WO2010049439A1

WO2010049439A1 - Synthetic lubricant composition and use thereof

Info

Publication number: WO2010049439A1
Application number: PCT/EP2009/064190
Authority: WO
Inventors: Jörg Fahl; Rainer Petersen; Armin Sue; Andreas Lutz
Original assignee: Volkswagen Ag
Priority date: 2008-10-28
Filing date: 2009-10-28
Publication date: 2010-05-06
Also published as: DE102008043231A1

Abstract

The invention relates to a synthetic lubricant composition and to the use thereof, preferably for lubricating an active differential that has an acceleration stage and a double clutch, preferably comprising friction discs made of sintered materials. The lubricant composition according to the invention comprises at least 50% of a synthetic base oil and 0.03 to 5 wt % zinc dithiophosphate and 0.04 to 4 wt % magnesium sulfonate, wherein the composition includes a zinc content of 1000 to 2000 mg/kg, a phosphorous content of 3000 to 4000 mg/kg, a magnesium content of 2000 to 3500 mg/kg and a sulfur content of 2000 to 4000 mg/kg.

Description

description

Synthetic lubricant composition and its use

The invention relates to a synthetic lubricant composition and its use preferably for lubricating an active differential with an acceleration stage and a dual clutch, which preferably comprises friction plates made of sintered materials.

State of the art

From the automotive industry is known to use Reibschaltelemente for realizing operations or functions that require operation of the Reibschaltelemente in continuous slip at least for a certain time. This is the case, for example, with converter clutches and starting shift elements. In this case, there is a risk of damage in continuous slip operation due to the steeply rising surface temperature of the friction shift elements involved.

Active differentials for the individual distribution of the drive torque to the individual wheels are becoming increasingly important. By different distribution of the drive torque to the wheels, an improvement of traction, agility and driving stability is possible.

From DE 10 2006 008 236 A1, for example, a transmission device for the variable distribution of a torque to two output shafts is known. A corresponding transmission has been described in the local Fig. 3. The mechanical system consists essentially of a spur gear differential, an acceleration stage and a hydraulically operated double clutch. A spur gear differential is located in the driving gearbox and replaces the standard bevel gear differential. It is lubricated by the lubricant of the transmission. The other two main components are located in a separate housing with its own oil budget. The acceleration stage consists of two gear stages, each of which is designed as an internal external toothing. The ring gear with the two internal gears is mounted eccentrically. The coaxial input gear is connected to the differential carrier. The also coaxial output gear rotates about 10% faster relative to the mean wheel speed. This slightly higher speed will be on the common clutch basket passed the two multi-plate clutches. By operating one clutch at a time, torque can be transferred from the clutch basket to the right or left driven wheel. The clutches are controlled by the vehicle dynamics control.

These gearboxes place high demands on the lubricant. It must meet the following minimum requirements:

Low friction in the rolling bearings. The different requirements of grooved ball, needle, cylindrical roller and tapered roller bearings must be met.

Seal compatibility with static and dynamic seals

Wear protection in the two raceways (outer race)

Internal gears)

Compatibility with hydraulic components (pump, accumulator and valves), especially in the low and high temperature range), as the hydraulic unit is integrated in the gear unit and a common oil budget is available.

In addition to the above objects, in the new transmissions, e.g. known from DE 10 2006 008 236 A1, further requirements are met, which were not previously required. In particular, the requirements of the special mode of action of the multi-plate clutch are crucial here.

In previously common applications, multi-plate clutches are used in such a way that the clutch is actuated to produce a speed equality between two shafts, e.g. as a starting clutch or in automatic transmissions for switching individual translations. During the switching process, a power loss occurs in the clutch, which decreases as the differential speed decreases. In the closed state moment is still transmitted, but in that the differential speed is zero, there is no power loss.

In active differentials, in contrast, the clutch is constantly operated in the actuated state in the slip. A speed equality, ie a closing of the clutch must not occur, because then no statements about the actually transmitted torque are possible. This has the consequence; that upon actuation of the clutch constantly dissipated power in the frictional contact and thus in the fins and in the lubricant is initiated. This places the highest demands on the friction linings and on the thermal stability of the lubricant.

The system must be designed in such a way that the thermal limits of the individual components are not exceeded in the case of the usual customer-relevant load. In addition to the thermal stability of the lubricant, a high heat capacity and good thermal conductivity of the friction plates is of great importance. Therefore, in the running active differential sintered linings are preferably used, which have a higher heat capacity and better thermal conductivity than carbon linings.

The use of sintered linings is possible since relatively small relative speeds between the friction linings are present during use. At higher sliding speed, sintered linings, however, lead to a decrease in the coefficient of friction, which can lead to control problems in the form of oscillations of the friction torque. This therefore makes special demands on a lubricating fluid.

Description of the invention

It is therefore an object of the present invention to provide a lubricant composition which particularly meets the lubrication requirements for active differentials and coupling materials, e.g. Sintering / steel blades, which work in continuous slip, can suffice.

The following requirements are preferably placed on such a lubricant composition:

Maximum pressure in contact Sintered / steel lamella: 4-6 N / mm ² Coefficient of friction in contact: 0.09 to 0.1 l at sliding speeds of> 0.05 m / s and a pressure of 4 N / mm ² to 6 N / mm ² - Low drag losses in the multi-plate clutches up to approx. 1 m / s

relative speed

Increasing coefficient of friction up to approx. 0.6 m / s average relative speed Max. Power losses in the coupling up to 15 kW Max. Area output in friction contact up to 0.3 W / mm ² High heat capacity to dissipate the loss energy from the couplings High thermal load at temperatures up to 220 ⁰ C in frictional contact Good lubricity of hypoid gears.

The object could be achieved by a synthetic lubricant composition comprising at least 50% by weight of a synthetic base oil, preferably at least 80% by weight, with or without additive composition, and further comprising the following components:

0.03 to 5% by weight of zinc dialkyldithiophosphate and

0.04 to 4% by weight of magnesium sulfonate.

The composition according to the invention has a zinc content of 1000 to 2000 mg / kg, preferably 1200-1800 mg / kg, a phosphorus content of 3000 to 4000 mg / kg, preferably 3200-3800 mg / kg, a magnesium content of 2000 to 3500 mg / kg, preferably from 2500-3000 mg / kg, and a sulfur content of from 2000 to 4000 mg / kg, preferably from 2200 to 2800 mg / kg.

In addition to a base oil, the lubricant composition according to the invention is characterized in that it preferably comprises at least one additive which is selected from antioxidants, detergents, dispersants, flow improvers high-pressure abrasives (EP), friction modifiers, corrosion, rust and foam inhibitors and / or viscosity index improvers.

The lubricant composition of the invention is preferably used in oil-lubricated couplings:

under continuous slip conditions wherein the clutch is a dual clutch - a blade comprising sintered material and a blade comprising steel wherein the sintered material is a grit sintered material wherein the clutch is preferably a dual clutch (i.e., the clutch can serve 2 different output strands) at low sliding speeds and

- A - with swelling loading conditions.

Therefore, the lubricant composition of the present invention is preferably used in a method for lubricating an active differential having an acceleration stage and a dual clutch including friction plates of sintered materials by being added to the active differential.

base oils

The base oils include in particular mineral oils, synthetic oils and natural oils. Mineral oils are generally derived from petroleum or crude oil by distillation and / or refining and optionally other purification and refining operations. In general, a distinction is made between paraffin-based, naphthenic and aromatic fractions in crude oils or mineral oils, the terms paraffin-based fraction being longer-chain or highly branched isoalkanes and naphthenic fraction being cycloalkanes. In addition, mineral oils, depending on their origin and refinement, have different proportions of n-alkanes, isoalkanes with a low degree of branching, so-called monomethyl-branched paraffins, and compounds with heteroatoms, in particular O, N and / or S, which are attributed to polar properties , Natural oils are animal or vegetable oils, such as claw oils or jojoba oils.

For the purposes of the invention, synthetic base oils are used. They include, but are not limited to, organic esters such as diesters and polyol esters, polyalkylene glycols, polyethers, synthetic hydrocarbons, particularly Group III base oils, and polyolefins, of which polyalphaolefins (PAO) are preferred, silicone oils and perfluoroalkyl ethers. The base oils can also be used as mixtures and are often commercially available.

In principle, the base oil that can be used to provide the compositions of the invention as described herein can be any of the base oils in Groups I to V as specified in the American Petroleum Institute (API) Base Oil Interchange Ability Guidelines as well as being selected from gas-to-liquid base oils. The base oil groups Group I to V are as follows:

¹ Groups I to III are mineral oil base materials

The amount of base oil in the compositions may range from about 50 to 99.93 weight percent of the lubricant composition.

To alter the flow properties, the base oils are optionally added with so-called flow improvers (viscosity index (VI) improvers and pour point depressants), e.g. higher molecular weight thickener added. These are a series of long-chain polymers that improve dissolved in mineral oil, the viscosity-temperature behavior; i.e. they reduce the temperature dependence of the viscosity; at low temperatures they improve the flow behavior, and at high temperatures they cause a higher viscosity than without Vl improver. VI improvers are important ingredients in lubricating oils.

