Hydraulic valve with bionic lubricating structure and ultrafast laser preparation method and application of hydraulic valve

Abstract

The invention discloses a hydraulic valve with a bionic lubricating structure and an ultrafast laser preparation method and application of the hydraulic valve, and relates to the technical field of metal element manufacturing and processing industry. The ultrafast laser preparation method comprises the steps that a bionic structure is prepared according to the fish scale morphology, the bionic structure comprises a V-shaped groove and a horizontal ridge, the horizontal ridge is connected with one end of the top of the V-shaped groove, and the V-shaped groove and the horizontal ridge are arranged as a unit array; valve element machining masks are prepared according to the bionic structures; and the valve element machining mask and the valve element machining area are placed in an overlapped mode, and ultrafast laser shock peening treatment is conducted on the valve element machining mask. The V-shaped groove realizes active transportation of a lubricating oil film, and can realize minimum friction on the basis of minimum leakage of lubricating oil and sealing keeping, so that the lubricating effect is ensured. Besides, the oil storage space of the V-shaped groove can effectively block pollutant particles larger than 10 micrometers, the average friction coefficient is reduced by 35% or above, and therefore the abrasion resistance and the lubricating performance of the valve body are improved.

Description

Technical Field

[0001] This invention relates to the field of metal component manufacturing and processing technology, and more specifically, to a hydraulic valve with a biomimetic lubrication structure, its ultrafast laser preparation method, and its application. Background Technology

[0002] Hydraulic valves, as core control components of fluid transmission systems, regulate fluid direction, pressure, and flow rate, playing a crucial role in achieving precise control of the system's state. However, because the friction pair formed by the valve core and valve sleeve is subjected to harsh conditions of high pressure and high frequency for extended periods, boundary lubrication failure is easily triggered, leading to adhesive wear and increased energy consumption, thus affecting the safety and reliability of the fluid transmission system. Currently, the industry uses traditional surface coatings (such as CrN, DLC, etc.) to improve wear resistance, but the bonding strength between the coating and the substrate is insufficient, making it prone to peeling under alternating loads and exhibiting poor environmental compatibility. Alternatively, mechanical micromachining (such as rolling and etching) is employed, but its low processing precision makes it difficult to achieve micron-level complex morphology control and form optimized lubrication microstructures.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulic valve with a biomimetic lubrication structure, its ultrafast laser preparation method, and its application. This invention utilizes an ultrafast laser to generate a high-pressure shock wave on the material surface, causing the material to undergo plastic deformation. By applying a microgroove design similar to fish scales, a composite micro / nano structure with gradient wettability is constructed on the surface of the friction pair. Moreover, it can achieve precise control of the deformation after boundary lubrication enhancement, thereby achieving high-precision, low-damage improvement of the lubrication performance of the hydraulic valve.

[0005] This invention is implemented as follows: In a first aspect, the present invention provides an ultrafast laser fabrication method for a hydraulic valve having a biomimetic lubrication structure, comprising: A biomimetic structure is prepared based on the fish scale morphology. The biomimetic structure includes a V-shaped groove and a horizontal ridge. The horizontal ridge is connected to the top end of the V-shaped groove, and the V-shaped groove and the horizontal ridge are arranged as a unit array. The area where the valve core and valve sleeve of a hydraulic valve contact each other is designated as a friction pair. The area of ​​the valve core corresponding to the friction pair is designated as the valve core machining area, and the area of ​​the valve sleeve corresponding to the friction pair is designated as the valve sleeve machining area. The valve core processing mask and the valve sleeve processing mask are prepared according to the biomimetic structure described above. The valve core processing mask is placed on the same side as the valve core processing area, and the valve sleeve processing mask is placed on the same side as the valve sleeve processing area. The valve core processing mask and the valve sleeve processing mask are subjected to ultrafast laser shock strengthening treatment respectively, so that the outer surface of the valve core and the inner surface of the valve sleeve have a biomimetic lubrication structure. The valve core and the valve assembly are assembled to form a hydraulic valve with a biomimetic lubrication structure.

[0006] In an optional embodiment, the widths of the V-shaped groove and the horizontal ridge are 1:0.8-1.2.

