Sony Corporation

Mitsuo Nishikawa

Shigeki Yamazaki

Yoshiyuki Noguchi

Souichi Murakami

Toshio Saotome

A flat type DC motor applicable for disc drive of an electronic still camera in which vibrations of the rotor axle are prevented without increasing manufacturing costs by providing the magnetic field between the stator and rotor to by asymmetrical so that the magnetic attracting force of the rotor to the stator is also asymmetrical. The asymmetrical attracting force causes the axle of the rotor to be urged in the same radial direction relative to the axle bearing in the stator, thus, movements of the axle in radial directions in the clearance between the axle and bearing of the stator are eliminated and the rotor rotates without vibrating.

Structure of a flat-type brushless DC motor

A disc spindle motor of the axial air-gap type includes a record disc chucking portion having a center boss with a disc support surface formed around the center boss. A magnet is arranged adjacent and beneath the disc support surface to hold a magnetic central core of the record disc against the support surface. The rotor of the spindle motor has a rotor magnet affixed to a rotor yoke and facing the stator coils. The center boss and disc support of the disc chucking portion and the rotor yoke of the rotor are all integrally formed in one piece by molding a resin, such as nylon-6, with a magnetic powder, such as iron powder.

Growing community of inventors

Kanagawa, Japan

Mitsuo Nishikawa