Premium
Method of detecting the index position of a spindle motor for slim flexible disk drive
Author(s) -
Imai Yasuaki
Publication year - 1996
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.4391160408
Subject(s) - magnet , rotor (electric) , position (finance) , yoke (aeronautics) , rotation (mathematics) , index (typography) , inertia , position sensor , acoustics , control theory (sociology) , engineering , physics , electrical engineering , computer science , artificial intelligence , classical mechanics , fly by wire , control (management) , finance , world wide web , economics , control system
A slim flexible disk drive, which could be mounted on a hand‐held personal computer, is now under intensive study in Japan. The spindle motor for the flexible disk drive has an index‐position detecting means, an index magnet attached to the outer wall of the periphery of the rotor yoke, and a magnetic sensor which detects the magnetic flux from the index magnet. As a result, spaces for providing the index magnet and the magnetic sensor prevent the motor from being made smaller in size and reduced in thickness. This paper describes the method for detecting the index position of a spindle motor without both the index magnet and the magnetic sensor. This method detects an index position per rotation from two different kinds of frequency generating signals (main FG and sub FG) through an index‐detecting circuit. The thin spindle motor to which this index‐detecting method is applied, performed a smaller degree of rotational speed variation compared with another well‐known one without both the index magnet and the magnetic sensor. This index‐detecting method is most suitable for a less‐inertia‐thin spindle motor, and is easy to assemble.