JP4054573B2

JP4054573B2 - Synthetic resin rivet and its caulking method

Info

Publication number: JP4054573B2
Application number: JP2001385330A
Authority: JP
Inventors: 精武田
Original assignee: 武田精機株式会社
Priority date: 2001-10-30
Filing date: 2001-12-19
Publication date: 2008-02-27
Anticipated expiration: 2021-12-19
Also published as: JP2003202008A

Description

【０００１】
【発明の属する技術分野】
本発明は、合成樹脂リベットとそのかしめ方法に関する。
【０００２】
【従来の技術】
頭部と円筒状の脚部とからなる常温でかしめ付けができるようにした合成樹脂リベットは、特開平７−１９００２８号公報や特開２０００−１７９５１８号公報によって、既に知られている。
【０００３】
特開平７−１９００２８号公報の合成樹脂リベットは、図１２の（Ａ）に示すように、頭部ａの裏面に突設された脚部ｂが、先端側から所定の寸法の縦穴ｃを設けることによって、円筒状に形成され、縦穴ｃの底面ｄから頭部ａまでの部分が中実に形成されている。そして、図１２の（Ｂ）に示すように、複数の被締結部材ｅを重ね合わせて、それらに合成樹脂リベットを脚部ｂ先端側から押し込み、頭部ａの表面を支持した状態で、脚部ｂの先端を軸芯方向に押圧することにより、脚部ｂの先端を外方へ開拡しながらカールさせて、被締結部材ｅに当接した状態に塑性変形させ、加熱することなくかしめ付けができるように構成されている。
【０００４】
しかしながら、上記の合成樹脂リベットにおいては、かしめ付けを終了して押圧力を解除した際、脚部先端側のカール部分ｆが、その弾性力によってやや復元方向に戻るため、弾力性がない被締結部材ｅの場合には、カール部分ｆが被締結部材ｅから浮き上って、かしめが緩むというが問題点が指摘されている。
【０００５】
特開２０００−１７９５１８号公報の合成樹脂リベットは、この問題点を解決すべく提案されたもので、図１３の（Ａ）に示すように、脚部ｂに設ける縦穴ｃのうち、先端から中途部までの縦穴部分の内径を、中途部から底面までの縦穴部分の内径よりも大きくすることにより、頭部ａから中途部にかけて部分を厚肉の補強部ｇとして座屈しないようにする一方、中途部から先端にかけての部分を薄肉の非補強部ｈとして、脚部ｂ先端をカールさせ易くし、常温でかしめても、カール部分ｆに割れが発生しにくいようにしたものであり、非補強部ｈの長さＫ’をその外径Ｄ’と略等しくしてある。
【０００６】
そして、図１３の（Ｂ）に示すように、かしめ時において、非補強部ｈの内面が被締結部材ｅに当接するように、非補強部ｈのみをカールさせ、カール部分ｆが元の状態に復元する力が締め付け方向（図１３のＢに示す下向きの矢印方向）へと働き、時間の経過に伴ってかしめが緩むことがないようにしたものである。
【０００７】
また、非補強部ｈの長さＫ’が外径Ｄ’よりも小さ過ぎると、かしめ時にカールされる部分が短くなって、非補強部ｈの外面で被締結部材ｅを押えるようになり、非補強部ｈの長さＫ’が外径Ｄ’よりも大き過ぎると、座屈を起こし易くなると共に、かしめ後のカール部分ｆの山が高くなってしまうが、非補強部ｈの長さＫをその外径Ｄ’と略等しくしてあるので、このような不都合を回避できることになる。
【０００８】
尚、頭部ａの裏面は平坦であってもよいが、頭部裏面に環状凹部ｉを形成する場合は、かしめ時に頭部ａを扁平化するように弾性変形させ、頭部ａの復元力を締め付け方向（図１３のＢに示す上向きの矢印方向）に働かせて、カール部分ｆの復元力によって生じる押圧力と、頭部ａの復元力によって生じる押圧力とによって、被締結部材ｅを上下両面から挟み付けることにより、経時的なかしめの緩みをより確実に防止することができる。
【０００９】
【発明が解決しようとする課題】
しかしながら、図１３の合成樹脂リベットは、上述したとおり、非補強部ｈのカール部分ｆが元の状態に復元する力を利用して、かしめの緩み防止を行うものであるから、被締結部材ｅとして、カール部分ｆの復元力に対抗し得る硬さが要求されることになり、ボール紙やジーンズなどの布地のような柔らかな材質の被締結部材ｅでは、安定したかしめ付けが困難である。
【００１０】
しかも、図１３の（Ｂ）に示すように、剛性の小さい非補強部ｈのみをカールさせて、非補強部ｈの内面を被締結部材ｅに当接させるものであるから、補強部ｇの長さＨ’を、被締結部材ｅの厚みＴ’と略等しくすることが必要である。
【００１１】
従って、被締結部材ｅの厚みに応じて補強部ｇの長さＨ’を変更することが必要であり、厚さの異なる被締結部材ｅに対処するためには、脚部ｂの長さ（補強部ｇの長さＨ’＋非補強部ｈの長さＫ’）が異なる何種類もの合成樹脂リベットを用意しなければならないという問題点があった。
【００１２】
本発明は、これらの問題点を解決すべくなされたものであって、被締結部材がボール紙やジーンズなどの布地のような柔らかな材質であっても、安定したかしめ付けが可能であり、しかも、脚部の長さが一定した合成樹脂リベットを使用して、被締結部材の厚さが厚くても、薄くても、確実かつ良好なかしめ付けを行えるようにすることを目的としている。
【００１３】
【課題を解決するための手段】
