Welding Systems

Abstract

This welding system comprises: a tip having, on the tip thereof, a forced power feed mechanism which biases a welding wire and feeds power to the welding wire; a torch which has the tip on the distal end thereof and supplies the welding wire toward a welding position; an automatic apparatus that holds the torch; and a welding wire correction apparatus which is attached to the automatic apparatus and corrects the bending tendency of the welding wire.

Description

[Technical field]

[0001] The present disclosure relates to a welding system. [Background technology]

[0002] Patent Document 1 discloses a welding tip for consumable gas-shielded arc welding in which an insulating guide is provided at the tip of the power feed tip. The welding tip for consumable gas-shielded arc welding comprises a power feed tip, an insulating guide located at the tip of the power feed tip, and a guide holder detachably connected to the tip of the power feed tip. The power feed tip is detachably connected to the tip of the welding torch body and supplies current to the welding wire passing through a welding wire insertion hole formed in the center. The insulating guide guides the welding wire that has passed through the power feed tip toward the material to be welded, and keeps the welding wire protruding from the power feed tip long. The guide holder holds the insulating guide at the tip of the power feed tip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-112261 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a welding system that more effectively suppresses misalignment of a welding point even when the extension length of a welding wire is increased. [Means for solving the problem]

[0005] The present disclosure provides a welding wire straightening machine that includes a tip having a forced power supply mechanism at its tip for energizing a welding wire and supplying power to the welding wire, a torch having the tip at its tip and supplying the welding wire toward a welding point, an automated machine that holds the torch, and a welding wire straightening machine that is attached to the automated machine and straightens out any bending of the welding wire.the welding wire straightening machine straightens the welding wire protruding from the tip, the automatic machine performs welding in a position in which the welding wire has a bending angle of less than 180° and a bending radius of 150 mm or more in at least a part of a feeding path of the welding wire between a supply source of the welding wire and the torch, and the automatic machine further includes a connection part connected to the feeding path and a connection unit fixing the connection part to the automatic machine, the connection unit having a mechanism for rotating the connection unit itself. A welding system is provided. Effect of the Invention

[0006] According to the present disclosure, even if the extension length of the welding wire is increased, it is possible to more effectively suppress misalignment of the welding point. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an external side view of a welding robot according to a first embodiment; [Diagram 2] FIG. 13 is a perspective view of a main part of a welding robot in which a second feed path is bent [Diagram 3] Perspective view of the connection unit [Figure 4] FIG. 2 is a perspective view of the connection unit with the cover member removed; [Diagram 5] FIG. 1 is a diagram illustrating a bend release structure of a flexible conduit in a second feeding path by a connection unit. [Figure 6] Plan view of the second connection part [Figure 7] Cross section AA shown in Figure 6 [Figure 8] FIG. 13 is a perspective view of a main part of a second connection portion [Figure 9] Plan view of the first connection part [Figure 10] Enlarged plan view of the first connection part [Figure 11] FIG. 1 is a perspective view showing an example of a bearing mechanism; [Figure 12] Enlarged view of the main part of the torch neck [Figure 13] Correlation table of bending angle and bending radius of torch neck with curvature radius Φ=1200 or more [Figure 14] FIG. 1 is an external side view of a welding robot according to a modification of the first embodiment. [Figure 15] Principle diagram of HEAT welding [Figure 16] A diagram explaining examples of misalignment of welding points DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (Background to this disclosure) In conventional arc welding methods, the welding robot keeps the distance between the power feed tip and the welding wire (the extension length of the welding wire) longer than usual, and increases the Joule heat applied to the welding wire in proportion to the extension length, thereby increasing the amount of melted welding wire even with the same welding current. However, the welding wire wound around a pack, spool, etc. has a curl and a certain curvature. Therefore, when the welding robot increases the extension length of the welding wire, the curl of the welding wire itself can cause a large positional deviation (off-target) of the welding point.

[0009] Furthermore, there is a conventional welding robot that performs HEAT welding by providing an insulating guide using a ceramic material at the tip of a power feed tip to prevent misalignment of a welding point. Hereinafter, HEAT welding performed by a welding robot equipped with an insulating guide will be described with reference to Figs. 15 and 16.

[0010] Fig. 15 is a diagram showing the principle of HEAT welding. For ease of understanding, the forced power supply tip 15 (see Fig. 1) is omitted from the tip 95 shown in Fig. 15.

[0011] HEAT welding is a type of welding that can increase the amount of deposition of the welding wire 13 by increasing the amount of heat (Joule heat) applied to the welding wire 13 at the same current value. The formula for calculating Joule heat W is W = I0 × V0 = I0 × (I0 · R0) = I0 2 ×R0.

[0012] A welding robot that performs HEAT welding can increase the amount of melting of welding wire 13 by increasing the Joule heat applied to welding wire 13 due to the resistance value R0 that increases in proportion to extension lengths D1, D2 of welding wire 13, thereby improving welding efficiency. As shown in FIG. 15, the resistance value R0 of welding wire 13 is greater at extension length D2 than at extension length D1. However, such a welding robot has a problem that the positional deviation (off-target) of the welding point increases due to the large extension length, as shown in FIG. 16. Therefore, conventional welding robots have been provided with an insulating guide at the tip end to reduce the off-target caused by the bending tendency of welding wire 13.

