JP2004003585A - Locking bolt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple structured locking bolt with high productivity, excellent in tightening efficiency and repeated use, capable of preventing screwing force from being lowered, when external force is applied to a member to be tightened and a bolt or the like capable of semi-permanently maintaining high tightening force and remarkably increasing safety of a tightened part of the member to be tightened. <P>SOLUTION: The locking bolt is equipped with a bolt tip part coaxially formed with the bolt shaft part on the tip of the bolt shaft part, a main male screw part formed on the outer periphery of the bolt shaft part, an annular groove part formed annularly identical or deep of the bottom of thread of the main male screw part on the outer periphery of the bolt shaft part side of the bolt tip part and a sub male screw part, formed on the outer periphery of the bolt tip part, whose phase with respect to the female screw being displaced by 12° through 100°, preferably 24° through 90°, or further preferably 24° through 72°. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、ナット等の雄螺子に螺合して被締結部材を締結するとともに、被締結部材やナット等に振動等の外力がかかった際の螺着力、締結力の低下を防止できる緩み止めボルト及びその製造方法に関するものである。
【０００２】
【従来の技術】
従来から、自動車や航空機，電車等の輸送機器，各種の産業機械・機器，搬送パイプラインや電力等の送電装置，等における各種部分の締結には、ボルト・ナットが高い頻度で使用されており、また、ボルト・ナットは各種の締結部分の締結に用いられる機械要素として高い重要度を占めている。
しかしながら、従来から、ボルト・ナットで締結される被締結部材やナット等にかかる振動等の外力により雌螺子に螺合されたナット等が緩み、螺着力や締結力が低下して被締結部材の締結部が緩んだり外れたりするトラブルが後を絶たず、被締結部材の締結部の安全性の向上のため、被締結部材やナット等にかかる振動等の外力により緩みを防止するボルトやナットが望まれていた。
このため、近年、ナット等の雌螺子からボルトが緩むのを防止するために種々のボルトやナットが開発されており、特に、緩みを防止する緩み止めボルトとして特開昭５７−３７１１４号公報、特開平８−１０９９１５号公報、特開平９−２８０２３９号公報、特開平１１−３７１３０号公報、実開昭５７−８９０１６号、実開昭６１−６９５１７号公報等に種々のものが開示されている。これらは、螺子のフランクや座面に緩み防止のための回転止めを形成し変形して摩擦力を増加するもの等であり、一旦螺合した後に取り外すのが困難で繰り返し使用性に欠けるものであった。
【０００３】
繰り返し使用性を有する緩み止めボルトとしては、例えば、実開平４−３６１１６号公報（以下、イ号公報という）に「主ボルトと、前記主ボルトの端部の軸端に螺子部と等径かつ等ピッチの雄螺子が形成されて回転不能にかつ軸方向移動可能に配設された可変螺子と、前記主ボルト及び前記可変螺子の軸心部に挿通し前記主ボルトの螺子部に対して軸方向に正逆回転させることにより前記可変螺子を前記主ボルトの螺子部に対して軸方向に接離移動自在にする調整軸と、を備えた緩み止め付きボルト」が開示されている。
【０００４】
【発明が解決しようとする課題】
しかしながら上記従来の技術においては、以下のような課題を有していた。
（１）イ号公報に記載の技術は、部品点数が多く構成が複雑であるため製造に工数を要し生産性に欠けるという課題を有していた。
（２）部品点数が多く螺合する螺子部が多いため、螺子面のかじりや磨耗が発生し易く破損し易いという課題を有していた。
（３）調整軸を所定方向に回転させて可変螺子を軸方向の外側に押圧すると、可変螺子が主ボルトの螺子部から離間し、螺子部及び可変螺子のフランクが雌螺子のフランクを圧接して緩み止めを行うが、調整軸と可変螺子とを螺合する螺子部が緩み易く、これが緩んだ場合は螺子部及び可変螺子が雌螺子を圧接する力が弱まり、この結果、主ボルトが雌螺子から緩み易くなるという課題を有していた。
（４）締結作業を行う場合は、雌螺子に主ボルトを締結した後に調整軸を所定方向に回転して可変螺子を軸方向の外側に押圧しなければ緩み止めを行うことができず、作業工数を要し締結作業性に欠けるという課題を有していた。
（５）螺着時に緩み止め機構により非常に大きな力を必要とし、雌螺子の螺子山を破壊するという課題を有していた。
【０００５】
本発明は上記従来の課題を解決するもので、簡単な構造で生産性に優れるとともに、被締結部材やナット等に外力がかかった際の螺着力の低下を防止することができ、半永久的に高い締結力を維持することができ、被締結部材の締結部の安全性を著しく向上でき、また締結作業性にも優れ、さらに繰り返し使用性にも優れる緩み止めボルトを提供することを目的とする。
また、本発明は、簡便で作業性に優れるとともに生産性に優れ、さらに信頼性に優れる緩み止めボルトの製造方法を提供することを目的とする。
【０００６】
【課題を解決するための手段】
上記従来の課題を解決するために本発明の緩み止めボルト及びその製造方法は、以下の構成を有している。
【０００７】
本発明の請求項１に記載の緩み止めボルトは、雌螺子に螺合して被締結部材を締結する緩み止めボルトであって、ボルト軸部の先端部に前記ボルト軸部と同軸に形成されたボルト先端部と、前記ボルト軸部の外周に形成された主雄螺子部と、前記ボルト先端部の前記ボルト軸部側の外周に環状に形成された環状溝部と、前記主雄螺子部に対する位相が１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°変位して前記ボルト先端部の外周に形成された副雄螺子部と、を備えた構成を有している。
この構成により、以下のような作用が得られる。
（１）雌螺子に締め付けられた緩み止めボルトは、主雄螺子部に対する副雄螺子部の位相が所定量変位しているため、その締め付け力で発生する圧接力の主雄螺子部のフランクが雌螺子のフランクを圧接する方向と副雄螺子部のフランクが雌螺子のフランクを圧接する方向とが１８０°異なり相反している。このため、この圧接力と螺子のリード角等によって生じるトルクの方向が、主雄螺子部と副雄螺子部とでは正逆異なるので、ナットや被締結部材等に振動等の外力が加わり雌螺子から主雄螺子部が緩もうとする回転方向の力が加わると、副雄螺子部のフランクに発生するトルクが締め付け方向に作用するため、緩み止めボルトが雌螺子から緩むのを確実に防止でき半永久的に高い締結力を維持することができる。
（２）ボルト先端部の外周に、主雄螺子部に対する位相が１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に変位されて形成された副雄螺子部を備えているので、被締結部材を締結する際に緩み止めボルトを雌螺子に螺合することにより、副雄螺子部が主雄螺子部の方向に雌螺子を押圧する反力と主雄螺子部が副雄螺子部の方向に雌螺子を押圧する反力と、又は副雄螺子部が主雄螺子部と反対側の方向に雌螺子を押圧する反力と主雄螺子部が副雄螺子部と反対側の方向に雌螺子を押圧する反力とが生じ、これによって主雄螺子部及び副雄螺子部と雌螺子との間で大きな摩擦力を得ることができ、振動等により雌螺子から主雄螺子部等が緩み螺着力が低下するのを確実に防止できる。
（３）雌螺子に緩み止めボルトを締め付け締結力を加えると、緩み止めボルトの副雄螺子部が雌螺子によって変形されて弾性変形を生じ、弾性変形内でその反力により雌螺子に主雄螺子部と副雄螺子部をより強固に密着させて締結することができるので、緩み止めボルトと雌螺子の螺着力をより向上でき振動等の外力により緩み止めボルトが雌螺子から緩むのをより確実に防止できる。
（４）被締結部材と座面との間が磨耗して緩みが生じた場合であっても、副雄螺子部が雌螺子を主雄螺子部の方向に押圧する反力、又は副螺子部が雌螺子を主雄螺子部と反対側の方向に押圧する反力によって、緩み止めボルトが雌螺子から外れるのを防止することができ振動の激しい自動車や橋梁等に適用した場合でもボルトやナットが外れて落下するという落下事故を防止することができる。
（５）雌螺子に螺合された緩み止めボルトの副雄螺子部が雌螺子によって変形されて生じた弾性変形による反力により、雌螺子に主雄螺子部と副雄螺子部を強固に密着するので、弾性変形内で雌螺子と緩み止めボルトの雄螺子部の加工精度のばらつきによるガタツキを吸収することができ安定性に優れるとともに、変位量が小さいので、締結時に緩み止めボルトやナット等の螺子部に傷を付け難く、また弾性変形によって反力を安定して得ることができるので、同一の雌螺子であれば一旦螺合させた緩み止めボルトを取り外した後に再度螺着して繰り返し使用することができ、繰り返し使用性に優れる。
（６）主雄螺子部の谷底と同一若しくは深く形成された環状溝部を有しているので、雌螺子に主雄螺子部を螺着する際にスムーズに螺着することができるとともに圧縮若しくは引張変形を容易にすることができ、設計の自由度を増すとともに圧縮変形の際に主雄螺子部等が座屈するのを防止することができる。
【０００８】
ここで、ボルト先端部としては、ボルト軸部の先端部に、ボルト軸部と一体に形成又はボルト軸部に溶接等により固着されてボルト軸部と同軸に形成され、ボルト軸部の外周と同じ外径に形成された外周を有するものが用いられる。ボルト先端部の長さとしては、ボルト先端部の材質や螺着される雌螺子の材質等に応じて、主雄螺子部及び副雄螺子部が雌螺子と確実に螺着するための必要なかみあいが得られる長さで形成される。
ボルト先端部の反対側のボルト軸部には、六角ボルトのような六角柱状等の多角状，六角穴つきボルトのような頂面に六角穴等の穴部を有する円柱状，アイボルトのような輪状等に形成されたボルト頭を形成することができる。また、植込みボルト，控えボルト等のようにボルト頭を有さず螺子部が形成されたものや、基礎ボルト等のようにＬ形，Ｊ形等の形状に形成されたものも用いることができる。
【０００９】
主雄螺子部としては、緩み止めボルトが螺着される雌螺子に応じて、メートル螺子やインチ螺子等の三角螺子状や台形螺子状等で、かつ、雌螺子に応じたピッチで、ボルト軸部の外周に形成される。１条螺子の他、２条乃至複数条の多条螺子を形成することもできる。また、主雄螺子部の長さとしては、ボルト軸部やボルト先端部の材質、主雄螺子部が螺着される雌螺子の材質等に応じて、雌螺子との螺着に必要なかみあい長さが得られる長さで形成される。
【００１０】
環状溝部としては、ボルト軸部の軸心に対して略直交して若しくは斜交して形成され、ボルト先端部の外周に主雄螺子部の谷底と同一若しくは深い環状に形成され主雄螺子部と副雄螺子部とを分離するものが用いられる。特に、環状溝部が主雄螺子部の谷底よりも深く形成されボルト先端部を薄肉にしたものが好適に用いられる。弾性変形が容易だからである。環状溝部が主雄溝部の谷底と同一の深さで形成されると、環状溝部におけるボルト先端部の機械的強度が大きく伸びが生じ難いため、雌螺子や主雄螺子部の螺子山を潰し易くなる傾向がみられる。
なお、環状溝部がボルト軸部の軸心に対して斜交して形成される場合は、主雄螺子部のリード角と略平行する角度で形成することができる。これにより主雄螺子部と環状溝部で分離されて形成された副雄螺子部に、雌螺子がかみ込むことなく螺着できる。
【００１１】
副雄螺子部としては、環状溝部によって主雄螺子部と離間されて、ボルト先端部の外周に、主雄螺子部と同じピッチで、かつ、主雄螺子部に対する位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°変位させて形成される。
主雄螺子部に対する副雄螺子部の位相が、２４°より小さくなるにつれ雌螺子と緩み止めボルトの雄螺子部の加工精度のばらつきによるガタツキによって弾性変形量が少なくなり主雄螺子部と副雄螺子部によって雌螺子に得られる反力が小さく、緩み止めボルトと雌螺子の螺着力が低下する傾向がみられ、７２°〜９０°になると締結する前のトルクが大きく作業性が低下するとともに使用時に焼付きを生じ易くなる傾向がみられる。９０°より大きくなるにつれ、締結時に緩み止めボルトの螺子部が雌螺子にかみ込み易く締結に必要な力が大きくなり締結作業性に欠け、さらに締結時に緩み止めボルトやナット等の螺子部に傷を付け易くなり繰り返し使用性が低下する傾向がみられるため好ましくない。特に、副雄螺子部の螺合される雌螺子に対する位相が１２°より小さくなるか１００°より大きくなると、これらの傾向が著しいため、いずれも好ましくない。
なお、副雄螺子部の位相は、主雄螺子部側又は主雄螺子部と反対側のいずれに変位していてもよい。いずれの場合も、締結した際に生じる圧接力の主雄螺子部のフランクが雌螺子のフランクを圧接する方向と副雄螺子部のフランクが雌螺子のフランクを圧接する方向とを１８０°異ならせることができるからである。
副雄螺子部の形状や条数としては、主雄螺子部と同様のものが用いられる。
【００１２】
雌螺子としては、ナットの中心部や機械部品等に植設されたもの、板状や塊状等の構造物の所定部に螺設されたもの等を用いることができる。
【００１３】
本発明の請求項２に記載の発明は、請求項１に記載の緩み止めボルトであって、前記ボルト先端部が、前記ボルト先端部の軸中心に前記ボルト先端部の先端から少なくとも前記環状溝部まで形成された先端凹部を備えた構成を有している。この構成により、請求項１で得られる作用に加え、以下のような作用が得られる。
（１）先端凹部によって環状溝部の軸部を薄肉にし、弾力や曲げ応力等の機械的強度を最適にして螺子部に応じた反力を得ることができ、螺子部の損傷を防止するとともに緩み難くすることができる。
【００１４】
ここで、先端凹部としては、ボルトの径の大小若しくは環状溝部の幅の広狭に合わせてボルト先端部の軸中心にボルト先端部の先端から環状溝部の一部にかけて乃至は環状溝部を超えて形成されたものが用いられる。例えば、環状溝部の幅が広い場合は、先端凹部は環状溝部の幅の中央付近まででもよく、また該幅が狭い場合は該幅の少なくとも全幅にわたって先端凹部が穿設される。特に、先端凹部が環状溝部の全幅にわたって形成された場合は、薄肉にされた環状溝部の軸部を長く形成して弾性変形を容易にすることができるため好適に用いられる。
なお、環状溝部に対応する先端凹部の内径を大きくした大径凹部を形成することもできる。大径凹部を形成することによっても、環状溝部におけるボルト先端部の肉厚を所定の厚みに薄くすることができ、ボルト先端部の弾性変形を容易にすることができる。また、先端凹部や大径凹部は、ボルト先端部に形成された環状溝部を超えてボルト軸部の一部にも形成してよい。
【００１５】
本発明の請求項３に記載の発明は、請求項２に記載の緩み止めボルトであって、前記環状溝部における前記ボルト先端部が、軸方向に所定量だけ圧縮若しくは引張変形された弾性部を備えた構成を有している。
この構成により、請求項２で得られる作用に加え、以下のような作用が得られる。
