JP2003342594A - Lubricating oil composition and lubricating oil additive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil composition for an infinitely variable speed transmission imparting a high coefficient of friction, and to provide a lubricating oil additive imparting a high coefficient of friction by adding to the composition for the infinitely variable speed transmission. <P>SOLUTION: The lubricating oil composition used in the infinitely variable speed transmission comprises a base oil and an additive comprising an antimony based compound added to the base oil. The lubricating oil additive comprises the antimony based compound contained in the lubricating oil composition for the infinitely variable speed transmission. The use of the antimony based compound as the additive agent increases the coefficient of friction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil composition containing an additive for increasing a friction coefficient. The present invention also relates to a lubricant additive which is added to a lubricant to increase the coefficient of friction of the lubricant.

[0002]

2. Description of the Related Art In a belt type continuously variable transmission, torque is transmitted by frictional force between a belt and a pulley. In this case, the frictional force is determined by the pressing force of the pulley pressed against the belt and the coefficient of friction between the belt and the pulley. Therefore, in order to efficiently transmit the torque, it is necessary to increase the pressing force of the pulley or increase the coefficient of friction between the belt and the pulley. The coefficient of friction between the belt and the pulley depends on the performance of the lubricating oil used in the belt type continuously variable transmission.

Therefore, a lubricating oil which can increase the coefficient of friction between the belt and the pulley has been developed. These lubricating oils contain an additive composed of a compound that increases the friction coefficient of the iron surface by adhering to the surface of iron that is usually used in belts of belt type continuously variable transmissions. Specific examples of such a compound include compounds using phosphorus, calcium, boron, sulfur and the like.

[0004]

However, lubricating oils containing additives of these compounds have not been sufficient. That is, in the case of a continuously variable transmission for a large displacement vehicle, it is necessary to transmit a large torque between a belt and a pulley used in the continuously variable transmission. For example, it is necessary to transmit 1.5 to 2 times as much engine power as in the case of the current 2L continuously variable transmission.

Therefore, assuming that the coefficient of friction between the belt and the pulley is the same, it is necessary to increase the pressing force of the pulley that sandwiches the belt. However, increasing the pressing force of the pulley becomes a factor that reduces the durability of the belt. Therefore, the present situation is that the pressing force of the pulley cannot be greatly increased. Therefore, as a method of increasing the capacity of torque that can be transmitted while maintaining the durability of the belt, it has been pursued to improve the performance of the lubricating oil and increase the friction coefficient between the belt and the pulley.

However, it has been difficult to further increase the friction coefficient between the belt and the pulley by the method of improving the lubricating oil containing the additive containing the compound which has been used conventionally. Therefore, as an additive to be added to a lubricant used in a continuously variable transmission in order to increase the coefficient of friction, it has been required to develop an additive using a compound that has not been conventionally used.

Therefore, an object of the present invention is to provide a new lubricating oil composition which can be applied to a continuously variable transmission and which can provide a high friction coefficient.

Another object of the present invention is to provide a new additive capable of imparting a high friction coefficient to a lubricating oil composition by being added to the lubricating oil composition used in a continuously variable transmission. Especially.

[0009]

Means for Solving the Problems (1) As a result of earnest research, the present inventor has found that by adding an antimony compound to a lubricating oil for continuously variable transmission, the lubricating oil for continuously variable transmission has high friction. We have come to recognize that the coefficient can be given.

(2) Therefore, a lubricating oil composition for solving the above problems is a lubricating oil composition used in a continuously variable transmission, wherein the lubricating oil composition is a base oil and antimony added to the base oil. A lubricating oil composition comprising an additive comprising a system compound.

In this case, the antimony compound is preferably an antimony compound represented by the following chemical formulas [I] and [II]. In the following description, the “antimony compound represented by the chemical formulas [I] and [II]” means the antimony compound represented by the chemical formulas [I] and [II] below.

[0012]

[Chemical 5]

(A ₁ , A ₂ , and A _{3 in the} chemical formula [I] are respectively the following chemical formula [II].)

[0014]

[Chemical 6]

(R ₁ , R ₂ and R _{3 in the} chemical formula [II] are each hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.) Further, the antimony compound is represented by the chemical formula [II]. R ₁ ,
It is preferable that R ₂ and R ₃ are each a hydrocarbon group having 1 to 20 carbon atoms. In this case, the antimony compound is preferably any one of antimony-dithioalkyl carbamate, antimony ethoxide and antimony butoxide.

The content of the antimony compound is 0.1 to 5% by mass based on 100% by mass of the entire lubricating oil composition.
Is preferred.

Further, the base oil is preferably mineral oil. Further, the lubricating oil composition preferably contains a viscosity index improver and an antioxidant added to the base oil. Further, the continuously variable transmission is preferably a metal belt type continuously variable transmission.

(3) The additive for lubricating oil which solves the above problems is contained in a lubricating oil composition used in a continuously variable transmission,
It is an additive for lubricating oils characterized by comprising an antimony compound.

In this case, the antimony-based compound is preferably composed of the antimony-based compound represented by the chemical formulas [I] and [II].

Further, the antimony compound is represented by the chemical formula [II]
It is preferred that R ₁ , R ₂ and R ₃ in each are hydrocarbon groups having 1 to 20 carbon atoms. In this case, the antimony compound is preferably any one of antimony-dithioalkyl carbamate, antimony ethoxide and antimony butoxide. Further, the continuously variable transmission is preferably a metal belt type continuously variable transmission.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the lubricating oil composition and the lubricating oil additive of the present invention will be described below. Since the additive for lubricating oil of the present invention is used by being added to the lubricating oil composition of the present invention as an additive, it will be described together with the description of the lubricating oil composition of the present invention.

(Structure of Lubricating Oil Composition of the Present Invention and Additive for Lubricating Oil) The lubricating oil composition of the present invention contains a base oil and an additive comprising an antimony compound added to the base oil. Can be composed of

The lubricating oil composition of the present invention may contain a viscosity index improver, an antiwear agent, etc., in addition to the additive comprising a base oil and an antimony compound.

The base oil can be used without particular limitation as long as it is generally used as a base oil for lubricating oil. That is, mineral oil, synthetic oil and mixed oil thereof can be used.

Examples of mineral oils include paraffinic oils and hydrocarbon oils. However, it is not limited to these.

As the synthetic oil, an olefin oligomer,
Examples thereof include dibasic acid ester, polyol ester, polyalkylene glycol, polyether, alkylbenzene, alkylnaphthalene, etc., but are not limited thereto.

As the mixed oil, two or more kinds of the above-mentioned mineral oil and synthetic oil can be combined and constituted.

As an additive to be added to the base oil, an additive containing an antimony compound is used. The friction coefficient can be increased by adding the antimony compound. By adding this antimony compound as an additive to the continuously variable transmission lubricating oil, antimony adheres to metal components such as iron contained in the continuously variable transmission belt, pulley, etc. to form a film, It is believed to improve the coefficient of friction between the belt and the pulley.

In this case, it is preferable to use an additive containing an antimony compound represented by the chemical formulas [I] and [II]. This is because these additives are soluble in oil.

Examples of the antimony compound include antimony-dithioalkyl carbamate, antimony ethoxide, antimony butoxide and the like. In this case, the chemical formula [II]
It is preferable that each of R ₁ , R ₂ and R ₃ is a hydrocarbon group having 1 to 20 carbon atoms, and further, antimony-dithioalkyl carbamate, antimony ethoxide and antimony butoxide are more preferable. Antimony methoxide, which has 1 carbon atom, is difficult to dissolve in oil. On the other hand, it is considered that when the number of carbon atoms increases, the friction reducing effect of the hydrocarbon group is likely to appear, and the friction increasing effect of the antimony compound itself decreases.

The content of the antimony compound is about 0.1 to 5 with the total weight of the lubricating oil composition being 100%.
It is preferably set to mass%. Even if it is smaller or larger than this, the effect of improving the friction coefficient cannot be effectively exhibited. That is, if the addition amount exceeds 5% by mass, it becomes difficult to dissolve in the base oil, and the effect of improving the μ characteristic decreases. Further, if the addition amount is less than 0.1% by mass, it is difficult to form a film on the surface and the effect cannot be obtained.

Further, the lubricating oil composition of the present invention may contain a suitable amount of a viscosity index improver and an antioxidant in the base oil, if necessary.

