JPH0642989B2 - Welding equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a welding device capable of automatically performing circumferential welding of a steel pipe or the like.

Conventionally, when welding a flange to the end of a square steel pipe, the object to be welded was attached to the positioner and welding was performed manually, but with this method, the operator must always hold the torch and perform the work. It required a lot of labor because it had to be done. Various welding devices have been developed as devices for automatically performing such welding work.
There are drawbacks that the mechanism is complicated and expensive, the welding cable is twisted, continuous welding cannot be performed, and welding defects easily occur.

In order to improve these drawbacks, a floating table which is freely movable in the X-axis and Y-axis directions and is rotatable, and a magnet roller which is driven at a fixed position and contacts the peripheral surface of a workpiece (weld), And a welding torch that is supported between the shafts of the magnet rollers and has a welding part and a crater aligned with each other,
A welding device has been proposed in which a workpiece is placed on a floating table and welded while rotating (working application No. 57-17686), but the weight of the workpiece is large (for example, 250 kg. In the above case, a large force is required to move the work piece due to the frictional force generated in the movable part, and the inertia of the work piece becomes large, so that it may not be able to follow the drive magnet roller well. . In particular, when the shape of the welding line changes sharply, there is a problem that the driving magnet roller and the object to be welded are separated from each other or slip occurs, and normal welding cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above-mentioned problems of the conventional welding apparatus and to provide an automatic welding apparatus that is mechanically simple and can easily perform circumferential welding of pipes and the like without defects. This will be described below.

The welding apparatus according to the present invention is supported by a rotatable table for placing an object to be welded, which is provided at a fixed position, and an arm whose position can be changed relative to substantially the center of the table, and is rotatable with respect to the arm. A welding head, and at least one pair of rollers that are arranged along the welding line of the workpiece to be in contact with the outer surface of the workpiece during welding, and a pair of these rollers. It is characterized in that a driving device for rotationally driving at least one of them and a welding torch facing the welding line are provided. Hereinafter, an embodiment shown in the drawings will be described.

1 and 2 are side sectional views showing an example of a welding apparatus according to the present invention, and FIG. 3 is a plan view showing a part of the welding apparatus.
And a welding head 3 and a supporting device 4 for supporting the welding head 3. The rotary table 2 has a rotary shaft 5 at its center and is rotatably supported in a horizontal plane by a bearing 7 fixed on a substrate 6. The welding head 3 has a plurality of recesses on the front surface side, and is pivotally attached to an arm 9 of the supporting device 4 in a horizontal plane by a support shaft 8 provided at an intermediate portion in the vertical direction. A motor 11 is attached to the uppermost portion of the welding head 3, and a drive gear 15 is fixed to a rotary shaft 13 that is projected into the uppermost recess 12. On the front surface of the welding head 3, right and left two roller shafts 17 and 17 'are juxtaposed so as to sandwich the support shaft 8. The roller shafts 17 and 17 'are rotatably supported by upper and lower bearings 19 and 20, and a driven gear 21 that meshes with the drive gear 15 is attached to the upper end of one roller shaft 17. Further, drive rollers 27, 27 ′ located in the middle recess 23 and the lower recess 25 are provided in the middle of the roller shaft 17. The other roller shaft 17 'is independently rotatable regardless of the drive gear 15, and upper and lower floating rollers 29, 29' are provided in the middle thereof. The driving rollers 27, 27 'and the floating rollers 29, 29' are preferably made of a magnetic material that is magnetically attached to the object to be welded. Further, it is preferable that the outer peripheral portions of these rollers are subjected to knurling or the like to increase the frictional force. The drive rollers 27, 27 'and the floating rollers 29, 29' are
These rollers are installed vertically offset from each other.
The sum of the radii (r) of 27 (27 ') and 29 (29') is for both roller shafts 1
Since it is larger than the inter-axis distance of 7,17 ', both rollers 27 (27') and 29 (29 ') are partially overlapped by a length d in the axial direction view (plan view in the illustrated example). There is.

In the illustrated example, the drive rollers 27, 27 'and the idle rollers 29, 29' are all formed as rollers of equal diameter (2r), and the roller shaft 1
Although 7,17 'and the support shaft 8 are provided side by side on a straight line, the diameters of the driving roller and the idler roller may be different from each other in some cases, and the support shaft 8 and the roller shafts 17,17' are linearly arranged. It does not have to be placed above.

In addition to the drive rollers 27, 27 'and the floating rollers 29, 29', more rollers may be provided. Further, the driving roller 27 and the floating roller 29 may not be provided in the upper and lower two as in the illustrated example, but may be provided in each one.

A welding torch 30 is attached to a support frame 3a protruding from the lower end of the welding head 3. The welding torch 30 is provided below the space between the roller shafts 17 and 17 ', and is supported so as to face the welding line W so that the extension line of the shaft coincides with the welding line W. In the figure, 30a is a welding rod (wire) which is automatically fed out by a feeding device (not shown).

