JP2005022424A

JP2005022424A - Suspension device for vehicle

Info

Publication number: JP2005022424A
Application number: JP2003135073A
Authority: JP
Inventors: Shinichiro Oki; 真一郎沖
Original assignee: Mitsubishi Motors Corp
Current assignee: Mitsubishi Motors Corp
Priority date: 2003-05-08
Filing date: 2003-05-13
Publication date: 2005-01-27
Anticipated expiration: 2023-05-13
Also published as: CN100390004C; JP4225113B2; TWI243763B; TW200426049A; CN1550397A

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension device for a vehicle which can increase the durability of an elastic member which supports a cross member. <P>SOLUTION: This suspension device adopts a constitution in which elastic members 18 and 19 are combined. In this case, the elastic member 18 elastically supports the cross member 1 at a location being the same as the cross member 1 or closer to the front end of the vehicle than the cross section as elastically supporting members 17a and 17b which elastically support the cross member 1 to the vehicle body side. The elastic member 19 elastically supports the cross member 1 at a location in the longitudinal direction of the vehicle body being approximately the same as a coil spring 14 which is incorporated with trailing arms 4a and 4b. Thus, loads which are inputted in the cross member 1 from rear wheels 10 through the trailing arms 4a and 4b are approximately evenly inputted to both elastic members 18 and 19. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、サスペンションアームを支えるクロスメンバが複数の弾性部材で車体側にマウントされる車両のサスペンション装置に関する。
【０００２】
【従来の技術】
自動車（車両）の後輪を独立懸架するサスペンション装置には、トレーリングアーム（サスペンションアーム）を用いて、後輪（車輪）を上下に揺動可能に懸架する構造がある。
【０００３】
このトレーリングアーム式のサスペンション装置は、通常、車体の幅方向に延びるクロスメンバをフレームとして用い、このクロスメンバの車幅方向両側に、車両後方へ延びるトレーリングアームを配置して、このトレーリングアームの車両前方側の端部をクロスメンバに上下方向に揺動自在に支持し、トレーリングアームの車両後方側の端部に後輪を回転自在に支持させ、トレーリングアームと車体側との間にスプリングを介在させる構造が用いられる。つまり、同構造は、後輪が荷重を受けると、トレーリングアームが上下に揺動変位する。
【０００４】
こうしたトレーリングアーム式のサスペンション装置では、衝撃力や振動が車体へ伝わるのを抑えるために、クロスメンバの端部を車体下面に弾性支持させることが行われている。近時では、荷重負担の軽減や乗り心地の向上のために、クロスメンバの各端部を、車両前後方向に並ぶ弾性部材を用いて、車体側に弾性支持させることが行われている。そのほとんどは、クロスメンバの端部近傍とそれから近い車幅方向内側の地点にそれぞれ弾性部材を設けて、車両前後方向両側からクロスメンバの端部を支持するという、左右４点の弾性支持で、クロスメンバを車体側にマウントさせる構造が採用されている（例えば特許文献１を参照）。
【０００５】
【特許文献１】
特開２００２−１２７９３５号公報
【０００６】
【発明が解決しようとする課題】
ところで、トレーリングアームを用いたサスペンション装置は、車両への組付けを考慮して各部を定めると、構造上、クロスメンバの上下方向の荷重入力中心、すなわち後輪（車輪）からトレーリングアームを介してクロスメンバへ入力される上下方向の荷重の入力中心は、そのほとんどがクロスメンバを弾性支持している弾性部材のうち、車両後方側の弾性部材の近くに定められる。
【０００７】
このため、クロスメンバを弾性支持する弾性部材のうち、車両後方側の弾性部材の荷重負担が大きく、車両後方側の弾性部材の耐久性だけが偏って低下するおそれがあった。
【０００８】
そこで、本発明の目的は、クロスメンバを支える弾性部材の耐久性の向上が図れる車両のサスペンション装置を提供することにある。
【０００９】
【課題を解決するための手段】
請求項１に記載の発明は、前記目的を達成するために、クロスメンバを車体側に弾性支持する弾性支持部材として、クロスメンバよりも車両前方側の位置で弾性支持する第１弾性部材と、サスペンションアームに組付くスプリングと略同じ車体前後方向の位置で弾性支持する第２弾性部材とを組み合わせた構成を採用した。
【００１０】
同構成により、車輪からサスペンションアームを介してクロスメンバに入力される荷重が、第１、第２弾性部材に対して略均等に入力されるようになる。
【００１１】
すなわち、サスペンションアームを支持するスプリングは、車両後方側から車体側へ荷重が入力される部位でもある。
【００１２】
このスプリングでの荷重入力を考慮すると、スプリングが有る位置と略同じ車両後方側の位置は、クロスメンバに作用する上下方向の荷重の入力中心を挟んで、クロスメンバよりも車両前方側の位置に配置される第１弾性部材に対して、荷重のバランスがとれやすいうえ、かつ確実に前記の荷重入力中心から遠ざけることが可能な地点であることがわかる。
【００１３】
つまり、この位置に設けられる車両後方側の第２弾性部材は、クロスメンバに作用する上下方向の荷重の入力中心から確実に遠ざかる地点で、それも荷重が車両前後方向で第１弾性部材と均等にバランスしやすい地点に配置されることになる。
【００１４】
それ故、車輪からサスペンションアームに入力される荷重は、第１弾性部材と第２弾性部材との双方に略均等に入力されるようになり、耐久性を損なう要因となる荷重負担の偏りが改善される。
【００１５】
請求項２に記載の発明は、前記目的に加え、さらに車輪から入力される上下方向の荷重が第１弾性部材と第２弾性部材との双方に均等に入力されるよう、上下方向の入力中心から第１弾性部材までの距離と、上下方向の入力中心から第２弾性部材までの距離とを略等しくしたことにある。
【００１６】
請求項３に記載の発明は、特にサスペンションアームの車輪側の支持部と、同じくスプリングの支持部と、同じく車内側の端部が支持される支持部の三つの部位が直線上に並ぶという、クロスメンバの支持する弾性部材の荷重負担が偏りやすいサスペンション装置で顕著に効果が表れるよう、クロスメンバを弾性支持する弾性支持部材には、クロスメンバの端部と同じかそれよりも車両前方側の位置で弾性支持する第１弾性部材と、サスペンションアームに組付くスプリングと略同じ車体前後方向の位置で弾性支持する第２弾性部材とを組み合わせた構成を採用して、車輪側の支持部と車内側の支持部との中間に配置されるスプリングを考慮して車両後方側の第２弾性部材を、クロスメンバの荷重入力中心から確実に遠ざかる地点で、かつ荷重が車両前後方向で均等にバランスしやすい地点に配置して、請求項１のとき同様、車輪から入力される上下方向の荷重が第１弾性部材と第２弾性部材との双方に略均等に入力可能にした。
【００１７】
請求項４に記載の発明は、前記目的に加え、さらに上下方向の荷重負担の偏りの改善に際し、第２弾性部材とサスペンションアームとの干渉を避けるよう、第２弾性部材がサスペンションアームよりも車両内側に配設される構成とした。
【００１８】
請求項５に記載の発明は、前記目的に加え、さらに上下方向の荷重入力に対するクロスメンバのピッチング量を抑えるよう、第１弾性部材と第２弾性部材とに上下方向の荷重が入力される場合の弾性中心を、車内側支持部の近傍に設定して、各弾性部材の弾性中心をクロスメンバの荷重入力中心に近づけ、ピッチングの発生の要因となる両中心の車両前後位置の差を小さくするようにした。
【００１９】
請求項６に記載の発明は、前記目的を達成するために、クロスメンバを車体側に弾性支持する弾性支持部材として、クロスメンバと同じかそれよりも車両前方側の位置で弾性支持する第１弾性部材と、クロスメンバよりも車体後方向側で弾性支持する第２弾性部材とを用い、車輪からサスペンションアームを通じてクロスメンバに入力される上下方向の荷重の入力中心から第１弾性部材までの距離と、入力中心から第２弾性部材までの距離とが略等しくして、車輪から入力される荷重が第１弾性部材と第２弾性部材との両者に略均等に入力されるようにした。
【００２０】
請求項７に記載の発明は、さらに前後における極端な上下方向の荷重の偏りを回避するよう、荷重の入力中心から第１弾性部材までの車両前後方向の距離をＰ、荷重の入力中心から第２弾性部材までの車両前後方向の距離をＱとしたとき
｛（Ｐ＋Ｑ）／２｝×０．７≦Ｐ≦｛（Ｐ＋Ｑ）／２｝×１．３
が満たせるようにした。
【００２１】
請求項８に記載の発明は、さらに実用上クロスメンバのピッチング量が十分に低減されるよう、荷重の入力中心から第１弾性部材までの車両前後方向の距離をＰ、荷重の入力中心から第２弾性部材までの車両前後方向の距離をＱ、第１弾性部材と第２弾性部材の弾性中心から第１弾性部材までの車両前後方向の距離をＵ、荷重の入力中心から弾性中心までの車両前後方向の距離をＴとしたとき
−０．１Ｕ≦Ｔ≦０．１｛（Ｐ＋Ｑ）−Ｕ｝
を満たせるようにした。
【００２２】
【発明の実施の形態】
以下、本発明を図１ないし図３に示す一実施形態にもとづいて説明する。
【００２３】
図１は、本発明を適用した例えば後輪駆動式自動車（車両）又は前輪駆動式自動車（車両）のリヤ側に採用されるトレーリングアーム型サスペンション装置の全体の外観、図２は、同サスペンション装置の平面図、図３は図１中のＡ〜Ａ線から見たサスペンション装置の背面図（なお、デフは除いてある）をそれぞれ示している。
【００２４】
図中１は、トレーリングアーム型サスペンション装置のフレームをなすクロスメンバ、２はクロスメンバ１の中央後方側に配設されたデファレンシャルである。なお、クロスメンバ２、デファレンシャル２は、いずれも車体（図示しない）の下側に配設される部品である。
【００２５】
クロスメンバ１は、例えば中央が車両後方側および車両上方側の双方へ山形状に突き出した車幅方向に沿って延びる筒形部材で形成されている。そして、この中央の山形状部１ａ内に、デファレンシャル２のケース部分が支持され、デファレンシャル２の入力部２ａを車両前方へ臨ませている。なお、３はデファレンシャル２の後端を車体側へ支持させるためのバー状のブラケットである。
【００２６】
またクロスメンバ１の車幅方向両側には、サスペンションアームに相当するトレーリングアーム４ａ，４ｂが左右対称に組付けてある。トレーリングアーム４ａ，４ｂは、勝手反対となる同じ構造でクロスメンバ１に支持させてある。具体的には、両トレーリングアーム４ａ，４ｂは、例えば車両前方側がクロスメンバ１の傾斜部１ｂの形状にならって後退方向に傾斜する辺部５ａ、車両後方側の車幅方向最外側部が頂部５ｂ、車幅方向内側が大きく傾く辺部５ｃとする三角板状部材から形成されている。そして、前端側をなす車体前方に延在する辺部５ａが、後退角を保ったまま、後退方向に傾斜した傾斜部１ｂに上下方向に回動自在に支持させてある。同支持構造には、例えば同辺部５ａを車幅方向外側と、それより車幅方向内側との２つに分岐し、このうちの車外側の端部８ａを車外側の支持部、例えばアームピボット９ａで、傾斜部１ｂの車外側、ここでは最外側となるクロスメンバ１ａの端側に上下方向に回動自在に支持してある。また車内側の端部８ｂは、車内側の支持部、例えばアームピボット９ｂ（片側だけ図示）を介して、傾斜部１ｂの中央寄りの部分に上下方向に回動自在に支持されている。つまり、車内側のアームピボット９ｂは、車外側のアームピボット９ａよりも車両方向側にずれた位置に配置してある。この後退角に沿って配置したアームピボット９ａ，９ｂによって、トレーリングアーム４ａ，４ｂを上下方向に揺動自在に支持させてある。
【００２７】
各トレーリングアーム４ａ，４ｂの車両後端側となる頂部５ｂ側には、後輪１０（図１だけに図示：本願の車輪に相当）が組付く部品、例えばハブ部材１１が回動自在に設けられ、左右の両後輪１０が上下方向に変位可能に支持される構造にしてある。これにより、後輪１０からの上下方向の荷重が、トレーリングアーム４ａ，４ｂを介してクロスメンバ１へ入力されるようにしてある。このときクロスメンバ１へ入力される上下方向の荷重の入力中心（以下、荷重入力中心という）Ｃ１（図２に図示）は、トレーリングアーム４ａ，４ｂの支持構造上、クロスメンバ１の支持部の近く、具体的には車内側に配置されるアームピボッド９ｂの近くを通る線上に定まる。そして、例えば各ハブ部材１１に、デファレンシャル２から車幅方向両側に延びているリアアクスル２ｂが、一対の自在継手、例えば等速ジョイント１３（一方側しか図示せず）を介して連結される。
【００２８】
また各トレーリングアーム４ａ，４ｂの上面の中央には、衝撃緩衝用のスプリング、例えばコイルスプリング１４が縦置きで載せてある。これらコイルスプリング１４は、下端部がトレーリングアーム４ａ，４ｂ上に形成されたスプリング座１４ａ（スプリングを支持する支持部に相当）に支持され、上端部が車体（図示しない）の下面側で支持され、トレーリングアーム４ａ，４ｂを上下方向に弾性支持させている。ここで、コイルスプリング１４は、限られた大きさのトレーリングアーム４ａ，４ｂに配置されるために、構造上、コイルスプリング１４のコイルスプリング座１４ａは、図２に示されるように後輪１０の支持部を構成する例えばハブ部材１１の軸中心となるホイールセンタとなるＷ／Ｃ点と、車内側のアームピボッド９ｂの軸中心となるＧ点とを結ぶ線α上に配置される傾向にある。つまり、本実施形態例のトレーリングアーム型サスペンション装置は、図２に示されるようにハブ部材１１のＷ／Ｃ点、トレーリングアーム側のスプリングコイル端の軸心となるＳ点、車内側のアームピボット９ｂのＧ点が略一直線上に配置される。
