Universal bearing lubricating grease for wind generating set and preparation method of universal bearing lubricating grease

Abstract

According to the universal bearing lubricating grease for the wind generating set and the preparation method of the universal bearing lubricating grease, low-viscosity PAO, high-viscosity PAO, ester oil and alkyl naphthalene are selected as base oil, a composite lithium-calcium thickening agent, a tackifier, an antioxidant, a friction reducing agent, an extreme pressure agent, an anti-rust agent, a corrosion inhibitor and other additives are used as auxiliary materials, the obtained lubricating grease is high in universality, and the universal bearing lubricating grease has the advantages of prolonging the service life of a bearing and improving the service life of the bearing. The method has positive significance in reducing maintenance cost, improving power generation efficiency and economical efficiency, simplifying grease varieties, facilitating maintenance and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of grease preparation and provides a universal bearing grease for a wind generator set and a preparation method thereof. Background Art

[0002] With the deepening of the energy revolution, my country's wind power development has entered a new stage of large-scale, high-quality leapfrogging development. By March 2024, the total installed capacity of wind power in China will be about 460 million kilowatts, including 419 million kilowatts of onshore wind power and 38.03 million kilowatts of offshore wind power. While steadily promoting onshore wind power, we will vigorously develop offshore wind power. With the continuous advancement of technology and the continued growth of global demand for renewable energy, wind power will become an important part of the future energy structure.

[0003] The parts of the wind turbine that need lubrication mainly include the main gearbox, yaw and pitch gearbox, hydraulic control system, main bearing, yaw bearing pitch bearing, and generator bearing, among which the main bearing, pitch bearing, and yaw bearing are the core of the wind turbine transmission system. Once a failure occurs, it will bring great losses. In addition, my country's wind turbines are mostly concentrated in the northeast and northwest regions with severe winters, as well as in coastal areas and offshore continental shelves with hot summers, humid climates, and high salt content in the air. The operating environment is harsh. At the same time, wind farm equipment is located in the wild and at high altitudes, making equipment maintenance difficult and expensive. Therefore, the equipment is required to have good stability and reliability, and to minimize abnormal downtime caused by equipment lubrication failures.

[0004] Wind turbines cannot operate without lubrication. Lubrication products play a vital role in increasing wind energy production, maintaining equipment safety, extending wind turbine life, and reducing operating costs. As wind turbines develop towards larger sizes, the diameter and height of wind turbines are also increasing, which places strict requirements on the stability of various components and spare parts of wind power equipment, and also places high demands on lubricating materials. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a universal bearing grease for a wind turbine generator set and a preparation method thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention provides a universal bearing grease for a wind turbine generator set, which is prepared by mixing the following components in parts by weight: 10 to 30 parts of low-viscosity PAO, 20 to 40 parts of high-viscosity PAO, 10 to 15 parts of ester oil, 10 to 15 parts of alkyl naphthalene, 8 to 12 parts of 12-hydroxystearic acid, 2 to 3 parts of sebacic acid, 2 to 3 parts of lithium hydroxide, 0.3 to 0.5 parts of calcium hydroxide, 5 to 10 parts of a tackifier, 0.5 to 2 parts of an antioxidant, 1 to 4 parts of a friction reducer, 1 to 4 parts of an extreme pressure agent, 0.5 to 2 parts of a rust inhibitor, and 0.2 to 1 parts of a corrosion inhibitor.

[0008] As one of the preferred technical solutions, the low-viscosity PAO is selected from at least one of PAO3.5, PAO4, PAO6, PAO8, and PAO10, and the high-viscosity PAO is selected from at least one of PAO40, PAO65, PAO100, PAO150, and PAO300. As the main components of grease, low-viscosity PAO and high-viscosity PAO can meet the wide temperature requirements of -40 to 180°C, and can also use the lower traction coefficient characteristics of PAO to reduce friction resistance, thereby playing a role in energy saving and consumption reduction.

[0009] As one of the preferred technical solutions, the ester oil is selected from at least one of trimethylolpropane ester, dibasic acid diester, pentaerythritol ester, dipentaerythritol ester, trimellitic acid ester, polyester, and complex ester, which can improve and adjust the compatibility of PAO synthetic hydrocarbon base oil with sealing materials, so that the swelling, shrinkage and deformation of rubber materials are within a suitable range, and can also improve the solubility of additives in PAO synthetic hydrocarbon base oil, so as to better play the role of additives.

[0010] As one of the preferred technical solutions, the alkyl naphthalene is selected from at least one of AN5, AN8, AN12, AN15, AN20, and AN30, which can improve the structural stability of the composite lithium-calcium thickener, ensure the mechanical stability and colloidal stability of the grease, and also reduce the maximum refining temperature of the grease, thereby reducing energy consumption and production costs.

[0011] As one of the preferred technical solutions, the viscosity enhancer is selected from at least one of polyisobutylene, polymethacrylate, hydrogenated styrene-diene copolymer, and ethylene-propylene copolymer, wherein polyisobutylene can enhance the oil film strength of the grease, improve the adhesion of the grease to the friction metal surfaces of the main shaft, yaw and pitch bearings, and improve the lubricity; polymethacrylate can improve the viscosity-temperature properties of the lubricating oil, and can also offset the adverse effects of polyisobutylene on low-temperature performance; hydrogenated styrene-diene copolymer can improve the oil separation characteristics of the grease, and can enable it to continuously provide oil separation lubrication during the long-term operation of the main shaft, yaw and pitch bearings, avoiding problems such as drying of the grease and shortening of the service life caused by excessive oil separation in the early stage; ethylene-propylene copolymer can increase the viscosity and wire drawing of the grease, and improve the oil film strength.

[0012] As one of the further preferred technical solutions, the tackifier is a mixture of polyisobutylene, polymethacrylate and hydrogenated styrene-diene copolymer, wherein the hydrogenated styrene-diene copolymer accounts for 20% of the total amount of the tackifier.

[0013] As one of the further preferred technical solutions, the mass ratio of polyisobutylene to polymethacrylate is 1:1-3.

[0014] As one of the preferred technical solutions, the antioxidant is selected from at least one of diphenylamine, alkylated diphenylamine, diisooctyl diphenylamine, phenyl α-naphthylamine, 2,6-di-tert-butyl-p-cresol, and polymer sulfide phenol. The antioxidant can give the grease better antioxidant properties and thermal stability, extend the service life of the grease, and meet the long-term use requirements of wind power bearings.

[0015] As one of the preferred technical solutions, the friction reducer is selected from at least one of dialkyl dithiocarbamate molybdenum and dialkyl dithiophosphate oxymolybdenum. The friction reducer can provide good friction reduction and anti-wear protection for the metal friction surface of the bearing, while improving the load-bearing capacity of the grease, and can better protect the main shaft, yaw and pitch bearings under heavy loads and impact loads.

[0016] As one of the preferred technical solutions, the extreme pressure agent is selected from at least one of dialkyl zinc dithiophosphate, tricresol phosphate, triphenyl thiophosphate, isobutylene sulfide, thiocarbamate, and potassium borate oil. The extreme pressure agent can provide extreme pressure and lubricity to the grease, and can play a synergistic role with the friction reducer to better provide bearing lubrication protection.

[0017] As one of the preferred technical solutions, the rust inhibitor is selected from at least one of barium petroleum sulfonate, sodium petroleum sulfonate, zinc cyclohexane, barium dinonylnaphthalene sulfonate, N-oleoylsarcosine-octadecylamine salt, oxidized petroleum fat barium soap, and dodecenylsuccinic acid. The rust inhibitor provides the grease with the ability to resist water, steam, sea breeze and salt spray, protects the metal surface of the bearing from corrosion, and extends its service life.

[0018] As one of the preferred technical solutions, the corrosion inhibitor is selected from at least one of benzotriazole derivatives, thiadiazole derivatives, and benzotriazole. The corrosion inhibitor can protect the metal surface of the bearing from corrosion by polar elements such as sulfur and phosphorus in the friction reducer and extreme pressure agent, and can also play a synergistic anti-rust role with the rust inhibitor.

[0019] The present invention also provides a method for preparing the aforementioned universal bearing grease for a wind turbine generator set, and the specific steps are as follows:

[0020] S1. The low viscosity PAO, high viscosity PAO and alkyl naphthalene are mixed uniformly to obtain base oil I, and no more than 40 to 50% of the base oil I is put into the reactor, and 12-hydroxystearic acid, sebacic acid, lithium hydroxide and calcium hydroxide are added to the formula to obtain a composite lithium calcium thickener;

[0021] S2. The ester oil is added to the remaining base oil Ⅰ to obtain base oil Ⅱ; heated to 160 to 170 ℃, and 70% of the total mass of base oil Ⅱ is added;

[0022] S3. Continue heating to 190-200°C, stop heating after the material becomes thinner, stir for 3-5 minutes, add the remaining base oil II, cool naturally to 175-185°C, and stir for 30 minutes;

[0023] S4. Add the formulated amount of viscosity enhancer, stir evenly, circulate shear and cool;

[0024] S5. After cooling to 120 ° C, add the remaining amount of antioxidant, friction reducer, extreme pressure agent, rust inhibitor, corrosion inhibitor, stir well, homogenize and shear, and cool;

[0025] S6. Take samples for analysis below 80℃ and package after passing the test.

[0026] As one of the preferred technical solutions, in step S1, the composite lithium calcium thickener is prepared by the following method:

[0027] (a) adding 12-hydroxystearic acid into a reaction kettle and heating it to 90° C. until all the materials are melted;

[0028] (b) calcium hydroxide was prepared into a suspension using 3 times its weight of water, added into a reaction kettle, and the mixture was stirred and reacted for 10 minutes;

[0030] (c) dissolving the first portion of lithium hydroxide in water 5 to 6 times its weight to prepare a lithium hydroxide aqueous solution, and adding the reaction

[0031] In the kettle, continue to stir and react for 20 minutes;

[0032] (d) After the reaction is completed, the temperature is raised to 110° C., and the dibasic acid is added to the reaction kettle, and the mixture is stirred to melt the mixture;

[0033] (e) dissolving the second portion of lithium hydroxide in water 5 to 6 times its weight to prepare a lithium hydroxide aqueous solution, and adding the solution to the reaction mixture.

[0034] In the kettle, stir and react for 20 minutes;

[0035] (f) Raise the temperature to 160°C to ensure complete dehydration.

[0036] As one of the further preferred technical solutions, the mass ratio of the first part of lithium hydroxide to the second part of lithium hydroxide is 5:7.

