Impact of rubber block end-face corner radius on the friction coefficient between rubber blocks and a glass plate under dry and lubrication conditions

The friction between a glass plate and rubber blocks with different end-face corner radii was investigated. Under dry conditions, rubber blocks with a large end-face corner radius (r = 0.83 mm) exhibited greater friction coefficients than those with a small end-face corner radius (r = 0.11 mm). Conversely, friction coefficients for r = 0.11 mm were greater than those for r = 0.83 mm under lubrication conditions. Further, the friction coefficients for r = 0.11 mm increased as the sliding velocity and lubricant viscosity increased owing to the formation of the fluid-free gap at the contact interface. •A rubber block with a large end-face corner radius shows large dry-sliding friction.•A rubber block with a large end-face corner radius shows a large dry-contact area.•A lubricated small end-face corner radius rubber block shows large sliding friction.•A gap formed at the contact interface for a small corner radius under lubrication.•Lubricated sliding friction increased as the gap area increased.