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. 03, 1993
Filed:
May. 22, 1992
Masayuki Katahira, Maebashi, JP;
NSK Ltd., Tokyo, JP;
Abstract
A ball screw device with internal motors comprises a shaft provided with a ball screw groove and a ball spline groove, a ball screw nut threaded on the shaft with balls interposed therebetween, a ball spline nut threaded on the shaft with balls interposed therebetween, and direct drive motors having rotors and stators, respectively. The rotors are provided on outer circumferences of the ball screw nut and ball spline nut, respectively, so that the rotors can rotate integrally with the corresponding nuts. The stators are arranged in an opposing circumference-to-circumference relationship with outer circumferences of the rotors and are secured on an inner wall of a housing. To detect rotation angles of the nuts, rotational positions sensors are arranged close to each other between the nuts. To prevent dust from spreading into a surrounding environment such as a clean room, an air suction path can be provided in the housing to communicate gaps between the nuts and the shaft and gaps between the nuts and the corresponding drive motors to an exhaust device arranged outside the housing.