JP4046007B2

JP4046007B2 - Dynamic damper

Info

Publication number: JP4046007B2
Application number: JP2003146024A
Authority: JP
Inventors: 直仁桑山
Original assignee: Sumitomo Riko Co Ltd
Current assignee: Sumitomo Riko Co Ltd
Priority date: 2003-05-23
Filing date: 2003-05-23
Publication date: 2008-02-13
Anticipated expiration: 2023-05-23
Also published as: JP2004347052A

Description

【０００１】
【発明の属する技術分野】
本発明は、車両等のエンジン又はトランスミッション等に取り付けられるダイナミックダンパに係り、特に内筒金具とその外周側に同軸状に配置された質量金具側との間を振動入力方向に対して直交して径方向に延びて連結するゴム弾性体連結部の剪断変形により振動入力を減衰させるダイナミックダンパに関する。
【０００２】
【従来の技術】
従来、この種のダイナミックダンパは、例えば、図１０，図１１に示すように、内筒金具２と、内筒金具２の外周側に離間して同軸状に配設された外筒金具３と、内外筒金具２，３の対向面間にて振動入力方向（図示上下方向）に対して直交するように径方向に延設されて内外筒金具２，３間を弾性的に連結する厚板状の一対のゴム弾性体連結部４とを備えたゴムブッシュ１と、ゴムブッシュ１の外筒金具３の外周面に中心孔にて圧入によって挿嵌されることにより外筒金具３に固定された筒状の質量金具５とを備えている。このダイナミックダンパは、内筒金具２に加えられる振動入力をゴム弾性体連結部４の剪断変形によって減衰させるものである。同様の構造のダイナミックダンパとしては、例えば特許文献１に開示されている。
【０００３】
【特許文献１】
特開２０００−３３７４３１号公報（第２頁、図１−図４）
【０００４】
【発明が解決しようとする課題】
ところで、上記ダイナミックダンパは、振動入力の大きさによって、動バネ特性が変動する性質を備えている。図５に示すように、ゴム弾性体のたわみ（ｍｍ）を横軸に、ゴム弾性体に加えられる動荷重（Ｎ）を縦軸とすると、ゴム弾性体の振動の１周期ごとに図に示すように閉ループである動荷重−たわみ線図が描かれる。この動荷重−たわみ線図の傾きが動バネ特性を表している。振動入力が小さいすなわち小振幅のときは、ゴム弾性体の動荷重−たわみ線図Ａの傾斜が大きくなっており、その動バネ定数が大きいが、振動入力が大きいすなわち大振幅になると、動荷重−たわみ線図Ｂの傾斜が緩やかになり、その動バネ定数が小さくなる。このような振動入力による動バネ特性の変動が、動バネ特性の振幅依存性と言われている。
【０００５】
このように動バネ定数が変動することにより、ダイナミックダンパの共振周波数が変動し、その結果、ダイナミックダンパの振動減衰性能が低下するという問題がある。例えば、振動入力の大きさが１Ｇのときの共振周波数が１００Ｈｚのダイナミックダンパの場合、振動入力の大きさが３Ｇになると共振周波数が９２Ｈｚと大きく低下し、ダイナミックダンパの振動減衰性能が大きく損なわれる結果となる。特に、ダイナミックダンパが、エンジン、トランスミッション等のような加えられる振動入力の大きな部位に適用される場合に、このような共振周波数の変動が問題となる。
【０００６】
本発明は上記した問題を解決しようとするもので、車両等から加えられる振動入力の変動に対して、ゴム弾性体連結部の動バネ定数の変動を抑えることにより、共振周波数の変動を小さくして振動減衰性能を適正に発揮できるダイナミックダンパを提供することを目的とする。
【０００７】
【課題を解決するための手段】
上記目的を達成するために、上記請求項１に記載の発明の構成上の特徴は、内筒金具と、内筒金具の外周側に離間して同軸状に配置された外筒金具と、内筒金具と外筒金具の対向面間にて振動入力方向に対して直交するように径方向に延設されて内筒金具及び外筒金具間を弾性的に連結し内筒金具に加えられる振動入力を受けて剪断変形する一対のゴム弾性体連結部と、内筒金具及び一対のゴム弾性体連結部を挟んだ振動入力方向の両側にて軸方向に貫通した一対の空間部とを設けたゴムブッシュと、ゴムブッシュの外筒金具の外周面に圧入によって挿嵌されることにより外筒金具に固定された筒状の質量金具とを備えたダイナミックダンパであって、振動入力方向に面した内筒金具の外周面及び外筒金具の内周面の内のいずれか一方に接着されて、空間部内を内筒金具の外周面及び外筒金具の内周面の他方に向けて突出し、突出した先端が他方の面に非接着で当接した一対のゴム弾性体突出部を設け、ゴム弾性体突出部は山形で先端側が断面略三角形に突出したものであり、ゴム弾性体突出部が振動入力に応じて圧縮変形することにより振動入力の変動によるゴム弾性体連結部の動バネ定数の変動を補償するものであり、大振幅時の動バネ特性が小振幅時の動バネ特性に近似したものになることにある。
【０００８】
上記のように構成した請求項１の発明においては、ゴム弾性体連結部が内筒金具に加えられる振動入力を受けて剪断変形するのに対して、振動入力方向に面した内筒金具の外周面及び外筒金具の内周面のいずれか一方に固定されて他方に向けて突出したゴム弾性体突出部の先端が、他方の面に非接着で当接しているため、振動入力に応じて圧縮変形するようになっている。そのため、内筒金具に加えられる振動入力が大きくなるにしたがって、振動入力に対して直交方向に延びたゴム弾性体連結部の動バネ定数が小さくなるが、ゴム弾性体突出部の圧縮変形によって、ゴム弾性体連結部の動バネ定数の変動を抑制すなわち補償することができる。
【０００９】
具体的には、大振幅の振動入力に対しては、ゴム弾性体突出部が圧縮変形することにより、図５に示すように、ゴム弾性体全体のたわみと振動の動荷重との関係を表す動荷重−たわみ線図Ｃが、両端側で動荷重が大きくなるように折れ曲り、すなわち従来の線形形状の線図Ｂから小振幅時の線図Ａ側に曲げられた非線形形状に変形される。そのため、大振幅の振動入力時の動荷重−たわみ線図Ｃの傾斜が、小振幅時の線図Ａの傾斜に近似したものにされ、大振幅時の動バネ特性が小振幅時の特性に近似したものになる。その結果、請求項１の発明においては、振動入力が大きくなっても、ゴム弾性体連結部の動バネ定数の変動が抑えられることにより、ダイナミックダンパの共振周波数の変動が抑えられる。
【００１０】
また、ゴム弾性体突出部の先端側が断面略三角形に突出していることにより、振動入力が大きくなるにしたがって、その圧縮変形の程度が徐々に大きくなる。そのため、ゴム弾性体突出部による、ゴム弾性体連結部の動バネ定数の変動を補償する効果が適正に発揮される。