Hydro-cracking oils and synthetic oils based on polyalphaolefins (PAO) are preferably used according to the invention. Hydro-cracking oils are typically recovered from slack wax from dewaxing of the raffinates or from vacuum gas oil. They are also called HC synthesis oils. Starting product for the synthetic

Hydrocarbons, such as e.g. the PAO are gasoline-like hydrocarbons. According to the present invention, it is preferable to use a base oil of Group III hydrocracking oil and Group IV PAO.

The lubricating fluids typically contain various substances for the targeted improvement of certain properties. These additives (additives) serve, for example, to improve the load carrying capacity and wear protection (High-pressure and anti-wear additives), the foam behavior (foam inhibitors), the friction properties (friction modifier) and the oxidation and corrosion stability (oxidation inhibitors, metal passivators, rust inhibitors). Furthermore, dispersants and detergents are used as additives. An overview of the additives used in lubricating fluids is disclosed, for example, in Montier, RM and Orszulik, ST. : Chemistry and Technology of Lubricants (Springerverlag GmbH, 1997).

Preferred flow improvers in the context of the present invention are hydrogenated polystyrene-co-isoprene (HSI), ethylene-propylene copolymers (OCP), polyisobutylene (PIB), polyalkyl acrylates and methacrylates or their copolymers (PAMA), vinylpyrrolidone / methacrylate copolymers, Polyvinylpyrrolidone, polybutenes, olefin copolymers, styrene / acrylate copolymers, polyethers, alkylated naphthalene derivatives or mixtures thereof, more preferably PAMA is used.

In a preferred embodiment, the composition of the invention has a kinematic viscosity of 3.0 to 18.0 mm ² / s (centistokes) at 100 ⁰ C, preferably 4.0 to 10.0 mm ² / s.

Gear oils are described with SAE (Society of Automotive Engineers) grades that specify viscosity measurement temperatures, viscosity limits, and class assignments. When hot, the viscosity of the engine and gear oils is uniformly determined for all SAE classes at 100 ^° C.

More preferably, a lubricant composition is provided which

0.05 to 1 wt.% Zinc dithiophosphate and 0.1 to 0.4 wt.% Magnesium sulfonate.

In an alternative embodiment, a synthetic lubricant composition is composed so that it further contains on the basis of a synthetic base oil selected from a group III hydrocracking oil or based on PAO group IV and in addition to zinc dithiophosphate and magnesium sulfonate: flow improver (0 to 3 %) and / or dispersing agent (0 to 5%). In addition, the lubricant composition may optionally comprise 0.03-3.0% by weight of calcium sulfonates, preferably 0.1-0.3% by weight.

Particularly preferred compositions consist of base oil, zinc dithiophosphate and magnesium sulfonate, optionally in combination with at least one flow improver and / or dispersant (s).

Surprisingly, it has been found that the combination of this synthetic lubricant composition has excellent properties as a transmission oil for lubrication in a geared trivago system, preferably for lubricating an active differential with an acceleration stage and a dual clutch, which preferably comprises friction disks made of sintered materials.

Since, as already stated, in active differentials the clutch is always operated in slippage in the actuated state, a speed equality, ie a clutch closure, must not occur. The system of the active differential is designed in such a way that the thermal limits of the individual components are not exceeded in the case of the usual customer-relevant load. In addition to the thermal stability of the lubricant, a high heat capacity and good thermal conductivity of friction plates with sintered linings is ensured.

The advantageous interaction of the base oil and the additives used particularly preferably allow the use for the lubrication of multi-disc clutches of sintered material, preferably for friction discs made of scattered sintered materials, such as e.g. Hoerbiger HS 45.

The advantageous properties of the lubricant according to the invention require the addition of a balanced additive composition adapted to the base oil. According to the invention, this additive component contains, in addition to zinc dialkyldithiophosphate and magnesium sulfonate and optionally calcium sulfonate, compounds from the following groups: Anti-wear additives

Examples of anti-wear additives are: sulfur and / or phosphorus and / or halogen-containing compounds, e.g. sulfurized olefins and vegetable gels.

Metal salts of dialkyldithiophosphoric acids, e.g. Zinc dialkyldithiophosphates.

Furthermore, phosphorus compounds such as e.g. Trialkyl phosphates and tricresyl phosphates (TCP) used.

Further examples are chlorinated paraffins, alkyl and aryl di- and trisulfides,

Amine salts of mono- and dialkyl phosphates, amine salts of methylphosphonic acid, diethanolaminomethyltolyltriazole, di (2-ethylhexyl) aminomethyltolyltriazole, derivatives of 2,5-dimercapto-1, 3,4-thiadiazole, 3 - [(bis-isopropyloxy-phosphinothioyl) thio] - propionic acid ethyl ester, triphenylthiophosphate (triphenyl phosphorothioate), tris (alkylphenyl) phosphorothioate and mixtures thereof (eg tris (isononylphenyl) phosphorothioate), diphenylmonononylphenyl phosphorothioate, isobutylphenyl diphenylphosphorothioate, dodecylamine salt of 3-hydroxy-1,3-thiaphosphetane-3 oxide, trithiophosphoric acid-5,5,5-tris [isoac-tylacetati, derivatives of 2-mercaptobenzothiazole such as 1- [N, N-bis (2-ethylhexyl) aminomethyl-2-mercapto-1,3-benzthiazole, ethoxycarbonyl-5-octyl-dithiocarbamate can also be used as anti-wear additives in the context of the invention.

Antioxidants (antioxidants)

As antioxidant according to the invention preferably phenolic antioxidants are used.

Examples of phenolic antioxidants:

1. Alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert. butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-i-butylphenol, 2,6-di-cy-clopentyl-4- methylphenol, 2- (a-methylcyclohexyl) -4,6-dimethylphenol, 2,6-DI-octadecylW4-methylphenol, 2,4,6-tri-cyclohexylpheno [, 2,6-di-tert-butyl-4-methoxymethylphenol , 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6- (1'-methyl-undec-1'-yl) -phenol, 2,4-dimethyl-6- (1 '-methyl-heptadec-1'-yl) phenol, 2,4-dimethyl-6- (1'-methyl-tridec-1'-yl) -phenol and mixtures thereof. 2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-diisocyanate dodecylthiomethyl-4-nonylphenol.

3. Hydroquinones and alkylated hydroquinones, e.g. 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone, 2,5-di-tert-amyl-hydroquinone, 2,6-diphenyl-4-octadecyloxypheno [

2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyaniso], 3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyaniso] tert-butyl-4-hydroxyphenyl stearate, bis (3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

4. Hydroxylated thiodiphenyl ethers, e.g. 2,2'-thio-bis (6-tert-butyl-4-methylphenol), 2,2'-thio-bis (4-outyl-phenol), 4,4'-thio-bis (6- tert -butyl 3-methylphenol]), 4,4'-thio-bis (6-tert-butyl-2-methylphenol), 4,4'-thiobis- (3,6-di-sec-amylphenol), 4, 4'-bis (2,6-dimethyl-4-hydroxybhezyl) disulfide.

5. Alkylidene bisphenols, e.g. 2,2'-methylenebis (6-tert-butyl-4-methylphenol), 2,2'-methylenebis (6-tert-butyl-4-ethylpheno [), 2,2'-methylbenzyl) Methylene-bis- [4-methyl-6- (α-methylcyclohexyl) -phenol], 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,2'-

Methyl [enbis- (6-nony-4-methylphenol), 2,2'-methylenebis (4,6-di-tert-butylphenol), 2,2'-ethylidene-bis (4, 6-di-tert-butylphenol), 2,2'-ethylidene-bis (6-tert-butyl-4-isobutylphenol), 2,2'-methylene-bis-16- (α-methylbenzyl) -4-nony [phenol], 2,2'-methylenebis [6- (a, adimethylbenzyl) -4-nonylphenol], 4,4'-methylenebis (2,6-di-tert-butylphenol) , 4,4'-methylenebis (6-tert-butyl-2-naphthylphenol), 1, 1-bis (5-tert-butyl-4-hydroxy-2-methylphenyl) -butane, 2,6- Bis (3-t-butyl-5-methyl-2-hydroxybenzyl) -4-methylphenol, 1, 1, 3-tris (5-tert-butyl-4-hydroxy-2-methyl [phenyl] - butane, 1,1-bis (5-tert-butyl-4-hydroxy-2-methyl-phenyl) -3-n-dodecyne-mercaptobutane, ethyl niglycoi-bis- [3,3-bis- (3 ') tert-butyl-4'-hydroxyphenyl) -butyrate], bis (3-tert-butyl-4-hydroxy-5-methyl-phenyl) -dicyclopentadiene. Bis- [2- (3'-tert-butyl-2'-hydroxy-5'-methylbenzyl) -6-tert-butyl-4-methylphenyl] terephthalate, 1,1-bis ( 3,5-dimethyl-2-hydroxyphenyl (-butane), 2,2-bis (3,5-di-tert-butyl-4-hydroxyphnzyl) propane, 2,2-bis (5-tert-butyl 4-hydroxy-2-methylphenyl) -4-dodecylmercapto-betan, 1,1,5,5-tetra- (5-tert-butyl-4-hydroxy-2-methylphenol) -pentane.