[0037] The beneficial effects of the present invention are:

[0038] Based on a detailed and comprehensive analysis of the working conditions of three types of bearings, namely, main bearings, variable pitch bearings, and yaw bearings, the present invention provides a universal bearing grease suitable for main shaft bearings, yaw bearings, variable pitch bearings, etc. of wind turbine generator sets and a preparation method thereof through the optimization and screening of base oil, thickener, and additives. The grease of the present invention can meet the use requirements of these three types of wind turbine bearings and is a highly versatile wind turbine bearing grease, which has positive significance for extending the service life of bearings, reducing maintenance costs, improving power generation efficiency and economy, simplifying grease varieties, and facilitating maintenance.

[0039] The present invention selects low-viscosity PAO, high-viscosity PAO, ester oil and alkyl naphthalene as base oils. In order to ensure that the grease can meet the stringent use requirements of the main shaft, yaw and pitch bearings, it is necessary to optimize the compatibility of the four types of base oils. The kinematic viscosity of the base oil at 40°C ranges from 50 to 500 mm 2 / s, preferably 60~200mm 2 / s. Other indicators include base oil viscosity index not less than 140, pour point not higher than -40℃, flash point not lower than 260℃, all of which are used to ensure the high and low temperature resistance, viscosity-temperature resistance and appropriate oil film thickness of the grease. Specifically, low-viscosity PAO and high-viscosity PAO are combined as the main components of the base oil to ensure that the grease has good high and low temperature resistance and meets the wide temperature requirements of -40 to 180℃. Its lower traction coefficient can also be used to reduce friction resistance, while playing a role in energy saving and consumption reduction; the base oil is supplemented with ester oil, which can not only improve and adjust the compatibility of PAO synthetic hydrocarbon base oil with sealing materials, so that the swelling, shrinkage and deformation of rubber materials are within a suitable range, but also improve the solubility of additives in PAO synthetic hydrocarbon base oil, so as to better play the role of additives; the base oil is supplemented with alkyl naphthalene, which can not only improve the structural stability of the composite lithium calcium thickener, ensure the mechanical stability and colloidal stability of the grease, but also reduce the maximum refining temperature of the grease, reduce energy consumption and production costs.

[0040] Thickener is the skeleton of grease, and has a great influence on the fretting resistance, mechanical stability, colloidal stability and water resistance of grease. The present invention selects composite lithium calcium as the thickener, and introduces calcium soap into the composite lithium to improve the water resistance and lubricity of the grease. At the same time, the introduction of calcium soap has no adverse effect on the mechanical stability, colloidal stability, high temperature resistance and fretting resistance of the composite lithium grease.

[0041] The present invention innovatively uses polyisobutylene, polymethacrylate and hydrogenated styrene-diene copolymer to optimize the compatibility of three components to prepare a tackifier. Among them, polyisobutylene can enhance the oil film strength of the grease and improve the adhesion of the grease to the friction metal surface of the main shaft, yaw and pitch bearings; polymethacrylate can improve the viscosity-temperature property of the lubricating oil and offset the adverse effect of polyisobutylene on low temperature performance; hydrogenated styrene-diene copolymer can improve the oil separation characteristics of the grease, so that it can continuously provide oil separation lubrication during the long-term operation of the main shaft, yaw and pitch bearings, avoiding the problems of grease drying and shortening of service life caused by excessive oil separation in the early stage.

[0042] The lubricating grease of the present invention has the following characteristics:

[0043] 1. Excellent anti-fretting wear performance. When the yaw bearing and pitch bearing are subjected to wind load or slight vibration of the control system, the excellent anti-fretting wear characteristics of the composite lithium calcium grease are used to avoid poor lubrication phenomena such as adhesion, brinell wear and welding, thereby extending the service life of the bearing;

[0044] 2. Good shear stability ensures that the grease will not become thinner and then lose during the long-term operation of the bearing, especially the spindle bearing, resulting in loss of protection for the bearing;

[0045] 3. Suitable viscosity and oil separation and release characteristics, excellent colloid stability, which not only ensures that the grease has better fluidity and is easy to flow back to the friction surface for lubrication, but also avoids adhesion and insufficient protection to the bearing caused by too low viscosity;

[0046] 4. Excellent extreme pressure and wear resistance, protecting the main shaft, yaw and pitch bearings from pitting, excessive wear, abrasion, bonding and other poor lubrication phenomena under heavy load and impact load;

[0047] 5. Excellent low-temperature starting and pumping performance ensures that the main shaft, yaw and pitch bearings still have very low starting torque even at -40°C, avoiding the influence of grease hardening at low temperature on the starting and operation of the bearings;

[0048] 6. Good high temperature and viscosity-temperature properties, which can meet the requirements of use in my country's entire climate conditions and extreme high temperatures in summer within a wide temperature range of -40℃ to 180℃, avoiding the obvious decrease in grease viscosity with increasing temperature and loss of lubricity at high temperatures;

[0049] 7. Excellent anti-rust, anti-corrosion and water resistance, can provide long-term lubrication for the main shaft, yaw and pitch bearings in harsh environments such as rain, snow, humid sea breeze, sand and dust, so as to protect them from corrosion and extend their service life;

[0050] 8. Good compatibility of sealing materials to avoid deformation and failure of sealing materials due to grease;

[0051] 9. It has a very long service life and oil change cycle, which can simplify the types of oils and fats, reduce maintenance costs, and improve power generation efficiency and economy.

