JP2748835B2 - Automatic arc welding equipment for rebar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rebar automatic arc welding apparatus for automatically rebar welding using a high-speed rotating arc welding method.

[0002]

2. Description of the Related Art Conventionally, in arc welding for welding a reinforcing bar, a pair of reinforcing bars are supported by providing a predetermined groove gap between joining end faces thereof, and a part of the outer periphery of the groove portion is used for welding. The method has been practiced in such a way that a welding torch is horizontally reciprocated from one end to the other within a groove portion in an atmosphere of a shielding gas and a welding metal is provided in multiple layers under a shield gas atmosphere.

However, in the conventional method, since the welding is performed without rotating the torch, there are the following problems. Since the surface of the weld bead becomes convex (or the degree of depression is insufficient), poor fusion is likely to occur at the time of welding in the next pass.
Further, the penetration is concentrated at the center, and the penetration into the groove side wall is insufficient, so that poor fusion is likely to occur. This will be described below with reference to FIG. Since the penetration is concentrated at the center, the sectional shape of the weld bead 100 has a downwardly convex shape as shown in the figure. Also, the surface of the weld bead is convex. Further, the penetration P1 into the groove side wall 101 is also small. Therefore, at the time of welding in the next pass indicated by the dotted line, poor fusion is likely to occur in both side portions 102 of the bead laminated portion. If there is variation in the groove width, the perpendicularity of the groove cut surface, the degree of adhesion of the backing material, etc., the amount of weld metal required to fill the groove changes. Therefore, when the automatic welding is performed with this constant, the amount of the deposited metal may be excessive or insufficient, or a welding defect may be generated due to an inappropriate width of the reciprocating motion of the welding torch.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional method.
It is to solve the following two problems. (1) The bead shape is improved by high-speed rotation of the arc,
Prevents welding defects. (2) By controlling the position of the repetition point of the reciprocating movement of the welding torch and controlling the automatic stop of the welding, it is possible to automate the welding of the rebar joint and save labor.

[0005]

SUMMARY OF THE INVENTION An automatic arc welding apparatus for a reinforcing bar according to the present invention includes a chamber jig attached to a welding portion of a pair of reinforcing bars as a material to be welded, and a welding machine body for performing arc welding of the reinforcing bar. And a welding control device for automatically controlling the welding machine body, wherein the chamber jig is a jig member for clamping a pair of rebars at a predetermined interval, and a welding backing material for the welding backing material. A mechanism for supporting a part of the outer periphery of the torch, and a nozzle mechanism for ejecting a shielding gas to the welding groove portion, the welding machine body, a welding torch for rotating the welding wire at the tip of the torch at high speed, and the welding torch Y-axis slide mechanism for moving in the torch axis direction, X-axis slide mechanism for moving the welding torch in a direction perpendicular to the torch axis and parallel to the joint end face of the reinforcing bar, and adjusting the welding torch in the groove width direction And adjustment axes ability of the welding torch X
The welding control device includes a torch height control unit using an arc sensor, a storage unit that stores information on a cross-sectional shape of a reinforcing bar, and a welding unit that stores information on a cross-sectional shape of a reinforcing bar. By giving the torch height detected by the position detector, the position of the repetitive point of the reciprocating movement of the welding torch in the X-axis direction is calculated according to the cross-sectional shape of the reinforcing bar stored in the storage means. Control means for repetitively moving the welding torch by means of a shaft slide mechanism, and welding by means of the torch height detected by a position detector in the Y-axis direction, in accordance with the cross-sectional shape of the reinforcing bar stored in the storage means. And a control means for calculating a height of the welding torch to be terminated in the Y-axis direction and automatically stopping welding.

[0006]

The chamber jig clamps a pair of rebars while maintaining a predetermined groove gap between their joint end faces,
A part of the outer periphery of the groove is covered with a welding backing material to prevent leakage of the weld metal. Further, a shield gas is blown into the groove from the nozzle mechanism, and arc welding of the reinforcing bar is performed in a shield gas atmosphere.

