Lubricating composition suitable for transmission system of pure electric commercial vehicle and application of lubricating composition

Abstract

The invention relates to the technical field of lubricating oil, in particular to a lubricating composition suitable for a transmission system of a pure electric commercial vehicle and application of the lubricating composition. The lubricating composition comprises the following components in percentage by weight: 60%-95% of base oil, 2%-20% of a viscosity index improver, 0.5%-2% of an extreme pressure agent, 0.1%-3% of an anti-wear agent, 0.1%-0.5% of a metal deactivator, 0.1%-2% of a pour point depressant, 0.05%-3% of a clearing agent, 1%-10% of a dispersing agent and 0.01%-2% of a defoaming agent. The lubricating composition disclosed by the invention has good antifriction property, sintering resistance, excellent wear resistance and high-temperature copper sheet protection capability, and is suitable for a transmission system of a pure electric commercial vehicle.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil technology, and more specifically to a lubricating composition suitable for the transmission system of pure electric commercial vehicles and its application. Background Technology

[0002] Pure electric passenger vehicles have achieved a three-in-one integration of motor, electronic control, and reducer, with lubricating oil capable of simultaneously lubricating the transmission system and cooling the power system. Pure electric commercial vehicles, limited by unsprung mass, spatial layout, and the technical challenges of integrating electronic control, cannot achieve this three-in-one integrated system. Currently, most pure electric commercial vehicles use a two-in-one integrated system of transmission and motor, and their lubrication primarily employs separate lubrication and cooling methods for the transmission and power systems.

[0003] Traditional internal combustion engine commercial vehicle transmission systems employ hypoid gears, requiring lubricants with excellent extreme pressure properties. This typically involves adding large amounts of sulfur-containing extreme pressure additives to prevent seizing under high-speed impact loads, but this also introduces the problem of strong corrosion to copper plates. Pure electric commercial vehicle transmission systems are gradually shifting towards helical or spur gears, appropriately reducing the load on the gears. However, due to vehicle weight and load, as well as reduced lubricant viscosity, good extreme pressure properties are still required. Simultaneously, the increasing speed of electric motors and energy recovery lead to higher lubricant temperatures, necessitating lubricants that reduce corrosion of metallic copper at high temperatures.

[0004] Therefore, there is a current need for a lubricating composition for the transmission system of pure electric commercial vehicles that can improve the protection capability of high-temperature copper sheets, while reducing the friction between metal parts and having good sintering resistance and excellent wear resistance.

[0005] No research has been found on lubricants for the transmission systems of pure electric commercial vehicles.

[0006] Therefore, it is essential to develop a lubricating composition suitable for the transmission system of pure electric commercial vehicles that can solve the above-mentioned technical problems and its application. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a lubricating composition and its application for the transmission system of pure electric commercial vehicles, which has good friction reduction, sintering resistance, excellent wear resistance, and high-temperature copper sheet protection capabilities.

[0008] This invention is achieved through the following technical solutions:

[0009] A lubricating composition suitable for the transmission system of pure electric commercial vehicles, comprising the following components in weight percentages:

[0010]

[0011] In some embodiments of the present invention, the base oil may be one of mineral oil or synthetic oil, specifically one or more of Group II base oil, Group III base oil, or synthetic base oil, preferably polyalphaolefin synthetic base oil, ester base oil, or natural gas synthetic oil. The kinematic viscosity of the base oil (single base oil) at 100°C is between 2 cst and 10 cst, preferably between 2 cst and 6 cst, and the amount of base oil added is between 60% and 95%, preferably 80% and 95%.

[0012] In some embodiments of the present invention, the viscosity index improver may be at least one of polyisobutylene, polymethacrylate, ethylene-propylene copolymer and styrene polyester, preferably polymethacrylate, the structural formula of which is shown in formula (1):

[0013]

[0014] Where R1 is C1-C 20 alkyl groups, preferably C 12 -C 14 The alkyl group; Y is an alkyl group or a nitrogen-containing polar group. The viscosity index improver is added in an amount between 2% and 20%, preferably between 5% and 12%, and more preferably between 1% and 10%.

