Hydraulic system using an improved antiwear hydraulic fluid
AssigneeChevron Chemical Company
InventorsStuart H. Brown, Todd Brookhart
Life of this patent
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Abstract
A hydraulic system containing a piston-type pump having wear surfaces containing copper or a copper alloy, and, optionally, a vane-type pump having wear surfaces containing steel, uses an antiwear hydraulic fluid having an oil of lubricating viscosity and minor amounts of zinc dithiophosphate and a wear moderating agent. The wear moderating agent can be aliphatic polyol esters, boric acid derivatives of aliphatic polyol esters, aliphatic amines, aliphatic polyamines, aliphatic imidazolines, or mixtures of any combination thereof. The aliphatic groups of the wear moderating agent are substantially straight-chained, and the wear moderating agent contains at least ten carbon atoms.
Claims16
In a hydraulic system containing a piston-type pump having wear surfaces containing copper or a copper alloy, and a vane-type pump having wear surfaces containing steel, the improvement comprising using, in said hydraulic system, an anti-wear hydraulic fluid useful in both types of pumps, said anti-wear hydraulic fluid comprising:
- (a) a major amount of an oil of lubricating viscosity;
- (b) a minor amount of at least one metal dithiophosphate;
- and
- (c) a minor amount of a wear moderating agent selected from the group consisting of:
- (1) aliphatic polyol esters, boric acid derivatives thereof, and mixtures thereof;
- (2) a nitrogen-containing compound selected from the group consisting of aliphatic amines, aliphatic polyamines, and mixtures thereof;
- and
- (3) mixtures of (1) and (2);
- wherein the aliphatic groups are substantially straight-chained, and wherein the wear moderating agent contains at least ten carbon atoms.
In a hydraulic system containing a piston-type pump having wear surfaces containing copper or a copper alloy, and a vane-type pump having wear surfaces containing steel, the improvement comprising using, in said hydraulic system, an anti-wear hydraulic fluid useful in both types of pumps, wherein said anti-wear hydraulic fluid is produced by the method comprising blending the following components:
- (a) a major amount of an oil of lubricating viscosity;
- (b) a minor amount of at least one metal dithiophosphate;
- and
- (c) a minor amount of a wear moderating agent selected from the group consisting of:
- (1) aliphatic polyol esters, boric acid derivatives thereof, and mixtures thereof;
- (2) a nitrogen-containing compound selected from the group consisting of aliphatic amines, aliphatic polyamines, and mixtures thereof;
- and
- (3) mixtures of (1) and (2);
- wherein the aliphatic groups are substantially straight-chained, and wherein the wear moderating agent contains at least ten carbon atoms.
In a hydraulic system containing a piston-type pump having wear surfaces containing copper or a copper alloy, and a vane-type pump having wear surfaces containing steel, the improvement comprising using, in said hydraulic system, an anti-wear hydraulic fluid useful in both types of pumps, wherein said anti-wear hydraulic fluid is produced by the method comprising
- (a) blending the following components to form a concentrate:
- (1) a minor amount of a diluent oil;
- (2) at least one metal dithiophosphate;
- and
- (3) a wear moderating agent selected from the group consisting of:
- (i) aliphatic polyol esters, boric acid derivatives thereof, and mixtures thereof;
- (ii) a nitrogen-containing compound selected from the group consisting of aliphatic amines, aliphatic polyamines, and mixtures thereof;
- and
- (iii) mixtures of (i) and (ii);
- wherein the aliphatic groups are substantially straight-chained, and wherein the wear moderating agent contains at least ten carbon atoms;
- and
- (b) blending the concentrate formed in the step (a) with a major amount of an oil of lubricating viscosity.
Dependencies are inferred from the claim text.