A mannich ashless dispersant, lubricating oil composition and application thereof

Abstract

The application provides a Mannich ashless dispersant, a lubricating oil composition and application thereof, the Mannich ashless dispersant has a structure shown in formula I: wherein R1 is selected from H, a hydroxyl group, a C1-C 12 The composition comprises 3-7 wt% of the ashless dispersant, 0.05-0.3 wt% of a detergent, 0.7-1.5 wt% of an anti-wear agent, 1.5-4 wt% of an antioxidant, 0.01-0.1 wt% of a corrosion inhibitor, 0.2-0.6 wt% of a friction modifier, 0.001-0.003 wt% of an antifoaming agent and the balance of base oil, with the total weight of the lubricating oil composition being 100%. The lubricating oil composition has excellent electrochemical performance, mechanical protection performance, synchronizer durability and friction characteristics, heat conduction performance and material compatibility.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, and specifically relates to a lubricating oil composition for electric vehicle gearboxes. Background Technology

[0002] Pure electric vehicles and hybrid electric vehicles are experiencing explosive growth globally. Currently, the mature pure electric passenger vehicles on the market mainly use independent single-speed or two-speed reduction mechanisms. With technological advancements, there is a trend towards integrating synchronizers, clutches, gear reducers, and motors in passenger vehicle gearboxes. This necessitates that the required gearbox lubricating oil possess five key performance characteristics: good electrochemical properties, excellent mechanical protection performance, superior synchronizer durability and clutch friction stability, good thermal conductivity, and material compatibility.

[0003] Electrochemical performance considerations include insulation performance evaluation tests, such as conductivity, breakdown voltage, and volume resistivity, as the oil needs to come into direct contact with the motor. Mechanical protection performance considerations include the oil's need to lubricate planetary gears, differentials, and bearings, requiring a certain load-bearing capacity. Synchronizer durability and friction characteristics considerations include good durability across different synchronizer materials, ensuring clutch friction stability for smooth shifting, as the oil needs to lubricate the synchronizer and clutch. Thermal conduction performance considerations include oxidation tests, anti-foaming tests, and specific heat capacity tests, as the oil needs to cool the integrated gearbox and remove heat. Material compatibility considerations include extended-time copper corrosion tests and motor material compatibility tests, as the oil needs to come into contact with coatings and copper materials. CN105132107B discloses a lubricating oil composition for a pure electric vehicle transmission. This composition uses extreme pressure anti-wear agents such as hydroxythiadiazole derivatives and antioxidants such as high molecular weight phenols containing sulfide groups, giving the oil excellent anti-wear properties and oxidation resistance. However, it cannot simultaneously meet the requirements for electrochemical performance, mechanical protection performance, synchronizer durability, and clutch friction stability. CN104560297B discloses a lubricating oil composition for a reducer in a hybrid vehicle or electric vehicle. It selects a synthetic base oil with a low traction coefficient and a pour point depressant with a weight-average molecular weight of 40,000-100,000. The composition provides excellent low-temperature fluidity and shear stability, but it does not mention the oil's mechanical protection performance and clutch friction stability. CN114302940A discloses the use of lubricants containing carboxylic acid esters in electric vehicles, but it does not address the synchronizer durability and clutch friction stability performance of the oil, nor does it mention the oil's transmission efficiency. Traditional automatic transmission fluids like ATF and GL-5 gear oil cannot simultaneously meet these performance requirements. Specialized formulation technology is needed; otherwise, problems such as internal power supply circuit failures, mechanical wear, premature oxidation, and shift shocks may occur in the gearbox. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a Mannich ashless dispersant, a lubricating oil composition, and its application, wherein the lubricating oil composition possesses excellent electrochemical properties, mechanical protection properties, synchronizer durability and frictional characteristics, thermal conductivity, and material compatibility.

