Connecting structure of dissimilar materials

Abstract

The utility model discloses a connecting structure for dissimilar materials. The connecting structure is used for connecting an upper-layer plate and a lower-layer plate. The tool comprises a fastener, the fastener comprises a flange part and a rod part which are connected, and the diameter of the flange part in the axial direction is larger than that of the rod part in the axial direction; the end, away from the rod part, of the flange part is provided with a first face attached to the upper electrode, and the end, away from the flange part, of the rod part is provided with a second face. After the fastener stamps and fixes the upper-layer plate, the fastener is fixed in the upper-layer plate in a penetrating manner, the second surface is attached to the lower-layer plate, and the side, away from the fastener, of the lower-layer plate is provided with a third surface used for being attached to the lower electrode; the diameter of the upper electrode is greater than that of the flange part; and the diameter of the lower electrode is greater than that of the rod part. By means of the structure, the welding nugget can be prevented from deviating through the electrode with the large diameter, and the spot welding efficiency is improved.

Description

Technical Field

[0001] The utility model relates to a spot welding technology, in particular to a connection structure of dissimilar materials. Background Art

[0002] The description in this section merely provides background information related to the disclosure of the present utility model and does not constitute prior art.

[0003] Resistance spot welding is a common welding technology used to connect two metal workpieces together. It is generally used in assembly lines such as automobiles, fans and trains. Resistance spot welding applies high voltage between the contact surfaces of two metal workpieces and passes a large current, using the heat generated by the contact resistance to melt or reach a plastic state, thereby forming a weld. After the power is turned off, the weld becomes firm under the continued pressure, connecting the metal workpieces together. The above process usually includes stages such as pre-pressing, welding, maintenance and rest.

[0004] In existing mass production, usually the fastener is first punched and fixed on one of the plates, and then one end of the other fastener is abutted against the surface of the other plate, and then one electrode is connected to the fastener and the other electrode is connected to the other plate, and then the electrodes are energized for spot welding. In the above process, since the fastener needs to be punched into one of the plates, the plate will rebound after punching, causing the theoretical preset position of the fastener to shift. At this time, if the combined error of the robot arm and the welding gun is added, it may cause the electrode to misalign with the fastener, and further cause the weld core to shift, resulting in weld failure. In another case, because the thickness of one of the plates is too large, the weld core may also shift after spot welding, affecting the welding quality.

[0005] Currently, there is no connection structure of dissimilar materials that can solve the above problems. Utility Model Content

[0006] The utility model aims to provide a connection structure of dissimilar materials, which can avoid the deviation of the welding core through the electrode with a larger diameter and improve the spot welding efficiency.

[0007] In order to achieve the above object, the utility model discloses the following connection structure of dissimilar materials, which is used to connect an upper plate and a lower plate, wherein the upper plate has a first thickness and the lower plate has a second thickness; wherein the connection structure of dissimilar materials comprises:

[0008] A fastener, the fastener comprising a flange portion and a rod portion connected to each other, the diameter of the flange portion along the axial direction being larger than the diameter of the rod portion along the axial direction; wherein the end of the flange portion away from the rod portion has a first surface for affixing to the upper electrode, and the end of the rod portion away from the flange portion has a second surface;

[0009] After the fastener punches and fixes the upper plate, the fastener is inserted and fixed in the upper plate, the second surface is bonded to the lower plate, and the side of the lower plate facing away from the fastener has a third surface for bonding with the lower electrode;

[0010] Wherein, the diameter of the upper electrode is greater than the diameter of the flange portion;

[0011] And, the diameter of the lower electrode is greater than the diameter of the rod.

[0012] Further, when the upper electrode is bonded to the first surface and the lower electrode is bonded to the third surface, the axial directions of the upper electrode, the lower electrode and the fastener overlap.

[0013] Furthermore, the diameters of the upper electrode and the lower electrode are the same.

[0014] Further, when the ratio of the first thickness to the second thickness is greater than 2.5, the fastener further includes a groove, the groove extends in the axial direction, and an opening of the groove is arranged on one side of the flange portion.

[0015] Furthermore, there is a third thickness between the bottom surface of the groove and the second surface, and a ratio of the third thickness to the second thickness is less than 2.5.

[0016] Furthermore, a side wall surface of the flange portion facing the rod portion is recessed from an edge position of the flange portion to an axial direction away from the rod portion.

[0017] Furthermore, when the lower electrode is attached to the third surface, the contact surface between the lower electrode and the third surface is configured as an arc-shaped surface that rises from the axial direction toward a direction away from the third surface.

[0018] Further, when the lower electrode is in contact with the third surface, the contact surface between the lower electrode and the third surface is set as a plane in contact with the third surface.

[0019] Furthermore, the upper plate is configured to be light metal, carbon fiber or non-steel material, and the upper plate is configured to be composed of one or more plates.

[0020] Furthermore, the lower plate is configured to be low carbon steel, medium carbon steel or advanced high strength steel, and the lower plate is configured to be composed of one or more plates.

[0021] By means of the above technical solution, the beneficial effects of the utility model are as follows:

[0022] 1. The connection structure of dissimilar materials of the utility model can be achieved by setting the diameter of the upper electrode larger than the diameter of the flange of the fastener, and the diameter of the lower electrode larger than the diameter of the rod of the fastener, so that after the fastener is stamped, even if the upper electrode or the lower electrode is offset and not coaxial with the existing fastener position, the position of the weld core after spot welding will not be horizontally offset, which significantly improves the yield rate of spot welding.

[0023] 2. The top of the connection structure of dissimilar materials of the utility model includes an arc-shaped portion. An axially extending groove is provided in the fastener, and the thickness between the bottom surface of the groove and the second surface is preset. The spot welding current is guided in the form of the fastener, so that even when the thickness of the upper plate significantly exceeds that of the lower plate, a relatively high-quality spot welding effect can still be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, 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 recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 It is a schematic cross-sectional view of a spot welding connection structure of dissimilar materials provided in an embodiment of this specification;

[0026] Figure 2 It is a cross-sectional schematic diagram of a fastener with a groove in a connection structure of dissimilar materials provided in an embodiment of this specification during spot welding;

[0027] Figure 3 It is a cross-sectional schematic diagram of a fastener with a groove in a connection structure of dissimilar materials provided in an embodiment of this specification;

[0028] In the figure: 100, upper plate; 200, lower plate; 200a, third surface; 1, fastener; 11, flange portion; 12, rod portion; 1a, first surface; 1b, second surface; 13, groove; 111, recess; 2, upper electrode; 3, lower electrode. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this specification.

[0030] In the description of the present utility model, it should be noted that the terms "upper", "middle", "lower", "inner", "outer", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model. The terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. The following describes the implementation method of the present utility model based on its overall structure.

[0031] See also Figure 1 , is a connection structure of dissimilar materials of this embodiment, used to connect an upper plate 100 and a lower plate 200, the upper plate 100 has a first thickness, and the lower plate 200 has a second thickness; wherein the connection structure of dissimilar materials includes:

[0032] A fastener 1, comprising a flange portion 11 and a rod portion 12 connected to each other, wherein the diameter of the flange portion 11 along the axial direction is greater than the diameter of the rod portion 12 along the axial direction; wherein an end of the flange portion 11 away from the rod portion 12 has a first surface 1a for contacting with the upper electrode 2, and an end of the rod portion 12 away from the flange portion 11 has a second surface 1b;

[0033] After the fastener 1 is punched and fixed to the upper plate 100, the fastener 1 is inserted and fixed in the upper plate 100, and the second surface 1b is bonded to the lower plate 200, and the side of the lower plate 200 facing away from the fastener 1 has a third surface 200a for bonding with the lower electrode 3;

[0034] Wherein, the diameter of the upper electrode 2 is greater than the diameter of the flange portion 11;

[0035] Also, the diameter of the lower electrode 3 is greater than the diameter of the rod portion 12 .

[0036] Through the above structure, when in use, the operator first prepares the preset fastener 1, and then points the rod 12 of the fastener 1 toward the preset position of the upper plate 100, and performs a stamping operation of the fastener 1 on the upper plate 100, so that the rod 12 can punch a through hole in the upper plate 100, and stamp part of the material in the original upper plate 100 to the position between the flange 11 and the rod 12 in the fastener 1, so that the fastener 1 and the upper plate 100 form an interference fit or a stuck state, that is, the upper plate 100 and the fastener 1 are completely fixed, and at the same time, the rod 12 after stamping and fixing partially extends to the upper plate 100. The outer side of the layer plate 100, and then the second side 1b of the position where the rod 12 extends out can be placed in contact with the lower layer plate 200, and the upper electrode 2 and the lower electrode 3 can be energized, and during the energization process, the upper electrode 2 and the lower electrode 3 are squeezed toward the direction of the fastener 1 to perform spot welding, so that the fastener 1, the upper plate 100 and the partial area of ​​the lower plate 200 are subjected to the action of large current and extrusion, and deformed in a direction not parallel to the axial direction in a short time, and a new stable weld nugget is melted in the preset area, so that the partial area of ​​the fastener 1, the upper plate 100 and the lower plate 200 is fixed together, completing the final spot welding operation.

[0037] It is worth noting that due to the influence of stamping, unnecessary vibration will inevitably occur after the upper plate 100 is subjected to force, which may cause the actual position of the fastener 1 after stamping and before spot welding to deviate from the preset position. Therefore, if the spot welding operation is continued in this case, the upper electrode 2 and the lower electrode 3 may be misaligned with the fastener 1, resulting in unstable deviations in the current flow direction, resulting in deviations in the position of the weld nugget formation, affecting the welding quality.

[0038] However, in this embodiment, the diameters of the upper electrode 2 and the lower electrode 3 are significantly larger than the diameters of the flange portion 11 and the rod portion 12 in the fastener 1. Therefore, even if the position of the fastener 1 deviates from the preset position after stamping, the upper electrode 2 and the lower electrode 3 can still completely cover the fastener 1. That is to say, after power is turned on, the current between the upper electrode 2 and the lower electrode 3 can still occur along the specified direction (such as the middle position of the axial direction), and the weld core is formed at the preset position, which can fully meet the needs of this spot welding.

[0039] Furthermore, this embodiment is particularly suitable for use when the upper plate 100 is a thinner plate. Because when the upper plate 100 is a thin plate, it is more susceptible to the impact of stamping vibration. When the upper electrode 2 is bonded to the first surface 1a and the lower electrode 3 is bonded to the third surface 200a, the axial directions of the upper electrode 2, the lower electrode 3, and the fastener 1 coincide. Specifically, although the relative positions of the upper electrode 2, the lower electrode 3, and the fastener 1 may be offset after stamping, the default position still maintains the coaxiality between the upper electrode 2, the lower electrode 3, and the fastener 1, and the portion of the upper electrode 2 that is larger than the diameter of the flange portion 11 is used to compensate for the deviation that may cause the projection surface of the flange portion 11 on the upper plate 100 along the axial direction to deviate from the projection surface of the upper electrode 2 on the upper plate 100 along the axial direction. Similarly, the portion of the lower electrode 3 that is larger than the diameter of the rod 12 is used to compensate for the deviation that may cause the axial projection of the rod 12 on the lower plate 200 to deviate from the axial projection of the lower electrode 3 on the lower plate 200.

[0040] Furthermore, if Figure 1 As shown, in this embodiment, the diameters of the upper electrode 2 and the lower electrode 3 are the same. Electrodes of the same diameter can ensure that the current is evenly distributed in the welding area, which helps to form a uniform nugget, thereby improving the quality and strength of the weld, and when the upper electrode 2 and the lower electrode 3 apply pressure toward the fastener 1, electrodes of the same size can evenly distribute the pressure, which helps to reduce unnecessary deformation of the fastener 1, especially in the welding of thin plate materials. Of course, using the upper electrode 2 and the lower electrode 3 of the same diameter can also increase the standardization of equipment production, so as to facilitate later maintenance and reduce costs.

[0041] Furthermore, if Figure 2-3 As shown, when the ratio of the first thickness to the second thickness is greater than 2.5, the fastener 1 further includes a groove 13, the groove 13 extends in the axial direction, the opening of the groove 13 is arranged on one side of the flange portion 11, and a third thickness is provided between the bottom surface of the groove 13 and the second surface 1b, and the ratio of the third thickness to the second thickness is less than 2.5. Specifically, in a general spot welding operation environment, the ratio of the first thickness to the second thickness is less than 2.5, so as to avoid the upper plate 100 being too much thicker than the lower plate 200 and the length in the axial direction being too long, resulting in the weld nugget being offset in the axial direction when the weld nugget is formed, and failing to be formed in the preset area, thereby affecting the effect of spot welding.

[0042] By setting the groove 13, the space of the groove 13 can be used to accommodate the deformed material during the process of the upper electrode 2 applying pressure to the flange portion 11, and the thickness ratio between the upper plate 100 and the lower plate 200 can be indirectly reduced. For example, in the present embodiment, the thickness of the upper plate 100 is 3mm, the thickness of the lower plate 200 is 0.7mm, the thickness difference between the upper plate 100 and the lower plate 200 is more than 2.5 times, and the thickness between the bottom surface of the groove 13 and the second surface 1b is 1.5mm, that is, the ratio of the third thickness to the second thickness is less than 2.5. In the present embodiment, the actual physical thickness between the upper electrode 2 and the lower plate 200 is indirectly reduced, and the current can flow between the upper electrode 2 and the lower electrode 3 after passing through the fastener 1 area with a relatively small thickness. Spot welding is performed in the case of the present embodiment, which can effectively reduce the degree of displacement of the weld core along the axial direction.

[0043] Furthermore, if Figure 3 As shown, the side wall of the flange portion 11 facing the rod portion 12 is recessed 111 from the edge of the flange portion 11 to the axial direction away from the rod portion 12. By setting the recess 111, when the fastener 1 impacts the upper plate 100, the flow direction of the material of the upper plate 100 can be guided by the recess 111 to the area between the flange portion 11 and the rod portion 12, so that the fastener 1 after stamping has stronger fixing stability in the radial direction, which helps to improve the product quality of this embodiment.

[0044] Furthermore, if Figure 1 As shown, when the lower electrode 3 is attached to the third surface 200a, the contact surface between the lower electrode 3 and the third surface 200a is set as an arc surface that rises from the axial direction away from the third surface 200a. Most of the heat in the welding area is dissipated by conduction from the upper electrode 2 and the lower electrode 3. Therefore, the setting of the arc surface can effectively improve the heat dissipation effect between the lower electrode 3 and the lower plate 200.

[0045] In another embodiment, when the lower electrode 3 is in contact with the third surface 200a, the contact surface between the lower electrode 3 and the third surface 200a is set to be a plane in contact with the third surface 200a. The plane lower electrode 3 can provide a more uniform pressure distribution, which has a significant beneficial effect on ensuring welding quality and avoiding workpiece deformation, but the heat dissipation efficiency may be slightly lower, and it can be arranged according to the actual welding strength requirements.

