Vibration distribution over support system of machine tools under ball-rod hardening of wheelpair assemblies

Introduction. Acoustic field in the allowable zone of the equipment operators, and, in particular, under ball-rod hardening of wheelpairs, is generated by the simultaneous emission of sound energy from two sources. The first one is the acoustic subsystem of “hardenable workpiece - reinforcer”. The second source includes all elements of the supporting machine system, in particular, spindle head housings, foundation slab, etc. When measuring sound pressure levels, it is practically impossible to detect the contribution from each separate source, therefore it is needed to carry out experimental studies on the distribution of vibrations throughout the entire machine carrier system both at idle speed and under the process implementation. Materials and Methods. Measurements of the vibration levels were carried out under certain technological operations. Roll surface machining was performed on a wheel-turning lathe on which ball-rod reinforcers were installed instead of cutting tools. Hard-facing of the landing surfaces of the wheelpair axles was carried out on a purpose-designed axle turning lathe on which the ball-rod reinforcers were installed in place of the cutters. Hard-facing of the wheel landing surface was carried out on a boring-and-turning lathe. In all these cases, octave vibration levels were measured at idle and under hardening. Comparison of the vibration spectra and noise spectra makes it possible to determine implicitly the contribution of the machine carrier system elements to the sound field at the operators' workplaces. Research Results. The research objectives, the results of which are given, consisted in studying the regularities in the distribution of vibration levels throughout the elements of the bearing systems of the ball-rod hardening equipment for wheelpairs. A qualitative assessment of the contribution of each source (hardenable part, reinforcer, and elements of the supporting system) can be performed on the basis of comparing the noise and vibration spectra. Measurements were carried out on three types of machines: special wheel-turning lathe on which the rolling surface is hardened; purpose-designed axle turning lathe on which the landing surface of the wheelpair axle is strengthened; and boring-and-turning lathe on which the wheel opening is reinforced. Discussion and Conclusions. The results of vibration measurements show that the intensity of sound emission of the machine carrier system elements does not cause excess over the sanitary norms of noise. Thus, the development of a noise-vibration protection system can be limited to the “hardenable workpiece - reinforcer” subsystem.