JP4237327B2

JP4237327B2 - Torque switch

Info

Publication number: JP4237327B2
Application number: JP07982799A
Authority: JP
Inventors: 彪朽原
Original assignee: Seibu Electric and Machinery Co Ltd
Current assignee: Seibu Electric and Machinery Co Ltd
Priority date: 1999-03-24
Filing date: 1999-03-24
Publication date: 2009-03-11
Anticipated expiration: 2019-03-24
Also published as: JP2000274543A

Description

【０００１】
【発明の属する技術分野】
本発明は、弁操作装置において負荷トルク状態に応じて適切に動作切替を行うトルクスイッチに関する。
【０００２】
【従来の技術】
流体を給送する管路に配設される弁においては、開閉操作機構として手動機構の他、電動機を用いる遠隔操作機構が一般的となっている。こうした電動機を用いた弁操作機構では、従来から、全閉時に締切り状態を完全にするため、弁の閉位置において弁座面の力が増大し、操作部の駆動トルクが定められた値以上になった時に、トルクスイッチを動作させて電動機を停止させ、弁の閉止動作を停止させるトルクストップ（トルクシーティング）方式が採用されている。
【０００３】
こうした従来の弁操作機構に用いられているトルクスイッチの一例を図８ないし図１１に示す。この図８は従来のトルクスイッチを用いる弁操作装置の断面図、図９は従来のトルクスイッチを用いる弁操作装置の他の断面図、図１０は従来のトルクスイッチの正面図、図１１は従来のトルクスイッチの側面図を示す。
【０００４】
前記各図において従来のトルクスイッチ１１０を用いる弁操作装置１００は、管路中に配設される弁（図示を省略）と組合わせて用いられる装置であり、前記弁に隣接させて配設される装置ケース１０１と、この装置ケース１０１内に回動自在に配設される略筒状のスリーブ１０２と、このスリーブ１０２内に軸方向摺動可能に一部挿入されてスリーブ１０２と一体で回動可能に配設される略筒状体で形成され、前記弁の弁軸端部（図示を省略）を内側に螺合させてなるステムブッシュ１０３と、前記スリーブ１０２外周に回動自在に配設されるウォームホイール１０４と、このウォームホイール１０４の近傍の前記スリーブ１０２外周に軸方向摺動自在且つスリーブ１０２と一体に回動可能に配設され、スリーブ１０２上を移動して手回し用ハンドル１０８とスリーブ１０２との連動、又はウォームホイール１０４とスリーブ１０２との連動を切替え可能とするクラッチ１０５と、前記装置ケース１０１に回動自在に配設され、軸方向中間位置にウォームホイール１０４に噛合するウォーム１０６ａを形成されてなるウォーム軸１０６と、前記装置ケース１０１外側に配設されて前記ウォーム軸１０６を駆動する電動機１０７とを備える構成である。
【０００５】
前記ウォーム軸１０６は、前記装置ケース１０１に軸受１０１ａを介して回動自在に軸支されると共に軸方向に所定範囲移動自在とされてなり、ウォーム１０６ａに対し一端側には電動機１０７から駆動力を受ける歯車１０６ｂを配設されると共に、軸上の二箇所から鍔状に突出して間にトルクスイッチ１１０端部を係合させるトルク検出部１０６ｃを形成され、さらに、他端側にはウォームホイール１０４からの負荷トルクで軸全体が中立位置から軸方向にずれた場合にずれと反対方向の付勢力を与えるトルクスプリング１０６ｄを配設される構成である。
【０００６】
そして、従来のトルクスイッチ１１０は、前記弁操作装置１００の装置ケース１０１内部に支持固定されるスイッチベース１１１と、このスイッチベース１１１に前記ウォーム軸１０６と直交する向きで回動自在に軸支され、前記スイッチベース１１１への軸支部分に対して偏心した一端部を前記ウォーム軸１０６のトルク検出部１０６ｃに係合させてウォーム軸１０６の軸方向の動きに合わせて回動するクランク軸１１２と、このクランク軸１１２の他端側に略鍔状に形成され、クランク軸１１２を中心とする所定径位置に円弧状の長孔（図４（Ａ）参照；長孔１３ａ）を有する目盛板１１３と、この目盛板１１３の長孔に位置調整自在に配設されるスイッチ切替用螺子１１４と、前記クランク軸１１２に回動自在に取付けられ、ねじりばね１１５で所定回動方向に付勢されてなるスイッチ押圧レバー１１６と、前記スイッチベース１１１に取付けられる前記電動機１０７制御用のスイッチ１１７とを備える構成である。前記スイッチ押圧レバー１１６は、ねじりばね１１５により前記クランク軸１１２に対しスイッチ１１７に近付く向きに付勢され、他から拘束力を受けない限りスイッチ１１７の可動部１１７ａを押圧してスイッチ１１７の開閉いずれかの状態を保持する。
【０００７】
上記した従来のトルクスイッチの動作について説明する。弁を開放状態から閉止させた場合など、弁軸と一体に回動するウォームホイール１０４が回転できない状態になると、電動機１０７から駆動力を受けて回転を続けているウォーム軸１０６のウォーム１０６ａが負荷トルクの上昇でウォームホイール１０４に対しウォーム回転方向と逆向きの力を受け、ウォーム軸１０６全体がトルクスプリング１０６ｄによる付勢力を受けながら負荷トルクに応じた距離だけ軸方向に移動する。ウォーム軸１０６が軸方向に移動すると、ウォーム軸１０６に係合するトルクスイッチ１１０のクランク軸１１２及び目盛板１１３がスイッチベース１１１に対し回転し、ウォーム軸１０６の変位が回動変位に置換えられる。
【０００８】
あらかじめ作動限度として設定した負荷トルクに対応する軸方向位置までウォーム軸１０６が移動すると、クランク軸１１２もこの負荷トルクに対応した所定角度まで回転し、目盛板１１３に取付けられたスイッチ切替用螺子１１４がスイッチ押圧レバー１１６に接触してスイッチ押圧レバー１１６を押し、スイッチ押圧レバー１１６がスイッチ１１７の可動部１１７ａを解放し、スイッチ１１７の開閉状態が入れ替る。こうしてトルクスイッチ１１０のスイッチ１１７が作動することで電動機１０７の回動を適切に停止制御できる。
【０００９】
一方、閉止状態から弁を開放させる場合など、電動機を前記と逆向きに起動させる際には、電動機１０７を作動させてウォーム軸１０６を前記と逆向きの弁開放方向に回転させると、ウォーム軸１０６は駆動力を受けて前記と逆の軸方向に移動し、クランク軸１１２は移動に伴って回転し、ねじりばね１１５から付勢力を受けるスイッチ押圧レバー１１６は目盛板１１３及びスイッチ切替用螺子１１４の移動に伴ってスイッチ１１７側に移動し、スイッチ押圧レバー１１６がスイッチ１１７の可動部１１７ａを押圧し、スイッチ１１７を元の状態に復帰させる。そのままクランク軸１１２が回転すると、スイッチ１１７を押圧して停止したスイッチ押圧レバー１１６からスイッチ切替用螺子１１４が離れて移動する。このように、従来のトルクスイッチ１１０では、電動機１０７でウォーム軸１０６の回転駆動を行って弁を開閉し、最終的に弁が閉止位置又は開放の限界位置まで移動した場合に、スイッチ１１７を作動させて電動機１０７を確実に停止させられ、過負荷による悪影響を防げる。
【００１０】
また、弁においては、操作機構と弁軸が一体の場合、高温の流体を給送する管路で弁を温まった状態で閉じると、高温流体が流れ込まないことによる弁下流側の温度低下で弁軸の収縮が起り、弁体と弁座の密着力が低下してトラブルの原因になることがある。こうした現象を防ぐために、従来から、弁軸を弁閉鎖側に付勢する緩衝ばねを操作機構に内蔵し、温度低下による弁軸の収縮が起きても弁体を弁座に押付けて密着させる仕組みが使用されている。前記従来の弁操作装置１００においては、弁軸と一体のステムブッシュ１０２を弁閉止状態で常に弁閉止方向に付勢する緩衝ばね１０９を装置ケース１０１内に配設し、閉止状態で温度低下による弁軸の収縮が起きても緩衝ばね１０９による付勢でステムブッシュ１０２を介して弁軸に弁閉止方向の力を与え、弁体を弁座に押付けることができる。
【００１１】
【発明が解決しようとする課題】
従来のトルクスイッチは以上のように構成されていたが、前記した弁全閉後の弁軸収縮が生じて緩衝ばね１０９により弁軸が弁閉止側に若干移動すると、ウォームホイール１０４も弁閉止方向に少し回動してウォーム軸１０６の負荷トルクを減少させ、トルクスプリング１０６ｄの付勢力でウォーム軸１０６が中立側に多少戻ることから、トルクスイッチ１１０のクランク軸１１２がこの動きにそのまま反応し、スイッチ１１７を元の状態に復帰させることとなる。この時、電動機１０７が再び閉止方向へ回り出してしまうことに加え、弁操作をコンピュータ制御としている場合、弁閉止状態でも電動機１０７が作動しているということで異常と判断され、制御上問題があるという課題を有した。
【００１２】
本発明は前記課題を解消するためになされたもので、弁軸収縮に伴う負荷トルク減少で電動機が誤動作する等のトラブルを防ぎ、弁操作機構の信頼性を向上させる弁操作装置のトルクスイッチを提供することを目的とする。
【００１３】
【課題を解決するための手段】
本発明に係るトルクスイッチは、少なくとも負荷トルクに応じて軸方向へ所定量移動する回動軸を有する弁操作装置の装置ケースに固定されるスイッチベースと、当該スイッチベースに前記回動軸と直交する向きで回動自在に軸支される略軸状体で形成され、一端部が前記スイッチベースへの軸支部分に対して偏心して回転軸外周の一部に係合し、回転軸の軸方向変位を略軸状体の回動変位に変換するクランク軸と、当該クランク軸の他端部からクランク軸に対する径方向へ所定寸法延出させて配設されるスイッチ切替部と、前記クランク軸近傍に取付けられ、クランク軸に対する接線方向への変位により開閉状態を切替える可動部を有するスイッチと、前記クランク軸に所定角度回動自在且つ前記スイッチの可動部に接触可能に取付けられ、前記スイッチの可動部に接触する向きに付勢され、前記クランク軸の回動に伴って移動する前記スイッチ切替部の軌道上に一部が位置してスイッチ切替部に接触可能なスイッチ押圧レバーとを備え、前記弁操作装置の回動軸の所定負荷トルクに基づく軸方向移動に伴って前記クランク軸が所定角度回動すると、前記スイッチの可動部を付勢により押圧している前記スイッチ押圧レバーがクランク軸と共に移動した前記スイッチ切替部に押されて回動し、スイッチ押圧レバーがスイッチから離れる向きに移動してスイッチの可動部を押圧状態から解放し、スイッチの可動部が前記押圧方向と逆向きに動いてスイッチの開閉状態が切り替る仕組みであるトルクスイッチにおいて、前記スイッチ押圧レバーが前記スイッチの可動部を解放している状態で、前記クランク軸が前記回動方向と逆方向に所定角度回動するまでスイッチ押圧レバーをスイッチ側への付勢に抗して拘束し、スイッチを押圧しない状態を保つスイッチ保持手段を備え、当該スイッチ保持手段が、前記クランク軸と平行な軸を中心に回動自在に軸支され且つ回動に伴う回動中心から所定寸法離れた一端部の移動の軌道が前記スイッチ押圧レバーの前記スイッチに向う移動の軌道と略直交する所定の配置で前記スイッチベースに配設されてなり、前記スイッチ押圧レバーがスイッチの可動部を解放している状態で、所定の付勢力を与えられて回動し、前記一端部をスイッチ押圧レバーに接触係合させてスイッチ押圧レバーのスイッチ側への移動を拘束すると共に、前記クランク軸が前記逆方向に前記所定角度回動した状態で、付勢力の向きと逆方向に回動され、スイッチ押圧レバーから一端部を離してスイッチ押圧レバーの拘束を解くスイッチ保持レバーであるものである。
【００１４】
このように本発明においては、スイッチの可動部を解放した状態となったスイッチ押圧レバーを拘束するスイッチ保持手段を配設し、スイッチの可動部をスイッチ押圧レバーが押圧した状態からクランク軸が回動してスイッチの可動部をスイッチ押圧レバーが解放した状態となった後、クランク軸が逆方向に回動し、スイッチ切替部も元の方向に移動してスイッチ押圧レバーが付勢力でスイッチ側に移動可能となっても、クランク軸が所定角度まで回動するまではスイッチ保持手段がスイッチ押圧レバーをスイッチ側へ動かないよう保持することにより、スイッチをスイッチ押圧レバーが解放している状態で弁の弁軸収縮などの理由で負荷トルクが減少した場合でも、クランク軸の逆方向への回動角度が前記所定角度より小さいかぎり、スイッチ押圧レバーがスイッチ側に戻らずスイッチの状態が保持され、弁操作装置の状態が確実に維持されてトラブルの発生がなく、信頼性を向上させられる。
【００１６】
詳細には、スイッチ保持手段としてのスイッチ保持レバーをスイッチベースに回動自在に配設し、スイッチの可動部をスイッチ押圧レバーが押圧した状態からクランク軸が回動してスイッチの可動部をスイッチ押圧レバーが解放するとスイッチ保持レバーの一端部がスイッチ押圧レバーに所定の方向から接触係合してスイッチ押圧レバーを拘束し、また、スイッチの可動部をスイッチ押圧レバーが解放している状態からクランク軸が前記と逆方向に所定角度まで回動すると、スイッチ保持レバーの一端部がスイッチ押圧レバーから離れて拘束を解くことにより、スイッチ保持レバーがスイッチ押圧レバーに係合している間はスイッチ押圧レバーのスイッチ側へ向う付勢力をスイッチ保持レバーの一端部で受けてスイッチ押圧レバーを確実に保持でき、スイッチ押圧レバーからの力でスイッチ保持レバーが動かされることもなく、簡略な構造のスイッチ保持レバーでスイッチ押圧レバーの動作を適切に制御でき、信頼性を高められる。
【００１７】
また、本発明に係るトルクスイッチは必要に応じて、前記スイッチ切替部近傍で前記クランク軸と一体に配設される保持レバー解放体を備えると共に、前記スイッチ保持レバーが、前記一端部をスイッチ押圧レバーに接触係合させている状態で、前記保持レバー解放体のクランク軸回動に伴う移動の軌道上に少なくとも一部を位置させてなり、前記スイッチ押圧レバーが前記スイッチの可動部を解放している状態から前記クランク軸が前記逆方向に回動すると、前記保持レバー解放体が前記スイッチ保持レバーの一部に接触し、前記クランク軸が前記逆方向に前記所定角度回動した状態で保持レバー解放体が前記スイッチ保持レバーの一部を保持レバー解放体の軌道から外れる位置まで押しのけてスイッチ保持レバーを前記一端部がスイッチ押圧レバーから離れる位置まで回動させるものである。このように本発明においては、クランク軸と一体に保持レバー解放体を配設すると共に、スイッチ保持レバーの一部をスイッチ押圧レバーとスイッチ保持レバーの係合状態で保持レバー解放体の移動の軌道上に位置するよう形成し、クランク軸が前記逆方向に前記所定角度まで回動すると、保持レバー解放体が軌道上に位置するスイッチ保持レバーの一部を軌道外に押しのけることでスイッチ保持レバーを回動させ、スイッチ押圧レバーの拘束を解くことにより、保持レバー解放体を介してクランク軸の回動にそのまま対応させて直にスイッチ保持レバーを動かせることとなり、スイッチ保持レバーとスイッチ押圧レバーとの係合解除のタイミングをクランク軸の所定回転角度位置に合わせて適切にスイッチを復帰させられると共に、保持レバー解放体とスイッチ保持レバーからなる簡略な機構でスイッチ保持レバーとスイッチ押圧レバーとの係合解除を行えることとなり、部品点数を減らして低コスト化できる。
【００１８】
また、本発明に係るトルクスイッチは必要に応じて、前記保持レバー解放体が、クランク軸と平行をなす略円柱状のピンとして配設されると共に、前記スイッチ保持レバーが、前記保持レバー解放体の移動の軌道上に位置する部分として、前記クランク軸と平行な略円筒体のローラを回動自在に配設されてなり、前記保持レバー解放体の周側面が前記スイッチ保持レバーのローラの周側面に接触するものである。このように本発明においては、保持レバー解放体をピンとして配設する一方、スイッチ保持レバーに回動自在なローラを配設し、ローラとピンの周側面同士で接触を行わせることにより、ローラとピンとの接触が転がり接触となって摩擦等の抵抗が減り、スイッチ保持レバー及びクランク軸をよりスムーズに動かせ、トルクスイッチの動作抵抗を小さくできると共に、摺動による摩耗が減少して耐久性が向上する。さらに、ローラとピンとの接触でロスがなく、クランク軸の回動角度とスイッチ保持レバーの回動角度を一対一に対応させられ、スイッチ保持レバーとスイッチ押圧レバーとの係合解除のタイミングをクランク軸の所定回転角度位置に厳密に合わせることができ、スイッチの復帰動作を正確に同期させられる。
【００１９】
【発明の実施の形態】
以下、本発明の一実施の形態に係るトルクスイッチを図１〜図７に基づいて説明する。この図１は本実施の形態に係るトルクスイッチの正面図、図２は本実施の形態に係るトルクスイッチの一部省略正面図、図３は本実施の形態に係るトルクスイッチの側面図、図４（Ａ）は本実施の形態に係るトルクスイッチの平面図、図４（Ｂ）は図１のＡ−Ａ断面図、図５（Ａ）は本実施の形態に係るトルクスイッチにおけるスイッチ切替用螺子とスイッチ押圧レバーとの接触状態の平面図、図５（Ｂ）は本実施の形態に係るトルクスイッチにおけるスイッチ切替用螺子とスイッチ押圧レバーとの接触状態の要部概略説明図、図６（Ａ）は本実施の形態に係るトルクスイッチにおけるスイッチ切替わり状態の平面図、図６（Ｂ）は本実施の形態に係るトルクスイッチにおけるスイッチ切替わり状態の要部概略説明図、図７（Ａ）は本実施の形態に係るトルクスイッチにおけるスイッチ保持レバーとスイッチ押圧レバーとの係合解除途中の要部概略説明図、図７（Ｂ）は本実施の形態に係るトルクスイッチにおけるスイッチ保持レバーとスイッチ押圧レバーとの係合解除時点の要部概略説明図である。
【００２０】
前記各図に示すように、本実施の形態に係るトルクスイッチ１は、前記従来のトルクスイッチと同様、スイッチベース１１と、クランク軸１２と、前記スイッチ切替部としての目盛板１３及びスイッチ切替用螺子１４と、ねじりばね１５と、スイッチ押圧レバー１６と、スイッチ１７とを備える一方、異なる点として、前記目盛板１３の所定位置から前記クランク軸１２と平行に突出して目盛板１３と一体に形成される前記保持レバー解放体としての円筒形のピン１８と、前記スイッチベース１１に前記クランク軸１２と平行な軸中心で所定角度回動自在且つ前記スイッチ押圧レバー１６のスイッチ１７との接触側部分に接触係合可能に取付けられるスイッチ保持レバー１９とを備える構成を有するものである。なお、本実施の形態に係るトルクスイッチ１を用いる弁操作装置は前記従来の場合と同様のものであり、説明を省略する。
【００２１】
前記スイッチ保持レバー１９は、前記スイッチベース１１に前記クランク軸１２と平行な軸を中心に回動自在に支持され、回動中心から所定寸法離れた目盛板１３寄りの部分に前記クランク軸１２と平行に突出する回動自在な円筒状のローラ１９ａを有すると共に、スイッチ押圧レバー１６がスイッチ１５から離れた状態でスイッチ押圧レバー１６のスイッチ１７に面する側面に接触係合する前記一端部としての係合部１９ｂを形成されてなる構成であり、回動中心から所定寸法離れた前記係合部１９ｂの移動の軌道がスイッチ押圧レバー１６のスイッチ１７に向う移動の軌道と略直交するようにスイッチベース１１のクランク軸１２を挟んで二箇所に配設されている。二つのスイッチ保持レバー１９の間には係合部１９ｂをスイッチ押圧レバー１６に近付ける回動方向に各スイッチ保持レバー１９を付勢するばね１９ｃが配設される。また、前記ローラ１９ａは係合部１９ｂがスイッチ押圧レバー１６と係合している状態で前記ピン１８のクランク軸１２の回動に伴う移動の軌道上に位置するよう配置されている。
【００２２】
次に、前記構成に基づくトルクスイッチの動作について説明する。
弁を開放状態から閉止させた場合など、弁軸と一体に回動するウォームホイール１０４が回転できない状態になると、従来と同様、電動機１０７から駆動力を受ける前記回動軸としてのウォーム軸１０６が負荷トルクの上昇でウォームホイール１０４に対しウォーム回転方向と逆向きの力を受け、ウォーム軸１０６全体が負荷トルクに応じた距離だけ軸方向に移動する。ウォーム軸１０６の移動に伴い、トルクスイッチ１のクランク軸１２及び目盛板１３がスイッチベース１１に対し回転し、ウォーム軸１０６の変位が回動変位に置換えられる。
【００２３】
あらかじめ作動限度として設定した負荷トルクに対応する軸方向位置までウォーム軸１０６が移動すると、クランク軸１２もこの負荷トルクに対応した所定角度まで回転し、目盛板１３に取付けられたスイッチ切替用螺子１４がスイッチ押圧レバー１６に接触して（図５参照）スイッチ押圧レバー１６を押し、スイッチ押圧レバー１６がスイッチ１７の可動部１７ａを解放して、スイッチ１７の開閉状態が入れ替る（図６参照）。このスイッチ１７の作動で電動機１０７が停止する。このスイッチ押圧レバー１６がスイッチ１７の可動部１７ａを解放する際、スイッチ押圧レバー１６の移動でスイッチ保持レバー１９の係合部１９ｂとスイッチ押圧レバー１６側面との接触が外れることから、ばね１９ｃで付勢されているスイッチ保持レバー１９がスイッチ押圧レバー１６とスイッチ１７との間に係合部１９ｂを進入させ、スイッチ押圧レバー１６のスイッチ１７に面する側面に係合部１９ｂが接触した状態で係合する（図６参照）。こうしてスイッチ押圧レバー１６がスイッチ保持レバー１９によりスイッチ１７の可動部１７ａを解放した状態で拘束保持される。
【００２４】
一方、閉止状態から弁を開放させる場合など、電動機を前記と逆向きに起動させる際には、電動機１０７を作動させてウォーム軸１０６を前記と逆向きの弁開放方向に回転させると、ウォーム軸１０６は駆動力を受けて前記と逆の軸方向に移動し、クランク軸１２は移動に伴って回転する。この時、スイッチ保持レバー１９の先端部がスイッチ押圧レバー１６のスイッチ１７側の側面に接触してスイッチ押圧レバー１６を拘束していることから、スイッチ押圧レバー１６は目盛板１３及びスイッチ切替用螺子１４の移動に伴って動くことはなく、スイッチ１７側への移動もない。
【００２５】
電動機１０７によるウォーム軸１０６の駆動で負荷トルクが減少し、ウォーム軸１０６が中立位置に近付くと、クランク軸１２と共に回動する目盛板１３から突出しているピン１８が、このピン１８の軌道上に存在するスイッチ保持レバー１９のローラ１９ａに接触し、転がり接触しながらローラ１９ａを押しのけつつ移動する状態となり、スイッチ保持レバー１９がスイッチ押圧レバー１６から離れる方向に動く（図７（Ａ）参照）。スイッチ保持レバー１９がピン１８に押される形で付勢に抗して回転し、スイッチ保持レバー１９の係合部１９ｂがスイッチ押圧レバー１６のスイッチ１７側の側面から離れると（図７（Ｂ）参照）、スイッチ保持レバー１９の接触によるスイッチ押圧レバー１６の運動の拘束がなくなるため、ねじりばね１５から付勢力を受けるスイッチ押圧レバー１６はスイッチ１７へ向けて移動可能となり、スイッチ押圧レバー１６は移動してスイッチ１７の可動部１７ａを押圧し、スイッチ１７を元の状態に復帰させる（図４参照）。この後、クランク軸１２の回動に伴ってピン１８がスイッチ保持レバー１９のローラ１９ａから離れると、スイッチ保持レバー１９は付勢によってスイッチ押圧レバー１６側に回動し、スイッチ保持レバー１９の係合部１９ｂがスイッチ押圧レバー１６の側面に接触した状態となる。
【００２６】
これにより、弁閉止に際して前記したスイッチ１７の作動で電動機１０７が停止し、且つスイッチ押圧レバー１６がスイッチ保持レバー１９によりスイッチ１７から離れた状態で保持された状態で、温度低下等による弁軸収縮が生じて緩衝ばね１０９により弁軸が弁閉止側に若干移動し、これに伴うウォームホイール１０４の回動で負荷トルクの低下したウォーム軸１０６が多少動く事態が起っても、この場合のウォーム軸１０６の移動量は中立位置まで達することのないわずかなものであることから、トルクスイッチ１のクランク軸１２はウォーム軸１０６に対応して回転するものの、前記スイッチ保持レバー１９がスイッチ押圧レバー１６をスイッチ１５復帰側に回動しないよう確実に保持することとなり、スイッチ１７を元の状態に復帰させることもなく、電動機１０７が再び閉止方向へ回り出すのを防ぐことができる。
【００２７】
このように、本実施の形態に係るトルクスイッチでは、スイッチ押圧レバー１６を拘束するスイッチ保持レバー１９を配設し、設定された負荷トルクでスイッチ１７が作動して電動機１０７が停止するのと同時に、スイッチ保持レバー１９がスイッチ押圧レバー１６をスイッチ１７の可動部１７ａを解放した状態で保持すると共に、トルク減少時にはピン１８でスイッチ保持レバー１９を動かしてスイッチ押圧レバー１６の保持を解除することから、スイッチ押圧レバー１６のスイッチ１７に対する解放又は押圧のタイミングを負荷トルクの増大時と減少時とで異ならせることができ、弁軸収縮等によるトルク微減時にスイッチ押圧レバー１６を対応させないようにしてスイッチ１７の復帰を防ぐことができ、弁操作機構がコンピュータ制御の場合に誤って異常と判断される事態を減らして制御系の信頼性を大幅に高めることができる。
【００２８】
なお、前記実施の形態に係るトルクスイッチにおいては、保持レバー解放体としてのピン１８がスイッチ保持レバー１９のローラ１９ａと転がり接触しながらスイッチ保持レバー１９をスイッチ押圧レバー１６との係合解除方向に動かす構成としているが、これに限らず、スイッチ保持レバー１９側のピン１８との接触部位を固定接触子とし、ピン１８と摺動させつつスイッチ保持レバー１９を動かす構成とすることもできる。
【００２９】
また、前記実施の形態に係るトルクスイッチにおいては、スイッチ切替用螺子１４、スイッチ押圧レバー１６、スイッチ１７、ピン１８、及びスイッチ保持レバー１９をそれぞれクランク軸１２に対し対称に二つ配設し、弁操作装置のウォーム軸１０６の開方向と閉方向の回動それぞれについて所定の負荷トルクに対するスイッチ動作を行う構成としているが、この他、前記各部品を一つずつ配設し、ウォーム軸１０６の開方向又は閉方向のいずれか一方の回動について用いる構成としてもよい。
【００３０】
【発明の効果】
以上のように本発明によれば、スイッチの可動部を解放した状態となったスイッチ押圧レバーを拘束するスイッチ保持手段を配設し、スイッチの可動部をスイッチ押圧レバーが押圧した状態からクランク軸が回動してスイッチの可動部をスイッチ押圧レバーが解放した状態となった後、クランク軸が逆方向に回動し、スイッチ切替部も元の方向に移動してスイッチ押圧レバーが付勢力でスイッチ側に移動可能となっても、クランク軸が所定角度まで回動するまではスイッチ保持手段がスイッチ押圧レバーをスイッチ側へ動かないよう保持することにより、スイッチをスイッチ押圧レバーが解放している状態で弁の弁軸収縮などの理由で負荷トルクが減少した場合でも、クランク軸の逆方向への回動角度が前記所定角度より小さいかぎり、スイッチ押圧レバーがスイッチ側に戻らずスイッチの状態が保持され、弁操作装置の状態が確実に維持されてトラブルの発生がなく、信頼性を向上させられるという効果を奏する。
【００３１】
また、本発明によれば、スイッチ保持手段としてのスイッチ保持レバーをスイッチベースに回動自在に配設し、スイッチの可動部をスイッチ押圧レバーが押圧した状態からクランク軸が回動してスイッチの可動部をスイッチ押圧レバーが解放するとスイッチ保持レバーの一端部がスイッチ押圧レバーに所定の方向から接触係合してスイッチ押圧レバーを拘束し、また、スイッチの可動部をスイッチ押圧レバーが解放している状態からクランク軸が前記と逆方向に所定角度まで回動すると、スイッチ保持レバーの一端部がスイッチ押圧レバーから離れて拘束を解くことにより、スイッチ保持レバーがスイッチ押圧レバーに係合している間はスイッチ押圧レバーのスイッチ側へ向う付勢力をスイッチ保持レバーの一端部で受けてスイッチ押圧レバーを確実に保持でき、スイッチ押圧レバーからの力でスイッチ保持レバーが動かされることもなく、簡略な構造のスイッチ保持レバーでスイッチ押圧レバーの動作を適切に制御でき、信頼性を高められるという効果を有する。
【００３２】
また、本発明によれば、クランク軸と一体に保持レバー解放体を配設すると共に、スイッチ保持レバーの一部をスイッチ押圧レバーとスイッチ保持レバーの係合状態で保持レバー解放体の移動の軌道上に位置するよう形成し、クランク軸が前記逆方向に前記所定角度まで回動すると、保持レバー解放体が軌道上に位置するスイッチ保持レバーの一部を軌道外に押しのけることでスイッチ保持レバーを回動させ、スイッチ押圧レバーの拘束を解くことにより、保持レバー解放体を介してクランク軸の回動にそのまま対応させて直にスイッチ保持レバーを動かせることとなり、スイッチ保持レバーとスイッチ押圧レバーとの係合解除のタイミングをクランク軸の所定回転角度位置に合わせて適切にスイッチを復帰させられると共に、保持レバー解放体とスイッチ保持レバーからなる簡略な機構でスイッチ保持レバーとスイッチ押圧レバーとの係合解除を行えることとなり、部品点数を減らして低コスト化できるという効果を有する。
【００３３】
また、本発明によれば、保持レバー解放体をピンとして配設する一方、スイッチ保持レバーに回動自在なローラを配設し、ローラとピンの周側面同士で接触を行わせることにより、ローラとピンとの接触が転がり接触となって摩擦等の抵抗が減り、スイッチ保持レバー及びクランク軸をよりスムーズに動かせ、トルクスイッチの動作抵抗を小さくできると共に、摺動による摩耗が減少して耐久性が向上するという効果を有する。さらに、ローラとピンとの接触でロスがなく、クランク軸の回動角度とスイッチ保持レバーの回動角度を一対一に対応させられ、スイッチ保持レバーとスイッチ押圧レバーとの係合解除のタイミングをクランク軸の所定回転角度位置に厳密に合わせることができ、スイッチの復帰動作を正確に同期させられるという効果を有する。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係るトルクスイッチの正面図である。
【図２】本発明の一実施の形態に係るトルクスイッチの一部省略正面図である。
【図３】本発明の一実施の形態に係るトルクスイッチの側面図である。
【図４】本発明の一実施の形態に係るトルクスイッチの平面図及び図１のＡ−Ａ断面図である。
【図５】本発明の一実施の形態に係るトルクスイッチにおけるスイッチ切替用螺子とスイッチ押圧レバーとの接触状態の平面図及び要部概略説明図である。
【図６】本発明の一実施の形態に係るトルクスイッチにおけるスイッチ切替わり状態の平面図及び要部概略説明図である。
【図７】本発明の他の実施の形態に係るトルクスイッチにおけるスイッチ保持レバーとスイッチ押圧レバーとの係合解除途中及び係合解除時点の要部概略説明図である。
【図８】従来のトルクスイッチを用いる弁操作装置の断面図である。
【図９】従来のトルクスイッチを用いる弁操作装置の他の断面図である。
【図１０】従来のトルクスイッチの正面図である。
【図１１】従来のトルクスイッチの側面図である。
【符号の説明】
１、１１０トルクスイッチ
１１、１１１スイッチベース
１２、１１２クランク軸
１３、１１３目盛板
１３ａ長孔
１４、１１４スイッチ切替用螺子
１５、１１５ねじりばね
１６、１１６スイッチ押圧レバー
１７、１１７スイッチ
１７ａ、１１７ａ可動部
１８ピン
１９スイッチ保持レバー
１９ａローラ
１９ｂ係合部
１９ｃばね
１００弁操作装置
１０１装置ケース
１０１ａ軸受
１０２スリーブ
１０３ステムブッシュ
１０４ウォームホイール
１０５クラッチ
１０６ウォーム軸
１０６ａウォーム
１０６ｂ歯車
１０６ｃトルク検出部
１０６ｄトルクスプリング
１０７電動機
１０８手回し用ハンドル
１０９緩衝ばね[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a torque switch that appropriately switches operation according to a load torque state in a valve operating device.
