JPS6113178Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flash butt welding device that is equipped with two welding transformers and eliminates the imbalance of welding currents supplied from each welding transformer.

In normal flash butt welding machines, if one welding transformer cannot cover the welding current, two
A welding transformer for the stand is attached to the upper or lower part of the welding machine body to ensure the required welding current.

By the way, when two welding transformers are connected in parallel on the welding transformer side and welding current is supplied to the welding electrode through a common secondary conductor, the combined current of both welding transformers flows through the secondary conductor, so especially In a flash butt welding machine that handles a large current, the voltage drop caused by the impedance of the secondary conductor cannot be ignored, making it impossible to secure the required welding current.
Therefore, it is conceivable that the welding current supplied from each welding transformer is supplied from the welding transformer to the vicinity of the welding electrode via mutually independent secondary conductors, and the secondary conductors are connected in parallel in the vicinity of the welding electrode. . However, in the case where the welding transformer is installed at the top of the welding machine body, the welding electrode is attached to the tip of the clamp arm that clamps the workpiece, so there is flexibility between the welding transformer and the welding electrode. It is necessary to insert a conductor, for example, a flexible conductor made of a large number of laminated thin copper plates, and furthermore, secondary conductors including this flexible conductor must be connected to the welding electrode independently of each other. Therefore, there are a plurality of connections of the secondary conductors, and the lengths of the secondary conductors become non-uniform, causing a difference in the combined impedance of the secondary conductors in the welding circuit formed for each welding transformer. As a result, an imbalance occurs in the welding currents supplied from each welding transformer, and the utilization rate of the welding transformer with higher impedance decreases, while at the same time a large current flows into the welding transformer with lower impedance. There was also a risk of burning out the welding transformer on the side that carries the large current.

The present invention was developed in view of the above circumstances, and is a method for supplying welding current from two welding transformers via mutually independent secondary conductors to welding electrodes that clamp the butt ends of the workpiece. , the weight distribution as a welding device is good, and the composite impedance of the secondary conductor in the welding circuit formed for each welding transformer can be easily equalized, so that the welding power supplied from each welding transformer is An object of the present invention is to provide a flash butt welding device that can eliminate current imbalance.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In the figure, reference numeral 1 indicates a bed that constitutes the welding machine main body. A support base 2 is fixed to one side of the bed 1 via an insulating member 3, and an electrode receiving member 4 is protruded from the front surface of this support base 2. It is set up. A fixed lower electrode 5 is fixed to the upper end of the electrode receiving member 4 via bolts 6, and a wedge-shaped conductor 7 is inserted into the bottom surface of the fixed lower electrode 5. In addition, the support stand 2
A clamp arm 8 is rotatably attached to the top via a shaft 9, and an electrode support conductor 10 is fixed to one end of the clamp arm 8 via bolts 11. Then, a fixed side upper electrode 12 as a welding electrode is attached to the lower end of this electrode support conductor 10 with a bolt 13.
..., and one abutting end 14a of the workpiece 14 is clamped by the fixed upper electrode 12 and the fixed lower electrode 5. The clamp arm 8 is rotationally driven by a hydraulic cylinder 8a provided at the other end of the clamp arm 8.

Further, a wedge-shaped conductor 15 is inserted into the upper surface of the fixed-side upper electrode 12.

On the other hand, the fixed side upper and lower electrodes 1 are driven by a hydraulic cylinder (not shown) on a guide rail 16 provided on the bed 1 on the other side of the bed 1.
A movable table 17 that moves forward and backward in the 2nd and 5th directions is provided. Further, an electrode receiving member 18 is provided protruding from the front surface of the moving table 17, and the moving side lower electrode 19 is fixed to the upper end of the electrode receiving member 18 via bolts 20. A wedge-shaped conductor 21 is inserted in the bottom part. Further, a clamp arm 22 is rotatably mounted on the moving table 17 via a shaft 23, and the clamp arm 22
An electrode supporting conductor 24 is fixed to one end of the electrode via bolts 25. And this electrode support conductor 24
Moving side upper electrode 26 as a welding electrode at the lower end of
are fixed via bolts 27, and the other abutting end 14b of the workpiece 14 is clamped by the moving-side upper electrode 26 and the moving-side lower electrode 19. Note that the clamp arm 22
is rotationally driven by a hydraulic cylinder (not shown) provided at the other end of the clamp arm 22.