【００１１】
また、上記請求項２に記載の発明の構成上の特徴は、内筒金具と、内筒金具の外周側に離間して同軸状に配置された外筒金具と、内筒金具と外筒金具の対向面間にて振動入力方向に対して直交するように径方向に延設されて内筒金具及び外筒金具間を弾性的に連結し内筒金具に加えられる振動入力を受けて剪断変形する一対のゴム弾性体連結部と、内筒金具及び一対のゴム弾性体連結部を挟んだ振動入力方向の両側にて軸方向に貫通した一対の空間部とを設けたゴムブッシュと、ゴムブッシュの外筒金具の外周面に圧入によって挿嵌されることにより外筒金具に固定された筒状の質量金具とを備えたダイナミックダンパであって、振動入力方向に面した内筒金具の外周面及び外筒金具の内周面の内のいずれか一方に接着されて、空間部内を内筒金具の外周面及び外筒金具の内周面の他方に向けて突出し、突出した先端が他方の面に非接着で当接した一対のゴム弾性体突出部を設け、ゴム弾性体突出部は先端側が部分的に突出した小突起部となっており、ゴム弾性体突出部が振動入力に応じて圧縮変形することにより振動入力の変動によるゴム弾性体連結部の動バネ定数の変動を補償するものであり、大振幅時の動バネ特性が小振幅時の動バネ特性に近似したものになることにある。
【００１２】
上記のように構成した請求項２の発明においては、上記発明の作用効果に加えて、ゴム弾性体突出部の先端側が部分的に突出した小突起部となっていることにより、振動入力が大きくなるにしたがって、その圧縮変形の程度が徐々に大きくなるため、ゴム弾性体突出部による、ゴム弾性体連結部の動バネ定数の変動を補償する効果が適正に発揮される。
【００１３】
【発明の実施の形態】
以下、本発明の実施形態について図面を用いて説明する。図１，図２は、同実施形態である自動車のトランスミッションに固定される取付部材に取り付けられるダイナミックダンパを軸方向断面図及び一部破断側面図により示したものである。図３，図４は、同ダイナミックダンパを構成するゴムブッシュを軸方向断面図及び一部破断側面図により示したものである。
【００１４】
ダイナミックダンパは、内筒金具１１と、内筒金具１１の外方に同軸状に配設された外筒金具１３と、内外筒金具１１，１３の対向面間にて図示上下方向である振動入力方向に対して直交するように水平に径方向に延設されて内外筒金具１１，１３に接着されて両者間を弾性的に連結する一対のゴム弾性体連結部１５と、内筒金具１１及びゴム弾性体連結部１５を挟んだ振動入力方向両側にて軸方向に貫通した一対の空間部１９と、ゴム弾性体連結部１５と直交する内筒金具１１の外周面に固定されて外筒金具の内周面に向けて空間部１９内に突出し、突出した先端が外筒金具１３の内周面に非接着で当接した一対のゴム弾性体突出部１７とを有するゴムブッシュ１０を有しており、外筒金具１３の外周面に円筒状の質量金具２１が圧入により挿嵌されている。このダイナミックダンパは、内筒金具１１に加えられる振動入力に対して、質量金具２１の振動に伴うゴム弾性体連結部１５及びゴム弾性体突出部１７の弾性変形による共振作用によって減衰させるもので、共振周波数として１００〜３００Ｈｚの周波数域に適用される。なお、ダイナミックダンパの振動入力方向については、図の上下方向に対応するものとする。
【００１５】
内筒金具１１は、金属製の真直な厚肉パイプであり、その軸孔１２の両端側の内周面が全周にわたって切り欠かれて軸方向外方に向けて拡径状態で傾斜した環状の傾斜部１２ａにされている。傾斜部１２ａを設けたことにより、棒状部材の内筒金具１１へのスムーズな挿嵌が可能になる。外筒金具１３は、金属製の真直な薄肉パイプであり、軸方向長さが内筒金具１１よりわずかに短く、外径が内筒金具１１の外径の略２倍程度になっている。また、外筒金具１３は、両端側の外周面が全周にわたって切り欠かれて軸方向外方に向けて縮径状態で傾斜した環状の傾斜部１３ａにされている。傾斜部１３ａを設けたことにより、外筒金具１３の質量金具２１へのスムーズな挿嵌が可能になる。外筒金具１３は、内筒金具１１の外周側に離間して同軸状にかつ内筒金具１１の軸方向両端間にて軸方向に対称に配置されている。
【００１６】
ゴム弾性体連結部１５は、内外筒金具１１，１３の対向面間の空間部分を略水平に径方向に延びた厚肉のゴム弾性体であって、その厚さは内筒金具１１の外径と略同一になっている。ゴム弾性体連結部１５は、外筒金具１３との接着部分において、厚肉部分の周方向両端側から周方向に厚肉部分も含めた中心角が略９０°になるように広がった薄肉部１６になっている。また、ゴム弾性体連結部１５は、軸方向両端面が軸方向内方にわずかに湾曲して凹んでいる。一対のゴム弾性体連結部１５によって、内外筒金具１１，１３間の円筒形空間が、内筒金具１１及びゴム弾性体連結部１５を挟んだ軸方向に貫通した一対の空間部１９に仕切られている。
【００１７】
ゴム弾性体突出部１７は、ゴム弾性体連結部１５と直交する内筒金具１１の径方向の両外周面から空間部１９内に振動入力方向に延びている。ゴム弾性体突出部１７は、図３及び図４に示すように、軸方向断面が底角の小さい偏平な等脚台形形状に突出しており、外筒金具近傍位置でさらに底角が小さくなるように折り曲げられて傾斜した偏平な二等辺三角形状になっていると共に、軸直角方向断面が底角の大きな等脚台形形状に突出しており、外筒金具近傍位置で底角がわずかに小さくなるように折り曲げられて傾斜した二等辺三角形になっている。すなわち、ゴム弾性体突出部１７は、内筒金具１１側の軸方向に長い四角錐台形の基部１８ａと、基部１８ａに積み重ねられた外筒金具１３側の偏平な四角錐形の先端部１８ｂとにより構成されている。なお、ゴム弾性体突出部１７の形状については、これに限らず、単一の四角錐形状であってもよく、さらに先端が突出した類似の形状であってもよい。
【００１８】
ゴム弾性体連結部１５及びゴム弾性体突出部１７は、内筒金具１１及び外筒金具１３にゴム加硫成形により一体で接着形成されるもので、両金具１１，１３と共に一体加硫成形品であるゴムブッシュ１０を構成している。ゴム加硫成形直後のゴムブッシュ１０は、図３及び図４に示すように、ゴム弾性体突出部１７の先端部１８ｂの頂部と外筒金具１３内周面との間に隙間Ｇを設けた状態になっている。ゴム加硫成形直後のゴムブッシュ１０は、通常は加硫成形後のゴム弾性体の引張歪を除去するために外筒金具１３に対して八方絞り等の縮径加工が施される。
【００１９】
質量金具２１は、厚肉の円筒形の金具であり、その内径が外筒金具１３の外径よりわずかに小さく、かつ軸方向長さが外筒金具１３の軸方向長さと同等ないしわずかに大きくされている。質量金具２１は、中心孔２２の軸方向両端側が全周にわたって切り欠かれて軸方向外方に向けて拡径状態で傾斜した環状の傾斜部２２ａにされており、外筒金具１３の質量金具２１へのスムーズな挿嵌が可能にされている。
