Abstract: In a light alloy piston each of the load-carrying skirt surfaces is divided by a depression into two load-carrying partial shaft surfaces.In order to reduce the friction losses and the consumption of lubricant the depth of the depression (8, 9) between the tapered portions of the curved generatrix (7) at the top and bottom ends of the skirt is approximately twice the peak-to-valley height of the machined surface of the skirt (1). The load-carrying partial skirt surfaces (10, 11, 12, 13) and the depression (8, 9) are at least as wide as the wear pattern area, and the axial extent of the depression (8, 9) is so selected that the depression will not protrude from the cylinder when the piston is at its lower dead center and in the cold engine the load-carrying partial skirt surfaces (10, 11, 12, 13) have between the upper limit of the depression and the lower limit of the tapered portion of the curved generatrix (7) at top end of the skirt an axially parallel portion in a height of 1.5 to 4.5 mm, preferably 1.

Abstract: A light alloy piston for internal combustion engines has a skirt which is closed at its lower end and at locations disposed adjacent to the bosses on both sides of the horizontal plane through the piston pin is set back so as to form respective recesses. In order to avoid a retention of oil in the recesses those end portions of the skirt which adjoin the recesses are inwardly offset from the outside peripheral surface of the piston.

Abstract: A piston for internal combustion engines, preferably made from aluminum alloy, has machined, oil-dragging grooves formed on the periphery of the piston skirt and concave transitions with a sawtoothlike profile with an obtuse profile angle. The piston skirt is provided with an electrodeposited hard iron layer having a thickness of 1-30 .mu.m and contains 0.5-6% metal-oxy compounds incorporated therein.