Wide-temperature-range lubricating grease for transmission system of helicopter as well as preparation method and application of wide-temperature-range lubricating grease

Abstract

The invention belongs to the technical field of lubricating materials and particularly relates to wide-temperature-range lubricating grease for a helicopter transmission system as well as a preparation method and application of the wide-temperature-range lubricating grease. The wide-temperature-range lubricating grease for the helicopter transmission system comprises the following components: base oil, a thickening agent, a tribological property improver, an antioxidant, an adhesive and an antirust agent, the tribological performance improver is prepared from oxymolybdenum thiodibutyl dithiocarbamate, antimony dibutyl dithiocarbamate, tricresyl phosphate and bismuth sulfide according to the mass ratio of (3 to 5) to 1 to (1 to 3) to (0.1 to 1.5). The wide-temperature-range lubricating grease for the helicopter transmission system, provided by the invention, has outstanding high-temperature oxidation resistance, excellent extreme-pressure wear resistance and high-temperature performance and excellent low-temperature starting and operating torque, and can meet the use requirements of a lubricating grease product for the helicopter transmission system on wide temperature range and high load.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lubricating materials, and particularly relates to a wide-temperature-range lubricating grease for a helicopter transmission system and a preparation method and application thereof. BACKGROUND

[0002] As one of the three key moving parts of a helicopter, the main function of the transmission system is to transmit power from the engine to the main rotor, tail rotor and other accessories, so that the helicopter can overcome various resistances and realize the predetermined flight action. The engine is usually horizontally installed, and the transmission system changes the rotation direction from the output shaft (longitudinal direction) of the engine to the rotor shaft (vertical direction) and the tail rotor shaft (lateral direction), so that the rotor can provide vertical pull, and the tail rotor can provide lateral pull. At the same time, between the input end of the main reducer and the output end of the engine, a freewheel unit is installed, when the rotor rotation speed is greater than the engine driving speed, the rotor and the engine are completely disconnected and rotate freely; when the engine fails, it can be used for autorotation glide landing. Therefore, the transmission system needs to bear the aerodynamic load of the main rotor and the tail rotor.

[0003] Compared with the traditional lubricating oil of the helicopter, the lubricating grease has the following technical characteristics: first, the anti-bullet capability is strong, the traditional lubricating oil is easy to lose, the lubricating grease is in a paste state and is easy to remain on the sliding surface, is not easy to lose and leak, and can maintain stability for a long time, so the anti-bullet capability can be greatly improved; second, the internal structure is relatively simple, in order to effectively lubricate the gears, bearings and other parts, the lubricating oil has complex oil circuit, oil pocket and other oil collection structures, and the lubricating grease does not need to design complex oil passage and oil collection structure; third, it is beneficial to reduce the weight, the lubricating grease has the characteristics of adhesion, shear and centrifugal stability, anti-wear property and the like, compared with the lubricating oil, the amount of the lubricating grease can be reduced to achieve the lubricating effect, and the oil pool does not need to be designed to reduce the weight; fourth, the sealing property is strong, the lubricating grease can effectively seal the pollutants and dust, and has excellent anti-rust property and thermal oxidation stability. If the transmission system is designed by using the grease lubrication, the weight can be appropriately reduced under the premise of ensuring that the reliability is not reduced, and the anti-bullet capability of the transmission system and the survival capability of the helicopter can be significantly improved.

[0004] Chinese patent application CN1333053A discloses an aircraft wheel lubricating grease and a preparation method thereof. Based on the total weight of the lubricating grease, the following components are included: (a) 5-45% of ethyl silicone oil base oil; (b) 3-25% of a composite lithium and calcium soap thickener; (c) 2-20% of graphite powder additive; (d) 0.1-5.0% of phosphate ester additive; (e) 0.01-3.0% of aromatic amine antioxidant additive; (f) 0.01-3.0% of benzotriazole fatty acid amine salt anti-rust additive; and (g) the balance of poly-alpha olefin oil base oil.

[0005] Another Chinese invention patent application CN112877121A discloses a lubricating grease and its preparation method and application, the lubricating grease comprises the following components by mass percentage: base oil 84-97%, thickening agent 2-10%, antioxidant 0-4%, antirust agent 0-4%, extreme pressure anti-wear agent 0-4%; wherein, the base oil has a 40℃ kinematic viscosity of 20-150mm 2 / s; the thickening agent is obtained by reaction of dodecylhydroxy stearic acid, stearic acid and lithium hydroxide.

[0006] However, the above-mentioned patent provides a lubricating grease which does not have good wide temperature range adaptability and wear resistance, and the lubricating grease used for helicopter transmission system must meet the technical requirements defined in the specific standard specification, and under the condition of meeting the physical and chemical properties, it must pass professional test and application before being used in matching, so as to ensure the safety and reliability of the helicopter transmission system.

[0007] In view of this, there is an urgent need in the art to develop a wide temperature range lubricating grease for helicopter transmission system which has excellent wide temperature range adaptability and wear resistance, and has simple preparation process and low cost. SUMMARY

[0008] The present application provides a wide temperature range lubricating grease for helicopter transmission system and its preparation method and application to solve the problem of wide temperature range adaptability of the lubricating grease for helicopter transmission system, and the lubricating grease has excellent shear resistance, wear resistance, impact resistance and adhesion.

[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0010] A wide temperature range lubricating grease for helicopter transmission system comprises the following components: base oil, thickening agent, tribological property improver, antioxidant, adhesion agent and antirust agent.

[0011] Preferably, the tribological property improver is composed of mass ratio of 3-5:1:1-3:0.1-1.5 of oxymolybdenum dithiobis-carbamate, antimony dithiobis-carbamate, trimethylphenyl phosphate and bismuth sulfide.

[0012] The present application uses oxymolybdenum dithiobis-carbamate, antimony dithiobis-carbamate, trimethylphenyl phosphate and bismuth sulfide as the tribological property improver, and utilizes the activity of extreme pressure additive and organic molybdenum friction improver, under the action of friction, the friction surface is thermally decomposed to form a friction surface protection film mainly composed of MoS2, which improves the extreme pressure, wear resistance and low temperature tribological properties of the product, thereby greatly improving the friction-reducing and wear-resistant properties of the friction pair and prolonging its service life, ensuring the safe and stable operation of mechanical parts under various harsh conditions.

[0013] Preferably, the base oil is composed of ethyl silicone oil, diester base oil and PAO 4 synthetic base oil in a mass ratio of 1-5:30-50:20-40.

[0014] More preferably, the base oil is composed of ethyl silicone oil, diester base oil and PAO 4 synthetic base oil in a mass ratio of 2-5:35-45:30-35.

[0015] Preferably, the diester base oil is selected from one or both of neopentyl glycol di(2-ethylhexanoate) and pentaerythritol tetra(2-ethylhexanoate).

[0016] The ethyl silicone oil is obtained by hydrolytic condensation of ethyl ethoxy silane under the catalysis of hydrochloric acid to form polysiloxane, rearrangement of molecules, and then fractionation and post-treatment under vacuum, and has a freezing point lower than -70℃, a relative density of 0.95-1.05, and an open flash point greater than 265℃.

[0017] The diester base oil is obtained by esterification of a mixed acid of adipic acid and sebacic acid with a mixed alcohol of isooctanol and isononyl alcohol under the catalysis of an acid catalyst, and has a kinematic viscosity at 40℃ of 25.5-29.0mm 2 / s, a viscosity index greater than 130, and a pour point lower than -50℃.

[0018] The PAO 4 synthetic base oil has a kinematic viscosity at 100℃ of 3.5-4.5mm 2 / s, a viscosity index greater than 120, a pour point lower than -60℃, an oxidation stability (rotating bomb method, 150℃) not less than 380min, and an open flash point greater than 200℃.

[0019] The base oil of the present application is obtained by compounding the diester base oil and the PAO 4 synthetic base oil with the ethyl silicone oil, and fully utilizes the polarity of the ester base oil, which can be firmly adsorbed on the friction surface to form a layer of adhesive molecular oil film; the PAO 4 synthetic base oil and the ethyl silicone oil have excellent low-temperature performance, small temperature viscosity coefficient, excellent lubricity, oxidation resistance and low volatility. After compounding, the product can ensure flowability at low temperature, a certain thickness of the oil film at high temperature and good high-temperature oxidation resistance, and at the same time, good load-carrying capacity is imparted to the product, so as to meet the use requirements of the product in a wide temperature range and high load.

[0020] Preferably, the thickening agent is a lithium soap of a fatty acid, and the fatty acid is a monohydric hydroxy fatty acid, a monohydroxy stearic acid or a dihydric fatty acid.

[0021] Preferably, the monohydric hydroxy fatty acid is selected from one or more of 12-hydroxystearic acid, 9,10-dihydroxystearic acid, 6-hydroxyoctanoic acid and 10-hydroxydecanoic acid.

[0022] Preferably, the monobasic stearic acid is selected from one or more of palmitic acid, lauric acid and myristic acid.

[0023] Preferably, the dibasic fatty acid is selected from one or more of sebacic acid, azelaic acid and adipic acid.

[0024] More preferably, the thickening agent consists of lithium dodecanol stearate and lithium adipate in a mass ratio of 3-5:1.

[0025] The thickening agent of the present application uses lithium dodecanol stearate and lithium adipate, which can meet the high-temperature performance and excellent shear resistance of the product.

[0026] Preferably, the antioxidant is selected from one or more of zinc dialkyldithiophosphate, zinc alkyl dithiocarbamate, octylated phenyl-alpha-naphthylamine, diisooctyl diphenylamine and di-tert-butyl-p-cresol.

[0027] More preferably, the antioxidant consists of octylated phenyl-alpha-naphthylamine and diisooctyl diphenylamine in a mass ratio of 1:1-3.

[0028] The present application uses octylated phenyl-alpha-naphthylamine and diisooctyl diphenylamine as antioxidants. Hindered amines prevent or inhibit chain initiation and chain growth reactions by capturing peroxy radicals, thereby terminating the radical chain reaction, achieving the purpose of preventing oxidation, and effectively improving the oxidation stability and storage stability of the product.