【００２０】
質量金具２１の中心孔２２に、上記縮径加工の施されたゴムブッシュ１０が外筒金具１３にて圧入によって挿嵌されることにより、外筒金具１３がさらに縮径して、質量金具２１は外筒金具１３の外周面に圧着状態で強固に固定されて、ダイナミックダンパが得られる。このように、外筒金具１３が縮径することにより、ゴム弾性体突出部１７の先端部１８ｂの頂部と外筒金具１３内周面との間の隙間Ｇが無くされて、両者が非接着で当接した状態となる。また、外筒金具１３が質量金具２１に圧入されて一体となることにより、外筒金具１３も質量金具の一部として機能することになる。なお、縮径加工が施されさらに質量金具２１に圧入されて外筒金具１３が縮径することにより、ゴム弾性体連結部１５が径方向に圧縮されるため、その加硫成形後の収縮による引張歪が除去され、ゴム弾性体が安定状態に維持される。
【００２１】
このダイナミックダンパは、ゴム弾性体突出部１７を振動入力方向である図示上下方向に向けた状態で、車両のトランスミッションに設けた図示しない取付部材の外周側に、内筒金具１１の軸孔１２にて圧入によって挿嵌されることにより、取付部材に強固に固定される。
【００２２】
上記実施形態においては、ゴム弾性体連結部１５と直交して振動入力方向を向いたゴム弾性体突出部１７の突出端部である先端部１８ｂの頂部が、外筒金具１３の内周面に非接着で当接した状態になっている。そのため、ゴム弾性体連結部１５が内筒金具１１に加えられる振動入力を受けて剪断変形するのに対して、ゴム弾性体突出部１７は、内筒金具１１に加えられる振動入力を受けて先端部１８ｂ側が徐々に圧縮変形する。そのため、内筒金具１１に加えられる振動入力が大きくなるにしたがって、振動入力に対して直交方向に延びたゴム弾性体連結部１５の動バネ定数が小さくなるが、ゴム弾性体突出部１７の圧縮変形の程度が大きくなる。その結果、図５に示すように、ゴム弾性体全体の動荷重−たわみ線図Ｃが、両端側で動荷重が大きくなるように折れ曲り、すなわち従来の線形形状の線図Ｂから小振幅時の線図Ａ側に曲げられた非線形形状に変形される。これにより、大振幅の振動入力時の動荷重−たわみ線図Ｃの傾斜が、小振幅時の線図Ａの傾斜に近似したものにされ、大振幅時の動バネ特性が小振幅時の動バネ特性に近似したものになる。
【００２３】
これにより、ゴム弾性体突出部１７がゴム弾性体連結部１５の動バネ定数の変動を補償し、ゴム弾性体全体としての動バネ定数の変動を抑えることができる。その結果、本実施形態においては、振動入力が大きくなっても、ダイナミックダンパの共振周波数の変動が抑えられ、その振動減衰性能が適正に発揮される。例えば、振動入力の大きさが１Ｇのときの共振周波数が１００Ｈｚのダイナミックダンパの場合、振動入力の大きさが３Ｇに増大しても、その共振周波数は９６Ｈｚとなり、従来例の９２Ｈｚに比べてその低下の程度が大幅に抑えられる。そのため、本実施形態のダイナミックダンパは、エンジン、トランスミッション等のような加えられる振動入力の大きな部位に好適に使用される。
【００２４】
なお、上記実施形態の変形例として、図６，図７に示すように、ゴム弾性体突出部２３を、軸方向に長い外筒金具１３内周面近傍まで突出した四角錐台形の基部２４に、その先端面の中央から部分的に突出した小突起部２５を設けた構成とすることができる。このように、ゴム弾性体突出部２３の先端側が小突起部２５となっていることにより、振動入力が大きくなるにしたがって、圧縮変形の程度が徐々に大きくなる。そのため、第１実施形態と同様に、ゴム弾性体連結部１５の動バネ定数の変動を適正に補償することができる。
【００２５】
つぎに、第２実施形態について説明する。
本実施形態においては、上記第１実施形態及び変形例に示したようにゴム弾性体突出部１７，２３を内筒金具１１外周面に設けて、その先端部を外筒金具１３の内周面に当接させる代りに、図８，図９に示すように、略四角錐形状の一対のゴム弾性体突出部２７を、振動入力方向における外筒金具１３の両内周面に接着して空間部１９内に突出させ、突出した先端を内筒金具１１の両外周面にてゴム弾性体連結部１５から延出した薄肉のゴム被覆部１５ａに非接着で当接させるようにしたものである。このように構成した第２実施形態においても、上記第１実施形態と同様に、振動入力が大きくなっても、ゴム弾性体突出部２７によってゴム弾性体連結部１５の動バネ定数の変動を適正に補償することができる。その結果、第２実施形態においても、ダイナミックダンパの共振周波数の変動を抑え、ダイナミックダンパの振動減衰性能を適正に発揮させることができる。なお、ゴム弾性体突出部の形状については、上記変形例に示したように、四角錐台部の先端面に小突起部を設けた形状としてもよい。
【００２６】
なお、本発明のダイナミックダンパは、車両に限らず、他の同様な用途に使用可能である。その他、上記実施形態に示したダイナミックダンパについては、一例であり、本発明の要旨を逸脱しない範囲において、種々の形態で実施することができる。
【００２７】
【発明の効果】
上記請求項１，２の発明によれば、ゴム弾性体連結部と直交する内筒金具の外周面及び外筒金具の内周面のいずれか一方の面に接着固定されたゴム弾性体突出部を設けて、その突出端を他方の面に非接着で当接させたことにより、ゴム弾性体突出部がゴム弾性体連結部の動バネ定数の変動を補償することができ、その結果、ダイナミックダンパの共振周波数の変動が抑えられ、その振動減衰性能が適正に発揮される。
【００２８】
また、ゴム弾性体突出部の先端側形状は、断面略三角形に突出させたり、部分的に突出した小突起部とすることにより、ゴム弾性体連結部の動バネ定数の変動を是正する効果が確実に得られる。
【図面の簡単な説明】
【図１】本発明の第１実施形態であるダイナミックダンパを示す図２のＩ−Ｉ線方向の断面図である。
【図２】同ダイナミックダンパを示す右半分が軸方向中間位置にて破断された一部破断側面図である。
【図３】同ダイナミックダンパのゴムブッシュを示す図４のＩＩＩ−ＩＩＩ線方向の断面図である。
【図４】同ゴムブッシュを示す右半分が軸方向中間位置にて破断された一部破断側面図である。
【図５】ダイナミックダンパの振動入力によるゴム弾性体のたわみと動荷重との関係を概略的に示すグラフである。
【図６】変形例であるダイナミックダンパを示す図６のＶ−Ｖ線方向の断面図である。
【図７】同ダイナミックダンパを示す右半分が軸方向中間位置にて破断された一部破断側面図である。
【図８】第２実施形態であるダイナミックダンパを示す図９のＶＩＩＩ−ＶＩＩＩ線方向の断面図である。
【図９】同ダイナミックダンパを示す右半分が軸方向中間位置にて破断された一部破断側面図である。
【図１０】従来例であるダイナミックダンパを示す図１１のＸ−Ｘ線方向の断面図である。
【図１１】同ダイナミックダンパを示す右半分が軸方向中間位置にて破断された一部破断側面図である。
