Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing boron
Patent
1995-09-21
1996-11-05
Howard, Jacqueline V.
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic compound containing boron
508192, 508195, 508198, C10M11102, C10M11104
Patent
active
055714455
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to gear oils, and more particularly to manual transmission gear oils that have the capability of sharply reducing if not eliminating clashing of gears under low temperature conditions.
TECHNICAL PROBLEM SOLVED BY THE INVENTION
A "cold-clash" gear problem has recently been experienced by at least one well-known commercial manufacturer of manual transmissions for passenger cars and other vehicles. When the transmission is cold, as during initial vehicle operation after exposure to the cold during winter months in cold climatic regions of the world, the transmission does not operate properly. The operator usually finds it necessary to exert excessive force upon the gear shift lever and in addition there can be and often is a pronounced clashing of the gears during the shifting operations. While the source of the problem is not known with certainty, it is a real world problem crying for a solution. As a matter of fact, even use of the best current factory-fill synthetic 75W-90 GL-4 gear oil fails to alleviate this perplexing problem.
THE INVENTION
This invention provides an effective solution to the cold-clash problem.
In accordance with this invention an essentially metal-free and essentially halogen-free, boron-containing gear oil lubricant composition is provided which comprises: ester of an aliphatic dicarboxylic acid having a maximum pour point of about -55.degree. C. and a maximum kinematic viscosity at 100.degree. C. of about 4 cSt (mm.sup.2 /sec); (2) hydrogenated poly-.alpha.-olefin oligomer having a kinematic viscosity at 100.degree. C. of about 40 cSt; (3) at least one hydrogenated poly-.alpha.-olefin .alpha.-oligomer having a kinematic viscosity at 100.degree. C. in the range of about 4 to about 8 cSt; and (4) hydrogenated poly-.alpha.-olefin oligomer having a kinematic viscosity at 100.degree. C. of about 2 cSt, in proportions such that for each 100 parts by weight of (2) there are about 10 to about 40 parts by weight of (1), about 3 to about 25 parts by weight of (3), and about 11 to about 30 parts by weight of (4); about 0.7 to about 7 wt % of at least one oil-soluble organic sulfur-containing antiwear and/or extreme pressure agent having a sulfur content of at least about 20% by weight; phosphorus-containing antiwear and/or extreme pressure agent; corrosion inhibitor; inhibitor; and dispersant; composition, said composition being still further characterized in that the sulfur:phosphorus weight ratio of said composition is in the range of about 8:1 to about 35:1, in that the boron content of said composition is in the range of about 0.0025 to about 0.07 wt %, and in that the kinematic viscosity of said composition is in the range of about 13 to about 15 cSt (and preferably in the range of about 13.5 to about 14.5 cSt) at 100.degree. C.
Preferably, the dialkyl ester is a dialkyl adipate, a dialkyl sebacate, or a mixture thereof.
Pursuant to one embodiment of this invention the base oil of the above composition consists essentially of a blend of (1) di(2-ethylhexyl)sebacate; (2) hydrogenated poly-.alpha.-olefin oligomer having a kinematic viscosity at 100.degree. C. of about 40 cSt; (3) hydrogenated poly-.alpha.-olefin oligomer having a kinematic viscosity at 100.degree. C. of about 8 cSt; and (4) hydrogenated poly-.alpha.-olefin oligomer having a kinematic viscosity at 100.degree. C. of about 2 cSt, in proportions such that for each 100 parts by weight of (2) there are about 24 to about 40 parts by weight of (1), about 3 to about 12 parts by weight of (3), and about 11 to about 20 parts by weight of (4).
Use of a composition of this invention has been found to sharply reduce if not totally eliminate the cold-clash problem. Thus another embodiment of this invention is the method of alleviating the problem of cold-clashing of gears in a manual transmission upon, during and shortly after exposure to low temperature climatic conditions, which method comprises providing as the lubricant in said transmission a gear oil composition of this invention. Still a
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Hartley Rolfe J.
Srinivasan Sanjay
Ethyl Corporation
Howard Jacqueline V.
Rainear Dennis H.
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