Steel piston with cooling gallery and method of construction thereof
First Claim
1. A piston for an internal combustion engine, comprising:
- a top part having an uppermost surface with annular inner and outer upper joining surfaces 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 a pair of upwardly extending annular inner and outer lower joining surfaces joined by separate respective inner and outer weld joints to said inner and outer upper joining surfaces with an annular cooling gallery formed radially between said upper joining surfaces and radially between said lower joining surfaces, said bottom part having a combustion bowl wall recessed below said uppermost surface, said combustion bowl wall having an upper apex and an annular valley surrounding said upper apex and a lower apex underlying said upper apex; and
wherein said inner weld joint is substantially coplanar with said lower apex.
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Abstract
A piston and method of construction is provided. The piston includes a top part fixed to a bottom part. The top part has an uppermost surface with annular inner and outer upper joining surfaces depending therefrom. The bottom part has a pair of pin bosses with pin bores aligned with one another along a pin bore axis; a pair of upwardly extending annular inner and outer lower joining surfaces and a combustion bowl wall. Inner and outer weld joints fix the inner and outer upper and lower joining surfaces to one another. An annular cooling gallery is formed laterally between the upper and lower joining surfaces. The inner weld joint joining the top part to the bottom part is located within the combustion bowl wall and configured to minimized the compression height of the piston.
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Citations
25 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 inner and outer upper joining surfaces 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 a pair of upwardly extending annular inner and outer lower joining surfaces joined by separate respective inner and outer weld joints to said inner and outer upper joining surfaces with an annular cooling gallery formed radially between said upper joining surfaces and radially between said lower joining surfaces, said bottom part having a combustion bowl wall recessed below said uppermost surface, said combustion bowl wall having an upper apex and an annular valley surrounding said upper apex and a lower apex underlying said upper apex; and wherein said inner weld joint is substantially coplanar with said lower apex. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of constructing a piston for an internal combustion engine, comprising:
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forming a top part having an uppermost surface with annular inner and outer upper joining surfaces depending from the uppermost surface; casting 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 a pair of annular inner and outer lower joining surfaces extending upwardly from the pin bores with a combustion bowl wall recessed below the uppermost surface, the combustion bowl wall being formed having an upper apex and an annular valley surrounding the upper apex and a lower apex underlying the upper apex; welding the top part to the bottom part by forming separate inner and outer weld joints between the respective inner and outer upper joining surfaces and forming an annular cooling gallery radially between the upper joining surfaces and radially between the lower joining surfaces; and further including forming the inner weld joint in substantially coplanar relation with the lower apex of the combustion bowl. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification