Dust Generation Properties of Solid Lubricant Film Coated and Perfluoropolyether Lubricated Ball Bearings

The purpose of this work is to elucidate the properties of ball bearings used for clean applications. Dust, namely wear debris particle generation behavior of ball bearings lubricated with solid lubricant films and low vapor pressure PFPE (perfluoropolyether) grease was investigated using a laser scattering type dust counter under small-angle oscillatory conditions. In the case of the solid lubricated bearing, dust generation began to increase rapidly at a certain number of oscillatory cycles, as deduced from the bearing surface damage. Bearings lubricated with a $MoS2/Ag$ layer and $MoS2$ sputtered films showed less dust generation, starting torque and surface damage than ion-plated Ag and Au film lubricated and unlubricated bearings. Dust generation was deduced to be due to the damage formation of oscillatory ball bearings, based on the size of the contact elliptic area. The total number of particles generated from the ball bearing lubricated with PFPE grease is very large, but bearing damage is very small. Degraded PFPE was observed on the side plate seal by FTIR. Therefore, dust generation from a PFPE-lubricated bearing is deduced to be due to PFPE degradation. Particles generated from bearings with dry contact include large particles. In contrast, most of the particles generated from bearings lubricated with PFPE grease are very small. Side plate seals of ball bearings decrease the amount of dust generated from these bearings. [S0742-4787(00)00704-9]