2019 年 85 巻 878 号 p. 19-00275
Mechanical systems have many joints within. It is well known that the parameters such as contact stiffness, static friction coefficient, kinetic friction coefficient and attenuation coefficient affect static, kinetic, thermal and motion characteristic of them strongly. In these parameters, the static friction coefficient reigns the character of maximum fixing resistance. However, conventional devices cannot be applied to measure the precise static friction coefficient on the coupling surfaces due to their tiny contact surface, unstable loading method and moment force acts on the contact surface. In this paper, we report a novel device we developed for measuring the static friction coefficient between fixed coupling surfaces which solves problems of the conventional devices. The new device enabled stable surface contact and uniform surface pressure by deploying the bearing unit with aligning function at the loading system. In addition, the frictional force applied on the same plane of the contact face of the specimen eliminated moment force. Furthermore, test result shows no component force except the load and frictional force. Moreover, the peak of the frictional force was successfully captured by choosing the proper sampling rate on data logger. Finally, the verification test confirmed that the developed measurement device is able to evaluate the influence of the surface roughness on the static friction coefficient.
