【０００１】
【発明の属する技術分野】
本発明は、回転軸を挿通させる筒状の質量部材と、前記質量部材の両側で前記回転軸に外嵌固定される一対の固定部とをそれらの軸芯方向で連結し、前記質量部材の一端部と一方の固定部の間に第１ゴム状弾性体を介在させ、前記質量部材の他端部と他方の固定部の間に第２ゴム状弾性体を介在させてあるダイナミックダンパに関する。
【０００２】
【従来の技術】
自動車のドライブシャフト等の回転軸には回転のアンバランス等に起因して振動が生じ、この振動がサスペンションを介して車内に伝わって騒音が発生することがある。このような場合、固有振動数を回転軸の共振振動数にチューニングしたダイナミックダンパを回転軸に外嵌固定し、回転軸の振動エネルギーを共振によりダイナミックダンパの振動エネルギーとして吸収することで振動を抑制している。
【０００３】
近年、ダイナミックダンパの改良が進み、冒頭に記載したような構造のダイナミックダンパも開発されている。この構造によれば、質量部材と固定部が回転軸の径方向で重ならないので小径化でき、第１ゴム状弾性体と第２ゴム状弾性体にせん断力が加わるのでばね定数を小さくすることができて、低い固有振動数に設定できる。
【０００４】
しかしながら、この種のダイナミックダンパでは、前記固有振動数を単一の共振振動数域にしか設定できず、振動数の異なる複数の振動の入力がある場合、振動を十分抑制することができない。
【０００５】
そこで、従来、特許文献１に開示されているように、第１ゴム状弾性体と第２ゴム状弾性体を、質量部材の軸芯を挟んで位置する複数対のゴム状弾性体部分から構成し、前記複数対のゴム状弾性体部分の径方向の肉厚を各対ごとに異ならせたダイナミックダンパが開発されていた。
【０００６】
【特許文献１】
特開平９−８９０４７号公報
【０００７】
【発明が解決しようとする課題】
上記従来の技術によれば、第１ゴム状弾性体側の厚肉部（又は薄肉部）の位置と、第２ゴム状弾性体側の厚肉部（又は薄肉部）の位置とを周方向で一致させなければならず、成形型の製作に手間がかかっていた。すなわち、第１ゴム状弾性体と第２ゴム状弾性体が質量部材の両側に位置して離れているために、第１ゴム状弾性体側の厚肉部（又は薄肉部）に対応する成形型部分と、第２ゴム状弾性体側の厚肉部（又は薄肉部）に対応する成形型部分とを、それらの周方向の位置が合うように加工するのに手間がかかって製作コストが高くなるという問題があった。
【０００８】
本発明の目的は、コンパクト化できるとともに、ばね定数を小さくすることができて低い固有振動数に設定することができ、振動数の異なる複数の振動の入力がある場合でも振動を十分抑制することができ、しかも製作コストを低廉化できるダイナミックダンパを提供する点にある。
【０００９】
【課題を解決するための手段】
本発明の特徴構成は、回転軸を挿通させる筒状の質量部材と、前記質量部材の両側で前記回転軸に外嵌固定される一対の固定部とをそれらの軸芯方向で連結し、前記質量部材の一端部と一方の固定部の間に第１ゴム状弾性体を介在させ、前記質量部材の他端部と他方の固定部の間に第２ゴム状弾性体を介在させてあるダイナミックダンパであって、
前記質量部材の軸芯方向で前記質量部材の内周面の中間部に、前記質量部材の軸芯を挟んで位置する複数対の第３ゴム状弾性体を突設するとともに、各対ごとに、前記軸芯方向における前記第３ゴム状弾性体の幅を異ならせ、前記複数対の第３ゴム状弾性体が前記回転軸に外嵌固定され、前記第３ゴム状弾性体の幅方向の両側で、前記回転軸の外周面と質量部材との間に空間が形成されるよう構成してある点にある。
【００１０】
この構成によれば、質量部材と一対の固定部が回転軸の径方向で重ならないので外径を小さくすることができる。そして、第１ゴム状弾性体と第２ゴム状弾性体にせん断力が加わるので、ばね定数を小さくすることができる。
【００１１】
質量部材の軸芯方向で質量部材の内周面の中間部に、例えば、質量部材の軸芯を挟んで位置する一対の第３ゴム状弾性体と、これよりも幅狭の別の一対の第３ゴム状弾性体とを突設した構造の場合（以下、前者を「幅広の一対の第３ゴム状弾性体」、後者を「幅狭の一対の第３ゴム状弾性体」と称する）、これら二対の第３ゴム状弾性体が回転軸に外嵌固定され、各第３ゴム状弾性体の幅方向の両側で、回転軸の外周面と質量部材との間に空間が形成される。
【００１２】
そして、幅広の一対の第３ゴム状弾性体の中央部と交差する第１方向では、第３ゴム状弾性体が質量部材を支持しているので、質量部材の内周面に第３ゴム状弾性体を突設してない構造よりもばね定数が高くなり、回転軸が振動すると、所定の値よりも高い固有振動数で共振して回転軸の振動を吸収する。
