JP2004183869A

JP2004183869A - Suspension coil spring for automobile, and strut type suspension device provided with the suspension coil spring

Info

Publication number: JP2004183869A
Application number: JP2002355188A
Authority: JP
Inventors: Shinsuke Okura; 伸介大倉; Kouji Gotou; 交司後藤
Original assignee: Chuo Hatsujo KK; Chuo Spring Co Ltd
Current assignee: Chuo Hatsujo KK; Chuo Spring Co Ltd
Priority date: 2002-12-06
Filing date: 2002-12-06
Publication date: 2004-07-02

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension coil spring for an automobile comprising a curvature coil spring properly adjusted to prevent a drum part from getting in contact with peripheral parts while securing a desired spring reaction axis when installed on a strut type suspension device. <P>SOLUTION: Curvature quantity δ at the drum part of the curvature coil spring 5x is adjusted. Pitch of a lower seat winding 5a is adjusted in such a way that the lower seat surface 5a is inclined toward a lower seat 4 by a third prescribed angle γ in such a direction that axial length on the inside of curvature becomes short in a free state. Pitch of an upper seat winding 5b is adjusted in such a way that an upper seat surface 5b is inclined to an upper seat 3 by a fourth prescribed angle (γ roughly similar to the third prescribed angle, desirably) in such a direction that axial length on the inside of curvature becomes short in a free state. A compression coil spring 5 of this constitution is installed on the strut type suspension device, for example. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車のストラット型懸架装置に好適な自動車用懸架コイルばね、及びこの懸架コイルばねを備えたストラット型懸架装置に係る。
【０００２】
【従来の技術】
従来より、自動車の車体懸架に圧縮コイルばねが供されており、一般的に圧縮コイルばねはそのコイル軸とばね反力の方向が一致するように設計されている。
自動車用懸架装置に関しては、種々の形式のものが知られているが、車輪の位置決め用の支柱（ストラット）としてショックアブソーバ（緩衝器）を利用したストラット型懸架装置が普及している。このストラット型懸架装置においては、荷重入力軸とストラット軸との間のずれが不可避であるため、ストラットに曲げモーメントが発生し、ストラットのガイド部及びピストン部に作用する横力によってショックアブソーバとしての円滑な摺動作動が阻害される。これを防止するため、例えば円筒状の圧縮コイルばねのコイル軸をストラット軸に対してオフセットさせて曲げモーメントを相殺する技術が利用されている。
【０００３】
自動車用懸架装置の一層の小型化が要請される今日においては、通常の円筒状圧縮コイルばねを用いストラット及びその支持機構の改良を加えるだけでは、路面荷重によってストラットに発生する曲げモーメントを打ち消すことは困難である。従って、圧縮コイルばねの横力を積極的に増大させ、この圧縮コイルばねをストラット型懸架装置に適用することが必要となる。然し乍ら、汎用のコイルばねでは所望の横力を付与することは容易ではない。
【０００４】
この点に鑑み、下記の特許文献１には、簡単な構造で、ストラット型懸架装置への装着時にストラットに対して所望の横力を適切に付与し得る自動車用懸架コイルばねが提案されている。即ち、上側座と下側座との間に圧縮コイルばねを圧縮可能に配置する自動車用懸架コイルばねに関し、圧縮コイルばねのコイル軸が自由状態において実質的に所定の曲率で湾曲するように圧縮コイルばねを形成すると共に、圧縮コイルばねの自由状態において湾曲内側の軸方向長さが短くなる方向に、下側座に着座する圧縮コイルばねの下側座面が下側座に対して所定角度傾斜するように、圧縮コイルばねの下側座巻のピッチを設定し、及び／又は、圧縮コイルばねの自由状態において湾曲外側の軸方向長さが短くなる方向に、上側座に着座する圧縮コイルばねの上側座面が上側座に対して所定角度傾斜するように、圧縮コイルばねの上側座巻のピッチを設定するように構成されている。これにより、従前の懸架装置に対し特に変更を加えることなく、上記の圧縮コイルばねを組み付けるだけで、ばね反力軸が上側座の略中心を通るように適切に支持することができると共に、ストラットに対して所望の横力を適切に付与し、円滑な緩衝作動を確保することができる。
【０００５】
【特許文献１】
特開２０００−１０４７７２号公報
【０００６】
【発明が解決しようとする課題】
上記の特許文献１に記載の自動車用懸架コイルばね（以下、湾曲コイルばねという）によれば、ばね反力軸を適切に調整することができるが、胴部（中間部）が湾曲しているので、装着対象車両によっては、例えば図８に示すように湾曲コイルばねＣＳの胴部の膨出側が周辺部品（例えば車体のフェンダＦＤ等）に接触するおそれがある。尚、図８は湾曲コイルばねＣＳを模式的に記載したもので、一点鎖線で示すばね反力軸ＲＡｐが形成されるように設定されている。この湾曲コイルばねＣＳによれば、ばね反力軸ＲＡｐは所望の位置に設定されているが、湾曲コイルばねＣＳの取付状態（初期圧縮状態）で、その胴部がフェンダＦＤに接触する位置関係にある。
【０００７】
上記のような干渉を回避するためには、湾曲コイルばねＣＳにおける胴部の膨出量（湾曲量）を減らす必要があるが、そうすると、ばね反力軸ＲＡｐを所望の位置に設定することができなくなる。従って、このように湾曲コイルばねの胴部に対し厳格な寸法調整が要請される場合には、湾曲量以外のパラメータを調整することによって、ばね反力軸ＲＡｐを所望の位置に設定し得るように構成することが必要とされる。
【０００８】
そこで、本発明は、コイル軸が湾曲した圧縮コイルばねをストラット型懸架装置に装着するときに、所望のばね反力軸を確保しつつ、圧縮コイルばねの胴部が周辺部品に接触しないように適切に調整した形状を有する自動車用懸架コイルばねを提供することを課題とする。
【０００９】
また、本発明は、コイル軸が湾曲した圧縮コイルばねを、所望のばね反力軸を確保しつつ、胴部が周辺部品に接触しないように適切な形状に調整すると共に、適切な位置関係で装着し得るストラット型懸架装置を提供することを別の課題とする。
