Rotor structure for high torque density axial flux electric machines

Abstract

The application provides a rotor structure of a high-torque-density axial flux motor, comprising two housings, the interiors of the two housings are jointly provided with a rotor assembly; the rotor assembly comprises two rotor discs, a limiting column, a connecting ring, main magnetic steel, a guide column, reinforced magnetic steel, a through hole, a limiting disc, a pressing plate, a rotor shaft and an embedded slot; the rotor shaft is located in the interiors of the two rotor discs. When the rotor structure is disassembled, the limiting nut is disassembled, the two rotor discs and the connecting ring are separated, the locking nut is disassembled, the limiting disc and the rotor disc are separated, and then the maintenance personnel can conveniently maintain the rotor structure; compared with the prior art, the rotor structure is designed to be detachable, on the one hand, the overall quality of the rotor structure is reduced, and the response speed of the rotor structure is improved, on the other hand, when the rotor structure fails, the maintenance personnel can quickly disassemble the rotor structure, and the maintenance difficulty and cost are reduced.

Description

TECHNICAL FIELD

[0001] The application relates to a rotor structure, in particular a rotor structure of a high-torque-density axial flux motor, and belongs to the technical field of axial flux motors. BACKGROUND

[0002] The high-torque-density axial flux motor refers to an axial flux motor capable of generating a relatively high output torque in a unit volume or unit mass. Similar to ordinary axial flux motors, the high-torque-density axial flux motor works on the principle of electromagnetic induction. An alternating magnetic field is generated by passing alternating current through the stator winding, and the permanent magnet or winding on the rotor is subjected to electromagnetic force under the action of the magnetic field, thereby generating torque to drive the rotor to rotate. The unique feature is that through optimization design, the motor can generate greater electromagnetic force under the same size and weight, thereby achieving higher torque output. Unlike traditional radial flux motors, the magnetic flux direction is parallel to the motor shaft, and the stator and rotor are usually in a disc-shaped structure, which makes the magnetic field distribution more uniform and can effectively utilize space to improve torque density. High remanence and high coercivity permanent magnet materials such as neodymium iron boron permanent magnets are generally used to enhance the magnetic field strength and improve the electromagnetic conversion efficiency of the motor, thereby generating greater torque.

[0003] The stator winding of the axial flux motor usually adopts a multi-phase winding structure, such as a three-phase or multi-phase winding. By reasonably designing the number of turns, wire diameter and winding distribution of the winding, the filling factor and electromagnetic utilization rate of the winding are improved, and the output torque of the motor is increased. In order to achieve high torque density, the mechanical structure of the motor is designed to be compact, high-strength materials and advanced manufacturing processes are used to reduce the volume and weight of the motor while ensuring the mechanical strength of the motor.

[0004] At present, the rotor structure of most axial flux motors on the market adopts an integrated design. This structure has high structural strength due to the overall forming process, which can effectively resist the dual action of centrifugal force and electromagnetic force during high-speed operation of the motor, ensuring the stability of the motor operation. However, the limitations of the integrated structure are also very significant: on the one hand, in order to meet the strength requirements, a large amount of material is often used, resulting in a high overall weight of the rotor, which not only increases the moment of inertia of the motor itself, but also reduces the response speed; on the other hand, this integrated forming method tightly combines the components of the rotor, making it difficult for maintenance personnel to disassemble and replace specific components once there are problems such as internal permanent magnet demagnetization, winding failure or local structural damage. The entire rotor often needs to be disassembled from the motor, and even may need to be returned to the factory for processing, greatly increasing the difficulty and cost of maintenance, prolonging the downtime for maintenance, and reducing the efficiency of equipment use. Therefore, a rotor structure for a high-torque-density axial flux motor is proposed. SUMMARY

[0005] Therefore, the application provides a rotor structure of a high-torque-density axial flux motor to solve or alleviate the technical problems in the prior art and at least provide an advantageous alternative.

[0006] The technical scheme of the embodiment of the application is as follows: the rotor structure of the high-torque-density axial flux motor comprises two housings, and the interiors of the two housings are jointly provided with a rotor assembly;

[0007] The rotor assembly comprises two rotor discs, a limiting column, a connecting ring, main magnetic steel, a guide column, reinforced magnetic steel, a through hole, a limiting disc, a pressing plate, a rotor shaft and an embedded slot.

