The design of gear system is not limited to the static strength check, but the important content is to consider the dynamic performance of the system, including dynamic load coefficient, vibration intensity, vibration noise, critical speed and impact response. The main purpose of dynamic performance optimization of gear system is to make it run smoothly and ensure the reliability and durability of the system. The research status of dynamic performance optimization of gear system is summarized from two aspects of box structure optimization and gear modification.
The box body provides the installation base for the bearing, gear shaft and other components of the gear system. The weight of the box body accounts for a relatively high proportion in the whole gear system, and the box body is also the key component of the radiated noise. Therefore, the optimization of the box structure is of great significance to improve the dynamic performance of the gear system. Guo Neng et al carried out topology optimization for heavy vehicle transmission case with weight reduction as the goal, and compared and analyzed the dynamics and strength characteristics of the case before and after optimization. Min Haitao et al. Established the structural stiffness analysis process based on dynamic load by means of finite element analysis and modal test, aiming at the lightweight of automobile transmission. By using topology optimization, the weight of the box was reduced by 8%, the stiffness was unchanged, and the strength change was less than 5%. Yuan Shilin et al. Obtained the modal frequency of a double clutch transmission box by using modal analysis technology, compared and matched the excitation frequency of the engine, and carried out the lightweight design of the box on the premise of ensuring the structural strength. Liang Mingxuan also uses a similar method, taking the strength of a transmission case as the constraint condition, and uses topology optimization to carry out lightweight design. In addition, Wang Liansheng and Wei Chao optimize the box structure to reduce the radiation noise and enhance the impact resistance of the box.
Gear modification is an important means to improve the bearing capacity and prolong the service life of gear. In the past, people always strive to improve the gear machining accuracy, making it as close to the theoretical tooth profile as possible along the tooth profile, and as straight as possible along the tooth width. But the experiment, analysis and production practice show that the gear teeth that meet the theoretical tooth profile can not meet the requirements under the condition of high speed and heavy load. The basic starting point of gear modification is to make the pressure distribution on the tooth surface uniform as far as possible after the gear is loaded and deformed, and to reduce the eccentric load and the impact of meshing in and out. There are many kinds of gear modification technology, but generally speaking, there are two kinds of tooth profile modification and tooth direction modification.