Dynamic modeling and analysis of vibrating screen for vibration isolation of air spring with auxiliary chamber

The air spring with auxiliary chamber has throttle element between two chambers,which can absorb vibra- tion energy and has good damping characteristics. As a new type of vibration isolation element,the air spring with aux- iliary chamber can shorten the time of vibrating screen passing through the resonance area,reduce the resonance am- plitude and additional tilting motion,and improve the smoothness of vibration screen operation. By analyzing the two- degree-of-freedom (DOF) dynamic model of the vibrating screen and solving the kinematic differential equation,it is found that the vibration direction angle of the vibrating screen is not equal to the direction angle of the exciting force. The amplitude and throwing index can be represented by the single DOF model. Based on the theory of thermodynam- ics and fluid mechanics,a linear model of the air spring with auxiliary chamber was established,and the expressions of stiffness and damping were obtained. Then,the dynamic model of vibration screen based on the air spring with auxilia- ry chamber was deduced,and the kinematic differential equation was established. The vibration isolation system of air spring with auxiliary chamber and vibration test prototype was built to test the kinematics parameters of the prototype. The dynamic model was implemented in MATLAB / Simulink,and compared with the test results of the experimental prototype. The results show the accuracy of the model,i. e. ,the simulation amplitude of the model is 5. 321 mm,and the steady-state amplitude of the experimental prototype is 5. 372 mm,and the error is only 1% . The simulation results show that the motor speed has a small impact on the amplitude and a large impact on the throwing index. When the motor speed increases from 840 r / min to 990 r / min,the amplitude decreases from 4. 549 mm to 4. 427 mm,and the throwing index rises from 3. 6 to 4. 9. The amplitude can be adjusted by changing the initial pressure of the vibration i- solation system. When the initial pressure increases from 0. 1 MPa to 0. 6 MPa, the amplitude increases from 4. 446 mm to 6. 159 mm. The effect of orifice diameter on amplitude is not obvious. When the diameter of orifice in- creases from 2 mm to 20 mm,the amplitude changes from 4. 443 mm to 4. 467 mm. By changing the motor speed and the initial air pressure combination of the vibration isolation system,the amplitude of the test bed can be changed with- in 4. 45-6. 16 mm and the throwing index within 3. 46-6. 16,so as to adjust the vibrating screen.