Micro-textured nanofluid electrically-driven gear lubrication and heat dissipation system and method

Abstract

The present application relates to a kind of micro-texture nanofluid electric drive gear lubrication heat dissipation system and method, belong to electric drive gear transmission lubrication heat dissipation technical field, including mutually meshing transmission gear pair, oil supply unit and oil storage unit, the oil supply unit is used to supply lubricating medium to the meshing area of gear pair, the oil storage unit is used to store lubricating medium, the meshing area of the tooth surface of each gear in the gear pair is equipped with micro-texture array, the micro-texture array of the tooth surface meshing area of the present application is gradually arranged in sparse and dense, realize dynamic oil storage using the microcavity structure of circular micro-pit, in non-engagement stage, micro-pit stores nanofluid composite lubricating medium;In meshing contact stage, the micro-pit of contact area is released by tooth surface extrusion effect The lubricating medium stored in interior, continuously supplement oil liquid to the periphery of contact area, fill the area of oil film shear rupture, maintain the continuity and carrying capacity of oil film.

Description

Technical Field

[0001] This invention belongs to the field of electric drive gear transmission lubrication and heat dissipation technology, specifically relating to a microtextured nanofluid electric drive gear lubrication and heat dissipation system and method. Background Technology

[0002] As new energy vehicles rapidly develop towards higher power density and higher speed, the operating speed of gear transmission devices in electric drive systems generally reaches over 12,000 r / min, with some high-speed electric drives exceeding 16,000 r / min. At the same time, the torque carried continues to increase, and the gear meshing area faces extremely high contact stress and frictional heat load.

[0003] Traditional electric drive gears mostly use splash lubrication or constant flow oil injection lubrication, relying on base gear oil to achieve friction reduction and heat dissipation. However, this has significant limitations under high-speed and high-load conditions: First, the instantaneous contact stress and sliding-rolling ratio in the gear meshing area are high, and the oil film is prone to shearing and rupture during continuous meshing, leading to direct metal-to-metal contact on the gear surfaces. This exacerbates adhesive wear and abrasive wear, and long-term operation can easily induce pitting, galling, and other failures, significantly shortening the service life of the gears. Second, the base gear oil has a low thermal conductivity, making it difficult to quickly dissipate the frictional heat generated instantaneously in the meshing area. Long-term high-temperature operation will cause the lubricating oil to oxidize and deteriorate, and its viscosity to decrease, further damaging the oil film's load-bearing capacity and forming a vicious cycle of "high temperature - lubrication failure - even higher temperature". Summary of the Invention

[0004] The purpose of this invention is to provide a microtextured nanofluidic electric drive gear lubrication and heat dissipation system and method to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a microtextured nanofluidic electric drive gear lubrication and heat dissipation system, comprising a gear pair meshing and transmitting, an oil supply unit, and an oil storage unit. The oil supply unit is used to supply lubricating medium to the meshing area of ​​the gear pair, and the oil storage unit is used to store the lubricating medium. The meshing area of ​​the tooth surface of each gear in the gear pair is provided with a microtextured array. The microtextured array is composed of several independent microstructure units arranged in a regular manner, which is used to store the lubricating medium and dynamically replenish the oil film in the tooth surface contact area during gear meshing. The lubricating medium stored in the oil storage unit is a nanofluid composite lubricating medium, which is prepared by dispersing and stabilizing base gear oil and high thermal conductivity nanoparticles. The output end of the oil supply unit is correspondingly set on the meshing side of the gear pair and is used to spray the nanofluid composite lubricating medium onto the meshing tooth surface. The system also includes an adaptive control unit, the input end of which is connected to the gear condition detection module, and the output end is connected to the oil supply unit.

[0006] In a preferred embodiment, the microstructure unit of the microtexture array is a circular micro-dimple, with a diameter of 20~200μm and a depth of 5~50μm for each micro-dimple, and the area occupied by the microtexture in the meshing area of ​​the tooth surface is 5%~30%; the microtexture array is arranged with a gradual change in density along the pitch line of the tooth surface, and the microtexture density on the meshing side is greater than that on the disengaging side.

[0007] In a preferred embodiment, the high thermal conductivity nanoparticles are one or more of graphene oxide, nano-alumina, and nanodiamond, the particle size of the high thermal conductivity nanoparticles is 10~100nm, and the mass fraction of the high thermal conductivity nanoparticles in the base gear oil is 0.1%~5%.

[0008] In a preferred embodiment, the oil supply unit includes a variable frequency oil pump, a flow regulating valve, and at least one set of injection nozzles. The injection nozzles are positioned directly opposite the meshing side of the gear pair. Both the variable frequency oil pump and the flow regulating valve receive control signals from an adaptive control unit.

[0009] In a preferred embodiment, the gear condition detection module includes a speed sensor, a torque sensor, an oil temperature sensor, and a tooth surface temperature sensor, which are used to collect the real-time gear speed, load torque, lubricating oil temperature, and tooth surface working temperature and transmit them to the adaptive control unit.

[0010] In a preferred embodiment, the system further includes a circulating cooling filter unit. The input end of the circulating cooling filter unit is connected to the oil return port of the gearbox, and the output end is connected to the oil storage unit. It is used to filter and remove impurities from the returned nanofluid composite lubricating medium and cool it down before sending it back to the oil storage unit for recycling.

[0011] This invention also discloses a method for lubrication and heat dissipation of microtextured nanofluidic electric drive gears, comprising the following steps: S1 Preparation of nanofluid composite lubricating medium: Select high thermal conductivity nanoparticles and base gear oil. After surface modification of the high thermal conductivity nanoparticles, add them to the base gear oil and disperse them by ultrasonication to obtain a stable suspended nanofluid composite lubricating medium. S2. Tooth surface micro-texture processing: Using laser micro-machining technology, a micro-texture array with a preset arrangement is formed in the meshing area of ​​the tooth surface of the electric drive gear, so that the tooth surface has the ability to dynamically store oil and replenish oil film during the meshing process. S3. Constructing a lubrication and heat dissipation circuit: Assemble a lubrication and heat dissipation circuit including an oil storage unit, an oil supply unit, and a working condition detection module, and inject the prepared nanofluid composite lubricating medium into the oil storage unit. S4. Real-time acquisition of operating parameters: During gear operation, the operating parameters such as gear speed, load torque, lubricating oil temperature and tooth surface temperature are collected in real time through the operating condition detection module and transmitted to the control terminal. S5. Adaptive Lubrication and Heat Dissipation Control: Based on the received real-time operating parameters, the control unit calculates the target oil supply parameters through an adaptive control algorithm, outputs a control signal to adjust the oil supply flow and injection pressure of the oil supply unit, and precisely supplies nanofluid composite lubricating medium to the gear meshing area. Combined with the dynamic oil storage and film replenishment effect of the tooth surface microtexture and the high thermal conductivity of nanofluid, friction reduction and enhanced heat dissipation under different operating conditions are achieved.

[0012] In a preferred embodiment, the formula for calculating the target oil supply flow rate in step S5 is: In the formula: The target oil supply flow rate is expressed in L / min. This represents the real-time rotational speed of the gear, in r / min. This represents the real-time load torque of the gear, in N·m. This is the real-time tooth surface temperature, in °C. This is the preset reference operating temperature, in °C. , , The weighting coefficients are, in order, speed weighting coefficient, load weighting coefficient, and temperature weighting coefficient, all of which are predetermined through bench calibration tests.

[0013] In a preferred embodiment, in step S2, the microtexture array is arranged with a gradual change in density along the tooth height direction, with the microtexture density gradually increasing from the tooth root to the pitch line and gradually decreasing from the pitch line to the tooth tip.

[0014] In a preferred embodiment, the ultrasonic dispersion process takes 30 to 120 minutes and the processing temperature is controlled at 20 to 50°C.

