Assembling method of micro motor and micro motor structure thereof

Abstract

The present application relates to the technical field of micro motor production, in particular to a micro motor assembling method and a micro motor structure thereof, which comprises the following steps: step S1, press the stator assembly into the shell with a preset phase angle, so that the wedge-shaped protrusion and the annular clamping groove generate an axial force locking; step S2, after cooling the bearing seat by liquid nitrogen, press the rotor shaft, and form an interference fit after returning to normal temperature; step S3, when installing the end cover, apply axial compression to the shape memory alloy ring, heat it to trigger radial expansion; step S4, run the motor at rated speed, and use centrifugal force to make the buffer pad at the bottom of the bearing seat plastically deform to fit in the shell. The present application realizes self-tightening of the micro motor in the vibration environment through the synergistic effect of geometric constraints and material properties, ensures that the structure of the micro motor can remain stable for a long time and is not easy to loosen, and has strong structural stability.

Description

Technical Field

[0001] This invention relates to the field of micro motor manufacturing technology, and in particular to a method for assembling a micro motor and its micro motor structure. Background Technology

[0002] As a core component of precision drive systems, micro motors are widely used in aerospace, medical devices, and micro-robotics. With applications expanding to high-frequency vibration and high-impact environments, traditional micro motors are prone to problems such as stator assembly displacement, bearing loosening, and end-cap seal failure under long-term vibration loads, leading to performance degradation and even structural damage. Current technologies typically use mechanical connections such as interference fits, elastic clips, or threaded fasteners to fix components. However, these rigid connections are prone to stress concentration and fatigue microcracks under the accumulation of alternating vibration energy, making it difficult to maintain long-term stability. For example, the assembly of the stator and housing often uses equal-depth grooves and protrusions, with a single axial locking force that cannot adapt to dynamic load changes under vibration conditions, leading to accumulated phase angle shifts. The assembly between the bearing housing and the rotor shaft is also prone to material brittleness or uneven interference distribution. Furthermore, existing buffer materials have insufficient damping performance and cannot effectively dissipate high-frequency vibration energy through plastic deformation, causing micro-displacement resonance in the bearing assembly and affecting the stability of the assembled motor. Summary of the Invention

[0003] This invention addresses the problems of existing technologies by providing a method for assembling a micro motor and its micro motor structure. The ingenious design achieves self-tightening of the micro motor under vibration through the synergistic effect of geometric constraints and material properties in the assembly and connection of the stator assembly, housing, bearing housing, rotor shaft, and end cover. The phase assembly of the gradually deepening annular groove with the wedge-shaped stator, combined with the vibration energy dissipation compensated by the thermal deformation of the shape memory alloy ring during end cover assembly, ensures that the micro motor structure can remain stable for a long time under long-term vibration, is not easy to loosen, and has strong structural stability.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] The present invention provides a method for assembling a micro motor, which includes the following steps: Step S1, pressing the stator assembly into the housing at a preset phase angle, so that the wedge-shaped protrusion and the annular groove generate an axial component force to lock it;

[0006] Step S2: After cooling the bearing housing with liquid nitrogen, press-fit the rotor shaft and restore it to room temperature to form an interference fit;

[0007] Step S3: When installing the end cap, apply axial compression to the shape memory alloy ring and heat it until radial expansion is triggered;

[0008] Step S4: Run the motor at the rated speed and use centrifugal force to plastically deform the buffer pad at the bottom of the bearing housing so that it fits into the housing.

[0009] In step S2, the bearing housing is cooled to -196°C with liquid nitrogen, and the rotor shaft is pressed in at a speed of 0.5 mm / s and a pressing pressure of 50 MPa. After returning to normal temperature, an interference fit is formed between the bearing housing and the rotor shaft.

[0010] In step S2, the tapered bearing housing is completely immersed in liquid nitrogen, and the cooling rate is controlled by a non-uniform gradient. The method for non-uniform gradient control is as follows:

[0011] When cooling the conical surface region of the tapered bearing housing, the cooling rate is 50℃ / min; when cooling the bottom region of the tapered bearing housing, the cooling rate is 30℃ / min; the cooling time t is calculated based on the workpiece mass, using the formula: t = 0.05m 1.2 Where t is the cooling time and m is the mass of the workpiece.

[0012] In step S3, when installing the end cap, axial compression is applied to the shape memory alloy ring, and it is heated to 80-100°C to trigger radial expansion.

[0013] In step S3, when installing the end cap, axial compression is applied to the shape memory alloy ring, and when cooled to 20°C, the shape memory alloy ring shrinks radially by 0.12%.

[0014] In step S2, the bearing housing is cooled with liquid nitrogen and then subjected to low-temperature tempering at 150°C for 2 hours.

[0015] In step S2, when the bearing housing is cooled by liquid nitrogen, the bearing housing is positioned on a rotary table, and the rotary table drives the bearing housing to rotate at a constant speed in the liquid nitrogen.

[0016] The present invention also provides a micro motor structure formed according to the micro motor assembly method described above, which includes a housing, a stator assembly, a rotor shaft, a bearing housing, and an end cover. The inner wall of the housing is provided with an annular groove, the depth of which gradually changes circumferentially. The outer edge of the stator assembly is provided with a wedge-shaped protrusion that engages with the annular groove. The outer surface of the wedge-shaped protrusion is covered with a viscoelastic damping layer. The rotor shaft is press-fitted into the bearing housing, which is tapered and has a corrugated buffer pad at its bottom. The upper end of the housing is provided with an opening. A shape memory alloy ring is embedded in the lower outer periphery of the end cover. The end cover is installed on the upper end of the housing and is used to close the opening. After the end cover is installed on the upper end of the housing, the end cover is heat-treated so that the shape memory alloy ring generates a radial preload and abuts and locks against the inner wall of the housing.

[0017] The viscoelastic damping layer is a silicone-graphene composite material with a thickness of 0.1-0.3 mm and a loss factor ≥0.5.

[0018] The inner wall of the outer shell is also provided with multiple elastic buckles at equal intervals. The elastic buckles are arranged in a cantilever beam structure and the ends of the elastic buckles are provided with hemispherical protrusions.

[0019] The beneficial effects of this invention are:

[0020] This invention is ingeniously designed. Through the assembly and connection of the stator assembly, housing, bearing housing, rotor shaft, and end cover, the micro motor achieves self-tightening under vibration environment through the synergistic effect of geometric constraints and material properties. The phase assembly of the wedge-shaped stator with the annular groove of gradually varying depth, combined with the vibration energy dissipation compensated by the thermal deformation of the shape memory alloy ring during end cover assembly, ensures that the micro motor can maintain long-term structural stability under long-term vibration, is not easy to loosen, and has strong structural stability. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for assembling a micro motor according to the present invention.

[0022] Figure 2 This is an exploded view of a micro motor structure according to the present invention.

[0023] exist Figures 1 to 2 The reference numerals in the figures include:

[0024] 1. Housing; 2. Stator assembly; 3. Rotor shaft; 4. Bearing housing; 5. End cover; 6. Annular groove; 7. Wedge-shaped protrusion; 8. Corrugated buffer pad; 9. Shape memory alloy ring; 10. Elastic buckle; 11. Hemispherical protrusion. Detailed Implementation

[0025] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention. The present invention will be described in detail below with reference to the accompanying drawings.

[0026] Example 1

[0027] Embodiment 1 of this application provides a method for assembling a micro motor, such as... Figure 1As shown, it includes the following steps: Step S1, pressing the stator assembly into the housing at a preset phase angle, so that the wedge-shaped protrusion and the annular groove generate an axial component force locking (the axial component force is 15N), and the depth of the annular groove is set gradually; Step S2, pressing the rotor shaft after cooling the bearing housing with liquid nitrogen, and forming an interference fit after returning to room temperature; Step S3, applying axial compression to the shape memory alloy ring when installing the end cover, and heating it to trigger radial expansion; Step S4, running the motor at the rated speed for 30 minutes, using centrifugal force to cause the buffer pad at the bottom of the bearing housing to undergo plastic deformation so that it fits into the housing; wherein, the buffer pad is a corrugated buffer pad. Specifically, this invention is ingeniously designed. Through the synergistic effect of geometric constraints and material properties, the micro motor achieves self-tightening under vibration by assembling and connecting the stator assembly, housing, bearing housing, rotor shaft, and end cover. The phase assembly of the gradually deepening annular groove with the wedge-shaped stator, combined with the vibration energy dissipation compensated by the thermal deformation of the shape memory alloy ring during end cover assembly, ensures that the micro motor can maintain structural stability under long-term vibration, is not easy to loosen, and has strong structural stability.

[0028] In Embodiment 1 of this application, in step S2, the bearing housing is cooled to -196°C with liquid nitrogen, and the rotor shaft is press-fitted at a speed of 0.5 mm / s and a pressing pressure of 50 MPa. After returning to room temperature, an interference fit is formed between the bearing housing and the rotor shaft. In step S2, when cooling the bearing housing with liquid nitrogen, the bearing housing is positioned on a rotary table, which drives the bearing housing to rotate uniformly within the liquid nitrogen. This uniform rotation ensures consistent contact between the liquid nitrogen and the bearing housing, guaranteeing a temperature difference of <5°C between the surfaces of the bearing housing. Preferably, an annular nozzle is provided within the liquid nitrogen cooling chamber, and the inner wall of the annular nozzle has multiple equally spaced nozzle holes. Furthermore, in the liquid nitrogen cooling chamber, two-phase nitrogen gas is injected into the cooling chamber through the nozzle holes of the annular nozzle, with the injection pressure controlled at 0.15 MPa to reduce the risk of cold impact cracking.

[0029] In Embodiment 1 of this application, the bearing housing is tapered and made of stainless steel or other alloy material; in step S2, the tapered bearing housing is completely immersed in liquid nitrogen, and the cooling rate is controlled by a non-uniform gradient; the non-uniform gradient control method is: when cooling the tapered surface area of ​​the tapered bearing housing, the cooling rate is 50℃ / min; under this setting, it is beneficial to enhance the material shrinkage efficiency;

[0030] When cooling the bottom area of ​​the tapered bearing housing, the cooling rate is 30℃ / min. Under this setting, it is beneficial to reduce the stress concentration at the bottom of the tapered bearing housing, so that the bottom of the bearing housing fits better with the bottom of the inner wall of the housing during press fitting.

[0031] The cooling time t for cooling the bearing housing is calculated based on the workpiece mass, using the formula: t = 0.05m. 1.2 Where t is the cooling time (min) and m is the workpiece mass (kg).

[0032] In Embodiment 1 of this application, when pressing the rotor shaft into the bearing housing, a staged pressing operation can be adopted. After the bearing housing cools, it is pressed into the rotor shaft at a staged speed of 0.5 mm / s, specifically in three stages:

[0033] Initial stage (when the rotor shaft press-fit stroke is 0-0.2mm): speed 0.3mm / s. Under this setting, sudden cold shrinkage of the bearing housing can be avoided, and a slow adaptation effect can be achieved.

[0034] Main pressing stage (when the rotor shaft pressing stroke is 0.2-0.45mm): speed 0.6mm / s. Under this setting, it is beneficial to ensure the interference fit between the rotor shaft and the bearing housing.

[0035] Final pressing stage (when the rotor shaft pressing stroke is 0.45-0.5mm): speed 0.2mm / s. Under this setting, it is beneficial to eliminate residual stress between the rotor shaft and the bearing housing and reduce the stress concentration factor to 1.8.

[0036] In Embodiment 1 of this application, the aforementioned graded pressing operation ensures reliable and stable pressing of the rotor shaft and bearing housing, preventing sudden changes in temperature contraction and ensuring the interference fit between them. This also eliminates residual stress, resulting in a better pressing effect. To detect the interference fit, a temperature recovery monitoring system (using infrared temperature monitoring and sensor monitoring technologies) is used. Once the temperature returns to normal, an interference fit (interference of -0.03mm) is formed between the rotor shaft and bearing housing. Real-time monitoring of the axial displacement between the rotor shaft and bearing housing (when the axial displacement is <±1.2μm) indicates a reliable pressing effect.

[0037] In this embodiment, during step S3, when installing the end cap, axial compression is applied to the shape memory alloy ring, and radial expansion is triggered by heating to 80-100℃. Specifically, during step S3, when installing the end cap, axial compression is applied to the shape memory alloy ring, and upon cooling to 20℃, the shape memory alloy ring radially shrinks by 0.12%. The shape memory alloy ring is a Ni-Ti-Cu-V alloy ring. Axial compression is applied to the Ni-Ti-Cu-V alloy ring, and radial expansion (0.25% strain) is triggered by heating to 90℃. Dual-modal compensation: radial shrinkage of 0.12% upon cooling to -20℃ achieves temperature-adaptive pre-tightening; pre-tightening force fluctuation <5% (-40~120℃ operating conditions). This embodiment introduces a shape memory alloy ring (Ni-Ti-Cu system), which triggers radial expansion (0.25% strain) through heat treatment, real-time compensating for axial wear, and pre-tightening force fluctuation <5%.

[0038] In this embodiment, the buffer pad is made of silicone-carbon nanotube composite material, which forms a micro-fold structure after plastic deformation to enhance damping performance.

[0039] Example 2

[0040] In Embodiment 2 of this application, in step S2, the bearing housing is cooled with liquid nitrogen and then subjected to low-temperature tempering; the process steps are as follows:

[0041] Temperature rise control:

[0042] After natural rewarming and liquid nitrogen cooling, the bearing housing must be removed from the cryogenic chamber (cooling chamber) and allowed to naturally warm to room temperature (25°C) in the air. It is forbidden to directly temper before reaching room temperature to avoid cracking due to excessive temperature difference. Surface treatment: wipe off the frost on the surface and immediately spray with rust-preventive oil (such as phosphate ester rust inhibitor) to prevent oxidation.

[0043] Tempering parameter settings:

[0044] The tempering temperature should be controlled at 160-180℃ (for high-carbon alloy steels such as bearing steel); if the material is stainless steel or a molybdenum / chromium alloy, the temperature can be appropriately reduced to 150-170℃.

[0045] For single bearing housings, the heat preservation time is 2 hours to ensure that residual stress is fully released. For batch processing, the heat preservation time is extended by 0.5 hours for every 50% increase in the furnace load (e.g., 3 hours for 200% furnace load).

[0046] Tempering procedure:

[0047] Preheat the equipment and tempering furnace to the target temperature (±5℃) to avoid uneven heating of the workpiece;

[0048] The temperature is increased in stages, using a two-stage heating method. In the first stage, the temperature is increased to 100℃ at a rate of 5℃ / min; in the second stage, the temperature is increased to the target temperature at a rate of 3℃ / min.

[0049] Gas control: Nitrogen gas is introduced into the tempering furnace for protection, and the oxygen content is ≤0.5% to prevent surface oxidation and decarburization.

[0050] The cooling method is to cool the furnace to below 80°C after tempering before removing it to avoid secondary stress caused by rapid cooling.

[0051] Performance testing includes checking surface hardness (HV 700~750) and retained austenite content (≤5%) to ensure microstructure stability.

[0052] After the above tempering process, and through multiple experiments, the following technical comparison table is obtained:

[0053] heating rate Single rate (5℃ / min) Two-stage temperature control (5→3℃ / min) Oxygen content control Not mandatory (high risk of oxidation) ≤0.5% (Nitrogen protection) Residual austenite 8～12％ ≤5％ Batch processing efficiency It takes 3 hours to fill the furnace to 100% capacity. 200% furnace load can be achieved in just 3 hours

[0054] The tempering process of this application, through the synergistic effect of stepped temperature control, nitrogen protection and precise holding time, can eliminate more than 90% of the residual stress caused by liquid nitrogen cooling, while improving the toughness of the material by 15-20%.

[0055] In this embodiment of the application, the core purpose of introducing nitrogen into the tempering furnace during the bearing housing tempering process is to control the gas environment inside the furnace and prevent harmful reactions such as oxidation and decarburization of the material at high temperatures. Specifically, its functions include: preventing surface oxidation, inhibiting decarburization reactions, controlling temperature uniformity, and providing safety protection; detailed explanations are as follows:

[0056] Nitrogen, as an inert gas, can reduce the oxygen content in the furnace to ≤0.5%, blocking direct contact between the metal surface and oxygen and preventing the formation of oxide scale (Fe3O4, Fe2O3, etc.). Oxide scale will lead to an increase in surface roughness (Ra value increases by 0.2~0.5μm), affecting the assembly accuracy of the bearing housing.

