This standard specifies the basic structure, size series and tolerance of QY, C, C, J, ZHM polyurethane rubber seals and QH exposed skeleton rubber buffer seals for cylinders. This standard is applicable to seals for cylinders with compressed air as the medium, a medium temperature of -20~80℃, and a working pressure not exceeding 1.6MPa. Among them, QY type is used to guide the one-way sealing function on the cylinder piston and piston rod; C type and CK type are suitable for the two-way sealing function on the piston and piston rod of oil-free lubrication cylinders; J type is for dustproof of piston rod; ZHM type is for dustproof sealing of piston rod; GH type is a buffer seal. JB/T 6657-1993 Size series and tolerances of cylinder seals JB/T6657-1993 Standard download decompression password: www.bzxz.net