JP2006007237A - Work clamping device for laser beam welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work clamping device for laser beam welding, which efficiently performs press and restrain work to correct a welding portion and efficiently supplies an assist gas when welding a wide area by a remote laser beam welding. <P>SOLUTION: A clamping tool 6, which presses and restrains the welding portion of a work W being driven backward and forward by a clamping cylinder 11, is provided. A gas chamber part 12 is formed by making a hole at a portion of the clamping tool 6 corresponding to the position where a weld bead Bw is formed, and further an assist gas introducing passage 13 communicating to the gas chamber part 12 is provided. The assist gas is introduced into the gas chamber part 12 through the assist gas introducing passage 13, and the assist gas is previously stayed in the gas chamber part 12 under a condition that the weld portion is pressed and restrained by the clamping tool 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a work clamp apparatus that pressurizes and restrains a welded part of a work to be welded so as to eliminate a gap prior to laser welding when performing laser welding in the form of a lap joint, for example.

  The laser welding equipment used in the mass production process uses, for example, a multi-degree-of-freedom welding robot as a welding machine and a laser processing head (welding torch) at the tip of the welding robot, while being able to transmit with a fiber cable. The mainstream is that the laser beam is irradiated from the processing head to the welding site using, for example, if the welding points are scattered over a wide range, for example, it takes time to move the processing head, It is impossible to cope with the welding of a part where the machining head interferes, such as a narrow groove.

Therefore, in recent years, remote laser (scanner laser) welding, in which a relatively long-focus laser beam is reflected by a mirror and the angle of the mirror is variably controlled to move the laser beam instantaneously to perform welding. A technique called a law is proposed in Patent Document 1 and the like.
Japanese Patent Laying-Open No. 2003-145285 (FIG. 1)

  In the remote laser welding method, the laser beam can be moved to a distant welding point in a short time by moving a mirror. However, as described above, when the welding point is scattered over a wide area, the same method is used to correct the welding site. In addition to increasing the size of the device that pressurizes and restrains the part, it is necessary to inject a large amount of assist gas (inert gas such as Ar and He) for stabilizing the welding quality over a wide range, There is still room for improvement in terms of simplification and cost reduction.

  The present invention has been made paying attention to such problems, and in particular, when performing a wide range of welding by the remote laser welding method, it is possible to efficiently perform pressurization restraint and supply of assist gas for correcting the welding site. An object of the present invention is to provide a work clamping device for laser welding.

  The invention according to claim 1 is a work clamping device that pressurizes and restrains the welded part of the work prior to the laser welding when irradiating the welded part of the work with a laser beam. A clamp jig that pressurizes and restrains the welded part of the workpiece by being driven back and forth is formed, and a hole is formed in a portion corresponding to the weld bead formation position in the clamp jig to form a gas chamber portion, and gas An assist gas introduction passage communicating with the chamber portion is provided, and the assist gas is introduced into the gas chamber portion through the gas introduction passage, so that the assist gas is retained in the gas chamber portion in a pressurized restraint state of the welding portion by the clamp jig. It is characterized by that.

  As the basic welding method, the remote laser welding method capable of instantaneously moving the laser beam as described above is preferable, but is not necessarily limited to the remote laser welding method.

As a laser beam, for example, a CO ₂ laser is used in addition to a YAG laser, and an inert gas such as Ar (argon) or He (helium) is used as an assist gas.

  Therefore, in the present invention, the clamp jig effectively presses and restrains a wide range of welded parts and corrects the same parts. And in the pressurization restraint state by the clamp jig, while the gas chamber part formed in the clamp jig allows the passage of the laser beam, the assist gas is preliminarily retained in the gas chamber part. Becomes an inactive state, and it is possible to stabilize the welding quality.

  According to the first aspect of the present invention, since the clamp jig also has a function as a gas chamber part for retaining the assist gas, the facility can be downsized and simplified. By keeping the assist gas in the gas chamber, it is not necessary to inject the assist gas continuously and in large quantities, and it is possible to contribute to cost reduction by reducing the amount of gas used and eliminating waste.

