# US 2013/0153544 A1 · Welding method and welding device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153544 A1 - Document ID: US20130153544A1 - Status: Published application - Kind: A1 - Application number: 13/820,623 - Filed: 2011-09-05 - Published: 2013-06-20 - Earliest claimed: 2010-09-06 - Assignees: Honda Motor Co., Ltd. - Inventors: Akira Goto; Shinichi Miyasaka; Tatsuro Ikeda; Yushi Aoki; Mitsutaka Igaue - Web page: https://patentgrep.com/patent/US20130153544A1 ## CPC - B23K 11/115: {by means of two electrodes placed opposite one another on both sides of the welded parts} - B23K 11/314: {Spot welding guns, e.g. mounted on robots} - B23K 11/36: Auxiliary equipment (B23K11/31 takes precedence) - B23K 37/0435: {Clamps} - B23K 2101/18: Sheet panels - B23K 2103/04: Steel {or steel} alloys - B23K 2103/14: Titanium or alloys thereof - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM ## Abstract A resistance welding device is provided with a lower tip and an upper tip that serve as welding tips, and pressing rods that serve as pressing members. The upper tip and the pressing rods press a stacked body, which is to be welded, from the metallic plate side, which is the outermost member of the stacked body. The lower tip presses the stacked body from the lowermost metallic plate side. In this state, and electric current is conducted from the upper tip to the lower tip. ## Claims ### Claim 1 A resistance welding method for carrying out resistance welding with respect to a stacked body formed by stacking a plurality of workpieces, comprising the steps of: sandwiching the stacked body between a first welding tip and a second welding tip, while bringing a pressing member into abutment against an outermost workpiece, which is positioned on an outermost portion of the stacked body and against which the first welding tip is in abutment, the stacked body being pressed from a side of the outermost workpiece by the pressing member; and conducting an electric current between the first welding tip and the second welding tip while maintaining a pressure by the pressing member. ### Claim 2 (depends on 1) The resistance welding method according to claim 1, wherein the pressing member comprises an auxiliary electrode having a polarity opposite to that of the first welding tip, such that when electric current is conducted between the first welding tip and the second welding tip, a branching current is made to flow either from the first welding tip to the auxiliary electrode, or from the auxiliary electrode to the first welding tip. ### Claim 3 (depends on 2) The resistance welding method according to claim 2, wherein another auxiliary electrode, which has a polarity opposite to that of the second welding tip, is provided on a side of the second welding tip, such that after either one of the branching current that flows from the first welding tip to the auxiliary electrode or the branching current that flows from the auxiliary electrode to the first welding tip has vanished, a branching current flows either from the other auxiliary electrode to the second welding tip, or from the second welding tip the other auxiliary electrode. ### Claim 4 A resistance welding method for carrying out resistance welding with respect to a stacked body formed by stacking a plurality of workpieces, comprising the steps of: sandwiching the stacked body between a first welding tip and a second welding tip, and bringing an auxiliary electrode having a polarity opposite to that of the first welding tip into abutment against an outermost workpiece, which is positioned on an outermost portion of the stacked body and against which the first welding tip in abutment; carrying out resistance welding on the stacked body by conducting an electric current between the first welding tip and the second welding tip, and causing a branching current to flow from the first welding tip to the auxiliary electrode, or to flow from the auxiliary electrode to the first welding tip; electrically insulating the first welding tip and the auxiliary electrode from each other and stopping flow of the branching current, while continuing conduction of the electric current between the first welding tip and the second welding tip; and stopping conduction of electric current between the first welding tip and the second welding tip, wherein a time from start of conduction of an electric current between the first welding tip and the second welding tip until stopping conduction of the electric current is controlled by a welding timer, and the welding timer sends an electrical conduction start signal to a branching current timer, and wherein the branching current timer carries out a control to initiate measurement of time from receipt of the electrical conduction start signal, and to stop the branching current when a predetermined set time is reached. ### Claim 5 (depends on 4) The resistance welding method according to claim 4, wherein the branching current is stopped by causing only the auxiliary electrode to separate away from the outermost workpiece, or by cutting off only an electrical path between the auxiliary electrode and a power source. ### Claim 6 A resistance welding method for carrying out resistance welding with respect to a stacked body formed by stacking a plurality of workpieces, comprising the steps of: sandwiching the stacked body between a first welding tip and a second welding tip, and bringing an auxiliary electrode having a polarity opposite to that of the first welding tip abutment against an outermost workpiece, which is positioned on an outermost portion of the stacked body and against which the first welding tip is in abutment; carrying out resistance welding on the stacked body by conducting an electric current between the first welding tip and the second welding tip, and causing a branching current to flow from the first welding tip to the auxiliary electrode, or to flow from the auxiliary electrode to the first welding tip; and electrically insulating the first welding tip and the auxiliary electrode from each other and stopping flow of the branching current when a slope of a conduction time vs. temperature graph of the outermost workpiece changes from a large slope to a