Abstract: A torsional damper comprises: a hub fixed to a rotating shaft and having an outer peripheral surface on the circumference centered on the rotating shaft; an annular vibrating ring having an inner peripheral surface having a diameter larger than that of the outer peripheral surface of the hub, on the circumference centered on the rotation axis; and a rubber ring, composed of a rubber composition containing EPDM as a main component, provided in a compressed state between the outer peripheral surface of the hub and the inner peripheral surface of the vibrating ring, and has a loss coefficient of 0.18 or more when the surface temperature is 60±5° C., wherein when the rubber ring is subjected to the resonance point tracking method, the maximum surface reaching temperature of the rubber ring at the time of continuous vibration at the resonance point and the vibration ring thickness satisfy a specific relational expression.

Abstract: A torsional damper comprises: a hub fixed to a rotating shaft and having an outer peripheral surface on the circumference centered on the rotating shaft; an annular vibrating ring having an inner peripheral surface having a diameter larger than that of the outer peripheral surface of the hub, on the circumference centered on the rotation axis; and a rubber ring, composed of a rubber composition containing EPDM as a main component, provided in a compressed state between the outer peripheral surface of the hub and the inner peripheral surface of the vibrating ring, and has a loss coefficient of 0.18 or more when the surface temperature is 60±5° C., wherein when the rubber ring is subjected to the resonance point tracking method, the maximum surface reaching temperature of the rubber ring at the time of continuous vibration at the resonance point and the vibration ring thickness satisfy a specific relational expression.