A micro motor assembly system

Abstract

The present application relates to the technical field of motor assembly, in particular to a micro motor assembly system, which comprises a man-machine interaction device, a feeding device, an assembly device, a transfer device, a liquid nitrogen cooling device, a shape memory alloy activation device and a temperature recovery monitoring system; the assembly device comprises a first assembly mechanism, a second assembly mechanism and a third assembly mechanism; the feeding device comprises a first feeding mechanism, a second feeding mechanism, a third feeding mechanism, a fourth feeding mechanism and a fifth feeding mechanism; the transfer device comprises a first transfer mechanism, a second transfer mechanism and a third transfer mechanism. The present application integrates the man-machine interaction device, the assembly device, the feeding device, the transfer device, the liquid nitrogen cooling device, the shape memory alloy activation device and the temperature recovery monitoring system, realizes the full-process automatic assembly of the micro motor assembly, reduces manual intervention, improves efficiency and consistency, and ensures that the produced micro motor is not easy to loosen and has strong structural stability.

Description

Technical Field

[0001] This invention relates to the field of motor assembly technology, and in particular to an assembly system for a micro motor. Background Technology

[0002] Traditional micro motors are prone to performance degradation or even failure under vibration due to issues such as loose screws and structural wear. Existing technologies often address these problems by using bolts for fixing or adding vibration-damping materials, but the effectiveness is limited, and assembly is complex and maintenance costs are high. Furthermore, existing micro motor assembly systems lack sufficient automation and coordination: traditional assembly systems rely on independent workstations (such as conveyor tracks and sensors working in conjunction with separate pressing and feeding mechanisms). Due to the design of multiple bolts for fixing and positioning, the coordinated scheduling of robotic arms is extremely difficult, resulting in high collision rates in the transfer path and low production efficiency. Therefore, there is an urgent need for an innovative micro motor assembly system to achieve more secure and less prone-to-loose assembly of micro motors. Summary of the Invention

[0003] This invention addresses the problems of existing technologies by providing a micro motor assembly system that integrates a human-machine interface device, an assembly device, a feeding device, a transfer device, a liquid nitrogen cooling device, a shape memory alloy activation device, and a temperature recovery monitoring system. This system achieves fully automated assembly of micro motor components, reduces manual intervention, improves efficiency and consistency, and ensures that the micro motors produced by this assembly system maintain structural stability under long-term vibration, are not easily loosened, and have strong structural stability.

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

[0005] This invention provides a micro motor assembly system, which includes a human-machine interface device, a feeding device, an assembly device, a transfer device, a liquid nitrogen cooling device, a shape memory alloy activation device, and a temperature recovery monitoring system; the feeding device, assembly device, transfer device, liquid nitrogen cooling device, shape memory alloy activation device, and temperature recovery monitoring system are respectively signal-connected to the human-machine interface device.

[0006] The assembly device includes a first assembly mechanism for assembling the stator assembly and the housing, a second assembly mechanism for press-fitting the rotor shaft into the bearing housing, a third assembly mechanism for assembling the bearing housing into the stator assembly, and a fourth assembly mechanism for installing the end cover into the upper opening of the housing.

[0007] The feeding device includes a first feeding mechanism for feeding the stator assembly, a second feeding mechanism for feeding the housing, a third feeding mechanism for feeding the rotor shaft, a fourth feeding mechanism for feeding the bearing seat, and a fifth feeding mechanism for feeding the end cover.

[0008] The transfer device includes a first transfer mechanism for transferring the bearing housing in the liquid nitrogen cooling device to the second assembly mechanism, a second transfer mechanism for transferring the bearing housing in the second assembly mechanism to the third assembly mechanism, a third transfer mechanism for transferring the housing after assembling the stator assembly to the third assembly mechanism, a fourth transfer mechanism for transferring the housing after assembling the bearing housing to the temperature recovery monitoring system, a fifth transfer mechanism for transferring the housing in the temperature recovery monitoring system to the fourth assembly mechanism, and a sixth transfer mechanism for transferring the housing after assembling the end cap to the shape memory alloy activation device.

