NATURAL FREQUENCIES OF MECHANICAL VIBRATIONS IN DRIVES OF PROBE EQUIPMENT WITH TOOTHED BELT GEARS
The article presents the results of research on the rigidity of polyurethane toothed belts used in precision vertical stroke drives of Planar JSC probe installations, the analysis of which showed that the stiffness of these belts in the operating range of loads does not essentially depend on the tensile speed and load, and, with its average value of <i>С</i><sub>р</sub> ~ 105 N/mm, the average square deviation is 7.1 N/mm with a coefficient of variation not exceeding 7 %. For almost all speed modes of tension and loading, the values of mean square deviations were close to each other and their average value was <i>S</i><sub>cp</sub> = 5.3 N/mm, i.e. all the obtained stiffness values are put in the range ~3<i>S</i><sub>cp</sub>. In addition, dispersing the instantaneous stiffness does not much depend on the degree of tension of the toothed belt that makes it possible while constructing the mathematical models of mechanical vibrations of the table with their own frequency to use a fixed stiffness value of polyurethane toothed belt. The approximate values of the frequencies of the natural mechanical vibrations of the table in the vertical direction are determined, which make it possible to technically reasonable select vibration sensors and means for monitoring these vibrations at the <i>Z</i> coordinate.