A kind of lubricating grease for automobile constant velocity universal joint

Abstract

The invention discloses a lubricating grease for a constant velocity universal joint of an automobile. The lubricating grease is prepared by mixing and stirring a modified base oil and lubricating particles, adding 12-hydroxystearic acid, and then sequentially reacting a lithium hydroxide aqueous solution and sebacic acid. When the lubricating grease is used, nitrogen atoms in imidazole rings on the lubricating particles can generate coordination bonds with empty orbits on the metal surface of the universal joint, thereby allowing the lubricating particles to be adsorbed on the surface thereof. Both graphene and molybdenum disulfide are two-dimensional layer structures, contain weak van der Waals forces and strong intra-layer covalent bonds, and are easy to slide, thereby reducing the friction coefficient. Meanwhile, a cage-type silsesquioxane cavity is contained between a graphene matrix and a molybdenum disulfide matrix, so that the graphene matrix and the molybdenum disulfide matrix can also slide in a small range, thereby further improving the lubrication performance. Meanwhile, the modified base oil has high viscosity and has lubricity and degradability, thereby further improving the lubrication effect.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating grease preparation, in particular to lubricating grease for automobile constant velocity universal joints. Background Art

[0002] The automobile industry is developing rapidly and plays an important role in many aspects such as daily life, agriculture and transportation. In the process of using the car, friction and wear of the parts are inevitable, which in turn affects the life of the car. Adding lubricants is one of the most widely used methods to improve the friction and wear resistance of the parts. The constant velocity joint, referred to as CVJ, is used to connect two rotating shafts with an angle or a change in relative position between the shafts, and make the two shafts transmit power at the same angular velocity. It can overcome the problem of non-constant velocity in ordinary cross-axis universal joints and is particularly suitable for the use of steering drive axles. The axial force is easy to generate when the car is running, causing vibration and noise when walking. The body rolls, and the friction between the roller spherical surface and the track has a great influence. Therefore, the friction coefficient of the grease is required to be small. Summary of the invention

[0003] The purpose of the present invention is to provide a lubricating grease for automobile constant velocity joints, which solves the problem that the existing lubricating grease has poor lubrication effect and may cause friction surface damage.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A lubricating grease for automobile constant velocity joints is prepared by the following steps:

[0006] The modified base oil and lubricating particles are mixed evenly, stirred at a speed of 200-300 r / min and a temperature of 85-90°C, and 12-hydroxystearic acid is added. After stirring for 30-40 minutes, a lithium hydroxide aqueous solution is added and the temperature is raised to 100-105°C, and the reaction is carried out for 1-1.5 hours. Sebacic acid is added and the temperature is raised to 120-125°C, and the reaction is carried out for 30-40 minutes. The temperature is raised to 200-210°C, and the heat treatment is carried out for 10-15 minutes to obtain a grease for automobile constant velocity joints.

[0007] Furthermore, the mass ratio of the modified base oil, 12-hydroxystearic acid, lithium hydroxide and sebacic acid is 100:7.9:0.9:2.11, and the amount of the lubricating particles is 0.1-0.3% of the mass of the base oil.

[0008] Furthermore, the lubricating particles are prepared by the following steps:

[0009] Step A1: dispersing graphene oxide in THF, adding dicyclohexylcarbodiimide and KH550, stirring for 3-5 hours at a speed of 200-300 r / min and a temperature of 20-25° C., filtering and removing the filtrate, dispersing the substrate in dimethyl sulfoxide, adding 3-mercaptopropyltrimethoxysilane, stirring for 10-15 hours at a speed of 300-500 r / min and a temperature of 55-65° C., cooling to room temperature, adding ammonium fluoride and continuing to stir for 20-25 hours, and then aging for 7-9 days at a temperature of 80-85° C. to obtain modified graphene;

[0010] Step A2: ammonium molybdate, thiourea and deionized water are mixed evenly, and the mixture is subjected to a hydrothermal reaction at a temperature of 200-210° C. for 20-25 hours, and then the mixture is dried and dispersed in hexanol, and deionized water is added and mixed evenly. KH570 is added under stirring at a speed of 200-300 r / min and a temperature of 80-85° C., and the mixture is stirred for 5-7 hours, and the filtrate is removed by filtering, and the filter cake is washed with deionized water and dried to obtain functionalized molybdenum disulfide;

