Running-in oil special for transmission system and preparation method of running-in oil

Abstract

The invention relates to the technical field of running-in oil, in particular to running-in oil special for a transmission system and a preparation method of the running-in oil. The special running-in oil for the transmission system is prepared from the following components in parts by weight: 95 to 99 parts of blending base oil, 1.0 to 2.2 parts of an extreme pressure agent, 0.5 to 1.0 part of an anti-wear agent, 0 to 0.5 part of a friction improver, 0.1 to 0.3 part of a pour point depressant and 0.00001 to 0.00002 part of an organic silicon anti-foaming agent. The running-in oil special for the transmission system has appropriate low viscosity, good fluidity and viscosity-temperature property, can effectively reduce residues of the running-in oil in a gearbox, has good extreme pressure anti-wear performance and excellent anti-foaming performance, guarantees rapid running-in of the gearbox or a drive axle, reduces damage to tooth surfaces of parts, and improves the service life of the gearbox or the drive axle. The running-in oil provided by the invention has the advantages of improved subsequent vehicle operation efficiency, prolonged vehicle service life, and low production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of running-in oil, in particular to a special running-in oil for transmission system and a preparation method thereof. BACKGROUND

[0002] During the initial hundreds of kilometers of use of the vehicle, the gears and the gear ring in the transmission system are in the process of mutual running-in. Due to the existence of small machining marks on the surface of the parts, the process of mutual friction will introduce impurities into the lubricating oil, and at the same time, it will cause the running temperature to be too high, causing the quality of the oil to decrease, etc., thereby affecting the normal use of the lubricating oil. Running-in the gearbox and drive axle before driving can improve the surface topography of the parts, improve the carrying capacity, and make the vehicle enter a stable working state, thereby improving the service life and oil change mileage.

[0003] During the running-in period, the lubricating oil in the gearbox or drive axle will mix with the impurities such as wear debris generated by the mutual friction between the gears. After the running-in is completed, the waste oil cannot be completely discharged due to its high viscosity, which causes the oil quality to decrease after mixing with new oil, and thus adversely affects the gearbox and other components. Therefore, the running-in oil needs to have appropriate low viscosity. On the one hand, high viscosity will cause the oil film to be too thick, which reduces the running-in efficiency, and the decrease in flowability caused by high viscosity will also cause more waste oil to remain when the waste oil is discharged. On the other hand, too low viscosity will easily cause direct contact between the friction pairs, which will cause irreversible damage to the parts.

[0004] Chinese Patent Publication No. CN113913230A discloses a manual gearbox running-in oil and a preparation method thereof, which is composed of mineral base oil, viscosity index improver, pour point depressant, extreme pressure anti-wear agent, antioxidant, friction modifier, detergent dispersant, anti-rust agent and anti-foaming agent. It has excellent flowability, thermal oxidation stability, etc., and provides lubrication protection for the gearbox during the running-in process. However, the flowability of the above-mentioned running-in oil needs to be further improved, and the dosage of the additives is relatively high, which increases the production cost, and the extreme pressure anti-wear performance also needs to be further improved.

[0005] Therefore, it is necessary to develop a special running-in oil for transmission system and a preparation method thereof which can solve the above technical problems. SUMMARY

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a dedicated break-in oil for transmission systems and its preparation method. This break-in oil is used before a new vehicle is put into operation or after a major overhaul to break in the vehicle, bringing it into a stable operating state and extending its service life. The dedicated break-in oil for transmission systems of this invention has low viscosity and good fluidity, enabling thorough removal of waste oil. This break-in oil exhibits good extreme pressure anti-wear properties, good viscosity-temperature characteristics, and excellent anti-foaming properties, meeting the oil standards for gearbox factory break-in and performance testing while effectively extending the vehicle's oil change mileage and service life. Furthermore, this break-in oil is blended using low-cost base oils with a low dosage, reducing the cost of using break-in oil and offering good economic benefits.

[0007] This invention is achieved through the following technical solutions:

[0008] A special break-in oil for transmission systems, comprising, by weight, the following components: 95-99 parts of blending base oil, 1.0-2.2 parts of extreme pressure agent, 0.5-1.0 parts of anti-wear agent, 0-0.5 parts of friction modifier, 0.1-0.3 parts of pour point depressant, and 0.00001-0.00002 parts of silicone antifoaming agent.

[0009] Preferably, the blending base oil includes PCL150SN base oil and PCL4 base oil.

[0010] More preferably, the mass ratio of PCL150SN base oil to PCL4 base oil is 30.0%-30.6%: 69.4%-70.0%.