上記の課題を解決するために、本発明が講じた技術的手段は、次のとおりである。即ち、本発明による合成樹脂リベットは、頭部と円筒状の脚部とからなる合成樹脂リベットであって、前記脚部の付け根部側に、縦穴の底面中央に開口した頭部に達する深さの小径縦穴が形成され、脚部の先端を外方へ彎曲させて折り返した状態において、脚部の縦穴開口端に半径方向内方への弾性復元力が作用するように構成し、折り返し筒部を外方へ開拡しながら押し潰して、二重構造のフランジ部を形成する状態に塑性変形させるように構成し、且つ、脚部の余分な合成樹脂部分は小径縦穴を埋めるように変形させるように構成してあることを特徴としている。
【００１４】
上記の合成樹脂リベットは、頭部の表面を支持した状態で、円筒状脚部の先端をかしめパンチで軸芯方向に押圧することにより、脚部の先端を外方へ彎曲させて折り返すことができる。この状態においては、脚部の先端側が、恰もゴムホースの開口端を半径方向外方へ折り返したように、折り返されており、脚部の縦穴開口端は、弾性復元力に抗して押し広げられているので、脚部の縦穴開口端には半径方向内方への弾性復元力が作用することになる。
【００１５】
従って、かしめパンチによる押圧の工程が進行することにより、脚部の折り返し部分は、脚部の外面に沿って頭部側へと押し動かされて行き、被締結部材と当接して、それ以上の移動が阻止された時点で、外方へ開拡しながら押し潰されて行き、二重構造のフランジ部を形成する状態に塑性変形して、常温でのかしめ付けが行われることになる。また、折り返し筒部を外方へ開拡しながら押し潰して、二重構造のフランジ部を形成する状態に塑性変形させることにより、折り返し筒部が扁平化されることになり、折り返し筒部を形成する脚部の長さが長くても、二重構造のフランジ部の山（被締結部材からの突出高さ）を低く抑えることができる。
【００１６】
本発明による合成樹脂リベットのかしめ方法は、頭部と円筒状の脚部とからなり、前記脚部の付け根部側に、縦穴の底面中央に開口した頭部に達する深さの小径縦穴が形成された合成樹脂リベットの前記脚部を被締結部材に形成された孔に挿通し、前記頭部の表面を支持した状態で、前記脚部の先端を軸芯方向に押圧することにより、先ず、脚部の先端を弾性復元力に抗して外方へ彎曲させて折り返して、環状中空部を有し且つ先端が前記脚部の外面に当接すると共に、半径方向内方への弾性復元力が作用する形状の折り返し筒部を形成し、この折り返し筒部を、当該折り返し筒部の先端が被締結部材と当接する位置まで脚部の外面に沿わせて頭部側へ押し動かした後、折り返し筒部を外方へ開拡しながら押し潰して塑性変形させ、脚部の余分な合成樹脂部分は小径縦穴を埋めるように変形させ、二重構造のフランジ部と頭部とで被締結部材を挟持するようにしたことを特徴としている。
【００１７】
上記の構成によれば、合成樹脂リベットの脚部を被締結部材に予め形成された孔に挿通し、頭部の表面を支持した状態で、脚部の先端をかしめパンチで軸芯方向に押圧することにより、恰もゴムホースの開口端を半径方向外方へ折り返したように、円筒状脚部の先端を外方へ彎曲させて折り返して、環状中空部を有し且つ先端を前記脚部の外面に当接させた形状の折り返し筒部が形成される。
【００１８】
そして、かしめパンチによる押圧の工程が進行することにより、上記の折り返し筒部が、脚部の外面に沿って頭部側へと押し動かされて行き、被締結部材と当接し、それ以上の移動が阻止された時点で、外方へ開拡しながら押し潰されて行き、二重構造のフランジ部を形成する状態に塑性変形するので、常温下において、ボール紙やジーンズなどの布地のような柔らかな材質の被締結部材に対しても安定したかしめ付けが可能である。また、折り返し筒部を外方へ開拡しながら押し潰して、二重構造のフランジ部を形成する状態に塑性変形させるので、折り返し筒部が扁平化されることになり、折り返し筒部を形成する脚部の長さが長くても、二重構造のフランジ部の山（被締結部材からの突出高さ）を低く抑えることができる。
【００１９】
殊に、上記の構成によれば、被締結部材の厚さが厚い場合には、折り返し筒部が、短い距離押し動かされて、被締結部材と当接し、それ以上の移動が阻止された時点で、かしめ付けが行われることになり、被締結部材の厚さが薄い場合には、折り返し筒部が、より長い距離押し動かされてから、被締結部材と当接し、それ以上の移動が阻止された時点で、かしめ付けが行われることになる。
【００２０】
被締結部材の厚さが薄い場合、折り返し筒部の移動距離が長く、かしめパンチの先端が縦穴の底面よりも低い位置まで進入することになるが、座屈防止を司る脚部の付け根部側には、縦穴の底面中央に開口した頭部に達する深さの小径縦穴が形成されているので、脚部の余分な合成樹脂部分は、かしめパンチの進入に伴い、小径縦穴を埋めるように変形させて、小径縦穴に逃がすことができ、被締結部材の厚さが薄いにもかかわらず、良好なかしめ状態が得られるのである。
【００２１】
従って、被締結部材の厚さが厚くても、薄くても、脚部の長さが同一の合成樹脂リベットを用いて、確実かつ良好なかしめ付けを行えるのであり、厚さの異なる被締結部材に対処するために、脚部の長さが異なる何種類もの合成樹脂リベットを用意しておく必要がなくなり、経済的である。
【００２２】
尚、円筒状の脚部のうち、脚部先端から縦穴の底面までの間に位置する薄肉部分の長さ（縦穴の深さ）が短すぎると、折り返し筒部を形成できず、長すぎる場合には、折り返し筒部を外方へ開拡しながら押し潰して塑性変形させた状態において、二重構造のフランジ部の直径が頭部に比して大きくなり過ぎるので、脚部先端から縦穴の底面までの間に位置する薄肉部分の長さ（縦穴の深さ）は、脚部の外径の略２倍であることが望ましい（請求項２）。
【００２３】
縦穴の底面中央に開口する小径縦穴の内径は、大き過ぎると、脚部の付け根部側による座屈防止の役目を果たすことができないので、かしめ時に力の集中する脚部の付け根部が座屈し易くなり、小さ過ぎると、被締結部材の厚さが薄い場合に生じる付け根部側の余分な合成樹脂部分を小径縦穴に逃がすことができないので、小径縦穴の内径は、縦穴の内径の１／２〜１／３であることが望ましい（請求項３）。
【００２４】
【発明の実施の形態】
