阅读说明：本技术 润滑油组合物 (Lubricating oil composition ) 是由 武川大辅 于 2019-02-22 设计创作，主要内容包括：本发明涉及润滑油组合物、填充该润滑油组合物而成的无级变速器、以及包括使用该润滑油组合物的在无级变速器中控制摩擦的方法。本发明的润滑油组合物的特征在于,其包含(A)基础油、(B)二胺、(C)乙醇酰胺以及(D)亚磷酸酯。根据本发明的优选方案,本发明的润滑油组合物能够兼顾在不同部位间的不同摩擦特性,因而可适合作为变速器用润滑油、尤其金属带式的无级变速器用润滑油使用。(The present invention relates to a lubricating oil composition, a continuously variable transmission filled with the lubricating oil composition, and a method for controlling friction in a continuously variable transmission comprising using the lubricating oil composition. The lubricating oil composition of the present invention is characterized by comprising (A) a base oil, (B) a diamine, (C) an ethanolamide, and (D) a phosphite. According to a preferred embodiment of the present invention, the lubricating oil composition of the present invention can achieve both of different friction characteristics between different portions, and therefore can be suitably used as a lubricating oil for transmissions, particularly a lubricating oil for metal belt type continuously variable transmissions.)

1. A lubricating oil composition comprising (A) a base oil, (B) a diamine, (C) an ethanolamide, and (D) a phosphite.

2. The lubricating oil composition according to claim 1, wherein the content of the diamine (B) is 0.03 to 0.1 mass%, based on the total amount of the composition.

3. The lubricating oil composition according to claim 1 or 2, wherein the content of (C) the ethanolamide is 0.1 to 3 mass%, based on the total amount of the composition.

4. The lubricating oil composition according to any one of claims 1 to 3, wherein the content of (D) phosphite is 0.05 to 2 mass%, based on the total amount of the composition.

5. The lubricating oil composition according to any one of claims 1 to 4, having a kinematic viscosity at 100 ℃ of 2mm²More than s and 20mm²The ratio of the water to the water is less than s.

6. The lubricating oil composition according to any one of claims 1 to 5, wherein the content of the fatty amide is less than 0.04% by mass based on the total amount of the composition.

7. The lubricating oil composition according to any one of claims 1 to 6, which is used for a transmission.

8. A continuously variable transmission filled with the lubricating oil composition according to any one of claims 1 to 7.

9. A method of controlling friction in a continuously variable transmission, comprising using the lubricating oil composition according to any one of claims 1 to 7.

Technical Field

The present invention relates to a lubricating oil composition, a method for controlling friction in a continuously variable transmission, and a continuously variable transmission filled with the lubricating oil composition.

Background

In recent years, as a Transmission used in automobiles and the like, a Continuously Variable Transmission (CVT) of a metal belt type, a chain type, a ring type, and the like has been developed and put into practical use. In these continuously variable transmissions, lubricating oil for automatic transmissions was used as lubricating oil. However, as the performance of the continuously variable transmission improves, more excellent performance is becoming required for the lubricating oil. In particular, since the friction characteristics of the lubricating oil used for the wet clutch of the automatic transmission have been optimized for the automatic transmission, there is a problem that the intermetallic friction coefficient tends to be insufficient and large-capacity torque transmission is difficult when the lubricating oil is transferred to the continuously variable transmission.

Therefore, various lubricating oils have been developed for continuously variable transmissions. For example, proposed are: a lubricating oil composition containing (a) an alkaline earth metal sulfonate or phenate, (b) an imide compound, and (c) a phosphorus compound (see patent document 1); disclosed is a lubricating oil composition which is obtained by compounding (A) at least one phosphorus-containing compound selected from the group consisting of phosphoric monoesters, phosphoric diesters and phosphorous monoesters, said phosphorus-containing compound having a hydrocarbon group having 1 to 8 carbon atoms, and (B) a tertiary amine compound having a hydrocarbon group having 6 to 10 carbon atoms as a substituent (see patent document 2).

In addition, it is also proposed that: a lubricating oil composition obtained by blending (a) a tertiary amine, (B) an acid phosphate ester or the like, and (C) a metal sulfonate or the like (see patent document 3); a lubricating oil composition prepared by blending (a) a primary amine, (B) a tertiary amine, (C) a metal sulfonate, etc., and (D) an acid phosphate, etc. (see patent document 4).

The lubricating oil compositions described in these patent documents have a high coefficient of friction between metals as a lubricating oil for a continuously variable transmission.

Disclosure of Invention

Problems to be solved by the invention

However, a lubricating oil for a metal belt type continuously variable transmission is required to have a high intermetallic friction coefficient between elements and pulleys for power transmission, while a low intermetallic friction coefficient is desired between gears and bearings which are components of the continuously variable transmission from the viewpoint of improving efficiency. Conventionally, no research has been conducted on lubricating oils that satisfy the required characteristics between these different parts.

The present invention is intended to provide a lubricating oil composition which can be suitably used as a lubricating oil for transmissions, particularly a lubricating oil for metal belt type continuously variable transmissions, while satisfying different frictional characteristics between different parts under such circumstances.

Means for solving the problems

The present invention relates to a lubricating oil composition shown below, a method for reducing friction in a continuously variable transmission, and a continuously variable transmission filled with the lubricating oil composition.

[1] A lubricating oil composition comprising (A) a base oil, (B) a diamine, (C) an ethanolamide, and (D) a phosphite.

[2] A continuously variable transmission filled with the lubricating oil composition according to [1 ].

[3] A method for controlling friction in a continuously variable transmission, which comprises using the lubricating oil composition according to [1] above.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the invention, different friction characteristics between different parts can be considered. According to a preferred embodiment of the present invention, a lubricating oil composition having a high coefficient of friction between elements and pulleys and a low coefficient of friction between gears and bearings, which are components of a continuously variable transmission, can be provided. The lubricating oil composition of the present invention can be suitably used as a lubricating oil for a continuously variable transmission, particularly a lubricating oil for a continuously variable transmission such as a metal belt.