【００２９】
各トレーリングアーム４ａ，４ｂの頂部５ｂ側には、車体（図示しない）に支持されるショックアブソーバ１５が連結されていて、トレーリングアーム４ａ，４ｂを伝わる後輪１０からの衝撃や振動が減衰される構造にしてある。なお、１６はスタビライザを示す（例えば中間がクロスメンバ１で支持され、端部がそれぞれトレーリングアーム４ａ，４ｂに連結されるコ字形のバー部材からなる）。
【００３０】
またクロスメンバ１の左右側（車幅方向）には、車体側にクロスメンバ１を弾性支持させる一対の弾性支持部材１７ａ，１７ｂが設けられている。弾性支持部材１７ａ，１７ｂには、クロスメンバ１と同じかあるいはそれよりも車両前方側となる位置に組付く左右一対の弾性部材、ここではクロスメンバ端に車両前方側へ突き出るように設けた左右一対の弾性部材１８と、クロスメンバ１の中央部分に車両後方側に突き出るように設けた左右一対の弾性部材１９とを組み合わせた構造が用いられている。
【００３１】
具体的には、弾性部材１８には、いずれも例えばボルト止めで車体側に支持可能とした弾性変位自在な筒形のブッシュ、例えばゴム材などで形成された弾性ブッシュが用いてある。また例えば車外側のアームピボット９ａを支持するブラケット１２ａには、その一部を車両前方へ突き出させた車体支持側のブラケット部１２ｂが形成されていて、そのブラケット部１２ｂの先端部に上記弾性部材１８が縦向き（軸心が上下方向に配置される向き）で組み付けてある。残る弾性部材１９は、弾性部材１８と同様、例えばボルト止めで車体側に支持可能とした例えばゴム材などで形成された筒形の弾性ブッシュが用いてある。またクロスメンバ１の山形状となっている中央部には、例えばデファレンシャル２の上側を覆い隠すように車両後方へＥ形状に張り出すＥ形のブラケット２０が取着されていて、そのブラケット２０の先端側の左右コーナー部分に対称をなして上記弾性部材１９が縦向き（軸心が上下方向に配置される向き）で組み付けてある。これら弾性部材１９の組付け位置は、トレーリングアーム４ａ，４ｂ上のコイルスプリング１４の取付位置と略同じ位置にしてある。具体的には、図２に示されるように弾性部材１９は、その弾性部材１９の弾性中心Ｒが、コイルスプリング１４のＳ点と略同じ位置となるブラケット２０の地点に組み付けてある。この組み付けにより、弾性部材１９は、車体前後方向においてコイルスプリング１４と略同じ位置に配設させてある。
【００３２】
こうしたクロスメンバ１から車両前方の弾性部材１８と、クロスメンバ１から車両後方の弾性部材１９とにより、弾性部材１８，１９に対する入力荷重の均等化が図れる構造にしている。また同構造に加え、図２に示されるようにクロスメンバ１の荷重入力中心Ｃ１から弾性部材１８までの距離Ｐと、荷重入力中心Ｃ１から弾性部材１９までの距離Ｑとができるだけ等しくなるよう、サスペンション装置の各部を調整させてある。つまり、この調整によって、距離Ｐ，Ｑとを略等しくさせている。また弾性部材１９は、いずれも図２および図３に示されるようにトレーリングアーム４ａ，４ｂよりも車両内側の地点に配置され、揺動するトレーリングアーム４ａ，４ｂとの干渉を避ける構造にもしてある。
【００３３】
また図２に示されるように弾性部材１８，１９間に設定される弾性ブッシュの上下方向の弾性中心Ｃ２は、弾性部材１８のばね定数の調整、弾性部材１９のばね定数の調整によって、クロスメンバ１の荷重入力中心Ｃ１との距離Ｔをできる限り減少させている。そして、この調整により、弾性中心Ｃ２を荷重入力中心Ｃ１の近傍に設定させている。
【００３４】
このように構成されたトレーリングアーム型サスペンション装置は、左右の後輪１０が上下方向の荷重を受けると、トレーリングアーム４ａ，４ｂがアームピボット９ａ，９ｂを支点に上下に揺動しながら、後輪１０からの荷重がクロスメンバ１に入力される。そして、トレーリングアーム４ａ，４ｂの振れが、リングアームコイルスプリング１４、ショックアブソーバ１５により抑えられる。
【００３５】
このとき、後輪１０から入力される上下方向の荷重は、トレーリングアーム４ａ，４ｂを支持する両アームピボット９ａ，９ｂを伝わってクロスメンバ１へ入力されるとともに、トレーリングアーム４ａ，４ｂの中間をシーソーのように支えるコイルスプリング１４を通じて車体側へに伝えられる。
【００３６】
このとき、コイルスプリング１４が設置されている位置と略同じ車両後方側の位置は、クロスメンバ１の荷重入力中心Ｃ１を挟んで、クロスメンバ１と同じかそれよりも車両前方側に配置されている弾性部材１８（荷重入力中心Ｃ１から離れた車両前方側の弾性部材１８）に対して、荷重のバランスがとれやすく、荷重入力中心Ｃ１から遠ざかる地点であることがわかる。つまり、コイルスプリング１４と略同じ位置は、トレーリングアーム４ａ，４ｂに加わる荷重を分散させるのに好適な位置である。
【００３７】
ここで、弾性部材１９は、この位置に設けてあるから、同弾性部材１９には、トレーリングアーム４ａ，４ｂからの荷重が集中せずに分散して入力される。
【００３８】
それ故、後輪１０からトレーリングアーム４ａ，４ｂに入力される荷重は、弾性部材１８と車両後方側の弾性部材１９との双方から略均等に入力され、弾性部材１８，１９の耐久性を損なう要因となる荷重負担の偏りを改善することができる。むろん、同効果は、弾性部材１９の設置によって、荷重入力中心Ｃ１から弾性部材１９までの距離Ｑが増加して、荷重入力中心Ｃ１から弾性部材１８までの距離Ｐに近づくこと、さらには距離Ｑの増加により、弾性部材１８から弾性部材１９までの点間前後距離（Ｐ＋Ｑ）が増大することにもよる。
【００３９】
しかも、図２に示されるように荷重入力中心Ｃ１から弾性部材１８までの距離Ｐと、荷重入力中心Ｃ１から弾性部材１９までの距離Ｑとを略等しくすると、一層、後輪１０から入力される荷重が、弾性部材１８と弾性部材１９との双方に対して均等に入力されるようになり、より両弾性部材１８，１９の耐久性の向上が図れる。
【００４０】
即ち、トレーリングアーム４ａ，４ｂを介してクロスメンバ１に入力される荷重によりＦ点（弾性部材１８）にかかる荷重をＷｆ、Ｒ点（弾性部材１９）にかかる荷重をＷｒとしたとき、図４に示されるように、上記荷重の中心が弾性部材１８から弾性部材１９に向かうにつれて弾性部材１９に作用する上下方向の荷重Ｗｒは大きくなる一方、弾性部材１８に作用する上下方向の荷重Ｗｆは小さくなる。従って、荷重入力中心Ｃ１から弾性部材１８までの距離Ｐと荷重入力中心Ｃ１から弾性部材１９までの距離Ｑとが等しくなるところ｛（Ｐ＋Ｑ）／２｝で、弾性部材１８に作用する上下方向の荷重Ｗｒと弾性部材１９に作用する上下方向の荷重Ｗｆとが等しくなり、荷重が均等に分配され両弾性部材１８，１９の耐久性を向上させることができる。また、クロスメンバ１に対する入力の偏りを少なくすることができるため、車両の乗り心地も向上させることができる。
【００４１】
なお、下記の与式１を満たすように荷重の入力中心の値を設定すると、前後における極端な上下方向荷重の偏りを回避することができ、実用上十分に両弾性部材１８，１９の耐久性を向上させることができる。
【００４２】
与式１：｛（Ｐ＋Ｑ）／２｝×０．７≦Ｐ≦｛（Ｐ＋Ｑ）／２｝×１．３
特に一実施形態のような後輪１０を支持する支持部をなすハブ部材１１と、コイルスプリング１４の支持部と、トレーリングアーム４ａ，４ｂの車内側のアームピボット９ｂとの三つの部位が直線上に並ぶ（Ｗ／Ｓ点、Ｓ点、Ｇ点が直線α上に並ぶ関係）といった、弾性部材１８，１９の荷重負担が偏りやすくなる（一直線に並ぶ区間でシーソーのような荷重の伝達経路が形成されることによる）サスペンション装置には、コイルスプリング１４の位置と略同じ車両前後方向の位置に弾性部材１９を設ける構造は、弾性部材１８，１９の上下方向入力を平均化させるのには有効である。
【００４３】
また各弾性部材１８，１９のばね定数を同一とせずに（双方のばね定数が同一の場合、弾性中心Ｃ２はＦ，Ｒ点からの距離が等しい地点）、図２に示されるように各弾性部材１８，１９のばね定数の調整で、各弾性部材１８，１９の弾性中心Ｃ２をクロスメンバ１の荷重入力中心Ｃ１に近づけると、クロスメンバ１のピッチングの発生要因となる両中心の差Ｔを小さくすることができる。これにより、荷重入力に対するクロスメンバ１のピッチング量が低減され、車両の操縦安定性の向上を図ることができる。
【００４４】
即ち、車幅方向に２つ配設された弾性部材１８両方の上下方向のばね定数をａ、弾性部材１８よりも車両後方側で車幅方向に２つ配設された弾性部材１９両方の上下方向のばね定数をｂとしたとき、弾性部材１８の上下方向の変位量ＺａはＺａ＝Ｗｆ／ａと表すことができ、弾性部材１９の上下方向の変位量Ｚｂは、Ｚｂ＝Ｗｒ／ｂと表すことができる。また、弾性中心Ｃ２と弾性部材１８との距離をＵとすると、Ｕ＝（Ｐ＋Ｑ）ｂ／（ａ＋ｂ）と表すことができ、荷重入力中心Ｃ１と弾性中心Ｃ２との距離（オフセット）Ｔは、Ｔ＝Ｐ−Ｕと表すことができる。
【００４５】
このとき、図５に示すように、オフセットＴが大きいと現状の荷重入力中心Ｃ１における弾性部材１９の変位量Ｚａと弾性部材１９の変位量Ｚｂとの差Ｈが比較的大きくなる一方、ばね定数ａとばね定数ｂを適宜変更させてオフセットを比較的小さい値Ｔ′とすると、現状の荷重入力中心Ｃ１における弾性部材１９の変位量Ｚａと弾性部材１９の変位量Ｚｂとの差Ｈ′を比較的小さな値とすることができ、ピッチング量を低減することができる。
【００４６】
そして、オフセットＴを０にすると、現状の荷重入力中心Ｃ１において弾性部材１８の変位量Ｚａと弾性部材１９の変位量Ｚｂとが等しくなって、クロスメンバ１のピッチング量を０とすることができ、車両の操縦安定性を最も向上させることができる。
【００４７】
なお、オフセットＴを以下の与式２を満たす値とすれば、実用上クロスメンバ１のピッチング量は十分低減され、車両の操縦安定性の向上を図ることができる。
【００４８】
与式２：−０．１Ｕ≦Ｔ≦０．１｛（Ｐ＋Ｑ）−Ｕ｝
また弾性部材１９の設定に際し、弾性部材１９をトレーリングアーム４ａ，４ｂよりも車内側に配置したので、上下に揺動するトレーリングアーム４ａ，４ｂと弾性部材１９との干渉を回避でき、良好に荷重入力の偏りを改善することができる。
【００４９】
なお、本発明は一実施形態に限定されるものではなく、本発明の主旨を逸脱しない範囲内で種々変更して実施しても構わない。すなわち、一実施形態では、第１弾性部材をクロスメンバより前方に配置する構造を例に挙げたが、クロスメンバと同じ位置、例えばクロスメンバ端に第１弾性部材を配置する構造でも構わない。また例えば一実施形態では、Ｅ形のブラケットを用いて車両後方の弾性部材をコイルスプリングの位置と略同じ位置に配置する構造を挙げたが、これに限らず位、他の部材や構造で、コイルスプリングと略同じ位置に設けるようにしてもよい。また一実施形態では、デファレンシャルが付いたリヤのサスペンション装置に本発明を適用したが、これに限らず、デファレンシャルの無いリヤのサスペンション装置に本発明を適用してもよい。また一実施形態では、後退角をもつセミトレーリングアームを用いたサスペンション装置を挙げたが、これに限らず、後退角の無いフルトレーリングアームを用いたサスペンション装置に本発明を適用してもよい。また、上記実施形態例では、弾性部材１９の弾性中心Ｒをコイルスプリング１４のＳ点と車両前後方向で略同じ一となるように設定したが、少なくとも弾性部材１９の外周面とコイルスプリング１４の外周面とが重複するような位置にあれば、本実施形態例と略同様の作用効果を奏するものである。
【００５０】
【発明の効果】
以上説明したように請求項１、請求項３および請求項６に記載の発明によれば、車輪からサスペンションアームに入力される荷重が、クロスメンバと同じ位置かそれより車両前方側に配置される第１弾性部材とクロスメンバから車両後方側に配置される第２弾性部材との双方から略均等に入力させることが可能となり、両弾性部材の耐久性を損なう要因となる荷重負担の偏りを防ぐことができる。
【００５１】
したがって、クロスメンバを支える両弾性部材における耐久性の向上を図ることができる。特にサスペンションアームにおける車輪側の支持部と、サスペンションアームにおけるスプリングの支持部と、サスペンションアームにおける車内側の端部を支持する支持部が直線上に並ぶという、クロスメンバを支持する弾性部材の荷重負担が偏りやすいサスペンション装置には有効である。
【００５２】
請求項２に記載の発明によれば、一層、車輪から入力される荷重を第１弾性部材と第２弾性部材との双方に均等に入力させることが可能となり、両弾性部材の耐久性をより向上させることができるといった効果を奏する。
【００５３】
請求項４に記載の発明によれば、上下に揺動するサスペンションアームと第２弾性部材との干渉が回避されるので、支障なく良好な荷重負担の偏りの改善ができるといった効果を奏する。
【００５４】
請求項５に記載の発明によれば、第１、第２弾性部材の弾性中心をクロスメンバの荷重入力中心に近づけて、ピッチングの発生の要因となる両中心の差を小さくすることができ、荷重入力時のクロスメンバのピッチング量を抑えて、車両の操縦安定性の向上が図れるといった効果を奏する。
【００５５】
請求項７に記載の発明によれば、さらに前後における極端な上下方向荷重の偏りを回避することができ、実用上十分に第１、第２弾性部材の耐久性を向上させることができるといった効果を奏する。
【００５６】
請求項８に記載の発明によれば、実用上クロスメンバのピッチング量を十分低減でき、車両の操縦安定性の向上を図ることができるといった効果を奏する。
【図面の簡単な説明】
【図１】本発明の一実施形態に係るサスペンション装置の外観を示す斜視図。
【図２】同サスペンション装置の平面図。
【図３】図１中のＡ〜Ａ線に沿う、デファレンシャルを除いたサスペンション装置の背面図。
【図４】第１、第２弾性部材に作用する上下方向の荷重を説明するための線図。
【図５】第１、第２弾性部材の上下方向の変位量を説明するための線図。
【符号の説明】
１…クロスメンバ、４ａ，４ｂ…トレーリングアーム（サスペンションアーム）、９ａ，９ｂ…アームピボット（車外側支持部，車内側支持部）、１０…後輪（車輪）、１１…ハブ部材、１４…コイルスプリング（スプリング）、１７ａ，１７ｂ…弾性支持部材、１８，１９…弾性部材（第１弾性部材，第２弾性部材）、２０…ブラケット。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle suspension apparatus in which a cross member that supports a suspension arm is mounted on a vehicle body side by a plurality of elastic members.
