Welding wire feeding device

Abstract

To provide a welding wire feed device which can stably feed a welding wire to a welding torch while suppressing complication of a control system of the welding wire feed device.SOLUTION: A welding wire feed device 5 includes: a wire extrusion unit 6 which extrudes a welding wire W of a pail pack 4 toward a welding torch 2; and a wire drawing unit 7 which draws the extruded welding wire W to the welding torch 2. The wire extrusion unit 6 has a first roller 9 and a second roller 10, which are arranged side by side in a roller diameter direction in a posture where rotary axis centers are directed in the same direction. Both the rollers 9, 10 feed the welding wire W to the wire drawing unit 7 side by rotating in mutually opposite directions while holding the welding wire W. The first roller 9 rotationally driven by a push motor 11 is configured to slide against the welding wire W when a preset prescribed load is applied in a rotation direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a welding wire feeding device for feeding a welding wire to a welding torch attached to an industrial robot or the like.

Background Art

[0002] Conventionally, a welding wire feeding device for feeding a welding wire to a welding torch of a welding robot installed in a factory or the like is known. For example, the welding wire feeding device disclosed in Patent Document 1 includes a wire extrusion unit that extrudes the welding wire wound around a spool toward the welding torch, and a wire drawing unit that draws the welding wire extruded by the wire extrusion unit into the welding torch. By the extrusion operation of the wire extrusion unit and the drawing operation of the wire drawing unit, the welding wire wound around the spool is fed to the welding torch. The extrusion operation of the wire extrusion unit is performed by controlling a push motor, while the drawing operation of the wire drawing unit is performed by controlling a pull motor. By controlling the current and voltage supplied to the pull motor, the welding wire is stably fed to the welding torch.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a welding wire feeding device such as that of Patent Document 1, since it is necessary to precisely control the current and voltage supplied to the pull motor, there is a risk that the control system becomes complicated. [[ID=3 =7]]

[0005] The present invention has been made in view of the above, and its objective is to provide a welding wire feeding device that can stably feed welding wire to a welding torch while suppressing the complexity of the control system of the welding wire feeding device. [Means for solving the problem]

[0006] To achieve the above objective, the present invention is characterized in that a roller driven by a push motor is allowed to slip relative to the welding wire while feeding the welding wire to the pull feeding unit.

[0007] Specifically, the welding wire feeding device comprises a wire extrusion unit that pushes the welding wire from a wire supply source toward a welding torch, and a wire retraction unit that retracts the welding wire extruded by the wire extrusion unit into the welding torch, and is configured to feed the welding wire from the wire supply source to the welding torch through the extrusion operation of the wire extrusion unit and the retraction operation of the wire retraction unit, and the following solutions were implemented.

[0008] In other words, the first invention comprises a wire extrusion unit comprising a first roller and a second roller arranged side by side in the radial direction of the rollers with their rotational axes facing the same direction, and a push motor that rotationally drives at least one of the first and second rollers, wherein the first and second rollers are configured to grip the welding wire and feed it to the wire pull-in unit by rotating in opposite directions to each other, and at least one of the first and second rollers that is rotationally driven by the push motor is configured to slide against the welding wire when a predetermined load is applied in the rotational direction.

[0009] The second invention is characterized in that, in the first invention, the wire extrusion unit is provided with a biasing member that biases the second roller toward the first roller.

[0010] In the third invention, the wire extrusion unit in the second invention comprises a case for housing the first and second rollers, and a swing arm whose one end rotatably supports the second roller and whose other end is directly or indirectly swingably supported by the case, wherein the biasing member biases the swing arm in a direction that brings the second roller closer to the first roller.

[0011] The fourth invention is characterized in that, in the third invention, the other end of the swing arm is positioned upstream of one end of the swing arm in the direction of feeding the welding wire.

[0012] The fifth invention is characterized in that, in the third or fourth invention, the wire extrusion unit is provided with an adjustment unit that can adjust the swing angle of the swing arm.

[0013] The sixth invention is characterized in that, in any one of the first to fifth inventions, the first roller is rotationally driven by the push motor, and the contact surface of the first roller with the welding wire is subjected to a low-friction treatment such that the coefficient of friction is lower than that of other parts of the first roller.

