WO1994014933A1

WO1994014933A1 - Final-drive lubricating oil composition

Info

Publication number: WO1994014933A1
Application number: PCT/JP1993/001919
Authority: WO
Inventors: Noboru Tajima; Koji Takemitsu; Naoto Ohtsuka; Masaaki Shiomi
Original assignee: Tonen Corporation
Priority date: 1992-12-29
Filing date: 1993-12-28
Publication date: 1994-07-07
Also published as: EP0677571A1; CA2151582A1; AU5717294A; EP0677571A4; JPH06200270A

Abstract

A final-drive lubricating oil composition comprising a base oil and, added thereto, (A) 1-10 wt.% of a sulfurized oxymolybdenum organophosphorodithioate represented by general formula (1), (wherein R?1 and R2¿, which may be the same or different from each other, represent each C¿4?-C18 alkyl or alkenyl; and p and q represent each a positive integer provided the sum of them equals 4), (B) 3-15 wt.% of at least one sulfur-base extreme-pressure agent selected from among sulfurized olefins and alkyl sulfides and (C) 0.1-5 wt.% of at least one phosphorus-base extreme-pressure agent selected from among phosphoric esters, phosphorous esters and alkyl-amine salts of phosphoric esters, each based on the whole composition. The composition serves to further improve the transmission efficiency at the differential gear under varied conditions of input torque, input rotational speed and oil temperature as compared with the conventional compositions containing additives based on sulfur and phosphorus compounds, thus leading to fuel consumption improvement.

Description

Specification

Lubricating oil composition for final reduction gear

Field of the invention

The present invention provides a novel lubricating oil composition for final reduction gears, more specifically, compared to a conventional composition containing an SP additive, under various conditions such as input torque, input rotation speed, and oil temperature. definitive further improved transmission efficiency in the differential gear, and relates to a lubricating oil composition for a final reduction gear for automotive use, such as the front Enjin rear wheel drive ^gamma 'Mel o

Conventional technology

The final reduction gear (final drive) of a car has (1) a function to further reduce the power decelerated by the transmission and change the force and direction to a right angle, and (2) a function to shift the right and left when the vehicle turns. It has a differential function to ensure smooth operation even if a rotational differential force occurs in the drive wheels.The former function is performed by the reduction gear, and the latter is performed by the differential device. . The reduction gear is composed of a reduction gear and a reduction gear, and a high void gear is generally used as the reduction gear.

On the other hand, a differential device consists of two or four differential small gears built into a differential gear box and two differential large gears corresponding to them. The differential pinion is connected to the differential gear box by a shaft so that it can revolve around the shaft and revolve with the gear box, so that the vehicle turns and the differential rotation of the inner and outer wheels is reduced. , The difference in rotation can be absorbed mechanically.

Since the high void gear of the gear transmission mechanism used in such a final reduction gear of an automobile is exposed to severe conditions such as high-speed rotation and high load, a gear oil having excellent anti-seizure and anti-wear properties is required. For this reason, sulfur extreme pressure agents such as sulfur sulfide and alkyl sulfide are generally used to improve anti-seizure properties, and phosphoric esters, phosphites, and phosphoric esters are used to improve anti-wear properties. A phosphorus-based extreme pressure agent such as an alkylamine salt is added to a base oil.

However, with such conventional SP additives, the extreme pressure agent and the gear oil provided with anti-wear properties, the transmission efficiency of the differential gear is limited by the input torque and the input rotation speed. 90% to 95% depending on conditions such as oil temperature, etc. This is not entirely satisfactory. Therefore, it is desired to develop a lubricating oil composition for final reduction gears that further improves the transmission efficiency of the differential gear under various conditions such as input torque, input rotation speed, and oil temperature, and improves fuel efficiency. I was Disclosure of the invention

Under such circumstances, the present invention provides a differential gear transmission under various conditions such as input torque, input rotation speed, oil temperature, and the like, in comparison with a conventional compound containing an SP additive. The purpose of the present invention is to provide a lubricating oil composition for a final reduction gear used in an automobile such as a front engine and a rear wheel drive system, which has further improved efficiency and improved fuel efficiency. .

