| 摘要 |
PURPOSE: A spindle motor is provided to improve rotation by forming a stable dynamic pressure between a shaft and a sleeve. CONSTITUTION: Grooves(21,22) are double herringbone shaped and are formed on upper and lower inner peripheral surfaces of a sleeve(20) so as to be slide supported on an outer peripheral surface of a shaft(10). A recess having a predetermined depth is formed on an inner peripheral surface on an end part side of the double herringbone shaped grooves. The sleeve(20) includes the grooves(21,22) and the recess. A hob(30) is inserted to an outer peripheral surface of the sleeve and has a disc being seated thereon. A bush(50) is inserted into an inside surface of the hob and prevents a leakage oil between a thrust bearing(40) and the sleeve(20). According to a spindle motor constructed as above, the grooves are formed from an end part of the recess which is formed on adjacent portions such that infiltration with a taper surface is not caused. Since the double herringbone shaped grooves are processed to have a predetermined depth, a stable dynamic pressure is obtained, thereby improving rotation.
|
