KR20130096168A - Lubricant compositions for motor vehicle transmissions - Google Patents

Abstract

The invention relates to (a) organomolybdenum compounds, (b) one or more antiwear and extreme pressure additives selected from thia (di) azoles, (c) phosphites, phosphates Lubricant composition having 90 to 350 ppm molybdenum content, comprising at least one phosphorus-containing or phosphorus-sulfur-containing antiwear and extreme pressure additive selected from phosphonates, thiophosphates or thiophosphites; It is about. Used to lubricate gearboxes.

Description

Lubricant compositions for motor vehicle transmissions}

The present invention relates in particular to lubricant compositions, especially for automatic transmissions, for manual gear boxes.

Transmission components of automotive vehicles operate under high speeds and high loads. Thus, the oil for the transmission should act in particular to protect the parts against wear and fatigue, in particular to protect the gear teeth against flaking phenomena.

Flaking occurs after a long aging time, prior to visible light degradation. Mechanisms are not well known, but phenomena are initiated by the occurrence of cracks at a certain depth below the surface, and when the crack propagate and normal cracks occur on the surface, the flakes suddenly Are separated.

The prevention of this phenomenon is a reduction in friction while avoiding adhesion, which requires a reduction in contact stress due to the proper geometry of the part. Lubricants are involved in the prevention process, mainly by the physicochemical reactivity of the additives.

In general, sulfur, phosphorus, phosphor-sulfur or borate anti-wear and extreme pressure additives have transmissions that protect against flaking. It is added to give an oil. In addition, other additives present in the lubricant may have a positive or negative effect by propagation of cracks inside the component, depending on the flaking phenomenon.

Synchronizers present in manual gear boxes induce additional stress. Indeed, the components of the transmission comprise a cone and a ring device between the frictions that must be specifically controlled: the friction should be sufficient for the synchronization of the gears, otherwise synchronization Cones and rings should have the potential for dismantling because they block the device.

In addition, wear occurs in the cone-ring assembly if the friction level is not suitable for the geometry of the part.

The friction level is controlled by the addition of friction modifiers in the oil of the gear boxes.

Thus, in the oil of manual gear boxes, anti-wear and extreme pressure additives, friction modifiers, co-exist, which act on the surface of the part and provide both friction levels and flaking phenomena. Potentially affects everything.

Oil formulation of manual gear boxes allows easy replacement of gears, avoids blocking and wear of synchronous devices, has high protection against flaking, anti-wear and It is based on extreme pressure additives, selection of friction modifiers and specific dosage.

It is especially suitable for the anti-wear properties of oils such as organic molybdenum friction control compounds with organic phosphorus and / or organic sulfur and / or organic phosphor-sulfur wear and extreme pressure additives ( It is known how to formulate lubricant compositions comprising organic molybdenum friction modifier compounds.

US Pat. No. 6,806,241 discloses a sufficient amount of molybdenum source to obtain a composite containing any phosphorodithioate and thiadiazole compound, 1-12% by weight of molybdenum based on the weight of the complex. And a molybdenum complex prepared by the reaction of 1 to 2.5 moles of diethanolamine, which may be a fatty acid or glyceride of 1 to 2.5 moles of diethanolamine. For example, at a sulfur and phosphorus content of 90-350 ppm, it is not given in a configuration that includes molybdenum.

EP application 0874040 is based on the weight of organic sulfur compounds and complexes selected from phosphorodithioate, dithiocarbamates, bisdithiocarbamates, dimercaptothiadiazoles To an internal combustion engine comprising a molybdenum complex prepared by the reaction of a sufficient amount of molybdenum source and 1 to 2.5 moles of fat of 1 to 2.5 moles of diethanolamine to obtain a complex containing 1 to 12% by weight of molybdenum. Reveals lubricants for

Certain bonds of molybdenum composites with one or more of the mentioned organic sulfur compounds are also not given to the amount of Mo included in the lubricant composition. The example shows the amount of the composite of 0.5 to 1.5 mass% of the lubricant, which corresponds to the Mo content of the lubricant of 5 to 1800 ppm. Too strong or too low Mo content is not suitable for formulating lubricants in gearboxes. Indeed, flaking or blocking problems of the synchronization device may occur. It is likewise applied to the selection and quantification of phosphor-sulfur additives and / or sulfur.

Application WO 2005035700 discloses an organic molybdenum compound selected from anti-wear compounds and dithiocarbamate, which may be molybdenum dithiophosphates or dithiocarbamate and dimercaptothiadiazole. A lubricant composition is disclosed. This application does not disclose the combination of specific molybdenum content using extreme pressure agents and abrasion resistant thiazoles.

In addition, the use of molybdenum in the form of dithiophosphate or dithiocarbamate creates additional problems of abrasion and / or blocking of the synchronizer, and may be possible to peel off.

However, the compositions of the prior art do not have sufficient presence of sulfur and phosphorus and specific quantification of urea Mo, which impedes the blocking of the synchronizing device in a satisfactory manner and permits them to have properties to protect against wear and peeling of the synchronizing device. . Such compositions are therefore not suitable as lubricants for gearboxes of motor vehicles, in particular manual gearboxes.

Borate oil in oils known for manual gearboxes has a good compromise between the other properties described above. These oils can appear without any sulfur, phosphorus, or phosphorus-sulfur compounds, and to date, sulfur, phosphorus or phosphorus-sulfur additives The technique based on) does not give the possibility of achieving the level of performance achieved with borate with respect to protection against wear and tear of the synchronizer.

Despite their many advantages and good extreme pressure performance, the use of borate salts is undesirable because there is a risk of contamination of the lubricant with water. Indeed, the inorganic borate is partially water soluble, the amount of water present in the molecule increases and has the effect of altering the structure of the borate. The structure of the borate can be modified by the substantial amount of water present in the medium, and the structure of the borate can crystallize and have a knife-like crystalline form with a size greater than 100 nm. In this case, the borate may block the crystallization system in the gearbox.

The use of borate oils thus requires a unique design of a waterproof system and a manual gearbox, and preferably has the cost and complexity to be avoided.

This protects the gearboxes of automobiles, especially the gear teeth, which do not react to water and allow easy change of gears, avoid interruptions and limit the wear of the synchronous device. There is a need for oil for imparting manual gearboxes.

The object of the present invention is to provide sulfur-containing extreme pressure additives and phosphor-sulfur extreme pressure additives or phosphorus-sulfur-containing extreme pressure additives for use in the lubrication of automobile vehicles, in particular gear boxes. It is a lubricant composition comprising a molybdenum complex of the ester-amide type combined with a phosphor-sulfur extreme pressure additive. Particularly relevant use relates to the manual gearbox of an automobile vehicle.

SUMMARY OF THE INVENTION

(a) organic molybdenum compound

(b) one or more anti-wear and extreme pressure additives selected from thia (di) azoles;

(c) one or more phosphorus-containing and / or phosphorus-sulfur wear and extreme pressure additives selected from phosphite, phosphate, phosphonate, thiophosphates or thiophosphite ; It is a lubricant composition comprising a.

The lubricant composition has a molybdenum content of 90-350 ppm.

Preferentially, the lubricant composition according to the invention has a molybdenum content of 100 to 200 ppm, preferentially 140 to 180 ppm.

The lubricant composition according to the invention preferentially has a phosphorus content of 500-700 ppm, even more preferentially 520-650 ppm.

According to an embodiment, the lubricant composition according to the invention is a compound (c) comprising at least one thiophosphate, preferentially at least one dithiophosphate, preferentially at least one amine dithiophosphate dithiophosphate).

According to an embodiment, the lubricant composition according to the invention comprises at least one thiadiazole, preferentially at least one dimercaptothiadiazole as compound (b).

The lubricant composition according to the present invention comprises 0.35 to 1% by mass of thiazole, preferentially 0.35 to 1% by mass of dimercaptothiadiazole.

According to an embodiment, the lubricant composition according to the invention comprises as compound (a) an organic complex of at least one molybdenum obtained by the reaction:

(i) fats in the form of mono-, di- or tri-glycerides or fatty acids

(ii) amine source of formula (I)

(I)

(I)

Wherein X ¹ and X ² is O or N, and otherwise, or X ¹ when X ² is O and n and m = ^1, X 1 and n or m = 2 when X ² is N, O.