Means for solving the problem

The present inventors have conducted intensive studies to develop a lubricating oil composition for a final reduction gear having the above-mentioned preferable properties. As a result, the lubricating oil base oil was compared with oxymolybdenum sulfide organophosphorodithioate. The present inventors have found that a lubricating oil composition containing a sulfur-based extreme pressure agent and a phosphorus-based extreme pressure agent at predetermined ratios can achieve the object, and based on this finding, the present invention is based on this finding. It was completed.

That is, the present invention relates to (A) a general formula [1]

MO ₂ S p O _q …… [1]

(In the formula, R ′ and R ² each represent an alkyl group or an alkenyl group having 4 to 18 carbon atoms, which may be the same or different, and p and q each represent a sum of 4 Is a positive integer such that

1 to 10% by weight of oxymolybdenum sulfide organophosphorodithioate represented by the formula: and (B) at least one sulfur-based extreme pressure agent selected from among olefin sulfides and alkyl sulfides 3 to 15% by weight And (C) at least one phosphorus-based electrode selected from phosphate esters, phosphite esters and alkylamine salts of phosphate esters. The present invention provides a lubricating oil composition for a final reduction gear characterized by containing 0.1 to 5% by weight of a pressure agent.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic view of the apparatus used in the LFW-1 friction test.

FIG. 2 is a graph showing the relationship between the input torque and the transmission efficiency in the lubricating oil of the present invention and the SP-based compounded oil.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The base oil used in the lubricating oil composition of the present invention is not particularly limited, and those conventionally used as base oils for lubricating oils, for example, mineral oils and synthetic oils are used. Mineral oils include, for example, 60 neutral oils, 100 neutral oils, 150 neutral oils, 300 neutral oils, 500 neutral oils by solvent refining or hydrorefining, and wax components from these base oils. A low pour point base oil whose low-temperature fluidity has been improved by removal thereof may be mentioned. These may be used alone or in a combination of two or more at an appropriate ratio.

On the other hand, synthetic oils include, for example, poly-α-olefins, diesters, polyesters, and polyglycol esters. These base oils are usually used alone, but are mixed with the mineral oil. Can be used. The mixing ratio of the synthetic oil and the mineral oil is, for example, a weight ratio of 80:20 to 20:80.

The base oil used in the composition of the present invention preferably has a viscosity at 100 ° C. of 3 to 20 cSt.

In the lubricating oil composition of the present invention, as the component (A), a compound represented by the general formula (1):

M 0 ₂ S _P O _q …… [1]

The oxymolybdenum sulfide organophosphorodithioate (Mo DTP) represented by the following formula is used. In the general formula (1), R ¹ and R ² are each an alkyl group or an alkenyl group having 4 to 18 carbon atoms, which may be the same or different, and may be linear or branched. It may be either chain-like or cyclic. p and q are positive integers such that their sum is 4. Examples of R ¹ and R ² include a butyl, pentyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, lauryl, myristyl, nonoremicyl, stearyl, butenyl, pentenyl, octenyl, orylyl group And the like.

In the general formula (1), specific examples of Mo DTP in which R ′ = R ² and p = q = 2 include oxymolybdenum dibutyl phosphorodithioate, oxymolybdenum dipentyl phosphorodithioate, and sulfide Oxymolybdenum dihexyl phosphorodithioate, oxymolybdenum dioctyl phosphorodithioate, oxymolybdenum sulfide-di 2 -ethylhexyl phosphorodithioate, oxymolybdenum didecyl phosphorodithioate, sulfide Oxymolybdenum dilauryl phosphorodithioate, oxymolybdenum distearyl phosphorodithioate, oxymolybdenum dibutenyl phosphorodithioate, oxymolybdenum dipentenyl phosphorodithioate, oxymolybdenum dipentenyl phosphorodithioate, oxymolybdenum sulfide Di-1 2 —ethylhexenylho Horojichioeto, sulfurized O carboxymethyl molybdenum O rail phosphonium port Jichioeto, such as cyclohexyl phosphorodithioate di Chio benzoate and the like to sulfurization O carboxymethyl molybdenum di cycloalkyl.

One of these Mo DTPs may be used alone, or two or more thereof may be used in combination. The compounding amount is 1 to 10% by weight, preferably 1 to 7% by weight based on the total weight of the composition. %. If this amount is less than 1% by weight, the effect of improving the transmission efficiency of the differential gear under each condition such as input torque, input rotation speed, oil temperature, etc. will not be sufficiently exerted, and if it exceeds 10% by weight, the amount will increase. However, no improvement in the effect is observed, and sludge is likely to be caused.

