Research On Torque Measuring Instrument And Elastic Fixture For Spherical Plain Bearing Assembly

Spherical plain bearings are widely used in aircraft doors and control system,the bearing assembly is affected by the shape and size errors of the bearing seat and journal parts,which results in the reduction of clearance and the increase of friction moment of the bearing after assembly,and affects the service performance of the bearing.In this paper,aiming at the problem of friction moment control of spherical plain bearings,the method of choosing bearing seat holes and journal dimensions during bearing assembly was studied,and an instrument for on-line measurement of friction moment during bearing assembly was developed.An elastic fixture was designed to simulate the assembling state of bearings.The deformation of the bearing and fixture of the elastic taper sleeve and hydraulic chuck fixture was analyzed by finite element simulation software.The problem of non-uniform radial deformation was discussed.Aiming at the hydraulic expanding clamp,the deformation of elastic expanding sleeve and mandrel when the internal cavity was subjected to hydraulic pressure was analyzed.The radial deformation of clamp and bearing when the cavity size of the clamp was different was analyzed by finite element simulation,and the cavity size of the clamp was optimized.The whole structure of the torquer with the function of dynamic display of measured data curve was designed,and the structure of the elastic element in the torque sensor was optimized.The influence of different clamping modes on the deformation of bearing itself was compared when measuring the friction moment of bearing.The clamping mode of bearing was determined when measuring the friction moment,and the step clamping head suitable for different sizes of bearing was designed.The data acquisition module of the torque instrument was designed,and the PCB board of the torque instrument was made by using Arduino MEGA250 as the core controller.The software system of the moment data acquisition instrument was developed,which includes the functions of moment signal acquisition and processing,data curve display and data management.The computer data management software based on Qt development platform was developed.The static calibration of the moment measuring instrument was carried out.The relationship between the measured moment and the digital output voltage of the sensor was established by fitting the calibration data.The static characteristics of the moment measuring instrument were analyzed,and the error sources of the lever calibration method were discussed.