An ultra-thin axial motor stator structure with a stamped back plate and a disc motor

Abstract

An ultra-thin axial motor stator structure with a stamped back plate and a disc motor. The stator structure includes a back plate, a coil bearing support, and bearings. The back plate is provided with annularly arrayed coil holes, and coils are installed in the coil holes. A bearing support installation hole is provided at the center position of the back plate, and the bearing support is press-fitted into the bearing support installation hole. The bearing support is a hollow structure, and two bearings are provided in the hollow structure of the bearing support. The rotating shaft is inserted into the two bearings; the back plate is a hollow circular ring structure, and the inner circular surface of the central circular ring of the back plate is in tight fit with the rotating shaft. The hollow part of the back plate serves to fix the coils and is used to replace the wire grooves; the back plate is processed by stamping. Since the back plate is processed by stamping and the material used is electrolytic galvanized steel sheet, compared with the processing method and material of the conventional stator core, the material is cheaper and the processing method is easier, which can reduce the cost of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of disc motors, and particularly to an ultra-thin axial motor stator structure with a stamping back plate and a disc motor. Background Art

[0002] Due to the axial magnetic field design, both the stator and rotor of a disc motor are disc structures, with relatively large radial dimensions and small axial dimensions, large moment of inertia, and stable operation. Compared with traditional radial magnetic field motors, it has the characteristics of short axial dimension, small volume, light weight, and high power density. At the same time, in order to improve the utilization rate of permanent magnetic materials, a Halbach array is mostly used to improve the use efficiency of magnetic materials. Disc motors are widely used in drive motors for transportation equipment and servo systems, and have broad market application prospects. However, the magnetic field strength at the gap between permanent magnets on existing disc motors is relatively weak, resulting in a low power density of the motor. To achieve the same power, a larger volume of disc motor is required for the motor speed. Existing disc motors use a tooth structure, which is large in volume and has low motor power. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, an object of the present invention is to provide an ultra-thin axial motor stator structure with a stamping back plate and a disc motor. By providing auxiliary permanent magnets between the permanent magnets, the magnetic field strength on the air gap side between the rotor and the stator is greatly improved, which can effectively reduce the volume of the motor and increase the power density of the motor. The sinusoidal distribution degree of the air gap magnetic field is relatively high, and the harmonic content is small, which can further improve the stability of the motor. At the same time, it can also weaken the magnetic field strength on the non-air gap side, playing a role of self-electromagnetic shielding, and is more suitable for occasions with strict requirements for electromagnetic interference.

[0004] In a first aspect, the present application provides a coreless ultra-thin axial motor stator structure, including a back plate, coils, a bearing support, and bearings. The back plate is provided with annularly arrayed coil holes, the coils are installed in the coil holes, a bearing support installation hole is provided at the center position of the back plate, the bearing support is press-fitted into the bearing support installation hole, the bearing support is a hollow structure, and two bearings are provided in the hollow structure of the bearing support 7. The rotating shaft 1 is inserted into the two bearings; the back plate is a hollow circular ring structure, and the inner circular surface of the central circular ring of the back plate is closely fitted with the rotating shaft. The hollow part of the back plate serves to fix the coils and is used to replace the wire groove; the back plate uses a stamping process.

[0005] In some embodiments, the material of the back plate can be electrolytic zinc-coated steel sheet, or non-oriented silicon steel sheet or ordinary steel sheet; the shape of the coils on the back plate can be fan-shaped, diamond-shaped, trapezoidal or triangular.

[0006] In some embodiments, the bearing can be an oil-impregnated bearing, a ball bearing, or a hydraulic bearing.

[0007] In a second aspect, the present application provides a coreless ultra-thin axial disc motor, comprising a rotor structure and the stator structure described in the first aspect. The rotor structure includes a rotating shaft, a rotor disc, and permanent magnets. The permanent magnets are trapezoidal, and there is a certain gap between every two permanent magnets; the rotor disc integrally forms the rotating shaft and the permanent magnets through an injection molding process to form the rotor structure; the stator structure and the rotor structure are fixed by the cooperation of the rotating shaft (1) and the back plate (6-2), and the air gap can be adjusted.

[0008] In some embodiments, the coreless ultra-thin axial disc motor further includes auxiliary permanent magnets. The permanent magnets are distributed in an annular array, and a plurality of auxiliary permanent magnets are provided at the gaps between adjacent permanent magnets. The magnetization directions of the permanent magnets and the auxiliary permanent magnets form a certain angle. The permanent magnets and the auxiliary permanent magnets are embedded at the bottom of the rotor disc, and the rotating shaft 1 passes through the center position of the rotor disc and is integrally formed therewith.

[0009] In some embodiments, the included angle range of the magnetization directions of the permanent magnets and the auxiliary permanent magnets is 45-135°.

[0010] In some embodiments, the included angle of the magnetization directions of the permanent magnets and the auxiliary permanent magnets is 45°, 90°, or 135°.

[0011] In some embodiments, 1-3 auxiliary permanent magnets are provided at the gaps between adjacent permanent magnets.

[0012] In some embodiments, the shape of the permanent magnets is trapezoidal, fan-shaped, or rectangular, and the shape of the auxiliary permanent magnets is rectangular, oval, or cylindrical.

[0013] In some embodiments, the permanent magnets and the auxiliary permanent magnets are one of sintered neodymium iron boron magnets, bonded neodymium iron boron magnets, ferrite magnets, injection magnets, or rubber magnets.

[0014] In the present invention, 1. The disc motor has an ultra-thin structure with a height of 6 mm. The material of the back plate is changed from a magnetic conductive material to a PCB material, and the stator tooth structure is cancelled. At the same time, when the included angle of the magnetization directions of the permanent magnets and the auxiliary permanent magnets is 90°, the magnetic field arrangement adopts a Halbach array to achieve the purpose of improving the motor efficiency and rotation accuracy. Auxiliary permanent magnets are provided between the permanent magnets, and the magnetic field intensity on the air gap side is greatly improved, so that the volume of the motor can be effectively reduced and the power density of the motor can be increased.

[0015] 2. An auxiliary permanent magnet is provided between the permanent magnets, which greatly enhances the magnetic field intensity on the air-gap side between the rotor and the stator. This can effectively reduce the volume of the motor and increase the power density of the motor. The sinusoidal distribution degree of the air-gap magnetic field is relatively high and the harmonic content is small, which can further improve the stability of the motor. At the same time, it can also weaken the magnetic field intensity on the non-air-gap side, playing a role of self-electromagnetic shielding, and is more suitable for occasions with strict requirements for electromagnetic interference.

[0016] 3. The ultra-thin structure of the motor will reduce the maximum value of the leakage magnetic flux of the motor. At the same time, the Halbach array is adopted for the arrangement of the permanent magnets and the auxiliary permanent magnets, which can increase the main magnetic flux passing through the winding coils of the motor to the state when there is a toothed structure. At the same time, the motor is free from the influence of cogging torque caused by the stator teeth, and finally achieves the purpose of improving the motor efficiency and rotation accuracy.

[0017] 4. The rotating shaft and the rotor disc are integrally cast, and then the permanent magnets and the auxiliary permanent magnets are embedded at the bottom of the rotor disc. In this way, the four components form an integral structure, reducing the motor assembly process during assembly, improving the production efficiency of the motor, and reducing the production cost of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0019] Figure 1 is an exploded structural schematic diagram of a coreless ultra-thin axial disc motor according to an embodiment proposed by the present invention;

[0020] Figure 2 is a structural schematic diagram of the assembled coreless ultra-thin axial disc motor according to an embodiment proposed by the present invention;

[0021] Figure 3 is an exploded structural schematic diagram of the rotor structure of a coreless ultra-thin axial motor according to an embodiment proposed by the present invention;

[0022] Figure 4 is a structural schematic diagram of the back plate of a coreless ultra-thin axial motor according to an embodiment proposed by the present invention;

[0023] Figure 5 is an exploded structural schematic diagram of the stator structure of a coreless ultra-thin axial motor according to an embodiment proposed by the present invention;

[0024] Figure 6 is an exploded structural schematic diagram of a coreless ultra-thin axial disc motor according to another embodiment proposed by the present invention.

[0025] In the figure: 1. Rotating shaft; 2. Rotor disk; 3. Permanent magnet; 3-1. Auxiliary permanent magnet; 4. Coil; 6-1. Back plate; 7. Bearing support; 8. Bearing. Detailed implementation mode

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0027] Embodiment 1:

[0028] As Figure 1 , Figure 2 shown, the disc motor structure in the embodiment of the present invention includes a rotor structure and a stator structure.

[0029] As Figure 3 shown, the rotor structure includes a rotating shaft 1, a rotor disk 2, and a permanent magnet 3. Among them, the permanent magnet 3 is trapezoidal, and there is a certain gap between every two permanent magnets 3. The rotor disk 2 integrally forms the rotating shaft 1 and the permanent magnet 3 by injection molding, which can effectively prevent the permanent magnet from shifting in position during the rotation of the rotor, ensuring the reliability of the motor. Reduce the motor assembly process and lower the labor cost.

[0030] As Figure 4 shown, the stator structure includes a coil 4, a back plate 6-1, a bearing support 7, and a bearing 8. The coil 4 is fixed on the back plate 6-1 by injection molding or casting and other methods, which can play a role in fixing the coil and also enhance the insulation between the coil and the back plate. The back plate can enhance the air-gap magnetic field strength under the condition of only generating weak cogging torque, and can also enhance the structural strength of the rotor structure. The outer cylindrical surface of the bearing support 7 is fixed to the inner cylindrical surface of the back plate 6-1 by a tight fit. The bearing 8 is pressed into the two ends of the center of the bearing support 7. A step can be designed in the middle of the inner cylindrical surface of the bearing support 7 to fix the two end bearings without collision and friction, reducing unnecessary mechanical losses.

[0031] The back plate 6-1 is a hollow circular ring structure, and the inner cylindrical surface of the central circular ring of the back plate 6-1 is in close fit with the outer ring of the bearing 8 support. The hollow part of the back plate 6-1 is for fixing the coil and is used to replace the wire groove.

[0032] The center of the rotor disk 2 is a circular ring structure, and the inner cylindrical surface of the central circular ring of the rotor disk 2 is in close fit with the rotating shaft 1.

[0033] There is a groove at the bottom of the rotating shaft 1, and the groove is fixedly matched with the bearing to fix the air-gap size between the stator and rotor structures.

[0034] In some embodiments, the rotor disk 2 uses an injection molding method to integrally form and fix the permanent magnet 3 and the rotating shaft 1, ensuring that the permanent magnet does not shift in position during the rotation of the rotor part. This reduces the motor assembly process and lowers the labor cost.

[0035] As Figure 5 shown, the back plate uses a stamping processing and forming method, and the material used is electrolytic galvanized steel sheet. Compared with the processing method and material of the conventional stator core, the material is cheaper and the processing method is easier, which can reduce the cost of the motor.

[0036] The back plate material is magnetically conductive, but the height of the teeth on the back plate is lower than the height of the coil, greatly reducing the cogging torque. According to reasonable calculations, by designing winding coils with different cross-sections, turns, and heights, the vibration and noise of the motor can be reduced, and higher control accuracy can be achieved.

[0037] The teeth on the back plate are of a hollow structure, and the blank position in the middle of the teeth can accommodate position sensing components such as hall, making full use of the internal space of the motor and enabling miniaturization of the motor.

[0038] The rotor structure is closely fitted with the bearing 8 in the stator structure through the groove on the rotating shaft 1, and the air gap size can be controlled by adjusting the groove position or width and adding gaskets.

[0039] Embodiment 2:

[0040] Referring to Figure 6 , a coreless ultra-thin axial motor rotor structure proposed by the present invention includes a rotor disk 2, a rotating shaft 1, and a permanent magnet 3, and further includes an auxiliary permanent magnet 3-1. The permanent magnets 3 are distributed in an annular array, and a plurality of auxiliary permanent magnets 3-1 are provided at the gaps between adjacent permanent magnets 3. The magnetization directions of the permanent magnets 3 and the auxiliary permanent magnets 3-1 form a certain angle. The permanent magnets 3 and the auxiliary permanent magnets 3-1 are embedded at the bottom of the rotor disk, and the rotating shaft 1 passes through the center of the rotor disk 2 and is integrally formed with it.

