JP2011031257A - Apparatus for supplying filler wire in laser welding and method for supplying the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for supplying filler wire capable of suitably fusing filler wire without affecting a laser welding state, and also to provide a method for supplying the same. <P>SOLUTION: The apparatus 3 for supplying the filler wire has a filler wire heating device 6 for heating the filler wire X. The heating device 6 includes: a roller 51A contacting with a part in the vicinity of the end of the filler wire X; a clamp 5 contacting with metal plates W1, W2; an energizing device 30 for causing energization through the filler wire X and the metal plates W1, W2 between the roller 51A and the clamp 5; and a moving mechanism 60 for moving the roller 51A while allowing it to contact with the filler wire X in such a way as to change the distance between the roller 51A and the end of the filler wire X. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a filler wire supply apparatus and a supply method for supplying a filler wire to a welded portion by laser light when laser welding a plurality of metal members, and belongs to the technical field of laser welding.

  In recent years, laser welding is being used as a welding method for a plurality of metal members. In this laser welding, a laser beam irradiated portion of a plurality of metal members is moved by moving the laser beam with respect to the metal member along a predetermined welding path while irradiating the laser beam toward the surface of the metal member. It is melted to form a linear weld bead.

  Here, there may be a gap between the metal members. In this case, the metal members may not be joined together due to lack of molten metal. As a method for solving this problem, a method is known in which a filler wire is supplied so as to follow the movement of the irradiated portion of the laser beam, the wire is melted, and the molten metal is increased.

  In order to improve the meltability of the filler wire during welding, the filler wire is heated. Specifically, as disclosed in Patent Literature 1, Joule heat is generated and heated by energizing a portion near the end of the filler wire during welding. More specifically, at the time of welding, the end of the filler wire comes into contact with the welded portion of the metal member. Therefore, a plus electrode is brought into contact with a portion near the end of the filler wire, a minus electrode is brought into contact with the metal member, and a voltage is applied between both electrodes in this state. Thereby, the end side part in the filler wire is energized through the metal member. In addition, the welding apparatus which concerns on this literature 1 is an apparatus which performs not TIG welding but laser welding.

JP 2002-103040 A

  By the way, when laser welding a metal member while supplying a filler wire, the welding state changes due to changes in various conditions such as the ambient temperature and the temperature of the metal member. For example, the amount of heat acting on the end of the filler wire is insufficient, and the filler wire may not be melted properly, and as a result, the filler wire may remain unmelted at the site to be welded.

  As a countermeasure to this problem, it is conceivable to control the amount of heat applied to the welded part. Specifically, for example, the laser output is changed or the welding speed (laser beam moving speed) is changed. However, the change of the laser output has a great influence on the depth of the fusion hole formed in the metal material. Also, changing the welding speed affects the production speed.

  Then, this invention makes it a subject to provide the filler wire supply apparatus and supply method which can melt | fuse a filler wire favorably, without having a bad influence on a laser welding state.

  In order to solve the above-described problems, the present invention is configured as follows.

  First, the invention according to claim 1 of the present application provides a filler so that an end portion of a plurality of metal members follow a welded portion by a laser beam that moves relatively along a predetermined welding path in a contact state. A filler wire supply device for supplying a wire at a predetermined speed, comprising heating means for heating the filler wire, wherein the heating means includes a first electrode that contacts a portion near the end of the filler wire, and the metal A distance between the second electrode that contacts the member, an energizing means for energizing the first electrode and the second electrode via a filler wire and a metal member, and an end of the first electrode and the filler wire And an electrode moving means for moving the first electrode while maintaining contact with the filler wire so as to change.

  According to a second aspect of the present invention, there is provided the filler wire supply device in laser welding according to the first aspect, wherein an imaging unit that images the welded portion and an image captured by the imaging unit are analyzed. Determining means for determining the connection state between the metal members by analyzing the state of penetration of the filler wire into the welded part, and the electrode moving means is based on the determination result of the determining means, The first electrode is moved.

  Further, the invention according to claim 3 is the filler wire supply device in laser welding according to claim 2, wherein the determination means is greater than or equal to a predetermined value of the filler wire based on an image captured by the previous imaging means. When the bending is detected, it is determined that the connection state between the metal members is not good, and when the determination unit determines that the connection state is not good, the first electrode is connected to the filler wire. It is made to move in the direction away from the edge part of this.

  According to a fourth aspect of the present invention, in the filler wire supply apparatus for laser welding according to any one of the first to third aspects, the first electrode supports the filler wire so as to be movable. It is characterized by being comprised by the roller to do.

  The invention according to claim 5 is the filler wire supply apparatus in laser welding according to any one of claims 1 to 4, wherein the filler wire supply means is configured to supply the filler wire to the laser. It is characterized in that it is supplied at a position rearward of the laser light irradiated portion so that the end portion is in contact with a molten pool formed at a portion to be welded by light and storing molten metal.

  In the invention according to claim 6, the filler wire is moved at a predetermined speed so that the end portion follows the welded portion by the laser beam that moves relative to the plurality of metal members along a predetermined welding path. A filler wire supply method for supplying, comprising: a heating step of heating the filler wire by energizing the filler wire, wherein the heating step is performed between the first electrode and the metal member in contact with the vicinity of the end portion of the filler wire. Between the first electrode and the end of the filler wire when a predetermined state is established while energizing through the filler wire and the metal member between the second electrode and at least one of them The first electrode is moved while maintaining contact with the filler wire so that the distance changes.

