Dynamic Analysis of Offset Printing Press Gear-Cylinder-Bearing System under Time-Varying Meshing Stiffness Effect

摘要

This study proposes a new nonlinear model for offset printing press gear-cylinder-bearing system by the lumped parameter approach. The multi-DOF model consists of helical gear pairs and spur gear pairs with time-varying meshing stiffness. Bearing and shaft flexibility are included in the model as well. The equations of motion are obtained by Darren Bell principle and Runge-Kutta numerical method is used to solve the motion equations. The results show that meshing stiffness and bearing stiffness significantly affect critical speed, vibration acceleration and meshing force. Multi-body dynamics software is applied to compare with lumped parameter model. The results show that there are many similarities in different aspects. Results of experimental study on the offset printing press are also presented for validation of different models. After the completion of the Discrete Fourier Transform, the graphics display that the peak frequencies of acceleration are an integer multiple of the gear meshing frequency. It demonstrates that mechanical vibration is mainly from gear transmission system at high speed and gear transmission system leads to nonlinear vibration. This work provides a foundation for further improvement of the dynamics of gear system.