JP7680717B2 - Teaching tool and teaching method - Google Patents

Description

The present invention relates to a teaching tool for teaching the operation of a robot arm used in welding the butt joints of steel pipe columns, and a teaching method using the same.

Conventionally, at construction sites, the butt joints between steel pipe columns arranged vertically are fixed by welding. A known welding method for this purpose is a welding method using a robot arm (see, for example, Patent Document 1).

Patent document 1 describes a welding system in which a guide rail that goes around the steel pipe is fixed to the steel pipe, and a welding robot is moved along the guide rail to weld the butt joints between the steel pipes.

JP 2018-58078 A

In the above-mentioned Patent Document 1, the welding torch of the welding robot is moved along the butt joint between steel pipe columns arranged above and below, so the operation of the welding robot along the movement path of the welding torch is set according to the size (diameter) of the steel pipe column. Here, when a welding robot arm is used for the welding robot, such setting is performed by preparing a teaching steel pipe column equivalent to the column to be welded outside the construction site, and teaching the operation of the robot arm along the outer circumferential surface of the prepared steel pipe column.

However, when teaching the robot arm how to move, there are multiple sizes of steel pipe poles to be welded at the construction site, and the curvature of the corners of the steel pipe poles varies depending on the plate thickness (wall thickness) of the steel pipe poles. For this reason, it is necessary to prepare steel pipe poles for teaching purposes that match these steel pipe poles.

The present invention was made in consideration of these points, and aims to provide a teaching tool that can easily teach the operation of a welding robot arm without having to prepare steel pipe columns of different sizes for teaching, and a teaching method using the same.

In order to solve the above problem, the teaching tool of the present invention is a teaching tool for teaching the operation of a welding robot arm used for welding the butt joints of steel pipe columns arranged above and below, by moving the tip of the welding robot arm along the butt joints, and the steel pipe column has a polygonal outer surface having multiple straight lines and arc-shaped corners connecting the straight lines in a cross section perpendicular to the axial direction, and the teaching tool has a straight member that forms at least a part of the straight lines and a corner member that forms the arc-shaped corners and connects the straight members. The straight members and the corner members are composed of a first set of straight members whose number corresponds to the shape of the polygon, and a second set of corner members whose number corresponds to the shape of the polygon, and the first set and the second set are connected to each other to produce a jig body corresponding to the steel pipe column, and the first set has multiple types of sets whose parts corresponding to the straight line portion of the straight members have different lengths, and the second set has multiple types of sets whose parts corresponding to the arc-shaped corner portions have different radii of curvature.

According to the present invention, the path for moving the tip (welding torch) of the welding robot arm along the jig body, which is likened to the butt joint between the columns, can be set, and the operation of the robot arm can be taught. Here, in the present invention, the first set composed of straight members and the second set composed of corner members are composed of multiple types of sets, so that the jig body can be made by selecting from multiple types of straight members and corner members according to the steel pipe column. As a result, even if a teaching steel pipe column according to the size to be actually welded is not prepared, the teaching jig made according to the size of this steel pipe column is lightweight, easy to work with, and highly safe. As a result, the operation of the welding robot arm can be taught in advance using such a teaching jig at low cost and easily.

Here, the corner members of the teaching jig are not particularly limited, but a preferred embodiment is characterized in that each end of the corner members forms part of the straight portion.

According to this aspect, the connecting portion connecting the first set of straight members and the second set of corner members is formed in a straight line offset from both ends of the arc-shaped corner, and both ends of the arc-shaped corner are formed midway through the corner members. As a result, it is possible to more accurately identify the positions of both ends of the arc-shaped corner with respect to the fabricated jig body. This makes it possible to more accurately teach the operation of the welding robot arm.

In a more preferred embodiment, at least one of the portions where the straight member and the corner member are connected is made of a soft magnetic material, and a magnet is attached to the other portion.

According to this aspect, one of the parts made of a soft magnetic material is attracted by a permanent magnet attached to at least the other part where the straight member and the corner member are connected, so that the straight member and the corner member can be reliably connected with a simple operation. Moreover, the connection can be performed instantly, so it is easy to operate. For example, the part where the straight member and the corner member are connected may be the end face of these members, or may be the side face of these members (for example, the side face on the inner circumference side).

In a more preferred embodiment, a backing plate is fixed to either the straight member or the corner member, which abuts against the inner surface of the surface of the other member that is located inside the polygon, and the backing plate and the other member have insertion holes through which connecting bolts are inserted when the backing plate and the other member are overlapped to connect the straight member and the corner member.