【００１３】
幅狭の一対の第３ゴム状弾性体の中央部と交差する第２方向では、第３ゴム状弾性体が質量部材を支持しているので、質量部材の内周面に第３ゴム状弾性体を突設してない構造よりもばね定数が高くなるが、前記第１方向よりもばね定数が小さくなり、回転軸が振動すると、前記所定の値よりも低い固有振動数で共振して回転軸の振動を吸収する。
【００１４】
幅広の一対の第３ゴム状弾性体の端部（周方向の端部）側と交差する方向や、幅狭の一対の第３ゴム状弾性体の端部（周方向の端部）側と交差する方向では、高低の中間の値の固有振動数で共振して回転軸の振動を吸収する。このように、ダイナミックダンパの固有振動数を回転軸の複数の共振振動数域にチューニングすることができる。質量部材の内周面の中間部に、三対以上の第３ゴム状弾性体を突設した場合も上記と同様の作用を奏することができる。
【００１５】
また、質量部材の軸芯方向で質量部材の内周面の中間部に、質量部材の軸芯を挟んで位置する複数対の第３ゴム状弾性体を突設するから、成形型を製作する場合は、第３ゴム状弾性体に対応する成形型部分を、質量部材の軸芯方向に対応する方向に一連に形成することができて、従来の技術のような、互いに離れた一対の成形型部分の位置決めが不要であり、成形型を容易に製作することができる。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。図１，図２，図３に、自動車のドライブシャフトＳ（回転軸に相当）の振動を抑制する筒型のダイナミックダンパを示してある。
【００１７】
このダイナミックダンパは、ドライブシャフトＳを挿通させる金属円筒状の質量部材１と、質量部材１の両側でドライブシャフトＳに外嵌固定される一対の円筒状の固定部２，３とをそれらの軸芯方向で連結し、質量部材１の軸芯方向の一端部１Ａと一方の固定部２との間に第１ゴム状弾性体４を介在させ、質量部材１の他端部１Ｂと他方の固定部３との間に第２ゴム状弾性体５を介在させて構成してある。
【００１８】
また、質量部材１の軸芯方向で質量部材１の内周面の中央部（中間部に相当）に、質量部材１の軸芯Ｏを挟んで位置する二対の第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂを突設するとともに、一対の第３ゴム状弾性体６Ａ，６Ｂと別の一対の第３ゴム状弾性体６Ａ，６Ｂとの前記軸芯方向における幅を異ならせてある。詳しくは、前記一対の第３ゴム状弾性体６Ａ，６Ｂの幅を別の一対のゴム状弾性体９Ａ，９Ｂの幅よりも大きく設定して、各対ごとに、前記軸芯方向における第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂの幅を異ならせてある。一対の第３ゴム状弾性体６Ａ，６Ｂの幅方向の中心と、別の一対のゴム状弾性体９Ａ，９Ｂの幅方向の中心とは前記軸芯方向で同一位置（質量部材１の前記軸芯方向の中央）に位置している。
【００１９】
そして、前記二対の第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９ＢがドライブシャフトＳに圧入・外嵌固定され、第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂの幅方向の両側で、ドライブシャフトＳの外周面１４と質量部材１との間に空間Ａが形成されるよう構成してある。
【００２０】
前記一対の第３ゴム状弾性体６Ａ，６Ｂ同士は互いに同一形状で、共に質量部材１の内周面に沿う円弧状に形成され、質量部材１の軸芯Ｏに対して点対称に位置している。別の一対の第３ゴム状弾性体９Ａ，９Ｂ同士も互いに同一形状で、共に質量部材１の内周面に沿う円弧状に形成され、質量部材１の軸芯Ｏに対して点対称に位置している。
【００２１】
前記一対の第３ゴム状弾性体６Ａ，６Ｂの周方向における長さは、別の一対の第３ゴム状弾性体９Ａ，９Ｂの周方向における長さよりも少し長く、これら二対の第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂが周方向にリング状に連なって、質量部材１の全周にわたっている。
【００２２】
質量部材１の内周面には、第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂよりも薄肉の第４ゴム状弾性体７を加硫成形してあり、この第４ゴム状弾性体７の内周面からの各第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂの突出量を同一に設定してある。
