JP3932025B2

JP3932025B2 - Anti-vibration bush

Info

Publication number: JP3932025B2
Application number: JP2002072063A
Authority: JP
Inventors: 勝久池田
Original assignee: Sumitomo Riko Co Ltd
Current assignee: Sumitomo Riko Co Ltd
Priority date: 2002-03-15
Filing date: 2002-03-15
Publication date: 2007-06-20
Anticipated expiration: 2022-03-15
Also published as: JP2003269509A

Description

【０００１】
【技術分野】
本発明は、径方向で互いに離隔配置されたインナ軸部材とアウタ筒部材を本体ゴム弾性体で連結せしめた構造の防振ブッシュに係り、例えば自動車用のサスペンションブッシュやサブフレームマウント，ボデーマウント等として採用され得る防振ブッシュに関するものである。
【０００２】
【背景技術】
従来から、振動伝達系を構成する部材間に介装される防振装置の一種として、例えば特開平１１−２２８９号公報や特開平９−２８０３１４号公報等に記載されているように、インナ軸部材の径方向外方にアウタ筒部材を離隔配置すると共に、それらインナ軸部材とアウタ筒部材の径方向対向面間に本体ゴム弾性体を配設してインナ軸部材とアウタ筒部材に本体ゴム弾性体を加硫接着することにより、インナ軸部材とアウタ筒部材を弾性連結せしめた構造の防振ブッシュが、知られている。
【０００３】
また、このような防振ブッシュでは、インナ軸部材とアウタ筒部材の間に径方向の大きな荷重が及ぼされた際に本体ゴム弾性体の弾性変形量を制限するストッパ機構が採用されることが多く、かかるストッパ機構の一つとして、前記公報にも記載されているように、アウタ筒部材に環状ストッパを嵌着固定せしめて、該環状ストッパの内周面をインナ軸部材に対して径方向で所定距離を隔てて対向位置させた構造のものが提案されている。かくの如きストッパ機構では、アウタ筒部材の内周面に保持ゴム層を形成して該保持ゴム層の内周面に環状ストッパを内挿配置せしめた後に、アウタ筒部材を絞り加工等で縮径することにより、環状ストッパが保持ゴム層を介してアウタ筒部材に嵌着固定されている。即ち、保持ゴム層を介在させることにより、アウタ筒部材の縮径量のバラツキや環状ストッパの寸法誤差等を吸収させて、環状ストッパの損傷を回避しつつ環状ストッパをアウタ筒部材に対して安定して嵌着固定することが出来るようになっているのである。
【０００４】
ところで、環状ストッパをアウタ筒部材に嵌着固定するに際しては、環状ストッパのインナ軸部材側への当接によって目的とするストッパ機能を安定して得ると共に、環状ストッパの他部材への緩衝等を回避するために、アウタ筒部材において予め設定された所定位置に環状ストッパを精度良く固定することが要求される。
【０００５】
しかしながら、前記公報に記載されている如き従来構造の防振ブッシュにおいては、アウタ筒部材に対する環状ストッパの位置決めが何等考慮されておらず、アウタ筒部材に環状ストッパを挿し入れるに際して環状ストッパを正確に位置決めすることが難しいという問題があった。
【０００６】
しかも、アウタ筒部材に差しいれた後の環状ストッパの所定位置への保持も何等考慮されていないために、たとえ環状ストッパをアウタ筒部材に対して正確な位置に挿し入れたとしても、その後のアウタ筒部材への縮径加工に際しての搬送や八方絞り等の作業に際して環状ストッパがアウタ筒部材に対して位置ずれし易いという問題もあった。
【０００７】
特に、本体ゴム弾性体の耐久性向上やばね特性改善等のためにアウタ筒部材に対する縮径量が大きく設定される場合には、アウタ筒部材の縮径に際しての環状ストッパの損傷を回避するために、アウタ筒部材とそこに挿し入れられる環状ストッパの径方向間に隙間が設定される場合もあり、そのような隙間が形成されると環状ストッパをアウタ筒部材に挿し入れる際の位置合わせや、挿し入れた後の位置決めが一層難しくなる。また、前記特開平１１−２２８９号公報に記載されているようにアウタ筒部材の軸方向両端部にそれぞれ環状ストッパを組み付ける場合には、環状ストッパをアウタ筒部材に差し入れた後、アウタ筒部材を何れの軸方向に傾斜させても何れかの環状ストッパが抜け出して脱落するおそれがあることから、アウタ筒部材の軸方向一端部だけに環状ストッパを組み付ける場合よりも、環状ストッパを目的とする位置に正確に嵌着固定することが一層難しくなる。
【０００８】
なお、アウタ筒部材に環状ストッパを挿し入れる際の環状ストッパの位置合わせを正確にするために、例えば保持ゴム層に段差面を形成し、環状ストッパの挿し入れ側の軸方向端面を該段差面に当接させることによって環状ストッパのアウタ筒部材への挿し入れ端を規定することも考えられる。ところが、このような段差面は環状ストッパを挿し入れた際に外部から見えなくなることから、環状ストッパが段差面に当接した状態にあるか否かを確認する作業自体が面倒で難しいという問題があり、未だ有効な解決策となり得るものではないのである。
【０００９】
【解決課題】
ここにおいて、本発明は上述の如き事情を背景として為されたものであって、その解決課題とするところは、径方向のストッパ機構を構成する環状ストッパ部材をアウタ筒部材に対して容易に且つ良好な位置精度をもって嵌着固定することの出来る、新規な構造の防振ブッシュを提供することにある。
【００１０】
【解決手段】
以下、このような課題を解決するために為された本発明の態様を記載する。なお、以下に記載の各態様において採用される構成要素は、可能な限り任意の組み合わせで採用可能である。また、本発明の態様乃至は技術的特徴は、以下に記載のものに限定されることなく、明細書全体および図面に記載され、或いはそれらの記載から当業者が把握することの出来る発明思想に基づいて認識されるものであることが理解されるべきである。
【００１１】
すなわち、本発明の第一の態様の特徴とするところは、インナ軸部材の径方向外方にアウタ筒部材が離隔配置されると共に、それらインナ軸部材とアウタ筒部材の径方向対向面間に本体ゴム弾性体が配設されて該本体ゴム弾性体が該インナ軸部材の外周面と該アウタ筒部材の内周面にそれぞれ加硫接着せしめられた防振ブッシュにおいて、前記インナ軸部材および前記アウタ筒部材における軸方向の少なくとも一方の端部に前記本体ゴム弾性体による連結部位から軸方向に延び出して互いに径方向で対向位置する軸方向延出部がそれぞれ形成されて、該アウタ筒部材の該軸方向延出部の内周面に広がる保持ゴム層が該本体ゴム弾性体と一体形成されており、該保持ゴム層において径方向内方に開口して周方向に延びる嵌合凹溝が形成されていると共に、該嵌合凹溝に環状ストッパ部材が挿し入れられて配置せしめられ、該環状ストッパ部材が該嵌合凹溝の軸方向両側壁部で位置決め保持されており、該環状ストッパ部材を保持した該アウタ筒部材が縮径変形されて該環状ストッパ部材が該アウタ筒部材に対して嵌着固定されている防振ブッシュにある。
【００１２】
このような本発明に従う構造とされた防振ブッシュにおいては、環状ストッパ部材が組み付けられるアウタ筒部材の内周面に位置して、周方向に延びる嵌合凹溝が保持ゴム層によって形成されており、環状ストッパ部材が該嵌合凹溝に挿し入れられると共に、環状ストッパ部材の軸方向両端面が嵌合凹溝の軸方向両側壁部で支えられるように保持されることとなる。それ故、環状ストッパ部材を嵌合凹溝に挿し入れるだけで、アウタ筒部材において予め設定された目的とする位置に環状ストッパ部材を正確に位置決めし、且つ軸方向への位置ずれを防止して保持せしめることが出来るのである。しかも、嵌合凹溝は保持ゴム層で形成されていることから、該嵌合凹溝の軸方向外側壁部の弾性変形により、環状ストッパ部材を嵌合凹溝に対して容易に且つ速やかに挿し入れて組み付けることが可能であり、製作も容易となる。
【００１３】
また、環状ストッパ部材を嵌合凹溝に対して正しく挿し入れた状態下では、嵌合凹溝の軸方向外側壁部が環状ストッパ部材の軸方向外面に沿って立ち上がるようにされることから、環状ストッパ部材の組み付けに際して環状ストッパ部材が嵌合凹溝に対して正しく挿し入れられているか否かを外方から容易に視認等で判断することが出来るのであり、それによって、環状ストッパ部材の正しい位置への組み付けを一層確実に行なうことが出来るのである。
【００１４】
なお、本態様において、嵌合凹溝における軸方向一方または両方の側壁部は、周方向で分断された形態をもって形成されていても良いが、好ましくは周方向の全周に亘って連続して形成される。また、嵌合凹溝における軸方向両側壁部は、互いに径方向の立ち上がり高さが同一とされている必要はなく任意であり、例えば嵌合凹溝の軸方向外方の側壁部よりも軸方向内方の側壁部を径方向内方まで立ち上げることにより、環状ストッパ部材の嵌合凹溝への挿し入れを容易とすることが出来ると共に、環状ストッパ部材の軸方向内方への挿し入れ端位置が一層有利に規定され得る。
【００１５】
また、本態様に係る防振ブッシュは、少なくとも最終的な装着状態下においてアウタ筒部材が縮径されることにより環状ストッパ部材が保持ゴム層を介してアウタ筒部材に嵌着固定されることとなるが、アウタ筒部材が縮径される前の状態では、環状ストッパ部材は嵌合凹溝に挿し入れられることでアウタ筒部材に対して位置決め保持されていれば良く、例えば環状ストッパ部材の外周面と嵌合凹溝の底面の間に径方向で多少のガタツキや隙間があっても良い。
【００１６】
更にまた、本態様に係る防振ブッシュは、防振ブッシュ単体の製造工程において、嵌合凹溝に環状ストッパ部材を挿し入れた後にアウタ筒部材に八方絞り等の縮径加工を施すことにより、環状ストッパ部材の外周面を保持ゴム層を介してアウタ筒部材に圧接させて、環状ストッパ部材をアウタ筒部材に固定するようにしても良いが、その他、例えば嵌合凹溝に環状ストッパ部材を挿し入れた後、アウタ筒部材の縮径による環状ストッパ部材のアウタ筒部材への固定前或いは固定未了の状態で防振ブッシュを単体製品として供給し、該防振ブッシュで防振連結される一方の部材に形成されたアームアイ等の防振ブッシュの装着用孔に対して防振ブッシュのアウタ筒部材を圧入固定して装着せしめる際に該アウタ筒部材が縮径されるようにして、装着用孔への防振ブッシュの組付完了に伴って環状ストッパ部材がアウタ筒部材に嵌着固定されるようにしても良い。なお、特にアウタ筒部材の装着用孔への圧入によってアウタ筒部材を縮径させて環状ストッパ部材をアウタ筒部材に嵌着固定する場合には、アウタ筒部材として、鉄鋼等の金属製の他、合成樹脂製のもの等も有利に採用され得る。
【００１７】
また、本態様に係る防振ブッシュにおいて、環状ストッパ部材は、少なくとも本体ゴム弾性体より硬質の合成樹脂や金属等で形成されたものが採用されることとなり、本体ゴム弾性体におけるインナ軸部材とアウタ筒部材の連結部分に対する干渉が回避されるように、かかる連結部分から軸方向に離隔して配設されることが望ましい。更にまた、本体ゴム弾性体におけるインナ軸部材とアウタ筒部材の連結部分を挟んだ軸方向両側に位置するようにして一対の環状ストッパ部材をアウタ筒部材の軸方向両端部に組み付けることが望ましく、それによって、環状ストッパ部材がインナ軸部材側に当接せしめられた際のインナ軸部材とアウタ筒部材に対するこじり方向荷重の作用が軽減乃至は回避され得る。なお、環状ストッパ部材の内周面が当接せしめられるインナ軸部材の外周面には、緩衝ゴム層を形成することが望ましく、好適にはかかる緩衝ゴム層が本体ゴム弾性体と一体形成されるが、その他、環状ストッパ部材の内周面に対して緩衝ゴム層を被着形成しても良い。
【００１８】
また、本発明の第二の態様は、前記第一の態様に係る防振ブッシュにおいて、前記嵌合凹溝の底面に弾性突部を形成して、該弾性突部に対して前記環状ストッパ部材の外周面を部分的に当接せしめたことを、特徴とする。このような本態様に従う構造とされた防振ブッシュにおいては、例えば、アウタ筒部材の縮径量を大きくして本体ゴム弾性体に有効な予圧縮を加える必要があるために、嵌合凹溝の底面とそこに挿し入れられた環状ストッパ部材の径方向間に大きな隙間を形成するに際しても、嵌合凹溝に挿し入れた環状ストッパ部材を弾性突部で安定して保持せしめて、環状ストッパ部材の嵌合凹溝からの抜け出しを効果的に抑えることが可能となる。
【００１９】
なお、本態様において、弾性突部は、環状ストッパ部材の外周面に対して部分的に当接されることにより、環状ストッパ部材に対して有効な径方向の位置決め保持力を及ぼすものであれば良く、例えば、嵌合凹溝の底面に形成した複数の突起や、嵌合凹溝の底面に形成した周方向に延びる周方向突条などで有利に構成され得る。特に周方向の所定長さで或いは全周に亘って連続して延びる弾性突部を採用すれば、環状ストッパ部材に対してより有効な径方向の位置決め保持力を作用せしめることが可能となる。
【００２０】
また、本発明の第三の態様は、前記第一又は第二の態様に係る防振ブッシュにおいて、前記保持ゴム層によって形成された前記嵌合凹溝の軸方向外側の壁部における内周面が、軸方向外方に向かって拡開するテーパ面とされていることを、特徴とする。このような本態様に従う構造とされた防振ブッシュにおいては、環状ストッパ部材を嵌合凹溝に挿し入れるに際して、環状ストッパ部材を嵌合凹溝の軸方向外側の壁部を乗り越えるようにして嵌合凹溝を導き入れることが一層容易となり、目的とする防振ブッシュを一層容易且つ効率的に行なうことが可能となる。
【００２１】
また、本発明の第四の態様は、前記第一乃至第三の何れかの態様に係る防振ブッシュにおいて、前記アウタ筒部材を金属製のアウタ筒金具で構成せしめて、該アウタ筒金具を縮径することによって前記環状ストッパ部材を該アウタ筒金具に対して嵌着固定せしめたことを、特徴とする。このような本態様に従う防振ブッシュにおいては、アウタ筒金具ひいては本体ゴム弾性体の予圧縮を十分に大きく設定することが出来るのであり、それ故、例えば本体ゴム弾性体に対して径方向寸法の３％以上、特に有利には５％以上、更には１０％以上の縮径量をもってアウタ筒金具を縮径加工することも容易に実現可能となる。なお、アウタ筒金具に対する縮径加工は、防振ブッシュを防振すべき振動部材に装着する前に、防振ブッシュ単体の状態で八方絞り等によって有利に実施され得る。
【００２２】
また、本発明の第五の態様は、前記第一乃至第四の何れかの態様に係る防振ブッシュであって、前記環状ストッパ部材において、前記アウタ筒部材側から前記インナ軸部材側に向かって突出する径方向の突出高さを周方向で異ならせたことを、特徴とする。このような本態様に従う構造とされた防振ブッシュにおいては、インナ軸部材とアウタ筒部材の径方向の相対変位量の制限機能を、複数の径方向で異なる特性をもって付与することが出来るのであり、例えばインナ軸部材とアウタ筒部材が初期状態で径方向に偏倚して配設される場合等にも有利に対応することが可能となる。
【００２３】
【発明の実施形態】
以下、本発明を更に具体的に明らかにするために、本発明の実施形態について、図面を参照しつつ、詳細に説明する。
【００２４】
先ず、図１〜２には、本発明の第一の実施形態である防振ブッシュとしての自動車用サスペンションブッシュ１０が、示されている。このサスペンションブッシュ１０は、インナ軸部材としての内筒金具１２とアウタ筒部材としての外筒金具１４が本体ゴム弾性体１６で弾性連結されることによって形成されている。そして、かかるサスペンションブッシュ１０は、例えば図１中に仮想線で示されているように、自動車のサスペンションアーム１８に対して内筒金具１２が固定される一方、自動車のサスペンションメンバ２０に対して外筒金具１４が固定されることにより、サスペンションアーム１８をサスペンションメンバ２０に対して防振連結するようになっている。なお、以下の説明中、軸方向および径方向とは、原則として内筒金具１２または外筒金具１４の軸方向および径方向を言う。
【００２５】
より詳細には、内筒金具１２は、ストレートな円筒形状を有しており、鉄鋼等の金属材で形成されている。一方、外筒金具１４は、内筒金具１２よりも所定量だけ大径のストレートな円筒形状を有しており、内筒金具１２と同様に適当な金属材で形成されている。そして、外筒金具１４が内筒金具１２に外挿されており、外筒金具１４が内筒金具１２の径方向外方に所定距離だけ離隔して略同一中心軸上に配設されている。なお、内筒金具１２は、外筒金具１４よりも軸方向長さが大きくされており、内筒金具１２の軸方向端部が外筒金具１４から軸方向外方に突出せしめられている。
【００２６】
また、これら内筒金具１２と外筒金具１４の径方向対向面間には、本体ゴム弾性体１６が配設されている。この本体ゴム弾性体１６は、略円環ブロック形状を有しており、内外筒金具１２，１４における軸方向の略中央に位置せしめられて、それら内外筒金具１２，１４の径方向対向面間に跨がって配設されている。また、本体ゴム弾性体１６の内外周面は、内筒金具１２の外周面と外筒金具１４の内周面に対してそれぞれ加硫接着されており、それによって、内外筒金具１２，１４が、軸方向の略中央部分で本体ゴム弾性体１６によって弾性連結されている。なお、このことから明らかなように、本実施形態では、本体ゴム弾性体１６が、図３に示されている如く、内外筒金具１２，１４を備えた一体加硫成形品２２として形成されている。また、内筒金具１２の軸方向両側部分および外筒金具１４の軸方向両側部分は、それぞれ、本体ゴム弾性体１６による連結部位である軸方向の略中央部分２４および２６から軸方向外方に延び出した軸方向延出部２８，２８および３０，３０とされている。そして、内外筒金具１２，１４の軸方向両端部分において、それぞれ、内筒金具１２の軸方向延出部２８と外筒金具１４の軸方向延出部３０が径方向で離隔して対向位置せしめられている。
