JP2008056735A - Low-friction slide mechanism and lubricant composition used therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-friction slide mechanism which possesses very low friction properties and exhibits more excellent fuel consumption reduction effect than a conventional DLC film member/lubricant composition combination and to provide a lubricant composition used therein. <P>SOLUTION: What are provided are a low-friction slide mechanism wherein at least either of the sliding members has a slide face using diamond, the arithmetic average surface roughness Ra of the slide face using diamond is 0.05 μm or smaller, and a lubricant composition containing a fatty acid ester ashless friction modifier or an aliphatic amine ashless friction modifier intervenes between the sliding faces and a lubricant composition which is used in the low-friction slide mechanism and in which the fatty acid ester ashless friction modifier or the aliphatic amine ashless friction modifier has a 6-30C hydrocarbon group and is contained in an amount of 0.05-3.0% based on the entire weight of the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a low friction sliding mechanism and a lubricating oil composition used therefor, and more specifically, has excellent wear resistance, for example, friction characteristics of various sliding surfaces in an internal combustion engine, a drive train transmission engine, and the like. The present invention relates to a low-friction sliding mechanism capable of improving the stability stably and a lubricating oil composition used therefor.

Warming global environmental problems on a global scale, such as destruction of the ozone layer are largely close-up, especially for CO ₂ reduction that is said to have great influence on the global warming of the whole earth, the regulation value in each country A great deal of attention has been drawn to how to decide.
Regarding CO ₂ reduction, reduction of energy loss due to friction loss of machines and devices, particularly reduction of fuel consumption of automobiles is one of the major issues, and the role played by the sliding material and the lubricant is large.

The role of the sliding material is to express excellent wear resistance and a low coefficient of friction for parts where the friction and wear environment is severe among sliding parts such as engines, electric motors, and fuel pumps. Recently, various hard thin film materials have been applied.
In general, carbon-based materials such as diamond and diamond-like carbon (DLC) films have a friction coefficient in the air and in the absence of lubricating oil, and wear-resistant hard coating materials such as titanium nitride (TiN) and chromium nitride (CrN). Therefore, it is expected as a low friction sliding material.

On the other hand, as a role of lubricating oil, that is, fuel saving measures,
(1) Reduction of viscosity resistance in the fluid lubrication region and agitation resistance in the engine by lowering viscosity, (2) Mixing of optimum friction modifier and various additives, mixing and friction loss under the boundary lubrication region Reduction is recommended.
For example, as a friction modifier, many studies have been made mainly on organic molybdenum compounds such as molybdenum dithiocarbamate (MoDTC) and molybdenum dithiophosphate (MoDTP), and they are used on sliding surfaces made of conventional steel materials. A lubricating oil composition containing an organomolybdenum compound exhibiting an excellent low friction coefficient at the beginning of the start was applied, and the effect was improved.

Specifically, an example of increasing the effect of greatly reducing the friction coefficient by a combination of a DLC film and a lubricating oil composition has been reported (see, for example, Patent Documents 1 and 2).
JP 2003-238882 A Japanese Patent Application Laid-Open No. 2004-155891

  However, in the combination of the DLC film and the lubricating oil composition as described in Patent Document 1 and Patent Document 2, the friction coefficient is about μ = 0.06 to 0.08, and the sliding member further lowers the friction coefficient. The appearance of is desired.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to show extremely excellent low friction characteristics, and a combination of a conventional DLC film member and a lubricating oil composition. Another object of the present invention is to provide a low friction sliding mechanism capable of exhibiting an even better fuel economy effect and a lubricating oil composition used therefor.

  As a result of intensive studies to solve the above problems, the inventors of the present invention used diamond on at least one sliding surface, adjusted the arithmetic average surface roughness Ra of the sliding surface, and formed a lubricating oil composition. It has been found that the above problem can be solved by including an ashless friction modifier, and the present invention has been completed.

That is, the low friction sliding mechanism of the present invention is a low friction sliding mechanism in which at least one sliding member has a sliding surface using diamond.
The arithmetic average surface roughness Ra of the sliding member using the diamond is 0.05 μm or less,
A lubricating oil composition containing a fatty acid ester-based ashless friction modifier and / or an aliphatic amine-based ashless friction modifier is interposed on the sliding surface.