[0015] In some embodiments of the present invention, the extreme pressure agent is selected from alkyl polysulfides as shown in formula (2), wherein X is 2-5 and R2 is C1-C2. 12 The extreme pressure agent contains alkyl groups or hydrocarbon groups containing benzene rings, and the amount of the extreme pressure agent added is between 0.5% and 2%, preferably between 1% and 2%.

[0016]

[0017] In some embodiments of the present invention, the anti-wear agent is selected from at least one of phosphate ester ammonium salt, phosphate ester, and thiophosphate ester, the structure of phosphate ester ammonium salt is shown in formula (3), and the structure of phosphate ester or thiophosphate ester is shown in formula (4).

[0018]

[0019] Where R3 is C2-C 18 alkyl groups, preferably C 10 -C 14 The alkyl group; R4 is H or C2-C 18 The alkyl group is preferably H or a C4-C8 alkyl group; R5 is a C2-C8 alkyl group. 18 alkyl groups; R6 is C2-C 18The alkyl group, phenyl group, or hydrocarbon group containing a benzene ring is present; when W and Z are selected from O, it is a phosphate ester; when at least one of W and Z is selected from S, it is a thiophosphate ester. One of W and Z is S, or both are S. When one of W and Z is selected from S, the other is selected from O. The amount of the anti-wear agent is between 0.1% and 3%, preferably between 0.1% and 2%, more preferably between 0.3% and 1%.

[0020] In some embodiments of the present invention, the lubricating composition contains thiadiazole and its derivatives or methylbenzotriazole and its derivatives as metal passivating agents. One metal passivating agent may be used alone or multiple metal passivating agents may be used, with the amount being between 0.1% and 0.5%, preferably between 0.1% and 0.3%.

[0021] In some embodiments of the present invention, the pour point depressant may be one or more of polymethyl methacrylate, polyacrylate, and vinyl acetate / trans-butene diacetate copolymer, and its dosage is between 0.1% and 2%, preferably between 0.1% and 1%.

[0022] In some embodiments of the present invention, the lubricating composition contains calcium alkylbenzene sulfonate, calcium salicylate, or calcium alkylphenol sulfide as a detergent. One or more of these can be used as detergents, and the amount used is between 0.05% and 3%, preferably between 0.5% and 1%.

[0023] In some embodiments of the present invention, the lubricating composition contains polyisobutylene succinimide or boron phosphated polyisobutylene bissuccinimide as a dispersant, and one or more of them can be used as a dispersant, with an amount between 1% and 10%, preferably between 1% and 5%.

[0024] In some embodiments of the present invention, the lubricating composition contains polydimethylsiloxane or a random copolymer of ethyl acrylate, 2-ethylhexyl acrylate, and vinyl n-butyl ether as a defoamer. One or more of these can be used as a defoamer, and the amount used is between 0.01% and 2%, preferably between 0.01% and 1%.

[0025] The present invention also relates to the application of the above-described lubricating composition in the transmission system of pure electric commercial vehicles.

[0026] The beneficial effects of this invention are:

[0027] This invention relates to a lubricating composition suitable for the transmission system of pure electric commercial vehicles. It possesses excellent friction-reducing properties, resistance to sintering, and superior anti-wear properties, as well as high-temperature copper strip protection. The lubricating composition is formed by combining base oils, viscosity index improvers, extreme pressure agents, anti-wear agents, metal passivators, pour point depressants, detergents, dispersants, and defoamers. To achieve the above objectives, this invention carefully selects the base oils, additive components, and their dosages in the lubricating oil composition. By appropriately reducing the proportion of extreme pressure agents and increasing the proportion of metal passivators, the high-temperature copper protection capability of the lubricating composition is improved. The compounding of extreme pressure agents, anti-wear agents, and other additives gives the oil excellent friction-reducing properties, resistance to sintering, and superior anti-wear properties, meeting the lubrication requirements of pure electric commercial vehicle transmission systems. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0029] Example

[0030] The formulations for Examples 1-3 are shown in Table 1.