[0057] Maintaining surface smoothness and keeping the bearing housing surface in an oxygen-free environment preserves its original metallic color, reducing the difficulty of subsequent processing (such as grinding and plating).

[0058] Carbon element protection: In an oxygen-containing environment, high temperature causes carbon elements in steel to combine with oxygen to generate CO or CO2 (decarburization reaction), resulting in a decrease in surface carbon content; the decarburized layer depth can reach 0.05-0.1mm, leading to a decrease in surface hardness (HV decrease of 50-100) and a shortened fatigue life.

[0059] To maintain material properties, under nitrogen protection, the carbon content on the bearing housing surface remains stable, ensuring the integrity of the hardened layer and that wear resistance and tensile strength meet design requirements.

[0060] Nitrogen gas, a homogenizing medium, circulates within the furnace (flow rate 0.5–1.0 m / s) to promote uniform heat distribution, reduce local temperature differences (within ±5℃), and prevent uneven tempering caused by temperature gradients (such as local over-tempering or under-tempering).

[0061] Reduce thermal stress; a uniform temperature field can reduce residual stress inside the workpiece and prevent deformation after tempering (e.g., ellipticity deviation <0.01mm).

[0062] It suppresses the generation of harmful gases and prevents the decomposition of lubricating oil residues at high temperatures to produce corrosive gases such as CO and H2S, thus protecting the furnace and sensors;

[0063] For safety, nitrogen can replace flammable gases (such as hydrogen) inside the furnace, reducing the risk of explosion.

[0064] The following table compares the nitrogen-filled embodiments of this application with the traditional process:

[0065] Surface oxide layer 5~10μm <1μm Decarburization layer depth 0.08~0.12mm Not detected Hardness uniformity HV fluctuation ±50 HV fluctuation ±10 Furnace temperature uniformity ±15℃ ±5℃

[0066] Therefore, it can be seen that the introduction of nitrogen gas in this application is a key step in controlling material properties during the tempering process: by isolating oxygen, oxidation and decarburization are avoided, maintaining surface hardness and wear resistance; by circulating gas, uniform temperature is achieved, thermal stress is reduced, and dimensional stability is ensured; in the manufacturing of precision bearings, nitrogen protection can increase the life of the workpiece by 20% to 30%.

[0067] Example 3

[0068] In Embodiment 3 of this application, as Figure 2 As shown, a micro motor structure is also provided, which includes a housing, a stator assembly, a rotor shaft, a bearing housing, and an end cover. The inner wall of the housing is provided with an annular groove, the depth of which gradually changes circumferentially. The outer edge of the stator assembly is provided with a wedge-shaped protrusion that engages with the annular groove. The outer surface of the wedge-shaped protrusion is covered with a viscoelastic damping layer. The rotor shaft is press-fitted into the bearing housing, which is tapered and has a corrugated buffer pad at its bottom. The upper end of the housing is provided with an opening, and a shape memory alloy ring is embedded in the lower outer periphery of the end cover. The end cover is installed on the upper end of the housing and is used to close the opening. After the end cover is installed on the upper end of the housing, the end cover is heat-treated so that the shape memory alloy ring generates radial preload and abuts and locks against the inner wall of the housing. Specifically, multiple experiments have shown that the micro motor structure formed according to the micro motor assembly method described above has a 92% lower screw loosening rate and an axial displacement of less than 3μm under 2000Hz vibration, exhibiting extremely strong structural stability and being difficult to loosen.

[0069] The depth of the annular groove varies in a gradient of 0.05 mm / °. During assembly, the stator assembly needs to be rotated to a specific phase angle to be fully embedded. The gradient calculation formula for the annular groove is: Δh = 0.05 × θ (θ is the phase angle). For example, if the stator assembly is rotated to a phase angle θ = 30° (groove depth Δh = 1.5 mm) and embedded into the housing, a laser positioning sensor (industrial camera) can be used to calibrate the phase during the assembly of the stator assembly and the housing. The angle of the wedge-shaped protrusion (forming a self-locking angle with the inner wall of the annular groove) is 12°. The locking position between the wedge-shaped protrusion and the annular groove is: when the stator is rotated to θ = 30°, the protrusion is fully embedded in the deepest area of ​​the groove, generating an axial preload of 15N. A continuous axial component force (approximately 15N) is generated between the two, effectively counteracting the separation tendency caused by vibration. No additional locking parts are required, improving assembly efficiency by 40%.

