Wire feeding device, arc welding apparatus, and wire feeding method

Abstract

To perform a wire feeding operation according to welding conditions by switching the feeding operation of a first wire and the feeding operation of a second wire.SOLUTION: The first feeding roller 42 and the second feeding roller 46 are rotationally driven by one driving motor 50. The first switching mechanism 70 switches between a first state in which the first pressure roller 43 is pressed against the first feeding roller 42 and a second state in which the first pressure roller 43 is separated from the first feeding roller 42. The second switching mechanism 75 switches between a first state in which the second pressure roller 47 is pressed against the second feeding roller 46 and a second state in which the second pressure roller 47 is separated from the second feeding roller 46.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a wire feeding device, an arc welding device, and a wire feeding method. [Background technology]

[0002] Patent Document 1 discloses a dual-wire welding system including a first wire (first consumable material), a second wire (second consumable material), and a tip that applies a welding current to the first wire and the second wire.

[0003] In the invention of Patent Document 1, when the first wire and the second wire are fed to the welding position, the tips of the first wire and the second wire are melted to form a bridge droplet between them. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7220533 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in order to form a bridge droplet, a large welding current is required, so when the welding current is small, it is necessary to feed only one of the first wire and the second wire to the welding position.

[0006] However, in order to feed only one of the first wire or the second wire, it is necessary to stop the wire feeding device and then remove the first wire or the second wire from the tip, which results in a problem of the wire feeding device being down for a long time and reducing productivity.

[0007] The present invention has been made in consideration of these points, and its purpose is to enable wire feeding operations to be performed according to welding conditions by switching between feeding operations of a first wire and feeding operations of a second wire. [Means for solving the problem]

[0008] A first invention is a wire feeding device that feeds a first wire and a second wire to a predetermined welding position, and includes a first wire feeding unit having a first feed roller that feeds the first wire and a first pressure roller that sandwiches the first wire between the first feed roller and the first feed roller, a second wire feeding unit having a second feed roller that feeds the second wire and a second pressure roller that sandwiches the second wire between the second feed roller and the second feed roller, a drive motor that drives the first feed roller and the second feed roller to rotate, a first switching mechanism that switches between a first state in which the first pressure roller is pressed against the first feed roller and a second state in which the first pressure roller is separated from the first feed roller, and a second switching mechanism that switches between the first state in which the second pressure roller is pressed against the second feed roller and the second state in which the second pressure roller is separated from the second feed roller.

[0009] In the first aspect of the present invention, by switching between the feeding operation of the first wire and the feeding operation of the second wire, it is possible to perform the wire feeding operation according to the welding conditions.

[0010] Specifically, when the welding current is increased to bridge the tip of the first wire and the tip of the second wire to form a bridge droplet, the first switching mechanism is switched to the first state and the second switching mechanism is switched to the first state, whereby the first feed roller and the second feed roller can feed the first wire and the second wire to the welding position simultaneously.

[0011] On the other hand, when the welding current is small and cannot be bridged between the first wire and the second wire, for example, by switching the first switching mechanism to the first state and the second switching mechanism to the second state, the first feed roller can feed only the first wire to the welding position.

[0012] Alternatively, the first switching mechanism may be switched to the second state and the second switching mechanism may be switched to the first state, so that only the second wire is fed to the welding position by the second feed roller.

[0013] A second aspect of the present invention is the wire feeder of the first aspect, further comprising an angle detector that detects a rotation angle of the drive motor.

[0014] In the second aspect of the present invention, the angle detector detects the rotation angle of the drive motor, thereby making it possible to adjust the feed amounts of the first wire and the second wire.

[0015] A third invention is an arc welding apparatus including the wire feeding device of the first or second invention, and a welding torch that generates an arc between at least one of the first wire and the second wire, which are consumable electrodes fed from the wire feeding device, and a workpiece to weld the workpiece. The welding torch includes a first feed path through which the first wire fed from the first wire feeder passes, and a second feed path through which the second wire fed from the second wire feeder passes. The welding torch has a torch body, a torch tip end provided at the tip side of the torch body, one internal feed path provided inside the torch body and the torch tip end, a tip that is located further tip-side than the internal feed path and supplies power to at least one of the first wire and the second wire, and a junction portion provided at the base end of the torch body and that causes the first wire that has passed through the first feed path and the second wire that has passed through the second feed path to join so as to pass through the internal feed path.

[0016] In the third invention, the first wire that has passed through the first feed path and the second wire that has passed through the second feed path are merged to pass through a single internal feed path, so there is no need to provide a feed path dedicated to the first wire and a feed path dedicated to the second wire inside the torch body and the torch tip.

[0017] A fourth invention is a wire feeding method for feeding a first wire and a second wire to a predetermined welding position, comprising the steps of: pressing a first pressure roller against a first feed roller that feeds the first wire, thereby switching between a first state in which the first wire is sandwiched between the first feed roller and the first pressure roller, and a second state in which the first pressure roller is separated from the first feed roller; and pressing a second pressure roller against a second feed roller that feeds the second wire, thereby switching between the first state in which the second wire is sandwiched between the second feed roller and the second pressure roller, and the second state in which the second pressure roller is separated from the second feed roller.

[0018] In the fourth aspect of the present invention, by switching between the feeding operation of the first wire and the feeding operation of the second wire, it is possible to perform the wire feeding operation according to the welding conditions.

[0019] A fifth invention is a wire feeding method of the fourth aspect, comprising: a double feeding step of setting the first pressure roller to the first state while setting the second pressure roller to the first state and rotating the first feed roller and the second feed roller in the forward direction to simultaneously feed the first wire and the second wire in the forward direction; a step of cutting the tip ends of the first wire and the second wire after the double feeding step is completed; a step of switching the second pressure roller in the first state to the second state and rotating the first feed roller in the first state in the reverse direction to feed only the first wire in the reverse direction so that the tip end of the second wire protrudes relatively more than the tip end of the first wire; and a single feeding step of switching the first pressure roller in the first state to the second state while switching the second pressure roller in the second state to the first state and rotating the second feed roller in the forward direction to feed only the second wire in the forward direction.

[0020] In the fifth aspect of the present invention, it is possible to switch from a double feeding operation in which the first wire and the second wire are fed forward simultaneously to a single feeding operation in which only the second wire is fed forward.

[0021] A sixth invention is a wire feeding method according to the fourth aspect, which includes a single feeding step of switching the first pressure roller to the second state while switching the second pressure roller to the first state and rotating the second feed roller in the forward direction to feed only the second wire in the forward direction; a step of switching the first pressure roller in the second state to the first state after the single feeding step is completed, while switching the second pressure roller in the first state to the second state and rotating the first feed roller in the forward direction to feed only the first wire in the forward direction so that the tip of the first wire protrudes further than the tip of the second wire; a step of cutting and aligning the tip ends of the first wire and the second wire; and a double feeding step of switching the second pressure roller in the second state to the first state and rotating the first feed roller and the second feed roller in the forward direction to feed the first wire and the second wire simultaneously in the forward direction.

[0022] In the sixth aspect of the present invention, it is possible to switch from a single feeding operation in which only the second wire is fed forward to a double feeding operation in which the first wire and the second wire are fed forward simultaneously. [Effects of the Invention]