[0008] The rotor shaft is located in the interiors of the two rotor discs, the opposite faces of the two rotor discs are each provided with a groove, the limiting column is fixedly connected to the two sides of the connecting ring in a symmetrical manner, the through hole is provided in the interior of the rotor disc and penetrates through the groove, the guide column is fixedly connected to the opposite faces of the two rotor discs in a symmetrical manner, the pressing plate is fixedly connected to the outer side wall of the limiting disc in a symmetrical manner, the embedded slot is provided in the outer side wall of the rotor disc in a symmetrical manner, the main magnetic steel is bonded to the opposite faces of the two rotor discs in a symmetrical manner, and the reinforced magnetic steel is embedded in the interior of the embedded slot.

[0009] Further preferably, the connecting ring is inserted into the interiors of the two grooves, the limiting column is inserted into the interior of the through hole, the outer side wall of the limiting column is threadedly connected with a limiting nut, and the limiting nut is attached to the outer side wall of the rotor disc.

[0010] Further preferably, the limiting disc is slidingly connected to the outer side wall of the guide column, the outer side wall of the guide column is threadedly connected with a locking nut, and the locking nut is attached to the outer side wall of the limiting disc.

[0011] Further preferably, the pressing plate is attached to the outer side wall of the reinforced magnetic steel, and the reinforced magnetic steel and the main magnetic steel are staggered.

[0012] Further preferably, the rotor assembly further comprises a limiting slot, a connecting seat, a positioning hole, a limiting block, two pressing plates, a positioning column, a stop block, a spring and a fixing ring.

[0013] The limiting slot is provided in the inner side wall of the rotor disc, the connecting seat is fixedly connected to the outer side wall of the rotor shaft, the positioning hole is provided in the interior of the connecting seat, the positioning column is fixedly connected to the opposite faces of the two pressing plates in a symmetrical manner, the spring and the pressing plate are both sleeved on the exterior of the rotor shaft, the fixing ring is fixedly connected to the outer side wall of the rotor shaft, the stop block is fixedly connected to the outer side wall of the pressing plate in a symmetrical manner, and the limiting block is fixedly connected to the outer side wall of the connecting seat in a symmetrical manner.

[0014] Further preferably, the opposite surfaces of the two pressing plates are attached to the outer side wall of the connecting seat, and the positioning column is inserted into the inside of the positioning hole.

[0015] Further preferably, the pressing plate is slidingly and rotatably connected to the outer side wall of the rotor shaft, one end of the spring abuts against one side of the pressing plate away from the connecting seat, and the other end of the spring abuts against the outer side wall of the fixed ring.

[0016] Further preferably, the limiting block is slidingly connected to the inner side wall of the limiting groove, and the stopper is attached to the outer side wall of the rotor disc.

[0017] Further preferably, the inner side walls of the two machine housings are both provided with stator cores, the inside of the stator core is wound with a stator winding, and the two machine housings are fixedly connected through connecting bolts.

[0018] Further preferably, the rotor disc is located between the two stator cores, and the rotor shaft is rotatably connected to the inside of the two machine housings through two bearings.

[0019] The embodiment of the present application has the following advantages due to the adoption of the above technical solutions.

[0020] When the rotor structure is disassembled, the pressing plate is pulled, the pressing plate drives the positioning column to be separated from the positioning hole, then the pressing plate is rotated, the pressing plate drives the stopper to correspond to the limiting block, at this time, the position limitation of the rotor disc is released, the rotor disc and the connecting seat can be separated, then the limiting nut is disassembled, the two rotor discs and the connecting ring can be separated, the locking nut is disassembled, the limiting disc and the rotor disc can be separated, and then the maintenance personnel can conveniently maintain the rotor structure; compared with the prior art, the rotor structure of the present application is designed to be detachable, on the one hand, the overall quality of the rotor structure is reduced, and the response speed of the rotor structure is improved, on the other hand, when the rotor structure fails, the maintenance personnel can quickly disassemble the rotor structure, and the maintenance difficulty and cost are reduced.

[0021] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features will become apparent to those skilled in the art from the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0023] Figure 1 Structure diagram of the rotor structure of the high-torque-density axial flux motor of the present application;

[0024] Figure 2 Structure exploded view of the present application;

[0025] Figure 3 Structure diagram of the rotor assembly of the present application;

[0026] Figure 4 Structure exploded view of the rotor assembly of the present application;

[0027] Figure 5 Structure diagram of the connecting ring of the present application;

[0028] Figure 6 Structure diagram of the limiting disc of the present application;

[0029] Figure 7 Structure diagram of the connecting seat of the present application;

[0030] Figure 8 Structure diagram of the pressing disc of the present application.

