JP7189762B2 - Spot welding gun and spot welding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a spot welding gun and a spot welding method for increasing the number of welding points, enhancing welding strength, reducing weight, and improving workability when spot welding objects to be welded such as automobile panels.

A structure shown in FIG. 5 is known as a spot welding gun 100 used in a conventional welding device. FIG. 5 is a front view illustrating a conventional spot welding gun 100. FIG.

As shown in FIG. 5, the spot welding gun 100 mainly includes a gun head 101, a main electrode rod 102 disposed at the tip of the gun head 101, and a gun arm portion 104 rotatably attached to an arm attachment base portion 103. , a sub-electrode rod 105 disposed at the tip of the gun arm portion 104 and facing the main electrode rod 102, and handgrip portions 106 and 107 to be gripped by an operator during work.

The main electrode rod 102 is linearly advanced and retracted by air pressure supplied from an air supply mechanism (not shown), and the work is sandwiched between the tips of the main electrode rod 102 and the sub-electrode rod 105 and pressurized. Spot welding can be performed at By rotating the gun arm portion 104 in either the horizontal or vertical direction around the arm mounting base portion 103 as a fulcrum, the welding operation can be performed even at a deep position or a position where there is an obstructing member. (See Patent Document 1, for example).

JP-A-2002-224845

In the spot welding gun 100, the main electrode rod 102 and the sub-electrode rod 105 clamp the workpiece at their distal ends, and pressurize the workpiece by the air pressure from the air supply mechanism on the main electrode rod 102 side. spot welding is performed by passing an electric current through the At this time, the main electrode rod 102 and the sub-electrode rod 105 face each other in a linear positional relationship, so that a so-called nugget is formed in the work at one welding point in one welding process.

In spot welding, in order to improve the welding strength, the workpiece is hit continuously in one direction. On the other hand, there is a problem that shunting occurs and spot welding cannot be performed. On the other hand, in order to solve the problem of not being able to weld due to the split current, it is necessary to widen the distance between consecutive welding points. Issues arise.

Further, the spot welding gun 100 has a gun head 101 and the like for supplying air to the arm mounting base portion 103, the gun arm portion 104, and the main electrode rod 102, which increases its weight. Therefore, the operator needs to operate the handgrip portions 106 and 107 with both hands, which poses a problem of deterioration of workability.

The present invention has been made in view of the above circumstances, and is intended to increase the number of welding points to increase welding strength, reduce weight and improve workability when spot welding an object to be welded such as an automobile panel. To provide a spot welding gun and a spot welding method for

The spot welding gun of the present invention is a spot welding gun comprising a first electrode section and a second electrode section arranged facing each other with a gap for inserting an object to be welded therein. and a fixing portion for fixing the first electrode portion and the second electrode portion while maintaining the gap, and by scooping the fixing portion in one direction, the first electrode portion is , pressurizes a first pressurized region on one main surface of the object to be welded, and presses the second electrode portion on the other main surface of the object to be welded opposite to the one main surface; 2 pressurized regions, and the first pressurized region and the second pressurized region are horizontally shifted with respect to the one main surface of the object to be welded. It is characterized by applying current to the object to be welded and performing two-point welding.

In addition, the spot welding gun of the present invention further includes an operation portion that is connected to the fixed portion and operates the first electrode portion and the second electrode portion, and the fixed portion is to rotate the first electrode portion and the second electrode portion with respect to the object to be welded through It is characterized by generating

Further, in the spot welding gun of the present invention, the operating portion is rotatably connected to the fixed portion in the horizontal direction so that the axis of the operating portion substantially coincides with the center of the gap. It is characterized by

Further, in the spot welding gun of the present invention, the axial center of the first electrode portion is eccentric with respect to the axial center of the second electrode portion in a state before the operation portion is gouged. do.

