Structure of disc type Halbach magnet array rotor disc and manufacturing method of disc type Halbach magnet array rotor disc

Abstract

The invention relates to a structure of a disc type Halbach magnet array rotor disc and a manufacturing method thereof, the rotor disc comprises a rotor support, a Halbach magnet array and a magnetic back plate which are axially arranged and connected in sequence facing a motor air gap side, fiber ring belts are wound on the outer sides of the rotor support, the Halbach magnet array and the magnetic back plate, and the fiber ring belts are wound on the outer sides of the rotor support, the Halbach magnet array and the magnetic back plate. The rotor support and the magnetic back plate are in fastening connection through the sunk screw, the rotor support and the magnetic back plate are used for installing and positioning the Halbach magnet array and providing supporting protection when the motor runs, and the fiber ring belt and the sunk screw are used for achieving axial fastening of the rotor disc and providing radial protection when the motor runs. Compared with the prior art, supporting protection and circumferential, axial and radial positioning of the Halbach magnet array can be reliably achieved, the utilization rate of the permanent magnets is improved, and the air-gap magnetic field of the motor is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of disc-type coreless permanent magnet motors, and in particular to the structure of a disc-type Halbach magnet array rotor disc and a manufacturing method thereof. Background Art

[0002] Disc-type coreless permanent magnet motors have the advantages of high power / torque density, high efficiency, low torque fluctuation, and smooth operation. They have been rapidly promoted and applied in industries such as direct-drive power generation systems, flywheel energy storage, high-precision servo systems, and all-electric propulsion systems.

[0003] According to the number of stators and rotors, relative positions and main magnetic circuit classification, there are four main topological structures of existing disc permanent magnet motors, namely single stator single rotor structure, double stator single rotor structure, single stator double rotor structure and multi-disk structure. Among them, the stator of the single stator double rotor structure is a coreless and toothless winding disk in the middle, and the rotor usually uses Halbach magnet arrays on both sides. It has higher power / torque density and efficiency, no tooth torque fluctuation, small size, light weight and other excellent performances, and has higher development and promotion potential.

[0004] Although the single-stator dual-rotor Halbach magnet array coreless permanent magnet motor has been the subject of nearly 20 years of theoretical research, electromagnetic simulation and prototype production, it is still not mature enough in terms of manufacturing technology, production equipment and processes, making it difficult to carry out mass production, and the product performance and quality are not stable enough. In particular, due to the axial electromagnetic attraction between the rotor disks and the radial centrifugal force of the rotor disks when the motor is running, the air gap length on both sides of the stator disk is uneven in the circumferential direction, the rotor disk is deformed and scrapes against the stator disk, and moves radially, and the vibration and noise increase.

[0005] In principle, the Halbach magnet array can enhance the magnetic field on the side of the motor facing the air gap and weaken the magnetic field on the other side, so there is no need for an iron core back yoke. However, this will result in the permanent magnets not being fully utilized, and the magnetic field on one side of the motor's air gap will not be strong enough. At the same time, the Halbach magnet array also needs to be positioned and supported by other components.

[0006] In the prior art, Chinese patent CN109713819A discloses a high-strength Halbach permanent magnet array rotor structure, in which semicircular grooves are arranged between the axial centers of the permanent magnet blocks, and fixing pins are inserted into the assembled circular grooves to achieve circumferential and axial positioning and high strength of the rotor. However, since the fixing pins occupy the space of the permanent magnets, this will undoubtedly reduce the magnetomotive force and introduce high harmonics. In addition, the processing and assembly difficulty of this solution is also relatively large, and it is difficult to promote and apply in practice.

[0007] Therefore, there is an urgent need to solve the circumferential, axial and radial positioning support of the Halbach magnet array on the rotor disk, as well as how to improve the utilization rate of permanent magnets and enhance the air gap magnetic field of the motor. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a disc-type Halbach magnet array rotor disc structure and a manufacturing method thereof, which can reliably realize the support protection and circumferential, axial and radial positioning of the Halbach magnet array, and improve the utilization rate of permanent magnets and enhance the air gap magnetic field of the motor.

