JP3945129B2 - Power-driven rotary tool - Google Patents

Description

【００３７】
そして、シャットオフ判定部１０では、負荷変動量評価部１１の算出した負荷変動量ｄＴが所定のしきい値（以下、第３の閾値と言う。）以上になると、第１のシャットオフ指令をモータ制御部１２に出力すると共に、負荷トルクの推定値が第２の閾値に達すると第２のシャットオフ指令をモータ制御部１２に出力する。
【００３８】
ここで、シャットオフ判定処理について図５のフローチャートを参照して説明する。尚、モータ１の制御動作は基本構成と同様であるので、その説明は省略する。
【００３９】
打撃機構による打撃が発生すると、負荷トルク推定部８は打撃間のモータ１の回転数や打撃時のモータ１の回転速度からドライバビット６にかかる負荷トルクを推定し、シャットオフ判定部１０及び負荷変動量評価部１１に出力する（図５のＳ３１）。負荷変動量評価部１１は負荷トルク推定部８の推定値から負荷トルクの負荷変動量ｄＴを求め、シャットオフ判定部１０に出力する。シャットオフ判定部１０では、既に第３の閾値による第１のシャットオフ指令を出力したか否かを判断し（図５のＳ３２）、第１のシャットオフ指令を出力していなければ、負荷変動量評価部１１の求めた負荷変動量ｄＴと第３の閾値との高低を比較する（図５のＳ３３）。そして、負荷変動量ｄＴが第３の閾値以上であれば第１のシャットオフ指令をモータ制御部１２に出力する（図５のＳ３５）。一方、既に第１のシャットオフ指令を出力しているか、又は、負荷変動量ｄＴが第３の閾値未満であれば、シャットオフ判定部１０は推定トルクと第２の閾値との高低を比較し（図５のＳ３４）、推定トルクが第２の閾値に達すると第２のシャットオフ指令をモータ制御部１２に出力する（図５のＳ３６）。
【００４０】
ところで、上述したソフトジョイント部材のねじ締め作業を行う場合、着座直後にねじ締め作業を終了すれば、締付トルクが適正値となるので、本実施形態では負荷トルクの急激な上昇からねじ部材の着座を検出して、ねじ締め作業を終了させることにより、適切な締付トルクでソフトジョイント部材のねじ締め作業を行えるようにしている。すなわち本実施形態では、負荷変動量評価部１１の求めた負荷トルクの負荷変動量ｄＴが第３の閾値以上になると、シャットオフ判定部１０が第１のシャットオフ指令をモータ制御部１２に出力し、モータ制御部１２がモータ１の回転を停止させているので、ソフトジョイント部材のねじ込み作業を行っている場合は、モータ１の回転が最初に停止した時点でトリガスイッチ７を開放することにより、ソフトジョイント部材が着座した直後にねじ締め作業を終了させることができ、ソフトジョイント部材を適切な締付トルクで締め付けることができる。一方、ハードジョイント部材のねじ込み作業を行っている場合は、モータ１が最初に停止した後もトリガスイッチ７を引き続けていれば、モータ１の停止時から所定の停止時間が経過した時点でモータ制御部１２がモータ１を再び回転させ、負荷トルクが第２の閾値に達した時点でシャットオフ判定部が第２のシャットオフ指令をモータ制御部１２に出力し、モータ１を停止させているから、適正な締付トルクでハードジョイント部材のねじ締め作業を行うことができる。
【００４１】
尚、モータ制御部１２がモータ１の回転を一旦停止させる停止時間としては、負荷トルクの変動量が第３の閾値以上になった時点でねじ締め作業を終了したい場合に作業者がトリガスイッチ７を離すだけの時間を確保できるような時間であり、且つ、負荷トルクが第２のねじ部材の適正締付トルクに達した時点でねじ締め作業を完了させたい場合に、モータ１が再起動されるまでの待ち時間を長く感じることがないような時間に設定するのが望ましく、本実施形態では例えば略０．４５秒に設定している。尚、停止時間を０．４５秒に限定する趣旨のものではなく、上記の条件を満たすような時間に適宜設定すれば良く、例えば約０．２秒以上且つ約１秒以下の時間に設定するのが好ましい。
【００４２】
本実施形態ではソフトジョイント部材とハードジョイント部材の２種類のねじ部材の締付作業を行う場合を例にして説明したが、基本構成で説明したようにシャットオフ判定部１０に、複数のハードジョイント部材の適正締付トルクの値を設定して、負荷トルクの推定値が各適正締付トルクに達すると、シャットオフ判定部１０がシャットオフ指令をモータ制御部１２に出力するようにし、ソフトジョイント部材と、適正締付トルクの異なる複数のハードジョイント部材との締付作業を行うようにしても良いことは勿論のことである。
【００４３】
（実施形態２）
本発明の実施形態２を図６を参照して説明する。本実施形態では、実施形態１の動力駆動回転工具において、シャットオフ判定部１０から第３の閾値によるシャットオフ指令がモータ制御部１２に入力され、モータ制御部１２がシャットオフ指令によりモータ１を一時的に停止させてからモータ１を再起動するまでの停止時間（再起動待機時間）の設定値を変化させる再起動待機時間設定部（停止時間設定部）１５を設けている。尚、再起動待機時間設定部１５以外の構成は実施形態１と同様であるので、同一の構成要素には同一の符号を付して、その説明を省略する。
【００４４】
ここで、再起動待機時間設定部１５は例えばダイヤル式の操作摘みを備えており、この操作摘みを回転させることによって停止時間を例えば約０．２秒以上、約１秒以下の範囲、好ましくは約０．２５秒以上、約１秒以下の範囲で変化させることができる。上述のように停止時間は、負荷トルクの変動量が第３の閾値以上になった時点でねじ締め作業を終了したい場合に作業者がトリガスイッチ７を離すだけの時間を確保できるような時間であり、且つ、負荷トルクが第２のねじ部材の適正締付トルクに達した時点でねじ締め作業を完了させたい場合に、モータ１が再起動されるまでの待ち時間を長く感じることのないような時間に設定するのが望ましいが、この停止時間の設定を再起動待機時間設定部１５により変化させることができるので、作業者の習熟度に応じて停止時間を必要最小限の時間に設定することにより、作業時間を短縮することができる。
【００４５】
尚、本実施形態では実施形態１の動力駆動回転工具において停止時間の設定値を変化させるための再起動待機時間設定部１５を設けているが、基本構成で説明した動力駆動回転工具に本実施形態の再起動待機時間設定部１５を設けても良く、上述と同様の効果が得られる。
【００４６】
（実施形態３）
本発明の実施形態３を図７を参照して説明する。尚、動力駆動回転工具の構成は実施形態１と同様であるので、その説明は省略し、異なる部分についてのみ説明を行う。
【００４７】
シャットオフ判定部１０は、実施形態１と同様、負荷変動量評価部１１の算出した負荷変動量ｄＴが第３の閾値以上になると、第１のシャットオフ指令をモータ制御部１２に出力すると共に、負荷トルクの推定値が第２の閾値に達すると第２のシャットオフ指令をモータ制御部１２に出力する。またシャットオフ判定部１０では、負荷変動量評価部１１の求めた負荷トルクの変動量ｄＴが第３の閾値以上になっていない状態（すなわち第１のシャットオフ指令を出力していない状態）で、負荷トルク推定部８の推定した負荷トルクの推定値が第２の閾値に達して、第２のシャットオフ指令を出力した場合、モータ１の回転を作業者が認識できる程度の十分短い間だけモータ１を回転させた後停止させる第３のシャットオフ指令をモータ制御部１２に出力する。
【００４８】
ここで、シャットオフ判定処理について図７のフローチャートを参照して説明する。打撃機構による打撃が発生すると、負荷トルク推定部８は打撃間のモータ１の回転数や打撃時のモータ１の回転速度からドライバビット６にかかる負荷トルクを推定し、シャットオフ判定部１０及び負荷変動量評価部１１に出力する（図７のＳ４１）。負荷変動量評価部１１は負荷トルク推定部８の推定値から負荷トルクの負荷変動量ｄＴを求め、シャットオフ判定部１０に出力する。シャットオフ判定部１０では、負荷変動量ｄＴが第３の閾値を越えたことにより第１のシャットオフ指令を既に出力したか否かを判断し（図７のＳ４２）、まだ第１のシャットオフ指令を出力していなければ、負荷トルク推定部８の推定値が第２の閾値に達したことによるシャットオフ処理が既に行われているか否かを判断し（図７のＳ４３）、シャットオフ処理が行われていれば、モータ１を所定量だけ回転させた後停止させる第３のシャットオフ指令をモータ制御部１２に出力する（図７のＳ４６）。一方、シャットオフ処理が行われていなければ、シャットオフ判定部１０は、負荷変動量評価部１１の求めた負荷変動量ｄＴと第３の閾値との高低を比較し（図７のＳ４４）、負荷変動量ｄＴが第３の閾値以上になると、第１のシャットオフ指令をモータ制御部１２に出力する（図７のＳ４７）。また、既に第１のシャットオフ指令を出力しているか、又は、負荷変動量ｄＴが第３の閾値未満であれば、シャットオフ判定部１０は負荷トルク推定部８の推定値と第２の閾値との高低を比較し（図７のＳ４５）、負荷トルクの推定値が第２の閾値以上になると、第２のシャットオフ指令をモータ制御部１２に出力する（図７のＳ４８）。
【００４９】
而して、モータ制御部１２は、トリガスイッチ７の引き込み量に応じてモータ１の回転速度を制御するとともに、シャットオフ判定部１０からシャットオフ指令が入力されると、トリガスイッチ７の引き込み操作に関係なく、モータ１を停止させる。ここで、シャットオフ判定部１０から入力されたシャットオフ指令が第３の閾値による第１のシャットオフ指令の場合、モータ１を停止させた時点から所定の停止時間が経過するまでの間にトリガスイッチ７が開放されなければ、停止時間が経過した時点でモータ制御部１２はモータ１を再び回転させる。また、シャットオフ判定部１０から入力されたシャットオフ指令が第２の閾値による第２のシャットオフ指令の場合、モータ制御部１２はモータ１を停止させ、モータ１の再起動は行わない。一方、モータ制御部１２では、第１のシャットオフ指令が入力されるよりも前に第２のシャットオフ指令が入力された場合、モータ１を停止させた時点から所定の停止時間が経過するまでの間にトリガスイッチ７が開放されなければ、停止時間が経過した時点でモータ制御部１２は所定の時間モータ１を回転させた後、モータ１を停止させ、ねじ締め作業を終了する。
【００５０】
ところで、ねじ部材の種類やその組合せの設計によっては、シャットオフ判定部１０が第１のシャットオフ指令を出力することなく、負荷トルクの推定値が第２の閾値に達して第２のシャットオフ指令を出力する場合もあり得る。このような場合、モータ１が１回停止しただけで負荷トルクが適正締付トルクに達するため、適正締付トルクに達するまでにモータ１が停止する回数が作業者の予想する回数よりも少なくなり、第１のねじ部材の適正締付トルクでねじ締め作業が終了したのか、第２のねじ部材の適正締付トルクでねじ締め作業が終了したのか作業者が分からなくなる場合がある。
【００５１】
