Nonlinear dynamic model of yaw-torsion coupling was established for involute spur fixed-shaft gear drive and planetary gear drive respectively, and a non-linear dynamic engagement model was put forward. Vibration characteristics test and model verification were carried out for two-stage fixed-shaft gear drive and single-stage planetary gear drive respectively. Single-stage gear drive was analyzed based on yaw-torsion coupling non-linear dynamic model.Dynamic and non-linear dynamic characteristics of stage gear drive system under steady-state and no-load conditions; for single-stage gear drive system, the influence of profile modification parameters on static and dynamic characteristics is analyzed, and the optimal design of profile modification is carried out; for tracked vehicle gear drive system, the dynamic characteristics of gear drive system under gears are systematically analyzed and established.An optimization model considering the dynamic characteristics of each gear is developed and the optimization design is carried out.The main research results and conclusions are as follows:
(10) Viewed from the influence of tooth profile modification on the strength of teeth, the strength of teeth at different engagement positions is greatly affected by tooth profile modification. The strength of teeth in the middle of single-tooth engagement area and double-tooth engagement area decreases for SHORT-TOOTH modification, while that in other engagement positions increases; while the strength of teeth in long-tooth modification decreases only near the top of the teeth.With the increase of modification quantity or the decrease of modification length, the strength of the teeth in the single-tooth meshing area gradually decreases.
(11) The two gears have the same modification type. When any two modification parameters change, the dynamic load coefficient has a global optimum.In order to reduce dynamic load coefficient, an optimization model of tooth profile modification based on the nonlinear dynamic model of the yaw-torsion coupling of involute spur gear drive system was established, and several tooth profile modification parameters were optimized, which effectively reduced the dynamic load of gear drive system and provided theoretical basis for the design of low-vibration and low-noise gear drive system.
(12) For tracked vehicle gear drive system, with the increase of gears, the dynamic engagement force maximum of loaded gear, dynamic engagement force maximum of unloaded gear and root mean square value of unloaded gear, and maximum dynamic stress of each shafting all show a decreasing trend as a whole; the dynamic load coefficient of gear drive system under high gears is larger, and the vibration characteristics are more obvious; the planetary gear drive rotates as a whole;The bearing and drive shaft supporting the planetary drive have small dynamic loads, but the bearing and drive shaft supporting the fixed drive have large dynamic loads.Improving the gear machining accuracy level has little influence on the dynamic load of gear drive system in low gear, but can significantly reduce the dynamic load of gear drive system in high gear.
(13) Based on the non-linear dynamic model of gear transmission system of tracked vehicle, an optimization model was established which comprehensively considers the dynamic characteristics of each gear.The optimization results effectively reduce the dynamic load of the gear drive system, which indicates the feasibility of the optimization model and provides a reference for improving the dynamic performance of the gear drive system of tracked vehicles.