[0046] Further, the upper plate 100 is configured to be a light metal, carbon fiber or non-steel material, and the upper plate 100 is configured to be composed of one or more plates. Specifically, the light metal, carbon fiber or non-steel material has a lower density and good corrosion resistance, which enables the upper plate 100 to reduce the weight of the structure and provide the necessary strength. The lower plate is configured to be low carbon steel, medium carbon steel or advanced high strength steel, and the lower plate is configured to be composed of one or more plates. Specifically, low carbon steel, medium carbon steel or advanced high strength steel has high strength and toughness, and can withstand a large load. In the spot welding process, the thermal conductivity and electrical conductivity of low carbon steel, medium carbon steel or advanced high strength steel help to effectively transfer heat and current, thereby forming a stable molten core at the joint surface of the fastener 1 and the lower plate 200. The specific material selection can be regulated according to cost requirements.

[0047] Although different specific embodiments are mentioned in the content of this application, this application is not limited to the situations described in the industry standards or embodiments, etc. Some industry standards or slightly modified implementation plans based on the implementation of the custom methods or embodiments can also achieve the same, equivalent or similar, or predictable implementation effects after deformation of the above embodiments. The embodiments of data acquisition, processing, output, judgment methods, etc. after these modifications or deformations can still fall within the scope of the optional implementation plans of this application.

[0048] Although the present application has been described through embodiments, those skilled in the art will appreciate that there are many modifications and changes to the present application without departing from the spirit of the present application. It is intended that the attached embodiments include these modifications and changes without departing from the present application.

Claims

1. A connection structure of dissimilar materials, used to connect an upper plate and a lower plate, wherein the upper plate has a first thickness and the lower plate has a second thickness; characterized in that: The connection structure of the dissimilar materials comprises: A fastener, the fastener comprising a flange portion and a rod portion connected to each other, the diameter of the flange portion along the axial direction being larger than the diameter of the rod portion along the axial direction; wherein the end of the flange portion away from the rod portion has a first surface for affixing to the upper electrode, and the end of the rod portion away from the flange portion has a second surface; After the fastener punches and fixes the upper plate, the fastener is inserted and fixed in the upper plate, the second surface is bonded to the lower plate, and the side of the lower plate facing away from the fastener has a third surface for bonding with the lower electrode; Wherein, the diameter of the upper electrode is greater than the diameter of the flange portion; And, the diameter of the lower electrode is greater than the diameter of the rod.

2. The connecting structure of dissimilar materials according to claim 1, characterized in that: When the upper electrode is bonded to the first surface and the lower electrode is bonded to the third surface, the axial directions of the upper electrode, the lower electrode and the fastener overlap.

3. The connection structure of dissimilar materials according to claim 1, characterized in that: The upper electrode and the lower electrode have the same diameter.

4. The connection structure of dissimilar materials according to claim 1, characterized in that: When the ratio of the first thickness to the second thickness is greater than 2.5, the fastener further includes a groove extending in the axial direction, and an opening of the groove is arranged at one side of the flange portion.

5. The connection structure of dissimilar materials according to claim 4, characterized in that: A third thickness is provided between the bottom surface of the groove and the second surface, and a ratio of the third thickness to the second thickness is less than 2.

5.

6. The connecting structure of dissimilar materials according to claim 1, characterized in that: A side wall surface of the flange portion facing the rod portion is recessed from an edge position of the flange portion to an axial direction away from the rod portion.

7. The connecting structure of dissimilar materials according to claim 1, characterized in that: When the lower electrode is attached to the third surface, the contact surface between the lower electrode and the third surface is configured as an arc-shaped surface that rises from the axial direction toward a direction away from the third surface.

8. The connecting structure of dissimilar materials according to claim 1, characterized in that: When the lower electrode is in contact with the third surface, the contact surface between the lower electrode and the third surface is set as a plane in contact with the third surface.

9. The connecting structure of dissimilar materials according to claim 1, characterized in that: The upper plate is configured to be light metal, carbon fiber or non-steel material, and the upper plate is configured to be composed of one or more plates.

10. The connecting structure of dissimilar materials according to claim 1, characterized in that: The lower plate is configured to be low carbon steel, medium carbon steel or advanced high strength steel, and the lower plate is configured to be composed of one or more plates.

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