JP3882766B2 - Manufacturing method of speaker diaphragm - Google Patents

Description

なお、図１０中のＡ点はカバ（無垢材）であり、以下、Ｂ点；シナ（無垢材）、Ｃ点；ブナ（無垢材）、Ｄ点；オーク（無垢材）、Ｅ点；チェリー（無垢材）、Ｆ点；スプルース（無垢材）、Ｇ点；シナ合板（共芯）、Ｈ点；ラワン合板、Ｉ点；ＭＦＤ、Ｊ点；パーティクルボードである。
【００３１】
次に、上記スピーカ用振動板３０の製造方法を図１の（ａ）から（ｊ）までのフロー図及び図２、図３の対応する（ａ）から（ｊ）までの模式図に従って説明する。
【００３２】
先ず、請求項２に係る第１の実施の形態（Ｂ）のスピーカ用振動板３０の製造工程は、図１に示されるように予め素材準備段階で（ｐ）木製シートの作成の後の（ａ）〜（ｊ）までの１１工程で構成され、（ａ）貼り合わせシート作成、（ｂ）Ｖ字状切り込みの形成、（ｃ）潤滑剤含浸、（ｄ１）略ラッパ形状に掛止、（ｄ２）仮成形の１次プレス、（ｅ）乾燥、（ｆ）熱硬化性樹脂含浸、（ｇ）半乾燥、（ｈ）２次プレス、（ｉ）防湿剤塗布、（ｊ）中心孔・外形抜きの順に行われてスピーカ用振動板の完成となる。
【００３３】
上記各工程の詳細内容を以下順に説明する。
工程（ａ）・・・０．ｌｍｍ〜０．９ｍｍ厚（好ましくは０．３ｍｍ程度）の木製シート１０の一面側に、接着剤により略０．０２〜０．３０ｍｍ厚の不織布又は和紙１３を貼り合わせて貼り合わせシート１５を作成する。ここにいう不織布はカーボン材その他の合成樹脂からなる周知材料であり、貼り合わせた一面側が完成した振動板３０の背面側となる。上記木製シート１０の厚さは成形性と音響特性及びダイナミック・スピーカの口径を考慮した上でのスピーカ用振動板として適正な厚さである。
工程（ｂ）・・・貼り合わせシート１５に対して、中心部に頂点が至る略Ｖ字状の切り込み１１とその頂点近傍に小穴１２を設ける。前記切り込み１１は、貼り合わせシート１５の木目方向（矢印ｆ）に概ね沿って設ける。なお、上記小穴１２は略ラッパ形状に成形する際の中心部の割れを防止するためのものであり、直径数ミリの円形、楕円形、六角形等であって形状に制限はない。
工程（ｃ）・・・Ｖ字切り込みした前記貼り合わせシート１５が軟化するように、貼り合わせシート１５の中に浸透して水分を与え且つ水分を保持する作用のある潤滑剤１６の液中に５〜６０分浸して十分に含浸させる。
【００３４】
これは後の１次プレス加熱成形を実施する時に割れを未然に防ぎ、歩留まり良く仮成形するためである。本発明者の研究によれば前記潤滑剤１６としては、単なる水若しくはアルカリ水溶液ではなく、糖類を溶解させた水溶液が適する。
工程（ｄ１）・・・貼り合わせシート１５の切り込み１１の両縁部１１ａ、１１ｂ同士を重ね合わせて図６に示されるような略ラッパ形状になるように成形外領域（余白部分）を掛止具２６で掛止保持する。前記掛止具２６としてはホッチキス（商標名）やクリップ等の紙綴じ器が利用でき、前記両縁部１１ａ、１１ｂの延長上の余白部分を止めれば簡単に掛止保持することができ、１次プレス加熱成形の作業性、加工精度が良好となる。
工程（ｄ２）・・・ヒータ３３を各々備えた上型３１と下型３２の金型構成のプレス装置Ｐ１によって、前記潤滑剤１６を含浸させ掛止具２６で略ラッパ形状に保持させた貼り合わせシート１５を１次プレス加熱成形（仮成形）する。ここで１次プレス加熱成形の設定条件は、プレス圧力が略１〜１０Ｋｇ、金型温度は上型３１が略８０〜１５０℃、下型３２が略１００〜２００℃、プレス時間が略２〜６０秒である。なお、上記噛み合わせ掛止機構１４によってプレス装置Ｐ１にセッティングする前から略ラッパ状に形状が保持されているため、セッティングの作業性が向上し、且つ１次プレス加熱成形（仮成形）の成形性の向上（しわや割れが少ない）が実現している。
工程（ｅ）・・・乾燥炉（５０〜６０℃）に略１０〜３０分間入れて完全乾燥を行なう。
工程（ｆ）・・・乾燥後の貼り合わせシート１５を熱硬化性樹脂１７液中に略３０分〜１８０分浸し、十分に含浸させる。上記熱硬化性樹脂１７としてはフェノール樹脂が適する。
工程（ｇ）・・・熱硬化性樹脂１７の含浸直後、後工程の２次プレスを実施すると、金型に熱硬化性樹脂１７が貼り付いてしまい、プレス後に貼り合わせシート１５を剥がす時に割れや引きちぎれが発生して歩留まりが極度に低下する。逆に完全に乾燥させると成形性が悪くなって割れやすくなる。これを防止するために、乾燥炉（５０℃〜６０℃）に略１〜１０分間入れて熱硬化性樹脂１７を半乾燥状態（指で触ってもべたつかない程度の所謂“指触乾燥状態”である。）にする。
工程（ｈ）・・・前記工程（ｄ）と同様の周知の構成のプレス装置Ｐ２によって、含浸させた熱硬化性樹脂１７が半乾燥状態の貼り合わせシート１５を再度プレス加熱成形する。ここで２次プレス加熱成形の設定条件は、プレス圧力が略２０〜４０Ｋｇ、金型温度は上型３４が略８０〜２００℃、下型３５が略１００〜２００℃、プレス時間が略１０〜１００秒である。成形後は揮発成分が蒸散して成形形状が略ラッパ状に安定した貼り合わせシート１５となる。なお、この時点で重ね合わせて貼着された前記切り込み１１の縁部１１ａ、１１ｂ（斜線領域）同士はその段差が殆ど判別できない程度に密着しており、音響特性に与える影響は殆ど無いものとなっている。
工程（ｉ）・・・２次プレス後の貼り合わせシート１５の表裏両面に筆による塗布若しくはジャブ漬けにより防湿剤１８を塗布する。この防湿剤１８としては例えば、ポリイソシアネートとポリエステルポリオールを混合したものを用いる。なお、塗布された上記防湿剤１８は自然乾燥又は乾燥炉で完全乾燥を行なう。
工程（ｊ）・・・防湿処理されたプレス加熱成形後の貼り合わせシート１５にボイスコイル用の中心孔２５と外形抜きが施されて所定の振動板形状に加工されてスピーカ用振動板３０が完成する。
【００３５】
上記完成した略ラッパ状のスピーカ用振動板３０は、従来のダイナミック・スピーカと同様にボイスコイル、ダンパー、エッジ、磁気回路、フレーム等と組み合わされてスピーカユニットに組み込まれる。
【００３６】