The support device 4 includes a column 33 that is erected on the substrate 6 and a column 33.
The base 9a of the arm 9 is slidably fitted to the support cylinder 35.
A guide roller 37 is provided at the outer front end of the support cylinder 35, and a wire 39 having one end fixed to the end of the base 9a of the arm 9 is provided.
Is hung on this. A weight 40 is suspended at the opposite end of the wire 39, and the weight of the weight 40 urges the arm 9 so as to always project forward, that is, toward the workpiece. Instead of these weights 40 and wires 39,
The arm 9 may be pushed forward by a spring.

When using the welding apparatus 1, first, the rotary table 2
The object to be welded is placed on the table so that its center substantially coincides with the center of the table 2, and is fixed by an appropriate fixing means such as a fixing metal fitting or a bolt. In the illustrated example, the objects to be welded are the rectangular steel pipe 45 and the flanged square steel plate 46 welded to the lower end thereof. Next, when the rollers 27, 27 ', 29, 29' of the welding head 3 are brought into contact with the outer peripheral surface of the square steel pipe 45 which is the object to be welded and the motor 11 is started, the drive rollers 27, 27 'rotate. Therefore, since the workpieces 45 and 46 against which they are pressed rotate together with the rotary table 2 due to the frictional force with the rollers, welding power may be supplied in this state to perform welding.

The welding head 3 that supports the welding torch 30 is supported by the extendable and contractible arm 9 and can freely rotate about the support shaft 8. Therefore, the corner of the square steel pipe 45 that is the object to be welded. Even if it is in the section, roller 27 (2
7 ') and 29 (29') contact the welding surface, so that the welding torch 30 is always kept in a constant direction relative to the welding spot.
Further, the object to be welded is driving rollers 27, 27 'on the welding head 3 side.
Since it is rotated by, it is possible to maintain a constant welding speed at all times.

With this welding device, the welding head only follows the object to be welded, and the welding head follows the object to be welded, and the welding head does not move even if the weight of the object to be welded is large. It does not separate from the work piece or move out of position. Further, the drive roller (27 (27 ') and the idle roller 29 (2'
9 ') is displaced in the axial direction so that they partially overlap each other in a plan view, so it is possible to make the distance between the shafts of the roller shafts 17, 17' smaller than the roller diameter. It is possible to suppress the difference in the distance between the welding torch 30 and the welding point between the case where the surface to be welded is a flat surface and the case where the surface is a curved surface having a small radius of curvature, without providing a copying device for use. Of.

FIG. 5 shows an embodiment different from the above, in which the arm 9'of the supporting device 4 is rotatably supported in the horizontal plane by the shaft 50 provided at the upper end of the column 33 ', and is welded by the spring 51. It is biased toward the object side. The tip of the arm 9'is bent in a hook shape toward the object to be welded.
A welding head 3 similar to that in the previous embodiment is supported by a support shaft 8 at the tip of b'to be rotatable in a horizontal plane. In the above-mentioned embodiment, the relative position with respect to the table center can be changed by expanding and contracting the arm 9, whereas in the present embodiment, the above-mentioned relative positional relationship is changed by rotating the arm 9 '. Are configured to vary. In any case, the welding head 3 is
Since it is rotatably provided with respect to 9 ', the arm 9,
The welding head 3 supported by 9'can well follow the irregularities on the outer surface of the object to be welded and keep the welding torch 40 in a predetermined direction.

In the above embodiment, an example was described in which the rotary table 2 was held horizontally and welding was performed, but it goes without saying that welding can be performed in a state in which it is vertical or inclined with respect to the horizontal plane. Further, although the case where electric welding is performed has been described in the above example, gas welding or melting of a workpiece can be automatically performed by using a similar device.

As described above, the welding apparatus according to the present invention is an excellent one that is mechanically simple and can easily perform circumferential welding of steel pipes without defects.

[Brief description of drawings]

1 and 2 are side views showing a part of a welding apparatus according to the present invention in a cross section, FIG. 3 is a plan view showing a part of the welding device, and FIG. A- in the figure
The section A and the section B-B in FIG. 2 are respectively shown. FIG. 4 is an enlarged perspective view of a main part, and FIG. 5 is a plan view showing a different embodiment. 1 ... Welding device, 2 ... Rotary table, 3 ... Welding head, 4 ... Supporting device, 6 ... Substrate, 8 ... Supporting shaft, 9,
9 '... arm, 11 ... motor, 17,17' ... roller shaft, 27,27 '... driving roller, 29,29' ... idling roller,
30 ... Welding torch.

Claims (3)

[Claims] 1. A welding head, which is provided at a fixed position and is supported by a rotatable table for placing an object to be welded, and an arm whose position is variable relative to substantially the center of the table, and which is rotatable with respect to the arm. The welding head includes at least one pair of rollers arranged in parallel along the welding line of the workpiece and contacting the outer surface of the workpiece during welding, and at least one of the pair of rollers. A welding device, characterized in that a driving device for rotating one of them and a welding torch facing the welding line are provided. 2. The welding device according to claim 1, wherein the roller is made of a magnetic material. 3. A pair of rollers are arranged such that the axial positions of both rollers are alternately shifted so that they partially overlap each other when viewed in the axial direction, and the axial distance between both rollers is greater than the sum of the radii of both rollers. The welding device according to claim 1 or 2, which is made smaller.