[0029] Preferably, the adhesion agent consists of polyisobutylene and polymethyl methacrylate in a mass ratio of 1:0.5-1.5.

[0030] The present application uses high molecular polymers as adhesion agents. High molecular polymers can form a firm oil film, which tightly wraps the lubricating grease on the moving interface, avoiding the separation of lubricating grease under the scouring of high-speed air and water flow and the water resistance performance.

[0031] Preferably, the rust inhibitor is selected from one or two of benzotriazole and its derivatives, thiadiazole and its derivatives, barium dinonylnaphthalene sulfonate, alkenyl succinic acid, alkenyl succinate and its heterocyclics, polyol ester and sorbitan monooleate.

[0032] Preferably, the benzotriazole and its derivatives are selected from one or more of benzotriazole, methyl benzotriazole and carboxy benzotriazole.

[0033] The thiadiazole and its derivatives are selected from one or more of 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptobenzothiazole, 5-methyl-1,3,4-thiadiazole-2-thione and 2-amino-5-mercapto-1,3,4-thiadiazole.

[0034] The olefinic succinates and their heterocyclic analogs are selected from one or more of vinyl succinate, propenyl succinate, furanyl succinate, and pyridyl succinate.

[0035] The polyol esters are selected from one or more of pentaerythritol tetraester, trimethylolpropane triester, sorbitan polyesters, and glycerol triester.

[0036] More preferably, the rust-preventive agent is composed of sorbitan monooleate and benzotriazole and its derivatives in a mass ratio of 1:3-5.

[0037] Preferably, the composition comprises, in parts by mass, 60-85 parts of base oil, 5-15 parts of thickening agent, 2-6 parts of tribological property improver, 1-3 parts of antioxidant, 1-3 parts of adhesion agent, and 1-3 parts of rust-preventive agent.

[0038] More preferably, the composition comprises, in parts by mass, 70-80 parts of base oil, 10-15 parts of thickening agent, 3-5 parts of tribological property improver, 2-3 parts of antioxidant, 1-2 parts of adhesion agent, and 1-2 parts of rust-preventive agent.

[0039] The present application also provides a preparation method of the wide-temperature-range grease for helicopter transmission systems described above, comprising the following steps:

[0040] (1) mixing the thickening agent with part of the base oil, adding monohydrate lithium hydroxide, calcium hydroxide, and water, and reacting to obtain an intermediate product;

[0041] (2) mixing the intermediate product with the remaining base oil, cooling, and then adding the tribological property improver, antioxidant, adhesion agent, and rust-preventive agent, refluxing, and mixing uniformly to obtain the product.

[0042] Preferably, the temperature for adding monohydrate lithium hydroxide, calcium hydroxide, and water in step (1) is 50-80°C.

[0043] Preferably, the temperature for the reaction in step (1) is 150-160°C, and the reaction time is 30-40 min.

[0044] Preferably, the mixing in step (2) comprises heating the intermediate product to 200-210°C for 2-5 min, then mixing with the remaining base oil, homogenizing and dispersing, and cooling.

[0045] Preferably, the homogenizing and dispersing and cooling in step (2) are performed for 120-150 min.

[0046] Preferably, the temperature for the cooling in step (2) is 70-90°C, and the refluxing time is 120-150 min.

[0047] The application further provides application of the wide-temperature-range grease for a helicopter transmission system or the wide-temperature-range grease for a helicopter transmission system prepared by the preparation method in lubrication of a helicopter transmission system.

[0048] Compared with the prior art, the application has the following beneficial effects:

[0049] The wide-temperature-range grease for a helicopter transmission system has outstanding high-temperature antioxidant performance, excellent extreme-pressure and anti-wear performance and high-temperature performance, and excellent low-temperature starting and running torque, and can meet the use requirements of wide-temperature-range high-load of a helicopter transmission system lubricating grease product. DETAILED DESCRIPTION

[0050] It should be noted that the raw materials used in the application are all ordinary commercially available products.

[0051] Example 1

[0052] A wide-temperature-range grease for a helicopter transmission system is composed of 75 parts of base oil, 13 parts of thickening agent, 5 parts of tribological performance improver, 3 parts of antioxidant, 2 parts of adhesion agent and 2 parts of rust inhibitor by mass fraction;

[0053] The base oil is composed of ethyl silicone oil, neopentyl glycol di(2-ethylhexanoate) and PAO 4 synthetic base oil, and the parts of each component in the total formula composition are 5 parts, 40 parts and 30 parts by mass fraction respectively;

[0054] The thickening agent is composed of lithium dodecanol stearate and lithium adipate, and the parts of each component in the total formula composition are 10 parts and 3 parts by mass fraction respectively;

[0055] The tribological performance improver is composed of sulfur bidentate dibutyl dithiocarbamic acid molybdenum oxide, antimony bidentate dibutyl dithiocarbamic acid, trimethylphenyl phosphate and bismuth sulfide, and the parts of each component in the total formula composition are 2.25 parts, 0.75 parts, 1.5 parts and 0.5 parts by mass fraction respectively;

[0056] The antioxidant is composed of octylated phenyl-alpha-naphthylamine and diisooctyl diphenylamine, and the parts of each component in the total formula composition are 1.5 parts and 1.5 parts by mass fraction respectively;

[0057] The adhesion agent is composed of polyisobutylene and polymethyl methacrylate, and the parts of each component in the total formula composition are 1.0 parts and 1.0 parts by mass fraction respectively;

[0058] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, and the parts of each component in the total formula composition are 0.5 parts and 1.5 parts by mass fraction respectively.

