JP2005177801A - Short pipe seam welding equipment, and short pipe seam welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent the deformation of a short pipe before being seam-welded, and the deformation caused by thermal expansion and heat strain during and after the seam welding. <P>SOLUTION: In the short pipe seam welding equipment, a short pipe holding mechanism 10 is arranged adjacently to a final forming means 20C, and an discharging means 40 is arranged adjacently to the discharge edge of the short pipe holding mechanism 10. In the short pipe holding mechanism 10, a small-diameter roll 11 is arranged parallel to the axis of a cylindrical casing 12, and the diameter of the circumscribed circle in the small-diameter roll 11 is made smaller than the outside diameter of an intermediate pipe material 1. The final forming means 20C is composed of vertical and horizontal four concave rolls 16C. The diameter of the circular rings in the circular forming faces by the circular-arcuate roll faces in the concave rolls 16C is made smaller than the outside diameter of the intermediate pipe material 1. The discharging means 40 is composed of vertical and horizontal four concave rolls 13. The diameter of the circular rings in the circular faces by the circular-arcuate roll faces in the concave rolls 13 is made smaller than the outside diameter of the short pipe 1, and the feed rate is made the same as that in the final forming means 20C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

In this invention, short open pipes (open pipes having a C-shaped cross section) are sequentially reduced in diameter, shaped into a circular cross section, and a work (intermediate pipe material) shaped into a circular cross section is fed into a welded portion, and the seam (butting portion) ) To manufacture short pipes, and products related to short pipe shape and dimensional accuracy, such as motor casings, muffler (silencer) outer cylinders, etc. It can be effectively used for the production of short pipes.
The basic idea of the present invention can also be used for seam welding of long pipes (butt welding of end edges in the longitudinal direction; the same applies hereinafter), thereby producing long pipes with high shape accuracy and high dimensional accuracy. You can also

Generally speaking, a conventional short pipe seam welding apparatus is roughly composed of a workpiece supply mechanism, a forming mechanism, and a seam welded portion, and some have a discharge mechanism.
The workpiece supply mechanism is a mechanism that feeds the workpiece seam line into the forming mechanism while pressing it while guiding it with the seam guide. Before entering the forming mechanism, the seam part matches the welding tool such as a torch. The posture of the work (open pipe) (the position of the seam portion) is adjusted and fed to the forming mechanism while being guided by the seam guide.
The forming mechanism needs to reduce the diameter of the workpiece, finally shape it into an intermediate pipe member having a circular cross section, and feed the workpiece into the welded portion while keeping the seam line of the workpiece in a predetermined position. The seam guide is generally a blade, and the workpiece final shaping means is generally a pair of left and right drum rolls.
Further, the workpiece is shaped into an intermediate pipe material by the final shaping means of the forming mechanism, sent to the welding mechanism, and seam welded with a welding tool when protruding from the final shaping means. There are various types of welding tools such as gas welding and electric welding.

In general, workpiece feeding and forming (shaping) are performed by a drum roll, and an example thereof is described in Japanese Patent Application Laid-Open No. 55-247872. This is one in which the workpiece is sequentially sent while being reduced in diameter by two-stage drum-shaped rolls before and after (details will be described later).
On the other hand, forming is performed with a reduced-diameter die, the workpiece is pushed into the reduced-diameter die by a feed mechanism, the diameter is reduced by the taper surface of the reduced-diameter die, and the cross-sectional shape is shaped, and the diameter is reduced while being held by the cylindrical surface of the reduced-diameter die. There is also a type in which seam welding is performed with a torch when protruding from a die and protruding from a reduced diameter die (for example, Japanese Patent Publication No. 2-15310). In this case, the forming means is a diameter-reducing die, and the sliding resistance due to the diameter-reducing die is extremely large. Therefore, when the work is fed into the diameter-reducing die with a drum-shaped roll, the drum-shaped roll slips and the moving speed of the work is increased. In order to fluctuate, this prior art uses a hydraulic cylinder as the feeding means to force the workpiece into the reduced diameter die.

  In short seam welding equipment, in order to avoid poor welding at both front and rear ends of the workpiece, the workpiece can be pushed and sent to the forming mechanism so that the workpiece passes sequentially through the weld without being interrupted. In addition, in the case of the above-described conventional technique using a reduced diameter die, the frictional resistance between the reduced diameter die and the work is large, so it is necessary to push the work into the reduced diameter die at a constant speed with a strong feed force. However, as a practical matter, it is extremely difficult to push the workpiece into the reduced diameter die by pushing the workpiece with a hydraulic cylinder that operates intermittently. In the case of using a reduced diameter die, there is a possibility that the surface of the work may be scratched due to friction with the inner surface of the reduced diameter die, and the thin short tube and the small diameter short tube are deformed when subjected to a strong pushing force. Because it is easy, it is not suitable for the production of relatively long short tubes. Furthermore, in the above-described prior art, seam welding is performed when the workpiece protrudes from the reduced diameter die, and the welded portion is thereafter free (unconstrained), so that deformation due to expansion and thermal distortion due to welding heat is large. Therefore, this prior art is not suitable for high quality short pipe seam welding.

Since the invention of this application is based on the prior art (Japanese Patent Laid-Open No. Sho 55-247872) that performs forming (shaping) and feeding with a drum-shaped forming roll, the main part of this prior art is shown in FIG. Further details will be described with reference to FIG.
In this, four sets of rolls 111 to 114 by a pair of left and right drum-shaped rolls are arranged in a line, and these are driven at the same speed to sequentially feed the work at the same speed.

