JP2019038961A - Lubricating oil composition for manual transmissions - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating oil composition for a manual transmission which has improved fuel efficiency while satisfying characteristics such as seizure resistance and wear resistance required for a manual transmission oil. (A) API group II base oil, group III base oil, group IV base oil, group V base oil, or a mixed base oil thereof, having a kinematic viscosity at 100 ° C. of 3.0 to 5. The composition of the lubricating oil base oil of 0.0 mm2 / s, (B) calcium-based cleaning agent, 0.05 to 0.10% by mass of calcium content based on the total amount of the composition, and (C) magnesium-based cleaning agent. It contains 0.03 to 0.07% by mass of magnesium based on the total amount of the substance, has a kinematic viscosity at 25 ° C. of 65 mm2 / s or less, has a viscosity index of 150 or more, and satisfies the following formula (1). Lubricating oil composition for manual transmission. 1.0 ≤ Ca / Mg ≤ 2.0 (1) (In the formula, Ca is the calcium content in the composition and Mg is the magnesium content in the composition.) [Selection diagram] None

Description

  The present invention relates to a lubricating oil composition for a manual transmission, and more particularly to a lubricating oil composition for a manual transmission that is excellent in energy saving and is mounted on a vehicle such as an automobile.

  As one of energy saving means in a drive system such as a transmission, there is a reduction in viscosity of the lubricating oil. For example, a transmission has a gear bearing mechanism, and by reducing the viscosity of the lubricating oil used in the transmission, the stirring resistance and drag torque due to the viscous resistance of the lubricating oil are reduced, and the power transmission efficiency As a result, it is considered that fuel efficiency can be improved.

  However, when the viscosity of the lubricating oil used in these gear devices is lowered, it becomes difficult to maintain the oil film thickness on the lubrication surface, and therefore seizure resistance (load bearing capacity) and wear resistance tend to decrease. .

Japanese Patent Laid-Open No. 2006-176015 JP 2010-195894 A

  An object of the present invention is to provide a lubricating oil composition for a manual transmission with improved fuel economy while satisfying characteristics such as seizure resistance and wear resistance required for the manual transmission oil.

One embodiment of the present invention is (A) an API Group II base oil, a Group III base oil, a Group IV base oil, or a Group V base oil, or a mixed base oil thereof, having a kinematic viscosity at 100 ° C. A lubricating base oil of 3.0 to 5.0 mm ² / s, 0.05 to 0.10% by mass of (B) calcium-based detergent as a calcium amount based on the total amount of the composition, and (C) magnesium System detergent containing 0.03-0.07 mass% as magnesium amount on the basis of the total amount of the composition, the kinematic viscosity at 25 ° C. of the composition is 65 mm ² / s or less, and the viscosity index of the composition is The lubricating oil composition for manual transmissions is 150 or more and satisfies the following formula (1).
1.0 ≦ Ca / Mg ≦ 2.0 (1)
(In formula (1), Ca is the calcium content (unit: mass%) in the composition, and Mg is the magnesium content (unit: mass%) in the composition.)

  ADVANTAGE OF THE INVENTION According to this invention, the lubricating oil composition for manual transmissions which improved the fuel-saving property can be provided, satisfying characteristics, such as the seizure resistance and abrasion resistance which are calculated | required by manual transmission oil.

  Hereinafter, the present invention will be described in detail. In this specification, unless otherwise specified, the notation “A to B” for the numerical values A and B means “A or more and B or less”. In this notation, when a unit is attached to only the numerical value B, the unit is also applied to the numerical value A. Further, the terms “or” and “or” mean logical sums unless otherwise specified.

<(A) Lubricating base oil>
As the lubricating base oil in the lubricating oil composition for manual transmission of the present invention (hereinafter sometimes referred to as “manual transmission oil”, “lubricating oil composition” or simply “composition”), the API classification group is used. II base oil, group III base oil, group IV base oil, group V base oil, or a mixed base oil thereof, and a lubricating oil having a kinematic viscosity at 100 ° C. of 3.0 to 5.0 mm ² / s A base oil can be used without particular limitation. API group II base oil is a mineral oil base oil having a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 80 or more and less than 120. The API Group III base oil is a mineral base oil having a sulfur content of 0.03% by mass or more, a saturation content of 90% by mass or more, and a viscosity index of 120 or more. API Group IV base oil is a polyalphaolefin base oil. API Group V base oil is an ester base oil.

  As mineral base oil, solvent degreasing, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrodewaxing of lubricating oil fractions obtained by atmospheric and vacuum distillation of crude oil And mineral oil base oils such as paraffinic and naphthenic oils obtained by appropriately combining one or more purification means such as sulfuric acid washing and clay treatment. API Group II base oils and Group III base oils are typically produced via a hydrocracking process. In addition, wax isomerized base oil, base oil produced by a method of isomerizing GTL WAX (gas-liquid wax), and the like can also be used.

  Examples of API Group IV base oils include ethylene-propylene copolymers, polybutenes, 1-octene oligomers, 1-decene oligomers, and hydrides thereof.

  Examples of API Group V base oils include monoesters (eg, butyl stearate, octyl laurate); diesters (eg, ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sepa). Polyesters (such as trimellitic acid esters); polyol esters (such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate), etc. Can do.

  The lubricating base oil may consist of one base oil or a mixed base oil containing two or more base oils. In the mixed base oil containing two or more kinds of base oils, the API classification of those base oils may be the same or different from each other. However, the content of the API group V base oil is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, based on the total amount of the lubricant base oil, and may be 0 to 10% by mass in one embodiment. . When the content of the ester base oil is not more than the above upper limit value, the oxidation stability of the lubricating oil composition can be improved.

The kinematic viscosity of the lubricating base oil at 100 ° C. is 3.0 to 5.0 mm ² / s, preferably 3.1 to 5.0 mm ² / s. Kinematic viscosity at the 100 ° C. may be in the embodiment of 4.1~5.0mm ² / s, other single in one embodiment at 4.1~4.6mm ² / s. When the kinematic viscosity at 100 ° C. of the lubricating base oil is equal to or less than the above upper limit value, fuel economy can be improved. When the kinematic viscosity at 100 ° C. of the lubricating base oil is not less than the above lower limit value, it is possible to improve the wear resistance and fatigue life. In the present specification, “kinematic viscosity at 100 ° C.” means a kinematic viscosity at 100 ° C. as defined in ASTM D-445.

The kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 40 mm ² / s or less, more preferably 35 mm ² / s or less, and even more preferably 30 mm ² / s or less. On the other hand, the kinematic viscosity at 40 ° C. is preferably 10 mm ² / s or more, and in one embodiment, may be 18 mm ² / s or more. When the kinematic viscosity at 40 ° C. of the lubricating base oil exceeds 40 mm ² / s, there is a risk that sufficient fuel saving performance may not be obtained. When the lubricating base oil is less than 10 mm ² / s, an oil film is formed at the lubricating location. There is a possibility that it becomes insufficient and the lubricity is poor. In the present specification, “kinematic viscosity at 40 ° C.” means the kinematic viscosity at 40 ° C. as defined in ASTM D-445.

  The viscosity index of the lubricating base oil is preferably 100 or more, more preferably 105 or more. In one embodiment, the viscosity index may be 110 or more, 120 or more, or 125 or more. . When the viscosity index of the lubricating base oil is less than 100, not only the viscosity-temperature characteristics and thermal / oxidative stability of the lubricating oil composition are deteriorated, but also the coefficient of friction tends to increase, and wear resistance Tend to decrease. In the present specification, the viscosity index means a viscosity index measured in accordance with JIS K 2283-1993.

  The content of sulfur in the lubricating base oil is preferably 0.03% by mass (300 ppm by mass) or less, more preferably 50 ppm by mass or less, and particularly preferably 10 ppm by mass or less from the viewpoint of oxidation stability. 1 mass ppm or less may be sufficient.

<(B) Calcium detergent and (C) Magnesium detergent>
(B) As the calcium-based detergent (hereinafter sometimes referred to simply as “component (B)”), known calcium-based detergents such as calcium sulfonate, calcium phenate, and calcium salicylate can be used. Of these, calcium sulfonate and / or calcium salicylate can be preferably used.
As the (C) magnesium-based detergent (hereinafter sometimes referred to simply as “component (C)”), known magnesium-based detergents such as magnesium sulfonate, magnesium phenate, magnesium salicylate, and the like can be used. Among these, magnesium sulfonate can be preferably used.

Preferred examples of the calcium or magnesium sulfonate detergent include calcium or magnesium salts of alkyl aromatic sulfonic acids obtained by sulfonating alkyl aromatic compounds, or basic or overbased salts thereof. The weight average molecular weight of the alkyl aromatic compound is preferably 400-1500.
Examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid. As petroleum sulfonic acid here, what sulfonated the alkyl aromatic compound of the lubricating oil fraction of mineral oil, what is called mahoganic acid etc. byproduced at the time of white oil manufacture are mentioned. In addition, as an example of synthetic sulfonic acid, linear or branched alkyl obtained by recovering a by-product in an alkylbenzene production plant that is a raw material of a detergent or by alkylating benzene with polyolefin Examples include sulfonated alkylbenzene having a group. Another example of the synthetic sulfonic acid is a sulfonated alkyl naphthalene such as dinonylnaphthalene. Moreover, there is no restriction | limiting in particular as a sulfonating agent at the time of sulfonating these alkyl aromatic compounds, For example, fuming sulfuric acid and anhydrous sulfuric acid can be used.

  Preferred examples of the calcium or magnesium phenate detergent include calcium salts or overbased salts of compounds having the structure represented by the following general formula (1).

In general formula (1), R ¹ represents a linear or branched chain having 6 to 21 carbon atoms, a saturated or unsaturated alkyl group or alkenyl group, a represents the degree of polymerization, and represents an integer of 1 to 10, A represents a sulfide (—S—) group or a methylene (—CH ₂ —) group, and b represents an integer of 1 to 3. R ¹ may be a combination of two or more different groups.

The number of carbon atoms of ^{R 1} in the general formula (1) is preferably 6 to 18, more preferably 9 to 15. If the carbon number of R ¹ is less than 6, the solubility in the base oil may be poor. On the other hand, if the carbon number of R ¹ exceeds 18, the production may be difficult and the heat resistance may be poor.

  The degree of polymerization a in the general formula (1) is preferably 1 to 3. When the degree of polymerization a is within this range, the heat resistance can be increased.

  Preferred examples of the calcium or magnesium salicylate detergent include calcium or magnesium salicylate or a basic salt or an overbased salt thereof. Preferred examples of the calcium or magnesium salicylate herein include compounds represented by the following general formula (2).

In the general formula (2), R ² each independently represents an alkyl group or alkenyl group having 14 to 30 carbon atoms, c represents 1 or 2, and is preferably 1. When s = 2, R ² may be a combination of different groups.

  As a preferable form of the calcium or magnesium salicylate detergent, calcium or magnesium salicylate or a basic salt or an overbased salt thereof in which s = 1 in the general formula (2) can be mentioned.

  The method for producing calcium or magnesium salicylate is not particularly limited, and a known method for producing monoalkyl salicylate can be used. For example, monoalkyl salicylic acid obtained by alkylation with olefin using phenol as a starting material and then carboxylation with carbon dioxide gas or the like, or alkylation with an equivalent amount of the above olefin using salicylic acid as a starting material. The obtained monoalkyl salicylic acid or the like is reacted with a metal base such as an oxide or hydroxide of calcium or magnesium, or these monoalkyl salicylic acid is once converted into an alkali metal salt such as sodium salt or potassium salt. Calcium or magnesium salicylate can be obtained by exchanging metal with calcium salt or magnesium salt.

  The method for obtaining overbased calcium or magnesium sulfonate, phenate, or salicylate is not particularly limited. For example, calcium sulfonate, phenate, or salicylate is converted to calcium base such as calcium hydroxide in the presence of carbon dioxide gas. By reacting with, an overbased calcium sulfonate, phenate, or salicylate can be obtained. For example, an overbased magnesium sulfonate, phenate, or salicylate can be obtained by reacting magnesium sulfonate, phenate, or salicylate with a magnesium base such as magnesium hydroxide in the presence of carbon dioxide gas.

  Component (B) preferably contains at least one overbased calcium-based detergent, and component (C) preferably contains at least one overbased magnesium-based detergent. The base number of the overbased calcium-based detergent and the overbased magnesium-based detergent is preferably 100 to 500 mgKOH / g, more preferably 150 to 500 mgKOH / g.

  The content of the component (B) in the lubricating oil composition is 0.05 to 0.10% by mass, preferably 0.050 to 0.095% by mass, based on the total amount of the lubricating oil composition. Preferably it is 0.053-0.090 mass%. The content may be 0.070 to 0.090% by mass in one embodiment and 0.070 to 0.080% by mass in another embodiment. When the content of the component (B) is equal to or higher than the lower limit, it is possible to increase the friction coefficient of the brass synchronizer ring and reduce the stick torque of the brass synchronizer ring. Moreover, it becomes possible to reduce the stick torque of a brass-type synchronizer ring because content of (B) component is below the said upper limit.

  The content of the component (C) in the lubricating oil composition is 0.03 to 0.07% by mass, preferably 0.035 to 0.070% by mass, based on the total amount of the lubricating oil composition. Preferably it is 0.040-0.069 mass%. The content may be 0.045 to 0.069% by mass in one embodiment, and 0.045 to 0.055% by mass in another embodiment. When the content of the component (C) is equal to or higher than the lower limit, it is possible to increase the friction coefficient of the brass synchronizer ring and reduce the stick torque of the brass synchronizer ring. Moreover, it becomes possible to reduce the stick torque of a brass-type synchronizer ring because content of (C) component is below the said upper limit.

The calcium content and magnesium content in the lubricating oil composition must satisfy the following formula (1).
1.0 ≦ Ca / Mg ≦ 2.0 (1)
(In formula (1), Ca is the calcium content (unit: mass%) in the composition, and Mg is the magnesium content (unit: mass%) in the composition.)
When the value of the formula (1) is within the above range, the friction coefficient of the brass synchronizer ring can be increased, and the stick torque of the brass synchronizer ring can be reduced.

<Succinimide ashless dispersant>
In one preferred embodiment, the lubricating oil composition may further comprise a succinimide ashless dispersant. The succinimide-based ashless dispersant may include a boronated succinimide-based ashless dispersant, a non-boronated succinimide-based ashless dispersant, or a combination thereof. The boronated succinimide-based ashless dispersant contributes to the content of (D) boron-containing additive described later.

  As the succinimide-based ashless dispersant, for example, succinimide having at least one alkyl group or alkenyl group in the molecule or a derivative thereof can be used. Examples of the succinimide having at least one alkyl group or alkenyl group in the molecule include compounds represented by the following general formula (3) or (4).

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

In general formula (4), R ⁴ and R ⁵ each independently represent an alkyl group or alkenyl group having 40 to 400 carbon atoms, and may be a combination of different groups. R ⁴ and R ⁵ are particularly preferably a polybutenyl group. E represents an integer of 0 to 4, preferably 1 to 3. R ⁴ and R ⁵ preferably have 60 or more carbon atoms, and more preferably 350 or less.

When the carbon number of R ^{3 to} R ⁵ in the general formulas (3) and (4) is equal to or greater than the lower limit, good solubility in the lubricating base oil can be obtained. On the other hand, by the number of carbon atoms of R ³ to R ⁵ is not more than the above upper limit, it is possible to improve the low temperature fluidity of lubricating oil compositions.

The alkyl group or alkenyl group (R ^{3 to} R ⁵ ) in the general formulas (3) and (4) may be linear or branched, and preferably, for example, an olefin oligomer such as propylene, 1-butene and isobutene And a branched alkyl group and a branched alkenyl group derived from a co-oligomer of ethylene and propylene. Of these, branched alkyl groups or alkenyl groups derived from oligomers of isobutene conventionally called polyisobutylene, and polybutenyl groups are most preferred.
The suitable number average molecular weight of the alkyl group or alkenyl group (R ^{3 to} R ⁵ ) in the general formulas (3) and (4) is 800 to 3500.

  A succinimide having at least one alkyl group or alkenyl group in the molecule is a so-called monotype succinic acid represented by the general formula (3) in which succinic anhydride is added only to one end of the polyamine chain. An imide and a so-called bis-type succinimide represented by the general formula (4) in which succinic anhydride is added to both ends of the polyamine chain are included. Either the monotype succinimide or the bis type succinimide may be contained in the lubricating oil composition, or both of them may be contained as a mixture.

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

  Examples of the succinimide derivative include (i) the above succinimide, a monocarboxylic acid having 1 to 30 carbon atoms such as a fatty acid, and a polycarboxylic acid having 2 to 30 carbon atoms (for example, oxalic acid, phthalic acid, Trimellitic acid, pyromellitic acid, etc.), their anhydrides or ester compounds, alkylene oxides having 2 to 6 carbon atoms, or hydroxy (poly) oxyalkylene carbonate, and / or remaining amino groups and / or A modified compound by an oxygen-containing organic compound in which a part or all of the imino group is neutralized or amidated; (ii) a residual amino group and / or imino by reacting boric acid with the succinimide described above A boron-modified compound (boronated succinimide), wherein part or all of the groups are neutralized or amidated; (i i) A phosphoric acid-modified compound in which a part or all of the remaining amino group and / or imino group is neutralized or amidated by allowing phosphoric acid to act on the succinimide; (iv) A sulfur-modified compound obtained by allowing a sulfur compound to act on the succinimide; and (v) 2 selected from the above-described succinimide by modification with an oxygen-containing organic compound, boron modification, phosphoric acid modification, and sulfur modification Examples of the modifying compound obtained by combining two or more kinds of modification. Among these derivatives (i) to (v), the heat resistance of the lubricating oil composition is further improved by using a boron-modified compound of alkenyl succinimide, particularly a boron-modified compound of bis-type alkenyl succinimide. be able to.

  The weight average molecular weight of the succinimide ashless dispersant is preferably 1000 to 20000.

  When the lubricating oil composition contains a succinimide-based ashless dispersant, the content is preferably 20 to 200 ppm by mass, more preferably 25 to 150 ppm by mass as the nitrogen content, based on the total amount of the lubricating oil composition. is there. When the content of the succinimide-based ashless dispersant is not less than the above lower limit, the coking resistance (heat resistance) of the lubricating oil composition can be sufficiently improved. Further, when the content of the succinimide-based ashless dispersant is not more than the above upper limit value, fuel economy can be kept high.

<(D) Boron-containing additive>
In one preferred embodiment, the lubricating oil composition comprises (D) a boron-containing additive (hereinafter sometimes referred to simply as “(D) component”) in an amount of 40 to 200 mass as a boron amount based on the total amount of the composition. Contains ppm.

Preferable examples of the component (D) include the following (D1) and (D2).
(D1) Borated succinimide-based ashless dispersant (hereinafter sometimes referred to as “(D1) component”); and (D2) boric acid ester compound (hereinafter referred to as “(D2) component”). ).
The lubricating oil composition may contain the component (D1), the component (D2), or both the component (D1) and the component (D2) as the component (D). However, the lubricating oil composition preferably contains at least the component (D1).

(D1) The details of the boronated succinimide ashless dispersant are as described above.
(D2) As the borate compound, one or more borate compounds represented by the following general formula (5) can be used.

（一般式（５）中、Ｒ^６は炭素数１〜３０のヒドロカルビル基であり、Ｒ^７及びＲ^８はそれぞれ独立に、水素原子または炭素数１〜３０のヒドロカルビル基である。）

(In General Formula (5), R ⁶ is a hydrocarbyl group having 1 to 30 carbon atoms, and R ⁷ and R ⁸ are each independently a hydrogen atom or a hydrocarbyl group having 1 to 30 carbon atoms.)

  Examples of the hydrocarbyl group include an alkyl group (which may have a ring structure), an alkenyl group (the position of the double bond is arbitrary and may have a ring structure), an aryl group, and an alkylaryl group. Alkenylaryl group, arylalkyl group, arylalkenyl group and the like.

  Examples of the alkyl group include various linear or branched alkyl groups. Examples of the alkyl group having a ring structure include an alkylcycloalkyl group and a cycloalkylalkyl group. Examples of the cycloalkyl group include cycloalkyl groups having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The substitution position on the cycloalkyl ring is arbitrary.

  Examples of the alkenyl group include various linear or branched alkenyl groups. Examples of the alkenyl group having a ring structure include an alkylcycloalkenyl group, an alkenylcycloalkyl group, a cycloalkenylalkyl group, and a cycloalkenylalkenyl group. The cycloalkyl group is the same as described above. Examples of the cycloalkenyl group include a cycloalkenyl group having 5 to 7 carbon atoms such as a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The substitution position on the cycloalkenyl ring and cycloalkyl ring is arbitrary.

  Examples of the aryl group include a phenyl group and a naphthyl group. The aryl group may have a hydrocarbyl substituent. In the alkylaryl group, alkenylaryl group, arylalkyl group, and arylalkenyl group, the substitution position on the aryl group is arbitrary.

  The hydrocarbyl group having 1 to 30 carbon atoms in the general formula (5) is preferably an alkyl or alkenyl group, and more preferably an alkyl group. The number of carbon atoms is preferably 3 or more, more preferably 5 or more, and in one embodiment 6 or more. Further, it is preferably 24 or less, more preferably 12 or less, and in one embodiment, 8 or less. When the carbon number of the hydrocarbyl group is equal to or more than the lower limit, it is possible to increase the solubility and increase the friction coefficient of the synchronizer ring. When the carbon number of the hydrocarbyl group exceeds the above upper limit, the friction coefficient of the synchronizer ring tends to decrease.

In the general formula (5), it is preferable that at least one of R ⁷ and R ⁸ are hydrogen atoms, and more preferably both R ⁷ and R ⁸ are hydrogen atoms. By using the component (D2) in such a form, it is possible to increase the strength of the lubricating film in the boundary lubrication region and improve the seizure resistance and the wear resistance.