In welding the reinforcing bars, the arc is rotated at a high speed by a high-speed welding torch and reciprocated in the X-axis direction from the bottom of the groove, and the layers are sequentially laminated, and the height of the welding torch is adjusted to the top of the reinforcing bar. The welding is automatically terminated at the position where has been reached. Here, the positions of the welding torch in the X-axis and Y-axis directions are detected by an X-axis position detector and a Y-axis position detector, respectively. Further, the welding control device controls the torch height by the arc sensor. Further, the arithmetic unit of the welding control device gives the torch height detected by the Y-axis position detector, so that the welding torch reciprocates in the X-axis direction according to the cross-sectional shape of the reinforcing bar stored in the storage device. The position of the repetition point and the height in the Y-axis direction at which welding is completed (the position of the welding end point) are calculated. Therefore, the welding torch is X
When the repetition point of the axial reciprocation is reached, the driving direction of the X-axis slide mechanism is reversed, and the moving direction of the welding torch is reversed. Then, when the welding end point is reached, the welding is automatically stopped.

[0008]

FIG. 1 is a schematic diagram of an automatic arc welding apparatus for a reinforcing bar according to an embodiment of the present invention. 2 is a partial sectional front view of a chamber jig attached to a welded portion of a reinforcing bar, and FIG. 3 is a sectional view taken along line AA of FIG. The present welding apparatus includes a chamber jig 10 attached to a welding portion of the reinforcing bars 1 and 1.
And a welding machine main body 30 that is supported on one of the rebars 1 by a clamp device 31 in a cantilever manner.
A welding control device 50 shown in FIG.
And a welding power source (not shown) are connected to the chamber jig 1
0 is connected to a shielding gas cylinder and a cooling water supply device (neither is shown).

The welding machine main body 30 includes a support block 32 having a built-in rotary drive mechanism (not shown) for a high-speed rotary welding torch (hereinafter, referred to as a welding torch) 3.
2 is connected to the Y-axis support block 34 via a Y-axis slide mechanism 33, and the X-axis support block 36 is connected to the Y-axis support block 34 via an X-axis slide mechanism 35.
And a clamping device 31 to which the X-axis support block 36 is attached.
2 is configured to be slidable in the groove width direction (axial direction of the rebar) by the fine adjustment screw 40 with respect to the side arm 39 having the Y-axis slide mechanism 33. The X-axis and Y-axis slide mechanisms 35 and 33 are based on a well-known screw mechanism, and as shown in FIG.
An axis position detector 38 is provided. Further, the manual fine adjustment screw 40 may be constituted by an automatic slide mechanism similar to the X-axis and Y-axis slide mechanisms 35 and 33 so that automatic groove copying by an arc sensor can be performed. In the figure, reference numeral 60 denotes an operation lever which can open and close the clamp device 31 in a one-touch manner by a link mechanism or a cam mechanism, 61 denotes a conduit cable, 62 denotes a cable fixing jig, 63 denotes an operation pendant, and 64 denotes a handle.

As shown in FIG. 2, a pair of rebars 1, 1 to be welded are cut perpendicularly to the axial direction, and joint end faces 1a,
1a is formed, and a groove portion 2 having a predetermined gap is provided between the joining end surfaces 1a, 1a, and is horizontally arranged. In the case of a vertical reinforcing bar, the groove 2 is formed horizontally or obliquely with respect to the reinforcing bar axis. When the groove 2 is provided obliquely, it is necessary to incline the axis of the welding torch 3. The groove shape is not limited to such an I-shape.