[0015] In a preferred embodiment, in step S5, the basic target oil supply flow rate is calculated using a formula. Q Subsequently, a graded flow correction is performed based on the real-time tooth surface temperature to obtain the final oil supply flow rate. Q The correction rule satisfies the following formula: In the formula: The preset over-temperature warning threshold is set to 100℃~110℃. The preset low-temperature energy-saving threshold is set at 70℃~80℃. This is the overheating flow booster coefficient, with a value ranging from 15% to 25%. The low-temperature flow reduction coefficient is taken as 25%~35%, and satisfies the following conditions: .

[0016] In a preferred embodiment, in step S5, the adaptive control algorithm simultaneously calculates the target fuel supply flow rate and the target injection pressure, wherein the target injection pressure... The calculation formula is: In the formula: The target injection pressure is expressed in MPa. The reference injection pressure is 0.2~0.5 MPa. This represents the real-time rotational speed of the gear, in r / min. This represents the real-time load torque of the gear, expressed in N·m. The speed and pressure weighting coefficients are: The load pressure weighting coefficient and the pressure weighting coefficient are both predetermined through bench calibration tests. By coordinating the adjustment of flow rate and pressure, the injection pressure is increased at high speeds to overcome the high-speed airflow barrier on the tooth surface and ensure the precise entry of the nanofluid into the meshing contact area. At low speeds, the injection pressure is reduced to decrease fuel supply energy consumption. Compared with the prior art, the beneficial effects of the present invention are: This invention employs a microtexture array with gradually varying density in the meshing area of ​​the tooth surface. Utilizing the microscopic cavity structure of circular micro-pits, dynamic oil storage is achieved. During the non-meshing phase, the micro-pits store a nanofluid composite lubricating medium. During the meshing contact phase, the micro-pits in the contact area release the stored lubricating medium under the pressure of the tooth surface, continuously replenishing oil to the periphery of the contact area, filling areas where the oil film has sheared and broken, and maintaining the continuity and load-bearing capacity of the oil film. The higher texture density on the meshing side allows for the pre-storage of sufficient lubricating medium, adapting to changes in oil film demand during the meshing process, and increasing the oil film thickness compared to a smooth tooth surface.

[0017] This invention employs a nanofluid composite lubricating medium modified with highly thermally conductive nanoparticles, which can efficiently conduct the instantaneous frictional heat generated by gear meshing. The highly thermally conductive nanoparticles can also enhance the convective heat transfer effect within the oil through Brownian motion, accelerating the diffusion of heat from the meshing zone to the main body of the oil. Combined with a directional injection oil supply method, the low-temperature nanofluid is continuously injected into the high-temperature meshing zone, rapidly carrying away the frictional heat.

[0018] This invention is not a simple combination of microtexturing and nanofluid technology, but rather a synergistic effect achieved through the matching of their structures and performance: On one hand, the micro-pit structure of the tooth surface microtexture can capture and retain highly thermally conductive nanoparticles, preventing them from being rapidly lost with the oil under high-speed conditions. This allows the highly thermally conductive nanoparticles to be stably enriched in the meshing contact area, continuously enhancing heat transfer and overcoming the technical bottleneck of low particle retention rate when using nanofluid alone. The highly thermally conductive nanoparticles can fill the pits in the microtexture, acting as a microscopic rolling bearing during meshing, further reducing the tooth surface friction coefficient. Simultaneously, the high thermal conductivity of the nanofluid can quickly dissipate the heat from the oil stored inside the microtexture, preventing localized heat accumulation. The synergistic effect of these two technologies results in superior friction reduction and heat dissipation compared to the combination of individual technologies. Attached Figure Description

[0019] Figure 1 This is a front view of the present invention, where the microstructure unit is a circular micro-dimple structure. Figure 2 This is a front view of the gear pair and oil supply unit structure of the present invention. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0021] Please see Figures 1-2 This invention provides a microtextured nanofluid electric drive gear lubrication and heat dissipation system, which is applied to the parallel shaft cylindrical gear pair of the electric drive reducer of new energy vehicles. It includes a gear pair that meshes with each other, an oil supply unit, an oil storage unit, an adaptive control unit, an operating condition detection module, and a circulating cooling and filtering unit.

