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Magnetic arc welded piston assembly

  • US 10,449,621 B2
  • Filed: 04/16/2015
  • Issued: 10/22/2019
  • Est. Priority Date: 05/01/2014
  • Status: Active Grant
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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