Further, in the spot welding method of the present invention, the object to be welded is inserted into the gap between the first electrode portion and the second electrode portion of the spot welding gun, and the first electrode portion and the second electrode portion A spot welding method for welding the object to be welded by applying a current while pressurizing the object to be welded, wherein the spot welding gun maintains the gap while maintaining the first and a fixing part for fixing the electrode part and the second electrode part, and after inserting the object to be welded into the gap between the first electrode part and the second electrode part, the fixing part in one direction to rotate the first electrode portion and the second electrode portion with respect to the object to be welded, and the first electrode portion rotates one main surface of the object to be welded. The object to be welded comprises a first pressure area to be pressurized and a second pressure area to which the second electrode presses the main surface of the object to be welded and the other main surface opposite to the main surface of the object to be welded. A current is applied to the object to be welded in a state of being horizontally displaced with respect to the main surface of the object, thereby forming a nugget with two separated welding points in one welding process.

Further, in the spot welding method of the present invention, the spot welding gun further includes an operating section that is connected to the fixed section and that operates the first electrode section and the second electrode section. After inserting the object to be welded into the gap between the electrode portion and the second electrode portion, the operation portion is gouged out, and the first electrode portion and the second electrode portion are separated through the fixing portion. The object to be welded is rotated to generate the first pressurized area and the second pressurized area on the object to be welded.

Further, in the spot welding method of the present invention, the axial center of the first electrode portion is eccentric with respect to the axial center of the second electrode portion in a state before the operation portion is gouged. do.

Further, in the spot welding method of the present invention, the object to be welded is formed by superimposing two plate materials, and the nugget at the two welding points is formed from the two plate materials below the first pressure area. It is characterized in that the contact region and its periphery are separated from the contact region and its periphery of the two plate members above the second pressure region.

Further, in the spot welding method of the present invention, the object to be welded is formed by superimposing three plate materials, and the two-point nugget is the first electrode portion below the first pressure area. a contact region between the plate member in contact with the plate member positioned in the middle and the periphery thereof, and the plate member in contact with the second electrode portion above the second pressure region and the plate member positioned in the middle It is characterized in that it is formed apart from the contact area with and the periphery thereof.

A spot welding gun according to the present invention comprises a first electrode section and a second electrode section which are arranged facing each other with a gap for inserting an object to be welded, wherein the first electrode section The first pressurized region by and the second pressurized region by the second electrode portion are shifted in the horizontal direction with respect to one main surface of the object to be welded. With this structure, welding strength can be improved by forming a nugget at two welding points in one spot welding process.

Further, the spot welding gun of the present invention includes a fixing portion for fixing the first and second electrode portions, and an operation portion rotatably connected to the fixing portion, and the first and second electrodes are separated by scooping out the operation portion. The second electrode portion can be rotated with respect to the object to be welded to generate a first pressure area and a second pressure area on the object to be welded. With this structure, the object to be welded can be pressurized by the first and second electrode portions without using an actuator. Further, by reducing the weight of the spot welding gun, workability can be improved.

Further, in the spot welding gun of the present invention, the operation portion rotates horizontally with respect to the fixed portion so that the axis of the operation portion substantially coincides with the center of the gap between the first and second electrode portions. freely connected. With this structure, by hollowing out the operation portion, the object to be welded can be pressed by the first and second electrode portions, and the pressure applied by the first and second electrode portions can be made uniform as much as possible. be able to.

Further, in the spot welding gun of the present invention, the axial center of the first electrode portion is eccentric with respect to the axial center of the second electrode portion before the operation portion is gouged out. With this structure, it is possible to reliably form a nugget at two points apart from each other in one welding process, thereby improving the welding strength.

In the spot welding method of the present invention, the object to be welded is inserted into the gap between the first electrode portion and the second electrode portion of the spot welding gun, and the first electrode portion faces one main surface of the object to be welded. A first pressure region to be pressed and a second pressure region to which the second electrode portion presses one main surface of the object to be welded and the other main surface on the opposite side of the object to be welded. An electric current is passed through the object to be welded while being displaced horizontally with respect to the surface, and two separated nuggets are formed in one welding process. By this spot welding method, a nugget with two welding points can be formed in one spot welding process, and the welding strength can be improved.