(iii) a molybdenum source selected from molybdenum trioxide or molybdates, preferentially ammonium molybdate, in an amount sufficient to provide 0.1-20.0% molybdenum based on the weight of the composite;

Preferred compound (ii) is diethanolamine or 2- (2-aminoethyl) aminoethanol (2- (2-aminoethyl) aminoethanol).

Preferentially, fat (i) is tri-glyceride or mono-, di- or fatty acid of fatty acids containing 4 to 28 carbon atoms, preferentially 8 to 18 carbon atoms, or 4 to Fatty acids containing 28 carbon atoms, preferentially 8-18 carbon atoms.

According to an embodiment, the molybdenum complex (a) comprises at least one or more of the following compounds, singly or in mixtures:

(II)

(II)

(III)

(III)

X ¹ and X ² are O or else N, and

When X ¹ is O, n = 1 and when X ² is O, m = 1

When X ¹ is N, n = 2 and when X ² is N, m = 2

R ₁ and R ₂ are lipid hydrocarbon chains containing 3 to 27 carbon atoms, preferentially 7 to 17 carbon atoms.

According to a further embodiment, the molybdenum complex (a) comprises at least one compound corresponding to the formula:

(IV)

(IV)

R ₁ is lipid hydrocarbon chains of 3 to 27 carbon atoms, preferentially 7 to 27 carbon atoms.

According to another embodiment, the molybdenum complex (a) comprises at least one compound corresponding to the formula:

(V)

(V)

R ₁ is lipid hydrocarbon chains of 3 to 27 carbon atoms, preferentially 7 to 27 carbon atoms.

The invention also relates to the use of the compositions described above for the lubrication of motor vehicles, in particular of gearboxes.

According to an embodiment, the present invention relates to the use of the composition described above for the lubrication of a manual gearbox, in particular a manual gearbox of an automatic vehicle.

Organic Molybdenum Compounds:

According to the invention, the lubricant composition may comprise fat-soluble organic molybdenum compounds, in particular molybdenum dithiophosphates and dty, such as molybdenum carboxylates, esters, amides It is not a way of limiting the various organic complexes of dithiocarbamates and molybdenum and include fatty acid derivatives (esters, amines, amides) or glycerides or fatty acids, fats. Obtained by the reaction of molybdenum oxide or ammonium molybdates.

The lubricant composition according to the invention preferentially comprises a complex of sulfur-free and unmanned molybdenum having amide-type ligands prepared primarily by the reaction of a molybdenum source, such as fatty acids contained in vegetable or animal oils, Examples include fatty acid derivatives and amines, molybdenum trioxides containing 4 to 28 carbon atoms, preferentially 8 to 18 carbon atoms.

For example, the synthesis of such compounds is described in patents US 4,889,647, EP0546357, US 5,412,130, EP 1770153.

Organic complexes of the present molybdenum can be obtained by reaction:

(i) fats in the form of mono-, di- or tri-glycerides or fatty acids

(ii) amine source of formula (I)

(I)

(I)

Wherein X ¹ and X ² are O or else N and n and m = 1 when X ¹ or X ² is 0 and n and m = 2 when X ¹ or X ² is N.

(iii) a molybdenum source selected from molybdenum trioxide or molybdates, preferentially ammonium molybdate, in an amount sufficient to provide 0.1-20.0% molybdenum based on the weight of the composite;

They generally comprise 7-8.5% by weight of molybdenum based on the weight of the composite.

In a particular embodiment, the organic molybdenum compounds of the composition according to the invention comprise at least one of the following compounds, either singly or in admixture.

(II)

(II)

(III)

(III)

X ¹ and X ² are O or else N, and

When X ¹ is O, n = 1 and when X ² is O, m = 1

When X ¹ is N, n = 2 and when X ² is N, m = 2

R ₁ and R ₂ are lipid hydrocarbon chains containing 3 to 27 carbon atoms, preferentially 7 to 17 carbon atoms.

According to an embodiment, the molybdenum compounds of the composition according to the invention are prepared by the reaction:

(i) fatty acids in the form of mono-, di- or tri-glycerides or fatty acids;

(ii) diethanolamine or 2- (2-aminoethyl) aminoethanol (2- (2-aminoethyl) aminoethanol)

(iii) a molybdenum source selected from molybdenum trioxide or molybdates, preferentially ammonium molybdate, in an amount sufficient to provide 0.1-20.0% molybdenum based on the weight of the composite;

In a particular embodiment, the organic molybdenum compounds of the composition according to the invention comprise one or more of the following compounds in single or mixture of (IV) or (V).

(IV)

(IV)

(V)

(V)

R ₁ is lipid hydrocarbon chains of 3 to 27 carbon atoms, preferentially 7 to 27 carbon atoms.

The content of the organic molybdenum compound in the composition according to the invention is adjusted for the molybdenum content of the composition of 90-350 ppm, preferentially 100-200 ppm, even more preferentially 140-180 ppm.

Too little molybdenum content creates a problem of blocking the synchronizer and potential wear of the cone-ring assembly of the synchronizer.

On the other hand, too strong molybdenum content adversely results in flaking.

Thia (di) azoles:

Thia (di) azoles are compounds that contain both sulfur and nitrogen atoms in a five-membered ring. Benzothiazoles are a specific type of Thia (di) azoles. The term thiadiazoles are cyclic compounds containing sulfur and nitrogen atoms per five atom rings, as well as thiadiazoles containing sulfur and two nitrogen atoms in such rings. ).

Such compounds may or may not be substituted with hydrocarbon compounds that increase solubility in oils.

According to an embodiment, thia (di) azoles of the lubricant composition according to the invention are not substituted with benzothiazoles, thiazoles, thiadiazoles.

In an embodiment, the thia (di) azole of the composition according to the invention is for example 2,5-dimercapto-1,3,4-thiadiazole (2,5-dimercapto-1,3,4-thiadiazole ), 3,5-dimercapto-1,2,4-thiadiazole (3,5-dimercapto-1,2,4-thiadiazole), 3,4-dimercapto-1,2,4-thia Diazole (3,4-dimercapto-1,2,4-thiadiazole), 4,5-dimercapto-1,2,3-thiadiazole (4,5-dimercapto-1,2,3-thiadiazole) , Dimercaptothiadiazoles which are 3-methylmercapto- (3-methylmercapto-) and 5-mercapto-1,2,4-thiadiazole )to be.

All compounds are used singly or in mixtures.

In general, thia (di) azole is represented by 0.35 to 1% by mass of the compound according to the present invention.

Preferentially, the composition according to the invention contains 0.35 to 1%, preferentially 0.34 to 0.45% by mass of dimercaptothiadiazole.

Phosphorus containing or phosphorus-sulfur containing compounds:

Phosphorus-containing compounds of the lubricant composition according to the invention are extreme pressure additives and anti-wear, such as phosphates, phosphites or phosphonates. Such conditions include, for example, phosphoric, such as alkyl phosphates, alkyl phosphonates, alkyl phosphonates and their salts such as, for example, amine salts. phosphoric, phosphorous, phosphonic acids, their mono-, di- and tri-esters.

Phosphorus-sulfur anti-wear and extreme pressure additives used in the present invention include (mono- or di-) extreme pressure additives and thiophosphites. Such conditions include thiophosphoric and thiophosphorous acids, esters of such acids, their salts, dithiophosphites and dithiophosphates.

In an embodiment, the phosphorus-sulfur abrasion and extreme pressure additives of the composition according to the invention are thiophosphates corresponding to formula (VI).

(VI)

(VI)

X ₃ and X ₄ are each independently S or O, at least one of S, R ₃ and R ₄ are hydrogen or an alkyl group having 1 to 22 carbon atoms, M Is a metal element of groups IIA, III, VA, VIA, IB, VIB, VIII of the Periodic Table, and another M is the primary of formula (R5) (R6) (R7) N Ammonium made of secondary or tertiary amines, wherein R5, R6, R7 is hydrogen or an alkyl group containing 1-18 carbon atoms Then n = 1.

