Research And Implementation On Measurement Method For The Friction Torque Of Rolling Bearing

With the development of the equipment manufacturing industry, rolling bearing as highly interchangeable standard component part, its friction torque affects the energy loss and the accuracy of mechanical action and information transmission directly, so the startup friction torque and running friction torque measurement is required urgently by the manufacturing industry. The measurement technology for startup friction torque and running friction torque of the tapered roller bearing and deep groove ball bearing has been studied in this thesis.This paper presents the balance force theory and the error analysis for rolling bearing friction torque, and a method for measuring startup friction torque is put forward. The principle of running friction torque measurement is measuring the average value of torque on constant speed; the principle of startup friction torque measurement is that bearing inner ring rotates intermittently on low speed, the force of elastic traction line effecting on the outer ring increases slowly, the friction torque curve generated when the outer ring has relative movement to inner ring is measured by sensor, the extreme value point of the curve is startup friction torque, namely the critical point of relative movement between bearing inner ring and outer ring, the average starting friction torque is obtained by making average of extreme value point after the bearing moves a circle. At the same time, the measurement system which contains mechanical system and measurement and control system was given, and the design requirements of friction torque measurement system were given.A mechanical system which includes loading device, driving device and sensor is developed. Loading device provides axial load, driving device makes bearing inner ring rotate, and sensor gets the torque signal. Control the shape tolerance of spare parts and the fit tolerance to satisfy the precision requirements.Measurement and control system which includes hardware system and software system is developed. Hardware system includes control part and signal acquisition part. Control part which includes a servo motor, a servo drive, a motion control card and a industrial computer, completes movement control; signal acquisition part which includes a sensor, a retainer, an acquisition card and a industrial computer, it completes torque signal acquiring and processing. Software system includes program for running friction torque measurement and program for startup friction torque measurement.The running friction torque and startup friction torque measurement methods have been explored. And the precision of the measurement device has been verified by the experiments. The experimental results show that the repeatability accuracy of running friction torque isand the repeatability accuracy of startup friction torque is. So, the repeatability accuracy satisfies the requirements of the running friction torque and startup friction torque measurement for rolling bearing.