（１）環状溝部におけるボルト先端部が圧縮若しくは引張変形された弾性部は弾性を有するので、螺合された雌螺子によって生じる副雄螺子部等の弾性変形に加え、螺合された雌螺子によって生じる弾性部の伸び若しくは収縮によって、雌螺子と緩み止めボルトの雄螺子部の加工精度のばらつきによるガタツキ等を吸収するとともに、弾性部の弾力によって雄螺子部に生じる反力をさらに大きくすることができ、緩み止めボルトが雌螺子から緩むのをより確実に防止できる。
（２）主雄螺子部と副雄螺子部とを同一ピッチかつ同一位相で形成した後、環状溝部を圧縮若しくは引張変形させることで主雄螺子部と副雄螺子部の位相を容易にずらすことができるので、製造が容易で生産性に優れる。
【００１６】
本発明の請求項４に記載の発明は、請求項３に記載の緩み止めボルトであって、前記環状溝部の軸方向の変形量αが、前記主雄螺子部のピッチの大きさをＰとしたとき、（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ、好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐ、より好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）である構成を有している。
この構成により、請求項３で得られる作用に加え、以下のような作用が得られる。
（１）環状溝部を変形量αで変形することにより、主雄螺子部に対する副雄螺子部の位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に確実に変位させることができるので、製品得率が高いとともに生産性に優れる。
（２）ｎの値を変えることにより環状溝部を所定の変形量にすることができ、環状溝部の変形が弾性限度以内であれば弾性部の弾力を変化させることができるので、弾性部の変位と反力との関係が安定的に得られ、得られる反力のばらつきが小さく安定性に優れる。
【００１７】
ここで、環状溝部の変形量αとしては、変形後の軸方向の環状溝部の長さＬ１を変形前の軸方向の環状溝部の長さＬ２から減じた長さ（Ｌ２−Ｌ１）が用いられ、主雄螺子部のピッチの大きさをＰとしたとき、（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ、好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐ、より好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）が好ましいとされる。環状溝部の変形量が、（ｎ＋１／１５）Ｐより小さくなる若しくは（ｎ−１／１５）Ｐより大きくなるにつれナット等の雌螺子と緩み止めボルトの雄螺子部の加工精度ばらつきによるガタツキを吸収し難く弾性変形量が少なくなり主雄螺子部と副雄螺子部によって雌螺子に得られる反力が小さく、緩み止めボルトと雌螺子の螺着力が低下する傾向がみられ、（ｎ＋１／５）Ｐ〜（ｎ＋１／４）Ｐになると締結前のトルクが大きく作業性が低下するとともに使用時に焼付き等が発生し易くなる傾向がみられる。（ｎ＋１／４）Ｐより大きくなる若しくは（ｎ−１／４）Ｐより小さくなるにつれ、締結時に緩み止めボルトの雄螺子部が雌螺子部にかみ込み易く締結に必要な力が大きくなり締結作業性に欠け、さらに締結時に緩み止めボルトや雌螺子に傷を付け易くなり繰り返し使用性が低下する傾向がみられるため好ましくない。特に、環状溝部の変形量が（ｎ＋１／３０）Ｐより小さくなる若しくは（ｎ−１／３０）Ｐより大きくなるか、（ｎ＋５／１８）Ｐより大きくなる若しくは（ｎ−５／１８）Ｐより小さくなると、これらの傾向が著しいため、いずれも好ましくない。
【００１８】
ｎは０以上の整数が用いられる。変形量α＝（ｎ＋１／３０）Ｐの場合を例にとって説明すると、α＝ｎＰ＋１／３０・Ｐであって、ｎが整数の場合に変形量ｎＰによっては位相のずれは発生せず、それを超えて変形された変形量１／３０・Ｐによって位相のずれを形成することができるからである。さらに、ｎは０〜４好ましくは１〜３が好適に用いられる。ｎが０のときは環状溝部の変形量が小さいため弾性部の弾力が大きくなり弾性部のわずかな変位により得られる反力の大きさが著しく異なりばらつきが大きく安定性が乏しくなる傾向がみられ、３より大きくなるにつれ環状溝部の変形量が大きく弾性部の弾力が小さくなり弾性部の変位によって得られる反力が小さくなる傾向がみられるため、いずれも好ましくない。特に、ｎが４より大きくなるとこの傾向が著しいため好ましくない。
【００１９】
圧縮変形前の環状溝部の軸方向の長さＬ２は、（ａ）主雄螺子部のピッチの大きさをＰ、環状溝部の底部の径をＡ、先端凹部の内径をＢとしたとき、Ｐ≦Ｌ２≦５Ｐ＋Ａ−Ｂ、又は、（ｂ）圧縮変形後の環状溝部の軸方向の長さをＬ１、弾性部の軸方向に対する変形角をθとしたとき、Ｌ２＝Ｌ１／ｃｏｓθ（但し、１０°≦θ≦７５°）が好適に用いられる。
これにより、以下のような作用が得られる。
（１）圧縮変形前の環状溝部の軸方向の長さが所定範囲にあるので環状溝部の座屈荷重を適量にし、圧縮変形させて副雄螺子部の位相を所定範囲に容易に変位させることができ、生産性に優れるとともに安定性に優れる。
（２）圧縮変形前の環状溝部の軸方向の長さが所定範囲にあるので、圧縮変形した場合に環状溝部内に弾性部を納めることができ、形成される弾性部の大きさ等の自由度に優れる。
（３）弾性部の変形角θが所定の範囲で形成されると、弾性部の最適な弾力が得られるとともに弾性部の変位と反力との関係が安定的に得られ、得られる反力のばらつきが小さく安定性に優れる。
【００２０】
ここで、圧縮変形前の環状溝部の軸方向の長さＬ２は、主雄螺子部のピッチの大きさをＰ、環状溝部の底部の径をＡ、先端凹部の内径をＢとしたとき、Ｐ≦Ｌ２≦５Ｐ＋Ａ−Ｂが好適に用いられる。圧縮変形前の環状溝部の軸方向の長さが主雄螺子部の１ピッチの大きさＰより小さくなるにつれ、環状溝部におけるボルト先端部の機械的強度が大きく環状溝部を圧縮変形させるために大きな荷重を要しプレス設備等の設備負荷が大きくなるとともに環状溝部以外の副雄螺子部等も変形し易く副雄螺子部等のピッチが小さくなり副雄螺子部がナット等の雌螺子にかみ込み易くなる傾向がみられ、さらに変形量αを大きくすることができず安定性を高め難い傾向がみられ、５Ｐ＋Ａ−Ｂより大きくなるにつれ座屈荷重が小さくなるとともに安定性が低下し主雄螺子部と副雄螺子部との軸がずれ易く雌螺子を副雄螺子部や主雄螺子部に螺着し難くなり、また副雄螺子部の機械的強度が小さく疲労し易いため長期信頼性が低下する傾向がみられるため好ましくない。
【００２１】
また、圧縮変形前の環状溝部の軸方向の長さＬ２は、圧縮変形後の環状溝部の軸方向の長さをＬ１、弾性部の軸方向に対する変形角をθとしたとき、Ｌ２＝Ｌ１／ｃｏｓθ（但し、１０°≦θ≦７５°）が好適に用いられる。弾性部の軸方向に対する変形角θが１０°より小さくなるにつれ、環状溝部の変形量が小さいため弾性部の弾力が大きくなり弾性部のわずかな変位により得られる反力の大きさが著しく異なりばらつきが大きく安定性が乏しくなる傾向がみられ、７５°より大きくなるにつれ環状溝部の変形量が大きく弾性部の弾力が小さくなり弾性部の変位によって得られる反力が小さくなる傾向がみられるため、いずれも好ましくない。
【００２２】
本発明の請求項５に記載の発明は、請求項１乃至４の内いずれか１に記載の緩み止めボルトであって、前記環状溝部の軸部の横断面積が、前記ボルト軸部の谷底における横断面積の５〜５０％である構成を有している。
この構成により、請求項１乃至４の内いずれか１で得られる作用に加え、以下のような作用が得られる。
（１）環状溝部の軸部の横断面積を規定することによって副雄螺子部が雌螺子に与える反力Ｑを所定範囲に設定できるので、（数１）によって表される締め付け前の空トルクＴｑを約１〜５０Ｎ・ｍ程度に抑えることができ、締結作業性に優れる。
【数１】

（２）環状溝部の軸部の肉厚を所定厚みに形成して機械的強度を所定範囲にできるので、ボルト先端部を変形させて副雄螺子部の位相を所定範囲に容易に変位させることができる。また、環状溝部の軸部に適量の伸びが生じ易く、雌螺子に螺着された際に軸部が伸びることにより雌螺子や副雄螺子部の螺子山を潰し難く装着性に優れる。
【００２３】
ここで、環状溝部の軸部の横断面積としては、先端凹部を有していない場合は環状溝部の外縁（底部の径）で囲まれた面積、先端凹部を有している場合は環状溝部の外縁（底部の径）で囲まれた面積から先端凹部の内縁（内径）で囲まれた面積を減じたものが用いられ、ボルト軸部の谷底における横断面積の５〜５０％が好ましいとされる。横断面積が５％より小さくなるにつれ座屈荷重が小さくなるとともに機械的強度が低下する傾向がみられ、５０％より大きくなるにつれ、軸部の座屈荷重が大きくなるとともに伸びや収縮が生じ難くなり空トルクが大きくなるとともにフランクを傷めたり焼付きを起こしたりする傾向がみられるため好ましくない。
【００２４】
なお、先端凹部が形成されたときのボルト先端部の副雄螺子部における肉厚（副雄螺子部の谷底から先端凹部の内周壁までの厚み）は、ボルト先端部の材質等に応じて、雌螺子との螺着に必要な機械的強度が得られる厚みで形成される。
【００２５】
本発明の請求項６に記載の緩み止めボルトの製造方法は、雌螺子に螺合して被締結部材を締結する緩み止めボルトの製造方法であって、ボルト軸部の軸中心に先端から穿設して先端凹部を形成する先端凹部形成工程と、前記ボルト軸部の先端側の所定部の外周に雄螺子の谷底と同一若しくはそれより深い環状溝部を形成する環状溝部形成工程と、前記ボルト軸部と略平行に所定荷重を所定時間印加して前記環状溝部形成工程で形成された前記環状溝部における前記ボルト軸部を、変形量αが前記雄螺子のピッチの大きさをＰとしたとき、（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐより好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）だけ変形させて弾性部を形成する弾性部形成工程と、を備えた構成を有している。
この構成により、以下の作用が得られる。
（１）先端凹部が形成された環状溝部におけるボルト軸部を変形させることで、位相のずれた主雄螺子部と副雄螺子部を容易に形成することができるので、製造が容易で生産性に優れる。
（２）環状溝部におけるボルト軸部が変形量αで変形されているので、主雄螺子部に対する副雄螺子部の位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に確実に変位させることができるので、信頼性に優れるとともに作業性に優れる。
【００２６】
ここで、環状溝部形成工程や先端凹部形成工程としては、旋盤やフライス等を用いた切削加工によって、雄螺子が形成されたボルト軸部の外周やボルト軸部の先端側に環状溝部や先端凹部を形成するものが用いられる。
先端凹部をボルト軸部の軸中心の先端から少なくとも環状溝部まで穿設して形成すれば、環状溝部形成工程に次いで先端凹部形成工程を行ってもよいし、先端凹部形成工程に次いで環状溝部形成工程を行ってもよい。
弾性部形成工程としては、加圧装置を用いてボルト軸部と略平行に所定荷重を所定時間印加するものが用いられる。荷重の印加は冷間で行うと好ましい。機械的強度が向上されるとともに高い寸法精度が得られるからである。
【００２７】
【発明の実施の形態】
以下、本発明の一実施の形態を、図面を参照しながら説明する。
（実施の形態１）
図１（ａ）は実施の形態１における緩み止めボルトの全体斜視図であり、図１（ｂ）は図１（ａ）の軸方向における要部断面端面図である。
図中、１は実施の形態１における緩み止めボルト、２は緩み止めボルト１のボルト軸部、３はボルト軸部２の先端部にボルト軸部２と一体で同軸に形成されたボルト先端部、４はボルト先端部３と反対側のボルト軸部２の端部に六角柱状に形成されたボルト頭、５は先端側のボルト軸部２の外周に１条乃至複数条の三角螺子や台形螺子、角螺子、鋸歯螺子状等（図は三角螺子を示す）に形成された主雄螺子部、６はボルト先端部３のボルト軸部２側の外周に主雄螺子部５の谷底と同一乃至はより深い環状に形成された環状溝部、７は環状溝部６におけるボルト先端部３が主雄螺子部５のピッチの大きさをＰとしたとき、変形量αが（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ、好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐ、より好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）だけ圧縮変形されてボルト先端部３の外周側に膨出し軸方向に圧縮された弾性部である。なお、弾性部７は引張変形させ肉厚を薄くして形成することもできる。８は環状溝部６を除くボルト先端部３の外周に主雄螺子部５と同一ピッチに形成された副雄螺子部、９はボルト先端部３の軸中心にボルト先端部３の先端から環状溝部６の幅の全部を超えてボルト軸部２の一部まで形成された先端凹部である。Ｌ１は圧縮変形して圧縮された環状溝部６（弾性部７）の軸方向の長さ、θは弾性部７の軸方向に対する変形角である。
【００２８】
以上のように構成された実施の形態１における緩み止めボルトの製造方法について、以下図面を用いて説明する。
図２（ａ）は実施の形態１における緩み止めボルトの環状溝部を圧縮変形する以前の状態を示す要部断面図であり、図２（ｂ）はボルトを加工しボルト先端部と先端凹部を形成したボルトの断面図である。
図２（ａ）において、５ａはボルト軸部２の外周に１条乃至複数条の三角螺子状に形成された雄螺子である。
図２（ｂ）において、６ａはボルト先端部３のボルト軸部２側の外周に環状に形成された環状溝部、７ａは環状溝部６ａの軸部、８ａは環状溝部６ａによって雄螺子５ａと分離されて形成された雄螺子である。Ａは環状溝部６ａの底部の径、Ｂは先端凹部９の内径、Ｌ２は圧縮変形前の環状溝部６ａの軸方向の長さ、雄螺子５ａ，８ａは螺合される雌螺子と同一ピッチかつ同一位相で形成されている。
実施の形態１では、圧縮変形前の環状溝部６ａの軸方向の長さＬ２が、Ｐ≦Ｌ２≦５Ｐ＋Ａ−Ｂ（但し、Ｐは雄螺子５ａ，８ａのピッチの大きさである）の大きさで形成されている。また、軸部７ａの横断面積π・（Ａ^２−Ｂ^２）／４が、ボルト軸部２の谷底（雄螺子５ａの谷底）における横断面積の５〜５０％に形成されている。さらに、弾性部７の変形角θ（図１（ｂ）参照）が１０°≦θ≦７５°でＬ２＝Ｌ１／ｃｏｓθの関係で形成されている。
【００２９】
まず、本体形成工程において、プレス成形等の塑性加工や切削加工等でボルト頭４と一体に形成され雄螺子５ａが螺設されたボルト軸部２を形成する（図２（ａ）参照）。
次いで、環状溝部形成工程において、ボルト軸部２の先端側の所定部の外周に雄螺子５ａの谷底よりも多少深い環状溝部６ａを形成し、ボルト先端部３を形成する。
次いで、先端凹部形成工程において、ボルト先端部３の軸中心にボルト先端部３の先端から環状溝部６ａの幅を超えてボルト軸部２の一部まで深く穿設して先端凹部９を形成する（図２（ｂ）参照）。
次いで、弾性部形成工程において、ボルト先端部３の先端とボルト頭４との間にボルト軸部２と略平行に環状溝部６におけるボルト先端部３の座屈荷重より大きな荷重を所定時間印加する。これにより、環状溝部６におけるボルト先端部３を、変形量αが（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ、好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐ、より好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、Ｐは雄螺子５ａ，８ａのピッチ、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）だけ圧縮変形させて弾性部７を形成する。この結果、雄螺子５ａが主雄螺子部５となり、雄螺子８ａが、主雄螺子部５に対する位相が１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に変位した副雄螺子部８となる（図１（ｂ）参照）。
【００３０】
なお、本実施の形態においては、プレス成形等の塑性加工や切削加工等でボルト頭４とボルト軸部２とを一体に形成しボルト軸部２に環状溝部６ａを形成する場合について説明したが、予め環状溝部６ａが形成されたボルト先端部３を形成しボルト軸部２の先端に抵抗溶接や摩擦溶接等の溶接や嵌合等によって固着してボルト先端部３をボルト軸部２と同軸に形成することもできる。この場合は、先端凹部９をボルト先端部３に予め形成しておいてもよいし、ボルト先端部３をボルト軸部２に固着した後に穿設して形成してもよい。
また、環状溝部形成工程において環状溝部６ａを形成した後、先端凹部形成工程において先端凹部９を形成する場合について説明したが、先端凹部形成工程において先端凹部９を形成した後、環状溝部形成工程において環状溝部６ａを形成する場合もある。この場合も同様の作用が得られる。
また、弾性部形成工程において、環状溝部６ａを捻じって変形量αだけ圧縮変形若しくは引張変形させる場合もある。この場合も同様の作用が得られる。
【００３１】
次に、実施の形態１における緩み止めボルトの変形例について、以下図面を用いて説明する。
図３は実施の形態１における緩み止めボルトの変形例を示す要部断面端面図である。
図中、１０は実施の形態１の変形例における緩み止めボルト、１１はボルト先端部３のボルト軸部２側の外周に主雄螺子部５の谷底と同じ深さでボルト軸部２の軸方向と略直交する環状に形成された環状溝部、１２はボルト先端部３の軸中心にボルト先端部３の先端から穿設形成された先端凹部、１２ａは環状溝部１１の内部のボルト先端部３に先端凹部１２の内径よりも大きな径で形成された先端凹部１２の大径凹部、１３は環状溝部１１におけるボルト先端部３が（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ、好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐ、より好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、Ｐは主雄螺子部５のピッチ、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）変形量αだけ圧縮変形されて大径凹部１２ａの内部に膨出した弾性部である。
この変形例のように、弾性部はボルト先端部の外周側に膨出するだけでなく、先端凹部の内部側に膨出させることもできる。なお、この場合は、弾性部形成工程において、弾性部が先端凹部の内部側に膨出するように外周側を拘束してやればよい。
【００３２】
次に、以上のように構成された実施の形態１における緩み止めボルトの使用時における動作について、以下図面を用いて説明する。
図４は実施の形態１における緩み止めボルトで被締結部材を締結した状態を示す要部断面図であり、図５は実施の形態１における緩み止めボルトで被締結部材を締結した際に弾性部に生じる反力と変位との関係を模式的に示す図であり、縦軸は弾性部に生じる反力を示し、横軸は弾性部の変形量を示す。
図４において、２０は板状や塊状等の構造物２０ａの所定部に螺設された雌螺子、２１は緩み止めボルト１で構造物２０ａに締結される被締結部材、２２は被締結部材２１に穿設され緩み止めボルト１が挿通されるボルト孔である。なお、図中Ｂは緩み止めボルト１を雌螺子２０に螺合した際に主雄螺子部５と雌螺子２０の螺合部分に加工精度ばらつき等によるガタツキによって形成される隙間（バックラッシ）、Ｂ´は副雄螺子部８と雌螺子２０の螺合部分に形成されるバックラッシを示す。バックラッシＢ，Ｂ´は各々反対方向に生じている。
【００３３】
被締結部材２１を緩み止めボルト１で締結する場合、被締結部材２１のボルト孔２２に緩み止めボルト１を挿通し、図４に示すように、緩み止めボルト１を雌螺子２０に螺合すると、弾性部７の軸方向の変形量αによって生じる雌螺子２０と副雄螺子部８との位相のずれに相当する変形量（図５の０Ｐ_２に等しいとする）からバックラッシＢ（又はＢ´）の軸方向の長さに相当する量（図５のＰ_１Ｐ_２に等しいとする）との差分の変形（図５に示す０Ｐ_１）が弾性部７に生じ、弾性部７の弾性変形に伴う反力（図５に示すＰ）が生じる。弾性部７に生じた反力（Ｐ）によって、副雄螺子部８，主雄螺子部５が雌螺子２０のフランクの正逆方向から押すことにより強固に締結される。
雌螺子２０に一旦螺合させた緩み止めボルト１を取り外せば、弾性部７に生じる反力は０になるとともに弾性部７の復元力によって変位も０になる。この取り外した緩み止めボルト１を雌螺子２０に再度螺着すれば、弾性部７に生じる反力（Ｐ）によって、副雄螺子部８と主雄螺子部５のフランクを雌螺子２０のフランクに強固に密着させて、何度でも繰り返し被締結部材２１を締結することができる。
【００３４】
以上のように、実施の形態１における緩み止めボルトは構成されているので、以下のような作用が得られる。
（１）雌螺子に締め付けられた緩み止めボルトは、主雄螺子部に対する副雄螺子部の位相が所定量変位しているため、その締め付け力で発生する圧接力の主雄螺子部のフランクが雌螺子のフランクを圧接する方向と副雄螺子部のフランクが雌螺子のフランクを圧接する方向とが１８０°異なり相反している。このため、この圧接力と螺子のリード角等によって生じるトルクの方向が、主雄螺子部と副雄螺子部とでは正逆異なるので、ナットや被締結部材等に振動等の外力が加わり雌螺子から主雄螺子部が緩もうとする回転方向の力が加わると、副雄螺子部のフランクに発生するトルクが締め付け方向に作用するため、緩み止めボルトが雌螺子から緩むのを確実に防止でき半永久的に高い締結力を維持することができる。
（２）ボルト先端部の外周に、主雄螺子部に対する位相が１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に変位されて形成された副雄螺子部を備えているので、被締結部材を締結する際に緩み止めボルトを雌螺子に螺合することにより、副雄螺子部が主雄螺子部の方向に雌螺子を押圧する反力と主雄螺子部が副雄螺子部の方向に雌螺子を押圧する反力と、又は副雄螺子部が主雄螺子部と反対側の方向に雌螺子を押圧する反力と主雄螺子部が副雄螺子部と反対側の方向に雌螺子を押圧する反力とが生じ、これによって主雄螺子部及び副雄螺子部と雌螺子との間で大きな摩擦力を得ることができ、振動等により雌螺子から主雄螺子部等が緩み螺着力が低下するのを確実に防止できる。また、変位量が従来と比べて小さいので、螺着時に少ない抵抗で容易に螺着できる。
（３）雌螺子に緩み止めボルトを締め付け締結力を加えると、緩み止めボルトの副雄螺子部が雌螺子の締結によって変形されて弾性変形を生じ、弾性変形内でその反力により雌螺子に主雄螺子部と副雄螺子部をより強固に密着させて締結することができるので、緩み止めボルトと雌螺子の螺着力をより向上でき振動等の外力により緩み止めボルトが雌螺子から緩むのをより確実に防止できる。
（４）被締結部材と座面との間が磨耗して緩みが生じた場合であっても、副雄螺子部が雌螺子を主雄螺子部の方向に押圧する反力、又は副螺子部が雌螺子を主雄螺子部と反対側の方向に押圧する反力によって、緩み止めボルトが雌螺子から外れるのを防止することができ自動車や電車等の振動が激しい車両や橋梁等でのボルトやナットの落下事故を防止することができる。
（５）雌螺子に螺合された緩み止めボルトの副雄螺子部が雌螺子によって変形されて生じた弾性変形による反力により、雌螺子に主雄螺子部と副雄螺子部を強固に密着するので、雌螺子と緩み止めボルトの雄螺子部の加工精度のばらつきによるガタツキを吸収することができ安定性に優れるとともに、位相の変位量が小さいので、締結時に緩み止めボルトやナット等の螺子部に傷を付け難く、また弾性変形によって反力を安定して得ることができるので、同一の雌螺子であれば一旦螺合させた緩み止めボルトを取り外した後に再度螺着して繰り返し使用することができ、繰り返し使用性に優れる。
（６）主雄螺子部の谷底と同一若しくは深く形成された環状溝部を有しているので、雌螺子に主雄螺子部を螺着する際にスムーズに螺着することができるとともにボルト先端部を薄肉にして圧縮変形を容易にすることができ、圧縮変形の際に主雄螺子部等が座屈するのを防止することができる。
（７）環状溝部におけるボルト先端部が圧縮変形された弾性部は弾性を有するので、螺合された雌螺子によって生じる副雄螺子部等の弾性変形に加え、螺合された雌螺子によって生じる弾性部の伸びによって、雌螺子と緩み止めボルトの雄螺子部の加工精度のばらつきによるガタツキ等を吸収するとともに、弾性部が有する弾力によって発生する応力により、生じる反力をさらに大きくすることができ、緩み止めボルトが雌螺子から緩むのをより確実に防止できる。
（８）主雄螺子部と副雄螺子部とを同一ピッチかつ同一位相で形成した後、環状溝部を圧縮変形させることで主雄螺子部と副雄螺子部の位相を容易にずらすことができるので、製造が容易で生産性に優れる。
（９）先端凹部を備えているので、環状溝部が形成されたボルト先端部を薄肉にすることができ、ボルト先端部の圧縮変形が容易で生産性に優れる。
（１０）環状溝部を変形量αだけ圧縮することにより、主雄螺子部に対する副雄螺子部の位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に確実に変位させることができ、変形量が適量なので締結時に螺子部に傷を付けたり使用時に焼付きが生じ難く繰り返し使用性に優れ、さらに螺子部のピッチや角度等にバラツキを生じても締結時にフランク同士の圧接が十分得られ安定性に優れる。また、製品得率が高く生産性に優れる。
（１１）ｎの値を変えることにより環状溝部を所定の変形量にすることができ、環状溝部の変形が弾性限度内であれば弾性部の弾力を変化させることができるので、弾性部の変位と反力との関係が安定的に得られ、得られる反力のばらつきが小さく安定性に優れる。
（１２）圧縮変形前の環状溝部の軸方向の長さＬ２がＰ≦Ｌ２≦５Ｐ＋Ａ−Ｂの所定範囲にあるので、環状溝部の座屈荷重を適量にし、圧縮変形させて副雄螺子部の位相を所定範囲に容易に変位させることができ、生産性に優れるとともに安定性に優れる。
（１３）圧縮変形前の環状溝部の軸方向の長さＬ２が所定範囲にあるので、圧縮変形した場合に環状溝部内に弾性部を納めることができ、形成される弾性部の大きさ等の自由度に優れる。
（１４）環状溝部の軸部の横断面積を規定することによって副雄螺子部が雌螺子に与える反力を所定範囲に設定できるので、雌螺子や雄螺子部を破損することなしに緩み止めを行うことができる。
（１５）環状溝部の軸部の肉厚を所定厚みに形成して機械的強度を所定範囲にできるので、ボルト先端部を圧縮変形する際には副雄螺子部の位相を所定範囲に容易に変位させることができる。また、環状溝部の軸部に適量の伸びが生じ易く、雌螺子に螺着された際に軸部が伸びることにより雌螺子や副雄螺子部の螺子山を潰し難く装着性に優れる。
（１６）弾性部の変形角θが所定の範囲で形成されているので、弾性部の最適な弾力が得られるとともに弾性部の変位と反力との関係が安定的に得られ、得られる反力のばらつきが小さく安定性に優れる。
（１７）ＪＩＳやＡＳＭＥ、ＤＩＮ等で規格化されたボルトを加工するので、汎用性に優れる。
【００３５】
なお、実施の形態１においては、環状溝部６を変形量α（ｎは０以上の整数）だけ圧縮変形した場合について説明したが、環状溝部６に引張荷重を印加して、変形量α（ｎが０の場合）が−５／１８・Ｐ≦α≦−１／３０・Ｐ好ましくは−１／４・Ｐ≦α≦−１／１５・Ｐより好ましくは−１／５・Ｐ≦α≦−１／１５・Ｐの範囲になるようにすることもできる。この場合も同様の作用が得られる。
【００３６】
（実施の形態２）
図６は実施の形態２における緩み止めボルトで被締結部材を締結した状態を示す要部断面図であり、図７は実施の形態２における緩み止めボルトで被締結部材を締結した際に主雄螺子部と副雄螺子部にかかる応力と歪みとの関係を模式的に示す図であり、縦軸は主雄螺子部と副雄螺子部にかかる応力を示し、横軸は主雄螺子部と副雄螺子部の歪み量を示す。なお、実施の形態１で説明したものと同様のものは、同じ符号を付して説明を省略する。
図中、３０は実施の形態２における緩み止めボルト、３１はボルト先端部３のボルト軸部２側の外周に主雄螺子部５の谷底よりも多少大きな深さでボルト軸部２の軸方向と略直交する環状に形成された環状溝部、３１ａは環状溝部３１の軸部、３２は環状溝部３１からボルト先端部３の先端に向けてボルト先端部３の外周に主雄螺子部５と同一ピッチ、かつ、主雄螺子部５に対する位相が、１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に変位されて旋盤等で螺刻若しくは転造して形成された副雄螺子部である。
【００３７】
実施の形態２における緩み止めボルトが実施の形態１と異なる点は、環状溝部を圧縮変形させて副雄螺子部の位相を変位させるのではなく、旋盤等で螺刻等して主雄螺子部５に対する副雄螺子部３２の位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に変位させる点である。
【００３８】
被締結部材２１を緩み止めボルト３０で締結する場合も、実施の形態１で説明したのと同様に図６に示すように、被締結部材２１のボルト孔２２に緩み止めボルト３０を挿通し、緩み止めボルト３０を雌螺子２０に螺合すると、主雄螺子部５と副雄螺子部３２とに弾性限度（図７に示すＵ点）より大きく極限強さ（図７に示すＭ点）より小さな応力（図７に示すＳ点）が生じる。これにより、副雄螺子部３２に永久歪み（図７に示す０Ｓ_１）が生じて変形し、雌螺子２０と主雄螺子部５，副雄螺子部３２の加工精度ばらつき等によるバックラッシＢ，Ｂ´が主雄螺子部５と副雄螺子部３２で正逆反対方向に生じる。さらに、弾性変形（図７に示すＳ_１Ｓ_２）によって生じる反力によって、副雄螺子部３２，主雄螺子部５が雌螺子２０のフランクの正逆方向から押すことにより強固に締結される。
雌螺子２０に一旦螺合させた緩み止めボルト３０は、雌螺子２０に応じて副雄螺子部３２に永久歪み（図７に示す０Ｓ_１）が生じ変形しており、雌螺子２０から取り外した後もこの変形が維持される。この緩み止めボルト３０を雌螺子２０に再度螺着した場合も、副雄螺子部３２の弾性変形（図７に示すＳ_１Ｓ_２）によって生じる反力が雌螺子２０に働き、何度でも強固に締結することができる。
【００３９】
以上のように、実施の形態２における緩み止めボルトは構成されているので、実施の形態１に記載の作用に加え、以下のような作用が得られる。
（１）旋盤等で螺刻して副雄螺子部の主雄螺子部に対する位相（螺合される雌螺子に対する位相）を変位させるので、圧縮変形させるためのプレス設備等を要さず設備負荷を少なくすることができる。
（２）環状溝部及び先端凹部を形成することによってボルト先端部を薄肉にすることができるので、弾力や曲げ応力等の機械的強度を最適にして螺子部に応じた反力を得ることができ、螺子部の損傷を防止するとともに緩み難くすることができる。
【００４０】
なお、実施の形態１における緩み止めボルトは、実施の形態２で説明した弾性変形（図７に示すＳ_１Ｓ_２）によって生じる反力と、実施の形態１における緩み止めボルトにおいて弾性部７に生じる反力（Ｐ）と、を加えた反力が発生しているため、実施の形態２と比較してより大きな反力が得られ大きな螺着力が得られる。
【００４１】
【発明の効果】
以上のように、本発明の緩み止めボルトによれば、以下のような有利な効果が得られる。
請求項１に記載の発明によれば、
（１）雌螺子に締め付けられた緩み止めボルトは、主雄螺子部に対する副雄螺子部の位相が所定量変位しているため、その締め付け力で発生する圧接力の主雄螺子部のフランクが雌螺子のフランクを圧接する方向と副雄螺子部のフランクが雌螺子のフランクを圧接する方向とが１８０°異なり相反している。このため、この圧接力と螺子のリード角等によって生じるトルクの方向が、主雄螺子部と副雄螺子部とでは正逆異なるので、ナットや被締結部材等に振動等の外力が加わり雌螺子から主雄螺子部が緩もうとする回転方向の力が加わると、副雄螺子部のフランクに発生するトルクが締め付け方向に作用するため、緩み止めボルトが雌螺子から緩むのを確実に防止でき半永久的に高い締結力を維持することができる緩み止めボルトを提供することができる。
（２）ボルト先端部の外周に、主雄螺子部に対する位相が１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に変位されて形成された副雄螺子部を備えているので、被締結部材を締結する際に緩み止めボルトを雌螺子に螺合することにより、副雄螺子部が主雄螺子部の方向に雌螺子を押圧する反力と主雄螺子部が副雄螺子部の方向に雌螺子を押圧する反力と、又は副雄螺子部が主雄螺子部と反対側の方向に雌螺子を押圧する反力と主雄螺子部が副雄螺子部と反対側の方向に雌螺子を押圧する反力とが生じ、これによって主雄螺子部及び副雄螺子部と雌螺子との間で大きな摩擦力を得ることができ、振動等により雌螺子から主雄螺子部等が緩み螺着力が低下するのを確実に防止できる緩み止めボルトを提供することができる。