[0005] To achieve the above objectives, the present invention provides a Mannich ashless dispersant having the structure shown in Formula I:

[0006]

[0007] In Formula I, R1 is selected from H, hydroxyl group, C1-C 12 The hydrocarbon group and aromatic group, n is 2-6.

[0008] According to a specific embodiment of the present invention, preferably, the molecular weight of PIB (polyisobutylene) is 900-2500.

[0009] The present invention also provides a method for preparing the above-mentioned Mannich ashless dispersant, which includes the following steps:

[0010] (1) Mix high molecular weight polyisobutylene maleic anhydride and base oil, heat to 90-110℃, add polyethylene polyamine dropwise, then continue heating to 120-130℃ for 2-4 hours, introduce protective gas, raise the temperature to 150-160℃ and react for 6-8 hours to obtain intermediate product.

[0011] (2) Mix the intermediate product obtained in step (1), phenolic compounds and xylene, introduce a protective gas, heat to 60-70°C, add formaldehyde dropwise and react for 8-10 hours, raise the temperature to 150-160°C and react for 6-8 hours to obtain the Mannich ashless dispersant.

[0012] According to a specific embodiment of the present invention, preferably, the molar ratio of the polymeric polyisobutylene maleic anhydride to the base oil is 2.5-3:1.

[0013] According to a specific embodiment of the present invention, preferably, the molar ratio of the polymeric polyisobutylene maleic anhydride to polyethylene polyamine is 11-13:1.

[0014] According to a specific embodiment of the present invention, preferably, the base oil includes one or a combination of two or more of HVIH6, HVIP6, and VHVI6.

[0015] According to a specific embodiment of the present invention, preferably, the molar ratio of the phenolic compound and xylene is 0.2-0:4:1.

[0016] According to a specific embodiment of the present invention, preferably, the molar ratio of formaldehyde to phenolic compounds is 1:4-6.

[0017] According to a specific embodiment of the present invention, the preparation method of the above-mentioned Mannich ashless dispersant includes the following specific steps:

[0018] (1) Mix and stir the high molecular weight polyisobutylene maleic anhydride and base oil evenly, heat to 90-110℃ and stir for 0.5-1 hour, slowly add polyethylene polyamine, then continue to heat to 120-130℃ and react for 2-4 hours, introduce nitrogen gas, then raise the temperature to 150-160℃ and react for 6-8 hours, filter and cool to obtain intermediate product;

[0019] (2) Mix the intermediate product, phenolic compounds and xylene evenly, introduce nitrogen gas, heat to 60-70℃, slowly add formaldehyde and react for 8-10 hours, raise the temperature to 150-160℃ and react for 6-8 hours, filter and cool to obtain the Mannich ashless dispersant.

[0020] The present invention also provides a lubricating oil composition, which, calculated by weight of 100%, comprises: 3-7 wt% ashless dispersant, 0.05-0.3 wt% detergent, 0.7-1.5 wt% anti-wear agent, 1.5-4 wt% antioxidant, 0.01-0.1 wt% corrosion inhibitor, 0.2-0.6 wt% friction modifier, 0.001-0.003 wt% antifoaming agent, with the balance being base oil; the ashless dispersant comprises a mixture of Mannich ashless dispersant (a phenolic high-molecular-weight polyisobutylene succinimide) and anti-wear dispersant (boronized succinimide), wherein the Mannich ashless dispersant is the aforementioned Mannich ashless dispersant; the anti-wear dispersant has the structure shown in Formula II:

[0021]

[0022] In Formula II, R2 is selected from isobutyl, isopentyl, isohexyl, isoheptyl, isooctyl, and isononyl, and m is 2-6.