[0022] The gear pair consists of a pair of involute cylindrical spur gears with a module of 2.5 mm, 20 and 40 teeth respectively, a tooth width of 30 mm, a rated input shaft speed of 12000 r / min, and a rated output torque of 300 N·m. The meshing areas of the two gears are uniformly covered with a microtexture array, which is composed of several regularly arranged circular micro-dimple units. In this embodiment, the diameter of a single circular micro-dimple unit is 80 μm, the depth is 20 μm, and the microtexture occupies 15% of the area of ​​the meshing area. The microtexture array is arranged with a gradually changing density along the pitch line of the tooth surface: the microtexture density is highest near the pitch line, and the microtexture density on the meshing side is 120 units / mm. 2 The microtexture density on the biting side is 60 microtextures / mm. 2 The density gradually decreases from the pitch line towards the tooth root and tooth tip.

[0023] The oil storage unit is a sealed oil tank that stores a nanofluid composite lubricating medium. In this embodiment, the base gear oil is 75W-90 vehicle gear oil, and the high thermal conductivity nanoparticles are nano-alumina particles with a particle size of 30-50 nm, with a mass fraction of 1.5%. After surface modification treatment with a silane coupling agent, the high thermal conductivity nanoparticles are prepared into a stable nanofluid through mechanical stirring combined with 60 min of ultrasonic dispersion. The thermal conductivity at room temperature is increased by approximately 22% compared to the base gear oil.

[0024] The oil supply unit includes a variable frequency oil pump, a flow regulating valve, and two sets of injection nozzles. The input end of the variable frequency oil pump is connected to the bottom of the oil storage unit, and the output end is connected to the injection nozzles via the flow regulating valve. The two sets of injection nozzles are respectively positioned facing the two meshing sides of the gear pair, with the nozzle outlet direction forming a 30° angle with the tangent direction of the gear teeth, ensuring that the nanofluid is accurately injected into the meshing contact area. Both the variable frequency oil pump and the flow regulating valve receive control signals from the adaptive control unit to collaboratively adjust the oil supply flow rate and injection pressure.

[0025] The operating condition detection module includes a speed sensor, a torque sensor, an oil temperature sensor, and a tooth surface temperature sensor. The speed and torque sensors are integrated and mounted on the gear input shaft to collect gear speed and input torque in real time. The oil temperature sensor is installed inside the oil reservoir to monitor the overall temperature of the lubricating medium. The tooth surface temperature sensor is an infrared temperature sensor, positioned directly opposite the meshing side of the gear teeth, to collect the tooth surface operating temperature non-contactly. The signal output terminals of each sensor are connected to an adaptive control unit.

[0026] The input end of the circulating cooling filter unit is connected to the oil return port at the bottom of the gearbox, and the output end is connected to the oil storage unit. The unit is equipped with a filter element with a precision of 5μm and a plate heat exchanger. The returned lubricating medium is filtered to remove wear debris and impurities, cooled down by the heat exchanger, and then sent back to the oil storage unit for recycling.

[0027] Furthermore, the single-pit volume and tooth surface density of the microtextured array are matched with the mass fraction of high thermal conductivity nanoparticles in the nanofluid. In the non-meshing stage, the micro-pits retain high thermal conductivity nanoparticles and base oil through the capillary capture effect of the micro-cavities, causing the high thermal conductivity nanoparticles to be locally enriched in the meshing area of ​​the tooth surface. In the meshing contact stage, the pressure-bearing micro-pits release the lubricating medium enriched with nanoparticles. On the one hand, this fills the oil film shear fracture area to maintain the oil film continuity and load-bearing capacity. On the other hand, the high thermal conductivity nanoparticles form micro-rolling support at the tooth surface contact interface to reduce the friction coefficient. At the same time, they fill the micro gaps at the contact interface to strengthen the interface heat conduction path, thus achieving a synergistic effect of friction reduction and heat dissipation.

