JP6474205B2 - Adsorption surface plate and welding robot system - Google Patents

Description

  The present invention relates to a suction surface plate for sucking and holding a thin plate workpiece and a welding robot system using the suction surface plate.

  Conventionally, when welding or machining is performed on a large thin plate workpiece, the workpiece is restrained to a surface plate by suction. For example, in Patent Document 1, a suction surface plate (restraint surface plate) including a cooling plate provided along a welding line of a thin plate-like workpiece and suction devices provided along the welding line on both sides of the cooling plate. It is shown. The suction device is provided with a vacuum box having a suction hole (through hole) that communicates the suction port that opens to the suction surface and the inside, a support member that is provided around the suction port, and a support member that is provided around the support member. And an airtight elastic ring member.

  In the suction surface plate having the above configuration, the inside of the vacuum box is evacuated by forced exhaust (pressure lower than atmospheric pressure by gauge pressure), and the thin plate-like workpiece placed on the suction surface plate is sucked into the suction port. At that time, the airtight elastic ring member is elastically deformed until the work comes into contact with the support member. Thereby, a workpiece | work and an airtight elastic ring member closely_contact | adhere, and between a workpiece | work and an airtight elastic ring member is sealed.

JP-A-7-001186

  When a thin plate-like workpiece held on the suction surface plate is welded, the workpiece is distorted (deformed) by heat input. For example, in the suction surface plate as in Patent Document 1, when a thin plate-like workpiece is deformed to cause undulations, a gap is generated between the airtight elastic ring member and the workpiece, and air leaks from the gap to cause a vacuum break. . Even if a vacuum break occurs at one suction port, the vacuum box communicates with the other suction ports, so the vacuum break propagates to other suction ports at once, and the suction force of the workpiece at each suction port increases. descend. As a result, the workpiece cannot be appropriately fixed to the suction surface plate, and welding defects such as a welding position shift easily occur.

  Therefore, when a thin plate workpiece is automatically welded by a welding robot, if a vacuum break occurs at any of the suction ports, the robot is stopped immediately and the welding is interrupted to prevent welding failure. Further, the welding from the welding interrupted point to the rear part is performed by manual welding by an operator, and it has been desired to improve the welding automation rate from the viewpoint of cost reduction and the like.

  The present invention has been made in view of the above circumstances, and even when vacuum breakage occurs on the suction surface plate, it is possible to continue automatic welding, and a suction surface plate for a thin plate workpiece and the same It aims at providing the welding robot system provided with.

The adsorption surface plate according to one aspect of the present invention is:
A table having a suction surface provided with a plurality of suction ports;
A seal member provided around the suction port on the suction surface;
A support member provided around the seal member on the suction surface;
A vacuum pipe having a vacuum chamber inside whose pressure is lower than atmospheric pressure;
A suction flow path connecting the suction port and the vacuum chamber;
The suction flow path has a throttle portion formed by surface contact in which fluid movement is allowed through a gap between the contacting surfaces, and the throttle portion is an annular shape provided in the suction flow path. and the step surface, the shaft portion inner periphery of the annular step surface is formed by the surface contact with the head of the inserted headed shaft is characterized in Rukoto.
In addition, the suction surface plate according to another aspect of the present invention,
A table having a suction surface provided with a plurality of suction ports;
A seal member provided around the suction port on the suction surface;
A support member provided around the seal member on the suction surface;
A vacuum pipe having a vacuum chamber inside whose pressure is lower than atmospheric pressure;
A suction flow path connecting the suction port and the vacuum chamber;
The suction flow path has a throttle portion formed by surface contact that allows fluid movement through the gap between the contacting surfaces,
The throttle portion is formed by a fine hole formed in an elastic body arranged in the suction flow path so as to block the suction flow path and communicating the upstream side and the downstream side.

  In the suction surface plate of the above configuration, when a vacuum break occurs at some suction ports, the atmosphere flows into the vacuum chamber through the suction flow path, but the air is introduced into the atmospheric vacuum chamber by the constriction provided in the suction flow path. Inflow is prevented, and the time until the vacuum break propagates to other suction ports can be delayed. That is, a longer time lag occurs than when there is no throttle part in the suction flow path after the vacuum breakage occurs at some suction ports until the workpiece is released from the suction fixation. For this reason, during this time lag, welding can be continued even if a vacuum break occurs in some suction ports. Therefore, even if a vacuum break occurs during the welding of one pass, the automatic welding of that pass can be continued. As a result, the number of manual welds by the operator is reduced, so that the welding automation rate can be improved.

  In the suction surface plate, the throttle portion can be formed, for example, by surface contact in a flow direction of a plurality of surfaces provided in the suction flow path or in a direction orthogonal to the flow direction. Further, for example, the throttle portion may be in surface contact with an annular step surface provided in the suction flow path and a head portion of a headed shaft body in which a shaft portion is inserted into an inner periphery of the annular step surface. Can be formed. In addition, for example, the throttle portion can be formed by a fine hole formed in an elastic body arranged in the suction flow path so as to close the suction flow path and communicating the upstream side and the downstream side. In this case, the elastic body and the suction pad functioning as the seal member may be integrally formed. In any of the above suction surface plates, it is possible to realize a throttle portion capable of providing a time lag from when the vacuum break occurs until the workpiece is fixed.