[0031] Reference signs: 101, rotor assembly; 11, rotor disc; 12, groove; 13, limiting groove; 14, limiting column; 15, connecting ring; 16, main magnetic steel; 17, guide column; 18, enhanced magnetic steel; 19, through hole; 20, limiting disc; 21, pressing plate; 22, locking nut; 23, limiting nut; 24, rotor shaft; 25, embedded groove; 26, connecting seat; 27, positioning hole; 28, limiting block; 29, pressing disc; 30, positioning column; 31, stop block; 32, spring; 33, fixing ring; 41, machine shell; 43, stator core; 44, stator winding. DETAILED DESCRIPTION

[0032] In the following, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0033] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0034] In the prior art, the rotor structure of most axial flux motors on the market adopts an integrated design. This structure, thanks to the process characteristics of integral forming, gives the rotor high structural strength, effectively resists the dual action of centrifugal force and electromagnetic force during high-speed operation of the motor, and ensures the stability of the motor operation. However, the limitations of the integrated structure are also very significant: on the one hand, in order to meet the strength requirements, a large amount of material is often used, resulting in a high overall weight of the rotor, which not only increases the moment of inertia of the motor itself, but also reduces the response speed; on the other hand, this integrated forming method tightly combines the various components of the rotor, making it difficult for maintenance personnel to disassemble and replace specific components once there are problems such as internal permanent magnet demagnetization, winding failure, or local structural damage. The entire rotor often needs to be disassembled from the motor, and even may need to be returned to the factory for processing, greatly increasing the difficulty and cost of maintenance, prolonging the downtime for repair, and reducing the efficiency of equipment use;

[0035] Therefore, referring to Figures 1-8 The rotor structure of the high-torque-density axial flux motor provided by the embodiments of the present application includes two housings 41, and the interiors of the two housings 41 are jointly provided with a rotor assembly 101.

[0036] The rotor assembly 101 includes two rotor discs 11, a limiting column 14, a connecting ring 15, main magnetic steel 16, a guide column 17, enhanced magnetic steel 18, a through hole 19, a limiting disc 20, a pressing plate 21, a rotor shaft 24, and an embedded slot 25.

[0037] The rotor shaft 24 is located in the interiors of the two rotor discs 11, the opposite faces of the two rotor discs 11 are each provided with a groove 12, the limiting column 14 is symmetrically and fixedly connected to the two sides of the connecting ring 15, the through hole 19 is provided in the interior of the rotor disc 11 and penetrates the groove 12, the connecting ring 15 is inserted into the interiors of the two grooves 12, the limiting column 14 is inserted into the interior of the through hole 19, the outer side wall of the limiting column 14 is threadedly connected with a limiting nut 23, and the limiting nut 23 is attached to the outer side wall of the rotor disc 11. The position of the connecting ring 15 can be limited through the groove 12, the position of the limiting column 14 can be limited through the through hole 19, and the position of the limiting column 14 can be limited through the limiting nut 23, so that the two rotor discs 11 can be fixedly connected.

[0038] When the rotor disc 11 is disassembled, only the limiting nut 23 needs to be disassembled, so that the two rotor discs 11 and the connecting ring 15 can be separated.

[0039] The guide column 17 is symmetrically fixedly connected to the opposite faces of the two rotor discs 11, the pressing plate 21 is symmetrically fixedly connected to the outer side wall of the limiting disc 20, the limiting disc 20 is slidingly connected to the outer side wall of the guide column 17, the outer side wall of the guide column 17 is threadedly connected with the locking nut 22, the locking nut 22 is attached to the outer side wall of the limiting disc 20, the limiting disc 20 is provided with a hole corresponding to the guide column 17, so as to be mounted on the guide column 17, and the position of the limiting disc 20 can be limited through cooperation of the guide column 17 and the locking nut 22;

[0040] The embedding groove 25 is symmetrically formed in the outer side wall of the rotor disc 11, the main magnetic steel 16 is symmetrically bonded to the opposite faces of the two rotor discs 11, and the reinforcing magnetic steel 18 is embedded in the embedding groove 25, the position of the reinforcing magnetic steel 18 can be limited through the pressing plate 21 when the position of the limiting disc 20 is fixed, thereby enhancing the stability of the structure;

