JP2024065576A - Welding torch - Google Patents

Abstract

To provide a welding torch suitable for reduction in size and simplification in structure.SOLUTION: A welding torch A1 includes: an electrode 25 extending in an axial direction z; a first member 26 disposed outside the electrode 25; a nozzle 30 disposed outside the electrode 25; a locking member 33 fitted from outside across the first member 26 and the nozzle 30 to be locked on both of the first member 26 and the nozzle 30; and a centering member 34 disposed outside the electrode 25 and also inside the nozzle 30. The centering member 34 is fitted from outside to the electrode 25 in a concentric circular state, and the nozzle 30 is fitted from outside to the centering member 34 in a concentric circular state. The centering member 34 is inhibited from moving to the side z2 by contact between the end part on a z2 side and the end part on a z1 side of the first member 26, and inhibited from moving to the z1 side by contact between a centering member swollen part 342 and a nozzle primary part 301. The nozzle 30 is inhibited from moving to the z1 side by contact between a nozzle swollen part 302 and an intermediate step part 333.SELECTED DRAWING: Figure 8

Description

The present invention relates to a welding torch.

In welding (TIG welding and plasma welding) using a welding torch equipped with a non-consumable electrode, an arc is generated between the electrode (non-consumable electrode) made of tungsten and the workpiece, and the heat of the arc melts the workpiece. In TIG welding, shielding gas is flowed between the gas nozzle and the electrode. In plasma welding, in addition to the shielding gas, plasma gas is flowed inside the insert tip placed around the electrode, thereby constraining the arc (plasma arc). As a result, a highly concentrated high-temperature plasma flow is generated, and the stored energy is used to perform welding.

When welding metals with a relatively low melting point (low melting metals) such as zinc-plated steel sheets, zinc vapor and fumes are generated by the welding heat. If metals such as fumes adhere to the electrode, the arc generated during welding becomes unstable. In TIG welding, the tip of the electrode usually protrudes from the tip of the nozzle, and if the tip of the electrode is covered with metals such as fumes, there is a risk of poor ignition at the start of welding. In plasma welding, the tip of the electrode is usually retracted from the tip of the insert tip that surrounds the electrode. In addition, plasma gas is flowed inside the insert tip (around the electrode). For this reason, when welding low melting metals such as zinc-plated steel sheets, metals such as fumes are less likely to adhere to the electrode in plasma welding than in TIG welding. On the other hand, in plasma welding, metals such as fumes may adhere to the tip of the insert tip, which then alloys with the tip of the insert tip. This alloying of the tip of the insert tip may cause poor arcing or poor welding.

Patent Document 1 discloses a configuration in which multiple side plasma gas ejection holes made of small diameter holes are provided around the plasma gas ejection hole at the tip of the insert tip. By providing these multiple side plasma gas ejection holes, it is possible to reduce the adhesion of fumes and the like to the tip of the insert tip during welding. However, the structure described in Patent Document 1 makes the insert tip structure complex and leads to an increase in the size of the tip of the insert tip (welding torch). In addition, if the axis of the insert tip, which is arranged with a gap around the electrode, is offset from the axis of the electrode, there is a risk that the plasma gas ejected from the tip of the insert tip will drift, resulting in a decrease in welding quality.

JP 2009-172644 A

The present invention was conceived under these circumstances, and its main objective is to provide a welding torch that is suitable for simplifying the structure and making it smaller.

To solve the above problems, the present invention employs the following technical means:

The welding torch provided by the present invention comprises a non-consumable electrode extending in an axial direction, a cylindrical first member arranged radially outside the non-consumable electrode, a cylindrical first nozzle arranged radially outside the non-consumable electrode and on one side of the first member in the axial direction, a cylindrical locking member that is fitted across a first portion of the first member on one side of the axial direction and a second portion of the first nozzle on the other side of the axial direction and engages with both the first member and the first nozzle, and a cylindrical electrode centering member arranged radially outside the non-consumable electrode and radially inside the second portion, the electrode centering member being concentrically fitted around the non-consumable electrode, the electrode centering member including a cylindrical centering member main portion and a centering member bulging portion that bulges radially outward from the centering member main portion, the second portion being a cylindrical centering member main portion that is fitted over the centering member main portion. The second part is concentrically fitted around a portion located on one side of the material bulge in the axial direction, and the second part includes a cylindrical nozzle main part and a nozzle bulge that bulges outward in the radial direction from the other side of the nozzle main part in the axial direction. The locking member includes a large diameter tubular part that is fitted around the nozzle bulge, a small diameter tubular part that has an inner diameter smaller than that of the large diameter tubular part and is fitted around the nozzle main part, and an intermediate step part that is connected to both the large diameter tubular part and the small diameter tubular part. The electrode core member is prevented from moving to the other side in the axial direction by the end on the other side in the axial direction abutting against the first part, and the electrode core member is prevented from moving to one side in the axial direction by the abutment of the centering member bulge and the second part, and the first nozzle is prevented from moving to one side in the axial direction by the abutment of the nozzle bulge and the intermediate step part.

In a preferred embodiment, the centering member bulge portion has a first abutment surface located on one side in the axial direction, and the second portion has a second abutment surface that abuts against the first abutment surface, and each of the first abutment surface and the second abutment surface is inclined so that the radial dimension decreases toward one side in the axial direction.

In a preferred embodiment, the first portion has a third abutment surface located on one side in the axial direction, and the centering member bulge portion has a fourth abutment surface located on the other side in the axial direction and abutting against the third abutment surface, and each of the third abutment surface and the fourth abutment surface is inclined so that the radial dimension increases toward one side in the axial direction.

In a preferred embodiment, the nozzle bulge has a fifth abutment surface located on one side in the axial direction, and the intermediate step has a sixth abutment surface that abuts against the fifth abutment surface, and each of the fifth abutment surface and the sixth abutment surface is inclined so that the radial dimension decreases toward one side in the axial direction.

In a preferred embodiment, the large diameter cylindrical portion of the locking member and the first portion of the first member are connected by a screw thread.

In a preferred embodiment, the first nozzle is made of an insulating material.

In a preferred embodiment, the nozzle further includes a cylindrical second nozzle disposed radially outward of the first nozzle and the engaging member.

