A rotor assembly and an axial flux electric machine

Abstract

The utility model belongs to motor technical field discloses a rotor assembly and axial flux motor. The rotor assembly includes back iron, first skeleton and a plurality of magnetic single units, and one side of back iron has inner chamber, a plurality of magnetic single units are evenly arranged in inner chamber along the circumference direction of back iron, and each magnetic single unit includes a plurality of sectional monomers arranged along the radial direction of back iron, the first skeleton is arranged in the inner chamber, and is embedded between the adjacent two magnetic single units and the adjacent two sectional monomers, and the side of the first skeleton close to back iron forms cooling channel with back iron, the cooling channel passes through the interval between the adjacent two sectional monomers, and the cooling channel is used for the medium for passing in cooling. The rotor assembly and axial flux motor provided by the utility model can reduce eddy current loss and improve the heat dissipation efficiency of sectional monomers, and ensure the stable operation of axial flux motor.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a rotor assembly and an axial flux motor. Background Technology

[0002] An axial flux motor is a type of motor in which the magnetic field is distributed along the motor axis. Unlike traditional radial flux motors, axial flux motors have a disc-shaped structure. Due to their compact structure, small size, light weight, and high torque density, they are widely used in the market.

[0003] In the prior art, the magnet unit of the rotor assembly has a fan-shaped structure and is usually segmented to reduce eddy current losses. That is, the magnet unit includes multiple segmented units arranged in sequence along the radial direction. However, after segmentation, the segmented units are closely attached to each other, and structurally they are still a whole. This increases the thermal resistance between the segmented units, which is not conducive to heat dissipation. Excessive temperature rise can cause irreversible demagnetization of the magnets, affecting the stable operation of the motor.

[0004] Therefore, there is an urgent need to provide a rotor assembly and an axial flux motor to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a rotor assembly and an axial flux motor that can reduce eddy current losses while improving the heat dissipation efficiency of individual segments, thus ensuring the stable operation of the axial flux motor.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A rotor assembly includes a back iron, a first frame, and a plurality of magnet units. The back iron has an inner cavity on one side. The plurality of magnet units are evenly spaced in the inner cavity along the circumference of the back iron. Each magnet unit includes a plurality of segmented units arranged radially spaced along the back iron. The first frame is disposed in the inner cavity and is embedded between two adjacent magnet units and between two adjacent segmented units. A cooling channel is formed between the side of the first frame near the back iron and the back iron. The cooling channel passes through the gap between two adjacent segmented units and is used to introduce a cooling medium.

[0008] As an optional solution, the bottom of the inner cavity is provided with multiple limiting grooves, which are evenly spaced along the circumference of the back iron. The number of limiting grooves is the same as the number of magnet units, and each magnet unit is housed in the corresponding limiting groove.

[0009] As an optional solution, the back iron includes a disc body, a rotating shaft, and a retaining ring. The disc body is arranged around the outer periphery of the rotating shaft, and the retaining ring is arranged around the outer periphery of the disc body and together with the disc body defines the inner cavity. The rotating shaft, the disc body, and the retaining ring are integrally formed.

[0010] As an alternative, the surface of the first frame facing away from the back iron is flush with the end face of the magnet and the retaining ring.

[0011] As an optional solution, the cooling channel includes an oil inlet straight flow channel, an oil outlet straight flow channel, and multiple annular flow channels. The multiple annular flow channels are arranged coaxially along the radial direction of the back iron and are configured to correspond one-to-one with the interval between two adjacent segment units. Each annular flow channel passes through the interval between two corresponding adjacent segment units. The oil inlet straight flow channel and the oil outlet straight flow channel are arranged circumferentially along the back iron and both extend radially along the back iron. The oil inlet straight flow channel and the oil outlet straight flow channel are both connected to the multiple annular flow channels.

[0012] As an optional solution, the rotating shaft is provided with an external oil inlet hole and an external oil outlet hole extending along its axial direction, and the disc body is provided with an internal oil inlet hole and an internal oil outlet hole horizontally. One end of the internal oil inlet hole is connected to the external oil inlet hole, and the other end of the internal oil inlet hole is connected to the oil inlet straight flow channel. One end of the internal oil outlet hole is connected to the external oil outlet hole, and the other end of the internal oil outlet hole is connected to the oil outlet straight flow channel.