【００２３】
二対の第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂから成るリング部は、質量部材１及び一対の固定部２，３と同芯で、その内径は一対の固定部２，３の内径よりも小さい。つまり、質量部材１の軸芯方向視で、各第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂが一対の固定部２，３の内周面２Ａ，３Ａから前記軸芯Ｏ側に少し突出している。
【００２４】
前記一方の固定部２は第５ゴム状弾性体から成り、他方の固定部３は第６ゴム状弾性体から成る。これらは第４ゴム状弾性体７を介して連なっている。第１〜第６ゴム状弾性体は、同一のゴム配合物によって同一の成形型内で質量部材１に対して一体に加硫成形される。
【００２５】
両固定部２，３の外周部に、締付けバンド（図示せず）を巻回するための環状の溝１３をそれぞれ形成し、ドライブシャフトＳに強く固定することができるようにしてある。
【００２６】
前記空間Ａは、第４ゴム状弾性体７の内周面とドライブシャフトＳの外周面１４との間に形成されており、第１ゴム状弾性体４の一部分とドライブシャフトＳの外周面１４との間、及び、第２ゴム状弾性体５の一部分とドライブシャフトＳの外周面１４との間にも入り込んでいる。
【００２７】
ドライブシャフトＳに固定された上記構造のダイナミックダンパに振動が入力すると、前記一対の第３ゴム状弾性体６Ａ，６Ｂの中央部と交差する図３のＸ−Ｘ方向で、所定の値よりも高い固有振動数で共振してドライブシャフトＳの振動を吸収する。そして、前記別の一対の第３ゴム状弾性体９Ａ，９Ｂの中央部と交差する図３のＹ−Ｙ方向で、前記所定の値よりも低い固有振動数で共振してドライブシャフトＳの振動を吸収する。
【００２８】
［別実施形態］
（１）前記ドライブシャフトＳの外周部に、前記二対の第３ゴム状弾性体６Ａ，６Ｂ，９Ａ，９Ｂに嵌合する環状の嵌合溝を形成してあってもよい。この構成によれば、ドライブシャフトＳからダイナミックダンパが抜けにくくなる。
【００２９】
（２）質量部材１の軸芯方向で質量部材１の内周面の中間部に、質量部材１の軸芯Ｏを挟んで位置する三対以上の第３ゴム状弾性体を突設してあってもよい。
【００３０】
（３）上記構造のダイナミックダンパを取付ける対象はドライブシャフト以外に、自動車のプロペラシャフトや自動車のその他の回転軸であってもよく、自動車以外の装置の回転軸であってもよい。
【００３１】
【発明の効果】
本発明によれば、コンパクト化できるとともに、ばね定数を小さくすることができて低い固有振動数に設定することができ、振動数の異なる複数の振動の入力がある場合でも振動を十分抑制することができ、しかも製作コストを低廉化できるダイナミックダンパを提供することができた。
【図面の簡単な説明】
【図１】ダイナミックダンパの側面図
【図２】図１のＡ−Ｏ−Ａ断面図
【図３】図２のＢ−Ｂ矢視図
【符号の説明】
１ 質量部材
１Ａ 質量部材の一端部
１Ｂ 質量部材の他端部
２ 固定部
３ 固定部
４ 第１ゴム状弾性体
５ 第２ゴム状弾性体
６Ａ，６Ｂ，９Ａ，９Ｂ第３ゴム状弾性体
１４ 回転軸の外周面
Ｏ 質量部材の軸芯
Ｓ 回転軸
Ａ 空間[0001]
BACKGROUND OF THE INVENTION
The present invention connects a cylindrical mass member through which a rotary shaft is inserted and a pair of fixing portions that are externally fixed to the rotary shaft on both sides of the mass member in the axial direction of the mass member. The present invention relates to a dynamic damper in which a first rubber-like elastic body is interposed between one end portion and one fixing portion, and a second rubber-like elastic body is interposed between the other end portion of the mass member and the other fixing portion.
