JP2004114121A - Laser beam welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the technique that enables welding of a tubular body to be surely performed even in a narrow space and that also prevents a welding head and optical fibers from being damaged in welding. <P>SOLUTION: The laser beam welding equipment is provided with an outer frame 40 which is fixed with a clamping claw on the tubular body 20 to be welded, an inner frame 50 which is rotatably driven around the axis of the tubular body 20 inside the outer frame 40, and a welding head body 70 which is attached to the inner frame 50. Then, the welding head body 70 and an optical fiber 11 for feeding a laser beam to the body are connected freely rotatably around the axis of the optical fiber 11. In addition, an angle of advance can be imparted to the laser beam emitted from a nozzle. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser welding apparatus suitable for use in piping welding or the like.
[0002]
[Prior art]
In welding pipe joints, etc., it is necessary to weld the pipe in the entire circumferential direction. As an apparatus capable of performing such welding, there is a multi-axis laser welding apparatus. A multi-axis, for example, 5-axis laser welding apparatus, allows the workpiece to be welded and the welding head to move relative to each other in three directions X, Y, and Z that are orthogonal to each other. (See, for example, Patent Document 1). In such a laser welding apparatus, the welding head rotates around the axis while turning around the pipe, so that the welding direction always faces the peripheral surface of the pipe.
[0003]
[Patent Document 1]
JP-A-8-215874 (page 8, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, for example, in the case of welding a pipe group in which pipes with a diameter of 30 mm are arranged at a pitch of 90 mm, the space in which the welding head enters is limited, so that the above-described laser welding apparatus can perform welding. There is a problem that you can not.
[0005]
Further, as another problem, during laser welding, spatter occurs when laser light is irradiated onto the object to be welded, but there is a problem that this sputter damages the optical system of the laser welding apparatus. In addition, the metal vapor is turned into plasma at the time of welding, and since this plasma is very high in temperature, there is also a problem that the welding head is thermally damaged particularly at the time of welding in a narrow portion.
[0006]
In the case of a pipe or the like, the head of the laser welding apparatus rotates around the pipe. At this time, the optical fiber that feeds the laser beam to the head is twisted. For this reason, there is a possibility that the number of rotations of the head during welding may be limited, or damage or the like may occur in the optical fiber or the joint portion of the optical fiber.
[0007]
The present invention has been made based on such a technical problem, and an object of the present invention is to provide a laser welding apparatus that can reliably weld a pipe body even in a narrow space.
Another object is to provide a technique capable of preventing damage to a welding head and an optical fiber during welding.
[0008]
[Means for Solving the Problems]
For this purpose, in the laser welding apparatus of the present invention, the laser head revolves around the object to be welded clamped by the clamp part, and the laser light source feeds the fiber from the nozzle provided in the laser head. The emitted laser beam is emitted. That is, when the laser head revolves, the nozzle always rotates around the welding target in a state of facing the welding target. At this time, the laser head irradiates the welding object with laser light from the nozzle at a predetermined inclination angle.
In addition, the laser head includes an optical system in which the focal position of the laser beam is in the vicinity of the opening of the nozzle, so that the laser head is positioned at the opening of the nozzle as compared with the case where the focal position of the laser beam is aligned with the welding target as usual. The laser beam diameter can be reduced.
Further, the nozzle can be cooled by a cooling mechanism.
In addition, a connecting member that rotatably connects the fiber side and the nozzle side around the axis of the fiber can be provided between the fiber and the nozzle. The position of the connecting member may be a connection portion between the fiber and the laser head, or may be inside the optical system provided in the laser head. In other words, as long as the fiber side and the nozzle side are rotatably connected, any part between the fiber and the nozzle may be used.
