JP2010094756A - Robot hand welding gun system and method of operating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot hand welding gun system capable of downsizing a robot hand, and a method of operating the system. <P>SOLUTION: The robot hand welding gun system 100 has a welding gun 200 for welding a workpiece 500 to be worked and the robot hand 300 for moving the workpiece connected to a tip of a robot arm 410. The robot hand welding gun system further includes carriers 310, 320 and 330 provided movably on the robot hand for holding the workpiece. The carriers are movable by their own weight between a holding position for holding the workpiece when moving it and a retreat position retreating from a welding gun when the workpiece is to be welded. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a robot hand welding gun system and an operation method thereof.

  As a device for welding and transporting workpieces, for example, as in Patent Document 1, a welding gun for welding a workpiece to be processed and a robot hand for moving the workpiece are connected to the tip of a robot arm. Robot hand welding gun system. The robot hand includes a clamp unit that holds a workpiece.

When the workpiece is welded by the welding gun, the clamp unit is moved to the retracted position retracted from the welding gun by an actuator provided in the robot hand so as not to interfere with the workpiece by interference with the workpiece. After welding, the clamp unit moves to the holding position for holding the workpiece by the actuator and grips the workpiece. Then, the robot arm is driven to carry the workpiece.
Japanese Patent Laid-Open No. 11-99494

  Since the technique described in Patent Document 1 welds and conveys workpieces by one robot, the equipment can be made compact compared to the case of using one robot for each welding gun and robot hand. .

  However, since the robot hand is provided with an actuator for moving the clamp unit to the holding position or the retracted position, it is difficult to make the robot hand compact, and there is a limit to making the entire robot hand welding gun system compact.

  The present invention has been made under such circumstances, and a robot hand welding gun system that can be made compact through making the robot hand compact, and an operation method of the robot hand welding gun system that is made compact. The purpose is to provide.

  In order to achieve the above object, a robot hand welding gun system of the present invention connects a welding gun for welding a workpiece to be processed and a robot hand for moving the workpiece to the tip of a robot arm. . The robot hand welding gun system further includes a holding unit for holding the workpiece, which is movably provided in the robot hand. The holding portion is movable by its own weight between a holding position for holding the workpiece when moving the workpiece and a retracted position for retracting from the welding gun when welding the workpiece.

  The operation method of the robot hand welding gun system of the present invention for achieving the above object includes a retraction step of moving the holding portion to a retraction position retracted from the welding gun by the weight of the holding portion, and a work by the welding gun. Welding process. When the welding process is completed, in order to move the workpiece, the holding portion is moved to a holding position for holding the workpiece by the weight of the holding portion (holding step).

  In the present invention, since the holding unit provided in the robot hand is moved by its own weight, there is no need to provide a driving device such as an actuator in the robot hand for moving the holding unit. The entire robot hand welding gun system can be made compact.

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

  FIG. 1 is a schematic configuration diagram of a robot hand welding gun system, FIG. 2 is a view as viewed from an arrow 2 in FIG. 1, FIG. 3 is a plan view of the robot hand, and FIGS. FIG. 5 is a side view of the robot hand, FIG. 6 is an arrow view from the arrow 6 in FIG. 5, and FIG. 7 is a side view of the robot hand for explaining the operation of the clamp unit. 8 and 9 are schematic views of the robot hand welding gun system in the retreat process. FIG. 10 is a schematic view of a robot hand welding gun system in the welding process. 11, 12, 13 and 14 are schematic views of the robot hand welding gun system in the holding process. FIG. 15 is a schematic diagram of a robot hand welding gun system when a workpiece is conveyed.

  As shown in FIG. 1, the robot hand welding gun system 100 has a welding gun 200 for welding a workpiece 500 to be processed. The robot hand welding gun system 100 also has a robot arm 410 with a plurality of joints for controlling operation. The welding gun 200 is connected to the tip of the robot arm 410. The tip 412 of the robot arm is a joint of the robot arm 410 and can rotate.