【００２７】
また、かかる一体加硫成形品２２には、本体ゴム弾性体１６の内周部分から軸方向両側に向かってそれぞれ円筒形状で延び出す一対の内側被覆ゴム３２，３２が形成されている。かかる一対の内側被覆ゴム３２，３２は、本体ゴム弾性体１６と一体形成されており、内筒金具１２における軸方向延び出し部２８，２８の外周面を被覆するように内筒金具１２に密着状態で加硫接着されている。なお、一対の内側被覆ゴム３２，３２は、全体に亘って略一定の厚さで形成されている。
【００２８】
また一方、本体ゴム弾性体１６の外周部分からも、軸方向両側に向かってそれぞれ円筒形状で延び出す一対の外側被覆ゴム３４，３４が形成されている。かかる一対の外側被覆ゴム３４，３４は、本体ゴム弾性体１６と一体形成されており、外筒金具１４の内周面を被覆するように外筒金具１４に密着状態で加硫接着されている。
【００２９】
さらに、各外側被覆ゴム３４には、内周面に開口する嵌合凹溝３６が、軸方向中間部分を周方向に延びるように形成されている。この嵌合凹溝３６は、図４にも示されているように、外筒金具１４の中心軸回りに広がる円筒面からなる底面３８と、該底面３８の軸方向両端部からそれぞれ径方向内方に向かって略直角に立ち上がる円環面からなる軸方向両側（軸方向内側および外側）の側壁面４０，４２を有しており、一定の断面形状で連続して全周に亘って延びるように形成されている。また、本実施形態では、嵌合凹溝３６の軸方向内側の側壁面４０よりも軸方向外側の側壁面４２の方が、径方向の突出高さが僅かに小さくされている。更に、嵌合凹溝３６の軸方向外側の壁部は、軸方向外方に行くに従って径方向の突出高さが次第に小さくされており、それによって、かかる軸方向外側の壁部の内周面が、軸方向外方に向かって拡開するテーパ状面４４とされている。なお、このことから明らかなように、本実施形態では、一対の外側被覆ゴム３４，３４によって保持ゴム層が構成されている。
【００３０】
また、嵌合凹溝３６の底壁部を形成する外側被覆ゴム３４には、嵌合凹溝３６の底面３８から径方向内方に向かって突出する弾性突部としての弾性突条４６が一体形成されている。この弾性突条４６は、嵌合凹溝３６の底面３８の幅寸法よりも十分に小さな幅寸法と、嵌合凹溝３６の軸方向両側の側壁面４０，４２よりも小さな突出高さを有している。そして、かかる弾性突条４６は、嵌合凹溝３６の幅方向略中央部分に位置して、略山形の断面形状をもって周方向の全周に亘って連続して延びるように形成されており、全体として環状のリップ形状を有している。
【００３１】
そうして、このような構造とされた一体加硫成形品２２には、図５に示されているように、一対の環状ストッパ部材としての環状ストッパ４８，４８が組み付けられている。かかる環状ストッパ４８は、略矩形の一定断面形状をもって周方向に延びる円環形状を有しており、その内径寸法は、内筒金具１２に被着形成された内側被覆ゴム３２の外径寸法よりも所定量だけ大きく設定されている。また一方、環状ストッパ４８の外径寸法は、外筒金具１４に被着形成された外側被覆ゴム３４に設けられた嵌合凹溝３６の底面３８の内径寸法よりも小さく、且つ、嵌合凹溝３６の底面３８に突設された弾性突条４６の突出先端部によって形成される円環状面の内径寸法よりも大きく設定されている。
【００３２】
なお、環状ストッパ４８は、金属や合成樹脂等の少なくとも本体ゴム弾性体１６よりも硬質の材料で形成されており、本実施形態では、ガラス繊維等で補強されたポリアミド樹脂等の硬質合成樹脂材で形成されている。
【００３３】
そして、かかる環状ストッパ４８，４８は、内外筒金具１２，１４間に軸方向両側から組み付けられて、嵌合凹溝３６の軸方向外側壁部をそのテーパ状面４４に沿って乗り越えることにより嵌め入れられており、各環状ストッパ４８の外周部分が、外側被覆ゴム３４に形成された嵌合凹溝３６に挿し入れられている。嵌合凹溝３６に挿し入れられた状態下で、環状ストッパ４８の外周面は、嵌合凹溝３６の底面から径方向内方に僅かに離隔位置せしめられており、環状ストッパ４８の外周面と嵌合凹溝３６の底面３８の間には僅かな間隙寸法：ｔをもって広がる隙間５０が形成されていると共に、環状ストッパ４８の外周面に対して弾性突条４６の先端部分が当接せしめられている。
【００３４】
また、環状ストッパ４８の軸方向長さは、嵌合凹溝３６の幅寸法と略同じとされており、それによって、嵌合凹溝３６に挿し入れられた環状ストッパの軸方向両端面に対して、それぞれ、嵌合凹溝３６の側壁面４０，４２が略密接状態で重ね合わされている。
【００３５】
ここにおいて、環状ストッパ４８を外筒金具１４の軸方向端部から挿入するに際しては、先ず、外筒金具１４の内周面に被着された外側被覆ゴム３４によって形成された嵌合凹溝３６の軸方向外側壁部を乗り越えさせる必要があるが、かかる嵌合凹溝３６の軸方向外側壁部の内周面には軸方向外方に拡開するテーパ状面４４が形成されていることから、環状ストッパ４８を軸方向内方に押し込むことにより、このテーパ状面４４で環状ストッパ４８が案内されて嵌合凹溝３６の軸方向外側壁部を容易に乗り越えさせることが出来る。そして、環状ストッパ４８を更に軸方向内方に押し込むことにより、環状ストッパ４８の軸方向内側面が、嵌合凹溝３６の軸方向内側面に対して当接せしめられる。この嵌合凹溝３６の軸方向内側面は、軸直角方向に広がる垂直な面をもって形成されていることから、環状ストッパ４８の乗り越えが防止されて、環状ストッパ４８の軸方向内方への押し込み端が規制されることとなる。しかも、環状ストッパ４８を嵌合凹溝３６の軸方向内側面に当接させて更に少し軸方向内方に押し込むと、嵌合凹溝３６の軸方向内側壁部が弾性変形せしめられて嵌合凹溝３６の溝幅が広がる結果、環状ストッパ４８が、嵌合凹溝３６の軸方向外側壁部を完全に乗り越えて嵌合凹溝３６に挿し入れられた状態とされる。その後、環状ストッパ４８に対する軸方向内方への押し込み力を解除すると、環状ストッパ４８の軸方向両端面に対して嵌合凹溝３６の軸方向内側壁面４０と軸方向外側壁面４２が重ね合わせられて、環状ストッパ４８の外周部分が嵌合凹溝３６に嵌め込まれたままの状態で軸方向に有利に位置決め保持され得ることとなる。
【００３６】
特に、嵌合凹溝３６の軸方向内外壁面４０，４２は、何れも軸直角方向に広がる垂直面とされていることから、環状ストッパ４８に対する軸方向の保持力が有利に発揮され得るのであり、また、環状ストッパ４８の軸方向外面に対する嵌合凹溝３６の軸方向外側壁部の重なり状態も、外部から容易に見て、或いは触って確認することが出来るのである。しかも、環状ストッパ４８は、嵌合凹溝３６の底面３８に突設された弾性突条４６が外周面に当接されることにより、径方向でも外筒金具１４の中心軸上に保持されていることから、環状ストッパ４８の軸方向両端面に対する嵌合凹溝３６の軸方向両壁面４０，４２の重ね合わせ状態が一層有利に保たれて、環状ストッパ４８の嵌合凹溝３６からの抜け出しが防止されるのである。
【００３７】
さらに、このようにして一体加硫成形品２２に一対の環状ストッパ４８，４８を組み付けた組付体５２に対しては、その外筒金具１４に縮径加工が施されている。かかる縮径加工は、例えば周方向に８分割や１６分割等した絞り金型を用いて外筒金具１４の外周面に径方向内方に向かう圧力を加える周知の絞り加工を行なうことによって、有利に為され得る。
【００３８】
そして、外筒金具１４に縮径加工を施して、外筒金具１４の全体を縮径させることにより、図１〜２に示されている如き目的とするサスペンションブッシュ１０とされている。ここにおいて、外筒金具１４の縮径加工により、外筒金具の内周面に被着された外側被覆ゴム３４も縮径されており、嵌合凹溝３６の底面３８に突設された弾性突条４６が環状ストッパ４８への当接圧で潰されて、環状ストッパ４８の外周面の全体が嵌合凹溝３６の底面３８に対して大きな圧力をもって当接されて嵌着固定されている。即ち、環状ストッパ４８には、外側被覆ゴム３４に対する当接面の摩擦力だけでなく、環状ストッパ４８の当接によって軸方向外側に押し広げられるようにして弾性変形せしめられた外側被覆ゴム３４の弾性に基づく復元力も作用せしめられることとなり、全体として大きな力で環状ストッパ４８が外筒金具１４に対して軸方向に位置決め保持されているのである。
【００３９】
また、環状ストッパ４８は、嵌合凹溝３６に挿し入れられた嵌合状態に保たれたままで、外筒金具１４に縮径加工が施されることから、かかる縮径加工に際しても、環状ストッパ４８が嵌合凹溝３６への嵌合状態に安定して保持され得ることとなり、環状ストッパ４８が位置決めされた状態のままで外筒金具１４が縮径されることにより、外筒金具１４に対して環状ストッパ４８が高い位置決め精度で最終的に固定されるのである。
【００４０】
なお、図１〜２から明らかなように、環状ストッパ４８の内径寸法は、内筒金具１２に被着された内側被覆ゴム３２の外径寸法よりも十分に大きくされており、環状ストッパ４８の内周面が内側被覆ゴム３２の外周面に対して、径方向で所定距離：Ｔだけ離隔して対向位置せしめられている。また、環状ストッパ４８の軸方向長さは、外側被覆ゴム３４の軸方向長さよりも十分に小さくされており、環状ストッパ４８が、本体ゴム弾性体１６から軸方向に十分に離隔して位置せしめられている。
【００４１】
そして、このような構造とされたサスペンションブッシュ１０は、図１に仮想線で示されているように、内筒金具１２に挿通せしめた取付ロッド５４によって内筒金具１２をサスペンションアーム１８に対して取付ボルト５５により固定的に取り付ける一方、サスペンションメンバ２０に形成された装着孔５６に外筒金具１４を圧入固定することによって、サスペンションアーム１８のサスペンションメンバ２０に対する取付部位に介装されて、サスペンションアーム１８をサスペンションメンバ２０に対して防振連結せしめることとなる。なお、図１中、内筒金具１２の軸方向両側には、円環板形状の緩衝プレート５３，５３がサスペンションアーム１８または内筒金具１２に外挿されて装着されており、外筒金具１４がこれら緩衝ゴムプレート５３，５３を介してサスペンションメンバ２０に固設された当接部材５７，５８に当接せしめられることにより、軸方向のストッパ機能が発揮されるようになっている。
【００４２】
また、かかる装着状態下では、軸方向や軸直角方向、或いはこじり方向等の各種方向への振動荷重がサスペンションブッシュ１０の内外筒金具１２，１４間に及ぼされることとなるが、軸直角方向に大きな荷重が及ぼされた際には、外筒金具１４に嵌着固定された環状ストッパ４８の内周面が、内側被覆ゴム３２を介して、内筒金具１２に対して当接せしめられることとなり、その結果、本体ゴム弾性体１６の過大な変形や内外筒金具１２，１４の過大な相対変位が緩衝的に制限されて有効なストッパ機能が発揮されるのである。なお、このことから明らかなように、本実施形態では、内側被覆ゴム３２によって、環状ストッパ４８の内筒金具１２への当接を緩衝する緩衝ゴム層が構成されている。また、内外筒金具１２，１４間に大きな荷重が入力された際にも、環状ストッパ４８の本体ゴム弾性体１６に対する干渉が回避されるように、本体ゴム弾性体１６と環状ストッパ４８，４８の間には十分な隙間が形成されている。
【００４３】
特に、上述の如き構造とされたサスペンションブッシュ１０においては、環状ストッパ４８を一体加硫成形品２２に組み付ける際に、外側被覆ゴム３４に形成された嵌合凹溝３６に挿し入れるようにしたことにより、嵌合凹溝３６を予め設定された軸方向位置に正確にセットすることが可能であり、かかるセット状態を、軸方向外方から視認等で容易に確認することも出来る。それ故、環状ストッパ４８のセットを、優れた作業性をもって安定して行なうことが可能となって、製品の性能安定性と信頼性が飛躍的に向上されることとなり、特別な作業上の負荷を伴うことなく、不良品の発生を大幅に減ずることが出来るのである。
【００４４】
以上、本発明の実施形態について詳述してきたが、これはあくまでも例示であって、本発明はかかる実施形態における具体的な記載によって、何等、限定的に解釈されるものでなく、当業者の知識に基づいて種々なる改良，修正等を加えた態様において実施され得るものであり、また、一々列挙しないが、そのような実施態様が本発明の趣旨を逸脱しない限り、何れも、本発明の範囲内に含まれるものであることは言うまでもない。
【００４５】
例えば、図６に示されているように、環状ストッパ４８の径方向内方への突出高さを周方向で変化させることにより、互いに異なる径方向で発揮されるストッパ機能をチューニングすることも可能である。
【００４６】
また、図７に示されているように、鉄鋼等の金属よりも容易に変形する合成樹脂製のアウタ筒部材６０を採用して、特別な金型等によるサスペンションブッシュ単体への縮径加工を行なうことなく、装着孔５６へのアウタ筒部材６０の圧入によってアウタ筒部材６０を所定量だけ縮径させることにより、最終的な装着状態下で環状ストッパ４８をアウタ筒部材６０に対して嵌着固定せしめるようにすることも可能である。なお、このように最終的な装着時にアウタ筒部材６０に対する縮径と、それに伴う環状ストッパ４８のアウタ筒部材６０への嵌着固定を行なうようにする場合には、環状ストッパ４８を嵌合凹溝３６に挿し入れただけで、未だアウタ筒部材６０の縮径による最終的な環状ストッパ４８の嵌着固定が施されていない状態で、サスペンションブッシュを製品として装着工程に提供するようにされることは、言うまでもない。
【００４７】
また、嵌合凹溝３６の底面３８における弾性突条４６は、嵌合凹溝３６の軸方向両側の側壁面４０，４２の高さや、外筒金具１４に対する縮径率等を考慮して必要に応じて採用されるものであって、本発明に必須のものでない。
【００４８】
また、環状ストッパ４８を嵌合凹溝３６に挿し入れた状態下で、環状ストッパ４８の外周面と嵌合凹溝３６の底面３８の間に形成される隙間５０も、外筒金具１４に対する縮径率や、嵌合凹溝３６の底壁を形成する外側被覆ゴム３４の厚さ寸法等を考慮して必要に応じて採用されるものであって、本発明に必須のものでない。
【００４９】
更にまた、前記実施形態では、内外筒金具１２，１４の軸方向両側に一対の環状ストッパ４８，４８が組み付けられていたが、例えば前記特開平９−２８０３１４号公報等に記載の防振ブッシュでは、軸方向一方の側にだけ環状ストッパ部材を組み付けた態様が好適に採用され得る。
【００５０】
また、最終状態において環状ストッパ４８の外筒金具１４からの抜け出しをより有効に防止するために、例えば、図８に示されているように、外筒金具１４の軸方向開口端部だけ縮径量を大きくして、環状ストッパ４８に対して係止作用を為すカシメ状部６０を形成しても良い。
【００５１】
加えて、前記実施形態では、本発明をサスペンションブッシュに適用したものの一具体例を示したが、本発明は、その他、自動車用の筒型マウントを含む各種の防振ブッシュ、更に自動車以外の各種装置に用いられる多様な防振ブッシュに対して、何れも適用可能であることは、言うまでもない。
【００５２】
【発明の効果】
上述の説明から明らかなように、本発明に従う構造とされた防振ブッシュにおいては、アウタ筒部材の内周面に被着形成された保持ゴム層に対して嵌合凹溝を形成し、この嵌合凹溝に環状ストッパ部材を挿し入れて組み付けるようにしたことから、環状ストッパ部材を正確な位置に対して容易に組み付けることが出来、その確認も容易となる。しかも、最終的にアウタ筒部材を縮径して環状ストッパ部材をアウタ筒金具に嵌着固定する前の工程での環状ストッパ部材の位置ずれが有利に防止され得て、環状ストッパ部材をアウタ筒部材に対して高い位置精度で嵌着固定することが出来るのであり、確認や組付けの製造工程上での作業負担の増加を伴うことなく、防振ブッシュの性能の安定性と信頼性が大幅に向上され得るのである。
【図面の簡単な説明】
【図１】本発明の第一の実施形態としてのサスペンションブッシュを示す縦断面説明図である。
【図２】図１における右側面図である。
【図３】図１に示されたサスペンションブッシュを構成する一体加硫成形品を示す縦断面図である。
【図４】図３に示された一体加硫成形品の要部拡大説明図である。
【図５】図１に示されたサスペンションブッシュの一製造工程を説明するための組付体の縦断面図である。
【図６】本発明の別の具体的態様例を示す、図２に対応する右側面図である。
【図７】本発明の更に別の具体的態様例を示す、図１に対応する縦断面説明図である。
【図８】本発明の更に別の具体的態様例を示す縦断面図である。
【符号の説明】
１０サスペンションブッシュ
１２内筒金具
１４外筒金具
１６本体ゴム弾性体
２２一体加硫成形品
２８軸方向延出部
３０軸方向延出部
３２内側被覆ゴム
３４外側被覆ゴム
３６嵌合凹溝
３８底面
４０側壁面（軸方向内側）
４２側壁面（軸方向外側）
４６弾性突条
４８環状ストッパ
５０隙間
５２組付体[0001]
【Technical field】
The present invention relates to an anti-vibration bush having a structure in which an inner shaft member and an outer cylinder member, which are spaced apart from each other in the radial direction, are connected by a main rubber elastic body, for example, a suspension bush for an automobile, a subframe mount, a body mount, etc. The present invention relates to an anti-vibration bush that can be employed.
[0002]
[ Background art ]
Conventionally, as one type of vibration isolator interposed between members constituting a vibration transmission system, as described in, for example, Japanese Patent Laid-Open Nos. 11-2289 and 9-280314, an inner shaft The outer cylinder member is spaced apart radially outward of the member, and a main rubber elastic body is disposed between the radially opposed surfaces of the inner shaft member and the outer cylinder member so that the main rubber is attached to the inner shaft member and the outer cylinder member. An anti-vibration bush having a structure in which an inner shaft member and an outer cylinder member are elastically connected by vulcanizing and bonding an elastic body is known.
[0003]
Further, in such an anti-vibration bush, a stopper mechanism that restricts the amount of elastic deformation of the main rubber elastic body when a large radial load is applied between the inner shaft member and the outer cylindrical member may be employed. As one of such stopper mechanisms, as described in the above publication, an annular stopper is fitted and fixed to the outer cylindrical member, and the inner peripheral surface of the annular stopper is radially oriented with respect to the inner shaft member. The structure of the structure which was made to oppose at a predetermined distance is proposed. In such a stopper mechanism, a holding rubber layer is formed on the inner peripheral surface of the outer cylindrical member, and an annular stopper is inserted and arranged on the inner peripheral surface of the holding rubber layer, and then the outer cylindrical member is reduced by drawing or the like. By making the diameter, the annular stopper is fitted and fixed to the outer cylinder member via the holding rubber layer. In other words, by interposing the holding rubber layer, it is possible to absorb variations in the diameter reduction of the outer cylindrical member, dimensional errors of the annular stopper, etc., and to stabilize the annular stopper with respect to the outer cylindrical member while avoiding damage to the annular stopper. Thus, it can be fitted and fixed.
[0004]
By the way, when the annular stopper is fitted and fixed to the outer cylinder member, a desired stopper function can be stably obtained by abutting the annular stopper on the inner shaft member side, and the annular stopper can be buffered to other members. In order to avoid this, it is required to accurately fix the annular stopper at a predetermined position set in advance in the outer cylinder member.
[0005]
However, in the vibration isolating bush having the conventional structure as described in the above publication, the positioning of the annular stopper with respect to the outer cylinder member is not taken into consideration at all, and the annular stopper is accurately inserted when the annular stopper is inserted into the outer cylinder member. There was a problem that it was difficult to position.
[0006]
Moreover, since the annular stopper is not held at a predetermined position after being inserted into the outer cylinder member, even if the annular stopper is inserted into the outer cylinder member at an accurate position, the subsequent outer stopper There has also been a problem that the annular stopper is likely to be displaced with respect to the outer cylindrical member during operations such as conveyance and eight-way drawing during diameter reduction processing of the cylindrical member.
[0007]
In particular, in order to avoid damage to the annular stopper when the outer cylinder member is reduced in diameter when the diameter reduction amount of the outer cylinder member is set large in order to improve the durability of the main rubber elastic body, the spring characteristics, etc. In addition, there is a case where a gap is set between the outer cylindrical member and the radial direction of the annular stopper inserted therein, and when such a gap is formed, the positioning when inserting the annular stopper into the outer cylindrical member or Positioning after insertion becomes even more difficult. Further, as described in JP-A-11-2289, when assembling the annular stoppers at both axial ends of the outer cylinder member, the outer cylinder member is inserted after inserting the annular stopper into the outer cylinder member. Since any of the annular stoppers may come out and fall off even if it is tilted in any axial direction, the position where the annular stopper is intended rather than the case where the annular stopper is assembled only at one axial end portion of the outer cylinder member. It becomes even more difficult to fit and fix accurately.
[0008]
In order to accurately align the annular stopper when the annular stopper is inserted into the outer cylinder member, for example, a step surface is formed on the holding rubber layer, and the axial end surface on the insertion side of the annular stopper is the step surface. It is also conceivable to define the insertion end of the annular stopper into the outer cylinder member by abutting with the outer cylindrical member. However, since such a stepped surface becomes invisible from the outside when the annular stopper is inserted, there is a problem that the work itself for checking whether the annular stopper is in contact with the stepped surface is troublesome and difficult. Yes, it is not yet an effective solution.
[0009]
[Solution]
Here, the present invention has been made in the background as described above, and the problem to be solved is that the annular stopper member constituting the radial stopper mechanism can be easily attached to the outer cylinder member. An object of the present invention is to provide an anti-vibration bush having a novel structure that can be fitted and fixed with good positional accuracy.
[0010]
[Solution]
Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. In addition, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized on the basis of.
[0011]
That is, the feature of the first aspect of the present invention is that the outer cylindrical member is spaced apart radially outward of the inner shaft member, and between the radially opposing surfaces of the inner shaft member and the outer cylindrical member. An anti-vibration bushing in which a main rubber elastic body is disposed and the main rubber elastic body is vulcanized and bonded to the outer peripheral surface of the inner shaft member and the inner peripheral surface of the outer cylinder member, respectively, At least one end portion in the axial direction of the outer cylindrical member is formed with axially extending portions that extend in the axial direction from the connecting portion by the main rubber elastic body and are opposed to each other in the radial direction. A holding rubber layer extending on the inner peripheral surface of the axially extending portion of the main body is formed integrally with the main rubber elastic body, and the fitting rubber groove extends radially inwardly in the holding rubber layer and extends in the circumferential direction. Is formed Together, are allowed disposed encased inserted an annular stopper member to the fitting groove, the annular stopper member is positioned and held in the axial direction both side walls of the fitting groove, Holding the annular stopper member The outer cylindrical member is deformed in a reduced diameter, and the annular stopper member is fitted and fixed to the outer cylindrical member. ing Located in anti-vibration bush.
[0012]
In the anti-vibration bush having the structure according to the present invention as described above, the retaining rubber layer is formed with a fitting concave groove that is located on the inner peripheral surface of the outer cylindrical member to which the annular stopper member is assembled and extends in the circumferential direction. Thus, the annular stopper member is inserted into the fitting groove, and the both axial end surfaces of the annular stopper member are held so as to be supported by both axial side walls of the fitting groove. Therefore, just by inserting the annular stopper member into the fitting concave groove, the annular stopper member is accurately positioned at a predetermined target position in the outer cylinder member, and the axial displacement is prevented. It can be held. Moreover, since the fitting groove is formed of a holding rubber layer, the annular stopper member can be easily and quickly moved to the fitting groove by elastic deformation of the axially outer wall portion of the fitting groove. It can be inserted and assembled, making it easy to manufacture.
[0013]
In addition, under the state in which the annular stopper member is correctly inserted into the fitting groove, the axially outer wall portion of the fitting groove is made to rise along the axial outer surface of the annular stopper member. Whether or not the annular stopper member is correctly inserted into the fitting concave groove when assembling the annular stopper member can be easily determined by visual recognition from the outside. The assembly to the position can be performed more reliably.
[0014]
In this embodiment, one or both of the side walls in the axial direction of the fitting groove may be formed in a form divided in the circumferential direction, but preferably continuously over the entire circumference in the circumferential direction. It is formed. Further, the both side wall portions in the axial direction in the fitting groove are not necessarily the same in the radial rising height, and are arbitrary, for example, more axial than the side wall portion on the outer side in the axial direction of the fitting groove. By raising the inner wall in the direction to the inner side in the radial direction, the annular stopper member can be easily inserted into the fitting concave groove, and the annular stopper member can be inserted inward in the axial direction. The end position can be more advantageously defined.
[0015]
Further, in the vibration isolating bushing according to the present aspect, the annular stopper member is fitted and fixed to the outer cylindrical member via the holding rubber layer by reducing the diameter of the outer cylindrical member at least in a final mounted state. However, in the state before the outer cylinder member is reduced in diameter, the annular stopper member only needs to be positioned and held with respect to the outer cylinder member by being inserted into the fitting groove, for example, the outer periphery of the annular stopper member There may be some backlash or gap in the radial direction between the surface and the bottom surface of the fitting groove.
[0016]
Furthermore, the anti-vibration bushing according to this aspect, in the manufacturing process of the anti-vibration bushing alone, after inserting the annular stopper member into the fitting concave groove, the outer cylindrical member is subjected to diameter reduction processing such as an eight-way drawing, The outer peripheral surface of the annular stopper member may be pressed against the outer cylinder member via the holding rubber layer, and the annular stopper member may be fixed to the outer cylinder member. After the insertion, the anti-vibration bushing is supplied as a single product before or after the annular stopper member is fixed to the outer cylindrical member due to the diameter reduction of the outer cylindrical member, and the anti-vibration bushing is connected with the anti-vibration bushing. When the outer cylinder member of the vibration isolating bush is press-fitted and fixed to the mounting hole of the vibration isolating bush such as the arm eye formed on one member, the outer cylinder member is reduced in diameter, Annular stopper member with the assembly completion of vibration damping bushes to wear holes may be is fitted fixed to the outer cylindrical member. In particular, when the outer cylindrical member is reduced in diameter by press-fitting the outer cylindrical member into the mounting hole and the annular stopper member is fitted and fixed to the outer cylindrical member, the outer cylindrical member is made of metal such as steel. A synthetic resin or the like can also be advantageously employed.
[0017]
Further, in the vibration isolating bush according to this aspect, the annular stopper member is formed of at least a synthetic resin or metal harder than the main rubber elastic body, and the inner shaft member in the main rubber elastic body is used. It is desirable that the outer cylinder member be disposed apart from the connecting portion in the axial direction so as to avoid interference with the connecting portion. Furthermore, it is desirable to assemble a pair of annular stopper members at both axial ends of the outer cylinder member so as to be positioned on both sides in the axial direction across the connecting portion between the inner shaft member and the outer cylinder member in the main rubber elastic body. Thereby, the action of the twisting direction load on the inner shaft member and the outer cylinder member when the annular stopper member is brought into contact with the inner shaft member side can be reduced or avoided. In addition, it is desirable to form a buffer rubber layer on the outer peripheral surface of the inner shaft member against which the inner peripheral surface of the annular stopper member is brought into contact, and preferably the buffer rubber layer is integrally formed with the main rubber elastic body. However, a buffer rubber layer may be attached to the inner peripheral surface of the annular stopper member.
[0018]
According to a second aspect of the present invention, in the vibration-proof bushing according to the first aspect, an elastic protrusion is formed on a bottom surface of the fitting groove, and the annular stopper member is formed with respect to the elastic protrusion. It is characterized in that the outer peripheral surface of the part is brought into partial contact. In the anti-vibration bush having the structure according to this aspect, for example, it is necessary to increase the diameter reduction of the outer cylindrical member and apply effective pre-compression to the main rubber elastic body. Even when a large gap is formed between the bottom surface of the ring and the radial direction of the annular stopper member inserted therein, the annular stopper member inserted into the fitting concave groove is stably held by the elastic protrusion, and the annular stopper It is possible to effectively suppress the member from coming out of the fitting groove.
[0019]
In addition, in this aspect, if an elastic protrusion partly contact | abuts with respect to the outer peripheral surface of an annular stopper member, if it exerts an effective radial positioning holding force with respect to an annular stopper member, For example, it may be advantageously configured by a plurality of protrusions formed on the bottom surface of the fitting groove, or a circumferential ridge extending in the circumferential direction formed on the bottom surface of the fitting groove. In particular, if an elastic protrusion that continuously extends over a predetermined length in the circumferential direction or over the entire circumference is employed, a more effective radial positioning and holding force can be applied to the annular stopper member.
[0020]
Moreover, the 3rd aspect of this invention is an internal peripheral surface in the wall part of the axial direction outer side of the said fitting ditch | groove formed by the said holding | maintenance rubber layer in the vibration-proof bushing which concerns on the said 1st or 2nd aspect. Is a taper surface that expands outward in the axial direction. In the anti-vibration bush having the structure according to this aspect, when the annular stopper member is inserted into the fitting groove, the annular stopper member is fitted over the axially outer wall portion of the fitting groove. It becomes easier to introduce the groove and the intended vibration-proof bushing can be performed more easily and efficiently.
[0021]
According to a fourth aspect of the present invention, in the vibration-proof bushing according to any one of the first to third aspects, the outer cylinder member is formed of a metal outer cylinder fitting, and the outer cylinder fitting is used. The annular stopper member is fitted and fixed to the outer cylinder fitting by reducing the diameter. In such an anti-vibration bush according to this aspect, the pre-compression of the outer tube bracket and thus the main rubber elastic body can be set sufficiently large. It is also possible to easily reduce the diameter of the outer tube fitting with a diameter reduction amount of 3% or more, particularly preferably 5% or more, and more preferably 10% or more. It should be noted that the diameter reduction processing for the outer cylinder fitting can be advantageously performed by an eight-way stop or the like in the state of the vibration isolating bush alone before the vibration isolating bush is attached to the vibration member to be anti-vibrated.
[0022]
According to a fifth aspect of the present invention, there is provided the vibration isolating bush according to any one of the first to fourth aspects, wherein the annular stopper member is directed from the outer cylinder member side to the inner shaft member side. The projecting height in the radial direction is different in the circumferential direction. In the anti-vibration bush having the structure according to this aspect, the function of limiting the relative displacement in the radial direction of the inner shaft member and the outer cylindrical member can be provided with different characteristics in a plurality of radial directions. For example, it is possible to advantageously cope with a case where the inner shaft member and the outer cylinder member are disposed in the initial state so as to be biased in the radial direction.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
First, FIGS. 1 and 2 show an automobile suspension bush 10 as a vibration-proof bushing according to a first embodiment of the present invention. The suspension bush 10 is formed by elastically connecting an inner cylinder fitting 12 as an inner shaft member and an outer cylinder fitting 14 as an outer cylinder member by a main rubber elastic body 16. For example, as shown in phantom lines in FIG. 1, the suspension bush 10 has an inner cylindrical metal member 12 fixed to a suspension arm 18 of an automobile and an outer portion of a suspension member 20 of the automobile. By fixing the tubular fitting 14, the suspension arm 18 is connected to the suspension member 20 in a vibration-proof manner. In the following description, the axial direction and the radial direction refer to the axial direction and the radial direction of the inner cylinder fitting 12 or the outer cylinder fitting 14 in principle.
[0025]
More specifically, the inner cylinder fitting 12 has a straight cylindrical shape and is formed of a metal material such as steel. On the other hand, the outer cylinder fitting 14 has a straight cylindrical shape having a larger diameter than the inner cylinder fitting 12 by a predetermined amount, and is formed of an appropriate metal material like the inner cylinder fitting 12. And the outer cylinder metal fitting 14 is extrapolated by the inner cylinder metal fitting 12, and the outer cylinder metal fitting 14 is spaced apart from the inner cylinder metal fitting 12 in the radial direction by a predetermined distance and is disposed on substantially the same central axis. . The inner cylinder fitting 12 is longer in the axial direction than the outer cylinder fitting 14, and the axial end of the inner cylinder fitting 12 is protruded axially outward from the outer cylinder fitting 14.
[0026]
A main rubber elastic body 16 is disposed between the radially opposing surfaces of the inner cylinder fitting 12 and the outer cylinder fitting 14. The main rubber elastic body 16 has a substantially annular block shape, and is positioned substantially at the center in the axial direction of the inner and outer cylinder fittings 12 and 14 and between the radially opposing surfaces of the inner and outer cylinder fittings 12 and 14. It is arranged across. Further, the inner and outer peripheral surfaces of the main rubber elastic body 16 are vulcanized and bonded to the outer peripheral surface of the inner cylindrical fitting 12 and the inner peripheral surface of the outer cylindrical fitting 14, respectively. The main rubber elastic body 16 is elastically connected at a substantially central portion in the axial direction. As is apparent from this, in the present embodiment, the main rubber elastic body 16 is formed as an integral vulcanized molded product 22 having inner and outer cylindrical fittings 12 and 14 as shown in FIG. Yes. Further, both axial side portions of the inner cylindrical metal member 12 and both axial side portions of the outer cylindrical metal member 14 are axially outward from the substantially central portions 24 and 26 in the axial direction, which are connected portions by the main rubber elastic body 16, respectively. The extended axially extending portions 28, 28 and 30, 30 are provided. Then, at both axial end portions of the inner and outer cylindrical fittings 12 and 14, the axially extending portion 28 of the inner cylindrical fitting 12 and the axially extending portion 30 of the outer cylindrical fitting 14 are spaced apart from each other in the radial direction. It has been.
[0027]
In addition, the integral vulcanized molded product 22 is formed with a pair of inner covering rubbers 32 and 32 extending in a cylindrical shape from the inner peripheral portion of the main rubber elastic body 16 toward both axial sides. The pair of inner covering rubbers 32 and 32 are formed integrally with the main rubber elastic body 16 and are in close contact with the inner cylinder fitting 12 so as to cover the outer peripheral surfaces of the axially extending portions 28 and 28 of the inner cylinder fitting 12. It is vulcanized and bonded in the state. The pair of inner covering rubbers 32, 32 are formed with a substantially constant thickness throughout.
[0028]
On the other hand, a pair of outer covering rubbers 34 and 34 are formed from the outer peripheral portion of the main rubber elastic body 16 so as to extend in a cylindrical shape toward both sides in the axial direction. The pair of outer covering rubbers 34 and 34 are integrally formed with the main rubber elastic body 16, and Inner circumference It is vulcanized and bonded in close contact with the outer tube fitting 14 so as to cover the surface.
[0029]
Further, each outer covering rubber 34 is formed with a fitting concave groove 36 opened to the inner peripheral surface so as to extend in the circumferential direction at an axially intermediate portion. As shown in FIG. 4, the fitting concave groove 36 has a bottom surface 38 formed of a cylindrical surface extending around the central axis of the outer cylinder fitting 14, and a radially inner portion from both axial ends of the bottom surface 38. Side wall surfaces 40 and 42 on both sides in the axial direction (inner and outer sides in the axial direction) composed of annular surfaces rising substantially at right angles toward the direction so as to continuously extend over the entire circumference with a constant cross-sectional shape. Is formed. In the present embodiment, the axially outer side wall surface 42 is slightly smaller in the radial protrusion height than the axially inner side wall surface 40 of the fitting groove 36. Further, the axially outer wall portion of the fitting groove 36 has a radially projecting height that gradually decreases outward in the axial direction, whereby the inner peripheral surface of the axially outer wall portion is reduced. Is a tapered surface 44 that expands outward in the axial direction. As is apparent from this, in this embodiment, the holding rubber layer is constituted by the pair of outer covering rubbers 34 and 34.