The lubricating oil composition of the present invention is a lubricating oil composition used for a low friction sliding mechanism,
The fatty acid ester-based ashless friction modifier and / or the aliphatic amine-based ashless friction modifier has a hydrocarbon group having 6 to 30 carbon atoms and is included in an amount of 0.05 to 3.0% based on the total amount of the composition. It is characterized by comprising.

  In the present invention, diamond is used for at least one sliding surface, the arithmetic average surface roughness Ra of the sliding surface is adjusted, and the lubricating oil composition contains an ashless friction modifier, which is extremely excellent. It is possible to provide a low-friction sliding mechanism that exhibits low friction characteristics and can exhibit a fuel-saving effect even better than a combination of a conventional DLC film member and a lubricating oil composition, and a lubricating oil composition used therefor.

  Hereinafter, the low friction sliding mechanism of the present invention will be described in more detail. In the present specification and claims, “%” for concentration, content, filling amount and the like represents a mass percentage unless otherwise specified.

As described above, in the low friction sliding mechanism of the present invention, at least one sliding member has a sliding surface using diamond, and the arithmetic average surface roughness Ra of the diamond sliding member is 0.05 μm or less. To do.
The surface of the diamond sliding member only needs to be achieved by coating diamond on part or all of its surface. Further, the lower limit of the surface roughness is about Ra 0.005 at the present time from a technical point of view.

  Further, the low friction sliding mechanism of the present invention has a lubricating oil composition containing either or both of a fatty acid ester-based ashless friction modifier and an aliphatic amine-based ashless friction modifier on the sliding surface. Let

  Thus, by using diamond for at least one sliding member, the sliding surface becomes very smooth, and by using a lubricating oil composition containing the above ashless friction modifier, a significant friction reducing effect is achieved. Is demonstrated.

In addition, as a low friction sliding mechanism of this invention, if the sliding surface which the two sliding member surfaces interposing the said lubricating oil composition contact is comprised, it can be used without limitation at all.
For example, sliding parts of internal combustion engines such as 4-cycle and 2-cycle engines (for example, valve trains, pistons, piston rings, piston skirts, cylinder liners, connecting rods, crankshafts, bearings, bearings, metals, gears, chains, belts, Oil pumps), drive system transmission mechanisms (for example, gears), hard disk drive sliding parts, and other various sliding surfaces that require severe frictional conditions and low friction.

Here, the diamond sliding member is obtained by coating the surface of the substrate with a diamond film.
In general, a polycrystalline diamond film is formed by increasing the temperature of the base material and adopting a process method in vacuum called a thermal CVD (Chemical Vapor Deposition) method. Since the film has relatively large crystal grains, irregularities corresponding to the crystal grain diameter remain on the surface. Therefore, it may be somewhat difficult to finish smoothly to the surface roughness Ra of 0.05 μm or less as defined in the present invention.
For this reason, it is preferable to employ a CVD process using a microwave or plasma for the coating of the diamond film. According to this manufacturing method, a nano-polycrystalline diamond film having a very small crystal grain size can be formed on a substrate, and can be smoothed more easily than the polycrystalline film. Easy to adjust.

In the low friction sliding mechanism of the present invention, it is preferable that the diamond sliding member has a diamond film having a thickness of 0.3 to 5.0 μm on the substrate surface.
If the thickness of the diamond film is less than 0.3 μm, it will be worn away, and if it exceeds 5.0 μm, it will be easy to peel off.

  The metal material used for the substrate is not particularly limited, and examples thereof include iron-based materials, aluminum-based materials, magnesium-based materials, and titanium-based materials.

On the other hand, the counterpart sliding member that slides with the diamond sliding member preferably has an arithmetic average surface roughness Ra of 0.10 μm or less from the viewpoint of sliding stability. In order to realize further low friction, it is preferable that the arithmetic average surface roughness Ra of the mating sliding member is further smaller.
When Ra exceeds 0.1 μm, scuffing is locally formed, and the friction coefficient may be greatly improved.