【符号の説明】
１０…ゴムブッシュ、１１…内筒金具、１３…外筒金具、１５…ゴム弾性体連結部、１７，２３，２７…ゴム弾性体突出部、１８ｂ…先端部、２１…質量金具、２５…小突起部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dynamic damper attached to an engine or a transmission of a vehicle or the like, and in particular, between an inner cylindrical metal fitting and a mass metal fitting arranged coaxially on the outer peripheral side thereof, orthogonal to the vibration input direction. The present invention relates to a dynamic damper that attenuates vibration input by shear deformation of a rubber elastic body connecting portion that extends in the radial direction and is connected.
[0002]
[Prior art]
Conventionally, this type of dynamic damper includes, for example, as shown in FIGS. 10 and 11, an inner cylinder fitting 2, and an outer cylinder fitting 3 that is coaxially disposed apart from the outer peripheral side of the inner cylinder fitting 2. A thick plate that extends radially between the opposing surfaces of the inner and outer cylinder fittings 2 and 3 so as to be orthogonal to the vibration input direction (the vertical direction in the figure) and elastically connects the inner and outer cylinder fittings 2 and 3 A rubber bush 1 having a pair of rubber elastic body connecting portions 4 and an outer peripheral surface of the outer tube fitting 3 of the rubber bush 1 are fixed to the outer tube fitting 3 by being press-fitted in the center hole. And a cylindrical mass metal fitting 5. The dynamic damper attenuates the vibration input applied to the inner cylindrical metal fitting 2 by the shear deformation of the rubber elastic body connecting portion 4. A dynamic damper having a similar structure is disclosed in Patent Document 1, for example.
[0003]
[Patent Document 1]
JP 2000-337431 A (2nd page, FIGS. 1 to 4)
[0004]
[Problems to be solved by the invention]
By the way, the dynamic damper has a property that the dynamic spring characteristic varies depending on the magnitude of the vibration input. As shown in FIG. 5, when the deflection (mm) of the rubber elastic body is taken on the horizontal axis and the dynamic load (N) applied to the rubber elastic body is taken on the vertical axis, the vibration elastic body is shown in the figure for each period of vibration. Thus, a dynamic load-deflection diagram which is a closed loop is drawn. The inclination of the dynamic load-deflection diagram represents the dynamic spring characteristic. When the vibration input is small, that is, a small amplitude, the slope of the dynamic load-deflection diagram A of the rubber elastic body is large and the dynamic spring constant is large, but when the vibration input is large, that is, a large amplitude, the dynamic load is large. -The inclination of the deflection diagram B becomes gentle and the dynamic spring constant becomes small. Such fluctuation of the dynamic spring characteristics due to vibration input is said to be amplitude dependency of the dynamic spring characteristics.
