Shock absorber oil for full-active hydraulic suspension system and preparation method of shock absorber oil

Abstract

The invention discloses shock absorber oil for a full-active hydraulic suspension system and a preparation method of the shock absorber oil. The shock absorber oil comprises the following components: the balance of poly-alpha-olefin synthetic oil; 10-15% of a viscosity index improver; 0.1 to 0.4% of a nanoparticle lubricant; 0.005 to 0.03% of a friction modifier; 0.5%-1.5% of a dispersing agent; 0.6%-2.0% of a sulfur-phosphorus type extreme pressure anti-wear agent; 0.1 to 0.8 percent of an antioxidant; and 30 to 100 ppm of a defoaming agent. The preparation method comprises the following steps: firstly, adding 10% of poly-alpha-olefin synthetic oil serving as a raw material into a production kettle, stirring and pre-heating; adding a nano-particle lubricant, stirring and dispersing at a high speed, adding a dispersant, carrying out grafting reaction at a constant temperature of 80 DEG C, adding a viscosity index improver, and continuously stirring at a constant temperature of 80 DEG C; and adding the residual poly-alpha-olefin synthetic oil, an antioxidant and other raw materials into the production kettle for reaction to obtain the shock absorber oil. The shock absorber oil has a high viscosity index and good high-temperature lubricating performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lubricating oil, and particularly relates to a shock absorber oil for a full-active hydraulic suspension system and a preparation method thereof. BACKGROUND

[0002] The full-active hydraulic suspension system has a hydraulic controllable shock absorber, wherein two cylinder cavities or damper chambers of a working cylinder of a given shock absorber are not only connected with each other through one or several applicable controllable dampers or throttle valves, but also have an externally connected high-performance gear pump for actively controlling the filling state of the cylinder cavities, and the hydraulic pressure can be introduced into the chassis as needed.

[0003] On the basis of the current more advanced semi-active electric CDC suspension, an internally meshed high-performance gear pump is externally connected, and through the powerful pumping capacity of the gear pump, the gear pump can supply and discharge oil to the shock absorber, solve the problem of fixed element parameters in the traditional passive suspension, and realize adaptive adjustment of parameters according to the sensing function of the sensor, further improve the adjustability of the vehicle, realize full-active control of the vehicle shock absorption, greatly improve the roll and pitch motion of the vehicle, and even realize the functions of bouncing and instantaneous lifting. The mode of the full-active hydraulic suspension system needs to rely on the high-voltage battery platform (400-800V) of the current hybrid and new energy vehicles, and the power consumption is relatively large, but with the development of new energy vehicles and batteries, it is the advanced technology of electric control suspension in the future. At present, it only exists in some high-end new energy vehicle models, but its performance is not bad, and it can effectively improve the smoothness and handling stability of the vehicle during driving. With the development of the suspension system and market demand, it has broad application prospects.

[0004] However, because of the high-power internally meshed gear pump attached in the system, the shock absorber oil not only needs to provide lubrication for the shock absorber, but also needs to provide lubrication for the high-power gear pump. However, the design and development of the traditional shock absorber oil do not consider the need to involve gear lubrication, which leads to the problem that if the traditional shock absorber oil is used in the full-active hydraulic suspension system, the lubrication performance of the gear is insufficient, resulting in abnormal noise, gear wear and other problems, greatly reducing the actual experience and service life of the system. The closed high-speed gear system is easy to cause the system to heat up too quickly, and the traditional shock absorber oil is easy to form oil sludge, causing abnormal damping. The existing gear oil, if used in the system, 1) the gear oil usually has a relatively large viscosity, which is not suitable for the shock absorber system and may cause the damping force value to be too high at room temperature. However, due to the low viscosity index, the high-temperature damping force decays seriously; 2) due to the insufficient adaptability of the oil product to high and low temperatures, the viscosity of the gear oil rises sharply (kinematic viscosity > 1000 cSt) below-30 DEG C, the flowability is poor, the damper response is delayed, and rapid shock absorption adjustment at low temperatures (such as the decrease in suspension comfort of a vehicle during cold start in a cold region) cannot be realized.