[0014] The seventh invention is characterized in that, in any one of the first to sixth inventions, the rotational speed of the push motor is set to a higher rotational speed than that of the pull motor provided in the wire pulling unit. [Effects of the Invention]

[0015] In the first invention, for example, when the amount of welding wire pulled in by the wire retraction unit toward the welding torch is relatively small, the rotational movement of the first and second rollers of the wire extrusion unit pushes the welding wire toward the wire retraction unit, resulting in an excess of welding wire between the wire retraction unit and the wire extrusion unit. This creates resistance when feeding the welding wire from the wire extrusion unit toward the wire retraction unit, i.e., feeding resistance occurs. At this time, the rotating rollers begin to slip relative to the welding wire, and the amount of welding wire extruded from the wire extrusion unit toward the wire retraction unit decreases by the amount of this slip. As a result, for example, in a relatively simple control system where the push motor only controls the switching between starting and stopping, simply driving the push motor will cause the welding wire to be pushed out from the push extrusion unit toward the wire retraction unit in accordance with the amount of extrusion corresponding to the above-mentioned feeding resistance, i.e., the amount of welding wire pulled in by the wire retraction unit toward the welding torch. Therefore, it is possible to provide a welding wire feeding device that can stably feed welding wire to a welding torch while suppressing the complexity of the control system caused by precisely controlling pull motors and the like, as is the case with welding wire feeding devices such as the one described in Patent Document 1.

[0016] In the second invention, for example, when the amount of welding wire pulled into the welding torch side in the wire retraction unit is relatively small, and the feeding resistance when feeding the welding wire from the wire extrusion unit to the wire retraction unit side is relatively large, the clamping force of the welding wire generated by the second roller biased toward the first roller by the biasing member and the first roller decreases in proportion to the feeding resistance, and the rotationally driven roller slides relative to the welding wire. Therefore, the welding wire can be stably fed to the wire retraction unit side while appropriately sliding the rotationally driven roller relative to the welding wire.

[0017] In the third invention, when the second roller is biased toward the first roller by a biasing member, for example, by biasing the second roller in a direction perpendicular to the welding wire feeding direction, it is possible to prevent a situation in which the position of the second roller and the position of the first roller are misaligned in the welding wire feeding direction, making it impossible to properly clamp the welding wire between the two rollers.

[0018] In the fourth invention, when the welding wire is fed by the first and second rollers, the second roller is caused to swing downstream in the direction of the welding wire feeding by the fed welding wire. Therefore, it is possible to suppress excessive clamping force on the welding wire by the first and second rollers, and the rotationally driven rollers can be properly slid relative to the welding wire.

[0019] In the fifth invention, for example, if the type of welding wire is changed by replacing the wire supply source, the adjustment unit can adjust the swing angle of the swing arm to an appropriate angle, thereby making the clamping force of the welding wire by the first roller and the second roller appropriate.

[0020] In the sixth invention, when the welding wire is fed to the wire pulling unit, the low-friction treated portion of the first roller and the welding wire will slide reliably, thus avoiding situations in which the rotationally driven first roller cannot slide properly relative to the welding wire.

[0021] In the seventh invention, when the rotational speed of the pull motor in the wire drawing unit is relatively high, that is, even when the amount of wire drawn by the pull motor toward the welding torch side is relatively large, a push motor that rotates at a higher rotational speed than the pull motor is used to extrude a large amount of welding wire from the wire extrusion unit toward the wire drawing unit side. Therefore, it is possible to avoid a situation where the extrusion amount from the wire extrusion unit to the wire drawing unit side is insufficient, a feeding resistance occurs when the wire drawing unit feeds the welding wire to the welding torch side, and the welding wire cannot be stably fed from the wire drawing unit to the welding torch.

Brief Description of Drawings

[0022] [Figure 1] FIG. 8 is a schematic front view of a welding system to which a welding wire feeding device according to an embodiment of the present invention is applied. [Figure 2] FIG. 11 is a schematic front view showing a main part of a welding wire feeding device according to an embodiment of the present invention. [Figure 3] FIG. 14 is a schematic right side view showing a main part of a welding wire feeding device according to an embodiment of the present invention.

[0023] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature.

