Patent ID: 9739233
Date: 2017-08-22
CPC Classifications: F02B,F02F,F05C

Claim:
1. A piston of an internal combustion engine, comprising: a crown portion including a crown surface on which a combustion chamber is formed; a pair of thrust-side and counter-thrust-side skirt portions each of which is formed integrally with a reverse-surface-side portion of the crown portion and formed in an arc shape in cross section, the thrust-side and counter-thrust-side skirt portions being configured to slide on a wall surface of a cylinder; and a pair of apron portions connecting circumferential both ends of the thrust-side skirt portion with circumferential both ends of the counter-thrust-side skirt portion, the pair of apron portions each including wherein the reverse-surface-side portion of the crown portion is formed with a hollow portion extending along an outer surface of the upper end wall, wherein the upper end wall of each of the pair of apron portions includes a bending portion between an outside surface of the pin boss portion and one of the circumferential both ends of the thrust-side and counter-thrust-side skirt portions, wherein the bending portion bends in a step-like manner from the outside surface of the pin boss portion toward the one of the circumferential both ends of the thrust-side and counter-thrust-side skirt portions, wherein the bending portion in a transverse cross section of the piston that is perpendicular to a direction of movement of the crown portion in the cylinder includes wherein a length of the pin boss portion in an axial direction of the pin boss portion is greater than a thickness of the base end portion of the bending portion in the axial direction of the pin boss portion.