By the way, the laser welding apparatus as described above can be applied to any type as long as the laser head revolves around the welding target clamped by the clamp portion as a track. For example, as will be described later, it may be a welding device dedicated to a tubular body that welds another tubular body to a tubular body already fixed in a tube group in which a large number of tubular bodies are arranged. A multi-axis laser welding apparatus may be used. Regardless of the configuration, the laser head irradiates laser light from the nozzle at a predetermined inclination angle to the object to be welded, so that spatter and plasma generated during welding hardly rebound to the head.
[0009]
The present invention can also be understood as a laser welding apparatus dedicated to a tubular body. That is, this laser welding apparatus includes a clamp portion that clamps a tube to be welded, a frame that is rotatably provided around the axis of the tube with respect to the clamp portion, and a laser that is provided on the frame and is applied to the tube. A laser head including a nozzle for irradiating light, and a fiber for supplying laser light from a laser light source to the laser head. In such a laser welding apparatus, the frame rotates around the axis of the tube body with respect to the clamp portion fixed to the tube body by clamping the tube body, and laser is emitted from the nozzle of the laser head provided on the frame. By irradiating light, the outer peripheral surface of the tubular body can be welded in the circumferential direction. Such a laser welding apparatus is particularly suitable for welding a pipe body in a pipe group.
At this time, the laser head preferably irradiates the tube to be welded with laser light at a predetermined inclination angle.
Also, if a connecting member is provided between the fiber and the nozzle so that the fiber side and the nozzle side can be rotated about the fiber axis, the fiber side can be prevented from twisting even when the laser head rotates together with the frame. it can. That is, when the frame rotates (rotates) around the axis of the tube, the laser head attached to the frame revolves around the axis of the tube. At this time, if the fiber is fixed to the laser head, the fiber rotates around the axis of the fiber while revolving around the axis of the tube, thereby twisting the fiber. By providing the connecting member, this rotation of the fiber can be avoided.
Further, the laser head can be attached to the frame so as to be rotatable around the optical axis of the laser light emitted from the nozzle. Moreover, a through-hole having a diameter larger than that of the fiber can be formed in the frame, and the fiber can be passed through in a loosely fitted state.
[0010]
Moreover, such a laser welding apparatus can be configured to form a slit in the frame that guides the tube to be welded from the outside of the frame to a position where the tube is clamped by the clamp portion.
Furthermore, a fixed frame integrated with the clamp portion may be provided, and the above-described frame may be configured to rotate within the fixed frame. In this case, it is preferable to form slits in the fixed frame as well as the frame.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a perspective view for explaining the configuration of a welding head portion of a laser welding apparatus according to the present embodiment, FIG. 2 is a front sectional view of the welding head portion, FIG. 3 is a plan sectional view of FIG. FIG. 3 is a right side view of FIG. 2.
As shown in FIG. 1, a laser welding apparatus 10 includes a laser light source (not shown), an optical fiber (fiber) 11 that feeds laser light from the laser light source, and laser light fed through the optical fiber 11. The welding head part 30 which irradiates the tubular body 20 to be welded and a controller (not shown) for controlling the operation of the welding head part 30 are provided.
[0012]
Here, the pipe body 20 has a predetermined length, for example, a diameter of 30 mm, and a plurality of pipes 20 are welded by the laser welding apparatus 10 to form a pipe group in which a large number of pipes are arranged at a pitch of 90 mm. To do.
[0013]
As shown in FIGS. 1 to 4, the welding head portion 30 includes an outer frame 40 configured in a substantially cylindrical shape, and an inner frame (frame) 50 housed in the outer frame 40 so as to be rotatable around its axis. A drive mechanism 60 that rotates the inner frame 50 and a welding head main body (laser head) 70 provided in the inner frame 50 are provided.
[0014]
The outer frame 40 has a substantially cylindrical shape as a whole, and includes frame rings 41A and 41B having substantially outer shapes and joint members 42 that integrally connect the frame rings 41A and 41B.
The frame rings 41 </ b> A and 41 </ b> B are each formed with a notch (slit) 43 through which the tubular body 20 to be welded is inserted, thereby forming a substantially C shape. The joint member 42 has a function of fixing the frame rings 41A and 41B so as to face each other with a predetermined distance therebetween. As shown in FIG. 1, a plurality of bar members (or pipe members) may be used. It is good also as a cylindrical wall material which covers the outer peripheral surface. In either case, the portion corresponding to the notch 43 needs to be an opening for guiding the tubular body 20.
As shown in FIGS. 2 and 3, the frame ring 41 </ b> B is integrally provided with a plate 44 inside thereof, and the plate 44 has a substantially U-shape for allowing the tube body 20 to be inserted therethrough. A notch 44a is formed at a position corresponding to the notch 43 of the frame ring 41B. The plate 44 is integrally provided with a pair of clamp claws (clamp portions) 45 that clamp the tube body 20 outside the outer frame 40. As shown in FIG. 4, the pair of clamp claws 45 are formed so that the opposing surfaces 45 a on the inside thereof are formed in a substantially square shape, and the tube body 20 is clamped at a total of four points by the clamp claws 45 on both sides. It has become. The pair of clamp claws 45 may be configured to be opened and closed by a drive mechanism (not shown), but may be a fixed type and the tube body 20 may be passed between the clamp claws 45.
[0015]
The inner frame 50 has a generally cylindrical shape as a whole, and includes a pair of substantially circular end plates 51A and 51B and a joint member 52 that integrally connects the end plates 51A and 51B. The end plates 51A and 51B are formed with substantially U-shaped notches (slits) 53 through which the tubular body 20 to be welded is inserted. Further, substantially circular gear teeth 54 are integrally provided on the outer peripheral portions of the end plates 51A and 51B, respectively.
The joint member 52 has a function of fixing the end plates 51A and 51B so as to face each other with a predetermined distance therebetween. As shown in FIG. 1, a plurality of bar members (or pipe members) may be used. It is good also as a cylindrical wall material which covers the outer peripheral surface. In either case, the portion corresponding to the notch 53 needs to be an opening for guiding the tube body 20.
The inner frame 50 is rotatable around its axis within the outer frame 40 by interposing a bearing or the like with the outer frame 40 as necessary.
[0016]
As shown in FIG. 1, the drive mechanism 60 is for rotating the inner frame 50 within the outer frame 40, and includes a head rotation motor 61 provided outside the outer frame 40 and a drive transmission gear 62. It consists of and. The head rotation motor 61 has a drive gear 61a that meshes with gear teeth 54 (see FIG. 3) provided on the end plate 51A of the inner frame 50. The drive transmission gear 62 includes a driven gear 62b that meshes with the drive gear 61a at one end of the shaft 62a, and a drive gear 62c that meshes with gear teeth 54 (see FIG. 3) provided on the end plate 51B at the other end of the shaft 62a. Yes.
In such a drive mechanism 60, by rotating the head rotation motor 61, the rotational driving force is transmitted to the end plates 51A and 51B of the inner frame 50 via the drive gear 61a and the drive transmission gear 62. As a result, as shown in FIG. 5, the inner frame 50 rotates within the outer frame 40 that is fixed to the tubular body 20 to be welded by the clamp claws 45.
[0017]
As shown in FIG. 6, the welding head main body 70 includes an optical system 71 to which laser light fed from a laser light source is guided by an optical fiber 11, and a nozzle 72 that irradiates laser light through the optical system 71 to the outside. Is provided.
The welding head main body 70 is arranged with the nozzle 72 facing the center side of the inner frame 50. The welding head main body 70 is attached to the joint member 52 of the inner frame 50 via a bearing 73 provided on the side opposite to the nozzle 72. The welding head main body 70 is around the central axis of the nozzle 72 (see FIG. 2, it is rotatable in the direction of arrow (A) in FIG. Thereby, when the welding head main body 70 to which the optical fiber 11 is connected rotates together with the inner frame 50 as will be described later, the welding head main body 70 is rotated around the bearing 73 by being pulled by the non-rotating optical fiber 11. (Oscillation) is possible.