[0041] The reinforcing magnetic steel 18 is staggered with the main magnetic steel 16, and the interaction of the magnetic field and the magnetic flux can be enhanced by arranging the reinforcing magnetic steel 18 between the adjacent main magnetic steels 16;

[0042] The interaction of the magnetic field is that the torque of the motor is generated by the interaction of the magnetic field generated by the stator winding 44 and the magnetic field of the magnetic steel on the rotor, and the rotor magnetic field strength is enhanced by increasing the number of magnetic steels, more magnetic steels interact with the stator magnetic field, thereby generating greater electromagnetic force, according to the torque being equal to the force multiplied by the force arm, the electromagnetic force is increased, and the torque is also correspondingly improved, thereby achieving the purpose of improving the torque;

[0043] The magnetic flux is increased by increasing the number of magnetic steels, and the magnetic flux through the air gap of the motor is increased, according to the principle of motor, the electromagnetic torque is proportional to the product of the magnetic flux and the stator current, in the case that the stator current is constant, the magnetic flux is increased, and the torque of the motor is also increased.

[0044] In order to solve the problems in the prior art, the rotor structure of the high-torque-density axial flux motor is provided in the embodiments of the present application, and the problems are solved through the above technical solutions:

[0045] The two rotor discs 11 are connected and fixed through the connecting ring 15, the limiting column 14 and the limiting nut 23, so that a hollow structure is formed in the rotor, the weight of the rotor as a whole is reduced, and when the rotor structure needs to be disassembled and maintained, the limiting nut 23 is disassembled, the two rotor discs 11 and the connecting ring 15 are separated, the locking nut 22 is disassembled, and the limiting disc 20 and the rotor disc 11 are separated, thereby facilitating maintenance personnel to maintain the rotor structure;

[0046] Compared with the prior art, the rotor structure of the application reduces the overall mass of the rotor structure, improves the response speed of the rotor structure, and when the rotor structure fails, maintenance personnel can quickly disassemble the rotor structure, thereby reducing the maintenance difficulty and cost.

[0047] In one embodiment, the enhanced magnetic steel 18 is arranged at a distance from the main magnetic steel 16, and the distance is calculated by a distance calculation method.

[0048] The specific steps of the distance calculation method include:

[0049] I. Determine the basic parameters of the motor

[0050] Before calculating the distance between the magnetic steels, the following motor design parameters need to be determined:

[0051] Rated power and speed: determine the torque demand of the motor.

[0052] The number of pole pairs and the air gap length: affect the magnetic circuit design and magnetic field distribution.

[0053] The diameter and thickness of the rotor disc: limit the size and layout space of the magnetic steel.

[0054] The performance of the permanent magnet material: such as residual magnetism, coercive force, etc., affects the magnetic field strength of the magnetic steel.

[0055] II. Main magnetic steel layout design

[0056] The main magnetic steel is the main source of the rotor disc magnetic field, and its layout needs to meet the following requirements:

[0057] Polarity distribution: the main magnetic steel is usually arranged alternately according to N-S polarity to form the basic magnetic polarity distribution.

[0058] Number determination: according to the number of pole pairs and the size of the rotor disc, the number of main magnetic steels is determined. For example, for a 4-pole motor, 4 main magnetic steels (2 pairs of N-S poles) need to be arranged on the rotor disc.

[0059] Preliminary distance estimation: the distance between the main magnetic steels needs to ensure that the magnetic fields of adjacent magnetic steels do not interfere significantly. When preliminarily estimating, the following principles can be referred to:

[0060] The arc length (or axial length) of the main magnetic steel should account for 1 / pole pair number of the circumference of the rotor disc.

[0061] The distance between adjacent main magnetic steels should be greater than 1.5 times the thickness of the magnetic steel to avoid local saturation caused by magnetic field superposition.

[0062] III. Role and layout of enhanced magnetic steel

[0063] The enhanced magnetic steel is used to supplement the magnetic field of the main magnetic steel to improve the air gap flux density and torque output. Its layout needs to consider the following factors:

[0064] Position Selection: Enhancement magnets are usually arranged between the main magnets, close to the air gap side, to directly enhance the air gap magnetic field.

[0065] Quantity Determination: The number of enhancement magnets depends on the spacing of the main magnets and the magnetic field enhancement requirements. Generally, 1-2 enhancement magnets can be arranged in each main magnet interval.

