Rotor assembly, permanent magnet auxiliary synchronous reluctance motor and new energy vehicle

Abstract

The application provides a rotor assembly, a permanent magnet auxiliary synchronous reluctance motor and a new energy vehicle. The rotor assembly comprises a rotor core, at least two magnetic steel grooves are arranged on the rotor core, and magnetic steels are arranged in the magnetic steel grooves. The two magnetic steel grooves form an included angle in the direction extending to the center of the rotor core, so that the interval of one end of the two magnetic steel grooves close to the center of the rotor core is smaller than the interval of the other end. A limiting piece is arranged on the first side wall of one magnetic steel groove, the magnetic steel is tightly attached to the first side wall through the limiting piece, and the first side wall is the side wall away from the other magnetic steel groove. The limiting piece is arranged on the side wall away from the other magnetic steel groove in the two magnetic steel grooves arranged at an included angle, so that the centrifugal force generated by the magnetic steel only acts on the side wall, the maximum stress of the magnetic separation bridge between the two magnetic steel grooves is reduced, and the reliability of the rotor during high-speed operation is ensured.

Description

Technical Field

[0001] This application belongs to the field of new energy vehicle technology, specifically relating to a rotor assembly, a permanent magnet assisted synchronous reluctance motor, and a new energy vehicle. Background Technology

[0002] With increasing emphasis on environmental protection and efficient energy utilization, the electrification of automobiles has become an industry consensus. Currently, the main research directions for electric motor drive systems in new energy vehicles are: improving the efficiency, power density, safety, and reliability of these systems. Permanent magnet assisted synchronous reluctance motors are widely used in pure electric or hybrid new energy vehicles due to their advantages such as high torque density, high efficiency, good steady-state performance, and high reliability.

[0003] The rotor of a permanent magnet assisted synchronous reluctance motor typically employs a multi-layered magnetic barrier structure to achieve high reluctance torque. Magnetic isolation bridges are placed between adjacent magnetic barrier structures to maintain the mechanical strength of the motor during operation. However, since the width of the magnetic isolation bridges is usually small, the mechanical strength of the rotor is one of the design and manufacturing challenges. When the motor operates at high speed, the effect of centrifugal force is particularly prominent, far exceeding the influence of other forces. Furthermore, the magnitude of the centrifugal force is directly proportional to the square of the rotational speed. As the rotational speed increases, the centrifugal force increases significantly, easily leading to excessive stress on the magnetic isolation bridges and causing rotor damage. Summary of the Invention

[0004] Therefore, this application provides a rotor assembly, a permanent magnet assisted synchronous reluctance motor, and a new energy vehicle, which can solve the problem of rotor damage caused by excessive stress in the magnetic bridge in the prior art.

[0005] To address the aforementioned problems, this application provides a rotor assembly, comprising:

[0006] The rotor core has at least two magnetic slots, and each magnetic slot contains a magnet; the two magnetic slots form an angle in the direction extending toward the center of the rotor core, such that the distance between the two magnetic slots at one end near the center of the rotor core is smaller than the distance at the other end.

[0007] A limiting member is provided on the first sidewall of one of the magnetic steel grooves, and the magnet is tightly attached to the first sidewall via the limiting member; the first sidewall is the sidewall away from the other magnetic steel groove.

[0008] Optionally, the two magnetic slots are designated as a first magnetic slot and a second magnetic slot. The rotor assembly also includes a third magnetic slot, the extension direction of which is perpendicular to the radial direction of the rotor core, and it is located between the ends of the first magnetic slot and the second magnetic slot near the center of the rotor core.

[0009] Optionally, the first magnet slot, the third magnet slot, and the second magnet slot form a U-shape, and the rotor assembly further includes a fourth magnet slot and a fifth magnet slot disposed within the U-shape. The fourth magnet slot and the fifth magnet slot are arranged intersectingly in the direction extending toward the center of the rotor core. The distance between the end of the fourth magnet slot and the fifth magnet slot closest to the center of the rotor core is smaller than the distance between the other end.

[0010] Optionally, the limiting member includes two shoulders, each shoulder being a protrusion extending into the magnet groove, and the magnet being confined between the two shoulders.

[0011] Optionally, the end of the protrusion away from the first sidewall has a bend along the circumference of the rotor core, the bend facing the side where the magnet is located, and a portion of the magnet is located between the bend and the first sidewall.

[0012] Optionally, the magnet is stepped along the circumference of the rotor core, and the length of the side of the magnet closest to the first sidewall along the radial direction of the rotor core is greater than the length of the opposite sidewall; the bend is in contact with the stepped surface of the magnet.

[0013] Optionally, the length of the magnet on the side closest to the first sidewall along the radial direction of the rotor core is set as L1, and the length of the opposite sidewall is set as L2, satisfying L2 / L1 = 94%-95%.

[0014] Optionally, along the circumference of the rotor core, the sidewall opposite to the first sidewall is designated as the second sidewall, and the magnet and the second sidewall are spaced apart.

[0015] Optionally, the gap between the magnet and the second sidewall is set to 0.05-0.15 mm.

[0016] Optionally, one of the two shoulders that is far from the center of the rotor core is designated as the first shoulder, and the other is designated as the second shoulder; along the radial direction of the rotor core, the width of the first shoulder is designated as L3, and the width of the second shoulder is designated as L4, satisfying L3 / L4 = 1-2.

[0017] According to another aspect of this application, a permanent magnet assisted synchronous reluctance motor is provided, including the rotor assembly as described above.

[0018] According to another aspect of this application, a new energy vehicle is provided, including the rotor assembly as described above or the permanent magnet assisted synchronous reluctance motor as described above.

[0019] This application provides a rotor assembly, comprising: a rotor core having at least two magnetic slots, wherein a magnet is disposed in each magnetic slot; the two magnetic slots forming an angle in a direction extending toward the center of the rotor core, such that the distance between the two magnetic slots at one end near the center of the rotor core is less than the distance between the other ends; a limiting member is provided on a first sidewall of one of the magnetic slots, and the magnet is tightly attached to the first sidewall via the limiting member; the first sidewall is the sidewall away from the other magnetic slot.

[0020] In this application, a limiting member is provided on the far side wall of two magnetic steel slots arranged at an angle, so that the centrifugal force generated by the magnets only acts on that side wall, thereby reducing the maximum stress of the magnetic isolation bridge between the two magnetic steel slots and ensuring the reliability of the rotor when it is running at high speed. Attached Figure Description

[0021] To more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0022] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0023] Figure 1 This is a partial structural schematic diagram of the rotor according to an embodiment of this application;

[0024] Figure 2 This is a partial structural schematic diagram of the rotor core according to an embodiment of this application;

[0025] Figure 3 This is a partial structural schematic diagram of the rotor according to an embodiment of this application;

[0026] Figure 4 This is a partial structural schematic diagram of the rotor core according to an embodiment of this application;

[0027] Figure 5 This is a schematic diagram of the structure of the first magnet in an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of the cooperation structure between the first shoulder and the magnet in an embodiment of this application;

[0029] Figure 7 This is a schematic diagram of the cooperation structure between the second shoulder and the magnet in an embodiment of this application;

[0030] Figure 8 The simulation diagram of rotor core stress in the traditional scheme;

[0031] Figure 9 This is a simulation diagram of rotor core stress in an embodiment of this application.

