Motor assembly and axial flux motor

Abstract

The invention relates to the technical field of motors, in particular to a motor assembly and an axial flux motor. The motor assembly at least comprises a first bearing, a rotating shaft, and a first stator assembly, a second stator assembly and a third stator assembly which are sequentially arranged along the axial direction of the rotating shaft. The first stator assembly, the second stator assembly and the third stator assembly each comprise a shell and a stator located in the shell, the two sides of the stator of the second stator assembly are each provided with a rotor, and the stators are printed circuit board stators; the shells of the stator assemblies are detachably connected. The first bearing comprises a first shell; a first channel surrounding the rotating shaft is arranged in the first shell; a plurality of rolling bodies are arranged in the first channel; the first bearing is in rolling connection with the rotating shaft through a plurality of rolling bodies; and the outer wall of the first shell is sleeved with the stator of the second stator assembly. The motor assembly provided by the invention has the characteristics of simple structure, convenient assembly and high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor component and an axial flux motor. Background Art

[0002] At present, high-efficiency and environmentally friendly and energy-saving motors have become the consensus of the development plan of the motor industry around the world, making micro motors with high power density a current research hotspot. In particular, hollow cup motors, DC brushless motors and servo motors in micro motors all have higher power density, which conforms to the concept of green environmental protection and low carbon. In the future, they will gradually penetrate into fields with high power consumption and high frequency of use. And as industrial robots, household appliances and other equipment tend to be more energy-efficient, miniaturized and intelligent, motors, as an important part of actuators, have higher and higher requirements for lightweight, miniaturization and response speed. This has further promoted the continuous development of micro motors in the direction of high efficiency, lightweight and low cost, and thus developed axial flux motors.

[0003] Compared with traditional motors (such as coreless motors), axial flux motors have higher power density and efficiency, more compact structure, and lighter weight, which makes it possible to develop in fields with higher requirements on weight and space, such as robots, drones, and automobiles. However, the existing axial flux motors still need to be improved in terms of structural accuracy, size, reliability, and installation complexity. Summary of the invention

[0004] In order to solve the technical problems of low structural precision, large size, poor reliability, and installation complexity of the above-mentioned existing axial flux motor, the present application discloses a motor assembly, which at least includes a first bearing, a rotating shaft, and a first stator assembly, a second stator assembly, and a third stator assembly arranged in sequence along the axial direction of the rotating shaft;

[0005] The first stator assembly includes a first housing and a first stator located in the first housing;

[0006] The second stator assembly includes a second housing, and a first rotor, a second stator, and a second rotor located in the second housing and sequentially spaced apart along the axial direction of the rotating shaft;

[0007] The third stator assembly includes a third housing and a third stator located in the third housing;

[0008] The first stator, the second stator and the third stator are all printed circuit board stators;

[0009] The first shell, the second shell and the third shell are detachably connected;

[0010] The first bearing comprises a first shell; a first channel surrounding the rotating shaft is arranged in the first shell; a plurality of rolling bodies are arranged in the first channel; the first bearing is rollingly connected to the rotating shaft through the plurality of rolling bodies; and the outer wall of the first shell is sleeved with the second stator.

[0011] Optionally, the second shell includes a first end surface and a second end surface opposite to each other;

[0012] A first notch is provided on the first end surface and / or the connecting end surface of the first shell, so that a first notch is formed after the first end surface is connected to the connecting end surface of the first shell;

[0013] A second notch is provided on the second end surface and / or the connecting end surface of the third shell, so that a second notch is formed after the second end surface is connected to the connecting end surface of the third shell;

[0014] The first notch and the second notch are both located on the mounting surfaces of the first shell, the second shell and the third shell.

[0015] Optionally, the width of the first notch, the second notch and the third notch is 0.2 to 0.5 mm;

[0016] The widths of the first notch, the second notch and the third notch are 3.5 to 11 mm. Optionally, a third notch and a conductive member are provided on the mounting surface of the second housing;

[0017] The winding of the first stator is electrically connected to the conductive member through the first flexible circuit board and through the first notch;

[0018] The winding of the second stator is electrically connected to the conductive member through the second flexible circuit board and through the third notch;

[0019] The winding of the third stator is electrically connected to the conductive member through the third flexible circuit board and through the second notch.

[0020] Optionally, a second channel is provided on the rotating shaft;

[0021] The plurality of rolling bodies are arranged in a concave channel formed by the first channel and the second channel.

[0022] Optionally, the rotating shaft includes a first end and a second end opposite to each other;

[0023] The first end portion passes through the first housing and is used to connect with the driven member;

[0024] The second end passes through the second rotor and is located in the second housing or the third housing.

[0025] Optionally, the printed circuit board stator comprises a support plate, a plurality of magnetic conductive parts and stacked printed circuit boards;

[0026] A first mounting hole is provided in the middle of the support plate, and the first mounting hole is connected to the rotating shaft through a shaft sleeve;

[0027] The support plate is also provided with a plurality of second mounting holes surrounding the first mounting hole, each of the second mounting holes is connected to one end of a corresponding magnetic conductive member; the other end of the magnetic conductive member is provided with an epitaxial wafer;

[0028] The printed circuit board is provided with a plurality of through holes; each of the through holes is sleeved with a corresponding magnetic conductive member; three-phase conductors are arranged on the printed circuit to form a stator winding;

[0029] The gap distance between adjacent epitaxial wafers is smaller than the gap distance between adjacent magnetic conductive parts.

[0030] Optionally, the second shell is provided with heat dissipation holes.

[0031] On the other hand, the present application further discloses an axial flux motor, which includes the above-mentioned motor assembly.

[0032] Optionally, further comprising a second bearing;

[0033] The inner ring of the second bearing is connected to the rotating shaft;

[0034] The outer ring of the second bearing is connected to the first stator.

[0035] The motor assembly provided in the embodiment of the present application at least includes a first bearing, a rotating shaft, and a first stator assembly, a second stator assembly, and a third stator assembly arranged in sequence along the axial direction of the rotating shaft; the first stator assembly includes a first housing and a first stator located in the first housing; the second stator assembly includes a second housing, and a first rotor, a second stator, and a second rotor located in the second housing and arranged in sequence along the axial direction of the rotating shaft; the third stator assembly includes a third housing and a third stator located in the third housing; the first stator, the second stator, and the third stator are all printed circuit board stators; the first housing, the second housing, and the third housing are detachably connected; the first bearing includes a first housing; a first channel surrounding the rotating shaft is provided in the first housing; a plurality of rolling bodies are provided in the first channel; the first bearing is rollingly connected to the rotating shaft through a plurality of rolling bodies; and the outer wall of the first housing is sleeved with the second stator. In this way, it is not only convenient to assemble the motor, but also has the advantages of simple overall structure and high shaft strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A cross-sectional view of an exemplary motor assembly of the present application;

[0038] Figure 2 A three-dimensional diagram of an exemplary motor assembly of the present application;

[0039] Figure 3 A cross-sectional view of another motor assembly exemplified in the present application;

[0040] Figure 4 This is a schematic diagram of the structure of an exemplary rotor of the present application;

[0041] Figure 5 This is a schematic diagram of a connection between a support plate and a magnetic conductive member exemplified in the present application;

[0042] Figure 6 An exemplary magnetic circuit diagram of the present application;

[0043] Figure 7 A three-dimensional diagram of an exemplary printed circuit board stator of the present application;

[0044] Figure 8 This is a schematic diagram of the structure of an exemplary shaft sleeve of the present application;

[0045] Fig. 9 This is a cross-sectional view of an exemplary axial flux motor of the present application.

[0046] The following is a supplementary description of the attached drawings:

[0047] 1-rotating shaft; 101-second channel; 2-first bearing; 201-first housing; 202-first channel; 203-rolling element; 3-first stator assembly; 301-first housing; 302-first stator; 4-second stator assembly; 401-second housing; 402-second stator; 403-first rotor; 404-second rotor; 5-third stator assembly; 501-third housing; 502-third stator; 6-first notch; 7-second notch; 8- The third notch; 9-conductive part; 10-first flexible circuit board; 11-second flexible circuit board; 12-third flexible circuit board; 13-support plate; 1301-first mounting hole; 1302-second mounting hole; 14-magnetic conductive part; 15-printed circuit board; 16-epitaxial wafer; 17-heat dissipation hole; 18-second bearing; 19-magnetic steel frame; 20-magnetic steel; 21-three-phase lead wire; 22-magnetic conductive sheet; 23-sleeve; 2301-glue guide groove; 24-high thermal conductive glue. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0050] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all sub-ranges between a minimum of 1 and a maximum of 10. Exemplary sub-ranges of ranges 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0051] See also Figure 1 , which is a cross-sectional view of an exemplary motor assembly of the present application. The motor assembly at least includes a first bearing 2, a rotating shaft 1, and a first stator assembly 3, a second stator assembly 4, and a third stator assembly 5 arranged in sequence along the axial direction of the rotating shaft 1; the first stator assembly 3 includes a first housing 301 and a first stator 302 located in the first housing 301; the second stator assembly 4 includes a second housing 401, and a first rotor 403, a second stator 402, and a second rotor 404 located in the second housing 401 and arranged in sequence along the axial direction of the rotating shaft 1; the third stator assembly 5 includes a third housing 501 and a first rotor 403, a second stator 402, and a second rotor 404 located in the third housing 501. The third stator 502; the first stator 302, the second stator 402 and the third stator 502 are all printed circuit board stators; the first shell 301, the second shell 401 and the third shell 501 are detachably connected; the first bearing 2 includes a first shell 201; a first channel 202 surrounding the rotating shaft 1 is provided in the first shell 201; a plurality of rolling bodies 203 are provided in the first channel 202; the first bearing 2 is rollingly connected to the rotating shaft 1 through the plurality of rolling bodies 203; the outer wall of the first shell 201 is sleeved with the second stator 402.

