JPH07268375A - Lubricating oil composition for automatic speed change gear - Google Patents

Abstract

PURPOSE:To obtain a lubricating oil composition for automatic speed change gears, excellent in shudder preventing performances in the initial period to a long period without deteriorating the torque transmission capacity and especially suitable as a lubricating oil for the automatic speed change gears for automobiles equipped with a slip controlling mechanism. CONSTITUTION:This lubricating oil composition for automatic speed change gears contains (A) at least one compound selected from the group consisting of zinc dithiophosphate and basic zinc dithiophosphate in an amount of 0.05-5wt.% based on the total amount of the composition, (B) at least one compound selected from the group consisting of an alkaline earth metallic sulfonate having at least one >=8C alkyl group, phenates, salicylates and perbasic salts thereof in an amount of 0.05-5wt.% based on the total amount of the composition and (C) at least one compound selected from the group consisting of phosphoric esters, acid phosphoric esters, phosphorous esters and acid phosphorous esters in an amount of 0.01-5 wt.% based on the total composition in a base oil comprising a mineral oil and/or a synthetic oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil composition for an automatic transmission, and more particularly, to a lubricating oil for an automatic transmission which is excellent in shudder prevention performance for an initial period and a long period without lowering torque transmission capacity. It relates to a composition.

[0002]

2. Description of the Related Art Automatic transmission oil (Automatic T
transmission fluid; abbreviated as ATF)
Is a lubricating oil used in an automatic transmission (AT) of an automobile that incorporates a torque converter, a gear mechanism, a hydraulic mechanism, a wet clutch, and the like. In order to operate the automatic transmission smoothly, the ATF includes a torque converter, a hydraulic system, a power transmission medium in a control system, gears and bearings, lubrication of a wet clutch, a heat medium for temperature adjustment, lubrication of friction materials, and proper lubrication. It is required to have many functions such as maintaining good friction characteristics. ATF is required to cope with severe operating conditions and extension of refueling period due to higher performance such as higher speed and higher output of automobiles. Especially, new converter clutch shudder ( Measures against shudder (abnormal vehicle body vibration) have become an important technical issue.

In recent years, lock-up clutches that are effective in improving fuel consumption have been adopted in ATs for many automobiles. By providing a lock-up mechanism and switching between torque converter drive and direct drive at an appropriate time, the efficiency of the torque converter can be improved. The function of the lockup clutch is to transmit the driving force of the engine directly to the transmission according to the running condition. Conventionally, the lockup mechanism operates only in the high speed range and has not been used in the low speed range.Therefore, in the low speed range such as when the vehicle starts, when the torque is transmitted by the torque converter, the engine output speed and the transmission input speed are transmitted. This caused power transmission loss with the number, which was a cause of reduced fuel consumption. In order to reduce this power transmission loss, recently, a lockup mechanism has been operated even in a low speed range of an automatic transmission.

That is, for the purpose of improving fuel economy, slip control in which a lockup clutch built in the torque converter is used even in a low speed range is being introduced.
However, the automatic transmission with the lock-up clutch may generate a shudder when the lock-up operation is performed. This shudder frequently occurs when the lockup mechanism is operated in the low speed range of the automatic transmission. Particularly, in a slip control type lock-up clutch in which the difference between the engine speed and the output speed of the torque converter has a specific value so as to prevent the torque fluctuation of the engine from being transmitted to the chassis, shudder is likely to occur.

In the slip control type lock-up clutch, shudder is likely to occur when the friction coefficient increases as the relative slip speed decreases. Therefore,
In order to prevent the occurrence of shudder, the ATF is required to have excellent low-speed sliding performance, that is, a friction characteristic and a high torque capacity (high friction coefficient) such that the friction coefficient becomes higher as the sliding speed increases. . Moreover, such frictional characteristics must be stable for a long period of time before the mechanical parts (especially friction material) used in the automatic transmission are adapted to the ATF and before the mileage of the vehicle reaches 100,000 km or more. I have to. However, the conventional ATF lacks good friction characteristics of μ (friction coefficient) -V (sliding speed) characteristics, and as an automatic transmission lubricating oil with a slip control mechanism,
The anti-shudder performance and its durability are still insufficient.

[0006] Conventionally, for example, in Japanese Patent Laid-Open No. 62-84190, by adding magnesium sulfonate to a lubricating base oil, the durability of shift gear shifting and the prevention of shift feeling are improved and friction is improved. It has been proposed to prevent the coefficient from changing with time. Further, this publication describes adding a phosphoric acid ester, an acidic phosphoric acid ester, and zinc dithiophosphate (ZnDTP), which are added to ordinary lubricating oils. However, the ATF having the additive composition described in the publication still has a problem in terms of anti-shudder performance.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent anti-shudder performance for an initial period and a long period of time, including before smoothing the friction material of the clutch portion of an automatic transmission, without lowering the torque transmission capacity. An object of the present invention is to provide a lubricating oil composition for an automatic transmission, which is suitable as a lubricating oil for an automatic transmission of an automobile equipped with a slip control mechanism. The present inventor has conducted extensive studies to overcome the problems of the prior art, and as a result, the lubricating base oil has zinc dithiophosphate and / or basic zinc dithiophosphate, sulfonates of alkaline earth metals, phenates and salicylates. And at least one compound selected from the group consisting of these overbased salts, and at least one compound selected from the group of phosphoric acid ester, acidic phosphoric acid ester and phosphorous acid ester as an essential component As a result, the distance traveled by the vehicle can be reduced to 1 before the mechanical parts used in the automatic transmission are fitted.
It was found that a lubricating oil composition exhibiting excellent anti-shudder performance and having a high torque capacity can be obtained for a long period of time up to 0,000 km or more, and based on this finding, the present invention has been completed. .

[0008]

According to the present invention, a base oil consisting of a mineral oil and / or a synthetic oil is added, based on the total weight of the composition, from (A) zinc dithiophosphate and basic zinc dithiophosphate. 0.05 to 5% by weight of at least one compound selected from the group consisting of (B) sulfonates, phenates, salicylates of alkaline earth metals having at least one alkyl group having 8 or more carbon atoms, and overbased salts thereof. 0.05 to 5% by weight of at least one compound selected from the group consisting of, and (C) at least one selected from the group consisting of phosphoric acid ester, acidic phosphoric acid ester, phosphorous acid ester, and acidic phosphorous acid ester. There is provided a lubricating oil composition for an automatic transmission, which comprises 0.01 to 5% by weight of the compound. Further, according to the present invention, the following preferred embodiments (1) to (6) of the invention are provided. (1) Zinc dithiophosphate has the general formula (a)

[0009]

[Chemical 1]

(Wherein R ¹ , R ² , R ³ and R ⁴ are independently a hydrocarbon group having 1 to 20 carbon atoms and may be the same or different). And alkaline earth metal sulfonates, phenates and salicylates are represented by the following general formulas (b), (c) and (d), respectively:

[0011]

[Chemical 2]

[0012]

[Chemical 3]

[0013]

[Chemical 4]

[In the formulas (a), (b) and (c), R ⁵ ,
R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms and may be the same or different, but at least one of them is an alkyl group having 8 or more carbon atoms. It is a base. Me is calcium or magnesium. X is an integer of 1 to 3. ] And a phosphoric acid ester, an acidic phosphoric acid ester, a phosphorous acid ester, and an acidic phosphorous acid ester are represented by the following general formulas (e), (f), and (g), respectively.

[0015]

[Chemical 5]

[0016]

[Chemical 6]

[0017]

[Chemical 7]

[In the formulas (e), (f) and (g), R
⁹ is a hydrocarbon group having 1 to 30 carbon atoms or a sulfur atom-containing hydrocarbon group. X is 1, 2 or 3. Y
Is 1 or 2. ] The lubricating oil composition for automatic transmissions, which is a compound represented by:

(2) In the general formula (a), R ¹ , R ² ,
R ³ and R ⁴ are each independently an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a cycloalkyl group having 6 to 18 carbon atoms, an arylalkyl group, or an alkylaryl group. A lubricating oil composition for an automatic transmission according to item 1). (3) In the general formulas (b), (c) and (d),
R ⁵ , R ⁶ , R ^7, and R ⁸ are each independently an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, and 6 carbon atoms.
18. The automatic transmission lubricating oil composition according to item (1), which is a cycloalkyl group, an arylalkyl group or an alkylaryl group.

(4) In the general formulas (e), (f) and (g), R ⁹ is an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or a cycloalkyl having 6 to 20 carbon atoms. The lubricating oil composition for an automatic transmission according to item (1), which is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group. (5) The lubricating oil composition for an automatic transmission, wherein the basic zinc dithiophosphate is a basic zinc dithiophosphate corresponding to the general formula (a). (6) The alkaline earth metal sulfonates, phenates, and salicylate overbased salts have the general formula (b):
The lubricating oil composition for an automatic transmission, which is an overbased salt of the compounds represented by (c) and (d). Hereinafter, the present invention will be described in detail.

[0021] As the base oil base oil automatic transmission lubricating oil composition may be used any of mineral oils and synthetic oils. As mineral oil, solvent-refined raffinate obtained by treating a lubricating oil raw material derived from crude oil by atmospheric distillation or reduced pressure distillation with an aromatic extraction solvent such as phenol, furfural, or N-methylpyrrolidone; Hydrotreated oil obtained by contacting with hydrogen under hydrotreating conditions in the presence of a catalyst for use, or a mixed oil of these or a lubricating oil fraction obtained by combining a solvent refining step and a hydrotreating step, etc. Can be mentioned. According to any of the manufacturing methods, the dewaxing step, the hydrofinishing step, the clay treatment step and the like can be arbitrarily adopted in accordance with a conventional method. Specific examples of the mineral oil include light neutral oil, medium neutral oil, heavy neutral oil, bright stock and the like, which can be prepared by appropriately mixing so as to satisfy the required properties.

Examples of the synthetic oil include poly α-olefin, α-olefin copolymer, polybutene, alkylbenzene, polyol ester, dibasic acid ester,
Examples thereof include polyoxyalkylene glycol, polyoxyalkylene glycol ester or polyoxyalkylene glycol ether, and silicone oil.

These base oils may be used alone or in combination of two or more, and mineral oil and synthetic oil may be used in combination. The base oil used in the present invention, at 100 ° C., usually, 3 to 20 mm ² /
s kinematic viscosity of 4 to 15 mm ² /
The range is s. If the kinematic viscosity of the base oil is too high, the low temperature viscosity will deteriorate, and conversely, if it is too low, the gear bearing of the automatic transmission,
It has a drawback that wear is increased in sliding parts such as clutches.

Component (A) , zinc dithiophosphate, has the general formula (a)

[0025]

[Chemical 8] In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, which may be the same or different.

The preferred hydrocarbon group has 1 to 1 carbon atoms.
Examples thereof include an alkyl group having 18 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group or an arylalkyl group. Particularly preferred hydrocarbon groups include alkyl groups and alkenyl groups, which are linear or branched, and preferably have 5 to 18 carbon atoms.
Therefore, the particularly preferred carbon number is 6 to 13.

The zinc dithiophosphate is contained in an amount of 0.05 to 5% by weight, preferably 0.1% by weight, based on the total weight of the composition, based on the base oil.
It is added in a proportion of 07 to 1% by weight. A particularly suitable amount of addition is in the range of 0.1 to 0.5% by weight.

In the present invention, a basic zinc dithiophosphate obtained by incorporating zinc oxide into zinc dithiophosphate can be used. Basic zinc dithiophosphate is
Those containing 0 to 50 mol% as ZnO can be used. As the basic zinc dithiophosphate, a commercially available product such as that manufactured by Amoco can be used.

The component (B), an alkaline earth metal sulfonate, is an alkali metal salt of petroleum sulfonic acid or a sulfonic acid of a long-chain alkylbenzene or alkylnaphthalene, and in the present invention, it has the general formula (b):

[0030]

[Chemical 9] Includes those represented by. In formula (b), R ⁵ and R ⁶
Are each independently a hydrocarbon group having 1 to 30 carbon atoms and may be the same or different. However, at least one of the hydrocarbon groups is an alkyl group having 8 or more carbon atoms.
Me is calcium or magnesium.

Preferred hydrocarbon groups have 1 to 1 carbon atoms.
Examples thereof include an alkyl group having 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cycloalkali group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, and an arylalkyl group. A particularly preferred hydrocarbon group is a linear or branched alkyl group or alkenyl group having 8 to 18 carbon atoms. In the present invention, an overbased sulfonate can be used and exhibits a remarkable effect in terms of anti-shudder performance. Overbased salts are hydroxides [M
e (OH) ₂ ] or carbonate [MeCO ₃ ] is colloidally dispersed in the above-mentioned sulfonate, and a base number of 0 to 400 mgKOH / g can be used in the present invention.

