JP3109261B2 - Laser welding unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding unit used for spot welding of bodies such as automobiles.

[0002]

2. Description of the Related Art Conventional electric spot welding means (hereinafter referred to as "conventional example 1") is limited in terms of the thickness of a material to be welded to each other due to the limitation of power supply capacity. If one spot welding point is to be performed in close proximity to one welding point (spot welding point), the current of this spot welding is diverted to the already welded spot welding portion, and an effective spot welding is obtained. And the reliability of spot welding may be impaired. In particular, the above-mentioned conventional example 1
In this case, it is difficult to seam-weld the two materials to be joined into an arc-shaped curve. On the other hand, in the above-mentioned conventional example 1, since a large current must be instantaneously passed, a conductor having high flexibility must be used, and not only is safety and the life of the electrode chip disadvantageous, but also , Joining 2
A large pressing force is required in advance to sufficiently adhere the two materials to be joined together, and when the materials to be joined are thin plates, the metal mist and the like melted during welding often scatter in all directions, and the joining is performed. There is a possibility that the welding point of the part is substantially reduced and a depression is generated. Furthermore, the two-electrode tip used in the above-mentioned prior art example 1 must be always kept in a cleaned state in order to maintain the conductivity, the cooling property and the pressure resistance. On the other hand, although some laser spot welding means [hereinafter referred to as "conventional example 2"] have already been proposed, these methods use a laser beam that is obliquely applied to a material to be bonded when the material to be bonded is a thin plate. And weld to increase the welding length. However, in Conventional Example 2 described above, excessively rapid heating and rapid cooling by welding with a laser beam increase the amount of probe holes and impurities mixed in the metal structure between the non-welded portion and the welded portion, and An excessive hardness difference may occur, as if quenching of a metal material or local material distortion and cracking of a metal structure may occur . Therefore, a document as an improvement means of Conventional Examples 1 and 2 is Japanese Patent Laid-Open No. 2-25715 [hereinafter referred to as "Conventional Example 3"]. In FIG. 11, a laser beam from a laser device 1104 is focused on a joint 1109a of a material to be joined 1109 via a condenser lens optical system 1115 and reflectors 1122 and 1123 to perform laser welding. A swinging operating rod 1105 provided with a laser device 1104 at the top of a machine frame having a horizontal arm operating rod 1103
The pivotally mounted, the welded material 11 to one end 1103a of the horizontal arm Replace 1103
A lower chip 1108 for supporting 09 is provided.
An upper tip is attached to one end of the swinging rod 1105 located directly above 08.
1112 is provided integrally, and a condenser lens optical system 1115 fixed in the upper swinging rod 1105 of the upper chip 1112 is provided so as to irradiate the laser beam from the laser device 1104 downward. Reflectors 1122, 1123 that focus on the material to be joined 1109 on the lower swinging rod 1105 of the system 1115
This is a device in which a revolving member 1121 provided with is rotatably provided via a motor 1126, a small gear 1127, and a bearing 1118 .

[0003]

In the prior art 3, the work to be joined (work) is superposed by using a laser beam.
Although seam welding can be performed on the 1109 in an arc shape, the biggest decisive problem of the conventional example 3 is the method of fixing the work, that is, positioning because the workpiece 1109 is sandwiched by the swinging operating rod 1105. The accuracy is extremely poor. In addition, the turning hole 1121
Is exposed, and the cover member 11 covering the joint 1109a is exposed.
25 also has the disadvantage that it is not a complete protection against the dangers associated with laser beam welding. By the way, the laser light is invisible and has a very high energy density, so that the damage to the human body is increased. Particularly, the wavelength of the YAG laser light has a high risk to human eyes due to its wavelength. From these safety aspects,
The device using the laser beam also had a drawback that became large due to its safety device. There is a need for a device that compensates for this drawback and that is highly secure. further,
For example, a gap exists on the coupling surface of an automobile body due to accumulation of various errors. In order to ensure the quality of the welded portion in laser beam welding, it is important that the gap be crushed at the time of welding and the plate be kept in close contact. Here, the present invention has been studied in order to realize a welding unit having sufficient conditions, which completely replaces the above-mentioned necessary conditions and substitutes for the future spot welding, and as a first means,
The present invention was conceived in an effort to find a laser welding work unit that facilitates positioning of a tool, is extremely accurate, and is capable of continuous, automated, points, straight lines, circles, and arbitrary curves. Further, as a second means, even in the comparative example 3 which has been relatively advanced, the difficulties which have not yet been eliminated and the disadvantages related to the safety device are completely wiped out, and the improvement and new demands are sufficiently satisfied. In order to make it safe to completely shield the laser beam, it has wiped out all the drawbacks in electron beam welding, let alone the problems of the conventional spot arc welding means,
For example, an object of the present invention is to provide a laser welding unit that is also applied to spot welding of a body of an automobile or the like.

