Rotor structure and axial flux motor

Abstract

The utility model relates to the technical field of motors, in particular to a rotor structure and an axial magnetic flux motor, and aims to solve the problems that an existing rotor is high in eddy current loss and harmonic loss and a permanent magnet emits heat. The rotor structure provided by the utility model comprises a main back iron, an auxiliary back iron and a permanent magnet. The auxiliary back iron is arranged to be of an annular structure formed by winding a magnetic conductive plate, the annular structure is divided into multiple layers in the radial direction, and insulation paste is filled between the layers. One end of the auxiliary back iron is connected with the main back iron, and the other end is connected with the permanent magnet. According to the rotor structure provided by the utility model, the supporting strength is ensured through the main back iron, the auxiliary back iron formed by multi-layer winding is adopted to conduct magnetism on the permanent magnet, and eddy current loss and harmonic loss are reduced through the multi-layer structure, so that the heating of the permanent magnet is remarkably reduced, and the conditions of high motor loss and permanent magnet demagnetization are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a rotor structure and an axial flux motor. Background Art

[0002] The permanent magnets on the rotor of the axial flux motor directly form a magnetic circuit through the solid back iron, and strong eddy current losses and harmonic losses will be generated in the solid back iron. At the same time, eddy current losses and harmonic losses will also exist in the magnets, which will cause the permanent magnets to heat up and even demagnetize due to the heat, causing the motor to be scrapped. Utility Model Content

[0003] The utility model aims to provide a rotor structure and an axial flux motor to solve the problems of high eddy current loss and harmonic loss of the existing rotor and heating of the permanent magnet.

[0004] In order to solve the above technical problems, the technical solution provided by the utility model is:

[0005] A rotor structure includes a main back iron, a secondary back iron and a permanent magnet;

[0006] The secondary back iron is configured as an annular structure wound by a magnetic conductive plate, and the annular structure is divided into multiple layers along the radial direction, and insulating glue is filled between the layers;

[0007] One side of the auxiliary back iron is connected to the main back iron, and the other side is connected to the permanent magnet.

[0008] Furthermore, the permanent magnet is divided into multiple layers along the radial direction of the auxiliary back iron, and insulating glue is filled between the layers.

[0009] Furthermore, the rotor structure also includes a positioning plate, which is arranged on a side of the permanent magnet away from the auxiliary back iron and connected to the main back iron, and a side of the auxiliary back iron away from the permanent magnet is connected to the main back iron;

[0010] The positioning plate is provided with a positioning groove, and the permanent magnet is clamped in the positioning groove.

[0011] Furthermore, the insulating adhesive is a two-component epoxy resin adhesive.

[0012] Furthermore, the plurality of permanent magnets are evenly distributed around the axis of the secondary back iron.

[0013] Furthermore, the material of the magnetic conductive plate is nanocrystalline material or silicon steel material.

[0014] Another aspect of the present invention provides an axial flux motor, comprising the above-mentioned rotor structure.

[0015] Furthermore, the axial flux motor further comprises a shaft unit, and the two rotor structures are sleeved on the shaft unit;

[0016] The shaft unit comprises a power output shaft and a bearing cylinder, the bearing cylinder is sleeved on the power output shaft, and two ends of the bearing cylinder are respectively connected to the two main back irons.

[0017] Furthermore, the shaft unit further comprises a side plate, the side plate is sleeved on the power output shaft and connected to the power output shaft;

[0018] The side plate is connected to the main back iron.

[0019] Furthermore, the axial flux motor also includes a stator assembly, and the stator assembly is arranged between the two rotor structures.

[0020] Based on the above technical solutions, the technical effects that can be achieved by the utility model are:

[0021] The rotor structure provided by the utility model comprises a main back iron, a secondary back iron and a permanent magnet; the secondary back iron is arranged as an annular structure wound by a magnetic conductive plate, the annular structure is divided into multiple layers along the radial direction, and insulating glue is filled between the layers; one end of the secondary back iron is connected to the main back iron, and the other end is connected to the permanent magnet.

[0022] The rotor structure provided by the utility model ensures the supporting strength through the main back iron, adopts the auxiliary back iron formed by multi-layer winding to conduct magnetism to the permanent magnet, and reduces eddy current loss and harmonic loss through its multi-layer structure, thereby significantly reducing the heating of the permanent magnet and avoiding high motor loss and demagnetization of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of a rotor structure provided in an embodiment of the utility model;

[0025] Figure 2 A three-dimensional diagram of a rotor structure provided by an embodiment of the utility model;

[0026] Figure 3 This is a schematic diagram of the structure of the main back iron;

[0027] Figure 4 is a schematic diagram of the structure of a permanent magnet;

[0028] Figure 5 It is a structural schematic diagram of the positioning plate;

[0029] Figure 6 It is a schematic diagram of the structure of the secondary back iron;

[0030] Figure 7 A schematic diagram of the structure of an axial flux motor provided by an embodiment of the utility model;

[0031] Figure 8 A schematic cross-sectional view of an axial flux motor provided by an embodiment of the utility model;

[0032] Fig. 9 A cross-sectional schematic diagram of the shaft unit.

[0033] Icon: 100-rotor structure; 110-main back iron; 120-auxiliary back iron; 130-permanent magnet; 140-positioning plate; 111-annular groove; 141-positioning groove; 200-shaft unit; 210-power output shaft; 220-load-bearing cylinder; 230-side plate. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0037] The permanent magnets on the rotor of the axial flux motor form a magnetic circuit directly through the solid back iron, which causes strong eddy current loss and harmonic loss in the solid back iron. At the same time, eddy current loss and harmonic loss also exist in the permanent magnets, which causes the permanent magnets to heat up and even demagnetize due to the heat, causing the motor to be scrapped.

[0038] In view of this, the utility model provides a rotor structure, including a main back iron 110, a secondary back iron 120 and a permanent magnet 130; the secondary back iron 120 is configured as an annular structure wound by a magnetic conductive plate, and the annular structure is divided into multiple layers along the radial direction, and insulating glue is filled between the layers; one side of the secondary back iron 120 is connected to the main back iron 110, and the other side is connected to the permanent magnet 130.

[0039] The rotor structure 100 provided by the utility model ensures the supporting strength through the main back iron 110, adopts the auxiliary back iron 120 formed by multi-layer winding to conduct magnetism to the permanent magnet 130, and reduces eddy current loss and harmonic loss through its multi-layer structure, thereby significantly reducing the heat generation of the permanent magnet 130 and avoiding high motor loss and demagnetization of the permanent magnet 130.

[0040] The following combination Figure 1-Figure 6 The rotor structure 100 provided in this embodiment is described in detail:

[0041] In the optional solution provided in this embodiment, the rotor structure 100 includes a main back iron 110, a secondary back iron 120, a permanent magnet 130 and a positioning plate 140. Figure 1 , Figure 2 One side of the secondary back iron 120 is connected to the main back iron 110 , and the other side is connected to the permanent magnet 130 . The plurality of permanent magnets 130 are evenly distributed around the axis of the secondary back iron 120 . The positioning plate 140 is arranged on the side of the permanent magnet 130 away from the secondary back iron 120 and connected to the main back iron 110 .

[0042] Specifically, the main back iron 110 is provided with an annular groove 111. Figure 3 As shown, the positioning plate 140 is connected to the main back iron 110 so as to close the annular groove 111 to form a receiving space for fixing the auxiliary back iron 120 and the permanent magnet 130. The permanent magnet 130 is arranged between the auxiliary back iron 120 and the positioning plate 140, and the positioning plate 140 is provided with positioning grooves 141 evenly distributed around its own axis. Figure 5 The permanent magnets 130 are clamped in the positioning slots 141 to fix the positions of the permanent magnets 130 , keep the permanent magnets 130 stably and reliably evenly distributed, and avoid contact between adjacent permanent magnets 130 .

[0043] In this embodiment, the secondary back iron 120 is configured as an annular structure wound by a magnetic conductive plate, and the annular structure is divided into multiple layers along the radial direction, and insulating glue is filled between the layers, such as Figure 6 In short, the shape of the secondary back iron 120 is a spiral line, and the same shape includes a coil spring, a disc mosquito coil, etc. The insulation between the layers and the fixation of the annular structure of the secondary back iron 120 are achieved by insulating glue, so as to achieve a compact layer structure to reduce eddy current loss and harmonic loss by reducing thickness, and at the same time increase the resistance value to reduce the induced current.

[0044] In this embodiment, the magnetic conductive plate is made of a material with ultra-high magnetic permeability, specifically, silicon steel material can be selected, and nanocrystalline material can also be selected, so as to ensure that the auxiliary back iron 120 has good magnetic conductivity and suppress the generation of eddy currents. The insulating glue uses a two-component epoxy resin glue. The main back iron 110 can be made of steel, such as No. 45 steel, so as to obtain good processing accuracy and support strength, and prevent bending deformation caused by the pull of the rotor on the permanent magnet 130. Through the combined use of the main back iron 110 and the auxiliary back iron 120, the support strength of the rotor structure 100 is guaranteed, and the generation of eddy currents is effectively suppressed.

[0045] In this embodiment, the positioning plate 140 is made of non-metallic materials such as glass fiber board, carbon fiber reinforced plastic, glass fiber reinforced plastic, glass fiber reinforced PEEK, etc., to ensure the limiting strength of the permanent magnet 130 and avoid the generation of induced current. Figure 5 As shown, arcs are arranged at the four corners of the positioning groove 141 , and the sharp corners are removed by milling a circular hole, so as to facilitate the installation of the permanent magnet 130 .

[0046] In an optional solution of this embodiment, the permanent magnet 130 is divided into multiple layers along the radial direction of the secondary back iron 120, and insulating glue is filled between the layers, such as Figure 4 As shown. The permanent magnet 130 supported by a multi-layer structure can reduce eddy current loss and harmonic loss. The insulating glue can also use a two-component epoxy resin glue to achieve bonding and insulation between layers. Preferably, the number of layers of the permanent magnet 130 is the same as the number of layers of the auxiliary back iron 120 and corresponds one to one to avoid the situation where the two are connected to each other and the insulating layer loses its function. That is, it is avoided that two adjacent layers of the auxiliary back iron 120 are connected to one layer of the permanent magnet 130 at the same time, thereby causing the two adjacent layers of the auxiliary back iron 120 to be connected.

[0047] In the optional solution of this embodiment, the permanent magnet 130 is made of rare earth permanent magnet material. Since the rare earth permanent magnet material has low internal resistance, significant eddy current loss will be generated when the motor is running. The multi-layer permanent magnet 130 composed of dozens of permanent magnet 130 sheets bonded by insulating adhesive can block the formation of eddy current to reduce loss and reduce the temperature of the permanent magnet 130 to avoid high temperature demagnetization.

[0048] In the optional scheme of this embodiment, the permanent magnet 130 can be set to a fan shape or a trapezoidal shape, and the shape is adjusted to increase the speed of the motor when it resonates, prevent the motor from shaking and resonant whistling noise in the working state, and keep the motor running stably. In this embodiment, by designing the shape of the permanent magnet 130, the speed of the motor resonating is above 2000 rpm, while the motor usually has a speed of less than 1500 rpm.

[0049] The various losses of the rotor structure of this embodiment are reduced to a negligible level, making the motor more energy-efficient and efficient, with a power saving rate of up to 30%-80%.

[0050] Based on the rotor structure 100 provided in this embodiment, an axial flux motor is proposed, including the above-mentioned rotor structure 100, and also including a stator assembly and an axis unit 200. Figure 7-Figure 9 The structure and shape of the axial flux motor provided in this embodiment are described in detail:

[0051] In an optional solution of this embodiment, the axial flux motor includes two symmetrically arranged rotor structures 100, the rotor structure 100 is sleeved on the shaft unit 200 to drive the shaft unit 200 to rotate, and the stator assembly is coaxial with the rotor structure 100 and sleeved on the shaft unit 200. Specifically, the stator assembly is arranged between the two rotor structures 100 and keeps the same distance from the two rotor structures 100 to balance the forces and ensure stable operation of the motor. Figure 7 , Figure 8 Specifically, the magnetic poles of the permanent magnets 130 of the two rotor structures 100 at the same angle are in opposite directions, so as to ensure that the pulling forces of the stator core on the two rotor structures 100 are equal in magnitude and opposite in direction, thereby ensuring the stability of the motor operation.

[0052] Specifically, the shaft unit 200 includes a power output shaft 210, a bearing cylinder 220 and a side plate 230. Fig. 9 As shown. Among them, the bearing cylinder 220 is mounted on the power output shaft 210, and the two ends of the bearing cylinder 220 are respectively connected to the two main back irons 110, and the side plate 230 is mounted on the power output shaft 210 and connected to the power output shaft 210, and the side plate 230 is connected to the main back iron 110 to form a whole. That is, the power output shaft 210 is connected to the main back iron 110 through the side plate 230, so that the rotor structure 100 can drive the power output shaft 210 to rotate around its own axis; the bearing cylinder 220 is connected through the main back iron 110 of the two rotor structures 100 to fix and support the main back iron 110, thereby reducing the force arm when the permanent magnet 130 is subjected to the tension of the stator assembly, and avoiding the main back iron 110 from bending and deforming due to excessive bending moment.

[0053] In addition, the bearing cylinder 220 is mounted on the side plate 230 , and the side plate 230 is an annular structure. The inner wall of the bearing cylinder 220 contacts the outer wall of the side plate 230 so that the bearing cylinder 220 obtains support from the side plate 230 , thereby providing more reliable support for the main back iron 110 .

[0054] Existing axial flux motors are designed for extremely low power, because as the power increases, the motor diameter will increase accordingly, and the rotor diameter will also increase accordingly, which will cause the outer circle of the motor shaft to be farther away from the inner circle formed by the permanent magnet 130, and the distance from the rotor axis to the permanent magnet 130 will increase. This situation will cause the permanent magnet 130 to be easily attracted to the stator core when assembling the motor, causing the rotor back iron to bend and deform locally and be difficult to disassemble. Even if it is barely assembled, the air gap of the motor needs to be increased. In short, high-power axial flux motors are extremely difficult to assemble, and even if they are barely assembled, they are difficult to operate stably and have extremely low efficiency, which makes it difficult for axial flux motors to be widely used.