In the lubricating oil composition of the present invention, as the component (B), at least one sulfur-based extreme pressure agent selected from the group consisting of an olefin sulfide and an alkyl sulfide is used. As the sulfided olefin, for example, the general formula (2)

R ^{: t} -S _x -R ⁴ …… [2] And the like. In the general formula (2), R ^{: 1} is an alkenyl group having 4 to 12 carbon atoms, IT is an alkyl group or an alkenyl group having 4 to 12 carbon atoms, and ^Ra and R ⁴ are linear or branched. And X may be an integer of 1 to 8. A typical example of such an sulfide is diisobutylene sulfide (x = l).

On the other hand, as the alkyl sulfide, for example, the general formula [3]

R ^r, -S _y -R ⁽ⁱ …… [3]

And the like. In formula (3), R ⁵ and R ^u are each an alkyl group having 4 to 12 carbon atoms, which may be the different from one from each other identical, also linear, branched, Y may be an integer of 1 to 8; Representative examples of such alkyl sulfides include di-t_butyl disulfide and di-t-butyl trisulfide. In the composition of the present invention, the sulfur-based extreme pressure agent of the component (B) may be used singly or in combination of two or more. The compounding amount is based on the total weight of the composition. It is selected in the range of 3 to 15% by weight, preferably 5 to 10% by weight. The sulfur-based extreme pressure agent generally has a function of forming a sulfide film on the friction surface and improving the load-bearing performance of the base oil. If the compounding amount is less than 3% by weight, these functions and effects are not sufficiently exhibited, and the oil is unsuitable as a gear oil for automobiles. If the amount exceeds 15% by weight, no improvement is observed for the amount. It is also difficult to dissolve in base oil.

In the lubricating oil composition of the present invention, as the component (C), at least one phosphorus extreme pressure agent selected from phosphate esters, phosphorous esters and alkylamine salts of phosphate esters is used.

The phosphate ester (Pa) and the phosphite ester (P i) are, for example, 0 = P (OR ⁷ ) (OR ⁸ ) (OR ⁹ ), 0 = P (OH) (OR ⁷ ) (OR ⁸ )ヽ 0 = P (0H) ₂ (OR ¹ ), P (OR ¹ ) (OR ⁸ ) (OR ⁹ ), P (OH) (OR ⁷ ) (OR ⁸ ), P (0H) ₂ (OR ⁷ )

Various phosphorus compounds represented by R ⁷ , R ^8, and R ^{9 in} each of the above formulas each have a linear, branched, or cyclic alkyl or alkenyl group having 4 to 30 carbon atoms, and preferably 20 or less, or an aryl group. Or alkyl aryl And they may be the same or different.

Typical examples among these phosphate esters and phosphite esters, a mixture of _{(C, RH 3S O) P} (0H) 2 0 and _{_{(C 18 H 35 0) 2P}} (OH) 0 there O Reiruashi' Dohosufuwe Ichito, and _{_{(C L () H: 0}} ) Jiore Iruhai mud Gen phosphine eye Bok and the like represented by the ₂ P (0H).

On the other hand, an alkylamine salt of a phosphate ester (P a-A) is a reaction product of a phosphate ester and an alkylamine, such as those represented by the general formula [4]

0

II

_{(R'.0) M P_ (OH)} 3 - M - (NH "R":, - n) 3 - , such as _m ...... [4] In those represented may be mentioned.

In the general formula (4), R ′ ° is a linear, branched, or cyclic alkyl or alkenyl group, aryl group or alkyl aryl having 4 to 30 carbon atoms, preferably 20 or less. R ¹¹ is a linear, branched, or cyclic alkyl or alkenyl group having 4 to 30 carbon atoms, preferably 20 or less, m and n are each 1 or 2; R ^{1 Q} may be the same or different, and a plurality of R ^M may be the same as or different from each other.

In the above general formula [4], R "represents, for example, butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, lauryl, myristyl, no. Lumityl, stearyl, oleyl, eicosyl, phenyl, A cresyl group; R ¹ ′ includes, for example, butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, lauryl, myristyl, palmityl, stearyl, oleyl, eicosyl, etc. .

