Threshing Mechanism of Dual Flat Belt for Rice Harvester (Part 1)

Friction between Rice Grains and Rubber Surfaces

Abstract

A friction experiment was conducted to determine the coefficient of friction between grains of four rice varieties and three types of rubber sheet surfaces. The rice varieties used in the experiment were Arborio (Javanica type), Bluebonnet 50, Jhona 349 (Indica type), and Koshihikari (Japonica type). The rubber sheet surfaces were a conveyor rubber belt (Neoflexstart-V), a natural rubber sheet and a silicon rubber sheet. The coefficient of friction of each grain tested was significantly different when it was threshed between different rubber surfaces. The exception was the coefficient of friction between Arborio and the Neoflexstart-V and the natural rubber sheet, which were similar. The coefficient of friction between the Neoflexstart-V conveyor rubber belt surface and the rice grains showed a tendency to increase with increasing grain moisture content. The coefficient of friction determined in this experiment will be used in a numerical simulation to predict the torque requirement of a new dual flat belt threshing method for rice harvester. This new method should be appropriate for threshing high shattering rice.