JP2007216292A - Laser welding equipment and gap control method upon laser welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide laser welding equipment where a gap between both welding parts is controlled at high precision with a simple constitution, and laser welding can be surely performed. <P>SOLUTION: In this equipment, when the welding part 11 of a sill inner 10 and the welding part 21 of a floor panel 20 are confronted, and both the welding parts 11, 21 are lap-welded using laser welding equipment 1, the sill inner 10 is provided with an excitation means 100, the welding part 11 in the sill inner 10 is excited to attract the welding part 21 of the floor panel 20, and a gap δ between both the welding parts 11, 21 is almost fixedly held, thus, in the case both the welding parts 11, 21 are deformed to mutually separating directions owing to residual stress or the like by the application of heat upon laser welding, the gap δ between the welding parts 11, 21 can be almost fixedly held by the excitation means 100, so that the gap between both the welding parts 11, 21 can be controlled at high precision with a simple structure of providing the excitation means 100, and laser welding can be surely performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser welding apparatus and a method for controlling a gap between two welded members during laser welding.

  In laser welding, laser light is focused on a metal as a heat source, and the metal is locally heated and melted and then solidified before being joined. Laser welding is being applied to assembly welding, but it is not very common.

  As one of the reasons, it is necessary to manage the gap between the steel plates very strictly in the laser lap welding, and the gap is generally controlled to about 0.1 mm or less.

For this reason, conventionally, while pressing with the pressure roller from the upper side of the two members to be welded, the two members to be welded are attracted upward by the magnet roller. They are overlapped with no gap (see, for example, Patent Document 1).
JP 2004-66268 A (page 4, FIG. 1)

  However, in such a conventional laser welding apparatus, it is necessary to provide two rollers, that is, a pressure roller and a magnet roller, and a pressure roller elevating device or a magnet roller elevating device that moves each of the rollers to a desired vertical position, respectively. Since it is necessary to support it, the laser welding apparatus becomes large and equipment costs increase.

  By the way, there is a situation in which the welded portion of the member to be welded cannot be pressed with a roller or a pin. For example, when the welded portions of two members to be welded are bent in an L shape and confronted with each other, it is necessary to perform laser welding in a state where the tips of the two welded portions opposed to each other are free ends. Is done.

  In this case, since laser welding is a welding method with very high energy density, it has the characteristics that the penetration width is narrow and the penetration depth is deep, and the solidification rate is fast, so that both welded parts facing each other are It becomes extremely difficult to control the gap between the two at a constant temperature due to the heat during welding, and the welded portion becomes incomplete, and in some cases, laser welding cannot be performed.

  Therefore, the present invention provides a laser welding apparatus and a gap control method at the time of laser welding in which a simple structure is used to accurately control a gap between both welded portions so that laser welding can be reliably performed. .

  The present invention confronts the welded portion of the first welded member with the welded portion of the second welded member, and irradiates the laser from the higher-rigidity member side of the first and second welded members. A laser welding apparatus for welding, in which either one of a first welded member or a second welded member is excited to attract the other welded portion, and the gap between the two welded portions is kept substantially constant. The most important feature is the provision of excitation means.

  According to the present invention, when both welded parts are deformed in the direction away from each other due to residual stress or the like due to heat application during laser welding, by exciting one welded part by the excitation means and attracting the other welded part, Since the gap between the two welded portions can be maintained substantially constant, laser welding can be reliably performed by accurately controlling the gap between the two welded portions with a simple structure in which excitation means is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 3 show an embodiment of a laser welding apparatus according to the present invention, FIG. 1 is a perspective view of the laser welding apparatus, FIG. 2 is an enlarged sectional view of the excitation means, and FIG. 3 is a state in which the excitation means is operated. It is a side view of a laser welding apparatus.

  As shown in FIG. 1, the laser welding apparatus 1 according to the present embodiment includes a floor panel 20 of an automobile, and the inside of a side sill that extends in the vehicle front-rear direction on both sides of the floor panel 20 in the vehicle width direction and forms a vehicle body skeleton. This is an example in which the welding technique of the present invention is applied to a joint portion with the formed silicon inner 10.

  That is, in the present embodiment, the welded portion 11 of the sill inner 10 as the first welded member and the welded portion 21 of the floor panel 20 as the second welded member face each other, and both the welded portions 11 and 21 are opposed to each other. Are welded using a laser welding apparatus 1.

  The sill inner 10 is formed in a U-shaped cross section, and a sill outer (not shown) is also formed in an inverted U-shaped cross section, and the side sill having a closed cross section is configured by connecting both ends of the sill inner 10 and the sill outer. The

  The floor panel 20 is raised on both sides in the vehicle width direction to form the welded portion 21, and the welded portion 21 is joined to the side surface in the vehicle interior that becomes the welded portion 11 of the sill inner 10.

