A bearing anti-electric erosion special surface treatment method and bearing

Abstract

The present application relates to the technical field of special surface treatment, and particularly relates to a bearing anti-electricity-erosion special surface treatment method and a bearing, the treatment method comprising special surface treatment and activation, blackening treatment, silane coupling agent micropore modification, 130-140 DEG C high-temperature oil immersion, water-based polyurethane controllable polymerization film sealing, surface finishing and homogenization, and resistivity testing. The design does not need to greatly change the original manufacturing process of the bearing, solves the problems of high cost, difficult manufacturing, uneven film thickness, and poor working condition adaptability of the existing anti-electricity-erosion technology, makes the resistivity of the bearing increase by more than 450 times, the treatment of each component is uniform, has both long-lasting anti-electricity-erosion performance and lubrication compatibility, is suitable for complex working conditions such as vibration impact and multiple disassembly, and is particularly suitable for high-reliability requirement scenes such as wind turbine generators.

Description

Technical Field

[0001] This invention relates to the field of special surface treatment technology, specifically to a special surface treatment method for bearings to resist electro-erosion and a bearing thereof. Background Technology

[0002] Bearing electro-erosion (EEC) is an electrochemical corrosion phenomenon caused by the breakdown of the oil film and the generation of shaft current when current flows through the rolling elements from one raceway to another. This can lead to the failure of the internal oil film of the bearing due to high temperatures, posing a significant threat to the normal operation and safety of equipment, especially in high-reliability applications such as wind turbine generators. To reduce ECC damage, the industry has developed various technical solutions, the core of which is to interrupt the shaft current loop or reduce the shaft current. Widely used solutions include: alumina electrically insulated bearings prepared by spraying processes, hybrid ceramic bearings using ceramic rolling elements, and bearings treated with DLC using PVD (physical vapor deposition) technology. These technologies can all provide some resistance to ECC in specific scenarios, offering diverse options for bearing protection.

[0003] However, existing anti-electro-erosion technologies still have many insurmountable defects and cannot fully meet the comprehensive requirements of bearings under actual working conditions. Alumina electrically insulated bearings prepared by spraying require significant modifications to the original bearing manufacturing process, which not only significantly increases manufacturing difficulty and production costs but also extends the procurement cycle. Furthermore, their structural characteristics make them unsuitable for complex working conditions such as vibration and shock, and repeated disassembly and assembly. The core weakness of hybrid ceramic bearings lies in the manufacturing and processing of ceramic rolling elements, especially ceramic cylindrical rollers, tapered rollers, and self-aligning rollers, which are extremely difficult to process. At the same time, these bearings are also unable to withstand vibration and shock, severely limiting their application scenarios. PVD physical vapor deposition (DLC) technology suffers from high costs and is currently mainly limited to the surface treatment of rolling elements. However, due to the complex structure and large size of the bearing outer and inner rings, it is difficult to ensure uniform film thickness when using this technology, leading to unstable anti-electro-erosion effects.

[0004] The market urgently needs a bearing surface anti-electro-erosion treatment technology that can effectively improve the bearing's resistance to electro-erosion without significantly changing the original bearing manufacturing process, and also has good technical effects on the bearing outer and inner rings, which are complex in structure and large in size. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a special surface treatment method for bearings to resist electrolytic corrosion and a bearing, comprising the following steps:

[0006] S1, The bearing to be treated undergoes special surface treatment and activation. The special surface treatment and activation steps are as follows:

[0007] S101, Ultrasonic-Electrochemical Composite Degreasing: First, an alkaline degreasing solution is prepared and a microcurrent is applied to the alkaline degreasing solution. The bearing is then immersed in the alkaline degreasing solution while ultrasonic vibration is applied for auxiliary treatment.

[0008] S102, Multi-stage activation: The bearing treated in step S101 is rinsed with deionized water, and then sprayed sequentially with ammonium citrate weak acid activation solution and suspension containing nano-cerium dioxide abrasive.

[0009] S2, Blackening treatment: The bearing treated in step S1 is degreased and cleaned again using the alkaline degreasing agent prepared in step S1. After cleaning, it is rinsed with deionized water until a complete water film is formed on the bearing surface. Then, the cleaned bearing is immersed in a dilute hydrochloric acid solution for acid washing and activation. After that, the acid-washed and activated bearing is rinsed with deionized water. Finally, the bearing that has undergone the above treatment steps is drained and then immersed in a blackening solution for further treatment.