  The adsorption surface plate preferably further includes a compressed air supply device that supplies compressed air to the vacuum chamber. In the suction surface plate according to the present invention, since the throttle portion is provided in the suction flow path, an environment in which vacuum breakage is unlikely to occur is created, so that natural vacuum breakage occurs when releasing the workpiece suction fixation. Takes time. Therefore, if the compressed air is supplied to the vacuum chamber by the compressed air supply device when releasing the workpiece suction and fixing, the compressed air is ejected from the suction port, causing vacuum breakage, and quickly releasing the workpiece suction and fixing. Can do.

Moreover, a welding robot system according to another aspect of the present invention includes:
A table having a suction surface provided with a plurality of suction ports, a seal member provided around the suction port on the suction surface, a support member provided around the seal member on the suction surface, and a pressure of atmospheric pressure A suction pipe having a vacuum pipe having a lower vacuum chamber inside, and a suction flow path connecting the suction port and the vacuum chamber, and provided with a throttle portion formed by surface contact in the suction flow path. The board,
A welding robot that performs welding on a workpiece that is suction-fixed to the suction surface plate;
Pressure detecting means for detecting the pressure in the vacuum chamber of the adsorption surface plate;
And a stop control means for controlling the welding robot so as not to perform the processing after the next pass when a pressure value larger than a predetermined first reference pressure is detected by the pressure detection means during welding. It is.

  In the welding robot system configured as described above, when a vacuum break occurs at a part of the suction port of the suction surface plate, the atmosphere flows into the vacuum chamber through the suction channel, but the atmosphere is reduced by the constriction provided in the suction channel. Is prevented from flowing into the vacuum chamber, and the time until the vacuum break propagates to other suction ports can be delayed. That is, a longer time lag occurs than when there is no throttle part in the suction flow path after the vacuum breakage occurs at some suction ports until the workpiece is released from the suction fixation. For this reason, during this time lag, welding can be continued even if a vacuum break occurs in some suction ports. As a result, the number of manual welds by the operator is reduced, so that the welding automation rate can be improved.

  The welding robot system includes emergency stop control means for controlling the welding robot so as to immediately stop processing when a pressure value greater than a predetermined second reference pressure is detected by the pressure detection means during welding. Furthermore, you may provide. According to the welding robot system described above, if the workpiece is released and fixed due to a severe vacuum break during the construction of one pass, the welding robot will be stopped in an emergency if the workpiece is displaced greatly. There is no risk of damage.

  In the welding robot system, the welding robot is an arc welding robot, an arc voltage measuring unit that measures an arc voltage of the welding robot, and a voltage value that is out of a predetermined arc voltage range by the arc voltage measuring unit is welded. An emergency stop control means may be further provided for controlling the welding robot so as to immediately stop the machining when measured inside. According to the welding robot system described above, when the workpiece is released and fixed due to a severe vacuum break during the construction of one pass, the welding robot will stop in an emergency. There is no risk of damage. Also, the welding robot can be brought to an emergency stop even when the work being welded is greatly displaced due to other causes of vacuum breakage such as cracking of the work tacking part.

  In the suction surface plate according to the present invention and the welding robot system equipped with the suction surface plate, even if a vacuum break occurs on the suction surface plate, a time lag occurs between the occurrence of the vacuum break and the release of the workpiece suction and fixation. Therefore, automatic welding by the welding robot can be continued during the time lag.

It is a schematic block diagram of the welding robot system provided with the adsorption surface plate which concerns on 1st Embodiment of this invention. It is a block diagram which shows the control structure of a welding robot system. It is a partial top view of a suction surface plate. It is a figure explaining schematic structure of an adsorption surface plate. It is an expanded sectional view near an adsorption part. It is a figure explaining schematic structure of the adsorption surface plate when adsorbing a work. It is a figure explaining schematic structure of the adsorption surface plate which concerns on 2nd Embodiment of this invention. It is a top view of a suction surface plate. It is a figure explaining schematic structure of the adsorption surface plate when adsorbing a work. It is the figure which showed the adsorption | suction surface plate which concerns on the modification 1 of 1st Embodiment. It is the figure which showed the suction surface plate which concerns on the modification 2 of 1st Embodiment. It is the figure which showed the adsorption | suction surface plate which concerns on the modification 3 of 1st Embodiment. It is the figure which showed the adsorption | suction surface plate which concerns on the modification 4 of 2nd Embodiment.

[First Embodiment]
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a welding robot system 1 including a suction surface plate 2 according to the first embodiment of the present invention, and FIG. 2 is a block diagram illustrating a control configuration of the welding robot system 1. As shown in FIGS. 1 and 2, the welding robot system 1 includes an adsorption surface plate 2, a welding robot 3, a traveling device 4, a transport device 5, and a control device 6. The workpiece 10 processed by the welding robot system 1 is a large thin plate-shaped workpiece having a thickness of about 1 to 5 mm, for example, and a side length of about 2 to 3 m, for example. An example of such a workpiece 10 is a panel of a low temperature storage tank. Hereinafter, each component of the welding robot system 1 will be described.

