JP2009028767A - Robot welding method for revolving frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity by shortening a cycle time in a robot welding method for revolving frame. <P>SOLUTION: The robot welding method for welding and assembling the revolving frame of a construction machine using a welding robot includes: a carry-in step A10 of tacking and integrally forming the revolving frame, thereafter carrying-in and disposing it on a base; welding steps A30, A40 of performing both controls of welding with the welding robot in a horizontal position and welding with the welding robot in a vertical position in a state that the revolving frame is disposed on the base; and a carry-out step A50 of carrying-out the revolving frame weld in the welding steps A30, A40 from the base. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a robot welding method for a swing frame using a welding robot.

  Conventionally, in a working machine represented by a hydraulic excavator, a lower traveling body including a traveling device and an upper swing body mounted on the lower traveling body are manufactured in separate lines. For example, the assembly process of the lower traveling body is an assembly line in which a turning device and a traveling device are attached to the base frame, while the assembly process of the upper traveling body is an engine for the turning frame (swing frame). It is an assembly line to which a radiator and the like are attached. Thereafter, the turning frame of the upper turning body is attached to the lower traveling body via a turning device and is integrally formed.

  A swing frame as a framework of the upper swing body is roughly composed of a main frame and side frames fixed to the left and right of the main frame. The main frame is connected to and mounted with various working devices such as a boom device at a front portion thereof, and a drive unit such as an engine is mounted at a rear portion thereof, and is attached to a turning device of a lower traveling body. On the other hand, side frames on the left and right sides of the main frame are joined to the main frame with a cab (operator's boarding room), a fuel tank, and the like mounted thereon.

  In this way, the revolving frame is composed of small unit frames such as a main frame and a side frame, and these are joined together to form the whole integrally, thereby achieving common standardization of the frames. It can be assembled using the same side frame with respect to the revolving frame of the work machine. Further, the turning frame can be reduced in weight by adjusting the thickness of the member according to the rigidity and strength required for each frame (for example, Patent Document 1).

  By the way, as shown in FIG. 6, the main frame 7a and the side frame 7b generally have complicated shapes, and a welding line (that is, the main frame 7a and the side frame 7b) when these frames are integrally formed by welding. The joining part) also has a complicated shape. For example, A portion in FIG. 6 can be welded in a horizontal posture, but in B portion, the welding line is vertical and must be welded in a vertical posture. Therefore, in such a welding process of the swivel frame 7, usually, the entire swivel frame 7 is supported using a positioner device, and welding is always performed in a horizontal posture while adjusting the orientation of the swivel frame 7 so that the welding line is horizontal. Work is being carried out.

The procedure of a typical robot welding process for the revolving frame 7 will be described with reference to FIGS. FIG. 8 is a flowchart showing a robot welding process of a revolving frame according to the prior art, and FIG. 9 is a perspective view showing a conventional robot welding apparatus for welding and assembling the revolving frame according to the procedure shown in the flowchart of FIG.
As shown in FIG. 9, the robot welding apparatus 30 is configured by attaching a welding robot 24 to a rail 25 spanned between a pair of frame-shaped fixed frames 28. The rail 25 is provided to be slidable in the direction A in FIG. Further, the welding robot 24 is attached to the rail 25 via a moving device 27 so as to be slidable in the direction B in FIG. As a result, the welding robot 24 can move freely in the horizontal direction with respect to the fixed frame 28.

  A work positioner 23 for fixing the turning frame 7 in an arbitrary posture is provided below the moving range of the welding robot 24. The work positioner 23 is provided with a pair of clamp jigs 23a, and the posture of the swing frame 7 can be fixed by gripping the entire swing frame 7 between the clamp jigs 23a. Further, the work positioner 23 can be rotated in the direction C in FIG. 9 while holding the revolving frame 7.

  Thereby, the orientation of the welding line with respect to the welding torch of the welding robot 24 can be adjusted. A temporary placement table 21 for temporarily placing the swivel frame 7 is provided below the work positioner 23. The temporary table 21 is provided so as to be able to rise and fall with respect to the floor surface 29, and is tilted to the floor surface 29 side so as not to interfere with the turning frame 7 when the work positioner 23 holds the turning frame 7. It has become.