[0013] As an optional embodiment, the first skeleton includes a circular portion, multiple baffles, and multiple first annular ribs. The multiple baffles are uniformly connected to the outer periphery of the circular portion along its circumference. The number of baffles is the same as the number of magnet units. Each baffle is embedded between two adjacent magnet units. The multiple first annular ribs are arranged coaxially along the radial direction of the circular portion and are connected to each baffle in the circumferential direction. The number of first annular ribs is the same as the number of annular channels. Each first annular rib is embedded in the interval between two adjacent segment units.

[0014] As an optional solution, the bottom of the inner cavity is provided with multiple annular grooves, which are arranged coaxially and spaced apart along the radial direction of the disc. Each baffle arm includes multiple baffle units arranged at intervals along its radial direction. Along the radial direction of the baffle arm, each first annular rib is connected between two adjacent baffle units, and an arc-shaped groove is formed between two adjacent baffle units. The arc-shaped groove and the annular groove are arranged in a one-to-one correspondence. The first annular rib, the arc-shaped groove, and the annular groove together define the annular flow channel.

[0015] As an optional solution, the rotor assembly further includes a second frame, which includes a plurality of second annular ribs, each corresponding to one of the annular grooves, and the second annular ribs are embedded in the corresponding annular grooves.

[0016] An axial flux motor includes at least one stator assembly and at least one rotor assembly as described above, the rotor assembly and the stator assembly being alternately distributed along the axial direction.

[0017] The beneficial effects of this utility model are:

[0018] This invention provides a rotor assembly and an axial flux motor. By dividing each magnet unit into multiple segments arranged radially, the circumferential eddy current path can be effectively blocked, reducing eddy current losses. Furthermore, the spacing between the multiple segments increases the heat dissipation area of ​​each segment, which is beneficial for heat dissipation. In addition, by forming a cooling channel between the first frame and the back iron, and by passing through the gap between two adjacent segments, and by introducing a cooling medium into the cooling channel, each segment of each magnet unit can be directly cooled with oil, thereby improving the heat dissipation efficiency of the rotor assembly and ensuring the stable operation of the axial flux motor. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the rotor assembly provided in an embodiment of the present invention;

[0020] Figure 2 This is an exploded view of the rotor assembly provided in this embodiment of the present invention;

[0021] Figure 3 This is a radial sectional view of the rotor assembly provided in this embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the back iron structure provided in an embodiment of the present utility model;

[0023] Figure 5 This is a schematic diagram of the structure of the first skeleton provided in this embodiment of the utility model. Figure 1 ;

[0024] Figure 6 This is a schematic diagram of the structure of the first skeleton provided in this embodiment of the utility model. Figure 2 ;

[0025] Figure 7 This is a schematic diagram of the cooperation between the back iron and the second frame provided in an embodiment of the present invention.

[0026] In the picture:

[0027] 10. Back iron; 101. Limiting groove; 11. Disc body; 111. Annular groove; 112. Inner oil inlet hole; 113. Inner oil outlet hole; 12. Rotating shaft; 121. Outer oil inlet hole; 122. Outer oil outlet hole; 13. Retaining ring; 14. Inner cavity;

[0028] 20. Magnet unit; 21. Segmented unit;

[0029] 30. First frame; 31. Circular part; 32. Stop arm; 321. Baffle unit; 322. Arc groove; 33. First annular rib;

[0030] 40. Second skeleton; 41. Second annular reinforcement;

[0031] 50. Cooling channel; 51. Oil inlet straight flow channel; 52. Oil outlet straight flow channel; 53. Annular flow channel. Detailed Implementation

[0032] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar parts or parts having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0033] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] In the description of this utility model, 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 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 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.

[0035] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0036] like Figures 1 to 3 As shown, this embodiment provides a rotor assembly, including a back iron 10, a first frame 30, and multiple magnet units 20. The back iron 10 serves as the output part of the rotor assembly, used to output the power of the rotor assembly. One side of the back iron 10 has an inner cavity 14. The multiple magnet units 20 are evenly spaced in the inner cavity 14 along the circumference of the back iron 10. Each magnet unit 20 includes multiple segmented units 21 arranged radially spaced along the back iron 10. The first frame 30 is disposed in the inner cavity 14 and embedded between two adjacent magnet units 20 and two adjacent segmented units 21. The side of the first frame 30 closest to the back iron 10 forms a cooling channel 50 with the back iron 10. The cooling channel 50 passes through the gap between two adjacent segmented units 21 and is used to circulate a cooling medium. In this embodiment, the magnet unit 20 is generally fan-shaped, and the circumferential dimension of the magnet unit 20 gradually increases radially from the inside to the outside.