それに対して、本実施形態では、第１のシャットオフ指令が入力されるよりも前に第２のシャットオフ指令が入力された場合、モータ１を停止させた時点から所定の停止時間が経過するまでの間にトリガスイッチ７が開放されなければ、停止時間が経過した時点でモータ制御部１２は所定の時間モータ１を回転させた後、モータ１を停止させているので、締付トルクが第２のねじ部材の適正締付トルクに達するまでにモータ１が停止する回数を１回分増やして、２回に合わせることができ、第２のねじ部材の適正締付トルクでねじ部材が締め付けられたことを作業者に知らしめることができる。また、第３のシャットオフ指令によりモータ１が回転する回転量は十分小さいので、これによって締付トルク精度が大きく悪化するようなこともない。
【００５２】
ここで、図８はねじ締め作業の進行（すなわちハンマ３による打撃数Ｎ）に伴って変化する負荷トルク推定部８の推定トルクＴ及び負荷変動量評価部１１の求めた変動量ｄＴを示しており、負荷変動量ｄＴが第３の閾値Ｔｂ以上になった時点Ｐ２で、シャットオフ判定部１０は第１のシャットオフ指令をモータ制御部１２に出力し、モータ制御部１２がモータ１を所定の停止時間停止される。そして、停止時間が経過するまでの間にトリガスイッチ７が開放されなければ、停止時間の経過後にモータ制御部１２がモータ１の回転を再び開始させ、負荷トルク推定部８の推定トルクＴが第２の閾値Ｔａに達した時点Ｐ１で、シャットオフ判定部１０は第２のシャットオフ指令をモータ制御部１２に出力し、モータ制御部１２がモータ１を停止させる。
【００５３】
【発明の効果】
上述のように、請求項１の発明は、適正締付トルクのそれぞれ異なる複数種類のねじ部材の締緩作業に用いられる動力駆動回転工具において、ねじ部材の締緩を行うための出力軸と、出力軸を回転させる駆動部と、引き込み量に応じた操作信号を発生するトリガスイッチと、トリガスイッチから入力された操作信号に応じて駆動部の回転数を制御する駆動制御部と、出力軸にかかる負荷トルクを推定する負荷トルク推定部と、負荷トルク推定部の推定値の所定時間当たりの変動量を検出する負荷変動量検出部と、複数種類のねじ部材の適正締付トルクが予め設定され、負荷トルク推定部の推定値および負荷変動量検出部の検出結果に基づいて駆動部を所定の停止時間停止させる停止指令を駆動制御部に出力するシャットオフ判定部とを備え、シャットオフ判定部は、負荷トルク推定部の推定値と予め設定された複数の適正締付トルクとの高低を比較し、推定値が何れかの適正締付トルクに一致する毎に停止指令を駆動制御部に出力するとともに、負荷変動量検出部の検出した変動量が所定のしきい値以上になると停止指令を駆動制御部に出力し、駆動制御部は、シャットオフ判定部から停止指令が入力された場合、当該停止指令の入力時における負荷トルク推定部の推定値が、シャットオフ判定部に予め設定された複数の適正締付トルクのうち最も高い適正締付トルクでなければ、トリガスイッチの操作に関係無く駆動部を停止時間停止させるとともに、停止時間が経過するまでの間にトリガスイッチが開放されない場合は停止時間が経過した時点で駆動部を再び回転させ、停止指令の入力時における負荷トルク推定部の推定値が、シャットオフ判定部に予め設定された複数の適正締付トルクのうち最も高い適正締付トルクであれば、駆動部を停止させて、駆動部の再起動は行わないことを特徴とし、シャットオフ判定部は負荷トルクが各ねじ部材の適正締付トルクに達すると停止指令を駆動制御部に出力しており、駆動制御部では停止指令が入力されると、所定の停止時間だけ駆動部を停止させているので、この間にトリガスイッチを開放すれば、負荷トルクをこの時点の適正締付トルクとすることができる。一方停止時間が経過する間トリガスイッチを引き続けていれば、駆動制御部は駆動部の回転を再開させ、次に負荷トルクが適正締付トルクに達した時点でシャットオフ判定部から入力された停止指令により駆動部を停止させるから、負荷トルクが所望の適正締付トルクに達した時点でトリガスイッチを開放することにより、所望の適正締付トルクまでねじ部材を締め付けることができ、且つ駆動部の停止した回数で現在の締付トルクを把握することができる。したがって、締付トルクの設定作業を行うことなく、締付トルクの異なる複数のねじ部材のねじ締め作業を効率良く行うことができ、且つ従来の動力駆動回転工具のように締付トルクを設定するトルク設定器が不要になるから、動力駆動回転工具の小型化、低コスト化を図ることができるという効果がある。
【００５４】
しかも、樹脂グロメットのようなソフトジョイント部材のねじ締め作業を行う場合、着座直後にねじ締め作業を終了すれば、締付トルクが適正値となるが、シャットオフ判定部では、負荷変動量検出部の検出した変動量が所定のしきい値以上になると最初に停止指令を出力しているので、駆動制御部により駆動部が最初に停止された時点でトリガスイッチを開放すれば、負荷トルクの変動量が急激に増加した時点、すなわちねじ部材が着座した時点で駆動部を停止させることができ、適切な締付トルクでソフトジョイント部材のねじ締め作業を行えるという効果がある。
【００５５】
請求項２の発明は、請求項１の発明において、停止時間が略０．２秒以上且つ略１秒以下であることを特徴とし、停止時間は、負荷トルクが所望のトルクに達した時点でねじ締め作業を終了したい場合に作業者がトリガスイッチを離すだけの時間を確保できるような時間であって、且つ、ねじ締め作業を継続したい場合に駆動部が再起動されるまでの待ち時間を長く感じることがないような時間に設定するのが望ましく、停止時間としては略０．２秒以上且つ略１秒以下とするのが好ましい。
【００５６】
請求項３の発明は、請求項１又は２の発明において、停止時間の設定値を変化させるための停止時間設定部を設けたことを特徴とし、停止時間は、負荷トルクが所望のトルクに達した時点でねじ締め作業を終了したい場合に作業者がトリガスイッチを離すだけの時間を確保できるような時間であって、且つ、ねじ締め作業を継続したい場合に駆動部が再起動されるまでの待ち時間を長く感じることがないような時間に設定するのが望ましく、停止時間設定部により停止時間を所望の時間に設定することができるという効果がある。
【００５７】
請求項４の発明は、請求項１の発明において、負荷変動量検出部の検出した変動量がしきい値以上になっていない段階で、負荷トルク推定部の推定値が所望の適正締付トルクに達して、シャットオフ判定部から駆動制御部に停止指令が入力された場合、駆動制御部は、トリガスイッチの操作信号に関係なく駆動部を停止させ、駆動部を停止させてから停止時間が経過するまでの間にトリガスイッチが開放されない場合は停止時間が経過した時点で、駆動部の回転を作業者が認識できる程度の十分短い間だけ駆動部を回転させた後、駆動部を停止させることを特徴とし、ねじ部材の種類やその組合せの設計によっては、負荷変動量検出部の検出した変動量がしきい値以上になっていない段階で、負荷トルク推定部の推定値がねじ部材の適正締付トルクに達する場合もあり、このような場合、所望の適正締付トルクに達するまでに駆動部が停止する回数が作業者の予想する回数よりも１回分少なくなり、所望のトルクでねじ締め作業が終了したのか作業者が分からなくなる場合があるが、負荷変動量検出部の検出した変動量がしきい値以上になっていない段階で、負荷トルク推定部の推定値が所望の適正締付トルクに達して、シャットオフ判定部から駆動制御部に停止指令が入力された場合、駆動部を停止させた時点から所定の停止時間が経過するまでの間にトリガスイッチが開放されなければ、停止時間が経過した時点で駆動制御部は所定の時間駆動部を回転させた後、停止させているので、締付トルクが所望の適正締付トルクに達するまでに駆動部が停止する回数を１回分増やして補正することができるから、所望の適正締付トルクでねじ部材が締め付けられたことを作業者に知らしめることができ、且つこの場合に駆動制御部が回転させる駆動部の回転量は十分小さいので、これによって締付トルク精度が大きく悪化するようなこともない。
【図面の簡単な説明】
【図１】 本発明に係るインパクト回転工具の基本構成を示すブロック図である。
【図２】 同上の動作を説明するフローチャートである。
【図３】 同上の別の動作を説明するフローチャートである。
【図４】 実施形態１のインパクト回転工具のブロック図である。
【図５】 同上の動作を説明するフローチャートである。
【図６】 実施形態２のインパクト回転工具のブロック図である。
【図７】 実施形態３のインパクト回転工具の動作を説明するフローチャートである。
【図８】 同上の打撃回数とトルクとの関係を説明する説明図である。
【図９】 従来のインパクト回転工具のブロック図である。
【符号の説明】
１ モータ
６ 出力軸
７ トリガスイッチ
８ 負荷トルク推定部
１０ シャットオフ判定部
１２ モータ制御部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power-driven rotary tool such as an impact wrench or impact driver used for tightening and loosening screws such as bolts and nuts.
[0002]
[Prior art]
As this type of power-driven rotary tool, as shown in FIG. 9, the hammer 3 is rotationally driven by the motor 1, and the output shaft 5 is rotated by applying a hammering impact by the hammer 3 to the output shaft 5. Impact rotating tools such as impact drivers and impact wrench that perform tightening and loosening operations on screws such as bolts and nuts are provided by using a driver bit 6 and a socket wrench.
[0003]
The impact rotary tool includes a load torque estimating unit 8 that estimates torque applied to the output shaft 5, a limit torque setting unit 20 for setting a tightening torque according to a member to be tightened, and an estimated value of the load torque estimating unit 8. And the setting value of the tightening torque set by the limit torque setting unit 20, it is determined whether or not the screw member is seated. When the screw member is seated, the motor 1 is stopped (shut off). And a shut-off determination unit 10 that generates a stop command (shut-off command).
