Design and experiments of the reel board header device for an oil sunflower harvester

Oil sunflower has widely been served as the characteristic nutritional quality of the vegetable oil industry in Xinjiang Uygur Autonomous Region, China. The planting area of oil sunflower is ever-increasing in recent years, particularly with the adjustment of agricultural industrial structure. Nevertheless, the low level of mechanized harvesting has posed a great challenge to the continuous expansion of planting areas in the rapid development of the oil sunflower industry. The current harvester of oil sunflower is using the wheat combine harvester with the modified cutting table in Xinjiang, where the threshing device and cutting table are not suitable for oil sunflower harvesting. The cutting table device in the machine cannot meet the harvesting requirements of high efficiency and low damage, according to the grain damage rate and loss rate of oil sunflower in the harvest. Structural parameters of oil sunflower rare also significantly different between the varieties and planting modes, such as the thickness and diameter of the faceplate, as well as the diameter and height of the stem. Therefore, it has become an urgent problem to realize mechanized harvesting with high efficiency, low damage, and low loss for the oil sunflower industry. In this study, a specific reel-board cutting table device in a combine harvester was proposed for the mechanized harvesting of oil sunflower, with emphasis on the low loss or damage of grains and reliable operation with high efficiency in harvesting. The structure and working principle of the cutting table devices were also introduced to the special use for the oil sunflower. A movement model of dialing teeth was established to analyze the dynamic characteristics and the movement track for the end point of dialing teeth in the cutting table device. An investigation was made to clarify the changing relationship among the rotational speed of the reel board, the forward speed of the machine, and the circumference of the reel board, in the simulation for the end movement track of the reel board. A MATLAB software was used to write the program and implement simulation, in order to obtain the motion trajectory curve of two adjacent dialing teeth. The performance test results show that the loss rate of oil sunflower was 2.04% in the cutting table disk, where the tilt angle of the guide plate was 25°, the speed of the screw conveyor was 150 r/min, and the distance between the reel board and the guide plate was 170mm. An orthogonal experiment and parameter optimization of field oil sunflower harvesting were utilized to explore the effect of the different combinations of operational parameters, such as the forward speed, the rotation speed of reel board, and the height of the stalk stub, on the loss rate and damage rate of oil sunflower seeds. A Design-Expert system was used to optimize the test data, thereby obtaining the optimal combination of parameters. The experimental optimization results show that the loss rate and damage rate of oil sunflower were 1.90% and 0.65%, respectively, where the forward speed of the oil sunflower harvester was 1.2 m/s, the rotation speed of the reel board was 240 r/min, and the height of the stalk stub was 570 mm. The findings can significantly improve the performance of a combine harvester, particularly on structural design and parameters optimization in a combine harvester for the oil sunflower.