In the welding torch according to the present invention, the first nozzle is arranged concentrically with respect to the non-consumable electrode via the electrode centering member. The locking member is fitted across the first part on one side of the axial direction of the first member and the second part on the other side of the axial direction of the first nozzle, and is locked to both the first member and the first nozzle. With this configuration, some flexibility can be provided in the radial direction between the locking member and the first member or the first nozzle. Therefore, for example, even if the non-consumable electrode is slightly bent due to manufacturing errors, the first nozzle can be arranged concentrically with respect to the non-consumable electrode. If the first nozzle is misaligned, it is likely to cause a bias in the flow of gas flowing between the non-consumable electrode and the first nozzle, but as described above, the structure equipped with the electrode centering member and the locking member ensures that the first nozzle is arranged concentrically with respect to the non-consumable electrode. This is suitable for improving welding quality.

Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a front view showing an example of a welding torch according to the present invention. FIG. 2 is a plan view of the welding torch shown in FIG. 1 . 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 4 is an enlarged cross-sectional view taken along line VV in FIG. 3. FIG. 6 is an enlarged cross-sectional view taken along line VI-VI in FIG. FIG. 7 is an enlarged cross-sectional view taken along line VII-VII in FIG. FIG. 4 is a partially enlarged view of FIG. 3 . FIG. 4 is a partially enlarged view of FIG. 3 . FIG. 9 is a cross-sectional view similar to FIG. 8, showing a modified example of the welding torch according to the present invention. FIG. 10 is a cross-sectional view similar to FIG. 8, showing another modified example of the welding torch according to the present invention.

The preferred embodiment of the present invention will now be described in detail with reference to the drawings. In the following description, terms such as "first" and "second" are used merely as labels and are not necessarily intended to assign any order to the objects they refer to.

Figures 1 to 9 show an example of a welding torch according to the present invention. The welding torch A1 of this embodiment includes a handle 1, a torch body 2, insulating rings 23, 24, a non-consumable electrode 25, a collet body 26, a collet 27, a collet retainer 28, a cap 29, an inner nozzle 30, an outer nozzle 31, a nozzle holder 32, a locking member 33, an electrode centering member 34, a first gas pipe 41, a second gas pipe 42, a first cooling water pipe 43, and a second cooling water pipe 44. The welding torch A1 of this embodiment is configured so that an operator can hold it by hand to perform welding work. In addition, as will be described in detail later, the welding torch A1 has two gas flow paths (a first gas flow path G1 and a second gas flow path G2) for flowing a predetermined welding gas.

In the explanation of welding torch A1, the up-down direction in Figures 1 and 3 is an example of the "axial direction" of the present invention, and is referred to as the "axial direction z." In Figures 3 and 9, the direction perpendicular to the axial direction z (the left-right direction in the figures) is referred to as the "first direction x." Also, in Figures 1 and 3, the lower side in the figures is an example of the "one side of the axial direction" of the present invention, and is referred to as the "one side of the axial direction z1," and the upper side in the figures is an example of the "other side of the axial direction" of the present invention, and is referred to as the "other side of the axial direction z2."

The handle 1 is the part that the operator holds with his/her hand. As shown in FIG. 3, the handle 1 is a cylindrical member made of an insulating material.

The torch body 2 is cylindrical, and one end is held by the handle 1. The torch body 2 includes a main body 20, a cylindrical member 21, and a cylindrical member 22. The main body 20 appropriately houses the components of the welding torch A1 inside. The main body 20 is made of an insulating material. The main body 20 has a first cylindrical portion 20A and a second cylindrical portion 20B.

The first cylindrical portion 20A extends along the axial direction z. The second cylindrical portion 20B is connected to the first cylindrical portion 20A in a branched manner. The second cylindrical portion 20B extends in a direction intersecting the axial direction z (the upper right direction in FIG. 3). In the illustrated example, the angle between the direction in which the first cylindrical portion 20A extends (axial direction z) and the direction in which the second cylindrical portion 20B extends is about 65°. The angle between the direction in which the first cylindrical portion 20A extends (axial direction z) and the direction in which the second cylindrical portion 20B extends is not particularly limited, and may be, for example, a right angle (90°). The end of the second cylindrical portion 20B (the end on the upper right side in FIG. 3) is held by the end of the handle 1. In the illustrated example, the end of the second cylindrical portion 20B and the end of the handle 1 are fixed to each other by a screw connection.

The cylindrical member 21 is disposed radially inside the first cylindrical portion 20A. The cylindrical member 21 is a member that receives power from a power source unit (not shown) and is made of a conductive material. An example of the conductive material that constitutes the cylindrical member 21 is copper. As shown in FIG. 9, the cylindrical member 21 has a first gas inlet 211, a second gas inlet 212, a groove 213, a tapered surface 214, and a female threaded portion 215. The cylindrical member 22 is disposed radially outside the cylindrical member 21. Details of the cylindrical member 21 and the cylindrical member 22 will be described later.

The insulating rings 23 and 24 are each a cylindrical member made of an insulating material. The insulating ring 23 is disposed adjacent to the other axial side z2 of the first cylindrical portion 20A. The insulating ring 24 is disposed adjacent to one axial side z1 of the second cylindrical portion 20B.

The non-consumable electrode 25 is a rod-shaped conductor extending along the axial direction z (the direction in which the axis CL extends). The non-consumable electrode 25 is made of, for example, tungsten. The non-consumable electrode 25 is connected to a power supply (not shown) via, for example, a conduit cable (not shown), and generates an arc between the non-consumable electrode 25 and the workpieces when an arc voltage is applied between the non-consumable electrode 25 and the workpieces.

The non-consumable electrode 25 has an electrode main portion 251 and an electrode tapered portion 252. The electrode main portion 251 is a portion with a constant outer diameter, and occupies most of the non-consumable electrode 25 except for the tip. The electrode main portion 251 is a portion formed in an approximately cylindrical shape so that the outer diameter is constant in design, and may include some manufacturing errors. The outer diameter of the electrode main portion 251 is not particularly limited, and in this embodiment, it is, for example, about 1.6 to 4.0 mm. The electrode tapered portion 252 is connected to the tip side (one axial side z1) of the non-consumable electrode 25 relative to the electrode main portion 251. The electrode tapered portion 252 has a diameter that decreases toward the tip side (one axial side z1) of the non-consumable electrode 25, and is approximately conical.

