JP2001191191A - Working head for laser beam welding robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working head for laser beam welding having simple constitution capable of pressurizing a work with a constant load. SOLUTION: The base part 3 of the working head 1 is attached to the wrist 2 of an articulated robot. A moving body 4 is attached to the supporting plate 10 of the base part 3 so as to vertically and freely displace. A laser projector 5 and a pressurizing means 6 are attached to the moving body 4. A constant load spring means 7 attached to the lower end part of the supporting plate 10 is provided with a spiral spring 22, the tip end of the spiral spring 22 is attached to the moving body 4, and a constant spring load is exerted downward on the moving body 4. The pressurizing means 6 is provided with a roller 20. When welding work is performed copying the surface of works 13, 14 by the roller 20, although the moving body 4 is vertically moved, pressurizing spring force from the constant load spring means 7 is always constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining head for a laser welding robot which is attached to, for example, an articulated robot and welds two superposed works such as steel plates.

[0002]

2. Description of the Related Art A laser welding robot performs a welding operation by irradiating a laser to a welding position while pressing a superposed work. In order to press the work, for example, Japanese Patent Application Laid-Open No. 03-57580 discloses a method in which a roller is pressed against the work by a coil spring to perform welding while pressing the work.

Further, as another conventional technique, Japanese Utility Model Application Laid-Open No.
No. 80682, “Laser Welding Robot” and Japanese Patent Application Laid-Open No. 10-113783, “Laser Welding Method of Plated Steel Sheet” disclose a method of pressing a steel ball with a cylinder.

[0004]

Problems to be Solved by the Invention
According to the method disclosed in Japanese Patent No. 580, when welding is performed following the surface of a work, the roller moves up and down due to the shape of the work, elastic deformation of the work, and the like. At this time, the roller presses the work by the spring load of the coil spring, but the coil spring increases the spring load in proportion to the amount of extension. Therefore, in this method, the pressing force fluctuates due to the vertical movement of the roller, thereby causing a problem that the welding quality is reduced.

Further, the method of pressing a steel ball with a cylinder has a problem that the cylinder itself is large and the configuration of a machining head is large. There is also a problem that the piping is cumbersome and valve control is required.

An object of the present invention is to provide a processing head for a laser welding robot capable of applying a constant pressing force to a work with a simple structure.

[0007]

According to a first aspect of the present invention, there is provided a machining head for a laser welding robot which is mounted on a wrist of a robot and irradiates a laser to a welding position of a superposed workpiece to perform laser welding. A base mounted on the wrist of the robot, a moving body provided to be vertically movable with respect to the base, a laser projector fixed to the moving body and irradiating laser light to a work below, and fixed to the moving body. A pressing means that presses the workpiece by contacting the workpiece from above in the vicinity of the welding position, and is interposed between the moving body and the base, and is disposed below the moving body from the base regardless of the vertical position of the moving body with respect to the base. And a constant load spring means for applying a constant spring load to the laser welding robot.

According to the present invention, a moving body is mounted on a base fixed to the wrist of the robot so as to be vertically displaceable, and a laser projector and pressing means are fixed to the moving body to form a processing head. The welding operation is performed by moving a processing head along a welding line of a workpiece by a robot. At this time, for example, the pressing unit having a roller moves along the welding line to press the work near the welding position, and irradiates the welding position with laser light from the laser projector to perform welding.

A constant load spring means for applying a constant spring load is interposed between the moving body and the base, regardless of the vertical position of the moving body with respect to the base. Therefore, when the work is pressed from above by the pressing means to perform the welding work following the work surface, the spring load by the constant load spring means is kept constant even if the moving body moves up and down. Thereby, the pressing force of the workpiece at the time of welding can always be kept constant.

In addition, since the laser projector and the pressing means are fixed to the movable body and move up and down integrally with the base, it is possible to prevent the laser projector from being out of focus due to the vertical movement of the movable body.

According to a second aspect of the present invention, the constant load spring means has a spiral spring.

According to the present invention, by forming the constant load spring means by a spiral spring, a constant spring load can be stably applied to the work.

[0013]

FIG. 1 is a perspective view showing a working state of a working head 1 for a laser welding robot according to one embodiment of the present invention. The laser welding robot is constituted by attaching a processing head 1 to a wrist 2 of a 6-axis vertical articulated robot, for example, and two works 13 and 1 made of a steel plate, for example.
4 is welded.

The processing head 1 has a base 3, a moving body 4, a laser projector 5, a pressing means 6, and a constant load spring means 7. The base 3 is fixed to the wrist 2 of the robot, and the support plate 1
Has zero. The support plate 10 is held so as to be substantially vertical during the welding operation.

The support plate 10 has a pair of left and right linear guides 11 and 12 extending vertically.
The plate-shaped moving body 4 is supported by the support plates 10 so as to be vertically displaceable.

The pressing means has a roller supporting member 21 attached to the lower end of the moving body 4 and a disk-shaped roller 20 rotatably supported by the roller supporting member 21. The work 13 and 14 are pressed near the welding position. In this embodiment, the laser projector 5 is a YAG (yttriu
m aluminum garnet) laser, which is fixed downward to the moving body 4 above the pressing means 6.

The constant load spring means 7 has a spiral spring 22, which is held at the lower end of the support plate 10,
The tip of the spiral spring 22 is fixed to the lower end of the moving body 4,
The moving body 4 is spring-biased downward with respect to the base 3.

FIG. 2 is a partial sectional view of the processing head 1, and FIG. 3 is a front view. The works 13 and 14 extend in a direction perpendicular to the paper surface of FIG. 2, and the work 14 is superimposed on the work 13, and the periphery of the work 14 becomes a welding line. Therefore, the workpieces 13 and 14 are joined by performing laser welding along the welding line following the workpiece surface.

In the welding operation, the focal point of the laser beam is set so as to be located at the welding position or in the vicinity of the welding position,
The roller 20 is rolled along the welding line on the work 14 near the welding position, and the welding operation is performed while pressing the work 14 against the work 13.

As shown in FIG. 2, the roller 20 is provided to be vertically adjustable with respect to the moving body 4 by bolts 30 of a roller support member 21. Therefore, by adjusting the vertical position of the roller 20 with the bolt 30, the laser projector 5 and the roller 2 are adjusted.
The vertical position relative to zero can be adjusted, and the focal point of the laser can be adjusted to an optimum position. Also, during welding work, the laser projector 5 and the pressing means 6 move integrally with the moving body 4 in the vertical direction, so that even if the moving body 4 moves up and down at the time of welding, the focus of the set laser is shifted from the welding position. Vertical displacement is prevented.

As shown in FIG. 2, the roller 20 is arranged such that the surface of the roller 20 facing the laser beam is inclined along the narrowed laser beam. Therefore, the lower end portion of the roller 20 pressing the work can press a position very close to the welding position. When the height position of the roller 20 is adjusted upward, the stopper 31 is attached to the roller support member 21 so that the roller 20 does not come into contact with the laser beam.

As shown in FIG. 3, the roller support member 21 is moved in the front-rear direction (the left-right direction in FIG. 3, the right-hand direction in FIG. 2) so that the lower end of the roller 20 abutting on the work 14 does not shift in the direction along the welding line. It is attached to the moving body 4 by a bolt 32 so as to be adjustable in a direction perpendicular to the paper surface).

The constant load spring means 7 has a holder 35, a drum 36 and a spiral spring 22.
It is closely wound around the drum 36. The drum 36 is held by the holder 36 below the support plate 10 of the base 3 so as to be rotatable around a rotation axis L perpendicular to the plane of FIG. The tip of the spiral spring 22 is fixed to the lower end of the moving body 4, but the base end is not fixed to the drum. With such a configuration, the constant load spring means 7 can apply a constant spring load downward from the base 3 to the moving body 4.

FIG. 4 is a graph showing the relationship between the extension (rotation angle) of the spiral spring 22 of the coil spring and the constant load spring means 7 and the load (torque). Line A in FIG. 4 is a coil spring, and line B is a spiral spring.

As can be seen from this graph, in the coil spring, the load increases in proportion to the amount of elongation, but in the spiral spring, after a predetermined amount D is initially drawn, the load is constant regardless of the amount of elongation. is there.