【００１０】
【課題を解決するための手段】
上記の課題を解決するため、本発明は請求項１に記載のように、上側座と下側座との間に圧縮コイルばねを圧縮可能に配置する自動車用懸架コイルばねであって、前記圧縮コイルばねのコイル軸が自由状態において実質的に所定の曲率で湾曲するように前記圧縮コイルばねを形成すると共に、前記圧縮コイルばねの自由状態において湾曲内側の軸方向長さが短くなる方向に、前記下側座に着座する前記圧縮コイルばねの下側座面が前記下側座に対して第１の所定角度傾斜するように、前記圧縮コイルばねの下側座巻のピッチを設定し、及び／又は、前記圧縮コイルばねの自由状態において湾曲外側の軸方向長さが短くなる方向に、前記上側座に着座する前記圧縮コイルばねの上側座面が前記上側座に対して第２の所定角度傾斜するように、前記圧縮コイルばねの上側座巻のピッチを設定した自動車用懸架コイルばねにおいて、前記圧縮コイルばねの胴部の湾曲量を調整すると共に、前記圧縮コイルばねの自由状態において湾曲内側の軸方向長さが短くなる方向に、前記下側座に着座する前記圧縮コイルばねの下側座面が前記下側座に対して第３の所定角度傾斜するように、前記圧縮コイルばねの下側座巻のピッチを調整し、且つ、前記圧縮コイルばねの自由状態において湾曲内側の軸方向長さが短くなる方向に、前記上側座に着座する前記圧縮コイルばねの上側座面が前記上側座に対して前記第４の所定角度傾斜するように、前記圧縮コイルばねの上側座巻のピッチを調整することとしたものである。尚、上記の圧縮コイルばねの胴部の湾曲量の調整は、例えば基本構成の胴部の湾曲量に対し所定量増加するように設定される。
【００１１】
上記の自動車用懸架コイルばねにおいて、請求項２に記載のように、前記第３の所定角度と前記第４の所定角度は略同一の角度に設定することが望ましい。尚、前記上側座巻及び下側座巻を、ピッグテール巻きとし、上側座及び下側座をピッグテール側の座巻に合致する形状とすることにより、装着時の位置決めが容易となる。
【００１２】
また、本発明のストラット型懸架装置は、請求項３に記載のように、車体にストラットの上端を支持すると共に、前記ストラットに固定する下側座と前記車体に支持する上側座との間に、前記ストラットを囲繞するように圧縮コイルばねを配置し、前記ストラットを介して前記車体に車輪を支持するストラット型懸架装置において、前記圧縮コイルばねのコイル軸が自由状態において実質的に所定の曲率で湾曲するように前記圧縮コイルばねを形成すると共に、前記圧縮コイルばねの自由状態において湾曲内側の軸方向長さが短くなる方向に、前記下側座に着座する前記圧縮コイルばねの下側座面が前記下側座に対して第１の所定角度傾斜するように、前記圧縮コイルばねの下側座巻のピッチを設定し、及び／又は、前記圧縮コイルばねの自由状態において湾曲外側の軸方向長さが短くなる方向に、前記上側座に着座する前記圧縮コイルばねの上側座面が前記上側座に対して第２の所定角度傾斜するように、前記圧縮コイルばねの上側座巻のピッチを設定し、且つ、前記圧縮コイルばねに対する前記下側座及び前記上側座の支持傾斜角度に応じて前記圧縮コイルばねの胴部の湾曲量を調整した自動車用懸架コイルばねを、前記圧縮コイルばねの取付状態において湾曲外側の軸方向長さが短くなる方向に、前記下側座を第３の所定角度傾斜させて支持し、且つ、前記圧縮コイルばねの取付状態において湾曲外側の軸方向長さが短くなる方向に、前記上側座を前記第４の所定角度傾斜させて支持し、前記湾曲したコイル軸の内側が前記車体の内側となるように保持することとしたものである。
【００１３】
上記のストラット型懸架装置においては、請求項４に記載のように、前記第３の所定角度と前記第４の所定角度は略同一の角度に設定することが望ましい。更に、前記圧縮コイルばねの前記上側座巻及び下側座巻を、ピッグテール巻きとし、上側座及び下側座をピッグテール側の座巻に合致する形状とすれば、装着時の位置決めが容易となる。
【００１４】
【発明の実施の形態】
以下、本発明の実施形態を図面を参照して説明する。図１の（Ｂ）は本発明の自動車用懸架コイルばねに供する圧縮コイルばねの一実施形態を示すもので、この圧縮コイルばね５をストラット型懸架装置（以下、単に懸架装置という）に組付けると図２に示す状態となる。尚、図１の（Ｂ）においては、圧縮コイルばね５の基本構成である図１の（Ａ）に示す後述の湾曲コイルばね５ｘに対応する部分を二点鎖線で示している。また、図２においては、圧縮コイルばね５の上端を支持する部分を除き、懸架装置の構成を二点鎖線で示している。
【００１５】
先ず、図２を参照して懸架装置の全体構成を説明すると、車体１にストラット２の上端が弾性的に支持されると共に、上側座３が車体１に支持され、ストラット２の胴部に下側座４が固定されている。これら上側座３と下側座４との間に、ストラット２を囲繞するように圧縮コイルばね５が配置されている。ストラット２の下端はナックル６に固定され、ナックル６はロアアーム７を介して車体１にピボット結合されている。而して、ナックル６に軸支される車輪８はストラット２及び圧縮コイルばね５を介して車体１に支持されると共に、ロアアーム７を介して車体１に支持されている。
【００１６】
ストラット２はシリンダ２ａと、このシリンダ２ａ内に摺動自在に支持されたロッド２ｂを備え、これらによってショックアブソーバが構成されている。ロッド２ｂの上端はストラットマウント１０を介して車体１に取り付けられ、シリンダ２ａの下端がナックル６に取り付けられる。本実施形態のストラットマウント１０は荷重経路分離型となっており、圧縮コイルばね５のばね反力軸が上側座面の略中心を通るように設計されている。
【００１７】
上記の構成になる懸架装置においては、図２に示すように、荷重入力軸ＡＡとばね反力軸ＲＡは一致せず、ストラット２のストラット軸ＳＡと荷重入力軸ＡＡとは角度θ１をなすのに対し、ストラット軸ＳＡとばね反力軸ＲＡとは角度θ２をなしている。尚、ＬＡはロアアーム７の軸、ＫＡはキングピン軸を表す。上記荷重入力軸ＡＡとストラット軸ＳＡの不一致に起因し、ストラット２のシリンダ２ａとロッド２ｂとの間に摺動抵抗が生じ得るが、この摺動抵抗は後述するように圧縮コイルばね５の付勢力によって発生が抑えられ、ロッド２ｂの円滑な摺動作動が確保される。
【００１８】
ここで、一般的に、圧縮コイルばねを圧縮したときに発生するばね反力はコイル軸に沿うことはなく、図３に示すように、ｘ−ｙ平面に投影した成分が横力（ＳＦで示す）と呼ばれる。そして、ｙ軸から時計方向の角度（図３にθで示す）が横力ＳＦの向きを表し、横力方向と呼ばれる。尚、図３は、下側座巻及び上側座巻の座巻中心軸と胴部のコイル軸が一致する（図３のｚ軸）ように形成された圧縮コイルばねのモデルＭＳ（以下、単に圧縮コイルばねＭＳという）を示すものである。従って、図１及び図２は、図３のｘ，ｙ，ｚ軸の３次元座標における圧縮コイルばねＭＳと同様に配置したときの圧縮コイルばね５を、ｙ−ｚ面に投影した側面図を示している。
【００１９】
本実施形態の圧縮コイルばね５は図１の（Ｂ）に示すように構成されており、先ず、図１の（Ａ）を参照して基本構成となる湾曲コイルばね５ｘについて説明する。この湾曲コイルばね５ｘは、前掲の特許文献１に記載の圧縮コイルばねと同様に構成されており、下側座巻５ａｘ及び上側座巻５ｂｘの座巻中心、即ち下側座面ＬＳｘの中心と上側座面ＵＳｘの中心を通る軸ＣＥ（以下、座巻中心軸ＣＥという）をｚ軸とし、所定方向（車体の左右方向）をｙ軸とするｙ−ｚ面上において、湾曲コイルばね５ｘのコイル軸ＣＡｘが所定の曲率半径Ｒｘで湾曲するように形成されており、その胴部（中間部）は湾曲量δの初期胴曲がりを有する。尚、コイル軸ＣＡｘは、同一方向で複数の曲率を以って実質的に所定の曲率で湾曲するように形成してもよい。あるいは、複数の直線軸を連結して実質的に所定の曲率で湾曲したコイル軸となるように構成してもよい。
【００２０】