  The robot hand welding gun system 100 includes a robot hand 300 that is connected to a tip 412 of a robot arm 410 and moves a workpiece 500. The robot hand welding gun system 100 is movably provided in the robot hand 300, and includes clamp units (holding units) 310, 320, and 330 (see FIGS. 1 and 3) for holding the workpiece 500.

  The robot welding gun system 100 is also provided in the robot hand 300 and has rails (guide portions) 340, 350, 360 (see FIGS. 1 and 3) for guiding the movement of the clamp units 310, 320, and 330. The robot welding gun system 100 further includes a controller (control unit) 400 that controls the posture of the robot hand 300 by controlling the posture of the robot arm 410.

  The workpiece 500 is, for example, a rear floor panel of an automobile. The robot hand welding gun system 100 operates in the processing line of the workpiece 500. The robot hand welding gun system 100 sets the workpiece 500 on a jig (not shown) that supports the workpiece 500 by an operator or a robot for conveyance, welds the workpiece 500, and then conveys the workpiece 500. A plurality of different workpieces 500 flow in the processing line. The robot hand welding gun system 100 welds and conveys a plurality of different workpieces 500. The controller 400 has a configuration mainly composed of a CPU and a memory, and stores the entire operation of the robot hand welding gun system 100 in the memory.

  As shown in FIG. 2, the welding gun 200 has a main body 202 connected to the tip 412 of the robot arm, and a hook-shaped gun arm 204 extending from the main body 202. The gun arm 204 includes a fixed electrode 206 for welding the workpiece 500 at the tip. The welding gun 200 has a movable electrode 208 that faces the fixed electrode 206 and welds the workpiece 500 together with the fixed electrode 206.

  The movable electrode 208 is moved close to and away from the fixed electrode 206 by a servo motor built in the main body 202. The welding gun 200 sandwiches the workpiece 500 between the fixed electrode 206 and the movable electrode 208, and spot welds the workpiece 500 by flowing a secondary welding current between the fixed electrode 206 and the movable electrode 208. The controller 400 controls the operation of the servo motor in the main body 202 and the welding secondary current that flows between the fixed electrode 206 and the movable electrode 208.

  As shown in FIG. 3, the robot hand 300 includes three clamp units 310, 320, and 330. The robot hand 300 includes a T-shaped member 302 that forms the skeleton of the robot hand 300, and rails 340, 350, and 360 are provided along each of the three straight portions of the member 302.

  The clamp units 310, 320, and 330 are connected to the rails 340, 350, and 360, and are slidable along the rails 340, 350, and 360. The positional relationship between the three clamp units 310, 320, and 330 corresponds to the positional relationship between the vertices of the triangle. In addition, each of the clamp units 310, 320, and 330 can be independently moved by its own weight.

  The robot hand 300 has stoppers 341, 342, 351, 352, 361, 362 that prevent the clamp units 310, 320, 330 from coming off the rails 340, 350, 360 at both ends of each of the rails 340, 350, 360. Have.

  The robot hand 300 includes detection devices 343, 353, and 363 for detecting the clamp units 310, 320, and 330 at stoppers 341, 351, and 361 that are positioned in a direction in which the clamp units approach each other. The detection devices 343, 353, and 363 can use conventional techniques, for example, proximity sensors, limit switches, or reed switches. The detection devices 343, 353, and 363 are electrically connected to the controller 400.

  The clamp units 310, 320, and 330 move by their own weight between a holding position that holds the workpiece 500 when moving the workpiece 500 and a retracted position that retracts from the welding gun 200 when welding the workpiece 500. The holding position varies depending on the workpiece 500, and exists at different positions along the rails 340, 350, and 360.

  As shown in FIGS. 4A and 4B, for example, among the workpieces 502 and 504 having different sizes, the holding positions for holding the large workpiece 502 are close to the stoppers 342, 352, and 362. On the other hand, the holding position for holding the small work 504 is closer to the stoppers 341, 351, and 361. Further, the holding position differs depending not only on the size of the workpiece 500 but also on the shape of the workpiece 500 and the like.

