Determination of Dynamic Loads on Soil-Preparation Machines Used for Potato Planting
Annotatsiya
Soil preparation prior to planting is a key stage in potato cultivation. The incorporation of a loosening drum into a soil- separating machine helps reduce tuber damage during harvesting. This study presents an experimental approach to investigating the natural oscillation frequencies of the loosening drum, using a soil separator under real working conditions. ( Research purpose ) To identify the patterns governing changes in dynamic loads acting on the working elements of soil-cultivating machines by means of strain-gauge measurements and oscillographic analysis of vibrational processes in the rotating components of a soil clod separator. ( Materials and methods ) To determine the natural oscillation frequencies of the clod-breaking working tools of the separator machine, the method of inertial excitation was used. A special laboratory test rig was constructed, consisting of an MGP-35 type direct current motor, a rectifier equipped with a rheostat, and a strain-gauge beam. During the experiment, a vibrator was mounted on a bracket rigidly fixed to the shaft of the soil loosening drum to identify its natural frequency. The adopted strain-gauge measurement scheme for the rotating units of the soil clod separator ensures high measurement accuracy. Oscillatory responses were recorded using a strain-gauge beam made of spring steel and shaped as a cantilever plate. Two strain gauges with a gauge length of 20 mm and a nominal resistance of 200 Ohms each were bonded to the lateral surfaces of the beam to register deformation caused by vibrational loading. ( Results and discussion ) To determine the natural frequency of the loosening drum, the vibrator was mounted on a drive sprocket with z = 40. The natural frequencies of the first and second shafts of the separating conveyor were determined in a similar manner, with the vibrator mounted on a drive sprocket with z = 13. The strain gauges registered bending deformation of the plate, while the resulting electrical signals were transmitted to an amplifier and subsequently to the oscilloscope galvanometer, which provided continuous recording of oscillograms of torsional vibrations excited by the electric motor. ( Conclusions ) The experimental results demonstrated that the torsional vibration waveforms of the drive and driven shafts of the elevator, as well as of the loosening drum, exhibit a sinusoidal character with a vibration period of T=0.053 seconds.