[0009] The liquid nitrogen cooling device is used to cool the bearing housing with liquid nitrogen; the shape memory alloy activation device is used to heat the shape memory alloy ring to generate radial preload; the temperature recovery monitoring system is used to monitor the interference fit and axial displacement of the rotor shaft and bearing housing after recovery at room temperature.

[0010] The first assembly mechanism includes a first positioning seat, a first six-axis robot, and a second six-axis robot. The first six-axis robot is used to pick up the outer shell and place it on the first positioning seat. The first positioning seat is used to support and position the outer shell. The second six-axis robot is used to pick up the stator assembly and assemble it inside the outer shell.

[0011] The liquid nitrogen cooling device includes a third six-axis manipulator, a cooling chamber, a lifting mechanism installed in the cooling chamber, and a rotating mechanism installed on the lifting mechanism. The cooling chamber is filled with liquid nitrogen. The rotating mechanism is used to carry the bearing seat and drive the bearing seat to rotate. The lifting mechanism is used to drive the rotating mechanism to move up and down. The rotating mechanism includes a rotating drive component and a rotating table connected to the rotating drive component. A limit groove is provided on the rotating table. The third six-axis manipulator is used to transfer the bearing seat from the fourth loading mechanism to the cooling chamber.

[0012] The bearing housing is tapered. When cooling is required, 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 as follows: when cooling the tapered area of ​​the tapered bearing housing, the cooling rate is 50℃ / min.

[0013] When cooling the bottom area of ​​the tapered bearing housing, the cooling rate is 30℃ / min; the cooling time t during the cooling of 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).

[0014] The cooling chamber has an annular nozzle on its inner wall, and the inner sidewall of the annular nozzle has multiple spray holes at equal intervals. The rotating mechanism is located in the middle of the cooling chamber. The annular nozzle uses two-phase nitrogen gas (gas and liquid) to be injected into the cooling chamber through the spray holes of the annular nozzle, and the injection pressure is controlled to be 0.15 MPa.

[0015] The first transfer mechanism includes a fourth six-axis robot, which is used to pick up the bearing housing in the cooling cavity and transfer it to the second assembly mechanism.

[0016] The second assembly mechanism includes a second positioning seat and a fifth and sixth axis robot arm. The fifth and sixth axis robot arm is used to pick up the rotor shaft from the third feeding mechanism and press it into the bearing housing. The second positioning seat is used to support and position the bearing housing.

[0017] The second transfer mechanism includes a sixth six-axis robot arm, the third assembly mechanism includes a third positioning seat and a seventh six-axis robot arm, and the third transfer mechanism includes an eighth six-axis robot arm;

[0018] The third positioning seat is provided with a first positioning groove and a second positioning groove. The first positioning groove is used to position the bearing seat, and the second positioning groove is used to position the outer shell. The sixth six-axis robot is used to transfer the bearing seat on the second positioning seat into the first positioning groove. The eighth six-axis robot is used to transfer the outer shell after the stator assembly is assembled in the first assembly mechanism to the second positioning groove. The seventh six-axis robot is used to pick up the bearing seat on the first positioning groove and press it into the stator assembly of the outer shell on the second positioning groove.

[0019] The fourth transfer mechanism includes a 96-axis robot arm, which is used to transfer the outer shell after the bearing housing is press-fitted into the temperature recovery monitoring system.

[0020] The fourth assembly mechanism includes a fourth positioning seat and a sixteenth-axis robot arm, and the fifth transfer mechanism includes an eleventh-sixth-axis robot arm. The eleventh-sixth-axis robot arm is used to transfer the outer shell of the temperature recovery monitoring system to the fourth positioning seat. The fourth positioning seat is used to support and position the outer shell. The sixteenth-axis robot arm is used to transfer and assemble the end cap fed by the fifth feeding mechanism to the upper opening of the outer shell of the fourth positioning seat.