According to this aspect, a backing plate is fixed to either the straight member or the corner member, and abuts against the inner surface of the surface of the other member that is located inside the polygon. Therefore, by inserting a connecting bolt while the backing plate and the other member are overlapped, the straight member and the corner member can be securely connected.

In a further preferred embodiment, the teaching jig is provided with a fixed column that fixes the jig body, and when the straight members and the corner members are connected, each of the straight members is removably fixed to the fixed column.

According to this embodiment, the jig body made by connecting the straight member and the corner member is detachably fixed to the fixed column, so that jig bodies of different sizes can be selected and fixed to the fixed column. Therefore, even if the jig body is compatible with columns of different sizes, the operation of the welding robot arm can be taught in the same way.

The teaching method according to the present invention is a teaching method using any of the teaching jigs described above, and is characterized in that the first and second sets corresponding to the shape of the steel pipe column are selected from the multiple types of first sets and multiple types of second sets, the jig body corresponding to the steel pipe column is fabricated using the selected first and second sets, and the jig body is treated as the butt portion between the columns, and the tip of the welding robot arm is brought into contact with a gap along a path along the outer circumferential surface of the jig body, thereby teaching the operation of the welding robot arm.

According to this teaching method, multiple types of jig bodies corresponding to steel pipe columns can be produced by combining and connecting straight members that form at least a part of the straight section of the steel pipe column and corner members that form the arc-shaped corners of the steel pipe column and are connected to each other. By contacting the tip of the welding robot arm with a gap in the path along the outer circumferential surface of the jig body of the teaching jig, the operation of the welding robot arm can be easily and inexpensively taught to the welding robot at a location other than the construction site, without having to prepare a teaching steel pipe column that corresponds to the column at the construction site.

The teaching tool of the present invention makes it easy to teach the operation of a welding robot arm without having to prepare steel pipe columns of different sizes for teaching.

FIG. 1 is an elevational view of a main portion of a steel pipe column in which a butt joint is welded using a teaching jig according to the present invention. 2A is a horizontal cross-sectional view of a column showing an example of a moving path of a welding torch of a robot arm that welds the butt portion of the steel pipe column shown in FIG. 1 , and FIG. 2B is a horizontal cross-sectional view of the steel pipe column. 1 is a plan view of an embodiment of a teaching tool according to the present invention; 4 is a partially cut-away elevational view along line AA of the teaching jig shown in FIG. 3. FIG. 5 is a perspective view of a main part of a jig body of the teaching jig shown in FIGS. 3 and 4 . 6 is an exploded perspective view of one corner member of the jig body shown in FIG. 5 . FIG. 5 is a plan view of a plurality of sets of straight members of the teaching tool shown in FIGS. 3 and 4, each having a different size. FIG. 5 is a plan view of a plurality of sets of corner members of the teaching tool shown in FIGS. 3 and 4 having different sizes. 1 is a schematic perspective view showing a teaching jig for explaining a teaching method according to an embodiment of the present invention and a welding robot arm. FIG. 5A to 5C are explanatory diagrams of a teaching method using a teaching jig according to the present embodiment. FIG. 5 is a plan view of a teaching jig according to another embodiment, which uses straight members and corner members of different sizes from those of the teaching jig shown in FIGS. 3 and 4 . 12 is a partially cut-away elevational view along line BB of the teaching jig shown in FIG. 11. FIG. 11 is an exploded perspective view of one corner member of a teaching jig according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a teaching tool according to the present invention will be described in detail with reference to the drawings.
First, the configuration of the vicinity of the butt portion of the steel pipe pole will be described in detail with reference to Fig. 1. Fig. 1 is an elevational view of a main part of the butt portion of the steel pipe pole.

In FIG. 1, the steel pipe column 1 has a butt joint 2 between two steel pipe columns arranged above and below. The lower steel pipe column 1A and the upper steel pipe column 1B are rectangular steel pipe columns, but are not limited to this and may be rectangular steel pipe columns of a polygon other than a rectangle (specifically, a polygonal steel pipe with four or more sides), and are not particularly limited as long as they are rectangular steel pipe columns with R parts (curvature) at the corners.

The upper end surface 2a of the lower steel pipe column 1A is a flat surface (horizontal surface) along a generally horizontal direction, and the lower end surface 2b of the upper steel pipe column 1B is a tapered surface inclined along the horizontal direction, and a welding groove 2c is formed between the upper end surface 2a and the lower end surface 2b. The lower steel pipe column 1A is erected vertically from, for example, a concrete foundation 1C, and the upper steel pipe column 1B is fixed to the lower steel pipe column 1A by a temporary fixing jig 5. After welding the lower steel pipe column 1A and the upper steel pipe column 1B along the groove 2c, the temporary fixing jig 5 is removed from the steel pipe column 1. Note that, although an example in which the lower steel pipe column 1A is erected from a concrete foundation 1C has been shown, this is not limited to this, and for example, the lower steel pipe column 1A may be connected to a steel pipe column of a lower floor via a column joint.

The lower steel pipe column 1A and the upper steel pipe column 1B are rectangular steel pipe columns, and are composed of polygonal steel pipes formed by four flat sections and four curved sections. The four flat sections have a front surface 3A, both side surfaces 3B and 3C adjacent to the front surface 3A, and a back surface 3D adjacent to both side surfaces 3B and 3C and parallel to the front surface 3A, and the front surface 3A, both side surfaces 3B and 3C, and the back surface 3D are formed into a rectangular cross-sectional shape that is continuous via four curved surfaces 3E.

Multiple (four in this case) protrusions (also called erection pieces) 4A, 4B are welded to predetermined positions on the flat portions of the outer circumferential surfaces of the lower steel pipe column 1A and the upper steel pipe column 1B, i.e., the front 3A, both sides 3B, 3C, and back 3D. These protrusions 4A, 4B are provided to temporarily fix the lower steel pipe column 1A and the upper steel pipe column 1B to each other. Temporary fixing jigs 5 are attached to the two protrusions 4A, 4B arranged vertically, and the lower steel pipe column 1A and the upper steel pipe column 1B are in a temporarily fixed state.

The temporary fixing jig 5 extends in the vertical direction, and its upper end is fastened to the protruding piece 4A using a bolt 6 or the like, and its lower end is fastened to the protruding piece 4B using a bolt 6 or the like. Although detailed explanation of the temporary fixing jig 5 is omitted here, it may be configured so that the distance between the two protruding pieces 4A and 4B arranged vertically can be adjusted. This makes it possible to adjust the gap between the lower steel pipe column 1A and the upper steel pipe column 1B arranged vertically, and to adjust the inclination of the upper steel pipe column 1B arranged on the upper side. The temporary fixing jig 5 is removed from the protruding pieces 4A and 4B when the welding of the butt portion 2 between the lower steel pipe column 1A and the upper steel pipe column 1B is completed, or even if the welding of the butt portion 2 is in progress, when the joint strength between the lower steel pipe column 1A and the upper steel pipe column 1B becomes large enough to support the building under construction.

Next, the welding of the butt portion 2 of the steel pipe column 1 temporarily fixed in this manner will be described with reference to FIG. 2. FIG. 2(a) is an explanatory diagram showing the schematic configuration of the welding process, and FIG. 2(b) is a schematic horizontal cross-sectional view of a steel pipe column. In FIG. 2, the lower steel pipe column 1A and the upper steel pipe column 1B have, in the horizontal cross-section, a front surface 3A, both side surfaces 3B and 3C adjacent to the front surface 3A, and a back surface 3D adjacent to both side surfaces 3B and 3C and parallel to the front surface 3A, and the front surface 3A, both side surfaces 3B and 3C, and the back surface 3D are formed into a cross-sectional rectangular shape that is continuous via four curved surfaces 3E.

Now, referring to FIG. 2(b), the horizontal cross section of the steel pipe column 1A (1B) will be described. As described above, the steel pipe column 1A (1B) is composed of a polygonal steel pipe formed by four flat parts and four curved parts, and the entire circumference is formed by the front surface 3A, both side surfaces 3B and 3C, the back surface 3D, and four curved surfaces 3E. The front surface 3A forms a straight line portion L1, the side surface 3B forms a straight line portion L2, the back surface 3D forms a straight line portion L3, and the side surface 3C forms a straight line portion L4. In addition, the four curved surfaces 3E form arc-shaped corner portions R1, R2, R3, and R4. As will be described in detail later, the corner members that form the arc-shaped corner portions of the jig body have a shape that includes at least a part of the arc-shaped corner portions and the straight lines.

In FIG. 2(a), a pair of rails 31 are fixed to the lower steel pipe column 1A of the steel pipe column 1 so as to sandwich the lower steel pipe column 1A at a predetermined interval in order to weld the butt portion 2 of the steel pipe column 1 with a robot arm 40 (40A, 40B). The rails 31 are linear guide rails, and a carriage (slider) 32 is attached to the rails 31, and the carriage 32 is freely movable along the rails 31 by a motor (not shown).