  The workpiece w is adjusted to a state in which the seam s is directly above and is sequentially introduced into the feed mechanism (by the conveyor 117), and is guided with the seam s directly above by the blade-like seam guide 118 of the feed mechanism. Then, it is fed into the drum-shaped roll 111 at the right end in the pressed state. Then, it is sandwiched between the right-hand drum roll 111, slightly reduced in diameter, and sent to the drum-shaped roll 112. The workpiece w is fed into the drum-shaped roll 112, further reduced in diameter, shaped into an intermediate pipe material, and fed into the drum-shaped roll 113. Since there is a torch T at the position of the drum roll 113, seam welding is started almost simultaneously with the left edge of the work being gripped by the drum roll 113, and then the drum rolls 112 and 113 are sent at the same speed, Eventually, the rear end is detached from the drum-shaped roll 112. After the rear end is disengaged from the drum-shaped roll 112, seam welding is performed in a state of being gripped only by the drum-shaped roll 113, and sent to the drum-shaped roll 114.

In addition, the workpiece | work w is arranged in the state of pressing in the workpiece | work supply mechanism by the conveyor 117, and passes the drum-shaped rolls 111-114 in the same state after that.
This is a work in which a C-shaped work (open pipe) is pressed by left and right drum-shaped rolls to be shaped into an intermediate pipe material having a circular cross section, and the seam edge is abutted and pressed strongly. In this case, since the workpiece is not restrained in the vertical direction, it swells in the vertical direction and slightly deforms into an elliptical shape. Therefore, the intermediate pipe material is welded by the torch T in a state where the seam portion is slightly expanded outward. At this time, the seam part melts for welding and the vicinity thereof is heated to a high temperature, so that the seam part swells and deforms further outward in the radial direction during welding.

In addition, when the rear end of the work is detached from the drum roll 112, it is gripped by the drum roll 113, but the rear end is free (unconstrained state). Therefore, deformation due to thermal expansion and deformation due to thermal strain are prevented. It cannot be prevented.
Further, the welded portion is free until it is gripped by the hourglass-shaped roll 114, and is also free from the time when the rear end comes off the hourglass-shaped roll 113 to reach the hourglass-shaped roll 114. Therefore, thermal deformation in this free state is inevitable.
The deformation described above varies depending on the length, thickness, thickness, material, and the like of the short pipe, and thus is not necessarily constant, and variation in shape accuracy is large.

  The problem of deformation during shaping by the drum roll 112, deformation due to welding heat, and deformation due to thermal distortion after welding strongly holds the intermediate pipe material in a circular cross-section during welding and remains in the same state for a while after welding. It is expected that the shape accuracy and dimensional accuracy of the short pipe (with the seam part welded) will be improved, so that the cylindrical short pipe is held adjacent to the final shaping means. It is conceivable to arrange the mechanism, hold the intermediate pipe material strongly with the short tube holding mechanism, perform seam welding in that state, and similarly hold with the short tube holding mechanism for a while after welding.

  However, when the intermediate pipe material is strongly held by the short pipe holding mechanism before and after welding as described above (the intermediate pipe material is strongly held by the short pipe holding mechanism and passed through the short pipe holding mechanism in that state). In addition, the holding length during this time becomes considerably long, and since the work is thermally expanded by welding heat and the holding force by the short tube holding mechanism is further increased, the frictional resistance to the work during that time becomes extremely large, This excessive frictional resistance may impair the shape accuracy of the workpiece (short pipe) immediately after welding. Therefore, if the intermediate pipe material and the short pipe (seam welded) are strongly held by the short pipe holding mechanism and are sent by pressing, the intermediate pipe material is subjected to a strong compressive force in the longitudinal direction by the feed force. When a strong compressive force in the longitudinal direction is applied, the intermediate pipe material swells slightly in the radial direction, which also increases the frictional resistance, and the resistance to feeding is further increased.

On the other hand, the feeding force of the final shaping means by the pair of left and right drum-shaped rolls facing each other is not large. Because the intermediate pipe material sandwiched between a pair of opposing drum-shaped rolls is deformed into an elliptical shape, the reaction force against the tightening force of the drum-shaped roll is small, and between the roll surface of the drum-shaped roll and the intermediate pipe material This is because the pressure contact force does not increase.
Therefore, special measures are taken so that the feeding force of the final shaping drum roll is strengthened while suppressing deformation of the intermediate pipe material, and the workpiece (intermediate pipe material and short pipe) is pushed smoothly into the short pipe holding mechanism. It is necessary to take.
Further, since the intermediate pipe material must be moved straight without a seam guide in the short pipe holding mechanism, the short pipe holding mechanism needs to have a special guide function for moving the intermediate pipe material straight.

From the above, devising the short pipe holding mechanism to reduce the frictional resistance against the work (intermediate pipe material and short pipe) by the short pipe holding mechanism as much as possible and to guide in the straight direction, short pipe holding Improve the shaping accuracy by the final shaping means so that the workpiece smoothly enters the mechanism, devise the mechanism of the final shaping means so as to generate the required feeding force, and further reduce the feeding burden of the final shaping means Thus, it is necessary to devise the discharge mechanism.
In addition, because the short pipe is relatively short, etc., it is not necessary to devise a special discharge mechanism when the short pipe can be moved forward in the short pipe holding mechanism without difficulty by only the feed force of the final shaping means. Not.
Japanese Patent Laid-Open No. 55-24787 Japanese Patent Publication No. 2-15310

The invention of this application is based on the premise that the work (open pipe having a C-shaped cross section) is finally shaped into an intermediate pipe material by a drum-shaped roll, fed into the short pipe holding mechanism, and seam welded at the approximate center of the short pipe holding mechanism. The following three points are to be solved.
(1) To devise the short pipe holding mechanism so as to reduce the frictional resistance against the work (intermediate pipe material and short pipe) by the holding surface of the short pipe holding mechanism as much as possible and guide it in the straight direction.
(2) To improve the shaping accuracy of the final shaping means so that the workpiece smoothly enters the short tube holding mechanism and to devise the mechanism of the final shaping means so that the required feed force is generated.
(3) Devise the discharge mechanism to reduce the burden of feeding the final shaping means.

