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:
Aug. 29, 2000
Filed:
Jul. 02, 1996
Charles J Cheever, Beaverton, OR (US);
Frank Alton Gray, Portland, OR (US);
Mark Hazelton, Philomath, OR (US);
Johannes van Witzenburg, Lake Oswego, OR (US);
SAE Magnetics (H.K.) Ltd., Milpitas, CA (US);
Abstract
A groove forming process for forming at least one groove pattern on the outer diameter of a shaft for use in a hydrodynamic bearing of a spindle motor. First, the shaft is inserted between a pair of dies, at least one of which has a groove pattern thereon. Next, the shaft is positioned so that it is perpendicular to the groove pattern and at one end of the groove pattern. By lowering the upper die, the shaft is clasped between the dies. The shaft is then rolled in a first direction over the groove pattern by simultaneously applying pressure in a vertical direction and applying pressure in a first horizontal direction to one of the pair of dies so that the shaft rolls in the first direction. The shaft is then rolled in a second direction over the groove pattern by simultaneously applying pressure in a vertical direction and applying pressure in a second horizontal direction to one of the pair of dies so that the shaft rolls in the second direction. The steps of rolling the shaft in the first and second directions is then repeated until the groove pattern is formed on the outer diameter of the shaft. Then the shaft may be released from between the dies by raising the upper die. At this point the shaft may be removed from between the dies and inspected.