上記本発明に係る第１の実施の形態のスピーカ用振動板３０の製造工程（Ｂ）では、略ラッパ形状に掛止保持する工程（ｄ１）を含んでいたが、前記掛止具２６を用いずとも、図１に示される請求項１に係る第２の実施の形態の（Ａ）のフローの製造方法の工程（ｄ）の１次プレス加熱成形時の直前に貼り合わせシート１５における成形領域（破線の円形部分内）以外の外周の余白部分における両縁部１１ａ、１１ｂ近傍を作業者が手で摘まんで保持した状態で１次プレス加熱成形することも可能である。また、予め切り込み１１の両縁部１１ａ、１１ｂ同士を重ねて接着剤で固着させる方法もあるが、音響特性に影響を与える接着剤は可及的に控えることが望ましい。そこで、工程（ｂ）において図５の（ａ）、（ｂ）、（ｃ）、（ｄ）に示されるような貼り合わせシート１５の略Ｖ字状の切り込み１１の両縁部１１ａ、１１ｂの近傍の破線で囲んだ円形の成形領域外の余白部分に互いに引っかける雄雌形状の掛止機構１９（１９ａ、１９ｂ）を設けることによって１次プレス加熱成形前に掛止保持しておく方法が適用できる。なお、１次プレス加熱成形の後は両縁部１１ａ、１１ｂ同士は自然状態で離れない程度に貼着されており、略ラッパ形状が保持される。
【００３７】
以上の製造方法によって製造されたスピーカ用振動板３０は、本発明者の研究によれば、縦方向伝搬速度が４．５〜６．０ｋｍ／秒、横方向伝搬速度が２．０〜４．５ｋｍ／秒の範囲の木材を選定して上記各実施の形態の製造方法にて製造された振動板が明確に従来の紙パルプ製の振動板やアルミ製の振動板に比べて再生音の解像度向上や歯切れ良い音の向上が得られることが判った。
【００３８】
特に顕著に音響特性の向上が実感されるのは、縦方向伝搬速度が４．５〜６．０ｋｍ／秒、横方向伝搬速度が２．０〜２．５ｋｍ／秒の範囲で内部損失係数が０．０２〜０．０３の範囲の木材を選択して振動板に用いた場合であり、具体的にはカバ材（無垢）が最良であった。
【００３９】
勿論、本発明のスピーカ用振動板は、カバのみならず、ブナ、オーク、チェリー、シナ等の他の材木を適用することもできることは勿論である。
【００４０】
【発明の効果】
上記のように本発明に係るスピーカ用振動板の製造方法は、１枚の木材を素材とし、従来の紙パルプ製振動板の製造過程に存在するような化学薬品での蒸解や木材繊維の叩解処理が加えられていないので音質劣化が発生しない振動板を作ることができる。
【００４１】
従来の木製振動板のような柔軟化のためのボイル処理、物理的処理、化学的薬品を施さないので音質劣化の発生しない振動板を作ることができる。
【００４２】
プレス加熱成形時のしわや割れの発生が防止され、製造後の変形や割れといった経時変化が殆ど無い仕上がりの良い均一なプレス加熱成形品とすることができる。
【００４３】
軽くて丈夫なコーン振動板が製造可能になり、ウーハーからフルレンジスピーカまで全ての帯域に対応した振動板が製造できる。
【００４４】
掛止具によってプレス加熱成形前から略ラッパ状に形状が保持されているため、プレス機へのセッティングの作業性が向上し、成形性の向上が実現して歩留まりが向上して、安価供給が実現できる。
【００４５】
本スピーカ用振動板がスピーカユニットに採用された際には、木製であるが故の自然な振動による生音に迫る再声音が経時変化なく出力される。
【００４６】
さらに、表面に自然の木目が表れているので、高級感のある外観体裁となる。
【図面の簡単な説明】
【図１】本発明に係る第１及び第２の実施の形態のスピーカ用振動板の成り立ちを説明するための製造工程フロー図である。
【図２】前記製造工程フロー図の各加工状態（前半）を示す模式図である。
【図３】前記製造工程フロー図の各加工状態（後半）を示す模式図である。
【図４】本発明に係るスピーカ用振動板の素材である木材の形状の加工段階を説明する模式図である。
【図５】本発明に係るスピーカ用振動板の貼り合わせシートに設けた略Ｖ字状の切り込み及び掛止機構の例を示す図である。
【図６】本発明に係るスピーカ用振動板の貼り合わせシートを掛止具によって略ラッパ形状に掛止保持した状態を示す図である。
【図７】本発明に係る略ラッパ形状のダイナミック・コーン・スピーカのスピーカ用振動板の概略図である。
【図８】従来の木製振動板の製造手順を示す図である。
【図９】従来の木製振動板の製造手順を示す図である。
【図１０】各種木材の有する内部損失係数と音伝搬速度（縦方向）についての関係を従来の材料であるアルミと紙と共に表したグラフである。
【符号の説明】
６ 丸太
７ 削り出し用刃
１０ 木製シート
１１ 略Ｖ字状の切り込み
１１ａ、１１ｂ 両縁部
１２ 小穴
１３ 不織布又は和紙
１４ 噛み合わせ掛止機構
１４ａ 凸部
１４ｂ 切欠部
１５ 貼り合わせシート
１６ 水分を与え且つ水分を保持する作用のある潤滑剤
１７ 熱硬化性樹脂
１８ 防湿剤
１９ 掛止機構
２５ 中心孔
２６ 掛止具
３０ スピーカ用振動板
３１、３４ 上型
３３ ヒータ
３２、３５ 下型
Ｐ１、Ｐ２ プレス装置[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of audio speakers, and particularly relates to a method of manufacturing a wooden diaphragm used for dynamic speakers.
[0002]
[Prior art]
Conventionally, most diaphragms of dynamic speakers are made of paper pulp, plastic, or metal such as aluminum. Since these conventional diaphragms are formed by pressing a uniform material, the sound propagation speed in the radial direction from the center is the same in all directions. Therefore, a standing wave always occurs and has a resonance point. This causes a problem that sound pressure frequency characteristics are deteriorated due to divided vibrations in a low frequency region, and a sense of reality is lost. Paper pulp and plastic diaphragms have a relatively large internal loss factor, but on the contrary, they are inferior in terms of rigidity (Young's modulus), and the sound propagation speed is low, so the resolution of the reproduced sound is somewhat unsatisfactory. Remain. On the other hand, although a metal diaphragm such as aluminum has a high sound wave propagation speed, the internal loss coefficient is small, so that the attenuation of amplitude is small and the division of reproduced sound is unclear (so-called sound sharpness is poor). .
