Gluing resistance spot welding pretreatment device

Abstract

The utility model discloses a glue joint resistance spot welding pretreatment device which comprises an installation module, a welding module, a welding module and a control module. The preheating module comprises an electromagnetic wave generator arranged on the mounting module, and the electromagnetic wave generator is used for preheating a welded workpiece; according to the gluing resistance spot welding pretreatment device provided by the utility model, the preheating module adopting infrared heating is additionally arranged on the spot welding robot body, so that the welding spot area of a welded piece can be quickly preheated, the flowability of structural adhesive is improved, the structural adhesive is ensured to be completely extruded, and the gluing resistance spot welding burst point or burn-through frequency is reduced; meanwhile, as the electromagnetic wave generator can emit high-frequency electromagnetic waves to bombard the metal surface, falling of an oxide layer can be promoted, cleaning and activation of the metal surface are facilitated, welding defects such as air holes or cracks can be effectively reduced, and the method is particularly suitable for resistance spot welding of an aluminum vehicle body structure.

Description

Technical Field

[0001] The utility model belongs to the technical field of welding, and in particular relates to a pretreatment device for adhesive resistance spot welding. Background Art

[0002] Glue-jointed resistance spot welding is a process in which structural adhesive is first applied between the overlapping layers of the welded plates, pressure is applied through electrodes after the plates are assembled, and finally power is applied to complete the welding connection through resistance heat. This welding method has reliable connection and is conducive to automated welding through spot welding robots. It is currently a commonly used connection method in aluminum body structures. Because structural adhesive is a non-conductive medium, it has poor fluidity under low temperature conditions (below room temperature 10°C). Currently, welding equipment on the market generally uses power-on preheating and pre-pressing to complete pretreatment before welding. This pretreatment method does not generate sufficient resistance heat due to the small area of ​​the electrode cap and the power-on preheating time is usually very short. The structural adhesive layer at the spot weld cannot be fully heated, and the complete extrusion of the structural adhesive at the spot weld cannot be well guaranteed, resulting in a high frequency of explosion points or burn-throughs in glue-jointed resistance spot welding. In addition, for metal plates such as aluminum alloy and magnesium alloy, which are prone to forming high-impedance and high-melting-point oxide films on their surfaces, the existing electric preheating method cannot remove the oxide film. During resistance spot welding, the contact resistance between the electrode cap and the welded plate is large, resulting in large heat generation at the interface, rapid ablation and wear of the electrode cap, and a short life of the electrode cap. In addition, the oxide film can easily cause slag inclusions to produce pores and cracks, affecting the quality of spot welding.

[0003] Therefore, there is an urgent need to provide a new pretreatment device, which is expected to reduce the frequency of explosion points or burn-throughs in adhesive resistance spot welding, reduce welding defects such as pores or cracks, and thus improve the welding quality of adhesive resistance spot welding. Utility Model Content

[0004] In view of this, the purpose of the present invention is to provide a pretreatment device for adhesive resistance spot welding. By adopting this pretreatment device, the frequency of explosion points or burn-throughs in adhesive aluminum spot welding can be effectively reduced, and welding defects such as pores or cracks can be reduced, thereby improving the welding quality of adhesive resistance spot welding.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a pretreatment device for adhesive resistance spot welding, comprising: an installation module, which is arranged on the spot welding robot body; a preheating module, the preheating module comprising an electromagnetic wave generator arranged on the installation module, and the electromagnetic wave generator is used to complete the preheating of the workpiece to be welded.

[0006] Furthermore, the electromagnetic wave generator is an infrared generator or a laser generator.

[0007] Furthermore, the electromagnetic wave generator is rotatably mounted on the mounting module in a lockable manner.

[0008] Furthermore, the mounting module includes a connecting rod and a driving assembly fixedly mounted on the spot welding robot body, the connecting rod is connected to the driving assembly and can move axially under the drive of the driving assembly, and the electromagnetic wave generator is arranged at the lower end of the connecting rod.

[0009] Furthermore, the driving assembly includes a mounting base fixedly connected to the spot welding robot body and a telescopic cylinder fixedly mounted on the mounting base, and the upper end of the connecting rod is fixedly connected to the working end of the telescopic cylinder.

