CPC H04R 7/045 (2013.01) [H04R 9/027 (2013.01); H04R 9/06 (2013.01); H04R 2440/05 (2013.01)] | 30 Claims |
1. An electrodynamic actuator (1a . . . 1c), which is designed to be connected to a backside of a plate like structure (25) or membrane (2) opposite to a sound emanating surface (S) of the plate like structure (25) or the membrane (2) and which comprises
at least one voice coil (7, 7a, 7b), which has an electrical conductor in the shape of loops running around a coil axis (A) in a loop section;
a magnet system (8) being designed to generate a magnetic field (B) transverse to the conductor in the loop section; and
an arm arrangement (14a . . . 14j) of a plurality of arms (17a . . . 17t) coupling the at least one voice coil (7, 7a, 7b) and
a) the magnet system (8) and allowing a relative movement between the voice coil (7, 7a, 7b) and said magnet system (8) in an excursion direction (C) parallel to the coil axis (A); or
b) a movable part (28) of the magnet system (8) and allowing a relative movement between the voice coil (7, 7a, 7b) and said movable part (28) of the magnet system (8) in an excursion direction (C) parallel to the coil axis (A),
wherein
the arms (17a . . . 17t) are made of a metal with a fatigue strength of at least 370 N/mm2 or an ultimate tensile strength of at least 1100 N/mm2 and wherein
each of the arms (17a . . . 17t) comprises at least two arm sections (s, s1, s2), which are arranged movable to each other and which are connected to each other by means of a damping material (18a . . . 18g) with a tensile storage modulus of 0.1-6000 MPa and a tensile loss factor of at least 0.1, each measured at room temperature of 20° C.
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