The synchronous box type shaker is the power source of the mining linear vibrating screen. The helical gear pair is a key component of the box type shaker, which plays an important role in generating excitation force through synchronous transmission of the main and driven shafts of the shaker. Due to the various internal and external excitation effects on the helical gear of the shaker, such as the elastic support of the screen body spring seat, large eccentric blocks, tooth side clearance, and large bearing clearance, the working conditions are harsh and fatigue damage is extremely easy to occur, Causing fatigue cracks and fractures in the helical gear of the exciter, which affects the smoothness and reliability of the transmission. At present, in the research of helical gear transmission based on rotating machinery, domestic and foreign scholars usually use center distance as an internal excitation to study its impact on the dynamic characteristics of helical gears, and conclude that the center distance of helical gears directly affects the meshing stiffness and meshing overlap of helical gears. However, there is still limited research on the impact of the center distance variation of vibrating screens (vibrating machinery) on the meshing impact of helical gears.
ZHY Gear’s research mainly involves the following content:
① A virtual prototype model accurately reflecting the dynamic characteristics of the helical gear of the exciter was established using ADAMS software by comprehensively applying relevant knowledge from courses such as “Mechanical Principles”, “Mechanical Design”, and “Mechanical Drawing”, and the correctness of the model was verified;
② Four special operating points were determined based on the fluctuation law of the actual center distance of the helical gear pair. On this basis, the dangerous operating points of the helical gear pair were determined. Through the fatigue life analysis of the helical gear pair under standard and non-standard center distances, it was found that non-standard center distances not only ensure the screening motion trajectory required by the exciter, but also greatly improve its fatigue life;
③ Through the analysis of the dynamic characteristics of helical gears under non-standard center distance, it is found that non-standard center distance reduces the fluctuation intensity and amplitude of center distance, weakens meshing impact, and can make meshing transmission more stable.
Through the case training of this simulation experiment and scientific research practice linkage, not only can it promote students to digest and absorb multidisciplinary knowledge and build a complete professional knowledge system, but it can also enhance their comprehensive practical ability and engineering innovation ability, which meets the requirements of “new engineering” to comprehensively enhance students’ ability to solve complex engineering problems. In addition, this case further enriches the form of experimental teaching with lower implementation costs and stimulates students’ interest in learning.
The main conclusions of the study are as follows:
(1) ZHY Gear has established a reliable virtual prototype dynamic model of the mining vibrating screen excitation system. Through simulation, it was found that the main reason for the sharp increase in stress on the helical gear was the squeezing of teeth caused by the periodic fluctuation of the center distance. The eccentric block deviation angle of 0 ° was determined as the dangerous working point of the exciter gear, and it was verified that the fatigue life of the helical gear at this point did not meet the requirements.
(2) The method of increasing the installation center distance of helical gears can alleviate the squeezing phenomenon of helical gears, while ensuring the working trajectory and fatigue life requirements while taking into account the tooth side clearance.
(3) The dynamic response analysis shows that after using this method, the fluctuation of meshing force decreases, the time-frequency components of acceleration signal and normal meshing force are simpler, and the meshing process of helical gears is smoother. This proves the rationality of the method of improving the meshing transmission performance of the vibrating screen exciter helical gear pair by changing the installation center distance.