Axial flux motor, electric drive system, and vehicle

Abstract

The present application discloses an axial flux motor, an electric drive system, and a vehicle. The axial flux motor adopts a single-stator dual-rotor configuration with a stator centrally arranged and rotors arranged on two sides, and comprises a stator assembly, and a first rotor assembly and a second rotor assembly distributed on two sides of the stator assembly. The first rotor assembly and the second rotor assembly are connected to the stator assembly by means of a first rotor bearing and a second rotor bearing, respectively. Since the single-stator dual-rotor axial flux motor comprises only one stator assembly, energy loss is low and heat generation is low, and thus higher power density and higher energy conversion efficiency are achieved. One end of a rotor shaft is fixedly connected to an output portion of the first rotor assembly and the other end is transmittingly connected to an output portion of the second rotor assembly, and therefore, the tolerances of the relative positions of the two rotor assemblies are smaller, and magnetic poles of magnetic steels of the two rotor assemblies can be in one-to-one correspondence, thereby reducing the difficulty of motor calibration after assembly of a motor assembly.

Description

Axial flux motors, electric drive systems and vehicles

[0001] This application claims priority to Chinese patent application filed on February 28, 2025, with application number 202510236909.5 and entitled "Axial Flux Motor, Electric Drive System and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of motor technology, and in particular relates to an axial flux motor, an electric drive system, and a vehicle. Background Technology

[0003] An axial flux motor (AFM) is a type of motor in which the magnetic field is distributed along the motor's axis, and its operating principle is based on the law of electromagnetic induction. Unlike traditional radial flux motors, the stator and rotor of an axial flux motor have a disc-shaped structure, and the air gap magnetic field is parallel to the motor axis. Compared to traditional motors, axial flux motors use less material and have a simpler structure, resulting in significant advantages such as higher power density, a larger area of ​​high-efficiency region, smaller size, and lighter weight. Axial flux motors offer a significant advantage in axial dimensions; for the same power output, the axial dimension, volume, and weight are reduced by one-third. Due to their flat, compact structure and short axial dimension, axial flux motors are particularly suitable for applications with limited axial dimensions, such as hub motors for electric vehicles, traction machines for elevators, and propulsion motors for silent submarines.

[0004] Axial flux motors can be flexibly configured with multiple rotor and stator layers, thereby improving output performance and meeting diverse application requirements. Typically, axial flux motors are categorized into single-stator single-rotor, single-stator dual-rotor, dual-stator single-rotor, and multi-stator multi-rotor combinations. Different types of axial flux motors exhibit significant differences in manufacturing and assembly difficulty, cooling methods, and application scenarios. The high degree of installation freedom and the more flexible modular design of the stator and rotor assemblies make axial flux motors a future trend in drive motor development.

[0005] Of course, axial flux motors also have some obvious disadvantages, mainly in terms of heat dissipation difficulty and more complex manufacturing and assembly (because the structure of axial flux motors is different from that of radial flux motors, there are significant differences in their assembly, and the assembly scheme of traditional radial flux motors is not applicable to axial flux motors), so mass commercialization is somewhat difficult. Summary of the Invention

[0006] This application aims to address at least one of the technical problems existing in axial flux motors in related technologies. To this end, this application proposes an axial flux motor, an electric drive system, and a vehicle, which has higher working performance and efficiency, and can achieve more stable, reliable, and efficient motor assembly assembly.

[0007] In a first aspect of this application, an axial flux motor is provided, comprising:

[0008] Stator assembly;

[0009] A first rotor assembly is connected to the stator assembly via a first rotor bearing, and the first rotor assembly is located on a first side of the axial direction of the stator assembly;

[0010] The second rotor assembly is connected to the stator assembly via a second rotor bearing, and the second rotor assembly is located on the second side of the axial direction of the stator assembly;

[0011] The rotor shaft passes through the stator assembly and is fixedly connected to the output part of the first rotor assembly. The rotor shaft is also drively connected to the output part of the second rotor assembly. Both the first rotor bearing and the second rotor bearing are mounted on the rotor shaft.

[0012] In some embodiments, the rotor shaft and the output section of the first rotor assembly are integrally formed; the rotor shaft and the output section of the second rotor assembly are keyed together.

[0013] In some embodiments, the rotor shaft includes a first shaft segment, a splined shaft, and a third shaft segment connected in sequence; both the first rotor bearing and the second rotor bearing are interference-fitted with the first shaft segment.

[0014] In some embodiments, the axial flux motor further includes a pressure ring that is interference-fitted with the third shaft segment.

[0015] In some embodiments, both the first rotor assembly and the second rotor assembly include a turntable, a rotor core, a rotor magnet, and a rotor frame arranged sequentially; the turntable is connected to the rotor frame to axially limit the rotor core and the rotor magnet.

[0016] In some embodiments, the rotor magnet comprises a plurality of magnet units arranged in a circumferential array; the magnet units are provided with grooves.

[0017] In some embodiments, the magnet unit includes a plurality of magnetic steel sheets stacked sequentially in a radial direction, with adjacent magnetic steel sheets glued together; the magnetic steel sheets are flat plates or curved plates.

[0018] In some embodiments, the magnet unit has a recess on its side, and the recesses of two adjacent magnet units form a receiving groove, with the rotor frame embedded in the receiving groove and abutting against the bottom wall of the recess.

[0019] In some embodiments, the turntable has an inner cavity, and the inner wall of the turntable is provided with a plurality of first limiting ribs distributed circumferentially, and the inner cavity of the turntable is divided into a plurality of first limiting grooves by the first limiting ribs.

[0020] In some embodiments, the rotor core includes a plurality of soft magnetic sheets arranged in a circumferential array; the plurality of soft magnetic sheets are disposed one-to-one in a plurality of the first limiting grooves; the soft magnetic sheets are glued and fixed to the turntable.

[0021] In some embodiments, the soft magnetic sheet is provided with a second limiting rib, which is staggered from the first limiting rib; two adjacent soft magnetic sheets form a second limiting groove through the second limiting rib.

[0022] In some embodiments, the rotor magnet includes a plurality of magnet units arranged in a circumferential array, and the plurality of magnet units are disposed one-to-one in a plurality of second limiting grooves.

[0023] In some embodiments, the turntable of the first rotor assembly is a first turntable, which is integrally formed with the rotor shaft; the first turntable is provided with a protruding first mounting portion.

[0024] In some embodiments, the turntable of the second rotor assembly is a second turntable, which is splined with the rotor shaft; the second turntable is provided with a protruding second mounting portion.

[0025] In some embodiments, the turntables of the first rotor assembly and the second rotor assembly are provided with outwardly protruding limiting protrusions, which abut against the corresponding first rotor bearing or second rotor bearing.

[0026] In some embodiments, the stator assembly includes an annular stator housing with a stator mounting cavity, a stator bushing, and a stator winding and a stator core located in the stator mounting cavity; the stator winding is wound on the stator core; the stator bushing is fitted into an annular hole in the stator housing; and the first rotor bearing and the second rotor bearing are both located in the stator bushing.

[0027] In some embodiments, the stator housing is provided with an oil inlet, an oil outlet, and a copper busbar outlet communicating with the stator mounting cavity; the three-phase copper busbars of the stator winding extend outward through the copper busbar outlet.

[0028] In some embodiments, the stator core comprises a plurality of soft magnetic blocks arranged in a circumferential array.

[0029] In some embodiments, the stator winding includes a plurality of circumferentially spaced and uniformly distributed coil windings and connecting wires for connecting the coil windings; the plurality of coil windings are wound one-to-one on the plurality of soft magnetic blocks; the coil windings and the connecting wires are both flat wires.

[0030] In some embodiments, the stator housing is provided with a plurality of circumferentially spaced blocking members, the blocking members being located between the coil winding and the stator housing, so that the blocking members, the coil winding and the stator housing surround and form a cooling oil channel; the connecting line passes through the blocking members.

[0031] In some embodiments, the stator housing includes two housing components sealed by a first seal; and two stator bushings are provided, sealed by a second seal.

[0032] In some embodiments, the stator housing is provided with a sealing insert, which covers the three-phase copper busbar, is embedded in the copper busbar outlet, and is located outside the first sealing element.

[0033] In some embodiments, the stator housing is made of a non-magnetic material; the tensile strength of the stator housing is above 1500MPa, and the stiffness is above 20000N / mm.

[0034] In some embodiments, the stator housing is made of carbon fiber or phenolic resin.

[0035] In some embodiments, the axial flux motor adopts a fractional slot structure; the cores of the stator assembly, the first rotor assembly, and the second rotor assembly are all soft magnetic and are arranged in a circumferential array; the windings of the stator assembly are flat wire concentrated winding structures; and the effective air gap of the axial flux motor is less than 2 mm.

[0036] In a second aspect of this application, an electric drive system is provided, comprising:

[0037] Housing assembly;

[0038] The controller is connected to the housing assembly;

[0039] At least one of the aforementioned axial flux motors is mounted in the housing assembly and electrically connected to the controller assembly.

[0040] In some embodiments, there are two axial flux motors, which are arranged side by side along the axial direction with the second rotor assembly close to each other.

[0041] In some embodiments, the electric drive system further includes:

[0042] Two reducers are installed in the housing assembly and are respectively connected to the first rotor assemblies of the two axial flux motors;

[0043] Two resolvers are respectively connected to the second rotor assemblies of the two axial flux motors.

[0044] In a second aspect of this application, a vehicle is provided, including at least one of the aforementioned axial flux motors; and / or, including at least one of the aforementioned electric drive systems.

[0045] The axial flux motor provided according to one or more embodiments of this application adopts a single-stator dual-rotor configuration with the stator centrally located and the rotors arranged on both sides. It includes a stator assembly and a first rotor assembly and a second rotor assembly distributed on both sides of the stator assembly. The first rotor assembly and the second rotor assembly are respectively connected to the stator assembly via first rotor bearings and second rotor bearings. Because the single-stator dual-rotor axial flux motor contains only one stator assembly, it has less energy loss and less heat generation, resulting in higher power density and higher energy conversion efficiency.

[0046] The axial flux motor provided in this application has a rotor shaft that passes through the stator assembly. Both the first and second rotor bearings are mounted on the rotor shaft. One end of the rotor shaft is fixedly connected to the output section of the first rotor assembly, and the other end is drive-connected to the output section of the second rotor assembly. Compared to a design where both ends are drive-connected, this structure, with one end of the rotor shaft fixed and the other end drive-connected, allows for the pressing of only one bearing during the assembly of the stator and rotor assemblies. The bearing corresponding to the fixed end of the rotor shaft can be pre-assembled on the rotor shaft, thus reducing the difficulty of assembling the motor assembly. Furthermore, the fixed end of the rotor shaft can serve as an installation reference, resulting in smaller tolerances in the relative positions of the two rotor assemblies and ensuring one-to-one correspondence of the magnetic poles of the magnets in the two rotor assemblies, reducing the difficulty of motor calibration after assembly. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 shows a schematic diagram of the structure of an axial flux motor in one or more embodiments of this application.

[0049] Figure 2 shows a cross-sectional view of the axial flux motor of Figure 1.

[0050] Figure 3 shows an exploded view of the second rotor assembly of the axial flux motor of Figure 1.

[0051] Figure 4 shows a schematic diagram of the turntable structure of the second rotor assembly in Figure 1.

[0052] Figure 5 shows a schematic diagram of the assembly structure of the turntable and rotor core of the second rotor assembly in Figure 1.

[0053] Figure 6 shows a schematic diagram of the assembly structure of the turntable, rotor core, and rotor magnet of the second rotor assembly in Figure 1.

[0054] Figure 7 shows a schematic diagram of the rotor skeleton of the second rotor assembly in Figure 1.

[0055] Figure 8 shows a schematic diagram of the magnet unit of the second rotor assembly in Figure 1.

[0056] Figure 9A shows a schematic diagram of the structure of the magnet unit of the rotor assembly in some other embodiments of this application.

[0057] Figure 9B shows a schematic diagram of the structure of the magnet unit of the rotor assembly in some other embodiments of this application.

[0058] Figure 10A shows a schematic diagram of the structure of the first rotor assembly in Figure 1.

[0059] Figure 10B shows a schematic diagram of the structure of the second rotor assembly in Figure 1.

[0060] Figure 11 shows a schematic diagram 1 of the stator assembly in one or more embodiments of this application. The first rotor bearing and the second rotor bearing are hidden to facilitate the display of the internal structure of the stator bushing.

[0061] Figure 12 shows an exploded view of the stator assembly of Figure 11.

[0062] Figure 13 shows a full sectional view 1 of the stator assembly of Figure 11.

[0063] Figure 14 shows a schematic diagram of the housing components of the stator assembly in Figure 11.

[0064] Figure 15 shows a schematic diagram of the assembly structure of the stator winding and stator core of the stator assembly in Figure 11.

[0065] Figure 16 shows a schematic diagram of the flow path of the cooling oil in the stator assembly of Figure 11.

[0066] Figure 17 shows a schematic diagram of the cooling oil passages of the stator assembly in Figure 16.

[0067] Figure 18 shows a schematic diagram of the connection structure of the winding coil, connecting wire and blocking element in the stator winding of Figure 15.

[0068] Figure 19 shows a schematic diagram of the structure of the sealing insert of the stator assembly in Figure 11.

[0069] Figure 20 shows a schematic diagram of the stator bushing of the stator assembly in Figure 11.

[0070] Figure 21 shows a schematic diagram of the structure of an electric drive system in one or more embodiments of this application.

[0071] Figure 22 shows a full cross-sectional view of the electric drive system of Figure 21.

[0072] Figure 23 shows a schematic diagram of the assembly structure of the planetary gearbox and reduction gearbox in the electric drive system of Figure 22.

[0073] Figure 24 shows a schematic diagram of the oil collection pan in the electric drive system of Figure 21.

[0074] Figure 25 shows a schematic diagram of the oil collection pan in the electric drive system of Figure 21.

[0075] Figure 26 shows a full cross-sectional view of the oil collection pan in the electric drive system of Figure 21.

[0076] Figure 27 shows a second full cross-sectional view of the oil collection pan in the electric drive system of Figure 21.

[0077] Figure 28 shows a comparison of eddy current losses for different rotor assemblies.

[0078] Figure 29 shows a comparison of eddy current losses of the magnet units in different rotor assemblies.

[0079] Explanation of reference numerals in the attached drawings: 1000 - Electric drive system; 100 - Axial flux motor; 110 - Stator assembly; 111 - Stator housing; 111a - Stator mounting cavity; 111b - Oil inlet; 111c - Oil outlet; 111d - Copper busbar outlet; 111e - Cooling oil passage; 111f - Annular hole; 111g - First sealing groove; 111h - Clamping groove; 111i - Core fixing groove; 1111 - Housing component; 1112 - Support block; 1113 - Inner ring; 1114 - Outer ring; 112 - Stator winding; 1121 - Coil winding; 1122 - Connecting wire; 11221 - Stator winding; - Main body section, 11222- Joint section, 1123- Blocking component, 1124- Three-phase copper busbar; 113- Stator core, 1131- Soft magnetic block; 114- Stator bushing, 1141- Stop step, 1142- Shaft hole, 1143- Ring plate, 1144- Bushing bolt; 115a- First rotor bearing; 115b- Second rotor bearing; 116- Sealing insert, 1161- Insert body, 1162- Sealing sleeve; 117- First seal, 118- Second seal; 119- Pressure plate. 120a - First rotor assembly; 120b - Second rotor assembly; 121 - Rotor shaft; 1211 - First shaft section; 1212 - Splined shaft; 1213 - Third shaft section; 1214 - Spline groove; 1215 - Shoulder; 122a - First turntable; 122b - Second turntable; 1221 - Internal spline; 1222 - First mounting part; 1223 - Second mounting part; 1224 - First limiting rib; 1225 - First limiting groove; 1226 - Limiting protrusion; 1227 - Lug; 12 271-Threaded through hole, 1228-Axial cavity wall, 1229-Circumferential cavity wall; 123-Rotor magnet, 1231-Magnetic unit, 12311-Magnetic sheet, 12312-Recess, 12313-Receiving groove, 12314-Groove; 124-Rotor core, 1241-Soft magnetic sheet, 12411-Second limiting rib, 1242-Second limiting groove; 125-Rotor frame, 1251-Fixing ring, 1252-Stop arm, 1253-Connecting part; 126-Rotor bolt; 130-Pressure ring. 200-Housing assembly; 210-Motor housing; 210a-Motor mounting cavity; 211-Mounting plate; 220-Gearbox; 220a-Gearbox mounting cavity; 221-Gearbox housing; 222-End cover; 230-Controller housing; 230a-Controller mounting cavity; 231-Main body; 232-Cover plate.300-Controller; 400-Reducer; 410-Planetary gear set; 411-Sun gear; 4111-Input shaft; 4112-Support stop; 412-Planet carrier; 4121-Output shaft; 4122-Lead flange; 413-Planetary gear; 414-Planetary gear shaft; 414a-Oil guide chamber; 414b-Oil guide hole; 415-Ring gear; 420-First bearing; 430-Second bearing; 440-Third bearing; 450-Oil collection tray; 450a-Oil collection chamber; 451-Oil outlet; 452-Oil baffle; 453-Clearing area; 454-Mounting hole; 460-Fourth bearing; 500-Oil pump; 600-Oil cooler; 700-Resolver; 801-First oil seal; 802-Second oil seal. Detailed Implementation

[0080] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0081] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this application. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0082] The working principle of an axial flux motor is primarily based on the principle of electromagnetic induction. When alternating three-phase current is passed through the stator's three-phase lines, an alternating rotating induced magnetic field is generated. This induced magnetic field interacts with the fixed magnetic field generated by the rotor's permanent magnets, producing a magnetic pull that drives the rotor to rotate. Analyzing the basic principle of an axial flux motor, the generation of an alternating rotating induced magnetic field by passing alternating three-phase current through the stator's three-phase lines essentially converts the stator windings into a magnetic field through current. Some energy loss occurs during the conversion of electromagnetic energy into mechanical energy. However, the rotor directly uses magnets, which are inherently magnetic, resulting in a higher efficiency in energy conversion (magnetic energy to mechanical energy).

