Lubricating oil, and preparation method and use thereof

Abstract

Provided in the present disclosure is a lubricating oil, comprising a base oil and an additive, wherein the additive comprises a first additive, a second additive and a third additive; the mass of the first additive is 1-10% of the mass of the lubricating oil; the first additive is an extrusion anti-wear agent; the mass of the second additive is 0.01-1% of the mass of the lubricating oil; the second additive is a friction modifier; the mass of the third additive is 1-10% of the mass of the lubricating oil; and the third additive is a viscosity index improver.

Description

A lubricating oil, its preparation method and its uses

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411692877.1, filed in China on November 22, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure pertains to the field of lubricating oil technology, and particularly relates to a lubricating oil and its uses. Background Technology

[0004] Early electric vehicles typically used general-purpose motors—composed of bearings and parts from the traditional gasoline-powered vehicle transmission system. However, in newer electric vehicles, to achieve a compact transmission structure with fewer transmission components, and to minimize power loss, reduce wear, and cool friction pairs, the motor and mechanical transmission components have gradually adopted an integrated drive system. The drive and transmission systems of electric vehicles are evolving from general-purpose to specialized systems. This presents new challenges to the cooling, insulation, and corrosion resistance of lubricants. Products that can adapt to more complex working environments and have greater compatibility will be the future development trend of automotive lubricants.

[0005] Currently used lubricant technologies are all generic formulations from additive companies (such as Lubrizol, Infineum, and Afton) or lubricant companies (such as Exxon Mobil, Shell, Castrol, and FUCHS). These generic formulations only address material compatibility and copper corrosion, lacking specific formulations for traditional electric drive lubricants designed to improve gear shaft protection, cooling, and efficiency. Summary of the Invention

[0006] In view of this, the technical problem to be solved by this disclosure is to provide a lubricating oil with a low coefficient of traction friction and high cooling performance, and its application.

[0007] This disclosure provides a lubricating oil, including a base oil and additives;

[0008] The additives include a first additive, a second additive, and a third additive;

[0009] The mass of the first additive is 1% to 10% of the mass of the lubricating oil; the first additive is an extrusion anti-wear agent;

[0010] The second additive is present in an amount of 0.01% to 1% of the mass of the lubricating oil; the second additive is a friction modifier.

[0011] The third additive is present in an amount of 1% to 10% of the mass of the lubricating oil; the third additive is a viscosity index improver.

[0012] In some embodiments, the viscosity range of the base oil is 2.0~20.0 mmHg at KV100℃. 2 / s and / or KV40℃: 10~50mm 2 / s.

[0013] In some embodiments, the base oil comprises a first polyalphaolefin and a second polyalphaolefin;

[0014] The viscosity range of the first polyalphaolefin is 1.5–3 mm at 100 KV. 2 / s; the viscosity range of the second polyalphaolefin is 3~5mm at KV100℃. 2 / s;

[0015] And / or, the additives include elements S, P, B, Ca, and Si;

[0016] The additives contain 500–2000 ppm of element S, 100–300 ppm of element P, 10–100 ppm of element B, 100–200 ppm of element Ca, and less than 10 ppm of element Si.

[0017] In some embodiments, the mass ratio of the first polyalphaolefin to the second polyalphaolefin is 20-50:40-70.

[0018] In some embodiments, the first polyalphaolefin is selected from SPECTRASYN 2 and / or DURASYN 162;

[0019] And / or, the second polyalphaolefin is selected from one or more of SPECTRASYN MAX 3.5, DURASYN 136 and DURASYN 133.

[0020] In some embodiments, the first additive is selected from... 35790 35750 and One or more of 35701;

[0021] And / or, the second additive is selected from... 35791 and / or 5760;

[0022] And / or, the third additive is selected from polymethacrylate viscosity index improvers.

[0023] In some embodiments, the third additive is selected from Viscoplex 3-195;

[0024] And / or, the additives may further include one or more of the following: extreme pressure additives, anti-wear additives, friction-reducing additives, antioxidants, corrosion inhibitors, metal passivators, dispersants, detergents, and defoamers.

