JP7557312B2 - Welding torch - Google Patents

Description

The present invention relates to a welding torch.

For example, a welding torch used in consumable electrode arc welding is configured so that a welding wire is fed while receiving power from a power feed tip. The welding wire is passed through a wire insertion hole in the power feed tip and receives power by contacting the inner surface of the wire insertion hole. A welding torch is described, for example, in Patent Document 1.

As shown in Patent Document 1, the welding torch includes a torch body, a tip body, a power feed tip, and a nozzle. All of these are cylindrical, and the tip body is attached to the tip of the torch body. The power feed tip is attached to the tip of the tip body. The nozzle is a cylindrical member that forms an annular space that is open forward outside the tip body or power feed tip.

The welding wire passing through the inside of the welding torch is guided by a guide member such as a coil liner as it is fed out. The coil liner is made by winding a metal wire in a spiral shape. The coil liner is inserted, for example, from the base end side of the torch body and is placed in the internal space of the torch body or tip body. This coil liner extends close to the power supply tip, and the welding wire is inserted inside the coil liner.

The welding torch is also configured to eject shielding gas, such as an inert gas, from a nozzle at the tip. When shielding gas is sent to the welding torch, it passes through the internal space of the torch body and tip body, and is sent to the inner space of the nozzle, for example, via an orifice member attached to the tip of the tip body, and is ejected from the tip of the nozzle. The internal space of the torch body and tip body serves as a flow path through which the shielding gas flows. In addition, when a coil liner is placed in the internal space of the torch body and tip body, an appropriate gap is provided between the coil liner and the inner surface of the torch body or tip body, and the shielding gas mainly flows through this gap.

However, the coil liner is inserted into the internal space of the torch body and tip body, and may be positioned unevenly, such as along the inner surface of the torch body or tip body. This causes an uneven flow path of the shielding gas in the internal space of the torch body or tip body. When an uneven flow path of the shielding gas in the internal space occurs, the gas flow ejected from the nozzle tip becomes uneven. This reduces the gas shielding performance during welding, adversely affecting the welding quality. In addition, the torch body may have a curved portion to make it easier for the worker to work, and in this case, the coil liner tends to follow the inner surface of the part that bulges outward in the curved portion, which makes it easy for the shielding gas flow path to become uneven.

JP 2010-214412 A

The present invention was conceived under these circumstances, and its main objective is to provide a welding torch suitable for reducing bias in the shielding gas flow path in the internal space of the torch body and tip body, in which a coil liner is disposed and shielding gas flows through the internal space, and for improving gas shielding during welding.

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

The welding torch provided by the present invention comprises a cylindrical torch body, a cylindrical tip body attached to the tip of the torch body, and a coil liner for passing a welding wire, which is formed by spirally winding metal wire and is disposed in the internal space of the torch body and the tip body, the internal space being a flow path through which a shielding gas flows, and at least one of the coil liner, the torch body, and the tip body has a protruding portion that protrudes so that the torch body or the tip body is closer to or abuts the coil liner than other portions.

In a preferred embodiment, the protrusion includes an outer protrusion having an outer diameter larger than other portions of the coil liner.

In a preferred embodiment, the protrusion includes an inner protrusion that protrudes radially inward from the inner peripheral surface of the torch body or tip body.

In a preferred embodiment, the inner protrusion is a portion that is pressed into the torch body or tip body so as to occupy a portion of the internal space.

In a preferred embodiment, the protrusions are provided at multiple locations spaced apart from one another in the axial direction of the coil liner.

The welding torch according to the present invention has a protruding portion, which prevents the coil liner from being positioned unevenly relative to the inner surface of the torch body or tip body, and a gap is formed between the coil liner and the inner surface almost evenly in the circumferential direction of the inner surface. This reduces the unevenness of the shielding gas flow path in the internal space of the torch body or tip body, improving gas shielding during welding. As a result, improved welding quality can be expected.

