Influence of Pressure Angle on the Dynamic Characteristics of Asymmetric Helical Gear Transmissions

Abstract

To address the lack of research on the dynamic characteristics of asymmetric helical gears, this study systematically investigates their time-varying meshing stiffness and meshing impact characteristics based on the lumped-parameter method and nonlinear dynamic theory. An eight-degree-of-freedom dimensionless dynamic model is developed. Using the pressure angle on the driving side as the main variable, the dynamic characteristics of asymmetric and symmetric helical gears are compared, and the effects of different pressure angles on time-varying meshing stiffness, time histories, phase portraits, and Poincaré maps are analyzed. The results show that the asymmetric helical gear exhibits higher average meshing stiffness, smaller vibration amplitudes, and smoother responses than the symmetric gear. Within a driving-side pressure angle range of 30 to 35 degrees, the system achieves the best stability and periodicity, and the meshing impact amplitude is effectively suppressed. However, excessively small or large pressure angles lead to reduced system stability. This work clarifies the dynamic behavior of asymmetric helical gears and provides a theoretical basis for parameter design and high-performance transmission optimization.