  The retracted position is a position where the clamp units 310, 320, and 330 do not interfere with welding. In the present embodiment, the stoppers 341, 351, and 361 are positions where the clamp units 310, 320, and 330 are stopped.

  The controller 400 controls the posture of the robot hand 300 to place the clamp units 310, 320, 330 at any one of a plurality of holding positions at different positions along the rails 340, 350, 360. Move by its own weight.

  As shown in FIG. 5, the clamp unit 310 is connected to the rail 340 via a guide block 344 slidably engaged with the rail 340 and a slide base 346 connecting the guide block 344 and the clamp unit 310. Yes.

  A brake unit (brake) 345 for stopping the moving clamp unit 310 is engaged with the rail 340 so as to be slidable. The brake unit 345 is connected to the slide base 346.

  For the rail 340 and the brake unit 345, a known technique can be used, for example, the LMB series of CKD Corporation. Although it is a known technique, a detailed description is avoided here, but the interior of the brake unit 345 communicates with an intake path (not shown) for sending air and an exhaust path (not shown) for exhausting air. is doing. The brake unit 345 stops when the air is exhausted from the inside of the brake unit 345, and can move along the rail 340 when the air is pressed into the inside of the brake unit 345.

  A solenoid valve (not shown) communicating with the intake path and the exhaust path receives a signal from the controller 400 and switches the path. When the solenoid valve switches the path, air flows into the brake unit 345 or air flows out of the brake unit 345.

  As shown in FIG. 6, the clamp units 320 and 330 are also connected to the rails 350 and 360 with the same configuration as the clamp unit 310. A brake unit 355 having the same configuration as the brake unit 345 is connected to a guide block 356 for connecting the clamp unit 320 and the rail 350. A brake unit 365 having the same configuration as the brake unit 345 is connected to a guide block 366 for connecting the clamp unit 330 and the rail 360.

  As shown in FIG. 7, the clamp unit 310 includes a clamp 313 for gripping the workpiece 500 and a hydraulic cylinder 314 for opening and closing the clamp 313. The clamp unit 310 has two combinations of the clamp 313 and the hydraulic cylinder 314 (see FIG. 6).

  The clamp 313 has a pair of clamp claws 311 and 312 connected by a hinge 316 having a rotatable support structure. One clamp claw 312 is connected to a piston rod 315 extending from the hydraulic cylinder 314 and is rotated by a hinge 316 according to the expansion and contraction of the piston rod 315. As the clamp pawl 312 rotates, the clamp 313 opens and closes.

  The clamp units 320 and 330 have the same configuration as the clamp unit 310. That is, the clamp units 320 and 330 rotate one of the clamp claws by the hydraulic cylinders 324 and 334 to open and close the clamp. Unlike the clamp unit 310, the clamp units 320 and 330 have only one combination of a hydraulic cylinder and a clamp.

  An operation method of the robot hand welding gun system 100 will be described.

  The operation method of the robot hand welding gun system 100 includes a retracting step of moving the clamp units 310, 320, 330 to the retracted position retracted from the welding gun 200 by the weight of the clamp units 310, 320, 330. Further, the operation method of the robot hand welding gun system 100 includes a welding process of welding the workpiece 500 with the welding gun 200 after the retracting process. The operation method of the robot hand welding gun system 100 further holds the workpiece 500 by the clamp unit 310, 320, 330 by its own weight in order to move the workpiece 500 after the welding process. A holding step of moving to the holding position;

  In the retracting process, the clamp units 310, 320, and 330 are moved along the rails 340, 350, and 360 included in the robot hand 300 by controlling the posture of the robot arm 300 by controlling the posture of the robot arm 410. It moves by its own weight to the retreat position while the movement is guided.

  As shown in FIG. 8, in the retreat process, first, the controller 400 determines the posture of the robot hand 300 by moving the robot arm 410 in accordance with a program stored in the memory. At this time, the rails 340 and 360 are inclined with respect to the horizontal direction, and the clamp units 310 and 330 move toward the stoppers 341 and 361 when the brake units 345 and 365 are released.