[0030]
The outer covering rubber 34 forming the bottom wall portion of the fitting groove 36 is integrally provided with an elastic protrusion 46 as an elastic protrusion protruding radially inward from the bottom surface 38 of the fitting groove 36. Is formed. The elastic protrusion 46 has a width dimension sufficiently smaller than the width dimension of the bottom surface 38 of the fitting groove 36 and a protruding height smaller than the side wall surfaces 40 and 42 on both axial sides of the fitting groove 36. is doing. And this elastic protrusion 46 is located in the width direction substantially center part of the fitting ditch | groove 36, and is formed so that it may extend continuously over the perimeter of a circumferential direction with a substantially chevron-shaped cross-sectional shape, As a whole, it has an annular lip shape.
[0031]
Then, as shown in FIG. 5, annular stoppers 48, 48 as a pair of annular stopper members are assembled to the integrally vulcanized molded product 22 having such a structure. The annular stopper 48 has an annular shape extending in the circumferential direction with a substantially rectangular constant cross-sectional shape, and the inner diameter dimension thereof is larger than the outer diameter dimension of the inner covering rubber 32 formed on the inner cylinder fitting 12. Is also set larger by a predetermined amount. On the other hand, the outer diameter dimension of the annular stopper 48 is smaller than the inner diameter dimension of the bottom surface 38 of the fitting groove 36 provided in the outer covering rubber 34 formed on the outer cylinder fitting 14 and is fitted into the fitting recess. It is set to be larger than the inner diameter dimension of the annular surface formed by the projecting tip of the elastic protrusion 46 projecting from the bottom surface 38 of the groove 36.
[0032]
The annular stopper 48 is made of a material harder than at least the main rubber elastic body 16 such as a metal or a synthetic resin. In this embodiment, a hard synthetic resin material such as a polyamide resin reinforced with glass fiber or the like is used. It is formed with.
[0033]
The annular stoppers 48, 48 are assembled between the inner and outer cylindrical fittings 12, 14 from both sides in the axial direction, and are fitted by climbing over the axially outer wall portion of the fitting groove 36 along the tapered surface 44. The outer peripheral portion of each annular stopper 48 is inserted into a fitting groove 36 formed in the outer covering rubber 34. Under the state of being inserted into the fitting groove 36, the outer peripheral surface of the annular stopper 48 is slightly spaced radially inward from the bottom surface of the fitting groove 36. And a bottom surface 38 of the fitting groove 36 is formed with a gap 50 having a slight gap dimension t, and the tip of the elastic protrusion 46 is brought into contact with the outer peripheral surface of the annular stopper 48. It has been.
[0034]
Further, the axial length of the annular stopper 48 is substantially the same as the width dimension of the fitting groove 36, so that the axial length of both ends of the annular stopper inserted into the fitting groove 36 is reduced. Thus, the side wall surfaces 40 and 42 of the fitting concave groove 36 are overlapped in a substantially tight state.
[0035]
Here, when the annular stopper 48 is inserted from the axial end of the outer cylinder fitting 14, first, the fitting concave groove 36 formed by the outer covering rubber 34 attached to the inner peripheral surface of the outer cylinder fitting 14. However, it is necessary to form a tapered surface 44 that expands outward in the axial direction on the inner peripheral surface of the axially outer wall portion of the fitting groove 36. Then, by pushing the annular stopper 48 inward in the axial direction, the annular stopper 48 is guided by the tapered surface 44, and the axially outer wall portion of the fitting groove 36 can be easily climbed over. Then, by pushing the annular stopper 48 further inward in the axial direction, the axial inner surface of the annular stopper 48 is brought into contact with the axial inner surface of the fitting groove 36. Since the inner side surface in the axial direction of the fitting groove 36 is formed with a vertical surface extending in the direction perpendicular to the axis, the annular stopper 48 is prevented from getting over, and the annular stopper 48 is pushed inward in the axial direction. The end will be regulated. Moreover, when the annular stopper 48 is brought into contact with the inner side surface in the axial direction of the fitting groove 36 and further pushed inward in the axial direction, the inner wall portion in the axial direction of the fitting groove 36 is elastically deformed and fitted. As a result of the groove width of the groove 36 being widened, the annular stopper 48 is completely inserted over the axially outer wall portion of the fitting groove 36 and inserted into the fitting groove 36. Thereafter, when the pushing force inward in the axial direction with respect to the annular stopper 48 is released, the axially inner wall surface 40 and the axially outer wall surface 42 of the fitting groove 36 are overlapped with both axial end surfaces of the annular stopper 48. Thus, the outer peripheral portion of the annular stopper 48 can be advantageously positioned and held in the axial direction while being fitted in the fitting groove 36.
[0036]
In particular, since the inner and outer wall surfaces 40 and 42 in the axial direction of the fitting groove 36 are both vertical surfaces extending in the direction perpendicular to the axis, the holding force in the axial direction with respect to the annular stopper 48 can be exerted advantageously. Moreover, the overlapping state of the axially outer wall portion of the fitting groove 36 with respect to the axially outer surface of the annular stopper 48 can also be easily seen or touched from the outside. In addition, the annular stopper 48 is held on the central axis of the outer cylindrical metal member 14 in the radial direction by the elastic protrusion 46 projecting from the bottom surface 38 of the fitting groove 36 being brought into contact with the outer peripheral surface. Therefore, the overlapping state of both axial wall surfaces 40, 42 of the fitting groove 36 with respect to the both axial end surfaces of the annular stopper 48 is more advantageously maintained, and the annular stopper 48 comes out of the fitting groove 36. Is prevented.
[0037]
Further, for the assembly 52 in which the pair of annular stoppers 48, 48 are assembled to the integrally vulcanized molded product 22 in this way, the outer cylinder fitting 14 is subjected to diameter reduction processing. Such diameter reduction is advantageous, for example, by performing a known drawing process in which a radially inward pressure is applied to the outer peripheral surface of the outer tube fitting 14 using a drawing die that is divided into eight or sixteen pieces in the circumferential direction. Can be done.
[0038]
Then, the outer cylinder fitting 14 is subjected to a diameter reduction process to reduce the diameter of the entire outer cylinder fitting 14, thereby obtaining the target suspension bush 10 as shown in FIGS. Here, the outer covering rubber 34 attached to the inner peripheral surface of the outer cylinder fitting is also reduced in diameter by the diameter reduction processing of the outer cylinder fitting 14, and elastically protruded from the bottom surface 38 of the fitting groove 36. The protrusion 46 is crushed by the contact pressure against the annular stopper 48, and the entire outer peripheral surface of the annular stopper 48 is brought into contact with the bottom surface 38 of the fitting groove 36 with a large pressure and is fixedly fitted. . In other words, the annular stopper 48 has not only the frictional force of the contact surface with the outer covering rubber 34 but also the outer covering rubber 34 elastically deformed so as to be spread outward in the axial direction by the contact of the annular stopper 48. A restoring force based on elasticity is also applied, and the annular stopper 48 is positioned and held in the axial direction with respect to the outer cylinder fitting 14 with a large force as a whole.
[0039]
Further, the annular stopper 48 is subjected to the diameter reduction process on the outer cylindrical fitting 14 while being kept in the fitted state inserted into the fitting concave groove 36. 48 can be stably held in the fitted state in the fitting concave groove 36, and the outer cylinder fitting 14 is reduced in diameter while the annular stopper 48 is positioned. On the other hand, the annular stopper 48 is finally fixed with high positioning accuracy.
[0040]
As is clear from FIGS. 1 and 2, the inner diameter dimension of the annular stopper 48 is sufficiently larger than the outer diameter dimension of the inner covering rubber 32 attached to the inner cylinder fitting 12. The inner peripheral surface is opposed to the outer peripheral surface of the inner covering rubber 32 by being separated by a predetermined distance: T in the radial direction. The axial length of the annular stopper 48 is sufficiently smaller than the axial length of the outer covering rubber 34, and the annular stopper 48 is positioned sufficiently separated from the main rubber elastic body 16 in the axial direction. It has been.
[0041]
Then, the suspension bush 10 having such a structure is configured such that the inner cylinder fitting 12 is attached to the suspension arm 18 by the mounting rod 54 inserted through the inner cylinder fitting 12, as indicated by phantom lines in FIG. While fixedly attached by the mounting bolt 55, the outer cylinder fitting 14 is press-fitted and fixed in the mounting hole 56 formed in the suspension member 20, so that the suspension arm 18 is interposed at the mounting portion of the suspension member 20 with respect to the suspension member 20. 18 is connected to the suspension member 20 in a vibration-proof manner. In FIG. 1, annular plate-shaped buffer plates 53, 53 are mounted on the suspension arm 18 or the inner cylinder fitting 12 on both sides in the axial direction of the inner cylinder fitting 12. By being brought into contact with the contact members 57 and 58 fixed to the suspension member 20 through the buffer rubber plates 53 and 53, the stopper function in the axial direction is exhibited.
