JP2001288488A - Labricating oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lubricating oil having a high friction factor between metals on a metallic belt and also a long life for shudder prevention. SOLUTION: A lubricating oil composition contains (a) an alkaline earth metal sulfonate or phenate, (b) an imide compound and (c) a phosphorus compound in a base oil of the lubricating oil, in which a high friction factor between metals by a block-on-disk test is 0.13 or more, and a life for shudder prevention by low speed sliding prescribed in JASO M349-95 is 150 hours or more.

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 and, more particularly, to a metal belt type continuously variable transmission having a high coefficient of friction between metals and a long service life of preventing shudder in a wet clutch of a lock-up clutch or a starting clutch. A lubricating oil composition.

[0002]

2. Description of the Related Art In recent years, improvement of fuel efficiency has become an important issue for automobiles due to global environmental problems. The mounting ratio of a metal belt type continuously variable transmission (hereinafter, sometimes abbreviated as a belt CVT), which has higher efficiency than a conventional multi-stage automatic transmission (AT), is increasing. The mounted vehicle has a wide range of displacement from 0.66 L to 2 L, and the larger the capacity, the higher the torque transmission capacity of the metal belt, that is, the higher the coefficient of friction between metals. In addition, a torque converter with a lock-up clutch or a wet start clutch is used as a start element for the purpose of improving fuel efficiency, and if a shudder (self-excited vibration) occurs in this part at the time of engagement, ride comfort is extremely deteriorated. . Therefore, a long anti-shudder life is desired. However, with respect to conventional lubricating oils for belt CVTs, research on improving the metal friction coefficient has been mainly conducted (JP-A-11-92779, JP-A-11-92779).
No. 293272), and there is no research and development on a lubricating oil that pursues both the performance of preventing the shudder of a wet clutch and extending the life. Also, as a result of the experiment, a commercially available belt CVT
It was found that lubricating oils having a high intermetal friction coefficient had a short anti-shudder life, and those having a long anti-shudder life had a low metal friction coefficient.

[0003]

SUMMARY OF THE INVENTION The present invention provides a lubricating oil having a high coefficient of friction between metals in a metal belt and a long anti-shudder life.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies to solve the above-mentioned problems, lubricating oils for conventional continuously variable transmissions having a high metal friction coefficient contain zinc dithiophosphate for the purpose of improving the metal friction coefficient. It has been found that this causes clogging of a wet clutch such as a lock-up clutch or a starting clutch and causes a shudder at the time of engagement. Therefore, in order to solve the above-mentioned problems, it has been found that it is important to add an additive which does not cause clogging of the clutch and improves the friction coefficient between metals. The present invention has been completed based on such findings. That is, in the present invention, the lubricating base oil contains (a) an alkaline earth metal sulfonate or finate, (b) an imide compound and (c) a phosphorus-based compound, and has a coefficient of friction between metals of 0. 13 or more and JAS
It is intended to provide a lubricating oil composition characterized by having a life of preventing shudder due to low-speed slip specified in OM349-1998 of 150 hours or more.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The base oil in the lubricating oil composition of the present invention is not particularly limited, and may be ATF or continuously variable transmission oil (CVT).
Any mineral oil or synthetic oil can be used as long as it can be used as F). Examples of the mineral oil include a paraffin-based mineral oil, an intermediate-based mineral oil, and a naphthenic-based mineral oil, and specific examples thereof include light neutral oil, medium neutral oil, heavy neutral oil, and bright stock. . Examples of the synthetic oil include polybutene, polyolefin [α-olefin homopolymer and copolymer (eg, ethylene-α-olefin copolymer), etc.], various esters (eg, polyol ester, dibasic acid ester) , Phosphate esters),
Examples include various ethers (for example, polyphenyl ether), polyglycol, alkylbenzene, alkylnaphthalene, and the like. Of these, polyolefins and polyol esters are particularly preferred. In the present invention, as the base oil, one kind of the above mineral oils may be used, or two or more kinds may be used in combination. Further, one kind of the above synthetic oils may be used, or two or more kinds may be used in combination. Further, one or more mineral oils and one or more synthetic oils may be used in combination.

