Welding wire feeding device

Abstract

The present invention provides a welding wire feeding device that suppresses the formation of unintended current paths in the shock sensor. [Solution] The welding wire feeding device feeds welding wire to the welding site and comprises a shock sensor and a swing shaft 804 electrically connected thereto, a nozzle holder 801 fixed to the swing shaft 804, a relay wire, and insulating parts 802 and 803. One end of the relay wire is electrically connected to the nozzle holder 801, and the other end is electrically connected to a member located upstream of the shock sensor in the direction in which the welding wire is fed. The insulating parts 802 and 803 are interposed between the nozzle holder 801 and the swing shaft 804. The welding current is supplied to the nozzle holder 801 through the relay wire. The nozzle holder 801 and the swing shaft 804 are electrically insulated by the insulating parts 802 and 803.

Description

Technical Field

[0001] The present invention relates to a welding wire feeding device.

Background Art

[0002] When performing welding using a robot hand, in order to feed a welding wire to the welding location, a welding wire feeding device with a welding nozzle attached to the tip side is used.

[0003] It is necessary to transmit a welding current to the welding nozzle. This welding current is transmitted to the welding nozzle through the robot hand and relayed by the welding wire feeding device. Therefore, the welding wire feeding device is provided with a power transmission path for transmitting the welding current to the welding nozzle.

[0004] In one form of the welding wire feeding device, a part of the power transmission path is constituted by a relay wire provided so as to bypass the shock sensor. By suppressing the welding current from passing through the shock sensor in this way, it is possible to prevent the shock sensor from generating heat unintentionally or causing a spark between the shock sensor and the cables laid around it.

[0005] Examples of documents disclosing such a welding wire feeding device include Japanese Unexamined Patent Application Publication No. 2009-034698 (Patent Document 1) and Japanese Unexamined Patent Application Publication No. 2009-034746 (Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In one embodiment of the welding wire feeding device described above, the welding current is transmitted via the power transmission path to the nozzle holder and then to the welding nozzle fixed to the nozzle holder. However, a portion of the welding current transmitted to the nozzle holder may flow back towards the shock sensor located on the opposite side of the nozzle holder from the welding nozzle. This is because the nozzle holder, the shock sensor, and most of the components of the welding wire feeding device assembled between them are made of conductive materials. If a portion of the welding current flows back in this manner, it may induce unintended overheating or sparking in the shock sensor.

[0008] Therefore, the present invention has been made to solve the above-mentioned problems and aims to provide a welding wire feeding device in which the formation of unintended current paths in the shock sensor is suppressed. [Means for solving the problem]

[0009] The welding wire feeding device according to the present invention feeds welding wire to a welding site. The welding wire feeding device according to the present invention comprises a shock sensor, a swing shaft, a nozzle holder, a relay wire, and an insulating part. The swing shaft is electrically connected to the shock sensor. The nozzle holder is fixed to the swing shaft. One end of the relay wire is electrically connected to the nozzle holder, and the other end is electrically connected to a member located upstream of the shock sensor in the direction in which the welding wire is fed. The insulating part is interposed between the nozzle holder and the swing shaft. The welding current is supplied to the nozzle holder through the relay wire. The nozzle holder and the swing shaft are electrically insulated from each other by the insulating part.

[0010] By configuring it in this way, it is possible to suppress the formation of unintended current paths in the shock sensor.

[0011] In the welding wire feeding device according to the present invention described above, the nozzle holder may have a cylindrical portion. The insulating portion may include an insulating ring and an insulating bush. The insulating ring may be provided with a first slit extending along the axial direction of the cylindrical portion. The insulating bush may be provided with a second slit extending along the axial direction. The nozzle holder may be fixed to the swing shaft such that the swing shaft, insulating ring, insulating bush, and cylindrical portion are positioned in this order from the inside to the outside in the radial direction of the cylindrical portion. The first slit and the second slit may be arranged in positions that do not overlap each other in the circumferential direction of the cylindrical portion.

[0012] This configuration prevents the formation of a gap between the nozzle holder and the swing shaft where conductive materials such as welding wire debris can accumulate. As a result, it suppresses the formation of a current path that would cause the welding current to flow backward from the nozzle holder to the swing shaft.

