Electrode tip for welding

Abstract

The present invention relates to a welding electrode tip. A molybdenum alloy shell 20 having a second center hole 21 with a smaller diameter than a first center hole 11 is threadedly coupled to the end of a copper alloy adapter 10 having the first center hole 11. The adapter 10 and the shell 20 are screwed together with a large torque, thereby causing plastic deformation of the thread to perform caulking fixation. The second center hole 21 is formed to have a length of 1 / 3 or less of the length of the first center hole 11, so that welding current is concentrated on the inner surface of the second center hole 21 and flows through a welding wire. Clogging of the welding wire is difficult to occur, deviation of the welding current is difficult to occur, and the service life can be greatly extended.

Description

Technical Field

[0001] This invention relates to a welding conductive nozzle for arc welding. Background Technology

[0002] The welding contact tip for arc welding is a component that is installed at the end of the welding torch of the welding machine and has the function of guiding the welding wire fed through the welding torch toward the welding position while supplying welding current to the welding wire.

[0003] Traditional welding contact tips are typically like Figure 5 As shown, a central hole 2 of constant diameter is formed inside the copper alloy body 1. The welding wire is held by rollers and fed in from the base end of the contact tip. Therefore, if the gap between the inner diameter of the central hole 2 and the outer diameter of the welding wire is small, the contact resistance with the inner surface of the central hole 2 increases, potentially causing the welding wire to become clogged inside and not be smoothly extruded. Therefore, for example, when the outer diameter of the welding wire is 1.2 mm, the inner diameter of the central hole 2 is usually increased to about 1.5 mm to form a welding contact tip with sufficient clearance. However, increasing the clearance in this way presents the following problem: the contact between the inner surface of the central hole 2 and the welding wire becomes unstable, and the welding current is prone to deviation.

[0004] Furthermore, the total length of the welding contact tip is 40mm or 45mm depending on the welding machine specifications, making it difficult to accurately penetrate the relatively narrow center hole 2, which has an inner diameter of 1.5mm throughout its entire length. If the center hole 2 is slightly bent or eccentric, the welding wire is prone to clogging, which in turn can cause deviations in the welding current.

[0005] As mentioned above, if the gap of the conventional welding contact tip is increased to prevent clogging of the welding wire, it can easily lead to deviations in the welding current. Furthermore, there is a significant problem of the diameter of the central hole 2 gradually increasing due to wear and tear from contact with the welding wire. In particular, the end of the central hole 2 near the welding position is subjected to high heat from the electric arc, causing the diameter to easily enlarge. This, in turn, can sometimes lead to incorrect welding position due to misdirection of the welding wire feed. Therefore, it has been necessary to interrupt welding operations at specified intervals to replace the welding contact tip with a new one, resulting in decreased welding efficiency and increased welding costs.

[0006] To address this issue, in patent document 1, such as Figure 6As shown, a welding conductive tip made of hard metal or ceramic is described, with its end head 3 embedded in the end portion of a central hole 2. This welding conductive tip is expected to prevent the diameter of the end portion from enlarging; however, if the diameter of the central hole 4 of the end head 3 is kept constant while the diameter of the central hole 2 of the main body 1 is enlarged, a step difference will be created at the connection point with respect to the end head 3, causing blockage. Furthermore, regarding this… Figure 6 Even if the gap of the central hole 2 is increased to prevent clogging, the problem of welding current deviation cannot be solved by using a conductive tip with a specific structure. Furthermore, it also increases the manufacturing cost of the welding conductive tip.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Utility Model Application Publication No. 64-15674 Summary of the Invention

[0010] Therefore, the object of the present invention is to eliminate the above-mentioned existing problems and provide a welding conductive tip that is less prone to clogging of welding wires, less prone to deviation of welding current, and significantly extends the continuous use time (service life).

[0011] The present invention, completed to solve the above-mentioned problems, is a welding conductive tip. A molybdenum alloy housing with a second central hole smaller in diameter than the first central hole is threadedly connected to the end of a copper alloy adapter having a first central hole. The invention is characterized in that the end of the first central hole and the base of the second central hole contact each other via a tapered bore, and the adapter and the housing are screwed together with a large torque, thereby causing plastic deformation of the thread teeth for seam fixing. The length of the second central hole is less than 1 / 3 of the length of the first central hole, allowing the welding current to concentrate and flow through the welding wire on the inner surface of the second central hole.