そして、湾曲コイルばね５ｘの自由状態において、湾曲コイルばね５ｘの湾曲内側（図１（Ａ）の左側）の軸方向長さが短くなる方向（図１（Ａ）の時計方向）に、下側座面ＬＳｘが下側座４に対して所定角度α傾斜するように、下側座巻５ａｘのピッチが設定されている。また、湾曲コイルばね５ｘの湾曲外側（図１（Ａ）の右側）の軸方向長さが短くなる方向（図１（Ａ）の時計方向）に、上側座面ＵＳｘが上側座３に対して所定角度β傾斜するように、上側座巻５ｂｘのピッチが設定されている。
【００２１】
この場合において、下側座面ＬＳｘと下側座４との関係は相対的であり、図１（Ａ）では下側座面ＬＳｘが水平で、これに対し下側座４が所定角度α傾斜する関係にあるが、逆に図１（Ａ）において下側座４を水平とし、下側座面ＬＳｘが下側座４に対して所定角度α傾斜する関係としてもよい。同様に、上側座面ＵＳｘと上側座３との関係も相対的であり、図１（Ａ）において、上側座３が傾斜し、この傾斜面に対し上側座面ＵＳｘが所定角度β傾斜する関係としてもよいし、逆に上側座面ＵＳｘが傾斜し、上側座３が上側座面ＵＳに対して所定角度β傾斜する関係としてもよい。尚、図２の懸架装置における上側座３と下側座４は支持面が平行となるように配設されており、これに応じて上記の相対関係を充足するように、圧縮コイルばねが形成される。
【００２２】
図１（Ａ）においては、湾曲コイルばね５ｘの自由状態において、下側座面ＬＳｘが下側座４に対して図１の時計方向に所定角度α傾斜するように下側座巻５ａｘのピッチが設定されると共に、上側座面ＵＳｘが上側座３に対して図１（Ａ）の時計方向に所定角度β傾斜するように、上側座巻５ｂｘのピッチが設定されているが、下側座巻５ａｘ及び上側座巻５ｂｘのいずれか一方側のみに対してピッチ設定を行なうこととしてもよい。即ち、この態様のほか、図示は省略するが、第２の態様として、コイル軸ＣＡｘが湾曲するように形成し、下側座巻５ａｘのピッチのみを、湾曲コイルばね５ｘの自由状態において下側座面ＬＳｘが下側座４に対して所定角度傾斜するように設定する態様がある。そして、第３の態様（図示省略）として、コイル軸ＣＡｘが湾曲するように形成し、上側座巻５ｂｘのピッチのみを、湾曲コイルばね５ｘの自由状態において上側座面ＵＳｘが上側座３に対して所定角度傾斜するように設定する態様がある。
【００２３】
ここで、コイル軸がｙ軸方向に膨出するように湾曲した圧縮コイルばね（湾曲コイルばね５ｘに相当）に対し、一方の側面の軸方向長さが短くなる方向に圧縮した場合、即ち、ｙ−ｚ面上でコイル軸が湾曲した湾曲コイルばねを、図３に示す圧縮コイルばねＭＳと同様の位置に配置し、その上側座面及び下側座面をｘ軸回りに、ｘ軸の＋側から原点をみたとき反時計方向となる方向に、夫々α度及びβ度回転させた場合における実験結果について説明する。
【００２４】
図４は、ｙ−ｚ面上でコイル軸が湾曲した湾曲コイルばね（湾曲量δ）を所定高さに圧縮した状態で上側座面及び下側座面をｘ軸回りに、ｘ軸の＋側から原点をみたとき反時計方向となる方向に、夫々α度及びβ度回転させた場合のばね反力軸の変化を実線で示すもので、破線は通常の（胴曲り無しの）圧縮コイルばねにおける同様の場合のばね反力軸の変化を示す。図４において、図３のｘ軸回りの回転角（傾斜角度α、β）を反時計方向に増加したときのばね反力軸の変化を表している（図４の矢印はα、βの増加方向を示す）。尚、ばね反力軸は上側座面及び下側座面に作用するばね反力の着力点を結ぶ軸である。
【００２５】
図４から以下の事項が明らかとなる。即ち、（１）湾曲量δの初期胴曲がりによって、ばね反力軸はｙ方向（胴曲がり方向）に平行移動する。（２）上側座面及び下側座面の傾斜角度α、βの図３の反時計方向への増加により、ばね反力軸のｙ方向の傾きが増加する。換言すれば、傾斜角度α、βの増加に応じて湾曲コイルばねに対する横力が増加する。（３）上側座面及び下側座面の傾斜角度α、βの増加に伴い、上側座面におけるばね反力の着力点は、湾曲コイルばねでは実線で示すように上側座面の中心（図４のｚ軸）に近づくのに対し、通常の圧縮コイルばねでは破線で示すように上側座面の中心から遠ざかる。これとは逆に、ｙ−ｚ面上でコイル軸が湾曲した湾曲コイルばねを所定高さに圧縮した状態で上側座面及び下側座面をｘ軸回りに、ｘ軸の＋側から原点をみたとき時計方向となる方向に回転させた場合には、上側座面及び下側座面の傾斜角度α、βの時計方向への増加により、ばね反力軸のｙ方向の傾きが減少する、即ち湾曲コイルばねに対する横力が減少することになる。
【００２６】
尚、図５は、ｙ−ｚ面上で湾曲コイルばねを所定高さに圧縮した状態で、上側座面及び下側座面を夫々図３のｘ軸回りに、ｘ軸の＋側から原点をみたとき反時計方向となる方向に、夫々α、β度回転させる場合において、傾斜角度αあるいはβを増加させたときの横力の変化を示すもので、実線は湾曲コイルばねを示し、破線は通常の圧縮コイルばねを示す。図５から明らかなように、何れのコイルばねもαあるいはβの増加に応じて横力が増加するが、その差は殆どない。
【００２７】
そして、本実施形態の圧縮コイルばね５においては、図１の（Ｂ）に示すように、２点鎖線で示す湾曲コイルばね（図１（Ａ）の湾曲コイルばね５ｘに相当）に対し、胴部の湾曲量がΔδだけ増加するように調整される（δ＋Δδ）と共に、圧縮コイルばね５の自由状態において湾曲内側の軸方向長さが短くなる方向に、下側座面ＬＳが下側座４に対して第３の所定角度γ傾斜するように、下側座巻５ａのピッチが調整され、且つ、圧縮コイルばね５の自由状態において湾曲内側の軸方向長さが短くなる方向に、上側座面ＵＳが上側座３に対して第４の所定角度傾斜するように、上側座巻５ｂのピッチが調整される。この第４の所定角度は本実施形態では第３の所定角度と略同一のγに設定される。即ち、下側座面ＬＳ及び上側座面ＵＳが同一の所定角度γで湾曲外側に開く方向に、下側座巻５ａ及び上側座巻５ｂのピッチが調整される。
【００２８】
換言すれば、本実施形態の圧縮コイルばね５は、図２に示すように上側座３と下側座４との間に介装したときに、圧縮コイルばね５を所定高さに圧縮した状態で上側座及び下側座を、図３に示すｘ軸の＋側から原点をみたとき反時計方向となる方向に、夫々α、β度回転させた場合と同様の状態となるように、図１（Ａ）の曲率Ｒｘ（湾曲量δ）及び傾斜角度α、β（図１（Ａ）では時計方向の回転角）が設定され、上側座巻５ｂ及び下側座巻５ａのピッチが設定されている。これにより、図１の（Ａ）に示すように形成された湾曲コイルばね５ｘを、上側座３と下側座４との間に介装（圧縮）して取付状態とすると、湾曲コイルばね５ｘに対し上側座巻及び下側座巻を、図３のｘ軸の＋側から原点をみたときに反時計方向となる方向に傾斜させた場合と同様の効果を奏する。
【００２９】
また、図１の（Ｂ）に示すように、胴部の湾曲量がΔδだけ増加するように調整される（δ＋Δδ）と共に、上側座と下側座との間に介装したときに、圧縮コイルばね５を所定高さに圧縮した状態で下側座を、図３に示すｘ軸の＋側から原点をみたとき反時計方向となる方向に、下側座面ＬＳの下側座４に対する調整用の所定角度γ（図１（Ｂ）では時計方向の回転角）が設定され、下側座巻５ａのピッチが調整されている。同時に、上側座３と下側座４との間に介装したときに、圧縮コイルばね５を所定高さに圧縮した状態で上側座を、図３に示すｘ軸の＋側から原点をみたとき時計方向となる方向に、上側座面ＵＳの上側座３に対する調整用の所定角度γ（図１（Ｂ）では反時計方向の回転角）が設定され、上側座巻５ｂのピッチが調整されている。これにより、図１の（Ｂ）に示すように形成された圧縮コイルばね５を、上側座３と下側座４との間に介装（圧縮）して取付状態とすると、圧縮コイルばね５に対し下側座巻５ａを、図３のｘ軸の＋側から原点をみたときに反時計方向となる方向に傾斜させ、且つ、上側座巻５ｂを、図３のｘ軸の＋側から原点をみたときに時計方向となる方向に傾斜させた場合と同様の効果を奏する。
【００３０】