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

1 shows a first embodiment of a welding torch according to the present invention, partially shown in a vertical cross-sectional view. FIG. 2 is a longitudinal sectional view of a main portion of the welding torch shown in FIG. 1 . FIG. 3 is a partially enlarged view of FIG. 2 . FIG. 3 is a longitudinal sectional view of a main portion showing a first modified example of the welding torch of the first embodiment shown in FIG. 2. FIG. 3 is a longitudinal sectional view of a main portion showing a second modified example of the welding torch of the first embodiment shown in FIG. 2. FIG. 4 is a longitudinal sectional view showing a main portion of a second embodiment of a welding torch according to the present invention. FIG. 11 is a longitudinal sectional view showing a main portion of a third embodiment of a welding torch according to the present invention. 8 is a partially enlarged cross-sectional view taken along line VIII-VIII in FIG. 7. FIG. 11 is a longitudinal sectional view showing a main portion of a fourth embodiment of a welding torch according to the present invention. FIG. 13 is a longitudinal sectional view showing a main portion of a fifth embodiment of a welding torch according to the present invention. FIG. 11 is a partially enlarged view of FIG.

A preferred embodiment of the present invention will now be described in detail with reference to the drawings.

Figures 1 and 2 show a first embodiment of a welding torch according to the present invention. The welding torch A1 of this embodiment includes a handle 1, a torch body 2, a tip body 3, an insulator 4, an orifice member 5, a nozzle 6, a power supply tip 7, and a coil liner 8.

The handle 1 is the part that the worker holds in his/her hand. The torch switch 11 is the operating part that the worker uses to start and stop welding. The handle 1 is not an essential part of the present invention, so most of the description is omitted.

The torch body 2 is cylindrical, and its base end is held by the handle 1. In the example shown in FIG. 1, the torch body 2 has a curved portion to make it easier for the operator to perform welding work. As shown in FIG. 2, the tip of the torch body 2 has a cylindrical inner surface 21.

The tip body 3 is cylindrical and is attached to the tip of the torch body 2. The tip body 3 has a cylindrical inner circumferential surface 31. The tip body 3 is attached to the tip of the torch body 2 by a screw means 32. The tip body 3 is also formed of a conductive metal and receives a welding current from the torch body 2. In the example shown in FIG. 2, the inner diameter of the inner circumferential surface 31 of the tip body 3 is approximately the same as the inner diameter of the inner circumferential surface 21 of the torch body 2. The inner diameter of the inner circumferential surface 31 and the inner diameter of the inner circumferential surface 21 may be different. A tapered portion 34 is formed near the tip of the tip body 3. The tapered portion 34 is tapered so that the diameter decreases toward the tip of the tip body 3.

The insulator 4 is cylindrical and fitted onto the outer surface of the axially middle portion of the chip body 3. In this embodiment, the insulator 4 includes an insulating bush 41 and a base 42. The insulating bush 41 is formed of an insulating material such as a heat-resistant hard resin, and is connected to the chip body 3 by a screw means 411.

The base 42 is fitted and fixed to the insulating bush 41 from the base end to the tip end of the insulating bush 41. The base 42 is made of a metal such as brass. A male thread portion 421 is formed on the outer periphery of the tip end side of the base 42. The male thread portion 421 is configured as a trapezoidal screw, for example.

The orifice member 5 is fitted onto the outer surface of the axial tip of the tip body 3. The orifice member 5 is arranged adjacent to the insulator 4 in the axial direction of the tip body 3. This orifice member 5 will be described in more detail later.

The power supply tip 7 is attached to the tip of the tip body 3. The base end of the power supply tip 7 is attached to the tip body 3 by a screw means 71. A wire insertion hole 72 for passing a welding wire is formed through the power supply tip 7 from the base end to the tip. At the base end of the power supply tip 7, the wire insertion hole 72 is tapered, and the welding wire (not shown) fed to the welding torch A1 is fed to the tip side of the power supply tip 7 while being centered and guided by the tapered portion.

The nozzle 6 is a cylindrical member that forms an annular space that is open forward outside the tip body 3 or the power supply tip 7. A female thread 61 is formed on the inner periphery of the base end side of the nozzle 6. The female thread 61 can be screwed into the male thread 421 of the insulator 4 (base 42), and the nozzle 6 is attached to the insulator 4 (base 42) by screwing into the male thread 321.