[0013] Fig. 16 is a diagram for explaining an example of misalignment of a welding point. For ease of understanding, the forced power supply tip 15 (see Fig. 1) is omitted from the tip 95 shown in Fig. 16.

[0014] 16, even if the welding robot performs welding by aligning the position of tip 95 with the welding point (position Pt0), the welding point may be misaligned (off-target) due to the bending tendency of welding wire 13.

[0015] Furthermore, the insulating guide is made of a ceramic material to improve heat resistance during welding, so tips equipped with insulating guides have problems such as high material costs and the welding wire softened by power supply becoming clogged or fused to the inner diameter portion of the insulating guide.

[0016] Hereinafter, with reference to the drawings as appropriate, each embodiment specifically disclosing the welding system according to the present disclosure will be described in detail. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0017] First, an overview of a welding robot 11 will be described with reference to Fig. 1. Fig. 1 is an external side view of the welding robot 11 according to the first embodiment.

[0018] The welding robot 11 according to the first embodiment is an example of a welding system, and includes a forced power feed tip 15, a torch 19, a manipulator 17, and a welding wire straightener .

[0019] Forced-power tip 15, as an example of a tip, has a forced-power mechanism (not shown) that mechanically urges welding wire 13 toward the welding point and supplies power to welding wire 13. Torch 19 is equipped with forced-power tip 15 at its tip, and supplies welding wire 13 from the tip of forced-power tip 15 toward the welding point on the welding base material. Manipulator 17, as an example of an automatic machine, holds torch 19. Welding wire straightener 21 is attached to manipulator 17, and straightens out any bending tendency of welding wire 13 that is supplied toward the tip of torch 19 from wire supply source 33, as an example of a supply source.

[0020] The welding robot 11 is configured using a base section (not shown) that is installed on a production line (not shown), a rotating section (not shown) that is attached to the top of the base section and rotates horizontally, and a manipulator 17. The manipulator 17 is configured using an upper arm section 25 that is attached to the rotating section and swings back and forth, a forearm section 27 that is attached to the upper arm section 25 and swings up and down, a wrist section 29 that is attached to the forearm section 27 and has three-dimensional degrees of freedom, and the like. In addition to the upper arm section 25, the forearm section 27, the wrist section 29, and the like, the manipulator 17 may also include an automatic transport facility that can transport the welding robot 11.

[0021] The welding robot 11 controls the posture of the torch 19 attached to the wrist 29 by the movement of each part, such as the base part, the rotating part, the upper arm part 25, and the forearm part 27, thereby performing arc welding (HEAT welding) on ​​the welding base material in any posture.

[0022] Welding robot 11 according to embodiment 1 has welding wire feed motor 31 above torch 19 (i.e., on the torch 19 side) and has welding wire straightener 21 on the wire supply source 33 side. Welding wire feed motor 31 draws welding wire 13 from wire supply source 33 and feeds welding wire 13 from wire supply source 33 toward the tip of torch 19.

[0023] In addition, while welding is being performed, welding wire feeding motor 31 alternately performs an operation of feeding (supplying) welding wire 13 in the forward direction toward the tip of torch 19 and an operation of feeding (retrieving) welding wire 13 in the reverse direction from the tip of torch 19 at high speed.

[0024] Welding wire feed motor 31 performs forward and reverse feed operation of welding wire 13, for example, at a cycle of 7 to 10 mm, about 140 times per second. Note that the stroke length and cycle speed of welding wire 13 in the forward and reverse feed operation described above are merely examples, and needless to say, are not limited to these.

[0025] Here, torch 19 in the first embodiment performs welding while feeding welding wire 13 forward and backward at high speed using welding wire feeding motor 31. Welding robot 11 needs a feeding path (second feeding path 39) that can allow for a return allowance (extra length) (e.g., 7 to 10 mm) of welding wire 13 during reverse feeding.

[0026] The welding wire 13 is fed from a wire supply source 33 to the torch 19 through a feed path. The feed path is composed of a first feed path 35 and a second feed path 39. The first feed path 35 connects the wire supply source 33 and the welding wire straightener 21. The second supply path 39 connects the connection unit 37 and the torch 19. In this embodiment, the term "feed path" is used as a general term for the first feed path 35 and the second feed path 39.

[0027] The first feeding path 35, which is connected to the wire supply source 33, is connected to the welding wire straightener 21 by a first connection part 41. The welding wire straightener 21 is connected to a connection unit 37. The connection unit 37 is connected to a second feeding path 39 by a second connection part 43.

[0028] The second feeding path 39 is formed of, for example, a flexible conduit, and the welding wire 13 is inserted inside the flexible conduit. The second feeding path 39 is connected to each of the second connecting portion 43 and the third connecting portion 45 to form the second feeding path 39. The flexible conduit is a guide tube through which the welding wire 13 can be smoothly inserted.

[0029] The third connection portion 45 is connected to the torch 19. The welding wire 13 is fed from inside the torch 19 toward the welding point, and is melted by being fed with electricity by a forced power feed mechanism inside the torch 19, and is welded to the welding base material.