[0007] In an optional embodiment, the opening spacing of the V-shaped groove is 50-150 μm, and the depth is 20-50 μm; And / or, the angle between the line connecting the midpoint of the opening of the V-shaped groove and the bottom point of the depth of the V-shaped groove and the top horizontal line of the V-shaped groove is 88-92°; And / or, the included angle between the two sidewalls of the V-shaped groove is >85° In an optional embodiment, the V-groove and the horizontal ridge extend in a direction parallel to the axial direction of the valve core.

[0008] In an optional embodiment, the parameters of the ultrafast laser shock peening process include: pulse energy of 10-200 μJ, pulse width of 100 fs-400 fs, wavelength of 1000-1050 nm, repetition frequency of 40-60 kHz, number of scans of 1, scanning speed of 200-400 mm / s, spot diameter of 20-40 mm, and overlap rate of 33%-66%.

[0009] In an optional implementation, the ultrafast laser shock peening process is carried out using an "S"-shaped processing trajectory and a single-line multiple scanning method, that is, the laser beam scans repeatedly N times along the designed path of the single V-shaped groove, gradually deepening to the target depth.

[0010] In an optional embodiment, before performing the ultrafast laser shock strengthening process, the valve core processing mask and the valve core processing area are calibrated, and the valve sleeve processing mask and the valve sleeve processing area are calibrated, wherein the linear positioning accuracy is ≤ ±1μm and the repeatability positioning accuracy is ≤ ±0.5μm; And / or, the ultrafast laser shock peening process is performed under inert gas protection.

[0011] In an optional embodiment, before performing the ultrafast laser shock peening treatment, the valve core and the valve sleeve are further polished and pre-cleaned; after performing the ultrafast laser shock peening treatment, the valve core and the valve sleeve are further cleaned.

[0012] In an optional embodiment, the polishing includes precision polishing of the cleaned valve core surface to a surface roughness of <0.1 μm; And / or, the pre-cleaning includes ultrasonic cleaning with acetone and anhydrous ethanol for 10-20 minutes in sequence, followed by drying with nitrogen. And / or, the re-cleaning includes first ultrasonic cleaning with anhydrous ethanol for 10-20 minutes, followed by rinsing with deionized water, and finally drying with nitrogen.

[0013] Secondly, the present invention provides a hydraulic valve with a biomimetic lubrication structure, which is prepared by an ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure as described in any of the foregoing embodiments.

[0014] Thirdly, the present invention provides the application of a hydraulic valve with a biomimetic lubrication structure as described in any of the foregoing embodiments in the preparation of a fluid transmission system.

[0015] The present invention has the following beneficial effects: The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure provided by this invention prepares a biomimetic structure with V-shaped grooves and horizontal ridges by simulating fish scale morphology. Ultrafast laser shock peening is then applied to the friction pair between the valve core and valve sleeve, thereby forming a pre-defined biomimetic structure on the surface of the valve core. Since the extension direction of the V-shaped groove corresponds to the axial direction of the valve core, i.e., it is consistent with the flow direction of the lubricating oil, the V-shaped groove enables active transport of the lubricating oil film. This minimizes friction while maintaining a seal with minimal lubricating oil leakage, ensuring effective lubrication. Furthermore, the oil storage space of the V-shaped groove in this invention can effectively block contaminant particles larger than 10 μm, reducing the average coefficient of friction by more than 35%, thereby improving the wear resistance of the valve body and achieving high-precision, low-damage improvement of the hydraulic valve's lubrication performance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A process flow diagram of the ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure provided by the present invention; Figure 2 A schematic diagram of the structure of the hydraulic valve with a biomimetic lubrication structure provided by the present invention; Figure 3 A schematic diagram of the biomimetic structure in the hydraulic valve with a biomimetic lubrication structure provided by the present invention; Figure 4 A schematic diagram illustrating the fabrication process of a hydraulic valve with a biomimetic lubrication structure provided by the present invention; Figure 5 A schematic diagram of the fretting wear testing device provided by the present invention; Figure 6 Comparison of fretting wear results for different examples provided by the present invention, wherein (a) is a comparison of the average coefficient of friction (COF) of the hydraulic valve body under different examples, and (b) is a comparison of the wear amount (×10) of the hydraulic valve body under different examples. 5 μm 3 Comparison chart.