[0021] The sixth transfer mechanism includes a twelfth-sixth-axis robot arm, which is used to transfer the assembled end cap shell into the shape memory alloy activation device.

[0022] The micro motor assembly system also includes a discharge device, which includes a 13th-6th axis robot arm. The 13th-6th axis robot arm is used to discharge the micro motor assembled in the shape memory alloy activation device.

[0023] The beneficial effects of this invention are:

[0024] This invention achieves fully automated assembly of micro motor components by integrating a human-machine interface device, assembly device, feeding device, transfer device, liquid nitrogen cooling device, shape memory alloy activation device, and temperature recovery monitoring system. This reduces manual intervention and improves efficiency and consistency. Furthermore, the liquid nitrogen cooling device cools the bearing housing before pressing the rotor shaft, allowing it to return to room temperature and form an interference fit, maintaining the connection stability between the bearing housing and the rotor shaft. The temperature recovery monitoring system monitors the interference fit and axial displacement between the rotor shaft and the bearing housing in real time, feeding this information back to the human-machine interface device for technician inspection. Additionally, the heat-induced deformation compensation of the shape memory alloy ring during end cap assembly ensures that the micro motors produced by this assembly system maintain structural stability under long-term vibration, preventing loosening and demonstrating strong structural stability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a micro motor assembly system according to the present invention.

[0026] Figure 2 This is a schematic diagram of the liquid nitrogen cooling device of the present invention.

[0027] Figure 3 This is a schematic diagram of the third assembly mechanism of the present invention.

[0028] Figure 4 This is an exploded view of a micro motor structure according to the present invention.

[0029] exist Figures 1 to 4 The reference numerals in the figures include:

[0030] 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;

[0031] 20. Liquid nitrogen cooling device; 21. Third six-axis manipulator; 22. Lifting mechanism; 23. Rotary drive component; 24. Rotary table; 25. Limiting groove; 26. Cooling chamber; 27. Annular nozzle; 28. Spray hole; 29. ​​Third positioning seat; 30. Seventh six-axis manipulator; 31. First positioning groove; 32. Second positioning groove. Detailed Implementation

[0032] 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.

[0033] like Figures 1 to 3 The micro motor assembly system shown includes a human-machine interface device, a feeding device, an assembly device, a transfer device, a liquid nitrogen cooling device 20, a shape memory alloy activation device, and a temperature recovery monitoring system; the feeding device, assembly device, transfer device, liquid nitrogen cooling device 20, shape memory alloy activation device, and temperature recovery monitoring system are respectively signal-connected to the human-machine interface device.

[0034] The assembly device includes a first assembly mechanism for assembling the stator assembly 2 and the housing 1, a second assembly mechanism for pressing the rotor shaft 3 into the bearing housing 4, a third assembly mechanism for assembling the bearing housing 4 into the stator assembly 2, and a fourth assembly mechanism for installing the end cover 5 into the upper opening of the housing 1.

[0035] The feeding device includes a first feeding mechanism for feeding the stator assembly 2, a second feeding mechanism for feeding the housing 1, a third feeding mechanism for feeding the rotor shaft 3, a fourth feeding mechanism for feeding the bearing seat 4, and a fifth feeding mechanism for feeding the end cover 5.

[0036] The transfer device includes a first transfer mechanism for transferring the bearing housing 4 in the liquid nitrogen cooling device 20 to the second assembly mechanism, a second transfer mechanism for transferring the bearing housing 4 in the second assembly mechanism to the third assembly mechanism, a third transfer mechanism for transferring the outer shell 1 after assembling the stator assembly 2 to the third assembly mechanism, a fourth transfer mechanism for transferring the outer shell 1 after assembling the bearing housing 4 to the temperature recovery monitoring system, a fifth transfer mechanism for transferring the outer shell 1 in the temperature recovery monitoring system to the fourth assembly mechanism, and a sixth transfer mechanism for transferring the outer shell 1 after assembling the end cap 5 to the shape memory alloy activation device.

[0037] The liquid nitrogen cooling device 20 is used to cool the bearing housing 4 with liquid nitrogen; the shape memory alloy activation device is used to heat the shape memory alloy ring 9 to generate radial preload; the temperature recovery monitoring system is used to monitor the interference fit and axial displacement of the rotor shaft 3 and the bearing housing 4 after recovery at room temperature.

[0038] Specifically, this invention achieves fully automated assembly of micro motor components by integrating a human-machine interface device, an assembly device, a feeding device, a transfer device, a liquid nitrogen cooling device 20, a shape memory alloy activation device, and a temperature recovery monitoring system. This reduces manual intervention and improves efficiency and consistency. Furthermore, the liquid nitrogen cooling device 20 cools the bearing housing 4 with liquid nitrogen before pressing the rotor shaft 3, and after returning to room temperature, an interference fit is formed, maintaining the connection stability between the bearing housing 4 and the rotor shaft 3. The temperature recovery monitoring system monitors the interference and axial displacement between the rotor shaft 3 and the bearing housing 4 in real time and feeds it back to the human-machine interface device for technical personnel to inspect. In addition, the vibration energy dissipation compensated by the thermal deformation of the shape memory alloy ring 9 during the assembly of the end cap 5 ensures that the micro motor produced by the assembly system of this invention can maintain structural stability under long-term vibration, is not easy to loosen, and has strong structural stability.

[0039] In this embodiment of the application, the first assembly mechanism includes a first positioning seat, a first six-axis robot, and a second six-axis robot. The first six-axis robot is used to pick up the outer shell 1 and place it on the first positioning seat. The first positioning seat is used to support and position the outer shell 1. The second six-axis robot is used to pick up the stator assembly 2 and assemble it inside the outer shell 1.

[0040] In this embodiment, the liquid nitrogen cooling device 20 includes a third six-axis manipulator 21, a cooling chamber 26, a lifting mechanism 22 installed in the cooling chamber 26, and a rotating mechanism installed on the lifting mechanism 22; the cooling chamber 26 is filled with liquid nitrogen; the rotating mechanism is used to carry the bearing seat 4 and drive the bearing seat 4 to rotate; the lifting mechanism 22 is used to drive the rotating mechanism to move up and down; the rotating mechanism includes a rotating drive component 23 and a rotating table 24 connected to the rotating drive component 23; the rotating table 24 is provided with a limiting groove 25; the third six-axis manipulator 21 is used to transfer the bearing seat 4 from the fourth feeding mechanism to the cooling chamber 26. The inner wall of the cooling chamber 26 is provided with an annular nozzle 27, and the inner side wall of the annular nozzle 27 is provided with a plurality of spray holes 28 at equal intervals; the rotating mechanism is located in the middle of the cooling chamber 26, and the annular nozzle 27 uses gas-liquid two-phase nitrogen gas to be injected into the cooling chamber 26 through the spray holes 28 of the annular nozzle 27, and the injection pressure is controlled to be 0.15MPa.

[0041] In this embodiment, the bearing housing is tapered. When cooling is required, 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 as follows: when cooling the tapered surface area of ​​the tapered bearing housing, the cooling rate is 50℃ / min; this setting is beneficial for enhancing material shrinkage efficiency. When cooling the bottom area of ​​the tapered bearing housing, the cooling rate is 30℃ / min; this setting is beneficial for reducing 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. The cooling time t during bearing housing cooling 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).

[0042] In this process, 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 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. Uniform rotation ensures even contact between the liquid nitrogen and the bearing housing, guaranteeing a temperature difference of <5°C between the various surfaces of the bearing housing. Preferably, an annular nozzle is provided in the cooling chamber of the liquid nitrogen cooling system, and the inner wall of the annular nozzle has multiple equally spaced nozzle holes. Furthermore, in the liquid nitrogen cooling system, two-phase nitrogen gas is injected into the cooling chamber through the nozzle holes of the annular nozzle, and the injection pressure is controlled at 0.15 MPa to reduce the risk of cold impact cracking.