[0003]
Instead of the existing diaphragms having the advantages and disadvantages as described above, it is desired to realize a wooden diaphragm as a diaphragm for a speaker that can reproduce a more natural sound.
[0004]
That is, the sound wave propagation speed of wood varies depending on the type, but is generally higher than that of paper pulp. Further, the propagation speed differs in the direction of the wood grain and the direction perpendicular thereto, and the propagation speed in the wood grain direction (referred to as the vertical direction) is fast and perpendicular to the grain The propagation velocity in the direction (referred to as the transverse direction) has an anisotropic propagation property that it is relatively slow. In addition, wood generally has an appropriate internal loss factor as a speaker diaphragm, and is light and strong (high rigidity).
[0005]
Therefore, a wooden diaphragm made of wood itself is unlikely to generate a standing wave and hardly has a resonance point. Therefore, divided vibration hardly occurs, and improvement of sound pressure frequency characteristics in a low frequency region is expected. Compared with a paper pulp diaphragm, the resolution of the reproduced sound can be improved and the sound can be improved crisply.
[0006]
Various proposals have already been made, for example, in the following publicly known literatures as methods for manufacturing the wooden diaphragm or the dynamic speaker using the wooden diaphragm or the wooden diaphragm.
[0007]
In the following [Patent Document 1], a flat plate made of WPC made by impregnating and hardening a plastic material such as polyester on a flat plate made of wood material is a flat plate diaphragm for a speaker excellent in characteristics such as dimensional stability, internal friction, and rigidity. The speaker used as is proposed.
[0008]
The following [Patent Document 2] has (a) an arc-shaped cutout portion 1a in the center from one piece of wood sheet 4 as in the manufacturing procedure shown in FIGS. 8 (a) and 8 (b). Then, the wood sheet 1 which is a substantially trumpet-shaped developed shape having a fan-shaped cutout portion 1b is cut out, and (b) both edges b1 and b2 of the fan-shaped cutout portion 1b of the wood sheet 1 are glued. A cone diaphragm 5 has been proposed which is formed in a trumpet shape by being overlapped and bonded to each other at an allowance portion 1c and then press-molded.
[0009]
Further, as in the manufacturing procedure shown in FIGS. 9A and 9B, a plurality of small pieces of wood 2a, 2b,... A cone diaphragm 2 formed and then press-molded has been proposed. Further, there has been proposed a cone diaphragm obtained by adding physical moisture resistance treatment or chemical moisture resistance treatment to the cone diaphragms 1 and 2.
[0010]
In the following [Patent Document 3], a composite sheet composed of an ultrathin wood sheet sliced to 80 μm or less and a non-woven fabric made of an adhesive resin attached to the back surface thereof is softened with a softening agent. Thus, there has been proposed an acoustic diaphragm in which a plurality of sheets are stacked and further heated and pressed to form a conical shape.
[0011]
In the following [Patent Document 4], a flat timber sheet cut into a fan shape is boiled with high-temperature steam, hot water, or an alkaline solution having a pH of 10 or more to prevent cracking during molding, and then conical. A cone diaphragm formed by press molding has been proposed.
[0012]
In the following [Patent Document 5], a laminated sheet in which a thin non-woven fabric or Japanese paper is pasted on one side of one wooden sheet is prepared, and this is impregnated into a container containing a lubricant, and the impregnated laminated sheet There has been proposed a loudspeaker diaphragm that is press-heated and formed into a substantially trumpet shape.
[0013]
The following [Patent Document 6] describes a thin non-woven fabric or Japanese paper on one side of one wooden sheet in order to produce a wooden speaker diaphragm that does not cause wrinkles or cracks during press molding and has little change over time. There has been proposed a speaker diaphragm in which a bonded sheet with a carbon sheet attached is prepared, impregnated with a thermosetting resin, and then press-heat molded to form a substantially trumpet shape.
[0014]
[Patent Document 1]
JP-A-62-2224196 [Patent Document 2]
JP-A-1-288100 [Patent Document 3]
JP-A-5-83792 [Patent Document 4]
JP-A-6-178386 [Patent Document 5]
JP-A-10-304492 [Patent Document 6]
JP 2000-59883 A [Problems to be solved by the invention]
The key point in the manufacture of wooden speaker diaphragms is how to cope with the property that wood is easily broken in molding and how to deal with secular change.
[0015]
In this respect, [Patent Document 1] is a flat plate diaphragm made of wood, and although the characteristics and advantages of being a wood are shown, the moldability when forming into a substantially trumpet shape (cone shape). Technical data on the problem is not provided because it is flat.
[0016]
Further, in the manufacturing method as shown in FIGS. 8 and 9 of [Patent Document 2], the wood sheet 1 or the wood piece sheets 2a, 2b,. Or cracking during press molding, or because the wood sheets are bonded to each other with an adhesive, there is a problem that the adhesive part becomes an obstacle and desired acoustic characteristics cannot be obtained, and dimensional accuracy cannot be secured. .
[0017]
In addition, the manufacturing method in which a plurality of ultra-thin wood sheets of [Patent Document 3] are laminated and press-molded has a difficulty in processing accuracy, and the adhesive layer increases and the weight of the diaphragm itself increases due to the weight of the adhesive. Therefore, the desired acoustic characteristics cannot be obtained, and a large amount of adhesive adversely affects the sound pressure frequency characteristics, which is not preferable.
[0018]
In addition, as in [Patent Document 4], in the case of a manufacturing process including boil treatment with high-temperature steam or an alkaline solution having a pH of 10 or more before press molding, a constituent material called lignin in the wood is also removed. The original characteristics of the sound cannot be exhibited, and the sound quality will be adversely affected.
[0019]
Above all, the contents of the above [Patent Document 2], [Patent Document 3], and [Patent Document 4] have many defects such as cracks, cracks and wrinkles during production, and the yield in mass production is very high. It is getting worse and not commercialized.
[0020]
In addition, in [Patent Document 5] and [Patent Document 6], a thermosetting resin is used to impregnate a lubricant for extracting “tension” and “flexibility”, prevent wrinkles and cracks from occurring, and prevent change over time. Although the speaker diaphragm manufacturing method in which press-molding is performed after impregnation has superiority in the manufacturing process for mass production as compared with the above [Patent Document 1] to [Patent Document 4], it is still sufficient for mass production. It is difficult to say that the establishment of the molding process has been achieved, and it is desired to further improve the yield of moldability and to achieve a beautifully finished wooden diaphragm toward the practical use of the wooden diaphragm.
[0021]
The present invention has been made in view of the above circumstances, and provides a method for manufacturing a wooden speaker diaphragm that is effective in improving the acoustic characteristics of a dynamic speaker and is suitable for mass production.
[0022]
[Means for Solving the Problems]
In order to solve the above problems, the present invention
(1) In a method for manufacturing a speaker diaphragm including a step of pressing a single wooden sheet into a substantially trumpet shape, first, a thin non-woven fabric or Japanese paper 13 is pasted on one side of one wooden sheet 10. A step of forming the laminated sheet 15 by wearing, a step of providing a substantially V-shaped cut 11 having a vertex at the center of the bonded sheet 15, and a step of forming the cut 11 third. Moisturizing and softening the laminated sheet 15 and including a lubricant 16 having an action of retaining moisture in the laminated sheet; and fourth, the laminated sheet 15 containing the lubricant 16 is primarily used. A step of press-molding to form a substantially trumpet shape in which the edges 11a and 11b of the cut are overlapped with each other, and a fifth step of drying the bonded sheet 15 that has been temporarily formed. And 6th, the step of including the thermosetting resin 17 in the bonded sheet 15 after drying, and 7th, the bonding sheet 15 including the thermosetting resin 17 in a semi-dry state. A step of drying at a drying temperature of 50 ° C. to 60 ° C. for approximately 1 to 10 minutes until semi-drying, and eighthly, a laminated sheet in which the thermosetting resin 17 is in a semi-dry state is subjected to secondary press thermoforming. However, the step of adhering the edges 11a, 11b of the substantially V-shaped notch 11 by the adhesive force of the thermosetting resin 17, and ninthly, the bonded sheet 15 after the secondary press thermoforming Applying the moisture-proofing agent 18 and tenthly, the laminated sheet 15 coated with the moisture-proofing agent 18 is formed with a voice coil center hole 25 and an outer shape, and formed into a predetermined size shape as a diaphragm. And a process of The provision to provide a method for manufacturing a speaker diaphragm 30, characterized in.