[0005] With the continuous development of intelligent suspension of new energy vehicles, the full active hydraulic suspension with excellent performance will be the main development direction of future suspension. However, there is no special shock absorber oil for full active hydraulic suspension at present. The oil demand of full active hydraulic suspension does not match the current conventional shock absorber oil, which makes the system prone to high temperature lubrication failure, abnormal noise caused by insufficient lubrication performance, and wear, increasing the difficulty of popularization of full active hydraulic suspension. SUMMARY

[0006] The present application aims at the deficiencies of the prior art, and provides a shock absorber oil suitable for full active hydraulic suspension system and a preparation method thereof. On the basis of the original excellent high and low temperature performance, anti-foaming performance and lubricating performance, the shock absorber oil needs to provide sufficient high pressure oil film support to prevent the direct contact of metal from causing biting and scratches under the condition of large pressure and low sliding speed of the gear system meshing; and needs to meet the oil demand of "high pressure wear resistance" and "precise pressure transmission" under various conditions of full active hydraulic suspension.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A shock absorber oil for full active hydraulic suspension system, the components are:

[0009] poly-alpha olefin synthetic oil in excess;

[0010] viscosity index improver 10-15%;

[0011] nanoparticle lubricant 0.1-0.4%;

[0012] friction modifier 0.005-0.03%;

[0013] dispersant 0.5%-1.5%;

[0014] sulfur-phosphorus type extreme pressure anti-wear agent 0.6-2.0%;

[0015] antioxidant 0.1-0.8%;

[0016] defoamer 30-100 ppm;

[0017] The above contents are all mass percentages, and the total of the components is 100%. Ppm is the mass content of one millionth.

[0018] Further, the poly-alpha olefin synthetic oil is a low viscosity poly-alpha olefin synthetic oil, the 100℃ kinematic viscosity of which is 1.5-6mm 2 / s, and the flash point is above 155℃; the commonly used poly-alpha olefin synthetic oil is poly-alpha olefin PAO3, PAO4, etc. of Mobil or Shanghai Doup, and the preferred poly-alpha olefin synthetic oil is PAO3 base oil with a flash point above 155℃.

[0019] Further, the viscosity index improver is selected from a dispersible polymethacrylate viscosity index improver, preferably a dispersible polymethacrylate viscosity index improver with a narrow molecular weight distribution and excellent shear stability, which has a dispersing function, is conducive to the dispersion of the nanoparticle lubricant in the system, and is also conducive to reducing the oil sludge generation of the product and prolonging the service life of the product.

[0020] Further, the nanoparticle lubricant is titanium dioxide particles with a particle size of 15-25 nm;

[0021] The lubrication mechanism thereof is 1) reducing the frictional resistance through a "micro bearing" effect; 2) under friction conditions, the nanoparticles form a smooth protective layer on the surface of the friction pair; and 3) filling the micro pits and damaged sites on the surface of the friction pair and playing a repairing role. The preferred addition amount is 0.15%, which can significantly improve the film-forming performance and gear repairing performance of the oil product while not significantly increasing the viscosity of the oil product. If the addition amount is too high, the viscosity of the oil product will be significantly increased, leading to poor low-temperature performance and easy aggregation and sedimentation. If the addition amount is too low, the lubrication effect will not be obvious.

[0022] Further, the dispersant can be selected from polyisobutylene succinimide, sodium dodecylbenzenesulfonate, and decyltrimethoxysilane, and can be one or a mixture of two or more thereof, and is preferably decyltrimethoxysilane. After hydrolysis, the silicon hydroxyl groups react with the surface hydroxyl groups of the nanometer titanium dioxide to form a covalent bond, so that the silane molecules are grafted to the surface of the filler to form a stable micellar structure, which is dispersed in the oil to prevent aggregation and sedimentation.

[0023] Further, the friction modifier can be selected from aluminum molybdate, molybdenum dialkyldithiophosphate, and molybdenum dialkyldithiocarbamate, and can be one or a mixture of two or more thereof, and is preferably aluminum molybdate. The unique lamellar structure of aluminum molybdate can rapidly form a stable protective film under friction and wear conditions, effectively reduce the friction coefficient, and improve the lubrication effect.

[0024] Further, the sulfur-phosphorus type extreme pressure anti-wear agent can be selected from triphenyl thiophosphate, ashless liquid butyl triphenyl thiophosphate, and ashless liquid dithiophosphate amine salt derivative, and can be one or a mixture of two or more thereof, and is preferably the ashless liquid dithiophosphate amine salt derivative, which has lower odor, has a dispersing function, and has better compatibility with nanometer titanium dioxide.

[0025] Further, the antioxidant can be selected from two kinds of antioxidants, namely, phenolic ester type ashless antioxidant and alkyl diphenylamine type high-temperature antioxidant. The phenolic antioxidant captures primary free radicals, and the amine antioxidant neutralizes oxidation acids to reduce paint film deposition. Considering the use requirements and cost, the best solution is 0.2% phenolic ester type ashless antioxidant and 0.3% alkyl diphenylamine type high-temperature antioxidant.

[0026] Further, the defoaming agent can be selected from: silicone defoaming agent, polyether defoaming agent, preferably the ratio of silicone defoaming agent and polyether defoaming agent is 1:3, which guarantees the defoaming performance and air release performance of the product.

[0027] A preparation method of a shock absorber oil of any one full active hydraulic suspension system, comprising the following steps:

[0028] (1) first, 10% of poly-alpha-olefin synthetic oil is used as raw material, added into a production kettle, stirred and preheated to above 40 DEG C;

[0029] (2) nano-particle lubricant is added, dispersed after high-speed stirring, then grafted reaction is carried out at constant temperature 80 DEG C, after stirring for a period of time, viscosity index improver is added to continue stirring at constant temperature 80 DEG C;

[0030] (3) then, the remaining poly-alpha-olefin synthetic oil, sulfur-phosphorus type extreme pressure anti-wear agent, friction modifier, antioxidant and defoaming agent are added into the production kettle, stirred at 75-80 DEG C for 30-35 min, and the shock absorber oil for full active hydraulic suspension system is obtained.

[0031] Beneficial effects:

[0032] The shock absorber oil for full active hydraulic suspension system prepared by the method is surface-chemically modified by using nano-particle lubricant and dispersant, and is supplemented by viscosity index improver, so that the dispersion type of the nano-particle lubricant is better, and the lubricating performance is better, specifically, small-particle-size titanium dioxide with a particle size of 15-25 nm is used, the titanium dioxide is surface-chemically modified by using decyl trimethoxysilane, and the dispersion type polymethacrylate viscosity index improver is supplemented, meanwhile, the addition of the dispersion type polymethacrylate viscosity index improver enables the shock absorber oil product to have ultrahigh viscosity index, good high-temperature lubricating performance and high-purity and low-oil-mud property, the shock absorber oil prepared by the method has lubricating performance suitable for full active hydraulic systems, can simultaneously meet the oil demand of the shock absorber and the gear pump lubricating system, and avoids the generation of damping failure and abnormal sound caused by the lubricating defects of traditional oil products for gear pumps. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the application are clearly and completely described below, obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0034] A special oil product for full active hydraulic suspension system, namely shock absorber oil, has the following mass percentage component:

[0035] Polyalphaolefin synthetic oil balance;

[0036] Viscosity index improver 10-15%;

[0037] Nanoparticle lubricant 0.1-0.4%;

[0038] Friction modifier 0.005-0.03%;

[0039] Dispersant 0.5%-1.5%;

[0040] Sulfur-phosphorus extreme pressure anti-wear agent 0.6-2.0%;

[0041] Antioxidant 0.1-0.8%;

[0042] Defoaming agent 30-100ppm;

[0043] The present invention will be further described below with reference to specific embodiments.

