JP2013120960A

JP2013120960A - Electroacoustic transducer

Info

Publication number: JP2013120960A
Application number: JP2011266470A
Authority: JP
Inventors: Yasuharu Onishi; 康晴大西; Atsushi Kuroda; 淳黒田; Shigeo Sato; 重夫佐藤; Motoyoshi Komoda; 元喜菰田
Original assignee: NEC Casio Mobile Communications Ltd
Current assignee: NEC Casio Mobile Communications Ltd
Priority date: 2011-12-06
Filing date: 2011-12-06
Publication date: 2013-06-17

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of an electrodynamic loudspeaker.SOLUTION: On the inside of a voice coil 8, a permanent magnet 2 is disposed. On the outside of the voice coil 8, a cylindrical member 3 of cylindrical outer shape having an internal cavity 4 filled with a magnetic fluid 5 is disposed. Consequently, the cost can be reduced when compared with a case where a relatively expensive permanent magnet is provided on the outside of the voice coil 8. Alternatively, a matter containing a magnetic fluid may be disposed on the inside of the voice coil, and a permanent magnet may be disposed on the outside of the voice coil. Alternatively, matters containing a magnetic fluid may be disposed on the inside and outside of the voice coil.

Description

この発明は電気音響変換装置に関する。 The present invention relates to an electroacoustic transducer.

従来の携帯電話等で用いられている電気音響変換装置には、磁気回路を有する動電型スピーカといわれるものがある（例えば、特許文献１参照）。特許文献１に記載の動電型スピーカでは、円筒形状の永久磁石の内側にヨークが設けられ、永久磁石およびヨークの上側に振動膜が設けられ、振動膜の下面中央部にボイスコイルの上部が取り付けられている。ボイスコイルは、永久磁石の内側においてヨークの周囲に上下動可能に配置されている。この動電型スピーカでは、ボイスコイルに音声電流が流れると、この音声電流に応じてボイスコイルが上下動し、これに伴い振動膜が振動し、まわりの空気を振動させて放音するようになっている。 Among electroacoustic transducers used in conventional mobile phones and the like, there is a so-called electrodynamic speaker having a magnetic circuit (see, for example, Patent Document 1). In the electrodynamic speaker described in Patent Document 1, a yoke is provided inside a cylindrical permanent magnet, a vibration film is provided above the permanent magnet and the yoke, and the upper part of the voice coil is located at the center of the lower surface of the vibration film. It is attached. The voice coil is arranged to be movable up and down around the yoke inside the permanent magnet. In this electrodynamic speaker, when a voice current flows through the voice coil, the voice coil moves up and down in accordance with the voice current, and accordingly, the vibrating membrane vibrates, and the surrounding air vibrates and emits sound. It has become.

特開２００４−１８７０３１号公報JP 2004-187031 A

しかしながら、上記従来の動電型スピーカでは、永久磁石およびヨークの材料として、希少金属であるジスプロシウムを含むネオジウム合金を用いる場合が多く、コスト高となってしまうという問題がある。 However, the conventional electrodynamic loudspeaker has a problem that the neodymium alloy containing dysprosium, which is a rare metal, is often used as the material for the permanent magnet and the yoke, resulting in a high cost.

そこで、この発明は、コストを低減することができる電気音響変換装置を提供することを目的とする。 Therefore, an object of the present invention is to provide an electroacoustic transducer that can reduce the cost.

この発明に係る電気音響変換装置は、ボイスコイルの内側および外側にそれぞれ磁石が設けられた電気音響変換装置において、前記２つの磁石のうち少なくとも１つは磁性流体を含むものによって形成されていることを特徴とするものである。 The electroacoustic transducer according to the present invention is an electroacoustic transducer in which magnets are respectively provided on the inner side and the outer side of the voice coil, and at least one of the two magnets is formed of a material containing a magnetic fluid. It is characterized by.

この発明によれば、コストを低減することができる。 According to the present invention, the cost can be reduced.

この発明の第１実施形態としての電気音響変換装置の要部の断面図。Sectional drawing of the principal part of the electroacoustic transducer as 1st Embodiment of this invention. この発明の第２実施形態としての電気音響変換装置の要部の断面図。Sectional drawing of the principal part of the electroacoustic transducer as 2nd Embodiment of this invention.

（第１実施形態）
図１はこの発明の第１実施形態としての電気音響変換装置の要部の断面図を示す。この電気音響変換装置は樹脂からなる円形状のベース板１を備えている。ベース板１の上面中央部には棒状の永久磁石２が接着剤（図示せず）を介して固着されている。ベース板１の上面外周部には樹脂からなる外形円筒形状の円筒部材３が接着剤（図示せず）を介して固着されている。円筒部材３の内部は空洞４となっており、この空洞４には磁性流体５が封入されている。磁性流体５としては、一例として、マンガン亜鉛フェライトを含むコロイド溶液が挙げられる。 (First embodiment)
FIG. 1 shows a cross-sectional view of a main part of an electroacoustic transducer as a first embodiment of the present invention. The electroacoustic transducer includes a circular base plate 1 made of resin. A rod-like permanent magnet 2 is fixed to the center of the upper surface of the base plate 1 via an adhesive (not shown). A cylindrical member 3 having an outer cylindrical shape made of resin is fixed to the outer peripheral portion of the upper surface of the base plate 1 with an adhesive (not shown). The inside of the cylindrical member 3 is a cavity 4 in which a magnetic fluid 5 is enclosed. An example of the magnetic fluid 5 is a colloidal solution containing manganese zinc ferrite.

円筒部材３の上面外周部にはポリエチレンテレフタレート等からなる平面円形状の振動膜６の下面外周部が接着剤７を介して固着されている。振動膜６は、ドーム状部６ａの外周部にドーム状のリング状部６ｂが設けられた構造となっている。振動膜６の下面中央部にはボイスコイル８の上部が接着剤（図示せず）を介して固着されている。ボイスコイル８は、円筒形状の円筒部材３の内側つまり円筒形状の磁性流体５の内側において永久磁石２の周囲に上下動可能に配置されている。 An outer peripheral portion of a lower surface of a planar circular vibration film 6 made of polyethylene terephthalate or the like is fixed to an outer peripheral portion of the upper surface of the cylindrical member 3 with an adhesive 7. The vibrating membrane 6 has a structure in which a dome-shaped ring-shaped portion 6b is provided on the outer periphery of the dome-shaped portion 6a. The upper part of the voice coil 8 is fixed to the center of the lower surface of the vibration film 6 via an adhesive (not shown). The voice coil 8 is disposed so as to be movable up and down around the permanent magnet 2 inside the cylindrical member 3, that is, inside the cylindrical magnetic fluid 5.

このように、この電気音響変換装置では、ボイスコイル８の外側に、円筒部材３の内部空洞４に磁性流体５が封入されたものからなる磁石を配置している。磁性流体５は、希少金属であるジスプロシウムを含むネオジウム合金からなる永久磁石と比較して安価であり、したがってボイスコイル８の外側に比較的高価な永久磁石を配置する場合と比較してコストを低減することができる。 As described above, in this electroacoustic transducer, the magnet made of the magnetic fluid 5 sealed in the internal cavity 4 of the cylindrical member 3 is disposed outside the voice coil 8. The ferrofluid 5 is less expensive than a permanent magnet made of a neodymium alloy containing dysprosium, which is a rare metal, and therefore has a lower cost than the case where a relatively expensive permanent magnet is disposed outside the voice coil 8. can do.

また、この電気音響変換装置では、振動膜６として、シート状ではなく、ドーム状部６ａの外周部にドーム状のリング状部６ｂが設けられた構造のものを用い、この振動膜６の下面外周部を円筒部材３の上面外周部に固着しているので、シート状の振動膜の下面外周部を円筒部材３の上面全体に固着する場合と比較して、振動膜６の振動可能面積を大きくすることができる。 In this electroacoustic transducer, the diaphragm 6 is not a sheet, but has a structure in which a dome-shaped ring-shaped portion 6b is provided on the outer periphery of the dome-shaped portion 6a. Since the outer peripheral portion is fixed to the outer peripheral portion of the upper surface of the cylindrical member 3, compared with the case where the lower peripheral portion of the lower surface of the sheet-like vibrating membrane is fixed to the entire upper surface of the cylindrical member 3, the vibration possible area of the vibrating membrane 6 is reduced. Can be bigger.

