JP2013071173A - Spot welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide spot welding equipment that can decrease the number of positioning jigs which position a workpiece to be welded.SOLUTION: Spot welding equipment 10 is to mutually joint plate materials together not only by holding and pressurizing a workpiece 18 formed by joining a plurality of plate materials on top of one another, from both sides of a pair of welding electrodes 12 and 17 but also by forming nuggets by flowing electric current to the pair of welding electrodes 12 and 17. A holding mechanism 21 is provided to hold the workpiece 18 from both sides to position the workpiece 18 before the workpiece 18 is held by the pair of the welding electrodes 12 and 17, thereby preventing the plate materials from deforming by the pressurization forces of the pair of the welding electrodes 12 and 17.

Description

  The present invention relates to a spot welding apparatus having a pair of welding electrodes for gripping a workpiece to be welded from both sides, and a gripping mechanism for gripping the workpiece from both sides together with a pair of welding electrodes.

  A spot welding apparatus is used to weld a workpiece in which plate materials such as a plurality of steel plates are overlapped. In the spot welding apparatus, a plurality of plate members are overlapped to form a joining target part, and the joining target part is gripped from both sides with a pair of welding electrodes and pressed. A current is passed between the pair of welding electrodes, a nugget is formed by Joule heat, and a plurality of plate materials are joined to each other.

  An example of such a spot welding apparatus is described in Patent Document 1. In the spot welding apparatus described in Patent Document 1, an arm is provided for each of a pair of welding robots, and a spot welding gun is attached to each arm via a wrist portion. Each list part is provided with a positioning gauge individually. Each positioning gauge is formed by integrally forming a ring-shaped pressing plate (pressing member) at the tip of a stay connected to each wrist part. Furthermore, the spot welding apparatus described in Patent Document 1 has a positioning jig for positioning a workpiece to be welded.

  In the spot welding apparatus described in Patent Document 1, a work is first positioned and clamped by a positioning jig. Next, the upper and lower spot welding guns are moved to the welding position and face each other. Furthermore, the workpiece is pressed and clamped by the electrode of the spot welding gun. And spot welding is performed by energizing following the pressurization operation of the work by both welding electrodes. At this time, until each welding electrode comes into contact with the workpiece and reaches the set pressure, both positioning gauges face each other and pressurize and hold the peripheral portion of the workpiece corresponding to the welding electrode.

  On the other hand, after welding, it is set so that the applied pressure of the positioning gauge is released while the applied pressure of the welding electrode is released. In the spot welding apparatus described in Patent Document 1, it is said that by performing such a process, the workpiece can be prevented from being deformed by the pressure of the welding electrode of the spot welding gun.

Japanese Patent Laid-Open No. 6-1555039

  However, in the spot welding apparatus described in Patent Document 1, a positioning jig for positioning the workpiece has to be provided, and there is a problem that the number of positioning jigs increases.

  An object of the present invention is to provide a spot welding apparatus capable of reducing the number of positioning jigs for positioning a workpiece.

  The spot welding apparatus of the present invention is configured to grip and press a workpiece on which a plurality of plate materials are stacked from both sides with a pair of welding electrodes, and to form a nugget by passing an electric current through the pair of welding electrodes. A spot welding apparatus for joining together, wherein the workpiece is positioned from both sides before being gripped by the pair of welding electrodes, and the workpiece is positioned by the applied pressure of the pair of welding electrodes. A gripping mechanism that prevents the plate material from being deformed is provided.

  In the spot welding apparatus of the present invention, the plurality of plate materials include plate materials having different thicknesses, and the thickness of the plate material positioned on one end side in the stacking direction is equal to that of the plate material positioned on the other end side in the stacking direction. A plurality of plate materials are stacked so as to be thinner than the thickness, and the gripping mechanism includes a first grip portion that pressurizes the plate material positioned on the one end side, and a second that pressurizes the plate material positioned on the other end side. And a grip portion.

  The spot welding apparatus of the present invention is characterized in that an actuator for operating the gripping mechanism is provided so as to grip the workpiece from both sides.

  The spot welding apparatus according to the present invention includes a moving mechanism that moves the gripping mechanism along a direction in which the pair of welding electrodes pressurize the workpiece, and an operating force in the moving direction of the gripping mechanism. An operating force conversion mechanism that converts the gripping force into a gripping force when gripping the workpiece is provided.