[0004] As means for solving the above-mentioned problems, the invention according to claim 1 is capable of moving to an arbitrary position by being driven by a movable body, and rotating the operating shaft for supporting the tool. A trajectory interpolator that operates so that the distance between the tool and the center of rotation of the operating axis, which is a fixed distance (r) away from the center of rotation of the shaft, is equal to the radius R (θ) of the circular motion performed by the tool. The interpolation device has a pair of clamp members for clamping and fixing the work by the work contact surface provided with the roller member, and irradiates a laser beam from a tool tip toward a welded portion shielded from surroundings. The workpiece gripped by the clamp member is welded, and after being positioned at a predetermined position by driving the movable body, circular or angular locus welding is performed in a shielded state. It is characterized in that the circular or angular locus welding can be repeated after moving the required distance by driving the moving body. According to the second aspect of the present invention, the movable member can be moved to an arbitrary position by being driven by the movable member, and can be moved at a predetermined distance (r) from the rotation center of the rotating shaft for rotating the operating shaft supporting the tool. A trajectory interpolator that operates so that the distance between the axis of rotation and the tool is equal to the radius R (θ) of the circular motion performed by the tool; the trajectory interpolator includes a workpiece contact surface provided with a roller member; A pair of clamp members for clamping and fixing the work by irradiating a laser beam from the tool tip toward a welded place shielded from the surroundings to weld the work held by the clamp member. In addition, after being positioned at a predetermined position by driving the movable body, semi-circular or half-angle trajectory welding is performed in a shielded state, and after moving the required distance by driving the movable body, the semi-circular Or tracking the trajectory obtained by inverting the half-angle shaped trajectory, but capable of performing its semicircular or repeated byte shaped trajectory welding, characterized in that.

[0005]

According to the present invention, the work is stably pressed by the above means, precise positioning is performed, and even a very small movement while being fixedly held is easily performed by a different trajectory interpolation device in conjunction with the movement of the robot. Therefore, it is possible to freely respond to a request for a deformed shape of a workpiece by laser welding, and automation can be performed. further,
Since the laser beam to be emitted is completely shut off from the outside at the welded portion, the personal security is also perfect. In addition, the work can be freely displaced by the movable body while pressing and holding the work by point contact, and accurate laser welding of figures such as continuous weaving can be performed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially cutaway side view of an embodiment of the present invention. In this embodiment, a member to be joined is vertically pressed and clamped by one upper clamp and the other lower clamp, and the joined portion is held inside a machining hole formed in a central portion of the upper clamp, This is a means for performing laser welding by irradiating laser light from above the clamp. That is,
This embodiment is a unit for performing a welding process within a movable range of a tool in a positioning state in which a member to be joined is pressed and clamped by upper and lower clamps. For example, an industrial robot is assumed as the movable body. The entire laser welding unit of the present invention is mounted on the robot flange 14 which is the tip of the arm of this industrial robot. In addition to the movement of the robot flange 14, a trajectory interpolation device 10 [Japanese Patent Laid-Open No. 63-235073] performs a trajectory movement along the welding line. The trajectory interpolating device 10 adjusts and controls the optical laser supplied from the optical fiber 6 for transmitting energy in the laser drive unit 1 so that a workpiece 11a,
The joint 12 of 11b is irradiated. The upper portion of the trajectory interpolation device 10 is covered with an upper lid 2a, the side surface of which is connected to a cylindrical cylindrical portion 2b, a lower conical portion 2c, and a cylindrical portion 2d, and the leading end portion reaches a pressing leading end portion 2e. Since the pressing portion 2e is repeatedly pressed, the tip portion 2e is formed of a hard member different from other integrally formed portions. An elastic body 5 is provided on a part of the cylindrical portion 2b.
Absorbs the vertical blur at the time of positioning through the through hole to improve the deviation of the optical axis due to the impact. The support portion 5a and the connecting portion 1a are screwed, and the trajectory interpolation device 10 is held by the upper clamp 2. ing. Laser weld 12 at the joint of workpieces 11a and 11b
As a means for supporting the air cylinder 7 from below, a joint 8a, which is disposed at the tip of a cylinder 7a, which is a movable portion of an air cylinder 7 having one side screwed to the cylindrical portion 2b of the upper clamp 2,
8b, a lower clamp 3 comprising a support arm 3a and a support tip 3b is provided. When the cylinder 7a is raised, the gap between the upper clamp 2 and the lower clamp 3 is reduced. Further, a side plate 7a is screwed on the other side surface of the air cylinder 7, and on the side plate 7a, an equilibrium mounting member 9 for holding the tool 4 in a floating state following a work which is a usual means.
a and the equilibrium mounting member 9b are fixed, and a joint 13a is provided therebetween.
A joint 13b, which is an orthogonal axis, is rotatably connected to a substantially central portion of the joint 13a via a sleeve bearing 13c, and the outer peripheral surface of the joint 13b and the equilibrium mounting members 9a, 9b are provided. Springs 9c, 9d
Is arranged. With such a configuration, first, the robot flange 14 is positioned by the industrial robot [movable body], the cylinder 7a of the air cylinder 7 is lowered, and the joint 12 between the workpieces 11a and 11b to be welded is clamped by the upper clamp 2. The cylinder 7a starts to rise in a state in which it is brought into contact with the presser tip 2e, and the support tip 3b presses down on the presser tip 2e with the joining portion 12 biting. With the robot flange 14 fixed, high-quality welding can be performed while the robot flange 14 is fixed by operating the trajectory interpolating device 10 and irradiating the laser beam from the tool 4 with a line. Is performed. By the way, the cylindrical portion 2b, the conical portion 2c below it, and the cylindrical portion 2d do not necessarily have to have a basic shape of a circular shape. However, the same function and effect of the present invention can be obtained. Further, it is also possible to provide a means which enables continuous long welding lines to be welded while linking the moving operation of the movable body . In other words, the means is such that a ball roller or the like is disposed on each of the opposing surfaces of the tip 11e and the support tip 3b for the workpieces 11a and 11b, and the robots 11a and 11b are pressed and gripped by point contact with the robot flange 14b. With this operation, all the units including the tool 4 are slid and positioned at the next welding point, and the next welding is performed by operating the trajectory interpolation device 10 [means for sliding all the units will be described later]. . FIG. 2 is a cross-sectional view taken along the line AA of FIG. The same reference numerals in the drawings denote the same or corresponding parts. Various shapes can be considered for the opening of the presser tip 2e, if necessary. The area of the opening is the movable range of the tool 4 by the operation of the trajectory interpolating device 10. For example, FIG.
(a) is suitable for elliptical or linear locus welding, and FIG. 2 (b) is suitable for circular or widening locus welding.