[0011] Preferably, the extreme pressure agent is any one or both of isobutylene sulfide and di-tert-butyl polysulfide.

[0012] Preferably, the anti-wear agent is any one of trialkyl dithiophosphate, tricresyl phosphate, n-butyl thiophosphate, or a mixture thereof.

[0013] Preferably, the friction modifier is any one of an organomolybdenum compound or an organoboroate.

[0014] Preferably, the pour point depressant is polymethacrylate.

[0015] Preferably, the organosilicon antifoaming agent is methyl silicone oil.

[0016] This invention also relates to a method for preparing the above-mentioned break-in oil for transmission systems, comprising the following steps:

[0017] 1) The base oil and pour point depressant are blended for the first time; then the silicone antifoaming agent is added and blended for the second time to obtain the break-in oil base oil;

[0018] 2) Add extreme pressure agent, anti-wear agent and friction modifier to the base oil of the running-in oil and stir to obtain the special running-in oil for the transmission system.

[0019] Preferably, the process parameters for the first mixing in step 1) are: mixing at 60-70℃ for 1.5-2 hours; and the process parameters for the second mixing are: mixing at 60-70℃ for 1.5-2 hours.

[0020] Preferably, the stirring process parameters in step 2) are: constant temperature stirring at 50-60℃ for 1.5-2 hours.

[0021] The beneficial effects of this invention are:

[0022] Compared with the prior art, the special break-in oil for transmission systems of the present invention has the following characteristics: 1. It is blended with low-viscosity base oil, has strong fluidity, and is conducive to the discharge of waste oil after break-in; 2. It has low dosage, low cost, and good economic benefits; 3. It has good extreme pressure anti-wear performance, can cope with high load conditions, has a wide range of applications, and is also suitable for vehicle transmission systems such as gearboxes and drive axles.

[0023] The break-in oil formulated for transmission systems according to this invention has suitable low viscosity, good fluidity, and viscosity-temperature characteristics, effectively reducing break-in oil residue in the gearbox. It also possesses excellent extreme pressure anti-wear properties and superior anti-foaming properties, ensuring rapid break-in of the gearbox or drive axle while minimizing damage to the gear surfaces of components. This improves subsequent vehicle operating efficiency and extends vehicle lifespan. The break-in oil formula of this invention has low production costs, excellent performance, and high economic benefits and application value. Attached Figure Description

[0024] Figure 1 The friction coefficient curves of the special break-in oil for transmission systems in Examples 1-4 and Comparative Examples 1 and 2 are obtained by the SRV test machine method. Detailed Implementation

[0025] 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.

[0026] To screen base oil components and additive components, this invention employs the following methods in the laboratory: kinematic viscosity test (GB / T265), low-temperature apparent viscosity test (GB / T 11145), pour point test (GB / T 3535), copper strip corrosion test (GB / T5096), anti-foaming test (GB / T 12579), and flash point test (GB / T 3536).

[0027] To evaluate the break-in oil, this invention employs the four-ball bearing capacity test method (GB / T 3142), the four-ball wear scar diameter test method (SH / T 0189), the SRV testing machine method (Q / SY 1495), and the FZG gear machine test (CEC L-84) for simulated evaluation.

[0028] In each embodiment, PCL150SN is named according to PetroChina's PCL base oil, which is a Group I base oil HVI150.

[0029] In each embodiment, PCL4 is named according to PetroChina's PCL base oil, which is Group III base oil VHVI4.

[0030] The trialkyl dithiophosphate structures used in each embodiment are as follows:

[0031]

[0032] Where R refers to octyl (-C8H) 17 ).

[0033] Example 1:

[0034] The preparation method of special break-in oil 1 for transmission systems includes the following steps:

[0035] 1) Weigh 30% PCL150SN, 68.1% PCL4, and 0.3% polymethyl methacrylate by mass percentage, add them to a mixing tank, and mix at 60°C for 2 hours; add 0.00001% methyl silicone oil, and continue mixing at 60°C for 2 hours to obtain the break-in oil base oil.

[0036] 2) Weigh 1.1% isobutylene sulfate and 0.5% trialkyl dithiophosphate by mass percentage and add them to the base oil of the running-in oil. Stir at 60°C for 2 hours to obtain the special running-in oil 1 for the transmission system. The evaluation results of the special running-in oil 1 for the transmission system are listed in Table 1.

[0037] Table 1 Evaluation Results of Special Break-in Oil for Transmission Systems

[0038]

[0039] Example 2:

[0040] The preparation method of the special break-in oil 2 for transmission systems includes the following steps:

[0041] 1) Weigh 29.9% PCL150SN, 67.8% PCL4, and 0.3% polymethyl methacrylate by mass percentage, add them to a mixing tank, and mix at 70°C for 1.5 hours; add 0.00001% methyl silicone oil, and continue mixing at 70°C for 1.5 hours to obtain the break-in oil base oil;

[0042] 2) Weigh 1.4% of sulfurized isobutylene and 0.6% of trialkyl dithiophosphate by mass percentage and add them to the base oil of the running oil. Stir at a constant temperature of 50°C for 1.5 hours to obtain the special running oil 2 for the transmission system.

[0043] Example 3:

[0044] The preparation method of the special break-in oil 3 for transmission systems includes the following steps:

[0045] 1) Weigh 30.0% PCL150SN, 68.1% PCL4, and 0.3% polymethyl methacrylate by mass percentage, add them to a mixing tank, and mix at 60°C for 2 hours; add 0.00001% methyl silicone oil, and continue mixing at 60°C for 2 hours to obtain the break-in oil base oil;

[0046] 2) Weigh 1.1% of di-tert-butyl polysulfide, 0.25% of tricresyl phosphate, and 0.25% of n-butyl thiophosphate by mass percentage and add them to the base oil of the running oil. Stir at a constant temperature of 60°C for 2 hours to obtain the special running oil for the transmission system 3.

[0047] Example 4:

[0048] The preparation method of the special break-in oil 4 for transmission systems includes the following steps:

[0049] 1) Weigh 29.8% PCL150SN, 67.8% PCL4, and 0.3% polymethyl methacrylate by mass percentage, add them to a mixing tank, and mix at 70°C for 1.5 hours; add 0.00001% methyl silicone oil, and continue mixing at 70°C for 1.5 hours to obtain the break-in oil base oil;

[0050] 2) Weigh 1.1% of sulfurized isobutylene, 0.5% of trialkyl dithiophosphate, and 0.5% of di(2-ethylhexyl) dithiophosphate molybdenum according to the mass percentage and add them to the base oil of the running oil. Stir at a constant temperature of 50°C for 1.5 hours to obtain the special running oil 4 for the transmission system.

[0051] Comparative Example 1: The only difference from Example 1 is the composition of the base oil used; PCL150SN was used instead. All other conditions were the same.

[0052] The preparation method of the special break-in oil 5 for transmission systems includes the following steps:

[0053] 1) Weigh 98.1% of PCL150SN and 0.3% of polymethyl methacrylate by mass percentage, add them to a mixing tank, and mix at 60°C for 2 hours; add 0.00001% of methyl silicone oil, and continue to mix at 60°C for 2 hours to obtain the break-in oil base oil.

[0054] 2) Weigh 1.1% of sulfurized isobutylene and 0.5% of trialkyl dithiophosphate by mass percentage and add them to the base oil of the running oil. Stir at a constant temperature of 60°C for 2 hours to obtain the special running oil 5 for the transmission system.

[0055] Comparative Example 2: The only difference from Example 1 is the composition of the base oil used; PCL4 was used instead. All other conditions were the same.

[0056] The preparation method of special break-in oil 6 for transmission systems includes the following steps:

[0057] 1) Weigh 98.1% PCL4 and 0.3% polymethyl methacrylate by mass percentage, add them to a mixing tank, and mix at 60°C for 2 hours; add 0.00001% methyl silicone oil, and continue to mix at 60°C for 2 hours to obtain the break-in oil base oil;

[0058] 2) Weigh 1.1% of sulfurized isobutylene and 0.5% of trialkyl dithiophosphate by mass percentage and add them to the base oil of the running oil. Stir at a constant temperature of 60°C for 2 hours to obtain the special running oil 6 for the transmission system.

[0059] To investigate the performance of this invention, the physicochemical properties of the transmission system-specific break-in oil prepared in the above embodiments were analyzed and bench simulation experiments were conducted. The results are shown in Table 2. The SRV friction and wear test results (100℃, 400N) are as follows: Figure 1 As shown.

[0060] Table 2 Main Properties and Performance of Break-in Oils for Transmission Systems

[0061]

[0062] The data in Table 2 shows that the special break-in oil formulation for transmission systems of the present invention has the following characteristics in terms of viscosity, extreme pressure anti-wear properties, and frictional properties:

[0063] 1. During the break-in period, the operating temperature inside the gearbox is higher than the normal operating temperature. Simultaneously, the break-in oil is in a cooling phase when waste oil is discharged. During both of these processes, the break-in oil needs to maintain a low viscosity to prevent an excessively thick oil film from affecting the break-in process and to ensure complete discharge of waste oil. The break-in oil formulated with this method has good viscosity-temperature characteristics, maintaining a low kinematic viscosity at both 100℃ and 40℃.

[0064] 2. The break-in process can improve the surface quality and tribological properties of the parts, bringing the gearbox into a stable, low-wear state. Simultaneously, it's necessary to protect the gears from damage during break-in, requiring the break-in oil to possess certain extreme pressure anti-wear properties. The dedicated break-in oil for transmission systems exhibits good load-bearing performance, with a small wear scar diameter in the four-ball wear test and a low coefficient of friction in the SRV test, demonstrating good extreme pressure anti-wear properties.

[0065] 3. Friction modifiers have excellent friction-reducing properties, improving the coefficient of friction between moving parts and increasing break-in efficiency. The bis(2-ethylhexyl)dithiophosphate molybdenum in transmission system-specific break-in oil 4 has a unique break-in mechanism, differing from the chemical break-in mechanism produced by sulfur and phosphorus elements in other break-in oils. During the break-in process, the MoS2 produced by decomposition can act as abrasive particles, simultaneously performing abrasive wear and improving break-in efficiency. For example... Figure 1 As shown in the friction coefficient curve, the friction coefficient fluctuates greatly, and the addition of friction modifiers reduces the corrosion resistance of the lubricating oil.

[0066] 4. A comparison between running oil 1 and running oil 3 shows that the sintering load of the formula of running oil 1 is significantly higher than that of running oil 3, and its anti-wear performance is better.

[0067] 5. Comparing break-in oil 1 with break-in oils 5 and 6, it can be seen that break-in oil 5, using only Group I base oil PCL150SN, resulted in a significant increase in kinematic viscosity, especially at 40℃, which affected the discharge of waste oil after cooling following break-in. On the other hand, using only Group III base oil PCL4 resulted in a lower viscosity, leading to a thinner oil film that was prone to rupture and wear upon tooth surface contact. Furthermore, Group III base oil PCL4 is expensive, resulting in low economic efficiency for the break-in oil.

[0068] 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 break-in oil for a driveline system, characterized in that, According to the weight parts, it is composed of 95-99 parts of blending base oil, 1.0-2.2 parts of extreme pressure agent, 0.5-1.0 parts of anti-wear agent, 0-0.5 parts of friction modifier, 0.1-0.3 parts of pour point depressant, 0.00001-0.00002 parts of organic silicon antifoam agent.

2. The break-in oil for a transmission system according to claim 1, characterized by, The blending base oil comprises PCL150SN base oil and PCL4 base oil.

3. The break-in oil for a transmission system according to claim 2, characterized by, The mass ratio of PCL150SN base oil and PCL4 base oil is 30.0%-30.6%:69.4%-70.0%.

4. The break-in oil for a transmission system according to claim 1, characterized by, The extreme pressure agent is any one or both of sulfurized isobutylene and di-tert-butyl polysulfide.

5. The break-in oil for a transmission system according to claim 1, characterized by, The anti-wear agent is any one or mixture of any combination of trialkyl dithiophosphate, trimethylphenyl phosphate, n-butyl thiophosphate.

6. The break-in oil for a transmission system according to claim 1, characterized by, The friction modifier is any one of organic molybdenum compound or organic borate.

7. The break-in oil for a transmission system according to claim 1, characterized by, The pour point depressant is polymethyl acrylate.

8. The break-in oil for a transmission system according to claim 1, characterized by, The organic silicon antifoam agent is methyl silicone oil.

9. The method of producing a running-in oil for a transmission system according to any one of claims 1 to 8, characterized in that, It comprises the following steps: 1) First blending of blending base oil and pour point depressant, then second blending of organic silicon antifoam agent, to obtain running-in oil base oil; 2) Adding extreme pressure agent, anti-wear agent and friction modifier to the running-in oil base oil and stirring, to obtain the special running-in oil for transmission system.

10. The method of claim 9, wherein, The process parameters of the first blending in step 1) are blending at 60-70℃ for 1.5-2h, and the process parameters of the second blending are blending at 60-70℃ for 1.5-2h.

11. The preparation method according to claim 9, characterized in that, The process parameters of the stirring in step 2) are constant temperature stirring at 50-60℃ for 1.5-2h. The process parameters of the stirring in step 2) are constant temperature stirring at 50-60℃ for 1.5-2h.

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