In the robot welding apparatus 30 configured as described above, the welding operation of the turning frame 7 is performed according to the flowchart shown in FIG.
First, the turning frame 7 in which the main frame 7a and the side frame 7b are preliminarily welded to each other is carried into the main welding device 30 (step X10). Subsequently, the temporary table 21 is controlled to the standing state shown in FIG. 9 with respect to the floor surface 29, and the turning frame 7 is installed on the temporary table 21 (step X20).

  Thereafter, a part of the welding operation by the welding robot 24 is performed with the revolving frame 7 still placed on the temporary table 21 (step X30). At this time, the part of the welding line of the revolving frame 7 that interferes with the clamp jig 23a (the part that is gripped by the clamp jig 23a of the work positioner 23 in the next step) is pre-welded. And the site | part pre-welded by step X30 is hold | gripped (clamp) by the clamp jig | tool 23a (step X40). Thereby, the posture of the turning frame 7 is fixed with respect to the work positioner 23.

The temporary table 21 is tilted to the floor 29 and stored. As a result, there are no obstacles to the movement around the revolving frame 7, so the remaining welding is performed by the welding robot 24 while adjusting the position of the revolving frame 7 with the work positioner 23 so that each welding line is horizontal. (Step X50). When the welding operation is completed, the temporary table 21 is set up again, the clamp of the revolving frame 7 by the clamp jig 23a is released (unclamped), and the revolving frame 7 is placed on the temporary table 21 ( Step X60). Then, the turning frame 7 that has finished the welding work is carried out by the transport vehicle (step X70). In the welding assembly process of the swivel frame 7, the swivel frame 7 is manufactured using the above flow as a cycle.
JP 2002-285577 A

  However, in the welding method as described above, there is a problem that it takes time to adjust the posture of the revolving frame 7 using the work positioner 23 and it is difficult to shorten the cycle time. In addition, an increase in cycle time due to operations such as clamping / unclamping of the revolving frame 7 and raising / lowering operations of the temporary table 21 is unavoidable, and there is also a problem that costs related to device maintenance of the clamp jig 23a and the temporary table 21 are also required. is there.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a robot welding method for a revolving frame that can improve the productivity by reducing the cycle time.

  In order to achieve the above object, a robot welding method for a turning frame according to the present invention as set forth in claim 1 includes a main frame attached to the lower traveling body via a turning device, and a side frame that extends in the left-right direction of the main frame. In a robot welding method for welding and assembling a revolving frame of a construction machine comprising a welding robot, a temporary attachment step of temporarily attaching the main frame and the side frame to form an integral, and an integral formation in the temporary attachment step A carrying-in process for carrying in and placing the swivel frame on the gantry, and a control for welding the main frame and the side frame with the welding robot in a horizontal posture with the swivel frame arranged on the gantry. Control the welding control of the main frame and the side frame with the welding robot in an upright position. A welding process, is characterized in that the revolving frame welded at the welding process and a unloading step for unloading from said cross bench.

  According to a second aspect of the present invention, there is provided a method of welding a revolving frame according to the present invention, in addition to the structure of the first aspect, wherein the welding step is performed in a state where the revolving frame is arranged on the gantry by the carrying-in step. A welding location confirmation step of confirming a welding location in the turning frame by a laser sensor provided in a robot hand of the welding robot, and exchanging the laser sensor provided in the robot hand with a welding torch. And a welding location welding process for welding the welding location confirmed in the detection process.

According to a third aspect of the present invention, there is provided a turning frame robot welding method according to the present invention. In addition to the configuration of the second aspect, in the welding location confirmation step, the welding locations are confirmed by operating a plurality of the welding robots simultaneously. In addition, in the welding location welding step, the welding locations are welded by operating the plurality of welding robots simultaneously.
According to a fourth aspect of the present invention, there is provided a method of welding a turning frame according to the present invention, in addition to the configuration of the third aspect, in such a manner that the turning frame is surrounded from four corners in the welding location confirmation step and the welding location welding step. The four welding robots are arranged.

  According to the robot welding method of the turning frame of the present invention (Claim 1), by controlling the posture of the welding robot and performing both the welding operation in the horizontal posture and the welding operation in the vertical posture, Even when the welding line between the main frame and the side frame is not horizontal, welding can be performed. That is, it is not necessary to change the posture of the swivel frame, and time for positioning can be saved. Further, by eliminating the work positioner and the clamp jig, it is possible to reduce these operation times and to further shorten the cycle time. Furthermore, since a welding line excluding work places in some manual welding processes can be welded with the posture of the swivel frame fixed, the temporary table can be fixed at a predetermined position.

  Moreover, according to the robot welding method of the turning frame of the present invention (Claim 2), the welding line can be accurately grasped by confirming the welding location in the turning frame in the welding location confirmation step. As a result, the welding operation can be performed correctly regardless of the arrangement and orientation of the swivel frame with respect to the gantry. Moreover, since the laser sensor and the welding torch are exchanged and attached to the robot hand, an error between the detection by the laser sensor and the construction by the welding torch can be reduced after proper maintenance.

In addition, according to the robot welding method of the turning frame of the present invention (Claim 3), by using a plurality of welding robots, it is possible to greatly shorten the time required for welding work and to improve productivity. it can.
Moreover, according to the robot welding method of the turning frame of the present invention (Claim 4), it is possible to efficiently perform the welding work while avoiding the operation interference between the welding robots.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 5 are diagrams for explaining a robot welding method of a turning frame according to an embodiment of the present invention. FIG. 1 is a flowchart showing a robot welding process according to the robot welding method. FIG. FIG. 3 is a perspective view showing an overall configuration of a robot welding apparatus for welding and assembling the swivel frame using the method, and FIG. 4 is a robot welding process. FIG. 5 is a schematic side view of the apparatus, and FIG. 5 is a schematic top view of the robot welding apparatus. The turning frame that is welded and assembled by this robot welding method will be described with reference to FIG. 6 as appropriate. FIG. 7 is a partially enlarged view of the swivel frame shown in FIG.

[Constitution]
[1. The entire]
The turning frame robot welding method according to the present invention is applied to the turning frame welding assembly process in the robot welding apparatus 10 shown in FIG. 3 with respect to the turning frame 7 shown in FIG.

  As shown in FIG. 3, the robot welding apparatus 10 includes a gantry 1 fixed to a floor surface 9, and four welding robots 2 for welding a revolving frame 7 conveyed on the gantry 1. It is configured with. Above each welding robot 2, rail members 3 extending horizontally in the X direction in FIG. 3 are provided, and the welding robot 2 is slidable in the X direction with respect to each rail member 3. It is suspended by.

  A pair of fixed frames 6 are erected around these welding robots 2. Each fixed frame 6 is formed in a frame shape including two column members 6 a fixed to the floor surface 9 and beam members 6 b that horizontally connect the upper ends thereof. The fixed frames 6 are arranged to face each other so that the beam members 6b are parallel to each other. The internal space surrounded by these fixed frames 6 serves as a welding work place for the revolving frame 7.

  Each rail member 3 is supported so as to be slidable in the Y direction in FIG. 3 with respect to the beam member 6 b of the fixed frame 6. Also, as shown in FIG. 3, two rail members 3 are attached to one beam member 6b. That is, each rail member 3 is configured to extend above the welding work place of the revolving frame 7 on which the gantry 1 is provided, and each rail member 3 can move horizontally in a direction perpendicular to the extending direction.

  The operation of each rail member 3 and the operation of each welding robot 2 can be individually controlled. That is, the four welding robots 2 can move freely in the X direction and the Y direction independently of each other. In the vicinity of each rail member 3, a pack wire 5 that accommodates a welding wire is also provided. The pack wire 5 is provided so as to be slidable with respect to the beam member 6 b together with the rail members 3.

  Between the pair of fixed frames 6, the above-described frame 1 is fixed to the floor surface 9. The gantry 1 is a work table used when the revolving frame 7 is welded. For example, when the turning frame 7 temporarily attached with the main frame 7a and the side frame 7b is carried in by a transport vehicle (not shown), it is placed on the gantry 1. In the robot welding method for the revolving frame, the welding operation is performed while the revolving frame 7 is placed on the gantry 1.

[2. Robot welding equipment]
The welding robot 2 of the robot welding apparatus 10 is a 6-axis vertical articulated robot.
As shown in FIG. 4, each welding robot 2 includes a robot base 2a, an articulated arm 2b, a robot hand 2c, a tool changer 2d, and a welding torch 2e. The robot base 2a has a built-in drive device (not shown) so that it can slide in the extending direction of the rail member 3 with respect to the rail member 3.