Further, in the spot welding method of the present invention, after the object to be welded is inserted into the gap between the first electrode portion and the second electrode portion, the operation portion is gouged, and the first electrode portion and the The second electrode portion can be rotated with respect to the object to be welded to generate a first pressure area and a second pressure area on the object to be welded. According to this spot welding method, an operator can manually pressurize the object to be welded by the first and second electrode portions. Further, the spot welding gun does not require an actuator, and the weight of the spot welding gun can be reduced, thereby improving workability.

Further, in the spot welding method of the present invention, the axial center of the first electrode portion is eccentric with respect to the axial center of the second electrode portion before the operation portion is gouged out. By this spot welding method, two nuggets can be reliably formed with a space between them, and the welding strength can be improved.

Further, in the spot welding method of the present invention, the object to be welded is formed by overlapping two plate materials, and the two-point nugget is the contact area of the two plate materials below the first pressure area and It can be formed apart from its periphery, the contact region of the two plate members above the second pressurizing region, and its periphery. By this spot welding method, it is possible to form nuggets at two welding points with a short distance therebetween in one spot welding process, thereby improving the welding strength.

Further, in the spot welding method of the present invention, the object to be welded is formed by superimposing three plate materials, and the two-point nugget is the plate material that contacts the first electrode portion below the first pressure area. and the contact area and its periphery with the plate material located in the middle, and the contact area and its periphery between the plate material in contact with the second electrode part above the second pressure area and the plate material located in the middle It can be formed spaced apart. With this spot welding method, two nuggets can be formed at a short distance in one spot welding process. In addition, the welding strength can be improved by forming nuggets at two welding points on the plate material located in the middle and on the plate materials located on the upper and lower surfaces, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view explaining the spot welding gun which is one Embodiment of this invention. It is a side view explaining the spot welding method which is one embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is (A) sectional drawing, (B) sectional drawing, (C) sectional drawing, (D) sectional drawing explaining the spot welding method which is one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view explaining the spot-welding method which is one Embodiment of this invention. It is a front view explaining the conventional spot welding gun.

First, a spot welding gun 10 and a spot welding method according to one embodiment of the present invention will be described in detail with reference to the drawings. In the description of the present embodiment, in principle, the same reference numbers are used for the same members, and repeated descriptions are omitted.

FIG. 1 is a side view illustrating a spot welding gun 10 of this embodiment. FIG. 2 is a side view for explaining a spot welding method using the spot welding gun 10 of this embodiment. 3A to 3D are cross-sectional views for explaining the spot welding method of this embodiment. FIG. 4 is a perspective view explaining the spot welding method of this embodiment.

First, the structure of the spot welding gun 10 will be described with reference to FIG. As shown, the spot welding gun 10 is used by being incorporated in a spot welding device (not shown) used in an automobile assembly line or the like. The spot welding device incorporates a transformer, a control device and a cooling device, and the spot welding gun 10 is connected to the spot welding device via a welding cable 15 and a cooling pipe 16 . Then, the operator can use the spot welding gun 10 to spot weld a desired portion of the vehicle panel 21 (see FIG. 2), which is an object to be welded.

The spot welding gun 10 mainly includes a first electrode portion 11, a second electrode portion 12 arranged to face the first electrode portion 11, the first electrode portion 11 and the second electrode. It has a fixing portion 13 that fixes and supports the portion 12 and an operation portion 14 that is connected to the fixing portion 13 .

A welding cable 15 is connected to each of the first and second electrode portions 11 and 12, and a large electric current is passed from the first electrode portion 11 to the second electrode portion 12 during welding, whereby the vehicle panel is A nugget is formed at the welding location of 21 .

The first electrode portion 11 is made of, for example, a copper alloy material having excellent electrical conductivity and thermal conductivity, and is formed in a hollow round bar shape. A cooling pipe 16 is arranged in the first electrode portion 11, and by circulating cooling water in the first electrode portion 11, the first electrode portion 11 becomes in a high temperature state during welding. excess is prevented.

The front end 11A of the first electrode portion 11 is formed, for example, in a curved shape, and as will be described in detail later, when the vehicle panel 21 is pressed, the tip 11A rotates with respect to the vehicle panel 21 so as to achieve a desired abutment. Regions can be aligned. Then, the distal end 11A of the first electrode portion 11 can press the vehicle panel 21 in the contact area with the vehicle panel 21 .

