JP4214868B2 - Electroacoustic transducer and electronic device using the same - Google Patents

Description

  The present invention relates to an electroacoustic transducer and an electronic apparatus using the same.

  Conventionally, the structure of this type of electroacoustic transducer has a structure as shown in FIG.

  As shown in FIG. 10, a diaphragm 13 is joined to a frame 12 made of a resin material or a metal material on the outer periphery thereof. A voice coil 14 is joined to the diaphragm 13.

  The voice coil 14 includes a plate 15, a magnet 16, and a yoke 17, and is inserted in a magnetic gap of a magnetic circuit joined to the frame 12.

  Furthermore, the braking body 18 is joined so as to close the vent hole 12A provided on the back surface of the frame 12.

  The operation principle of this electroacoustic transducer is that the diaphragm 13 is vibrated by the current flowing through the voice coil 14, and the air on the back surface of the diaphragm 13 (below in FIG. 10) is supplied to the brake body 18 from the vent hole provided on the back surface of the frame. Radiated to the back through the gap. At this time, the diaphragm 13 is braked by the acoustic resistance of the braking body 18 and the amplitude at the low-band resonance frequency is suppressed.

For example, Patent Document 1 and Patent Document 2 are known as prior art document information relating to the invention of this application.
Japanese Utility Model Publication No. 63-90395 JP-A-4-312100

  In a small electroacoustic transducer, since the effective length of the voice coil 14 is short and the magnetic flux density of the magnetic circuit is small, the electromagnetic braking force is small and the resonance sharpness Q at a low resonance frequency is large. The frequency characteristic of the pressure becomes a characteristic that rises greatly at the low-band resonance frequency, which is not preferable in terms of sound quality.

  Therefore, conventionally, in order to lower the resonance sharpness Q at the low-band resonance frequency, a braking body 18 composed of a synthetic fiber nonwoven fabric or fiber mesh has been used. Since the former is made by papermaking, so-called unevenness occurs in the same plane, resulting in large variations in production lots and between production lots, resulting in variations in characteristics. In the latter case, since the fiber is thin, the acoustic resistance is small, and the resonance sharpness Q cannot be lowered sufficiently.

  Therefore, the present invention aims to stably reduce the resonance sharpness Q of the low-band resonance frequency.

  In order to achieve the above object, the present invention has the following configuration.

According to the first aspect of the present invention, there is provided a frame, a magnetic circuit composed of a plate, a magnet and a yoke held by the frame, a diaphragm having an outer peripheral portion coupled to the frame, A voice coil coupled to the lower surface of the diaphragm and inserted into the magnetic gap of the magnetic circuit, a vent formed in the frame or the magnetic circuit, and disposed at both ends of the vent, respectively, to block the vent. and a braking body which consists of a continuous foam member, the braking body is constituted by a synthetic resin compressed form a plate-like open cell foam member, by variably sequentially increase the number of cells open cell foam member relative to the lower when the air of the lower surface of the vibration plate is through emit gap braking member from the vent hole, by adjusting the ventilation sound-permeable property by sequentially increasing the acoustic resistance of the braking body, gradually diaphragm Over Yakani braking, as well as adjust the resonance突鋭degree by suppressing the amplitude of the low-range resonance frequency is obtained by preventing the contact of the yoke bottom surface of the voice coil.

  With this configuration, it is possible to finely adjust the ventilation sound permeability, and the resonance sharpness Q at the low-band resonance frequency can be stably adjusted to an appropriate value.

  Furthermore, it is possible to prevent the voice coil from hitting the inner bottom surface of the yoke.

  The invention according to claim 2 of the present invention comprises the electroacoustic transducer according to claim 1 and means for amplifying an electric signal input to the electroacoustic transducer. An apparatus excellent in quality can be realized.

As described above, the present invention forms a braking body composed of a synthetic resin obtained by compression-forming a plate-like continuous foamed member, and by varying the number of cells of the continuous foamed member to increase sequentially downward , The resonance sharpness Q at the low-band resonance frequency can be freely adjusted to an appropriate value.