[0030] In addition, in this embodiment 1, the welding robot 11 is described as an example in which the second feed path 39 is configured using a flexible conduit, but the entire feed path (each of the first feed path 35 and the second feed path 39) may be configured using a flexible conduit.

[0031] The welding wire 13 is fed from the tip of the torch 19 toward the base material to be welded in a substantially straight state after the bending tendency has been corrected by the welding wire straightener 21. The welding robot 11 controls the attitude of the manipulator 17 so as to suppress bending of the second feed path 39 so as not to cause excessive bending of the welding wire 13 passing through the second feed path 39.

[0032] The welding robot 11 controls the posture of the manipulator 17 so that the welding wire 13 is bent at an angle of less than 180° and at a bend radius of 150 mm or more in the second feed path 39. The welding robot 11 also includes a mechanism capable of releasing (opening) bending, twisting, etc. of the second feed path 39.

[0033] FIG. 3 is a perspective view of the connection unit 37. As shown in FIG.

[0034] In the connection unit 37, a base plate portion 49 of a base block 47 is fixed to the manipulator 17. In the base block 47, a second connection portion 43 (see FIG. 1) as an example of a connection portion is covered with a cover member 51 and supported by a rotatable mechanism such as a bearing.

[0035] 1, the welding wire straightener 21 is connected to the upstream side of the connection unit 37 in the feeding direction of the welding wire 13. In addition, a second feeding path 39 is connected to the downstream side of the second connection portion 43 in the feeding direction of the welding wire 13.

[0036] Next, a release mechanism for the welding wire 13 in the second feed path 39 by the connection unit 37 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a perspective view of the connection unit 37 from which the cover member 51 has been removed. Fig. 5 is a view illustrating a bending release structure of the flexible conduit in the second feed path 39 by the connection unit 37.

[0037] The connection unit 37 is configured using a second connection part 43 and a unit body 63. The second connection part 43 is configured using a plug 75A and a coupler 77A. The unit body 63 is configured using a base block 47, a pan bearing 53, a pan bracket 55, and a tilt bearing 61.

[0038] The plug 75A fixes the flexible conduit to the second connection portion 43. The coupler 77A connects the flexible conduit to the plug 75A so as to be rotatable in a rotation direction S (see FIG. 6).

[0039] The base block 47 supports a pan bracket 55 via a pan bearing 53. The pan bearing 53 has a rotation center perpendicular to the base plate portion 49, and supports the pan bracket 55 rotatably in the pan direction P about this rotation center.

[0040] Pan bracket 55 is supported by pan bearing 53 at horizontal plate portion 57 formed in a substantially L-shaped metal fitting. Second connection portion 43 is supported on vertical plate portion 59 of pan bracket 55 via tilt bearing 61. Tilt bearing 61 supports second connection portion 43 rotatably in tilt direction T about a rotation center perpendicular to the rotation center of pan bearing 53.

[0041] The pan bearing 53 and the tilt bearing 61 form a rotating mechanism. The connection unit 37 supports the second connection portion 43 of the flexible conduit rotatably in the pan direction P and the tilt direction T via this rotating mechanism.

[0042] The pan bearing 53 rotates in the pan direction P, thereby allowing the direction of the second connection portion 43 to rotate in the pan direction P. This allows the welding robot 11 to adjust the direction of the second connection portion 43 when the bending angle of the welding wire 13 in the second feed path 39 is less than 180° and the bending radius is less than 150 mm depending on the posture of the manipulator 17.

[0043] The tilt bearing 61 rotates in the tilt direction T, thereby enabling forward and reverse feeding of the welding wire 13 between the first feeding path 35 and the second feeding path 39. In other words, the tilt bearing 61 can control the wire length of the welding wire 13 in the first feeding path 35 (i.e., the path length of the first feeding path 35) and the wire length of the welding wire 13 in the second feeding path 39 (i.e., the path length of the second feeding path 39).

[0044] Specifically, when the flexible conduit is bent following the movement of the manipulator 17, if the bending radius R1 is less than 150 mm, the connection unit 37 tilts in a direction to release the bending radius R1 of the flexible conduit (i.e., in a direction to recover the flexible conduit toward the wire supply source 33) by the tilt bearing 61. This causes the bending radius of the welding wire 13 to change from R1 to R2, and the bending radius of the welding wire 13 in the second feeding path 39 can be maintained at R2=150 mm or more.

[0045] 5 has been described as an example of releasing the welding wire 13 from the bending radius R1 to the bending radius R2, the method of releasing the welding wire 13 is not limited thereto. For example, the welding robot 11 may feed the welding wire 13 toward the torch 19 side so that a plurality of different bent portions having a bending angle of less than 180° and a bending radius of 150 mm or more are formed in the welding wire 13 in the second feeding path 39. In such a case, the welding robot 11 may use a combination of a method of releasing the twist of the welding wire 13 using a bearing mechanism described in FIG. 6 and a method of releasing the bend of the welding wire 13 using a tilt bearing 61.