[0032] The reference numerals in the attached figures are as follows:

[0033] 1. Rotor core;

[0034] 2. Magnetic steel channel; 21. First magnetic steel channel; 211. First sidewall; 212. Second sidewall; 22. Second magnetic steel channel; 23. Fourth magnetic steel channel; 24. Fifth magnetic steel channel; 25. Third magnetic steel channel;

[0035] 3. Magnet; 31. First magnet; 311. First side of first magnet; 312. Second side of first magnet; 313. Third side of first magnet; 314. Fourth side of first magnet; 32. Second magnet; 33. Fourth magnet; 34. Fifth magnet; 35. Third magnet;

[0036] 41. First shoulder; 411. First shoulder, first side; 412. First shoulder, second side; 413. First shoulder, third side; 414. First shoulder, fourth side; 415. First shoulder, fifth side;

[0037] 42. Second shoulder; 421. First side of second shoulder; 422. Second side of second shoulder; 423. Third side of second shoulder; 424. Fourth side of second shoulder; 425. Fifth side of second shoulder;

[0038] O, the center of the rotor core;

[0039] I. Centerline of part of the rotor core. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0043] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0044] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0045] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0046] See also Figure 1 As shown in the figure, according to an embodiment of this application, a rotor assembly includes:

[0047] The rotor core 1 is provided with at least two magnetic slots 2, and a magnet 3 is provided in the magnetic slots 2; the two magnetic slots 2 form an angle in the direction extending toward the center of the rotor core 1, so that the distance between the two magnetic slots 2 at one end near the center O of the rotor core is smaller than the distance at the other end.

[0048] A limiting member is provided on the first side wall 211 of one of the magnetic steel grooves 2, and the magnet 3 is closely attached to the first side wall 211 through the limiting member; the first side wall 211 is the side wall away from the other magnetic steel groove 2.

[0049] In this application, a limiting member is provided on the far side wall of the two magnetic steel slots 2 arranged at an angle, so that the centrifugal force generated by the magnet 3 only acts on the side wall, thereby reducing the maximum stress of the magnetic isolation bridge between the two magnetic steel slots 2 and ensuring the reliability of the rotor when it is running at high speed.

[0050] In the traditional structure, the two magnet slots 2 are set at an angle, and the magnet slots 2 are inclined relative to the center line I of the rotor core 1. The magnet 3 is directly assembled in the magnet slots 2. Due to the centrifugal force generated by the high-speed rotating magnet 3, it will directly act on the side wall near the center line I of the rotor core 1, i.e., the second side wall 212, thereby causing a large stress on the magnetic bridge between the two magnet slots 2.

[0051] This application provides a limiting member on the first sidewall 211 away from the other magnet slot 2. The magnet 3 is tightly attached to the first sidewall 211 through the limiting member. In this way, when rotating at high speed, the centrifugal force generated by the magnet 3 will act directly on the first sidewall 211 through the limiting member, reducing the force on the second sidewall 212, or even having no force on the second sidewall 212. As a result, the stress of the magnetic bridge between the two magnet slots 2 will be greatly reduced, effectively improving the mechanical strength of the rotor core 1 and ensuring the reliability of the rotor when rotating at high speed.

[0052] When the magnet slots 2 are set to be two adjacent ones, they form a V-shaped structure with the V-shaped opening facing the outer periphery of the rotor core 1. The limiting member is set on the farthest side wall of the two magnet slots 2 along the circumference of the rotor core 1. In this way, the centrifugal force generated by the high-speed rotating magnet 3 has a reduced impact on the magnetic bridge between the two magnet slots 2.

[0053] In some embodiments, the two magnetic slots 2 are designated as a first magnetic slot 21 and a second magnetic slot 22. The rotor assembly further includes a third magnetic slot 25, the extension direction of which is perpendicular to the radial direction of the rotor core 1, and it is located between the first magnetic slot 21 and the second magnetic slot 22 at one end near the center O of the rotor core.

[0054] For the U-shaped structure formed by the first magnet slot 21, the third magnet slot 25, and the second magnet slot 22, the limiting member is located in the first magnet slot 21 and the second magnet slot 22 on both sides of the U-shape, and on the farthest side wall along the circumference of the rotor core. In this way, the stress on the magnetic isolation bridge between the first magnet slot 21 and the third magnet slot 25, and between the third magnet slot 25 and the second magnet slot 22, will be greatly reduced, thereby ensuring the reliability of the motor operation.