  The articulated arm 2b is a portion connected to the lower surface of the robot base 2a, and is supported so as to be rotatable in the horizontal and vertical directions (that is, with respect to two axes) with respect to the robot base 2a. Further, the multi-joint arm 2b is provided with three rotation axes (joints) (ie, three axes) for raising and lowering the multi-joint arm 2b itself. Thereby, the whole shape can be freely deformed by changing the rotation angle at each rotation shaft.

A robot hand 2c is connected to the lower end of the articulated arm 2b. The robot hand 2c is provided so as to be rotatable about an axis (one axis) extending in the connecting direction with respect to the articulated arm 2b.
Further, a tool changer 2d is fixed to the robot hand 2c. The tool changer 2d is an adapter device that detachably attaches various tools to the tip of the robot hand 2c. In FIG. 4, a welding torch 2e is attached to the tip of the tool changer 2d.

In addition, as shown in FIG. 3, the fixture 3a which can slide with respect to the rail member 3 with each welding robot 2 is being fixed to the upper side of the robot base 2a. The fixture 3a is a fixture for a replacement tool attached to the tip of the tool changer 2d. In the present embodiment, the fixture 3a includes a laser sensor 2f.
The laser sensor 2f is a sensing device that measures the shape and distance of an object in a non-contact state by measuring laser light reflected from the object. For example, it is possible to measure a gap width of a groove type of a welding location designated in advance. The information measured here is input to the robot control device 4 described later.

FIG. 5 shows a state where the turning frame 7 is placed on the gantry 1. Thus, two welding robots 2 of the robot welding apparatus 10 are provided for each fixed frame 6 and are disposed so as to surround the turning frame 7 from its four corners in a top view.
The work range of each welding robot 2 is set so as to overlap (i.e., wrap) each other. The broken lines shown in FIGS. 4 and 5 indicate the movable range (the range in which each welding robot 2 can move by controlling six rotation axes) when the sliding of each welding robot 2 with respect to the rail member 3 is fixed. ing. Here, in the arrangement state of the turning frame 7 such that the gantry 1 is located at the center of the turning frame 7, at least two welding robots 2 can reach any position of the main frame 7a. As shown in FIG. 4, the movable range in the vertical direction of each welding robot 2 extends from a position lower than the gantry 1 to the height of the rail member 3.

The operation of each welding robot 2 is individually controlled by the robot control device 4 shown in FIGS. Information relating to the overall shape of the revolving frame 7 and the welding location is input (teaching) in advance to the robot control device 4.
This robot control device 4 controls the position and orientation of the welding robot 2 (that is, the rotation angle control of the six rotation axes provided in the welding robot 2, the sliding position control of the welding robot 2 relative to the rail member 3, and the beam member) In addition to the control of the position of the rail member 3 with respect to 6b), the tool changer 2d controls the tool changeover operation and the operation control of each tool.

Various types of information measured by the laser sensor 2f described above are arithmetically processed inside the robot control device 4 and appropriately referred to during welding by the welding torch 2e. That is, the sensing work by the laser sensor 2f is mainly for the purpose of correcting the teaching contents.
In addition, the robot control device 4 according to the present embodiment is equipped with a control program that can perform the welding operation with the welding robot 2 not only in a horizontal posture but also in a vertical posture. That is, the welding robot 2 is controlled to a horizontal posture or a vertical posture according to the orientation of the welding line, and actual welding is performed. Thereby, welding work can be advanced regardless of the shape and orientation of the welding line. The robot welding apparatus 10 performs welding by using a known automatic welding technique such as high-speed feeding control or weaving control of a welding wire using a motor according to the attitude of the welding torch 2e.

  Further, the robot control device 4 can perform control for performing a welding operation in cooperation with respect to the two welding robots 2 arranged to face each other in the X direction in FIG. That is, two welding lines related to one member can be simultaneously welded using a pair of welding robots 2. In this embodiment, two sets of such a pair of welding robots 2 are provided.