The alkaline earth metal sulfonate is added to the base oil in a proportion of 0.05 to 5% by weight, preferably 0.07 to 3% by weight, based on the total weight of the composition. A particularly preferred amount of addition is in the range of 0.1 to 1% by weight. Alkaline earth metal phenates are represented by the alkaline earth metal salts of sulfurized alkylphenols and have the general formula (c)

[0033]

[Chemical 10]

Includes those represented by Formula (c)
Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently have 1 to 3 carbon atoms.
It is a hydrocarbon group of 0 and may be the same or different. However, at least one of the hydrocarbon groups has 8 carbon atoms.
The above alkyl groups. Me is calcium or magnesium. X is an integer of 1 to 3. Preferred hydrocarbon groups are the same as those described above for the sulfonate, and particularly preferred hydrocarbon groups are linear or branched alkyl or alkenyl groups having 8 to 18 carbon atoms.

The overbased phenate is prepared by adding hydroxide [Me (OH) ₂ ] or carbonate [MeCO ₃ ] to the above phenate.
Is 0 to 50 mol% expressed as MeCO ₃ and has a base number of 0 to 4
It is the one of 00 mgKOH / g. The alkaline earth metal phenate is based on the total weight of the composition, relative to the base oil,
It is added in a proportion of 0.05 to 5% by weight, preferably 0.07 to 3% by weight. Particularly preferred addition amount is 0.1 to 1
It is in the range of% by weight. Alkaline earth metal salicylates have the general formula (d)

[0036]

[Chemical 11]

Includes those represented by Formula (d)
In the above, R ⁵ and R ⁶ are each independently a hydrocarbon group having 1 to 30 carbon atoms and may be the same or different. However, at least one of the hydrocarbon groups is an alkyl group having 8 or more carbon atoms. Me is calcium or magnesium. Overbased salicylate is a carbonate dispersed in the above salicylate in a colloidal form.
_The content of ₃ is 0 to 50 mol%. The alkali metal salicylate is added to the base oil in a proportion of 0.05 to 5% by weight, preferably 0.07 to 3% by weight, based on the total weight of the composition. A particularly preferable amount of addition is 0.
It is in the range of 1 to 1% by weight.

The phosphorus compounds such as the phosphoric acid ester, the acidic phosphoric acid ester and the phosphorous acid ester as the component (C) include those represented by the general formulas (e), (f) and (g). .

[0039]

[Chemical 12]

[0040]

[Chemical 13]

[0041]

[Chemical 14]

In the above formula, R ⁹ is a hydrocarbon group having 1 to 30 carbon atoms or a sulfur atom-containing hydrocarbon group, which may be the same or different in each formula. X
Is 1, 2 or 3. Y is 1 or 2.
A preferred hydrocarbon group is an alkyl group having 1 to 20 carbon atoms,
An alkenyl group having 2 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, and an arylalkyl group. A particularly suitable hydrocarbon group is a linear or branched alkyl group having 8 or more carbon atoms.

Specific examples of the phosphoric acid ester include triaryl phosphate and the like. Examples thereof include benzyl diphenyl phosphate, allyl diphenyl phosphate, and the like.
Triphenyl phosphate, tricresyl phosphate, ethyl diphenyl phosphate, tributyl phosphate, dibutyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate, diethyl phenyl phenyl phosphate, propyl phenyl diphenyl phosphate, dipropyl phenyl phenyl phosphate,
Compounds such as triethylphenyl phosphate, tripropylphenyl phosphate, butylphenyldiphenylphosphate, dibutylphenylphenylphosphate, tributylphenylphosphate, propylphenylphenylphosphate mixture, butylphenylphenylphosphate mixture and the like can be mentioned.

As the acidic phosphoric acid ester, for example, 2
-Ethylhexyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate,
Tridecyl acid phosphate, stearyl acid phosphate, isostearyl amid phosphate,
Examples thereof include oleyl acid phosphate and di-2-ethylhexyl phosphate.

Examples of the phosphite include triphenylphosphite, tri (p-cresyl) phosphite, tris (nonylphenyl) phosphite, triisooctylphosphite, diphenylisodecylphosphite, phenylisodecylphosphite. Examples include phyto, triisodecyl phosphite, tristearyl phosphite, and trioleyl phosphite.