Further, a wedge-shaped conductor 28 is inserted into the upper surface of the moving-side upper electrode 26. Incidentally, welding transformers 30 and 31 having the same characteristics are arranged adjacent to each other above the clamp arms 8 and 22, respectively, with the front surfaces of both welding transformers 30 and 31 held flush.

Further, as shown in FIG. 3, the electrode supporting conductor 1
0 and 24 are symmetrical to each other, and a pair of branch conductor portions 10a, 10b and 24a, 24b integrally protrude from the proximal end side, each integrally formed in an L-shape. And the welding transformer 30
A rectangular conductor piece 33 with the bottom half cut out as shown in FIG. At the same time, the other ends of the flexible conductors 32, 32 are fixed to one branch conductor portion 10a of the electrode supporting conductor 10 with bolts 36... and pressers 37. , 37. Further, the other output terminal 30b of the welding transformer 30 is provided with a rectangular conductor base 38a with the latter half of the bottom portion cut out as shown in FIG. Extension portion 38 bent into a letter shape
The conductor base 38a side of the conductor piece 38 consisting of the conductor piece 38 is fixed via bolts 39. One end of the flexible conductors 40, 40 is fixed to the tip of the extending portion 38b via bolts 41... and pressers 42, 42, and the other end of the flexible conductor 40, 40 is connected to the electrode. One branch conductor portion 24 of the support conductor 24
a through bolts 43 and presser feet 44, 44.

On the other hand, as shown in FIG. 4c, one output terminal 31a of the welding transformer 31 has a symmetrical shape with respect to the conductor piece 38 in the front and rear, left and right directions, and the dimensions of each corresponding part are the same as that of the conductor base of the conductor piece 45. 45a
are fixed via bolts (not shown). One end of the flexible conductor 46, 46 is fixed to the tip of the extending portion 45b of the conductor piece 45 via a bolt and a presser foot, and the flexible conductor 46, 46
The other end portion is fixed to the other branch conductor portion 10b of the electrode support conductor 10 via bolts 47 and pressers 48, 48.

Also, one end of the flexible conductors 49, 49 is connected to the other output terminal 31b of the welding transformer 31 as shown in FIG.
As shown in FIG. 3, a conductor piece 50 which is symmetrical with the conductor piece 33 in front and rear and left and right directions and whose corresponding parts have the same dimensions is inserted and fixed via bolts and a presser. Flexible conductor 4
9, 49 to the other branch conductor portion 24b of the electrode support conductor 24 with bolts 51... and presser feet 52,
It is fixed via 52.

Note that the conductor pieces 33, 38, 45, and 50 are insulated from each other via insulating members 53, respectively. Further, the extending portions 38b of the conductor pieces 38, 45
and each flexible conductor 32, 40, 4 on the lower surface part of 45b.
6, 49, the insulating member 54...
is attached.

Further, the wedge-shaped conductors 7, 15, 21, 28
are adjustment bolts 7a, 15a, 21a, 28 screwed into these wedge-shaped conductors 7, 15, 21, 28.
Along with a, electrode position adjustment mechanisms 54, 55, 56,
57, each of the adjustment bolts 7a, 15a,
By rotating the wedge-shaped conductors 21a and 28a, the wedge-shaped conductors 7, 15, 21, and 28 are adjusted forward and backward, and the upper and lower fixed-side lower and upper electrodes 5 and 12 and the movable lower and upper electrodes 19 and 26 are The position is adjusted downward.