small slope. ### Claim 7 (depends on 6) The resistance welding method according to claim 6, wherein the branching current is stopped by causing only the auxiliary electrode to separate away from the outermost workpiece, or by cutting off only an electrical path between the auxiliary electrode and a power source. ### Claim 8 A resistance welding device for carrying out resistance welding with respect to a stacked body formed by stacking a plurality of workpieces, comprising: a first welding tip and a second welding tip that sandwich the stacked body therebetween; a pressing member that abuts against an outermost workpiece, which is positioned on an outermost portion of the stacked body, at a region thereof that differs from a region where the first welding tip is in abutment, for thereby pressing the stacked body from a side of the outermost workpiece; and a pressing mechanism for generating a pressing force on the pressing member. ### Claim 9 (depends on 8) The resistance welding device according to claim 8, further comprising a robot supporting a welding gun on which the first welding tip and the second welding tip are disposed, and the pressing mechanism also being disposed on the welding gun. ### Claim 10 (depends on 8) The resistance welding device according to claim 8, wherein the pressing member comprises an auxiliary electrode having a polarity opposite to that of the first welding tip, such that when an electric current is conducted between the first welding tip and the second welding tip, a branching current is made to flow either from the first welding tip to the auxiliary electrode, or from the auxiliary electrode to the first welding tip. ### Claim 11 (depends on 10) The resistance welding device according to claim 10, further comprising another auxiliary electrode, which is provided on a side of the second welding tip and has a polarity opposite to that of the second welding tip, such that after either the branching current that flows from the first welding tip to the auxiliary electrode or the branching current that flows from the auxiliary electrode to the first welding tip has vanished, a branching current is made to flow either from the other auxiliary electrode to the second welding tip, or from the second welding tip the other auxiliary electrode. ### Claim 12 A resistance welding device for carrying out resistance welding with respect to a stacked body formed by stacking a plurality of workpieces, comprising: a first welding tip and a second welding tip that sandwich the stacked body therebetween; an auxiliary electrode that abuts against an outermost workpiece, which is positioned on an outermost portion of the stacked body together with the first welding tip, and having a polarity opposite to that of the first welding tip; a welding timer that controls a time of conduction of electric current when current is conducted between the first welding tip and the second welding tip, which sandwich the stacked body therebetween for carrying out resistance welding thereon; a branching current timer, which when the current is conducted, controls a time during which a branching current flows from the first welding tip to the auxiliary electrode, or flows from the auxiliary electrode to the first welding tip; and a control circuit that sends an electrical conduction start signal to the welding timer, and inputs to the branching current timer a time at which the branching current flows, wherein, by operation of the welding timer to which the electrical conduction start signal was sent, the electrical conduction start signal is sent to the branching current timer simultaneously with start of electrical conduction between the first welding tip and the second welding tip. ### Claim 13 (depends on 12) The resistance welding device according to claim 12, wherein between the auxiliary electrode and a power source, a switch is provided, which connects or interrupts only an electrical path between the auxiliary electrode and the power source. ### Claim 14 (depends on 12) The resistance welding device according to claim 12, further comprising a displacement mechanism for causing only the auxiliary electrode to approach toward or separate away from the outermost workpiece. ### Claim 15 (depends on 12) The resistance welding device according to claim 12, wherein the auxiliary electrode is of an annular shape that surrounds the first welding tip. ### Claim 16 A resistance welding device for carrying out resistance welding with respect to a stacked body formed by stacking a plurality of workpieces, comprising: a first welding tip and a second welding tip that sandwich the stacked body therebetween; an auxiliary electrode that abuts against an outermost workpiece, which is positioned on an outermost portion of the stacked body together with the first welding tip, and having a polarity opposite to that of the first welding tip; and a control circuit, which when resistance welding is carried out by conducting an electric current between the first welding tip and the second welding tip that sandwich the stacked body therebetween, controls a time during which a branching current flows from the first welding tip to the auxiliary electrode, or flows from the auxiliary electrode to the first welding tip, wherein the control circuit electrically insulates the first welding tip and the auxiliary electrode from each other and stops flow of the branching current when a slope of a conduction time vs. temperature graph of the outermost workpiece changes from a large slope to a small slope. ### Claim 17 (depends on 16) The resistance welding device according to claim 16, wherein between the auxiliary electrode and a power source, a switch is provided, which connects or interrupts only an electrical path between the auxiliary electrode and the power source. ### Claim 18 (depends on 16) The resistance welding device according to claim 16, further comprising a displacement mechanism for causing only the auxiliary electrode to approach toward or separate away from the outermost workpiece. ### Claim 19 (depends on 16) The resistance welding device according to claim 16, wherein the auxiliary electrode is of an annular shape that surrounds the first welding tip.