(2) In the method for manufacturing a speaker diaphragm including a step of press-molding a single wooden sheet 10 into a substantially trumpet shape, first, a thin non-woven fabric or Japanese paper on one surface side of the single wooden sheet 10 13, a step of creating a bonded sheet 15, a step of providing a substantially V-shaped cut 11 having a vertex at the center of the bonded sheet 15, and a third of the cut 11. A step of adding a lubricant to the provided laminated sheet 15 to soften it while containing the lubricant 16 having a function of retaining the moisture in the laminated sheet 15; and fourthly, a laminated sheet containing the lubricant 16 The edges 11a and 11b of the 15 notches 11 are overlapped with each other, and the portion outside the press forming region of the laminated sheet 15 is latched so that the whole is latched and held in a substantially trumpet shape. A step of stopping at 26, and fifth, a step of temporarily forming the laminated sheet 15 held in a substantially trumpet shape by the latching tool 26 and containing the lubricant 16 by primary press heat molding to a substantially trumpet shape, Sixth, the step of drying the temporarily formed bonded sheet 15, the seventh step of including the thermosetting resin 17 in the bonded sheet 15 after drying, and the eighth, the thermosetting resin 17. And the step of drying for about 1 to 10 minutes at a drying temperature of 50 ° C. to 60 ° C. until the pasted sheet 15 containing is contained in a semi-dry state, and ninth, the thermosetting resin 17 A step of adhering the substantially V-shaped cut edges 11a and 11b to each other by the adhesive force of the thermosetting resin 17 while secondarily press-molding a semi-dried laminated sheet; Secondary press thermoforming A step of applying the moisture-proofing agent 18 to the bonding sheet 15 and 11th, removing the voice coil center hole 25 and removing the outer shape from the bonding sheet 15 to which the moisture-proofing agent 18 is applied. The method for manufacturing the speaker diaphragm 30 is provided with a step of forming a predetermined dimensional shape.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a speaker diaphragm according to the present invention will be described with reference to the drawings. FIG. 1 is a flowchart of a manufacturing process of speaker diaphragms according to the first and second embodiments of the present invention. 2 and 3 are schematic views showing the first half and the second half of each processing state of the manufacturing process. FIG. 4 is a schematic diagram for explaining the processing stage of the shape of the wood that is the material of the speaker diaphragm according to the present invention. FIG. 5 is a view showing an example of a substantially V-shaped notching and latching mechanism provided on the bonded sheet of the speaker diaphragm according to the present invention. FIG. 6 is a view showing a state in which the bonded sheet of the speaker diaphragm according to the present invention is hooked and held in a substantially trumpet shape by a hooking tool. FIG. 7 is a schematic view of a speaker diaphragm of a substantially trumpet-shaped dynamic cone speaker according to the present invention.
[0024]
First, in FIG. 4, the wood that is the material of the speaker diaphragm 30 of the present invention is cut out from a wood log 6 by a rotary method as shown in FIG. Then, it is peeled thinly from the circumferential direction and cut into a suitable shape larger than the molded part (inside the broken-line circular part) that actually becomes the diaphragm as shown in FIG. For example, a dynamic cone speaker diaphragm having a diameter of about 8 cm is a square having a side of about 12 to 14 cm or a rectangle or a circle having a diameter of about 12 cm.
[0025]
Next, entering the manufacturing stage, the wooden sheet 10 becomes a laminated sheet 15 through the bonding process of the nonwoven fabric or Japanese paper 13 of FIG. 2 (a), as shown in FIG. 2 (b). A substantially V-shaped cut 11 is provided. The substantially V-shaped cut 11 may be not only a simple V-shape but also a sawtooth shape as shown in FIG. 5A or a wave shape as shown in FIG. In short, if the two edges are overlapped with no gap, the whole should have a substantially trumpet shape (cone shape).
[0026]
Next, after a number of press molding processes and the like, the speaker diaphragm 30 of the dynamic cone speaker having a substantially trumpet shape as shown in the schematic diagram of FIG. 7 is finally obtained (cross-sectional view of (j) of FIG. 3). See also).
[0027]
The wood grain of the speaker diaphragm 30 shown in FIG. 7 is only in the da direction along the grain direction when viewed in the radial direction (for example, the da to dh directions) from the center hole 25 cut out for the voice coil. However, the other direction intersects with the grain at a certain angle. Therefore, the same sound propagation speed does not exist in most directions, and standing waves are hardly generated and resonance points are hardly generated, so that divided vibration is suppressed.
