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US 6,858,567 B2Granted
Lubricating oil composition and watch using the same
AssigneeCitizen Watch Co., Ltd.
InventorYuji Akao
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AssigneeCitizen Watch Co., Ltd.
InventorYuji Akao
Estimating the term…
The first lubricating oil composition of the invention comprises a polyol ester (A) as a base oil, a specific amount of a viscosity index improver (B) and a specific amount of an anti-wear agent (C), and the second lubricating oil composition of the invention comprises a paraffinic hydrocarbon oil (F) having at least 30 carbon atoms and a specific amount of a viscosity index improver (B), so that these compositions exert effects that they enable a life of watch battery to last long, they enable a watch to operate in the temperature range of −30 to 80° C. with one kind of a lubricating oil, and they are free from change of properties over a long period of time. The third lubricating oil composition of the invention comprises an ether oil (G) as a base oil, a specific amount of an anti-wear agent (C) comprising a neutral phosphoric ester and/or a neutral phosphorous ester, and an antioxidant (E), so that this composition is free from change of properties over a long period of time and is favorable as a watch lubricating oil. The watch of the invention is a watch having a movable portion for which at least one composition selected from the above compositions is used.
A watch having a movable portion lubricated with a lubricating oil composition comprising a base oil comprising a polyol ester (A), a viscosity index improver (B) in an amount of 0.1 to 20% by weight and an anti-wear agent (C) in an amount of 0.1 to 8% by weight, said oil composition having a kinematic viscosity of not more than 1500 cSt and not less than 13 cSt at −30 to 80° C., a weight change of not more than 1.62% by weight after allowed to stand for 1000 hours at 90° C. and a total acid number of not more than 0.2 mgKOH/g, wherein:
A watch having a movable portion lubricated with a lubricating oil composition comprising a base oil comprising a paraffinic hydrocarbon oil (F) consisting essentially of an α-olefin polymer having at least 30 carbon atoms, and a viscosity index improver (B) in an amount of 0.1 to 15% by weight and an anti-wear agent (C) in an amount of 0.1 to 8% by weight, said oil composition having a total acid number of not more than 0.2 mgKOH/g, wherein:
A watch having a movable portion lubricated with a lubricating oil composition comprising a base oil comprising an ether oil (G), an anti-wear agent (C) and an antioxidant (E), wherein the anti-wear agent (C) is a neutral phosphoric ester and/or a neutral phosphorous ester and the content of the anti-wear agent (C) is in the range of 0.1 to 8% by weight, said oil composition having a total acid number of not more than 0.2 mgKOH/g.
Dependencies are inferred from the claim text.