In order to reduce the size of the threshing machine and improve its versatility, a vertical threshing device with a conical outer cylinder and an axial flow threshing drum was designed to ensure the quality of threshing while controlling the size of the threshing device. The structure and working principle of the vertical threshing device were expounded, and the stress on the threshing element during the threshing process was analyzed. An archtoothed threshing element was designed, and the force of the contact between the ear and the bow teeth was simulated and analyzed using EDEM software. The optimal diameter of the bow teeth was determined to be 10 mm. The roller speed, threshing gap, and bending radius of arch teeth were used as test factors, and the grain breakage rate was used as the test index. The results showed that the grain breakage rate increased with the increase of drum speed, decreased with the increase of threshing clearance, and decreased with the increase of the bending radius of arch teeth. The roller speed and threshing clearance had a significant effect on the grain breakage rate of the vertical threshing device. Finally, the optimal drum speed of the vertical threshing device was selected as 300 r/min, the threshing gap was 80 mm, the bending radius of bow teeth was 20 mm, and the grain breakage rate was 4.67%, which meets the requirements of national standards. This study provides a new idea for developing a new type of corn threshing device.

Aiming at the problems of missed seeding in the process of corn sowing, a mechanical missing seeding detection and reseeding device was studied by using the redundancy design method. The seed filling of the main seed metering device was continuously detected through the spanning seed probe rod, and the locking rod was driven to lock and unlock the reseeding device, so as to realize reseeding. A new type of seed probe rod structure was designed, adopting the doubledeck structure of the seed probe rod, to improve the precision of missed seeding detection. Optimizing the structural parameters of the detection device to realize the quick locking and unlocking of the reseeding device. Through the motion analysis of the reseeding device, the structural parameters of the reseeding device and the conditions for synchronous reseeding were determined to improve the seeding quality. Combined with the theoretical analysis, the single factor test and orthogonal test were carried out with speed of advance, seed exploration angle, and the maximum force of the reseeding return spring as the test factors, and the missed seeding index and qualified index as the performance indicators. The optimal parameter combination was determined as follows: the speed of advance was 0.9 m/s, the seed exploration angle was 45°, and the maximum force of the reseeding return spring was 12 N. Under this condition, the missed seeding index was 3.4%, and the qualified index was 94.5%, which could conform to the relevant national standards.

In order to solve the problem that corn straw bales tend to fall apart during collection and handling, we started from the analysis of the forces on corn straw bales and studied the changes of the load during bale resting, shifting, and deformation, as well as the factors affecting the stability of bales. The optimum combination of bale density of 175 kg/m ³, straw bale length of 88 cm, number of bale cords of 3, and bale drop resistance of 93.5% was determined through response surface analysis. The bale stability fully meets the production requirements and provides theoretical guidance for the research of the square straw bale baler.