[0013] In the welding wire feeding device according to the present invention described above, a first projection may be provided on the outer circumferential surface of the insulating ring at a position that does not overlap with the first slit in the circumferential direction. The first projection may be engaged with the second slit.

[0014] By configuring it in this way, the insulating ring can be positioned at a predetermined circumferential position relative to the insulating bush.

[0015] In the welding wire feeding device according to the present invention described above, the cylindrical portion may be provided with a third slit extending along the axial direction. The outer circumferential surface of the insulating bush may be provided with a second projection at a position that does not overlap with the second slit in the circumferential direction. The second projection may engage with the third slit.

[0016] By configuring in this way, the insulating bush can be arranged at a predetermined position in the circumferential direction with respect to the cylindrical portion.

Advantages of the Invention

[0017] According to the present invention, it becomes possible to provide a welding wire feeding device in which an unintended current-carrying path is suppressed from being formed in the shock sensor.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram showing the overall configuration of a welding nozzle and a welding wire feeding device attached to a robot arm. [Figure 2] It is a perspective view showing the overall configuration of the welding wire feeding device according to the embodiment. [Figure 3] It is a side view showing the overall configuration of the welding wire feeding device according to the embodiment. [Figure 4] It is a side view showing the state where the opening / closing cover according to the embodiment is opened. [Figure 5] It is a first perspective view showing the state where the opening / closing cover according to the embodiment is opened. [Figure 6] It is a second perspective view showing the state where the opening / closing cover according to the embodiment is opened. [Figure 7] It is a perspective cross-sectional view showing the internal configuration of the welding wire feeding device according to the embodiment. [Figure 8] It is a perspective view showing the structure around the nozzle holder according to the embodiment. [Figure 9] It is a perspective view of the insulating bush according to the embodiment. [Figure 10] It is a perspective view of the insulating ring according to the embodiment. [Figure 11] It is a schematic cross-sectional view of the swing shaft, nozzle holder, insulating bush, and insulating ring according to the embodiment. [Figure 12] It is a first perspective perspective view showing the internal configuration of the welding wire feeding device according to the embodiment. [Figure 13] It is a second perspective perspective view showing the internal configuration of the welding wire feeding device according to the embodiment. [Figure 14] This is a third perspective view showing the internal configuration of the welding wire feeding device according to the embodiment. [Figure 15] This is a fourth perspective view showing the internal configuration of the welding wire feeding device according to the embodiment. [Modes for carrying out the invention]

[0019] The welding wire feeding device of this embodiment will be described below with reference to the drawings. In the embodiments described below, when referring to the number, quantity, etc., the scope of the present invention is not necessarily limited to that number, quantity, etc., unless otherwise specified. The same reference numeral will be used for the same part or equivalent part, and redundant explanations will not be repeated. It is intended from the outset that the configurations in the embodiments will be used in appropriate combinations.

[0020] (Welding wire feeding device 1) Referring to Figures 1 to 3, the welding wire feeding device 1 of this embodiment will be described. In the following description, the downstream side in the direction (X direction) in which the welding wire 4 is fed may be referred to as the front side, and the upstream side may be referred to as the rear side. When the X direction is referred to as the front-rear direction, the direction intersecting this front-rear direction may be referred to as the lateral direction.

[0021] Referring to Figure 1, a welding nozzle 2 for feeding welding wire to the welding site is attached to the front of the welding wire feeding device 1. A robot arm 3 is connected to the rear of the welding wire feeding device 1.

[0022] Referring to Figures 2 and 3, the welding wire feeding device 1 is a device that feeds welding wire 4 to the area to be welded. The welding wire feeding device 1 comprises a housing 100 through which the welding wire 4 can be inserted from the rear to the front end, and a housing area R1 (see Figure 4) that houses a welding wire feeding mechanism that contacts the welding wire 4 and feeds the welding wire 4 to the area to be welded. The housing 100 constitutes the outer shell of the welding wire feeding device 1, including the hood 101 and motor cover 102 described later.