[0044] A method for producing a special oil for a fully active hydraulic suspension system comprises the following steps:

[0045] (1) First, add 10% poly-α-olefin synthetic oil as raw material into the production kettle, stir and preheat to above 40°C.

[0046] (2) Add the nanoparticle lubricant, stir and disperse at high speed for 20 minutes, then add the dispersant and keep the temperature at 80°C for grafting reaction. After stirring for 50 minutes, add the dispersed viscosity index improver and continue stirring at the constant temperature for more than 10 minutes.

[0047] (3) Add the remaining polyalphaolefin synthetic oil, sulfur-phosphorus extreme pressure anti-wear agent, friction modifier, antioxidant, and defoaming agent into the production kettle and stir at 75-80°C for 30-35 minutes to obtain the finished shock absorber oil.

[0048] The above-mentioned polyalphaolefin synthetic oil is polyalphaolefin PAO3 synthetic oil, the viscosity index improver is a dispersed polymethacrylate viscosity index improver, specifically Evonik viscosity index improver 6-054, produced by Evonik Degussa Romanx Oil Additives Co., Ltd., the nanoparticle lubricant - titanium dioxide with a particle size of 15-25nm is produced by Germany's Sachshalben Chemical Co., Ltd., the friction modifier is aluminum molybdenum tripolyphosphate, the dispersant is decyltrimethoxysilane, the sulfur-phosphorus extreme pressure anti-wear agent is an ashless liquid dithiophosphate amine salt derivative, the antioxidant is a compound of a phenolic ester ashless antioxidant (TK135) and an alkyl diphenylamine high-temperature antioxidant (L57), and the defoamer is a compound defoamer of a silicone defoamer and a polyether defoamer in a ratio of 1:3.

[0049] Example:

[0050]

[0051]

[0052] The content of each component is 100%, and the product is obtained by adding and stirring uniformly according to the specified steps in the production method.

[0053] Comparative Example 1:

[0054] This comparative example provides a special oil for a full-active hydraulic suspension system, and the preparation method is the same as that of Example 1, except that titanium dioxide particles with a particle size of 50-150 nm are used.

[0055] Comparative Example 2:

[0056] This comparative example provides a special oil for a full-active hydraulic suspension system, and the preparation method is the same as that of Example 1, except that no decyl trimethoxysilane is added.

[0057] The performance of the product is detected by using national or industry standard analysis methods, and the results are as follows:

[0058]

[0059]

[0060] From the data of the examples:

[0061] (1) The conventional shock absorber oil cannot meet the customer's demand for oil FZG index ≥10, and the problem of abnormal noise and wear of the gear system easily occurs. In the examples, decyl trimethoxysilane is used to modify and graft 15-25 nm titanium dioxide. Due to its small particle size and better dispersion uniformity, the lubrication effect is optimal in the FZG comparison experiment, and it can meet the user's demand, greatly reducing the occurrence of abnormal noise during use. As can be seen from Comparative Examples 1 and 2, large-particle-size nano titanium dioxide or titanium dioxide particles not modified by a dispersing agent have poor lubrication performance and are prone to agglomeration and sedimentation, affecting the end use.

[0062] (2) The uniformly dispersed nano TiO2 in the oil is more likely to adsorb on the surface of the friction pair to form a stable adsorption film. The presence of the adsorption film improves the lubrication conditions between the contact pairs, making the lubricating oil more easily enter the contact area, thereby increasing the oil film thickness. The FZG A20 / 8.3 / 90 test data are significantly improved compared to traditional shock absorber oils, which can well meet the gear lubrication of the full-active hydraulic system and prevent lubrication failure and abnormal noise.