  According to the spot welding apparatus of the present invention, the gripping mechanism prevents the workpiece plate material from being deformed by the function of gripping the workpiece before being gripped by the pair of welding electrodes from both sides and the pressure of the pair of welding electrodes. It has the function to do. Therefore, the number of positioning jigs for positioning the workpiece can be reduced.

  According to the spot welding apparatus of the present invention, the workpiece is positioned by the gripping mechanism by the first gripping portion pressing the relatively thin plate material and the relatively thick plate material by the second gripping portion.

  According to the spot welding apparatus of the present invention, the gripping mechanism is operated by the actuator so that the workpiece can be gripped from both sides.

  According to the spot welding apparatus of the present invention, the moving force of the gripping mechanism is converted into the gripping force when gripping the workpiece by the gripping mechanism. Therefore, it is not necessary to provide a dedicated actuator for generating a gripping force by the gripping mechanism.

It is a typical side view which shows 1st Embodiment of the spot welding apparatus in this invention. It is sectional drawing of the state which hold | gripped the workpiece | work with a pair of electrode in the spot welding apparatus of this invention, and was hold | gripped with the 1st and 2nd pressurization plate. It is a typical side view which shows 2nd Embodiment of the spot welding apparatus in this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a first embodiment of a spot welding apparatus. A spot welding apparatus 10 has a welding gun body 11 formed by a C-shaped yoke member. The welding gun body 11 is attached to an arm of a welding robot (not shown), and the welding gun body 11 can be moved in either the horizontal direction or the vertical direction by the operation of the arm of the welding robot. Yes. A lower end portion of the welding gun main body 11 in FIG. 1 is formed with a protruding portion 11a extending in the horizontal direction, and a cylindrical welding electrode (electrode tip) 12 is formed at the tip of the protruding portion 11a. It is attached. In the present embodiment, description will be made assuming that the welding electrode 12 is attached to the welding gun main body 11 so as not to move in the vertical direction and the horizontal direction. When the welding gun body 11 is moved up and down, the welding electrode 12 can be moved up and down. The welding electrode 12 is provided around a vertical axis A, and the tip of the welding electrode 12 is directed upward. The tip of the welding electrode 12 is formed in a hemispherical shape.

  On the other hand, an electrode driving actuator 13 for operating the welding electrode 17 is attached to the upper end of the welding gun body 11. An electrode driving rod 14 that is reciprocated in the direction along the axis B (that is, the vertical direction) is provided by the power of the electrode driving actuator 13. The axis A and the axis B are parallel to each other and are not arranged coaxially. A rod 16 is attached to the tip of the electrode drive rod 14, specifically, the lower end with a connecting portion 15 interposed. And the welding electrode (electrode tip) 17 is attached to the front-end | tip of the rod 16, specifically, a lower end. For this reason, when the electrode drive rod 14 moves in the vertical direction while the welding gun main body 11 is stopped, the welding electrode 17 can move in the vertical direction along the axis A. The welding electrode 17 is configured in a cylindrical shape, and the welding electrode 17 is disposed around the axis A. The tip of the welding electrode 17 is directed downward, and the tip of the welding electrode 17 is formed in a hemispherical shape. In this way, when the welding electrode 17 moves in the vertical direction along the axis A by the power of the electrode driving actuator 13, the distance between the welding electrode 12 and the welding electrode 17 changes.

  As shown in FIG. 2, the spot welding apparatus 10 according to the present embodiment grips and clamps the workpiece 18 from the thickness direction, specifically, the vertical direction by a pair of welding electrodes 12 and 17. Is. That is, the pair of welding electrodes 12 and 17 constitutes a main pressing member in the spot welding apparatus 10. In addition, the workpiece 18 includes a plurality of plate members, for example, three plate members 18a, 18b, and 18c, which are overlapped in the thickness direction to form a welding target portion 18d. The three plate members 18a, 18b, 18c are stacked one above the other. The welding target portion 18d is welded by the spot welding apparatus 10. Further, the plate members 18a, 18b, 18c have different thicknesses. Specifically, the thickness of the plate material 18a is thinner than the single thickness of the plate materials 18b and 18c, and the thickness of the plate materials 18b and 18c is the same.

  On the other hand, a gripping mechanism actuator 19 (hereinafter abbreviated as actuator 19) is attached to the side of the electrode driving actuator 13 in the welding gun body 11. The actuator 19 is provided with a gripping mechanism 21 with a drive rod 20 interposed. The gripping mechanism 21 is a device for positioning the workpiece 18. Here, “positioning the workpiece 18” includes holding the workpiece 18 in the vicinity of a predetermined welding position in the conveyance path of the workpiece 18, positioning the plate members 18a, 18b, 18c with each other, and the like. It is. The drive rod 20 is configured to reciprocate in the direction along the axis C, that is, in the vertical direction. Thus, when the drive rod 20 is operated by the actuator 19, the gripping mechanism 21 is configured to move in the vertical direction.

  The gripping mechanism 21 includes a boss portion 22 fixed to the lower end of the drive rod 20, a first pressure plate (individual pressure plate) 23 extending from the boss portion 22 toward the axis A, and a boss portion 22. It has the 2nd pressurization plate (individual pressurization plate) 24 attached with respect to rocking | fluctuation. Further, an actuator 25 that generates a force for swinging the second pressure plate 24 is provided. The first pressure plate 23 is formed integrally with the boss portion 22, and the front end of the first pressure plate 23 is bifurcated as shown in FIG. 23b is formed.

  Further, when the first pressure plate 23 is moved in the vertical direction by the power of the actuator 19, the welding electrodes 12 and 17 and the first pressure plate 23 are positioned at the same height. , 17 and the first pressure plate 23 are not in contact with each other. Specifically, when the first pressure plate 23 is raised or lowered, the axis A is positioned between the two pressure units 23a and 23b in a plane perpendicular to the axis A. Yes.

  A second pressure plate 24 is provided below the first pressure plate 23 configured as described above. The second pressure plate 24 is attached to the boss portion 22 so as to be swingable about the support shaft 26. The support shaft 26 is provided in the horizontal direction between the actuator 25 and the first pressure plate 23. More specifically, the second pressure plate 24 can swing around the support shaft 26 in a vertical plane including the two axes A and C. As shown in FIG. 2, the tip of the second pressure plate 24 is bifurcated to form two pressure portions 24a and 24b. In addition, in the plane cross section along the conveyance direction of the workpiece | work 18 and a perpendicular direction, the cross-sectional shape of the pressurization part 23a, 23b, 24a, 24b is a square, and the surface which contacts the workpiece | work 18 is flat. It has become.

  The actuator 25 is fixed to the boss portion 22, and the actuator 25 has a plunger 25a that reciprocates in the horizontal direction. As this actuator 25, for example, a pneumatic cylinder or a hydraulic cylinder can be used. One end of two links 27a and 27b is rotatably connected to the tip of the plunger 25a via a support shaft 25b. The other end of the link 27a is rotatably connected to the rear end of the second pressure plate 24 via a support shaft 28, and the other end of the link 27b is attached to the boss portion 22 via a support shaft 29 so as to be swingable. ing. Therefore, when the plunger 25a of the actuator 25 reciprocates, the operating force of the plunger 25a is transmitted to the second pressure plate 24, and the second pressure plate 24 swings about the support shaft 26.

  For example, when the plunger 25a moves toward the second pressure plate 24, that is, in the left direction in FIG. 1, the second pressure plate 24 rotates around the support shaft 26 in the clockwise direction within a predetermined angle range. By the operation of the second pressure plate 24, the distance between the first pressure plate 23 and the second pressure plate 24 is narrowed. On the other hand, when the plunger 25a moves away from the second pressure plate 24, that is, in the right direction in FIG. 1, the second pressure plate 24 is counterclockwise around the support shaft 26 within a predetermined angle range. Rotate with. By the operation of the second pressure plate 24, the distance between the first pressure plate 23 and the second pressure plate 24 is widened.

  Further, when the second pressure plate 24 is moved up and down by the power of the actuator 19 or when the second pressure plate 24 is swung by the power of the actuator 25, Even when the two pressure plates 24 are positioned at the same height, the welding electrodes 12 and 17 and the second pressure plate 24 are configured not to contact each other.

  In the spot welding apparatus 10 of the present embodiment, the workpiece 18 is gripped by the first pressure plate 23 and the second pressure plate 24 before the welding target portion 18d of the workpiece 18 is gripped by the pair of welding electrodes 12 and 17. can do. That is, in the spot welding apparatus 10, the first pressure plate 23 and the second pressure plate 24 constitute a sub-pressure member. In addition, 30 shown by FIG. 1 is a transformer (transformer) which comprises a part of electric power system of a welding robot.

  Below, the process of welding the workpiece | work 18 with the spot welding apparatus 10 of 1st Embodiment is demonstrated.

(First step)
First, a state in which the distance between the pair of welding electrodes 12 and 17 is maintained at a value exceeding the thickness of the welding target portion of the workpiece 18 and the first pressure plate 23 and the second pressure plate 24 are open. 2, the work 18 is conveyed in the horizontal direction, between the pair of welding electrodes 12, 17, and between the first pressure plate 23 and the second pressure plate 24. To enter.

(Second step)
The first pressure plate 23 is lowered by the power of the actuator 19, the first pressure plate 23 is pressed against the plate material 18 a, and the first pressure plate 23 is stopped.

(Third step)
The plunger 25a is moved leftward in FIG. 1 by the power of the actuator 25, and the second pressure plate 24 is rotated clockwise about the support shaft 26. By the operation of the second pressure plate 24, the welding target portion of the workpiece 18 is gripped from above and below by the first pressure plate 23 and the second pressure plate 24 as shown in FIG. Here, the second pressure plate 24 is pressed against the plate material 18c. As described above, the first pressure plate 23 and the second pressure plate 24 grip the workpiece 18 to be welded from both sides to position the work 18.

(4th process)
The first pressure plate 23 and the second pressure plate 24 are lowered by the actuator 19 while the work 18 is gripped from both sides in the vertical direction by the first pressure plate 23 and the second pressure plate 24. Further, the welding electrode 17 is lowered by the power of the electrode driving actuator 13, the welding target portion of the work 18 is sandwiched and pressed by the pair of welding electrodes 12, 17, and the welding electrode 17 is stopped. At the same time, the first pressure plate 23 and the second pressure plate 24 are stopped. Further, a current is passed between the pair of welding electrodes 12 and 17 to form a nugget by Joule heat to join the plurality of plate members 18a, 18b and 18c to each other. In this way, the fourth step is completed.

  In the fourth step, the thickness of the uppermost plate member 18a is thinner than the individual thicknesses of the plate members 18b and 18c and has a lower rigidity. A gap is about to occur between 18a and the plate 18b. On the other hand, in this embodiment, both sides of the location where the welding electrode 17 presses the plate material 18a are pressed by the two pressing portions 23a and 23b of the first pressing plate 23. For this reason, it can prevent that the thin board | plate material 18a deform | transforms with the applied pressure of the welding electrode 17. FIG. Therefore, a decrease in current density between the thin plate material 18a and the thick plate material 18b is suppressed, a decrease in welding quality can be prevented, and generation of spatter can be avoided.

  Further, after the workpiece 18 is gripped and pressed by the gripping mechanism 21, the workpiece 18 is gripped and pressed by the welding electrodes 12 and 17. For this reason, even if the workpiece 18 has a relatively large plate thickness ratio, a plate having a relatively low rigidity, or a variation in the physical properties of the plate, the welding quality can be stabilized. it can. The plate pressure ratio is a value obtained by dividing the thickness of the thick plate by the thickness of the thin plate.

  In the present embodiment, both sides of the position where the welding electrode 17 presses the plate material 18a are pressed by the pressurizing portions 23a and 23b of the first pressure plate 23, so that the plate material 18a is pressed by the welding electrode 17. Prevents deformation. For this reason, the applied pressure applied from the welding electrode 17 to the plate material 18a can be made lower than the applied pressure applied from the welding electrode 12 to the plate material 18c.

  When the process of spot welding the workpiece 18 is completed in the fourth step, the distance between the pair of welding electrodes 12 and 17 is increased. Further, the second pressure plate 24 is rotated counterclockwise about the support shaft 26, and the gripping on the workpiece 18 is released. And the workpiece | work 18 by which spot welding was performed is conveyed by the following process.

  As described above, according to the spot welding apparatus 10 of the present embodiment, the gripping mechanism 21 grips the workpiece 18 before being gripped by the pair of welding electrodes 12 and 17 from both sides, and the pair of welding electrodes 17. It also has the function of preventing the plate material of the workpiece 18 from being deformed by the applied pressure. Therefore, it is not necessary to provide a dedicated positioning jig for positioning the workpiece 18 to be welded, and the number of positioning jigs can be reduced. Further, after the workpiece 18 is gripped and pressed by the first pressure plate 23 and the second pressure plate 24, the workpiece 18 is gripped and pressed by the welding electrodes 12 and 17. Therefore, even if any of the welding electrodes 12 and 17 comes into contact with the workpiece 18 first, deformation of the plate material constituting the workpiece 18 can be suppressed.

  The spot welding apparatus 10 of the present embodiment can also spot weld a workpiece in which a thin plate material is arranged at the bottom and two thick plate materials are arranged on a thin plate material. In this case, the welding electrode 12 is pressed against the thin plate material, the welding electrode 17 is pressed against the thick plate material, and the workpiece is gripped from both sides. For this reason, it can prevent that a thin board | plate material deform | transforms with the pressurizing force of the welding electrode 12, and can acquire the effect similar to the above-mentioned.

  Next, the structure of the spot welding apparatus 10 in 2nd Embodiment is demonstrated with reference to FIG. In the configuration of FIG. 3, the same components as those of FIGS. 1 and 2 are denoted by the same reference numerals as those of FIGS. When the second embodiment is compared with the first embodiment, the mechanism for operating the second pressure plate 24 is different. In the second embodiment, the second pressure plate 24 is configured to be operated by the cam mechanism 31. In the second embodiment, the frame 32 is attached to the arm of the welding robot, and the cam mechanism 31 is attached to the frame 32. The cam mechanism 31 includes a cam plate 33 fixed to the frame 32, a groove 34 provided in the cam plate 33, and a rolling element 35 that can roll in the groove 34.

  The groove 34 extends in the vertical direction, and cam surfaces 34 a are provided on both sides of the uppermost portion of the groove 34. The cam surface 34a is linear along the vertical direction. In addition, cam surfaces 34b that are inclined with respect to the cam surface 34a are provided on both sides of the groove 34 in an intermediate portion in the vertical direction. The cam surface 34b is inclined in a direction closer to the boss portion 22 as it is lower. Further, cam surfaces 34 c are provided on both sides of the groove 34 that is the lowest part in the vertical direction. The cam surface 34c is formed in a straight line along the vertical direction. The intervals between the cam surfaces formed on both sides of the groove 34 are set to be the same, the connecting portion between the cam surface 34a and the cam surface 34b is curved, and the connecting portion between the cam surface 34b and the cam surface 34c is curved. Has been. Furthermore, the rolling element 35 has a spherical shape or a cylindrical shape.

  When the rolling element 35 rolls up and down along the groove 34, the rolling element 35 is guided by the cam surfaces 34a, 34b, and 34c and moves in the horizontal direction. Specifically, it moves in the horizontal direction within a vertical plane including the axes A and C. For example, when the rolling element 35 rolls along the cam surface 34a, the rolling element 35 does not move in the horizontal direction.

  Further, when the rolling element 35 is rolling from top to bottom along the cam surface 34b, the rolling element 35 moves in the horizontal direction. Specifically, the rolling element 35 moves in a direction approaching the boss portion 22. On the other hand, when the rolling element 35 is rolling from bottom to top along the cam surface 34b, the rolling element 35 moves in the horizontal direction. Specifically, the rolling element 35 moves in a direction away from the boss portion 22. Furthermore, when the rolling element 35 is rolling along the cam surface 34c, the rolling element 35 does not move in the horizontal direction.

  On the other hand, the rolling element 35 is rotatably attached to one end side of the shaft 36. Further, a cylindrical slide bearing 37 is attached to the boss portion 22, and the shaft 36 is supported by the slide bearing 37 so as to be movable in the horizontal direction. Specifically, the shaft 36 can reciprocate in a vertical plane including the axes A and C. Further, when the boss portion 22 is moved in the vertical direction by the actuator 19, the shaft 36 moves in the vertical direction integrally with the boss portion 22. The links 27a and 27b are coupled to the end of the shaft 36 opposite to the end to which the rolling elements 35 are attached so as to be rotatable about the support shaft 36a. For this reason, when the rolling element 35 moves in the horizontal direction, the moving force of the rolling element 35 is transmitted to the shaft 36, and the shaft 36 moves in the horizontal direction.