Preferred examples of the component (D2) include borate compounds in which R ⁶ is an alkyl or alkenyl group having 3 to 12 carbon atoms and R ⁷ and R ⁸ are hydrogen atoms in the general formula (5). Can do.

  The content of component (D) in the lubricating oil composition (when the lubricating oil composition contains a plurality of boron-containing additives, the total content thereof) is the amount of boron based on the total amount of the lubricating oil composition. It is 40-200 mass ppm as (boron atom conversion amount), Preferably it is 50 mass ppm or more. The content may be 100 ppm by mass or more in one embodiment, and 150 ppm by mass or less in one embodiment. When content of (D) component is more than the said lower limit, it becomes possible to improve the seizure resistance, the fatigue life, and the friction coefficient of the brass synchronizer ring. Moreover, it becomes possible to improve a fatigue life because content of (D) component is below the said upper limit.

It is preferable that the calcium content, the magnesium content, and the boron content in the lubricating oil composition satisfy the following formula (2).
0.5 ≦ (Ca / Mg) × CB × 10 ⁻² (2)
(In formula (2), Ca is the calcium content (unit: mass%) in the composition, Mg is the magnesium content (unit: mass%) in the composition, and CB is boron in the composition. Content (unit: ppm by mass).)
When the value of the formula (2) is 0.5 or more, it becomes possible to improve the seizure resistance, the fatigue life, and the friction coefficient of the brass synchronizer ring. Also, the stick torque of the brass synchronizer ring can be reduced.

<(E) Thiadiazole metal deactivator>
In one preferred embodiment, the lubricating oil composition contains a thiadiazole-based metal deactivator (hereinafter also referred to as “component (E)”) in an amount of 0.005 to 0.00 based on the total amount of the lubricating oil composition. Contains 50% by mass. (E) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  Preferred examples of the component (E) include a 1,3,4-thiadiazole compound represented by the following general formula (6), a 1,2,4-thiadiazole compound represented by the following general formula (7), and the following: A 1,2,3-thiadiazole compound represented by the general formula (8) can be given.

（一般式（６）〜（８）中、Ｒ^９及びＲ^１０は同一でも異なっていてもよく、それぞれ独立に水素又は炭素数１〜２０のヒドロカルビル基を表し；ｆ及びｇは同一でも異なっていてもよく、それぞれ独立に０〜８の整数を表す。）

(In the general formulas (6) to (8), R ⁹ and R ¹⁰ may be the same or different, and each independently represents hydrogen or a hydrocarbyl group having 1 to 20 carbon atoms; f and g are the same or different. And each independently represents an integer of 0 to 8.)

  The content of the component (E) in the lubricating oil composition is 0.005 to 0.50 mass% based on the total amount of the lubricating oil composition. The content of the component (E) is preferably such that the total sulfur content in the lubricating oil composition described below is 1400 to 3000 ppm by mass based on the total amount of the composition. From the viewpoint of setting the total sulfur content in the lubricating oil composition within the above range, the content of the component (E) in the lubricating oil composition is preferably 0.008 to 0.40 on the basis of the total amount of the lubricating oil composition. It is mass%, More preferably, it is 0.01-0.30 mass%. The content may be 0.05 to 0.30% by mass in one embodiment, and 0.05 to 0.20% by mass in another embodiment. When the content of the component (E) is 0.005% by mass or more, it becomes possible to improve the seizure resistance (load capacity). Further, when the content of the component (E) is 0.50% by mass or less, the fatigue life, the friction coefficient of the brass synchronizer ring, and the oxidation stability can be improved.

<Sulfur content in lubricating oil composition>
The sulfur content in the lubricating oil composition is preferably 1400 to 3000 mass ppm, more preferably 1500 to 3000 mass ppm, and even more preferably 1550 to 2900 mass ppm, based on the total amount of the lubricating oil composition. The content may be 1700-2900 ppm by mass in one embodiment and 1700-2400 ppm by mass in another embodiment. When the sulfur content in the lubricating oil composition is at least the above lower limit value, it becomes possible to improve the seizure resistance and the fatigue life. Further, when the sulfur content in the lubricating oil composition is not more than the above upper limit value, it is possible to increase the wear resistance, fatigue life, friction coefficient of brass synchronizer ring, and oxidation stability.

((F) Sulfur-containing extreme pressure agent)
In addition to the above component (E), the lubricating oil composition contains at least one sulfur-containing extreme pressure agent (hereinafter referred to as “(F) component” so that the sulfur content in the lubricating oil composition falls within the above range. In some cases. (E) Sulfur-containing extreme pressure agents other than component include sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl (poly) sulfide, alkylthiocarbamoyl compounds, thiocarbamate compounds, thioterpene compounds, dialkylthiodipropionate compounds A known sulfur-containing extreme pressure agent or phosphorus-sulfur-containing extreme pressure agent such as sulfur mineral oil, zinc dithiocarbamate compound, molybdenum dithiocarbamate compound, zinc dithiophosphate, and molybdenum dithiophosphate can be used. A sulfur containing additive may be used individually by 1 type, and may be used in combination of 2 or more type.

  Sulfurized fats and oils are products obtained by reacting sulfur or sulfur-containing compounds with fats and oils (lard oil, whale oil, vegetable oil, fish oil, etc.). The sulfur content in the sulfurized fat is not particularly limited, but is usually 5 to 30% by weight.

As the sulfurized fatty acid, a product obtained by sulfurizing an unsaturated fatty acid by any method can be used, and specific examples include sulfurized oleic acid.
As the sulfurized ester, an unsaturated fatty acid ester (for example, a product obtained by reacting an unsaturated fatty acid (such as oleic acid, linoleic acid, or a fatty acid extracted from the above-mentioned animal and vegetable oils and fats) and various alcohols is arbitrarily selected. Products obtained by sulfiding by the above method can be used, and specifically, sulfurized methyl oleate, sulfurized rice bran fatty acid octyl and the like can be exemplified.

  Examples of the sulfurized olefin include compounds represented by the following general formula (9). This compound can be obtained by reacting an olefin having 2 to 15 carbon atoms or a dimer to tetramer thereof with a sulfurizing agent such as sulfur or sulfur chloride. As the olefin, propylene, isobutene, diisobutene and the like can be preferably used.

（一般式（９）中、Ｒ^１１は炭素数２〜１５のアルケニル基を表し、Ｒ^１２は炭素数２〜１５のアルキル基又はアルケニル基を表し、ｈは１〜８の整数を示す。）

(In General Formula (9), R ¹¹ represents an alkenyl group having 2 to 15 carbon atoms, R ¹² represents an alkyl group or alkenyl group having 2 to 15 carbon atoms, and h represents an integer of 1 to 8)

Dihydrocarbyl (poly) sulfide is a compound represented by the following general formula (10). Here, when R ¹³ and R ¹⁴ are alkyl groups, they may be referred to as alkyl sulfides.

（一般式（１０）中、Ｒ^１３及びＲ^１４は同一でも異なっていてもよく、それぞれ独立に炭素数１〜２０のアルキル基（直鎖でも分岐鎖でもよく、環状構造を有していてもよい。）、炭素数６〜２０のアリール基、炭素数７〜２０のアルキルアリール基、又は炭素数７〜２０のアリールアルキル基を表し、ｉは１〜８の整数を表す。）

(In General Formula (10), R ¹³ and R ¹⁴ may be the same or different, and each independently represents an alkyl group having 1 to 20 carbon atoms (which may be linear or branched, and may have a cyclic structure). It represents an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or an arylalkyl group having 7 to 20 carbon atoms, and i represents an integer of 1 to 8).

