PURPOSE: To provide a vibration damping device being a torsional damper which is constituted to effect stepped control of generating friction torque according to a twist angle.
CONSTITUTION: A torsional damper 3 to drive and intercouple a crank shaft 1 and a torque converter 2 under buffering comprises drive plates 5a and 5b coupled to a crank shaft 1; a driven plate 6 coupled to a torque converter cover 2; and a torsion spring 7. A friction member 8 is fitted in a peripheral oblong hole 6a formed in the driven plate 6, effects frictional engagement with the inner peripheral surfaces, positioned facing an axial direction, of the drive plates 5a and 5b, and provides left and right Δ1 and Δ2 in a peripheral direction between the oblong hole 6a and the friction member and a gap 6 on the inner peripheral side in a radial direction. When an inclination angle of the oblong hole 6a with the radius (r) of a central shaft is θ, δ is set so as to establish a formula of δ<(Δ1+Δ2) tanθ.
MORISHITA TATSUYA
MORIMOTO YOSHIRO
NISSAN MOTOR