The coil liner 8 is disposed in the internal space S of the torch body 2 and the tip body 3. The coil liner 8 is formed by winding a metal wire in a spiral shape. The coil liner 8 is inserted from the base end side of the torch body 2 and disposed in the internal space S of the torch body 2 and the tip body 3. A predetermined gap is provided between the coil liner 8 and the inner peripheral surface 21 of the torch body 2, and between the coil liner 8 and the inner peripheral surface 31 of the tip body 3. The coil liner 8 extends close to the power supply tip 7, and in the illustrated example, the tip of the coil liner 8 is close to or in contact with the tapered portion 34 of the tip body 3. The welding wire (not shown) fed to the welding torch A1 is guided through the inside of the coil liner 8 in the internal space S of the torch body 2 and the tip body 3, passes through the wire insertion hole 72 of the power supply tip 7, and is led out from the tip of the power supply tip 7.

In this embodiment, the coil liner 8 has a large diameter portion 81. The large diameter portion 81 is a portion of the coil liner 8 whose outer diameter is larger than the other portions. In the example shown in FIG. 2, the large diameter portion 81 is located inside the chip body 3 and protrudes so as to be close to or in contact with the inner peripheral surface 31 of the chip body 3. The large diameter portion 81 configured in this manner corresponds to an example of an outer protruding portion (protruding portion) of the present invention. Also, as described above, the tip of the coil liner 8 abuts against the tapered portion 34 of the chip body 3. The tapered portion 34 is a portion of the chip body 3 that protrudes radially inward beyond its inner peripheral surface 31. This tapered portion 34 corresponds to an example of an inner protruding portion (protruding portion) of the present invention.

As an example of the dimensions of the torch body 2, the tip body 3, and the coil liner 8, as shown in FIG. 3, the inner diameter dimension D1 of the inner peripheral surface 21 of the torch body 2 and the inner peripheral surface 31 of the tip body 3 is about 7 mm, and the outer diameter dimension D2 of the coil liner 8 is about 6 mm. The gap L1 between the outer peripheral portion of the coil liner 8 and the inner peripheral surfaces 21, 31 of the torch body 2 and the tip body 3 is about 0.5 mm. The outer diameter dimension Dmax of the large diameter portion 81 of the coil liner 8 is about 6.8 to 7 mm. The gap L2 between the large diameter portion 81 (outer peripheral portion) and the inner peripheral surface 31 of the tip body 3 is about 0 to 0.1 mm, which is very small. The diameter d3 (wire diameter) of the metal wire wound in a spiral shape in the coil liner 8 is, for example, about 1.6 mm, and the gap L3 between adjacent metal wires is, for example, about 0 to 0.5 mm. However, the above dimensions are just examples, and the dimensions of each part are not limited to the dimensions given above.

The welding torch A1 is also configured to eject shielding gas, such as an inert gas, from the nozzle 6 at the tip. Specifically, an annular hole 51 is formed on the inner circumference of the orifice member 5 to form an annular space 52 between the outer surface of the tip body 3, and the annular space 52 is connected to the space inside the nozzle 6 through an orifice hole 53. The tip body 3 is also formed with a vent hole 33 that connects its internal space S to the annular space 52. When shielding gas is sent to the welding torch A1, the shielding gas passes through the internal space S of the torch body 2 and the tip body 3, and is sent from the vent hole 33, the annular space 52 of the orifice member 5, or the orifice hole 53 to the inner space of the nozzle 6, and is finally ejected from the tip of the nozzle 6.

The internal space S of the torch body 2 and the tip body 3 serves as a flow path through which the shielding gas flows. In addition, since the coil liner 8 is disposed in the internal space S of the torch body 2 and the tip body 3, the shielding gas mainly flows through the gap provided between the coil liner 8 and the inner circumferential surfaces 21, 31 of the torch body 2 and the tip body 3.

Next, the operation of this embodiment will be explained.