[0010] S3, Micropore modification: Prepare a silane coupling agent for modifying micropores, immerse the bearing treated in step S2 into the silane coupling agent, and place the immersed bearing in an oven for curing.

[0011] S4, oil immersion treatment: Remove the bearing after step S3, rinse it with deionized water, and then use a special high-temperature oil immersion device to perform a special high-temperature oil immersion treatment on the outer ring, inner ring, and rolling elements of the bearing at a temperature of 130°C to 140°C for 10 to 20 minutes, according to the set requirements. During this period, use an agitator to stir the oil tank evenly to ensure the consistency of the oil immersion effect. After that, remove the bearing from the oil, let it stand above the oil tank to drain and cool naturally to room temperature.

[0012] S5, Controlled Polymer Sealing Treatment, involves immersing the oil-impregnated bearing in an aqueous polyurethane dispersion, lifting it out, and then curing it to form a transparent flexible polymer film.

[0013] S6. Before testing, the bearing surface is finished and homogenized. The bearing after step S5 is placed in a drum containing ceramic grinding blocks and rolled. During the rolling process, an ethanol aqueous solution is used as a lubricating and cooling medium.

[0014] S7, Perform volume resistivity testing on the treated bearing.

[0015] As a preferred embodiment, the degreasing solution in step S101 comprises: sodium phosphate 30g / L-50g / L, sodium carbonate 20g / L-30g / L, and nonionic surfactant 1g / L-2g / L. The ultrasonic-electrochemical composite degreasing treatment lasts for 10 to 15 minutes, the solution temperature is 60±2℃, and the applied current density is 2-5A / dm³. 2(Direct current, bearing as cathode), ultrasonic-assisted frequency: 40kHz, power density ≥0.5W / cm³ 2 .

[0016] As a preferred embodiment, in step S102, the concentration of the ammonium citrate weak acid activation solution is an 8-12% ammonium citrate aqueous solution, the temperature of the ammonium citrate weak acid activation solution is 40°C to 50°C, and the multi-stage activation spraying time is 3 minutes to 5 minutes.

[0017] As a preferred embodiment, in step S2, the temperature of the degreasing solution during the degreasing cleaning is 60±5 degrees Celsius, and the treatment time is approximately 15-30 minutes; the acid washing and activation step is as follows: immersion in a dilute hydrochloric acid solution with a temperature between 20-30 degrees Celsius and a volume ratio of 10%-15% for 1 to 3 minutes; the blackening solution includes a sodium hydroxide solution with a concentration of 600g / L-700g / L and a sodium nitrite solution with a concentration of 100g / L-150g / L, the working temperature of the blackening solution is 135 degrees Celsius to 145 degrees Celsius, and the blackening treatment time is 20 to 40 minutes.

[0018] As a preferred embodiment, the silane coupling agent is an aminosilane coupling agent ethanol solution with a concentration of 1% to 3%. The detailed steps of step S3 are as follows: immerse the bearing treated in step S2 into an aminosilane coupling agent ethanol solution with a concentration of 1% to 3%, soak for 3-5 minutes, take it out, and place it in an oven at 125°C to 135°C for curing for 15 minutes.

[0019] As a preferred embodiment, in step S4, the stirring rate during the oil immersion process is 600 r / min to 800 r / min, and the oil used in the oil immersion process is a Group II base oil or polyalphaolefin synthetic oil (PAO).

[0020] As a preferred embodiment, in step S5, the curing temperature is 80°C, the curing time is 10 minutes, and the thickness of the resulting transparent flexible polymer film is 2μm to 5μm.

[0021] As a preferred embodiment, in step S6, the concentration of the ethanol aqueous solution is 5%, and the low-speed rolling time is 30-40 minutes; the ceramic grinding block is a ZrO2 ceramic grinding ball with a diameter of φ3-5mm, and the low-speed rolling adopts an intermittent operation mode of "forward rotation-pause-reverse rotation", specifically: (1) forward rotation for 5 minutes at a frequency of 4Hz, (2) pause for 30 seconds, (3) reverse rotation for 5 minutes at a frequency of 4Hz, (4) pause for 30 seconds, which is one cycle, and the total processing time is 3-4 cycles.

[0022] As a preferred embodiment, in step S7, the reference temperature for the volume resistivity test is 23℃±0.5℃, and the relative humidity is not greater than 65%.

[0023] A bearing, prepared using the method described above.

