JP2003191184A - Work positioning tool for robot operation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform welding with a small number of robots and at various gun insertion angles in performing spot welding with a welding robot. <P>SOLUTION: A work base 6 for positioning and fixing a work W is made rotatable and a chain sprocket 13 is provided integral with the work base 6. A clutch mechanism 22 comprises the rotary base 8 of the welding robot 2 provided with a drive gear 11 and a driven gear 18 meshing with the drive gear 11 and a chain 14 is chained around a chain sprocket 19, which is positioned coaxially with the driven gear 18, and the chain sprocket 13 on the side of the work base 6. The work base 6 is made rotate according to the rotary operation of the welding robot 2 to positively change the attitude of the work W. After that, welding is performed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work positioning jig for robot work for positioning a work to be worked during robot work, and more particularly, on a work base of a work positioning jig which is arranged in the vicinity of an articulated robot. The present invention relates to a work positioning jig for robot work in which a work to be worked is positioned and fixed and then a predetermined work such as spot welding is performed by an articulated robot.

[0002]

2. Description of the Related Art In a sub-line for welding and assembling relatively small panel parts which form a part of a vehicle body panel, for example, as shown in FIG. 7, a work W is positioned by using a gauge or a clamper. Jig 51
A welding robot (a multi-joint type industrial robot having a spot welding gun on its wrist) 52 is positioned and fixed on the upper side and predetermined spot welding is performed. .

In this case, since the work W often has a complicated three-dimensional shape, the insertion angle of the spot welding gun (so-called approaching angle) necessarily depends on the work shape. The welding robots 52 are arranged with respect to the work positioning jig 51 in accordance with the restriction of the gun insertion angle, that is, in order to insert the spot welding gun most easily without interfering with the work W.

For example, the welding robot 52 is often a fixed-position type, and even if one welding robot 52 attempts to perform spot welding for all the required number of spots, as described above, the welding angle of the gun insertion angle is Since there are restrictions and the position of the spot welding gun that can be changed even if the robot arm is maximally extended is restricted as long as the welding robot 52 itself is of a fixed position type, therefore, in FIG. In consideration of being able to handle the welding of the works of the above vehicle types, it is unavoidable that two welding robots 52 are arranged and the welding work is shared by the respective welding robots 52.

[0005]

If a plurality of welding robots 52 are arranged due to the restriction of the insertion angle of the spot welding gun as described above, not only the equipment cost will rise, but also the welding robots 52 of both welding robots 52. Considering the interference between the spot welding guns of the one welding robot, for example, one welding robot 5
The welding time of the other welding robot 52 increases until the welding of the specific welding point by 2 is completed, and the operable time of each welding robot 52 cannot be fully allocated to the actual welding work time. As a result, even if two welding robots 52 are provided, the operating rates of the respective welding robots 52 are low, and the welding robots 52 are not always efficient as a whole.
Therefore, the welding work cannot be performed.

The present invention has been made in view of such conventional problems, and the work is positioned and fixed even when the insertion angle of the working machine such as the spot welding gun with respect to the work is restricted. By rotating the work base on the jig side, it is intended to provide a structure that enables efficient robot work without increasing the number of robots.

[0007]

According to a first aspect of the present invention, there is provided an articulated robot in which a work to be worked is positioned and fixed on a work base of a work positioning jig which is arranged in proximity to the articulated robot. It is a work positioning jig for robot work that is designed to perform a predetermined work by means of a swivel base that forms one of the rotational degrees of freedom of an articulated robot. While the robot arm is mounted, the work base is configured to be rotatable and positionable at an arbitrary rotation angle position, and the work base is mechanically interlocked with the swivel motion of the swivel base. It is characterized by rotating to the position. In this case, the working machine attached to the tip of the robot arm is, for example, a spot welding gun.

More specifically, as described in claim 2, a rotary power transmission means for rotating the work base in association with the turning motion of the turning base is provided between the turning base and the work base. Further, as described in claim 3, the rotary power transmission means includes:
It is assumed that a winding transmission means such as a chain for transmitting the swing power of the swing base to the work base is included.

In this case, as described in claim 4, it is preferable that the rotary power transmission means includes a clutch mechanism for connecting and disconnecting the power transmission from the turning base side to the work base side.