  1 and subsequent drawings show a preferred embodiment of the present invention. In particular, FIG. 1 shows a schematic configuration of a remote laser welding method, and FIG. 2 shows an enlarged view of a main part of FIG.

  In the remote laser welding method, as shown in FIG. 1, a laser beam Lb oscillated from a laser oscillator 1 is guided to two movable mirrors 3 and 4 by a conduit 2 with a built-in mirror. By variably controlling the angle, the laser beam Lb is guided to a predetermined welding portion of the work W, which is the workpiece to be welded, to perform welding. Each of the mirrors 3 and 4 has uniaxial or biaxial variable degrees of freedom, and the variable degrees of freedom of these mirrors 3 and 4 are not limited to instantaneous movement of the welded part, but also at a specific welded part. It is used for continuous movement of the laser beam irradiation position.

  FIG. 2 shows a work lamp apparatus for laser welding as a detail of FIG. 1, and an outer panel Pa and an inner panel Pb are superposed on a block-shaped set jig 5 with a pair of left and right flange portions F, F. The workpiece W is positioned in a horizontal posture. Then, in order to eliminate the gap between the flange portions F and F of the workpiece W and correct this, the flange portion F and F of the workpiece W is pressed against the set jig 5 with the clamp jig 6 and clamped. Laser welding is performed in the form of a so-called lap joint by irradiating the laser beam Lb to the flange portions F and F as welding parts in the state.

  In FIG. 2, the clamp jig 6 is drawn only for the overlapped portion between the flange portions F and F on one side, but the clamp jig 6 is similarly arranged for the overlapped portion between the other flange portions F and F. It goes without saying that it is done.

  The clamp jig 6 is formed by extending a pair of arms 8 integrally with a flat bar-shaped holding plate 7, and the arms 8 are rotatably supported by a fixed bracket 10 via hinge pins 9. In addition, the arm 8 is connected to a piston rod 12 of a pair of clamp cylinders 11 serving as driving means. As a result, the clamp jig 6 pivots according to the expansion and contraction operation of the clamp cylinder 11, that is, moves forward and backward with respect to the flange portions F and F on the set jig 5, and pressurizes and restrains the flange portions F and F. It is supposed to be.

  In this embodiment, as apparent from FIG. 2, it is assumed that laser welding is intermittently performed at three locations along the longitudinal direction of the flange portions F and F, and the holding plate of the clamp jig 6 In the portion corresponding to the actual welding position of 7, three holes are formed to form mutually independent gas chamber portions 12, 12.

  The gas chamber portions 12 and 12 are not only the regions that allow the laser beam Lb to pass during laser welding as described above, but finally a weld bead Bw is formed as shown in FIGS. 3 and 4 in addition to FIG. The space is large enough to store the assist gas necessary to inactivate the periphery of the weld bead Bw. The holding plate 7 has an assist gas introduction passage 13 communicating with the gas chamber portions 12, 12, and a tube 15 is connected to an introduction port 14 that is an open end of the assist gas introduction passage 13. An inert gas such as Ar (argon) or He (helium) is supplied as an assist gas from a gas supply source such as a gas cylinder (not shown).

  Therefore, according to the work clamping apparatus for laser welding configured as described above, FIG. 2 shows a state in which the clamp jig 6 clamps the flange portions F and F, but the clamp jig 6 is unclamped. In a state, that is, in a state where the arm 8 of the clamp jig 6 is in an upright posture, the workpiece W is put on the set jig 5 and positioned.

  When the workpiece W is positioned on the set jig 5, the clamp jig 6 is in a clamped state as shown in FIG. 2, and pressurizes and restrains the flange portions F and F of the workpiece W. Prior to actual welding, an assist gas such as Ar is introduced into the gas chamber portions 12 and 12 through the assist gas introduction passage 13 to be fully filled or retained. In this case, since Ar is heavier than air, it is advantageous in that it stays in the gas chamber portions 12 and 12 itself to make the atmosphere in the vicinity of the welding position an inert atmosphere. Therefore, if the assist gas is filled or retained in the gas chambers 12 and 12, there is no need to continuously supply the assist gas.

