JP7283298B2 - Indirect spot welding method, welding equipment and vehicle - Google Patents

Description

The present disclosure relates to an indirect spot welding method, a welding device, and a vehicle.

Conventionally, indirect spot welding has been performed when another member is arranged on one side of a member to be welded, or when there is a space constraint (see Patent Document 1, for example).

In Patent Document 1, in indirect spot welding, a clamping member for clamping a plate-shaped member to be welded between the ground electrode is provided to ensure sufficient contact between the ground electrode and the plate-shaped member. Techniques for suppressing welding and electrolytic corrosion in the vicinity of the contact portion between the electrode and the plate-shaped member have been disclosed.

JP 2016-59937 A

In the technique disclosed in Patent Document 1, as shown in FIG. 1 of Patent Document 1, the ground electrode and the sandwiching member are integrated into a C-shaped member, while the welding electrode is integrated with the C-shaped member. is configured as a separate member. As a result, the distance between the ground electrode and the welding electrode becomes longer, which increases the size of the equipment, making it difficult to perform welding in a narrow space. There was a problem that it was difficult to make

Therefore, the inventors of the present application have found an indirect spot welding apparatus and welding method that can contribute to the size reduction of the apparatus and improve the efficiency of welding work by integrating the welding electrode and the ground electrode, and filed an application for the same. (Japanese Patent Application 2018-181295).

By the way, when indirect spot welding is performed, a clamping trace may remain at the clamping point between the ground electrode and the clamping member. The portion where the clamping marks are formed tends to cause progress of corrosion due to reasons such as roughening of the plating on the surface. That is, the workpieces joined by spot welding tend to decrease in plate thickness from the inner side between the plates at the portions where the plates between adjacent welding points are vacant. However, since the pinching point is likely to cause corrosion from the outside in addition to the thickness reduction from the inside between the plates, it is not possible to set the pinching point at a portion that is exposed to the external environment, for example. Then, while it is desirable to set welding points by indirect spot welding at predetermined intervals, there are cases where it is not possible to similarly set clamping points at predetermined intervals.

An object of the present disclosure is to provide an indirect spot welding method, a welding apparatus, and a vehicle that enable welding at a desired position even when the space for setting a clamping point is limited.

In order to solve the above problems, an indirect spot welding method according to a first technique disclosed herein provides a structure having a first member and a second member joined to the first member. A method of indirect spot welding a third member to an outer surface, wherein the first member includes a first body portion extending in a predetermined direction, and a first body portion connected to an end of the first body portion and extending in the predetermined direction. a first flange portion extending in the predetermined direction, the second member including a second body portion extending in the predetermined direction; a second flange portion connected to an end of the second body portion and extending in the predetermined direction; wherein the structure includes: a flange joint portion formed by the first flange portion and the second flange portion joined together; a body portion formed by the first body portion and the second body portion; wherein the third member is welded to the outer surface of the first member forming the body portion of the structure at a plurality of welding points aligned in the predetermined direction, and the flange joint portion between the columnar first electrode arranged on the first flange portion side and the second electrode arranged coaxially opposite the first electrode on the second flange portion side of the flange joint portion; a sandwiching step of sandwiching the sandwiching point in the main body portion of the structure, and in a state in which the third member is in contact with the outer surface of the first member in the main body portion of the structure, the welding point on the outer surface of the third member a pressurizing contact step of pressurizing and contacting a third electrode; and in a state in which the second electrode is insulated from the first electrode and the third electrode and the first electrode or the third electrode is grounded, the and an energizing step of energizing between the first electrode and the third electrode, and adjusting the position of the welding point with respect to the clamping point by rotating the third electrode in the circumferential direction of the axis of the first electrode. It is characterized by being possible.

According to this configuration, since the position of the welding point with respect to the clamping point can be adjusted, even if the space for setting the clamping point is limited, the distance between adjacent welding points can be adjusted regardless of the position of the clamping point. can be adjusted.

A second technique is the first technique, wherein the flange joint portion includes a covered portion covered by an exterior member and an exposed portion not covered by the exterior member, and the clamping point is provided in the covered portion. is provided, but is not provided in the exposed portion.

Since the clamping point is a portion where the first electrode and the second electrode are in pressure contact, there is a tendency that the plating on the surface of the first member and the second member is peeled off and easily corroded. Since the exposed portion is exposed to the external environment, if a clamping point is arranged in the exposed portion, corrosion tends to progress from the clamping point. On the other hand, since the covered portion is covered with the exterior member, it is not directly exposed to the external environment. In this case, even if the pinching point is arranged in the covering portion, corrosion does not easily progress from the pinching point. Therefore, with this configuration, the durability of the structure can be improved. In addition, since the flange portion of the exposed portion can be visually recognized from the outside, it is possible to improve the design of the structure by not providing a clamping point.

A third technique is the first or second technique, wherein the first member and the second member are spot-welded at a plurality of flange welding points in the predetermined direction at the flange joint, and The clamping point is characterized in that it is arranged at a position different from the flange welding point.

Since the flange welding point is already spot-welded, if the clamping point is set at the same place as the flange welding point, it is difficult for the first electrode and the second electrode to come into contact with each other, and it is difficult to secure a sufficient contact area. . In this case, since it is difficult to secure a sufficient amount of current at the time of energization, indirect spot welding at the welding point may not proceed sufficiently, and sufficient joint strength may not be obtained. According to this configuration, by arranging the clamping point at a position different from the flange welding point, a sufficient contact area between the first and second electrodes and the first and second members can be ensured. Thus, sufficient joint strength can be ensured at the welding points.

A fourth technique is, in any one of the first to third techniques, by adjusting the position of the third electrode in the circumferential direction and the radial direction with respect to the axis of the first electrode, thereby adjusting the welding point to the It is characterized in that they are formed at regular intervals in a predetermined direction.

According to this configuration, the third electrode can move not only in the circumferential direction around the axis of the first electrode, but also in the radial direction, so that welding points can be formed at regular intervals. Thus, the joint strength between the first member and the third member can be improved.

A fifth technique is that in any one of the first to fourth techniques, the main body portion of the structure is formed in the predetermined direction formed by the inner side surfaces of the first main body portion and the second main body portion. It is characterized by having an extending hollow portion.

According to this configuration, the third member can be welded with high bonding strength even to a structure having a hollow portion.

A sixth technique is any one of the first to fifth techniques, wherein the first member and the second member are a side sill inner and a side sill inner, respectively, and the third member is a cab side outer. It is characterized by

According to this configuration, it is possible to provide a vehicle having a side sill structure excellent in durability, strength and design.

An indirect spot welding apparatus according to a seventh technique disclosed herein is a structure having a first member and a second member joined to the first member. An apparatus for indirect spot welding, wherein the first member includes a first body portion extending in a predetermined direction, a first flange portion connected to an end of the first body portion and extending in the predetermined direction; wherein the second member has a second body portion extending in the predetermined direction and a second flange portion connected to an end of the second body portion and extending in the predetermined direction; comprises a flange joint portion composed of the first flange portion and the second flange portion joined to each other, and a body portion formed by the first body portion and the second body portion, and the third member is welded to the outer surface of the first member forming the body portion of the structure at a plurality of welding points aligned in the predetermined direction, and is arranged on the first flange portion side of the flange joint portion and a columnar first electrode that is physically integrated with the first electrode and is coaxial with the first electrode so as to sandwich the sandwiching point at the flange joint between the first electrode and the first electrode. a second electrode disposed oppositely; and a third electrode physically integrated with the first electrode and brought into pressure contact with the welding point on the outer surface of the third member, wherein the second electrode is insulated from the first electrode and the third electrode, the first electrode or the third electrode is grounded, and the third electrode rotates in the circumferential direction about the axis of the first electrode. It is possible to adjust the position of the welding point with respect to the clamping point by rotating the third electrode in the circumferential direction about the axis of the first electrode.

According to this configuration, since the position of the welding point with respect to the clamping point can be adjusted, even if the space for setting the clamping point is limited, the distance between adjacent welding points can be adjusted regardless of the position of the clamping point. can be adjusted. In addition, since the second electrode and the third electrode are physically integrated with the first electrode, indirect spot welding can be effectively performed even when the distance between the clamping point and the welding point is small. can be done.

An eighth technique is the seventh technique, wherein the third electrode is movable in the radial direction of the axis of the first electrode, and the third electrode is movable in the circumferential direction and the axis of the first electrode. By adjusting the position in the radial direction, the welding points are formed at regular intervals in the predetermined direction.

According to this configuration, the third electrode can move not only in the circumferential direction around the axis of the first electrode, but also in the radial direction, so that welding points can be formed at regular intervals. Thus, the joint strength between the first member and the third member can be improved.

A ninth technique is the seventh or eighth technique, wherein the body portion of the structure includes a hollow portion extending in the predetermined direction and formed by inner side surfaces of the first body portion and the second body portion. It is characterized by having

According to this configuration, the third member can be welded with high bonding strength even to a structure having a hollow portion.

A vehicle according to a tenth technique disclosed herein includes a side sill lane that extends in the front-rear direction and has first flange portions at both ends in the vertical direction, and a flange joint portion that extends in the front-rear direction and is joined to the first flange portion. a side sill inner forming a hollow portion extending in the front-rear direction while being joined to the side sill rain; and a cab joined to the outer surface of the hollow portion of the side sill rain. A vehicle comprising a side outer and an exterior member arranged on the same side as the cab side outer with respect to the side sill rain and covering a part of the flange joint and not covering the other part, The first flange portion and the second flange portion are spot-welded at a plurality of flange welding points arranged in the front-rear direction, and the part of the flange joint portion is indirect spot-welded with the flange welding points. and the other portion of the flange joint includes the flange welding point and does not include the pinching point.

According to this configuration, it is possible to obtain a vehicle having a side sill structure excellent in durability, strength and design.

As described above, according to the present disclosure, since the position of the welding point with respect to the clamping point can be adjusted, even if the space for setting the clamping point is limited, regardless of the position of the clamping point. You can adjust the spacing between adjacent weld points.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the indirect spot welding apparatus which concerns on one Embodiment. 2 is a diagram showing a circuit configuration of the indirect spot welding device of FIG. 1; FIG. FIG. 2 is a plan view of a first electrode, a third electrode, and a connecting portion of the indirect spot welding apparatus of FIG. 1; It is a perspective view showing an example of vehicles concerning this embodiment. FIG. 5 is a bottom view of the side sill structure portion of FIG. 4; FIG. 6 is a cross-sectional view taken along line AA of FIG. 5; FIG. 6 is a cross-sectional view taken along line BB of FIG. 5; FIG. 6 is a cross-sectional view taken along line CC of FIG. 5; FIG. 5 is a right side view of the side sill structure portion of FIG. 4; FIG. 10 is a perspective view of the right side view of FIG. 9 as seen slightly from below; FIG. 10 is a diagram of the state in which the side step is removed in FIG. 9; 4 is a flowchart for explaining steps of a spot welding method according to one embodiment; It is a figure which shows typically the state which pressure-contacted the 3rd electrode with the workpiece|work which concerns on other embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. The following description of preferred embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its applicability or its uses.

(one embodiment)
<Spot welding equipment>
As shown in FIGS. 1 to 3, the indirect spot welding device 1 according to Embodiment 1 includes a first electrode 11, a second electrode 12, and a third electrode 13. As shown in FIGS. A workpiece 100 is arranged between the first electrode 11 and the third electrode 13 and the second electrode 12 .

≪Work and vehicle≫
As shown in FIGS. 4 to 11, the workpiece 100 is a part of the side sill structure of the vehicle 900 according to this embodiment.

FIG. 4 is a perspective view showing the rear lower structure of the vehicle 900 according to this embodiment. In addition, in FIG. 4, illustration of a detailed configuration such as a tire is omitted. 5 is a bottom view of the side sill structure portion of FIG. 4. FIG. 6 to 8 are cross-sectional views taken along lines AA, BB and CC of FIG. 5, respectively. 9 is a right side view of the side sill structure portion of FIG. 4. FIG. 10 is a perspective view of the right side view of FIG. 9 as seen slightly from below. FIG. 11 is a view of FIG. 9 with the side step removed.

In this specification, when describing the vehicle 900 and its components, the front-rear direction, the left-right direction, and the up-down direction of the vehicle 900 are used as references, as shown in FIG. 4 . The front-rear direction, the left-right direction, and the up-down direction of the vehicle 900 are directions perpendicular to each other.

As shown in FIG. 6, the workpiece 100 includes a side sill inner 110 (first member), a side sill inner 120 (second member), and a cab side outer 130 (third member). Further outside the workpiece 100, a side step 160 (exterior member) is provided.

－Side sill rain－
The side sill rain 110 is a member extending in the front-rear direction (predetermined direction). The side sill lane 110 has a first body portion 111 and a first flange portion 112 .

The first main body portion 111 is a half-pipe-shaped portion that has a U-shaped cross section that is convex to the right and extends in the front-rear direction. The first flange portions 112 are plate portions that are connected to both ends in the vertical direction of the first body portion 111 and extend in the front-rear direction.

-Side sill inner-
Side sill inner 120 is a member extending in the front-rear direction, similar to side sill rain 110 . The side sill inner 120 has a second body portion 121 and a second flange portion 122 . The second body portion 121 is a half-pipe-shaped portion that has a U-shaped cross section that is convex to the left and extends in the front-rear direction. The second flange portions 122 are plate portions that are connected to both ends in the vertical direction of the second body portion 121 and extend in the front-rear direction.

-Structure-
The side sill inner 110 and the side sill inner 120 form a pipe-shaped structure 140 extending in the longitudinal direction by joining the first flange portion 112 and the second flange portion 122 to each other. Structure 140 is a component that forms the frame of the lateral lower portion of vehicle 900 . Specifically, for example, as shown in FIG. 11, the first flange portion 112 and the second flange portion 122 are spot-welded at a plurality of flange welding points 145 arranged in the front-rear direction. The first flange portion 112 and the second flange portion 122 thus form a flange joint 142 of the structure 140 . With the first flange portion 112 and the second flange portion 122 joined together, the first body portion 111 and the second body portion 121 form the body portion 141 of the structure 140 as shown in FIGS. be.

The main body portion 141 includes a hollow portion 143 formed by inner surfaces of the first main body portion 111 and the second main body portion 121 and extending in the front-rear direction. That is, the structure 140 becomes a member having a closed cross-sectional structure with a hollow portion 143 by forming the flange joint portion 142 .

-Cab Side Outer-
Cab side outer 130 is a side exterior member of vehicle 900 . The cab side outer 130 is joined to the outer surface of the first main body portion 111 of the side sill lane 110 .

The cab side outer 130 has a plate-shaped third flange portion 131 extending in the front-rear direction. The third flange portion 131 is spot-welded to the outer surface of the first main body portion 111 of the side sill lane 110 at a plurality of welding points 149 aligned in the front-rear direction.

-side step-
A side step 160 is arranged on the side sill lane 110 side of the workpiece 100 so as to protect the cab side outer 130 and the flange joint portion 142 . The side step 160 covers the side sill structure of the vehicle 900 and contributes to improving the design of the vehicle 900, suppressing damage to the side sill structure, and the like.

As shown in FIGS. 4, 5 and 7, the side step 160 has a mounting portion 162. As shown in FIG. A bolt hole 163 is provided in the mounting portion 162 . The side step 160 is fixed to the side sill lane 110 with a bolt (not shown) inserted into the bolt hole 163 .

As shown in FIGS. 4 and 5, the side step 160 has a recess 161 for attaching a jack (not shown) when the vehicle 900 is jacked up. As shown in FIGS. 4, 6 to 8, etc., the portion of the side step 160 other than the concave portion 161 covers the flange joint portion 142. As shown in FIG. On the other hand, the portion of the side step 160 where the concave portion 161 is arranged exposes the flange joint portion 142 . That is, the flange joint portion 142 of the structure 140 includes a covered portion 142A (part) covered with the side step 160 and an exposed portion 142B (other portion) not covered with the side step 160. As shown in FIG.

<<Equipment configuration>>
An indirect spot welding apparatus 1 according to this embodiment is an apparatus for indirect spot welding a cab side outer 130 to the outer surface of a side sill lane 110 .

- Electric circuit and power supply -
The indirect spot welding device 1 includes an electric circuit 16 and a power supply device 15 electrically connected to the first electrode 11 and the third electrode 13, as shown in FIG. The power supply device 15 includes, although not shown, a control section that controls the amount of current flowing between the electrodes.

- First electrode and second electrode -
The first electrode 11 and the second electrode 12 are pressed into contact with the flange joint 142 . A flange joint 142 is sandwiched between the first electrode 11 and the second electrode 12 .

As shown in FIGS. 1 and 2, the first electrode 11 is a cylindrical earth electrode that is arranged on the first flange portion 112 side of the flange joint portion 142 and grounded. The second electrode 12 is a cylindrical counter electrode arranged on the second flange portion 122 side of the flange joint portion 142 and insulated from the first electrode 11 and the third electrode 13 . The shape of the first electrode 11 and the second electrode 12 is not limited to a columnar shape, and may be a columnar shape such as an elliptical columnar shape or a polygonal columnar shape.

As shown in FIG. 1, the second electrode 12 is physically integrated with the first electrode 11 to form a C-type gun. Specifically, as shown in FIG. 1, the second electrode 12 is connected to the base 2a. The base 2a is connected to the support portion 2c. A cylindrical first electrode gun 11b is connected to the tip of the support portion 2c. The first electrode 11 is connected to the tip of the first electrode gun 11b. That is, the first electrode 11 and the second electrode 12 form a C-type gun together with the base 2a, the support portion 2c, and the first electrode gun 11b.

The central axis of the first electrode gun 11b and the first electrode 11 is the axis L1. The second electrode 12 is coaxially arranged to face the first electrode 11 . That is, the first electrode 11 and the second electrode 12 have the same axial center L1.

A first electrode driving means 2b is provided on the opposite side of the first electrode gun 11b to the side to which the first electrode 11 is connected.

The first electrode gun 11b moves in the direction of the axis L1 as indicated by the arrow G1 in FIG. 1 in accordance with the operation of the first electrode driving means 2b. As the first electrode gun 11b moves, the first electrode 11 also moves in the axial center L1 direction. That is, the first electrode 11 moves closer to the second electrode 12 as the first electrode driving means 2b operates. Thus, the first electrode 11 is press-contacted to the clamping point 147 on the outer surface of the first flange portion 112 of the flange joint portion 142 . On the other hand, the second electrode 12 is pressure-contacted to the clamping point 147 on the outer surface of the second flange portion 122 of the flange joint portion 142 . Thus, the second electrode 12 and the first electrode 11 sandwich the sandwiching point 147 in the flange joint portion 142 .

Although the first electrode drive means 2b is not particularly limited, for example, a drive mechanism using an air cylinder, a ball screw mechanism driven by a motor, a robot arm, or the like can be adopted.

The first electrode 11 is in pressure contact with the side sill lane 110 at the first electrode distal end surface 11a. The shape of the first electrode tip surface 11a is a circle centered on the axis L1 (see FIG. 3), but is not limited to this shape as long as a sufficient amount of energization can be secured. A shape such as an ellipse or a rectangle centered on the axis L1 may be used. The maximum diameter of the first electrode tip surface 11a can be, for example, 5 mm or more and 16 mm or less from the viewpoint of ensuring a sufficient amount of electricity.

Also, the second electrode 12 contacts the side sill inner 120 at the second electrode distal end surface 12a. The shape of the second electrode tip surface 12a is not particularly limited, either. It can be circular, elliptical, rectangular, etc., having a The maximum diameter of the second electrode tip surface 12a can be, for example, 3 mm or more and 8 mm or less from the viewpoint of securely holding the flange joint portion 142 between the first electrode 11 and the first electrode 11 . The maximum diameter of the second electrode tip surface 12a is preferably smaller than the maximum diameter of the first electrode tip surface 11a. As a result, it is possible to suppress slippage when the flange joint portion 142 is sandwiched between the first electrode tip surface 11a and the second electrode tip surface 12a.

As shown in FIG. 2, the second electrode 12 is not electrically connected to the first electrode 11 and the third electrode 13 and is insulated from both electrodes. Specifically, the second electrode 12 and/or the base 2a to which the second electrode 12 is connected is formed or covered with an insulating material such as rubber or baking. As a result, the electric path during energization can be restricted between the two electrodes of the first electrode 11 and the third electrode 13, and efficient welding becomes possible.

The pressing force of the first electrode 11 is, for example, 1.5 kN or more and 6 kN or less from the viewpoint of ensuring sufficient contact with the side sill rain 110 and securely holding the flange joint portion 142 between the second electrode 12 and the second electrode 12. be able to.

-Third electrode-
The third electrode 13 is a cylindrical welding electrode. The third electrode 13 is pressed into contact with a welding point 149 on the outer surface of the cabside outer 130 . The shape of the third electrode 13 is not limited to a columnar shape, and may be a columnar shape such as an elliptical columnar shape or a polygonal columnar shape.

A third electrode 13 is connected to the first electrode 11 and further physically integrated into the C-type gun consisting of the first electrode 11 and the second electrode 12 .

Specifically, a columnar third electrode gun 13b is provided on the first electrode gun 11b via the connecting portion 4 . The cylindrical third electrode 13 is provided at the tip of the third electrode gun 13b. The central axis of the third electrode 13 and the third electrode gun 13b is the axis L2. The axis L2 is parallel to the axis L1 of the first electrode 11 and the first electrode gun 11b, and is at a position shifted from the axis L1.

Since the third electrode 13 is physically integrated with the first electrode 11, the position of the third electrode 13 relative to the first electrode 11 in the axial center L2 direction can be maintained with high accuracy. Then, the pressing force of the third electrode 13 can be controlled with high accuracy. In addition, since the third electrode 13 can be pressurized independently of the first electrode 11, the third electrode 13 can be accurately pressurized and brought into contact with the cabside outer 130 with a lower pressurizing force than the first electrode 11. . Thus, the contact resistance of the third electrode 13 can be stably controlled while suppressing the deformation of the side sill inner 110 and the side sill inner 120, and excellent welding quality can be achieved with good reproducibility.

The third electrode driving means 3 is provided in the third electrode gun 13b. The third electrode driving means 3 allows the third electrode gun 13b to move in the direction of the axis L2 as indicated by the arrow G2 in FIG. Movement of the third electrode gun 13b is independent of movement of the first electrode gun 11b. That is, the third electrode 13 is configured to be movable in the direction of the axis L2 independently of the movement of the first electrode 11 in the direction of the axis L1. As the third electrode drive means 3, for example, a drive mechanism using an air cylinder, a ball screw mechanism driven by a motor, or the like can be employed.

By physically integrating the third electrode gun 13b with the first electrode gun 11b, the inter-electrode distance between the first electrode 11 and the third electrode 13 can be shortened. Specifically, the distance between the center of the first electrode tip surface 11a and the center of the third electrode tip surface 13a, i.e., the shortest distance between the axis L1 and the axis L2, shortens the electric circuit, thereby reducing the amount of energization and the welding time. From the viewpoint of allowing efficient welding by increasing the width, the thickness can be, for example, 30 mm or more and 150 mm or less. By adopting this configuration, the electric circuit can be shortened, and the energization time required for welding can be shortened. Thus, deformation of the workpiece 100 due to pressure contact between the third electrode 13, the first electrode 11, and the second electrode 12 can be suppressed. In addition, it is possible to suppress excessive welding or the like of the welding target portion due to the energization. Furthermore, it can result in cost reduction and simplification of the welding process.

As shown in FIG. 1, the third electrode 13 presses into contact with the cabside outer 130 at the third electrode tip surface 13a. The shape of the third electrode tip surface 13a is a circle centered on the axis L2 (see FIG. 3). The shape of the third electrode distal end surface 13a is not limited to the circular shape, as long as a sufficient amount of current can be secured. The maximum diameter of the third electrode tip surface 13a can be, for example, 3 mm or more and 16 mm or less from the viewpoint of narrowing down the electrical path while ensuring a sufficient amount of electricity.

Moreover, from the viewpoint of suppressing damage to the cab-side outer 130 while ensuring sufficient contact with the cab-side outer 130, the pressing force of the third electrode 13 can be, for example, 0.4 kN or more and 2.0 kN or less. In addition, it is desirable that the pressure applied to the third electrode 13 is smaller than the pressure applied to the first electrode 11 . By bringing the first electrode 11 into contact with the flange joint portion 142 with a high pressure force, the workpiece 100 can be reliably held between the first electrode 11 and the second electrode 12 . On the other hand, since the workpiece 100 is fixed by sandwiching the first electrode 11 and the second electrode 12, the third electrode 13 can reliably contact the workpiece 100 even with a low pressure. Thus, deformation of the workpiece 100 due to pressure contact and heat generation of the third electrode 13 can be suppressed. In addition, it is possible to suppress excessive welding or the like of the welding target part due to the energization, and it is possible to bring about excellent welding quality with good reproducibility.

In addition, in the indirect spot welding apparatus 1 according to the present embodiment, the third electrode 13 is rotatable in the circumferential direction of the axis L1 of the first electrode 11, as indicated by the arrow G3 in FIG. The third electrode 13 is also movable in the radial direction of the axis L1 of the first electrode 11, as indicated by the arrow G4 in FIG. The effects of these configurations will be described later.

<Spot welding method>
The indirect spot welding method according to this embodiment, as shown in FIG. 12, includes a clamping step S1, a pressure contact step S2, and an energizing step S3.

-Clamping process-
First, in the sandwiching step S1, the flange joint portion 142 is sandwiched between the first electrode 11 and the second electrode 12 .

Specifically, for example, in a state in which the first electrode 11 and the second electrode 12 are sufficiently spaced apart, the clamping point 147 at the flange joint portion 142 of the structure 140 is placed on the second electrode distal end surface 12a of the second electrode 12. to place Then, the first electrode 11 is moved in the direction of the axis L1 by the operation of the first electrode driving means 2b, and the first electrode tip surface 11a is brought into pressure contact with the clamping point 147 of the flange joint portion 142. As shown in FIG. Then, the clamping point 147 of the flange joint 142 is clamped by the first electrode 11 and the second electrode 12 .