[0059] The preparation method of the wide-temperature-range grease for helicopter transmission systems has the following steps:

[0060] S1, raw materials are prepared according to the proportions of various components.

[0061] S2, first, 1 / 3 of the base oil is taken into a reaction kettle, the thickening agent is added into the base oil for mixing and heating, when the temperature reaches 60 DEG C, lithium monohydrate hydroxide, calcium hydroxide and water are added, then the reaction kettle is closed and heated to 160 DEG C, and the saponification reaction is carried out for 40 min, and the intermediate product is obtained.

[0062] S3, after the saponification is completed, the reaction kettle is depressurized, the intermediate product generated in step S2 is quickly heated to 200 DEG C and kept for 5 min, then the materials in the reaction kettle and 1 / 3 of the base oil are mixed and transferred to an intermediate kettle, and the remaining base oil is added in the intermediate kettle during the cooling process;

[0063] S4, backflow shearing is carried out in the intermediate kettle, then homogenization, dispersion and cooling are carried out for 130 min, when the temperature of the mixture drops to 80 DEG C, the tribological performance improver, the antioxidant, the adhesion agent and the anti-rust agent are sequentially added, then backflow is carried out for 140 min, so that the various components are uniformly mixed, and grinding is carried out, and the wide-temperature-range grease for helicopter transmission systems is obtained.

[0064] Example 2

[0065] A wide-temperature-range grease for helicopter transmission systems is composed of 75 parts of base oil, 13 parts of thickening agent, 5 parts of tribological performance improver, 3 parts of antioxidant, 2 parts of adhesion agent and 2 parts of anti-rust agent by mass fraction;

[0066] The base oil is composed of ethyl silicone oil, pentaerythritol tetra(2-ethylhexanoate) and PAO 4 synthetic base oil, and the parts of each component in the total formula composition are 2 parts, 45 parts and 28 parts by mass fraction, respectively;

[0067] The thickening agent is composed of lithium dodecylhydroxystearate and lithium adipate, and the parts of each component in the total formula composition are 10.8 parts and 2.2 parts by mass fraction, respectively;

[0068] The tribological performance improver is composed of sulfur bismuthyl dithiocarbamic acid molybdenum, antimony dithiocarbamic acid, trimethylphenyl phosphate and bismuth sulfide, and the parts of each component in the total formula composition are 2.5 parts, 0.5 parts, 1.25 parts and 0.75 parts by mass fraction, respectively;

[0069] The antioxidant is composed of octylated phenyl-alpha-naphthylamine and diisooctyl diphenylamine, and the parts of each component in the total formula composition are 1.5 parts and 1.5 parts by mass fraction, respectively;

[0070] The adhesion agent is composed of polyisobutylene and polymethyl methacrylate, and the proportions of the components in the total formula are 1.0 parts and 1.0 parts respectively;

[0071] The rust inhibitor is composed of sorbitan monooleate and methyl benzotriazole, and the proportions of the components in the total formula are 0.5 parts and 1.5 parts respectively.

[0072] The preparation method of the wide-temperature-range grease for helicopter transmission systems comprises the following steps:

[0073] S1, prepare raw materials according to the proportions of the components.

[0074] S2, first, take 1 / 2 of the base oil and add it to the reaction kettle, take the thickening agent and mix it with the base oil and heat, when the temperature reaches 50℃, add lithium hydroxide monohydrate, calcium hydroxide and water, then seal the reaction kettle and heat it to 150℃, carry out saponification reaction, the reaction time is 30min, and the intermediate product is obtained.

[0075] S3, after the saponification is completed, the reaction kettle is depressurized, the intermediate product generated in step S2 is quickly heated to 210℃ and kept for 2min, then the materials in the reaction kettle are mixed with 1 / 5 of the base oil and transferred to the intermediate kettle, and the remaining base oil is added to the intermediate kettle during the cooling process;

[0076] S4, carry out reflux shearing in the intermediate kettle, then homogenize, disperse and cool, the time is 150min, when the temperature of the mixture drops to 70℃, then add the tribological performance improver, the antioxidant, the adhesion agent and the rust inhibitor in sequence, then reflux for 120min, so that the components are uniformly mixed, and the wide-temperature-range grease for helicopter transmission systems is obtained.