[0002]
[Prior art]
In a valve disposed in a conduit for feeding fluid, a remote operation mechanism using an electric motor is generally used in addition to a manual mechanism as an opening / closing operation mechanism. Conventionally, in such a valve operating mechanism using an electric motor, in order to complete the shut-off state when fully closed, the force of the valve seat surface increases at the valve closed position, and the driving torque of the operating unit exceeds a predetermined value. When this happens, a torque stop (torque seating) system is employed in which the torque switch is operated to stop the motor and stop the valve closing operation.
[0003]
An example of a torque switch used in such a conventional valve operating mechanism is shown in FIGS. 8 is a cross-sectional view of a valve operating device using a conventional torque switch, FIG. 9 is another cross-sectional view of a valve operating device using a conventional torque switch, FIG. 10 is a front view of the conventional torque switch, and FIG. The side view of a torque switch is shown.
[0004]
In each of the drawings, a conventional valve operating device 100 using a torque switch 110 is a device used in combination with a valve (not shown) provided in a pipeline, and is provided adjacent to the valve. Device case 101, a substantially cylindrical sleeve 102 rotatably disposed in the device case 101, and a part of the sleeve 102 that is slidable in the axial direction is inserted into the sleeve 102 so as to rotate together with the sleeve 102. A stem bush 103 formed by a substantially cylindrical body that is movably disposed and having a valve shaft end portion (not shown) of the valve screwed inwardly, and rotatably disposed on the outer periphery of the sleeve 102. The worm wheel 104 provided and the outer periphery of the sleeve 102 in the vicinity of the worm wheel 104 are arranged so as to be slidable in the axial direction and rotatable integrally with the sleeve 102. A clutch 105 that can switch the interlocking between the handle 108 and the sleeve 102 or the interlocking between the worm wheel 104 and the sleeve 102, and the device case 101 are rotatably disposed, and the worm wheel 104 is positioned at an intermediate position in the axial direction. The configuration includes a worm shaft 106 formed with a meshing worm 106 a and an electric motor 107 that is disposed outside the apparatus case 101 and drives the worm shaft 106.
[0005]
The worm shaft 106 is rotatably supported on the device case 101 via a bearing 101a and is movable within a predetermined range in the axial direction. A driving force from an electric motor 107 is provided on one end side of the worm 106a. And a gear detecting portion 106c that protrudes from two locations on the shaft in a hook shape and engages the end portion of the torque switch 110 between them. A torque spring 106d is provided that applies an urging force in a direction opposite to the displacement when the entire shaft is displaced in the axial direction from the neutral position by the load torque from 104.
[0006]
The conventional torque switch 110 is rotatably supported in a direction perpendicular to the worm shaft 106 by a switch base 111 that is supported and fixed inside the device case 101 of the valve operating device 100. A crankshaft 112 that rotates with the movement of the worm shaft 106 in the axial direction by engaging one end portion that is eccentric with respect to the shaft support portion of the switch base 111 with the torque detection portion 106c of the worm shaft 106; The scale plate 113 is formed in a substantially bowl shape on the other end side of the crankshaft 112 and has an arc-shaped long hole (see FIG. 4A; long hole 13a) at a predetermined diameter position centered on the crankshaft 112. A switch-switching screw 114 that is disposed in the elongated hole of the scale plate 113 so as to be adjustable in position, and is rotatably attached to the crankshaft 112. A switch pressing lever 116 made is biased in a predetermined rotational direction at 115, is configured to include said electric motor 107 for controlling the switch 117 attached to the switch base 111. The switch pressing lever 116 is urged by the torsion spring 115 to approach the switch 117 with respect to the crankshaft 112, and presses the movable portion 117 a of the switch 117 as long as it receives no restraining force from the other, so that the switch 117 can be opened and closed. Hold the state.
[0007]
The operation of the conventional torque switch described above will be described. When the worm wheel 104 that rotates integrally with the valve shaft cannot be rotated, such as when the valve is closed from the open state, the worm 106a of the worm shaft 106 that continues to rotate by receiving the driving force from the electric motor 107 is loaded. As the torque rises, the worm wheel 104 receives a force opposite to the worm rotation direction, and the entire worm shaft 106 moves in the axial direction by a distance corresponding to the load torque while receiving the urging force of the torque spring 106d. When the worm shaft 106 moves in the axial direction, the crankshaft 112 and the scale plate 113 of the torque switch 110 engaged with the worm shaft 106 rotate with respect to the switch base 111, and the displacement of the worm shaft 106 is replaced with a rotational displacement.
[0008]
When the worm shaft 106 moves to the axial position corresponding to the load torque set as the operation limit in advance, the crankshaft 112 also rotates to a predetermined angle corresponding to this load torque, and the switch switching screw 114 attached to the scale plate 113. Contacts the switch pressing lever 116 and presses the switch pressing lever 116, the switch pressing lever 116 releases the movable portion 117a of the switch 117, and the open / close state of the switch 117 is switched. Thus, by operating the switch 117 of the torque switch 110, the rotation of the electric motor 107 can be appropriately stopped and controlled.
[0009]
On the other hand, when starting the electric motor in the opposite direction, such as when opening the valve from the closed state, when the electric motor 107 is operated to rotate the worm shaft 106 in the opposite valve opening direction, the worm shaft 106 receives the driving force and moves in the opposite axial direction, the crankshaft 112 rotates with the movement, and the switch pressing lever 116 receiving the urging force from the torsion spring 115 includes the scale plate 113 and the switch switching screw 114. Is moved to the switch 117 side, the switch pressing lever 116 presses the movable portion 117a of the switch 117, and the switch 117 is returned to the original state. When the crankshaft 112 rotates as it is, the switch switching screw 114 moves away from the switch pressing lever 116 that has stopped by pressing the switch 117. As described above, in the conventional torque switch 110, the worm shaft 106 is rotationally driven by the electric motor 107 to open and close the valve, and the switch 117 is operated when the valve finally moves to the closed position or the open limit position. Thus, the electric motor 107 can be surely stopped, and adverse effects due to overload can be prevented.
[0010]
In addition, in the valve, when the operation mechanism and the valve shaft are integrated, if the valve is closed in a heated state with a conduit that feeds a high-temperature fluid, the temperature is lowered on the downstream side of the valve because the high-temperature fluid does not flow. The shaft contracts, and the contact force between the valve body and the valve seat is reduced, which may cause trouble. In order to prevent such a phenomenon, a buffer spring that urges the valve shaft toward the valve closing side has been built into the operating mechanism, and the valve body is pressed against the valve seat even if the valve shaft contracts due to a temperature drop. Is used. In the conventional valve operating device 100, a buffer spring 109 that constantly urges the stem bush 102 integral with the valve shaft in the valve closing direction in the valve closed state is provided in the device case 101, and the temperature is lowered in the closed state. Even if the valve shaft contracts, a force in the valve closing direction can be applied to the valve shaft through the stem bush 102 by the urging force of the buffer spring 109 to press the valve body against the valve seat.
[0011]
[Problems to be solved by the invention]
The conventional torque switch is configured as described above. However, when the valve shaft contracts after the valve is fully closed as described above and the valve shaft is slightly moved to the valve closing side by the buffer spring 109, the worm wheel 104 also moves in the valve closing direction. To slightly reduce the load torque of the worm shaft 106 and the worm shaft 106 slightly returns to the neutral side by the urging force of the torque spring 106d, so that the crankshaft 112 of the torque switch 110 reacts to this movement as it is, The switch 117 is returned to the original state. At this time, in addition to the rotation of the electric motor 107 again in the closing direction, when the valve operation is computer controlled, it is determined that the electric motor 107 is operating even when the valve is closed, and there is a problem in control. I had the problem of being.
