To address high cleaning losses caused by high impurity content and uneven distribution during rapeseed threshing, this study proposes a drum pneumatic-assisted threshing and separation method. Initially, by determining the suspension velocity characteristics of various threshed components, auxiliary blades were designed and integrated to construct a non-uniform gradient airflow field, generating a directional pneumatic transport effect. CFD simulations confirmed that this configuration induces a stable axial spiral airflow. Driven dynamically by this airflow, miscellaneous materials are guided to migrate orderly toward the rear of the concave screen, enabling active source-based regulation of the spatial-temporal flow behavior and component distribution. Multi-parameter correlation analysis indicated a significant negative correlation (coefficient = –0.88) between axial airflow and the average impurity ratio. Field experiments demonstrated that at a feed rate of 2.8 kg/s with auxiliary blades, the grain loss rate was reduced to 3.7%, compared with 6.3% without auxiliary blades, corresponding to a 41.3% reduction. This research demonstrates that axial airflow can effectively regulate threshed material at the source, providing a novel approach for high-efficiency and low-loss threshing and cleaning.

Soil is the foundation of agriculture. Reducing soil damage by walking mechanism is an inevitable requirement for modern agricultural equipment and an important way to achieve sustainable agriculture. In this paper, the problem of mechanical damage to soil by tracked agricultural equipment was analyzed. The current status and development presented in three aspects: the influence of external load on the soil, the relationship between tracked walking mechanism and ground load distribution, and the design and optimization method of agricultural tracked walking mechanism. Based on the systematic summary and analysis of the research trends, grounding load influencing elements of tracked walking mechanism and the technical difficulties of walking mechanism of tracked agricultural equipment designed for soil conservation are pointed out. The investigation of soil microstructure and macroscopic physical property change law under external load, the research of load distribution law and regulation method of tracked walking mechanism, the optimization design of tracked walking mechanism are the keys to reduce the soil mechanical damage.