[0024] The beneficial effects of this invention are:

[0025] To address the shortcomings of existing technologies, this invention provides a special surface treatment method for bearings to resist electro-erosion and a bearing itself. Through optimized structural design, this invention achieves the following technical effects:

[0026] Firstly, this invention rapidly and stably injects insulating oil into the pores of the microstructure of the black oxide layer of bearing parts, achieving better pore sealing. This results in bearing parts with special surface treatment having a resistivity that is more than 450 times higher than bearing parts with conventional black oxide treatment, thereby giving the bearings higher resistance to electro-erosion and significantly improving the overall resistance to electro-erosion of the bearings. Moreover, it does not require significant changes to the bearing production line, and it also has good technical effects on the outer and inner rings of bearings, which are complex in structure and large in size.

[0027] Secondly, by immersing the bearing components in oil at high temperature, the micropores of the black oxide layer of the bearing are efficiently sealed, which effectively improves the lubricant retention capacity. Combined with the protective effect of the outer transparent flexible polymer film, it ensures that the bearing retains oil during static storage and low-speed operation, and the film layer can be naturally broken through by the contact between the rolling elements and the raceway during normal operation of the bearing without affecting the lubrication effect.

[0028] Thirdly, this invention refines the microstructure of the bearing surface by using an aminosilane coupling agent ethanol solution, changing the inner wall of the micropores in the blackened layer from hydrophilic to oleophobic, and enhancing the binding force with lubricating oil molecules through chemical bonding. This treatment significantly reduces the lubricating oil loss rate of the bearing under static storage and low-speed operation conditions, achieving a dynamic balance between oil film retention and operational lubrication, and further increasing the durability of anti-electro-erosion performance. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of the present invention;

[0031] Figure 2 The image shows the surface micropores of the bearing component in Comparative Example 1.

[0032] Figure 3 This is a diagram of the micropores on the surface of the part in Example 2;

[0033] Figure 4 This is a schematic diagram of the oil immersion apparatus of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0035] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," and similar words used in the specification and claims of this patent application do not express a limitation of quantity, but rather indicate the presence of at least one; terms such as "comprising" or "including" indicate that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0036] This invention provides a special surface treatment method for bearings to resist electrolytic corrosion and a bearing, specifically including the following processing steps:

[0037] 1. Special Surface Treatment and Activation. This method goes beyond conventional cleaning, creating an optimal substrate for subsequent reactions. Activation can be performed using the following two methods:

[0038] (1) Ultrasonic-electrochemical composite degreasing: A microcurrent is applied to an alkaline degreasing solution, utilizing the electrochemical action of hydroxide ions to tear apart the oil film, achieving an ultra-clean effect. Degreasing solution composition: sodium phosphate 30-50 g / L, sodium carbonate 20-30 g / L, nonionic surfactant 1-2 g / L. Solution temperature: 60±2℃. Applied current density: 2-5 A / dm³ 2 (Direct current, workpiece is the cathode). Ultrasonic assisted frequency: 40kHz, power density ≥0.5W / cm² 2 Processing time: 10-15 minutes.

[0039] (2) Multi-stage activation: The process involves sequentially spraying the product with a weak acid activation solution of ammonium citrate followed by a suspension containing nano-cerium dioxide abrasive. The former gently removes the oxide film, while the latter creates numerous nanoscale pits through micro-abrasion, significantly increasing the specific surface area and resulting in a denser and more adhesive blackened layer. The activation solution used is an 8-12% ammonium citrate aqueous solution. The temperature is approximately 40-50℃. The process takes 3-5 minutes.

[0040] 2. Blackening treatment. Provides an ideal substrate for subsequent steps. Its porous microstructure can effectively adsorb and store the medium. (1) Use an alkaline degreasing agent for degreasing and cleaning. The temperature of the degreasing solution is 60±5℃; the treatment time is about 15-30 minutes. After cleaning, rinse with deionized water or pure water until a complete water film is formed on the surface of the workpiece to ensure that there is no oil residue. (2) In order to remove the extremely thin oxide layer and passivation film on the surface of the workpiece, activate the metal substrate, and ensure that the blackening reaction proceeds uniformly, acid pickling activation is required. Use a dilute hydrochloric acid solution with a volume ratio of 10-15% for immersion. The solution temperature is between 20-30℃, and the treatment time is about 1-3 minutes (until the surface is uniformly grayish-white, to avoid over-corrosion). After activation, rinse thoroughly with deionized water or pure water immediately. (3) Prepare a blackening solution using 600-700 g / L sodium hydroxide (NaOH) and 100-150 g / L sodium nitrite (NaNO2). Process flow: Immerse the pretreated and drained bearing workpieces in the blackening solution. Solution working temperature: 135-145℃, processing time: 20-40 minutes.

[0041] 3. Micropore modification. Immerse the workpiece in a 1-3% aminosilane coupling agent ethanol solution for 3-5 minutes, then remove it and cure it in an oven at 130℃ for 15 minutes. Then proceed with the oil impregnation step.

[0042] After modification with a silane coupling agent, the inner wall of the micropores in the blackened layer changes from hydrophilic to oleophobic, and the binding force with lubricating oil molecules is enhanced through chemical bonding. This treatment can significantly reduce the lubricating oil loss rate of bearings under static storage and low-speed operation conditions, improving oil retention capacity by more than 50%.

[0043] 4. Immerse in oil at high temperature and stir evenly.

[0044] After the blackened workpiece is removed, it is rinsed with flowing hot deionized water (>80℃). Next, the outer ring, inner ring, and rolling elements of the bearing are subjected to a special high-temperature oil immersion treatment at a temperature of 130-140℃ for 10-20 minutes, according to the set requirements, using a special high-temperature oil immersion device. During this process, the oil tank needs to be uniformly stirred with an agitator to ensure the consistency of the oil immersion effect. It should be noted that the high-temperature oil immersion process has very strict requirements on the oil immersion temperature and stirring process, specifically as follows: 1) The optimal oil immersion temperature needs to be controlled at 130-140℃, which is 30-40℃ lower than the conventional tempering temperature. Too low a temperature will result in insufficient oil immersion or require a long oil immersion treatment, increasing energy consumption. Too high a temperature may cause the workpiece to deform beyond expectations during the oil immersion process, similar to a secondary tempering process. The experiment revealed that without stirring, the resistivity increase factor of the specimens at different locations in the same experiment fluctuated significantly. After adding uniform stirring at 600-800 r / min, the fluctuation range of the resistivity increase factor of the specimens at different locations in the same experiment decreased by more than 30%, and the consistency was significantly improved. Afterward, the workpiece was removed from the oil and left to drain for 5-10 minutes above the oil tank. The drained workpiece was then placed in a clean environment and allowed to cool naturally to room temperature.

[0045] 5. Controlled polymerization sealing film treatment. An extremely thin sealing film is formed on the outermost layer to prevent oil leakage when not in operation, but this film layer can be broken during operation.

[0046] The oil-impregnated bearing is immersed in a specially formulated water-based polyurethane dispersion, then removed and cured at 80°C for 10 minutes to form a transparent, flexible polymer film approximately 2μm-5μm thick. This polymer film effectively prevents oil evaporation and loss at room temperature. When the bearing begins operation, the initial contact and micro-sliding between the rolling elements and raceways easily wears down this film, and the worn-off polymer fragments dissolve in the lubricating oil without any negative impact.

[0047] 6. Surface finishing and homogenization. Remove excess polymer film and floating oil from the surface to ensure bearing dimensional accuracy and smooth operation.

[0048] Place the bearing in a roller containing ceramic grinding blocks and roll it at low speed for 30-40 minutes. This process does not damage the substrate, but gently removes the polymer sealant and burrs on the raceway working surface, making the surface oil film uniform, while allowing the rolling elements to make a "pre-contact" with the raceway.

[0049] This horizontal vortex grinding mill employs frequency conversion control, allowing for stepless speed adjustment within the range of 2-10Hz (approximately 12-60rpm). The main body consists of φ3-5mm ZrO2 ceramic grinding balls with a smooth surface, high hardness, and wear resistance. φ1-2mm rhomboid polymer particles (such as POM) at a volume ratio of 10-20% can be used as an auxiliary agent for buffering, conduction, and grinding. A 5% ethanol aqueous solution is used as the lubricating and cooling medium to avoid introducing new contamination. The operation mode employs an intermittent "forward rotation-pause-reverse rotation" pattern. One cycle consists of 5 minutes of forward rotation at 4Hz, a 30-second pause, followed by 5 minutes of reverse rotation at 4Hz and a 30-second pause. Total processing time: 3-4 cycles, totaling 30-40 minutes.

[0050] 7. Volume resistivity detection

[0051] To verify the anti-electro-erosion effect of the present invention, the volume resistivity of the treated bearing was tested. The test method is as follows:

[0052] A four-probe resistivity / sheet resistance meter is used to measure the resistivity of the parts. Resistivity testing is affected by temperature, so it is necessary to maintain a stable temperature during the test. The recommended reference temperature is 23℃±0.5℃, and the relative humidity should not exceed 65%. Light also has a significant impact on resistivity testing, so the test should be carried out in low light or under a light shield.

[0053] Finally, all necessary inspections and tests are completed on the bearing parts, and the bearing is assembled into a finished product. After the bearing parts are assembled through special surface treatment, a brand-new anti-electro-erosion bearing is formed.

[0054] To more clearly describe the special surface treatment method for resisting electro-erosion of the bearing and the bearing itself, in conjunction with the attached... Figure 1 - Appendix Figure 4 This embodiment is described as follows:

[0055] Example 1 (using Group II base oils and undergoing sealing treatment):

[0056] This embodiment includes the following steps:

[0057] S1, The bearing to be treated undergoes special surface treatment and activation. The special surface treatment and activation steps are as follows:

[0058] S101, Ultrasonic-Electrochemical Composite Degreasing: First, an alkaline degreasing solution is prepared, and a microcurrent is applied to the solution. The bearing is then immersed in the solution while ultrasonic vibration is applied as an auxiliary treatment. The degreasing solution contains: 40 g / L sodium phosphate, 23 g / L sodium carbonate, and 2 g / L nonionic surfactant. The ultrasonic-electrochemical composite degreasing treatment lasts for 15 minutes, with the solution temperature maintained at 60°C and the applied current density at 5 A / dm³.2 (Direct current, bearing as cathode), ultrasonic-assisted frequency: 40kHz, power density ≥0.5W / cm³ 2 ;

[0059] S102, Multi-stage activation: The bearing treated in step S101 is rinsed with deionized water, and then sprayed sequentially with ammonium citrate weak acid activation solution and a suspension containing nano-cerium dioxide abrasive; wherein the concentration of ammonium citrate weak acid activation solution is 12% ammonium citrate aqueous solution, the temperature of the ammonium citrate weak acid activation solution is 50℃, and the multi-stage activation spraying time is 5 minutes.

[0060] S2, Blackening treatment: The bearing treated in step S1 is degreased and cleaned again using the alkaline degreasing agent prepared in step S1. After cleaning, it is rinsed with deionized water until a complete water film is formed on the bearing surface. Then, the cleaned bearing is immersed in a dilute hydrochloric acid solution for acid washing and activation. After that, the acid-washed and activated bearing is rinsed with deionized water. Finally, the bearing that has undergone the above treatment steps is drained and then immersed in a blackening solution for further treatment.

[0061] S3, Micropore modification: Prepare a silane coupling agent for modifying micropores, immerse the bearing treated in step S2 into the silane coupling agent, and place the immersed bearing in an oven for curing.

[0062] S4, Oil Immersion Treatment: Remove the bearing treated in step S3 and rinse it with flowing hot deionized water (>80℃) for 5 minutes. Then, use a special high-temperature oil immersion device to perform a special high-temperature oil immersion treatment on the outer ring, inner ring, and rolling elements of the bearing at a temperature of 135℃ for 20 minutes, according to the set requirements. During this period, use a stirrer to evenly stir the oil bath to ensure the consistency of the oil immersion effect. Afterward, remove the bearing from the oil and let it stand above the oil tank to drain and cool naturally to room temperature. The special high-temperature oil immersion device includes an oil immersion tank, with heaters for heating the oil bath and temperature controllers for monitoring the oil bath temperature at both ends. Its specific structure is shown in the attached figure. Figure 4 As shown;

[0063] S5, Controlled Polymer Sealing Treatment, involves immersing the oil-impregnated bearing in an aqueous polyurethane dispersion, lifting it out, and then curing it to form a transparent flexible polymer film. The curing temperature is 80℃ and the curing time is 10 minutes.

[0064] S6. Before testing, the bearing surface is finished and homogenized. The bearing after step S5 is placed in a drum containing ceramic grinding blocks and rolled. During the rolling process, an ethanol aqueous solution is used as a lubricating and cooling medium.

[0065] S7, Perform volume resistivity testing on the treated bearing.

[0066] In this embodiment, in step S2, the temperature of the degreasing solution during the degreasing cleaning is 65 degrees Celsius, and the treatment time is 30 minutes; the acid washing and activation step is: immersion in a dilute hydrochloric acid solution at 30 degrees Celsius and a volume ratio of 15% for 2 minutes; the blackening solution includes a sodium hydroxide solution with a concentration of 700 g / L and a sodium nitrite solution with a concentration of 150 g / L, the working temperature of the blackening solution is 140 degrees Celsius, and the blackening treatment time is 30 minutes.

[0067] In this embodiment, the detailed steps of step S3 are as follows: immerse the bearing treated in step S2 into a 2% aminosilane coupling agent ethanol solution, soak for 3 minutes, then remove it and place it in an oven at 135°C for curing for 15 minutes.

[0068] In this embodiment, in step S4, the stirring rate during the oil immersion process is 800 r / min, and the oil used in the oil immersion process is a Group II base oil.

[0069] In this embodiment, in step S6, the concentration of the ethanol aqueous solution is 5%, the ceramic grinding block is a ZrO2 ceramic grinding ball with a diameter of 3-5mm, and the low-speed rolling adopts an intermittent operation mode of "forward rotation-pause-reverse rotation", specifically: (1) forward rotation for 5 minutes at a frequency of 4Hz, (2) pause for 30 seconds, (3) reverse rotation for 5 minutes at a frequency of 4Hz, (4) pause for 30 seconds. This is one cycle, and the total processing time is 4 cycles.

[0070] In this embodiment, in step S7, the volume resistivity test uses a four-probe resistivity / sheet resistance tester to measure the resistivity of the component. Resistivity testing is affected by temperature, therefore it is necessary to maintain temperature stability during the test. The recommended reference temperature is 23℃±0.5℃, and the relative humidity should not exceed 65%. Furthermore, light exposure has a significant impact on resistivity testing, requiring the test to be conducted in low light conditions or under a light shield.

[0071] Example 2 (using polyalphaolefin synthetic oil and sealing treatment):

[0072] The difference between this embodiment and Embodiment 1 is that in step S4, the oil used in the oil immersion process is a Group IV base oil, while in this embodiment, polyalphaolefin synthetic oil (PAO) is used.

[0073] Example 3 (using only Group II base oils):

[0074] The difference between this embodiment and Embodiment 1 is that step S5 is omitted and the bearing parts are not sealed.

[0075] Example 4 (using only polyalphaolefin synthetic oil):

[0076] The difference between this embodiment and embodiment two is that step S5 is omitted and the bearing parts are not sealed.

[0077] Comparative Example 1 (blackened only):

[0078] 1. The bearing to be treated undergoes special surface treatment and activation. The special surface treatment and activation steps are as follows:

[0079] S101, Ultrasonic-Electrochemical Composite Degreasing: First, an alkaline degreasing solution is prepared, and a microcurrent is applied to the solution. The bearing is then immersed in the solution while ultrasonic vibration is applied as an auxiliary treatment. The degreasing solution contains: 40 g / L sodium phosphate, 23 g / L sodium carbonate, and 2 g / L nonionic surfactant. The ultrasonic-electrochemical composite degreasing treatment lasts for 15 minutes, with the solution temperature maintained at 60°C and the applied current density at 5 A / dm³. 2 (Direct current, bearing as cathode), ultrasonic-assisted frequency: 40kHz, power density ≥0.5W / cm³ 2 ;

[0080] S102, Multi-stage activation: The bearing treated in step S101 is rinsed with deionized water, and then sprayed sequentially with ammonium citrate weak acid activation solution and a suspension containing nano-cerium dioxide abrasive; wherein the concentration of ammonium citrate weak acid activation solution is 12% ammonium citrate aqueous solution, the temperature of the ammonium citrate weak acid activation solution is 50℃, and the multi-stage activation spraying time is 5 minutes.

[0081] S2, Blackening treatment: The bearing treated in step S1 is degreased and cleaned again using the alkaline degreasing agent prepared in step S1. After cleaning, it is rinsed with deionized water until a complete water film is formed on the bearing surface. Then, the cleaned bearing is immersed in a dilute hydrochloric acid solution for acid washing and activation. After that, the acid-washed and activated bearing is rinsed with deionized water. Finally, the bearing that has undergone the above treatment steps is drained and immersed in a blackening solution for treatment to obtain Comparative Example 1.

[0082] Data Comparison:

[0083] Examples 1 to 4 and Comparative Example 1 were tested on various components of the prepared bearing, including rollers, inner ring, and outer ring, according to the testing method. The following data were obtained: Table 1 shows the resistivity data of the rollers after different treatment methods; Table 2 shows the resistivity data of the inner ring after different treatment methods; Table 3 shows the resistivity data of the outer ring after different treatment methods. The data in the "Untreated" column of Tables 1 to 3 represents Comparative Example 1 (only blackening treatment was performed). "Using Group II base oil but without sealing film" represents Example 3; "Using Group II base oil with controlled sealing film" represents Example 1; "Using polyalphaolefin synthetic oil but without sealing film treatment" represents Example 4; and "Using polyalphaolefin synthetic oil with controlled sealing film" represents Example 2.

