Lubricating oil composition for hydrodynamic bearing and hdd motor using the same

Abstract

There is provided a lubricating oil composition for a hydrodynamic bearing including: 95 to 99 wt % of an ester-based base oil; and 1.0 to 5.0 wt % of mixed oil containing at least two kinds of ester-based oils different from the ester-based base oil. According to the present invention, a hard disk drive (HDD) motor is manufactured using the lubricating oil composition for a hydrodynamic bearing having a low viscosity, a small evaporation loss, and improved oxidation stability at a room temperature, whereby the impact resistance and low-temperature operation stability of the hydrodynamic bearing motor may be improved.

What is claimed is: 
     
         1 . A lubricating oil composition for a hydrodynamic bearing comprising:
 95 to 99 wt % of an ester-based base oil; and   1.0 to 5.0 wt % of mixed oil containing at least two kinds of ester-based oils different from the ester-based base oil.   
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the ester-based base oil is at least one selected from a group consisting of dioctyl adipate (DOA), heptylnonyl adipate, 3-methyl-1,5-pentandiol(dinonanoate), and neopentylglycol ester. 
     
     
         3 . The lubricating oil composition of  claim 1 , wherein the mixed oil containing at least two kinds of ester-based oils different from the ester-based base oil includes at least one selected from a group consisting of dioctyl sebacate (DOS), dioctyl azelate (DOZ), and diisodecyl adipate (DIDA). 
     
     
         4 . The lubricating oil composition of  claim 1 , further comprising at least one additive selected from a group consisting of an antioxidant, an anti-abrasion agent, an anti-corrosion agent, an extreme-pressure additive, a viscosity index improver, an anti-static agent, and a deactivator. 
     
     
         5 . The lubricating oil composition of  claim 4 , wherein the additive includes an anti-oxidant, 2,2′-methylene-bis(4-methyl-6-tert-butylphenol). 
     
     
         6 . The lubricating oil composition of  claim 4 , wherein the additive includes a metal anti-oxidant, barium diphenylamine-4-sulfonate. 
     
     
         7 . The lubricating oil composition of  claim 4 , wherein the additive includes an internal pressure preventing agent, tricresyl phosphate. 
     
     
         8 . A hard disk drive (HDD) motor using a lubricating oil composition for a hydrodynamic bearing, the lubricating oil composition containing:
 95 to 99 wt % of an ester-based base oil; and   1.0 to 5.0 wt % of the mixed oil containing at least two kinds of ester-based oils different from the ester-based base oil.   
     
     
         9 . The hard disk drive (HDD) motor of  claim 8 , wherein the ester-based base oil is at least one selected from a group consisting of dioctyl adipate (DOA), heptylnonyl adipate, 3-methyl-1,5-pentandiol(dinonanoate), and neopentylglycol ester. 
     
     
         10 . The hard disk drive (HDD) motor of  claim 8 , wherein the mixed oil containing at least two kinds of ester-based oils different from the ester-based base oil includes at least one selected from a group consisting of dioctyl sebacate (DOS), dioctyl azelate (DOZ), and diisodecyl adipate (DIDA). 
     
     
         11 . The hard disk drive (HDD) motor of  claim 8 , wherein the lubricating oil composition further includes at least one additive selected from a group consisting of an antioxidant, an anti-abrasion agent, an anti-corrosion agent, an extreme-pressure additive, a viscosity index improver, an anti-static agent, and a deactivator. 
     
     
         12 . The hard disk drive (HDD) motor of  claim 11 , wherein the additive includes an anti-oxidant, 2,2′-methylene-bis(4-methyl-6-tert-butylphenol). 
     
     
         13 . The hard disk drive (HDD) motor of  claim 11 , wherein the additive includes a metal anti-oxidant, barium diphenylamine-4-sulfonate. 
     
     
         14 . The hard disk drive (HDD) motor of  claim 11 , wherein the additive includes an internal pressure preventing agent, tricresyl phosphate.