Although not shown in FIG. 2(a), as shown in FIG. 9 described later, a reinforcing member 72 is attached below the rail 31 along the rail 31, and the rail 31 is supported by a pair of support beams 73, 73 via the reinforcing member 72 so as to intersect with the pair of support beams 73, 73. The pair of support beams 73, 73 are fixed to the steel pipe column so as to sandwich the steel pipe column, and when teaching the operation of the robot arm 40, they are fixed to the fixed column 12 so as to sandwich the fixed column 12.

A pair of welding robot arms 40 (40A, 40B) are mounted on the carts 32, 32 so that they can move. A control device (not shown) controls the movement of the cart 32, the drive control of the robot arm 40 described below, and welding according to the welding conditions using a torch 50 attached to the tip of the robot arm 40. The robot arm 40 is a multi-joint robot that rotates on six axes, and is a welding robot arm connected to a welding machine. In FIG. 2, the robot arms 40A, 40B are mounted on each rail 31.

The robot arm 40 comprises a base attached to the cart 32, and a swivel base 41 that is placed on the base and rotates relative to the base. A lower arm 42 is pivotally attached to the swivel base 41. A joint 43 is pivotally attached to the tip of the lower arm 42. An upper arm 44 is attached to the joint 43 so as to be rotatable around an axis in the longitudinal direction. The robot arm 40A is configured to perform welding in the welding area A, and the robot arm 40B is configured to perform welding in the welding area B.

Furthermore, a support arm 45 is attached to the tip of the upper arm 44, which supports a torch 50 of a welding machine that serves as an end effector. A cable 91 (see FIG. 9, described later) that feeds welding wire is connected to the torch 50 of the support arm 45 and the upper arm 44, and the base end of the cable is connected to a feeding device (not shown) that feeds the welding wire.

The movement path (welding path) of the torch 50 of the robot arm 40 divides the welding line of the groove 2c, which rotates in the circumferential direction, into multiple welding sections 1L, 1R, 2L, and 2R. In this embodiment, the welding line of the groove 2c is divided into four sections sandwiched between the erection pieces 4A and 4B. The division of the welding line is not limited to the above-mentioned welding line, and the flat part of the column may not be parallel to the rail, but may be arranged at an angle of approximately 45 degrees. In addition, although the welding line of the groove 2c is divided into four welding sections, the worker may divide the welding section into an appropriate number depending on the ease of welding, changes in the gap, etc.

Next, the teaching jig 10 for moving the welding torch of the robot arm 40 along the butt joint 2 between the pillars will be described with reference to Figures 3 to 6. Figure 3 is a plan view of the teaching jig 10, Figure 4 is an elevational view taken along line A-A in Figure 3, Figure 5 is a perspective view showing the jig body of the teaching jig, and Figure 6 is a perspective view of an exploded state showing one corner member of the jig body in Figure 5.

The lower steel pipe column 1A and the upper steel pipe column 1B are composed of polygonal steel pipes formed by four flat portions and four curved portions as described above. That is, in a cross section perpendicular to the axial direction, the steel pipe column 1 has an outer surface in a polygonal shape with a front surface 3A, both side surfaces 3B, 3C, a number of straight line portions L1 to L4 corresponding to a back surface 3D adjacent to both side surfaces 3B, 3C and parallel to the front surface 3A, and arc-shaped corner portions R1 to R4 connecting the straight line portions, as shown in FIG. 2(b).

The teaching jig 10 includes a frame-shaped jig body 11 that corresponds to the outer peripheral surface of the steel pipe column 1 described above, and a fixed column 12 that is located at the center of the jig body 11 and that detachably fixes the jig body 11. The jig body 11 is composed of straight members 15 and corner members 20. In this embodiment, the steel pipe column 1 is a polygonal rectangular steel pipe, so the jig body 11 is composed of four straight members 15 and four corner members 20 that connect the straight members 15 together, the number of which corresponds to the shape of the polygon. These eight members form a frame shape that is the same as the outer periphery of the steel pipe column 1.

