Development of measurement device of static friction coefficient between fixed coupling surfaces

Abstract

Mechanical system has a lot of joints and each joint has coupling surfaces. The maximum fixing resistance of them is depending on static friction coefficient, and it effects static, kinetic and thermal characteristic strongly. There are many research regarding the static friction coefficient, however, they are not applicable for combination of the parameters of the coupling surfaces because of the problems of their measurement device. Therefore, in this paper, we developed new measurement device for static friction coefficient between fixed coupling surfaces which solves problems of the former devices. The new device enabled surface contact and uniform surface pressure by deploying the bearing unit with aligning function at loading part. It was confirmed that there's no moment force by generating the frictional force on same plane of the contact face of the specimen. Additional points were also checked that sampling rate is enough to catch the peak of the frictional force and there's no extra component force except load and frictional force. Finally, through verification test, the new measurement device proved that is able to evaluate the influence of surface roughness given to static friction coefficient.