  For example, when the shaft 36 moves in a direction approaching the second pressure plate 24, the operating force of the shaft 36 is transmitted to the second pressure plate 24. As a result, the second pressure plate 24 rotates clockwise by a predetermined angle about the support shaft 26, and the interval between the first pressure plate 23 and the second pressure plate 24 is narrowed. On the other hand, when the shaft 36 moves in a direction away from the second pressure plate 24, the operating force of the shaft 36 is transmitted to the second pressure plate 24. As a result, the second pressure plate 24 rotates counterclockwise by a predetermined angle about the support shaft 26, and the interval between the first pressure plate 23 and the second pressure plate 24 is widened.

  As described above, in the spot welding apparatus 10 according to the second embodiment, the operating force in the vertical direction of the boss portion 22 is converted into the operating force for opening and closing the first pressure plate 23 and the second pressure plate 24. It is configured as follows. Specifically, an operating force conversion mechanism 38 that converts an operating force in the horizontal direction of the rolling element 35 that rolls along the groove 34 into an operating force that operates the second pressure plate 24 is provided. That is, the operating force conversion mechanism 38 is configured by elements such as the groove 34 having the cam surface, the rolling element 35, the shaft 36, and the sliding bearing 37.

  Next, the process of welding the workpiece | work 18 with the spot welding apparatus 10 of 2nd Embodiment is demonstrated.

(First step)
In the spot welding apparatus 10 of the second embodiment, the operation performed in the first process is the same as the operation of the first process of the spot welding apparatus 10 of the first embodiment.

(Second step)
The first pressure plate 23 and the shaft 36 are lowered by the power of the actuator 19. While the shaft 36 is descending, the shaft 36 does not move in the horizontal direction while the rolling element 35 rolls along the cam surface 34a. For this reason, the space | interval between the 1st pressurization plate 23 and the 2nd pressurization plate 2 does not change. That is, at this time, the work 18 is not gripped by the first pressure plate 23 and the second pressure plate 24.

(Third step)
When the lowering of the shaft 36 is continued and the rolling element 35 rolls along the cam surface 34 b, the shaft 36 moves horizontally in a direction approaching the second pressure plate 24. As a result, the second pressure plate 24 rotates clockwise around the support shaft 26, and the work 18 is gripped from both sides in the vertical direction by the first pressure plate 23 and the second pressure plate 24. That is, the first pressure plate 23 and the second pressure plate 24 grip the welding target portion 18d from both sides, and the workpiece 18 is positioned at the welding position.

(4th process)
The welding electrode 17 is lowered by the power of the electrode driving actuator 13, the welding target portion 18 d of the work 18 is sandwiched and pressurized by the pair of welding electrodes 12, 17, and the welding electrode 17 is stopped. While the welding electrode 17 is descending, the shaft 36 continues to descend with the power of the actuator 19, but the rolling element 35 rolls along the cam surface 34c. Therefore, the shaft 36 does not move in the horizontal direction, and the state where the workpiece 18 is gripped by the first pressure plate 23 and the second pressure plate 24 is maintained. When the welding electrode 17 is stopped, the boss portion 22 is also stopped, the workpiece 18 is gripped and pressurized by the welding electrodes 12 and 17, and the workpiece 18 is gripped by the first pressure plate 23 and the second pressure plate 24. Maintained in a pressurized state. Then, a current is passed between the pair of welding electrodes 12 and 17 to spot weld the workpiece 18, and the fourth step is completed.

  When the process of spot welding the workpiece 18 in the fourth step is finished, the distance between the pair of welding electrodes 12 and 17 is widened, and the gripping of the workpiece 18 by the welding electrodes 12 and 17 is released. Further, when the boss portion 22 is raised by the actuator 19 and the rolling element 35 is raised while rolling along the cam surface 34 b, the shaft 36 moves horizontally in a direction away from the second pressure plate 24. As a result, the second pressure plate 24 is rotated counterclockwise about the support shaft 26, and the grip on the workpiece 18 is released. And the workpiece | work 18 by which spot welding was performed is conveyed by the following process.

  As described above, in the spot welding apparatus 10 according to the second embodiment, the same operational effects as those of the spot welding apparatus 10 according to the first embodiment can be obtained for the same components as those of the spot welding apparatus 10 according to the first embodiment. it can.

  Further, according to the spot welding apparatus 10 of the second embodiment, the vertical operating force of the gripping mechanism 21 is converted into a gripping force for gripping the workpiece 18 by the first pressure plate 23 and the second pressure plate 24. The Therefore, it is not necessary to provide a dedicated actuator for generating a gripping force by the gripping mechanism 21.

  Here, the correspondence between the configuration described in the present embodiment and the configuration of the present invention will be described. The plate 18a positioned at the top in the stacking direction is the “plate positioned at one end side in the stacking direction” in the present invention. The plate member 18c positioned at the bottom in the stacking direction corresponds to the “plate member positioned at the other end in the stacking direction” of the present invention, and the first pressure plate 23 is the first plate of the present invention. The second pressure plate 24 corresponds to the gripping portion, the second gripping portion of the present invention, the actuator 25 corresponds to the actuator of the present invention, and the actuator 19 corresponds to the moving mechanism of the present invention.

  The present invention is not limited to the first embodiment and the second embodiment, and various modifications can be made without departing from the scope of the invention. For example, you may use the pressurization member by which cross-sectional shape was comprised circularly as a 1st holding part and a 2nd holding part. Furthermore, the pair of welding electrodes in the present invention is an element that grips and pressurizes the workpiece by relative movement along a predetermined direction. For this reason, a pair of welding electrodes may be configured to move together with respect to the welding gun body.

  Furthermore, the pair of welding electrodes may be relatively moved in the horizontal direction, and the first gripping portion and the second gripping portion may be relatively moved in the horizontal direction. In this case, the overlapping direction of the plate members is the horizontal direction, and the conveying direction of the workpiece may be either the vertical direction or the horizontal direction.

  Furthermore, the plate material of the workpiece to be spot welded may be two pieces or four or more pieces. Further, the thicknesses of the plurality of plate materials may all be the same or different. Furthermore, the part which contacts the workpiece | work in a 1st holding part and a 2nd holding part can also be comprised with flexible materials, such as resin and rubber | gum which have heat resistance. If comprised in this way, even when the thickness of the workpiece | work which is welding object differs, a flexible material will absorb the difference in thickness by elastically deforming, and it can hold | grip reliably by a holding mechanism.

  Further, in the first to fourth steps described in the above embodiment, the workpiece having a plurality of plate members stacked thereon is gripped and pressed from both sides with a pair of welding electrodes, and a current is passed through the pair of welding electrodes to produce a nugget. It is a spot welding method for joining plate materials to each other by forming a workpiece with a pair of welding electrodes by positioning the workpiece by gripping the workpiece from both sides before being gripped by the pair of welding electrodes. The spot welding method which prevents that a board | plate material deform | transforms with the applied pressure at the time of pressurizing is provided.

DESCRIPTION OF SYMBOLS 10 Spot welding apparatus 12, 17 Welding electrode 18 Workpiece | work 18a, 18b, 18c Plate material 19, 25 Actuator 21 Grasp mechanism 23 1st pressurization plate (1st grip part)
24 2nd pressure plate (2nd holding part)
38 Operating force conversion mechanism

Claims (4)

Spot welding that joins the plate materials together by forming a nugget by passing a current through the pair of welding electrodes while pressing and pressing a workpiece on which a plurality of plate materials are stacked from both sides with a pair of welding electrodes A device,
A gripping mechanism that grips the workpiece from both sides before being gripped by the pair of welding electrodes and positions the workpiece, and prevents the plate material from being deformed by the applied pressure of the pair of welding electrodes is provided. A spot welding apparatus. The spot welding apparatus according to claim 1, wherein
The plurality of plate materials include plate materials having different thicknesses, and the plurality of plate materials located on one end side in the stacking direction are thinner than the thickness of the plate material positioned on the other end side in the stacking direction. Are stacked,
The spot welding device, wherein the gripping mechanism includes a first gripping portion that presses the plate material positioned on the one end side, and a second gripping portion that pressurizes the plate material positioned on the other end side. . The spot welding apparatus according to claim 1 or 2,
The spot welding apparatus, wherein an actuator is provided to operate the gripping mechanism so as to grip the workpiece from both sides. The spot welding apparatus according to claim 1 or 2,
A moving mechanism for moving the gripping mechanism along a direction in which the pair of welding electrodes pressurize the workpiece;
A spot welding apparatus comprising: an operating force conversion mechanism that converts an operating force in a moving direction of the gripping mechanism into a gripping force when the gripping mechanism grips the workpiece.

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