More specifically, the straight member 15 is formed, for example, from a metal plate material containing a soft magnetic material, and includes a flat straight member 16 that forms part of the straight portions L1 to L4, and a support member 17 that is joined to and supports the straight member 16. The corner member 20 is also formed from a metal plate material containing a soft magnetic material, and includes an arc-shaped portion 21 having the same radius of curvature as the four curved surfaces 3E (of the arc-shaped corner portions R1 to R4) of the steel pipe column 1, and linear linear portions 22, 22 that extend a predetermined length from both ends of the arc-shaped portion 21. Therefore, at each end of the corner member 20, a portion corresponding to a part of the straight portions L1 to L4 of the steel pipe column 1 is formed as the linear portion 22, 22. Here, the type of the soft magnetic material is not particularly limited as long as it includes a material that is attracted to a magnet, such as an iron-based material, and for example, a resin material may have soft magnetic powder dispersed therein. The straight member 15 and the corner member 20 may be made of a soft magnetic material, as long as at least the parts that are connected by the magnets described below are made of a soft magnetic material.

The arc-shaped portion 21 is formed as a quarter arc, and since the interior angle forming the arc is 90 degrees, the linear portions 22, 22 extend perpendicularly. The four corner members 20 have the same cross-sectional shape as the straight members 16 of the four straight members 15. That is, as shown in Fig. 6, the thickness t and height h of the linear portions 22 of the corner members 20 are equal to the thickness t and height h of the straight members 16 of the straight members 15.

As shown in FIG. 5 etc., the corner member 20 has linear portions 22, 22 formed continuously at both ends of the arc-shaped portion 21, and each end of the corner member 20 forms a part of the straight portion L1 to L4 that constitutes the four flat portions (front surface 3A, both sides 3B, 3C, and back surface 3D) of the steel pipe column 1. That is, as shown in FIG. 2(b), the corner member 20 is formed so as to straddle, for example, the straight portion L1 constituted by the front surface 3A and the straight portion L2 constituted by the side surface 3B, and the linear portions 22, 22 form a part of the straight portions L1, L2 of the front surface 3A and the side surface 3B.

The four straight members 15 and the four corner members 20 of the teaching jig 10 are configured to be attracted by permanent magnets 25. In this embodiment, as shown in FIG. 6, the permanent magnets 25 are fixed to both ends (end faces) of the four corner members 20 by countersunk screws 26 or the like. The permanent magnets 25 are made of a hard magnetic material such as samarium cobalt or neodymium, and firmly connect and fix the four straight members 15 and the four corner members 20. This allows the straight members 15 and the corner members 20 to be reliably connected by a simple operation using the permanent magnets 25. The permanent magnets 25 may be fixed to the four straight members 15. In this embodiment, the permanent magnets 25 are exemplified, but the straight members 15 and the corner members 20 may be connected by an electromagnet, or they may be connected and fixed using both the permanent magnets 25 and the electromagnets.

As shown in FIG. 4, the fixed column 12 fixes the jig body 11 of the teaching jig 10, and has a base 13A extending horizontally and a column portion 13B extending vertically from the base 13A. In addition, an arm portion 14 extending horizontally in four orthogonal directions is joined to the column portion 13B. The four supports 17 of the jig body 11 are fixed to the four arms 14 via relay plates 18, so that the jig body 11 can be freely attached and detached to the fixed column 12. The relay plate 18 has a long hole for attachment adjustment formed in the direction in which the arm portion 14 extends, so that jig bodies 11 of different sizes can be attached to the fixed column 12.

Next, in the jig body 11 shown in the above embodiment, an example is shown in which it is composed of four straight members 15 in the first set and four corner members 20 in the second set, but the jig body 11 of the teaching jig has multiple types of sets of the first set and the second set in addition to the four straight members 15 in the first set and the four corner members 20 in the second set. Specifically, the first set has multiple types of sets with different lengths of the straight members 16 corresponding to the straight portions L1 to L4 of the straight members 15, and the second set has multiple types of sets with different radii of curvature of the arc-shaped portions 21 corresponding to the arc-shaped corner portions R1 to R4 and different lengths of the linear portions 22, 22. Here, the reason why the second set has multiple types of sets with different radii of curvature of the arc-shaped portions 21 is because the radius of curvature of the arc-shaped corner portion of the actual steel pipe column to be welded depends on the plate thickness (wall thickness) of the steel pipe column. For example, in the case of a steel pipe column made of press-formed rectangular steel pipe (BCP), the relationship r = 3.5t (r: radius of curvature, t: plate thickness) is satisfied, and the shape of such a steel pipe column can be reproduced using the teaching tool described below.

These multiple types of sets are described below with reference to Figures 7 and 8. Figure 7 is a plan view of multiple types of straight members of the teaching jig, and Figure 8 is a plan view of multiple types of corner members of the teaching jig. Note that Figures 7 and 8 are drawn to different scales.

