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:
Sep. 24, 1996
Filed:
Sep. 30, 1993
Yoshito Oku, Osaka, JP;
Shozo Ibara, Kyoto, JP;
Shigeharu Sumi, Kyoto, JP;
Hiromasa Fujii, Kyoto, JP;
Nidec Corporation, Kyoto, JP;
Abstract
A motor having a bracket with a stator coil for generating a magnetic field and a rotor hub with rotor magnets for receiving a rotation force from the magnetic field generated by the coil. Upper and lower dynamic pressure radial bearings are formed in between the sleeve and the rotary shaft. The lower end surface of the rotary shaft is formed with a spiral groove in which a lubricating fluid is filled to form a dynamic pressure thrust bearing. The spiral groove is formed by a circular hole at the center of the shaft, and a plurality of curved grooves each curving from the circular hole to the direction opposite to the rotation direction of the shaft and gradually increasing its width toward the outer circumference of the lower end surface of the shaft without reaching the circumference. The spiral groove functions to move the lubricating fluid outward in the radial direction from the center of the shaft, when the shaft rotates.