Piston for a reciprocating piston machine, particularly an internal combustion engine

Claim 1

A piston for a reciprocating piston machine, said piston being swivelled by means of a piston pin to an associated connecting rod small end and including a piston head and a piston skirt assembled together by stud bolts, the piston head comprising on its end surface adjacent to the piston skirt a central hollow forming a portion of a cooling chamber, the other portion of said chamber being formed by a central hollow provided in the adjacent end surface of the central portion of the piston skirt, said chamber comprising part of a cooling and lubricating system wherein said central portion of the piston skirt is constituted by a substantially cylindrical hollowed central boss provided with radial ribs to better distribute the force transmitted by the piston head, the connection of said central boss to the peripheral cylindrical surface of said piston skirt is by means of a peripheral annular crown with a flat upper surface perpendicular to the axis of the piston and delimited inwardly by a shoulder which is centered in the piston head hollow, the upper surface of said crown constituting the joint surface between the piston skirt and the piston head, and upon which bears the peripheral annular flat surface of the piston head delimited around said piston head hollow, each of said assembling stud bolts extending throughout an associated orifice machined in the annular crown of said central boss of the piston skirt and engaged into a tapped blind orifice machined in the piston head, said assembling stud bolts being accessible directly from the outside through the piston skirt and in the axial direction of said stud bolts.