[0012]
The present invention has been made in order to solve the above-described problems, and provides a torque switch for a valve operating device that prevents troubles such as malfunction of an electric motor due to a decrease in load torque accompanying valve shaft contraction and improves the reliability of a valve operating mechanism. The purpose is to provide.
[0013]
[Means for Solving the Problems]
A torque switch according to the present invention includes a switch base that is fixed to a device case of a valve operating device that has a rotation shaft that moves in a predetermined amount in the axial direction according to at least load torque, and is orthogonal to the rotation shaft. And is formed of a substantially shaft-like body that is pivotally supported so as to be rotatable, and one end portion thereof is eccentric with respect to the shaft support portion to the switch base and engages with a part of the outer periphery of the rotation shaft. A crankshaft that converts a directional displacement into a rotational displacement of a substantially shaft-like body; a switch switching portion that is arranged to extend from the other end of the crankshaft in a radial direction with respect to the crankshaft; and the crankshaft A switch mounted in the vicinity and having a movable part that switches between open and closed states by displacement in a tangential direction with respect to the crankshaft, and mounted on the crankshaft so as to be rotatable by a predetermined angle and in contact with the movable part of the switch. A switch pressing lever that is biased in a direction to contact the movable part of the switch and that is partly located on a track of the switch switching part that moves with the rotation of the crankshaft and that can contact the switch switching part; The switch pressing lever that presses the movable part of the switch by urging when the crankshaft rotates by a predetermined angle along with the axial movement based on the predetermined load torque of the rotating shaft of the valve operating device Is pushed by the switch switching portion moved together with the crankshaft and rotated, and the switch pressing lever moves away from the switch to release the movable portion of the switch from the pressed state. In a torque switch that moves in the opposite direction and switches the open / closed state of the switch, the switch pressing lever releases the movable part of the switch. In state, a switch holding means for restraining against the switch pressing lever biased to the switch side, keeping the state of not pressing the switch to the crankshaft moving a predetermined angle in the rotational direction opposite to the direction The switch holding means is pivotally supported about an axis parallel to the crankshaft, and a trajectory of movement of one end portion separated from the rotation center by rotation by a predetermined dimension is the switch pressing lever. The switch base is arranged in a predetermined arrangement substantially perpendicular to the trajectory of the movement toward the switch, and is rotated with a predetermined urging force in a state where the switch pressing lever releases the movable part of the switch. The one end is contact-engaged with the switch pressing lever to restrain the switch pressing lever from moving toward the switch side, and the crankshaft is rotated in the opposite direction by the predetermined angle, A switch holding lever that is rotated in the opposite direction and releases one end from the switch pressing lever to release the restraint of the switch pressing lever. Is.
[0014]
As described above, in the present invention, the switch holding means for restraining the switch pressing lever in the state in which the movable part of the switch is released is disposed, and the crankshaft is rotated from the state where the switch pressing lever presses the movable part of the switch. After moving the switch and the switch pressing lever is released, the crankshaft rotates in the reverse direction, the switch switching unit moves in the original direction, and the switch pressing lever is biased by the switch side. The switch holding means holds the switch pressing lever so that it does not move to the switch side until the crankshaft rotates to a predetermined angle, so that the switch is released by the switch pressing lever. Even if the load torque decreases due to valve shaft contraction, etc., as long as the rotation angle of the crankshaft in the reverse direction is smaller than the predetermined angle, the switch Chi pressing lever is held state of the switch does not return to the switch side, there is no generation of trouble state of the valve operating device is reliably maintained, it is to improve the reliability.
[0016]
In detail A switch holding lever as a switch holding means is rotatably arranged on the switch base, and the crankshaft rotates from the state where the switch pressing lever presses the movable part of the switch, and the switch pressing lever releases the movable part of the switch. Then, one end of the switch holding lever contacts and engages the switch pressing lever from a predetermined direction to restrain the switch pressing lever, and the crankshaft is moved from the state where the switch pressing lever releases the movable part of the switch. When the switch holding lever is engaged with the switch pressing lever, the switch holding lever engages with the switch pressing lever by releasing one end of the switch holding lever away from the switch pressing lever. The switch pressing lever can be securely held by receiving an urging force toward the Without the switch holding lever is moved by the force from the pitch pressing lever, it can appropriately control the operation of the switch pressing lever switch holding lever simple structure, enhanced reliability.
[0017]
In addition, the torque switch according to the present invention includes a holding lever release body that is disposed integrally with the crankshaft in the vicinity of the switch switching portion, if necessary, and the switch holding lever presses the one end. In a state where the lever is in contact with the lever, at least a part of the holding lever releaser is positioned on a trajectory of movement associated with the rotation of the crankshaft, and the switch pressing lever releases the movable part of the switch. When the crankshaft is rotated in the opposite direction from the state in which the crankshaft is in the reverse direction, the holding lever release body contacts a part of the switch holding lever, and the crankshaft is held in the state rotated by the predetermined angle in the reverse direction. The lever release body pushes a part of the switch holding lever to a position where it is off the track of the holding lever release body, and the one end of the switch holding lever is switched It is intended to rotate to a position away from the pressure lever. As described above, in the present invention, the holding lever release body is disposed integrally with the crankshaft, and a part of the switch holding lever is moved in the engaged state of the switch pressing lever and the switch holding lever. When the crankshaft is rotated up to the predetermined angle in the opposite direction, the holding lever releaser pushes a part of the switch holding lever located on the track to move the switch holding lever out of the track. By rotating and releasing the restraint of the switch pressing lever, the switch holding lever can be moved directly corresponding to the rotation of the crankshaft via the holding lever releasing body, and the switch holding lever and the switch pressing lever The switch can be returned properly by matching the timing of disengagement with the predetermined rotational angle position of the crankshaft, and the holding level It will be able to disengagement between the switch holding lever and the switch pressing lever by a simple mechanism consisting of over release member and the switch holding lever can cost by reducing the number of parts.
[0018]
Further, in the torque switch according to the present invention, if necessary, the holding lever release body is disposed as a substantially cylindrical pin parallel to the crankshaft, and the switch holding lever is provided with the holding lever release body. A substantially cylindrical roller parallel to the crankshaft is rotatably disposed as a portion located on the trajectory of the movement, and a peripheral side surface of the holding lever releasing body is arranged around a periphery of the roller of the switch holding lever. It touches the side. As described above, in the present invention, the holding lever release body is provided as a pin, while the switch holding lever is provided with a rotatable roller so that the peripheral side surfaces of the roller and the pin are brought into contact with each other. The contact between the pin and the pin is a rolling contact, reducing the resistance of friction, etc., allowing the switch holding lever and crankshaft to move more smoothly, reducing the operating resistance of the torque switch, and reducing wear due to sliding, resulting in improved durability. improves. In addition, there is no loss due to contact between the roller and the pin, and the rotation angle of the crankshaft and the rotation angle of the switch holding lever can be made to correspond one-to-one. It can be precisely matched to the predetermined rotational angle position of the shaft, and the return operation of the switch can be accurately synchronized.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a torque switch according to an embodiment of the present invention will be described with reference to FIGS. 1 is a front view of a torque switch according to the present embodiment, FIG. 2 is a partially omitted front view of the torque switch according to the present embodiment, and FIG. 3 is a side view of the torque switch according to the present embodiment. 4 (A) is a plan view of the torque switch according to the present embodiment, FIG. 4 (B) is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 5 (A) is for switch switching in the torque switch according to the present embodiment. FIG. 5B is a schematic explanatory view of the main part of the contact state between the switch switching screw and the switch pressing lever in the torque switch according to the present embodiment, and FIG. FIG. 6A is a plan view of a switch switching state in the torque switch according to the present embodiment. FIG. 6B is a schematic explanatory diagram of a main part of the switch switching state in the torque switch according to the present embodiment. ) FIG. 7B is a schematic explanatory view of a main part in the middle of disengagement between the switch holding lever and the switch pressing lever in the torque switch according to the state, and FIG. 7B is a diagram of the switch holding lever and the switch pressing lever in the torque switch according to the present embodiment. It is a principal part schematic explanatory drawing at the time of engagement cancellation | release.
