Resistance welding device and resistance welding method

Abstract

This resistance welding device 1 comprises a first electrode 10, a second electrode 20 that moves so as to approach or separate from the first electrode in a first direction Z, and a conductive adapter 30 that moves in a second direction X intersecting the first direction. The adapter enters a first position P1 between the first electrode and the second electrode by moving to one side Xa in the second direction, and retreats to a second position P2 separated from the first position by moving to the other side Xb in the second direction. The adapter includes a base part 31 extending in the first direction, a first extension part 36 extending from a first electrode side in the first direction of the base part to one side in the second direction, and a second extension part 37 extending from a second electrode side in the first direction of the base part to one side in the second direction.

Description

Resistance welding device and resistance welding method

[0001] The present disclosure relates to a resistance welding device and a resistance welding method.

[0002] As shown in Patent Document 1, a resistance welding device for joining a fastening member to a work is known.

[0003] Japanese Patent Application Laid-Open No. 2023-003128

[0004] By the way, there is a work formed such that a pair of side walls stand up from the bottom wall. In the resistance welding device disclosed in Patent Document 1, it may be possible to join a fastening member to the inner surface of the bottom wall of such a work, but it is not possible to join a fastening member to the inner surface of the side wall of such a work. Conventionally, when attempting to join a fastening member to the bottom wall and side wall of a work, at least two or more resistance welding machines having different types of electrodes were required.

[0005] An object of the present disclosure is to provide a resistance welding device capable of joining a fastening member to the bottom wall and side wall of a work.

[0006] The resistance welding device according to the present disclosure includes a first electrode, a second electrode that moves closer to and away from the first electrode in a first direction, and a conductive adapter that moves in a second direction intersecting the first direction. The adapter enters a first position between the first electrode and the second electrode by moving to one side in the second direction, and retreats to a second position away from the first position by moving to the other side in the second direction. The adapter includes a base portion extending in the first direction, a first extension portion extending from the side of the first electrode in the first direction of the base portion to the one side in the second direction, and a second extension portion extending from the side of the second electrode in the first direction of the base portion to the one side in the second direction.

[0007] Assume there is a workpiece formed such that a pair of side walls are erected from the bottom wall. At this time, the workpiece is positioned facing the adapter in a second direction, and the adapter is inserted into a first position between the first electrode and the second electrode. As a result, the fastening member can be joined to the inner surface of the side wall of the workpiece by the first electrode, the second electrode, and the adapter.

[0008] Furthermore, the workpiece is positioned so that it is open to either the first electrode or the second electrode in the first direction, and the adapter is retracted to a second position away from the first position. This allows the fastening member to be joined to the bottom inner surface of the bottom wall of the workpiece by the first and second electrodes.

[0009] In summary, we can provide a resistance welding apparatus capable of joining fastening members to the bottom wall and side wall of a workpiece.

[0010] In one embodiment, the adapter is U-shaped, C-shaped, V-shaped, or U-shaped, opening to one side in the second direction.

[0011] This allows for the creation of a suitable adapter shape.

[0012] In one embodiment, a protrusion is provided on at least one of the first outer surface of the first extension, which is the surface on the side of the first electrode, and the second outer surface of the second extension, which is the surface on the side of the second electrode.

[0013] This makes it easier to bring the adapter into contact with the first electrode and / or the second electrode.

[0014] In one embodiment, the adapter is movable in the first direction.

[0015] The adapter's position can be finely adjusted in the first direction.

[0016] In one embodiment, the first direction is the vertical direction, the first electrode is positioned below the second electrode, and the second electrode is positioned above the first electrode.

[0017] This facilitates the layout of the first and second electrodes in a resistance welding apparatus.

[0018] The resistance welding method according to the present disclosure is a resistance welding method for resistance welding a workpiece and a fastening member using the resistance welding apparatus, wherein the workpiece includes a bottom wall, a first side wall erected on the bottom wall, and a second side wall erected on the bottom wall at a position separate from the first side wall, and the resistance welding method performs a first mode in which the adapter is in the first position, in which the workpiece is positioned open to the adapter in the second direction, the first side wall of the workpiece is positioned on the side of the first electrode and the second side wall of the workpiece is positioned on the side of the second electrode, and the first side wall of the workpiece and the fastening member are resist-welded to each other by applying pressure between the first electrode and the second electrode via the adapter, and by passing current between the first electrode and the second electrode via the first side wall of the workpiece, the fastening member, the first extension of the adapter and the second extension of the adapter.

[0019] In one embodiment, a second mode is performed in which the adapter is in the second position, in which the workpiece is positioned facing the second electrode in the first direction, and the bottom wall of the workpiece and the fastening member are pressed together by the first electrode and the second electrode, and current is passed between the first electrode and the second electrode through the bottom wall of the workpiece and the fastening member to join the bottom inner surface of the bottom wall of the workpiece and the fastening member together.

[0020] According to this disclosure, a resistance welding apparatus capable of joining fastening members to the bottom wall and side wall of a workpiece can be provided.

[0021] Figure 1 shows a resistance welding apparatus according to the first embodiment. Figure 2 shows a workpiece. Figure 3 shows a fastening member. Figure 4 shows the pre-process of the second mode of the resistance welding method according to the first embodiment. Figure 5 shows the post-process of the second mode of the resistance welding method according to the first embodiment. Figure 6 shows the pre-process of the first mode of the resistance welding method according to the first embodiment. Figure 7 shows the first intermediate process of the first mode of the resistance welding method according to the first embodiment. Figure 8 shows the second intermediate process of the first mode of the resistance welding method according to the first embodiment. Figure 9 shows the post-process of the first mode of the resistance welding method according to the first embodiment. Figure 10 shows a resistance welding apparatus according to the second embodiment. Figure 11 shows a resistance welding apparatus according to a comparative example.