図１は、本発明に係る合成樹脂リベットＡの一例を示す。図２〜図５は、前記合成樹脂リベットＡを厚さＴの厚い被締結部材Ｂにかしめ付けるかしめ方法を示し、図６〜図１１は、前記合成樹脂リベットＡを厚さＴの薄い被締結部材Ｂにかしめ付けるかしめ方法を示す。
【００２５】
前記合成樹脂リベットＡは、例えばポリアセタール、ポリエステル等の合成樹脂材料の射出成形法により製造されたもので、頭部１とその裏面に突設された円筒状の脚部２とからなる。頭部１の表面は、球面状とされているが、平面状のものや他の形状でもよく、特に限定されない。また、頭部１の裏面には、脚部２の周囲に環状凹部３が形成されているが、平坦であってもよく、リブや小突起を設けてもよく、特に限定されない。４は、脚部２の先端側から付け根部側の所定位置まで設けられた円形の縦穴である。
【００２６】
前記脚部２の付け根部側には、縦穴４の底面５中央に開口した少なくとも頭部１に達する深さの円形の小径縦穴６が形成されている。従って、射出成形後の温度低下による樹脂のヒケにより、頭部１の表面中央に凹部が発生することを防止できる。円筒状の脚部２のうち、脚部２先端から縦穴４の底面５までの間に位置する薄肉部分の長さ（縦穴４の深さ）Ｋは、脚部２の外径Ｄの略２倍に設定されている。そして、後述するとおり、脚部２の先端を外方へ彎曲させて折り返した状態において、脚部２の縦穴４開口端に半径方向内方への弾性復元力が作用するように構成してある。
【００２７】
尚、縦穴４、小径縦穴６の内面には射出成形用金型の抜き勾配が付けられている。Ｈは、縦穴４の底面５から頭部１の外周部１ａまでの長さである。図示の例では、前記小径縦穴６を、縦穴４の底面５から頭部１の外周部１ａまでの長さＨよりも若干深くし、環状凹部３と略合致する深さとしてあるが、頭部１の外周部１ａまでの長さＨと同じ深さでもよく、頭部１の厚みが大きい場合には、環状凹部３よりも深く設定してもよい。Ｌ₁は縦穴４の内径、Ｌ₂は小径縦穴６の内径である。小径縦穴６の内径Ｌ₂は、縦穴の内径Ｌ₁の１／２〜１／３に設定されている。例えば、縦穴４の内径Ｌ₁が２．５ｍｍである場合、小径縦穴６の内径Ｌ₂は１ｍｍ程度に設定される。
【００２８】
次に、上述した合成樹脂リベットＡを、常温下で、厚さＴの厚い被締結部材Ｂにかしめ付ける場合と、厚さＴの薄い被締結部材Ｂにかしめ付ける場合とを、図面に基づいて説明する。
【００２９】
図２に示すように、合成樹脂リベットＡの脚部２を被締結部材Ｂに予め形成された孔に挿通し、頭部１を受け台Ｃ₁で支持した状態で、前記脚部２の先端を、受け台Ｃ₁に対して相対的に昇降するかしめパンチＣ₂で、軸芯方向に押圧することにより、前記脚部２の先端部を外側に押し潰して、常温下で、かしめ付けを行うにあたり、図３、図４に示すように、受け台Ｃ₁に対するかしめパンチＣ₂の接近移動（図示の例では下降）に伴い、先ず、脚部２の先端を、その弾性復元力に抗して外方へ彎曲させて折り返し、折り返し端に環状中空部７を有し且つ先端が前記脚部２の外面に当接した形状の折り返し筒部２ａを形成する。折り返し筒部２ａは、図４に示すように、恰もゴムホースの開口端を半径方向外方へ折り返したような状態にあり、縦穴４開口端（折り返し筒部２ａの先端）には、図３に矢印で示すように、半径方向内方への弾性復元力が作用している。
【００３０】
そして、かしめパンチＣ₂による押圧の工程が進行することにより、折り返し筒部２ａを、当該折り返し筒部２ａの先端が被締結部材Ｂと当接する位置まで脚部２の外面に沿わせて押し動かす。
【００３１】
この状態から、かしめパンチＣ₂が更に受け台Ｃ₁に接近移動して、かしめパンチＣ₂による押圧の工程が進行すると、折り返し筒部２ａのそれ以上の移動が被締結部材Ｂにより阻止されるので、図５に示すように、かしめパンチＣ₂が折り返し筒部２ａを外方へ開拡しながら押し潰して塑性変形させることになり、高さの低い二重構造のフランジ部２ｂと頭部１とで被締結部材Ｂを挟持し、かしめ付けが完了することになる。
【００３２】
脚部２の付け根部側は、縦穴４と小径縦穴６の直径差により肉厚となっているので、座屈防止の役目を果たすことができ、かしめ時に力の集中する脚部２の付け根部近辺での座屈が防止されることになる。
【００３３】
被締結部材Ｂの厚さＴが厚い場合には、折り返し筒部２ａが短い距離下降するだけで、折り返し筒部２ａの先端が被締結部材Ｂと当接し、それ以上の移動を阻止された時点で、かしめ付けが行われるが、図６に示すように、被締結部材Ｂの厚さＴが薄い場合には、図７〜図１１に示すように、折り返し筒部２ａがより長い距離下降してから、折り返し筒部２ａの先端が被締結部材Ｂと当接して、それ以上の移動を阻止された時点で、かしめ付けが行われることになる。
【００３４】
即ち、図６に示すように、合成樹脂リベットＡの脚部２を被締結部材Ｂに予め形成された孔に挿通し、頭部１を受け台Ｃ₁で支持した状態で、前記脚部２の先端を、受け台Ｃ₁に対して相対的に昇降するかしめパンチＣ₂で、軸芯方向に押圧することにより、前記脚部２の先端部を外側に押し潰して、常温下で、かしめ付けを行うにあたり、図７、図８に示すように、受け台Ｃ₁に対するかしめパンチＣ₂の接近移動（図示の例では下降）に伴い、先ず、脚部２の先端を、その弾性復元力に抗して外方へ彎曲させて折り返し、折り返し端に環状中空部７を有し且つ先端が前記脚部２の外面に当接した形状の折り返し筒部２ａを形成する。この折り返し筒部２ａは、図７、図８に示すように、恰もゴムホースの開口端を半径方向外方へ折り返したような状態にあり、縦穴４開口端（折り返し筒部２ａの先端）には、図７に矢印で示すように、半径方向内方への弾性復元力が作用している。
【００３５】
そして、かしめパンチＣ₂による押圧の工程が進行することにより、図９、図１０に示すように、折り返し筒部２ａを、当該折り返し筒部２ａの先端が被締結部材Ｂと当接する位置まで脚部２の外面に沿わせて押し動かす。この状態においては、縦穴４開口端（折り返し筒部２ａの先端）には、図９に矢印で示すように、半径方向内方への弾性復元力が作用している。
【００３６】
この状態から、かしめパンチＣ₂が更に受け台Ｃ₁に接近移動して、かしめパンチＣ₂による押圧の工程が進行すると、折り返し筒部２ａのそれ以上の移動が被締結部材Ｂにより阻止されるので、図１１に示すように、かしめパンチＣ₂が折り返し筒部２ａを外方へ開拡しながら押し潰して塑性変形させることになり、折り返し筒部２ａが扁平化されて、高さの低い二重構造のフランジ部２ｂが形成され、この二重構造のフランジ部２ｂと頭部１とで被締結部材Ｂを挟持し、かしめ付けが完了することになる。
【００３７】
以上のとおり、かしめパンチＣ₂による押圧の工程が進行することにより、折り返し筒部２ａが、脚部２の外面に沿って頭部１側へと押し動かされて行き、被締結部材Ｂと当接し、それ以上の移動が阻止された時点で、外方へ開拡しながら押し潰されて行き、二重構造のフランジ部２ｂを形成する状態に塑性変形するので、ボール紙やジーンズなどの布地のような柔らかな材質の被締結部材Ｂに対しても安定したかしめ付けが可能である。また、折り返し筒部２ａを外方へ開拡しながら押し潰して、二重構造のフランジ部２ｂを形成する状態に塑性変形させるので、折り返し筒部２ａが扁平化されることになり、折り返し筒部２ａを形成する脚部２の薄肉部分の長さ（縦穴４の深さ）Ｋが長くても、二重構造のフランジ部２ｂの山（被締結部材Ｂからの突出高さ）を低く抑えることができる。
【００３８】
被締結部材Ｂの厚さが薄い場合、折り返し筒部２ａの移動距離が長く、かしめパンチＣ₂の先端が縦穴４の底面５よりも低い位置まで進入することになるが、座屈防止を司る脚部２の付け根部側には、縦穴４の底面５中央に開口した頭部１に達する深さの小径縦穴６が形成されているので、脚部２の余分な合成樹脂部分は、かしめパンチＣ₂の進入に伴い、図１１に示すように、小径縦穴６を埋めるように変形させて、小径縦穴６に逃がすことができ、被締結部材Ｂの厚さが薄いにもかかわらず、良好なかしめ状態が得られるのである。
【００３９】
従って、被締結部材Ｂの厚さが厚くても、薄くても、同一寸法の合成樹脂リベットＡを用いて、確実かつ良好なかしめ付けを行えるのであり、厚さの異なる被締結部材Ｂに対処するために、脚部２の長さが異なる何種類もの合成樹脂リベットを用意しておく必要がなくなり、経済的である。
【００４０】
尚、円筒状の脚部２のうち、脚部先端から縦穴４の底面５までの間に位置する薄肉部分の長さ（縦穴４の深さ）Ｋを、脚部２の外径Ｄの略２倍に設定したのは、次の理由による。即ち、薄肉部分の長さ（縦穴４の深さ）Ｋが短すぎると、折り返し筒部２ａを形成できず、長すぎる場合には、折り返し筒部２ａを外方へ開拡しながら押し潰して塑性変形させた状態において、二重構造のフランジ部２ｂの直径が頭部１に比して大きくなり過ぎるからである。
【００４１】
また、小径縦穴６の内径Ｌ₂を、縦穴４の内径Ｌ₁の１／２〜１／３に設定したのは、次の理由による。即ち、縦穴４の底面５中央に開口する小径縦穴６の内径Ｌ₂は、大き過ぎると、脚部２の付け根部側による座屈防止の役目を果たすことができず、かしめ時に力の集中する脚部２の付け根部が座屈し易くなり、小さ過ぎると、被締結部材Ｂの厚さが薄い場合に生じる付け根部側の余分な合成樹脂部分を小径縦穴６に逃がすことができないからである。
【００４２】
上述した実施の形態において、受け台Ｃ₁に対して相対的に昇降するかしめパンチＣ₂とは、受け台Ｃが固定で、かしめパンチＣ₂のみが昇降動作する場合と、これとは逆に、かしめパンチＣ₂が固定で、受け台Ｃ₁のみが昇降動作する場合と、受け台Ｃ₁およびかしめパンチＣ₂の双方が昇降動作（互いに遠近移動）する場合とを包含する意味である。また、図示の例では、合成樹脂リベットＡの頭部１が下に来るように、受け台Ｃ₁の上方にかしめパンチＣ₂を配置し、脚部２の先端を上方から押圧しているが、これらの上下関係を逆にして、かしめ付けを行うことも可能である。
【００４３】
【発明の効果】
本発明は、上述した構成よりなるから、被締結部材がボール紙やジーンズなどの布地のような柔らかな材質であっても、安定したかしめ付けが可能であり、しかも、脚部の長さが一定した合成樹脂リベットを使用して、被締結部材の厚さが厚くても、薄くても、確実かつ良好なかしめ付けを行え、厚さの異なる被締結部材に対処するために、脚部の長さが異なる何種類もの合成樹脂リベットを用意しておく必要がなくなるので、経済的である等の効果がある。
【図面の簡単な説明】
【図１】本発明に係る合成樹脂リベットの縦断側面図である。
【図２】図１の合成樹脂リベットを厚い被締結部材にかしめ付ける方法を説明するための縦断側面図である。
【図３】かしめ途中の状態における縦断側面図である。
【図４】図３の状態における合成樹脂リベットの側面図である。
【図５】かしめ付けが完了した状態における縦断側面図である。
【図６】図１の合成樹脂リベットを薄い被締結部材にかしめ付ける方法を説明するための縦断側面図である。
【図７】かしめ途中の状態における縦断側面図である。
【図８】図７の状態における合成樹脂リベットの側面図である。
【図９】かしめ途中の状態における縦断側面図である。
【図１０】図９の状態における合成樹脂リベットの側面図である。
【図１１】かしめ付けが完了した状態における縦断側面図である。
【図１２】従来例を説明する縦断面図である。
【図１３】従来例を説明する縦断面図である。
【符号の説明】
Ａ…合成樹脂リベット、Ｂ…被締結部材、１…頭部、２…脚部、２ａ…折り返し筒部、２ｂ…二重構造のフランジ部、４…縦穴、５…底面、６…小径縦穴。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic resin rivet and a caulking method thereof.
[0002]
[Prior art]
Synthetic resin rivets comprising a head and a cylindrical leg and capable of being caulked at room temperature are already known from Japanese Patent Application Laid-Open Nos. 7-190028 and 2000-179518.
[0003]
In the synthetic resin rivet disclosed in Japanese Patent Laid-Open No. 7-190028, as shown in FIG. 12A, a leg portion b protruding from the back surface of the head a is provided with a vertical hole c having a predetermined dimension from the tip side. Thereby, it is formed in a cylindrical shape, and the part from the bottom surface d of the vertical hole c to the head a is formed solid. Then, as shown in FIG. 12B, the plurality of fastened members e are overlapped, and a synthetic resin rivet is pushed into them from the tip end side of the leg portion b, and the leg is supported in a state where the surface of the head a is supported. By pressing the tip of the portion b in the axial direction, the tip of the leg b is curled while expanding outwardly, plastically deformed to abut against the fastened member e, and caulked without heating. It is configured so that it can be attached.
[0004]
However, in the above synthetic resin rivet, when the caulking is finished and the pressing force is released, the curled portion f on the distal end side of the leg portion returns to the restoring direction due to its elastic force, so that it is not elastic. In the case of the member e, a problem has been pointed out that the curled portion f rises from the fastened member e and the caulking is loosened.
[0005]
The synthetic resin rivet disclosed in Japanese Patent Laid-Open No. 2000-179518 has been proposed to solve this problem. As shown in FIG. 13A, the synthetic resin rivet is halfway from the tip of the vertical hole c provided in the leg b. While making the inner diameter of the vertical hole part to the part larger than the inner diameter of the vertical hole part from the midway part to the bottom surface, while preventing the part from buckling as a thick reinforcing part g from the head a to the midway part, The part from the middle part to the tip is a thin non-reinforcing part h so that the tip of the leg part b can be easily curled so that the curled part f does not easily crack even when caulked at room temperature. The length K ′ of the portion h is substantially equal to the outer diameter D ′.
[0006]
Then, as shown in FIG. 13B, only the non-reinforcing part h is curled so that the inner surface of the non-reinforcing part h comes into contact with the fastened member e at the time of caulking, and the curled part f is in the original state. Thus, the force to restore the squeezing acts in the tightening direction (downward arrow direction shown in FIG. 13B) so that the caulking does not loosen over time.
[0007]
If the length K ′ of the non-reinforcing part h is too smaller than the outer diameter D ′, the part that is curled during caulking is shortened, and the member e to be fastened can be pressed on the outer surface of the non-reinforcing part h. If the length K ′ of the non-reinforcing portion h is too larger than the outer diameter D ′, buckling is likely to occur, and the peak of the curled portion f after caulking becomes high. Since K is substantially equal to the outer diameter D ′, such inconvenience can be avoided.
[0008]
The back surface of the head a may be flat, but when the annular recess i is formed on the back surface of the head, the head a is elastically deformed so as to be flattened during caulking, and the restoring force of the head a is restored. Is moved in the tightening direction (the upward arrow direction shown in FIG. 13B), and the fastened member e is moved up and down by the pressing force generated by the restoring force of the curled portion f and the pressing force generated by the restoring force of the head a. By sandwiching from both sides, loosening of the caulking with time can be more reliably prevented.
[0009]
[Problems to be solved by the invention]
However, as described above, the synthetic resin rivet shown in FIG. 13 prevents the caulking from being loosened by using the force that restores the curled portion f of the non-reinforcing portion h to the original state. Therefore, hardness that can resist the restoring force of the curled portion f is required, and it is difficult to perform stable caulking with a fastened member e made of a soft material such as a cloth such as cardboard or jeans. .
[0010]
Moreover, as shown in FIG. 13B, only the non-reinforcing part h having a small rigidity is curled and the inner surface of the non-reinforcing part h is brought into contact with the fastened member e. It is necessary to make the length H ′ substantially equal to the thickness T ′ of the fastened member e.
[0011]
Therefore, it is necessary to change the length H ′ of the reinforcing portion g according to the thickness of the fastened member e. In order to cope with the fastened members e having different thicknesses, the length of the leg portion b ( There was a problem that various types of synthetic resin rivets having different lengths H ′ of the reinforcing portions g + K lengths of the non-reinforcing portions h) had to be prepared.
[0012]
The present invention has been made to solve these problems, and even if the member to be fastened is a soft material such as a cloth such as cardboard or jeans, stable caulking is possible. In addition, it is an object to use a synthetic resin rivet having a constant leg length so that reliable and good caulking can be performed regardless of whether the member to be fastened is thick or thin.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the technical means taken by the present invention are as follows. That is, the synthetic resin rivet according to the present invention is a synthetic resin rivet composed of a head and a cylindrical leg, and has a depth reaching the head opening at the base of the vertical hole at the base of the leg. In the state where the small-diameter vertical hole is formed and the front end of the leg is bent outward and folded, the elastic restoring force radially inward acts on the opening end of the vertical hole in the leg , and the folded tube portion It is configured to be plastically deformed in a state of forming a double-structure flange portion while being expanded outwardly, and the excess synthetic resin portion of the leg portion is deformed to fill a small-diameter vertical hole. It is characterized by being configured as follows.
[0014]
The above synthetic resin rivet can be folded back by bending the tip end of the leg portion outward by crimping the tip end of the cylindrical leg portion in the axial direction with a punch while supporting the surface of the head. it can. In this state, the front end side of the leg portion is folded back so that the opening end of the rubber hose is folded back radially outward, and the vertical hole opening end of the leg portion is expanded against the elastic restoring force. Therefore, the elastic restoring force inward in the radial direction acts on the opening end of the vertical hole of the leg portion.
[0015]
Accordingly, as the pressing process by the caulking punch proceeds, the folded portion of the leg portion is pushed and moved toward the head side along the outer surface of the leg portion, and comes into contact with the member to be fastened. When the movement is blocked, it is crushed while spreading outward, and is plastically deformed to form a double-structured flange, and caulking is performed at room temperature. In addition, the folded tube portion is flattened while being expanded outwardly and plastically deformed to form a double-structured flange portion, whereby the folded tube portion is flattened. Even if the length of the leg part to be formed is long, the peak of the double-structured flange part (projection height from the fastened member) can be kept low.
