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:
Jun. 07, 2005
Filed:
Jul. 17, 2002
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 vibration, a reduced unbalance force in the radial direction, and high torque that can be manufactured at a low cost is disclosed. The permanent magnet type three-phase stepping motor has a stator having 3L pieces of stator pole and a rotor having a permanent magnet magnetized so as to form a plurality (Nr) of N and S pole pairs, wherein a condition of 0.3≦{(Nr/π) (Ws+Wr)/(Ds+Dr)}≦0.5 is established, where L is an integer not less than 1, Nr is L (3n±1), n is an integer not less than 1, Da is an inner diameter of the stator, Dr is an outer diameter of the rotor, Ws is a width of the stator pole tooth, and Wr is a width of the rotor tooth.