Like the first electrode portion 11, the second electrode portion 12 is also made of a copper alloy material and has a round bar shape. A cooling pipe 16 is arranged in the second electrode portion 12, and by circulating cooling water in the second electrode portion 12, the second electrode portion 12 becomes a high temperature state during welding. excess is prevented.

Further, the tip 12A of the second electrode portion 12 is also formed, for example, in a curved shape, and when the vehicle panel 21 is pressed, it rotates with respect to the vehicle panel 21 and is aligned with the desired contact area. can do. Then, the distal end 12A of the second electrode portion 12 can press the vehicle panel 21 in the contact area with the vehicle panel 21 .

As illustrated, the first and second electrode portions 11 and 12 are formed, for example, in a substantially L-shape, and are attached to the fixed portion 13 via an insulating collar 17 in regions extending in the longitudinal direction of the paper surface. is fixed. By fixing the first and second electrode portions 11 and 12 to the fixing portion 13 via the insulating collar 17, short-circuiting is prevented.

Specifically, the fixed part 13 is, for example, a round bar member made of stainless steel. The first and second electrode portions 11 and 12 are inserted into a pair of through holes (not shown) formed at regular intervals in the fixed portion 13 and supported by the fixed portion 13 . The first electrode portion 11 is arranged so that its tip 11A faces downward in the plane of the paper, and the second electrode portion 12 is arranged so that its tip 12A faces upward in the plane of the paper. there is

With this structure, the tip 11A of the first electrode portion 11 and the tip 12A of the second electrode portion 12 are separated by a constant width W1 in the thickness direction (vertical direction of the paper surface) of the vehicle panel 21 (see FIG. 2). It is fixed to the fixing portion 13 with the gap 18 therebetween. The first and second electrode portions 11 and 12 are not provided with an actuator or the like for varying the separation width W1 of the gap 18, so that the weight of the spot welding gun 10 can be reduced and workability can be improved. be able to.

The operation unit 14 is, for example, a digital torque wrench, and is arranged so as to extend in a direction perpendicular to the extending direction of the fixing unit 13 (vertical direction on the paper surface) (front-rear direction on the paper surface). A connecting portion 14</b>A is provided on the front end side of the operating portion 14 for rotatably connecting along the outer peripheral surface of the fixing portion 13 . On the other hand, on the rear end side of the operating portion 14, a grip portion 14B for the operator to operate the operating portion 14 is provided. When not in use, the operating portion 14 is fixed to the joint between the second electrode portion 12 and the welding cable 15 via an attachment/detachment lever 19 .

Further, as indicated by a dashed line, the operation portion 14 is arranged so that the axis 14C of the operation portion 14 substantially coincides with the center of the gap 18 between the first and second electrode portions 11 and 12. is connected to Due to this structure, although the details will be described later, by scooping out the operation portion 14, the first and second electrode portions 11 and 12 are connected to the front surface 21A (see FIG. 3A) and the rear surface 21B of the vehicle panel 21, respectively. (See FIG. 3A), the pressure applied to the first and second electrode portions 11 and 12 can be made uniform as much as possible.

By scooping out the operation portion 14, the first and second electrode portions 11 and 12 press the front surface 21A and the rear surface 21B of the vehicle panel 21, respectively. Then, the operation unit 14 measures the torque value at the time of pressurization, and the control device (not shown) in the spot welding apparatus determines the pressurization state from the measured value, and when the pressurization state exceeds the set value, If it is determined that there is, it is possible to apply a predetermined current between the first and second electrode portions 11 and 12 to perform spot welding. For example, as an example of passing the current, as shown in FIG. A current flows by contacting the

Next, a spot welding method using the spot welding gun 10 described above will be described with reference to FIG. As shown in the figure, the first and second electrode portions 11 and 12 are fixed by the fixing portion 13 so that the gap between the tip 11A of the first electrode portion 11 and the tip 12A of the second electrode portion 12 is 18 (see FIG. 1) has a structure in which the spacing width W1 (see FIG. 1) is not variable. The separation width W1 is designed in advance so that the object to be welded, such as the vehicle panel 21, can be reliably inserted into the gap 18. As shown in FIG. Therefore, when fixing the first and second electrode portions 11 and 12 to the fixing portion 13, arbitrary design changes are possible according to the thickness of the object to be welded.