[0070] In this embodiment, the viscoelastic damping layer is a silicone-graphene composite material with a thickness of 0.1-0.3 mm and a loss factor ≥0.5; furthermore, the silicone matrix is ​​doped with 15% sheet graphene (thickness 2-5 nm); forming a three-dimensional thermally conductive and energy-dissipating network, which can reduce the vibration acceleration of 2000 Hz by 18 dB in actual measurements, while improving the heat dissipation efficiency by 30%.

[0071] In this embodiment, the corrugated buffer pad is configured with gradient pores or a honeycomb structure.

[0072] In this embodiment, the viscoelastic damping layer includes a gradient-distributed carbon nanotube interlayer with a density of 5-15 mg / cm³. 3 The surface is equipped with a micro-nano pyramid array with a height of 50μm.

[0073] In this embodiment, the inner wall of the outer casing is further provided with a plurality of elastic buckles at equal intervals. The elastic buckles are arranged in a cantilever beam structure, and the ends of the elastic buckles are provided with hemispherical protrusions. The number of elastic buckles is an integer multiple of the number of stator poles. Preferably, there are 6 elastic buckles (the number of stator poles is 6), and the diameter of the hemispherical protrusions at the ends is 0.8mm, so that when the stator assembly is assembled with the outer casing, the interference fit between it and the inner wall of the outer casing is 0.05mm.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the present invention without departing from the scope of the present invention are within the scope of the present invention.

Claims

1. A micro motor structure, characterized in that: The device includes a housing, a stator assembly, a rotor shaft, a bearing housing, and an end cover. The inner wall of the housing has an annular groove with a gradually changing depth along the circumference. The outer edge of the stator assembly has a wedge-shaped protrusion that engages with the annular groove. The outer surface of the wedge-shaped protrusion is covered with a viscoelastic damping layer. The rotor shaft is press-fitted into the bearing housing, which is tapered and has a corrugated buffer pad at its bottom. The upper end of the housing has an opening. A shape memory alloy ring is embedded in the lower outer periphery of the end cover. The end cover is installed on the upper end of the housing and closes the opening. After the end cover is installed on the upper end of the housing, it is heat-treated to generate a radial preload on the shape memory alloy ring, which then abuts and locks against the inner wall of the housing. The depth of the annular groove varies in a gradient of 0.05 mm / °. The gradient calculation formula for the annular groove is: Δh = 0.05 × θ, where θ is the phase angle. When the stator assembly rotates to a phase angle of θ = 30°, the stator assembly is embedded into the outer shell with an annular groove gradient of Δh = 1.5 mm. The angle between the wedge-shaped protrusion and the inner wall of the annular groove is 12°. The locking position between the wedge-shaped protrusion and the annular groove is: when the stator rotates to θ = 30°, the wedge-shaped protrusion is embedded in the deepest area of ​​the annular groove to generate an axial preload of 15 N. The viscoelastic damping layer is a silicone-graphene composite material with a thickness of 0.1-0.3 mm and a loss factor ≥0.

5. The silicone matrix of the viscoelastic damping layer is doped with 15% sheet graphene with a thickness of 2-5 nm, forming a three-dimensional heat-conducting and energy-dissipating network. The inner wall of the outer shell is also provided with multiple elastic buckles at equal intervals. The elastic buckles are arranged in a cantilever beam structure, and the ends of the elastic buckles are provided with hemispherical protrusions.

2. The micro motor structure according to claim 1, characterized in that: The corrugated buffer pad is configured with gradient pores or a honeycomb structure.

3. The micro motor structure according to claim 1, characterized in that: The viscoelastic damping layer contains a gradient-distributed carbon nanotube intermediate layer with a density of 5-15 mg / cm³, and has a micro-nano pyramid array with a height of 50 μm on its surface.

4. The micro motor structure according to claim 1, characterized in that: The number of elastic clips is an integer multiple of the stator pole number.

5. A micro motor structure according to claim 4, characterized in that: There are 6 elastic buckles.

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