[0010] Furthermore, a protective tube is provided at the lower end of the connecting rod, the electromagnetic wave generator is fixed in the protective tube, and the protective tube is rotatably mounted on the connecting rod in a lockable manner; the protective tube is a metal protective tube.

[0011] Furthermore, the preheating module also includes an infrared temperature measuring probe and a controller. The infrared temperature measuring probe is fixedly installed on the outer peripheral surface of the protective tube to detect the temperature of the welding point area. The controller is connected to the infrared temperature measuring probe.

[0012] Furthermore, the connecting rod is arranged in parallel with the upper electrode rod of the spot welding robot.

[0013] Furthermore, the installation module also includes a limiting guide fixedly installed on the spot welding robot body, the limiting guide is provided with a guide hole, and the connecting rod is slidably installed in the guide hole.

[0014] Furthermore, the connecting rod includes an upper connecting rod and a lower connecting rod detachably connected to the lower end of the upper connecting rod, and the electromagnetic wave generator is arranged at the lower end of the lower connecting rod.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The adhesive resistance spot welding pretreatment device provided by the utility model can effectively improve the welding quality of adhesive resistance spot welding. Specifically, by adding a preheating module using infrared heating to the spot welding robot body, the preheating of the welding point area of ​​the welded part can be quickly completed, thereby improving the fluidity of the structural adhesive, ensuring the complete extrusion of the structural adhesive, and reducing the frequency of explosion points or burn-throughs in adhesive resistance spot welding; at the same time, since the electromagnetic wave generator can emit high-frequency electromagnetic waves to bombard the metal surface, it can promote the shedding of the oxide layer, which is beneficial to the cleaning and activation of the metal surface, and can effectively reduce welding defects such as pores or cracks, and is particularly suitable for resistance spot welding of aluminum body structures.

[0017] Other advantages, objectives, and features of the present invention will be described in detail in the following description and, to some extent, will be apparent to those skilled in the art upon examination and study of the following or may be learned from practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the local structure of the utility model

[0019] Figure 2 This is a schematic diagram of the overall structure of the utility model

[0020] Figure 3 This is a schematic diagram of the installation structure of the electromagnetic wave generator of this utility model

[0021] Figure numerals: 1-spot welding robot body; 101-upper electrode rod; 2-mounting module; 201-connecting rod; 201a-upper connecting rod; 201b-lower connecting rod; 202-driving assembly; 202a-mounting seat; 202b-telescopic cylinder; 203-protective tube; 204-limiting guide; 204a-guide hole; 3-preheating module; 301-electromagnetic wave generator; 302-infrared temperature probe; 4-workpiece to be welded. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only used to illustrate the basic concept of the present invention. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0023] See also Figure 1-3 The present embodiment discloses a pretreatment device for adhesive resistance spot welding, comprising: a mounting module 2, which is arranged on a spot welding robot body 1. The mounting module 2 is used to provide a mounting position for a preheating module 3. The structure of the mounting module 2 is not limited. Usually, the mounting module 2 is arranged on the welding clamp of the spot welding robot body 1; a preheating module 3, which includes an electromagnetic wave generator 301 arranged on the mounting module 1. The electromagnetic wave generator 301 is used to complete preheating of the workpiece 4 to be welded. The electromagnetic wave generator 301 can be of various types, such as an infrared generator or a laser generator. The electromagnetic wave generator 301 emits electromagnetic waves to achieve non-contact rapid preheating of the workpiece;

[0024] In the above structural design, by adding a preheating module using an electromagnetic wave generator 301 to the spot welding robot body 1, the preheating of the welding point area of ​​the workpiece 4 to be welded can be completed quickly, thereby improving the fluidity of the structural adhesive, ensuring the complete extrusion of the structural adhesive, and reducing the frequency of explosion points or burn-throughs in resistance spot welding of adhesive joints; at the same time, since the electromagnetic wave generator can emit high-frequency electromagnetic waves to bombard the metal surface to promote the shedding of the oxide layer, it is beneficial to the cleaning and activation of the metal surface, and can effectively reduce welding defects such as pores or cracks, and is especially suitable for resistance spot welding of aluminum body structures; of course, by setting the mounting module 2 on the spot welding robot body 1, it can move along the set trajectory of the robot to ensure that the preheating module 3 completes the heating of different welding points.