[0016]
The method of caulking a synthetic resin rivet according to the present invention comprises a head and a cylindrical leg, and a small-diameter vertical hole having a depth reaching the head opened at the bottom center of the vertical hole is formed on the base of the leg. By inserting the leg portion of the synthetic resin rivet through a hole formed in the fastened member and supporting the surface of the head, pressing the tip of the leg portion in the axial direction first, folded by curved outwardly against the front end of the leg elastic restoring force, with and tip has an annular hollow portion abuts against the outer surface of the leg, the elastic restoring force in the radially inward After forming the folded cylinder part of the shape that acts, and pushing the folded cylinder part to the head side along the outer surface of the leg part to the position where the tip of the folded cylinder part contacts the fastened member, crushed while diverging the folded cylindrical portion outwardly plastically deformed surplus leg Do synthetic resin portion is characterized in that so as to deform to fill the small diameter vertical hole, sandwiching the workpieces between the flange portion and the head portion of the double structure.
[0017]
According to the above configuration, the leg portion of the synthetic resin rivet is inserted into the hole formed in the fastening member in advance, and the tip of the leg portion is caulked and pressed in the axial direction with the punch while supporting the head surface. By doing so, the end of the cylindrical leg is bent outward and folded so that the opening end of the rubber hose is folded back radially outward, and has an annular hollow portion, and the tip is formed on the outer surface of the leg. A folded tube portion having a shape brought into contact with is formed.
[0018]
Then, as the pressing process by the caulking punch proceeds, the folded tube portion is pushed toward the head side along the outer surface of the leg portion, abuts on the fastened member, and moves further When it is blocked, it is crushed while spreading outward, and plastically deforms to form a double-structured flange, so at room temperature, such as a cloth such as cardboard or jeans Stable caulking is possible even for a fastened member made of a soft material. In addition, the folded tube portion is crushed while expanding outward, and is plastically deformed to form a double-structured flange portion, so that the folded tube portion is flattened, forming the folded tube portion Even if the length of the leg portion to be made is long, the peak of the double-structured flange portion (projection height from the fastened member) can be kept low.
[0019]
In particular, according to the above configuration, when the thickness of the member to be fastened is thick, the folded tube portion is pushed and moved a short distance to contact the member to be fastened and further movement is prevented. In this case, when the thickness of the fastened member is thin, the folded tube portion is pushed and moved for a longer distance and then comes into contact with the fastened member to prevent further movement. At that time, caulking will be performed.
[0020]
When the thickness of the fastened member is thin, the moving distance of the folded tube part is long, and the tip of the caulking punch enters to a position lower than the bottom surface of the vertical hole. Has a small-diameter vertical hole with a depth reaching the head opening at the center of the bottom of the vertical hole, so that the excess synthetic resin part of the leg is deformed to fill the small-diameter vertical hole as the caulking punch enters Thus, it is possible to escape to the small-diameter vertical hole, and a good caulking state can be obtained even though the member to be fastened is thin.
[0021]
Therefore, it is possible to perform secure and good caulking using synthetic resin rivets having the same leg length regardless of whether the thickness of the fastened member is thick or thin. Therefore, it is not necessary to prepare various kinds of synthetic resin rivets having different leg lengths, which is economical.
[0022]
If the length of the thin portion (depth of the vertical hole) located between the tip of the leg portion and the bottom surface of the vertical hole is too short among the cylindrical leg portions, the folded tube portion cannot be formed and is too long. In the state where the folded tube portion is crushed while being expanded outward and is plastically deformed, the diameter of the double-structure flange portion is too large compared to the head portion, It is desirable that the length (depth of the vertical hole) of the thin portion located between the bottom surface is approximately twice the outer diameter of the leg portion (Claim 2).
[0023]
If the inside diameter of the small-diameter vertical hole opening in the center of the bottom of the vertical hole is too large, it cannot serve to prevent buckling by the base of the leg, so the base of the leg where the force concentrates during buckling will buckle. If it is too small, excess synthetic resin part on the base side that occurs when the thickness of the fastened member is thin cannot be released to the small diameter vertical hole, so the inner diameter of the small diameter vertical hole is 1/2 of the inner diameter of the vertical hole It is desirable that it is ˜1 / 3 (Claim 3).
[0024]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of a synthetic resin rivet A according to the present invention. 2 to 5 show a caulking method for caulking the synthetic resin rivet A to a fastened member B having a thickness T, and FIGS. 6 to 11 show fastening the synthetic resin rivet A having a thin thickness T. A caulking method for caulking the member B will be described.
[0025]
The synthetic resin rivet A is manufactured by, for example, an injection molding method of a synthetic resin material such as polyacetal and polyester, and includes a head 1 and a cylindrical leg 2 projecting from the back surface thereof. The surface of the head 1 is spherical, but it may be planar or other shapes, and is not particularly limited. Moreover, although the annular recessed part 3 is formed in the circumference | surroundings of the leg part 2 at the back surface of the head 1, it may be flat and may provide a rib and a small protrusion, and is not specifically limited. 4 is a circular vertical hole provided from the front end side of the leg part 2 to a predetermined position on the base part side.
[0026]
A circular small-diameter vertical hole 6 having a depth reaching at least the head 1 that is open at the center of the bottom surface 5 of the vertical hole 4 is formed on the base side of the leg 2. Therefore, it is possible to prevent a concave portion from being generated at the center of the surface of the head 1 due to resin sink due to a temperature drop after injection molding. Of the cylindrical leg 2, the length K (depth of the vertical hole 4) K between the tip of the leg 2 and the bottom surface 5 of the vertical hole 4 is approximately 2 of the outer diameter D of the leg 2. It is set to double. And, as will be described later, in the state where the tip of the leg 2 is bent outward and folded, the elastic restoring force radially inward acts on the opening end of the vertical hole 4 of the leg 2. .
[0027]
The inner surface of the vertical hole 4 and the small diameter vertical hole 6 is provided with a draft of an injection mold. H is the length from the bottom surface 5 of the vertical hole 4 to the outer peripheral portion 1 a of the head 1. In the illustrated example, the small-diameter vertical hole 6 is made slightly deeper than the length H from the bottom surface 5 of the vertical hole 4 to the outer peripheral portion 1a of the head 1, and has a depth substantially matching the annular recess 3. 1 may be the same depth as the length H to the outer peripheral portion 1a, and may be set deeper than the annular recess 3 when the thickness of the head 1 is large. L ₁ is the inner diameter of the vertical hole 4, and L ₂ is the inner diameter of the small-diameter vertical hole 6. The inner diameter L ₂ of the small diameter longitudinal hole 6 is set to 1 / 2-1 / 3 of the longitudinal hole of the inner diameter L _1. For example, when the inner diameter L _{1 of the} vertical hole 4 is 2.5 mm, the inner diameter L ₂ of the small diameter vertical hole 6 is set to about 1 mm.
[0028]
Next, a case where the above-described synthetic resin rivet A is caulked to a fastened member B having a large thickness T and a case where it is caulked to a fastened member B having a thin thickness T based on the drawings. explain.
[0029]
As shown in FIG. 2, the leg 2 of the synthetic resin rivet A is inserted into a hole formed in the fastened member B in advance, and the head 1 is supported by the cradle C ₁ with the tip of the leg 2 Is pressed in the axial direction with a caulking punch C ₂ that moves up and down relatively with respect to the cradle C ₁ , thereby crushing the tip of the leg 2 outward and caulking at room temperature. 3 and 4, when the caulking punch C ₂ moves closer to the cradle C ₁ (lowering in the illustrated example), the tip of the leg 2 is first resisted against its elastic restoring force. Then, the folded tube portion 2a having a shape in which the annular hollow portion 7 is provided at the folded end and the tip is in contact with the outer surface of the leg portion 2 is formed. As shown in FIG. 4, the folded tube portion 2a is in a state where the opening end of the rubber hose is folded radially outward, and the opening end of the vertical hole 4 (the tip of the folded tube portion 2a) is shown in FIG. As indicated by the arrow, an elastic restoring force inward in the radial direction is acting.
[0030]
Then, as the pressing step by the caulking punch C ₂ proceeds, the folded tube portion 2a is pushed along the outer surface of the leg portion 2 to a position where the tip of the folded tube portion 2a contacts the fastened member B. .
[0031]
From this state, when the caulking punch C ₂ further moves closer to the cradle C ₁ and the pressing process by the caulking punch C ₂ proceeds, further movement of the folded tube portion 2a is prevented by the fastened member B. Therefore, as shown in FIG. 5, the caulking punch C ₂ is crushed and plastically deformed while expanding the folded tube portion 2a outward, and the low-height dual-structure flange portion 2b and head The clamped member B is clamped by 1 and the caulking is completed.
[0032]
The base of the leg 2 is thick due to the difference in diameter between the vertical hole 4 and the small-diameter vertical hole 6, so that it can play a role in preventing buckling and the base of the leg 2 where the force concentrates during caulking. Buckling in the vicinity will be prevented.
[0033]
When the thickness T of the fastened member B is thick, when the folded tube portion 2a is lowered by a short distance, the tip of the folded tube portion 2a comes into contact with the fastened member B and further movement is prevented. However, as shown in FIG. 6, when the thickness T of the fastened member B is thin, as shown in FIGS. 7 to 11, the folded tube portion 2a is lowered for a longer distance. Then, when the tip of the folded tube portion 2a comes into contact with the fastened member B and further movement is prevented, the caulking is performed.
[0034]
That is, as shown in FIG. 6, the leg 2 is inserted in a state in which the leg 2 of the synthetic resin rivet A is inserted through a hole formed in the fastening member B in advance and supported by the cradle C _1. The tip of the leg 2 is pressed in the axial direction by a caulking punch C ₂ that moves up and down relative to the cradle C ₁ , thereby crushing the tip of the leg 2 outward and caulking at room temperature. 7 and 8, as shown in FIGS. 7 and 8, as the caulking punch C ₂ approaches (lowers in the illustrated example) with respect to the cradle C ₁ , first, the tip of the leg 2 is moved to its elastic restoring force. The bent tube portion 2a is formed to be bent outward and bent to have an annular hollow portion 7 at the turned-up end and whose tip is in contact with the outer surface of the leg portion 2. As shown in FIGS. 7 and 8, the folded tube portion 2a is in a state where the open end of the rubber hose is folded outward in the radial direction, and at the open end of the vertical hole 4 (the tip of the folded tube portion 2a). As shown by the arrows in FIG. 7, an elastic restoring force inward in the radial direction is acting.
[0035]
Then, as the pressing process by the caulking punch C ₂ proceeds, the folded tube portion 2a is moved to the position where the tip of the folded tube portion 2a contacts the fastened member B as shown in FIGS. Push along the outer surface of part 2. In this state, an elastic restoring force radially inward acts on the opening end of the vertical hole 4 (the tip of the folded tube portion 2a), as indicated by an arrow in FIG.
[0036]
From this state, when the caulking punch C ₂ further moves closer to the cradle C ₁ and the pressing process by the caulking punch C ₂ proceeds, further movement of the folded tube portion 2a is prevented by the fastened member B. Therefore, as shown in FIG. 11, the caulking punch C ₂ is crushed and plastically deformed while expanding the folded tube portion 2a outward, and the folded tube portion 2a is flattened and has a low height. The double-structured flange portion 2b is formed, and the fastened member B is sandwiched between the double-structured flange portion 2b and the head portion 1 to complete the caulking.
[0037]
As described above, as the pressing process by the caulking punch C ₂ proceeds, the folded tube portion 2a is pushed toward the head 1 side along the outer surface of the leg portion 2, and is brought into contact with the fastened member B. When contact is made and further movement is prevented, it is crushed while expanding outward and plastically deformed to form a double-structured flange 2b. Stable caulking is possible even for the fastened member B made of such a soft material. Further, the folded tube portion 2a is crushed while being expanded outwardly and is plastically deformed to form a double-structured flange portion 2b, so that the folded tube portion 2a is flattened, and the folded tube Even if the length (depth of the vertical hole 4) K of the thin portion of the leg portion 2 forming the portion 2a is long, the peak of the double flange portion 2b (projection height from the fastened member B) is kept low. be able to.
[0038]
When the thickness of the fastening member B is thin, long travel distance of the return tube section 2a, but the tip of the caulking punch C ₂ is to be entered to a position lower than the bottom surface 5 of the vertical hole 4, it governs the buckling prevention Since the base 2 of the leg 2 is formed with a small-diameter vertical hole 6 having a depth reaching the head 1 opened at the center of the bottom 5 of the vertical hole 4, the excess synthetic resin portion of the leg 2 is caulked punch As C ₂ enters, as shown in FIG. 11, it can be deformed so as to fill the small-diameter vertical hole 6 and escape to the small-diameter vertical hole 6, which is good despite the fact that the fastened member B is thin. A caulking state is obtained.
[0039]
Therefore, it is possible to perform secure and good caulking by using the synthetic resin rivet A having the same dimensions regardless of whether the member B to be fastened is thick or thin. Therefore, it is not necessary to prepare various kinds of synthetic resin rivets having different lengths of the leg portions 2, and it is economical.
[0040]
Of the cylindrical leg 2, the length K (depth of the vertical hole 4) K of the thin portion located between the tip of the leg and the bottom surface 5 of the vertical hole 4 is the abbreviation of the outer diameter D of the leg 2. The reason for setting it twice is as follows. That is, if the length (depth of the vertical hole 4) K of the thin wall portion is too short, the folded tube portion 2a cannot be formed. If it is too long, the folded tube portion 2a is crushed while expanding outward. This is because the diameter of the double-structured flange portion 2b is too large compared to the head portion 1 in the plastically deformed state.
[0041]
The reason why the inner diameter L ₂ of the small-diameter vertical hole 6 is set to ½ to ３ of the inner diameter L ₁ of the vertical hole 4 is as follows. That is, if the inner diameter L ₂ of the small-diameter vertical hole 6 that opens at the center of the bottom surface 5 of the vertical hole 4 is too large, it cannot serve to prevent buckling by the base side of the leg 2, and the force concentrates during caulking. This is because the base portion of the leg portion 2 is likely to buckle, and if it is too small, the excess synthetic resin portion on the side of the root portion that occurs when the thickness of the fastened member B is thin cannot be escaped to the small diameter vertical hole 6.
[0042]
In the embodiment described above, the caulking punch C ₂ that moves up and down relative to the cradle C ₁ is opposite to the case where the cradle C 2 is fixed and only the caulking punch C ₂ moves up and down. This includes the case where the caulking punch C ₂ is fixed and only the cradle C ₁ moves up and down, and the case where both the cradle C ₁ and the caulking punch C ₂ move up and down (move toward and away from each other). Further, in the illustrated example, the caulking punch C ₂ is disposed above the cradle C ₁ so that the head 1 of the synthetic resin rivet A comes down, and the tip of the leg 2 is pressed from above. It is also possible to perform caulking by reversing these vertical relationships.
[0043]
【The invention's effect】
Since the present invention has the above-described configuration, even if the member to be fastened is a soft material such as a cloth such as cardboard or jeans, stable caulking is possible, and the length of the leg portion is small. Using a fixed synthetic resin rivet, it is possible to perform secure and good caulking regardless of whether the fastening member is thick or thin. Since it is not necessary to prepare several kinds of synthetic resin rivets having different lengths, there are advantages such as being economical.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a synthetic resin rivet according to the present invention.
FIG. 2 is a longitudinal side view for explaining a method of caulking the synthetic resin rivet of FIG. 1 to a thick member to be fastened.
FIG. 3 is a longitudinal sectional side view in the state of caulking.
FIG. 4 is a side view of the synthetic resin rivet in the state of FIG.
FIG. 5 is a longitudinal side view in a state where caulking is completed.
6 is a longitudinal side view for explaining a method of caulking the synthetic resin rivet of FIG. 1 to a thin member to be fastened. FIG.
FIG. 7 is a vertical side view in the state of caulking.
FIG. 8 is a side view of the synthetic resin rivet in the state of FIG.
FIG. 9 is a vertical sectional side view in the state of caulking.
FIG. 10 is a side view of the synthetic resin rivet in the state of FIG.
FIG. 11 is a longitudinal side view in a state where caulking is completed.
FIG. 12 is a longitudinal sectional view for explaining a conventional example.
FIG. 13 is a longitudinal sectional view for explaining a conventional example.
[Explanation of symbols]
A ... Synthetic resin rivet, B ... Fastened member, 1 ... Head, 2 ... Leg part, 2a ... Folded cylinder part, 2b ... Double flange part, 4 ... Vertical hole, 5 ... Bottom face, 6 ... Small diameter vertical hole.

Claims

A synthetic resin rivet composed of a head and a cylindrical leg, and a small-diameter vertical hole having a depth reaching the head opening at the bottom center of the vertical hole is formed on the base side of the leg, In the state where the tip is bent outward and folded, it is configured so that the elastic restoring force acts inward in the radial direction at the opening end of the vertical hole in the leg, and it is crushed while expanding the folded cylinder outward Te, and configured to plastically deform the state forming the flange portion of the double structure, and, said the extra synthetic resin parts of the legs are configured to deform to fill the small diameter longitudinal bore Synthetic resin rivets.

The length of the thin part located between a leg part tip and the bottom face of a vertical hole among cylindrical leg parts is substantially twice as long as the outer diameter of a leg part. Synthetic resin rivets.

The synthetic resin rivet according to claim 1 or 2, wherein the inner diameter of the small-diameter vertical hole is 1/2 to 1/3 of the internal diameter of the vertical hole.

The leg portion of the synthetic resin rivet comprising a head portion and a cylindrical leg portion and having a small-diameter vertical hole having a depth reaching the head portion opened at the center of the bottom surface of the vertical hole is formed on the base side of the leg portion. First, the tip of the leg is resisted against elastic restoring force by inserting it through the hole formed in the fastening member and pressing the tip of the leg in the axial direction while supporting the surface of the head. Te folded by curved outwardly, with and tip has an annular hollow portion abuts against the outer surface of the leg, the elastic restoring force of the radially inwardly to form a folded cylindrical portion shaped to act Then, the folded tube portion is pushed and moved to the head side along the outer surface of the leg portion until the tip of the folded tube portion comes into contact with the fastened member, and then the folded tube portion is expanded outward. crushed by plastic deformation, excess synthetic resin parts of the legs deform so as to fill the small diameter longitudinal bore Allowed, caulking method of a synthetic resin rivet, characterized in that so as to sandwich the workpieces between the flange portion and the head portion of the double structure.