[0002]
[Prior art]
Vibrations may occur on a rotating shaft such as a drive shaft of an automobile due to rotation imbalance, etc., and this vibration may be transmitted to the interior of the vehicle via a suspension to generate noise. In such a case, a dynamic damper whose natural frequency is tuned to the resonance frequency of the rotating shaft is externally fitted to the rotating shaft, and vibration is suppressed by absorbing the vibration energy of the rotating shaft as vibration energy of the dynamic damper by resonance. is doing.
[0003]
In recent years, dynamic dampers have been improved, and dynamic dampers having the structure described at the beginning have also been developed. According to this structure, since the mass member and the fixed portion do not overlap in the radial direction of the rotating shaft, the diameter can be reduced, and a shear force is applied to the first rubber-like elastic body and the second rubber-like elastic body, so that the spring constant is reduced. Can be set to a low natural frequency.
[0004]
However, in this type of dynamic damper, the natural frequency can be set only in a single resonance frequency range, and vibrations cannot be sufficiently suppressed when there are a plurality of vibration inputs having different frequencies.
[0005]
Therefore, conventionally, as disclosed in Patent Document 1, the first rubber-like elastic body and the second rubber-like elastic body are composed of a plurality of pairs of rubber-like elastic body portions located with the axis of the mass member interposed therebetween. However, dynamic dampers have been developed in which the radial thicknesses of the plurality of pairs of rubber-like elastic body portions are different for each pair.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-89047
[Problems to be solved by the invention]
According to the above conventional technique, the position of the thick part (or thin part) on the first rubber-like elastic body side and the position of the thick part (or thin part) on the second rubber-like elastic body side coincide with each other in the circumferential direction. It had to be made, and it took time and effort to manufacture the mold. That is, since the first rubber-like elastic body and the second rubber-like elastic body are located and separated on both sides of the mass member, the molding die corresponding to the thick part (or thin part) on the first rubber-like elastic body side It takes time and effort to process the part and the mold part corresponding to the thick part (or thin part) on the second rubber-like elastic body side so that their positions in the circumferential direction match, and the manufacturing cost increases. There was a problem.
[0008]
The object of the present invention is to be compact, to be able to reduce the spring constant and to be set to a low natural frequency, and to sufficiently suppress vibration even when there are a plurality of vibration inputs having different frequencies. It is possible to provide a dynamic damper that can reduce the manufacturing cost.
[0009]
[Means for Solving the Problems]
The characteristic configuration of the present invention includes a cylindrical mass member through which a rotation shaft is inserted, and a pair of fixing portions that are fitted and fixed to the rotation shaft on both sides of the mass member, in the axial direction thereof, A first rubber-like elastic body is interposed between one end of the mass member and one fixing portion, and a second rubber-like elastic body is interposed between the other end of the mass member and the other fixing portion. A damper,
In the axial direction of the mass member, a plurality of pairs of third rubber-like elastic bodies positioned between the mass member's axial centers are provided in the middle of the inner peripheral surface of the mass member, and for each pair. , Different widths of the third rubber-like elastic body in the axial direction, the plurality of pairs of third rubber-like elastic bodies are fitted and fixed to the rotary shaft, and the width direction of the third rubber-like elastic body is On both sides, a space is formed between the outer peripheral surface of the rotating shaft and the mass member.
[0010]
According to this configuration, since the mass member and the pair of fixed portions do not overlap in the radial direction of the rotation shaft, the outer diameter can be reduced. Since a shearing force is applied to the first rubber-like elastic body and the second rubber-like elastic body, the spring constant can be reduced.
[0011]
In the middle part of the inner peripheral surface of the mass member in the axial direction of the mass member, for example, a pair of third rubber-like elastic bodies positioned across the axis of the mass member and another pair of narrower widths than this In the case of a structure in which a third rubber-like elastic body is protruded (hereinafter, the former is referred to as “a pair of wide third rubber-like elastic bodies” and the latter is referred to as “a pair of narrow third rubber-like elastic bodies”). These two pairs of third rubber-like elastic bodies are fitted and fixed to the rotation shafts, and a space is formed between the outer peripheral surface of the rotation shaft and the mass member on both sides of each third rubber-like elastic body in the width direction. The
[0012]
And in the 1st direction which intersects the central part of a pair of wide 3rd rubbery elastic bodies, since the 3rd rubbery elastic body is supporting the mass member, it is the 3rd rubber-like on the inner peripheral surface of a mass member. When the spring constant becomes higher than that of the structure without protruding elastic bodies and the rotating shaft vibrates, it resonates at a natural frequency higher than a predetermined value and absorbs the vibration of the rotating shaft.