  First, the adsorption surface plate 2 will be described. The suction surface plate 2 is means for holding the workpiece 10 in a predetermined position suitable for welding, and has a function as a workpiece fixing jig. 3 is a partial plan view of the suction surface plate 2, FIG. 4 is a diagram for explaining the schematic configuration of the suction surface plate, FIG. 5 is an enlarged sectional view of the vicinity of the suction portion 8, and FIG. It is a figure explaining schematic structure of the adsorption surface plate when it is.

  As shown in FIGS. 3 to 5, the suction surface plate 2 according to this embodiment includes a vacuum pipe having a vacuum chamber 85 therein (in this embodiment, the T-shaped joint 26 and the tube 24 in FIG. 6), and an upper surface. Is a suction flow path forming member that forms a suction flow path 7 connecting the table 22, which is the suction face 21, a plurality of suction openings 81 provided on the suction face 21, and the suction openings 81 and the vacuum chamber 85. The embodiment includes a table 22), a seal member 82 provided around the suction port 81 on the suction surface 21, and a support member 83 provided around the seal member 82 on the suction surface 21. The suction surface plate 2 is further provided with a free ball bearing 25 for smoothly moving the workpiece 10 on the table 22. The free ball bearing 25 is provided inside a hole 23 formed in the suction surface 21. The free ball bearing 25 is moved up and down by a lifting device 20 a such as an air cylinder between a use position protruding from the suction surface 21 and a retracted position retracted from the suction surface 21.

  The suction port 81, the seal member 82, and the support member 83 provided on the suction surface 21 form one suction portion 8. A plurality of suction portions 8 are regularly arranged on the suction surface 21 according to the present embodiment. Each suction port 81 is connected to the vacuum chamber 85 via the suction flow path 7, and a vacuum suction force is generated at the suction port 81.

  The suction flow path 7 according to the present embodiment is formed by a through hole 75 formed in the table 22. The through-hole 75 opens to the suction surface 21, and this opening serves as a suction port 81. However, the suction flow path forming member forming the suction flow path 7 is not limited to the table 22, and the suction flow path forming member may be, for example, a pipe.

  Further, the vacuum chamber 85 according to the present embodiment has a T-shaped joint in which one of the branch pipes 26a is inserted from below into the through hole forming the suction flow path 7, as shown in detail in FIG. 26 and a tube 24 connecting between the T-shaped joints 26. That is, the vacuum piping according to the present embodiment is the T-shaped joint 26 and the tube 24. However, the vacuum piping is not limited to these, and the vacuum piping may include, for example, a box provided on the table 22. The vacuum chamber 85 includes a vacuum source 28 such as a vacuum pump and an ejector forcibly evacuating the vacuum chamber 85, a switching valve 27 provided between the vacuum source 28 and the vacuum chamber 85, and compression into the vacuum chamber 85. A compressor 29 (compressed air supply device) for supplying air is connected. The vacuum chamber 85 is provided with a pressure sensor 20 for detecting the pressure inside the vacuum chamber 85. Note that two or more vacuum chambers 85 may be provided in the suction surface plate 2 according to the scale of the suction surface plate 2.

  When the inside of the vacuum chamber 85 configured as described above is evacuated by the operation of the vacuum source 28 (gauge pressure is lower than atmospheric pressure), the atmosphere is sucked into the vacuum chamber 85 from the suction port 81 through the suction flow path 7. The suction flow path 7 is provided with a throttle portion 71 having a remarkably small flow path area as compared with other portions. Such a throttle portion 71 is formed by surface contact in a flow direction of a plurality of surfaces provided in the suction flow path 7 or in a direction orthogonal to the flow direction. In such a throttle portion 71, since the surfaces forming the suction flow path 7 are in contact with each other, the apparent flow path area is zero or very small, but through the minute gap between the contacting surfaces. The fluid (gas) can be moved.

  In particular, as shown in detail in FIG. 5, the throttle portion 71 according to this embodiment includes an end surface 26 b of the branch pipe 26 a of the T-shaped joint 26 inserted in the suction flow path 7, and a shaft on the branch pipe 26 a. It is formed by surface contact with the head 73a of the headed shaft body 73 in which the portion 73b is inserted. Here, since the inner diameter of the branch pipe 26 a of the T-shaped joint 26 is smaller than the inner diameter of the through hole forming the suction flow path 7, the inside of the suction flow path 7 is directed upward by the end face 26 b of the branch pipe 26 a. An annular step surface 72 is formed. The outer diameter of the head 73a of the headed shaft 73 is smaller than the inner diameter of the through hole forming the suction flow path 7 and larger than the inner diameter of the branch pipe 26a. Furthermore, the outer diameter of the shaft portion 73b of the headed shaft body 73 is smaller than the inner diameter of the branch pipe 26a. Due to the size relationship between the branch pipe 26a and the headed shaft body 73 as described above, the lower surface of the head portion 73a of the headed shaft body 73 inserted into the suction flow path 7 from above and the step surface 72 in the fluid flow direction. Touching on the surface. As an example of specific numerical values of the size relationship between the branch pipe 26a and the headed shaft body 73, the outer diameter of the head portion 73a of the headed shaft body 73 is 14 mm, and the outer diameter of the shaft portion 73b is also 8 mm. The inner diameter of the suction channel 7 is 16 mm, and the inner diameter of the branch pipe 26a of the T-shaped joint 26 is 9 to 13 mm.