[0043] In the process of pressing the rotor shaft into the bearing housing, a staged pressing operation can be adopted. After the bearing housing has cooled, it is pressed into the rotor shaft at a staged speed of 0.5 mm / s, specifically in three stages:

[0044] 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.

[0045] 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.

[0046] 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.

[0047] This embodiment of the application, through the aforementioned graded pressing operation, ensures reliable and stable pressing of the rotor shaft and bearing housing, preventing sudden changes in cold shrinkage and ensuring the interference fit between the rotor shaft and bearing housing. It also eliminates residual stress, resulting in a better pressing effect. To detect whether there is an interference fit between the rotor shaft and bearing housing, 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.

[0048] In this embodiment, the bearing housing is cooled with liquid nitrogen followed by cryogenic tempering; the process steps are as follows:

[0049] Temperature rise control:

[0050] 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.

[0051] Tempering parameter settings:

[0052] 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℃.

[0053] 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).

[0054] Tempering procedure:

[0055] Preheat the equipment and tempering furnace to the target temperature (±5℃) to avoid uneven heating of the workpiece;

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Performance testing includes checking surface hardness (HV 700~750) and retained austenite content (≤5%) to ensure microstructure stability.

[0060] After the above tempering process, and through multiple experiments, the following technical comparison table is obtained:

[0061]

[0062]

[0063] 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%.

[0064] 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:

[0065] 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.

[0066] 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).

[0067] 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.

[0068] 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.

[0069] 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).

[0070] 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).

[0071] 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;

[0072] For safety, nitrogen can replace flammable gases (such as hydrogen) inside the furnace, reducing the risk of explosion.

[0073] The following table compares the nitrogen-filled embodiments of this application with the traditional process:

[0074] parameter Nitrogen-free protection (air environment) Nitrogen protection process (this application) 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℃

[0075] 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%.

[0076] In this embodiment of the application, the first transfer mechanism includes a fourth six-axis robot, which is used to pick up the bearing seat in the cooling cavity and transfer it to the second assembly mechanism.

[0077] In this embodiment of the application, the second assembly mechanism includes a second positioning seat and a fifth and sixth axis manipulator. The fifth and sixth axis manipulator is used to pick up the rotor shaft from the third feeding mechanism and press it into the bearing seat. The second positioning seat is used to support and position the bearing seat.

[0078] In this embodiment, the second transfer mechanism includes a sixth six-axis robot, the third assembly mechanism includes a third positioning seat and a seventh six-axis robot, and the third transfer mechanism includes an eighth six-axis robot. The third positioning seat is provided with a first positioning groove and a second positioning groove. The first positioning groove is used to position the bearing housing, and the second positioning groove is used to position the outer casing. The sixth six-axis robot is used to transfer the bearing housing on the second positioning seat into the first positioning groove. The eighth six-axis robot is used to transfer the outer casing after the stator assembly is assembled in the first assembly mechanism to the second positioning groove. The seventh six-axis robot is used to pick up the bearing housing from the first positioning groove and press it into the stator assembly of the outer casing in the second positioning groove. The fourth transfer mechanism includes a ninth six-axis robot, which is used to transfer the outer casing after pressing the bearing housing into the temperature recovery monitoring system.

[0079] In this embodiment of the application, the fourth assembly mechanism includes a fourth positioning seat and a sixteenth-axis robot arm, and the fifth transfer mechanism includes an eleventh-sixth-axis robot arm. The eleventh-sixth-axis robot arm is used to transfer the outer shell inside the temperature recovery monitoring system to the fourth positioning seat. The fourth positioning seat is used to support and position the outer shell. The sixteenth-axis robot arm is used to transfer and assemble the end cap fed by the fifth feeding mechanism to the upper opening of the outer shell of the fourth positioning seat.

