Rotor assemblies, permanent magnet motors and compressors

Abstract

This application provides a rotor assembly, a permanent magnet motor, and a compressor. The rotor assembly includes a rotor core having a through hole, and a permanent magnet, the permanent magnet being disposed in the through hole, the permanent magnet being cut along a plane perpendicular to the axis of the rotor core to obtain a first cross section, and the angle between the extension direction of the permanent magnet and the radial direction of the rotor core in the first cross section is greater than 0° and less than 90°, the permanent magnet includes a non-diffusion part including a first end close to the circumferential side of the rotor core and a second end close to the axis of the rotor core in the extension direction, a first diffusion part in contact with the first end of the non-diffusion part, and a first magnetic insulating bridge in contact with the first diffusion part and located between the first diffusion part and the circumferential side of the rotor core, where the mass occupancy of the heavy metal elements in the first diffusion part is greater than the mass occupancy of the heavy metal elements in the non-diffusion part. This application solves the technical problem that the permanent magnet motor has poor anti-demagnetization performance and is prone to irreversible demagnetization.

Description

[Technical field]

[0001] This application claims priority to a Chinese patent application bearing application number 202210460906.6 and entitled "ROTOR ASSEMBLY, PERMANENT MAGNET MOTOR AND COMPRESSOR" filed with the State Intellectual Property Office of the People's Republic of China on April 28, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of compressors, and more particularly to rotor assemblies, permanent magnet motors and compressors. [Background technology]

[0003] At present, air conditioning compressors at home and abroad basically adopt inverter motors, which generally adopt permanent magnet motors, and the excitation method of the rotor of the permanent magnet motor is excitation by permanent magnets. Summary of the Invention [Problem to be solved by the invention]

[0004] Due to the high power density characteristics of current permanent magnet motors and the demand for cost reduction, the demagnetization resistance performance of the rotor permanent magnet is declining. When irreversible demagnetization occurs in a permanent magnet, it affects the operating performance and reliability of the motor and compressor, and seriously affects the service life of the product. Therefore, how to design a rotor assembly that can effectively solve the above technical shortcomings has become an urgent technical problem to be solved. [Means for solving the problem]

[0005] The present application aims to solve at least one of the technical problems existing in the prior art.

[0006] To this end, in a first aspect of the present application, a rotor assembly is proposed.

[0007] In a second aspect of the present application, a permanent magnet motor is proposed.

[0008] In a third aspect of the present application, a compressor is proposed.

[0009] In view of this, a first aspect of the present application provides a rotor assembly, the rotor assembly including: a rotor core having a through hole; and a permanent magnet disposed within the through hole, a first cross section being obtained by cutting the permanent magnet along a plane perpendicular to the axis of the rotor core, the angle between an extension direction of the permanent magnet and a radial direction of the rotor core in the first cross section being greater than 0° and smaller than 90°, the permanent magnet including, in the extension direction, a non-diffusion portion including a first end close to a circumferential side surface of the rotor core and a second end close to the axis of the rotor core, a first diffusion portion in contact with the first end of the non-diffusion portion, and a first magnetic insulating bridge in contact with the first diffusion portion and located between the first diffusion portion and the circumferential side surface of the rotor core, wherein a mass occupancy of heavy metal elements in the first diffusion portion is greater than a mass occupancy of heavy metal elements in the non-diffusion portion.

[0010] In addition, the above rotor assembly provided in the present application may have the following additional technical features.

[0011] In the above technical solution, in the radial direction of the rotor core, the distance between the first magnetic insulating bridge and the peripheral side surface of the rotor core is W1, and the length of the first diffusion part in the extending direction is L1, where W1 1.3 ×L1=K1, 0.04≦K1≦0.57, where K1 is a first dimension ratio.

[0012] In any of the above technical solutions, the mass occupancy rate of the heavy metal element in the first diffusion section is in the range of 0.6 to 0.8.

[0013] In any of the above technical solutions, the permanent magnet further includes a second diffusion portion in contact with the second end of the non-diffusion portion.

[0014] In any of the above technical solutions, the rotor assembly further includes a second magnetic insulating bridge located between and in contact with the two second diffusion portions of the same set.

[0015] In any of the above technical solutions, in the tangential direction of the rotor core, the minimum length of the second magnetic insulating bridge is W2, and the length of the second diffusion part in the extending direction is L2, where W2 1.2 ×L2=K2, 0.75≦K2≦2.70, where K2 is a second dimension ratio.