The collet body 26, collet 27, and collet pressing member 28 cooperate with each other to hold the non-consumable electrode 25. The collet body 26, collet 27, and collet pressing member 28 are made of a conductive material. An example of the conductive material that constitutes the collet body 26, collet 27, and collet pressing member 28 is copper.

The collet 27 surrounds the non-consumable electrode 25. The collet body 26 is disposed radially outward of the collet 27. The collet body 26 is disposed radially inward of the cylindrical member 21. Although detailed illustrations are omitted, the collet body 26 is fixed to the cylindrical member 21, for example, by a screw connection.

The collet holding member 28 is disposed on the other axial side z2 relative to the collet 27. Although detailed illustrations are omitted, the collet holding member 28 has a screw portion that is screwed into the cylindrical member 21. As shown in FIG. 8, a female screw portion 215 is formed at the upper end (the end on the other axial side z2) of the cylindrical member 21, and the above-mentioned screw portion of the collet holding member 28 is screwed into the female screw portion 215. A cap 29 is provided on the other axial side z2 of the collet holding member 28. By turning this cap 29, the position of the collet holding member 28 in the axial direction z relative to the collet body 26 can be adjusted. The end of the collet holding member 28 on the one axial side z1 abuts against the end of the collet 27 on the other axial side z2. When the collet holding member 28 is moved to the one axial side z1, the collet 27 is pressed against the one axial side z1.

The collet 27 has multiple slits formed at its tip (one axial side z1) that extend in the axial direction z, and has multiple movable pieces 271 located between adjacent slits. As described above, when the collet pressing member 28 is moved toward one axial side z1, the collet 27 is pressed toward one axial side z1. Then, the multiple movable pieces 271 at the tip of the collet 27 are pressed against the tip of the collet body 26, reducing its diameter, and the collet 27 holds the non-consumable electrode 25 by sandwiching it. In this way, the collet body 26, collet 27, and collet pressing member 28 cooperate with each other to hold the non-consumable electrode 25.

As shown in FIG. 3, the inner nozzle 30 is disposed around the tip of the non-consumable electrode 25 (the end on one axial side z1). The inner nozzle 30 is disposed on one axial side z1 relative to the collet body 26. The inner nozzle 30 is roughly cylindrical and disposed radially outward of the non-consumable electrode 25 (electrode main portion 251). In this embodiment, an electrode centering member 34 is interposed between the inner nozzle 30 and the non-consumable electrode 25.

As shown in FIG. 8, the inner nozzle 30 includes a nozzle main portion 301, a nozzle bulge portion 302, and a tip side cylindrical portion 303. The nozzle main portion 301 is located toward the other axial side z2 and is approximately cylindrical. The nozzle bulge portion 302 bulges outward in the radial direction from the other axial side z2 of the nozzle main portion 301. The tip side cylindrical portion 303 is connected to the one axial side z1 of the nozzle main portion 301 and extends to the one axial side z1. The nozzle main portion 301 has a second abutment surface 301a. The second abutment surface 301a is a tapered surface that is inclined so that the radial dimension decreases as it approaches the one axial side z1. The nozzle bulge portion 302 has a fifth abutment surface 302a. The nozzle bulge portion 302 is a tapered surface that is inclined so that the radial dimension decreases as it approaches the one axial side z1. The inner nozzle 30 of the above configuration is made of an insulating material. The material of the inner nozzle 30 is not particularly limited, and examples of the material include ceramic materials such as alumina and resin materials such as heat-resistant phenol. The inner nozzle 30 corresponds to an example of the "first nozzle" of the present invention.

As shown in FIG. 8, the locking member 33 is fitted over both the collet body 26 and the inner nozzle 30. More specifically, the locking member 33 is fitted over the end (first part) of the collet body 26 on one axial side z1 and the end (second part) of the inner nozzle 30 on the other axial side z2.

The locking member 33 includes a large diameter cylindrical portion 331, a small diameter cylindrical portion 332, and an intermediate step portion 333. The large diameter cylindrical portion 331 is located on the other axial side z2 and is fitted onto the nozzle bulge portion 302. The small diameter cylindrical portion 332 has an inner diameter dimension smaller than that of the large diameter cylindrical portion 331. The small diameter cylindrical portion 332 is located on one axial side z1 and is fitted onto the nozzle main portion 301. The intermediate step portion 333 is provided at the center of the locking member 33 in the axial direction z and is connected to both the large diameter cylindrical portion 331 and the small diameter cylindrical portion 332. The large diameter cylindrical portion 331 has a female thread portion 331a. The female thread portion 331a is formed on the inner circumference of the large diameter cylindrical portion 331. The intermediate step portion 333 has a sixth abutment surface 333a. The sixth abutment surface 333a is formed on the inner circumference of the intermediate step portion 333. The sixth abutment surface 333a is a tapered surface that is inclined so that the radial dimension decreases toward one axial side z1. The sixth abutment surface 333a abuts against the fifth abutment surface 302a of the nozzle expansion portion 302. In the illustrated example, the locking member 33 has a cap nut structure.

In this embodiment, as shown in Figures 3 and 8, the locking member 33 (large diameter cylindrical portion 331) and the end (first portion) of the collet body 26 on one axial side z1 are screwed together. For example, a male thread 261a is formed on the outer periphery of the end of the collet body 26 on one axial side z1, and the female thread 331a formed on the locking member 33 (large diameter cylindrical portion 331) is screwed into the male thread 261a of the collet body 26. On the other hand, as shown in Figure 8, the small diameter cylindrical portion 332 on one axial side z1 of the locking member 33 is fitted onto the nozzle main portion 301, and the nozzle bulge portion 302 (fifth abutment surface 302a) on the other axial side z2 of the inner nozzle 30 is in abutment with the intermediate step portion 333 (sixth abutment surface 333a). This limits the relative movement of the inner nozzle 30 and the locking member 33 in the axial direction z, and prevents the inner nozzle 30 from moving to one axial side z1. The collet body 26 configured as described above corresponds to an example of the "first member" of the present invention.