上記の構成になる圧縮コイルばねの具体例のシミュレーション結果について図６を参照して説明する。先ず、ベースサンプルは湾曲コイルばね５ｘとし、その下側座面の傾斜角度αが３．０°で、上側座面の傾斜角度βは０°（即ち、前述の第２の態様）で、胴部の湾曲量δが３ｍｍのものとした。このベースサンプルの緒元として、ばね定数：１６．７Ｎ／ｍｍ、総巻数：７．０巻、自由長：３３８．９ｍｍ、コイル外径：８９．５ｍｍ、線径：９．４ｍｍとし、取付荷重：２２３６Ｎとした。そして、第３及び第４の所定角度たる角度γを２．５°とした場合（サンプル１という）及び５．０°とした場合（サンプル２という）において、これらのサンプルを取付状態に圧縮したときの湾曲量が基本構成の湾曲コイルばね５ｘの圧縮時の湾曲量δと同じ値となるように、湾曲量δに対する増加量Δδを設定した。この結果生ずるばね反力軸（荷重軸）及び外形の変化を図６に示している。
【００３１】
従って、角度γが２．５°のサンプル１は、湾曲コイルばね５ｘの上側座面の傾斜角度αが５．５°となり、下側座面の傾斜角度βは−２．５°（αと反対方向に傾斜）となる。このとき、自由状態での胴部の湾曲量の増加量Δδは２ｍｍに設定され、従って自由状態におけるサンプル１の胴部の湾曲量は５ｍｍとなる。同様に、角度γが５．０°のサンプル２は、湾曲コイルばね５ｘの上側座面の傾斜角度αが８．０°となり、下側座面の傾斜角度βは−５．０°（αと反対方向）となる。このとき、自由状態での胴部の湾曲量の増加量Δδは４ｍｍに設定され、従って自由状態におけるサンプル２の胴部の湾曲量は７ｍｍとなる。
【００３２】
図６は、上記のベースサンプル、サンプル１及びサンプル２を取付状態に圧縮したときのばね反力軸（荷重軸）と外形を示すもので、サンプル１及びサンプル２は、ばね反力軸が車体外側（図６の右側）方向に平行移動しているのに対し、胴部における同方向への湾曲量が略同じとなっており、湾曲量は相対的に抑えられている。従って、サンプル１及びサンプル２のばね反力軸をベースサンプルのばね反力軸と一致するように配置させると、胴部の外側は相対的に中心軸方向に移動することになる。尚、図６においてベースサンプルの荷重軸を点線（細かい破線）で示し、その外形のデータを丸で示す。また、サンプル１の荷重軸を破線で示し、その外形のデータを四角形で示す。そして、サンプル２の荷重軸を実線で示し、その外形のデータを三角形で示す。
【００３３】
而して、図８の湾曲コイルばねＣＳと対比して本実施形態の圧縮コイルばねを模式的に表し５ｅとした図７に示すように、圧縮コイルばね５ｅのばね反力軸ＲＡｅは、ばね反力軸ＲＡｐと同じ所望の位置に設定された場合には、図６から明らかなように胴部が相対的に中心軸方向に移動することになる。即ち、胴部は周辺部品（例えばフェンダＦＤ）から退避した位置関係となるので、胴部が周辺部品に接触することはない。このように、本実施形態によれば、所望のばね反力軸ＲＡｅを確保し得ると共に、圧縮コイルばねの胴部が周辺部品に接触しないように適切な形状に調整することができる。
【００３４】
尚、本発明のストラット型懸架装置を構成する場合には、図１（Ａ）の湾曲コイルばね５ｘにおける胴部の湾曲量を、装着対象の上側座及び下側座との最終的な相対的位置関係に応じて予め調整しておき（δ＋Δδ）、図１（Ｂ）に示す所定角度γの調整に代えて、上側座及び下側座を図１（Ｂ）の傾斜方向と反対方向に所定角度γ傾斜させることとしてもよい。即ち、本発明の他の実施形態として、図１（Ｂ）の下側座４及び上側座３の支持傾斜角度に応じて湾曲コイルばね５ｘの胴部の湾曲量を調整し、このばねの取付状態において湾曲外側の軸方向長さが短くなる方向に、下側座４を所定角度γ傾斜させて支持し、且つ、取付状態において湾曲外側の軸方向長さが短くなる方向に、上側座３を所定角度γ傾斜させて支持し、湾曲したコイル軸の内側が車体の内側となるように保持することとすれば、相対的な位置関係が、図１（Ｂ）の圧縮コイルばね５を上側座３と下側座４との間に介装したときと同様の関係となる。
【００３５】
更に、上側座巻５ｂ及び下側座巻５ａを、ピッグテール巻きとし、上側座３及び下側座４をピッグテール側の座巻に合致する形状とすれば、装着時の位置決めが容易となる。
【００３６】
【発明の効果】
本発明は上述のように構成されているので以下の効果を奏する。即ち、請求項１及び２に係る自動車用懸架コイルばねにおいては、湾曲コイルばねの胴部の湾曲量を調整すると共に、自由状態において湾曲内側の軸方向長さが短くなる方向に、下側座面が下側座に対して第３の所定角度傾斜するように、下側座巻のピッチを調整し、且つ、自由状態において湾曲内側の軸方向長さが短くなる方向に、上側座面が上側座に対して第４の所定角度（望ましくは第３の所定角度と略同一）傾斜するように、上側座巻のピッチを調整することとしているので、ストラット型懸架装置に装着するときに、所望のばね反力軸を確保しつつ、胴部が周辺部品に接触しないように適切に調整した湾曲コイルばねの自動車用懸架コイルばねを提供することができる。
【００３７】
また、請求項３及び４に記載のストラット型懸架装置は、装着対象の下側座及び上側座の支持傾斜角度に応じて湾曲コイルばねの胴部の湾曲量を調整した自動車用懸架コイルばねを、取付状態において湾曲外側の軸方向長さが短くなる方向に、下側座を第３の所定角度傾斜させて支持し、且つ、取付状態において湾曲外側の軸方向長さが短くなる方向に、上側座を第４の所定角度傾斜（望ましくは第３の所定角度と略同一）させて支持し、湾曲したコイル軸の内側が車体の内側となるように保持する構成とされているので、所望のばね反力軸を確保しつつ、胴部が周辺部品に接触しないように、湾曲コイルばねを適切な形状に調整すると共に、適切な位置関係で装着することができる。
【図面の簡単な説明】
【図１】本発明の自動車用懸架コイルばねの一実施形態に供する圧縮コイルばね及び基本構成の湾曲コイルばねを示す側面図である。
【図２】本発明の一実施形態に係る圧縮コイルばねを自動車用懸架装置に装着した状態を示す正面図である。
【図３】上側座面及び下側座面の傾斜がばね反力に及ぼす影響を実験するための圧縮コイルばねのモデルを示す斜視図である。
【図４】本発明の一実施形態に係る圧縮コイルばねに関し、ｙ−ｚ面上で圧縮コイルばねを所定高さに圧縮した状態で上側座面及び下側座面をｘ軸回りに、ｘ軸の＋側から原点をみたとき反時計方向に回転させた場合におけるばね反力軸の変化を示すグラフである。
【図５】本発明の一実施形態に係る圧縮コイルばねに関し、ｙ−ｚ面上で圧縮コイルばねを所定高さに圧縮した状態で上側座面及び下側座面をｘ軸回りに、ｘ軸の＋側から原点をみたとき反時計方向に回転させた場合における回転角度に応じた横力の変化を示すグラフである。
【図６】本発明の一実施形態に係る圧縮コイルばねに関し、その具体例のシミュレーション結果によるばね反力軸及び胴部の外形の変化を示すグラフである。
【図７】本発明の一実施形態に係る圧縮コイルばねの取付状態を模式的に示す側面図である。
【図８】模式的に記載した従来の湾曲コイルばねの取付状態を示す側面図である。
【符号の説明】
１車体，２ストラット，３上側座，４下側座，
５圧縮コイルばね，５ｘ湾曲コイルばね，６ナックル，
７ロアアーム，８車輪，１０ストラットマウント，
ＵＳ，ＵＳｘ上側座面，ＬＳ，ＬＳｘ下側座面[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle suspension coil spring suitable for a vehicle strut suspension, and a strut suspension including the suspension coil spring.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a compression coil spring is provided on a vehicle body suspension of an automobile, and the compression coil spring is generally designed so that its coil axis and a direction of a spring reaction force coincide with each other.