[0055] In some embodiments, the first magnet slot 21, the third magnet slot 25, and the second magnet slot 22 form a U-shape. The rotor assembly further includes a fourth magnet slot 23 and a fifth magnet slot 24 disposed within the U-shape. The fourth magnet slot 23 and the fifth magnet slot 24 are intersecting in the direction extending toward the center of the rotor core 1. The distance between the end of the fourth magnet slot 23 and the fifth magnet slot 24 closest to the center O of the rotor core is smaller than the distance between the other ends.

[0056] For a V-shaped structure consisting of a fourth magnet 23 and a fifth magnet 24, which is set within the U-shaped structure formed by the first magnet 21, the third magnet 25, and the second magnet 22, since the fourth magnet 23 and the fifth magnet 24 are entirely within the U-shaped structure, there is no need to add limiting components to the fourth magnet 23 and the fifth magnet 24.

[0057] In some embodiments, the limiting member includes two shoulders, which are protrusions extending into the magnet groove 2, and the magnet 3 is constrained between the two shoulders.

[0058] The limiting component uses two shoulders that clamp the magnets 3. The shoulders are protrusions that extend into the magnet groove 2. The structure is simple and easy to manufacture.

[0059] The ferrite magnets 3 used in traditional permanent magnet assisted synchronous reluctance motors are prone to irreversible demagnetization, specifically at the edges of both ends of the magnets 3, which reduces the motor's output capacity. In this application, shoulders are provided at both ends of the magnets 3. These shoulders help to clear the magnetic circuit, protect the edges of the magnets 3 from irreversible demagnetization, and improve the motor's resistance to demagnetization.

[0060] In some embodiments, the end of the protrusion away from the first sidewall 211 is provided with a bend along the circumference of the rotor core 1, the bend facing the side where the magnet 3 is located, and a portion of the magnet 3 is disposed between the bend and the first sidewall 211.

[0061] A bend is provided on the end of the protrusion away from the first side wall 211, which is circumferentially bent to form a latch on the magnet 3. This allows the centrifugal force generated by the high-speed rotating magnet 3 to act on the first side wall 211 through the limiting member, thereby reducing the stress on the magnetic bridge.

[0062] In actual assembly, the magnet 3 can be directly inserted along the rotor axis in the area enclosed by the two protrusions, bends and the first side wall 211, which is simple to operate.

[0063] In some embodiments, the magnet 3 is stepped along the circumference of the rotor core 1, and the length of the side of the magnet 3 closest to the first sidewall 211 along the radial direction of the rotor core 1 is greater than the length of the opposite side; the bend is in contact with the stepped surface of the magnet 3.

[0064] With the bent shoulder, the magnet 3 is set in a stepped shape and fits in close to the bent surface, so that part of the magnet 3 is exposed from the gap between the two opposite bends, the two protrusions and the area enclosed by the bend and the first side wall 211, and close to the second side wall 212, to ensure the magnetic circuit in the rotor and reduce magnetic loss.

[0065] In some embodiments, the length of the side of the magnet 3 closest to the first sidewall 211 along the radial direction of the rotor core 1 is set as L1, and the length of the opposite side is set as L2, satisfying L2 / L1 = 94%-95%.

[0066] The magnet 3 is specifically convex in shape, with shoulders on both sides fitting snugly against the bend. The upper and lower dimensions of this convex shape are defined as L2 and L1, respectively, satisfying the constraint relationship L2 / L1 = 94%-95%. This constraint aims to increase the area of ​​magnet 3 while meeting strength requirements, thereby increasing the motor's output torque. A larger L2 (i.e., a smaller difference between L1 and L2) results in a larger magnet 3 area and greater motor output torque. However, a larger L2 also reduces the contact area between magnet 3 and the shoulders. During high-speed rotor rotation, stress concentration occurs at this contact surface, significantly increasing stress, reducing rotor mechanical strength, and potentially damaging magnet 3 and the shoulders. The purpose of this constraint relationship is to ensure the strength of magnet 3 and the shoulders while maximizing the area of ​​magnet 3.

