To transfer torque and speed from a rotating power source to another device, a transmission system is usually required. The most common and widely used transmission system is the gearbox. Various types of gearboxes have been designed so as to meet various application demands. The need to minimize failure rates of gears during operation and further improve on the quality during the design process, gear dynamics have been established. Existing literature has already established that the main internal excitation source of gear dynamics relates to time-varying mesh stiffness. Therefore, accurate evaluation of gear mesh stiffness has been deemed crucial for gear dynamic analysis. Presently, experimental approaches for analyzing gear dynamics have show auspicious attributes. Unfortunately, no published experimental plan is easy to implement as they demand intricate measurement devices or complex mathematical derivations.
Dr. Xihui Liang (currently at University of Manitoba) and Prof. Ming J. Zuo at University of Alberta in collaboration with Dr. Hongsheng Zhang at Harbin Institute of Technology and Prof. Yong Qin at Beijing Jiaotong University developed three new models for spur gear mesh stiffness evaluation. They anticipated that the proposed models would be effective in dealing with involute spur gears with tooth profile modification in the absence of tooth damage. They used the finite element analysis to evaluate the mesh stiffness of standard involute spur gears. Their work is currently published in the research journal, Mechanical Systems and Signal Processing.
The research technique used by the scientist commenced with a thorough description of the proposed model 1 for gear mesh stiffness evaluation. Next, the researchers presented the proposed model 2 which was used to evaluate the gear mesh stiffness by using angular deflections at different circumferential angles of an end surface circle of the gear bore. They then proceeded to the proposed model 3 which required the angular deflection at an arbitrary circumferential angle of an end surface circle of the gear bore but could only be used for gears with the same tooth profile among all teeth of a gear. Lastly, the accuracy of the proposed models was evaluated using finite element analysis.
The authors observed that the proposed model 1 could cope with involute spur gears with tooth damage, like tooth crack and pitting. Additionally, they noted that the proposed model 3 could not deal with involute gears having tooth damage. Lastly, the researchers realized that the proposed model 2 had an unknown capability of dealing with tooth damage.
In summary, the study presented three novel models for evaluating time-varying gear mesh stiffness. Their main observation was that the proposed model 1 gave a very accurate mesh stiffness result when compared with other existing models, but with an underlying assumption of the gear bore surface being rigid. Furthermore, finite element analysis and comparisons demonstrated that proposed models 2 and 3 had potential to yield accurate result in gear mesh stiffness evaluation and that they were insensitive to gear bore size. Altogether, a comparison with the proposed model 1, the maximum error caused by the proposed models 2 or 3 was seen to be 3.3%, which was quite small.
Xihui Liang, Hongsheng Zhang, Ming J. Zuo, Yong Qin. Three new models for evaluation of standard involute spur gear mesh stiffness. Mechanical Systems and Signal Processing 101 (2018) page 424–434.Go To . Mechanical Systems and Signal Processing