As illustrated, the first and second electrode portions 11 and 12 are not movable in the thickness direction of the vehicle panel 21 (vertical direction on the paper surface) by an actuator or the like. Therefore, the operator first removes the attachment/detachment lever 19 (see FIG. 1) so that the operating portion 14 can rotate along the outer peripheral surface of the fixed portion 13 . After that, the operator holds the grip portion 14B of the operation portion 14, operates the spot welding gun 10, inserts the vehicle panel 21 into the gap 18 from the end of the vehicle panel 21, and separates the first and second parts. The electrode portions 11 and 12 are arranged at desired welding locations on the vehicle panel 21 .

As described above, when the vehicle panel 21 is inserted into the gap 18 between the first and second electrode portions 11 and 12, the gap width W1 (see FIG. 1) and the thickness of the vehicle panel 21 may For example, at least one of the first and second electrode portions 11 and 12 is in contact with the vehicle panel 21 and the other is out of contact with the vehicle panel 21 .

Next, the operator moves the grip portion 14B of the operation portion 14 downward, for example, as indicated by an arrow 22 in order to press the vehicle panel 21 with the first and second electrode portions 11 and 12. Gouged in a clockwise direction. By the gouging operation, the fixing portion 13 is inclined at an angle θ1 with respect to the vehicle panel 21 which is horizontal in the front-rear direction of the paper surface, and the first electrode portion 11 is tilted toward the surface 21A of the vehicle panel 21 (FIG. 3A). ), and the second electrode portion 12 rotates clockwise around the contact point until it contacts the back surface 21B of the vehicle panel 21 .

After that, while the first and second electrode portions 11 and 12 are in contact with the front surface 21A and the rear surface 21B of the vehicle panel 21, respectively, the operator moves the operation portion 14 in the direction indicated by the arrow 22. gouge the As a result, the first electrode portion 11 presses the front surface 21A of the vehicle panel 21 downward, while the second electrode portion 12 presses the back surface 21B of the vehicle panel 21 upward. .

When the operator moves the grip portion 14B of the operation portion 14 downward while gouging counterclockwise, the operator moves the grip portion 14B of the operation portion 14 upward while gouging clockwise or counterclockwise. Even in this case, similarly, a state in which the vehicle panel 21 is pressed by the first and second electrode portions 11 and 12 can be realized.

According to the operator's operation, when the measured value of the pressure applied by the first and second electrode parts 11 and 12 reaches the set condition value, the control device (not shown) in the spot welding apparatus Notifies the operator that welding is possible. Then, the operator can form a nugget with two separated welding points on the vehicle panel 21 in one welding process by applying a current for a desired period of time based on the welding conditions.

Next, a spot welding method for forming two separated nuggets in one welding process will be described with reference to FIGS. 3(A) to 3(D). 3(A) and 3(B) show the case where the vehicle panel 21 as the object to be welded is composed of two panels 21C and 21D. On the other hand, FIGS. 3(C) and 3(D) show the case where the vehicle panel 21 as the object to be welded is composed of three panels 21E, 21F and 21G. 1 and 2 will be referred to as appropriate in the following description.

First, in FIG. 3A, as indicated by the one-dot chain line 23, the first electrode part 11 and the second electrode part 12 are placed in a state in which the axial center of the first electrode part 11 and the axial center of the second electrode part 12 are substantially aligned. The portion 11 and the second electrode portion 12 face each other and are fixed by a fixing portion 13 (see FIG. 1).

As described above with reference to FIGS. 1 and 2, the operator holds the grip portion 14B of the operation portion 14 and operates the spot welding gun 10 to fill the gap 18 between the first and second electrode portions 11 and 12. , the vehicle panel 21, which is an object to be welded, is inserted. Then, the operator moves the grip portion 14B of the operation portion 14 downward and scoops it clockwise as indicated by an arrow 24, so that the first and second electrode portions 11 and 12 are attached to the vehicle. The surface 21A and the back surface 21B of the panel 21 are pressed.

