JP2809448B2 - Fluid for traction drive - Google Patents

Description

The present invention relates to a traction drive fluid used for a traction drive device of an automobile or the like, and more particularly, to a fluid having a width from a low temperature (about -30 ° C) to a high temperature (about 140 ° C). The present invention relates to a traction drive fluid that can be used in a wide range.

[Problems to be solved by conventional technology and invention]

In recent years, reductions in the size and weight of traction drive devices have been studied mainly for automotive applications.

Generally, the size of a traction drive device is said to be inversely proportional to the traction coefficient of the traction oil used to the 0.45th power.The smaller the traction oil in the operating temperature range, the smaller the traction drive device. Can be planned.

For this reason, for example, JP-B-46-338 and JP-B-46-3
Various traction drive fluids have been studied and developed, including No. 39 publicity.

However, the pour point is generally good at low flowability-
A compound having a high temperature traction coefficient of 30 ° C. or lower has a low pour point of −30 ° C. or more, and a low temperature fluidity has a problem.

Therefore, from low temperature to high temperature (about -30 ℃ ~ 140 ℃
Wide range of excellent performance in the temperature range up to
High traction coefficient even at ℃, and -30
There has been a demand for a traction drive fluid having a pour point of less than or equal to ° C. and high thermal stability and oxidation stability.

[Means for solving the problem]

Therefore, the present inventors have intensively studied to solve such a problem. As a result, by including specific ultrafine particles in a specific base oil, it is possible to enhance the high-temperature traction coefficient by reinforcing the oil film shear strength and improving the high-temperature traction coefficient without impairing the low-temperature fluidity of low-viscosity compounds. They have found that a fluid can be obtained, and have completed the present invention based on this finding.

That is, the present invention relates to an alkylbenzene, a polybutene,
It is an object of the present invention to provide a traction drive fluid in which ultrafine particles having a particle diameter of 1500 ° or less are contained in a base oil selected from poly α-olefins, synthetic naphthenes, esters and ethers at a ratio of 3 to 40% by weight. .

In the present invention, ultrafine particles having a particle size (average particle size) of 1500 ° or less, preferably 1000 ° to 10 °, more preferably 500 ° to 10 ° are used. Here, when a material having a particle size of more than 1500 ° is used, there is no effect of improving the traction coefficient, and the rolling surface may be damaged.

As the ultrafine particles, those having various compositions can be used regardless of whether they are organic substances or inorganic substances. Specifically, for example, oxides such as zirconia, silica, titania, alumina, antimony oxide, iron oxide, and zinc oxide; nitrides such as boron nitride, silicon nitride, aluminum nitride, and titanium nitride; silicon carbide, titanium carbide; Tanks, carbides such as boron carbide, carbonates such as magnesium carbonate, barium carbonate and calcium carbonate, borides such as zirconium boride and tungsten boride, and inorganic substances such as sulfur and carbon black.
Further, organic materials that do not dissolve, such as polyimide, polyamide, polysulfone, epoxy resin, and phenol resin, can also be used. Of these, oxides are particularly stable and preferred.

These ultrafine particles may be dispersed as they are in an oil to be described later, or may be dispersed using a surfactant. Furthermore, the surface of the ultrafine particles is treated with a surfactant in advance to bind and adsorb. You may use it. Examples of the surfactant include anionic surfactants such as alkali salts of higher fatty acids, alkyl sulfates and alkyl sulfonates; cationic surfactants such as higher amine halides and quaternary ammonium salts; and polyethylene glycol alkyl ethers. And non-ionic activators such as polyethylene glycol fatty acid esters, sorbitan fatty acid esters and fatty acid monoglycerides.

In the present invention, the use of the ultrafine particles as described above has a feature that the shear strength of the oil film can be reinforced and the high-temperature traction coefficient can be improved without impairing the low-temperature fluidity of the low-viscosity compound.

In the present invention, as the traction oil (base oil) in which the ultrafine particles are to be dispersed, alkyl benzene, polybutene, poly α-olefin, synthetic naphthene,
Examples include those selected from esters and ethers.

In the present invention, among these, alkylbenzene, polybutene, and synthetic naphthene are particularly preferred.

Here, as the synthetic naphthene, an alkane derivative having two or more cyclohexane rings, an alkane derivative having one or more decalin rings and one or more cyclohexane rings, an alkane derivative having two or more decalin rings, a cyclohexane ring or a decalin ring is used. There are a compound having a structure in which two or more are directly bonded, a compound having a norbornane ring, and the like.

Specifically, such a synthetic naphthene is, for example, 1
-Cyclohexyl-1-decalylethane; 1,3-dicyclohexyl-3-methylbutane; 2,4-dicyclohexylpentane; 1,2-bis (methylcyclohexyl) -2-methylpropane; 1,1-bis (methylcyclohexyl) -2-methylpropane; 2,4-dicyclohexyl-2-methylpentane; limonene dimer hydrogenation; pinene dimer hydrogenation; camphene dimer hydrogenation; vinyl norbornene dimer hydrogenation, etc. Can be mentioned.

The fluid for traction drive of the present invention contains the ultrafine particles as an essential component in the base oil.

Here, the content of the ultrafine particles is 3 to 40% by weight of the whole. When the content of the ultrafine particles is less than 3% by weight, the effect is small. On the other hand, when the content of the ultrafine particles exceeds 40% by weight, the viscosity is undesirably increased too much.

The traction drive fluid of the present invention is basically composed of the above two components. If necessary, an antioxidant, a rust inhibitor, a cleaning dispersant, a pour point depressant, a viscosity index improver, Extreme pressure agent, anti-wear additive, anti-fatigue agent, defoamer,
Various additives such as an oiliness improver and a colorant may be added in appropriate amounts.

〔Example〕

 Next, the present invention will be described in detail with reference to examples.

Comparative Example 1 Ethylbenzene 2700 was placed in a glass flask having an internal volume of 5.
g, 58 g of metallic sodium and 18 g of potassium hydroxide,
While heating to 120 ° C and stirring, 1100 g of α-methylstyrene
A mixture of ethylbenzene and 300 g of ethylbenzene was gradually added dropwise over 5 hours, and then stirred for 1 hour to carry out a reaction.

After completion of the reaction, the reaction mixture was cooled to separate and collect an oil layer. To the oil layer was added 200 g of methyl alcohol, and the mixture was washed three times with 5N hydrochloric acid aqueous solution 2 and saturated saline 2 each. Next, after drying over anhydrous sodium sulfate, unreacted ethylbenzene was distilled off using a rotary evaporator, and a fraction having a boiling point range of 106 to 108 ° C at 0.06 mmHg was further distilled under reduced pressure by 1350.
g obtained.

Next, 500 ml of this fraction was put into an autoclave having an internal volume of 1, and a nickel catalyst for hydrogenation (manufactured by Nikki Chemical Co., Ltd .; N
-113) Add 20g, add reaction temperature 200 ℃, hydrogen pressure 50kg / cm
Hydrogenated at ² G. After the completion of the reaction, the catalyst was removed, and the light components were stripped and analyzed. As a result, the hydrogenation rate was 99.9% or more, and it was confirmed that the hydrogenated product was 2,4-dicyclohexylpentane. .

 Its properties were as follows.

・ Kinematic viscosity 12.5cSt (40 ℃) 2.750cSt (100 ℃) ・ Viscosity index 47 ・ Specific gravity 0.8913 ・ Refractive index (▲ n ²⁰ _D ▼) 1.4832 ・ Pour point -57.5 ℃ Furthermore, the traction coefficient of this product is 60 ℃. From14
It was measured in a temperature (oil temperature) range of 0 ° C. The result is shown in FIG.

In addition, the measurement of the traction coefficient was all performed with a two-cylindrical friction tester. That is, one of two cylinders of the same size in contact with each other (each having a diameter of 52 mm and a thickness of 6 mm, a driven type having a radius of curvature of 10 mm, a flat type without crowning) is driven at a constant speed (1500 rpm). Then, the other was continuously rotated from 1500 rpm to 1750 rpm, a 7 kg load was applied to the contact portion between the two cylinders by a spring, and a tangential force generated between the two cylinders, that is, a traction force was measured to obtain a traction coefficient. This cylinder is made of bearing steel SUJ
-2 Mirror finish with maximum contact pressure of 112k
gf / mm ² .

Example 1 Ultrafine iron oxide particles having a particle size of 100 mm (manufactured by Okamura Oil Co., Ltd.) were dispersed in the product obtained in Comparative Example 1 at a ratio of 25% by weight to obtain a fluid having the following properties.