  If the assist gas is introduced into each gas chamber portion 12, 12, the laser beam is supplied to the flange portions F, F through the gas chamber portions 12, 12 for each gas chamber portion 12, 12 by the remote laser welding method described above. Laser welding is performed by irradiating Lb. That is, the penetration S as shown in FIG. 5 can be made at the laser beam irradiation position for each gas chamber portion 12 and 12, and finally the weld bead Bw is formed as the movement locus of the laser beam Lb as shown in FIG. Thus, laser welding is performed.

  In this case, not only the continuous movement of the laser beam Lb in the gas chamber parts 12 and 12 but also the moment of the laser beam Lb from the first gas chamber part 12 to the second gas chamber part 12, for example. This movement is performed by variable control of the angles of the mirrors 3 and 4 shown in FIG.

  As described above, according to the present embodiment, the clamping jig 6 that pressurizes and restrains the flange portions F and F of the workpiece W substantially connects the gas chamber portions 12 and 12 and the gas introduction passage 13. Since it has both, the downsizing and simplification of the equipment can be achieved. Moreover, by filling or retaining an assist gas such as Ar in the gas chambers 12 and 12 in advance, there is no need to continue supplying a large amount of gas, and laser welding with excellent welding quality can be performed with a small amount of gas used. Is possible.

  FIG. 6 is a diagram showing a second embodiment of the present invention, and the same reference numerals are given to portions common to FIG.

  In the second embodiment, in order to securely contain assist gas such as Ar in the gas chamber parts 12 and 12, a lid 14 is provided on the upper surfaces of the gas chamber parts 12 and 12, and the assist gas is substantially provided. The gas chambers 12 and 12 containing the gas are used as a sealed space.

  However, depending on the type of the laser beam Lb and the material of the lid 14, transmission of the laser beam Lb itself may be blocked by the lid 14, so that it is thin when a CO 2 laser is used as the laser beam Lb, for example. A lid 14 made of a zinc selenium plate (an alloy of zinc and selenium that transmits a CO2 laser) is used. When a YAG laser is used, a lid 14 made of a glass plate is used.

  According to the second embodiment, the gas chamber parts 12 and 12 are made more sealed, and the welding quality is further improved.

Explanatory drawing which shows the outline of the remote laser welding method used for this invention. The principal part perspective view which shows specific embodiment of the clamp apparatus for laser welding which concerns on this invention. The perspective view of the clamp jig | tool in FIG. Plane explanatory drawing of FIG. Sectional drawing in alignment with the AA of FIG. Sectional drawing which shows the 2nd Embodiment of this invention.

Explanation of symbols

3, 4 ... Mirror 5 ... Set jig 6 ... Clamp jig 7 ... Holding plate 11 ... Clamp cylinder (drive means)
12 ... Gas chamber 13 ... Assist gas introduction passage Bw ... Weld bead Lb ... Laser beam W ... Workpiece

Claims (5)

A workpiece clamping device that pressurizes and restrains the welded part of the workpiece prior to the laser welding when irradiating the welded part of the workpiece with a laser beam.
Provided with a clamp jig that pressurizes and restrains the welded part of the workpiece by being driven forward and backward by the drive means,
While forming a gas chamber part by making a hole in the part corresponding to the weld bead formation position in this clamping jig,
An assist gas introduction passage communicating with the gas chamber is provided,
Laser welding is characterized in that assist gas is retained in the gas chamber portion in a pressurized restraint state of a welding portion by a clamp jig by introducing assist gas into the gas chamber portion through the gas introduction passage. Work clamp device.   2. The laser welding work clamp device according to claim 1, wherein the welding site is horizontal, and laser welding is performed by irradiating a laser beam from above the horizontal welding site. A lid capable of transmitting a laser beam is provided on the upper surface of the gas chamber,
The work clamping device for laser welding according to claim 2, wherein the gas chamber portion is formed to be a sealed space in a state where the welding portion is pressed and restrained by a clamp jig.   The work clamp apparatus for laser welding according to any one of claims 1 to 3, wherein welding is performed by a remote laser welding method in which a laser beam is reflected by a mirror and guided along a welding locus. .   The work clamp apparatus for laser welding according to any one of claims 1 to 4, wherein welding is performed in the form of a lap joint.

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