[3. Swivel frame]
The turning frame 7 that is a work target in the robot welding apparatus 10 will be described in detail. As described above, the swivel frame 7 is formed by welding and assembling the main frame 7a and the side frame 7b. As shown in FIG. 6, thick brackets 7c are erected on the left and right sides of the main frame 7a. Each bracket 7c extends in the longitudinal direction of the vehicle body and extends rearward from the side frame 7b. A boom foot pin that pivotally supports the base of the boom is horizontally connected between the brackets 7c.

A counterweight base 8 for supporting the counterweight is provided at the rear portion of the main frame 7a. The counterweight base 8 is formed at the rear end of the bracket 7c.
As shown in FIG. 7, the counterweight base 8 includes a top plate 8a and side plates 8b. The side plate 8b is erected vertically in parallel with the bracket 7c, and the top plate 8a horizontally connects the upper end portion between the bracket 7c and the side plate 8b. The top plate 8a, the side plate 8b, and the bracket 7c are integrally formed by welding the small openings. In FIG. 7, reference numeral 8A is attached to the welding line between the top plate 8a and the bracket 7c, and reference numeral 8B is attached to the welding line between the top plate 8a and the side plate 8b.
As shown in FIG. 5, the counterweight base 8 is located in the overlapping region of the movable range of the welding robot 2 on the left and right (upper and lower in FIG. 5) of the turning frame 7.

[flowchart]
As a construction flow of robot welding according to this embodiment, a turning frame welding assembly process and a robot welding process will be described below. The swivel frame welding assembly process is a flowchart that roughly captures the process from the temporary attachment of the main frame 7a and the side frame 7b to the completion of the swivel frame 7. On the other hand, a robot welding process is a flowchart which performs welding operation using the robot welding apparatus 10 among turning frame welding assembly processes.

[1. Swivel frame welding assembly process]
The welding assembly process of the turning frame 7 in the robot welding apparatus 10 will be described with reference to FIG. First, in the temporary attachment process of step B10, the main frame 7a and the side frame 7b assembled in advance in another process are temporarily welded. In this process, the entire revolving frame 7 is integrally formed, but the main welding is not yet performed.

In the subsequent robot welding process of step B20, the robot welding apparatus 10 performs welding of the revolving frame 7 temporarily attached in the previous step. In this step, the main frame 7a and the side frame 7b are welded, and the counterweight base 8 at the rear end of the main frame is also welded.
Thereafter, in the manual welding process of step B30, the welding operator visually confirms the construction state of the robot welding apparatus 10, and also places the parts that cannot be welded by the robot welding apparatus 10 due to the structure by hand. And finally, the thermal distortion of each part of the turning frame 7 is corrected in the distortion removing process of Step B40, the turning frame 7 is completed, and the turning frame welding assembly process is completed.

[2. Robot welding process]
Next, the contents of the robot welding process using the robot welding apparatus 10 will be described in detail with reference to FIG. In the initial state, it is assumed that a laser sensor 2f is provided in the tool changer 2d of each welding robot 2. Further, it is assumed that the welding torch 2e is set on the fixture 3a.

  In Step A10, the turning frame 7 temporarily attached in Step B10 is carried into the robot welding apparatus 10 by the transport vehicle. In the subsequent step A20, the turning frame 7 is placed on the gantry 1. Since the gantry 1 is fixed to the floor, the position of the swivel frame 7 does not move while being placed on the gantry 1. The process of these steps A10 and A20 is a carry-in process.

  In the subsequent welding location confirmation process of Step A30, the position of the turning frame 7 is sensed by the laser sensor 2f, and the welding line is measured. Here, the shape data of the turning frame 7 inputted in advance is corrected by the measurement result of the laser sensor 2f, and an accurate welding location is confirmed. In this step, the four welding robots 2 are simultaneously operated, and the entire welding line of the turning frame 7 is sensed.

In the welding location welding process at step A40, the laser sensor 2f is replaced with the welding torch 2e in the tool changer 2d of each welding robot 2, and the welding location confirmed at step A30 is welded. At this time, the laser sensor 2f is set on the fixture 3a, and the welding torch 2e is attached to the tool changer 2d instead.
Furthermore, in this step A40, the working posture of the welding robot 2 is appropriately controlled by the robot control device 4, and both the welding in the horizontal posture and the welding in the vertical posture are performed. For example, since the welding line is horizontal in the vicinity of part A in FIG. 6, the welding robot 2 is controlled to perform welding in a horizontal posture. Further, since the welding line is vertical in the vicinity of part B, the welding robot 2 is controlled to perform welding in a vertical posture.

