Motor rotor

Abstract

The utility model discloses a motor rotor which comprises a rotor iron core block, a permanent magnet, a rotor base and an outer check ring. The same number of rotor iron core blocks and permanent magnets are alternately arranged along the circumference to form a circular ring. The rotor core block is fan-shaped, the bottom surface is provided with a dovetail groove along the radius direction, and the width of the front surface of the rotor core block is slightly greater than that of the bottom surface, so that two surfaces of the rotor core block along the radius direction form a concave inclined surface. The base is in a disc shape, a plurality of protruding dovetail-shaped ribs are arranged in the radius direction, the number of the ribs is the same as that of the rotor iron core blocks, and the rotor iron core blocks are installed and fixed to the base through cooperation of dovetail grooves in the bottoms and the ribs on the base. The permanent magnet is of a columnar structure, the width of the upper end face is slightly smaller than that of the lower end face, and the two faces of the permanent magnet in the radius direction are inclined faces protruding outwards. Each permanent magnet is inserted into a gap formed by two adjacent rotor iron core blocks, is tightly pressed and fixed through an inclined plane, and is magnetized along the circumferential tangential direction, and the magnetizing directions of two adjacent permanent magnets are opposite; the outer check ring is fixedly installed on the outer circumference of a circular ring formed by the base, the rotor iron core block and the permanent magnet, and the rotor iron core block and the permanent magnet are fixed in the radial direction.

Description

Technical Field

[0001] The present invention relates to an axial motor rotor and belongs to the technical field of permanent magnet motors. Background Art

[0002] Most of the existing axial flux permanent magnet motors adopt surface-mounted permanent magnet rotors. The permanent magnets are fixed on the motor rotor disc by using adhesives, or in a mechanical fixing manner, the permanent magnets are embedded in the pores of the rotor bracket, and then the outer ring of the rotor is wound with glass fiber or carbon fiber for reinforcement. The former is affected by the performance of the adhesive and there is a risk of adhesive aging and permanent magnet detachment; the latter has relatively high requirements for processing and manufacturing, which increases the production cost. CN117616668 A discloses a co-molding assembly technology, in which the permanent magnets and the supporting members between the permanent magnets are placed in a suitable mold, and an uncured sheet molding compound such as a thermosetting resin is injected for in-situ molding. The supporting member and magnet combination body made by using the co-molding technology has a relatively high overall stiffness.

[0003] The above methods are only applicable to surface-mounted permanent magnet rotors. A major defect of the surface-mounted permanent magnet rotor is that the permanent magnet is directly exposed to the air-gap magnetic field, and a large eddy current will be generated on the surface of the permanent magnet, causing the permanent magnet to heat up and posing a risk of demagnetization. To solve this problem, it is often necessary to adopt a spliced magnet, which greatly increases the process difficulty and cost; for the permanent magnet motor with a surface-mounted rotor, since the d-axis inductance and the q-axis inductance are the same, it is not conducive to field-weakening speed regulation; in addition, the surface-mounted permanent magnet rotor must add a ferromagnetic rotor back iron to form a magnetic circuit, and in order to avoid magnetic circuit saturation of the back iron, the back iron needs a certain thickness, which will increase the weight of the rotor and limit the use of rotor materials, bringing difficulties to the lightweight design.

[0004] In recent years, people have shown increasing interest in axial flux motors. The axial flux motor has a flexible magnetic circuit structure and can adopt a single-rotor single-stator structure or a double-rotor single-stator structure. However, during the operation of the axial flux motor, the magnetic field alternates in three-dimensional space, and the rotor is simultaneously subjected to complex axial forces and radial forces, posing great challenges to the design of the rotor magnetic circuit and the installation and fixation of the magnets.