  Therefore, with the braking body according to the present invention, it is possible to provide an electroacoustic transducer excellent in sound quality and quality in which a sound load necessary for sound quality can be set and thereby the bottom contact of the voice coil can be prevented.

  As described above, the present invention can provide an excellent electroacoustic transducer capable of realizing improved performance and an electronic device equipped with these, and its industrial value is very large.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
Hereinafter, the invention described in the aspect of claim 1 of the present invention will be described using the first embodiment.

  FIG. 1 is a cross-sectional view of an electroacoustic transducer according to an embodiment of the present invention.

  As shown in FIG. 1, the outer periphery of a substantially disc-shaped diaphragm 2 is joined to the inner periphery of a ring-shaped frame 1 made of a resin material or a metal material. A ring-like voice coil 3 is joined to the lower surface side of the diaphragm 2.

  The voice coil 3 includes a plate 4, a magnet 5, and a yoke 6, and is inserted into a magnetic gap of a magnetic circuit joined to the frame 1. Further, a ring-shaped braking body 7 is joined to the lower surface of the frame 1.

  Here, the braking body 7 is arranged so as to block a plurality of ventilation holes 1A provided on the back surface of the frame 1, and the material thereof is made of a continuous foam member having compressed air permeability, such as a synthetic resin. It is configured.

  The operating principle of this electroacoustic transducer is that the diaphragm 2 vibrates due to the current flowing through the voice coil 3, and the air on the lower surface of the diaphragm 2 passes through the gaps in the braking body 7 from the air holes 1 </ b> A provided in the frame 1. Radiated to the back. At this time, the diaphragm 2 is braked by the acoustic resistance (viscous resistance) by the braking body 7, and the amplitude at the low-band resonance frequency is suppressed.

  Further, the acoustic load suppresses the amplitude of the voice coil 3 and prevents the bottom surface of the yoke 6 from hitting the inner bottom surface of the voice coil 3.

  FIG. 2 shows the characteristic difference depending on the presence or absence of the braking body 7 of FIG. 1, and shows that the amplitude at the low frequency increases by about 10 DB when there is no braking body 7.

  FIG. 3 shows the measured data of the change in characteristics when the thickness of the original fabric is changed and the thickness after pressing is changed for the braking body 7 of FIG. That is, the braking body 7 is formed by compressing (pressing) a plate-like continuous foam member.

  In order of increasing thickness after pressing, A, B, C, and D are shown, with A being the thickest and D being the thinnest. The acoustic resistance also increases in this order. As a result, if the acoustic resistance increases, the braking force also increases. Therefore, it can be seen from the acoustic characteristics that peaks at low frequencies are suppressed in this order. .

  Therefore, as shown in FIG. 3, desired acoustic characteristics can be realized by changing the press thickness.

  Further, in this case, the thickness of the braking body 7 used in FIG. 1 is uniform, but the thickness may be changed partially.

  In addition, as a sheet | seat of a continuous foaming member, what used only the three-dimensional skeleton structure is used.

(Embodiment 2)
Hereinafter, the invention described in another aspect of the present invention will be described using the second embodiment of the present invention.

  FIG. 4 shows a cross-sectional view of the electroacoustic transducer in accordance with the second exemplary embodiment of the present invention, and only differences from the first exemplary embodiment will be described.

  The difference from Embodiment 1 is that the ventilation sound permeability can be adjusted by changing the number of cells or by stacking a plurality of sheets.

  In the present embodiment, an example in which the number of cells of the continuous foam is increased from the frame 1 side downward is shown. In this way, the acoustic resistance is also increased sequentially by increasing the number of cells. Therefore, since the flow velocity of the air entering the braking body 8 gradually becomes gentle, the viscous resistance can be controlled.

(Embodiment 3)
Hereinafter, the invention described in another aspect of the present invention will be described by using Embodiment 3 of the present invention.

  FIG. 7 shows a cross-sectional view of the electroacoustic transducer in accordance with the third exemplary embodiment of the present invention, and only differences from the first and second exemplary embodiments will be described.