The chamber jig 10 has a backing material 11 having a U-shaped cross section inside, and the backing material 11 covers at least the lower half of the outer periphery of the groove 2. Backing material 11
Is made of copper or a ceramic material and is inserted from above into a groove 13 provided in a U-shaped inner surface of a lower receiving portion 12 of a chamber jig 10 formed of a split mold by two jig members. The lower receiving portion 12 is provided with a thumbscrew 14, which pushes up the backing material 11 at its tip, and attaches the backing material 11 to the outer surface of the reinforcing bars 1, 1.
Lightly touch the inner surface of

The upper holding portion 16 of the chamber jig 10 is joined to the lower receiving portion 12 at one end of a separation surface by a hinge 17, and a side surface opposite to the two members 16, 12 is provided with a ball catching mechanism or the like. A latch 18 and a receiving ball 19 are attached. The upper holding portion 16 also has a rectangular insertion opening 20 into which the welding torch 3 is inserted, and a groove portion 2.
Nozzle mechanism 2 for blowing shield gas into
1 and 21 are provided. The nozzle holes 23 of the respective nozzle tubes 22 constituting the nozzle mechanisms 21 and 21 are disposed slightly left and right facing each other obliquely downward, and the shield gas ejected from the nozzle holes 23 is passed through the passage 24 to the chamber chamber 25 above the groove 2. I try to guide. The shield gas from the left and right direction, which has been rectified to some extent in the passage 24, is supplied to the chamber 25.
Collides at the central portion of the groove, and is blown into the groove portion 2 as downward rectification. Note that the chamber jig 10 further includes a cooling water pipe for circulating cooling water,
It is not shown here.

On both left and right sides of the chamber jig 10, clamp portions 26, 26 of the rebars 1, 1 are provided continuously. The clamp portions 26, 26 are split types, and each of the lower clamp portions 27 integrally connected to the lower receiving portion 12 is
By tightening 8 with bolts 29, both rebars 1 and 1 are clamped.

Next, the welding torch 3 comprises an electrode nozzle 4 and
The welding tip 5 is formed of a contact tip in which the insertion hole of the welding wire 6 is eccentric. In addition, the welding torch 3 is provided with a rotation drive mechanism (not shown) for providing rotation about the torch axis.
And a Y-axis slide mechanism 33 that provides Y-axis movement in the torch axis direction, and an X-axis slide mechanism 35 that provides X-axis reciprocal movement in a direction perpendicular to the torch axis and parallel to the reinforcing bar joining end faces 1a, 1a.
And a fine adjustment shaft 40 in the groove width direction for finely adjusting the welding torch 3 in the groove width direction. Therefore, the tip of the welding wire 6 performs a circular motion by the rotation of the welding torch 3, and the arc can be rotated at a high speed.
While the arc is rotated at a high speed, the welding torch 3 is inverted around the groove 2 by reciprocating movement in the X-axis direction and movement in the Y-axis direction as shown in FIG. Laminate together and perform multi-layer welding.

When welding the rebars 1 and 1, first, the chamber jig 10 configured as described above is set. First, the upper holding part 16 of the chamber jig 10 is used.
With the left and right clamp portions 26, 26 open, the groove 1
3, the lower backing portion 12 and the lower clamp portions 27, 27 are applied to the reinforcing bars 1, 1 from below, and at this time, the reinforcing bars 11 are provided on the inner surface of the backing member 11 at predetermined intervals. Confirm that the joint end faces 1a, 1a are positioned. Then, the upper clamps 28, 28 are tightened, and the reinforcing bars 1, 1 are clamped. Thereafter, the upper holding portion 16 of the chamber jig 10 is closed, and the backing material 11 is pushed up and set by the thumb screw 14 so that the inner surface of the backing material 11 lightly touches the reinforcing bars 1 and 1.

After the setting of the chamber jig 10, a shield gas is supplied to the chamber jig 10 from the nozzle mechanisms 21 and 21 to make the inside of the groove 2 a shield gas atmosphere. Carbon dioxide, a mixed gas of argon and carbon dioxide, or the like is used as the shielding gas. Next, the welding torch 3 is inserted from the insertion opening 20 of the chamber jig 10 and set at the center position of the groove 2 in the width direction, and then the arc is started from the groove bottom. When an insulating backing material such as ceramics is used, before the arc start, an iron powder 41 is sprayed on the bottom surface of the backing material 11 as shown in FIG.
First, an arc is generated between the welding wire 6 and the welding wire 6.

FIG. 5 is a diagram showing a reinforcing bar welding lamination pattern by a rotating arc. In the drawing, reference numeral 42 denotes a movement trajectory of the welding torch 3, reference numeral 43 denotes a welding start point, reference numeral 44 denotes a welding end point, and reference numeral 45 denotes a torch repetition point. FIG. 4 is a block diagram of the welding control device. The welding control device 50 stores the rebar cross-sectional shape information, sets the necessary rebar cross-sectional shape information in a calculator 52 according to a command, and detects the Y-axis position of the Y-axis slide mechanism 33. By giving the Y-axis position (torch height) Yp detected by the detector 38, the X-axis inversion position (torch repetition point 45) in each pass in FIG. ) And a comparator 53 that calculates the position of the welding end point 44, a comparator 53 that sends an inversion command to the X-axis drive control circuit 54, and welding that automatically stops welding based on a welding end determination command from the calculator 52. And a sequence control circuit 55. The inversion position XPO calculated by the calculator 52 is given to the comparator 53, and the X-axis position XP detected by the X-axis position detector 37 of the X-axis slide mechanism 35 is sent and the two values match. The comparator 53
Outputs an inversion command to the X-axis drive control circuit 54. The X-axis drive control circuit 54 controls to reverse the drive direction of the X-axis slide mechanism 35 according to the inversion command. The torch height of the welding torch 3 is controlled by a known arc sensor circuit so that the welding current or the torch height is kept constant.

The control operation of the welding control device 50 is as follows. From the welding start point 43 at the groove bottom (this position is set based on the rebar cross-sectional shape stored in the storage device 51), the arc is started at a high speed by the welding torch 3 and the Y-axis position detector 38 Detect the torch height YP. On the other hand, an arc sensor circuit (not shown) moves the welding torch 3 upward or downward by the Y-axis slide mechanism 33 so as to maintain the reference current value by detecting the welding current, for example. Further, the computing unit 52 receives the rebar cross-sectional shape from the storage unit 51 and the torch height Yp from the Y-axis position detector 38, and receives the position of the torch repetition point 45 in the X-axis direction and the welding end point in each pass. 4
The position of 4 is calculated. When the comparator 53 matches the reversal position XPO in the path with the X-axis position XP detected by the X-axis position detector 37, the comparator 53 issues a reversal command to the X-axis drive control circuit 54, and the X-axis slide mechanism 35 The driving direction is reversed, and the welding torch 3 is moved in the opposite direction. In this way, the welding torch 3 is reciprocated in the X-axis direction while being inverted at the torch repetition point 45 in the X-axis direction, and welding is sequentially performed for each layer. When the position of the welding end point 44 is reached, the welding sequence control circuit 55 automatically ends the welding according to the welding end reversal command sent from the calculator 52.

Therefore, the arc welding of the rebar can be automatically performed. In addition, even if there is a variation in the gap of the groove portion 2 or a variation in the degree of adhesion of the backing material 11, the groove portion 2 is not affected.
Can be changed in the amount of the deposited metal necessary to fill the gap. Further, since the welding is performed while rotating the arc at a high speed, as shown in FIG. 6, the cross-sectional shape of the weld bead 100 is concavely curved due to the dispersion of the arc force, and the bead shape becomes good. Also, because the penetration does not concentrate in the center,
A uniform penetration with a wide bead width is obtained, and the groove side wall 101 is formed.
The penetration P2 into the steel also increases compared to the conventional one (P2>
P1). For this reason, welding defects such as defective fusion do not occur in the laminated portion of the bead.