[0077] Example 3

[0078] A wide-temperature-range grease for helicopter transmission systems, composed of 75 parts of base oil, 13 parts of thickening agent, 5 parts of tribological performance improver, 3 parts of antioxidant, 2 parts of adhesion agent and 2 parts of rust inhibitor;

[0079] The base oil is composed of ethyl silicone oil, neopentyl glycol di(2-ethylhexanoate) and PAO 4 synthetic base oil, and the proportions of the components in the total formula are 5 parts, 40 parts and 30 parts respectively;

[0080] The thickening agent is composed of lithium dodecanol stearate and lithium adipate, and the proportions of the components in the total formula are 10 parts and 3 parts respectively;

[0081] The tribological performance improver is composed of sulfur dibutyl dithiocarbamic acid oxygen molybdenum, antimony dibutyl dithiocarbamic acid, phosphoric acid trimethylphenol ester and bismuth sulfide, and the proportions of the components in the total formula are 2.25 parts, 0.75 parts, 1.5 parts and 0.5 parts respectively;

[0082] The antioxidant is composed of octylated phenyl-alpha-naphthylamine and diisooctyl diphenylamine, and the proportions of the components in the total formula are 0.75 parts and 2.25 parts respectively;

[0083] The adhesion agent is composed of polyisobutylene and polymethyl methacrylate, and the proportions of the components in the total formula are 0.8 parts and 1.2 parts respectively;

[0084] The rust inhibitor is composed of sorbitan monooleate and carboxy benzotriazole, and the proportions of the components in the total formula are 0.4 parts and 1.6 parts respectively.

[0085] The preparation method of the wide-temperature-range grease for a helicopter transmission system comprises the following steps:

[0086] S1, preparing raw materials according to the proportions of the components.

[0087] S2, first, 1 / 2 of the base oil is taken into a reaction kettle, the thickening agent is added into the base oil for mixing and heating, and when the temperature reaches 50℃, lithium hydroxide monohydrate, calcium hydroxide and water are added, then the reaction kettle is closed and heated to 160℃, a saponification reaction is carried out, the reaction time is 40 min, and an intermediate product is obtained.

[0088] S3, after the saponification is completed, the reaction kettle is depressurized, the intermediate product generated in step S2 is quickly heated to 210℃ and kept for 2 min, then the materials in the reaction kettle and 1 / 3 of the base oil are mixed and transferred to an intermediate kettle, and the remaining base oil is added to the intermediate kettle during the cooling process;

[0089] S4, backflow shearing is carried out in the intermediate kettle, then homogenization, dispersion and cooling are carried out, the time is 120 min, when the temperature of the mixture drops to 90℃, the tribological performance improver, the antioxidant, the adhesion agent and the rust inhibitor are sequentially added, then backflow is carried out for 140 min, so that the components are uniformly mixed, and grinding is carried out, thereby obtaining the wide-temperature-range grease for a helicopter transmission system.

[0090] Example 4

[0091] A wide-temperature-range grease for a helicopter transmission system is composed of 75 parts of base oil, 13 parts of thickening agent, 5 parts of tribological performance improver, 3 parts of antioxidant, 2 parts of adhesion agent and 2 parts of rust inhibitor.

[0092] The base oil is composed of ethyl silicone oil, pentaerythritol tetra(2-ethylhexanoic acid) ester and PAO 4 synthetic base oil, and by mass parts, each component accounts for 5 parts, 40 parts and 30 parts of the total formula, respectively.

[0093] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 10 parts and 3 parts of the total formulation, respectively.

[0094] The tribological performance improver is composed of molybdenum thiodibutyldithiocarbamate, antimony dibutyldithiocarbamate, tricresyl phosphate and bismuth sulfide, and the proportions of each component in the total formula by weight are 3 parts, 0.75 parts, 1.0 parts and 0.25 parts respectively.

[0095] The antioxidant is composed of octylphenyl-α-naphthylamine and diisooctyldiphenylamine, with each component accounting for 1.5 parts and 1.5 parts of the total formulation by mass, respectively.

[0096] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.0 part and 1.0 part of the total formulation by weight, respectively.

[0097] The rust inhibitor is composed of sorbitan monooleate and carboxybenzotriazole, with each component accounting for 0.5 parts and 1.2 parts of the total formula by mass.

[0098] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above is the same as in Example 1.

[0099] Example 5

[0100] A wide-temperature-range grease for helicopter transmission systems, by weight, consists of 60 parts base oil, 15 parts thickener, 6 parts tribological property improver, 1 part antioxidant, 3 parts adhesive and 3 parts rust inhibitor.

[0101] The base oil is composed of ethyl silicone oil, neopentyl glycol di(2-ethylhexanoate) ester and PAO 4 synthetic base oil, and by mass parts, each component accounts for 1 part, 30 parts and 29 parts of the total formula, respectively.

[0102] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 12 parts and 3 parts of the total formulation, respectively.

[0103] The tribological performance improver is composed of molybdenum thiodibutyldithiocarbamate, antimony dibutyldithiocarbamate, tricresyl phosphate and bismuth sulfide, and the proportions of each component in the total formula by weight are 3 parts, 1 part, 1.0 part and 1.0 part, respectively.

[0104] The antioxidant is octylphenyl-α-naphthylamine, which accounts for 1.0 part of the total formula by weight.

[0105] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.5 parts by weight of the total formulation.

[0106] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, with each component accounting for 1 part and 2 parts of the total formula by mass.

[0107] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above includes the following steps:

[0108] S1. Prepare the raw materials according to the proportions of each component.