[0084]

[0085]

[0086]

[0087] By conducting volume resistivity tests on the rollers, inner ring, and outer ring of the bearings prepared in Examples 1 to 4 and Comparative Example 1, and comparing the data with those of the untreated bearings, the significant performance improvement brought about by the present invention can be clearly seen. The test results show that the volume resistivity of each component of the bearing treated with the surface treatment method of the present invention has achieved a breakthrough increase compared to bearings treated with conventional black anodizing. The resistivity increase of the rollers can reach more than 1400 times, and the resistivity increases of the inner and outer rings both exceed 500 times, effectively verifying the core advantage of the present invention in improving the insulation performance of bearings. Comparing Examples 1 and 2, it can be seen that when polyalphaolefin (PAO) is used in the oil impregnation step, the resistivity values ​​of each bearing component are higher and the stability is better. The resistivity fluctuation range of different locations in the same batch of products is further reduced compared to when Group II base oil is used.

[0088] Compared with existing technologies such as alumina electrically insulated bearings, hybrid ceramic bearings, and PVD physical vapor deposition (DLC) bearings, the advantages of this invention are reflected in several dimensions. First, this invention does not require changes to the original manufacturing process and structural design of the bearing, avoiding the increased manufacturing difficulty, soaring costs, and extended procurement cycles associated with spraying processes. It also eliminates the need for complexly processed ceramic rolling elements, significantly reducing production and application costs. Furthermore, it is compatible with complex operating conditions such as vibration and shock, and repeated disassembly and assembly, making it more widely applicable. Second, addressing the issue of uniform film thickness between the outer and inner rings of the bearing, which is difficult to solve with PVD physical vapor deposition (DLC) technology, this invention achieves a high degree of uniformity in the surface treatment of all bearing components through the synergistic effect of multiple steps, including special surface treatment and activation, micropore modification, and controllable polymerization sealing. Test data shows that the resistivity fluctuation of each component is controlled at a low level, far exceeding the processing accuracy of existing technologies. Furthermore, this invention achieves efficient sealing of the micropores in the black oxide layer of the bearing through high-temperature oil immersion, effectively improving the lubricant retention capacity. Combined with the protective effect of the outer transparent flexible polymer film, it ensures oil retention in the bearing during static storage and low-speed operation, while also allowing the film to be naturally broken through through the contact between the rolling elements and the raceway during normal bearing operation, without affecting the lubrication effect. This dynamic protection mechanism is difficult to achieve with existing technologies.

[0089] In summary, this invention, through collaborative innovation involving multi-step refined processing, not only solves numerous pain points in existing anti-electro-erosion bearings, such as high manufacturing difficulty, high cost, poor adaptability to operating conditions, and insufficient film thickness uniformity, but also achieves a leapfrog improvement in the bearing's anti-electro-erosion performance. The bearings prepared using this invention, with their extremely high volume resistivity, can effectively cut off the shaft current loop, fundamentally inhibiting electrochemical corrosion and significantly extending the bearing's service life under high-reliability conditions such as wind turbine generator sets. Furthermore, this invention boasts strong process compatibility and high operational controllability, requiring no special equipment and easily enabling industrial-scale mass production. Compared to existing technologies, it possesses irreplaceable advantages in terms of economy, practicality, and performance stability, providing a more efficient, reliable, and cost-effective solution for bearing anti-electro-erosion technology.

