Ebara Corporation

Manabu Toshimitsu

Shunichi Aiyoshizawa

Yumiko Noda

Yoshikazu Suganuma

Mamoru Suzuki

Tadashi Kataoka

Yoshio Sato

Yoichi Kanemitsu

Ryoichi Shinjo

Kazuyuki Kasahara

Daisuke Konno

Ichiro Kamiya

Sachihiko Miwa

Yoshiyuki Maruta

Tatsuo Hinata

Hiroko Fuse

Shunsuke Mimura

A drum motor for a VCR includes radial and thrust hydrodynamic bearings that are composed of a rotor-side bearing member formed by bringing a pair of first and second thrust plates into direct contact with both end surfaces of a radial bearing element and integrating them into one unit, and a stator-side bearing member in the form of a radial sleeve the inner peripheral surface and both end surfaces of which respectively cooperate with the outer peripheral surface of the radial bearing element and the mutually facing surfaces of the first and second thrust plates. A rotor magnet is secured to a rotating shaft. A motor casing is secured to the outer peripheral surface of the radial sleeve. A stator unit is secured to the motor casing. A dynamic pressure generating groove is provided on either each end surface of the radial sleeve or each of the mutually facing surfaces of the first and second thrust plates. The run-out of a rotor-side unit in both the thrust and radial directions is made extremely small and the change in the relative height of the rotor-side unit in the thrust direction due to a change of the position of the motor in which it is used is minimized.

Drum motor for VCR

A hydrodynamic bearing includes first and second thrust plates held against respective axially opposite ends of a cylindrical radial bearing member, and a cylindrical radial sleeve provided concentrically with the cylindrical radial bearing. The outer circumferential surface of the cylindrical radial bearing member and the inner circumferential surface of the cylindrical radial sleeve serve as sliding surfaces jointly making up a radial hydrodynamic bearing assembly, and the confronting surfaces of the first and second thrust plates and the end surfaces of the cylindrical radial sleeve serve as sliding surfaces jointly making up a thrust hydrodynamic bearing assembly. At least one of the sliding surfaces of the thrust hydrodynamic bearing assembly has grooves formed therein for generating a hydrodynamic pressure. At least one of the sliding surfaces of the radial hydrodynamic bearing assembly is coated with a uniform hydrogenated amorphous carbon film. At least one of the sliding surfaces of the thrust hydrodynamic bearing assembly is coated with a uniform hydrogenated amorphous carbon film.

Hydrodynamic bearing

A dynamic pressure bearing is provided with a moving side bearing member and a fixed side bearing member so as to support a rotor for rotation by generating a fluid dynamic pressure between the moving side bearing member and the fixed side bearing member. The dynamic pressure bearing includes a high-frequency exciting device for applying a high-frequency vibration to the fixed side bearing member at the time of at least one of start-up and shutdown of the rotor. In this way, both bearing members are kept almost free from contact with each other and a frictional resistance at start-up and/or shutdown is minimized.

Dynamic pressure bearing

A ceramic hydrodynamic bearing used as a radial or a thrust bearing in a spindle motor for a hard disk driver. The bearing includes a ceramic bearing base having hydrodynamic pressure generating grooves. A sliding surface of the bearing base is irradiated with an energy beam with a high energy density to remove said material, thereby forming hydrodynamic pressure generating groove, and at the same time the grooves are coated with a modification layer that is formed by melting the ceramic material that constitutes said ceramic bearing base with the energy beam and by solidifying said ceramic bearing base.

Method of cutting grooves in hydrodynamic bearing made of ceramic

Growing community of inventors

Kanagawa, Japan

Manabu Toshimitsu