Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M105/00—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound
  • C10M105/02—Well-defined hydrocarbons
  • C10M105/04—Well-defined hydrocarbons aliphatic
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M125/00—Lubricating compositions characterised by the additive being an inorganic material
  • C10M125/10—Metal oxides, hydroxides, carbonates or bicarbonates
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
  • C10M159/12—Reaction products
  • C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products
  • C10M159/22—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing phenol radicals
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
  • C10M159/12—Reaction products
  • C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products
  • C10M159/24—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing sulfonic radicals
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
  • C10M169/042—Mixtures of base-materials and additives the additives being compounds of unknown or incompletely defined constitution only
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2205/00—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
  • C10M2205/02—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing acyclic monomers
  • C10M2205/028—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing acyclic monomers containing aliphatic monomers having more than four carbon atoms
  • C10M2205/0285—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing acyclic monomers containing aliphatic monomers having more than four carbon atoms used as base material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/02—Hydroxy compounds
  • C10M2207/023—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings
  • C10M2207/028—Overbased salts thereof
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/26—Overbased carboxylic acid salts
  • C10M2207/262—Overbased carboxylic acid salts derived from hydroxy substituted aromatic acids, e.g. salicylates
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
  • C10M2219/04—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions containing sulfur-to-oxygen bonds, i.e. sulfones, sulfoxides
  • C10M2219/046—Overbasedsulfonic acid salts
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2010/00—Metal present as such or in compounds
  • C10N2010/04—Groups 2 or 12
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
  • C10N2020/01—Physico-chemical properties
  • C10N2020/055—Particles related characteristics
  • C10N2020/06—Particles of special shape or size
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/02—Pour-point; Viscosity index
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/06—Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/52—Base number [TBN]
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
  • C10N2040/042—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for automatic transmissions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
  • C10N2040/045—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for continuous variable transmission [CVT]

Definitions

• the present invention relates to a transmission fluid.
• An automatic transmission is a transmission having a mechanism in which a transmission torque ratio is automatically set according to a vehicle speed, a magnitude of load and the like.
• the automatic transmission includes a torque converter, gear mechanism, hydraulic mechanism, wet clutch and the like.
• a continuously variable transmission is also often used as the transmission.
• a method of transmitting torque by friction between a metallic belt or chain and a metallic pulley is well known.
• an automobile provided with a Dual Clutch Transmission (DCT) has begun to come on the market.
• DCT Dual Clutch Transmission
• dedicated clutches are respectively prepared in an odd-numbered stage and an even-numbered stage. Since gears in a next stage are engaged in advance at gear change, gear change can be quickly done just by switching the clutches.
• Patent Literature 1 discloses a lubricating oil composition that contains a lubricating base oil, polyol compound, alkali metal borate, ashless dispersant and alkaline earth metal sulfonate. This composition can further enhance the kinematic friction coefficient ( ⁇ d) of the wet clutch (see paragraph [0073] [Advantages of the Invention]).
• Patent Literature 1 JP-A-2005-8695
• Patent Literature 1 is not always sufficient for maintaining the kinematic friction coefficient ( ⁇ d) after the longtime use of the transmission fluid.
• the transmission fluid has a complicated structure, which entails a high production cost.
• An object of the invention is to provide a transmission fluid capable of maintaining a high kinematic friction coefficient ( ⁇ d) for a long time and providing a long clutch lifetime with a simple structure.
• a transmission fluid contains: a base oil; and calcium carbonate, in which the calcium carbonate is dispersed in a form of aggregations in the transmission fluid, a ratio of the aggregations having a particle diameter of 200 nm or more is 28 mass % or less in terms of calcium based on a total amount of the aggregations, and a base value of the transmission fluid is in a range from 0.5 mgKOH/g to 3 mgKOH/g by a hydrochloric acid method.
• a transmission fluid capable of maintaining a high kinematic friction coefficient ( ⁇ d) for a long time and providing a long clutch lifetime with a simple structure can be provided.
• a transmission fluid is obtained by blending a base oil with calcium carbonate, in which the calcium carbonate is dispersed in a form of aggregations in the transmission fluid, a ratio of the aggregations having a particle diameter of 200 nm or more is 28 mass % or less in terms of calcium based on a total amount of the aggregations, and a base value of the transmission fluid is in a range from 0.5 mgKOH/g to 3 mgKOH/g by a hydrochloric acid method.
• the transmission fluid of the invention (hereinafter, also referred to as “the present transmission fluid”) will be described in detail below.