Examples of the acidic phosphite include:
Di-2-ethylhexyl hydrogen phosphite,
Examples thereof include dilauryl hydrogen phosphite and dioleyl hydrogen phosphite. Examples of the sulfur atom-containing hydrocarbon group include a dodecylthioethyl group. The phosphorus compound is 0.01 to 5% by weight, preferably 0.0 to 5% by weight based on the total weight of the composition, based on the base oil.
It is added in a proportion of 3 to 3% by weight. A particularly preferable amount of addition is in the range of 0.05 to 1% by weight.

The metallic detergent as the component (B) is a compound which is thermally stable and has a strong structure against shearing force.
By using a metal-based detergent having a long hydrocarbon group as a friction modifier, an ATF having a long life can be obtained. Further, by using the ZnDTP and / or the basic ZnDTP of the component (A) together, these components immediately form a reaction film on the metal surface before the leveling, and the metal surface is as if after the leveling. Since it becomes a smooth surface,
It is possible to obtain the same good friction characteristics as those after the smoothing from the initial state before the smoothing. In addition to these combinations,
The addition of the anti-wear agent as the component (C) is essential for constituting the minimum required composition as the ATF.

The lubricating oil composition for an automatic transmission of the present invention comprises
If necessary, viscosity index improver, ashless dispersant, antioxidant, extreme pressure agent, metal deactivator, pour point depressant, antifoaming agent,
Corrosion inhibitors and the like can be added as appropriate. As the viscosity index improver, for example, polymethacrylate-based, polyisobutylene-based, ethylene-propylene copolymer-based, styrene-butadiene hydrogenated copolymer and the like can be used, and these are usually 3 to 35% by weight. Used in proportion. Examples of the ashless dispersant include, for example, polybutenyl succinimide type, polybutenyl succinamide type, benzylamine type, and ester type, and these are usually
It is used in a proportion of 0.05 to 7% by weight.

Examples of the antioxidant include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine and alkylated-α-naphthylamine, 2,6-ditertiarybutylphenol, 4,
Examples thereof include phenolic antioxidants such as 4'-methylenebis- (2,6-ditertiarybutylphenol), and these are usually used in a proportion of 0.05 to 2% by weight. Examples of the extreme pressure agent include dibenzyl sulfide, dibutyl disulfide and the like, and these are usually added in a proportion of 0.05 to 3% by weight.

Examples of the metal deactivator include benzotriazole, thiadiazole and the like, and these are usually added in a proportion of 0.01 to 3% by weight. Examples of the pour point depressant include ethylene-vinyl acetate copolymer, a condensate of chlorinated paraffin and naphthalene, a condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkylstyrene, and the like. Usually, it is used in a proportion of 0.1 to 10% by weight.

[0051]

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

Various performance measuring methods in Examples (1) Leveling before shudder prevention performance As a testing machine, LVFA (Low Velocity F)
Ricture Apparatus) was used to measure the pre-shudder prevention performance in the following manner. The ratio of μ _H / μ _L was used as the criterion.・ Testing machine: LVFA ・ Friction material: SD1777 ・ Oil temperature: 80 ℃ ・ Amount of oil: 100 cc ・ Surface pressure: 10 kgf / cm ²・ Judgment standard: μ _H / μ _L μ _H・ ・ ・ Relative slip speed 1.0 m / Friction coefficient at s μ _L ... If the friction coefficient at a relative slip speed of 0.5 m / s is μ _H / μ _L > 1, no shudder is generated in the actual machine.

(2) Anti-shudder performance life ・ Testing machine: LVFA ・ Criteria: Durability evaluation by continuous slip is performed, and μ _H / μ _L is measured at regular intervals based on the above method of pre-shudder anti-shudder performance. Then, the time until μ _H / μ _L ≦ 1 is used as an index. The longer the time, the longer the anti-shudder performance. [Continuous Slip Durability Evaluation conditions] · Friction material: SD1777-oil volume: 100 cc, oil temperature: 0.99 ° C.-surface pressure: 10 kgf / cm ² · relative slip speed: 1.0 m / s Continuous Slip

(3) Torque capacity Testing machine: SAE No. 2 ・ Friction material: SD1777, 3 sheets ・ Amount of oil: 800 cc ・ Oil temperature: 100 ° C ・ Surface pressure: 8 kgf / cm ²

[Dynamic test] The friction material was rotated at 3 revolutions.
Unloaded rotation is performed at 600 rpm and an inertia weight of 3.5 kgf · cm · s ² , and pressure is applied so that the friction material is sandwiched between steel plates, and rotation is stopped. [Static test] A pressure is applied so that the friction material is sandwiched between steel plates, the friction material is rotated at a rotation speed of 0.72 rpm, and the rotational torque generated at that time is read and converted into a friction coefficient. Measure the friction coefficient μ _s at the maximum torque that slides at low speed.

Example 1 Solvent refined mineral oil (1
With a kinematic viscosity of 4 mm ² / s at 00 ° C., zinc dithiophosphate, di-2-ethylhexyl zinc dithiophosphate, 0.3
% By weight, 0.3% by weight of calcium sulfonate as a metal detergent, 0.1% by weight of 2-ethylhexyl acid phosphate as an S / P antiwear agent, and further polymethacrylate (viscosity index improver). 5% by weight, polybutenyl succinimide (ashless detergent dispersant) 4
% By weight, alkyldiphenylamine (antioxidant) 0.
5% by weight, dibenzyl sulfide (extreme pressure agent) 0.2% by weight, and benzotriazole (metal deactivator) 0.
05 wt% was added to obtain a lubricating oil composition for an automatic transmission.

SAE No. as the anti-shudder performance index, anti-shudder performance life index and torque capacity of the lubricating composition for automatic transmission obtained here. When μ _s (100 ° C.) at 250 c / c was obtained, the following results were obtained. Shader prevention performance index: 1.14 Shader prevention performance life index: 10 SAE No. Μ _s [100 ° C.] at 250 c / c: 0.13

[Examples 2 to 21, Comparative Examples 1 to 8] Tables 1 to 1
According to 5, each component was used to prepare an automatic transmission oil lubricating oil composition. The anti-shudder performance and torque capacity of each composition were determined in the same manner as in Example 1, and the results are shown in Tables 1-5.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

[0063]

[Table 5]

(Footnote) (1) Mineral oil: Solvent refined mineral oil (Kinematic viscosity at 100 ° C. 4 mm
² / s) (2) Synthetic base oil: poly α-olefin (kinematic viscosity at 100 ° C. is 4 mm ² / s) (3) R1, R6, R8 and R18 are the carbon number of the alkyl group in each compound. Show. (4) * 1: Basic zinc dithiophosphate (ZnO 15 mol%) (5) * 2: Overbased Ca sulfonate (carbonate; base number 300 mgKOH / g) (6) * 3: Sulfur atom-containing alkyl group ( Dodecylthioethyl group)

As is clear from these tables, the lubricating oil composition of the present invention has a good anti-shudder performance index,
In addition to excellent anti-shudder performance during break-in operation, the anti-shudder life index is also remarkably excellent, providing excellent anti-shudder performance life. Moreover, the lubricating oil composition of the present invention has a sufficient torque capacity.

[0066]

The lubricating oil composition for an automatic transmission of the present invention comprises
It has excellent low-speed sliding speed performance as well as low-speed sliding speed durability, and even when a low-speed range and a lock-up mechanism are adopted in an automatic transmission, stick-slip does not occur for that reason, and therefore, anti-shudder performance is improved. It has a high property that the prevention performance is long life, and an excellent property that the torque capacity is high.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C10M 129: 10 129: 54 159: 22 159: 24 137: 04) C10N 10:04 30:00 Z 30:06 40:04

Claims (1)

[Claims] 1. A base oil comprising a mineral oil and / or a synthetic oil, and at least one compound selected from the group consisting of (A) zinc dithiophosphate and basic zinc dithiophosphate on the basis of the total weight of the composition. 0.05 to 5% by weight, (B) an alkaline earth metal sulfonate, phenate, salicylate having at least one alkyl group having 8 or more carbon atoms,
And 0.05 to 5% by weight of at least one compound selected from the group consisting of these overbased salts, and (C) phosphoric acid ester, acidic phosphoric acid ester, phosphorous acid ester,
And a lubricating oil composition for an automatic transmission, which contains 0.01 to 5% by weight of at least one compound selected from the group consisting of acid phosphite.