As shown in FIG. 8, the electrode centering member 34 is cylindrical and is disposed radially outside the non-consumable electrode 25 and radially inside the inner nozzle 30. The electrode centering member 34 includes a centering member main portion 341 and a centering member bulge portion 342. The centering member main portion 341 is generally cylindrical. A recess 301b is formed on the inner circumference of the nozzle main portion 301 in the inner nozzle 30, and the centering member main portion 341 is fitted into this recess 301b. The centering member bulge portion 342 bulges outward in the radial direction from the centering member main portion 341. In the illustrated example, the centering member bulge portion 342 bulges outward in the radial direction from the other axial side z2 of the centering member main portion 341.

The centering member bulge 342 has a first abutment surface 342a and a fourth abutment surface 342b. The first abutment surface 342a and the fourth abutment surface 342b are formed on the outer periphery of the centering member bulge 342. The first abutment surface 342a is located on one axial side z1 and is a tapered surface that is inclined so that the radial dimension becomes smaller as it approaches the one axial side z1. The first abutment surface 342a abuts against the second abutment surface 301a of the nozzle main part 301. The fourth abutment surface 342b is located on the other axial side z2 and is a tapered surface that is inclined so that the radial dimension becomes larger as it approaches the one axial side z1. A third abutment surface 262a is formed at the end (first part) of the one axial side z1 of the collet body 26. The third abutment surface 262a is a tapered surface that is inclined so that the radial dimension increases toward one axial side z1, and is connected to the edge of one axial side z1 of the collet body 26. The fourth abutment surface 342b abuts against this third abutment surface 262a.

The inner diameter of the electrode centering member 34 (centering member main portion 341) is slightly larger than the outer diameter of the non-consumable electrode 25 (electrode main portion 251). As a result, the electrode centering member 34 is concentrically fitted around the non-consumable electrode 25. In addition, the inner diameter of the nozzle main portion 301 (recess 301b) of the inner nozzle 30 is slightly larger than the outer diameter of the centering member main portion 341. As a result, the inner nozzle 30 is concentrically fitted around the electrode centering member 34 (centering member main portion 341). Therefore, the inner nozzle 30 is arranged concentrically around the non-consumable electrode 25 via the electrode centering member 34.

In the illustrated mounting structure of the inner nozzle 30, the locking member 33, and the electrode centering member 34, the centering member bulge 342 (first abutment surface 342a) of the electrode centering member 34 abuts against the nozzle main portion 301 (second portion, second abutment surface 301a) of the inner nozzle 30. This limits the relative movement of the electrode centering member 34 and the inner nozzle 30 in the axial direction z, and the electrode centering member 34 is prevented from moving to one axial side z1. In addition, the centering member bulge 342 (fourth abutment surface 342b) of the electrode centering member 34 abuts against the end portion (first portion, third abutment surface 262a) of the collet body 26 on one axial side z1. This limits the relative movement of the electrode centering member 34 and the collet body 26 in the axial direction z, and the electrode centering member 34 is prevented from moving to the other axial side z2.

As shown in FIG. 7, a plurality of grooves 341a are formed on the inner periphery of the electrode core member 34 (centering member main portion 341). These grooves 341a are provided at regular intervals in the circumferential direction of the electrode core member 34. A gap is formed between the non-consumable electrode 25 and the portion where the grooves 341a are formed, and this gap constitutes the first gas flow path G1 described below.

As shown in FIG. 8, in this embodiment, the tip of the non-consumable electrode 25 coincides with the tip of the inner nozzle 30 in the axial direction z, or protrudes slightly from the tip of the inner nozzle 30 to one axial side z1. The protruding length P1 by which the tip of the non-consumable electrode 25 protrudes from the tip of the inner nozzle 30 to one axial side z1 is, for example, in the range of 0 to 2 mm.

The nozzle holder 32 is cylindrical. The nozzle holder 32 is integrally connected to the outer periphery of the middle part of the collet body 26 in the axial direction z by means of, for example, brazing.

3 and 8, the outer nozzle 31 is disposed radially outward of the inner nozzle 30. The outer nozzle 31 is disposed on one axial side z1 relative to the first cylindrical portion 20A, and an insulating ring 24 is interposed between the outer nozzle 31 and the first cylindrical portion 20A. In the illustrated example, the outer nozzle 31 is generally cylindrical, and the tip side (one axial side z1) has a smaller diameter than other portions. In this embodiment, the outer nozzle 31 is disposed concentrically with the non-consumable electrode 25 and the inner nozzle 30. The outer nozzle 31 is attached, for example, by a screw connection to the outer periphery of the nozzle holder 32. The outer nozzle 31 corresponds to an example of the "second nozzle" of the present invention.

As shown in FIG. 8, in this embodiment, the tip of the inner nozzle 30 protrudes from the tip of the outer nozzle 31 to one axial side z1. The protruding length P2 by which the tip of the inner nozzle 30 protrudes from the tip of the outer nozzle 31 to one axial side z1 is, for example, in the range of 0 to 5 mm.

As shown in Figures 3 to 9, in this embodiment, the welding torch A1 is formed with a first gas flow path G1, a second gas flow path G2, and a cooling water flow path W.

In this embodiment, the welding gas supplied to the welding torch A1 includes two types of inert gas that differ in gas supply manner, such as gas type and flow rate. For convenience of explanation, the two types of inert gas are appropriately distinguished as a "first inert gas" and a "second inert gas."

The first gas flow path G1 is a flow path for flowing the first inert gas. In Fig. 3 and Fig. 8, the flow of the first inert gas is indicated by the two-dot chain arrows. The first gas flow path G1 is formed between the collet 27 and the collet body 26, between the non-consumable electrode 25 (electrode main part 251) and the collet 27, between the non-consumable electrode 25 (electrode main part 251) and the collet body 26, between the non-consumable electrode 25 (electrode main part 251) and the electrode centering member 34 (centering member main part 341), and between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (tip side cylindrical part 303).

In this embodiment, as shown in Figures 3 and 9, the torch body 2 (cylindrical member 21) is provided with a first gas inlet 211 for introducing a first inert gas. The first gas inlet 211 is connected to the first gas flow passage G1. When the first inert gas is introduced from the first gas inlet 211, the first inert gas flows in the first gas flow passage G1 from the other axial side z2 to the one axial side z1, passes between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30, and then is ejected from the opening 305 at the tip of the inner nozzle 30.

