Patent ID: 8827277

Claim:
An oil-reserving piston ring, comprising an upper wedge ring ( 100 a , 200 a ) and a lower wedge ring ( 100 b , 200 b ) engaged with each other, the upper wedge ring ( 100 a , 200 a ) and the lower wedge ring ( 100 b , 200 b ) being each provided with an opening; the upper wedge ring ( 100 a , 200 a ) having a first working surface ( 101 , 201 ) contacting with the wall of a cylinder and the lower wedge ring ( 100 b , 200 b ) having a second working surface ( 102 , 202 ) contacting with the wall of the cylinder; characterized in that: at least one of the first working surface ( 101 , 201 ) and the second working surface ( 102 , 202 ) is arranged with at least one oil-reserving groove ( 105 , 106 , 205 , 206 ); wherein the openings of the upper wedge ring ( 100 a , 200 a ) and the lower wedge ring ( 100 b , 200 b ) each include an inside overlapping part ( 110 ) and an outside overlapping part ( 120 ); the inside overlapping part ( 110 ) includes an inner projection ( 110 a ), an outer recess ( 110 c ) and a first engaging portion ( 110 b ) connecting the inner projection ( 110 a ) and the outer recess ( 110 c ); the outside overlapping part ( 120 ) includes an outer projection ( 120 c ), an inner recess ( 120 a ) and a second engaging portion ( 120 b ) connecting the outer projection ( 120 c ) with the inner recess( 120 a ); the first engaging portion ( 110 b ) and the second engaging portion ( 120 b ) are engaged; there is a first gap ( 111 ) between the inner projection ( 110 a ) of the inside overlapping part ( 110 ) and the inner recess ( 120 a ) of the outside overlapping part ( 120 ); there is a second gap between the outer recess ( 110 c ) of the inside overlapping part ( 110 ) and the outer projection ( 120 c ) of the outside overlapping part ( 120 ).