Abstract: An electroacoustic transducer 1 includes a base 24 made of a magnetic material; a magnetic core 22 made of a magnetic material and upstanding on the base 24; a diaphragm 20 made of a magnetic material and spaced from a leading end of the magnetic core; a magnetic field generating member 25 cooperating with the base 24, the magnetic core 22 and the diaphragm 20 to constitute a magnetic circuit, for supplying a static magnetic field; a coil 23 placed around the magnetic core, for supplying an oscillating magnetic field to the magnetic circuit. The magnetic field generating member 25 constitutes a multiplex ring structure in which a magnet 25a and a support ring 26 are integrated together, whose faces opposing the diaphragm 20 have respectively magnetic poles of the same polarity.

Abstract: An electroacoustic transducer adapted to be mounted on a printed circuit board in which a coil spring is accommodated and supported in a cylindrical recess of a frame while it is fixed to neither a terminal plate nor the frame. Particularly, a protruding pin of the coil spring is passed through a though hole of the terminal plate to allow a leading portion of the protruding pin to be hooked thereon. When the electroacoustic transducer is mounted on the printed circuit board, any horizontal displacement between the compressed spring and the printed circuit board would not cause stress concentration on the coil spring since the coil spring is onlly horizontally shifted in the cylindrical recess until a coil portion of the coil spring hits against the wall of the cylindrical recess.

Abstract: An electroacoustic transducer adapted to be mounted on a printed circuit board in which a coil spring is accommodated and supported in a cylindrical recess of a frame while it is fixed to neither a terminal plate nor the frame. Particularly, a protruding pin of the coil spring is passed through a though hole of the terminal plate to allow a leading portion of the protruding pin to be hooked thereon. When the electroacoustic transducer is mounted on the printed circuit board, any horizontal displacement between the compressed spring and the printed circuit board would not cause stress concentration on the coil spring since the coil spring is onlly horizontally shifted in the cylindrical recess until a coil portion of the coil spring hits against the wall of the cylindrical recess.

Abstract: An electroacoustic transducer 1 is provided with a diaphragm 20 which is made of a magnetic material, and to which a magnetic piece 21 is fixed; a magnetic core 22 which is placed in proximity to the diaphragm 20; a coil 23 which supplies an oscillating magnetic field to the magnetic core 22; a housing 10 which accommodates the diaphragm 20, the magnetic core 22, and the coil 23, and which has a sound release opening 11 in a top plate opposed to the diaphragm 20, the sound release opening being larger than the magnetic piece 21. A beam portion 12 is formed integrally with the housing 10 which extends from a peripheral portion of the sound release opening 11 to another peripheral portion passing above the magnetic piece 21. A gap Ga between the diaphragm 20 and the magnetic core 22, and a gap Gb between the magnetic piece 21 and the beam portion 12 satisfy relationships of Ga≦Gb≦5Ga.

Abstract: An electroacoustic transducer 1 is provided with a diaphragm 20 which is made of a magnetic material, and to which a magnetic piece 21 is fixed; a magnetic core 22 which is placed in proximity to the diaphragm 20; a coil 23 which supplies an oscillating magnetic field to the magnetic core 22; a housing 10 which accommodates the diaphragm 20, the magnetic core 22, and the coil 23, and which has a sound release opening 11 in a top plate opposed to the diaphragm 20, the sound release opening being larger than the magnetic piece 21. A beam portion 12 is formed integrally with the housing 10 which extends from a peripheral portion of the sound release opening 11 to another peripheral portion passing above the magnetic piece 21. A gap Ga between the diaphragm 20 and the magnetic core 22, and a gap Gb between the magnetic piece 21 and the beam portion 12 satisfy relationships of Ga≦Gb≦5Ga.