Next, as a specific example, using the above-described automatic welding apparatus, joint welding of a deformed reinforcing bar of D38 was performed under the welding conditions shown in Table 1. However, a 1.2 mm diameter solid wire is used for the welding wire, and Ar + 20% C is used for the shielding gas.
A mixed gas of O ₂ was used.

[0021]

[Table 1]

As a result, no weld defect such as undercut was observed in the cross section of the welded joint portion, and a satisfactory joint was obtained without burn-through of the outer peripheral portion. In addition, the welding time was reduced to about 4 minutes, which is half that of manual welding.

[0023]

As described above, according to the present invention, the joint welding of the reinforcing steel is performed while the arc is rotated at a high speed. Therefore, the bead shape at the joint of the reinforcing steel is improved, and the occurrence of welding defects is prevented. be able to. In addition, since the welding control device controls the position of the repetition point of the reciprocating movement of the welding torch in the X-axis direction and the automatic stop control of the welding,
It is possible to achieve automation and labor saving of joint welding of reinforcing bars. In addition, even if there is variation in the groove width, the perpendicularity of the groove cut surface, the degree of adhesion of the backing material, etc., the welding control device controls the amount of weld metal required to fill the groove. Therefore, a high quality rebar joint can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of an automatic arc welding apparatus showing one embodiment of the present invention.

FIG. 2 is a partial cross-sectional front view of the chamber jig of FIG.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a block diagram of a welding control device.

FIG. 5 is a view showing a reinforcing bar welding lamination pattern.

FIG. 6 is a view showing a sectional shape of a welding bead by a rotating arc.

FIG. 7 is a view showing a cross-sectional shape of a conventional welding bead formed by an arc without rotation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rebar 2 Groove 3 High-speed rotation welding torch 4 Electrode nozzle 5 Welding tip 6 Welding wire 10 Chamber jig 11 Backing material 20 Insertion opening 21 Nozzle mechanism 31 Clamp device 33 Y axis slide mechanism 35 X axis slide mechanism 37 X axis Position detector 38 Y-axis position detector 40 Fine adjustment screw 50 Welding control device 51 Reinforcing bar shape memory 52 Computing unit 53 Comparator 54 X-axis drive control circuit 55 Welding sequence control circuit

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI B23K 37/053 B23K 37/053 G 37/06 37/06 C E04C 5/02 E04C 5/02

Claims (1)

(57) [Claims] 1. A welding machine comprising: a chamber jig attached to a welding portion of a pair of rebars to be welded; a welding machine main body for performing arc welding of the rebar; and a welding control device for automatically controlling the welding machine main body. The chamber jig comprises: a jig member for clamping a pair of reinforcing bars at a predetermined interval; a mechanism for supporting a welding backing material on a part of an outer periphery of a welding groove of the reinforcing bar; A welding mechanism for jetting a shielding gas to a portion of the welding torch; a welding torch for rotating a welding wire at a tip of the torch at a high speed; a Y-axis slide mechanism for moving the welding torch in a torch axis direction; and the welding torch. X-axis slide mechanism for moving the welding torch in a direction perpendicular to the torch axis and parallel to the joint end surface of the reinforcing bar, an adjusting axis capable of adjusting the welding torch in a groove width direction, and an X-axis and a Y-axis of the welding torch. A position detector for detecting the position of each direction, the welding control device includes: a torch height control unit using an arc sensor; a storage unit that stores information on a cross-sectional shape of a reinforcing bar; and a position detector in the Y-axis direction. By giving the detected torch height, the position of the repetition point of the reciprocating movement in the X-axis direction of the welding torch is calculated according to the cross-sectional shape of the reinforcing bar stored in the storage means, and the X-axis slide mechanism is used. Control means for repetitively moving the welding torch; and providing the torch height detected by the position detector in the Y-axis direction to terminate welding according to the cross-sectional shape of the reinforcing bar stored in the storage means. Torch Y
An automatic arc welding apparatus for rebars, comprising: a control unit that calculates an axial height and automatically stops welding.