[0066] Spacing Design: The spacing of the enhancement magnets and the main magnets needs to meet the following conditions:

[0067] Avoid Magnetic Field Interference: The magnetic field of the enhancement magnets should work synergistically with the magnetic field of the main magnets, rather than canceling each other out.

[0068] Mechanical Strength Requirements: The fixation of the enhancement magnets needs to consider the mechanical strength of the rotor disc to avoid structural weakness due to too small spacing.

[0069] Four, Magnetic Field Simulation and Optimization

[0070] Since the calculation of the magnetic steel spacing involves complex magnetic field distribution, it needs to be optimized through electromagnetic simulation software (including ANSYS Maxwell, JMAG). The specific steps are as follows:

[0071] Model Establishment: According to the motor parameters and magnetic steel layout, a three-dimensional electromagnetic model is established.

[0072] Parameterized Scanning: Set the spacing of the main magnets and the enhancement magnets as variables and perform parameterized scanning to observe the changes in magnetic field distribution and torque output.

[0073] Optimization Objectives:

[0074] Maximize Air Gap Flux Density: Adjust the spacing to maximize the air gap flux density.

[0075] Minimize Torque Fluctuation: Ensure uniform magnetic field distribution and reduce torque pulsation.

[0076] Meet Mechanical Strength: Consider the stress distribution of the rotor disc during simulation to avoid structural failure due to too small spacing.

[0077] Result Analysis: According to the simulation results, select the optimal magnetic steel spacing combination.

[0078] Five, Specific Steps for Spacing Calculation

[0079] The following are the detailed steps for calculating the magnetic steel spacing, which do not involve formula derivation, but only describe the logical flow:

[0080] Step 1: Determine the preliminary spacing of the main magnets

[0081] According to the rotor disc diameter and the number of pole pairs, calculate the circumferential distribution angle of the main magnets.

[0082] Assuming the arc length of the main magnetic steel is L1, the rotor disc circumference is C, and the number of pole pairs is P, then the number of main magnetic steels N = 2P.

[0083] The initial distance S1 = (C - N × L1) / N (considering the minimum safety distance between magnetic steels).

[0084] Step 2: Evaluate the insertion position of the enhanced magnetic steel

[0085] Insert the enhanced magnetic steel between the main magnetic steels, assuming the arc length of the enhanced magnetic steel is L2.

[0086] The insertion position of the enhanced magnetic steel needs to avoid direct conflict with the magnetic field of the main magnetic steel, usually choosing the area where the main magnetic field is weak.

[0087] Preliminarily determine the distance S2 between the enhanced magnetic steel and the main magnetic steel, which needs to satisfy S2 > L2 / 2 (to avoid magnetic field superposition).

[0088] Step 3: Magnetic field simulation and distance adjustment

[0089] Establish a model in simulation software and set the initial distance of the main magnetic steel and the enhanced magnetic steel.

[0090] Run the simulation and observe the air gap magnetic flux density distribution and torque output.

[0091] If the air gap magnetic flux density distribution is uneven or the torque fluctuation is large, adjust the distance between the main magnetic steel and the enhanced magnetic steel:

[0092] Increase the distance: reduce the magnetic field superposition and reduce the risk of local high magnetic density.

[0093] Reduce the distance: appropriately reduce the distance in the area where the magnetic field is weak to enhance the magnetic field strength.

[0094] Repeat the simulation until the magnetic field distribution and torque output meet the design requirements.

[0095] Step 4: Mechanical strength verification

[0096] Introduce a mechanical stress analysis module in the simulation to check the stress distribution of the rotor disc when rotating at high speed.

[0097] If the stress exceeds the material allowable value, adjust the magnetic steel distance or increase the rotor disc thickness.

[0098] Ensure the reliability of the magnetic steel fixing structure to avoid magnetic steel falling off due to centrifugal force.

[0099] Step 5: Heat dissipation performance evaluation

[0100] Consider the impact of magnetic steel distance on heat dissipation, too small distance may cause local overheating.

[0101] Add a thermal analysis module to the simulation to observe the temperature distribution of the rotor disc.

[0102] If the local temperature is too high, increase the distance between the magnetic steel or increase the heat dissipation channel.

[0103] Step 6: Final distance determination

[0104] Based on the magnetic field distribution, torque output, mechanical strength and heat dissipation performance, determine the final distance of the main magnetic steel and the reinforcing magnetic steel.

[0105] Make a prototype for experimental verification, and make fine adjustments according to the experimental results.

[0106] Six, experimental verification and iterative optimization

[0107] Make a prototype and test its torque output, efficiency and temperature rise and other performance indicators.

[0108] Compare the experimental data with the simulation results and analyze the reasons for the differences.

[0109] Adjust the magnetic steel distance according to the experimental results, and perform iterative optimization until the design requirements are met.

[0110] Seven, experimental verification and fault-tolerant design

[0111] High-precision experimental test platform

[0112] To verify the effectiveness of the magnetic steel distance design, a high-precision experimental platform needs to be built:

[0113] Dynamic torque test system:

[0114] Use high-precision torque sensors (such as HBM T40B) to measure the motor output torque in real time and verify the accuracy of the simulation results.

[0115] Infrared thermal imager:

[0116] Monitor the surface temperature distribution of the rotor disc to evaluate whether the heat dissipation design meets the requirements.

[0117] High-speed camera:

[0118] Capture the deformation of the magnetic steel under high-speed rotation to ensure the safety of the mechanical structure.

[0119] Eight, fault-tolerant design and reliability evaluation

[0120] The motor may face magnetic steel demagnetization, local overheating and other faults in actual operation, and needs to be designed to improve reliability:

[0121] Redundant magnetic steel layout:

[0122] Add standby magnetic steel in key areas and automatically switch to redundant magnetic steel when the main magnetic steel fails.

[0123] Fault diagnosis algorithm:

[0124] Based on motor current, vibration and other signals, real-time monitoring of the state of the magnetic steel and early warning of potential failure.

[0125] Accelerated life test:

[0126] Through extreme conditions such as high temperature, high humidity, high vibration test, to evaluate the long-term reliability of the magnetic steel spacing design.

[0127] Key considerations

[0128] Magnetic steel material properties: Different permanent magnet materials have different residual magnetism and coercive force, and the spacing needs to be adjusted according to the material properties.

[0129] Manufacturing process limitations: The machining and assembly accuracy of the magnetic steel will affect the actual spacing, and the tolerance needs to be reserved in the design.

[0130] Dynamic performance considerations: When the motor is running at high speed, the magnetic steel spacing may change due to centrifugal force, and dynamic stability needs to be considered in the design.

[0131] Multi-physical field coupling: The coupling effect of magnetic field, mechanical field and thermal field needs to be fully considered in simulation to avoid performance degradation caused by single optimization.

[0132] The calculation of the spacing between the main magnetic steel and the reinforcing magnetic steel is the core link of the rotor disc design of the axial magnetic field motor, which needs to be optimized through electromagnetic simulation, mechanical strength analysis and thermal analysis. In the design process, the magnetic field performance, mechanical reliability and heat dissipation demand need to be balanced, and the effectiveness of the design is ensured through experimental verification. In the future, with the development of material science and simulation technology, the optimization of magnetic steel spacing will be more accurate, and the axial magnetic field motor will develop towards higher torque density and efficiency.

[0133] In one embodiment, high-strength non-magnetic material such as titanium alloy or carbon fiber composite is used as the rotor disc substrate to improve mechanical bearing capacity, and the rotor disc structure is designed through topology optimization, such as adding local reinforcement ribs in the magnetic steel mounting area. Dynamic stress analysis is introduced in the simulation to simulate the stress distribution of the motor at maximum speed, ensuring that the magnetic steel spacing is within a safe range;

[0134] Design of heat dissipation channels (such as air gaps or heat-conducting fillers) between magnetic steels to improve heat dissipation efficiency through forced air cooling or liquid cooling, use low-loss permanent magnet materials (such as samarium-cobalt permanent magnets) or surface coating insulation layer to reduce eddy current loss, and couple thermal analysis module in simulation to optimize magnetic steel spacing to balance thermal resistance and magnetic field strength;

[0135] Adopting modular magnetic steel design, reducing processing difficulty through standardized components; introducing 3D printing technology to manufacture rotor disc, realizing rapid forming of complex magnetic steel layout, automatically optimizing magnetic steel spacing through parameterized design tools (such as Isight), reducing manual trial and error cost.