[0083] Under the same external envelope conditions, compared to a "dual-stator single-rotor" axial flux motor with the rotor centrally located and stators arranged on both sides, current flows through both stators, resulting in doubled energy loss and greater stator heat generation. A "single-stator dual-rotor" axial flux motor, because it contains only one stator assembly, has less energy loss and less heat generation. Therefore, it has higher power density and higher energy conversion efficiency.

[0084] However, compared to other configurations of axial flux motors, dual-rotor axial flux motors are more difficult to assemble for the following reasons: 1. During assembly, the permanent magnets generate a large axial magnetic pull, resulting in a strong magnetic attraction between the stator and rotor when they are close together, which may lead to the risk of lateral slippage of the suction cups; 2. Axial flux motors require various fixed platform devices to ensure installation accuracy, but in a single-stator dual-rotor axial flux motor, the stator is supported and assembled with bearings in the middle, and the stator cannot be supported and stabilized by fixed centers; 3. Bearings are usually installed using interference fits, which greatly increases the complexity and difficulty of bearing installation.

[0085] The manufacturing and assembly of axial flux motors are more complex, and their mass commercialization is difficult, thus limiting their widespread application. Therefore, this application provides an axial flux motor, an electric drive system, and a vehicle, which can at least partially solve the aforementioned technical problems. The specific technical solutions of this application will be described in detail below with reference to the accompanying drawings, which are not necessarily drawn to scale. Similar or identical reference numerals may be used to designate the same or similar parts in different figures. The use of similar or identical reference numerals in different figures does not mean that all figures including similar or identical reference numerals constitute a single or the same embodiment. The accompanying drawings illustrate the various embodiments discussed in this application in a generalized, illustrative, and not limiting manner.

[0086] According to a first aspect of this application, an axial flux motor 100 is provided. Referring to Figures 1 and 2, a schematic diagram and a full sectional view of the axial flux motor 100 are shown, respectively. The axial flux motor 100 includes a stator assembly 110 and a first rotor assembly 120a and a second rotor assembly 120b located on both sides of the stator assembly 110. The first rotor assembly 120a is connected to the stator assembly 110 via a first rotor bearing 115a, and the second rotor assembly 120b is connected to the stator assembly 110 via a second rotor bearing 115b. The stator assembly 110 has a shaft hole 1142 through which a rotor shaft 121 passes. The rotor shaft 121 of the axial flux motor 100 passes through the stator assembly 110. The rotor shaft 121 is fixedly connected to the output portion of the first rotor assembly 120a, and is drively connected to the output portion of the second rotor assembly 120b. Both the first rotor bearing 115a and the second rotor bearing 115b are mounted on the rotor shaft 121.

[0087] For ease of understanding, the side containing the first rotor assembly 120a is designated as the first side, also known as the first end; the side containing the second rotor assembly 120b is designated as the second side, also known as the second end. The extension direction of the rotor shaft 121 of the axial flux motor 100 is designated as the axial direction; the circumferential direction of the disk structure of the axial flux motor 100 is designated as the circumferential direction; and the direction of the line connecting the center to the circumference of the stator assembly 110 and rotor assembly of the axial flux motor 100 is designated as the radial direction. The terms first side, first end, second side, second end, axial direction, circumferential direction, and radial direction used below can all refer to the definitions above.

[0088] In some embodiments, the rotor shaft 121 and the output section of the first rotor assembly 120a are integrally formed; the rotor shaft 121 is keyed to the output section of the second rotor assembly 120b. It is understood that the rotor shaft 121 itself can also directly serve as the output section of the first rotor assembly 120a. The rotor shaft 121 includes at least a first shaft segment 1211 and a splined shaft 1212 connected together. The first rotor bearing 115a and the second rotor bearing 115b are both mounted on the first shaft segment 1211, and the splined shaft 1212 is keyed to the output section of the second rotor assembly 120b.

[0089] Referring to Figure 2, in some embodiments, the rotor shaft 121 includes a first shaft segment 1211, a splined shaft 1212, and a third shaft segment 1213 connected in sequence. The first rotor bearing 115a and the second rotor bearing 115b are both interference-fitted with the first shaft segment 1211. The splined shaft 1212 is keyed to the output section of the second rotor assembly 120b. The third shaft segment 1213 is used to install a pressure ring 130 to limit the axial displacement of the splined shaft 1212 and the second rotor assembly 120b.

[0090] Please refer to Figures 10A and 10B, which show schematic diagrams of the first rotor assembly 120a and the second rotor assembly 120b, respectively. Figure 3 shows an exploded view of the second rotor assembly 120b. For ease of understanding, the following description will be based on the exploded view of the second rotor assembly 120b in conjunction with Figure 3. Unless otherwise stated, the exploded view description of the second rotor assembly 120b is also applicable to the first rotor assembly 120a.

[0091] Referring to Figures 3, 10A, and 10B, in some embodiments, both the first rotor assembly 120a and the second rotor assembly 120b include a turntable, a rotor core 124, rotor magnets 123, and a rotor frame 125 arranged sequentially. The turntable is connected to the rotor frame 125 to axially limit the rotor core 124 and rotor magnets 123. The rotor core 124 and rotor magnets 123 are arranged in a circumferential array. For ease of understanding, the turntable of the first rotor assembly 120a is referred to as the first turntable 122a, and the turntable of the second rotor assembly 120b is referred to as the second turntable 122b. The rotor shaft 121 and the first turntable 122a are an integral structure, and the spline shaft 1212 of the rotor shaft 121 is keyed to the internal spline 1221 of the second turntable 122b. Unless otherwise specified, the description of "disc" in the following text applies to both the first disc 122a and the second disc 122b.

[0092] The rotor core 124 and rotor magnets 123 can be integral or separate structures, and this application does not impose any limitations. Referring to Figure 6, in some embodiments, the rotor magnets 123 include a plurality of magnet units 1231 arranged in a circumferential array, with a certain circumferential gap between adjacent magnet units 1231, and these gaps are equal. The magnet units 1231 can be rectangular, circular, polygonal, fan-shaped, etc., and this application does not impose any limitations. Referring to Figures 6 and 8, in some embodiments, the magnet units 1231 are fan-shaped, such that the width of the gap between adjacent magnet units 1231 remains constant radially. The gap between adjacent magnet units 1231 can be used for airflow, allowing the rotor assembly to be naturally cooled.

[0093] In some embodiments, the magnet unit 1231 is provided with a groove 12314, which penetrates the magnet unit 1231 along its thickness direction (i.e., axial direction). The shape of the groove 12314 can be a straight groove 12314 (as shown in FIG8), an arc-shaped groove 12314 (as shown in FIG9A), an S-shaped groove 12314, or a vortex groove 12314 (as shown in FIG9B), and this application does not impose any limitations.

[0094] In some embodiments, the magnet unit 1231 adopts a stepped segmented design. Referring to Figures 8 and 9A, the magnet unit 1231 includes several magnetic steel sheets 12311 stacked radially, with adjacent magnetic steel sheets 12311 glued together. The magnetic steel sheets 12311 are flat or curved plates. When the magnetic steel sheet 12311 is flat, the grooves 12314 of the magnet unit 1231 can be considered as straight grooves 12314, and the magnet block can be cut into several magnetic steel sheets 12311 by wire cutting, which has high precision. Then, the magnetic steel sheets 12311 are glued together with very thin glue, generally 20-30 μm thick. When the magnet plate 12311 is an arc-shaped plate, the groove 12314 of the magnet unit 1231 can be regarded as an arc-shaped groove 12314. Furthermore, the radius of curvature of the arc-shaped plate can be set to be the same as the radius of the rotor circumference at the location of the arc-shaped plate.

[0095] Referring to Figures 6 and 8, in some embodiments, the side of the magnet unit 1231 is provided with a recess 12312. The recesses 12312 of two adjacent magnet units 1231 form a receiving groove 12313. The opening of the receiving groove 12313 faces the side where the rotor frame 125 is located. The rotor frame 125 is embedded in the receiving groove 12313 and abuts against the bottom wall of the recess 12312. By providing this recess 12312, the rotor frame 125 can be installed, while avoiding the rotor frame 125 covering the main body of the magnet unit 1231 and affecting the magnetic circuit. The rotor frame 125 can abut against the circumferential groove wall of the receiving groove 12313, so that the rotor frame 125 can not only limit the axial movement of the rotor magnet 123, but also limit the tangential movement of the rotor magnet 123, overcoming the centrifugal force of the high-speed rotation of the rotor magnet 123 and suppressing the tangential movement of the rotor magnet 123.

[0096] In some embodiments, the thickness of the rotor frame 125 is no greater than the depth of the receiving groove, and the rotor frame 125 will not protrude after being embedded in the receiving groove. That is, the rotor frame 125 will not increase the axial dimension of the rotor assembly. In some embodiments, the rotor frame 125 is a carbon fiber frame, which has high structural strength and light weight, and can further reinforce the magnets. Referring to Figure 7, a schematic diagram of the rotor frame 125 is shown. The rotor frame 125 includes a fixed ring 1251 located at the center and a plurality of retaining arms 1252 connected to the fixed ring 1251 circumferentially. The number of retaining arms 1252 is the same as the number of magnet units 1231. The outer end of the retaining arm 1252 is provided with a connecting part 1253 for mounting rotor bolts 126. The rotor frame 125 is connected to the turntable by a plurality of rotor bolts 126.

[0097] The turntable not only serves as the output section of the rotor assembly but also mounts the rotor core 124, rotor magnets 123, and rotor frame 125, and provides positioning for these components. Referring to Figure 4, in one embodiment, the turntable is a disc-shaped slot structure with an inner cavity. The rotor core 124, rotor magnets 123, and rotor frame 125 are all located within the inner cavity of the turntable. The outer circumference of the turntable is provided with several lugs 1227 having threaded through holes 12271. The rotor frame 125 is connected to the lugs 1227 of the turntable by several rotor bolts 126. The length of the stud section of the rotor bolt 126 extending into the threaded through hole 12271 is less than the axial length of the threaded through hole 12271, allowing the remaining portion of the threaded through hole 12271 to be screwed onto the bolts on the rotor tooling during motor assembly, thus achieving multiple uses for the threaded through hole 12271. As another implementation, the turntable can also be a hollowed-out skeleton structure (refer to the structure of rotor skeleton 125), with several mounting posts with threaded holes for connecting to rotor skeleton 125. Further implementations of the turntable are not exhaustive here.

[0098] In some embodiments, the turntable has an inner cavity, within which a limiting structure is provided to tangentially limit the movement of the rotor core 124. The specific form of the limiting structure is designed according to the structure of the rotor core 124. For example, in some embodiments, the rotor core 124 is annular, and the limiting structure can be a concave-convex structure that mates with the rotor core 124. In other embodiments, referring to Figures 3 and 5, the rotor core 124 includes a plurality of soft magnetic sheets 1241 arranged in a circumferential array. The axial cavity wall 1228 of the turntable is provided with a plurality of first limiting ribs 1224 spaced apart circumferentially. The inner cavity of the turntable is divided into a plurality of first limiting grooves 1225 by the first limiting ribs 1224. The plurality of soft magnetic sheets 1241 are correspondingly disposed in the plurality of first limiting grooves 1225, and the rotor core 124 is tangentially limited by the first limiting ribs 1224, suppressing tangential movement of the rotor core 124. It is understood that the material of the rotor core 124 is not limited to soft magnetic materials. In some embodiments, the soft magnetic sheet 1241 is glued to the turntable to prevent the soft magnetic sheet 1241 from being attracted by the rotor magnet 123 during rotor assembly, and the glued fixation also limits the position of the soft magnetic sheet 1241. In some embodiments, the thickness of the rotor core 124 is 2mm to 6mm.

[0099] Referring to Figures 3 and 6, in some embodiments, the rotor magnet 123 includes a plurality of magnet units 1231 arranged in a circumferential array. A second limiting rib 12411 is provided on the soft magnetic sheet 1241. The second limiting rib 12411 is staggered from the first limiting rib 1224 and extends radially. The second limiting rib 12411 can be located in the middle or at the edge of the soft magnetic sheet 1241, which is not limited in this application. Two adjacent soft magnetic sheets 1241 form a second limiting groove 1242 through the second limiting rib 12411. The plurality of magnet units 1231 are correspondingly arranged in the plurality of second limiting grooves 1242. Since the rotor core 124 and the rotor frame 125 are distributed on opposite sides of the rotor magnet 123, the two sides of the rotor magnet 123 are tangentially and axially limited by the second limiting rib 12411 and the rotor frame 125, respectively. Furthermore, in some embodiments, the inner circumferential surface of the rotor magnet 123 abuts against the fixing ring 1251 of the rotor frame 125, and the outer circumferential surface abuts against the circumferential cavity wall 1229 of the turntable. The radial positioning of the rotor magnet 123 is achieved jointly by the turntable and the rotor frame 125.

[0100] The above structure enables the various components of the rotor assembly to form a complete assembly and rotate together. Furthermore, the first limiting rib 1224 of the turntable tangentially limits the rotor core 124, and the second limiting rib 12411 of the rotor core 124 and the rotor frame 125 tangentially limit the rotor magnet 123. This reduces the axial thickness of the tangential limiting structure, resulting in higher strength and easier manufacturing of the parts.

[0101] The turntable can also serve as a mounting base for other accessories of the axial flux motor. In some embodiments, the turntable has at least one outwardly protruding portion, which is annular and can be used for bearing positioning, mounting resolvers, mounting oil seals, mounting retaining rings, etc. As one implementation, both the first turntable 122a and the second turntable 122b have two outwardly protruding portions. The two outwardly protruding portions of the first turntable 122a are: a first mounting portion 1222 on the first end face of the first turntable 122a, used for mounting an oil seal; and a positioning protrusion 1226 on the second end face of the first turntable 122a, used for axially positioning the first side of the first rotor bearing 115a. The two outwardly protruding portions of the second turntable 122b are: a second mounting portion 1223 on the second end face of the second turntable 122b, used for mounting the rotor of the resolver; and a positioning protrusion 1226 on the first end face of the second turntable 122b, used for axially positioning the second side of the second rotor bearing 115b.

[0102] Referring to Figures 11, 12, and 13, in some embodiments, the stator assembly 110 includes a stator housing 111 with a stator mounting cavity 111a, and a stator winding 112 and a stator core 113 located in the stator mounting cavity 111a, with the stator winding 112 wound on the stator core 113. Based on the rotor assembly, the rotor magnets 123 and rotor core 124 are arranged in a circumferential array. In some embodiments, the stator windings 112 and stator core 113 are also arranged in a circumferential array. The stator windings 112 employ a high-voltage resistant concentrated flat wire winding design, with each stator winding 112 wound on a corresponding stator core 113. In some embodiments, the stator core 113 is made of a soft magnetic material, and the stator windings 112 employ concentrated flat wire windings, resulting in a slot fill factor higher than 65% for the axial flux motor 100, leading to higher operating efficiency.

[0103] Referring to Figure 15, in some embodiments, the stator core 113 includes a plurality of soft magnetic blocks 1131 arranged in a circumferential array, the plurality of soft magnetic blocks 1131 being uniformly and spaced apart along the circumferential direction. It is understood that the material of the stator core 113 is not limited to soft magnetic materials. The stator winding 112 includes a plurality of coil windings 1121 spaced apart and uniformly distributed along the circumferential direction, and connecting wires 1122 for connecting the coil windings 1122. The plurality of coil windings 1121 are wound one-to-one with the plurality of soft magnetic blocks 1131. To facilitate fixing the connecting wires 1122, in some embodiments, the stator housing 111 is provided with a plurality of blocking members 1123, the blocking members 1123 being located between the coil windings 1121 and the stator housing 111, the connecting wires 1122 passing through the blocking members 1123, and the connecting wires 1122 being fixed by the blocking members 1123. To avoid interference with the magnetic field, the blocking component 1123 is made of a non-magnetic material, such as non-metallic materials like plastic, carbon fiber, rubber, or ceramics, or a non-magnetic metal.

[0104] Referring to Figure 18, in some embodiments, both the coil winding 1121 and the connecting wire 1122 are flat wires. To facilitate the connection of the connecting wire 1122 to the blocking member 1123 and the coil winding 1121, in some embodiments, the connecting wire 1122 includes a main body segment 11221 and a connector segment 11222. The main body segment 11221 is straight or curved and passes through the blocking member 1123. The connector segment 11222 is welded to the coil winding 1121, and the connector segment 11222 is typically bent.

[0105] To limit the tangential movement of the stator core 113, referring to Figure 14, in some embodiments, the stator housing 111 is provided with a plurality of core fixing slots 111i communicating with the stator mounting cavity 111a. The end of the stator core 113 is embedded in the core fixing slot 111i and abuts against the stator housing 111, thereby limiting the axial, tangential, and radial movement of the stator core 113. It is understood that the axial dimension of the stator core 113 is larger than that of the stator winding 112, such that at least one end of the stator core 113 is exposed relative to the stator winding 112, and the exposed portion of the stator core 113 extends into the core fixing slot 111i. The area between the iron core fixing slots 111i abuts against the stator winding 112, that is, the slot wall of the iron core fixing slot 111i abuts against the coil winding 1121. The stator housing 111 and the stator iron core 113 together limit the stator winding 112 in the axial, tangential and radial directions.