  Next, the effect of the present invention will be described.

  First, according to the first aspect of the present invention, at the time of laser welding, a predetermined speed is obtained so as to follow a welded portion by a laser beam that moves relative to a plurality of metal members along a predetermined welding path. The filler wire is supplied. At that time, the filler wire is energized and heated by the heating means.

  Here, heat generation of the filler wire in a state where the filler wire is supplied at a predetermined speed will be considered. For example, when a portion having a minute length in the longitudinal direction from the upstream side of the first electrode (for example, a portion corresponding to a length of 1 mm in the longitudinal direction, hereinafter referred to as a predetermined portion) is sent at a predetermined speed, A current flows through the predetermined portion from the time when the first electrode position is reached until the position to be welded is reached. At this time, due to the resistance, the predetermined portion generates heat from the time when it reaches the position of the first electrode until it reaches the welded portion, and the temperature gradually rises, and the temperature increases toward the end side.

  In that case, in this invention, it is comprised so that the distance between the said 1st electrode and the edge part of a filler wire can be changed. That is, the electrode moving means is configured to move the first electrode while maintaining contact with the filler wire so that the length of the portion where the current flows in the filler wire (energized portion) can be changed. Yes.

  According to this, the time from when the predetermined portion of the filler wire reaches the first electrode position until it reaches the welded portion, that is, the energization time for the predetermined portion changes, and the temperature rise amount of the predetermined portion also changes. It will be. For example, when the first electrode is moved in a direction away from the end (tip) of the filler wire, the energization time for the predetermined portion becomes longer and the amount of temperature rise increases. As a result, the tip temperature of the filler wire (temperature immediately before contacting the molten pool) is further increased. On the other hand, when the first electrode is moved in a direction approaching the end of the filler wire, the length of the energized portion is shortened, the energization time for the predetermined portion is shortened, and the temperature rise is reduced. As a result, an increase in the tip temperature of the filler wire (temperature immediately before contacting the molten pool) is suppressed.

  Note that, when the length of the energized portion of the filler wire is changed, the resistance of the entire heating unit changes, so that the current flowing through the predetermined portion changes when the output voltage of the heating unit is constant. However, the resistance value of the filler wire portion is usually the total resistance of the circuit for energizing the filler wire (for example, the resistance of the cable for connecting to the filler wire, the resistance of the metal material to be welded, the resistance of the molten pool) The sum of the resistance of the power supply device, the contact resistance between the filler wire and the molten pool, etc.) is sufficiently smaller. Therefore, even if the length of the energized portion is changed, a substantially constant current flows through the filler wire. As a result, the heat generation per unit time in the predetermined portion of the filler wire is substantially constant regardless of the length of the energized portion. That is, the tip temperature of the filler wire can be changed according to the length of the energized portion.

  Next, according to the second aspect of the present invention, the connection state between the metal members is determined by analyzing the image captured by the imaging means and analyzing the state of penetration of the filler wire into the welded part. Is done. And based on the determination result of the determination means, the first electrode is moved by the electrode moving means. Thereby, welding according to an infiltration state is attained during laser welding.

  According to the third aspect of the present invention, it is determined that the connection state between the metal members is not good when a predetermined bending or more of the filler wire is detected in the welded portion. When the filler wire is bent more than a predetermined amount, it is considered that the end portion thereof is not sufficiently melted and hits an unmelted portion of the metal material. That is, it is considered that the connection state between the metal members is not good due to a lack of heat supplied to the welded part. Therefore, in such a case, it is determined that the connection state between the metal members is not good. In such a case, the first electrode is moved in a direction away from the end of the filler wire by the electrode moving means. Thereby, the length of the electricity supply part in a filler wire becomes long, and the temperature of an edge part side can be made higher than the present condition. As a result, it will change in the direction where the malfunction of the connection of the metal member by lack of calorie | elimination is eliminated.

  According to the invention described in claim 4, since the first electrode is constituted by a roller that supports the filler wire so as to be movable, a current is supplied to the filler wire while supporting the movement of the filler wire. It can flow. That is, the electrode and the support can be shared by one member, and the parts constituting the filler wire supply device can be reduced.

  According to a fifth aspect of the present invention, the laser beam is formed so that the filler wire is in contact with a molten pool formed at the irradiated portion of the laser beam and storing molten metal. In the case where the filler wire is heated so as to be melted with the heat of the molten pool when it is supplied from a position behind the light irradiated portion and comes into contact with the molten pool, the actions and effects of the above claims are can get. That is, when the filler wire is melted not by laser light but by the heat of the molten pool, the filler wire may not be melted unless the filler wire is sufficiently heated. However, this problem can be solved satisfactorily by applying the inventions described in the above claims.

  Moreover, according to the method invention of Claim 6, the effect | action and effect demonstrated in the apparatus invention of Claim 1 will be acquired.

