Piston and method of making a piston
First Claim
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1. A monobloc piston assembly for an internal combustion engine, comprising:
- a piston body extending along an axis, said piston body being formed of at least two pieces of material joined together by at least one weld joint which is a friction weld joint and which extends continuously through an annular shape around said axis;
one of said pieces having an upper surface with a combustion bowl formed therein, said combustion bowl having a rotationally asymmetrical shape around said axis; and
another of said pieces having a dome-shaped load-bearing receiving surface configured to engage and moveably support a portion of a connecting rod, and wherein said dome-shaped receiving surface is rotationally symmetrical about said axis.
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Abstract
A monobloc piston assembly for an internal combustion engine is provided. The piston assembly includes a piston body which extends along an axis and is formed of at least two pieces of material which are joined together at least one friction weld joint which extends continuously through an annular shape around the axis. One of the pieces has an upper surface with a combustion bowl having a rotationally asymmetrical shape around the axis formed therein. Another of the pieces has a dome-shaped receiving surface which is rotationally symmetrical around the axis for slidingly receiving a portion of a connecting rod.
26 Citations
19 Claims
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1. A monobloc piston assembly for an internal combustion engine, comprising:
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a piston body extending along an axis, said piston body being formed of at least two pieces of material joined together by at least one weld joint which is a friction weld joint and which extends continuously through an annular shape around said axis; one of said pieces having an upper surface with a combustion bowl formed therein, said combustion bowl having a rotationally asymmetrical shape around said axis; and another of said pieces having a dome-shaped load-bearing receiving surface configured to engage and moveably support a portion of a connecting rod, and wherein said dome-shaped receiving surface is rotationally symmetrical about said axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of making a piston, comprising the steps of:
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preparing a first piece of a piston body, the first piece having a combustion bowl formed in an upper surface thereof, and the combustion bowl having a rotationally asymmetrical shape about an axis; preparing a second piece of the piston body; and friction welding the first and second pieces of the piston body together. - View Dependent Claims (13, 14, 16, 17, 18)
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15. The method as set forth 12 wherein each of the first and second pieces has a pair of joining surfaces spaced radially from one another and wherein the step of friction welding the first and second pieces together includes friction welding the pieces together at the pairs of joining surfaces.
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19. A monobloc piston for an internal combustion engine, comprising:
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a piston body having at least two pieces joined by a friction weld joint to define at least one cavity there between and extending along a piston axis; one of said pieces having an upper surface with a combustion bowl having asymmetrical shape around said piston axis; one of said pieces having an upper surface with a combustion bowl having asymmetrical shape around said piston axis; another of said pieces having a part-spherical load bearing surface for engaging and moveably supporting a connecting rod; and said piston being free of laterally spaced pin bosses having pin bores aligned along a pin bore axis transverse to said piston axis.
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Specification