JP5055045B2 - Microphone - Google Patents

Description

  The present invention relates to a microphone, and more particularly, to a buffer means (shock mount structure) that elastically supports a microphone unit on one end side of a microphone housing.

  Among the microphones, in particular, in a hand microphone (hand-held type) microphone, noise is generated by vibration when a speaker rubs or holds the microphone casing (microphone grip) with, for example, a finger. This is called vibration noise or handling noise.

  In general, with respect to microphones having diaphragms having the same surface density, vibration noise of low frequency components increases in the order of omnidirectional → unidirectional → bidirectional. In addition, a dynamic (dynamic) microphone has a heavier diaphragm than a condenser or ribbon microphone, and vibration noise is likely to occur.

  Therefore, in order to reduce vibration noise, in the dynamic microphone, the microphone unit is elastically supported on the microphone housing via a buffering means made of a rubber material (see, for example, Patent Documents 1 and 2). In the field of microphones, the elastic support is sometimes referred to as a shock mount. Shock mounts are also applied to some models such as condenser microphones.

  In the design of the shock mount, the vibration noise is reduced by setting the resonance frequency of the microphone unit to a frequency lower than the low frequency reproduction limit of the microphone.

  By softening the rubber elasticity of the shock mount, vibration noise can be reduced more effectively. Not only does it hit the windshield and a loud impact sound is generated, but in the worst case, the microphone unit may be damaged.

  The impact sound emitted from the microphone unit can be reduced, for example, by attaching a cushioning material such as felt or sponge to the corner of the microphone unit or the inner surface of the bed case. Is gradually crushed, and in the worst case, it is broken, so that the effect of the cushion is lost.

Japanese Utility Model Publication No. 2-137195 JP-A-5-244678

  Accordingly, an object of the present invention is to reduce a vibration noise during normal use, and to provide a microphone having a buffer unit that can prevent excessive displacement of the microphone unit when subjected to a strong impact such as a drop impact. It is to provide.

To solve the above problems, the present invention is, in one end of the microphone housing, the microphone comprising resiliently supported via the buffer means a microphone unit having an acoustic-electric converter, as the buffer means, the pair A damper in which an electrorheological fluid is disposed between the electrodes is used, and a piezoelectric element that generates electric power by an impact applied to the microphone casing is provided in the microphone casing, and the piezoelectric element, each electrode, Are electrically connected via lead wires, and the damper is fitted with an outer cylindrical portion fitted to an inner peripheral surface on one end side of the microphone casing and a rear end portion of the microphone unit. A cylindrical support ring made of an elastic material having a sealed space inside, and the outer cylindrical part side in the support ring With each of the above electrodes and the inner cylindrical portion are arranged, is characterized in that said electrorheological fluid is sealed within said supporting ring.

  In the present invention, the microphone unit is preferably an electrodynamic microphone unit. In this case, the inside of the support ring is closed by the bottom plate on the side opposite to the support surface of the support ring. It can be a back air chamber (back cavity).

  The electrorheological fluid is also referred to as ER fluid (Electro Rheological fluid), and is a reversible fluid that has a low viscosity when no voltage is applied but the viscosity instantaneously increases when a voltage is applied.

  Therefore, according to the present invention, when an impact is applied to the microphone housing, the piezoelectric element generates electric power due to the impact, the voltage is applied to the electrorheological fluid, and the viscosity of the electrorheological fluid instantaneously increases. Excessive displacement of the microphone unit is suppressed and collision with the head case is prevented.

  On the other hand, during normal use, almost no voltage is applied to the electrorheological fluid and the electrorheological fluid is kept at a low viscosity, so that vibration noise (handling noise) can be effectively reduced.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this. FIG. 1 is a cross-sectional view showing an internal structure of a microphone according to the present invention, and FIG. 2 is a cross-sectional view showing a damper used in the present invention as a shock mount.

  As shown in FIG. 1, this microphone is a handheld microphone. As a basic configuration, a microphone housing (microphone grip) 10 made of a metal material formed in a cylindrical shape and one end side of the microphone housing 10 are provided. And a microphone unit 30 that is elastically supported via a damper 20.

  An output connector 11 is provided on the other end side of the microphone housing 10. The output connector 11 may be a connector defined by EIAJRC-5236 “Latch lock type circular connector for audio equipment”. Further, a head case 12 made of, for example, a metal mesh is attached to one end side of the microphone housing 10 so as to cover the microphone unit 30.

  In this embodiment, the microphone unit 30 is a dynamic type (electrodynamic type), and although not shown, the unit case 31 has a diaphragm having a voice coil and a magnetic gap in which the voice coil is arranged to be able to vibrate. An acoustoelectric transducer including a magnetic circuit is accommodated.

  The microphone unit 30 may be a capacitor type. The directivity may be any one of omnidirectionality, unidirectionality, and bidirectionality.

  Referring to FIG. 2, the damper 20 includes an outer cylindrical portion 22 and an inner cylindrical portion 23, and includes a double cylindrical support ring 21 made of an elastic material such as rubber and having a sealed space inside. I have.