[0005]
As the dynamic spring constant fluctuates in this way, the resonance frequency of the dynamic damper fluctuates, and as a result, there is a problem that the vibration damping performance of the dynamic damper decreases. For example, in the case of a dynamic damper with a resonance frequency of 100 Hz when the magnitude of the vibration input is 1 G, the resonance frequency is greatly reduced to 92 Hz when the magnitude of the vibration input is 3 G, and the vibration damping performance of the dynamic damper is greatly impaired. Result. In particular, when the dynamic damper is applied to a portion where a large vibration input is applied, such as an engine, a transmission, or the like, such a fluctuation in resonance frequency becomes a problem.
[0006]
The present invention is intended to solve the above-described problem. By suppressing the fluctuation of the dynamic spring constant of the rubber elastic body connecting portion against the fluctuation of the vibration input applied from a vehicle or the like, the fluctuation of the resonance frequency is reduced. It is an object of the present invention to provide a dynamic damper that can properly exhibit vibration damping performance.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the structural features of the invention described in claim 1 include an inner cylinder fitting, an outer cylinder fitting arranged coaxially and spaced from the outer peripheral side of the inner cylinder fitting, Vibration applied to the inner cylinder fitting by elastically connecting the inner cylinder fitting and the outer cylinder fitting between the opposing surfaces of the cylinder fitting and the outer cylinder fitting so as to be orthogonal to the vibration input direction. Provided with a pair of rubber elastic body connecting portions that receive input and undergo shear deformation, and a pair of space portions that penetrate in the axial direction on both sides of the vibration input direction across the inner cylinder fitting and the pair of rubber elastic body connecting portions A dynamic damper having a rubber bush and a cylindrical mass metal fitting fixed to the outer cylindrical metal fitting by being press-fitted into the outer peripheral surface of the outer cylindrical metal fitting of the rubber bush, facing the vibration input direction Bonded to either the outer peripheral surface of the inner tube bracket or the inner periphery of the outer tube bracket A pair of rubber elastic body protrusions protruding in the space toward the other of the outer peripheral surface of the inner cylindrical fitting and the inner peripheral surface of the outer cylindrical fitting, and the protruding tip non-adhering to the other surface. The rubber elastic body protrusion has a mountain shape and the front end protrudes in a substantially triangular cross section, and the rubber elastic body protrusion is compressed and deformed in response to vibration input, so that the dynamic spring of the rubber elastic body connecting portion due to fluctuations in vibration input This is to compensate for fluctuations in the constant , and the dynamic spring characteristic at the time of large amplitude is approximated to the dynamic spring characteristic at the time of small amplitude .
[0008]
In the invention of claim 1 configured as described above, the rubber elastic body connecting portion undergoes shearing deformation upon receiving vibration input applied to the inner cylinder fitting, whereas the outer periphery of the inner cylinder fitting facing the vibration input direction. The tip of the rubber elastic body protrusion that is fixed to one of the surface and the inner peripheral surface of the outer tube metal fitting and protrudes toward the other is in non-adhesive contact with the other surface, so that it can respond to vibration input. It is designed to be compressed and deformed. Therefore, as the vibration input applied to the inner cylinder fitting increases, the dynamic spring constant of the rubber elastic body connecting portion extending in the direction orthogonal to the vibration input decreases, but due to the compression deformation of the rubber elastic body protruding portion, The fluctuation of the dynamic spring constant of the rubber elastic body connecting portion can be suppressed, that is, compensated.
[0009]
Specifically, for a large amplitude vibration input, the rubber elastic body protrusion is compressed and deformed to represent the relationship between the deflection of the entire rubber elastic body and the dynamic load of vibration, as shown in FIG. The dynamic load-deflection diagram C is bent so that the dynamic load increases at both ends, that is, the conventional linear diagram B is deformed into a non-linear shape bent to the diagram A side at a small amplitude. . For this reason, the inclination of the dynamic load-deflection diagram C at the time of large amplitude vibration input is approximated to the inclination of the diagram A at the time of small amplitude, and the dynamic spring characteristic at the time of large amplitude becomes the characteristic at the time of small amplitude. Approximate. As a result, in the first aspect of the present invention, even if the vibration input is increased, the fluctuation of the dynamic spring constant of the rubber elastic body connecting portion is suppressed, whereby the fluctuation of the resonance frequency of the dynamic damper is suppressed.
[0010]
Further, since the tip end side of the rubber elastic body protruding portion protrudes in a substantially triangular cross section, the degree of the compressive deformation gradually increases as the vibration input increases. Therefore, the effect which compensates the fluctuation | variation of the dynamic spring constant of a rubber elastic body connection part by a rubber elastic body protrusion part is exhibited appropriately.
[0011]
Further, the structural features of the invention described in claim 2 are that the inner cylinder fitting, the outer cylinder fitting arranged coaxially and spaced apart from the outer peripheral side of the inner cylinder fitting, the inner cylinder fitting and the outer cylinder fitting Between the opposing surfaces of the inner cylindrical bracket and the outer cylindrical bracket, which are extended in the radial direction so as to be orthogonal to the vibration input direction, and are sheared by receiving vibration input applied to the inner cylindrical bracket. A rubber bush provided with a pair of rubber elastic body connecting portions, and a pair of space portions penetrating in the axial direction on both sides of the vibration input direction sandwiching the inner cylinder fitting and the pair of rubber elastic body connecting portions, and a rubber bush A dynamic damper having a cylindrical mass fitting fixed to the outer cylinder fitting by being press-fitted into the outer circumference of the outer cylinder fitting, and the outer circumference of the inner cylinder fitting facing the vibration input direction And the inner surface of the outer tube fitting are bonded to one of the inner peripheral surfaces to Protrudes toward the other of the inner peripheral surface of the outer peripheral surface and the outer sleeve of the fitting, a pair of rubber elastic body protruding portion in contact with a non-adhesive protruding tip on the other surface is provided, the rubber elastic body protrusion tip side has a small projection portion partially protruding, which rubber elastic body protruding portion to compensate for variations in the dynamic spring constant of the rubber elastic body connecting part due to variations in the vibration input by compressive deformation in accordance with the vibration input Therefore, the dynamic spring characteristic at the time of large amplitude is approximated to the dynamic spring characteristic at the time of small amplitude .
