PISTON WITH WELD HARDENED RING GROOVE AND METHOD OF CONSTRUCTION THEREOF
First Claim
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1. A piston for an internal combustion engine, comprising:
- a top part having an uppermost surface with annular outer upper joining surface depending from said uppermost surface;
a bottom part having a pair of pin bosses providing a pair of laterally spaced pin bores aligned with one another along a pin bore axis and having an upwardly extending annular outer lower joining surface;
a friction weld joint bonding said upper joining surface to said lower joining surface; and
wherein at least one of said top part and said lower part has an annular ring groove configured for receipt of a piston ring, said ring groove having a thermally hardened surface within a heat affected zone of said friction weld joint.
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Abstract
A piston and method of construction is provided. The piston includes a top part and a bottom part fixed to one another. The bottom part includes a pair of pin bosses providing a pair of laterally spaced pin bores aligned with one another along a pin bore axis. A friction weld joint bonds the top part to the bottom part. The top part and/or the lower part has an annular ring groove configured for receipt of a piston ring, wherein the ring groove has a thermally hardened surface formed by a hardened region of the heat affected zone.
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Citations
19 Claims
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1. A piston for an internal combustion engine, comprising:
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a top part having an uppermost surface with annular outer upper joining surface depending from said uppermost surface; a bottom part having a pair of pin bosses providing a pair of laterally spaced pin bores aligned with one another along a pin bore axis and having an upwardly extending annular outer lower joining surface; a friction weld joint bonding said upper joining surface to said lower joining surface; and wherein at least one of said top part and said lower part has an annular ring groove configured for receipt of a piston ring, said ring groove having a thermally hardened surface within a heat affected zone of said friction weld joint. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10)
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3. The piston of claim 3 wherein said uppermost compression ring groove is the sole annular ring groove in said top part.
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11. A method of constructing a piston, comprising:
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providing a top part having an uppermost surface with annular outer upper joining surface depending from the uppermost surface; providing a bottom part having a pair of pin bosses providing a pair of laterally spaced pin bores aligned with one another along a pin bore axis and having an upwardly extending annular outer lower joining surface; forming a friction weld joint bonding the upper joining surface to the lower joining surface and forming a hardened region within a heat affected zone of the friction weld joint; and forming at least one annular piston ring groove in at least a portion of the hardened region of the heat affected zone. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification