Development Of Data Acquisition System For Slewing Bearing's Contact Force Measurement And Corresponding Experiment

Large slewing bearings have a wide range of applications in construction machinery and are an important mechanical component.In many cases,the working state of the slewing bearing directly affects whether the entire mechanical system can operate normally.The slewing bearing is mainly loaded by the large axial force and the overturning moment in the actual working condition,and the external load applied to the slewing bearing causes the rolling body and the raceway to press each other,thereby generating a contact load.The contact load inside the slewing bearing will have a great influence on the life and use of the slewing bearing.However,when the slewing bearing is affected by the external load,the contact load between the rolling element and the raceway at different positions inside the bearing is generally different.Therefore,it is meaningful to study the measurement method of the contact load of the slewing bearing.However,at present,most of the research on the contact load of the slewing bearing is analyzed by the theoretical calculation method,and the related experimental tests are relatively few.This topic is derived from the basic research of the impact of bolting and supporting structures on the life of large slewing bearings funded by the National Natural Science Foundation of China(Grant No.: 51465025).The research goal of this paper is to build a data acquisition system for the turret bearing contact force measurement test bench,to measure the contact deformation of the slewing bearing ball and the raceway when the bolt is non-uniformly preloaded,and calculate the non-uniform preload of the bolt by accurate finite element calculation.The contact force of the turret bearing ball and the raceway.Firstly,this paper develops a data acquisition system based on Omron PLC,installs and connects the eddy current displacement sensor with Omron PLC main unit and slewing bearing,and visually displays the displacement data collected by the host computer.Because the contact stress of the slewing bearing is very large in actualworking conditions,it is likely to exceed 1GPa.Due to the size limitation of the sensor,the direct measurement of the contact load by the sensor is not operability,but the measurement of the deformation displacement data is More convenient.Therefore,the measurement of the contact force of the slewing bearing is indirectly achieved by measuring the displacement.Secondly,the displacement sensor used was calibrated and calibrated.The experiment of internal contact deformation and axial displacement measurement of the slewing bearing under five different bolt preload conditions was carried out,and the deformation of the slewing bearing under different preload conditions was obtained.Displacement data.At the same time,the experimental data of the rolling element and the track contact deformation displacement measured by the eddy current displacement sensor and the axial displacement at the end face of the slewing bearing are used to calculate the actual contact angle of the slewing bearing under non-uniform preload.Finally,this paper uses a method to indirectly measure the contact load of the slewing bearing.The finite element analysis model of the single rolling element and the raceway contact of the slewing bearing is constructed.ANSYS finite element analysis software is used to apply an external load on the inner ring of the slewing bearing to adjust the size of the external load,so that the contact deformation displacement obtained in the simulation calculation is The displacement values obtained by the experimental measurements are sufficiently close,and the contact load between the rolling element and the raceway is calculated by the relationship between the contact load and the contact deformation.At the same time,the changes of the contact load of the slewing bearing under non-uniform preloading are summarized.