[0023] The front of the housing 100 is provided with a nozzle holder 801, which includes a welding nozzle mounting section 801a (see Figure 8) for mounting the welding nozzle 2. The rear of the housing 100 is provided with a robot arm mounting section 110 for connecting to the robot arm 3.

[0024] The housing 100 includes an opening / closing cover 130 that covers the containment area R1. The opening / closing cover 130 has a cover rotation support portion 132 on its rear side, which has an opening / closing central axis a1 extending in a direction intersecting the direction in which the welding wire 4 is fed. The opening / closing cover 130 is provided on the housing 100 so as to be able to open and close with the opening / closing central axis a1 as the opening / closing center. A locking mechanism 140A is provided on the front side of the opening / closing cover 130 between it and the housing 100. The opening / closing cover 130 may be made of a transparent material so that the containment area R1 is visible from the outside, or it may be made of an opaque material so that the containment area R1 is not visible from the outside.

[0025] In this way, by positioning the opening / closing central axis a1 of the opening / closing cover 130 on the rear side of the opening / closing cover 130, the storage area R1 can be opened up significantly, and the lateral side of the bottom surface 111, which will be described later, can be opened up significantly to the outside.

[0026] Referring to Figures 4 to 6, the state in which the opening / closing cover 130 is opened to the rear of the housing 100 will be described.

[0027] The containment area R1 includes a flat bottom surface 111, and the welding wire feeding mechanism M1 is placed on the bottom surface 111.

[0028] The containment area R1 is positioned at a predetermined distance from the bottom surface 111 in the X direction from which the welding wire 4 is fed, and includes a first wall 112 located on the upstream (rear) side in the X direction from which the welding wire 4 is fed, and a second wall 113 located on the downstream (front) side in the X direction from which the welding wire 4 is fed. The bottom surface 111 is open to the outside in the lateral direction (perpendicular to the plane of the paper in Figure 4) that intersects with the direction from which the welding wire 4 is fed.

[0029] The shape of the recessed storage area R1, defined in a side view by the bottom surface 111, the first wall 112, and the second wall 113, is matched to the shape of the cover edge 134 of the opening / closing cover 130. As a result, when the opening / closing cover 130 is closed to the housing 100, the storage area R1 can be completely covered by the opening / closing cover 130.

[0030] The locking mechanism 140A, provided between the opening / closing cover 130 and the housing 100, locks the opening / closing cover 130 to the housing 100 when the locking claws 135 and 136 provided on the opening / closing cover 130 engage with the locking member 140.

[0031] A first inclined wall 112c is provided between the bottom surface 111 and the first wall 112, extending in a direction intersecting the X direction from which the welding wire 4 is fed. A second inclined wall 113c is provided between the bottom surface 111 and the second wall 113, extending in a direction intersecting the X direction from which the welding wire 4 is fed.

[0032] The welding wire feeding mechanism M1, positioned on the flat bottom surface 111, includes at least a drive roller 400 that contacts the welding wire 4, and a pressure roller 320 that, together with the drive roller 400, grips the welding wire 4. The drive roller 400 is driven by a drive mechanism provided on the bottom surface 111 and inside the housing 100. The pressure roller 320 is provided on a pressure arm 300. The pressure arm 300 includes a rotating arm 310. One end of the rotating arm 310 is provided with an arm rotation support shaft 330 that rotatably supports the rotating arm 310 relative to the bottom surface 111. The support rotation axis c1 of the arm rotation support shaft 330 is positioned substantially perpendicular to the bottom surface 111.

[0033] The rotating arm 310 is equipped with the aforementioned pressure roller 320 in its central position, and a lock groove 310m is provided on the side of the rotating arm 310 opposite the arm rotation support shaft 330, flanking the pressure roller 320. This lock groove 310m is used to lock the welding wire 4 in place between the pressure roller 320 and the drive roller 400.

[0034] A lock pin 200, including an adjustment screw 210 that engages with a lock groove 310m, is provided on the first wall 112. The lock pin 200 includes the adjustment screw 210 and a spring case 220 that provides elastic force in the axial direction of the adjustment screw 210. The spring case 220 is rotatably supported on the first wall 112 with respect to a case rotation support 230 provided on the first wall 112. The case rotation axis b1 is an axis that extends perpendicular to the first wall 112 and is the same as the X direction in which the welding wire 4 is fed.

[0035] An inlet wire guide 500 is provided on the first wall 112, and an outlet wire guide 600 is provided on the second wall 113. The welding wire 4 is fed from the inlet wire guide 500 toward the outlet wire guide 600. The welding wire 4 is held between the pressure roller 320 and the drive roller 400 in the region between the inlet wire guide 500 and the outlet wire guide 600.

[0036] Figure 5 shows the state in which the pressure arm 300 is locked by the lock pin 200. The clamping force on the welding wire 4 by the pressure roller 320 and the drive roller 400 can be changed by adjusting the elastic force of the spring provided in the spring case 220.

[0037] Figure 6 shows the state in which the lock on the pressurizing arm 300 is released by the lock pin 200. By rotating the adjustment screw 210 along the case rotation axis b1, the adjustment screw 210 is released from the lock groove 310m. As a result, the rotating arm 310 becomes rotatable along the support rotation axis c1 of the arm rotation support shaft 330.

[0038] (Internal configuration of welding wire feeding device 1) The internal configuration of the welding wire feeding device 1 will be described with reference to Figures 7 to 11. Figure 11 is a schematic cross-sectional view along the line XI-XI in Figure 8. A plug body 810 is provided on the robot arm mounting portion 110 side of the first wall 112 via a first insulating wall 115. A power supply block 811 is fixed to the plug body 810. A first wire passage 810a is provided in the plug body 810, and a second wire passage 115a is provided in the first insulating wall 115. The first wire passage 810a and the second wire passage 115a are in communication with the inlet wire guide 500.

[0039] A drive motor 700 that drives the drive roller 400 is located in the area of ​​the bottom surface 111 opposite to the housing area R1. A second insulating wall 116 is located between the bottom surface 111 and the drive motor 700. The drive motor 700 is covered by a motor cover 102, and the other internal equipment is completely covered by a hood 101.

[0040] Viewed from the outlet wire guide 600 mounted on the second wall 113, the nozzle holder 801 is arranged in the following order on its side: coil spring 806, swing shaft 804, and nozzle holder 801. A spring guide 805 is mounted on the outer circumferential surface of the coil spring 806. A sensor (not shown) is provided near the coil spring 806. These coil spring 806, spring guide 805, and sensor constitute a shock sensor. The side of the swing shaft 804 where the coil spring 806 is located is fixed to the swing shaft so that the swing shaft 804 can swing by a swing shaft bearing 807.

[0041] The component interposed between the coil spring 806 and the swing shaft 804 is made of a conductive material. This electrically connects the shock sensor and the swing shaft 804. Furthermore, the aforementioned power supply block 811 is located upstream of the shock sensor in the direction from which the welding wire 4 is fed.

[0042] The welding wire 4, fed out from the outlet wire guide 600, passes through the inside of the coil spring 806, the swing shaft 804, and the nozzle holder 801.

[0043] On the side of the swing shaft 804 opposite to the coil spring 806, a substantially cylindrical nozzle holder 801 is fixed via a cylindrical insulating ring 803 and an insulating bush 802. In this embodiment, the insulating ring 803 and insulating bush 802 correspond to the insulating part.

[0044] As shown in Figures 7, 10, and 11, the insulating ring 803 has a substantially cylindrical shape. When the insulating ring 803 is assembled to the nozzle holder 801, the insulating ring 803 is provided with a first slit 803s that extends along the axial direction of the nozzle holder 801. The first slit 803s penetrates the insulating ring 803.

[0045] When the insulating ring 803 is assembled to the nozzle holder 801, a first projection 803t extending along the axial direction is provided on the outer circumferential surface of the insulating ring 803. The first projection 803t is positioned so as not to overlap with the first slit 803s in the circumferential direction of the nozzle holder 801. In this embodiment, the first projection 803t is positioned 180° rotationally symmetric to the first slit 803s when viewed along the axial direction.

[0046] The material of the insulating ring 803 is not particularly limited as long as it is insulating. Examples of materials that can be used for the insulating ring 803 include polyetheretherketone (PEEK), polyphenylene sulfide (PPS), or polyetherimide (PEI).

[0047] As shown in Figures 7, 9, and 11, the insulating bush 802 has a substantially cylindrical shape. When the insulating bush 802 is assembled to the nozzle holder 801, the insulating bush 802 is provided with a second slit 802s that extends along the axial direction of the nozzle holder 801. The second slit 802s does not penetrate the insulating bush 802.

[0048] When the insulating bush 802 is assembled to the nozzle holder 801, a second projection 802t extending along the axial direction is provided on the outer circumferential surface of the insulating bush 802. The second projection 802t is positioned so as not to overlap with the second slit 802s in the circumferential direction of the nozzle holder 801. In this embodiment, the second projection 802t is positioned adjacent to the second slit 802s in the circumferential direction.

[0049] The material of the insulating bush 802 is not particularly limited as long as it is insulating. Examples of materials used for the insulating bush 802 include PEEK, PPS, or PEI.

[0050] As shown in Figures 7, 8, and 11, the nozzle holder 801 has a cylindrical portion. The end of this cylindrical portion located on the side opposite to the coil spring 806 constitutes the welding nozzle mounting portion 801a described above.

[0051] The cylindrical portion is provided with a third slit 801s that extends along its axial direction. The third slit 801s does not penetrate the cylindrical portion.

[0052] As shown in Figure 11, the nozzle holder 801 is fixed to the swing shaft 804 such that the swing shaft 804, insulating ring 803, insulating bush 802, and cylindrical portion are positioned in this order from the inside to the outside in the radial direction of the cylindrical portion. The outer circumferential surface of the swing shaft 804 is in contact with the inner circumferential surface of the insulating ring 803. The outer circumferential surface of the insulating ring 803 is in contact with the inner circumferential surface of the insulating bush 802. The outer circumferential surface of the insulating bush 802 is in contact with the inner circumferential surface of the cylindrical portion.

[0053] By interposing the insulating bush 802 and insulating ring 803 between the nozzle holder 801 and the swing shaft 804 in this manner, the nozzle holder 801 and the swing shaft 804 are electrically insulated from each other by the insulating bush 802 and insulating ring 803.

[0054] Furthermore, as described above, by providing slits in the nozzle holder 801, insulating bush 802, and insulating ring 803, a considerable degree of bending force is applied to each component. This bending force makes it possible to achieve a stronger fixation between the components. It is preferable that the slits be tightened with bolts or the like after the components are assembled together.

[0055] With the nozzle holder 801 fixed to the swing shaft 804, the first projection 803t of the insulating ring 803 engages with the second slit 802s of the insulating bush 802. This positions the insulating ring 803 at a predetermined circumferential position relative to the insulating bush 802. Here, the widthwise dimension of the first projection 803t is smaller than the widthwise dimension of the second slit 802s. This ensures that the aforementioned bending force of the insulating bush 802 is maintained even when the first projection 803t and the second slit 802s are engaged.

[0056] With the nozzle holder 801 fixed to the swing shaft 804, the second projection 802t of the insulating bush 802 engages with the third slit 801s of the cylindrical portion. This positions the insulating bush 802 at a predetermined circumferential position relative to the cylindrical portion. Here, the widthwise dimension of the second projection 802t is smaller than the widthwise dimension of the third slit 801s. This ensures that the aforementioned bending force of the nozzle holder 801 is maintained even when the second projection 802t and the third slit 801s are engaged.

[0057] With the nozzle holder 801 fixed to the swing shaft 804, the first slit 803s of the insulating ring 803 and the second slit 802s of the insulating bush 802 are positioned so as not to overlap each other in the circumferential direction of the cylindrical portion. In this embodiment, the first slit 803s is positioned 180° rotationally symmetric to the second slit 802s when viewed along the axial direction of the cylindrical portion.