The means for solving the above problems is that a short tube holding mechanism is arranged adjacent to the final shaping means using the drum-shaped roll, and a discharging means using the drum-shaped roll is arranged adjacent to the discharge end of the short tube holding mechanism. On the premise of the pipe seam welding apparatus, the short pipe holding mechanism, the final shaping means, and the discharging means are configured as follows.
Short tube holding mechanism (a) A large number of small-diameter rolls are arranged in an annular shape on the inner surface of the cylindrical casing, and these short-diameter rolls are arranged parallel to the axis of the cylindrical casing to constitute a short tube holding mechanism.
(B) The circumscribed circle diameter of the small diameter roll is slightly smaller than the outer diameter of the intermediate pipe material;
(C) A window hole for seam welding is provided in the cylindrical casing.
About final shaping means (d) The final shaping means is composed of four drum-shaped rolls on the top, bottom, left and right,
(E) The diameter of the ring of the annular shaping surface by the arc-shaped roll surface of the four upper, lower, left and right drum-shaped rolls is slightly smaller than the outer diameter of the intermediate pipe material,
About the discharging means (f) The discharging means is constituted by four drum-shaped rolls on the top, bottom, left and right,
(G) The diameter of the ring of the annular surface formed by the arc-shaped roll surfaces of the four upper, lower, left and right drum-shaped rolls is slightly smaller than the outer diameter of the short pipe,
(H) The feeding speed of the discharging means is the same as the feeding speed of the final shaping means.

[Action]
The workpiece is drawn into the final shaping means by four drum rolls with the seam position adjusted, and shaped into an intermediate pipe material. A substantially annular shaped surface is formed by the combination of the arcuate roll surfaces of the four upper, lower, left and right drum-shaped rolls. Accordingly, the work is pressed strongly in the radially inward direction substantially uniformly on the entire circumference, and is shaped into an intermediate pipe member having a circular cross section. On the other hand, since the intermediate pipe material is pressed radially inward from the top, bottom, left, and right, its rigidity is high against the external pressure acting on the entire outer periphery. On the other hand, the diameter of the ring formed by the annular shaping surface by combining the arcuate roll surfaces of the upper, lower, left and right four drum-shaped rolls is slightly smaller than the outer diameter of the intermediate pipe material. Strongly gripped by two drum rolls. Therefore, the intermediate pipe member is pushed with a strong feeding force by the final shaping means, and the movement in the rotational direction is restricted by the frictional resistance with the arc-shaped roll surface, so that the seam position does not change. Therefore, the workpiece is smoothly pushed into the short tube holding mechanism with the strong feeding force of the final shaping means while keeping the seam position constant.

  The seam position of the workpiece when pushed into the short tube holding mechanism is the same as the position adjusted by the loading mechanism, and the work is uniformly distributed on the entire outer periphery by a large number of small diameter rolls on the inner surface of the short tube holding mechanism. It is pressed and firmly held in the short tube holding mechanism while maintaining a circular cross section. At this time, the work outer peripheral surface is slightly elastically deformed radially inward at the portion where a large number of small diameter rolls are in pressure contact. Regulated by roll. Since the small-diameter rolls are arranged in parallel with the central axis of the short tube holding mechanism, this roll row provides a straight guide function for the workpiece and causes the workpiece to go straight. Therefore, when the workpiece tip reaches the welding position, the seam position coincides with the welding tool.

  The workpiece is welded in a state where the outer peripheral surface is uniformly pressed by a large number of small-diameter rolls and is strongly held in a circular cross section, and is also strongly held in a circular cross section after welding, so thermal expansion during and after welding It will not be deformed by thermal strain or the like. In this way, it is strongly held in a circular shape until it is pushed out from the short tube holding mechanism, and rapidly cools while passing through the short tube holding mechanism while maintaining a circular shape, so the short tube is molded with high shape accuracy and dimensional accuracy. The

In the short pipe holding mechanism, the intermediate pipe material is evenly pressed and strongly held by a large number of small diameter rolls, but this is held by a large number of small diameter rolls. small.
Moreover, since the intermediate pipe material and the short pipe held by a large number of small diameter rolls are slightly elastically deformed radially inward, the shape retention force (shape retention force) by the large number of small diameter rolls is Strong, but the tightening force on the intermediate pipe material is not so strong. In addition, the tightening force increases due to the thermal expansion of the intermediate pipe material due to the welding heat, but this is minor because it is relaxed by the elastic deformation of the intermediate pipe material, and the feed resistance of the workpiece due to the thermal expansion of the intermediate pipe material Does not increase significantly.