・ Kinematic viscosity 12.30 cSt (40 ° C) 4.020 cSt (100 ° C) ・ Viscosity index 73 ・ Specific gravity 1.0741 ・ Refractive index (▲ n ²⁰ _D ▼) 1.515 ・ Pour point -55 ° C Further, the traction coefficient of this fluid is 60 ° C. From14
FIG. 1 shows the results measured in the temperature range of 0 ° C.

Example 2 A fluid having the following properties was prepared in the same manner as in Example 1 except that ultrafine iron oxide particles having a particle size of 100 mm (manufactured by Okamura Oil Co., Ltd.) were dispersed at a ratio of 5% by weight. I got

・ Kinematic viscosity 13.28 cSt (40 ° C) 2.995 cSt (100 ° C) ・ Viscosity index 65 ・ Specific gravity 0.9253 ・ Refractive index (▲ n ²⁰ _D ▼) 1.4900 ・ Pour point -57.5 ° C From14
FIG. 1 shows the results measured in the temperature range of 0 ° C.

Example 3 Ultrafine particles of titania having a particle diameter of 1000 mm (manufactured by Teica Corporation) were dispersed in the product obtained in Comparative Example 1 at a ratio of 10% by weight to obtain a fluid having the following properties.

・ Kinematic viscosity 34.87 cSt (40 ° C.) 4.602 cSt (100 ° C.) ・ Viscosity index −15 ・ Specific gravity 0.9296 ・ Refractive index (▲ n ²⁰ _D ▼) 1.4924 ・ Pour point −55 ° C. ℃ to 14
FIG. 2 shows the results measured in the temperature range of 0 ° C.

Comparative Example 2 Ultrafine titania particles having a particle size of 2000 mm (manufactured by Teica Corporation) were dispersed in the product obtained in Comparative Example 1 at a ratio of 6% by weight to obtain a fluid having the following properties.

・ Kinematic viscosity 31.37 cSt (40 ° C.) 4.145 cSt (100 ° C.) ・ Viscosity index −68 ・ Specific gravity 0.9188 ・ Refractive index (▲ n ²⁰ _D ▼) 1.4891 ・ Pour point −55 ° C. ℃ to 14
FIG. 2 shows the results measured in the temperature range of 0 ° C.

As is clear from the above results and the drawings (FIGS. 1 and 2), the traction drive fluid of the present invention has a low pour point and can maintain a high traction coefficient in a high temperature range, It turns out that it is suitable as a working fluid.

〔The invention's effect〕

The traction drive fluid of the present invention has a high traction coefficient in a high temperature range and is excellent in low-temperature fluidity. Therefore, particularly as a traction oil for automobiles, from a low temperature to a high temperature (for example, from about -30 ° C to 140 ° C). ) Can be used in a wide range.

That is, the traction drive fluid of the present invention is:
In particular, since the traction coefficient is high in a high temperature range, it is possible to reduce the size and weight of the traction drive device, extend the life, and increase the output.

Further, the traction drive fluid of the present invention has excellent low-temperature fluidity, so that it can be used outdoors in winter and can be obtained at a low cost, and is therefore suitable as a traction drive fluid.

[Brief description of the drawings]

FIG. 1 shows oil temperatures of 60 ° C. to 1 in Examples 1 and 2 and Comparative Example 1.
It is a graph which shows the measured value of the traction coefficient at 40 degreeC. FIG. 2 shows an oil temperature of 60 ° C. to 14 ° C. in Example 3 and Comparative Example 2.
It is a graph which shows the measured value of the traction coefficient at 0 degreeC.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C10M 107/08 C10M 107/08 125/10 125/10 // C10N 10:08 10:16 40:04 (58) Fields surveyed (Int.Cl. ⁶ , DB name) C10M 171/06 C10M 125/10 C10N 40:04

Claims (4)

(57) [Claims] 1. An alkyl benzene, polybutene, poly α-
In a base oil selected from olefins, synthetic naphthenes, esters, and ethers, 3 to 40
A traction drive fluid that is contained in a percentage by weight. 2. The traction drive fluid according to claim 1, wherein the base oil is alkylbenzene, polybutene or synthetic naphthene. 3. The method according to claim 1, wherein the ultrafine particles are oxides.
A traction drive fluid as described. 4. The traction drive fluid according to claim 3, wherein the oxide is iron oxide or titania.