[0011] Step A3: Acryloyl chloride, imidazole, N, N-diisopropylethylamine and chloroform are mixed, and the mixture is reacted for 3-5 hours at a speed of 200-300 r / min and a temperature of 5-10°C to obtain intermediate 1. The modified graphene and functionalized molybdenum disulfide are dispersed in tetrahydrofuran, and 2,2-dimethoxy-2-phenylacetophenone is added. The mixture is reacted for 30-40 minutes at a speed of 150-200 r / min and irradiated with a 365nm ultraviolet lamp. Then, intermediate 1 is added, the reaction is continued for 30-40 minutes, and the filtrate is removed by filtration to obtain lubricating particles.

[0012] Furthermore, the amount ratio of graphene oxide, dicyclohexylcarbodiimide and KH550 described in step A1 is 5.5g:0.4g:6mL, and the amount ratio of substrate, 3-mercaptopropyltrimethoxysilane and ammonium fluoride is 2g:3mL:0.3g.

[0013] Furthermore, the usage ratio of ammonium molybdate, thiourea and deionized water in step A2 is 2.47 g:2.284 g:70 mL, and the usage ratio of substrate, hexanol, deionized water and KH570 is 0.1 g:20 mL:5 mL:1 g.

[0014] Furthermore, the molar ratio of acryloyl chloride, imidazole and N,N-diisopropylethylamine in step A3 is 1:1:1.1, the mass ratio of modified graphene, functionalized molybdenum disulfide and intermediate 1 is 3:0.5:1, and the amount of 2,2-dimethoxy-2-phenylacetophenone is 3-5% of the mass of modified graphene.

[0015] Further, the modified base oil is prepared by the following steps:

[0016] Step B1: Castor oil and methyl ricinoleate are mixed, nitrogen is introduced for protection, aluminum chloride is added, and the reaction is carried out for 3-5 hours at a temperature of 120-125° C., deionized water is added for quenching and the pH is adjusted to neutral, the water layer is removed, palladium carbon and n-hexane are added, nitrogen is introduced to exhaust the air, and hydrogen is introduced, and the reaction is carried out for 2-4 hours at a speed of 300-500 r / min and a temperature of 250-255° C. to obtain a base oil;

[0017] Step B2: Mix the base oil and methyl laurate, stir for 10-15 minutes at a speed of 600-800 r / min and a temperature of 80-90° C., add concentrated sulfuric acid, continue stirring for 5-7 hours, add deionized water to wash until the pH is neutral, remove the water layer, and obtain a modified base oil.

[0018] Furthermore, the amount ratio of castor oil, methyl ricinoleate, aluminum chloride, palladium carbon and n-hexane in step B1 is 2g:8g:0.5g:0.2g:80mL.

[0019] Furthermore, the molar ratio of the hydroxyl group on the base oil and methyl laurate in step B2 is 1:1.2, and the amount of concentrated sulfuric acid used is 2-3% of the total mass of the base oil and methyl laurate.