[0018] Icons: 100 - Hydraulic valve with biomimetic lubrication structure; 101 - Top cover; 102 - Upper spring; 103 - Valve core; 104 - Valve sleeve; 105 - Lower spring; 106 - Lower cover; 200 - Bionic structure; 201 - V-groove; 202 - Horizontal ridge. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] Please see Figure 1 This invention provides an ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure, comprising the following steps: S1. Prepare biomimetic structure 200.

[0021] Please see Figure 3 A biomimetic structure 200 was fabricated based on the fish scale morphology. The biomimetic structure 200 includes a V-shaped groove 201 and a horizontal ridge 202. The horizontal ridge 202 is connected to the top end of the V-shaped groove 201. The width ratio of the V-shaped groove 201 and the horizontal ridge 202 is 1:1. The V-shaped groove 201 and the horizontal ridge 202 are arranged in a unit array. The opening spacing of the V-shaped groove 201 is 50-150μm, and the depth is 20-50μm. The angle between the line connecting the midpoint of the opening of the V-shaped groove 201 and the bottom point of the depth of the V-shaped groove 201 and the horizontal line at the top of the V-shaped groove 201 is 88-92°. The angle between the two side walls of the V-shaped groove 201 is >85°.

[0022] S2. Prepare the mask.

[0023] Please see Figure 2The hydraulic valve structure includes an upper cover 101, an upper spring 102, a valve core 103, a valve sleeve 104, a lower spring 105, and a lower cover 106. The area where the valve core 103 and the valve sleeve 104 contact each other is a friction pair. The area of ​​the valve core 103 corresponding to the friction pair is the valve core 103 machining area, and the area of ​​the valve sleeve 104 corresponding to the friction pair is the valve sleeve 104 machining area. Machining masks for the valve core 103 and the valve sleeve 104 are prepared according to the biomimetic structure 200.

[0024] S3. Polish and pre-clean the valve core 103 and valve sleeve 104.

[0025] After cleaning, the surface of the valve core 103 is finely polished using 2000-5000 grit sandpaper to remove the oxide layer, micro-scratches and other surface defects, thereby improving the surface smoothness and finish. At the same time, during each polishing stage, an optical microscope or surface roughness meter is used to check to ensure that the surface roughness meets the requirements (Ra<0.1μm) to ensure the processing effect of ultrafast laser.

[0026] After polishing, place the polished valve core 103 into an ultrasonic cleaner and use acetone and anhydrous ethanol for ultrasonic cleaning for 10-20 minutes to remove residual polishing agent and grease from the surface. Dry it with nitrogen and store it in an ultra-clean environment for later use.

[0027] S4, Ultrafast Laser Shock Enhancement Processing.

[0028] Please see Figure 4 The machining mask for valve core 103 is placed in conjunction with the machining area of ​​valve core 103, and the machining mask for valve sleeve 104 is placed in conjunction with the machining area of ​​valve sleeve 104. After the overlap, the machining mask for valve core 103 and the machining area of ​​valve core 103 are calibrated, and the machining mask for valve sleeve 104 and the machining area of ​​valve sleeve 104 are calibrated at the same time. The linear positioning accuracy is ≤ ±1μm, and the repeatability is ≤ ±0.5μm.

[0029] Ultrafast laser shock peening treatment was applied to the machining mask of valve core 103 and the machining mask of valve sleeve 104 respectively, so that the outer surface of valve core 103 and the inner surface of valve sleeve 104 both have a biomimetic lubrication structure.

[0030] Before starting the laser, necessary equipment calibration is performed to ensure that the laser beam spot size, focal position, and beam quality meet the preset requirements. Testing is conducted using calibration samples to verify that the settings meet the expected results. After confirming that the settings are correct, the valve core 103 or valve sleeve 104 of the hydraulic valve is fixed on the laser's processing platform. The processing path and laser parameters are set, ensuring that the entire area of ​​the valve core 103 and valve sleeve 104 of the hydraulic valve is uniformly covered. The laser is then started, and ultrafast laser shock peening treatment is performed on the processing areas of the valve core 103 and valve sleeve 104 according to the preset parameters and scanning path. During processing, the stability of the laser output and the surface condition are monitored in real time. Appropriate parameter adjustments can be made if necessary. The processing platform ensures the stability and consistency of the processing process, with linear positioning accuracy ≤ ±1μm and repeatability ≤ ±0.5μm. Regarding the processing environment, an inert gas (such as N2) is used to protect the metal and prevent oxidation.