[0023] According to the present invention, by switching between the feeding operation of the first wire and the feeding operation of the second wire, it is possible to perform the wire feeding operation according to the welding conditions. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a side view showing a configuration of an arc welding device. [Figure 2] FIG. 2 is a perspective view showing the configuration of a welding torch. [Figure 3] FIG. 2 is a side cross-sectional view showing the configuration of a welding torch. [Figure 4]FIG. 10 is a side cross-sectional view showing a state in which a bridge droplet is formed at the tip end of the first wire and the second wire. [Figure 5] FIG. 2 is a perspective view showing the configuration of a wire feeding device. [Figure 6] FIG. 4 is a side view showing the configuration of a first wire feeder. [Figure 7] FIG. 4 is a side view showing the configuration of a second wire feeder. [Figure 8] FIG. 2 is a perspective view showing the configuration of a transmission mechanism. [Figure 9] FIG. 10 is a cross-sectional side view showing a state in which a solidified ball is formed at the tip end of the first wire and the second wire. [Figure 10] FIG. 2 is a perspective view showing the configuration of a wire cutter. [Figure 11] 10 is a side cross-sectional view showing a state in which the tip of the second wire protrudes beyond the tip and the first wire is disposed within the tip. FIG. [Figure 12] 10 is a side cross-sectional view showing a state in which the tip of the first wire protrudes beyond the tip of the second wire. FIG. [Figure 13] FIG. 10 is a flowchart showing a procedure for switching from a double feeding operation to a single feeding operation. [Figure 14] FIG. 10 is a flowchart showing a procedure for switching from a single feeding operation to a double feeding operation. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0026] As shown in FIG. 1, the arc welding device 1 welds the workpiece W by generating an arc between the workpiece W and first and second wires 10 and 20, which are consumable electrodes.

[0027] The arc welding apparatus 1 includes a robot 2, a control unit 5, a first wire reel 11, a second wire reel 21, a welding torch 30, and a wire feeder 40.

[0028] A first wire 10 is wound around the first wire reel 11. The first wire 10 unwound from the first wire reel 11 is sandwiched between a first feeding roller 42 and a first pressure roller 43 in the wire feeding device 40 (see FIG. 6).

[0029] The second wire 20 is wound around the second wire reel 21. The second wire 20 unwound from the second wire reel 21 is sandwiched between a second feeding roller 46 and a second pressure roller 47 in the wire feeding device 40 (see FIG. 7).

[0030] A first feeding path 12 and a second feeding path 22 are provided between wire feeding device 40 and welding torch 30. First wire 10 fed from first wire feeding section 41 (see FIG. 5) of wire feeding device 40 passes through first feeding path 12. Second wire 20 fed from second wire feeding section 45 (see FIG. 5) of wire feeding device 40 passes through second feeding path 22.

[0031] The wire feeder 40 feeds the first wire 10 and the second wire 20 to a predetermined welding position. The wire feeder 40 feeds the first wire 10 and the second wire 20 at a predetermined feeding speed based on a signal from the control unit 5. Furthermore, based on a signal from the control unit 5, the wire feeder 40 alternately performs forward feeding, in which the first wire 10 and the second wire 20 are fed in the direction of the workpiece W, and reverse feeding, in which the first wire 10 and the second wire 20 are fed in the direction opposite to the forward feeding.

[0032] The robot 2 has a plurality of joints. A welding torch 30 is attached to the tip of the robot 2. The robot 2 moves the position of the welding torch 30 relative to the workpiece W.

[0033] Control unit 5 controls the operations of robot 2 and wire feeder 40. Control unit 5 moves welding torch 30 along the welding direction of workpiece W by providing current commands to motors (not shown) of each axis of robot 2. Control unit 5 controls the feed speed of first wire 10 and second wire 20 according to a preset set current of the welding current.

[0034] As shown in FIGS. 2 and 3, welding torch 30 has a torch body 31, a torch tip 32, one inner tube 33 (internal feed path), a junction , and a tip .

[0035] The torch body 31 is formed in a cylindrical shape. The first wire 10 and the second wire 20 pass through the inside of the torch body 31. The torch tip 32 is provided on the tip side of the torch body 31.

[0036] The inner tube 33 is provided inside the torch body 31 and the torch tip 32. The inner tube 33 is made of a coil formed by spirally winding a wire rod having a circular cross section. The first wire 10 and the second wire 20 are inserted through the inner tube 33.

[0037] The junction 34 is provided on the base end side of the torch body 31. The junction 34 merges the first wire 10 that has passed through the first feed path 12 and the second wire 20 that has passed through the second feed path 22 so that they pass through the inner tube 33.

[0038] The tip 35 is disposed inside the torch tip 32. The tip 35 is disposed closer to the tip side than the inner tube 33. The tip of the tip 35 protrudes from the torch tip 32. The tip 35 supplies power to at least one of the first wire 10 and the second wire 20.

