WO2024171943A1 - Resistance spot welding device, and resistance spot welding method - Google Patents

Resistance spot welding device, and resistance spot welding method Download PDF

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Publication number
WO2024171943A1
WO2024171943A1 PCT/JP2024/004345 JP2024004345W WO2024171943A1 WO 2024171943 A1 WO2024171943 A1 WO 2024171943A1 JP 2024004345 W JP2024004345 W JP 2024004345W WO 2024171943 A1 WO2024171943 A1 WO 2024171943A1
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Prior art keywords
spot welding
pair
electrode
resistance spot
mass
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PCT/JP2024/004345
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French (fr)
Japanese (ja)
Inventor
陽一朗 下田
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株式会社神戸製鋼所
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Publication of WO2024171943A1 publication Critical patent/WO2024171943A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • 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
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/10—Spot welding; Stitch welding
    • B23K11/11—Spot welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • 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
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/16—Resistance welding; Severing by resistance heating taking account of the properties of the material to be welded
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • 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
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/30—Features relating to electrodes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon

Definitions

  • the present invention relates to a resistance spot welding device and a resistance spot welding method.
  • HTSS high tensile strength steel
  • resistance spot welding is mainly used for assembling automobile bodies and attaching parts, and is also applied to welding of high tensile strength steel.
  • Patent Document 1 discloses a resistance spot welding method that includes a welding process in which a current is passed while a welding electrode applies a pressure of F1, and a cooling process in which a pressure of F2 is maintained immediately after the current is stopped, and the pressure satisfies the relationship F2 > F1 x 2, making it possible to suppress LME cracking.
  • Patent Document 2 discloses a resistance spot welding method that can suppress LME cracking by appropriately controlling the time that the pressure is held after the current flow is stopped.
  • Patent Document 3 discloses a spot welding machine in which a flanged rod is inserted into a cylindrical socket screwed into the base member of one of the electrodes, and a convex spherical seat provided at the base end of the flanged rod is abutted against the receiving surface of the base member.
  • the center of oscillation of the convex spherical seat of the flanged rod is located approximately near the center of the flanged rod, and LME cracking is suppressed by limiting the amount of shift from the original position of the electrode tip provided at the tip of the flanged rod.
  • Patent Document 4 discloses an electrode for a spot welding gun in which a first electrode shank with an electrode tip at one end is connected to a second electrode shank by an elastically deformable connecting member, and when the electrode tip comes into contact with the steel plate in an inclined state, the connecting member elastically deforms to keep the angle between the electrode and the steel plate perpendicular, thereby suppressing LME cracking.
  • Patent Document 5 discloses a resistance spot welding method that can suppress LME cracking by clamping multiple steel plates using a pair of electrodes equipped with an elastic member that constitutes an angle correction mechanism that can correct the angle of the electrode tip relative to the steel plate, and passing current while applying pressure while the electrode tip is in contact with the steel plate approximately perpendicularly.
  • Japanese Patent Application Publication No. 2019-171450 International Publication No. 2017/033455 Microfilm of Japanese Utility Model Application No. 58-168076 (Japanese Utility Model Application No. 60-74871) Japanese Utility Model Registration No. 3226182 Japanese Patent Application Publication No. 2022-21770
  • the electrode tip of the electrode is made oscillating, which suppresses the impact angle of the upper and lower electrodes against the steel plate, reduces tensile stress, and suppresses LME cracking.
  • the welding guns described in Patent Documents 4 and 5 connect a pair of electrode shanks with an elastically deformable connecting member (spring) to correct the impact angle of the electrode tip against the steel plate even when the steel plate is tilted relative to the axis of the electrode, thereby suppressing misalignment of the axis of the pair of electrode tips.
  • an elastically deformable connecting member spring
  • the present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a resistance spot welding device and a resistance spot welding method that can correct the impact angle of the electrode tip on the steel plate even when the steel plate is tilted relative to the axis of the electrode, can immediately align a universal joint that has been bent to correct the impact angle in a straight line, and has a compact electrode.
  • the above object of the present invention is achieved by the following configuration [1] of a resistance spot welding device.
  • a pair of electrodes each having an electrode tip that sandwiches a plurality of steel plates; an angle correction mechanism provided on at least one of the pair of electrodes and capable of correcting an angle of the electrode tip with respect to the steel plate; a resistance spot welding device for spot welding the plurality of steel plates by sandwiching the plurality of steel plates between the pair of electrode tips and passing current through the pair of electrode tips while applying a pressure to the pair of electrode tips,
  • the angle correction mechanism includes a pair of universal joints each having an engaging portion having a convex spherical tip end and an engaged portion having a concave spherical tip end into which the engaging portion is slidably fitted
  • the pair of universal joints include a pair of first shaft portions having the engaging portions, a second shaft portion having portions of both engaged portions at both axial ends, and a pair of cover members attached to both axial ends of the second shaft portion and having remaining portions of both engaged portions, At least the pair of first shaft portions and the second shaft portion are made of a conductive material,
  • the electrode has
  • a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
  • the resistance spot welding device of the present invention can correct the impact angle of the electrode tip against the steel plate even if the steel plate is tilted relative to the axis of the electrode, and can form a compact electrode that can immediately align a universal joint that has been bent to correct the impact angle.
  • the resistance spot welding method of the present invention when resistance spot welding multiple steel plates including zinc-based plated steel plates and high-tensile steel plates, or multiple steel plates including zinc-based plated high-tensile steel plates, it is possible to suppress the occurrence of LME cracks in the pressure welded joints of resistance spot welded joints.
  • FIG. 1 is a side view of a resistance spot welding apparatus according to a first embodiment of the present invention.
  • FIG. 2 is a perspective view of the electrode shown in FIG.
  • FIG. 3 is a side view of the electrode shown in FIG.
  • FIG. 4A is a vertical cross-sectional view of the electrode shown in FIG.
  • FIG. 4B is a vertical cross-sectional view illustrating the flow of cooling water in the electrode tip shown in FIG. 4A.
  • FIG. 5(a) is a side view of an electrode that has been bent so as to be approximately perpendicular to an inclined steel plate and has had the strike angle corrected
  • FIG. 5(b) is a vertical cross-sectional view of a portion surrounded by a circle A shown in FIG. 5(a).
  • FIG. 5(a) is a side view of an electrode that has been bent so as to be approximately perpendicular to an inclined steel plate and has had the strike angle corrected
  • FIG. 5(b) is a vertical cross-sectional view of a portion
  • FIG. 6(a) is a side view of an electrode whose strike angle has been corrected so as to be approximately perpendicular to an inclined steel plate
  • FIG. 6(b) is a vertical cross-sectional view of FIG. 6(a).
  • FIG. 7 is a side view of an electrode of a resistance spot welding apparatus according to a second embodiment of the present invention. 8 is a longitudinal sectional view and an enlarged view of a main portion of the electrode shown in FIG.
  • FIG. 9 is a vertical cross-sectional view of an electrode that has been bent so as to be approximately perpendicular to an inclined steel plate and has had its strike angle corrected.
  • the resistance spot welding device of this embodiment is for spot welding multiple metal plates (steel plates), but is particularly suitable for spot welding multiple steel plates M including at least one steel plate containing 0.08% by mass or more of C and 0.50% by mass or more of Si, having a tensile strength of 980 MPa or more, and having zinc-based plating (i.e., high-tensile steel plate with zinc-based plating).
  • the resistance spot welding device of this embodiment is also suitable for spot welding multiple steel plates M including a normal zinc-based plated steel plate such as mild steel with zinc-based plating, and a high-tensile steel plate with no zinc-based plating that is in contact with the normal zinc-based plated steel plate and contains 0.08% by mass or more of C and 0.50% by mass or more of Si, has a tensile strength of 980 MPa or more, and is in contact with the normal zinc-based plated steel plate.
  • a normal zinc-based plated steel plate such as mild steel with zinc-based plating
  • a high-tensile steel plate with no zinc-based plating that is in contact with the normal zinc-based plated steel plate and contains 0.08% by mass or more of C and 0.50% by mass or more of Si, has a tensile strength of 980 MPa or more, and is in contact with the normal zinc-based plated steel plate.
  • Examples of steel sheets that have been subjected to zinc-based plating include galvannealed steel sheets (GA), hot-dip galvanized steel sheets (GI), and electrolytic galvanized steel sheets (EG).
  • a resistance spot welding device 10 includes a frame 11 having a substantially C-shaped shape in a plan view, a pressure cylinder 12 provided at one end of the frame 11, two bases 13A and 13B provided at opposing ends of the frame 11 and the pressure cylinder 12, a movable electrode 20 provided on the movable base 13A, and a fixed electrode 20 provided on the fixed base 13B.
  • the movable electrode 20 and the fixed electrode 20 are arranged so as to face each other on the same axis.
  • the electrode 20 includes a pair of universal joints 30 that are angle correction mechanisms, a pair of magnetic mechanisms 15 provided on each of the pair of universal joints 30, an electrode tip 70 that contacts the steel plate M, and a fixing portion 14 for mounting to the bases 13A and 13B.
  • each of the pair of universal joints 30 has a first shaft portion 31, a second shaft portion 32, and a cover member 33, which are assembled together.
  • the pair of universal joints 30 have the same configuration, being symmetrical above and below the axial middle portion of the second shaft portion 32, with the second shaft portion 32 being a common single member, and the pair of magnetic mechanisms 15 also have the same configuration above and below the axial middle portion of the second shaft portion 32.
  • the first shaft portion 31 is a columnar member with a through hole 34 formed therethrough in the axial direction, with an engagement portion 35 formed with a convex spherical outer shape at one end and a tapered portion 36 at the other end.
  • a male thread portion 37 is formed on the outer peripheral surface of the axially middle portion of the first shaft portion 31, and a female thread portion 43 is formed at the other end of the through hole 34 (i.e., the tapered portion 36 side).
  • An electrode tip 70 is fixed to the tapered portion 36 of one of the first shaft portions 31 arranged on the steel plate M side, and a fixed portion 14 is fixed to the tapered portion 36 of the other first shaft portion 31 arranged on the pressure cylinder 12 side.
  • a male thread 14a formed on the fixed portion 14 is screwed into a female thread (not shown) of the base 13A and fixed to the base 13A.
  • the second shaft portion 32 is a columnar member whose outer diameter is larger than that of the first shaft portion 31, has a through hole 38 penetrating in the axial direction, and has hemispherical recesses 39a formed into concave spherical shapes at both axial end portions.
  • a plurality of female threads 40 are provided at equal intervals in the circumferential direction on both axial end surfaces of the second shaft portion 32.
  • the inner diameter of the through hole 38 is formed to be slightly larger than the inner diameter of the through hole 34 of the first shaft portion 31 .
  • the cover member 33 is a disk-shaped member having an outer diameter approximately equal to that of the second shaft portion 32, and has a hole 41 having the same radius of curvature as the hemispherical recess 39a of the second shaft portion 32, and a concave spherical hemispherical recess 39b formed in a portion thereof.
  • the shaft portion of the first shaft portion 31 is then inserted into the hole 41 of the cover member 33, and the hemispherical recess 39b of the cover member 33 is fitted into a portion of the engagement portion 35 of the first shaft portion 31, and the remaining portion of the engagement portion 35 is fitted into the hemispherical recess 39a of the second shaft portion 32, and the screw 42 is screwed into the female thread portion 40 to fix the cover member 33 to both axial ends of the second shaft portion 32.
  • the hemispherical recess 39b of the cover member 33 and the hemispherical recess 39a of the second shaft portion 32 form the concave spherical engaged portion 39.
  • the convex spherical engaging portion 35 fits freely into the concave spherical engaged portion 39. That is, a pair of universal joints 30 are formed at both axial ends of the second shaft portion 32, into which the first shaft portion 31 fits freely in a rotatable manner. Note that the universal joint 30 is configured so that when the first shaft portion 31 bends relative to the second shaft portion 32, the shaft portion of the first shaft portion 31 interferes with the hole portion 41 of the cover member 33, preventing the universal joint 30 from bending beyond a predetermined angle.
