Research & Design An Embedded Metrical System Of Friction Torque Of Miniature Bearings

There is a relative motion between inner-circle,outside-circle,holding shelf and scroll body during the running of a bearing and also generates a moment which baffling the running of the bearing, we define the moment as friction torque. The friction torque of bearing directly affects bearing's performance, and it is an important performance index of roll bearings. It directly affects the energy wastage, and has relation with the movement of the precise apparatus and the veracity of information transference. If the friction torque is too big, it will bring the temperature of the bearings, and that will break up the lubricant, prick up wastage, and even will bring to surface burnt and bearings mangled. It is a primary factor taken into account in the design of bearings, and emphasized in home and abroad. The friction tongue of bearings is a very complex issue; quantitative study and measurement of the friction torque are always tip topics for bearing industry and principal machine in the world.The measurement system for friction torque of miniature bearings will be researched and designed in this paper using the embedded and digital image process technology. The friction torque is measured indirectly by testing the defluxion angle of the pendulum pin which is fitted on the outer-circle of the bearings. The principal is that: the measured bearing is fitted on the horizontal rotation axis; the pin is fitted on the outer-circle of the bearing; the weight of the pin and the radius are to a certainty. When the inner-circle of the bearing is eddying on uniform speed along with the rotation axis, because of exist of the friction torque during outer-circle and inner-circle, the outer-circle and the pin will turn to an angle. If the friction torque is large, the angle is large and otherwise the angle is small. Then we snap the pin by digital video, and do image processing to the snapped image, and test the angle, eventually test the friction torque. The method used in this project is different from ones ever before. Compared to the current ones, ithas many outstanding features, for example: extra precision, convenience and legible, direct connection with the PC and data storage. This machine can measure the maximal friction torque while the bearing is under low speed.This paper introduces the principal of the friction torque measuring apparatus of miniature bearings, logic design of the system and the software design. The development of this system will provide dependable reference to the betterment of bearings'design parameters and machining technics, and the analysis of influencing factor of bearings friction torque, so improves the bearings'quality and mainframe's precision, and satisfies units of technical need of bearings'friction performance.