[0106] In some embodiments, the core fixing groove 111i is formed in a recessed area in the stator housing 111. The core fixing groove 111i is located at least on the axial inner wall of the stator housing 111 on the side near the rotor of the axial flux motor. It can not only limit the stator core 113, but also reduce the thickness of the barrier between the rotor magnet and the stator core 113 in the axial flux motor, thereby reducing the influence of the stator housing 111 on the magnetic circuit.

[0107] The number, shape, and distribution of the core fixing slots 111i are the same as those of the soft magnetic blocks 1131. The core fixing slots 111i and the soft magnetic blocks 1131 can be fitted with either an interference fit or a clearance fit. To further fix the soft magnetic blocks 1131, adhesive can be applied to the core fixing slots 111i, and the adhesive can be used to glue and fix each soft magnetic block 1131 to the stator housing 111.

[0108] The stator assembly 110 of the motor is typically cooled by three methods: water cooling, air cooling, and oil cooling. Water cooling usually involves installing a cooling water jacket on the outside of the stator assembly 110 or installing cooling water channels in the inner wall of the motor housing, achieving cooling of the stator assembly 110 through heat exchange with the air. Air cooling also achieves cooling of the stator assembly 110 through heat exchange with the air; however, both of these cooling methods have relatively low cooling efficiency. In contrast, oil cooling is generally an immersion cooling method, where the cooling oil is in direct contact with the stator assembly 110, resulting in high cooling efficiency. In some embodiments, the axial flux motor 100 employs an internal stator immersion oil cooling method.

[0109] Referring to Figure 14, in some embodiments, the stator housing 111 is provided with an oil inlet 111b, an oil outlet 111c, and a copper busbar outlet 111d communicating with the stator mounting cavity 111a. The three-phase copper busbars 1124 of the stator winding 112 extend outward through the copper busbar outlet 111d. Blocking members 1123 are circumferentially spaced between the coil winding 1121 and the stator housing 111, so that the blocking members 1123, the coil winding 1121, and the stator housing 111 enclose and form a cooling oil channel 111e. Oil flows into the cooling oil channel 111e from the oil inlet 111b, immersing the stator core 113 and the stator winding 112 in the stator mounting cavity 111a. After heat exchange with the stator core 113 and the stator winding 112, the oil flows out from the oil outlet 111c.

[0110] The stator housing 111 is annular, with an annular hole 111f for the rotor shaft 121 to pass through and for mounting the first rotor bearing 115a and the second rotor bearing 115b. The coil windings 1121 are spaced apart from both the outer annular portion 1114 and the inner annular portion 1113 of the stator housing 111. The circumferential spacing between adjacent coil windings 1121 is communicated through the spacing between the coil windings 1121 and the inner annular portion 1113. Referring to Figure 14, in some embodiments, the inner annular portion 1113 of the stator housing 111 is provided with a plurality of support blocks 1112. The shape of the end face of the support block 1112 matches the end shape of the coil winding 1121, and the support block 1112 abuts against the corresponding end of the coil winding 1121, radially limiting the coil winding 1121.

[0111] In some embodiments, the number of support blocks 1112 is less than the number of coil windings 1121, such that the circumferential gap between adjacent coil windings 1121 is connected through the area between the coil winding 1121 and the inner ring portion 1113 where no support block 1112 is provided. As one implementation, a support block 1112 can be provided every other coil winding 1121. By providing support blocks 1112, the coil windings 1121 can be supported radially, and the oil flow along the gap between the coil windings 1121 and the inner ring portion 1113 can be prevented from forming a circulation, forcing the oil into the circumferential gap between adjacent coil windings 1121.

[0112] In some embodiments, the gap between the outer ring portion 1114 of the coil winding 1121 and the stator housing 111 is larger than the gap between the inner ring portion 1113 of the coil winding 1121 and the stator housing 111. In this case, the oil will mainly flow within the gap between the coil winding 1121 and the outer ring portion 1114, and it will be difficult for the oil to actively enter the circumferential gap between adjacent coil windings 1121 and the gap between the coil winding 1121 and the inner ring portion 1113. By placing the blocking member 1123 in the gap between the coil winding 1121 and the outer ring portion 1114, and distributing the blocking member 1123 and the circumferential gap between adjacent coil windings 1121 in a staggered manner, the oil is forced to flow into the circumferential gap between adjacent coil windings 1121 and the gap between the coil winding 1121 and the inner ring portion 1113, thereby forming the S-shaped circulating cooling circuit shown in FIG17, which has a larger heat dissipation area and better cooling effect.

[0113] To facilitate the installation of the stator core 113 and stator winding 112, the stator housing 111 adopts a split structure. In some embodiments, the stator housing 111 includes two housing components 1111, which together form a stator mounting cavity 111a. The two housing components 1111 are sealed by a first sealing element 117, which provides an outer ring seal for the stator housing 111. The oil inlet 111b, oil outlet 111c, and copper busbar outlet 111d can be respectively located on different housing components 1111, or they can be formed by the two housing components 1111 together. The two housing components 1111 can have the same structure, which is equivalent to dividing the housing component 1111 in half; the two housing components 1111 can also have different structures, for example, one is an annular groove and the other is an annular cover plate. More structural forms of the housing components 1111 are not exhaustively listed here.

[0114] The three-phase copper busbar 1124 of the stator winding 112 extends outward through the copper busbar outlet 111d. To facilitate the installation of the three-phase copper busbar 1124 and to accommodate its thermal expansion and contraction, the size of the copper busbar outlet 111d must be larger than the size of the three-phase copper busbar 1124. This results in a tiny gap between the copper busbar outlet 111d and the three-phase copper busbar 1124, creating a leakage point. Because this gap is too small to be sealed with conventional sealants, only adhesive can be used. However, the oil has a certain pressure and a high temperature, making it difficult for the sealant to maintain the durability suitable for the environment at the installation site of the three-phase copper busbar 1124.

[0115] To address the aforementioned issues, please refer to Figures 12 and 16. In some embodiments, a sealing insert 116 is provided in the stator housing 111. The sealing insert 116 covers the three-phase copper busbar 1124, is embedded in the copper busbar outlet 111d, and is located outside the first seal 117. The first seal 117 forms a first seal at the copper busbar outlet 111d, and the sealing insert 116 forms a second seal at the copper busbar outlet 111d. This unique sealing design ensures that even under high internal pressures of 2.5 bar, the leakage pressure drop of the stator cooling system remains less than the industry standard requirement of 135 Pa / min, resulting in higher reliability.

[0116] The copper bus outlet 111d can be a single, integral opening, with the U, V, and W phase copper busbars 1124 all located within it; alternatively, the copper bus outlet 111d can have three openings, with the U, V, and W phase copper busbars 1124 each located in one of the three openings. Referring to Figure 12, the copper bus outlet 111d is located on one of the housing components 1111, and includes three openings. The other housing component 1111 has a first sealing groove 111g for assembling the first sealing element 117. The sealing insert 116 is clamped and fixed by the two housing components 1111. It is understood that the sealing insert 116 is made of an elastic material, such as rubber or silicone, and can be made of the same material as the first sealing element 117.

[0117] Please refer to Figure 19, which shows a schematic diagram of the sealing insert 116 in some embodiments. The sealing insert 116 includes a connected insert body 1161 and three sealing sleeves 1162. A three-phase copper busbar 1124 is interference-fitted with each of the three sealing sleeves 1162. The insert body 1161 is connected to two housing components 1111 respectively, which can be fixed by adhesive or bolt connection. Each of the two housing components 1111 is provided with three clamping grooves 111h, and the three sealing sleeves 1162 are respectively located in the three clamping grooves 111h and clamped and fixed by the two housing components 1111.

[0118] Considering that the sealing insert 116 is made of soft rubber, the connection point is prone to cracking if it is directly connected to the bolt. Therefore, in some embodiments, a pressure plate 119 is provided on the outer side of the sealing insert 116. The pressure plate 119 is made of metal or a high-strength non-metallic plate, such as resin. The insert body 1161 is clamped between the pressure plate 119 and the stator housing 111. Bolts pass through the insert body 1161 and the pressure plate 119, and are screwed to the two housing components 1111 respectively, thereby clamping and fixing the insert body 1161.

[0119] In some embodiments, the stator housing 111 is made of a non-magnetic material, thus not obstructing the magnetic circuit. Specifically, the non-magnetic material can be a non-metallic material, such as carbon fiber, phenolic resin, or Teflon; or a non-magnetic metallic material, such as stainless steel, aluminum alloy, or titanium alloy. The stator housing 111 primarily protects the internal stator core 113 and stator windings 112, requiring a tensile strength of at least 1500 MPa and a stiffness of at least 20000 N / mm. Furthermore, to minimize the air gap between the stator and rotor, the wall thickness at the thinnest point of the stator housing 111 should not exceed 1 mm.

