Automatic electric arc welding robot

Abstract

The invention belongs to the field of electric arc welding, and particularly relates to an automatic electric arc welding robot which comprises a robot body and a welding gun, the welding gun comprises a gun barrel and an elbow section, and the gun barrel is sleeved with a high-frequency vibration disc assembly used for applying multi-frequency-domain high-frequency vibration to the welding gun. The automatic electric arc welding robot can conduct automatic welding, the welding angle is flexible and changeable, and the automatic electric arc welding robot is particularly suitable for automatic welding of non-standard automobile accessories such as automobile seats and cushions; by additionally arranging the high-frequency vibration disc assembly, welding fluid generated during welding can be better, more uniformly and deeper distributed at a welding seam by means of multi-frequency-domain high-frequency vibration, so that the welding quality is remarkably improved, even if a welding seam gap is enlarged, the welding quality problem cannot occur, and hidden cracks, dense bubble areas and heat treatment cracks cannot occur in the welding seam.

Description

Technical Field

[0001] The invention belongs to the technical field of arc welding, and in particular relates to an automatic arc welding robot. Background Art

[0002] In the field of automotive parts, such as car seats, cushions and other auto parts, their skeleton structures are usually non-standard and generally rely on welding robots for welding.

[0003] Also because of non-standard parts, when assembling frame-related parts, there will be some areas where the weld gap is far beyond the normal area. The weld gap refers to the distance between welded parts, and a suitable gap can ensure the welding quality. For example, a gap that is too large may lead to insufficient welding strength, while a gap that is too small may lead to a cold weld. In general, the weld gap should be controlled between 0.03 and 0.15 mm. However, for the frames of car seats and cushions, the weld gap often exceeds 0.2 mm. The weld gap is too large, and the existing welding machines and welding processes are prone to a large number of poor welding, including but not limited to the following poor welding:

[0004] 1) After welding is completed, no cracks are found on the weld surface; after being placed at room temperature for 1 to 3 days, cracks appear; this type of crack can be defined as hidden cracks.

[0005] 2) After welding is completed, there is a certain probability that a dense bubble area will appear on the weld surface (the number of bubbles per square centimeter exceeds 1.6), while there are no bubbles in other areas.

[0006] 3) After welding was completed, no cracks were found on the weld surface; after baking at 60°C for 10 minutes, cracks appeared; this type of crack can be defined as heat treatment cracks.

[0007] The mold temperature of polyurethane foaming is generally controlled above 60℃, and the foaming time is generally above 10 minutes. Therefore, if the frame with the above welding defects is placed in a high pressure environment (the pressure of the polyurethane high pressure foaming machine is generally greater than 5MPa), the weld quality of the frame may be further degraded, resulting in serious quality defects in the product.

[0008] The most direct way to solve the above welding defects is to make a large number of corresponding fixtures to reduce the weld gap during welding. However, since it is a non-standard part, the installation and disassembly of the angle is difficult. Each frame needs to be installed with a fixture. In addition, the fixture will interfere with the continuity of welding, resulting in the inability to improve welding efficiency.

[0009] Based on this, the present invention is proposed. Summary of the invention

[0010] The object of the present invention is to provide an automatic arc welding robot to solve the above-mentioned problems.

[0011] An automatic arc welding robot comprises a robot body and a welding gun, wherein the robot body is provided with a mechanical arm, the welding gun comprises a gun rod and an elbow section, and the outer sleeve of the gun rod is provided with a high-frequency vibration disk assembly for applying multi-frequency domain high-frequency vibration to the welding gun.

[0012] As a further improvement, the high-frequency vibration disk assembly includes a round box, the gun rod is embedded in the center of the round box and the gun rod and the round box are sealed at the connection, and a heat exchange cavity is formed between the inner wall of the round box and the outer wall of the gun rod;

[0013] A plurality of piezoelectric ceramic blocks are arranged inside the heat exchange cavity, one end of the piezoelectric ceramic block is fixedly connected to the gun rod, and a gap is arranged between the other end of the piezoelectric ceramic block and the inner wall of the round box.