[0025] In some embodiments, the lubricating oil has one or more of the properties of (1) to (14):

[0026] (1) Flash point ≥ 180℃;

[0027] (2) Pour point ≤ -40℃;

[0028] (3) Kinematic viscosity at 100℃: 3~5mm2 / s;

[0029] (4) Kinematic viscosity at 40℃: 12.0~15.0 mm2 / s;

[0030] (5) -40℃ Brinell viscosity: ≤1500mPa·s;

[0031] (6) GB / T12579-90 Foam Properties: Unit: ml / ml

[0032] 24℃, 25 / 0;

[0033] 93.5℃, 50 / 0;

[0034] After 24℃, 25 / 0;

[0035] (7) Thermal conductivity: ≥0.13W / m·K at 80℃;

[0036] (8) Specific heat capacity: ≥2.0 J / g·K at 80℃;

[0037] (9) KRL shear stability after 192h at 60℃ test: KV100≤15%, KV40≤5%;

[0038] (10) Evaporation loss at 150℃ for 1 hour ≤5%;

[0039] (11) The copper corrosion grade coefficient at 150℃ for 3 hours is selected from 1A or 1B;

[0040] (12) FZG A10 / 16.6R / 90 at 100℃: ≥7;

[0041] (13) 80h, 80KN, 7.5rpm, 80℃ FE8 bearing wear ≤20mg;

[0042] (14) 200h, 60KN, 750rpm, 100℃ FE8 bearing pitting ≥200h.

[0043] This disclosure also provides a method for preparing the above-mentioned lubricating oil, comprising the following steps:

[0044] The base oils are mixed, and under stirring and heating conditions, the first additive, the second additive, and the third additive are added to the mixed base oils to obtain a lubricating oil.

[0045] This disclosure also provides an electric drive system including the aforementioned lubricating oil.

[0046] This disclosure also provides a vehicle including the above-described electric drive system.

[0047] This disclosure provides a lubricating oil comprising a base oil and additives; the additives include a first additive, a second additive, and a third additive; the first additive comprises 1% to 10% of the mass of the lubricating oil; the first additive is an extrusion anti-wear agent; the second additive comprises 0.01% to 1% of the mass of the lubricating oil; the second additive is a friction modifier; the third additive comprises 1% to 10% of the mass of the lubricating oil; the third additive is a viscosity index improver. Compared with the prior art, the lubricating oil provided by this disclosure is a low-viscosity fluid and a low traction coefficient fluid, which can effectively enhance the gear shaft protection capability, improve cooling and heat dissipation performance, and enhance the efficiency of electric drive transmission. It can provide efficiency advantages and gear shaft protection advantages for vehicle transmission systems, and has a significant improvement effect on cooling and heat dissipation. Attached Figure Description

[0048] Figure 1 shows the molecular structure of polyalphaolefin base oil;

[0049] Figure 2 shows the detection results of the traction coefficient COF in Examples 1-3 and Comparative Examples 1-3 of this disclosure. Detailed Implementation

[0050] The technical solutions of this disclosure will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0051] Because electric vehicles have more complex systems, integrating a large number of electronic components, the demands on lubricants in their motor systems are much more stringent. Therefore, electric vehicle lubricants face numerous challenges in terms of chemical and physical performance. First, transmission fluid must maintain excellent oxidation stability under the high temperatures generated by the high-speed operation of the motor, while simultaneously providing efficient heat dissipation. Second, it needs to provide excellent cooling capacity. Lower viscosity and a thinner oil film result in better heat dissipation, which is beneficial to the motor, but a relatively thin oil film is detrimental to the protection of gears and bearings within the reducer. This poses a challenge to the viscosity index of the lubricant. Third, good electrochemical performance is crucial. To improve the high and low temperature performance of the lubricant and its protection of gears, some active elements added to the lubricant (such as sulfur and phosphorus) can corrode copper wires, thus placing higher demands on the compatibility of the lubricant with electrical components. Therefore, lubricant formulation research must simultaneously consider high and low temperature performance, gear protection, compatibility with electrical components, conductivity control, and other aspects to increase the durability of the transmission fluid and extend oil change intervals.

[0052] To address the aforementioned problems, this disclosure provides a lubricating oil comprising a base oil and additives; the additives include a first additive, a second additive, and a third additive; the first additive comprises 1% to 10% of the mass of the lubricating oil; the first additive is an extrusion anti-wear agent; the second additive comprises 0.01% to 1% of the mass of the lubricating oil; the second additive is a friction modifier; the third additive comprises 1% to 10% of the mass of the lubricating oil; the third additive is a viscosity index improver.

