MANUFACTURE OF ONE-SIDE KEYSTONE TYPE PISTON RING HAVING STREAKS ON OUTER PERIPHERAL SURFACE

摘要

PURPOSE:To form uniform streaks on the outer pheripheral surface of a piston ring, by at first forming a slit on the annular ring having a rectangular cross- section, then forming said streaks on side surface simultaneously with tilting said surface so that its diameter decreases downward, subsequently forming a slant surface along the inner peripheral edge of the ring. CONSTITUTION:The outer and the inner peripheral surfaces 1a and 1b of the annular ring 1 having a rectangular cross-section are worked, and a part of the annular ring 1 is cut to form a slit. When a number of minute streaks are formed on the outer peripheral surface 1a, working is performed by slightly tilting the outer peripheral surface 1a simultaneously so that the diameter of the ring is reduced downward. Then, an slant surace 3 is formed on the inner peripheral edge part of the upper surface of the annular ring 1. As a result of this, the outer peripheral surface 1a is twisted, and the outer peripheral surface 1a of the annular ring 1 is formed into cylindrical form. Lastly, the surface of the annular ring 1 including the outer peripheral surface 1a is wrapping-processed, and the one-side keystone type piston ring having streaks on the outer peripheral surface is formed.