[0014] As a further improvement, there are five piezoelectric ceramic blocks, which are asymmetrically arranged outside the gun barrel and have different lengths.

[0015] As a further improvement, the five piezoelectric ceramic blocks are marked as the first piezoelectric ceramic block, the second piezoelectric ceramic block, the third piezoelectric ceramic block, the fourth piezoelectric ceramic block, and the fifth piezoelectric ceramic block in a clockwise direction, respectively. The angle between the length direction of the first piezoelectric ceramic block and the length direction of the second piezoelectric ceramic block is β, the angle between the length direction of the second piezoelectric ceramic block and the length direction of the third piezoelectric ceramic block is γ, the angle between the length direction of the third piezoelectric ceramic block and the length direction of the fourth piezoelectric ceramic block is ζ, and the angle between the length direction of the fifth piezoelectric ceramic block and the length direction of the first piezoelectric ceramic block is θ, β+γ+δ+ζ+θ=360°, β+40°=γ, γ+10°=δ, ζ+20°=δ, ζ=θ.

[0016] Further improvement, β=42°, γ=82°, δ=92°, ζ=72°, θ=72°.

[0017] As a further improvement, the length of the first piezoelectric ceramic block is a, the length of the second piezoelectric ceramic block is b, the length of the third piezoelectric ceramic block is c, the length of the fourth piezoelectric ceramic block is d, and the length of the fifth piezoelectric ceramic block is e, a=2c, b=3c, d=2c, and e=2.6c.

[0018] As a further improvement, the resonant frequency of the first piezoelectric ceramic block is f1, the resonant frequency of the second piezoelectric ceramic block is f2, the resonant frequency of the third piezoelectric ceramic block is f3, the resonant frequency of the fourth piezoelectric ceramic block is f4, and the resonant frequency of the fifth piezoelectric ceramic block is f5, f2=f4, f3 / f1>10, f5 / f3>10.

[0019] Further improvement, f1 = 0.8kHz, f2 = 20kHz, f3 = 12kHz, f4 = 20kHz, f5 = 136kHz.

[0020] As a further improvement, the outside of the round box is connected to two water pipes, and both water pipes are connected to the heat exchange cavity.

[0021] As a further improvement, the angle between the gun rod and the elbow section is an obtuse angle.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The automatic arc welding robot described in the present invention can perform automated welding with flexible and changeable welding angles, and is particularly suitable for automated welding of non-standard automotive accessories such as car seats and cushions. By adding a high-frequency vibration disk assembly, the welding liquid generated during welding can be better, more evenly, and more deeply distributed in the weld with the aid of multi-frequency domain high-frequency vibration, thereby significantly improving the welding quality. Even if the weld gap reaches 0.2 to 0.43 mm, there will be no welding quality problems, and the weld will not have hidden cracks, dense bubble areas, and heat treatment cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of the automatic arc welding robot of the present invention;

[0025] Figure 2 It is a structural schematic diagram of the high-frequency vibration disk assembly of the present invention;

[0026] Figure 3 This is a photo of the dense bubble area appearing in the weld. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0028] In the description of the present invention, it should be noted that, unless otherwise specified, "multiple" means two or more than two; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Example 1

[0031] like Figure 1 As shown, the automatic arc welding robot comprises a robot body 10 and a welding gun, wherein the robot body 10 is provided with a mechanical arm 11, and the welding gun comprises a gun rod 21 and an elbow section 22. The gun rod 21 is externally sleeved with a high-frequency vibration disk assembly 30 for applying multi-frequency high-frequency vibration to the welding gun.

[0032] For the skeleton welding of automobile accessories such as automobile seats and cushions, the automatic arc welding robot is used for welding, which has a higher degree of automation and high welding efficiency, and is particularly suitable for non-standard parts; wherein the robot body 10 is preferably a three-axis robot or a five-axis robot.

