Pin body has lightening hole having one-end-side and another-end-side large diameter parts formed on both end sides in the longitudinal direction; a central small diameter part; one-end-side and another-end-side first rounded parts each being provided between the large diameter part and the central small diameter part, having an inner diameter decreasing from each large diameter part side toward the central small part side, and having a rate of change of the inner diameter increasing from each large diameter part side toward the central small diameter part side; and one-end-side and another-end-side second rounded parts each being provided between each first rounded part and the central small diameter part, having an inner diameter decreasing from each first rounded part toward the central small diameter part side, and having a rate of change of the inner diameter decreasing from each first rounded part toward the central small diameter part side.

Pin body has lightening hole having one-end-side and another-end-side large diameter parts formed on both end sides in the longitudinal direction; a central small diameter part; one-end-side and another-end-side first rounded parts each being provided between the large diameter part and the central small diameter part, having an inner diameter decreasing from each large diameter part side toward the central small part side, and having a rate of change of the inner diameter increasing from each large diameter part side toward the central small diameter part side; and one-end-side and another-end-side second rounded parts each being provided between each first rounded part and the central small diameter part, having an inner diameter decreasing from each first rounded part toward the central small diameter part side, and having a rate of change of the inner diameter decreasing from each first rounded part toward the central small diameter part side.

A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.

A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.

A method for producing a cooling duct piston for an internal combustion engine having a cooling duct in its piston crown. A piston main body is produced with a collar which is circumferential and projects radially in the region of the piston crown. The collar is formed until its outer circumferential edge comes very closely or completely into contact with a bearing region of the piston lower part forming the cooling duct. At least one ring groove is introduced. A ring-free groove is further formed below the ring groove, wherein a dividing plane lies between the outer circumferential edge of the formed collar and an upper side of the piston lower part in the ring-free groove.

A piston, particularly a piston for use in a diesel engine, particularly a heavy duty diesel engine, is formed from a billet of metal, such that the finished piston has a mass that is at least 50%, and, more preferably, up to about 62%, of the mass of the billet. Other than finishing steps, the piston is formed with a closed gallery, without loss of mass through machining processes.

The invention relates to a piston of an internal combustion engine including at least one peripheral annular groove. The piston includes an upper part and a lower part permanently joined in the region of a joining plane by a friction welding method. The joining plane may be located between the upper flank and the lower flank of the annular groove. A heat-affected zone is generated due to the use of the friction welding and includes at least one of the upper flank or the lower flank of the annular groove. Where multiple annual grooves are used, the joining plane and heat-affected zone may be positioned on alternate annular grooves.

A method for producing a piston for an internal combustion engine may include the steps of: producing a piston main body from a first blank via a deformation process; producing a piston ring part from a second blank via at least one of a deformation process and a casting process; pre-machining the first blank and the second blank, and finish machining a welding surface of the first blank and a welding surface of the second blank; connecting the pre-machined first blank and the pre-machined second blank via a welding process to form a piston body; and performing at least one of a secondary machining and a finish machining of the piston body to produce the piston.

A method for producing a piston for an internal combustion engine may include the steps of: producing a piston main body from a first blank via a deformation process; producing a piston ring part from a second blank via at least one of a deformation process and a casting process; pre-machining the first blank and the second blank, and finish machining a welding surface of the first blank and a welding surface of the second blank; connecting the pre-machined first blank and the pre-machined second blank via a welding process to form a piston body; and performing at least one of a secondary machining and a finish machining of the piston body to produce the piston.

A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.