[0031] The parameters for ultrafast laser shock peening include: pulse energy of 10-200 μJ, pulse width of 100-400 fs, wavelength of 1000-1050 nm, repetition frequency of 40-60 kHz, number of scans of 1, scanning speed of 200-400 mm / s, spot diameter of 20-40 μm, and overlap rate of 33%-66%, ensuring the continuity and smoothness of the groove.

[0032] Ultrafast laser shock peening process uses an "S" shaped processing trajectory and a single-line multiple scanning method, that is, the laser beam scans repeatedly N times along the designed single V-shaped groove 201 path, gradually deepening to the target depth.

[0033] The V-shaped groove 201 in this invention is formed by layered cumulative ablation. The first scan generates a shallow U-shaped groove with a depth of about 4μm. After 5 scans, it transitions into a V-shaped profile, and finally reaches the target depth after 10 scans. There is no slag residue at the bottom of the formed groove, and the surface roughness Ra < 0.8μm, which meets the hydrodynamic lubrication requirements of the friction pair of the hydraulic valve.

[0034] The valve core 103 that has been processed needs to undergo a second cleaning process using a low-power laser (5μJ / pulse) to remove microburrs.

[0035] S5. Clean the valve core 103 and valve sleeve 104 again.

[0036] After ultrafast laser shock peening, the surfaces of the valve core 103 and valve sleeve 104 processing areas may retain microparticles, molten material, or other impurities. To ensure the integrity of the surface micro / nano structure and wear resistance, the surfaces must be thoroughly cleaned to remove all processing residues and further optimize the surface condition of the valve core 103 and valve sleeve 104 processing areas after strengthening. The valve core 103 and valve sleeve 104 are placed in an ultrasonic cleaner and cleaned with ethanol solvent for 10-20 minutes to ensure the removal of fine particles, processing residues, or other contaminants adhering to the surface. After cleaning, the conduit surface is rinsed multiple times with high-purity deionized water to thoroughly remove solvent and residual impurities. After cleaning, the conduit junction surface is dried with high-purity dry nitrogen gas (purity ≥99.99%) to remove any remaining moisture or solvent, and then stored in a vacuum drying oven (50℃, -0.1MPa) for later use.

[0037] S6. Assemble to form a hydraulic valve.

[0038] The valve core 103 and valve sleeve 104 are assembled to form a hydraulic valve 100 with a biomimetic lubrication structure.

[0039] The hydraulic valve 100 with a biomimetic lubrication structure, fabricated using the aforementioned ultrafast laser fabrication method, exhibits a good coefficient of friction and low wear rate. It can be widely applied in the fabrication of various fluid transmission systems.

[0040] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0041] Example 1 This invention provides an ultrafast laser fabrication method for a hydraulic valve 100 with a biomimetic lubrication structure, comprising the following steps: S1. Prepare biomimetic structure 200.

[0042] A biomimetic structure 200 is fabricated based on the fish scale morphology. The biomimetic structure 200 includes a V-shaped groove 201 and a horizontal ridge 202. The horizontal ridge 202 is connected to the top end of the V-shaped groove 201. The width ratio of the V-shaped groove 201 to the horizontal ridge 202 is 1:1. The V-shaped groove 201 and the horizontal ridge 202 are arranged in a unit array. The opening spacing of the V-shaped groove 201 is 100±2μm, and the depth is 40±1.5μm. The angle between the line connecting the midpoint of the opening of the V-shaped groove 201 and the bottom point of the depth of the V-shaped groove 201 and the horizontal line at the top of the V-shaped groove 201 is 90±2°. The angle between the two side walls of the V-shaped groove 201 is >85°.

[0043] S2. Prepare the mask.

