Rolling bearing is a key basic component in many mechanical equipments, such as high speed railroad, heavy duty weapon and many other high-end equipments have the demand of rolling bearing. In the actual use of working conditions, with the improvement of mechanical equipment precision and speed, the rolling bearing performance requirements are also higher and higher. Rolling bearings in the actual use of the process is usually in the unsteady state conditions, unsteady state movement may lead to contact area lubricant film collapse, compared with the steady state conditions, rolling bearings in unsteady state conditions are more likely to lubrication failure, thus reducing the rolling bearing operation precision and service life, and observation of the contact area film thickness can reflect the lubrication state of the rolling bearings, bearings in the actual use of the working conditions of the distribution of lubricating oil and change. The distribution and change of the lubricant in the bearing under the actual operating conditions have an important influence on the stable operation and life of the rolling bearing, therefore, the observation of the change of the oil film morphology of the bearing under the real operating conditions is of great significance.
A rolling body rotates around the contact normal as it rolls. This rotational motion is called spin motion. The spin torque generated by the spin motion causes wear on the inner and outer rings of the bearing. Therefore, the study of elastic flow lubrication considering spin is of great importance. In order to simulate the common spin conditions in rolling bearings, a point contact elastohydrodynamic sliding-reciprocating spin experimental device that can precisely control the sliding speed and spin speed respectively is designed and developed. Ball-disc contact optical interference test is mostly used for lubrication performance and mechanism analysis because it is easy to change the kinematic parameters and observe the dynamic evolution of the oil film in the contact area. The effects of kinematic parameters and oil supply conditions on the film thickness distribution of point contact spin motion were investigated, and experiments were conducted for non-stationary conditions: sliding-reciprocating spin complex motion. The results indicated that the designed experimental device could accurately simulate the sliding reciprocating spin composite motion of the contact pair, and achieve visualization research on the oil film distribution under this condition. As the spin velocity of the steel ball increased, the symmetry of the classical horseshoe shape relative to the suction centerline disappeared. The higher the spin velocity, the more obvious the asymmetry, the greater the load, and the smaller the minimum oil film thickness. Under the unsteady-state, the oil film thickness at the moment of maximum spin velocity was lower than that at the same angular velocity under steady-state conditions; Increasing the frequency of reciprocating spin motion of the steel ball reduced the change in oil film thickness at the corresponding time. The reciprocating spin motion greatly reduced the inlet distance of the contact zone under the condition of oil shortage, which was consistent with the simulation results. In this paper, the study of different kinematic parameters and oil supply conditions on the rolling bearing spin condition was enlightened, which could help the stable movement of rolling bearings under the actual use of working conditions, improve the operating accuracy and service life of rolling bearings, and promote the further development of the theory of rolling bearing lubrication.
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