According to this embodiment, the following effects can be obtained. That is, since the diameter of the laser beam assumed in the laser welding is small [1 mmφ or less], the laser beam must be moved in order to obtain the required strength at the welding location. Moreover, the trajectory interpolation device is applied as a means for realizing various trajectories such as linear movement, circumferential movement, polygonal movement, etc., depending on the location and the shape of the joint portion, and the movement of the movable body is smoothly performed to continuously construct the welding line. On the other hand, the laser beam is invisible, and the energy density is very high, so that the human body is greatly damaged. The risk is high. From the viewpoint of safety, a device using laser light has the disadvantage that it must be scaled up to add the safety device, and a device that is extremely safe while compensating for this disadvantage completely is required. However, for example, since there is a gap in the joint surface of the automobile body due to accumulation of various errors, in order to ensure welding quality, this gap should be crushed at the time of welding, and the steel sheet forming the body should be closely adhered. It is important to take into account all the above requirements, that is, the upper clamp 2 has a cylindrical shape or an elliptical cylindrical shape or an elliptical cylindrical shape as required, and is generated inside after the member to be joined is clamped. Laser light is completely shielded. The whole mechanism such as the cylinder 7a for clamping the member to be welded and the air cylinder 7 for driving the member is floated from the robot flange 14, and when the member to be welded is clamped, one of the whole units is automatically adjusted as a float mechanism. The movement of the clamp is lightened. Further, the inside of the support tip 3b of the lower clamp 3 is hollow, and a trajectory interpolation device 10 (not shown) is housed therein, and the positions of the lower clamp 3 and the trajectory interpolation device 10 are fixed, so that the The height from the surface of the member to be joined to the laser nozzle of the tool 4 is mechanically kept constant. Furthermore, the central portions of the upper clamp 2 and the lower clamp 3 which are opposed to each other have a depression, and even if the member to be joined is melted by the laser light, the laser light does not leak to the outside. Moreover, since the trajectory interpolation device 10 is attached via the elastic body 5 such as an anti-vibration rubber to avoid an impact when clamping the member to be joined, the service life becomes long and the positioning adjustment becomes accurate. . The important "stand-off, which is the distance from the surface of the member to be joined to the laser nozzle of the tool 4" is mechanically constant during laser beam welding, and a stable welding state can be realized without a sensor. In this way, the parts having different plate thicknesses of the members to be joined can be dealt with by exchanging the tip of the holding tip 2e and setting the dimensions of the standoff. In addition, the thickness variation of the members to be joined is generally 0.8 to 1.0 mm.
The thickness is 0.1 mm or less, and there is no problem because the thickness easily falls within the range of 1 mm ± 0.5 mm of the stand-off dimension required for laser beam welding.

FIG. 3 shows a configuration diagram of another embodiment of the present invention. 3A is a side view, and FIG. 3B is a half of a front sectional view taken along line BB of FIG. 3A. In this other embodiment, after the material to be joined is pressed and clamped between the left clamp and the right clamp, the joint portion of the material to be joined is completely held inside both clamps, and the laser is applied from above the central portion of both clamps. This is a means for performing welding by irradiating light, and this is the second invention of the present invention. Robot arm 14a of industrial robot [movable body]
Clamp fixing part 16 is attached to robot flange 14 attached to
Is screwed. Trajectory interpolation device 10 according to another embodiment
Is provided with a guide (for example, a ball guide or the like) 20 slidable to the left and right at an intermediate portion, and provided with one clamp-moving portion 15 in the form of a grasping hand that enables parallel movement thereof, and The other clamp fixing portion 16 in the shape of a grasping hand is provided facing the portion 15. The trajectory interpolation device 10 is attached to the upper portion of the rotation fixing portion 17 of the clamp fixing portion 16 via the elastic body 5, further via the support portion 5a and the connecting portion 1a. A flat cover 21 having a size that can sufficiently block the laser light emitted from the trajectory interpolation device 10 is fixed to the side portions on both sides of the clamp fixing portion 16. Clamp tip (moving part) 15
a and a clamp tip (fixing portion) 16a are screwed to the clamp moving portion 15 and the clamp fixing portion 16, respectively. The clamp tip (moving part) 15a rotates the clamp tip rotation pin 19 to slightly move the tip, absorbs manufacturing errors (prevents deviation), and enhances the adhesion during clamping. This allows the workpieces 11a and 11b to be rubbed together. The adjustment range is the width of the gap between the clamp tip rotating sine stopper 18 and the clamp tip (moving portion) 15a. At the respective terminals on the lower side of the clamp fixing part 16 and the clamp moving part 15, the tips of both terminals are formed so as to be engaged with each other so that the works 11a and 11b can be clamped and fixed. Sliding means are provided on the gripping contact surfaces of the workpieces 11a and 11b of the clamp tip (moving portion) 15a and the clamp tip (fixed portion) 16a. In other embodiments, welding between the end faces of the workpiece can be performed.

FIG. 4 is a structural view of another embodiment of the present invention. FIG. 4 (a) is a side view, and FIG. 4 (b) is a front sectional view taken along line CC of FIG. 4 (a). Represents half. This alternative embodiment is illustrated in FIG.
FIG. 4 is a modification of the other embodiment, and FIG. 4 has approximately the same operation as that of FIG. 3, but the work is more firmly pressed against the work compared with the other embodiment of FIG. There is an effect that welding can be performed in a state where the welding is performed. The fixed side of the driving unit 7 is rotatably mounted on the support 16a via a rotatable support 16a near the terminal on the upper side of the clamp fixing unit 16. The cylinder 7a, which is the moving side of the driving unit 7, is connected near the terminal of the cylinder 7a, and the cylinder 7a and the clamp moving unit 15 are rotatably connected about the axis thereof at the connecting portion 15a.
The clamp moving unit 15 is rotated left and right about the axis of the rotation coupling unit 17. In the same manner as in FIG. 3, at the respective terminals on the lower side of the clamp fixing part 16 and the clamp moving part 15, the tips of both terminals are formed so as to be engaged with each other so that the works 11a and 11b can be clamped and fixed. ing.
3 and 4, when the robot arm 14a of the industrial robot is positioned at a predetermined position, the cylinder 7a shifts from left to right, and the clamp fixing portion 16 is moved. The workpiece 11a, 11b is brought between them and the cylinder 7a shifts from right to left in reverse, and the clamp fixing part
The workpieces 11a and 11b are clamped between the clamp moving section 16 and the workpiece to fix the workpieces without distortion.
While moving the locus along the shape of the welded portion 12 of the workpieces 11a and 11b, a laser beam is irradiated from the tip of the tool to weld the laser welding line 12 of the workpieces 11a and 11b. by the way,
Although the states shown in FIGS. 3 and 4 seem to be applied to linear locus welding, curved locus welding is possible even when the workpieces 11a and 11b are gripped.

The present invention makes it possible to automatically trace a unique trajectory . FIG. 5D shows one such means. That is, the robot flange 14 attached to the robot arm 14a of the industrial robot [movable body]
The laser welding is performed in the trajectory interpolating device 10 in the clockwise direction along the small circle 51 after the positioning is performed in the vicinity of the center 50 of the welding portions a and 11b. After that, the robot arm 14a of the industrial robot [movable body] is horizontally moved to perform parallel positioning by the distance l to perform positioning, and furthermore, the trajectory interpolating device 10 is moved clockwise along the small circle 52. Laser welding is repeated on the small circle 53
Laser welding is performed as indicated by the arrow in the traveling direction. Here, the circumferential locus has been described as the small circle 51. However, the same applies to the elliptical locus, and the laser welding of an arbitrary shape can be similarly performed for the circular locus instead of the circular locus. It is clear.

FIG. 6 shows another means for tracking the welding locus of the present invention .
Shown in In FIG. 6 (a), an industrial robot [movable body]
Robot flange 14 attached to robot arm 14a
Is positioned approximately 60 near the center of the welding location of the workpieces 11a and 11b, and then the trajectory is traced along a small circle by the
The welding is performed while emitting laser light while performing the above. When the welding is completed, the robot arm 14a is moved to perform parallel positioning by a distance l to perform positioning, and the clockwise semicircular locus is reversed, and While the trajectory is being traced along the small circle in the direction by the trajectory interpolation device 10, welding is performed while emitting laser light, and when that is completed, the robot is moved in parallel by a distance l for the next welding, and positioning is performed by the robot. This operation is performed by the positioning movement of the flange 14, and such operations are sequentially repeated, so that continuous welding of small circles and semicircles is performed. FIG. 6 (b) is a detailed view of the semicircular movement, in which the trajectory interpolator 10 performs dummy linear movement from the origin 60, and then performs the semicircular trajectory movement of the welding active movement in the clockwise direction by the trajectory interpolator 10. The following semicircular movement 61a does not move, but is analyzed by parallel movement and positioning by the robot arm 14a by a distance 1 via a pressure contacting / holding member employing a tool moving means [FIG. 7] described later. is there. In the welding method shown in FIG. 6A, the welding bead can be thickened by welding wiving, the welding pitch can be reduced, and the welding strength can be increased. Fig. 6 (a),
(b) is described for the semi-circular locus motion, but is also effective for the semi-elliptical locus motion shown in FIG. 5 (b), and is also effective for a semi-circular but not semi-circular locus motion.

