Research On The Tail Rotor Bearing Teating Machine And The Dynamic Characteristic Analysis

The main role of the helicopter tail rotor is to form the yaw moment to counteract the reverse torque of the main rotor,and self-lubricating spherical plain bearings are widely used in the tail rotor systems due to their strong bearing capacity and strong impact resistance.The self-lubricating spherical plain bearings are the key parts installed in both ends of the four variable pitch rods on the helicopter tail rotor system,and the movement difference between the adjacent two variable pitch rods is 90 °.The resulting interaction sometimes leads to failure of a spherical plain bearing that does not meet its rated life.Therefore,the developed spherical plain bearing testing machine should simulate the actual structure of the helicopter tail rotor system and motion conditions of the spherical plain bearing as much as possible to study the bearing friction and wear properties,so as to provide reliable test data for theoretical calculation and practical application.Besides,it is of great significance to improve the reliability and safety of the tail rotor system.According to the actual working conditions,design the tail rotor self-lubricating spherical plain bearing testing machine.The main working principle of this testing machine is used on the helicopter tail rotor are installed on the experimental machine to simulate the actual working conditions,which is used to test and evaluate the comprehensive service life of the bearings.The main simulation of the spherical plain bearing is the tilt swing,rotary motion and compound movement.The finite element simulation of the swing system of the testing machine is carried out.The dynamic models of the relevant parts and components are analyzed by using the solid analyzing software ANSYS.The dynamic characteristics of the key components are analyzed,including the modal analysis and the transient response analysis.The dynamic characteristics and unbalanced response of the testing machine are obtained,which lays the foundation for further optimization of the testing machine.The dynamic balancing of the eccentric shaft is carried out.In order to reduce the vibrations caused by the imbalance of the eccentric shafts,based on the rotor dynamics and finite element numerical analysis method,the amount of vibration on the selected measuring points is minimized according to the influence coefficient balance method to realize the dynamic balance of the eccentric shaft.The unbalanced vibration amplitude of the eccentric shaft can be reduced to a great extent by dynamic balancing,thereby reducing the vibration of the machine caused by unbalanced mass.Test the vibration of the test machine.In order to verify the accuracy of dynamic balance,the vibration acceleration data of the corresponding measuring point are obtained by experiment.The amount of vibration displacement is obtained by numerical integration method.The experimental results are compared with the simulation results to improve the reliability of simulation and test results.