Piston for an internal combustion engine and method for producing the piston

Method for the production of a piston (1, 1′, 1″) for an internal combustion engine, having a piston crown (2), having a ring belt (4) disposed in the vicinity of the piston crown, on the radial outside of the piston (1, 1′, 1″), having two pin bosses (10, 10′, 10″, 11, 11′, 11″) that follow the ring belt (4) in the direction facing away from the piston crown and lie opposite one another, which bosses are connected with one another by way of skirt elements (14), and having a pin bore (12, 12′, 12″, 13, 13′, 13″) introduced into the pin bosses (10, 10′, 10″, 11, 11′, 11″), in each instance, comprising the following method steps:

• introducing a lathe tool of a lathe, mounted so as to rotate, which tool has a cutting surface disposed radially on the outside, into the pin bore (12, 12′, 12″, 13, 13′, 13″),
• positioning the lathe tool at the location of the pin bore (12, 12′, 12″, 13, 13′, 13″) at which a lubrication groove (15, 16, 20, 21, 24 to 31) is to be introduced,
• displacing the rotating lathe tool in a direction facing away from the piston crown (2), until the lubrication groove (15, 16, 20, 21, 24 to 31) has the desired depth.

Method for the production of a piston (1, 1′, 1″) for an internal combustion engine, having a piston crown (2), having a ring belt (4) disposed in the vicinity of the piston crown, on the radial outside of the piston (1, 1′, 1″), having two pin bosses (10, 10′, 10″, 11, 11′, 11″) that follow the ring belt (4) in the direction facing away from the piston crown and lie opposite one another, which bosses are connected with one another by way of skirt elements (14), and having a pin bore (12, 12′, 12″, 13, 13′, 13″) introduced into the pin bosses (10, 10′, 10″, 11, 11′, 11″), in each instance, comprising the following method steps:

• introducing a lathe tool of a lathe, mounted so as to rotate, which tool has a cutting surface disposed radially on the outside, into the pin bore (12, 12′, 12″, 13, 13′, 13″),
• positioning the lathe tool at the location of the pin bore (12, 12′, 12″, 13, 13′, 13″) at which a lubrication groove (15, 16, 20, 21, 24 to 31) is to be introduced,
• displacing the piston (1, 1′, 1″) relative to the rotating lathe tool, in such a direction that the distance between the lathe tool and the piston crown (2) increases, until the lubrication groove (15, 16, 20, 21, 24 to 31) has the desired depth.

Method for the production of a piston (1″) for an internal combustion engine, having a piston crown (2), having a ring belt (4) disposed in the vicinity of the piston crown, on the radial outside of the piston (1″), having two pin bosses (10″, 11″) that follow the ring belt (4) in the direction facing away from the piston crown and lie opposite one another, which bosses are connected with one another by way of skirt elements (14), and having a pin bore (12″, 13″) introduced into the pin bosses (10″, 11″), in each instance, comprising the following method steps:

• positioning the lathe tool in front of the pin bore (12″, 13″), to such an extent that the axis of rotation of the lathe tool lies parallel to the pin bore axis (18) and lies farther away from the piston crown (2) by 1 μm to 500 μm than the pin bore axis (18),
• guiding the rotating lathe tool through the pin bore (12″, 13″) in the direction of the pin bore axis (18), wherein the distance between the cutting surface of the lathe tool and the axis of rotation of the lathe tool is selected in such a manner that the lathe tool exclusively comes into contact with the nadir and the equator of the pin bore, and that in this connection, lubrication grooves (24 to 31) occur in the nadir and in the equator of the pin bore (12″, 13″), which have a depth of 1 μm to 500 μm.