[0020]
As shown in the drawings, the torque switch 1 according to the present embodiment is similar to the conventional torque switch in that the switch base 11, the crankshaft 12, the scale plate 13 as the switch switching unit, and the switch switching switch. A screw 14, a torsion spring 15, a switch pressing lever 16, and a switch 17 are provided. On the other hand, the screw plate 14 protrudes in parallel with the crankshaft 12 from a predetermined position of the scale plate 13 and is integrally formed with the scale plate 13. A cylindrical pin 18 as the holding lever release body, and a portion of the switch base 11 that is rotatable at a predetermined angle about an axis parallel to the crankshaft 12 and that contacts the switch 17 of the switch pressing lever 16 And a switch holding lever 19 that is attached so as to be capable of contact engagement with the switch. The valve operating device using the torque switch 1 according to the present embodiment is the same as that in the conventional case, and the description thereof is omitted.
[0021]
The switch holding lever 19 is supported by the switch base 11 so as to be rotatable about an axis parallel to the crankshaft 12, and the crankshaft 12 The switch has a cylindrical roller 19a that protrudes in parallel and is rotatable, and the switch pressing lever 16 is in contact with the side face of the switch pressing lever 16 facing the switch 17 in a state of being separated from the switch 15. The engagement portion 19b is formed, and the switch is arranged so that the trajectory of movement of the engagement portion 19b away from the center of rotation by a predetermined dimension is substantially perpendicular to the trajectory of movement toward the switch 17 of the switch pressing lever 16. The base 11 is disposed at two locations across the crankshaft 12. Between the two switch holding levers 19, springs 19 c that urge the switch holding levers 19 in the rotational direction that brings the engaging portions 19 b closer to the switch pressing levers 16 are disposed. The roller 19a is disposed so as to be positioned on the trajectory of the movement of the pin 18 with the rotation of the crankshaft 12 in a state where the engaging portion 19b is engaged with the switch pressing lever 16.
[0022]
Next, the operation of the torque switch based on the above configuration will be described.
When the worm wheel 104 that rotates integrally with the valve shaft cannot be rotated, such as when the valve is closed from the open state, the worm shaft 106 as the rotating shaft that receives the driving force from the electric motor 107 is the same as in the past. As the load torque rises, the worm wheel 104 receives a force opposite to the worm rotation direction, and the entire worm shaft 106 moves in the axial direction by a distance corresponding to the load torque. As the worm shaft 106 moves, the crankshaft 12 and the scale plate 13 of the torque switch 1 rotate with respect to the switch base 11, and the displacement of the worm shaft 106 is replaced with a rotational displacement.
[0023]
When the worm shaft 106 moves to the axial position corresponding to the load torque set as the operation limit in advance, the crankshaft 12 also rotates to a predetermined angle corresponding to this load torque, and the switch switching screw 14 attached to the scale plate 13. Contacts the switch pressing lever 16 (see FIG. 5), presses the switch pressing lever 16, the switch pressing lever 16 releases the movable portion 17a of the switch 17, and the open / close state of the switch 17 is switched (see FIG. 6). . The electric motor 107 is stopped by the operation of the switch 17. When the switch pressing lever 16 releases the movable portion 17a of the switch 17, the contact between the engaging portion 19b of the switch holding lever 19 and the side surface of the switch pressing lever 16 is released by the movement of the switch pressing lever 16, so that the spring 19c The biased switch holding lever 19 causes the engaging portion 19b to enter between the switch pressing lever 16 and the switch 17, and the engaging portion 19b is in contact with the side surface of the switch pressing lever 16 facing the switch 17. Engage (see FIG. 6). Thus, the switch pressing lever 16 is restrained and held by the switch holding lever 19 with the movable portion 17a of the switch 17 released.
[0024]
On the other hand, when starting the electric motor in the opposite direction, such as when opening the valve from the closed state, when the electric motor 107 is operated to rotate the worm shaft 106 in the opposite valve opening direction, the worm shaft 106 receives a driving force and moves in the opposite axial direction, and the crankshaft 12 rotates with the movement. At this time, since the tip of the switch holding lever 19 contacts the switch 17 side surface of the switch pressing lever 16 to restrain the switch pressing lever 16, the switch pressing lever 16 has the scale plate 13 and the switch switching screw. It does not move with the movement of 14 and does not move to the switch 17 side.
[0025]
When the load torque is reduced by driving the worm shaft 106 by the electric motor 107 and the worm shaft 106 approaches the neutral position, the pin 18 protruding from the scale plate 13 that rotates together with the crankshaft 12 is on the track of the pin 18. The roller 19a of the existing switch holding lever 19 comes into contact with the roller 19a and moves while pushing the roller 19a while rolling, and the switch holding lever 19 moves away from the switch pressing lever 16 (see FIG. 7A). When the switch holding lever 19 rotates against the urging force by being pushed by the pin 18, and the engaging portion 19b of the switch holding lever 19 is separated from the side surface of the switch pressing lever 16 on the switch 17 side (FIG. 7B). Since the movement of the switch pressing lever 16 due to the contact of the switch holding lever 19 is no longer restricted, the switch pressing lever 16 that receives the biasing force from the torsion spring 15 can move toward the switch 17, and the switch pressing lever 16 moves. Then, the movable portion 17a of the switch 17 is pressed to return the switch 17 to the original state (see FIG. 4). Thereafter, when the pin 18 is separated from the roller 19a of the switch holding lever 19 with the rotation of the crankshaft 12, the switch holding lever 19 is rotated to the switch pressing lever 16 side by urging, and the engagement of the switch holding lever 19 is increased. The joint portion 19b comes into contact with the side surface of the switch pressing lever 16.
[0026]
Accordingly, when the valve is closed, the motor 107 is stopped by the operation of the switch 17 described above, and the valve shaft contracts due to a temperature drop or the like while the switch pressing lever 16 is held away from the switch 17 by the switch holding lever 19. Even if a situation occurs in which the valve shaft is slightly moved to the valve closing side by the buffer spring 109 and the worm shaft 106 having a reduced load torque is moved by the rotation of the worm wheel 104 due to this, the worm in this case Since the movement amount of the shaft 106 is a slight amount that does not reach the neutral position, the crankshaft 12 of the torque switch 1 rotates corresponding to the worm shaft 106, but the switch holding lever 19 is operated by the switch pressing lever 16. Is securely held so as not to rotate toward the return side of the switch 15, and the switch 17 is restored to the original state. Without thereby, the motor 107 can be prevented from out around again to the closing direction.
[0027]
As described above, in the torque switch according to the present embodiment, the switch holding lever 19 that restrains the switch pressing lever 16 is disposed, and at the same time when the switch 17 is operated with the set load torque and the electric motor 107 is stopped. The switch holding lever 19 holds the switch pressing lever 16 with the movable portion 17a of the switch 17 released, and when the torque decreases, the switch holding lever 19 is moved by the pin 18 to release the holding of the switch pressing lever 16. The timing of releasing or pressing the switch pressing lever 16 with respect to the switch 17 can be made different between when the load torque is increased and when the load torque is increased, and the switch pressing lever 16 is not made to correspond when the torque slightly decreases due to valve shaft contraction or the like. 17 can be prevented, the valve operating mechanism is computer controlled Can greatly increase the reliability of the control system to reduce the situation in which it is determined that an abnormality by mistake when.
[0028]
In the torque switch according to the above-described embodiment, the pin 18 serving as the holding lever releaser rolls into contact with the roller 19a of the switch holding lever 19 and moves the switch holding lever 19 in the direction in which the switch pressing lever 16 is disengaged. However, the present invention is not limited to this, and the contact portion with the pin 18 on the switch holding lever 19 side may be a fixed contact, and the switch holding lever 19 may be moved while sliding with the pin 18.
[0029]
Further, in the torque switch according to the embodiment, two switch switching screws 14, a switch pressing lever 16, a switch 17, a pin 18, and a switch holding lever 19 are arranged symmetrically with respect to the crankshaft 12, respectively. A switch operation is performed for a predetermined load torque for each of the opening and closing directions of the worm shaft 106 of the valve operating device. It is good also as a structure used about any one rotation of an opening direction or a closing direction.
