Wind power bearing lubricating grease composition with excellent fretting wear resistance

Abstract

The invention provides a wind power bearing lubricating grease composition with excellent fretting wear resistance. The wind power bearing lubricating grease composition comprises the following components by weight: 5-8 parts of an anti-wear reagent at extreme pressure; 0.05 to 0.2 part of a metal deactivator; 1-2 parts of an antioxidant; 9-12 parts of a composite lithium-based thickening agent; 5 to 15 parts of ester oil; 5-15 parts of mineral oil; and the balance of PAO base oil. The anti-wear reagent at extreme pressure comprises one or more of tricresyl phosphate, ammonium thiophosphate, sulfurized isobutylene, amino thioester, molybdenum dialkyl dithiophosphate and graphene oxide solvent-free nanofluid. The lubricating grease composition shows extremely excellent tribological performance, and the extreme pressure anti-wear performance and the fretting wear resistance of the lubricating grease composition are superior to those of domestic wind power lubricating grease with the same consistency level and are also superior to those of foreign brands with the same consistency level. The method is suitable for the requirement of long-term use of the wind power generation main bearing on fretting wear performance, and the advantage is mainly characterized in that the wear scar diameter is reduced and the wear is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power bearing greases, and in particular relates to a wind power bearing grease composition with excellent anti-fretting wear performance. Background Art

[0002] Wind energy is one of the most abundant renewable energy sources in the world. Data from the World Wind Energy Association shows that as of June 2024, the cumulative global wind power installed capacity was 1.09 million MW, with China accounting for 45.6%, followed closely by Europe and the United States. By the end of 2024, wind power will meet approximately 11% of the global electricity demand. As of June 2024, China's total wind power installed capacity was 500,000 MW, and wind power is expected to cover 15 - 20% of the domestic electricity demand, far higher than the global average level (11%). The newly installed capacity is approximately 5 times the sum of other regions in the world.

[0003] For every 1 GW of wind power installed capacity, approximately 100 tons of wind power grease are required. In 2023, the market size of wind power grease in China reached approximately 4.5 billion yuan, a year-on-year increase of 8.5%. However, the limited supply side is an issue that cannot be ignored.

[0004] Generally, a wind turbine includes blades (rotor blades), a tower (support column), and a nacelle (the main body that generates electricity). The grease composition is used in the main shaft support bearings that rotate the blades under the action of wind, the blade bearings used in the pitch turntables of the blades, the yaw rotation bearings used in the yaw turntables of the nacelle, etc. The main technical difficulties lie in wide temperature range stability, anti-fretting wear, long life and durability, and bearing micro-spalling wear. Summary of the Invention

[0005] In view of this, the present invention aims to provide a wind power bearing grease composition with excellent anti-fretting wear performance to solve at least one of the technical problems in the background art.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows: A wind power bearing grease composition with excellent anti-fretting wear performance comprises the following components by weight: Extreme pressure and anti-wear agent: 5 - 8 parts; Metal deactivator: 0.05 - 0.2 parts; Antioxidant: 1 - 2 parts; Complex lithium-based thickener: 9 - 12 parts; Ester oil: 5 - 15 parts; Mineral oil: 5 - 15 parts; Base oil: the balance; The extreme pressure and anti-wear agent includes one or more of tricresyl phosphate, ammonium salt of thiophosphate, sulfurized isobutene, amino thioester, molybdenum dialkyldithiophosphate, and graphene oxide solvent-free nanofluid.

[0007] Further, the complex lithium-based thickener includes one or more of dodecahydroxystearic acid, boric acid, azelaic acid, and sebacic acid.

[0008] Further, the complex lithium-based thickener is dodecahydroxystearic acid, boric acid, and azelaic acid.

[0009] Further, the extreme pressure and anti-wear agent is tricresyl phosphate, ammonium salt of thiophosphate, sulfurized isobutene, amino thioester, molybdenum dialkyldithiophosphate, and graphene oxide solvent-free nanofluid.

