| abstract |
A lubricant composition comprising a lubricating base oil, fine particles and a calcium sulfonate-based thickener, a speed reduction gear filled with the lubricant composition, and an electric power steering apparatus comprising the speed reduction gear are disclosed. It is possible to reduce the operating noise of a speed reduction gear regardless of the amount of backlash that occurs on combining a small gear and a large gear without a more complicate structure of the speed reduction gear by an action of the fine particles while preventing separation of oil by an action of the calcium sulfonate-based thickener added to the lubricant composition, and thus the noise in the inside of car generated by the electric power steering apparatus can be reduced with a low cost. |