- Pressure contact process -
Next, in the pressure contact step S2, the third flange portion 131 of the cab side outer 130 is brought into contact with the outer surface of the first main body portion 111 of the side sill lane 110 of the structure 140 . Then, the third electrode driving means 3 is driven to move the third electrode 13 in the direction of the axis L2, and the third electrode 13 is pressed into contact with the welding point 149 in the third flange portion 131 of the cab side outer 130. .

- Energization process -
Then, in the energizing step S3, by passing a current between the first electrode 11 and the third electrode 13, the cab side outer 130, the cab side outer 130, and the side sill rain 110 from the third electrode distal end surface 13a of the third electrode 13. An electric path C1 is formed that reaches the first electrode tip surface 11a of the first electrode 11 through the contact point, that is, the welding point 149 and the side sill lane 110 . Spot welding at the welding point 149 is then performed. The controller of the power supply device 15 adjusts the appropriate amount of current and welding time while maintaining the appropriate pressure applied to the third electrode 13 , and completes the welding of the cab side outer 130 and the side sill lane 110 .

-Characteristics and effects-
The indirect spot welding apparatus 1 according to this embodiment is characterized in that the third electrode 13 can be rotated in the circumferential direction of the axis L1 of the first electrode 11, as shown in FIG. In the spot welding method according to the present embodiment, by rotating the third electrode 13 in the circumferential direction of the axis L1 of the first electrode 11, the position of the welding point 149 with respect to the clamping point 147 can be adjusted. Characterized by

Corresponding pinch points 147 and weld points 149 are shown in dashed lines in FIG. That is, for example, when the first electrode 11 and the second electrode 12 clamp the clamping point 147A, the third electrode 13 is brought into contact with the welding point 149A to perform indirect spot welding.

Since the clamping point 147 is a portion where the first electrode 11 and the second electrode 12 are pressed against each other, the surface plating of the side sill lane 110 and the side sill inner 120 tends to peel off and corrode easily. Since the side sill rain 110 side of the exposed portion 142B of the flange joint portion 142 is not covered with the side step 160, it is exposed to the external environment. As a result, when the clamping point 147 is arranged in the exposed portion 142B, corrosion is likely to progress from the clamping point 147 . On the other hand, since the covering portion 142A of the flange joint portion 142 is covered with the side step 160, it is not directly exposed to the external environment. Then, even if the pinching point 147 is arranged on the covering portion 142A, the corrosion does not easily progress from the pinching point 147 . Therefore, the durability of the side sill structure of the vehicle 900 can be improved by forming the gripping point 147 on the covered portion 142A and not forming the gripping point 147 on the exposed portion 142B. In addition, as shown in FIG. 4, the exposed portion 142B can be visually recognized from the outside, and thus by not providing the clamping point 147, the design of the side sill structure can be improved.

Specifically, as shown in FIG. 11, for example, consider the case where the first electrode 11 and the second electrode 12 sandwich the sandwiching point 147A. In FIG. 11, it is assumed that welding is performed at welding points 149 in order from the front side. With the sandwiching point 147A sandwiched between the first electrode 11 and the second electrode 12, the third electrode 13 is brought into contact with the welding point 149A to perform welding at the welding point 149A. Thereafter, the clamping point 147A between the first electrode 11 and the second electrode 12 is released. Then, as shown in FIG. 3, the third electrode 13 is rotated in the circumferential direction of the axis L2 of the first electrode 11 . Then, the first electrode 11 and the second electrode 12 sandwich the pinching point 147A again, and the third electrode 13 is brought into contact with the welding point 149B to perform welding at the welding point 149B. Thus, by adjusting the position of the third electrode 13 in the circumferential direction with respect to the axis L1 of the first electrode 11, the interval between the adjacent welding points 149 can be adjusted without providing the clamping points 147 on the exposed portion 142B. be able to. Thus, the welding points 149 can be provided at certain intervals in the front-rear direction.

Further, the clamping point 147A between the first electrode 11 and the second electrode 12 is released, and the third electrode 13 is further rotated in the circumferential direction of the axis L2 of the first electrode 11. move away from Then, the first electrode 11 and the second electrode 12 hold the holding point 147A again, and the third electrode 13 is brought into contact with the welding point 149C to perform welding at the welding point 149C. By adjusting the position of the third electrode 13 in the circumferential direction and the radial direction with respect to the axis L1 of the first electrode 11 in this manner, the welding point 149 can be moved forward and backward without providing the clamping point 147 in the exposed portion 142B. It can be formed at almost regular intervals. When the welding points 149 are formed at substantially constant intervals, the bonding strength between the side sill lane 110 and the cab side outer 130 is made uniform in the region where the welding points 149 are formed in the longitudinal direction, thereby improving the bonding strength as a whole. can be done.

In addition, as shown in FIG. 11, the flange joint portion 142 has a flange welding point 145 when the first flange portion 112 and the second flange portion 122 are joined by spot welding. The sandwiching points 147 by the first electrode 11 and the second electrode 12 are desirably located at positions different from the flange welding points 145, for example, between adjacent flange welding points 145.