[0037] In this embodiment, by dividing each magnet unit 20 into multiple segmented units 21 arranged radially in sequence, the circumferential eddy current path can be effectively blocked, reducing eddy current losses. Furthermore, the multiple segmented units 21 are spaced apart, increasing the heat dissipation area of ​​the segmented units 21, which is beneficial for heat dissipation. In addition, by forming a cooling channel 50 between the first frame 30 and the back iron 10, and by passing through the interval between two adjacent segmented units 21, the cooling channel 50 can directly cool each segmented unit 21 of each magnet unit 20 with oil after the cooling medium (hydraulic oil) is introduced into the cooling channel 50, thereby improving the heat dissipation efficiency of the rotor assembly and ensuring the stable operation of the axial flux motor.

[0038] It should be noted that in this embodiment, the number of magnet units 20 is set to 10, and each magnet unit 20 includes 5 segmented units 21 arranged radially at intervals. In other embodiments, the specific number of magnet units 20 and segmented units 21 within each magnet unit 20 can be adjusted according to actual needs, and this embodiment does not impose specific limitations.

[0039] Optionally, such as Figure 2As shown, the bottom of the inner cavity 14 is provided with multiple limiting grooves 101. The multiple limiting grooves 101 are evenly spaced along the circumference of the back iron 10. The number of limiting grooves 101 is the same as the number of magnet units 20. The shape of the limiting grooves 101 is adapted to the shape of the magnet units 20. Each magnet unit 20 is accommodated in the corresponding limiting groove 101. It should be noted that in the axial direction of the rotor assembly, the magnet units 20 are only partially embedded in the limiting grooves 101. The magnet units 20 are glued to the bottom of the limiting grooves 101 by adhesive. Since the magnet unit 20 is embedded in the limiting groove 101 of the back iron 10, the rotor assembly adopts an internal structure. Compared with the surface-mounted structure, the rotor magnetic circuit of the internal structure is asymmetrical, which creates the conditions for generating reluctance torque. Therefore, it can provide permanent magnet torque and reluctance torque at the same time. The permanent magnet torque and reluctance torque work together to output power. The field weakening control force is strong, and the back electromotive force can be adjusted through field weakening control. It is more suitable for a wide speed range and has better performance when running at high speed.

[0040] In an optional embodiment, such as Figure 4 As shown, the back iron 10 includes a disc body 11, a rotating shaft 12, and a retaining ring 13. The disc body 11 is arranged around the outer periphery of the rotating shaft 12, and the retaining ring 13 is arranged around the outer periphery of the disc body 11, together with the disc body 11 defining an inner cavity 14. In this embodiment, the disc body 11 adopts a stepped structure with a protruding boss in the middle, and the first frame 30 is sleeved on the boss of the disc body 11. Specifically, the magnet unit 20 and the first frame 30 are both located in the inner cavity 14. The outer peripheral surface of the magnet unit 20 abuts against the retaining ring 13, thereby achieving radial limiting of the magnet unit 20, providing radial support for the magnet unit 20, resisting the centrifugal force generated during rotation, and thus improving the stability of the rotor assembly.

[0041] In this embodiment, the rotating shaft 12, the disc body 11, and the retaining ring 13 are integrally formed. The integral forming process completes the forming of the entire part in one mold at a time, reducing the number of processes and material waste in the production process, thereby significantly reducing production costs and improving the stability of the structure and production efficiency.

[0042] like Figure 1 As shown, the surface of the first frame 30 facing away from the back iron 10 is flush with the end face of the magnet and the retaining ring 13. This makes the surface of the rotor assembly a flat plane, reducing wind friction loss at high speeds.

[0043] like Figure 3As shown, the cooling channel 50 includes an oil inlet straight flow channel 51, an oil outlet straight flow channel 52, and multiple annular flow channels 53. The multiple annular flow channels 53 are arranged coaxially along the radial direction of the back iron 10 and are arranged in a one-to-one correspondence with the interval between two adjacent segment units 21. Each annular flow channel 53 passes through the interval between two corresponding adjacent segment units 21. The oil inlet straight flow channel 51 and the oil outlet straight flow channel 52 are arranged circumferentially along the back iron 10 and both extend radially along the back iron 10. In this embodiment, the oil inlet straight flow channel 51 and the oil outlet straight flow channel 52 are arranged adjacent to each other and are blocked from each other. The oil inlet straight flow channel 51 and the oil outlet straight flow channel 52 are both connected to the multiple annular flow channels 53.