  • the through holes 34, 34 of the pair of first shaft portions 31 and the through hole 38 of the second shaft portion 32 are connected, and a flexible tube 49, such as a vinyl tube, is inserted through the through holes 34, 38, and 34.
  • the male threaded portion 44a of the tube holder 44 screws into the female threaded portion 43 formed in the through hole 34 of the first shaft portion 31, fixing the tube holder 44 to the first shaft portion 31.
  • the tube holder 44 is a generally pipe-shaped member having a through hole 44b that passes through in the axial direction, and has a tapered portion 45 at its tip. Both ends of the tube 49 are watertightly fitted into the tapered portion 45 of the tube holder 44.
  • a tube 48 made of Teflon (registered trademark) or the like is inserted through the tube 49. That is, the tubes 48, 49 are inserted doubly through the through holes 34, 34 of the pair of first shaft portions 31 and the through hole 38 of the second shaft portion 32, and cooling water, which will be described later, can be supplied to the inside of the tube 48 and the annular portion between the tubes 48 and 49.
  • the tubes 48 and 49 form a flow path T for cooling the electrode tip 70.
  • the tube 48 forms the outgoing path T1
  • the annular space between the tubes 48 and 49 forms the return path T2.
  • the cooling water is supplied from the main body of the spot welding machine (not shown) and sent from the fixed part side to the outgoing path T1, and flows in the direction of the arrow shown in FIG. 4A. After cooling the electrode tip 70, it passes through the return path T2 and is returned to the main body of the spot welding machine.
  • the tube 49 is flexible, and the tube 48 is inserted into the tube 49 with a margin, so that the first shaft portion 31 and the second shaft portion 32 can be bent without any hindrance, as described later.
  • the pair of magnetic mechanisms 15 of the electrode 20 is composed of a first magnet 50A fixed to the first shaft portion 31 and a second magnet 50B fixed to the second shaft portion 32 via a cover member 33.
  • the mutually facing surfaces 51A, 51B of the first and second magnets 50A, 50B are magnetized to the same pole, for example, N pole and N pole, or S pole and S pole.
  • the first magnet 50A is a substantially annular magnet, and is screwed and fixed to a substantially disk-shaped magnet holder 52 that screws into the male thread portion 37 of the first shaft portion 31.
  • the second magnet 50B is a substantially annular magnet having the same outer diameter as the first magnet 50A, and is fastened and fixed to the first shaft portion 31 side of the cover member 33 by a screw 42.
  • the pair of electrodes 20 correct the impact angle with respect to the steel sheet M through the action of the pair of universal joints 30, and the movable and fixed electrode tips 70, 70 contact the steel sheet M in a substantially perpendicular state.
  • the pair of universal joints 30 of the electrode 20 below the steel plate M rotates the first shaft portion 31 on the side having the electrode tip 70 counterclockwise relative to the second shaft portion 32, and at the same time, the second shaft portion 32 rotates clockwise, which is the opposite direction to the rotational direction of the first shaft portion 31, and bends into an approximately dogleg shape, so that the electrode tip 70 comes into contact with the steel plate M approximately perpendicularly.
  • the electrode tips 70, 70 that clamp the steel sheet M from above and below rotate slightly so as to contact the steel sheet M approximately perpendicularly, so a slight deviation ⁇ (see FIG. 5(b)) may occur between the axes Y1, Y2 of the electrode tips 70, 70.
  • a deviation ⁇ is slight and does not substantially affect the welding quality, making it possible to achieve good spot welding.
  • substantially perpendicular means an angle that is industrially achievable, and an angle error of, for example, 90° ⁇ 5° is permitted.
  • the first and second magnets 50A, 50B on the fixed side have a larger gap C1 on the right side in the figure and a smaller gap C2 on the left side in the figure.
  • the first and second magnets 50A, 50B on the electrode tip 70 side have a smaller gap C3 on the right side in the figure and a larger gap C4 on the left side in the figure.
  • the magnitude of the repulsive force between the first magnet 50A and the second magnet 50B is inversely proportional to the square of the distance, so the magnitude of the repulsive force acting between the first and second magnets 50A, 50B on the fixed side is greater on the left side of the figure than on the right side of the figure. For example, if the gap C1 is doubled, the magnitude of the repulsive force becomes 1/4, and if the gap C2 is halved, the magnitude of the repulsive force becomes 4 times.
  • the magnitude of the repulsive force acting between the first and second magnets 50A, 50B on the electrode tip 70 side is such that the repulsive force acting on the right side of the figure is greater than the repulsive force acting on the left side of the figure.
  • the difference in magnitude of the repulsive forces on the left and right sides in this diagram acts to return the tilted first and second magnets 50A, 50B to parallel alignment, i.e., to align the bent first shaft portion 31 and second shaft portion 32 in a straight line.
  • the tilted first and second magnets 50A, 50B can be immediately aligned in a straight line before the next welding, resulting in high welding quality and improved welding efficiency.
  • first shaft portion 31, the second shaft portion 32, and the cover member 33 are each made of a conductive material, such as a metal (alloy) such as brass, and act as a conductive path for the welding current.
  • a conductive material such as a metal (alloy) such as brass
  • the radius of curvature R of the tip surface of the electrode tip 70 is 40 mm or more (R ⁇ 40 mm), and the diameter (outer diameter) ⁇ of the tip surface is 16 mm or less ( ⁇ 16 mm) (see FIG. 4A ). This prevents the electrode tip 70 from contacting the steel sheet M on one side, ensuring reliable contact.
  • the electrode tip 70 is formed into a convex curved shape from its tip surface to its outer diameter surface, but it may be formed into a cylindrical shape in which the tip surface and the outer diameter surface are continuous via a chamfer.
  • the pair of universal joints 30 of this embodiment act as an angle correction mechanism capable of correcting the angle of the electrode tip 70 relative to the steel sheet M, correcting the impact angle of the electrode tip 70 and suppressing the misalignment of the electrode tip 70 relative to the steel sheet M.
  • the pair of upper and lower electrode tips 70, 70 abut against the steel sheet M in a state where they are approximately perpendicular to the steel sheet M and where misalignment is suppressed, thereby reducing tensile stress and suppressing LME cracking.
  • the electrode 20 is equipped with a magnetic mechanism 15 consisting of first and second magnets 50A, 50B whose opposing surfaces are magnetized to the same polarity, so that the first shaft portion 31 and the second shaft portion 32 of the universal joint 30, which are bent by the magnetic force (repulsive force) of the first and second magnets 50A, 50B, can be aligned in a straight line, and a compact electrode 20 can be constructed.
  • At least one pair of the first shaft portion 31 and the second shaft portion 32 are formed from a conductive material, eliminating the need for a dedicated conductive member to supply welding current to the electrode tip 70, making the electrode 20 even more compact, and making it possible to easily weld narrow areas without risking any hindrance when welding narrow areas.
  • the pair of universal joints 30, 30 are integrally constructed from the first shaft portion 31, the second shaft portion 32, and the cover member 33, all of which are rigid bodies, so the electrode 20 has high rigidity in the axial direction, and even if a load acts on the electrode 20 from the steel plate M during welding, the axial position can be maintained at a constant position, making it possible to perform stable resistance spot welding.
  • a resistance spot welding device of a second embodiment will be described with reference to Figures 7 to 9.
  • a cylindrical sleeve 55 is fitted and fixed around the second shaft portion 32 of the electrode 20.
  • the sleeve 55 has an axial length that is longer than the combined length of the second shaft portion 32 and the pair of cover members 33, and is provided with male thread portions 56 at both axial ends of the outer circumferential surface.
  • an approximately circular first magnet 50A with a conical outer peripheral surface 51A and an approximately circular second magnet 50B with a conical inner peripheral surface 51B are used.
  • the first magnet 50A has a female thread 57 in the center, which is screwed into the male thread 37 of the first shaft 31 to fix it to the first shaft 31. This allows the position of the first magnet 50A to be adjusted in the vertical direction in the figure.
  • the second magnet 50B has an outer diameter larger than the outer diameter of the sleeve 55, and a female threaded portion 60 is formed at one end of the second magnet 50B.
  • the second magnet 50B is fixed to both ends of the sleeve 55 by having the female threaded portion 60 screwed into the male threaded portion 56 of the sleeve 55.
  • the conical outer surface 51A of the first magnet 50A and the conical inner surface 51B of the second magnet 50B are magnetized with the same polarity and arranged opposite each other, and a repulsive force due to the magnetic forces of the first and second magnets 50A and 50B acts between the conical outer surface 51A and the conical inner surface 51B.
  • the pair of universal joints 30 rotate such that the first shaft portion 31 on the side having the electrode tip 70 rotates counterclockwise relative to the second shaft portion 32, and at the same time, the second shaft portion 32 rotates clockwise, which is the opposite direction to the rotational direction of the first shaft portion 31, and bends into an approximately L-shape.
  • the gap between the conical outer surface 51A of the first magnet 50A and the conical inner surface 51B of the second magnet 50B of the magnetic mechanism 15 on the fixed side is larger at the right side of the figure, and smaller at the left side of the figure, C2.
  • the gap between the conical outer surface 51A of the first magnet 50A and the conical inner surface 51B of the second magnet 50B of the magnetic mechanism 15 on the electrode tip 70 side is smaller at the right side of the figure, and larger at the left side of the figure, C3.
  • a repulsive force corresponding to the gaps C1, C2, C3, and C4 acts between the first magnet 50A and the second magnet, aligning the first shaft portion 31 and the second shaft portion 32 of the bent universal joint 30 in a straight line.
  • Other configurations and operations are similar to those of the resistance spot welding device 10 of the first embodiment.
  • the resistance spot welding device and the resistance spot welding method according to the first and second embodiments have been described, but the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. are possible as appropriate.
  • an engaging portion is provided on the first shaft portion and an engaged portion is provided on the second shaft portion, but the opposite may be true, with an engaged portion provided on the first shaft portion and an engaging portion provided on the second shaft portion.
  • the pair of first shaft portions, the second shaft portion, and the pair of cover members are each made of a conductive material, but in the present invention, it is sufficient that at least the pair of first shaft portions and second shaft portions are made of a conductive material.
  • the angle correction mechanism having a pair of universal joints is provided on each of the pair of electrodes, but in the present invention, the angle correction mechanism may be provided on at least one of the pair of electrodes.
  • the bent first and second shaft portions are aligned in a straight line by a magnetic mechanism consisting of magnets whose opposing surfaces are magnetized to the same polarity, but the magnets may be permanent magnets or so-called electromagnets that generate magnetic force by passing a current through a coil. In this case too, the direction of the current is set so that the opposing surfaces have the same polarity.
  • a pair of electrodes each having an electrode tip that sandwiches a plurality of steel plates; an angle correction mechanism provided on at least one of the pair of electrodes and capable of correcting an angle of the electrode tip with respect to the steel plate; a resistance spot welding device for spot welding the plurality of steel plates by sandwiching the plurality of steel plates between the pair of electrode tips and passing current through the pair of electrode tips while applying a pressure to the pair of electrode tips,
  • the angle correction mechanism includes a pair of universal joints each having an engaging portion having a convex spherical tip end and a concave spherical engaged portion into which the engaging portion is slidably fitted,
  • the pair of universal joints include a pair of first shaft portions having the engaging portions, a second shaft portion having portions of both engaged portions at both axial ends, and a pair of cover members attached to both axial ends of the second shaft portion and having remaining portions of both engaged portions, At least the pair of first shaft portions and the second shaft portion are made of a conductive material,
  • the electrode has a magnetic
  • a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Resistance Welding (AREA)

Abstract

Provided is a resistance spot welding device with which it is possible to correct an angle of attack of an electrode tip with respect to a steel plate, even if the steel plate is inclined with respect to the axis of the electrode, and to cause a universal joint that has been bent in order to correct the angle of attack to be aligned immediately in a straight line. A mechanism for correcting the angle of an electrode tip (70) with respect to a steel plate M comprises a pair of universal joints (30) each including an engaging portion (35) in the shape of a convex spherical surface, and an engaged portion (39) in the shape of a concave spherical surface with which the engaging portion (35) slidably mates. The pair of universal joints (30) include: a pair of first shaft portions (31) including the engaging portions (35); a second shaft portion (32) including, at both ends in an axial direction, parts (hemispherical concave portions) (39a) of both engaged portions (39); and a pair of cover members (33) which are attached to both ends, in the axial direction, of the second shaft portion (32), and which include the remaining parts (hemispherical concave portions) (39b) of both engaged portions (39). Further, magnetic mechanisms (15) consist of magnets having mutually-opposing surfaces that are magnetized with the same polarity, and the magnetic mechanisms (15) cause the first shaft portions (31) and the second shaft portion (32) that have been bent to be aligned in a straight line.

