to be less than or equal to 0.4, the amount of heavy metal elements can be reduced while ensuring the anti-demagnetization capability of the permanent magnet 120, thereby compressing the cost of the permanent magnet 120 and balancing the anti-demagnetization requirements and low-cost requirements of the permanent magnet motor. This achieves the technical effects of optimizing the structural layout of the permanent magnet 120, improving the reliability of the permanent magnet 120, extending the life of the permanent magnet 120, and enhancing the product's market competitiveness.

[0109] A second aspect of this application provides a permanent magnet motor, which includes a rotor assembly 100 as described in any of the above embodiments.

[0110] In this embodiment, a permanent magnet motor is proposed, which is equipped with the rotor assembly 100 of any of the above embodiments. Therefore, this permanent magnet motor possesses the advantages of the rotor assembly 100 of any of the above embodiments. It can achieve the technical effects achievable by the rotor assembly 100 of any of the above embodiments. To avoid repetition, further details are omitted here.

[0111] A third aspect of this application discloses a compressor comprising a permanent magnet motor as described in the above embodiments.

[0112] This embodiment proposes a compressor equipped with the permanent magnet motor described in the above embodiments, which can be applied to inverter air conditioners. Therefore, the compressor possesses the advantages of the permanent magnet motor described in the above embodiments and can achieve the technical effects achievable by the permanent magnet motor described in the above embodiments. To avoid repetition, further details are omitted here.

[0113] It should be clarified that in the claims, description, and accompanying drawings of this invention, the term "plural" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description process, not to indicate or imply that the device or element referred to must have the described specific orientation, or be constructed and operated in a specific orientation. Therefore, these descriptions should not be construed as limiting the invention. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection between multiple objects, a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects or an indirect connection between multiple objects through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this invention can be understood based on the specific circumstances of the above data.

[0114] In the claims, description, and accompanying drawings of this invention, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In the claims, description, and accompanying drawings of this invention, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0115] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rotor assembly, characterized in that, include: Rotor core, including through holes; A permanent magnet is disposed in the through hole. A first cross-section is obtained by cutting the permanent magnet through a plane perpendicular to the axis of the rotor core. On this first cross-section, the angle between the extending direction of the permanent magnet and the radial direction of the rotor core is greater than 0° and less than 90°. The permanent magnet comprises: The non-diffusion portion, in the extending direction, includes a first end and a second end, the first end being adjacent to the circumferential side surface of the rotor core, and the second end being adjacent to the axis of the rotor core. The first diffusion section is connected to the first end of the non-diffusion section; The first magnetic isolation bridge is connected to the first diffusion section and is located between the first diffusion section and the peripheral side surface of the rotor core. Wherein, the mass percentage of heavy metal elements in the first diffusion section is greater than the mass percentage of heavy metal elements in the non-diffusion section; In the radial direction of the rotor core, the distance between the first magnetic isolation bridge and the peripheral side surface of the rotor core is W1; The length of the first diffusion portion in the extending direction is L1; in, , K1 is the first size ratio.

2. The rotor assembly according to claim 1, characterized in that, The mass percentage of heavy metal elements in the first diffusion section is greater than or equal to 0.6 and less than or equal to 0.

8.

3. The rotor assembly according to claim 1, characterized in that, Two permanent magnets form a group, and the rotor assembly includes multiple groups of permanent magnets; On the first cross section, the two permanent magnets in the same group are arranged in a V-shape.

4. The rotor assembly according to claim 3, characterized in that, The two permanent magnets in the same group are spaced apart.

5. The rotor assembly according to claim 4, characterized in that, The permanent magnet also includes: The second diffusion section is connected to the second end of the non-diffusion section.

6. The rotor assembly according to claim 5, characterized in that, Also includes: The second magnetic isolation bridge is located between the two second diffusion sections in the same group and is connected to the two diffusion sections in the same group.

7. The rotor assembly according to claim 6, characterized in that, In the tangential direction of the rotor core, the minimum length of the second magnetic bridge is W2; The length of the second diffusion portion in the extending direction is L2; in, , K2 is the second size ratio.

8. The rotor assembly according to claim 7, characterized in that, The mass percentage of heavy metal elements in the second diffusion section is greater than that in the first diffusion section.

9. The rotor assembly according to claim 8, characterized in that, The mass percentage of heavy metal elements in the second diffusion section is greater than or equal to 0.4 and less than or equal to 0.

75.

10. The rotor assembly according to claim 6, characterized in that, The first and second magnetic isolation bridges are air gaps.

11. The rotor assembly according to any one of claims 1 to 10, characterized in that, The permanent magnet is radially magnetized, or the permanent magnet is parallelly magnetized.

12. The rotor assembly according to claim 11, characterized in that, In the diffusion section, the heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet.

13. A permanent magnet motor, characterized in that, include: The rotor assembly as described in any one of claims 1 to 12.

14. A compressor, characterized in that, include: The permanent magnet motor as described in claim 13.

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