Patent ID: 7152567

Claim:
A piston for an internal combustion engine, comprising: a piston head; two pin bosses formed onto the piston head; at least one semi-circular lubricating groove machined into center regions of inside surfaces of the pin bores when viewed in a direction of a longitudinal axis of the pin bores, said at least one groove being circumferential at least over a nadir region and an equator region of the pin bores, said at least one groove having a center region with a flat cross section and a transverse width that lies parallel to the longitudinal axis of the pin bore and has a depth of less than 100 μm as compared with the inside surface of the pin bore, wherein toward an inside of the piston, the center region of the at least one lubrication groove is followed by a groove region which is inclined at a slant towards the inside of the piston and in the direction of the longitudinal axis, and encloses an acute angle of less than 3° with the longitudinal direction of the pin bore, and wherein towards an outside of the piston, the center region of the at least one lubrication groove is followed by a groove region that is inclined at a slant towards the outside of the piston and also in the direction of the longitudinal axis, and encloses an acute angle of less than 3° with the longitudinal direction of the pin bore.