Functional Studies of Combine (Part 2, 3)

Characteristics of the Fluctuating Torques of the Combine Flements and the Ground Contact Pressure Distribution of its Track

Abstract

We measured the torques at each element of the full tracked combine and contact pressure under its track. In this paper, we discussed the characteristics of the torque at the threshing device, average power requirements for threshing, contact pressure distribution and fluctuation of the torque at the travelling counter shaft.
1) The ranges of the fluctuations of the cylinder torque were wide and their frequency distributions were almost normal when the feed rates were low. It is noteworthy in the case of designing the cylinder shaft that the maximum torques amounted to six times as much as the mode at the high feed rate.
2) The fluctuation of the clyinder torque seems to be caused by the free vibration of the cylinder torque, the complex system for power transmission in the combine and the complicated external forces through threshing.
3) Although at the light load the force acted on a concave was fluctuated by the threshing tooth on the cylinder and concave, at the heavy load the frequency of the fluctuation redued to half of the fluctuation at the light load.
This phenomenon seems to show that threshing as well as cuttingand pressing of straws are carried out at the firstrow of the concave tooth in the case of the light load, but at the heavy load the flow of rice fed to the threshing device changed.
4) The contact pressure distribution pattern under the full tracked combine was never uniform. The maximum pressure was observed under the fore of the track contacted with soil, and amounted to six times as much as the average.
5) The torque of the travelling counter shaft fluctuated periodically with pitching of the combine which was caused by the reciprocating motion of the straw rack.