[0136] In one embodiment, the rotor assembly 101 further comprises a limiting groove 13, a connecting seat 26, a positioning hole 27, a limiting block 28, two pressure plates 29, a positioning column 30, a stop block 31, a spring 32 and a fixing ring 33;

[0137] The limiting groove 13 is opened on the inner side wall of the rotor disc 11, the connecting seat 26 is fixedly connected to the outer side wall of the rotor shaft 24, the limiting block 28 is slidingly connected to the inner side wall of the limiting groove 13, the stop block 31 is attached to the outer side wall of the rotor disc 11, and the outer side wall of the connecting seat 26 is attached to the inner side wall of the rotor disc 11. Thus, when the axial flux motor is working, the rotor disc 11 drives the connecting seat 26 to rotate through the limiting block 28, and the connecting seat 26 drives the rotor shaft 24 to rotate, thereby realizing power transmission;

[0138] The positioning hole 27 is opened in the interior of the connecting seat 26, the positioning column 30 is fixedly connected to the opposite faces of the two pressure plates 29, the opposite faces of the two pressure plates 29 are attached to the outer side wall of the connecting seat 26, the positioning column 30 is inserted into the interior of the positioning hole 27, and the stop block 31 is fixedly connected to the outer side wall of the pressure plate 29. Through the cooperation of the positioning hole 27 and the positioning column 30, the position of the pressure plate 29 can be limited. When the rotor shaft 24 rotates, the rotor disc 11 can be prevented from falling off from the connecting seat 26 through the two pressure plates 29, thereby ensuring the stability of the structure;

[0139] The spring 32 and the pressure plate 29 are both sleeved on the exterior of the rotor shaft 24, the fixing ring 33 is fixedly connected to the outer side wall of the rotor shaft 24, the limiting block 28 is fixedly connected to the outer side wall of the connecting seat 26, the pressure plate 29 is slidingly and rotatably connected to the outer side wall of the rotor shaft 24, one end of the spring 32 abuts against one side of the pressure plate 29 away from the connecting seat 26, and the other end of the spring 32 abuts against the outer side wall of the fixing ring 33. Through the spring 32 pushing the pressure plate 29, the position of the pressure plate 29 is fixed, and the position of the rotor disc 11 can be limited. When it is needed to separate the rotor disc 11 from the rotor shaft 24, the pressure plate 29 is pulled, the pressure plate 29 drives the positioning column 30 to be separated from the positioning hole 27, then the pressure plate 29 is rotated, the pressure plate 29 drives the stop block 31 to correspond to the limiting block 28, at this time, the position limitation of the rotor disc 11 is released, and the rotor disc 11 can be separated from the connecting seat 26.

[0140] In one embodiment, the inner side wall of the two housings 41 is provided with a stator core 43, the inside of the stator core 43 is wound with a stator winding 44, the two housings 41 are fixedly connected through connecting bolts, the rotor disc 11 is located between the two stator cores 43, the rotor shaft 24 is rotatably connected to the inside of the two housings 41 through two bearings, when the axial flux motor is controlled to work, the stator winding 44 is energized, at this time, the magnetic field is generated on both sides of the motor rotor and acts on the magnetic steel, the magnetic field interacts with the magnetic field generated by the magnetic steel, torque is generated, the rotor disc 11 of the axial flux motor rotates, the rotor disc 11 drives the rotor shaft 24, and then the power output can be realized.

[0141] In the working process of the present application: the stator winding 44 is energized, at this time, the magnetic field is generated on both sides of the motor rotor and acts on the magnetic steel, the magnetic field interacts with the magnetic field generated by the magnetic steel, torque is generated, the rotor disc 11 of the axial flux motor rotates, the connecting seat 26 is driven to rotate by the limiting block 28, the connecting seat 26 drives the rotor shaft 24 to rotate, so that the power transmission is realized, when the rotor structure is disassembled, the pressing plate 29 is pulled, the positioning column 30 is driven to disengage from the positioning hole 27 by the pressing plate 29, then the pressing plate 29 is rotated, the stop block 31 is driven to correspond to the limiting block 28 by the pressing plate 29, at this time, the position limitation of the rotor disc 11 is released, the rotor disc 11 and the connecting seat 26 can be separated, then the limiting nut 23 is disassembled, the two rotor discs 11 and the connecting ring 15 can be separated, the locking nut 22 is disassembled, the limiting disc 20 and the rotor disc 11 can be separated, and then the maintenance personnel can conveniently maintain the rotor structure;

[0142] Compared with the prior art, the rotor structure of the present application is designed to be detachable, on the one hand, the overall mass of the rotor structure is reduced, and the response speed of the rotor structure is improved, on the other hand, when the rotor structure fails, the maintenance personnel can quickly disassemble the rotor structure, and the maintenance difficulty and cost are reduced.

