Object

Objective is to provide a grease composition for a pivot assembly and a pivot assembly bearing filled with the grease composition, and to provide a bearing apparatus as well as a drive apparatus including the bearing apparatus, which is capable of suppressing adhesion of a volatilized component to a magnetic disk or the like even when the grease composition is volatilized by application of the grease composition and the bearing, thereby suppressing occurrence of read/write errors of an HDD.

Solution

Provided are: a grease composition for a pivot assembly bearing including an aromatic ester-based base oil and a thickener, the aromatic ester-based base oil containing an aromatic ester compound having an ester group *(CO)O as a substituent on a ring, where * is a bonding site to an aromatic ring, and having an alkyl group with a total of 8 or more carbon atoms bonded to an oxygen atom of the ester group; a pivot assembly bearing filled with the grease composition for pivot assembly bearing; a bearing apparatus including the pivot assembly bearing; and a disk drive apparatus equipped with the bearing apparatus.

Object

Objective is to provide a grease composition for a pivot assembly and a pivot assembly bearing filled with the grease composition, and to provide a bearing apparatus as well as a drive apparatus including the bearing apparatus, which is capable of suppressing adhesion of a volatilized component to a magnetic disk or the like even when the grease composition is volatilized by application of the grease composition and the bearing, thereby suppressing occurrence of read/write errors of an HDD.

Solution

Provided are: a grease composition for a pivot assembly bearing including an aromatic ester-based base oil and a thickener, the aromatic ester-based base oil containing an aromatic ester compound having an ester group *(CO)O as a substituent on a ring, where * is a bonding site to an aromatic ring, and having an alkyl group with a total of 8 or more carbon atoms bonded to an oxygen atom of the ester group; a pivot assembly bearing filled with the grease composition for pivot assembly bearing; a bearing apparatus including the pivot assembly bearing; and a disk drive apparatus equipped with the bearing apparatus.

Melamine-based compounds suitable, in one embodiment, as a corrosion inhibitor for lubricating compositions and, in particular, a corrosion inhibitor for transmission fluids (manual, automatic, dual-clutch, or electric), axle fluids, differential fluids, tractor fluids, industrial gear fluids, and/or lubricating fluids for other gear-type applications. The melamine-based compounds are in the form of oil-soluble hydrocarbyl-substituted melamine derivatives comprising the reaction product of a hydrocarbyl-substituted succinic anhydride reacted with melamine at conditions effective to form a hydrocarbyl-substituted melamine polycarboxylic acid or anhydride compound.

Melamine-based compounds suitable, in one embodiment, as a corrosion inhibitor for lubricating compositions and, in particular, a corrosion inhibitor for transmission fluids (manual, automatic, dual-clutch, or electric), axle fluids, differential fluids, tractor fluids, industrial gear fluids, and/or lubricating fluids for other gear-type applications. The melamine-based compounds are in the form of oil-soluble hydrocarbyl-substituted melamine derivatives comprising the reaction product of a hydrocarbyl-substituted succinic anhydride reacted with melamine at conditions effective to form a hydrocarbyl-substituted melamine polycarboxylic acid or anhydride compound.

The invention provides a solid lubricant in the form of film containing a triazine compound or the salt thereof, such as melamine cyanurate or the like.

The invention provides a solid lubricant in the form of film containing a triazine compound or the salt thereof, such as melamine cyanurate or the like.

A water-based lubricating coating agent includes a water-soluble silicate (A) and at least one water-soluble inorganic salt (B) selected from a tungstate, a phosphate and a borate, wherein the water-soluble silicate (A) and the at least one water-soluble inorganic salt (B) are blended such that a solid content mass ratio (B)/(A) falls within a range of 0.7 to 25.

Lubricating compositions are described, the lubricating compositions comprising a base oil component and an additive component, wherein the additive component comprises a non-silicone anti-foaming agent.

Lubricating compositions are described, the lubricating compositions comprising a base oil component and an additive component, wherein the additive component comprises a non-silicone anti-foaming agent.

The invention pertains to certain (per)fluoropolyether triazine derivatives comprising at least one triazine group and at least one fluoropolyoxyalkene chain (chain R.sub.f) comprising a fluorocarbon segment having ether linkages in main chain, said chain R.sub.f comprising at least one hydroxyl group, to a method for their manufacture and to their use in lubrication, in particular for lubricating sliding or moving parts of magnetic recording media.