[0023] According to a specific embodiment of the present invention, preferably, the preparation method of the anti-wear dispersant represented by Formula II includes the following steps:

[0024] Low molecular weight polyisobutylene maleic anhydride and base oil are mixed and stirred evenly, then heated to 80-100℃. Polyene polyamine is slowly added dropwise, and the temperature is raised to 150-160℃ for 2-4 hours. After cooling to room temperature, boric acid and isooctanol are added, and the temperature is slowly raised to 140-160℃. After reacting for 4-6 hours, nitrogen gas is introduced for stripping, and the mixture is filtered to obtain the anti-wear dispersant.

[0025] According to a specific embodiment of the present invention, preferably, the lubricating oil composition comprises, based on a total weight of 100%, 3.6-5.4 wt% ashless dispersant, 0.1-0.3 wt% detergent, 0.8-1.5 wt% anti-wear agent, 1.5-2.5 wt% antioxidant, 0.01-0.05 wt% corrosion inhibitor, 0.2-0.4 wt% friction modifier, 0.002-0.003 wt% antifoaming agent, with the balance being base oil.

[0026] According to a specific embodiment of the present invention, preferably, in Formula I, R1 is selected from hydroxyl and methyl.

[0027] According to a specific embodiment of the present invention, preferably, the mass ratio of the Mannich ashless dispersant to the anti-wear dispersant is 1:(0.1-0.2).

[0028] According to a specific embodiment of the present invention, preferably, the mass ratio of the Mannich ashless dispersant and the anti-wear dispersant is 1:0.2.

[0029] According to a specific embodiment of the present invention, preferably, the anti-wear agent comprises C 12- C 14 A mixture of tertiary alkyl amines, ammonium alkyl phosphates, and dodecyl phosphites.

[0030] According to a specific embodiment of the present invention, preferably, the alkyl phosphate ammonium salt includes dodecyl phosphate salt and / or butyl hexyl phosphate salt.

[0031] According to a specific embodiment of the present invention, preferably, the C 12- C 14 The tertiary alkyl amines account for 0.05-0.2% of the total mass of the lubricating oil composition.

[0032] According to a specific embodiment of the present invention, preferably, the mass ratio of the alkyl phosphate ammonium salt to the dodecyl phosphite is (0.1-0.25):1.

[0033] According to a specific embodiment of the present invention, preferably, the antioxidant comprises a mixture of phenolic amine antioxidants and phenolic ester antioxidants; the phenolic amine antioxidant simultaneously contains hindered phenolic and diphenylamine functional groups.

[0034] According to a specific embodiment of the present invention, preferably, the phenolic amine antioxidant comprises 4-methylene-(4-diphenylamine)-2,6-di-tert-butylphenol and / or 4-methylene-(4-diphenylamine)-bis(2,6-di-tert-butylphenol); wherein, the structure of 4-methylene-(4-diphenylamine)-2,6-di-tert-butylphenol is as follows:

[0035]

[0036] The structure of 4-methylene-(4-diphenylamine)-bis(2,6-di-tert-butylphenol) is as follows:

[0037]

[0038] According to a specific embodiment of the present invention, preferably, the phenolic ester antioxidant includes isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

[0039] According to a specific embodiment of the present invention, preferably, the mass ratio of the phenolic amine antioxidant to the phenolic ester antioxidant is 1:(0.25-0.5).

[0040] According to a specific embodiment of the present invention, preferably, the mass ratio of the phenolic amine antioxidant to the phenolic ester antioxidant is 1:0.5.

[0041] According to a specific embodiment of the present invention, preferably, the corrosion inhibitor comprises 5-methyltriazole methylene C 12 -C 14 One or more of the following: tert-alkyl primary amines, 5-methylbenztriazole methylene dodecyl primary amines, and 5-methylbenztriazole methylene tetradecyl primary amines.

[0042] According to a specific embodiment of the present invention, preferably, the friction modifier comprises C4-C 12 A mixture of alkyl borate esters and potassium tetraborate.

[0043] According to a specific embodiment of the present invention, preferably, the potassium tetraborate accounts for 10% of the mass fraction of the friction modifier.

[0044] According to a specific embodiment of the present invention, preferably, the base oil comprises one or more of the following: a viscosity index improver of dispersible PAM with a molecular weight of 30,000-100,000, API Group I 150BS mineral base oil, poly-alpha olefin, and ester base oil.

[0045] According to a specific embodiment of the present invention, preferably, the mass ratio of poly-α-olefin to ester base oil in the base oil is 4:1.

[0046] According to a specific embodiment of the present invention, preferably, the detergent comprises calcium alkylbenzene sulfonate with a TBN of 300-320.

[0047] According to a specific embodiment of the present invention, preferably, the antifoaming agent includes a dimethyl silicone oil antifoaming agent and / or a perfluoropolyether modified polysiloxane antifoaming agent; more preferably, the molecular weight of the dimethyl silicone oil antifoaming agent is about 60,000.

[0048] According to a specific embodiment of the present invention, preferably, the kinematic viscosity of the lubricating oil composition at 100°C is 5.0-6.0 mm. 2 / s.

[0049] The present invention also provides a lubrication method using the above-mentioned lubricating oil composition.

[0050] According to a specific embodiment of the present invention, preferably, the lubrication method is used for the gearbox of an electric vehicle, for example, for a pure electric hybrid vehicle containing a wet multi-ratio gearbox with a synchronizer and a clutch.

[0051] The present invention has the following beneficial effects:

[0052] (1) The present invention uses a special structure of ashless dispersant, anti-wear agent and friction modifier in a certain proportion to improve the anti-wear performance of oil while also significantly improving the synchronous durability and friction characteristics of oil, and significantly improving the transmission efficiency of gearbox.

[0053] (2) The antioxidants and corrosion inhibitors used in this invention can improve the long-term corrosion resistance of oil against copper materials, and also enable the oil to have good electrochemical properties after aging.

[0054] (3) The base oil used in this invention is compounded with specific additives to ensure that the oil has good shear stability, electrochemical performance, good mechanical protection performance, excellent synchronizer durability and clutch friction stability, good thermal conductivity and material compatibility.

[0055] The lubricating oil composition of this invention can effectively lubricate components such as the motor, planetary reducer, synchronizer, and clutch inside the gearbox, effectively reducing gear wear, improving the transmission efficiency and shifting smoothness of the gearbox, and ensuring the safe and efficient operation of the motor. With the rapid development of the pure electric vehicle or hybrid vehicle industry, there is a huge demand for corresponding gearbox oils, indicating broad prospects for promotion and application. Attached Figure Description

[0056] Figure 1 Infrared spectrum of the product of Preparation Example 1;

[0057] Figure 2 The infrared spectrum of the product of Preparation Example 2. Detailed Implementation

[0058] To provide a clearer understanding of the technical features, objectives, and beneficial effects of this invention, the technical solution of this invention is described in detail below, but this should not be construed as limiting the scope of implementation of this invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0059] In the following preparation examples, the polymeric polyisobutylene maleic anhydride was purchased from Liaoning Tianhe Fine Chemical Co., Ltd. or Xinxiang Ruifeng New Material Co., Ltd.; the polyethylene polyamine was purchased from Dow Chemical Company, USA; and the base oil was selected from HVIH6, HVIP6, and VHVI6 of China National Petroleum Corporation that meet the Q / SY 44 standard.

[0060] Preparation Example 1

[0061] This preparation example provides a phenol-containing polymeric polyisobutylene succinimide, the preparation method of which includes the following steps:

[0062] (1) Add 70g of polyisobutylene maleic anhydride and 25g of HVIH6 base oil to a 250ml flask, heat to 90℃ and stir for 1 hour, slowly add 5.5g of polyethylene polyamine, heat to 120-130℃ and react for 4 hours, under nitrogen protection, heat to 160℃ at 10℃ per hour and react for 8 hours, filter and cool to obtain about 100g of intermediate product;

[0063] (2) Mix 100g of intermediate product, 1.2g of resorcinol, and 5g of xylene thoroughly, and add the mixture to a 250ml flask. Under nitrogen protection, heat to 60℃, slowly add 0.3g of formaldehyde, and react for 10 hours. Then raise the temperature to 150-160℃ and react for 8 hours. After filtration and cooling, the Mannich ashless dispersant is obtained. Its infrared spectrum information is shown in Table 1. The infrared spectrum is shown in [Table 1]. Figure 1 .

[0064] Table 1. Assignment of infrared absorption peaks in the phenol-containing polymer polyisobutylene succinimide.

[0065]

[0066] The phenol-containing polymeric polyisobutylene succinimide used in the following examples was synthesized according to this method.

[0067] Preparation Example 2

[0068] This preparation example provides a boron-esterified succinimide, the preparation method of which includes the following steps:

[0069] (1) 37.5g of low molecular weight polyisobutylene maleic anhydride and 41g of HVIH5 base oil were added to a 250ml flask. The temperature was raised to 90-100℃, and 3.5g of polyene polyamine was slowly added dropwise. Then, nitrogen gas was introduced for protection, and the temperature was raised to 150-160℃ for 4 hours. The temperature was lowered to below 60℃, and the nitrogen gas was turned off. 6g of boric acid and 25g of isooctyl alcohol were added, and the temperature was slowly raised to 140-160℃. Nitrogen gas was introduced for protection, and the temperature was raised to 160℃ for 4 hours. After filtration, the boron esterified succinimide anti-wear dispersant was obtained. Its infrared spectrum information is shown in Table 2. The infrared spectrum is shown in Table 2. Figure 2 .

[0070] Table 2 Infrared absorption peaks of boron esterified succinimide

[0071] <![CDATA[Wave number (cm -1 )]]> Assignment of infrared characteristic peaks 2956 / 2926 <![CDATA[CH3, CH2 stretching vibration]]> 1773 Antisymmetric vibrations of cyclic imine structures 1704 Symmetric vibrations of cyclic imine structure 1640 Carbonyl vibration in open-chain amide structures 1464 / 1364 Bending vibration of methyl CH bond 1334 Stretching vibrations of BO bonds in borate esters 1232 tert-butyl structure vibration

[0072] The boron-esterified succinimide used in the following examples was synthesized according to this method.

[0073] Example 1

[0074] This embodiment provides a lubricating oil composition (I) for an electric vehicle gearbox, comprising:

[0075] A mixture of 4.5 wt% Mannich ashless dispersant (R1 is hydroxyl) and 0.9 wt% boron esterified succinimide dispersant (R2 is isobutyl, m is 2-6) (component A);

[0076] 0.3wt% alkylbenzene sulfonate calcium (component B) with TBN around 300-320;

[0077] 0.1wt% C 12 -C 14 Tertiary alkyl amine, 0.14 wt% butylhexyl phosphate dodecammonium salt, 0.56 wt% dodecyl phosphite (component C);

[0078] 1.0 wt% of 4-methylene-(4-diphenylamine)-2,6-di-tert-butylphenol, 0.5 wt% of isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (component D);

[0079] 0.01 wt% of 5-methylbenztriazole methylene dodecylamine (component E);

[0080] 0.3wt% friction modifier, namely C4-C 12 A mixture of alkyl borate esters and potassium tetraborate (component F);

[0081] 0.003 wt% of dimethyl silicone oil antifoaming agent with a molecular weight of 60,000 (component G);

[0082] 4.5 wt% Evonik V12-292 viscosity index enhancer, 5.0 wt% HVIS150BS, 65.747 wt% PAO 4, and 16.44 wt% adipate base oil (component H). The sum of the above components is 100 wt%.

[0083] Comparative Example 1

[0084] This comparative example provides a lubricating oil composition that is identical to composition (I) except that component (A) is replaced by 5.4 wt% Mannich ashless dispersant (R1 is hydroxyl, n is 2-6).

