Hitachi, Ltd.

Hiroo Hiroyama

Katsutoshi Nii

Kazuhiko Kawaike

Kosho Ishizaki

Satosi Uno

Sueo Akashi

Ryoichi Kaneko

Kinpei Okano

Satoshi Uno

Katutosi Nii

A motor provided with a magnetic fluid bearing device for suppressing vibration and irregular rotation as well as preventing the magnetic fluid from being scattered from a bearing portion and the inside of the motor. The motor includes a rotor having a polygon mirror mounted thereon, a stator unit having driving coils, a rotor position detector and a rotor revolution detector attached thereto, a magnetic fluid bearing unit having a magnetic seal and a dynamic pressure seal attached thereto and a magnetic bearing. A triple seal structure for magnetic fluid which includes a first fluid seal constituted by the seals of the bearing unit, a second fluid seal constituted by a magnet of the rotor and a third fluid seal constituted by a magnet of the seal magnet is provided in the motor.

Sealed magnetic fluid bearing for polygon mirror drive motor

A motor with a magnetic fluid bearing for suppressing vibration and irregular rotation as well as preventing the magnetic fluid from being scattered from a bearing portion in the inside of the motor. The motor includes a rotor having a polygon mirror mounted thereon, a stator unit having driving coils, a rotor position detector and a rotor revolution detector attached thereto, a magnetic fluid bearing unit having a magnetic seal and a dynamic pressure seal attached thereto and a magnetic bearing. A triple seal structure for magnetic fluid which includes a first fluid seal constituted by the seals of the bearing unit, a second fluid seal constituted by a magnet of the rotor and a third fluid seal constituted by a seal of the magnetic magnet is provided in the motor.

A bearing apparatus comprises a housing formed of a non-magnetizable material and having a bottom portion, a fluid lubricating type radial bearing device provided coaxial with the housing and having a magnetic fluid sealing section and a radial bearing section, a thrust bearing device provided at the bottom portion of the housing, and a rotating shaft of a permeable material rotatably supported by the radial bearing device and thr thrust bearing device to extend through the radial bearing device. The magnetic fluid sealing section is disposed on the opening side of the housing with a predetermined spacing away from the radial bearing section whereby a space is provided between the magnetic fluid sealing section and a liquid surface of fluid lubricant filled in the radial bearing section.

Bearing apparatus

A bearing consisting of a pivot having a semi-spherical or hemi-spherical end portion formed with helical grooves and immersed in lubricating oil, and a cup bearing element also immersed in lubricating oil for supporting the pivot. A plurality of helical grooves disposed on the semi-pherical end portion are formed and arranged such that the lubricating oil is supplied under pressure to sliding surfaces of the pivot and the cup bearing element. An annular recess is formed on the intake side of the grooves.

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Hitachi, Japan

Hiroo Hiroyama