[0033] The bending design of the gun rod 21 and the elbow section 22, especially the obtuse angle between the gun rod 21 and the elbow section 22, is mainly to adapt to different welding positions and angles, reduce wire feeding resistance, improve welding quality, and meet the requirements of mechanical durability and heat concentration. This design enables the welding gun to maintain high efficiency and stable performance in various complex environments.

[0034] In the present invention, the high-frequency vibration disk assembly 30 can generate multi-domain high-frequency vibrations (amplitude of 5 to 80 μm), so that the welding gun can be driven by the multi-domain high-frequency vibrations. The welding liquid generated during welding can be better, more evenly and more deeply distributed in the weld with the help of multi-domain high-frequency vibrations, thereby significantly improving the welding quality. Even if the weld gap reaches 0.2 to 0.43 mm (far exceeding the conventional weld gap, the conventional weld gap is 0.03 to 0.15 mm), the welding quality is high, and the weld will not have hidden cracks, dense bubble areas and heat treatment cracks.

[0035] Example 2

[0036] In Example 1, Figure 2 As shown, the high-frequency vibration disk assembly 30 includes a round box 31, the gun rod 21 is embedded in the center of the round box 31, and the gun rod 21 and the round box 31 are sealed at the connection, and a heat exchange cavity 32 is formed between the inner wall of the round box 31 and the outer wall of the gun rod 21;

[0037] A plurality of piezoelectric ceramic blocks are disposed inside the heat exchange cavity 32 , one end of each piezoelectric ceramic block is fixedly connected to the gun rod 21 , and a gap is disposed between the other end of each piezoelectric ceramic block and the inner wall of the round box 31 .

[0038] In this embodiment, preferably, there are five piezoelectric ceramic blocks, which are asymmetrically arranged outside the gun barrel 21 and have different lengths.

[0039] The five piezoelectric ceramic blocks are marked as the first piezoelectric ceramic block 51, the second piezoelectric ceramic block 52, the third piezoelectric ceramic block 53, the fourth piezoelectric ceramic block 54, and the fifth piezoelectric ceramic block 55 in clockwise direction. The angle between the length direction of the first piezoelectric ceramic block 51 and the length direction of the second piezoelectric ceramic block 52 is β, the angle between the length direction of the second piezoelectric ceramic block 52 and the length direction of the third piezoelectric ceramic block 53 is γ, the angle between the length direction of the third piezoelectric ceramic block 53 and the length direction of the fourth piezoelectric ceramic block 54 is δ, the angle between the length direction of the fourth piezoelectric ceramic block 54 and the length direction of the fifth piezoelectric ceramic block 55 is ζ, and the angle between the length direction of the fifth piezoelectric ceramic block 55 and the length direction of the first piezoelectric ceramic block 51 is θ, β+γ+δ+ζ+θ=360°, β+40°=γ, γ+10°=δ, ζ+20°=δ, ζ=θ.

[0040] Among them, preferably, β=42°, γ=82°, δ=92°, ζ=72°, and θ=72°.

[0041] The length of the first piezoelectric ceramic block 51 is a, the length of the second piezoelectric ceramic block 52 is b, the length of the third piezoelectric ceramic block 53 is c, the length of the fourth piezoelectric ceramic block 54 is d, and the length of the fifth piezoelectric ceramic block 55 is e, a=2c, b=3c, d=2c, and e=2.6c.

[0042] The resonant frequency of the first piezoelectric ceramic block 51 is f1, the resonant frequency of the second piezoelectric ceramic block 52 is f2, the resonant frequency of the third piezoelectric ceramic block 53 is f3, the resonant frequency of the fourth piezoelectric ceramic block 54 is f4, and the resonant frequency of the fifth piezoelectric ceramic block 55 is f5, f2=f4, f3 / f1>10, f5 / f3>10.

[0043] Among them, preferably, f1=0.8kHz, f2=20kHz, f3=12kHz, f4=20kHz, and f5=136kHz.

