JPH10244376A - Seam welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a versatile seam welding equipment that is capable of quick setup change in the seam welding of various kinds of fuel tank and that can be manufactured at low cost. SOLUTION: A work 1 is carried in, welded, and carried out by attaching to a robot arm 7 a handling jig which is formed in accordance with the shape of the work 1 and which clamps and unclamps the work 1, and transferring the handling jig, by turning the robot arm 7, to each equipment for carrying-in 2, carrying-out 3, and seam welding 4. The handling jig is prepared in plural kinds for each work 1 different in shape; the jig corresponding to a supplied work is attached to the tip end of the robot arm 7; the remaining jigs are temporarily placed on a temporary placement base 33; and, at the time of change in the kinds of work, the jig currently in use is automatically exchanged with the jig supported on the temporary placement base 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seam welding apparatus for seam welding a work using a robot.

[0002]

2. Description of the Related Art A fuel tank comprises an upper half and a lower half formed by a sheet metal press. In this fuel tank, the upper half and the lower half are overlapped, and the overlapping peripheral flanges are temporarily fixed at a plurality of spots by spot welding.
The peripheral flange of the integrated fuel tank thus formed is sandwiched between a pair of upper and lower electrode wheels of a seam welding machine. It is produced by doing.

Conventionally, a vertically fixed fuel tank temporarily fixed is set on a dedicated jig, and then the tank is rotated while being guided by a copying jig having a shape corresponding to the planar shape of the fuel tank. The entire periphery is seam-welded.

[0004]

In a conventional seam welding apparatus, a dedicated jig and a copying jig are required for each type of fuel tank. Therefore, each time the shape of the fuel tank is changed, these jigs are replaced. It has to be newly manufactured and replaced, which requires a great deal of labor and time when changing the model, which has led to an increase in cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a versatile seam welding apparatus which can be efficiently changed even when seams are welded to various kinds of fuel tanks and can be manufactured at low cost. .

[0006]

In order to achieve the above object,
The device of the present invention is capable of supporting loading and unloading devices arranged in parallel, a handling jig formed to correspond to the shape of the work and clamping and unclamping the work, a seam welding machine, and a handling jig. A temporary receiving stand, the handling jig is detachably attached to the tip portion, and comprises a loading device, an unloading device, a seam welding machine and a robot arm for transferring the handling jig to the temporary receiving stand while turning, Prepare multiple types of handling jigs for each workpiece with different shapes, attach the handling jig corresponding to the supplied workpiece to the end of the robot arm, and temporarily place the remaining handling jigs on the temporary mounting table, A seam welding system that automatically replaces the currently used handling jig with the handling jig supported by the temporary table when switching Apparatus.

[0007] The apparatus of the present invention has the following features: The work is transferred to a carry-in position, a welding position, and a carry-out position, and a control is performed at the welding position to eliminate a deviation between a scheduled welding line and an actual welding line. A robot arm that rotates a shaft and thereby rotates a workpiece; formed in accordance with the shape of the workpiece; one is a driving side connected to a control axis of the robot arm, and the other is a driven side separated from the control axis. And a pair of upper and lower clamp heads for clamping and unclamping the workpiece by moving the workpiece vertically, a yoke for independently supporting the two clamp heads so that they can rotate independently, and a driven side for unclamping the workpiece with both clamp heads. Clamp that holds the same clamp head in phase with the yoke and makes the driven clamp head free to rotate during clamping. A handling jig having a head phase holding mechanism and detachably attached to the robot arm; a yoke phase holding mechanism for holding the yoke in the same phase as the robot arm at least at the seam welding position.

At least at a carry-in and carry-out position, the yoke is rotated around a control axis before and during unclamping of the work by the upper and lower clamp heads, and the yoke is moved to a reference posture corresponding to the carry-in posture of the work. It is preferable to provide a yoke posture correcting mechanism for correcting the position.

The clamp head phase holding mechanism comprises a vertical guide groove provided on one of the yoke and the driven-side clamp head, and a guide projection provided on the other, which fits into the guide groove.

[0010] The yoke phase holding mechanism holds the yoke in the same phase as the robot arm by utilizing a posture change of the robot arm that has reached the seam welding position based on a height difference between the seam welding position and another place. .

[0011]

Embodiments of the present invention will be described below.