[0090] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A special surface treatment method for bearings to resist electrolytic corrosion, characterized in that, Includes the following steps: S1, The bearing to be treated undergoes special surface treatment and activation. The special surface treatment and activation steps are as follows: S101, Ultrasonic-Electrochemical Composite Degreasing: First, an alkaline degreasing solution is prepared and a microcurrent is applied to the alkaline degreasing solution. The bearing is then immersed in the alkaline degreasing solution while ultrasonic vibration is applied for auxiliary treatment. S102, Multi-stage activation: The bearing treated in step S101 is rinsed with deionized water, and then sprayed sequentially with ammonium citrate weak acid activation solution and suspension containing nano-cerium dioxide abrasive. S2, Blackening Treatment: The bearing treated in step S1 is degreased and cleaned again using the alkaline degreasing agent prepared in step S1. After cleaning, it is rinsed with deionized water until a complete water film is formed on the bearing surface. Then, the cleaned bearing is immersed in a dilute hydrochloric acid solution for acid washing and activation. After that, the acid-washed and activated bearing is rinsed with deionized water. Finally, after draining the water from the bearing that has undergone the above treatment steps, it is immersed in a blackening solution for treatment. The blackening solution includes a sodium hydroxide solution with a concentration of 600g / L-700g / L and a sodium nitrite solution with a concentration of 100g / L-150g / L. The working temperature of the blackening solution is 135℃ to 145℃, and the blackening treatment time is 20 minutes to 40 minutes. S3, Micropore modification: Prepare a silane coupling agent for modifying micropores. Immerse the bearing treated in step S2 into the silane coupling agent and place the immersed bearing in an oven for curing. The silane coupling agent is a 1% to 3% aminosilane coupling agent ethanol solution. The detailed steps of immersion and curing are as follows: Immerse the bearing treated in step S2 into a 1% to 3% aminosilane coupling agent ethanol solution for 3-5 minutes, then remove it and place it in an oven at 125°C to 135°C for curing for 15 minutes. S4, Oil Immersion Treatment: Remove the bearing treated in step S3, rinse it with deionized water, and then use a special high-temperature oil immersion device to treat the outer ring, inner ring, and rolling elements of the bearing at a temperature of 130°C to 140°C for 10 to 20 minutes according to the set requirements. During the treatment, a stirrer is used to evenly stir the oil tank to ensure the consistency of the oil immersion effect. Afterwards, remove the bearing from the oil, let it stand above the oil tank to drain and cool naturally to room temperature. The stirring rate during the oil immersion process is 600 r / min to 800 r / min, and the oil used in the oil immersion process is a Group II base oil or a polyalphaolefin synthetic oil. S5, Controlled Polymer Sealing Treatment, involves immersing the oil-impregnated bearing in an aqueous polyurethane dispersion, lifting it out, and then curing it to form a transparent flexible polymer film. S6. Before testing, the bearing surface is finished and homogenized. The bearing after step S5 is placed in a drum containing ceramic grinding blocks and rolled. During the rolling process, an ethanol aqueous solution is used as a lubricating and cooling medium. S7, Perform volume resistivity testing on the treated bearing.

2. The special surface treatment method for bearing anti-electro-erosion according to claim 1, characterized in that, The degreasing solution in step S101 includes: sodium phosphate 30g / L-50g / L, sodium carbonate 20g / L-30g / L, and nonionic surfactant 1g / L-2g / L. The ultrasonic-electrochemical composite degreasing treatment takes 10 to 15 minutes. During the treatment, the solution temperature is 60±2℃, the applied current density is 2A / dm²-5A / dm², the ultrasonic auxiliary frequency is 40kHz, and the power density is ≥0.5W / cm².

3. The special surface treatment method for bearing anti-electro-erosion according to claim 1, characterized in that, In step S102, the ammonium citrate weak acid activation solution is an aqueous solution of ammonium citrate with a concentration of 8%-12%, the temperature of the ammonium citrate weak acid activation solution is 40℃ to 50℃, and the multi-stage activation spraying time is 3 minutes to 5 minutes.

4. The special surface treatment method for bearing anti-electro-erosion according to claim 1, characterized in that, In step S2, the temperature of the degreasing solution during the degreasing cleaning is 60±5℃, and the treatment time is 15-30 minutes; the acid washing and activation step is: immersing in a dilute hydrochloric acid solution with a temperature between 20-30℃ and a volume ratio of 10%-15% for 1 to 3 minutes.

5. The special surface treatment method for bearing anti-electro-erosion according to claim 1, characterized in that, In step S5, the curing temperature is 80°C, the curing time is 10 minutes, and the thickness of the resulting transparent flexible polymer film is 2μm to 5μm.

6. The special surface treatment method for bearing anti-electro-erosion according to claim 1, characterized in that, In step S6, the concentration of the ethanol aqueous solution is 5%, and the low-speed rolling time is 30-40 minutes; the ceramic grinding block is a ZrO2 ceramic grinding ball with a diameter of φ3-5mm, and the low-speed rolling adopts an intermittent operation mode of "forward rotation-pause-reverse rotation", specifically: (1) forward rotation for 5 minutes at a frequency of 4Hz, (2) pause for 30 seconds, (3) reverse rotation for 5 minutes at a frequency of 4Hz, (4) pause for 30 seconds, which is one cycle, and the total processing time is 3-4 cycles.

7. The special surface treatment method for bearing anti-electro-erosion according to claim 1, characterized in that, In step S7, the reference temperature for the volume resistivity test is 23℃±0.5℃, and the relative humidity is not greater than 65%.

8. A bearing, characterized in that, Prepared by any one of the methods of claims 1 to 7.

Images