Various types of vehicle suspensions are known, and strut type suspensions using shock absorbers (buffers) as struts for positioning wheels have become widespread. In this strut type suspension device, since a displacement between the load input shaft and the strut shaft is inevitable, a bending moment is generated in the strut, and the lateral force acting on the guide portion and the piston portion of the strut causes the strut to function as a shock absorber. Smooth sliding operation is hindered. In order to prevent this, for example, a technique of offsetting a coil axis of a cylindrical compression coil spring with respect to a strut axis to cancel a bending moment is used.
[0003]
In today's demand for more compact suspension systems for automobiles, simply improving the strut and its supporting mechanism using a normal cylindrical compression coil spring can negate the bending moment generated on the strut due to road surface load. It is difficult. Therefore, it is necessary to positively increase the lateral force of the compression coil spring and apply this compression coil spring to a strut type suspension. However, it is not easy to apply a desired lateral force with a general-purpose coil spring.
[0004]
In view of this point, Patent Literature 1 listed below proposes a suspension coil spring for a vehicle that has a simple structure and can appropriately apply a desired lateral force to a strut when mounted on a strut-type suspension device. . That is, the present invention relates to a suspension coil spring for a vehicle in which a compression coil spring is compressably disposed between an upper seat and a lower seat, and the compression coil spring is compressed so that the coil axis of the compression coil spring is substantially bent at a predetermined curvature in a free state. Along with forming the coil spring, the lower seating surface of the compression coil spring seated on the lower seat in a direction in which the axial length of the inside of the curve becomes shorter in the free state of the compression coil spring is at a predetermined angle with respect to the lower seat. The pitch of the lower end turn of the compression coil spring is set so as to be inclined, and / or the compression coil seated on the upper seat in a direction in which the axial length of the outside of the curve becomes shorter in the free state of the compression coil spring. The configuration is such that the pitch of the upper end turns of the compression coil spring is set so that the upper seat surface of the spring is inclined at a predetermined angle with respect to the upper seat. Thus, by simply assembling the above-described compression coil spring without particularly changing the conventional suspension device, the spring reaction force axis can be appropriately supported so as to pass through substantially the center of the upper seat, and the strut can be appropriately supported. , A desired lateral force is appropriately applied to the tire, and a smooth cushioning operation can be ensured.
[0005]
[Patent Document 1]
JP 2000-104772 A
[0006]
[Problems to be solved by the invention]
According to the vehicle suspension coil spring (hereinafter referred to as a curved coil spring) described in Patent Document 1, the spring reaction axis can be appropriately adjusted, but the trunk (intermediate portion) is curved. Therefore, depending on the mounting target vehicle, for example, as shown in FIG. 8, the bulging side of the body of the curved coil spring CS may come into contact with peripheral components (for example, a fender FD of the vehicle body). FIG. 8 schematically shows the curved coil spring CS, which is set so as to form a spring reaction force axis RAp indicated by a chain line. According to the curved coil spring CS, the spring reaction force axis RAp is set at a desired position. However, when the curved coil spring CS is mounted (in an initial compression state), the positional relationship where the body contacts the fender FD. It is in.
[0007]
In order to avoid the above-described interference, it is necessary to reduce the bulging amount (curvature amount) of the trunk portion in the curved coil spring CS. However, in such a case, the spring reaction force axis RAp may be set to a desired position. become unable. Therefore, when strict dimensional adjustment is required for the body of the curved coil spring, the spring reaction force axis RAp can be set to a desired position by adjusting parameters other than the amount of bending. Is required.
[0008]
Therefore, the present invention is to secure a desired spring reaction force axis when mounting a compression coil spring having a curved coil axis on a strut type suspension device, and to prevent the body of the compression coil spring from contacting peripheral components. An object of the present invention is to provide a suspension coil spring for an automobile having a shape adjusted appropriately.
[0009]
In addition, the present invention adjusts a compression coil spring having a curved coil axis to an appropriate shape so that a trunk portion does not contact peripheral components while securing a desired spring reaction force axis, and in an appropriate positional relationship. It is another object to provide a strut-type suspension that can be mounted.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a suspension coil spring for a vehicle, wherein a compression coil spring is arranged between an upper seat and a lower seat in a compressible manner. The compression coil spring is formed so that the coil axis of the coil spring is substantially bent at a predetermined curvature in the free state, and the axial length of the inside of the curve is reduced in the free state of the compression coil spring, Setting a pitch of a lower winding of the compression coil spring such that a lower seating surface of the compression coil spring seated on the lower seat is inclined at a first predetermined angle with respect to the lower seat; and And / or an upper seating surface of the compression coil spring seated on the upper seat in a direction in which the axial length of the outside of the curve becomes shorter in a free state of the compression coil spring is a second predetermined angle with respect to the upper seat. In front of you to incline In a vehicle suspension coil spring in which the pitch of the upper winding of the compression coil spring is set, the amount of curvature of the body of the compression coil spring is adjusted, and the axial length of the inside of the curve in the free state of the compression coil spring is adjusted. The pitch of the lower end turns of the compression coil spring such that the lower seat surface of the compression coil spring seated on the lower seat is inclined at a third predetermined angle with respect to the lower seat in the shorter direction. In the free state of the compression coil spring, the upper seating surface of the compression coil spring seated on the upper seat in the direction in which the axial length of the inside of the curve becomes shorter in the free state of the compression coil spring is the third position relative to the upper seat. The pitch of the upper winding of the compression coil spring is adjusted so as to incline at a predetermined angle of 4. The adjustment of the bending amount of the body of the compression coil spring is set so as to be increased by a predetermined amount with respect to the bending amount of the body of the basic configuration, for example.
[0011]
In the above suspension coil spring for an automobile, it is preferable that the third predetermined angle and the fourth predetermined angle are set to be substantially the same angle. It should be noted that the upper and lower end windings are pig tail windings, and the upper and lower seats are shaped to match the end windings on the pig tail side, thereby facilitating positioning during mounting.
[0012]
Further, the strut type suspension device of the present invention, as described in claim 3, supports the upper end of the strut on the vehicle body, and between the lower seat fixed to the strut and the upper seat supported on the vehicle body. A strut-type suspension device that arranges a compression coil spring so as to surround the strut and supports a wheel on the vehicle body through the strut, wherein the coil axis of the compression coil spring has a substantially predetermined curvature when the coil axis is free. The compression coil spring is formed so as to be curved at a lower position, and the compression coil spring is seated on the lower seat in a direction in which the axial length of the inside of the curve becomes shorter in a free state of the compression coil spring. Setting the pitch of the lower end turn of the compression coil spring so that the surface is inclined at a first predetermined angle with respect to the lower seat, and / or In the state, the compression coil spring is so arranged that the upper seat surface of the compression coil spring seated on the upper seat is inclined at a second predetermined angle with respect to the upper seat in the direction in which the axial length of the outside of the curve becomes shorter. A suspension coil spring for a vehicle, wherein the pitch of the upper end turn is set, and the amount of curvature of the body of the compression coil spring is adjusted in accordance with the support inclination angles of the lower seat and the upper seat with respect to the compression coil spring. The lower seat is supported by being inclined at a third predetermined angle in a direction in which the axial length of the outside of the curve becomes shorter in the attached state of the compression coil spring, and curved in the attached state of the compression coil spring. The upper seat is supported by being inclined at the fourth predetermined angle in a direction in which the outer axial length becomes shorter, and the upper seat is held so that the inside of the curved coil shaft is the inside of the vehicle body. so That.
[0013]
In the above-mentioned strut-type suspension device, it is preferable that the third predetermined angle and the fourth predetermined angle are set to substantially the same angle. Furthermore, if the upper end turn and the lower end turn of the compression coil spring are pigtail turns, and the upper and lower seats are shaped to match the end turns on the pig tail side, positioning at the time of mounting is facilitated. .