As shown in FIGS. 1 and 2, the apparatus according to the present invention includes a work (1), for example, a fuel tank for an automobile.
A carry-in device (2) and a carry-out device (3) arranged in parallel for carrying out and a seam welding machine (4) for performing seam welding
And an articulated robot (5) for transferring the fuel tank (1) between the carry-in device (2), the carry-out device (3) and the seam welding machine (4) while turning about the turning center (O).
And

[0013] The tip of the arm (7) of the articulated robot (5) is supplied with fuel via a control axis (9), a θ table (10), an XY table (11) and a commercially available tool changer (not shown). A handling jig (14) for supporting the tank (1) is mounted. The control axis (9) is an axis driven by a step motor or a servo motor capable of precisely controlling the rotation angle, and the terminal control axis of the robot can be used as it is. In the robot (5), the traveling direction of the electrode wheel of the seam welding machine (4) changes due to the unevenness of the peripheral flange portion (1c) of the fuel tank (1) and the like. Is detected when a deviation occurs in the control axis (9) in a direction to eliminate the deviation while allowing the deviation in the θ table (10) and the XY table (11).
To rotate the fuel tank (1) supported by the handling jig (14) to correct the welding direction. The tool changer supports the handling jig (14) in a detachable manner, and has a structure that can be easily replaced when the handling jig (14) is replaced by changing the model of the fuel tank (1).

A carriage (15) having a substantially U-shape in plan view is supported by the carry-in device (2) so as to be able to travel by itself. This trolley (1
5) Supports both side ends of the fuel tank (1) supplied from the previous process and transports the fuel tank to the carry-in position (A) provided at the end of the carry-in device (2). One positioning pin (not shown) is provided on each side of the cart (15), and the positioning pin is connected to the fuel tank (1).
The fuel tank (1) is positioned on the cart (15) by being inserted into pin holes (not shown) provided on both sides, and is transported to the carry-in position (A) in that state.

The unloading device (3) is composed of a roller conveyor or the like having a conveying surface inclined downward in the feed direction, and has a welded fuel tank (1) mounted on the unloading device (3).
Is transported to the next step by sliding on the transport surface by its own weight. A reversing mechanism (16) for reversing the fuel tank (1) is provided at the unloading position (B) adjacent to the start end of the unloading device (3). The reversing mechanism (16) supports the fuel tank (1) transferred to the unloading position (B) by the robot arm (7) with the U-shaped arm (17) in plan view.
This arm (17) is rotated 180 ° about the rotation axis (18).
It is turned upside down by rotating. The fuel tank (1) is loaded with its lower surface (1a: see FIG. 4) as a reference surface and is loaded with the upper surface facing upward, and is welded, but the posture is unchanged, that is, the upper surface (1b) is lower. In the condition (1), the protrusion such as the lubrication port on the upper surface (1b) hinders the removal of its own weight, so the fuel tank (1) is inverted by the reversing mechanism (16) and the almost flat lower surface (1a)
Was turned down before feeding to the unloading device (3).

As shown in FIG. 4, the handling jig (14) has a pair of upper and lower clamp heads (20) and (21) controlled by a substantially C-shaped yoke (22) for a control shaft (the axis of which is indicated by 9a). And coaxially and independently rotatably supported. The upper clamp head (20) is driven to rotate by the rotation of the control shaft (9) (drive side), and is detachably mounted on a tool changer.
The upper clamp head (20) has a plurality of claw members (23) for restraining the outer peripheral surface of the fuel tank (1). The claw members (23) are arranged at a plurality of positions over the entire circumference of the fuel tank (1), and the respective inner surface shapes and arrangement positions of the claw members (23) correspond to the outer peripheral surface shapes of the fuel tank (1) to be welded. Determined accordingly. On the other hand, the lower clamp head (21)
A plurality of work supporting portions (24) are provided (in a non-coupled state) separately from the control shaft (9) (in a non-coupled state) and support the upper surface (1b) of the fuel tank (1) at the upper end thereof. Are arranged. The work supporting portions (24) are arranged at different heights according to the unevenness of the bottom surface of the fuel tank (1). The number of the work supporting portions (24) is three in order to stably support the fuel tank (1). It is preferred that

An elevating mechanism for elevating and lowering the lower clamp head (21), for example, an air cylinder (26) is attached to the tip of the lower end of the yoke (22). This air cylinder (2
6) When the cylinder rod is protruded by driving, the lower clamp head (21) rises and the upper clamp head (2
The fuel tank (1) is clamped in cooperation with (0). Conversely, when the cylinder rod is retracted, the lower clamp head (21) descends and the fuel tank (1) is unclamped. As described above, in addition to raising and lowering only the lower clamp head (21), the upper and lower clamp heads (20) and (21) are raised and lowered, that is, both (20) and (21) are relatively moved in the vertical direction to work (1). May be clamped or unclamped.

