OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 Fig. 6. Spectral composition of GW 2 natural vibration frequencies and mechanical properties of the material, which remained unchanged. At the same time, we recorded significant changes in the spectral pattern of the NVF distribution, indicating the independence of the SI and NVF parameters. We thus established that wheels of various geometric shapes studied herein are characterized by the different spectral composition of natural frequencies. At this stage of study, these differences do not show any regularity. Acoustic signals accompanying the idle operation of the 3G71M flat surface grinding machine We studied the acoustic signal accompanying the operation of the 3G71M machine systems. Using a microphone, we recorded acoustic signals accompanying the series connection of the systems: (1) power supply; (2) hydraulic power plant; (3) spindle rotation; and (4) longitudinal pendulum feed of the table (Vs). Table 3 shows spectrograms which reflect the acoustic vibration frequency distribution for the recorded signals. At the first stage, we recorded a signal from the operation of the power supply system only, while at the last stage, – from all the above systems. Since dry grinding is used during the experiment, we did not need to take into account the operation of the coolant supply system. Analysis of the spectrum of acoustic vibrations of the process system (PS) elements showed that the grinding wheel spindle rotation made the maximum contribution to the acoustic picture of the idle machine operation (Table 3, (3)). A significant increase in the sound level in a wide frequency range (from 2 to 7.5 kHz) reached about 26% (Fig. 7) relative to the stage involving the power supply and hydraulic systems. This is caused by the combined action of the individual units of the grinding head: M3 electric motor of the grinding wheel (2.2 kW, 2,860 rpm, 50 Hz, version M101 with KZ MRTU16 – 510.002–65 AOL2 – 22 – 2 – CI terminal box); flat belt pulleys; three-point bearings; spindle; grinding wheel. The acoustic signal corresponding to the operation of the hydraulic power plant was reflected in the frequency range of 250 – 650Hz as a stable excess kurtosis recorded on each of the presented spectrograms (except the first one). The sound level is pulsating in time, corresponding to the operating features of the oil pump. The sound level is from –17 dB to –50 dB. The systems of power supply and longitudinal feed of the table (Table 3 (1), (4)) do not generate significant acoustic disturbances of the process system elements, do not introduce significant changes in the overall acoustic picture of the idle operation of the experimental setup.
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