  The difference from the first and second embodiments is that a plurality of foams 10 and 11 are arranged above and below the vent hole 1A with a gap therebetween to adjust the ventilation sound permeability.

  With this configuration, it is possible to further finely adjust the ventilation sound permeability and finely adjust the resonance sharpness Q at the low-band resonance frequency.

(Embodiment 4)
Hereinafter, the invention described in another aspect of the present invention will be described using the fourth embodiment.

  FIG. 8 shows an external view of an audio minicomponent system that is an electronic apparatus according to an embodiment of the present invention.

  As shown in FIG. 8, the electroacoustic transducer 40 of the present invention is incorporated into an enclosure 41 to constitute an electroacoustic transducer system. An audio mini-component system 44, which is an electronic device, is constituted by the enclosure 41, an amplifier 42 which is an amplifying means for an electric signal inputted to the electroacoustic transducer 40, and a player 43 which outputs a source inputted to the amplifier 42. It is composed.

  With this configuration, it is possible to improve the performance in terms of sound quality and quality of the electronic device.

  Further, although the present embodiment has been described with respect to an audio minicomponent system, it can also be applied to small mobile communication devices such as mobile phones.

(Embodiment 5)
Hereinafter, the invention described in another aspect of the present invention will be described using the fifth embodiment.

  FIG. 9 shows a sectional view of the automobile 50.

  As shown in FIG. 9, an automobile 50 is configured by incorporating an electroacoustic transducer 40 of the present invention into a rear tray.

  With this configuration, it is possible to improve performance in terms of sound quality and quality of the electroacoustic transducer 40 mounted on the automobile 50.

  The electroacoustic transducer according to the present invention can generate an appropriate braking condition at a low resonance frequency and can be applied to various acoustic devices. Furthermore, it can be applied to various electronic devices.

Sectional drawing of the electroacoustic transducer in Embodiment 1 of this invention Output sound pressure frequency characteristic diagram of electroacoustic transducer comparing with and without braking body Output sound pressure frequency characteristic diagram of electroacoustic transducer comparing thicknesses of braking bodies in embodiment 1 of the present invention Sectional drawing of the electroacoustic transducer in Embodiment 2 of this invention Sectional drawing of the electroacoustic transducer in Embodiment 2 of this invention Sectional drawing of the electroacoustic transducer in Embodiment 2 of this invention Sectional drawing of the electroacoustic transducer in Embodiment 3 of this invention The front view of the electronic device in one embodiment of this invention Sectional drawing of the vehicle in one embodiment of this invention Sectional view of a conventional electroacoustic transducer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Frame 2 Diaphragm 3 Voice coil 4 Plate 5 Magnet 6 Yoke 7 Braking body 8 Braking body 9 Braking body 10 Braking body 11 Braking body 12 Frame 13 Diaphragm 14 Voice coil 15 Plate 16 Magnet 17 York 18 Braking body (conventional product)
40 Electroacoustic transducer 41 Enclosure 42 Amplifier 43 Player 44 Mini component system 50 Automobile

Claims (2)

A magnetic circuit composed of a frame, a plate held by the frame, a magnet, and a yoke; a diaphragm having an outer peripheral portion coupled to the frame; and a lower surface side of the diaphragm; A braking body comprising a voice coil inserted into a magnetic gap of a circuit, a vent formed in the frame or the magnetic circuit, and a continuous foam member disposed at both ends of the vent and closing the vent. with the door, the brake body by constituted by synthetic resin compressed form a plate-like open cell foam member, variably sequentially increase against the lower the number of cells the continuous foam member, said vibrating plate when the lower surface of the air is a gap through radiation of the braking body from the ventilation hole, by adjusting the ventilation sound-permeable property by increasing the acoustic resistance of the damping body sequentially, before Gradually over gently brake the diaphragm, as well as adjust the resonance突鋭degree by suppressing the amplitude of the low-range resonance frequency, characterized in that to prevent contact of the yoke bottom surface of the voice coil Electroacoustic transducer. An electronic apparatus comprising: the electroacoustic transducer according to claim 1; and an amplifying unit for an electric signal input to the electroacoustic transducer.

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