As shown in FIG. 3(B), when the operator scoops out the operation portion 14, the first electrode portion 11 moves toward the vehicle panel 21 at the axis indicated by the dashed line 23 (see FIG. 3(A)). After coming into contact with the surface 21A of the vehicle panel 21, the curved tip 11A rolls rightward on the paper surface and presses the surface 21A of the vehicle panel 21 downward in the pressure area indicated by the circle 25. On the other hand, the second electrode portion 12 rotates clockwise around the pressure region indicated by the circle 25, and the second electrode portion 12 rotates in the pressure region indicated by the circle 26. The rear surface 21B of the control panel 21 is pressed upward.

As illustrated, the first and second electrode portions 11 and 12 are positioned horizontally (e.g., in the lateral direction of the drawing) with respect to the front and rear surfaces 21A and 21B of the vehicle panel 21. is pressed from above and below. Then, when the measured value of the pressure applied by the first and second electrode portions 11 and 12 reaches the set condition value, current is applied for a desired time based on the welding conditions, thereby causing the vehicle panel 21 to nuggets 28 and 29 are formed at two points apart from each other in the welding process of .

At this time, the dotted line 27 indicates the path of the current, and the current flows from the first electrode portion 11 directly below the pressurized area indicated by the circle 25, and then directly above the pressurized area indicated by the circle 26. to the second electrode portion 12 . As a result, on the vehicle panel 21, a first nugget 28 is formed directly below the pressurized area indicated by the circle 25, and a second nugget 28 is formed immediately above the pressurized area indicated by the circle 26. A nugget 29 is formed.

As described above, since the vehicle panel 21 is composed of the two panels 21C and 21D, two nuggets 28 and 29 are formed in and around the border regions of the panels 21C and 21D. The two nuggets 28 and 29 are spaced apart with a spacing width W2.

In addition, as shown in FIG. 3A, as indicated by the dashed line 23, the first electrode portion 11 and the second electrode portion 12 are substantially aligned with each other. It is not limited to the case where one electrode portion 11 and the second electrode portion 12 face each other. For example, even when the first electrode portion 11 and the second electrode portion 12 face each other in a state where the axis of the first electrode portion 11 and the axis of the second electrode portion 12 are eccentric from the beginning, good. In this case, the distance between two nuggets formed in one welding process is wider than the distance W2, but the same effect can be obtained.

Next, in FIG. 3C, as indicated by a dashed line 31, the first electrode portion 11 is aligned with the axis of the second electrode portion 12, and the first The electrode portion 11 and the second electrode portion 12 face each other and are fixed by a fixing portion 13 (see FIG. 1). As described above, the vehicle panel 21 is composed of three panels 21E, 21F, and 21G.

As shown in FIGS. 3(C) and 3(D), when the operator scoops out the operation portion 14 (see FIG. 2), the first electrode portion 11 is moved to a circle 33 as indicated by an arrow 32. The surface 21A of the vehicle panel 21 is pressed downward in the pressurizing area indicated by . On the other hand, the second electrode portion 12 presses the rear surface 21B of the vehicle panel 21 upward in the pressure area indicated by the circle 34 .

Then, when the measured value of the pressure applied by the first and second electrode portions 11 and 12 reaches the set condition value, current is applied for a desired time based on the welding conditions, thereby causing the vehicle panel 21 to nuggets 35 and 36 are formed at two points apart from each other in the welding process of .

As shown, the dotted line 37 indicates the path of the current, and the current flows from the first electrode section 11 directly below the pressure area indicated by the circle 33 and then to the pressure area indicated by the circle 34. flows from directly above to the second electrode portion 12 . As a result, a first nugget 35 is formed in and around the border regions of the panels 21E and 21F, and a second nugget 36 is formed in and around the border regions of the panels 21F and 21G. The two nuggets 35 and 36 are spaced apart to have a spacing width W3.

3(A) and 3(B), in a state where the axial center of the first electrode section 11 and the axial center of the second electrode section 12 are eccentric from the beginning, the first The electrode portion 11 and the second electrode portion 12 may face each other.