[0009] The object of the present invention can be achieved through the following technical scheme: a structure of a disc-type Halbach magnet array rotor disk, comprising a rotor bracket, a Halbach magnet array, and a magnetic backplate which are axially arranged and connected in sequence facing the air gap side of the motor, the outer sides of the rotor bracket, the Halbach magnet array, and the magnetic backplate are wrapped with fiber ring belts, the rotor bracket and the magnetic backplate are fastened and connected by countersunk screws, the rotor bracket and the magnetic backplate are used to install and position the Halbach magnet array, and provide support and protection when the motor is running, the fiber ring belt and the countersunk screws are used to achieve axial fastening of the rotor disk, and provide radial protection when the motor is running.

[0010] Furthermore, the Halbach magnet array is composed of a plurality of opposite poles assembled in sequence, each pole is composed of 2 to 6 permanent magnets arranged in a magnetizing direction from the axial positive direction to the circumferential direction and then to the axial reverse direction, wherein the axially magnetized permanent magnet is located at the center of the pole, and a radial second groove is provided on the circumferential center surface of the side close to the magnetic back plate for being engaged with the magnetic back plate;

[0011] The circumferentially magnetized permanent magnets are located at the circumferential centers of adjacent opposite magnetic poles, and a radial first groove is provided on the circumferential center surface of the side close to the rotor bracket for being engaged and connected with the rotor bracket.

[0012] Furthermore, when the magnetic poles are composed of 2, 4 or 6 permanent magnets, the circumferential center between adjacent magnetic poles is a circumferentially magnetized permanent magnet, and the radial first groove is arranged on the side of the circumferentially magnetized permanent magnet center facing the motor air gap;

[0013] When the magnetic poles are arranged by 3 or 5 permanent magnets, the circumferential center between adjacent magnetic poles is the radial dividing line between the two permanent magnets, and the radial first groove is arranged on the side of the radial dividing line between the two permanent magnets facing the motor air gap.

[0014] Furthermore, the rotor bracket is sleeved and installed on the motor shaft, including a support part and a magnetic steel mounting part, the support part and the magnetic steel mounting part are distributed radially from the inside to the outside, the countersunk screw is penetrated and connected between the support part and the magnetic back plate, and the magnetic steel mounting part is mutually embedded and connected with the circumferentially magnetized permanent magnets in the Halbach magnet array.

[0015] Furthermore, a first convex strip is radially arranged on a side of the magnetic steel mounting portion facing the permanent magnet, and the first convex strip is correspondingly engaged with a radial first groove of the Halbach magnet array to achieve axial positioning of the Halbach magnet array.

[0016] Furthermore, the axial thickness of the support portion is equal to the sum of the axial thicknesses of the magnetic steel mounting portion and the permanent magnet, and the radial length of the magnetic steel mounting portion is equal to the radial length of the permanent magnet.

[0017] Furthermore, the support portion is provided with ventilation holes for heat dissipation, blind holes for installing countersunk screws, and shaft holes for connecting the motor shaft.

[0018] Further, the magnetic back plate includes an annular adhesive magnetic steel portion located at the radial center and a surrounding plate located at the radial outer circle, and the adhesive magnetic steel portion is provided with a second convex strip, and the second convex strip is correspondingly engaged with the radial second groove of the Halbach magnet array to achieve axial positioning of the Halbach magnet array;

[0019] The enclosure plate is used to achieve radial positioning of the Halbach magnet array;

[0020] The sticking magnetic steel part is provided with a screw hole for installing a countersunk screw.

[0021] Furthermore, the axial height of the enclosure plate is 1 / 3 of the axial thickness of the permanent magnet.

[0022] A method for manufacturing a disc-type Halbach magnet array rotor disc comprises the following steps:

[0023] S1, parallel and independent processing of rotor bracket, magnetic back plate and magnetization, cutting and grinding of permanent magnets;

[0024] S2, applying glue to the joint surface between the magnetic steel mounting portion of the rotor bracket and the permanent magnet, and realizing the axial positioning of the permanent magnet by the cooperation of the first convex strip and the radial first groove, so as to form a Halbach magnet assembly array;

[0025] S3, glue is applied to the bonding surface of the magnetic steel part of the magnetic back plate and the permanent magnet, and the permanent magnet is further axially positioned by the cooperation of the second convex strip and the radial second groove, and the radial positioning of the permanent magnet is achieved by the surrounding plate of the outer circle of the magnetic back plate, and then the countersunk screws are installed;