[0039] The chip 35 is formed with a first insertion hole 36 and a second insertion hole 37. The first wire 10 is inserted through the first insertion hole 36. The second wire 20 is inserted through the second insertion hole 37.

[0040] Hereinafter, a case where the wire diameter of the first wire 10 and the second wire 20 is 0.9 mm and the distance between the first wire 10 and the second wire 20 is 0.6 mm will be described as an example.

[0041] When a large welding current (e.g., 300 A or more) is applied to the first wire 10 and the second wire 20, a bridge occurs between the first wire 10 and the second wire 20, forming a bridge droplet 15 (see FIG. 4). By performing arc welding with the bridge droplet 15 formed, the bead width can be increased.

[0042] On the other hand, when the welding current applied to the first wire 10 and the second wire 20 is small (for example, less than 300 A), no bridging occurs between the first wire 10 and the second wire 20. Therefore, when the welding current is small, it is necessary to feed only one of the first wire 10 and the second wire 20 to the welding position on the workpiece W to perform arc welding.

[0043] However, in order to feed only one of the first wire 10 and the second wire 20, it is necessary to stop the wire feeding device 40 once and then remove the first wire 10 or the second wire 20 from the tip 35, which poses a problem of increasing the downtime of the wire feeding device 40 and reducing productivity.

[0044] Therefore, in this embodiment, by switching between the feeding operation of the first wire 10 and the feeding operation of the second wire 20, it is possible to perform the wire feeding operation according to the welding conditions.

[0045] <About the wire feeder> As shown in FIG. 5, the wire feeder 40 includes a first wire feeder 41, a second wire feeder 45, one drive motor 50, a transmission mechanism 60, a first switching mechanism 70, and a second switching mechanism 75.

[0046] As shown in Fig. 6, the first wire feeder 41 has a first feed roller 42 and a first pressure roller 43. The first wire 10 is sandwiched between the first feed roller 42 and the first pressure roller 43. The first feed roller 42 feeds the first wire 10. In Fig. 6, the wire feed direction is indicated by an arrow.

[0047] As shown in Fig. 7, the second wire feeder 45 has a second feed roller 46 and a second pressure roller 47. The second wire 20 is sandwiched between the second feed roller 46 and the second pressure roller 47. The second feed roller 46 feeds the second wire 20. In Fig. 7, the wire feed direction is indicated by an arrow.

[0048] As shown in Fig. 5, the drive motor 50 drives and rotates the first feed roller 42 and the second feed roller 46. The drive motor 50 has an angle detection unit 51. The angle detection unit 51 detects the rotation angle of the drive motor 50. The angle detection unit 51 is, for example, an encoder. By detecting the rotation angle of the drive motor 50 using the angle detection unit 51, the feed amounts of the first wire 10 and the second wire 20 can be adjusted.

[0049] 8, a transmission mechanism 60 is provided between the drive motor 50 and the first and second feed rollers 42 and 46. The transmission mechanism 60 includes a first pulley 61, a second pulley 62, a transmission belt 63, a reducer 64, a first bevel gear 65, a second bevel gear 66, a transmission shaft 67, a first gear 68, and a second gear 69.

[0050] The first pulley 61 is attached to a motor shaft (not shown) of the drive motor 50. The second pulley 62 is attached to a rotating shaft (not shown) of the reducer 64. The transmission belt 63 is wound around the first pulley 61 and the second pulley 62.

[0051] The first bevel gear 65 is attached to the end of the rotation shaft of the reducer 64 opposite to the second pulley 62. The second bevel gear 66 meshes with the first bevel gear 65. The second bevel gear 66 is attached to a transmission shaft 67. The transmission shaft 67 extends in a direction perpendicular to the rotation shaft of the reducer 64. The first bevel gear 65 and the second bevel gear 66 convert the rotational driving force of the rotation shaft of the reducer 64 into the rotational driving force of the transmission shaft 67.

[0052] A first gear 68 and a second gear 69 are attached to both axial ends of the transmission shaft 67. The first gear 68 meshes with a gear portion (not shown) of the first feed roller 42, causing the first feed roller 42 to rotate. The second gear 69 meshes with a gear portion (not shown) of the second feed roller 46, causing the second feed roller 46 to rotate.

[0053] As a result, by driving and rotating one drive motor 50, the first feed roller 42 and the second feed roller 46 can be rotated synchronously via the transmission mechanism 60. Therefore, during arc welding, the first wire 10 and the second wire 20 can be fed at the same speed and timing.

[0054] As shown in Figure 6, the first switching mechanism 70 switches between a first state (shown by a solid line in Figure 6) in which the first pressure roller 43 is pressed against the first feed roller 42, and a second state (shown by a virtual line in Figure 6) in which the first pressure roller 43 is separated from the first feed roller 42.

[0055] The first switching mechanism 70 has a first roller support portion 71, a first support shaft 72, a first cylinder 73, and a first fixed portion 74. The first roller support portion 71 rotatably supports the first pressure roller 43. The first roller support portion 71 rotates around the first support shaft 72.

[0056] The first cylinder 73 is fixed to the first roller support portion 71. The tip end of the first cylinder rod 73a of the first cylinder 73 is fixed to the first fixed portion 74. The first cylinder 73 switches the first pressure roller 43 between the first state and the second state.

[0057] In the first state, the first cylinder rod 73a of the first cylinder 73 is retracted. As a result, the first roller support portion 71 rotates about the first support shaft 72 so as to reduce the distance between the first roller support portion 71 and the first fixed portion 74, and the first pressure roller 43 is pressed against the first feed roller 42.

[0058] In the first state, first wire 10 is sandwiched between first feed roller 42 and first pressure roller 43. In the first state, when first feed roller 42 is rotated by drive motor 50, first wire 10 is fed so as to protrude from tip 35 of welding torch 30.

[0059] In the second state, the first cylinder rod 73a of the first cylinder 73 is extended. As a result, the first roller support portion 71 rotates about the first support shaft 72 so that the distance between the first roller support portion 71 and the first fixed portion 74 increases, and the first pressure roller 43 moves away from the first feed roller 42.

[0060] In the second state, the first wire 10 is not sandwiched between the first feed roller 42 and the first pressure roller 43. In the second state, even if the first feed roller 42 is rotated by the drive motor 50, the first wire 10 is not fed.

[0061] As shown in Figure 7, the second switching mechanism 75 switches between a first state (shown by a solid line in Figure 7) in which the second pressure roller 47 is pressed against the second feed roller 46, and a second state (shown by a virtual line in Figure 7) in which the second pressure roller 47 is separated from the second feed roller 46.

[0062] The second switching mechanism 75 has a second roller support portion 76, a second support shaft 77, a second cylinder 78, and a second fixed portion 79. The second roller support portion 76 rotatably supports the second pressure roller 47. The second roller support portion 76 rotates around the second support shaft 77.

[0063] The second cylinder 78 is fixed to the second roller support portion 76. The tip end of a second cylinder rod 78a of the second cylinder 78 is fixed to a second fixed portion 79. The second cylinder 78 switches the second pressure roller 47 between the first state and the second state.

[0064] In the first state, the second cylinder rod 78a of the second cylinder 78 is retracted. As a result, the second roller support portion 76 rotates about the second support shaft 77 so as to reduce the distance between the second roller support portion 76 and the second fixed portion 79, and the second pressure roller 47 is pressed against the second feed roller 46.

[0065] In the second state, the second cylinder rod 78a of the second cylinder 78 is extended. As a result, the second roller support portion 76 rotates about the second support shaft 77 so that the distance between the second roller support portion 76 and the second fixed portion 79 increases, and the second pressure roller 47 moves away from the second feed roller 46.

[0066] The first state or the second state of the second switching mechanism 75 is the same as the first state or the second state of the first switching mechanism 70, and therefore the following description will be omitted.

[0067] In this way, by switching between the feeding operation of first wire 10 and the feeding operation of second wire 20, it is possible to perform a wire feeding operation according to the welding conditions.