[0022] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The following description of preferred embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses in any way.

[0023] <First Embodiment> The first embodiment will be described below.

[0024] (Resistance Welding Apparatus) Figure 1 shows a resistance welding apparatus 1. The resistance welding apparatus 1 comprises a lower holder 2, an upper holder 3, a first actuator 4, a guide pin 5, a second actuator 6, a coil spring 7, a lower electrode 10, an upper electrode 20, and an adapter 30. The lower electrode 10 is an example of a first electrode. The upper electrode 20 is an example of a second electrode.

[0025] The lower holder 2 is cylindrical and extends in the vertical direction Z. The vertical direction Z is an example of a first direction. The lower holder 2 is positioned below the upper holder 3 in a direction Za. The lower holder 2 is fixed in place.

[0026] The lower electrode 10 is held in the lower holder 2. The lower electrode 10 extends in the vertical direction Z. The lower electrode 10 protrudes upward Zb from the upper end of the lower holder 2. The lower electrode 10 is positioned lower Za than the upper electrode 20. The lower electrode 10 is fixed in place. The upper end 11 (tip) of the lower electrode 10 faces upward Zb. The lower electrode 10 is made of, for example, metal.

[0027] A guide pin 5 is housed inside the lower electrode 10. The guide pin 5 extends in the vertical direction Z. The guide pin 5 moves in the vertical direction Z inside the lower electrode 10 by an actuator (not shown). The guide pin 5 protrudes upward Zb from the upper end 11 of the lower electrode 10, or retracts downward Za relative to the upper end 11 of the lower electrode 10.

[0028] The upper holder 3 is cylindrical and extends in the vertical direction Z. The upper holder 3 is positioned above the lower holder 2, at a position Zb above it. The upper holder 3 moves closer to and away from the lower holder 2 in the vertical direction Z. The vertical movement of the upper holder 3 in the vertical direction Z is performed, for example, by an electrically powered or pneumatic first actuator 4.

[0029] The upper electrode 20 is held in the upper holder 3. The upper electrode 20 extends in the vertical direction Z. The upper electrode 20 protrudes downward Za from the lower end of the upper holder 3. The upper electrode 20 is positioned above Zb above the lower electrode 10. The lower end 21 (tip) of the upper electrode 20 faces downward Za. The upper electrode 20 moves towards and away from the lower electrode 10 in the vertical direction Z. The upper end 11 of the lower electrode 10 and the lower end 21 of the upper electrode 20 face each other in the vertical direction Z. The upper electrode 20 is made of, for example, metal.

[0030] The adapter 30 is conductive. The adapter 30 is made of metal. The adapter 30 moves in the front-rear direction X. The front-rear direction X is an example of a second direction. The front-rear direction X intersects with the up-down direction Z. The front-rear direction X may also be perpendicular to the up-down direction Z. In addition to the front-rear direction X, the left-right direction Y (the direction perpendicular to the plane of the paper in Figure 1) is another direction that intersects with the up-down direction Z. The front-rear direction X and the left-right direction Y constitute the horizontal direction.

[0031] The adapter 30 includes a base portion 31, a first extension portion 36, and a second extension portion 37. The base portion 31 extends in the vertical direction Z.

[0032] The first extension 36 extends from the lower end 31a of the base portion 31 on the side of the lower electrode 10 in the vertical direction Z to the front side Xa in the front-rear direction X. The second extension 37 extends from the upper end 31b of the base portion 31 on the side of the upper electrode 20 in the vertical direction Z to the front side Xa in the front-rear direction X. The front side Xa is an example of one side. The rear side Xb, which will be described later, is an example of the other side.

[0033] The first extension 36 is located on the side of the lower electrode 10 (lower side Za) in the vertical direction Z relative to the second extension 37. The second extension 37 is located on the side of the upper electrode 20 (upper side Zb) in the vertical direction Z relative to the first extension 36.

[0034] The first extension 36 and the second extension 37 are separated from each other in the vertical direction Z. The first extension 36 and the second extension 37 face each other in the vertical direction Z and extend in the front-rear direction X. The first extension 36 and the second extension 37 may extend parallel to each other. The first extension 36 and the second extension 37 may extend geometrically parallel to each other.

[0035] The first inner surface 36a of the first extension 36 faces the upper side Zb. In the first extension 36, the first outer surface 36b is on the opposite side from the first inner surface 36a in the vertical direction Z. The first outer surface 36b of the first extension 36 faces the lower side Za. The second inner surface 37a of the second extension 37 faces the lower side Za. In the second extension 37, the second outer surface 37b is on the opposite side from the second inner surface 37a in the vertical direction Z. The second outer surface 37b of the second extension 37 faces the upper side Zb.

[0036] The first outer surface 36b of the first extension 36 (the surface on the side of the lower electrode 10) is provided with a protrusion 38 that projects downward to Za. The first outer surface 36b is the surface of the first extension 36 on the side of the lower electrode 10.

[0037] The first inner surface 36a of the first extension 36 and the second inner surface 37a of the second extension 37 face each other in the vertical direction Z.

[0038] The rear surface of the base portion 31 of the adapter 30 is provided with a first guide 39a, a second guide 39b, and a pin 39c.

