Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Kyosuke Izuno

Hideaki Matsuoka

Tomohiko Sekiguchi

Shuhei Ogura

Tatsuyuki Amago

Koki Nakada

Hiroyuki Mori

Ayaka Kagami

Jun Yaokawa

Kohei Takahashi

Gaku Kitahara

Takashi Asada

Manabu Ooga

Takanori Nakagaki

Chikaumi Sawanishi

Yosuke Tamada

A welding determination method is provided, which determines whether a spot welding part is joined to an electrode without using resistance generated when separating the electrode from a workpiece. In the method, the workpiece made by laminating multiple metal sheets is clamped under pressure by a pair of electrodes and melted by a current applied, and after that the conduction is stopped to hold the workpiece in a pressurized state to determine whether the joining occurs. The method includes the steps of: deriving resistance between the pair of electrodes and pressurizing force by the pair of electrodes during conduction to the workpiece; and determining whether the spot welding part is joined to the electrodes based on a first index value calculated using the derived resistance and resistance in an ideal welding, and on a second index value calculated using the derived pressurizing force and pressurizing force in the ideal welding.

Welding determination method and spot welding equipment

A method of manufacturing a member for fastening by joining a nut with a tubular joint portion extending from a main body formed with an internal thread to a panel with a mounting hole for the nut on an aluminum base material. The joint portion has a rotation-preventing portion with a concave and convex shaped outer peripheral surface and a guide portion extending from the rotation-preventing portion to one side. After the guide portion is inserted into the mounting hole, the nut is energized by electrodes in contact with both nut end surface sides. The nut then generates heat, and the periphery of the mounting hole is heated and softened. When the nut is pressurized with the electrodes, the rotation-preventing portion bites into the mounting hole, and the one end portion of the guide portion is swaged to become a retaining portion on one surface side of the panel.

Member for fastening and method of manufacturing same

A spot welding method includes a heating step of energizing an electrode in pressure contact with an Al alloy member to heat and melt a join part by resistance heating and a cooling step of cooling the join part after the heating step in a state in which the electrode is in pressure contact with the Al alloy member. The alloy is a wrought alloy of Mg: 0.2 to 1.2 mass %, Si: 0.4 to 1.5%, and Cu: 1.1% or less or a casting alloy of Si: 7 to 11% and Mg: 0.1 to 0.4% with respect to 100% as a whole. The cooling step includes a first cooling process performed with a reduced amount of input energy to the join part as compared with the heating step and a second cooling process performed after the first cooling process at a higher cooling rate than that in the first cooling process.

Spot welding method

A novel spot welding method for steel sheets and an aluminum alloy sheet, includes stacked sheet materials from a pair of opposing electrodes to join the sheet materials by resistance heating. The pair of opposing electrodes are in pressure contact with both outer surfaces of the sheet sets. The sheet sets include at least a first and second steel sheet, and an aluminum alloy sheet stacked in this order. A first energization step forms a molten pool between facing surfaces of the first and second steel sheets without melting the aluminum alloy sheet. A second energization step causes a melting reaction between facing surfaces of the second steel sheet and the aluminum alloy sheet. The first and second steel sheets are joined via a first nugget. The second steel sheet and the aluminum alloy sheet are joined via a second nugget including an intermetallic compound generated by the melting reaction.

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Nisshin, Japan

Kyosuke Izuno