[0016] In any of the above technical solutions, the mass occupancy of the heavy metal element in the second diffusion section is greater than the mass occupancy of the heavy metal element in the first diffusion section.

[0017] In any of the above technical solutions, the mass occupancy rate of the heavy metal element in the second diffusion section is in the range of 0.4 to 0.75.

[0018] In any of the above technical solutions, the first magnetic isolation bridge and the second magnetic isolation bridge are air gaps.

[0019] In any of the above technical solutions, the permanent magnets are magnetized in a radial direction, or the permanent magnets are magnetized in a parallel direction.

[0020] In any of the above technical solutions, in the first diffusion section, the heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet.

[0021] In a second aspect of the present application, a permanent magnet motor is proposed, which includes a rotor assembly in any of the above technical solutions.

[0022] In the third aspect of the present application, a compressor is proposed, which includes a permanent magnet motor in the above technical solution. Effect of the Invention

[0023] Therefore, the rotor assembly defined in this application solves the technical problem existing in the related art that the permanent magnet motor has poor anti-demagnetization performance and is prone to irreversible demagnetization. At the same time, this structure can improve the anti-demagnetization performance of the rotor assembly without increasing the volume of the permanent magnet, and can balance the high power density and low cost requirements of the permanent magnet motor. Furthermore, the structure of the rotor assembly is optimized, the reliability of the rotor assembly is improved, the service life of the rotor assembly is extended, and the technical effect of reducing the failure rate of the product is achieved.

[0024] Additional aspects and advantages of the present application will be set forth in part in the description which follows, or may be learned by the practice of the present application.

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easier to understand from the following detailed description of the embodiments in conjunction with the drawings, in which: [Brief description of the drawings]

[0026] [Figure 1] FIG. 2 is a first schematic diagram showing a structure of a rotor assembly according to an embodiment of the present application. [Diagram 2] FIG. 2 is a second schematic diagram showing the structure of a rotor assembly according to an embodiment of the present application. [Diagram 3] FIG. 13 is a third schematic diagram showing the structure of a rotor assembly according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In order to make the above-mentioned objects, features and advantages of the present application more clearly comprehensible, the present application will be described in more detail below in conjunction with the drawings and specific embodiments. Note that the embodiments and features in the embodiments in this specification may be combined with each other without contradiction.

[0028] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be implemented in other ways than those described herein, and therefore the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0029] Hereinafter, a rotor assembly, a permanent magnet motor, and a compressor according to some embodiments of the present application will be described with reference to FIGS. 1 to 3. FIG.

[0030] As shown in FIGS. 1, 2 and 3, one embodiment of the present application proposes a rotor assembly 100. As shown in FIG.

[0031] The rotor assembly 100 includes a rotor core 110 having a through hole, and a permanent magnet 120, which is disposed within the through hole, and a first cross section is obtained by cutting the permanent magnet 120 along a plane perpendicular to the axis of the rotor core 110, and in the first cross section, an included angle between an extension direction of the permanent magnet 120 (direction B in FIG. 3 is the extension direction) and a radial direction of the rotor core 110 is greater than 0° and less than 90°. The permanent magnet 120 is arranged such that, in the extension direction, The rotor core 110 includes a non-diffusion portion 122 having a first end adjacent to the circumferential side of the rotor core 110 and a second end adjacent to the axis of the rotor core 110, a first diffusion portion 124 in contact with the first end of the non-diffusion portion 122, and a first magnetic insulating bridge 130 in contact with the first diffusion portion 124 and located between the first diffusion portion 124 and the circumferential side of the rotor core 110, wherein the mass occupancy of heavy metal elements in the first diffusion portion 124 is greater than the mass occupancy of heavy metal elements in the non-diffusion portion 122.

[0032] The present application limits the rotor assembly 100 to be applied to a permanent magnet motor. For example, the rotor assembly 100 includes a rotor core 110 and a permanent magnet 120. The rotor core 110 is formed by stacking a plurality of rotor punching sheets, and each rotor punching sheet has an opening at a corresponding position. By aligning and stacking the openings of the plurality of rotor punching sheets, a through hole penetrating the rotor core 110 along the axial direction can be formed in the rotor core 110. The permanent magnet 120 is inserted into the through hole, and the shape of the through hole is adapted to the outer shape of the permanent magnet 120, and the permanent magnet 120 is used to provide excitation.

[0033] In the related art, various products have put forward the requirements for high power density and low cost for permanent magnet motors, so the design of permanent magnet motors is limited by the above requirements, which leads to the technical problem that permanent magnet motors have poor anti-demagnetization performance and are prone to irreversible demagnetization, which will cause the permanent magnet motor and related products to fail, directly affecting the service life of the products and damaging the user's experience.

[0034] In contrast, in an embodiment limited to the present application, the permanent magnet 120 is divided into a non-diffusion portion 122 and a diffusion portion by adjusting the content of heavy metal elements in a local region of the permanent magnet 120. For example, in the permanent magnet 120, the diffusion portion and at least a part of the non-diffusion portion 122 are arranged side by side in a first direction. Here, the first direction is perpendicular to the axial direction of the rotor core 110, that is, by cutting the permanent magnet 120 on a plane perpendicular to the rotor core 110, the diffusion portion and the non-diffusion portion 122 arranged side by side on the cut surface can be obtained at the same time.

[0035] Here, the first cross section can be obtained by cutting the permanent magnet 120 on a plane perpendicular to the axis of the stator core, and in the first cross section, the extension direction of the permanent magnet 120 is inclined at an inclination angle of less than 90° with respect to the radial direction of the rotor core 110. In the extension direction of the permanent magnet 120, the non-diffusion portion 122 includes a first end close to the peripheral side surface of the stator core and a second end close to the center line of the stator core. In addition, the diffusion portion includes a first diffusion portion 124 in contact with the first end of the non-diffusion portion 122. In the non-diffusion portion 122, the ratio of the mass of the heavy metal element to the mass of the entire non-diffusion portion 122 is the metal element mass occupancy rate g1 of the non-diffusion portion 122. Accordingly, in the first diffusion portion 124, the ratio of the mass of the heavy metal element to the mass of the entire first diffusion portion 124 is the metal element mass occupancy rate g2 of the first diffusion portion 124, and g2 is greater than g1.

[0036] By limiting the heavy metal element mass occupancy rate of the first diffusion portions 124 to be greater than that of the non-diffusion portions 122, it is possible to ensure that the coercive force of the first diffusion portions 124 arranged in parallel in the first direction is greater than that of the non-diffusion portions 122, forming a diffusion region with strong demagnetization resistance in a portion of the permanent magnet 120, which improves the local demagnetization resistance of the permanent magnet 120 and ultimately improves the demagnetization resistance of the entire rotor assembly 100. This reduces the possibility of irreversible demagnetization occurring in the rotor assembly 100, ensures long-term reliable operation of the permanent magnet motor and related products, and extends the service life of the products.

[0037] Therefore, the rotor assembly 100 defined in the present application solves the technical problem existing in the related art that the permanent magnet motor has poor anti-demagnetization performance and is prone to irreversible demagnetization. At the same time, this structure can improve the anti-demagnetization performance of the rotor assembly 100 without increasing the volume of the permanent magnet 120, and can balance the high power density and low cost requirements of the permanent magnet motor. Furthermore, the structure of the rotor assembly 100 is optimized, the reliability of the rotor assembly 100 is improved, the service life of the rotor assembly 100 is extended, and the technical effect of reducing the failure rate of the product is achieved.

[0038] In addition, the rotor assembly 100 is further provided with a first magnetic insulating bridge 130, which is in contact with the first diffusion portion 124 and is located between the peripheral side surface of the rotor core 110 and the first diffusion portion 124. The first magnetic insulating bridge 130 can provide a certain degree of magnetic insulation, and the provision of the first magnetic insulating bridge 130 can effectively reduce the possibility of disturbance of the magnetic circuit and magnetic leakage problems occurring within the rotor assembly 100. Furthermore, the structure of the rotor assembly 100 is optimized, thereby achieving the technical effect of improving the practicability and reliability of the rotor assembly 100.

[0039] As shown in FIGS. 1, 2 and 3, in one embodiment of the present application, in the radial direction of the rotor core 110, the distance between the first magnetic insulating bridge 130 and the circumferential side surface of the rotor core 110 is W1, and the length of the first diffusion portion 124 in the extension direction is L1, where W1 is the distance between the first magnetic insulating bridge 130 and the circumferential side surface of the rotor core 110 and the circumferential side surface of the rotor core 110. 1.3 × L1 = K1, 0.04≦K1≦0.57.

[0040] In this embodiment, the dimensional relationship between the first magnetic isolation bridge 130 and the first diffusion portion 124 is limited. For example, the distance between the first magnetic isolation bridge 130 and the peripheral side surface of the rotor core 110 is W1, that is, the minimum distance between the first magnetic isolation bridge 130 and the peripheral side 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 direction in which the permanent magnet 120 extends is L1. In addition, W1 and L1 satisfy the following relationship. W1 1.3 × L1 = K1, 0.04 ≦ K1 ≦ 0.57. By limiting the above dimensional relationship, it is possible to improve the local demagnetization resistance of the magnet while ensuring demagnetization reliability and without increasing the volume of the magnet, thereby improving the demagnetization resistance of rotor assembly 100 and reducing the cost of rotor assembly 100.