6. O-, N- and S-benzyl compounds, eg 3,5,3 ', 5'-tetra-tert-butyl-4,4'-dihydroxydibenzyl ether, octadecyi-4-hydroxy-3,5- dimethyl benzyl mercaptoacetate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) amine, bis (4-tert-butyl-3-hydroxy-2,6-dimethyl-benzyl) dithioterephthalate, Bis- (3,5-di-tert-butyl-4-hydroxybenzyl) -sulFide, isooctyl-3,5-di-tert-butyl-4-hydroxybenzyl-mercaptoacetate. 7. Hydroxybenzylated malonates, eg dioctadecyl-2,2-bis- (3,5-di-tert-butyl-2-hydroxybenzy!) - ma [onate, di-octadecyl-2- (3-tert-butyl) 4-hydroxy-5-methylbenzyl) malonate, didodecylmercaptoethyl 2,2-bis (3,5-di-tert-butyl-4-hydroxybenzyl) malonate, di- [4- (1, 1, 3,3-tetramethylbutyl) -Phe-nyl] -2,2-bis (3,5-di-tert-but ^y l-4-hydroxybenzyl) malonate. 8. Hydroxybenzy [aromatics, eg 1, 3,5-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,4-bis (3, 5-di-tert-butyl-4-hydroxybenzyl) -2,3,5,6-tetramethylbenzene, 2,4,6-tris- (3,5-di-tert-butyl-4-hydroxy-benzyl) -phenol.

9. triazine compounds, for. B. 2,4-bis-octylmercapto-6- (3,5-di-tert-butyl-4-hydroxyanilino) -1,3,5-triazine, 2-octylmercapto-4,6-bis (3, 5-di-tert-butyl [-4-hydroxyanilino] -1, 3,5-triazine, 2-octylmercapto-4,6-bis (3,5-di-tert-butyl-4-hydroxyphenoxy) - 1, 3,5-triazine, 2,4,6-tris- (3,5-di-tert-butyl-4-hydroxyphenoxy) -1, 2,3-triazine, 1, 3,5-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 2,4,6-tris- (3,5-di-tert-butyl-4-hydroxyphenylethyl) -1,3,5-triazine, 1,3,5-tris- (3,5-di-tert. butyl-4-hydroxyphenylpropionyl) -hexahydro-1,3,5-triazine, 1,3,5-tris (S.δ-dicyclohexyl) -hydroxybenzyl isocyanurate.

10. Benzylphosphonates, e.g. Dimethyl 2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl-3,5-di-tert-butyl-4- hydroxybenzylphosphonate, dioctadecyl-δ-tert-butylm-hydroxy-S-methylbenzylphosphonate, Ca-salt of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid monoethyl ester. 1 1. Acylaminophenols, e.g. 4-Hydroxy-lauric acid anilide, 4-hydroxystearic acid anilide, N- (3,5-di-tert-butyl-4-hydroxyphenyl) -carbamic acid octyl ester.

12. esters of (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid with mono- or polyhydric alcohols, such as, for example, with methanol, methanol, octadecanol, 1,6-hexanediol, 1, 9- Nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thioliethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxyethyl) isocyanurate, N, N'-bis (hydroxyethyl) oxalic acid diamide, 3-thiaundecanol, 3 Thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl [-1-phospha-2,6,7-trioxabicyclo [2.2.2] octane.

13. esters of 8- (5-tert.-butyl-4-hydroxy-3-methylphenyl) -propane sols with monohydric or polyhydric alcohols, for example with methanol, ethanol, octadecanol, 1,6-hexanediol, 1, 9-nonanediol, ethylene glycol, 1, 2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxy) ethyl isocyanurate, N, N'-bis (hydroxyethyl) oxalic acid diamide, 3-thiaundecanol, 3-thiapentadecanol, tri- methylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo [2.2.2] octane

14. Esters of β- (3,5-dicyclohexyl-4-hydroxyphenyl) -propionic acid with monohydric or polyhydric alcohols, e.g. with methanol, ethanol, octadecanol, 1, 6-hexanediol, 1, 9-nonanediol, ethylene glycol, 1, 2-propanediol, neopentyl glycol, thiodiethylene glycol,

Diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxy) ethyl isocyanurate, N, N'-bis (hydroxyethyl) oxalic acid diamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha -2,6,7-triaxabicyclo [2.2.2] octane. 15. esters of 3,5-di-tert-butyl-4-hydroxyphenylacetic acid with monohydric or polyhydric alcohols, such as. With methanol, ethanol, octadecanol, 1,6-hexanediol, 1, 9-nonanediol, ethylene glycol, 1, 2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris (hydroxy) ethyl-isocyanuric urate, NJ, N'-bis (hydroxyethyl) oxalic acid diamide. 3-thiaundecanol, 3-thiapentadecanol, trimethylhexenediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-triox.abicyclo [2.2.2] octane.

