A Study on the Cutting and Vibratory Characteristics of the Eccentrically Rotating Cutter-Bar System

편심회전 봉형 절단장치의 절단 및 진동 특성에 관한 연구

This work was intended to study the cutting graph and vibratory phenomina of a newly developed mower which may be suitable for mowing agricultural product having large and hard stems like corn and sugar beet. The system consists of cutter-bar having Curvilinear-translation motion, which attached to drag-crank mechanism. The motion of equation developed for experimental vibratory system which equipped with the cutter-bar system was established and the parameters defining the system's vibratory motion were experimentally determined. The optimum balancing weight for the cutter-bar am vibratory characteristics of the cutter-bar for various counterweight were analyzed to provide the design and operational conditions. The results of the study are summarized as follows; (1) The cutting graph by the new cutter-bar system depends upon the magnitude of ratio of forward travel(Vm) to crank speed (R$\omega$); The cutting pitch for Vm/R$\omega$ 1 (whole cycle cutting) and Vm/R$\omega$=2/$\pi$ (a half cycle cutting) are 2$\pi$ Vm and 4R, respectively. (2) The experimental vibratory system had been proved to function adequately so that it can be used in determining the required counterweight to minimize the vibratory motion of cutter-bar. (3) Experimentally determined counterweight to give the least vibratory motion was a little greater than the theoretically determined one. With the optimum counterweight it was possible to reduce up to about 87% of the amplitude without counterweight, which may be considered to be within safe operational region. (4) To avoid the actual operation of the cutter-bar at resonance which occured in low frequency ratio, it was considered that the rotational speed of the crank for a specific design of mower should be determined separately in connection with the desired cutting graph.