Therefore, in the invention described in claims 1 to 4, prior to the welding operation of the robot itself, the turning freedom of the turning base that forms a part of the articulated robot is effectively utilized. Rotate the work base to the specified position to change the work posture. By doing so, it becomes possible to secure the optimum insertion angle of the working machine with respect to the work. In particular, as described in claim 4, when the rotary power transmission means includes a clutch mechanism for connecting and disconnecting the power transmission from the turning base side to the work base side, the number of workpieces can be changed as many times as possible in one cycle. The posture can be changed, and the optimum insertion angle of the work machine with respect to the work can be secured each time.

The invention according to claim 5 is based on the description of any one of claims 1 to 4,
A robot arm is provided with a first arm attached to a revolving base and a second arm attached to the first arm, and the second arm is at least 180 degrees inverted from a position based on a stationary coordinate. It is characterized by being able to rotate up to.

Therefore, according to the fifth aspect of the present invention, for example, when the work base is rotated together with the work base by rotating the work base 180 degrees and the posture is changed, the work is performed in parallel with the work of the work base. When the second arm is turned over by 180 degrees, the second arm is in the same position as the original position when the turning operation of the turning base is completed. As a result, the welding operation can be immediately started when the change of the posture of the work is completed.

[0013]

According to the first aspect of the present invention, since the posture of the work on the work base is changed by utilizing the turning degree of freedom of the turning base of the articulated robot, a spot welding gun or the like for the work is provided. Since it is possible to secure the optimum insertion angle of the working machine, it becomes possible to perform efficient robot work without increasing the number of robots, which reduces the equipment cost and improves productivity. To do.

According to the second aspect of the present invention, the rotary power transmission means for rotating the work base in conjunction with the turning motion of the turning base is interposed between the two, and the third aspect of the present invention is also provided. According to the invention described above, since the rotation power transmission means includes the winding transmission means such as a chain for transmitting the rotation power of the rotation base to the work base, the rotation of the work base is controlled by the robot control system. Since all controls can be performed, there is no need to attach a rotation driving means or a control means to the work positioning jig side.
It has the advantages of simple structure and excellent operability and maintainability.

Further, according to the invention described in claim 4, since the rotary power transmission means includes a clutch mechanism for connecting and disconnecting the power transmission from the turning base side to the work base side, one cycle is performed. In addition, there is an advantage that the posture of the work can be changed at any timing and any number of times.

According to the fifth aspect of the invention, when the turning base is turned about 180 degrees and the posture of the work is changed in conjunction with the turning, the second movement is performed in parallel with the turning operation of the turning base. Since the arm can be reversed, there is an advantage that the workable area of the robot can be fully utilized and welding work can be performed efficiently.

[0017]

1 to 6 are views showing a preferred embodiment of the present invention, showing an example of spot welding of component parts of a vehicle body panel as shown in FIG. There is.

As shown in FIGS. 1 and 2, a rotary work positioning jig (hereinafter simply referred to as a positioning jig) 1 for positioning and fixing a work W to be worked is provided on the floor F. On the other hand, a multi-joint welding robot 2 is arranged as a fixed position fixed type industrial robot (teaching playback type industrial robot) close to the positioning jig 1, and the arm tip thereof is arranged. A spot welding gun (hereinafter, simply referred to as a welding gun) 3 is attached to the.

The positioning jig 1 comprises a pedestal 4 provided with a work base 6 rotatable about a vertical rotation axis 5.
The work W to be worked is positioned and clamped on the work base 6 by using a gauge or a clamper (not shown). The rotary shaft 5 is formed integrally with the work base 6, and the rotary shaft 5 is coaxially provided with a chain sprocket 13 that functions as a part of a rotary power transmission means described later. .

The welding robot 2 has a conventionally well-known structure and is equipped with a swivel base 8 which can swivel around a vertical axis in the direction of arrow a with respect to a fixed base 7, and the swivel base 8 has a first arm. 9 is rotatably connected in the direction of the arrow b, and the second arm 10 is attached to the tip of the first arm 9 by the arrow c.
Are connected so as to be rotatable in the direction, and a welding gun 3 rotatable in the directions of arrows d and e is attached to the wrist portion at the tip thereof. As a result, the welding robot 2 is configured as a multi-joint robot having a total of 5 degrees of freedom including the rotational degree of freedom of the swivel base 8. The rotation operation of each degree of freedom is performed by starting rotation driving means such as a built-in servo motor. Particularly, the swivel base 8 is used to start rotation driving means built in the fixed base 7. Based on this, the turning motion is performed.