  Examples of the alkylthiocarbamoyl compound include compounds represented by the following general formula (11).

（一般式（１１）中、Ｒ^１５〜Ｒ^１８は同一でも異なっていてもよく、それぞれ独立に炭素数１〜２０のアルキル基を表し、ｊは１〜８の整数を表す。）

(In the general formula (11), R ^{15 to} R ¹⁸ may be the same or different, each independently represents an alkyl group having 1 to 20 carbon atoms, and j represents an integer of 1 to 8).

  Examples of the alkylthiocarbamate compound include compounds represented by the following general formula (12).

（一般式（１２）中、Ｒ^１９〜Ｒ^２２は同一でも異なっていてもよく、それぞれ炭素数１〜２０のアルキル基を示し、Ｒ^２３は炭素数１〜１０のアルキル基を示す。）

(In General Formula (12), R ^{19 to} R ²² may be the same or different, and each represents an alkyl group having 1 to 20 carbon atoms, and R ²³ represents an alkyl group having 1 to 10 carbon atoms.)

Examples of the thioterpene compound include a reaction product of phosphorus pentasulfide and pinene.
Examples of the dialkylthiodipropionate compound include dilauryl thiodipropionate and distearyl thiodipropionate.

  Sulfided mineral oil is a substance obtained by dissolving elemental sulfur in mineral oil. Although it does not restrict | limit especially as mineral oil used for sulfide mineral oil, Specifically, it applies by combining well-known refinement | purification processing suitably with respect to the lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation. Examples include refined paraffinic mineral oil and naphthenic mineral oil. In addition, as the elemental sulfur, any form such as a lump, powder, or molten liquid may be used. The sulfur content in the sulfide mineral oil is not particularly limited, but is usually 0.05 to 1.0% by weight based on the total amount of sulfide mineral oil.

  A compound represented by the following general formula (13) can be used as the zinc dithiocarbamate compound, and a compound represented by the following general formula (14) can be used as the molybdenum dithiocarbamate compound.

（一般式（１３）中、Ｒ^２４〜Ｒ^２７は同一でも異なっていてもよく、それぞれ独立に炭素数１以上のヒドロカルビル基を表す。）

(In the general formula (13), R ^{24 to} R ²⁷ may be the same or different and each independently represents a hydrocarbyl group having 1 or more carbon atoms.)

（一般式（１４）中、Ｒ^２８〜Ｒ^３１は同一でも異なっていてもよく、それぞれ独立に炭素数１以上のヒドロカルビル基を表し、Ｘ^１〜Ｘ^４はそれぞれ独立に酸素原子又は硫黄原子を表す。）

(In the general formula (14), R ^{28 to} R ³¹ may be the same or different and each independently represents a hydrocarbyl group having 1 or more carbon atoms, and X ^{1 to} X ⁴ each independently represents an oxygen atom or a sulfur atom. Represents.)

  As the zinc dithiophosphate compound, a compound represented by the following general formula (15) can be used.

（一般式（１５）中、Ｒ^３２〜Ｒ^３５は同一でも異なっていてもよく、それぞれ独立に炭素数３〜１８のヒドロカルビル基を表す。）

(In the general formula (15), R ^{32 to} R ³⁵ may be the same or different, and each independently represents a hydrocarbyl group having 3 to 18 carbon atoms.)

  As the molybdenum dithiophosphate compound, a compound represented by the following general formula (16) can be used.

（一般式（１６）中、Ｒ^３６〜Ｒ^３９は同一でも異なっていてもよく、それぞれ独立に炭素数１以上のヒドロカルビル基を表し、Ｘ^５〜Ｘ^８はそれぞれ独立に酸素原子又は硫黄原子を表す。）

(In General Formula (16), R ^{36 to} R ³⁹ may be the same or different and each independently represents a hydrocarbyl group having 1 or more carbon atoms, and X ^{5 to} X ⁸ each independently represents an oxygen atom or a sulfur atom. Represents.)

<Phosphorus content in lubricating oil composition>
The phosphorus content in the lubricating oil composition is preferably 500 to 1000 ppm by mass, more preferably 550 to 950 ppm by mass, based on the total amount of the lubricating oil composition. The content may be 600 to 950 ppm by mass in one embodiment and 600 to 800 ppm by mass in another embodiment. When the phosphorus content in the lubricating oil composition is not less than the above lower limit, it is possible to improve the wear resistance and fatigue life. Further, when the phosphorus content in the lubricating oil composition is not more than the above upper limit value, it becomes possible to improve the seizure resistance and the fatigue life.

((G) Phosphorus-containing antiwear agent)
The lubricating oil composition contains one or more phosphorus-containing antiwear agents (hereinafter sometimes referred to as “component (G)”) so that the phosphorus content in the lubricating oil composition falls within the above range. It is preferable. Examples of the phosphorus-containing antiwear agent include, in addition to the phosphorus-sulfur-containing extreme pressure agent, a compound represented by the following general formula (17), a compound represented by the following general formula (18), and metal salts thereof. Mention may be made of phosphorus-containing antiwear agents such as ammonium salts. A phosphorus containing additive may be used individually by 1 type, and may be used in combination of 2 or more type.

（一般式（１７）中、Ｘ^９、Ｘ^１０、及びＸ^１１は、それぞれ独立に酸素原子または硫黄原子を表し；Ｒ^４０は炭素数１〜３０の炭化水素基を表し；Ｒ^４１及びＲ^４２はそれぞれ独立に水素原子または炭素数１〜３０の炭化水素基を表し；Ｒ^４０、Ｒ^４１、及びＲ^４２は同一でも相互に異なっていてもよい。）

(In General Formula (17), X ⁹ , X ¹⁰ , and X ¹¹ each independently represent an oxygen atom or a sulfur atom; R ⁴⁰ represents a hydrocarbon group having 1 to 30 carbon atoms; R ⁴¹ and R ⁴² Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms; R ⁴⁰ , R ⁴¹ , and R ⁴² may be the same or different from each other.

（一般式（１８）中、Ｘ^１２、Ｘ^１３、Ｘ^１４、及びＸ^１５は、それぞれ独立に酸素原子または硫黄原子を表し；Ｒ^４３は炭素数１〜３０の炭化水素基を表し；Ｒ^４４及びＲ^４５はそれぞれ独立に水素原子または炭素数１〜３０の炭化水素基を表し；Ｒ^４３、Ｒ^４４、及びＲ^４５は同一でも相互に異なっていてもよい。）

(In the general formula (18), X ¹² , X ¹³ , X ¹⁴ and X ¹⁵ each independently represent an oxygen atom or a sulfur atom; R ⁴³ represents a hydrocarbon group having 1 to 30 carbon atoms; R ⁴⁴ And R ⁴⁵ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms; R ⁴³ , R ⁴⁴ , and R ⁴⁵ may be the same or different from each other.

  Examples of the hydrocarbon group having 1 to 30 carbon atoms in the general formulas (17) and (18) include an alkyl group, a cycloalkyl group, an alkenyl group, an alkyl-substituted cycloalkyl group, an aryl group, an alkyl-substituted aryl group, and an aryl group. An alkyl group etc. can be mentioned. The hydrocarbon group is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, and in one embodiment, an alkyl group having 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms, An aryl group or an alkylaryl group.