A clamp head phase holding mechanism (27) is provided between the yoke (22) and the lower clamp head (21). When the fuel tank (1) is unclamped by the clamp heads (20) and (21), the phase holding mechanism (27) moves the driven clamp head (), that is, the lower clamp head (21), to the yoke (22). The lower clamp head (21) is free to rotate with respect to the yoke (22) at the time of clamping.
As shown in the figure, a guide member (30) having a vertical guide groove (29) fixed to the yoke (22) can be fitted to the guide groove (29) fixed to the lower clamp head (21). And a guided member (32) having the guide projection (31). The guide groove (29) and the guide protrusion (31) engage with each other when the fuel tank (1) is unclamped (shown by a solid line), and the guide protrusion (31) escapes from the guide groove (29) during clamping ( (Indicated by a two-dot chain line). The guide groove (29) is formed such that the width of the groove near the entrance (upper end) is increased toward the top so that the guide protrusion (31) is smoothly guided into the guide groove (29). With the above configuration, the guide projection (31) is inserted into the guide groove (29) during unclamping.
The lower clamp head (21) and the yoke (2
2) are positioned and held in phase, and can be rotated integrally. On the other hand, at the time of clamping, the guide projection (31) is
9), the engagement state between them is released, and the lower clamp head (21) is free to rotate with respect to the yoke (22). Therefore, when the control shaft (9) is rotated in this state, the upper and lower clamp heads (20) and (21) and the fuel tank (1) rotate integrally.

As described above, the guide groove (29) is located on the yoke (22) side, and the guide projection (31) is located on the lower clamp head (21).
The guide groove (29) is on the lower clamp head (21) side, and the guide protrusion (31) is on the yoke (2).
2) It may be provided on the side.

A plurality of types of the handling jig (14) are prepared according to the shape of the fuel tank (1), and are appropriately replaced according to the type of the fuel tank (1) to be welded, and are attached to the tool changer. Unused handling jigs are temporarily placed on a temporary table (33: see FIG. 1), and at the time of replacement, the robot arm (7) is turned to the vicinity of the temporary table (33) to perform a tool change by an appropriate automatic exchange mechanism.

In the handling jig (14), the yoke (22) is free to rotate except during unclamping. Therefore, during welding at the seam welding position (C), there is a possibility that the yoke (22) will rotate on its own and cause problems such as interference with the seam welding machine (4).

In view of this point, in the present invention, the yoke (22)
A yoke phase holding mechanism (35) for positioning and holding the yoke (22) in the same phase as the robot arm (7) at least at the seam welding position (C) is provided between the robot arm (7) and the robot arm (7). As the yoke phase holding mechanism (35),
For example, as shown in FIGS. 5 and 6, a guide arm (37) having a forked guide (36) at the lower end is attached to the robot arm (7), and the yoke (22) is placed between the guides (36). Can be inserted and removed. Generally, there is a height difference between the seam welding position (C) and other positions such as the carry-in position (A) and the carry-out position (B).
During the movement of these positions, a difference occurs in the posture of the robot arm (7), that is, the direction and the inclination angle of the arm (7). Therefore, if this posture change is used, the yoke (22)
Can be inserted into and removed from the guide (36). That is, as shown in FIG. 6, the robot arm (7) rises forward at the seam welding position (C) (shown by a solid line),
If the arm is lowered forward at the carry-in position (A) or the carry-out position (B) (indicated by the center line of the arm at that time), the guide (36) is lowered at the seam welding position (C). The yoke (22) fits into the (36), whereby the yoke (22) is held in phase with the robot arm (7). On the other hand, at the carry-in position (A) and the carry-out position (B), the guide (36) rises, so that the yoke (22) is moved by the guide (36).
(See FIG. 2), so that the yoke (22) is free to rotate. With the above configuration, the yoke (22) is fixed in phase with the robot arm (7) during seam welding, so that the yoke (22) does not interfere with the seam welding machine (4). Loading position (A) and unloading position (B)
In this case, since the yoke (22) becomes rotatable, for example, the phase of the yoke (22) can be adjusted to the reference posture corresponding to the carrying-in posture of the fuel tank (1). In addition, the lower end of the guide (36) is formed to be wider toward the lower side so that the yoke (22) can be inserted smoothly. The guide (36) may be provided on the robot arm (7) side, or may be provided on the yoke (22) side to engage with the robot arm (7).

