A loudspeaker includes the following components: a frame ( 5 ) that has a magnetic circuit ( 4 ) including a magnetic gap ( 4 a ) therein; and a diaphragm ( 6 ) that is bonded to a voice coil ( 7 ) fitted into the magnetic gap ( 4 a ) in the center thereof, and to the periphery of the frame ( 5 ) along the outer periphery thereof. The magnetic circuit ( 4 ) includes a yoke ( 1 ), a magnet ( 2 ), and a top plate ( 3 ). Tongue-shaped flanges ( 1 a ) are disposed at a substantially equidistant spacing in three positions to protrude from the top end face of the yoke ( 1 ). The total area of these tongue-shaped flanges ( 1 a ) in the three positions does not exceed a half of the total area corresponding to the flange part without flanges ( 1 a ). The frame ( 5 ) also includes engaging parts ( 5 a ) each for receiving one of the tongue-shaped flanges ( 1 a ) therein.
1. A loudspeaker comprising:
a magnetic circuit having a magnetic gap;
a frame made of resin and having the magnetic circuit joined to a bottom surface of the frame; and
a diaphragm joined to a voice coil fitted into the magnetic gap in a center thereof, and to a periphery of the frame along an outer periphery thereof,
wherein the magnetic circuit includes a cylindrical socket-shaped yoke, a magnet disposed in the yoke, and a top plate disposed on the magnet;
tongue-shaped flanges are disposed at a substantially equidistant spacing in three positions to partially protrude in an outer circumferential direction from a top end face of the yoke so that a total area of these tongue-shaped flanges in the three positions does not exceed a half of a total area corresponding to a flange part without the flanges; and
the frame includes thereon engaging parts each for receiving a corresponding one of the tongue-shaped flanges provided in the yoke while the top end face of the yoke is in contact with the bottom surface of the frame.
2. The loudspeaker of claim 1 , wherein
each of the engaging parts includes an inverted L-shaped columnar rib integrally provided on the bottom surface of the frame so that a tip of the rib is in contact with a backside of a corresponding one of the tongue-shaped flanges; and
parallel clearances, respectively formed between the tips of the ribs and the bottom surface, sandwich the tongue-shaped flanges.
3. The loudspeaker of claim 1 , wherein rotation stoppers are provided on the frame so that one of end faces of each of the tongue-shaped flanges is in contact with a corresponding one of the rotation stoppers while the tongue-shaped flanges are fitted into the engaging parts.
4. The loudspeaker of claim 1 , wherein each of the tongue-shaped flanges includes a protrusion on a backside thereof, and the engaging parts include thereon recesses each for receiving a corresponding one of the protrusions.
5. The loudspeaker of claim 4 , wherein each of the protrusions includes, on one circumferential side thereof, a gentle slope leading to the backside of a corresponding one of the tongue-shaped flanges, and, on another circumferential side thereof, a steep slope leading to the backside of the tongue-shaped flange.
6. The loudspeaker of claim 1 , wherein an adhesive is used to join the engaging parts and the tongue-shaped flanges to each other.