[0109] S2. First, add 1 / 3 of the base oil to the reaction vessel, add the thickener to the base oil, mix and heat. When the temperature reaches 60°C, add lithium hydroxide monohydrate, calcium hydroxide and water. Then, seal the reaction vessel and heat it to 155°C to carry out the saponification reaction. The reaction time is 35 minutes to obtain the intermediate product.

[0110] S3. After saponification, depressurize the reactor, rapidly heat the intermediate product generated in step S2 to 205°C and hold for 3 minutes, then mix the material in the reactor with 1 / 3 of the base oil and transfer it to the intermediate reactor. During the cooling process, add the remaining base oil to the intermediate reactor.

[0111] S4. Reflux shearing is performed in an intermediate reactor, followed by homogenization, dispersion, and cooling for 140 minutes. When the temperature of the mixture drops to 85°C, tribological performance improver, antioxidant, adhesive, and rust inhibitor are added in sequence. Then, reflux is performed for 130 minutes to ensure that all components are mixed evenly. After grinding, a wide temperature range grease for helicopter transmission systems is obtained.

[0112] Comparative Example 1

[0113] Same as Example 1, except that the base oil does not contain ethyl silicone oil.

[0114] A wide-temperature-range grease for helicopter transmission systems, by weight, consists of 75 parts base oil, 13 parts thickener, 5 parts tribological property improver, 3 parts antioxidant, 2 parts adhesive and 2 parts rust inhibitor.

[0115] The base oil is composed of neopentyl glycol di(2-ethylhexanoate) ester and PAO 4 synthetic base oil, with each component accounting for 45 parts and 30 parts of the total formula by mass.

[0116] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 10 parts and 3 parts of the total formulation, respectively.

[0117] The tribological performance improver is composed of molybdenum thiodibutyl dithiocarbamate, antimony dibutyl dithiocarbamate, tricresyl phosphate and bismuth sulfide, and the proportions of each component in the total formulation by weight are 2.25 parts, 0.75 parts, 1.5 parts and 0.5 parts, respectively.

[0118] The antioxidant is composed of octylphenyl-α-naphthylamine and diisooctyldiphenylamine, with each component accounting for 1.5 parts and 1.5 parts of the total formulation by mass, respectively.

[0119] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.0 part and 1.0 part of the total formulation by weight, respectively.

[0120] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, with each component accounting for 0.5 parts and 1.5 parts of the total formula by mass.

[0121] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above is the same as in Example 1.

[0122] Comparative Example 2

[0123] Same as Example 1, except that the tribological property improver does not contain antimony dibutyldithiocarbamate and bismuth sulfide.

[0124] A wide-temperature-range grease for helicopter transmission systems, by weight, consists of 75 parts base oil, 13 parts thickener, 5 parts tribological property improver, 3 parts antioxidant, 2 parts adhesive and 2 parts rust inhibitor.

[0125] The base oil is composed of ethyl silicone oil, neopentyl glycol di(2-ethylhexanoate) ester and PAO 4 synthetic base oil, and by mass parts, each component accounts for 5 parts, 40 parts and 30 parts of the total formula, respectively.

[0126] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 10 parts and 3 parts of the total formulation, respectively.

[0127] The tribological performance improver is composed of molybdenum thiodibutyl dithiocarbamate and tricresyl phosphate, with each component accounting for 3.5 parts and 1.5 parts of the total formulation by mass.

[0128] The antioxidant is composed of octylphenyl-α-naphthylamine and diisooctyldiphenylamine, with each component accounting for 1.5 parts and 1.5 parts of the total formulation by mass, respectively.

[0129] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.0 part and 1.0 part of the total formulation by weight, respectively.

[0130] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, with each component accounting for 0.5 parts and 1.5 parts of the total formula by mass.

[0131] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above is the same as in Example 1.

[0132] Comparative Example 3

[0133] Same as Example 1, except that the thickener group distribution ratio is different.

[0134] A wide-temperature-range grease for helicopter transmission systems, by weight, consists of 75 parts base oil, 13 parts thickener, 5 parts tribological property improver, 3 parts antioxidant, 2 parts adhesive and 2 parts rust inhibitor.

[0135] The base oil is composed of ethyl silicone oil, neopentyl glycol di(2-ethylhexanoate) ester and PAO 4 synthetic base oil, and by mass parts, each component accounts for 5 parts, 40 parts and 30 parts of the total formula, respectively.

[0136] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 12 parts and 1 part of the total formulation, respectively.

[0137] The tribological performance improver is composed of molybdenum thiodibutyl dithiocarbamate, antimony dibutyl dithiocarbamate, tricresyl phosphate and bismuth sulfide, and the proportions of each component in the total formulation by weight are 2.25 parts, 0.75 parts, 1.5 parts and 0.5 parts, respectively.

[0138] The antioxidant is composed of octylphenyl-α-naphthylamine and diisooctyldiphenylamine, with each component accounting for 1.5 parts and 1.5 parts of the total formulation by mass, respectively.

[0139] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.0 part and 1.0 part of the total formulation by weight, respectively.

[0140] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, with each component accounting for 0.5 parts and 1.5 parts of the total formula by mass.