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1B shows an embodiment of a compression coil spring used for a suspension coil spring for a vehicle according to the present invention, and this compression coil spring 5 is assembled to a strut type suspension device (hereinafter simply referred to as a suspension device). And the state shown in FIG. In FIG. 1B, a portion corresponding to a later-described curved coil spring 5x shown in FIG. 1A, which is a basic configuration of the compression coil spring 5, is indicated by a two-dot chain line. In FIG. 2, the configuration of the suspension device is indicated by a two-dot chain line except for a portion that supports the upper end of the compression coil spring 5.
[0015]
First, the overall structure of the suspension device will be described with reference to FIG. 2. The upper end of the strut 2 is elastically supported by the vehicle body 1, the upper seat 3 is supported by the vehicle body 1, and the lower part of the strut 2 is The side seat 4 is fixed. A compression coil spring 5 is arranged between the upper seat 3 and the lower seat 4 so as to surround the strut 2. The lower end of the strut 2 is fixed to a knuckle 6, and the knuckle 6 is pivotally connected to the vehicle body 1 via a lower arm 7. Thus, the wheel 8 supported by the knuckle 6 is supported by the vehicle body 1 via the strut 2 and the compression coil spring 5, and is supported by the vehicle body 1 via the lower arm 7.
[0016]
The strut 2 includes a cylinder 2a and a rod 2b slidably supported in the cylinder 2a, and these constitute a shock absorber. The upper end of the rod 2b is attached to the vehicle body 1 via the strut mount 10, and the lower end of the cylinder 2a is attached to the knuckle 6. The strut mount 10 of the present embodiment is of a load path separated type, and is designed so that a spring reaction force axis of the compression coil spring 5 passes through substantially the center of the upper seat surface.
[0017]
In the suspension having the above configuration, as shown in FIG. 2, the load input axis AA does not coincide with the spring reaction force axis RA, and the strut axis SA of the strut 2 and the load input axis AA form an angle θ1. On the other hand, the strut axis SA and the spring reaction force axis RA form an angle θ2. LA denotes the axis of the lower arm 7 and KA denotes the kingpin axis. Due to the disagreement between the load input shaft AA and the strut shaft SA, a sliding resistance may occur between the cylinder 2a and the rod 2b of the strut 2. The generation is suppressed by the force, and the smooth sliding operation of the rod 2b is ensured.
[0018]
Here, generally, the spring reaction force generated when the compression coil spring is compressed does not follow the coil axis. As shown in FIG. 3, the component projected on the xy plane has a lateral force (SF). Shown). An angle clockwise from the y-axis (indicated by θ in FIG. 3) indicates the direction of the lateral force SF, and is called a lateral force direction. FIG. 3 shows a model MS (hereinafter simply referred to as a simple model) of a compression coil spring formed such that the center axis of the lower end turn and the upper end turn and the coil axis of the body coincide (the z axis in FIG. 3). (Referred to as a compression coil spring MS). Therefore, FIGS. 1 and 2 are side views in which the compression coil spring 5 when arranged similarly to the compression coil spring MS in the three-dimensional coordinates of the x, y, and z axes in FIG. 3 is projected on the yz plane. Is shown.
[0019]
The compression coil spring 5 according to the present embodiment is configured as shown in FIG. 1B. First, a curved coil spring 5x having a basic configuration will be described with reference to FIG. This curved coil spring 5x is configured similarly to the compression coil spring described in Patent Document 1 mentioned above, and is formed between the center of the lower end turn 5ax and the upper end turn 5bx, that is, the center of the lower seat surface LSx. The axis CE passing through the center of the upper seat surface USx (hereinafter referred to as the end turn center axis CE) is defined as the z-axis, and a predetermined direction (the left-right direction of the vehicle body) is defined as a y-axis on the yz plane. The coil axis CAx is formed so as to be curved with a predetermined radius of curvature Rx, and its body (intermediate part) has an initial body bending with a bending amount δ. The coil axis CAx may be formed so as to be substantially curved at a predetermined curvature with a plurality of curvatures in the same direction. Alternatively, a configuration may be employed in which a plurality of linear axes are connected to form a coil axis substantially curved at a predetermined curvature.
[0020]
When the bending coil spring 5x is in the free state, the bending coil spring 5x moves downward (in the clockwise direction in FIG. 1A) in the direction in which the axial length of the inside of the bending (left side in FIG. 1A) decreases. The pitch of the lower end turns 5ax is set so that the seat surface LSx is inclined at a predetermined angle α with respect to the lower seat 4. In addition, the upper seat surface USx is positioned with respect to the upper seat 3 in a direction (clockwise direction in FIG. 1A) in which the axial length of the bending coil spring 5x on the outer side of the curve (right side in FIG. 1A) becomes shorter. The pitch of the upper end turns 5bx is set so as to be inclined by a predetermined angle β.
[0021]
In this case, the relationship between the lower seating surface LSx and the lower seating 4 is relative. In FIG. 1A, the lower seating surface LSx is horizontal, and the lower seating surface LSx is inclined by a predetermined angle α. 1A, the lower seat 4 may be horizontal and the lower seat surface LSx may be inclined at a predetermined angle α with respect to the lower seat 4. Similarly, the relationship between the upper seat surface USx and the upper seat 3 is also relative. In FIG. 1A, the upper seat 3 is inclined, and the upper seat surface USx is inclined at a predetermined angle β with respect to the inclined surface. Alternatively, the upper seat surface USx may be inclined, and the upper seat 3 may be inclined at a predetermined angle β with respect to the upper seat surface US. The upper seat 3 and the lower seat 4 in the suspension of FIG. 2 are arranged so that their support surfaces are parallel to each other. Accordingly, a compression coil spring is formed so as to satisfy the above-described relative relationship. Is done.
[0022]
In FIG. 1A, the pitch of the lower end turns 5ax is such that the lower seat surface LSx is inclined at a predetermined angle α clockwise in FIG. 1 with respect to the lower seat 4 in the free state of the curved coil spring 5x. Is set, and the pitch of the upper turn 5bx is set so that the upper seat surface USx is inclined at a predetermined angle β in the clockwise direction in FIG. The pitch may be set for only one of the winding 5ax and the upper end winding 5bx. That is, in addition to this aspect, although not shown, as a second aspect, the coil axis CAx is formed to be curved, and only the pitch of the lower end turns 5ax is set to the lower side in the free state of the curved coil spring 5x. There is a mode in which the seating surface LSx is set so as to be inclined at a predetermined angle with respect to the lower seat 4. Then, as a third mode (not shown), the coil axis CAx is formed to be curved, and only the pitch of the upper end turns 5bx is set such that the upper seat surface USx is in relation to the upper seat 3 in the free state of the curved coil spring 5x. There is a mode in which the angle is set to a predetermined angle.
[0023]
Here, when a compression coil spring (corresponding to a curved coil spring 5x) that is curved so that the coil axis expands in the y-axis direction is compressed in a direction in which the axial length of one side surface is shortened, A curved coil spring whose coil axis is curved on the yz plane is arranged at the same position as the compression coil spring MS shown in FIG. 3, and its upper and lower seating surfaces are rotated around the x-axis. A description will be given of experimental results in the case of rotating α degrees and β degrees in directions counterclockwise when the origin is viewed from the + side.
[0024]
FIG. 4 shows the upper and lower seating surfaces around the x-axis in a state where a curved coil spring (bending amount δ) in which the coil axis is bent on the yz plane is compressed to a predetermined height, and the x-axis + The solid line shows the change in the axis of the spring reaction force when rotated by α and β degrees in the counterclockwise direction when viewed from the side from the origin, and the broken line is a normal (no body bending) compression coil. 3 shows the change in the spring reaction axis in a similar case for a spring. FIG. 4 shows a change in the spring reaction force axis when the rotation angle (tilt angle α, β) about the x-axis in FIG. 3 is increased in the counterclockwise direction (arrows in FIG. 4 indicate increases in α, β). Direction). Incidentally, the spring reaction force axis is an axis connecting the contact points of the spring reaction force acting on the upper seat surface and the lower seat surface.