16. Amides of (3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionic acid, for example N, N'-bis- (3,5-di-tert-butyl-4-hydroxyphenylprapionyl) - hexamethylenediamine, N, N'-bis- (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) trimethylenediamine, N, N'-bis- (3,5-di-tert-butyl-4-) hydroxyphenylpropionyl) hydrazine.

Examples of aminic antioxidants are, for example:

N, N'-di-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N, N'-bis (1, 4-dimethylpentyl) -p-phenylenediamine , N, N'-bis (1-ethyl-3-methyl-pentyl) -p-phenylenediamine, N, N'-bis (1-methyl-heptyl) -p-phenylenediamine, N, N'-dicyclohexyl p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N, N'-di- (naphthyl-2) -p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N- (1, 3-dimethyl-butyl) -N-phenyl-p-phenylenediamine, N- (1-methyl-heptyl) -N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4- (p-toluene-sulfonamido) -diphenylamine, N, N'-dimethyl-N, N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxy-diphenylamine, N-phenyl- 1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, eg, p, p'-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylamino-phenol, 4-nano-nanoyl-amino-phenol, 4 Dodecanoylaminophenol, 4-octadecanoylamino-phenol, di- (4-methoxyphenyl) -amine, 2,6-di-tert-butyl-4-dimethylamino-methylphenol, 2,4'-diamino-diphene ylmethane, 4,4'-diamino-diphenylmethane, N, N, N ', N'-tetramethyl-4,4'-diamino-diphenylmethane, 1, 2-di - [(2-methyl-phenyl) -amino] - ethane, 1,2-di (phenylamino) -propane, (o-tolyl) -biguanide, di- [4- (1 ', 3'-dimethylbutyl) -phenyl] amine, tert-octylated N-phenyl-naphthyl -amine, mixtures of mono- and dialkylated tert-butyl / tert-Octyldiphenylaminen, mixtures of mono- and dialkylated isopropyl / lsohexyl-diphenylamines, mixtures of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl 4H-1, 4-benzothiazine, phenothiazine, N-allylphenothiazine, N, N, N ', N'-tetraphenyl-1, 4-diaminobut-2-ene, N, N-bis- (2,2, 6,6-tetramethylpiperidin-4-yl-hexamethylenediamine, bis (2,2,6,6-tetra-methylpiperidin-4-yl) sebacate, 2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidine-4-ol.

Examples of other antioxidants are:

Aliphatic or aromatic phosphites, esters of thiodipropionic acid of thiodiacetic acid, or salts of dithiocarbamic or dithiophosphoric acid, 2,2,12,12-tetramethyl-5,9-dihydroxy-3,7,1-trithiazolidane and 2,2, 15,15-tetramethyl-5,12-dihydroxy-3,7,10,14-tetrathiahexadecane.

Metal deactivators

Examples of metal deactivators are: a) benzotriazoles and their derivatives, e.g. 2-mercaptobenzotriazole, .2,5-

Dimercaptobenztriazole, alkylbenzotriazoles (e.g., tolutriazole) and their derivatives, 4,5,6,7-tetrahydrobenzotriazole, 5,5'-methylenebisbenzotriazole; Mannich bases of

Benzotriazole or tolutriazole, e.g. 1- [di (2-ethylhexyl) aminomethyl) tolutriazole and 1- [di (2-ethylhexyl) aminomethyl) benzotriazole; Alkoxyalkylene triazoles such as 1- (nonyloxyrethyl) benzotriazole, 1- (1-butoxyethyl) -bentriazole and 1- (1-cyclohexyloxybutyi) tolutriazole, b) 1,2,4-triazoles and their derivatives, e.g. 3-alkyl (or aryl) -1,4,4-triazoles, Mannich

