FRICTION BEHAVIOR OF HEAVY SPHERICAL BEARINGS IN ROTATION OF THE BRAIDED STRUCTURE COMPOSITE

The working principles and properties of a friction tester developed by the authors the are introduced for heavy load. The loading maximum value is 1000 kN. The varying ranges of its velocity are wide. The relationship between the friction coefficient and bearing capacity of the braided composites was explored at 2.5 r/min. Its friction time effect was measured. While the spherical bearing capacity of bearings was 135 MPa, the wear curve of bearings was measured. The relationship between temperature of bearings and continuous rotating time was explored. The curves of the friction coefficient varying with the continuous rotating time were measured. The results show that the dry friction coefficient is 0.038~0.061 when the load-carrying capacity of braided PTFE spherical bearings is 25~135 MPa. The mechanism of bearings' failure was analyzed by means of scanning electron microscopy. The PTFE of the braided composite is extruded in the process of the wear test. The self-lubricating function of spherical bearings is going down. The base of the braided composite is worn away.