[0058] As shown in Figure 7, when viewed along the X direction from which the welding wire 4 is fed, a wire feeding path WF is formed by at least an inlet wire guide 500, a welding wire feeding mechanism M1, an outlet wire guide 600, a coil spring 806, a bearing for a swing shaft 807, and a swing shaft 804, from which the welding wire 4 is fed. A plug body 810 and a power supply block 811 are positioned on the inlet side of the wire feeding path WF for the welding wire 4, and a nozzle holder 801 is positioned on the outlet side of the wire feeding path WF for the welding wire 4.

[0059] As described above, the welding wire feeding device 1 is equipped with a shock sensor. When an external force is applied to the welding nozzle 2 mounted on the welding nozzle mounting section 801a, the nozzle holder 801 swings together with the swing shaft 804. At this time, the swing shaft 804 absorbs the shock by compressing the coil spring 806 (shock absorber mechanism). This shock is detected by a sensor (not shown), and control is performed to stop the welding wire feeding device 1.

[0060] Referring to Figures 12 to 15, the path for supplying welding current to the welding nozzle 2 via the welding wire feeder 1 will be described. To facilitate the explanation of the internal mechanism, the hood 101 and motor cover 102 are shown in a partially transparent state.

[0061] As shown in Figure 12, the welding wire feeding device 1 of this embodiment relays the current supplied from the robot arm 3 via a power supply block 811. One end of the first relay wire E1, the second relay wire E2, the third relay wire E3, and the fourth relay wire E4 are connected to the power supply block 811. The other ends of the first relay wire E1, the second relay wire E2, the third relay wire E3, and the fourth relay wire E4 are connected to a nozzle holder 801. As a result, the welding current is supplied to the nozzle holder 801 through these relay wires. The relay wires are not limited to wires suitable for power transmission, but strand wires, for example, may be used.

[0062] This embodiment describes a case using four relay wires, but the number of wires used can be appropriately selected according to the amount of current to be transmitted, and it is preferable to use one or two or more relay wires.

[0063] Of the first relay wire E1, second relay wire E2, third relay wire E3, and fourth relay wire E4, which are routed through the gap between the hood 101 and one side of the drive motor 700, the third relay wire E3 and fourth relay wire E4 are routed toward the front side shown in the figures, as shown in Figures 13 and 14, and then connected to the nozzle holder 801. The first relay wire E1 and second relay wire E2 are routed toward the opposite side shown in the figures, as shown in Figures 13 and 15, and then connected to the nozzle holder 801.

[0064] The swing shaft bearing 807 of the swing shaft 804 is provided with a flange 807f that protrudes radially outward. This flange 807f is provided with curved first recess 807a, second recess 807b, and third recess 807c that are recessed radially inward.

[0065] In the circumferential direction of the flange 807f, the first recess 807a and the second recess 807b are located on the opposite side from the opening / closing cover 130, and the third recess 807c is located closer to the opening / closing cover 130 than the first recess 807a and the second recess 807b.

[0066] The number of recesses provided in flange 807f can be selected as appropriate, and it is preferable to have one or two or more recesses.

[0067] To facilitate the wiring of the relay wires inside the hood 101, the first relay wire E1 and the second relay wire E2 are routed inside the hood 101 so as to pass through the first recess 807a, and the third relay wire E3 and the fourth relay wire E4 are routed so as to pass through the second recess 807b. A gas pipe G1 for supplying welding gas from the robot arm 3 toward the welding nozzle 2 is routed through the third recess 807c.

[0068] As described above, in the welding wire feeding device 1 of this embodiment, the nozzle holder 801 and the swing shaft 804 are electrically insulated from each other by an insulating part. With this configuration, it is possible to prevent a portion of the welding current transmitted from the robot arm 3 to the nozzle holder 801 via each relay wire, etc., from flowing back towards the shock sensor via the swing shaft 804, etc.

[0069] As a result, it effectively suppresses the unintended overheating of the shock sensor due to reverse welding current, and prevents sparks from occurring between the shock sensor and cables routed around it.

[0070] Therefore, by using the welding wire feeding device 1 according to this embodiment, it is possible to suppress the formation of unintended current paths in the shock sensor.

[0071] Furthermore, according to the welding wire feeding device 1 described above, the first slit 803s of the insulating ring 803 and the second slit 802s of the insulating bush 802 are positioned so as not to overlap each other in the circumferential direction of the cylindrical portion of the nozzle holder 801.

