Rotor assembly with sheath and radial flux permanent magnet motor with rotor assembly

Abstract

The rotor assembly with the sheath comprises a shaft, a balancing ring, a permanent magnet and the sheath, the balancing ring is in interference fit with the shaft, the radial end face of the balancing ring is in contact with the radial end face of the permanent magnet, and the inner surface of the sheath is connected with the outer surface of the permanent magnet; the permanent magnet and the sheath are both of an axial segmented structure, and the segmented interface of the permanent magnet and the segmented interface of the sheath are arranged in a staggered mode. Compared with the prior art, the motor has the advantages of shortening the axial length of the permanent magnet, reducing the temperature rise of the motor and the like.

Description

Technical Field

[0001] The utility model relates to a permanent magnet motor, in particular to a rotor assembly with a sleeve and a radial flux permanent magnet motor having the rotor assembly. Background Art

[0002] Permanent magnet motors have the advantages of high power density and high torque, and are widely used in various fields.

[0003] In the field of high-speed permanent magnet motors, the surface-mounted rotor has a simple structure and is easy to assemble, but this structure will generate huge centrifugal force when rotating at high speeds. At the same time, the tensile strength and fracture toughness of the permanent magnet are relatively low, and the integrity of the permanent magnet during high-speed rotation cannot be guaranteed.

[0004] In addition, the axial length of the radial flux permanent magnet motor is relatively long, that is, it requires a longer permanent magnet. When the motor is running, the eddy current loss in the longer permanent magnet causes the rotor temperature to rise, which may cause the permanent magnet to demagnetize and affect the normal operation of the motor. The axial segmented permanent magnet can significantly reduce the eddy current loss of the permanent magnet without affecting the output torque capacity of the motor.

[0005] After searching, Chinese patent publication number CN116961272A provides a hollow cup motor with an integrated sleeve magnet. The sleeve is a cylindrical structure with a cavity, and the cylindrical wall thickness is 0.05mm-2mm. Usually, the ratio of the outer diameter of the rotor to the rotor shaft length is greater than the ratio of the outer diameter of the hollow cup motor to the motor shaft length, that is, the cylindrical structure is too slender and thin-walled. Therefore, the processing cost of this structure is high or even impossible to process.

[0006] At the same time, Chinese patent publication number CN117578765A discloses a permanent magnet motor rotor consisting of a shaft core, a protective sleeve and a permanent magnet. Since the compressive strength of the permanent magnet is relatively low, the interference fit between the protective sleeve and the permanent magnet may cause cracks or even breakage in the permanent magnet. In addition, the processing of the polygonal core shaft is extremely difficult and the cost is extremely high, which is not conducive to mass production.

[0007] Therefore, how to shorten the axial length of the permanent magnet and reduce the temperature rise of the motor when the radial cross-section of the permanent magnet is small becomes a technical problem that needs to be solved. Utility Model Content

[0008] The purpose of the utility model is to provide a rotor assembly with a sleeve and a radial flux permanent magnet motor having the rotor assembly in order to overcome the defects of the prior art.

[0009] The purpose of the utility model can be achieved through the following technical solutions:

[0010] According to one aspect of the utility model, a rotor assembly with a sleeve is provided, comprising a shaft, a balancing ring, a permanent magnet and a sleeve, wherein the balancing ring is interference fit with the shaft, the radial end face of the balancing ring is in contact with the radial end face of the permanent magnet, and the inner surface of the sleeve is connected to the outer surface of the permanent magnet; the permanent magnet and the sleeve are both axially segmented structures, and the segmented interface of the permanent magnet is staggered with the segmented interface of the sleeve.

[0011] As a preferred technical solution, the permanent magnet includes a plurality of segmented cylindrical permanent magnet units, and the plurality of segmented cylindrical permanent magnet units are arranged along the axial direction of the shaft.

[0012] As a preferred technical solution, the multiple segments of the segmented cylindrical permanent magnet units are structures of equal length.

[0013] As a preferred technical solution, each of the segmented cylindrical permanent magnet units includes a plurality of permanent magnet blocks respectively bonded to the outer surface of the shaft.

[0014] As a preferred technical solution, the inner surface and outer surface of the permanent magnet block are concentric arcs.

[0015] As a preferred technical solution, the permanent magnet block is specifically: (axial length of the permanent magnet block / radial thickness of the permanent magnet block)≤180.

[0016] As a preferred technical solution, the sleeve includes multiple segmented sleeves arranged along the axial direction of the shaft, the inner surface of which is bonded to the outer surface of the permanent magnet block by glue, and the second axial interface of the segmented sleeve and the first axial interface of the segmented cylindrical permanent magnet unit are not in the same radial plane.

[0017] As a preferred technical solution, the segmented sheath is specifically: (sheath axial length / sheath radial wall thickness)≤180.

[0018] As a preferred technical solution, the shaft is a cylindrical structure.

[0019] According to another aspect of the utility model, a radial flux permanent magnet motor having a rotor assembly is provided, comprising a stator assembly and a housing assembly, wherein the motor further comprises the rotor assembly.

[0020] Compared with the prior art, the utility model has the following advantages:

[0021] 1) The permanent magnet and the sleeve of the utility model are both axially segmented structures, wherein the segmented interface of the permanent magnet and the segmented interface of the sleeve are staggered, which is conducive to controlling the concentricity of the rotor. The sleeve and the permanent magnet of the utility model are bonded together, eliminating the risk of permanent magnet fracturing caused by interference fit between the permanent magnet and the sleeve;

[0022] 2) When the radial cross-section of the permanent magnet is small, the utility model shortens the axial length of the permanent magnet, which helps to improve the qualified rate of permanent magnet products and reduce costs;

[0023] 3) The rotor assembly of the utility model adopts an axial multi-segment permanent magnet structure, which helps to reduce the temperature rise of the motor without affecting the output torque capacity of the motor;

[0024] 4) The utility model shortens the length of the sheath, improves the feasibility of sheath processing, and reduces costs;

[0025] 5) The utility model staggers the axial interface of the segmented sleeve and the axial interface of the segmented cylindrical permanent magnet, which helps to improve the runout of the rotor assembly and reduce the risk of friction between the rotor assembly and the stator assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the rotor assembly of the utility model;

[0027] Figure 2 for Figure 1 A schematic diagram of the enlarged structure of part A;

[0028] Figure 3 This is a radial cross-sectional view of the rotor assembly of the utility model;

[0029] Figure 4 This is a schematic diagram of the matching structure of the balance ring and the permanent magnet block of the utility model.

[0030] Among them, 1 is the shaft, 2 is the balance ring, 3 is the permanent magnet, 4 is the sleeve, 5 is the first axial interface, 6 is the second axial interface, 7 is the permanent magnet block, 8 is the axial end face of the balance ring, and 9 is the axial end face of the permanent magnet block. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of them. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0032] Example 1

[0033] like Figure 1 As shown, the utility model is a rotor assembly with a sleeve, comprising a shaft 1, a balancing ring 2, a permanent magnet 3 and a sleeve 4. The balancing ring 2 is interference fit with the shaft 1, and the radial end surface of the balancing ring 2 is in contact with the radial end surface of the permanent magnet 3. Figure 4As shown, the inner surface of the sleeve 4 is connected to the outer surface of the permanent magnet 3, and the shaft 1 is a cylindrical structure. The permanent magnet structure of the radial flux permanent magnet motor is slender, which is not conducive to the processing size control of the permanent magnet and the sleeve. Therefore, the permanent magnet 3 and the sleeve 4 are segmented along the axial direction, and the intersection of the segmented sleeve-segmented sleeve and the segmented permanent magnet-segmented permanent magnet intersection are mutually offset, which is conducive to controlling the concentricity of the rotor. The combination of the sleeve and the permanent magnet is bonded to eliminate the risk of permanent magnet fracturing caused by the interference fit between the permanent magnet and the sleeve.

[0034] like Figure 3 As shown, the permanent magnet 3 includes a plurality of segmented cylindrical permanent magnet units, and the plurality of segmented cylindrical permanent magnet units are arranged along the axial direction of the shaft 1. The plurality of segmented cylindrical permanent magnet units are equal length structures. Each of the segmented cylindrical permanent magnet units includes a plurality of permanent magnet blocks 7 respectively bonded to the outer surface of the shaft 1. The inner surface and the outer surface of the permanent magnet block 7 are concentric arcs. The permanent magnet block 7 is specifically: (axial length of permanent magnet block / radial thickness of permanent magnet block) ≤ 180. In the case where the radial cross-section of the permanent magnet is small, shortening the axial length of the permanent magnet helps to improve the qualified rate of permanent magnet products and reduce costs; at the same time, the use of an axial multi-segment permanent magnet structure helps to reduce the temperature rise of the motor without affecting the output torque capacity of the motor.

