JP2008221302A - Arc welding equipment for steel pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide arc welding equipment for steel pipe, equipment that can actualize sure grounding as well as preventing electricity from conducting to a driving device and that can stably rotate steel pipe free of uneven rotation, for the purpose of efficiently mass-producing high quality steel pipe in which homogeneous weld bead is formed by arc welding. <P>SOLUTION: The arc welding equipment includes: two driving rollers 2a, 2b which are arranged horizontally in parallel on a base 1 having a ground wire; and a driving device M which is connected to the non-welding operation side end of these driving rollers 2a, 2b. The two driving rollers 2a, 2b each have flanges 51a, 51b, 52a, 52b projectingly provided near both right and left ends, wherein at least the flanges 51a, 51b on the welding operation side end are projectingly provided in plurality with spaces apart. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is an arc welding apparatus for hollow steel pipes, solid steel rods and the like (hereinafter collectively referred to as “steel pipes”), and in particular, welds other metal members to the tip portion of the steel pipe. In particular, the present invention relates to an arc welding apparatus suitably used.

  To connect multiple pipes in the longitudinal direction using a steel pipe with a circular cross-section as a base material, or to weld other metal members to the ends of these steel pipes, a uniform weld bead is required to wrap around the outer peripheral surface of the steel pipe. Since it is necessary to form, the apparatus and method which perform a welding operation, rotating a steel pipe conventionally are proposed.

  For example, in the pipe welding apparatus and the pipe welding method according to Patent Document 1, the steel pipe is placed on a carriage having wheels that are brought into rolling contact with the outer peripheral surface of the temporarily welded steel pipe, while the driving apparatus supported by the carriage is used. It has been proposed to perform a welding operation over the entire circumference in the cross-sectional direction of the steel pipe while rotating the steel pipe with a driving device while fixing the position of the torch by winding an endless strip between the steel pipes.

  However, the above-mentioned welding apparatus has a drawback that it is necessary to rewind the endless strip every time the steel pipe after the welding work is replaced with a new unprocessed steel pipe, and the welding work process becomes complicated. Therefore, the wheel on the pedestal side is used as a drive roll, and the steel pipe is placed on the drive roll, and the steel pipe is rotated around the axis, while the position-fixed torch is brought into contact with the entire circumference in the transverse direction of the steel pipe. A method of performing work has also been proposed (Patent Document 2). If such a method is used, there is an advantage that it is possible to shift to the next welding operation only by replacing the steel pipe.

JP-A-5-177389 JP-A-7-241683

  In any case, when performing arc welding work over the entire circumference of the steel pipe while relatively rotating the steel pipe and its mounting table, it is possible to realize a reliable grounding and drive in order to form a homogeneous weld bead. It is important to prevent energization of the apparatus and to stably rotate the steel pipe without uneven rotation.

  However, it is impractical to attach and detach the earthing device to and from the steel pipe that rotates on the mounting table because it reduces work efficiency, and it is not possible to make a grounding via the mounting table that should always be in contact with the steel pipe. It was also not easy to do. In particular, for example, when the steel pipe is a long-diameter, small-diameter pipe body, the steel pipe is often bent slightly for manufacturing or transportation / storage reasons, but the axis of the steel pipe is eccentric. As a result, uneven contact between the steel pipe and its mounting table was likely to occur, and unevenness was likely to occur in the ground. In addition, the grounding was likely to be uneven due to the presence of a protective film applied to the surface of the steel pipe and subsequent rust and dirt.

  In addition, the steel pipe with the eccentric shaft core is likely to cause unevenness in the rotation of the steel pipe itself, and depending on the degree of bending, there is a risk that one end of the steel pipe jumps up during the welding operation.

  Therefore, in order to efficiently mass-produce a high-quality steel pipe in which a homogeneous weld bead is formed by arc welding, the present invention can realize reliable grounding and prevent energization of the driving device, and An object of the present invention is to provide an arc welding apparatus for a steel pipe that can be stably rotated without causing uneven rotation of the steel pipe.