  In this embodiment, the material of the sil-inner 10 is SP783-590 (alloyed hot dip galvanized steel plate, 590 MPa class high tensile steel), and the material of the floor panel 20 is SP781 (alloyed hot dip galvanized steel plate). The thickness of the sill inner 10 is 1.4 mm, the thickness of the floor panel 20 is 1.0 mm, the sill inner 10 is formed thicker than the floor panel 20, and the rigidity of the sill inner 10 is increased. It is higher than the rigidity of the floor panel 20.

  The lower wall 12 of the sill inner 10 and the floor surface 22 of the floor panel 20 are placed on the base 30 when laser welding is performed, but are positioned on the lower side wall 12 of the sill inner 10 where the placement surface becomes narrower. A hole 12a is formed, the positioning hole 12a is inserted into a locating pin 31 protruding from the base 30, and the sill inner 10 is positioned and held by the locating pin 31.

  As shown in FIG. 1, the laser welding apparatus 1 includes a laser welding head 2 that emits a laser beam R. The laser welding head 2 includes an oscillator that oscillates a laser and a laser that is oscillated by the oscillator. And an optical system for collecting the light.

  The laser welding head 2 is arranged at a predetermined interval on the side of the sill inner 10 of the welded portions 11 and 21 facing each other, and laser light R oscillated from the laser welding head 2 is welded to the sill inner 10. Irradiation is performed along the welding line L of the portion 11. It is difficult to arrange the laser welding head 2 on the floor panel 20 side because interference between the floor panel 20 and the laser welding apparatus 1 occurs.

  Here, in the present embodiment, so-called laser / arc hybrid welding in which laser welding (YAG laser) and arc welding are combined. That is, in the laser welding head 2, a hybrid welding head 4 is configured together with an arc torch 3 that blows the arc A, and the hybrid welding head 4 enables laser-arc hybrid welding.

  A welding wire 5 is provided at the tip of the arc torch 3, and the aim position of the arc A to which the tip of the welding wire 5 is directed is the rear of the irradiation point of the laser light R in the welding direction (1 About 3 mm).

At this time, a YAG laser (output 3 kW) is used for the laser welding, and MIG welding is used for the arc welding. The conditions are a DC pulse with a current value of 140 A and a voltage value of 18 V, and a shielding gas (CO ₍₂ 10% + Ar 90%) is 20 liters / min.

  Moreover, in this embodiment, the welding part 11 of the sil inner 10 which becomes one welding part is excited to the said siliner 10, and the welding part 21 of the floor panel 20 used as the other welding part is attracted, and both welding parts are attracted | sucked. Excitation means 100 is provided to keep the gap δ between 11 and 21 substantially constant.

  Here, according to the gap control method during laser welding of the present embodiment, the welded portion 11 of the sill inner 10 and the welded portion 21 of the floor panel 20 facing the welded portion 11 are laser welded (in this embodiment, laser welding). In the lap welding by arc hybrid welding), the welding portion 11 of the sill inner 10 is excited, the attraction force of the other welding portion 21 by the magnetic force, and the deformation force of the other welding portion 21 that is deformed by the radiant heat at the time of welding. Therefore, the gap δ between the welded portions 11 and 21 is controlled to a substantially predetermined amount (maximum 3 mm).

  In addition, the excitation means 100 is provided in the sill inner 10 that has higher rigidity among the sill inner 10 and the floor panel 20.

  Further, the exciting means 100 is constructed by incorporating an electromagnet 101 as shown in FIG. 2 in a locate pin 31 for positioning the sill inner 10 as a member to be welded on the exciting side.

  That is, the locate pin 31 is formed in a hollow cylindrical shape whose upper end is closed, and the electromagnet 101 in which the coil 101a is wound is accommodated in the hollow of the locate pin 31, and the coil 101a is supplied with an electric current input thereto. It is connected to a magnetic field generator 102 that controls the value.

  A plurality of the locating pins 31 are arranged at predetermined intervals along the lower wall 12 of the sill inner 10, and the magnetic field is welded to the sill inner 10 by applying current to the electromagnets 101 in the locating pins 31 and exciting them. A magnetic force that excites the portion 11 and attracts the other welded portion 21 to the welded portion 11 is generated.

  The magnetic field generator 102 changes the current value output to the electromagnet 101 in accordance with the size of the gap δ between the welded portions 11 and 21, and increases the current value as the gap δ increases to increase the excitation force. By increasing the value, the attractive force of the other welded portion 21 can be increased.

  In the present embodiment, as shown in FIG. 1, the gap δ between the welded portions 11 and 21 reaches a predetermined amount between the free ends of the welded portions 11 and 21 facing each other, that is, between the upper ends. In this case, a bent portion 23 is provided as a protruding portion that contacts each other.

  That is, the bent portion 23 is formed by bending the upper end portion of the welded portion 21 of the floor panel 20 in the direction of the welded portion 11 of the sill inner 10, and the protruding amount S of the bent portion 23 corresponds to the gap δ. The predetermined amount is set in advance.

