ГАШЕНИЕ АВТОКОЛЕБАНИЙ ЗАКРЕПЛЕННОГО В ЦЕНТРАХ НЕЖЕСТКОГО ВАЛА ПРИ ТОЧЕНИИ МНОГОРЕЗЦОВОЙ ГОЛОВКОЙ С ПЕРЕМЕННЫМ ШАГОМ ЗУБЬЕВ

Abstract

The application of intensive modes of cutting while processing movable shafts by multiple-tool heads is contained by the actuation of regenerating autovibrations in the technological system. The authors considered the existing methods of their damping. The application of tool with variable circular tooth pitch is the most advanced method of regenerating autovibrations damping. However, the scientists’ opinions on the desired value of tooth pitch diversity vary. For the experimental determination of this value, the authors developed the structure of the adjustable multiple-tool head and carried out the study of the influence of tooth pitch diversity on the amplitude of movable shaft autovibrations during its turning with fixing it in centers. When adjusting head, the authors used the cycling of the enlarged and reduced tooth pitches. The noncontacting eddy current sensors were used to register the workpiece vertical and horizontal vibrations. Based on the analysis of autovibrations vibration records, their frequency spectra, workpiece motion trajectories and the processed surfaces pictures, the authors detected that the increase in neighbor tooth pitches diversity causes the sequential contraction, the enlargement and the repeated contraction of the autovibrations amplitude. Autovibrations damping takes place when the diversity of circular tooth pitches is within the range of values from 0.25 up to 1.3 of autovibrations wavelength on the cut surface. They were damped almost completely at the value of 0.75. The authors explained the results of received experimental data from the position of the regenerating autovibrations theory. Therefore, it is proved experimentally that the application of multiple-tool heads with the adjustment of circular tooth pitch diversity allows providing the dynamical stability of movable shafts turning process.