In addition, the work in the short tube holding mechanism is pushed by the succeeding work after the rear end of the work is removed from the final shaping means (four drum rolls). However, immediately after the tip protrudes from the short tube holding mechanism, it is gripped by the discharge roll and pulled out, so there is almost no resistance to the feeding of the final shaping means.
Therefore, the work advances smoothly in the short tube holding mechanism, and no strong compressive force in the longitudinal direction acts on the work. In addition, the work is completely moved by the large number of small diameter rolls of the short tube holding mechanism. Since the outer periphery is pressed evenly (excluding the portion of the weld line after welding), the workpiece is not greatly deformed by a strong compressive force in the longitudinal direction, and the shape accuracy and dimensional accuracy are not impaired.

Further, the discharging means is constituted by four upper, lower, left and right drum-shaped rolls, and an annular surface is formed by the roll surfaces of these drum-shaped rolls (discharge rolls), and the diameter of the annular ring of the annular surface is set as a short pipe. Since it is slightly smaller than the outer diameter, the short pipe is gripped evenly around its entire circumference, and like the final shaping means, the short pipe is strongly gripped by the discharge means without deformation, and at a constant speed. Pulled out.
In addition, since the feed speed of the discharging means is the same as the feed speed of the final shaping means, the workpiece fed into the short tube holding mechanism in the pressed state is the same as the inside of the short tube holding mechanism in the state where the front and back workpieces are sequentially abutted. Go straight on. Therefore, since the workpiece reaches the position of the welding jig in a state where the front and rear are sequentially abutted against each other, no welding failure occurs at the front and rear ends.

As described above, the work (intermediate pipe material) shaped to have a circular cross section by the final shaping means is firmly held by pressing the entire outer periphery evenly in the cylindrical short tube holding mechanism, and seam welding is performed in this state. Even after welding, the entire outer periphery is pressed evenly and held firmly in the short tube holding mechanism. Therefore, deformation before welding, thermal expansion during and after welding, and deformation due to thermal distortion are reliably prevented.
In addition, since the final shaping means is composed of four drum rolls on the top, bottom, left and right, the holding of the work is strong and the slip can be surely prevented. Since it can be pushed into the holding mechanism, on the other hand, the discharge means is a set of four drum rolls of upper, lower, left and right, similarly, the holding with respect to the work is strong, and slip can be reliably prevented, Therefore, the work can be reliably pulled out from the short tube holding mechanism at a constant speed.

Also, final shaping is performed with four drum rolls on the top, bottom, left and right, and the shaped intermediate pipe material is strongly held by a large number of small-diameter rolls in the short tube holding mechanism, and the discharging operation is performed by drum rolls on the top, bottom, left and right. Therefore, the workpiece can be fed smoothly at high speed, and short pipe seam welding can be performed efficiently.
Therefore, a high-quality short tube with high shape accuracy and dimensional accuracy and no surface damage can be manufactured very efficiently.

Next, an example in which the present invention is applied to seam welding of an iron short pipe will be described with reference to the drawings.
The invention of this application can be applied to a seam welding apparatus of a short pipe having a length of 200 mm to 1000 mm made of various materials such as an iron pipe, an aluminum pipe, and a copper pipe using various welding tools by gas and electricity.

(Overall mechanism of short pipe seam welding apparatus of embodiment)
In this embodiment, the work 1 (open pipe) moves from the right side to the left side in FIGS. 1 and 2, and the welded portion by the introduction mechanism 30, the forming mechanism 20, the short tube holding mechanism 10 and the torch 9 in order from the right side. The discharge mechanism 40 is provided (the same applies to FIGS. 3 and 4).
The open pipe (work 1) is obtained by bending a plate material into a C-shaped cross section, and is gradually reduced in diameter by the forming mechanism 20 and shaped into an intermediate pipe material having a circular cross section in which the seam portion 2 is in close contact. While being pushed into the short tube holding mechanism 10 as it is and passing through the short tube holding mechanism 10, it is seam welded by the torch 9 at substantially the center of the short tube holding mechanism 10, and from the short tube holding mechanism 10 to the discharge mechanism 40. Taken over and discharged.

Details of each mechanism of the embodiment are as follows.
1. About the Introducing Mechanism 30 As shown in FIG. 5, the introducing mechanism 30 has an introducing path 3 formed by a feed conveyor belt 15 on the lower surface and the left and right side plates 4, and in the traveling direction above the center of the introducing path 3 in the left-right direction. A long extending guide blade 5 is provided.
The distance between the left and right side plates 4 is adjusted to be several mm larger than the major axis according to the major axis of the open pipe (work 1). When the long diameter of the open pipe is approximately 116.5 mm, the distance between the side plates 4 is adjusted to 122.6 mm.
The feed conveyor belt 15 carries an open pipe (work 1) and conveys it to the first forming unit 20A.

2. About the forming mechanism 20 The forming mechanism 20 includes a first forming unit 20A, a second forming unit 20B, and a third forming unit 20C. An open pipe (work 1) is formed by the first forming unit 20A and the second forming unit 20B. The diameter is gradually reduced and finally shaped into an intermediate pipe material by the third forming portion 20C.

2-1. First forming unit 20A
The first forming section 20A is configured by arranging two sets of rolls, which are a combination of left and right drum rolls (first forming rolls) 16A, an upper two-wheel roll 16A ′, and a lower cylindrical roll 16A ″ in the front and rear. These rolls are made of urethane rubber in order to protect the work surface, reduce the manufacturing cost of the roll, protect the work surface, and the like.
The front roll set is as shown in FIG. 6, and the rear roll set is as shown in FIG.
A guide blade 5 extending from the introduction path 3 is provided between the left and right wheels of the upper two-wheel roll 16A ′.
The distance between the left and right drum-shaped rolls 16A and 16A and the distance between the upper and lower rolls 16A ′ and 16A ″ are adjusted according to the outer diameter of the short pipe to be manufactured.
When the long diameter of the open pipe (work 1) thrown into the introduction path 3 is 116.5 mm, the distance between the left and right drum-shaped rolls 16A, 16A of both the front and rear roll sets is 115.3 mm (FIG. 6). , FIG. 7).

2-2. Second forming unit 20B
The second forming unit 20B has the same configuration as the first forming unit 20A. However, it differs from the first forming portion 20A in that the seam guide between the left and right wheels of the upper two-wheel roll 16A ′ is a pair of front and rear guide rollers (rotating blades) 17.
A set of four front rolls is as shown in FIG. 8, and a rear roll set is as shown in FIG.
The distance between the left and right drum-shaped rolls (second forming rolls) 16B of both the front and rear roll sets is 114.2 mm (FIGS. 8 and 9).
The reason why the seam guide is provided in the second forming portion 20B is to seam guide the open pipe (work) until just before the third forming roll 20C (final shaping means), and the seam guide is used as the guide roller 17. This is because the frictional resistance is increased by being sandwiched between the seam guides by the seam edge, so that this frictional resistance is reduced. The guide roller 17 is a rotating blade and is a thin rotating disk having a sharp outer periphery.

2-3. Third forming unit 20C
The third forming unit 20C is a roll set in which four upper and lower, left and right drum-shaped rolls (third forming roll (final shaping roll)) 16C are combined. As shown in FIG. A 16C roll curved surface (a circular curved surface of the roll) forms an annulus. These drum-shaped rolls 16C are made of steel.
The distance between the upper and lower drum-shaped rolls 16C and 16C and the distance between the left and right drum-shaped rolls 16C and 16C are appropriately adjusted according to the diameter of the intermediate pipe material to be shaped (the same as the diameter of the short pipe). When the interval between the drum-shaped rolls (second forming rolls) 16B, 16B of the second forming unit 20B is 114.2 mm as described above, the circular diameter due to the roll curved surface of the drum-shaped roll 16C of the third forming unit 20C Is 112.9 mm.

The upper, lower, left and right drum-shaped rolls 16C are the same, rotate at the same speed, and drive the intermediate pipe material with the four drum-shaped rolls 16C to push into the short tube holding mechanism.
Although the third forming portion 20C is composed of left and right drum rolls and upper and lower drum rolls, the workpiece is prevented from being deformed into a vertically long ellipse by pressing it from above and below, and an intermediate pipe member having a circular cross section is formed. This is for final shaping. Therefore, when the required driving force for the intermediate pipe material can be sufficiently secured by the left and right drum-shaped rolls 16C, the upper and lower drum-shaped rolls may be made idle rolls and smaller than the left and right drum-shaped rolls. Is possible. However, the left and right drum-shaped rolls 16C need to be the same so as not to impair the shape accuracy of the intermediate pipe material.

3. Short Tube Holding Mechanism 10 As shown in FIG. 11, the short tube holding mechanism 10 includes a large number of cylindrical small-diameter rolls 11 on the inner surface. One set of annular rolls is formed, and a large number of these annular rolls are arranged in the cylindrical casing 12 at a predetermined interval in the front-rear direction, and each small-diameter roll 11 is an axis of the cylindrical casing 12. Are arranged in parallel.
These cylindrical small diameter rolls 11 are made of steel.

The small-diameter roll 11 has a diameter of 14 mm and a width of 5 mm, and the circumscribed circle diameter of the annular roll set is 113.1 mm, which is constant from the entrance side to the exit side.
The circumscribed circle diameter of the short pipe holding mechanism 10 is 0.53.1 mm smaller than the target outer diameter of the short pipe of 113.6 mm and is 113.1 mm, and the drum-shaped roll (third forming roll) 16C of the third forming portion 20C. The diameter is larger by 0.2 mm than the above-mentioned circular diameter (112.9 mm) due to the roll curved surface. By doing so, the intermediate pipe material shaped into a circular cross section by the third forming portion 20C is smoothly fed into the short tube holding mechanism 10, and the intermediate pipe material is radially inward by a large number of cylindrical small-diameter rolls 11. Since it is crushed slightly and gripped in a state of being elastically deformed into a waveform, it is prevented from rotating and goes straight in its posture.
In the center of the cylindrical casing 12 (300 mm in length) of the short tube holding mechanism 10, there is a copper base 81 having an opening 8 having a longitudinal length of 69.5 mm and a circumferential width of 12 mm. The tip of the torch 9 is inserted into the cylindrical casing 12 through the opening 8 of 81 (see FIG. 4).

An annular roll set in which ten small-diameter rolls 11 are arranged in the circumferential direction is a complete annular ring set of five small-diameter rolls 11 in the axial direction from the entrance of the short tube holding mechanism 10 to the base 81. (GG sectional view of FIG. 11) On the other hand, the annular roll set by the six small diameter rolls 11 in the axial direction behind the base 81 is an incomplete annular shape (C type) lacking the uppermost small diameter roll 11 and the like. (HH cross-sectional view of FIG. 11).
The reason why the annular roll set behind the base 81 is incomplete is to prevent the short-diameter weld 11 from touching the uppermost small-diameter roll 11 (FIG. 4).
Further, the short pipe holding mechanism 10 has no seam guide for holding the seam portion 2 of the open pipe (work 1) directly above, and the finally shaped intermediate pipe material (work 1) is pushed out from the third forming portion 20C. It is held by the short tube holding mechanism 10 in the posture as it is, and goes straight through the short tube holding mechanism 10 as it is.

4). About the discharge mechanism 40 The discharge mechanism 40 is constituted by one roll set in which four upper and lower, left and right drum-shaped rolls (discharge roll 13) are combined. As shown in FIG. An annular ring is formed by the roll curved surface of the discharge roll 13). These drum-shaped rolls 13 are made of steel. If the gripping force for the short pipe (work 1) is secured and the work 1 can be discharged at a constant speed, the drum roll 13 may be made of urethane rubber.
The upper and lower roll intervals and the left and right roll intervals are appropriately adjusted according to the diameter of the seam-welded short pipe. When the roll circumscribed circle diameter of the annular roll set of the small-diameter roll 11 of the short tube holding mechanism 10 is 113.1 mm (FIG. 11), the above-mentioned annular ring is formed by the roll curved surface of the drum-shaped roll (discharge roll 13) of the discharge mechanism 40. The diameter is 112.9 mm (FIG. 12). Due to the difference of 0.2 mm, the gripping force on the short pipe by the drum type roll (discharge roll 13) of the discharge mechanism 40 is strengthened, and the short pipe is smoothly pulled out from the short tube holding mechanism 10 and discharged.
An annular groove 131 is provided at the center of the drum-shaped roll (discharge roll 13) above the discharge mechanism 40, so that the weld line of the short pipe is released.

5). Main related dimensions 84 mm from the front end of the short tube holding mechanism 10 to the front end of the base 81, 136.5 mm from the front end of the short tube holding mechanism 10 to the torch 9, the axial center of the drum roll 16C of the third forming portion 20C To torch 9 is 188.5 mm.

6). Seam welding work according to the embodiment (1) An operator places an open pipe (work 1) having a length of 200 mm on the feed conveyor belt 15 of the introduction path 3 one by one. At this time, the operator inserts the guide blade 5 into the seam of the open pipe. The supplied open pipe is guided by the guide blade 5 with the seam right above, and is fed to the first forming unit 20A by the feed conveyor belt 15.

(2) The first forming unit 20A pulls the open pipe (work 1) conveyed by the feed conveyor belt 15 and delivers it to the second forming unit 20B while performing the first stage forming (reducing diameter).
The seam portion 2 is guided by the guide blade 5 while passing through the first forming portion 20A.
(3) The second forming unit 20B takes the open pipe (work 1) from the first forming unit 20A, pulls it in, and delivers it to the third forming unit 20C while performing the second-stage forming (diameter reduction).
While passing through the second forming part 20B, seam guide is performed by the guide roll 17 between the left and right wheels of the upper two-wheel roll 16B ′.
(4) The third forming portion 20C takes the open pipe from the second forming portion 20B, performs the third-stage forming, shapes the intermediate pipe material with the seam edge closely attached, and holds the short pipe Push into mechanism 10.
The seam portion 2 is not guided while passing through the third forming portion 20C.

(5) The short pipe holding mechanism 10 receives the intermediate pipe material (work 1) that has been shaped into a circular cross section by the third forming portion 20C and pushed out from the third forming portion 20C, and holds the circular pipe in a substantially circular shape. . The intermediate pipe material is pushed into the short pipe holding mechanism 10 by the third forming part 20C and goes straight through the short pipe holding mechanism, and the seam part 2 is welded with a torch to form a short pipe, toward the discharge mechanism 40. Extruded.
The distance from the entrance of the short tube holding mechanism 10 to the torch 9 is 138.5 mm, which is 61.5 mm shorter than the length of the workpiece 1 200 mm, and from the axial center of the drum roll 16C of the third forming portion 20C. The distance to the torch 9 is 188.5 mm, which is 11.5 mm shorter than the length of the intermediate pipe material (work 1) 200 mm. Therefore, when welding by the torch begins, the rear end of the intermediate pipe material is the third forming portion 20C. It does not deviate from the drum-shaped roll (third forming roll) 16C. After being removed from the drum-shaped roll 16C of the third forming portion 20C, the intermediate pipe material (work 1) is pushed by the subsequent intermediate pipe material (work 1) to advance the short tube holding mechanism 10.

(6) The intermediate pipe material (work 1) pushed out from the short tube holding mechanism 10 is held at the tip by the drum roll 13 of the discharge mechanism 40, and is drawn out and discharged from the short tube holding mechanism 10. Seam welding is not yet finished when the tip of the drum roll 13 is gripped, but thereafter, the remaining portion is seam welded while being pulled out at a constant speed.
The outer diameter of the discharged short pipe is approximately equal to the target outer diameter of 113.6 mm.

(7) Forming, etc. for the open pipe (work 1) The configuration of the embodiment is as described above, and the major axis of the cross section of the open pipe (work 1) thrown into the introduction path 3 of the introduction mechanism is about 116.5 mm. The forming process for this open pipe is as follows.
(A) The diameter is reduced to 115.3 mm by the first forming portion 20A and then reduced to 114.2 mm by the second forming portion 20B.
(B) Further, the diameter is reduced to 112.9 mm by the third forming portion 20C and shaped into a circular cross-section. At this stage, the seam end edges are brought into close contact to form an intermediate pipe member having a circular cross section, and are crushed by a minute amount in the radial direction. Note that the small amount of crushing of the intermediate pipe material in the radial direction in this way increases the gripping force by the drum-shaped roll (third forming roll) 16C of the third forming portion 20C and generates a sufficiently strong feeding force. This is because the intermediate pipe member (work 1) is smoothly pushed into the short tube holding mechanism 10.