Here, the second arm 10 of the welding robot 2
Has a degree of freedom of rotation of 180 degrees or more with respect to the first arm 9, and assuming that the state of FIG. 1 is the origin position state or the stationary coordinate position of the welding robot 2, the second arm 10 alone from that state. The first arm 9 can be rotated up and down to rotate to the inverted posture position shown in FIG. It should be noted that the operable area of the welding robot 2 alone is indicated by the reference symbol Q in FIGS. 1 and 6, and as is apparent from the drawings, the operable area Q is greatly enlarged on the rear side of the welding robot 2.

The rotating base 8 of the welding robot 2 is integrally provided with an external gear-shaped drive gear 11 having the same axis as the rotation center of the welding robot 2, and a gear box 12 is provided adjacent to the drive gear 11. There is. A chain 14, which is a winding transmission means, is wound between the gear box 12 and the chain sprocket 13 on the positioning jig 1 side, and the turning power of the turning base 8 when the turning base 8 turns, as will be described later. Is transmitted to the work base 6, and at the same time the work base 6 is rotated.

More specifically, FIG. 3 shows the details of the gear box 12, in which a part of the drive gear 11 is exposed inside the gear box 12 and the bracket 1
A driven shaft (pinion gear) 18 and a chain sprocket 19 capable of meshing with the drive gear 11 are provided on a rotary shaft 17 vertically provided on the vehicle. Driven gear 1
8 and the rotary shaft 17 are spline-coupled, the driven gear 18 can move in the axial direction of the rotary shaft 17 while rotating integrally with the rotary shaft 17, and the chain sprocket 19 can rotate the rotary shaft 17. It is formed as an integral unit with the shaft 17.

A bifurcated shift fork 20 is provided on the rotary shaft 17 so as to sandwich the driven gear 18 from above and below, and the shift fork 20 is a direct acting actuator 21 such as an air cylinder arranged adjacent to the bracket 15. Is connected to the piston rod 25. Therefore, as shown by the solid line in FIG.
When the driven gear 18 is moved upward and meshed with the drive gear 11, the turning power of the turning base 8 passes through the drive gear 11 → driven gear 18 → rotating shaft 17 → chain sprocket 19 → chain 14 → chain sprocket 13 to the work base. 6, the rotary power transmission means 30 from the turning base 8 side to the work base 6 side is formed by these respective elements.

On the other hand, conversely, when the driven gear 18 is moved downward by the shift fork 20, the engagement between the drive gear 11 and the driven gear 18 is released, and the power transmission from the turning base 8 side to the work base 6 side is cut off. It is supposed to be done. As described above, the driven gear 18 and the shift fork 20 that can move up and down among the above-described constituent elements are provided.
A clutch mechanism 22 that connects and disconnects the power transmission from the turning base 8 to the work base 6 is configured by the direct-acting actuator 21 and the like.

A sector gear or a rack-type fixed lock gear 23 is provided in the gear box 12 at a position corresponding to the lower side of the drive gear 11, and the driven gear 18 is not meshed with the drive gear 11. When it comes to a state, driven gear 18 replaces it.
Engages with the lock gear 23, and as a result, unnecessary movement of the driven gear 18 is prevented.

Further, as shown in FIGS. 1 and 2, a tensioner 24 elastically contacting the chain 14 is provided on the side of the positioning jig 1 so that an appropriate tension is applied to the chain 14. ing.

Therefore, according to the positioning jig 1 thus constructed, when the workpiece W to be welded is positionally clamped on the workpiece base 6, the welding robot 2 is activated and a preliminarily taught movement locus is obtained. The position of the welding gun 3 is appropriately changed so that the optimum gun insertion angle can be obtained while moving the welding gun 3 along the line, so that spot welding at required welding point positions is sequentially performed.

In this case, the insertion angle (approach angle or approach posture) of the welding gun 3, that is, the posture of the welding gun 3 that can be changed is naturally limited as long as the workpiece W and the welding robot 2 are in the fixed positions. As described above. Then, as shown in FIG. 5 in addition to FIG. 3, the driven robot 18 constituting the clutch mechanism 22 is moved upward at a predetermined timing as necessary to engage with the drive gear 11 and then the welding robot 2 is rotated. Rotate every 8 pieces.

