JP2917578B2 - Speaker - Google Patents
SpeakerInfo
- Publication number
- JP2917578B2 JP2917578B2 JP13911691A JP13911691A JP2917578B2 JP 2917578 B2 JP2917578 B2 JP 2917578B2 JP 13911691 A JP13911691 A JP 13911691A JP 13911691 A JP13911691 A JP 13911691A JP 2917578 B2 JP2917578 B2 JP 2917578B2
- Authority
- JP
- Japan
- Prior art keywords
- speaker
- magnetic
- peripheral surface
- gap
- voice coil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
- H04R9/025—Magnetic circuit
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2209/00—Details of transducers of the moving-coil, moving-strip, or moving-wire type covered by H04R9/00 but not provided for in any of its subgroups
- H04R2209/022—Aspects regarding the stray flux internal or external to the magnetic circuit, e.g. shielding, shape of magnetic circuit, flux compensation coils
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は動電形スピーカに関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic speaker.
【０００２】[0002]
【従来の技術】近年、デジタル信号処理技術が飛躍的に
進歩したため、スピーカに供給される電気信号は大幅に
その質が向上し、これに対応して高音質再生の可能なス
ピーカが求められてきている。一方、音と映像の融合化
に伴い、スピーカはブラウン管色ズレ等の影響を防止す
るため、磁気回路に防磁対策を施すことが一般的となっ
てきている。高音質再生のためには、スピーカ自体の駆
動力歪が極めて少ないことが望ましい。現在、スピーカ
自体の駆動力歪を減少させる対策として、センターポー
ルと磁気ギャップをなすプレートの厚みに対してボイス
コイルの巻幅を大きくとるロングボイスコイル形、もし
くはこれとは逆にボイスコイルの巻幅を小さくとるショ
ートボイスコイル形が用いられる。また、高音再生時に
駆動力歪の原因となる渦電流の影響を取り除くために、
磁気ギャップ内にショートリングが設けられている。一
方、防磁対策は、磁気ギャップと磁路を形成しない防磁
専用の磁石で、磁気回路の外周部を覆うヨークカバーを
磁気的に同極とすることでなされる。2. Description of the Related Art In recent years, the digital signal processing technology has been dramatically advanced, and the quality of electric signals supplied to a speaker has been greatly improved. Accordingly, a speaker capable of reproducing high-quality sound has been demanded. ing. On the other hand, with the integration of sound and video, it has become common for speakers to take measures against magnetic shielding in magnetic circuits in order to prevent the effects of CRT color shift and the like. For high-quality sound reproduction, it is desirable that the driving force distortion of the speaker itself is extremely small. At present, as a measure to reduce the driving force distortion of the speaker itself, a long voice coil type in which the winding width of the voice coil is made larger than the thickness of the plate forming the magnetic gap with the center pole, or conversely, the voice coil winding A short voice coil type having a small width is used. Also, in order to remove the effects of eddy currents that cause driving force distortion during high-frequency sound reproduction,
A short ring is provided in the magnetic gap. On the other hand, the countermeasure against the magnetic field is made by making the yoke cover that covers the outer peripheral portion of the magnetic circuit magnetically the same with a magnet dedicated to the magnetic field that does not form a magnetic gap and a magnetic path.
【０００３】以下に従来のスピーカについて説明する。
（図４）に従来のスピーカの構造断面図を示す。図中の
１はボトムプレート、２はセンターポール、３はセンタ
ーポール２と磁気ギャップをなすトッププレート、４は
磁石、５はショートリング、６は防磁用磁石、７はヨー
クカバーである。[0003] A conventional speaker will be described below.
FIG. 4 shows a structural sectional view of a conventional speaker. In the figure, 1 is a bottom plate, 2 is a center pole, 3 is a top plate forming a magnetic gap with the center pole 2, 4 is a magnet, 5 is a short ring, 6 is a magnet for magnetic shielding, and 7 is a yoke cover.
【０００４】従来のスピーカでは、防磁形とするために
防磁専用の磁石６が、磁石４とは逆方向に着磁され、ボ
トムプレート１の下面に設けられ、磁石６とトッププレ
ート３に接するヨークカバー７を設けている。この結
果、トッププレート３とヨークカバー７は磁気的に同極
となるため、スピーカ外部への磁気漏洩は非常に少なく
なる。また、ショートリング５が磁気ギャップ内の磁路
中に存在する構造を取っている。In the conventional loudspeaker, a magnet 6 dedicated to magnetic shielding is magnetized in a direction opposite to that of the magnet 4 so as to be magnetically shielded, is provided on the lower surface of the bottom plate 1, and is in contact with the magnet 6 and the top plate 3. A cover 7 is provided. As a result, the top plate 3 and the yoke cover 7 have the same magnetic polarity, so that magnetic leakage to the outside of the speaker is extremely reduced. In addition, the structure is such that the short ring 5 exists in the magnetic path in the magnetic gap.
【０００５】[0005]
【発明が解決しようとする課題】このような従来の技術
では、大入力時の低音域での大振幅に伴い増大する駆動
力歪を低減するために、大振幅時にもボイスコイルが磁
気ギャップ内からはみ出さない構造として、ボイスコイ
ルの巻幅がトッププレート３の厚みよりも大きなロング
ボイスコイル形、あるいはこれとは逆に、トッププレー
ト３の厚みよりもボイスコイルの巻幅が小さいショート
ボイスコイル形が用いられてきた。In such a conventional technique, in order to reduce a driving force distortion which increases with a large amplitude in a low frequency range at the time of a large input, the voice coil remains in the magnetic gap even at a large amplitude. As a structure that does not protrude, a long voice coil type in which the winding width of the voice coil is larger than the thickness of the top plate 3 or, conversely, a short voice coil in which the winding width of the voice coil is smaller than the thickness of the top plate 3 Shapes have been used.
【０００６】すなわち、磁気ギャップ内に存在するボイ
スコイルの体積が、所望のボイスコイルの振幅範囲で一
定となり、駆動力も振幅の大小に関わらず一定値となる
ように設計される。しかしながら、ロングボイスコイル
形の場合、所望の振幅範囲で一定の駆動力を得るために
は、ボイスコイルの巻幅を非常に長く取らなければなら
ず、その結果、ボイスコイルの重量が大きくなる。しか
も、磁気ギャップの外部に存在するボイスコイル部分は
駆動力に全く寄与せず、電気エネルギーを有効に機械エ
ネルギーに変換することができず、スピーカとしての能
率は低下する。That is, the volume of the voice coil present in the magnetic gap is designed to be constant within a desired amplitude range of the voice coil, and the driving force is designed to be constant regardless of the magnitude of the amplitude. However, in the case of the long voice coil type, in order to obtain a constant driving force in a desired amplitude range, the winding width of the voice coil must be made very long, and as a result, the weight of the voice coil increases. In addition, the voice coil portion existing outside the magnetic gap does not contribute to the driving force at all, cannot effectively convert electric energy into mechanical energy, and the efficiency as a speaker decreases.
【０００７】一方、ショートボイスコイル形の場合、所
望の振幅範囲で一定の駆動力を得るためには、センター
ポール２と磁気ギャップをなすトッププレート３を非常
に厚く取らなければならない。この結果、磁気ギャップ
内でのボイスコイルの占める体積は非常に小さくなり、
変換効率の観点からみると磁気エネルギーを有効に使う
ことができない。しかも、磁気ギャップ内に所望の磁束
密度を得るには非常に大きな磁石が必要となり、磁気回
路が巨大なものとなり、形状や重量、コストの点からも
実用上問題となる。On the other hand, in the case of the short voice coil type, in order to obtain a constant driving force in a desired amplitude range, the center pole 2 and the top plate 3 forming a magnetic gap must be made very thick. As a result, the volume occupied by the voice coil in the magnetic gap becomes very small,
From the viewpoint of conversion efficiency, magnetic energy cannot be used effectively. Moreover, in order to obtain a desired magnetic flux density in the magnetic gap, a very large magnet is required, and the magnetic circuit becomes huge, which poses practical problems in terms of shape, weight, and cost.
【０００８】次に中高音域では、ボイスコイルに発生す
る交流磁界により、渦電流に起因してボイスコイルに流
れる電流が歪み、この結果として駆動力に歪が発生す
る。この電流歪を改善するために、電気伝導率の高い材
料、例えば銅がショートリング５として磁気ギャップ内
に設けられている。しかしながら、このショートリング
５はセンターポール２とトッププレート３との磁気ギャ
ップ内に存在するため、センターポール２はショートリ
ング５の厚み分だけ小さく設計されることになり、ショ
ートリング５は非磁性体であるため磁気ギャップの磁路
は広くなって磁気ギャップ内に十分な磁束密度が得られ
ず、スピーカの能率を低下させる原因となっていた。Next, in the mid-high range, the AC magnetic field generated in the voice coil causes the current flowing through the voice coil to be distorted due to the eddy current, and as a result, the driving force is distorted. In order to improve the current distortion, a material having high electric conductivity, for example, copper, is provided as a short ring 5 in the magnetic gap. However, since the short ring 5 exists in the magnetic gap between the center pole 2 and the top plate 3, the center pole 2 is designed to be smaller by the thickness of the short ring 5, and the short ring 5 is made of a non-magnetic material. Therefore, the magnetic path of the magnetic gap is widened, and a sufficient magnetic flux density cannot be obtained in the magnetic gap, causing a reduction in the efficiency of the speaker.
【０００９】防磁対策は、防磁用磁石６を用いて、磁気
回路の外周部を覆うヨークカバー７とトッププレート３
を磁気的に同極とすることで、スピーカ外部へ磁気漏洩
を僅かなものとしている。しかしながら、このような構
造では防磁用磁石６とヨークカバー７の存在のため、ス
ピーカの体積及び重量が大きくなり実用上好ましくな
い。To prevent the magnetic field, a yoke cover 7 for covering the outer peripheral portion of the magnetic circuit and a top plate
Are magnetically of the same polarity, so that magnetic leakage to the outside of the speaker is reduced. However, in such a structure, the presence and absence of the magnet 6 and the yoke cover 7 increase the volume and weight of the speaker, which is not preferable in practical use.
【００１０】本発明では大振幅時においても駆動力が一
定で、ショートリング５の存在が磁気ギャップ内の磁束
密度を低下させることなく、極めて駆動力歪が少なく、
しかも高能率な小型軽量スピーカを提供することを目的
とする。In the present invention, the driving force is constant even at the time of a large amplitude, and the presence of the short ring 5 does not reduce the magnetic flux density in the magnetic gap.
Moreover, it is an object of the present invention to provide a highly efficient small and lightweight speaker.
【００１１】[0011]
【課題を解決するための手段】本発明は上記目的を達成
するために、円周方向に着磁された２つの環状磁石を上
下方向に環状磁石の厚み分の間隙を持たせて、センター
ポールとヨークとの間に設け、環状磁石の外周面とヨー
クの内周面、あるいは環状磁石の内周面とセンターポー
ルの外周面とで磁気ギャップを構成し、ボイスコイルの
巻幅を、２つの環状磁石の間隙と、環状磁石１つ分の厚
みとの和とし、２つの環状磁石の間隙にショートリング
を設ける。SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a center pole having two circumferentially magnetized annular magnets with a gap in the vertical direction corresponding to the thickness of the annular magnet. And a yoke, a magnetic gap is formed by the outer peripheral surface of the annular magnet and the inner peripheral surface of the yoke, or the inner peripheral surface of the annular magnet and the outer peripheral surface of the center pole. A short ring is provided in the gap between the two ring magnets, which is the sum of the gap between the ring magnets and the thickness of one ring magnet.