[0063] (3) The viscosity of the traditional shock absorber oil at 150°C is 2.18 mm 2 / s, it is difficult to meet the high temperature lubrication of gear pump, the oil film thickness is insufficient at high temperature, and the problem of lubrication failure is easy to occur; the viscosity at-40℃ is also high, at low temperature, the pumping performance of oil and the adjustment ability of the system are affected. The poly-alpha olefin PAO3 synthetic oil is selected in the example, and the viscosity index modifier 6-054 of yingchuang is used to adjust, so that the viscosity index of the product reaches more than 300, and the high and low temperature performance of the product is ensured: the 150℃ viscosity of the oil is more than 3mm 2 / s, effectively guaranteeing the lubrication demand of the gear at high temperature; the low temperature-40℃ viscosity is less than 1200mm 2 / s, and the pour point of the product is-57℃, guaranteeing the normal operation of the system at low temperature environment.

[0064] (4) The product uses a compound defoaming agent, so that the product has excellent anti-foaming performance, so that the oil provides good lubrication and heat dissipation performance in the multi-directional operation of the damper damping hole and the internal meshing gear pump.

[0065] It can be seen that after the 15-25 nanometer particle size of silicon dioxide is modified and grafted by decyl trimethoxysilane, excellent lubrication performance is exhibited, which is suitable for the lubrication performance of full active hydraulic system, and can meet the oil demand of the damper and gear pump lubrication system at the same time, avoiding the generation of damping failure and abnormal sound caused by the lubrication defect of traditional oil for gear pump.

Claims

1. A shock absorber oil for a fully active hydraulic suspension system, characterized in that: The components are: Polyalphaolefin synthetic oil balance; Viscosity index improver 10-15%; Nanoparticle lubricant 0.1-0.4%; Friction modifier 0.005-0.03%; Dispersant 0.5%-1.5%; Sulfur-phosphorus extreme pressure anti-wear agent 0.6-2.0%; Antioxidant 0.1-0.8%; Defoaming agent 30-100ppm; The above contents are all percentages by mass, the sum of the components is 100%, and ppm is one part per million by mass.

2. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The polyalphaolefin synthetic oil is a low-viscosity polyalphaolefin synthetic oil with a kinematic viscosity of 1.5-6 mm at 100°C. 2 / s, flash point is above 155℃.

3. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The viscosity index improver is a dispersed polymethacrylate viscosity index improver.

4. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The nanoparticle lubricant is titanium dioxide particles with a particle size of 15-25 nm.

5. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The dispersant is one or more of polyisobutylene succinimide, sodium dodecylbenzenesulfonate, and decyltrimethoxysilane.

6. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The friction modifier is one or more of aluminum molybdenum tripolyphosphate, molybdenum dialkyl dithiophosphate, and molybdenum dialkyl dithiocarbamate.

7. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The sulfur-phosphorus extreme pressure anti-wear agent is one or more of triphenylthiophosphate, ashless liquid butyl triphenylthiophosphate, and ashless liquid dithiophosphate amine salt derivatives.

8. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The antioxidant is a mixture of a phenolic ester type ashless antioxidant and an alkyl diphenylamine type high temperature antioxidant.

9. The shock absorber oil for a fully active hydraulic suspension system according to claim 1, characterized in that: The defoamer is a compound defoamer consisting of an organosilicon defoamer and a polyether defoamer.

10. A method for preparing shock absorber oil for a fully active hydraulic suspension system according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) First, add 10% poly-α-olefin synthetic oil as raw material into the production kettle, stir and preheat to above 40°C; (2) Add the nanoparticle lubricant, stir and disperse at high speed, add the dispersant and keep the temperature at 80°C for grafting reaction, stir for a period of time, add the viscosity index improver and continue stirring at 80°C; (3) The remaining polyalphaolefin synthetic oil, sulfur-phosphorus extreme pressure anti-wear agent, friction modifier, antioxidant, and defoaming agent are then added to the production kettle and stirred at 75-80° C. for 30-35 minutes to obtain shock absorber oil for a fully active hydraulic suspension system.

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