DYNAMIC DAMPER

PROBLEM TO BE SOLVED: To restrain water from remaining between an elastic member and a shaft member of a dynamic damper. SOLUTION: By forming a penetration hole 3 that penetrates the cylindrical elastic member 1 toward the outside diameter face from the inside diameter side, and by forming a circumferential groove 4a and a spiral groove 4b that continue to the penetration hole 3 on the inside diameter face, water intruded between the elastic member 1 and the shaft member 11 is discharged outside by being led to the penetration hole 3 from the circumferential groove 4a and the spiral groove 4b by a centrifugal force generated accompanied by the rotation of the shaft member 11, and thus the water is restrained from remaining between the elastic member 1 and the shaft member 11. COPYRIGHT: (C)2008,JPO&INPIT