Permanent magnet type three-phase stepping motor

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EP 1 734 646 A8

(12)	CORRECTED EUROPEAN PATENT APPLICATION
	Note: Bibliography reflects the latest situation

(15)	Correction information:
	Corrected version no 1 (W1 A2)

(48)	Corrigendum issued on:
	21.02.2007 Bulletin 2007/08

(43)	Date of publication:
	20.12.2006 Bulletin 2006/51

(21)	Application number: 06076429.7

(22)	Date of filing: 24.07.2002

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International Patent Classification (IPC):

H02K 37/14^(2006.01)

H02K 37/18^(2006.01)

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

24.07.2001 JP 2001223010

(62)	Application number of the earlier application in accordance with Art. 76 EPC:
	02255182.4 / 1280262

(71)	Applicant: JAPAN SERVO CO. LTD.
	Chiyoda-Ku, Tokyo 101 (JP)

(72)	Inventor:
	Sakamoto, Masafumi, Japan Servo Co., Ltd. Kiryu-shi, Gunma (JP)

(74)	Representative: Powell, Timothy John et al
	Eric Potter Clarkson LLP Park View House 58 The Ropewalk Nottingham NG1 5DD Nottingham NG1 5DD (GB)


	Remarks:
	This application was filed on 14 - 07 - 2006 as a divisional application to the application mentioned under INID code 62.

(54)	Permanent magnet type three-phase stepping motor

(57) In a permanent magnet type three-phase stepping motor having a stator (1) having 3L pieces of stator pole and a rotor (2) having a permanent magnet (4, 9) 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, Ds is an inner diameter of the stator (1), Dr is an outer diameter of the rotor (2), Ws is a width of the stator pole tooth, and Wr is a width of the rotor tooth.