JP6016692B2 - Lubricating oil composition for automatic transmission - Google Patents

Description

  The present invention relates to a lubricating oil composition for an automatic transmission, and more particularly to a lubricating oil composition for a metal belt type continuously variable transmission.

Recent automatic transmissions and continuously variable transmissions are desired to be lighter and smaller, and with the increase in the output of the combined engine, improvement in power transmission capability is being pursued. The purpose of reducing the weight and size is to improve the fuel consumption of a vehicle to be mounted.
In particular, in the case of a metal belt type continuously variable transmission, if the friction coefficient between the belt and the pulley can be improved, the size can be reduced, so that the lubricating oil used there has a characteristic of maintaining a high coefficient of friction between metals. Those are preferred.
Furthermore, the fuel consumption reduction by these lubricating oil is also calculated | required. Specifically, it contributes to the improvement of fuel consumption by reducing the agitation resistance by lowering the viscosity of the lubricating oil and reducing the power loss by reducing the viscous resistance during idling of the wet clutch pack or at the time of fluid lubrication.

  As conventional transmission fluids, friction modifiers, metal detergents, ashless dispersants, anti-wear agents are used to maintain the friction characteristics of the lock-up clutch and maintain the initial anti-shudder performance for a long period of time. Etc. have been proposed (for example, see Patent Documents 1 to 7).

  For example, Patent Document 1 includes a specific calcium salicylate and SP-based extreme pressure agent, a specific amount of a specific succinimide and a boron-containing ashless dispersant, excellent anti-shudder life, and excellent fatigue life. A lubricating oil composition for a transmission having performance has a high intermetal friction coefficient, in which an organic acid metal salt having a specific structure, an antiwear agent, and a boron-containing succinimide are blended as essential components in Patent Document 2. Is a lubricant composition for continuously variable transmissions that achieves both anti-shudder properties and slip control mechanisms. Patent Document 3 contains calcium salicylate, phosphorus-based antiwear agent, friction modifier, and dispersion type viscosity index improver. A lubricating oil composition for a continuously variable transmission that is compatible with a high coefficient of friction between metals and anti-shudder for a slip control mechanism and can be used for a long period of time is disclosed in Patent Document 4. Is a lubricating oil composition with excellent anti-shudder performance and long anti-shudder life, comprising a dithiocarbamate compound, a condensate of a branched chain fatty acid having 8 to 30 carbon atoms and an amine, and an amine-based antioxidant. In Patent Document 5, the anti-shudder life performance of the slip lockup device, in which calcium sulfonate and phosphites, and a sarcosine derivative or a reaction product of a carboxylic acid and an amine are blended, is included. An automatic transmission oil composition having a long life performance with respect to a belt-type CVT device is disclosed in Patent Document 6, which includes a specific amount of a specific alkaline earth metal sulfonate. It has excellent oxidation stability for use as well as anti-shudder performance and long-term use. Automatic transmission fluid composition having long-term durability is disclosed to be. Further, Patent Document 7 discloses an automatic transmission oil having excellent anti-shudder properties and a constant transmission torque capacity, which includes specific amounts of calcium salicylate and magnesium salicylate, specific friction modifiers, and boric acid-modified succinimide. ing.

JP 2003-113391 A JP 2001-323292 A JP 2000-355695 A Japanese Patent Application Laid-Open No. 11-50077 Japanese Patent Laid-Open No. 10-306292 Japanese Patent Laid-Open No. 10-25487 JP 2000-63869 A

  However, when the viscosity is lowered, the oil film in the lubrication part becomes thin, and wear and seizure are likely to occur. Therefore, while maintaining the transmission torque capacity by maintaining a high coefficient of friction between metals, it is suitable as an automatic transmission oil with improved performance to prevent wear and seizure even when the viscosity is lowered, especially as a metal belt type continuously variable transmission oil There is a need for a lubricating oil composition for automatic transmissions.

  As a result of intensive studies to solve the above problems, the present inventors have found that a lubricating oil composition containing a specific boron-containing ashless dispersant and a metal-based detergent in a specific amount and a specific amount ratio can improve the above problems. The headline and the present invention were completed.

That is, the present invention comprises one or a mixture of two or more, at least one of which is a mineral base oil or synthetic oil having a kinematic viscosity of 8 to 14 mm ² / s at 40 ° C. , and the base oil content is 20% by mass. The above-mentioned lubricating base oil, based on the total amount of the lubricating oil composition, (A) a boron-containing ashless dispersant in an amount of 300 to 1000 ppm by mass in terms of boron atoms, and (B) a metal having a total base number of 200 mgKOH / g or more 100-1200 mass ppm in terms of metal atom, and 0.01-5 mass% of (C) amide friction modifier in terms of metal atom, and the content in terms of boron atom of component (A) (Bo: mass) ppm) / (B) component content (M: mass ppm) in terms of metal atoms (Bo / M) is 0.5 to 4 , and the composition has a kinematic viscosity at 40 ° C. of 10 to 30 mm ² / s. , der viscosity index of 160 or more Is a metal belt-type continuously variable transmission lubricating oil composition characterized.

The lubricating oil composition of the present invention is a lubricating oil composition for an automatic transmission that can maintain a high coefficient of friction between metals and is excellent in seizure resistance, and is particularly suitable for a belt-type continuously variable transmission. It is a thing.
The lubricating oil composition of the present invention is also excellent in performance as a transmission oil other than the above, and is used for automatic transmissions such as automobiles, construction machines, and agricultural machines, manual transmissions, and differential gears. Can also be suitably used. In addition, it can be suitably used for industrial gear oils, automobiles such as motorcycles and automobiles, gasoline engines for power generation and marine use, diesel engines, lubricating oils for gas engines, turbine oils, compressor oils, etc. it can.

  The present invention is described in detail below.

  In the lubricating oil composition of the present invention, at least a boron-containing ashless dispersant as the component (A), a metallic detergent as the component (B), and a friction modifier as the component (C) are added to the lubricating base oil. It contains.

  The lubricating base oil in the lubricating oil composition for automatic transmissions of the present invention (hereinafter simply referred to as “lubricating oil composition”) is not particularly limited, and is a mineral base oil used for ordinary lubricating oil. Synthetic oil base oils can be used.

  Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Refined by performing one or more treatments such as hydroisomerization, solvent dewaxing, hydrorefining, etc., or base oil produced by isomerizing wax isomerized mineral oil, GTL WAX (gas-trimmed wax), etc. Can be illustrated.

  The mineral oil base oil in the present invention is preferably a hydrocracked mineral oil base oil. Further, a wax isomerized isoparaffin base oil obtained by isomerizing a raw material containing 50% by mass or more of a wax such as petroleum-based or Fischer-Tropsch synthetic oil is more preferably used. These can be used alone or in any mixture, but it is preferable to use a wax isomerized base oil alone.

  Specific examples of the synthetic base oil include polybutene or hydrides thereof; poly-α-olefins such as 1-octene oligomers, 1-decene oligomers and 1-dene oligomers or hydrides thereof; ditridecyl glutarate, Diesters such as di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; neopentyl glycol ester, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexa Examples include polyol esters such as noate and pentaerythritol pelargonate; aromatic synthetic oils such as alkylnaphthalene, alkylbenzene, and aromatic esters, or mixtures thereof.

The kinematic viscosity at 100 ° C. of the lubricating base oil used in the present invention is not particularly limited, but is preferably 2 mm ² / s or more, more preferably 2.5 mm ² / s or more, and particularly preferably 3 mm ² / s or more. Further, it is preferably adjusted to 8 mm ² / s or less, more preferably 6 mm ² / s or less, further preferably 4.5 mm ² / s or less, and particularly preferably 4 mm ² / s or less. When the kinematic viscosity at 100 ° C. of the lubricating base oil exceeds 8 mm ² / s, the low-temperature viscosity characteristics deteriorate, whereas when the kinematic viscosity is less than 2 mm ² / s, oil film formation at the lubrication site is not possible. Since it is sufficient, the lubricity is inferior, and the evaporation loss of the lubricating base oil increases, which is not preferable.
Here, the kinematic viscosity at 100 ° C. refers to the kinematic viscosity at 100 ° C. defined in ASTM D-445.

Further, the kinematic viscosity at 40 ° C. of the lubricating base oil used in the present invention is not particularly limited, but is preferably 8.0 mm ² / s or more, more preferably 8.5 mm ² / s or more, and particularly preferably 9.0 mm ^2. / S or more. Further, it is preferably adjusted to 40 mm ² / s or less, more preferably 30 mm ² / s or less, further preferably 25 mm ² / s or less, and particularly preferably 20 mm ² / s or less. When the kinematic viscosity at 40 ° C. of the lubricating base oil exceeds 40 mm ² / s, the low-temperature viscosity characteristics deteriorate, whereas when the kinematic viscosity is less than 8.0 mm ² / s, an oil film is formed at the lubrication point. Is inadequate in lubricity, and the evaporation loss of the lubricating base oil is increased.
Here, the kinematic viscosity at 40 ° C. refers to the kinematic viscosity at 40 ° C. defined in ASTM D-445.

  The viscosity index of the lubricating base oil is not particularly limited, but is preferably 100 or more, more preferably 120 or more, further preferably 130 or more, particularly preferably 140 or more, usually 200 or less, preferably 160 or less. By setting the viscosity index to 100 or more, it is possible to obtain a composition exhibiting favorable viscosity characteristics from a low temperature to a high temperature. On the other hand, if the viscosity index is too high, the viscosity at low temperatures tends to increase, which is not preferable.

  As the lubricating base oil in the present invention, the mineral base oil, the synthetic base oil, or an arbitrary mixture of two or more selected from these can be used. Examples thereof include one or more mineral oil base oils, one or more synthetic oil base oils, a mixed oil of one or more mineral oil base oils and one or more synthetic oil base oils, and the like.