In this embodiment, the coil liner 8 is disposed in the internal space S of the torch body 2 and the tip body 3. The internal space S serves as a gas flow path through which the shielding gas flows, and as described above, the shielding gas mainly flows through the gap provided between the coil liner 8 and the inner circumferential surfaces 21, 31 of the torch body 2 and the tip body 3. The coil liner 8 has a large diameter portion 81, which has an outer diameter larger than other parts of the coil liner 8 and protrudes so as to be close to or in contact with the tip body 3. With this configuration, the arrangement of the coil liner 8 is prevented from being biased relative to the inner circumferential surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner circumferential surface 31 almost evenly in the circumferential direction of the inner circumferential surface 31. This reduces the bias of the shielding gas flow path in the internal space S, improving the gas shielding during welding. As a result, improvement in welding quality can be expected.

The tip body 3 has a tapered portion 34. The tapered portion 34 is a portion of the tip body 3 that protrudes radially inward from its inner peripheral surface 31, and the tip of the coil liner 8 is close to or in contact with the tapered portion 34. With this configuration, the bias of the shielding gas flow path in the internal space S near the tip of the tip body 3 is appropriately reduced.

In this embodiment, the large diameter portion 81 and the tapered portion 34 are provided at multiple locations (two locations in this embodiment) that are spaced apart from each other in the axial direction of the coil liner 8 (the vertical direction in FIG. 2). This allows the coil liner 8 to properly center with respect to the inner circumferential surface 31. This is preferable for reducing bias in the shielding gas flow path in the internal space S and improving gas shielding during welding.

In the example shown in FIG. 3, the large diameter portion 81 of the coil liner 8 has a small gap between the large diameter portion 81 (outer periphery) and the inner periphery 31 of the tip body 3, and the large diameter portion 81 is close to the inner periphery 31. In the present invention, "close" means that when the axis of the coil liner 8 and the axis of the tip body 3 (inner periphery 31) coincide with each other, there is a uniform gap in the circumferential direction between the large diameter portion 81 (outer periphery) and the inner periphery 31. When the welding torch A1 is used, if the axis of the coil liner 8 deviates slightly from the axis of the tip body 3 (inner periphery 31), a part of the large diameter portion 81 (outer periphery) comes into contact with the inner periphery 31, and the centering effect of the coil liner 8 is obtained.

Unlike the example shown in FIG. 3, the large diameter portion 81 may abut against the inner peripheral surface 31. In the present invention, "abutment" means a state in which the large diameter portion 81 (outer peripheral portion) and the inner peripheral surface 31 are in contact with no gap when the axis of the coil liner 8 and the axis of the tip body 3 (inner peripheral surface 31) coincide with each other. When the large diameter portion 81 abuts against the inner peripheral surface 31, for example, the outer diameter dimension of the large diameter portion 81 in the natural state is set slightly larger than the inner diameter dimension of the inner peripheral surface 31, and when the coil liner 8 is inserted into the internal space S of the torch body 2 and the tip body 3, the large diameter portion 81 (outer peripheral portion) slides against the inner peripheral surfaces 21, 31.

The number of turns of the large diameter portion 81 of the coil liner 8 is not particularly limited, but is, for example, about 1 to 3 turns. If the number of turns of the large diameter portion 81 is increased, the flow resistance of the shielding gas flow path in the internal space S increases. Also, when the large diameter portion 81 abuts against the inner circumferential surface 31, if the number of turns of the large diameter portion 81 is increased, the sliding resistance of the large diameter portion 81 increases when the coil liner 8 is set, which is not preferable.

In this embodiment, the tip of the tip body 3 has a tapered portion 34, but the tip body 3 may not have such a tapered portion 34. The tip body 3 may not have a tapered portion 34, and this is also true for the modified examples and other embodiments described below.

Figure 4 shows a first modified example of a welding torch in the first embodiment. In the figures following Figure 4, elements that are the same as or similar to those in the first embodiment are given the same reference numerals as in the first embodiment, and descriptions thereof will be omitted as appropriate.

In the welding torch A11 shown in FIG. 4, the arrangement of the large diameter portion 81 in the coil liner 8 differs from that of the above embodiment. In the welding torch A11, two large diameter portions 81 are provided inside the tip body 3.

Even in this modified welding torch A11, the coil liner 8 is prevented from being positioned offset relative to the inner circumferential surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner circumferential surface 31 almost evenly in the circumferential direction of the inner circumferential surface 31. This reduces offsetting of the shielding gas flow path in the internal space S, improving gas shielding during welding. As a result, improved welding quality can be expected.