[0028]
In addition, the speaker diaphragm 30 has excellent acoustic characteristics based on being made of wood and a beautiful finish of the wood, and the selected lubricant, thermosetting resin, impregnation with a moisture-proofing agent, and a series of press heating molding processes. By contrivance and the like, there are no wrinkles or cracks, the change with time due to humidity is small, and the life is long. It should be noted that the manufacturing process is simple but has a very good yield and is excellent in mass productivity with reduced manufacturing costs.
[0029]
Here, considering wood suitable for the material of the speaker diaphragm 30 of the present invention, the relationship between the internal loss coefficient and the sound propagation speed (longitudinal direction) of various kinds of wood in FIG. As shown in [Table 1] below, which shows the density, Young's modulus, sound velocity, and internal loss factor (tan δ) of the various woods, the plywood is roughly (G point, H point, I point, J point). It can be seen that the wood (solid material) except it can be an excellent material having an appropriate internal loss factor and high sound propagation speed. In particular, it is found that hip (point A) and beech (point C) are optimal.
[0030]
[Table 1]

In addition, A point in FIG. 10 is a hip (solid wood), and below, B point; China (solid wood), C point; Beech (solid wood), D point; Oak (solid wood), E point; Cherry (Solid wood), F point; spruce (solid wood), G point; China plywood (core), H point; Lauan plywood, I point; MFD, J point; particle board.
[0031]
Next, a method of manufacturing the speaker diaphragm 30 will be described with reference to a flowchart from (a) to (j) of FIG. 1 and schematic diagrams from (a) to (j) corresponding to FIGS. .
[0032]
First, as shown in FIG. 1, the manufacturing process of the speaker diaphragm 30 according to the first embodiment (B) according to claim 2 is performed in advance in the material preparation stage (p) after the production of the wooden sheet ( (a)-(j) is composed of 11 steps, (a) creating a laminated sheet, (b) forming a V-shaped cut, (c) impregnating with a lubricant, (d1) hanging in a substantially trumpet shape, d2) Primary press for temporary molding, (e) drying, (f) thermosetting resin impregnation, (g) semi-drying, (h) secondary press, (i) application of moisture-proofing agent, (j) center hole / outer shape The speaker diaphragm is completed in the order of removal.
[0033]
The detailed contents of the above steps will be described in the following order.
Step (a) ... 0. A non-woven fabric or Japanese paper 13 having a thickness of approximately 0.02 to 0.30 mm is bonded to one side of a wooden sheet 10 having a thickness of 1 mm to 0.9 mm (preferably about 0.3 mm) with an adhesive to create a bonded sheet 15. To do. The non-woven fabric here is a well-known material made of a carbon material or other synthetic resin, and the bonded one surface side is the back surface side of the completed diaphragm 30. The thickness of the wooden sheet 10 is an appropriate thickness for a speaker diaphragm in consideration of moldability, acoustic characteristics, and the diameter of a dynamic speaker.
Step (b): A substantially V-shaped cut 11 having a vertex at the center and a small hole 12 in the vicinity of the vertex are provided on the laminated sheet 15. The cuts 11 are provided substantially along the grain direction (arrow f) of the bonded sheet 15. The small hole 12 is for preventing cracking of the central portion when being formed into a substantially trumpet shape, and has a circular shape, an elliptical shape, a hexagonal shape or the like with a diameter of several millimeters, and the shape is not limited.
Step (c): In the liquid of the lubricant 16 that has the function of permeating into the bonding sheet 15 to give moisture and holding moisture so that the V-cut laminated sheet 15 is softened. Soak for 5-60 minutes and fully impregnate.
[0034]
This is in order to prevent the cracking in the subsequent primary press heat forming and to perform temporary forming with a high yield. According to the study of the present inventors, the lubricant 16 is not simply water or an alkaline aqueous solution, but an aqueous solution in which saccharides are dissolved.
Step (d1): the outer edges (margin portions) are hooked so that both edges 11a, 11b of the cut 11 of the bonded sheet 15 are overlapped to form a substantially trumpet shape as shown in FIG. The tool 26 is hooked and held. A paper binding device such as a stapler (trade name) or a clip can be used as the latching tool 26, and can be easily latched and held by stopping the marginal portion on the extension of the both edges 11a and 11b. The workability and processing accuracy of the next press thermoforming are improved.
Step (d2)... Affixed with the lubricant 16 impregnated and held in a substantially trumpet shape by the latch 26 by the press device P1 having the upper die 31 and the lower die 32 each having the heater 33. The laminated sheet 15 is subjected to primary press heat molding (temporary molding). Here, the setting conditions of the primary press thermoforming are as follows: the press pressure is approximately 1 to 10 kg, the mold temperature is approximately 80 to 150 ° C. for the upper die 31, approximately 100 to 200 ° C. for the lower die 32, and the press time is approximately 2 to 2. 60 seconds. In addition, since the shape is maintained in a substantially trumpet shape before being set in the press device P1 by the meshing engagement mechanism 14, the workability of the setting is improved and the primary press heat forming (temporary forming) is formed. The improvement of property (less wrinkles and cracks) has been realized.
Step (e): Complete drying is carried out in a drying furnace (50-60 ° C.) for about 10-30 minutes.
Step (f): The laminated sheet 15 after drying is immersed in the thermosetting resin 17 liquid for approximately 30 minutes to 180 minutes and sufficiently impregnated. As the thermosetting resin 17, a phenol resin is suitable.