In this step, the four welding robots 2 are simultaneously operated to weld all the welding lines. Since each welding robot 2 is arranged so as to surround the four corners of the revolving frame 7, the welding operation is performed in parallel at four locations. In the counterweight table 8 in the region where the movable ranges of the welding robots 2 overlap each other, the welding work of two welding lines is simultaneously performed by the two welding robots 2. That is, in parallel with the welding line 8A between the top plate 8a and the bracket 7c being welded by one welding robot 2, the welding line 8B between the top plate 8a and the side plate 8b is welded by the other welding robot 2. Are welded at the same time. These steps A30 and A40 are welding processes.
When the welding operation of the revolving frame 7 is completed, the process proceeds to an unloading process in Step A50, where the revolving frame 7 is unloaded from the gantry 1 by the transport vehicle, and this robot welding process is completed.

[effect]
[1. Effect by structure and arrangement]
With the above configuration and control, the robot welding apparatus 10 according to the present invention has the following effects.

  First, by providing a pair of welding robots 2 that are controlled simultaneously, it is possible to perform welding at the same location using two welding torches. For example, by simultaneously welding the left and right end portions 8A and 8B of the top plate 8a of the counterweight base 8, thermal strain acting on the top plate 8a can be evenly distributed, and the welding accuracy can be increased. Thereby, for example, in the distortion removing process of step B40, the labor and time related to the distortion removing work can be shortened, and the cycle time of the welding assembly of the swivel frame 7 can be shortened.

  Further, since the welding robot 2 performs the welding operation not only in the horizontal posture but also in the vertical posture, the gantry can be fixed. That is, it is possible to carry out a welding operation having a complicated welding line shape without moving the turning frame 7 to be welded. This eliminates the need for a positioner, a clamp jig, a movable gantry, and the like for moving the revolving frame 7, thereby reducing the cost associated with device maintenance. In addition, the cycle time of the welding operation can be shortened.

  Moreover, by providing the welding robot 2 with the holdable laser sensor 2f, it is possible to perform welding after accurately grasping the shape of the welding line, and to improve the construction accuracy. Further, by switching between the laser sensor 2f and the welding torch 2e, it is possible to reduce the influence of fume and thermal radiation on the laser sensor 2f during welding after performing proper maintenance.

  Further, the tool changer 2d is provided in each welding robot 2 so that the welding torch 2e and the laser sensor 2f can be freely changed, whereby the tip shape of the welding robot 2 can be made compact. This also has the advantage of facilitating the confirmation and welding work of the narrow line welding line.

[2. Effect of control]
According to the robot welding method of the present invention, the welding line confirmation process is performed using the laser sensor 2f in the welding location confirmation step of Step A30. The shape data can be corrected. In particular, the welding line can be grasped quickly and accurately as compared with wire touch sensing in which the protruding length of the welding wire fed out from the welding torch 2e is measured. That is, the adjustment operation of the posture of the turning frame 7 can be made unnecessary, and the cycle time related to the welding assembly of the turning frame can be shortened.

  In the welding location welding process of step A40, each welding robot 2 is controlled to a horizontal posture or a vertical posture according to the orientation of the welding line, so that the welding work can be performed without changing the position and posture of the swivel frame 7. it can. That is, equipment such as the work positioner 23 and the clamp jig 23a according to the conventional technique can be eliminated, and the positioning operation time of the swivel frame 7 can be shortened.

  In addition, by freely controlling the posture of each welding robot 2, the welding operation can be correctly performed regardless of the arrangement and orientation of the turning frame with respect to the gantry. Further, since the laser sensor 2f and the welding torch 2e are replaced with the tool changer 2d, it is possible to reduce a control error between detection by the laser sensor 2f and construction by the welding torch 2e after proper maintenance.

  Furthermore, since it is possible to weld a welding line excluding a work place in some manual welding processes without moving the posture of the swivel frame 7, the swivel frame 7 is temporarily mounted like the temporary table 21 according to the prior art. The movable base for placing can also be abolished, and the base 1 can be fixed. Thereby, the cost concerning the apparatus maintenance of the clamp jig | tool 23a and the temporary mounting base 21 can be reduced, and the cycle time of an operation | work can also be shortened more.