[0031] Table 1 Formulations of Examples 1-3

[0032]

[0033] The details of each component in Table 1 are as follows:

[0034] O-1: Natural gas synthetic base oil, with a kinematic viscosity of 20 cst at 40°C and 4.3 cst at 100°C.

[0035] O-2: Group II mineral base oil, with a kinematic viscosity of 37 cst at 40°C and 6.5 cst at 100°C.

[0036] O-3: Polyalphaolefin synthetic base oil, with a kinematic viscosity of 19 cst at 40°C and 4.1 cst at 100°C.

[0037] O-4: Isooctanol adipate synthetic base oil, kinematic viscosity at 40°C 27 cst, kinematic viscosity at 100°C 5.4 cst.

[0038] V-1: Non-dispersed polymethyl methacrylate viscosity index improver, poly-(methyl methacrylate-co-dodecyl methacrylate), weight average molecular weight 100,000.

[0039] V-2: Non-dispersed polymethacrylate viscosity index improver, poly-(methyl methacrylate-co-dodecyl methacrylate), weight average molecular weight 50,000.

[0040] V-3: Dispersible polymethacrylate viscosity index improver, poly-(decyl methacrylate-co-N-tert-nonylacrylamide), weight average molecular weight 50,000.

[0041] E-1: Di-tert-butyl trisulfide.

[0042] E-2: Dibenzyl disulfide.

[0043] A-1: Tetradecyl phosphate dodecylamine salt.

[0044] A-2: Trimethylbenzene phosphate.

[0045] A-3: Nonylated diphenyl thiophosphate.

[0046] M: N,N-Di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine.

[0047] P: Polymethacrylate.

[0048] D: Superalkaline calcium hexadecyl salicylate with an alkalinity of 295 mg KOH / g.

[0049] A-5: Boron-phosphated polyisobutylene bis(succinimide) with a boron content of 0.85% and a phosphorus content of 0.65%.

[0050] A-6: Polydimethylsiloxane.

[0051] A-7: A random copolymer of ethyl acrylate, 2-ethylhexyl acrylate, and vinyl n-butyl ether, purchased from Afton Chemical Corporation, item number [item number missing]. 2030.

[0052] A lubricating composition suitable for the transmission system of pure electric commercial vehicles is implemented according to the following steps:

[0053] Step 1. Weigh each raw material according to the proportions in Table 1;

[0054] Step 2. Add base oil (mineral oil and synthetic oil), viscosity index improver, pour point depressant and defoamer to the reactor. Heat the reactor to 70°C at a heating rate of 5°C / min and stir at a stirring rate of 180 r / min. After the base oil, viscosity index improver, pour point depressant and defoamer are homogeneous, mixture A is obtained.

[0055] Step 3. Add extreme pressure agent, anti-wear agent, metal passivator, detergent, and dispersant to mixture A. Control the temperature of the reactor at 50°C with a heating rate of 5°C / min. Stir the mixture evenly at a stirring rate of 100 r / min. Stop stirring after it becomes homogeneous to obtain mixture B. After sampling and analysis, the lubricating composition for the transmission system of pure electric commercial vehicles is obtained.

[0056] The formulations for comparative examples 1-5 are shown in Table 2:

[0057] Table 2 Formulations of Comparative Examples 1-5

[0058]

[0059]

[0060] A-4: Dodecyl phosphate.

[0061] The preparation methods of Comparative Examples 1-5 are the same as those of Examples 1-3.

[0062] The test results of the oils blended using Examples 1-3 and Comparative Examples 1-5 are shown in Tables 3-5.

[0063] Table 3 Test results of Examples 1-3

[0064]

[0065] Table 4 shows the test results of Comparative Examples 1-3.

