ROLLER TAPPET HAVING SI3N4 CERAMIC MADE SLIDING ROLLER

摘要

PURPOSE: To improve abrasion resistance on the sliding part of a cam, lighten a weight, and improve durability. CONSTITUTION: In an Si3 N4 ceramic made sliding roller 2 in which a roller to abut on a cam 4 is rotatably inserted directly, three point bending strength of Si3 N4 ceramic composing the sliding roller 2 is set to 100kg/mm<2> or higher in an average value. Each value of surface roughness of an outer circumference which is a sliding part of the cam 4 of the sliding roller 2 and the inner circumference which is a sliding part of a metal inner shaft 3 is set to 0.5μm and less in Rz, and may be set to 0.1μm and less so as to provide a roller tappet having a sliding roller.