[0052] In summary, the present invention adopts a scientifically designed base oil combination to meet the requirements of the main shaft, yaw, pitch and other bearings of the wind turbine for grease adhesion, high and low temperature resistance, sealing material compatibility, colloid stability and the like; further, the viscosity enhancer adopts three types of combination, which not only ensures the oil film strength and adhesion of the grease, but also has good oil separation and release characteristics; further, the thickener adopts a composite lithium calcium soap, and is combined with a friction reducer, extreme pressure agent, rust inhibitor, corrosion inhibitor and antioxidant with excellent compatibility, which can cooperate with each other on the metal surface of the bearing and meet the stringent use requirements of the main shaft, yaw, pitch and other bearings of the wind turbine. The grease of the present invention has excellent anti-fretting wear, good shear stability, suitable viscosity and oil separation release characteristics, excellent extreme pressure anti-wear, excellent low-temperature starting and pumping properties, good high temperature and viscosity-temperature properties, excellent rust and corrosion resistance and water resistance, good sealing material compatibility, and very long service life and oil change cycle, which can simplify grease varieties, reduce maintenance costs, and improve power generation efficiency and economy.

[0053] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with specific implementation modes.

[0055] Example 1

[0056] A method for preparing universal bearing grease for wind turbine generator sets, the specific steps are as follows:

[0057] 1) 110 g of PAO6, 340 g of PAO40 and 100 g of alkyl naphthalene AN15 were mixed to obtain base oil I, and 50% of the base oil I was put into a reactor;

[0058] 2) 100 g of 12-hydroxystearic acid was added into a reaction kettle and heated to 90° C. until all the materials were melted;

[0059] 3) 4 g of calcium hydroxide was prepared into a suspension with 3 times its weight of water and added into the reactor, and the mixture was stirred and reacted for 10 minutes;

[0060] 4) Dissolve 10 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it into the reaction kettle, and continue to stir and react for 20 minutes;

[0061] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0062] 6) Dissolve 14 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it to the reaction kettle, and stir and react for 20 minutes at a temperature of 100 °C;

[0063] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0064] 8) Add 100 g of trimethylolpropane ester to the remaining base oil I to obtain base oil II. When the material temperature reaches 160° C., add 70% of base oil II and continue to heat up;

[0065] 9) Stop heating when the temperature reaches 190-200°C, stir for 3-5 minutes, add the remaining base oil II, cool to between 175-185°C, and stir for 30 minutes;

[0066] 10) Add 40g polyisobutylene, 40g polymethacrylate, and 20g hydrogenated styrene-diene copolymer, stir well and then

[0067] Cyclic shearing and cooling;

[0068] 11) Add 30g of dialkyl dithiophosphate oxymolybdenum, 20g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and circulate cooling;

[0069] 12) Sampling and analysis below 80°C;

[0070] 13) Packing after passing the test.

[0071] Example 2

[0072] A method for preparing universal bearing grease for wind turbine generator sets, the specific steps are as follows:

[0073] 1) 120 g of PAO4, 330 g of PAO65 and 100 g of alkyl naphthalene AN23 were mixed to obtain base oil I, and 50% of the base oil I was put into a reactor;

[0074] 2) 100 g of 12-hydroxystearic acid was added into a reaction kettle and heated to 90° C. until all the materials were melted;

[0075] 3) 4g of calcium hydroxide was prepared into a suspension with 3 times its weight of water, added to the reactor, and stirred for 10 minutes.

[0076] minute;

[0077] 4) dissolving 10 g of lithium hydroxide in 6 times its weight of water to prepare a lithium hydroxide aqueous solution, adding the solution to the reaction kettle, and continuing to stir and react at the temperature for 20 minutes;

[0078] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0079] 6) dissolving 14 g of lithium hydroxide in 6 times its weight of water to prepare a lithium hydroxide aqueous solution, adding the solution to the reaction kettle, and reacting with stirring at the temperature for 20 minutes;

[0080] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0081] 8) Add 100g of sebacic acid diester to the remaining base oil I to obtain base oil II. When the material temperature is 160°C, add

[0082] 70% base oil II, continue to heat up;

[0083] 9) Stop heating when the temperature reaches 190-200°C, stir for 3-5 minutes, add the remaining base oil II, cool to between 175-185°C, and stir for 30 minutes;

[0084] 10) Add 40g polyisobutylene, 40g polymethacrylate and 20g hydrogenated styrene-diene copolymer at about 160°C, stir well and continue to cool;

[0085] 11) Add 30g of dialkyl dithiophosphate oxymolybdenum, 20g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and cool;

[0086] 12) Sampling and analysis below 80°C;

[0087] 13) Packing after passing the test.

[0088] Example 3

[0089] A method for preparing universal bearing grease for wind turbine generator sets, the specific steps are as follows:

[0090] 1) 120 g of PAO6, 330 g of PAO40 and 100 g of alkyl naphthalene AN15 were mixed to obtain base oil I, and 50% of the base oil I was put into a reactor;

[0091] 2) 100 g of 12-hydroxystearic acid was added into a reaction kettle and heated to 90° C. until all the materials were melted;

[0092] 3) 4g of calcium hydroxide was prepared into a suspension with 3 times its weight of water, added to the reactor, and stirred for 10 minutes.