Description

抵抗スポット溶接装置及び抵抗スポット溶接方法Resistance spot welding device and resistance spot welding method
　本発明は、抵抗スポット溶接装置及び抵抗スポット溶接方法に関する。 The present invention relates to a resistance spot welding device and a resistance spot welding method.
　近年、ＣＯ２排出量の削減を目的とした車体軽量化や衝突安全性強化を実現するため、自動車のボディ骨格等に高張力鋼板（Ｈｉｇｈ　Ｔｅｎｓｉｌｅ　Ｓｔｒｅｎｇｔｈ　Ｓｔｅｅｌ；ＨＴＳＳ）が広く採用されている。また、自動車の車体の組立や部品の取付けなどでは、主として、抵抗スポット溶接が使用されており、高張力鋼板の溶接にも適用されている。 In recent years, high tensile strength steel (HTSS) has been widely adopted for the body frame of automobiles in order to realize weight reduction of automobile bodies and strengthen collision safety for the purpose of reducing CO2 emissions. Furthermore, resistance spot welding is mainly used for assembling automobile bodies and attaching parts, and is also applied to welding of high tensile strength steel.
　自動車用鋼板には、防錆化の観点から、耐食性に優れた亜鉛系めっきが施された高張力鋼板も多用されている。しかし、亜鉛系めっきが施された高張力鋼板を用いて抵抗スポット溶接を行うと、該溶接箇所の鋼板表面で溶融した亜鉛や、亜鉛と電極の銅との合金が、鋼板の結晶粒界に侵入して粒界強度を低下させる、ＬＭＥ（Ｌｉｑｕｉｄ　Ｍｅｔａｌ　Ｅｍｂｒｉｔｔｌｅｍｅｎｔ）と呼ばれる粒界脆化割れが起きやすいことが知られている。このような割れが生じると、溶接部の強度が低下して抵抗スポット溶接継手の信頼性が低下してしまうことから、施工面での対策が求められている。 For automotive steel sheets, high-tensile steel sheets with zinc-based plating, which has excellent corrosion resistance, are often used from the perspective of rust prevention. However, it is known that when resistance spot welding is performed using zinc-based plated high-tensile steel sheets, the zinc molten on the steel sheet surface at the welded area and the alloy of zinc and copper of the electrode easily penetrate the grain boundaries of the steel sheet, reducing the grain boundary strength, causing grain boundary embrittlement cracking called LME (Liquid Metal Embrittlement). When such cracking occurs, the strength of the welded part decreases and the reliability of the resistance spot welded joint decreases, so measures are required in the construction process.
　例えば、特許文献１には、溶接電極により加圧力Ｆ１で加圧しながら通電する溶接工程と、通電の終了直後から加圧力Ｆ２で保持する冷却工程を備え、加圧力がＦ２＞Ｆ１×２の関係を満足することで、ＬＭＥ割れを抑制可能とした抵抗スポット溶接方法が開示されている。 For example, Patent Document 1 discloses a resistance spot welding method that includes a welding process in which a current is passed while a welding electrode applies a pressure of F1, and a cooling process in which a pressure of F2 is maintained immediately after the current is stopped, and the pressure satisfies the relationship F2 > F1 x 2, making it possible to suppress LME cracking.
　特許文献２には、通電終了後の加圧力保持時間を適宜制御することにより、ＬＭＥ割れを抑制可能とした抵抗スポット溶接方法が開示されている。 Patent Document 2 discloses a resistance spot welding method that can suppress LME cracking by appropriately controlling the time that the pressure is held after the current flow is stopped.
　特許文献３には、一方の電極の基部材に螺合した筒状ソケット内部に鍔付きロッドを挿入し、この鍔付きロッドの基端に設けた凸球面座を、基部材の受面に当接させたスポット溶接機が開示されており、鍔付きロッドの凸球面座の揺動中心が、鍔付きロッドの略中央近くに位置しており、鍔付きロッドの先端部に設けた電極チップの原位置からのシフト量を抑えることで、ＬＭＥ割れを抑制している。 Patent Document 3 discloses a spot welding machine in which a flanged rod is inserted into a cylindrical socket screwed into the base member of one of the electrodes, and a convex spherical seat provided at the base end of the flanged rod is abutted against the receiving surface of the base member. The center of oscillation of the convex spherical seat of the flanged rod is located approximately near the center of the flanged rod, and LME cracking is suppressed by limiting the amount of shift from the original position of the electrode tip provided at the tip of the flanged rod.
　特許文献４には、一方の端部に電極チップが設けられた第１の電極用シャンクが、弾性変形可能な接続部材により第２の電極用シャンクと接続されており、電極チップが鋼板に傾斜した状態で接触したとき、接続部材が弾性変形することで電極と鋼板とのなす角度を垂直に保ち、ＬＭＥ割れを抑制可能としたスポット溶接ガン用電極が開示されている。 Patent Document 4 discloses an electrode for a spot welding gun in which a first electrode shank with an electrode tip at one end is connected to a second electrode shank by an elastically deformable connecting member, and when the electrode tip comes into contact with the steel plate in an inclined state, the connecting member elastically deforms to keep the angle between the electrode and the steel plate perpendicular, thereby suppressing LME cracking.
　特許文献５には、鋼板に対する電極チップの角度を補正可能な角度補正機構を構成する弾性部材を備える一対の電極を用いて複数の鋼板を挟み込み、電極チップを鋼板に対して略垂直に接触させながら、加圧力を付与した状態で通電することで、ＬＭＥ割れを抑制可能とした抵抗スポット溶接方法が開示されている。 Patent Document 5 discloses a resistance spot welding method that can suppress LME cracking by clamping multiple steel plates using a pair of electrodes equipped with an elastic member that constitutes an angle correction mechanism that can correct the angle of the electrode tip relative to the steel plate, and passing current while applying pressure while the electrode tip is in contact with the steel plate approximately perpendicularly.
日本国特開２０１９－１７１４５０号公報Japanese Patent Application Publication No. 2019-171450 国際公開第２０１７／０３３４５５号International Publication No. 2017/033455 日本国実願昭５８－１６８０７６号（日本国実開昭６０－７４８７１号）のマイクロフィルムMicrofilm of Japanese Utility Model Application No. 58-168076 (Japanese Utility Model Application No. 60-74871) 日本国実用新案登録第３２２６１８２号公報Japanese Utility Model Registration No. 3226182 日本国特開２０２２－２１７７０号公報Japanese Patent Application Publication No. 2022-21770
　ここで、特許文献３～５に記載のスポット溶接機及び抵抗スポット溶接方法では、電極の電極チップを揺動可能とすることで、鋼板に対する上下電極の打角を抑制して引張応力を低減させ、ＬＭＥ割れの抑制を図っている。 Here, in the spot welding machine and resistance spot welding method described in Patent Documents 3 to 5, the electrode tip of the electrode is made oscillating, which suppresses the impact angle of the upper and lower electrodes against the steel plate, reduces tensile stress, and suppresses LME cracking.
　しかしながら、特許文献３に記載のスポット溶接機は、電極の軸心に対して鋼板が傾いていると、鍔付きロッドが凸球面座の揺動中心を中心として旋回して打角補正するため、電極チップが鋼板に対してずれを生じ、依然としてＬＭＥ割れが生じる可能性がある。 However, in the spot welding machine described in Patent Document 3, if the steel plate is tilted relative to the axis of the electrode, the flanged rod rotates around the center of oscillation of the convex spherical seat to correct the strike angle, causing the electrode tip to shift relative to the steel plate, and LME cracking may still occur.
　また、特許文献４及び５に記載の溶接ガンは、一対の電極用シャンクを弾性変形可能な接続部材（ばね）で接続して、鋼板が電極の軸心に対して傾いている場合でも、電極チップの鋼板に対する打角を補正し、一対の電極チップの軸心のずれかを抑制している。しかしながら、溶接電流を電極チップに供給する導線が、一対の電極用シャンクの外側に配設されているため、該導線が狭隘部を溶接する際の障害となる場合があり、電極のコンパクト化が求められている。 In addition, the welding guns described in Patent Documents 4 and 5 connect a pair of electrode shanks with an elastically deformable connecting member (spring) to correct the impact angle of the electrode tip against the steel plate even when the steel plate is tilted relative to the axis of the electrode, thereby suppressing misalignment of the axis of the pair of electrode tips. However, because the conductors that supply the welding current to the electrode tips are arranged on the outside of the pair of electrode shanks, the conductors can become an obstacle when welding narrow areas, and there is a demand for more compact electrodes.
　なお、特許文献１及び２に記載のスポット溶接方法は、いずれも電極チップを揺動させる機構を備えておらず、打角が発生した場合にＬＭＥ割れの抑制を図ることについて何ら考慮されていない。 Note that neither of the spot welding methods described in Patent Documents 1 and 2 has a mechanism for oscillating the electrode tip, and no consideration is given to suppressing LME cracking when an impact angle occurs.
　本発明は、前述した課題に鑑みてなされたものであり、その目的は、鋼板が電極の軸心に対して傾いている場合であっても、鋼板に対する電極チップの打角を補正できると共に、打角補正のために屈曲した自在継手を直ちに直線状に整列させることができ、かつ電極のコンパクト化を図った抵抗スポット溶接装置及び抵抗スポット溶接方法を提供することである。 The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a resistance spot welding device and a resistance spot welding method that can correct the impact angle of the electrode tip on the steel plate even when the steel plate is tilted relative to the axis of the electrode, can immediately align a universal joint that has been bent to correct the impact angle in a straight line, and has a compact electrode.
　本発明の上記目的は、抵抗スポット溶接装置に係る下記［１］の構成により達成される。 The above object of the present invention is achieved by the following configuration [1] of a resistance spot welding device.
［１］　複数の鋼板を挟み込む電極チップをそれぞれ備える一対の電極と、
　前記一対の電極の少なくとも一方に設けられ、前記鋼板に対する前記電極チップの角度を補正可能な角度補正機構と、
を備え、前記一対の電極チップによって前記複数の鋼板を挟み込み、前記一対の電極チップに加圧力を付与した状態で通電することで、前記複数の鋼板をスポット溶接する抵抗スポット溶接装置であって、
　前記角度補正機構は、先端部が凸球面状の係合部と、該係合部が摺動自在に嵌合する凹球面状の被係合部とをそれぞれ有する一対の自在継手を備え、
　前記一対の自在継手は、前記係合部を有する一対の第１軸部と、軸方向両端部に前記両被係合部の一部分を有する第２軸部と、前記第２軸部の軸方向両端部に取り付けられ、前記両被係合部の残りの部分を有する一対のカバー部材と、を有し、
　少なくとも前記一対の第１軸部及び前記第２軸部は、導電性材料によって構成され、
　前記電極は、屈曲した前記自在継手の前記第１軸部及び前記第２軸部を直線状に整列可能な磁気的機構を有する、
抵抗スポット溶接装置。 [1] A pair of electrodes each having an electrode tip that sandwiches a plurality of steel plates;
an angle correction mechanism provided on at least one of the pair of electrodes and capable of correcting an angle of the electrode tip with respect to the steel plate;
a resistance spot welding device for spot welding the plurality of steel plates by sandwiching the plurality of steel plates between the pair of electrode tips and passing current through the pair of electrode tips while applying a pressure to the pair of electrode tips,
the angle correction mechanism includes a pair of universal joints each having an engaging portion having a convex spherical tip end and an engaged portion having a concave spherical tip end into which the engaging portion is slidably fitted,
the pair of universal joints include a pair of first shaft portions having the engaging portions, a second shaft portion having portions of both engaged portions at both axial ends, and a pair of cover members attached to both axial ends of the second shaft portion and having remaining portions of both engaged portions,
At least the pair of first shaft portions and the second shaft portion are made of a conductive material,
The electrode has a magnetic mechanism capable of linearly aligning the first shaft portion and the second shaft portion of the bent universal joint.
Resistance spot welding equipment.
また、本発明の上記目的は、抵抗スポット溶接方法に係る下記［２］の構成により達成される。 The above object of the present invention is also achieved by the following configuration [2] relating to the resistance spot welding method.
［２］　上記［１］に記載の抵抗スポット溶接装置を用いて、
　亜鉛系めっきが施された鋼板及びＣ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上の鋼板を含む複数の鋼板、又は、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板を少なくとも１枚有する複数の鋼板、をスポット溶接する抵抗スポット溶接方法。 [2] Using the resistance spot welding device described in [1] above,
Disclosed is a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
　本発明の抵抗スポット溶接装置によれば、鋼板が電極の軸心に対して傾いている場合であっても、電極チップの鋼板に対する打角を補正できると共に、打角補正のために屈曲した自在継手を直ちに直線状に整列させることができるコンパクトな電極を構成できる。 The resistance spot welding device of the present invention can correct the impact angle of the electrode tip against the steel plate even if the steel plate is tilted relative to the axis of the electrode, and can form a compact electrode that can immediately align a universal joint that has been bent to correct the impact angle.
　また、本発明の抵抗スポット溶接方法によれば、亜鉛系めっきが施された鋼板及び高張力鋼板を含む複数の鋼板、又は、亜鉛系めっきが施された高張力鋼板を含む複数の鋼板の抵抗スポット溶接において、抵抗スポット溶接継手の圧接部におけるＬＭＥ割れの発生を抑制できる。 Furthermore, according to the resistance spot welding method of the present invention, when resistance spot welding multiple steel plates including zinc-based plated steel plates and high-tensile steel plates, or multiple steel plates including zinc-based plated high-tensile steel plates, it is possible to suppress the occurrence of LME cracks in the pressure welded joints of resistance spot welded joints.
図１は、本発明の第１実施形態に係る抵抗スポット溶接装置の側面図である。FIG. 1 is a side view of a resistance spot welding apparatus according to a first embodiment of the present invention. 図２は、図１に示す電極の斜視図である。FIG. 2 is a perspective view of the electrode shown in FIG. 図３は、図１に示す電極の側面図である。FIG. 3 is a side view of the electrode shown in FIG. 図４Ａは、図３に示す電極の縦断面図である。FIG. 4A is a vertical cross-sectional view of the electrode shown in FIG. 図４Ｂは、図４Ａに示す電極チップの冷却水の流れを説明する縦断面図である。FIG. 4B is a vertical cross-sectional view illustrating the flow of cooling water in the electrode tip shown in FIG. 4A. 図５（ａ）は、傾いた鋼板に対して略垂直となるように屈曲し、打角補正された電極の側面図であり、図５（ｂ）は、図５（ａ）に示す円Ａで囲む部分の縦断面図である。FIG. 5(a) is a side view of an electrode that has been bent so as to be approximately perpendicular to an inclined steel plate and has had the strike angle corrected, and FIG. 5(b) is a vertical cross-sectional view of a portion surrounded by a circle A shown in FIG. 5(a). 図６（ａ）は、傾いた鋼板に対して略垂直となるように打角補正された電極の側面図であり、図６（ｂ）は、図６（ａ）の縦断面図である。FIG. 6(a) is a side view of an electrode whose strike angle has been corrected so as to be approximately perpendicular to an inclined steel plate, and FIG. 6(b) is a vertical cross-sectional view of FIG. 6(a). 図７は、本発明の第２実施形態に係る抵抗スポット溶接装置の電極の側面図である。FIG. 7 is a side view of an electrode of a resistance spot welding apparatus according to a second embodiment of the present invention. 図８は、図７に示す電極の縦断面図及び要部拡大図である。8 is a longitudinal sectional view and an enlarged view of a main portion of the electrode shown in FIG. 図９は、傾いた鋼板に対して略垂直となるように屈曲し、打角補正された電極の縦断面図である。FIG. 9 is a vertical cross-sectional view of an electrode that has been bent so as to be approximately perpendicular to an inclined steel plate and has had its strike angle corrected.
　以下、本発明に係る抵抗スポット溶接装置及び抵抗スポット溶接方法の各実施形態を図面に基づいて詳細に説明する。 Below, each embodiment of the resistance spot welding device and resistance spot welding method according to the present invention will be described in detail with reference to the drawings.
　なお、本実施形態の抵抗スポット溶接装置は、複数の金属板（鋼板）をスポット溶接するためのものであるが、特に、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板（すなわち、亜鉛系めっきが施された高張力鋼板）を、少なくとも１枚有する複数の鋼板Ｍを、スポット溶接する場合に好適に用いられる。また、本実施形態の抵抗スポット溶接装置は、亜鉛系めっきが施された軟鋼などの通常の亜鉛系めっき鋼板と、該鋼板に接触する、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、亜鉛系めっきなしの高張力鋼板とを有する、複数の鋼板Ｍをスポット溶接する場合にも好適に用いられる。 The resistance spot welding device of this embodiment is for spot welding multiple metal plates (steel plates), but is particularly suitable for spot welding multiple steel plates M including at least one steel plate containing 0.08% by mass or more of C and 0.50% by mass or more of Si, having a tensile strength of 980 MPa or more, and having zinc-based plating (i.e., high-tensile steel plate with zinc-based plating). The resistance spot welding device of this embodiment is also suitable for spot welding multiple steel plates M including a normal zinc-based plated steel plate such as mild steel with zinc-based plating, and a high-tensile steel plate with no zinc-based plating that is in contact with the normal zinc-based plated steel plate and contains 0.08% by mass or more of C and 0.50% by mass or more of Si, has a tensile strength of 980 MPa or more, and is in contact with the normal zinc-based plated steel plate.
　また、亜鉛系めっきが施された鋼板としては、例えば、合金化溶融亜鉛めっき鋼板（ＧＡ）、溶融亜鉛めっき鋼板（ＧＩ）、電気亜鉛めっき鋼板（ＥＧ）などが挙げられる。 Examples of steel sheets that have been subjected to zinc-based plating include galvannealed steel sheets (GA), hot-dip galvanized steel sheets (GI), and electrolytic galvanized steel sheets (EG).
（第１実施形態）
　まず、図１～図６を参照して第２実施形態の抵抗スポット溶接装置について説明する。図１に示すように、本実施形態の抵抗スポット溶接装置１０は、平面視で略Ｃ型の形状を呈するフレーム１１と、フレーム１１の一端に設けられた加圧シリンダ１２と、フレーム１１及び加圧シリンダ１２の対向する端部に設けられた２つの基台１３Ａ，１３Ｂと、可動側の基台１３Ａに設けられた可動側の電極２０と、固定側の基台１３Ｂに設けられた固定側の電極２０を備える。なお、可動側の電極２０及び固定側の電極２０は、同軸上において対向するように配置されている。 First Embodiment
First, a resistance spot welding device according to a second embodiment will be described with reference to Figures 1 to 6. As shown in Figure 1, a resistance spot welding device 10 according to this embodiment includes a frame 11 having a substantially C-shaped shape in a plan view, a pressure cylinder 12 provided at one end of the frame 11, two bases 13A and 13B provided at opposing ends of the frame 11 and the pressure cylinder 12, a movable electrode 20 provided on the movable base 13A, and a fixed electrode 20 provided on the fixed base 13B. The movable electrode 20 and the fixed electrode 20 are arranged so as to face each other on the same axis.
　ここで、スポット溶接を行う場合、重ね合わせた複数（図１では２枚）の被接合体である鋼板Ｍを、可動側の電極２０及び固定側の電極２０間に挿入し、鋼板Ｍを固定側の電極２０に当接させた状態で、加圧シリンダ１２により可動側の電極２０を図中下方へ進出させて、鋼板Ｍを一対の電極２０，２０の間に挟み込む。この状態で加圧しながら一対の電極２０，２０間に通電を行い、スポット溶接を行う。
　なお、可動側の電極２０及び固定側の電極２０は同一構造を有するため、以下の説明では、可動側の電極２０についてのみ説明する。 When spot welding is performed, a plurality of overlapping steel sheets M (two sheets in FIG. 1 ) that are to be joined are inserted between a movable electrode 20 and a fixed electrode 20, and while the steel sheet M is in contact with the fixed electrode 20, the movable electrode 20 is advanced downward in the figure by the pressure cylinder 12, and the steel sheet M is sandwiched between the pair of electrodes 20, 20. In this state, current is passed between the pair of electrodes 20, 20 while pressure is applied, and spot welding is performed.
Since the movable side electrode 20 and the fixed side electrode 20 have the same structure, only the movable side electrode 20 will be described below.
　図２～図４Ｂに示すように、電極２０は、角度補正機構である一対の自在継手３０と、一対の自在継手３０にそれぞれ設けられた一対の磁気的機構１５と、鋼板Ｍに当接する電極チップ７０と、基台１３Ａ，１３Ｂに取付けるための固定部１４と、を備える。 As shown in Figures 2 to 4B, the electrode 20 includes a pair of universal joints 30 that are angle correction mechanisms, a pair of magnetic mechanisms 15 provided on each of the pair of universal joints 30, an electrode tip 70 that contacts the steel plate M, and a fixing portion 14 for mounting to the bases 13A and 13B.
　また、図４Ａに示すように、一対の自在継手３０は、それぞれ第１軸部３１、第２軸部３２及びカバー部材３３を有しており、これらにより一体に組み付けられている。なお、一対の自在継手３０は、第２軸部３２を共通の単一部材として、第２軸部３２の軸方向中間部に対して上下対称で、同一の構成を備えており、一対の磁気的機構１５も、第２軸部３２の軸方向中間部に対して上下に同一の構成を備える。 As shown in FIG. 4A, each of the pair of universal joints 30 has a first shaft portion 31, a second shaft portion 32, and a cover member 33, which are assembled together. The pair of universal joints 30 have the same configuration, being symmetrical above and below the axial middle portion of the second shaft portion 32, with the second shaft portion 32 being a common single member, and the pair of magnetic mechanisms 15 also have the same configuration above and below the axial middle portion of the second shaft portion 32.
　第１軸部３１は、軸方向に貫通する貫通孔３４が形成された柱状部材であり、その一端には外形が凸球面状に形成された係合部３５が設けられ、他端には先細りとなるテーパー部３６が設けられている。また、第１軸部３１の軸方向中間部の外周面には、雄ねじ部３７が形成され、貫通孔３４の他端（すなわち、テーパー部３６側）には、雌ねじ部４３が形成されている。 The first shaft portion 31 is a columnar member with a through hole 34 formed therethrough in the axial direction, with an engagement portion 35 formed with a convex spherical outer shape at one end and a tapered portion 36 at the other end. A male thread portion 37 is formed on the outer peripheral surface of the axially middle portion of the first shaft portion 31, and a female thread portion 43 is formed at the other end of the through hole 34 (i.e., the tapered portion 36 side).
　鋼板Ｍ側に配置される一方の第１軸部３１のテーパー部３６には、電極チップ７０が固定され、加圧シリンダ１２側に配置される他方の第１軸部３１のテーパー部３６には、固定部１４が固定されている。そして、固定部１４に形成された雄ねじ１４ａが、基台１３Ａの不図示の雌ねじに螺合して基台１３Ａに固定されている。 An electrode tip 70 is fixed to the tapered portion 36 of one of the first shaft portions 31 arranged on the steel plate M side, and a fixed portion 14 is fixed to the tapered portion 36 of the other first shaft portion 31 arranged on the pressure cylinder 12 side. A male thread 14a formed on the fixed portion 14 is screwed into a female thread (not shown) of the base 13A and fixed to the base 13A.