[0044] The area where the valve core 103 and valve sleeve 104 of the hydraulic valve contact is set as a friction pair. The area of ​​the valve core 103 corresponding to the friction pair is the valve core 103 machining area, and the area of ​​the valve sleeve 104 corresponding to the friction pair is the valve sleeve 104 machining area. The valve core 103 machining mask and the valve sleeve 104 machining mask are prepared according to the biomimetic structure 200.

[0045] S3. Polish and pre-clean the valve core 103 and valve sleeve 104.

[0046] The surface of the cleaned valve core 103 was finely polished using 3000-grit sandpaper. At each polishing stage, an optical microscope or surface roughness meter was used to check the surface roughness to ensure it met the requirements (Ra < 0.1 μm). After polishing, the polished valve core 103 was placed in an ultrasonic cleaner and ultrasonically cleaned for 15 minutes with acetone and anhydrous ethanol to remove residual polishing agent and grease. It was then dried with nitrogen and stored in an ultra-clean environment for later use.

[0047] S4, Ultrafast Laser Shock Enhancement Processing.

[0048] The machining mask for valve core 103 is placed in conjunction with the machining area of ​​valve core 103, and the machining mask for valve sleeve 104 is placed in conjunction with the machining area of ​​valve sleeve 104. After the two are placed in conjunction, the machining mask for valve core 103 and the machining area of ​​valve core 103 are calibrated, and the machining mask for valve sleeve 104 and the machining area of ​​valve sleeve 104 are calibrated at the same time. The linear positioning accuracy is ≤ ±1μm, and the repeatability is ≤ ±0.5μm.

[0049] In an inert gas atmosphere, ultrafast laser shock peening was performed on the processing masks for valve core 103 and valve sleeve 104, respectively. First, valve core 103 was fixed in a vacuum fixture. The ultrafast laser beam was controlled by a galvanometer system, moving in a parallel linear motion along the axial direction of valve core 103 at a scanning speed of 300 mm / s. The parameters for ultrafast laser shock peening included: pulse energy 25 μJ, pulse width 400 fs, wavelength 1030 nm, repetition rate 50 kHz, one scan, spot diameter 30 μm, and overlap rate 50%. Defocusing was achieved by positioning the focal point 0.1 mm below the surface, resulting in a Gaussian energy distribution. Each groove required 10 scans according to the above parameters to ensure the formation of steep V-shaped sidewalls during material delamination and ablation. High-purity nitrogen gas (flow rate 15 L / min, oxygen concentration < 100 ppm) was continuously introduced during processing to suppress oxidation.

[0050] The V-shaped groove 201 in this invention is formed by layered cumulative ablation. The first scan generates a shallow U-shaped groove with a depth of about 4μm. After 5 scans, it transitions into a V-shaped profile, and finally reaches the target depth after 10 scans. There is no slag residue at the bottom of the formed groove, and the surface roughness Ra < 0.8μm, which meets the hydrodynamic lubrication requirements of the friction pair of the hydraulic valve.

[0051] The valve core 103 that has been processed needs to undergo a second cleaning process using a low-power laser (5μJ / pulse) to remove microburrs.

[0052] S5. Clean the valve core 103 and valve sleeve 104 again.

[0053] After ultrafast laser shock peening, valve core 103 and valve sleeve 104 are placed in an ultrasonic cleaner and cleaned with ethanol solvent for 15 minutes. After cleaning, the surface of the conduit is rinsed multiple times with high-purity deionized water. After cleaning, the surface of the conduit junction is dried with high-purity dry nitrogen gas (purity ≥99.99%) and stored in a vacuum drying oven (50℃, -0.1MPa) for later use.

[0054] S6. Assemble to form a hydraulic valve.

[0055] The valve core 103 and valve sleeve 104 are assembled to form a hydraulic valve 100 with a biomimetic lubrication structure.

[0056] Comparative Example 1 This comparative example provides an untreated hydraulic valve, which directly uses the hydraulic valve in Example 1 that has not undergone biomimetic structure ultrafast laser shock strengthening treatment as the untreated hydraulic valve.