[0024] FIG. 1 shows a welding system 1 to which a welding wire feeding device according to an embodiment of the present invention is applied. The welding system 1 is applied to a welding process for, for example, performing MIG welding or TIG welding between a plurality of parts in a factory or the like, and includes a welding robot 3 that performs welding using a welding torch 2, a payoff pack 4 in which a welding wire W is wound and stored, and a welding wire feeding device 5 that feeds the welding wire W of the payoff pack 4 to the welding torch 2.

[0025] The welding robot 3 comprises a base portion 3a placed on the ground and an arm portion 3b attached to the upper part of the base portion 3a and having multiple joints, and the welding torch 2 is attached to the tip of the arm portion 3b.

[0026] The pail pack 4 is installed on the ground and comprises a cylindrical housing portion 4a capable of accommodating welding wire W, and a tapered cover portion 4b attached to the upper part of the housing portion 4a. A first hole portion 4d (see Figures 2 and 3) is provided in the center of the upper end portion 4c of the cover portion 4b, which penetrates in the vertical direction.

[0027] The welding wire feeding device 5 includes a wire extrusion unit 6 that pushes the welding wire W wound and stored in the pail pack 4 toward the welding torch 2, and a wire retraction unit 7 that pulls the welding wire W pushed out by the wire extrusion unit 6 into the welding torch 2. The wire extrusion unit 6 and the wire retraction unit 7, and the wire retraction unit 7 and the welding torch 2 are connected by a conduit cable 8, each having an insertion hole 8a through which the welding wire W can be inserted. In other words, the welding wire W is fed from the pail pack 4 to the welding torch 2 through the insertion hole 8a of the conduit cable 8 by the extrusion operation of the wire extrusion unit 6 and the retraction operation of the wire retraction unit 7. In this embodiment, the wire retraction unit 7 is supported in the middle of the arm portion 3b of the welding robot 3 and is configured to pull the welding wire W into the welding torch 2 by a pair of pull feeding rollers 7a that are rotationally driven by a pull motor 7b.

[0028] Next, the wire extrusion unit 6 will be described in detail using Figures 2 and 3. In this embodiment, the upper side of Figure 2 is the upper side of the wire extrusion unit 6, the lower side is the lower side of the wire extrusion unit 6, the right side is the right side of the wire extrusion unit 6, and the left side is the left side of the wire extrusion unit 6. Similarly, the upper side of Figure 3 is the upper side of the wire extrusion unit 6, the lower side is the lower side of the wire extrusion unit 6, the right side is the rear side of the wire extrusion unit 6, and the left side is the front side of the wire extrusion unit 6.

[0029] As shown in Figure 2, the wire extrusion unit 6 is mounted on the upper part of the cover portion 4b of the pail pack 4. The wire extrusion unit 6 comprises a pair of first rollers 9 and second rollers 10, a push motor 11 connected to the first roller 9, a swing arm 12 that rotatably supports the second roller 10, a biasing member 13 that biases the swing arm so that the second roller 10 approaches the first roller 9, an adjustment unit 14 that can adjust the swing angle of the swing arm 12, and a case 6a that houses the first roller 9, the second roller 10, the push motor 11, the swing arm 12, the biasing member 13, and the adjustment unit 14.

[0030] As shown in Figure 3, case 6a has a roughly U-shaped cross-section that opens to the front, and is composed of an upper wall 6b and a lower wall 6c that are arranged opposite each other in the vertical direction, and a rear wall 6d that extends vertically to connect the rear ends of the upper wall 6b and the lower wall 6c.

[0031] The upper wall 6b is provided with a second hole 6e that penetrates the upper wall 6b vertically and through which the insertion hole 8a for the conduit cable 8 is connected. In addition, a third hole 6f that penetrates the lower wall 6c vertically is provided at a position corresponding to the second hole 6e in the lower wall 6c.

[0032] A cylindrical member 15 is fixed to the lower surface of the lower wall 6c in a position extending vertically. The cylindrical member 15 is provided with a male threaded portion 15a on its outer circumference and a fourth hole 15b which is connected to the third hole 6f of the lower wall 6c and through which the welding wire W can be inserted. With the cylindrical member 15 inserted through the first hole 4d of the pail pack 4, the wire extrusion unit 6 is attached to the cover portion 4b of the pail pack 4 by screwing together a pair of first nuts 16a and second nuts 16b, each having a female thread that can be screwed into the male threaded portion 15a of the cylindrical member, so as to clamp the upper end portion 4c of the pail pack 4 from both the vertical and horizontal sides.