[0052] In the embodiment of the present application, after positioning and connecting the first shell 301, the second shell 401 and the third shell 501, they can be connected by ultrasonic wave / laser welding / adhesive, etc., so as to ensure the positioning accuracy and structural strength. Since the three-phase lead-out accessories of the three stators have been assembled before the shell is assembled, that is, the three-phase lead-out accessories are located on the outside of the second shell 401, when the first stator 302 and the second stator 402 are respectively installed with the corresponding three-phase lead-out accessories, the three-phase lead-out accessories can be easily seen, so as to connect them with the corresponding stator windings, which can improve the assembly efficiency.

[0053] The first stator 302 and the third stator 502 can be symmetrically distributed on both sides of the second housing 401, so that during processing and manufacturing, the first stator 302 and the third stator 502 can adopt the same stator structure, thereby reducing the processing cost of the entire motor and improving the processing efficiency.

[0054] By designing the shell to be spliced, it has a very high compactness and solves the problem that the three-phase lead-out accessories of the stator winding are difficult to lead out. Subsequently, slots can be designed on the mounting surfaces of the first shell 301, the second shell 401 and the third shell 501 respectively so that the three-phase lead-out accessories can be led out from the slots, and interference with the rotor when the motor is running can be avoided, which may cause motor failure.

[0055] In the embodiment of the present application, the first shell 301 is fixedly connected to the first stator 302, the second shell 401 is fixedly connected to the second stator 402, and the third shell 501 is fixedly connected to the third shell 501, thereby ensuring the stability and electrical reliability of the entire stator assembly structure.

[0056] The first shell 301, the second shell 401 and the third shell 501 in the present application can be an integral cavity, that is, there is no step design inside, and the end faces of the first shell 301 and the third shell 501 can be used as positioning and mounting surfaces, thereby improving the radial accuracy of the shaft system structure, running more smoothly, and having better NVH.

[0057] In one possible implementation, see Figure 2 , the second shell 401 is provided with heat dissipation holes 17, which effectively reduce the temperature rise. Optionally, the heat dissipation holes 17 can be specifically provided on the second shell 401, and in the area adjacent to the rotor, so as to have a better heat dissipation effect. The heat dissipation holes 17 can also be provided on the first shell 301 or the second shell 401 as needed, and can also be provided on any two of the three shells. The size and number of the specific heat dissipation holes 17 can be set as needed, and are not limited here.

[0058] The second housing 401 includes a first end surface and a second end surface opposite to each other; see Figure 3In a feasible embodiment, a first notch is provided on the first end surface, and the connecting end surface of the first shell 301 is a flat surface, so that the first end surface and the connecting end surface of the first shell 301 can form a first notch 6 after being connected; a second notch is provided on the second end surface, and the connecting end surface of the third shell 501 is a flat surface, so that the second end surface and the connecting end surface of the third shell 501 can form a second notch 7 after being connected. In a feasible embodiment, a first notch is provided on both the first end surface and the connecting end surface of the first shell 301, so that the first notch 6 can be formed after being connected to the connecting end surface of the first shell 301; a second notch is provided on both the second end surface and the connecting end surface of the third shell 501, so that the second notch 7 can be formed after being connected to the connecting end surface of the second end surface and the connecting end surface of the third shell 501. In a feasible embodiment, the first end face is a flat surface, and a first notch is provided on the connecting end face of the first housing 301, so that a first notch 6 can be formed after the first end face is connected to the connecting end face of the first housing 301; the second end face is a flat surface, and a second notch is provided on the connecting end face of the third housing 501, so that a second notch 7 can be formed after the second end face is connected to the connecting end face of the third housing 501. In other embodiments, it is also possible to have a notch only on the connecting end face of the first end face and the third housing 501, or to have a notch on any three or two of the first end face, the second end face, the connecting end face of the first housing 301, and the connecting end face of the third housing 501, without limitation, as long as the first notch 6 and the second notch 7 can be formed in the end. The first notch 6 and the second notch 7 are both located on the mounting surfaces of the first housing 301, the second housing 401, and the third housing 501. Therefore, the three-phase lead-out accessories can be centrally arranged on the mounting surface to avoid being led out through other peripheral surfaces of the housing, further improving the structural compactness of the motor and facilitating its miniaturization.