[0072] This configuration makes it possible to more reliably suppress the formation of unintended current-carrying paths. When the first slit 803s and the second slit 802s are positioned to overlap each other in the circumferential direction, a gap is created between the nozzle holder 801 and the swing shaft 804 where conductive materials such as welding wire debris can accumulate. This creates a current-carrying path that causes the welding current to flow in reverse from the nozzle holder 801 to the swing shaft 804. However, by configuring it as described above, such a current-carrying path is prevented from being formed.

[0073] Furthermore, according to the welding wire feeding device 1 described above, a power supply block 811 is provided near the robot arm mounting section 110 connected to the robot arm 3, and the welding current is supplied to the nozzle holder 801 via a relay wire. As a result, the relay wire can be routed inside the housing 100, bypassing the drive motor 700. This also makes it possible to avoid the formation of unintended current paths to the drive motor 700.

[0074] Furthermore, the welding wire feeding device 1 described above allows for flexible wiring of the intermediate wire even within the complex internal structure of the housing 100, where wiring space is limited, by using an intermediate wire. As a result, the assembly work of the welding wire feeding device 1 is made more efficient, and the parts replacement work during maintenance is also made more efficient. Moreover, since commercially available products are used for the intermediate wire, there is no increase in the cost of the welding wire feeding device 1.

[0075] In conventional designs, a busbar was provided to bridge a movable shock absorber mechanism, thereby supplying welding current to the nozzle holder 801. However, in this configuration, the welding current path came close to the drive motor 700, making it highly likely that an unexpected current path would be formed in the drive motor 700. Furthermore, the busbar required the use of a highly conductive material (such as brass or copper), making the busbar itself an expensive component.

[0076] However, the welding wire feeding device 1 described above makes it possible to solve the problems of the conventional structure described above.

[0077] In the welding wire feeding device 1 described above, the example shows that the insulating part includes an insulating bush 802 and an insulating ring 803. However, the insulating part does not necessarily have to be composed of two members; it may be composed of a single member or a combination of three or more members.

[0078] Although a welding wire feeding device has been described above in the embodiments, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims, and all modifications are made within the meaning and scope of equivalents of the claims. [Explanation of Symbols]

[0079] 1 welding wire feeder, 4 welding wires, 801 nozzle holder, 801s third slit, 802 insulating bush, 802s second slit, 802t second protrusion, 803 insulating ring, 803s first slit, 803t first protrusion, 804 swing shaft.

Claims

1. A welding wire feeding device that feeds welding wire to the area to be welded, Shock sensor and, A swing shaft electrically connected to the shock sensor, A nozzle holder fixed to the swing shaft, A relay wire having one end electrically connected to the nozzle holder and the other end electrically connected to a member located upstream of the shock sensor in the direction in which the welding wire is fed, The nozzle holder and the swing shaft are interposed in an insulating portion, A welding current is supplied to the nozzle holder through the relay wire. A welding wire feeding device in which the nozzle holder and the swing shaft are electrically insulated from each other by the insulating part.

2. The nozzle holder has a cylindrical portion, The insulating part includes an insulating ring and an insulating bush, The insulating ring is provided with a first slit that extends along the axial direction of the cylindrical portion. The insulating bush is provided with a second slit extending along the axial direction, The nozzle holder is fixed to the swing shaft such that the swing shaft, the insulating ring, the insulating bush, and the cylindrical portion are positioned in this order from the inside to the outside in the radial direction of the cylindrical portion. The welding wire feeding device according to claim 1, wherein the first slit and the second slit are arranged in positions that do not overlap each other in the circumferential direction of the cylindrical portion.

3. A first projection is provided on the outer circumferential surface of the insulating ring at a position that does not overlap with the first slit in the circumferential direction. The welding wire feeding device according to claim 2, wherein the first projection is engaged with the second slit.

4. The cylindrical portion is provided with a third slit extending along the axial direction. A second projection is provided on the outer circumferential surface of the insulating bush at a position that does not overlap with the second slit in the circumferential direction. The welding wire feeding device according to claim 2 or 3, wherein the second projection is engaged with the third slit.

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