Problems in dynamic research of multi stage gears in shearer cutting section

Based on the multi-body dynamics commercial software ADAMS simulation platform and considering the dynamic characteristics of the rocker box and transmission system, some scholars established the rigid flexible coupling model of the cutting part. Lian Zisheng et al. Compared the stress response of the hinge joint between the rocker arm and the body of the shearer when the rocker arm box is regarded as a rigid body and a flexible body respectively. Zhao Lijuan and Ma Yongzhi analyzed the dynamic deformation of the planetary carrier and rocker box of the cutting part in the process of coal cutting, and considered that the deformation was too large and the stiffness was insufficient. Guo Huizhen simulated the vibration characteristics of the rocker box under different working conditions, analyzed the influence of the transmission system on the vibration of the rocker box, and provided the basis for the fault diagnosis of the cutting gear. In addition, Zhao Lijuan and Tian Zhen established the rigid flexible coupling model of the whole shearer, and analyzed the influence of the vibration generated in the process of coal cutting on the electric control system and hydraulic system of the shearer. Zhao Lijuan and LAN Jinbao carried out the finite element analysis of the first pair of high-speed gears in the transmission system of the cutting unit. Based on the RecurDyn simulation platform, the contact stress in the process of gear meshing under the support of flexible box was simulated. The above research has carried on the preliminary research to the rocker box deformation and its related influence, but it is not deep and systematic enough, especially the lack of revealing the coupling mechanism between the transmission system and the rocker box.

To sum up, there are some problems in the research of gear dynamics of shearer cutting part

① There is over simplification in modeling. A large number of studies ignore the influence of rocker box deformation on the transmission system. Although some studies establish the rigid flexible coupling dynamic model of the cutting part, they simplify the transmission system too much, and do not reflect the structural characteristics of multi-stage gear transmission with flexible support of the cutting part.

② The analysis is not systematic enough. Although some researches have analyzed the influence of rocker box deformation on gear contact stress of transmission system, the dynamic coupling characteristics of transmission system and rocker box can not be fully revealed without analyzing the influence on dynamic load, acceleration, etc., and without considering the influence of working condition change on simulation results.

③ The methods used in design are relatively backward. Some researches reduce the dynamic load of the cutting transmission system by motor control, but the research on improving the dynamic performance of the cutting transmission system from the perspective of mechanical design is rare. The common way is to design the cutting gear system by using the general strength checking formula in the mechanical design manual, which is lack of pertinence.