[0066]

[0067] Table 5 shows the test results of Comparative Examples 4-5.

[0068]

[0069]

[0070] High-temperature copper strip corrosion test: The copper strip corrosion test method specified in GB / T 5906 is applied, and the test is conducted at an oil temperature of 150℃ for 3 hours. In this test, the lower the discoloration level of the copper strip, the better the resistance to copper strip corrosion.

[0071] SRV Sintering Test: According to the extreme pressure performance test method for lubricating oil specified in NB / SH / T 0882, sintering tests were conducted on each lubricating composition using a ball-and-disc reciprocating friction testing machine (steel ball diameter 10mm, disk diameter 24mm, disk thickness 7.9mm). Under conditions of oil temperature 100℃, frequency 50Hz, and amplitude 2mm, friction was first applied at 50N for 30s, followed by friction at 100N for 15min. Afterward, the load was increased by 100N every 2min, and the moment sintering occurred was taken as the sintering load.

[0072] SRV Anti-wear Test: According to the method for determining the anti-wear performance of lubricating oils given in NB / SH / T 0847, the anti-wear composition was tested using a ball-disc reciprocating friction testing machine (steel ball diameter 10mm, disk diameter 24mm, disk thickness 7.9mm). Under the conditions of oil temperature 100℃, frequency 50Hz, and amplitude 1mm, the lubricating composition was first rubbed with 50N for 30s, then rubbed with a 400N load for 120min. The volume lost on the disk was taken as the wear volume, and the average coefficient of friction under 400N load for 15min was taken as f. 15 The average coefficient of friction under a 400N load for 30 minutes is taken as f. 30 The average coefficient of friction under a 400N load for 90 minutes is taken as f. 90 The average coefficient of friction under a load of 400N for 120 minutes is taken as f. 120 .

[0073] The experimental results show that Examples 1-3 have good sintering resistance, excellent wear resistance and high-temperature copper sheet protection ability, while maintaining the stability of the friction coefficient and reducing the friction between metal parts. Example 2 has the best effect.

[0074] When viscosity levels are comparable, the base oil and viscosity index improver have little effect on the extreme pressure and anti-wear properties of the oil. Therefore, when comparing the examples with the comparative examples, the amount of base oil was not controlled to be consistent, resulting in slight differences.

[0075] Compared to Comparative Example 1, Example 1 reduced the amount of extreme pressure agent E-1 and increased the amount of metal passivator M. As a result, the high-temperature copper sheet protection capability (150°C, 3h) decreased from 4a to 1b. This indicates that appropriately reducing the proportion of extreme pressure agent and increasing the proportion of metal passivator in the lubricating composition can effectively improve the high-temperature copper protection capability. It should be noted that, under similar viscosity levels, the amount of base oil has a relatively small impact on the extreme pressure and anti-wear properties of the oil. Therefore, when comparing Example 1 and Comparative Example 1, the base oil amount was not controlled to be consistent, resulting in a small difference.

[0076] Compared with Comparative Examples 4 and 5, Example 2 used a combination of anti-wear agents A-1 and A-2 instead of using anti-wear agents A-1 or A-2 alone. In the SRV anti-wear test, the wear volume of Example 2 was lower than that of Comparative Examples 4 and 5. The coefficient of friction of Example 2 remained at a low level and remained stable over time, which was better than that of Comparative Examples 4 and 5. The test results show that the use of phosphate ester amine salt and phosphate ester can effectively improve the anti-wear properties of oil and keep the coefficient of friction at a low and stable level.

[0077] Compared with Comparative Example 2, Example 3 replaced extreme pressure agent E-1 with extreme pressure agent E-2 and anti-wear agent A-4 with anti-wear agent A-3, while keeping the total amount of extreme pressure agent and anti-wear agent unchanged. As a result, in the SRV anti-wear test, the wear volume of Example 3 was lower than that of Comparative Example 2. The coefficient of friction of Example 3 remained at a low level and remained stable with the increase of time, which was better than Comparative Example 2. The test results show that the use of dibenzyl disulfide and thiophosphate can improve the anti-wear and friction reduction properties of oil.

