PISTON RING STRUCTURAL BODY AND MOUNTING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To improve durability of a piston ring structural body of a type pushing an outer ring formed endlessly with a resin material to the radial outer side by a ring tension offering member through an inner ring formed endlessly with a resin material. SOLUTION: A piston ring structural body 10 is made by pushing an outer ring 20 formed endlessly with a polyimide toward the radial outerside of the piston with a coil expander 40 through an inner ring 30 formed endlessly with a PTFE. The piston surface sliding on the cylinder wall 200 of the outer ring is divided into an upper side and a lower side sliding surfaces 24, 25 including chamfers 26, 27 on respective upper end peripheries by a groove 23 and the abutting part of the piston on the coil expander 40 of the inner ring 30 is formed with an upper side and a lower side slanting surfaces 33, 34 slanting to the upper and lower inner sides in an angle of 40 to 50 degrees.