（第２実施形態）
図２はこの発明の第２実施形態としての電気音響変換装置の要部の断面図を示す。この電気音響変換装置において、図１に示す場合と大きく異なる点は、ボイスコイル１８の内側に磁性流体１４を配置し、ボイスコイル１８の外側に永久磁石１５を配置した点である。すなわち、この電気音響変換装置は樹脂からなる有底円筒形状のフレーム１１を備えている。 (Second Embodiment)
FIG. 2 shows a cross-sectional view of a main part of an electroacoustic transducer as a second embodiment of the present invention. In this electroacoustic transducer, the main difference from the case shown in FIG. 1 is that the magnetic fluid 14 is arranged inside the voice coil 18 and the permanent magnet 15 is arranged outside the voice coil 18. In other words, the electroacoustic transducer includes a bottomed cylindrical frame 11 made of resin.

フレーム１１の底部上面中央部には外形棒状の棒状部材１２が接着剤（図示せず）を介して固着されている。棒状部材１２の内部は空洞１３となっており、この空洞１３には磁性流体１４が封入されている。フレーム１１の底部上面外周部には円筒形状の永久磁石１５が接着剤（図示せず）を介して固着されている。 An outer rod-like rod-like member 12 is fixed to the center of the upper surface of the bottom portion of the frame 11 via an adhesive (not shown). The inside of the rod-shaped member 12 is a cavity 13 in which a magnetic fluid 14 is enclosed. A cylindrical permanent magnet 15 is fixed to the outer peripheral portion of the bottom upper surface of the frame 11 with an adhesive (not shown).

フレーム１１の周壁部上面全体には平面円形状でシート状の振動膜１６の下面外周部が接着剤１７を介して固着されている。振動膜１６の下面中央部にはボイスコイル１８の上部が接着剤（図示せず）を介して固着されている。ボイスコイル１８は、円筒形状の永久磁石１５の内側において棒状部材１２の内部空洞１４に封入された棒状の磁性流体１４の周囲に上下動可能に配置されている。 The outer peripheral portion of the lower surface of the planar diaphragm-like vibration film 16 is fixed to the entire upper surface of the peripheral wall portion of the frame 11 with an adhesive 17. The upper part of the voice coil 18 is fixed to the center of the lower surface of the vibration film 16 via an adhesive (not shown). The voice coil 18 is disposed so as to be movable up and down around the rod-shaped magnetic fluid 14 enclosed in the internal cavity 14 of the rod-shaped member 12 inside the cylindrical permanent magnet 15.

このように、この電気音響変換装置では、ボイスコイル１８の内側に、棒状部材１２の内部空洞１３に磁性流体１４が封入されたものからなる磁石を配置しているので、ボイスコイル１８の内側に比較的高価な永久磁石（ヨーク）を配置する場合と比較してコストを低減することができる。 Thus, in this electroacoustic transducer, since the magnet made of the magnetic fluid 14 sealed in the internal cavity 13 of the rod-shaped member 12 is arranged inside the voice coil 18, the inside of the voice coil 18 is arranged. Cost can be reduced compared with the case where a relatively expensive permanent magnet (yoke) is arranged.

ここで、図２に示す電気音響変換装置では、有底円筒形状のフレーム１１の内側に円筒形状の永久磁石１５を配置しているので、フレーム１１のサイズが比較的大きくなってしまう。これに対し、図１に示す電気音響変換装置では、ベース板１の上面外周部に円筒部材３を設け、この円筒部材３の内部空洞４に磁性流体５を封入しているので、ベース板１のサイズを比較的小さくすることができ、ひいては小型化することができる。なお、図１において、永久磁石２の代わりに、図２に示す、棒状部材１２の内部空洞１３に磁性流体１４か封入されたものを用いるようにしてもよい。 Here, in the electroacoustic transducer shown in FIG. 2, the cylindrical permanent magnet 15 is arranged inside the bottomed cylindrical frame 11, so that the size of the frame 11 becomes relatively large. In contrast, in the electroacoustic transducer shown in FIG. 1, the cylindrical member 3 is provided on the outer peripheral portion of the upper surface of the base plate 1, and the magnetic fluid 5 is sealed in the internal cavity 4 of the cylindrical member 3. Can be made relatively small, and consequently can be reduced in size. In FIG. 1, instead of the permanent magnet 2, a magnetic fluid 14 sealed in the internal cavity 13 of the rod-shaped member 12 shown in FIG. 2 may be used.

以下、この発明の諸態様を付記としてまとめて記載する。 Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

（付記１）
付記１の発明は、ボイスコイルの内側および外側にそれぞれ磁石が設けられた電気音響変換装置において、前記２つの磁石のうち少なくとも１つは磁性流体を含むものによって形成されていることを特徴とする電気音響変換装置である。 (Appendix 1)
The invention according to attachment 1 is characterized in that in the electroacoustic transducer in which the magnets are respectively provided on the inner side and the outer side of the voice coil, at least one of the two magnets is formed of one containing a magnetic fluid. An electroacoustic transducer.

（付記２）
付記２の発明は、付記１に記載の発明において、ベース板と、前記ベース板の上面中央部に設けられた前記磁石としての永久磁石と、前記ベース板の上面外周部に設けられ、外形が円筒形状で内部が空洞の円筒部材と、前記円筒部材の空洞内に設けられた前記磁性流体と、下面外周部が前記円筒部材の上面に固着された振動膜と、前記振動膜の下面中央部に設けられ、前記円筒部材の内側において前記永久磁石の周囲に上下動可能に配置された前記ボイスコイルとを備えていることを特徴とする電気音響変換装置である。 (Appendix 2)
The invention according to appendix 2 is the invention according to appendix 1, wherein the base plate, the permanent magnet as the magnet provided at the center of the upper surface of the base plate, and the outer periphery of the upper surface of the base plate are provided. A cylindrical member having a cylindrical shape and a hollow inside, the magnetic fluid provided in the cavity of the cylindrical member, a vibrating membrane having a lower surface outer peripheral portion fixed to the upper surface of the cylindrical member, and a lower surface central portion of the vibrating membrane And the voice coil arranged to be movable up and down around the permanent magnet inside the cylindrical member.

（付記３）
付記３の発明は、付記２に記載の発明において、前記振動膜は、ドーム状部の外周部にドーム状のリング状部が設けられた構造であり、前記振動膜の下面外周部は前記円筒部材の上面外周部に固着されていることを特徴とする電気音響変換装置である。 (Appendix 3)
The invention according to appendix 3 is the invention according to appendix 2, wherein the vibrating membrane has a structure in which a dome-shaped ring-shaped portion is provided on an outer peripheral portion of the dome-shaped portion, and an outer peripheral portion on the lower surface of the vibrating membrane is the cylindrical It is an electroacoustic transducer characterized by being fixed to the outer peripheral part of the upper surface of a member.

（付記４）
付記４の発明は、付記１に記載の発明において、ベース板と、前記ベース板の上面中央部に設けられ、外形が棒状で内部が空洞の棒状部材と、前記棒状部材の空洞内に設けられた前記磁性流体と、前記ベース板の上面外周部に設けられ、外形が円筒形状で内部が空洞の円筒部材と、前記円筒部材の空洞内に設けられた前記磁性流体と、下面外周部が前記円筒部材の上面に固着された振動膜と、前記振動膜の下面中央部に設けられ、前記円筒部材の内側において前記棒状部材の周囲に上下動可能に配置された前記ボイスコイルとを備えていることを特徴とする電気音響変換装置である。 (Appendix 4)
The invention of supplementary note 4 is the invention according to supplementary note 1, wherein the base plate is provided in the center of the upper surface of the base plate, the rod-shaped member having an outer shape in a rod shape and having a hollow inside, and the cavity in the rod-shaped member. The magnetic fluid, a cylindrical member having a cylindrical outer shape and having a hollow inside, the magnetic fluid provided in the cavity of the cylindrical member, and a lower surface outer peripheral portion are provided on the outer peripheral portion of the upper surface of the base plate. The vibration film fixed to the upper surface of the cylindrical member, and the voice coil provided at the center of the lower surface of the vibration film and arranged to move up and down around the rod-shaped member inside the cylindrical member. This is an electroacoustic transducer characterized by the above.

（付記５）
付記５の発明は、付記１に記載の発明において、有底円筒形状のフレームと、前記フレームの底部上面中央部に設けられ、外形が棒状で内部が空洞の棒状部材と、前記棒状部材の空洞内に設けられた前記磁性流体と、前記フレームの底部上面外周部に設けられた円筒形状の前記磁石としての永久磁石と、下面外周部が前記フレームの周壁部上面に固着された振動膜と、前記振動膜の下面中央部に設けられ、前記永久磁石の内側において前記棒状部材の周囲に上下動可能に配置された前記ボイスコイルとを備えていることを特徴とする電気音響変換装置である。 (Appendix 5)
The invention according to appendix 5 is the invention according to appendix 1, wherein a bottomed cylindrical frame, a bar-shaped member having an outer shape of a rod and having a hollow inside, and a cavity of the rod-shaped member, provided at the center of the upper surface of the bottom of the frame The magnetic fluid provided inside, a permanent magnet as the cylindrical magnet provided on the outer periphery of the upper surface of the bottom of the frame, and a vibrating membrane having a lower surface outer peripheral part fixed to the upper surface of the peripheral wall of the frame; An electroacoustic transducer comprising: the voice coil provided at a central portion of the lower surface of the vibrating membrane and arranged to be movable up and down around the rod-shaped member inside the permanent magnet.

１ベース板
２永久磁石
３円筒部材
４空洞
５磁性流体
６振動膜
７接着剤
８ボイスコイル DESCRIPTION OF SYMBOLS 1 Base plate 2 Permanent magnet 3 Cylindrical member 4 Cavity 5 Magnetic fluid 6 Vibration film 7 Adhesive 8 Voice coil

Claims

An electroacoustic transducer in which a magnet is provided on each of an inner side and an outer side of a voice coil, wherein at least one of the two magnets is formed of a magnetic fluid.

The invention according to claim 1, wherein the base plate, the permanent magnet as the magnet provided at the center of the upper surface of the base plate, and the outer periphery of the upper surface of the base plate are provided with a cylindrical outer shape and an inner portion. A hollow cylindrical member, the magnetic fluid provided in the hollow of the cylindrical member, a vibrating membrane having a lower surface outer peripheral portion fixed to the upper surface of the cylindrical member, and a lower surface central portion of the vibrating membrane, An electroacoustic transducer comprising: the voice coil disposed inside the cylindrical member so as to be movable up and down around the permanent magnet.

The invention according to claim 2, wherein the vibration film has a structure in which a dome-shaped ring-shaped part is provided on an outer periphery of the dome-shaped part, and a lower surface outer peripheral part of the vibration film is an upper surface outer peripheral part of the cylindrical member An electroacoustic transducer characterized in that the electroacoustic transducer is fixed to the surface.

The invention according to claim 1, wherein the base plate, a bar-shaped member having an outer shape of a rod shape and having a hollow inside, and the magnetic fluid provided in the cavity of the rod-shaped member, are provided at the center of the upper surface of the base plate. A cylindrical member having a cylindrical outer shape and having a hollow inside; the magnetic fluid provided in the cavity of the cylindrical member; and a lower peripheral portion on the upper surface of the cylindrical member. It is provided with a fixed vibration film, and the voice coil which is provided at the center of the lower surface of the vibration film and which can be moved up and down around the rod-shaped member inside the cylindrical member. Electroacoustic transducer.

In the invention according to claim 1, a bottomed cylindrical frame, a rod-shaped member having an outer shape of a rod and having a hollow inside, and provided in a cavity of the rod-shaped member are provided at the center of the upper surface of the bottom of the frame. The magnetic fluid, a permanent magnet as the cylindrical magnet provided on the outer periphery of the upper surface of the bottom of the frame, a vibration film having a lower surface outer peripheral part fixed to the upper surface of the peripheral wall of the frame, and a lower surface of the vibration film An electroacoustic transducer comprising: the voice coil provided at a central portion and arranged to move up and down around the rod-shaped member inside the permanent magnet.