Hybrid induction welding process applied to piston manufacturing
First Claim
1. A method of manufacturing a piston, comprising the steps of:
- heating an upper joining surface of an upper piston part and a lower joining surface of a lower piston part by induction;
bringing the heated joining surfaces toward one another and allowing the heated joining surfaces to contact one another;
rotating one of the piston parts not more than 360 degrees in a first direction while the heated joining surfaces contact one another;
rotating the one piston part not more than 360 degrees in a second direction opposite the first direction while the heated joining surfaces contact one another;
applying pressure to at least one of the piston parts during the rotating steps to form a weld between the upper piston part and the lower piston part; and
the step of applying the pressure including increasing the pressure to a maximum pressure level and applying the maximum pressure level while rotating the one piston part in the second direction.
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Accused Products
Abstract
A hybrid induction welded piston including an upper piston part welded to a lower piston part is provided. The piston is produced by induction heating the upper piston part and the lower piston part, and bringing the parts together to a part growth compensated position. The method then includes rotating the upper piston part 17 to 34 degrees clockwise and then 17 to 34 degrees counterclockwise. In addition to controlling the axial position and degree of rotation, the force applied to the piston parts is controlled so that preferably no flash is formed in a narrow cooling chamber of the piston. During the rotating steps, the pressure gradually increases to a maximum level which occurs while the upper piston part is rotating in the second direction. The piston includes a homogenous metallurgical bond across the weld and no indentation on the outer surface at the weld prior to machining.
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Citations
36 Claims
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1. A method of manufacturing a piston, comprising the steps of:
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heating an upper joining surface of an upper piston part and a lower joining surface of a lower piston part by induction; bringing the heated joining surfaces toward one another and allowing the heated joining surfaces to contact one another; rotating one of the piston parts not more than 360 degrees in a first direction while the heated joining surfaces contact one another; rotating the one piston part not more than 360 degrees in a second direction opposite the first direction while the heated joining surfaces contact one another; applying pressure to at least one of the piston parts during the rotating steps to form a weld between the upper piston part and the lower piston part; and the step of applying the pressure including increasing the pressure to a maximum pressure level and applying the maximum pressure level while rotating the one piston part in the second direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of manufacturing a piston, comprising the steps of:
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heating an upper joining surface of an upper piston part and a lower joining surface of a lower piston part by induction, wherein the volume of at least one of the piston parts increases from a starting volume to a final volume due to the induction heating; bringing the heated joining surfaces toward one another and allowing the heated joining surfaces to contact one another; rotating one of the piston parts not more than 360 degrees in a first direction while the heated joining surfaces contact one another; rotating the one piston part not more than 360 degrees in a second direction opposite the first direction while the heated joining surfaces contact one another; applying pressure to at least one of the piston parts during the rotating steps to form a weld between the upper piston part and the lower piston part; and the step of bringing the heated joining surfaces toward one another includes bringing the heated joining surfaces to a part growth compensated position before the volume of the at least one piston part reaches the final volume, wherein the part growth compensated position provides a space between the joining surfaces which compensates for the increase in volume. - View Dependent Claims (23, 24)
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25. A method of manufacturing a piston, comprising the steps of:
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heating an upper joining surface of an upper piston part and a lower joining surface of a lower piston part by induction; bringing the heated joining surfaces toward one another and allowing the heated joining surfaces to contact one another; rotating at least one of the piston parts in a first direction while the heated joining surfaces contact one another; applying pressure to at least one of the piston parts during the rotating steps to form a weld between the upper piston part and the lower piston part; and the step of applying the pressure including increasing the pressure to a maximum pressure level and applying the maximum pressure level while rotating the one piston part in a second direction opposite the first direction.
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26. A method of manufacturing a piston, comprising the steps of:
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heating an upper joining surface of an upper piston part and a lower joining surface of a lower piston part by induction; bringing the heated joining surfaces toward one another and allowing the heated joining surfaces to contact one another; rotating at least one of the piston parts while the heated joining surfaces contact one another; applying pressure to at least one of the piston parts during the rotating steps to form a weld between the upper piston part and the lower piston part; wherein the volume of at least one of the piston parts increases from a starting volume to a final volume due to the induction heating; the step of bringing the heated joining surfaces toward one another includes bringing the heated joining surfaces to a part growth compensated position before the volume of the at least one piston part reaches the final volume; and wherein the part growth compensated position provides a space between the joining surfaces which compensates for the increase in volume.
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27. A piston, comprising:
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an upper piston part including an upper joining surface; a lower piston part including a lower joining surface welded to said upper joining surface; a portion of said upper piston part and a portion of said lower piston part located along said weld together presenting an outer surface; and said outer surface of said portions located along said weld being free of an indentation prior to machining said outer surface and wherein said weld has been twisted in opposite first and second directions to achieve said indentation-free surface. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification