Seiko Instruments Inc

Seiko Seiki Kabushiki Kaisha

Hirotada Shimaguchi

Isamu Takehara

Masashi Ogawa

Takashi Ishida

Tadao Iwaki

Naoki Kawawada

Kaoru Kaneko

Shinichi Hayashizaki

Katsushige Konno

Tsuyoshi Kashiwada

Hiroaki Namiki

To provide an air-dynamic bearing apparatus having a radial dynamic bearing and thrust dynamic bearings by a small number of parts by using a material which is easy to fabricate and a polygon scanner motor using thereof, a rotor made of a metal is supported by a small diameter portion A provided at a front end of a stator made of a metal as a shaft portion by using an attaching hole A and a thrust plate is fixed to an end portion of the small diameter portion A to thereby constitute bearing portions, low friction metal plating layers M through M are provided to respective bearing faces of the bearing portions, thereby, a radial dynamic bearing a first thrust dynamic bearing and a second thrust dynamic bearing are formed.

Air-dynamic bearing apparatus and polygon scanner motor

A spindle motor having a simplified construction with reduced axial and radial deflection while avoiding the half whirl phenomenon includes a motor frame, a rotating shaft supporting a rotor, a stator and stator coil, a permanent magnet opposing the stator, and a liquid dynamic pressure bearing. Magnetic centers of the permanent magnet and stator coil, in the axial direction of the rotating shaft, are substantially matched. The liquid dynamic pressure bearing comprises opposing surfaces of the rotating shaft and the housing. The rotating shaft has a disk-shaped thrust bearing portion disposed in a first portion of a cylindrical hole of the housing, and a radial bearing portion disposed in a second portion of the cylindrical hole. Lubricating oil fills a space between the cylindrical hole and the thrust bearing portion and radial bearing portion, and a presser ring is pressed and fixed into a third portion of the cylindrical hole to seal the bearing. A boss portion of the rotor is fixed to a rotor supporting portion of the rotating shaft so that an inner peripheral surface of the boss portion mates with an outer peripheral surface of the rotor supporting portion. The rotating shaft has three axially-spaced portions, with the disk-shaped thrust bearing portion formed between and having a larger diameter than the other portions. A stage is provided between the thrust bearing portion and the rotor supporting portion to serve as a seat for installation of the boss portion.

Spindle motor and rotator device

A spindle motor comprises a rotational member supported by bearings for rotation about a rotational axis, a rotational body and a motor rotor mounted on the rotational member for rotation therewith, and a motor stator mounted around the motor rotor. The rotational body has an outer diameter determined so that a windage loss of the rotational body is proportional to the third power of a peripheral velocity of the rotational body and an air gap diameter of the bearings and the diameter of the motor stator are determined so that the air loss of each of the bearings and the motor rotor is proportional to the square of the peripheral velocity of each of the bearings and the motor rotor at a range of constant speed of rotation of the rotational member.

Spindle motor

A spindle motor comprises a permanent magnet having an outer diameter, an outer circumference, and a number of poles. A stator core is disposed around and spaced from the outer circumference of the permanent magnet rotor. The stator core has a yoke portion, a number of lengthwise extending and circumferentially spaced slots, and a tooth portion between each adjacent two of the slots. The slots are disposed in close proximity to the outer circumference of the permanent magnet rotor, and a width of each of the slots in a radial direction of the stator core is smaller than a width of the yoke portion and equal to or greater than 1/20 of the outer diameter of the permanent magnet rotor. A coil has two or less turns and is comprised of a conductor disposed in the slots of the stator core.

High speed spindle motor and apparatus equipped with high speed spindle

Growing community of inventors

Chiba, Japan

Hirotada Shimaguchi