[0026] S4. Wind the fiber ring belt and conduct assembly quality inspection.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The present invention is designed to sequentially arrange the rotor support, Halbach magnet array, and magnetic back plate axially facing the air gap side of the motor, and wind the fiber ring belt around the outer side of the rotor support, Halbach magnet array, and magnetic back plate, and fasten the rotor support and magnetic back plate with countersunk screws, and use the rotor support and magnetic back plate to install and position the Halbach magnet array, and provide support protection when the motor is running; use the fiber ring belt and countersunk screws to achieve axial fastening of the rotor disk, and provide radial protection when the motor is running. Thus, on the one hand, the support protection and circumferential and axial positioning of the Halbach magnet array are achieved through the rotor support; on the other hand, the magnetic back plate improves the utilization rate of the permanent magnet, enhances the air gap magnetic field of the motor, and achieves the support protection and axial and radial positioning of the Halbach magnet array; in addition, the fiber ring belt is used to achieve radial positioning of the Halbach magnet array, and overcome the centrifugal force when the rotor is running, thereby effectively protecting the rotor disk.

[0029] The present invention designs a radial first groove and a radial second groove in the Halbach magnet array to respectively engage with the first convex strip on the rotor bracket and the second convex strip on the magnetic back plate, thereby ensuring that the rotor bracket and the magnetic back plate can achieve circumferential and axial installation positioning of the assembled Halbach magnet array.

[0030] The present invention arranges a surrounding plate on the radial outer circle of the magnetic back plate, and the axial height of the surrounding plate is 1 / 3 of the thickness of the permanent magnet, which can reliably realize the radial positioning when the Halbach magnet array is installed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure explosion of the present invention;

[0032] Figure 2 is a schematic diagram of the Halbach magnet array in Example 1;

[0033] Figure 3 Schematic diagram of a permanent magnet under one magnetic pole in Example 1;

[0034] Figure 4 It is an axial view of the magnetization direction of the permanent magnet in the first embodiment;

[0035] Figure 5 It is a schematic diagram of the structure of the rotor support in the present invention;

[0036] Figure 6It is a schematic diagram of the structure of the magnetic back plate in the present invention;

[0037] Figure 7 It is a schematic diagram of the manufacturing method of the present invention;

[0038] Figure 8 A three-dimensional view of the permanent magnet after being installed on the rotor bracket;

[0039] Fig. 9 A three-dimensional view after installing the magnetic backing plate and countersunk screws;

[0040] Fig.10 This is a schematic diagram of a rotor disk made after tying the fiber ring belt;

[0041] Fig.11 It is a schematic diagram of a radial cross section of a permanent magnet under one magnetic pole in the second embodiment;

[0042] Explanation of the markings in the figure: 1. rotor bracket, 2. Halbach magnet array, 3. magnetic back plate, 4. fiber ring belt, 5. countersunk screw, 101. support part, 102. magnetic steel mounting part, 103. first convex strip, 104. ventilation hole, 105. shaft hole, 106. blind hole, 201. axially magnetized permanent magnet, 202. second groove, 203. circumferentially magnetized permanent magnet, 204. first groove, 301. magnetic steel pasting part, 302. enclosure, 303. second convex strip, 304. screw hole. DETAILED DESCRIPTION

[0043] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, a structure of a disc-type Halbach magnet array rotor disk comprises a rotor bracket 1, a Halbach magnet array 2, and a magnetic back plate 3 which are axially arranged and connected in sequence facing the air gap side of the motor, wherein a fiber ring belt 4 is wound around the outer sides of the rotor bracket 1, the Halbach magnet array 2, and the magnetic back plate 3, and the rotor bracket 1 and the magnetic back plate 3 are fastened together by countersunk screws 5, the rotor bracket 1 and the magnetic back plate 3 are used to install and position the Halbach magnet array 2, and provide support and protection when the motor is running, and the fiber ring belt 4 and the countersunk screws 5 are used to achieve axial fastening of the rotor disk, and provide radial protection when the motor is running.