As a typical example of the alkylamine salt of a phosphate represented by the general formula [4], diisooctyl phosphate phosphate / oleyl amine salt ((i-C ₈ H, ₇₀ ) ₂ P (OH ) 0 (C, _B H ₃₅₎ reaction products of NH _2], it can be mentioned key Shiruashi' Dohosufuwe Ichito-Oreiruamin salt to 2- Echiru.

In the composition of the present invention, one type of these phosphorus-based extreme pressure agents may be used, or two or more types thereof may be used in combination. The amount of the extreme pressure agent is based on the total weight of the composition. It is selected in the range of 0.1 to 5% by weight, preferably 0.5 to 4% by weight. If the amount is less than 0.1% by weight, a composition having excellent friction characteristics and anti-abrasion properties cannot be obtained. If the amount exceeds 5% by weight, no improvement in effect is recognized for the amount. Difficult to dissolve.

The phosphorus-based extreme pressure agent of component (C) generally has a large anti-wear effect, and also acts as an auxiliary agent to enhance the effect of the sulfur-based extreme pressure agent. Phosphate improves the friction characteristics and antiwear properties especially at the initial stage (during running-in), and phosphites have the effect of ensuring low friction properties over a long period of time, especially after running-in. In addition, alkylamine salts of phosphoric acid esters are particularly excellent in preventing gear wear.

In the lubricating oil composition of the present invention, various additives conventionally used in lubricating oils such as metal detergents, ashless dispersants, viscosity index improvers, and the like, as long as the object of the present invention is not impaired, Pour point depressants, antioxidants, antioxidants, corrosion inhibitors, defoamers and the like can be added as appropriate.

Examples of the metal detergent include calcium sulfonate, magnesium sulfonate, barium sulfonate, calcium phosphate, barium phosphate and the like, and these are usually used at a ratio of 1 to 5% by weight. Examples of the ashless detergent / dispersant include imidic succinates, succinic amides, benzylamines, boron derivatives thereof, and esters thereof, which are usually used in a ratio of 0.5 to 7% by weight. Used in.

Examples of the viscosity index improver include polymethacrylates, polyisobutylenes, ethylene-propylene copolymers, styrene-butadiene hydrogenated copolymers, etc., which are usually 0.5 to 35% by weight. Used in proportions. Examples of the antioxidant include amine antioxidants such as alkylated diphenylamine, phenyl-1-alpha-naphthylamine and alkylated-naphthylamine, 2,6-di_t-butyl-14-methylphenol, and 4,4 ′ —Phenol-based antioxidants such as methylenebis (2,6-di-t-butylphenol) and the like, which are usually used in a proportion of 0.05 to 2% by weight.

Anti-foaming agents include, for example, alkenyl succinic acid and partial esters thereof. Corrosion inhibitors include, for example, benzotriazole and benzoimidazole. Examples of the agent include dimethylpolysiloxane / polyacrylate, and these can be added as appropriate.

Example

Next, the present invention will be described in more detail with reference to Examples. The present invention is not limited to these Examples.

The friction coefficient (LFW-1), torque transmission efficiency and anti-seizure property (API service classification) of the lubricating oil composition were determined.

(1) Friction coefficient (LFW-1)

Using the tester shown in Fig. 1, Falex S-10 test ring (steel) and Falex H-60 under the conditions of a slip speed of 1.4 mZs, a load of 113 kgf, and an oil temperature of 100 ° C. LFW-1 friction test was performed using a block (steel). In Fig. 1, 1 is the S-10 test ring, 2 is the H-60 block, and 3 is the load applied to the strain gauge _c H-60 block. Detect with a strain gauge and calculate the coefficient of friction. The test oil is soaked up to about half of the ring

(2) Actual machine torque transmission efficiency (%)

The test was conducted under the following conditions: input torque: 3 kgf · m, input speed: 1,000 rpm, oil temperature: 50 ° C, and the torque transmission efficiency () of the actual machine was determined.

(3) Anti-seizure property (API service classification)

Based on the CRC L-42 test, anti-seizure properties were determined. The larger the value, the better the anti-seizure property.

Examples 1-4, Comparative Examples 1-4

A lubricating oil composition containing a base oil (a solvent-refined mineral oil having a viscosity of 11.0 cSt at 100 ° C) and the components and types shown in Table 1 was prepared, and the coefficient of friction (LFW-1) was determined. Actual machine Torque transmission efficiency and seizure prevention were required. Table 1 shows the results.

FIG. 2 is a graph showing the relationship between the input torque and the transmission efficiency of the lubricating oil of the present invention and the SP type compounded oil. Table 1 Example Example Example Example Example Comparative example Comparative example Comparative example Comparative example

1 2 3 4 1 2 3 4 Oxymolybdenum sulfide (hexyl) 2.5 5.0.0 5.0 3.5 ——— 4.0—Hosphorothioate

Oxymolybdenum sulfide- (2-ethyl 4.0 hexyl) dicarbylcarbamate

Additives

Contained ソ isobutylene sulfide 7.0.8.5 7.0 6.5.7.0.6.5-7.0 (wt%)

2-ethylhexyl F, F 3.0 3.0 3.0 1.5 3.5 3.0 2.5 3.0

CD Phosphate I

Rail Rail Phosphite 2.0 2.0 2.5 1.2.5 2.5.2.5 2.2.5 2.5 Rail Rail Phosphate 0,50. 50.5.0.50.5.0.50.5.0.50.5,5 polybutenyl) <^ Imit'0,50.5.0.50.50.5.0.50.5.0.50.50. 5 Friction coefficient (LFW-1) 0.076 0.073 0.073 0.075 0.087 0.085 0.078 0.082 Torque transmission efficiency of actual machine 93.8 94.1 94.3 94.0 92.8 92.8 93.8 93.1 Evaluation (¾)

Anti-seizure property GL-5 GL-5 GL-5 GL-5 GL-5 GL-5 GL-3 GL-4.5

(A p I service m)

As can be seen from Table 1, the lubricating oil composition of the present invention has a lower coefficient of friction (L FW-1) and a higher torque transmission efficiency than actual lubricating oil compositions containing conventional SP additives. And anti-seizure properties are improved.

The invention's effect

The lubricating oil composition for a final reduction gear of the present invention is obtained by combining a base oil with a phosphorus-based extreme pressure agent and a sulfur-based extreme pressure agent in combination with M0DTP, and comprises a conventional SP-based additive. The transmission efficiency of the differential gear under each condition such as input torque, input rotation speed, oil temperature, etc. is further improved compared to the one containing the agent, which contributes to the improvement of fuel efficiency.

Claims

The scope of the claims

1. Based on the total weight of the composition, based on the lubricating base oil (A) — General formula [1]

MO. SPO, [1]

(In the formula, R ¹ and R ² are an alkyl group or an alkenyl group having 4 to 18 carbon atoms, which may be the same or different, and p and q each represent a sum of 4 Is a positive integer such that

Oxymolybdenum sulfide organophosphorodithioate represented by the following formula: 10 to 10% by weight, and (B) at least one sulfur-based extreme pressure agent selected from among olefin sulfides and alkyl sulfides 3 to 15% by weight And (C) 0.1 to 5% by weight of at least one phosphorus-based extreme pressure agent selected from phosphate esters, phosphite esters and alkylamine salts of phosphate esters. A lubricating oil composition for a final reduction gear characterized by the following.

2. The lubricating oil composition for a final reduction gear according to claim 1, wherein the lubricating base oil has a viscosity at 100 ° C. of 3 to 20 cSt.

3. R ¹ and R ² of general formula [1], butyl, pentyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, lauryl, myristyl, palmityl, stearyl, butenyl, pentenyl 2. The lubricating oil composition for a final reducer according to claim 1, wherein the lubricating oil composition is selected from the group consisting of octenyl and oleyl groups.

4. The component (A) is composed of oxymolybdenum dibutyl phosphorodithioate, oxymolybdenum dipentyl phosphorodithioate, oxymolybdenum dihexyl phosphorodithioate, and oxymolybdenum dioctyl phosphorodithioate. Oxymolybdenum disulfide 2-ethylhexylphosphorodithioate, oxymolybdenum didecyl phosphorodithioate, oxymolybdenum dilauryl phosphorodithioate, oxymolybdenum disteayl phosphorodithioate , Oxymolybdenum dibutenyl phosphorodithioate —Oxymolybdenum dipentenyl phosphorodithioate, oxymolybdenum disulfide 2-ethylhexyl phosphorodithioate, oxymolybdenum dioleyl phosphorodithioate and oxymolybdenum dicyclohexyl phosphorodithioate 2. The lubricating oil composition for a final reduction gear according to claim 1, which is selected from the group consisting of ethers.

5. Sulfide olefin force General formula [2]

R ³ — S _x …… [2]

(Wherein, R ³ is an alkenyl group having 4 to 12 carbon atoms, R ⁴ is an alkyl group or an alkenyl group having 4 to 12 carbon atoms, and R ³ and R ⁴ are linear, branched, or cyclic. Where X is an integer from 1 to 8.)

The lubricating oil composition for a final reduction gear according to claim 1, which is a compound represented by the following formula:

6. The lubricating oil composition for a final reduction gear according to claim 1, wherein the lubricating oil composition is a sulfurized diisobutylene.

7. Alkyl sulfide has the general formula [3]

R ⁵ -S _y -R ⁶ …… [3]

(In the formula, R ⁵ and IT are each an alkyl group having 4 to 12 carbon atoms, which may be the same or different, and may be linear, branched, or cyclic. May be, y is an integer from 1 to 8.)

8. The lubricating oil composition for a final reducer according to claim 1, wherein the alkyl sulfide is di-t-butyl disulfide or g-t-butyl trisulfide.

9.Phosphate and phosphite are 0 = P (OR ⁷ ) (OR ⁸ ) (OR ⁹ ), 0 = P (OH) (OR ⁷ ) (OR ⁸ ), 0 = P (OH), (OR ⁷ ), P (OR ⁷ )

(OR ⁸ ) (OR ⁹ ), P (OH) (OR ⁷ ) (OR ⁸ ) or P (OH) (OR ⁷ )

(Wherein, R ⁷ , R ⁸ and R ⁹ are each a linear, branched, or cyclic alkyl or alkenyl group, aryl group or alkyl aryl group having 4 to 30 carbon atoms, and They may be the same or different.)

2. The lubricating oil composition for a final reducer according to claim 1, which is a phosphorus compound represented by the formula:

10. The phosphate and phosphite esters are oleyl acid phosphate, which is a mixture of (C _1B H ₃₅₀ ) P (OH) ₂₀ and (C ₁₈ H ₃₅₀ ) ₂ P (OH) 0, and (C, _fl H ₃₅ 0 P (OH) di O rail hydrogenphosphite phosphine eye bets in a range 1 final reduction gear lubricating oil composition according to claims represented by.

11. The alkylamine salt of a phosphate ester has the general formula [4]

0

II

(R ^{, 0} O) _m P- (OH) ₃ - _m- (NH „R" ₃ - _n ) 3- _m …… [4]

(In the formula, R ^IQ is a linear, branched, or cyclic alkyl or alkenyl group having 4 to 30 carbon atoms, an arylene group or an alkylaryl group, and R ¹ ′ is a carbon atom having 4 to 30 carbon atoms. A linear, branched, or cyclic alkyl or alkenyl group, m and n are each 1 or 2, a plurality of R ′ may be the same or different, and a plurality of R ¹ ′ It may be the same or different.)

2. The lubricating oil composition for a final reduction gear according to claim 1, wherein the lubricating oil composition is represented by:

12. —In formula [4], R ' ^D -butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, lauryl, myristyl, palmityl, stearyl, oleyl, eicosyl, phenyl And cresyl groups; R ¹ 'force; butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, lauryl, myristyl, palmityl, stearyl, oleyl and eicosyl groups The lubricating oil composition for a final reduction gear according to claim 1, which is selected from the group consisting of:

13. alkylamine salts of phosphate esters, reaction of diisopropyl Soo Chi luer Sit Dohosufue one preparative-Oreiruamin salt _{_{[(i- C 8 H 17 0)}} 2 P (OH) 0 and _{_{(C, 8 H 35) NH}} 2 2. The lubricating oil composition for a final reduction gear according to claim 1, which is a product] or 2-ethylhexyl phosphide phosphate amine salt.

14. The lubricating oil composition for a final reduction gear according to claim 1, further comprising various additives commonly used in lubricating oils.

15. The claim wherein the additive is selected from the group consisting of metal detergents, ashless dispersants, viscosity index improvers, pour point depressants, antioxidants, antioxidants, corrosion inhibitors and defoamers. A lubricating oil composition for a final reduction gear according to box 14.