  The seal member 82 according to the present embodiment is a protrusion that surrounds the periphery of the suction port 81 and has an endless frame shape such as a square frame shape or an annular frame shape in plan view. The seal member 82 is made of a material that can be elastically deformed and has low air permeability. In the present embodiment, the seal member 82 is made of a closed cell rubber sponge. Therefore, the sealing member 82 has almost no air permeability and can be sealed with a small compression deformation rate.

  The support member 83 is an object that does not deform even when pressed against the workpiece 10 on which a vacuum suction force is applied, and is made of, for example, a hard resin material or a metal material. The support member 83 according to the present embodiment has an endless frame shape that is slightly larger than the seal member 82 in plan view. However, the shape of the support member 83 is not limited to this embodiment, and may be a series of a plurality of protrusions formed intermittently around the suction port 81, for example. The seal member 82 and the support member 83 are both protrusions protruding upward from the upper surface of the table 22, but the upper end of the seal member 82 from the upper surface of the table 22 is higher than the height from the suction surface 21 to the upper end of the support member 83. The height of is large. That is, the seal member 82 protrudes larger from the table 22 than the support member 83.

  Next, the welding robot 3 will be described. The welding robot 3 is an industrial robot that performs automatic welding. The welding robot 3 includes a robot arm 31, a welding torch 32 attached to the wrist of the robot arm 31, a robot controller 38 that controls the robot arm 31, and a welding machine 39 that supplies electricity and shielding gas to the welding torch 32. It has. The periphery of the welding robot 3 is surrounded by a safety fence (not shown).

  The welding robot 3 according to the present embodiment is, for example, an arc welding robot for performing TIG welding. Therefore, the welding torch 32 is configured to supply electricity, filler material, and shielding gas to the welded portion. The welding robot 3 further includes a filler material feeding device 34 that supplies a wire-like filler material to the tip of the welding torch 32, an AVC device (Arc Voltage Controller) 35, and the like.

  Next, the traveling device 4 will be described. The traveling device 4 is means for moving the welding robot 3. The traveling device 4 includes a pair of traveling rails 41 extending in the conveying direction of the workpiece 10, a portal-shaped traveling platform 42 spanned between the pair of traveling rails 41, and traveling that causes the traveling platform 42 to travel along the traveling rail 41. A driving device 43, a traverse rail 44 provided on the travel stand 42, a traverse stand 45 provided with a slider that travels on the traverse rail 44, and a traverse drive device 46 that causes the traverse stand 45 to travel along the traverse rail 44. I have. The traveling rail 41 and the traversing rail 44 are substantially orthogonal in a plan view.

  Next, the transport device 5 will be described. The conveying device 5 is means for carrying the workpiece 10 into the suction surface plate 2 and unloading the workpiece 10 from the suction surface plate 2. The transport device 5 is, for example, a roller conveyor, and includes a plurality of rollers 52 and a transport drive device 51 that rotationally drives the rollers 52.

  Next, the control device 6 will be described. The control device 6 is means for controlling the calculation and control of the welding robot system 1. The control device 6 includes a CPU, a ROM, a RAM, an I / F, an I / O, and the like (all not shown). The ROM stores programs executed by the CPU, various fixed data, and the like. Programs executed by the CPU are stored in various storage media such as a flexible disk, a CD-ROM, and a memory card, and are installed in the ROM from these storage media. The RAM temporarily stores data necessary for program execution. The I / F performs data transmission / reception with an external device (such as a personal computer connected to the control device 6). I / O inputs / outputs detection signals of various sensors. The control device 6 is configured to perform processing for realizing each function of the control device 6 described below by cooperation of software such as a program stored in the ROM and hardware such as a CPU. . The control device 6 may execute each process by a single CPU, or may execute each process by a combination of a plurality of CPUs or CPUs and a specific processing circuit.

  The control device 6 includes a surface plate control unit 61 that controls the operation of the suction surface plate 2, a welding robot control unit 62 that controls the operation of the welding robot 3, a travel control unit 63 that controls the operation of the travel device 4, It has at least functions as a transport control unit 64 that controls the operation of the transport device 5, a robot stop control unit 65 (stop control means), and a robot emergency stop control unit 66 (emergency stop control means).

  The surface plate controller 61 controls operations of the switching valve 27, the vacuum source 28 and the compressor 29. The welding robot control unit 62 controls operations of the filler material feeding device 34, the AVC device 35, the robot controller 38, and the welding machine 39. The AVC device 35 monitors the arc voltage of the welding torch 32 and moves the welding torch 32 relative to the workpiece 10 so that the arc voltage is maintained at a predetermined value. The travel control unit 63 controls the operations of the travel drive device 43 and the traverse drive device 46. Further, the transport control unit 64 controls the operation of the transport driving device 51. The robot stop control unit 65 and the robot emergency stop control unit 66 will be described in detail later.

