A single-sided spot welding structure and welding method

Abstract

The present invention relates to the field of welding technology, and discloses a single-sided spot welding structure and a welding method, wherein the structure comprises two overlapping sheet metal parts, and a gap is formed at a predetermined overlapping position; at least one of the sheet metal parts is formed with at least one boss portion protruding toward the other sheet metal part at a position corresponding to the gap, and the boss portion contacts the sheet metal part it faces when overlapping. The present invention can solve the problem of the inability to weld due to the existence of gaps in sheet metal and the instability of the gaps in actual production, thereby realizing the weldability of sheet metal overlaps; eliminating the constraint that single-sided welding must provide support force on the opposite side of the weld, thereby creating application conditions for single-sided welding on various structures of the body-in-white; the boss portion can be stamped and formed synchronously with other features of the sheet metal, without the need for separate processing steps.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a single-sided spot welding structure and a welding method. Background Art

[0002] In the field of automobile welding production, single-sided welding is a connection process that is often used to fix the inner and outer panels after the door cover is rolled. In this connection method, the welding electrode contacts the outer panel flange, and the other ground electrode contacts the inner panel. The opposite side of the welding electrode is supported by a fixture or a rolling die. After the electrode provides pressure, the outer panel flange and the inner panel are energized to form a weld core.

[0003] The structure of the car body is complex, and single-sided welding has advantages such as small operating space requirements. However, the single-sided welding process has high requirements for the gap between the two sheet metals. The sheet metals must fit together at the welding point, and there must be a clamp on the opposite side of the welding electrode to provide support. Therefore, the single-sided welding process cannot be applied to welding surfaces with complex sheet metal structures and unstable gaps, such as the overlap of cavity beam structures and flat plates, and poor ergonomics on the other side of the overlap. Therefore, the existing single-sided welding is only used at the overlap of the inner and outer panels after the door cover is rolled, and the application scenario is single.

[0004] Therefore, the prior art needs to be improved urgently. Summary of the invention

[0005] The purpose of the present invention is: the present invention provides a single-sided spot welding structure and a welding method to solve the technical problem that the existing single-sided welding process cannot be applied to welding surfaces with complex sheet metal structures and unstable gaps, resulting in a single application scenario.

[0006] In order to achieve the above object, the present invention provides a single-sided spot welding structure, comprising two overlapped sheet metal parts, and a gap is formed at a predetermined overlapped position;

[0007] At least one of the sheet metal parts is formed with at least one boss portion protruding toward another sheet metal part at a position corresponding to the gap, and the boss portion contacts the sheet metal part it faces when overlapping.

[0008] In some embodiments, when one boss portion is formed on each of the two sheet metal parts, the two boss portions are spaced apart by a predetermined distance.

[0009] In some embodiments, when at least two boss portions are formed on one of the sheet metal parts and at least one boss portion is formed on the other sheet metal part, the boss portions on the two sheet metal parts are arranged alternately.

[0010] In some embodiments, the highest point of the boss portion is a welding surface.

[0011] In some embodiments, the side surface of the boss portion forms an inclined side surface from the highest point to the lowest point from the inside to the outside.

[0012] In some embodiments, the height of the boss portion is between 0.2 mm and 2 mm.

[0013] In some embodiments, the shape of the welding surface is a straight line, and its width is between 0.5-4 mm and its length is between 5-10 mm.

[0014] In some embodiments, the welding surface is circular in shape, and its diameter is between 4 and 20 mm.

[0015] In some embodiments, the surface curvature of the welding surface is consistent with the surface curvature of the sheet metal part it contacts.

