【０００１】
【発明の属する技術分野】
本発明は、反転ばね及びその製造方法及びこれを用いたスイッチ装置に係り、携帯電話など小型の電子機器の押釦スイッチに好適な反転ばね及びその製造方法及びこれを用いたスイッチ装置の構造に関する。
【０００２】
【従来の技術】
従来の反転ばね及びこれを用いたスイッチ装置の構造としては、固定接点が形成された基台と、この基台上に固定接点と対向配置されたドーム状の反転部を有する反転ばねとから構成されている。
【０００３】
反転ばねは、上面側に押圧操作用のキートップが配設されて使用されるものとなっており、電子機器の化粧パネル側からこのキートップを押圧することにより、反転ばねの上面が押圧されて、下面に一体的に形成された接点部が反転して固定接点と接触することにより、接点の切り換えが行われるものである。
【０００４】
押圧操作用のキートップの下面には、ドーム状の反転ばねの頂部を押圧するための突起が一体形成されており、キートップが押圧されると、その押圧力がこの突起を介して反転ばねの頂部に伝達されるため、反転ばねがクリック感を伴って反転して固定接点に接触するものとなる。
【０００５】
この場合、キートップ下面の突起と、反転ばねのドーム頂部との間に相対位置のバラツキがあると、操作フィーリングに影響してくることから、これを解決するために、従来の構成においては、キートップ下面の突起の代りに、反転ばねの上面に樹脂で突起を形成することにより、キートップの押圧力を反転ばねのドーム頂部に伝達する構造が知られている（例えば、特許文献１）。
【０００６】
しかし、上記の反転ばね及びこれを用いたスイッチ装置の構造は、反転ばねのドーム頂部に印刷などにより樹脂を盛って突起を形成するため、突起の厚みのコントロールが難しく、精度良く形成することが困難であった。
そこで、本出願人は、反転ばねのドーム頂部に、金属材からなる突起部材をかしめて突起部を形成する構成の反転ばね（接点板）の出願を行った（特願２００２−０２９２６８号参照）。
【０００７】
この構造によれば、押圧部を容易に反転ばねの膨出部の頂部に形成でき、キートップとの相対位置ずれがあっても、反転ばねの膨出部の頂部に確実に押圧力を伝達することができ、良好なフィーリングが得られるものとなっている。
【０００８】
【特許文献１】
特開平１１−００７８６２号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、上述した従来の反転ばね及びこれを用いたスイッチ装置の構造においては、突起部の上面側をスイッチ操作時の押圧部として用いるため、押圧方向への反転ばねの突起部材の抜け強度を確保する必要があるが、突起部材のかしめ時の外形方向への肉の広がりを大きくできず、反転ばねと突起部材とのかしめ部の嵌合寸法を大きくできないことから、抜け強度が弱く押圧時に突起部が抜け落ちてしまうという問題があった。
【００１０】
したがって、本発明では上述した問題点を解決し、反転ばねへの突起部の形成を容易に行うことができると共に、突起部の抜けを防止し、信頼性の高い反転ばね及びその製造方法及びこれを用いたスイッチ装置を提供することを目的とする。
【００１１】
【課題を解決するための手段】
上記課題を解決するために本発明では第１の手段として、反転ばねは、反転可能な膨出部を有し、この膨出部の頂部に貫通孔が形成されたばね部材と、前記貫通孔に挿入され、一端が前記ばね部材の板厚方向の上面側に突出して保持された突起部材と、この突起部材の上面側に形成され、外部からの押圧力を伝達する押圧部とを備え、前記突起部材は、前記ばね部材の板厚方向の上下両面から挟み込むように前記突起部材の外周部を変形させて前記貫通孔に抜け止め保持されており、前記押圧部の中央部には薄肉状の凹部を形成し、前記押圧部の外周部の肉厚を前記押圧部の中央部の肉厚よりも厚くなるように形成したことを特徴とする。
【００１２】
また、第２の手段として、反転ばねは、前記突起部材を導電部材で形成すると共に、前記押圧部の他端側を前記ばね部材の膨出部の下面側に突出させて接点部を形成し、この接点部の表面に溝部を形成したことを特徴とする。
【００１３】
また、第３の手段として、反転ばねの製造方法は、板厚方向に貫通孔が形成された金属薄板からなるばね部材の前記貫通孔に、この板厚よりも厚い金属材からなる突起部材を挿入する工程と、上型と下型とで前記突起部材を挟み込んで加圧変形させることにより、前記突起部材の外周部を前記ばね部材の貫通孔の内縁に食い込ませて保持させる工程と、前記ばね部材をフォーミングして反転可能な膨出部を形成する工程とからなり、前記上型の前記突起部材との当接面の中央に凸部を形成し、前記突起部材の加圧変形時に、前記凸部によって前記突起部材の上面側の肉厚を中央部から外周部方向へ押し広げるようにしたことを特徴とする。
【００１４】
また、第４の手段として、反転ばねの製造方法は、前記下型の前記突起部材との当接面に突出部を形成し、前記突起部材の加圧変形時に、前記突出部によって前記突起部材の下面側の肉厚を外周部方向へ押し広げるようにしたことを特徴とする。
【００１５】
また、第５の手段として、スイッチ装置は、第１又は第２の手段に記載の反転ばねと、固定接点と、この固定接点と導通する外部接続端子が配設された基台とを備え、前記反転ばねの接点部を前記固定接点に対向させると共に、外部から前記押圧部を操作可能に前記基台上に配置したことを特徴とする。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を図１乃至図７に示す。図１は本発明の反転ばねの断面図、図２乃至図４は反転ばねの製造工程を示し、図２は突起部材のかしめ前の部分詳細図、図３はかしめ時の金型との関係を示す部分詳細図、図４はかしめ後の部分詳細図、図５は反転ばねを実装したスイッチ装置の平面図、図６は同じくスイッチ装置の断面図、図７は反転ばねを実装した他のスイッチ装置の一部を破断した分解斜視図である。
【００１７】
図１において、反転ばね１は、片面に銀めっきなどの表面処理が施されたりん青銅などの金属薄板を略円盤状に打ち抜いた導電性のばね部材から形成されており、その表面処理がなされた側を下面として外周縁部１ａから中心部に向かって所定角度で立ちあがるスカート部１ｂと、このスカート部１ｂに連続してドーム状に膨出した頂部１ｃとがプレスなどの方法で形成されている。また、前記頂部１ｃの中央には板厚方向に貫通する貫通孔１ｄが形成されており、この貫通孔１ｄ内には導電材料で略円柱状に形成された突起部材２が、前記貫通孔１ｄの上下方向に貫通した状態で抜け止め固定されている。
【００１８】
前記突起部材２の上面側には、外部からの押圧力を伝達す押圧部２ａが形成されており、また、下面側には、前記ばね部材の膨出部の下面側に突出させて接点部２ｂが形成されている。前記押圧部２ａの中央部には、円状の凹部２ｃが形成されており、この凹部２ｃを設けることにより、前記押圧部２ａの外周部の肉厚が、前記押圧部２ａの中央部の肉厚よりも厚くなるように形成されている。また、前記接点部２ｂの表面には、十字状の溝部２ｄが形成されており、この溝部２ｄによって複数に分割された四角部が突起状となって前記接点部２ｂの接点面を構成している。
【００１９】
次に、図２乃至図４で前記反転ばね１のばね部材へ前記突状部材２を固着する方法について説明する。
まず、図２に示すように、予め片面に銀めっきなどの表面処理が施された黄銅などの導電性の金属柱からなる突起部材２を、前記貫通孔１ｄの内径よりもわずかに小径となるように形成する。この場合、前記金属柱は接点面となる片面に銀めっきなどを施した金属板材を打ち抜いて形成するようにしても良い。そして、前記金属柱からなる突起部材２を略円盤状の外形に打ち抜かれた前記ばね部材の貫通孔１ｄ内に互いのめっき面が同一方向になるように配置する。
【００２０】
次に、図３に示すように、前記金属柱からなる突起部材２を上下方向から上型Ｊと下型Ｋとで挟み込んで加圧変形させることにより、前記突起部材２の外周部を前記ばね部材の貫通孔１ｄの内縁に食い込ませて抜け止めを形成し保持させる。また、同時に、前記突起部材の上面には前記押圧部２ａを、下面には前記接点部２ｂを形成する。
【００２１】
この時、前記上型Ｊの前記突起部材２の押圧部２ａとの当接面の中央には凸部Ｊａが形成されており、前記突起部材２の加圧変形時に、前記凸部Ｊａによって前記押圧部２ａの上面側の肉厚が中央部から外周部方向へ押し広げられるようになっている。そして、この結果、前記押圧部２ａの中央には円状の前記凹部２ｃが形成されるものとなる。
【００２２】
また、前記下型Ｋの前記突起部材２の接点部２ｂとの当接面には、加工時に、前記上型Ｊの凸部Ｊａと対応する位置に、十字状の突出部Ｋａが形成されており、前記突起部材２の加圧変形時に、前記突出部Ｋａによって前記突起部材２の下面側の肉厚が外周方向、すなわち、十字状の四角方向へ押し広げられるようになっている。そして、この結果、前記接点部２ｂには、十字状の前記溝部２ｄが形成され、この溝部２ｄによって複数に分割された四角部が突起状となって前記接点部２ｂの接点面を構成するものとなる。
【００２３】
これにより、図４に示すように、前記突起部材２は、前記ばね部材の板厚方向の上下両面から挟み込むように前記突起部材２の外周部を変形させて前記ばね部材の貫通孔１ｄに抜け止め保持されるものとなる。
そして、このようにして前記突起部材２が一体化された前記ばね部材を、図示しないプレス金型によって絞り加工することにより、前記ばね部材に前記スカート部１ｂと頂部１ｃとを有するドーム状の膨出部が形成されて前記反転ばね１が形成されるものとなっている。
【００２４】
このように、予め前記ばね部材に前記突起部材２を一体化しておき、しかる後に前記ばね部材をプレス成形してドーム状に形成することにより、反転可能な膨出部と外部からの押圧部２ａを精度良く形成することができる。また、前記突状部材２を導電材料で形成することにより、前記押圧部２ａに対して前記接点部２ｂをも精度良く形成することができる。
【００２５】
上記のようにして形成された前記反転ばね１は、前記外周縁部１ａの下面を被支持面として後述する周辺固定接点上に配置されて、前記押圧部２ａの外部からの押圧によって前記頂部１ｃが反転して、前記接点部２ｂが中央固定接点と接触可能となっている。また、前記反転ばね１は、ばね部材と突起部材２とが互いの表面処理が施された側が下面側になるように一致させて一体化されているので、固定接点に接触する前記外周縁部１ａの下面及び前記接点部２ｂとが銀メッキなどの表面処理面となるため、接点間の導通を確実に行うことができる。
【００２６】
上述した前記反転ばね１の製造方法によれば、前記上型Ｊの、前記突起部材２との当接面の中央に前記凸部Ｊａを形成し、前記突起部材２の加圧変形時に、前記凸部Ｊａによって、前記突起部材２の上面側の肉厚を中央部から外周部方向へ押し広げるようにしたので、加圧用の前記上型Ｊに前記凸部Ｊａを設けるだけの簡易な方法で、前記突起部材２のかしめ時の外形方向への肉の広がりを大きくできるので、前記ばね部材と突起部材２とのかしめ部の嵌合寸法（食い込み量）を増やすことができ、押圧時にばね部材から突起部材２が抜けてしまうのを防止することができるものとなる。
【００２７】
また、前記下型Ｋの前記突起部材２との当接面に前記突出部Ｋａを形成し、前記突起部材２の加圧変形時に、前記突出部Ｋａによって前記突起部材２の下面側の肉厚を外周部方向へ押し広げるようにしたので、加圧用の前記下型Ｋに前記突出部Ｋａを設けるだけの簡易な方法で、前記溝部２ｄの周りに多数の接触ポイントを有する前記接点部２ｂを精度良く形成できるものとなっている。