Since the flange welding point is already spot-welded, setting the clamping point 147 at the same location as the flange welding point 145 secures a sufficient contact area between the first electrode 11 and the first flange portion 112. can be difficult to do. If it does so, it will become difficult to ensure sufficient current amount in said energization process S3. As a result, the indirect spot welding at the welding point 149 may not proceed sufficiently, and sufficient joint strength may not be obtained. According to this configuration, a sufficient contact area between the first electrode 11 and the first flange portion 112 can be ensured by arranging the clamping point 147 at a position different from the flange welding point 145 . Thus, sufficient joint strength can be ensured at the welding points.

Therefore, as shown in FIG. 11, the vehicle 900 according to the present embodiment includes the flange welding point 145 and the pinching point 147 in the covered portion 142A, and the flange welding point 145 and the pinching point 147 in the exposed portion 142B. can be configured without Thus, a vehicle 900 having a side sill structure excellent in durability, strength and design can be obtained.

(Other embodiments)
Other embodiments according to the present disclosure will be described in detail below. In the description of these embodiments, the same parts as in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the above-described embodiment, the workpiece 100 has been described as an example of a part used for the side sill structure of the vehicle 900 . The indirect spot welding apparatus 1 and method according to the present embodiment can be used for spot welding not only the parts concerned but also other parts.

Specifically, both the first member and the second member may be plates. That is, the structure 140 has a structure in which two plates are laminated. The body portion 141 has a structure without the hollow portion 143 . In such a structure, for example, other members may be arranged on the side of the second member opposite to the side where the first member is arranged, that is, on the outer side of the second member. In such a case, since the third member cannot be directly spot-welded to the first member, the indirect spot welding apparatus 1 and method according to the present disclosure can be preferably applied.

Also, one of the first member and the second member may be a half-pipe type member as in the above embodiment, and the other may be a plate-like member.

Furthermore, the shape of the third member is not particularly limited as long as spot welding is possible at a plurality of welding points arranged in a predetermined direction on the outer surface of the first main body. The third member is, for example, a plate-like member, a member having a plate-like flange portion, or the like.

Specific examples of the first member, the second member, the third member, and the exterior member include the following. Specifically, the first member and the second member are, for example, vehicle parts that can be joined together, such as a front panel, a floor panel, a rear panel, a side sill, a tunnel rain, a cross member, a frame, and an outer panel. Further, the third member and the exterior member are parts such as an outer which are further joined to the vehicle part.

The first member, the second member, and the third member may be metal members that can be energized and generally spot-welded. Specifically, for example, iron, steel, aluminum, alloys thereof, and the like, and surface-plated metal members. The material of the exterior member is not particularly limited, and is appropriately determined according to the use of the exterior member.

In the above embodiment, the flange joint portion 142 was formed using spot welding, but the method of forming the flange joint portion 142 is not limited to spot welding. The flange joint 142 may be formed by various welding methods including spot welding, adhesives, rivets, or the like.

In the above embodiment, the case where the first electrode 11 is the ground electrode and the third electrode 13 is the welding electrode has been described as an example. .

As shown in FIG. 13, on the side of the third flange portion 131 of the cab side outer 130 at the welding point 149 facing the side sill lane 110, a convex portion 133 may be provided from the viewpoint of promoting welding in the energization step S3. good. The convex portion 133 is a protrusion that projects from the cab side outer 130 side toward the side sill lane 110 side at the welding point 149 . Due to the presence of the convex portion 133, the electric circuit C1 is restricted within the convex portion 133 when the cab side outer 130 is brought into contact with the side sill lane 110 and energized. Thus, nugget formation, which is the starting point of welding, is promoted, and efficient and rapid welding becomes possible.

The size of the protrusion 133 is not particularly limited, but from the viewpoint of promoting nugget formation and shortening the welding time, for example, the maximum diameter of the protrusion 133 can be 1 mm or more and 5 mm or less. The method of forming the convex portion 133 is not particularly limited, but it can be formed by press molding, punching, or the like. 13, the protrusion 133 is formed on the cab side outer 130, but may be formed on the side sill lane 110. As shown in FIG.

Further, instead of forming the convex portion 133, a configuration may be adopted in which a separate member such as a metal piece is arranged. Furthermore, as another method, the diameter of the third electrode tip surface 13a of the third electrode 13 may be minimized to increase the current density of the cabside outer 130 and the side sill lane 110 .

Furthermore, in the above embodiment, the configuration using a direct current has been described as an example, but an alternating current can also be used.

INDUSTRIAL APPLICABILITY The present disclosure is extremely useful because it can provide an indirect spot welding method, welding apparatus, and vehicle capable of welding at a desired location even when the space for setting the clamping point is limited.

1 indirect spot welding device 2a base 2b first electrode driving means 2c supporting portion 3 third electrode driving means 4 connecting portion 11 first electrode 11a first electrode tip surface 11b first electrode gun 12 second electrode 12a second Electrode tip surface 13 Third electrode 13a Third electrode tip surface 13b Third electrode gun 15 Power supply device 16 Electric circuit 100 Work 110 Side sill rain (first member)
111 First body portion 112 First flange portion 120 Side sill inner (second member)
121 second body portion 122 second flange portion 130 cab side outer (third member)
131 Third flange portion 133 Protruding portion 140 Structure 141 Body portion 142 Flange joint portion 142A Coating portion 142B Exposed portion 143 Hollow portion 145 Flange welding point 147 Clamping point 149 Welding point 160 Side step (exterior member)
C1 electric circuit L1 axial center L2 (of first electrode and first electrode gun) axial center S1 (third electrode and third electrode gun) clamping step S2 pressure contact step S3 energization step

Claims (10)

A method of indirect spot welding a third member to an outer surface of a structure comprising a first member and a second member joined to the first member, the method comprising:
The first member has a first body portion extending in a predetermined direction and a first flange portion connected to an end of the first body portion and extending in the predetermined direction,
The second member has a second body portion extending in the predetermined direction and a second flange portion connected to an end of the second body portion and extending in the predetermined direction,
The structure includes a flange joint portion formed by the first flange portion and the second flange portion joined to each other, and a body portion formed by the first body portion and the second body portion,
The third member is welded to the outer surface of the first member forming the body portion of the structure at a plurality of welding points aligned in the predetermined direction,
Between a columnar first electrode arranged on the first flange portion side of the flange joint portion and a second electrode arranged coaxially opposite the first electrode on the second flange portion side of the flange joint portion A pinching step of pinching the pinching point at the flange joint;
pressurizing contact in which a third electrode is pressed into contact with the welding point on the outer surface of the third member while the third member is in contact with the outer surface of the first member in the main body of the structure; process and
an energizing step of energizing between the first electrode and the third electrode in a state in which the second electrode is insulated from the first electrode and the third electrode and the first electrode or the third electrode is grounded; , and
An indirect spot welding method, wherein the position of the welding point with respect to the clamping point can be adjusted by rotating the third electrode in the circumferential direction about the axis of the first electrode. In claim 1,
The flange joint includes a covered portion covered by an exterior member and an exposed portion not covered by the exterior member,
An indirect spot welding method, wherein the clamping point is provided on the covered portion but not provided on the exposed portion. In claim 1 or claim 2,
The first member and the second member are spot welded at a plurality of flange welding points in the predetermined direction at the flange joint,
The indirect spot welding method, wherein the clamping point is arranged at a position different from the flange welding point. In any one of claims 1 to 3,
An indirect spot welding method, wherein the welding points are formed at regular intervals in the predetermined direction by adjusting the circumferential and radial positions of the third electrode with respect to the axial center of the first electrode. . In any one of claims 1 to 4,
The indirect spot welding method, wherein the body portion of the structure includes a hollow portion extending in the predetermined direction and formed by inner side surfaces of the first body portion and the second body portion. In any one of claims 1 to 5,
the first member and the second member are a side sill lane and a side sill inner, respectively, of a vehicle;
The indirect spot welding method, wherein the third member is a cab side outer. An apparatus for indirect spot welding a third member to an outer surface of a structure comprising a first member and a second member joined to the first member, comprising:
The first member has a first body portion extending in a predetermined direction and a first flange portion connected to an end of the first body portion and extending in the predetermined direction,
The second member has a second body portion extending in the predetermined direction and a second flange portion connected to an end of the second body portion and extending in the predetermined direction,
The structure includes a flange joint portion composed of the first flange portion and the second flange portion joined to each other, and a body portion formed by the first body portion and the second body portion,
The third member is welded to the outer surface of the first member forming the body portion of the structure at a plurality of welding points aligned in the predetermined direction,
a columnar first electrode arranged on the first flange portion side of the flange joint;
a second electrode that is physically integrated with the first electrode and arranged coaxially opposite the first electrode so as to sandwich the pinching point of the flange joint between the first electrode and the first electrode;
a third electrode that is physically integrated with the first electrode and is in pressure contact with the welding point on the outer surface of the third member;
the second electrode is insulated from the first electrode and the third electrode;
The first electrode or the third electrode is grounded,
The third electrode is rotatable in the circumferential direction of the axis of the first electrode,
An indirect spot welding apparatus, wherein the position of the welding point with respect to the clamping point can be adjusted by rotating the third electrode in the circumferential direction of the axis of the first electrode. In claim 7,
the third electrode is movable in a radial direction of the axis of the first electrode;
An indirect spot welding apparatus, wherein the welding points are formed at regular intervals in the predetermined direction by adjusting the position of the third electrode in the circumferential direction and the radial direction with respect to the axial center of the first electrode. . In claim 7 or claim 8,
The indirect spot welding apparatus, wherein the body portion of the structure includes a hollow portion extending in the predetermined direction and formed by inner side surfaces of the first body portion and the second body portion. a side sill lane extending in the front-rear direction and having first flange portions at both ends in the vertical direction;
A side sill inner having a second flange portion that extends in the front-rear direction and is joined to the first flange portion to form a flange joint portion, and that forms a hollow portion that extends in the front-rear direction inside the side sill lane while being joined to the side sill lane. and,
a cab side outer joined to the outer surface of the hollow portion of the side sill rain;
an exterior member disposed on the same side as the cab side outer with respect to the side sill rain and covering a portion of the flange joint portion but not covering the other portion;
A vehicle comprising
The first flange portion and the second flange portion are spot-welded at a plurality of flange welding points aligned in the front-rear direction,
the portion of the flange joint comprises the flange weld point and an indirect spot weld pinch point;
The vehicle, wherein the other portion of the flange joint includes the flange welding point but does not include the clamping point.

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