[0004]
When the screw tightening operation is performed, the shut-off determination unit 10 compares the estimated value of the load torque estimating unit 8 with the set value of the limit torque setting unit 20, and the estimated value of the load torque estimating unit 8 is When the set value of the tightening torque was exceeded, it was determined that the screw member was seated, and the rotation of the motor 1 was stopped.
[0005]
[Problems to be solved by the invention]
In the impact rotary tool described above, the screw tightening operation is performed after the tightening torque is set in advance according to the type of the screw member to be tightened using the limit torque setting device 20 when performing the screw tightening operation. Therefore, when performing a screw tightening operation for a plurality of types of screw members having different tightening torques, it is necessary to set the tightening torque for each of the different types of screw members, and there is a problem in that the setting work is troublesome.
[0006]
Therefore, among the screw members with different tightening torques, the setting work of the tightening torque can be reduced to some extent by setting the same value for the tightening torque for the screw members having the same allowable torque range. However, for screw members that do not overlap in the allowable torque range, it is necessary to change the setting of the tightening torque, and there is a problem that workability is poor. In addition, there is a limit to the common tightening torque, and when the common tightening torque is near the boundary of the allowable torque range, the tightening torque is insufficient due to variations in the manufacturing of screw members, etc. Therefore, the screw member may be stopped, or an excessive tightening torque may be applied to cause the screw member to penetrate the mating member, or the screw member may be damaged.
[0007]
Furthermore, when setting the tightening torque using the limit torque setting device 20, if a value lower than the appropriate value is set by mistake, the tightening torque is insufficient and the screw member is being tightened. It was necessary to stop and retighten the screw. Moreover, if a value higher than the appropriate value is set, excessive tightening torque is applied to the screw member, and the screw member penetrates the mating member or the screw member is damaged. In some cases, the replacement work may be necessary, and the quality of screw tightening may be deteriorated.
[0008]
In addition, a thread groove is not formed on the surface, and a synthetic resin member such as a resin grommet that performs screw tightening while cutting the thread groove by screwing into the screw hole (hereinafter referred to as “soft joint member”). In addition, when the screw tightening operation of the metal screw member (hereinafter referred to as “hard joint member”) is performed using the above-described impact rotating tool, the change rate of the estimated torque value reaches a predetermined value. Then, it is determined that the screw member is a soft joint member, the screw tightening operation is stopped regardless of the tightening torque, and the screw member is a hard joint member if the change rate of the estimated torque value is less than a predetermined value. When the tightening torque reaches the appropriate tightening torque for the hard joint member, the tightening torque setting operation is made unnecessary by stopping the screw tightening operation. Although a method has been proposed, it is impossible to set a plurality of tightening torque in the case of a hard joint member, there is a problem that the same hard joint member tightening torque only simultaneously perform the screw tightening operation.
[0009]
Moreover, when the screw member is screwed with a spring washer between the screw hole formed in the iron plate after baking coating is applied to the iron plate in which the screw hole is formed, the screw member is removed while removing the paint adhering to the screw hole. After screwing into the screw hole, the spring washer is crushed by the screw member, so the transition of the load torque is very similar to the transition of the load torque generated when tightening the soft joint member described above, and the two cannot be distinguished. There is a case. Therefore, despite the fact that the hard joint member is tightened in the screw hole provided in the iron plate, the shut-off determination unit 10 determines that it is a soft joint member, and stops the tightening work at a small tightening torque stage. There was also a problem that the tightening torque was insufficient.