尚、前記溝部２ｄの形状は十字状に限らず、Ｙ字状や、横断する直線状、円形状としても良い。いずれにおいても、溝部２ｄの中心が凹部２ｃを形成する上型Ｊの凸部Ｊａと対応するように形成することで、溝部２ｄのエッジ形状を中心部から外周部にかけて確実に転写できる。
また、前記溝部２ｄを設けずに、接点部２ｂを平坦状に形成しても良い。この場合であっても、前記凹部２ｃによって突出部材２の外周部方向への肉厚を反転ばね１の上面側が大きく広がるように形成できる。
【００２８】
次に、図５及び図６で前記反転ばね１を実装したスイッチ装置の構成について説明する。図５及び図６は、上記した反転ばね１を単キースイッチとして構成した場合の押釦スイッチの構成を示す。
【００２９】
押釦スイッチ１０の基台としてのハウジング１１は合成樹脂などの絶縁材からなり、矩形状の底板部１１ａの外周を環状に取り囲んで起立する側壁１１ｂによって上部が開放された箱状の収納部１２が形成されている。そして、このハウジング１１の底板部１１ａには、導電性の金属材からなる一対の端子材がインサート成形されており、その一端が底板部１１ａ内で屈曲されて前記収納部１２内に突出して中央固定接点１６ａが形成されている。
また、他方の端子材の一端は、底板部１１ａ内で二股に分岐して各々が前記収納部１２内に中央固定接点１６ａを挟んで突出して一対の周辺固定接点１６ｂが設けられている。
【００３０】
中央固定接点１６ａは、ハウジング１１の収納部１２の略中央に位置し、収納部１２への底板部１１ａからの突出量が、中央固定接点１６ａに対して周辺固定接点１６ｂが若干高くなるように形成されている。
そして、中央固定接点１６ａに接続した端子材の他端部は、ハウジング１１外に導出されて前記側壁１１ｂに沿って曲げられ面実装用の半田付け部を有する外部接続端子１５ａが形成されている。同様に、周辺固定接点１６ｂに接続した端子材の他端部には、面実装用の半田付け部を有する外部接続端子１５ｂが形成されている。
【００３１】
そして、前記反転ばね１が前記ハウジング１１の凹状の収納部１２に収容され、その外周縁部１ａが周辺固定接点１６ｂ上に載置されて常時接触すると共に、接点部２ｂが中央固定接点１６ａ上に接離可能に対向配置されて可動接点を形成している。また、前記ハウジング１１内に収納された前記反転ばね１は、押圧部２ａを開口から突出させて、その上面が絶縁性の粘着シート１３によって覆われている。そして、前記粘着シート１３の貼付けしろ１３ａが前記ハウジング１１の上面に粘着層によって固着されて外部からの塵埃の侵入を防止している。
【００３２】
次に、上記構成の押釦スイッチ１０の動作について説明する。
押釦スイッチ１０の押圧部２ａの非押圧時には、前記反転ばね１のばね力によって、中央固定接点１６ａと接点部２ｂとは離間しており、スイッチは電気的にオフ状態となっている。
【００３３】
この状態から、前記押圧部２ａが図示しないキートップなどで押圧操作されると、粘着シート１３を撓ませながら反転ばね１が座屈反転してクリック感を創出すると共に、中央固定接点１６ａと接点部２ｂとが接触し、スイッチが電気的にオン状態となり、外部接続端子１５ａ、１５ｂを通じて、電子機器へ信号が送出されるものとなる。
【００３４】
この時、前記反転ばね１の頂部１ｃには、前記押圧部２ａが形成されているため、キートップの取り付け誤差や、押圧時の傾きなどにより、反転ばね１の頂部との相対位置ずれが発生したとしても、キートップからの押圧力を反転ばね１に確実に付与でき、良好な操作フィーリングが得られるものとなっている。
【００３５】
図７に示すのは、前記反転ばね１を固定接点が形成された接点基板上に多数実装してシート状スイッチ装置を構成したものである。
シート状スイッチ装置４０における基台としての接点基板３０は、絶縁性の樹脂などの積層板から形成されており、その表面に銅箔や、カーボンなどにより複数組みの固定接点３１が形成されている。この固定接点３１は、環状に形成された周辺固定接点３１ｂの内側に離間させて中央固定接点３１ａが配設されてなり、各々が接続パターンによって外部端子に接続されている。そして、この周辺固定接点３１ｂに上記反転ばね１の外周縁部１ａが常時導通可能に載置されると共に、反転ばね１の接点部２ｂが中央固定接点３１ａ上に接離可能に対向配置されて可動接点を形成している。
【００３６】
また、反転ばね１は、押圧部２ａを設けた側が、下面に粘着層を形成した絶縁性の可撓性粘着シート３５によって覆われている。そして、粘着シート３５の貼付けしろ３５ａに形成された粘着層によって、接点基板３０の上面に固着されてシート状スイッチ装置４０が形成されると共に、接点部内への外部からの塵埃の侵入を防止している。
【００３７】
上記のように構成されたシート状スイッチ装置４０は、可撓性粘着シート３５の上面にキートップを配置して電子機器に組み込まれるが、この組込み時にキートップと反転ばね１との相対位置にずれが生じたとしても、キートップからの押圧力を押圧部２ａを介して反転ばね１に確実に付与でき、良好な操作フィーリングが得られるものとなっている。
尚、上記実施例では、粘着シート３５によって押圧部２ａの上面をも覆うようにしたが、これに代えて、粘着シート３５に開口部を形成して、この開口部を介して、押圧部２ａを粘着シート３５の上面に突出させるように形成しても良い。
【００３８】
上述した、本発明の実施例の構成によれば、反転ばね１は、前記突起部材２が、ばね部材の板厚方向の上下両面から挟み込むように突起部材２の外周部を変形させて前記貫通孔１ｄに抜け止め保持されており、さらに前記押圧部２の中央部には薄肉状の前記凹部２ｃを形成し、前記押圧部２の外周部の肉厚を前記押圧部２の中央部の肉厚よりも厚くなるように形成したので、前記突起部材２のかしめ時の外形方向への肉の広がりを大きくできるため、前記ばね部材と突起部材２とのかしめ部の嵌合寸法（食い込み量）を増やすことができ、キートップなどで前記押圧部２が押圧された時に、前記突起部材２が抜け落ちてしまうのを防止することができるものとなっている。
【００３９】
また、前記突起部材２を導電性の金属材料で形成すると共に、前記押圧部２ａの他端側を前記ばね部材の膨出部の下面側に突出させて前記接点部２ｂを形成し、この接点部２ｂの表面に前記溝部２ｄを形成したので、前記溝部２ｄの周りに多数の接触ポイントを有する前記接点部２ｂが形成されるため、前記中央固定接点１６ａ及び３１ａとの接触信頼性の向上が図れる反転ばねが得られるものとなっている。
【００４０】
【発明の効果】
以上説明したように、本発明の反転ばねは、反転可能な膨出部を有し、この膨出部の頂部に貫通孔が形成されたばね部材と、貫通孔に挿入され、一端がばね部材の板厚方向の上面側に突出して保持された突起部材と、この突起部材の上面側に形成され、外部からの押圧力を伝達する押圧部とを備え、突起部材は、ばね部材の板厚方向の上下両面から挟み込むように突起部材の外周部を変形させて貫通孔に抜け止め保持されており、押圧部の中央部には薄肉状の凹部を形成し、押圧部の外周部の肉厚を前記押圧部の中央部の肉厚よりも厚くなるように形成したことから、突起部材のかしめ時の外形方向への肉の広がりを大きくできるので、ばね部材と突起部材とのかしめ部の嵌合寸法（食い込み量）を増やすことができ、押圧時に突起部材が抜け落ちてしまうのを防止することができ、信頼性を向上できる。
【００４１】
また、突起部材を導電部材で形成すると共に、押圧部の他端側をばね部材の膨出部の下面側に突出させて接点部を形成し、この接点部の表面に溝部を形成したことから、溝部の周りに多数の突起状の接点部が形成されるので、固定接点との接触信頼性の向上が図れる反転ばねが得られる。
【００４２】
また、反転ばねの製造方法は、板厚方向に貫通孔が形成された金属薄板からなるばね部材の貫通孔に、この板厚よりも厚い金属材からなる突起部材を挿入する工程と、上型と下型とで突起部材を挟み込んで加圧変形させることにより、突起部材の外周部をばね部材の貫通孔の内縁に食い込ませて保持させる工程と、ばね部材をフォーミングして反転可能な膨出部を形成する工程とからなり、上型の突起部材との当接面の中央に凸部を形成し、突起部材の加圧変形時に、凸部によって突起部材の上面側の肉厚を中央部から外周部方向へ押し広げるようにしたことから、加圧用の上型に凸部を設けるだけの簡易な方法で、突起部材のかしめ時の外形方向への肉の広がりを大きくできるので、ばね部材と突起部材とのかしめ部の嵌合寸法（食い込み量）を増やすことができる。
【００４３】
また、下型の突起部材との当接面に突出部を形成し、突起部材の加圧変形時に、突出部によって突起部材の下面側の肉厚を外周部方向へ押し広げるようにしたことから、加圧用の下型に突出部を設けるだけの簡易な方法で、溝部の周りに多数の接触ポイントを持つ接点部を精度良く形成できる。
【００４４】
また、スイッチ装置は、第１又は第２の手段に記載の反転ばねと、固定接点と、この固定接点と導通する外部接続端子が配設された基台とを備え、反転ばねの接点部を固定接点に対向させると共に、外部から押圧部を操作可能に基台上に配置したことから、キートップと反転ばねとの間に相対位置ずれが生じた場合であっても、反転ばねの膨出部の頂部へキートップの押圧力を確実に伝達することができ、良好な操作フィーリングを得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施例である反転ばねを示す断面図である。
【図２】本発明の突起部材のかしめ前の状態を示す部分詳細図である。
【図３】本発明の突起部材のかしめ時の金型との関係を示す部分詳細図である。
【図４】本発明の突起部材のかしめ後の状態を示す部分詳細図である。
【図５】本発明の反転ばねを実装したスイッチ装置を示す平面図である。
【図６】本発明の反転ばねを実装したスイッチ装置を示す断面図である。
【図７】本発明の反転ばねを実装した他のスイッチ装置の一部を破断した状態を示す分解斜視図である。
【符号の説明】
１ 反転ばね（ばね部材）
１ａ 外周縁部
１ｂ スカート部
１ｃ 頂部
１ｄ 貫通孔
２ 突起部材
２ａ 押圧部
２ｂ 接点部
２ｃ 凹部
２ｄ 溝部
１０ 押釦スイッチ
１１ ハウジング
１１ａ 底板部
１１ｂ 側壁
１２ 収納部
１３ 粘着シート
１３ａ 貼付けしろ
１５ａ，１５ｂ 外部接続端子
１６ 固定接点
１６ａ 中央固定接点
１６ｂ 周辺固定接点
３０ 接点基板
３１ 固定接点
３１ａ 中央固定接点
３１ｂ 周辺固定接点
３５ 可撓性粘着シート
３５ａ 貼付けしろ
４０ シート状スイッチ装置
Ｊ 上型
Ｊａ 凸部
Ｋ 下型
Ｋａ 突出部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reversing spring, a method of manufacturing the same, and a switch device using the same, and more particularly, to a reversing spring suitable for a push button switch of a small electronic device such as a mobile phone, a method of manufacturing the same, and a structure of a switch device using the same.
[0002]
[Prior art]
The structure of a conventional reversing spring and a switch device using the same includes a base on which a fixed contact is formed, and a reversing spring having a dome-shaped reversing portion disposed on the base so as to face the fixed contact. Have been.
[0003]
The reversing spring has a key top for pressing operation disposed on the upper surface side and is used. By pressing the key top from the decorative panel side of the electronic device, the upper surface of the reversing spring is pressed. Thus, the contact portion integrally formed on the lower surface is inverted and comes into contact with the fixed contact, thereby switching the contact.
[0004]
A projection for pressing the top of the dome-shaped reversing spring is integrally formed on the lower surface of the key top for pressing operation, and when the key top is pressed, the pressing force is applied to the reversing spring via the projection. , The reversing spring reverses with a click feeling and comes into contact with the fixed contact.
[0005]
In this case, if there is a variation in the relative position between the projection on the lower surface of the key top and the dome top of the reversing spring, the operation feeling is affected. There is known a structure in which a pressing force of a key top is transmitted to a dome top of a reversing spring by forming a projection on the upper surface of the reversing spring with a resin instead of the protrusion on the lower surface of the key top (for example, Patent Document 1). ).
[0006]
However, in the structure of the above-described reversing spring and the switch device using the same, since the protrusion is formed by applying resin on the top of the dome of the reversing spring by printing or the like, it is difficult to control the thickness of the protrusion, and it is difficult to form the protrusion with high precision. It was difficult.
Therefore, the present applicant has filed an application for a reversing spring (contact plate) having a configuration in which a protruding portion is formed by caulking a protruding member made of a metal material on the dome top of the reversing spring (see Japanese Patent Application No. 2002-029268). .
[0007]
According to this structure, the pressing portion can be easily formed on the top of the bulging portion of the reversing spring, and even if there is a relative displacement with the key top, the pressing force is reliably transmitted to the top of the bulging portion of the reversing spring. And a good feeling can be obtained.
[0008]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-007862
[Problems to be solved by the invention]
However, in the above-described conventional reversing spring and the structure of the switch device using the same, since the upper surface side of the protruding portion is used as a pressing portion at the time of operating the switch, the pull-out strength of the protruding member of the reversing spring in the pressing direction is secured. However, since the width of the flesh in the outer shape direction at the time of caulking of the protruding member cannot be increased, and the fitting dimension of the caulked portion between the reversing spring and the protruding member cannot be increased, the detachment strength is weak and the protruding portion is pressed. There was a problem that the part fell off.
[0010]
Therefore, the present invention solves the above-mentioned problems, facilitates formation of the protrusion on the reversing spring, prevents the protrusion from coming off, and provides a highly reliable reversing spring and a method of manufacturing the same. It is an object of the present invention to provide a switch device using the same.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the present invention, as a first means, a reversing spring has a reversible swelling portion, and a spring member having a through-hole formed at the top of the swelling portion; A protruding member which is inserted and one end of which is protruded and held on the upper surface side in the plate thickness direction of the spring member, and a pressing portion formed on the upper surface side of the protruding member and transmitting a pressing force from the outside; The projecting member deforms an outer peripheral portion of the projecting member so as to be sandwiched from both upper and lower surfaces in the plate thickness direction of the spring member, and is retained in the through-hole so as to be retained. A recess is formed, and a thickness of an outer peripheral portion of the pressing portion is formed to be larger than a thickness of a central portion of the pressing portion.
[0012]
Further, as a second means, the reversing spring forms the contact member by forming the projecting member from a conductive member and projecting the other end of the pressing portion toward the lower surface of the bulging portion of the spring member. A groove is formed on the surface of the contact portion.
[0013]
As a third means, the method for manufacturing a reversing spring is as follows: a projecting member made of a metal material having a thickness greater than the plate thickness is provided in the through hole of the spring member made of a thin metal plate having a through hole formed in the plate thickness direction. Inserting, and pressing and deforming the projection member by sandwiching the projection member between an upper mold and a lower mold, thereby causing an outer peripheral portion of the projection member to bite into an inner edge of a through hole of the spring member to be held; and Forming a reversible bulging portion by forming a spring member, forming a convex portion at the center of the contact surface of the upper die with the projecting member, and when pressing and deforming the projecting member, The thickness of the upper surface side of the projection member is pushed from the central portion toward the outer peripheral portion by the convex portion.
[0014]
As a fourth means, in the method of manufacturing a reversing spring, a projecting portion is formed on a contact surface of the lower mold with the projecting member, and the projecting member is formed by the projecting portion when the projecting member is deformed under pressure. Characterized in that the thickness of the lower surface side is pushed out toward the outer peripheral portion.
[0015]
Further, as a fifth means, the switch device includes the reversing spring according to the first or the second means, a fixed contact, and a base provided with an external connection terminal electrically connected to the fixed contact, A contact portion of the reversing spring is opposed to the fixed contact, and the pressing portion is operably arranged on the base from outside.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention is shown in FIGS. FIG. 1 is a sectional view of the reversing spring of the present invention, FIGS. 2 to 4 show a manufacturing process of the reversing spring, FIG. 2 is a partial detailed view of the projecting member before caulking, and FIG. 4, FIG. 4 is a partially detailed view after caulking, FIG. 5 is a plan view of a switch device equipped with a reversing spring, FIG. 6 is a cross-sectional view of the same switching device, and FIG. FIG. 3 is an exploded perspective view in which a part of the switch device is broken.