[0080] In this embodiment, the sixth transfer mechanism includes a twelfth-sixth-axis robot arm, which is used to transfer the outer shell after the end cap is assembled to the shape memory alloy activation device; the micro motor assembly system also includes a discharge device, which includes a thirteenth-sixth-axis robot arm, which is used to discharge the micro motor assembled in the shape memory alloy activation device.

[0081] Specifically, during the installation of the end cap, axial compression is applied to the shape memory alloy ring, and radial expansion is triggered by heating to 80-100°C. Specifically, during the installation of the end cap, axial compression is applied to the shape memory alloy ring, and upon cooling to 20°C, the shape memory alloy ring radially contracts 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°C. Dual-modal compensation: radial contraction of 0.12% upon cooling to -20°C achieves temperature-adaptive preload; preload fluctuation <5% (-40~120°C 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 preload fluctuation <5%.

[0082] In this embodiment, the six-axis robot is existing technology and will not be described in detail here. Its functions and actions can be programmed by technicians according to the operational requirements. In addition, the human-machine interaction device, feeding device, assembly device, transfer device, liquid nitrogen cooling device, shape memory alloy activation device, and temperature recovery monitoring system described in this embodiment are all commonly used devices in mechanical equipment or motor production. This embodiment does not focus on independent equipment innovation, but rather on integrating a new production process for micro motors and automating its production.

[0083] like Figure 4As shown, the micro motor structure produced by the system of this application embodiment includes a housing 1, a stator assembly 2, a rotor shaft 3, a bearing seat 4, and an end cover 5. The inner wall of the housing 1 is provided with an annular groove 6, the depth of which gradually changes circumferentially. The outer edge of the stator assembly 2 is provided with a wedge-shaped protrusion 7 that engages with the annular groove 6. The outer surface of the wedge-shaped protrusion 7 is covered with a viscoelastic damping layer. The rotor shaft 3 is press-fitted into the bearing seat 4. The bearing seat 4 is tapered, and a corrugated buffer pad 8 is provided at the bottom of the bearing seat 4. The upper end of the housing 1 is provided with an opening. A shape memory alloy ring 9 is embedded in the lower outer periphery of the end cover 5. The end cover 5 is installed on the upper end of the housing 1 and is used to close the opening. After the end cover 5 is installed on the upper end of the housing 1, the end cover 5 is heat-treated so that the shape memory alloy ring 9 generates radial preload and abuts and locks against the inner wall of the housing 1. 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.

[0084] The depth of the annular groove 6 varies in a gradient of 0.05 mm / °. During assembly, the stator assembly 2 needs to be rotated to a specific phase angle to be fully embedded. The gradient calculation formula for the annular groove 6 is: Δh = 0.05 × θ (θ is the phase angle). For example, if the stator assembly 2 is rotated to a phase angle θ = 30° (groove depth Δh = 1.5 mm) and embedded in the housing 1, a laser positioning sensor (industrial camera) can be used to calibrate the phase when assembling the stator assembly 2 and the housing 1. The angle of the wedge-shaped protrusion 7 (forming a self-locking angle with the inner wall of the annular groove 6) is 12°. The locking position between the wedge-shaped protrusion 7 and the annular groove 6 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 15 N. A continuous axial component force (approximately 15 N) is generated between the two, effectively counteracting the separation tendency caused by vibration. No additional locking parts are required, and the assembly efficiency is improved by 40%.

[0085] 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%.

[0086] In this embodiment, the corrugated buffer pad is configured with gradient pores or a honeycomb structure.

[0087] 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.

[0088] In this embodiment, the inner wall of the outer shell 1 is also provided with a plurality of elastic buckles 10 at equal intervals. The elastic buckles 10 are arranged in a cantilever beam structure, and the end of the elastic buckle 10 is provided with a hemispherical protrusion 11. The number of elastic buckles 10 is an integer multiple of the number of stator poles. Preferably, there are 6 elastic buckles 10 (the number of stator poles is 6), and the diameter of the hemispherical protrusion 11 at the end is 0.8mm, so that when the stator assembly 2 is assembled with the outer shell 1, the interference between it and the inner wall of the outer shell 1 is 0.05mm.