  As shown in FIG. 1, the outer cylindrical portion 22 is fitted along the inner peripheral surface on one end side of the microphone casing 10, and the rear end portion 31 a of the microphone unit 30 is formed on the upper end side of the inner cylindrical portion 23. Mated.

  That is, the microphone unit 30 is attached to the damper 20 by fitting the rear end portion 31 a to the upper end side of the inner cylindrical portion 23, and is elastically supported to the microphone casing 10 via the damper 20.

  A first electrode plate 25 is disposed on the outer cylindrical portion 22 side in the support ring 21, and a second electrode plate 26 facing the first electrode plate 25 is disposed on the inner cylindrical portion 23 side. Both the first electrode plate 25 and the second electrode plate 26 are cylindrical electrodes.

  In addition, an electrorheological fluid 27 whose viscosity can be freely changed by an applied voltage is enclosed in the support ring 21. The electrorheological fluid 27 is also called an ER fluid (Electro Rheological fluid), and is known as a reversible fluid that has a low viscosity when no voltage is applied, but whose viscosity increases instantaneously when a voltage is applied.

  The electrorheological fluid 27 can be broadly classified into a dispersion system in which dielectric fine particles are dispersed in insulating oil, and a uniform system in which molecules and domains are oriented by an electric field and exhibit anisotropy like liquid crystal. Any of them can be used in the invention.

  In this embodiment, the lower end side of the support ring 21 (on the side opposite to the support surface of the microphone unit 30) is closed by a bottom plate 24 formed integrally with the support ring 21, and the interior space of the support ring 21 is surrounded by the microphone unit. 30 back air chambers (back cavities) 20a.

  In order to change the viscosity of the electrorheological fluid 27, it is necessary to apply a voltage to the first electrode plate 25 and the second electrode plate 26. Therefore, the piezoelectric element 40 is integrally fixed in the microphone casing 10. For this fixing, for example, an adhesive may be used.

  The piezoelectric element 40 is deformed by a strong impact such as a drop impact applied to the microphone housing 10 to generate power. One output electrode 41 of the piezoelectric element 40 is electrically connected to the first electrode plate 25 via a lead wire 41a, and the other output electrode 42 is electrically connected to the second electrode plate 26 via a lead wire 42a. Is done.

  During normal use that does not receive a strong impact, almost no voltage is applied to the first electrode plate 25 and the second electrode plate 26 from the piezoelectric element 40, and the electrorheological fluid 27 is in a low viscosity state. Is elastically supported by the rubber elasticity of the support ring 21 and the low viscosity electrorheological fluid 27.

  As a result, vibration generated when the microphone housing 10 is rubbed with a finger or held, for example, is attenuated by the damper 20, so that vibration noise (handling noise) output from the microphone unit 30 is reduced. be able to.

  On the other hand, when a strong impact such as a drop impact is applied to the microphone housing 10, the piezoelectric element 40 generates power, and the voltage is applied to the first and second electrode plates 25 and 26. The viscosity increases instantaneously and the electrorheological fluid 27 becomes hard.

  Thereby, excessive displacement of the microphone unit 30 at the time of impact is suppressed, and collision with the head case 12 is prevented, so that no impact noise is generated, and damage to the microphone unit 30 can be prevented. it can.

Sectional drawing which shows the internal structure of the microphone by this invention. Sectional drawing which shows the damper used by this invention as a shock mount.

Explanation of symbols

10 Microphone housing 11 Output connector 12 Head case (windshield)
20 damper 20a back air chamber 21 support ring 22 outer cylindrical portion 23 inner cylindrical portion 24 bottom plate 25 first electrode plate 26 second electrode plate 27 electrorheological fluid (ER fluid)
30 Microphone unit 40 Piezoelectric element

Claims (3)

In a microphone formed by elastically supporting a microphone unit having an acoustoelectric converter through a buffering means at one end side of the microphone housing,
As the buffering means , a damper in which an electrorheological fluid is disposed between a pair of electrodes is used, and a piezoelectric element that generates electric power by an impact applied to the microphone casing is provided in the microphone casing. The piezoelectric element and each of the electrodes are electrically connected via lead wires ,
The damper includes an outer cylindrical portion that is fitted to an inner peripheral surface on one end side of the microphone casing and an inner cylindrical portion that is fitted to a rear end portion of the microphone unit, and has a space sealed inside. A double-cylindrical support ring made of an elastic material, wherein the electrodes are arranged on the outer cylindrical portion side and the inner cylindrical portion side in the support ring, respectively, and the electroviscous in the support ring A microphone in which a fluid is sealed . 2. The microphone according to claim 1, wherein the microphone unit is an electrodynamic microphone unit. 3. The microphone according to claim 2 , wherein a side opposite to the support ring of the support ring is closed by a bottom plate, and a back air chamber of the electrodynamic microphone unit is formed in the support ring.

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