Patent ID: 7293917

Claim:
A spindle motor having a hydrodynamic pressure bearing, comprising: a stator including a coil for generating an electromagnetic field when the coil is supplied with electric current to generate a rotary driving force; a rotor including magnets disposed opposite to the coil such that the rotor is rotatable relative to the stator; and a dynamic pressure generating unit including a sleeve having an upper plate disposed opposite to the rotor while being spaced a predetermined distance from the rotor, the sleeve being fixed to the stator, and at least one thrust dynamic pressure groove formed either at the upper plate of the sleeve corresponding to the rotor or at the rotor for generating dynamic pressure, wherein the inside width from a neutral radius of the thrust dynamic pressure groove to an innermost radius of the thrust dynamic pressure groove is larger than the outside width from the neutral radius of the thrust dynamic pressure groove to an outermost radius of the thrust dynamic pressure groove such that dynamic pressure at the inside width of the thrust dynamic pressure groove is higher than dynamic pressure at the outside width of the thrust dynamic pressure groove such that fluid supplied into the thrust dynamic pressure groove is guided to the outer diameter side.