Design And Error Analysis Of Precision Planetary Drive For Aircraft Actuator

Electrical mechanical actuator is an actuating device developed rapidly in recent years which is important to ensure the flight quality.It is responsible for controlling the deflection of the rudder according to the instructions of the operating system in the flight control system,so as to adjust the flight attitude and trajectory of the aero-vehicle.With the rapid development of the aviation industry,the performance requirements of actuators in the harsh working environment are also improving.The gear transmission device is the core part of the power transmission of electrical mechanical actuator and its carrying capacity,precision and transmission ratio and other technical parameters directly affect the performance of the device.In this paper,the design and transmission precision of the compound planetary transmission device used in electrical mechanical actuators are studied.According to the working environment of electrical mechanical actuator,this paper presents a planetary gear transmission device which can realize small size,large torque,large transmission ratio,small error and high precision.Through a variety of planetary gear mechanism comparison,this paper adopts an improved scheme of 3K gear train and completes the structural design of the compound planetary transmission device.In order to meet the requirement of small backlash,the clearance elimination mechanism is designed according to the structural characteristics of the device.The gear matching calculation,efficiency analysis and strength check of the planetary transmission device are carried out to provide theoretical basis for the design of the device to complete the design of the specific structure of the device.Aiming at the two important indexes,backlash and the transmission error,which affect the transmission performance of the gear device,this paper puts forward analysis method,which is used to evaluate the rationality of the design.Based on the principle of error statistics and the method of probability theory,a model for backlash analysis of compound planetary gear transmission is presented.The main error sources of gear mechanism are analyzed in this model,including the inherent error of dear,device error and deformation error.The influence of each single error on the backlash of compound planetary transmission is analyzed,and the mathematical relationship between error and gear error is established.According to the error distribution rule,the probability method is applied to obtain the backlash probability analysis model of the transmission device.Based on the theory of statics,the transmission error model of the device is established.According to the meshing principle of gear,each error of compound planetary gear device is converted into the equivalent meshing error on the meshing line.The relative displacement relationship with errors among the components of the device is derived and the transmission error model of the device is obtained by using the static method.The main factors affecting the precision of the gear transmission are determined,and the direction and emphasis of improving the precision are clarified.According to these,how to improve the transmission precision of planetary gear transmission device in gear parameter selection,structure design,key parts selection and other aspects in the process of gear design is put forward.