US 12,246,388 B2
Method of resistance spot welding and resistance spot welding apparatus
Shota Muto, Okazaki (JP)
Assigned to Futaba Industrial Co., Ltd., Okazaki (JP)
Filed by FUTABA INDUSTRIAL CO., LTD., Okazaki (JP)
Filed on Jun. 10, 2021, as Appl. No. 17/344,047.
Claims priority of application No. 2020-121332 (JP), filed on Jul. 15, 2020.
Prior Publication US 2022/0016726 A1, Jan. 20, 2022
Int. Cl. B23K 11/11 (2006.01); B23K 11/16 (2006.01); B23K 11/30 (2006.01); B23K 11/36 (2006.01)
CPC B23K 11/115 (2013.01) [B23K 11/163 (2013.01); B23K 11/3009 (2013.01); B23K 11/364 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A method of resistance spot welding, the method comprising welding a workpiece with a resistance spot welding apparatus, the workpiece including two or more steel plates in an overlapping state in a thickness direction,
the two or more steel plates including at least one steel plate coated with zinc,
the resistance spot welding apparatus including:
a first electrode configured to move in up-and-down directions, to thereby be downwardly in contact with a high-tensile steel plate having a tensile strength higher than a tensile strength of another steel plate among the two or more steel plates; and
a second electrode configured to be upwardly in contact with the workpiece, to thereby interpose such that the workpiece is interposed between the second electrode and the first electrode, and
the welding comprising:
in a state where the first electrode is in contact with the high-tensile steel plate arranged furthest above the workpiece and the second electrode is not in contact with the other steel plate, moving the first electrode downwards with the second electrode remaining fixed, to thereby place all of the two or more steel plates in a bent state holding all of the two or more steel plates by a jig in a bent manner in a direction so that a weld portion of the high-tensile steel plate, which is to be in contact with the first electrode, is positioned inside of a bend and place the other steel plate in a contact state with the second electrode; and
holding the bent state and the contact state by a jig arranged below the workpiece, to thereby compress the high-tensile steel plate in a direction intersecting a direction of a thickness of the high-tensile steel plate while welding, to thereby cancel a tensile stress generated in the high-tensile steel plate while welding, and
the jig including a first jig and a second jig that are arranged so as to interpose an imaginary line connecting a leading end of the first electrode and a leading end of the second electrode.