Hot forming of cooling galleries in steel pistons
AssigneeOhio State Innovation Foundation
InventorRajiv Shivpuri
Life of this patent
Estimating the term…
Abstract
A piston, particularly a piston for use in a diesel engine, particularly a heavy duty diesel engine, is formed from a billet of metal, such that the finished piston has a mass that is at least 50%, and, more preferably, up to about 62%, of the mass of the billet. Other than finishing steps, the piston is formed with a closed gallery, without loss of mass through machining processes.
Claims8
A method for forging a piston blank to a near-net shape, the method comprising:
- heating a billet;
- while heated, shaping the billet by hot forging to form a conical-shaped flange precursor;
- allowing cooling of the shaped billet;
- heating the conical-shaped flange precursor of the shaped billet, while maintaining a skirt portion at a temperature sufficiently cool to retain its shape;
- upsetting the conical shaped flange precursor of the billet to form a flange, thereby forming a near-net shape piston blank;
- and forming a closed gallery opposite the skirt portion without preliminary removal of material.
A method for forging a piston blank to a near-net shape, the method comprising:
- heating a steel billet;
- while heated, shaping the billet to form a flange precursor that is conical and a skirt portion;
- cooling the shaped billet;
- heating the flange precursor to temperatures permitting deformation while maintaining the skirt portion at a temperature substantially resisting deformation;
- upsetting the flange precursor of the billet to form a flange spaced apart from the skirt, thereby forming a near-net shape piston blank, the flange being spin-bendable to form a closed gallery without preliminary removal of material.
A method for forging a one-piece piston blank to a near-net shape, the method comprising:
- heating an entirety of a steel billet;
- shaping the billet to form (a) a flange precursor wherein at least a region of the flange precursor has a conical shape and (b) a hollow skirt portion;
- cooling the shaped billet;
- heating the flange precursor to temperatures permitting deformation while maintaining the skirt portion at a temperature preventing substantial deformation;
- upsetting the flange precursor of the billet to form a flange spaced apart from the hollow skirt while the hollow skirt retains its shape, and spin-bending the flange to form a closed gallery without preliminary removal of material by machining, thereby forming a near-net shape piston blank.
Dependencies are inferred from the claim text.