[0041] In any of the above embodiments, the range of the mass occupancy rate of the heavy metal element in the first diffusion portion 124 is equal to or greater than 0.6 and equal to or less than 0.8.

[0042] In this embodiment, the range of the mass occupancy of the heavy metal element in the first diffusion section 124 is limited. For example, the mass occupancy of the heavy metal element in the first diffusion section 124 needs to be 0.6 or more and 0.8 or less. By limiting the mass occupancy of the heavy metal element in the first diffusion section 124 to 0.6 or more, it is guaranteed that the first diffusion section 124 has a larger coercive force than the non-diffusion section 122, and it is ensured that the first diffusion section 124 can improve the demagnetization resistance performance of the entire permanent magnet 120. By limiting the mass occupancy of the heavy metal element in the first diffusion section 124 to 0.8 or less, it is guaranteed that the first diffusion section 124 has a stronger demagnetization resistance performance, and the manufacturing cost of the permanent magnet 120 is reduced, thereby satisfying the demand for low cost of permanent magnet motors and thereby improving the market competitiveness of the product.

[0043] 1, 2 and 3, in one embodiment of the present application, two permanent magnets 120 are defined as one set, and the rotor assembly 100 includes multiple sets of permanent magnets 120. In a first cross section, the two permanent magnets 120 of the same set are distributed in a V-shape.

[0044] In this embodiment, the arrangement of the permanent magnets 120 on the rotor assembly 100 is limited. For example, each rotor assembly 100 is provided with a plurality of sets of permanent magnets 120 arranged to surround the axis of the rotor core 110. Each set of permanent magnets 120 includes two permanent magnets 120 arranged symmetrically on both sides of a first plane. Here, the axis of the rotor core 110 and the diameter of the rotor core 110 are both within the first plane. Specifically, the rotor core 110 and the permanent magnets 120 are cut along a plane perpendicular to the axis of the rotor core 110, and the diameter of the rotor core 110 in this cross section becomes the first plane.

[0045] By installing multiple sets of permanent magnets 120 on the rotor assembly 100, the demagnetization resistance of the rotor assembly 100 can be enhanced, and the possibility of irreversible demagnetization occurring in the rotor assembly 100 can be further reduced. In addition, two of the permanent magnets 120 in each set are symmetrically distributed on both sides of the first plane, and multiple regions with strong demagnetization resistance can be formed on the axial side of the rotor core 110, making it easy to improve the demagnetization resistance of the entire rotor core 110. This achieves the technical effects of improving the reliability of the rotor assembly 100 and extending the service life of the rotor assembly 100.

[0046] In each set of permanent magnets 120, the two permanent magnets 120 are distributed in a V-shape on both sides of the first plane. For example, the permanent magnets 120 are cut by a plane perpendicular to the axis of the rotor core 110. In this cross section, an included angle of less than 90° exists between the two permanent magnets 120 located in the same set and the first plane, and the two permanent magnets 120 are formed to be distributed in a V-shape. Here, the openings of the two permanent magnets 120 distributed in a V-shape may face the axis of the rotor core 110 or may face the outside of the rotor core 110, but this is not forcibly limited in this embodiment.

[0047] By distributing the two permanent magnets 120 in the same set in a V-shape, a hybrid magnetic circuit structure can be formed in the rotor assembly 100. The hybrid magnetic circuit structure improves the steady-state and dynamic performance of the rotor assembly 100, contributes to improving the power density and overload capability of the permanent magnet motor, and the hybrid magnetic circuit is advantageous to achieve weak magnetic amplification. Meanwhile, it is advantageous to improve the coverage area of ​​the permanent magnets 120 in the circumferential direction of the rotor core 110, thus realizing the technical effect of improving the performance of the permanent magnet motor.

[0048] In any of the above embodiments, the two permanent magnets 120 in the same set are spaced apart.

[0049] In this embodiment, the two permanent magnets 120 in the same set are symmetrically distributed in a V-shape on both sides of the first plane, and a gap is placed between the two permanent magnets 120. By arranging the two permanent magnets 120 in the same set with a gap, the permanent magnets 120 can form multiple independent magnetic circuits, while optimizing the magnetic circuit distribution in the rotor assembly 100. Meanwhile, the gap between the two permanent magnets 120 can provide magnetic insulation to avoid interference between adjacent permanent magnets 120, and can improve the stability of the rotor assembly 100.