[0010]
The present invention has been made in view of the above-described problems, and the object of the present invention is to reliably perform screw tightening work of a plurality of types of screw members having different tightening torques without performing tightening torque setting work. It is in providing the power drive rotary tool which can be performed to.
[0011]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, in a power-driven rotary tool used for tightening and tightening a plurality of types of screw members having different proper tightening torques, an output for tightening and tightening the screw members is provided. A shaft, a drive unit that rotates the output shaft, a trigger switch that generates an operation signal according to the pull-in amount, a drive control unit that controls the rotation speed of the drive unit according to the operation signal input from the trigger switch, A load torque estimation unit for estimating a load torque applied to the output shaft;,negativeA load fluctuation amount detecting unit for detecting a fluctuation amount per predetermined time of the estimated value of the load torque estimating unit;The drive control unit issues a stop command to stop the drive unit for a predetermined stop time based on an estimated value of the load torque estimation unit and a detection result of the load fluctuation amount detection unit, in which appropriate tightening torques for a plurality of types of screw members are preset. A shut-off determination unit that outputs toWithThe shut-off determination unit compares the estimated value of the load torque estimation unit with a plurality of preset appropriate tightening torques, and drives a stop command each time the estimated value matches any of the appropriate tightening torques. In addition to outputting to the control unit, when the fluctuation amount detected by the load fluctuation amount detection unit is equal to or greater than a predetermined threshold, a stop command is output to the drive control unit,When a stop command is input from the shut-off determination unit, the drive control unitLoad torque estimation unitEstimated value isUnless the highest proper tightening torque among the plurality of proper tightening torques set in advance in the shut-off determination unit, the drive unit is stopped for the stop time regardless of the operation of the trigger switch, and until the stop time elapses. BetweenIf the trigger switch is not released during this time, rotate the drive again when the stop time has elapsed.LetWhen a stop command is inputIf the estimated value of the load torque estimation unit is the highest proper tightening torque among a plurality of proper tightening torques preset in the shut-off determination unit, the drive unit is stopped and the drive unit is restarted. Not performedThe shut-off determination unit outputs a stop command to the drive control unit when the load torque reaches an appropriate tightening torque of each screw member. When the stop command is input to the drive control unit, a predetermined command is output. Since the drive unit is stopped only for the stop time, the load torque can be set to the appropriate tightening torque at this point if the trigger switch is opened during this time. On the other hand, if the trigger switch is continuously pulled while the stop time elapses, the drive control unit restarts the rotation of the drive unit, and then is input from the shut-off determination unit when the load torque reaches the appropriate tightening torque. Since the drive unit is stopped by the stop command, the screw member can be tightened to the desired proper tightening torque by opening the trigger switch when the load torque reaches the desired proper tightening torque, and the drive unit The current tightening torque can be grasped by the number of times of stopping. Therefore, it is possible to efficiently perform the screw tightening operation of a plurality of screw members having different tightening torques without performing the tightening torque setting operation, and to set the tightening torque as in a conventional power-driven rotary tool. Since the torque setting device is not necessary, the power-driven rotary tool can be reduced in size and cost.
[0012]
  Moreover,When performing screw tightening work for soft joint members such as resin grommets, the tightening torque will be an appropriate value if the screw tightening work is completed immediately after seating, but the shut-off determination unit detects the load fluctuation amount detection unit. Since the stop command is output first when the amount of fluctuation exceeds the predetermined threshold, if the trigger switch is opened when the drive unit is first stopped by the drive control unit, the amount of load torque fluctuation will be The drive part can be stopped at the time when it suddenly increases, that is, when the screw member is seated, and the screw tightening operation of the soft joint member can be performed with an appropriate tightening torque.
[0013]
  Claim2In the invention of claim1'sIn the invention, the stop time is approximately 0.2 seconds or more and approximately 1 second or less, and the stop time is determined by the operator when the operator wants to finish the screw tightening operation when the load torque reaches a desired torque. Set the time so that the trigger switch can be released, and when the screw tightening operation is to be continued, the waiting time until the drive unit is restarted is not felt long. It is desirable that the stop time is approximately 0.2 seconds or more and approximately 1 second or less.
[0014]
  Claim3In the invention of claim1 or 2In the present invention, a stop time setting unit for changing the set value of the stop time is provided, and the stop time is determined by the operator when the screw tightening operation is to be terminated when the load torque reaches a desired torque. Is set to a time that can ensure the time to release the trigger switch and not to feel the waiting time until the drive is restarted when the screw tightening operation is to be continued. Preferably, the stop time can be set to a desired time by the stop time setting unit.
[0015]
  Claim4In the invention of claim1In this invention, when the fluctuation amount detected by the load fluctuation amount detection unit is not equal to or greater than the threshold value, the estimated value of the load torque estimation unit reaches a desired appropriate tightening torque and is driven from the shut-off determination unit. When a stop command is input to the control unit, the drive control unit stops the drive unit regardless of the operation signal of the trigger switch, and the trigger switch is released after the drive unit is stopped until the stop time elapses. If not, when the stop time has elapsed, the drive unit is rotated for a sufficiently short time that the operator can recognize the rotation of the drive unit, and then the drive unit is stopped. Depending on the design of the combination, the estimated value of the load torque estimation unit may reach the appropriate tightening torque of the screw member when the variation detected by the load variation detection unit does not exceed the threshold value. In such a case, the number of times that the drive unit stops before reaching the desired appropriate tightening torque is one less than the number of times expected by the operator, and the operator knows whether the screw tightening operation has been completed with the desired torque. The estimated value of the load torque estimation unit reaches the desired proper tightening torque when the variation detected by the load variation detection unit is not equal to or greater than the threshold value, and the shut-off determination unit When a stop command is input to the drive control unit, if the trigger switch is not released between the time when the drive unit is stopped and the predetermined stop time elapses, the drive control unit is Since it is stopped after rotating the drive unit for a predetermined time, it can be corrected by increasing the number of times the drive unit stops until the tightening torque reaches the desired appropriate tightening torque. The operator can be informed that the screw member has been tightened with the desired proper tightening torque, and in this case, the amount of rotation of the drive unit rotated by the drive control unit is sufficiently small. There will be no major deterioration.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0017]
  (Basic configuration)
  Of the present inventionBasic configurationWill be described with reference to FIGS. This power-driven rotary tool rotates the hammer 3 by the motor 1, rotates the output shaft 5 by applying a striking impact by the hammer 3 to the output shaft 5, a driver bit 6 attached to the output shaft 5, a socket, etc. The impact rotating tool such as an impact driver or impact wrench that performs tightening and loosening operations on screws such as bolts and nuts by using a bit, and the following is used as an impact structure by the hammer 3. That is, a cylindrical hammer 3 is rotatably disposed on the outer periphery of the drive shaft 2a to which the rotation of the motor 1 is decelerated and transmitted by the speed reducer 2 including a planetary speed reduction mechanism. The drive shaft 2a and the hammer 3 are restrained from moving in the axial direction and in the direction around the axis by a cam mechanism (not shown) formed in FIG. The hammer 3 that is biased toward the output shaft 5 by the spring 4 hits the anvil 5a that projects from the rear end of the output shaft 5 to the side at the front end surface thereof. 3a is provided.
[0018]
Thus, in the state where the load is hardly applied to the output shaft 5 to which the driver bit 6 and the socket are attached at the tip, the rotation of the drive shaft 2a is transmitted to the hammer 3 through the cam mechanism, and the hammer 3 Is transmitted to the output shaft 5 by the engagement between the striking portion 3a and the anvil 5a. When the load applied to the output shaft 5 increases, relative rotation within the range permitted by the cam mechanism occurs between the hammer 3 and the drive shaft 2a, and the hammer 3 is guided to the spring 4 by being guided by the cam mechanism. When the striking part 3a and the anvil 5a are disengaged and the striking part 3a gets over the anvil 5a, the hammer 3 is guided to the cam mechanism by the restoring force of the spring 4 and moves forward to the anvil 5a. The striking portion 3a is impacted and a rotational force is applied to the output shaft 5 by the impact. Here, a striking mechanism for applying a rotational force by a striking impact to the output shaft 5 from the hammer 3, the spring 4, the anvil 5a, and the like is configured.