[0030]
【The invention's effect】
As described above, according to the present invention, the switch holding means for restraining the switch pressing lever that is in a state in which the movable part of the switch is released is disposed, and the crankshaft is moved from the state in which the switch pressing lever presses the movable part of the switch. Turns and the switch pressing lever releases the movable part of the switch, then the crankshaft rotates in the reverse direction, the switch switching part also moves in the original direction, and the switch pressing lever is biased. Even if it can move to the switch side, the switch pressing lever releases the switch by holding the switch pressing lever so that the switch pressing lever does not move to the switch side until the crankshaft rotates to a predetermined angle. Even if the load torque is reduced due to the valve shaft contraction in the state, as long as the rotation angle of the crankshaft in the reverse direction is smaller than the predetermined angle, the switch Chi pressing lever is held state of the switch does not return to the switch side, there is no generation of trouble state of the valve operating device is reliably maintained, an effect that is to improve the reliability.
[0031]
Further, according to the present invention, the switch holding lever as the switch holding means is rotatably disposed on the switch base, and the crankshaft is rotated from the state in which the switch pressing lever presses the movable portion of the switch, so that the switch When the switch pressing lever is released from the movable part, one end of the switch holding lever contacts and engages the switch pressing lever from a predetermined direction to restrain the switch pressing lever, and the switch pressing lever releases the movable part of the switch. When the crankshaft is rotated to a predetermined angle in the opposite direction from the above state, the switch holding lever is engaged with the switch pressing lever by releasing one end of the switch holding lever away from the switch pressing lever. During this time, the switch pressing lever receives the biasing force toward the switch side of the switch pressing lever at one end of the switch holding lever. The switch holding lever is not moved by the force from the switch pressing lever, and the operation of the switch pressing lever can be appropriately controlled by the switch holding lever with a simple structure, improving the reliability. Have.
[0032]
Further, according to the present invention, the holding lever releaser is disposed integrally with the crankshaft, and a part of the switch holding lever is moved with the switch pressing lever and the switch holding lever engaged. When the crankshaft is rotated up to the predetermined angle in the opposite direction, the holding lever releaser pushes a part of the switch holding lever located on the track to move the switch holding lever out of the track. By rotating and releasing the restraint of the switch pressing lever, the switch holding lever can be moved directly corresponding to the rotation of the crankshaft via the holding lever releasing body, and the switch holding lever and the switch pressing lever The switch can be returned properly by adjusting the disengagement timing to the predetermined rotation angle position of the crankshaft, and the release of the holding lever Will be by a simple mechanism consisting of a body and the switch holding lever allows the disengagement of the switch hold lever and the switch pressing lever, has an effect of cost reduction by reducing the number of parts.
[0033]
Further, according to the present invention, the holding lever releaser is provided as a pin, while the switch holding lever is provided with a rotatable roller so that the peripheral side surfaces of the roller and the pin are brought into contact with each other. The contact between the pin and the pin is a rolling contact, reducing the resistance of friction, etc., allowing the switch holding lever and crankshaft to move more smoothly, reducing the operating resistance of the torque switch, and reducing wear due to sliding, resulting in improved durability. It has the effect of improving. In addition, there is no loss due to contact between the roller and the pin, and the rotation angle of the crankshaft and the rotation angle of the switch holding lever can be made to correspond one-to-one. It is possible to exactly match the predetermined rotational angle position of the shaft, and it is possible to accurately synchronize the return operation of the switch.
[Brief description of the drawings]
FIG. 1 is a front view of a torque switch according to an embodiment of the present invention.
FIG. 2 is a partially omitted front view of the torque switch according to the embodiment of the present invention.
FIG. 3 is a side view of a torque switch according to an embodiment of the present invention.
4 is a plan view of a torque switch according to an embodiment of the present invention and a cross-sectional view taken along line AA in FIG.
5A is a plan view of a contact state between a switch switching screw and a switch pressing lever in the torque switch according to the embodiment of the present invention, and FIG.
FIGS. 6A and 6B are a plan view and a main part schematic explanatory view of a switch switching state in the torque switch according to the embodiment of the present invention. FIGS.
FIG. 7 is a schematic explanatory view of a main part during and after the disengagement between the switch holding lever and the switch pressing lever in the torque switch according to another embodiment of the present invention.
FIG. 8 is a cross-sectional view of a conventional valve operating device using a torque switch.
FIG. 9 is another cross-sectional view of a conventional valve operating device using a torque switch.
FIG. 10 is a front view of a conventional torque switch.
FIG. 11 is a side view of a conventional torque switch.
[Explanation of symbols]
1,110 Torque switch
11, 111 switch base
12, 112 Crankshaft
13, 113 Scale plate
13a long hole
14, 114 Switch switching screw
15, 115 Torsion spring
16, 116 Switch pressing lever
17, 117 switch
17a, 117a Movable part
18 pin
19 Switch holding lever
19a Laura
19b Engagement part
19c spring
100 Valve operating device
101 Device case
101a Bearing
102 sleeve
103 stem bush
104 Worm wheel
105 clutch
106 Worm shaft
106a warm
106b gear
106c Torque detection unit
106d Torque spring
107 electric motor
108 Handwheel
109 Buffer spring

Claims

A switch base fixed to a device case of a valve operating device having a rotation shaft that moves in a predetermined amount in the axial direction according to at least a load torque, and a shaft that can rotate freely in a direction orthogonal to the rotation shaft. It is formed of a substantially shaft-like body to be supported, and one end portion thereof is eccentric with respect to the shaft-supporting portion to the switch base and engages with a part of the outer periphery of the rotation shaft. A crankshaft that converts to a rotational displacement, a switch switching portion that is arranged to extend from the other end of the crankshaft in a radial direction with respect to the crankshaft, and that is attached near the crankshaft and attached to the crankshaft. A switch having a movable part that switches an open / close state by displacement in a tangential direction, and a switch that is rotatable to a predetermined angle on the crankshaft and that can contact the movable part of the switch, and contacts the movable part of the switch A switch pressing lever that is biased in the direction and moves along with the rotation of the crankshaft and is partly located on a track of the switch switching unit and is capable of contacting the switch switching unit. The switch in which the switch pressing lever that presses the movable portion of the switch by urging is moved together with the crankshaft when the crankshaft is rotated by a predetermined angle along with the axial movement based on the predetermined load torque of the rotating shaft. When the switch is pushed by the switch and rotates, the switch pressing lever moves away from the switch to release the movable part of the switch from the pressed state, and the switch movable part moves in the direction opposite to the pressing direction to open and close the switch. In the torque switch, which is a mechanism for switching the state,
In a state where the switch pressing lever releases the movable part of the switch, the switch pressing lever is resisted against urging to the switch side until the crankshaft rotates a predetermined angle in the direction opposite to the rotating direction. It is provided with a switch holding means that restrains and keeps the switch from being pressed ,
The switch holding means is pivotally supported about an axis parallel to the crankshaft, and a trajectory of movement of one end that is separated from the center of rotation accompanying the rotation by a predetermined dimension is the switch of the switch pressing lever. It is arranged on the switch base in a predetermined arrangement substantially perpendicular to the trajectory of movement toward the switch, and rotates with a predetermined urging force in a state where the switch pressing lever releases the movable part of the switch. The one end is contacted and engaged with the switch pressing lever to restrain the movement of the switch pressing lever to the switch side, and the direction of the urging force with the crankshaft rotated by the predetermined angle in the opposite direction. A torque switch characterized by being a switch holding lever that is rotated in the opposite direction and releases one end from the switch pressing lever to release the restraint of the switch pressing lever .

The torque switch according to claim 1, wherein
A holding lever release body disposed integrally with the crankshaft in the vicinity of the switch switching portion;
The switch holding lever is positioned at least partially on the trajectory of movement of the holding lever releaser as the crankshaft rotates, with the one end being in contact with the switch pressing lever.
When the crankshaft rotates in the reverse direction from the state in which the switch pressing lever releases the movable part of the switch, the holding lever release body contacts a part of the switch holding lever, and the crankshaft The holding lever releaser pushes a part of the switch holding lever to a position where it deviates from the track of the holding lever releaser with the predetermined angle rotated in the reverse direction, and the one end of the switch holding lever moves away from the switch pressing lever. Torque switch characterized by rotating to a position .

The torque switch according to claim 2, wherein
The holding lever release body is disposed as a substantially cylindrical pin parallel to the crankshaft,
The switch holding lever is disposed so as to be rotatable in a substantially cylindrical roller parallel to the crankshaft as a portion located on the movement path of the holding lever release body,
The torque switch according to claim 1, wherein a peripheral side surface of the holding lever release body contacts a peripheral side surface of a roller of the switch holding lever .