• the transmission fluid obtained by blending a base oil and calcium carbonate means not only a transmission fluid containing the base oil and calcium carbonate, but also a composition containing a modified substance obtained by modifying at least one of the base oil and calcium carbonate, and a composition containing a reactant obtained by reaction of the base oil and/or calcium carbonate.
• the base oil usable in the present transmission fluid is not particularly limited, but may be at least one of the mineral oil and the synthetic oil.
• the base oil may be one or a plurality of the mineral oil, one or a plurality of the synthetic oil, or a combination of the mineral oil and the synthetic oil.
• the mineral oil and the synthetic oil are not specifically limited, but any mineral and any synthetic oil generally usable as a base oil for a transmission are suitable.
• the base oil having a kinematic viscosity at 100 degrees C. in a range from 1 mm 2 /S to 50 mm 2 /s, particularly from 2 mm 2 /s to 15 mm 2 /s is preferably usable.
• the kinematic viscosity at 100 degrees of the base oil is 1 mm 2 /s or more, an increase in abrasion at a sliding portion such as a gear bearing and a clutch of the transmission is restrained.
• the kinematic viscosity at 100 degrees of the base oil is 50 mm 2 /s or less, deterioration of a low-temperature viscosity is expected to be restrained.
• a pour point of the base oil which is an index of a low-temperature fluidity, is not particularly limited, but is preferably minus 10 degrees C. or less, particularly preferably minus 15 degrees C. or less.
• the base oil preferably has a saturated hydrocarbon component of 90 mass % or more, a sulfur content of 0.03 mass % or less and a viscosity index of 100 or more.
• the saturated hydrocarbon component is 90 mass % or more, an amount of deteriorated products is reducible.
• the sulfur content is 0.03 mass % or less, an amount of deteriorated products is reducible.
• the viscosity index of the base oil is 100 or more, abrasion at a high temperature is reducible.
• Examples of the mineral oil include a naphthenic mineral oil, a paraffinic mineral oil and GTL WAX. Specific examples of the mineral oil include light neutral oil, intermediate neutral oil, heavy neutral oil, and bright stock, which are obtainable by solvent purification or hydrogenation purification.
• examples of the synthetic oil include polybutene, a hydride thereof, polyalphaolefin (e.g., 1-octene oligomer, 1-decene oligomer), alkylbenzene, polyolester, diacid ester, polyoxyalkyleneglycol, polyoxyalkyleneglycolester, polyoxyalkyleneglycolether, hindered ester and silicone oil.
• polyalphaolefin e.g., 1-octene oligomer, 1-decene oligomer
• alkylbenzene e.g., 1-octene oligomer, 1-decene oligomer
• alkylbenzene e.g., 1-octene oligomer, 1-decene oligomer
• alkylbenzene e.g., 1-octene oligomer, 1-decene oligomer
• alkylbenzene e.g
• PAO polyalphaolefin
• examples of PAO include alphaolefin homopolymers and alphaolefin copolymers.
• a ratio of PAO is preferably 30 mass % or more in the base oil, preferably 50 mass % or more.
• a kinematic viscosity at 100 degrees C. of PAO is preferably in a range from 2 mm 2 /s to 200 mm 2 /s.
• the present transmission fluid contains calcium carbonate in a specific form (hereinafter, also referred to as “the present calcium carbonate”).
• the present calcium carbonate is dispersed in a form of aggregations in the transmission fluid.
• a ratio of an aggregation having a particle diameter of 200 nm or more (hereinafter, also referred to as a “large particle”) is 28 mass % or less in terms of calcium based on a total amount of the aggregations, preferably 25 mass % or less.
• a resultant transmission fluid can maintain a high kinematic friction coefficient ( ⁇ d) for a long time.
• An average particle diameter of the above aggregations is preferably in a range from 1 nm to 180 nm, more preferably from 10 nm to 150 nm in order to efficiently achieve the advantages of the invention.
• the particle diameter, a particle-diameter distribution and the average particle diameter of the above aggregations are measurable according to electrophoretic light scattering.
• a particle-diameter measurement system using ELSZ-1000S manufactured by Otsuka Electronics Co., Ltd. is suitably usable.
• the base oil or any transmission fluid may be blended with calcium carbonate having an aggregations with a predetermined particle size distribution or may be blended with an overbased organic acid calcium salt compound including a predetermined aggregation (e.g., an overbased detergent).
• the present calcium carbonate is derived from the overbased organic acid calcium salt compound.
• a manufacturing method of calcium carbonate (aggregations) is not particularly limited, but, for instance, may include neutralizing an organic acid with basic calcium oxide and hydroxide and subsequently carbonating excessive basic calcium oxide and hydroxide.