The phase of the yoke (22) in the loading device (2) is adjusted by a yoke attitude correcting mechanism (39) disposed immediately below the loading position (A). As shown in FIG. 1, the robot arm (7) enters the carry-in position (A) in a state inclined on a horizontal plane with respect to the carry-in direction of the fuel tank (1). If 14) was similarly inclined, the upper and lower clamp heads (20) (2)
Positioning of 1) and fuel tank (1) could not be performed accurately,
Subsequent accuracy is not good. The yoke attitude correcting mechanism (39) prevents such a problem. As shown in FIG. 7, a pair of swinging members (40) are symmetrically arranged, and the swinging shaft (40) is arranged in the middle between them. The swing member (40) is swung about the swing shaft (41) by rotatably pivoting to the (41) and driving both swing members (40) by the cylinder (42). is there. The yoke (indicated by a dashed line in the figure) that has entered obliquely is pressed from both sides at its lower end by a pressing member (43) attached to the tip of both swinging members (40) (FIG. 8).
), And the posture is corrected straight (indicated by a broken line) so as to be parallel to the carrying direction of the carry-in device (2). At this time, the relationship between the robot arm (7) and the yoke (22) is broken as described above, and the yoke (22) can freely rotate, so that such posture correction is also performed smoothly.

A mechanism similar to the yoke attitude correcting mechanism (39) is also provided on the unloading device (3) side (see FIG. 1).
This is because, on the side of the unloading device (3), the fuel tank (1)
This is because when reversing the position, it is necessary to align the reversing mechanism (16) with the fuel tank (1) clamped by the handling jig (14). In this case, the unloading position (B)
The incoming posture of the yoke (22) is indicated by a dashed line in FIG. Also in this case, the posture of the yoke (22) is corrected to the reference posture by swinging the swing members (40). If the reversing mechanism (16) is not provided,
Since the above-described alignment is unnecessary, the yoke attitude correcting mechanism (39) on the unloading device (3) side may be omitted.

The device of the present invention has the above-described configuration. Hereinafter, the operation of the device of the present invention will be described with reference to FIG. In the flowchart of the figure, the left side shows the operation of the loading device (2), the seam welding machine (4) and the unloading device (3), and the right side shows the operation of the robot (5).

When the worker sets the fuel tank (1) at the loading port of the loading device (2) (a), the tank (1) is automatically transported to the loading position (A) by the bogie (15) (b). . At the same time, the robot arm (7) is in the loading position (A)
(C), and the yoke (22) is corrected to the reference posture by the yoke posture correcting mechanism (39) (d). At this time, the upper and lower clamp heads (20) and (21) are in the unclamped state, and the guide grooves (2
Since the 9) and the guide projection (31) are in the engaged state, the yoke (22) and the lower clamp head (21) are held in the same phase. Therefore, the fuel tank (1) on the bogie (15) and the lower clamp head (21) are simultaneously adjusted with the posture of the yoke (22).
Will also be aligned.

Next, the cylinder (26) of the handling jig (14) is activated to raise the lower clamp head (21),
Lift up the fuel tank (1) and clamp it between the upper clamp head (20) (e). After the clamp is completed, the guide projection (31) comes off the guide groove (29), so that the lower clamp head (21) is free to rotate with respect to the yoke (22), and the upper and lower clamp heads (20) and (21) and the fuel The tank (1) can rotate integrally. Simultaneously with the completion of the clamping of the fuel tank (1), the swinging member (40) of the yoke attitude correcting mechanism (39) returns to the initial attitude (unclamping) (f) shown by the two-dot chain line in FIG. Next, when the handling jig (14) is raised by the robot arm (7), the robot arm (the one-dot chain line in FIG. 5), which has been lowered forward, is raised forward (shown by a solid line). Thereby, the yoke (22) is fitted into the guide (36) of the yoke phase holding mechanism (35), and the phase of the yoke (22) and the robot arm (7) is fixed. In this state, the robot arm (7) is turned,
The clamped fuel tank (1) is transferred to the seam welding machine (4) (g), and its peripheral flange portion (1c: see FIG. 4)
Is seam-welded (h). At this time, since the yoke (22) and the robot arm (7) are fixed, the yoke (22)
Does not rotate and interfere with the seam welding machine (4).

After the welding is completed, the robot arm (7) is turned to transfer the fuel tank (1) to the unloading position (B) (i). Next, use the yoke attitude correction mechanism (39) to change the yoke (22)
Is returned to the reference posture by clamping (j), and the fuel tank (1) is unclamped and placed on the reversing mechanism (16). Thereafter, the yoke attitude correcting mechanism (39) is unclamped (l), the robot arm (7) is retracted to its original position (m), and the arm (17) of the reversing mechanism (16) is driven to drive the fuel tank. (1) is inverted (n), and the welded fuel tank (1) is transferred onto the unloading device (3). Unloading device (3)
The upper fuel tank (1) slides down by its own weight and reaches the carry-out port (p).