[0039] The first guide 39a is disposed on the lower side Za with respect to the second guide 39b. The first guide 39a extends in the front-rear direction X. The second guide 39b is disposed on the upper side Zb with respect to the first guide 39a. The second guide 39b extends in the front-rear direction X. The first guide 39a and the second guide 39b extend in parallel (specifically, geometrically parallel) in the front-rear direction X while facing each other in the vertical direction Z.

[0040] The pin 39c is disposed between the first guide 39a and the second guide 39b. The pin 39c connects the first guide 39a and the second guide 39b. The pin 39c extends in the vertical direction Z.

[0041] A coil spring 7 is wound around the pin 39c. The coil spring 7 is an example of a biasing portion. The coil spring 7 is an elastic member. The coil spring 7 is provided between the second guide 39b and a rod 6a described later.

[0042] The adapter 30 is U-shaped, C-shaped, V-shaped, or U-shaped and open at the front side Xa in the front-rear direction X. In this example, the adapter 30 is particularly close to a U-shape. The U-shape is a shape similar to the Japanese katakana character "U".

[0043] The adapter 30 is moved in the front-rear direction X by the second actuator 6. The second actuator 6 includes a rod 6a and a drive mechanism 6b. The rod 6a extends in the front-rear direction X.

[0044] The front end portion of the rod 6a contacts the rear surface of the base portion 31 of the adapter 30. The rod 6a is provided with a pin hole (not shown) penetrating in the vertical direction Z. The pin 39c of the adapter 30 passes through the pin hole of the rod 6a.

[0045] The coil spring 7 is disposed between the second guide 39b and the rod 6a. When the coil spring 7 is in an unloaded state where no load is applied to the coil spring 7, the coil spring 7 presses the second guide 39b of the adapter 30 upward in the upper side Zb. The coil spring 7 biases the second guide 39b upward in the upper side Zb, which is the side of the upper electrode 20 in the vertical direction Z, by an elastic force I (biasing force).

[0046] The rear end portion of the rod 6a is accommodated in the drive mechanism 6b. The rod 6a moves (extends and contracts) in the front-rear direction X by the drive of the drive mechanism 6b. The rod 6a advances to the front side Xa in the front-rear direction X and retreats to the rear side Xb in the front-rear direction X by the drive mechanism 6b. The drive mechanism 6b is, for example, electric or pneumatic.

[0047] The adapter 30 enters the first position P1 between the lower electrode 10 and the upper electrode 20 by moving to the front side Xa in the front-rear direction X, and retreats to the second position P2 away from the first position P1 by moving to the rear side Xb in the front-rear direction X. The first position P1 is located farther to the front side Xa than the second position P2. The second position P2 is located farther to the rear side Xb than the first position P1.

[0048] (Workpiece) FIG. 2 shows a workpiece 40. The workpiece 40 includes a bottom wall 41, a first side wall 46, and a second side wall 47. The bottom wall 41 is plate-shaped in the thickness direction T. The bottom wall 41 extends in the longitudinal direction E and the lateral direction F. The thickness direction T, the longitudinal direction E, and the lateral direction F intersect (specifically, are orthogonal) to each other. In this example, the dimension of the bottom wall 41 in the longitudinal direction E is larger than the dimension of the bottom wall 41 in the lateral direction F.

[0049] The first side wall 46 is erected at one end portion Fa in the lateral direction F of the bottom inner surface 41a of the bottom wall 41. The first side wall 46 is plate-shaped with the lateral direction F as the thickness direction. The first side wall 46 extends in the thickness direction T and the longitudinal direction E of the bottom wall 41.

[0050] The second side wall 47 is erected at the other end portion Fb in the lateral direction F of the bottom inner surface 41a of the bottom wall 41. In the lateral direction F, the other end portion Fb is at a position separated from the one end portion Fa. The second side wall 47 is erected on the bottom wall 41 at a position separated from the first side wall 46 in the lateral direction F. In other words, the first side wall 46 is erected on the bottom wall 41 at a position separated from the second side wall 47 in the lateral direction F. The second side wall 47 is plate-shaped with the lateral direction F as the thickness direction. The second side wall 47 extends in the thickness direction T and the longitudinal direction E of the bottom wall 41.

[0051] In the bottom wall 41, the bottom inner surface 41a is the surface on which the first side wall 46 and the second side wall 47 are erected. In the bottom wall 41, the bottom outer surface 41b is the surface on the opposite side from the side on which the first side wall 46 and the second side wall 47 are erected. The bottom outer surface 41b of the bottom wall 41 does not have the first side wall 46 and the second side wall 47. In the thickness direction T of the bottom wall 41, the bottom inner surface 41a and the bottom outer surface 41b are on opposite sides of each other.

[0052] The first side wall 46 and the second side wall 47 are separated from each other in the lateral direction F. The first side wall 46 and the second side wall 47 face each other in the lateral direction F and extend in the thickness direction T and the longitudinal direction E of the bottom wall 41. The first side wall 46 and the second side wall 47 may extend parallel to each other. The first side wall 46 and the second side wall 47 may extend geometrically parallel to each other.

[0053] The first inner surface 46a of the first side wall 46 and the second inner surface 47a of the second side wall 47 face each other in the lateral direction F. In the first side wall 46, the first outer surface 46b is on the opposite side from the first inner surface 46a in the lateral direction F. In the second side wall 47, the second outer surface 47b is on the opposite side from the second inner surface 47a in the lateral direction F.

[0054] The first inner surface 46a of the first side wall 46 is the surface facing the second inner surface 47a of the second side wall 47. The first outer surface 46b of the first side wall 46 is the surface facing the opposite side of the second inner surface 47a of the second side wall 47. The second inner surface 47a of the second side wall 47 is the surface facing the first inner surface 46a of the first side wall 46. The second outer surface 47b of the second side wall 47 is the surface facing the opposite side of the first inner surface 46a of the first side wall 46.

[0055] The workpiece 40 is U-shaped, C-shaped, V-shaped, or U-shaped, with one end open. In this example, the workpiece 40 is particularly close to U-shaped. The U-shape is similar in shape to the Japanese katakana character "コ". The workpiece 40 is made of, for example, metal. The workpiece 40 is formed, for example, by pressing a metal sheet.

[0056] Holes 48 are drilled in the bottom wall 41. Holes 48 are drilled in the first side wall 46. Holes 48 are drilled in the second side wall 47. Multiple holes 48 are arranged in a line in the vertical direction E. As will be described later, guide pins 5 are passed through the holes 48.

[0057] (Fastening Member) Figure 3 shows a fastening member 50. In this example, the fastening member 50 is a nut. The fastening member 50 has a main body 51 and four protrusions 52. In this example, the main body 51 is formed in the shape of a rectangular prism. The four protrusions 52 are provided at the four corners of the bottom surface of the main body 51. A through hole 53 is provided in the center of the main body 51. The through hole 53 penetrates the center of the main body 51. The through hole 53 is, for example, a screw hole. The fastening member 50 is made of, for example, metal.

[0058] (Resistance Welding Method) The resistance welding method will now be explained. In the resistance welding method, the workpiece 40 and the fastening member 50 are resist-welded using a resistance welding apparatus 1. The resistance welding method is performed in first mode M1 and second mode M2.

[0059] (Second Mode) Figure 4 shows the pre-processing steps of the second mode M2 ​​of the resistance welding method. Figure 5 shows the post-processing steps of the second mode M2 ​​of the resistance welding method. The resistance welding method performs the second mode M2.

[0060] In the second mode M2, first, the upper electrode 20 is moved to the upper side Zb, moving the upper electrode 20 away from the lower electrode 10.

[0061] In the second mode M2, the adapter 30 is in the second position P2. In the second mode M2, the adapter 30 is positioned in the second position P2. In the second mode M2, the adapter 30 is moved to the rear Xb in the front-rear direction X, thereby causing the adapter 30 to retract to the second position P2.

[0062] In the second mode M2, the orientation of the workpiece 40 is adjusted so that the bottom inner surface 41a of the bottom wall 41 faces the upper side Zb and the first side wall 46 and the second side wall 47 (which are erected on the bottom inner surface 41a of the bottom wall 41) extend from the lower side Za to the upper side Zb. In the second mode M2, the workpiece 40 is positioned so that it is open to the side of the upper electrode 20 (upper side Zb) in the vertical direction Z.

[0063] In the second mode M2, the guide pin 5 protrudes from the upper end 11 of the lower electrode 10 to the upper side Zb.

[0064] In the second mode M2, the bottom outer surface 41b of the bottom wall 41 of the workpiece 40 is placed on the upper end 11 of the lower electrode 10. Specifically, the bottom outer surface 41b of the bottom wall 41 of the workpiece 40 is placed on the upper end 11 of the lower electrode 10. The bottom outer surface 41b of the bottom wall 41 of the workpiece 40 is in contact with the upper end 11 of the lower electrode 10.

[0065] In the second mode M2, a guide pin 5 protruding upward Zb from the upper end 11 of the lower electrode 10 is passed through a hole 48 drilled in the bottom wall 41 of the workpiece 40. At this time, the upper end of the guide pin 5 is positioned upward Zb above the bottom inner surface 41a of the bottom wall 41 of the workpiece 40.

[0066] In the second mode M2, the through hole 53 of the fastening member 50 is hooked onto the guide pin 5. At this time, the main body portion 51 of the fastening member 50 is positioned on the upper Zb side and the projection 52 is positioned on the lower Za side. The fastening member 50 is positioned on the upper Zb side above the bottom inner surface 41a of the bottom wall 41 of the workpiece 40. The projection 52 of the fastening member 50 contacts the bottom inner surface 41a of the bottom wall 41 of the workpiece 40. The upper end of the guide pin 5 may be positioned on the upper Zb side above the upper surface of the main body portion 51 of the fastening member 50.

[0067] In the second mode M2, the upper electrode 20 is moved to the lower side Za, bringing it closer to the lower electrode 10. The lower end 21 of the upper electrode 20 is brought into contact with the upper end of the guide pin 5. While moving the upper electrode 20 further to the lower side Za, the guide pin 5 is retracted to the lower side Za. As a result, the lower end 21 of the upper electrode 20 comes into contact with the upper surface of the main body 51 of the fastening member 50.

[0068] Between the upper end 11 of the lower electrode 10 and the lower end 21 of the upper electrode 20, the bottom wall 41 of the workpiece 40 and the fastening member 50 are interposed. The projection 52 of the fastening member 50 is in contact with the bottom inner surface 41a of the bottom wall 41 of the workpiece 40. More precisely, the projection 52 makes contact due to the pressure applied as described later.

[0069] In the second mode M2, the bottom wall 41 of the workpiece 40 and the fastening member 50 are pressed together by the lower electrode 10 and the upper electrode 20, and current is passed between the lower electrode 10 and the upper electrode 20 through the bottom wall 41 of the workpiece 40 and the fastening member 50, thereby joining the bottom inner surface 41a of the bottom wall 41 of the workpiece 40 and the fastening member 50 to each other.

[0070] (First Mode) Figure 6 shows the pre-process of the first mode M1 of the resistance welding method. Figure 7 shows the first intermediate process of the first mode M1 of the resistance welding method. Figure 8 shows the second intermediate process of the first mode M1 of the resistance welding method. Figure 9 shows the post-process of the first mode M1 of the resistance welding method. The resistance welding method performs the first mode M1.

[0071] In the first mode M1, first, the upper electrode 20 is moved to the upper side Zb, moving the upper electrode 20 away from the lower electrode 10.

[0072] In the first mode M1, the orientation of the workpiece 40 is adjusted so that the first side wall 46 is located on the lower side Za and the second side wall 47 is located on the upper side Zb. At this time, the bottom wall 41 extends in the vertical direction Z. The first inner surface 46a of the first side wall 46 faces the upper side Zb. The first outer surface 46b of the first side wall 46 faces the lower side Za. The second inner surface 47a of the second side wall 47 faces the lower side Za. The second outer surface 47b of the second side wall 47 faces the upper side Zb.

[0073] In the first mode M1, the workpiece 40 is positioned with its rear Xb side (the side of the adapter 30) open in the front-rear direction X.

[0074] In the first mode M1, the first side wall 46 of the workpiece 40 is positioned on the lower side Za (the side of the lower electrode 10), and the second side wall 47 of the workpiece 40 is positioned on the upper side Zb (the side of the upper electrode 20).

[0075] In the first mode M1, the guide pin 5 protrudes from the upper end 11 of the lower electrode 10 to the upper side Zb.

[0076] In the first mode M1, the first outer surface 46b of the first side wall 46 of the workpiece 40 is placed on the upper end 11 of the lower electrode 10. Specifically, the first outer surface 46b of the first side wall 46 of the workpiece 40 is placed on the upper end 11 of the lower electrode 10. The first outer surface 46b of the first side wall 46 of the workpiece 40 is in contact with the upper end 11 of the lower electrode 10.

[0077] In the first mode M1, a guide pin 5 protruding upward Zb from the upper end 11 of the lower electrode 10 is passed through a hole 48 drilled in the first side wall 46 of the workpiece 40. At this time, the upper end of the guide pin 5 is positioned upward Zb above the first inner surface 46a of the first side wall 46 of the workpiece 40.

[0078] In the first mode M1, the through hole 53 of the fastening member 50 is hooked onto the guide pin 5. At this time, the main body portion 51 of the fastening member 50 is positioned on the upper Zb side and the projection 52 is positioned on the lower Za side. The fastening member 50 is positioned on the upper Zb side above the first inner surface 46a of the first side wall 46 of the workpiece 40. The projection 52 of the fastening member 50 contacts the first inner surface 46a of the first side wall 46 of the workpiece 40. The upper end of the guide pin 5 may be positioned on the upper Zb side above the upper surface of the main body portion 51 of the fastening member 50.

[0079] In the first mode M1, the adapter 30 is in the first position P1. In the first mode M1, the adapter 30 is positioned in the first position P1. In the first mode M1, the adapter 30 is moved forward Xa in the front-rear direction X, thereby moving the adapter 30 into the first position P1 between the lower electrode 10 and the upper electrode 20. The adapter 30 enters between the first side wall 46 and the second side wall 47 of the workpiece 40.

[0080] In the first mode M1, the adapter 30, which is open to the front Xa, and the workpiece 40, which is open to the rear Xb, engage with each other.

[0081] In the first mode M1, the protrusion 38 on the first outer surface 36b of the first extension 36 of the adapter 30 is positioned on the upper end of the guide pin 5 (located above Zb above the upper surface of the main body 51 of the fastening member 50). The protrusion 38 on the first outer surface 36b of the first extension 36 of the adapter 30 contacts the upper end of the guide pin 5.

[0082] In the first mode M1, the upper electrode 20 is moved to the lower side Za, bringing it closer to the lower electrode 10. The lower end 21 of the upper electrode 20 contacts the second outer surface 37b of the second extension 37 of the adapter 30.

[0083] At this time, a gap is formed between the first inner surface 36a of the first extension 36 of the adapter 30 and the second inner surface 47a of the second side wall 47 of the workpiece 40. A gap is also formed between the second inner surface 37a of the second extension 37 of the adapter 30 and the second outer surface 47b of the second side wall 47 of the workpiece 40. These gaps are optional.

[0084] In the first mode M1, the upper electrode 20 is moved further downward to Za while the guide pin 5 is retracted downward to Za. The first outer surface 46b of the first side wall 46 of the workpiece 40 contacts the upper end 11 of the lower electrode 10. The projection 52 of the fastening member 50 contacts the first inner surface 46a of the first side wall 46 of the workpiece 40. The convex portion 38 of the first outer surface 36b of the first extension 36 of the adapter 30 contacts the upper surface of the main body 51 of the fastening member 50. The lower end 21 of the upper electrode 20 contacts the second outer surface 37b of the second extension 37 of the adapter 30.

[0085] In the first mode M1, the upper electrode 20 presses the second extension 37 of the adapter 30 against the lower side Za by a pressing force J. In the first mode M1, the upper electrode 20 moves the adapter 30 to the lower side Za against the elastic force I applied to the upper side Zb by the coil spring 7. That is, the adapter 30 is movable in the vertical direction Z.

[0086] Between the upper end 11 of the lower electrode 10 and the lower end 21 of the upper electrode 20, the first side wall 46 of the workpiece 40, the fastening member 50, and the adapter 30 are interposed. The projection 52 of the fastening member 50 is in contact with the first inner surface 46a of the first side wall 46 of the workpiece 40. More precisely, the projection 52 makes contact due to the pressure described later.

[0087] In the first mode M1, the first side wall 46 of the workpiece 40 and the fastening member 50 are pressurized by the lower electrode 10 and the upper electrode 20 via the adapter 30.

[0088] In the first mode M1, current is supplied between the lower electrode 10 and the upper electrode 20 via the first side wall 46 of the workpiece 40, the fastening member 50, the first extension 36 of the adapter 30, the base portion 31 of the adapter 30, and the second extension 37 of the adapter 30.

[0089] In the first mode M1, the first inner surface 46a of the first side wall 46 of the workpiece 40 and the fastening member 50 are resistance welded to each other.

[0090] In summary, in the first mode M1, the first side wall 46 of the workpiece 40 and the fastening member 50 are resist-welded to each other by applying pressure to them with the lower electrode 10 and the upper electrode 20 via the adapter 30, while current is passed between the lower electrode 10 and the upper electrode 20 via the first side wall 46 of the workpiece 40, the fastening member 50, the first extension 36 of the adapter 30, the base portion 31 of the adapter 30, and the second extension 37 of the adapter 30.

[0091] If you want to join the fastening member 50 to the second inner surface 47a of the second side wall 47 of the workpiece 40, you can perform the same procedure as described above with the second side wall 47 of the workpiece 40 positioned on the lower side Za (the side of the lower electrode 10) and the first side wall 46 of the workpiece 40 positioned on the upper side Zb (the side of the upper electrode 20).

[0092] (Effects) Assume there is a workpiece 40 formed such that a pair of first side walls 46 and second side walls 47 are erected from a bottom wall 41.

[0093] At this time, the workpiece 40 is positioned so that it is open to the side of the adapter 30 (rear side Xb) in the front-rear direction X. The position of the workpiece 40 is also adjusted so that the first side wall 46 is located on the lower side Za and the second side wall 47 is located on the upper side Zb. The adapter 30 is then inserted into the first position P1 between the lower electrode 10 and the upper electrode 20.

[0094] The first side wall 46 of the workpiece 40 and the fastening member 50 are resist-welded to each other by applying pressure to them with the lower electrode 10 and the upper electrode 20 via the adapter 30, while current is passed between the lower electrode 10 and the upper electrode 20 via the first side wall 46 of the workpiece 40, the fastening member 50, the first extension 36 of the adapter 30, the base 31 of the adapter 30, and the second extension 37 of the adapter 30.

[0095] As a result, the lower electrode 10, the upper electrode 20, and the adapter 30 can join the fastening member 50 to the first inner surface 46a of the first side wall 46 of the workpiece 40.

[0096] Furthermore, the workpiece 40 is positioned so that it is open to the side of the upper electrode 20 (upper Zb) in the vertical Z direction. Also, the adapter 30 is retracted to a second position P2, which is away from the first position P1.

[0097] The bottom wall 41 of the workpiece 40 and the fastening member 50 are pressed together by the lower electrode 10 and the upper electrode 20, and current is passed between the lower electrode 10 and the upper electrode 20 through the bottom wall 41 of the workpiece 40 and the fastening member 50, thereby joining the bottom inner surface 41a of the bottom wall 41 of the workpiece 40 and the fastening member 50 to each other.

[0098] This allows the fastening member 50 to be joined to the bottom inner surface 41a of the bottom wall 41 of the workpiece 40 by the first electrode 10 and the second electrode 20.

[0099] In summary, a resistance welding apparatus 1 capable of joining fastening members 50 to the bottom wall 41 and first side wall 46 of the workpiece 40 can be provided.

[0100] In particular, this can be achieved with a single resistance welding machine 1.

[0101] The adapter 30 is U-shaped, C-shaped, V-shaped, or U-shaped, opening to the front side Xa in the front-rear direction X. A suitable shape for the adapter 30 can be achieved.

[0102] The adapter 30 is movable in the vertical direction Z. The position of the adapter 30 can be finely adjusted in the vertical direction Z.

[0103] The coil spring 7 (biasing part) biases the adapter 30 with an elastic force I (biasing force) toward the upper side Zb, which is the side of the upper electrode 20 in the vertical direction Z. In the first mode M1, the upper electrode 20 presses the second extension 37 of the adapter 30 against the lower side Za, which is the side of the lower electrode 10 in the vertical direction Z, by a pressing force J. In the first mode M1, the upper electrode 20 moves the adapter 30 to the lower side Za (which is the side of the lower electrode 10 in the vertical direction Z) against the elastic force I (biasing force) of the coil spring 7 toward the upper side Zb (which is the side of the upper electrode 20 in the vertical direction Z). This makes it easier to adjust the position of the adapter 30 in the vertical direction Z. It also makes it easier to bring the adapter 30 into contact with the lower electrode 10 and / or the upper electrode 20.

[0104] The presence of the protrusion 38 makes it easier to bring the adapter 30 and the lower electrode 10 into contact.

[0105] Since the lower electrode 10 and the upper electrode 20 are aligned in the vertical direction Z, the layout of the lower electrode 10 and the upper electrode 20 in the resistance welding apparatus 1 becomes easier.

[0106] Figure 11 shows a resistance welding apparatus 1' according to a comparative example. In the resistance welding apparatus 1', the lower electrode 10' and the upper electrode 20' are positioned offset from each other in the front-rear direction X. The lower electrode 10' is located in front of the upper electrode 20' by Xa. A straight adapter 30' is fixed to the upper electrode 20'. The straight adapter 30' extends straight from the upper electrode 20' to the front by Xa. In the resistance welding apparatus 1', since the lower electrode 10' and the upper electrode 20 are offset in the front-rear direction X, a moment M' is applied when pressure is applied. In the resistance welding apparatus 1', the first actuator 4' for moving the upper electrode 20' is subjected to a load and damaged by this moment M'.

[0107] In the resistance welding apparatus 1 according to this embodiment, the lower electrode 10 and the upper electrode 20 are not offset and are in the same position in the front-rear direction X, so the moment M' generated in the resistance welding apparatus 1' according to the comparative example can be suppressed. In the resistance welding apparatus 1 according to this embodiment, the first actuator 4 for moving the upper electrode 20 can be prevented from being damaged by the load.

[0108] <Second Embodiment> A second embodiment will now be described. In the following description, components similar to those in the above embodiment will be denoted by the same reference numerals, and detailed descriptions will be omitted. Figure 10 shows a resistance welding apparatus 1.

[0109] The second outer surface 37b of the second extension 37 of the adapter 30 is provided with a protrusion 38 that projects upward Zb. The adapter 30 has a fixed guide pin 38a. The fixed guide pin 38a is provided on the protrusion 38 of the second outer surface 37b of the second extension 37 of the adapter 30. The fixed guide pin 38a extends upward Zb from the upper surface of the protrusion 38.

[0110] The resistance welding method is performed in third mode M3. In third mode M3, the adapter 30 is in the first position P1.

[0111] In the third mode M3, the workpiece 40 is positioned with its rear Xb (the side of the adapter 30) open in the front-rear direction X. In the third mode M3, the first side wall 46 of the workpiece 40 is positioned on the lower side Za, and the second side wall 47 of the workpiece 40 is positioned on the upper side Zb.

[0112] In the third mode M3, the first outer surface 36b of the first extension 36 of the adapter 30 is positioned on the upper end 11 of the lower electrode 10. The first outer surface 36b of the first extension 36 of the adapter 30 is in contact with the lower electrode 10.

[0113] In the third mode M3, a hole 48 drilled in the second side wall 47 of the workpiece 40 is passed through a fixed guide pin 38a that protrudes upward Zb from a protrusion 38 on the second outer surface 37b of the second extension 37 of the adapter 30. In the third mode M3, the through hole 53 of the fastening member 50 is hooked onto the fixed guide pin 38a from upward Zb. At this time, the main body portion 51 of the fastening member 50 is located upward Zb and the projection 52 is located downward Za. The fastening member 50 is located upward Zb above the second outer surface 47b of the second side wall 47 of the workpiece 40. The projection 52 of the fastening member 50 contacts the second outer surface 47b of the second side wall 47 of the workpiece 40. The upper end of the fixed guide pin 38a may be located upward Zb above the upper surface of the main body portion 51 of the fastening member 50.

[0114] In the third mode M3, the upper electrode 20 is moved to the lower side Za, bringing it closer to the lower electrode 10. The lower end 21 of the upper electrode 20 contacts the upper end of the fixing guide pin 38a, which protrudes above Zb above the upper surface of the main body 51 of the fastening member 50.

[0115] Here, the upper electrode 20 has a housing hole for accommodating the fixed guide pin 38a. When the upper electrode 20 moves to the lower side Za, the upper end of the fixed guide pin 38a is accommodated in the housing hole of the upper electrode 20. In the third mode M3, the lower end 21 of the upper electrode 20 contacts the upper surface of the main body 51 of the fastening member 50.

[0116] In the third mode M3, the second side wall 47 of the workpiece 40 and the fastening member 50 are pressurized by the lower electrode 10 and the upper electrode 20 via the adapter 30.

[0117] In the third mode M3, current is supplied between the lower electrode 10 and the upper electrode 20 via the first extension 36 of the adapter 30, the base portion 31 of the adapter 30, the second extension 37 of the adapter 30, the second side wall 47 of the workpiece 40, and the fastening member 50.

[0118] In the third mode M3, the second outer surface 47b of the second side wall 47 of the workpiece 40 and the fastening member 50 are resistance welded to each other.

[0119] In summary, in the third mode M3, the second side wall 47 of the workpiece 40 and the fastening member 50 are resist-welded to each other by applying pressure with the lower electrode 10 and the upper electrode 20 via the adapter 30, while current is passed between the lower electrode 10 and the upper electrode 20 via the first extension 36 of the adapter 30, the base portion 31 of the adapter 30, the second extension 37 of the adapter 30, the second side wall 47 of the workpiece 40, and the fastening member 50.

[0120] <Other Embodiments> Although this disclosure has been described above with reference to preferred embodiments, this description is not limiting, and of course, various modifications, substitutions, or combinations are possible.

[0121] The biasing element (elastic member) is not limited to a coil spring; for example, it may be a leaf spring, a disc spring, rubber, or a piston cylinder mechanism.

[0122] The first guide 39a and the second guide 39b do not have to be separate components; for example, they may be integrally formed in a cylindrical shape.