【００１２】[0012]
【作用】本発明は上記した構成により、防磁専用の磁石
を必要としない磁気漏洩の極めて少ないスピーカを提供
し、大振幅時においても一定の駆動力をもち、スピーカ
への高周波入力時に渦電流による駆動力歪を極めて低く
抑えることができ、しかもショートリングを備えながら
も磁気ギャップ内に十分な磁束密度が得られる。According to the present invention, there is provided a speaker having a very small magnetic leakage which does not require a magnet dedicated to magnetic shielding, having a constant driving force even at a large amplitude, and an eddy current generated at a high frequency input to the speaker. Driving force distortion can be kept extremely low, and a sufficient magnetic flux density can be obtained in the magnetic gap while having a short ring.
【００１３】[0013]
【実施例】本発明の第１の実施例の構造断面図とボイス
コイル部の詳細図をそれぞれ（図１）と（図２）に示
す。ここで、（図１（ａ））は２つの環状磁石の内周面
とセンターポールの外周面とで磁気ギャップを構成する
場合、（図１（ｂ））は２つの環状磁石の外周面とヨー
クの内周面とで磁気ギャップを構成する場合である。図
中の８はプレート、９はセンターポール、１０はヨー
ク、１１と１２は円周方向に着磁された環状磁石、１３
はボイスコイルである。FIG. 1 is a sectional view showing a structure of a first embodiment of the present invention, and FIG. Here, (FIG. 1 (a)) shows a case where a magnetic gap is formed by the inner peripheral surface of the two annular magnets and the outer peripheral surface of the center pole, and (FIG. 1 (b)) shows the outer peripheral surface of the two annular magnets. This is a case where a magnetic gap is formed with the inner peripheral surface of the yoke. In the figure, 8 is a plate, 9 is a center pole, 10 is a yoke, 11 and 12 are annular magnets magnetized in the circumferential direction, 13
Is a voice coil.
【００１４】上記構成において動作を説明する。（図
２）のＴmagは環状磁石１１，１２の厚み、Ｔdisは環状
磁石１１と１２との間隙、Ｔvcはボイスコイル１３の巻
幅である。ボイスコイル１１が、上下振幅の中立点であ
る（図２（ａ））の状態から上方へ移動する場合、（図
２（ｂ））に示すように上方への移動距離がＴdis＋Ｔ
mag／２までは、磁気ギャップ内に存在するボイスコイ
ル１１の体積が一定であるために駆動力が一定となる。
また、（図２（ａ））の状態から下方へ移動する場合、
（図２（ｃ））に示すように下方への移動距離がＴdis
＋Ｔmag／２までは、同様に駆動力は一定となる。ま
た、環状磁石１１と１２は円周方向に着磁されているた
め、プレート８、ヨーク１０は磁気的に同極となり、ス
ピーカ外部への磁気漏洩が極めて少なくなる。The operation of the above configuration will be described. T mag of (2) is a gap between the thickness of the ring magnet 11, 12, T dis is annular magnet 11 and 12, T vc is the winding width of the voice coil 13. When the voice coil 11 moves upward from the state of the neutral point of the vertical amplitude (FIG. 2A), the upward moving distance is T dis + T as shown in FIG. 2B.
Up to mag / 2, the driving force is constant because the volume of the voice coil 11 existing in the magnetic gap is constant.
Also, when moving downward from the state of FIG. 2 (a),
As shown in FIG. 2C, the downward moving distance is T dis
The driving force is similarly constant up to + T mag / 2. Further, since the annular magnets 11 and 12 are magnetized in the circumferential direction, the plate 8 and the yoke 10 have the same magnetic polarity, and magnetic leakage to the outside of the speaker is extremely reduced.
【００１５】次に、第２の実施例の構造断面図を（図
３）に示す。（図３（ａ））は２つの環状磁石の内周面
とセンターポールの外周面とで磁気ギャップを構成する
場合であり、（図３（ｂ））は２つの環状磁石の外周面
とヨークの内周面とで磁気ギャップを構成する場合であ
る。第１の実施例と大きく異なるのは、環状磁石１１と
１２との間隙にショートリング１４を設けたことであ
り、その他の構成は同一である。なお、このショートリ
ング１４は従来例と同様、電気伝導率の高い材料、例え
ば銅にて構成している。環状磁石１１と１２との間隙に
ショートリング１４を設けるため、磁気ギャップの磁路
を従来のようにショートリングの分だけ広げることなく
磁気回路を構成でき、スピーカの駆動時に生じる渦電流
の大部分はショートリング１４を流れる。Next, FIG. 3 shows a sectional view of the structure of the second embodiment. FIG. 3A shows a case where a magnetic gap is formed by the inner peripheral surface of the two annular magnets and the outer peripheral surface of the center pole, and FIG. 3B shows the outer peripheral surface of the two annular magnets and the yoke. Is a case where a magnetic gap is formed with the inner peripheral surface of the magnetic head. The major difference from the first embodiment is that a short ring 14 is provided in the gap between the annular magnets 11 and 12, and the other configuration is the same. The short ring 14 is made of a material having a high electric conductivity, for example, copper, as in the conventional example. Since the short ring 14 is provided in the gap between the annular magnets 11 and 12, a magnetic circuit can be formed without expanding the magnetic path of the magnetic gap by the length of the short ring as in the related art, and most of the eddy current generated when the speaker is driven. Flows through the short ring 14.
【００１６】[0016]
【発明の効果】以上のように、本発明は大振幅時におい
ても一定の駆動力をもち、磁路中にショートリングの存
在しない、しかも防磁専用の磁石を必要としないスピー
カを提供するものであり、これまでの駆動力を一定にす
るための手段であるロングボイスコイル形、及びショー
トボイスコイル形では電気エネルギー及び磁気エネルギ
ーを有効利用できなかった問題をはじめ、渦電流を逃が
すためのショートリングが磁路中に存在したため、磁気
ギャップの磁路が広くなって磁気ギャップ内に十分な磁
束密度が得られなかった問題や、防磁専用の磁石の存在
ために小型軽量化できなかった問題を解決できるため、
従来のスピーカでは得られなかった駆動力歪の極めて少
ない、しかも高能率の小型軽量スピーカを実現できるも
のである。As described above, the present invention provides a speaker which has a constant driving force even at the time of large amplitude, has no short ring in the magnetic path, and does not require a magnet dedicated to magnetic shielding. There is a short ring for releasing eddy currents, including the problem that electric and magnetic energy could not be used effectively with the long voice coil type and the short voice coil type, which have been used to keep the driving force constant. In the magnetic path, the magnetic path of the magnetic gap was widened, and sufficient magnetic flux density could not be obtained in the magnetic gap. Because you can
It is possible to realize a highly efficient small and lightweight speaker with very little driving force distortion that cannot be obtained with a conventional speaker.
【図１】本発明の第１の実施例のスピーカの構造断面図
である。FIG. 1 is a structural sectional view of a speaker according to a first embodiment of the present invention.
【図２】本発明の第１の実施例のスピーカのボイスコイ
ル部の詳細図である。FIG. 2 is a detailed view of a voice coil unit of the speaker according to the first embodiment of the present invention.
【図３】本発明の第２の実施例のスピーカの構造断面図
である。FIG. 3 is a structural sectional view of a speaker according to a second embodiment of the present invention.
【図４】従来例のスピーカの構造断面図である。FIG. 4 is a structural sectional view of a conventional speaker.