In this modified example, the large diameter portion 81 and the tapered portion 34 are provided at multiple locations (three locations in this embodiment) that are spaced apart from each other in the axial direction of the coil liner 8 (the vertical direction in FIG. 4). This allows the coil liner 8 to properly center against the inner circumferential surface 31. This is preferable for reducing bias in the shielding gas flow path in the internal space S and improving gas shielding during welding.

Figure 5 shows a second modified example of the welding torch of the first embodiment. In the welding torch A12 shown in Figure 5, the arrangement of the large diameter portion 81 in the coil liner 8 differs from that of the above embodiment. In the welding torch A12, one large diameter portion 81 is provided inside the torch body 2 and one inside the tip body 3.

In the welding torch A12 of this modified example, the arrangement of the coil liner 8 is prevented from being biased relative to the inner circumferential surface 21 of the torch body 2 and the inner circumferential surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner circumferential surfaces 21, 31 almost evenly in the circumferential direction of the inner circumferential surfaces 21, 31. This reduces bias in the shielding gas flow path in the internal space S, improving gas shielding during welding. As a result, improved welding quality can be expected.

In this modified example, the large diameter portion 81 and the tapered portion 34 are provided at multiple locations (three locations in this embodiment) that are spaced apart from each other on the coil liner 8 (in the vertical direction in FIG. 5). This allows the coil liner 8 to properly center with respect to the inner circumferential surfaces 21, 31. This is preferable in terms of reducing bias in the shielding gas flow path in the internal space S and improving gas shielding during welding.

In the welding torch A12, the large diameter portion 81 is provided to correspond to the inner peripheral surface 21 of the straight portion near the tip of the torch body 2, but the large diameter portion 81 may be provided to correspond to the inner peripheral surface 21 of the curved portion of the torch body 2.

Figure 6 shows a second embodiment of the welding torch according to the present invention. In the welding torch A2 shown in Figure 6, the configuration of the coil liner 8 and the tip body 3 differs from that of the first embodiment.

In this embodiment, the coil liner 8 does not have a large diameter portion 81, and has a substantially uniform outer diameter dimension over its entire length. The tip body 3 has a reduced diameter portion 35. The reduced diameter portion 35 is a portion of the tip body 3 that protrudes radially inward beyond its inner circumferential surface 31. In the example shown in FIG. 6, the reduced diameter portion 35 is annular and is adjacent to or in contact with the outer periphery of the coil liner 8. The reduced diameter portion 35 having such a configuration corresponds to an example of an inward protruding portion (protruding portion) of the present invention.

When the tip body 3 has the above-mentioned reduced diameter portion 35, the coil liner 8 is prevented from being positioned offset relative to the inner surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner surface 31 almost evenly in the circumferential direction of the inner surface 31. This reduces offsetting of the shielding gas flow path in the internal space S, improving gas shielding during welding. As a result, improved welding quality can be expected.

In this embodiment, the reduced diameter portion 35 and the tapered portion 34 are provided at multiple locations (two locations in this embodiment) that are spaced apart from each other in the axial direction of the coil liner 8 (the vertical direction in FIG. 6). This allows the coil liner 8 to properly center with respect to the inner circumferential surface 31. This is preferable for reducing the bias of the shielding gas flow path in the internal space S and improving gas shielding during welding.

In the example shown in FIG. 6, the tip body 3 has a tapered portion 35, but for example, a tapered portion having a similar configuration to the tapered portion 35 may be provided on the inner circumferential surface 21 of the straight portion near the tip of the torch body 2.

Figures 7 and 8 show a third embodiment of the welding torch according to the present invention. In the welding torch A3 shown in Figures 7 and 8, the configuration of the tip body 3 is different from that of the welding torch A2 of the second embodiment described above.

In this embodiment, the coil liner 8 does not have a large diameter portion 81, as in the second embodiment, and has a substantially uniform outer diameter over its entire length. On the other hand, the tip body 3 has an inner protrusion 36 and a groove 37 instead of the reduced diameter portion 35 of the second embodiment.