[0020] Beneficial effects of the invention: The grease for automobile constant velocity universal joint disclosed by the invention is prepared by mixing and stirring a modified base oil and lubricating particles, adding 12-hydroxystearic acid, and then reacting a lithium hydroxide aqueous solution and sebacic acid in sequence. The modified base oil uses castor oil and methyl ricinoleate as raw materials, polymerizes double bonds on castor oil and methyl ricinoleate under the action of aluminum chloride, and then hydrogenates the polymer under the action of palladium carbon to obtain the base oil. The base oil is esterified with methyl laurate to obtain the modified base oil. The lubricating particles are treated with KH550 using graphene oxide as a raw material, so that the carboxyl groups on the graphene oxide and the amino groups on the KH550 undergo dehydration condensation, and then 3-mercaptopropyltrimethoxysilane is added to undergo condensation through a sol-gel method, so that the siloxane groups on the surface undergo condensation with 3-mercaptopropyltrimethoxysilane to form a cage-type silsesquioxane structure to obtain modified graphene, and ammonium molybdate, thiourea and deionized water are hydrothermally reacted to obtain nano-molybdenum disulfide, and then KH570 is added for surface treatment to obtain nano-molybdenum disulfide. The double bond is grafted on the surface, acryloyl chloride is reacted with imidazole, so that the acyl chloride group and the active hydrogen atom on the imidazole undergo amidation reaction to obtain intermediate 1, and the modified graphene and functionalized molybdenum disulfide are irradiated with ultraviolet light, and part of the thiol groups on the surface of the modified graphene are grafted with the double bonds on the functionalized molybdenum disulfide, and the remaining thiol groups are grafted with the double bonds on the intermediate 1 to obtain lubricating particles. When the grease is used, the nitrogen atoms in the imidazole rings on the lubricating particles can form coordination bonds with the empty orbitals on the metal surface of the universal joint, and then The lubricating particles are adsorbed on its surface, and both graphene and molybdenum disulfide are two-dimensional layer structures with weak van der Waals forces and strong intralayer covalent bonds, which are easy to slide, thereby reducing the friction coefficient. At the same time, there is a cage-type silsesquioxane cavity between the graphene matrix and the molybdenum disulfide matrix, which allows the graphene matrix and the molybdenum disulfide matrix to slide in a small range, further improving the lubrication performance. At the same time, the modified base oil has a high viscosity and is lubricious and degradable, which further improves the lubrication effect. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0022] A lubricating grease for automobile constant velocity joints is prepared by the following steps:

[0023] The modified base oil and lubricating particles are mixed evenly, stirred at a speed of 200 r / min and a temperature of 85°C and 12-hydroxystearic acid is added. After stirring for 30 minutes, a lithium hydroxide aqueous solution is added and the temperature is raised to 100°C, and the reaction is carried out for 1 hour. Sebacic acid is added and the temperature is raised to 120°C, and the reaction is carried out for 30 minutes. The temperature is raised to 200°C and the heat is kept for 10 minutes to obtain grease for automobile constant velocity joints.

[0024] The mass ratio of the modified base oil, 12-hydroxystearic acid, lithium hydroxide and sebacic acid is 100:7.9:0.9:2.11, and the amount of the lubricating particles is 0.1% of the mass of the base oil.

[0025] The lubricating particles are prepared by the following steps:

[0026] Step A1: dispersing graphene oxide in THF, adding dicyclohexylcarbodiimide and KH550, stirring for 3 hours at a speed of 200 r / min and a temperature of 20°C, filtering and removing the filtrate, dispersing the substrate in dimethyl sulfoxide, adding 3-mercaptopropyltrimethoxysilane, stirring for 10 hours at a speed of 300 r / min and a temperature of 55°C, cooling to room temperature, adding ammonium fluoride and continuing to stir for 20 hours, and then aging for 7 days at a temperature of 80°C to obtain modified graphene;

[0027] Step A2: ammonium molybdate, thiourea and deionized water are mixed evenly, and hydrothermally reacted at a temperature of 200° C. for 20 hours, then dried and the substrate is dispersed in hexanol, deionized water is added and mixed evenly, and KH570 is added under stirring at a speed of 200 r / min and a temperature of 80° C. After stirring for 5 hours, the filtrate is filtered to remove the filtrate, and the filter cake is washed with deionized water and dried to obtain functionalized molybdenum disulfide;

[0028] Step A3: Acryloyl chloride, imidazole, N,N-diisopropylethylamine and chloroform are mixed, and the reaction is carried out at a speed of 200 r / min and a temperature of 5°C for 3 hours to obtain intermediate 1. The modified graphene and functionalized molybdenum disulfide are dispersed in tetrahydrofuran, 2,2-dimethoxy-2-phenylacetophenone is added, and the reaction is carried out at a speed of 150 r / min and irradiation with a 365nm ultraviolet lamp for 30-40 minutes. Then, intermediate 1 is added, the reaction is continued for 30 minutes, and the filtrate is filtered to obtain lubricating particles.

[0029] The amount ratio of graphene oxide, dicyclohexylcarbodiimide and KH550 described in step A1 is 5.5g:0.4g:6mL, and the amount ratio of substrate, 3-mercaptopropyltrimethoxysilane and ammonium fluoride is 2g:3mL:0.3g.

[0030] The amount ratio of ammonium molybdate, thiourea and deionized water in step A2 is 2.47 g:2.284 g:70 mL, and the amount ratio of substrate, hexanol, deionized water and KH570 is 0.1 g:20 mL:5 mL:1 g.

[0031] The molar ratio of acryloyl chloride, imidazole and N,N-diisopropylethylamine described in step A3 is 1:1:1.1, the mass ratio of modified graphene, functionalized molybdenum disulfide and intermediate 1 is 3:0.5:1, and the amount of 2,2-dimethoxy-2-phenylacetophenone is 3% of the mass of modified graphene.

[0032] The modified base oil is prepared by the following steps:

[0033] Step B1: Castor oil and methyl ricinoleate are mixed, nitrogen is introduced for protection, aluminum chloride is added, and the reaction is carried out at a temperature of 120° C. for 3 hours, deionized water is added for quenching and the pH is adjusted to neutral, the water layer is removed, palladium carbon and n-hexane are added, nitrogen is introduced to exhaust the air, and hydrogen is introduced, and the reaction is carried out at a speed of 300 r / min and a temperature of 250° C. for 2 hours to obtain a base oil;

[0034] Step B2: Mix the base oil and methyl laurate, stir for 10 minutes at a speed of 600 r / min and a temperature of 80°C, add concentrated sulfuric acid, continue stirring for 5 hours, add deionized water to wash until the pH is neutral, remove the water layer, and obtain a modified base oil.

[0035] The amount ratio of castor oil, methyl ricinoleate, aluminum chloride, palladium carbon and n-hexane described in step B1 is 2g:8g:0.5g:0.2g:80mL.

[0036] The molar ratio of the hydroxyl group on the base oil and methyl laurate in step B2 is 1:1.2, and the amount of concentrated sulfuric acid used is 2% of the total mass of the base oil and methyl laurate. Example 2

[0037] A lubricating grease for automobile constant velocity joints is prepared by the following steps:

[0038] The modified base oil and lubricating particles are mixed evenly, stirred at a speed of 200 r / min and a temperature of 88°C and 12-hydroxystearic acid is added. After stirring for 35 minutes, a lithium hydroxide aqueous solution is added and the temperature is raised to 103°C, and the reaction is carried out for 1.3 hours. Sebacic acid is added and the temperature is raised to 123°C, and the reaction is carried out for 35 minutes. The temperature is raised to 205°C and the heat is kept for 13 minutes to obtain grease for automobile constant velocity joints.

[0039] The mass ratio of the modified base oil, 12-hydroxystearic acid, lithium hydroxide and sebacic acid is 100:7.9:0.9:2.11, and the amount of the lubricating particles is 0.2% of the mass of the base oil.

[0040] The lubricating particles are prepared by the following steps:

[0041] Step A1: dispersing graphene oxide in THF, adding dicyclohexylcarbodiimide and KH550, stirring for 4 hours at a speed of 200 r / min and a temperature of 23° C., filtering and removing the filtrate, dispersing the substrate in dimethyl sulfoxide, adding 3-mercaptopropyltrimethoxysilane, stirring for 13 hours at a speed of 500 r / min and a temperature of 60° C., cooling to room temperature, adding ammonium fluoride and continuing to stir for 23 hours, and then aging for 6 days at a temperature of 83° C. to obtain modified graphene;

[0042] Step A2: ammonium molybdate, thiourea and deionized water are mixed evenly, and hydrothermally reacted at a temperature of 205° C. for 23 hours, then dried and the substrate is dispersed in hexanol, deionized water is added and mixed evenly, and KH570 is added under stirring at a speed of 200 r / min and a temperature of 83° C. After stirring for 6 hours, the filtrate is filtered to remove the filtrate, and the filter cake is washed with deionized water and dried to obtain functionalized molybdenum disulfide;

[0043] Step A3: Acryloyl chloride, imidazole, N,N-diisopropylethylamine and chloroform are mixed, and the reaction is carried out at a speed of 200 r / min and a temperature of 8°C for 4 hours to obtain intermediate 1. The modified graphene and functionalized molybdenum disulfide are dispersed in tetrahydrofuran, 2,2-dimethoxy-2-phenylacetophenone is added, and the reaction is carried out at a speed of 200 r / min and irradiation with a 365nm ultraviolet lamp for 35 minutes. After that, intermediate 1 is added, the reaction is continued for 35 minutes, and the filtrate is filtered to obtain lubricating particles.

[0044] The amount ratio of graphene oxide, dicyclohexylcarbodiimide and KH550 described in step A1 is 5.5g:0.4g:6mL, and the amount ratio of substrate, 3-mercaptopropyltrimethoxysilane and ammonium fluoride is 2g:3mL:0.3g.

[0045] The amount ratio of ammonium molybdate, thiourea and deionized water in step A2 is 2.47 g:2.284 g:70 mL, and the amount ratio of substrate, hexanol, deionized water and KH570 is 0.1 g:20 mL:5 mL:1 g.

[0046] The molar ratio of acryloyl chloride, imidazole and N,N-diisopropylethylamine described in step A3 is 1:1:1.1, the mass ratio of modified graphene, functionalized molybdenum disulfide and intermediate 1 is 3:0.5:1, and the amount of 2,2-dimethoxy-2-phenylacetophenone is 4% of the mass of modified graphene.

[0047] The modified base oil is prepared by the following steps:

[0048] Step B1: Castor oil and methyl ricinoleate are mixed, nitrogen is introduced for protection, aluminum chloride is added, and the reaction is carried out at a temperature of 123° C. for 4 hours, deionized water is added for quenching and the pH is adjusted to neutral, the water layer is removed, palladium carbon and n-hexane are added, nitrogen is introduced to expel the air, and hydrogen is introduced, and the reaction is carried out at a speed of 300 r / min and a temperature of 253° C. for 2-4 hours to obtain a base oil;

[0049] Step B2: Mix the base oil and methyl laurate, stir for 13 minutes at a speed of 800 r / min and a temperature of 85°C, add concentrated sulfuric acid, continue stirring for 6 hours, add deionized water to wash until the pH is neutral, remove the water layer, and obtain a modified base oil.

[0050] The amount ratio of castor oil, methyl ricinoleate, aluminum chloride, palladium carbon and n-hexane described in step B1 is 2g:8g:0.5g:0.2g:80mL.

[0051] The molar ratio of the hydroxyl group on the base oil and methyl laurate in step B2 is 1:1.2, and the amount of concentrated sulfuric acid used is 2.5% of the total mass of the base oil and methyl laurate. Example 3

[0052] A lubricating grease for automobile constant velocity joints is prepared by the following steps:

[0053] The modified base oil and lubricating particles are mixed evenly, stirred at a speed of 300 r / min and a temperature of 90°C, and 12-hydroxystearic acid is added. After stirring for 40 minutes, a lithium hydroxide aqueous solution is added and the temperature is raised to 105°C, and the reaction is carried out for 1.5 hours. Sebacic acid is added and the temperature is raised to 125°C, and the reaction is carried out for 40 minutes. The temperature is raised to 210°C and the heat is kept for 15 minutes to obtain grease for automobile constant velocity joints.

[0054] The mass ratio of the modified base oil, 12-hydroxystearic acid, lithium hydroxide and sebacic acid is 100:7.9:0.9:2.11, and the amount of the lubricating particles is 0.3% of the mass of the base oil.

[0055] The lubricating particles are prepared by the following steps:

[0056] Step A1: dispersing graphene oxide in THF, adding dicyclohexylcarbodiimide and KH550, stirring for 5 hours at a speed of 300 r / min and a temperature of 25°C, filtering and removing the filtrate, dispersing the substrate in dimethyl sulfoxide, adding 3-mercaptopropyltrimethoxysilane, stirring for 15 hours at a speed of 500 r / min and a temperature of 65°C, cooling to room temperature, adding ammonium fluoride and continuing to stir for 25 hours, and then aging at a temperature of 85°C for 9 days to obtain modified graphene;

[0057] Step A2: ammonium molybdate, thiourea and deionized water are mixed evenly, and hydrothermally reacted at a temperature of 210° C. for 25 hours, then dried and the substrate is dispersed in hexanol, deionized water is added and mixed evenly, and KH570 is added under stirring at a speed of 300 r / min and a temperature of 85° C. After stirring for 7 hours, the filtrate is filtered to remove the filtrate, and the filter cake is washed with deionized water and dried to obtain functionalized molybdenum disulfide;

[0058] Step A3: Acryloyl chloride, imidazole, N,N-diisopropylethylamine and chloroform are mixed, and reacted at a speed of 300 r / min and a temperature of 10°C for 5 hours to obtain intermediate 1. The modified graphene and functionalized molybdenum disulfide are dispersed in tetrahydrofuran, 2,2-dimethoxy-2-phenylacetophenone is added, and the reaction is carried out at a speed of 200 r / min and irradiation with a 365nm ultraviolet lamp for 40 minutes. After that, intermediate 1 is added, and the reaction is continued for 40 minutes. The filtrate is filtered to obtain lubricating particles.

[0059] The amount ratio of graphene oxide, dicyclohexylcarbodiimide and KH550 described in step A1 is 5.5g:0.4g:6mL, and the amount ratio of substrate, 3-mercaptopropyltrimethoxysilane and ammonium fluoride is 2g:3mL:0.3g.

[0060] The amount ratio of ammonium molybdate, thiourea and deionized water in step A2 is 2.47 g:2.284 g:70 mL, and the amount ratio of substrate, hexanol, deionized water and KH570 is 0.1 g:20 mL:5 mL:1 g.

[0061] The molar ratio of acryloyl chloride, imidazole and N,N-diisopropylethylamine described in step A3 is 1:1:1.1, the mass ratio of modified graphene, functionalized molybdenum disulfide and intermediate 1 is 3:0.5:1, and the amount of 2,2-dimethoxy-2-phenylacetophenone is 5% of the mass of modified graphene.

[0062] The modified base oil is prepared by the following steps:

[0063] Step B1: Castor oil and methyl ricinoleate are mixed, nitrogen is introduced for protection, aluminum chloride is added, and the reaction is carried out at a temperature of 125° C. for 5 hours, deionized water is added for quenching and the pH is adjusted to neutral, the water layer is removed, palladium carbon and n-hexane are added, nitrogen is introduced to expel the air, and hydrogen is introduced, and the reaction is carried out at a speed of 500 r / min and a temperature of 255° C. for 4 hours to obtain a base oil;

[0064] Step B2: Mix the base oil and methyl laurate, stir for 15 minutes at a speed of 800 r / min and a temperature of 90°C, add concentrated sulfuric acid, continue stirring for 7 hours, add deionized water to wash until the pH is neutral, remove the water layer, and obtain a modified base oil.

[0065] The amount ratio of castor oil, methyl ricinoleate, aluminum chloride, palladium carbon and n-hexane described in step B1 is 2g:8g:0.5g:0.2g:80mL.

[0066] The molar ratio of the hydroxyl group on the base oil and methyl laurate in step B2 is 1:1.2, and the amount of concentrated sulfuric acid used is 3% of the total mass of the base oil and methyl laurate.

[0067] Comparative Example 1

[0068] Compared with Example 1, this comparative example uses castor oil instead of modified base oil, and the remaining steps are the same.

[0069] Comparative Example 2

[0070] Compared with Example 1, this comparative example uses graphene instead of lubricating particles, and the remaining steps are the same.

[0071] Comparative Example 3

[0072] Compared with Example 1, this comparative example uses molybdenum disulfide instead of lubricating particles, and the remaining steps are the same.

[0073] The greases prepared in Examples 1-3 and Comparative Examples 1-3 were tested for friction coefficient and friction performance according to SH / T standards. The test conditions were: temperature 50°C, speed 1450r / min, loads of 392N, 549N and 696N, and test time 60min. The test results are shown in the following table.

[0074]

[0075] It can be seen from the above table that this application has a very good lubrication effect.