Further, the counterpart sliding member that slides with the diamond sliding member is preferably an iron-based material, and the surface hardness is preferably Rockwell hardness (C scale) of HRC 45-62.
When the surface hardness of the mating sliding member is out of the above range, the mating member may be easily worn when the surface hardness is less than HRC45, and may be easily separated when the surface hardness exceeds HRC62.

Further, as a typical example of the low friction sliding mechanism of the present invention, for example, the diamond sliding member is applied to a disk-shaped shim or lifter crown surface by coating a diamond film on a base material, What applied the moving member as a cam lobe using the material which concerns on low alloy chilled cast iron, carburized steel, tempered carbon steel, and these arbitrary combinations is mentioned.
In this case, extremely low friction characteristics can be exhibited, and an excellent fuel saving effect can be exhibited.

Next, the lubricating oil composition interposed in the sliding surface in the above-described low friction sliding mechanism will be described.
Such a lubricating oil composition comprises a lubricating base oil containing one or both of a fatty acid ester-based ashless friction modifier and an aliphatic amine-based ashless friction modifier.

Here, the fatty acid ester-based ashless friction modifier and the aliphatic amine-based ashless friction modifier are 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, particularly preferably 10 to 20 carbon atoms. Mention may be made of fatty acid esters having a chain or branched hydrocarbon group, aliphatic amine compounds and any mixtures thereof.
When the number of carbon atoms is not 6 to 30, the above-described friction reduction effect may not be sufficiently obtained.

  The lubricating base oil is not particularly limited, and can be used regardless of whether it is a mineral base oil or a synthetic base oil as long as it is normally used as a base oil of a lubricating oil composition. .

  Specifically, as the mineral oil base oil, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation can be desolvated, solvent extraction, hydrocracking, solvent dewaxing, hydrorefining, Examples include those refined by performing one or more treatments such as wax isomerization, and particularly using various base oils such as those subjected to hydrocracking treatment, hydrorefining treatment or wax isomerization treatment. it can.

Specific examples of the synthetic base oil include alkyl naphthalenes, alkyl benzenes, polybutenes or hydrides thereof; poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, Diesters such as dioctyl adipate, diisodecyl adipate, ditridecyl adipate, and dioctyl sebacate; polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate These mixtures can be exemplified.
Among these, poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof are preferable examples.

  The lubricating base oil is a mixture of two or more mineral base oils or two or more synthetic base oils, in addition to using a mineral base oil or a synthetic base oil alone or in combination. There is no problem. Further, the mixing ratio of two or more kinds of base oils in the above mixture is not particularly limited and can be arbitrarily selected.

Further, the total aromatic content of the lubricating base oil is not particularly limited, but typically it is preferably 15% or less. More preferably, it is 10% or less, More preferably, it is 8%.
When the total aromatic content of the lubricating base oil exceeds 15%, the oxidation stability may be inferior.

  Furthermore, even if the total aromatic content of the lubricating base oil such as highly hydrocracked mineral oil or 1-decene oligomer hydride is 2% or less or 0%, a composition having a high friction reducing effect can be obtained. However, for example, when the content of either one or both of a fatty acid ester-based ashless friction modifier and an aliphatic amine-based ashless friction modifier exceeds 1%, storage stability may be inferior. It is desirable to adjust the total aromatic content of the lubricating base oil (for example, 2% or more) by blending solvent refined mineral oil or alkylbenzene as necessary.

  Here, the total aromatic content means an aromatic fraction content measured in accordance with ASTM D2549. Usually, this aromatic fraction includes alkylbenzene, alkylnaphthalene, anthracene, phenanthrene. And alkylated products thereof, compounds in which four or more benzene rings are condensed, or compounds having heteroaromatics such as pyridines, quinolines, phenols, naphthols, and the like.

In addition, the kinematic viscosity of the lubricating base oil is not particularly limited, but when used as a lubricating oil composition for an internal combustion engine, the kinematic viscosity at 100 ° C. is 2 mm ² / s or more and 20 mm ² / s or less. It is preferable. More preferably ^{3 mm} 2 / s or more 10 mm ² / s or less, particularly preferably in not more than ^{8 mm} 2 / s.