The straight members 15A to 15I of each first set shown in FIG. 7 are of multiple types with different longitudinal lengths of the straight members 16, and the support members 17 fixed to the fixed columns 12 have the same shape. For example, the length of the straight members 16 is 254 mm in (a), 304 mm in (b), 354 mm in (c), 404 mm in (d), 454 mm in (e), 504 mm in (f), 554 mm in (g), 604 mm in (h), and 654 mm in (i).

Each of the second set of corner members 20A to 20G shown in FIG. 8 is formed of an arc-shaped portion 21 and linear portions 22, 22. For example, the corner members 20A to 20G each have a different radius of curvature of the arc-shaped portion 21 and different lengths of the linear portions 22, 22. Specifically, in (a), the arc-shaped portion 21 is formed of a circular arc with a radius of curvature of 140 mm, and the length of the linear portions 22, 22 is set to 30 mm.

Furthermore, in FIG. 8(b), the radius of curvature of the arc-shaped portion 21 is 126 mm, and the length of the linear portions 22, 22 is 44 mm; in (c), the radius of curvature of the arc-shaped portion 21 is 112 mm, and the length of the linear portions 22, 22 is 58 mm; in (d), the radius of curvature of the arc-shaped portion 21 is 98 mm, and the length of the linear portions 22, 22 is 72 mm; in (e), the radius of curvature of the arc-shaped portion 21 is 87.5 mm, and the length of the linear portions 22, 22 is 82.5 mm; in (f), the radius of curvature of the arc-shaped portion 21 is 77 mm, and the length of the linear portions 22, 22 is 93 mm; and in (g), the radius of curvature of the arc-shaped portion 21 is 66.5 mm, and the length of the linear portions 22, 22 is 103.5 mm.

In this embodiment, by selecting and combining these multiple types of first set straight members 15A-15I and second set corner members 20A-20G, it is possible to create a teaching jig 10 that can accommodate steel pipe columns 1 of a wide variety of sizes (600-1000 mm). Note that by changing not only the radius of curvature of the arc-shaped portion 21 but also the length of the arc of the arc-shaped portion 21, it is possible to accommodate a wide variety of polygonal steel pipes.

A teaching method using the teaching jig 10 of this embodiment configured as described above will be described below.
First, as described above, when welding the butt portion 2 of columns consisting of steel pipe columns 1 arranged vertically, the robot arms 40A and 40B mounted on the rail 31 shown in Fig. 2 are used, and the torch 50 of the robot arm is moved along the groove 2c of the steel pipe column 1 to set a welding path. In the example of Fig. 2, the robot arm 40A is set to share the area of the welding range A, and the robot arm 40B is set to share the area of the welding range B.

In this embodiment, there is no need to perform teaching work on a steel pipe column at the construction site. For example, as shown in FIG. 9, the robot arms 40A and 40B mounted on rails 31 are installed in a work site different from the construction site. Specifically, the robot arms 40A and 40B are installed so that they are in the same positional relationship with the steel pipe column to be welded as they are at the construction site. As shown in FIG. 9, a teaching tool 10 is fixed to the fixed column 12 of the robot arms 40A and 40B installed in this way, and using a teaching pendant (not shown) or the like, the worker teaches the robot arms 40A and 40B the operation of the robot arms 40A and 40B along the welding path.

Specifically, the required size is selected from the multiple types of first set straight members 15 and multiple types of second set corner members 20 shown in Figures 7 and 8 according to the size of the steel pipe column 1 to be welded. Then, as shown in Figure 10, the four selected first set straight members 15 and the four second set corner members 20 are connected by attracting them at their end faces with permanent magnets 25 to create a frame-shaped jig body 11. The created jig body 11 is fixed to the arm portion 14 of the fixed column 12 to form a teaching jig 10 of a predetermined size. Specifically, the insertion hole of the support material 17 is aligned with the long hole formed in the relay plate 18 and fastened with bolts and nuts, and the long hole of the relay plate 18 is aligned with the long hole of the arm portion 14 and fastened with bolts and nuts to fix the jig body 11 to the fixed column 12.

The fabricated jig body 11, like the steel pipe column 1, has a polygonal outer surface with multiple straight sections and arc-shaped corners connecting the straight sections, and is suitable for the steel pipe column 1 to be welded. In the teaching method of this embodiment, the teaching jig 10 is fixed on a horizontal base 19 at a work site or the like, and the jig body 11 is treated as the butt portion 2 of the column, and the tip of the torch 50 is brought into contact with the jig body 11 at intervals along a path along the outer circumferential surface of the jig body 11 to teach the operation of the welding robot arm.

