Piston assembly
First Claim
Patent Images
1. A method, comprising:
- providing a piston crown blank defining a doughnut shape having a preformed central aperture;
forming from the piston crown blank a piston crown including a ring belt portion defining at least in part a cooling gallery;
receiving a piston skirt in a central opening of the crown such that the crown and skirt cooperate to form a continuous upper combustion bowl surface;
securing the skirt to the crown along a single circumferential interface region between the crown and skirt, the interface region including corresponding mating surfaces of the skirt and crown, the mating surfaces being oriented at an acute angle with respect to an axis of the skirt and the crown, the skirt and crown cooperating to define a radially outer gap between the skirt and the crown about a periphery of the piston crown; and
installing a cover plate to enclose the cooling gallery, the cover plate forming a lower boundary of the cooling gallery;
wherein the corresponding mating surfaces meet near a base of the combustion bowl such that the crown defines a radially outer portion of the combustion bowl surface and the skirt defines a radially inner portion of the combustion bowl surface;
wherein securing the skirt to the crown is achieved by welding from inside the combustion bowl radially outward toward the radially outer gap such that weld splatter is reduced in the cooling gallery.
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Abstract
Exemplary piston assemblies and methods of making the same are disclosed. An exemplary piston assembly may include a piston crown and a piston skirt that is received in a central opening of the crown. The piston crown may include a ring belt portion defining, at least in part, a cooling gallery. The crown and skirt may each further include corresponding mating surfaces that extend about a periphery of the crown and skirt. The skirt mating surface and crown mating surface may generally be secured to each other that the crown and the skirt cooperate to form a continuous upper combustion bowl surface. The skirt and crown may cooperate to define a radially outer gap about a periphery of the piston crown.
81 Citations
15 Claims
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1. A method, comprising:
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providing a piston crown blank defining a doughnut shape having a preformed central aperture; forming from the piston crown blank a piston crown including a ring belt portion defining at least in part a cooling gallery; receiving a piston skirt in a central opening of the crown such that the crown and skirt cooperate to form a continuous upper combustion bowl surface; securing the skirt to the crown along a single circumferential interface region between the crown and skirt, the interface region including corresponding mating surfaces of the skirt and crown, the mating surfaces being oriented at an acute angle with respect to an axis of the skirt and the crown, the skirt and crown cooperating to define a radially outer gap between the skirt and the crown about a periphery of the piston crown; and installing a cover plate to enclose the cooling gallery, the cover plate forming a lower boundary of the cooling gallery; wherein the corresponding mating surfaces meet near a base of the combustion bowl such that the crown defines a radially outer portion of the combustion bowl surface and the skirt defines a radially inner portion of the combustion bowl surface; wherein securing the skirt to the crown is achieved by welding from inside the combustion bowl radially outward toward the radially outer gap such that weld splatter is reduced in the cooling gallery. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method, comprising:
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providing a piston crown blank defining a doughnut shape having a preformed central aperture; forming from the piston crown blank a piston crown including a ring belt portion defining at least in part a cooling gallery; receiving a piston skirt in a central opening of the crown such that the crown and skirt cooperate to form a continuous upper combustion bowl surface; directing a laser toward a single circumferential interface region between the crown and skirt, the interface region including corresponding mating surfaces of the skirt and crown, the mating surfaces being oriented at an acute angle with respect to an axis of the skirt and the crown, thereby welding the skirt to the crown along the corresponding mating surfaces, the skirt and crown cooperating to define a radially outer gap between the skirt and the crown about a periphery of the piston crown; and installing a cover plate to enclose the cooling gallery, the cover plate forming a lower boundary of the cooling gallery; wherein the corresponding mating surfaces meet near a base of the combustion bowl such that the crown defines a radially outer portion of the combustion bowl surface and the skirt defines a radially inner portion of the combustion bowl surface; wherein the laser is directed from inside the combustion bowl radially outward toward the radially outer gap such that weld splatter is reduced in the cooling gallery. - View Dependent Claims (10, 11)
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12. A piston assembly, comprising:
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a piston crown, including a ring belt portion defining at least in part a cooling gallery, the crown including a crown mating surface extending about a periphery of the crown; a piston skirt received in a central opening of the crown, the skirt including a skirt mating surface extending about a periphery of the skirt, the crown and skirt mating surfaces included in a single circumferential interface region between the crown and skirt and oriented at an acute angle with respect to an axis of the skirt and the crown, the skirt secured to the crown by the interface region such that the crown and skirt cooperate to form a continuous upper combustion bowl surface, the skirt and crown cooperating to define a radially outer gap between the skirt and the crown about a periphery of the piston crown; wherein the corresponding mating surfaces meet near a base of the combustion bowl such that the crown defines a radially outer portion of the combustion bowl surface and the skirt defines a radially inner portion of the combustion bowl surface, and such that the mating surfaces are able to be welded from inside the combustion bowl radially outward toward the radially outer gap to reduce weld splatter in the cooling gallery; and wherein the corresponding mating surfaces have a single slope to define the sole connection between the crown and skirt. - View Dependent Claims (13, 14, 15)
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Specification