Low-viscosity transmission lubricating oil composition as well as preparation and application thereof

Abstract

The invention discloses a low-viscosity transmission lubricating oil composition as well as preparation and application thereof. The lubricating oil composition mainly comprises the following components in parts by weight: 0.55-0.75 part of a phosphorus-containing agent; 0.2 to 0.6 part of sulfurized alkyl cyclohexanecarboxylate; 0.75 to 1.45 parts of an antioxidant; 2.1 to 3.5 parts of an ashless dispersant; 0.05 to 0.15 part of a clearing agent; 0.001 to 0.003 part of an anti-foaming agent; and the balance of base oil. The phosphorus-containing agent comprises a benzotriazole methylene thiophosphate ammonium salt; the antioxidant is 4, 4-methylene-(4, 4-diphenylamine)-bis (2, 6-di-tert-butylphenol). The apparent viscosity of the low-viscosity transmission lubricating oil composition provided by the invention at-40 DEG C is less than 2000mPa. S, the FZG (A10 / 16.6 R / 90) gear machine test is greater than grade 9, the FZG gear pitting corrosion resistance test time exceeds 400 hours, the transmission efficiency of a reduction gearbox reaches 98.5% or above, and the lubricating working condition requirements of a new generation of three-in-one electric drive reduction gearbox with the input rotating speed being 22000r / min or above can be met.

Description

Technical Field

[0001] The invention relates to a low-viscosity transmission lubricating oil composition and the preparation and application thereof. Background Art

[0002] With the continuous advancement of automobile electrification, more and more hybrid and electric vehicles use drive systems that integrate motors and transmissions in one housing. This integrated drive system requires a shared lubricant, which will come into contact with electrical modules, sensors and circuits, so the lubricant needs to have better cooling performance, insulation performance, copper corrosion protection and heat dissipation performance. Electric vehicles can generate maximum torque at zero speed, and the maximum speed is much higher than that of internal combustion engines and is constantly increasing. In addition, vehicles have higher requirements for transmission efficiency, smoothness, NVH and durability (service life), and the requirements for lubricants are also getting higher and higher. With the continuous development of new energy vehicle drive motor technology, drive motors are increasingly developing in the direction of high torque density and high power density. The motor speed exceeds 22,000 rpm and even reaches 30,000 rpm. Ultra-high speed motors need to have efficient heat dissipation capabilities to improve the continuous power and continuous torque of the motor. Ultra-high-speed motors above 22,000 rpm will become a subsequent technical trend, and the corresponding lubrication technology will become an indispensable solution. In order to achieve this effect, a lubricant with lower viscosity is needed. However, due to its low viscosity, the anti-wear performance of low-viscosity lubricants needs to be improved in order to provide long-term anti-wear protection for gears and bearings and meet the durability of gears, bearings and other moving parts. Summary of the invention

[0003] The present invention is made in order to at least partially solve the above-mentioned problems, improve the bearing protection performance and thermal stability of low-viscosity lubricating oil, enhance the load-bearing capacity and wear reduction effect of low-viscosity lubricating oil, and meet the lubrication working condition requirements of a new generation of three-in-one electric drive reduction box with an input speed of more than 22000r / min.

[0004] As a first aspect of the present invention, it relates to a low-viscosity transmission lubricating oil composition, which mainly comprises the following components in parts by weight:

[0005] Phosphorus-containing agent 0.55-0.75 parts;

[0006] 0.2-0.6 parts of alkyl cyclohexanecarboxylate sulfide;

[0007] 0.75-1.45 parts of antioxidant;

[0008] 2.1-3.5 parts of ashless dispersant;

[0009] 0.05-0.15 parts of detergent;

[0010] Antifoaming agent 0.001-0.003 parts;

[0011] The balance is base oil;

[0012] The phosphorus-containing agent includes benzotriazole methylene thiophosphate ammonium salt;

[0013] The antioxidant is 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol).

[0014] In one or some optional embodiments, the kinematic viscosity of the lubricating oil composition at 100° C. is 3.5 mm 2 / s or less.

[0015] In one or some optional embodiments, the cyclohexanecarboxylic acid alkyl sulfide is selected from at least one of n-dodecyl cyclohexanecarboxylate, n-tetradecyl cyclohexanecarboxylate, n-hexadecyl cyclohexanecarboxylate, and n-octadecyl cyclohexanecarboxylate.

[0016] In one or some optional embodiments, the benzotriazole methylene thiophosphate ammonium salt has the following structural formula:

[0017]

[0018] Among them, R1 is a straight-chain alkyl group or an isomeric alkyl group having 14 to 20 carbon atoms, and R2 is a straight-chain alkyl group or an isomeric alkyl group having 14 to 20 carbon atoms.

[0019] In one or some optional embodiments, the phosphorus-containing agent includes benzotriazole methylene thiophosphate ammonium salt, and also includes at least one of di-tert-butyl thiophosphate dodecylamine salt, di-tert-butyl thiophosphate tetradecylamine salt, di-tert-butyl thiophosphate hexadecylamine salt, and di-n-butyl thiophosphate octadecylamine salt.

[0020] In one or some optional embodiments, the antioxidant is 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol).

[0021] In one or some optional embodiments, the ashless dispersant is a mixture of phosphoborated mono-isobutylene succinimide and polyisobutylene succinimide.

[0022] In one or some optional embodiments, the mass ratio of the phosphoborated mono-heptyl polyisobutylene succinimide and the mixture of polyisobutylene succinimide is (1-5):10.

[0023] In one or some optional embodiments, the molecular weight of the phosphoborated mono-isobutylene succinimide is 2000-3000.

[0024] In one or some optional embodiments, the molecular weight of the polyisobutylene succinimide is 3000-3500.

[0025] In one or some optional embodiments, the detergent is sulfurized calcium alkylphenate.

[0026] In one or some optional embodiments, the TBN value of the sulfurized alkyl phenol calcium is 245-265.

[0027] In one or some optional embodiments, the anti-foaming agent is a polymethacrylate non-silicone anti-foaming agent.

[0028] In one or some optional embodiments, the molecular weight of the polymethacrylate non-silicone anti-foaming agent is 20,000.

[0029] In one or some optional embodiments, the base oil includes at least one of PAO, API Group II, and API Group III mineral base oils.

[0030] In one or some optional embodiments, the API Class II and API Class III mineral base oil is a 2-4 cSt base oil, and the PAO is a PAO2 base oil.

[0031] In one or some optional embodiments, the base oil further comprises a dispersant PMA type viscosity index improver.

[0032] In one or some optional embodiments, the content of the cyclohexanecarboxylic acid alkyl ester disulfide is 0.2 to 0.5 parts.

[0033] In one or some optional embodiments, the content of the antioxidant is 0.75 to 1.4 parts.

[0034] In one or some optional embodiments, the content of the ashless dispersant is 2.5 to 3.3 parts.

[0035] In one or some optional embodiments, the content of the antifoaming agent is 0.001-0.002 parts.

[0036] As a second aspect of the present invention, it relates to a method for preparing the above-mentioned low-viscosity transmission lubricating oil composition, comprising:

[0037] The phosphorus-containing agent, cyclohexanecarboxylic acid alkyl disulfide, antioxidant, ashless dispersant, detergent, antifoaming agent and base oil are mixed and stirred uniformly.

[0038] As a third aspect of the present invention, it relates to the use of the low-viscosity transmission lubricant oil composition in a vehicle reduction box.

[0039] The present invention uses an anti-wear system mainly composed of ammonium salt of benzotriazole methylene thiophosphate, so that the lubricating oil composition has outstanding load-bearing capacity and bearing protection performance, and can provide long-term anti-wear protection for gears and bearings.

[0040] The invention compounded benzotriazole methylene thiophosphate ammonium salt, cyclohexanecarboxylic acid alkyl sulfide and 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol), so that the lubricating oil composition has good thermal stability and friction reduction effect, thereby improving the transmission efficiency of the reduction box.

[0041] The lubricating oil composition provided by the present invention has an apparent viscosity of less than 2000 mPa.s at -40°C, an FZG (A10 / 16.6R / 90) gear machine test greater than level 9, an FZG gear anti-pitting test time of more than 400 hours, and a reduction box transmission efficiency of more than 98.5%, which can meet the lubrication working condition requirements of a new generation of three-in-one electric drive reduction boxes with an input speed of more than 22000 r / min. DETAILED DESCRIPTION

[0042] The following is a detailed description of the embodiments of the present invention: The embodiments of the present invention are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and processes are given, but the protection scope of the present invention is not limited to the following embodiments. The process parameters for which specific conditions are not specified in the following embodiments are generally based on conventional conditions.

[0043] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0044] The inventors implemented the relevant technical solution with reference to patent US11512263B2 and found that the kinematic viscosity of the lubricating composition at 100°C is about 3.5-7.0 mm 2 / s, but it does not solve the problem of bearing protection for ultra-high-speed gearboxes. The inventors implemented the relevant technical solutions with reference to patent CN114574270A and found that the kinematic viscosity of the lubricant is relatively high, and its kinematic viscosity at 100°C is 4.9-5.9 mm 2 / s. The inventors implemented the relevant technical solutions with reference to patent CN111117747A and found that the kinematic viscosity of the lubricating oil at 100°C is between 4.0 and 8.0 mm 2 / s, and can only be applied to reducers with a speed of 12000-16000r / min.

[0045] Based on the fact that the above cannot meet the lubrication working condition requirements of the new generation three-in-one electric drive reduction box with an input speed of more than 22000r / min, the inventor made the present invention after further research and development.

[0046] The benzotriazole methylene thiophosphate ammonium salt used in the embodiment of the present invention is prepared with reference to the relevant technical scheme disclosed in patent CN114717038B. The 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol) used in the embodiment of the present invention is Ethanox 4799 produced by SI, the phosphoborated mono-hanged polyisobutylene succinimide is H637 produced by Afton, the polyisobutylene succinimide is T161R produced by Xinxiang Ruifeng New Materials Co., Ltd., the sulfided alkylphenol calcium is OLOA 219 produced by CHEVRON, the polymethacrylate non-silicon antifoaming agent is H2030 produced by Afton, the PMA dispersibility viscosity index improver is V12-095 produced by Evonik Additives, the API III VHVI4 base oil is YOUBASE 4 produced by SK of South Korea, and the API II HVIH2 base oil is produced by Hebei Feitian Petrochemical Group Co., Ltd.

[0047] Example 1

[0048] The structural formula of the benzotriazole methylene thiophosphate ammonium salt used in this embodiment is as follows:

[0049]

[0050] Here, R1 and R2 are straight-chain alkyl groups having 14 carbon atoms.

[0051] 0.6 parts of benzotriazole methylene thiophosphate ammonium salt, 0.15 parts of di-tert-butyl thiophosphate tetradecylamine salt, 0.50 parts of cyclohexanecarboxylic acid n-octadecyl sulfide, 1.40 parts of 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol), 0.30 parts of phosphoborated mono-heptyl polyisobutylene succinimide with a molecular weight of 2000-3000, 3.0 parts of polyisobutylene succinimide with a molecular weight of 3000-3500, The imide, 0.15 parts of sulfurized alkyl phenol calcium with a TBN of 245-265, 0.001 parts of polymethacrylate non-silicone antifoaming agent with a molecular weight of 20000, 21.1 parts of API III VHVI4 base oil, 71.6 parts of API II HVIH2 base oil and 1.2 parts of PMA type dispersant viscosity index improver V12-095 were mixed uniformly to prepare a lubricating oil composition (I), and the performance test results are shown in Table 1.

[0052] Comparative Example 1

[0053] Except for 0.50 parts of n-octadecyl cyclohexanecarboxylate sulfurized and 0.75 parts of benzotriazole methylene thiophosphate ammonium salt, the rest is the same as the lubricating oil composition (I). The performance test results are shown in Table 1.

[0054] Comparative Example 2

[0055] Except for 0.50 parts of n-octadecyl cyclohexanecarboxylate sulfurized and 0.75 parts of di-tert-butyl thiophosphate tetradecylamine salt, the rest is the same as the lubricating oil composition (I). The performance test results are shown in Table 1.

[0056] Comparative Example 3

[0057] Except that 0.50 parts of n-octadecyl sulfide cyclohexanecarboxylate was replaced by 7.0 parts of Afton H35701, 21.1 parts of API III VHVI4 base oil was changed to 22.0 parts of API III VHVI4 base oil, and the rest were the same as composition (I). The performance test results are shown in Table 1.

[0058] Table 1 Performance test results of the lubricating oil compositions in Example 1 and Comparative Examples 1 to 3

[0059]

[0060] From the analysis of the results in Table 1, it can be seen that compared with Comparative Examples 1 to 3, Example 1 of the present invention uses benzotriazole methylene thiophosphate ammonium salt and di-tert-butyl thiophosphate tetradecylamine salt to compound the anti-wear performance of the oil, so that it has outstanding load-bearing capacity and bearing protection performance. The FZG (A10 / 16.6R / 90) gear machine test reaches more than 9 levels, while the FZG gear anti-pitting test time reaches 428 hours, and the FE-8 bearing wear is only 0.8 mg, providing long-term anti-wear protection for gears and bearings. Compared with Example 1 of the present invention, Comparative Example 1 uses benzotriazole methylene thiophosphate ammonium salt alone, and Comparative Example 2 uses di-tert-butyl thiophosphate tetradecylamine salt alone, which will reduce the load-bearing capacity of FZG, shorten the pitting test time of FZG, and increase the wear weight loss of FE-8, and fail to meet the index requirements. Compared with Example 1 of the present invention, Comparative Example 3 uses imported Afton H35701 compound blended oil, and the kinematic viscosity at 100°C is 3.26 mm 2 / s, the FZG load-bearing capacity, FZG gear anti-pitting test and FE-8 bearing wear test cannot meet the index requirements.

[0061] Example 2

[0062] The structural formula of the benzotriazole methylene thiophosphate ammonium salt used in this embodiment is as follows:

[0063]

[0064] Wherein R1 and R2 are straight-chain alkyl groups having 20 carbon atoms.

[0065] 0.30 parts of benzotriazole methylene thiophosphate ammonium salt, 0.25 parts of di-tert-butyl thiophosphate tetradecylamine salt, 0.20 parts of cyclohexanecarboxylic acid n-dodecyl sulfide, 0.75 parts of 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol), 0.70 parts of phosphoborated mono-heptyl polyisobutylene succinimide with a molecular weight of 2000-3000, 1.40 parts of polyisobutylene succinimide with a molecular weight of 3000-3500, 0. 0.05 parts of sulfurized alkyl phenol calcium with a TBN of 245-265, 0.002 parts of polymethacrylate non-silicone antifoaming agent with a molecular weight of 20000, 23.70 parts of API III VHVI4 base oil, 21.45 parts of API II HVIH2 base oil, 50.0 parts of PAO2 base oil and 1.2 parts of PMA type dispersant viscosity index improver V12-095 were mixed uniformly to prepare a lubricating oil composition (II), and the performance test results are shown in Table 2.

[0066] Comparative Example 4

[0067] Except that 0.30 parts of benzotriazole methylene thiophosphate ammonium salt and 0.25 parts of di-tert-butyl thiophosphate tetradecylamine salt are replaced by 0.55 parts of sulfided isobutylene, the rest are the same as composition (II). The performance test results are shown in Table 2.

[0068] Comparative Example 5

[0069] Except for 0.75 parts of 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol), the rest are the same as composition (II). The performance test results are shown in Table 2.

[0070] Table 2 Performance test results of the lubricating oil compositions in Example 2, Comparative Example 4 and Comparative Example 5

[0071]

[0072] From the analysis of the results in Table 2, it can be seen that compared with Comparative Examples 4 and 5, Example 2 of the present invention uses benzotriazole methylene thiophosphate ammonium salt, cyclohexanecarboxylic acid alkyl sulfide, etc. to compound, which has a good synergistic effect, so that the lubricating oil composition exhibits more excellent long-term anti-copper corrosion performance, and can also improve transmission efficiency, greatly reduce the increase in acid value, and thus extend the service life of the oil. Example 2 of the present invention uses 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol) as an antioxidant. Compared with Comparative Example 5 using 4,4-methylene-bis(2,6-di-tert-butylphenol) as an antioxidant, the antioxidant used in the present invention exhibits better antioxidant performance in the formula.

[0073] Example 3

[0074] The structural formula of the benzotriazole methylene thiophosphate ammonium salt used in this embodiment is as follows:

[0075]

[0076] Here, R1 and R2 are straight-chain alkyl groups having 16 carbon atoms.

[0077] 0.60 parts of benzotriazole methylene thiophosphate ammonium salt, 0.10 parts of di-tert-butyl thiophosphate hexadecyl salt, 0.45 parts of cyclohexanecarboxylic acid n-octadecyl sulfide, 1.35 parts of 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol), 0.70 parts of phosphoborated mono-hanged polyisobutylene succinimide with a molecular weight of 2000-3000, 2.80 parts of polyisobutylene succinimide with a molecular weight of 3000-3500, 0.10 parts of sulfided alkylphenol calcium with a TBN value of 245-265, 0.003 parts of polymethacrylate non-silicone antifoaming agent with a molecular weight of 20000, 21.55 parts of API III VHVI4 base oil, 71.15 parts of PAO 2 base oils and 1.2 parts of PMA type dispersant viscosity index improver V12-095 were uniformly mixed to prepare a lubricating oil composition (III). The performance test results are shown in Table 3.

[0078] Table 3 Performance test results of the lubricating oil composition in Example 3

[0079]

[0080]

[0081] From the results in Table 3, it can be seen that the kinematic viscosity of the lubricating oil composition (III) at 100°C is 3.11 mm 2 / s, -40℃ apparent viscosity 1260mPa.s, FZG (A10 / 16.6R / 90) gear machine test reaches more than level 9, and FZG gear anti-pitting test time reaches 452 hours. The lubricating oil composition provided by the present invention has excellent low-temperature fluidity, outstanding gear protection and bearing anti-pitting performance, and a transmission efficiency of 98.95%, which can meet the lubrication working condition requirements of a new generation of three-in-one electric drive reduction box with an input speed of more than 22000r / min.