In the present invention, for improving the low-temperature viscosity characteristics and viscosity index of the lubricating oil composition, a low viscosity base oil kinematic viscosity of 8 to 14 mm ² / s at 40 ° C., or a kinematic viscosity at 40 ° C. 8 to 14 mm ² A mixed base oil composed of a combination of a low-viscosity base oil of / s and a base oil having a relatively high viscosity and two or more base oils is preferably used. When this mixed base oil is used, the blending ratio of the base oil having a kinematic viscosity at 40 ° C. of 8 to 14 mm ² / s is preferably at least 20 mass%, preferably 40 mass% or more.

The low viscosity base oil, a kinematic viscosity of 8 to 14 mm ² / s at 40 ° C., preferably 9 to 12 mm ² / s, kinematic viscosity at 100 ° C. is ^{2 mm} 2 / s or more 3.5 mm ² / s Is less than.
On the other hand, the relatively high viscosity base oil has a kinematic viscosity at 40 ° C. of 15 to 25 mm ² / s and a kinematic viscosity at 100 ° C. of 3.5 mm ² / s to 4.5 mm ² / s.
The viscosity index can be improved by mixing the low viscosity base oil and the relatively high viscosity base oil.

  The aforementioned low viscosity base oil preferably has a viscosity index of 110 or more, more preferably 120 or more, and further preferably 125 or more. The viscosity index of the base oil having a relatively high viscosity is preferably 125 or more, more preferably 130 or more, and further preferably 135 or more.

  Further, the sulfur content of the lubricating base oil used in the present invention is not particularly limited, but is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and 0.005% by mass. % Or less is more preferable, 0.001% by mass or less is particularly preferable, and substantially 0 is most preferable. A composition superior in oxidation stability can be obtained by reducing the sulfur content of the lubricating base oil.

The lubricating oil composition of the present invention contains a boron-containing ashless dispersant as the component (A).
Examples of the boron-containing ashless dispersant include a boronated ashless dispersant obtained by boronating an ashless dispersant.

Examples of the ashless dispersant include the following nitrogen compounds. These can be used alone or in combination of two or more.
(A1) A succinimide having at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof (A2) linear or branched having 40 to 400 carbon atoms Benzylamine having at least one alkyl group or alkenyl group in the molecule, or a derivative thereof (A3) having at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule Polyamine or its derivatives

The alkyl group or alkenyl group has 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms. When the carbon number of the alkyl group or alkenyl group is less than 40, the solubility of the compound in the lubricating base oil decreases, whereas when the carbon number of the alkyl group or alkenyl group exceeds 400, the low temperature fluidity of the composition Are worse, respectively.
This alkyl group or alkenyl group may be linear or branched, but specifically, preferred are derived from olefin oligomers such as propylene, 1-butene and isobutylene, and co-oligomers of ethylene and propylene. And a branched alkyl group and a branched alkenyl group.

  More specifically, examples of (A1) succinimide include compounds represented by the following general formula (1) or (2).

In the general formula (1), R ¹ represents an alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and a represents an integer of 1 to 5, preferably 2 to 4.
In the general formula (2), R ² and R ³ each independently represents an alkyl group or an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and b is 0 to 4, preferably 1 to 3. Indicates an integer.

  In the succinimide, a so-called monotype succinimide represented by the general formula (1) in which succinic anhydride is added to one end of the polyamine is added by imidization, and succinic anhydride is added to both ends of the polyamine. A so-called bis-type succinimide represented by the general formula (2) in the form is included, and any of them or a mixture thereof can be used in the composition of the present invention.

  The method for producing these succinimides is not particularly limited. For example, alkyl succinic acid or alkenyl succinic acid obtained by reacting a compound having an alkyl group or alkenyl group having 40 to 400 carbon atoms with maleic anhydride at 100 to 200 ° C. It can be obtained by reacting an acid with a polyamine. Specific examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

More specifically, examples of (A2) benzylamine include compounds represented by the following general formula (3).

In the general formula (3), R ¹ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and r represents an integer of 1 to 5, preferably 2 to 4.

  The method for producing this benzylamine is not limited in any way. For example, after reacting a polyolefin such as propylene oligomer, polybutene, and ethylene-α-olefin copolymer with phenol to form alkylphenol, formaldehyde and It can be obtained by reacting polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine by Mannich reaction.

More specifically, examples of (A3) polyamine include compounds represented by the following general formula (4).
R ¹ —NH— (CH ₂ CH ₂ NH) _k —H (4)

In the general formula (4), R ¹ represents an alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and k represents an integer of 1 to 5, preferably 2 to 4.

  Although the production method of this polyamine is not limited at all, for example, after chlorinating polyolefin such as propylene oligomer, polybutene, and ethylene-α-olefin copolymer, ammonia, ethylenediamine, diethylenetriamine, triethylene are added thereto. It can be obtained by reacting polyamines such as tetramine, tetraethylenepentamine, and pentaethylenehexamine.

Boronation of the ashless dispersant is generally performed by allowing boric acid or the like to act on the above-mentioned nitrogen-containing compound and neutralizing a part or all of the remaining amino group and / or imino group.
For example, methods for producing boric acid-modified succinimide are disclosed in JP-B-42-8013 and JP-A-42-8014, JP-A-51-52381, JP-A-51-130408, and the like. And the like. Specifically, for example, organic compounds such as alcohols, hexane, xylene, etc., light lubricating oil base oil, polyamine and polyalkenyl succinic acid (anhydride), boric acid, boric acid ester, or boron compounds such as borate Can be obtained by mixing and heat-treating under appropriate conditions.

In the present invention, as long as the boron-containing ashless dispersant contains the amount of boron required in the present invention as a lubricating oil composition, the boron-containing ashless dispersant is a non-borated ashless dispersant for improving stability as a composition. You may use together.
However, in order to achieve the wear resistance and seizure resistance, which are the objects of the present invention, a boron-containing ashless dispersant alone is preferable.

In the present invention, the boron-containing ashless dispersant is preferably a boronated succinimide in terms of stability as a compound thereof.
The molecular weight of the hydrocarbon group of the boronated succinimide is preferably 500 or more, more preferably 700 or more, and still more preferably 900 or more in terms of weight average molecular weight. Moreover, 2000 or less is preferable and 1500 or less is more preferable. If it is less than 500, the friction coefficient is high and the fuel saving effect is small. On the other hand, if it exceeds 2000, it is substantially difficult to synthesize.

In the present invention, the boron content of the boron-containing ashless dispersant is preferably 1.0% by weight or more, and more preferably 1.5% by weight or more. Further, it is preferably 3% by weight or less, more preferably 2.5% by weight or less, and particularly preferably 2.4% by weight or less.
If the boron content is less than 1.0% by weight, the wear resistance and seizure resistance, which are the objects of the present invention, may not be achieved. On the other hand, if the amount exceeds 3% by weight, the composition may be precipitated and the stability may be lost.

In the present invention, the nitrogen content of the boron-containing ashless dispersant is preferably 1.0% by weight or more, and more preferably 1.5% by weight or more. Further, it is preferably 3% by weight or less, more preferably 2.5% by weight or less, and particularly preferably 2.0% by weight or less.
When the nitrogen content is less than 1.0% by weight, there is a possibility that the boronation which is the object of the present invention cannot be sufficiently performed. On the other hand, if it exceeds 3% by weight, there is a possibility that the composition will rather deteriorate the abrasion resistance.

  The content of the component (A) in the present invention needs to be 300 mass ppm or more, preferably 400 mass ppm or more, more preferably 600 mass ppm, in terms of boron atom, based on the total amount of the lubricating oil composition. That's it. Moreover, the upper limit is 1000 mass ppm or less, it is preferable that it is 900 mass ppm or less, 850 mass ppm or less is more preferable, and 800 mass ppm or less is the most preferable. If it is less than 300 mass ppm, the extreme pressure property is poor, and if it exceeds 1000 mass ppm, the friction material is adversely affected, and the shudder prevention life is shortened. In addition, there is concern about the occurrence of precipitation and the like, and there is a risk of lack of stability.

Moreover, the lubricating oil composition of the present invention contains a metallic detergent having a total base number of 200 mgKOH / g or more as the component (B).
The total base number referred to here is JIS K2501 “Petroleum products and lubricating oils—Test method for neutralization number”. It means the total base number measured by the perchloric acid method based on

  Specific examples of the metallic detergent include alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate, and one or more kinds of metallic detergents selected from these can be mentioned. An agent can be used. Of these, calcium salts are preferred in terms of friction characteristics.

  More specifically, the alkaline earth metal sulfonate is an alkaline earth metal salt of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a molecular weight of 100 to 1500, preferably 200 to 700, for example. Can be mentioned. Particularly preferred are magnesium salts and / or calcium salts. Of these, calcium salts are preferred in terms of friction characteristics. Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

  More specifically, the alkaline earth metal phenate is an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and reacting the alkylphenol with sulfur. Or an alkaline earth metal salt of a Mannich reaction product of alkylphenol obtained by reacting the alkylphenol with formaldehyde. Particularly preferred are magnesium salts and / or calcium salts.

  More specifically, the alkaline earth metal salicylate is an alkaline earth metal salt of an alkyl salicylic acid having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. Can be mentioned. Particularly preferred are magnesium salts and / or calcium salts.

In the alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate, Mannich reaction of alkyl aromatic sulfonic acid, alkylphenol, alkylphenol sulfide, alkylphenol as long as the total base number is 200 mgKOH / g or more Products, alkylsalicylic acid, etc. are directly reacted with alkaline earth metal bases such as magnesium and / or calcium alkaline earth metal oxides and hydroxides, or once alkali metal salts such as sodium salts and potassium salts In addition to neutral salts (normal salts) obtained by substituting with alkaline earth metal salts, etc., these neutral salts (normal salts) and excess alkaline earth metal salts or alkaline earth metal bases ( Alkaline earth metal hydroxides and oxides) A basic salt obtained by heating in the presence, or an overbased salt obtained by reacting a neutral salt (normal salt) with an alkaline earth metal base in the presence of carbon dioxide (superbasic salt) ) Is also included.
These reactions are usually performed in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricant base oil, or the like). Further, metal detergents are usually marketed in a state diluted with a light lubricating base oil or the like, and are also available, but generally the metal content is 1.0 to 20% by mass, It is desirable to use 2.0 to 16% by mass.
The metal detergent used in the present invention is preferably an overbased salt.