  After determining the posture, the controller 400 releases the brake units 345 and 365, and slides the clamp units 310 and 330 along the rails 340 and 360 by their own weight. When the detection devices 343 and 363 (see FIG. 3) detect the clamp units 310 and 330 and the controller 400 receives a signal from the detection devices 343 and 363, the controller 400 stops the brake units 345 and 365, and the clamp unit 310 , 330 are fixed at the retracted position.

  Next, the controller 400 moves the robot arm 410 and rotates its tip 412 to determine the posture of the robot hand 300 as shown in FIG. The posture at this time is a posture in which the rail 350 is directed vertically and the clamp unit 320 moves toward the stopper 351 when the brake unit 355 is released.

  After determining the posture, the controller 400 releases the brake unit 355 and slides the clamp unit 320 along the rail 350 by its own weight. When the detection device 353 detects the clamp unit 320 and the controller 400 receives a signal from the detection device 353, the controller 400 stops the brake unit 355 and fixes the clamp unit 320 at the retracted position. After the clamp units 310, 320, and 330 are moved to the retracted position, the welding process is started.

  Referring to FIG. 10, in the welding process, first, the controller 400 moves the robot arm 410 to determine the position and posture of the welding gun 200 with respect to the workpiece 500. Thereafter, based on the signal from the controller 400, the welding gun 200 sandwiches the workpiece 500 between the fixed electrode 206 and the movable electrode 208, and causes the welding secondary current to flow between the electrodes to spot weld the workpiece 500. After welding, move to holding process.

  In the holding step, by controlling the posture of the robot arm 300 by controlling the posture of the robot arm 410, the clamp units 310, 320, and 330 are held at a plurality of different positions along the rails 340, 350, and 360. It moves by its own weight to one of the holding positions.

  As shown in FIG. 11, the robot hand welding gun system 100 includes a positioning jig 600 that positions the clamp units 310, 320, 330 by abutting the clamp units 310, 320, 330 that move by their own weight.

  The positioning jig 600 includes two poles 620 and 630 for abutting the clamp units 310, 320, and 330, and a base 610 that supports the poles 620 and 630. Further, the positioning jig 600 has detection devices 622 and 632 for detecting the clamp units 310, 320 and 330 at the tips of the poles 620 and 630. The detection devices 622 and 632 are the same as the detection devices 343, 353, and 363. The detection devices 622 and 632 are electrically connected to the controller 400.

  In the holding step, first, the controller 400 moves the robot arm 410 to determine the position and posture of the robot hand 300 with respect to the positioning jig 600. The position and posture of the robot hand 300 are such that the positions when the clamp units 310 and 330 slide and hit the poles 620 and 630 are the holding positions corresponding to the workpiece 500.

  When the position and posture of the robot hand 300 are determined, as shown in FIG. 12, the controller 400 releases the brake units 345 and 365 and slides the clamp units 310 and 330 along the rails 340 and 360 by their own weight.

  The clamp units 310 and 330 slide and abut against the poles 620 and 630. When the detection devices 622 and 632 detect the clamp units 310 and 330 and the controller 400 receives a signal from the detection devices 622 and 632, the controller 400 stops the brake units 345 and 365 and holds the clamp units 310 and 330 in the holding position. Secure to.

  Next, the controller 400 moves the robot arm 410 and rotates the tip 412 to determine the position and posture of the robot hand 300 with respect to the positioning jig 600 as shown in FIG. The position and posture of the robot hand 300 is such that the position when the clamp unit 320 slides and hits the pole 630 becomes the holding position corresponding to the workpiece 500.

  When the position and posture of the robot hand 300 are determined, as shown in FIG. 14, the controller 400 releases the brake unit 355 and slides the clamp unit 320 along the rail 350 by its own weight.

