Dynamic Characteristic Research On On-Off Mechanism Of Offset Machine

The on-off mechanism has an important function to the printing machine, the quality of which concerns the working performance of the printing machine and the quality of printed products directly. The sheet-fed offset-press both at home and abroad mostly adopts the mechanical on-off mechanism. The higher printing speed is, the heavier the impaction leaded by on-off cam becomes, which will transmit to printing cylinder and affect the quality of presswork. Kinematics and dynamics analysis of on-off mechanism are carried out mainly, and a hydraulic shock absorber is designed to reduce the vibration and impaction leaded by on-off mechanism.The main woks are as following:1. Vector radial coordinates method is used to analyse the movement of on-off mechanism and to calculate the displacement, speed and acceleration of rubber cylinder's center during impressing-on and impressing-off.2. Pro/E software is used to set up the tridimensional model of on-off mechanism and carry on kinematics and dynamics analysis to realize the movement simulation during impressing-on and impressing-off which proves the result of theory analyses and offers the basis for confirming the parameter of hydraulic shock absorber.3. According to the result of kinematics and dynamics analysis hydraulic shock absorber is outfitted for on-off mechanism. The parameter of hydraulic shock absorber is confirmed according to the inside structure of the existing hydraulic shock absorber, and theoretical analysis of the other characteristic of the hydraulic shock absorber is made. The results indicate that hydraulic shock absorber can satisfied the request of on-off mechanism working performance.4. Pro/E software is used to carry on dynamics analysis for on-off mechanism with hydraulic shock absorber. The influence of hydraulic shock absorber to the stability of on-off mechanism movement is analyzed. The simulation results indicate that hydraulic shock absorber has very good function for reducing the vibration, impact and abrasion among the components of on-off mechanism.From the practical request of producing, a hydraulic shock absorber is outfitted for on-off mechanism, which reduces the vibration, impaction of the on-off mechanism, and makes its movement more steadily, more reliably. Thus the quality of the printed matter is improved. This work can improve design level of homemade press machine, and reduce the gap between internal press machine and external top grade ones.