US Patent No: 4,260,920

Number of patents in Portfolio can not be more than 2000

Multi-pole permanent magnet rotor

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Importance

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Abstract

A disk-shaped magnet attached to a rotary shaft is circumferentially segmented into a plurality of segments which are magnetized to form driving magnetic poles. A plurality of velocity detecting magnetic poles are also arranged on the disk-shaped magnet concentrically to the driving magnetic poles. The number of the velocity detecting magnetic poles is larger than the number of the driving magnetic poles to increase the frequency of an output signal of a velocity detecting coil which interlinks with the velocity detecting magnetic poles so that a response speed of a velocity control circuit is increased.

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First Claim

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Patent Owner(s)

Patent OwnerAddressTotal Patents
HITACHI, LTD.TOKYO32382
HITACHI METALS, LTD.TOKYO1178

International Classification(s)

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  • [Patents Count]

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Nakamura, Tsutomu Tokyo, JP 230 1572
Umehara, Teruo Hanyu, JP 16 287

Cited Art

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Patent Citation Ranking

Forward Cites

Patent Info (Count) # Cites Year
 
ALPS ELECTRIC CO., LTD. (4)
4,455,516 Brushless motor 20 1982
4,737,675 Brushless motor with center leads for preventing signal distortion 10 1986
4,701,649 Brushless motor with symmetrical leads for preventing signal distortion 5 1986
4,701,650 Brushless motor with phase cancelling leads for rotational speed detector pattern 8 1986
 
CANON KABUSHIKI KAISHA (3)
4,801,830 Brushless motor 24 1987
4,902,923 Motor having frequency generator 15 1988
7,312,543 Driving device 0 2006
 
CANON SEIKI KABUSHIKI KAISHA (2)
4,902,924 Brushless motor 6 1987
5,101,131 Brushless motor 9 1989
 
COMAIR ROTRON, INC. (2)
4,494,028 Integral coaxial commutation and rotor magnets and apparatus and method for making same 16 1982
4,779,069 Apparatus and method for making integral coaxial communication and rotor magnets 6 1987
 
INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE (2)
7,656,259 Precise multi-pole magnetic component 0 2005
7,884,690 Precise multi-pole magnetic component 0 2009
 
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. (2)
4,359,657 Rotation speed signal detector 15 1980
4,751,415 Brushless DC motor with means for compensating ripple torque 15 1987
 
SONY CORPORATION (2)
4,695,795 Rotation sensor with co-planar velocity and position responsive elements 19 1984
4,639,648 Three-phase brushless motor 18 1986
 
AMOTECH CO., LTD. (1)
6,064,133 Built-in stator of star-winding mechanism and method of producing the stator and BLDC motor using the same 3 1998
 
APPLIED MOTION PRODUCTS, INC. (1)
4,488,076 Tachometer assembly for magnetic motors 9 1982
 
ASAHI KASEI KOGYO KABUSHIKI KAISHA (1)
4,658,162 Printed coil unit for small size actuator 36 1985
 
ASGALIUM S.A. (1)
4,677,332 Electric motor having auxiliary portions distributed at a pitch which is an odd number sub-multiple of the pitch of active portions 31 1985
 
BUEHLER PRODUCTS, INC. (1)
4,578,606 Brushless DC electric motor and tachogenerator assembly 21 1984
 
CITIZEN ELECTRONICS CO., LTD. (1)
6,744,904 Multifunction acoustic device 4 2001
 
Clark Automotive Developments Limited (1)
4,924,125 Electric motor or alternator 55 1989
 
DYMAX CORPORATION (1)
4,479,388 Ultrasound transducer and drive system 27 1982
 
EASTMAN KODAK COMPANY (1)
5,686,769 Method of coil mounting for maximum heat transfer in brushless DC motors 2 1995
 
KUMAGAYA SEIMITSU CO., LTD. (1)
4,755,701 Brushless motor having a frequency signal generator and a pulse signal generator 12 1987
 
MITSUBISHI DENKI KABUSHIKI KAISHA (1)
4,329,636 Rotation sensor device 27 1979
 
MITSUMI ELECTRIC CO., LTD. (1)
5,631,508 Cost-saving, small-sized motor with improved stability over wide speed range 2 1994
 
PAPST LICENSING GMBH (1)
5,361,010 Tachogenerator for speed control of electric motors 5 1987
 
ROLLS-ROYCE PLC (1)
6,741,010 Rotor disc assembly having rotor rim with alternate magnets and laminated pole pieces 13 2001
 
SAMSUNG ELECTRONICS CO., LTD. (1)
5,126,613 Coil pattern of frequency generator 8 1990
 
SIEMENS AKTIENGESELLSCHAFT (1)
6,759,773 Electronically controlled electric motor provided for use in an environment containing solvents 0 2001
 
SONCEBOZ SA (1)
8,222,777 Rotary single-phase electromagnetic servo actuator comprising an actuator and a position sensor 1 2006
 
SUNONWEALTH ELECTRIC MACHINES CO., LTD. (1)
6,940,236 Parallel connected double-phase full-wave brushless dc motor 0 2003
 
TRW AUTOMOTIVE U.S. LLC (1)
6,876,167 Method and apparatus for determining the rotational rate of a rotating device 7 2003
 
U.S. PHILIPS CORPORATION (1)
4,626,727 Flat, permanent magnet electric motor 26 1984
 
Other [Check patent profile for assignment information] (3)
4,369,388 Direct current motor with non-superposed armature windings 6 1981
5,332,374 Axially coupled flat magnetic pump 19 1992
6,762,527 DC brushless motor 4 2003