Specifically, as shown in FIG. 10, the probe (tip) of the robot arm 40 is brought into contact with the straight material 16 of the straight member 15 constituting the jig body 11 and the linear portion 22 of the corner member 20 at a distance. Specifically, the probe is brought into contact with positions P1 and P2 of the linear portion 22, and the linear portion 22 is identified as a path at two points. Furthermore, the probe is brought into contact with positions P3, P4, and P5 of the adjacent arc-shaped portion 21, and the arc-shaped portion 21 is identified as a path at three points. Furthermore, the probe is brought into contact with positions P6 and P7 of the adjacent linear portion 22, and the linear portion 22 is identified as a path at two points. In this way, the operation of the robot arm 40 can be taught on a path along the outer peripheral surface of the jig body 11. In this way, the operation of the robot arm 40 can be taught while the probe is brought into contact with positions P1 to P16 in order.

In this way, the jig body 11 of the teaching jig 10 can be used to teach the welding areas A and B as a path, and a path along the entire circumference of the outer periphery of the jig body 11 can be taught. In this way, by using the teaching jig 10 of this embodiment, the tip of the welding robot arm 40 can be brought into contact with a gap, and the operation of the robot arm 40 can be easily taught not only at a construction site but also at a work site or the like.

Next, other embodiments of the teaching jig 10 will be described. For example, the teaching jig 10A shown in Figures 11 and 12 is made by combining the straight member 15I in Figure 7 and the corner member 20G in Figure 8. A teaching jig for teaching the operation of a welding robot arm can be made by easily combining multiple types of teaching jigs, such as the teaching jig 10 corresponding to the small steel pipe column shown in Figures 3 to 5 from the teaching jig 10A corresponding to the large steel pipe column shown in Figure 11.

The jig body 11A of the teaching jig 10A of this embodiment is formed with a larger outer shape than the jig body 11 of the above-mentioned embodiment. Therefore, the relay plate 18A connecting the support material 17 of the straight member 15 constituting the jig body 11A and the arm portion 14 of the fixed column 12 is formed longer than the relay plate 18 shown in FIG. 5. Similarly, in this embodiment, the long hole formed in the relay plate 18A is aligned with the insertion hole of the support material 17 and fastened with a bolt nut, and the long hole of the relay plate 18 is aligned with the long hole of the arm portion 14 and fastened with a bolt nut to fix the jig body 11A to the fixed column 12.

In this way, even in the case of a large steel pipe column 1 with a large external shape, the operation of the welding robot arm that moves the tip of the robot arm 40 can be easily taught not only at construction sites but also at work sites, etc., using a large jig body 11A.

As described above, according to this embodiment, the first set consisting of the straight members 15 and the second set consisting of the corner members 20 are composed of multiple types of sets, so that the jig body 11 can be produced by selecting from multiple types of straight members 15 and corner members 20 to match the steel pipe column 1. As a result, even if a teaching steel pipe column according to the size to be actually welded is not prepared, the operation of the robot arm 40 can be taught in advance inexpensively and easily using the teaching jig 10 produced according to the size of the steel pipe column 1.

Furthermore, in this embodiment, the connecting portions connecting the first set of straight members 15 and the second set of corner members 20 are formed in straight line portions L1-L4 offset from both ends of the arc-shaped corner portions R1-R4, and both ends of the arc-shaped corner portions R1-R4 are formed midway through the corner member 20. As a result, it is possible to more accurately identify the positions of both ends of the arc-shaped corner portions R1-R4 for the fabricated jig body 11. This makes it possible to more accurately teach the operation of the robot arm 40.

Next, referring to FIG. 13, another embodiment of the teaching jig will be described. FIG. 13 is a perspective view of the main part of the jig body of another embodiment of the teaching jig. In FIG. 13, the teaching jig is characterized by the corner member 20 and the straight member 15 that constitute the jig body 11B.

In the embodiment described above, the straight member 15 and corner member 20 constituting the jig body 11 are made of a soft magnetic material, and a permanent magnet 25 is attached to at least one end face where the straight member 15 and the corner member 20 are connected. In contrast, in the jig body 11B of this teaching jig, a backing plate 27 is fixed by welding or the like to either the straight member or the corner member, which abuts against the inner surface of the other member located inside the polygon (rectangle).

In this embodiment, a backing plate 27 with a width narrower than the vertical width of the corner member 20 is fixed to the inner peripheral surface of the corner member 20 so as to protrude from the end face of the corner member 20 toward the straight member 15. The backing plate 27 has a through hole 27a formed therein through which a connecting bolt 28 for connecting to the straight member 15 is inserted. Meanwhile, the straight member 16 of the straight member 15 has a through hole 16a formed therein through which the connecting bolt 28 is inserted together with the through hole 27a of the backing plate 27.