[0093] minute;

[0094] 4) Dissolve 10 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it into the reaction kettle, and continue to stir and react for 20 minutes;

[0095] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0096] 6) Dissolve 14 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it to the reaction kettle, and stir and react for 20 minutes at a temperature of 100 °C;

[0097] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0098] 8) Add 100 g of trimethylolpropane ester to the remaining base oil I to obtain base oil II. When the material temperature reaches 160° C., add 70% of base oil II and continue to heat up;

[0099] 9) Stop heating when the temperature reaches 190-200°C, stir for 3-5 minutes, add the remaining base oil II, cool to between 175-185°C, and stir for 30 minutes;

[0100] 10) Add 20g polyisobutylene, 60g polymethacrylate and 20g hydrogenated styrene-diene copolymer at about 160°C, stir well and continue to cool;

[0101] 11) Add 40g of dialkyl dithiophosphate oxymolybdenum, 10g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and cool;

[0102] 12) Sampling and analysis below 80℃

[0103] 13) Packing after passing the test.

[0104] Example 4

[0105] A method for preparing universal bearing grease for wind turbine generator sets, the specific steps are as follows:

[0106] 1) 120 g of PAO4, 330 g of PAO65 and 100 g of alkyl naphthalene AN15 were mixed to obtain base oil I, and 50% of the base oil I was put into a reactor;

[0107] 2) 100 g of 12-hydroxystearic acid was added into a reaction kettle and heated to 90° C. until all the materials were melted;

[0108] 3) 4 g of calcium hydroxide was prepared into a suspension with 3 times its weight of water, added into a reaction kettle, and stirred for 10 minutes under heat preservation;

[0109] 4) dissolving 10 g of lithium hydroxide in 6 times its weight of water to prepare a lithium hydroxide aqueous solution, adding the solution to the reaction kettle, and continuing to stir and react at the temperature for 20 minutes;

[0110] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0111] 6) Dissolve 14 g of lithium hydroxide in water 6 times its weight to prepare a lithium hydroxide aqueous solution, add the solution to the reaction kettle, and stir the reaction for 20 minutes under heat preservation;

[0112] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0113] 8) Add 100 g of trimethylolpropane ester to the remaining base oil I to obtain base oil II. When the material temperature reaches 160° C., add 70% of base oil II and continue to heat up;

[0114] 9) Stop heating when the temperature reaches 190-200℃, stir for 3-5 minutes, add the remaining base oil II and cool to 170-190℃

[0115] Stir for 30 minutes;

[0116] 10) Add 20g polyisobutylene, 60g polymethacrylate and 20g hydrogenated styrene-diene copolymer at about 160°C, stir well and continue to cool;

[0117] 1) Add 40g of dialkyl dithiophosphate oxymolybdenum, 10g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and cool;

[0118] 2) Sampling and analysis below 80°C;

[0119] 3) Packing after passing the test.

[0120] Comparative Example 1

[0121] Comparative Example 1 includes the following preparation process (alkyl naphthalene is removed compared with Example 1):

[0122] 1) 160 g of PAO6 and 390 g of PAO40 were mixed to obtain base oil I, and 50% of base oil I was put into a reactor; 2) 100 g of 12-hydroxystearic acid was put into a reactor and heated to 90° C. until all the materials were melted;

[0123] 3) 4g of calcium hydroxide was prepared into a suspension with 3 times its weight of water, added to the reactor, and stirred for 10 minutes.

[0124] minute;

[0125] 4) Dissolve 10 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it into the reaction kettle, and continue to stir and react for 20 minutes;

[0126] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0127] 6) Dissolve 14 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it to the reaction kettle, and stir and react for 20 minutes at a temperature of 100 °C;

[0128] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0129] 8) Add 100 g of trimethylolpropane ester to the remaining base oil I to obtain base oil II. When the material temperature reaches 160° C., add 70% of base oil II and continue to heat up;

[0130] 9) Stop heating when the temperature reaches 190-200°C, stir for 3-5 minutes, add the remaining base oil I, cool to between 175-185°C, and stir for 30 minutes;

[0131] 10) Add 40g polyisobutylene, 40g polymethacrylate and 20g hydrogenated styrene-diene copolymer at about 160°C, stir well and continue to cool;

[0132] 11) Add 30g of dialkyl dithiophosphate oxymolybdenum, 20g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and cool;

[0133] 12) Sampling and analysis below 80°C;

[0134] 13) Packing after passing the test.

[0135] Comparative Example 2

[0136] Comparative Example 2 includes the following preparation process (compared with Example 1, the hydrogenated styrene-diene copolymer is removed):

[0137] 1) 120 g of PAO6, 330 g of PAO40 and 100 g of alkyl naphthalene AN15 were mixed to obtain base oil I, and 50% of the base oil I was put into a reactor;

[0138] 2) 100 g of 12-hydroxystearic acid was added into a reaction kettle and heated to 90° C. until all the materials were melted;

[0139] 3) 4g of calcium hydroxide was prepared into a suspension with 3 times its weight of water, added to the reactor, and stirred for 10 minutes.

[0140] minute;

[0141] 4) Dissolve 10 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it into the reaction kettle, and continue to stir and react for 20 minutes;

[0142] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0143] 6) Dissolve 14 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it to the reaction kettle, and stir and react for 20 minutes at a temperature of 100 °C;

[0144] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0145] 8) Add 100 g of trimethylolpropane ester to the remaining base oil I to obtain base oil II. When the material temperature reaches 160° C., add 70% of base oil II and continue to heat up;

[0146] 9) Stop heating when the temperature reaches 190-200°C, stir for 3-5 minutes, add the remaining base oil II, cool to between 175-185°C, and stir for 30 minutes;

[0147] 10) Add 60g polyisobutylene and 40g polymethacrylate at about 160°C, stir well and continue to cool;

[0148] 11) Add 30g of dialkyl dithiophosphate oxymolybdenum, 20g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and cool;

[0149] 12) Sampling and analysis below 80℃

[0150] 13) Packing after passing the test.