Further, a welding object pushing mechanism 60 is provided at the lower part of the bed 1 to automatically push out the welded object from the electrode after welding is completed. This workpiece extrusion mechanism 60
The push-out arm 62 is rotatably pivoted to a support member 61 protruding from the front frame 1a that supports the bed 1, and the extrusion arm 62 is arranged at the lower part of the bed 1, and the tip of the operating shaft 63a is connected to the It consists of a hydraulic cylinder 63 that is attached to the lower end of the extrusion arm 62 and rotates the extrusion arm 62, and the workpiece 14 is pushed out at the upper end of the extrusion arm 62 by the operation of this hydraulic cylinder 63. ing.

Here, it is formed on the secondary side of each of the welding transformers 30 and 31. The welding circuits 64 and 65 are represented as an equivalent circuit as shown in FIG. That is,
Secondary conductors 70 and 71 constituting the welding circuit 64 are a conductor piece 33 connecting one output terminal 30a of the welding transformer 30 and the fixed upper electrode 12, a flexible conductor 32, 32, and an electrode support conductor 10, respectively. One branch conductor portion 10a and the electrode support conductor 1
0, the conductor piece 38 connecting the other output terminal 30b of the welding transformer 30 and the moving side upper electrode 26, the flexible conductors 40, 40, one branch conductor part 24a of the electrode support conductor 24, and the electrode Support conductor 24
The impedance of the secondary conductor 70 is Z ₁ and the impedance of the secondary conductor 71 is Z ₂ .

Further, secondary conductors 72 and 73 constituting the welding circuit 65 are a conductor piece 38 connecting one output terminal 31a of the welding transformer 31 and the fixed side upper electrode 12, flexible conductors 46, 46, and electrodes, respectively. A conductor piece 50 connecting the other branch conductor portion 10b of the supporting conductor 10 and the base end portion of the electrode supporting conductor 10, the other output terminal 31b of the welding transformer 31, and the movable side upper electrode 26, and flexible conductors 49, 49 , the other branch conductor portion 24b of the electrode support conductor 24 and the base end portion of the electrode support conductor 24, and the impedance Z ₃ of the secondary conductor 72 and the impedance of the secondary conductor 73
Let's say Z ₄ .

Note that the dimensions of the corresponding parts of the branch conductor parts 10a, 10b and 24a, 24b of both the electrode supporting conductors 10 and 24 are made the same. Similarly, the dimensions of the corresponding parts of the flexible conductors 32, 40, 46, and 49 are made the same.

According to such a configuration, by arranging the two welding transformers 30, 31 symmetrically above the left and right fixed side and movable side upper electrodes 12, 26, the welding transformer 30 can be connected to the fixed side upper part. Electrode 1
2 and the distance from the welding transformer 31 to the movable-side upper electrode 26 can be made equal, and the output terminals 30a, 30b, 3 of each welding transformer 30, 31 can be made equal.
The shape of the conductor piece to be applied to 1a and 31b is 33,
As a result of matching 50 and 38 and 45, the internal impedances of 33 and 50 and 38 and 45 can be made equal, and furthermore, the left and right upper electrodes 12 and 2
The shapes and lengths of the electrode support conductors 10 and 24 hanging down from the two welding transformers 30 and 31
Since the internal impedances of 10 and 24 can be made equal by matching them due to the left-right symmetrical arrangement _of
and the impedance Z ₄ of the secondary conductor 73 on the welding circuit 65 side are equal to each other, and the impedance Z ₂ of the secondary conductor 71 on the welding circuit 64 side and the impedance Z ₃ of the secondary conductor 72 on the welding circuit 65 side are equal to each other. Therefore, the combined impedance of the secondary conductors 70 and 71 of the welding circuit 64 (Z ₁ +Z ₂ ) and the combined impedance of the secondary conductors 72 and 73 of the welding circuit 65 (Z ₃ +
Z ₄ ) become equal, and both welding transformers 30 and 31
The same welding current can always be supplied to the fixed side and movable side upper electrodes 12 and 26 from the above. Therefore, since both welding transformers 30 and 31 are always used under the same load condition, there is a risk that the utilization rate of one of the welding transformers will decrease or that an excessive current will flow through one of the welding transformers and cause it to burn out. This eliminates the welding current and allows the welding current to be drawn out to the sum of the rated currents of both welding transformers 30 and 31.