[0046] As a result, when the bending angle of the welding wire 13 in the second feed path 39 is less than 180° or the bending radius is less than 150 mm due to the attitude of the manipulator 17 or the forward and reverse feed operation of the welding wire 13 by the welding wire feed motor 31, the welding robot 11 can adjust the length of the welding wire 13 in the second feed path 39 by the tilt bearing 61. Therefore, the welding robot 11 can more effectively prevent the welding wire 13 from becoming bent at a bending angle of less than 180° or a bending radius of less than 150 mm in the second feed path 39, causing the welding wire 13 to become bent.

[0047] A release mechanism for the welding wire 13 in the second feed path 39 will be described with reference to Fig. 2. Fig. 2 is a perspective view of a main part of the welding robot 11 in which the second feed path 39 is bent.

[0048] The welding robot 11 includes a connection unit 37 on the back portion of the manipulator 17 (specifically, the connection portion between the upper arm portion 25 and the forearm portion 27). The connection unit 37 connects the first feed path 35 and the second feed path 39. The connection unit 37 holds a second connection portion 43 of the second feed path 39, and rotates around the axis of the flexible conduit in accordance with the bending of the second feed path 39, thereby releasing the bending of the second feed path 39.

[0049] As a result, the welding robot 11 can release the bend in the welding wire 13 at the second feed path 39, thereby controlling the attitude of the manipulator 17 so that the welding wire 13 does not become bent.

[0050] Next, a release mechanism for releasing the twist of the welding wire 13 in the second feed path 39 will be described with reference to Fig. 6. Fig. 6 is a plan view of the second connection portion 43.

[0051] The welding robot 11 includes a bearing mechanism rotatable about the axis of the welding wire 13 as a second mechanism for releasing the bending (twist) of the welding wire 13 in the second feeding path 39. The bearing mechanism is provided, for example, at the second connection portion 43 of the second feeding path 39, and releases the twist of the welding wire 13 by rotating in the rotation direction S.

[0052] As a result, the welding robot 11 can more effectively prevent the welding wire 13 from being bent at an angle of less than 180° or a bending radius of less than 150 mm in the second feed path 39, resulting in the welding wire 13 becoming bent due to twisting.

[0053] FIG. 7 is a cross-sectional view taken along line AA shown in FIG.

[0054] The bearing mechanism in the second connection portion 43 is realized by a ball bearing, a roller bearing 65, or the like. FIG. 7 shows a roller bearing 65 as an example. The roller bearing 65 includes an inner cylinder portion 67 and an outer cylinder portion 71 rotatably assembled to the outer diameter side of the inner cylinder portion 67 via a plurality of rollers 69. A flexible conduit is fixed to the inner cylinder portion 67. The plurality of rollers 69 are held by a cage. The outer cylinder portion 71 is fixed to the connection unit 37 by a screw 73.

[0055] When the welding wire 13 of the second feed path 39 is twisted, the inner cylinder portion 67 of the roller bearing 65 rotates relative to the outer cylinder portion 71 fixed to the connection unit 37. The flexible conduit is twisted in the rotation direction S as a result of the inner cylinder portion 67 rotating in the rotation direction S.

[0056] This allows the welding robot 11 to release the twist in the welding wire 13 that is inserted through the flexible conduit of the second feed path 39.

[0057] Fig. 8 is a perspective view of a main part of the second connection part 43. For ease of understanding, the second connection part 43 shown in Fig. 8 does not include an outer member covering the second connection part 43.

[0058] A plug 75A is fixed to the end of the flexible conduit on the second connection portion 43 side of the second feed path 39. The plug 75A has a circumferential groove 81 formed on its outer periphery, and is inserted into the connection unit 37. An engagement pin 83 that engages with the circumferential groove 81 in a direction perpendicular to the axis of the welding wire 13 is fixed to the connection unit 37. When a twist occurs in the second feed path 39, the welding robot 11 can release the twist in the second feed path 39 by rotating the plug 75A with respect to the engagement pin 83 fixed to the connection unit 37 by a bearing mechanism.

[0059] Next, a release mechanism for releasing the twist of the welding wire 13 in the first feeding path 35 will be described with reference to Fig. 9. Fig. 9 is a plan view of the first connection portion 41.

[0060] A bearing mechanism that rotates around the axis of the welding wire 13 may be provided in the first connection portion 41. The bearing mechanism is configured using a plug 75B fixed to the flexible conduit of the first feed path 35 and a coupler 77B rotatably connected to the plug 75B.

[0061] The first connection portion 41 includes a bearing mechanism, which prevents a decrease in the straightness of the welding wire 13 fed to the welding wire straightener 21, thereby facilitating straightening of the welding wire 13 by the welding wire straightener 21. Since the first connection portion 41 is located upstream of the welding wire straightener 21, the bearing mechanism may be omitted.

[0062] Fig. 10 is an enlarged plan view of the first connection portion 41. For ease of understanding, the coupler 77B is omitted from the first connection portion 41 shown in Fig. 10.

[0063] The coupler 77B is provided with an insertion hole (not shown) into which the plug 75B is inserted. A plurality of balls 79 biased radially inward are held in the inner circumferential direction on the inner circumferential surface of the insertion hole. A circumferential groove 81 into which the balls 79 enter is formed on the outer periphery of the plug 75B. The first connection portion 41 allows the balls 79 to retract radially outward by moving in a direction along the axis of the coupler 77B, allowing the plug 75B to be attached or detached.