(C) When the workpiece 1 is fed into the short tube holding mechanism 10, the diameter of the workpiece 1 is changed from 112.9 mm to 113.1 mm, and the above-mentioned small amount of collapse in the radial direction is restored by 0.2 mm, and the short tube is held. The outer periphery is held by many small-diameter rolls 11 of the mechanism 10.
(D) The outer diameter of the short pipe that is pushed out from the short pipe holding mechanism 10 to the discharge mechanism 40, gripped by the drum-shaped roll (discharge roll 13) of the discharge mechanism 40, and discharged by the discharge mechanism 40. Becomes 113.6 mm (target value).

(8) Workpiece feed speed The feed speed of the feed conveyor belt 15 of the introduction mechanism 30 is the fastest, and then the feed speed gradually increases in the order of the first forming section 20A, the second forming section 20B, and the third forming section 20C. ing. Therefore, the succeeding workpiece hits the preceding workpiece 1 (open pipe) in front of the first forming unit 20A, and thereafter, the succeeding workpiece pushes the preceding workpiece and is connected in a rosary manner to advance to the discharge roll. . Therefore, the feeding speed in the first forming unit 20A and the second forming unit 20B is slower than that in the third forming unit 20C (final shaping). Therefore, the first forming part 20A and the second forming part 20B cause slipping with respect to the work 1, but it is necessary to ensure the pressing force of the work 1 while exerting a biasing force in the feeding of the beads. These drum rolls 16A and 16B are made of urethane rubber. Accordingly, the drum rolls 16A and 16B are not limited to urethane rubber but may be made of steel or the like as long as the above action is exhibited.
The advance speed of the intermediate pipe material in the short pipe holding mechanism 10 is the same as the feed speed of the drum roll 16C of the third forming portion 20C and is constant. Since the feeding speed of the drum roll 13 of the discharge mechanism 40 is the same as that of the drum roll (third forming roll) 16C of the third forming portion, the workpiece 1 is also taken when it is taken up by the discharge roll 13 of the discharge mechanism 40. The forward speed in the short tube holding mechanism 10 does not change. Therefore, the welding speed in the torch 9 is constant, and the seam portion 2 can be welded cleanly without unevenness.
Even when seam welding is performed with the same torch 9, the workpiece feeding speed varies depending on the material and thickness of the workpiece 1, but is 0.6 ± 0.1 m / min in this embodiment.
[Modification]

About the introduction mechanism 30 The introduction mechanism 30 of the above-mentioned embodiment is of a system in which a work is manually inserted into the introduction part. The automatic mechanism in the prior art (Japanese Patent Laid-Open No. 55-247872) which is the basis of the invention of this application. A positioning mechanism can also be provided.

About the Forming Mechanism 20 In the embodiment, the forming mechanism 20 has a three-stage configuration of the first forming part 20A, the second forming part 20B, and the third forming part 20C, the front two stages are pre-forming means, and the third forming part 20C is The final shaping means is composed of four upper, lower, left and right hourglass rolls. The reason why the two-stage forming portion is configured as described above is to secure the formability close to a perfect circle. For example, when roll bending close to a perfect circle can be performed, the forming means is composed of one pre-form and final shape 1. A total of two stages can be used.
In addition, when a workpiece having a C-shaped cross section formed by bending, that is, when the outer diameter of the open pipe is close to the outer diameter of the target short pipe, the final shaping can be performed only by the one-stage forming portion by the third forming portion 20C. The pre-forming means (20A, 20B) can be omitted. However, in this case, it is necessary to devise the conveying means of the introducing portion so that the workpiece is gripped by the conveying means of the introducing portion and pushed into the final shaping means by the four hourglass rolls and pushed in the pressed state.

About the short tube holding mechanism 10 The short tube holding mechanism 10 of this embodiment has a large number of small cylindrical rolls 11 arranged on the inner surface of a single cylindrical casing 12, but a plurality of divided portions divided in the longitudinal direction. It can also be a type. For example, a central part having a base 81 having a welding opening 8, a front part up to the base 81, and a rear rear part from the base 81, preparing a plurality of front and rear parts having different lengths, By appropriately selecting and using according to the length of the workpiece 1, the entire length of the short tube holding mechanism 10 can be easily adjusted to be suitable for the length of the workpiece 1.
Further, in this embodiment, a cylindrical small-diameter roll 11 is disposed on the entire inner surface of the cylindrical casing 12, and the small-diameter roll 11 has an intermediate pipe material (work 1 before welding) and a short pipe (after welding) having a circular cross section. Although the outer peripheral surface of the workpiece 1) is uniformly pressed, this is to reduce the frictional resistance between the short pipe and the short pipe holding mechanism 10 as much as possible. In a case where the length is short and the frictional resistance is small, the structure can be simplified by changing some of the roller rows by the small-diameter rolls 11 in the axial direction to strip-like long blocks and reducing the number of roller rows. . In this case, the arrangement of the strip-like elongated blocks can be changed by avoiding the vicinity of the welding opening 8 and arranging, for example, one elongated block every two rows. In this case, it is desirable to reduce the frictional resistance by coating the work support surface of the elongated block (the surface on which the work 1 slides) with a heat-resistant, low-friction resin or the like.

