Fluid dynamic bearing oil composition for hard disk drive motor

Abstract

There is provided a fluid dynamic bearing oil composition for a hard disk drive motor. The fluid dynamic bearing oil composition includes 0.5 to 1.0 parts by weight of a defoaming agent based on 100 parts by weight of the total composition. The bubbles in the fluid dynamic bearing oil may be removed by adding a small amount of defoaming agent to the fluid dynamic bearing oil composition for a hard disk drive motor.

1 . A fluid dynamic bearing oil composition for a hard disk drive motor, comprising 0.5 to 1.0 parts by weight of a defoaming agent based on 100 parts by weight of the total composition. 
     
     
         2 . The fluid dynamic bearing oil composition of  claim 1 , wherein the defoaming agent is at least one selected from the group consisting of silicone-based materials and non-silicone-based materials. 
     
     
         3 . The fluid dynamic bearing oil composition of  claim 2 , wherein the silicone-based material is at least one selected from the group consisting of emulsion-type, compound-type, oil-type, and powder-type materials. 
     
     
         4 . The fluid dynamic bearing oil composition of  claim 2 , wherein the non-silicone-based material is at least one selected from the group consisting of mineral oils and polyalkylene glycols. 
     
     
         5 . The fluid dynamic bearing oil composition of  claim 1 , wherein the defoaming agent includes at least one selected from the group consisting of higher fatty alcohols, higher fatty acids, higher fatty acid esters, higher fatty amines, higher fatty acid amides, higher fatty ethers, and silicone oils. 
     
     
         6 . The fluid dynamic bearing oil composition of  claim 1 , wherein the defoaming agent is a foam suppressor. 
     
     
         7 . The fluid dynamic bearing oil composition of  claim 1 , wherein the fluid dynamic bearing oil composition contains a basic oil having an ester as a main component thereof.