[0057] Comparative Example 2 This comparative example provides a hydraulic valve that employs industrial-grade chrome plating to reduce friction. Specifically, it utilizes the same stainless steel material as the present invention and is machined to the same dimensions. After turning and grinding, the surface roughness Ra is controlled at 0.4~0.8μm. For cleaning and degreasing, an alkaline cleaning agent is used for ultrasonic cleaning at 70℃ for 15 minutes to remove surface oil. Simultaneously, electrochemical degreasing is performed in an electrolyte containing sodium hydroxide and sodium carbonate, with the workpiece acting as the cathode, at a current density of 8 A / dm³. 2 The process takes 3 minutes. The material is then acid-washed and activated by immersing in a 12% sulfuric acid solution at room temperature for 45 seconds to remove the surface passivation film, exposing the fresh metal substrate. It is then thoroughly rinsed with deionized water. Finally, chromium plating is performed using a standard chromium plating solution with a composition of 240 g / L chromium anhydride (CrO3) and 2.4 g / L sulfuric acid (H2SO4), at a temperature controlled at 58℃. The workpiece is used as the cathode, and the lead-tin alloy as the anode. A stepped current method is used in the initial stage, starting with 22 A / dm³. 2The current density was applied for 2 minutes of shock plating, then reduced to 55 A / dm. 2 Electroplating was performed using a standard current density. By controlling the electroplating time (approximately 120 minutes in this comparative example), a hard chrome plating layer with a thickness of 20±2μm was obtained on the valve core surface. After cleaning and drying, the valve core was immersed in ISO VG 46 hydraulic oil for later use.

[0058] This comparative example demonstrates the formation of a thick, hard chromium plating layer through electrochemical deposition, which enhances wear resistance due to its high hardness (800-1000 HV) and low coefficient of friction. However, this process suffers from high internal stress in the plating layer, a tendency to generate microcracks, and the potential for crack propagation under cyclic stress to lead to plating peeling, forming abrasive particles, and exacerbating wear.

[0059] Comparative Example 3 This comparative example provides a hydraulic valve that uses a nanosecond laser square pit array to reduce friction. Specifically, it uses the same stainless steel material as the present invention and is machined to the same dimensions. A nanosecond laser with a maximum average power of 20W is used, and a square dot array is designed on the valve core surface. Each micro-pit is a circular blind hole with a designed diameter of 100μm and a center-to-center spacing of 200μm. The processing path involves scanning the laser beam through a galvanometer system, using a point-by-point drilling method. The laser power is set to 15W, the repetition frequency to 20kHz, and a single-pulse drilling mode is used. By controlling the number of pulses, micro-pits with a depth of approximately 30μm are ablated. During processing, compressed air is used for lateral blowing to remove molten material. After processing, the valve is cleaned with acetone in an ultrasonic cleaner for 20 minutes to thoroughly remove molten sputterings and residual particles from the surface. After cleaning and drying, the valve is immersed in ISOVG 46 hydraulic oil for later use.

[0060] This comparative example utilizes nanosecond lasers to process regularly distributed micro-pits as oil reservoirs and wear debris traps. However, due to the significant thermal effect of nanosecond lasers, the material is mainly removed through melting and evaporation, resulting in obvious slag accumulation and heat-affected zones (HAZs) at the edges of the micro-pits. The pit walls may remelt and resolidify, or even generate microcracks. These defects can become fatigue crack initiation points, leading to performance degradation under high-load reciprocating motion.

[0061] Comparative Example 4 This comparative example provides a hydraulic valve that employs a branchless microgroove structure to reduce friction, specifically a series of parallel, straight grooves with a constant cross-sectional shape and size, without any branching network. Specifically, it involves selecting the same stainless steel hydraulic valve as in Example 1, and using the same ultrafast laser processing equipment as this invention to process a series of straight grooves parallel to the axis on the valve core surface. The groove width is designed to be 100 μm, and the groove spacing is 300 μm. The laser beam scans along a straight line. However, no branching structures are processed, and no energy gradient strategy or defocusing LIPSS nanostructures are employed. After ultrafast laser shock strengthening, the valve core 103 and valve sleeve 104 are placed in an ultrasonic cleaner and cleaned with ethanol solvent for 15 minutes. After cleaning, the conduit surface is rinsed multiple times with high-purity deionized water. After cleaning, the conduit junction surface is dried with high-purity dry nitrogen gas (purity ≥99.99%) and stored in a vacuum drying oven (50℃, -0.1MPa) for later use.