The second gas flow path G2 is a flow path for flowing the second inert gas. In Figures 3 and 8, the flow of the second inert gas is indicated by dotted arrows. The second gas flow paths G2 are formed between the collet body 26 and the cylindrical member 21, between the collet body 26 and the insulating ring 24, between the nozzle holder 32, the locking member 33 and the outer nozzle 31, and between the inner nozzle 30 and the outer nozzle 31.

In this embodiment, as shown in Figures 3 and 9, the torch body 2 (cylindrical member 21) is provided with a second gas inlet 212 for introducing a second inert gas. The second gas inlet 212 is connected to the second gas flow passage G2. When the second inert gas is introduced from the second gas inlet 212, the second inert gas flows from the other axial side z2 to the one axial side z1 in the second gas flow passage G2, passes between the inner nozzle 30 and the outer nozzle 31, and is then ejected from the opening 315 at the tip of the outer nozzle 31.

The cooling water flow path W is a flow path for flowing cooling water. As shown in FIG. 4, the cooling water flow path W is formed along the circumferential direction of the non-consumable electrode 25. The cooling water flow path W is formed mainly between the cylindrical member 21 and the cylindrical member 22.

The first gas inlet 211, the second gas inlet 212, the groove 213, the tapered surface 214, and the female threaded portion 215 of the cylindrical member 21 will be described with reference to FIG. 9 and other figures. As shown in FIG. 9, the first gas inlet 211 is located on the other axial side z2 relative to the second gas inlet 212. The first gas inlet 211 is inclined with respect to the first direction x. The first gas inlet 211 is inclined to be located on one axial side z1 as it approaches the non-consumable electrode 25 in the first direction x.

The second gas inlet 212 is inclined with respect to the first direction x. The second gas inlet 212 is inclined so as to be located on one axial side z1 as it approaches the non-consumable electrode 25 in the first direction x. The first cylindrical portion 20A, which is located radially outside the cylindrical member 21, is positioned across the first gas inlet 211 and the second gas inlet 212 in the axial direction z.

The opening end of the second gas inlet 212 is located on the tapered surface 214. The tapered surface 214 is inclined so as to be located on the other axial side z2 as it approaches the non-consumable electrode 25. In the cross section shown in FIG. 9, the angle between the tapered surface 214 and the second gas inlet 212 is approximately a right angle.

The recessed groove 213 is a portion of the outer circumferential surface of the tubular member 21 recessed radially inward. The tubular member 22 is roughly cylindrical and is disposed radially outward of the tubular member 21. The tubular member 22 blocks the recessed groove 213 from the radially outward side. As shown in Figures 4 and 9, in this embodiment, the cooling water flow path W is formed by the space between the recessed groove 213 and the tubular member 22 that blocks it. Also, in this embodiment, as shown in Figure 9, the cooling water flow path W is located between the first gas inlet 211 and the tubular member 22 in the axial direction z.

As shown in FIG. 9, the female threaded portion 215 is adjacent to the first gas inlet 211 on the other axial side z2. As described above, the threaded portion of the collet retainer member 28 is screwed into this female threaded portion 215.

3 and 9, the first gas pipe 41 and the second gas pipe 42 pass through the inside of the second cylindrical portion 20B. The first gas pipe 41 is a pipe that flows through the first gas flow path G1 and is connected to the first gas inlet 211 of the cylindrical member 21. The second gas pipe 42 is a pipe that flows through the second gas flow path G2 and is connected to the second gas inlet 212 of the cylindrical member 21. The second cylindrical portion 20B has a narrowed shape in which the portion closer to the first cylindrical portion 20A has a smaller diameter than the portion closer to the handle 1. In the illustrated example, the first gas pipe 41 and the second gas pipe 42 are appropriately bent in accordance with the narrowed shape of the second cylindrical portion 20B. The end of the first gas pipe 41 that is connected to the first gas inlet 211 extends along the first direction x.

As shown in FIG. 4, the first cooling water pipe 43 and the second cooling water pipe 44 pass through the inside of the second cylindrical portion 20B. In the illustrated example, the first cooling water pipe 43 is a pipe for sending cooling water toward the above-mentioned cooling water flow path W. The second cooling water pipe 44 is a pipe for sending the cooling water that has flowed through the cooling water flow path W to the outside. The end of the first cooling water pipe 43 on the first cylindrical portion 20A side is connected to one end of the cooling water flow path W. The end of the second cooling water pipe 44 on the first cylindrical portion 20A is connected to the other end of the cooling water flow path W. As a result, as shown in FIG. 4, the cooling water flows in the order of the first cooling water pipe 43, the cooling water flow path W, and the second cooling water pipe 44. In FIG. 4, the flow of the cooling water is represented by solid arrows.

The type of each of the first inert gas and the second inert gas supplied to the welding torch A1 is not particularly limited, and may be, for example, a gas containing at least one selected from argon (Ar) gas and helium (He) gas. The flow rates of the first inert gas and the second inert gas supplied to the welding torch A1 are individually adjusted as appropriate depending on the welding conditions, etc.

As shown in FIG. 8, the gap between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (tip side cylindrical part 303) in the first gas flow path G1 is smaller than the gap between the inner nozzle 30 (tip side cylindrical part 303) and the outer nozzle 31 in the second gas flow path G2. The minimum gap L1 between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (tip side cylindrical part 303) in the first gas flow path G1 is, for example, about 0.4 to 1.8 mm. The minimum gap L2 between the inner nozzle 30 (tip side cylindrical part 303) and the outer nozzle 31 in the second gas flow path G2 is, for example, about 1 to 4 mm. Regarding the ratio of the minimum gap L1 to the minimum gap L2, the minimum gap L1 is, for example, 0.2 to 0.5 times the minimum gap L2, and preferably 0.2 to 0.3 times the minimum gap L2.

Next, the operation of this embodiment will be explained.