[0151] Comparative Example 3

[0152] Comparative Example 3 includes the following preparation process (the ester oil is removed compared with Example 1):

[0153] 1) 160g PAO6, 390g PAO40100g, 100g alkyl naphthalene AN15 were mixed to obtain base oil I, and 50%

[0154] The base oil Ⅰ is put into the reactor;

[0155] 2) 100 g of 12-hydroxystearic acid was added into a reaction kettle and heated to 90° C. until all the materials were melted;

[0156] 3) 4g of calcium hydroxide was prepared into a suspension with 3 times its weight of water, added to the reactor, and stirred for 10 minutes.

[0157] minute;

[0158] 4) Dissolve 10 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it into the reaction kettle, and continue to stir and react for 20 minutes;

[0159] 5) After the reaction is completed, heat the reaction mixture to 110°C, add 30 g of sebacic acid into the reaction vessel, and stir to melt the mixture;

[0160] 6) Dissolve 14 g of lithium hydroxide in 5 times its weight of water to prepare a lithium hydroxide aqueous solution, add it to the reaction kettle, and stir and react for 20 minutes at a temperature of 100 °C;

[0161] 7) Raise the temperature to 160°C to ensure complete dehydration;

[0162] 8) When the material temperature reaches 160°C, add 70% of the remaining base oil I and continue to heat up;

[0163] 9) Stop heating when the temperature reaches 190-200℃, stir for 3-5 minutes, add the remaining base oil I, and cool to 175-185℃

[0164] Stir for 30 minutes;

[0165] 10) Add 40g polyisobutylene, 40g polymethacrylate and 20g hydrogenated styrene-diene copolymer at about 160°C, stir well and continue to cool;

[0166] 11) Add 30g of dialkyl dithiophosphate oxymolybdenum, 20g of dialkyl dithiophosphate zinc, 10g of diisooctyl diphenylamine, 10g of barium petroleum sulfonate, and 2g of benzotriazole derivative at 120°C, stir well, perform homogenization shearing, and cool;

[0167] 12) Sampling and analysis below 80°C;

[0168] 13) Packing after passing the test.

[0169] The main properties of the greases prepared according to the above examples and comparative examples are shown in Table 1.

[0170] Table 1 Comparison of main properties of a universal bearing grease for wind turbine generator set in an embodiment and a comparative example

[0171]

[0172] The specific test items in Table 1 are as follows:

[0173] 1. Appearance: Appearance is the visual inspection of the external state of the product, including hardness, color, fluidity, etc. Appearance can be used to preliminarily judge the performance and state of the grease. Appearance inspection is mainly carried out by naked eye observation;

[0174] 2. Cone penetration: Cone penetration is a technical indicator that reflects the hardness of grease. The larger the value, the thinner the consistency, that is, the softer it is. The cone penetration of grease is divided into non-working cone penetration (applicable to semi-fluid grease, grease with very high consistency and hardness, grease with high viscosity, and other greases and lubricants that are not convenient for workmanship testing), working cone penetration, and extended working cone penetration (used to measure the consistency of grease after 10,000 or 100,000 working shears, which is one of the indicators reflecting mechanical stability). The cone penetration test instrument is a grease cone penetration tester, and the test standard is GB / T 269;

[0175] 3. Dropping point: When heated under specified conditions, the grease softens as the temperature rises. The temperature when the first drop drips from the grease cup of the instrument or when it touches the bottom of the test tube in a column (the temperature point at which the grease changes from solid to liquid) is called the dropping point of the grease. The dropping point of the grease is one of the important indicators that reflect the high-temperature performance of the grease and is an important indicator for users to select grease. The dropping point is directly related to the type of thickener of the grease. The dropping point detection instrument is a grease wide temperature range dropping point tester, and the detection standard is GB / T 3498;

[0176] 4. Steel mesh oil separation: Under high temperature conditions, the amount of base oil pressed out by the grease's own weight is an important indicator of the colloid stability of the grease under high temperature conditions. The steel mesh oil separation detection instrument is a grease steel mesh oil separator, and the detection standard is NB / SH / T 0324;

[0177] 5. Metal sheet corrosion: Immerse a polished standard-sized metal sheet in grease, keep the temperature and time as required, then take it out and observe its surface color and corrosion degree to determine the corrosion level. This project mainly reflects the degree of corrosion influence of substances in grease (especially extreme pressure anti-wear additives in grease) on metal sheets. The corrosion detection instrument is a petroleum product corrosion tester.

