Research On Friction Torque Measurement Of Rolling Bearing Under Radial Load

Bearing is widely used in mechanical and other engineering field,and its performance directly affects the overall mechanical properties.The bearing friction torque can cause the energy loss and lead to the temperature of the bearing rise,so as to affect the service life of the bearing.Friction torque is a very important technical indicator to evaluate the bearing rotating flexibility and life,so many countries pay more and more attention to the detection of bearing friction torque.In this paper,a study of the measurement for bearing running friction torque and startup friction torque under radial load was introduced.A feasible scheme to measure the friction torque of rolling bearing under radial load based on the balance force theory was given in this paper.In the scheme,the radial load of the bearing was adopted by using the gravity of the weights.The running friction torque was measured when the bearing was running at a constant speed and the average value of the measured data was given as the result of measurement for the running friction torque.The startup friction torque was measured while the inner ring ran at a very low speed.The inner ring of the bearing was controlled to move intermittently.After the inner ring has rotated by a full turn,the key point values were chosen and the average value was calculated as the startup friction torque measuring result.A rolling bearing friction torque under radial load measurement system was designed,including the mechanical part and the measuring and control part.The mechanical part mainly contains the bearing positioning device,the driving device,the loading device and the sensor fixing device.The measurement and control part contains the hardware design and the software design.The main hardware in the whole measurement system include the servo motor,the servo amplifier,the force sensor,the signal acquisition card,PLC,PC and so on.The motion control part of the software design was based on the Mitsubishi PLC motion control technology to realize the control of the servo motor,and the data acquisition and processing part was based on the Lab VIEW virtual instrument technology to realize the data acquisition and analysis processing.A calibration method for rolling bearing friction torque measuring device was given in this paper and the device was calibrated.The precision of the measurement device has been verified by the experiments.The experimental results show that the repeatability accuracy of the running friction torque is ±10m N·m and the repeatability accuracy of startup friction torque is ±5m N·m.