DESIGN AND EXPERIMENT OF SEGMENTABLE ADJUSTABLE THRESHING DEVICE FOR RICE SEED BREEDING

In response to the current challenges in the harvesting process of hybrid rice, where the threshing gap cannot adequately adapt to the varying threshing requirements, leading to high grain breakage rates, loss rates, and frequent clogging of the drum, a new threshing device for hybrid rice was designed by adjusting the gap of the concave screen. The concave screen was divided into a low-loss threshing section and a low-damage threshing section, with the addition of a hydraulic system to enable the adjustment of the threshing gap. A dynamic analysis of the rice at the spiral feeding inlet and within the threshing drum was conducted, determining that the adjustable range of the threshing gap is between 10 and 20 mm. A prototype of the low-loss threshing device for hybrid rice was built, and bench tests were performed with feed rate, drum speed, and threshing gap as influencing factors, while cleaning rate and breakage rate were used as response indicators in an orthogonal experiment to determine the optimal parameter combination. The optimal threshing performance was achieved at a threshing gap of 14.19 mm, a drum speed of 460.12 r/min, and a feed rate of 2.13 kg/s, resulting in a cleaning rate of 97.67% and a breakage rate of 0.295%. Subsequent verification tests under the optimal combination showed a cleaning rate of 96.2% and a breakage rate of 0.36%, meeting the harvesting standards for hybrid rice. This research provides theoretical support for the development of mechanized harvesting equipment for hybrid rice.