[0017]
In FIG. 1, a reversing spring 1 is formed of a conductive spring member formed by stamping a thin metal plate such as phosphor bronze having a surface treatment such as silver plating on one surface into a substantially disk shape, and the surface treatment is performed. A skirt portion 1b that rises at a predetermined angle from the outer peripheral edge portion 1a toward the center portion with the side facing the lower surface and a top portion 1c that protrudes in a dome shape continuously from the skirt portion 1b are formed by a method such as pressing. I have. A through-hole 1d is formed at the center of the top 1c in the thickness direction, and a projecting member 2 formed of a conductive material in a substantially cylindrical shape is formed in the through-hole 1d. Is secured in such a way that it penetrates vertically.
[0018]
A pressing portion 2a for transmitting a pressing force from the outside is formed on the upper surface side of the projecting member 2, and a contact portion is formed on the lower surface side so as to project toward the lower surface side of the bulging portion of the spring member. 2b is formed. A circular concave portion 2c is formed at the center of the pressing portion 2a. By providing the concave portion 2c, the thickness of the outer peripheral portion of the pressing portion 2a is reduced at the central portion of the pressing portion 2a. It is formed so as to be thicker than the thickness. A cross-shaped groove 2d is formed on the surface of the contact portion 2b, and the quadrangular portion divided into a plurality by the groove 2d forms a projection to form a contact surface of the contact portion 2b. I have.
[0019]
Next, a method of fixing the protruding member 2 to the spring member of the reversing spring 1 will be described with reference to FIGS.
First, as shown in FIG. 2, the protrusion member 2 made of a conductive metal column such as brass, which has been subjected to a surface treatment such as silver plating on one surface in advance, has a slightly smaller diameter than the inner diameter of the through hole 1 d. It is formed as follows. In this case, the metal column may be formed by punching a metal plate material having one side serving as a contact surface and having silver plating applied thereto. Then, the protruding member 2 made of the metal column is disposed in the through hole 1d of the spring member punched into a substantially disk-shaped outer shape so that the plating surfaces thereof are in the same direction.
[0020]
Next, as shown in FIG. 3, the outer peripheral portion of the projecting member 2 is subjected to the spring by sandwiching the projecting member 2 made of the metal column between the upper mold J and the lower mold K from above and below and pressing and deforming the same. The inner edge of the through hole 1d of the member is bitten to form and hold a stopper. At the same time, the pressing portion 2a is formed on the upper surface of the projection member, and the contact portion 2b is formed on the lower surface.
[0021]
At this time, a convex portion Ja is formed in the center of the contact surface of the upper die J with the pressing portion 2a of the projecting member 2, and when the projecting member 2 is deformed under pressure, the convex portion Ja causes The thickness of the pressing portion 2a on the upper surface side can be expanded from the central portion toward the outer peripheral portion. As a result, the circular concave portion 2c is formed at the center of the pressing portion 2a.
[0022]
A cross-shaped protrusion Ka is formed on a contact surface of the lower die K with the contact portion 2b of the protrusion member 2 at a position corresponding to the protrusion Ja of the upper die J during processing. In addition, when the protrusion member 2 is deformed under pressure, the thickness of the lower surface side of the protrusion member 2 is pushed outward in the outer peripheral direction, that is, in the cross-shaped square direction by the protrusion portion Ka. As a result, the contact portion 2b is formed with the cross-shaped groove 2d, and the quadrangular portion divided by the groove 2d into a plurality of protrusions forms a contact surface of the contact portion 2b. It becomes.
[0023]
Thereby, as shown in FIG. 4, the projecting member 2 deforms the outer peripheral portion of the projecting member 2 so as to be sandwiched from both the upper and lower surfaces in the thickness direction of the spring member, and comes out through the through hole 1d of the spring member. It will be stopped and held.
Then, the spring member integrated with the projection member 2 is drawn by a press die (not shown), so that the spring member has a dome-shaped expansion having the skirt portion 1b and the top portion 1c. An extension is formed to form the reversing spring 1.
[0024]
As described above, the projection member 2 is integrated with the spring member in advance, and then the spring member is press-formed to form a dome shape, whereby the reversible bulging portion and the pressing portion 2a from the outside are formed. Can be accurately formed. In addition, by forming the protruding member 2 from a conductive material, the contact portion 2b can be formed with high accuracy with respect to the pressing portion 2a.
[0025]
The reversing spring 1 formed as described above is disposed on a peripheral fixed contact, which will be described later, with the lower surface of the outer peripheral edge portion 1a as a supported surface, and the top portion 1c is pressed by the pressing portion 2a from outside. Are reversed, so that the contact portion 2b can contact the central fixed contact. In addition, since the reversing spring 1 is integrated such that the side on which the surface treatment is performed is the lower side, the spring member and the projecting member 2 are integrated with each other. Since the lower surface of 1a and the contact portion 2b are surface treated surfaces such as silver plating, conduction between the contacts can be reliably performed.
[0026]
According to the method of manufacturing the reversing spring 1 described above, the convex portion Ja is formed at the center of the contact surface of the upper mold J with the projecting member 2, and when the projecting member 2 is deformed under pressure, the convex portion Ja is formed. The thickness of the upper surface side of the protruding member 2 is pushed and widened from the central portion toward the outer peripheral portion by the protruding portion Ja. Therefore, a simple method of merely providing the protruding portion Ja on the upper die J for pressurization is provided. Since the thickness of the projecting member 2 in the outer shape direction at the time of caulking can be increased, the fitting dimension (bite amount) of the caulked portion between the spring member and the projecting member 2 can be increased, and the spring member can be pressed at the time of pressing. It is possible to prevent the protrusion member 2 from coming off from.
