主軸回転速度振動を伴う再生型旋削びびり (第2報)

Abstract

In the previous paper, the variation of the regenerative chatter stability accompanied with the rotational speed vibration coupling was discussed by paying an attention to the vibration amplitude. In this paper, a model analysis is carried out from the viewpoint of the energy state of the regenerative chatter system to investigate the mechanism of this stability variation. And then, experimental results are re-examined about the phase characteristics of modulations and speed vibration whose important roles in the stability variation have been proved from this analysis. Main results are as follows : (1) It has been analytically shown that under some phase conditions the vibratory energy of the regenerative chatter system coupled with speed vibration becomes larger than that of uncoupled cases. This assures the unstabilization effect experimentally observed. (2) Phase-conditions of modulations and speed vibration are closely related to the aspect of the regenerative chatter, and peculiar phasic diagrams are observed respectively for the primary, transient and steady-state stage of the chatter. (3) On the case where the remarkable unstabilization caused by the speed vibration coupling is observed, such phase conditions as make the vibratory energy state of the regenerative chatter system a local maximum are generally chosen, and this encourages the development of the chatter.