More specific compounds are preferentially dithiophosphates (X ₃ and X ₄ sulfur) of zinc or amines. Amine dithiophosphates are more specific compounds.

Examples of phosphor-sulfur anti-wear and extreme pressure additives include monobutylthiophosphate, monooctylthiophosphate, monolaurylthiophosphate ), Dibutylthiophosphate, dilaurylthiophosphate, tributylthiophosphate, tributylthiophosphate, trioctylthiophosphate, triphenylthiophosphate, trilaurylthiophosphate, trilaurylthiophosphate ), Monobutylthiophosphite, monooctylthiophosphite, monoooctylthiophosphite, monolaurylthiophosphite, dibutylthiophosphite, dibutylthiophosphite, dilaurylthiophosphite, tributyl Tributylthiophosphite, triox Thio phosphite (trioctylthiophosphite), triphenyl phosphite thio (triphenylthiophosphite), there may be mentioned lauryl tree thio phosphite (trilaurylthiophosphite) and its salts.

Examples of esters of thiophosphoric acid and thiophosphorous acid react with ammonia or amines, or nitrogen containing compounds such as zinc oxide or zinc chloride. It is obtained by.

Preferentially, the amount of the additive is adjusted according to the invention so that the phosphorus content of the oil comprises 500 to 700 ppm, preferentially 520 to 650 ppm.

Too little content of anti-wear and extreme pressure elements leads to peeling problems.

In addition, too strong content of anti-wear and extreme pressure elements (including organic molybdenum compounds as well as friction modifiers) can adversely affect the change of gears: cone ring friction coefficient can be very small and prevents gear synchronization and thus gear change.

In addition, it is desirable to limit the sulfur and phosphorus content for environmental reasons in the required lubricant composition.

The effective compromise between these three properties depends on the specific quantification of friction modifiers, anti-wear and extreme pressure compounds and thus the Mo, S and P elements in these compounds.

Bases:

Compositions in the present invention may comprise certain types of synthetic or natural lubricant bases, animals or plants suitable for use.

The base oil (s) used in the compositions according to the invention are groups I to V in the part defined in API classification (API classification, or equivalent to them according to API classification) as a single or mixture summarized below. It may be oil of mineral or synthetic origin.

In the present invention, the mineral base oil is a solvent such as solvent, hydrotreatment, hydrocracking and hydroisomerization, hydrofinishing, and deasphalting. And all types of bases obtained by atmospheric and vacuum distillation of crude oil, followed by refining processes such as deparaffining.

In addition, the base oil of the composition according to the present invention may be a synthetic oil such as polyalphaolefins, polyalphaolefins or alcohols and specific esters of carboxylic acids used as the base oil. For example, it is obtained from a monomer having a viscosity of 100 ° C. composed of 1.5 to 15 cSt and 4 to 32 carbon atoms (for example, octane and decene). In general, their weight molecular mass is comprised between 250 and 3000. Mixtures of synthetic or mineral oils can be used.

In the present invention, when they do not have properties, in particular viscosity, viscosity index, sulfur content, resistance to oxidation... There is no restriction on the use of such lubricant bases for the production of compositions suitable for the use of gearboxes, in particular motor vehicles, in particular manual gearboxes.

Preferentially, the lubricant base represents at least 50%, preferentially at least 60%, at least 70% by mass of the lubricant composition according to the invention. Generally, the lubricant base is represented by 75-90 mass% of the composition of the present invention.

Preferentially, the lubricant composition of the present invention comprises a synthetic base of group IV or a mineral base of group I and / or III according to the API classification.

Other additives:

Lubricant compositions of the present invention may also contain, for example, amines such as phenols or diphenylamines substituted with at least one of their ortho positios, such as alkyl groups, detergents, for example sulfonates. Or certain types of additives suitable for using phenolic antioxidants.

Agents primarily for increasing the viscosity index are gearboxes, in particular automatic gearboxes, preferentially for example polymethacrylates (PMA), polyisobutenes (PIB) or fatty acid esters. It is present in amounts of 5-25% by mass to give suitable viscosimetric properties for use in manual gearboxes.

Yes:

The weight compositions and performances for synchro wear, synchro blocking, exfoliation of the prepared lubricant composition are shown in Table 1 below.

Peel testing is performed under the following conditions:

BCFP Sermes Bench

Renault JR5-125 gearbox, pair of differentials 14x63, secondary shaft 8200280045 and ring 8200280134, three pairs of primary shafts 8200107846 28x37 and idler pinion idler pinion) 3 ° 7700114048

2.3 liters of oil, 110 ° C oil temperature

Input torque: 148mN

1st speed 3000rpm

Duration: 142 hours 3 levels

Every 142 hours, the first axis of change of the idler pinion 3 ° and the roller bearings.

Peeled surface evaluation:

Final score of pinion / differential ring pair after 426 hours,

Score of 3 pairs 28x37 1st Axle / idler pinion 3 ° after 142 hours

Depending on the score results of these parts, it is referred to as pass (satisfactory score) or failure (too large peeled surface).

The checks for synchronizing the devices are performed on cone-ring pairs under the following conditions (SYNC-40 procedure):

For example, a 54 mm threaded brass ring with reference 7700 708 152 or 7700 869 430

Cone of idler pinion gear box JXX, stone rectified carbonitride steel,

For example, reference 7700 867 612 or 7700 740 880

Oil: oil level in the middle of 250ml oil, ring or pinion

SAE2 / A machine SAE / 2 synchro adapter

I = 0.155 m 2 / kg

N = 300 rpm

F = 60 daN

T = 6s (continuous time between two continuous braking operations)

n = 10,125 gear change interval (21 hours)

If the synchronous cutoff test passes by the number of cycles during the 10125 gear change cycle, the separation between the cone and the ring requires the application of a counter-torque of 2mN or more, at most 100 cycles.

Synchronizer wear checks are performed on cone-ring pairs under the following conditions (Sequence SYNC-13, SAE 2-A):

For example, a 54 mm threaded brass ring with reference 7700 708 152 or 7700 869 430

Cones of idler pinion gear box JXX, stone rectified carbonitride steel,

For example, reference 7700 867 612 or 7700 740 880

Huile: 125 ml of oil, oil level at the bottom of the ring

SAE2 / A machine SAE / 2 synchro adapter

I = 0.155 m 2 / kg

N = 600 rpm

F = 60 daN

T = 3,5 s (continuous time between two continuous braking operations)

n = 20,000 gear change intervals (20 hours)

At the end of 20,000 cycles: Axial wear of the synchronizer ring / gear cone pair is measured in mm. In order to be allowed (passed), it must be approximately 0.30 mm. Abrasion of 1 mm or more is disqualified.

debate:

Oils A and B are oils according to the invention: Oils C and D are water sensitive borate oils.

Oils A and B have a performance level on the wear of the synchronous device corresponding to borate oils and pass the inspection of peeling and blocking in the same way.

Oil E includes antiwear and extreme pressure additives such as oil A and also phosphorus containing compounds of the phosphite / phosphate type; Oil E does not contain any friction modifiers with molybdenum. Wear of the synchronizer is an unacceptable level (0.84 mm).

Oils F, G and H are oils of the invention and include various friction modifiers with the same additives in sulfur containing and phosphorus-sulfur wear and extreme pressure agents but without molybdenum. Wear of the synchronous device is very important like this oil.

Oils I and L, as oils of the present invention, include friction modifiers having the same additives as for sulfur-containing and sulfur-phosphorus abrasion and extreme pressure agents and having molybdenum of ester amide time.

The ester Mo content of oil I was 400 ppm and oil I failed with respect to exfoliation.

The mass Mo content of oil L is 80 ppm, and oil L failed with regard to synchronous cutoff.

Oil J has the same additives as sulfur containing and phosphorus-sulfur abrasion and extreme pressure agents, but does not contain any molybdenum. Fatty acid mono esters exist as friction modifiers. Oil J failed on synchronous shutoff.