  Therefore, as shown in FIG. 3, when the exciting means 100 is excited and the welded portion 21 of the floor panel 20 is attracted to the welded portion 11 of the sill inner 10, the welded portion 21 of the floor panel 20 becomes the welded portion of the sill inner 10. 11 to prevent further proximity and hold the gap δ at a predetermined amount.

  According to the laser welding apparatus 1 and the gap control method at the time of laser welding according to the present embodiment, the exciting means for exciting the welded portion 11 of the sill inner 10 and attracting the welded portion 21 of the floor panel 20 to the sill inner 10. 100 is provided so that the gap δ between the welded portions 11 and 21 is kept substantially constant, so that the welded portions 11 and 21 are deformed in a direction away from each other due to residual stress or the like due to heat application during laser welding. In this case, the exciting means 100 excites one welded portion 11 and attracts the other welded portion 21 so that the gap δ between the welded portions 11 and 21 can be maintained at a constant gap amount suitable for welding. Laser welding can be reliably performed by controlling the gap between the welded portions 11 and 21 with high accuracy by using a simple structure in which the means 100 is provided.

  In addition, since the exciting means 100 is provided on the high-stiffness of the sill inner 10 and the floor panel 20, the welded portion 21 attracted by the exciting force of the exciting means 100 is on the floor panel 20 side having low rigidity. Therefore, the control of the gap δ by the excitation means 100 can be performed effectively.

  Further, since the excitation means 100 is configured by incorporating the electromagnet 101 in the locate pin 31 for positioning the sil-inner 10, the excitation means 100 can be configured by effectively using the existing locate pin 31, so that the configuration is simplified. In addition, the entire apparatus can be reduced in size.

  Furthermore, a bent portion 23 obtained by bending the tip of the welded portion 21 is provided between the free ends of the welded portions 11 and 21 facing each other, and a gap δ between the welded portions 11 and 21 is provided. Since the bent portion 23 comes into contact with the mating welded portion 11 when the fixed amount is reached, the gap δ can always be kept constant when the exciting means 100 is excited and output from the magnetic field generator 102. Control of the drive current of the excitation means 100 becomes easy.

  Further, in the laser welding machine 1 of the present embodiment, the hybrid welding head 4 including the laser welding head 2 and the arc torch 3 is configured by combining laser welding with arc welding to form a hybrid. The margin of the gap δ between 11 and 21 can be increased, and the occurrence of blowholes can also be reduced in lap welding of galvanized steel sheets.

  For this reason, since strict management of the gap δ in lap welding is not necessary, practical application is facilitated, and a welding speed substantially equal to that of laser welding can be obtained, and the advantage of high efficiency of the laser welding method can be enjoyed. .

  The present invention is not limited to the above-described embodiment, and various other embodiments can be adopted without departing from the gist of the present invention.

It is a perspective view of the laser welding apparatus in one embodiment of the present invention. It is an expanded sectional view of the excitation means in one Embodiment of this invention. It is a side view of the laser welding apparatus of the state which act | operated the excitation means in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser welding apparatus 2 Laser welding head 3 Arc torch 4 Hybrid welding head 10 Sill inner (1st to-be-welded member)
11 Welded part 20 Floor panel (second welded member)
21 Welded part 23 Bent part (projection part)
31 Locating pin 100 Excitation means 101 Electromagnet δ Clearance

Claims (6)

Laser welding in which the welded portion of the first welded member and the welded portion of the second welded member are opposed to each other, and laser welding is performed by irradiating a laser from the higher rigidity member side of the first and second welded members. A device,
Exciting means for exciting one of the first welded member and the second welded member to attract the other welded portion and maintaining a substantially constant gap between the two welded portions is provided. Laser welding equipment. The laser welding apparatus according to claim 1,
The excitation means is provided on a member to be welded having higher rigidity of the first member to be welded or the second member to be welded. The laser welding apparatus according to claim 1 or 2,
The exciting means comprises an electromagnet built in a locate pin for positioning a member to be welded on the exciting side. The laser welding apparatus according to any one of claims 1 to 3,
A laser welding apparatus, characterized in that a protrusion is provided between the free ends of both welded portions facing each other when the gap between the two welded portions reaches a predetermined amount. The laser welding apparatus according to any one of claims 1 to 4,
Laser welding equipment characterized by hybridizing laser welding with arc welding. In the lap welding of the welded portion of the first welded member and the welded portion of the second welded member facing the welded portion by laser welding, either the first welded member or the second welded member Exciting the welded portion, the gap between the two welded portions is controlled to a substantially predetermined amount in consideration of the attractive force of the other welded portion by the magnetic force and the deformation force of the other welded portion that is deformed by radiant heat during welding. A gap control method during laser welding characterized by the above.

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