[0045] The Halbach magnet array 2 is composed of a plurality of opposite poles assembled in sequence, and each pole is composed of 2 to 6 permanent magnets arranged in a magnetizing direction from the positive axial direction to the circumferential direction and then to the reverse axial direction. When the pole is composed of 2, 4 or 6 permanent magnets, the circumferential center between adjacent poles is the circumferentially magnetized permanent magnet; when the pole is composed of 3 or 5 permanent magnets, the circumferential center between adjacent poles is the radial dividing line between the two permanent magnets.

[0046] Embodiment 1

[0047] In this embodiment, the Halbach magnet array 2 has 10 magnetic poles, each of which is composed of two permanent magnets. Figure 2 to Figure 4 As shown, Figures 2 to 4 They are a three-dimensional view of the Halbach magnet array 2, two permanent magnets under one magnetic pole, and an axial view of the magnetization direction of the permanent magnets from the air gap side of the motor. Among the two permanent magnets, the axially magnetized permanent magnet 201 is located at the center of the magnetic pole, and a radial second groove 202 is provided on the circumferential center surface of the side close to the magnetic back plate 3 for interlocking connection with the magnetic back plate 3;

[0048] The circumferentially magnetized permanent magnet 203 is located at the circumferential center of adjacent opposite magnetic poles, and a radial first groove 204 is provided on the circumferential center surface of the side close to the rotor support 1 for being engaged with the rotor support 1 .

[0049] In this embodiment, the first groove 204 is located at the radial center of the circumferentially magnetized permanent magnet 203 and is close to one side of the rotor bracket 1; the second groove 202 is located at the radial center of the axially magnetized permanent magnet 201 and is close to one side of the magnetic back plate 3; the Halbach magnet array 2 is composed of multiple permanent magnets whose magnetization directions change through 5 cycles and are circumferentially assembled, and the overall structure is an annular structure.

[0050] Figure 5 The figure shows an axial view of the rotor bracket 1 mounting magnetic steel surface and a radial cross-sectional view along A-A1. The axial center of the rotor bracket 1 is an axial hole 105, which is used to be mounted on the motor shaft. The rotor bracket 1 is made of high-strength and high-thermal-conductivity composite insulating materials such as polyimide, carbon fiber, ceramics, etc., and is radially divided into a support portion 101 and a magnetic steel mounting portion 102 from the inside to the outside. The axial thickness of the support portion 101 is the sum of the axial thickness of the magnetic steel mounting portion 102 and the magnetic steel. Under the premise of ensuring the support strength, ventilation holes 104 for heat dissipation are uniformly arranged in the circumference of the inner circle, and blind holes 106 with threads are uniformly arranged in the circumference of the outer circle connected to the magnetic back plate 3. The magnetic steel mounting portion 102 is radially provided with a first convex strip 103 on one side close to the magnetic steel, and cooperates with the first groove 204 of the circumferentially magnetized permanent magnet to achieve the circumferential and axial positioning of the Halbach magnet array 2. The radial length of the magnetic steel mounting portion 102 is equal to the radial length of the magnetic steel.

[0051] Figure 6The figure shows the axial view of the magnetic steel surface of the magnetic back plate 3 and the radial cross-section along B-B1. The magnetic back plate 3 is made of high-permeability ferromagnetic material with sufficient mechanical strength and is a thin plate structure, which is used to further enhance the air gap magnetic field of the motor and the support and positioning of the Halbach magnet array 2. A screw hole 304 is provided at the radial inner circle to cooperate with the blind hole 106 with threads on the rotor bracket 1 for installing the countersunk screw 6; the magnetic steel portion 301 pasted in the radial center is provided with a second convex strip 303, which cooperates with the second groove 202 of the axially magnetized permanent magnet to achieve the circumferential and axial positioning of the Halbach magnet array 2; a protruding outer circle plate 302 is provided at the radial outer circle, and its axial height is 1 / 3 of the magnetic steel thickness, because the radial positioning of the Halbach magnet array 2 is achieved when it is installed.

[0052] The present invention also provides a method for manufacturing the rotor disk, such as Figure 7 As shown, including:

[0053] S1, parallel and independent processing of rotor bracket, magnetic back plate and magnetization, cutting and grinding of permanent magnets;

[0054] S2, glue is applied to the joint surface between the magnetic steel mounting part of the rotor bracket and the permanent magnet, and the circumferential and axial positioning of the permanent magnet is achieved by the cooperation of the first convex strip and the radial first groove to form a Halbach magnet assembly array (such as Figure 8 shown);

[0055] S3. Apply glue to the joint surface of the magnetic steel part of the magnetic back plate and the permanent magnet, and rely on the cooperation of the second convex strip and the radial second groove to achieve the circumferential and axial positioning of the permanent magnet, and rely on the outer circle of the magnetic back plate to achieve the radial positioning of the permanent magnet, and then install the countersunk screws (such as Fig. 9 shown);

[0056] S4, winding fiber ring (such as Fig.10 As shown), and finally the assembly quality inspection is carried out.

[0057] It should be noted that in practical applications, the position and depth of the first groove and the second groove are based on the principle of not affecting the magnetic flux of the main magnetic field and achieving circumferential and axial positioning. The groove type can be selected from a variety of shapes such as semicircle, isosceles triangle, isosceles trapezoid, etc., depending on the difficulty of cutting and grinding the permanent magnet.

[0058] Embodiment 2

[0059] The difference between this embodiment and the first embodiment is that each magnetic pole in the Halbach magnet array is composed of three permanent magnets, and the radial cross section of the Halbach magnet array and its grooves (including the first groove and the second groove) are as follows: Fig.11As shown in the figure, there are 4 poles in the circumferential direction, the magnetizing direction of the magnet changes for 2 cycles, the second groove is located at the permanent magnet in the center of the magnetic pole and is arranged away from the circumferential center surface of the motor air gap side, the first groove is located at the center of the two permanent magnets of the adjacent opposite magnetic poles and is arranged close to the circumferential center surface of the motor air gap side, and the dividing line of the two permanent magnets is the radial center line of the first groove.

[0060] In summary, this solution uses a rotor bracket made of high-strength and high-thermal conductivity composite insulating material to achieve support protection and circumferential and axial positioning of the Halbach magnet array, and uses a high-permeability ferromagnetic material to make a magnetic backplate, which improves the utilization rate of permanent magnets, enhances the air gap magnetic field of the motor, and further achieves support protection and circumferential and radial positioning of the Halbach magnet array. The fiber ring belt further achieves radial positioning of the Halbach magnet array and overcomes the centrifugal force during rotor operation to protect the rotor disk. In this solution, the materials used to make the rotor bracket and the magnetic backplate are cheap and easy to obtain, and the manufacturing equipment and processes involved are mature and suitable for mass production. Applying this solution in practice can achieve low-cost and mass production of Halbach magnet array rotor disks, simplify the manufacturing process, improve motor production and operation efficiency, improve performance, and promote the productization and serialization of disc-type coreless permanent magnet motors.

Claims

1. A disc-type Halbach magnet array rotor disc structure, characterized in that: The invention comprises a rotor support (1), a Halbach magnet array (2), and a magnetic back plate (3) which are axially arranged and connected in sequence facing the air gap side of the motor, wherein the outer sides of the rotor support (1), the Halbach magnet array (2), and the magnetic back plate (3) are wound with a fiber ring belt (4), and the rotor support (1) and the magnetic back plate (3) are fastened and connected by countersunk screws (5). The rotor support (1) and the magnetic back plate (3) are used to install and position the Halbach magnet array (2) and provide support and protection when the motor is running, and the fiber ring belt (4) and the countersunk screws (5) are used to achieve axial fastening of the rotor disk and provide radial protection when the motor is running.

2. The structure of a disc-type Halbach magnet array rotor disc according to claim 1, characterized in that: The Halbach magnet array (2) is composed of a plurality of opposite magnetic poles assembled in sequence, each magnetic pole being composed of 2 to 6 permanent magnets arranged in a magnetizing direction from an axial positive direction to a circumferential direction and then to an axial reverse direction, wherein the axially magnetized permanent magnet (201) is located at the center of the magnetic pole, and a radial second groove (202) is provided on the circumferential center surface of a side close to the magnetic back plate (3) for being engaged and connected with the magnetic back plate (3); The circumferentially magnetized permanent magnets (203) are located at the circumferential centers of adjacent opposite magnetic poles, and a radial first groove (204) is provided on the circumferential center surface of the side close to the rotor support (1) for being engaged and connected with the rotor support (1).