  The clamp unit 320 slides and hits the pole 630. When the detection device 632 detects the clamp unit 320 and the controller 400 receives a signal from the detection device 632, the controller 400 stops the brake unit 355 and fixes the clamp unit 320 to the holding position.

  After the clamp units 310, 320, and 330 have moved to the holding position, the controller 400 moves the robot arm 410 and moves the robot hand 300 toward the workpiece 500. As shown in FIG. 15, the robot hand welding gun system 100 grips the workpiece 500 by the robot hand 300 and conveys the workpiece 500, and moves the workpiece 500 to the next step.

  The effects of the embodiment will be described.

  Since the clamp units 310, 320, and 330 move by their own weight, this embodiment does not require a driving device such as an actuator for moving the clamp units 310, 320, and 330, and the robot hand 300 can be made compact. obtain. Further, in the present embodiment, the robot hand 300 can be made compact as a whole by making the robot hand 300 compact.

  The clamp units 310, 320, and 330 can move to any one of a plurality of holding positions at different positions. For this reason, this embodiment can hold | maintain the various workpiece | work 500 from which the position which should be hold | maintained, and is excellent in versatility.

  In the present embodiment, the clamp units 310, 320, and 330 hold various workpieces 500 having different positions to be held by moving and changing the holding positions. For this reason, the clamp unit does not move. For example, compared to a case where a large number of fixed clamp units are provided in advance in the robot hand so as to correspond to various workpieces, a variety of workpieces whose positions to be held differ by a small number of clamp units. 500 can be held. Therefore, this embodiment can improve versatility while suppressing an increase in the weight of the robot hand 300. Since an increase in the weight of the robot hand 300 can be suppressed, a heavier workpiece 500 can be conveyed accordingly.

  Since each of the three clamp units 310, 320, and 330 moves independently, the relative positions of the clamp units can be changed. Therefore, this embodiment can deal with a wider variety of workpieces 500 and has high versatility compared to a case where the relative positional relationship between the two clamp units is constant, for example.

  The number of clamp units may be two, for example, or four or more. However, when the workpiece 500 is held by two clamp units, it is unstable compared to the case of three as in the embodiment. Further, when the workpiece 500 is held by four or more clamp units, the workpiece 500 can be stably held, but the number of clamp units is increased and the weight of the robot hand 300 is increased as compared with the case of three.

  Therefore, as in the embodiment, the three clamp units 310, 320, 330 hold the workpiece 500, and the positional relationship of the three clamp units 310, 320, 330 corresponds to the positional relationship of the triangle vertices. It is preferable in terms of stability and weight reduction.

  In this embodiment, since the clamp units 310, 320, and 330 are stopped by the brake unit, the clamp units 310, 320, and 330 can be stopped at any position on the rails 340, 350, and 360. The clamp units 310, 320, and 330 can be positioned at the holding positions.

  Since the clamp units 310, 320, and 330 are positioned by abutting against the positioning jig 600, it is possible to prevent the clamp units 310, 320, and 330 that are slid and moved by their own weights from being shifted from the holding position and stopped.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, the holding part of the present invention only needs to hold the workpiece 500 when the workpiece 500 is moved, and may be a suction cup instead of the clamp, or may be a combination of a clamp and a suction cup. . However, it is less likely to be restricted by the surface shape of the workpiece 500 than the suction cup, and can handle various workpiece shapes. Therefore, a gripping unit such as a clamp unit is preferable.

  In addition, the positioning jig 600 is not limited to the embodiment, and any positioning jig may be used as long as it abuts the clamp unit. For example, another embodiment includes one having only one pole. In this case, the posture of the robot hand 300 is changed three times, and the clamping unit 310, 320, 330 and the pole are abutted three times to move the clamping unit 310, 320, 330 to the holding position.

  On the other hand, the positioning jig 600 of the present embodiment has two poles 620 and 630 and can position the two clamp units 310 and 330 by one posture change. Therefore, this embodiment can reduce the number of posture changes compared to the above-described example, and is preferable in terms of work efficiency.