[0033] In this configuration, the insertion hole 8a of the conduit cable 8 is connected to the second hole 6e of the wire extrusion unit 6, and the wire extrusion unit 6 is attached to the cover portion 4b of the pail pack 4 via the cylindrical member 15. In this configuration, the insertion hole 8a of the conduit cable 8, the second hole 6e of the upper wall 6b, the third hole 6f of the lower wall 6c, and the fourth hole 15b of the cylindrical member 15 are substantially aligned in the vertical direction, allowing the welding wire W to pass through each hole and the internal region of the case 6a in the vertical direction.

[0034] The first roller 9 is positioned inside the case 6a on the upper wall 6b side and to the right of the welding wire W. As shown in Figure 3, the outer circumferential surface 9a of the first roller 9 is provided with a first circumferential groove 9b that extends around the entire circumference at the center of the roller axial direction and is recessed radially inward to correspond to the size and shape of the welding wire W, and outer surfaces 9c provided on both sides of the first circumferential groove 9b in the roller axial direction. The first circumferential groove 9b constitutes the contact surface with the welding wire W, and is treated with a low-friction coating (for example, coated with fluororesin, diamond-like carbon, chromium, nickel, etc.) so that the coefficient of friction of the contact surface is lower than that of the surface of the outer surface 9c (the surface that does not come into contact with the welding wire W).

[0035] As shown in Figure 3, the push motor 11 is fixed to the rear wall 6d of the case 6a with its output shaft 11a extending to the front of the case 6a.

[0036] The first roller 9 is rotatably connected to the output shaft 11a of the push motor 11, and by supplying power to the push motor 11 to rotate the output shaft 11a, the first roller 9 is driven to rotate.

[0037] In this embodiment, the wire extrusion unit 6 and the wire retraction unit 7 are connected to each other so as to be able to send and receive control signals. When the wire extrusion unit 6 receives a start signal from the wire retraction unit 7, for example, a signal indicating the drive state of the pull motor 7b, it simultaneously starts driving the push motor 11. Conversely, when the wire extrusion unit 6 receives a stop signal from the wire retraction unit 7, for example, a signal indicating the stop state of the pull motor 7b, it simultaneously stops driving the push motor 11. The rotational speed of the push motor 11 is set to be higher than that of the pull motor 7b of the wire retraction unit 7 (for example, the lower limit rotational speed of the push motor 11 is set to be higher than the upper limit rotational speed of the pull motor 7b).

[0038] The second roller 10 is arranged side by side in the radial direction of the roller with the first roller 9, in a position where their rotational axes face the same direction. On the outer circumferential surface 10a of the second roller 10, in the portion corresponding to the first circumferential groove 9b of the first roller 9, there is a second circumferential groove 10b that is recessed radially inward to accommodate the size and shape of the welding wire W, and the welding wire W is sandwiched between the second circumferential groove 10b and the first circumferential groove 9b of the first roller 9.

[0039] The oscillating arm 12 is composed of a pair of first arms 12a and second arms 12b, and is arranged inside the case 6a such that one end of each arm is in an upward position and the other end of each arm is in a downward position. In this embodiment, the feeding direction of the welding wire W corresponds to the vertical direction, with the upstream side of the feeding direction being downward and the downstream side of the feeding direction being upward.

[0040] A first support shaft 10g is fixed between the first end 12c of the first arm 12a and the second end 12e of the second arm 12b in a position extending in the front-rear direction, and the first support shaft 10g rotatably supports the second roller 10.

[0041] Meanwhile, a second support shaft 10h is pivotally fixed between the first other end 12d of the first arm 12a and the second other end 12f of the second arm 12b in a position extending in the front-rear direction, and the second support shaft 10h is pivotably supported on a first support portion 17a that protrudes from the upper surface and left end of the lower wall 6c. As a result, the swinging arm 12 (first arm 12a and second arm 12b) can swing with the second support shaft 10h as the pivot center in a first swinging direction in which the second roller 10 approaches the first roller 9, or in a second swinging direction in which the second roller 10 moves away from the first roller 9.