[0041] The function of the stator tooth structure is to guide the magnetic flux generated by the permanent magnet to pass through the winding coil, reducing the leakage magnetic flux of the motor, and improving the torque and efficiency of the motor. However, the existence of the stator tooth structure will also have a negative impact on the motor, causing cogging torque and reducing the rotation accuracy of the motor. Canceling the stator tooth structure will reduce the main magnetic flux passing through the winding coil of the motor and increase the leakage magnetic flux, resulting in a decrease in the motor efficiency. However, the ultra-thin structure of the motor will reduce the maximum value of the leakage magnetic flux of the motor. At the same time, by adding the auxiliary permanent magnet 3-1, the main magnetic flux passing through the winding coil of the motor can be increased to the state when there is a tooth structure. At the same time, the influence of the cogging torque brought by the stator teeth of the motor is reduced, and finally the purpose of improving the motor efficiency and rotation accuracy is achieved.

[0042] It is also possible to integrally form and fix the permanent magnet 3 and the rotating shaft to ensure that the permanent magnet 3 does not shift in position during the rotation of the rotor part.

[0043] The back plate is made of PCB material to reduce the weight of the motor and achieve the light weight of the motor.

[0044] The included angle range of the magnetization directions of the permanent magnet 3 and the auxiliary permanent magnet 3-1 is 45-135°.

[0045] When the included angle of the magnetization directions of the permanent magnet 3 and the auxiliary permanent magnet 3-1 is 90°, the magnetic field arrangement of the permanent magnet 3 and the auxiliary permanent magnet 3-1 is a Halbach array, which can increase the main magnetic flux passing through the winding coil to the state when there is a toothed structure. The magnetic field intensity on the air gap side is greatly improved, so that the volume of the motor can be effectively reduced and the power density of the motor can be increased. The sinusoidal distribution degree of the air gap magnetic field is relatively high and the harmonic content is small, which can further improve the stability of the motor

[0046] One to three auxiliary permanent magnets 3-1 are arranged at the gaps between adjacent permanent magnets 3. Preferably one.

[0047] The shape of the permanent magnet 3 is trapezoidal, sector-shaped or rectangular, and the shape of the auxiliary permanent magnet 3-1 is rectangular, oval or cylindrical.

[0048] The permanent magnet 3 and the auxiliary permanent magnet 3-1 are one of sintered neodymium iron boron magnets, bonded neodymium iron boron magnets, ferrite magnets, injection-molded magnets or rubber magnets. The same material is used for both in the selection, and sintered neodymium iron boron magnets are preferred.

[0049] The present invention proposes a stator structure of a coreless ultra-thin axial motor, a stator structure capable of installing the above rotor structure, including a back plate 6-1, a coil 4, a bearing support 7 and a bearing 8. The back plate 6-1 is provided with annularly arrayed coil holes, the coil 4 is installed in the coil holes, a bearing support installation hole is provided at the center position of the back plate 6-1, the bearing support 7 is press-fitted into the bearing support installation hole, the bearing support 7 is a hollow structure, and two bearings 8 are provided in the hollow structure of the bearing support 7. The rotating shaft 1 is inserted into the two bearings 8.

[0050] The back plate 6-1 is a hollow circular ring structure, and the inner circular surface of the central ring of the back plate 6-1 is in close fit with the outer ring of the bearing support 7. The hollow part of the back plate serves to fix the coil and is used to replace the wire groove.

[0051] The coil 4 is fixed on the back plate 6-1 through an injection molding process. The outer cylindrical surface of the bearing support 7 and the inner cylindrical surface of the back plate 6-1 are fixed together by a tight fit method. The bearings 8 are pressed into the two ends of the center of the bearing support 7. A step can be designed in the middle of the inner cylindrical surface of the bearing support 7 to fix the two end bearings without collision and friction, reducing unnecessary mechanical losses. A distance is left between the two bearings 8 to improve the stability of the rotating shaft 1 mounted on the two bearings 8.