[0016] The present application also provides a single-sided spot welding method, based on any one of the single-sided spot welding structures described in the above claims, comprising the following steps:

[0017] S1, placing one sheet metal part on another sheet metal part;

[0018] S2. When the boss portion is provided on the sheet metal part located above, the boss portion is brought into contact with the sheet metal part located below, and the welding clamp is pressed on the surface of the sheet metal part located above corresponding to the contact portion;

[0019] When the boss portion is provided on the sheet metal part located below, the boss portion is brought into contact with the sheet metal part located above, and the welding clamp is pressed on the surface of the sheet metal part located above corresponding to the contact portion;

[0020] S3, starting welding, the two sheet metal parts and the boss parts arranged thereon are heated and melted at the contact point to form a weld nugget.

[0021] Compared with the prior art, the one-side spot welding structure and welding method of the embodiment of the present invention have the following beneficial effects:

[0022] First, it can solve the problem of poor overlap gap of sheet metal at the welding position, especially the unstable overlap gap of multiple lap joints in complex structures, thereby solving the problem of welding failure caused by gaps in sheet metal and unstable gaps in actual production, and realizing the weldability of sheet metal overlap.

[0023] Second, single-sided electrode pressure is used to weld using the strength that the sheet metal structure can withstand. No mold or fixture is required to provide support on the opposite side, eliminating the constraint that single-sided welding must provide support on the opposite side of the weld, creating application conditions for single-sided welding on various structures of the body-in-white.

[0024] Third, the gap compensation structure can be stamped and formed simultaneously with other features of the sheet metal, without the need for separate processing steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the structure when two sheet metal parts are overlapped in reality;

[0027] Figure 2 It is a schematic diagram of the structure when two sheet metal parts are overlapped in theory;

[0028] Figure 3 is a structural schematic diagram of a first protrusion being provided on a first sheet metal part in an embodiment of the present invention;

[0029] Figure 4 is a structural schematic diagram of a second protrusion being provided on a second sheet metal part in an embodiment of the present invention;

[0030] Figure 5 is a structural schematic diagram of an embodiment of the present invention in which a first protruding portion and a second protruding portion are simultaneously provided on a first sheet metal part and a second sheet metal part;

[0031] Figure 6 is a schematic diagram of the structure in which the welding clamp is pressed on the first sheet metal part;

[0032] Figure 7 is a schematic diagram of the structure in which the welding clamp is pressed on the first sheet metal part;

[0033] Figure 8 is a schematic diagram of the three-dimensional structure of the first sheet metal part and the first protrusion;

[0034] Fig. 9 yes Figure 8 A top view of

[0035] Fig.10 is a schematic diagram of the three-dimensional structure of the second sheet metal part and the second protrusion;

[0036] Fig.11 yes Fig.10 A top view of

[0037] In the figure, 1 is a first sheet metal part; 2 is a second sheet metal part; 11 is a first boss part; 12 is a second boss part. DETAILED DESCRIPTION

[0038] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0039] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “top” and “bottom” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0042] like Figure 1 As shown, a single-sided spot welding structure according to an embodiment of the present invention includes two overlapping sheet metal parts. Figure 1 It is represented as a first sheet metal part 1 located at the top and a second sheet metal part 2 located at the bottom.

[0043] Figure 1 This is a schematic diagram of the structure when two sheet metal parts are overlapped in reality. Figure 2 This is a schematic diagram of the structure when two sheet metal parts are overlapped in theory. Figure 1 It can be seen that, compared with the theory, in reality, gaps will inevitably form at certain positions when two sheet metal parts are overlapped.

[0044] The solution proposed in the present application is that at least one sheet metal part is formed with at least one boss portion protruding toward another sheet metal part at a position corresponding to the gap, and the boss portion contacts the sheet metal part it faces when overlapping.

[0045] The above scheme mainly includes the following situations:

[0046] The first one, see Figure 3 , only the first sheet metal part 1 is formed with a first boss portion 11 protruding toward the second sheet metal part 2 at a position corresponding to the gap, and the first boss portion 11 contacts the surface of the second sheet metal part 2 when overlapped. There can be one or more first boss portions 11, and when multiple are provided, they can be arranged at a certain distance. The back side of the first boss portion 11 away from the second sheet metal part 2 is an opening, and the back side opening faces outward.