In this way, with the backing plate 27 and the straight member 15 overlapped, the connecting bolt 28 is inserted through the through holes 27a, 16a formed in the backing plate 27 and the straight member 15, and the straight member 15 and the corner member 20 are connected. More specifically, the straight member 15 and the corner member 20 can be connected by abutting the end face of the straight member 15 against the end face of the corner member 20, inserting the connecting bolt 28 through the through hole 16a of the straight member 15, and tightening the nut through the through hole 27a of the backing plate 27. In this embodiment, the connection state of the straight member 15 and the corner member 20 constituting the jig body 11B can be stabilized. Note that the backing plate 27 is fixed to the corner member 20, but it may be configured to be fixed to the straight member 15.

In this embodiment, the straight member 15 and the corner member 20 do not necessarily need to be made of a soft magnetic material, but may be made of a soft magnetic material. In this case, a permanent magnet 25 may be used in combination with the straight member 15 and the corner member 20.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various design changes can be made without departing from the spirit of the present invention as described in the claims.

For example, in the teaching jig 10, the jig body 11 and the fixed column 12 are fixed to each other, and an example has been shown in which the arm portion 14 and the support material 17 are fixed to each other via the relay plate 18. However, the support material 17 may be extended further to the inner circumference and the arm portion 14 may be extended further to the outer circumference, thereby omitting the relay plate and directly fixing the support material 17 to the arm portion 14.

1: Steel pipe column, 1A: Lower steel pipe column, 1B: Upper steel pipe column, 2: Butt joint, 3A: Front, 3B, 3C: Both sides, 3D: Back, 3E: Curved surface, 10, 10A: Teaching jig, 11, 11A, 11B: Jig body, 12: Fixed column, 15, 15A-15I: Straight member, 16: Straight member, 17: Support member, 20, 20A-20G: Corner member, 21: Arc-shaped portion, 22: Linear portion, 25: Permanent magnet, 27: Backing plate, 40, 40A, 40B: (Welding) robot arm, L1-L4: Straight portion, R1-R4: Arc-shaped corner portion

Claims (6)

A teaching tool for teaching the operation of a welding robot arm used for welding a butt portion of columns made of steel pipe columns arranged above and below, which moves the tip of the welding robot arm along the butt portion,
The steel pipe column has a polygonal outer surface having a plurality of straight line portions and arc-shaped corner portions connecting the straight line portions in a cross section perpendicular to the axial direction,
the teaching jig has a straight member forming at least a part of the straight portion, and a corner member forming the arc-shaped corner portion and connecting the straight members to each other,
the straight members and the corner members are configured as a first set of straight members, the number of which corresponds to the shape of the polygon, and a second set of corner members, the number of which corresponds to the shape of the polygon,
The first set and the second set are configured such that a jig body corresponding to the steel pipe column is produced by connecting the straight member of the first set and the corner member of the second set,
the first set includes a plurality of sets having different lengths of a portion of the straight member corresponding to the straight portion,
The second set includes a plurality of sets having different radii of curvature of the portions corresponding to the arcuate corners. The teaching tool according to claim 1, characterized in that each end of the corner member forms part of the straight portion. The teaching tool according to claim 1 or 2, characterized in that at least one of the parts where the straight member and the corner member are connected is made of a soft magnetic material, and a magnet is attached to the other part. a backing plate is fixed to one of the straight member and the corner member, the backing plate being in contact with an inner surface of the other member that is located on the inside of the polygon;
The teaching tool described in any one of claims 1 to 3, characterized in that the backing plate and the other member are formed with an insertion hole through which a connecting bolt is inserted when the backing plate and the other member are stacked so that the straight member and the corner member are connected. The teaching jig includes a fixing column for fixing the jig body,
The teaching tool according to any one of claims 1 to 4, characterized in that, when the straight members and the corner members are connected, each of the straight members is removably fixed to the fixed column. A teaching method using the teaching jig according to any one of claims 1 to 5,
Selecting the first and second sets according to the shape of the steel pipe column from a plurality of types of the first sets and a plurality of types of the second sets,
The jig body corresponding to the steel pipe column is produced using the selected first and second sets,
a teaching method for teaching the operation of the welding robot arm by treating the jig body as the butt joint between the pillars and contacting the tip of the welding robot arm with a gap in between the jig body and a path along the outer peripheral surface of the jig body.

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