[0042]
Further, under such a mounted state, a vibration load in various directions such as an axial direction, a direction perpendicular to the axis, or a twisting direction is exerted between the inner and outer cylindrical fittings 12 and 14 of the suspension bush 10. When a large load is applied, the inner peripheral surface of the annular stopper 48 fitted and fixed to the outer cylinder fitting 14 is brought into contact with the inner cylinder fitting 12 via the inner covering rubber 32. As a result, the excessive deformation of the main rubber elastic body 16 and the excessive relative displacement of the inner and outer cylinder fittings 12 and 14 are limited in a buffering manner, and an effective stopper function is exhibited. As is clear from this, in the present embodiment, the inner covering rubber 32 Ring A cushioning rubber layer is configured to cushion the contact of the stopper 48 with the inner cylinder fitting 12. Further, even when a large load is input between the inner and outer cylinder fittings 12 and 14, the main rubber elastic body 16 and the annular stoppers 48 and 48 are prevented from interfering with the main rubber elastic body 16 by the annular stopper 48. A sufficient gap is formed between them.
[0043]
In particular, in the suspension bush 10 having the above-described structure, the annular stopper 48 is inserted into the fitting groove 36 formed in the outer covering rubber 34 when the annular stopper 48 is assembled to the integrally vulcanized molded product 22. Thus, the fitting concave groove 36 can be accurately set at a preset axial position, and such a set state can be easily confirmed from the outside in the axial direction by visual recognition or the like. Therefore, it is possible to stably set the annular stopper 48 with excellent workability, and the performance stability and reliability of the product are drastically improved. Therefore, the occurrence of defective products can be greatly reduced.
[0044]
The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention is not construed as being limited by the specific description in the embodiment. The present invention can be implemented in various modifications, corrections, and the like based on knowledge, and is not enumerated one by one, so long as such embodiments do not depart from the spirit of the present invention. Needless to say, it is included in the range.
[0045]
For example, as shown in FIG. 6, it is possible to tune the stopper function that is exhibited in different radial directions by changing the projecting height of the annular stopper 48 radially inward in the circumferential direction. It is.
[0046]
Further, as shown in FIG. 7, the outer cylinder member 60 made of a synthetic resin that is more easily deformed than a metal such as steel is employed, and the diameter of the suspension bush is reduced to a single unit with a special die or the like. Without being performed, the outer cylindrical member 60 is press-fitted into the mounting hole 56 to reduce the diameter of the outer cylindrical member 60 by a predetermined amount, whereby the annular stopper 48 is fitted to the outer cylindrical member 60 under the final mounting state. It is also possible to fix them. When the diameter of the outer cylinder member 60 is reduced and the annular stopper 48 is fixedly attached to the outer cylinder member 60 at the time of final mounting as described above, the annular stopper 48 is fitted to the fitting recess. The suspension bush is provided to the mounting process as a product in a state in which the final annular stopper 48 is not yet fitted and fixed by the diameter reduction of the outer cylindrical member 60 just by being inserted into the groove 36. Needless to say.
[0047]
Further, the elastic protrusions 46 on the bottom surface 38 of the fitting groove 36 are necessary in consideration of the height of the side wall surfaces 40, 42 on both sides in the axial direction of the fitting groove 36, the diameter reduction ratio with respect to the outer tubular metal fitting 14, and the like. It is adopted according to the above and is not essential to the present invention.
[0048]
Further, the annular stopper 48 is inserted into the fitting concave groove 36, and the annular stopper 48 is The The gap 50 formed between the outer peripheral surface of the topper 48 and the bottom surface 38 of the fitting groove 36 is also reduced in the diameter ratio with respect to the outer tube fitting 14 and the outer covering rubber 34 forming the bottom wall of the fitting groove 36. It is adopted as necessary in consideration of the thickness dimension and the like, and is not essential to the present invention.
[0049]
Furthermore, in the above embodiment, a pair of annular stoppers 48, 48 are assembled on both sides in the axial direction of the inner and outer cylindrical fittings 12, 14, but for example, in the vibration isolating bush described in JP-A-9-280314, etc. A mode in which the annular stopper member is assembled only on one side in the axial direction can be suitably employed.
[0050]
Further, in order to more effectively prevent the annular stopper 48 from coming out of the outer cylinder fitting 14 in the final state, for example, as shown in FIG. A caulking-like portion 60 that performs a locking action on the annular stopper 48 may be formed by increasing the amount.
[0051]
In addition, in the above-described embodiment, a specific example in which the present invention is applied to a suspension bush is shown. However, the present invention is not limited to various anti-vibration bushes including a cylindrical mount for automobiles, and various kinds other than automobiles. Needless to say, any of various types of vibration isolating bushes used in the apparatus can be applied.
[0052]
【The invention's effect】
As is clear from the above description, in the vibration-proof bushing having the structure according to the present invention, a fitting groove is formed in the holding rubber layer formed on the inner peripheral surface of the outer cylindrical member, and this Since the annular stopper member is inserted into the fitting concave groove and assembled, the annular stopper member can be easily assembled with respect to an accurate position, and the confirmation thereof is facilitated. Moreover, the position of the annular stopper member in the step before the diameter of the outer cylinder member is finally reduced and the annular stopper member is fitted and fixed to the outer cylinder fitting can be advantageously prevented. It can be fitted and fixed to the member with high positional accuracy, and the stability and reliability of the vibration-proof bushing performance is greatly increased without increasing the work load in the manufacturing process for confirmation and assembly. It can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional explanatory view showing a suspension bush as a first embodiment of the present invention.
FIG. 2 is a right side view of FIG.
3 is a longitudinal sectional view showing an integrally vulcanized molded product constituting the suspension bush shown in FIG. 1. FIG.
4 is an enlarged explanatory view of a main part of the integrally vulcanized molded product shown in FIG. 3. FIG.
5 is a longitudinal sectional view of an assembly for explaining one manufacturing process of the suspension bush shown in FIG. 1. FIG.
FIG. 6 is a right side view corresponding to FIG. 2 and showing another specific example of the present invention.
FIG. 7 is a longitudinal sectional explanatory view corresponding to FIG. 1, showing still another specific example of the present invention.
FIG. 8 is a longitudinal sectional view showing still another specific example of the present invention.
[Explanation of symbols]
10 Suspension bush
12 Inner tube bracket
14 Outer tube bracket
16 Body rubber elastic body
22 Integrated vulcanized molded product
28 Axial extension
30 Axial extension
32 Inner coating rubber
34 Outer coating rubber
36 Fitting groove
38 Bottom
40 Side wall surface (inner side in the axial direction)
42 Side wall surface (outside in the axial direction)
46 Elastic ridges
48 Annular stopper
50 gap
52 Assembly

Claims

The outer cylindrical member is spaced apart from the inner shaft member in the radial direction, and a main rubber elastic body is disposed between the radially opposing surfaces of the inner shaft member and the outer cylindrical member. In the anti-vibration bushing vulcanized and bonded to the outer peripheral surface of the inner shaft member and the inner peripheral surface of the outer cylinder member,
At least one end in the axial direction of the inner shaft member and the outer cylindrical member is formed with an axially extending portion that extends in the axial direction from the connecting portion by the main rubber elastic body and is opposed to each other in the radial direction. A holding rubber layer extending on the inner peripheral surface of the axially extending portion of the outer cylindrical member is formed integrally with the main rubber elastic body, and opens radially inwardly in the holding rubber layer. with fitting groove is formed extending, they are allowed disposed annular stopper member is placed inserted in the fitting groove, the annular stopper member is positioned in axial side walls of the fitting groove are held, vibration damping bushing, characterized in that said outer tubular member which holds the annular stopper member is reduced in diameter deformed annular stopper member is fitted and fixed to the outer cylindrical member.

The anti-vibration bush according to claim 1, wherein an elastic protrusion is formed on a bottom surface of the fitting concave groove, and an outer peripheral surface of the annular stopper member is partially in contact with the elastic protrusion.

The inner peripheral surface of the axially outer wall portion of the fitting groove formed by the holding rubber layer is a tapered surface that expands outward in the axial direction. Anti-vibration bush.

The said outer cylinder member is comprised with the metal outer cylinder metal fitting, and the said annular stopper member is engage | inserted and fixed with respect to this outer cylinder metal fitting by the diameter reduction of this outer cylinder metal fitting. The vibration-isolating bush according to any one of 3.

The anti-vibration bush according to any one of claims 1 to 4, wherein in the annular stopper member, a protruding height in a radial direction protruding from the outer cylinder member side toward the inner shaft member side is varied in a circumferential direction.

The outer cylinder member is spaced apart from the inner shaft member in the radial direction, and the main rubber elastic body is disposed between the radially opposing surfaces of the inner shaft member and the outer cylinder member so that the main rubber elastic body is disposed on the inner shaft member. When manufacturing anti-vibration bushes each vulcanized and bonded to the outer peripheral surface of the shaft member and the inner peripheral surface of the outer cylinder member,
At least one end in the axial direction of the inner shaft member and the outer cylinder member is formed with an axially extending portion that extends in the axial direction from the connecting portion by the main rubber elastic body and is opposed to each other in the radial direction. A holding rubber layer that extends on the inner peripheral surface of the axially extending portion of the outer cylinder member is formed integrally with the main rubber elastic body, and is opened radially inward in the holding rubber layer in the circumferential direction. In a state where an extending fitting groove is formed and an annular stopper member is inserted and arranged in the fitting groove, and the annular stopper member is positioned and held on both side walls in the axial direction of the fitting groove. The method of manufacturing a vibration isolating bushing according to claim 1, wherein the outer cylindrical member holding the annular stopper member is deformed in a reduced diameter, and the annular stopper member is fitted and fixed to the outer cylindrical member.