DYNAMIC DAMPER AND DRIVE SHAFT

PROBLEM TO BE SOLVED: To provide a dynamic damper capable of being fixed to a shaft main body without using a fastening member, and preventing intrusion of moisture to a space between a holding portion of an elastic member for holding a mass member and the shaft main body, and a drive shaft.SOLUTION: A dynamic damper 5 mounted on a mounting portion 23 of a shaft main body 2 provided with a pair of annular step faces 23a, 23b, includes an elastic member 6 for holding a cylindrical mass member 51. The elastic member 6 has a holding portion 60 for holding the mass member 51, first and second cylindrical portions 61, 62 externally fitted to the mounting portion 23, and first and second connecting portions 63, 64 for connecting the first and second cylindrical portions 61, 62 and the holding portion 60 so that a space 50 is formed between the holding portion 60 and the shaft main body 2. The first and second cylindrical portions 61, 62 have first and second seal faces 611b, 622b respectively closely kept into contact with the pair of annular step faces 23a, 23b in an axial direction.SELECTED DRAWING: Figure 3 【課題】締め付け部材を用いることなくシャフト本体への固定することが可能で、かつ質量部材を保持する弾性部材の保持部とシャフト本体との間に空間に水分が浸入することを防ぐことが可能なダイナミックダンパ、及びドライブシャフトを提供する。【解決手段】一対の環状段差面２３ａ，２３ｂが形成されたシャフト本体２の取付部２３に取り付けられるダイナミックダンパ５は、筒状の質量部材５１を保持する弾性部材６を備える。弾性部材６は、質量部材５１を保持する保持部６０と、取付部２３に外嵌される第１及び第２の筒部６１，６２と、保持部６０とシャフト本体２との間に空間５０が形成されるように第１及び第２の筒部６１，６２と保持部６０とをそれぞれ連結する第１及び第２の連結部６３，６４とを有する。第１及び第２の筒部６１，６２は、一対の環状段差面２３ａ，２３ｂにそれぞれ軸方向に密着する第１及び第２のシール面６１１ｂ，６２２ｂを有する。【選択図】図３