[0062] This comparative example uses only a simple, regular microtexture, which can store fluid and remove wear debris, but lacks directional transport capabilities. During reciprocating motion, the fluid tends to flow out from both ends of the groove, and due to the lack of a wettability gradient, the oil film is prone to breakage within the groove, failing to achieve the "continuous pumping and replenishment" effect described in this invention. Therefore, its performance under long-term lubrication and extreme operating conditions is significantly lower than that of this invention.

[0063] Experimental Example 1 Fretting wear tests were conducted on the samples from Example 1 and Comparative Examples 1-4 to evaluate their wear performance. The fretting wear results were compared to obtain a comparison chart of the average coefficient of friction (COF). For details, please refer to... Figure 5The fretting wear performance of specimens after ultrafast laser surface treatment was tested using a self-developed fretting wear tester. After testing, the post-wear morphology was characterized using a white light interferometer and a scanning electron microscope. The fretting wear tester mainly consists of a voice coil motor, displacement sensor, force sensor, test platform, weights, and a monitor. During the test, the guide rail remains free vertically. Weights are then installed, and the displacement amplitude, frequency, and number of cycles are set in the monitor. The voice coil motor is started, driving the test platform to move periodically via a lead screw. During the test, the friction force of the specimen is measured and recorded using the force sensor. After the test, the data is processed to obtain the coefficient of friction (COF) curve. The fretting wear performance parameters were set as follows: friction pair radius 8 mm, normal loading force 10 N, displacement amplitude 120 μm, frequency 5 Hz, and number of cycles 10,000. SEM was used to observe the microstructure, edge quality, and presence of cracks / melting. A contact angle meter was used in the wettability test to evaluate the surface oleophilicity (target: oil contact angle <10°). Tribological performance verification was performed using a reciprocating friction and wear testing machine to simulate the motion of valve core 103. Hydraulic oil, such as ISO VG 32 / 46, was used as the fluid medium. Measurements included: average friction coefficient curve and wear amount (wear track morphology, volume loss).

[0064]

[0065] From the table above and Figure 6 It can be seen that the average friction coefficient of the hydraulic valve core 103 after ultrafast laser processing in Example 1 of this invention is significantly lower than that in Comparative Examples 1-4. Furthermore, to further quantitatively evaluate the wear performance gain of the specimen after ultrafast laser processing with branched microgrooves, the three-dimensional morphology of the wear track was used to extract the cross-sectional contour, and the wear track volume was calculated to obtain the wear amount (×10). 5 μm 3 (Comparison chart) In the embodiment of the present invention, the wear of the hydraulic valve core 103 is also significantly lower than that of comparative examples 1-4.

[0066] The hydraulic valve core 103 provided in the embodiments of the present invention exhibits a significant reduction in average coefficient of friction (COF) and wear compared to traditional industrial-grade chrome plating and nanosecond laser square pit arrays, resulting in a marked improvement in the lubrication performance of the hydraulic valve. By comparing the branched microgroove ultrafast laser process of the present invention with the optimal comparative example (i.e., the unbranched microgroove structure), it can be seen that the average coefficient of friction (COF) is further reduced by 35%, from 0.095 to 0.062, and the wear volume is reduced by 47%, from 5.1 × 10⁻⁶ mm. 5 Up to 2.7×10 5 μm 3The test data fully met the preset targets (average friction coefficient reduction greater than 20%, wear rate reduction greater than 30%), and through observation with fluorescent tracers, the microgroove structure extended the lubricating film retention time to 6.8 times that of the traditional structure.