[0028] Furthermore, the filter element pore size, the average particle size of the high thermal conductivity nanoparticles, and the diameter of the microtextured micro-pits in the circulating cooling filter unit satisfy a hierarchical size matching relationship: In the formula: The filter element pore size is expressed in μm. The average particle size of the high thermal conductivity nanoparticles is expressed in nm. The diameter of the micro-pit is in μm. When the returning lubricating medium is filtered through the filter element, wear debris with a particle size larger than the filter element pore size is trapped, while high thermal conductivity nanoparticles with a particle size smaller than the filter element pore size are all returned to the oil storage unit along with the oil. This avoids the loss of nanoparticles during circulation and prevents large-diameter wear debris from entering the micro-pits and causing blockage, thus ensuring the long-term stability of the dynamic oil storage function of the micro-texture.

[0029] The adaptive control algorithm simultaneously calculates the target fuel supply flow rate and the target injection pressure, where the target injection pressure... The calculation formula is: In the formula: The target injection pressure is expressed in MPa. The reference injection pressure is 0.2~0.5 MPa. This represents the real-time rotational speed of the gear, in r / min. This represents the real-time load torque of the gear, expressed in N·m. The speed and pressure weighting coefficients are: The load pressure weighting coefficient is determined in advance through bench calibration tests. By coordinating the adjustment of flow rate and pressure, the injection pressure is increased under high speed conditions to overcome the high-speed airflow barrier on the tooth surface and ensure that the nanofluid accurately enters the meshing contact area. Under low speed conditions, the injection pressure is reduced to reduce fuel supply energy consumption.

[0030] The adaptive control unit adopts an on-board microcontroller with a built-in adaptive control algorithm. It calculates the target oil supply parameters based on the real-time collected operating parameters and outputs a PWM control signal to adjust the speed of the variable frequency oil pump and the opening of the flow regulating valve, thereby realizing the dynamic adjustment of the oil supply flow and pressure.

[0031] The system described in this embodiment operates as follows: During gear operation, the operating condition detection module collects real-time data on speed, torque, oil temperature, and gear surface temperature, and transmits this data to the adaptive control unit. The adaptive control unit calculates the target oil supply flow rate according to the formula: In this embodiment, the determination is achieved through bench calibration. =0.0002 L·min / (r·min)), =0.001L / (min·N·m), =0.05L / (min·℃), reference temperature Set to 85℃.

[0032] The injection pressure-related parameters were simultaneously determined through bench calibration: reference injection pressure P0 = 0.3 MPa, and speed-pressure weighting coefficient k4 = 2 × 10⁻⁶. -5 MPa / (r·min -1 The load pressure weighting coefficient K5 = 1 × 10 -4 MPa / (N·m).

[0033] When the gear is running under rated conditions (12000 r / min, 300 N·m), the target injection pressure is calculated. The adaptive control unit synchronously adjusts the output pressure of the variable frequency oil pump and the nozzle opening, so that the oil supply flow and injection pressure are matched to the lubrication and heat dissipation requirements under rated working conditions.

[0034] When the gear operates under rated conditions (12000 r / min, 300 N·m) and the tooth surface temperature is 95℃, the target oil supply flow rate is calculated. =2.4+0.3+0.5=3.2L / min, the adaptive control unit adjusts the oil supply unit to spray nanofluid into the meshing area at this flow rate.

[0035] The nanofluid sprayed onto the gear teeth partially enters the meshing contact area, while some is stored in the circular micro-pits of the microtexture. During meshing, the micro-pits in the contact area are squeezed and release oil, continuously replenishing the oil film and preventing it from rupturing. Simultaneously, the high thermal conductivity of the nanofluid rapidly conducts away the meshing friction heat. The oil carrying the heat flows back to the circulating cooling and filtration unit at the bottom of the gearbox, and after cooling and filtration, it returns to the oil storage unit for reuse. When the gear tooth surface temperature exceeds 105℃ (the first temperature threshold), the system automatically increases the oil supply by 20% based on the calculated flow rate to enhance heat dissipation; when the gear tooth surface temperature is below 75℃ (the second temperature threshold), the system reduces the oil supply by 30% to reduce oil churning losses.

[0036] Effect Comparison and Verification: Using the same gear pair as in Example 1, and with conventional smooth tooth surface, basic gear oil, and constant flow rate (3L / min) oil injection lubrication as a control, a bench comparison test was conducted under the same rated operating conditions. The results are as follows: The average friction coefficient of the tooth surface in the comparative example was approximately 0.08, while the average friction coefficient of the tooth surface in Example 1 was approximately 0.062, representing a reduction of 22.5% in friction coefficient. The highest stable temperature of the tooth surface in the comparative example is about 112°C, while the highest stable temperature of the tooth surface in Example 1 is about 91°C, resulting in a 21°C reduction in operating temperature rise. After 1000 hours of continuous operation, the comparative example gear tooth surface showed obvious pitting marks, while the tooth surface of Example 1 showed no obvious wear or pitting, with a reduction in tooth surface wear of approximately 60%. The test results demonstrate that this invention significantly improves the wear reduction and heat dissipation performance of electric drive gears, effectively improving their service condition. Example 2 The difference between this embodiment and Embodiment 1 is that the high thermal conductivity nanoparticles are a mixture of graphene oxide and nanodiamond particles in a 1:1 mass ratio, with a total mass fraction of 0.8%. The resulting nanofluid exhibits a thermal conductivity approximately 35% higher than that of the base gear oil. The microtexture features circular micro-dimples with a diameter of 50 μm, a depth of 10 μm, and an area occupancy of 10%. This embodiment is suitable for electric drive gear applications with higher speeds and medium loads, further improving heat exchange efficiency and reducing the impact of the microtexture on tooth surface contact strength.

[0037] Example 3 This embodiment provides a microtextured nanofluidic electric drive gear lubrication and heat dissipation method, based on the system described in Embodiment 1, and specifically includes the following steps: S1. Preparation of nanofluid composite lubricating medium: Select nano-alumina particles with a particle size of 30~50nm, and use silane coupling agent KH550 to modify the surface of the high thermal conductivity nanoparticles to improve their oleophilicity; add the modified nano-alumina particles to 75W-90 base gear oil at a mass fraction of 1.5%, first stir mechanically at a rate of 500r / min for 30min, and then place them in an ultrasonic disperser for ultrasonic dispersion for 60min, with the dispersion temperature controlled at 35℃, to obtain a stable suspended nanofluid composite lubricating medium; S2. Gear Surface Microtexturing: Using a femtosecond laser micromachining device, a circular array of micro-pits is processed in the meshing area of ​​the gear tooth surface according to a preset density gradient arrangement rule; the laser power is set to 5W and the scanning speed is 200mm / s, and micro-pits with a diameter of 80μm and a depth of 20μm are processed; after processing, the tooth surface is lightly polished with diamond polishing paste to remove processing burrs, and then ultrasonically cleaned with anhydrous ethanol for 10 minutes, and then dried for later use; S3. Constructing a lubrication and heat dissipation circuit: Install an oil storage unit, an oil supply unit, a circulating cooling and filtration unit, and various sensors inside the gearbox. Connect the oil pipeline and control circuit. Inject the prepared nanofluid into the oil storage unit and complete the system debugging. S4. Real-time acquisition of operating parameters: During gear operation, the speed sensor, torque sensor, oil temperature sensor and tooth surface temperature sensor acquire operating data in real time at a sampling frequency of 10Hz and transmit it to the adaptive control unit. S5. Adaptive Lubrication and Heat Dissipation Control: After receiving operating condition data, the adaptive control unit calculates the target oil supply flow and injection pressure through the built-in flow calculation formula, and outputs control signals to adjust the speed of the variable frequency oil pump and the opening of the flow regulating valve, so as to accurately supply nanofluid to the meshing area; combined with the dynamic oil storage and film replenishment effect of the tooth surface microtexture and the high thermal conductivity of nanofluid, it achieves efficient friction reduction and enhanced heat dissipation under all operating conditions.

[0038] 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 modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A microtextured nanofluidic electric drive gear lubrication and heat dissipation system, comprising a gear pair meshing with each other, an oil supply unit, and an oil storage unit, wherein the oil supply unit supplies lubricating medium to the meshing area of ​​the gear pair, and the oil storage unit stores the lubricating medium, characterized in that: The gear pair has a microtexture array arranged in the meshing area of ​​each gear tooth surface. The microtexture array is composed of several independent microstructure units arranged in a regular manner, which is used to store the lubricating medium and dynamically replenish the oil film in the tooth surface contact area during gear meshing. The lubricating medium stored in the oil storage unit is a nanofluid composite lubricating medium, which is prepared by dispersing and stabilizing base gear oil and high thermal conductivity nanoparticles. The output end of the oil supply unit is correspondingly set on the meshing side of the gear pair and is used to spray the nanofluid composite lubricating medium onto the meshing tooth surface. The system also includes an adaptive control unit. The input end of the adaptive control unit is connected to the gear working condition detection module, and the output end controls the connection to the oil supply unit.

2. The microtextured nanofluidic electric drive gear lubrication and heat dissipation system according to claim 1, characterized in that: The microstructure unit of the microtexture array is a circular micro-dimple, with a diameter of 20-200 μm and a depth of 5-50 μm. The microtexture occupies 5%-30% of the area in the meshing region. The microtexture array is arranged with a gradual change in density along the pitch line of the tooth surface, and the microtexture density on the meshing side is greater than that on the disengaging side. The single-dimple volume and tooth surface density of the microtexture array are matched with the mass fraction of high thermal conductivity nanoparticles in the nanofluid. In the non-meshing stage, the micro-dimples capture and retain high thermal conductivity nanoparticles, making the local particle concentration of the lubricating medium in the pit higher than the particle concentration of the free oil on the tooth surface. In the meshing contact stage, the pressure-bearing micro-dimples release high-concentration oil containing particles, and simultaneously form an oil film completion structure and a micro-rolling friction reduction structure at the tooth surface contact interface.

3. The microtextured nanofluidic electric drive gear lubrication and heat dissipation system according to claim 1, characterized in that: The high thermal conductivity nanoparticles are one or more of graphene oxide, nano-alumina, and nanodiamond, with a particle size of 10~100nm, and the mass fraction of the high thermal conductivity nanoparticles in the base gear oil is 0.1%~5%.

4. The microtextured nanofluidic electric drive gear lubrication and heat dissipation system according to claim 1, characterized in that: The oil supply unit includes a variable frequency oil pump, a flow regulating valve, and at least one set of injection nozzles. The injection nozzles are positioned directly opposite the meshing side of the gear pair. Both the variable frequency oil pump and the flow regulating valve receive control signals from the adaptive control unit.

5. The microtextured nanofluidic electric drive gear lubrication and heat dissipation system according to claim 1, characterized in that: The gear condition detection module includes a speed sensor, a torque sensor, an oil temperature sensor, and a tooth surface temperature sensor, which are used to collect real-time gear speed, load torque, lubricating oil temperature, and tooth surface working temperature and transmit them to the adaptive control unit.

6. The microtextured nanofluidic electric drive gear lubrication and heat dissipation system according to claim 1, characterized in that: The system also includes a circulating cooling and filtration unit. The input end of the circulating cooling and filtration unit is connected to the oil return port of the gearbox, and the output end is connected to the oil storage unit. It is used to filter and remove impurities from the returned nanofluid composite lubricating medium and cool it down before sending it back to the oil storage unit for recycling.

7. A method for lubrication and heat dissipation of microtextured nanofluidic electric drive gears, characterized in that, The microtextured nanofluidic electric drive gear lubrication and heat dissipation system as described in any one of claims 1-6 includes the following steps: S1 Preparation of nanofluid composite lubricating medium: Select high thermal conductivity nanoparticles and base gear oil. After surface modification of the high thermal conductivity nanoparticles, add them to the base gear oil and disperse them by ultrasonication to obtain a stable suspended nanofluid composite lubricating medium. S2. Tooth surface micro-texture processing: Using laser micro-machining technology, a micro-texture array with a preset arrangement is formed in the meshing area of ​​the tooth surface of the electric drive gear, so that the tooth surface has the ability to dynamically store oil and replenish oil film during the meshing process. S3. Constructing a lubrication and heat dissipation circuit: Assemble a lubrication and heat dissipation circuit including an oil storage unit, an oil supply unit, and a working condition detection module, and inject the prepared nanofluid composite lubricating medium into the oil storage unit. S4. Real-time acquisition of operating parameters: During gear operation, the operating parameters such as gear speed, load torque, lubricating oil temperature and tooth surface temperature are collected in real time through the operating condition detection module and transmitted to the control terminal. S5. Adaptive Lubrication and Heat Dissipation Control: Based on the received real-time operating parameters, the control unit calculates the target oil supply parameters through an adaptive control algorithm, outputs a control signal to adjust the oil supply flow and injection pressure of the oil supply unit, and precisely supplies nanofluid composite lubricating medium to the gear meshing area. Combined with the dynamic oil storage and film replenishment effect of the tooth surface microtexture and the high thermal conductivity of nanofluid, friction reduction and enhanced heat dissipation under different operating conditions are achieved.

8. The method for lubrication and heat dissipation of microtextured nanofluidic electric drive gears according to claim 7, characterized in that: In step S5, the formula for calculating the target oil supply flow rate is: In the formula: The target oil supply flow rate is expressed in L / min. This represents the real-time rotational speed of the gear, in r / min. This represents the real-time load torque of the gear, in N·m. This is the real-time tooth surface temperature, in °C. The preset reference operating temperature, in °C. 、 、 The weighting coefficients are rotational speed, load, and temperature, which are determined in advance through bench calibration tests. In step S2, the microtexture array is arranged with a gradual change in density along the tooth height direction. The microtexture density gradually increases from the tooth root to the pitch line and gradually decreases from the pitch line to the tooth tip. The ultrasonic dispersion treatment time is 30~120min and the treatment temperature is controlled at 20~50℃.

9. The method for lubrication and heat dissipation of microtextured nanofluidic electric drive gears according to claim 7, characterized in that: In step S5, the basic target oil supply flow rate is calculated using a formula. Q Subsequently, a graded flow correction is performed based on the real-time tooth surface temperature to obtain the final oil supply flow rate. Q The correction rule satisfies the following formula: In the formula: The preset over-temperature warning threshold is set to 100℃~110℃. The preset low-temperature energy-saving threshold is set at 70℃~80℃. This is the overheating flow booster coefficient, with a value ranging from 15% to 25%. The low-temperature flow reduction coefficient is taken as 25%~35%, and satisfies the following conditions: .

10. A method for lubrication and heat dissipation of microtextured nanofluidic electric drive gears according to claim 7, characterized in that: In step S5, the adaptive control algorithm simultaneously calculates the target fuel supply flow rate and the target injection pressure, wherein the target injection pressure The calculation formula is: In the formula: The target injection pressure is expressed in MPa. The reference injection pressure is 0.2~0.5 MPa. This represents the real-time rotational speed of the gear, in r / min. This represents the real-time load torque of the gear, expressed in N·m. The speed and pressure weighting coefficients are: The load pressure weighting coefficient is determined in advance through bench calibration tests. By coordinating the adjustment of flow rate and pressure, the injection pressure is increased under high speed conditions to overcome the high-speed airflow barrier on the tooth surface and ensure that the nanofluid accurately enters the meshing contact area. Under low speed conditions, the injection pressure is reduced to reduce fuel supply energy consumption.

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