Abstract: An electroacoustic transducer 1 includes a base 24 made of a magnetic material; a magnetic core 22 made of a magnetic material and upstanding on the base 24; a diaphragm 20 made of a magnetic material and spaced from a leading end of the magnetic core; a magnetic field generating member 25 cooperating with the base 24, the magnetic core 22 and the diaphragm 20 to constitute a magnetic circuit, for supplying a static magnetic field; a coil 23 placed around the magnetic core, for supplying an oscillating magnetic field to the magnetic circuit. The magnetic field generating member 25 constitutes a multiplex ring structure in which a magnet 25a and a support ring 26 are integrated together, whose faces opposing the diaphragm 20 have respectively magnetic poles of the same polarity.

Abstract: An electroacoustic transducer 1 has: a base 24 made of magnetic material; a magnetic core 22 provided erectly on the base 24; a diaphragm 20 supported so as to separate from a forward end of the magnetic core with an air gap therebetween; a magnet 25 constituting a magnetic circuit together with the base 24, the magnetic core 22 and the diaphragm 20 so as to apply a magnetostatic field to the magnetic circuit; a coil 23 for applying an oscillating magnetic field to the magnetic circuit; and a support ring 26 for supporting the diaphragm 20; wherein all the members constituting the electroacoustic transducer are enclosed in the base 24 and a casing 10; tapered coil spring terminals 40 are fixed to a wiring board 30 attached to the bottom surface of the base 24; and a skirt portion 13 of the casing 10 abuts against a circuit board 51 in the condition that the electroacoustic transducer 1 is mounted on the circuit board 51, so that the spring terminals 40 are prevented from being compressed beyond necessity.

Abstract: The invention provides an electroacoustic transducer capable of preventing degradation in its acoustic performance as a result of the reflow soldering process applied. With the electroacoustic transducer, variation in the minimum resonance frequency Fo of a diaphragm is restrained, stabilizing the acoustic performance by causing a decrease in the minimum resonance frequency Fo of the diaphragm due to irreversible demagnetization of the magnet caused by the reflow soldering temperatures to cancel out an increase in the minimum resonance frequency Fo of the diaphragm due to thermal contraction of a holder member caused by the reflow soldering temperatures.

Abstract: The present invention provides an electroacoustic transducer which realizes an optimum characteristic thereof utilizing heat caused by reflow soldering without being influenced by the same heat. The electroacoustic transducer includes a magnetic driving portion composed of a base, a core provided upright on the base and a coil wound around the core, wherein a height of the coil at the manufacturing time is set lower by a height which corresponds to thermal expansion of the coil in reflow soldering, and a projection length of the core exposed from the coil at the manufacturing time is set larger by the height which corresponds to thermal expansion of the coil in reflow soldering.

Abstract: The present invention provides an electroacoustic transducer and a method of fabricating the same, employing a lead frame to integrally form a plurality of component parts, thus reducing the number of individual component parts, and improving assembly efficiency. The electroacoustic transducer comprises a base, a yoke fixed to the base, a core, a coil wound around the core, magnet surrounding the coil, a support ring surround the magnet, a vibrating plate supported on the support ring, lead terminals fixed to the base, and a case having a sound emitting cylinder and joined to the base so as to cover those components. A gap is formed between the core and the diaphragm. The diaphragm, the gap, the core, the yoke and the magnet form a closed magnetic path. The coil drives the diaphragm for vibration when energized. The yoke and the lead terminals are integrally formed of a common metal material such as the lead frame. The core may be integrally formed with the yoke of the lead frame.

Abstract: The present invention provides a fabrication method of an electroacoustic transducer capable of simplifying an assembling process on a lead frame and realizing an automatic assembly. The method comprises steps of forming pole piece portions, forming a lead frame having a plurality of base forming areas thereon, each of the areas having lead terminals formed therein, forming bases of a synthetic resin on the lead frame by molding so that the pole piece portions are embedded in the bases, mounting a coil on the pole piece portions embedded in the bases, disposing a support ring and a magnet so as to surround the coil, and placing a diaphragm on the support ring to be held thereby, connecting opposite ends of the coil to the lead terminals, cutting off the lead terminals from the lead frame, putting cases on and fixedly joining the same to the bases, and subjecting the cut lead terminals to a forming process.