[0178] The testing standards are GB / T 7326 (T2 copper sheet), GB / T 5096 (T2 copper sheet), SH / T 0331 (steel sheet, T3 copper sheet); 6. Evaporation loss: the weight of a specified weight of grease lost at a set temperature and time. Evaporation loss reflects the grease

[0179] Indicator of high temperature performance. The evaporation loss test standard is GB / T 7325;

[0180] 7. Anti-corrosion: It is suitable for measuring the anti-corrosion performance of grease under humid conditions using tapered roller bearings coated with grease, and is used to reflect the protective performance of grease on metal materials under humid conditions. The test standard is GB / T5018; 8. Maximum non-seizure load P B : Maximum no-seizure load P B It is one of the indicators that reflects the lubricating performance of lubricants and is also a reflection of the

[0181] The ability to reduce friction under a certain load and prevent abnormal working conditions such as seizure of metal parts. The larger the value, the better the lubricity. The maximum non-seizure load test instrument is a four-ball friction tester, and the test standards are SH / T 0202, GB / T

[0182] 12583, GB / T 3142;

[0183] 9. Sintering load P D : Sintering load P D It is one of the indicators that reflect the lubricating performance of lubricants. The higher the sintering load, the better the extreme pressure performance of the grease. The sintering load detection instrument is a four-ball friction tester, and the detection standards are SH / T 0202, GB / T

[0184] 12583, GB / T 3142;

[0185] 10. Wear spot diameter: Wear spot diameter is an indicator of the anti-wear performance of lubricating grease. The smaller the wear spot diameter, the better the anti-wear performance. The wear spot diameter detection instrument is a four-ball friction tester, and the detection standards are SH / T 0204 and SH / T 0189; 11. Rubber compatibility: It is an indicator that reflects the shrinkage or swelling of rubber materials in different lubricants.

[0186] It is a very important indicator for lubricants in contact with materials. If the rubber compatibility is a negative value, it indicates that it shrinks. If the shrinkage is too large, the rubber may become hard, brittle, or cracked during use, which may cause seal failure. If the rubber compatibility is a positive value, it indicates that it swells. If the swelling is too large, the rubber may soften and swell during use, which may also cause seal failure. Good rubber compatibility requires that the rubber has appropriate shrinkage or swelling in the grease. Generally, within ±10%, it indicates good compatibility, and within ±6%, it is excellent. The testing standards are SH / T 0429,

[0187] NB / SH / T 0877, etc.

[0188] 12. Similar viscosity: The viscosity of grease under certain temperature conditions changes with the shear rate. This viscosity is called similar viscosity, which is an important indicator of the low-temperature performance of grease. The standard for determining similar viscosity of grease is SH / T 0048;

[0189] The following conclusions can be drawn from Table 1:

[0190] Compared with Example 1, Example 2 differs in that the types and ratios of high and low viscosity PAOs in the base oil are adjusted, as well as the types of ester oils, but four types of base oils are retained. The analysis data of the greases are not much different, and the analysis and testing data of the greases, especially the mechanical stability, colloid stability, extreme pressure anti-wear and low temperature performance data are basically the same, indicating that only adjusting the four types of base oils in the base oil has little effect on the physical and chemical properties of the general grease for wind turbine bearings.

[0191] Example 3 is compared with Example 1, the difference is that the amount of thickeners polyisobutylene and polymethacrylate is adjusted but the three thickeners and the amount of hydrogenated styrene-diene copolymer are retained. The analysis data of the grease are compared and the difference is not much, especially the steel mesh oil separation project, which shows that the formula guarantees the presence of three thickeners hydrogenated styrene-diene copolymer and polyisobutylene and polymethacrylate, and only adjusts their proportions, which will not affect the various physical and chemical properties of the grease. In particular, the combination of the three thickeners has good oil separation release and control characteristics. It can control the oil separation amount not to be too large, so as to avoid the grease from drying and hardening due to excessive oil separation during long-term use, affecting the normal operation of the fan main shaft, variable pitch and yaw systems, and can provide an appropriate amount of oil separation to ensure that the bearing raceway has sufficient lubrication, avoid dry friction and poor lubrication, and affect the long-term operation of each bearing system.

[0192] Compared with Example 1, Example 4 differs in that the types and ratios of high and low viscosity PAOs are adjusted, and the amounts of tackifiers polyisobutylene and polymethacrylate are adjusted. The analysis data of the greases are similar, indicating that the ratios of the four types of base oils and the three tackifiers are adjusted, but these key components are retained, which has little effect on the physical and chemical properties of the general grease for wind turbine bearings, including mechanical stability, colloidal stability, extreme pressure anti-wear and low temperature performance, and does not affect the application of the formula component products in wind turbine bearings.

[0193] The comprehensive description ensures that the four base oil types remain unchanged and the three types of viscosity enhancers are guaranteed. Only the ratio of the base oils and the ratio of the viscosity enhancers are adjusted, which does not affect the main and key physical and chemical properties of the grease of the present invention, such as mechanical stability, colloidal stability, extreme pressure anti-wear and low temperature performance.

[0194] Comparative Example 1 is compared with Example 1, indicating that the removal of alkyl naphthalene, at the same thickening amount, the consistency of the grease becomes thinner obviously, indicating that the removal of alkyl naphthalene will affect the formation of a stable and uniform colloidal structure of the grease, and has a great influence on the thickening ability of the grease; the shear data of 100,000 times becomes larger, indicating that the mechanical stability of the grease becomes worse, which will cause the grease to become thinner and then lose during long-term use, and will cause poor lubrication of components such as bearings, seriously affecting the use of main shafts, variable pitch and yaw bearings and even causing accidents, which is unacceptable for the operation and maintenance of the fan; at the same time, the steel mesh oil separation also becomes larger, indicating that the colloidal stability of the grease is also worse, and excessive oil separation may cause the grease to dry out in the later stage and affect the performance of the bearing, which is a potential hidden danger to the operation of the fan. Comprehensive explanation Alkyl naphthalene is a necessary component in the formula of the present invention, which has a great influence on the fat-forming property, colloidal stability and mechanical stability of the grease.