• a content of the present calcium carbonate is preferably in a range from 0.001 mass % to 0.3 mass % in terms of calcium based on a total amount of the present transmission fluid, more preferably from 0.001 mass % to 0.2 mass %, further preferably from 0.01 mass % to 0.2 mass %.
• a high kinematic friction coefficient ( ⁇ d) can be maintained for a long time.
• the ratio of the large particles in the present transmission fluid is preferably 0.056 mass % or less in terms of calcium based on the total amount of the present transmission fluid, more preferably from 0.045 mass % or less.
• a high kinematic friction coefficient ( ⁇ d) can be maintained for a long time.
• the overbased detergent is preferably at least one of a sulfonate detergent, a salicylate detergent and a phenate detergent in order to efficiently achieve the advantages of the invention.
• a base value of the present transmission oil is in a range from 0.5 mgKOH/g to 3 mgKOH/g by a hydrochloric acid method (JIS K2501), more preferably in a range from 0.7 mgKOH/g to 2.8 mgKOH/g.
• JIS K2501 hydrochloric acid method
• ⁇ d kinematic friction coefficient
• the overbased organic acid calcium salt compound itself only needs to contain calcium carbonate and be overbased.
• the base value of the overbased organic acid calcium salt compound is not particularly limited, but a total base value thereof is preferably in a range from 10 mgKOH/g to 400 mgKOH/g by the hydrochloric acid method (JIS K2501).
• the present transmission fluid preferably has the kinematic viscosity at 100 degrees C. in a range from 3 mm 2 /s to 8 mm 2 /s, more preferably in a range from 4 mm 2 /s to 7 mm 2 /s in order to efficiently achieve the advantages of the invention.
• a viscosity index of the present transmission fluid is preferably 100 or more.
• the present transmission fluid can contain various additives as long as an object of the invention is not hampered.
• the additives usable as needed include a viscosity index improver, an antioxidant, a antiwear agent, a friction modifier, an ashless dispersant, a metal deactivator, a rust inhibitor an antifoaming agent, a pour point depressant, a surfactant and a coloring agent.
• viscosity index improver examples include polymethacrylate, dispersed polymethacrylate, olefin copolymer (e.g. ethylene-propylene copolymer), dispersed olefin copolymer and styrene copolymer (e.g. styrene-diene copolymer and styrene-isoprene copolymer).
• a content of the viscosity index improver is approximately in a range from 0.5 mass % to 15 mass % of the total amount of the present transmission fluid in view of the blending effect thereof.
• An example of the pour point depressant is polymethacrylate having a mass average molecular weight of 10000 to 150000.
• a preferable content of the pour point depressant is approximately in a range from 0.01 mass % to 10 mass % of the total amount of the present transmission fluid.
• antioxidant examples include an aminic antioxidant, a phenolic antioxidant and a sulfuric antioxidant.
• Examples of the aminic antioxidant may include monoalkyldiphenylamine compounds such as monooctyldiphenylamine and monononyldiphenylamine; dialkyldiphenylamine compounds such as 4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine, 4,4′-dihexyldiphenylamine, 4,4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine and 4,4′-dinonyldiphenylamine; polyalkyldiphenylamine compounds such as tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine and tetranonyldiphenylamine; and naphthylamine compounds such as alpha-naphthylamine, phenyl-alpha-naphthylamine, but
• phenolic antioxidant may include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 4,4′-methylenebis(2,6-di-t-butylphenol), 4,4′-butylidenebis(3-methyl-6-t-butylphenol), 2,2′-methylenebis(4-ethyl-6-t-butylphenol), 2,2′-methylenebis(4-methyl-6-t-butylphenol), 4,4′-isopropylidene bisphenol, 2,4-dimethyl-6-t-butylphenol, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, 1,1,3-tris(2-methyl-4-hydroxy5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,
• sulfuric antioxidant may include dialkylthiodipropionate, dialkylthiocarbamic acid derivative (except for a metal salt), bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide, mercaptobenzothiazole, a reactant of phosphorus pentasulfide and an olefin, and dicetyl sulfide.
• One of various antioxidants as described above may be used alone or two or more thereof may be used in combination.
• the aminic antioxidant, the phenolic antioxidant or zinc alkyldithio phosphate is preferably used.
• a preferable content of the antioxidant is approximately in a range from 0.05 mass % to 3 mass % of the total amount of the present transmission fluid.
• the antiwear agent may include a thiophosphoric acid metal salt (e.g., Zn, Pb and Sb), a thiocarbamic acid metal salt (e.g., Zn), a sulfur compound, phosphate ester (tricresyl phosphate) and phosphite ester.