[0035] like Figure 2 As shown, the sleeve 4 includes a plurality of segmented sleeves arranged along the axial direction of the shaft 1, and the inner surface thereof is bonded to the outer surface of the permanent magnet block 7 by glue. The segmented sleeve is specifically: (sleeve axial length / sleeve radial wall thickness) ≤ 180, which shortens the sleeve length, improves the feasibility of sleeve processing, and reduces costs; and the second axial interface 6 of the segmented sleeve and the first axial interface 5 of the segmented cylindrical permanent magnet unit are not in the same radial plane. Staggering the axial interface of the segmented sleeve and the axial interface of the segmented cylindrical permanent magnet helps to improve the runout of the rotor assembly and reduce the risk of friction between the rotor assembly and the stator assembly.

[0036] Example 2

[0037] The present embodiment provides a radial flux permanent magnet motor with a rotor assembly, comprising a stator assembly, a casing assembly and the rotor assembly described in Example 1, wherein the rotor assembly adopts an axial multi-segment permanent magnet structure to help reduce the temperature rise of the motor without affecting the output torque capacity of the motor; at the same time, when the radial cross-section of the permanent magnet is small, the axial length of the permanent magnet is shortened, which helps to improve the qualified rate of permanent magnet products and reduce costs; the bonding combination of the sleeve and the permanent magnet eliminates the risk of permanent magnet fracturing caused by the interference fit between the permanent magnet and the sleeve.

[0038] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A rotor assembly with a sleeve, characterized in that: The invention comprises a shaft (1), a balancing ring (2), a permanent magnet (3) and a sleeve (4); the balancing ring (2) and the shaft (1) are interference fit, the radial end face of the balancing ring (2) is in contact with the radial end face of the permanent magnet (3), and the inner surface of the sleeve (4) is connected to the outer surface of the permanent magnet (3); the permanent magnet (3) and the sleeve (4) are both axially segmented structures, and the segmented interface of the permanent magnet (3) and the segmented interface of the sleeve (4) are staggered.

2. A rotor assembly with a sheath according to claim 1, characterized in that: The permanent magnet (3) comprises a plurality of segmented cylindrical permanent magnet units, and the plurality of segmented cylindrical permanent magnet units are arranged along the axial direction of the shaft (1).

3. A rotor assembly with a sheath according to claim 2, characterized in that: The multiple segmented cylindrical permanent magnet units are structures of equal length.

4. A rotor assembly with a sheath according to claim 2, characterized in that: Each of the segmented cylindrical permanent magnet units comprises a plurality of permanent magnet blocks (7) respectively bonded to the outer surface of the shaft (1).

5. A rotor assembly with a sheath according to claim 4, characterized in that: The inner surface and outer surface of the permanent magnet block (7) are concentric arcs.

6. A rotor assembly with a sheath according to claim 4, characterized in that: The permanent magnet block (7) is specifically: (axial length of the permanent magnet block / radial thickness of the permanent magnet block)≤180.

7. A rotor assembly with a sheath according to claim 4, characterized in that: The sleeve (4) comprises a plurality of segmented sleeves arranged along the axial direction of the shaft (1), the inner surface of which is bonded to the outer surface of the permanent magnet block (7) by glue, and the second axial interface (6) of the segmented sleeve and the first axial interface (5) of the segmented cylindrical permanent magnet unit are not located on the same radial plane.

8. A rotor assembly with a sheath according to claim 7, characterized in that: The segmented sheath is specifically: (sheath axial length / sheath radial wall thickness)≤180.

9. A rotor assembly with a sheath according to claim 1, characterized in that: The shaft (1) is a cylindrical structure.

10. A radial flux permanent magnet motor with a rotor assembly, comprising a stator assembly and a housing assembly, characterized in that: The motor further comprises a rotor assembly as claimed in any one of claims 1-9.

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