[0002]
[Prior art]
2. Description of the Related Art A suspension device that independently suspends a rear wheel of an automobile (vehicle) has a structure that uses a trailing arm (suspension arm) to suspend the rear wheel (wheel) so as to be swingable up and down.
[0003]
This trailing arm type suspension device normally uses a cross member extending in the width direction of the vehicle body as a frame, and a trailing arm extending rearward of the vehicle is disposed on both sides of the cross member in the vehicle width direction. The end of the arm on the front side of the vehicle is supported on the cross member so as to be swingable in the vertical direction, and the rear wheel is supported on the end of the trailing arm on the rear side of the vehicle so as to be rotatable. A structure in which a spring is interposed is used. That is, in this structure, when the rear wheel receives a load, the trailing arm swings up and down.
[0004]
In such a trailing arm type suspension device, the end of the cross member is elastically supported on the lower surface of the vehicle body in order to suppress the transmission of impact force and vibration to the vehicle body. Recently, in order to reduce load burden and improve riding comfort, each end of the cross member is elastically supported on the vehicle body side using an elastic member arranged in the vehicle front-rear direction. Most of them are elastic support at four points on the left and right sides, providing elastic members near the end of the cross member and on the inner side in the vehicle width direction close to it, and supporting the end of the cross member from both sides in the vehicle longitudinal direction. A structure in which the cross member is mounted on the vehicle body side is employed (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2002-127935 A
[0006]
[Problems to be solved by the invention]
By the way, in the suspension device using the trailing arm, when the respective parts are determined in consideration of the assembly to the vehicle, the trailing arm (wheel) is used for the trailing arm (wheel) from the load input center in the vertical direction of the cross member. The input center of the load in the vertical direction inputted to the cross member is determined near the elastic member on the vehicle rear side among the elastic members that most elastically support the cross member.
[0007]
For this reason, among the elastic members that elastically support the cross member, the load burden on the elastic member on the vehicle rear side is large, and there is a risk that only the durability of the elastic member on the vehicle rear side is undesirably reduced.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle suspension device that can improve the durability of an elastic member that supports a cross member.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a first elastic member that elastically supports the cross member at a position on the vehicle front side of the cross member as an elastic support member that elastically supports the cross member on the vehicle body side. A configuration was adopted in which a spring assembled to the suspension arm and a second elastic member elastically supported at substantially the same position in the longitudinal direction of the vehicle body were combined.
[0010]
With this configuration, the load input from the wheel to the cross member via the suspension arm is input substantially equally to the first and second elastic members.
[0011]
That is, the spring that supports the suspension arm is also a part where a load is input from the vehicle rear side to the vehicle body side.
[0012]
Considering the load input with this spring, the position on the rear side of the vehicle, which is substantially the same as the position where the spring is located, is located on the front side of the vehicle with respect to the cross member across the input center of the vertical load acting on the cross member. It can be seen that the load is easily balanced with respect to the first elastic member to be arranged, and that the point can be reliably moved away from the load input center.
[0013]
In other words, the second elastic member on the vehicle rear side provided at this position is a point that is surely separated from the input center of the vertical load acting on the cross member, and the load is also equal to the first elastic member in the vehicle longitudinal direction. It will be placed at a point that is easy to balance.
[0014]
Therefore, the load input from the wheel to the suspension arm is input substantially equally to both the first elastic member and the second elastic member, which improves the bias of the load burden, which is a factor that impairs durability. Is done.
[0015]
In addition to the above object, the invention according to claim 2 further includes an input center in the vertical direction so that the load in the vertical direction input from the wheel is equally input to both the first elastic member and the second elastic member. The distance from the first elastic member to the first elastic member and the distance from the input center in the vertical direction to the second elastic member are substantially equal.
[0016]
The invention according to claim 3 is that the three portions of the support portion on the wheel side of the suspension arm, the support portion of the spring, and the support portion on which the end portion on the inner side of the vehicle is supported are arranged in a straight line. The elastic support member for elastically supporting the cross member is the same as the end of the cross member or on the front side of the vehicle so that the suspension device is prone to have a significant effect on the suspension device in which the load load of the elastic member supported by the cross member tends to be biased. Adopting a configuration in which a first elastic member that is elastically supported at a position and a second elastic member that is elastically supported at a position in the longitudinal direction of the vehicle body that is substantially the same as a spring that is assembled to a suspension arm is employed, and The second elastic member on the rear side of the vehicle is securely moved away from the load input center of the cross member in consideration of the spring arranged in the middle with the inner support portion. Are arranged at points that are easily balanced equally in the longitudinal direction of the vehicle, and as in the case of claim 1, the load in the vertical direction inputted from the wheel is inputted almost equally to both the first elastic member and the second elastic member. Made possible.
[0017]
In the invention according to claim 4, in addition to the above object, the second elastic member is more vehicle than the suspension arm so as to avoid interference between the second elastic member and the suspension arm when improving the load distribution in the vertical direction. It was set as the structure arrange | positioned inside.
[0018]
According to the fifth aspect of the present invention, in addition to the above object, when a load in the vertical direction is input to the first elastic member and the second elastic member so as to suppress the pitching amount of the cross member with respect to the load input in the vertical direction. The elastic center of each of the elastic members is set in the vicinity of the vehicle inner support portion, and the elastic center of each elastic member is brought closer to the load input center of the cross member, thereby reducing the difference between the front and rear positions of the vehicle that causes the occurrence of pitching. I did it.
[0019]
According to a sixth aspect of the present invention, in order to achieve the above object, as the elastic support member for elastically supporting the cross member on the vehicle body side, the first elastic support member is elastically supported at the same position as the cross member or on the vehicle front side. The distance from the input center of the vertical load input to the cross member from the wheel through the suspension arm to the first elastic member using the elastic member and the second elastic member elastically supported on the rear side of the vehicle body from the cross member The distance from the input center to the second elastic member is substantially equal, and the load input from the wheel is input to both the first elastic member and the second elastic member substantially evenly.
[0020]
According to the seventh aspect of the present invention, the distance in the vehicle front-rear direction from the load input center to the first elastic member is P and the load input center from the load input center so as to avoid extreme vertical load bias in the front-rear direction. 2 When the distance in the vehicle longitudinal direction to the elastic member is Q
{(P + Q) / 2} × 0.7 ≦ P ≦ {(P + Q) / 2} × 1.3
Was able to satisfy.
[0021]
According to the eighth aspect of the present invention, the distance in the vehicle front-rear direction from the load input center to the first elastic member is P and the load input center from the load input center so that the pitching amount of the cross member can be sufficiently reduced. 2 The distance in the vehicle longitudinal direction to the elastic member is Q, the distance in the vehicle longitudinal direction from the elastic center of the first elastic member and the second elastic member to the first elastic member is U, and the vehicle from the load input center to the elastic center When the distance in the front-rear direction is T
−0.1 U ≦ T ≦ 0.1 {(P + Q) −U}
I was able to satisfy.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on an embodiment shown in FIGS.
[0023]
FIG. 1 shows an overall appearance of a trailing arm suspension device employed on the rear side of, for example, a rear wheel drive vehicle (vehicle) or a front wheel drive vehicle (vehicle) to which the present invention is applied, and FIG. 2 shows the suspension. FIG. 3 is a plan view of the apparatus, and FIG. 3 is a rear view of the suspension apparatus as seen from line A to A in FIG.
