Research And Realization Of Measuring Method Of Bearing Friction Torque Under Gravity And Microgravity

Bearing,as an important part of mechanical structure,is widely used in equipment in aerospace and other fields.Bearing friction moment has an important influence on bearing working life and accuracy.Therefore,it is very important to study bearing friction moment under gravity and microgravity.In this paper,a method for measuring bearing friction moment under gravity and microgravity is proposed and experimental equipment is developed.The relationship between bearing friction moment under gravity and microgravity and load size and speed as well as their mapping relationship are studied.The main research contents are as follows:Firstly,based on similarity theory and gravity balance principle,a method to measure bearing friction moment under gravity and microgravity is proposed.Similarity criteria and restraint relationship between experimental model and original model are established,and the feasibility that experimental model can solve a class of space problems is demonstrated.The load forms of any plain bearing with single crank rotary motion mode mechanism in space under gravity and microgravity are analyzed,and the measuring principle of bearing friction moment of plain bearing under different loads is analyzed.Secondly,based on the proposed measuring principle,the measuring device is designed and its main structure and gravity compensation device are optimized.In addition,the drive system and sensing detection system of the measuring device are selected as components,the software and hardware system of the measuring device is built based on Qt and industrial control equipment,the error source is found after experimental analysis,and finally the measuring device is optimized and analyzed,the improved parts are reworked,installed and debugged.Then,the output torque of theoretical system of bearing friction measuring device is verified by experiment,and the accuracy of output torque of measuring device system is demonstrated.According to the diversity of load forms of gravity download,different experimental schemes are made to study the friction moment of deep groove ball bearing under radial load,axial load,moment load and microgravity.The variation trend of friction moment of deep groove ball bearing under gravity and microgravity under variable load and variable speed is analyzed,and the friction moment of bearing is fitted according to the experimental results.Corresponding relationship between friction moment and load and speed of deep groove ball bearing under the same load.Finally,based on the experimental results,the mapping relationship between system output torque of bearing friction measuring device and bearing friction torque under gravity and microgravity is analyzed,and the corresponding mapping relationship expression is fitted.In addition,based on the similar theory and the mapping relationship of bearing friction moment of measuring device,the bearing friction moment of any spatial mechanism with single crank rotary motion mode and its mapping relationship under gravity and microgravity are analyzed.