By setting the kinematic viscosity at 100 ° C. of the lubricating base oil to 2 mm ² / s or more, oil film formation is sufficient and the lubricity is excellent. In addition, a composition having a smaller base oil evaporation loss under high conditions can be obtained. On the other hand, by setting the kinematic viscosity at 100 ° C. to 20 mm ² / s or less, the fluid resistance becomes small, so that a composition having a smaller frictional resistance at the lubrication point can be obtained.

Further, the viscosity index of the lubricating base oil is not particularly limited, but is preferably 80 or more, for example, and preferably 100 or more when used as a lubricating oil composition for an internal combustion engine. Moreover, it is especially preferable that it is 120 or more.
As described above, by selecting a lubricant base oil having a high viscosity index, it is possible to obtain a composition that not only has excellent low-temperature viscosity characteristics but also has an excellent friction reducing effect.

On the other hand, in the lubricating oil composition, as the linear or branched hydrocarbon group having 6 to 30 carbon atoms, specifically, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, Undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group Alkyl groups such as octacosyl group, nonacosyl group and triacontyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, Octadese And alkenyl groups such as a nonacenyl group, a nonacenyl group, a hecocosenyl group, a heicocosenyl group, a dococenyl group, a tricocenyl group, a tetracocenyl group, a pentacocenyl group, a hexacocenyl group, a heptacocenyl group, an octacocenyl group, a nonacocenyl group, and a triaconenyl group. .
The alkyl group and alkenyl group include all possible linear structures and branched structures, and the position of the double bond in the alkenyl group is arbitrary.

Examples of the fatty acid ester include esters composed of a fatty acid having such a hydrocarbon group and an aliphatic monohydric alcohol or an aliphatic polyhydric alcohol.
Specific preferred examples include glycerol monooleate, glycerol diolate, sorbitan monooleate and sorbitan diolate.

Furthermore, examples of the aliphatic amine compound include an aliphatic monoamine or an alkylene oxide adduct thereof, an aliphatic polyamine, an imidazoline compound, and derivatives thereof.
Specifically, laurylamine, lauryldiethylamine, lauryldiethanolamine, dodecyldipropanolamine, palmitylamine, stearylamine, stearyltetraethylenepentamine, oleylamine, oleylpropylenediamine, oleyldiethanolamine, and N-hydroxyethyloleylimidazoline, etc. Aliphatic amine compounds, amine alkylene oxide adducts such as N, N-dipolyoxyalkylene-N-alkyl (or alkenyl) (6 to 28 carbon atoms) of these aliphatic amine compounds, carbon atoms in these aliphatic amine compounds The remaining amino group and / or a monocarboxylic acid having 2 to 30 carbon atoms (fatty acid, etc.) or a polycarboxylic acid having 2 to 30 carbon atoms such as oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc. Imi Amidated or neutralize part or all of the groups, the so-called acid-modified compounds, and the like. Preferable examples include N, N-dipolyoxyethylene-N-oleylamine.

Furthermore, the content of either one or both of the fatty acid ester-based ashless friction modifier and the aliphatic amine-based ashless friction modifier contained in the lubricating oil composition of the present invention is 0.00 on the basis of the total amount of the composition. 05 to 3.0%. The content is preferably 0.1 to 2.0%, particularly preferably 0.5 to 1.4%.
When the content is less than 0.05%, the friction reducing effect is reduced, and when it exceeds 3.0%, the solubility in lubricating oil and the storage stability are significantly deteriorated although the friction reducing effect is excellent. appear.

  The lubricating oil composition of the present invention further includes an ashless dispersant, an antiwear agent or an extreme pressure agent, a metal detergent, an antioxidant, a viscosity index improver, a friction modifier, a rust inhibitor, a nonionic agent. Various kinds of additives such as a system surfactant, a demulsifier, a metal deactivator, and an antifoaming agent can be blended singly or in combination of a plurality of kinds to enhance necessary performance.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in full detail, this invention is not limited to these Examples.

(1) Sliding member As an example of the sliding member, a pin-on-disk single-piece friction test piece as shown in FIG. 1 was produced. This unit test piece is made up of three pins and a disk, and is manufactured using a sliding member obtained by the following method. These sliding materials are shown in Table 1.

