The extremely poor loading performance of a thin coal shearer drum affects the mining efficiency in thin seam mining seriously on account of the restriction by the complicated mining environment and seam thickness. The coal loading performance of the drum is influenced by several complex factors, such as motion parameters and structural parameters, including the structure and form of the hub. The form of the drum hub is cylindrical in general, and in order to study the influence of the hub form on the coal loading rate of the drum, seven drums with different hub forms and structures were designed. The influence of the complexity of hub structures on the coal loading performance was studied by discrete element method (DEM) simulation in this paper. The change curves with the research object of different drums, such as coal loading rate, velocity field distribution, and contact force between fallen coal particles, were obtained. The results showed that the conical hub drum can improve the coal loading performance than the cylindrical hub drum, and the curve-shaped hub drum had a more obvious promotion on the coal loading performance. The coal loading rate increased first and then decreased with the increase of hub cone angle. Compared with the conical hub drum, the curve-shaped hub drum can not only improve the coal loading rate, but also has a larger space containing coal. This study has proposed a drum with a new form hub which could increase the coal loading rate, and the methods and conclusions provide the guidance for drum hub design.

The automatic height adjustment of a shearer cutting drum is a key technology for shearer automation. However, a fundamental and important requirement for underground electronic products is explosion-proof rating, which creates great challenges to the research on the control method of the shearer height adjustment system. To address this problem, a novel shearer height adjustment control method was proposed based on basic fuzzy control, and the feasibility of the height adjustment method was studied with the help of multisoftware cosimulation technology. First, the drum cutting coal model was established using Finite Element Method (FEM) software LS-DYNA, the mechanical model of the gear transmission system model and the height adjustment system were constructed with the multibody dynamics software ADAMS, the hydraulic height adjusting system model was constructed with AMESim, and a fuzzy controller for shearer height adjustment was developed in Simulink. Then, the data conversion interface between the mentioned models was constructed using MATLAB, to obtain the cosimulation model for the shearer automatic height adjustment. Finally, with the help of fuzzy control method, the feasibility of the cosimulation model used in the adaptive control method of the shearer drum height adjustment was verified. The results show that the cosimulation model can adequately describe the height adjustment process of a shearer, which lays a foundation for the optimization of adaptive height adjustment method. At the same time, the proposed model is also applicable for studying the dynamic characteristics of the mechanical-electrical-hydraulic coordination in the process of shearer adaptive height adjustment.

Continuous mining is one of the development goals for metal mines, and the application of coal mining equipment represented by shearers provides a reference for continuous mining. However, rock in metal mines is generally harder than coal, making cutting difficult. Improving the surrounding rock conditions is an important way to improve the applicability of the drum for hard rock cutting. Therefore, this article explores the correlation between drum-cutting performance and surrounding rock boundary conditions, aiming to obtain surrounding rock boundary conditions that can help improve drum-cutting performance. To achieve the goal, a model of a shearer drum and hard rock is established using finite element software. With the model, hard rock cutting was simulated and the stress distribution on rock mass, deformation of rock mass, and drum cutting force during the cutting process under different confining pressures were analyzed. Relations between drum cutting force and confining pressure on rock mass were obtained. Then, drum cutting force under different free surfaces of rock mass are studied and the positions of free surface on rock mass that help to reduce the drum cutting force were summarized. According to the research, when the rock mass is under uniaxial compression, drum cutting force increases with the confining pressure on the rock mass; In addition, the free surfaces on the rock mass are proved to be helpful to reduce the drum cutting force. The research content lays the foundation for the boundary conditions required to reduce drum-cutting force in metal mining.

Bauxite shearers frequently face challenges such as difficult drum traction, significant load fluctuations, and a short lifespan of conical picks during operation, all of which adversely affect equipment stability. To improve the reliability of the bauxite shearers, rock fragmentation tests were conducted using a servo press and a cutting test equipment. The finite element method is employed to simulate the working process of the drum in order to determine the forces acting on both the total drum and each individual conical pick. Additionally, a method aimed at reducing the force on the drum is proposed and simulated. The research results indicate that the traction resistance of the drum can be reduced and the stability of equipment operation can be increased by appropriately increasing the cutting distance of the vane conical picks, adopting a sequential conical picks arrangement method, and retracting the end plate conical picks.