[0012]
In the invention of claim 2 configured as described above, in addition to the function and effect of the invention described above, the tip of the rubber elastic body protruding portion is a small protruding portion that partially protrudes, so that the vibration input is large. As the degree of compressive deformation gradually increases, the effect of compensating the fluctuation of the dynamic spring constant of the rubber elastic body connecting portion by the rubber elastic body protruding portion is appropriately exhibited .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a dynamic damper attached to an attachment member fixed to a transmission of an automobile according to the embodiment in an axial sectional view and a partially broken side view. 3 and 4 show a rubber bush constituting the dynamic damper in an axial sectional view and a partially broken side view.
[0014]
The dynamic damper includes an inner cylindrical metal fitting 11, an outer cylindrical metal fitting 13 disposed coaxially on the outer side of the inner cylindrical metal fitting 11, and a vibration input in the vertical direction shown in the figure between the opposing surfaces of the inner and outer cylindrical metal fittings 11 and 13. A pair of rubber elastic body connecting portions 15 that extend horizontally in the radial direction so as to be orthogonal to the direction and are bonded to the inner and outer cylinder fittings 11 and 13 to elastically connect the two, the inner cylinder fitting 11 and A pair of space portions 19 penetrating in the axial direction on both sides of the vibration input direction across the rubber elastic body connecting portion 15 and an outer cylinder metal fitting fixed to the outer peripheral surface of the inner cylinder metal fitting 11 orthogonal to the rubber elastic body connecting portion 15 A rubber bushing 10 having a pair of rubber elastic body projecting portions 17 projecting into the space portion 19 toward the inner peripheral surface of the outer cylindrical metal fitting and a protruding tip abutting against the inner peripheral surface of the outer tube fitting 13 in a non-adhesive manner. A cylindrical mass 21 is press-fitted on the outer peripheral surface of the outer cylinder 13. It has been inserted. This dynamic damper attenuates the vibration input applied to the inner cylindrical metal fitting 11 by the resonance action caused by the elastic deformation of the rubber elastic body connecting portion 15 and the rubber elastic body protruding portion 17 accompanying the vibration of the mass metal fitting 21. The resonance frequency is applied to a frequency range of 100 to 300 Hz. Note that the vibration input direction of the dynamic damper corresponds to the vertical direction in the figure.
[0015]
The inner cylinder 11 is a straight, thick metal pipe, and the inner peripheral surface of both end sides of the shaft hole 12 is notched over the entire circumference, and is an annular shape that is inclined in a diameter-expanded state outward in the axial direction. The inclined portion 12a. By providing the inclined portion 12a, it is possible to smoothly insert the rod-like member into the inner cylindrical metal fitting 11. The outer cylinder fitting 13 is a straight metal thin pipe, has an axial length slightly shorter than the inner cylinder fitting 11, and has an outer diameter that is approximately twice the outer diameter of the inner cylinder fitting 11. Further, the outer cylinder fitting 13 is formed into an annular inclined portion 13a in which the outer peripheral surfaces on both end sides are notched over the entire circumference and inclined in a reduced diameter state in the axially outward direction. By providing the inclined portion 13a, the outer tubular fitting 13 can be smoothly inserted into the mass fitting 21. The outer cylinder fitting 13 is spaced apart on the outer peripheral side of the inner cylinder fitting 11 and is coaxially arranged symmetrically in the axial direction between both axial ends of the inner cylinder fitting 11.
[0016]
The rubber elastic body connecting portion 15 is a thick rubber elastic body that extends in the radial direction substantially horizontally in the space between the opposing surfaces of the inner and outer cylindrical fittings 11, 13. It is almost the same as the diameter. The rubber elastic body connecting portion 15 is a thin-walled portion that is widened so that the central angle including the thick-walled portion is approximately 90 ° in the circumferential direction from the both ends in the circumferential direction of the thick-walled portion at the bonding portion with the outer cylinder fitting 13. It is 16. Further, the rubber elastic body connecting portion 15 has both end surfaces in the axial direction curved and recessed slightly inward in the axial direction. The pair of rubber elastic body connecting portions 15 divides the cylindrical space between the inner and outer cylinder fittings 11 and 13 into a pair of space portions 19 penetrating in the axial direction with the inner cylinder fitting 11 and the rubber elastic body connecting portion 15 interposed therebetween. ing.
[0017]
The rubber elastic body projecting portion 17 extends in the vibration input direction into the space portion 19 from both outer peripheral surfaces in the radial direction of the inner cylindrical metal member 11 orthogonal to the rubber elastic body connecting portion 15. As shown in FIGS. 3 and 4, the rubber elastic body projecting portion 17 projects into a flat isosceles trapezoidal shape with a small cross section in the axial direction so that the base angle is further reduced in the vicinity of the outer cylinder fitting. It is a flat isosceles triangle that is bent and slanted, and the cross section perpendicular to the axis protrudes into an isosceles trapezoid with a large base angle, so that the base angle is slightly smaller in the vicinity of the outer tube bracket. It is an isosceles triangle that is bent and inclined. That is, the rubber elastic body projecting portion 17 includes a rectangular pyramid-shaped base portion 18a that is long in the axial direction on the inner cylinder fitting 11 side, and a flat square pyramid tip portion 18b on the outer cylinder fitting 13 side that is stacked on the base portion 18a. It is comprised by. In addition, about the shape of the rubber elastic body protrusion part 17, not only this but a single square pyramid shape may be sufficient, and the similar shape which the front-end | tip protruded may be sufficient.
[0018]
The rubber elastic body connecting portion 15 and the rubber elastic body protruding portion 17 are integrally bonded to the inner cylinder fitting 11 and the outer cylinder fitting 13 by rubber vulcanization molding. The rubber bush 10 is configured. As shown in FIGS. 3 and 4, the rubber bush 10 immediately after the rubber vulcanization molding is provided with a gap G between the top of the tip 18 b of the rubber elastic body protrusion 17 and the inner peripheral surface of the outer cylinder fitting 13. It is in a state. The rubber bush 10 immediately after rubber vulcanization molding is usually subjected to diameter reduction processing such as eight-way drawing on the outer cylinder fitting 13 in order to remove the tensile strain of the rubber elastic body after vulcanization molding.
