Piston assembly with preloaded support surfaces

A piston assembly, comprising:

• a crown having an upper combustion bowl surface and a ring belt portion disposed about the combustion bowl, the crown defining an upper cooling gallery surface, a radially outer crown support surface, and a radially inner crown support surface, the crown having an axial support extending away from the combustion bowl, the axial support having a first diameter and a second diameter larger than the first diameter, the radially inner and outer crown support surfaces spaced radially away from the axial support;
• and
• a skirt defining a lower cooling gallery surface cooperating with the upper cooling gallery surface to define at least in part a cooling gallery extending about a perimeter of the piston, the skirt defining an aperture receiving the first diameter of the axial support such that the second diameter of the axial support is supported in the skirt on a side of the aperture opposite the crown;
• wherein the skirt defines radially inner and outer skirt support surfaces, the radially inner skirt support surface abutted against the radially inner crown support surface with a radially inner preload, and the radially outer skirt support surface is abutted against the radially outer crown support surface with a radially outer preload;
• wherein an end portion of the axial support is deformed, thereby facilitating the abuttings.

A method of assembling a piston, comprising:

• providing a crown having an upper combustion bowl surface and a ring belt portion disposed about the combustion bowl, a radially outer crown support surface, and a radially inner crown support surface, the crown having an axial support extending away from the combustion bowl, the radially inner and outer crown support surfaces being spaced radially away from the axial support;
• inserting the axial support into an aperture of a skirt the aperture including an annular surface defining an oblique angle with respect to a longitudinal axis of the piston, the skirt defining radially inner and outer skirt support surfaces;
• deforming an end portion of the axial support to apply a compressive force between the crown and the skirt, thereby abutting the radially inner skirt support surface against the radially inner crown support surface to define a radially inner preload and abutting the radially outer skirt support surface against the radially outer crown support surface to define a radially outer preload;
• and
• adjusting a vector component of preload in an axial direction and adjusting a vector component of preload in a radial direction by way of a selection of a value of the oblique angle.