[0195] Comparison of Comparative Example 2 with Example 1 shows that after removing the hydrogenated styrene-diene copolymer, the oil separation of the steel mesh of the grease increases significantly. The increase in the oil separation of the steel mesh indicates that the colloidal stability of the grease has also deteriorated. Excessive oil separation may cause the grease to dry out in the later stage and thus affect the performance of the bearing, which is a potential hidden danger to the operation of the wind turbine. It shows that the hydrogenated styrene-diene copolymer is a necessary component of the formula of the present invention. In combination with the other two tackifiers, the colloidal stability of the grease is greatly improved, which can well ensure that the universal grease for wind power bearings has good comprehensive performance and performance.

[0196] Comparative Example 3 is compared with Implementation 1, which shows that after removing the ester oil, at the same thickening amount, the consistency of the grease becomes slightly thinner, indicating that removing the ester oil will affect the formation of a stable and uniform colloid structure of the grease, and has a certain effect on the thickening ability of the grease; the 100,000 shear data becomes larger, indicating that the mechanical stability of the grease deteriorates, which will cause the grease to become thinner and then lose during long-term use, causing poor lubrication of components such as bearings, seriously affecting the use of main shafts, variable pitch and yaw bearings, and even causing accidents, which is unacceptable for the operation and maintenance of the fan; at the same time, the rubber of the grease also shrinks significantly, indicating that the rubber compatibility has deteriorated. Comprehensive explanation: ester oil is a necessary component in the formula of the present invention, which has a great influence on the grease-forming properties, rubber compatibility, mechanical stability, and colloid stability of the grease.

[0197] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A universal bearing grease for wind turbine generator set, characterized in that: The invention is prepared by mixing the following components in parts by weight: 10 to 30 parts of low-viscosity PAO, 20 to 40 parts of high-viscosity PAO, 10 to 15 parts of ester oil, 10 to 15 parts of alkyl naphthalene, 8 to 12 parts of 12-hydroxystearic acid, 2 to 3 parts of sebacic acid, 2 to 3 parts of lithium hydroxide, 0.3 to 0.5 parts of calcium hydroxide, 5 to 10 parts of viscosity enhancer, 0.5 to 2 parts of antioxidant, 1 to 4 parts of friction reducer, 1 to 4 parts of extreme pressure agent, 0.5 to 2 parts of rust inhibitor and 0.2 to 1 parts of corrosion inhibitor.

2. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The low-viscosity PAO is selected from at least one of PAO3.5, PAO4, PAO6, PAO8, and PAO10, and the high-viscosity PAO is selected from at least one of PAO40, PAO65, PAO100, PAO150, and PAO300.

3. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The ester oil is selected from at least one of trimethylolpropane ester, dibasic acid diester, pentaerythritol ester, dipentaerythritol ester, trimellitic acid ester, polyester and complex ester.

4. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The alkyl naphthalene is selected from at least one of AN5, AN8, AN12, AN15, AN20, and AN30.

5. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The tackifier is selected from at least one of polyisobutylene, polymethacrylate, hydrogenated styrene-diene copolymer and ethylene-propylene copolymer.

6. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The antioxidant is selected from at least one of diphenylamine, alkylated diphenylamine, diisooctyl diphenylamine, phenyl α-naphthylamine, 2,6-di-tert-butyl-p-cresol and high molecular weight thioether phenol.

7. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The friction reducer is selected from at least one of dialkyl molybdenum dithiocarbamate and dialkyl molybdenum dithiophosphate.

8. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The extreme pressure agent is selected from at least one of zinc dialkyl dithiophosphate, tricresyl phosphate, triphenyl thiophosphate, isobutylene sulfide, thiocarbamate, and potassium borate oil.

9. The universal bearing grease for wind turbine generator set according to claim 1, characterized in that: The rust inhibitor is selected from at least one of barium petroleum sulfonate, sodium petroleum sulfonate, zinc naphthenate, barium dinonylnaphthalene sulfonate, N-oleoylsarcosine-octadecylamine salt, oxidized petroleum fat barium soap, and dodecenylsuccinic acid; The corrosion inhibitor is selected from at least one of benzotriazole derivatives, thiadiazole derivatives and benzotriazole.

10. The method for preparing a universal bearing grease for a wind turbine generator set according to any one of claims 1 to 9, characterized in that: The specific steps are as follows: S1. The low viscosity PAO, high viscosity PAO and alkyl naphthalene are mixed uniformly to obtain base oil I, and no more than 40 to 50% of the base oil I is put into the reactor, and 12-hydroxystearic acid, sebacic acid, lithium hydroxide and calcium hydroxide are added to the formula to obtain a composite lithium calcium thickener; S2. The ester oil is added to the remaining base oil Ⅰ to obtain base oil Ⅱ; heated to 160 to 170 ℃, and 70% of the total mass of base oil Ⅱ is added; S3. Continue heating to 190-200°C, stop heating after the material becomes thinner, stir for 3-5 minutes, add the remaining base oil II, cool naturally to 175-185°C, and stir for 30 minutes; S4. Add the formulated amount of viscosity enhancer, stir evenly, circulate shear and cool; S5. After cooling to 120 ° C, add the remaining amount of antioxidant, friction reducer, extreme pressure agent, rust inhibitor, corrosion inhibitor, stir well, homogenize and shear, and cool; S6. Take samples for analysis below 80℃ and package after passing the test.

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