Abstract: It is required that dual mass flywheel of small torsion and low torque should be flexible, while high torque and large torsion should be of high counter torque. According to this requirement, and combining with the engineering design of product R&D, research and practice are devoted into realizing the design object that the dual mass flywheel with circumferential short spring can reach the standard of continuous variable stiffness, which creatively propose the solution that shape constraint can be accomplished in the way of altering the internal contact profile of primary flywheel. Besides, selection principle of curve has been suggested by analyzing and comparing the structure of shape constraint. Based on the study of the torque characteristics of dual mass flywheel on shape constraint, the analytical mode has been built by comparing the simulation calculation results and the experimental measurements. Through analyzing the impact of torsional stiffness k1 and k2 on the driven system’s first and second-order’s resonance speed, it is concluded that k2 is not sensitive to the first-order’s resonance speed, instead, the second-order’s resonance can be affected evidently. On the condition of small torsion angle, the reduction of k1 can keep the first-order’s resonance far away from idling speed, which can keep the resonance being averted completely. Moreover, case study has been made in the mechanical characteristics lying in torsional stiffness and the resonance speed of the dual mass flywheel based on shape constraint, showing that the non-linear torque characteristics of the continuous variable stiffness is of great advantage that a simpler structure can fulfill the expectation of required torque, stiffness and vibration isolation.

Key words: Dual mass flywheel, Mechanical vibration, Shape constraint, Torque characteristics, Torsional damper