Mineral oils: processes and products – Products and compositions – Lubricating oils
Reexamination Certificate
2000-12-15
2003-10-28
Griffin, Walter D. (Department: 1764)
Mineral oils: processes and products
Products and compositions
Lubricating oils
C208S018000, C585S002000, C585S003000, C508S462000, C508S484000, C508S486000, C508S499000
Reexamination Certificate
active
06638417
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to traction drive fluids. The invention relates particularly to traction drive fluids which can be used not only in driving force transmitting mechanisms but also in hydraulic pressure controlling mechanisms and friction characteristics controlling mechanism using a wet-type clutch, and more particularly to traction drive fluids which are suitably used in continuously variable transmissions of traction drive type of automobiles.
2. Background Art
In the field of machinery for industrial use, traction drive fluids have been used in force transmitting device of traction drive type which form the thin film of the traction drive fluid and transmit power via the film. Such traction drive fluids have been demanded to be high in traction drive coefficient which indicates the capability of transmitting driving force.
Recently, the research and development of traction drive fluids have been progressed to utilize them in the continuously variable transmissions of an automobile. When used for an automobile, a traction drive fluid is used not only in the driving force transmission mechanism but also in the hydraulic pressure controlling mechanism and the friction characteristic controlling mechanism of the wet-type clutch.
A lubricant known as automatic transmission fluid (ATF) has been used for the hydraulic controlling mechanism of the transmission and the friction characteristics controlling mechanism of the wet-type clutch of an automobile. It is a well-known fact that such ATF is required to be higher in a kinematic viscosity at elevated temperatures than a certain level and superior in flowability at low temperatures so as to perform the role of the hydraulic controlling mechanism. It is also well known that an ATF needs to be blended with additives having excellent friction characteristics, particularly anti-shudder characteristics for fulfilling the requirements in performing the role of the friction characteristics controlling mechanism, particularly the controlling mechanism having in addition slip controlling capability.
Therefore, when used in the continuous variable transmission of traction drive type of an automobile, a traction drive fluid is required to have its peculiar driving force transmitting capability but also capabilities as a fluid for the hydraulic controlling and friction characteristics controlling of a wet-type clutch, both of which are required for ATF.
SANTOTRAC is a commercially available traction drive fluid manufacture by Nippon Mitsubishi Oil Corporation and widely known to have an excellent power transmitting capability. However, traction drive fluids to be used in automobile continuously variable transmissions are required to have flowability at low temperatures and other performances, but such traction drive fluids have not been placed on the market yet.
In view of the current situations, the object of the present invention is to provide a traction drive fluid which is superior not only in power transmitting capability but also capabilities required as a fluid for a hydraulic controlling mechanism, i.e. flowability at low temperatures and capabilities required as a fluid for a wet type friction controlling mechanism.
SUMMARY OF THE INVENTION
Intensive research and efforts made to solve the foregoing problems resulted in the development of a traction drive fluid particularly suitable for use in continuous variable transmission of traction drive type of automobiles, more specifically a traction drive fluid which can be used not only in hydraulic controlling mechanism and friction characteristic controlling mechanism of wet clutches.
According to a first aspect of the present invention, there is provided a traction drive fluid comprising a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
4
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, and A is a naphthenic hydrocarbon group, a saturated polycyclic hydrocarbon group, a naphthenic ester group, and a naphthenic carbonate group.
According to a second aspect of the present invention, there is provided a traction drive fluid comprising a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
8
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, and B is an alkylene group or indicates the form of bond between the two naphthenic rings selected from the group consisting of a direct bond, an ester bond, and a carbonate bond.
According to a third aspect of the present invention, there is provided a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
8
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms.
According to a forth aspect of the present invention, there is provided a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
8
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, and at least one of R
2
, R
3
, R
6
and R
7
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms.
According to a fifth aspect of the present invention, there is provided a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
8
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, and at least one of R
2
, R
3
, R
6
and R
7
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms.
According to a sixth aspect of the present invention, there is provided a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
8
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms.
According to a seventh aspect of the present invention, there is provided a naphthenic compound represented by the formula
wherein R
1
is an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms, R
2
through R
8
are each independently hydrogen or an alkyl group, which may have a naphthene ring, having 1 to 8 carbon atoms.
Furthermore, a traction drive fluid according to the present invention comprises a mixture of two or more compounds selected from the group consisting of naphthenic compounds represented by formulae (1), (2), (3), (4), (5), (6) and (7).
Still furthermore, a traction drive fluid according to the present invention comprises one or more members selected from the group consisting of naphthenic compounds represented by formulae (1), (2), (3), (4), (5), (6) and (7) and (A) at least one member selected from the group consisting of a mineral oil or a synthetic oil having a molecular weight of 150 to 800.
These traction drive fluids are preferably blended with (B) a viscosity index improver. The viscosity index improver (B) is preferably a ethylene-&agr;-olefin copolymer with a number average molecular weight from 800 to 150,000 or a hydride thereof.
These traction drive fluids are preferably blended with (C) an ashless dispersant and (D) a phosphorus-containing additive.
These traction drive fluids are preferably blended with (E) a friction modifier having in its molecules an alkyl or alkenyl group having 6 to 30 carbon atoms but no hydrocarbon group having 31 or more carbon atoms.
These traction drive fluids are preferably blended with (F) a metallic detergent having a total base number of 20 to 450 mgKOH/g.
The blend of the above additives (A)-(F) with an inve
Ishida Noboru
Matsui Shigeki
Okawa Tetsuo
Shirahama Shinichi
Akin Gump Strauss Hauer & Feld L.L.P.
Griffin Walter D.
Nguyen Tam
Nippon Mitsubishi Oil Corporation
LandOfFree
Traction drive fluid does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Traction drive fluid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Traction drive fluid will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3150368