[0005] The purpose of the present invention is to provide a brand-new rotor structure to overcome or mitigate some of the disadvantages of the existing rotor designs. Summary of the Invention

[0006] To solve the above problems, the present invention provides an axial flux motor rotor. The structure of this motor rotor can improve the utilization rate of permanent magnets, and has reliable connection and simple process, and is suitable for various axial flux motors.

[0007] A motor rotor includes rotor core blocks, permanent magnets, a base, and an outer retaining ring. The rotor core blocks and the permanent magnets are arranged alternately along the circumference to form a ring. The rotor core blocks are fixed to the base through the dovetail grooves at the bottom. Two adjacent rotor core blocks clamp the permanent magnet using the inclined surfaces on both sides, making it close to the base and fixed along the circumferential direction. The outer retaining ring is installed on the outer circle of the base to limit the rotor core blocks and the permanent magnets in the radial direction to overcome the centrifugal force during rotor rotation.

[0008] For a motor rotor according to the present application, the number of rotor core blocks is the same as the number of permanent magnets.

[0009] For a motor rotor according to the present application, the rotor core blocks are fan-shaped, with dovetail grooves opened along the radial direction at the bottom surface. The width of the top surface of the rotor core is slightly larger than that of the bottom surface, making the two surfaces along the radial direction be concave inclined surfaces.

[0010] For a motor rotor according to the present application, the permanent magnet is a columnar structure, the width of the upper end surface is slightly smaller than that of the lower end surface, and its two side surfaces are convex inclined surfaces; the permanent magnet is magnetized along the circumferential tangential direction, and the magnetization directions of two adjacent permanent magnets are opposite.

[0011] For a motor rotor according to the present application, the base is disc-shaped, with protruding dovetail-shaped ribs evenly distributed along the radial direction. The number of ribs is the same as the number of rotor core blocks.

[0012] For a motor rotor according to the present application, the sizes of the dovetail grooves on the rotor core blocks and the ribs on the base are obtained through magnetic circuit calculation. On the premise of ensuring that the magnetic circuit of the rotor core is not saturated, the dovetail grooves are preferably selected with larger sizes, and the corresponding rib sizes will also be larger. This can reduce the weight of the rotor and increase the mechanical strength of the rotor.

[0013] For a motor rotor according to the present application, the rotor core blocks are made of magnetic conductive materials, the permanent magnets are made of strong magnetic materials, and the base and the outer retaining ring are made of non-magnetic conductive materials.

[0014] For a motor rotor according to the present application, its installation method is as follows: the rotor core blocks are inserted from the outer diameter end of the base and are fixed to the base through the cooperation of the dovetail grooves at the bottom and the ribs on the base; the permanent magnets are inserted into the gaps formed between two adjacent rotor core blocks, are fixed by pressing through the inclined surfaces, and are then fixed in the radial direction by the outer retaining ring.

[0015] Advantages of the present invention:

[0016] For the motor rotor proposed by the present invention, the rotor core and the permanent magnet are alternately installed to form an embedded magnetic circuit, which has the effect of concentrating the magnetic field, can enhance the effective magnetic field of the motor, and improve the performance of the motor.

[0017] The rotor core is fixedly installed on the rotor base through the dovetail grooves at the bottom, and at the same time, the permanent magnets are fixed by using the inclined planes on both sides of the rotor core, with simple assembly and firm fixation. The sizes of the dovetail grooves at the bottom of the rotor core are designed according to the magnetic field distribution. The dovetail grooves are maximally opened in the area with the weakest magnetic field intensity, which can reduce the weight of the rotor and enhance the mechanical strength of the rotor.

[0018] The permanent magnets adopt regular columnar structures, with the two sides processed into inclined planes, and are fixedly installed through cooperation with the rotor core blocks. The overall processing of the permanent magnets is simple, without the need for segmentation, with small eddy current losses, reducing the manufacturing cost.