Step (g): Immediately after impregnation with the thermosetting resin 17, if the secondary press in the subsequent step is carried out, the thermosetting resin 17 is stuck to the mold, and cracks occur when the laminated sheet 15 is peeled off after pressing. As a result, tearing occurs and the yield decreases extremely. On the other hand, when it is completely dried, the moldability deteriorates and it becomes easy to crack. In order to prevent this, the thermosetting resin 17 is placed in a drying oven (50 ° C. to 60 ° C.) for approximately 1 to 10 minutes in a semi-dried state (so-called “finger-dried state” that is not sticky to the touch) ).
Step (h): The laminated sheet 15 in which the impregnated thermosetting resin 17 is semi-dried is press-heated again by the press device P2 having a known configuration similar to the step (d). Here, the setting conditions of the secondary press thermoforming are as follows: the press pressure is approximately 20 to 40 kg, the mold temperature is approximately 80 to 200 ° C. for the upper die 34, approximately 100 to 200 ° C. for the lower die 35, and the press time is approximately 10 to 10 ° C. 100 seconds. After molding, the volatile component is evaporated, and the bonded sheet 15 is formed in a stable shape in a substantially trumpet shape. It should be noted that the edges 11a and 11b (shaded areas) of the cuts 11 that are overlapped and stuck at this point are in close contact with each other so that the level difference is hardly discernable, and there is almost no influence on the acoustic characteristics. It has become.
Step (i)... The moisture-proof agent 18 is applied to both the front and back surfaces of the bonded sheet 15 after the secondary press by brush application or jab immersion. As this moisture-proof agent 18, what mixed polyisocyanate and polyester polyol is used, for example. The applied moistureproof agent 18 is naturally dried or completely dried in a drying furnace.
Step (j)... The voice coil center hole 25 and the outer shape of the laminated sheet 15 after press thermoforming that has been subjected to moisture-proofing are cut out into a predetermined diaphragm shape, and the speaker diaphragm 30 is formed. Complete.
[0035]
The completed substantially trumpet-shaped speaker diaphragm 30 is assembled into a speaker unit in combination with a voice coil, a damper, an edge, a magnetic circuit, a frame, and the like in the same manner as a conventional dynamic speaker.
[0036]
The manufacturing process (B) of the speaker diaphragm 30 according to the first embodiment of the present invention includes the step (d1) of latching and holding in a substantially trumpet shape. At least, the forming region in the laminated sheet 15 immediately before the primary press thermoforming in the step (d) of the flow manufacturing method (A) of the second embodiment according to claim 1 shown in FIG. It is also possible to perform primary press thermoforming with the operator holding and holding the edges 11a and 11b in the marginal portion of the outer periphery other than (inside the broken-line circular portion) by hand. In addition, there is a method in which both edges 11a and 11b of the notch 11 are previously overlapped and fixed with an adhesive, but it is desirable to refrain as much as possible from an adhesive that affects the acoustic characteristics. Therefore, in the step (b), both edges 11a and 11b of the substantially V-shaped cut 11 of the laminated sheet 15 as shown in FIGS. 5 (a), (b), (c), and (d). A method of holding and holding before the primary press thermoforming by providing a male and female hooking mechanism 19 (19a, 19b) that hooks each other in the margin outside the circular forming area surrounded by the broken line in the vicinity is applied. it can. In addition, after primary press thermoforming, both edge parts 11a and 11b are stuck so that it may not leave | separate in a natural state, and a substantially trumpet shape is maintained.
[0037]
According to the present inventors' research, the speaker diaphragm 30 manufactured by the above manufacturing method has a longitudinal propagation velocity of 4.5 to 6.0 km / second and a lateral propagation velocity of 2.0 to 4. The vibration plate manufactured by the manufacturing method according to each of the above embodiments by selecting wood in the range of 5 km / second is clearly more reproducible than the conventional paper pulp diaphragm or aluminum diaphragm. It has been found that improvement and improvement in crisp sound can be obtained.
[0038]
The remarkable improvement in acoustic characteristics is particularly noticeable when the longitudinal propagation velocity is 4.5 to 6.0 km / sec and the lateral propagation velocity is 2.0 to 2.5 km / sec. This is the case where wood in the range of 0.02 to 0.03 is selected and used for the diaphragm, and specifically, the cover material (solid) is the best.
[0039]
Of course, the speaker diaphragm of the present invention can be applied not only to the hippo but also other timbers such as beech, oak, cherry, and china.
[0040]
【The invention's effect】
As described above, the speaker diaphragm manufacturing method according to the present invention uses a single piece of wood as a raw material, and digests with chemicals or beats wood fibers that exist in the process of manufacturing a conventional paper pulp diaphragm. Since no processing is applied, it is possible to make a diaphragm that does not cause deterioration in sound quality.
[0041]
Since a boil treatment, a physical treatment, and a chemical agent are not applied for softening like a conventional wooden diaphragm, a diaphragm that does not cause deterioration in sound quality can be produced.
[0042]
Occurrence of wrinkles and cracks during press thermoforming is prevented, and a uniform press thermoformed product having a good finish with little change over time such as deformation and cracking after production can be obtained.
[0043]
Light and durable cone diaphragms can be manufactured, and diaphragms can be manufactured for all bands from woofers to full-range speakers.