[0068] Specifically, when the welding current is increased to bridge the tip of the first wire 10 and the tip of the second wire 20 to form bridge droplet 15, first switching mechanism 70 is switched to the first state, and second switching mechanism 75 is also switched to the first state. This allows first feed roller 42 and second feed roller 46 to simultaneously feed first wire 10 and second wire 20 to the welding position.

[0069] Furthermore, when it is desired to feed only the first wire 10 from a state in which the first wire 10 and the second wire 20 are protruding from the tip 35, the first switching mechanism 70 is switched to the second state and the second switching mechanism 75 is switched to the first state. This enables only the second wire 20 to be fed, so the second wire 20 is fed in reverse so as to be retracted into the tip 35. Thereafter, the first switching mechanism 70 is switched to the first state and the second switching mechanism 75 is switched to the second state. This causes only the first wire 10 to be fed from the tip of the welding torch 30.

[0070] Furthermore, when it is desired to feed only the second wire 20 from a state in which the first wire 10 and the second wire 20 are protruding from the tip 35, the first switching mechanism 70 is switched to the first state and the second switching mechanism 75 is switched to the second state. This enables only the first wire 10 to be fed, so the first wire 10 is fed in reverse so as to be retracted into the tip 35. Thereafter, the first switching mechanism 70 is switched to the second state and the second switching mechanism 75 is switched to the first state. This causes only the second wire 20 to be fed from the tip of the welding torch 30.

[0071] <About wire cutters> As shown in FIG. 9, when arc welding is stopped after the first wire 10 and the second wire 20 are fed simultaneously, solidified portions 16 are formed at the tip portions of the first wire 10 and the second wire 20.

[0072] Therefore, for example, even if an attempt is made to feed the first wire 10 backward so as to draw the first wire 10 into the welding torch 30, the solidified portion 16 gets in the way, and the first wire 10 ends up getting caught on the tip 35.

[0073] Therefore, in this embodiment, a wire cutter 90 is used to cut the tip portions of the first wire 10 and the second wire 20. In Fig. 9, the cutting positions of the first wire 10 and the second wire 20 are shown by virtual lines.

[0074] Specifically, as shown in FIG. 10, the wire cutter 90 has a main body case 91, a cutting part 92, and a base part 93.

[0075] An advancing / retracting mechanism (not shown), such as an air cylinder, is provided in the main body case 91. The advancing / retracting mechanism advances and retracts the cutting part 92 toward the first wire 10 and the second wire 20.

[0076] The base portion 93 is provided with a notch portion 94. The first wire 10 and the second wire 20 are inserted through the notch portion 94.

[0077] The cutting portion 92 slides along the upper surface of the base portion 93. An inclined surface 92a that slopes diagonally downward is formed on the tip side of the cutting portion 92 in the direction of movement. By inserting the first wire 10 and the second wire 20 into the notch portion 94 and sliding the cutting portion 92, the first wire 10 and the second wire 20 can be cut by the inclined surface 92a of the cutting portion 92.

[0078] <Procedure for aligning the tips of the first and second wires> As shown in FIG. 11, a procedure for aligning the tips of first wire 10 and second wire 20 from a state in which first wire 10 is drawn into welding torch 30 will be described.

[0079] 5, the first switching mechanism 70 is switched to the second state, while the second switching mechanism 75 is switched to the first state. As a result, even if the drive motor 50 is rotated, the second wire 20 is idled and only the first wire 10 is fed.

[0080] 12, the first wire 10 is fed so that the tip of the first wire 10 protrudes from the tip of the tip 35. At this time, the first wire 10 is fed to a position where the tip of the first wire 10 protrudes further forward than the tip of the second wire 20. Note that in FIG. 12, the cutting positions of the first wire 10 and the second wire 20 are indicated by imaginary lines.

[0081] 10, the first wire 10 and the second wire 20 are inserted into the notch 94 of the base 93 of the wire cutter 90, and the first wire 10 and the second wire 20 are cut by the cutting part 92. This makes it possible to align the tip ends of the first wire 10 and the second wire 20.

[0082] <Procedure for switching from double feed operation to single feed operation> Hereinafter, a procedure for switching from a double feeding operation in which the first wire 10 and the second wire 20 are fed forward simultaneously to a single feeding operation in which only the second wire 20 is fed forward will be described.

[0083] As shown in FIG. 13, in step S11, the first pressure roller 43 is set to the first state, while the second pressure roller 47 is set to the first state, and the first feed roller 42 and the second feed roller 46 are rotated forward to perform a double feed operation in which the first wire 10 and the second wire 20 are fed forward simultaneously, and then the process proceeds to step S12.

[0084] After the double feeding operation is completed, coagulated portions 16 are formed at the tip portions of the first wire 10 and the second wire 20 (see FIG. 9). In step S12, the tip portions of the first wire 10 and the second wire 20 are cut by the wire cutter 90, and the process proceeds to step S13.

[0085] In step S13, the second pressure roller 47 in the first state is switched to the second state, and the first feed roller 42 in the first state is rotated in the reverse direction to feed only the first wire 10 in the reverse direction so that the tip of the second wire 20 protrudes relatively more than the tip of the first wire 10, and the process proceeds to step S14. The tip of the first wire 10 is drawn into the tip 35 (see FIG. 11).

[0086] In step S14, the first pressure roller 43 in the first state is switched to the second state, while the second pressure roller 47 in the second state is switched to the first state, and the second feed roller 46 is rotated forward to perform a single feed operation in which only the second wire 20 is fed forward, and the process is terminated.

[0087] In this embodiment, only the second wire 20 is fed in the single feeding operation, but only the first wire 10 may be fed.

[0088] <Procedure for switching from single feed operation to double feed operation> Hereinafter, a procedure for switching from a single feeding operation in which only the second wire 20 is fed forward to a double feeding operation in which the first wire 10 and the second wire 20 are fed forward simultaneously will be described.

[0089] 14, in step S21, the first pressure roller 43 is set to the second state, while the second pressure roller 47 is set to the first state, and the second feed roller 46 is rotated forward to perform a single feed operation in which only the second wire 20 is fed forward, and then the process proceeds to step S22. In the single feed operation, the tip end of the first wire 10 is retracted into the tip 35 (see FIG. 11).

[0090] In step S22, after the single feeding operation is completed, the first pressure roller 43 in the second state is switched to the first state, while the second pressure roller 47 in the first state is switched to the second state, and the first feeding roller 42 is rotated forward to feed only the first wire 10 forward (see Figure 12) so that the tip of the first wire 10 protrudes further than the tip of the second wire 20, and then the process proceeds to step S23.

[0091] In step S23, the tip portions of the first wire 10 and the second wire 20 are cut by the wire cutter 90 to align the tip portions of the first wire 10 and the second wire 20, and the process proceeds to step S24.

[0092] In step S24, the second pressure roller 47 is switched from the second state to the first state, and the first feed roller 42 and the second feed roller 46 are rotated forward to perform a double feed operation in which the first wire 10 and the second wire 20 are fed forward simultaneously, and the process is terminated.

[0093] Other Embodiments The above embodiment may be configured as follows.

[0094] In the present embodiment, the first wire 10 and the second wire 20 have the same wire diameter, but the present invention is not limited to this. For example, if the wire diameter of the first wire 10 is 1.2 mm and the wire diameter of the second wire 20 is 0.9 mm, welding can be performed using only the first wire 10 having a wire diameter of 1.2 mm, welding using only the second wire having a wire diameter of 0.9 mm, or welding the first wire 10 and the second wire 20 simultaneously, depending on the welding current. This allows a wide range of welding to be performed using a single wire feeder 40. [Industrial Applicability]