When changing the model of the fuel tank (1), the robot arm (7) is turned and the handling jig (14) is transferred to the temporary table (33) to perform a tool change.

[0030]

As described above, according to the present invention, a plurality of types of handling jigs are prepared for each work having a different shape, the handling jig corresponding to the supplied work is attached to the tip of the robot arm, and the remaining handling jigs are provided. The jig is temporarily placed on the temporary mounting table, and the currently used handling jig is automatically replaced with the handling jig supported by the temporary mounting table when switching the type of work. The changeover can be performed, and the equipment cost can be reduced and the changeover cycle time can be shortened. Also,
Most of the moving range of the workpiece is covered by the movement of the robot arm, and the handling jig can be reduced in size. This is a great advantage particularly in seam welding of a large workpiece.

When changing the type of work, it is sufficient if the handling jigs, especially the upper and lower clamp heads, are dedicated products corresponding to the shape of each work. The cost can be reduced as compared with the case where a tool or the like is used.

[Brief description of the drawings]

FIG. 1 is a plan view of the device of the present invention.

FIG. 2 is a side view of the device of the present invention.

FIG. 3 is a front view of a clamp head phase holding mechanism.

FIG. 4 is a side view of the handling jig.

FIG. 5 is a side view of the yoke phase holding mechanism.

FIG. 6 is a sectional view of a yoke phase holding mechanism.

FIG. 7 is a plan view of a yoke attitude correcting mechanism.

FIG. 8 is a side view of the yoke attitude correcting mechanism.

FIG. 9 is a diagram showing an operation flowchart according to the present invention.

[Description of Signs] 1 Workpiece (fuel tank) 2 Loading device 3 Unloading device 4 Seam welding machine 5 Robot 7 Robot arm 9 Control axis 14 Handling jig 20 Upper clamp head (drive side) 21 Lower clamp head (driven side) 22 Yoke 27 Clamp head phase holding mechanism 29 Guide groove 31 Guide projection 33 Temporary table 35 Yoke phase holding mechanism 39 Yoke attitude correction mechanism A Loading position B Loading position C Seam welding position

Claims (5)

[Claims] 1. A loading / unloading device arranged in parallel, a handling jig formed to correspond to the shape of a work and clamping and unclamping the work, a seam welding machine, and a handling jig capable of supporting the handling jig. A temporary receiving stand, the handling jig is detachably attached to the tip portion, and comprises a loading device, an unloading device, a seam welding machine and a robot arm for transferring the handling jig to the temporary receiving stand while turning, Prepare multiple types of handling jigs for each workpiece with different shapes, attach the handling jig corresponding to the supplied workpiece to the end of the robot arm, and temporarily place the remaining handling jigs on the temporary mounting table, Seam welding that automatically replaces the currently used handling jig with the handling jig supported by the temporary table when switching apparatus. 2. A seam welding apparatus comprising: a control shaft for transferring a workpiece to a carry-in position, a welding position, and a carry-out position, and eliminating a deviation between a scheduled welding line and an actual welding line at the welding position. A robot arm for rotating the workpiece and thereby rotating the workpiece; formed in accordance with the shape of the workpiece, one of which is a driving side connected to a control axis of the robot arm, and the other is a driven side which is separated from the control axis. A pair of upper and lower clamp heads for clamping and unclamping the work by moving relative to each other in the vertical direction, a yoke for independently supporting the two clamp heads so as to be rotatable independently of each other, and Holds the clamp head in phase with the yoke, and sets the clamp head on the driven side free for rotation during clamping. And a de phase holding mechanism, the handling jig detachably attached to the robot arm; yoke phase holding mechanism for holding the yoke at least seam welding position the robot arm in phase. 3. A yoke is rotated about a control axis before and at the time of unclamping of the work by the upper and lower clamp heads at least at a carry-in position of the carry-in and carry-out positions. 2. The seam welding apparatus according to claim 1, further comprising a yoke posture correcting mechanism for correcting the posture to a reference posture. 4. A clamp head phase holding mechanism comprising a vertical guide groove provided on one of a yoke and a driven side clamp head, and a guide projection provided on the other, which fits into the guide groove. The seam welding apparatus according to claim 2 or 3, wherein 5. A method in which a yoke phase holding mechanism holds a yoke in the same phase as a robot arm using a posture change of a robot arm reaching a seam welding position based on a height difference between the seam welding position and another place. Claim 2 or 3 which is
The described seam welding apparatus.