Abstract
This paper describes how to increase the stiffness of a servomechanism in a direct- drive NC hobbing machine. Since the equivalent inertia moment of the work-table is very small in the direct-drive NC hobbing machine, the rotating vibration caused by the torque fluctuation of load becomes very large. To solve this problem, the authors tried to apply damping torque to the servomechanism by using an inertial damper. This increased the stiffness without any resonance over a wide frequency range of exciting force. The effect of this inertial damper is verified by theoretical analysis and experiments. Gear-cutting experiments proved that this easy method is practical and useful in decreasing the rotating vibration of the worktable in the cutting process.