[0055] The axial flux motor provided in this embodiment forms a stepped shaft with a large diameter in the middle section through the shaft unit 200 composed of the power output shaft 210, the bearing cylinder 220 and the side plate 230, and the section with a large diameter is a hollow shaft, that is, the annular space surrounded by the bearing cylinder 220 and the power output shaft 210. This structure not only ensures that the two ends of the shaft unit 200 are supported by small diameter bearings, but also shortens the force arm of the stator core to attract the permanent magnet 130, avoiding the main back iron 110 from bending and deforming to cause damage to the motor, and at the same time avoids the problem of increasing the moment of inertia of the rotor structure 100 and reducing the efficiency of the motor due to simply increasing the thickness of the back iron.

[0056] In short, the hollow stepped shaft of this embodiment shortens the distance between the permanent magnet 130 and the outer circle of the shaft unit 200 and the tensile force arm of the permanent magnet 130 by supporting the rotor structure 100 with the large-diameter bearing cylinder 220, avoids resisting the bending moment by increasing the thickness of the main back iron 110, ensures the strength of the rotor structure 100 and avoids the increase of the moment of inertia; and reduces the moment of inertia of the motor through the hollow shaft design, so that the axial flux motor can achieve high power.

[0057] In this embodiment, the design of the hollow shaft not only ensures the strength of the shaft unit 200, but also helps to reduce the moment of inertia and the heat dissipation of the shaft center.

[0058] In an optional solution of this embodiment, the shaft unit 200 can be made of a hollow shaft made of an alloy with good fatigue resistance, and two thin hollow shafts are riveted and welded at both ends of the hollow shaft. That is, three sections of hollow shafts are welded, and the middle section is a large diameter section. The alloy can be made of titanium alloy, aluminum alloy and other materials.

[0059] Since the permanent magnet 130 is close to the outer circle of the shaft unit 200, the axial flux motor provided in this embodiment will not have the main back iron 110 bent, causing the permanent magnet 130 to be attracted to the stator core and difficult to separate. Therefore, the air gap can be designed to be smaller to improve the efficiency of the motor, and the main back iron 110 will not be bent, causing the stator assembly and the rotor structure 100 to be attracted together, ensuring the normal operation of the high-power axial flux motor.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A rotor structure, characterized in that: It comprises a main back iron (110), a secondary back iron (120) and a permanent magnet (130); The secondary back iron (120) is configured as an annular structure formed by winding a magnetic conductive plate, and the annular structure is divided into multiple layers along the radial direction, and insulating glue is filled between the layers; One side of the auxiliary back iron (120) is connected to the main back iron (110), and the other side is connected to the permanent magnet (130).

2. The rotor structure according to claim 1, characterized in that: The permanent magnet (130) is divided into multiple layers along the radial direction of the auxiliary back iron (120), and insulating glue is filled between the layers.

3. The rotor structure according to claim 2, characterized in that: It also includes a positioning plate (140), the positioning plate (140) being arranged on a side of the permanent magnet (130) away from the auxiliary back iron (120) and connected to the main back iron (110), and the side of the auxiliary back iron (120) away from the permanent magnet (130) is connected to the main back iron (110); The positioning plate (140) is provided with a positioning groove (141), and the permanent magnet (130) is clamped in the positioning groove (141).

4. The rotor structure according to claim 2, characterized in that: The insulating adhesive is a two-component epoxy resin adhesive.

5. The rotor structure according to claim 1, characterized in that: The plurality of permanent magnets (130) are evenly distributed around the axis of the secondary back iron (120).

6. The rotor structure according to claim 1, characterized in that: The material of the magnetic conductive plate is nanocrystalline material or silicon steel material.

7. An axial flux motor, characterized in that: Comprising the rotor structure (100) according to any one of claims 1 to 6.

8. The axial flux motor according to claim 7, characterized in that: It also includes a shaft unit (200), and the two rotor structures (100) are sleeved on the shaft unit (200); The shaft unit (200) comprises a power output shaft (210) and a bearing cylinder (220), wherein the bearing cylinder (220) is sleeved on the power output shaft (210), and two ends of the bearing cylinder (220) are respectively connected to the two main back irons (110).

9. The axial flux motor according to claim 8, characterized in that: The shaft unit (200) further comprises a side plate (230), wherein the side plate (230) is sleeved on the power output shaft (210) and connected to the power output shaft (210); The side plate (230) is connected to the main back iron (110).

10. The axial flux motor according to claim 7, characterized in that: It also comprises a stator assembly, wherein the stator assembly is arranged between the two rotor structures (100).

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