3. The structure of a disc-type Halbach magnet array rotor disc according to claim 2, characterized in that: When the magnetic poles are composed of 2, 4 or 6 permanent magnets arranged in an array, the circumferential center between adjacent magnetic poles is a circumferentially magnetized permanent magnet (203), and the radial first groove (204) is arranged on a side of the center of the circumferentially magnetized permanent magnet (203) facing the air gap of the motor; When the magnetic poles are composed of 3 or 5 permanent magnets, the circumferential center between adjacent magnetic poles is the radial dividing line between the two permanent magnets, and the radial first groove (204) is arranged on the side of the radial dividing line between the two permanent magnets facing the air gap of the motor.

4. The structure of a disc-type Halbach magnet array rotor disc according to claim 2, characterized in that: The rotor bracket (1) is sleeved and mounted on the motor shaft, and comprises a support portion (101) and a magnetic steel mounting portion (102), wherein the support portion (101) and the magnetic steel mounting portion (102) are radially distributed from the inside to the outside, the countersunk screw (5) is penetrated and connected between the support portion (101) and the magnetic back plate (3), and the magnetic steel mounting portion (102) and the circumferentially magnetized permanent magnet (203) in the Halbach magnet array (2) are mutually embedded and connected.

5. The structure of a disc-type Halbach magnet array rotor disc according to claim 4, characterized in that: A first convex strip (103) is radially arranged on one side of the magnetic steel mounting portion (102) facing the permanent magnet, and the first convex strip (103) is correspondingly engaged with the radial first groove (204) to achieve axial positioning of the Halbach magnet array (2).

6. The structure of a disc-type Halbach magnet array rotor disc according to claim 4, characterized in that: The axial thickness of the support portion (101) is equal to the sum of the axial thicknesses of the magnetic steel mounting portion (102) and the permanent magnet, and the radial length of the magnetic steel mounting portion (102) is equal to the radial length of the permanent magnet.

7. The structure of a disc-type Halbach magnet array rotor disc according to claim 4, characterized in that: The support portion (101) is provided with ventilation holes (104) for heat dissipation, blind holes (106) for installing countersunk screws (5), and shaft holes (105) for connecting to the motor shaft.

8. The structure of a disc-type Halbach magnet array rotor disc according to claim 5, characterized in that: The magnetic back plate (3) comprises an annular adhesive magnetic steel portion (301) located at the radial center and a surrounding plate (302) located at the radial outer circle, the adhesive magnetic steel portion (301) is provided with a second convex strip (303), and the second convex strip (303) is correspondingly engaged with the radial second groove (202) to achieve axial positioning of the Halbach magnet array (2); The enclosure plate (302) is used to achieve radial positioning of the Halbach magnet array (2); The adhesive magnetic steel portion (301) is provided with a screw hole (304) for installing a countersunk screw (5).

9. The structure of a disc-type Halbach magnet array rotor disc according to claim 8, characterized in that: The axial height of the enclosure plate (302) is 1 / 3 of the axial thickness of the permanent magnet.

10. A method for manufacturing a disk-type Halbach magnet array rotor disk, used for manufacturing a disk-type Halbach magnet array rotor disk structure as claimed in claim 8, characterized in that: The following steps are involved: S1, parallel and independent processing of rotor bracket, magnetic back plate and magnetization, cutting and grinding of permanent magnets; S2, applying glue to the joint surface between the magnetic steel mounting portion of the rotor bracket and the permanent magnet, and realizing the axial positioning of the permanent magnet by the cooperation of the first convex strip and the radial first groove, so as to form a Halbach magnet assembly array; S3, glue is applied to the joint surface of the magnetic steel part of the magnetic back plate and the permanent magnet, and the axial positioning of the permanent magnet is achieved by the cooperation of the second convex strip and the radial second groove, and the radial positioning of the permanent magnet is achieved by the surrounding plate of the outer circle of the magnetic back plate, and then the countersunk screws are installed; S4. Wind the fiber ring belt and conduct assembly quality inspection.

Images