[0044]
Since the shape is held in a generally trumpet shape before press heat forming by the latch, the workability of setting to the press machine is improved, the formability is improved, the yield is improved, and the low cost supply is achieved. realizable.
[0045]
When this speaker diaphragm is adopted in a speaker unit, a re-voiced sound approaching a raw sound due to natural vibration because it is made of wood is output without change over time.
[0046]
Furthermore, the natural wood grain appears on the surface, so it has a high-quality appearance.
[Brief description of the drawings]
FIG. 1 is a manufacturing process flow chart for explaining the formation of speaker diaphragms according to first and second embodiments of the present invention.
FIG. 2 is a schematic diagram showing each processing state (first half) of the manufacturing process flow chart.
FIG. 3 is a schematic diagram showing each processing state (second half) of the manufacturing process flow chart.
FIG. 4 is a schematic diagram for explaining a processing stage of a shape of wood that is a material of a speaker diaphragm according to the present invention.
FIG. 5 is a view showing an example of a substantially V-shaped notching and latching mechanism provided in a bonded sheet of a speaker diaphragm according to the present invention.
FIG. 6 is a view showing a state in which the bonded sheet of the speaker diaphragm according to the present invention is hooked and held in a substantially trumpet shape by a hooking tool.
FIG. 7 is a schematic view of a speaker diaphragm of a substantially trumpet-shaped dynamic cone speaker according to the present invention.
FIG. 8 is a diagram showing a manufacturing procedure of a conventional wooden diaphragm.
FIG. 9 is a diagram showing a manufacturing procedure of a conventional wooden diaphragm.
FIG. 10 is a graph showing the relationship between the internal loss coefficient and sound propagation speed (longitudinal direction) of various kinds of wood together with aluminum and paper, which are conventional materials.
[Explanation of symbols]
6 Log 7 Cutting blade 10 Wooden sheet 11 V-shaped cuts 11a and 11b Both edges 12 Small holes 13 Non-woven fabric or Japanese paper 14 Engagement latching mechanism 14a Protrusion 14b Notch 15 Laminating sheet 16 Lubricant 17 that retains moisture 17 Thermosetting resin 18 Dehumidifier 19 Hook mechanism 25 Center hole 26 Hook 30 Speaker diaphragm 31, 34 Upper mold 33 Heater 32, 35 Lower mold P1, P2 Press device

Claims (2)

In the manufacturing method of the speaker diaphragm including the step of press-molding a single wooden sheet into a substantially trumpet shape,
First, a process of creating a laminated sheet by sticking a thin non-woven fabric or Japanese paper on one side of one wooden sheet, and second, a substantially V-shaped notch that reaches the center of the laminated sheet. A third step, a third step of adding moisture to the bonded sheet provided with the cut and softening it, and a step of including a lubricant having an action of retaining moisture in the bonded sheet; and fourth, the lubricant. And a step of temporarily forming the laminated sheet into a substantially trumpet shape in which the edges of the cuts are overlapped with each other and drying the temporarily formed laminated sheet. A step, a sixth step of including a thermosetting resin in the bonded sheet after drying, and a seventh step, from 50 ° C. until the bonded sheet containing the thermosetting resin is in a semi-dry state. 6 ℃ and a step of semi-drying is carried out dry approximately 10 minutes at a drying temperature of, the substantially V-shaped wherein the thermosetting resin while secondary press heat molding a bonded sheet of semidry state 8 A step of adhering the edges of the notches by the adhesive force of the thermosetting resin, a step of applying a moisture-proofing agent to the bonded sheet after the second press thermoforming, and a tenth of the moisture-proofing A diaphragm for a loudspeaker, comprising: a step of punching a voice coil center hole and an outer shape of a bonded sheet coated with an agent to form a predetermined shape as a diaphragm. Production method. In the manufacturing method of the speaker diaphragm including the step of press-molding a single wooden sheet into a substantially trumpet shape,
First, a process of creating a laminated sheet by sticking a thin non-woven fabric or Japanese paper on one side of one wooden sheet, and second, a substantially V-shaped notch that reaches the center of the laminated sheet. A third step, a third step of adding moisture to the bonded sheet provided with the cut and softening it, and a step of including a lubricant having an action of retaining moisture in the bonded sheet; and fourth, the lubricant. And a step of stopping the portion outside the press forming region of the laminated sheet with a latching tool so that the edges of the cuts of the laminated sheet containing each other are overlapped with each other and the whole is latched and held in a substantially trumpet shape. 5 is a step of first press-molding a laminated sheet that is held in a substantially trumpet shape by the latching tool and contains a lubricant, and temporarily formed into a substantially trumpet shape; Sea And drying the, until the step of including a thermosetting resin in the bonded sheet after drying the seventh, the bonding sheet the thermosetting resin is included in the eighth to half-dried state A step of drying for about 1 to 10 minutes at a drying temperature of 50 ° C. to 60 ° C. and semi-drying, and ninth, while the thermosetting resin is in a semi-dried state, the above-mentioned laminated sheet is subjected to hot press molding. A step of adhering edges of substantially V-shaped cuts by the adhesive force of the thermosetting resin, a step of applying a moisture-proofing agent to the bonded sheet after the second press thermoforming, 11. A speaker comprising: a step of forming a voice coil center hole and an outer shape of the laminated sheet on which the moisture-proofing agent is applied to 11 to form a predetermined size shape as a diaphragm. Method for manufacturing a diaphragm for an automobile.

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