[0064] As a result, when a twist occurs in the first feed path 35, the welding robot 11 can release the bending, twisting, etc. of the first feed path 35 by rotating the plug 75B relative to the coupler 77B fixed to the connection unit 37 by a bearing mechanism.

[0065] FIG. 11 is a perspective view of a main part showing an example of a bearing mechanism.

[0066] The bearing mechanism is not limited to the two bearing mechanisms described above, and may have other configurations. For example, the bearing mechanism shown in FIG. 11 has a plug 75C fixed to an end of a flexible conduit on the upstream side of the second feed path 39 in the feed direction of the welding wire 13. The plug 75C has a plurality of semispherical recesses 85 formed on the outer circumferential surface of the plug 75C. The recesses 85 are arranged in the circumferential direction of the plug 75C. The connection unit 37 has an insertion hole that receives the plug 75C, an inner peripheral groove provided on the inner periphery of the insertion hole, and a plurality of balls 79 held in the inner peripheral groove. Each of the plurality of balls 79 can enter a corresponding one of the recesses 85 and can be retracted radially outward.

[0067] As described above, when a twist occurs in the second feed path 39, the welding robot 11 having the bearing mechanism shown in FIG. 11 can release the bending, twisting, etc. of the welding wire 13 in the second feed path 39 by rolling the ball 79 engaged with the plug 75 along the inner circumferential groove of the connection unit 37.

[0068] Each of the above-mentioned bearing mechanisms may be applied to either the first connecting portion 41 or the second connecting portion 43. For example, the bearing mechanisms described with reference to Figs. 6 to 8 and 11 may be applied to the first connecting portion 41, or may be applied to both the first connecting portion 41 and the second connecting portion 43. Similarly, the bearing mechanisms described with reference to Figs. 9 and 10 may be applied to the second connecting portion 43, or may be applied to both the first connecting portion 41 and the second connecting portion 43.

[0069] As described above, the welding robot 11 according to the first embodiment is provided with mechanisms such as a bearing mechanism, pan bearing 53, or tilt bearing 61 in the connection unit 37, the connection portion, etc., so that it can release bending, twisting, etc. of the welding wire 13. This allows the welding robot 11 to supply the welding wire 13 from the wire supply source 33 to the torch 19 in a state in which the welding wire 13 is closer to being straight while suppressing a decrease in the straightness of the welding wire 13. Therefore, the welding robot 11 can more effectively suppress deviations in the position of the welding point (off-target) caused by bending, twisting, etc. of the welding wire 13, and can realize higher quality welding.

[0070] FIG. 12 is an enlarged view of a main portion of the torch neck 87. As shown in FIG.

[0071] Torch 19 has a bent shape in torch neck 87 to facilitate access to the welding point. It is preferable that the bent shape of torch neck 87 is formed such that the bending angle θ is smaller and the bending radius R3 (radius of curvature) is larger in order to suppress deformation of welding wire 13 protruding from the tip of torch 19 toward the welding point.

[0072] Here, materials such as mild steel or SUS (Stainless Used Steel) are generally used for the welding wire 13. Mild steel and SUS have different residual strains when bent due to the application of an external force.

[0073] In welding robot 11 according to the first embodiment, torch neck 87 has bending angle θ and bending radius R3 such that the radius of curvature Φ of welding wire 13 protruding from the tip of forced power feed tip 15 is 1200 or more.

[0074] Torch neck 87 has a bent shape along a curvature circle 89A having a bend angle θ and a bend radius R3 centered at position Ps1. Torch neck 87 causes welding wire 13 to protrude from the tip of forced-power feed tip 15 so as to describe a curvature circle 89B having a curvature radius Φ centered at position Ps2.

[0075] Hereinafter, the bending angle θ and bending radius R3 of the torch neck 87 of the welding robot 11 that results in the radius of curvature Φ of the welding wire 13 protruding from the end of the forced power feed tip 15 being 1200 or more will be described with reference to FIG.

[0076] Fig. 13 is a correlation table between the bending angle θ and the bending radius R3 of the torch neck 87 having a curvature radius Φ of 1200 or more. Note that the correlation table shown in Fig. 13 shows the correlation between the bending angle θ and the bending radius R3 when the diameter of the welding wire 13 is 1.2 mm.

[0077] The bending radius R3 is the radius of curvature of the torch neck 87 shown in Fig. 12. The bending angle θ is the angle of bending applied to the torch neck 87 shown in Fig. 12. The filled-in range in the correlation table indicates the range in which the radius of curvature Φ of the welding wire 13 protruding from the tip of the forced power feed tip 15 is 1200 or more.

[0078] 13, for example, if torch neck 87 has bending radius R3=100 mm and bending angle θ=10° to 60°, then welding wire 13 can have a curvature radius Φ=1200 or more. Also, if torch neck 87 has bending radius R3=40 mm and bending angle θ=10° to 20°, then welding wire 13 can have a curvature radius Φ=1200 or more. Note that in welding robot 11 according to embodiment 1, torch neck 87 may have bending radius R3=40 mm or less and bending angle θ=10° or less.

