A comprehensive mesh stiffness model for spur gear considering coupling effective of thermo-elastohydrodynamic lubrication

Thermal elastohydrodynamic lubrication (TEHL) plays a crucial role in meshing stiffness, friction, wear, vibration, and transmission stability during the gear meshing. Based on the TEHL and Blok theories, a comprehensive meshing stiffness model of spur gear is proposed by combining thermal stiffness, oil film stiffness, and time-varying meshing stiffness, which is closer to the actual working conditions compared with conventional method. The influences of torque, rotational speed, and module on the lubrication performance and meshing characteristics are investigated, and the distributions of oil film pressure, film thickness, tooth surface temperature rise, friction coefficient, and stiffness are obtained. The results reveal that a light torque, large rotational speed, and module can improve loading capacity and lubrication performance, but excessive parameters will increase tooth surface temperature rise and thermal deformation, and reinforce meshing impact, which further increase the tooth surface wear or bonding. Therefore, it can be concluded that the reasonable parameter match is valid in improving gear lubrication characteristics, mitigating meshing impact and improving gear meshing characteristics, and further enhance system stability.