[0019]
  By the way, the motor control unit 12 as the drive control unit controls the rotation speed of the motor 1 in accordance with the pulling amount of the trigger switch 7.TheThe rotation speed of the motor 1 is variably controlled by adjusting the power supplied from the rechargeable battery 14 to the motor 1 in accordance with a control signal input from the motor control unit 12 by the data control circuit 13. That is, the motor control circuit 13 is a drive circuit that turns on / off the switching element in accordance with a switching element inserted in a power supply path from the rechargeable battery 14 to the motor 1 and a control signal input from a motor control unit 12 described later. And, for example, by varying the on-duty ratio of the switching element in accordance with a control signal input from the motor control unit 12, the supplied power is adjusted to vary the rotational speed of the motor 1. .
[0020]
  AlsoThis rotating toolFor example, the load torque estimating unit 8 that estimates the load torque applied to the output shaft 5 from the transition of the rotation speed of the motor 1 and the screw member seated from the estimated value of the load torque estimating unit 8 are determined and the motor 1 is stopped. The shut-off determination unit 10 outputs a shut-off command (stop command) to the motor control unit 12, and the motor control unit 12 activates the motor control circuit 13 when the shut-off command is input from the shut-off determination unit 10. The rotation of the motor 1 is stopped by controlling. For example, the load torque estimation unit 8 calculates a moving average of the estimated values for the past four times, and outputs the average value to the shutoff determination unit 10 as an estimated value. The load torque estimating method by the load torque estimating unit 8 is not limited to the above method. For example, a torque sensor is used, the current amount or voltage amount of the motor 1, the bit advance angle, the bounce of the hammer 3. The load torque may be estimated from the amount or the like. Also,This rotating toolThe load torque estimating unit 8, the shut-off determining unit 10, and the motor control unit 12 are configured by a microcomputer.
[0021]
  The shut-off determination unit 10 includes an appropriate tightening torque for the first screw member (hereinafter referred to as a first threshold) and an appropriate tightening torque for the second screw member (hereinafter referred to as a second threshold). )) Is set in advance, and the second threshold value is set higher than the first threshold value. still,This rotating toolThen, the case where the tightening operation | work of two types of screw members from which appropriate tightening torque differs is demonstrated as an example.
[0022]
Here, the load torque estimation unit 8 outputs an estimated value of the load torque every time the hammer 3 is hit, and the load torque estimation unit 8 inputs the estimated value of the load torque to the shut-off determination unit 10. Then, the shut-off determination unit 10 compares the estimated value of the load torque with the first and second threshold values. When the estimated value of the load torque reaches the first threshold value, the first shut-off command is controlled by the motor. When the estimated value of the load torque reaches the second threshold value, a second shut-off command is output to the motor control unit 12.
[0023]
The motor control unit 12 controls the rotation speed of the motor 1 according to the pulling amount of the trigger switch 7, and when a shutoff command is input from the shutoff determination unit 10, regardless of the pulling operation of the trigger switch 7, The motor 1 is stopped. Here, when the shut-off command input from the shut-off determination unit 10 is the first shut-off command based on the first threshold value, the trigger is performed from when the motor 1 is stopped until a predetermined stop time elapses. If the switch 7 is not opened, the motor control unit 12 rotates the motor 1 again when the stop time has elapsed. On the other hand, when the shut-off command input from the shut-off determination unit 10 is the second shut-off command based on the second threshold, the motor control unit 12 stops the motor 1 and does not restart the motor 1.
[0024]
The control operation of the motor 1 will be described below with reference to the flowchart of FIG. After each part is initialized when the power is turned on (S2 in FIG. 2), the motor control unit 12 reads an input from the trigger switch 7 (S3 in FIG. 2), and determines whether the trigger switch 7 has been pulled in by the operator. When the trigger switch 7 is pulled in (S4 in FIG. 2), the motor 1 is started (S5 in FIG. 2).
[0025]
Thereafter, the motor control unit 12 monitors whether the trigger switch 7 is opened or whether a shut-off command is input from the shut-off determination unit 10 (S6 in FIG. 2), and the trigger switch 7 is opened. If no shut-off command is input, a rotation process for rotating the motor 1 is performed (S8 in FIG. 2), and the input from the trigger switch 7 is read (S9 in FIG. 2), and then in S6 in FIG. Returning and repeating the above-described processing, the rotation control of the motor 1 is performed according to the pull-in amount of the trigger switch 7 until the trigger switch 7 is opened or a shut-off command is input.
[0026]
On the other hand, when the trigger switch 7 is opened or a shut-off command is input from the shut-off determination unit 10, the motor control unit 12 outputs a stop signal for temporarily stopping the motor 1 to the motor control circuit 13. Then, the process of temporarily stopping the motor 1 is performed (S7 in FIG. 2), and it is determined whether or not the shut-off command input from the shut-off determining unit 10 is the first shut-off command based on the first threshold value. (S10 in FIG. 2).
[0027]
Here, if the shutoff command is based on the first threshold value, the motor control unit 12 reads the input from the trigger switch 7 (S12 in FIG. 2), and determines whether the trigger switch 7 is opened. (S13 in FIG. 2). If the trigger switch 7 is not opened, it is determined whether or not a predetermined stop time has elapsed since the motor 1 was stopped (S14 in FIG. 2). If the stop time has not elapsed, the process again returns to S12. Returning and repeating the above process, if the stop time has elapsed, after performing the restart process to rotate the motor 1 again (S16 in FIG. 2), the process returns to S6 in FIG. 2 and the above process is repeated.
[0028]
  If the shutoff command is not based on the first threshold or the trigger switch 7 is opened before the stop time elapses, the motor control unit 12 reads the input from the trigger switch 7 (FIG. 2). S11), it is determined whether or not the trigger switch 7 is opened (S15 in FIG. 2), and when the trigger switch 7 is opened, FIG.S3Return to.
[0029]
By the way, every time a hit by the hitting mechanism occurs, an interrupt is generated, and a shut-off determination process described later is performed. The shut-off determination process will be described below with reference to the flowchart of FIG.
[0030]
When an impact is generated by the impact mechanism, the load torque estimation unit 8 estimates the load torque applied to the driver bit 6 from the rotation speed of the motor 1 during the impact and the rotation speed of the motor 1 at the time of impact, and outputs it to the shut-off determination unit 10 (S21 in FIG. 3). When the estimated value of the load torque is input from the load torque estimating unit 8, the shut-off determining unit 10 determines whether or not the first shut-off command has already been generated (S22 in FIG. 3). If the first shut-off command has not been generated, the load torque estimated value (estimated torque) is compared with the first threshold value (S23 in FIG. 3). When the estimated value of the load torque reaches the first threshold value, a first shut-off command is output to the motor control unit 12 (S25 in FIG. 3). On the other hand, if the first shut-off command has already been generated or the estimated value of the load torque is equal to or less than the first threshold value, the shut-off determination unit 10 determines whether the estimated value of the load torque and the second threshold value are the same. The levels are compared (S24 in FIG. 3), and when the estimated value of the load torque reaches the second threshold value, a second shut-off command is output to the motor control unit 12 (S26 in FIG. 3).
[0031]
Thus, when the estimated torque of the load torque estimating unit 8 reaches the first threshold value, the shut-off determining unit 10 outputs a first shut-off command to the motor control unit 12, and the motor control unit 12 Since the rotation of the motor 1 is stopped for a predetermined stop time according to the shut-off command, if the trigger switch 7 is opened when the rotation of the motor 1 stops, the tightening torque of the screw member is set to the first threshold value. The first screw member can be tightened with an appropriate tightening torque. On the other hand, when the screwing operation of the second screw member is performed, if the trigger switch 7 is continuously pulled even after the motor 1 is stopped, the motor is stopped when a predetermined stop time elapses from when the motor 1 is stopped. Since the control unit 12 rotates the motor 1 again and can stop the motor 1 when the load torque reaches the second threshold, the screw tightening operation of the second screw member is performed with an appropriate tightening torque. be able to.