[0095] As described above, the present invention has a highly practical effect of being able to perform wire feeding operations according to welding conditions by switching between the feeding operation of the first wire and the feeding operation of the second wire, and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0096] 1. Arc welding equipment 10 First Wire 12 1st feed route 20 Second Wire 22 2nd feed route 30 Welding Torch 31 Torch body 32 Torch tip 33 Internal feed path (inner tube) 34 Junction 35 chips 40 Wire feeder 41 First wire feeder 42 First feeding roller 43 First pressure roller 45 Second wire feeder 46 Second feeding roller 47 Second pressure roller 50 Drive motor 51 Angle detection unit 70 First switching mechanism 75 Second switching mechanism

Claims

1. A wire feeding device that feeds a first wire and a second wire to a predetermined welding position, a first wire feeding unit including a first feeding roller that feeds the first wire and a first pressure roller that sandwiches the first wire between the first feeding roller and the first pressure roller; a second wire feeding unit including a second feeding roller that feeds the second wire and a second pressure roller that sandwiches the second wire between the second feeding roller and the second pressure roller; a drive motor that rotates the first feed roller and the second feed roller; a first switching mechanism that switches between a first state in which the first pressure roller presses the first feed roller and a second state in which the first pressure roller is spaced apart from the first feed roller; a second switching mechanism that switches between a first state in which the second pressure roller presses the second feed roller and a second state in which the second pressure roller is spaced apart from the second feed roller. Wire feeder.

2. The wire feeder of claim 1, An angle detection unit is provided to detect the rotation angle of the drive motor. Wire feeder.

3. The wire feeder of claim 1 or 2; an arc welding apparatus including: at least one of the first wire and the second wire, which are consumable electrodes fed from the wire feeder; and a welding torch that generates an arc between the first wire and the second wire and a workpiece to weld the workpiece; a first feeding path through which the first wire fed from the first wire feeding unit passes; a second feeding path through which the second wire fed from the second wire feeding unit passes, The welding torch is a torch body; a torch tip portion provided on the tip side of the torch body portion; an internal feed path provided inside the torch body and the torch tip; a tip disposed distal to the internal feed path and supplying power to at least one of the first wire and the second wire; a junction portion provided on a base end side of the torch body portion, which joins the first wire that has passed through the first feed path and the second wire that has passed through the second feed path so that they pass through the internal feed path. Arc welding equipment.

4. A wire feeding method for feeding a first wire and a second wire to a predetermined welding position, comprising: a step of switching between a first state in which a first pressure roller is pressed against a first feed roller that feeds the first wire, and the first wire is sandwiched between the first pressure roller and the first feed roller, and a second state in which the first pressure roller is separated from the first feed roller; and a step of switching between a first state in which a second pressure roller is pressed against a second feed roller that feeds the second wire, and the second wire is sandwiched between the second pressure roller and the second feed roller, and a second state in which the second pressure roller is separated from the second feed roller. Wire feeding method.

5. The wire feeding method according to claim 4, a double feeding step of setting the first pressure roller in the first state while setting the second pressure roller in the first state, and rotating the first feed roller and the second feed roller in the forward direction to feed the first wire and the second wire simultaneously; a step of cutting the tip portions of the first wire and the second wire after the double feeding step is completed; switching the second pressure roller in the first state to the second state and rotating the first feed roller in the first state in reverse, thereby feeding only the first wire in reverse so that a tip end of the second wire protrudes relatively more than a tip end of the first wire; a single feeding step of switching the first pressure roller in the first state to the second state, while switching the second pressure roller in the second state to the first state, and rotating the second feed roller in the forward direction to feed only the second wire in the forward direction. Wire feeding method.

6. The wire feeding method according to claim 4, a single feeding step of setting the first pressure roller in the second state while setting the second pressure roller in the first state, and rotating the second feed roller in the forward direction to feed only the second wire in the forward direction; after the single feeding step is completed, switching the first pressure roller from the second state to the first state, while switching the second pressure roller from the first state to the second state, and rotating the first feed roller in the forward direction to feed only the first wire in the forward direction so that a tip end of the first wire protrudes further than a tip end of the second wire; cutting and aligning the tip portions of the first wire and the second wire; a double feeding step of switching the second pressure roller in the second state to the first state and rotating the first feed roller and the second feed roller in the forward direction to feed the first wire and the second wire simultaneously in the forward direction. Wire feeding method.

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