[0025]
The following matters become clear from FIG. That is, (1) due to the initial bending of the bending amount δ, the spring reaction force axis moves in parallel in the y-direction (the bending direction of the body). (2) Increasing the inclination angles α and β of the upper seat surface and the lower seat surface in the counterclockwise direction in FIG. 3 increases the inclination of the spring reaction force axis in the y direction. In other words, the lateral force on the curved coil spring increases as the inclination angles α and β increase. (3) As the inclination angles α and β of the upper seat surface and the lower seat surface increase, the point of application of the spring reaction force on the upper seat surface is, as shown by the solid line in the curved coil spring, the center of the upper seat surface (see FIG. (Z axis of FIG. 4), whereas a normal compression coil spring moves away from the center of the upper seating surface as shown by the broken line. Conversely, the upper and lower seating surfaces are rotated around the x-axis in a state in which a curved coil spring whose coil axis is curved on the yz plane is compressed to a predetermined height. When the clockwise rotation is viewed, the inclination angles α and β of the upper seat surface and the lower seat surface increase in the clockwise direction, so that the inclination of the spring reaction force axis in the y direction decreases. That is, the lateral force on the curved coil spring is reduced.
[0026]
FIG. 5 shows a state in which the upper and lower seating surfaces are respectively rotated around the x-axis in FIG. 3 from the + side of the x-axis in a state where the curved coil spring is compressed to a predetermined height on the yz plane. When the angle of rotation is α and β degrees, respectively, in the counterclockwise direction when viewed, the change in the lateral force when the inclination angle α or β is increased, the solid line indicates a curved coil spring, and the broken line Indicates a normal compression coil spring. As is clear from FIG. 5, the lateral force of any of the coil springs increases as α or β increases, but there is almost no difference.
[0027]
In the compression coil spring 5 according to the present embodiment, as shown in FIG. 1B, the body is different from the curved coil spring indicated by the two-dot chain line (corresponding to the curved coil spring 5x in FIG. 1A). The amount of curvature of the portion is adjusted so as to increase by Δδ (δ + Δδ), and the lower seat surface LS is moved in the direction in which the axial length of the inner side of the curve decreases in the free state of the compression coil spring 5. The pitch of the lower end turn 5a is adjusted so as to be inclined by a third predetermined angle γ with respect to the upper seat, so that the axial length of the inside of the curve becomes shorter in the free state of the compression coil spring 5. The pitch of the upper end turns 5b is adjusted such that the surface US is inclined by a fourth predetermined angle with respect to the upper side seat 3. In the present embodiment, the fourth predetermined angle is set to substantially the same γ as the third predetermined angle. That is, the pitches of the lower end turn 5a and the upper end turn 5b are adjusted in such a direction that the lower seat LS and the upper seat US open outward at the same predetermined angle γ.
[0028]
In other words, when the compression coil spring 5 of the present embodiment is interposed between the upper seat 3 and the lower seat 4, as shown in FIG. The upper and lower seats are rotated by α and β degrees in directions counterclockwise when viewed from the + side of the x-axis shown in FIG. 1A, the curvature Rx (the amount of curvature δ) and the inclination angles α and β (the clockwise rotation angle in FIG. 1A) are set, and the pitches of the upper end turn 5b and the lower end turn 5a are set. ing. Thereby, when the curved coil spring 5x formed as shown in FIG. 1A is interposed (compressed) between the upper seat 3 and the lower seat 4 to be mounted, the curved coil spring 5x On the other hand, the same effect as in the case where the upper end turn and the lower end turn are inclined in the counterclockwise direction when the origin is viewed from the + side of the x-axis in FIG.
[0029]
Also, as shown in FIG. 1B, the amount of curvature of the trunk is adjusted to increase by Δδ (δ + Δδ), and when the body is interposed between the upper seat and the lower seat, the compression is reduced. In a state where the coil spring 5 is compressed to a predetermined height, the lower seat is placed on the lower seat 4 in a counterclockwise direction when the origin is viewed from the + side of the x-axis shown in FIG. A predetermined angle γ for adjustment (clockwise rotation angle in FIG. 1B) is set, and the pitch of the lower end turns 5a is adjusted. At the same time, when interposed between the upper seat 3 and the lower seat 4, the origin is viewed from the + side of the x-axis shown in FIG. 3 with the compression coil spring 5 compressed to a predetermined height. A predetermined angle γ (a counterclockwise rotation angle in FIG. 1B) for adjustment of the upper seat surface US with respect to the upper seat 3 is set in the clockwise direction, and the pitch of the upper end turns 5b is adjusted. ing. Accordingly, when the compression coil spring 5 formed as shown in FIG. 1B is interposed (compressed) between the upper seat 3 and the lower seat 4 to be mounted, the compression coil spring 5 In contrast, the lower end turn 5a is inclined in a counterclockwise direction when the origin is viewed from the + side of the x-axis in FIG. 3, and the upper end turn 5b is tilted from the + side of the x-axis in FIG. The same effect as in the case of inclining in the clockwise direction when viewing the origin is obtained.
[0030]
A simulation result of a specific example of the compression coil spring having the above configuration will be described with reference to FIG. First, the base sample is a curved coil spring 5x, the inclination angle α of the lower seat surface is 3.0 °, the inclination angle β of the upper seat surface is 0 ° (that is, the above-described second embodiment), The curvature δ of the portion was 3 mm. The specifications of this base sample were as follows: spring constant: 16.7 N / mm, total number of turns: 7.0, free length: 338.9 mm, coil outer diameter: 89.5 mm, wire diameter: 9.4 mm, mounting load : 2236N. Then, when the third and fourth predetermined angles γ were set to 2.5 ° (referred to as sample 1) and 5.0 ° (referred to as sample 2), these samples were compressed into an attached state. The amount of increase Δδ with respect to the amount of bending δ was set such that the amount of bending at this time had the same value as the amount of bending δ when the bending coil spring 5x having the basic configuration was compressed. FIG. 6 shows the resulting change in the spring reaction axis (load axis) and outer shape.
[0031]
Therefore, in the sample 1 in which the angle γ is 2.5 °, the inclination angle α of the upper seat surface of the curved coil spring 5x is 5.5 °, and the inclination angle β of the lower seat surface is −2.5 ° (α and Inclined in the opposite direction). At this time, the increase amount Δδ of the bending amount of the trunk in the free state is set to 2 mm, and therefore, the bending amount of the trunk of the sample 1 in the free state is 5 mm. Similarly, in the sample 2 having the angle γ of 5.0 °, the inclination angle α of the upper seat surface of the curved coil spring 5x is 8.0 °, and the inclination angle β of the lower seat surface is −5.0 ° (α And the opposite direction). At this time, the increase amount Δδ of the bending amount of the torso in the free state is set to 4 mm, and therefore, the bending amount of the torso of the sample 2 in the free state is 7 mm.
[0032]
FIG. 6 shows the spring reaction force axis (load axis) and the outer shape when the above-mentioned base sample, sample 1 and sample 2 are compressed in the mounted state. While the body moves parallel to the outside (the right side in FIG. 6), the amount of bending in the same direction on the trunk is substantially the same, and the amount of bending is relatively suppressed. Therefore, when the spring reaction axes of the sample 1 and the sample 2 are arranged so as to coincide with the spring reaction axis of the base sample, the outside of the body moves relatively in the direction of the central axis. In FIG. 6, the load axis of the base sample is indicated by a dotted line (fine broken line), and the data of the outer shape is indicated by a circle. The load axis of Sample 1 is indicated by a broken line, and the data of the outer shape is indicated by a square. The load axis of Sample 2 is indicated by a solid line, and the data of its outer shape is indicated by a triangle.
[0033]
Thus, as shown in FIG. 7, which schematically shows the compression coil spring of this embodiment in comparison with the curved coil spring CS of FIG. 8 and shows 5e, the spring reaction force axis RAe of the compression coil spring 5e is When it is set at the same desired position as the reaction force axis RAp, the trunk moves relatively in the direction of the central axis as is apparent from FIG. That is, since the body has a positional relationship retracted from the peripheral component (for example, the fender FD), the body does not contact the peripheral component. As described above, according to the present embodiment, a desired spring reaction force axis RAe can be secured, and the compression coil spring can be adjusted to an appropriate shape so as not to come into contact with peripheral components.
[0034]
When configuring the strut type suspension device of the present invention, the bending amount of the trunk in the bending coil spring 5x of FIG. Adjustment is made in advance in accordance with the positional relationship (δ + Δδ). Instead of adjusting the predetermined angle γ shown in FIG. 1 (B), the upper seat and the lower seat are set in a direction opposite to the inclination direction of FIG. 1 (B). The angle γ may be inclined. That is, as another embodiment of the present invention, the amount of bending of the trunk of the bending coil spring 5x is adjusted according to the support inclination angles of the lower seat 4 and the upper seat 3 in FIG. The lower seat 4 is supported by being inclined at a predetermined angle γ in the direction in which the axial length of the outside of the curve decreases in the state, and the upper seat 3 in the direction in which the axial length of the outside of the curve decreases in the attached state. Is supported at a predetermined angle γ and the inside of the curved coil axis is located inside the vehicle body, the relative positional relationship is such that the compression coil spring 5 of FIG. The relationship is the same as when interposed between the seat 3 and the lower seat 4.
[0035]
Furthermore, if the upper end turn 5b and the lower end turn 5a are pigtailed, and the upper seat 3 and the lower end 4 are shaped to match the end turn on the pig tail side, positioning at the time of mounting becomes easy.
[0036]
【The invention's effect】
The present invention has the following effects because it is configured as described above. That is, in the vehicle suspension coil spring according to the first and second aspects, the amount of bending of the body of the bending coil spring is adjusted, and the lower seat is disposed in a direction in which the axial length of the inside of the bending becomes shorter in the free state. The pitch of the lower end winding is adjusted so that the surface is inclined at a third predetermined angle with respect to the lower seat, and the upper seating surface is oriented in a direction in which the axial length of the inside of the curve becomes shorter in a free state. Since the pitch of the upper end turn is adjusted so as to be inclined at a fourth predetermined angle (preferably substantially the same as the third predetermined angle) with respect to the upper seat, when the upper seat is mounted on the strut type suspension device, It is possible to provide a vehicle suspension coil spring of a curved coil spring that is appropriately adjusted so that a trunk portion does not contact peripheral components while securing a desired spring reaction force axis.
[0037]
Further, the strut type suspension device according to claims 3 and 4 is a vehicle suspension coil spring in which the amount of bending of the body of the bending coil spring is adjusted according to the support inclination angles of the lower seat and the upper seat to be mounted. In the mounting state, the lower seat is supported by being inclined at a third predetermined angle in the direction in which the axial length of the outside of the curve becomes shorter in the attached state, and in the direction in which the axial length of the outside of the curve becomes shorter in the attached state, The upper seat is supported by being inclined at a fourth predetermined angle (preferably substantially the same as the third predetermined angle), and is held so that the inside of the curved coil axis is inside the vehicle body. The curved coil spring can be adjusted to an appropriate shape and mounted in an appropriate positional relationship so that the trunk does not contact the peripheral parts while securing the spring reaction force axis of the spring.
[Brief description of the drawings]
FIG. 1 is a side view showing a compression coil spring and a curved coil spring having a basic configuration provided in an embodiment of a vehicle suspension coil spring of the present invention.
FIG. 2 is a front view showing a state in which the compression coil spring according to one embodiment of the present invention is mounted on a vehicle suspension.
FIG. 3 is a perspective view showing a model of a compression coil spring for testing the effect of the inclination of the upper seat surface and the lower seat surface on the spring reaction force.
FIG. 4 relates to a compression coil spring according to an embodiment of the present invention, with the compression coil spring compressed to a predetermined height on the yz plane, and the upper and lower seating surfaces around the x-axis; It is a graph which shows the change of the spring reaction force axis | shaft when rotating in a counterclockwise direction when the origin is seen from the + side of an axis | shaft.
FIG. 5 relates to a compression coil spring according to an embodiment of the present invention, in which the upper and lower seating surfaces are rotated around the x axis while the compression coil spring is compressed to a predetermined height on the yz plane, 9 is a graph showing a change in a lateral force according to a rotation angle when rotated in a counterclockwise direction when the origin is viewed from the + side of the axis.
FIG. 6 is a graph showing a change in a spring reaction force axis and an outer shape of a body portion according to a simulation result of a specific example of the compression coil spring according to one embodiment of the present invention.
FIG. 7 is a side view schematically showing an attached state of the compression coil spring according to one embodiment of the present invention.
FIG. 8 is a side view showing an attached state of a conventional curved coil spring schematically described.
[Explanation of symbols]
1 body, 2 struts, 3 upper seat, 4 lower seat,
5 compression coil spring, 5x curved coil spring, 6 knuckle,
7 lower arms, 8 wheels, 10 strut mounts,
US, USx Upper seating surface, LS, LSx Lower seating surface

Claims

An automotive suspension coil spring in which a compression coil spring is compressably disposed between an upper seat and a lower seat, such that a coil axis of the compression coil spring is bent at a substantially predetermined curvature in a free state. While forming the compression coil spring, the lower seat surface of the compression coil spring seated on the lower seat in a direction in which the axial length of the inside of the curve becomes shorter in the free state of the compression coil spring is the lower side. The pitch of the lower end turn of the compression coil spring is set so as to be inclined at a first predetermined angle with respect to the seat, and / or the axial length of the outer side of the curve in the free state of the compression coil spring is short. The pitch of the upper end turns of the compression coil spring is set such that the upper seat surface of the compression coil spring seated on the upper seat is inclined at a second predetermined angle with respect to the upper seat in the following direction. Suspension The compression coil, which adjusts the amount of curvature of the body of the compression coil spring and seats on the lower seat in a direction in which the axial length of the inside of the curve decreases in the free state of the compression coil spring. The pitch of the lower end turns of the compression coil spring is adjusted so that the lower seat surface of the spring is inclined at a third predetermined angle with respect to the lower seat, and the compression coil spring bends in a free state. The upper side of the compression coil spring such that an upper seat surface of the compression coil spring seated on the upper seat is inclined at the fourth predetermined angle with respect to the upper seat in a direction in which an inner axial length becomes shorter. A suspension coil spring for an automobile, wherein the pitch of the end turns is adjusted.

The suspension coil spring for a vehicle according to claim 1, wherein the third predetermined angle and the fourth predetermined angle are set to be substantially the same.

While supporting the upper end of the strut on the vehicle body, a compression coil spring is arranged between the lower seat fixed to the strut and the upper seat supported on the vehicle body so as to surround the strut, and via the strut In a strut type suspension device for supporting wheels on the vehicle body, the compression coil spring is formed so that a coil axis of the compression coil spring is substantially curved at a predetermined curvature in a free state, and the compression coil spring is free of force. In the state, in the direction in which the axial length of the inside of the curve becomes shorter, the lower seat surface of the compression coil spring seated on the lower seat is inclined at a first predetermined angle with respect to the lower seat, Setting the pitch of the lower end turn of the compression coil spring, and / or setting the upper seat in a direction in which the axial length of the outer side of the curve becomes shorter in the free state of the compression coil spring; The pitch of the upper winding of the compression coil spring is set so that the upper seating surface of the compression coil spring to be seated is inclined at a second predetermined angle with respect to the upper seat, and the lower coil relative to the compression coil spring is set. An automotive suspension coil spring in which the amount of curvature of the body of the compression coil spring is adjusted in accordance with the support inclination angle of the side seat and the upper seat, the axial length of the outside of the curve in the mounted state of the compression coil spring is short. The lower seat is supported by being inclined at a third predetermined angle in the direction in which the upper coil is attached to the fourth coil in the direction in which the axial length of the outside of the curve becomes shorter in the mounted state of the compression coil spring. A strut-type suspension device which is supported by being inclined at a predetermined angle, and held such that the inside of the curved coil axis is inside the vehicle body.

The strut-type suspension device according to claim 3, wherein the third predetermined angle and the fourth predetermined angle are set to substantially the same angle.