[0050] As shown in FIGS. 1, 2 and 3, in one embodiment of the present application, the permanent magnet 120 further includes a second diffusive portion 126 adjacent to the second end of the non-diffusive portion 122 .

[0051] In this embodiment, the permanent magnet 120 further includes a second diffusion portion 126. For example, the second diffusion portion 126 is located at a second end of the non-diffusion portion 122 close to the center line of the rotor core 110, and the second diffusion portion 126 and a part of the non-diffusion portion 122 are arranged in parallel in the first direction. By providing the second diffusion portion 126, two demagnetization resistance regions can be formed in the central region of the two permanent magnets 120 distributed in a V-shape, and the non-diffusion portion 122 is arranged between the first diffusion portion 124 and the second diffusion portion 126, thereby enhancing the demagnetization resistance performance of the permanent magnet 120.

[0052] For example, the mass occupancy of the heavy metal elements in the second diffusion part 126 is greater than that in the non-diffusion part 122, so that the coercive force of the two demagnetization-resistant regions in the middle part is greater than that of the non-diffusion parts on both sides. After the magnetic material is magnetized to saturation, when the external magnetic field returns to zero, its magnetic induction strength does not return to zero, and the magnetic induction strength cannot be returned to zero unless a magnetic field of a certain magnitude is applied in the opposite direction to the original magnetic field, and this magnetic field becomes the coercive force. As can be seen from this, the strength of the coercive magnetic field that the second diffusion part 126 can resist is greater than the strength of the coercive magnetic field that the non-diffusion part 122 can resist, so that when the non-diffusion part 122 is in danger of demagnetization, it can maintain its own magnetic induction strength, and thus prevent irreversible demagnetization from occurring in the non-diffusion part 122. The technical effects of improving the demagnetization resistance performance of the permanent magnet 120, extending the service life of the rotor assembly 100, and improving the reliability of the rotor assembly 100 are achieved.

[0053] In any of the above embodiments, the rotor assembly 100 further includes a second magnetic isolation bridge 140 located between and in contact with the two second diffusion portions 126 of the same set.

[0054] In this embodiment, the rotor assembly 100 further includes a second magnetic isolation bridge 140 disposed between two permanent magnets 120 of the same set, and both ends of the second magnetic isolation bridge 140 are in contact with the second diffusion parts 126 on the two permanent magnets 120 of the same set. By disposing the second magnetic isolation bridge 140 between the two second diffusion parts 126, the problem of magnetic flux leakage in the area between the two permanent magnets 120 of the same set can be avoided. Therefore, the disposing of the second magnetic isolation bridge 140 can effectively reduce the possibility of disturbance of the magnetic circuit and magnetic leakage problems in the rotor assembly 100. In addition, the technical effect of optimizing the structure of the rotor assembly 100 and improving the practicability and reliability of the rotor assembly 100 is achieved.

[0055] In any of the above embodiments, in the tangential direction of the rotor core 110, the minimum length of the second magnetic insulating bridge 140 is W2, and the length in the extension direction of the second diffusion part 126 is L2, where W2 1.2 × L2 = K2, 0.75 ≦ K2 ≦ 2.70.

[0056] In this embodiment, the dimensional relationship between the second magnetic insulating bridge 140 and the second diffusion part 126 is limited. For example, in the tangential direction of the rotor core 110, the minimum value of the length of the second magnetic insulating bridge 140 is W2, specifically, when the second magnetic insulating bridge 140 is filled in the gap between the adjacent end faces of two permanent magnets 120 of the same set, W2 is the minimum gap between the two permanent magnets 120. In addition, the length of the second diffusion part 126 in the extending direction of the permanent magnets 120 is L2, and W2 and L2 satisfy the following relationship: W2 1.2 × L2 = K2, 0.75 ≤ K2 ≤ 2.70.

[0057] By limiting the above dimensional relationship, it is possible to improve the local demagnetization resistance of the magnet while ensuring demagnetization reliability and without increasing the volume of the magnet, thereby improving the demagnetization resistance of the rotor assembly 100 and reducing the cost of the rotor assembly 100.

[0058] In any of the above embodiments, the mass occupancy of the heavy metal element in the second diffusion portion 126 is greater than the mass occupancy of the heavy metal element in the first diffusion portion 124 .

[0059] In this embodiment, the mass occupancy of the heavy metal elements in the second diffusion section 126 is greater than the mass occupancy of the heavy metal elements in the first diffusion section 124, i.e., the coercive force of the second diffusion section 126 is greater than the coercive force of the first diffusion section 124. By providing the first diffusion section 124 and the second diffusion section 126 with different mass occupancies of the heavy metal elements, it is possible to form first and second diffusion regions with different demagnetization resistance performances in each permanent magnet 120, and the demagnetization resistance performance of the rotor assembly 100 can be enhanced by the demagnetization resistance region with a gradient, thereby reducing the probability of the occurrence of the problem of irreversible demagnetization in the rotor assembly 100.

[0060] In any of the above embodiments, the mass occupancy rate of the heavy metal element in the second diffusion portion 126 is in the range of 0.4 to 0.75.

[0061] In this embodiment, the range of the mass occupancy of the heavy metal element in the second diffusion section 126 is limited. For example, the mass occupancy of the heavy metal element in the second diffusion section 126 needs to be 0.4 or more and 0.75 or less. By limiting the mass occupancy of the heavy metal element in the second diffusion section 126 to 0.4 or more, it is ensured that the second diffusion section 126 has a larger coercive force than the non-diffusion section 122, and it is ensured that the second diffusion section 126 can improve the demagnetization resistance performance of the entire permanent magnet 120. By limiting the mass occupancy of the heavy metal element in the second diffusion section 126 to 0.75 or less, it is ensured that the second diffusion section 126 has a stronger demagnetization resistance performance, and the manufacturing cost of the permanent magnet 120 can be reduced, the demand for cost reduction of permanent magnet motors can be met, and the market competitiveness of the product can be improved.

[0062] As shown in Figures 1, 2 and 3, in one embodiment of the present application, the first magnetic isolation bridge 130 is an air gap.

[0063] In this embodiment, the first magnetic insulating bridge 130 is an air gap, and the exemplary first magnetic insulating bridge 130 is machined and formed synchronously with the through-hole, and the gap between the permanent magnet 120 and the inner wall of the hole-shaped structure forms the above-mentioned first magnetic insulating bridge 130 and second magnetic insulating bridge 140. The second magnetic insulating bridge 140 is made of silicon steel, and specifically, can be integrally formed with the stator punching sheet made of silicon steel.

[0064] In either of the above embodiments, the permanent magnets 120 are radially magnetized, or the permanent magnets 120 are parallel magnetized.

[0065] In this embodiment, the magnetization direction of the permanent magnet 120 may be radially magnetized or parallelly magnetized. Accordingly, the magnetization directions of the multiple permanent magnets 120 on the rotor assembly 100 may be aligned to match the magnetization directions of the first diffusion portion 124, the second diffusion portion 126, and the non-diffusion portion 122 of each permanent magnet 120. When the non-diffusion portion 122 is demagnetized by an external magnetic field, the first diffusion portion 124 and the second diffusion portion 126, which have strong anti-demagnetization performance, can guarantee their own magnetism and magnetize the non-diffusion portion 122 by the first diffusion portion 124 and the second diffusion portion 126, thereby avoiding the problem of irreversible demagnetization of the permanent magnet 120.

[0066] In any of the above embodiments, in the first diffusion portion 124, the heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet 120.

[0067] In this embodiment, the heavy metal elements are uniformly distributed in the first diffusion portion 124 and the second diffusion portion 126 in the magnetization direction of the permanent magnet 120. By uniformly distributing the heavy metal elements in the diffusion portions in the magnetization direction, the uniformity of the distribution of the demagnetization resistant region on the permanent magnet 120 can be improved, and the probability that the permanent magnet 120 will experience irreversible demagnetization problems can be further reduced.

[0068] As shown in Figures 1, 2 and 3, in one embodiment of the present application, by cutting the permanent magnet 120 by a plane perpendicular to the rotor core 110, in the cross section, the area of ​​the first diffusion section 124 is S1, the area of ​​the permanent magnet 120 is S3, and the ratio of S1 to S3 is 0.1 or more and 0.4 or less.

[0069] In this embodiment, the dimensional relationship between the first diffusion section 124 and the non-diffusion section 122 is limited. For example, the permanent magnet 120 extends along the through hole parallel to the axis of the rotor core 110 in the through hole, and then, when the permanent magnet 120 is cut by a plane perpendicular to the axis of the rotor core 110, a cross section of the first diffusion section 124 and a cross section of the non-diffusion section 122 are obtained in the cross section, the area of ​​the cross section of the first diffusion section 124 is S1, and the area of ​​the cross section of the permanent magnet 120 is S3, where the ratio of S1 to S3 must be 0.1 or more and 0.4 or less, where the A direction in FIG. 3 is the width direction of the permanent magnet, and the B direction is the extension direction, i.e., the length direction, of the permanent magnet, and the area can be obtained by the product of the length and the width.