[0053] In this disclosure, the viscosity range of the base oil is preferably 2.0~20.0 mm at KV100℃. 2 / s and / or KV40℃: 10~50mm 2 / s; In some embodiments, the KV100℃ of the base oil is preferably 2.0–10.0 mm. 2 / s, more preferably 3.0 to 5.0 mm 2 / s, and more preferably 3.5–4.0 mm 2 / s, the optimal value is 3.8 to 3.85 mm. 2 / s.

[0054] In this disclosure, the base oil is preferably a polyalphaolefin (PAO). The molecular structure of the PAO base oil is shown in Figure 1. As can be seen from Figure 1, the characteristics of the PAO molecular structure are regular molecular chains, long carbon chain main chains, and few branches. According to molecular dynamics, branches intensify the atomic motion in the polymer chain, thereby reducing thermal conductivity. The long main chain and few branches give PAO high heat transfer performance, enabling it to maintain stable lubrication performance at high temperatures, effectively separating contact surfaces, reducing friction, and minimizing wear.

[0055] In one embodiment of this disclosure, the base oil comprises a first polyalphaolefin and a second polyalphaolefin; wherein the viscosity of the first polyalphaolefin is in the range of 1.5–3 mm at KV100°C. 2 / s, more preferably 1.5~2.5mm at KV100℃ 2 / s, and more preferably KV100℃1.5~2mm 2 / s, the optimal value is 1.7~1.8mm at KV100℃. 2 / s; In the embodiments provided in this disclosure, SPECTRASYN 2 and / or DURASYN 162 are specifically used as the first polyalphaolefin for illustration; The viscosity range of the second polyalphaolefin is 3-5 mm at 100°C. 2 / s, more preferably 3~4.5mm at 100℃. 2 / s, and more preferably KV100℃3~4mm 2 / s, the optimal value is 3.5~4mm at KV100℃. 2 / s; In the embodiments provided in this disclosure, one or more of SPECTRASYN MAX 3.5, DURASYN 136 and DURASYN 133 are specifically used as examples; The mass ratio of the first polyalphaolefin to the second polyalphaolefin is preferably 20-50:40-70, more preferably 20-30:60-70, even more preferably 25-30:60-65, and most preferably 29-31:60-63; In some embodiments provided in this disclosure, the mass ratio of the first polyalphaolefin to the second polyalphaolefin is specifically 29:62.16, 30.76:60.4 or 29.76:61.4.

[0056] In one embodiment of this disclosure, the additive includes elements S, P, B, Ca, and Si; wherein the content of element S in the additive is 500–2000 ppm, the content of element P is 100–300 ppm, the content of element B is 10–100 ppm, the content of element Ca is 100–200 ppm, and the content of element Si is less than 10 ppm.

[0057] In some embodiments provided in this disclosure, the additive includes a first additive, a second additive, and a third additive; the first additive is preferably 1% to 10% of the mass of the lubricating oil, more preferably 2% to 8%, even more preferably 2% to 6%, even more preferably 4% to 5%, and most preferably 4.5%; the first additive is an extrusion anti-wear agent; the second additive is preferably 0.01% to 1% of the mass of the base oil, more preferably 0.01% to 0.5%, even more preferably 0.02% to 0.2%, even more preferably 0.02% to 0.1%, even more preferably 0.02% to 0.08%, and most preferably 0.04% to 0.06%; the second additive is a friction modifier; the third additive is preferably 1% to 10% of the mass of the base oil, more preferably 2% to 8%, even more preferably 2% to 6%, even more preferably 4% to 5%, and most preferably 4.3% to 4.5%; the third additive is a viscosity index improver.

[0058] In some embodiments, the first additive in this disclosure is selected from the Hitech3 series of additives, more preferably... 35790 35750 and One or more of 35701.

[0059] In some embodiments, the second additive in this disclosure is selected from Hitech3 series additives and / or Hitech5 series additives, more preferably... 35791 and / or 5760.

[0060] In some embodiments, the third additive described in this disclosure is selected from polymethacrylate viscosity index improvers, more preferably Viscoplex 3-195.

[0061] This disclosure enables the lubricating oil to form a soft film on the metal surface by adding the above-mentioned additives, which has a low coefficient of friction, reduces friction loss, and improves transmission efficiency.

[0062] In another embodiment provided in this disclosure, the additive further includes one or more of extreme pressure additives, anti-wear additives, friction-reducing additives, antioxidants, corrosion inhibitors, metal passivators, dispersants, detergents, and defoamers.