1 is an external perspective view of a laser welding apparatus according to a first embodiment of the present invention. It is a cross-sectional photograph of the welded part of two metal plates. It is a perspective view which shows the laser beam irradiation site | part of a metal plate in laser welding, and the state of the vicinity. (A): It is a top view which shows the laser beam irradiation site | part of a metal plate in laser welding, and the state of the vicinity. (B): It is AA sectional drawing of the figure (a). (A): BB sectional view of FIG. 4 (b), (b): CC sectional view of FIG. 4 (b), (c): DD sectional view of FIG. 4 (b), (d) ): EE sectional view of FIG. 4 (b), (e): FF sectional view of FIG. 4 (b), (f): GG sectional view of FIG. 4 (b). It is explanatory drawing by the same cross section as FIG.4 (b) for demonstrating an example when a malfunction arises in fusion | melting of a filler wire at the time of a welding start. It is sectional drawing of the front-back direction of a wire heating head. FIG. 9 is a lateral sectional view (HH sectional view of FIG. 7) of the wire heating head. It is a control block diagram of a laser welding apparatus. It is explanatory drawing of the effect | action at the time of welding (the 1). It is explanatory drawing of the effect | action at the time of welding (the 2). It is a characteristic figure of the amount of temperature rises and tip temperature when changing the length of the energization part in a filler wire. It is explanatory drawing of resistance of the whole filler wire heating apparatus. FIG. 11 is a diagram corresponding to FIG. 10 for describing another example of the present embodiment (part 1); FIG. 11 is a diagram corresponding to FIG. 10 for describing another example of the present embodiment (part 2);

  Hereinafter, a laser welding method and a laser welding apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is an external perspective view of a laser welding apparatus 1 according to the present embodiment. The laser welding apparatus 1 includes a laser head 2 that generates a laser beam LB (laser beam), a filler wire supply device 3 that supplies a filler wire X to the rear of a laser beam irradiated position L from the laser head 2, and It has a moving device 4 that supports the laser head 2 and the filler wire supply device 3 and moves it relative to the workpiece W. In addition, as the workpiece | work W, the metal plates W1 and W2 of a cross-sectional hat shape which swelled in the opposite direction mutually and the flanges were piled up and down are shown as an example. Although the flanges of the metal plates W1 and W2 are held by a plurality of clamps 5 ... 5, a gap Z is generated between the opposing surfaces for the accuracy of the metal plates W1 and W2.

  The laser head 2 is configured using a high output laser such as a YAG laser or a carbon dioxide gas laser, and the laser output is variable. The focal position of the laser beam is variable, but is set on the upper surface of the upper metal plate W1 in the present embodiment.

  The filler wire supply device 3 is driven by a wire roll 12 around which a filler wire X is wound, a motor (not shown), a feeding roller 13 that feeds the filler wire X from the wire roll 12, and a target of laser light LB. A wire supply nozzle 11 disposed in the vicinity of the irradiation site L, a filler wire heating head 40 provided at the rear of the nozzle 11 for heating the filler wire X, and between the feeding roller 13 and the filler wire heating head 40 And a tube 14 for guiding the filler wire X fed out by the feeding roller 13 to the heating head 40. The motor is composed of a servo motor capable of controlling the rotation speed, and this makes it possible to adjust the supply amount of the wire X to the welded portion (corresponding to a molten pool WY described later in the present embodiment). ing.

  The moving device 4 is disposed on a support member 21 to which the laser head 2 and the filler wire supply device 3 are attached, a base member 22 attached to the lower end of the support member 21, a factory floor, etc. A rail member 23 that slidably supports the base member 22 and a moving mechanism (not shown) that moves the base member 22 along the rail member 23 are provided. The moving mechanism for moving in this way can be variously configured by known ones and will not be described. However, the drive source is composed of a servo motor (not shown) capable of controlling the rotation speed, and thereby the laser head 11 and The moving speed of the filler wire supply device 3 with respect to the workpiece W can be adjusted.

  Moreover, the laser welding apparatus 1 has a filler wire heating device 6 that heats the filler wire X to a predetermined temperature. The filler wire heating device 6 heats the wire X by Joule heat generated in the wire X by energizing the end of the filler wire X. The heating power supply device 31 and the heating head 40 described above are used. A heating head connection cable 32 that connects the heating power supply device 31 and the heating head 40, and a clamp connection cable 33 that connects the heating power supply device 31 and one of the plurality of clamps 5. The current flowing from the power supply device 31 returns to the heating power supply device 31 via the nozzle connection cable 32, the heating head 40, the filler wire X, the metal plates W <b> 1 and W <b> 2, the clamp 5, and the clamp connection cable 33. Here, the predetermined temperature is set to a temperature that melts with the heat of the molten pool WY (molten metal Wy) when the end of the filler wire X comes into contact with the molten pool WY described later. The current value for heating the filler wire X to a predetermined temperature may be derived by conducting an experiment or the like.

  FIG. 2 is a cross-sectional photograph (one example) in the width direction of a workpiece having good welding strength when two metal plates W1 and W2 having a gap Z are welded while supplying filler wire X. . As can be seen from this photograph, the two metal plates W1 and W2 are connected via a bead WB formed by solidifying the molten metal Wy. Further, on the left and right sides of the bead WB in the width direction, there are heat-affected portions WC1 and WC2 (parts between whitish discoloration on the left and right of the bead WB) in which the metal structure changes in the upper and lower metal plates W1 and W2, respectively. Existing. FIG. 3 is an example, and the upper and lower metal plates W1 and W2 each have a thickness of 1.6 mm and a gap Z of 1.3 mm.

  Here, in such a structure, the upper metal plate W1 melted by the laser beam LB and the molten metal of the filler wire X hang down to the lower metal plate W2 to connect the upper and lower metal plates W1, W2, This molten metal is formed by cooling and solidifying to form a bead WB. The heat affected portions WC1 and WC2 are formed by transferring the heat of the molten metal in the width direction of the metal plates W1 and W2.

