Method and apparatus for making a two piece unitary piston

A two piece unitary piston, said two piece unitary piston comprising:

• a head member being made of a material having a preestablished material strength, having a bottom surface and an inner support portion defining a support surface;
• a skirt member being made of a material having a preestablished material strength being substantially the same as the preestablished material strength of said head member, having an upper outer support surface aligned with the bottom surface forming an interface and an inner support portion defining an upper inner support surface forming an interface and each of said interfaces being in contacting and supporting relationship with said bottom surface and said support surface of said head member respectively;
• said interface formed by said upper inner support surface being aligned with said support surface being joined by a welding process;
• said interface formed by said upper outer support surface being aligned with said bottom surface being joined by said welding process;
• a piston cooling gallery being formed by said upper inner support surface and said support surface interface and said upper outer support surface being aligned with said bottom surface interface;
• and
• said head member and said skirt member are formed as a single unit and being separated prior to said welding process.

A method of making a two piece unitary piston, said method of making comprising the steps of:

• forming a head member of a material having a preestablished strength, said forming defining an axis, a bottom surface and a support surface being spaced from said bottom surface;
• forming a skirt member of a material having a preestablished strength being substantially the same as the preestablished material of said head member, said forming defining an axis, an upper outer support surface and an upper inner support surface being spaced from said upper outer support surface;
• forming at least one of said bottom surface and said upper outer support surface, and said support surface and said upper inner support surface at an angle other than 90 degrees to said axis;
• positioning said bottom surface of said head member in contacting and supporting relationship with said upper outer support surface of said skirt member;
• positioning said support surface of said head member in contacting and supporting relationship with said upper inner support surface of said skirt member;
• welding said interface of said bottom surface and said upper outer support surface;
• welding said interface of said support surface and said upper inner support surface;
• and
• combining fixedly said head member and said skirt member forming a piston cooling gallery.

A method of making a two piece unitary piston, said method of making comprising the steps of:

• forming a head member of a material having a preestablished strength, said forming defining a bottom surface and a support surface being spaced from said bottom surface;
• forming a skirt member of a material having a preestablished strength being substantially the same as the preestablished material of said head member, said forming defining an upper outer support surface and an upper inner support surface being spaced from said upper outer support surface;
• forming a protrusion, said protrusion extending from an interface of said head member and said skirt member;
• positioning said bottom surface of said head member in contacting and supporting relationship with said upper outer support surface of said skirt member;
• positioning said support surface of said head member in contacting and supporting relationship with said upper inner support surface of said skirt member;
• welding said interface of said bottom surface and said upper outer support surface;
• welding said interface of said support surface and said upper inner support surface;
• and
• combining fixedly said head member and said skirt member forming a piston cooling gallery.

An engine including a block having a cylinder therein, said engine comprising:

• a head member being made of a material having a preestablished material strength, said head member having a bottom surface and an inner support portion being spaced from said bottom surface forming a head member;
• a skirt member being made of a material having a preestablished material strength being substantially the same as said preestablished material strength of said head member, said skirt member having an upper outer support surface being aligned with said bottom surface and forming an interface, said skirt member further having an upper inner support surface being aligned with said inner support portion and forming an interface, each of said interface being in contacting and supporting relationship with said bottom surface and said upper outer support surface, and said inner support portion and said upper inner support surface respectfully;
• at least one of said interface of said bottom surface and said upper outer support surface and said interface of said support surface and said upper inner support surface including a protrusion;
• a weld fixedly attaching each of said interfaces, and
• a piston cooling gallery being formed within at least one of said piston member and said skirt member.