[0063] In some embodiments, the extreme pressure additive is an additive that can form a high-melting-point chemical reaction film with the metal surface under high temperature and high pressure boundary lubrication conditions, and is an additive that can play a lubricating role under the condition of oiliness agent failure; extreme pressure additives can be divided into several categories such as organosulfur compounds, organophosphorus compounds, chlorides and organometallic salts, preferably including, but not limited to, one or more of phosphate esters, thiophosphate esters and phosphate ester amine salts; the mass of the extreme pressure additive can be 0.1% to 5% of the mass of the base oil, and can be selected according to the type added.

[0064] In some embodiments, anti-wear additives are high-tech lubricant additives. Commonly used anti-wear agents in lubricants include sulfur-based anti-wear agents, phosphorus-based anti-wear agents, sulfur-phosphorus anti-wear agents, halogen-based anti-wear agents, organometallic anti-wear agents, and boron-based anti-wear agents. These can reduce engine wear and increase engine power, and are therefore also known as engine maintenance agents or powerful repair agents. They can extend the service life of engine oil, save fuel, and improve power. The mass of the anti-wear additive can be 0.1% to 5% of the mass of the base oil, and can be selected according to the type added.

[0065] In some embodiments, friction-reducing additives are mainly used to reduce friction and wear between mechanical parts, thereby extending the service life of mechanical equipment, reducing maintenance frequency and downtime, lowering maintenance costs, and improving production efficiency. The friction-reducing additives described in this disclosure may be one or more of nano-copper (Cu), zinc oxide (ZnO), and aluminum oxide (Al2O3). The mass of the friction-reducing additive may be 0.1% to 5% of the mass of the base oil, and may be selected according to the type added.

[0066] In some embodiments, the antioxidant may be selected from one or more of alkylated diphenylamine, N-phenyl-α-naphthylamine, shielding phenol, and phenolic esters. For example, it may be selected from one or more of dibutyldiphenylamine, dioctyldiphenylamine, butyl / octyldiphenylamine, bis(dodecyl)diphenylamine, bis(pentyl)diphenylamine, N-phenyl-α-naphthylamine, 2,6-di-tert-butyl-p-cresol, and 2,6-di-tert-butyl-4-hydroxyphenylpropionate. Common commercial brands include T534, T531, T501, etc. The antioxidant is preferably 0.5% to 3% of the base oil mass, and can be selected according to the type added.

[0067] In some embodiments, the corrosion inhibitor is an additive that can effectively slow down the corrosion rate of metal, and may be one or more of dialkyl dithiophosphates, sulfonates, esters, and organophosphates, such as zinc dialkyl dithiophosphate (ZnDDP), petroleum sulfonates, synthetic sulfonates, sorbitol monoester of oleate, pentaerythritol monoester of oleate, dodecenyl succinate half ester, lanolin, mono- or di-tridecyl phosphate dodecyloxypropyl isopropanolamine salt, and alkyl phosphate imidazoline; the corrosion inhibitor is preferably 0.1% to 5% of the base oil mass, and may be selected according to the type added.

[0068] In some embodiments, the primary function of metal passivators is to protect the metal parts on the machine surface, preventing rust and corrosion upon contact with lubricating oil. Metal passivators form a protective film on the metal surface, preventing the erosion of oxygen and moisture, reducing friction and wear, and protecting the machine's operating efficiency and lifespan. Metal passivators are typically compounds containing sulfur, phosphorus, nitrogen, or other non-metallic elements, and their main varieties include benzotriazole derivatives and thiadiazole derivatives. Common metal passivators used in lubricating oils in China include T551 and T561. The preferred mass of the metal passivator is 0.1% to 3% of the base oil mass, and the choice can be made depending on the type added.

[0069] In some embodiments, the dispersant is an ashless dispersant, which may be polyisobutylene succinimide and / or boronized polyisobutylene succinimide. For example, monoisobutylene succinimide, diisobutylene succinimide, high molecular weight polyisobutylene succinimide, and boronized diisobutylene succinimide may be selected. Common commercial brands include T151, T154, T161, T154B, etc.

[0070] In some embodiments, detergents are chemicals that clean and keep engine parts clean, and their functions can be categorized into four aspects: acid neutralization, solubilization, dispersion, and washing. Commonly used detergents fall into five main categories: sulfonates, alkylphenol sulfides, alkyl salicylates, thiophosphates, and naphthenates.