[0018]
Further, an optical fiber 11 that feeds laser light to the welding head main body 70 is connected to the welding head main body 70 via a bearing (connecting member) 74 that is rotatable around the axis of the optical fiber 11 at the tip. ing. Thereby, the welding head main body 70 and the optical fiber 11 are rotatably connected around the axis of the optical fiber 11. As a result, the optical fiber 11 is not affected even if the welding head body 70 rotates about the axis of the inner frame 50 (in the direction of the arrow (b) in FIGS. 2 and 6) as the inner frame 50 rotates. It will not be twisted around the axis. The optical fiber 11 passes through a through hole 55 formed in the end plate 51 </ b> A of the inner frame 50. The through hole 55 has a diameter larger than the outer diameter of the optical fiber 11 by a predetermined size, whereby the optical fiber 11 penetrates the end plate 51A in a loosely fitted state. Thereby, when the welding head main body 70 rotates around the bearing 73, the bending radius of the optical fiber 11 at this portion can be increased.
[0019]
Now, as shown in FIG. 7, in the welding head main body 70 as described above, the laser light emitted from the nozzle 72 gives a forward angle (inclination angle) θ to the tubular body 20 to be welded. It comes to be irradiated with. More specifically, the attachment angle of the welding head main body 70 to the inner frame 50 as shown in FIG. 6 or the optical system 71 is set in accordance with the advance angle θ. However, since the welding head main body 70 can rotate around the bearing 73 in the present embodiment, the former attachment angle of the welding head main body 70 to the inner frame 50 is set in accordance with the advance angle θ. Is preferred.
[0020]
Further, as shown in FIG. 8, the laser light emitted from the nozzle 72 of the welding head body 70 is set so that the diameter of the laser light is reduced by focusing at the portion of the opening 72 a of the nozzle 72. ing. The inner diameter of the opening 72a of the nozzle 72 is set to a minimum size according to the narrowed laser beam diameter.
The nozzle 72 has a cooling medium flow path (cooling mechanism) 76 made of a gas or liquid for cooling the nozzle 72. A cooling medium supplied from a cooling medium supply source (not shown) circulates in the flow path 76.
The nozzle 72 is preferably formed using a metal material having high thermal conductivity or high heat resistance such as copper, tungsten, or platinum.
[0021]
In the laser welding apparatus 10 having the above-described configuration, as shown in FIG. 5A, the notch 43 of the outer frame 40 and the notch 53 of the inner frame 50 are matched with each other, as shown in FIG. The pipe body 20 (hereinafter referred to as the existing pipe body 20) that is already installed is passed between the pair of clamp claws 45, and the outer frame 40 is fixed to the existing pipe body 20.
Next, the pipe body 20 to be welded to the existing pipe body 20 is introduced into the inner frame 50 from the cutout 43 of the outer frame 40 and the cutout 53 of the inner frame 50.
Then, as shown in FIGS. 5A to 5C, the head rotation motor 61 of the drive mechanism 60 is operated in a state where the pipe body 20 to be welded is appropriately positioned with respect to the existing pipe body 20. The inner frame 50 is rotated (rotated). Then, the welding head main body 70 attached to the inner frame 50 rotates (revolves) around the joint between the existing pipe body 20 and the pipe body 20 to be welded.
At this time, a laser beam fed from a laser light source (not shown) through the optical fiber 11 is irradiated from the nozzle 72 to the joint between the existing tube 20 and the tube 20 to be welded. As a result, as shown in FIG. 9, the welding head main body 70 irradiates the seam portion with laser light while turning around the existing pipe body 20 and the pipe body 20 to be welded. And the pipe 20 to be welded can be welded together.
That is, by using such a laser welding apparatus 10, it is possible to automatically weld the pipe bodies 20 constituting the pipes arranged with a small diameter and a narrow pitch.