[0025] In this embodiment, the electromagnetic wave generator 301 is an infrared generator or a laser generator. The infrared generator or the laser generator has a fast heating speed, good heating uniformity of the object, and a long service life.

[0026] In this embodiment, the electromagnetic wave generator 301 is rotatably mounted on the mounting module in a lockable manner. This mounting method facilitates adjustment of the mounting angle of the electromagnetic wave generator 301 and facilitates focusing during debugging.

[0027] In this embodiment, the mounting module 2 includes a connecting rod 201 and a driving assembly 202 fixedly mounted on the spot welding robot body 1. The connecting rod 201 is connected to the driving assembly 202 and can move axially under the drive of the driving assembly 202. The electromagnetic wave generator 301 is arranged at the lower end of the connecting rod 201. Here, the driving assembly 202 preferably adopts a cylinder. Of course, in other embodiments, hydraulic cylinders, electric cylinders, etc. can also be used as needed, as long as they can drive the connecting rod 201 to move axially. Here, the connecting rod 201 preferably adopts a cylindrical Rod, of course, other shapes of rods can also be used in other implementations; in this structural design, the installation of the electromagnetic wave generator 301 is completed by using the connecting rod 201, and the overall space occupied is small. At the same time, since the connecting rod 201 can be driven to move axially, it is beneficial to improve the passability of the overall structure, especially in the body structure welding process, after the connecting rod 201 is retracted, the electromagnetic wave generator 301 can be avoided from interfering with the body structure. After the welding end of the robot moves into place, the connecting rod 201 is lowered to ensure that the electromagnetic wave generator 301 heats the corresponding part.

[0028] In this embodiment, the driving assembly 202 includes a mounting base 202a fixedly connected to the spot welding robot body 1 and a telescopic cylinder 202b fixedly mounted on the mounting base 202a, and the upper end of the connecting rod 201 is fixedly connected to the working end of the telescopic cylinder 202b; it can be understood that the "upper end" of the connecting rod 201 here refers to the upper end of the connecting rod 201 based on the attachment. Figure 1The upper end in the up and down directions; specifically, the mounting seat 202a here is a mounting plate structure, which can be fixedly installed on the spot welding robot body 1 by bolts, such as the mounting seat 202a can be installed on the skeleton of the welding robot body 1, and the specific position is adaptively arranged according to needs; the telescopic cylinder 202b here can also be fixedly installed on the mounting seat 202a by bolts, and the connecting rod 201 and the working end of the telescopic cylinder 202b can also be connected by bolts, and the working end of the telescopic cylinder 202b is the telescopic end of the telescopic cylinder 202b; in this structural design, the telescopic cylinder 202b is used to drive the movement of the connecting rod 201, and the action is fast, which is conducive to ensuring work efficiency. At the same time, the cost of the telescopic cylinder 202b is relatively low, and the installation structure is simple, which is conducive to reducing costs.

[0029] In this embodiment, a protective tube 203 is provided at the lower end of the connecting rod 201, and the electromagnetic wave generator 301 is fixed in the protective tube 203. The fixing method of the electromagnetic wave generator 301 and the protective tube 203 is not limited, and is selected according to the selected electromagnetic wave generator 301, such as bolt connection. In this structural design, by designing the protective tube 203 and installing the electromagnetic wave generator 301 in the protective tube 203, it is beneficial to form protection for the electromagnetic wave generator 301 and prevent the electromagnetic wave generator 301 from being damaged by collision during debugging and operation. In addition, end plates are respectively provided at both ends of the protective tube 203, and openings are provided on both end plates to The cables for the electromagnetic wave generator 301 and the emitted electromagnetic waves pass through; the protective tube 203 is rotatably installed on the connecting rod 201 in a lockable manner. Specifically, the protective tube 203 is connected to the connecting rod 201 through a rotating shaft and is locked by bolts; this structural design is conducive to adjusting the emission angle of the electromagnetic wave generator 301, and can be used in conjunction with the axial position adjustment of the connecting rod 201, which is conducive to focusing during debugging, improves the adaptability of the overall structure, and is conducive to completing the welding preheating of sheet metals of different thicknesses; the protective tube 203 is a metal tube, such as a stainless steel tube, etc. The metal tube has good strength, high durability, and good high temperature resistance.