In addition, a row of many hemispherical protrusions can be used instead of the elongated block, and a row of balls that are rotatably fitted in the pockets can be used. In the case of using a ball train, if a small ball is interposed at the bottom of the pocket into which the ball is fitted, the rotational resistance in the ball pocket is reduced.
Furthermore, the small diameter roll 11 can be a barrel-shaped roll. If a barrel-shaped roll is used, the number of rolls per set of annular rolls in which the small-diameter rolls 11 are arranged in an annular shape can be reduced, and the small-diameter roll 11 does not damage the surface of the workpiece 1 as compared with that of a cylindrical roll. . However, barrel rolls are worn heavily due to differential friction. In this case, it is necessary to take measures to reduce frictional resistance and wear, such as coating barrel rolls with heat-resistant and wear-resistant resin. is there.

About the discharge mechanism 40 The reason why the discharge mechanism 40 by the four drum-shaped discharge rolls 13 is provided is to pull out from the short tube holding mechanism 10 while holding the entire outer periphery of the short tube evenly immediately after welding. If there is no hindrance from the viewpoint of improvement, the discharge mechanism 40 using a pair of left and right drum rolls can be used, and the discharge mechanism 40 can be saved in some cases.

These are the top views of the whole external appearance of an Example. These are the front views of the whole external appearance of an Example. These are the principal part expansion external views of an Example. These are principal part sectional drawings of an Example. These are AA sectional drawings in FIG. These are BB sectional drawings in FIG. These are CC sectional drawing in FIG. These are DD sectional drawings in FIG. FIG. 5 is an EE cross-sectional view in FIG. 4. FIG. 5 is a sectional view taken along line FF in FIG. 4. These are GG sectional drawing in FIG. 4, and HH sectional drawing. These are II sectional drawings in FIG. These are the typical top views of a prior art example. These are the typical front views of a prior art example.

Explanation of symbols

1: Work 3: Introduction part 4: Side plate 5: Guide blade 8: Opening part 9: Torch 10: Single tube holding mechanism 11: Small diameter roll 12: Cylindrical casing 13: Discharge roll 15: Feed conveyor belt 16C: Final shaping roll 17: guide roller 20: forming mechanism 20A: first forming part 20B: second forming part 20C: third forming part 30: introduction mechanism 40: discharge mechanism

Claims (3)

A short pipe seam welding device in which a short pipe holding mechanism is arranged adjacent to the final shaping means by a drum roll,
A large number of small diameter rolls are annularly arranged on the inner surface of the cylindrical casing, and these small diameter rolls are arranged in parallel with the axis of the cylindrical casing to constitute a short tube holding mechanism,
The circumscribed circle diameter of the small diameter roll is slightly smaller than the outer diameter of the intermediate pipe material,
There is a seam welding window hole in the cylindrical casing,
The final shaping means is configured by four drum rolls on the top, bottom, left and right,
The diameter of the ring of the annular shaping surface by the arc-shaped roll surface of the four upper, lower, left and right drum-shaped rolls is slightly smaller than the outer diameter of the intermediate pipe material,
By the final shaping means, the workpiece is finally shaped into an intermediate pipe material with a seam edge abutted against it, and this is pushed into the short pipe holding mechanism,
A short pipe seam welding device that performs seam welding at the center in the longitudinal direction of the short pipe holding mechanism. A short pipe seam welding device in which a short pipe holding mechanism is arranged adjacent to the final shaping means by the drum-shaped roll, and a discharging means by the drum-shaped roll is arranged adjacent to the discharge end of the short pipe holding mechanism,
A large number of small diameter rolls are annularly arranged on the inner surface of the cylindrical casing, and these small diameter rolls are arranged in parallel with the axis of the cylindrical casing to constitute a short tube holding mechanism,
The circumscribed circle diameter of the small diameter roll is slightly smaller than the outer diameter of the intermediate pipe material,
There is a seam welding window hole in the cylindrical casing,
The final shaping means is configured by four drum rolls on the top, bottom, left and right,
The diameter of the ring of the annular shaping surface by the arc-shaped roll surface of the four upper, lower, left and right drum-shaped rolls is slightly smaller than the outer diameter of the intermediate pipe material,
The four drum rolls on the top, bottom, left and right constitute the discharge means,
The ring diameter of the annular surface by the roll surfaces of the four upper, lower, left and right drum-shaped rolls is slightly smaller than the outer diameter of the short pipe,
The feeding speed of the discharging means is the same as the feeding speed of the final shaping means,
The final shaping means final shapes the workpiece into an intermediate pipe material with the seam edge abutted against it, and pushes it into the short tube holding mechanism,
A short pipe seam welding apparatus that performs seam welding at a central portion in the longitudinal direction of a short pipe holding mechanism, and draws and discharges a workpiece from the short pipe holding mechanism by a discharging means. A short tube holding mechanism is arranged adjacent to the final shaping means by the drum type roll of the forming mechanism, and a discharging means by the drum type roll is arranged adjacent to the discharge end of the short pipe holding mechanism, and a work introduction mechanism is provided. A short pipe seam welding method for welding short pipes with a short pipe seam welding apparatus,
The work is fed into the forming mechanism while seam guiding at the work introduction part.
The workpiece is finally shaped into an intermediate pipe material by the final shaping means using the drum-shaped roll of the forming mechanism,
Push the intermediate pipe material into the short pipe holding mechanism by the final shaping means,
Hold the outer peripheral surface of the intermediate pipe material evenly clamped by the inner surface of the short tube holding mechanism, and go straight.
Seam welding at the center in the longitudinal direction of the short tube holding mechanism,
Advance while holding the short pipe seam welded by the short pipe holding mechanism inside,
A short pipe seam welding method in which a short pipe is gripped by the drum roll of the discharge means and pulled out from the short pipe holding mechanism and discharged.

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