[0019]
The mass metal fitting 21 is a thick cylindrical metal fitting whose inner diameter is slightly smaller than the outer diameter of the outer cylinder fitting 13 and whose axial length is equal to or slightly larger than the axial length of the outer cylinder fitting 13. Has been. The mass metal fitting 21 is formed as an annular inclined portion 22a in which both ends in the axial direction of the center hole 22 are cut out over the entire circumference and inclined in the diameter-expanded state outward in the axial direction. Smooth insertion into 21 is made possible.
[0020]
When the rubber bush 10 subjected to the diameter reduction process is inserted into the center hole 22 of the mass metal fitting 21 by press fitting with the outer cylinder metal fitting 13, the outer cylinder metal fitting 13 is further reduced in diameter, and the mass metal fitting 21. Is firmly fixed to the outer peripheral surface of the outer tube fitting 13 in a crimped state, and a dynamic damper is obtained. Thus, by reducing the diameter of the outer cylinder fitting 13, the gap G between the top of the tip 18b of the rubber elastic body projecting portion 17 and the inner peripheral surface of the outer cylinder fitting 13 is eliminated, and both are not bonded. It will be in the state contacted by. Further, when the outer cylinder fitting 13 is press-fitted into the mass fitting 21 and integrated, the outer cylinder fitting 13 also functions as a part of the mass fitting. In addition, since the rubber elastic body connecting portion 15 is compressed in the radial direction when the diameter reduction processing is performed and the outer cylinder fitting 13 is pressed into the mass fitting 21 to reduce the diameter, the shrinkage after the vulcanization molding is performed. The tensile strain is removed, and the rubber elastic body is maintained in a stable state.
[0021]
This dynamic damper is formed in the shaft hole 12 of the inner cylindrical metal fitting 11 on the outer peripheral side of a mounting member (not shown) provided in the transmission of the vehicle with the rubber elastic body projecting portion 17 facing the vertical direction in the figure, which is the vibration input direction. By being inserted by press fitting, it is firmly fixed to the mounting member.
[0022]
In the above embodiment, the top of the tip 18b, which is the projecting end of the rubber elastic body projecting portion 17 orthogonal to the rubber elastic body connecting portion 15 and facing the vibration input direction, is on the inner peripheral surface of the outer cylinder fitting 13. It is in a non-adhesive contact state. Therefore, the rubber elastic body connecting portion 15 receives the vibration input applied to the inner cylindrical metal fitting 11 and undergoes shear deformation, whereas the rubber elastic body protrusion 17 receives the vibration input applied to the inner cylindrical metal fitting 11 and has a tip. The portion 18b side is gradually compressed and deformed. For this reason, as the vibration input applied to the inner cylindrical metal fitting 11 increases, the dynamic spring constant of the rubber elastic body connecting portion 15 extending in the direction orthogonal to the vibration input decreases, but the compression of the rubber elastic body protruding portion 17 decreases. The degree of deformation increases. As a result, as shown in FIG. 5, the dynamic load-deflection diagram C of the entire rubber elastic body is bent so that the dynamic load increases at both ends, that is, from the conventional linear diagram B, when the amplitude is small. Is deformed into a non-linear shape bent toward the diagram A side. As a result, the slope of the dynamic load-deflection diagram C at the time of large amplitude vibration input is approximated to the slope of the diagram A at the time of small amplitude, and the dynamic spring characteristic at the time of large amplitude is the motion at the time of small amplitude. It approximates the spring characteristics.
[0023]
Thereby, the rubber elastic body protrusion part 17 can compensate the fluctuation | variation of the dynamic spring constant of the rubber elastic body connection part 15, and can suppress the fluctuation | variation of the dynamic spring constant as the whole rubber elastic body. As a result, in this embodiment, even if the vibration input is increased, the fluctuation of the resonance frequency of the dynamic damper is suppressed, and the vibration damping performance is appropriately exhibited. For example, in the case of a dynamic damper having a resonance frequency of 100 Hz when the magnitude of the vibration input is 1 G, even if the magnitude of the vibration input is increased to 3 G, the resonance frequency is 96 Hz, which is lower than that of the conventional example of 92 Hz. The degree of decline is greatly reduced. Therefore, the dynamic damper according to the present embodiment is preferably used in a portion where a large vibration input is applied, such as an engine or a transmission.
[0024]
As a modification of the above-described embodiment, as shown in FIGS. 6 and 7, the rubber elastic body protruding portion 23 is formed into a rectangular pyramid-shaped base portion 24 that protrudes to the vicinity of the inner peripheral surface of the outer cylindrical metal member 13 that is long in the axial direction. The small protrusion 25 that partially protrudes from the center of the tip surface can be provided. As described above, since the distal end side of the rubber elastic body projecting portion 23 is the small projecting portion 25, the degree of compressive deformation gradually increases as the vibration input increases. Therefore, similarly to the first embodiment, it is possible to appropriately compensate for fluctuations in the dynamic spring constant of the rubber elastic body connecting portion 15.
[0025]
Next, a second embodiment will be described.
In the present embodiment, as shown in the first embodiment and the modification, the rubber elastic body projecting portions 17 and 23 are provided on the outer peripheral surface of the inner cylindrical metal member 11, and the tip portion is the inner peripheral surface of the outer cylindrical metal member 13. 8 and 9, a pair of substantially rectangular pyramid-shaped rubber elastic body protrusions 27 are bonded to both inner peripheral surfaces of the outer cylindrical metal member 13 in the vibration input direction, as shown in FIGS. The protrusion 19 is protruded into the portion 19, and the protruded tip is brought into non-adhesive contact with the thin rubber covering portion 15 a extending from the rubber elastic body connecting portion 15 on both outer peripheral surfaces of the inner cylinder fitting 11. . Also in the second embodiment configured as described above, as in the first embodiment, even if the vibration input is increased, the rubber elastic body projecting portion 27 appropriately changes the dynamic spring constant of the rubber elastic body connecting portion 15. Can be compensated for. As a result, also in the second embodiment, the fluctuation of the resonance frequency of the dynamic damper can be suppressed, and the vibration damping performance of the dynamic damper can be appropriately exhibited. In addition, about the shape of a rubber elastic body protrusion part, as shown in the said modification, it is good also as a shape which provided the small projection part in the front end surface of the square pyramid part.