[0024]
In the figure, reference numeral 1 denotes a cross member forming a frame of the trailing arm type suspension apparatus, and 2 denotes a differential disposed on the central rear side of the cross member 1. Note that the cross member 2 and the differential 2 are both components disposed on the lower side of the vehicle body (not shown).
[0025]
The cross member 1 is formed of, for example, a cylindrical member that extends along the vehicle width direction with the center protruding in a mountain shape on both the vehicle rear side and the vehicle upper side. And the case part of the differential 2 is supported in the central mountain-shaped part 1a, and the input part 2a of the differential 2 faces the front of the vehicle. Reference numeral 3 denotes a bar-shaped bracket for supporting the rear end of the differential 2 toward the vehicle body.
[0026]
In addition, trailing arms 4a and 4b corresponding to suspension arms are assembled symmetrically on both sides of the cross member 1 in the vehicle width direction. The trailing arms 4a and 4b are supported by the cross member 1 with the same structure that is the opposite of each other. Specifically, both the trailing arms 4a and 4b have, for example, a side portion 5a that is inclined in the backward direction in accordance with the shape of the inclined portion 1b of the cross member 1, and an outermost portion in the vehicle width direction on the rear side of the vehicle. The top part 5b is formed from a triangular plate-like member having a side part 5c whose inner side in the vehicle width direction is greatly inclined. A side portion 5a extending forward of the vehicle body on the front end side is supported by an inclined portion 1b inclined in the backward direction so as to be rotatable in the vertical direction while maintaining a backward angle. In the support structure, for example, the same side portion 5a is branched into two parts, ie, an outer side in the vehicle width direction and an inner side in the vehicle width direction. The pivot 9a is supported on the outer side of the inclined portion 1b, in this case, on the end side of the cross member 1a which is the outermost side so as to be rotatable in the vertical direction. Further, the end portion 8b on the inner side of the vehicle is supported by a portion closer to the center of the inclined portion 1b via a support portion on the inner side of the vehicle, for example, an arm pivot 9b (only one side is shown) so as to be rotatable in the vertical direction. That is, the arm pivot 9b on the vehicle inner side is disposed at a position shifted to the vehicle direction side from the arm pivot 9a on the vehicle outer side. The trailing arms 4a and 4b are supported by the arm pivots 9a and 9b arranged along the receding angle so as to be swingable in the vertical direction.
[0027]
A part to which a rear wheel 10 (shown in FIG. 1 only: corresponding to the wheel of the present application) is assembled, for example, a hub member 11 is rotatable on the top 5b side which is the vehicle rear end side of each trailing arm 4a, 4b. Provided, the left and right rear wheels 10 are supported so as to be displaceable in the vertical direction. Thereby, the load of the up-down direction from the rear-wheel 10 is input into the cross member 1 via the trailing arms 4a and 4b. At this time, the input center (hereinafter referred to as load input center) C1 (shown in FIG. 2) of the vertical load inputted to the cross member 1 is a support portion of the cross member 1 due to the support structure of the trailing arms 4a and 4b. , Specifically, on a line passing near the arm pivot 9b disposed inside the vehicle. For example, the rear axle 2b extending from the differential 2 to both sides in the vehicle width direction is connected to each hub member 11 via a pair of universal joints, for example, a constant velocity joint 13 (only one side is shown).
[0028]
In addition, an impact buffering spring, for example, a coil spring 14 is placed vertically in the center of the upper surface of each trailing arm 4a, 4b. The coil springs 14 are supported at a lower end portion by a spring seat 14a (corresponding to a support portion for supporting the spring) formed on the trailing arms 4a and 4b, and an upper end portion is supported by a lower surface side of a vehicle body (not shown). The trailing arms 4a and 4b are elastically supported in the vertical direction. Here, since the coil spring 14 is disposed on the trailing arms 4a and 4b having a limited size, the coil spring seat 14a of the coil spring 14 is structurally arranged as shown in FIG. For example, the W / C point that is the wheel center that is the axis center of the hub member 11 and the G point that is the axis center of the arm pivot 9b inside the vehicle tend to be disposed on the line α. . That is, the trailing arm type suspension device of the present embodiment is configured such that the W / C point of the hub member 11, the S point serving as the axis of the spring coil end on the trailing arm side, The point G of the arm pivot 9b is arranged on a substantially straight line.
[0029]
A shock absorber 15 supported by a vehicle body (not shown) is connected to the top 5b side of each trailing arm 4a, 4b, so that shock and vibration from the rear wheel 10 transmitted through the trailing arms 4a, 4b are attenuated. The structure is made. Reference numeral 16 denotes a stabilizer (for example, an intermediate portion is supported by the cross member 1 and end portions are formed of U-shaped bar members connected to the trailing arms 4a and 4b, respectively).
[0030]
A pair of elastic support members 17a and 17b for elastically supporting the cross member 1 on the vehicle body side are provided on the left and right sides (vehicle width direction) of the cross member 1. The elastic support members 17a and 17b have a pair of left and right elastic members that are assembled at the same position as the cross member 1 or at the front side of the vehicle. A structure in which a pair of elastic members 18 and a pair of left and right elastic members 19 provided at the central portion of the cross member 1 so as to protrude toward the rear of the vehicle is used.
[0031]
Specifically, the elastic member 18 is an elastically displaceable cylindrical bush that can be supported on the vehicle body side by bolting, for example, an elastic bush formed of a rubber material or the like. For example, the bracket 12a that supports the arm pivot 9a on the outside of the vehicle is formed with a bracket portion 12b on the vehicle body support side that protrudes partly forward of the vehicle, and the elastic member is formed at the tip of the bracket portion 12b. 18 is assembled in the vertical direction (direction in which the axis is arranged in the vertical direction). The remaining elastic member 19 is a cylindrical elastic bush formed of, for example, a rubber material that can be supported on the vehicle body side by, for example, bolting, similarly to the elastic member 18. Further, an E-shaped bracket 20 is attached to the center of the mountain shape of the cross member 1 so as to cover the upper side of the differential 2 in an E shape so as to cover the upper side of the differential 2. The elastic member 19 is assembled in the vertical direction (direction in which the axis is arranged in the vertical direction) symmetrically with the left and right corner portions on the front end side. The assembly positions of these elastic members 19 are substantially the same as the attachment positions of the coil springs 14 on the trailing arms 4a and 4b. Specifically, as shown in FIG. 2, the elastic member 19 is assembled at a point of the bracket 20 where the elastic center R of the elastic member 19 is substantially the same position as the S point of the coil spring 14. By this assembly, the elastic member 19 is disposed at substantially the same position as the coil spring 14 in the longitudinal direction of the vehicle body.
[0032]
Such an elastic member 18 from the cross member 1 to the front of the vehicle and an elastic member 19 from the cross member 1 to the rear of the vehicle are configured to equalize the input load to the elastic members 18 and 19. In addition to the same structure, as shown in FIG. 2, the distance P from the load input center C1 of the cross member 1 to the elastic member 18 and the distance Q from the load input center C1 to the elastic member 19 are made as equal as possible. Each part of the suspension device is adjusted. That is, by this adjustment, the distances P and Q are made substantially equal. Further, as shown in FIGS. 2 and 3, the elastic member 19 is arranged at a point on the vehicle inner side than the trailing arms 4 a and 4 b and has a structure that avoids interference with the swinging trailing arms 4 a and 4 b. There is.
[0033]
As shown in FIG. 2, the elastic center C <b> 2 in the vertical direction of the elastic bush set between the elastic members 18 and 19 is adjusted by adjusting the spring constant of the elastic member 18 and adjusting the spring constant of the elastic member 19. The distance T from the load input center C1 is reduced as much as possible. By this adjustment, the elastic center C2 is set in the vicinity of the load input center C1.
[0034]
In the trailing arm type suspension device configured as described above, when the left and right rear wheels 10 receive a vertical load, the trailing arms 4a and 4b swing up and down around the arm pivots 9a and 9b, A load from the rear wheel 10 is input to the cross member 1. Then, the swinging of the trailing arms 4 a and 4 b is suppressed by the ring arm coil spring 14 and the shock absorber 15.
[0035]
At this time, the load in the vertical direction input from the rear wheel 10 is input to the cross member 1 through both arm pivots 9a and 9b that support the trailing arms 4a and 4b, and is applied to the trailing arms 4a and 4b. It is transmitted to the vehicle body side through a coil spring 14 that supports the middle like a seesaw.
[0036]
At this time, the position on the vehicle rear side substantially the same as the position where the coil spring 14 is installed is the same as the cross member 1 or on the vehicle front side with respect to the load input center C1 of the cross member 1. It can be seen that the load is easily balanced with respect to the elastic member 18 (the elastic member 18 on the vehicle front side away from the load input center C1), and the point is away from the load input center C1. That is, the substantially same position as the coil spring 14 is a suitable position for dispersing the load applied to the trailing arms 4a and 4b.
[0037]
Here, since the elastic member 19 is provided at this position, the loads from the trailing arms 4a and 4b are input to the elastic member 19 without being concentrated.
[0038]
Therefore, the load input from the rear wheel 10 to the trailing arms 4a and 4b is input substantially equally from both the elastic member 18 and the elastic member 19 on the rear side of the vehicle, thereby improving the durability of the elastic members 18 and 19. It is possible to improve the imbalance of the load burden that causes damage. Of course, the effect is that the distance Q from the load input center C1 to the elastic member 19 is increased by the installation of the elastic member 19 and approaches the distance P from the load input center C1 to the elastic member 18, and further the distance Q This is also due to the increase in the distance between the front and back points (P + Q) from the elastic member 18 to the elastic member 19 due to the increase in.
[0039]
Moreover, if the distance P from the load input center C1 to the elastic member 18 and the distance Q from the load input center C1 to the elastic member 19 are substantially equal as shown in FIG. The load is uniformly input to both the elastic member 18 and the elastic member 19, and the durability of both the elastic members 18 and 19 can be further improved.
[0040]
That is, when the load applied to the point F (elastic member 18) by the load input to the cross member 1 via the trailing arms 4a and 4b is Wf, and the load applied to the point R (elastic member 19) is Wr. 4, the vertical load Wr acting on the elastic member 19 increases as the center of the load moves from the elastic member 18 toward the elastic member 19, while the vertical load Wf acting on the elastic member 18 is Get smaller. Therefore, the distance P from the load input center C1 to the elastic member 18 and the distance Q from the load input center C1 to the elastic member 19 are equal to {(P + Q) / 2} in the vertical direction acting on the elastic member 18. The load Wr and the vertical load Wf acting on the elastic member 19 are equal, and the load is evenly distributed, so that the durability of the elastic members 18 and 19 can be improved. Moreover, since the bias of the input to the cross member 1 can be reduced, the riding comfort of the vehicle can be improved.
[0041]
Note that if the value of the load input center is set so as to satisfy the following formula 1, extreme vertical load bias in the front and rear can be avoided, and the durability of the two elastic members 18 and 19 is sufficiently practical. Can be improved.
[0042]
Formula 1: {(P + Q) / 2} × 0.7 ≦ P ≦ {(P + Q) / 2} × 1.3
In particular, the three parts of the hub member 11 that forms a support part for supporting the rear wheel 10, the support part of the coil spring 14, and the arm pivot 9 b inside the trailing arms 4 a and 4 b as shown in FIG. The load load on the elastic members 18 and 19 is easily biased such that the W / S point, the S point, and the G point are aligned on the straight line α (load transmission path like a seesaw in a straight line section). In the suspension device, the structure in which the elastic member 19 is provided at a position in the vehicle front-rear direction substantially the same as the position of the coil spring 14 is used to average the vertical input of the elastic members 18 and 19. It is valid.
[0043]
Further, without making the spring constants of the elastic members 18 and 19 the same (when both spring constants are the same, the elastic center C2 is a point where the distances from the points F and R are equal), as shown in FIG. If the elastic center C2 of each elastic member 18, 19 is brought close to the load input center C1 of the cross member 1 by adjusting the spring constants of the members 18, 19, the difference T between the two centers that causes the cross member 1 to pitch is obtained. Can be small. Thereby, the pitching amount of the cross member 1 with respect to the load input is reduced, and the steering stability of the vehicle can be improved.
[0044]
That is, the vertical spring constants of both the elastic members 18 arranged in the vehicle width direction are a, and the upper and lower elastic constants of the two elastic members 19 arranged in the vehicle width direction on the vehicle rear side from the elastic member 18. When the direction spring constant is b, the vertical displacement amount Za of the elastic member 18 can be expressed as Za = Wf / a, and the vertical displacement amount Zb of the elastic member 19 is Zb = Wr / b. Can be represented. Further, if the distance between the elastic center C2 and the elastic member 18 is U, it can be expressed as U = (P + Q) b / (a + b), and the distance (offset) T between the load input center C1 and the elastic center C2 is: T = P−U.
[0045]
At this time, as shown in FIG. 5, if the offset T is large, the difference H between the displacement amount Za of the elastic member 19 and the displacement amount Zb of the elastic member 19 at the current load input center C1 becomes relatively large, while the spring constant is increased. If the offset is set to a relatively small value T ′ by appropriately changing a and the spring constant b, the difference H ′ between the displacement amount Za of the elastic member 19 and the displacement amount Zb of the elastic member 19 at the current load input center C1 is compared. Therefore, the pitching amount can be reduced.
[0046]
When the offset T is set to 0, the displacement amount Za of the elastic member 18 and the displacement amount Zb of the elastic member 19 become equal at the current load input center C1, and the pitching amount of the cross member 1 can be reduced to 0. The vehicle handling stability can be most improved.
[0047]
If the offset T is set to a value that satisfies the following Expression 2, the pitching amount of the cross member 1 can be practically reduced sufficiently, and the steering stability of the vehicle can be improved.
[0048]
Formula 2: −0.1 U ≦ T ≦ 0.1 {(P + Q) −U}
In setting the elastic member 19, the elastic member 19 is disposed on the vehicle inner side than the trailing arms 4a and 4b, so that interference between the trailing arms 4a and 4b swinging up and down and the elastic member 19 can be avoided. The load input bias can be improved.
[0049]
The present invention is not limited to one embodiment, and various modifications may be made without departing from the spirit of the present invention. That is, in one embodiment, the structure in which the first elastic member is disposed in front of the cross member is described as an example. However, the first elastic member may be disposed at the same position as the cross member, for example, at the end of the cross member. Further, for example, in one embodiment, the structure in which the elastic member at the rear of the vehicle is arranged at substantially the same position as the position of the coil spring using the E-shaped bracket is not limited to this, but with other members and structures, You may make it provide in the substantially same position as a coil spring. In one embodiment, the present invention is applied to a rear suspension apparatus with a differential. However, the present invention is not limited to this, and the present invention may be applied to a rear suspension apparatus without a differential. In one embodiment, a suspension device using a semi-trailing arm having a receding angle has been described. However, the present invention is not limited thereto, and the present invention may be applied to a suspension device using a full trailing arm having no receding angle. Good. In the above embodiment, the elastic center R of the elastic member 19 is set to be substantially the same as the point S of the coil spring 14 in the vehicle front-rear direction, but at least the outer peripheral surface of the elastic member 19 and the coil spring 14 If it is at a position where the outer peripheral surface overlaps, the same effects as the present embodiment can be achieved.
[0050]
【The invention's effect】
As described above, according to the first, third, and sixth aspects of the invention, the load input from the wheel to the suspension arm is arranged at the same position as the cross member or at the front side of the vehicle. Input from both the first elastic member and the second elastic member arranged on the rear side of the vehicle from the cross member can be made to be substantially even, thereby preventing an uneven load burden that impairs the durability of both elastic members. be able to.
[0051]
Therefore, it is possible to improve the durability of both elastic members that support the cross member. In particular, the load on the elastic member supporting the cross member is such that the wheel side support part of the suspension arm, the spring support part of the suspension arm, and the support part of the suspension arm that supports the end of the vehicle inside are arranged in a straight line. This is effective for suspension devices that tend to bias.
[0052]
According to the second aspect of the present invention, it is possible to uniformly input the load input from the wheel to both the first elastic member and the second elastic member, and the durability of both elastic members can be further increased. There is an effect that it can be improved.
[0053]
According to the fourth aspect of the present invention, since the interference between the suspension arm swinging up and down and the second elastic member is avoided, there is an effect that it is possible to improve the bias of a good load burden without any trouble.
[0054]
According to the fifth aspect of the present invention, the elastic center of the first and second elastic members can be brought close to the load input center of the cross member, and the difference between the two centers that causes the occurrence of pitching can be reduced. There is an effect that the steering stability of the vehicle can be improved by suppressing the pitching amount of the cross member at the time of load input.
[0055]
According to the invention described in claim 7, it is possible to further avoid extreme vertical load biases in the front and rear, and to effectively improve the durability of the first and second elastic members. Play.
[0056]
According to the eighth aspect of the invention, there is an effect that the amount of pitching of the cross member can be practically reduced and the steering stability of the vehicle can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of a suspension device according to an embodiment of the present invention.
FIG. 2 is a plan view of the suspension device.
FIG. 3 is a rear view of the suspension device, excluding a differential, taken along line AA in FIG. 1;
FIG. 4 is a diagram for explaining a vertical load acting on the first and second elastic members.
FIG. 5 is a diagram for explaining the amount of vertical displacement of the first and second elastic members.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Cross member, 4a, 4b ... Trailing arm (suspension arm), 9a, 9b ... Arm pivot (vehicle outside support part, vehicle inside support part), 10 ... Rear wheel (wheel), 11 ... Hub member, 14 ... Coil springs (springs), 17a, 17b ... elastic support members, 18, 19 ... elastic members (first elastic member, second elastic member), 20 ... brackets.

Claims

A cross member extending in the vehicle width direction;
One end side is supported on the wheel side, and the other end side extends forward of the vehicle body and is supported by the cross member;
A spring whose lower end is supported by the suspension arm and whose upper end is supported by the vehicle body;
An elastic support member that elastically supports the cross member on the vehicle body side;
In a vehicle suspension apparatus in which an input center of a vertical load input from the wheel to the cross member through the suspension arm is positioned in the vicinity of the support member on the cross member side of the suspension arm.
The elastic support member is
A first elastic member provided on the vehicle front side of the cross member;
A vehicle suspension apparatus comprising: a second elastic member disposed at substantially the same position as the spring in the longitudinal direction of the vehicle body.

2. The vehicle suspension device according to claim 1, wherein a distance from the input center to the first elastic member is substantially equal to a distance from the input center to the second elastic member.

A cross member extending in the vehicle width direction;
One end side is supported on the wheel side, the other end side extends forward of the vehicle body, the end portion is branched to the vehicle width direction outer side and the vehicle width direction inner side, and the vehicle outer end portion is the vehicle outer side support portion. A suspension arm that is supported by the cross member at a vehicle inner side support portion that is disposed on the vehicle rear side with respect to the vehicle outer side support portion.
A spring whose lower end is supported by the suspension arm and whose upper end is supported by the vehicle body;
An elastic support member that elastically supports the cross member on the vehicle body side;
In the suspension device for a vehicle, the support portion for the wheel side of the suspension arm, the support portion for the suspension arm of the spring, and the vehicle interior support portion are arranged in a substantially straight line.
The elastic support member is the same as the end of the cross member or a first elastic member disposed on the vehicle front side from the end,
A vehicle suspension apparatus comprising: a second elastic member disposed at substantially the same position as the spring in the longitudinal direction of the vehicle body.

4. The vehicle suspension device according to claim 1, wherein the second elastic member is disposed on an inner side of the vehicle than the suspension arm. 5.

The elastic center when a load in the vertical direction is input to the first elastic member and the second elastic member is set in the vicinity of the vehicle interior support portion. The vehicle suspension apparatus described.

A cross member extending in the vehicle width direction;
One end side is supported on the wheel side, and the other end side extends forward of the vehicle body and is supported by the cross member;
A spring whose lower end is supported by the suspension arm and whose upper end is supported by the vehicle body;
In a vehicle suspension apparatus having an elastic support member that elastically supports the cross member on the vehicle body side,
The elastic support member includes a first elastic member provided on the vehicle front side of the cross member, and a second elastic member provided on the vehicle body rear side of the cross member,
The distance from the input center of the vertical load input to the cross member through the suspension arm from the wheel to the first elastic member is made substantially equal to the distance from the input center to the second elastic member. A suspension system for a vehicle.

A cross member extending in the vehicle width direction;
One end side is supported on the wheel side, and the other end side extends forward of the vehicle body and is supported by the cross member;
A spring whose lower end is supported by the suspension arm and whose upper end is supported by the vehicle body;
In a vehicle suspension apparatus having an elastic support member that elastically supports the cross member on the vehicle body side,
The elastic support member includes a first elastic member provided on the vehicle front side with respect to a load input center input to the cross member from the wheel via the suspension arm, and a vehicle rear side with respect to the load input center. A second elastic member provided on the side,
The distance in the vehicle longitudinal direction from the load input center to the first elastic member is P,
When the distance in the vehicle longitudinal direction from the load input center to the second elastic member is Q, the following expression {(P + Q) / 2} × 0.7 ≦ P ≦ {(P + Q) / 2} × 1.3
A vehicle suspension device characterized by satisfying the above.

A cross member extending in the vehicle width direction;
One end side is supported on the wheel side, and the other end side extends forward of the vehicle body and is supported by the cross member;
A spring whose lower end is supported by the suspension arm and whose upper end is supported by the vehicle body;
In a vehicle suspension apparatus having an elastic support member that elastically supports the cross member on the vehicle body side,
The elastic support member includes a first elastic member provided on the vehicle front side with respect to a load input center input to the cross member from the wheel via the suspension arm, and a vehicle rear side with respect to the load input center. A second elastic member provided on the side,
The distance in the vehicle longitudinal direction from the load input center to the first elastic member is P,
The distance in the vehicle longitudinal direction from the load input center to the second elastic member is Q,
The distance in the vehicle front-rear direction from the elastic center of the first elastic member and the second elastic member to the first elastic member is U,
When the distance in the vehicle longitudinal direction from the load input center to the elastic center is T, the following equation −0.1 U ≦ T ≦ 0.1 {(P + Q) −U}
A vehicle suspension device characterized by satisfying the above.