  In addition, the detection devices 622 and 632 may be provided on the clamp units 310, 320, and 330, but the robot hand 300 can be reduced in weight by being provided on the positioning jig 600 as in the embodiment.

  Moreover, in this embodiment, although the workpiece | work 500 after welding is conveyed with the robot hand 300, this invention is not limited to this. That is, the workpiece 500 may be transported to the place to be welded by the robot hand 300 before welding, or the workpiece 500 may be transported by the robot hand 300 before and after welding.

It is a schematic block diagram of a robot hand welding gun system. It is an arrow view from the arrow 2 of FIG. It is a top view of a robot hand. It is a top view of a robot hand and a workpiece. It is a side view of a robot hand. It is an arrow view from the arrow 6 of FIG. It is a side view of the robot hand for demonstrating operation | movement of a clamp unit. It is the schematic of the robot hand welding gun system in an evacuation process. It is the schematic of the robot hand welding gun system in an evacuation process. It is the schematic of the robot hand welding gun system in a welding process. It is the schematic of the robot hand welding gun system in a holding process. It is the schematic of the robot hand welding gun system in a holding process. It is the schematic of the robot hand welding gun system in a holding process. It is the schematic of the robot hand welding gun system in a holding process. It is the schematic of a robot hand welding gun system when conveying a workpiece | work.

Explanation of symbols

100 robot hand welding gun system,
200 welding gun,
206 fixed electrode,
208 movable electrode,
300 robot hand,
310, 320, 330 Clamp unit (holding part),
311, 312 Clamp claw,
313 clamp,
314, 324, 334 hydraulic cylinder,
340, 350, 360 rail (guide part),
341, 342, 351, 352, 361, 362 stopper,
343, 353, 363, 622, 632 detector,
344 guide block,
346, 356, 366 slide base,
345, 355, 365 Brake unit (brake),
400 controller (control unit),
410 robot arm,
500 workpieces,
600 positioning jig,
620, 630 Paul.

Claims (7)

A welding gun connected to the tip of the robot arm and for welding the workpiece to be machined;
A robot hand connected to the tip of the robot arm for moving the workpiece;
A holding part for holding the work, the robot hand being movably provided;
The robot hand welding gun system that moves by its own weight between a holding position for holding the workpiece when moving the workpiece and a retracted position retracted from the welding gun when welding the workpiece . A guide unit provided in the robot hand for guiding the movement of the holding unit;
A controller that controls the posture of the robot hand by controlling the posture of the robot arm;
The control unit controls the posture of the robot hand to move the holding unit to one of a plurality of holding positions at different positions along the guide unit by its own weight. The robot hand welding gun system according to 1.   The robot hand welding gun system according to claim 1, further comprising a plurality of the holding portions, wherein each of the plurality of holding portions independently moves by its own weight.   The robot hand welding gun system according to any one of claims 1 to 3, further comprising a brake for stopping the holding portion.   5. The robot hand welding gun system according to claim 4, further comprising a positioning jig for positioning the holding unit by abutting the holding unit moving by its own weight. An operation method of a robot hand welding gun system in which a welding gun for welding a workpiece to be processed and a robot hand for moving the workpiece are connected to the tip of a robot arm,
A retraction step of moving the holding portion, which is provided in the robot hand so as to be movable, to a retraction position where the holding portion is retreated from the welding gun by the weight of the holding portion;
A welding step of welding the workpiece with the welding gun after the evacuation step;
A method of operating the robot hand welding gun system, including a holding step of moving the holding portion to a holding position for holding the workpiece by its own weight in order to move the workpiece after the welding step; . In the retracting step, by controlling the posture of the robot arm by controlling the posture of the robot arm, the holding portion is moved along the guide portion provided in the robot hand while the movement is guided. Moved by its own weight,
In the holding step, by controlling the posture of the robot arm by controlling the posture of the robot arm, the holding portion is one of a plurality of holding positions existing at different positions along the guide portion. The operation method of the robot hand welding gun system according to claim 6, wherein the robot hand welding gun system moves to the holding position by its own weight.

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