-Pin member After grinding into a predetermined pin shape from bearing steel (JIS SUJ2), the pin was finished to various surface roughnesses (Ra 0.2 μm or less) by lapping tape or barrel polishing.

・ Disk material A disk-shaped material made of silicon carbide is used to polish the sliding surface of the pin to a surface roughness of Ra 0.02 μm or less, and a pretreatment for forming a diamond film is performed. The film was coated to have various film thicknesses.
The coated surface was further polished with a wrapping tape to have various surface roughnesses of Ra 0.05 μm or less.

  For the sliding member as a comparative example, a diamond film having a rough surface was produced by changing the base formation conditions and lapping conditions. As another comparison, a disk sample on which a diamond-like carbon (DLC) film was formed by an ion plating method was also produced.

(2) Preparation of lubricating oil composition-Oil A
Hydrocracked mineral oil (100 ° C. kinematic viscosity: 5.0 mm ² / s, viscosity index: 120, total aromatic content: 5.5%) was used as the lubricating base oil, and ester friction modifier (glycerin mono) was used. Oleate) 1%, ashless dispersant (polybutenyl succinimide (nitrogen content: 1.2%)) 5.0%, calcium sulfonate as a metallic detergent (total base number: 300 mgKOH / g) , Calcium content: 12.0%) 0.5% and calcium phenate (total base number: 255 mgKOH / g, calcium content: 9.2%) 0.9%, other additives improve viscosity index A total of 7.0% of an agent, an antioxidant, a rust inhibitor, a demulsifier, a nonionic surfactant, a metal deactivator, an antifoaming agent, and the like was prepared.

・ Oil B
Similar to Oil A, except that 1-decene oligomer hydride (100 ° C. kinematic viscosity: 3.9 mm ² / s, viscosity index: 124, total aromatic content: 0.0%) was used as the lubricating base oil. The above procedure was repeated to prepare.

・ Oil C
Without adding an ester friction modifier, 1.0% of an amine friction modifier (N, N-dipolyoxyethylene-N-oleylamine) was added, and a zinc dialkyldithiophosphate (zinc content: 9.3%) , Phosphorus content: 8.5%, alkyl group: secondary butyl group or secondary hexyl group) was added in an amount equivalent to 0.047% in terms of phosphorus element, and the same operation as in oil A was repeated. Prepared.

・ Oil D
It was prepared by repeating the same operation as Oil C except that no amine friction modifier was added.
Table 2 shows the compositions and oil properties of these lubricating oil compositions (oils A to D).

(Examples 1-4)
As shown in Examples 1 to 4 of Table 1, a unit test piece in which a pin and a disk were combined was prepared, and each lubricating oil composition (oils A to D) described in each Example of Table 1 was used. A low friction sliding mechanism was constructed, and the following single friction test was conducted. The results are shown in Table 1.

(Single friction test conditions)
Test load (maximum hertz pressure): 50 kgf (690 MPa: surface pressure value between steels)
Disk rotation speed: 30 rpm
Oil supply method: Oil bath Supply oil temperature: 80 ° C
Test time: 60 min

(Comparative Examples 1-4)
Similarly, as shown in Comparative Examples 1 to 4 in Table 1, a single test piece in which a pin and a disk were combined was prepared, and each lubricating oil composition (oil A, B or A low friction sliding mechanism was constructed using D), and a single friction test similar to the above was performed. The results are shown in Table 1.

From Table 1, it can be seen that the low friction sliding mechanisms obtained in Examples 1 to 4 all exhibit an excellent low friction coefficient. For example, they have a friction reduction effect of about 20 to 60% compared to the low friction sliding mechanism of Comparative Example 4 using a combination of an iron-based material and a DLC film material used in general engines. It was.
Furthermore, from the test results of the low friction sliding mechanism obtained in Examples 1, 2, and 4, it can be seen that the smaller the zinc dithiophosphate content, the better the friction reducing effect.
In addition, the material combination of the unit test piece related to the low friction sliding mechanism obtained in Examples 1 to 4 has no problem in the surface shape after the test, is very excellent in wear resistance, and is stable and low. It showed friction characteristics.