[0085] Comparative Example 2

[0086] This comparative example provides a lubricating oil composition that is identical to composition (I) except that component (C) is replaced by 0.14 wt% butylhexyl phosphate dodecammonium salt and 0.66 wt% dodecyl phosphite.

[0087] Comparative Example 3

[0088] This comparative example provides a lubricating oil composition that is identical to composition (I) except that component (F) is replaced by 0.3 wt% of PAO4 base oil.

[0089] The test results of the compositions obtained in Example 1 and Comparative Examples 1, 2, and 3 are shown in Table 3.

[0090] Table 3 Test Results

[0091]

[0092] Table 3 shows that (1) compared with Comparative Examples 1, 2, and 3, Composition I exhibits superior clutch friction characteristics, anti-wear performance, and transmission efficiency, indicating that the use of a special structured ashless dispersant, a specific structured anti-wear agent, and a friction modifier in a certain proportion can improve the anti-wear performance of the oil while enhancing its synchronous durability and friction characteristics, and improving the transmission efficiency of the gearbox; (2) compared with Comparative Example 2, the compound use of anti-wear agents is beneficial to improving the anti-wear performance of the oil, and the lack of C 12 -C 14 Tertiary alkyl amines will be detrimental to the friction characteristics of the oil and synchronizer test; (3) Compared with Comparative Example 3, the use of friction modifiers is beneficial to improving the friction characteristics and conventional efficiency of the oil.

[0093] Example 2

[0094] This embodiment provides a lubricating oil composition (II) for an electric vehicle gearbox, comprising:

[0095] A mixture of 3.0 wt% Mannich ashless dispersant (R1 is methyl, n is 2-6) and 0.6 wt% boron esterified succinimide dispersant (R2 is isooctyl, m is 2-6) (component A);

[0096] 0.2wt% of calcium alkylbenzene sulfonate with TBN around 300-320 (component B);

[0097] 0.16wt% C12 -C 14 Tertiary alkyl amine, 0.12 wt% dodecyl phosphate salt, 1.2 wt% dodecyl phosphite (component C);

[0098] 2.0 wt% of 4-methylene-(4-diphenylamine)-bis(2,6-di-tert-butylphenol), 0.5 wt% of isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (component D);

[0099] 0.05 wt% of 5-methylbenztriazole methylenetetradecylamine (component E);

[0100] 0.4 wt% friction modifier, namely C4-C 12 A mixture of alkyl borate esters and potassium tetraborate (component F);

[0101] 0.001 wt% of dimethyl silicone oil antifoaming agent with a molecular weight of 60,000 (component G);

[0102] 4.5 wt% Evonik V12-095 viscosity index enhancer, 5.0 wt% HVIS150BS, 65.819 wt% PAO 4, and 16.45 wt% pentaerythritol ester base oil (component H). The sum of the above components is 100 wt%.

[0103] Comparative Example 4

[0104] This comparative example provides a lubricating oil composition that is identical to composition (II) except that component (D) is replaced by 2.5 wt% of 4-methylene-(4-diphenylamine)-bis(2,6-di-tert-butylphenol).

[0105] Comparative Example 5

[0106] This comparative example provides a lubricating oil composition, except that component (E) is mixed with 0.05 wt% of 5-methylbenztriazole methylene C. 12 -C 14 Except for the substitution of tertiary alkyl amines, all other components are the same as composition (I).

[0107] The test results of the compositions obtained in Example 2, Comparative Examples 4 and 5 are shown in Table 4.

[0108] Table 4 Test Results

[0109]

[0110]

[0111] Table 4 shows that (1) compared with Comparative Example 4 and Comparative Example 5, Composition II exhibits superior long-term copper strip corrosion resistance and electrochemical performance, indicating that the specially structured antioxidant and corrosion inhibitor can improve the long-term corrosion resistance of the oil and also enable the oil to have good electrochemical performance after aging; (2) compared with Comparative Example 4, the combined use of antioxidants is beneficial to improving the long-term corrosion resistance and electrochemical performance of the oil after aging; (3) compared with Comparative Example 5, 5-methylbenztriazole methylene C 12 -C 14 The use of tertiary alkyl amines is beneficial for improving the long-term corrosion resistance of oils.

[0112] Example 3

[0113] This embodiment provides a lubricating oil composition (Ⅲ) for an electric vehicle gearbox, comprising:

[0114] A mixture of 4.0 wt% Mannich ashless dispersant (R1 is methyl, n is 2-6) and 0.8 wt% boron esterified succinimide dispersant (R2 is isohexyl, m is 2-6) (component A);

[0115] 0.2wt% of calcium alkylbenzene sulfonate with TBN around 300-320 (component B);

[0116] 0.05wt% C 12 -C 14 Tertiary alkyl amine, 0.1 wt% butylhexyl phosphate dodecammonium salt, 1.0 wt% dodecyl phosphite (component C);

[0117] 1.2 wt% of 4-methylene-(4-diphenylamine)-bis(2,6-di-tert-butylphenol), 0.6 wt% of isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (component D);

[0118] 0.03 wt% 5-methylbenztriazole methylene C 12 -C 14 Tertiary alkyl amines (component E);

[0119] 0.2 wt% friction modifier, namely C4-C 12 A mixture of alkyl borate esters and potassium tetraborate (component F);

[0120] 0.002 wt% of perfluoropolyether modified polysiloxane antifoaming agent (component G);

[0121] 4.3 wt% Evonik V12-095 viscosity index enhancer, 70.018 wt% PAO 4, and 17.50 wt% adipate base oil (component H). The sum of the above components is 100 wt%.

[0122] The test results of Example 3 are shown in Table 5.

[0123] Table 5 Test Results

[0124]

[0125]

[0126]

[0127] Table 5 shows that the outstanding features of composition (Ⅲ) are its good electrochemical performance, good mechanical protection performance, excellent synchronizer durability and clutch friction stability, good thermal conductivity and material compatibility. It is particularly suitable for pure electric vehicles or hybrid electric vehicles with wet multi-ratio reduction gearboxes containing synchronizers and clutches, and can also improve the transmission efficiency of the reduction gearbox.

[0128] Of course, the present invention may have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A lubricating oil composition, comprising, based on 100% of the total weight of the lubricating oil composition: 3-7 wt% ashless dispersant, 0.05-0.3 wt% detergent, 0.7-1.5 wt% anti-wear agent, 1.5-4 wt% antioxidant, 0.01-0.1 wt% corrosion inhibitor, 0.2-0.6 wt% friction modifier, 0.001-0.003 wt% antifoaming agent, balance base oil; The ashless dispersant comprises a mixture of Mannich ashless dispersant and anti-wear dispersant; The Mannich ashless dispersant has the structure shown in Formula I: In Formula I, R1 is selected from H, hydroxyl group, C1-C 12 Hydrocarbon group, aromatic group, n is 2-6; The anti-wear dispersant has the structure shown in Formula II: In Formula II, R2 is selected from isobutyl, isopentyl, isohexyl, isoheptyl, isooctyl, and isononyl, and m is 2-6.

2. The lubricating oil composition according to claim 1, wherein, The molecular weight of PIB is 900-2500.

3. The lubricating oil composition according to claim 1, wherein, Based on a total weight of 100%, the composition of the lubricating oil composition includes: 3.6-5.4 wt% ashless dispersant, 0.1-0.3 wt% detergent, 0.8-1.5 wt% anti-wear agent, 1.5-2.5 wt% antioxidant, 0.01-0.05 wt% corrosion inhibitor, 0.2-0.4 wt% friction modifier, 0.002-0.003 wt% antifoaming agent, balance base oil.

