Magnetic arc welded piston assembly
First Claim
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1. A magnetic arc welding method, comprising:
- providing a piston having a piston lower part defining a piston axis and having a combustion bowl portion and an upper piston part, wherein the combustion bowl portion includes a lower flange extending radially outwardly;
positioning the piston upper part in proximity to the piston lower part, wherein the piston upper and lower parts cooperate to define at least in part a cooling gallery extending annularly about the piston axis, wherein an upper surface of the lower flange extends underneath a lower surface of the piston upper part and radially external to the cooling gallery;
bringing the piston upper and lower parts together along respective upper and lower mating surfaces that are radially external to the cooling gallery, thereby partially forming the cooling gallery between the upper and lower parts, the upper and lower parts further defining a combustion bowl radially internal to the cooling gallery, wherein the upper and lower mating surfaces form a single circumferential contact area that extends from the combustion bowl to the cooling gallery;
connecting electrodes to the upper and lower piston parts for providing electric current;
positioning a magnetic coil within the combustion bowl;
inducing an electric current generated from the magnetic coil through the single circumferential contact area after bringing the upper and the lower mating surfaces in contact;
after the electric current is induced, spacing the upper and lower mating surfaces apart to form a gap between the upper and lower mating surfaces, thereby forming and maintaining an electric arc between the upper and lower mating surfaces, wherein the electric arc heats the upper and lower mating surfaces to a melt temperature; and
after the upper and the lower mating surfaces are at least softened, bringing the upper and lower mating surfaces back together to join the upper and lower mating surfaces and form a weld joint at the single circumferential contact area, and to bring the upper surface of the lower flange in contact with the lower surface of the piston upper part to fully form the combustion bowl and enclose the cooling gallery with the lower surface of the piston upper part thereof.
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Abstract
A piston and method of making the same includes providing a piston lower part defining a piston axis and at least a portion of the upper combustion bowl surface, and assembling a piston upper part to the piston lower part. The piston upper and lower parts cooperate to define at least in part a cooling gallery extending annularly about the piston. The method further includes bringing the piston upper and lower parts together along respective upper and lower mating surfaces and inducing an electric current between the upper and lower mating surfaces while the upper and lower mating surfaces are in contact.
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Citations
14 Claims
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1. A magnetic arc welding method, comprising:
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providing a piston having a piston lower part defining a piston axis and having a combustion bowl portion and an upper piston part, wherein the combustion bowl portion includes a lower flange extending radially outwardly; positioning the piston upper part in proximity to the piston lower part, wherein the piston upper and lower parts cooperate to define at least in part a cooling gallery extending annularly about the piston axis, wherein an upper surface of the lower flange extends underneath a lower surface of the piston upper part and radially external to the cooling gallery; bringing the piston upper and lower parts together along respective upper and lower mating surfaces that are radially external to the cooling gallery, thereby partially forming the cooling gallery between the upper and lower parts, the upper and lower parts further defining a combustion bowl radially internal to the cooling gallery, wherein the upper and lower mating surfaces form a single circumferential contact area that extends from the combustion bowl to the cooling gallery; connecting electrodes to the upper and lower piston parts for providing electric current; positioning a magnetic coil within the combustion bowl; inducing an electric current generated from the magnetic coil through the single circumferential contact area after bringing the upper and the lower mating surfaces in contact; after the electric current is induced, spacing the upper and lower mating surfaces apart to form a gap between the upper and lower mating surfaces, thereby forming and maintaining an electric arc between the upper and lower mating surfaces, wherein the electric arc heats the upper and lower mating surfaces to a melt temperature; and after the upper and the lower mating surfaces are at least softened, bringing the upper and lower mating surfaces back together to join the upper and lower mating surfaces and form a weld joint at the single circumferential contact area, and to bring the upper surface of the lower flange in contact with the lower surface of the piston upper part to fully form the combustion bowl and enclose the cooling gallery with the lower surface of the piston upper part thereof. - View Dependent Claims (2, 3, 4, 5, 9, 10, 13)
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6. A magnetic arc welding method, comprising:
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providing a piston having a piston lower part defining a piston axis and having a combustion bowl portion and an upper piston part, wherein the combustion bowl portion; assembling a piston upper part to the piston lower part, wherein the piston upper and lower parts cooperate to define at least in part a cooling gallery extending annularly about the piston axis, wherein the piston lower part includes a lower flange extending radially outwardly and radially external to the cooling gallery; bringing the piston upper and lower parts together along respective upper and lower mating surfaces that are radially external to the cooling gallery, thereby partially forming the cooling gallery between the upper and lower parts, the upper and lower parts further defining a combustion bowl radially internal to the cooling gallery, wherein the upper and lower mating surfaces form a single circumferential contact area that extends from the combustion bowl to the cooling gallery; connecting electrodes to the upper and lower piston parts for providing electric current; positioning a magnetic coil within the combustion bowl; inducing an electric current generated from the magnetic coil through the single circumferential contact area after bringing the upper and lower mating surfaces in contact; after the electric current is induced, spacing the upper and lower mating surfaces apart, thereby forming and maintaining an electric arc between the upper and lower mating surfaces, wherein the electric arc heats the upper and lower mating surfaces to a melt temperature; and after the upper and the lower mating surfaces are at least softened, joining the upper and lower mating surfaces together at the single circumferential contact area until an upper surface of the lower flange is in contact with the lower surface of the piston upper part to form a weld joint between the upper and the lower mating surfaces, and to enclose the cooling gallery with the lower surface of the piston upper part thereof. - View Dependent Claims (7, 8, 11, 12, 14)
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Specification