Next, a spot welding method for forming a plurality of nuggets 35 and 36 (see FIG. 3(D)) spaced apart at regular intervals at continuous welding points will be described with reference to FIG. In addition, since the welding method using continuous welding described with reference to FIG. 4 is realized by repeating one welding process described with reference to FIGS. will be described with reference to FIGS. 1 to 3 as appropriate.

FIG. 4 shows, for example, a frame member 41 forming part of the frame of a vehicle (not shown), and the frame member 41 is composed of three panels 42 , 43 and 44 . As shown in the figure, the frames 42 and 44 are pressed to have a substantially U-shaped cross section, and welded regions 45 and 46 are formed at both ends thereof. On the other hand, the frame 43 is a plate-like body and is arranged between the frames 42 and 44 to increase the strength of the frame member 41 .

In the welding regions 45 and 46 of the frame member 41, three frames 42, 43 and 44 are arranged in an overlapping manner. As described above with reference to FIGS. 3(C) and 3(D), the operator operates the operating portion 14 (see FIG. 1) of the spot welding gun 10 (see FIG. 1) to make the solid-line circle As indicated by a mark 47 , the first electrode portion 11 (see FIG. 1) of the spot welding gun 10 presses the surface 41A side of the frame member 41 . On the other hand, on the rear surface 41B side of the frame member 41, the second electrode portion 12 (see FIG. 1) of the spot welding gun 10 is similarly positioned on the rear surface 41B side of the frame member 41, as indicated by the dotted circle 48. pressurize. The pressurized regions indicated by circles 47 and 48 are pressurized portions by the first and second electrode portions 11 and 12 at the time of continuous hitting. They are arranged with a width of W4.

Then, by applying a current in the pressurized state by the first and second electrode portions 11 and 12, the first nugget 35 (see FIG. 3(D)) is moved to the panel 44 directly below the circle 47, A second nugget 36 (see FIG. 3(D)) is formed in and around the border areas of panels 43 and 42 just above circle 48 . At this time, by providing a separation width W5 between the adjacent nuggets 35 and 36 of, for example, about 20 mm, when forming a new nugget 35, the current at the time of welding is diverted to the nugget 36 at the already hit point, and a new nugget 35 is formed. A situation in which the nugget 35 cannot be formed can be prevented.

As a result, the operator once inserts the welding regions 45, 46 of the frame member 41 into the gap 18 (see FIG. 1) between the first and second electrode portions 11, 12 of the spot welding gun 10, and then Spot welding by continuous spot welding can be performed while the spot welding gun 10 is slid in the extending direction of the frame member 41 while keeping the widths W4 and W5. The worker can improve work efficiency by the welding work by repeating the above. Furthermore, the number of nuggets 35, 36 formed in the welding regions 45, 46 can be increased compared to conventional one-point spot welding, and the welding strength can be increased.

In the present embodiment, the first and second electrode portions 11 and 12 are fixed via the fixing portion 13, and the operator can gouge the operating portion 14 connected to the fixing portion 13 so as to Although the case of forming a nugget with two welding points in one welding process has been described, the present invention is not limited to this case. For example, the spot welding gun 10 may be arranged at the tip of an arm of a welding robot, and the arm may perform a scooping operation to form a nugget with two welding points in one welding process.

Further, the first and second electrode portions 11 and 12 are fixed to the fixing portion 13 with a constant separation width W1, and at least one of the first or second electrode portions 11 and 12 is Although the case where the actuator does not move has been described, the present invention is not limited to this case. In the spot welding gun 10 of the welding device, for example, at least one of the first or second electrode portions 11 and 12 is vertically movable with respect to the front surface 21A or the rear surface 21B of the vehicle panel 21 by an actuator, The axial center of the first electrode portion 11 and the axial center of the second electrode portion 12 are horizontally eccentric with respect to the front surface 21A or the rear surface 21B of the vehicle panel 21 . Then, by driving the actuator in the vertical direction, the first and second electrode portions 11 and 12 pressurize the front surface 21A and the rear surface 21B of the vehicle panel 21, and current is supplied to the vehicle panel 21. In the spot welding process, the nugget may be formed with two points separated from each other. In addition, various modifications are possible without departing from the gist of the present invention.

REFERENCE SIGNS LIST 10 spot welding gun 11 first electrode portion 12 second electrode portion 13 fixing portion 14 operation portion 14B grip portion 15 welding cable 16 cooling pipe 18 gap 19 attachment/detachment lever 21 vehicle panel 21C, 21D, 21E, 21F, 21G Panel 28, 29, 35, 36 Nugget

Claims (9)

A spot welding gun comprising a first electrode section and a second electrode section arranged facing each other with a gap for inserting an object to be welded,
a fixing portion that fixes the first electrode portion and the second electrode portion while maintaining the gap;
By gouging the fixing portion in one direction, the first electrode portion presses a first pressure region on one main surface of the object to be welded, and the second electrode portion presses the pressurizing a second pressurizing region of the main surface opposite to the one main surface of the object to be welded;
current is applied to the object to be welded in a state in which the first pressure region and the second pressure region are horizontally shifted with respect to the one main surface of the object to be welded; A spot welding gun characterized by performing spot welding. Further comprising an operation part that is connected to the fixed part and that operates the first electrode part and the second electrode part,
By gouging the operation portion, the first electrode portion and the second electrode portion are rotated with respect to the object to be welded via the fixing portion, and the first pressure is applied to the object to be welded. 2. The spot welding gun of claim 1, wherein a zone and said second pressure zone are generated. The operation part is connected to the fixing part so as to be rotatable in the horizontal direction so that the axis of the operation part substantially coincides with the center of the gap. Spot welding gun as described. 4. The method according to claim 2, wherein the axial center of the first electrode portion is eccentric with respect to the axial center of the second electrode portion in a state before the operation portion is gouged. spot welding gun. The object to be welded is inserted into the gap between the first electrode portion and the second electrode portion of the spot welding gun, and the object to be welded is pressed by the first electrode portion and the second electrode portion. A spot welding method for welding the object to be welded by applying a current in a state of
The spot welding gun is
a fixing portion that fixes the first electrode portion and the second electrode portion while maintaining the gap;
After inserting the object to be welded into the gap between the first electrode portion and the second electrode portion, the fixing portion is scooped out in one direction, thereby separating the first electrode portion and the second electrode portion. Rotating the electrode part with respect to the object to be welded,
A first pressurizing region where the first electrode portion presses one main surface of the object to be welded, and a second electrode portion on the other side opposite to the one main surface of the object to be welded. A current is applied to the object to be welded in a state in which a second pressure area for applying pressure to the main surface is horizontally shifted with respect to the one main surface of the object to be welded, and one welding process is performed. A spot welding method characterized by forming a nugget of two points spaced apart by. The spot welding gun is
Further comprising an operation part that is connected to the fixed part and that operates the first electrode part and the second electrode part,
After inserting the object to be welded into the gap between the first electrode portion and the second electrode portion, the operation portion is gouged, and the first electrode portion and the second electrode portion are welded via the fixing portion. 6. The electrode part of claim 5 is rotated with respect to the object to be welded to generate the first pressure area and the second pressure area on the object to be welded. spot welding method. 7. The spot welding method according to claim 6, wherein the axial center of the first electrode portion is eccentric with respect to the axial center of the second electrode portion before the operation portion is gouged. . The object to be welded is formed by overlapping two plate materials,
The two-point nugget includes a contact area of the two plate materials below the first pressure area and its surroundings, and a contact area of the two plate materials above the second pressure area and its surroundings. 8. The spot welding method according to any one of claims 5 to 7, wherein the spot welding method is formed so as to be spaced apart from the periphery. The object to be welded is formed by stacking three plate materials,
The two-point nugget includes a contact area between the plate material that contacts the first electrode part below the first pressure area and the plate material that is positioned in the middle, and the surrounding area of the contact area, and the second pressure area. 5 to 5, characterized in that it is formed apart from a contact region between the plate member in contact with the second electrode part above the region and the plate member located in the middle and the periphery thereof. 8. The spot welding method according to any one of 7.

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