[0070] When the first diffusion portion 124 and the non-diffusion portion 122 are arranged in parallel along the first direction, the ratio of the cross-sectional area of ​​the first diffusion portion 124 to the cross-sectional area of ​​the permanent magnet 120 can reflect the relative dimensional relationship between the first diffusion portion 124 and the non-diffusion portion 122. By limiting the ratio of S1 to S3 to 0.1 or more, it is possible to avoid a situation in which the size of the first diffusion portion 124 is too small to provide effective anti-demagnetization support for the non-diffusion portion 122, and to ensure the anti-demagnetization performance of the entire permanent magnet 120. By limiting the ratio of S1 to S3 to 0.4 or less, it is possible to reduce the amount of heavy metal elements used in ensuring the anti-demagnetization performance of the permanent magnet 120, and to reduce the cost of the permanent magnet 120, thereby achieving both the anti-demagnetization requirements of the permanent magnet motor and the requirements for low cost. Furthermore, the structural arrangement of the permanent magnet 120 is optimized, the reliability of the permanent magnet 120 is improved, the life of the permanent magnet 120 is extended, and the technical effects of enhancing the market competitiveness of the product are realized.

[0071] In any of the above embodiments, by cutting the permanent magnet 120 by a plane perpendicular to the rotor core 110, in the cross section, the area of ​​the second diffusion section 126 is S2, the area of ​​the permanent magnet 120 is S3, and the ratio of S2 to S3 is greater than or equal to 0.1 and less than or equal to 0.4.

[0072] In this embodiment, the dimensional relationship between the second diffusion portion 126 and the non-diffusion portion 122 is limited. For example, the permanent magnet 120 extends along the through hole parallel to the axis of the rotor core 110 in the through hole, and then, when the permanent magnet 120 is cut by a plane perpendicular to the axis of the rotor core 110, a cross section of the permanent magnet 120 is obtained in the cross section, the cross section area of ​​the second diffusion portion 126 is S2, and the cross section area of ​​the permanent magnet 120 is S3, where the ratio of S2 to S3 must be 0.1 or more and 0.4 or less.

[0073] When the second diffusion portion 126 and the non-diffusion portion 122 are arranged in parallel along the first direction, the ratio of the cross-sectional area of ​​the second diffusion portion 126 to the cross-sectional area of ​​the permanent magnet 120 can reflect the relative dimensional relationship between the second diffusion portion 126 and the non-diffusion portion 122. By limiting the ratio of S2 to S3 to 0.1 or more, it is possible to avoid a situation in which the size of the second diffusion portion 126 is too small to provide effective anti-demagnetization support for the non-diffusion portion 122, and to ensure the anti-demagnetization performance of the entire permanent magnet 120. By limiting the ratio of S2 to S3 to 0.4 or less, it is possible to reduce the amount of heavy metal elements used in ensuring the anti-demagnetization performance of the permanent magnet 120, and to reduce the cost of the permanent magnet 120, thereby achieving both the anti-demagnetization requirements of the permanent magnet motor and the requirements for low cost. Furthermore, the structural arrangement of the permanent magnet 120 is optimized, the reliability of the permanent magnet 120 is improved, the life of the permanent magnet 120 is extended, and the technical effects of enhancing the market competitiveness of the product are realized.

[0074] In a second aspect of the present application, a permanent magnet motor is provided, which includes the rotor assembly 100 in any of the above embodiments.

[0075] In this embodiment, a permanent magnet motor is provided in which the rotor assembly 100 in any of the above embodiments is installed. Therefore, the permanent magnet motor has the advantages of the rotor assembly 100 in any of the above embodiments. It is possible to achieve technical effects that can be achieved by the rotor assembly 100 in any of the above embodiments. To avoid repetition, the details are omitted here.

[0076] In a third aspect of the present application, a compressor is provided, which includes the permanent magnet motor in the above embodiment.

[0077] In this embodiment, a compressor equipped with the permanent magnet motor in the above embodiment is proposed, and this compressor is applicable to an inverter air conditioner. Therefore, the compressor has the advantages of the permanent magnet motor in the above embodiment. It is possible to achieve the technical effects that can be achieved by the permanent magnet motor in the above embodiment. To avoid repetition, it is omitted here.

[0078] In the claims, specification and drawings of this application, the term "multiple" means two or more, but unless there is additional clear limitation, the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is merely for the purpose of more conveniently describing this application and facilitating the description process, and is not intended to indicate or imply that it must have a specific orientation, be configured and operated in a specific orientation, and therefore, these descriptions should not be understood as limiting this application. The terms "connected", "attached", "fixed", etc. should be understood in a broad sense, for example, "connected" may be a fixed connection between multiple objects, a detachable connection between multiple objects, or a direct connection between multiple objects that may be integrally connected, or an indirect connection between multiple objects via an intermediate medium. A person skilled in the art can understand the specific meaning of the above terms in this application from the above data.

[0079] In the claims, specification, and drawings of the present application, the reference to the term "one embodiment," "some embodiments," "specific embodiment," and the like means that the particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present application. In the claims, specification, and drawings of the present application, general language in the above terms does not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0080] The above is only a preferred embodiment of the present application, and does not limit the present application, and the present application may be modified or changed by those skilled in the art. Any amendments, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

[0081] The correspondence between the reference numerals and the names of the members in FIGS. 1 to 3 is as follows: [Explanation of symbols]

[0082] 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.

Claims

1. 1. A rotor assembly comprising: A rotor core having a through hole; a permanent magnet, the permanent magnet being provided within the through hole, a first cross section being obtained by cutting the permanent magnet along a plane perpendicular to an axis of the rotor core, and an included angle between an extension direction of the permanent magnet and a radial direction of the rotor core in the first cross section being greater than 0° and smaller than 90°; The permanent magnet is a non-diffusion portion including, in the extending direction, a first end adjacent to a circumferential side surface of the rotor core and a second end adjacent to an axis of the rotor core; a first diffusion portion that extends partially along a direction perpendicular to the extending direction and contacts a first end of the non-diffusion portion; a second diffusion portion extending along a direction perpendicular to the extending direction and in contact with a second end of the non-diffusion portion; a first magnetic insulating bridge in contact with the first diffusion portion and located between the first diffusion portion and a peripheral side surface of the rotor core, Here, the mass occupancy of heavy metal elements in the first diffusion portion and the second diffusion portion is greater than the mass occupancy of heavy metal elements in the non-diffusion portion.

2. a distance W1 between the first magnetic insulating bridge and a peripheral side surface of the rotor core in a radial direction of the rotor core; The length of the first diffusion portion in the extending direction is L1, Here, W1 １．３ 2. The rotor assembly of claim 1, wherein L1 x K1, 0.04≦K1≦0.57, said K1 being a first dimensional ratio.

3. The rotor assembly according to claim 1 , wherein a mass occupancy rate of the heavy metal elements in the first diffusion portion is in the range of 0.6 to 0.

8.

4. Two of the permanent magnets form a pair, and the rotor assembly includes a plurality of pairs of permanent magnets; The rotor assembly according to claim 1 , wherein in the first cross section, two of the permanent magnets of the same set are distributed in a V-shape.

5. The rotor assembly according to claim 4 , wherein two of said permanent magnets in the same set are spaced apart.

6. 2. The rotor assembly of claim 1, further comprising a second magnetic isolation bridge located between and in contact with two of the second diffusion portions of the same set.

7. In a tangential direction of the rotor core, the minimum value of the length of the second magnetic insulating bridge is W2, The second diffusion portion has a length L2 in the extending direction, Here, W2 １．２ 7. The rotor assembly of claim 6, wherein L2=K2, 0.75≦K2≦2.70, said K2 being a second dimensional ratio.

8. The rotor assembly according to claim 7 , wherein a mass occupancy rate of the heavy metal elements in the second diffusion portion is greater than a mass occupancy rate of the heavy metal elements in the first diffusion portion.

9. The rotor assembly according to claim 8 , wherein the mass occupancy rate of the heavy metal elements in the second diffusion portion is in the range of 0.4 to 0.

75.

10. The rotor assembly of claim 6 , wherein said first magnetic isolation bridge and said second magnetic isolation bridge are air gaps.

11. The rotor assembly of claim 1 , wherein the permanent magnets are radially magnetized or the permanent magnets are parallel magnetized.

12. The rotor assembly according to claim 11 , wherein in the first diffusion portion, the heavy metal elements are uniformly distributed in the magnetization direction of the permanent magnet.

13. A permanent magnet motor comprising a rotor assembly according to any one of claims 1 to 12.

14. A compressor comprising a permanent magnet motor as described in claim 13.

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