  The content of the component (B) in the present invention is required to be 100 ppm by mass or more, preferably 200 ppm by mass or more, more preferably 300 ppm by mass in terms of metal element, based on the total amount of the lubricating oil composition. As mentioned above, More preferably, it is 350 mass ppm or more. Preferably, it is 1200 mass ppm or less, more preferably 1000 mass ppm or less, still more preferably 800 mass ppm or less, particularly preferably 600 mass ppm or less, and most preferably 450 mass ppm or less. If it is less than 100 ppm by mass, the effect of improving the friction characteristics tends to be insufficient. On the other hand, if it exceeds 1200 ppm by mass, there is a concern that the friction characteristics may be deteriorated due to the adverse effect of the wet clutch on the friction material.

  The metallic detergent of the present invention is preferably calcium sulfonate. It is preferable to use calcium sulfonate alone. This is because the friction properties of calcium sulfonate are the best match with the friction properties required for the present invention.

  In the lubricating oil composition of the present invention, it is important that the content of the component (A) and the content of the component (B) are in a specific range. That is, based on the total amount of the lubricating oil composition, the ratio of the content of the component (A) in terms of boron atom (Bo: mass ppm) / the content in terms of metal atom of the component (B) (M: mass ppm) (Bo / M) must be 0.5-4. The lower limit of Bo / M is 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, and particularly preferably 1.0 or more. The upper limit is 4 or less, preferably 3.5 or less, more preferably 3 or less, further preferably 2.5 or less, and particularly preferably 2 or less. When Bo / M is less than 0.5, the effect of improving the coefficient of friction between metals becomes insufficient. On the other hand, when it exceeds 4, the effect of improving the coefficient of friction between metals becomes insufficient.

Moreover, the lubricating oil composition of the present invention contains a friction modifier as the component (C).
As the friction modifier, any compound usually used as a friction modifier in the lubricating oil field can be used, but an alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly a linear alkyl group having 6 to 30 carbon atoms. Alternatively, amine compounds, imide compounds, fatty acid esters, fatty acid amides, fatty acid metal salts, and the like having at least one linear alkenyl group in the molecule are preferably used.

  Examples of the amine compound include linear or branched, preferably linear aliphatic monoamines having 6 to 30 carbon atoms, linear or branched, preferably linear aliphatic polyamines, or fatty acids thereof. An alkylene oxide adduct of a group amine can be exemplified.

  Examples of the imide compound include a succinimide having a linear or branched alkyl group or alkenyl group having 6 to 30 carbon atoms and / or a modified compound thereof using carboxylic acid, boric acid, phosphoric acid, sulfuric acid, or the like. .

  Examples of fatty acid esters include esters of linear or branched, preferably linear, fatty acids having 7 to 31 carbon atoms with aliphatic monohydric alcohols or aliphatic polyhydric alcohols. Examples of fatty acid amides include amides of linear or branched, preferably linear fatty acids having 7 to 31 carbon atoms, and aliphatic monoamines or aliphatic polyamines.

  Examples of the fatty acid metal salt include an alkaline earth metal salt (magnesium salt, calcium salt, etc.) or zinc salt of a linear or branched, preferably linear fatty acid having 7 to 31 carbon atoms.

  In the present invention, among these, it is preferable to contain one or two selected from amine-based friction modifiers, ester-based friction modifiers, amide-based friction modifiers, fatty acid-based friction modifiers, and fatigue. It is particularly preferable to contain one or more selected from amine-based friction modifiers, fatty acid-based friction modifiers, and amide-based friction modifiers in that the life can be further improved. Further, when the lubricating oil composition for a drive transmission device of the present invention is used as a lubricating oil for an automatic transmission or a continuously variable transmission, an imide-based friction modifier can be remarkably improved in a shudder prevention life. It is particularly preferable to contain.

  The content of the friction modifier is 0.01% by mass or more based on the total amount of the composition, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and most preferably 0.3% by mass or more. . Moreover, it is 5 mass% or less, Preferably it is 3 mass% or less, More preferably, it is 1 mass%, More preferably, it is 0.5 mass% or less. If it is less than 0.01% by mass, it will be difficult to ensure the necessary anti-shudder properties. If it exceeds 5% by mass, the necessary coefficient of friction between metals may not be ensured.

  The lubricating oil composition of the present invention preferably further contains a phosphorus additive as the component (D). By adding the component (D), it is possible to improve the wear resistance and seizure resistance, and the friction characteristics of the wet clutch.

  As the phosphorus-based additive of component (D), for example, zinc alkyldithiophosphate, phosphoric acid, phosphorous acid, phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid triesters, phosphorous acid monoesters, Phosphite diesters, phosphite triesters, salts of (phosphite) esters, and mixtures thereof.

  Among the components (D) listed here, those other than phosphoric acid and phosphorous acid are usually compounds containing a hydrocarbon group having 2 to 30 carbon atoms, preferably 3 to 20 carbon atoms. Specifically, examples of the hydrocarbon group having 2 to 30 carbon atoms include the following alkyl groups, cycloalkyl groups, alkyl-substituted cycloalkyl groups, alkenyl groups, aryl groups, alkyl-substituted aryl groups, and aryl-substituted alkyls. The group can be mentioned. These alkyl groups may be linear or branched.

In addition, as the salt of the (phosphite) esters described above, specifically, phosphoric acid monoester, phosphoric acid diester, phosphorous acid monoester, phosphorous acid diester, etc., ammonia or carbon number of 1-8. And a salt obtained by neutralizing a part or all of the remaining acidic hydrogen by reacting a nitrogen-containing compound such as an amine compound containing only a hydrocarbon group or a hydroxyl group-containing hydrocarbon group in the molecule.
One type or two or more types of these components (D) can be arbitrarily blended.

  In the present invention, alkyl or alkenyl phosphites are preferred. In particular, alkyl phosphate esters having 8 or less carbon atoms, more preferably 5 or less carbon atoms are preferred.

Moreover, in this invention, it is preferable to use together phosphorous acid and an alkyl or alkenyl phosphite.
When phosphorous acid and alkyl or alkenyl phosphite are used in combination, the ratio of phosphorous acid: alkyl or alkenyl phosphite is 1: 0.2 to 1: 3.5 in the ratio of phosphorus amount. preferable. More preferably, it is 1: 0.5-1: 3, More preferably, it is 1: 1-1: 2. If the ratio of phosphorous acid is less than 0.2 or exceeds 10, there is a concern that the balance between the coefficient of friction between metals and the anti-shudder performance deteriorates.

When the component (D) is blended in the lubricating oil composition of the present invention, the blending amount is not particularly limited, but in order to obtain the effect of improving the friction coefficient of the wet clutch and the excellent oxidation stability of the lubricating oil composition, lubrication On the basis of the total amount of the oil composition, the phosphorus amount is preferably 50 ppm by mass or more, more preferably 100 ppm by mass or more, further preferably 200 ppm by mass or more, and most preferably 400 ppm by mass or more. Further, it is preferably 2000 ppm by mass or less, more preferably 1500 ppm by mass or less, further preferably 1000 ppm by mass or less, particularly preferably 800 ppm by mass or less, and most preferably 600 ppm by mass or less.
When the amount of phosphorus is less than 50 ppm by mass, the wear resistance and the friction coefficient between metals are not sufficient, and the anti-shudder characteristics are insufficient. On the other hand, if it exceeds 2000 ppm by mass, there is a concern about oxidation stability and adverse effects on the sealing material.

  In the lubricating oil composition of the present invention, an extreme pressure additive other than the phosphorus additive of component (D) can be used in combination. As the extreme pressure additive that can be used in combination, any compound that is usually used as an extreme pressure additive for lubricating oils can be used. Examples of these include sulfur compounds such as disulfides, sulfurized olefins, and sulfurized fats and oils. One or two or more compounds arbitrarily selected from these extreme pressure additives can be blended in any amount. The amount of these extreme pressure additives is usually 0.01 to 5.0% by mass based on the total amount of the lubricating oil composition.

The lubricating oil composition of the present invention preferably contains a viscosity index improver as the component (E). As the viscosity index improver, specifically, a so-called non-dispersion type viscosity index improvement such as a polymer of one or more monomers selected from various methacrylic esters, a copolymer, or a hydrogenated product thereof is used. Examples thereof include so-called dispersion-type viscosity index improvers obtained by copolymerization of various methacrylic acid esters containing a nitrogen compound.
Further, specific examples of other viscosity index improvers include non-dispersed or dispersed ethylene-α-olefin copolymers (the α-olefin can be exemplified by propylene, 1-butene, 1-pentene, etc.) and hydrogen thereof. And a hydrogenated product of styrene-diene copolymer, styrene-maleic anhydride copolymer, and polyalkylstyrene.

The molecular weight of these viscosity index improvers is selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is, for example, 5,000 to 150,000, preferably 5,000 to 35,000 in the case of dispersed and non-dispersed polymethacrylates. In the case of isobutylene or a hydride thereof, 800 to 5,000, preferably 1,000 to 4,000, and in the case of an ethylene-α-olefin copolymer or a hydride thereof, 800 to 150,000, preferably The thing of 3,000-12,000 is preferable. Further, among these viscosity index improvers, when an ethylene-α-olefin copolymer or a hydride thereof is used, a lubricating oil composition particularly excellent in shear stability can be obtained. In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be blended in any amount. The blending amount of the viscosity index improver is usually in the range of 0.1 to 40% by mass based on the total amount of the lubricating oil composition.

  The viscosity index improver in the present invention is preferably a methacrylate polymer or copolymer, that is, polymethacrylate. This is because polymethacrylate as a viscosity index improver has a high low temperature viscosity characteristic and a high viscosity index improvement effect.

The molecular weight is more preferably 5,000 to 100,000 as the weight average molecular weight, more preferably 10,000 or more, and more preferably 70,000 or less. Furthermore, it is preferable to combine those having a weight average molecular weight of 5,000 or more and less than 30,000 with those having a weight average molecular weight of 30,000 or more and 70,000 or less. Those of 30,000 to 70,000 are preferably 60,000 or less.
When a weight average molecular weight of 5,000 or more and less than 30,000 is combined with one having a weight average molecular weight of 30,000 or more and 70,000 or less, the weight ratio as an additive is 5,000 or more and less than 30,000: 30, It is preferable that 000 or more and 70,000 or less are 1: 0.02-1: 1. More preferably, it is 1: 0.05-1: 0.8, More preferably, it is 1: 0.1-1: 0.5.
The reason why the two types of polymethacrylates are combined is that the balance between shear stability, low temperature viscosity characteristics, and viscosity index improvement effect is the best in the present invention.

  In the lubricating oil composition of the present invention, in addition to the above additives, an antioxidant, a corrosion inhibitor, a rust inhibitor, a demulsifier, and a metal deactivator, if necessary, for the purpose of further improving the performance. You may mix | blend various additives, such as an agent, a pour point depressant, a rubber swelling agent, an antifoamer, and a coloring agent, individually or in combination.

Examples of the antioxidant that can be used in combination with the lubricating oil composition of the present invention include those commonly used in lubricating oils such as phenolic compounds and amine compounds. Specifically, for example, alkylphenols such as 2,6-di-tert-butyl-4-methylphenol; methylene-4,4-bisphenol (2,6-di-tert-butyl-4-methylphenol) and the like Bisphenols; naphthylamines such as phenyl-α-naphthylamine; dialkyldiphenylamines; zinc dialkyldithiophosphates such as zinc di-2-ethylhexyldithiophosphate; and (3,5-di-tert-butyl-4-hydroxyphenyl ) Esters of fatty acids (propionic acid etc.) and mono- or polyhydric alcohols such as methanol, octadecanol, 1,6 hexadiol, neopentyl glycol, thiodiethylene glycol, triethylene glycol, pentaerythritol and the like. One or two or more compounds arbitrarily selected from these antioxidants can be blended in any amount. In the present invention, it is preferable to use an amine compound and a phenol compound in combination.

  Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds.

  Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of metal deactivators include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Examples include dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile.

  As the pour point depressant, a known pour point depressant can be arbitrarily selected according to the lubricating base oil. As the pour point depressant, for example, a poly (meth) acrylate pour point having a weight average molecular weight of 50,000 to 300,000, preferably 60,000 to 300,000, particularly preferably 100,000 to 250,000. A depressant is preferably used.

  As the antifoaming agent, any compound usually used as an antifoaming agent in the lubricating oil field can be used, and examples thereof include silicones such as dimethyl silicone and fluorosilicone. One or two or more compounds arbitrarily selected from these can be blended in any amount.

  As the colorant, any compound that is usually used can be used, and any amount can be blended. Usually, the blending amount is 0.001 to 1.0% by mass based on the total amount of the composition. is there.

  When these additives are contained in the lubricating oil composition of the present invention, the content is 0.005 to 5 for each of the antioxidant, corrosion inhibitor, rust inhibitor, and demulsifier, based on the total amount of the composition. % By weight, 0.005 to 1% by weight for metal deactivator, 0.05 to 1% by weight for pour point depressant, 0.0005 to 1% by weight for antifoam, 0.001 to 1 for colorant. It is usually selected in the range of 1% by mass.

Further, the kinematic viscosity at 100 ° C. of the lubricating oil composition of the present invention is preferably 4 mm ² / s or more, more preferably 4.5 mm ² / s or more, further preferably 5 mm ² / s or more, and particularly preferably 5. 5 mm ² s or more, most preferably 6 mm ² / s or more. Further, it is preferably 9 mm ² / s or less, more preferably 8 mm ² / s or less, further preferably 7.5 mm ² / s or less, particularly preferably 7 mm ² / s or less, and most preferably 6.5 mm ² / s or less. .
If the kinematic viscosity is less than 4 mm ² / s, a sufficient oil film thickness may not be formed, and the wear resistance may be insufficient. If it exceeds 9 mm ² / s, a sufficient fuel saving effect is obtained. Not only is this not possible, but the startability at low temperatures may be insufficient.

Further, the kinematic viscosity at 40 ° C. of the lubricating oil composition of the present invention is preferably 10 mm ² / s or more, more preferably 12 mm ² / s or more, and further preferably 15 mm ² / s or more. Moreover, Preferably it is 30 mm < ² > / s or less, More preferably, it is 25 mm < ² > / s or less, More preferably, it is 20 mm < ² > / s or less.
If the kinematic viscosity is less than 10 mm ² / s, a sufficient oil film thickness may not be formed, and abrasion resistance may be insufficient, and if it exceeds 30 mm ² / s, fuel economy is significantly reduced. Each is not preferred.

  Further, the BF viscosity at −40 ° C. of the lubricating oil composition of the present invention is preferably 20,000 mPa · s or less, more preferably 15,000 mPa · s or less, still more preferably 10,000 mPa · s or less, particularly preferably. It is 8,000 mPa · s or less, and most preferably 7,000 mPa · s or less. When the BF viscosity exceeds 20,000 mPa · s, the startability at low temperatures tends to be insufficient.

  Further, the viscosity index of the lubricating oil composition of the present invention is preferably 160 or more, more preferably 180 or more, further preferably 200 or more, and most preferably 210 or more. Further, it is preferably 300 or less, more preferably 250 or less, and still more preferably 230 or less. If the viscosity index is less than 160, fuel economy tends to be insufficient. Moreover, the composition exceeding 300 has too much content of the poly (meth) acrylate viscosity index improver, and tends to have insufficient shear stability.

  The lubricating oil composition for an automatic transmission according to the present invention is suitably used for a continuously variable transmission using a metal belt. It is particularly suitable for a continuously variable transmission using a chain belt type metal belt.

  Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Examples 1-18 and Comparative Examples 1-7)
The lubricating oil compositions shown in Examples 1 to 18 and Comparative Examples 1 to 7 in Table 1 were prepared, the tests shown below were conducted, and the evaluation results were also shown in Table 1. In Table 1, the ratio of the base oil is based on the total amount of the base oil, and the amount of each additive added is based on the total amount of the composition.

(1) Initial seizure load (LNSL) by the high-speed four-ball test method based on ASTM D2783
(2) Wear scar diameter by high-speed four-ball test method compliant with ASTM D4172 (3) Seizure load by Falex galling test method compliant with ASTM D3233 (4) LFW-compliant with JASO method (high load method) M358: 2005 Coefficient of friction between metals by one test (5) Shader life test based on LVFA life test method based on JASO method M349: 2010

As is apparent from Table 1, Comparative Example 1 in which the boron / metal (Bo / M) ratio is 7.0 and Comparative Example 7 in which 5.0 is used are compared to the examples, and the inter-metal friction of LFW-1 The coefficient is low.
Moreover, the comparative example 2 whose boron / metal (Bo / M) ratio is 0.4 has a low coefficient of friction between metals of LFW-1 compared with an Example.
Moreover, the comparative example 3 which uses the calcium sulfonate whose base number is 70 mgKOH / g has a low metal-to-metal friction coefficient of LFW-1 compared with an Example. In addition, wear resistance and seizure resistance are insufficient.
Further, even when using an ashless dispersant containing boron, Comparative Example 4 and Comparative Example 5 in which the boron content is 200 ppm by mass, and Comparative Example 6 in which the boron content is 1200 ppm by mass are compared with the Examples. LFW-1 has a low coefficient of friction between metals. In addition, wear resistance and seizure resistance are insufficient. Moreover, the friction coefficient between metals of LFW-1 is also low, and it has influenced the transmission torque capacity.

Claims (4)

A lubricating oil comprising one or a mixture of two or more, wherein at least one is a mineral base oil or synthetic oil having a kinematic viscosity of 8 to 14 mm ² / s at 40 ° C. , and the base oil content is 20% by mass or more. Base metal, based on the total amount of the lubricating oil composition, (A) a boron-containing ashless dispersant, 300 to 1000 ppm by mass in terms of boron atom, and (B) a metal detergent with a total base number of 200 mgKOH / g or more 100-1200 mass ppm in terms of atom, and 0.01-5 mass% of (C) amide friction modifier, and the content in terms of boron atom of component (A) (Bo: mass ppm) / (B ) The ratio (Bo / M) of the content (M: mass ppm) of the component in terms of metal atoms is 0.5 to 4 , the kinematic viscosity at 40 ° C. of the composition is 10 to 30 mm ² / s, and the viscosity index is 160. Kim, characterized in that at least Lubricating oil composition for genus belt type continuously variable transmission. Furthermore, (D) phosphorus additive is 50-2000 mass ppm as phosphorus amount on the basis of the total amount of lubricating oil composition, and (E) viscosity index improver is contained in 0.1-40% by mass on the basis of the total amount of lubricating oil composition. The lubricating oil composition for a metal belt type continuously variable transmission according to claim 1 . The lubricating oil composition for a metal belt type continuously variable transmission according to claim 1 or 2 , wherein the (A) boron-containing ashless dispersant contains 1 wt% or more of boron and 3 wt% or less of nitrogen. object. The lubricating oil composition for a metal belt type continuously variable transmission according to any one of claims 1 to 3 , wherein the (B) metallic detergent consists only of calcium sulfonate.