JPH0252958B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traction drive fluid with low viscosity, excellent traction coefficient, and low temperature dependence of viscosity, which is suitable for continuously variable transmissions of automobiles or industrial machines.

The fluid for traction drive is traction drive (friction drive device using rolling contact),
For example, continuously variable transmissions for automobiles, continuously variable transmissions for industrial use,
It is a fluid used in hydraulic equipment, etc., and is required to have a high traction coefficient, stability against heat and oxidation, and economic efficiency.

In recent years, traction drive devices that use such fluid for traction drive have become increasingly compact and used under high load conditions. When using a traction drive device under such severe conditions, it is necessary to use a traction drive fluid that exhibits sufficient performance even under various temperature conditions. Various traction drive fluids have been proposed so far. For example,
−338 Publication, Special Publication No. 1973-339, Special Publication No. 1977-
Publication No. 35763, Special Publication No. 48-42067, Special Publication No. 1973
-42068 Publication, Japanese Patent Publication No. 53-36105, Japanese Patent Publication No. Sho
Examples include those described in Publication No. 55-43108 and Japanese Patent Application Laid-Open No. 55-40726. However, these have problems in that their viscosity is relatively large, reducing power transmission efficiency due to stirring loss, and the viscosity is highly temperature dependent.

Therefore, the inventors of the present invention conducted intensive research to develop a traction drive fluid that has an excellent traction coefficient, low viscosity, and low temperature dependence of viscosity. The present invention was completed based on the discovery that the contained traction drive fluid has the desired characteristics.

That is, the present invention is based on the general formula (In the formula, R ¹ and R ² each represent a methyl group or an ethyl group.) This is a traction drive fluid containing a compound represented by the following as a base stock.

As a compound represented by the above general formula (),
Specifically, the following can be mentioned.

formula 2,4-dicyclohexylpentane, represented by the formula 2,4-dicyclohexylhexane, represented by the formula 3,5-dicyclohexylheptane represented by:

In the present invention, these compounds may be used alone or in combination as the base stock of the traction drive fluid.

The compound represented by the general formula () can be produced by various methods, and the present invention is not particularly limited and can be produced by various methods. Generally, alkylbenzenes such as ethylbenzene or propylbenzene and α
- It can be obtained by reacting an α-alkylstyrene such as methylstyrene or α-ethylstyrene in the presence of metallic sodium or the like, and then hydrogenating the resulting product in the presence of a hydrogenation catalyst. Here, the conditions for the reaction between alkylbenzene and α-alkylstyrene may be determined as appropriate depending on various situations, but usually the reaction between alkylbenzene and α-alkylstyrene is carried out at 50 to 150°C in the presence of a basic reaction catalyst such as sodium. All you have to do is react.
Additionally, the conditions for hydrogenation treatment cannot be unambiguously determined depending on the raw materials, type of catalyst, etc.
The reaction may be carried out at room temperature to 300° C. and hydrogen pressure of normal pressure to 200 Kg/cm ² G using various commonly known catalysts containing metals such as nickel, molybdenum, platinum, palladium, ruthenium, and rhodium.

The compound represented by the general formula () obtained in this way can be used alone or in a mixture of two or more as a base stock for a traction drive fluid, and has an excellent traction coefficient. In addition to this, it also has good thermal stability. Furthermore, the compound of general formula () can be produced relatively inexpensively by the above-mentioned method, and therefore the traction drive fluid of the present invention is inexpensive. Furthermore, since it has a low viscosity, there is no reduction in power transmission efficiency due to stirring loss, and it can also be used as a diluent for other high-viscosity traction drive fluids.

As described above, the traction drive fluid of the present invention has a high traction coefficient and low viscosity, so it has high power transmission efficiency. Moreover, it has a large viscosity index, that is, the temperature dependence of viscosity is small, and furthermore, it has good thermal stability.

Therefore, the traction drive fluid of the present invention is widely used in various mechanical products such as continuously variable transmissions of automobiles and hydraulic equipment.

Next, examples of the present invention will be shown.

Example 1 Ethylbenzene in a glass flask with an internal volume of 5
2700 g of sodium metal, 58 g of metallic sodium, and 17 g of isopropyl alcohol were heated to 120°C, and while stirring, a mixture of 1100 g of α-methylstyrene and 300 g of ethylbenzene was gradually added dropwise over 5 hours, and then stirred for 1 hour to react. I did this.

After the reaction was completed, the oil layer was separated and collected by cooling, and 200 g of methyl alcohol was added thereto, followed by washing three times each with two parts of a 5N hydrochloric acid solution and two parts of a saturated saline solution. Next, after drying with anhydrous sodium sulfate, unreacted ethylbenzene was distilled off using a rotary evaporator, and then 0.06mm
1500g of distillate with a boiling point range of 104-110℃ in Hg
Obtained. As a result of analysis, this fraction was confirmed to be 2,4-diphenylpentane.

Next, 500 ml of this fraction was placed in an autoclave with an internal volume of 1, and 20 g of a nickel catalyst for hydrogenation (manufactured by JGC Chemical Co., Ltd., N-113 catalyst) was added to react at a reaction temperature of 200°C and a hydrogen pressure of 50 kg/cm ^{2 .} Hydrotreated in G. After the reaction was completed, the catalyst was removed, the light components were stripped, and the hydrogenation rate was 99.9.
% or more, and this hydrogenation product was confirmed to be 2,4-dicyclohexylpentane.
The specific gravity of this product was 0.89 (15/4°C), the kinematic viscosity was 11.5 cSt (40°C), 2.69 cSt (100°C), the viscosity index was 52, and the traction coefficient was 0.086.

The traction coefficient was measured using a two-cylinder friction tester. In other words, one cylinder of the same size (diameter 60 mm, thickness 6 mm) that is in contact with a line is rotated at a constant speed (2000 r.pm), and the other cylinder is rotated at a slower constant speed (1700 r. pm).
A load of 140 kg was applied by a spring to the contact area between both cylinders, and the torque was measured using a strain gauge and a torque meter to determine the traction coefficient. This cylinder is made of carbon steel SCM-3, the surface is buffed with alumina (0.03μ), the surface roughness is R _nax = 0.2μ, and the Hertzian contact pressure is 75
It was Kg/ ^mm2 . The temperature of the oil used in the test was adjusted to 20 cSt.

Furthermore, as a result of conducting a thermal stability test on this 2,4-dicyclohexylpentane at 170°C for 24 hours in accordance with JIS-K-2540, no sludge formation was observed, and no color change was observed. Nakatsuta.

Comparative Example 1 1200 ml of p-methylstyrene and 300 ml of 55% sulfuric acid were placed in a glass flask with an internal volume of 3, and the mixture was reacted at 110° C. for 2 hours with stirring. After stirring,
The mixture was allowed to stand still and separated into an aqueous layer and an oil layer, and the oil layer was washed three times each with 1 part of a 3% aqueous sodium hydroxide solution and 1 part of a saturated saline solution, and then dried over anhydrous sodium sulfate. After distilling off unreacted p-methylstyrene, 600 g of a fraction with a boiling point of 144-153°C/0.2 mmHg was obtained.
Analysis of this fraction confirmed that it was a mixture of 98% linear dimer and 2% cyclic dimer of p-methylstyrene.

This fraction was hydrogenated and post-treated in the same manner as in Example 1 to obtain a traction drive fluid containing a hydrogenated linear dimer of p-methylstyrene as a main component.

The properties of the compound obtained by hydrogenation are: specific gravity (15/4℃) 0.88, kinematic viscosity 11.4cSt (40℃), 2.6cSt
(100°C), viscosity index 26, and viscosity 20 cSt, the traction coefficient was 0.077. Although this compound is similar in chemical structure to the compound of the present invention, it was found that both the viscosity index and the traction coefficient were lower.

Comparative Example 2 800 g of phenylcyclohexane, 200 g of n-hexane, and 300 g of concentrated sulfuric acid were placed in the glass flask of 3.
g and cooled to 0°C. While stirring the reaction temperature at 0° C., 260 g of styrene was added dropwise over 3 hours, and the reaction was further stirred for 1 hour. After the stirring was stopped, the mixture was allowed to stand, the sulfuric acid layer and the oil layer were separated, and the oil layer was washed three times each with 1 part of a 3% aqueous sodium hydroxide solution and 1 part of saturated brine, and then dried over anhydrous sodium sulfate. After distilling off the solvent n-hexane and unreacted phenylcyclohexane, the boiling point
520g of a 130-143°C/0.15mmHg fraction was obtained.

As a result of analysis, this fraction was found to be 1-phenyl-1-
It was confirmed to be (cyclohexyl phenyl) ethane.

This fraction was hydrogenated and post-treated in the same manner as in Example 1 to obtain 1-cyclohexyl-1-(dicyclohexyl)ethane.

The properties of this compound are specific gravity (15/4℃) 0.93, kinematic viscosity 68.0cSt (40℃), 6.57cSt (100℃), viscosity index -6, and traction coefficient at viscosity 20cSt.
It was 0.084.

Although this compound exhibited a traction coefficient equivalent to that of the compound of the present invention, it was found to have a high viscosity and a low viscosity index.

Claims (1)

[Claims] 1. General formula (In the formula, R ¹ and R ² each represent a methyl group or an ethyl group.) A traction drive fluid containing a compound represented by the following as a base stock.