Drawings

Fig. 1 is a schematic diagram of a metal belt type continuously variable transmission according to an embodiment of the present invention.

Fig. 2 is a schematic perspective view of a metal belt used in a metal belt type continuously variable transmission according to an embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

1. Lubricating oil composition

The lubricating oil composition of the present invention is characterized by comprising at least (A) a base oil, (B) a diamine, (C) an ethanolamide, and (D) a phosphite. Hereinafter, each component will be described in detail.

(A) Base oil

The base oil as the component (a) used in the present invention is not particularly limited, and may be arbitrarily selected and used from mineral oils and synthetic oils. For example, 1 or more selected from mineral oils and synthetic oils are preferably used. Either mineral oil or synthetic oil alone may be used, or mineral oil and synthetic oil may be used in combination. As the mineral oil and the synthetic oil, mineral oils and synthetic oils generally used as base oils for transmissions are preferable.

The kinematic viscosity of the base oil is not particularly limited, and according to one embodiment of the present invention, the kinematic viscosity at 40 ℃ is preferably 5mm²More than s and 35mm²Less than s, more preferably 7mm²More than s and 30mm²(ii) less than s, more preferably 9mm²More than s and 25mm²The ratio of the water to the water is less than s. If the kinematic viscosity at 40 ℃ is in the above range, a low temperature can be securedFluidity at high temperature, and prevent sintering at high temperature.

The kinematic viscosity at 100 ℃ of the base oil is preferably 1mm²More than s and 50mm²Less than s, more preferably 2mm²More than s and 30mm²(ii) less than s, more preferably 3mm²More than s and 20mm²The ratio of the water to the water is less than s. When the kinematic viscosity at 100 ℃ is in the above range, the fluidity at low temperature can be ensured and the seizure at high temperature can be prevented.

The pour point as an index of the low temperature fluidity of the base oil is not particularly limited, and according to one embodiment of the present invention, the pour point is preferably-10 ℃ or lower, more preferably-15 ℃ or lower, and still more preferably-20 ℃ or lower. When the pour point is in the above range, fluidity at low temperature can be ensured.

Further, according to one embodiment of the present invention, it is preferable that the saturated hydrocarbon component in the base oil is 90% by mass or more, the sulfur component is 0.03% by mass or less, and the viscosity index is 100 or more. The viscosity index is more preferably 105 or more, and still more preferably 110 or more.

When the saturated hydrocarbon component is 90% by mass or more, the formation of deteriorated products can be reduced. By setting the sulfur content to 0.03 mass% or less, the production of deteriorated products can be reduced in the same manner. Further, if the viscosity index is 100 or more, abrasion at high temperature can be suppressed. The larger the viscosity index of the base oil is, the more preferable the viscosity index is, the upper limit of the viscosity index is not particularly limited, and the viscosity index is generally 150 or less.

As the mineral oil, for example, there can be preferably mentioned: naphthenic mineral oil, paraffinic mineral oil, natural gas synthetic oil (GTL), and the like. Specifically, light neutral oil, medium neutral oil, heavy neutral oil, bright stock (bright stock), and the like, which are solvent-refined or hydrorefined, can be exemplified.

As the synthetic oil, polybutene or its hydride, poly α -olefin (1-octene oligomer, 1-decene oligomer, etc.), α -olefin copolymer, alkylbenzene, polyol ester, dibasic acid ester, polyoxyalkylene glycol ester, polyoxyalkylene glycol ether, hindered ester, silicon oil, etc. can be preferably cited.

The mineral oil and the synthetic oil may be used in 1 type, or 2 or more types may be used in combination.

In the present specification, the kinematic viscosity and viscosity index at a predetermined temperature are expressed in terms of JISK 2283: 2000 measured values. The pour point of the base oil is the lowest temperature at which the mineral oil-based lubricating oil flows when cooled by the method defined in JIS K2269. The sulfur content is a value measured according to JIS K2541-3.

When 2 or more base oils are used, the above numerical values are those of base oils obtained by mixing them.

The content of the base oil (a) is preferably 60% by mass or more and 99.98% by mass or less, more preferably 70% by mass or more and 99% by mass or less, further preferably 75% by mass or more and 98% by mass or less, and further preferably 80% by mass or more and 98% by mass or less, based on the total amount of the composition. If the amount is within this range, the solubility of the additive can be ensured.

(B) Diamines

The diamine (B) used in the present invention is not particularly limited as long as it has two substituted or unsubstituted amino groups, and is preferably a compound represented by the general formula (I).

[ solution 1]

[ in the formula, R¹And R²Each independently is hydrogen or hydrocarbyl, R³Is a divalent hydrocarbon group.]

By using the compound represented by the general formula (I) as the diamine (B), the intermetallic friction coefficient between the gear and the bearing can be reduced.

R¹Is hydrogen or a hydrocarbyl group.

R¹In the case of a hydrocarbon group, the number of carbon atoms of the hydrocarbon group is preferably 16 or more and 22 or less, more preferably 16 or more and 20 or less, and still more preferably 17 or more and 19 or less. When the number of carbon atoms is in this range, the metal-to-metal friction between the element and the pulley can be effectively increasedCoefficient of friction.

Examples of such a hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, and an aralkyl group. Among these hydrocarbon groups, aliphatic hydrocarbon groups are preferable, and alkenyl groups are particularly preferable. Examples thereof include: hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, oleyl, and the like. Among them, oleyl group is most preferable.

The carbon chain portion may have a straight chain structure or a branched chain structure, and particularly, a carbon chain portion having a straight chain structure is preferable in terms of increasing the intermetallic friction coefficient between the element and the pulley.

R²Is hydrogen or a hydrocarbyl group. At R²In the case of a hydrocarbon group, an alkyl group is preferable. In addition, R²The number of carbon atoms of (2) is preferably 3 or less. Examples of such alkyl groups include methyl, ethyl and propyl, and from the viewpoint of reducing the coefficient of friction between gears and bearings, R is²Preferably propyl.

R³Is a divalent hydrocarbon group, preferably an alkylene group. From the viewpoint of stability, R³Preferably, the carbon number of (b) is about 1 to 5, more preferably about 2 to 5, still more preferably about 2 to 4, and particularly preferably about 3.

The content of the diamine (B) is preferably 0.03 mass% or more and 0.1 mass% or less, more preferably 0.04 mass% or more and 0.09 mass% or less, and further preferably 0.05 mass% or more and 0.08 mass% or less, based on the total amount of the composition. Within this range, the intermetallic friction coefficient between the gear and the bearing can be reduced.

(C) Ethanolamides

The ethanol amide (C) used in the present invention is not particularly limited, and is preferably a compound represented by the general formula (II).

[ solution 2]

[ in the formula, R⁴And R⁵Each independently isHydrogen or a hydrocarbyl group.]

R⁴And R⁵Each independently hydrogen or a hydrocarbyl group. At R⁴And R⁵When each is a hydrocarbon group, the carbon number of the hydrocarbon group is preferably 6 or more and 24 or less, more preferably 8 or more and 20 or less, and further preferably 10 or more and 18 or less. When the carbon number is in this range, a high intermetallic friction coefficient between the element and the pulley can be maintained, and further, chatter vibration resistance can be obtained.

Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an alkadienyl group, a cycloalkyl group, an aryl group, and an aralkyl group.

Examples of the alkyl group include: various hexyl groups such as an n-hexyl group, an isohexyl group, an sec-hexyl group, and a tert-hexyl group (hereinafter, functional groups having a predetermined carbon number, including linear, branched, and isomers thereof, may be abbreviated as various functional groups), various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various undecyl groups, various dodecyl groups, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, various nonadecyl groups, various eicosyl groups, various heneicosyl groups, various docosyl groups, various tricosyl groups, and various tetracosyl groups.

Examples of the alkenyl group include: various hexenyl groups, various heptenyl groups, various octenyl groups, various nonenyl groups, various decenyl groups, various undecenyl groups, various dodecenyl groups, various tridecenyl groups, various tetradecenyl groups, various pentadecenyl groups, various hexadecenyl groups, various heptadecenyl groups, various octadecenyl groups, various nonadecenyl groups, various eicosenyl groups, various heneicosenyl groups, various docosenyl groups, various tricosenyl groups, and various tetracosenyl groups.

Examples of alkadienyl groups include: various hexadienyl groups, various heptadienyl groups, various octadienyl groups, various nonadienyl groups, various decadienyl groups, various undecadienyl groups, various dodecadienyl groups, various tridecadienyl groups, various tetradecadienyl groups, various pentadecadienyl groups, various hexadecadienyl groups, various heptadecadienyl groups, various octadecadienyl groups, various nonadecadienyl groups, various eicosadienyl groups, various heneicosaddienyl groups, various docosadienyl groups, various tricosadienyl groups, various tetracosadienyl groups, and the like.

Examples of the cycloalkyl group include: cyclohexyl, various methylcyclohexyl, various ethylcyclohexyl, various dimethylcyclohexyl.

Examples of the aryl group include: phenyl, various methylphenyl, various ethylphenyl, various dimethylphenyl, various propylphenyl, various trimethylphenyl, various butylphenyl, various naphthyl and the like.

Examples of the aralkyl group include: benzyl, phenethyl, various phenylpropyl, various phenylbutyl, various methylbenzyl, various ethylbenzyl, various propylbenzyl, various butylbenzyl, various hexylbenzyl, and the like.

In the ethanolamide (C), for R in the above general formula (II)⁴And R⁵Preferably, all R's are⁴And R⁵The content of the hydrocarbon group having 12 carbon atoms in the resin composition is 30 to 75 mass%, and the content of the hydrocarbon group having 14 carbon atoms is 5 to 40 mass%. By using such an amide compound, a high intermetallic friction coefficient and excellent anti-shudder properties can be obtained. Here, "all R⁴And R⁵"means that R in the ethanol amide represented by the general formula (II)⁴And R⁵Total amount (total amount) of (c). Thus, "all R⁴And R⁵The "content of C12 hydrocarbon group" in (A) means that R in the ethanol amide represented by the general formula (II)⁴And R⁵R is defined as the total amount (total amount) of⁴、R⁵A content of a hydrocarbon group having 12 carbon atoms contained in at least one of the above. For example, when two or more types of ethanol amides represented by the general formula (II) are used, R contained in each amide compound is converted to⁴And R⁵The total amount (total amount) obtained by the combination becomes "all R⁴And R⁵", as the R⁴、R⁵The content of the C12 hydrocarbon group contained in at least one of the aboveIs "all R⁴And R⁵The content of hydrocarbon groups having 12 carbon atoms in (c) ". For "all R⁴And R⁵The same applies to the content of the hydrocarbon group having 14 carbon atoms in (A). In addition, as the glycolamide of the present invention, a reaction product of an amine and glycolic acid may also be used.

All R from the standpoint of obtaining a high intermetallic coefficient of friction and excellent shudder resistance⁴And R⁵The content of the hydrocarbon group having 12 carbon atoms in (b) is preferably 33 mass% or more, more preferably 35 mass% or more, and still more preferably 40 mass% or more. The upper limit is preferably 70% by mass or less, more preferably 68% by mass or less, and still more preferably 65% by mass or less. In addition, all R⁴And R⁵The content of the hydrocarbon group having 12 carbon atoms in (b) is preferably 33 mass% or more and 70 mass% or less, more preferably 35 mass% or more and 68 mass% or less, and still more preferably 40 mass% or more and 65 mass% or less. All R⁴And R⁵The content of the hydrocarbon group having 14 carbon atoms in (b) is preferably 7% by mass or more, more preferably 10% by mass or more, and still more preferably 13% by mass or more. The upper limit is preferably 35% by mass or less, more preferably 30% by mass or less, and still more preferably 25% by mass or less. In addition, all R⁴And R⁵The content of the hydrocarbon group having 14 carbon atoms in (b) is preferably 7% by mass or more and 35% by mass or less, more preferably 10% by mass or more and 30% by mass or less, and still more preferably 13% by mass or more and 25% by mass or less.

The content of the ethanolamide (C) is preferably 0.1% by mass or more and 3% by mass or less, more preferably 0.2% by mass or more and 2% by mass or less, and further preferably 0.3% by mass or more and 1% by mass or less, based on the total amount of the composition. Within this range, a high intermetallic friction coefficient between the element and the pulley can be maintained, and further, chatter vibration resistance can be obtained.

(D) Phosphite esters

Specific examples of the phosphite (D) include compounds represented by the following formula (III).

(R⁶O)_aP(OH)_3-a(III)

[ in the formula, R⁶Is a hydrocarbon group having 2 to 24 carbon atoms, and a is an integer of 1 to 3. In case a is 2 or 3, R⁶May be the same or different from each other.]

In the formula (III), as R⁶Examples of the hydrocarbon group having 2 to 24 carbon atoms include: an alkyl group having 2 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, an aralkyl group having 7 to 24 carbon atoms, and the like.

The alkyl group and the alkenyl group may be any of linear, branched, and cyclic, and examples thereof include: ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various pentyl groups, various hexyl groups, various octyl groups, various decyl groups, various dodecyl groups, various tetradecyl groups, various hexadecyl groups, various octadecyl groups, various nonadecyl groups, various eicosyl groups, various docosyl groups, various tricosyl groups, various tetracosyl groups, cyclopentyl groups, cyclohexyl groups, allyl groups, propenyl groups, various butenyl groups, various hexenyl groups, various octenyl groups, various decenyl groups, various dodecenyl groups, various tetradecenyl groups, various hexadecenyl groups, various octadecenyl groups, various nonadecenyl groups, various eicosenyl groups, various heneicosenyl groups, various docosenyl groups, various tricosenyl groups, various tetracosenyl groups, cyclopentenyl groups, cyclohexenyl groups, and the like. The term "various" as used herein means a group including a straight chain and all branched chains as structural isomers thereof, and the same applies hereinafter.

Examples of the aryl group having 6 to 24 carbon atoms include: examples of the aralkyl group having 7 or more and 24 or less carbon atoms include a benzyl group, a phenethyl group, a naphthylmethyl group, a methylbenzyl group, a methylphenylethyl group, a methylnaphthylmethyl group, and the like.

Preferred phosphites (D) are those of the formula (III) in which a is 1 or 2 and R is⁶Is fat with carbon number of 2-10Group of hydrocarbyl compounds, more preferably a is 1 or 2 and R⁶The aliphatic hydrocarbon group has 2 to 8 carbon atoms, and the aliphatic hydrocarbon group is more preferably an alkyl group.

Examples of the phosphite ester (D) include ethyl hydrogen phosphite, n-propyl hydrogen phosphite, n-butyl hydrogen phosphite, and 2-ethylhexyl hydrogen phosphite, and among these, 2-ethylhexyl hydrogen phosphite is preferable.

The phosphite (D) may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

The content of the phosphite ester (D) is preferably 0.05% by mass or more and 2% by mass or less, more preferably 0.1% by mass or more and 1.8% by mass or less, and further preferably 0.8% by mass or more and 1.4% by mass or less, based on the total amount of the composition. Within this range, the intermetallic friction coefficient between the element and the pulley can be increased.

(E) Polymethacrylate

In the present invention, Polymethacrylate (PMA) may be contained.

As the polymethacrylate used in the present invention, polyalkylmethacrylate and the like are preferable. Polymethacrylates are included for the purpose of suitably increasing the viscosity index. The dispersion type is either a dispersion type or a non-dispersion type, and the non-dispersion type is preferable. The polymer may be linear or branched. Further, the polymer may have a specific structure such as a comb polymer having a structure in which a large number of trifurcated branch points extending from a high molecular weight side chain are present in the main chain.

In the present invention, the polymethacrylate may contain a polymethacrylate having a monovalent functional group containing an oxygen atom in the molecule, which has a structural unit represented by the following general formula (IV) (also referred to as "multipoint adsorption-type polymethacrylate" in the present specification).

[ solution 3]

In the general formula (IV), R^aX represents a divalent aliphatic hydrocarbon group having 24 or more and 40 or less carbon atoms¹Represents a monovalent functional group comprising an oxygen atom. If R is^aThe number of carbon atoms of (2) is preferably 24 or more from the viewpoint of viscosity index. In addition, a carbon number of 40 or less is preferable from the viewpoint of shear stability.

As R^aThe divalent aliphatic hydrocarbon group having 24 or more and 40 or less carbon atoms includes alkylene groups, alkenylene groups, and the like, and alkylene groups are preferable from the viewpoint of easily achieving both a high viscosity index and high shear stability. The polymer may be any of linear, branched and cyclic, and is preferably a linear or branched group from the viewpoint of easily achieving a high viscosity index and high shear stability. From the same viewpoint, the carbon number is preferably 28 or more and 40 or less, and more preferably 30 or more and 40 or less.