[0032]
  In addition,This rotating toolIn the above description, the case where two types of screw members having different proper tightening torques are tightened has been described. However, the proper tightening torque of three or more types of screw members is set in the shut-off determination unit 10, and the load torque estimating unit is set. When the estimated value of 8 reaches an appropriate tightening torque for each screw member, the shut-off determination unit 10 may output a stop command to the motor control unit 12, and the motor control unit 12 may output the shut-off determination unit 10. When a stop command is input from, the motor 1 is stopped regardless of the operation signal of the trigger switch 7, and the trigger switch 7 is not released until a predetermined stop time elapses after the motor 1 is stopped. When the stop time elapses, the motor 1 is rotated again, and the estimated torque of the load torque estimation unit 8 reaches the proper tightening torque of the screw member having the highest proper tightening torque. By repeating the above, as in the case described above, even when three or more types of screw members are tightened, a plurality of screw members having different proper tightening torques can be tightened without performing tightening torque setting operations. Since it can be performed efficiently and a torque setting device for setting the tightening torque as in the conventional power-driven rotary tool is not required, the power-driven rotary tool can be reduced in size and cost. Further, the current tightening torque can be grasped from the number of stops of the motor 1.
[0033]
  The stop time for the motor control unit 12 to temporarily stop the rotation of the motor 1 is triggered when the operator wants to finish the screw tightening operation when the load torque reaches the appropriate tightening torque of the first screw member. When it is a time that can secure the time for releasing the switch 7 and when it is desired to complete the screw tightening operation when the load torque reaches the proper tightening torque of the second screw member, the motor 1 is restarted. It is desirable to set the time so that you do not feel long waiting time until starting,This rotating toolThen, for example, it is set to approximately 0.45 seconds. The stop time is not limited to 0.45 seconds, but may be set as appropriate so as to satisfy the above conditions. For example, the stop time is set to about 0.2 seconds or more and about 1 second or less. Is preferred.
[0034]
  (Embodiment1)
  Embodiment of the present invention1Will be described with reference to FIGS. In this embodiment,Described in the basic configurationThe power-driven rotary tool is provided with a load fluctuation amount evaluation unit (load fluctuation amount detection unit) 11 that calculates the fluctuation amount of the load torque from the transition of the estimated value of the load torque estimated by the load torque estimation unit 8. The configuration other than the load fluctuation amount evaluation unit 11 isBasic configurationTherefore, the same components are denoted by the same reference numerals, and the description thereof is omitted.
[0035]
The load torque estimator 8 estimates the load torque each time a hit by the hitting mechanism occurs, and outputs the estimation result to the shutoff determination unit 10 and the load fluctuation amount evaluation unit 11. The load fluctuation amount evaluating unit 11 may output the difference between the estimated value of the load torque estimating unit 8 when the previous hit occurs and the estimated value of the load torque estimating unit 8 when the next hit occurs as the fluctuation amount. However, when considering noise resistance, it is desirable to perform band pass filtering. As an example of the bandpass filter processing, there is a method in which the load fluctuation amount evaluating unit 11 calculates a short-term moving average and a long-term moving average of the estimated values of the load torque estimating unit 8 and outputs the difference between the two as a fluctuation amount. . For example, the load fluctuation amount evaluating unit 11 calculates a moving average of four estimated values up to the present as a short-term moving average, calculates a moving average of 16 estimated values up to the present as a long-term moving average, When the load fluctuation amount dT is obtained by obtaining the difference, assuming that the estimated values of the load torque output by the load torque estimation unit 8 so far are T1, T2, T3,..., T20, the load fluctuation amount dT is as follows. It is expressed by an expression.
[0036]
[Expression 1]

[0037]
Then, when the load fluctuation amount dT calculated by the load fluctuation amount evaluation unit 11 is equal to or greater than a predetermined threshold value (hereinafter referred to as a third threshold value), the shut-off determination unit 10 issues a first shut-off command. While outputting to the motor control part 12, if the estimated value of load torque reaches a 2nd threshold value, a 2nd shutoff command will be output to the motor control part 12.
[0038]
  Here, the shut-off determination process will be described with reference to the flowchart of FIG. The control operation of the motor 1 isBasic configurationSince this is the same, the description thereof is omitted.
[0039]
When an impact is generated by the impact mechanism, the load torque estimation unit 8 estimates the load torque applied to the driver bit 6 from the rotation speed of the motor 1 during the impact and the rotation speed of the motor 1 at the impact, and the shut-off determination unit 10 and the load It outputs to the fluctuation amount evaluation part 11 (S31 of FIG. 5). The load fluctuation amount evaluation unit 11 obtains the load fluctuation amount dT of the load torque from the estimated value of the load torque estimation unit 8 and outputs it to the shutoff determination unit 10. The shut-off determination unit 10 determines whether or not the first shut-off command based on the third threshold has already been output (S32 in FIG. 5), and if the first shut-off command is not output, the load fluctuation is determined. The load fluctuation amount dT obtained by the quantity evaluation unit 11 is compared with the third threshold value (S33 in FIG. 5). If the load fluctuation amount dT is equal to or greater than the third threshold value, the first shut-off command is output to the motor control unit 12 (S35 in FIG. 5). On the other hand, if the first shut-off command has already been output or the load fluctuation amount dT is less than the third threshold value, the shut-off determination unit 10 compares the estimated torque with the second threshold value. (S34 in FIG. 5) When the estimated torque reaches the second threshold, a second shut-off command is output to the motor control unit 12 (S36 in FIG. 5).
[0040]
By the way, when the screw tightening operation of the soft joint member described above is performed, if the screw tightening operation is finished immediately after the seating, the tightening torque becomes an appropriate value. By detecting the seating and terminating the screw tightening operation, the soft joint member can be tightened with an appropriate tightening torque. That is, in this embodiment, when the load fluctuation amount dT of the load torque obtained by the load fluctuation amount evaluation unit 11 becomes equal to or greater than the third threshold value, the shutoff determination unit 10 outputs the first shutoff command to the motor control unit 12. Since the motor control unit 12 stops the rotation of the motor 1, when the soft joint member is screwed, the trigger switch 7 is opened when the rotation of the motor 1 is stopped first. The screw tightening operation can be terminated immediately after the soft joint member is seated, and the soft joint member can be tightened with an appropriate tightening torque. On the other hand, when the screwing operation of the hard joint member is performed, if the trigger switch 7 is continuously pulled even after the motor 1 is stopped for the first time, the motor is stopped when a predetermined stop time elapses from when the motor 1 is stopped. When the control unit 12 rotates the motor 1 again and the load torque reaches the second threshold value, the shut-off determination unit outputs a second shut-off command to the motor control unit 12 to stop the motor 1. Therefore, the screwing operation of the hard joint member can be performed with an appropriate tightening torque.
[0041]
Note that the stop time for the motor control unit 12 to temporarily stop the rotation of the motor 1 is that the operator switches the trigger switch 7 when it is desired to end the screw tightening operation when the load torque fluctuation amount exceeds the third threshold value. The motor 1 is restarted when it is sufficient to ensure a sufficient time to release the screw and when the load torque reaches the proper tightening torque of the second screw member and the screw tightening operation is to be completed. It is desirable to set the waiting time until it does not feel long. In this embodiment, the waiting time is set to approximately 0.45 seconds, for example. The stop time is not limited to 0.45 seconds, but may be set as appropriate so as to satisfy the above conditions. For example, the stop time is set to about 0.2 seconds or more and about 1 second or less. Is preferred.
[0042]
  In the present embodiment, the case where the tightening operation of the two types of screw members of the soft joint member and the hard joint member is described as an example.Basic configurationAs described in the above, when the appropriate tightening torque values of the plurality of hard joint members are set in the shut-off determining unit 10 and the estimated value of the load torque reaches each appropriate tightening torque, the shut-off determining unit 10 It goes without saying that a shut-off command may be output to the motor control unit 12 and the tightening operation of the soft joint member and a plurality of hard joint members having different proper tightening torques may be performed.
[0043]
  (Embodiment2)
  Embodiment of the present invention2Will be described with reference to FIG. In this embodiment, the embodiment1In the power driven rotary tool, a shutoff command based on the third threshold value is input from the shutoff determination unit 10 to the motor control unit 12, and the motor control unit 12 temporarily stops the motor 1 by the shutoff command. A restart standby time setting unit (stop time setting unit) 15 for changing the set value of the stop time (restart standby time) until 1 is restarted is provided. The configuration other than the restart waiting time setting unit 15 is the embodiment.1Therefore, the same components are denoted by the same reference numerals, and the description thereof is omitted.
