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:
Sep. 23, 2025
Filed:
Sep. 08, 2023
Yamaha Corporation, Hamamatsu, JP;
Takahiro Terada, Hamamatsu, JP;
Yukio Wakui, Iwata, JP;
Tsunenori Sano, Hamamatsu, JP;
Masao Noro, Hamamatsu, JP;
YAMAHA CORPORATION, Hamamatsu, JP;
Abstract
An object of the present invention is to provide a magnetic circuit for an acoustic transducer, the magnetic circuit enabling peeling of the surface of a member formed by compression-molding a soft magnetic composite material to be suppressed. The present invention is a magnetic circuit for an acoustic transducer, the magnetic circuit including: a yoke; a magnet; and a top plate, wherein the yokeincludes a bottom surface portionand a pole pieceprovided perpendicular to the bottom surface portion, the magnetand the top plateare provided in that order on the bottom surface portion, a magnetic gapin which a voice coilis disposed is formed between the pole pieceand the top plate, at least one of the pole pieceand the top plateincludes: a composite material partin a position facing the magnetic gap; and a protective layercovering at least a surface of the composite material part, the composite material partis formed from a soft magnetic composite material, and the material of the protective layerdiffers from the soft magnetic composite material.