[0079] Next, the operation of the welding robot 11 will be described.

[0080] When the welding robot 11 starts a welding operation, it drives the welding wire feeding motor 31 to pull out the spool-wound or pack-wound welding wire 13 from the wire supply source 33 and feed it toward the tip of the torch 19. The welding wire 13 pulled out from the wire supply source 33 enters a first feeding path 35. The welding wire 13 that has entered the first feeding path 35 enters the welding wire straightener 21. The welding wire straightener 21 has two sets of units arranged perpendicular to each other. Each unit has at least three rollers that apply pressure to the pulled-in welding wire 13. The welding wire straightener 21 straightens the welding wire 13 into a substantially straight state.

[0081] The welding wire 13 straightened to a substantially straight state by the welding wire straightener 21 passes through the connection unit 37 and enters the second feed path 39. The welding wire 13 enters the torch 19 from the second feed path 39 and is fed to the forced power feed tip 15 at the tip of the torch 19. The welding wire 13, to which power is fed by the forced power feed tip 15, protrudes from the forced power feed tip 15 toward the welding point on the base material to be welded.

[0082] When the torch 19 is displaced backward (toward the wire supply source 33) due to a change in the posture of each part of the manipulator 17, the welding robot 11 applies a force to the curved flexible conduit of the second feed path 39 to increase the curvature. The second feed path 39 swings the connection unit 37 backward due to a restoring force (reaction force), and the second feed path 39 maintains a small curvature. Since the welding wire 13 is inserted through the inside of such a flexible conduit, deformation of the welding wire 13 within the second feed path 39 is suppressed. As described above, the welding robot 11 can stably feed the welding wire 13.

[0083] In order to achieve a higher straightening effect on the welding wire 13, it is desirable to attach the welding wire straightener 21 near the forced power feed tip 15. Hereinafter, a welding robot equipped with the welding wire straightener 21 above the torch 19 will be described.

[0084] (Modification of the first embodiment) The welding robot 11 according to the first embodiment has been described as an example configuration including a welding wire feed motor 31 above the torch 19 and a welding wire straightener 21 on the wire supply source 33 side. The welding robot 91 according to a modified example of the first embodiment has been described as an example configuration including a welding wire straightener 21 above the torch 19 and a welding wire feeder 93 that can achieve the same function as the welding wire feed motor 31 on the wire supply source 33 side.

[0085] In the following description, the same components as those in the welding robot 11 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0086] FIG. 14 is an external side view of a welding robot 91 according to a modification of the first embodiment.

[0087] A welding robot 91 according to a modification of the first embodiment is an example of a welding system, and includes a welding wire straightener 21 on an upper portion of a torch 19. The welding wire 13 is fed from a wire supply source 33 toward the tip of the torch 19 by a welding wire feeder 93. The welding wire feeder 93 is fixed to a back portion of the manipulator 17, and is provided between the first feed path 35 and the second feed path 39.

[0088] That is, in the welding robot 91, the welding wire 13 is drawn out from the wire supply source 33 through the first feeding path 35 by the welding wire feeder 93, enters the second feeding path 39 and is fed to the welding wire straightener 21. The welding wire 13 that has entered the welding wire straightener 21 enters the nearest torch 19 without passing through a flexible conduit, is fed with power via the forced power feed tip 15 provided at the tip of the torch 19, and then protrudes toward the welding point on the base material to be welded.

[0089] As described above, in the welding robot 91 according to the modification of the first embodiment, the welding wire straightener 21 is disposed immediately adjacent to the torch 19. The welding wire 13 straightened by the welding wire straightener 21 and thus formed is fed to the torch 19.

[0090] This allows the welding robot 91 to feed a straighter welding wire 13 from the forced power feed tip 15 toward the welding point, thereby reducing the positional deviation of the welding point. Furthermore, by reducing the positional deviation of the welding point, the welding robot 91 can improve the welding quality.

[0091] Furthermore, welding robot 91 according to the modification of embodiment 1 imparts a bend to welding wire 13 through wire supply source 33 and the feed path from wire supply source 33 to welding wire straightener 21 (i.e., first feed path 35 and second feed path 39). However, welding wire 13 is straightened by welding wire straightener 21 disposed above torch 19 before entering torch 19. Therefore, welding robot 91 according to the modification of embodiment 1 can omit various mechanisms (such as a bearing mechanism, pan bearing 53, and tilt bearing 61) for releasing the bend in welding wire 13 on the feed path.

[0092] As described above, the welding robot 11, 91 (an example of a welding system) according to embodiment 1 and the modified example of embodiment 1 includes a forced power feed tip 15 (an example of a tip) having a forced power feed mechanism at its tip that biases the welding wire 13 and feeds power to the welding wire 13, a torch 19 having the forced power feed tip 15 at its tip and feeding the welding wire 13 toward the welding point, a manipulator 17 (an example of an automatic machine) that holds the torch 19, and a welding wire straightener 21 attached to the manipulator 17 and straightening the bending tendency of the welding wire 13.