[0047] The second type, see Figure 4 , only the second sheet metal part 2 is formed with a second boss portion 12 protruding toward the first sheet metal part 1 at the position corresponding to the gap, and the second boss portion 12 contacts the surface of the first sheet metal part 1 when overlapping. There can be one or more second boss portions 12, and when multiple are provided, they can be arranged at a certain distance. The back side of the second boss portion 12 away from the first sheet metal part 1 is open, and the back side opening faces inward.

[0048] The third type, see Figure 5 At least one first boss portion 11 protruding toward the second sheet metal part 2 is formed at a position of the first sheet metal part 1 corresponding to the gap, and the first boss portion 11 contacts the surface of the second sheet metal part 2 when overlapping. And at least one second boss portion 12 protruding toward the first sheet metal part 1 is formed at a position of the second sheet metal part 2 corresponding to the gap, and the second boss portion 12 contacts the surface of the first sheet metal part 1 when overlapping.

[0049] In some embodiments, for the third case, when there is only one first boss portion 11 and one second boss portion 12, the first boss portion 11 and the second boss portion 12 are spaced apart by a predetermined distance, that is, Figure 5 As shown, the predetermined distance can be determined according to the gap size.

[0050] In some embodiments, for the third case, when at least two bosses are provided on one of the sheet metal parts and at least one boss is provided on the other sheet metal part, the bosses on the two sheet metal parts are arranged alternately. For example, when two first bosses 11 are provided on the first sheet metal part 1 and a second boss 12 is provided on the second boss 12, the bosses are arranged alternately at intervals, that is, from top to bottom, they are: first boss 11, second boss 12, first boss 11. In this case, it is preferred that the second boss 12 is provided at the midpoint of the interval between the two first bosses 11. For another example, when two first bosses 11 are provided on the first sheet metal part 1 and two second bosses 12 are provided on the second boss 12, the bosses are arranged alternately at intervals, that is, from top to bottom, they are: first boss 11, second boss 12, first boss 11, second boss 12. In this case, the second boss portion 12 is preferably disposed at the midpoint of the interval between two adjacent first boss portions 11. The technician should understand that the above staggered arrangement is only a preferred embodiment, and in fact the number and arrangement order of the first boss portions 11 and the second boss portions 12 can be adjusted according to the actual situation of the gap.

[0051] The single-sided spot welding method applicable to the above-mentioned single-sided spot welding structure mainly includes the following steps:

[0052] S1, placing the first sheet metal part 1 on the second sheet metal part 2;

[0053] S2, see Figure 6 When the first sheet metal part 1 is provided with a first boss part 11, the first boss part 11 is brought into contact with the surface of the second sheet metal part 2, and the welding clamp is pressed at the opening of the first boss part 11;

[0054] See also Figure 7 When the second sheet metal part 2 is provided with a second boss portion 12, the second boss portion 12 is brought into contact with the surface of the first sheet metal part 1, and the welding clamp is pressed on the surface of the first sheet metal part 1 corresponding to the contact point;

[0055] S3, starting welding, the first sheet metal part 1, the second sheet metal part 2 and the boss parts arranged thereon are heated and melted at the contact point to form a weld nugget.

[0056] When both the first sheet metal component 1 and the second sheet metal component 2 are provided with bosses, steps S2 - S3 are performed on each boss.

[0057] In summary, the present invention arranges a gap compensation structure (boss portion) on at least one side of the sheet metal, and makes the gap compensation structure contact and fit with the sheet metal on the other side. The single-sided welding clamp provides unidirectional pressure from the compensation structure side or the opposite side for welding. During the welding process, the gap compensation structure and the sheet metal on the contact side are fitted and energized, the gap compensation structure melts, and the height of the gap compensation structure is reduced to form a nearly flat post-weld mark, thereby successfully welding.

[0058] Compared with the prior art, the present invention has at least the following beneficial effects:

[0059] First, it can solve the problem of poor overlap gap of sheet metal at the welding position, especially the unstable overlap gap of multiple lap joints in complex structures, thereby solving the problem of welding failure caused by gaps in sheet metal and unstable gaps in actual production, and realizing the weldability of sheet metal overlap.

[0060] Second, single-sided electrode pressure is used to weld using the strength that the sheet metal structure can withstand. No mold or fixture is required to provide support on the opposite side, eliminating the constraint that single-sided welding must provide support on the opposite side of the weld, creating application conditions for single-sided welding on various structures of the body-in-white.

[0061] Third, the gap compensation structure can be stamped and formed simultaneously with other features of the sheet metal, without the need for separate processing steps.

[0062] In summary, the single-sided spot welding structure and welding method proposed in the present invention can be applied to conventional spot welding processes and single-sided welding processes. There are no special requirements for welding equipment. It can be applied to various vehicle body structures such as complex structures and cavity structures, and has a wide range of applicable occasions.

[0063] In some embodiments, the highest points of the first boss portion 11 and the second boss portion 12 are welding surfaces. During welding, the welding clamp exerts a certain pressure when pressing on the surface of the sheet metal. That is, in theory, even if the highest point of the boss portion is in the shape of a point, under the pressure of the welding clamp, it will be slightly deformed into a surface with a smaller area, and will be in contact with and fit the sheet metal on the contact side. Therefore, even if the highest point of the boss portion is in the shape of a point, as long as its height is sufficient to be in contact with and fit the sheet metal on the contact side and energized, a single-sided welding process can be achieved. Setting the highest point of the boss portion in the shape of a surface is a preferred embodiment, which can increase the contact area between the boss portion and the sheet metal, so that it can still be in good contact with and fit the sheet metal on the contact side without relying on the pressure of the welding clamp, thereby ensuring a smooth welding process.

[0064] In some embodiments, the curvature of the welding surface is consistent with the curvature of the surface of the sheet metal part it contacts. In practical applications, the boss portion can be provided at the flat section of the sheet metal part, such as Figure 3-5. The boss portion may also be provided at the curved surface section of the sheet metal part, preferably at a curved surface with a curvature radius of more than 50 mm. Regardless of whether the boss portion is provided at the flat section or the curved section of the sheet metal part, the welding surface may be flat or curved. As long as the height of the welding surface is sufficient to be in contact with and fit the sheet metal part on the contact side and energized, a single-sided welding process can be achieved. This is because, under the pressure of the welding clamp, the shape of the welding surface will change, and the slight differences between the flat and curved shapes will be eliminated, and will not affect the implementation of the present application. Setting the surface curvature of the welding surface to be consistent with the surface curvature of the sheet metal part in contact with it is a preferred implementation method, which enables the entire contact surface of the boss portion to contact the sheet metal part, maximizes the contact area, and further ensures that the welding surface is in contact with and fits the sheet metal part on the contact side, thereby ensuring a smooth welding process.

[0065] In some embodiments, the shape of the welding surface may be circular, straight, cross-shaped, rectangular, etc., and the three-dimensional shape of the boss portion matches the shape of the welding surface.

[0066] In some embodiments, see Figure 8 -9, taking the first sheet metal part 1 and the first raised portion 11 as an example, the shape of the welding surface is a straight line, and its width is between 0.5-4mm, that is, 0.5mm, 1mm, 1.5mm, 2mm, 2.6mm, 3mm, 3.7mm or 4mm, of which 1.5mm is preferred; its length is between 5-10mm, that is, 5mm, 5.5mm, 6mm, 7mm, 8mm, 9mm or 10mm, of which 7mm is preferred. The three-dimensional shape of the boss portion matches the shape of the straight line welding surface, and as shown in the figure, the boss portion is a strip-shaped protrusion.