As the viscosity index improver, one or two or more suitable substances selected from polymethacrylate, olefin copolymer, styrene-diene copolymer hydride, polyisobutylene and the like can be used. However, it is not limited to these. By adding the viscosity index improver, good temperature-viscosity characteristics with little change in viscosity with temperature can be obtained. In this case, the content of the viscosity index improver is 100 mass% of the entire lubricating oil composition.
%, The content can be generally about 0.1 to 10% by mass. If the amount is less than 0.1%, the viscosity characteristics required for the continuously variable transmission cannot be obtained. On the other hand, if the amount exceeds 10%, the viscosity becomes too high. Alternatively, there arises a problem that the shear stability of viscosity cannot be ensured as the lubricating oil composition.

Examples of the antioxidant include phenolic antioxidants such as 4-methyl 2,6 ditertiary butylphenol and 4,4-methylenebis 2,6 ditertiary butylphenol, phenyl α-naphthylamine, alkylphenyl α-diphenylamine, diphenylamine, alkyldiphenylamine. Appropriate one of amine-based antioxidants, organic sulfur compounds, organometallic compounds, etc.
One kind or two or more kinds can be selected and used. However, it is not limited to these. The content of the antioxidant can be generally about 0.01 to 10% by mass, with the total mass of the lubricating oil composition being 100%. 0.01
If it is less than%, the required antioxidant properties cannot be obtained. Further, if it exceeds 10%, the antioxidant property of the fluid itself does not change even if it is added.

The lubricating oil composition of the present invention may also contain an antiwear agent. If necessary, an appropriate amount can be used within a range that does not significantly reduce the friction coefficient. As the antiwear agent, one or more suitable compounds can be selected and used from sulfur compounds, phosphorus compounds, organometallic compounds and the like. In this case, the content of the antiwear agent can be generally about 0.01 to 10% by mass, with the total mass of the lubricating oil composition being 100%. If the content is large, the effects of the present invention may be impaired.

Further, the lubricating oil composition of the present invention may contain a friction modifier. Appropriate ones among fatty acids, fatty amines, fatty acid esters and the like can be used alone or in combination of two or more within a range that does not significantly reduce the friction coefficient. However, it is not limited to these. When the total weight of the lubricating oil composition is 100%, the content thereof can be generally 0.1 to 10% by mass.

Others To the lubricating oil composition of the present invention, a metal deactivator, an ashless dispersant, a pour point depressant, a defoaming agent, a corrosion inhibitor, etc. are appropriately added in an appropriate amount, if necessary. can do.

(Form of Use of Lubricating Oil Composition of the Present Invention and Lubricating Oil Additive of the Present Invention) The lubricating oil composition of the present invention is suitable as a lubricating oil for a continuously variable transmission, particularly a belt type continuously variable transmission. Can be used. By using it as the lubricating oil of the belt type continuously variable transmission, the friction coefficient between the belt and the pulley can be improved.

In this case, the belt can be usually used as a metal belt, and particularly preferably as a steel belt. By depositing iron in the belt to form a film, the coefficient of friction between the belt and the pulley can be improved.

Although it is preferably used for a continuously variable transmission, it can also be used as a lubricating oil composition for a normal automatic transmission.

The lubricating oil composition of the present invention can be formed by adding the lubricating oil additive of the present invention to a base oil used in a continuously variable transmission.

[0042]

EXAMPLES The lubricating oil composition of the present invention and the lubricating oil additive of the present invention will be described below with reference to Examples and Comparative Examples.
The present invention is not limited to these examples.

(1) Outline of measurement test Using the lubricating oil composition of the example and the lubricating oil composition of the comparative example, a measurement test for measuring the friction coefficient of these lubricating oil compositions was conducted. The method of measuring the friction coefficient is ASTM D271.
According to the method specified in 4, the test was performed using a high-speed LFW tester (block-on-ring tester).

Here, the outline of the main measurement test is shown in FIG. As shown in FIG. 1, using a block on ring tester,
Friction between the sliding surface 21 of the block-shaped test piece 20 and the sliding surface 11 of the ring-shaped test piece 10 by pressing the sliding surface 21 of the block-shaped test piece 20 against the sliding surface 11 of the rotating ring-shaped test piece 10. The coefficient was measured under lubrication of the lubricating oil composition A of Examples and Comparative Examples. The oil temperatures of these lubricating oil compositions A were all 100 ° C.

As the ring-shaped test piece 10, a standard ring manufactured by Farex Co. was used. Sliding surface 11 of ring-shaped test piece 10
Is a side peripheral surface of the ring-shaped test piece 10. In addition, the block-shaped test piece 20 uses a standard block manufactured by Farex,
One surface of the block-shaped test piece 20 was used as a sliding surface 21.

The sliding speed was 50.0 cm / s. The load is 6.75 kg (15 LB), 13.5 kg (30 LB)
LB), 22.5 kg (50 LB), 33.75 kg
The coefficient of friction at (75 LB) was measured. As the friction coefficient, the value after 1 minute from the start of the test was adopted.

(2) Lubricating Oil Compositions of Examples 1 to 3 The above-mentioned measurement test was conducted on the lubricating oil compositions of Examples 1 to 3 and the lubricating oil composition of Comparative Example.

Examples 1 to 3 are lubricating oil compositions composed of mineral oil, a viscosity index improver, an antioxidant, and an additive containing an antimony compound represented by the chemical formulas [I] and [II]. .

Comparative Example 1 is a lubricating oil composition which is composed of a mineral oil, a viscosity index improver and an antioxidant without adding an additive comprising an antimony compound.

Table 1 shows the blending ratio of each component of the lubricating oil compositions of Examples 1 to 3 and Comparative Example 1 with the total mass of the lubricating oil composition being 100%.

All the base oils in Table 1 were paraffinic mineral oils, and the viscosity index improvers were all polymethacrylates.
All antioxidants were phenolic. Example 1
For the additives of 3 to 3, A ₁ , A ₂ in the chemical formula [I],
A ₃ That antimony consisting formula [II] is a chemical formula shown below [II-a] - Using dithioalkylamino carbamate.

[0052]

[Table 1]

[0053]

[Chemical 7]

Examples 1 to 3 obtained as a result of the measurement test
FIG. 2 shows the relationship between the friction coefficient and the load of the lubricating oil composition of Comparative Example 1 and the lubricating oil composition of Comparative Example 1.

Comparing the lubricating oil compositions of Examples 1 to 3 with the lubricating oil composition of Comparative Example 1, the lubricating oil compositions of Examples 1 to 3 have improved friction coefficient. In particular, the lubricating oil compositions of Examples 2 and 3 have higher friction coefficients than the lubricating oil composition of Comparative Example 1. From this point, it is understood that the friction coefficient can be increased by adding an appropriate amount of antimony compound in consideration of the load.

(3) Lubricating oil compositions of Examples 4 to 7 Similarly, the above-described measurement test was performed on the lubricating oil compositions of Examples 4 to 7 and the lubricating oil composition of Comparative Example 2.

Examples 4 to 7 are lubricating oil compositions composed of mineral oil, a viscosity index improver, an antioxidant and an additive containing an antimony compound represented by the chemical formulas [I] and [II]. .

Comparative Example 2 is a lubricating oil composition which is composed of a mineral oil, a viscosity index improver and an antioxidant without the addition of an antimony compound additive.

Table 2 shows the blending ratio of each component of the lubricating oil compositions of Examples 4 to 7 and Comparative Example 2 with the total weight of the lubricating oil composition being 100%.

All base oils shown in Table 2 were paraffinic mineral oils, all viscosity index improvers were polymethacrylates, and all antioxidants were phenols.

Regarding the additives of the lubricating oil compositions of Examples 4 to 5, A ₁ , A ₂ , A _{3 in} the chemical formula [I], that is, the chemical formula [I
I] was an antimony ethoxide in which ethoxide (n-C ₂ H ₅ O) was used. In addition, regarding the additives of the lubricating oil compositions of Examples 6 to 7, antimonybu, in which A ₁ , A ₂ , A _{3 in the} chemical formula [I], that is, the chemical formula [II] is butoxide (n-C ₄ H ₉ O). Toxide was used.

[0062]

[Table 2]

Examples 4 to 7 obtained as a result of the measurement test
FIG. 3 shows the relationship between the friction coefficient and the load of the lubricating oil composition of Comparative Example 2 and the lubricating oil composition of Comparative Example 2.

