Multi-axially forged piston
First Claim
1. A forged piston comprising:
- a piston head having a combustion bowl and a ring belt with a plurality of ring grooves formed therein;
a pair of pin bosses extending downwardly from said piston head having pin bores formed therein aligned along a common pin bore axis transverse to a longitudinal axis of the piston head;
a piston skirt forged as one piece with said pin bosses including a pair of opposed skirt portions spaced from said pin bosses and intervening strut portions extending between and uniting said skirt portions to said pin bosses, said strut portions presenting outer surfaces facing in opposite directions along said pin bore axis and having lower edges; and
forged recesses formed in said outer surfaces of said strut portions;
wherein said piston skirt portions are tapered so as to increase in thickness in the longitudinal direction of said piston from a lower end of said skirt portions toward said piston head as measured in a longitudinal plane perpendicular to said pin bore axis;
said piston skirt portion includes an outer wall and an inner wall, said inner wall being set at an angle with respect to said outer wall to provide a continuously increasing said thickness in the longitudinal direction away from said lower end of said skirt portions; and
wherein said angle is set at less than 3°
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Accused Products
Abstract
A multi-axially forged mono-bloc piston includes a lower crown part forged of steel and including a pair of pin bosses and an integral skirt formed as one piece with the pin bosses 20. The lower crown part is friction welded to an upper crown part to form at least one closed oil gallery within the piston head. The lower crown part is forged in the longitudinal direction of the piston as well as laterally to impart longitudinal and laterally forged features of the piston. The laterally forged features may comprise undercut recesses formed in the piston skirt to reduce material in the overall piston structure. The lateral forging may also result in the piston skirt portion being discoupled from the piston head by laterally forged slots formed in the lower crown part 14 between the skirt and head.
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Citations
32 Claims
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1. A forged piston comprising:
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a piston head having a combustion bowl and a ring belt with a plurality of ring grooves formed therein;
a pair of pin bosses extending downwardly from said piston head having pin bores formed therein aligned along a common pin bore axis transverse to a longitudinal axis of the piston head;
a piston skirt forged as one piece with said pin bosses including a pair of opposed skirt portions spaced from said pin bosses and intervening strut portions extending between and uniting said skirt portions to said pin bosses, said strut portions presenting outer surfaces facing in opposite directions along said pin bore axis and having lower edges; and
forged recesses formed in said outer surfaces of said strut portions;
wherein said piston skirt portions are tapered so as to increase in thickness in the longitudinal direction of said piston from a lower end of said skirt portions toward said piston head as measured in a longitudinal plane perpendicular to said pin bore axis;
said piston skirt portion includes an outer wall and an inner wall, said inner wall being set at an angle with respect to said outer wall to provide a continuously increasing said thickness in the longitudinal direction away from said lower end of said skirt portions; and
wherein said angle is set at less than 3°
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification