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:
Dec. 05, 2006
Filed:
Apr. 28, 2005
Masafumi Sakamoto, Gunma, JP;
Masafumi Sakamoto, Gunma, JP;
Japan Servo Co., Ltd., Tokyo, JP;
Abstract
A permanent magnet type three-phase stepping motor that is simple in construction, with reduced vibration, a reduced unbalanced force in the radial direction, and high torque that can be manufactured at a low cost. The permanent magnet type three-phase stepping motor has a stator and a rotor arranged concentrically with the stator and with an air gap therebetween, said stator having three stator poles, and stator windings of three-phase each wound around each stator pole, each of said stator poles having m pieces of stator pole tooth, said rotor having two split rotor elements, a permanent magnet held between the rotor elements and magnetized so as to form N and S poles in the axial direction thereof, and a plurality (Nr) of small rotor teeth formed at a regular pitch on the outer peripheral surface of each of said rotor elements, said two split rotor elements being circumferentially shifted from each other by a ½ pitch of the small rotor teeth, wherein a pitch of the stator pole teeth is smaller than the pitch of the small rotor teeth, m is an integer and (Nr±2)/3, Nr is 3n±1, n is an integer not less than 1, and k is an integer not less than 1 and not more than 4.