When the lubricating oil compositions of Examples 4 to 7 and the lubricating oil composition of Comparative Example 2 are compared, the lubricating oil compositions of Examples 4 to 7 have higher friction coefficients. From this point, it is understood that the friction coefficient can be increased by adding an appropriate amount of antimony compound in consideration of the load.

[0065]

The lubricating oil composition of the present invention can give a high friction coefficient when used as a lubricating oil for a continuously variable transmission.

The lubricating oil additive of the present invention is added to a lubricating oil composition used in a continuously variable transmission, thereby providing the lubricating oil composition with a high friction coefficient. can do.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a friction coefficient measurement test.

FIG. 2 is a diagram showing a relationship between a load and a friction coefficient obtained by a measurement test for Examples 1 to 3 and Comparative Example.

FIG. 3 is a diagram showing a relationship between a load and a friction coefficient obtained by a measurement test for Examples 4 to 7 and Comparative Example.

[Explanation of symbols]

10: Ring-shaped test piece 11: Sliding surface of ring-shaped test piece 20: Block-shaped test piece 21: Sliding surface of block-shaped test piece A: Lubricating oil composition

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10N 30:06 C10N 30:06 40:04 40:04 (72) Inventor Toshihide Omori Nagakute-cho, Aichi-gun, Aichi 1 in Toyota Central Research Institute, Ltd. at 41 Chuo Yokoido (72) Inventor Mamoru Toyama 1 in 41 Toyota Central Research Institute, Nagakute Town, Aichi-gun, Aichi Prefecture F-Term (Reference) 4H104 BB02C BG10C DA02A EB02 FA05 LA03 PA03

Claims (13)

[Claims] 1. A lubricating oil composition used in a continuously variable transmission, wherein the lubricating oil composition contains a base oil and an additive made of an antimony compound added to the base oil. A characteristic lubricating oil composition. 2. The lubricating oil composition according to claim 1, wherein the antimony compound is represented by the following chemical formulas [I] and [II]. [Chemical 1] (A ₁ , A ₂ , and A _{3 in the} chemical formula [I] are respectively the following chemical formula [II].) (R ₁ , R ₂ , and R _{3 in the} chemical formula [II] are each hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.) 3. The antimony compound has the chemical formula [I
The lubricating oil composition according to claim ₂ , wherein R ₁ , R ₂ and R _{3 in [} I] are each a hydrocarbon group having 1 to 20 carbon atoms. 4. The lubricating oil composition according to claim 3, wherein the antimony compound is any one of antimony-dithioalkyl carbamate, antimony ethoxide and antimony butoxide. 5. The lubricating oil composition according to claim 1, 2, 3 or 4, wherein the content of the antimony compound is 0.1 to 5 mass% based on the total mass of 100%. 6. The base oil is mineral oil as claimed in claim 1,
The lubricating oil composition according to 3, 4, or 5. 7. The lubricating oil composition according to claim 1, wherein the lubricating oil composition contains a viscosity index improver and an antioxidant added to the base oil. . 8. The lubricating oil composition according to claim 1, wherein the continuously variable transmission is a metal belt type continuously variable transmission. 9. An additive for lubricating oil, which is contained in a lubricating oil composition used in a continuously variable transmission and is composed of an antimony compound. 10. The additive for lubricating oil according to claim 9, wherein the antimony compound is represented by the following chemical formulas [I] and [II]. [Chemical 3] (A ₁ , A ₂ , and A _{3 in the} chemical formula [I] are respectively the following chemical formula [II].) (R ₁ , R ₂ , and R _{3 in the} chemical formula [II] are each hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.) 11. The antimony-based compound has a chemical formula
R in [II]₁, R₂, R ₃Each has 1 to 20 carbons
The lubricating oil additive according to claim 10, which is a hydrocarbon group. 12. The lubricating oil additive according to claim 11, wherein the antimony compound is any one of antimony-dithioalkyl carbamate, antimony ethoxide and antimony butoxide. 13. The additive for lubricating oil according to claim 9, 10, 11 or 12, wherein the continuously variable transmission is a metal belt type continuously variable transmission.