Bases of 1,2,4-triazoles such as 1- [di (2-ethylhexyl) aminomethyl-1,2,4-triazole; Alkoxyalkyl-1,2,4-triazoles, such as 1- (1-butoxyethyl-1,2,4-triazole; acylated 3-amino-1,2,4-triazoles, c) imidazole derivatives, eg 4,4'-methylene-bis ( 2-undecyl-5-methylimida cl, Bls [(t1 -rnethyl) - imidazol-2-] carbinolocty ^r lether d) sulfur-containing heterocyclic compounds, for example 2-mercaptobenzothiazole, 2,5-dimercapto-1, 3,4-thiadiazole. 2,5-dimercaptobenzthiadiaiol and its derivatives; 3,5-bis [di (2-ethylhexyl) amino-methyl / 7-yl-7,3-thiadiazolin-2-one. e) amino compounds, for example salicylidene-propylenediamine, salicylaminoguanidine and salts thereof

Examples of rust inhibitors are: a) organic acids, their esters, metal salts, amine salts and anhydrides, e.g. Alkyl- and Alkenyibernsteinsäuren and their partial esters with alcohols, diols or their hydroxycarboxylic acid amides of alkyl and A [kenylsuccinic acids, 4-nonylphenoxyacetic acid, alkoxy and Alkoxye thoxycarbonsäuren such as dodecyloxyacetic acid, dodecyloxy (ethoxy) -acetic acid and its amine salts, also N-oleoyl-sarcosine , Sorbitan mono-oleate, lead naphthenate,

A [kynylsuccinic anhydrides, e.g. Dodecenylsuccinic anhydride, 2- (2-carboxyethyl) -1-dodecyl-3-methylglycerol and its salts, in particular sodium and triethanolamine salts. b) Nitrogen-containing compounds, for example: primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic

Acids, e.g. oil-soluble alkyl ammonium carboxylates, further 1- [N, N-bis (2-hydroxyethyl) amino] -3- (4-nonylphenoxy) propan-2-ol. 1 1. Heterocyclic compounds, for example: Substituting imidazolines and oxazolines, 2-heptadeceny [-1- (2-hydroxyethyl) -imidazoline. c) Phosphorus-containing compounds, for example: amine salts of phosphoric acid partial esters or phosphonic acid partial esters, zinc dialkyldithiophosphates. d) Sulfur-containing compounds, for example: barium-dinonylnaphthalenesulfonates, calcium petroleum sulfonates, alkylthio-substituted aliphatic carboxylic acids, esters of aliphatic 2-sulfonic acids and their salts, e) glycerol derivatives; For example: glycerol monooleate, 1- (alkylphenoxy) -3- (2-hydroxyethyl) g [ycerines, 1-

(Afkylphenoxy) -3- (2,3-dihydroxypropyl) glycerols, 2-carboxyalkyl-1,3-dia [glycylcerols.

Dispersants Examples of dispersants are: polybutenylsuccinic amides or imides, polybutylphosphonic acid derivatives, basic magnesium, calcium and barium sulphonates and phenolates. Friction modifiers

Lubricants can contain various substances for the targeted modification of the friction properties. In the current state of the art, it is believed that typical oil-soluble friction reducing lubricant additives either adsorb to the metal surface of a frictional contact or form reaction layers. The former consist for example of long-chain carboxylic acids and their salts, esters, ethers, alcohols, amines, amides and imides. As an effect of such Reibverminderer an alignment of the polar groups and associated filming on the surface is assumed in frictional contact. By such a film, the contact of the solid is then prevented in case of failure of the actual oil film. However, the actual mechanism and influence of polar interactions such as dipole-dipole interactions or hydrogen bonds is not fully understood. Typical reaction layers forming Reibverminderer are, for example, saturated fatty acid esters, phosphoric and Triphosphorsäureester, xanthates or sulfur-containing fatty acids. This class also includes compounds which, under tribological stress in frictional contact, do not form solid but liquid reaction products with high carrying capacity. Examples of these are unsaturated fatty acids, partial esters of dicarboxylic acids, dialkylphthalic acid esters and sulforated olefin mixtures. In addition, organometallic compounds such as molybdenum dithiophosphonates and dicarbamates, organic copper compounds, as well as some solid lubricants such as graphite and M0S _{2 act} as Reibmindernde additives in lubricants. Additives for changing the friction properties in oil-lubricated start-up couplings are described, for example, in EP 0 622 444 A1.