As described above, during the welding operation, the rollers 2
When 0 moves along the work surface, the moving body 4 moves up and down. Therefore, the spiral spring 22 is pulled out and the machining head 1 is positioned by the robot in consideration of the vertical movement amount of the moving body 4 assumed during the welding operation. That is, when the roller 20 is in contact with the workpiece 14 and the moving body 4 is supported on the workpieces 13 and 14, a length obtained by adding the predetermined amount D to one half of the vertical movement amount assumed during the welding operation. The position of the base 3 of the processing head 1 is determined so that the spiral spring 22 is pulled out.

With this configuration, even when the moving body 4 moves up and down during welding along the work surface,
A constant spring load is always applied, and the roller 20 can press the work 14 downward with a constant pressing force.
Thereby, welding quality can be improved.

In this embodiment, the amount of vertical movement during welding is
It is about 30 mm and the spring load is about 200N. In addition, since the own weight from the moving body 4, the laser projector 5, and the pressing means 6 is about 100N, the pressing force is about 300N.

The laser welding robot according to the present embodiment performs, for example, a work of welding a frame and a roof of an automobile. In the present embodiment, the laser projector 5 is a YAG laser, but the present invention is not limited to this, and may be a gas laser such as a carbon dioxide laser or a semiconductor laser.
Further, in the present embodiment, the pressing means 6 is configured to use the roller 20, but the present invention is not limited to this, and may be configured to use a steel ball rotatably supported. In this embodiment, the robot is an articulated robot. However, the robot may be a rectangular coordinate robot or a cylindrical coordinate robot.

[0030]

As described above, according to the present invention, by using the constant load spring means, the work can always be pressed with a constant load even if the moving body moves up and down following the work surface. . Further, since no piston or the like is used, no piping or the like is required, and it is small and lightweight, and there is no need to control the pressing force.

Also, by using a spiral spring,
A constant and constant spring load can be applied.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a use state of a processing head 1 for laser welding of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a processing head 1 for laser welding.

FIG. 3 is a front view of the processing head 1 for laser welding.

FIG. 4 is a graph showing a relationship between elongation and load of a coil spring and a spiral spring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing head for laser welding 2 Wrist of robot 3 Base 4 Moving body 5 Laser projector 6 Pressing means 7 Constant load spring means 13, 14 Work 20 Roller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiichi Yagi 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside Akashi Plant (72) Inventor Shinji Koga 3-1-1 Higashi-Kawasaki-cho, Chuo-ku, Kobe-shi, Hyogo No. 1 Kawasaki Heavy Industries, Ltd.Kobe Plant (72) Inventor Toshifumi Matsumoto 3-1-1 Higashi Kawasaki-cho, Chuo-ku, Kobe City, Hyogo Prefecture Kawasaki Heavy Industries, Ltd.Kobe Plant (72) Inventor Masayuki Inuzuka Central Kobe City, Hyogo Prefecture 3-1-1 Higashi-Kawasaki-cho, Kobe Kawasaki Heavy Industries, Ltd. Kobe Factory (72) Inventor Takayuki Murata 3-1-1, Higashi-Kawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Kobe Factory (72) Inventor Nishio 3F 1-1 term, Higashi-Kawasaki-cho, Chuo-ku, Kobe, Hyogo Pref. CA14 CD15 CE06

Claims (2)

[Claims] 1. A laser welding robot machining head mounted on a wrist of a robot and irradiating a laser to a welding position of an overlapped workpiece to perform laser welding, a base attached to a wrist of the robot, A movable body movably provided in a vertical direction, a laser projector fixed to the movable body and irradiating a lower workpiece with laser light, and a workpiece fixed to the movable body and abutting from above on a vicinity of a welding position of the workpiece. Pressing means for pressing, a constant load spring means interposed between the moving body and the base, and applying a constant spring load downward from the base to the moving body regardless of the vertical position of the moving body with respect to the base. A processing head for a laser welding robot, comprising: 2. The processing head for a laser welding robot according to claim 1, wherein said constant load spring means has a spiral spring.