[0022]
At this time, as shown in FIG. 7, the laser light emitted from the nozzle 72 is given a forward angle θ, whereby the existing pipe body 20 to be welded and the pipe body 20 to be welded are Spatter generated when the laser beam is irradiated to the joint of the nozzle jumps mainly in a direction different from the opening 72a of the nozzle 72, thereby preventing the optical system 71 in the welding head body 70 from being damaged. it can. Further, even if the metal vapor is turned into plasma during welding, the plasma can be prevented from entering the nozzle 72 for the same reason, and the welding head main body 70 can be prevented from being thermally damaged. In addition, by irradiating the laser beam with the laser beam inclined, it is possible to improve the escape of bubbles (porosity) and improve the welding quality.
Further, as shown in FIG. 8, the laser beam emitted from the nozzle 72 has the narrowest light diameter at the opening 72a. Thereby, since the opening diameter of the opening 72a can be minimized, the entry of the above-described spatter, plasma, and welding fume into the welding head main body 70 can be prevented also in this respect. Of course, since the assist gas is ejected from the nozzle 72 together with the laser beam, a more effective effect can be obtained together with this.
In addition, the nozzle 72 is formed of a material having high thermal conductivity or high heat resistance, and further has a flow path 76 for the cooling medium. Can do.
[0023]
Further, in the above configuration, as shown in FIG. 6, the optical fiber 11 is connected to the welding head main body 70 via the bearing 74, whereby the welding head main body 70 and the optical fiber 11 are connected to the optical fiber 11. It is connected rotatably around the axis of Therefore, even if the welding head main body 70 rotates together with the inner frame 50 around the axis of the inner frame 50 (in the direction of the arrow (b) in FIGS. 2 and 6), the optical fiber 11 does not follow the rotation trajectory of the welding head main body 70. Therefore, the optical fiber 11 itself is not twisted around the axis line only by the tip portion swinging. As a result, the welding head main body 70 can be reliably welded without limiting the number of rotations, and damage to the optical fiber 11 and its connecting portion can be prevented.
Further, the optical fiber 11 passes through a through hole 55 formed in the end plate 51 </ b> A of the inner frame 50 and having a diameter larger than the outer diameter of the optical fiber 11. Further, the welding head main body 70 is connected to the inner frame 50 via a bearing 73. As a result, when the inner frame 50 and the welding head main body 70 rotate during welding, the welding head main body 70 swings around the bearing 73 by the force received from the optical fiber 11 that does not rotate. By swinging the welding head main body 70 and the optical fiber 11 passing through the large-diameter through hole 55, a large bending radius of the optical fiber 11 can be secured, and the force applied to the optical fiber 11 is reduced. be able to. Accordingly, it is possible to prevent damage to the optical fiber 11 and its connecting portion.
[0024]
In the above-described embodiment, one welding head main body 70 is provided in the inner frame 50. However, a configuration in which a plurality of the welding head main bodies 70 are provided is also possible.
Moreover, in the said embodiment, although it has the structure by which the bearing 74 was interposed in the connection part of the optical fiber 11 and the welding head main body 70, as shown to Fig.10 (a), not only this but welding. A bearing 74 is provided in the middle of the optical system 71 of the head body 70, the optical fiber 11 side is integrated with the optical fiber 11 with respect to the bearing 74, and only the nozzle 72 side is rotated integrally with the inner frame 50 with respect to the bearing 74. You can also Furthermore, as shown in FIG. 10 (b), other configurations are appropriately adopted, such as a configuration in which bearings 74 are respectively provided in the connection portion of the optical fiber 11 and the welding head body 70 and in the middle of the optical system 71. Can also be adopted. In particular, the configuration as shown in FIG. 10B is particularly effective when a plurality of optical fibers 11 are connected.