[0067] In some embodiments, along the circumference of the rotor core 1, the sidewall opposite the first sidewall 211 is designated as a second sidewall 212, and the magnet 3 and the second sidewall 212 are spaced apart. Preferably, the gap between the magnet 3 and the second sidewall 212 is 0.05-0.15 mm.

[0068] The gap between the magnet 3 and the second sidewall 212 reduces the stress on the magnetic isolation bridge between the first magnet slot 21 and the third magnet slot 25 and the second magnet slot 22 in the U-shaped structure formed by the first magnet slot 21, the third magnet slot 25 and the second magnet slot 22, thereby improving the mechanical strength of the rotor core 1.

[0069] The purpose of this gap is to prevent the centrifugal force on the magnet 3 from acting on the second sidewall 212. This reduces the stress on the two magnetic isolation bridges near the rotor center. The minimum value of 0.05mm is taken into account the deformation of the rotor at high speed (approximately 0.02mm) and the manufacturing process. The gap should not be too large, as this will lead to a decrease in the motor's output torque. For example, a gap of 0.1mm results in an average output torque of 270Nm, while a gap of 0.25mm results in an average output torque of 260Nm.

[0070] In some embodiments, one of the two shoulders that is far from the center O of the rotor core is designated as the first shoulder 41 and the other as the second shoulder 42; in the radial direction along the rotor core 1, the width of the first shoulder 41 is designated as L3 and the width of the second shoulder 42 is designated as L4, satisfying L3 / L4=1-2.

[0071] When the rotor is running at high speed, the magnet 3 will be subjected to a large centrifugal force, which will cause the first shoulder 41 to be subjected to greater stress than the second shoulder 42. Therefore, L3 and L4 have a constraint relationship: L3 = (1-2)L4. This constraint relationship can make the stress on the shoulder more consistent, avoid excessive local stress in the rotor core 1, and reduce the mechanical strength of the rotor.

[0072] According to another aspect of this application, a permanent magnet assisted synchronous reluctance motor is provided, including the rotor assembly as described above.

[0073] When a permanent magnet assisted synchronous reluctance motor operates at high speed, the rotor rotates at high speed, and the rotor core 1 and magnets 3 are subjected to significant centrifugal force. The maximum stress point of the rotor core 1 often appears on the magnetic isolation bridge between the first magnet slot 21, the third magnet slot 25, and the second magnet slot 22. Shoulders are provided on both sides of the first sidewall 211 of the first magnet 3 and / or the second magnet slot 22. This allows the centrifugal force acting on the magnets 3 in the first magnet 3 and / or the second magnet slot 22 to act on the shoulders, reducing the stress on the magnetic isolation bridge, lowering the maximum stress value of the rotor, effectively improving the rotor's mechanical strength, and ensuring the rotor's reliability during high-speed rotation. Furthermore, the edges of the magnets 3 are more prone to demagnetization. The aforementioned shoulders, located on both sides of the magnets 3, can help to clear the magnetic circuit, protect the edges of the magnets 3 from irreversible demagnetization, and improve the motor's resistance to demagnetization.

[0074] According to another aspect of this application, a new energy vehicle is provided, including the rotor assembly as described above or the permanent magnet assisted synchronous reluctance motor as described above.

[0075] The aforementioned rotor assembly or permanent magnet assisted synchronous reluctance motor is used in new energy vehicles, specifically as a motor for 3-4.5t logistics vehicles. The motor stator has an outer diameter of 230mm, a peak power of 70kW-80kW, a peak torque of 200Nm-300Nm, and a peak speed of 9000rpm-12000rpm.

[0076] In the specific rotor structure configuration, the magnet slots 2 on the rotor include a first magnet slot 21, a second magnet slot 22, a third magnet slot 25, a fourth magnet slot 23, and a fifth magnet slot 24; correspondingly, the magnets 3 include a first magnet 31, a second magnet 32, a third magnet 35, a fourth magnet 33, and a fifth magnet 34; the first magnet 31, the second magnet 32, the third magnet 35, the fourth magnet 33, and the fifth magnet 34 are respectively installed in the first magnet slot 21, the second magnet slot 22, the third magnet slot 25, the fourth magnet slot 23, and the fifth magnet slot 24.