[0076] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A lubricating grease for a constant velocity joint of an automobile, characterized in that: Made by the following steps: The modified base oil and lubricating particles are mixed and stirred, and 12-hydroxystearic acid is added. After stirring, a lithium hydroxide aqueous solution is added and the temperature is raised to 100-105° C. for reaction. Sebacic acid is added and the temperature is raised to 120-125° C. for reaction. The temperature is raised to 200-210° C. for heat preservation to prepare a lubricating grease for automobile constant velocity joints. The lubricating particles are prepared by the following steps: Step A1: dispersing graphene oxide in THF, adding dicyclohexylcarbodiimide and γ-aminopropyltriethoxysilane, stirring, filtering and removing the filtrate, dispersing the substrate in dimethyl sulfoxide, adding 3-mercaptopropyltrimethoxysilane, stirring, cooling to room temperature, adding ammonium fluoride and continuing stirring, and then aging to obtain modified graphene; Step A2: After ammonium molybdate, thiourea and deionized water are mixed for hydrothermal reaction, the mixture is dried and the substrate is dispersed in hexanol, deionized water is added for mixing and stirring, and γ-methacryloxypropyltrimethoxysilane is added. After stirring, the filtrate is filtered to remove the filtrate, and the filter cake is washed with deionized water and dried to obtain functionalized molybdenum disulfide; Step A3: acryloyl chloride, imidazole, N,N-diisopropylethylamine and chloroform are mixed and reacted to obtain intermediate 1, modified graphene and functionalized molybdenum disulfide are dispersed in tetrahydrofuran, 2,2-dimethoxy-2-phenylacetophenone is added, and after ultraviolet irradiation reaction, intermediate 1 is added, the reaction is continued, and the filtrate is filtered to remove the filtrate to obtain lubricating particles; The modified base oil is prepared by the following steps: Step B1: Castor oil and methyl ricinoleate are mixed, nitrogen is introduced for protection, aluminum chloride is added, and after reaction, deionized water is added to quench and the pH is adjusted to neutral, the water layer is removed, palladium carbon and n-hexane are added, nitrogen is introduced to expel air, and hydrogen is introduced to react to obtain a base oil; Step B2: After the base oil and methyl laurate are mixed and stirred, concentrated sulfuric acid is added, stirring is continued, deionized water is added to wash until the pH is neutral, and the water layer is removed to obtain a modified base oil.

2. The lubricating grease for automobile constant velocity joints according to claim 1, characterized in that: The mass ratio of the modified base oil, 12-hydroxystearic acid, lithium hydroxide and sebacic acid is 100:7.9:0.9:2.11, and the amount of the lubricating particles is 0.1-0.3% of the mass of the base oil.

3. The lubricating grease for automobile constant velocity joints according to claim 1, characterized in that: The amount ratio of graphene oxide, dicyclohexylcarbodiimide and γ-aminopropyltriethoxysilane described in step A1 is 5.5g:0.4g:6mL, and the amount ratio of substrate, 3-mercaptopropyltrimethoxysilane and ammonium fluoride is 2g:3mL:0.3g.

4. The lubricating grease for automobile constant velocity joints according to claim 1, characterized in that: The amount ratio of ammonium molybdate, thiourea and deionized water in step A2 is 2.47 g:2.284 g:70 mL, and the amount ratio of substrate, hexanol, deionized water and γ-methacryloxypropyltrimethoxysilane is 0.1 g:20 mL:5 mL:1 g.

5. The lubricating grease for automobile constant velocity joints according to claim 1, characterized in that: The molar ratio of acryloyl chloride, imidazole and N,N-diisopropylethylamine described in step A3 is 1:1:1.1, the mass ratio of modified graphene, functionalized molybdenum disulfide and intermediate 1 is 3:0.5:1, and the amount of 2,2-dimethoxy-2-phenylacetophenone is 3-5% of the mass of modified graphene.

6. The lubricating grease for automobile constant velocity joints according to claim 1, characterized in that: The amount ratio of castor oil, methyl ricinoleate, aluminum chloride, palladium carbon and n-hexane described in step B1 is 2g:8g:0.5g:0.2g:80mL.

7. The lubricating grease for automobile constant velocity joints according to claim 1, characterized in that: The molar ratio of the hydroxyl group on the base oil and methyl laurate in step B2 is 1:1.2, and the amount of concentrated sulfuric acid used is 2-3% of the total mass of the base oil and methyl laurate.

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