[0141] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above is the same as in Example 1.

[0142] Comparative Example 4

[0143] Same as Example 1, except that the antioxidant does not contain diisooctyldiphenylamine.

[0144] A wide-temperature-range grease for helicopter transmission systems, by weight, consists of 75 parts base oil, 13 parts thickener, 5 parts tribological property improver, 3 parts antioxidant, 2 parts adhesive and 2 parts rust inhibitor.

[0145] The base oil is composed of ethyl silicone oil, neopentyl glycol di(2-ethylhexanoate) ester and PAO 4 synthetic base oil, and by mass parts, each component accounts for 5 parts, 40 parts and 30 parts of the total formula, respectively.

[0146] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 10 parts and 3 parts of the total formulation, respectively.

[0147] The tribological performance improver is composed of molybdenum thiodibutyl dithiocarbamate, antimony dibutyl dithiocarbamate, tricresyl phosphate and bismuth sulfide, and the proportions of each component in the total formulation by weight are 2.25 parts, 0.75 parts, 1.5 parts and 0.5 parts, respectively.

[0148] The antioxidant is octylphenyl-α-naphthylamine, which accounts for 3.0 parts by mass of the total formulation.

[0149] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.0 part and 1.0 part of the total formulation by weight, respectively.

[0150] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, with each component accounting for 0.5 parts and 1.5 parts of the total formula by mass.

[0151] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above is the same as in Example 1.

[0152] Comparative Example 5

[0153] Same as Example 1, except that the ethyl silicone oil in the base oil is replaced with PAO 6 synthetic base oil.

[0154] A wide-temperature-range grease for helicopter transmission systems, by weight, consists of 75 parts base oil, 13 parts thickener, 5 parts tribological property improver, 3 parts antioxidant, 2 parts adhesive and 2 parts rust inhibitor.

[0155] The base oil is composed of PAO 6 synthetic base oil, neopentyl glycol di(2-ethylhexanoate) ester and PAO 4 synthetic base oil, and by mass parts, each component accounts for 5 parts, 40 parts and 30 parts of the total formula, respectively.

[0156] The thickener is composed of lithium dodecyl stearate and lithium adipate, and by mass percentage, each component accounts for 10 parts and 3 parts of the total formulation, respectively.

[0157] The tribological performance improver is composed of molybdenum thiodibutyl dithiocarbamate, antimony dibutyl dithiocarbamate, tricresyl phosphate and bismuth sulfide, and the proportions of each component in the total formulation by weight are 2.25 parts, 0.75 parts, 1.5 parts and 0.5 parts, respectively.

[0158] The antioxidant is composed of octylphenyl-α-naphthylamine and diisooctyldiphenylamine, with each component accounting for 1.5 parts and 1.5 parts of the total formulation by mass, respectively.

[0159] The adhesive is composed of polyisobutylene and polymethyl methacrylate, with each component accounting for 1.0 part and 1.0 part of the total formulation by weight, respectively.

[0160] The rust inhibitor is composed of sorbitan monooleate and benzotriazole, with each component accounting for 0.5 parts and 1.5 parts of the total formula by mass.

[0161] The preparation method of the wide-temperature-range grease for the helicopter transmission system described above is the same as in Example 1.

[0162] Test Example 1

[0163] The wide-temperature-range lubricating greases for helicopter transmission systems prepared in Examples 1-5 and Comparative Examples 1-5 were respectively tested for basic physicochemical properties according to the evaluation items of GJB942-90—"Lubricating Greases for Aircraft, Instruments, Gears and Transmission Screws". The results are shown in Tables 1-2.

[0164] Table 1. Test data of wide-temperature-range greases for helicopter transmission systems prepared in Examples 1-5.

[0165]

[0166] Table 2. Test data of wide-temperature-range greases for helicopter transmission systems prepared in Comparative Examples 1-5

[0167]

[0168]

[0169] As can be seen from the test data of Examples 1-5 and Comparative Examples 1-5, the wide-temperature-range grease composition for helicopter transmission systems of the present invention has the following advantages:

[0170] (1) Outstanding high and low temperature performance, with a low temperature of -73℃ and a long-term high temperature of up to 121℃, suitable for lubrication of aircraft gears, transmission screws and instrument and electronic equipment in the range of -73℃ to 120℃.

[0171] (2) Excellent low-temperature starting and running torque, meeting the low-temperature starting and lubrication requirements of high-precision helicopter transmission systems with low starting power.

[0172] (3) Excellent lubrication and friction performance, which not only has a high load-bearing capacity, but also effectively reduces the friction torque of system components.

[0173] It meets the technical specifications of the national military standard GJB 942-90—"Lubricating Grease for Aircraft, Instruments, Gears and Transmission Screws".

[0174] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A wide-temperature-range lubricating grease for a helicopter transmission system, characterized in that, The composition comprises the following components: base oil, thickening agent, tribological performance improver, antioxidant, adhesion agent and rust inhibitor, the tribological performance improver is composed of mass ratio of 3-5:1:1-3:0.1-1.5 of sulfur bismuth dithio carbamic acid oxymolybdenum, antimony dithio carbamate, trimethyl phenol phosphate and bismuth sulfide.