FIG. 7 is a partial plan view for describing the tool moving means abbreviated earlier. For example, as shown in the drawing, a ball roller 2f is formed in the contact surface of the pressing tip 2e of the upper clamp 2 in FIG. As far as possible, the projecting spherical surface of the ball roller 2f is in contact with the contact surfaces of the workpieces 11a and 11b. This means is similarly arranged on the supporting tip 3b of the lower clamp 3. Since the contact surfaces of the workpieces 11a and 11b are vertically pressed and gripped by the protruding spherical surfaces of the ball rollers 2f, the positioning is easily performed by the point contact pressure of the ball rollers 2f, and the parallel movement by the distance l is performed. The operation performed by the movement of the robot arm 14a is as described above. It is clear that this means is also possible in the embodiments of FIGS. 3 and 4 [the second and third inventions of the present invention].
Although there is no problem in the embodiment shown in FIGS. 3 and 4, the means for arranging the ball roller 2f on the welding bead as shown in FIG.
The ball of the ball roller 2f passing through the bead surface on the welding surface of a, 11b, for example, two balls on the welding line 12 in FIG. 7, may be extracted and omitted.

The trajectory interpolation device 10 employed in these embodiments is described in detail in the previously disclosed document [Japanese Patent Laid-Open No. 63-235073], and will be described in general. FIG. 8 is a side sectional view of one embodiment of the trajectory interpolation device, and FIG.
(a), (b) It is the front view and rear view. A T1 axis motor 1031 and a T2 axis motor 1032 for rotating the T1 axis 1036 are mounted side by side at the rear end of the case 1030. The T1 axis motor 1031 rotates the T1 axis 1036 by the gear 1033,
Both shaft 1036 and T2 shaft 1034 are cylindrical,
The T2 shaft 1034 is inserted into the T1 shaft 1036 via the.
Therefore, the T1 axis 1036 and the T2 axis 1034 have a concentric structure. Further, a constant velocity coupling [Oldham coupling] 1039 is provided at an intermediate portion of the T2 shaft 1034 drive transmission system, and the illustration of the laser drive unit 1 is omitted. In such a structure, a certain distance from the rotation center 1013 of the rotation axis T1 for rotating the operation axis T2 for supporting the tool 4
(r) The rotation center 1014 of the distant operation axis T2 axis and the tool 4
Is operated so that the distance from the tool 4 becomes equal to the radius R (θ) of the circular motion performed by the tool 4, and given the information of the peripheral speed, radius, and long side of the tool 4, the start point is set. The trajectory interpolation device 10 directly controls the tool 4 independently of the movement of the robot, and controls the tool 4 to perform a circular motion such as a circle or an ellipse or a square motion such as a square, a rectangle, or a polygon. Let it do. This embodiment has an advantage that the entire trajectory interpolation device 10 can be formed very compact. That is, as shown in FIGS. 5A and 5B, the rotation center 1013 of the rotation axis T1 is positioned at the origin C, and the tool 4 is set at the start point S at the center of the side A.
The speed of the drive motors of both axes is determined from the proportional constant and the welding speed, and the function of the gear ratio between the rotation axis T1 axis and the operating axis T2 axis is determined by the tool 4 at the X and Y coordinates shown in FIG. The coordinate values (X1, Y1) are as follows: X1 = rcos θ1 + rcos θ2 Y1 = rsin θ1 + rsinθ2 Since the start point S is taught, the moving angle θ02 of the movement axis T2 axis at each time is the date of the side B The calculation is as follows: B = R (θ) = r · (1/2) ^1/2 · (1−cos θ02) ^{1/2 From} these, the positions around FIG. 5 (a) and FIG. Calculation becomes possible, and the welding point of the tool 4 can always be controlled.

FIG. 10 is a side sectional view of another embodiment of the trajectory interpolation device. Regarding the opening of a small hole, the gear 1042 meshes with the tip of the T1 shaft 1036,
An arm 1043 is fixed to the gear 1042 by a bolt, and the tool 4 is supported on the arm 1043 via a bearing 1044. When the T2 axis motor 1032 is driven, the arm 1043 rotates via the gear 1042, thereby Since the tool 4 rotates by an angle θ about the T2 axis rotation center 1014, the rotation of the angle θ causes the tool 4 to move by the radius R (θ) of the small hole from the T1 axis rotation center 1013, thereby opening the small hole. The same applies to the case of the locus figure. This is advantageous in that the constant velocity coupling [Oldham coupling] 1039 shown in FIG. 9 is not necessary, and the constant distance r and the radius R (θ) of the circular motion can be increased.