  Here, the flow of welding of the workpiece 10 in the welding robot system 1 having the above configuration will be described. The operation of each component of the welding robot system 1 described below is not particularly specified but is performed by the control of the control device 6.

  First, the work 10 is carried into the suction surface plate 2 by the transport device 5. When the work 10 is carried into the suction surface plate 2, the free ball bearing 25 is in the use position, and after moving the work 10 to a predetermined position on the suction surface plate 2, the free ball bearing 25 is moved to the retracted position. . The workpiece 10 is lowered by its own weight and comes into contact with the seal member 82. Subsequently, the vacuum source 28 is driven and the switching valve 27 is opened. Then, the vacuum chamber 85 is depressurized to become a vacuum, and a vacuum suction force is generated at the suction port 81. By this suction force, the workpiece 10 is sucked by the suction port 81 and moves toward the suction surface 21, and the seal member 82 that receives the pressing force from the moving workpiece 10 is compressed and deformed. As shown in FIG. 6, when the seal member 82 is compressed and deformed, the seal member 82 and the work 10 are brought into close contact with each other, and the space between the seal member 82 and the work 10 is sealed.

  In principle, the seal member 82 is compressed until the workpiece 10 comes into contact with the support member 83 and further movement toward the suction surface 21 is restricted. However, when the flatness of the workpiece 10 is low, the workpiece 10 and the support member 83 may not be in contact with each other in some of the suction portions 8 because the workpiece 10 follows the unevenness of the workpiece 10 due to the amount of compressive deformation of the seal member 82. is there.

  As described above, the workpiece 10 is pushed to the atmospheric pressure by the pressure difference between the vacuum and the atmosphere in the vacuum region 88 surrounded by the seal member 82 and the workpiece 10, and the workpiece 10 is adsorbed to the adsorption surface 21. In this manner, the welding operation by the welding robot 3 is performed in a state where the workpiece 10 is sucked and fixed to the suction surface 21 of the suction surface plate 2. As welding progresses, the workpiece 10 is distorted by heat input to the workpiece 10. When the distortion of the workpiece 10 exceeds the range that can be absorbed by the elastic deformation of the seal member 82, a minute gap is generated between the seal member 82 and the workpiece 10 that are in close contact with each other, and the gap is formed in the vacuum region 88 from the gap. Gas breaks in and vacuum breaks up.

  When a vacuum break occurs in any of the suction portions 8 of the suction surface plate 2, the atmosphere is sucked into the vacuum chamber 85 from the suction portion 8 through the suction flow path 7. However, since the throttle portion 71 is provided in the suction flow path 7, the amount of atmospheric suction through the suction flow path 7 is smaller than that in the case where the throttle portion 71 is not provided. Therefore, even if a vacuum break occurs in some of the suction portions 8, a delay occurs until the vacuum break propagates to other suction portions 8. As a result, when the vacuum break occurs in some of the suction portions 8, the workpiece 10 does not immediately leave the suction surface 21, but until the workpiece 10 leaves the suction surface 21 after the vacuum break occurs in some suction portions 8. Cause a time lag. Since this time lag is longer than that in the case where there is no restriction in the suction flow path, automatic welding by the welding robot 3 is performed during this time lag even if a vacuum break occurs in some suction portions 8 of the suction surface plate 2. Can continue.

  The pressure sensor 20 (pressure detection means) measures the pressure in the vacuum chamber 85 during welding. The robot stop control unit 65 of the control device 6 monitors the detection value of the pressure sensor 20 (pressure detection means) during welding. Then, the control device 6 compares the pressure value detected by the pressure sensor 20 during welding with a predetermined first reference pressure, and if the detected pressure value becomes larger than the first reference pressure, the suction surface plate It is judged that the vacuum break of 2 was detected.

  When the vacuum stop of the suction surface plate 2 is detected, the robot stop control unit 65 of the control device 6 outputs a warning signal to the indicator lamp 69 and also outputs a stop signal to the welding robot 3 to stop the welding robot 3. Let However, when a vacuum break occurs during the welding of one pass, the control device 6 does not stop the welding robot 3 immediately, but stops the welding robot 3 after the welding process of that pass is completed. In other words, the control device 6 controls the welding robot 3 not to perform the processing after the next pass when a vacuum break occurs during the welding of one pass.

  As described above, even if a vacuum break occurs during welding of one pass, the workpiece 10 is generated after the vacuum break occurs so that automatic welding by the welding robot 3 can be continued until the welding of the pass is completed. The time lag is adjusted by the shape, material, etc. of the throttle part 71 until the distance from the suction surface 21 increases. For example, when the workpiece 10 is a large thin plate workpiece having a side of 2 to 3 m, the time lag is necessary for welding 2 to 3 m, which is the longest length of one pass after the vacuum break occurs. It is adjusted to be time. This eliminates the need for manual welding from the middle of a single pass as in the past, or reduces the number of manual welding locations by the operator compared to the conventional method, thereby improving the automation rate of welding. Can do.

  The robot emergency stop control unit 66 of the control device 6 also monitors the detection value of the pressure sensor 20 (pressure detection means) during welding. However, the functions of the robot emergency stop control unit 66 and the robot stop control unit 65 may be integrated into one function unit. The robot emergency stop control unit 66 compares the pressure value detected by the pressure sensor 20 with a predetermined second reference pressure, and immediately stops processing when the detected pressure value is greater than the second reference pressure. In this manner, an emergency stop signal is output to the welding robot 3 to stop the welding robot 3. Note that the second reference pressure is larger than the first reference pressure. When a severe vacuum break of the suction surface plate 2 occurs during welding in one pass, the work 10 is displaced greatly because the work 10 is released from being fixed to the suction surface plate 2. In this way, when a severe vacuum break occurs on the suction surface plate 2, the robot emergency stop control unit 66 functions as described above, so that the welding robot 3 is brought to an emergency stop, which may damage the workpiece 10. Absent.

  In the welding robot system 1 according to the present embodiment, in addition to the robot emergency stop control unit 66, the AVC device 35 also detects an emergency vacuum break of the suction surface plate 2 and makes the welding robot 3 emergency stop. It functions as a control means. The AVC device 35 includes a voltmeter (arc voltage measuring means) that measures an arc voltage during welding and a controller. Usually, the controller of the AVC device 35 compares the measured arc voltage with a preset reference voltage and compares the measured arc voltage with an electric slide (not shown) provided between the wrist of the robot arm 31 and the welding torch 32. To adjust the distance between the welding torch 32 and the workpiece 10 so that the arc voltage is kept constant.

  When a vacuum break occurs during welding and the workpiece 10 is separated from the suction surface 21, the distance between the workpiece 10 and the welding torch 32 is rapidly reduced, and the arc voltage is rapidly changed. Therefore, the controller of the AVC device 35 compares the measured arc voltage with a predetermined appropriate arc voltage range (upper limit threshold value and lower limit threshold value) and determines that the adsorption voltage has fallen out of the arc voltage range. Detects severe vacuum break in panel 2. Further, when a severe vacuum break of the suction surface plate 2 is detected, the controller outputs an emergency stop signal to the welding robot 3 so as to stop the processing immediately and stops the welding robot 3. However, the control device 6 may be responsible for the function of detecting vacuum breakage of the suction surface plate 2 and the function of outputting a stop signal to the welding robot 3. When a severe vacuum break occurs in the suction surface plate 2 in this way, the welding robot 3 functions as an emergency stop control means as described above, so that the welding robot 3 is emergency stopped, so that the workpiece 10 is damaged. There is no fear. Further, the welding robot 3 can also be brought to an emergency stop even when the workpiece 10 being welded is greatly displaced due to other causes of vacuum breakage (for example, cracking of a temporary attachment portion of the workpiece 10).

  When welding is completed without causing vacuum breakage on the suction surface plate 2 during welding, a positive pressure is applied to the vacuum region 88 of each suction portion 8 in order to release the suction of the workpiece 10. In the suction surface plate 2 according to the present embodiment, since the suction channel 7 is provided with the throttle portion 71, a situation in which vacuum breakage is unlikely to occur is created. Takes time. Thus, the vacuum break 88 is forcibly generated in the vacuum region 88 of each suction portion 8 so that the suction of the workpiece 10 is quickly released. Here, the switching valve 27 is closed and compressed air is supplied to the vacuum chamber 85 by the compressor 29. Thereby, air blows out from the suction port 81, the vacuum in the vacuum region 88 is broken, and the suction of the workpiece 10 is quickly released.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 7 is a diagram illustrating a schematic configuration of the suction surface plate 2 according to the second embodiment of the present invention, FIG. 8 is a plan view of the suction surface plate, and FIG. 9 is a view of the suction surface plate 2 when the work is being attracted. It is a figure explaining a schematic structure. The suction surface plate 2A according to the second embodiment differs from the suction surface plate 2 according to the first embodiment described above in the aspect of the suction portion 8 of the suction surface plate 2 and the aspect of the throttle portion 71. Therefore, in the following description, the suction portion 8A and the throttle portion 71A of the suction surface plate 2 according to the second embodiment will be described in detail, and the same or similar members as those of the above-described embodiment are denoted by the same reference numerals in the drawings. A description thereof will be omitted.

  7 and 8, the suction portion 8A of the suction surface plate 2A according to the second embodiment includes a suction pad 92 provided around the suction port 81, and a suction pad 92 on the suction surface 21. A support member 83 provided around is provided. The suction pad 92 functions as a seal member that seals the vacuum region 88 between the suction port 81 and the workpiece 10.

  The suction pad 92 has an axial base 92b and a conical pad 92a extending from the base 92b in a trumpet shape. The suction pad 92 protrudes larger from the suction surface 21 than the support member 83, and the height from the suction surface 21 to the upper end of the suction pad 92 is larger than the height from the suction surface 21 to the upper end of the support member 83.