[0030] In this embodiment, the preheating module 3 also includes an infrared temperature measuring probe 302 and a controller (not shown in the figure). The infrared temperature measuring probe 302 is fixedly installed on the outer peripheral surface of the protective tube 203 to detect the temperature of the welding point area, and the controller is connected to the infrared temperature measuring probe 302; specifically, the infrared temperature measuring probe 302 can be installed with the protective tube 203 by means of snap connection, screw connection, etc.; the infrared temperature measuring probe 302 and the controller are generally electrically connected, and the controller can be a thermostat, etc.; during use, the infrared temperature measuring probe 302 monitors the temperature of the welding point area of ​​the workpiece 4 to be welded in real time, and converts the collected temperature into an electrical signal and transmits it to the controller. When the temperature reaches the set preheating temperature, the controller issues an instruction to perform welding action; in this structural design, by setting the infrared temperature measuring probe 302 and the controller, it is possible to accurately determine whether the preheating temperature meets the standard, which is conducive to further improving the welding quality.

[0031] In this embodiment, the connecting rod 201 is arranged in parallel with the upper electrode rod 101 of the spot welding robot. The arrangement structure is reasonable and compact, which is conducive to further reducing the arrangement space of the overall structure and improving the passability.

[0032] In this embodiment, the mounting module 2 also includes a limiting guide 204 fixedly mounted on the spot welding robot body 1, and a guide hole 204a is provided on the limiting guide 204, and the connecting rod 201 is slidably fitted in the guide hole 204a; specifically, the limiting guide 204 is fixedly mounted on the arm sleeve outside the electrode rod 101 of the spot welding robot by screws; a bushing or linear bearing can be provided in the guide hole 204a as needed to reduce the friction force of the mating part with the connecting rod 201; in this structural design, by providing the limiting guide 204, it is beneficial to improve the operating stability of the connecting rod 201 and reduce the fluctuation of the connecting rod 201 during operation, which is particularly suitable for the case where the connecting rod 201 is longer; of course, multiple groups of limiting guides 204 can be provided as needed, such as two groups spaced along the length direction of the connecting rod 201 here.

[0033] In this embodiment, the connecting rod 201 includes an upper connecting rod 201a and a lower connecting rod 201b detachably connected to the lower end of the upper connecting rod 201a, and the electromagnetic wave generator 301 is arranged at the lower end of the lower connecting rod 201b; specifically, the upper connecting rod 201a and the lower connecting rod 201b are connected by threads; this structural design is conducive to later disassembly and maintenance. The electromagnetic wave generator 301 and the lower connecting rod 201b can be disassembled by simply removing the lower connecting rod 201b, which is convenient for installation.

[0034] When welding using a spot welding robot equipped with the above-mentioned adhesive resistance spot welding pretreatment device, the welding can be carried out in the following steps:

[0035] S1: Radiation heating stage: When the robot moves to the spot welding position, the electromagnetic wave generator 301 irradiates the annular area to be spot welded. When the heating temperature reaches the set temperature value, the controller outputs a signal to start the robot to start welding. Conversely, if the heating temperature does not reach the set temperature value, the controller controls the electromagnetic wave generator 301 to continue heating until the heating temperature reaches the set temperature. During the heating process, the heat inside the workpiece 4 to be welded will be transferred to the structural adhesive for uniform heating, thereby improving the fluidity of the structural adhesive. At the same time, high-frequency electromagnetic waves bombard the surface of the workpiece 4 to be welded to peel off the oxide layer, promoting the shedding of the oxide layer and cleaning and activating the surface of the workpiece 4 to be welded.