[0059] In one possible implementation, see Figure 3 , the mounting surface of the second housing 401 is provided with a third notch 8 and a conductive member 9; the winding of the first stator 302 is electrically connected to the conductive member 9 through the first flexible circuit board 10 through the first notch 6; the winding of the second stator 402 is electrically connected to the conductive member 9 through the second flexible circuit board 11 through the third notch 8; the winding of the third stator 502 is electrically connected to the conductive member 9 through the second notch 7 through the third flexible circuit board 12. Such an arrangement can greatly improve the axial compactness of the motor assembly.

[0060] The conductive member 9 can be formed integrally with the second housing 401 to ensure the connection strength between the two.

[0061] The winding of each stator is led out through a corresponding flexible circuit board and then connected to the conductive member 9, so that the entire lead-out structure is compact and highly reliable. The flexible circuit board has good bending and stretching properties and a very narrow axial dimension, so that the three-phase line lead-out accessories (i.e., the flexible circuit board) can be designed into a flat structure, which reduces its axial dimension while ensuring its current-carrying capacity.

[0062] In the embodiment of the present application, the sizes of the first notch 6, the second notch 7 and the third notch 8 can be determined according to the size of the flexible circuit board. Optionally, the thickness d of the first, second and third flexible circuit boards can be 0.1 to 0.3 mm, and the width L can be 3 to 10 mm; then the width of the first notch 6, the second notch 7 and the third notch 8 can be 0.2 to 0.5 mm, that is, the width can be d+0.1 to d+0.2 mm, and the length can be L+0.5 to L+1 mm, that is, 3.5 to 11 mm. Thus, while ensuring the convenience of installation of the flexible circuit board, it can also avoid the interference of the flexible circuit board with the rotor when the motor is running, and also improve the axial compactness of the motor, further improving the miniaturization of the motor.

[0063] For a feasible implementation, please continue to refer to Figure 3 , a second channel 101 is provided on the rotating shaft 1; the plurality of rolling bodies 203 are provided in a concave channel formed by the first channel 202 and the second channel 101. The rolling body 203 is directly connected to the rotating shaft 1 and the first housing 201, and has the characteristics of simple structure and small radial dimension, so that the radial width of the rotating shaft 1 can be designed to be larger, and the deflection of the rotating shaft 1 and the stability of the overall motor are improved. Optionally, two rows of second channels 101 can be provided on the rotating shaft 1, and the first housing 201 is also provided with two rows of first channels 202 that cooperate with the two rows of second channels 101, so as to further improve the shaft strength of the motor. Specifically, the number of the first channels 202 and the number of the second channels 101 mentioned above are related to the width of the second stator 402 and the required strength requirements. The wider the width of the second stator 402, the more rows of channels can be designed to improve the shaft strength of the motor.

[0064] In a feasible implementation, the rotating shaft 1 includes a first end and a second end opposite to each other; the first end passes through the first housing 301 for connection with a driven member; the second end passes through the second rotor 404 and is located in the second housing 401 or the third housing 501. The entire rotating shaft 1 has the characteristics of short length and radial width, thereby improving its load bearing capacity.

[0065] The embodiment of the present application connects the rotating shaft 1 with the second stator 402 by setting the above-mentioned first bearing 2 on the rotating shaft 1, thereby greatly reducing the force arm from the output end to the bearing end, reducing the load on the bearing, and reducing the length of the rotating shaft 1 by more than 1 / 3. This method of directly connecting the rotating shaft 1 with the outer shell of the first bearing 2 through the rolling element 203 not only increases the dynamic and static load bearing capacity and improves the dimensional accuracy, but also increases the outer diameter of the rotating shaft 1, improves the strength and rigidity of the rotating shaft 1, reduces the deflection, and the manufacturing cost of the rotating shaft 1 and the motor assembly cost can also be reduced.

[0066] In the embodiment of the present application, the structures of the first rotor 403 and the second rotor 404 may be the same, which is optional. Figure 4 , which is a schematic diagram of the structure of an exemplary rotor of the present application. The first rotor 403 and the second rotor 404 may both include a magnetic steel frame 19 and a plurality of magnetic steels 20, the polarities of adjacent magnetic steels 20 are different, the magnetic steel frame 19 is made of non-magnetic material, and an assembly hole is provided in the middle of the magnetic steel frame 19, and the assembly hole of the magnetic steel frame 19 is fixedly connected to the rotating shaft 1. Optionally, the magnetic steel frame 19 and the rotating shaft 1 may be interference fit or connected by bonding. Optionally, a groove is provided on the connecting side of the magnetic steel frame 19 and the magnetic steel 20, and the two are connected by bonding, and the design of the groove can further improve the bonding strength between the two.

[0067] In one possible implementation, see Figure 3 and Figure 5 The printed circuit board stator includes a support plate 13, a plurality of magnetic conductive parts 14 and a stacked printed circuit board 15; a first mounting hole 1301 is provided in the middle of the support plate 13, and the first mounting hole 1301 is connected to the rotating shaft 1 through a sleeve 23; a plurality of second mounting holes 1302 surrounding the first mounting hole 1301 are also provided on the support plate 13, and each of the second mounting holes 1302 is connected to one end of a corresponding magnetic conductive part 14; an epitaxial wafer 16 is provided at the other end of the magnetic conductive part 14; a plurality of through holes are provided on the printed circuit board 15; each of the through holes is sleeved with a corresponding magnetic conductive part 14; three-phase conductors are arranged on the printed circuit to form a stator winding; the gap distance between adjacent epitaxial wafers 16 is smaller than the gap distance between adjacent magnetic conductive parts 14. Thus, not only can the magnetic leakage problem be avoided, but also the jitter problem during the operation of the motor can be effectively reduced.

[0068] See also Figure 6, which shows an exemplary magnetic circuit diagram of the present application. The two adjacent magnetic steels 20 in the first rotor 403 are respectively called magnetic steel A1 and magnetic steel A2, and the polarities of magnetic steel A1 and magnetic steel A2 are opposite. The two adjacent magnetic steels 20 in the second rotor 404 are respectively called magnetic steel B1 and magnetic steel B2, and the polarities of magnetic steel B1 and magnetic steel B2 are opposite. The two adjacent magnetic conductive parts in the first stator 302 are respectively called magnetic conductive parts C1 and magnetic conductive parts C2, and the two adjacent magnetic conductive parts in the second stator 402 are respectively called magnetic conductive parts D1 and magnetic conductive parts D2. The two adjacent magnetic conductive parts in the sub-302 are respectively called magnetic conductive parts E1 and magnetic conductive parts E2. The specific magnetic circuit can be formed by magnetic conductive parts C2-magnetic steel A2-magnetic conductive parts D2-magnetic steel B2-magnetic conductive parts E2-support plate 13-magnetic conductive parts E1-magnetic steel B1-magnetic conductive parts D1-magnetic steel A1-magnetic conductive parts C1-support plate 13-magnetic conductive parts C2, forming a magnetic circuit closed loop. In fact, when passing through the magnetic conductive parts E2, a magnetic circuit passing through the support plate 13 to another adjacent magnetic conductive parts 14 is also formed. Therefore, when the epitaxial wafer 16 is not provided, due to the large interval between adjacent magnetic conductive parts 14, the magnetic field between adjacent magnetic conductive parts 14 will change greatly, and the magnetic force will also change greatly, which will cause the motor to vibrate more when running.

[0069] In the embodiment of the present application, the design of the epitaxial wafer 16 makes the interval between adjacent magnetic conductive parts 14 smaller, so that the magnetic field change between the two is gradual, and the force change is also gradual, thereby reducing the jitter of the motor during operation.

[0070] For details, please refer to Figure 5 , assuming that the gap distance between adjacent epitaxial wafers is b0, the setting of the gap distance is mainly related to the cogging torque T cog The ultimate purpose is to suppress the cogging torque. The relationship between the two can be expressed as the following formula:

[0071]

[0072] Where, z represents the number of slots in the motor; L a represents the axial length of the stator; μ0 represents the vacuum permeability; R S Indicates the inner radius of the stator; R r represents the outer radius of the rotor; k is an integer greater than or equal to 1; α represents the angle between the center line of a magnetic conductive component and the center line of the permanent magnet; N P =2p / GCD(z, 2P); GCD represents the greatest common divisor; p represents the number of motor pole pairs, and 2p represents the number of magnetic conductive parts; Represents the Fourier decomposition coefficient of the square of the relative air gap flux density; B is the Fourier decomposition coefficient of the square of the air gap flux density generated by the magnetic steel of the rotor.

[0073] To simplify the analysis, we can use the low-order air gap relative permeability The relationship between b0 and b1 shows that by properly selecting the gap distance b0 between adjacent epitaxial wafers, As close to zero as possible to achieve the purpose of suppressing the cogging torque, that is:

[0074]

[0075] Among them, h m represents the thickness of the magnetic steel; δ represents the gap width between the stator and the rotor; θ represents the angle, and specifically, θ=0 represents the centerline position of the permanent magnet. Therefore, b0 can be reasonably determined to obtain the best rotation effect of the motor.

[0076] The structure of the magnetic conductive member 14 with the epitaxial wafer 16 is relatively complex, and the processing is relatively complex. Therefore, in order to further simplify the stator structure, after the multi-layer printed circuit board 15 is installed on the multiple magnetic conductive members 14, the magnetic conductive sheet 22 can be covered on the surface of the printed circuit board 15, which can also reduce the jitter during the operation of the motor. Since the magnetic conductive member 14 can be a columnar structure, it has the advantages of simple processing and simple installation. Optionally, the magnetic conductive sheet 22 is provided with a plurality of third mounting holes that are sleeved with the magnetic conductive member 14. Optionally, the third mounting hole of the magnetic conductive sheet 22 and the magnetic conductive member 14 can be fixedly connected by filling glue. Optionally, the through hole on the printed circuit board 15 and the magnetic conductive member 14 can be an interference fit, or can be bonded by glue.

[0077] It should be noted that the structures of the above-mentioned stators can be the same or different, for example, the stator can be a stator with an epitaxial wafer 16 or a stator with a magnetic conductive sheet 22. In order to further reduce the motor cogging torque and achieve a very small torque amplitude, the first sub-stator and the third sub-stator can be set as stators with epitaxial wafers 16, and the second sub-stator can be set as a stator with a magnetic conductive sheet 22, and then the slots of the three can be optimized.

[0078] In the present application, please refer to Figure 7 The first mounting hole 1301 of the printed circuit board stator is connected to the rotating shaft 1 through the sleeve 23. The sleeve 23 is a non-magnetic material, so as to avoid the magnetic field from magnetizing the bearing steel material inside the bearing and the interference of the magnetic field on the magnetic coding signal. Compared with designing the sleeve 23 and the support plate 13 as an integrated structure, the sleeve 23 and the support plate 13 in this solution are separate structures, which can reduce the difficulty of processing. Optionally, the side wall of the sleeve 23 is provided with a glue guide groove 2301 to enhance the bonding strength between the sleeve 23 and the printed circuit board 15, and improve the anti-torsion and anti-pulling performance of the entire stator. The installation gaps of the printed circuit stator can be sealed by filling with high thermal conductivity glue 24 to ensure the reliability of strength. The use of glue eliminates the tolerance accumulation and ensures the assembly accuracy.

[0079] In the field of micro motors, due to the thin wire diameter, many turns, and small size of the motor core, traditional winding is a great difficulty for motor manufacturing. Not only is the cost high, but also due to the thin wire, it is easy to break, the defect rate is high, and the development cycle is long; and the thin wire diameter and many turns lead to irregular winding, one is to cause unbalanced three-phase inductance, which makes control difficult, and the second is to cause gaps between wires, poor heat dissipation, high winding temperature, and limited output torque. Moreover, in traditional axial flux motors, the printed circuit board 15 in the stator is mostly solid design, and the number of superimposed layers is limited, resulting in the number of winding turns cannot be very high; the magnetic path of the magnetic lines of force inside the motor is magnetic steel 20, air gap, printed circuit board 15, air gap, magnetic steel 20. Since the copper and insulating materials inside the printed circuit board 15 are non-magnetic materials, the axial height of the printed circuit board 15 is also regarded as part of the air gap, which causes the air gap to be much higher than that of conventional motors, resulting in the magnetic flux passing through the winding to be much lower than that of conventional motors. Therefore, for applications requiring high torque / power, it cannot meet the requirements. The embodiment of the present application uses the magnetic conductive member 14 as the magnetic circuit component, which can ensure a minimum air gap, reduce magnetic circuit losses, and increase the torque / power density by more than 2.5 times compared to motors of the same size.

[0080] It should be noted that the number of stators and rotors included in the present solution is not limited to the above-mentioned exemplary case, and may also be a structure composed of multiple of the above-mentioned configurations, or may be other configurations including the above-mentioned configurations, such as setting another stator and rotor on one side of the first stator 302, and setting another stator and rotor on one side of the third stator 502. However, it is necessary to ensure that the overall configuration is a symmetrical structure, and a stator is provided on both sides of each rotor, so that the motor can achieve a higher torque density and avoid damage to the rotating shaft 1.

[0081] The motor assembly provided in the embodiment of the present application, by setting a first bearing 2 on the rotating shaft 1, designs the rotating shaft 1 and the bearing into an integrated bearing structure, thereby improving the load capacity of the shaft system, reducing the length of the rotating shaft 1, and improving the accuracy and strength of the entire shaft system. The separate design of multiple stators and corresponding housings can facilitate the assembly of the three-phase lead-out accessories of the stator winding and improve the assembly efficiency of the entire motor assembly. Since the inner diameter processing accuracy of the printed circuit board 15 is low, each stator is connected to the rotating shaft 1 through a magnetically isolated sleeve 23 and positioned by tooling to ensure the assembly accuracy with the housing mating surface, and the accumulated dimensional deviation is eliminated by using a high thermal conductivity potting glue, and the printed circuit board 15 and the sleeve 23 are connected by a high thermal conductivity glue 24. The glue is used to make a structural connection to ensure the reliability of strength, and the glue is used to eliminate the accumulated tolerance to ensure the assembly accuracy; and the gaps between the various components in each stator can be achieved by using a high thermal conductivity potting glue to connect the support plate 13, the magnetic conductive part 14, the printed circuit board 15, the sleeve 23, etc. into a whole, which not only ensures the reliability of strength, but also ensures the heat dissipation performance of the entire stator assembly, and can improve the power / torque density of the motor.

[0082] An embodiment of the present application discloses an axial flux motor, which includes the motor assembly described above.

[0083] In one possible implementation, see Fig. 9 The axial flux motor further includes a second bearing 18; the inner ring of the second bearing 18 is connected to the rotating shaft 1; the outer ring of the second bearing 18 is connected to the first stator 302. Thus, the load strength of the shaft system can be further improved. Optionally, the second bearing 18 includes an inner shell, a plurality of rolling elements 203 and a second outer shell, a rolling channel is formed between the second outer shell and the inner shell, a plurality of rolling elements 203 are assembled in the rolling channel, and the inner shell and the rotating shaft 1 are interference fit or bonded, so that the rotating shaft 1 can rotate relative to the first stator 302.

[0084] The axial flux motor may further include a control unit; the control unit may be disposed on the end surface of the third housing 501 to collect and control the rotation angle of the motor.

[0085] The following is an example of an assembly scheme for an axial flux motor: Fig. 9, a first rotor 403 and a second rotor 404 are obtained by assembling a plurality of magnetic steels 20 onto a magnetic steel frame 19; the support plate 13 is first assembled with the shaft sleeve 23, and then assembled with the printed circuit board 15 and the magnetic conductive member 14 in sequence, and then the support plate 13, the shaft sleeve 23, the printed circuit board 15 and the magnetic conductive member 14 are formed into a whole by using a gluing process to obtain a first stator 302, a second stator 402 and a third stator 502. The second flexible circuit board 11 is connected to the three-phase lead-out pads of the second stator 402, and then covered with insulating glue to ensure mechanical strength and insulation reliability, and then the first stator 302 is assembled with the first housing 301. During assembly, the second flexible circuit board 11 is led out through the third notch 8 to ensure the angle matching requirements, and the second stator assembly 4 is formed.

[0086] The second stator 402 in the second stator assembly 4 is press-fitted to the first bearing 2 on the rotating shaft 1 through the sleeve 23 (specifically, it can be bonded or interference fit), and then the first rotor 403 and the second rotor 404 are press-fitted on both sides of the second stator 402 respectively.

[0087] By connecting the first flexible circuit board 10 with the three-phase lead-out pad of the first stator 302, and then covering it with insulating glue to ensure mechanical strength and insulation reliability, the first stator 302 and the first shell 301 are assembled, and the tooling is used to perform angle positioning during assembly to ensure the angle matching requirements, forming the stator components on the left and right sides (i.e., the first stator component 3 and the third stator component 5). If the load end needs to be assembled with a bearing, the second bearing 18 can be assembled between the first stator 302 and the rotating shaft 1; the tooling is used to position during the press-fitting process to ensure the position accuracy of the three stator components, and then ultrasonic / laser welding / adhesive and other forms are used to connect the adjacent shells to ensure the strength and connection reliability of the entire motor structure. After assembly, the first, second and third flexible circuit boards are welded to the conductive member 9 on the second shell 401 to ensure electrical conduction and mechanical reliable connection, and then the three-phase lead-out wires 21 are respectively connected to the corresponding conductive member 9 by soldering, and all solder joints are covered with insulating glue to ensure mechanical strength and insulation reliability.

[0088] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A motor assembly, characterized in that: At least comprises a first bearing, a rotating shaft, and a first stator assembly, a second stator assembly and a third stator assembly sequentially arranged along the axial direction of the rotating shaft; The first stator assembly includes a first housing and a first stator located in the first housing; The second stator assembly includes a second housing, and a first rotor, a second stator, and a second rotor located in the second housing and sequentially spaced apart along the axial direction of the rotating shaft; The third stator assembly includes a third housing and a third stator located in the third housing; The first stator, the second stator and the third stator are all printed circuit board stators; The first shell, the second shell and the third shell are detachably connected; The first bearing comprises a first shell; a first channel surrounding the rotating shaft is arranged in the first shell; a plurality of rolling bodies are arranged in the first channel; the first bearing is rollingly connected to the rotating shaft through the plurality of rolling bodies; and the outer wall of the first shell is sleeved with the second stator.

2. The motor assembly according to claim 1, characterized in that: The second housing includes a first end surface and a second end surface that are opposite to each other; A first notch is provided on the first end surface and / or the connecting end surface of the first shell, so that a first notch is formed after the first end surface is connected to the connecting end surface of the first shell; A second notch is provided on the second end surface and / or the connecting end surface of the third shell, so that a second notch is formed after the second end surface is connected to the connecting end surface of the third shell; The first notch and the second notch are both located on the mounting surfaces of the first shell, the second shell and the third shell.

3. The motor assembly according to claim 2, characterized in that: A third notch and a conductive member are provided on the mounting surface of the second housing; The winding of the first stator is electrically connected to the conductive member through the first flexible circuit board and through the first notch; The winding of the second stator is electrically connected to the conductive member through the second flexible circuit board and through the third notch; The winding of the third stator is electrically connected to the conductive member through the third flexible circuit board and through the second notch.

4. The motor assembly according to claim 3, characterized in that: The width of the first notch, the second notch and the third notch is 0.2 to 0.5 mm; The widths of the first notch, the second notch, and the third notch are 3.5 to 11 mm.

5. The motor assembly according to claim 1, characterized in that: The rotating shaft is provided with a second channel; The plurality of rolling bodies are arranged in a concave channel formed by the first channel and the second channel.

6. The motor assembly according to claim 1, characterized in that The rotating shaft includes a first end and a second end that are opposite to each other; The first end portion passes through the first housing and is used to connect with the driven member; The second end passes through the second rotor and is located in the second housing or the third housing.

7. The motor assembly according to any one of claims 1 to 6, characterized in that: The printed circuit board stator comprises a support plate, a plurality of magnetic conductive parts and stacked printed circuit boards; A first mounting hole is provided in the middle of the support plate, and the first mounting hole is connected to the rotating shaft through a shaft sleeve; The support plate is also provided with a plurality of second mounting holes surrounding the first mounting hole, each of the second mounting holes is connected to one end of a corresponding magnetic conductive member; the other end of the magnetic conductive member is provided with an epitaxial wafer; The printed circuit board is provided with a plurality of through holes; each of the through holes is sleeved with a corresponding magnetic conductive member; three-phase conductors are arranged on the printed circuit to form a stator winding; The gap distance between adjacent epitaxial wafers is smaller than the gap distance between adjacent magnetic conductive parts.

8. The motor assembly according to claim 7, characterized in that The second shell is provided with heat dissipation holes.

9. An axial flux motor, characterized in that: Comprising a motor assembly as described in any one of claims 1-8.

10. The axial flux motor according to claim 9, characterized in that: Also including a second bearing; The inner ring of the second bearing is connected to the rotating shaft; The outer ring of the second bearing is connected to the first stator.

Images