[0044] Example 3

[0045] Compared with Example 2, in this example, the high-frequency vibration disk assembly 30 is not started, and the rest is the same.

[0046] Example 4

[0047] Compared with Example 2, the welding gun in this example is not provided with an elbow section 22, but only has a gun rod 21, and the rest is the same.

[0048] Weld quality characterization test

[0049] Carbon structural steel was used as the welded part. The cumulative length of the weld was 3m for each welding test. After welding, the weld surface was immediately observed for conventional cracks (observed within 1h after welding), hidden cracks, dense bubble areas, and heat treatment cracks. The distribution density of hidden cracks (pieces / dm), dense bubble area distribution density (pieces / m), and heat treatment crack distribution density (pieces / dm) were calculated in turn. The test results of Examples 2 to 4 are shown in Table 1:

[0050] Table 1

[0051]

[0052] As can be seen from Table 1, by setting the high-frequency vibration disk assembly 30, for a "bend"-shaped welding gun, the dense bubbles when the weld gap is large can be significantly reduced. Figure 3In a small area, a large number of dense pores appeared. If it is a "straight tube" welding gun, even if the weld gap is small (0.25mm, still larger than the conventional weld gap of 0.15mm), although the distribution density of the dense bubble area is 0 / m, there are still more than 16 single bubbles (no bubble enrichment).

[0053] Example 5

[0054] Compared with Example 2, only the values ​​of β, γ, δ, ζ, and θ are changed in this example, and the rest are the same. The corresponding number of conventional cracks is 0. When the weld gap is 0.43 mm, the test results of the corresponding hidden crack distribution density, dense bubble area distribution density, and heat treatment crack distribution density are shown in Tables 2 and 3:

[0055] Table 2

[0056]

[0057]

[0058] In Table 2, β=0 means that the first piezoelectric ceramic block 51 and the second piezoelectric ceramic block 52 are in contact and closely attached.

[0059] Table 3

[0060]

[0061] It can be seen from Table 3 that the distribution positions of the five piezoelectric ceramic blocks (changes in β, γ, δ, ζ, and θ) mainly affect the number of hidden cracks in the weld, and have little effect on dense bubbles, heat treatment cracks, etc.

[0062] Example 6

[0063] Compared with Example 2, only the ratios of a, b, c, d, and e are changed in this example, and the rest are the same. The corresponding number of conventional cracks is 0. When the weld gap is 0.43 mm, the test results of the corresponding hidden crack distribution density, dense bubble area distribution density, and heat treatment crack distribution density are shown in Table 4:

[0064] Table 4

[0065]

[0066] It can be seen from Table 4 that the length changes of the five piezoelectric ceramic blocks (a, b, c, d, e) mainly affect the heat treatment cracks of the weld, and have little effect on the number of hidden cracks and dense bubbles.

[0067] Example 7

[0068] Compared with Example 2, only f1, f2, f3, f4, and f5 are changed in this example, and the rest are the same. The corresponding number of conventional cracks is 0. When the weld gap is 0.43 mm, the test results of the corresponding hidden crack distribution density, dense bubble area distribution density, and heat treatment crack distribution density are shown in Table 5:

[0069] Table 5

[0070]

[0071] It can be seen from Table 5 that the change of the resonant frequency of the five piezoelectric ceramic blocks will significantly affect the vibration effect, especially the distribution of dense bubble areas, and the impact on hidden cracks and heat treatment cracks is second.

[0072] Example 8

[0073] Compared with Example 2, in this example, if the number of piezoelectric ceramic blocks is less than five, no matter how their length, distribution angle and resonant frequency are adjusted, it is found that according to the weld quality characterization test, the corresponding number of conventional cracks is at least 8; therefore, the preferred number of piezoelectric ceramic blocks is five.

[0074] Example 9

[0075] To prevent overheating, the outside of the round box 31 is connected to two water pipes, both of which are connected to the heat exchange chamber 32. One of the water pipes is fed with cooling water, and the other water pipe is refluxed.