[0027]
Further, the projecting portion Ka is formed on a contact surface of the lower mold K with the projecting member 2, and when the projecting member 2 is deformed under pressure, the thickness of the lower surface side of the projecting member 2 is increased by the projecting portion Ka. The contact portion 2b having a large number of contact points around the groove 2d can be formed by a simple method of providing the projecting portion Ka on the lower die K for pressurization. It can be formed with high accuracy.
The shape of the groove 2d is not limited to the cross shape, but may be a Y-shape, a crossing straight line, or a circle. In any case, by forming the center of the groove 2d so as to correspond to the protrusion Ja of the upper die J forming the recess 2c, the edge shape of the groove 2d can be reliably transferred from the center to the outer periphery.
Further, the contact portion 2b may be formed flat without providing the groove 2d. Even in this case, the thickness of the protruding member 2 in the direction of the outer peripheral portion can be formed so that the upper surface side of the reversing spring 1 is greatly widened by the concave portion 2c.
[0028]
Next, the configuration of the switch device on which the reversing spring 1 is mounted will be described with reference to FIGS. FIGS. 5 and 6 show the configuration of the push button switch when the above-described reversing spring 1 is configured as a single key switch.
[0029]
A housing 11 as a base of the push button switch 10 is made of an insulating material such as a synthetic resin, and has a box-shaped storage portion 12 whose upper portion is opened by a side wall 11b which stands around the outer periphery of a rectangular bottom plate portion 11a in a ring shape. Is formed. A pair of terminal materials made of a conductive metal material are insert-molded in the bottom plate portion 11a of the housing 11, and one end thereof is bent in the bottom plate portion 11a and protrudes into the storage portion 12 so as to be centered. A fixed contact 16a is formed.
One end of the other terminal material is bifurcated in the bottom plate portion 11a, and each is provided with a pair of peripheral fixed contacts 16b protruding into the housing portion 12 with the central fixed contact 16a interposed therebetween.
[0030]
The central fixed contact 16a is located substantially at the center of the storage portion 12 of the housing 11, and the amount of protrusion from the bottom plate portion 11a into the storage portion 12 is such that the peripheral fixed contact 16b is slightly higher than the central fixed contact 16a. Is formed.
The other end of the terminal material connected to the central fixed contact 16a is led out of the housing 11 and bent along the side wall 11b to form an external connection terminal 15a having a soldering portion for surface mounting. . Similarly, an external connection terminal 15b having a soldering part for surface mounting is formed at the other end of the terminal material connected to the peripheral fixed contact 16b.
[0031]
The reversing spring 1 is accommodated in the concave accommodating portion 12 of the housing 11, the outer peripheral edge portion 1a is placed on the peripheral fixed contact 16b and is always in contact, and the contact portion 2b is located on the central fixed contact 16a. The movable contact is formed so as to be able to contact and separate from the movable contact. Further, the reversing spring 1 housed in the housing 11 has the pressing portion 2 a protruding from the opening, and the upper surface thereof is covered with the insulating adhesive sheet 13. And, a sticking margin 13a of the adhesive sheet 13 is fixed to the upper surface of the housing 11 by an adhesive layer to prevent intrusion of dust from the outside.
[0032]
Next, the operation of the push button switch 10 having the above configuration will be described.
When the pressing portion 2a of the push button switch 10 is not pressed, the center fixed contact 16a and the contact portion 2b are separated by the spring force of the reversing spring 1, and the switch is in an electrically off state.
[0033]
In this state, when the pressing portion 2a is pressed by a key top or the like (not shown), the reversing spring 1 buckles while bending the adhesive sheet 13 to create a click feeling, and the center fixed contact 16a and the contact The switch is electrically turned on by contact with the portion 2b, and a signal is transmitted to the electronic device through the external connection terminals 15a and 15b.
[0034]
At this time, since the pressing portion 2a is formed on the top 1c of the reversing spring 1, a relative positional deviation from the top of the reversing spring 1 occurs due to a mounting error of the key top, an inclination at the time of pressing, and the like. Even if it does, the pressing force from the key top can be reliably applied to the reversing spring 1, and a good operation feeling can be obtained.
[0035]
FIG. 7 shows a sheet-like switch device in which a large number of the reversing springs 1 are mounted on a contact board on which fixed contacts are formed.
The contact substrate 30 as a base in the sheet-like switch device 40 is formed from a laminated plate of an insulating resin or the like, and a plurality of sets of fixed contacts 31 are formed on the surface thereof by copper foil, carbon, or the like. . The fixed contact 31 is provided with a central fixed contact 31a spaced apart from a peripheral fixed contact 31b formed in an annular shape, and each is connected to an external terminal by a connection pattern. The outer peripheral edge portion 1a of the reversing spring 1 is placed on the peripheral fixed contact 31b so as to be always conductive, and the contact portion 2b of the reversing spring 1 is disposed on the central fixed contact 31a so as to be able to contact and separate therefrom. A movable contact is formed.
[0036]
The reversing spring 1 is covered with an insulating flexible pressure-sensitive adhesive sheet 35 having a pressure-sensitive adhesive layer formed on the lower surface on the side where the pressing portion 2a is provided. Then, the sheet-like switch device 40 is formed by being adhered to the upper surface of the contact substrate 30 by the adhesive layer formed on the adhesive margin 35a of the adhesive sheet 35, and the intrusion of dust from the outside into the contact portion is prevented. ing.
[0037]
The sheet-like switch device 40 configured as described above is assembled into an electronic device by disposing a keytop on the upper surface of the flexible adhesive sheet 35, and at the time of this assembling, the keytop and the reversing spring 1 are positioned relative to each other. Even if the displacement occurs, the pressing force from the key top can be reliably applied to the reversing spring 1 via the pressing portion 2a, and a good operation feeling can be obtained.