The welding torch A1 of this embodiment includes a non-consumable electrode 25 extending in the axial direction z, a collet body 26 (first member), an inner nozzle 30 (first nozzle), a locking member 33, and an electrode centering member 34. The electrode centering member 34 is concentrically fitted around the non-consumable electrode 25. The inner nozzle 30 (nozzle main part 301) is also concentrically fitted around the electrode centering member 34 (centering member main part 341). As a result, the inner nozzle 30 is arranged concentrically around the non-consumable electrode 25 via the electrode centering member 34. The locking member 33 is fitted across the end (first part) of the collet body 26 (first member) on one axial side z1 and the end (second part) of the inner nozzle 30 on the other axial side z2, and is locked to both the collet body 26 and the inner nozzle 30. This configuration allows some radial flexibility between the locking member 33 and the collet body 26 or the inner nozzle 30. Therefore, even if the non-consumable electrode 25 is slightly bent due to manufacturing errors, the inner nozzle 30 can be positioned concentrically with the non-consumable electrode 25.

If the inner nozzle 30 becomes misaligned with respect to the non-consumable electrode 25, the first inert gas (plasma gas) ejected from the opening 305 at the tip of the inner nozzle 30 will drift. The minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (tip side cylindrical portion 303) that constitute the first gas flow path G1 is narrow, and if the inner nozzle 30 becomes misaligned, it is likely to cause drift of the first inert gas (plasma gas). However, as described above, the structure that includes the electrode centering member 34 and the locking member 33 ensures that the inner nozzle 30 is positioned concentrically with the non-consumable electrode 25. This is suitable for improving welding quality.

In addition, since the inner nozzle 30 is arranged concentrically radially outside the non-consumable electrode 25, the gas (first inert gas) flowing through the first gas flow passage G1 between the non-consumable electrode 25 and the inner nozzle 30 becomes a substantially uniform and relatively high-speed airflow around the non-consumable electrode 25 and is ejected from the opening 305 at the tip of the inner nozzle 30. As a result, even when welding a workpiece made of a low-melting metal such as a galvanized steel sheet, fumes and the like generated during welding are blown away by the high-speed airflow of the first inert gas flowing around the non-consumable electrode 25. Therefore, it is possible to prevent fumes and the like from adhering to the tip of the non-consumable electrode 25 or the tip of the inner nozzle 30.

The locking member 33 and the end (first part) on one axial side z1 of the collet body 26 are screw-connected. This configuration allows for a suitable degree of dimensional flexibility between the locking member 33 and the collet body 26 with a relatively simple structure. In addition, when replacing the inner nozzle 30, the inner nozzle 30 can be easily removed by loosening the female threaded portion 331a of the locking member 33, making replacement of the inner nozzle 30 easy.

In the mounting structure of the inner nozzle 30, the locking member 33, and the electrode centering member 34, the end (centering member bulge 342) of the electrode centering member 34 on the other axial side z2 abuts against the end (first part) of the collet body 26 on one axial side z1. As a result, the electrode centering member 34 is prevented from moving toward the other axial side z2. In addition, the centering member bulge 342 of the electrode centering member 34 abuts against the nozzle main part 301 (second part) of the inner nozzle 30. As a result, the electrode centering member 34 is prevented from moving toward the one axial side z1. In addition, the nozzle bulge 302 on the other axial side z2 of the inner nozzle 30 abuts against the intermediate step part 333 of the locking member 33. As a result, the inner nozzle 30 is prevented from moving toward the one axial side z1. With this configuration, when the female threaded portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male threaded portion 261a of the collet body 26 are tightened, the portion on the other axial side z2 of the inner nozzle 30 (part of the nozzle main portion 301 and the nozzle bulge portion 302) is firmly held in place by compressive forces acting from both sides in the axial direction z by the centering member bulge portion 342 of the electrode centering member 34 and the intermediate step portion 333 of the locking member 33.

In this embodiment, the centering member bulge 342 of the electrode centering member 34 has a first abutment surface 342a located on one axial side z1. The nozzle main portion 301 of the inner nozzle 30 has a second abutment surface 301a that abuts against the first abutment surface 342a. Each of the first abutment surface 342a and the second abutment surface 301a is inclined so that the radial dimension decreases toward the one axial side z1. With this configuration, the centering accuracy of the inner nozzle 30 relative to the electrode centering member 34 can be improved.

In this embodiment, the end (first portion) of the collet body 26 on one axial side z1 has a third abutment surface 262a. The centering member bulge 342 of the electrode centering member 34 has a fourth abutment surface 342b located on the other axial side z2. The fourth abutment surface 342b abuts against the third abutment surface 262a, and each of the third abutment surface 262a and the fourth abutment surface 342b is inclined so that the radial dimension increases toward the one axial side z1. With this configuration, the centering accuracy of the electrode centering member 34 with respect to the non-consumable electrode 25 can be improved.

In this embodiment, the nozzle bulge 302 of the inner nozzle 30 has a fifth abutment surface 302a located on one axial side z1. The intermediate step 333 of the locking member 33 has a sixth abutment surface 333a that abuts against the fifth abutment surface 302a. Each of the fifth abutment surface 302a and the sixth abutment surface 333a is inclined so that the radial dimension decreases toward the one axial side z1. With this configuration, the centering accuracy of the inner nozzle 30 relative to the electrode centering member 34 can be further improved.

The inner nozzle 30 is made of an insulating material. The compressive strength of the insulating material is higher than the tensile strength. In this embodiment, as described above, the female threaded portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male threaded portion 261a of the collet body 26 are fastened together. As a result, the portion of the inner nozzle 30 on the other axial side z2 (a part of the nozzle main portion 301 and the nozzle bulge portion 302) is firmly held by the electrode core member 34 (core member bulge portion 342) and the locking member 33 (middle step portion 333) applying compressive forces from both sides in the axial direction z. This configuration is preferable for increasing the durability of the inner nozzle 30.

In this embodiment, the outer nozzle 31 is disposed radially outside the inner nozzle 30, and a second gas flow path G2 is formed between the inner nozzle 30 and the outer nozzle 31. With this configuration, during welding, the first inert gas flowing through the first gas flow path G1 and ejected from the tip of the inner nozzle 30 functions as a plasma gas, and the second inert gas flowing through the second gas flow path G2 and ejected from the tip of the outer nozzle 31 functions as a shielding gas. This narrows the arc generated between the workpiece and the tip of the non-consumable electrode 25, and welding can be performed efficiently using an arc with high energy density (plasma arc).