（３）雌螺子に緩み止めボルトを締め付け締結力を加えると、緩み止めボルトの副雄螺子部が雌螺子によって変形されて弾性変形を生じ、弾性変形内でその反力により雌螺子に主雄螺子部と副雄螺子部をより強固に密着させて締結することができるので、緩み止めボルトと雌螺子の螺着力をより向上でき振動等の外力により緩み止めボルトが雌螺子から緩むのをより確実に防止できる緩み止めボルトを提供することができる。
（４）被締結部材と座面との間が磨耗して緩みが生じた場合であっても、副雄螺子部が雌螺子を主雄螺子部の方向に押圧する反力、又は副雄螺子部が雌螺子を主雄螺子部と反対側の方向に押圧する反力によって、緩み止めボルトが雌螺子から外れるのを防止することができ振動の激しい自動車や橋梁等に適用した場合でもボルトやナットが外れて落下するという落下事故を防止することができる緩み止めボルトを提供することができる。
（５）雌螺子に螺合された緩み止めボルトの副雄螺子部が雌螺子によって変形されて生じた弾性変形による反力により、雌螺子に主雄螺子部と副雄螺子部を強固に密着するので、弾性変形内で雌螺子と緩み止めボルトの雄螺子部の加工精度のばらつきによるガタツキを吸収することができ安定性に優れるとともに、位相の変位量が小さいので、締結時に緩み止めボルトやナット等の螺子部に傷を付け難く、また弾性変形によって反力を安定して得ることができるので、同一の雌螺子であれば一旦螺合させた緩み止めボルトを取り外した後に再度螺着して繰り返し使用することができ、繰り返し使用性に優れた緩み止めボルトを提供することができる。
（６）主雄螺子部の谷底と同一若しくは深く形成された環状溝部を有しているので、雌螺子に主雄螺子部を螺着する際にスムーズに螺着することができるとともに圧縮若しくは引張変形を容易にすることができ、設計の自由度を増すとともに圧縮変形の際に主雄螺子部等が座屈するのを防止することができる緩み止めボルトを提供することができる緩み止めボルトを提供することができる。
【００４２】
請求項２に記載の発明によれば、請求項１の効果に加え、
（１）先端凹部によって環状溝部の軸部を薄肉にし、弾力や曲げ応力等の機械的強度を最適にして螺子部に応じた反力を得ることができ、螺子部の損傷を防止するとともに緩み難くすることができる緩み止めボルトを提供することができる。
【００４３】
請求項３に記載の発明によれば、請求項２の効果に加え、
（１）環状溝部におけるボルト先端部が圧縮若しくは引張変形された弾性部は弾性を有するので、螺合された雌螺子によって生じる副雄螺子部等の弾性変形に加え、螺合された雌螺子によって生じる弾性部の伸び若しくは収縮によって、雌螺子と緩み止めボルトの雄螺子部の加工精度ばらつきによるガタツキ等を吸収するとともに、弾性部の弾力に応じて発生する応力によって、生じる反力をさらに大きくすることができ、緩み止めボルトが雌螺子から緩むのをより確実に防止できる緩み止めボルトを提供することができる。
（２）主雄螺子部と副雄螺子部とを同一ピッチかつ同一位相で形成した後、環状溝部を圧縮若しくは引張変形させることで主雄螺子部と副雄螺子部の位相を容易にずらすことができるので、製造が容易で生産性に優れた緩み止めボルトを提供することができる。
【００４４】
請求項４に記載の発明によれば、請求項３の効果に加え、
（１）環状溝部を変形量αで変形することにより、主雄螺子部に対する副雄螺子部の位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に確実に変位させることができるので、製品得率が高いとともに生産性に優れた緩み止めボルトを提供することができる。
（２）ｎの値を変えることにより環状溝部を所定の変形量にすることができ、環状溝部の変形が弾性限度以内であれば弾性部の弾力を変化させることができるので、弾性部の変位と反力との関係が安定的に得られ、得られる反力のばらつきが小さく安定性に優れた緩み止めボルトを提供することができる。
【００４５】
請求項５に記載の発明によれば、請求項１乃至４の内いずれか１の効果に加え、
（１）環状溝部の軸部の横断面積を規定することによって副雄螺子部が雌螺子に与える反力Ｑを所定範囲に設定できるので、締結前の空トルクＴｑを約１〜５０Ｎ・ｍ程度に抑えることができ、締結作業性に優れた緩み止めボルトを提供することができる。
（２）環状溝部の軸部の肉厚を所定厚みに形成して機械的強度を所定範囲にできるので、ボルト先端部を変形させて副雄螺子部の位相を所定範囲に容易に変位させることができる。また、環状溝部の軸部に適量の伸びが生じ易く、雌螺子に螺着された際に軸部が伸びることにより雌螺子や副雄螺子部の螺子山を潰し難く装着性に優れた緩み止めボルトを提供することができる。
【００４６】
請求項６に記載の発明によれば、
（１）先端凹部が形成された環状溝部におけるボルト軸部を圧縮変形させることで、位相のずれた主雄螺子部と副雄螺子部を容易に形成することができるので、製造が容易で生産性に優れた緩み止めボルトの製造方法を提供することができる。
（２）環状溝部におけるボルト軸部が変形量αで変形されているので、主雄螺子部に対する副雄螺子部の位相を１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°に確実に変位させることができるので、信頼性に優れるとともに作業性に優れた緩み止めボルトの製造方法を提供することができる。
【図面の簡単な説明】
【図１】（ａ）実施の形態１における緩み止めボルトの全体斜視図
（ｂ）図１（ａ）の軸方向における要部断面端面図
【図２】（ａ）実施の形態１における緩み止めボルトの環状溝部を圧縮変形する以前の状態を示す要部断面図
（ｂ）ボルトを加工しボルト先端部と先端凹部を形成したボルトの断面図
【図３】実施の形態１における緩み止めボルトの変形例を示す要部断面端面図
【図４】実施の形態１における緩み止めボルトで被締結部材を締結した状態を示す要部断面図
【図５】実施の形態１における緩み止めボルトで被締結部材を締結した際に弾性部に生じる力と変位との関係を模式的に示す図
【図６】実施の形態２における緩み止めボルトで被締結部材を締結した状態を示す要部断面図
【図７】実施の形態２における緩み止めボルトで被締結部材を締結した際に主雄螺子部と副雄螺子部にかかる応力と歪みとの関係を模式的に示す図
【符号の説明】
１　緩み止めボルト
２　ボルト軸部
３　ボルト先端部
４　ボルト頭
５　主雄螺子部
５ａ　雄螺子
６，６ａ　環状溝部
７　弾性部
７ａ　軸部
８　副雄螺子部
８ａ　雄螺子
９　先端凹部
１０　緩み止めボルト
１１　環状溝部
１２　先端凹部
１２ａ　大径凹部
１３　弾性部
２０　雌螺子
２０ａ　構造物
２１　被締結部材
２２　ボルト孔
３０　緩み止めボルト
３１　環状溝部
３１ａ　軸部
３２　副雄螺子部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a locking device that can fasten a member to be fastened by being screwed into a male screw such as a nut, and prevent a decrease in screwing force and fastening force when an external force such as vibration is applied to the member or nut. The present invention relates to a bolt and a method for manufacturing the bolt.
[0002]
[Prior art]
2. Description of the Related Art Bolts and nuts have been used frequently for fastening various parts in transportation equipment such as automobiles, airplanes and trains, various industrial machines and equipment, transfer pipelines and power transmission devices such as electric power, and the like. Bolts and nuts are of great importance as mechanical elements used for fastening various fastening parts.
However, conventionally, the nut or the like screwed into the female screw is loosened by external force such as vibration applied to the member to be fastened or the nut or the like fastened by the bolt / nut, and the screwing force or the fastening force is reduced and the strength of the member to be fastened is reduced. The bolts and nuts that prevent loosening due to external forces such as vibrations applied to the members to be fastened or nuts are used to improve the safety of the fastening parts of the members to be fastened in order to improve the safety of the fastening parts of the members to be fastened. Was desired.
For this reason, in recent years, various bolts and nuts have been developed to prevent bolts from being loosened from female threads such as nuts. In particular, JP-A-57-37114 discloses a locking bolt for preventing loosening. Various types are disclosed in JP-A-8-109915, JP-A-9-280239, JP-A-11-37130, JP-A-57-89016, JP-A-61-69517, and the like. . These are designed to increase the frictional force by forming a rotation stopper on the flank or seat surface of the screw to prevent loosening, and to increase the frictional force. there were.
[0003]
For example, Japanese Utility Model Laid-Open Publication No. 4-36116 (hereinafter referred to as “A”) discloses a locking bolt having repetitive usability “a main bolt and a screw portion at the end of the main bolt having the same diameter as a screw portion. A variable screw formed with a male screw having an equal pitch and arranged so as to be non-rotatable and axially movable, and inserted through the main bolt and the axial center of the variable screw to rotate with respect to the screw part of the main bolt; An adjustable shaft that rotates the variable screw in the axial direction with respect to the screw portion of the main bolt by rotating the variable screw forward and backward in a direction.
[0004]
[Problems to be solved by the invention]
However, the above-described conventional technology has the following problems.
(1) The technology described in Japanese Patent Publication No. A has a problem that the number of parts is large and the configuration is complicated, so that man-hours are required for manufacturing and productivity is lacking.
(2) Since the number of parts is large and the number of screw portions to be screwed is large, there is a problem that the screw surface is liable to be galled or worn and easily damaged.
(3) When the adjusting screw is rotated in a predetermined direction to press the variable screw outward in the axial direction, the variable screw is separated from the screw portion of the main bolt, and the flank of the screw portion and the variable screw presses the flank of the female screw. Although the screw portion for screwing the adjusting shaft and the variable screw is easily loosened, when the screw is loosened, the force with which the screw portion and the variable screw press the female screw is weakened. There was a problem that the screws could easily be loosened.
(4) In the case of performing the fastening work, if the main screw is fastened to the female screw and then the adjusting shaft is rotated in a predetermined direction and the variable screw is not pushed outward in the axial direction, the loosening cannot be performed. There was a problem that it required man-hours and lacked fastening workability.
(5) A very large force is required by the loosening prevention mechanism at the time of screwing, and there is a problem that the screw thread of the female screw is broken.
[0005]
The present invention solves the above-mentioned conventional problems, and is excellent in productivity with a simple structure, and can prevent a decrease in screwing force when external force is applied to a member to be fastened or a nut, and can be semi-permanently. An object of the present invention is to provide a locking bolt that can maintain a high fastening force, can significantly improve the safety of a fastening portion of a member to be fastened, is excellent in fastening workability, and is excellent in repeated use. .
Another object of the present invention is to provide a method of manufacturing a locking bolt that is simple, has excellent workability, is excellent in productivity, and has excellent reliability.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, a locking bolt according to the present invention and a method for manufacturing the same have the following configurations.
[0007]
A locking bolt according to claim 1 of the present invention is a locking bolt that is screwed into a female screw to fasten a member to be fastened, and is formed coaxially with the bolt shaft at the tip of the bolt shaft. A bolt tip portion, a main male screw portion formed on the outer periphery of the bolt shaft portion, an annular groove portion formed annularly on the outer periphery of the bolt tip portion on the bolt shaft portion side, and a main male screw portion. And a secondary male screw portion formed on the outer periphery of the tip end of the bolt with a phase of 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °.
With this configuration, the following operation is obtained.
(1) Since the phase of the sub male screw portion with respect to the main male screw portion is displaced by a predetermined amount, the flank of the main male screw portion of the press contact force generated by the tightening force of the locking screw tightened to the female screw portion is changed. The direction in which the flank of the female screw is pressed and the direction in which the flank of the sub male screw portion presses the flank of the female screw differ by 180 ° and are opposite to each other. For this reason, the direction of the torque generated by the pressing force and the lead angle of the screw is different between the main male screw part and the sub male screw part, and external force such as vibration is applied to the nut and the member to be fastened. When a force in the rotational direction is applied to the main male screw part to loosen, the torque generated in the flank of the sub male screw part acts in the tightening direction, so that the locking bolt can be reliably prevented from loosening from the female screw. A high fastening force can be maintained semi-permanently.
(2) Since the outer peripheral portion of the bolt tip is provided with a sub-male screw portion formed so that the phase with respect to the main male screw portion is displaced by 12 to 100 °, preferably 24 to 90 °, and more preferably 24 to 72 °. By fastening the locking bolt to the female screw when fastening the member to be fastened, the secondary male screw part presses the female screw in the direction of the main male screw part, and the main male screw part becomes the secondary male screw. The reaction force that presses the female screw in the direction of the part, or the reaction force that the secondary male screw part presses the female screw in the direction opposite to the main male screw part, and the main male screw part that is opposite to the secondary male screw part A reaction force that presses the female screw in the direction is generated, whereby a large frictional force can be obtained between the main male screw part and the sub male screw part and the female screw, and the female screw is moved from the female screw to the main male screw part by vibration or the like. , Etc., and the screwing force can be reliably prevented from lowering.
(3) When a tightening force is applied to the female screw by tightening the locking screw, the secondary male screw portion of the locking bolt is deformed by the female screw to generate elastic deformation. Since the screw part and the auxiliary male screw part can be more firmly adhered and fastened, the screwing force between the locking bolt and the female screw can be further improved, and the locking bolt can be more loosened from the female screw due to external force such as vibration. It can be reliably prevented.
(4) Even if the part between the member to be fastened and the bearing surface is worn and loosened, the secondary male screw part presses the female screw in the direction of the main male screw part, or the secondary screw part. Can prevent the locking bolt from coming off from the female screw by the reaction force that presses the female screw in the direction opposite to the main male screw part, and even when applied to automobiles and bridges with severe vibration, Can be prevented from falling off.
(5) The main male screw part and the sub male screw part are firmly adhered to the female screw by the reaction force due to the elastic deformation generated by the secondary male screw part of the locking bolt screwed into the female screw being deformed by the female screw. As a result, it is possible to absorb rattling due to variations in processing accuracy of the female screw and the male screw part of the locking screw within elastic deformation, and it is excellent in stability, and since the displacement is small, the locking bolt and nut etc. It is difficult to damage the screw part of the screw, and it is possible to stably obtain the reaction force by elastic deformation, so if the same female screw is used, remove the once screwed locking bolt and then screw it again and repeat It can be used and is excellent in repeated use.
(6) Since the main male screw portion has an annular groove formed to be the same as or deeper than the bottom of the main male screw portion, the main male screw portion can be smoothly screwed into the female screw while being compressed or pulled. Deformation can be facilitated, design flexibility can be increased, and buckling of the main male screw portion and the like during compression deformation can be prevented.
[0008]
Here, as the bolt tip, the tip of the bolt shaft is formed integrally with the bolt shaft or fixed to the bolt shaft by welding or the like, and is formed coaxially with the bolt shaft. Those having an outer periphery formed with the same outer diameter are used. The length of the bolt tip is determined according to the material of the bolt tip, the material of the female screw to be screwed, and the like, so that the main male screw part and the sub male screw part can be securely screwed to the female screw. It is formed with a length that allows engagement.
The bolt shaft on the opposite side of the bolt tip has a polygonal shape such as a hexagonal bolt like a hexagonal bolt, a cylindrical shape with a hexagonal hole on the top surface like a hexagonal bolt, and an eyebolt. A bolt head formed in a ring shape or the like can be formed. Further, a bolt having no screw head and having a threaded portion, such as a stud bolt, a retaining bolt, or the like, or a bolt having a L-shaped or J-shaped shape, such as a base bolt, can be used. .
[0009]
The main male screw portion may have a triangular screw shape such as a metric screw or an inch screw, a trapezoidal screw shape, or the like, depending on the female screw to which the locking bolt is screwed, and a pitch corresponding to the female screw. Formed on the outer periphery of the part. In addition to a single screw, two or more multi-thread screws can be formed. The length of the main male screw portion is determined according to the material of the bolt shaft portion and the bolt tip portion, the material of the female screw to which the main male screw portion is screwed, and the like. The length is formed with the length obtained.
[0010]
The annular groove portion is formed substantially orthogonally or obliquely to the axis of the bolt shaft portion, and is formed in the outer periphery of the tip end portion of the bolt in the same or deep annular shape as the bottom of the main male screw portion. One that separates the secondary male screw part from the secondary male screw part is used. In particular, the one in which the annular groove portion is formed deeper than the root of the main male screw portion and the tip end portion of the bolt is thin is preferably used. This is because elastic deformation is easy. If the annular groove is formed at the same depth as the bottom of the main male groove, the mechanical strength of the bolt tip in the annular groove is so large that it is difficult to elongate, so that the female screw and the screw thread of the main male screw are easily crushed. There is a tendency.
When the annular groove is formed obliquely with respect to the axis of the bolt shaft, it can be formed at an angle substantially parallel to the lead angle of the main male screw. As a result, the female screw can be screwed into the sub male screw portion formed separately from the main male screw portion and the annular groove portion without biting.
[0011]
The secondary male screw portion is separated from the main male screw portion by an annular groove, and has the same pitch as the main male screw portion on the outer periphery of the bolt tip, and has a phase of 12 to 100 ° with respect to the main male screw portion, preferably. It is formed with a displacement of 24 to 90 °, more preferably 24 to 72 °.
As the phase of the sub male screw portion with respect to the main male screw portion becomes smaller than 24 °, the amount of elastic deformation is reduced due to rattling due to the variation in processing accuracy of the female screw portion and the male screw portion of the locking screw, and the main male screw portion and the sub male screw are reduced. The reaction force obtained on the female screw by the screw portion is small, and there is a tendency that the screwing force between the locking bolt and the female screw is reduced. When the angle becomes 72 ° to 90 °, the torque before fastening is large, and the workability is reduced. There is a tendency for seizure to occur easily during use. As the angle becomes larger than 90 °, the screw portion of the locking bolt is easily entangled into the female screw at the time of fastening, and the force required for fastening is increased, and the workability of fastening is lacking. Further, the screw portion of the locking bolt or nut is damaged at the time of fastening. This is not preferable because it tends to give a tendency to deteriorate the reusability. In particular, when the phase of the sub male screw portion with respect to the female screw to be screwed is smaller than 12 ° or larger than 100 °, these tendencies are remarkable, and neither is preferable.
Note that the phase of the sub male screw portion may be displaced to either the main male screw portion side or the side opposite to the main male screw portion. In any case, the direction in which the flank of the main male screw portion presses the flank of the female screw and the direction in which the flank of the sub male screw portion presses the flank of the female screw in the pressing force generated at the time of fastening differ by 180 °. Because you can do it.
The shape and the number of the sub male screw portions are the same as those of the main male screw portion.
[0012]
As the female screw, a screw threaded at a predetermined portion of a plate-like or lump-shaped structure or the like can be used.
[0013]
The invention according to claim 2 of the present invention is the locking bolt according to claim 1, wherein the bolt tip is at least the annular groove from the tip of the bolt tip about the axis of the bolt tip. It has a configuration provided with a tip concave portion formed up to this point. With this configuration, the following operation is obtained in addition to the operation obtained in the first aspect.
(1) The shaft portion of the annular groove portion is made thinner by the concave portion at the tip, and the reaction force corresponding to the screw portion can be obtained by optimizing the mechanical strength such as elasticity and bending stress, thereby preventing the screw portion from being damaged and loosening. It can be difficult.
[0014]
Here, the tip recess is formed from the tip of the bolt tip to a part of the annular groove or beyond the annular groove at the center of the bolt axis in accordance with the diameter of the bolt or the width of the annular groove. What was done is used. For example, when the width of the annular groove portion is wide, the distal end recess may be located near the center of the width of the annular groove portion, and when the width is small, the distal end recess is perforated over at least the entire width of the width. In particular, when the tip concave portion is formed over the entire width of the annular groove portion, it is preferably used because the shaft portion of the thin annular groove portion can be formed long to facilitate elastic deformation.
It is also possible to form a large-diameter concave portion in which the inner diameter of the distal concave portion corresponding to the annular groove portion is increased. By forming the large-diameter recess, the thickness of the bolt tip in the annular groove can be reduced to a predetermined thickness, and the elastic deformation of the bolt tip can be facilitated. Further, the tip concave portion and the large-diameter concave portion may be formed in a part of the bolt shaft beyond the annular groove formed in the bolt distal end.
[0015]
The invention according to claim 3 of the present invention is the locking bolt according to claim 2, wherein the bolt tip in the annular groove has an elastic portion compressed or tensile-deformed by a predetermined amount in the axial direction. It has a configuration provided.
With this configuration, the following operation is obtained in addition to the operation obtained in the second aspect.
(1) Since the elastic portion of the annular groove portion where the bolt tip is compressed or tensilely deformed has elasticity, in addition to the elastic deformation of the sub-male screw portion and the like generated by the screwed female screw, the screwed female screw is used. Due to the extension or shrinkage of the elastic portion, it is possible to absorb backlash and the like due to variation in processing accuracy of the female screw and the male screw portion of the locking bolt, and to further increase the reaction force generated in the male screw portion by the elasticity of the elastic portion. It is possible to more reliably prevent the locking bolt from loosening from the female screw.
(2) After the main male screw part and the sub male screw part are formed with the same pitch and the same phase, the phase of the main male screw part and the sub male screw part is easily shifted by compressing or stretching the annular groove part. Therefore, the production is easy and the productivity is excellent.
[0016]
The invention according to claim 4 of the present invention is the locking bolt according to claim 3, wherein the amount of deformation α in the axial direction of the annular groove portion is P with the pitch of the main male screw portion being P. Then, (n + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15) P ≦ α ≦ (n + ／) P, more preferably (n + 1/15) P ≦ α ≦ ( (n + ／) P or (n−5 / 18) P ≦ α ≦ (n−1 / 30) P, preferably (n − ／) P ≦ α ≦ (n−1 / 15) P Is (n−1 / 5) P ≦ α ≦ (n−1 / 15) P (where n is an integer of 0 or more; α is positive in the compression direction and negative in the tensile direction). have.
According to this configuration, the following operation is obtained in addition to the operation obtained in the third aspect.
(1) By deforming the annular groove portion by the deformation amount α, the phase of the sub male screw portion with respect to the main male screw portion is reliably displaced to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °. Therefore, the product yield is high and the productivity is excellent.
(2) By changing the value of n, the annular groove can be deformed to a predetermined amount. If the deformation of the annular groove is within the elastic limit, the elasticity of the elastic part can be changed. And the reaction force can be stably obtained, and the obtained reaction force has a small variation and is excellent in stability.
[0017]
Here, as the deformation amount α of the annular groove portion, a length (L2-L1) obtained by subtracting the length L1 of the axial annular groove portion after the deformation from the length L2 of the axial annular groove portion before the deformation is used. When the size of the pitch of the main male screw portion is P, (n + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15) P ≦ α ≦ (n + ／) P, More preferably (n + 1/15) P ≦ α ≦ (n +＋ １) P or (n−5 / 18) P ≦ α ≦ (n−1 / 30) P, preferably (n−−１) P .Ltoreq..alpha..ltoreq. (N-1 / 15) P, more preferably (n-1 / 5) P.ltoreq..ltoreq..ltoreq. (N-1 / 15) P (where n is an integer of 0 or more. Α is the compression direction). Positive and negative in the tensile direction) are preferred. As the amount of deformation of the annular groove becomes smaller than (n + 1/15) P or becomes larger than (n-1 / 15) P, rattling due to variation in processing accuracy of the female screw of the nut or the like and the male screw of the locking bolt is absorbed. And the amount of elastic deformation is reduced, the reaction force obtained on the female screw by the main male screw portion and the sub male screw portion is small, and the screwing force between the locking bolt and the female screw tends to decrease (n + ／). When P to (n + ／) P, the torque before fastening is large, the workability is reduced, and seizure or the like tends to occur during use. As the value becomes larger than (n + ／) P or becomes smaller than (n−1 / 4) P, the male screw portion of the locking bolt easily bites into the female screw portion at the time of fastening, and the force required for fastening increases, and fastening work is performed. It is not preferable because it lacks in ease of use, and tends to damage the locking bolt and female screw at the time of fastening, which tends to reduce the usability repeatedly. In particular, the amount of deformation of the annular groove is smaller than (n + 1/30) P, larger than (n-1 / 30) P, larger than (n + 5/18) P, or larger than (n-5 / 18) P. When the size is small, these tendencies are remarkable, and neither is preferable.
[0018]
n is an integer of 0 or more. Taking the case where the deformation amount α = (n + 1/30) P as an example, α = nP + 1/30 · P, and when n is an integer, no phase shift occurs depending on the deformation amount nP. This is because a phase shift can be formed by the deformation amount 1/30 · P deformed beyond. Further, n is preferably 0 to 4, preferably 1 to 3. When n is 0, the amount of deformation of the annular groove is small, so that the elasticity of the elastic portion becomes large, and the magnitude of the reaction force obtained by a slight displacement of the elastic portion is remarkably different. Since the deformation amount of the annular groove becomes larger and the elasticity of the elastic portion becomes smaller as the ratio becomes larger than 3, the reaction force obtained by the displacement of the elastic portion tends to become smaller. In particular, when n is larger than 4, this tendency is remarkable, which is not preferable.
[0019]
The axial length L2 of the annular groove before compression deformation is as follows: (a) P is the size of the pitch of the main male screw portion, A is the diameter of the bottom of the annular groove, and B is the inner diameter of the recess at the tip. ≦ L2 ≦ 5P + AB, or (b) When the axial length of the annular groove after compression deformation is L1 and the deformation angle of the elastic portion with respect to the axial direction is θ, L2 = L1 / cos θ (10 (° ≦ θ ≦ 75 °) is preferably used.
Thereby, the following operation is obtained.
(1) Since the axial length of the annular groove before compression deformation is within a predetermined range, the buckling load of the annular groove is adjusted to an appropriate amount, and the phase of the secondary male screw portion is easily displaced to a predetermined range by compression deformation. It is excellent in productivity and stability.
(2) Since the axial length of the annular groove before compression deformation is within a predetermined range, the elastic portion can be accommodated in the annular groove when compressed and deformed, and the size of the elastic portion to be formed can be freely set. Excellent degree.
(3) When the deformation angle θ of the elastic portion is formed in a predetermined range, the optimum elasticity of the elastic portion is obtained, and the relationship between the displacement of the elastic portion and the reaction force is stably obtained, and the obtained reaction force And the stability is excellent.
[0020]
Here, the axial length L2 of the annular groove portion before the compression deformation is P when the magnitude of the pitch of the main male screw portion is P, the diameter of the bottom portion of the annular groove portion is A, and the inner diameter of the concave portion at the tip is B. ≦ L2 ≦ 5P + AB is preferably used. As the axial length of the annular groove portion before the compression deformation becomes smaller than the size P of one pitch of the main male screw portion, the mechanical strength of the bolt tip portion in the annular groove portion is large, and is large in order to compressively deform the annular groove portion. A load is required, and the equipment load of press equipment etc. increases, and the secondary male screw parts other than the annular groove part are also easily deformed, the pitch of the secondary male screw part etc. becomes small, and the secondary male screw part gets stuck in the female screw such as nut. It tends to be difficult to increase the deformation amount α, and it is difficult to increase the stability. As the ratio becomes larger than 5P + AB, the buckling load decreases and the stability decreases. The axis of the female part and the auxiliary male screw part is easily displaced, making it difficult to screw the female screw to the auxiliary male screw part and the main male screw part. The mechanical strength of the auxiliary male screw part is small and it is easy to fatigue, so long-term reliability is improved. Tend to decrease Unfavorable.
[0021]
The axial length L2 of the annular groove before the compression deformation is L2 = L1 / L2, where L1 is the axial length of the annular groove after the compression deformation and θ is the deformation angle of the elastic portion with respect to the axial direction. cos θ (however, 10 ° ≦ θ ≦ 75 °) is preferably used. As the deformation angle θ of the elastic portion with respect to the axial direction becomes smaller than 10 °, the elasticity of the elastic portion increases due to the small amount of deformation of the annular groove portion, and the magnitude of the reaction force obtained by a slight displacement of the elastic portion is significantly different and varies. Tends to be poor in stability, and as the angle becomes larger than 75 °, the amount of deformation of the annular groove increases, the elasticity of the elastic portion decreases, and the reaction force obtained by the displacement of the elastic portion tends to decrease. Neither is preferred.
[0022]
The invention according to claim 5 of the present invention is the locking bolt according to any one of claims 1 to 4, wherein the cross-sectional area of the shaft of the annular groove is at the bottom of the bolt shaft. It has a configuration that is 5 to 50% of the cross-sectional area.
With this configuration, the following operation is obtained in addition to the operation obtained in any one of the first to fourth aspects.
(1) By defining the cross-sectional area of the shaft portion of the annular groove portion, the reaction force Q applied to the female screw by the sub-male screw portion can be set within a predetermined range. Therefore, the idle torque Tq before tightening represented by (Equation 1) Can be suppressed to about 1 to 50 N · m, and the fastening workability is excellent.
(Equation 1)

(2) Since the thickness of the shaft portion of the annular groove portion is formed to a predetermined thickness and the mechanical strength can be set in a predetermined range, the tip of the bolt is deformed to easily displace the phase of the secondary male screw portion to a predetermined range. Can be. In addition, an appropriate amount of elongation is likely to occur in the shaft portion of the annular groove portion, and when the screw portion is screwed to the female screw, the shaft portion expands, so that the screw threads of the female screw and the sub-male screw portion are hardly crushed, and the mounting property is excellent.
[0023]
Here, as the cross-sectional area of the shaft portion of the annular groove portion, the area surrounded by the outer edge (diameter of the bottom portion) of the annular groove portion when not having the tip concave portion, and the area surrounded by the annular groove portion when having the tip concave portion. A product obtained by subtracting the area surrounded by the inner edge (inner diameter) of the tip concave portion from the area surrounded by the outer edge (diameter at the bottom) is used, and it is considered that 5 to 50% of the cross-sectional area at the bottom of the bolt shaft is preferable. . As the cross-sectional area becomes smaller than 5%, the buckling load becomes smaller and the mechanical strength tends to decrease. As the cross-sectional area becomes larger than 50%, the buckling load of the shaft becomes larger and elongation and shrinkage hardly occur. It is not preferable because the air torque increases and the flank tends to be damaged or seizure occurs.
[0024]
The thickness (thickness from the valley bottom of the sub male screw portion to the inner peripheral wall of the tip concave portion) of the sub male screw portion at the tip of the bolt when the tip concave portion is formed depends on the material of the bolt tip portion and the like. It is formed with a thickness that provides the mechanical strength required for screwing with the female screw.
[0025]
A method for manufacturing a locking bolt according to claim 6 of the present invention is a method for manufacturing a locking bolt for fastening a member to be fastened by screwing into a female screw. A step of forming a leading end recess to form a leading end recess; an annular groove forming step of forming an annular groove at a depth equal to or deeper than the root of a male screw on the outer periphery of a predetermined portion on the distal end side of the bolt shaft; When a predetermined load is applied substantially in parallel with the shaft portion for a predetermined time and the bolt shaft portion in the annular groove portion formed in the annular groove portion forming step is deformed by α, the magnitude of the pitch of the male screw is P. , (N + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15) P ≦ α ≦ (n + ／) P, more preferably (n + 1/15) P ≦ α ≦ (n + ／) P or (n−5 / 18) P ≦ α ≦ (n−1 / 30) P preferably (n-−１) P ≦ α ≦ (n−1 / 15) P, more preferably (n − ／) P ≦ α ≦ (n−1 / 15) P (where n Is an integer greater than or equal to 0. α is a compression direction is positive, and a tensile direction is negative.).
With this configuration, the following operation is obtained.
(1) By deforming the bolt shaft portion in the annular groove portion having the recess formed at the tip, the main male screw portion and the sub male screw portion having a phase shift can be easily formed, so that manufacturing is easy and productivity is high. Excellent.
(2) Since the bolt shaft portion in the annular groove portion is deformed by the deformation amount α, the phase of the sub male screw portion with respect to the main male screw portion is set to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °. Since it can be reliably displaced, it is excellent in reliability and workability.
[0026]
Here, as the annular groove portion forming step and the tip concave portion forming step, the cutting process using a lathe, a milling cutter, or the like includes an annular groove portion and a distal concave portion on the outer periphery of the bolt shaft portion on which the male screw is formed or on the distal end side of the bolt shaft portion. Is used.
If the tip recess is formed by drilling from the tip of the shaft center of the bolt shaft portion to at least the annular groove, the tip recess forming step may be performed subsequent to the annular groove forming step, or the annular groove forming may be performed subsequent to the tip recess forming step. A step may be performed.
In the step of forming the elastic portion, a process of applying a predetermined load for a predetermined time substantially in parallel with the bolt shaft portion using a pressing device is used. It is preferable to apply the load in a cold state. This is because mechanical strength is improved and high dimensional accuracy is obtained.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1A is an overall perspective view of a locking bolt according to Embodiment 1, and FIG. 1B is a sectional end view of a main part in an axial direction of FIG. 1A.
In the figure, reference numeral 1 denotes a locking bolt according to the first embodiment, reference numeral 2 denotes a bolt shaft portion of the locking bolt 1, and reference numeral 3 denotes a bolt tip formed integrally with the bolt shaft 2 at the tip of the bolt shaft 2. Reference numeral 4 denotes a hexagonal column-shaped bolt head at the end of the bolt shaft 2 opposite to the bolt tip 3, and 5 denotes one or more triangular screws or trapezoids on the outer periphery of the bolt shaft 2 at the tip. A main male screw portion formed in a screw shape, a square screw shape, a saw tooth screw shape or the like (the figure shows a triangular screw shape), and 6 is the same as the bottom of the main male screw portion 5 on the outer periphery of the bolt tip portion 3 on the bolt shaft portion 2 side. Or an annular groove portion formed in a deeper annular shape, and when the bolt tip 3 in the annular groove portion 6 has a pitch P of the main male screw portion 5 as P, the deformation amount α is (n + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15) P ≦ α ≦ (n + ／) P, more preferably Or (n + 1/15) P ≦ α ≦ (n + ／) P, or (n−5 / 18) P ≦ α ≦ (n−1 / 30) P, preferably (n − ／) P ≦ α ≦ (n−1 / 15) P, more preferably (n−1 / 5) P ≦ α ≦ (n−1 / 15) P (where n is an integer of 0 or more. α is a positive compression direction) , The tensile direction is assumed to be negative.) The elastic portion is compressed and deformed only, and swells to the outer peripheral side of the bolt tip portion 3 and is compressed in the axial direction. In addition, the elastic part 7 can also be formed by performing a tensile deformation to reduce the thickness. Reference numeral 8 denotes a sub-male screw portion formed at the same pitch as the main male screw portion 5 on the outer periphery of the bolt tip portion 3 except for the annular groove portion 6, and 9 designates an annular groove from the tip of the bolt tip portion 3 around the axis of the bolt tip portion 3. 6 is a tip concave portion formed over a part of the bolt shaft portion 2 over the entire width of 6. L1 is the axial length of the annular groove 6 (elastic portion 7) compressed and deformed, and θ is the deformation angle of the elastic portion 7 with respect to the axial direction.
[0028]
The method of manufacturing the locking bolt according to Embodiment 1 configured as described above will be described below with reference to the drawings.
FIG. 2A is a sectional view of a main part showing a state before the annular groove portion of the locking bolt according to the first embodiment is compressed and deformed, and FIG. It is sectional drawing of the formed bolt.
In FIG. 2A, reference numeral 5a denotes a male screw formed in the shape of one or more triangular screws on the outer periphery of the bolt shaft 2.
In FIG. 2B, reference numeral 6a denotes an annular groove formed annularly on the outer periphery of the bolt tip 2 on the side of the bolt shaft 2, reference numeral 7a denotes a shaft of the annular groove 6a, and reference numeral 8a denotes a male screw 5a separated by the annular groove 6a. This is a male screw formed. A is the diameter of the bottom of the annular groove 6a, B is the inner diameter of the tip recess 9, L2 is the axial length of the annular groove 6a before compressive deformation, and the male screws 5a and 8a have the same pitch as the female screw to be screwed. They are formed in the same phase.
In the first embodiment, the axial length L2 of the annular groove 6a before compression deformation is P ≦ L2 ≦ 5P + AB (where P is the pitch of the male screws 5a, 8a). It is formed with. Also, the cross-sectional area π · (A ² -B ² ) / 4 are formed at 5 to 50% of the cross-sectional area at the bottom of the bolt shaft portion 2 (the bottom of the male screw 5a). Further, the deformation angle θ (see FIG. 1B) of the elastic portion 7 is formed in a relationship of L2 = L1 / cos θ when 10 ° ≦ θ ≦ 75 °.
[0029]
First, in a main body forming step, a bolt shaft portion 2 integrally formed with the bolt head 4 and having a male screw 5a screwed therein is formed by plastic working such as press forming or cutting work (see FIG. 2A).
Next, in an annular groove portion forming step, an annular groove portion 6a slightly deeper than the root of the male screw 5a is formed on the outer periphery of a predetermined portion on the tip side of the bolt shaft portion 2, and the bolt tip portion 3 is formed.
Next, in a tip concave portion forming step, a tip concave portion 9 is formed by drilling deeply from the distal end of the bolt distal end portion 3 to the part of the bolt shaft portion 2 beyond the width of the annular groove 6a around the axis of the bolt distal end portion 3. (See FIG. 2 (b)).
Next, in the elastic portion forming step, a load larger than the buckling load of the bolt tip 3 in the annular groove 6 is applied between the tip of the bolt tip 3 and the bolt head 4 substantially in parallel with the bolt shaft 2 for a predetermined time. . Thereby, the deformation amount α of the bolt tip 3 in the annular groove 6 is (n + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15) P ≦ α ≦ (n + ／) P , More preferably (n + 1/15) P ≦ α ≦ (n + ／) P, or (n−5 / 18) P ≦ α ≦ (n−1 / 30) P, preferably (n− ／). P ≦ α ≦ (n−1 / 15) P, more preferably (n−1 / 5) P ≦ α ≦ (n−1 / 15) P (where P is the pitch of the male screws 5a and 8a, and n is 0) The elastic portion 7 is formed by compressing and deforming by α by a positive integer in the compression direction and a negative in the tensile direction. As a result, the male screw 5a becomes the main male screw part 5, and the male screw 8a is the sub male screw whose phase with respect to the main male screw part 5 is displaced to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °. The part 8 (see FIG. 1B).
[0030]
In the present embodiment, a case has been described in which the bolt head 4 and the bolt shaft 2 are integrally formed by plastic working such as press forming or cutting, and the annular groove 6a is formed in the bolt shaft 2. A bolt tip 3 having an annular groove 6a formed in advance is formed and fixed to the tip of the bolt shaft 2 by welding or fitting such as resistance welding or friction welding so that the bolt tip 3 is coaxial with the bolt shaft 2. Can also be formed. In this case, the tip concave portion 9 may be formed in the bolt tip portion 3 in advance, or may be formed by fixing the bolt tip portion 3 to the bolt shaft portion 2 and then piercing it.
Further, the case where the tip recess 9 is formed in the tip recess forming step after the formation of the annular groove 6a in the annular groove forming step has been described. The annular groove 6a may be formed. In this case, the same operation can be obtained.
In addition, in the elastic portion forming step, the annular groove 6a may be twisted and compressed or stretched by the deformation amount α in some cases. In this case, the same operation can be obtained.
[0031]
Next, a modified example of the locking bolt according to Embodiment 1 will be described below with reference to the drawings.
FIG. 3 is a cross-sectional end view of a main part showing a modification of the locking bolt according to the first embodiment.
In the drawing, reference numeral 10 denotes a locking bolt according to a modification of the first embodiment, and 11 denotes a shaft of the bolt shaft 2 at the same depth as the root of the main male screw 5 on the outer periphery of the bolt tip 2 on the bolt shaft 2 side. An annular groove portion formed in an annular shape substantially perpendicular to the direction, 12 is a tip concave portion formed by drilling from the tip of the bolt tip portion 3 around the axis of the bolt tip portion 3, and 12a is a bolt tip portion 3 inside the annular groove portion 11. The large-diameter concave portion 13 of the distal concave portion 12 formed with a diameter larger than the inner diameter of the distal concave portion 12 is preferably (n + 1/30) P ≦ α ≦ (n + 5/18) P when the bolt distal end 3 in the annular groove portion 11 is formed. Is (n + 1/15) P ≦ α ≦ (n + ／) P, more preferably (n + 1/15) P ≦ α ≦ (n + ／) P, or (n−5 / 18) P ≦ α ≦ ( n−1 / 30) P, preferably (n − ／) P ≦ α ≦ (n−1 / 15) P More preferably, (n-1 / 5) P ≦ α ≦ (n−1 / 15) P (where P is the pitch of the main male screw portion 5 and n is an integer of 0 or more. Α is a positive compression direction. The tensile direction is assumed to be negative.) The elastic portion is compressed and deformed by the deformation amount α and swells inside the large-diameter concave portion 12a.
As in this modification, the elastic portion can not only bulge to the outer peripheral side of the bolt tip but also bulge to the inner side of the tip recess. In this case, in the elastic portion forming step, the outer peripheral side may be restrained so that the elastic portion swells inside the distal end concave portion.
[0032]
Next, the operation when the locking bolt according to the first embodiment configured as described above is used will be described with reference to the drawings.
FIG. 4 is a cross-sectional view of a main part showing a state where the member to be fastened is locked by the locking bolt according to the first embodiment. FIG. 5 is an elastic portion when the member to be fastened is locked by the locking bolt according to the first embodiment. FIG. 4 is a diagram schematically showing a relationship between a reaction force and a displacement generated in the elastic member. The vertical axis indicates a reaction force generated in the elastic portion, and the horizontal axis indicates a deformation amount of the elastic portion.
In FIG. 4, reference numeral 20 denotes a female screw threaded at a predetermined portion of a plate-like or block-like structure 20 a, reference numeral 21 denotes a member to be fastened to the structure 20 a by the locking bolt 1, and reference numeral 22 denotes a member 21 to be fastened. And a bolt hole through which the locking bolt 1 is inserted. In the figure, B is a gap (backlash) formed by rattling due to processing accuracy variation or the like at the threaded portion between the main male screw part 5 and the female screw 20 when the locking bolt 1 is screwed into the female screw 20. ′ Indicates a backlash formed at a threaded portion between the sub male screw portion 8 and the female screw 20. Backlashes B and B 'are generated in opposite directions.
[0033]
When the member 21 is fastened with the locking bolt 1, the locking bolt 1 is inserted into the bolt hole 22 of the member 21, and the locking bolt 1 is screwed into the female screw 20 as shown in FIG. 4. 5, a deformation amount corresponding to a phase shift between the female screw 20 and the sub-male screw portion 8 caused by an axial deformation amount α of the elastic portion 7 (0P in FIG. 5). ₂ To the amount corresponding to the axial length of the backlash B (or B ′) (P in FIG. 5). ₁ P ₂ ) And the difference (0P shown in FIG. 5) ₁ ) Is generated in the elastic portion 7, and a reaction force (P shown in FIG. 5) is generated due to the elastic deformation of the elastic portion 7. Due to the reaction force (P) generated in the elastic portion 7, the auxiliary male screw portion 8 and the main male screw portion 5 are firmly fastened by pushing the female screw 20 in the forward and reverse directions of the flank.
If the locking bolt 1 once screwed to the female screw 20 is removed, the reaction force generated in the elastic part 7 becomes zero and the displacement becomes zero due to the restoring force of the elastic part 7. If the removed locking bolt 1 is screwed again to the female screw 20, the flank of the auxiliary male screw portion 8 and the main male screw portion 5 is changed to the flank of the female screw 20 by the reaction force (P) generated in the elastic portion 7. By firmly adhering, the member to be fastened 21 can be fastened many times.
[0034]
As described above, since the locking bolt according to Embodiment 1 is configured, the following operation is obtained.
(1) Since the phase of the sub male screw portion with respect to the main male screw portion is displaced by a predetermined amount, the flank of the main male screw portion of the press contact force generated by the tightening force of the locking screw tightened to the female screw portion is changed. The direction in which the flank of the female screw is pressed and the direction in which the flank of the sub male screw portion presses the flank of the female screw differ by 180 ° and are opposite to each other. For this reason, the direction of the torque generated by the pressing force and the lead angle of the screw is different between the main male screw part and the sub male screw part, and external force such as vibration is applied to the nut and the member to be fastened. When a force in the rotational direction is applied to the main male screw part to loosen, the torque generated in the flank of the sub male screw part acts in the tightening direction, so that the locking bolt can be reliably prevented from loosening from the female screw. A high fastening force can be maintained semi-permanently.
(2) Since the outer peripheral portion of the bolt tip is provided with a sub-male screw portion formed so that the phase with respect to the main male screw portion is displaced by 12 to 100 °, preferably 24 to 90 °, and more preferably 24 to 72 °. By fastening the locking bolt to the female screw when fastening the member to be fastened, the secondary male screw part presses the female screw in the direction of the main male screw part, and the main male screw part becomes the secondary male screw. The reaction force that presses the female screw in the direction of the part, or the reaction force that the secondary male screw part presses the female screw in the direction opposite to the main male screw part, and the main male screw part that is opposite to the secondary male screw part A reaction force that presses the female screw in the direction is generated, whereby a large frictional force can be obtained between the main male screw part and the sub male screw part and the female screw, and the female screw is moved from the female screw to the main male screw part by vibration or the like. , Etc., and the screwing force can be reliably prevented from lowering. In addition, since the displacement amount is smaller than that in the related art, the screwing can be easily performed with a small resistance.
(3) When the tightening force is applied to the female screw by tightening the locking screw, the secondary male screw portion of the locking bolt is deformed by the tightening of the female screw to generate elastic deformation. Since the main male screw part and the sub male screw part can be more closely adhered and fastened, the screwing force between the locking bolt and the female screw can be further improved, and the locking bolt loosens from the female screw due to external force such as vibration. Can be more reliably prevented.
(4) Even if the part between the member to be fastened and the bearing surface is worn and loosened, the secondary male screw part presses the female screw in the direction of the main male screw part, or the secondary screw part. Can prevent the locking bolt from coming off from the female screw by the reaction force that presses the female screw in the direction opposite to the main male screw part, and can be used for bolts on vehicles and bridges with severe vibration such as automobiles and trains. And nuts can be prevented from falling.
(5) The main male screw part and the sub male screw part are firmly adhered to the female screw by the reaction force due to the elastic deformation generated by the secondary male screw part of the locking bolt screwed into the female screw being deformed by the female screw. As a result, it is possible to absorb rattling due to variations in the processing accuracy of the female screw and the male screw part of the locking bolt, and it is excellent in stability, and the phase displacement is small, so screws such as locking bolts and nuts at the time of fastening are used. Since it is difficult to damage the part and the reaction force can be stably obtained by elastic deformation, if the same female screw is used, remove the once screwed locking bolt and then screw it again and use it repeatedly. It can be used repeatedly.
(6) Since the main male screw portion has the annular groove formed to be the same as or deeper than the root of the main male screw portion, the main male screw portion can be smoothly screwed into the female screw when screwed, and the bolt tip portion Can be made thinner to facilitate compression deformation, and buckling of the main male screw portion and the like during compression deformation can be prevented.
(7) Since the elastic portion of the annular groove portion where the bolt tip is compressed and deformed has elasticity, in addition to the elastic deformation of the sub-male screw portion and the like caused by the screwed female screw, the elasticity caused by the screwed female screw By the elongation of the portion, while absorbing the backlash and the like due to variations in the processing accuracy of the female screw and the male screw portion of the locking bolt, the reaction force generated by the elastic force of the elastic portion can further increase the reaction force, The locking bolt can be more reliably prevented from loosening from the female screw.
(8) After forming the main male screw portion and the sub male screw portion with the same pitch and the same phase, the phase of the main male screw portion and the sub male screw portion can be easily shifted by compressively deforming the annular groove portion. Therefore, the production is easy and the productivity is excellent.
(9) Since the end recess is provided, the bolt end in which the annular groove is formed can be made thin, and the bolt end is easily compressed and deformed, and the productivity is excellent.
(10) By compressing the annular groove portion by the deformation amount α, the phase of the sub male screw portion with respect to the main male screw portion is reliably displaced to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °. The amount of deformation is appropriate, so the screw part is not scratched during fastening or seizure is less likely to occur during use, so it is excellent in repeated use, and even if the pitch or angle of the screw part varies, the flanks are pressed together during fastening. Is sufficiently obtained and the stability is excellent. In addition, the product yield is high and the productivity is excellent.
(11) By changing the value of n, the annular groove can be deformed to a predetermined amount. If the deformation of the annular groove is within the elastic limit, the elasticity of the elastic part can be changed. And the reaction force can be stably obtained, and the obtained reaction force has a small variation and is excellent in stability.
(12) Since the axial length L2 of the annular groove portion before the compression deformation is within a predetermined range of P ≦ L2 ≦ 5P + AB, the buckling load of the annular groove portion is adjusted to an appropriate amount, and the annular groove portion is compressed and deformed to form the secondary male screw portion. The phase can be easily displaced to a predetermined range, so that the productivity is excellent and the stability is excellent.
(13) Since the axial length L2 of the annular groove before compression deformation is within a predetermined range, the elastic portion can be accommodated in the annular groove when compressed and deformed. Excellent flexibility.
(14) By defining the cross-sectional area of the shaft portion of the annular groove portion, the reaction force exerted on the female screw by the sub-male screw portion can be set within a predetermined range, so that the locking is prevented without damaging the female screw or the male screw portion. It can be carried out.
(15) Since the thickness of the shaft portion of the annular groove portion is formed to a predetermined thickness and the mechanical strength can be set in a predetermined range, the phase of the secondary male screw portion can be easily set in a predetermined range when the bolt tip is compressed and deformed. Can be displaced. In addition, an appropriate amount of elongation is likely to occur in the shaft portion of the annular groove portion, and when the screw portion is screwed to the female screw, the shaft portion expands, so that the screw threads of the female screw and the sub-male screw portion are hardly crushed, and the mounting property is excellent.
(16) Since the deformation angle θ of the elastic part is formed within a predetermined range, the optimum elasticity of the elastic part can be obtained, and the relationship between the displacement of the elastic part and the reaction force can be stably obtained. Small variations in force and excellent stability.
(17) Since bolts standardized by JIS, ASME, DIN, etc. are processed, they are excellent in versatility.
[0035]
In the first embodiment, the case where the annular groove 6 is compressed and deformed by the deformation amount α (n is an integer of 0 or more) has been described. However, the tensile load is applied to the annular groove 6 and the deformation amount α (n Is 0) is −5 / 18 · P ≦ α ≦ −1 / 30 · P, preferably − ／ · P ≦ α ≦ −1 / 15 · P, more preferably −−１ · P ≦ α ≦ It is also possible to set the range of −1 / 15 · P. In this case, the same operation can be obtained.
[0036]
(Embodiment 2)
FIG. 6 is a cross-sectional view of a main part showing a state in which a member to be fastened is locked by a locking bolt according to the second embodiment. FIG. It is a diagram schematically showing the relationship between the stress and strain applied to the screw portion and the auxiliary male screw portion, the vertical axis indicates the stress applied to the main male screw portion and the auxiliary male screw portion, the horizontal axis is the main male screw portion and The amount of distortion of the secondary male screw part is shown. Note that the same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the drawing, reference numeral 30 denotes a locking bolt according to the second embodiment, and 31 denotes an axial direction of the bolt shaft portion 2 at a depth slightly larger than the root of the main male screw portion 5 on the outer periphery of the bolt tip portion 3 on the bolt shaft portion 2 side. An annular groove portion formed in an annular shape substantially orthogonal to the axis; 31a is a shaft portion of the annular groove portion 31; 32 is the same as the main male screw portion 5 on the outer periphery of the bolt tip portion 3 from the annular groove portion 31 toward the tip of the bolt tip portion 3; A secondary male screw formed by being pitched and phased with respect to the main male screw part 5 by 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °, and threaded or rolled with a lathe or the like. Department.
[0037]
The second embodiment differs from the first embodiment in that the locking bolt in the second embodiment does not compressively deform the annular groove to displace the phase of the sub-male screw portion, but instead performs threading or the like on a lathe or the like to form the main male screw portion. The point is that the phase of the sub male screw portion 32 with respect to 5 is displaced to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °.
[0038]
In the case where the member 21 is fastened by the locking bolt 30, the locking bolt 30 is inserted into the bolt hole 22 of the member 21 as shown in FIG. When the anti-loosening bolt 30 is screwed into the female screw 20, the main male screw part 5 and the sub male screw part 32 are larger than the elastic limit (point U in FIG. 7) and have the ultimate strength (point M in FIG. 7). A small stress (S point shown in FIG. 7) occurs. Thereby, the secondary male screw portion 32 is permanently set (0S shown in FIG. 7). ₁ ) Occurs, and the backlashes B and B ′ due to variations in the processing accuracy of the female screw 20, the main male screw part 5, and the sub male screw part 32 are oppositely reversed in the main male screw part 5 and the sub male screw part 32. Occurs. Further, elastic deformation (S shown in FIG. 7) ₁ S ₂ ), The auxiliary male screw portion 32 and the main male screw portion 5 are firmly fastened by pushing the female screw 20 in the forward and reverse directions of the flank.
The locking bolt 30 once screwed into the female screw 20 permanently sets the secondary male screw portion 32 according to the female screw 20 (0S shown in FIG. 7). ₁ ) Occurs and is deformed, and this deformation is maintained even after the female screw 20 is removed. Even when the anti-loosening bolt 30 is screwed into the female screw 20 again, the elastic deformation of the sub male screw part 32 (S shown in FIG. 7). ₁ S ₂ ) Acts on the female screw 20 and can be firmly fastened any number of times.
[0039]
As described above, since the locking bolt according to the second embodiment is configured, the following operation is obtained in addition to the operation described in the first embodiment.
(1) Since the phase of the sub male screw portion with respect to the main male screw portion (the phase with respect to the female screw to be screwed) is displaced by being screwed with a lathe or the like, no press equipment or the like for compressive deformation is required, and the equipment load is reduced. Can be reduced.