[0042] A second support portion 17b is provided to the right of the first support portion 17a and to the left of the welding wire W, fixed to the upper surface of the lower wall 6c. A biasing member 13 (for example, an elastic member such as a compression coil spring) is stretched between the second support portion 17b and the swing arm 12, and this biasing member 13 biases the swing arm 12 to swing in the first swing direction, that is, to bring the second roller 10 closer to the first roller 9. Due to the biasing force of this biasing member 13, a force (clamping force) is generated between the first circumferential groove 9b of the first roller 9 and the second circumferential groove 10b of the second roller 10 that clamps the welding wire W in the left-right direction. As shown in Figure 2, when the swinging arm 12 swings in the first swinging direction and one end of the swinging arm 12 (first end 12c, second end 12e) is located to the right of the other end (first other end 12d, second other end 12f), the gripping force of the welding wire W is also generated when the second roller 10 leans against the first roller 9 due to the weight of the second roller 10, etc.

[0043] A third support portion 17c is provided protruding from the upper surface of the lower wall 6c between the first support portion 17a and the second support portion 17b. The third support portion 17c extends upward from the upper surface of the lower wall 6c and then extends in a way that inclins upward and to the right.

[0044] An adjustment part 14 capable of adjusting the swing angle of the swing arm 12 is attached to the third support part 17c. The adjustment part 14 consists of a third nut 14a and a screw 14b. The third nut 14a has a female screw hole and is fixed to the right side of the inclined portion of the third support part 17c. The screw 14b has a shaft portion 14c with a male screw that can be screwed into the female screw hole of the third nut 14a, and a head portion 14d provided continuously at one end of the shaft portion 14c. The other end of the shaft portion 14c is positioned to contact the right side of the swing arm 12 when the swing arm 12 is biased in the first swing direction by the biasing member 13. For convenience, the biasing member 13, the third nut 14a, the screw 14b, the second support part 17b, and the third support part 17c are not shown in Figure 3.

[0045] Here, for example, if the head 14d is rotated to one side to screw the screw 14b into the third nut 14a, the other end of the shaft 14c pushes the right side of the swing arm 12 to the left, causing the swing arm 12 to swing in the second swing direction, and the second roller 10 to move away from the first roller 9, thereby reducing the clamping force of the welding wire W by the first roller 9 and the second roller 10. On the other hand, if the head 14d is rotated to the other side to screw the screw 14b into the third nut 14a, the biasing force of the biasing member 13 causes the swing arm 12 to swing in the first swing direction, and the second roller 10 to move closer to the first roller 9, thereby increasing the clamping force of the welding wire W by the first roller 9 and the second roller 10.

[0046] Next, the operation and effects of the welding wire feeding device 5 according to this embodiment will be described.

[0047] In the wire extrusion unit 6, when the first roller 9 is rotated by the push motor 11 while the welding wire W is held between the first roller 9 and the second roller 10, the first roller 9 and the second roller 10 rotate in opposite directions to each other, thereby feeding the welding wire W toward the wire pull-in unit 7, that is, toward the conduit cable 8, which is the downstream side in the feeding direction.

[0048] When the wire extrusion unit 6 operates, the wire retraction unit 7 also operates simultaneously. The wire retraction unit 7 uses a pair of pull-feed rollers 7a, which are rotationally driven by a pull motor 7b, to retract the welding wire W extruded by the wire extrusion unit 6 into the welding torch 2.

[0049] Here, if the amount of welding wire W pulled in by the wire pull-in unit 7 toward the welding torch 2 is relatively small, the amount of welding wire W pushed out toward the wire pull-in unit 7 by the rotational movement of the first roller 9 and second roller 10 of the wire push-out unit 6 will be greater than the amount pulled in by the wire pull-in unit 7. In other words, there will be an excess of welding wire W between the wire push-out unit 6 and the wire pull-in unit 7, so feeding resistance will occur when feeding the welding wire W from the wire push-out unit 6 toward the wire pull-in unit 7. As this feeding resistance increases, the load on the push motor 11 that drives the first roller 9, which rotates to push out the welding wire W, will increase.