[0044]
Here, the restart waiting time setting unit 15 is provided with, for example, a dial type operation knob. By rotating the operation knob, the stop time is set to a range of, for example, about 0.2 seconds or more and about 1 second or less, preferably It can be changed in the range of about 0.25 seconds or more and about 1 second or less. As described above, the stop time is a time that allows the operator to secure a time enough to release the trigger switch 7 when the screw tightening operation is to be terminated when the load torque fluctuation amount becomes equal to or greater than the third threshold value. If the load torque reaches the proper tightening torque of the second screw member and the screw tightening operation is to be completed, the waiting time until the motor 1 is restarted is not felt long. It is desirable to set the stop time to a minimum time, but since the stop time setting can be changed by the restart waiting time setting unit 15, the stop time is set to the minimum necessary time according to the skill level of the worker. Thus, the working time can be shortened.
[0045]
  In this embodiment, the embodiment1In the power driven rotary tool, there is provided a restart standby time setting unit 15 for changing the set value of the stop time.Described in the basic configurationThe power-driven rotating tool may be provided with the restart waiting time setting unit 15 of the present embodiment, and the same effect as described above can be obtained.
[0046]
  (Embodiment3)
  Embodiment of the present invention3Will be described with reference to FIG. The configuration of the power driven rotary tool is the embodiment.1Therefore, description thereof is omitted, and only different portions will be described.
[0047]
  The shut-off determination unit 10 is an embodiment1Similarly, when the load fluctuation amount dT calculated by the load fluctuation amount evaluation unit 11 is equal to or greater than the third threshold, the first shut-off command is output to the motor control unit 12 and the estimated value of the load torque is the second value. When the threshold is reached, a second shut-off command is output to the motor control unit 12. In the shut-off determination unit 10, the load torque fluctuation amount dT obtained by the load fluctuation amount evaluation unit 11 is not equal to or greater than the third threshold value (that is, the first shut-off command is not output). When the estimated value of the load torque estimated by the load torque estimating unit 8 reaches the second threshold value and the second shut-off command is output, the rotation of the motor 1 is only short enough to allow the operator to recognize the rotation. A third shut-off command for stopping after rotating the motor 1 is output to the motor control unit 12.
[0048]
Here, the shut-off determination process will be described with reference to the flowchart of FIG. When an impact is generated by the impact mechanism, the load torque estimation unit 8 estimates the load torque applied to the driver bit 6 from the rotation speed of the motor 1 during the impact and the rotation speed of the motor 1 at the impact, and the shut-off determination unit 10 and the load It outputs to the fluctuation amount evaluation part 11 (S41 of FIG. 7). The load fluctuation amount evaluation unit 11 obtains the load fluctuation amount dT of the load torque from the estimated value of the load torque estimation unit 8 and outputs it to the shutoff determination unit 10. The shut-off determination unit 10 determines whether or not the first shut-off command has already been output when the load fluctuation amount dT exceeds the third threshold (S42 in FIG. 7), and the first shut-off is still in progress. If the command is not output, it is determined whether or not the shutoff process due to the estimated value of the load torque estimating unit 8 reaching the second threshold has already been performed (S43 in FIG. 7), and the shutoff process is performed. If this is done, a third shutoff command for rotating the motor 1 by a predetermined amount and then stopping it is output to the motor controller 12 (S46 in FIG. 7). On the other hand, if the shut-off process has not been performed, the shut-off determination unit 10 compares the load fluctuation amount dT obtained by the load fluctuation amount evaluation unit 11 with the third threshold (S44 in FIG. 7). When the load fluctuation amount dT is equal to or greater than the third threshold value, a first shut-off command is output to the motor control unit 12 (S47 in FIG. 7). If the first shut-off command has already been output or if the load fluctuation amount dT is less than the third threshold value, the shut-off determination unit 10 determines the estimated value of the load torque estimation unit 8 and the second threshold value. (S45 in FIG. 7), and when the estimated value of the load torque becomes equal to or greater than the second threshold value, a second shut-off command is output to the motor control unit 12 (S48 in FIG. 7).
[0049]
Thus, the motor control unit 12 controls the rotation speed of the motor 1 in accordance with the pull-in amount of the trigger switch 7, and when the shut-off command is input from the shut-off determination unit 10, the pull-in operation of the trigger switch 7 is performed. Regardless of whether the motor 1 is stopped. Here, when the shut-off command input from the shut-off determination unit 10 is the first shut-off command based on the third threshold value, the trigger is performed from when the motor 1 is stopped until a predetermined stop time elapses. If the switch 7 is not opened, the motor control unit 12 rotates the motor 1 again when the stop time has elapsed. When the shut-off command input from the shut-off determination unit 10 is the second shut-off command based on the second threshold, the motor control unit 12 stops the motor 1 and does not restart the motor 1. On the other hand, in the motor control unit 12, when the second shut-off command is input before the first shut-off command is input, the predetermined stop time elapses from the time when the motor 1 is stopped. If the trigger switch 7 is not opened during this time, the motor control unit 12 rotates the motor 1 for a predetermined time when the stop time has elapsed, stops the motor 1 and ends the screw tightening operation.
[0050]
By the way, depending on the type of the screw member and the combination thereof, the estimated value of the load torque reaches the second threshold value without the shut-off determination unit 10 outputting the first shut-off command, and the second shut-off value is reached. A command may be output. In such a case, since the load torque reaches the appropriate tightening torque just by stopping the motor 1 once, the number of times that the motor 1 stops before reaching the appropriate tightening torque is less than the number of times expected by the operator. The operator may not know whether the screw tightening operation has been completed with the proper tightening torque of the first screw member or whether the screw tightening operation has been completed with the proper tightening torque of the second screw member.
[0051]
On the other hand, in this embodiment, when the second shut-off command is input before the first shut-off command is input, a predetermined stop time elapses from the time when the motor 1 is stopped. If the trigger switch 7 is not released before the motor control unit 12 rotates the motor 1 for a predetermined time after the stop time has elapsed, the motor 1 is stopped. The number of times that the motor 1 stops before reaching the proper tightening torque of the screw member 2 can be increased by one, and the screw member can be tightened with the proper tightening torque of the second screw member. This can be made known to the worker. Further, since the rotation amount by which the motor 1 is rotated by the third shut-off command is sufficiently small, the tightening torque accuracy is not greatly deteriorated.
[0052]
Here, FIG. 8 shows the estimated torque T of the load torque estimating unit 8 and the variation dT obtained by the load variation evaluating unit 11 that change with the progress of the screw tightening operation (that is, the number of hits N by the hammer 3). At time P2 when the load fluctuation amount dT becomes equal to or greater than the third threshold value Tb, the shut-off determination unit 10 outputs a first shut-off command to the motor control unit 12, and the motor control unit 12 sets the motor 1 to a predetermined value. The stop time is stopped. If the trigger switch 7 is not opened before the stop time elapses, the motor control unit 12 restarts the rotation of the motor 1 after the stop time elapses, and the estimated torque T of the load torque estimation unit 8 becomes the first torque T. At the time point P1 when the threshold value Ta of 2 is reached, the shut-off determination unit 10 outputs a second shut-off command to the motor control unit 12, and the motor control unit 12 stops the motor 1.