  By the way, according to the knowledge of the inventor of the present application, when the filler wire is configured to be melted with laser light, the energy of the laser is consumed to melt the filler wire, for example, the melting of the upper metal plate becomes insufficient, As a result, the molten metal of the filler wire cannot also hang downward, and the upper and lower metal plates may not be connected well by the molten metal. Therefore, in the present embodiment, the filler wire is not melted by laser light, but is melted by the following method.

  First, the outline of the welding method will be described with reference to FIG. 3. The upper metal plate W1 of the two flat plate-like metal plates W1 and W2 in which a gap Z is generated between the surfaces facing each other in a state where they are stacked one above the other. While irradiating the laser beam LB toward the surface, the laser beam LB is moved relative to the two metal W1 and W2 plates along the welding path R, thereby the laser of the upper metal plate W1. The molten portion WK is formed by melting the irradiated portion L and penetrating vertically, and a molten pool WY in which these molten metals are stored in the previously formed molten hole portion is formed behind the welding path R. Let Then, the filler wire X heated so as to be melted by the heat of the molten pool WY has an end portion in the vicinity of the rear of the molten hole WK in the molten pool WY (the specific position of the portion will be described later). Is supplied from the rear of the molten pool WY so as to be in contact with the molten metal, thereby melting the end of the filler wire X and additionally supplying molten metal to the molten pool WY.

  4 and 5, first, in the vicinity of the front of the center LBc of the laser beam LB in the welding path R, as shown in FIGS. 4 (a), 4 (b), and 5 (a), The metal in the vicinity of the laser beam center LBc in the upper metal plate W1 is melted to generate a molten metal Wy. Further, around the molten metal Wy, there is a heat affected zone WC1 in which the metal structure is changed by the heat transmitted from the molten metal Wy. WK is a molten hole (keyhole) formed by pressing the molten metal Wy to the surroundings by the pressure of the metal by the laser beam LB, and the front portion is shown in this figure.

  As shown in FIGS. 4B and 5B, at the position of the laser beam center LBc in the welding path R, the fusion hole WK passes through the upper metal plate W1 and reaches the lower metal plate W2. ing. Also in the lower metal plate W2, the metal in the vicinity of the laser beam center LBc is melted, and the molten metal Wy is generated. The molten metal Wy of the upper metal plate W1 starts to hang down to the lower metal plate W2 side due to gravity. A heat affected zone WC2 is generated around the molten metal Wy of the lower metal plate W2.

  As shown in FIGS. 4B and 5C, in the vicinity of the rear of the laser beam center LBc in the welding path R, the molten metal Wy of the upper metal plate W1 hangs further downward due to gravity. Since the metal Wy is agglomerated by surface tension, the upper metal plate W1 and the lower metal plate W2 are not connected.

  As shown in FIGS. 4B and 5D, the molten metal Wy is stored in the previously formed molten hole at a position behind the laser beam center LBc in the welding path R. As a result, a molten pool WY is formed.

  Also, as shown in FIGS. 4B and 5D, in the present embodiment, the filler wire X heated to melt with the heat of the molten pool WY as described above is melted. From the rear of the pond WY, the end thereof is supplied so as to come into contact with the vicinity of the rear of the molten hole WK in the molten pool WY, and the end of the wire X is melted to generate molten metal Wy ′. Then, the newly generated molten metal Wy ′ is supplied into the molten pool WY, whereby the molten metal Wy in the molten pool WY that originally existed is pushed downward, and the molten metal Wy The downward drooping over the gap Z is promoted, and the upper metal plate W1 and the lower metal plate W2 are connected by the molten metal Wy, Wy ′. Then, as shown in FIGS. 4B and 5E, the molten metal Wy in the molten pool WY starts to solidify from below at a position further rearward than the laser beam center LBc in the welding path R. As shown in FIG. 5 (f), further, the molten metal in the molten pool WY is all solidified from the top to the bottom, and a welded portion having a cross section as shown in FIG. 2 is formed.

  Here, the supply conditions of the filler wire X will be described in detail. As shown in FIGS. 3, 4A, and 4B, the filler wire X is indicated by an arrow β (described in FIG. 4B). As shown, the end side is supplied along the welding path R so as to be in contact with the molten pool WY while being inclined forward and downward. More specifically, the front end position of the portion of the filler wire X that intersects the upper surface of the upper metal plate W1 is supplied at a distance Dx behind the welding path R from the laser beam center LBc. This distance Dx is (1) the end side of the filler wire X is not irradiated with the laser beam LB at the upper surface position of the upper metal plate W1, and (2) the rear end position of the molten hole WK is slightly changed during welding. Even in this case, the end of the filler wire X comes into contact with the molten pool WY, and (3) the distance satisfying the three conditions is set as close as possible from the laser beam center LBc. Note that this position is a position that defines a rear vicinity portion of the molten hole WK in the molten pool WY. In the present embodiment, the distance Dx is set to a distance that is twice the beam diameter of the laser beam LB, for example.

  According to the present embodiment as described above, the filler wire X is heated so as to be melted by the heat of the molten pool WY, and the end of the filler wire X from the rear side of the laser light irradiated portion L enters the molten pool WY. By being supplied so as to be in contact with the molten pool WY, the molten metal is melted by contact with the molten pool WY. Therefore, the energy of the laser beam LB is not consumed for melting the filler wire X, but exclusively used for melting the metal plate, and the formation of the melted hole WK of the upper metal plate W1 is stabilized. Become. That is, the structure for allowing the molten metal Wy (Wy ′) of the upper metal plate W1 and the filler wire X to hang down to the lower metal plate W2 side is stably formed. Moreover, the molten metal Wy ′ of the filler wire X generated by the contact with the molten pool WY pushes the molten metal Wy originally present in the molten pool WY downward, so that the molten pool WY is melted. The downward drooping over the gap Z of the metal Wy is promoted, so that the upper and lower metal plates W1, W2 are stably and well connected. The phenomenon of promotion of the downward droop of the molten metal Wy can be understood as the molten metal Wy being injected into the gap Z and moving so as to satisfy the same as a caulking material.

  Further, in the present embodiment, since the filler wire X is supplied so that the end portion is in contact with the rear vicinity portion of the molten hole WK in the molten pool WY, the filler wire X is particularly high in the molten pool WY. Will come into contact with the molten metal Wy. Therefore, the end portion of the wire X is melted well.

  Here, when the distance Dx is defined as described above, when the rear end of the molten hole portion WK largely recedes, the end portion of the filler wire X does not contact the molten pool WY, and the heat with the molten pool WY However, in this embodiment, the filler wire X contacts the molten pool WY in a state where the end side is inclined along the welding path R and forwardly downward. When the end of the wire X is not melted in the molten pool WY, the end reaches the irradiated portion L of the laser beam LB and is melted by the irradiation of the laser beam LB. Become. That is, even if the end portion of the filler wire X is not melted in the molten pool WY, the filler wire X is prevented from being melted. As shown in FIG. 4B, the laser beam can be obtained by setting the intersection position of the laser beam center LBc and the center line Xc of the filler wire X to be lower than the upper metal plate W1. With LB, it is possible to melt the filler wire X while favorably melting the upper metal plate W1.

  By the way, according to the knowledge of the inventor of the present application, as described in the column of problems to be solved, when laser welding a metal member while supplying the filler wire X, various temperatures such as the ambient temperature and the temperature of the metal member can be used. The welding state changes due to changes in the conditions. For example, there is a case where the amount of heat acting on the end of the filler wire is insufficient and the filler wire X is not properly melted, and as a result, the filler wire X remains unmelted at the welded portion.

  Therefore, in the filler wire supply device 3 of the present embodiment, when the laser welding is performed while supplying the filler wire X to the welded portions of the plurality of metal members, the filler wire X is melted well from the start of welding, Thus, the laser welding state can be stabilized.

  More specifically, as shown in FIGS. 7 and 8, in the filler wire supply device 3 according to the present embodiment, the wire heating head 40 of the filler wire heating device 6 includes a box-shaped housing 41 and an inside of the housing 41. And a pair of upper and lower rollers 51A and 51B that are in contact with the vicinity of the end of the filler wire X, and a moving mechanism 60 that moves the rollers 51A and 51B along the longitudinal direction of the filler wire X. .

  The rollers 51A, 51B are laterally supported by a pair of support members 52, 52 supported by the moving mechanism 60 in the casing 41 so as to be movable in the longitudinal direction of the filler wire via support shafts 53A, 53B. It is rotatably supported. Between the upper portions of the support members 52 and 52, an electrode 55 is attached via an insulating material 54 above the first rollers 51A and 51B, and the electrode 55 is in contact with the upper roller 51A. The heating head connection cable 32 is connected to the electrode 55. The part in the housing | casing 41 in the 1st cable 32 has sufficient length so that a movement of support members 52, 52, etc. may not be interfered, and the measure for not hanging down below is given. . The electrode 55 is made of, for example, a carbon material.

  The upper roller 51A is formed of a metal material, and the lower roller 51B is formed of ceramics. The upper roller 51A is fixed to the support shaft 53A via an insulating material 56.

  The upper support shaft 53A is configured to be rotatable. More specifically, a gear 57 is fixed to one end of the upper support shaft 53A, and a motor 59 having a gear 58 meshing with the gear 57 at one end of the drive shaft 59a is attached to one support member 52. It has been. The rotation of the motor 59 is controlled by a control unit 100 described later.

  The support shaft 53B of the lower roller 51B is supported so as to be movable up and down within a predetermined range with respect to the support member 52, and is urged toward the upper roller 51A via an urging means (not shown). As a result, the filler wire X is sandwiched from above and below by the upper roller 51A and the lower roller 51B.

  The moving mechanism 60 extends back and forth at positions above and below the support members 52 and 52 on the inner surfaces of the upper and lower walls of the housing 41, and supports the support members 52 and 52 so as to be slidable in the front-rear direction. Rails 61, 61, 62 and 62 are provided. Racks 63, 63, 64, 64 extending in the front-rear direction are provided on the left and right sides of the rails 61, 61, 62, 62 on the inner surfaces of the upper wall and the lower wall of the housing 41. A biaxial motor 65 is fixed to the lower part of one support member 52, and its drive shaft 65a extends to the left and right through the support members 52, 52 and engages with the lower racks 64, 64 at both ends. Gears 66 and 66 are attached. Further, on the upper side of the support members 52, 52, a rotation shaft 67 that extends through the members 52, 52 to the left and right and is rotatably supported by the members 52, 52 is provided. Gears 68, 68 that mesh with the upper racks 63, 63 are attached to both ends of the rotating shaft 67. Gears 69 and 70 are attached to one end portions of the rotary shaft 67 and the drive shaft 65 a of the motor 65, respectively, and a belt 71 is wound around the gears 69 and 70. The upper rack 61 and gears 68 and 69 and the lower rack 64 and gears 66 and 70 have the same structure. According to such a configuration, when the motor 65 is operated, the upper and lower gears 68, 68, 69, 69 rotate on the racks 63, 63, 64, 64 at the same speed. The support members 62, 62 are supported by the rails 61, 61, 62, 62 and move in the longitudinal direction of the filler wire X while maintaining the same posture. And the contact position with respect to the filler wire X of the upper side roller 51A supported by the supporting members 62 and 62 changes, As a result, the energization length with respect to the filler wire X will change.

