Patent ID: 6538354
Filing Date: 2003-03-25
Classification: G11B

Abstract:
A spindle motor including a base, a spindle secured to the base and extending therefrom, the spindle having upper and lower end portions, a rotor hub having a vertical bore through a central portion thereof, the vertical bore having upper and lower end portions, a bearing assembly interposed between the spindle and the bore of the rotor hub,a labyrinth seal formed between the spindle and the rotor hub, and a plurality of flat sealing plates disposed between corresponding end portions of the spindle and the vertical bore of the rotor hub, the flat sealing plates spaced axially by small gaps therebetween, alternate ones of said flat sealing plates being secured to said vertical bore of the rotor hub and to said spindle, respectively; said flat sealing plates secured to said vertical bore having an outer peripheral portion secured to said vertical bore and an inner peripheral portion spaced by a slight radial gap from said spindle; said flat sealing plates secured to said spindle having an inner peripheral portion secured to said spindle and an outer peripheral portion spaced by a slight radial gap from said vertical bore, wherein: said spindle comprises a stepped structure at an end portion thereof, said end portion having a smaller diameter than another portion of said spindle adjacent thereto and forming a step therebetween; and at least one of said flat sealing plates secured to said spindle is secured thereto at said step.