[0013]
In the second direction intersecting with the center portion of the pair of narrow third rubber-like elastic bodies, the third rubber-like elastic body supports the mass member, so that the third rubber-like elasticity is formed on the inner peripheral surface of the mass member. The spring constant is higher than that of the structure in which the body is not protruded, but when the spring constant is smaller than that in the first direction and the rotating shaft vibrates, it resonates and rotates at a natural frequency lower than the predetermined value. Absorbs shaft vibration.
[0014]
The direction intersecting the end (circumferential end) side of the pair of wide third rubber-like elastic bodies, and the end (circumferential end) side of the pair of narrow third rubber-like elastic bodies In the intersecting direction, it resonates at a natural frequency of an intermediate value between high and low to absorb the vibration of the rotating shaft. Thus, the natural frequency of the dynamic damper can be tuned to a plurality of resonance frequency ranges of the rotating shaft. Even when three or more pairs of third rubber-like elastic bodies are provided in the middle of the inner peripheral surface of the mass member, the same effect as described above can be obtained.
[0015]
In addition, since a plurality of pairs of third rubber-like elastic bodies are provided in the middle of the inner peripheral surface of the mass member in the axial direction of the mass member so as to sandwich the mass member's axis, the molding die is manufactured. In this case, the mold part corresponding to the third rubber-like elastic body can be formed in series in the direction corresponding to the axial direction of the mass member, and a pair of moldings separated from each other as in the conventional technique Positioning of the mold part is unnecessary, and the mold can be easily manufactured.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1, 2, and 3 show a cylindrical dynamic damper that suppresses vibration of a drive shaft S (corresponding to a rotating shaft) of an automobile.
[0017]
The dynamic damper includes a metal cylindrical mass member 1 through which the drive shaft S is inserted, and a pair of cylindrical fixing portions 2 and 3 that are externally fixed to the drive shaft S on both sides of the mass member 1. The first rubber-like elastic body 4 is interposed between one end 1A in the axial direction of the mass member 1 and the one fixing portion 2, and the other end 1B of the mass member 1 is fixed to the other end. A second rubber-like elastic body 5 is interposed between the portion 3 and the portion 3.
[0018]
In addition, two pairs of third rubber-like elastic bodies 6 </ b> A located in the center part (corresponding to an intermediate part) of the inner peripheral surface of the mass member 1 with the axis O of the mass member 1 in between in the axial direction of the mass member 1. , 6B, 9A, 9B, and a pair of third rubber-like elastic bodies 6A, 6B and another pair of third rubber-like elastic bodies 6A, 6B have different widths in the axial direction. . Specifically, the width of the pair of third rubber-like elastic bodies 6A, 6B is set to be larger than the width of another pair of rubber-like elastic bodies 9A, 9B, and the third in the axial direction is set for each pair. The rubber-like elastic bodies 6A, 6B, 9A, and 9B have different widths. The center in the width direction of the pair of third rubber-like elastic bodies 6A and 6B and the center in the width direction of another pair of rubber-like elastic bodies 9A and 9B are the same position in the axial direction (the axis of the mass member 1 It is located in the center of the core direction.
[0019]
Then, the two pairs of third rubber-like elastic bodies 6A, 6B, 9A, 9B are press-fitted and externally fixed to the drive shaft S, and on both sides in the width direction of the third rubber-like elastic bodies 6A, 6B, 9A, 9B. The space A is formed between the outer peripheral surface 14 of the drive shaft S and the mass member 1.
[0020]
The pair of third rubber-like elastic bodies 6A, 6B have the same shape, are formed in an arc shape along the inner peripheral surface of the mass member 1, and are positioned point-symmetrically with respect to the axis O of the mass member 1. ing. Another pair of third rubber-like elastic bodies 9A and 9B are also in the same shape and are formed in an arc shape along the inner peripheral surface of the mass member 1, and are positioned symmetrically with respect to the axis O of the mass member 1. is doing.