[0089] The viscoelastic damping layer of this invention uses a silicone-graphene composite material to form a three-dimensional heat-conducting and energy-dissipating network, effectively reducing vibration acceleration while improving heat dissipation efficiency. Liquid nitrogen cooling and staged press fitting: The bearing housing 4 is cooled to -196℃ by liquid nitrogen and then press-fitted with the rotor shaft 3 in stages to form an interference fit; the non-uniform gradient cooling and staged press fitting process reduces stress concentration, improves assembly accuracy and the structural strength of the bearing housing 4. Shape memory alloy self-compensation: The shape memory alloy ring 9 expands radially after heating and contracts upon cooling, achieving temperature-adaptive pre-tightening, effectively compensating for wear and ensuring long-term stable operation. Temperature recovery monitoring and feedback: The temperature recovery monitoring system monitors the interference fit and axial displacement of the rotor shaft 3 and bearing housing 4 in real time, ensuring the reliability of the assembly effect and reducing maintenance costs.

[0090] 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. An assembly system for a micromotor, characterized by: The device comprises a human-computer interaction device, a feeding device, an assembling device, a transferring device, a liquid nitrogen cooling device, a shape memory alloy activating device, and a temperature recovery monitoring system; the feeding device, the assembling device, the transferring device, the liquid nitrogen cooling device, the shape memory alloy activating device, and the temperature recovery monitoring system are signal connected with the human-computer interaction device respectively; The assembling device comprises a first assembling mechanism for assembling the stator assembly with the shell, a second assembling mechanism for pressing the rotor shaft into the bearing seat, a third assembling mechanism for assembling the bearing seat into the stator assembly, and a fourth assembling mechanism for mounting the end cover to the upper opening of the shell; The feeding device comprises a first feeding mechanism for feeding the stator assembly, a second feeding mechanism for feeding the shell, a third feeding mechanism for feeding the rotor shaft, a fourth feeding mechanism for feeding the bearing seat, and a fifth feeding mechanism for feeding the end cover; The transferring device comprises a first transferring mechanism for transferring the bearing seat in the liquid nitrogen cooling device into the second assembling mechanism, a second transferring mechanism for transferring the bearing seat in the second assembling mechanism into the third assembling mechanism, a third transferring mechanism for transferring the shell after assembling the stator assembly into the third assembling mechanism, a fourth transferring mechanism for transferring the shell after assembling the bearing seat into the temperature recovery monitoring system, a fifth transferring mechanism for transferring the shell in the temperature recovery monitoring system into the fourth assembling mechanism, and a sixth transferring mechanism for transferring the shell after assembling the end cover into the shape memory alloy activating device; The liquid nitrogen cooling device is used for cooling the bearing seat with liquid nitrogen; the shape memory alloy activating device is used for heating the shape memory alloy ring to generate radial pre-tightening force; and the temperature recovery monitoring system is used for monitoring the interference fit and axial displacement of the rotor shaft and the bearing seat after temperature recovery.

2. The micro motor assembly system according to claim 1, wherein: The first assembling mechanism comprises a first positioning seat, a first six-axis manipulator, and a second six-axis manipulator; the first six-axis manipulator is used for taking the shell and placing it on the first positioning seat; the first positioning seat is used for bearing and positioning the shell; and the second six-axis manipulator is used for taking the stator assembly and assembling it in the shell.