In the above embodiment, the upper surface of the pressing portion 2a is also covered by the adhesive sheet 35. However, instead of this, an opening is formed in the adhesive sheet 35, and the pressing portion 2a is formed through the opening. May be formed so as to protrude from the upper surface of the adhesive sheet 35.
[0038]
According to the configuration of the embodiment of the present invention described above, the reversing spring 1 deforms the outer peripheral portion of the projecting member 2 so that the projecting member 2 sandwiches the spring member from both upper and lower surfaces in the thickness direction of the spring member. The depression 1c is retained in the hole 1d, and the depression 2c is formed in the center of the pressing part 2 so that the thickness of the outer peripheral part of the pressing part 2 is reduced by the thickness of the central part of the pressing part 2. Since the thickness is formed to be larger than the thickness, the spread of the flesh in the external direction at the time of caulking of the protruding member 2 can be increased, so that the fitting dimension of the caulked portion between the spring member and the protruding member 2 (bite amount). Can be increased, and when the pressing portion 2 is pressed by a key top or the like, the protrusion member 2 can be prevented from falling off.
[0039]
Further, the projecting member 2 is formed of a conductive metal material, and the other end of the pressing portion 2a is protruded toward the lower surface of the bulging portion of the spring member to form the contact portion 2b. Since the groove portion 2d is formed on the surface of the portion 2b, the contact portion 2b having a large number of contact points is formed around the groove portion 2d, so that the contact reliability with the central fixed contacts 16a and 31a is improved. A reversible spring that can be achieved is obtained.
[0040]
【The invention's effect】
As described above, the reversing spring of the present invention has a reversible swelling portion, a spring member having a through-hole formed at the top of the swelling portion, and a spring member inserted into the through-hole and one end of the spring member. A projection member protruding and held on an upper surface side in a plate thickness direction; and a pressing portion formed on the upper surface side of the projection member and transmitting a pressing force from the outside. The outer peripheral portion of the projecting member is deformed so as to be sandwiched from both upper and lower surfaces of the pressing portion, and the retaining member is retained in the through hole, and a thin concave portion is formed at the center of the pressing portion, and the thickness of the outer peripheral portion of the pressing portion is reduced. Since the pressing portion is formed to be thicker than the central portion, the spread of the flesh in the outer direction at the time of caulking of the protruding member can be increased, so that the caulked portion of the spring member and the protruding member is fitted. The size (bite-in amount) can be increased, and the protrusion It fell thus the can be prevented by, the reliability can be improved.
[0041]
Also, since the projecting member is formed of a conductive member, and the other end of the pressing portion is protruded to the lower surface of the bulging portion of the spring member to form a contact portion, and a groove is formed on the surface of the contact portion. Since a large number of projecting contact portions are formed around the groove, a reversing spring that can improve the contact reliability with the fixed contact can be obtained.
[0042]
Further, the method of manufacturing the reversing spring includes a step of inserting a projecting member made of a metal material thicker than the plate thickness into a through hole of a spring member made of a thin metal plate having a through hole formed in the plate thickness direction; A step in which the outer peripheral portion of the protruding member is bitten and held by the inner edge of the through hole of the spring member by pressing and deforming the protruding member between the lower die and the lower die; Forming a convex portion at the center of the contact surface with the upper mold projecting member. When the projecting member is deformed under pressure, the thickness of the projecting member on the upper surface side is reduced by the central portion. Since it is designed to be spread outward from the outer peripheral portion, the spread of the flesh in the outer shape direction at the time of caulking of the protruding member can be increased by a simple method of merely providing the convex portion on the upper mold for pressing, so that the spring member Dimensions of the swaged part between the ) Can be increased.
[0043]
In addition, a projection is formed on the contact surface with the lower projection member, and when the projection member is deformed under pressure, the thickness of the lower surface side of the projection member is pushed and widened toward the outer peripheral portion by the projection. A contact portion having a large number of contact points around the groove can be formed with high accuracy by a simple method of merely providing a projection on the lower die for pressurization.
[0044]
Further, the switch device includes the reversing spring according to the first or second means, a fixed contact, and a base provided with an external connection terminal that is electrically connected to the fixed contact. Since the pressing portion is arranged on the base so as to be operable from the outside while being opposed to the fixed contact, even if a relative displacement occurs between the key top and the reversing spring, the reversing spring swells. The pressing force of the keytop can be reliably transmitted to the top of the part, and a good operation feeling can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a reversing spring according to an embodiment of the present invention.
FIG. 2 is a partially detailed view showing a state before caulking of a projection member of the present invention.
FIG. 3 is a partial detailed view showing a relationship between a protrusion member and a mold at the time of caulking according to the present invention.
FIG. 4 is a partially detailed view showing a state after swaging of a projection member of the present invention.
FIG. 5 is a plan view showing a switch device on which the reversing spring of the present invention is mounted.
FIG. 6 is a sectional view showing a switch device on which the reversing spring of the present invention is mounted.
FIG. 7 is an exploded perspective view showing a state in which a part of another switch device on which the reversing spring of the present invention is mounted is broken.
[Explanation of symbols]
1 reverse spring (spring member)
1a Outer edge 1b Skirt 1c Top 1d Through hole 2 Projecting member 2a Pressing portion 2b Contact 2c Depression 2d Groove 10 Push button switch 11 Housing 11a Bottom plate 11b Side wall 12 Storage 13 Adhesive sheet 13a Pasting margin 15a, 15b External connection terminals 16 Fixed Contact 16a Central Fixed Contact 16b Peripheral Fixed Contact 30 Contact Board 31 Fixed Contact 31a Central Fixed Contact 31b Peripheral Fixed Contact 35 Flexible Adhesive Sheet 35a Paste 40 Sheet Switch Device J Upper Ja Convex K Lower Ka Protrusion Department