[0021]
The length in the circumferential direction of the pair of third rubber-like elastic bodies 6A, 6B is slightly longer than the length in the circumferential direction of another pair of third rubber-like elastic bodies 9A, 9B, and these two pairs of third rubbers The elastic bodies 6A, 6B, 9A, 9B are connected in a ring shape in the circumferential direction and extend over the entire circumference of the mass member 1.
[0022]
On the inner peripheral surface of the mass member 1, a fourth rubber-like elastic body 7 thinner than the third rubber-like elastic bodies 6A, 6B, 9A, 9B is vulcanized and molded. The protruding amounts of the third rubber-like elastic bodies 6A, 6B, 9A, 9B from the inner peripheral surface of the same are set to the same.
[0023]
The ring portion composed of the two pairs of third rubber-like elastic bodies 6A, 6B, 9A, 9B is concentric with the mass member 1 and the pair of fixing portions 2, 3, and the inner diameter thereof is the inner diameter of the pair of fixing portions 2, 3. Smaller than. That is, the third rubber-like elastic bodies 6A, 6B, 9A, 9B slightly protrude from the inner peripheral surfaces 2A, 3A of the pair of fixing portions 2, 3 toward the axis O when viewed from the axial direction of the mass member 1. ing.
[0024]
The one fixing part 2 is made of a fifth rubber-like elastic body, and the other fixing part 3 is made of a sixth rubber-like elastic body. These are connected via a fourth rubber-like elastic body 7. The first to sixth rubber-like elastic bodies are integrally vulcanized and molded with respect to the mass member 1 in the same mold by the same rubber compound.
[0025]
An annular groove 13 for winding a tightening band (not shown) is formed on the outer peripheral portion of both the fixing portions 2 and 3, respectively, so that it can be firmly fixed to the drive shaft S.
[0026]
The space A is formed between the inner peripheral surface of the fourth rubber-like elastic body 7 and the outer peripheral surface 14 of the drive shaft S, and a part of the first rubber-like elastic body 4 and the outer peripheral surface 14 of the drive shaft S are formed. And between the part of the second rubber-like elastic body 5 and the outer peripheral surface 14 of the drive shaft S.
[0027]
When vibration is input to the dynamic damper having the above-described structure fixed to the drive shaft S, the X-X direction in FIG. 3 intersects with the central portion of the pair of third rubber-like elastic bodies 6A and 6B. Resonates at a high natural frequency to absorb the vibration of the drive shaft S. Then, the vibration of the drive shaft S resonates at a natural frequency lower than the predetermined value in the Y-Y direction of FIG. 3 intersecting the central portion of the other pair of third rubber-like elastic bodies 9A, 9B. Absorbs.
[0028]
[Another embodiment]
(1) An annular fitting groove that fits the two pairs of third rubber-like elastic bodies 6A, 6B, 9A, and 9B may be formed on the outer periphery of the drive shaft S. According to this configuration, it is difficult for the dynamic damper to come off from the drive shaft S.
[0029]
(2) Three or more pairs of third rubber-like elastic bodies are provided in the middle of the inner peripheral surface of the mass member 1 in the axial direction of the mass member 1 with the axis O of the mass member 1 interposed therebetween. There may be.
[0030]
(3) In addition to the drive shaft, the target for mounting the dynamic damper having the above structure may be a propeller shaft of an automobile, another rotating shaft of the automobile, or a rotating shaft of a device other than the automobile.
[0031]
【The invention's effect】
According to the present invention, the size can be reduced, the spring constant can be reduced, the natural frequency can be set low, and vibration can be sufficiently suppressed even when there are a plurality of vibration inputs having different frequencies. In addition, it was possible to provide a dynamic damper that can reduce the manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a side view of a dynamic damper. FIG. 2 is a cross-sectional view taken along line A-O-A in FIG. 1. FIG. 3 is a view taken along arrow BB in FIG.
DESCRIPTION OF SYMBOLS 1 Mass member 1A One end part 1B of a mass member The other end part 2 of a mass member 2 Fixed part 3 Fixed part 4 1st rubber-like elastic body 5 2nd rubber-like elastic body 6A, 6B, 9A, 9B 3rd rubber-like elastic body 14 Rotating shaft outer peripheral surface O Mass member axis S Rotating shaft A Space