  The base 92 b of the suction pad 92 is inserted into a through hole 22 a formed in the table 22. A suction flow path 7 is formed in the base portion 92b of the suction pad 92 by a through hole penetrating the base portion 92b in the axial direction. The through hole includes a micro hole 92c whose flow area is extremely limited. The opening of the suction flow path 7 is a suction port 81, and this suction port 81 is opened substantially at the center of the pad portion 92 a of the suction pad 92. The suction port 81 and the vacuum chamber 85 are connected by the suction flow path 7.

  The suction passage 7 is provided with a throttle portion 71A having a remarkably small passage area as compared with other portions. The narrowed portion 71A is formed as a fine hole 92c provided in the base 92b of the suction pad 92 that is an elastic body. The inner peripheral surfaces of the micro holes 92c are almost in contact with each other so as to close the micro holes 92c, and the apparent flow path area of the micro holes 92c is zero or very small. When a pressure difference is generated between the inlet and the outlet of the throttle portion 71A, a small amount of gas flows through the micro hole 92c expanded through elastic deformation or the micro flow path of the micro hole 92c.

  In the suction surface plate 2A having the above configuration, when the work 10 is placed on the suction surface plate 2A, the work 10 is lowered by its own weight and comes into contact with the suction pad 92. Subsequently, when the vacuum source 28 is driven to open the switching valve 27, the vacuum chamber 85 is depressurized to become a vacuum, and a vacuum suction force is generated at the suction port 81. With this suction force, the work 10 is sucked into the suction port 81 and moves toward the suction surface 21, and the work 10 presses the suction pad 92. As shown in FIG. 9, when the pad portion 92 a of the suction pad 92 that receives a pressing force from the workpiece 10 is elastically deformed, the suction pad 92 and the workpiece 10 are brought into close contact with each other, and the pad portion 92 a of the suction pad 92 and the workpiece 10 are brought into contact. Is sealed.

  In principle, the pad portion 92a of the suction pad 92 is compressed until the workpiece 10 contacts the support member 83 and further movement toward the suction surface 21 is restricted. However, when the flatness of the work 10 is low, the work 10 and the support member 83 may not be in contact with each other in the part of the suction portion 8A because the unevenness of the work 10 follows the deformation amount of the suction pad 92. .

  As described above, the workpiece 10 is pushed to the atmospheric pressure by the pressure difference between the vacuum and the atmosphere in the vacuum region 88 surrounded by the suction pad 92 and the workpiece 10, and the workpiece 10 is sucked to the suction surface 21. In this manner, the welding operation by the welding robot 3 is performed in a state where the workpiece 10 is sucked and fixed to the suction surface 21 of the suction surface plate 2. When the distortion generated in the workpiece 10 due to welding heat input to the workpiece 10 exceeds the range that can be absorbed by the elastic deformation of the suction pad 92, a minute gap is generated between the suction pad 92 and the workpiece 10 that are in close contact with each other, A gas flows into the vacuum region 88 from this gap, and a vacuum break occurs.

  As described above, when a vacuum break occurs in the vacuum region 88 of any suction part 8A of the suction surface plate 2A, the air is sucked into the vacuum chamber 85 through the suction flow path 7 in the suction part 8A. However, since the restricting portion 71 </ b> A is provided in the suction flow path 7, the amount of air sucked through the suction flow path 7 is smaller than that in the case where the restricting portion is not provided. Therefore, even if a vacuum break occurs in some of the suction portions 8A, there is a delay before the vacuum break propagates to the other suction portions 8A. As a result, the workpiece 10 is not immediately separated from the suction surface 21 after the vacuum break occurs, but a time lag is generated after the vacuum break occurs until the workpiece 10 is separated from the suction surface 21. Since this time lag is longer than that in the case where there is no throttle in the suction flow path, automatic welding by the welding robot 3 can be continued during this time lag even if a vacuum break occurs on the suction surface plate 2A. Therefore, even in the welding robot system 1 provided with the suction surface plate 2A according to the second embodiment, even if a vacuum break occurs during the welding process of one pass, the welding process is performed until the processing of that one pass is completed. Can be continued.

  Although the preferred first and second embodiments of the present invention have been described above, the above configuration can be modified as follows, for example.

  For example, as shown in FIG. 10, a suction pad 94 may be used in place of the seal member 82 in the suction surface plate 2 of the first embodiment. In this case, on the suction surface 21, a suction pad 94 is provided around the suction port 81, and a support member 83 is provided around the suction pad 94.

  Further, for example, in the first embodiment, the headed shaft body 73 is inserted into the branch pipe 26a of the T-shaped joint 26, but an annular step surface 72 is formed in the middle of the suction flow path 7, The headed shaft body 73 may be inserted into the suction flow path 7 so that the headed shaft body 73 contacts the stepped surface 72. In this case, the throttle portion 71 is formed by surface contact between the stepped surface 72 and the lower surface of the head portion 73 a of the headed shaft body 73.

  Further, for example, in the first embodiment, the suction passage 7 is provided with one throttle portion 71, but a plurality of throttle portions 71 may be provided in the suction passage 7. In this case, for example, as shown in FIG. 11, a shaft body 97 is provided in the upper and lower portions of the through hole 75 that forms the suction flow path 7. The throttle portion 71 is formed by surface contact between the inner surface of the through hole 75 forming the suction flow path 7 and the end surface of the shaft body 97.

  Further, for example, in the first embodiment, the throttle portion 71 is formed by surface contact in the fluid flow direction of a plurality of surfaces (the step surface 72 and the lower surface of the headed shaft body 73) provided in the suction flow path 7. ing. However, the throttle portion 71 may be formed by surface contact in a direction orthogonal to the fluid flow direction of a plurality of surfaces provided in the suction flow path 7. In this case, for example, as shown in FIG. 12, a plurality of filling members 96 a and 96 b are provided in the upper and lower portions of the through hole 75 forming the suction flow path 7. The filling members 96a and 96b are in surface contact with each other in a direction perpendicular to the fluid flow direction.

  Further, for example, in the suction surface plate 2A according to the second embodiment, the suction pad 92 has both a function as a seal member and a function as a forming body of the suction flow path 7 and the throttle portion 71A. However, these functions can be provided separately. In this case, for example, as shown in FIG. 13, a suction pad 94 is provided around the suction port 81 of the suction surface 21, and the suction channel 7 that communicates the suction port 81 and the vacuum chamber 85 is formed in the table 22. The elastic body 95 is inserted into the suction flow path 7. The suction pad 94 functions as a seal member. The elastic body 95 is a shaft-like member made of an elastically deformable material, and a micro hole 95a is provided in the shaft center portion. This fine hole 95 a becomes a throttle portion 71 A provided in the suction flow path 7.

DESCRIPTION OF SYMBOLS 1 Welding robot system 2 Suction surface plate 3 Welding robot 4 Traveling device 5 Conveying device 6 Control device 7 Suction flow path 71, 71A Restriction part 72 Step surface 73 Headed shaft body 8 Suction part 81 Suction port 82 Seal member 83 Support member 26 T-shaped joint 26a Branch pipe 29 Compressor (compressed air supply device)
8,8A Suction part 92 Suction pad 92a Pad part 92b Shaft part 92c Micro hole

Claims (8)

A table having a suction surface provided with a plurality of suction ports;
A seal member provided around the suction port on the suction surface;
A support member provided around the seal member on the suction surface;
A vacuum pipe having a vacuum chamber inside whose pressure is lower than atmospheric pressure;
A suction flow path connecting the suction port and the vacuum chamber;
The suction flow path has a throttle portion formed by surface contact that allows fluid movement through the gap between the contacting surfaces,
The throttle portion is formed by surface contact between an annular step surface provided in the suction flow path and a head of a headed shaft body in which a shaft portion is inserted on an inner periphery of the annular step surface. The adsorption surface plate. A table having a suction surface provided with a plurality of suction ports;
A seal member provided around the suction port on the suction surface;
A support member provided around the seal member on the suction surface;
A vacuum pipe having a vacuum chamber inside whose pressure is lower than atmospheric pressure;
A suction flow path connecting the suction port and the vacuum chamber;
The suction flow path has a throttle portion formed by surface contact that allows fluid movement through the gap between the contacting surfaces,
An adsorption surface plate, wherein the throttle portion is formed by a fine hole formed in an elastic body arranged in the suction flow path so as to block the suction flow path and communicating the upstream side and the downstream side. The suction surface plate according to claim 2 , wherein the elastic body and a suction pad functioning as the seal member are integrally formed.   The adsorption surface plate according to claim 1, further comprising a compressed air supply device that supplies compressed air to the vacuum chamber. The adsorption surface plate according to claim 2, further comprising a compressed air supply device that supplies compressed air to the vacuum chamber. A table having a suction surface provided with a plurality of suction ports, a seal member provided around the suction port on the suction surface, a support member provided around the seal member on the suction surface, and a pressure of atmospheric pressure A suction pipe having a vacuum pipe having a lower vacuum chamber inside, and a suction flow path connecting the suction port and the vacuum chamber, and provided with a throttle portion formed by surface contact in the suction flow path. The board,
A welding robot that performs welding on a workpiece that is suction-fixed to the suction surface plate;
Pressure detecting means for detecting the pressure in the vacuum chamber of the adsorption surface plate;
And a stop control means for controlling the welding robot so as not to perform the processing after the next pass when a pressure value larger than a predetermined first reference pressure is detected by the pressure detection means during welding. ,
Welding robot system. An emergency stop control means is further provided for controlling the welding robot so as to immediately stop machining when a pressure value larger than a predetermined second reference pressure is detected by the pressure detection means during welding. Item 7. A welding robot system according to item 6 . The welding robot is an arc welding robot,
Arc voltage measuring means for measuring the arc voltage of the welding robot;
An emergency stop control means is further provided for controlling the welding robot to immediately stop machining when a voltage value out of a predetermined arc voltage range is measured during welding by the arc voltage measuring means. Item 7. A welding robot system according to item 6 .

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