OIL-RESERVING PISTON RINGAn oil-reserving piston ring includes an upper wedge ring (100a,200a) and a lower wedge ring (100b,200b) jointed with each other. The upper wedge ring (100a,200a) and the lower wedge ring (100b,200b) …DRIVE·Jun 26·1 min readFollowF02F5/00YANG ZENGLI [CN]