Oil K has the same additives of sulfur containing and phosphorus-sulfur abrasion and extreme pressure additives as oils of the invention and do not contain any molybdenum. Oil K does not contain any friction modifiers. The oil failed with regard to synchronous shutoff.

Oils M and N are sulfur containing compounds and do not contain any thiazoles. Oil M is also free of molybdenum. Such oils have particularly tragic consequences on exfoliation. It should be noted that this oil does not contain any dimercaptothiadiazole.

Mo complex: organic molybdenum complex with amide ligand

Claims (14)

As a lubricant composition,
(a) an organic molybdenum compound,
(b) one or more wear and extreme pressure additives selected from thia (di) azoles,
(c) one or more phosphorus-containing and / or phosphorus-sulfur wear and extreme pressure additives selected from phosphites, phosphates, phosphonates, thiophosphates or thiophosphites ;;
A lubricant composition, wherein the lubricant composition has a molybdenum content of 90 to 180 ppm. The method of claim 1,
A lubricant composition having a molybdenum content of 100 to 200 ppm and preferentially 140 to 180 ppm. 3. The method according to any one of claims 1 to 2,
A lubricant composition having a phosphorus content of 500 to 700 ppm and preferentially 520 to 650 ppm. 4. The method according to any one of claims 1 to 3,
A lubricant composition comprising (c) at least one dithiophosphate, preferentially at least one amine dithiophosphate. The method according to any one of claims 1 to 4,
A lubricant composition comprising as compound (b) at least one thiadiazole, preferentially at least one dimercaptothiadiazole. The method according to claim 1, wherein
A lubricant composition comprising 0.35 to 1% by mass of thiadiazole, preferentially 0.35 to 1% by mass of dimercaptothiadiazole ((dimercaptothiadiazole)). 7. The method according to any one of claims 1 to 6,
As compound (a),
(i) fats in the form of mono-, di- or tri-glycerides or fatty acids
(ii) amine source of formula (I):

(I)
X ¹ and X ² are O or N, n and m = 1 when X ¹ or X ² is O, n and m = 2 when X ¹ or X ² is N,
(iii) molybdenum selected from molybdenum trioxide or molybdates, preferentially ammonium molybdate, in an amount sufficient to provide 0.1-20.0% molybdenum based on the weight of the complex sauce; A lubricant composition comprising an organic composite of at least one molybdenum obtained by the reaction of. 8. The method of claim 7,
The compound (ii) is diethanolamine or 2- (2-aminoethyl) aminoethanol (2- (2-aminoethyl) aminoethanol). The method according to any one of claims 7 to 8,
The mono-, di- or tri- glycerides of fatty acids in which the fat (i) comprises 4 to 28 carbon atoms, preferentially 8 to 18 carbon atoms Or a fatty acid comprising 4 to 28 carbon atoms, preferentially 8 to 18 carbon atoms. 10. The method according to any one of claims 7 to 9,
Wherein said molybdenum complex (a) is a single or a mixture and contains at least one of the following compounds,

(II)

(III)
X ¹ and X ² are O or N, and
When X ¹ is O, n = 1 and X ² is O, m = 1,
When X ¹ is N, n = 2 and when X ² is N, m = 2,
Wherein R ₁ and R ₂ is a lipid hydrocarbon chain (fatty hydrocarbon chains) containing 3 to 27 carbon atoms, preferentially 7 to 17 carbon atoms. 10. The method according to any one of claims 7 to 9,
The molybdenum complex (a) comprises at least one compound corresponding to the following formula,

(IV)
Wherein R ₁ is a lipid hydrocarbon chain comprising 3 to 27 carbon atoms, preferentially 7 to 27 carbon atoms. 10. The method according to any one of claims 7 to 9,
The molybdenum complex (a) comprises at least one compound corresponding to the following formula,

R ₁ is a lipid hydrocarbon chain containing 3 to 27 carbon atoms, preferentially 7 to 27 carbon atoms,
Use of a composition according to any of the preceding claims for lubricating a gear box, in particular a gear box of an automatic vehicle. The method of claim 13,
The use of the composition wherein the gear box is a manual gear box.