By the way, in the said embodiment, although it was set as the structure which welds the pipe body 20 from the outer peripheral side in the laser welding apparatus 10, the pipe body 20 is provided by providing the nozzle 72 of the welding head main body 70 toward an outer peripheral side. It is also possible to adopt an apparatus configuration for welding from the inside.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.
[0025]
【The invention's effect】
As described above, according to the present invention, it is possible to reliably weld the pipe body even in a narrow space.
Further, by applying a forward angle to the laser beam at the time of welding and irradiating the object to be welded, it is possible to prevent damage to the welding head or the like at the time of welding and improve the welding quality. Further, by providing a connecting member between the optical fiber and the nozzle, it becomes possible to prevent twisting of the optical fiber and to prevent damage to the optical fiber or the like.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a welding head portion of a laser welding apparatus in the present embodiment.
FIG. 2 is a front sectional view of a welding head portion.
FIG. 3 is a plan sectional view of FIG. 2;
4 is a right side view of FIG. 2;
FIG. 5 is a view showing a state in which an inner frame and a welding head main body rotate around a pipe body.
FIG. 6 is a cross-sectional view showing a configuration of a welding head main body.
FIG. 7 is a view showing a state in which a laser beam is irradiated with an advancing angle in the welding head main body.
FIG. 8 is an enlarged view of a nozzle.
FIG. 9 is a view showing a state in which the welding head main body performs welding while rotating around the pipe body.
FIG. 10 is a view showing another example of a laser welding apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Laser welding apparatus, 11 ... Optical fiber (fiber), 20 ... Tube (welding object), 30 ... Welding head part, 40 ... Outer frame, 43 ... Notch (slit), 45 ... Clamp claw (clamp part) 50 ... Inner frame (frame), 53 ... Notch (slit), 55 ... Through hole, 60 ... Drive mechanism, 70 ... Welding head body (laser head), 71 ... Optical system, 72 ... Nozzle, 72a ... Opening 73 ... Bearings, 74 ... Bearings (connection members), 76 ... Flow path (cooling mechanism), θ ... Advancing angle (inclination angle)

Claims (10)

A clamp part for clamping a welding object;
A laser head that revolves around the welding object clamped in the clamp part as a track,
A fiber for supplying laser light from a laser light source to the laser head;
A nozzle that is provided in the laser head and emits a laser beam fed by the fiber;
With
The laser welding apparatus, wherein the laser head irradiates the welding object with laser light at a predetermined inclination angle from the nozzle. The laser welding apparatus according to claim 1, wherein the laser head includes an optical system that sets a focal position of the laser light in the vicinity of the opening of the nozzle. The laser welding apparatus according to claim 1, wherein the laser head includes a cooling mechanism that cools the nozzle. 2. The laser welding apparatus according to claim 1, wherein a connecting member is provided between the fiber and the nozzle to connect the fiber side and the nozzle side so as to be rotatable around an axis of the fiber. A laser welding apparatus for welding pipes,
A clamp for clamping the tube to be welded;
A frame provided to be able to rotate around the axis of the tubular body with respect to the clamp part;
A laser head provided on the frame and provided with a nozzle for irradiating the tube with laser light;
A fiber for supplying laser light from a laser light source to the laser head;
A laser welding apparatus comprising: The laser welding apparatus according to claim 5, wherein the laser head irradiates the tube to be welded with a laser beam at a predetermined inclination angle. 6. The laser welding apparatus according to claim 5, wherein a connecting member is provided between the fiber and the nozzle to connect the fiber side and the nozzle side so as to be rotatable around the axis of the fiber. The laser welding apparatus according to claim 5, wherein the laser head is attached to the frame so as to be rotatable around an optical axis of laser light emitted from the nozzle. 6. The laser welding apparatus according to claim 5, wherein a through-hole having a diameter larger than that of the fiber is formed in a portion where the fiber passes through the frame. 6. The laser welding apparatus according to claim 5, wherein a slit is formed in the frame to guide the tube to be welded from a position outside the frame to a position where the tube is clamped by the clamp portion.

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