Patent ID: 8055010
Filing Date: 2011-11-08
Classification: H04R

Abstract:
1. Magnetic structure ( 5 , 5 ′, 5 ″, 10 ) generating a magnetic field for an ironless motor of an electrodynamic loudspeaker ( 1 ) having a mobile coil ( 2 ), wherein the magnetic structure generates a magnetic field in a gap in which the coil is arranged, said magnetic structure consisting of a stack of three magnets corresponding to one intermediate magnet ( 8 , 8 ′, 8 ″) and two top and bottom covering magnets ( 7 , 9 ) ( 7 ′, 9 ′) ( 7 ″, 9 ″) ( 11 , 12 ), the gap-circumscribing edges of said magnets being aligned and forming a straight gap border, said magnets being further located side by side, the intermediate magnet having a radial magnetic polarization, the covering magnets having the same magnetic polarization and substantially identical remanent magnetizations, characterized in that the covering magnets have a radial (