[0050] In response to this increase in load, in this embodiment, when the load on the push motor 11 exceeds a predetermined motor load, that is, when a predetermined load is applied to the first roller 9 that directly contacts the welding wire W in the rotational direction of the first roller 9, the clamping force of the welding wire W by the first roller 9 and the second roller 10, and the friction coefficient of the first circumferential groove 9b of the first roller 9 are set so that the first roller 9 slides against the welding wire W. In other words, the biasing force of the biasing member 13 is set so that a clamping force is generated that allows the first roller 9 to slide against the welding wire W at the predetermined load, and the first circumferential groove 9b of the first roller 9 is subjected to a low-friction treatment so that the friction coefficient is such that the first roller 9 slides against the welding wire W. As a result, when a predetermined load is applied to the first roller 9 that directly contacts the welding wire W in the rotational direction of the first roller 9, the first roller 9 slides against the welding wire W, and the amount of welding wire W extruded from the wire extrusion unit 6 to the wire retraction unit 7 is reduced by the amount of this sliding.

[0051] Therefore, for example, in a relatively simple control system in which the push motor 11 controls only the switching between starting and stopping, simply driving the push motor 11 will cause the welding wire W to be pushed out from the wire extrusion unit 6 to the wire pull-in unit 7 in accordance with the amount of extrusion corresponding to the feeding resistance described above, that is, the amount of welding wire W pulled in to the welding torch 2 side by the wire pull-in unit 7. From the above, it is possible to provide a welding wire feeding device 5 that can stably feed the welding wire W to the welding torch 2 while suppressing the complexity of the control system that would result from precisely controlling a pull motor or the like, as in a welding wire feeding device such as the one described in Patent Document 1.

[0052] Furthermore, for example, if the amount of welding wire W pulled into the welding torch 2 side by the wire pull-in unit 7 is relatively small, and the feeding resistance when feeding the welding wire W from the wire push-out unit 6 to the wire pull-in unit 7 side is relatively large, the clamping force of the welding wire W generated by the second roller 10 biased toward the first roller 9 by the biasing member 13 and the first roller 9 decreases in proportion to the feeding resistance, and the rotationally driven first roller 9 begins to slide relative to the welding wire W. Therefore, the welding wire W can be stably fed to the wire pull-in unit 7 side while appropriately sliding the rotationally driven first roller 9 relative to the welding wire W.

[0053] Furthermore, when the biasing member 13 biases the second roller 10 toward the first roller 9, for example, by biasing the second roller 10 in a direction perpendicular to the feeding direction of the welding wire W (in this embodiment, the left-right direction), it is possible to prevent a situation in which the position of the second roller 10 and the position of the first roller 9 are misaligned in the feeding direction of the welding wire W, making it impossible to properly clamp the welding wire W between the two rollers.

[0054] Furthermore, when the welding wire W is fed by the first roller 9 and the second roller 10, the second roller 10 swings downstream (upward in this embodiment) in the feeding direction of the welding wire W due to the fed welding wire W. Therefore, it is possible to suppress excessive clamping force on the welding wire W by the first roller 9 and the second roller 10, and the rotationally driven first roller 9 can be appropriately slid relative to the welding wire W.

[0055] Furthermore, for example, if the type of welding wire W is changed by replacing the pail pack 4, the adjustment unit 14 can adjust the swing angle of the swing arm 12 to an appropriate angle, thereby making the clamping force of the welding wire W by the first roller 9 and the second roller 10 appropriate.

[0056] Furthermore, since the first circumferential groove 9b of the first roller 9 is treated with a low-friction process, if the feeding resistance of the welding wire W increases when feeding the welding wire W to the wire pull-in unit 7, the first circumferential groove 9b of the first roller 9 and the welding wire W will reliably slip, thus avoiding a situation where the rotationally driven first roller 9 cannot properly slide relative to the welding wire W.

[0057] Furthermore, even when the rotational speed of the pull motor 7b in the wire retraction unit 7 is relatively high, that is, when the amount of welding wire W retracted towards the welding torch 2 by the pull motor 7b is relatively large, the push motor 11, which rotates at a higher rotational speed than the pull motor 7b, will push out a large amount of welding wire W from the wire extrusion unit 6 towards the wire retraction unit 7. Therefore, it is possible to avoid a situation where the amount of wire extrusion from the wire extrusion unit 6 towards the wire retraction unit 7 is insufficient, causing feeding resistance when the wire retraction unit 7 feeds the welding wire W towards the welding torch 2, and preventing a stable supply of welding wire W from the wire retraction unit 7 to the welding torch 2.

