Variation and Modal Characteristic of Tangential Threshing Cylinder Undergoing Threshing Dynamics

Abstract

During the rice-threshing process, straws always attached to a threshing cylinder and induced vibration and modal variation. In this paper, the constraint and threshing modals of the threshing cylinder were tested under idling and load conditions, and the causes of vibration and modal variation were explained. Based on the constraint and modal of the threshing cylinder, the vibration amplitudes and frequencies undergoing rice threshing were tested and analyzed. Results showed that mass of straws decreased gradually with the separation of rice grains and straws. And there was a nonuniform change in the circumferential resistance of the threshing cylinder. The fluctuating torque, speed, and frequencies during threshing process would cause vibration of the threshing cylinder. During rice-threshing process, the other natural frequencies were greater than the excitation frequency. With the accumulation of a large amount of straws, the threshing modal frequencies of the tangential threshing cylinder increased. The threshing bars caused vibration of the tangential threshing cylinder in the left and right direction mainly at two frequencies. At idling state of no-load, the vibration frequency 42.97 Hz of the tangential threshing cylinder in X direction was close to the constraint modal frequency 41.58 Hz. The eccentric load caused the excitation frequency to increase during the rice-threshing process. The vibration frequency was also closely related to the threshing modal. The tangential threshing cylinder with low vibration characteristics could be designed by using the eccentric vibration characteristics during the threshing process.

Structure design and rice threshing performance of the variable-speed inertial pulley for simulating artificial threshing

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“…With the development of science and technology and the gradual improvement of mechanization, rice harvesting has basically achieved full mechanization [1]. e crawler rice combine harvester is a complex large-scale agricultural harvesting machine that integrates mechanical functions such as harvesting, threshing, separation, and sorting [2][3][4]. During the field harvesting operation in complex working conditions, the vibration characteristics of the chassis frame under the excitation of multiple sources are complex and changeable, which will affect the reliability and operation safety of the whole machine field harvesting [5][6][7].…”

Vibration Transmission Characteristics and Detection Method of Bilateral Chain Drive of Multicylinders

“…e meshing effect of the transmission chain often has a large impact force and lateral vibration. In addition, due to the polygon effect of the chain transmission, the chain transmission has an uneven working speed [7].…”