JPH11179548A - Welding torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly feed a welding wire by bending the welding wire in the direction parallel to an axial center of a welding tip, straightening the wire leaving a wire bending part which is constituted of many guide rollers with a straightened and providing a pulling roller which pulls the wire and feeds it to the welding tip. SOLUTION: The welding wire 2 is bent downward at the sire bending part 13 which is constituted of eight outer guide rollers 15 and seen inner guide rollers 17, and a bending tendency of the welding wire 2 which is imparted by a straightening roller 19 at the wire bending part 13 is bent in the opposite direction to straighten it. The welding wire 2 which is pressed to the pulling roller 25 is drawn out of the wire bending part 13 with a pressing roller 22 and is fed to a groove of a pipe 5 through the welding tip 37 from a shielding gas nozzle 35. A shielding gas is fed from a shielding gas feeding part. Thus, frictional force is remarkably reduced by the outer and inner guide rollers 15, 17 in the wire bending part 13, the buckling of the welding wire 2 is prevented b a pulling system, and the wire is smoothly fed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding torch for a welding head of an automatic pipe circumference welding device or the like. In particular, the present invention relates to a welding torch that can reduce the height of a welding head and smoothly feed a welding wire.

[0002]

2. Description of the Related Art In a welding head having a mechanism for automatically sending a welding wire to a welding torch via a conduit cable, there are two systems for wire feeding from a wire reel to a welding torch. There is. One is a push method, and the other is a pull method. In the push method, after correcting the wire loosened from the reel, the wire is pushed into the conduit cable by a push roller in front of the conduit cable. In the pull method, a pull roller is attached to the welding torch on the outlet side of the conduit cable, and a wire in the conduit cable is pulled.

In the push method, the structure of the torch is simple and small and light, but the wire is easily buckled in the conduit cable, so that the wire is not easily fed smoothly. On the contrary, the pull method has a complicated structure of the torch, which tends to be heavy.

[0004] Incidentally, it has been pointed out that the impaired smoothness of the wire supply causes arc instability, turbulence in the molten pool, etc., leading to various welding defects (Journal of the Japan Welding Society, Vol. 41, No. 9, 1055
~). Therefore, further improvement of the wire feeding mechanism is required to stably perform high-quality welding. Especially,
The friction between the wire and the cable in the radius portion of the conduit cable is large, and when the radius is reduced, the friction suddenly becomes remarkable.

[0005] In the case of a pipe circumference automatic welding apparatus for pipelines of city gas or the like to be laid in a tunnel, it is required to minimize the height of the welding head. The diameter of the tunnel to be excavated for pipe laying is specified by the value obtained by adding twice the height of the welding head to the diameter of the pipe. To reduce construction costs, the diameter of the tunnel should be as small as possible. It is necessary to do it.

When trying to lower the height of the welding head,
It is necessary to reduce the radius of the wire bend at the entrance to the welding torch. The welding torch is basically perpendicular to the outer circumference of the pipe, but this is not possible if the wire supply reel is located directly above the torch, because the height of the welding head is significantly increased. Therefore, it is necessary to supply a wire guided from a reel placed somewhere else while bending it to a welding head standing at right angles to the outer peripheral surface of the pipe. The dimension obtained by adding the length of the torch to the radius of the wire bending portion is a dimension directly defining the height of the welding head. Therefore, the radius of the conduit cable at the wire bending portion is to be made as small as possible. However, if this is done, the friction of the wire in the conduit cable becomes extremely large as described above, which becomes a factor that hinders smooth wire feeding. Thus, reducing the height of the welding head and improving the smoothness of the wire feed are themes involving conflicting factors.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a welding torch which can reduce the height of a welding head and can smoothly feed a welding wire. In particular, it is an object of the present invention to provide an automatic pipe circumference welding device that can reduce the space required for laying a pipeline and contribute to reducing the cost of laying a pipeline.

[0008]

In order to solve the above-mentioned problems, an automatic pipe circumference welding apparatus according to a first aspect of the present invention bends a supplied welding wire to bend in a direction along the axis of a welding tip. A wire bend, and a straightener that straightens the wire that has come out of the wire bend, and a pull roller that pulls the wire that has come out of the straightener and sends the wire to the welding tip.
It is characterized by comprising a number of guide rollers.

[0009] The pipe circumferential automatic welding apparatus according to the second aspect of the present invention is characterized in that a wire bending portion formed by a multiplicity of guide rollers configured to bend a supplied welding wire to bend in a direction along an axis of a welding tip. A pull roller disposed near the exit side of the wire bend and pulling the wire exiting the straightener and sending it to the welding tip; and a straightener for straightening the wire exiting the wire bend. It is characterized by doing.

That is, in the automatic pipe circumference welding apparatus of the present invention, since the wire bending portion is constituted by a large number of guide rollers, the friction becomes rolling friction and the frictional force can be significantly reduced. In addition, since the pull method is used, buckling of the welding wire in the conduit cable or at the bent portion of the wire can be prevented, and a smooth wire feed can be realized. As a result, it is possible to secure high welding quality by smooth wire feeding while keeping the height of the welding head low by reducing the radius of the wire bending portion.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially sectional front view of a welding torch according to an example of the first aspect of the present invention. FIG. 2 is a partial sectional side view of the welding torch of FIG. FIG. 3 is a detailed sectional view of a guide roller of the welding torch of FIG. FIG. 4 is a detailed sectional view of a pull roller of the welding torch of FIG. In the welding torch 1, the welding wire 2 supplied from the upper right conduit cable 3 is bent downward at the wire bending portion 13, passes through the straightening roller 19, the pull roller 25,
It protrudes downward from the welding tip 37.

The wire bending portion 13 has eight outer guide rollers 15-1 disposed along the outside of the wire bending path.
8 to 7 and seven inner guide rollers 17-1 to 17-7 arranged along the inside of the same path. Each of the rollers 15 and 17 is, as shown in FIGS.
Is rotatably supported by an upper frame 61 made of bakelite, which is an insulating material.

More specifically, as shown in FIG. 3, two bolts 6 are connected to the bakelite frame 61 in parallel in the lateral direction.
5, 67 are planted. On the outer periphery of the bolt 65, a spacer 69, a bearing 72
(Inner ring), the spacer 73 is extrapolated, and the bolt head 7
5 and a nut 62. On the other hand, bolt 67
A spacer 71 and a bearing 17 (inner ring) are externally inserted from the frame 61 side in order from a frame 61 side.
And nut 64. In addition, nut 62,
The end face of the cover 64 is hidden by a bakelite cap 63. The bakelite frame 61 insulates each roller. The cap 63 is for insulating the bolt and the nut.

The outer guide roller 15 is made of a material SK3 (surface hardened), is fixed to the outer ring of the bearing 72, and can rotate freely. The inner guide roller 17 uses the outer ring of the bearing as it is, and can also rotate freely. On the outer periphery of the outer guide roller 15, a groove 15a for guiding the wire 2 to the center is formed. It should be noted that only the outer guide roller 15-1 on the innermost side is a roller having no groove.

The straightening roller 19 has a pressing roller 22 and a pulling roller 2 immediately below the outermost guide roller 15-8.
5 is provided immediately above. The right outer peripheral surface of the straightening roller 19 projects slightly so as to push the wire 2 to the right, and straightens the bending of the wire attached at the wire bending portion 13 in the opposite direction. The correction roller 19 has a structure similar to that of the pressing roller 22 shown in FIG. 4 and is rotatably supported by a correction roller yoke 21d.