Furthermore, the tip of the non-consumable electrode 25 coincides with the tip of the inner nozzle 30 in the axial direction z, or protrudes slightly from the tip of the inner nozzle 30 to one axial side z1. The protruding length P1 of the tip of the non-consumable electrode 25 protruding from the tip of the inner nozzle 30 to one axial side z1 is in the range of 0 to 2 mm. With such a tip position of the non-consumable electrode 25, the gap between the non-consumable electrode 25 and the inner nozzle 30 is kept approximately constant and narrow in the range from the middle of the axial direction z of the inner nozzle 30 to the vicinity of the tip. Therefore, the high-speed airflow of the first inert gas flowing around the non-consumable electrode 25 is ejected from the opening 305 at the tip of the inner nozzle 30 with almost no decrease in flow rate. This is preferable in terms of preventing the adhesion of fumes, etc. to the tip of the non-consumable electrode 25 and the tip of the inner nozzle 30. In addition, the above-mentioned action and effect are realized by ingenuity in the shape and arrangement of the inner nozzle 30, making it possible to relatively simplify the structure of the welding torch A1 and to miniaturize the tip of the welding torch A1.

In the welding torch A1, the minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (tip side cylindrical portion 303) in the first gas flow passage G1 is smaller than the minimum gap L2 between the inner nozzle 30 (tip side cylindrical portion 303) and the outer nozzle 31 in the second gas flow passage G2. With this configuration, it is possible to efficiently increase the flow rate of the first inert gas flowing between the non-consumable electrode 25 and the inner nozzle 30. Therefore, adhesion of fumes and the like to the tip of the non-consumable electrode 25 and the tip of the inner nozzle 30 is appropriately prevented, and the arc (plasma arc) generated between the workpiece and the non-consumable electrode 25 is constricted, and the concentration of the arc is further increased.

Figure 10 shows a modified example of the welding torch according to the present invention. In the welding torch A11 shown in Figure 10, the configurations of the collet body 26, the inner nozzle 30, the locking member 33, and the electrode centering member 34 are different from those of the welding torch A1 of the above embodiment.

In the welding torch A11, the third abutment surface 262a of the above embodiment is not formed at the end of the collet body 26 on one axial side z1. The centering member bulge 342 of the electrode centering member 34 is not formed with the fourth abutment surface 342b. The annular flat end surface facing the other axial side z2 of the electrode centering member 34 (centering member main portion 341 and centering member bulge 342) abuts against the annular flat end surface facing the one axial side z1 of the collet body 26. The nozzle bulge 302 of the inner nozzle 30 is not formed with the fifth abutment surface 302a of the above embodiment. The intermediate step portion 333 of the locking member 33 is not formed with the sixth abutment surface 333a. The annular flat end surface of the nozzle bulge 302 facing one axial side z1 abuts against the annular flat end surface of the intermediate step 333 facing the other axial side z2.

In the welding torch A11 of this modified example, as in the welding torch A1 of the above embodiment, the inner nozzle 30 is arranged concentrically with the non-consumable electrode 25 via the electrode centering member 34. The locking member 33 is fitted across the end (first part) of the collet body 26 (first member) on one axial side z1 and the end (second part) of the inner nozzle 30 on the other axial side z2, and locks onto both the collet body 26 and the inner nozzle 30. With this configuration, some flexibility can be provided in the radial direction between the locking member 33 and the collet body 26 or the inner nozzle 30. Therefore, for example, even if the non-consumable electrode 25 is slightly bent due to manufacturing errors, the inner nozzle 30 can be arranged concentrically with the non-consumable electrode 25.

If the inner nozzle 30 becomes misaligned with respect to the non-consumable electrode 25, the first inert gas (plasma gas) ejected from the opening 305 at the tip of the inner nozzle 30 will drift. The minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (tip side cylindrical portion 303) that constitute the first gas flow path G1 is narrow, and if the inner nozzle 30 becomes misaligned, it is likely to cause drift of the first inert gas (plasma gas). However, as described above, the structure that includes the electrode centering member 34 and the locking member 33 ensures that the inner nozzle 30 is positioned concentrically with the non-consumable electrode 25. This is suitable for improving welding quality.

In the welding torch A11, the end of the electrode centering member 34 on the other axial side z2 (centering member main part 341 and centering member bulge part 342) abuts against the end of the collet body 26 on one axial side z1 (first part). As a result, the electrode centering member 34 is prevented from moving toward the other axial side z2. In addition, the centering member bulge part 342 of the electrode centering member 34 abuts against the nozzle main part 301 (second part) of the inner nozzle 30. As a result, the electrode centering member 34 is prevented from moving toward the one axial side z1. In addition, the nozzle bulge part 302 on the other axial side z2 of the inner nozzle 30 abuts against the intermediate step part 333 of the locking member 33. As a result, the inner nozzle 30 is prevented from moving toward the one axial side z1. With this configuration, when the female threaded portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male threaded portion 261a of the collet body 26 are tightened, the portion on the other axial side z2 of the inner nozzle 30 (part of the nozzle main portion 301 and the nozzle bulge portion 302) is firmly held in place by compressive forces acting from both sides in the axial direction z by the centering member bulge portion 342 of the electrode centering member 34 and the intermediate step portion 333 of the locking member 33.

In the welding torch A11, the centering member bulge 342 of the electrode centering member 34 has a first abutment surface 342a located on one axial side z1. The nozzle main portion 301 of the inner nozzle 30 has a second abutment surface 301a that abuts against the first abutment surface 342a. Each of the first abutment surface 342a and the second abutment surface 301a is inclined so that the radial dimension decreases toward the one axial side z1. With this configuration, the centering accuracy of the inner nozzle 30 relative to the electrode centering member 34 can be improved. In addition, the welding torch A11 has the same effects as the welding torch A1 of the above embodiment within the same range of configuration as the welding torch A1 of the above embodiment.

Figure 11 shows another modified example of the welding torch according to the present invention. In the welding torch A12 shown in Figure 11, the configuration of the inner nozzle 30 and the electrode centering member 34 is different from that of the modified welding torch A11 shown in Figure 10.