  As shown in FIG. 9, the laser welding apparatus 1 according to the present embodiment is fixed to a control unit 100 that performs welding control, and a support member 21 of the moving device 4, and a portion to be welded of the workpiece W and its vicinity. And an imaging device 110 that captures images from above.

  The imaging device 110 is constituted by, for example, a CCD camera that can acquire an image (capable of acquiring a moving image) at predetermined intervals, and the acquired image is output to the control unit 100 each time. The support member 21 of the moving device 4 is provided with a lamp 9 that illuminates the laser light irradiated portion L and the vicinity thereof on the upper metal plate W1. The lamp 9 is disposed on the opposite side of the imaging device 110 across the welding path R, and illuminates the laser light irradiated portion L and the vicinity thereof on the metal plate W1 obliquely from above. As the lamp 9, for example, a xenon lamp can be used.

  The control unit 100 outputs a rotation speed control signal to the motor 24 of the moving device 4 so that the laser head 2 (laser light) moves at a predetermined speed with respect to both metal plates W1 and W2.

  Further, the control unit 100 outputs a rotation speed control signal so that the filler wire X is supplied to the motor 15 of the filler wire supply device 10 at a predetermined supply speed.

  Further, the control unit 100 supplies the filler wire X to the roller driving motor 59 for the first rollers 51A and 51B of the wire heating head 40 at the same speed as that supplied by the wire supply motor 15 during welding. Thus, a rotation speed control signal is output.

  Further, the control unit 100 outputs a welding start signal to the filler wire heating power supply device 31 at the start of welding.

  The control unit 100 analyzes the image every time an image is input from the imaging device 110 after starting welding, and drives the roller moving motor 65 based on the analysis result. More specifically, as a result of analyzing the image, as shown in FIG. 6, when the bending of the filler wire X or the displacement of the nozzle 11 is detected, the rollers 51 </ b> A and 51 </ b> B have end portions (tips (hereinafter, appropriately, for convenience of explanation). The term “tip” is used in place of the term “end”.) The roller moving motor 65 is driven so as to move away from the end. Then, as a result of sequentially analyzing the subsequent images, when the bending of the filler wire X or the displacement of the nozzle 11 is not detected, the roller moving motor 65 is driven so as to return the rollers 51A and 51B to the initial positions.

  Next, the operation of the filler wire supply device of the present embodiment will be described.

  First, when a welding start instruction is input to the control unit 100 via, for example, a welding start operation switch or the like, the control unit 100 includes the laser head 2, the moving device motor 24, the filler wire supply device motor 15, the roller. The driving motor 59, the roller moving motor 65, and the filler wire heating power supply device 31 are simultaneously operated under predetermined conditions. The predetermined condition is set in advance for each apparatus or is set before starting welding.

  When the supply of the filler wire X starts and the end of the filler wire X comes into contact with the molten pool WY (welded part) of the metal plate W1 as shown in FIG. Connection cable 32, electrode 55, upper roller 51A (corresponding to the first electrode in the claims), filler wire X, metal plates W1, W2, clamp 5 (corresponding to the second electrode in the claims) A current route that returns to the negative terminal via the clamp connection cable 33 is formed (that is, energized). Therefore, Joule heat is generated in a portion closer to the end portion than the portion in contact with the upper roller 51A in the filler wire X, and the portion is heated. Therefore, melting of the filler wire X when supplied to the molten pool WY is promoted.

  On the other hand, when laser welding is performed while supplying the filler wire X in this way, the control unit 100 detects that the welding state is not good based on the analysis result of the image input from the imaging device 110. Is processed as follows.

  For example, as a result of analyzing the image, when the bending of the end side of the filler wire X or the displacement of the nozzle 11 is detected as shown in FIG. 11, the end side of the filler wire X is not sufficiently melted, As shown in FIG. 6, it is considered that the metal plates W1 and W2 are in contact with the unmelted portions. That is, it is considered that the connection state between the upper and lower metal plates W1 and W2 is not good due to the lack of heat supplied to the welded part.

  In this case, the roller moving motor 65 is driven so that the rollers 51A and 51B move in the direction away from the end (tip) as indicated by phantom lines. For example, as shown in FIG. 11, it is moved ΔL in the direction away from the tip. By so doing, the length of the portion of the filler wire X through which the current flows increases from L1 to L2 (L1 + ΔL). Therefore, as will be described later, the amount of temperature rise at the end of the filler wire X increases. As a result, the problem of the connection between the metal plates W1 and W2 due to the lack of heat is eliminated.