[0010] Further, the preparation method of the graphene oxide solvent-free nanofluid includes the following steps: S1: Prepare a premixed solution; S2: Add a graphene oxide dispersion to the premixed solution prepared in step S1, and stir to obtain a mixed solution; S3: Subject the mixed solution in step S2 to primary rotary evaporation, dialysis, secondary rotary evaporation, and vacuum drying to obtain the graphene oxide solvent-free nanofluid.

[0011] Further, preparing the premixed solution in step S1 includes mixing deionized water and methanol, heating, and rapidly stirring until the solution is fully mixed; Subsequently, add a certain amount of polyetheramine, and apply a small amount of polyetheramine to the flask mouth to enhance airtightness and avoid contamination. Finally, add a certain amount of silane coupling agent and continue stirring for 24 - 48 hours to obtain the premixed solution; Preferably, the silane coupling agent is KH560.

[0012] Further, in step S2, place deionized water in a water bath, and at the same time add an ice pack to cool down. Slowly pour the graphene oxide dispersion into the premixed solution prepared in step S1, and stir with a magnetic stirrer at a stable speed to keep the temperature stable. The stirring time is 24 - 48 hours.

[0013] Further, the temperature of the primary rotary evaporation in step S3 is 30 - 70 °C, and stir at 10 - 100 r; The dialysis in step S3 includes pouring the liquid after rotary evaporation into a dialysis bag, and suspending it in a beaker filled with a large amount of deionized water. Subsequently, slowly stir and dialyze for 48 - 72 hours, and change the dialysis water every 4 - 12 h; The cut-off molecular weight of the dialysis bag is 1000 - 7000 Da: The temperature of the secondary rotary evaporation in step S3 is 20 - 40 °C, and perform rotary evaporation at 100 - 200 r.

[0014] Further, the antioxidant includes one or more of ditertiary butyl p-cresol, ditertiary butyl mixed phenol, dinonyl diphenylamine, and ditertiary butyl-4-hydroxyphenyl acrylate.

[0015] Further, the metal deactivator is a benzotriazole derivative; The antioxidant and anti-corrosion agent is zinc salt of sulfur-phosphorus butyl octyl; The base oil is PAO40 and PAO100.

[0016] Compared with the prior art, the wind power bearing grease composition with excellent anti-fretting wear performance of the present invention has the following advantages: The self-made extreme pressure anti-wear agent of the present application can form a synergistic effect with molybdenum dialkyldithiophosphate (MoDTP) in the formulation system, greatly reducing the wear of the grease during the fretting wear and anti-wear performance tests. Specifically, the wear scar diameter is smaller and the shape is complete. The self-made additive is a nanofluid composed of a core, a neck layer, and a crown layer. The core is graphene oxide nanosheets (GO), the neck layer is a small molecule KH560 with a connecting function, and the crown layer is a polyetheramine with a low degree of polymerization. It can be uniformly dispersed in the grease without settling over time while retaining the characteristics of the nanomaterials themselves. It has little impact on other properties of the complex lithium base grease, and the grease still has excellent high temperature resistance, colloidal stability, etc.

[0017] The grease composition of the present application exhibits extremely excellent tribological properties. Its extreme pressure anti-wear performance and anti-fretting wear ability are superior to domestic wind power greases in the same special wind power positions, and also superior to greases of foreign brands in the same special wind power positions. It meets the requirements for fretting wear performance during long-term use of the main shaft yaw and pitch bearings of wind turbines. This advantage is mainly manifested in the reduction of the wear scar diameter and wear. Description of the Drawings

[0018] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is the surface wear trace diagram of the fretting wear steel ball friction pair described in Comparative Example 1 of the present invention; Figure 2 It is the surface wear trace diagram of the fretting wear steel ball friction pair described in Comparative Example 2 of the present invention; Figure 3 It is the surface wear trace diagram of the fretting wear steel ball friction pair described in Comparative Example 2 of the present invention; Figure 4 It is the surface wear trace diagram of the fretting wear steel ball friction pair described in Example 1 of the present invention; Figure 5The surface wear trace diagram of the fretting wear steel ball friction pair described in Embodiment 2 of the present invention; Figure 6 The surface wear trace diagram of the fretting wear steel ball friction pair described in Embodiment 3 of the present invention; Figure 7 The surface wear trace diagram of the fretting wear steel ball friction pair described in Embodiment 4 of the present invention. Detailed implementation manners

[0019] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0020] The present invention will be described in detail below with reference to the drawings and in combination with embodiments.