2. The wide temperature range grease for helicopter transmission systems according to claim 1, characterized in that, The base oil is composed of mass ratio of 1-5:30-50:20-40 of ethyl silicone oil, double ester base oil and PAO 4 synthetic base oil.

3. The wide temperature range grease for helicopter transmission systems according to claim 2, characterized in that, The double ester base oil is selected from one or two of neopentyl glycol di(2-ethyl hexanoate) and pentaerythritol tetra(2-ethyl hexanoate).

4. The wide temperature range grease for helicopter transmission systems according to claim 1, characterized in that, The thickening agent is lithium soap of fatty acid, the fatty acid is monohydric hydroxy fatty acid, monohydric stearic acid or dibasic fatty acid.

5. The wide temperature range grease for helicopter transmission systems according to claim 4, characterized in that, The monohydric hydroxy fatty acid is selected from one or more of 12-hydroxystearic acid, 9,10-dihydroxystearic acid, 6-hydroxyoctanoic acid and 10-hydroxydecanoic acid, the monohydric stearic acid is selected from one or more of palmitic acid, lauric acid and myristic acid, and the dibasic fatty acid is selected from one or more of sebacic acid, azelaic acid and adipic acid.

6. The wide temperature range grease for helicopter transmission systems according to claim 5, characterized in that, The thickening agent is composed of mass ratio of 3-5:1 of lithium dodecanol stearate and lithium adipate.

7. The wide temperature range grease for helicopter transmission systems according to claim 1, characterized in that, The antioxidant is selected from one or more of zinc dialkyldithiophosphate, zinc alkyl dithio carbamate, octylated phenyl-alpha-naphthylamine, diisooctyl diphenylamine and di-tert-butyl-p-cresol.

8. The wide-temperature-range grease for helicopter transmission systems according to claim 7, characterized in that, The antioxidant is composed of mass ratio of 1:1-3 of octylated phenyl-alpha-naphthylamine and diisooctyl diphenylamine.

9. The wide temperature range grease for helicopter transmission systems according to claim 1, characterized in that, The adhesion agent is composed of mass ratio of 1:0.5-1.5 of polyisobutylene and polymethyl methacrylate.

10. The wide temperature range grease for helicopter transmission systems according to claim 1, characterized in that, The rust inhibitor is selected from one or two of benzotriazole and its derivatives, thiazole and its derivatives, barium dinonylnaphthalene sulfonate, alkenyl succinic acid, alkenyl succinate and its heterocyclic class, polyol fat and sorbitan monooleate.

11. The wide temperature range grease for helicopter transmission systems according to claim 10, characterized in that, The benzotriazole and its derivatives are selected from one or more of benzotriazole, methyl benzotriazole and carboxy benzotriazole, the thiazole and its derivatives are selected from one or more of 2,5-dimercapto-1,3,4-thiazole, 2-mercaptobenzothiazole, 5-methyl-1,3,4-thiazole-2-thione and 2-amino-5-mercapto-1,3,4-thiazole, the alkenyl succinate and its heterocyclic class are selected from one or more of vinyl succinate, propenyl succinate, furan succinate and pyridyl succinate, and the polyol fat is selected from one or more of pentaerythritol tetraester, trimethylolpropane triester, sorbitan polyester and glycerol triester.

12. The wide temperature range grease for helicopter transmission systems according to claim 11, characterized in that, The rust inhibitor is composed of mass ratio of 1:2-5 of sorbitan monooleate and benzotriazole and its derivatives.

13. The wide temperature range grease for helicopter transmission systems according to claim 1, characterized in that, The composition comprises the following components by mass fraction: base oil 60-85 parts, thickening agent 5-15 parts, tribological performance improver 2-6 parts, antioxidant 1-3 parts, adhesion agent 1-3 parts and rust inhibitor 1-3 parts.

14. A process for the preparation of a wide temperature range grease for helicopter transmission systems according to any one of claims 1 to 13, characterized in that, The composition comprises the following steps: (1) mixing the thickening agent with part of the base oil, adding lithium hydroxide monohydrate, calcium hydroxide and water, reacting to obtain an intermediate product; (2) mixing the intermediate product with the remaining base oil, cooling, adding a friction performance improver, an antioxidant, an adhesion agent and an antirust agent, refluxing, mixing and homogenizing to obtain the product.

15. The preparation method according to claim 14, characterized in that, The temperature for adding lithium hydroxide monohydrate, calcium hydroxide and water in step (1) is 50-80℃, the temperature for the reaction is 150-160℃, and the reaction time is 30-40 min.

16. The method of claim 14, wherein, The mixing process in step (2) includes heating the intermediate product to 200-210℃ for 2-5 min, mixing with the remaining base oil, homogenizing and dispersing, cooling, the cooling temperature is 70-90℃, and the refluxing time is 120-150 min.

17. The preparation method according to claim 16, characterized in that, The homogenizing and dispersing cooling time is 120-150 min.

18. The use of a wide-temperature-range grease according to any one of claims 1-13 or prepared according to the method of any one of claims 14-17 in the lubrication of a helicopter transmission system.

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