The amount of protrusion of the correction roller 19 can be adjusted by a correction roller adjustment mechanism 21. That is, the correction roller yoke 21d is connected to the block 21b.
The block 21b includes an adjustment bolt 21a and a spring 21c.
And the frame 20 of the bolt 21a
By changing the amount of tightening for
b, the left and right positions of the roller 19 can be adjusted via the yoke 21d.

The pull roller 25 is located immediately below the straightening roller 19 in opposition to the pressing roller 22. The pressing roller 22 presses the wire 2 against the pull roller 25, and the pull roller 25 is driven to rotate, and the wire 2
3 and plays a role of pushing into a welding tip 37 described later. The material of the pull roller 25 is SK3 (surface hardened).

First, the specific structure of the pressing roller 22 will be described. As shown in the lower part of FIG. 4, the pressing roller 22 is configured using a bearing, and the outer ring of the bearing serves as a roller that holds down the wire 2. An insulation collar 95 made of Bakelite is fitted to the inner ring of the bearing, and insulates between the wire 2 to which the welding voltage is applied and the frame 48 of the torch. The insulating collar 95 is supported by a forked yoke 23d via a shaft 93.

The pressing pressure of the pressing roller 22 can be adjusted by a pressing roller adjusting mechanism 23 shown in FIG.
That is, the pressing roller yoke 23d is connected to the block 23c, and the block 23c is urged rightward (toward the pull roller 25) by the spring 23b. Further, the left end of the spring 23b is pressed by the adjustment bolt 23a through the head of the pin 23e. here,
The pin 23e is guided to the block 23c. Therefore, when the bolt 23a is tightened into the frame 20, the head of the pin 23e advances to the right to push the spring 23b, and the spring 23b
Is contracted, and the pressing force on the pressing roller 22 via the block 23c and the yoke 23d increases.

Next, the detailed structure of the pull roller 25 will be described. As shown in FIG. 4, the pull roller 25 has a ring shape having a wire guiding groove 25a on the outer periphery. The inner circumference and left and right end surfaces of the pull roller 25 are surrounded by insulating collars 83 and 87 made of Bakelite. The insulating collar 87 has a perforated disk shape, is fitted on the outer periphery of the shaft 43, and is set on the right end surface of the pull roller 25 with a spring pin 85. The reason why the spring pins 85 are used in this set is to prevent the insulating collars 83 and 87 and the pull roller 25 from rotating.

The insulating collar 83 is in the form of a sleeve with a brim, and is in contact with the inner surface and the left end surface of the pull roller 25.
The inner surface of the insulating collar 83 is fitted to the outer periphery of the shaft 43, and the left end surface is a bearing 45 through a spacer 81.
Are positioned by the inner ring. Spring pins 89 and 91 are set between the insulating collar 83 and the shaft 43. The reason why the spring pin is used in this set is the same as that of the spring pin 85 described above.

Next, the drive mechanism of the pull roller will be described. As shown in FIG.
Reference numeral 3 extends leftward, is held by two bearings 45, and is connected to a gear 47 at the left end. The gear 47 meshes with a lower gear 49. The gear 49 is further connected to another shaft 51. The shaft 51 is provided with a torch arm 5 extending leftward.
3 and extends to a pull roller drive servomotor (not shown). Therefore, the pull roller 25 is driven to rotate at an arbitrary number of rotations. The gears 49 and 47 have the same number of teeth and are not for deceleration but for offsetting the position of the shaft. Reference numeral 41 connected to the right end of the shaft 43 is a manual rotation knob for wire initialization and gear adjustment.

The wire 2 that has exited the pull roller 25 enters the shield gas nozzle 35 from the funnel opening 26, and protrudes downward through the welding tip 37 at the lower end of the nozzle.
It is supplied into the groove 6 of the pipe 5. A shield gas passage 36 is formed between the nozzle 35 and the tip 37,
As shown in FIG. 1, the shielding gas is supplied from the shielding gas supply unit 33 to the periphery of the protruding wire 2 along the path indicated by the arrow in the figure. Reference numeral 28 in the figure denotes a frame that supports the shield gas nozzle 35. Reference numeral 31 denotes a power supply unit that supplies a welding current to the wire 2.

The features of the first embodiment shown in FIGS. 1 to 4 are as follows. The wire bending portion 13 is formed of a roller row, and even if the bending radius of the welding wire is small (R = 30 mm in this example, the wire diameter is 1 mm), the frictional resistance is small. Since the wire is pulled and driven by the pull roller 25 on the exit side of the wire bending portion 13, the wire feeding is smooth, and the wire feeding to the welding pond is stabilized.

The amount of protrusion of the correction roller is made variable so that straightness of the wire can be guaranteed even when the wire diameter or the like changes. Even when the length of the wire protruding from the tip is 30 mm, the total height of the torch is 208 mm, which is considerably lower than the conventional one. Since there is no wire bending portion after the feeding roller and the correction roller, the straightness of the wire is improved.

FIG. 5 is a partially sectional front view of a welding torch according to an embodiment of the second aspect of the present invention. FIG. 6 is a side sectional view showing details of a guide roller of the welding torch of FIG. In the figure, the parts of the reference numerals obtained by adding 100 to the reference numerals of FIGS. 1 to 4 are the same parts as those of the welding torch of FIGS.

The features of the welding torch of this embodiment are as follows. (1) The pull roller 125 and the pressing roller 122 are provided in the wire bending portion 113. That is, the pull roller 125 is provided alongside the inner guide roller 117 of the wire bending portion 113. On the entry side of the pull roller 125, three inner guide rollers 117-
1, 2 and 3 have one inner guide roller 117- on the output side.
4 are arranged. Similarly, the pressing roller 122 is provided alongside the outer guide roller 113. On the entry side of the holding roller 122, five outer guide rollers 115-1 to 115-1 are provided.
5 and two outer guide rollers 115-6 and 7 are arranged on the delivery side. The diameter of each guide roller and holding roller is about 8 mm, and the diameter of the pull roller is about 20 mm. With this configuration, the height of the torch 101 is suppressed to 136 mm even when the wire protrudes 30 mm, which is even lower than that of the embodiment of FIG. However, pull roller 1
25, three guide rollers and a straightening roller 11
9, since the final guide rollers 120-1 and 120-2 on the exit side are present, a push-type color appears in the wire feed, and the fluctuation of the wire feed speed may be slightly increased.

(2) Each guide roller 115, 117
Grooves 115a and 117a are provided inside and outside.

(3) Two nozzles 133-1 and 133-1 for supplying a shielding gas are arranged on the left and right of the welding tip 137. Compared with the system in which the shield gas nozzle surrounds the outer periphery of the welding tip as in the embodiment of FIG. 1 and the shield gas is supplied to the entire periphery of the wire, the system as in the present embodiment has There is a disadvantage that the shielding property is insufficient, but on the other hand, there is an advantage that it can cope with a narrow groove.

(4) The power supply cable 130 is directed toward the power supply section 131 at an acute angle from above. This is to avoid interference with the shield gas nozzle. Note that reference numeral 1 in FIG.
32 is a power supply terminal for power supply, 134 is a tip body adapter for power supply and guides the welding wire, and 136 is processed into a conical shape for guiding the welding wire.

(5) The configuration of the insulation is different from that of the embodiment of FIG. On the entry side of the wire bending portion 113, the insulating block 112
Accordingly, the frame 114 of the wire bending portion 113 is insulated by the insulating plate 128 on the wire bending portion exit side. As shown in FIG. 6, the guide rollers 115 and 117 are insulated from the wire bending frame 114 by insulating collars 169 and 171 fitted between the set bolts 165 and 167 and the bearing inner ring. This is because the wire bending portion 113 includes the pull roller 125 and requires strength, so that it cannot be made of bakelite as in the embodiment of FIG. 1 and has to be made of steel.

