Design and Parameter Optimization of Variable Speed Reel for Oilseed Rape Combine Harvester

Abstract

A variable speed anti-tangling reel mechanism was designed to address the problems of tangling, hanging and rewinding of the tassel wheel and the high paddling loss in the current Chinese rape combine harvester cutting table. The kinematic equations of the reel mechanism were developed, and the analysis showed that the speed in the entry stage is low and the speed in the exit stage is high, and the attitude of the reel teeth change with the rape plant movement during the whole paddling process. A single-factor test and a multi-factor regression orthogonal combination test were carried out using the cutting table loss rate of rape harvesting as the evaluation index. The main and secondary factors affecting the cutting table loss of the variable speed reel were obtained as the reel input speed, the machine travel speed and the ground angle of the frame. The optimal range of the input speed of the reel is from 25 r·min−1 to 31 r·min−1, the optimal range of the forward speed of the implement is 0.8 m·s−1~1 m·s−1, and the optimal range of the rack level angle is from −10°to 10°. A mathematical model of regression of cutter loss and the main influencing factors was established, with the coefficient of determination R2 = 0.9918, the relative error between the test value and the optimised value of the regression equation was 5.36%. The optimal combination of parameters for the variable speed reel was obtained with the lowest cutting table loss rate in rape harvesting as the optimization target: reel input speed 25 r·min−1, frame parallel to the ground and implement travel speed 0.7 m·s−1. Field validation tests and comparative tests of cutting table loss of the two reels were carried out. The test results show that the regression mathematical model of the cutting table loss is more accurate, and the cutting table loss is reduced by 13.9% with the variable speed reel compared to the cam-action reel, and there are no problems with the paddle teeth hanging and tangling during the paddling process.