[0067] In summary, the ultrafast laser fabrication method for the hydraulic valve 100 with a biomimetic lubrication structure provided by this invention prepares a biomimetic structure 200 with V-shaped grooves 201 and horizontal ridges 202 by simulating fish scale morphology. Ultrafast laser shock peening is then applied to the friction pair portion where the valve core 103 and valve sleeve 104 contact, thereby forming a pre-defined biomimetic structure 200 on the surface of the valve core 103. Since the extension direction of the V-shaped grooves 201 corresponds to the axial direction of the valve core 103, i.e., it is consistent with the flow direction of the lubricating oil, the V-shaped grooves 201 achieve active transport of the lubricating oil film. This minimizes friction while maintaining a seal with minimal lubricating oil leakage, ensuring lubrication effectiveness. Furthermore, the oil storage space of the V-shaped grooves 201 in this invention can effectively block contaminant particles >10μm, reducing the average coefficient of friction by more than 35%, thereby improving the wear resistance of the valve body and achieving high-precision, low-damage improvement of the hydraulic valve's lubrication performance.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure, characterized in that, It includes: A biomimetic structure is prepared based on the fish scale morphology. The biomimetic structure includes a V-shaped groove and a horizontal ridge. The horizontal ridge is connected to the top end of the V-shaped groove, and the V-shaped groove and the horizontal ridge are arranged as a unit array. The area where the valve core and valve sleeve of a hydraulic valve contact each other is designated as a friction pair. The area of ​​the valve core corresponding to the friction pair is designated as the valve core machining area, and the area of ​​the valve sleeve corresponding to the friction pair is designated as the valve sleeve machining area. A valve core processing mask and a valve sleeve processing mask are prepared according to the biomimetic structure. The valve core processing mask is placed on the same side as the valve core processing area, and the valve sleeve processing mask is placed on the same side as the valve sleeve processing area. The valve core processing mask and the valve sleeve processing mask are subjected to ultrafast laser shock strengthening treatment, so that the outer surface of the valve core and the inner surface of the valve sleeve both have a biomimetic lubrication structure. The valve core and the valve assembly are assembled to form a hydraulic valve with a biomimetic lubrication structure.

2. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 1, characterized in that, The widths of the V-shaped groove and the horizontal ridge are 1:0.8-1.

2.

3. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 1, characterized in that, The V-shaped groove has an opening spacing of 50-150μm and a depth of 20-50μm; And / or, the angle between the line connecting the midpoint of the opening of the V-shaped groove and the bottom point of the depth of the V-shaped groove and the top horizontal line of the V-shaped groove is 88-92°; And / or, the included angle between the two side walls of the V-shaped groove is >85°.

4. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 1, characterized in that, The V-shaped groove and the horizontal ridge extend in a direction parallel to the axial direction of the valve core.

5. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 1, characterized in that, The parameters of the ultrafast laser shock peening process include: pulse energy of 10-200 μJ, pulse width of 100-400 fs, wavelength of 1000-1050 nm, repetition frequency of 40-60 kHz, number of scans of 1, scanning speed of 200-400 mm / s, spot diameter of 20-40 μm, and overlap rate of 33%-66%.

6. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 5, characterized in that, The ultrafast laser shock peening process employs an "S"-shaped processing trajectory and a single-line multiple-scan method, whereby the laser beam repeatedly scans along the designed path of the single V-shaped groove N times, gradually deepening to the target depth.

7. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 1, characterized in that, Before performing the ultrafast laser shock strengthening process, the valve core processing mask and the valve core processing area are calibrated, and the valve sleeve processing mask and the valve sleeve processing area are calibrated. The linear positioning accuracy is ≤ ±1μm, and the repeatability positioning accuracy is ≤ ±0.5μm. And / or, the ultrafast laser shock peening process is performed under inert gas protection.

8. The ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure according to claim 1, characterized in that, Before performing the ultrafast laser shock blasting treatment, the valve core and valve sleeve are polished and pre-cleaned; after performing the ultrafast laser shock blasting treatment, the valve core and valve sleeve are re-cleaned. The polishing includes precision polishing of the cleaned valve core surface to a surface roughness of <0.1μm; The pre-cleaning process includes ultrasonic cleaning with acetone and anhydrous ethanol for 10-20 minutes in sequence, followed by drying with nitrogen. The re-cleaning process includes ultrasonic cleaning with anhydrous ethanol for 10-20 minutes, followed by rinsing with deionized water, and finally drying with nitrogen.

9. A hydraulic valve with a biomimetic lubrication structure, characterized in that, It is prepared by the ultrafast laser fabrication method for a hydraulic valve with a biomimetic lubrication structure as described in any one of claims 1-8.

10. The application of the hydraulic valve with a biomimetic lubrication structure as described in claim 9 in the preparation of a fluid transmission system.

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