(6) A pulse generator (PG) for detecting the wire feeding speed is provided on the pressing roller 122. For this reason, the wire feed amount and the wire protrusion amount from the welding tip at the time of non-arc can be accurately detected.

The embodiment described above can be modified or added as follows. (1) The frictional resistance can be reduced as much as possible by arranging the guide roller position on the clothoid curve. (2) The roller diameter and roller position can be adjusted depending on the welding wire diameter and material. (3) A guide for sending out the welding wire first can also be provided.

[0034]

As is clear from the above description, in the automatic pipe circumference welding apparatus of the present invention, since the wire bending portion is constituted by a number of guide rollers, the friction becomes rolling friction and the frictional force is significantly reduced. can do. In addition, since the pull method is used, buckling of the welding wire in the conduit cable or at the bent portion of the wire can be prevented, and a smooth wire feed can be realized. Therefore, it is possible to secure high welding quality by smooth wire feed while keeping the height of the welding head low by reducing the radius of the wire bending portion.
As a result, the space required for laying the pipeline can be reduced, which can contribute to reducing the cost of laying the pipeline.

[Brief description of the drawings]

FIG. 1 is a partially sectional front view of a welding torch according to an example of the first aspect of the present invention.

FIG. 2 is a partial cross-sectional side view of the welding torch of FIG.

FIG. 3 is a detailed sectional view of a guide roller of the welding torch of FIG. 1;

FIG. 4 is a detailed sectional view of a pull roller of the welding torch of FIG. 1;

FIG. 5 is a partially sectional front view of a welding torch according to an example of the second aspect of the present invention.

FIG. 6 is a side sectional view showing details of a guide roller of the welding torch of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Welding torch 2 Welding wire 3 Conduit cable 5 Pipe 6 Weld groove 11 Flexible joint 13 Wire bending part 15 Outer guide roller 17 Inner guide roller 19 Straightening roller 20 Frame 21 Straightening roller adjustment mechanism 22 Pressing roller 23 Pressing roller adjusting mechanism 25 Pull roller 26 funnel opening 27 frame 28 frame 31 feeder 33 shield gas supply 35 shield gas nozzle 36 shield gas passage 37 welding tip 41 43 shaft 45 bearing 47, 49 gear 48 frame 51 shaft 53 torch arm 61 frame 62, 64 nut 63 cap 65, 67 bolt 69, 71, 73 spacer 72 bearing 75, 77 bolt head 81 spacer 83, 87, 95 insulating collar 85, 89, 91
Spring pin 93 shaft 112 insulating block 114 frame 128 insulating plate 165,167
Set bolt 169, 171 Insulated collar

Claims (6)

[Claims] 1. A wire bending portion for bending a supplied welding wire to bend in a direction along the axis of a welding tip, a straightener for straightening a wire coming out of the wire bending portion, A pull roller for pulling out the output wire and feeding the wire to the welding tip, wherein the wire bending portion is constituted by a number of guide rollers. 2. The welding according to claim 1, wherein the guide roller comprises a combination of an inner guide roller arranged along the inside of the wire bending path and an outer guide roller arranged along the outside. torch. 3. A wire guide groove is formed on the outer periphery of said outer guide roller.
The described welding torch. 4. A wire bending portion formed by a multiplicity of guide rollers configured to bend a supplied welding wire in a direction along an axis of a welding tip, and a wire bending portion disposed near the exit side of the wire bending portion. A welding torch comprising: a pull roller that pulls a wire that has exited a straightener and feeds it to a welding tip; and a straightener that straightens the wire that has exited the bent portion of the wire. 5. The welding according to claim 4, wherein the guide roller comprises a combination of an inner guide roller arranged along the inside of the wire bending path and an outer guide roller arranged along the outside. torch. 6. The welding torch according to claim 5, wherein grooves for guiding the wire are formed on the outer periphery of the outer guide roller and the inner guide roller.