(2) Since the bolt tip can be made thinner by forming the annular groove and the tip recess, a reaction force corresponding to the screw can be obtained by optimizing mechanical strength such as elasticity and bending stress. In addition, it is possible to prevent the screw portion from being damaged and to prevent the screw portion from being loosened.
[0040]
It should be noted that the locking bolt in the first embodiment is the same as the elastic deformation (S in FIG. 7) described in the second embodiment. ₁ S ₂ ) And the reaction force (P) generated in the elastic portion 7 in the locking bolt in the first embodiment, the reaction force is larger than that in the second embodiment. A reaction force is obtained, and a large screwing force is obtained.
[0041]
【The invention's effect】
As described above, according to the locking bolt of the present invention, the following advantageous effects can be obtained.
According to the first aspect of the present invention,
(1) Since the phase of the sub male screw portion with respect to the main male screw portion is displaced by a predetermined amount, the flank of the main male screw portion of the press contact force generated by the tightening force of the locking screw tightened to the female screw portion is changed. The direction in which the flank of the female screw is pressed and the direction in which the flank of the sub male screw portion presses the flank of the female screw differ by 180 ° and are opposite to each other. For this reason, the direction of the torque generated by the pressing force and the lead angle of the screw is different between the main male screw part and the sub male screw part, and external force such as vibration is applied to the nut and the member to be fastened. When a force in the rotational direction is applied to the main male screw part to loosen, the torque generated in the flank of the sub male screw part acts in the tightening direction, so that the locking bolt can be reliably prevented from loosening from the female screw. A locking bolt capable of maintaining a high fastening force semipermanently can be provided.
(2) Since the outer peripheral portion of the bolt tip is provided with a sub-male screw portion formed so that the phase with respect to the main male screw portion is displaced by 12 to 100 °, preferably 24 to 90 °, and more preferably 24 to 72 °. By fastening the locking bolt to the female screw when fastening the member to be fastened, the secondary male screw part presses the female screw in the direction of the main male screw part, and the main male screw part becomes the secondary male screw. The reaction force that presses the female screw in the direction of the part, or the reaction force that the secondary male screw part presses the female screw in the direction opposite to the main male screw part, and the main male screw part that is opposite to the secondary male screw part A reaction force that presses the female screw in the direction is generated, whereby a large frictional force can be obtained between the main male screw part and the sub male screw part and the female screw, and the female screw is moved from the female screw to the main male screw part by vibration or the like. It is possible to provide a locking bolt which can surely prevent loosening of the screwing force.
(3) When a tightening force is applied to the female screw by tightening the locking screw, the secondary male screw portion of the locking bolt is deformed by the female screw to generate elastic deformation. Since the screw part and the auxiliary male screw part can be more firmly adhered and fastened, the screwing force between the locking bolt and the female screw can be further improved, and the locking bolt can be more loosened from the female screw due to external force such as vibration. It is possible to provide a locking bolt that can be reliably prevented.
(4) Even when looseness occurs due to wear between the member to be fastened and the seating surface, the secondary male screw part presses the female screw in the direction of the main male screw part, or the secondary male screw. The part prevents the locking bolt from coming off the female screw by the reaction force that presses the female screw in the direction opposite to the main male screw part, and even when applied to automobiles and bridges with severe vibration, It is possible to provide a locking bolt that can prevent a falling accident in which a nut comes off and falls.
(5) The main male screw part and the sub male screw part are firmly adhered to the female screw by the reaction force due to the elastic deformation generated by the secondary male screw part of the locking bolt screwed into the female screw being deformed by the female screw. Therefore, it is possible to absorb the rattling due to the variation in the processing accuracy of the female screw and the male screw part of the locking screw in the elastic deformation, and it is excellent in stability.Also, since the phase displacement amount is small, the locking screw Screws such as nuts are hardly damaged and the reaction force can be stably obtained by elastic deformation.If the same female screw is used, once the loosening bolts that have been screwed together are removed and screwed again. It is possible to provide a locking bolt excellent in repeated use.
(6) Since the main male screw portion has an annular groove formed to be the same as or deeper than the bottom of the main male screw portion, the main male screw portion can be smoothly screwed into the female screw while being compressed or pulled. Provided is a locking bolt which can be easily deformed, increases the degree of freedom in design, and can provide a locking bolt which can prevent the main male screw portion and the like from buckling during compression deformation. can do.
[0042]
According to the invention described in claim 2, in addition to the effect of claim 1,
(1) The shaft portion of the annular groove portion is made thinner by the concave portion at the tip, and the reaction force corresponding to the screw portion can be obtained by optimizing the mechanical strength such as elasticity and bending stress, thereby preventing the screw portion from being damaged and loosening. A locking bolt that can be made difficult can be provided.
[0043]
According to the invention described in claim 3, in addition to the effect of claim 2,
(1) Since the elastic portion of the annular groove portion where the bolt tip is compressed or tensilely deformed has elasticity, in addition to the elastic deformation of the sub-male screw portion and the like generated by the screwed female screw, the screwed female screw is used. Due to the elongation or contraction of the elastic part, the rattle and the like due to the variation in processing accuracy of the female screw and the male screw part of the locking bolt are absorbed, and the reaction force generated by the elasticity of the elastic part further increases. It is possible to provide a locking bolt that can more reliably prevent the locking bolt from loosening from the female screw.
(2) After the main male screw part and the sub male screw part are formed with the same pitch and the same phase, the phase of the main male screw part and the sub male screw part is easily shifted by compressing or stretching the annular groove part. Therefore, it is possible to provide a locking bolt which is easy to manufacture and excellent in productivity.
[0044]
According to the invention of claim 4, in addition to the effect of claim 3,
(1) By deforming the annular groove portion by the deformation amount α, the phase of the sub male screw portion with respect to the main male screw portion is reliably displaced to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °. Therefore, a locking bolt having a high product yield and excellent productivity can be provided.
(2) By changing the value of n, the annular groove can be deformed to a predetermined amount. If the deformation of the annular groove is within the elastic limit, the elasticity of the elastic part can be changed. And the reaction force can be stably obtained, and a variation in the obtained reaction force is small, and a locking bolt excellent in stability can be provided.
[0045]
According to the invention described in claim 5, in addition to the effect of any one of claims 1 to 4,
(1) By defining the cross-sectional area of the shaft portion of the annular groove portion, the reaction force Q applied to the female screw by the sub male screw portion can be set within a predetermined range, so that the idle torque Tq before fastening is approximately 1 to 50 N · m. Thus, a locking bolt excellent in fastening workability can be provided.
(2) Since the thickness of the shaft portion of the annular groove portion is formed to a predetermined thickness and the mechanical strength can be set in a predetermined range, the tip of the bolt is deformed to easily displace the phase of the secondary male screw portion to a predetermined range. Can be. In addition, an appropriate amount of elongation is likely to occur in the shaft portion of the annular groove portion, and when the screw portion is screwed to the female screw, the shaft portion expands, so that the screw thread of the female screw and the secondary male screw portion is hardly crushed, and a locking device excellent in mounting property is provided. Bolts can be provided.
[0046]
According to the invention described in claim 6,
(1) By compressing and deforming the bolt shaft portion in the annular groove portion having the leading end concave portion, the main male screw portion and the sub male screw portion that are out of phase can be easily formed, so that the manufacturing is easy and the production is easy. It is possible to provide a method of manufacturing a locking bolt excellent in property.
(2) Since the bolt shaft portion in the annular groove portion is deformed by the deformation amount α, the phase of the sub male screw portion with respect to the main male screw portion is set to 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °. Since it can be displaced reliably, it is possible to provide a method of manufacturing a locking bolt having excellent reliability and excellent workability.
[Brief description of the drawings]
FIG. 1A is an overall perspective view of a locking bolt according to Embodiment 1. FIG.
(B) Cross-sectional end view of a main part in the axial direction of FIG.
FIG. 2 (a) is a cross-sectional view of a main part showing a state before compressing and deforming an annular groove of a locking bolt according to the first embodiment;
(B) Sectional view of a bolt formed by processing a bolt to form a bolt tip and a tip recess
FIG. 3 is a cross-sectional end view of a main part showing a modification of the locking bolt according to the first embodiment.
FIG. 4 is an essential part cross-sectional view showing a state where the member to be fastened is fixed with the locking bolt according to the first embodiment;
FIG. 5 is a diagram schematically illustrating a relationship between a force and a displacement generated in an elastic portion when the member to be fastened is fastened with the locking bolt according to the first embodiment.
FIG. 6 is an essential part cross-sectional view showing a state where a member to be fastened is locked by a locking bolt according to the second embodiment;
FIG. 7 is a diagram schematically showing a relationship between stress and strain applied to a main male screw portion and a sub male screw portion when a member to be fastened is fastened with a locking bolt according to the second embodiment.
[Explanation of symbols]
1 Loosening bolt
2 Bolt shaft
3 Bolt tip
4 bolt head
5 Main male screw
5a male screw
6,6a annular groove
7 Elastic part
7a Shaft
8 Vice male screw part
8a male screw
9 Tip recess
10 Loosening bolt
11 annular groove
12 Tip recess
12a Large diameter recess
13 Elastic part
20 female screw
20a structure
21 Member to be fastened
22 bolt holes
30 Loosening bolt
31 annular groove
31a Shaft
32 Vice male screw part

Claims (6)

雌螺子に螺合して被締結部材を締結する緩み止めボルトであって、
ボルト軸部の先端部に前記ボルト軸部と同軸に形成されたボルト先端部と、前記ボルト軸部の外周に形成された主雄螺子部と、前記ボルト先端部の前記ボルト軸部側の外周に前記主雄螺子部の谷底と同一若しくは深い環状に形成された環状溝部と、前記主雄螺子部に対する位相が１２〜１００°好ましくは２４〜９０°より好ましくは２４〜７２°変位して前記ボルト先端部の外周に形成された副雄螺子部と、を備えていることを特徴とする緩み止めボルト。A locking bolt that is screwed into the female screw to fasten the member to be fastened,
A bolt tip formed coaxially with the bolt shaft at the tip of the bolt shaft, a main male screw formed at the outer periphery of the bolt shaft, and an outer periphery of the bolt tip at the bolt shaft side An annular groove formed in the same or deep annular shape as the bottom of the main male screw portion, and the phase with respect to the main male screw portion is displaced by 12 to 100 °, preferably 24 to 90 °, more preferably 24 to 72 °, And a sub male screw formed on the outer periphery of the bolt tip. 前記ボルト先端部が、前記ボルト先端部の軸中心に前記ボルト先端部の先端から少なくとも前記環状溝部まで形成された先端凹部を備えていることを特徴とする請求項１に記載の緩み止めボルト。2. The locking bolt according to claim 1, wherein the bolt tip includes a tip recess formed at an axial center of the bolt tip from the tip of the bolt tip to at least the annular groove. 3. 前記環状溝部における前記ボルト先端部が、軸方向に所定量だけ圧縮若しくは引張変形された弾性部を備えていることを特徴とする請求項２に記載の緩み止めボルト。The locking bolt according to claim 2, wherein the tip end of the bolt in the annular groove includes an elastic portion that has been compressed or tensile-deformed by a predetermined amount in an axial direction. 前記環状溝部の軸方向の変形量αが、前記主雄螺子部のピッチの大きさをＰとしたとき、（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ、好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐ、より好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）であることを特徴とする請求項３に記載の緩み止めボルト。The amount of deformation α in the axial direction of the annular groove portion is (n + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15), where P is the pitch size of the main male screw portion. ) P ≦ α ≦ (n + ／) P, more preferably (n + 1/15) P ≦ α ≦ (n + ／) P, or (n−5 / 18) P ≦ α ≦ (n−1 / 30) ) P preferably (n-−１) P ≦ α ≦ (n−1 / 15) P, more preferably (n − ／) P ≦ α ≦ (n−1 / 15) P (where n is The locking bolt according to claim 3, wherein α is an integer of 0 or more, and α is positive in the compression direction and negative in the tensile direction. 前記環状溝部の軸部の横断面積が、前記ボルト軸部の谷底における横断面積の５〜５０％であることを特徴とする請求項１乃至４の内いずれか１に記載の緩み止めボルト。The locking bolt according to any one of claims 1 to 4, wherein a cross-sectional area of the shaft portion of the annular groove portion is 5 to 50% of a cross-sectional area of the bolt shaft portion at a valley bottom. 雌螺子に螺合して被締結部材を締結する緩み止めボルトの製造方法であって、
ボルト軸部の軸中心に先端から穿設して先端凹部を形成する先端凹部形成工程と、
前記ボルト軸部の先端側の所定部の外周に雄螺子の谷底と同一若しくはそれより深い環状溝部を形成する環状溝部形成工程と、
前記ボルト軸部と略平行に所定荷重を所定時間印加して前記環状溝部形成工程で形成された前記環状溝部における前記ボルト軸部を、変形量αが前記雄螺子のピッチの大きさをＰとしたとき、（ｎ＋１／３０）Ｐ≦α≦（ｎ＋５／１８）Ｐ好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／４）Ｐより好ましくは（ｎ＋１／１５）Ｐ≦α≦（ｎ＋１／５）Ｐ、又は、（ｎ−５／１８）Ｐ≦α≦（ｎ−１／３０）Ｐ好ましくは（ｎ−１／４）Ｐ≦α≦（ｎ−１／１５）Ｐより好ましくは（ｎ−１／５）Ｐ≦α≦（ｎ−１／１５）Ｐ（但し、ｎは０以上の整数とする。αは圧縮方向を正、引張方向を負とする。）だけ変形させて弾性部を形成する弾性部形成工程と、
を備えていることを特徴とする緩み止めボルトの製造方法。A method for manufacturing a locking bolt for fastening a member to be fastened by being screwed into a female screw,
A tip recess forming step of forming a tip recess by drilling from the tip at the shaft center of the bolt shaft;
An annular groove forming step of forming an annular groove on the outer periphery of a predetermined portion on the distal end side of the bolt shaft portion that is the same as or deeper than the root of the male screw,
The bolt shaft in the annular groove formed in the annular groove forming step by applying a predetermined load for a predetermined time substantially in parallel with the bolt shaft, the deformation amount α is P, and the magnitude of the pitch of the male screw is P. Then, (n + 1/30) P ≦ α ≦ (n + 5/18) P, preferably (n + 1/15) P ≦ α ≦ (n + ／) P, more preferably (n + 1/15) P ≦ α ≦ (n + 1 / 5) P or (n−5 / 18) P ≦ α ≦ (n−1 / 30) P, preferably (n − ／) P ≦ α ≦ (n−1 / 15) P, more preferably ( n−1 / 5) P ≦ α ≦ (n−1 / 15) P (where n is an integer of 0 or more. α is positive in the compression direction and negative in the tensile direction) and elastically deformed. An elastic part forming step of forming a part,
A method for manufacturing a locking bolt, comprising:

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