Bearing member and fluid dynamic bearing device using same

摘要

A sintered metal bearing member is provided that includes radial bearing surfaces arranged at two regions spaced apart from each other in an axial direction on an inner peripheral surface. The bearing member includes radial dynamic pressure generating portions in contact with the radial bearing surfaces. The radial dynamic pressure generating portions are formed on the radial bearing surfaces. The bearing member includes a thrust bearing surface arranged on at least one of the end surfaces and a thrust dynamic pressure generating portion for generating a dynamic pressure in the lubricating oil in contact with the thrust bearing surface. The thrust dynamic pressure generating portion is formed on the thrust bearing surface. The bearing member includes a middle relief portion arranged between the radial bearing surfaces in the axial direction. The middle relief portion has a larger diameter than the radial bearing surfaces.

主权项

1. A bearing member formed of a sintered metal, comprising:
a first radial bearing surface provided on an inner peripheral surface; a second radial bearing surface provided on the inner peripheral surface, the second radial bearing surface is spaced apart to from the first radial bearing surface; a first radial dynamic pressure generating portion formed on the first radial bearing surface; a second radial dynamic pressure generating portion formed on the second radial bearing surface; end surfaces provided at both axial ends of the bearing member; a thrust bearing surface provided on at least one of the end surfaces; a thrust dynamic pressure generating portion formed on the thrust bearing surface; a middle relief portion provided between the first radial bearing surface and the second radial bearing surface in the axial direction, the middle relief portion being larger in diameter than the radial bearing surfaces; a first compression mark on the outer peripheral surface of the bearing member, the first compression mark formed in an axial region of the first radial dynamic pressure generating portion; and a second compression mark on the outer peripheral surface of the bearing member, the second compression mark formed in an axial region of the second radial dynamic pressure generating portion, wherein a first end of the first compression mark is positioned above a first end of the first radial dynamic pressure generating portion, wherein a second end of the second compression mark is positioned below a second end of the second radial dynamic pressure generating portion, wherein the first end of the first compression mark is a lower end of the first compression mark, the first end of the first radial dynamic pressure generating portion is a lower end of the first radial dynamic pressure generating portion, the second end of the second compression mark is an upper end of the second compression mark, and the second end of the second radial dynamic pressure generating portion is an upper end of the second radial dynamic pressure generating portion.