[0058] In this embodiment, the first circumferential groove 9b of the first roller 9 was subjected to a low-friction treatment. However, this can be replaced by appropriately setting the biasing force of the biasing member 13, thereby eliminating the need for such a friction treatment.

[0059] Furthermore, in this embodiment, the first circumferential groove 9b of the first roller 9 was subjected to a low-friction treatment so that its coefficient of friction was lower than that of the outer surface portion 9c. However, instead, the first circumferential groove 9b of the first roller 9 may be subjected to a low-friction treatment so that its coefficient of friction is lower than that of the side surface of the first roller 9 or the second circumferential groove 10b of the second roller 10.

[0060] Furthermore, in this embodiment, only the first roller 9 is driven by the push motor 11, but the push motor 11 may drive both the first roller 9 and the second roller 10, or the system may be equipped with push motors that drive the first roller 9 and the second roller 10 independently.

[0061] Furthermore, in this embodiment, the rotational speed of the push motor 11 was set to a higher rotational speed than that of the pull motor 7b, but the rotational speed of the push motor 11 may be lower than that of the pull motor 7b.

[0062] Furthermore, in this embodiment, the swing arm 12 was indirectly supported by the case 6a via the first support portion 17a, but it may also be directly supported by the case 6a (for example, the lower wall 6c or the rear wall 6d).

[0063] Furthermore, in the embodiment of the present invention, the feeding direction of the welding wire W was set to the vertical direction, but it may also be set to the left-right direction, the front-back direction, or a direction inclined with respect to these directions. [Industrial applicability]

[0064] The present invention is suitable for a welding wire feeding device that supplies welding wire to a welding torch attached to an industrial robot or the like. [Explanation of Symbols]

[0065] 2 Welding torch 4. Pail pack (wire supply source) 5. Welding wire feeding device 6 Wire extrusion unit 7 Wire pull-in unit 7b Pull motor 9. First Roller 9b First circumferential groove (contact surface with welding wire) 10. Second Laura 11 Push motor 12. Swivel Arm 13. Biasing member 14 Adjustment section W welding wire

Claims

1. A welding wire feeding device comprising a wire extrusion unit that pushes welding wire from a wire supply source toward a welding torch, and a wire retraction unit that retracts the welding wire extruded by the wire extrusion unit into the welding torch, wherein the welding wire is fed from the wire supply source to the welding torch by the extrusion operation of the wire extrusion unit and the retraction operation of the wire retraction unit, The wire extrusion unit comprises a first roller and a second roller arranged side by side in the radial direction of the rollers with their rotational axes facing the same direction, and a push motor that rotates at least one of the first and second rollers, and the first and second rollers are configured to grip the welding wire and feed it to the wire retraction unit by rotating in opposite directions to each other. At least one of the first and second rollers, which is rotationally driven by the push motor, is configured to slide against the welding wire when a predetermined load is applied in the rotational direction. The wire extrusion unit is provided with a biasing member that biases the second roller toward the first roller. The wire extrusion unit comprises a case for housing the first and second rollers, and a swing arm whose one end rotatably supports the second roller and whose other end is directly or indirectly swingably supported by the case. The biasing member biases the swinging arm in the direction that the second roller approaches the first roller. A welding wire feeding device characterized in that the wire extrusion unit is provided with an adjustment unit capable of adjusting the swing angle of the swing arm.

2. In the welding wire feeding device according to Claim 1, A welding wire feeding device characterized in that the other end of the swinging arm is positioned upstream of one end of the swinging arm in the direction of feeding the welding wire.

3. In the welding wire feeding device according to claim 1 or 2, The first roller is rotationally driven by the push motor, and A welding wire feeding device characterized in that the contact surface of the first roller with the welding wire is subjected to a low-friction treatment such that the coefficient of friction is lower than that of other parts of the first roller.

4. In a welding wire feeding device according to any one of claims 1 to 3, A welding wire feeding device characterized in that the rotational speed of the push motor is set to a higher rotational speed than that of the pull motor provided in the wire pulling unit.

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