In the welding torch A12, the centering member bulge 342 of the electrode centering member 34 does not have a first abutment surface 342a. In addition, the nozzle main part 301 of the inner nozzle 30 does not have a second abutment surface 301a. The annular flat end surface facing one axial side z1 of the centering member bulge 342 abuts against the annular flat end surface facing the other axial side z2 of the nozzle main part 301.

In the welding torch A12 of this modified example, as in the welding torch A1 of the above embodiment, the inner nozzle 30 is arranged concentrically with the non-consumable electrode 25 via the electrode centering member 34. The locking member 33 is fitted across the end (first part) of the collet body 26 (first member) on one axial side z1 and the end (second part) of the inner nozzle 30 on the other axial side z2, and locks onto both the collet body 26 and the inner nozzle 30. With this configuration, some flexibility can be provided in the radial direction between the locking member 33 and the collet body 26 or the inner nozzle 30. Therefore, for example, even if the non-consumable electrode 25 is slightly bent due to manufacturing errors, the inner nozzle 30 can be arranged concentrically with the non-consumable electrode 25.

If the inner nozzle 30 becomes misaligned with respect to the non-consumable electrode 25, the first inert gas (plasma gas) ejected from the opening 305 at the tip of the inner nozzle 30 will drift. The minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (tip side cylindrical portion 303) that constitute the first gas flow path G1 is narrow, and if the inner nozzle 30 becomes misaligned, it is likely to cause drift of the first inert gas (plasma gas). However, as described above, the structure that includes the electrode centering member 34 and the locking member 33 ensures that the inner nozzle 30 is positioned concentrically with the non-consumable electrode 25. This is suitable for improving welding quality.

In the welding torch A12, the end of the electrode centering member 34 on the other axial side z2 (centering member main part 341 and centering member bulge part 342) abuts against the end of the collet body 26 on one axial side z1 (first part). As a result, the electrode centering member 34 is prevented from moving toward the other axial side z2. In addition, the centering member bulge part 342 of the electrode centering member 34 abuts against the nozzle main part 301 (second part) of the inner nozzle 30. As a result, the electrode centering member 34 is prevented from moving toward the one axial side z1. In addition, the nozzle bulge part 302 on the other axial side z2 of the inner nozzle 30 abuts against the intermediate step part 333 of the locking member 33. As a result, the inner nozzle 30 is prevented from moving toward the one axial side z1. With this configuration, when the female threaded portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male threaded portion 261a of the collet body 26 are fastened, the portion of the inner nozzle 30 on the other axial side z2 (a part of the nozzle main portion 301 and the nozzle bulge portion 302) is firmly held in place by compressive forces acting from both sides in the axial direction z by the centering member bulge portion 342 of the electrode centering member 34 and the intermediate step portion 333 of the locking member 33. In addition, the welding torch A12 has the same effects as the welding torch A1 of the above embodiment within the same range of configuration as the welding torch A1 of the above embodiment.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-mentioned embodiments, and all modifications within the scope of the matters described in each claim are included in the scope of the present invention.

In the above embodiment, the female threaded portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male threaded portion 261a of the collet body 26 are screwed together to lock the locking member 33 to the end of the collet body 26 on one axial side z1, but this configuration is not limited to this. For example, the locking member 33 may be configured to lock to the end of the collet body 26 on one axial side z1 by fitting the end of the collet body 26 on one axial side z1 with the locking member 33 (large diameter cylindrical portion 331) in a press-fit state.

A1, A11, A12: welding torch, 25: non-consumable electrode, 26: collet body (first member), 30: inner nozzle (first nozzle), 301: nozzle main part, 301a: second abutment surface, 302: nozzle bulge, 31: outer nozzle (second nozzle), 33: locking member, 331: large diameter cylindrical part, 332: small diameter cylindrical part, 333: intermediate step, 34: electrode core member, 341: core member main part, 342: core member bulge, 342a: first abutment surface, z: axial direction, z1: one side of axial direction, z2: other side of axial direction

Claims (5)

a non-consumable electrode extending in an axial direction;
a cylindrical first member disposed radially outward of the non-consumable electrode;
a cylindrical first nozzle disposed radially outward of the non-consumable electrode and on one side of the first member in the axial direction;
a cylindrical locking member that is fitted across a first portion of the first member on one side in the axial direction and a second portion of the first nozzle on the other side in the axial direction and that is locked to both the first member and the first nozzle;
a cylindrical electrode centering member disposed radially outside the non-consumable electrode and radially inside the second portion,
the electrode centering member is concentrically fitted around the non-consumable electrode,
the electrode centering member includes a cylindrical centering member main portion and a centering member bulging portion that bulges radially outward from the centering member main portion,
the second portion is concentrically fitted onto a portion of the main portion of the centering member that is located on one side of the centering member bulging portion in the axial direction,
the second portion includes a cylindrical nozzle main portion and a nozzle bulge portion that bulges radially outward from the other side of the nozzle main portion in the axial direction,
the engaging member includes a large diameter cylindrical portion fitted onto the nozzle bulge portion, a small diameter cylindrical portion having an inner diameter dimension smaller than that of the large diameter cylindrical portion and fitted onto the nozzle main portion, and an intermediate step portion connected to both the large diameter cylindrical portion and the small diameter cylindrical portion,
the electrode core-aligning member is prevented from moving toward the other side in the axial direction by an end portion on the other side in the axial direction abutting against the first portion,
the electrode centering member is prevented from moving to one side in the axial direction by the centering member bulging portion and the second portion coming into contact with each other,
A welding torch, wherein the first nozzle is prevented from moving to one side in the axial direction by the nozzle bulge portion and the intermediate step portion abutting against each other. the centering member bulge portion has a first abutment surface located on one side in the axial direction,
The second portion has a second abutment surface that abuts against the first abutment surface,
The welding torch according to claim 1 , wherein each of the first contact surface and the second contact surface is inclined so that a radial dimension thereof decreases toward one side in the axial direction. The welding torch according to claim 1 or 2, wherein the large diameter cylindrical portion of the locking member and the first portion of the first member are connected by a screw connection. The welding torch of claim 3, wherein the first nozzle is made of an insulating material. The welding torch of claim 4, further comprising a cylindrical second nozzle disposed radially outward of the first nozzle and the engaging member.

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