[0077] The first magnet groove 21, the second magnet groove 22, and the third magnet groove 25 constitute the first layer, and the fourth magnet groove 23 and the fifth magnet groove 24 constitute the second layer, presenting a "UV" structure, such as... Figure 1-4 As shown, in the first magnet groove 21 and the second magnet groove 22, there are shoulders on both sides of the sidewalls that are far apart from each other. The shoulder closer to the outer edge of the rotor is the first shoulder 41, and the shoulder closer to the center of the rotor is the second shoulder 42.

[0078] like Figure 4 As shown, the long side of the first magnet slot 21 furthest from the center line I of the rotor core is the first sidewall 211, and the long side closest to the center line I is the second sidewall 212. The lower edge of the first magnet 31 is the first side 311, and the upper edge is the second side 312. The length of the first side 311 is L1, and the length of the second side 312 is L2. The upper edge of the first magnet is longer than the lower edge. The first magnet 21 has a "convex" shape. There is a constraint relationship between L1 and L2: L1-L2 = (5%-6%)*L1, preferably L1-L2 = 5.66%*L1.

[0079] The first shoulder 41 is formed by the first shoulder first side 411, the first shoulder second side 412, the first shoulder third side 413, the first shoulder fourth side 414, and the first shoulder fifth side 415, wherein the first shoulder fourth side 414 and the first shoulder fifth side 415 are connected by an arc transition, the radius of which is 0.5mm-1.5mm, preferably 1mm; the second shoulder 42 is formed by the second shoulder first side 421, the second shoulder second side 422, the second shoulder third side 423, the second shoulder fourth side 424, and the second shoulder fifth side 425, wherein the second shoulder fourth side 424 and the second shoulder fifth side 425 are connected by an arc transition, the radius of which is 0.5mm-1.5mm, preferably 0.8mm.

[0080] The first magnet 31 is installed in the first magnet slot 21. The first side 311 of the first magnet is in contact with the first sidewall 211, the third side 313 of the first magnet is in contact with the second side 412 of the first shoulder, and the fourth side 314 of the first magnet is in contact with the second side 422 of the second shoulder. There is a gap of 0.05-0.15mm, preferably 0.1mm, between the second side 312 of the first magnet and the second sidewall 212. This gap reduces the stress on the magnetic isolation bridge between the first magnet slot 21 and the fifth magnet slot, as well as the magnetic isolation bridge between the first magnet slot 22 and the fifth magnet slot, thereby improving the mechanical strength of the rotor core. In addition, this gap improves the rotor's resistance to demagnetization, ensuring that the motor can operate for a long time.

[0081] Similarly, the two shoulder structures described above can be installed in the second magnet groove 22.

[0082] The distance between the first side 411 and the fifth side 415 of the first shoulder is the radial thickness L3 of the first shoulder, and the distance between the first side 421 and the fifth side 425 of the second shoulder is the radial thickness L4 of the second shoulder. When the rotor is running at high speed, the magnets will be subjected to a large centrifugal force, resulting in the first shoulder 41 being subjected to greater stress than the second shoulder 42. Therefore, L3 and L4 have a constraint relationship: L3 = (1-2) * L4, and the value of L3 is in the range of 1.5mm-2mm, preferably L3 = 1.8mm. This constraint relationship can make the stress on the shoulders more uniform, avoiding excessive local stress in the rotor core and reducing the mechanical strength of the rotor. The length of the first side of the first shoulder is 2mm-3mm, preferably 2.45mm, and the length of the third side of the first shoulder is 1mm-1.2mm, preferably 1mm. The length of the first side of the second shoulder is 2mm-3mm, preferably 2.45mm, and the length of the third side of the second shoulder is 1mm-1.2mm, preferably 1mm.

