Abstract: An internal combustion engine piston having an internal cooling cavity structure is provided, which includes a piston body, and a ring body fitted with the piston body to form the internal cooling cavity structure. The ring body and the top of the piston body form a first fitting region, and the ring body and a top end of a skirt portion of the piston body form a second fitting region. The first fitting region includes a body fitting portion and a ring body fitting portion arranged at the top of the ring body. Compared with the conventional technology, the ring body welding cylindrical surface in the present application is fitted with the body welding cylinder surface, and the welding seam formed by the welding does not extend into the cooling cavity.

Abstract: A method for manufacturing piston with enclosed inner oil cooling chamber including 1) forging a blank of a piston body member and a blank of a piston ring member separately; 2) thermally treating the blank of the piston body member and the blank of the piston ring member separately; 3) sand blasting the blank of the piston body member and the blank of the piston ring member to form the inner cavity, the inner oil cooling chamber, and the laser welding surface; 4) welding the piston body member and the piston ring member together through laser welding procedure; 5) manufacturing the piston ring shaped groove, combustion chamber, ring groove, pinhole, outer circle, and the oil inlet/outlet holes, separately; and 6) phosphating or graphitizing the piston surface.

Abstract: A laser-welded single-piece forged-steel piston with an enclosed inner oil cooling chamber having the advantages of simple structure and easy manufacturing process, and capable of satisfying the requirement of engines for high power, high rigidity, and low discharge development, and its manufacturing process. The laser-welded single-piece forged-steel piston of the invention comprises a piston body member and a piston ring member, wherein the piston body member is welded together with the piston ring member through laser welding procedure, an enclosed inner oil cooling chamber is formed between the piston body member and the piston ring member, and is connected with the piston inner cavity by means of at least two oil inlet/outlet holes, and a pin hole is opened at the lower portion of the piston body member.

Abstract: The present invention has provided a welding forged steel single piece piston and its manufacturing methods. A semi-finished head and a semi-finished skirt are forged respectively; the semi-finished head and semi-finished skirt are heat-treated respectively; rough machining is carried out respectively to the semi-finished head and the semi-finished skirt, and a face of weld between the two adjacent ring grooves is higher than the one under the combustion chamber; the head and the skirt are welded together through friction welding; an annular groove, a combustion chamber, a ring groove, a pinhole, an outer annulus and oil inlet/outlet holes are manufactured respectively; and the surface of the piston is phosphorized and graphitized. Compared with one-piece forged piston, it has better processing technology, because the head and skirt are forged respectively and then welded together.