Patent ID: 8876385

Claim:
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.