  Here, heat generation of the filler wire X in a state where the filler wire X is supplied at a predetermined speed is as follows. For example, an arbitrary portion (hereinafter referred to as a predetermined portion xa (not indicated in the drawing)) having a minute length in the longitudinal direction from the upstream side of the roller 51A (first electrode) has been sent at a predetermined speed. If this is the case, a current flows through the predetermined portion xa for a predetermined time from when it reaches the position of the roller 51A until it reaches the molten pool WY. During this predetermined time, the predetermined portion xa generates heat due to its resistance and gradually increases in temperature, and the temperature increases toward the tip side. Here, the predetermined time is the length of the energized portion of the filler wire X (the portion between the position of the filler wire X in contact with the roller 51A and the tip of the filler wire X (contact portion with the welded portion)). It is a time obtained by dividing the above by the predetermined speed.

  Then, in a state where the filler wire X is being fed at a predetermined speed as shown in FIG. 10, if the roller 51A is moved ΔL in a direction away from the tip of the wire X as shown in FIG. The length also increases from L1 to L2 (L1 + ΔL). Therefore, the energization time for the predetermined portion xa becomes longer. As a result, as shown in FIG. 12A, the temperature rise amount of the predetermined portion xa increases from ΔT1 to ΔT2 corresponding to the change in the length of the energized portion. Become. As a result, as shown in FIG. 12B, the tip temperature of the filler wire X (the temperature immediately before contacting the molten pool WY) is, for example, T0 before the wire X is heated. When the length is L1, it rises to T1, and when the length of the energized portion is L2, it rises to T2, which is (ΔT2−ΔT1) higher than T1. That is, the tip temperature of the filler wire X can be arbitrarily controlled by moving the roller 51A in the longitudinal direction of the wire X so that the distance from the tip of the filler wire X changes. In addition, when the material of the filler wire X is, for example, iron, by controlling the tip temperature of the wire X to be approximately 1400 degrees, which is slightly lower than the melting point, for example, the end of the filler wire X is placed in the molten pool WY. Stable and good meltability when contacted can be ensured.

  When the length of the energized portion of the filler wire X is changed, the circuit resistance of the filler wire heating device as a whole changes, so that the energized current changes. However, the resistance value RX of the energized portion of the filler wire X is the total resistance RO of the circuit for energizing this filler wire X (the resistance of the cables 32 and 33 for connecting to the filler wire X as shown in FIG. 13). RL1, RL2, resistance RP of metal plates W1, W2 to be welded, resistance RY of molten pool WY, contact resistance Rt1 of molten pool WY and filler wire X, contact resistance Rt2 of filler wire X and roller 51A, roller Compared to the contact resistance Rt3 between 51A and the electrode 55, the resistance value RD of the heating power supply device 31, and the resistance value RX of the filler wire X portion), it is sufficiently small (RX << RO). Therefore, when the output voltage V of the power supply device 31 is constant, even if the length of the energized portion is changed, the fluctuation of the total resistance RO is slight, and as a result, the current value (= V / RO) There is also little change. That is, since almost the same value of current flows through the filler wire X as before the change, the heat generation per unit time in the predetermined portion xa of the filler wire X is substantially constant regardless of the change in the length of the energized portion.

  On the other hand, when the rollers 51A and 51B are moved in this manner and the images are sequentially analyzed, if the bending of the filler wire X or the displacement of the nozzle 11 is not detected, the rollers 51A and 51B are The roller moving motor 65 is driven so as to return to the initial position indicated by. By doing so, the length of the portion through which the current flows in the filler wire X is shortened. Therefore, the temperature of the end portion of the filler wire X is lowered.

  As described above, according to the present embodiment, the length of a portion (a current-carrying portion) through which a current flows through the filler wire X is changed to control the temperature of the end portion of the filler wire X. It can improve so that the connection state of W1 and W2 may become favorable.

  Further, by analyzing the image captured by the imaging device 110 and analyzing the state of penetration of the filler wire X into the molten pool WY (the welded portion) including the molten pool WY, the connection between the metal plates W1 and W2 is performed. The state is determined. Then, the roller 51A is moved based on the determination result. Thereby, welding according to an infiltration state is attained during laser welding.

  Further, since the rollers 51A and 51B that support the filler wire X so as to be movable constitute an electrode (first electrode in the claims) for energizing a portion near the end of the filler wire X, the filler wire X The current can be increased in the filler wire X while supporting the movement of X. That is, the electrode and the support can be shared by a single member, and the parts constituting the filler wire supply device 3 can be reduced.

(Other embodiments)
The embodiment described above is one aspect for carrying out the present invention, and can be realized in various aspects other than this.

  That is, in the embodiment, the rollers 51A and 51B are configured to move when the bending of the tip end of the filler wire X or the displacement of the nozzle 11 is detected based on the captured image of the imaging device 110. As shown in FIG. 14, when a speedometer 70 capable of measuring the wire supply speed is arranged in the case 41 of the wire heating head and it is detected that the wire supply speed is lower than a predetermined speed. In addition, the rollers 51A and 51B may be moved as shown in FIG. When the supply speed becomes slower than the predetermined speed, the end of the wire X is in contact with the metal plates W1 and W2 and the supply is hindered, for example, a bending or the like has occurred on the front end side of the filler wire X This is to detect this. The speedometer 70 includes a roller 71 that slides on the filler wire X in the vicinity of the rear end of the nozzle 11, for example, and can be configured by detecting the rotational speed of the roller 71.

  It is also possible to configure as shown in FIG. That is, the filler wire heating head 40 is coupled via the brackets 2A and 40A so as to be relatively rotatable with respect to the laser head 2, and an angle sensor 80 for detecting an angle formed by the brackets 2A and 40A is provided. When the angle sensor 80 detects an angle fluctuation of a predetermined value or more, the rollers 51A and 51B are moved as shown in FIG. When an angle variation of a predetermined value or more is detected, the end of the wire X is in contact with the metal plates W1 and W2 and the supply is hindered, that is, the tip of the filler wire X is bent. It is possible to detect this.

  In addition to the examples of FIGS. 14 and 15, a reaction force generated in the sleeve 11 when it is displaced is detected, and when the detected reaction force is greater than or equal to a predetermined value, as shown in FIG. May be moved.

  In the above-described embodiment, the roller 51A is used as an electrode that is in contact with the filler wire X to energize. You may make it move. In this case, the moving mechanism for moving the electrode can be configured in the same manner as the moving mechanism 60 described above. For example, the electrode can be moved by fixing the electrode to the support member 52 and moving the support member 52 by the moving mechanism 60.

  The moving mechanism 60 in the above embodiment is an example of an electrode moving unit in the claims, and has various modes as long as the rollers 51A and 51B can be moved in the longitudinal direction of the filler wire. Is available.

  In the above embodiment, the roller 51A (electrode) is moved away from the tip of the filler wire X from the initial position in FIG. 10 to the position shown in FIG. 11 when a predetermined condition is satisfied. The position may be an intermediate position between the initial position in FIG. 10 and the position in FIG. 11 so that the electrode 55 can approach the tip. In this case, for example, when the filler wire X is heated too much, the heating of the filler wire X can be suppressed.

  In the above embodiment, the filler wire X is positioned behind the laser beam irradiated site so that the end of the filler wire X comes into contact with the molten pool formed by the laser beam LB at the welded site and storing the molten metal. The filler wire X is melted with the heat of the molten pool when it is brought into contact with the molten pool. The present invention is also applicable to the case where the filler wire is melted by supplying the filler wire from above and irradiating the end of the filler wire with laser light. That is, by heating the filler wire in advance, the melting load due to the laser light is reduced and the meltability of the filler wire is improved.

  ADVANTAGE OF THE INVENTION According to this invention, the filler wire supply apparatus and supply method which can melt | fuse a filler wire favorably without having a bad influence on a laser welding state can be provided. Therefore, in addition to the automobile industry, it may be widely used in industries that require welding of metal members.

DESCRIPTION OF SYMBOLS 1 Laser welding apparatus 3 Filler wire supply apparatus 5 Clamp (2nd electrode)
6 Filler wire heating device (heating means)
11 Nozzle 31 Filler wire heating power supply device (energization means)
40 Filler wire heating head 51A First roller (first electrode)
60 moving mechanism (electrode moving means)
100 Control unit (judgment means)
110 Imaging device (imaging means)
L Laser beam irradiated part LB Laser light R Welding path X Filler wire W1 Upper metal plate W2 Lower metal plate WK Molten hole WY Molten pool Wy Molten metal Z Gap

Claims (6)

A filler wire supply device that supplies a filler wire at a predetermined speed so that an end portion thereof is in contact with a portion to be welded by a laser beam that moves relative to a plurality of metal members along a predetermined welding path. And
Having heating means for heating the filler wire;
The heating means includes a first electrode that is in contact with an end portion of the filler wire, a second electrode that is in contact with the metal member, and a filler wire and a metal member between the first electrode and the second electrode. And an electrode moving means for moving the first electrode while maintaining contact with the filler wire so that a distance between the first electrode and the end of the filler wire changes. A filler wire supply device in laser welding, comprising: In the filler wire supply apparatus in laser welding according to claim 1,
Imaging means for imaging the welded part;
Analyzing the image picked up by the image pickup means, and determining the connection state between the metal members by analyzing the state of penetration of the filler wire into the welded portion,
The filler wire supply apparatus in laser welding, wherein the electrode moving means moves the first electrode based on a determination result of the determination means. In the filler wire supply apparatus in laser welding according to claim 2,
The determination unit determines that the connection state between the metal members is not good when detecting a bending of the filler wire more than a predetermined based on the image captured by the previous imaging unit,
Filler wire supply in laser welding, wherein the electrode moving means moves the first electrode in a direction away from the end of the filler wire when the determination means determines that the connected state is not good. apparatus. In the filler wire supply apparatus in the laser welding according to any one of claims 1 to 3,
The filler wire supply device in laser welding, wherein the first electrode is constituted by a roller that supports the filler wire so as to be movable. In the filler wire supply device in laser welding according to any one of claims 1 to 4,
The filler wire supply means is arranged so that the filler wire is placed behind the laser beam irradiated site so that the end of the filler wire is in contact with a molten pool formed at the site to be welded by the laser beam and storing molten metal. A filler wire supply device in laser welding, wherein the filler wire is supplied at the position of. A filler wire supply method for supplying a filler wire at a predetermined speed so that an end portion follows a welded portion by a laser beam that moves relative to a plurality of metal members along a predetermined welding path,
Having a heating step of heating by energizing the filler wire;
The heating step energizes the filler wire and the metal member between the first electrode that contacts the vicinity of the end of the filler wire and the second electrode that contacts at least one of the metal members. Moving the first electrode while maintaining contact with the filler wire so that the distance between the first electrode and the end of the filler wire changes when a predetermined state is established. A filler wire supply device for laser welding.