[0044] Furthermore, such as Figure 4 As shown, the rotating shaft 12 is provided with an external oil inlet hole 121 and an external oil outlet hole 122 extending along its axial direction. The boss of the disc body 11 is provided with an internal oil inlet hole 112 and an internal oil outlet hole 113 horizontally. One end of the internal oil inlet hole 112 is connected to the external oil inlet hole 121, and the other end of the internal oil inlet hole 112 is connected to the oil inlet straight flow channel 51. One end of the internal oil outlet hole 113 is connected to the external oil outlet hole 122, and the other end of the internal oil outlet hole 113 is connected to the oil outlet straight flow channel 52.

[0045] Combination Figure 3 and Figure 4 During heat dissipation, the cooling medium flows from the outer oil inlet 121 into the inner oil inlet 112, and then into the oil inlet straight flow channel 51. The cooling medium flowing in the oil inlet straight flow channel 51 can be quickly distributed to each annular flow channel 53 and flows clockwise in the annular flow channel 53. Then it flows into the oil outlet straight flow channel 52 and into the inner oil outlet 113, and finally flows out through the outer oil outlet 122. The oil flowing in the annular flow channel 53 can flow through the gap between two adjacent segment units 21, thereby efficiently and comprehensively cooling each segment unit 21 directly and improving the heat dissipation efficiency of the rotor assembly.

[0046] In this embodiment, the inlet straight flow channel 51 and the outlet straight flow channel 52 are formed on the first frame 30, and the annular flow channel 53 is formed by the first frame 30 and the disc body 11. There are four annular flow channels 53, one fewer than the number of segment units 21. In other optional embodiments, the annular flow channel 53 can also be adaptively adjusted according to the number of segment units 21, as long as the number of intervals between each segment unit 21 is the same, and no specific limitation is made here.

[0047] Optionally, such as Figure 4As shown, the bottom of the inner cavity 14 is also provided with multiple annular grooves 111. These annular grooves 111 are arranged coaxially and at intervals along the radial direction of the disk body 11. The depth of each annular groove 111 is greater than the depth of each limiting groove 101. Each limiting groove 101 is located on the path of the multiple annular grooves 111, meaning that each annular groove 111 passes through the bottom of each limiting groove 101. The annular grooves 111 form part of the annular flow channel 53; therefore, the number of annular grooves 111 is the same as the number of annular flow channels 53. Furthermore, by creating annular grooves 111 on the back iron 10, it is possible to block potentially large-area eddy current loops, confining the eddy currents to these narrow areas, thus weakening the eddy current intensity, reducing iron loss and eddy current loss, and decreasing the heat generated by the back iron 10.

[0048] like Figure 5 As shown, the first frame 30 includes an annular portion 31, multiple baffles 32, and multiple first annular ribs 33. The annular portion 31 is sleeved on the protrusion of the disc body 11. The multiple baffles 32 are evenly connected to the outer periphery of the annular portion 31 along the circumference. The number of baffles 32 is the same as the number of magnet units 20. Each baffle 32 is embedded between two adjacent magnet units 20. One of the baffles 32 has the aforementioned oil inlet straight flow channel 51 and oil outlet straight flow channel 52 on the side near the back iron 10. The multiple first annular ribs 33 are arranged coaxially at intervals along the radial direction of the annular portion 31 and are connected to each baffle 32 along the circumference. The number of first annular ribs 33 is the same as the number of annular flow channels 53. Each first annular rib 33 is embedded in the interval between two adjacent segment units 21.

[0049] Specifically, the baffle arm 32 is filled between two adjacent magnet units 20, with its lower surface fitting against the bottom of the inner cavity 14. The upper surface of the baffle arm 32 is flush with the upper surfaces of the segmented unit 21 and the baffle ring 13. The first annular rib 33 is filled between two adjacent segmented units 21, but not completely. The upper surface of the first annular rib 33 is flush with the upper surface of the segmented unit 21, and the distance between the lower surface of the first annular rib 33 and the bottom of the inner cavity 14 is two-thirds the thickness of the segmented unit 21, thus preserving a channel for the cooling medium to flow. Through the baffle arm 32 and the first annular rib 33, a closed cooling channel 50 can be formed axially, allowing the cooling oil to flow only circumferentially and not axially.

[0050] Optionally, the annular portion 31, multiple stop arms 32, and multiple first annular ribs 33 are integrally formed. This integral forming process reduces production steps and material waste by completing the entire part in one mold, thereby significantly reducing production costs and improving structural stability and production efficiency.

[0051] Specifically, such as Figure 6As shown, each baffle arm 32 includes multiple baffle units 321 arranged radially at intervals. Along the radial direction of the baffle arm 32, each first annular rib 33 is connected between two adjacent baffle units 321. An arc groove 322 is formed between two adjacent baffle units 321. The arc groove 322 and the annular groove 111 are arranged in a one-to-one correspondence. When the baffle arm 32 is embedded between two adjacent magnet units 20 and the first annular rib 33 is embedded between two adjacent segment units 21, the first annular rib 33, the arc groove 322 and the annular groove 111 together define an annular flow channel 53 that is closed in the axial direction.

[0052] Optionally, such as Figure 7 As shown, the rotor assembly also includes a second frame 40, which includes multiple second annular ribs 41. Each second annular rib 41 corresponds to an annular groove 111, and the second annular ribs 41 are embedded within the corresponding annular groove 111. By embedding the second frame 40 within each annular groove 111, the stress concentration within the groove caused by centrifugal force on the back iron 10 at high speeds can be reduced, thereby reducing the risk of the back iron 10 being damaged by centrifugal force and improving the overall rigidity of the rotor assembly. This makes the rotor assembly less prone to deformation under centrifugal force at high speeds, thus preventing it from affecting the oil circuit. Furthermore, the second annular ribs 41 can also divide the limiting groove 101 into radially spaced single grooves, each containing a segmented unit 21. Therefore, the second annular ribs 41 can also radially limit the segmented unit 21, preventing it from moving radially.

[0053] In one optional embodiment, the second annular rib 41 completely fills the annular groove 111, that is, the upper surface of the first annular rib 33 is flush with the bottom of the inner cavity 14. In this case, the first annular rib 33, the arc-shaped groove 322, and the second annular rib 41 together define an axially closed annular flow channel 53. Of course, in other optional embodiments, the second annular rib 41 may also fill a portion of the depth of the annular groove 111 along the axial direction of the rotor assembly, which is not specifically limited here.

[0054] Optionally, the back iron 10 is made of steel with magnetic and electrical properties, such as 45 steel. The first frame 30 and the second frame 40 are both made of non-magnetic and non-conductive composite materials, such as FR4, which have high structural strength.

[0055] The assembly process of the rotor assembly provided in this embodiment is as follows: First, each of the first annular ribs 33 of the first frame 30 is embedded into the corresponding annular groove 111 and fixed by adhesive. Then, each segment unit 21 is embedded into the corresponding limiting groove 101 and fixed by adhesive. Finally, the second frame 40 is embedded to form a complete rotor assembly and fixed by adhesive.

[0056] This embodiment also provides an axial flux motor, including at least one stator assembly and at least one rotor assembly, with the rotor assembly and stator assembly alternately distributed along the axial direction. The rotor assembly can be any of the aforementioned rotor assemblies, and all of these rotor assemblies have the aforementioned effects. The axial flux motor having these rotor assemblies also has the aforementioned effects, so they will not be described in detail here. It should be noted that the specific structure of the stator assembly is prior art and will not be described in detail here either.

[0057] Optionally, the axial flux motor can be a dual-stator single-rotor, single-stator single-rotor, single-stator dual-rotor, or multi-stator multi-rotor axial flux motor, without specific limitations.

[0058] It should be noted that the axial flux motor provided in this embodiment can be applied to electrical equipment. Optionally, the electrical equipment can be a vehicle, which can be a pure electric vehicle or a hybrid vehicle; this application does not impose any limitations. The axial flux motor can serve as a motor in a vehicle, used to output power to drive the wheels, for example, as a hub motor. The axial flux motor can also serve as a generator in a vehicle, generating electricity during vehicle operation to charge the vehicle's battery. Of course, in other optional embodiments, the electrical equipment may be other devices, which are not specifically limited here.

[0059] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A rotor assembly, characterized in that, The device includes a back iron (10), a first frame (30), and multiple magnet units (20). The back iron (10) has an inner cavity (14) on one side. The multiple magnet units (20) are evenly spaced in the inner cavity (14) along the circumference of the back iron (10). Each magnet unit (20) includes multiple segmented units (21) arranged radially spaced along the back iron (10). The first frame (30) is disposed in the inner cavity (14) and embedded between two adjacent magnet units (20) and two adjacent segmented units (21). The side of the first frame (30) close to the back iron (10) forms a cooling channel (50) with the back iron (10). The cooling channel (50) passes through the interval between two adjacent segmented units (21) and is used to introduce a cooling medium.