　第２軸部３２は、その外径が第１軸部３１の外径よりも大径の柱状部材であり、軸方向に貫通する貫通孔３８を有し、その軸方向両端部には、凹球面状に形成された半球状凹部３９ａが形成されている。また、第２軸部３２の軸方向両端面には、複数の雌ねじ部４０が周方向に等間隔で設けられている。
　なお、本実施形態では、貫通孔３８の内径は、第１軸部３１の貫通孔３４の内径よりも僅かに大きく形成されている。 The second shaft portion 32 is a columnar member whose outer diameter is larger than that of the first shaft portion 31, has a through hole 38 penetrating in the axial direction, and has hemispherical recesses 39a formed into concave spherical shapes at both axial end portions. In addition, a plurality of female threads 40 are provided at equal intervals in the circumferential direction on both axial end surfaces of the second shaft portion 32.
In this embodiment, the inner diameter of the through hole 38 is formed to be slightly larger than the inner diameter of the through hole 34 of the first shaft portion 31 .
　カバー部材３３は、第２軸部３２の外径と略等しい外径を有する円盤状部材であり、第２軸部３２の半球状凹部３９ａと同じ曲率半径を有し、凹球面状の半球状凹部３９ｂが一部に形成された孔部４１を有する。そして、カバー部材３３の孔部４１に第１軸部３１の軸部を挿通し、第１軸部３１の係合部３５の一部分にカバー部材３３の半球状凹部３９ｂを嵌合させた後、係合部３５の残りの部分を第２軸部３２の半球状凹部３９ａに嵌合し、ねじ４２を雌ねじ部４０に螺合してカバー部材３３を第２軸部３２の軸方向両端部に固定する。これにより、カバー部材３３の半球状凹部３９ｂと第２軸部３２の半球状凹部３９ａとは、凹球面状の被係合部３９を形成する。 The cover member 33 is a disk-shaped member having an outer diameter approximately equal to that of the second shaft portion 32, and has a hole 41 having the same radius of curvature as the hemispherical recess 39a of the second shaft portion 32, and a concave spherical hemispherical recess 39b formed in a portion thereof. The shaft portion of the first shaft portion 31 is then inserted into the hole 41 of the cover member 33, and the hemispherical recess 39b of the cover member 33 is fitted into a portion of the engagement portion 35 of the first shaft portion 31, and the remaining portion of the engagement portion 35 is fitted into the hemispherical recess 39a of the second shaft portion 32, and the screw 42 is screwed into the female thread portion 40 to fix the cover member 33 to both axial ends of the second shaft portion 32. As a result, the hemispherical recess 39b of the cover member 33 and the hemispherical recess 39a of the second shaft portion 32 form the concave spherical engaged portion 39.
　したがって、凹球面状の被係合部３９に凸球面状の係合部３５が摺動自在に嵌合する。すなわち、第２軸部３２の軸方向両端部に、第１軸部３１が旋回自在に嵌合する一対の自在継手３０が形成される。なお、自在継手３０は、第２軸部３２に対して第１軸部３１が屈曲したとき、カバー部材３３の孔部４１に第１軸部３１の軸部が干渉することで、所定の角度を超えて屈曲しすぎないように構成されている。 Therefore, the convex spherical engaging portion 35 fits freely into the concave spherical engaged portion 39. That is, a pair of universal joints 30 are formed at both axial ends of the second shaft portion 32, into which the first shaft portion 31 fits freely in a rotatable manner. Note that the universal joint 30 is configured so that when the first shaft portion 31 bends relative to the second shaft portion 32, the shaft portion of the first shaft portion 31 interferes with the hole portion 41 of the cover member 33, preventing the universal joint 30 from bending beyond a predetermined angle.
　また、図４Ａ及び図４Ｂに示すように、一対の第１軸部３１の貫通孔３４，３４と第２軸部３２の貫通孔３８は連通しており、例えば、ビニールチューブなどの柔軟性を有するチューブ４９が貫通孔３４，３８及び３４を貫通して挿通されている。 Also, as shown in Figures 4A and 4B, the through holes 34, 34 of the pair of first shaft portions 31 and the through hole 38 of the second shaft portion 32 are connected, and a flexible tube 49, such as a vinyl tube, is inserted through the through holes 34, 38, and 34.
　また、第１軸部３１の貫通孔３４に形成された雌ねじ部４３には、チューブ押え４４の雄ねじ部４４ａが螺合してチューブ押え４４が第１軸部３１に固定されている。チューブ押え４４は、軸方向に貫通する貫通孔４４ｂを有する略パイプ状部材であり、先端にテーパー部４５を備える。チューブ４９の両端部は、それぞれチューブ押え４４のテーパー部４５に水密に嵌合している。 The male threaded portion 44a of the tube holder 44 screws into the female threaded portion 43 formed in the through hole 34 of the first shaft portion 31, fixing the tube holder 44 to the first shaft portion 31. The tube holder 44 is a generally pipe-shaped member having a through hole 44b that passes through in the axial direction, and has a tapered portion 45 at its tip. Both ends of the tube 49 are watertightly fitted into the tapered portion 45 of the tube holder 44.
　これにより、カバー部材３３の半球状凹部３９ｂと第１軸部３１の係合部３５との間に、冷却水の漏れ防止のためのＯリングなどを設ける必要がなく、Ｏリングを設けた場合と比較して係合部３５と被係合部３９との摺動抵抗が大幅に低減される。 As a result, there is no need to provide an O-ring or the like between the hemispherical recess 39b of the cover member 33 and the engaging portion 35 of the first shaft portion 31 to prevent leakage of cooling water, and the sliding resistance between the engaging portion 35 and the engaged portion 39 is significantly reduced compared to when an O-ring is provided.
　また、テフロン（登録商標）などのチューブ４８がチューブ４９を貫通して挿通されている。すなわち、一対の第１軸部３１の貫通孔３４，３４と第２軸部３２の貫通孔３８には、チューブ４８，４９が２重に挿通され、チューブ４８の内部、及びチューブ４８とチューブ４９の間の円環状部に後述する冷却水が送水可能となっている。 Also, a tube 48 made of Teflon (registered trademark) or the like is inserted through the tube 49. That is, the tubes 48, 49 are inserted doubly through the through holes 34, 34 of the pair of first shaft portions 31 and the through hole 38 of the second shaft portion 32, and cooling water, which will be described later, can be supplied to the inside of the tube 48 and the annular portion between the tubes 48 and 49.
　チューブ４８、４９は、電極チップ７０を冷却するための冷却水の流路Ｔを形成する。具体的には、チューブ４８が往路Ｔ１を形成し、チューブ４８とチューブ４９の間の円環状部の空間が復路Ｔ２を形成する。そして、図示しないスポット溶接機の本体から供給され、固定部側から往路Ｔ１に送られた冷却水は、図４Ａに示す矢印方向に流れ、電極チップ７０を冷却した後、復路Ｔ２を通過して、スポット溶接機の本体へと戻される。なお、チューブ４９は柔軟性を有しており、またチューブ４８は、余裕を持ってチューブ４９内に挿通するため、後述するように、第１軸部３１と第２軸部３２とは、支障なく屈曲可能である。 The tubes 48 and 49 form a flow path T for cooling the electrode tip 70. Specifically, the tube 48 forms the outgoing path T1, and the annular space between the tubes 48 and 49 forms the return path T2. The cooling water is supplied from the main body of the spot welding machine (not shown) and sent from the fixed part side to the outgoing path T1, and flows in the direction of the arrow shown in FIG. 4A. After cooling the electrode tip 70, it passes through the return path T2 and is returned to the main body of the spot welding machine. The tube 49 is flexible, and the tube 48 is inserted into the tube 49 with a margin, so that the first shaft portion 31 and the second shaft portion 32 can be bent without any hindrance, as described later.
　続いて、電極２０の一対の磁気的機構１５は、第１軸部３１に固定された第１の磁石５０Ａと、カバー部材３３を介して第２軸部３２に固定された第２の磁石５０Ｂとで構成されている。第１及び第２の磁石５０Ａ，５０Ｂの互いに対向する面５１Ａ，５１Ｂは、例えば、Ｎ極とＮ極、又はＳ極とＳ極である同極に着磁されている。具体的に、第１の磁石５０Ａは、略円環状の磁石であり、第１軸部３１の雄ねじ部３７に螺合する略円盤状の磁石ホルダ５２に、ねじ固定されている。第２の磁石５０Ｂは、第１の磁石５０Ａと同じ外径寸法を有する略円環状の磁石であり、ねじ４２によりカバー部材３３の第１軸部３１側にカバー部材３３と共締めされて固定されている。 Next, the pair of magnetic mechanisms 15 of the electrode 20 is composed of a first magnet 50A fixed to the first shaft portion 31 and a second magnet 50B fixed to the second shaft portion 32 via a cover member 33. The mutually facing surfaces 51A, 51B of the first and second magnets 50A, 50B are magnetized to the same pole, for example, N pole and N pole, or S pole and S pole. Specifically, the first magnet 50A is a substantially annular magnet, and is screwed and fixed to a substantially disk-shaped magnet holder 52 that screws into the male thread portion 37 of the first shaft portion 31. The second magnet 50B is a substantially annular magnet having the same outer diameter as the first magnet 50A, and is fastened and fixed to the first shaft portion 31 side of the cover member 33 by a screw 42.
　互いに対向する面５１Ａ、５１Ｂが同極に着磁されている第１及び第２の磁石５０Ａ，５０Ｂ間には、対向する面５１Ａ，５１Ｂ間の距離の２乗に反比例する反発力が作用する。該反発力の大きさは、第１軸部３１の雄ねじ部３７に螺合する磁石ホルダ５２を、第１の磁石５０Ａと共に軸方向に移動させて、対向する面５１Ａ，５１Ｂ間の距離を変更することで調整することができる。 A repulsive force acts between the first and second magnets 50A and 50B, whose opposing surfaces 51A and 51B are magnetized to the same polarity, and is inversely proportional to the square of the distance between the opposing surfaces 51A and 51B. The magnitude of the repulsive force can be adjusted by axially moving the magnet holder 52, which screws into the male threaded portion 37 of the first shaft portion 31, together with the first magnet 50A, to change the distance between the opposing surfaces 51A and 51B.
　次に、角度補正機構である一対の自在継手３０の作用について説明する。一対の電極２０は、それぞれ一対の自在継手３０の作用により、鋼板Ｍに対する打角を補正して、可動側及び固定側の両電極チップ７０，７０を鋼板Ｍに対して略垂直状態で接触させる。 Next, we will explain the function of the pair of universal joints 30, which are the angle correction mechanism. The pair of electrodes 20 correct the impact angle with respect to the steel sheet M through the action of the pair of universal joints 30, and the movable and fixed electrode tips 70, 70 contact the steel sheet M in a substantially perpendicular state.
　詳細には、図５（ａ）及び図５（ｂ）のように、電極２０の軸心に対して傾斜している鋼板Ｍに一対の電極２０が接触すると、鋼板Ｍの上方にある電極２０の一対の自在継手３０は、電極チップ７０を有する側の第１軸部３１が、第２軸部３２に対して、図中の反時計方向に回動し、またそれと同時に、第２軸部３２が、第１軸部３１の回転方向と反対方向である、図中の時計方向に回動し、略くの字形に屈曲することで、電極チップ７０が鋼板Ｍに対して略垂直に接触する。 In more detail, as shown in Figures 5(a) and 5(b), when a pair of electrodes 20 contact a steel plate M that is inclined relative to the axis of the electrode 20, the pair of universal joints 30 of the electrode 20 above the steel plate M rotates the first shaft portion 31 on the side having the electrode tip 70 in the counterclockwise direction in the figure relative to the second shaft portion 32, and at the same time, the second shaft portion 32 rotates clockwise in the figure, which is the opposite direction to the rotational direction of the first shaft portion 31, and bends into an approximately dogleg shape, so that the electrode tip 70 contacts the steel plate M approximately perpendicularly.
　また、鋼板Ｍの下方にある電極２０の一対の自在継手３０は、電極チップ７０を有する側の第１軸部３１が、第２軸部３２に対して反時計方向に回動し、またそれと同時に、第２軸部３２が、第１軸部３１の回転方向と反対方向である時計方向に回動して略くの字形に屈曲することで、電極チップ７０が鋼板Ｍに対して略垂直に接触する。 In addition, the pair of universal joints 30 of the electrode 20 below the steel plate M rotates the first shaft portion 31 on the side having the electrode tip 70 counterclockwise relative to the second shaft portion 32, and at the same time, the second shaft portion 32 rotates clockwise, which is the opposite direction to the rotational direction of the first shaft portion 31, and bends into an approximately dogleg shape, so that the electrode tip 70 comes into contact with the steel plate M approximately perpendicularly.
　その際、鋼板Ｍを上下から挟持する電極チップ７０，７０は、鋼板Ｍに対して略垂直に接触するように僅かに回転するため、両電極チップ７０，７０の軸心Ｙ１，Ｙ２には、少しのずれδ（図５（ｂ）参照）が生じ得る。しかしながら、このようなずれδはわずかなものであり、溶接品質に実質的に影響を及ぼすことはなく、良好なスポット溶接を実現することができる。
　なお、ここでいう「略垂直」とは、工業的に達成可能な角度を意味し、例えば、９０°±５°の角度誤差を許容するものとする。 At that time, the electrode tips 70, 70 that clamp the steel sheet M from above and below rotate slightly so as to contact the steel sheet M approximately perpendicularly, so a slight deviation δ (see FIG. 5(b)) may occur between the axes Y1, Y2 of the electrode tips 70, 70. However, such a deviation δ is slight and does not substantially affect the welding quality, making it possible to achieve good spot welding.
In this case, "substantially perpendicular" means an angle that is industrially achievable, and an angle error of, for example, 90°±5° is permitted.
　次に、一対の磁気的機構１５の作用について説明する。図６（ａ）及び図６（ｂ）に示すように、電極２０の軸心に対して傾斜している鋼板Ｍに電極２０が接触すると、一対の自在継手３０は、電極チップ７０を有する側の第１軸部３１が、第２軸部３２に対して、図中の反時計方向に回動し、またそれと同時に、第２軸部３２が、第１軸部３１の回転方向と反対方向である、図中の時計方向に回動して略くの字形に屈曲する。 Next, the action of the pair of magnetic mechanisms 15 will be described. As shown in Figures 6(a) and 6(b), when the electrode 20 comes into contact with the steel plate M that is inclined relative to the axis of the electrode 20, the first shaft portion 31 of the pair of universal joints 30 on the side having the electrode tip 70 rotates counterclockwise in the figure relative to the second shaft portion 32, and at the same time, the second shaft portion 32 rotates clockwise in the figure, which is the opposite direction to the rotational direction of the first shaft portion 31, and is bent into an approximately dogleg shape.
　これにより、固定側（図中上側）の第１及び第２の磁石５０Ａ、５０Ｂは、図中右側の隙間Ｃ１が大きく、図中左側の隙間Ｃ２が小さくなる。同時に、電極チップ７０側（図中下側）の第１及び第２の磁石５０Ａ，５０Ｂは、反対に、図中右側の隙間Ｃ３が小さく、図中左側の隙間Ｃ４が大きくなる。 As a result, the first and second magnets 50A, 50B on the fixed side (upper side in the figure) have a larger gap C1 on the right side in the figure and a smaller gap C2 on the left side in the figure. At the same time, the first and second magnets 50A, 50B on the electrode tip 70 side (lower side in the figure) have a smaller gap C3 on the right side in the figure and a larger gap C4 on the left side in the figure.
　前述したように、第１の磁石５０Ａと第２の磁石５０Ｂ間の反発力の大きさは、距離の２乗に反比例するため、固定側の第１及び第２の磁石５０Ａ，５０Ｂ間に作用する反発力の大きさは、図中左側に作用する反発力が、図中右側に作用する反発力より大きくなる。例えば、隙間Ｃ１が２倍になると、反発力の大きさは１／４になり、隙間Ｃ２が１／２になると、反発力の大きさは４倍になる。 As mentioned above, the magnitude of the repulsive force between the first magnet 50A and the second magnet 50B is inversely proportional to the square of the distance, so the magnitude of the repulsive force acting between the first and second magnets 50A, 50B on the fixed side is greater on the left side of the figure than on the right side of the figure. For example, if the gap C1 is doubled, the magnitude of the repulsive force becomes 1/4, and if the gap C2 is halved, the magnitude of the repulsive force becomes 4 times.
　また同様に、電極チップ７０側の第１及び第２の磁石５０Ａ，５０Ｂ間に作用する反発力の大きさは、図中右側に作用する反発力が、図中左側に作用する反発力より大きくなる。 Similarly, the magnitude of the repulsive force acting between the first and second magnets 50A, 50B on the electrode tip 70 side is such that the repulsive force acting on the right side of the figure is greater than the repulsive force acting on the left side of the figure.
　この図中における左右の反発力の大きさの差は、傾いた第１及び第２の磁石５０Ａ，５０Ｂを平行に戻すように、すなわち、屈曲した第１軸部３１と第２軸部３２を直線状に整列させる力として作用する。 The difference in magnitude of the repulsive forces on the left and right sides in this diagram acts to return the tilted first and second magnets 50A, 50B to parallel alignment, i.e., to align the bent first shaft portion 31 and second shaft portion 32 in a straight line.
　屈曲した第１軸部３１と第２軸部３２を直線状に整列させる作用を弾性部材（ばね）で達成させる場合（上記特許文献４、５参照）と比較すると、ばねで発生する力の大きさは、距離に反比例するのに対して、本実施形態の磁石の反発力は、距離の２乗に反比例するため、大きな力が得られ、短時間で直線状に整列させることができる。さらに、前述したように、係合部３５と被係合部３９間にＯリングを設けた場合と比較すると、本実施形態ではＯリングを用いていないため、係合部３５と被係合部３９間の摺動抵抗が大幅に低減され、さらに短時間で直線状に整列できる。 Compared to using an elastic member (spring) to align the bent first and second shaft portions 31 and 32 in a straight line (see Patent Documents 4 and 5 above), the magnitude of the force generated by a spring is inversely proportional to the distance, whereas the repulsive force of the magnet in this embodiment is inversely proportional to the square of the distance, so a large force can be obtained and linear alignment can be achieved in a short time. Furthermore, as described above, compared to the case where an O-ring is provided between the engaging portion 35 and the engaged portion 39, no O-ring is used in this embodiment, so the sliding resistance between the engaging portion 35 and the engaged portion 39 is significantly reduced and linear alignment can be achieved in an even shorter time.
　このように、整列に要する時間が短縮されるため、鋼板Ｍに複数の溶接部を連続して形成する場合でも、傾いた第１及び第２の磁石５０Ａ，５０Ｂを、次の溶接の前に、直ちに直線状に整列させることができ、高い溶接品質が得られると共に溶接効率が向上する。 In this way, the time required for alignment is reduced, so even when multiple welds are continuously formed on the steel plate M, the tilted first and second magnets 50A, 50B can be immediately aligned in a straight line before the next welding, resulting in high welding quality and improved welding efficiency.
　さらに、直線状に整列した状態では（第１及び第２の磁石５０Ａ，５０Ｂが平行）、特許文献４、５に示すように一対の電極間をばねで接続した場合と比較して、電極間に作用する力（直線状に整列させる力）が周方向で均一になり、安定した溶接品質に寄与する。 Furthermore, when aligned in a straight line (the first and second magnets 50A, 50B are parallel), the force acting between the electrodes (the force that aligns them in a straight line) becomes uniform in the circumferential direction compared to when a pair of electrodes are connected by a spring as shown in Patent Documents 4 and 5, which contributes to stable welding quality.
　また、第１軸部３１、第２軸部３２及びカバー部材３３は、それぞれ導電性を有する、例えば真鍮のような金属（合金）からなる導電性材料により構成されており、溶接電流の導電路として作用する。これにより、例えば特許文献４、５に示すような一対の電極用シャンクの外側に配設された、専用の導電路を別途設ける必要がなく、コンパクトな電極２０を構成できる。 Furthermore, the first shaft portion 31, the second shaft portion 32, and the cover member 33 are each made of a conductive material, such as a metal (alloy) such as brass, and act as a conductive path for the welding current. This makes it possible to configure a compact electrode 20 without the need to separately provide a dedicated conductive path disposed on the outside of a pair of electrode shanks, as shown in Patent Documents 4 and 5, for example.
　電極チップ７０は、その先端面の曲率半径Ｒは４０ｍｍ以上（Ｒ≧４０ｍｍ）となっており、また、その先端面の直径（外径）φが１６ｍｍ以下（φ≦１６ｍｍ）となっている（図４Ａ参照）。これにより、鋼板Ｍに対する電極チップ７０の片当たりが抑制されて確実に接触する。
　なお、本実施形態では、電極チップ７０は、その先端面から外径面にかけて凸曲面状に形成されているが、先端面と外径面とを面取りを介して連続させた円柱状に形成されてもよい。 The radius of curvature R of the tip surface of the electrode tip 70 is 40 mm or more (R≧40 mm), and the diameter (outer diameter) φ of the tip surface is 16 mm or less (φ≦16 mm) (see FIG. 4A ). This prevents the electrode tip 70 from contacting the steel sheet M on one side, ensuring reliable contact.
In this embodiment, the electrode tip 70 is formed into a convex curved shape from its tip surface to its outer diameter surface, but it may be formed into a cylindrical shape in which the tip surface and the outer diameter surface are continuous via a chamfer.
　以上説明したように、本実施形態の一対の自在継手３０は、電極チップ７０の鋼板Ｍに対する角度を補正可能な角度補正機構として作用して、電極チップ７０の打角を補正すると共に、鋼板Ｍに対する電極チップ７０のずれを抑制する。すなわち、上下一対の電極チップ７０，７０は、鋼板Ｍに対して略垂直、かつ、ずれが抑制された状態で鋼板Ｍに当接することで、引張応力を低減させてＬＭＥ割れを抑制する。 As described above, the pair of universal joints 30 of this embodiment act as an angle correction mechanism capable of correcting the angle of the electrode tip 70 relative to the steel sheet M, correcting the impact angle of the electrode tip 70 and suppressing the misalignment of the electrode tip 70 relative to the steel sheet M. In other words, the pair of upper and lower electrode tips 70, 70 abut against the steel sheet M in a state where they are approximately perpendicular to the steel sheet M and where misalignment is suppressed, thereby reducing tensile stress and suppressing LME cracking.
　また、電極２０は、対向する面が同極に着磁された第１及び第２の磁石５０Ａ、５０Ｂで構成された磁気的機構１５を備えるため、第１及び第２の磁石５０Ａ、５０Ｂの磁力（反発力）により屈曲した自在継手３０の第１軸部３１及び第２軸部３２を直線状に整列させることができ、かつコンパクトな電極２０を構成できる。 In addition, the electrode 20 is equipped with a magnetic mechanism 15 consisting of first and second magnets 50A, 50B whose opposing surfaces are magnetized to the same polarity, so that the first shaft portion 31 and the second shaft portion 32 of the universal joint 30, which are bent by the magnetic force (repulsive force) of the first and second magnets 50A, 50B, can be aligned in a straight line, and a compact electrode 20 can be constructed.
　さらに、少なくとも一対の第１軸部３１及び第２軸部３２は、導電性材料で形成されているため、電極チップ７０に溶接電流を供給するための専用の導電部材が不要となり、電極２０がさらにコンパクト化されて、狭隘部の溶接の際にも障害となるおそれはなく、狭隘部を容易に溶接することができる。 Furthermore, at least one pair of the first shaft portion 31 and the second shaft portion 32 are formed from a conductive material, eliminating the need for a dedicated conductive member to supply welding current to the electrode tip 70, making the electrode 20 even more compact, and making it possible to easily weld narrow areas without risking any hindrance when welding narrow areas.
　一対の自在継手３０，３０は、いずれも剛体である第１軸部３１、第２軸部３２及びカバー部材３３で一体的に構成されているため、電極２０は軸方向に対して高い剛性を有しており、溶接時に鋼板Ｍから電極２０に荷重が作用しても軸方向位置を一定位置に維持することができ、安定した抵抗スポット溶接を行い得る。 The pair of universal joints 30, 30 are integrally constructed from the first shaft portion 31, the second shaft portion 32, and the cover member 33, all of which are rigid bodies, so the electrode 20 has high rigidity in the axial direction, and even if a load acts on the electrode 20 from the steel plate M during welding, the axial position can be maintained at a constant position, making it possible to perform stable resistance spot welding.
（第２実施形態）
　次に、図７～図９を参照して第２実施形態の抵抗スポット溶接装置について説明する。本実施形態の抵抗スポット溶接装置１０では、電極２０の第２軸部３２の周囲に、円筒状のスリーブ５５が外嵌固定されている。スリーブ５５は、第２軸部３２及び一対のカバー部材３３の合計長さより長い軸方向長さを有し、外周面の軸方向両端部には、雄ねじ部５６が設けられている。 Second Embodiment
Next, a resistance spot welding device of a second embodiment will be described with reference to Figures 7 to 9. In the resistance spot welding device 10 of this embodiment, a cylindrical sleeve 55 is fitted and fixed around the second shaft portion 32 of the electrode 20. The sleeve 55 has an axial length that is longer than the combined length of the second shaft portion 32 and the pair of cover members 33, and is provided with male thread portions 56 at both axial ends of the outer circumferential surface.
　また、本実施形態では、第１実施形態の平坦な略円環状の第１の磁石５０Ａ及び第２の磁石５０Ｂの代わりに、円錐状の外周面５１Ａを持った略円環状の第１の磁石５０Ａ及び円錐状の内周面５１Ｂを持った略円環状の第２の磁石５０Ｂが用いられている。 In addition, in this embodiment, instead of the flat, approximately circular first magnet 50A and second magnet 50B of the first embodiment, an approximately circular first magnet 50A with a conical outer peripheral surface 51A and an approximately circular second magnet 50B with a conical inner peripheral surface 51B are used.
　第１の磁石５０Ａは、中心に雌ねじ部５７を有し、雌ねじ部５７が第１軸部３１の雄ねじ部３７に螺合して第１軸部３１に固定されている。これにより、第１の磁石５０Ａは、図中上下方向に位置調整が可能である。 The first magnet 50A has a female thread 57 in the center, which is screwed into the male thread 37 of the first shaft 31 to fix it to the first shaft 31. This allows the position of the first magnet 50A to be adjusted in the vertical direction in the figure.
　第２の磁石５０Ｂは、スリーブ５５の外径より大きな外径を有し、第２の磁石５０Ｂの一端には、雌ねじ部６０が形成されている。第２の磁石５０Ｂは、雌ねじ部６０がスリーブ５５の雄ねじ部５６に螺合してスリーブ５５の両端部に固定されている。 The second magnet 50B has an outer diameter larger than the outer diameter of the sleeve 55, and a female threaded portion 60 is formed at one end of the second magnet 50B. The second magnet 50B is fixed to both ends of the sleeve 55 by having the female threaded portion 60 screwed into the male threaded portion 56 of the sleeve 55.
　第１の磁石５０Ａの円錐状の外周面５１Ａと第２の磁石５０Ｂの円錐状の内周面５１Ｂとは、同極に着磁されて対向配置されており、円錐状の外周面５１Ａと円錐状の内周面５１Ｂとの間には、第１及び第２の磁石５０Ａ，５０Ｂの磁力による反発力が作用している。 The conical outer surface 51A of the first magnet 50A and the conical inner surface 51B of the second magnet 50B are magnetized with the same polarity and arranged opposite each other, and a repulsive force due to the magnetic forces of the first and second magnets 50A and 50B acts between the conical outer surface 51A and the conical inner surface 51B.
　そして、電極２０の軸心に対して傾斜している鋼板Ｍに電極２０が接触すると、一対の自在継手３０は、電極チップ７０を有する側の第１軸部３１が、第２軸部３２に対して反時計方向に回動し、またそれと同時に、第２軸部３２が、第１軸部３１の回転方向と反対方向である時計方向に回動して略くの字形に屈曲する。 When the electrode 20 comes into contact with the steel plate M, which is inclined relative to the axis of the electrode 20, the pair of universal joints 30 rotate such that the first shaft portion 31 on the side having the electrode tip 70 rotates counterclockwise relative to the second shaft portion 32, and at the same time, the second shaft portion 32 rotates clockwise, which is the opposite direction to the rotational direction of the first shaft portion 31, and bends into an approximately L-shape.
　これにより、固定側（図中上方）の磁気的機構１５の第１の磁石５０Ａの円錐状の外周面５１Ａと第２の磁石５０Ｂの円錐状の内周面５１Ｂとの隙間は、図中右側の隙間Ｃ１が大きくなり、図中左側の隙間Ｃ２が小さくなる。また、電極チップ７０側（図中下方）の磁気的機構１５の第１の磁石５０Ａの円錐状の外周面５１Ａと第２の磁石５０Ｂの円錐状の内周面５１Ｂとの隙間は、図中右側の隙間Ｃ３が小さくなり、図中左側の隙間Ｃ４が大きくなる。 As a result, the gap between the conical outer surface 51A of the first magnet 50A and the conical inner surface 51B of the second magnet 50B of the magnetic mechanism 15 on the fixed side (upper part of the figure) is larger at the right side of the figure, and smaller at the left side of the figure, C2. Also, the gap between the conical outer surface 51A of the first magnet 50A and the conical inner surface 51B of the second magnet 50B of the magnetic mechanism 15 on the electrode tip 70 side (lower part of the figure) is smaller at the right side of the figure, and larger at the left side of the figure, C3.
　そして、第１の磁石５０Ａと第２の磁石との間には、隙間Ｃ１、Ｃ２、Ｃ３及びＣ４に応じた反発力が作用して、屈曲した自在継手３０の第１軸部３１及び第２軸部３２を直線状に整列させる。
　なお、その他の構成及び作用は、第１実施形態の抵抗スポット溶接装置１０と同様である。 Then, a repulsive force corresponding to the gaps C1, C2, C3, and C4 acts between the first magnet 50A and the second magnet, aligning the first shaft portion 31 and the second shaft portion 32 of the bent universal joint 30 in a straight line.
Other configurations and operations are similar to those of the resistance spot welding device 10 of the first embodiment.
　以上のとおり、第１実施形態及び第２実施形態に係る抵抗スポット溶接装置及び抵抗スポット溶接方法について説明したが、本発明は、前述した実施形態に限定されるものではなく、適宜、変形、改良等が可能である。 As described above, the resistance spot welding device and the resistance spot welding method according to the first and second embodiments have been described, but the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. are possible as appropriate.
　例えば、上記の実施形態では、第１軸部に係合部が設けられ、第２軸部に被係合部が設けられるとしたが、これとは逆に、第１軸部に被係合部を設け、第２軸部に係合部を設けるようにしてもよい。 For example, in the above embodiment, an engaging portion is provided on the first shaft portion and an engaged portion is provided on the second shaft portion, but the opposite may be true, with an engaged portion provided on the first shaft portion and an engaging portion provided on the second shaft portion.
　また、上記の実施形態では、一対の第１軸部、第２軸部及び一対のカバー部材は、それぞれ導電性材料によって構成されるが、本発明においては、少なくとも一対の第１軸部及び第２軸部が導電性材料によって構成されればよい。
　さらに、上記の実施形態では、一対の自在継手を有する角度補正機構は、一対の電極にそれぞれ設けられているが、本発明は、該角度補正機構は、一対の電極の少なくとも一方に設けられてもよい。 In addition, in the above embodiment, the pair of first shaft portions, the second shaft portion, and the pair of cover members are each made of a conductive material, but in the present invention, it is sufficient that at least the pair of first shaft portions and second shaft portions are made of a conductive material.
Furthermore, in the above embodiment, the angle correction mechanism having a pair of universal joints is provided on each of the pair of electrodes, but in the present invention, the angle correction mechanism may be provided on at least one of the pair of electrodes.
　また、上記の実施形態では、互いに対向する面が同極に着磁された磁石で構成された磁気的機構により屈曲した第１軸部及び第２軸部を直線状に整列させたが、磁石は永久磁石であってもよく、またコイルに電流を流すことで磁力を発生させる、いわゆる電磁石であってもよい。この場合も、互いに対向する面が同極になるように、電流の方向が設定される。 In addition, in the above embodiment, the bent first and second shaft portions are aligned in a straight line by a magnetic mechanism consisting of magnets whose opposing surfaces are magnetized to the same polarity, but the magnets may be permanent magnets or so-called electromagnets that generate magnetic force by passing a current through a coil. In this case too, the direction of the current is set so that the opposing surfaces have the same polarity.
　以上のとおり、本明細書には次の事項が開示されている。 As described above, this specification discloses the following:
（１）　複数の鋼板を挟み込む電極チップをそれぞれ備える一対の電極と、
　前記一対の電極の少なくとも一方に設けられ、前記鋼板に対する前記電極チップの角度を補正可能な角度補正機構と、を備え、
　前記一対の電極チップによって前記複数の鋼板を挟み込み、前記一対の電極チップに加圧力を付与した状態で通電することで、前記複数の鋼板をスポット溶接する抵抗スポット溶接装置であって、
　前記角度補正機構は、先端部が凸球面状の係合部と、該係合部が摺動自在に嵌合する凹球面状の被係合部とをそれぞれ有する一対の自在継手を備え、
　前記一対の自在継手は、前記係合部を有する一対の第１軸部と、軸方向両端部に前記両被係合部の一部分を有する第２軸部と、前記第２軸部の軸方向両端部に取り付けられ、前記両被係合部の残りの部分を有する一対のカバー部材と、を有し、
　少なくとも前記一対の第１軸部及び前記第２軸部は、導電性材料によって構成され、
　前記電極は、屈曲した前記自在継手の前記第１軸部及び前記第２軸部を直線状に整列可能な磁気的機構を有する、
抵抗スポット溶接装置。
　この構成によれば、鋼板が電極の軸心に対して傾いている場合であっても、電極チップの鋼板に対する打角を補正できると共に、磁気的機構により打角補正のために屈曲した自在継手を直ちに直線状に整列させることができるコンパクトな電極を構成できる。 (1) A pair of electrodes each having an electrode tip that sandwiches a plurality of steel plates;
an angle correction mechanism provided on at least one of the pair of electrodes and capable of correcting an angle of the electrode tip with respect to the steel plate;
a resistance spot welding device for spot welding the plurality of steel plates by sandwiching the plurality of steel plates between the pair of electrode tips and passing current through the pair of electrode tips while applying a pressure to the pair of electrode tips,
the angle correction mechanism includes a pair of universal joints each having an engaging portion having a convex spherical tip end and a concave spherical engaged portion into which the engaging portion is slidably fitted,
the pair of universal joints include a pair of first shaft portions having the engaging portions, a second shaft portion having portions of both engaged portions at both axial ends, and a pair of cover members attached to both axial ends of the second shaft portion and having remaining portions of both engaged portions,
At least the pair of first shaft portions and the second shaft portion are made of a conductive material,
The electrode has a magnetic mechanism capable of linearly aligning the first shaft portion and the second shaft portion of the bent universal joint.
Resistance spot welding equipment.
With this configuration, even if the steel plate is inclined relative to the axis of the electrode, the impact angle of the electrode tip with respect to the steel plate can be corrected, and a compact electrode can be constructed in which the universal joint that has been bent to correct the impact angle can be immediately aligned in a straight line using the magnetic mechanism.
（２）　前記磁気的機構は、前記第１軸部と、前記第２軸部及び前記カバー部材のうち少なくとも一方との関係において、互いに対向する面が同極に着磁された磁石から構成される、（１）に記載の抵抗スポット溶接装置。
　この構成によれば、互いに対向する面が同極に着磁された磁石に作用する反発力の作用により、溶接時に屈曲した電極を、溶接終了後に直ちに元の直線状態に自動的に復元できる。 (2) The resistance spot welding device according to (1), wherein the magnetic mechanism is composed of magnets whose opposing surfaces are magnetized to the same pole in relation to the first shaft portion and at least one of the second shaft portion and the cover member.
According to this configuration, due to the repulsive force acting on the magnets whose opposing surfaces are magnetized to the same polarity, electrodes that are bent during welding can be automatically restored to their original straight state immediately after welding is completed.