[0012] Preferably, the housing is made of a molybdenum alloy containing titanium, zirconium, carbon, and the remainder being molybdenum, and the adapter is made of a copper alloy containing chromium.

[0013] Preferably, the inner diameter of the second center hole is set in advance to be 0.08 to 0.12 mm larger than the outer diameter of the welding wire used.

[0014] Preferably, the total length of the adapter and the housing combined is 40-45 mm, and the length of the second central hole is 5-15 mm.

[0015] Invention Effects

[0016] The welding contact tip of the present invention is constructed as follows: a housing having a second central hole with a diameter smaller than the first central hole is attached to the end of an adapter having a first central hole, the length of which is set to be less than 1 / 3 of the length of the first central hole. This makes the shorter second central hole at the end a smaller diameter, allowing the welding current to concentrate and flow through the welding wire on its inner surface. Furthermore, if the longer first central hole is pre-set to have sufficient clearance as in existing products, the contact resistance with the welding wire is reduced, making clogging less likely.

[0017] Furthermore, the welding contact tip of the present invention is constructed such that the adapter and the housing are screwed together with a large torque, thereby causing plastic deformation of the thread teeth and achieving weld seam fixation. Conventional welding contact tips have been designed to allow for detachable screwing of the housing and the end of the adapter, offering the advantage that the housing can be removed and replaced when the aperture at the end is enlarged. However, to replace the housing, the shape of the thread teeth must be maintained; microscopically, the ventral surfaces of the external and internal threads are in point contact. Therefore, the path of the welding current supplied from the adapter through the housing at the end becomes unstable, leading to welding current deviation. In contrast, by causing plastic deformation of the thread teeth and achieving weld seam fixation as in the present invention, the external and internal threads form a reliable ground contact, thereby stabilizing the current flow path from the adapter to the housing and suppressing welding current deviation.

[0018] Furthermore, regarding the conductive tip for welding according to the present invention, the adapter and housing can be manufactured separately, thus shortening the length of their respective center holes and simplifying the manufacturing process. Additionally, the combination of the adapter and housing can be freely selected before seam fixing, allowing for easy manufacturing of structures with overall lengths of 40mm and 45mm, thereby reducing manufacturing costs.

[0019] Furthermore, if the housing of the welding conductive tip of the present invention is made of a molybdenum alloy containing titanium, zirconium, carbon and the remainder being molybdenum, and the adapter is made of a copper alloy containing chromium, the wear resistance is improved, and the service life of continuous use can reach more than 40 times that of existing products. By reducing the replacement frequency of the welding conductive tip, the work efficiency of welding operations can be improved. Attached Figure Description

[0020] Figure 1 This is a central longitudinal sectional view of the welding conductive tip according to the embodiment.

[0021] Figure 2 This is a partial cross-sectional view of the adapter.

[0022] Figure 3 This is a partial sectional view of the shell.

[0023] Figure 4 It is a diagram showing the dimensional relationships.

[0024] Figure 5 This is a cross-sectional view of an existing conductive nozzle.

[0025] Figure 6 This is a cross-sectional view of the conductive nozzle shown in Patent Document 1. Detailed Implementation

[0026] The preferred embodiments of the present invention will be described below.

[0027] Figure 1 This is a central longitudinal sectional view of the welding conductive tip according to the embodiment, where 10 is an adapter and 20 is the housing at its end. The adapter 10 has a first central hole 11, and the housing 20 has a second central hole 21.

[0028] like Figure 2 As shown, the adapter 10 has a narrow-diameter cylindrical portion 13 at the end of the cylindrical body 12, and an external thread 14 is formed on the outer periphery of the end. Additionally, an external thread 15 for mounting a welding contact tip to a welding torch of a welding machine is formed at the base end of the cylindrical body 12. Furthermore, a first central hole 11 is formed along the entire length of the adapter 10, and its rear end is a tapered, enlarged diameter portion 16, facilitating the insertion of welding wire into the first central hole 11.

