Patent ID: 6525441
Filing Date: 2003-02-25
Classification: H02K

Abstract:
A spindle motor comprising:a rotor including a rotor case having a first wall, a shaft support transverse to the first wall and located at a center of the rotor case, at least three disc mounting guides extending outward from the first wall of the rotor case at respective holes in the first wall, spaced from each other, and arranged so that, a center defined by the disc mounting guides is coincident with the center of the rotor case, a bulge portion protruding outwardly at an outer circumferential portion of the first wall of the rotor case, and a sidewall depending from and transverse to the first wall; a disc slippage prevention sheet attached to the first wall at the bulge portion; a shaft having respective first and second ends, the first end of the shaft being installed in the shaft support; a disc chuck spring having at least one disc inner hole chucking portion for pressing radially outwardly against an inner hole of a disc mounted on the spindle motor, the disc chuck spring being disposed on the first wall of the motor case and protruding radially between a pair of the disc mounting guides; a magnet body mounted on the first wall of the rotor case extending towards, but not reaching, the disc mounting guides, and pressing the disc chuck spring against the first wall; a magnet mounted inside the rotor case; a stator base including a shaft housing containing a bearing supporting the shaft; an armature stator opposite and spaced from the magnet by a gap and disposed outside the shaft housing; and extraction preventions means in the shaft housing at the second end of the shaft for preventing extraction of the shaft from the shaft support.