[0021] In the following examples, amine salt of acidic phosphate is purchased from Shenyang Hualun Lubricant Additive Co., Ltd., code number T308; triphenyl thionophosphate is purchased from Jinzhou Shengda Chemical Co., Ltd., code number T309. Triphenyl thionophosphate (imported product) is purchased from BASF, code number IR211. Tricresyl phosphate is purchased from Zibo Huihua Petroleum Additive Co., Ltd., code number T306. Aminothiocarbamate is purchased from Shenyang Hualun Lubricant Additive Co., Ltd., code number T323. Dialkyldithiophosphate (imported product) is purchased from BASF, code number IR353. Molybdenum dialkyldithiophosphate is purchased from Vanderbilt, code number Molyvan L; N,N-dibutylaminomethylbenzotriazole is purchased from Jinzhou Xinxing Petroleum Additive Co., Ltd., code number T551; benzotriazole derivative is purchased from Changsha Wangcheng Petrochemical Co., Ltd., code number T553. 2,6-Di-tert-butyl-p-cresol is purchased from Jinzhou Xinxing Petroleum Additive Co., Ltd., code number T501; octyl / butyldiphenylamine is purchased from Jinzhou Xinxing Petroleum Additive Co., Ltd., code number T557. Fatty acid pentaerythritol ester is purchased from Croda, code number 3970; 150BS base oil is purchased from IRPC in Thailand; PAO40 and PAO100 base oils are purchased from Mobil.

[0022] Preparation process of self-made extreme pressure and anti-wear agent: 1. Pretreatment and mixing Add a certain amount of deionized water and methanol into a single-neck flask, heat up, and stir rapidly until the solution is fully mixed. Subsequently, add a certain amount of polyetheramine, and apply a small amount of polyetheramine to the flask mouth to enhance airtightness and avoid contamination. Finally, add a certain amount of KH560 and continue stirring for 24 - 48 hours to obtain a premixed solution.

[0023] 2. Preparation of graphene oxide dispersion Place a certain amount of deionized water in a water bath and add an ice pack to cool it down. Slowly pour the graphene oxide dispersion into the premixed solution and stir it with a magnetic stirrer at a stable speed. Keep the temperature stable and stir for 24 - 48 hours.

[0024] 3. Preliminary concentration by rotary evaporation Transfer the above - mentioned mixed liquid to a rotary evaporator, heat it at 30 - 70 °C, stir at 10 - 100 r, and start rotary evaporation to prepare for subsequent operations.

[0025] 4. Dialysis Use a dialysis bag with a molecular weight cut - off of 1000 - 7000 Da, place it in boiling pure water for treatment to remove surface impurities and ensure cleanliness. Pour the liquid after rotary evaporation into the dialysis bag and suspend it in a beaker filled with a large amount of deionized water, then slowly stir and dialyze for 48 - 72 hours, changing the dialysis water every 4 - 12 hours.

[0026] 5. Concentration by rotary evaporation Transfer the liquid after dialysis to a rotary evaporation flask and perform rotary evaporation at 20 - 40 °C and 100 - 200 r. According to the vacuum degree and liquid characteristics, pay attention to preventing bumping.

[0027] 6. Vacuum drying Transfer the concentrated liquid after rotary evaporation to a vacuum drying oven and dry it under a conventional vacuum degree. After ensuring that the residual moisture in the lower layer is completely evaporated, adjust to the ultimate vacuum degree of the vacuum drying oven and continue drying to finally obtain a solvent - free nanofluid of graphene oxide, coded as GO - NFs.

[0028] Comparative example 1: T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; T553, 0.5%; T501, 0.5%; T557, 0.5%; thickening agent 15%, ester oil (3970) 20%; mineral oil (150BS), 20%; PAO (PAO100 and PAO40) for the balance.

[0029] Comparative example 2: T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; GO - NFs, 1%; T553, 0.5%; T501, 0.5%; T557, 0.5%; thickening agent 15%, ester oil (3970) 20%; mineral oil (150BS), 20%; PAO (PAO100 and PAO40) for the balance.

[0030] Comparison column 3: T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; Molyvan L, 1%; T553, 0.5%; T501, 0.5%; T557, 0.5%; Thickener 15%, Ester oil (3970) 20%; Mineral oil (150BS), 20%; PAO (PAO100 and PAO40) remainder.

[0031] Example 1 T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; Molyvan L, 0.3%; GO-NFs, 0.7%; T553, 0.5%; T501, 0.5%; T557, 0.5%; Thickener 15%, Ester oil (3970) 20%; Mineral oil (150BS), 20%; PAO (PAO100 and PAO40) remainder.

[0032] Example 2 T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; Molyvan L, 0.7%; GO-NFs, 0.3%; T553, 0.5%; T501, 0.5%; T557, 0.5%; Thickener 15%, Ester oil (3970) 20%; Mineral oil (150BS), 20%; PAO (PAO100 and PAO40) remainder.

[0033] Example 3 T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; Molyvan L, 0.5%; GO-NFs, 0.5%; T553, 0.5%; T501, 0.5%; T557, 0.5%; Thickener 15%, Ester oil (3970) 20%; Mineral oil (150BS), 20%; PAO (PAO100 and PAO40) remainder.

[0034] Example 4 T308, 0.1%; T309, 2%; T306, 2%; IR211, 0.5%; IR353, 0.5%; T323, 0.5%; Molyvan L, 1%; GO-NFs, 1%; T553, 0.5%; T501, 0.5%; T557, 0.5%; Thickening agent 15%, Ester oil (3970) 20%; Mineral oil (150BS), 20%; PAO (PAO100 and PAO40) the balance.

[0035] The examples and comparative examples are all greases with a consistency grade of No. 1.5.

[0036] The anti-wear performance and anti-fretting wear performance of the examples and comparative examples were investigated.

[0037] For the anti-wear performance, the SH / T 0204 method was used. Under the conditions of 392 N, 60 min, 75 °C, and 1200 r / min, the smaller the wear scar diameter, the stronger the anti-wear ability of the grease.

[0038] For the anti-fretting wear, the ASTM D7594 method was used. Under the conditions of 100 N, 4 h, 50 °C, 0.3 mm, and 50 Hz, the smaller and more complete the wear track of the steel ball friction pair, the stronger the anti-fretting ability of the grease. The grease composition uses a three-component complex lithium (dodecahydroxystearic acid, boric acid, azelaic acid) as a thickener, and is compounded with a variety of extreme pressure and anti-wear agents (tricresyl phosphate, ammonium thiophosphate, sulfurized isobutene, amino thioester, molybdenum sulfide oxide dibutyldithiophosphate, self-made extreme pressure and anti-wear agent (graphene oxide solvent-free nanofluid (GO-NFs))), antioxidants (2,6-di-tert-butyl-p-cresol, mixed di-tert-butylphenol, dinonyl diphenylamine, di-tert-butyl-4-hydroxy phenyl acrylate), metal deactivators (benzotriazole derivatives) and anti-oxidation and anti-corrosion agents (zinc salt of thiophosphoric acid dioctyl octyl ester). Among them, the self-made extreme pressure and anti-wear agent can form a synergistic effect with molybdenum sulfide oxide dibutyldithiophosphate (MoDTP) in the formulation system, greatly reducing the wear of the grease during the fretting wear and anti-wear performance tests. The specific performance is that the wear scar diameter is smaller and the shape is complete. The self-made additive is a nanofluid composed of a core, a neck layer and a crown layer. The core is graphene oxide nanosheets (GO), the neck layer is a small molecule KH560 with a connecting function, and the crown layer is a polymer substance polyetheramine with a low degree of polymerization. It can be evenly dispersed in the grease and will not settle over time while retaining the characteristics of the nanomaterials themselves. It has little effect on other properties of the complex lithium base grease, and the grease still has excellent high temperature resistance, colloidal stability, etc. The grease composition exhibits extremely excellent tribological properties, and its extreme pressure and anti-wear performance and anti-fretting wear ability are superior to domestic wind power greases of the same consistency level and also superior to greases of the same consistency level of foreign brands. It meets the requirements for fretting wear performance during long-term use of wind power main bearings. This advantage is mainly manifested in the reduction of the wear scar diameter and abrasive wear.