[0093] As a result, the welding robots 11 and 91 according to the first embodiment and the modified example of the first embodiment straighten the bending tendency of the welding wire 13 using the welding wire straightener 21, and protrude the welding wire 13 with the straightened bending tendency from the forced power feed tip 15 at the tip of the torch 19 toward the welding point. This makes it possible to suppress the positional deviation (off-target) of the welding point to a smaller extent even if the protruding length of the welding wire 13 becomes long. In other words, the welding robots 11 and 91 do not need to straighten the welding wire 13 using the torch 19, and therefore do not need an insulating guide that has been used in the conventional torch. Therefore, the welding robots 11 and 91 can suppress off-target welding while increasing the welding efficiency of HEAT welding using the inexpensive torch 19.

[0094] As described above, the welding wire straightener 21 in the welding robots 11 and 91 according to the first embodiment and the modified example of the first embodiment substantially straightens the welding wire 13 protruding from the forced power feed tip 15. As a result, in the welding robots 11 and 91 according to the first embodiment and the modified example of the first embodiment, the welding wire 13 that has been substantially straightened by the welding wire straightener 21 passes through the freely bendable feed path (first feed path 35 and second feed path 39) and the torch neck 87 that is bent at a predetermined bending angle θ, and can protrude from the forced power feed tip 15. Even without an insulating guide, the positional deviation (off-target) of the welding point can be further suppressed.

[0095] As described above, manipulator 17 in welding robot 11 according to embodiment 1 performs welding in a posture in which welding wire 13 is bent at an angle of less than 180° and has a bending radius of 150 mm or more in at least a part of the feeding path of welding wire 13 from wire supply source 33 (an example of a supply source) to torch 19. This allows welding robot 11 according to embodiment 1 to suppress a decrease in the straightness of welding wire 13 in the feeding path during welding.

[0096] That is, the flexible conduit (i.e., second feed path 39) follows the operation of manipulator 17, so that the bending radius (meaning the minimum radius of curvature (minimum bending radius) of the circle of curvature of the U-shaped bent portion) is maintained at 150 mm or more, and the bending angle (meaning the minimum angle (minimum bending angle) of the arc along the circle of curvature of the U-shaped bent portion) is maintained at less than 180°. Furthermore, when the flexible conduit is bent, for example, into an S shape, there are at least two U-shaped bent portions with a bending angle of 180°, and in such a case, both of the two U-shaped bent portions have a bending radius of 150 mm or more.

[0097] As a result, the minimum bending radius of the feed path of the welding robot 11 is 150 mm. That is, the welding robot 11 can suppress the occurrence of a new bending tendency in the welding wire 13 inserted through the second feed path 39 due to the displacement of the second feed path 39 caused by the movement of the manipulator 17 during welding, and suppress the deterioration of the straightness of the welding wire 13.

[0098] As described above, the welding robot 11 according to the first embodiment includes the second connection part 43 (an example of a connection part) connected to the feed path, and the connection unit 37 that fixes the second connection part 43 to the manipulator 17. The connection unit 37 has a mechanism (for example, a pan bearing 53 or a tilt bearing 61) that rotates the connection unit 37 itself. As a result, the welding robot 11 according to the first embodiment can adjust the length of the welding wire 13 in the second feed path 39 by connecting an end of a flexible conduit that constitutes the second feed path 39 to the second connection part 43, and by rotating the connection unit 37 that fixes the second connection part 43 to the manipulator 17 by the pan bearing 53 or the tilt bearing 61. Therefore, the welding robot 11 can more effectively suppress the welding wire 13 from becoming bent, twisted, or the like in the second feed path 39.

[0099] As described above, in the welding robot 11 according to the first embodiment, the second connection part 43 connected to the feeding path has a bearing mechanism (one example of a mechanism) that rotates around the axis of the welding wire 13 as the center of rotation. As a result, the welding robot 11 according to the first embodiment can release the twist of the welding wire 13 by rotating in the rotation direction S around the central axis of the flexible conduit (i.e., the axis of the welding wire 13). The twist of the welding wire 13 causes the flexible conduit and the welding wire 13 to curl in a spiral shape, thereby reducing the bending radius of the welding wire 13. By releasing the twist of the welding wire 13, the bending radius of the flexible conduit and the welding wire 13 can be increased. Therefore, the welding robot 11 can maintain the bending radius of the flexible conduit and the welding wire 13 at 150 mm or more throughout the second feeding path 39 by rotating the second connection part 43.

[0100] As described above, in the welding robot 91 according to the modification of the first embodiment, the welding wire straightener 21 is provided above the torch 19. As a result, the welding robot 91 according to the modification of the first embodiment straightens the bending tendency of the welding wire 13 immediately before the torch 19. The welding wire 13 that has been straightened to be approximately straight is directly supplied to the torch 19. Therefore, the welding wire 13 supplied to the forced power feed tip 15 is bent only at the torch neck 87. Since the welding robot 91 straightens the welding wire 13 immediately adjacent to the torch 19 by the welding wire straightener 21, deterioration in the straightness of the welding wire 13 can be further suppressed.