[0029] like Figure 3 As shown, the housing 20 has a hollow cylindrical portion 22 behind the tapered main body 26 with a pointed front end. An internal thread 23, which engages with the external thread 14 of the adapter 10, is formed on the inner surface of the central portion of this cylindrical portion 22. A hole 24 with the same diameter as the inner diameter of the internal thread 23 is formed between the cylindrical portion 22 and the main body 26. A second central hole 21 with a diameter smaller than the first central hole 11 is formed in the main body 26 of the housing 20, and a tapered hole 25 is formed at its rear end. The taper angle of the tapered hole 25 is 30° in this embodiment.

[0030] The adapter 10 can be made of a chromium-containing copper alloy, such as chromium copper or zirconium chromium copper. The housing 20 can be made of a molybdenum alloy. In this embodiment, a molybdenum alloy called TZM, containing titanium, zirconium, carbon, and with the remainder being molybdenum, is used. This molybdenum alloy has a conductivity of IACS 22-25%, which is lower than that of copper alloys, but it is a hard material with an HRB of around 100 and a recrystallization temperature exceeding 1300°C, thus exhibiting excellent heat resistance. Therefore, the aperture at the end near the solder joint is difficult to enlarge, resulting in a service life several tens of times longer than conventional chromium copper contact tips.

[0031] The total length of the welding contact tip used in Japan is either 40mm or 45mm, depending on the specifications of the welding machine. Figure 4 As shown, in any case, the length of the second central hole 21 of the housing 20 is shorter than one-third of the length of the first central hole 11. Specifically, the length of the second central hole is in the range of 5 to 15 mm. In this way, by shortening the length of the second central hole 21 of the housing 20, it becomes easier to penetrate the narrow diameter of the second central hole 21, which is made of a hard material, molybdenum alloy. Therefore, the length of the first central hole 11 through which the adapter 10 penetrates reaches a maximum of 40 mm, but since the adapter 10 is made of a soft copper alloy, accurate drilling can be performed. Furthermore, if the length of the second central hole 21 is less than 5 mm, the contact distance with the welding wire is insufficient, and the welding current is unstable. Conversely, if it exceeds 15 mm, it is not easy to perform the drilling operation, and the energizing position from the second central hole 21 to the welding wire becomes unstable, and the effect of concentrating the welding current on the inner surface of the second central hole 21 to flow into the welding wire, which is a feature of the present invention, is reduced. Thus, the shortening of the length of the second central hole 21 of the molybdenum alloy housing 20 is a feature of the present invention.

[0032] like Figure 1 As shown, the adapter 10 and the housing 20 are integrated by screwing in the external thread 14 and the internal thread 23. The end of the first center hole 11 and the base of the second center hole 21 are in contact via a tapered bore 25. As before, considering the possibility of clogging, the diameter of the first center hole 11 of the adapter 10 is set to have sufficient clearance. In contrast, the clearance of the inner diameter of the second center hole 21 is very small.

[0033] Specifically, when the diameter of the welding wire is 1.2 mm, the diameter of the first center hole 11 of the adapter 10 is 1.5 mm, and the gap of the first center hole 11 is 0.3 mm in the diameter direction and 0.15 mm on one side. In contrast, the diameter of the second center hole 21 is 1.3 mm, and its gap is 0.1 mm in the diameter direction and 0.05 mm on one side, reduced to 1 / 3 of the gap of the first center hole 11. The absolute values ​​of these gaps vary depending on the diameter of the welding wire used; if the wire diameter increases, the gap also increases. However, in any case, it is preferable that the inner diameter of the second center hole 21 is 0.08 to 0.12 mm larger than the outer diameter of the welding wire used, and the gap on the plate side is set to 0.04 to 0.06 mm. If the gap of the second center hole 21 is smaller than this range, there is a risk of blockage; if it is larger than this range, the electrical conductivity may deviate.

[0034] Because the smaller gap of the second center hole 21 is continuous with the larger gap of the first center hole 11 at its end, the welding wire fed from the base of the adapter 10 is unlikely to come into contact with the inner surface of the first center hole 11 as it passes through its interior. However, when it passes through the smaller gap of the second center hole 21, it comes into contact with its inner surface, and the welding current flows in a concentrated manner. Thus, the second center hole 21 of the housing 20, which determines the energizing position from the contact tip to the welding wire, allows the welding current to flow in a concentrated manner through the inner surface of the second center hole 21 onto the welding wire. Therefore, deviations in the welding current are suppressed.