[0071] In some embodiments, the defoamer may be one or more of silicone oil defoamers, organosilicon defoamers, and surfactant defoamers, and may be selected according to factors such as the type of base oil of the lubricating oil, operating temperature, and operating environment.

[0072] According to this disclosure, the lubricating oil has one or more of the properties of (1) to (15):

[0073] (1) Flash point ≥ 180℃;

[0074] (2) Pour point ≤ -40℃;

[0075] (3) Kinematic viscosity at 100℃: 3~5mm2 / s;

[0076] (4) Kinematic viscosity at 40℃: 12.0~15.0 mm2 / s;

[0077] (5) -40℃ Brinell viscosity: ≤1500mPa·s;

[0078] (6) GB / T12579-90 Foam Properties: Unit: ml / ml

[0079] 24℃, 25 / 0;

[0080] 93.5℃, 50 / 0;

[0081] After 24℃, 25 / 0;

[0082] (7) Thermal conductivity: ≥0.13W / m·K at 80℃;

[0083] (8) Specific heat capacity: ≥2.0 J / g·K at 80℃;

[0084] (9) KRL shear stability after 192h at 60℃ test: KV100≤15%, KV40≤5%;

[0085] (10) Evaporation loss at 150℃ for 1 hour ≤5%;

[0086] (11) The copper corrosion grade coefficient at 150℃ for 3 hours is selected from 1A or 1B;

[0087] (12) FZG A10 / 16.6R / 90 at 100℃: ≥7;

[0088] (13) 80h, 80KN, 7.5rpm, 80℃ FE8 bearing wear ≤20mg;

[0089] (14) 200h, 60KN, 750rpm, 100℃ FE8 bearing pitting ≥200h.

[0090] The lubrication effect of lubricating oil between mechanical parts can be mainly classified into three types: boundary lubrication, mixed lubrication, and fluid lubrication. In boundary lubrication, the speed is very low, and the lubricating oil film thickness is insufficient to completely separate the two surfaces. Surface roughness plays a dominant role, and the properties of additives have a significant impact on friction. Compared to boundary lubrication, in mixed lubrication, the thickness of the lubricating oil film gradually increases, but there is still direct contact between the surfaces. The coefficient of friction begins to decrease with increasing speed or decreasing load. In fluid lubrication, once the lubricating oil film is sufficient, it can completely separate the two surfaces, avoiding direct contact. The fluidity of the lubricating oil is needed to improve lubrication, thus reducing the coefficient of friction with increasing speed. The lubricating oil formulation provided in this disclosure may be attributed to providing lower friction and traction through boundary lubrication, mixed lubrication, and / or elastohydrodynamic lubrication, reducing frictional losses, improving transmission efficiency, and consequently improving gear transmission protection, motor cooling, and drive unit efficiency.

[0091] In summary, the present disclosure, through the combination of the above components, enables the lubricating oil to have a low coefficient of friction, which helps to reduce friction loss, enhances the protection capability of gear shafts, improves cooling and heat dissipation performance, and improves the efficiency of electric drive transmission. It can provide efficiency advantages for vehicle transmission systems and has a significant improvement effect on cooling and heat dissipation.

[0092] This disclosure also provides a method for preparing the above-mentioned lubricating oil, comprising: mixing base oils, and adding a first additive, a second additive and a third additive to the mixed base oils under stirring and heating conditions to obtain the lubricating oil.

[0093] The stirring speed is preferably 30 to 150 rpm; the heating temperature is preferably 50°C to 70°C.

[0094] This disclosure also provides an electric drive system including the aforementioned lubricating oil.

[0095] This disclosure also provides an electric vehicle including the electric drive system described above.

[0096] To further illustrate this disclosure, the following describes in detail a lubricating oil and its uses, in conjunction with embodiments.

[0097] All reagents used in the following examples are commercially available.

[0098] Examples and Comparative Examples

[0099] Preparation process: Add the base oil from the formula (as shown in Table 1), start stirring (speed range 80 rpm), start heating to 60℃, add the first additive, the second additive and the third additive, continue stirring and start circulation; after QC inspection is qualified, turn off the stirring / heating and circulation process.

[0100] The percentages in Table 1 are all mass percentages.

[0101] Table 1 Lubricating oil formulation

[0102] The performance of the lubricating oils obtained in the examples and comparative examples was tested, and the results are shown in Table 2; the test results of the traction coefficient COF of Examples 1-3 and Comparative Examples 1-3 are shown in Figure 2.

