Piston with leak-proof pressure reduction packing ring

A piston having leak-proof pressure-reducing piston ring belongs to an engine part, and solves the problem of large loss caused by the friction increase due to the thrusting force of high pressure gas on the piston ring. The utility model provides a piston ring structure made up of a piston ring groove inside which an inward-pressing ring and an outward-extending ring are vertically overlaid and tightly engaged to each other, so that the thrusting force of high pressure gas on the outward-extending ring is reduced, the loss due to the friction between the outward-extending ring and the cylinder inner wall is reduced, and multiple sealing surfaces are formed to enhance the sealing effect. Compared with the prior art, this piston has the advantages of low friction loss and energy consumption and no air leakage, and is widely used in mechanical power equipment based on high-pressure gas expansion.