[0019] For the motor rotor proposed by the present invention, any lightweight non-magnetic material can be used for the rotor base, which is conducive to the lightweight design of the motor rotor. Brief Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a motor rotor according to the present invention;

[0021] Figure 2 is a schematic diagram of a single rotor core block 1 according to the present invention;

[0022] Figure 3 is a front view schematic diagram of a single rotor core block 1 according to the present invention;

[0023] Figure 4 is a schematic diagram of a single permanent magnet 2 according to the present invention;

[0024] Figure 5 is a top view schematic diagram and magnetization direction of a single permanent magnet 2 according to the present invention;

[0025] Figure 6 is a schematic diagram of the rotor base 3 according to the present invention;

[0026] Figure 7 is a schematic diagram of the outer retaining ring 4 according to the present invention; Detailed Description of the Invention

[0027] The present invention will be further described below in conjunction with the drawings and specific embodiments:

[0028] As Figure 1 shown, a motor rotor according to the present invention includes a plurality of rotor core blocks 1, a plurality of permanent magnets 2, a rotor base 3, and an outer retaining ring 4. Each rotor core block has the same structure, and the shapes of each permanent magnet are also exactly the same. The number of rotor core blocks 1 is the same as that of permanent magnets 2. The rotor core blocks 1 and the permanent magnets 2 are alternately arranged along the circumference to form a ring, and are fixed to the rotor base through the following structure.

[0029] The single rotor core block 1 is integrally machined from a magnetic conductive material or can be formed by stacking silicon steel sheets. Its structure is as shown in Figure 2 and the front view is as shown in Figure 3 . A dovetail groove 11 is formed on the bottom surface 13 of the single rotor core block 1, and the width of the bottom surface 13 is slightly smaller than the width of the front surface 14, so that the two side surfaces 12a and 12b of the rotor core block 1 are inclined surfaces.

[0030] The rotor base 3 is disc-shaped, and the schematic structural diagram is as shown in Figure 6 . A plurality of protruding ribs 31 are evenly distributed along the circumference in the radial direction on the rotor base 3. The number of the ribs is the same as the number of the rotor core blocks 1, and the positions of the ribs determine the installation positions of the rotor core blocks 1 on the rotor base 3. The shape and size of the ribs 31 are determined by the shape of the dovetail groove 11 on the rotor core block 1. The ribs 31 and the dovetail groove 11 are meshed with each other to fix the rotor core block 1 to the rotor base 3. During installation, the bottom surface 13 of the single rotor core block 1 is close to the outer circumference of the rotor base 3, and the dovetail groove 11 is aligned with the ribs 31 and inserted from the outer diameter direction to the inner diameter direction. The single rotor core block 1 is fixed to the rotor base 3 through the meshing of the ribs 31 and the dovetail groove 11. By repeating this process, all the rotor core blocks are fixedly installed on the rotor base 3.

[0031] According to a motor rotor of the present application, the permanent magnet 2 is of a columnar structure, and the schematic diagram is as shown in Figure 4 . The front surface 23 faces outwards and is the working surface facing the air gap. The bottom surface 24 is the installation surface and needs to be closely attached to the rotor base 3. The width of the bottom surface 24 is slightly larger than that of the front surface 23, so that the two side surfaces 21 and 22 of the permanent magnet 1 become inclined surfaces. The top view of the permanent magnet 2 is as shown in Figure 5 , and it can be seen that the circumferential width of the front surface 23 is smaller than the circumferential width of the bottom surface 24. Figure 5 The "→" in

[0032] A motor rotor according to the present application, the specific installation method of its permanent magnet 2 is to face the front surface 23 of the permanent magnet 2 upward and the bottom surface 24 toward the rotor base 3, and insert it between two rotor core blocks 1 along the radial direction from the outer circumference of the rotor base 3, and make the two inclined surfaces 12a, 12b of the rotor core block 1 and the two inclined surfaces 21, 22 of the permanent magnet 2 press against each other. Since the width of the bottom surface 24 of the permanent magnet 2 is greater than the width of the front surface 23, and the inclined surface 12a or 12b of the rotor core block 1 and the inclined surface 12b or 12a of the adjacent another rotor core form a hole position that is narrow at the top and wide at the bottom, the permanent magnet 2 is fixed to the rotor base 3. Repeat the above operation to fixedly install multiple permanent magnets on the rotor base 3 to form a complete multi-pole magnetic circuit.

[0033] A motor rotor according to the present application, after multiple rotor core blocks 1 and permanent magnets 2 are both fixed to the rotor base 3, the outer retaining ring 4 is press-fitted onto the outer circumference of the rotor base 3 by a tight fit to fasten the rotor core blocks 1 and the permanent magnets 2 in the outer diameter direction to prevent them from falling off radially during high-speed rotation of the rotor.

[0034] In this embodiment, the rotor core block is fixed to the rotor base through a dovetail groove. Since the material of the rotor core is a ferromagnetic material with a relatively large density, and the rotor base is a lightweight material, the overall weight of the rotor core after opening the dovetail groove is reduced. At the same time, the inclined surface of the rotor core is used to clamp the permanent magnet so that it is close to the rotor base. This structure also makes the area of the permanent magnet exposed in the air gap smaller, reducing the generation of surface eddy current.

[0035] In other embodiments, the base can also be designed into a structure with an outer edge. The rotor core block and the permanent magnet are inserted from the inner diameter of the base and fixed to the base through a dovetail groove to form a ring, and then an inner retaining ring is installed at the inner diameter, and the effect is the same.

[0036] The described embodiments are the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Without departing from the essential content of the present invention, any obvious improvements, substitutions or variations that those skilled in the art can make, as long as they do not deviate from the content of the specification of the present invention or exceed the scope defined by the claims of the present invention, all fall within the protection scope of the present invention.

Claims

1. A motor rotor, characterized in that: The motor rotor includes rotor core blocks (1), permanent magnets (2), a base (3), and an outer retaining ring (4). The rotor core blocks (1) are fixedly installed on the base (3) through dovetail grooves. The permanent magnets (2) are embedded between two rotor core blocks (1). A plurality of rotor core blocks (1) and an equal number of permanent magnets (2) are assembled into a ring to form the magnetic circuit of the permanent magnet motor rotor. The permanent magnet (2) is a regular columnar body. The width of the bottom surface in contact with the base (3) is slightly larger than that of the top surface, and its two side surfaces are inclined surfaces protruding outward. The rotor core block (1) is fan-shaped and has the same thickness as the permanent magnet (2). A dovetail groove is opened along the radial direction on the bottom surface of the rotor core block (1). The width of the top surface of the rotor core block (1) is slightly larger than that of the bottom surface, so that the two surfaces along the radial direction are concave inclined surfaces. The base (3) is disc-shaped, and a number of protruding dovetail-shaped ribs are arranged along the radial direction. The number of ribs is the same as that of the rotor core blocks (1). The shape of the ribs and the dovetail groove on the bottom surface of the rotor core block (1) form a male-female insertion structure.

2. The motor rotor according to claim 1, wherein, Both the base (3) and the outer retaining ring (4) are integrally processed from non-magnetic lightweight materials.

3. The motor rotor according to claim 1, wherein, The size of the dovetail groove opened on the bottom surface of the rotor core block (1) is obtained through magnetic circuit calculation, and it should be ensured that the dovetail groove will not cause magnetic circuit saturation of the rotor core block (1).

4. The motor rotor according to claim 1, wherein, The shape of the ribs in the base (3) is determined by the shape of the dovetail groove opened on the rotor core block (1).

5. The motor rotor according to claim 1, wherein, The outer retaining ring (4) is fixedly installed on the outer circumference of the ring formed by the base (3), the rotor core blocks (1), and the permanent magnets (2), and fixes the rotor core blocks (1) and the permanent magnets (2) in the radial direction.

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