Then, as the turning base 8 turns, its turning power is transmitted through the driven gear 18, the chain sprockets 13 and 19 and the chain 14 to the work base 6.
And the posture of the work W is changed in the horizontal plane as the work base 6 rotates. Then, when the work posture is changed by the required amount, the clutch mechanism 22 is immediately disengaged, and the welding robot 2 is immediately stopped in the revolving operation of the revolving base 8 or returned to its original position and stopped. After this, the welding robot 2 again performs spot welding at the required welding point position.

Here, the information regarding the rotation amount and the like for changing the posture of the work W is also taught in advance. Therefore, the posture change of the work W is also instructed from the robot control system as a part of the position control of the welding robot 2. It is executed based on. Further, the posture changing operation of the work W described above is repeatedly performed several times during one cycle of the welding operation, and it is shown in FIG. 5 when it is divided into blocks and illustrated.

As described above, even if the welding robot 2 is of a fixed position type, the posture of the workpiece W is positively changed by utilizing the degree of freedom of the swing of the swing base 8, and thus the workpiece W can be changed.
It is possible to change the insertion angle of the welding gun 3 to the arbitrary angle.

Here, the swing base 8 of the welding robot 2 is changed from the state shown in FIG. 1 to the state shown in FIG.
When it is necessary to rotate the arm 2 close to 0 degrees, the second arm 10 also moves from the state of FIG. 1 to the state of FIG. 6 by about 180 degrees in order to effectively use the operable area on the rear side of the welding robot 2. The second arm 10 is rotated so as to be substantially in the inverted position with respect to the position shown in FIG. By doing so, it becomes possible to immediately shift to the subsequent welding operation while the second arm 10 remains in the inverted posture of FIG. 6, and the cycle time can be used more effectively as the actual welding time. For example, the loss time occupying in the cycle time can be significantly reduced as compared with the case where the posture of the workpiece W is changed by the turning operation of the turning base 8 and then returned to a position convenient for welding, and the welding robot 2 is more efficient. Will be able to drive.

[Brief description of drawings]

FIG. 1 is a view showing a preferred embodiment of the present invention and is a side view showing a relationship between a work positioning jig and a welding robot.

2 is an explanatory plan view of FIG.

FIG. 3 is an enlarged sectional view of the gear box shown in FIG.

FIG. 4 is an explanatory plan view when the work base on the work positioning jig side is rotated along with the rotation of the turning base on the robot side.

5 is a flowchart showing a welding procedure by the welding robot and the workpiece positioning jig shown in FIG.

6 is an explanatory side view when the second arm of the welding robot shown in FIG. 1 is reversed.

FIG. 7 is an explanatory plan view showing the relationship between a conventional welding robot and a work positioning jig.

[Explanation of symbols]

1 ... Work positioning jig 2 ... Articulated welding robot 3… Spot gun (working machine) 6 ... Work base 8 ... Swivel base 9 ... First arm 10 ... second arm 11 ... Drive gear 12 ... Gear box 13 ... Chain sprocket 14 ... Chain (winding transmission means) 18 ... Driven gear 19 ... Chain sprockets 20 ... shift fork 21 ... Direct acting actuator 22 ... Clutch mechanism 30 ... Rotational power transmission means W ... work

Claims (5)

[Claims] 1. A work for robot work in which a work to be worked is positioned and fixed on a work base of a work positioning jig which is arranged in proximity to the articulated robot, and a predetermined work is performed by the articulated robot. A positioning jig, which is one of the rotational degrees of freedom of an articulated robot, is equipped with a robot arm having a work implement for robot work at its tip on a swivel base. Is rotatable and can be positioned at an arbitrary rotation angle position, and the work base is mechanically interlocked with the turning motion of the turning base to rotate the work base to an arbitrary position. Work positioning jig for robot work. 2. A rotary power transmission means for rotating the work base in association with the turning motion of the turning base is interposed between the turning base and the work base. The workpiece positioning jig for robot work described in. 3. The workpiece positioning jig for robot work according to claim 2, wherein the rotation power transmission means includes a winding transmission means for transmitting the swing power of the swing base to the work base. Ingredient 4. The rotating power transmission means includes a clutch mechanism for connecting and disconnecting the power transmission from the turning base side to the work base side.
The workpiece positioning jig for robot work described in. 5. The articulated robot includes a first arm attached to a swivel base as a robot arm and a second arm attached to the first arm, and the second arm uses a stationary coordinate as a reference. The workpiece positioning jig for robot work according to any one of claims 1 to 4, wherein the workpiece positioning jig can be rotated from the above position to a position inverted by at least 180 degrees.