[0123] The protrusion 38 may be provided on the second outer surface 37b, which is the surface of the second extension 37 on the side of the upper electrode 20 (see the dashed line in Figure 1). The protrusion 38 may be provided on at least one (one or both) of the first outer surface 36b, which is the surface of the first extension 36 on the side of the lower electrode 10, and the second outer surface 37b, which is the surface of the second extension 37 on the side of the upper electrode 20. Furthermore, the protrusion 38 may be omitted.

[0124] In the adapter 30, the first extension 36 may extend from the portion above (inward) the lower end 31a of the base portion 31 toward the front Xa. Similarly, in the adapter 30, the second extension 37 may extend from the portion below (inward) the upper end 31b of the base portion 31 toward the front Xa. The first extension 36 and the second extension 37 may extend diagonally with respect to the front-rear direction X. The base portion 31 may extend diagonally with respect to the up-down direction Z. The same applies to the workpiece 40.

[0125] The fastening member 50 is not limited to a square nut; for example, it may be a polygonal nut other than a square, or a circular nut. Furthermore, the fastening member 50 may be something other than a nut, such as a washer or a sleeve. Even more, the fastening member 50 may be something like a bolt or a rivet. The fastening member 50 may also be any other type of component.

[0126] The lower electrode 10 may be movable.

[0127] Guide pin 5 is optional.

[0128] The first and second directions do not have to be orthogonal to each other, but may intersect each other at an angle. The first direction may extend at an angle to the vertical direction. The second direction may extend at an angle to the horizontal direction. The first direction may be horizontal and the second direction may be vertical. In this case, it is advisable to support the workpiece 40 and the fastening member 50 separately to prevent them from falling off.

[0129] This disclosure is extremely useful and highly industrially applicable because it can be applied to resistance welding apparatus and resistance welding methods.

[0130] Z: Up / Down direction (first direction) Za: Lower side Zb: Upper side X: Front / back direction (second direction) Xa: Front side (one side) Xb: Rear side (other side) Y: Left / right direction T: Thickness direction E: Vertical direction F: Horizontal direction Fa: One end Fb: Other end P1: First position P2: Second position M1: First mode M2: Second mode M3: Third mode I: Elastic force (biasing force) J: Pressing force 1: Resistance welding device 2: Lower holder 3: Upper holder 4: First actuator 5: Guide pin 6: Second actuator 6a: Rod 6b: Drive mechanism 7: Coil spring (biasing part, elastic member) 10: Lower electrode (first electrode) 11: Upper end 20: Upper electrode (second electrode) 21: Lower end 30: Adapter 31: Base part 31a: Lower end 31b: Upper end 36 First extension 36a First inner surface 36b First outer surface 37 Second extension 37a Second inner surface 37b Second outer surface 38 Protrusion 38a Fixing guide pin 39a First guide 39b Second guide 39c Pin 40 Workpiece 41 Bottom wall 41a Bottom inner surface 41b Bottom outer surface 46 First side wall 46a First side inner surface 46b First side outer surface 47 Second side wall 47a Second side inner surface 47b Second side outer surface 48 Hole 50 Fastening member 51 Main body 52 Projection 53 Through hole 1' Resistance welding device 10' Lower electrode 20' Upper electrode 30' Straight adapter M' Moment

Claims

1. A resistance welding apparatus comprising: a first electrode; a second electrode that moves toward or away from the first electrode in a first direction; and a conductive adapter that moves in a second direction intersecting the first direction, wherein the adapter enters a first position between the first electrode and the second electrode by moving to one side in the second direction, and retreats to a second position away from the first position by moving to the other side in the second direction, and the adapter includes: a base portion extending in the first direction; a first extension portion of the base portion extending from the side of the first electrode in the first direction to the one side in the second direction; and a second extension portion of the base portion extending from the side of the second electrode in the first direction to the one side in the second direction.

2. The resistance welding apparatus according to claim 1, wherein the adapter is U-shaped, C-shaped, V-shaped, or U-shaped, opening to one side in the second direction.

3. The resistance welding apparatus according to claim 1, wherein a protrusion is provided on at least one of the first outer surface, which is the surface of the first extension facing the first electrode, and the second outer surface, which is the surface of the second extension facing the second electrode.

4. The resistance welding apparatus according to claim 1, wherein the adapter is movable in the first direction.

5. The resistance welding apparatus according to claim 1, wherein the first direction is the vertical direction, the first electrode is positioned below the second electrode, and the second electrode is positioned above the first electrode.

6. A resistance welding method for resistance welding a workpiece and a fastening member using a resistance welding apparatus according to any one of claims 1 to 5, wherein the workpiece includes a bottom wall, a first side wall erected on the bottom wall, and a second side wall erected on the bottom wall at a position separate from the first side wall, the resistance welding method performs a first mode in which the adapter is in the first position, in which the workpiece is positioned open to the adapter in the second direction, the first side wall of the workpiece is positioned on the side of the first electrode and the second side wall of the workpiece is positioned on the side of the second electrode, and the first side wall of the workpiece and the fastening member are resist welded to each other by applying pressure to the first side wall of the workpiece and the fastening member with the first electrode and the second electrode via the adapter, and by passing current between the first electrode and the second electrode via the first side wall of the workpiece, the fastening member, the first extension of the adapter and the second extension of the adapter.

7. The resistance welding method according to claim 6, wherein the adapter is in the second position, and in the second mode, the workpiece is positioned facing the second electrode in the first direction, and the bottom wall of the workpiece and the fastening member are pressed together by the first electrode and the second electrode, and current is passed between the first electrode and the second electrode through the bottom wall of the workpiece and the fastening member to join the bottom inner surface of the bottom wall of the workpiece and the fastening member to each other.

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