[0076] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An automatic arc welding robot, comprising a robot body (10) and a welding gun, wherein the robot body (10) is provided with a mechanical arm (11), and the welding gun comprises a gun rod (21) and an elbow section (22), characterized in that: The gun rod (21) is externally sleeved with a high-frequency vibration disk assembly (30) for applying multi-frequency high-frequency vibration to the welding gun.

2. An automatic arc welding robot according to claim 1, characterized in that: The high-frequency vibration disk assembly (30) comprises a round box (31), the gun rod (21) is embedded in the center of the round box (31), and the gun rod (21) and the round box (31) are sealed at the connection point, and a heat exchange cavity (32) is formed between the inner wall of the round box (31) and the outer wall of the gun rod (21); A plurality of piezoelectric ceramic blocks are arranged inside the heat exchange cavity (32), one end of each piezoelectric ceramic block is fixedly connected to the gun rod (21), and a gap is arranged between the other end of each piezoelectric ceramic block and the inner wall of the round box (31).

3. An automatic arc welding robot according to claim 2, characterized in that: There are five piezoelectric ceramic blocks, which are asymmetrically arranged outside the gun rod (21) and have different lengths.

4. The automatic arc welding robot according to claim 3, characterized in that: The five piezoelectric ceramic blocks are marked as a first piezoelectric ceramic block (51), a second piezoelectric ceramic block (52), a third piezoelectric ceramic block (53), a fourth piezoelectric ceramic block (54), and a fifth piezoelectric ceramic block (55) in a clockwise direction. The angle between the length direction of the first piezoelectric ceramic block (51) and the length direction of the second piezoelectric ceramic block (52) is β, the angle between the length direction of the second piezoelectric ceramic block (52) and the length direction of the third piezoelectric ceramic block (53) is γ, and the The angle between the length direction of the third piezoelectric ceramic block (53) and the length direction of the fourth piezoelectric ceramic block (54) is δ, the angle between the length direction of the fourth piezoelectric ceramic block (54) and the length direction of the fifth piezoelectric ceramic block (55) is ζ, and the angle between the length direction of the fifth piezoelectric ceramic block (55) and the length direction of the first piezoelectric ceramic block (51) is θ, β+γ+δ+ζ+θ=360°, β+40°=γ, γ+10°=δ, ζ+20°=δ, ζ=θ.

5. The automatic arc welding robot according to claim 4, characterized in that: β=42°, γ=82°, δ=92°, ζ=72°, θ=72°.

6. The automatic arc welding robot according to claim 4, characterized in that: The length of the first piezoelectric ceramic block (51) is a, the length of the second piezoelectric ceramic block (52) is b, the length of the third piezoelectric ceramic block (53) is c, the length of the fourth piezoelectric ceramic block (54) is d, and the length of the fifth piezoelectric ceramic block (55) is e, a=2c, b=3c, d=2c, and e=2.6c.

7. An automatic arc welding robot according to claim 6, characterized in that: The resonance frequency of the first piezoelectric ceramic block (51) is f1, the resonance frequency of the second piezoelectric ceramic block (52) is f2, the resonance frequency of the third piezoelectric ceramic block (53) is f3, the resonance frequency of the fourth piezoelectric ceramic block (54) is f4, and the resonance frequency of the fifth piezoelectric ceramic block (55) is f5, f2=f4, f3 / f1>10, and f5 / f3>10.

8. The automatic arc welding robot according to claim 7, characterized in that: f1=0.8kHz, f2=20kHz, f3=12kHz, f4=20kHz, f5=136kHz.

9. The automatic arc welding robot according to claim 2, characterized in that: The outside of the round box (31) is connected to two water pipes, and both water pipes are in communication with the heat exchange chamber (32).

10. The automatic arc welding robot according to claim 1, characterized in that: The angle between the gun rod (21) and the elbow section (22) is an obtuse angle.

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