The lubricant composition according to the invention is preferably suitable for use as a special lubricating fluid for active differentials with an acceleration stage and a double clutch, in particular in multi-disc clutches. The multi-plate clutch includes a plurality of friction and steel plates, which together with the lubricant composition of the invention form a tribological system to transmit the desired torque. The friction plate consists of a steel carrier and a corresponding friction material. As friction materials here are preferably sintered materials. The lubricant composition according to the invention is preferably used in a double clutch which includes friction fins made of scattered sintered materials. In contrast to common oil-lubricated multi-plate clutches such as start-up clutches in automatic transmissions, the clutches of the active differentials are operated exclusively in continuous slippage, whereby the lubricant is subject to extreme loads. As a result, in addition to a high thermal and mechanical load-bearing capacity, very specific requirements are made of the friction behavior with grit-containing sintering materials.

In the systems described, the lubricating fluids according to the invention ensure sufficiently high and stable coefficients of friction under continuous slip conditions and are distinguished, in particular, by high thermal stability and good efficiency properties in the active differentials.

Exemplary Embodiment For the preparation of the lubricant composition according to the invention, the following base oils and additives are used:

example

Lubricant Composition 1: A synthetic lubricant based on a hydrocracking oil Group III having the following composition was prepared:

Base oil: hydrocracked oil 99.57% by weight

Additives: zinc dithiophosphate 0.15% by weight

Magnesium sulphonate 0.28% by weight

Lubricant Composition 2: A synthetic lubricant based on a hydrocracking oil Group III having the following composition was prepared:

Base oil: hydro-cracking oil 95.4% by weight of additives: flow improver (methacrylate copolymer) 0.3% by weight

Zinc dithiophosphate 0.15% by weight

Magnesium sulfonate 0.28 wt.% And Antioxidant (diphenylamine) 0.1% wt.%

Foam inhibitor (silicone oil).

The above compositions have a zinc content of 1550 mg / kg, a phosphorus content of 3480 mg / kg, a magnesium content of 2800 mg / kg and a sulfur content of 2570 mg / kg.

The kinematic viscosity is 5.45 mm ² / s (centistokes) at 100 ⁰ C.

Claims

claims

A synthetic lubricant composition comprising at least 50% of a synthetic base oil and

- 0.03 to 5 wt.% Zinc dithiophosphate and

0.04 to 4% by weight of magnesium sulphonate, the composition having a zinc content of 1000 to 2000 mg / kg, a phosphorus content of 3000 to 4000 mg / kg, a magnesium content of 2000 to 3500 mg / kg and a sulfur content of 2000 to 4000 mg / kg.

2. Lubricant composition according to claim 1, characterized in that it

0.05 to 1% by weight of zinc dithiophosphate and

0.1 to 0.4% by weight of magnesium sulphonate.

3. Lubricant composition according to claim 1 or 2, characterized in that it consists of base oil and the additives zinc dithiophosphate and magnesium sulfonate.

4. A lubricant composition according to claim 1 or 2, characterized in that it further comprises 0-3 wt.% Flow improver and / or 0-5 wt.% Dispersant.

5. Lubricant composition according to one of claims 1 to 4, characterized in that the flow improver is selected from hydrogenated polystyrene co-isoprene (HSI), ethylene-propylene copolymers (OCP), polyisobutylene (PIB), polyalkyl acrylates and methacrylates ( PAMA), vinylpyrrolidone / methacrylate copolymers, polyvinylpyrrolidones, polybutene, olefin copolymers, styrene / acrylate copolymers, polyethers, alkylated naphthalene derivatives or mixtures thereof.

6. A lubricant composition according to any one of claims 1 to 5, characterized in that it has a kinematic viscosity of 3.0 to 18.0 mm ² / s (centistokes) at 100 ⁰ C, preferably 4.0 to 10.0 mm ² / s.

7. A lubricant composition according to any one of claims 1 to 6, characterized in that the base oil is a group III hydrocracking base oil or a group IV based PAO base oil.

8. Lubricant composition according to one of claims 1 to 7, characterized in that it comprises at least one further additive selected from antioxidants, detergents, high pressure abrasives (EP), friction modifiers (friction modifier), corrosion rust and foam inhibitors and / or Viscosity index improvers.

9. A lubricant composition according to any one of claims 1 to 8, characterized in that it contains 0.03 to 3 wt.% Calcium sulfonate, preferably 0.1 to 0.3 wt.%.

10. Use of a lubricant composition according to any one of claims 1 to 9 for lubricating a Getriebetribosystems.

1 1. Use according to claim 10, characterized in that the lubricant composition for lubricating an active differential with an acceleration stage and a dual clutch in the continuous slip operation is used.

12. A method for lubricating an active differential with an acceleration stage and a dual clutch, the friction lamellae from interspersed sintered materials, characterized in that a lubricant composition according to one of

Claims 1 to 9 used and added to the active differential.