（３）　前記電極チップは、先端面の曲率半径ＲがＲ≧４０ｍｍ、かつ、外径φがφ≦１６ｍｍである、（１）又は（２）に記載の抵抗スポット溶接装置。
　この構成によれば、鋼板に対する電極チップの片当たりが抑制されて電極チップを鋼板に確実に接触できる。 (3) The resistance spot welding device according to (1) or (2), wherein the electrode tip has a tip surface with a radius of curvature R of R≧40 mm and an outer diameter φ of φ≦16 mm.
According to this configuration, uneven contact of the electrode tip with the steel plate is suppressed, and the electrode tip can be reliably brought into contact with the steel plate.
（４）　前記電極は、前記一対の第１軸部の貫通孔と前記第２軸部の貫通孔内を挿通し、前記電極内に冷却水を往復通水可能な２重管が設けられる、（１）～（３）のいずれか１つに記載の抵抗スポット溶接装置。
　この構成によれば、係合部と被係合部の摺動部に水漏れ防止のためのＯリングなどを配設する必要がなく、係合部と被係合部の摺動抵抗を大幅に低減できる。またこれにより、第１軸部及び第２軸部を短時間で直線状に整列できる。 (4) The resistance spot welding device according to any one of (1) to (3), wherein the electrode is inserted through a through hole of the pair of first shaft portions and a through hole of the second shaft portion, and a double pipe through which cooling water can be passed back and forth is provided within the electrode.
With this configuration, there is no need to provide an O-ring or the like to prevent water leakage between the sliding parts of the engaging part and the engaged part, and the sliding resistance between the engaging part and the engaged part can be significantly reduced. This also makes it possible to align the first shaft part and the second shaft part in a straight line in a short time.
（５）　（１）～（４）のいずれか１つに記載の抵抗スポット溶接装置を用いて、
　亜鉛系めっきが施された鋼板及びＣ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上の鋼板を含む複数の鋼板、又は、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板を少なくとも１枚有する複数の鋼板、をスポット溶接する抵抗スポット溶接方法。
　この構成によれば、亜鉛系めっきが施された鋼板及び高張力鋼板を含む複数の鋼板、又は、亜鉛系めっきが施された高張力鋼板を含む複数の鋼板の抵抗スポット溶接において、抵抗スポット溶接継手の圧接部におけるＬＭＥ割れの発生を抑制できる。 (5) Using the resistance spot welding device according to any one of (1) to (4),
Disclosed is a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
According to this configuration, in resistance spot welding of multiple steel plates including a zinc-based plated steel plate and a high-tensile steel plate, or multiple steel plates including a zinc-based plated high-tensile steel plate, the occurrence of LME cracking in the pressure welded portion of a resistance spot welded joint can be suppressed.
　以上、各種の実施の形態について説明したが、本発明はかかる例に限定されないことは言うまでもない。当業者であれば、特許請求の範囲に記載された範疇内において、各種の変更例又は修正例に想到し得ることは明らかであり、それらについても当然に本発明の技術的範囲に属するものと了解される。また、発明の趣旨を逸脱しない範囲において、上記実施の形態における各構成要素を任意に組み合わせてもよい。 Although various embodiments have been described above, it goes without saying that the present invention is not limited to these examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components in the above embodiments may be combined in any manner as long as it does not deviate from the spirit of the invention.
　なお、本出願は、２０２３年２月１５日出願の日本特許出願（特願２０２３－０２１７１８）に基づくものであり、その内容は本出願の中に参照として援用される。 This application is based on a Japanese patent application (Patent Application No. 2023-021718) filed on February 15, 2023, the contents of which are incorporated by reference into this application.
１０　　抵抗スポット溶接装置
１５　　磁気的機構
２０　　電極
３０　　自在継手（角度補正機構）
３１　　第１軸部
３２　　第２軸部
３３　　カバー部材
３５　　係合部
３９　　被係合部
３９ａ、３９ｂ　　　　　　半球状凹部（被係合部）
４８、４９　　チューブ（２重管）
５０Ａ、５０Ｂ　　　　　　磁石
５１Ａ、５１Ｂ　　　　　　磁石の対向する面
７０　　電極チップ
Ｍ　　　鋼板
Ｒ　　　電極チップの先端面の曲率半径
φ　　　電極チップの先端面の外径 10 Resistance spot welding device 15 Magnetic mechanism 20 Electrode 30 Universal joint (angle correction mechanism)
31 First shaft portion 32 Second shaft portion 33 Cover member 35 Engaging portion 39 Engaged portions 39a, 39b Hemispherical recess (engaged portion)
48, 49 Tube (double tube)
50A, 50B Magnets 51A, 51B Opposing surfaces of magnets 70 Electrode tip M Steel plate R Radius of curvature of tip surface of electrode tip φ Outer diameter of tip surface of electrode tip

Claims (9)

  1. 　複数の鋼板を挟み込む電極チップをそれぞれ備える一対の電極と、
    　前記一対の電極の少なくとも一方に設けられ、前記鋼板に対する前記電極チップの角度を補正可能な角度補正機構と、を備え、
    　前記一対の電極チップによって前記複数の鋼板を挟み込み、前記一対の電極チップに加圧力を付与した状態で通電することで、前記複数の鋼板をスポット溶接する抵抗スポット溶接装置であって、
    　前記角度補正機構は、先端部が凸球面状の係合部と、該係合部が摺動自在に嵌合する凹球面状の被係合部とをそれぞれ有する一対の自在継手を備え、
    　前記一対の自在継手は、前記係合部を有する一対の第１軸部と、軸方向両端部に前記両被係合部の一部分を有する第２軸部と、前記第２軸部の軸方向両端部に取り付けられ、前記両被係合部の残りの部分を有する一対のカバー部材と、を有し、
    　少なくとも前記一対の第１軸部及び前記第２軸部は、導電性材料によって構成され、
    　前記電極は、屈曲した前記自在継手の前記第１軸部及び前記第２軸部を直線状に整列可能な磁気的機構を有する、
    抵抗スポット溶接装置。     A pair of electrodes each having an electrode tip that sandwiches a plurality of steel plates;
    an angle correction mechanism provided on at least one of the pair of electrodes and capable of correcting an angle of the electrode tip with respect to the steel plate;
    a resistance spot welding device for spot welding the plurality of steel plates by sandwiching the plurality of steel plates between the pair of electrode tips and passing current through the pair of electrode tips while applying a pressure to the pair of electrode tips,
    the angle correction mechanism includes a pair of universal joints each having an engaging portion having a convex spherical tip end and a concave spherical engaged portion into which the engaging portion is slidably fitted,
    the pair of universal joints include a pair of first shaft portions having the engaging portions, a second shaft portion having portions of both engaged portions at both axial ends, and a pair of cover members attached to both axial ends of the second shaft portion and having remaining portions of both engaged portions,
    At least the pair of first shaft portions and the second shaft portion are made of a conductive material,
    The electrode has a magnetic mechanism capable of linearly aligning the first shaft portion and the second shaft portion of the bent universal joint.
    Resistance spot welding equipment.
  2. 　前記磁気的機構は、前記第１軸部と、前記第２軸部及び前記カバー部材のうち少なくとも一方との関係において、互いに対向する面が同極に着磁された磁石から構成される、請求項１に記載の抵抗スポット溶接装置。 The resistance spot welding device according to claim 1, wherein the magnetic mechanism is composed of magnets whose opposing surfaces are magnetized to the same polarity in relation to the first shaft portion and at least one of the second shaft portion and the cover member.
  3. 　前記電極チップは、先端面の曲率半径ＲがＲ≧４０ｍｍ、かつ、外径φがφ≦１６ｍｍである、請求項１又は２に記載の抵抗スポット溶接装置。 The resistance spot welding device according to claim 1 or 2, wherein the electrode tip has a tip surface with a radius of curvature R of R≧40 mm and an outer diameter φ of φ≦16 mm.
  4. 　前記電極は、前記一対の第１軸部の貫通孔と前記第２軸部の貫通孔内を挿通し、前記電極内に冷却水を往復通水可能な２重管が設けられる、請求項１又は２に記載の抵抗スポット溶接装置。 The resistance spot welding device according to claim 1 or 2, wherein the electrode is inserted through the through holes of the pair of first shaft parts and the through holes of the second shaft part, and a double pipe is provided within the electrode through which cooling water can flow back and forth.
  5. 　前記電極は、前記一対の第１軸部の貫通孔と前記第２軸部の貫通孔内を挿通し、前記電極内に冷却水を往復通水可能な２重管が設けられる、請求項３に記載の抵抗スポット溶接装置。 The resistance spot welding device according to claim 3, wherein the electrode is inserted through the through holes of the pair of first shaft parts and the through hole of the second shaft part, and a double pipe is provided within the electrode through which cooling water can flow back and forth.
  6. 　請求項１又は２に記載の抵抗スポット溶接装置を用いて、
    　亜鉛系めっきが施された鋼板及びＣ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上の鋼板を含む複数の鋼板、又は、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板を少なくとも１枚有する複数の鋼板、をスポット溶接する抵抗スポット溶接方法。     Using the resistance spot welding device according to claim 1 or 2,
    Disclosed is a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
  7. 　請求項３に記載の抵抗スポット溶接装置を用いて、
    　亜鉛系めっきが施された鋼板及びＣ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上の鋼板を含む複数の鋼板、又は、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板を少なくとも１枚有する複数の鋼板、をスポット溶接する抵抗スポット溶接方法。     Using the resistance spot welding device according to claim 3,
    Disclosed is a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
  8. 　請求項４に記載の抵抗スポット溶接装置を用いて、
    　亜鉛系めっきが施された鋼板及びＣ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上の鋼板を含む複数の鋼板、又は、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板を少なくとも１枚有する複数の鋼板、をスポット溶接する抵抗スポット溶接方法。     Using the resistance spot welding device according to claim 4,
    Disclosed is a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
  9. 　請求項５に記載の抵抗スポット溶接装置を用いて、
    　亜鉛系めっきが施された鋼板及びＣ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上の鋼板を含む複数の鋼板、又は、Ｃ：０．０８質量％以上、Ｓｉ：０．５０質量％以上を含み、引張強度が９８０ＭＰａ以上で、かつ亜鉛系めっきが施された鋼板を少なくとも１枚有する複数の鋼板、をスポット溶接する抵抗スポット溶接方法。     Using the resistance spot welding device according to claim 5,
    Disclosed is a resistance spot welding method for spot welding a plurality of steel sheets including a zinc-based plated steel sheet and a steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si and having a tensile strength of 980 MPa or more, or a plurality of steel sheets including at least one zinc-based plated steel sheet containing 0.08 mass% or more of C and 0.50 mass% or more of Si, having a tensile strength of 980 MPa or more.
PCT/JP2024/004345 2023-02-15 2024-02-08 Resistance spot welding device, and resistance spot welding method WO2024171943A1 (en)

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JP2004082168A (en) * 2002-08-27 2004-03-18 Honda Motor Co Ltd Positioning tool for electrode of spot welder
JP2013071170A (en) * 2011-09-29 2013-04-22 Fuji Heavy Ind Ltd Spot welding equipment
JP2020530401A (en) * 2017-08-14 2020-10-22 ノベリス・インコーポレイテッドＮｏｖｅｌｉｓ Ｉｎｃ． Resistance spot welding reinforced by electromagnets
US20220203473A1 (en) * 2020-12-24 2022-06-30 Hyundai Motor Company Electrode for resistance spot welding and device for resistance spot welding including the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004082168A (en) * 2002-08-27 2004-03-18 Honda Motor Co Ltd Positioning tool for electrode of spot welder
JP2013071170A (en) * 2011-09-29 2013-04-22 Fuji Heavy Ind Ltd Spot welding equipment
JP2020530401A (en) * 2017-08-14 2020-10-22 ノベリス・インコーポレイテッドＮｏｖｅｌｉｓ Ｉｎｃ． Resistance spot welding reinforced by electromagnets
US20220203473A1 (en) * 2020-12-24 2022-06-30 Hyundai Motor Company Electrode for resistance spot welding and device for resistance spot welding including the same

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