  In order to solve the desired problem, in the arc welding apparatus for steel pipes according to the present invention, two driving rollers arranged horizontally and in parallel on a base having a ground wire, and non-welding of these driving rollers A drive device connected to the work side end, and the two drive rollers are provided with flanges projecting in the vicinity of both left and right ends, and at least the flange at the welding work side end. A plurality of sheets were provided apart.

  While using the same long drive roller to support and rotate the long steel pipe, the steel pipe as the welding base material is not directly supported and rotated on the drive roller, but protruded from both ends of the drive roller By supporting with a flange, the contact point between the driving roller and the steel pipe was made a line contact. The drive device is connected to the non-welding work side end of the drive roller, or at least a plurality of flanges at the welding work side end are projected apart from each other. This is to reduce the influence of the current on the drive device as much as possible.

  By attaching the rotation axis of the drive roller on the base, power is supplied from the welded steel pipe to the grounding wire via the drive roller and the base, but more reliable grounding is achieved. In order to do this, it is preferable that the end of the metal chain is always in contact with the base while a heavy metal chain is wound around the drive roller. Heavy metal chains, such as those used for drive transmission of heavy machinery, are suitable as current-carrying members because they slide on the surface while being wound around a rotating drive roller, and can be easily replaced when worn. It is.

  Here, it is desirable to use a motor with a speed reducer to suppress the rotational speed of the steel pipe while securing the rotational torque. However, the drive device needs to be decelerated to block the influence of the welding current on the motor. The machine can be oil type.

  In addition, by using a flange with a bearing as a flange protruding from the non-welding work side end of at least one drive roller, two drives are used when a steel pipe with an eccentric shaft core is used as a welding base material. The rotation unevenness of the steel pipe rotating between the rollers (more precisely, between the flanges protruding from the drive roller) can be absorbed by the flange with the bearing.

  In the steel pipe arc welding apparatus according to the present invention, flanges are respectively provided near the left and right ends of the drive roller, which are near the left and right ends of the steel pipe as a weld base material, and the steel pipe is supported by line contact with the flanges. On the other hand, since a large number of flanges are in contact with the end portion on the welding work side so that the energization position is biased toward the welding work side, reliable grounding can be realized particularly on the welding work side. As a result of always being able to realize a good ground state, for example, it is possible to weld a carbon steel material such as 45C to the tip of an iron steel pipe without any problem.

  Moreover, the influence of the welding current with respect to a motor can be interrupted | blocked completely by making the reduction gear in a drive device into an oil type, and durability as a welding apparatus can be improved.

  As described above, in the steel pipe arc welding apparatus according to the present invention, a steel pipe that is a weld base material is supported by line contact with a flange protruding from the drive roller, thereby rotating between two drive roller valleys. In some cases, the flange protruding from the non-welding work side end of at least one drive roller is a flange with a bearing, so that the shaft core is eccentric to be bent. Even steel pipes can be rotated stably.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view showing an example of an arc welding apparatus for steel pipes according to the present invention. As shown in the figure, the apparatus according to the present invention has two drive rollers 2a and 2b arranged horizontally and in parallel on a base 1 having a ground wire (not shown) to the ground. Has a configuration. The driving rollers 2a and 2b and the base 1 are omitted in the middle for the convenience of drawing, but are configured to have a length corresponding to the length of the steel pipe as a weld base material.

  Each drive roller 2a, 2b is mounted on the base 1 by means of pillow type bearings 6a, 6b at the small-diameter drive shafts 21a, 21b extending outward from both ends. The flanges are provided in the vicinity of the left and right ends. In the apparatus of this example, a total of five flanges 51a and 51b are provided at equal intervals on the welding work side (left side in FIG. 1), but the energization amount during welding is concentrated on the welding work side. If possible, the number of the flanges 51a and 51b provided is arbitrary, and the interval between the flanges can be arbitrarily set. And the arrangement | positioning space | interval of the two drive rollers 2a and 2b will be set in consideration of the outer diameter of these flanges 51a and 51b.