[0053]
【The invention's effect】
  As described above, the invention of claim 1 is a power-driven rotary tool used for tightening and tightening a plurality of types of screw members having different proper tightening torques. A drive unit that rotates the output shaft, a trigger switch that generates an operation signal according to the pull-in amount, a drive control unit that controls the rotation speed of the drive unit according to the operation signal input from the trigger switch, and an output shaft A load torque estimating unit for estimating the load torque;,negativeA load fluctuation amount detecting unit for detecting a fluctuation amount per predetermined time of the estimated value of the load torque estimating unit;The drive control unit issues a stop command to stop the drive unit for a predetermined stop time based on an estimated value of the load torque estimation unit and a detection result of the load fluctuation amount detection unit, in which appropriate tightening torques for a plurality of types of screw members are preset. A shut-off determination unit that outputs toWithThe shut-off determination unit compares the estimated value of the load torque estimation unit with a plurality of preset appropriate tightening torques, and drives a stop command each time the estimated value matches any of the appropriate tightening torques. In addition to outputting to the control unit, when the fluctuation amount detected by the load fluctuation amount detection unit is equal to or greater than a predetermined threshold, a stop command is output to the drive control unit,When a stop command is input from the shut-off determination unit, the drive control unitLoad torque estimation unitEstimated value isUnless the highest proper tightening torque among the plurality of proper tightening torques set in advance in the shut-off determination unit, the drive unit is stopped for the stop time regardless of the operation of the trigger switch, and until the stop time elapses. BetweenIf the trigger switch is not released during this time, rotate the drive again when the stop time has elapsed.LetWhen a stop command is inputIf the estimated value of the load torque estimation unit is the highest proper tightening torque among a plurality of proper tightening torques preset in the shut-off determination unit, the drive unit is stopped and the drive unit is restarted. Not performedThe shut-off determination unit outputs a stop command to the drive control unit when the load torque reaches an appropriate tightening torque of each screw member. When the stop command is input to the drive control unit, a predetermined command is output. Since the drive unit is stopped only for the stop time, the load torque can be set to the appropriate tightening torque at this point if the trigger switch is opened during this time. On the other hand, if the trigger switch is continuously pulled while the stop time elapses, the drive control unit restarts the rotation of the drive unit, and then is input from the shut-off determination unit when the load torque reaches the appropriate tightening torque. Since the drive unit is stopped by the stop command, the screw member can be tightened to the desired proper tightening torque by opening the trigger switch when the load torque reaches the desired proper tightening torque, and the drive unit The current tightening torque can be grasped by the number of times of stopping. Therefore, it is possible to efficiently perform the screw tightening operation of a plurality of screw members having different tightening torques without performing the tightening torque setting operation, and to set the tightening torque as in a conventional power-driven rotary tool. Since the torque setting device is unnecessary, there is an effect that the power driven rotary tool can be reduced in size and cost.
[0054]
  MoreoverWhen tightening a soft joint member such as a resin grommet, the tightening torque will be an appropriate value if the screw tightening operation is completed immediately after seating. Since the stop command is output first when the detected fluctuation amount exceeds a predetermined threshold, if the trigger switch is opened when the drive section is first stopped by the drive control section, the load torque fluctuation amount The driving portion can be stopped at the time when the pressure suddenly increases, that is, when the screw member is seated, and there is an effect that the soft joint member can be tightened with an appropriate tightening torque.
[0055]
  Claim2The invention of claim1'sIn the invention, the stop time is approximately 0.2 seconds or more and approximately 1 second or less, and the stop time is determined by the operator when the operator wants to finish the screw tightening operation when the load torque reaches a desired torque. Set the time so that the trigger switch can be released, and when the screw tightening operation is to be continued, the waiting time until the drive unit is restarted is not felt long. It is desirable that the stop time is approximately 0.2 seconds or more and approximately 1 second or less.
[0056]
  Claim3The invention of claim 1Or 2The stop time setting unit for changing the set value of the stop time is provided, and the stop time is set when the screw tightening operation is finished when the load torque reaches a desired torque. When the person can secure enough time to release the trigger switch, and when he wants to continue screw tightening, he will not feel long waiting time until the drive is restarted. It is desirable to set, and there is an effect that the stop time can be set to a desired time by the stop time setting unit.
[0057]
  Claim4The invention of claim1In this invention, when the fluctuation amount detected by the load fluctuation amount detection unit is not equal to or greater than the threshold value, the estimated value of the load torque estimation unit reaches a desired appropriate tightening torque and is driven from the shut-off determination unit. When a stop command is input to the control unit, the drive control unit stops the drive unit regardless of the operation signal of the trigger switch, and the trigger switch is released after the drive unit is stopped until the stop time elapses. If not, when the stop time has elapsed, the drive unit is rotated for a sufficiently short time that the operator can recognize the rotation of the drive unit, and then the drive unit is stopped. Depending on the design of the combination, the estimated value of the load torque estimation unit may reach the appropriate tightening torque of the screw member when the variation detected by the load variation detection unit does not exceed the threshold value. In such a case, the number of times that the drive unit stops before reaching the desired appropriate tightening torque is one less than the number of times expected by the operator, and the operator knows whether the screw tightening operation has been completed with the desired torque. The estimated value of the load torque estimation unit reaches the desired proper tightening torque when the variation detected by the load variation detection unit is not equal to or greater than the threshold value, and the shut-off determination unit When a stop command is input to the drive control unit, if the trigger switch is not released between the time when the drive unit is stopped and the predetermined stop time elapses, the drive control unit is Since it is stopped after rotating the drive unit for a predetermined time, it can be corrected by increasing the number of times the drive unit stops until the tightening torque reaches the desired appropriate tightening torque. The operator can be informed that the screw member has been tightened with the desired proper tightening torque, and in this case, the amount of rotation of the drive unit rotated by the drive control unit is sufficiently small. There will be no major deterioration.
[Brief description of the drawings]
[Figure 1]1 shows a basic configuration of an impact rotary tool according to the present invention.It is a block diagram.
FIG. 2 is a flowchart for explaining the operation described above.
FIG. 3 is a flowchart illustrating another operation of the above.
FIG. 4 Embodiment1It is a block diagram of the impact rotary tool of.
FIG. 5 is a flowchart for explaining the operation described above.
FIG. 6 is an embodiment.2It is a block diagram of the impact rotary tool of.
FIG. 73It is a flowchart explaining operation | movement of this impact rotary tool.
FIG. 8 is an explanatory diagram for explaining the relationship between the number of hits and torque.
FIG. 9 is a block diagram of a conventional impact rotary tool.
[Explanation of symbols]
  1 Motor
  6 Output shaft
  7 Trigger switch
  8 Load torque estimation unit
  10 Shut-off judgment part
  12 Motor controller

Claims (4)

In a power-driven rotary tool used for tightening and tightening a plurality of types of screw members having different proper tightening torques, an output shaft for tightening and tightening the screw members, a drive unit for rotating the output shaft, and a pull-in amount A trigger switch that generates an operation signal according to the control signal, a drive control unit that controls the rotational speed of the drive unit according to the operation signal input from the trigger switch, and a load torque that estimates a load torque applied to the output shaft an estimation unit, and a load variation amount detection unit which detects the amount of change per predetermined time of the previous estimate's rating load torque estimating unit, the proper tightening torque of the plurality of types of screw member is set in advance, the load torque estimate a shut-off decision section for outputting a stop command to the drive unit is stopped for a predetermined stop time to the drive control unit based on the estimated value and the load variation amount detection unit of the detection result of the part Includes, shut-off decision unit, for each of the comparing the level of the estimated value of the load torque estimating unit and the plurality of preset proper tightening torque, the estimated value matches any of the proper tightening torque The stop command is output to the drive control unit, and when the fluctuation amount detected by the load fluctuation amount detection unit is equal to or greater than a predetermined threshold, the stop command is output to the drive control unit. If the stop command from the shut-off decision section is input, the estimated value of the load torque estimating unit at the time of input of the stop command, among a plurality of preset proper tightening torque to the shut-off decision section if the highest proper tightening torque, the trigger switch the driving unit regardless of the operation of the trigger switch with stopping the stop time, until the stop time has elapsed If not open rotates the drive unit again when the stop time has elapsed, the estimated value of the load torque estimating unit at the time of input of the stop command, a plurality of appropriate tightening that has been preset in the shut-off determination unit If it is the highest appropriate tightening torque among the torques, the drive unit is stopped and the drive unit is not restarted . The power-driven rotary tool according to claim 1, wherein the stop time is approximately 0.2 seconds or more and approximately 1 second or less. The power-driven rotary tool according to claim 1 or 2, further comprising a stop time setting unit for changing the set value of the stop time. When the fluctuation amount detected by the load fluctuation amount detection unit is not equal to or greater than the threshold value, the estimated value of the load torque estimation unit reaches a desired appropriate tightening torque, and the shut-off determination unit When a stop command is input to the drive control unit, the drive control unit stops the drive unit regardless of the operation signal of the trigger switch, and until the stop time elapses after the drive unit is stopped. If the trigger switch is not opened in the meantime, when the stop time has elapsed, the drive unit is rotated only for a sufficiently short time that the operator can recognize the rotation of the drive unit, and then the drive unit is stopped. The power-driven rotary tool according to claim 1, wherein:

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