[0078] Compared to Comparative Example 3, Example 2 controlled the addition of extreme pressure agent E-1 within an appropriate ratio. The results showed that in the SRV sintering test, the sintering load of Example 2 was 1500 N, while that of Comparative Example 3 was 900 N, indicating that Example 2 was superior to Comparative Example 3. Simultaneously, in the SRV anti-wear test, Example 2 exhibited a lower wear volume and maintained a consistently low coefficient of friction, which remained stable over time. This demonstrates that controlling the addition of the extreme pressure agent within an appropriate ratio, along with the formulation of suitable anti-wear agents, can give the oil excellent extreme pressure properties, anti-wear properties, and friction-reducing properties simultaneously.

[0079] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A lubricating composition suitable for the transmission system of pure electric commercial vehicles, characterized in that, The components include the following components by weight percentage:

2. The lubricating composition according to claim 1, characterized in that, The base oil includes one or more of Group II base oil, Group III base oil, and synthetic base oil, and the kinematic viscosity of the base oil at 100°C is between 4 cst and 10 cst. The synthetic base oil includes one or more of polyalphaolefin synthetic base oil, ester base oil, and natural gas synthetic oil.

3. The lubricating composition according to claim 1, characterized in that, The viscosity index improver includes at least one of polyisobutylene, polymethacrylate, ethylene-propylene copolymer and styrene polyester, wherein the structure of the polymethacrylate is shown in formula (1): Where R1 is C1-C 20 The alkyl group; Y is an alkyl group or a nitrogen-containing polar group.

4. The lubricating composition according to claim 3, characterized in that, R1 is C 12 -C 14 alkyl groups.

5. The lubricating composition according to claim 1, characterized in that, The extreme pressure agent is selected from alkyl polysulfides as shown in formula (2); Where X is 2-5, and R2 is C1-C 12 Alkyl groups or hydrocarbon groups containing benzene rings.

6. The lubricating composition according to claim 1, characterized in that, The anti-wear agent is selected from at least one of ammonium phosphate salt, phosphate ester, and thiophosphate ester. The structure of ammonium phosphate salt is shown in formula (3), and the structure of phosphate ester or thiophosphate ester is shown in formula (4). Wherein, R3 is C2-C 18 The alkyl group; R4 is H or C2-C 18 alkyl groups; R5 is C2-C 18 alkyl groups; R6 is C2-C 18 The alkyl group or phenyl group or hydrocarbon group containing a benzene ring; when W and Z are selected from O, it is a phosphate ester, and when at least one of W and Z is selected from S, it is a thiophosphate ester.

7. The lubricating composition according to claim 6, characterized in that, R3 is C 10 -C 14 The alkyl group; R4 is an H or C4-C8 alkyl group; when one of W and Z is selected from S, the other is selected from O.

8. The lubricating composition according to claim 1, characterized in that, The metal passivating agent includes at least one of thiadiazole and its derivatives or methylbenzotriazole and its derivatives; The pour point depressant includes one or more of polymethacrylate, polyacrylate, and vinyl acetate / trans-butene diacetate copolymer; The detergent includes at least one of calcium alkylbenzene sulfonate, calcium salicylate, and calcium alkylphenol sulfide. The dispersant includes at least one of polyisobutylene succinimide and boron phosphated polyisobutylene bissuccinimide; The defoamer includes one or two of the following: polydimethylsiloxane and ethyl acrylate, and a random copolymer of 2-ethylhexyl acrylate and vinyl n-butyl ether.

9. The lubricating composition according to claim 1, characterized in that, The components include the following components by weight percentage:

10. The application of the lubricating composition according to any one of claims 1-9 in the transmission system of a pure electric commercial vehicle.

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