4. The lubricating oil composition according to claim 1, wherein, In Formula I, R1 is selected from hydroxyl and methyl.

5. The lubricating oil composition according to claim 1, wherein, The mass ratio of the Mannich ashless dispersant to the anti-wear dispersant is 1:(0.1-0.2).

6. The lubricating oil composition according to claim 5, wherein, The mass ratio of the Mannich ashless dispersant to the anti-wear dispersant is 1:0.

2.

7. The lubricating oil composition according to claim 1, wherein, The anti-wear agent includes C 12- C 14 A mixture of tertiary alkyl amines, ammonium alkyl phosphates, and dodecyl phosphites.

8. The lubricating oil composition according to claim 7, wherein, The alkyl phosphate ammonium salts include dodecyl dihexyl phosphate and / or dodecyl butyl hexyl phosphate.

9. The lubricating oil composition according to claim 7, wherein, The C 12- C 14 The tertiary alkyl amines account for 0.05-0.2% of the total mass of the lubricating oil composition.

10. The lubricating oil composition according to claim 7, wherein, The mass ratio of the alkyl phosphate ammonium salt to the dodecyl phosphite is (0.1-0.25):

1.

11. The lubricating oil composition according to claim 1, wherein, The antioxidant comprises a mixture of phenolic amine antioxidants and phenolic ester antioxidants; the phenolic amine antioxidants also contain hindered phenolic and diphenylamine functional groups.

12. The lubricating oil composition according to claim 11, wherein, The phenolic antioxidants include 4-methylene-(4-diphenylamine)-2,6-di-tert-butylphenol and / or 4-methylene-(4-diphenylamine)-bis(2,6-di-tert-butylphenol).

13. The lubricating oil composition according to claim 11, wherein, The phenolic ester antioxidant includes isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

14. The lubricating oil composition according to claim 11, wherein, The mass ratio of the phenolic amine antioxidant to the phenolic ester antioxidant is 1:(0.25-0.5).

15. The lubricating oil composition according to claim 14, wherein, The mass ratio of the phenolic amine antioxidant to the phenolic ester antioxidant is 1:0.

5.

16. The lubricating oil composition according to claim 1, wherein, The corrosion inhibitor includes 5-methyltriazole methylene C. 12 -C 14 One or more of the following: tert-alkyl primary amines, 5-methylbenztriazole methylene dodecyl primary amines, and 5-methylbenztriazole methylene tetradecyl primary amines.

17. The lubricating oil composition according to claim 1, wherein, The friction modifier includes C4-C. 12 A mixture of alkyl borate esters and potassium tetraborate.

18. The lubricating oil composition according to claim 17, wherein, The potassium tetraborate accounts for 10% of the mass fraction of the friction modifier.

19. The lubricating oil composition according to claim 1, wherein, The base oil includes one or more of the following: viscosity index improver of dispersible PAM with a molecular weight of 30,000-100,000; API Group I 150BS mineral base oil; polyalphaolefin; and ester base oil.

20. The lubricating oil composition according to claim 19, wherein, The mass ratio of polyalphaolefin to ester base oil in the base oil is 4:

1.

21. The lubricating oil composition according to claim 1, wherein, The detergent includes calcium alkylbenzene sulfonate with a TBN of 300-320.

22. The lubricating oil composition according to claim 1, wherein, The antifoaming agent includes dimethyl silicone oil antifoaming agent and / or perfluoropolyether modified polysiloxane antifoaming agent.

23. The lubricating oil composition according to claim 1, wherein, The kinematic viscosity of the lubricating oil composition at 100°C is 5.0-6.0 mm. 2 / s.

24. A lubrication method comprising the lubricating oil composition according to any one of claims 1-23.

25. The lubrication method according to claim 24, wherein, This lubrication method is used in the gearbox of electric vehicles.

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