[0035] As described above, the welding conductive nozzle of the present invention integrates the external thread 14 of the adapter 10 with the internal thread 23 of the housing 20. Conventional threaded welding conductive nozzles maintain the thread shape while allowing easy replacement of the housing 20. However, the welding conductive nozzle of the present invention sets a larger torque wrench setting, causing plastic deformation of the thread teeth through excessive torque for thread-locking. Therefore, after integration, the adapter 10 and housing 20 are integrated, forming a structure that cannot be separated without special tools.

[0036] If the thread teeth are plastically deformed and the weld seam is fixed in this way, it is not possible to simply replace the enlarged housing 20 as in the past. However, this method has the following advantages: microscopically, the ventral surfaces of the external thread 14 and the internal thread 23 are formed in a surface contact state, stabilizing the current path from the adapter 10 to the housing 20 and suppressing welding current deviation. Furthermore, the welding contact tip of the present invention uses a molybdenum alloy with heat resistance and hardness for the end-side housing 20, thus extending its service life to more than 40 times that of existing products, reducing the necessity of replacing the housing 20. Consequently, the replacement frequency of the entire contact tip is significantly reduced when it reaches the end of its service life, resulting in a substantial decrease in overall cost and improved welding efficiency.

[0037] The advantages of the welding conductive tip of the present invention described above are summarized as follows.

[0038] (1) By reducing the diameter of the second central hole 23 on the end side and increasing the diameter of the first central hole 11 on the base side, it is possible to prevent the welding wire from being blocked and to allow the welding current to flow in a concentrated manner on the inner surface of the second central hole.

[0039] (2) The end-side housing 20 is made of a molybdenum alloy that has both heat resistance and hardness, so the service life is more than 40 times that of existing products.

[0040] (3) The length of the second central hole 23 of the hard molybdenum alloy shell 20 is shortened to less than 1 / 3 of the length of the first central hole, so that the perforation operation can be carried out accurately.

[0041] (4) The adapter 10 and housing 20 are manufactured separately, so various combinations can be achieved in accordance with the outer diameter of the welding wire and the full length of the conductive tip, thereby reducing manufacturing costs.

[0042] (5) By fixing the adapter 10 and the housing 20 with a seam, the power supply path from the adapter 10 to the housing 20 is stabilized, and the deviation of the welding current is suppressed. As a result, the welding quality can be greatly improved.

[0043] Explanation of reference numerals in the attached figures

[0044] 1. The main body of the existing conductive nozzle

[0045] 2. The center hole of the existing conductive nozzle

[0046] 3. End head

[0047] 10 adapters

[0048] 11 First central hole

[0049] 12 cylindrical main bodies

[0050] 13 Narrow-diameter cylindrical section

[0051] 14 External Thread

[0052] 15 External Thread

[0053] 16 conical expanded diameter sections

[0054] 20 housing

[0055] 21 Second center hole

[0056] 22 Cylindrical section

[0057] 23 Internal Thread

[0058] 24-hole section

[0059] 25 conical aperture

[0060] 26 main bodies

Claims

1. A welding conductive tip, wherein a molybdenum alloy housing having a second central hole with a diameter smaller than the first central hole is threadedly connected to the end of a copper alloy adapter having a first central hole, characterized in that, The end of the first central hole and the base of the second central hole are in contact via a tapered opening. The adapter and the housing are screwed together with a large torque, thereby causing plastic deformation of the thread teeth and achieving a closed-joint fixation. The length of the second central hole is less than 1 / 3 of the length of the first central hole, so that the welding current is concentrated on the inner surface of the second central hole and flows into the welding wire.

2. The conductive nozzle for welding according to claim 1, characterized in that, The housing is made of a molybdenum alloy containing titanium, zirconium, carbon, and the remainder being molybdenum, and the adapter is made of a copper alloy containing chromium.

3. The conductive nozzle for welding according to claim 1, characterized in that, The inner diameter of the second center hole is set to be 0.08 to 0.12 mm larger than the outer diameter of the welding wire used.

4. The conductive nozzle for welding according to claim 1, characterized in that, The total length of the adapter and the housing after they are combined is 40-45 mm, and the length of the second central hole is 5-15 mm.

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