  In the welding process of steps A30 and A40, since the four welding robots 2 are simultaneously operated and sensing and welding work are performed, the time required for the welding work can be greatly shortened, and the turning frame 7 Productivity can be improved. Further, as shown in FIG. 4, since the welding robot 2 is arranged so as to surround the turning frame 7 from its four corners, the operations of the welding robots 2 are unlikely to interfere with each other and the welding work can be performed efficiently. There is also an advantage of being able to do it.

Further, in the welding process, the process of confirming the welding location (Step A30) and the process of actually welding (Step A40) are separated, and the sensing work is completed prior to the actual welding, so that the laser sensor The influence of fumes and heat radiation on 2f can be reduced.
As described above, according to the robot welding method of the present invention, the cycle time related to the welding operation of the turning frame 7 can be shortened, and the productivity can be improved.

[Others]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, a robot welding method and a robot welding apparatus using four welding robots 2 are shown, but only one welding robot 2 is required. However, when performing simultaneous welding on one member like the counterweight base 8, it is desirable to provide at least two.

  Further, the welding torch 2e in the above-described embodiment may be capable of wire touch sensing using a welding wire. That is, it is good also as a structure which reconfirms a welding location using the detection result by wire touch sensing in a welding location welding process. In this case, the information regarding the turning frame 7 taught in advance in the robot controller 4 is corrected and confirmed twice in the welding location confirmation process and the welding location welding process. Therefore, a welding line can be grasped more accurately and construction quality can be further improved.

It is a flowchart which shows the robot welding process which concerns on the robot welding method of this invention. It is a flowchart which shows the welding assembly process of the turning frame weld-assembled using the robot welding method of this invention. It is a perspective view which shows the whole structure of the robot welding apparatus for welding assembly of a turning frame using the robot welding method of this invention. It is a typical side view of the robot welding apparatus for welding assembling a revolving frame using the robot welding method of the present invention. It is a typical top view of the robot welding apparatus for welding assembly of a turning frame using the robot welding method of the present invention. It is a perspective view which shows the whole structure of the turning frame of the working machine which concerns on this invention. It is a perspective view which expands and shows the principal part of the turning frame of the working machine which concerns on this invention. It is a flowchart which shows the robot welding process of the turning frame which concerns on a prior art. FIG. 6 is a schematic perspective view of a robot welding apparatus for welding and assembling a turning frame in a robot welding process according to a conventional technique.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stand 2 Welding robot 2c Robot hand 2d Tool changer 2e Welding torch 2f Laser sensor 3 Rail member 4 Robot control device 5 Pack wire 6 Fixed frame 7 Turning frame 7a Main frame 7b Side frame 8 Counterweight stand 10 Robot welding device

Claims (4)

In a robot welding method for welding and assembling a turning frame of a construction machine, which includes a main frame attached to a lower traveling body via a turning device and a side frame provided extending in the left-right direction of the main frame, using a welding robot,
A temporary attaching step of temporarily attaching the main frame and the side frame to form a single body;
A carry-in step of carrying in the swivel frame integrally formed in the tacking step and placing it on the frame;
With the swivel frame disposed on the gantry, the welding robot is placed in a horizontal position to control the main frame and the side frame to be welded, and the welding robot is placed in an upright position to form the main frame and the side frame. A welding process for performing both control and welding control;
A robot welding method for a swivel frame, comprising: a unloading step of unloading the swivel frame welded in the welding step from the gantry. The welding process
A welding location confirmation step of confirming a welding location in the turning frame by a laser sensor provided in a robot hand of the welding robot in a state where the turning frame is disposed on the gantry by the carrying-in step;
The laser sensor provided in the robot hand is replaced with a welding torch, and is configured to include a welding location welding process for welding the welding location confirmed in the welding location detection step. The robot welding method of the turning frame according to claim 1. In the welding location confirmation step, a plurality of the welding robots are simultaneously operated to check the welding location, and in the welding location welding step, the plurality of the welding robots are operated simultaneously to weld the welding locations. The robot welding method for a turning frame according to claim 2, wherein the robot frame is welded. 4. The robot welding method for a swing frame according to claim 3, wherein the four welding robots are arranged so as to surround the swing frame from four corners in the welding spot confirmation step and the welding spot welding step.

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