[0120] In some embodiments, the stator housing 111 is made of carbon fiber. The thinnest part of the carbon fiber stator housing 111 (at the core fixing groove 111i) has a wall thickness of only 0.5 mm to 0.7 mm. The high-strength carbon fiber material makes the stator housing 111 extremely rigid and strong, capable of withstanding torques of over 600 N·m and compressive forces of over 10,000 N without damage. In addition, the use of carbon fiber material makes the physical air gap between the stator and rotor (the physical air gap is the air gap between the rotor magnet 123 and the stator housing 111; the distance between the end faces of the rotor magnet 123 and the stator core 113 is called the effective air gap, which is 1.8 mm) even smaller, only 1.3 mm, resulting in a higher peak torque power of the axial flux motor 100.

[0121] Since the stator housing 111 is made of non-metallic material, to strengthen the structure of the stator housing 111, the stator assembly 110 also includes two stator bushings 114, both of which are metal bushings. The stator housing 111 is annular, and the two stator bushings 114 are embedded in the annular holes 111f of the stator housing 111. The inner cavities of the two stator bushings 114 form the shaft holes 1142 of the stator assembly 110. The inner walls of the two stator bushings 114 are provided with stop steps 1141. The two ends of the first rotor bearing 115a are axially limited by the first turntable 122a and the stop step 1141 of one of the stator bushings 114, respectively. The two ends of the second rotor bearing 115b are axially limited by the second turntable 122b and the stop step 1141 of the other stator bushing 114, respectively, as shown in Figure 2.

[0122] In some embodiments, the two stator bushings 114 are respectively interference-fitted with the two housing components 1111, so that no leakage occurs between the stator bushings 114 and the corresponding housing components 1111. The two stator bushings 114 are sealed by a second seal 118. A sealing groove can be provided on either of the two stator bushings 114, or sealing grooves can be provided on the opposite end faces of the two stator bushings 114. The second seal 118 is embedded in the sealing groove and is clamped and deformed by the two stator bushings 114.

[0123] The clamping force between the two stator bushings 114 can be provided by the bolts connecting the two housing components 1111. Considering that the bolts connecting the two housing components 1111 are distributed on the outer periphery of the stator housing 111, and that both stator bushings 114 are located in the annular holes 111f of the stator housing 111, the constraint force they experience is limited. Therefore, referring to Figure 20, in some embodiments, the two stator bushings 114 are fixedly connected by bushing bolts 1144. Annular plates 1143 can be provided in both stator bushings 114 for connecting the bushing bolts 1144. After the two stator bushings 114 are locked by the bushing bolts 1144, they jointly clamp the second sealing element 118, achieving an inner ring seal of the stator housing 111.

[0124] Understandably, in some embodiments, the stator housing 111 is made of a non-magnetic metallic material with a certain strength. The stator housing 111 is then generally annular, with its inner annular hole forming a shaft hole. A stop step is provided on the hole wall of the inner annular hole of the metallic stator housing 111 to axially limit the bearing. The inner annularities of the two housing components 1111 of the metallic stator housing 111 are sealed by a second sealing element 118, achieving an inner annular seal for the stator housing 111.

[0125] In some embodiments, the axial flux motor 100 employs a fractional-slot structure, resulting in lower harmonics and torque fluctuations within 50%. As one implementation, the stator assembly 110 of the axial flux motor 100 features a 12-slot design, comprising 12 soft magnetic coils and 12 turns of flat wire coils arranged in a circular array. The connecting copper wire between the three-phase copper busbar 1124 and the coil windings 1121 is an arc, forming a concentrated stator winding scheme after close contact. The rotor assembly employs a 10-pole design, with the rotor magnets 123 using a T-shaped stepped segmented structure arranged in a circular array. The rotor magnets 123 and the turntable are connected via a soft magnetic material (i.e., the rotor core 124), which also has a T-shaped segmented structure and is bonded to the turntable using high-temperature resistant adhesive, arranged in a circular array.

[0126] The axial flux motor 100 provided according to one or more of the above embodiments has the following beneficial effects:

[0127] (1) The axial flux motor 100 provided in this application has a simple and compact structure, with unique sealing and cooling systems, as well as electromagnetic scheme structural design and material selection. Within the same volume (e.g., overall outer diameter of the axial flux motor is 310mm, thickness is 130mm; rotor assembly outer diameter is 280mm, thickness is 44mm; stator assembly outer diameter is 310mm, thickness is 45mm), compared to other types of axial flux motors, it has higher performance and efficiency. The motor has a peak torque of 650N·m, a peak power of 250KW, a maximum speed of 12000rpm, a maximum efficiency of 97.5%, and an effective air gap of less than 2mm (physical air gap is 1.3mm, effective air gap is 1.8mm). Compared to traditional radial flux motors, within the same volume, it is 30% lighter and has at least 30% higher performance.

[0128] (2) The axial flux motor 100 provided in this application uses oil immersion cooling for the stator assembly. The stator winding 112 and stator core 113 are immersed in circulating oil to dissipate heat. When 10L / min of cooling oil is circulated inside the stator housing, the average temperature inside the stator can be maintained at about 85°C and the maximum temperature is less than 150°C.

[0129] (3) The axial flux motor 100 provided in this application uses a carbon fiber skeleton to fix the rotor magnet 123, and restricts the tangential movement of the rotor magnet 123 under the action of high-speed rotation centrifugal force, as well as the axial movement under the action of magnetic attraction force.

[0130] (4) The axial flux motor 100 provided in this application has a large eddy current loss when the back plate (axial cavity wall 1228) of the rotor assembly is a single metal plate, not composed of silicon steel sheets. By installing a rotor core 124 of soft magnetic material on the rotor, and using the soft magnetic sheet 1241 as a partition between the rotor magnet 123 and the rotor, the eddy current loss of the magnet is further reduced. Under the conditions of peak speed and peak power, the rotor core 124 of soft magnetic material (SMC) installed on the rotor 122 effectively reduces eddy current loss by 85% compared to the scheme without soft magnetic material (i.e., partition = 0), as shown in Figure 28.

[0131] (5) The axial flux motor 100 provided in this application can effectively reduce eddy current losses by setting grooves 12314 in the rotor magnet 123. Compared with a whole magnet block of the same size, the eddy current losses are reduced by more than 95%. Please refer to Figure 29. Under the conditions of peak speed and peak power, the eddy current loss of the rotor magnet 123 is 2kW when it is radially segmented 20 (i.e., the magnet unit 1231 is divided into 20 segments of magnet plates 12311). Compared with the rotor magnet 123 without grooves 12314 and with radial segmentation of 0 (i.e., the magnet unit 1231 is a whole magnet block), the eddy current loss is reduced by more than 90%.

[0132] Please refer to Figures 21 and 22. A second aspect embodiment of this application provides an electric drive system including a housing assembly 200, a controller 300, and at least one axial flux motor 100 as described in any of the first aspect embodiments above. The controller 300 is electrically connected to the axial flux motor 100, providing three-phase current to the stator assembly of the axial flux motor 100, and communicating data with the vehicle controller 300 to control the operation of the axial flux motor 100 and provide feedback on the operating parameters of the axial flux motor 100.

[0133] The controller 300 is connected to the housing assembly 200. The controller 300 can be a separate component connected to the housing assembly 200. The controller 300 can also be installed inside the housing assembly 200. The axial flux motor 100 is installed in the housing assembly 200, which serves as the motor housing for the axial flux motor 100.

[0134] In some embodiments, a resolver 700 is mounted on the axial flux motor 100, and the resolver 700 is mounted on either the first rotor assembly 120a or the second rotor assembly 120b. Referring to FIG22, in some embodiments, the resolver 700 is mounted on the output section of the second rotor assembly 120b. As one embodiment, the rotor of the resolver 700 is mounted on the second turntable 122b, and the stator of the resolver 700 is mounted in the motor housing 200 of the housing assembly.

[0135] The electric drive system 1000 can be a single-motor system or a dual-motor system. In some embodiments, the electric drive system 1000 adopts a dual-motor system, that is, two axial flux motors 100 are provided. The two axial flux motors 100 are arranged side by side along the axial direction with the second rotor assembly close to each other. The electric drive system 1000 also includes two reducers 400, which are respectively connected to the two axial flux motors 100 for transmission, and are used to reduce the power output by the two axial flux motors 100 before outputting it outward. The two reducers 400 can be independent reducers 400, connected to the housing assembly 200. The reducers 400 can also be installed inside the housing assembly 200. The reducers 400 can be planetary gear sets 410, gear reduction mechanisms, etc., and this application is not limited thereto.

[0136] Please refer to Figures 21 and 22, which show a schematic diagram and a full sectional view of the electric drive system 1000 in some embodiments. The electric drive system 1000 is configured with two axial flux motors 100 and two single planetary gearboxes 410 reducers 400. The housing assembly 200 has a controller mounting cavity 230a, a motor mounting cavity 210a, and a reducer mounting cavity 220a. The controller 300 is located in the controller mounting cavity 230a. The two axial flux motors 100 are arranged side by side along the axial direction of the axial flux motors 100 in the motor mounting cavity 210a. The two planetary gearboxes 410 are located in the reducer mounting cavity 220a and are symmetrically distributed outside the two axial flux motors 100, so that the electric drive system 1000 has a generally symmetrical structure. The two planetary gearboxes 410 are respectively connected to the rotor assemblies of the two axial flux motors 100 for transmission, and are used to output the power output by the two axial flux motors 100 after reduction and torque amplification.

[0137] In some embodiments, the housing assembly 200 includes a motor housing 210, a controller housing 230, and two gearboxes 220. The two gearboxes 220 are respectively connected to the openings at both ends of the motor housing 210 and are close to the rotor assembly. The gearboxes 220 and the motor housing 210 together form a motor mounting cavity 210a, the inner cavity of the controller housing 230 forms a controller mounting cavity 230a, and the inner cavity of the gearboxes 220 forms a reducer mounting cavity 220a. Along the axial direction of the axial flux motor 100, the motor housing 210 and the two gearboxes 220 share the same wall, which can significantly reduce the axial dimension of the electric drive system 1000.

[0138] In some embodiments, the motor housing 210 and the main body 231 of the controller housing 230 are integral structures, that is, one chamber of the motor housing 210 serves as the motor mounting cavity 210a, and the other chamber serves as the controller mounting cavity 230a. The cover plate 232 of the controller housing 230 is connected to the motor housing 210 to seal the controller mounting cavity 230a. The integration of the motor housing 210 and the controller housing 230 can significantly reduce the size of the electric drive system 1000 in the direction perpendicular to the axial direction.

[0139] To further reduce the axial dimension of the electric drive system 1000 and improve its power density, please refer to Figure 22. In some embodiments, the rotor shaft 121 is provided with a spline groove 1214, and the sun gear 411 of the planetary gear set 410 is provided with an input shaft 4111, which is keyed to the spline groove 1214. The torque output by the rotor shaft 121 is transmitted to the planetary gear set 410 through the sun gear 411. In some embodiments, the first shaft section 1211 of the rotor shaft 121 is hollow, and its inner wall is provided with a spline groove 1214.

[0140] Since the splined engagement between the input shaft 4111 and the rotor shaft 121 is not visible, they can only be blind-assembled. To avoid interference during assembly, please refer to Figure 22. In some embodiments, a shoulder is provided on the inner wall of the rotor shaft 121, and a support stop 4112 is provided on the input shaft 4111. When the input shaft 4111 moves axially until the support stop 4112 abuts against the shoulder and is axially limited, the spline groove 1214 of the rotor shaft 121 stably meshes with the external spline of the input shaft 4111, and the end of the input shaft 4111 will not interfere with the cavity wall of the rotor shaft 121. In addition, the sliding engagement between the support stop 4112 and the inner wall of the rotor shaft 121 also serves to guide and ensure the coaxiality of the sun gear 411 and the rotor shaft 121.

[0141] Taking an electric drive system 1000 equipped with two axial flux motors 100 with an overall outer diameter of 310mm as an example, the outer envelope dimensions of the electric drive system 1000 are 380*420*290mm, of which the axial dimension is 420mm and the height is 290mm. The smaller axial dimension allows the electric drive system 1000 to be directly mounted between the two wheels along the Y direction (vehicle width direction), and the torque output from the two planetary gear sets 410 drives the two wheels respectively.

[0142] In the planetary gear set 410, the sun gear 411 and the input shaft 4111 can be an integral structure, or they can be connected by a key, bolt, or other means. This application does not impose any limitations. In some embodiments, the input shaft 4111 and the sun gear 411 are integrally formed to create a gear shaft. This gear shaft is hollow, reducing its weight. The hollow shaft also allows lubricating oil to enter, thereby lubricating the meshing points of the spline groove 1214 of the rotor shaft 121 and the external spline of the input shaft 4111, as well as the mating points of the support stop 4112 of the input shaft 4111 and the inner wall of the rotor shaft 121. To prevent lubricating oil from entering the motor mounting cavity 210a, a first oil seal 801 is provided between the gearbox 220 and the turntable of the adjacent rotor assembly.

[0143] Referring to Figure 22, in some embodiments, two axial flux motors 100 are arranged side-by-side along the axial direction with their second rotor assemblies 120b close to each other. The stators of the two resolvers 700 are respectively connected to the motor housing 210, and the rotors of the two resolvers 700 are respectively connected to the two second turntables 122b. Specifically, a mounting plate 211 may be provided inside the motor housing 210, and the stators of the two resolvers 700 are symmetrically mounted on both sides of the mounting plate 211 by bolts. Each of the second turntables 122b of the two axial flux motors 100 is provided with a second mounting part 1223, and the rotor of the resolver 700 is fitted onto the second mounting part 1223 with an interference fit. Each of the first turntables 122a of the two axial flux motors 100 is provided with a first mounting part 1222, which is an annular protrusion. A gearbox 220 is fitted onto the first mounting part 1222, and a first oil seal 801 is installed between the gearbox 220 and the first mounting part 1222.

[0144] Referring to Figure 23, in some embodiments, the gearbox 220 includes a gearbox housing 221 and an end cover 222 connected together. The gearbox housing 221 is connected to the motor housing 210, and an oil seal is installed between the gearbox housing 221 and the first mounting portion 1222. The planetary carrier 412 of the planetary gear set 410 is provided with an output shaft 4121, and a first bearing 420 is provided between the output shaft 4121 and the end cover 222. To prevent lubricating oil leakage, a second oil seal 802 is provided between the output shaft 4121 and the end cover 222.

[0145] In related technologies, the gearbox of a distributed dual-motor electric drive system often uses a passive lubrication and cooling method with gear-driven oil churning, resulting in high oil churning losses and low efficiency. However, compared to parallel shaft gear reduction mechanisms, the planetary gear set 410 has a more compact structure, and the gear ring 415 is not easily churning oil. Therefore, the oil churning lubrication method cannot adequately meet the lubrication requirements of the planetary gear set 410. To address this, the electric drive system 1000 provided in this application uses an oil collection tray 450 to actively spray oil for lubrication of the planetary gear set 410.

[0146] Referring to Figure 23, in some embodiments, the planetary carrier 412 is provided with an oil collection tray 450. The oil collection tray 450 is annular and is fitted onto the end of the planetary carrier 412 away from the output shaft 4121, rotating together with the planetary carrier 412. The oil collection tray 450 has the same number of oil outlets 451 as the planetary gear shafts 414 of the planetary gear set 410, allowing lubricating oil to be input into the oil collection tray 450. The lubricating oil can flow out through each oil outlet 451, flowing to each planetary gear 413 and the corresponding bearing.

[0147] Please refer to Figures 24 and 25, which show schematic diagrams of the oil collection tray 450 in some embodiments. The oil collection tray 450 is provided with a plurality of oil baffles 452, the number of which is the same as the number of oil outlets 451, and the root of each oil baffle 452 is close to the corresponding oil outlet 451. By setting the oil baffles 452, the oil can be collected at the root of the oil baffles 452 in the rotating oil collection tray 450, so that the oil can enter the oil outlet 451.

[0148] Referring to Figure 26, in some embodiments, the oil baffle 452 is radially inclined relative to the oil collection plate 450. Along the rotation direction of the oil collection plate 450, the root of the oil baffle 452 is located in front of the corresponding oil outlet 451, and the free end of the oil baffle 452 is located behind the corresponding oil outlet 451. When the oil collection plate 450 rotates in the direction indicated by the arrow in Figure 26, the oil will rotate relative to the oil collection plate 450 due to inertia. This can be understood as the oil collection plate 450 and the oil rotating in the same direction as the arrow in Figure 26, with the oil collection plate 450 rotating faster than the oil. Therefore, the oil will gradually converge at the root of the oil baffle 452 and flow along the oil baffle 452 towards its free end, eventually entering the oil outlet 451.

[0149] Please refer to Figure 27. In some embodiments, the oil collection tray 450 is mounted on the planetary carrier 412 by screws. To facilitate the installation of screws, a number of clearance areas 453 are provided on the side plate of the oil collection tray 450 away from the oil outlet 451. A number of mounting holes 454 are provided on the side plate of the oil collection tray 450 on the side where the oil outlet 451 is located. Each clearance area 453 corresponds to each mounting hole 454. During installation, a sleeve can be set in the clearance area 453, and the screw can be installed through the internal space of the sleeve to prevent the screw from accidentally falling into the oil collection chamber 450a.

[0150] The lubricating oil can be fed into the oil collection tray 450 through an externally installed oil pipe, or it can be transported through oil channels opened in the wall of the housing assembly 200. Furthermore, the cooling oil of the stator assembly 110 of the axial flux motor 100 can be mixed with the lubricating oil of the planetary gear set 410. That is, the oil first enters the stator assembly 110 to cool it, and then is transported to the oil collection tray 450 through the oil channels opened in the wall of the housing assembly 200. After lubricating the planetary gear set 410, the oil finally falls into the reducer mounting cavity 220a.

[0151] Therefore, the electric drive system 1000 also includes an oil pump 500, which is connected to the reducer mounting cavity 220a and pumps the oil falling into the reducer mounting cavity 220a to the stator assembly 110. In some embodiments, the electric drive system 1000 also includes an oil cooler 600, which is mounted on the housing assembly 200 and used to cool the oil. The oil cooler 600 can cool the oil by air cooling or water cooling, and this application is not limited to this. The oil inlet of the oil cooler 600 is connected to the oil pump 500, and the oil outlet of the oil cooler 600 is connected to the oil inlet 111b of the stator assembly 110.

[0152] A third aspect of this application provides a vehicle that includes at least one axial flux motor 100 according to any of the embodiments of the first aspect described above. And / or, the vehicle includes at least one electric drive system 1000 according to any of the embodiments of the second aspect described above. The vehicle may be a pure electric vehicle or a hybrid vehicle; this application does not impose any limitations.

[0153] In one implementation scheme, the vehicle includes four axial flux motors 100, each integrated with the wheels as a hub motor, and each axial flux motor 100 is equipped with a corresponding controller 300. In other words, this vehicle is a distributed drive four-wheel drive vehicle.

[0154] In another implementation, the vehicle includes two electric drive systems 1000, each equipped with two axial flux motors 100 as described in the first aspect embodiment, and the controller 300 of each electric drive system 1000 individually controls the corresponding axial flux motor 100. That is to say, the vehicle is also a four-wheel drive vehicle.

[0155] In another embodiment, the vehicle includes an electric drive system 1000, which is equipped with two axial flux motors 100 as described in the first aspect embodiment. The controller 300 of the electric drive system 1000 can individually control the corresponding axial flux motor 100. That is, the vehicle is a two-wheel drive vehicle. The electric drive system 1000 is mounted between the rear wheels of the vehicle in an axially parallel orientation to the Y-axis. A power battery pack is located in the center of the vehicle chassis to supply power to the electric drive system 1000.

[0156] The various powertrain options for this vehicle are not exhaustive here. Other undescribed aspects of this vehicle can be found in existing public knowledge, and will not be elaborated upon here.

[0157] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0158] In the description of this application, it is understood that the terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” and “counterclockwise” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0159] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0160] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0161] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0162] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0163] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0164] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An axial flux motor, comprising: Stator assembly; A first rotor assembly is connected to the stator assembly via a first rotor bearing, and the first rotor assembly is located on a first side of the axial direction of the stator assembly; The second rotor assembly is connected to the stator assembly via a second rotor bearing, and the second rotor assembly is located on the second side of the axial direction of the stator assembly; The rotor shaft passes through the stator assembly and is fixedly connected to the output part of the first rotor assembly. The rotor shaft is also drively connected to the output part of the second rotor assembly. Both the first rotor bearing and the second rotor bearing are mounted on the rotor shaft.

2. The axial flux motor according to claim 1, wherein, The rotor shaft and the output section of the first rotor assembly are an integral structure; the rotor shaft and the output section of the second rotor assembly are keyed together.

3. The axial flux motor according to claim 2, wherein, The rotor shaft includes a first shaft segment, a splined shaft, and a third shaft segment connected in sequence; both the first rotor bearing and the second rotor bearing are interference-fitted with the first shaft segment.

4. The axial flux motor according to claim 3, wherein, The axial flux motor also includes a pressure ring, which is interference-fitted with the third shaft segment.

5. The axial flux motor according to any one of claims 1-4, wherein, Both the first rotor assembly and the second rotor assembly include a turntable, a rotor core, a rotor magnet, and a rotor frame arranged sequentially; the turntable is connected to the rotor frame to axially limit the rotor core and the rotor magnet.

6. The axial flux motor according to claim 5, wherein, The rotor magnet comprises several magnet units arranged in a circumferential array; the magnet units are provided with grooves.

7. The axial flux motor according to claim 6, wherein, The magnetic steel unit includes several magnetic steel sheets stacked in a radial direction, and adjacent magnetic steel sheets are glued together; the magnetic steel sheets are flat plates or arc-shaped plates.

8. The axial flux motor according to claim 6, wherein, The side of the magnet unit is provided with a recess, and the recesses of two adjacent magnet units form a receiving groove. The rotor frame is embedded in the receiving groove and abuts against the bottom wall of the recess.

9. The axial flux motor according to claim 5, wherein, The turntable has an inner cavity, and the inner wall of the turntable is provided with a plurality of first limiting ribs distributed circumferentially. The inner cavity of the turntable is divided into a plurality of first limiting grooves by the first limiting ribs. The rotor core includes a plurality of soft magnetic sheets arranged in a circumferential array; the plurality of soft magnetic sheets are arranged one-to-one in a plurality of the first limiting grooves; the soft magnetic sheets are glued and fixed to the turntable.

10. The axial flux motor according to claim 9, wherein, The soft magnetic sheet is provided with a second limiting rib, which is staggered from the first limiting rib; two adjacent soft magnetic sheets form a second limiting groove through the second limiting rib; The rotor magnet includes several magnet units arranged in a circumferential array, and the several magnet units are arranged one-to-one in several second limiting grooves.

11. The axial flux motor according to claim 5, wherein, The first rotor assembly has a first turntable, which is integrally formed with the rotor shaft; the first turntable is provided with a protruding first mounting portion; The turntable of the second rotor assembly is a second turntable, which is splined with the rotor shaft; the second turntable is provided with an outwardly protruding second mounting part.

12. The axial flux motor according to claim 5, wherein, The turntables of the first rotor assembly and the second rotor assembly are provided with outwardly protruding limiting protrusions, which abut against the corresponding first rotor bearing or second rotor bearing.

13. The axial flux motor according to any one of claims 1-4, wherein, The stator assembly includes an annular stator housing with a stator mounting cavity, a stator bushing, and a stator winding and a stator core located in the stator mounting cavity; the stator winding is wound on the stator core; the stator bushing is embedded in the annular hole of the stator housing; the first rotor bearing and the second rotor bearing are both located in the stator bushing.

14. The axial flux motor according to claim 13, wherein, The stator housing is provided with an oil inlet, an oil outlet, and a copper busbar outlet that communicate with the stator mounting cavity; the three-phase copper busbars of the stator winding extend outward through the copper busbar outlet.

15. The axial flux motor according to claim 14, wherein, The stator core includes several soft magnetic blocks arranged in a circular array; The stator winding includes a plurality of coil windings spaced apart and evenly distributed along the circumference and connecting wires for connecting the coil windings; the plurality of coil windings are wound one-to-one on the plurality of soft magnetic blocks; the coil windings and the connecting wires are all flat wires.

16. The axial flux motor according to claim 15, wherein, The stator housing is provided with a plurality of circumferentially spaced blocking members, which are located between the coil winding and the stator housing, so that the blocking members, the coil winding and the stator housing surround and form a cooling oil channel; the connecting line passes through the blocking members.

17. The axial flux motor according to claim 14, wherein, The stator housing includes two housing components, which are sealed by a first sealing element; the stator bushing is provided in two parts, which are sealed by a second sealing element. The stator housing is provided with a sealing insert, which covers the three-phase copper busbar, is embedded in the copper busbar outlet, and is located outside the first sealing element.

18. The axial flux motor according to claim 13, wherein, The stator housing is made of a non-magnetic material; the tensile strength of the stator housing is above 1500MPa, and the stiffness is above 20000N / mm.

19. The axial flux motor according to claim 18, characterized in that, The stator housing is made of carbon fiber or phenolic resin.

20. The axial flux motor according to any one of claims 1-4, wherein, The axial flux motor adopts a fractional slot structure; the iron cores of the stator assembly, the first rotor assembly and the second rotor assembly are all soft magnetic and are arranged in a circular array; the winding of the stator assembly is a flat wire concentrated winding structure; the effective air gap of the axial flux motor is less than 2mm.

21. An electric drive system, comprising: Housing assembly; The controller is connected to the housing assembly; At least one axial flux motor according to any one of claims 1-20 is mounted in the housing assembly and electrically connected to the controller assembly.

22. The electric drive system according to claim 21, wherein, The axial flux motor is provided in two, and the two axial flux motors are arranged side by side along the axial direction with the second rotor assembly close to each other; The electric drive system also includes: Two reducers are installed in the housing assembly and are respectively connected to the first rotor assemblies of the two axial flux motors; Two resolvers are respectively connected to the second rotor assemblies of the two axial flux motors.

23. A vehicle comprising at least one axial flux motor as claimed in any one of claims 1-20; And / or, including at least one electric drive system as described in claim 21 or 22.

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