[0052] A groove is provided at the bottom of the rotating shaft 1. The groove is fixedly matched with the bearing 8 to fix the air gap size between the stator and rotor discs. The rotor structure is tightly matched with the bearing 8 in the stator structure through the groove on the rotating shaft 1. The air gap size can be controlled by adjusting the position or width of the groove and adding gaskets.

[0053] The present invention proposes a coreless ultra-thin axial disc motor, which includes the above-mentioned rotor structure and the disc motor with the above-mentioned stator structure. The disc motor has an ultra-thin structure with a height of 6 mm. The material of the back plate is changed from a magnetic conductive material to a PCB material, and the stator tooth structure is cancelled. Auxiliary permanent magnets are provided between the permanent magnets, and the magnetic field strength on the air gap side is greatly improved, so that the volume of the motor can be effectively reduced and the power density of the motor can be improved.

[0054] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An ultra-thin axial motor stator structure with a stamped backplane, characterized in that: It includes a backplane (6-1), a coil (4), a bearing support (7) and a bearing (8). The backplane (6-1) is provided with annularly arrayed coil holes, the coil (4) is installed in the coil holes, a bearing support installation hole is provided at the center position of the backplane (6-1), the bearing support (7) is press-fitted and inserted into the bearing support installation hole. The bearing support (7) is a hollow structure, and two bearings (8) are provided in the hollow structure of the bearing support (7). A rotating shaft (1) is inserted into the two bearings (8); the backplane is a hollow circular ring structure, and the inner circular surface of the central circular ring of the backplane is in tight fit with the rotating shaft; the hollow part of the backplane serves to fix the coil and is used to replace the wire groove; the backplane (6-1) uses a stamping process; the material of the backplane (6-1) is electrolytic galvanized steel sheet, non-oriented silicon steel sheet or ordinary steel sheet; the shape of the coil on the backplane (6-1) is fan-shaped, diamond-shaped, trapezoidal or triangular; the bearing (8) is an oil-impregnated bearing, a ball bearing or a hydraulic bearing.

2. An ultra-thin axial disc motor with a stamped backplane, comprising the stator structure and the rotor structure described in claim 1. The rotor structure includes a rotating shaft (1), a rotor disc (2), and a permanent magnet (3). The permanent magnet (3) is trapezoidal, and there is a certain gap between every two permanent magnets (3); the rotor disc (2) integrally forms the rotating shaft (1) and the permanent magnet (3) through an injection molding process to form a rotor structure; the stator structure and the rotor structure are fixed by the cooperation of the rotating shaft (1) and the backplane (6-2), and the air gap can be adjusted.

3. The ultra-thin axial disc motor with a stamped backplane according to claim 2, characterized in that: The permanent magnets (3) are distributed in an annular array, and a plurality of auxiliary permanent magnets (3-1) are provided at the gaps between adjacent permanent magnets (3). The magnetization directions of the permanent magnets (3) and the auxiliary permanent magnets (3-1) form a certain angle. The permanent magnets (3) and the auxiliary permanent magnets (3-1) are embedded at the bottom of the rotor disc, and the rotating shaft (1) passes through the center position of the rotor disc (2) and is integrally formed with it.

4. The ultra-thin axial disc motor with a stamped backplane according to claim 2, characterized in that: The included angle range of the magnetization directions of the permanent magnets (3) and the auxiliary permanent magnets (3-1) is 45-135°.

5. The ultra-thin axial disc motor with a stamped backplane according to claim 4, characterized in that: The included angle of the magnetization directions of the permanent magnets (3) and the auxiliary permanent magnets (3-1) is 45°, 90° or 135°.

6. The ultra-thin axial disc motor with a stamped backplane according to claim 2, characterized in that: 1-3 auxiliary permanent magnets (3-1) are provided at the gaps between adjacent permanent magnets (3).

7. The ultra-thin axial disc motor with a stamped backplane according to claim 2, characterized in that: The permanent magnets (3) and the auxiliary permanent magnets (3-1) are one of sintered neodymium iron boron magnets, bonded neodymium iron boron magnets, ferrite magnets, injection magnets or rubber magnets.

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