The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 12, 1996
Filed:
Sep. 01, 1993
Katsutoshi Nii, Hitachi, JP;
Takeshi Nakajima, Hitachi, JP;
Ichiro Hashimoto, Hitachi, JP;
Satosi Uno, Hitachi, JP;
Sueo Akashi, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A motor has a rotor mounted on a stator to rotate about a rotation axis. The rotor is driven due to the interaction of a drive coil on the stator and a permanent magnet on the rotor. A magnetic thrust bearing, having permanent magnets on the stator and rotor, applies a radial thrust force. The radially outer surface of the permanent magnet on the rotor abuts a part of the rotor, so as to resist forces on the permanent magnet at high speed rotation or due to thermal deformation. The permanent magnets on the stator and the rotor may be axially offset by an offset of not more than 1/4 the axial length of the permanent magnets, or the axial length of the longer of the permanent magnets if they have different axial lengths. This generates an axial thrust at the thrust bearing, which counteracts the attractive force between the permanent magnet and the drive coil, and also the weight of the rotor.