Furthermore, the left and right fixed side and movable side upper electrodes 1
Since the welding transformers 30 and 31 are arranged symmetrically above 2 and 26, the welding transformers 30 and 31
and secondary conductors 70 and 7 connecting upper electrodes 12 and 26
3 can be made to have the shortest distance, thereby making it possible to reduce the internal impedance of each of the secondary conductors 70 to 73 and prevent a decrease in welding current.

Further, as shown in FIG. 3, each output terminal 30a, 30b of one welding transformer 30 is connected to a conductor piece 33
38 to the flexible conductors 32 and 40, and the respective output terminals 31a, 31b of the other welding transformer 31 are connected to the conductor pieces 45 and 50 which are symmetrical in front and rear and left and right with the conductor pieces 38 and 33. The welding transformer 30 and 31
can be disposed at mutually symmetrical positions, that is, at mutually symmetrical positions with respect to a vertical line passing through the center of the welding machine main body, and the weight balance of the entire welding machine can be ensured.

Further, as shown in FIG. 3, the welding current flows alternately in the direction indicated by the arrow in the figure or in the opposite direction, but as in this embodiment, the welding current flows in the extending portion 3 of the conductor piece 38.
8b or the extending portion 45b of the conductor piece 45 is bent into a dogleg shape to form the flexible conductor 32, 40 or 46,4.
9, the magnetic flux generated in each conductor cancels each other out, and the impedance of the secondary conductor can be reduced. Similarly, each branch conductor portion 10a, 10b of the electrode supporting conductor 10 and 24
and 24a, 24b as flexible conductors 32, 46 and 4
0,49, the impedance of the secondary conductor can be reduced.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the present invention, Figure 2 is a front view showing one embodiment of the present invention;
3 is a perspective view of the secondary conductor of the same embodiment. FIGS. 4 a to d are perspective views of each conductor piece of the same embodiment. The figure is a welding circuit diagram of the same embodiment. 10, 24... Electrode support conductor, 12, 26...
Welding electrode, 14... Work to be welded, 14a, 14b...
...Butt end, 30, 31...Welding transformer, 3
0a, 30b, 31a, 31b...output terminal, 3
2, 40... Flexible conductor, 33, 38, 45, 50
...Conductor piece, 64,65...Welding circuit, 70,7
1, 72, 73...Secondary conductor.

Claims (1)

[Scope of utility model registration request] Welding electrodes that clamp both butt ends of the workpiece are connected to two welding transformers that are independent of each other.
In supplying welding current through the secondary conductor, the two welding transformers are placed symmetrically above the left and right upper electrodes of the welding electrodes, and a pair of welding transformers are installed on the bottom surface of these welding transformers. Similarly, place the output terminals side by side on the left and right, and apply a conductor piece to each output terminal from below.
In addition, extending portions are provided on the conductor piece adjacent to the mating welding transformer among the pair of conductor pieces of each welding transformer, respectively, at different positions in the front and back, and sneaking into the lower side of the pair of conductive pieces of the mating transformer by sandwiching an insulating member. These four conductor pieces are arranged in a symmetrical combination in the front and rear and left and right directions, and a pair of front and rear electrode support conductors are directed from the left and right upper electrodes to the welding transformer located directly above the respective upper electrodes. What is claimed is: 1. A flash butt welding device characterized in that the upper ends of these electrode supporting conductors are connected to corresponding conductor pieces or conductor piece extensions via flexible conductors.