For example, the alkylene group having 24 or more and 40 or less carbon atoms includes: various tetracosylene groups such as n-tetracosylene group, isotetracosylene group and isomers thereof (hereinafter, functional groups having a predetermined carbon number, including linear, branched and isomers thereof, may be abbreviated as various functional groups), various pentacosylene groups, various hexacosylene groups, various heptacosylene groups, various octacosylene groups, various nonacosylene groups, various triacontylene groups, various hentriacontylene groups, various dotriacontaylene groups, various tritriacontylene groups, various tetratriacontylene groups, various tripentaerythritol groups, various pentacontylene groups, various hexacyclobutene groups, various heptadecamethylene groups, various octatriacontylene groups, various nonadecanonadecamethylene groups, and various forty-alkyl-ene groups.

In the general formula (IV), X¹Is a monovalent functional group containing oxygen. If the monovalent functional group contains oxygen, high viscosity index and high shear stability can be obtained. From the viewpoint of easily achieving a high viscosity index and high shear stability, preferable examples thereof include: hydroxyl, alkoxy, formyl, carboxyl, ester, nitro, amide, carbamate, sulfo and the like, preferably hydroxyl and alkoxy, and more preferably hydroxyl. Here, as the alkoxy group, a group,the alkoxy group is preferably an alkoxy group containing an alkyl group having 1 to 30 carbon atoms, and the alkyl group may be either linear or branched.

The multi-site adsorption-type polymethacrylate may contain another structural unit represented by the following general formula (V) as long as it has the structural unit represented by the above general formula (IV).

[ solution 4]

In the general formula (V), R^bX represents a divalent aliphatic hydrocarbon group having 1 to 40 carbon atoms²Represents a monovalent functional group.

As R^bA divalent aliphatic hydrocarbon group having 1 to 40 carbon atoms, except as R^aExamples of the divalent aliphatic hydrocarbon group having 24 or more and 40 or less carbon atoms include divalent aliphatic hydrocarbon groups having 1 or more and 23 or less carbon atoms. The divalent aliphatic hydrocarbon group having 1 to 23 carbon atoms is preferably an alkylene group or an alkenylene group, and more preferably an alkylene group, from the viewpoint of easily achieving a high viscosity index and high shear stability. The alkylene group may be linear or branched, and the number of carbon atoms is more preferably 1 to 30.

As X²Examples of the monovalent functional group include aryl groups such as phenyl, benzyl, tolyl and xylyl, heterocyclic groups such as furyl, thienyl, pyridyl and carbazolyl, organic groups containing a hetero atom represented by the following general formulae (VI) to (VII), and R^bWhen the number of carbon atoms of (2) is 1 to 23, there may be mentioned, in addition to the above monovalent functional groups, the above X¹And a functional group containing an oxygen atom.

[ solution 5]

——Ｓ—R^c(VII)

In the general formulae (VI) and (VII), R^cEach of which isIndependently represents a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 30 carbon atoms. The monovalent aliphatic hydrocarbon group is preferably an alkyl group, an alkenyl group, or the like, and more preferably an alkyl group, from the viewpoint of easily achieving a high viscosity index and high shear stability. The monovalent aliphatic hydrocarbon group may be linear or branched.

The ratio of the structural unit represented by the above general formula (IV) is not particularly limited as long as the structural unit has the structural unit, and from the viewpoint of easily achieving a high viscosity index and high shear stability, the copolymerization ratio of the structural unit represented by the above general formula (IV) to a structural unit other than the structural unit represented by the above general formula (IV), such as the above-mentioned other structural unit (for example, the structural unit represented by the above general formula (V)), is preferably 10: 90 to 90: 10, more preferably 20: 80 to 80: 20, and further preferably 30: 70 to 70: 30.

The mass average molecular weight of the polymethacrylate used in the present invention is preferably 5000 or more, more preferably 15000 or more, further preferably 20000 or more, and particularly preferably 25000 or more. The upper limit is preferably 100000 or less, more preferably 80000 or less, still more preferably 70000 or less, and particularly preferably 55000 or less. The mass average molecular weight of the polymethacrylate is preferably 5000 or more and 100000 or less, more preferably 15000 or more and 80000 or less, still more preferably 20000 or more and 70000 or less, and particularly preferably 25000 or more and 55000 or less. By setting the mass average molecular weight of the polymethacrylate to the above range, it is possible to easily achieve both a high viscosity index and high shear stability.

Here, the mass average molecular weight can be measured by a Gel Permeation Chromatography (GPC) method and determined from a calibration curve prepared using polystyrene. For example, the mass average molecular weight of each polymer can be calculated as a polystyrene equivalent by the following GPC method.

< GPC measurement apparatus >

Column: TOSO GMHHR-H (S) HT

The detector: liquid chromatography RI detector WATERS 150C

< measurement conditions, etc. >

Solvent: 1, 2, 4-trichlorobenzene

Measurement temperature: 145 deg.C

Flow rate: 1.0 ml/min

Sample concentration: 2.2 mg/ml

Injection amount: 160 microliter

Standard curve: universal Calibration (Universal Calibration)

Analysis program: HT-GPC (Ver, 1.0)

The content of the polymethacrylate is usually 1% by mass or more, preferably 3% by mass or more, and more preferably 4% by mass or more, and the upper limit is usually 15% by mass or less, preferably 13% by mass or less, and more preferably 11% by mass or less, based on the total amount of the composition. When the content of the polymethacrylate is in the above range, the effect of adding the polymethacrylate can be sufficiently obtained, and both high viscosity index and high shear stability can be easily achieved.

(F) Ashless friction modifier

The lubricating oil composition of the present invention may contain an ashless friction modifier, if necessary. By containing the ashless friction modifier, the intermetallic friction coefficient between the gear and the bearing can be further reduced in some cases.

Examples of the ashless friction modifier include ester-based ashless friction modifiers and amine-based ashless friction modifiers. As the ashless friction modifier, 1 kind may be used alone, or 2 or more kinds may be used in combination.

Examples of the ester-based ashless friction modifier include esters of fatty acids and aliphatic alcohols. The fatty acid includes an aliphatic monocarboxylic acid having a linear or branched hydrocarbon group having 6 to 30 carbon atoms, and the hydrocarbon group has preferably 8 to 24 carbon atoms, and more preferably 10 to 20 carbon atoms. The term "hydrocarbon group" as used herein means a hydrocarbon moiety other than the carboxyl group of a fatty acid.

As the aliphatic alcohol, an aliphatic polyol is used. The ester of the fatty acid and the fatty alcohol may be a partial ester in which only a part of the alcohol is esterified, or a complete ester in which all the alcohol is esterified, and a partial ester is usually used.

Examples of the linear or branched hydrocarbon group having 6 to 30 carbon atoms include: alkyl groups such as hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl, and triacontyl; alkenyl groups such as hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, eicosenyl, heneicosenyl, docosenyl, tricosenyl, tetracosenyl, pentacosenyl, hexacosenyl, heptacosenyl, octacosenyl, nonacosenyl and triacontenyl; a hydrocarbon group having 2 or more double bonds, and the like. The alkyl group, alkenyl group, and hydrocarbon group having 2 or more double bonds include all conceivable straight-chain structures and branched-chain structures, and the positions of the double bonds in the alkenyl group and the hydrocarbon group having 2 or more double bonds are arbitrary.

Specific examples of the fatty acid include: saturated fatty acids such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and lignoceric acid, and unsaturated fatty acids such as myristoleic acid, palmitoleic acid, oleic acid and linolenic acid, are preferred, and oleic acid is more preferred.

The aliphatic polyhydric alcohol is an alcohol having a valence of 2 to 6, and examples thereof include ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and the like, and glycerin is preferred.

That is, as the ester-based ashless friction modifier, an ester of glycerin and the above-mentioned aliphatic monocarboxylic acid is preferable. The ester may be a complete ester, preferably a partial ester, and among them, more preferably a partial ester obtained by the reaction of glycerin with the above-mentioned unsaturated fatty acid. Specifically, there may be mentioned: monoesters such as glyceryl monomyristate, glyceryl monopalmitate and glyceryl monooleate; diesters such as dimyristolein, dipalmitolein and dioleolein.

The amine-based ashless friction modifier may be an aliphatic amine compound having a linear or branched hydrocarbon group having 6 to 30 carbon atoms. The hydrocarbon group of the amine compound preferably has 8 to 24 carbon atoms, more preferably 10 to 20 carbon atoms. The hydrocarbon group having 6 to 30 carbon atoms is preferably the one exemplified as the hydrocarbon group of the fatty acid.

Examples of the aliphatic amine compound include aliphatic monoamines or alkylene oxide adducts thereof, alkanolamines, aliphatic polyamines, imidazoline compounds, and the like. Specifically, there may be mentioned: aliphatic amine compounds such as laurylamine, lauryldiethylamine, lauryldiethanolamine, lauryldipropanolamine, palmitylamine, stearylamine, stearyltetraethylenepentamine, oleylamine, oleylpropylenediamine, oleyldiethanolamine, dimethyloctadecylamine and N-hydroxyethyl oleylimidazoline; amine alkylene oxide adducts of these aliphatic amine compounds, such as N, N-polyoxyalkylene-N-alkyl (or alkenyl) (having 6 to 28 carbon atoms).

As the ashless friction modifier, an amine-based ashless friction modifier is preferable, and among them, as described above, stearylamine, stearyltetraethylenepentamine, oleylamine, oleylpropylenediamine, oleyldiethanolamine, and N-hydroxyethyl oleylimidazoline are more preferable, and oleylamine, oleylpropylenediamine, and oleyldiethanolamine are particularly more preferable.

The content of the ashless friction modifier is preferably 0.2 to 1.8% by mass, more preferably 0.2 to 1.7% by mass, and still more preferably 0.2 to 1.5% by mass, based on the total amount of the composition.

(G) Other additives

In the lubricating oil composition of the present invention, various additives may be blended in addition to the above components within a range not impairing the object and effect of the present invention. For example, one or more selected from viscosity index improvers, pour point depressants, ashless detergent dispersants, metal-based detergents, antioxidants, rust inhibitors, metal deactivators, anti-wear agents, antifoaming agents, coefficient of friction modifiers and basic compounds may be appropriately compounded.

Examples of the viscosity index improver include: non-dispersed polymethacrylates, olefin copolymers (e.g., ethylene-propylene copolymers), dispersed olefin copolymers, styrene copolymers (e.g., styrene-diene copolymers, styrene-isoprene copolymers), and the like.

The mass average molecular weight (Mw) of these viscosity index improvers is usually 500 to 1000000, preferably 5000 to 800000, more preferably 10000 to 600000, and further preferably 15000 to 50000, from the viewpoint of satisfying both the temperature-viscosity characteristics and the shear stability, and is appropriately set according to the type of polymer.

Examples of pour point depressants include: ethylene-vinyl acetate copolymers, condensates of chlorinated paraffins and naphthalene, condensates of chlorinated paraffins and phenols, polymethacrylates, polyalkylstyrenes, etc., with polymethacrylates being preferably used.

The mass average molecular weight (Mw) of these pour point depressants is usually 50000 or more and 150000 or less.

Examples of ashless cleaning dispersants include: and imides such as succinimides and boron-containing succinimides, benzyl amines, boron-containing benzyl amines, and divalent carboxamides represented by succinic acid. Among these, succinimides are preferable.

Examples of the succinimide compound include: mono-or bis-imides of succinic acid having a polyalkenyl group such as a polybutenyl group having a number average molecular weight of 300 to 4000 and a polyethylene polyamine such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or pentaethylenehexamine, or boric acid-modified products thereof; mannich reactants of phenols having a polyalkenyl group with formaldehyde and polyethylene polyamine, and the like.

Examples of the metal-based detergent include: neutral metal sulfonates, neutral metal phenates, neutral metal salicylates, neutral metal phosphonates, basic metal sulfonates, basic metal phenates, basic metal salicylates, basic metal phosphonates, overbased metal sulfonates, overbased metal phenates, overbased metal salicylates, and overbased metal phosphonates, and the like.

The antioxidant may be selected from any antioxidants used as antioxidants for lubricating oils, and examples thereof include: amine antioxidants, phenol antioxidants, molybdenum antioxidants, sulfur antioxidants, phosphorus antioxidants, and the like.

These antioxidants may be used alone, or 2 or more of them may be used in combination.

Examples of the amine-based antioxidant include diphenylamine-based antioxidants such as diphenylamine and alkylated diphenylamine having an alkyl group having 3 to 20 carbon atoms, naphthylamine-based antioxidants such as α -naphthylamine, phenyl- α -naphthylamine, and substituted phenyl- α -naphthylamine having an alkyl group having 3 to 20 carbon atoms, and the like.

Examples of the phenolic antioxidant include: monophenol antioxidants such as 2, 6-di-t-butylphenol, 2, 6-di-t-butyl-4-methylphenol, 2, 6-di-t-butyl-4-ethylphenol, isooctyl 3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, and octadecyl 3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate; diphenol-based antioxidants such as 4, 4 '-methylenebis (2, 6-di-tert-butylphenol) and 2, 2' -methylenebis (4-ethyl-6-tert-butylphenol); a hindered phenol-based antioxidant; and so on.

Examples of the molybdenum-based antioxidant include: and molybdenum amine complexes obtained by reacting molybdenum trioxide and/or molybdic acid with amine compounds.

Examples of the sulfur-based antioxidant include dilauryl 3, 3' -thiodipropionate.

Examples of the rust inhibitor include: fatty acids, alkenyl succinic acid half esters, fatty acid soaps, alkyl sulfonates, polyol fatty acid esters, fatty acid amines, oxidized paraffins, alkyl polyoxyethylene ethers, and the like.

Examples of the metal deactivator include: benzotriazole compounds, methylbenzotriazole compounds, thiadiazole compounds, imidazole compounds, pyrimidine compounds, and the like.

Examples of the anti-wear agent include: sulfur compounds such as sulfides, sulfoxides, sulfones, and thiophosphites; halogen-based compounds such as chlorinated hydrocarbons; and organometallic compounds such as zinc dithiocarbamate (ZnDTC), molybdenum oxysulfide organic dithiophosphate (MoDTP), molybdenum oxysulfide dithiocarbamate (MoDTC), and tricresyl phosphate.

The defoaming agent is preferably a polymer silicone defoaming agent, and by including the polymer silicone defoaming agent, defoaming performance is effectively exhibited and riding comfort is improved. The high-molecular silicone defoaming agent is particularly preferably a fluorine-containing organopolysiloxane such as organopolysiloxane and trifluoropropylmethylsilicone.

Examples of the friction coefficient adjuster include: higher fatty acids such as oleic acid, stearic acid, and palmitic acid; fatty alcohols such as lauryl alcohol, oleyl alcohol and cetyl alcohol; esters such as ethyl oleate, sorbitan monostearate, and glycerol monooleate; amine compounds such as hexadecylamine, octadecylamine and dimethyloctadecylamine.

Examples of the basic compound include: ammonia; (cyclo) alkylamines such as methylamine, dimethylamine, ethylamine, diethylamine, (iso) propylamine, di (iso) propylamine, butylamine, dibutylamine, hexylamine, cyclohexylamine, octylamine, 2-ethylhexylamine, and isononylamine; polyalkylene polyamines such as ethylenediamine, propylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine; cyclic amines such as pyridine and piperazine; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, N-cyclohexyldiethanolamine, N, N, N ', N' -tetrakis (hydroxyethyl) ethylenediamine, and N, N, N ', N' -tetrakis (2-hydroxypropyl) ethylenediamine.

The content of each additive may be appropriately adjusted within a range not impairing the effects of the present invention, and is usually 0.001% by mass or more and 10% by mass or less, preferably 0.005% by mass or more and 8% by mass or less, and more preferably 0.01% by mass or more and 5% by mass or less, based on the total amount of the composition.

The total content of these additives is preferably 0% by mass or more and 35% by mass or less, more preferably 0% by mass or more and 25% by mass or less, further preferably 0% by mass or more and 20% by mass or less, further preferably 0% by mass or more and 15% by mass or less, and particularly preferably 0% by mass or more and 10% by mass or less, based on the total amount of the composition.

In one embodiment of the lubricating oil composition of the present invention, the fatty amide is preferably not substantially contained, and the content of the fatty amide is preferably less than 0.04% by mass, more preferably less than 0.03% by mass, and still more preferably less than 0.02% by mass, based on the total amount of the composition.

By containing substantially no fatty amide, the intermetallic friction coefficient between the element and the pulley can be further increased.

The kinematic viscosity at 40 ℃ of the lubricating oil composition of the present invention is preferably 5mm from the viewpoint of ensuring fluidity at low temperatures and seizure resistance by evaporation at high temperatures²More than s and 35mm²Less than s, more preferably 7mm²More than s and 30mm²(ii) less than s, more preferably 9mm²More than s and 25mm²The ratio of the water to the water is less than s.

The kinematic viscosity at 100 ℃ of the lubricating oil composition for a shock absorber of the present invention is preferably 2mm from the viewpoint of ensuring fluidity at low temperature²More than s and 20mm²Less than s, more preferably 2.5mm²15mm of more than s²A value of not more than s, more preferably 2.8mm²More than s and 10mm²Less than s, particularly preferably 5mm²6mm of more than s²The ratio of the water to the water is less than s.

The viscosity index of the lubricating oil composition of the present invention is preferably 100 or more, more preferably 120 or more, and even more preferably 150 or more, from the viewpoint of ensuring fluidity at low temperatures and seizure resistance by evaporation at high temperatures. The larger the viscosity index is, the more preferable the viscosity index is, the upper limit is not particularly limited, and the viscosity index is usually 250 or less.

In the lubricating oil composition of the present invention, the amount of phosphorus not bonded to a sulfur atom contained in the composition is preferably 10000 ppm by mass or less, more preferably 1000 ppm by mass or less, and still more preferably 700 ppm by mass or less, based on the total amount of the lubricating oil composition, from the viewpoint of improving the intermetallic friction coefficient between the element and the pulley.

In the lubricating oil composition of the present invention, the amount of calcium contained in the composition is preferably 10000 ppm by mass or less, more preferably 1000 ppm by mass or less, and still more preferably 700 ppm by mass or less, based on the total amount of the lubricating oil composition, from the viewpoint of improving the intermetallic friction coefficient between the element and the pulley.

In the lubricating oil composition of the present invention, the amount of sulfur contained in the composition is preferably 10000 ppm by mass or less, more preferably 800 ppm by mass or less, and still more preferably 500 ppm by mass or less, based on the total amount of the lubricating oil composition, from the viewpoint of improving the intermetallic friction coefficient between the element and the pulley.

In the lubricating oil composition of the present invention, the amount of nitrogen contained in the composition is preferably 10000 ppm by mass or less, more preferably 800 ppm by mass or less, and still more preferably 500 ppm by mass or less, based on the total amount of the lubricating oil composition, from the viewpoint of improving the intermetallic friction coefficient between the element and the pulley.

The lubricating oil composition of the present invention can be produced by blending various components in a base oil and, if necessary, uniformly dispersing the components by stirring or the like. In one embodiment of the present invention, the base oil is heated to 50 ℃ and then the various components are mixed and stirred, whereby the various components can be dispersed more uniformly in the base oil.

The lubricating oil composition of the present invention is suitable as a lubricating oil for transmissions, particularly as a lubricating oil for continuously variable transmissions. In particular, the lubricating oil composition of the present invention is suitable as a lubricating oil for a Belt-type continuously variable transmission such as a Push Belt (Push Belt) type or a chain type, and is particularly suitable as a lubricating oil composition for a metal Belt-type continuously variable transmission.

According to a preferred embodiment of the present invention, by using the lubricating oil composition of the present invention as a lubricating oil composition for a metal belt type continuously variable transmission, the intermetallic friction coefficient between elements and pulleys can be increased, and the intermetallic friction coefficient can be controlled to a low level between gears and bearings that are components of the continuously variable transmission, so that power transmission between elements and pulleys can be efficiently performed, friction between gears and bearings can be suppressed, efficiency can be improved, and fuel economy can be improved.

2. Continuously variable transmission

The continuously variable transmission of the present invention is not particularly limited as long as it is filled with the lubricating oil composition described in the above "1. lubricating oil composition", and can more effectively exhibit the lubricating performance of the lubricating oil composition, and therefore, a push-type belt-type or chain-type continuously variable transmission is preferable, and a metal belt-type continuously variable transmission is particularly preferable.

Fig. 1 is a schematic diagram of a metal belt type continuously variable transmission according to an embodiment of the present invention. As shown in fig. 1, a metal belt 1 is stretched over two pulleys, a pulley (input side) 2 connected to an input shaft connected to an engine clutch and a pulley (output side) 3 connected to an output shaft on the side of a final gear 7 to constitute a transmission mechanism of a metal belt type continuously variable transmission 10, and although not shown, a lubricating oil composition is filled in the transmission mechanism.

The pulleys 2 and 3 that rotate are each configured by combining 2 conical disks, and power is transmitted by friction between facing conical slopes and the side surfaces of the belt 1. The speed change is performed steplessly by changing the effective radius of the metal belt 1 by relatively changing the groove widths of the input-side pulley 2 and the output-side pulley 3. Although not shown, bearings are incorporated in the bearing portions of various gears such as the side gear 4, the reverse gear 5, the output gear 6, and the final gear 7.

Fig. 2 is a schematic perspective view of a metal belt for a metal belt type continuously variable transmission according to an embodiment of the present invention. As shown in fig. 2, the metal belt 1 is assembled from several hundred thin steel members 8 having V-angles and 2 sets of thin steel laminated rings 9 sandwiching them from both sides. The metal strip 1 is moved by pushing the elements 8 in front of it by means of one element 8.

According to a preferred embodiment of the present invention, the continuously variable transmission of the present invention is excellent in fuel economy because the lubricating oil composition filled in the lubricating oil composition has a high coefficient of friction between metals between elements and pulleys, enabling power transmission, and has a low coefficient of friction between metals between gears and bearings, which are components of the continuously variable transmission, enabling efficient operation.

The continuously variable transmission of the present invention can be used for both four-wheel vehicles and two-wheel vehicles, and is particularly suitable as a continuously variable transmission for four-wheel vehicles.

3. Method of controlling friction in continuously variable transmission

The method of controlling friction in a continuously variable transmission of the present invention comprises using the lubricating oil composition described in the above "1. lubricating oil composition" as a lubricating oil composition for a continuously variable transmission.

According to a preferred aspect of the present invention, by using the lubricating oil composition described in the above "1. lubricating oil composition" as a lubricating oil composition for a continuously variable transmission, as described above, it is possible to appropriately control different metal-to-metal friction at different portions of the continuously variable transmission, and it is possible to contribute to an improvement in fuel economy.

The friction control method of the present invention can control the metal-to-metal friction in any of the continuously variable transmissions for four-wheeled vehicles and two-wheeled vehicles, and the metal-to-metal friction control effect of the continuously variable transmission for four-wheeled vehicles is particularly excellent.