[0101] As described above, torch 19 in welding robot 11 according to embodiment 1 has welding wire feeding motor 31. Welding wire straightener 21 is provided near wire supply source 33 (an example of a supply source) of welding wire 13. This allows welding robot 11 according to embodiment 1 to stroke welding wire 13 between torch 19 and second feeding path 39 by forward and reverse feeding operations.

[0102] The arc welding control method in which the stroke control is performed as described above can reduce the amount of welding wire fed during the short circuit period by feeding the welding wire in reverse during the short circuit period in which a short circuit occurs, and can release the short circuit state and generate an arc in a shorter time than when the welding wire is not fed in reverse. Furthermore, this arc welding control method can stably burn up the welding wire and form droplets by changing the welding wire feed from reverse to forward after the short circuit is released and increasing the welding current to a predetermined peak current. As a result, the welding robot 11 employing the arc welding control method can more effectively prevent the welding wire 13 from being ripped off due to a long-term short circuit, the short circuit cycle from being disturbed, and the like, and can achieve more stable welding.

[0103] Furthermore, when the welding wire is fed in reverse, the welding robot 11 must ensure an excess length on the upstream side of the welding wire feed direction so that the welding wire 13 can be deformed in the axial direction by an amount corresponding to the amount of the welding wire 13 fed in reverse. In the welding robot 11, a welding wire feed motor 31 provided in the torch 19 is connected to a welding wire straightener 21 mounted on the rear part (wire supply source 33 side) of the manipulator 17 by a flexible conduit. The rear end of the flexible conduit is connected to the welding wire straightener 21 via a connection unit 37. As a result, the second feeding path 39, which connects the welding wire feed motor 31 and the connection unit 37, can accommodate (allow) the excess length of the welding wire 13 required for the reverse feed.

[0104] As described above, the torch 19 in the welding robots 11, 91 according to the first embodiment and the modified example of the first embodiment has a torch neck 87. The bending angle of the torch neck 87 is smaller than the bending angle of the welding wire 13 in a case where it is assumed that the torch neck 87 is not bent (the bending angle of the torch neck 87 is 0°). In other words, the bending angle of the torch neck 87 is smaller than the angle at which the curvature of the welding wire 13 passing through the torch neck 87 is increased after being straightened by the welding wire straightener 21. Note that the "angle at which the curvature of the passing welding wire 13 is increased" here refers to the angle at which the bending of the welding wire 13 straightened by the welding wire straightener 21 is increased (i.e., the bending angle is increased). As a result, in the welding robots 11, 91 according to embodiment 1 and the modified example of embodiment 1, the bending angle of the torch neck 87 is greater than the angle that increases the curvature of the passing welding wire 13, so that the welding wire 13 can be protruded from the tip of the forced power feed tip 15 without bending the welding wire 13 any more significantly and while remaining in a substantially straight state.

[0105] Although various embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. In addition, the components in the various embodiments described above may be arbitrarily combined within the scope of the invention. [Industrial Applicability]

[0106] INDUSTRIAL APPLICABILITY The present disclosure is useful as providing a welding system that can more effectively suppress misalignment of a welding point even if the extension length of a welding wire is increased. [Explanation of symbols]

[0107] 11,91 Welding robot 13 Welding wire 15 Forced Power Chip 17 Manipulator 19. Torch 21 Welding wire straightening machine 23. Robot 31 Welding wire feed motor 35 First supply route 37 Connection Unit 39 Second Supply Route 41 First connection part 43 Second connection part 45 Third Connection 53 Pan Bearing 61 Tilt Bearing 63 Unit body 65 Roller bearing 75 Plug 87 Torch Neck

Claims

1. a tip having a forced power supply mechanism at a tip end for biasing the welding wire and supplying power to the welding wire; a torch having the tip at a front end thereof and supplying the welding wire toward a welding point; An automated machine for holding the torch; a welding wire straightening machine attached to the automatic machine and configured to straighten the welding wire, the welding wire straightener straightens the welding wire protruding from the tip, the automatic machine performs welding in a position in which the welding wire has a bend angle of less than 180° and a bend radius of 150 mm or more in at least a part of a feed path of the welding wire from a supply source of the welding wire to the torch; A connection portion connected to the supply path; a connection unit that fixes the connection portion to the automatic machine, The connection unit has a mechanism for rotating the connection unit itself. Welding system.

2. The connection portion connected to the feed path has a mechanism that rotates around an axis of the welding wire. The welding system of claim 1 .

3. The welding wire straightener is provided on the upper part of the torch. The welding system of claim 1 .

4. The torch has a motor for feeding a welding wire, The welding wire straightener is provided near a source of the welding wire. The welding system according to claim 1 or 2.

5. The torch has a torch neck; The bend angle of the torch neck is smaller than the bend angle of the welding wire assuming that the torch neck is not bent. The welding system of claim 3 .

6. The torch has a torch neck; The bend angle of the torch neck is smaller than the bend angle of the welding wire assuming that the torch neck is not bent. The welding system of claim 4 .

7. The torch has a torch neck; The bend radius of the torch neck is greater than the bend radius of the welding wire assuming that the torch neck is not bent. The welding system of claim 3 .

8. The torch has a torch neck; The bend radius of the torch neck is greater than the bend radius of the welding wire assuming that the torch neck is not bent. The welding system of claim 4 .

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