• a preferable content of the antiwear agent is approximately in a range from 0.05 mass % to 5 mass % of the total amount of the present transmission fluid.
• Examples of the friction modifier may include a polyhydric alcohol partial ester such as neopentyl glycol monolaurate, trimethyrol propanemonolaurate, glycerin monooleate (oleic acid monoglyceride).
• a preferable content of the friction modifier is approximately in a range from 0.05 mass % to 4 mass % of the total amount of the present transmission fluid.
• Examples of the ashless dispersant may include succinimides, boron-containing succinimides, benzylamines, boron-containing benzylamines, succinic acid esters, and mono- or di-carboxylic acid amides respectively represented by a fatty acid or succinic acid.
• a preferable content of the ashless dispersant is approximately in a range from 0.1 mass % to 20 mass % of the total amount of the present transmission fluid.
• One of the metal deactivators such as benzotriazole and thiadiazole may be used alone or two or more thereof may be used in a combination.
• a preferable content of the metal deactivator is approximately in a range from 0.01 mass % to 5 mass % of the total amount of the present transmission fluid.
• the rust inhibitor may include a fatty acid, alkenylsuccinic acid half ester, fatty acid soap, alkyl sulfonate, fatty acid ester of polyhydric alcohol, fatty acid amide, oxidized paraffin and alkyl polyoxyethylene ether.
• a preferable content of the rust inhibitor is approximately in a range from 0.01 mass % to 3 mass % of the total amount of the present transmission fluid.
• One of the antifoaming agents such as a silicone compound and an ester compound may be used alone or two or more thereof may be used in a combination.
• a preferable content of the antifoaming agent is approximately in a range from 0.05 mass % to 5 mass % of the total amount of the present transmission fluid.
• the pour point depressant is exemplified by polymethacrylate.
• a preferable content of the pour point depressant is approximately in a range from 0.01 mass % to 10 mass % of the total amount of the present transmission fluid.
• the surfactant is exemplified by polyoxyethylene alkyl phenyl ether.
• a preferable content of the surfactant is approximately in a range from 0.01 mass % to 10 mass % of the total amount of the present transmission fluid.
• the present transmission fluid as described above provides a long clutch lifetime since the present transmission fluid can maintain a high kinematic friction coefficient ( ⁇ d) for a long time, and is suitably applicable to various transmissions such as an automatic transmission (AT), a continuously variable transmission (CV) and a dual clutch (DCT).
• AT automatic transmission
• CV continuously variable transmission
• DCT dual clutch
• PAO a kinematic viscosity at 100 degrees C. of 4.0 mm 2 /s
• An overbased calcium sulfonate having properties shown in Table 1 was blended at 0.15 mass % in terms of calcium based on a total amount of each of the sample oils to prepare sample oils respectively having properties shown in Table 1 (all the sample oils are intended to be used for the transmission).
• the viscosity index of each of the sample oils in Example 1 and Comparatives 1 and 2 was 120.
• the overbased calcium was dispersed in the base oil and checked in terms of a structure of the aggregations. Specifically, a dispersed state of the aggregations (including large particles) in each of the sample oils was measured by ELSZ-1000S manufactured by Otsuka Electronics Co., Ltd. A ratio (mass % relative to the aggregations) of the large particles in the aggregations formed of calcium carbonate and an average particle diameter of each of the large particles were calculated. The results are shown in Table 1. Average particle diameters of the sample oils were respectively 100 nm in Example 1, 200 nm in Comparative 1 and 800 nm in Comparative 2.
• Material a cellulose clutch material used in an actual transmission
• the sample oil of Example 1 containing substantially no large particle can maintain a high kinematic friction coefficient ( ⁇ d) for a long time and provide a long clutch lifetime (shudder lifetime).
• ⁇ d kinematic friction coefficient
• Comparatives 1 and 2 having a lot of large particles although the sample oils having an approximately equivalent content of overbased calcium sulfonate and an approximately equivalent base value, the kinematic friction coefficient ( ⁇ d) is significantly decreased approximately after the elapse of 72 hours after the test starts. Accordingly, it is understood that the decrease in the large particles in the transmission fluid is crucial.

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• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Lubricants (AREA)

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• 2014
  • 2014-09-08 US US14/913,866 patent/US20160208192A1/en not_active Abandoned
  • 2014-09-08 WO PCT/JP2014/073694 patent/WO2015034090A1/ja active Application Filing
  • 2014-09-08 EP EP14842902.0A patent/EP3034584A4/en not_active Withdrawn
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