  The drive rollers 2a and 2b use hollow and large-diameter steel pipes, and when the drive shafts 21a and 21b are inserted into the steel pipes from both ends, the drive rollers 2a and 2b have outer diameters that match the steel pipe inner diameters. Further, by centering and stabilizing the drive shafts 21a and 21b, a plurality of doughnut-shaped rings or flanges are separated and externally fitted.

  On the other hand, on the non-welding work side (the right side in FIG. 1) of the drive rollers 2a and 2b, one flange 52a and 52b are provided to project. Then, at least one flange with a ball bearing is used.

  On the non-welding operation side of the device, the drive shaft 21b and the drive device M on the front side are connected between the two drive shafts 21a and 21b via the sprocket 7 and the roller chain 8 provided on the drive shafts 21a and 21b. Are connected. The drive device M of this example includes an electric motor 4 and a speed reducer 3. A pulley 41 provided on the output shaft of the motor 4 and a pulley 31 provided on the input shaft of the speed reducer 3. Are connected by a V-belt 9 and a sprocket 7 provided on the output shaft of the speed reducer 3 is connected to a drive shaft 21b provided on the drive shaft 21b of the drive roller 2b located on the near side by a roller chain 8. Has been. In this example, a motor 4 having a specification of 1700 to 1720 rpm and an output of 0.2 KW is used as the motor 4, and an oil type having a reduction ratio of 1:30 is used as the speed reducer 3.

  Also, on the welding work side of the apparatus, the two drive shafts 21a and 21b are connected via the sprocket 7 and the roller chain 8 provided on the drive shafts 21a and 21b. Accordingly, the driving force starting from the output shaft of the motor 4 is transmitted from the pulley 41 to the pulley 31 provided on the input shaft of the speed reducer 3 via the V-belt 9 and then from the sprocket 7 of the output shaft to the roller chain. 8 is transmitted to the driving roller 2b on the near side and from the driving roller 2b on the near side to the driving roller 2a on the far side.

  By the way, in the apparatus of this example, a total of five metal chains 10 are wound around the drive rollers 2a and 2b. These metal chains 10 are not fixed to the driving rollers 2a and 2b simply by hanging heavy ones. As each drive roller 2a, 2b rotates, it slides on its surface, so that the end is always in contact with the base, so that effective earthing is achieved.

  FIG. 2 is a schematic longitudinal sectional view showing a state in which a steel pipe as a welding base material is placed on a drive roller in the apparatus. As described above, when the driving roller 2b on the near side and the driving roller 2a on the back side are interlocked and rotated counterclockwise by the driving force of the motor 4, the flanges 51a and 51b protruding from the driving rollers 2a and 2b are provided. The steel pipe W, which is a welding base material placed on the top, also rotates counterclockwise. At this time, since the metal chain 10 slides on the driving roller 2b with both ends being in contact with the base 1, when the welding operation is performed on the steel pipe W, the driving roller 2b and the metal chain 10 are moved from the flange 51b. Then, power is supplied to the ground wire through the base 1.

It is the schematic plan view which showed an example of the arc welding apparatus for steel pipes which concerns on this invention. In the apparatus of FIG. 1, it is a schematic longitudinal cross-sectional view which shows the state which mounted the steel pipe used as a welding base material on the drive roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2a, 2b Drive roller 3 Reduction gear 4 Motor 6a, 6b Bearing 7 Sprocket 8 Roller chain 9 V belt 10 Metal chain 21a, 21b Drive shaft 31, 41 Pulley 51a, 51b Flange (welding work side)
52a, 52b Flange (Non-welding work side)
M Drive unit W Steel pipe

Claims (3)

It comprises two drive rollers arranged horizontally and in parallel on a base equipped with a ground wire, and a drive device connected to the non-welding work side ends of these drive rollers, A steel pipe arc welding apparatus characterized in that flanges are provided in the vicinity of both left and right ends, and a plurality of flanges at least at the welding work side end are provided apart from each other. The arc welding device for a steel pipe according to claim 1, wherein the drive device is provided with an oil-type speed reducer. The steel pipe arc welding apparatus according to claim 1 or 2, wherein a flange protruding from a non-welding work side end of at least one drive roller is a flange with a bearing.

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