[0082] Although the specific embodiments of the present invention have been described in detail, it will be understood by those skilled in the art. According to all the teachings disclosed, various modifications and replacements can be made to those details, and these changes are all within the protection scope of the present invention. The full scope of the present invention is given by the attached claims and any equivalents thereof.

Claims

1. A low-viscosity transmission lubricant composition, characterized in that: The lubricating oil composition mainly comprises the following components by weight: Phosphorus-containing agent 0.55-0.75 parts; 0.2-0.6 parts of alkyl cyclohexanecarboxylate sulfide; 0.75-1.45 parts of antioxidant; 2.1-3.5 parts of ashless dispersant; 0.05-0.15 parts of detergent; Antifoaming agent 0.001-0.003 parts; The balance is base oil; The phosphorus-containing agent includes benzotriazole methylene thiophosphate ammonium salt; The antioxidant is 4,4-methylene-(4,4-diphenylamine)-bis(2,6-di-tert-butylphenol).

2. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The kinematic viscosity of the lubricating oil composition at 100° C. is 3.5 mm 2 / s or less.

3. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The cyclohexanecarboxylic acid alkyl sulfide is selected from at least one of n-dodecyl cyclohexanecarboxylate, n-tetradecyl cyclohexanecarboxylate, n-hexadecyl cyclohexanecarboxylate, and n-octadecyl cyclohexanecarboxylate.

4. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The benzotriazole methylene thiophosphate ammonium salt has the following structural formula: Among them, R1 is a straight-chain alkyl group or an isomeric alkyl group having 14 to 20 carbon atoms, and R2 is a straight-chain alkyl group or an isomeric alkyl group having 14 to 20 carbon atoms.

5. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The phosphorus-containing agent further comprises at least one of di-tert-butyl thiophosphate dodecylamine salt, di-tert-butyl thiophosphate tetradecylamine salt, di-tert-butyl thiophosphate hexadecylamine salt, and di-n-butyl thiophosphate octadecylamine salt.

6. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The ashless dispersant is a mixture of phosphoborated monoisobutylene succinimide and polyisobutylene succinimide.

7. The low-viscosity transmission lubricating oil composition according to claim 6, characterized in that: The mass ratio of the phosphoborated mono-heptyl polyisobutylene succinimide and the polyisobutylene succinimide mixture is (1-5):

10.

8. The low-viscosity transmission lubricating oil composition according to claim 6, characterized in that: The molecular weight of the phosphoborated mono-heptyl polyisobutylene succinimide is 2000-3000.

9. The low-viscosity transmission lubricating oil composition according to claim 6, characterized in that: The molecular weight of the polyisobutylene succinimide is 3000-3500.

10. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The detergent is calcium sulfide alkyl phenate.

11. The low-viscosity transmission lubricating oil composition according to claim 10, characterized in that: The TBN value of the sulfurized alkyl phenate calcium is 245-265.

12. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The antifoaming agent is a polymethacrylate non-silicon antifoaming agent.

13. The low-viscosity transmission lubricating oil composition according to claim 12, characterized in that: The molecular weight of the polymethacrylate non-silicon antifoaming agent is 20,000.

14. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The base oil includes at least one of PAO base oil, API II and API III mineral base oil.

15. The low-viscosity transmission lubricating oil composition according to claim 14, characterized in that: The API II and API III mineral base oils are 2-4 cSt base oils, and the PAO base oil is PAO2 base oil.

16. The low-viscosity transmission lubricating oil composition according to claim 14, characterized in that: The base oil also includes a dispersant PMA type viscosity index improver.

17. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The content of the cyclohexanecarboxylic acid alkyl ester disulfide is 0.2 to 0.5 parts.

18. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The content of the antioxidant is 0.75 to 1.4 parts.

19. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The content of the ashless dispersant is 2.5 to 3.3 parts.

20. The low-viscosity transmission lubricating oil composition according to claim 1, characterized in that: The content of the antifoaming agent is 0.001 to 0.002 parts.

21. A method for preparing the low-viscosity transmission lubricant oil composition according to any one of claims 1 to 20, characterized in that: include: The phosphorus-containing agent, cyclohexanecarboxylic acid alkyl disulfide, antioxidant, ashless dispersant, detergent, antifoaming agent and base oil are mixed and stirred uniformly.

22. Use of the low-viscosity transmission lubricant oil composition according to any one of claims 1 to 20 in a vehicle reduction box.

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