８ プレート ９ センターポール １０ ヨーク １１，１２ 環状磁石 １３ ボイスコイル １４ ショートリング 8 Plate 9 Center pole 10 Yoke 11, 12 Ring magnet 13 Voice coil 14 Short ring
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−99700（ＪＰ，Ａ) 特開 昭54−91313（ＪＰ，Ａ) 特開 平１−98400（ＪＰ，Ａ) 実開 昭63−140793（ＪＰ，Ｕ) 実開 昭61−128896（ＪＰ，Ｕ) 実開 昭57−43688（ＪＰ，Ｕ) 実開 昭56−172092（ＪＰ，Ｕ) 実開 昭62−121899（ＪＰ，Ｕ) 実開 昭60−160697（ＪＰ，Ｕ) 実開 昭59−161610（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.6，ＤＢ名) H04R 9/02 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-99700 (JP, A) JP-A-54-91313 (JP, A) JP-A-1-98400 (JP, A) 140793 (JP, U) Fully open 1987-128896 (JP, U) Fully open 1979-43688 (JP, U) Fully open, 56-172092 (JP, U) Fully open, 62-121899 (JP, U) Japanese Utility Model Application Showa 60-160697 (JP, U) Japanese Utility Model Application Showa 59-161610 (JP, U) (58) Fields investigated (Int. Cl. 6 , DB name) H04R 9/02
Claims (7)
クを備えて一体化されたプレートから構成され、前記セ
ンターポールの外周面と前記ヨークの内周面との間に、
円周方向に着磁された環状磁石を上下方向に複数個設け
た構造を有することを特徴とするスピーカ。1. An integrated plate comprising a center pole at a center portion and a yoke at an outer peripheral portion, wherein a plate is provided between an outer peripheral surface of the center pole and an inner peripheral surface of the yoke.
A speaker having a structure in which a plurality of circumferentially magnetized annular magnets are provided in a vertical direction.
し、前記環状磁石の外周面がヨークの内周面との間で磁
気ギャップを構成する構造を有することを特徴とする請
求項１記載のスピーカ。2. The structure according to claim 1, wherein the inner peripheral surface of the annular magnet is in contact with the center pole, and the outer peripheral surface of the annular magnet forms a magnetic gap with the inner peripheral surface of the yoke. Speaker.
環状磁石の内周面がセンターポールの外周面との間で磁
気ギャップを構成する構造を有することを特徴とする請
求項１記載のスピーカ。3. The structure according to claim 1, wherein an outer peripheral surface of the annular magnet is in contact with the yoke, and an inner peripheral surface of the annular magnet forms a magnetic gap with an outer peripheral surface of the center pole. Speaker.
みと等しい構造を有することを特徴とする請求項１記載
のスピーカ。4. The speaker according to claim 1, wherein a gap between the annular magnets has a structure equal to a thickness of the magnets.
を特徴とする請求項４記載のスピーカ。5. The loudspeaker according to claim 4, wherein the loudspeaker has a structure having two annular magnets.
構造を有することを特徴とする請求項４記載のスピー
カ。6. The speaker according to claim 4, wherein the speaker has a structure in which a highly conductive material is provided in a gap between the annular magnets.
と環状磁石の厚みの和に等しい構造を有することを特徴
とする請求項４記載のスピーカ。7. The speaker according to claim 4, wherein the voice coil has a winding width equal to the sum of the gap between the annular magnets and the thickness of the annular magnet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13911691A JP2917578B2 (en) | 1991-06-11 | 1991-06-11 | Speaker |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13911691A JP2917578B2 (en) | 1991-06-11 | 1991-06-11 | Speaker |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04363999A JPH04363999A (en) | 1992-12-16 |
| JP2917578B2 true JP2917578B2 (en) | 1999-07-12 |
Family
ID=15237871
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13911691A Expired - Fee Related JP2917578B2 (en) | 1991-06-11 | 1991-06-11 | Speaker |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2917578B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4594562B2 (en) * | 2001-08-21 | 2010-12-08 | アルパイン株式会社 | Magnetic circuit of speaker |
| JP2006060333A (en) * | 2004-08-17 | 2006-03-02 | Pioneer Electronic Corp | Magnetic circuit for speaker, and speaker system |
| JP4463048B2 (en) | 2004-08-27 | 2010-05-12 | アルパイン株式会社 | speaker |
| JP2007306214A (en) * | 2006-05-10 | 2007-11-22 | Fujitsu Ten Ltd | Speaker magnetic circuit |
| US8577074B2 (en) * | 2011-02-14 | 2013-11-05 | Robert Bosch Gmbh | Vortex cooling of voice coils |
| US8781150B2 (en) * | 2011-02-14 | 2014-07-15 | Robert Bosch Gmbh | Multiple magnetic air gap motor |
-
1991
- 1991-06-11 JP JP13911691A patent/JP2917578B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04363999A (en) | 1992-12-16 |
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