2. The rotor assembly according to claim 1, characterized in that, The bottom of the inner cavity (14) is provided with a plurality of limiting grooves (101). The plurality of limiting grooves (101) are evenly spaced along the circumference of the back iron (10). The number of limiting grooves (101) is the same as the number of magnet units (20). Each magnet unit (20) is housed in the corresponding limiting groove (101).

3. The rotor assembly according to claim 1, characterized in that, The back iron (10) includes a disc body (11), a rotating shaft (12) and a retaining ring (13). The disc body (11) is arranged around the outer periphery of the rotating shaft (12), and the retaining ring (13) is arranged around the outer periphery of the disc body (11) and together with the disc body (11) defines the inner cavity (14). The rotating shaft (12), the disc body (11) and the retaining ring (13) are integrally formed.

4. The rotor assembly according to claim 3, characterized in that, The surface of the first frame (30) facing away from the back iron (10) is flush with the end face of the magnet and the retaining ring (13).

5. The rotor assembly according to claim 3, characterized in that, The cooling channel (50) includes an oil inlet straight flow channel (51), an oil outlet straight flow channel (52), and multiple annular flow channels (53). The multiple annular flow channels (53) are arranged coaxially along the radial direction of the back iron (10) and are set in a one-to-one correspondence with the interval between two adjacent segment units (21). Each annular flow channel (53) passes through the interval between two corresponding adjacent segment units (21). The oil inlet straight flow channel (51) and the oil outlet straight flow channel (52) are arranged circumferentially along the back iron (10) and both extend radially along the back iron (10). The oil inlet straight flow channel (51) and the oil outlet straight flow channel (52) are both connected to the multiple annular flow channels (53).

6. The rotor assembly according to claim 5, characterized in that, The rotating shaft (12) is provided with an external oil inlet hole (121) and an external oil outlet hole (122) extending along its axial direction. The disc body (11) is provided with an internal oil inlet hole (112) and an internal oil outlet hole (113) horizontally. One end of the internal oil inlet hole (112) is connected to the external oil inlet hole (121), and the other end of the internal oil inlet hole (112) is connected to the oil inlet straight flow channel (51). One end of the internal oil outlet hole (113) is connected to the external oil outlet hole (122), and the other end of the internal oil outlet hole (113) is connected to the oil outlet straight flow channel (52).

7. The rotor assembly according to claim 5, characterized in that, The first frame (30) includes an annular portion (31), multiple baffles (32) and multiple first annular ribs (33). The multiple baffles (32) are uniformly connected to the outer periphery of the annular portion (31) along the circumference. The number of baffles (32) is the same as the number of magnet units (20). Each baffle (32) is embedded between two adjacent magnet units (20). The multiple first annular ribs (33) are arranged coaxially along the radial direction of the annular portion (31) and connected to each baffle (32) along the circumference. The number of first annular ribs (33) is the same as the number of annular channels (53). Each first annular rib (33) is embedded in the interval between two adjacent segment units (21).

8. The rotor assembly according to claim 7, characterized in that, The bottom of the inner cavity (14) is provided with a plurality of annular grooves (111), and the plurality of annular grooves (111) are arranged coaxially at intervals along the radial direction of the disc body (11); each of the baffle arms (32) includes a plurality of baffle units (321) arranged at intervals along its radial direction, and each of the first annular ribs (33) is connected between two adjacent baffle units (321) along the radial direction of the baffle arm (32), and an arc groove (322) is formed between two adjacent baffle units (321), and the arc groove (322) and the annular groove (111) are arranged in a one-to-one correspondence, and the first annular rib (33), the arc groove (322) and the annular groove (111) together define the annular flow channel (53).

9. The rotor assembly according to claim 8, characterized in that, The rotor assembly further includes a second frame (40), which includes a plurality of second annular ribs (41). The second annular ribs (41) correspond one-to-one with the annular grooves (111), and the second annular ribs (41) are embedded in the corresponding annular grooves (111).

10. An axial flux motor, characterized in that, It includes at least one stator assembly and at least one rotor assembly as described in any one of claims 1-9, wherein the rotor assembly and the stator assembly are alternately distributed along the axial direction.

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