[0083] This application reduces the maximum stress on the magnetic bridge by designing the magnetic slot shoulder on the rotor core and the matching magnet, thereby solving the mechanical strength problem of the rotor of the permanent magnet assisted synchronous reluctance motor under high-speed conditions and the problem of local demagnetization of the magnet.

[0084] It will be readily understood by those skilled in the art that the above embodiments can be freely combined and superimposed without conflict.

[0085] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above description is merely a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A rotor assembly, characterized in that, include: The rotor core (1) is provided with at least two magnetic slots (2), and a magnet (3) is provided in the magnetic slots (2); the two magnetic slots (2) form an angle in the direction extending toward the center of the rotor core (1), so that the distance between the two magnetic slots (2) at one end near the center (O) of the rotor core is smaller than the distance at the other end; A limiting member is provided on the first sidewall (211) of one of the magnet slots (2), and the magnet (3) is tightly attached to the first sidewall (211) via the limiting member; the first sidewall (211) is the sidewall away from the other magnet slot (2). The two magnetic slots (2) are designated as a first magnetic slot (21) and a second magnetic slot (22). The rotor assembly also includes a third magnetic slot (25). The extension direction of the third magnetic slot (25) is perpendicular to the radial direction of the rotor core (1), and it is located between the first magnetic slot (21) and the second magnetic slot (22) at one end near the center (O) of the rotor core. The first magnet slot (21), the third magnet slot (25) and the second magnet slot (22) form a U-shape. The rotor assembly also includes a fourth magnet slot (23) and a fifth magnet slot (24) disposed within the U-shape. The fourth magnet slot (23) and the fifth magnet slot (24) are arranged intersectingly in the direction extending toward the center of the rotor core (1). The distance between the fourth magnet slot (23) and the fifth magnet slot (24) at one end near the center (O) of the rotor core is smaller than the distance at the other end.

2. The rotor assembly according to claim 1, characterized in that, The limiting member includes two shoulders, which are protrusions extending into the magnet groove (2), and the magnet (3) is constrained between the two shoulders.

3. The rotor assembly according to claim 2, characterized in that, The protrusion is provided with a bend along the circumference of the rotor core (1) at one end away from the first sidewall (211), the bend is toward the side where the magnet (3) is located, and part of the magnet (3) is located between the bend and the first sidewall (211).

4. The rotor assembly according to claim 3, characterized in that, The magnet (3) is stepped along the circumference of the rotor core (1), and the length of the side of the magnet (3) close to the first sidewall (211) along the radial direction of the rotor core (1) is greater than the length of the opposite side; the bend is in contact with the stepped surface of the magnet (3).

5. The rotor assembly according to claim 4, characterized in that, The length of the magnet (3) along the radial direction of the rotor core (1) is set as L1 on the side closest to the first sidewall (211), and the length of the opposite side is set as L2, satisfying L2 / L1=94%-95%.

6. The rotor assembly according to any one of claims 2-5, characterized in that, Along the circumference of the rotor core (1), the side wall opposite to the first side wall (211) is set as the second side wall (212), and the magnet (3) and the second side wall (212) are set at intervals.

7. The rotor assembly according to claim 6, characterized in that, The gap between the magnet (3) and the second sidewall (212) is set to 0.05-0.15mm.

8. The rotor assembly according to claim 2, characterized in that, Of the two shoulders, the one furthest from the center (O) of the rotor core is designated as the first shoulder (41), and the other is designated as the second shoulder (42). In the radial direction along the rotor core (1), the width of the first shoulder (41) is designated as L3, and the width of the second shoulder (42) is designated as L4, satisfying L3 / L4=1-2.

9. A permanent magnet assisted synchronous reluctance motor, characterized in that, Includes the rotor assembly as described in any one of claims 1-8.

10. A new energy vehicle, characterized in that, Includes the rotor assembly as described in any one of claims 1-8 or the permanent magnet assisted synchronous reluctance motor as described in claim 9.

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