3. The micro-motor assembly system of claim 1, wherein: The liquid nitrogen cooling device comprises a third six-axis manipulator, a cooling cavity, a lifting mechanism arranged in the cooling cavity, and a rotating mechanism arranged on the lifting mechanism; the cooling cavity is filled with liquid nitrogen; the rotating mechanism is used for bearing and rotating the bearing seat; the lifting mechanism is used for driving the rotating mechanism to move up and down; the rotating mechanism comprises a rotating drive member and a rotating table connected with the rotating drive member; the rotating table is provided with a limiting groove; and the third six-axis manipulator is used for transferring the bearing seat from the fourth feeding mechanism into the cooling cavity.

4. The micro-motor assembly system according to claim 3, wherein: The bearing seat is conical; when the bearing seat needs to be cooled, the conical bearing seat is completely immersed in liquid nitrogen, and the cooling rate is controlled by a non-uniform gradient; the method for controlling the non-uniform gradient is that when the conical surface area of the conical bearing seat is cooled, the cooling rate is 50℃ / min; when the bottom area of the conical bearing seat is cooled, the cooling rate is 30℃ / min; wherein when the bearing seat is cooled, the cooling time t is calculated according to the workpiece mass, formula: t=0.05m 1.2 wherein t is the cooling time (min), and m is the workpiece mass (kg).

5. The micro-motor assembly system of claim 3, wherein: The inner wall of the cooling cavity is annularly provided with an annular spray pipe; the inner side wall of the annular spray pipe is annularly provided with a plurality of spray holes at equal intervals; the rotating mechanism is located in the middle of the cooling cavity; and the annular spray pipe sprays nitrogen gas in gas-liquid phase to the cooling cavity through the spray holes of the annular spray pipe, and the control injection pressure is 0.15 MPa.

6. The micro-motor assembly system of claim 3, wherein: The first transfer mechanism comprises a fourth six-axis robot, which is used to pick up the bearing seat in the cooling cavity and transfer it to the second assembly mechanism.

7. The micro-motor assembly system of claim 1, wherein: The second assembly mechanism comprises a second positioning seat and a fifth six-axis robot, which is used to pick up the rotor shaft from the third feeding mechanism and press-fit it into the bearing seat, and the second positioning seat is used to carry and position the bearing seat.

8. The micro-motor assembly system according to claim 7, wherein: The second transfer mechanism comprises a sixth six-axis robot, the third assembly mechanism comprises a third positioning seat and a seventh six-axis robot, and the third transfer mechanism comprises an eighth six-axis robot; the third positioning seat is provided with a first positioning groove and a second positioning groove, the first positioning groove is used to position the bearing seat, the second positioning groove is used to position the shell, the sixth six-axis robot is used to transfer the bearing seat on the second positioning seat into the first positioning groove, the eighth six-axis robot is used to transfer the shell after assembling the stator assembly in the first assembly mechanism to the second positioning groove, and the seventh six-axis robot is used to pick up the bearing seat on the first positioning groove and press-fit it into the stator assembly of the shell on the second positioning groove. The fourth transfer mechanism comprises a ninth six-axis robot, which is used to transfer the shell after press-fitting the bearing seat to the temperature recovery monitoring system.

9. The micro-motor assembly system of claim 1, wherein: The fourth assembly mechanism comprises a fourth positioning seat and a sixteenth six-axis robot, the fifth transfer mechanism comprises an eleventh six-axis robot, which is used to transfer the shell in the temperature recovery monitoring system to the fourth positioning seat, the fourth positioning seat is used to carry and position the shell, and the sixteenth six-axis robot is used to transfer and assemble the end cover fed by the fifth feeding mechanism to the shell on the fourth positioning seat.

10. The micro-motor assembly system of claim 9, wherein: The sixth transfer mechanism comprises a twelfth six-axis robot, which is used to transfer the shell after assembling the end cover to the shape memory alloy activation device. The micro motor assembly system further comprises a discharging device, and the discharging device comprises a thirteenth six-axis robot, which is used to discharge the micro motor assembled in the shape memory alloy activation device. The micro motor assembly system further comprises a discharging device, and the discharging device comprises a thirteenth six-axis robot, which is used to discharge the micro motor assembled in the shape memory alloy activation device.

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