The lubricating oil composition of the present invention comprises the above lubricating base oil containing (a) an alkaline earth metal sulfonate or finate, (b) an imide compound and (c) a phosphorus compound. is there. The alkaline earth metal sulfonate or finate of the component (a) functions as a metal-based detergent, and specific examples thereof include calcium sulfonate, calcium finate, magnesium sulfonate, and barium sulfonate. They can be used alone or in combination.
These alkaline earth metal sulfonates or finates may be overbased with hydroxides or carbonates of alkaline earth metals, and have a base number as low as 10 to 100 mgKOH / g by the perchloric acid method. One or both of a base number alkaline earth metal salt and a high base number alkaline earth metal salt having a base number of 100 to 500 mgKOH / g can be used in combination. The metal content is important for increasing the intermetallic friction coefficient, but an inadequate composition has a low intermetallic friction coefficient, and an excessive composition adversely affects the anti-shudder life. Also, to extend the anti-shudder life,
The effect of the amount of soap is strong. Therefore, the component (a) has a metal content in the range of 300 to 2500 ppm and a soap amount of 0.3% by weight or more, preferably 0.3 to 2.5% by weight.
Is important.

The imide compound of the component (b) includes a succinimide compound and / or a boron-based imide compound, and one or more of these compounds can be used. Examples of the succinimide compounds include alkyl succinimides or alkenyl succinimides. Among them, the molecular weight of the alkyl or alkenyl is preferably in the range of 400 to 2500, and the alkyl or alkenyl succinimide is preferably 1 mole per mole of the amine. A compound obtained by reacting 1 to 3 moles of an acid anhydride. The boron imide compound is obtained by treating the above succinimide compounds with boric acid or a boric acid derivative. The imide compound as described above functions as a dispersant (ashless dispersant), and its blending amount is preferably 1.5% by weight or more, and is preferably in the range of 1.5 to 10% by weight. More preferably, If the amount is too small, the coefficient of friction between metals is low, so that the object of the present invention cannot be achieved. If the amount is too large, the shudder prevention life is short, and the object of the present invention cannot be achieved. Further, besides the above-mentioned succinimide compounds, benzylamine compounds can be used as the ashless dispersant. Examples of the benzylamine compounds generally include alkyl-substituted or alkenyl-substituted benzylamines, and are compounds obtained by subjecting 1 mol of an amine to 1 to 3 mol of an alkyl or alkenyl phenol by a Mannich reaction. The benzylamine compounds include those treated with boric acid or a boric acid derivative with an acid.

[0008] The lubricating oil composition of the present invention further contains a phosphorus compound as the component (c). Here, examples of the phosphorus-based compound include a phosphate ester compound and / or a phosphite ester compound, and improve the friction coefficient between metals in combination with the above-mentioned components (a) and (b). If the amount is too small, the metal friction coefficient is low,
Since the object of the present invention cannot be achieved, the content is preferably 0.1% by weight or more, and more preferably 0.1 to 2.0% by weight. As the phosphate ester compound and / or the phosphite ester compound, various compounds can be used, and specific examples thereof include aliphatic phosphate esters such as tributyl phosphate, tri-2-ethylhexyl phosphate, and tributoxy phosphate. , Tricresyl phosphate, Triphenyl phosphate, Trixylenyl phosphate, Cresyl diphenyl phosphate, 2
Aromatic phosphates such as -ethylhexyl diphenyl phosphate, mono- or di-butyl acid phosphate, mono- or di-2-ethylhexyl acid phosphate, mono- or di-isodecyl acid phosphate, mono- or di-lauryl acid phosphate Acid phosphates such as mono- or di-oleyl acid phosphates and amine salt compounds thereof, and aliphatics such as tributyl phosphite, trioctyl phosphite, trisdecyl phosphite, tristridecyl phosphite and trioleyl phosphite Phosphite, triphenyl phosphite, tricresyl phosphite, trisnonyl phenyl phosphite, diphenyl mono-2-ethylhexyl phosphite, diphenyl mono tridecyl phosphite Aromatic phosphites, such as, dibutyl hydrogen phosphite, di -2
-Aliphatic hydrogen phosphites such as ethylhexyl hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, aromatic hydrogen phosphites such as diphenyl hydrogen phosphite, dicresyl hydrogen phosphite, Sulfur-containing phosphorus compounds such as triphenyl phosphorothionate, trisnonylphenyl phosphorothionate, trilauryl thiophosphite, S-octylthioethyl hydrogen phosphite, S-dodecyl thioethyl hydrogen phosphite and the like. Can be. These may be used alone or in appropriate combinations of two or more.

The lubricating oil composition of the present invention may further contain other additives such as an antioxidant, an extreme pressure agent, a copper deactivator, and a friction modifier as long as the object of the present invention is not impaired. Agents, defoamers, viscosity index improvers and the like can be added. In addition, various polymers, for example, polymethacrylate (PMA) or nitrogen-containing dispersed PMA can be blended. Examples of the antioxidant include amines (diphenylamines, naphthylamines),
Examples include phenol-based and sulfur-based antioxidants.
Examples of the friction modifier include carboxylic acids, carboxylic esters, oils and fats, carboxylic amides (reacted products of amines such as polyalkylene polyamines, alkanolamines and alkylamines with carboxylic acids), alkylamines,
Examples thereof include N-alkylalkanolamines and partial esters of carboxylic acids and polyhydric alcohols.

[0010] The lubricating oil composition of the present invention has a coefficient of friction between metals of 0.13 or more and an anti-shudder life of 150 hours or more by containing the above components in combination. Thus, the anti-shudder life can be significantly extended while maintaining a high intermetallic friction coefficient.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Examples 1 to 14 and Comparative Examples 1 to 9 For the lubricating oil compositions having the component compositions shown in Table 1, the coefficient of friction between metals and the anti-shudder life were measured by the following test methods and conditions, and the results were shown in Table 1. Shown in The substances used in Examples and Comparative Examples are as follows. Base oil: High base number Ca sulfonate: Base number 300 mg KOH /
g of Ca sulfonate Low base number Ca sulfonate: base number 40 mg KOH / g
Ca sulfonate of high base number Ca finate: base number 250 mgKOH /
g Ca finate High base number Mg sulfonate: base number 300 mg KOH /
g of Mg sulfonate High base number Ba sulfonate: base number 200 mg KOH /
g of Ba sulfonate Other additives: Other additives are the same compound and the same addition amount of antioxidant, copper deactivator, pour point depressant, friction modifier and defoamer in each case.

Evaluation of friction coefficient between metals Evaluation was made using a block-on-disk test apparatus shown in FIG. The test oil 1 is put into the block-on-disk test apparatus, a load is applied between the three blocks 2 and the disk 3, which are the test pieces, and the load cell 4 detects the rotational torque due to the friction when the upper part is rotated. I do. The measurement conditions are as follows. ・ Conditioning pressure: 100MPa Oil temperature: 100 ° C Sliding speed: 0.1m / sec Time: 30 minutes ・ Performance measuring surface pressure: 200MPa Oil temperature: 100 ° C Sliding speed: 0.1m / sec

[0013] Anti-shudder life According to JASO M349-1998, evaluation was made under the following conditions using a low-speed sliding tester. ・ Conditioning pressure: 1 MPa Oil temperature: 80 ° C. Sliding speed: 0.6 m / sec Time: 30 minutes ・ Durability test conditions Friction material: Cellulose disc / steel plate Oil volume: 150 ml Surface pressure: 1 MPa Oil temperature: 120 C. Slip speed: 0.9 m / s Slip time: 30 minutes Pause time: 1 minute Performance measurement: Measure μ-V characteristics every 24 hours after 0 hours Evaluation of shudder prevention life is dμ / dV at 50 rpm.
It is evaluated by the time until <0.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

[0017]

[Table 4]

[0018]

The lubricating oil composition of the present invention comprises a metal belt C
The coefficient of friction between metals related to the torque transmission capacity of the VT can be kept high, and the life of preventing the shudder in the lock-up clutch or the starting clutch can be greatly extended. This is effective for maintaining the riding comfort and improving fuel efficiency in an automobile equipped with a torque converter with a lock-up clutch or a belt CVT having a starting clutch, and is highly useful as a lubricant for the belt CVT.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a block-on-disk tester used for measuring a friction coefficient between metals in Examples and Comparative Examples.

[Explanation of symbols]

 1 Test oil 2 Block 3 Disk 4 Load cell

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Claims (5)

[Claims] 1. A lubricating base oil containing (a) an alkaline earth metal sulfonate or finate, (b) an imide compound and (c) a phosphorus compound, and having a friction coefficient between metals of 0.13 according to a block-on-disk test. Above, and JAS
A lubricating oil composition having a shudder prevention life of at least 150 hours due to low-speed sliding specified in OM349-1998. 2. The alkaline earth metal sulfonate or finate of component (a) is at least one selected from the group consisting of calcium salts, magnesium salts and barium salts, the metal content is 300 to 2500 ppm, and the soap amount is 0. .
The lubricating oil composition according to claim 1, which is contained in an amount of 3% by weight or more. 3. The imide compound of component (b) is at least one member selected from the group consisting of succinimides and boron-based imides, and the compounding amount is 1.5% by weight or more. Lubricating oil composition. 4. The phosphoric compound as the component (c) is at least one selected from the group consisting of phosphate ester compounds and phosphite ester compounds, and the compounding amount thereof is 0.2% by weight or more. A lubricating oil composition according to claim 1. 5. The lubricating oil composition according to claim 1, which is used for a continuously variable transmission having a torque converter with a lock-up clutch or a starting clutch.