The inner protrusions 36 are portions of the tip body 3 that protrude radially inward beyond its inner circumferential surface 31. In this embodiment, as shown in FIG. 8, multiple inner protrusions 36 are arranged at equal intervals in the circumferential direction of the tip body 3. The grooves 37 are spaces between adjacent inner protrusions 36. As shown in FIG. 7, the inner protrusions 36 of this embodiment have a longer length along the axial direction of the tip body 3 (the vertical length in the figure) than the reduced diameter portion 35 of the second embodiment.

When the tip body 3 has the above-mentioned inner protrusions 36 and grooves 37, the coil liner 8 is prevented from being positioned biased relative to the inner surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner surface 31 almost evenly in the circumferential direction of the inner surface 31. This reduces bias in the shielding gas flow path in the internal space S, improving gas shielding during welding. As a result, improved welding quality can be expected.

The inner protrusions 36 have a relatively long length along the axial direction of the tip body 3. This provides a centering effect for the coil liner 8 over a long range along the axial direction of the coil liner 8. Meanwhile, grooves 37 are formed between adjacent inner protrusions 36. This allows the shielding gas flowing through the internal space S to pass through each groove 37 between adjacent inner protrusions 36 at the locations where the inner protrusions 36 are formed. This makes it possible to suppress an increase in flow resistance of the shielding gas flow path.

In this embodiment, the inner projections 36 and the tapered portions 34 are provided at multiple locations (two locations in this embodiment) that are spaced apart from each other in the axial direction of the coil liner 8 (the vertical direction in FIG. 7). This allows the coil liner 8 to properly center with respect to the inner circumferential surface 31. This is preferable for reducing bias in the shielding gas flow path in the internal space S and improving gas shielding during welding.

In the example shown in Figures 7 and 8, the tip body 3 has an inner protrusion 36, but an inner protrusion having a configuration similar to the inner protrusion 36 may be provided on the inner circumferential surface 21 of the straight portion near the tip of the torch body 2.

Figure 9 shows a fourth embodiment of the welding torch according to the present invention. In the welding torch A4 shown in Figure 9, the configuration of the tip body 3 is different from that of the welding torch A2 of the second embodiment described above.

In this embodiment, the coil liner 8 does not have a large diameter portion 81 as in the second embodiment, and has an outer diameter that is almost uniform over the entire length. On the other hand, the chip body 3 has a press-fit portion 38 instead of the reduced diameter portion 35 of the second embodiment. The press-fit portion 38 is annular and is a portion that is pressed into the inner peripheral surface 31 of the chip body 3. Before being pressed into the chip body 3, the outer diameter of the press-fit portion 38 is slightly larger than the inner diameter of the inner peripheral surface 31. The press-fit portion 38 protrudes radially inward from the inner peripheral surface 31 of the chip body 3, and is close to or in contact with the outer periphery of the coil liner 8. The press-fit portion 38 having such a configuration corresponds to an example of an inward protruding portion (protruding portion) of the present invention.

When the tip body 3 has the above-mentioned press-fit portion 38, the coil liner 8 is prevented from being positioned biased relative to the inner surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner surface 31 almost evenly in the circumferential direction of the inner surface 31. This reduces bias in the shielding gas flow path in the internal space S, improving gas shielding during welding. As a result, improved welding quality can be expected.

In this embodiment, the press-fit portion 38 and the tapered portion 34 are provided at multiple locations (two locations in this embodiment) that are spaced apart from each other in the axial direction of the coil liner 8 (the vertical direction in FIG. 9). This allows the coil liner 8 to properly center with respect to the inner circumferential surface 31. This is preferable for reducing bias in the shielding gas flow path in the internal space S and improving gas shielding during welding.

In the example shown in FIG. 9, the press-in portion 38 is press-fitted into the inner surface 31 of the tip body 3, but for example, a press-in portion having a similar configuration to the press-in portion 38 may be press-fitted into the inner surface 21 of the straight portion near the tip of the torch body 2.

Figures 10 and 11 show a fifth embodiment of the welding torch according to the present invention. In the welding torch A5 shown in Figure 10, the specific configuration of the tip body 3 differs from that of the welding torch A4 of the fourth embodiment described above.

