Ставится задача выяснения причин потери устойчивости токарного станка при поперечном точении канавок и растачивании. В качестве инструмента анализа состояния конструкции используются возможности модальной диагностики.
In the paper the problem of reasons elucidation in the matter of lathe instability at groove cross turning and boring is solved. As a tool for the analysis of a structure state there are used potentialities of modal monitoring, and in particular, a correlation of modal parameters, sets of proper characteristics of an elastic system (self-frequencies, modal coefficients damping and own forms of vibrations) of lathes designs with the state of bearings in spindle units. The application of a modal approach to the evaluation of a lathe design state or an elastic system is a new section in a dynamic analysis and may be called modal diagnostics. From the analysis of the modal parameter values of a lathe one traces their tie with the lathe design characteristics, and in particular, with the existence of sever rigidity anisotropy of a spindle unit front bearing and also with its insufficient tightness. Reasoning from the information mentioned of the modal parameters connection with the rigidity of a spindle unit front bearing and a state of bearing design the authors draw a conclusion of the technological state of a spindle unit design. In such a way, by the example of the design of two lathes in the paper there is shown a possibility of transition from experimental frequency characteristics through a procedure of modal diagnostics to the evaluation of the technological state of a spindle unit.