On the other hand, in the low friction sliding mechanism obtained in Comparative Example 1, the surface roughness of the diamond member is 0.136 μm, and when the roughness is very large, the friction coefficient exceeds 0.1, resulting in friction characteristics. You can see that it is inferior. It can be inferred that this is because the surface roughness of the mating sliding surface is increased by sliding.
The low friction sliding mechanism obtained in Comparative Example 4 has a pin and disk surface roughness smaller than that of the example, but the disk is not a diamond member but a DLC film, so the friction coefficient is about 0.07. It can be seen that the friction characteristics are high and inferior.
Further, in the low friction sliding mechanism obtained in Comparative Example 2, although the surface roughness of the diamond sliding member (disk) is Ra 0.054 μm and the friction is lower than that of Comparative Example 1, the DLC film of Comparative Example 4 is used. It is about the same.
Furthermore, the low-friction sliding mechanism obtained in Comparative Example 3 has the same pin and disk configuration as in Example 1, but a lubricating oil composition containing no friction modifier used in the present invention as an oil additive ( Oil D) is used, and it can be seen that the friction coefficient is as high as about 0.07 and the friction characteristics are inferior. This can be presumed to be because a reaction film mainly composed of a friction modifier is not formed on the sliding surface.

From Examples 1 to 4, a diamond sliding member that can constitute the low friction sliding mechanism of the present invention, particularly a disk using a diamond sliding member in a suitable range, a metal material and a specific friction modifier are provided. It can be seen that when sliding under lubrication with a lubricating oil composition added in a fixed amount, a considerably low coefficient of friction is obtained and the wear resistance is excellent.
Such a significant friction reducing effect is extremely useful industrially, and is effective for greatly reducing the friction loss of engine sliding parts and the like, that is, improving the fuel consumption of the engine.

As mentioned above, although this invention was demonstrated in detail by the Example and the comparative example, this invention is not limited to these, A various deformation | transformation is possible if it is in the summary of this invention.
For example, the low friction sliding mechanism of the present invention can also be used for a gear sliding member used in industrial machines.

It is a schematic perspective view of the unit friction test method.

Explanation of symbols

1 pin 2 disc

Claims (7)

In a low friction sliding mechanism in which at least one sliding member has a sliding surface using diamond,
The arithmetic average surface roughness Ra of the sliding member using the diamond is 0.05 μm or less,
A low-friction sliding mechanism characterized in that a lubricating oil composition containing a fatty acid ester-based ashless friction modifier and / or an aliphatic amine-based ashless friction modifier is interposed on the sliding surface.   2. The low friction sliding mechanism according to claim 1, wherein the diamond sliding member is formed by coating a base material surface with a diamond film having a thickness of 0.3 to 5.0 [mu] m.   3. The low friction sliding mechanism according to claim 1, wherein an arithmetic mean surface roughness Ra of the counterpart sliding member sliding with the diamond sliding member is 0.10 μm or less.   The counterpart sliding member that slides with the diamond sliding member is an iron-based material, and the surface hardness is HRC45-62 in Rockwell hardness (C scale). The low friction sliding mechanism according to any one of the items.   The low friction sliding mechanism according to any one of claims 1 to 4, wherein the low friction sliding mechanism is used in a sliding portion of an internal combustion engine. The diamond sliding member is a disc-shaped shim or lifter crown surface in which a diamond film is coated on a base material,
The said other sliding member is a cam lobe using at least 1 sort (s) of material chosen from the group which consists of low alloy chilled cast iron, carburized steel, and tempered carbon steel, The any one of Claims 1-5 characterized by the above-mentioned. The low friction sliding mechanism according to one item. A lubricating oil composition used in the low friction sliding mechanism according to any one of claims 1 to 6,
The fatty acid ester-based ashless friction modifier and / or the aliphatic amine-based ashless friction modifier has a hydrocarbon group having 6 to 30 carbon atoms and is included in an amount of 0.05 to 3.0% based on the total amount of the composition. A lubricating oil composition characterized by comprising:

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