[0015]

As described above, according to the present invention, it is possible to position a tool which is installed inside a laser beam irradiated part completely shielded and presses and clamps a member to be joined and emits a laser beam. It is extremely accurate and easy, and various figure welding is possible while pressing and holding the members to be joined.
Furthermore, by arranging means for pressing and holding the welding bead by point contact on the clamp portion of the member to be welded, once the positioning clamp is performed at the welding start point of the member to be welded, movement of the tool by the movable body is prevented. Since automatic movement control can be performed continuously while pressing and holding the workpieces, it is possible to obtain an ideal laser welding unit for spot welding of workpieces of all shapes, small figure welding, continuous welding in any shape, etc. A special effect can be achieved.

[Brief description of the drawings]

FIG. 1 is a side view showing a partially cut-out configuration in an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a side view and a partial cross-sectional view illustrating a configuration according to another embodiment of the present invention.

FIG. 4 is a side view and a partial cross-sectional view illustrating a configuration according to another embodiment of the present invention.

FIG. 5 is an explanatory view of a procedure of one welding line applied to the embodiment of the present invention.

FIG. 6 is an explanatory view of a procedure of another welding line applied to the embodiment of the present invention.

FIG. 7 is a partial plan view for explaining a tool moving means while pressing and gripping a workpiece to be welded employed in an embodiment of the present invention.

FIG. 8 is a side sectional view of a trajectory interpolation device applied to the embodiment of the present invention.

FIG. 9 is a front view and a rear view of the trajectory interpolation device.

FIG. 10 is a side sectional view of another trajectory interpolation device applied to the embodiment of the present invention.

FIG. 11 is a side sectional view showing a configuration of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser drive unit 1a Connecting part 2 Upper clamp 2a Upper lid 2b Cylindrical part 2c Conical part 2d Cylindrical part 2e Holding tip part 2f Ball roller 3 Lower clamp 3a Support arm part 4 Tool 5 Elastic body 5a Support part 6 Optical fiber 7 Air cylinder 7a Cylinder 8a Joint 8b Joint 9a Equilibrium mounting member 9b Equilibrium mounting member 9c Spring 9d Spring 10 Trajectory interpolator 11a Work 11b Work 12 Laser weld 13a Joint 13b Joint 13c Sleeve bearing 14 Robot flange 14a Robot arm 15 Clamp moving part 15a Clamp tip Part (moving part) 16 Clamp fixing part 16a Clamp tip part (fixing part) 17 Rotation joint part 18 Clamp tip rotation limit stopper 19 Clamp tip rotation pin 20 Guide

Continuation of the front page (56) References JP-A-60-234787 (JP, A) JP-A-62-235073 (JP, A) JP-A-4-39584 (JP, U) JP-A-1-60792 (JP , U) Fully open sho 63-62291 (JP, U) Fully open sho 60-38686 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26/00 B23K 26/08 B25J 9/10

Claims (2)

(57) [Claims] An operating shaft rotation center which can be moved to an arbitrary position by being driven by a movable body, and which is separated by a predetermined distance (r) from a rotation center of a rotating shaft for rotating an operating shaft supporting a tool. A trajectory interpolator that operates so that the distance between the tool and the tool is equal to the radius R (θ) of the circular motion performed by the tool. It has a pair of clamp members for clamping and fixing, and irradiates a laser beam from the tip of the tool toward a welded portion shielded from the surroundings, thereby welding the work held by the clamp member, and ,
After being positioned at a predetermined position by driving the movable body, circular or angular locus welding is performed in a shielded state, and after moving the required distance by driving the movable body, the circular or angular locus welding is performed. A laser welding unit capable of performing repetition. 2. An operating shaft rotation center which is driven by a movable body and can be moved to an arbitrary position, and which is separated by a predetermined distance (r) from a rotation center of a rotation shaft for rotating an operation shaft supporting a tool. A trajectory interpolator that operates so that the distance between the tool and the tool is equal to the radius R (θ) of the circular motion performed by the tool. It has a pair of clamp members for clamping and fixing, and irradiates a laser beam from the tip of the tool toward a welded portion shielded from the surroundings, thereby welding the work held by the clamp member, and ,
After being positioned at a predetermined position by driving the movable body, semi-circular or half-angle trajectory welding is performed in a shielded state, and after moving the required distance by driving the movable body, the semi-circular or half-angle trajectory is welded. A laser welding unit capable of tracking a trajectory obtained by inverting the trajectory and repeating welding of the semicircular or half angle trajectory.