Complex-shaped piston oil galleries with piston crowns made by cast metal or powder metal processes
AssigneeFederal-Mogul Corporation
InventorNorbert G. Schneider
Life of this patent
Estimating the term…
Abstract
A steel piston with an oil gallery, and process for forming a steel piston oil gallery channel, which corresponds to the complex shape of the combustion bowl in the piston crown. The piston crown is made by a cast metal or powder metal forming process. The oil gallery channel is formed to the basic shape that corresponds to the shape of the walls of the combustion bowl. Machine-turning surfaces in the oil gallery channel can be machine-finished as desired. Surfaces in the oil gallery which cannot be machined with conventional turning operations, such as recesses and protrusions into the channel, are left in the original as-formed condition.
Claims15
A piston comprising:
- a lower member, said lower member comprising sidewall portions and pin bores;
- an upper crown member joined to said lower member, said upper crown member being made of a metal material and having a complex shaped combustion bowl on an upper side thereof and an oil gallery channel on the lower side thereof, wherein said oil gallery channel includes a machine-formed radially outward circular wall surface and a radially inward wall surface, said radially inward wall surface having a same complex-shaped configuration as said combustion bowl, and said radially inward wall surface having first machine formed portions and second as-formed portions, wherein said machine-formed portions and said as-formed portions on said inward wall surface being positioned alternatively around a circumference of said inward wall surface.
A piston comprising:
- a lower crown;
- an upper crown joined to said lower crown, said upper crown being made of a metal material and having a complex shaped combustion bowl on an upper side thereof and an oil gallery channel on a lower side thereof, wherein said oil gallery channel has a corresponding complex shape and includes a machine-formed circular radially outward wall surface and a radially inward wall surface, said radially inward wall surface having the same complex-shaped configuration as said combustion bowl, and said radially inward wall surface having first machine formed portions and second as-formed portions, wherein said radially inward wall surface comprises multiple radially inward recessed as-formed portions separated circumferentially from one another by intervening sections of machine-formed wall surface portions.
A piston for an internal combustion engine, comprising:
- a steel piston crown member having a complex shaped combustion bowl;
- an oil gallery channel in the piston crown member having a shape corresponding to the complex shape of the combustion bowl, said shape of the oil gallery channel being formed by a cast metal or powder metal forming process;
- and
- a lower piston member attached to said piston crown member, said lower piston member having sidewall members and pin bores;
- said oil gallery channel having a circular radially outward machine-formed wall surface, and a radially inward wall surface, said radially inward wall surface having circumferentially alternating portions of machine-formed surfaces and as-formed surfaces.
A method for forming an oil gallery channel in a steel piston crown member, said method comprising the steps of:
- providing a piston crown member made of a steel material and having an upper surface and a lower surface;
- forming a complex shaped combustion bowl in the upper surface of said piston crown member;
- forming a complex shaped oil gallery channel in the lower surface of said piston crown member, the oil gallery channel having a shape corresponding to the complex shape of the combustion bowl;
- said oil gallery channel having a radially inward wall surface and a radially outward wall surface;
- machine-forming the radially outward wall surface of said oil gallery channel;
- and
- machine-forming portions of the radially inward wall surface of said oil gallery channel and leaving portions of said radially inward wall surface as formed,
- wherein said machine-formed portions of said radially inward wall surface are alternatively positioned with said as-formed portions of said radially inward wall surface around a circumference of said inward wall surface.
Dependencies are inferred from the claim text.