[0026]
Note that the dynamic damper of the present invention is not limited to a vehicle and can be used for other similar purposes. In addition, about the dynamic damper shown in the said embodiment, it is an example and can be implemented with a various form in the range which does not deviate from the summary of this invention.
[0027]
【The invention's effect】
According to the first and second aspects of the present invention, the rubber elastic body protruding portion that is bonded and fixed to one of the outer peripheral surface of the inner cylinder fitting and the inner peripheral surface of the outer cylinder fitting orthogonal to the rubber elastic body connecting portion. And the elastic end of the rubber elastic body can compensate for fluctuations in the dynamic spring constant of the connecting portion of the elastic elastic body. The fluctuation of the resonance frequency of the damper is suppressed, and the vibration damping performance is properly exhibited.
[0028]
Moreover, the shape of the tip of the rubber elastic body protruding portion is made to protrude in a substantially triangular cross section or a small protruding portion that partially protrudes, so that the effect of correcting the fluctuation of the dynamic spring constant of the rubber elastic body connecting portion is improved. It is definitely obtained.
[Brief description of the drawings]
1 is a cross-sectional view taken along the line II of FIG. 2, showing a dynamic damper according to a first embodiment of the present invention.
FIG. 2 is a partially broken side view in which a right half showing the dynamic damper is broken at an intermediate position in the axial direction.
3 is a cross-sectional view taken along the line III-III of FIG. 4 showing a rubber bush of the dynamic damper.
FIG. 4 is a partially broken side view in which a right half showing the rubber bush is broken at an intermediate position in the axial direction.
FIG. 5 is a graph schematically showing a relationship between a deflection of a rubber elastic body due to vibration input of a dynamic damper and a dynamic load.
6 is a cross-sectional view taken along the line VV of FIG. 6 showing a dynamic damper according to a modification.
FIG. 7 is a partially broken side view in which the right half of the dynamic damper is broken at an axially intermediate position.
8 is a cross-sectional view taken along line VIII-VIII in FIG. 9 showing a dynamic damper according to a second embodiment.
FIG. 9 is a partially broken side view in which the right half of the dynamic damper is broken at an axially intermediate position.
10 is a cross-sectional view in the XX line direction of FIG. 11 showing a conventional dynamic damper.
FIG. 11 is a partially broken side view in which a right half showing the dynamic damper is broken at an intermediate position in the axial direction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Rubber bush, 11 ... Inner cylinder metal fitting, 13 ... Outer cylinder metal fitting, 15 ... Rubber elastic body connection part, 17, 23, 27 ... Rubber elastic body protrusion part, 18b ... Tip part, 21 ... Mass metal fitting, 25 ... Small protrusion.

Claims

An inner cylinder fitting, an outer cylinder fitting arranged coaxially and spaced apart on the outer peripheral side of the inner cylinder fitting, and between the opposing surfaces of the inner cylinder fitting and the outer cylinder fitting so as to be orthogonal to the vibration input direction A pair of rubber elastic body connecting portions that extend in the radial direction and elastically connect between the inner tube fitting and the outer tube fitting and receive a vibration input applied to the inner tube fitting to be subjected to shear deformation, and the inner tube A rubber bush provided with a metal fitting and a pair of space portions penetrating in the axial direction on both sides in the vibration input direction across the pair of rubber elastic body connecting portions;
A dynamic damper comprising a cylindrical mass fitting fixed to the outer cylinder fitting by being press-fitted into the outer peripheral surface of the outer cylinder fitting of the rubber bush;
Adhered to either one of the outer peripheral surface of the inner cylindrical metal fitting and the inner peripheral surface of the outer cylindrical metal fitting facing the vibration input direction, the outer peripheral surface of the inner cylindrical metal fitting and the outer cylindrical metal fitting inside the space portion A pair of rubber elastic body protrusions protruding toward the other of the inner peripheral surface of the inner surface and the protruding tip non-adhering to the other surface are provided, the rubber elastic body protrusions are chevron-shaped and the tip side is substantially triangular in cross section The rubber elastic body protruding portion is compressed and deformed in response to vibration input to compensate for fluctuations in the dynamic spring constant of the rubber elastic body connecting portion due to fluctuations in vibration input , and has a large amplitude. The dynamic damper is characterized in that the dynamic spring characteristic at the time approximates the dynamic spring characteristic at a small amplitude .

An inner cylinder fitting, an outer cylinder fitting arranged coaxially and spaced apart on the outer peripheral side of the inner cylinder fitting, and a direction perpendicular to the vibration input direction between the opposing surfaces of the inner cylinder fitting and the outer cylinder fitting A pair of rubber elastic body connecting portions that extend in the radial direction and elastically connect between the inner tube fitting and the outer tube fitting and receive a vibration input applied to the inner tube fitting to be subjected to shear deformation, and the inner tube A rubber bush provided with a metal fitting and a pair of space portions penetrating in the axial direction on both sides in the vibration input direction across the pair of rubber elastic body connecting portions;
A dynamic damper comprising a cylindrical mass fitting fixed to the outer cylinder fitting by being press-fitted into the outer peripheral surface of the outer cylinder fitting of the rubber bush;
Adhered to either one of the outer peripheral surface of the inner cylindrical metal fitting and the inner peripheral surface of the outer cylindrical metal fitting facing the vibration input direction, the outer peripheral surface of the inner cylindrical metal fitting and the outer cylindrical metal fitting in the space A pair of rubber elastic body protrusions protruding toward the other of the inner peripheral surface of the inner surface and the protruding tip abutting against the other surface in a non-adhesive manner are provided . It has a small protrusion, which the rubber elastic body protruding portion to compensate for variations in the dynamic spring constant of the rubber elastic body connecting part due to variations in the vibration input by compressive deformation in accordance with the vibration input, large A dynamic damper characterized in that a dynamic spring characteristic at an amplitude approximates a dynamic spring characteristic at a small amplitude .