[0143] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of various changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A rotor structure for a high torque density axial flux electric machine comprising two machine casings (41) characterised in that: The interiors of the two housings (41) are jointly provided with a rotor assembly (101); The rotor assembly (101) comprises two rotor discs (11), limiting columns (14), a connecting ring (15), main magnetic steels (16), guide columns (17), reinforcing magnetic steels (18), through holes (19), limiting discs (20), pressing plates (21), a rotor shaft (24) and embedded grooves (25); The rotor shaft (24) is located in the interiors of the two rotor discs (11), the opposite faces of the two rotor discs (11) are each provided with a groove (12), the limiting columns (14) are fixedly connected in pairs on the two sides of the connecting ring (15), the through holes (19) are formed in the interiors of the rotor discs (11) and penetrate through the grooves (12), the guide columns (17) are fixedly connected in pairs on the opposite faces of the two rotor discs (11), the pressing plates (21) are fixedly connected in pairs on the outer side walls of the limiting discs (20), the pressing plates (21) are attached to the outer side walls of the reinforcing magnetic steels (18), the embedded grooves (25) are symmetrically formed in the outer side walls of the rotor discs (11), the main magnetic steels (16) are symmetrically attached to the opposite faces of the two rotor discs (11), the reinforcing magnetic steels (18) are embedded in the interiors of the embedded grooves (25), and the reinforcing magnetic steels (18) and the main magnetic steels (16) are staggered, The rotor assembly (101) comprises limiting grooves (13), connecting seats (26), positioning holes (27), limiting blocks (28), two pressing plates (29), positioning columns (30), stop blocks (31), springs (32) and fixing rings (33); the limiting grooves (13) are formed in the inner side walls of the rotor discs (11), the connecting seats (26) are fixedly connected to the outer side walls of the rotor shaft (24), the positioning holes (27) are formed in the interiors of the connecting seats (26), the positioning columns (30) are fixedly connected in pairs to the opposite faces of the two pressing plates (29), the springs (32) and the pressing plates (29) are sleeved on the outer portion of the rotor shaft (24), the fixing rings (33) are fixedly connected to the outer side walls of the rotor shaft (24), the stop blocks (31) are fixedly connected in pairs to the outer side walls of the pressing plates (29), and the limiting blocks (28) are fixedly connected in pairs to the outer side walls of the connecting seats (26).

2. The rotor structure of a high torque density axial flux electric machine according to claim 1, characterized in that: The connecting ring (15) is inserted into the interiors of the two grooves (12), the limiting columns (14) are inserted into the interiors of the through holes (19), the outer side walls of the limiting columns (14) are threadedly connected with limiting nuts (23), and the limiting nuts (23) are attached to the outer side walls of the rotor discs (11).

3. The rotor structure of a high torque density axial flux electric machine according to claim 2, characterized in that: The limiting discs (20) are slidingly connected to the outer side walls of the guide columns (17), the outer side walls of the guide columns (17) are threadedly connected with locking nuts (22), and the locking nuts (22) are attached to the outer side walls of the limiting discs (20).

4. The rotor structure of a high torque density axial flux electric machine of claim 1, wherein: The opposite faces of the two pressing plates (29) are attached to the outer side walls of the connecting seats (26), and the positioning columns (30) are inserted into the interiors of the positioning holes (27).

5. The rotor structure of a high torque density axial flux electric machine according to claim 4, characterized in that: The pressing disc (29) is slidingly and rotatably connected to the outer side wall of the rotor shaft (24), one end of the spring (32) abuts against one side of the pressing disc (29) away from the connecting base (26), and the other end of the spring (32) abuts against the outer side wall of the fixed ring (33).

6. The rotor structure of a high torque density axial flux electric machine according to claim 5, characterized in that: The limiting block (28) is slidingly connected to the inner side wall of the limiting groove (13), and the stop block (31) is attached to the outer side wall of the rotor disc (11).

7. The rotor structure of a high torque density axial flux electric machine of claim 1, wherein: The inner side walls of the two machine housings (41) are each provided with a stator core (43), the stator core (43) has a stator winding (44) wound thereon, and the two machine housings (41) are fixedly connected through connecting bolts.

8. The rotor structure of a high torque density axial flux electric machine according to claim 7, characterized in that: The rotor disc (11) is located between the two stator cores (43), and the rotor shaft (24) is rotatably connected to the interiors of the two machine housings (41) through two bearings.

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