[0067] In some embodiments, see Fig.10 -11, taking the second sheet metal part 2 and the second raised portion 12 as an example, the shape of the welding surface is circular, and its diameter is between 4 and 20 mm, that is, 4 mm, 5 mm, 6 mm, 7.5 mm, 9.6 mm, 11 mm, 15 mm, 18 mm or 20 mm, of which 6 mm is preferred. The three-dimensional shape of the boss portion matches the shape of the circular welding surface, and as shown in the figure, the boss portion appears as a circular protrusion.

[0068] Those skilled in the art should understand that the shapes of the bosses and the shapes of the welding surfaces provided on the two sheet metal parts can be the same or different, and any combination of the above shapes and sizes can be selected according to actual conditions. That is, as in the above example, the first sheet metal part 1 and the first raised part 11 can adopt a circular structure or other shape structures, and the second sheet metal part 2 and the second raised part 12 can adopt a straight structure or other shape structures. The above example is only a preferred embodiment and does not constitute a limitation to the present application.

[0069] In some embodiments, the height of the boss portion is between 0.2-2 mm. During actual manufacturing, the protruding height of the boss portion is determined according to the width of the gap formed between the two sheet metal parts. Generally speaking, the boss portion of the present application is generally set at a gap with a width of 0.2-2 mm, so the height of the boss portion is between 0.2-2 mm (including the endpoint values), and 0.5-1 mm can be preferably selected according to the product structure, that is, 0.5 mm, 0.6 mm, 0.75 mm, 0.9 mm or 1 mm can be selected.

[0070] In some embodiments, participating Figure 1 -7. Figure 8 and Fig.10 The side surface of the boss portion forms an inclined side surface from the highest point to the lowest point from the inside to the outside. The inclined side surface can be as follows Figure 1 -7 shows a smooth transition side. But in fact, due to the influence of the stamping process, it may form Figure 8 and Fig.10 The side surface of the boss portion is set to be inclined, which is a preferred embodiment, and the inclined surfaces in the above two cases have little difference in actual use effects.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A single-sided spot welding method, applicable to a single-sided spot welding structure, wherein the single-sided spot welding structure comprises two overlapped sheet metal parts, and a gap is formed at a predetermined overlapped position; at least one of the sheet metal parts is formed with at least one boss portion protruding toward the other sheet metal part at a position corresponding to the gap, and the boss portion contacts the sheet metal part it faces when overlapping; wherein, The highest point of the boss portion is a welding surface, and the welding surface contacts and is welded to the sheet metal part it faces; It is characterized by comprising the following steps: S1, placing one sheet metal part on another sheet metal part; S2. When the boss portion is provided on the sheet metal part located below, the boss portion is brought into contact with the sheet metal part located above, and the welding clamp is pressed on the surface of the sheet metal part located above corresponding to the contact portion; S3, starting welding, the two sheet metal parts and the boss parts arranged thereon are heated and melted at the contact point to form a weld nugget.

2. The single-sided spot welding method according to claim 1, characterized in that: When one boss portion is formed on each of the two sheet metal parts, the two boss portions are spaced apart by a predetermined distance.

3. The single-sided spot welding method according to claim 2, characterized in that: When at least two boss portions are formed on one of the sheet metal parts and at least one boss portion is formed on the other sheet metal part, the boss portions on the two sheet metal parts are arranged alternately.

4. The single-sided spot welding method according to claim 1, characterized in that: The side surface of the boss portion forms an inclined side surface from the highest point to the lowest point from the inside to the outside.

5. The single-sided spot welding method according to claim 1, characterized in that: The height of the boss portion is between 0.2-2 mm.

6. The single-sided spot welding method according to claim 1 or 5, characterized in that: The shape of the welding surface is a straight line, and its width is between 0.5-4mm and its length is between 5-10mm.

7. The single-sided spot welding method according to claim 1 or 5, characterized in that: The welding surface is circular in shape, and its diameter is between 4 and 20 mm.

8. The single-sided spot welding method according to claim 1, characterized in that: The surface curvature of the welding surface is consistent with the surface curvature of the sheet metal part it contacts.

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