In this embodiment, the coil liner 8 does not have a large diameter portion 81 as in the fourth embodiment, and has an outer diameter that is almost uniform over the entire length. The chip body 3 has a press-fit portion 38 as in the fourth embodiment, but in this embodiment, the press-fit portion 38 is press-fit into the press-fit seat 39. The press-fit seat 39 is a portion that protrudes slightly radially inward from the inner peripheral surface 31 of the chip body 3. Before being pressed into the chip body 3, the outer diameter of the press-fit portion 38 is slightly larger than the inner diameter of the press-fit seat 39 and smaller than the inner diameter of the inner peripheral surface 31. The press-fit portion 38 protrudes radially inward from the inner peripheral surface 31 of the chip body 3, and is close to or in contact with the outer periphery of the coil liner 8. This press-fit portion 38 corresponds to an example of an inner protruding portion (protruding portion) of the present invention.

When the tip body 3 has the above-mentioned press-fit portion 38, the coil liner 8 is prevented from being positioned biased relative to the inner surface 31 of the tip body 3, and a gap is formed between the coil liner 8 and the inner surface 31 almost evenly in the circumferential direction of the inner surface 31. This reduces bias in the shielding gas flow path in the internal space S, improving gas shielding during welding. As a result, improved welding quality can be expected.

In this embodiment, the press-fit portion 38 and the tapered portion 34 are provided at multiple locations (two locations in this embodiment) that are spaced apart from each other in the axial direction of the coil liner 8 (the vertical direction in FIG. 10). This allows the coil liner 8 to properly center against the inner circumferential surface 31. This is preferable for reducing bias in the shielding gas flow path in the internal space S and improving gas shielding during welding.

Furthermore, in this embodiment, the press-fit portion 38 is press-fitted into a press-fit seat 39 that protrudes radially inward from the inner circumferential surface 31. With this configuration, the press-fit portion 38 can be accurately positioned at a predetermined position (the position where the press-fit seat 39 is provided).

Note that, although an example of a ring-shaped configuration of the press-in seat 39 is illustrated above, the configuration of the press-in seat 39 is not limited to this. For example, multiple press-in seats 39 separated from each other and spaced apart in the circumferential direction of the tip body 3 may be formed.

In the example shown in Figures 10 and 11, the tip body 3 has a press-in seat 39 protruding from the inner circumferential surface 31, and the press-in portion 38 is press-fitted into the press-in seat 39. However, for example, a press-in seat protruding from the inner circumferential surface 21 of the straight portion near the tip of the torch body 2 may be formed, and a press-in portion having a similar configuration to the press-in portion 38 may be press-fitted into the press-in seat.

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.

A1, A11, A12, A2, A3, A4, A5: welding torch, 2: torch body, 21: inner peripheral surface, 3: tip body, 31: inner peripheral surface, 34: tapered portion (extension portion, inner extension portion), 35: reduced diameter portion (extension portion, inner extension portion), 36: inner protrusion (extension portion, inner extension portion), 38: press-fit portion (extension portion, inner extension portion), 8: coil liner, 81: large diameter portion (extension portion, outer extension portion), S: internal space

Claims (3)

A cylindrical torch body and
A cylindrical tip body attached to the tip of the torch body;
a coil liner for passing a welding wire therethrough, the coil liner being formed by winding a metal wire in a spiral shape and being disposed in an internal space of the torch body and the tip body;
The internal space is a flow path through which a shielding gas flows,
At least one of the coil liner, the torch body, and the tip body has a protruding portion that protrudes so that the torch body or the tip body and the coil liner are closer to each other or come into contact with each other than other portions,
The protruding portion includes an inner protruding portion that protrudes radially inward from an inner peripheral surface of the torch body or the tip body,
A welding torch , wherein the inner protruding portion is a portion that is pressed into the torch body or the tip body . The welding torch of claim 1, wherein the overhanging portion includes an outer overhanging portion having an outer diameter larger than other portions of the coil liner. 3. The welding torch according to claim 1, wherein the protruding portion is provided at a plurality of positions spaced apart from each other in the axial direction of the coil liner.

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