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:
Jan. 21, 2003
Filed:
Mar. 16, 2000
Takayoshi Ozaki, Iwata, JP;
Nobuyuki Suzuki, Iwata, JP;
NTN Corporation, Osaka, JP;
Abstract
A spindle device equipped with a combined externally pressurized gas-magnetic bearing assembly, and a machining apparatus utilizing the spindle device. The spindle device is capable of accomplishing a high speed rotation with high rotational precision and includes a main shaft ( ) rotatably supported by the combined bearing assembly ( to ), an electric current detecting device ( to ) disposed in a spindle controller ( ) for detecting a current supplied to electromagnets of the combined bearing assembly ( to ). Also provided is a machining status determining device ( ) for determining the machining status in reference to the current detected by the current detecting device ( to ). The machining status may be an indication of the extent to which a machining tool is impaired.