[0039] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wind turbine bearing grease composition with excellent anti-fretting wear performance, characterized in that: The components by weight are as follows: 5-8 parts of extreme pressure anti-wear agent; Metal deactivator 0.05-0.2 parts; 1-2 parts of antioxidant; 9-12 parts of composite lithium-based thickener; 5-15 parts of ester oil; Mineral oil 5-15 parts; Base oil balance; The extreme pressure anti-wear agent includes one or more of tricresyl phosphate, ammonium thiophosphate, sulfided isobutylene, aminothioester, dialkyl molybdenum dithiophosphate, and graphene oxide solvent-free nanofluid.

2. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 1, characterized in that: The complex lithium-based thickener includes one or more of dodecyl hydroxystearic acid, boric acid, azelaic acid and sebacic acid.

3. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 1, characterized in that: The composite lithium-based thickener is dodecyl hydroxystearic acid, boric acid and azelaic acid.

4. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 1, characterized in that: The extreme pressure anti-wear agent is tricresol phosphate, ammonium thiophosphate, sulfided isobutylene, aminothioester, dialkyl molybdenum dithiophosphate and graphene oxide solvent-free nanofluid.

5. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 1, characterized in that: The method for preparing a graphene oxide solvent-free nanofluid comprises the following steps: S1: prepare premix solution; S2: adding the graphene oxide dispersion to the premixed solution prepared in step S1, and stirring to obtain a mixed solution; S3: The mixed solution in step S2 is subjected to primary rotary evaporation, dialysis, secondary rotary evaporation, and vacuum drying to obtain a graphene oxide solvent-free nanofluid.

6. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 5, characterized in that: The step S1 of preparing the premixed solution includes mixing deionized water and methanol, heating, and rapidly stirring until the solution is fully mixed; Then, a certain amount of polyetheramine is added, and a small amount of polyetheramine is applied to the mouth of the flask to enhance air tightness and avoid contamination. Finally, a certain amount of silane coupling agent is added, and stirring is continued for 24-48 hours to obtain a premixed solution; Preferably, the silane coupling agent is KH560.

7. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 5, characterized in that: In step S2, deionized water is placed in a water bath and ice bags are added to cool it down. The graphene oxide dispersion is slowly poured into the premixed solution prepared in step S1, and stirred at a stable speed with a magnetic stirrer to keep the temperature stable for 24-48 hours.

8. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 5, characterized in that: The temperature of the initial rotary evaporation in step S3 is 30-70°C, and the stirring is 10-100 r; The dialysis in step S3 includes pouring the liquid after rotary evaporation into a dialysis bag, suspending it in a beaker filled with a large amount of deionized water, and then slowly stirring and dialysing for 48-72 hours, and replacing the dialysis water every 4-12 hours; Dialysis bags have molecular weight cut-offs of 1000-7000 Da: The temperature of the secondary rotary evaporation in step S3 is 20-40° C., and the rotary evaporation is performed at 100-200 rpm.

9. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 1, characterized in that: The antioxidant includes one or more of di-tert-butyl-p-cresol, di-tert-butyl mixed phenol, dinonyldiphenylamine, and di-tert-butyl-4-hydroxyphenyl acrylate.

10. The wind turbine bearing grease composition with excellent anti-fretting wear performance according to claim 1, characterized in that: The metal deactivator is a benzotriazole derivative; The antioxidant and anticorrosive agent is thiophosphinothionyl zinc salt; The base oils are PAO40 and PAO100.

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