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AssigneeShin-Etsu Chemical Co., Ltd.
InventorsMasanobu Shimao, Takehisa Minowa, Masaaki Nishino
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The invention discloses an iron-based alloy sheet as a material for preparing a magnetic yoke member to build up a magnetic circuit in a hard-disk voice-coil motor as well as a magnetic yoke member made from such a sheet material. With an object to improve the magnetic circuit in respect of compactness and flatness, the iron-based alloy forming the sheet material contains inherent side elements including C, Si, Mn, P, S, Al, O and N each in a specified amount and is characterized by specified values of saturated magnetic flux density, maximum magnetic permeability and coercive force. The iron-based alloy may further contain up to 10% by weight of cobalt and/or one or a combination of adjuvant elements selected from Ti, Zr, Nb, Mo, Cr, V, Ni, W, Ta and B.
An iron-based alloy sheet as a sheet material having a thickness in the range from 0.1 mm to 5.0 mm for use as a material of a magnetic yoke to build up a magnetic circuit in a hard-disk voice-coil motor which is formed from an iron-based alloy consisting essentially of inherent side elements as follows:
An iron-based alloy sheet as a sheet material having a thickness in the range from 0.1 mm to 5.0 mm for use as a material of a magnetic yoke to build up a magnetic circuit in a hard-disk voice-coil motor which is formed from an iron-based alloy consisting essentially of cobalt in an amount not exceeding 10% by weight, inherent side elements as follows:
Dependencies are inferred from the claim text.