Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Toru Hioki

Shuhei Ogura

Takashi Goto

Atsushi Kawakita

Kohei Hisada

Kazuyuki Ogusu

Ryosuke Kawai

Shun Kato

Hideaki Matsuoka

Manabu Ooga

Shuichi Matsumoto

Tatsuyuki Amago

Takashi Asada

Koki Nakada

Hiroki Toriyama

Masahiro Nakata

Naoya Kato

Koji Nomura

Junichiro Makino

Masaki Morino

Yoichi Tsutsumi

Tomonori Yanagawa

Kenji Fukushima

Kazuho Takishita

An electrode tip for resistance spot welding includes a main body with tip and base portions. The tip portion has a bottomed and substantially cylindrical shape. The base portion has a substantially cylindrical shape and merges into the tip portion. The main body is made of a copper alloy such as chromium copper. The tip portion has a bottom part and a barrel part. The bottom part has a pressure-contact surface that is not recessed with respect to a workpiece to be pressed. The barrel part has a substantially cylindrical shape and merges into the bottom part. The electrode tip may have an inner diameter ratio (inner diameter of the barrel part to an outer diameter of the base portion) of 0.4 to 0.6, and may also have a bottom thickness ratio (thickness of the bottom part to the outer diameter of the base portion) of 0.15 to 0.5.

Electrode tip for resistance spot welding

While a laser-beam application position is moved along a locus which circularly or elliptically circles around a locus center so as to cross a weld line that is a boundary between a first metal plate and a second metal plate overlapped with each other, the locus center is moved in a direction parallel to a weld line. A moving direction of the laser-beam application position is set such that the laser beam is first applied to the first metal plate and then to the second metal plate when the laser beam passes through an unmelted zone of the first metal plate and the second metal plate. The unmelted zone is located downstream of a range through which the laser beam has already passed in the direction parallel to the weld line.

Laser-beam welding method and laser-beam welding apparatus

A laser welding method is provided to ensure a sufficient joining strength between metal plates by increasing the area of a joining region while preventing 'burn through' of a molten metal. In the laser welding method by applying a laser beam to a surface of multiple metal plates superimposed on each other, a scanning locus with the laser beam is sequentially shifted from an inner circular scanning locus to an outer one in a predetermined joining region on the metal plates, and an emission interval is provided to temporally stop the metal-plate-surface irradiation when the scanning locus is shifted. Thus, every time the scanning locus is shifted, the molten metal due to the previous irradiation is cooled and increases its viscosity. Accordingly, the 'burn through' is prevented regardless of increase of the area of the joining region, which results in a sufficient joining strength between the metal plates.

Laser welding method

In a laser welding method, generation of relatively large blow holes in a welding part is prevented while decrease in productivity is reduced. The laser welding method for lap welding, using a laser beam LB, of a plurality of metal plates and including an aluminum alloy cast plate includes: a melting path of scanning and irradiating circularly a superimposed part of the aluminum alloy plate and the aluminum alloy cast plate with a first laser beam LBto form a molten pool of the molten aluminum alloy plate and the molten aluminum alloy cast plate; and a stirring path of scanning and irradiating circularly the molten pool with a second laser beam LBhaving a scanning speed Vfaster than a scanning speed Vof the first laser beam LBto stir the molten pool.

An electrode tip portion is provided with a projection portion and a plurality of recess portions. The plurality of the recess portions are independent of one another, and are provided at the electrode tip portion in a dispersed manner. The projection portion is a region other than regions where the recess portions are provided, and is configured to be equipped with a continuous surface that continues in regions among the plurality of the recess portions.

Electrode for resistance spot welding

Provided are a method and an apparatus for resistance spot welding in which preliminary current application is executed and then main welding is executed in accordance with master patterns of various parameters obtained during the preliminary current application. The main welding is executed under welding conditions of the master patterns, and whether a welding abnormality has occurred and whether the welding abnormality is likely to occur are determined. When the welding abnormality is likely to occur, the welding conditions for the main welding are corrected so as to prevent the welding abnormality. When the welding abnormality is unlikely to occur, the welding conditions for the main welding are corrected so as to match the master patterns.

Resistance spot welding method and resistance spot welding apparatus

A highly corrosion-resistant spot weldment can be produced at low cost without occurrence of prominent protrusions and the like on the surface. The spot weldment is joined by a nugget formed inside stacked sheet materials through bringing a pair of electrodes arranged opposite to each other into pressure contact with the stacked sheet materials from outside and energizing the stacked sheet materials from the electrodes. The nugget has a diameter that is &#x2265;4&#x221a;t (t: thickness of sheet material) and a flattening level of 3.5 to 8, which is a ratio of diameter to thickness. Both outer surface parts of the sheet materials are free from protrusions formed due to bulging of molten metal. Even when the electrodes are made of a copper alloy, the increased amount of Cu in the outer surface parts is 0.2 mass % or less with respect to the component composition before spot welding.

Spot weldment

Partial welding of partially joining together two metal plates by melting at least one area inside a joining region of the metal plates is performed. After a lapse of a predetermined time from completion of the partial welding, main welding of joining together the metal plates by melting the joining region entirely is performed.

Welding method

A resistance spot welding method includes sandwiching metal plates put on top of one another between a pair of electrodes and performing resistance spot welding sequentially on a plurality of welding points close to each other on the metal plates by performing a current application between the electrodes so as to join the metal plates to each other. A welding current value to form a welding nugget at a welding point to be subjected to the resistance spot welding second or later among the welding points is set to be higher than a first welding current value to form a first welding nugget at a first welding point to be subjected to the resistance spot welding first among the welding points.

Resistance spot welding method

Objects to be welded are joined together by laser welding to form adjacent nuggets. When a distance between central axes of the adjacent nuggets is p and a diameter of the adjacent nuggets in the objects to be welded is d, the adjacent nuggets are formed so as to satisfy an equation 1.0&#x3c;p/d&#x2264;1.6.

Welding method and welded structure

A laser welding method for welding a plurality of objects to be welded by applying a laser beam scanned by a scanning unit to the plurality of objects to be welded while moving the scanning unit in a welding direction along a welding path, the laser welding method including the steps of: performing a step of preliminary-fixation-welding on a predetermined place in the welding direction of the objects to be welded, and a step of main-welding on a place corresponding to the preliminarily-fixed place of the object to be welded within a scanning range of the scanning unit while moving the scanning unit. Further, when the place corresponding to the preliminarily-fixed place of the object to be welded is main-welded, the place is main-welded in a state where both sides of the place to be main-welded are restrained.

A welding method according to the invention is a welding method in which welding is performed by emitting a high-energy beam onto a welding object that includes a plurality of overlapped metal sheets. This welding method includes forming a tack weld nugget at a welding point on the welding object, and forming a plurality of final weld nuggets along a virtual closed curve that encircles the tack weld nugget, while leaving the tack weld nugget, at the welding point.

A welding method according to the present invention is a welding method for irradiating an object to be welded including a plurality of metallic plates that are stacked on each other with a high energy beam and performing welding. The welding method includes: forming a plurality of tack weld nuggets along a virtual closed curve on a part to be welded of the object to be welded; and forming a plurality of main weld nuggets so that the main weld nuggets overlap the plurality of respective tack weld nuggets.

A laser welding method includes: projecting a laser beam onto irradiation regions on plural metallic workpieces such that a weld section is formed when the workpieces are joined by laser welding, the weld section being formed of plural nuggets, and each of the irradiation regions being formed with each of the nuggets. The nuggets are sequentially formed by sequentially projecting the laser beam onto the irradiation regions that respectively correspond to the nuggets. The laser beam is projected onto each of the irradiation regions such that an amount of input heat from the laser beam that is projected onto each of the irradiation regions to the workpiece is reduced as the nuggets are sequentially formed.

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Miyoshi, Japan

Toru Hioki