[0036] S2: Pre-compression stage: pressure F>0, current I=0, pre-compression pressure is applied;

[0037] S3: Transition stage: pressure F>0, current I=0, electrode pressure gradually increases from pre-pressing pressure to preheating pressure, and the preheating pressure is selected as 3-5KN;

[0038] S4: Current slow rise stage: pressure F>0, current I>0, during this process the electrode pressure remains unchanged at the preheating pressure, and after the transition stage the starting current rises to the preheating current;

[0039] S5: Preheating stage: pressure F>0, current I>0, the electrode pressure maintains the preheating pressure unchanged, and a preheating current is added for preheating. The preheating current is selected as 12-15KA, and the preheating time is selected as 50-120ms;

[0040] S6: Cooling stage: pressure F>0, current I=0, continue to maintain the electrode pressure at the preheating pressure, the current drops rapidly to 0, and the cooling time is selected as 5-10ms;

[0041] S7: Welding stage: pressure F>0, current I>0, electrode pressure is increased to welding pressure, current is welding current, current is selected as 25-30kN, welding pressure is selected as 5-7kN, welding time is selected as 60-100ms, and the aluminum alloy plate is heated to the melting point to form a molten nugget under the resistance heating effect;

[0042] S8: Holding stage: pressure F>0, current I=0, after the welding current is cut off, the welding pressure remains unchanged, the cooling time is selected from 5-40ms, the molten core is maintained under the electrode pressure for a period of time to cool and crystallize. Due to the fast energy dissipation at the edge of the molten core, crystallization begins first and spreads to the central area until the molten core is completely formed;

[0043] S9: Rest stage: pressure F = 0, current I = 0, welding current value and electrode pressure value are both 0, the electrode begins to rise back to the original position and waits for the start of the next welding cycle.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A pretreatment device for adhesive resistance spot welding, characterized in that: include: A mounting module (2) is arranged on the spot welding robot body (1); A preheating module (3) includes an electromagnetic wave generator (301) arranged on the mounting module (2), and the electromagnetic wave generator (301) is used to complete preheating of a workpiece (4) to be welded.

2. The adhesive resistance spot welding pretreatment device according to claim 1, characterized in that: The electromagnetic wave generator (301) is an infrared generator or a laser generator.

3. The adhesive resistance spot welding pretreatment device according to claim 2, characterized in that: The electromagnetic wave generator (301) is rotatably mounted on the mounting module (2) in a lockable manner.

4. The adhesive resistance spot welding pretreatment device according to any one of claims 1 to 3, characterized in that: The mounting module (2) comprises a connecting rod (201) and a driving assembly (202) fixedly mounted on a spot welding robot body (1); the connecting rod (201) is connected to the driving assembly (202) and can move axially under the drive of the driving assembly (202); and the electromagnetic wave generator (301) is arranged at the lower end of the connecting rod (201).

5. The adhesive resistance spot welding pretreatment device according to claim 4, characterized in that: The driving assembly (202) comprises a mounting seat (202a) fixedly connected to the spot welding robot body (1) and a telescopic cylinder (202b) fixedly mounted on the mounting seat (202a); the upper end of the connecting rod (201) is fixedly connected to the working end of the telescopic cylinder (202b).

6. The adhesive resistance spot welding pretreatment device according to claim 4, characterized in that: A protective tube (203) is provided at the lower end of the connecting rod (201), the electromagnetic wave generator (301) is fixed in the protective tube (203), and the protective tube (203) is rotatably mounted on the connecting rod (201) in a lockable manner; the protective tube (203) is a metal protective tube.

7. The adhesive resistance spot welding pretreatment device according to claim 6, characterized in that: The preheating module (3) further comprises an infrared temperature measuring probe (302) and a controller. The infrared temperature measuring probe (302) is fixedly mounted on the outer peripheral surface of the protective tube (203) for detecting the temperature of the soldering point area. The controller is connected to the infrared temperature measuring probe (302).

8. The adhesive resistance spot welding pretreatment device according to claim 4, characterized in that: The connecting rod (201) is arranged in parallel with the upper electrode rod (101) of the spot welding robot.

9. The adhesive resistance spot welding pretreatment device according to claim 4, characterized in that: The mounting module (2) further comprises a position limiting guide member (204) fixedly mounted on the spot welding robot body (1); a guide hole (204a) is provided on the position limiting guide member (204); and the connecting rod (201) is slidably mounted in the guide hole (204a).

10. The adhesive resistance spot welding pretreatment device according to claim 9, characterized in that: The connecting rod (201) comprises an upper connecting rod (201a) and a lower connecting rod (201b) detachably connected to the lower end of the upper connecting rod (201a), and the electromagnetic wave generator (301) is arranged at the lower end of the lower connecting rod (201b).

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