  Specific examples of the metal that forms a metal salt with the phosphorus compound represented by the general formula (17) or (18) include alkali metals such as lithium, sodium, potassium, and cesium, calcium, magnesium, barium, and the like. Alkaline earth metals, heavy metals such as zinc, copper, iron, lead, nickel, silver, and manganese. Among these, alkaline earth metals such as calcium and magnesium, zinc, or combinations thereof are preferable.

  Examples of nitrogen-containing compounds that form ammonium salts with phosphorus compounds represented by the general formula (17) or (18) include ammonia, monoamines, diamines, polyamines, and alkanolamines. More specifically, nitrogen-containing compounds represented by the following general formula (19); alkylene diamines such as methylene diamine, ethylene diamine, propylene diamine, and butylene diamine; diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine And the like, and combinations thereof.

（一般式（１９）中、Ｒ^４６〜Ｒ^４８はそれぞれ独立に、水素原子、炭素数１〜８のヒドロカルビル基、又は水酸基を有する炭素数１〜８のヒドロカルビル基を表し；Ｒ^４６〜Ｒ^４８のうち少なくとも１つは炭素数１〜８のヒドロカルビル基、又は水酸基を有する炭素数１〜８のヒドロカルビル基である。）

(In General Formula (19), R ^{46 to} R ⁴⁸ each independently represents a hydrogen atom, a hydrocarbyl group having 1 to 8 carbon atoms, or a hydrocarbyl group having 1 to 8 carbon atoms having a hydroxyl group; R ^{46 to} R ^48. At least one of them is a C1-C8 hydrocarbyl group or a C1-C8 hydrocarbyl group having a hydroxyl group.)

  As the phosphorus-containing additive, among the above-mentioned compounds, a phosphite compound can be preferably used. Among them, an alkyl group, aryl group, or alkylaryl group having 3 to 18 carbon atoms (preferably 4 to 12 carbon atoms) can be used. The hydrogen phosphite having is particularly preferred. For example, at least one hydrogen phosphite selected from diphenyl hydrogen phosphite, triphenyl phosphite, dibutyl hydrogen phosphite, and dilauryl hydrogen phosphite can be preferably used.

It is preferable that the sulfur content, the phosphorus content, and the boron content in the lubricating oil composition satisfy the following formula (3).
0.4 ≦ [CB / (CP × CS)] × 10 ⁴ ≦ 1.6 (3)
(In formula (3), CB is the boron content (unit: mass ppm) in the composition, CP is the phosphorus content (unit: mass ppm) in the composition, and CS is sulfur in the composition. Content (unit: ppm by mass).)
When the value of the above formula (3) is 0.4 or more, it becomes possible to improve the seizure resistance, the wear resistance, the fatigue life, the friction coefficient of the brass synchronizer ring, and the oxidation stability. Further, when the value of the above formula (3) is 1.6 or less, it becomes possible to improve the seizure resistance, the wear resistance, the fatigue life, and the friction coefficient of the brass synchronizer ring.

<Viscosity characteristics of lubricating oil composition>
The kinematic viscosity at 25 ° C. of the lubricating oil composition is 65 mm ² / s or less. Moreover, it is preferably 37 mm ² / s or more, more preferably 40 mm ² / s or more, and in one embodiment may be 50 mm ² / s or more. When the kinematic viscosity at 25 ° C. of the lubricating oil composition is 65 mm ² / s or less, fuel economy can be improved. Moreover, when the kinematic viscosity at 25 ° C. of the lubricating oil composition is not less than the above lower limit value, it becomes possible to improve the seizure resistance and the fatigue life.

  The viscosity index of the lubricating oil composition is 150 or more. The upper limit of the viscosity index of the lubricating oil composition is not particularly limited, but is usually 300 or less, and may be 200 or less in one embodiment. When the viscosity index of the lubricating oil composition is 150 or more, fuel economy can be improved.

<(H) Viscosity index improver>
In one preferred embodiment, the lubricating oil composition contains a viscosity index improver (hereinafter sometimes referred to as “(H) component”) so that the kinematic viscosity and viscosity index at 25 ° C. are within the above ranges. Further may be included. As the component (H), a known viscosity index improver can be used without particular limitation. For example, polymethacrylate, ethylene-α-olefin copolymer and its hydride, copolymer of α-olefin and ester monomer having polymerizable unsaturated bond, polyisobutylene and its hydride, styrene-diene copolymer Examples thereof include a hydride of a polymer, a styrene-maleic anhydride copolymer, and a polyalkylstyrene. Among these, polymethacrylate, ethylene-α-olefin copolymer or a hydride thereof, or a combination thereof can be preferably used. These viscosity index improvers may be dispersed or non-dispersed.

  The weight average molecular weight and content of the viscosity index improver are selected so that the kinematic viscosity and viscosity index at 25 ° C. of the lubricating oil composition are within the above ranges. The larger the weight average molecular weight of the viscosity index improver, the smaller the required content, and the smaller the weight average molecular weight, the greater the required content. In one embodiment, the weight average molecular weight of the viscosity index improver is, for example, 5 The content may be, for example, 3.0 to 20.0% by mass, preferably 4.0 to 15.0% by mass based on the total amount of the composition. .

<(I) Antioxidant>
In one preferred embodiment, the lubricating oil composition may further comprise an antioxidant (hereinafter sometimes referred to as “component (I)”). As antioxidant, well-known antioxidants, such as a phenolic antioxidant and an amine antioxidant, can be especially used without a restriction | limiting. Examples include amine antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated-α-naphthylamine, 2,6-di-t-butyl-4-methylphenol, 4,4′-methylenebis ( 2,6-di-t-butylphenol) and the like. The content of the antioxidant in the lubricating oil composition is preferably 0.1 to 5.0% by mass, more preferably 0.2% by mass or more, and more preferably based on the total amount of the lubricating oil composition. It is 2.0 mass% or less.

<(J) Friction modifier>
In one preferred embodiment, the lubricating oil composition may further contain a friction modifier other than the above-mentioned components (F) and (G) (hereinafter sometimes referred to as “(J) component”). According to the lubricating oil composition containing the component (J), the slipping out of the synchronizer ring from the synchro cone becomes better due to the reduction of the coefficient of static friction. Furthermore, since the resistance when pushing the teeth of the sleeve into the teeth of the spline of the floating gear after matching the rotational speeds of the floating gear and the sleeve is reduced, the shifting feeling is improved. As the component (J), one or more friction modifiers selected from molybdenum-based friction modifiers other than the components (F) and (G) and ashless friction modifiers can be used. The content of the friction modifier is preferably 0.01 to 2.0% by mass, more preferably 0.5% by mass or more, and more preferably 1.0% by mass or less, based on the total amount of the lubricating oil composition. is there.

  Examples of the molybdenum friction modifier other than the component (F) and the component (G) include molybdenum compounds (for example, molybdenum oxide such as molybdenum dioxide and molybdenum trioxide, orthomolybdic acid, paramolybdic acid, and (poly) molybdenum sulfide. Molybdic acids such as acids, metal salts of these molybdates, molybdates such as ammonium salts, molybdenum sulfides such as molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, and molybdenum polysulfide, molybdenum sulfides, and metal sulfides Salts or amine salts, molybdenum halides such as molybdenum chloride, etc.) and sulfur-containing organic compounds (eg, alkyl (thio) xanthate, thiadiazole, mercaptothiadiazole, thiocarbonate, tetrahydrocarbyl thiuram disulfide, bis (di (thio Hydrocarbyl dithiophosphonates) disulfides, organic (poly) sulfides, sulfurized esters, etc.) or complexes with other organic compounds, and the like; An organic molybdenum compound containing sulfur, such as a complex of The organic molybdenum compound may be a mononuclear molybdenum compound or a polynuclear molybdenum compound such as a dinuclear molybdenum compound or a trinuclear molybdenum compound.

  Moreover, as a molybdenum type friction modifier other than (F) component and (G) component, the organic molybdenum compound which does not contain sulfur as a structural element can also be used. Specific examples of organic molybdenum compounds that do not contain sulfur as a constituent element include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols. Complexes, molybdenum salts of organic acids and molybdenum salts of alcohols are preferred.

  When the lubricating oil composition contains a molybdenum friction modifier other than the (F) component and the (G) component as the (J) component, the content is 0.01 to 2.0 mass based on the total amount of the lubricating oil composition. % Is preferred.

  As the ashless friction modifier, a known oil-based friction modifier can be used without particular limitation. Examples of the ashless friction modifier include compounds having 6 to 50 carbon atoms containing one or more heteroelements selected from an oxygen atom, a nitrogen atom, and a sulfur atom in the molecule. More specifically, at least one alkyl group or alkenyl group having 6 to 30 carbon atoms, preferably a linear alkyl group having 6 to 30 carbon atoms, a straight chain alkenyl group, a branched alkyl group, or a branched alkenyl group is included in the molecule. Ashless friction modifiers such as amine compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, urea compounds, hydrazide compounds, and the like can be preferably used.

  When the lubricating oil composition contains an ashless friction modifier as the component (J), the content is preferably 0.01% by mass or more, more preferably 0.1% by mass, based on the total amount of the lubricating oil composition. Or more, preferably 2% by mass or less, more preferably 1.0% by mass or less.

<Other additives>
In one embodiment, the lubricating oil composition comprises a pour point depressant, a corrosion inhibitor other than the component (E), a rust inhibitor, a metal deactivator other than the component (E), a demulsifier, an antifoaming agent, And one or more additives selected from colorants.

  As the pour point depressant, a known pour point depressant such as a polymethacrylate polymer can be used without particular limitation, depending on the properties of the lubricating base oil to be used. When the lubricating oil composition contains a pour point depressant, the content thereof is usually 0.1% by weight or more and 20.0% by weight or less based on the total amount of the composition.

  As the corrosion inhibitor other than the component (E), for example, known corrosion inhibitors such as benzotriazole, tolyltriazole, and imidazole compounds can be used. When the lubricating oil composition contains a corrosion inhibitor other than the component (E), the content is usually 0.005 to 5% by mass based on the total amount of the lubricating oil composition.

  As the rust preventive agent, for example, known rust preventive agents such as petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinate, and polyhydric alcohol ester can be used without particular limitation. When the lubricating oil composition contains these rust inhibitors, the content thereof is usually 0.1% by weight or more and 2.0% by weight or less based on the total amount of the composition.

  Examples of the metal deactivator other than the component (E) include imidazoline, pyrimidine derivatives, mercaptobenzothiazole, benzotriazole and derivatives thereof, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio). A known metal deactivator such as propiononitrile can be used. When the lubricating oil composition contains these metal deactivators, the content thereof is usually 0.05% by weight or more and 1.0% by weight or less based on the total amount of the composition.

  As the demulsifier, for example, known demulsifiers such as polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether are used without particular limitation. Is possible. When the lubricating oil composition contains these demulsifiers, the content is usually 0.1% by weight or more and 1.0% by weight or less based on the total amount of the composition.

  As the antifoaming agent, for example, known antifoaming agents such as silicone, fluorosilicone, and fluoroalkyl ether can be used. When the lubricating oil composition contains these antifoaming agents, the content is usually 0.001% by mass or more and 0.01% by mass or less based on the total amount of the composition.

  As the colorant, for example, a known colorant such as an azo compound can be used without particular limitation.

  Hereinafter, based on an Example and a comparative example, it demonstrates further more concretely about this invention. However, the present invention is not limited to these examples.

<Examples 1-24 and Comparative Examples 1-5>
As shown in Tables 1 to 5, lubricating oil compositions of the present invention (Examples 1 to 24) and comparative lubricating oil compositions (Comparative Examples 1 to 5) were prepared. In the table, “mass%” for the base oil means mass% based on the total amount of the base oil, “mass%” for other components means mass% based on the total amount of the composition, and “mass ppm” means the composition. It means mass ppm on the basis of the total amount of goods. Details of the components are as follows.

((A) Lubricating base oil)
A-1: Hydrorefined mineral oil (Group II, kinematic viscosity (40 ° C.): 12.65 mm ² / s, kinematic viscosity (100 ° C.): 3.1 mm ² / s, viscosity index: 104, sulfur content: 1 mass (below ppm)
A-2: Hydrorefined mineral oil (Group III, kinematic viscosity (40 ° C.): 36.11 mm ² / s, kinematic viscosity (100 ° C.): 6.398 mm ² / s, viscosity index: 129, sulfur content: 1 mass (below ppm)
A-3: Hydrorefined mineral oil (Group III, kinematic viscosity (40 ° C.): 18.42 mm ² / s, kinematic viscosity (100 ° C.): 4.2 mm ² / s, viscosity index: 133, sulfur content: 1 mass (below ppm)
A-4: Poly α-olefin (Group IV, kinematic viscosity (40 ° C.): 19 mm ² / s, kinematic viscosity (100 ° C.): 4.1 mm ² / s, viscosity index: 126, pour point: −66 ° C., (Flash point: 220 ° C)
A-5: Monoester base oil (Group V, 2-ethylhexyl oleate, kinematic viscosity (40 ° C.): 8.4 mm ² / s, kinematic viscosity (100 ° C.): 2.7 mm ² / s, viscosity index: 174 )
A-6: Wax isomerized base oil (Group III, kinematic viscosity (40 ° C.): 9.095 mm ² / s, kinematic viscosity (100 ° C.): 2.603 mm ² / s, viscosity index: 122)

((B) Calcium-based detergent)
B-1: Calcium sulfonate, base number 300 mgKOH / g, Ca: 11.95% by mass
B-2: Calcium sulfonate, base number 17 mg KOH / g, Ca: 2.35% by mass
B-3: Calcium salicylate, base number 192 mgKOH / g, Ca: 6.8% by mass

  (C) Magnesium-based detergent: magnesium sulfonate, base number 400 mgKOH / g, Mg: 9.1% by mass, S: 1.7% by mass

((D) Boron-containing additive)
D-1: Boronated succinimide ashless dispersant, B: 2.0 mass%, N: 2.7 mass%
D-2: Boric acid ester compound (Boric acid ester compound in which R ⁶ is an alkyl or alkenyl group having 3 to 12 carbon atoms and R ⁷ and R ⁸ are hydrogen atoms in general formula (5)), B: 2 .83 mass%

  D-1 ': non-borated succinimide ashless dispersant, N: 2.7% by mass

  (E) thiadiazole compound: a thiadiazole compound having a hydrocarbyl dithio group represented by general formulas (6) to (8), S: 36% by mass

  (F) Sulfur-containing extreme pressure agent: sulfurized ester, S: 39.20% by mass

  (G) Phosphorus-containing antiwear agent: diphenyl hydrogen phosphite, P: 13.2% by mass

((H) viscosity index improver)
H-1: Ethylene-α-olefin copolymer viscosity index improver, weight average molecular weight Mw: 9,000
H-2: Polymethacrylate viscosity index improver, weight average molecular weight Mw: 20,000

  (I) Antioxidant: Diphenylamine

  (J) Friction modifier: oleylamide

(High-speed four-ball test)
Each of the lubricating oil compositions was evaluated for load bearing ability (seizure resistance) and wear resistance of the lubricating oil composition by a high-speed four-ball test based on JPI-5S-40-93.
(1) The final non-seizing load (LNSL) was measured at a rotational speed of 1800 rpm.
(2) The wear scar diameter after operating for 30 minutes at a rotational speed of 1800 rpm, a load of 392 N, and an oil temperature of 80 ° C. was measured.
The results are shown in Tables 1-5.

(FZG gear test)
Each of the lubricating oil compositions was operated using the FZG tester under the following conditions in accordance with the FVA 2 / IV standard, and the fatigue life of the gears until the gears were pitched was evaluated.
Gear: Number of C gear load stages: 12
Oil temperature: 120 ° C
Rotation speed: 650rpm

(Synchronizer ring unit test)
About each lubricating oil composition, the dynamic friction coefficient and stick torque which a brass synchronizer ring showed were measured using the synchronizer ring single-piece | unit friction test apparatus (made by Shinko Construction).
The synchronizer ring unit testing machine has a synchronizer ring and a gear cone provided on the same axis, the synchronizer ring is held movably in the axial direction, and the gear cone is held so as to be rotatable.
The procedure for measuring the dynamic friction coefficient is as follows. In a lubricating gear (oil temperature 80 ° C.), a steel gear cone (inertial mass 0.2 kg · m ² ) rotating at a predetermined rotational speed (300 rpm), a brass synchronizer ring (corn angle 6.3 °, An effective radius of 27 mm) is pressed with a predetermined load (500 N). One cycle consists of pressing for 1.0 second and then separating for 2.0 seconds, and the dynamic friction coefficient was calculated from the average value of the friction torque for 1.0 second at the 500th cycle.
The stick torque measurement procedure is as follows. First, the rotation is stopped by pressing the synchronizer ring against a gear cone that freely rotates at an initial speed of 300 rpm in the same manner as the above-described measurement procedure of the dynamic friction coefficient. When the rotation stops, the synchronizer ring is stuck to the gear cone. Next, in a state where no load is applied to the synchronizer ring, the gear cone is rotated at a predetermined rotational speed (300 rpm), and the torque (stick torque) when the synchronizer ring is peeled off from the counterpart member is measured. The measured value was the maximum of 10 measurements.
The results are shown in Tables 1-5. The larger the dynamic friction coefficient measured in this test, the better the synchronization performance of the synchronizer ring. The smaller the stick torque measured in this test, the better the peelability of the synchronizer ring.

(ISOT oxidation stability test)
Each of the lubricating oil compositions was evaluated for oxidation stability by an ISOT test based on JIS K2514. The test was conducted at an oil temperature of 135 ° C. for 96 hours, and the increase in acid value (mgKOH / g) after the test was measured. The results are shown in Tables 1-5.

(Evaluation results)
The lubricating oil compositions of Examples 1 to 24 showed good results in seizure resistance (load capacity), wear resistance, fatigue life, friction coefficient and stick torque of the synchronizer ring, and oxidation stability.
(A) The lubricating oil composition of Comparative Example 1 in which the kinematic viscosity at 100 ° C. of the lubricating base oil and the kinematic viscosity at 25 ° C. of the composition were less than the lower limit values was poor in seizure resistance and fatigue life.
The lubricating oil composition of Comparative Example 2 in which the content of the component (B) was too small and the values of the formulas (1) and (2) were less than the lower limit value was obtained in the friction coefficient and the stick torque of the synchronizer ring. It was inferior.
The lubricating oil composition of Comparative Example 3 in which the content of the component (B) was excessive and the value of the formula (1) exceeded the upper limit value was inferior in the stick torque of the synchronizer ring.
The lubricating oil composition of Comparative Example 4 in which the content of the component (C) was too small and the value of the formula (1) exceeded the upper limit value was inferior in the friction coefficient and the stick torque of the synchronizer ring.
The lubricating oil composition of Comparative Example 5 in which the content of the component (C) was excessive and the value of the formula (1) was less than the lower limit value was inferior in the stick torque of the synchronizer ring.

Claims (8)

(A) API group II base oil, group III base oil, group IV base oil, or group V base oil, or a mixed base oil thereof having a kinematic viscosity at 100 ° C. of 3.0 to 5.0 mm ² / a lubricating base oil that is s;
(B) The calcium-based detergent is 0.05 to 0.10% by mass as a calcium amount on the basis of the total amount of the composition,
(C) Magnesium-based detergent containing 0.03 to 0.07% by mass as the amount of magnesium based on the total amount of the composition,
The kinematic viscosity at 25 ° C. of the composition is 65 mm ² / s or less,
The viscosity index of the composition is 150 or more,
A lubricating oil composition for a manual transmission, characterized by satisfying the following formula (1).
1.0 ≦ Ca / Mg ≦ 2.0 (1)
(In formula (1), Ca is the calcium content (unit: mass%) in the composition, and Mg is the magnesium content (unit: mass%) in the composition.) (D) The boron-containing additive is contained in an amount of 40 to 200 ppm by mass as a boron amount based on the total amount of the composition,
The lubricating oil composition for manual transmission according to claim 1, wherein the following formula (2) is satisfied.
0.5 ≦ (Ca / Mg) × CB × 10 ⁻² (2)
(In formula (2), Ca is the calcium content (unit: mass%) in the composition, Mg is the magnesium content (unit: mass%) in the composition, and CB is boron in the composition. Content (unit: ppm by mass).)   The lubricating oil composition for manual transmission according to claim 2, comprising (D1) a boronated succinimide-based ashless dispersant, or (D2) a boric acid ester compound, or a combination thereof. Further or non-boronated succinimide ashless dispersant,
The total content of the component (D1) and the non-borated succinimide ashless dispersant is 20 to 200 ppm by mass as a nitrogen content based on the total amount of the composition.
The lubricating oil composition for manual transmission according to claim 3.   (E) The lubricating oil composition for manual transmissions in any one of Claims 1-4 which contains 0.005-0.50 mass% of thiadiazole type metal deactivators on the basis of the composition whole quantity. The sulfur content in the composition is 1400 to 3000 mass ppm based on the total amount of the composition,
The phosphorus content in the composition is 500 to 1000 ppm by mass based on the total amount of the composition,
The lubricating oil composition for manual transmission according to claim 5, wherein the following formula (3) is satisfied.
0.4 ≦ [CB / (CP × CS)] × 10 ⁴ ≦ 1.6 (3)
(In formula (3), CB is the boron content (unit: mass ppm) in the composition, CP is the phosphorus content (unit: mass ppm) in the composition, and CS is sulfur in the composition. Content (unit: ppm by mass).)   (F) The lubricating oil composition for manual transmissions of Claim 6 containing sulfur containing extreme pressure agents other than the said (E) component.   (G) The lubricating oil composition for manual transmissions of Claim 6 or 7 containing a phosphorus containing antiwear agent.