[0103] Table 2 Performance test results of lubricating oil

[0104] In Table 2, the CLTC operating condition efficiency is based on the operating condition efficiency of Comparative Example 1 to illustrate the degree of increase.

[0105] As shown in Table 2, the lubricating oil provided in this disclosure has a low traction coefficient, which can reduce friction loss, thereby effectively enhancing the gear shaft protection capability, improving cooling and heat dissipation performance, and increasing the efficiency of electric drive transmission.

[0106] The above description is only a preferred embodiment of this disclosure. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principles of this disclosure, and these improvements and modifications should also be considered within the scope of protection of this disclosure.

Claims

1. A lubricating oil, wherein, Including base oils and additives; The additives include a first additive, a second additive, and a third additive; The mass of the first additive is 1% to 10% of the mass of the lubricating oil; the first additive is an extrusion anti-wear agent; The second additive is present in an amount of 0.01% to 1% of the mass of the lubricating oil; the second additive is a friction modifier. The third additive is present in an amount of 1% to 10% of the mass of the lubricating oil; the third additive is a viscosity index improver.

2. The lubricating oil according to claim 1, wherein, The viscosity range of the base oil is 2.0~20.0 mm at KV100℃. 2 / s and / or KV40℃: 10~50mm 2 / s; And / or, the additives include elements S, P, B, Ca, and Si; The additives contain 500–2000 ppm of element S, 100–300 ppm of element P, 10–100 ppm of element B, 100–200 ppm of element Ca, and less than 10 ppm of element Si.

3. The lubricating oil according to claim 2, wherein, The base oil comprises a first polyalpha olefin and a second polyalpha olefin; The viscosity range of the first polyalphaolefin is 1.5–3 mm at 100 KV. 2 / s; the viscosity range of the second polyalphaolefin is 3~5mm at KV100℃. 2 / s.

4. The lubricating oil according to claim 3, wherein, The mass ratio of the first polyalphaolefin to the second polyalphaolefin is 20-50:40-70.

5. The lubricating oil according to claim 3, wherein, The first polyalphaolefin is selected from SPECTRASYN 2 and / or DURASYN 162; And / or, the second polyalphaolefin is selected from one or more of SPECTRASYN MAX 3.5, DURASYN 136 and DURASYN 133; And / or, the third additive is selected from polymethacrylate viscosity index improvers.

6. The lubricating oil according to claim 1, wherein, The first additive is selected from 35790、 35750 and One or more of 35701; And / or, the second additive is selected from... 35791 and / or 5760； And / or, the third additive is selected from Viscoplex 3-195.

7. The lubricating oil according to claim 1, wherein, The lubricating oil has one or more of the properties of (1) to (14): (1) Flash point ≥ 180℃; (2) Pour point ≤ -40℃; (3) Kinematic viscosity at 100℃: 3~5mm2 / s; (4) Kinematic viscosity at 40℃: 12.0~15.0 mm2 / s; (5) -40℃ Brinell viscosity: ≤1500mPa·s; (6) GB / T12579-90 Foam Properties: Unit: ml / ml 24℃，25 / 0； 93.5℃，50 / 0； After 24℃, 25 / 0; (7) Thermal conductivity: ≥0.13W / m·K at 80℃; (8) Specific heat capacity: ≥2.0 J / g·K at 80℃; (9) KRL shear stability after 192h at 60℃ test: KV100≤15%, KV40≤5%; (10) Evaporation loss at 150℃ for 1 hour ≤5%; (11) The copper corrosion grade coefficient at 150℃ for 3 hours is selected from 1A or 1B; (12) FZG A10 / 16.6R / 90 at 100℃: ≥7; (13) 80h, 80KN, 7.5rpm, 80℃ FE8 bearing wear ≤20mg; (14) 200h, 60KN, 750rpm, 100℃ FE8 bearing pitting ≥200h.

8. A method for preparing the lubricating oil according to claim 1, wherein, Includes the following steps: The base oils are mixed, and under stirring and heating conditions, the first additive, the second additive, and the third additive are added to the mixed base oils to obtain a lubricating oil.

9. An electric drive transmission system, wherein, This includes the lubricating oil according to any one of claims 1 to 7 or the lubricating oil prepared by the preparation method according to claim 8.

10. A vehicle, wherein, Includes the electric drive transmission system as described in claim 9.

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