JP2672238B2 - Transformer for welding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for a welding machine, and more particularly to a transformer for a welding machine which is small in size, excellent in space efficiency, less affected by a leakage magnetic field to the outside, and excellent in maintainability. .

[0002]

2. Description of the Related Art In the industry, an inverter type DC resistance welding machine is widely used for welding various works. This type of welding machine is configured to perform a predetermined welding operation, for example, by attaching a transformer portion including a rectifier and a welding tip to the tip of a robot arm.

In this case, reduction in size and weight of the transformer portion including the rectifier is an important requirement from the viewpoint of speeding up the welding robot itself and improving productivity. For that purpose, it is important to reduce the size of each component and at the same time to arrange them.

For example, conventionally, there has been a transformer main body in which two to four diodes are arranged in a plane. However, as long as such an arranging method is adopted, it is difficult to make the area occupied by the rectifier 2 to 4 times or less the area of each diode. Since the area of each diode is determined from the output current capacity of the transformer, there is a limit to downsizing the entire transformer including such a rectifier.

Further, in such a transformer for a welding machine, maintainability is an important evaluation item. Among them, the diode is a component whose maintenance frequency is relatively high. Conventionally, there has been an attempt to improve maintainability by arranging this on the front surface of the transformer main body as described above. However, the method of disassembling and repairing the diode while it is attached to the transformer cannot solve the problem that the down time of the robot device increases.

Further, generally, in a transformer for a welding machine, an extremely large current flows through a secondary circuit, for example, each end conductor at the beginning and end of winding of a secondary coil, or a center tap output conductor. Therefore, there is a phenomenon in which the magnetic field induced by the current acts on a power cable or the like running near the transformer to generate unnecessary force or vibration. Since such a phenomenon may interfere with the welding operation of the robot and the operation of other peripheral devices, it is desirable to eliminate it as much as possible.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in a DC resistance welding machine transformer which rectifies a high frequency current induced in a secondary coil and supplies it as a DC welding current between welding tips. Compact and space efficient,
It is an object of the present invention to provide a transformer for a welding machine, which is less affected by a leakage magnetic field to the outside and has excellent maintainability.

[0008]

In order to achieve the above object, a transformer for a welding machine according to the present invention is provided with a center tap.
At the winding start and winding end of the secondary coil
Through each rectifier frequency current induced in the output terminals that
In the transformer for DC welding machine , which performs full-wave rectification and supplies DC welding current between welding tips ,
Between the center tap and each output end in parallel
Configured plurality of coils is characterized that you have provided integrally.

The welding machine transformer according to the present invention is
Each of the plurality of coils configured in parallel has
From one of the two ends, the output branches in parallel and
A plurality of first coils connected to the center tap;
Branch from the tap tap and extend in parallel to connect to the other output
And a plurality of second coils that are
Each coil constituting the first coil and the plurality of second coils
The coils that make up the
It is characterized by having been done.

Further, the transformer for a welding machine according to the present invention comprises: a coil for forming a plurality of first coils;
A number of second coils are alternately arranged.
Each first coil of the secondary coil configured to
And one coil so as to sandwich each coil of each second coil.
The following coil characterized that you have constructed are disposed by dividing.

Furthermore, the transformer for the welding machine according to the present invention is
In the secondary coil, the center tap and the
Two coils arranged in parallel are connected between each output terminal.
It characterized that you have provided the body manner.

Furthermore, in the transformer for a welding machine according to the present invention, a passage for a cooling medium is provided in the secondary coil.
And wherein the Tei Rukoto.

[0013]

In the transformer for a welding machine according to the present invention, the current induced in the secondary coil by the high frequency current flowing in the primary coil is rectified via the diode and supplied as a direct current between the welding tips.

In this case, the secondary coil has the sensor
Between the data tap and each of the output terminals described above.
The number of coils is integrally provided. With this configuration
Therefore, there is little leakage flux during driving,
The coupling rate between the secondary coils is extremely high. Therefore, the secondary coil
The rise time of the DC welding current generated in the
It becomes As a result, the frequency of the DC current on the primary coil side
Can be set higher, which gives higher output
Along with being able to reduce the core cross-sectional area,
It is possible to provide a lightweight transformer for a welding machine.

[0015]

[0016]

[0017]

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A transformer for a welding machine according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows the overall structure of a DC resistance welding apparatus to which the transformer for a welding machine of this embodiment is applied. This welding apparatus includes an AC power supply 10, a converter circuit 12 that generates a DC current from this AC current, an inverter circuit 14 that converts this DC current into a high frequency current, and a rectifier that converts this high frequency current into a DC current. Transformer for welding machine 1
6 and a welded portion 18 for welding the works W1 and W2 based on the DC current.

In this case, the welded portion 18 is a pair of gun arms 20a and 20b which can be moved to a predetermined portion of the works W1 and W2 by a robot (not shown), and a welding tip attached to the tips of the gun arms 20a and 20b. 22
a and 22b.

Next, the construction of the welding machine transformer 16 will be described with reference to FIGS. 2, 3 and 5 and 6. 2 and 3 show the case where the diode surface of the rectifier is placed parallel to the secondary coil winding axis, and FIGS. 5 and 6 show the case where the diode surface is placed perpendicular to the secondary coil winding axis. Shows. Other configurations are the same.

In the transformer 16 for the welding machine, a conductive coil is formed by bending a belt-shaped conductive thin plate into a coil shape, and a conductive block body is formed in a coil shape so as to be magnetically coupled to the primary coil 24. The secondary coil 26, the cores 28a and 28b arranged along the magnetic paths of the primary coil 24 and the secondary coil 26 to form a magnetic circuit, and the rectifier assembly 30.

The primary coil 24 has coil portions 39a to 39h that circulate in the same direction, and the ends of the coil portions 39a and 39h are connected to the inverter circuit 14, respectively.

As shown in FIG. 3, the secondary coil 26 extends in parallel from one end portion where the conductor block 44 (first terminal portion) is formed, is then bent downward, and then is center tapped. Secondary coil 26 in which the two first coils 40a and 40b reaching the portion and the center tap portion are extended in parallel and then bent downward once, and then the conductor block 46 (third terminal portion) is formed. Second coils 4 reaching the other end of the
2a and 42b. The first coils 40a and 40b and the second coils 42a and 42b form a two-turn coil with two circuits connected in parallel and with a center tap.

From the center tap portion, the conductor block 4
8 (second terminal portion) projects. The conductor block 48 extends parallel to the conductor blocks 44 and 46 and at an equal distance from them, and is then pulled out to the left or right.

The side portion of the first coil 40a constituting the secondary coil 26, the space between the first coils 40a and 40b, and the first coil 40a
Between the coil 40b and the second coil 42a, and between the second coil 42
The coil portions 39a, 39b and 39c, 39 of the primary coil 24 are provided between a and 42b and on the side portion of the second coil 42b.
d, 39e, 39f, 39g, and 39h are mounted via an insulating spacer (not shown).

The rectifier assembly 30 includes two electrode plates 3
2 and 34, a pair of diodes D1 and D2 sandwiched between the electrode plates 32 and 34 so as to face each other, and a terminal plate 36 interposed between the diodes D1 and D2.
And a pressing means for pressing them together.

The pressing means is composed of two pressure plates 52, 52, disc springs 54, 54 inserted between the pressure plates 52, 52 and the electrode plates 32 and 34, respectively, and a tightening bolt 56.

The electrode plates 32 and 34 are electrically connected to conductor blocks 44 and 46, respectively. In this case, the electrode plates 32 and 34 are placed in parallel with the secondary coil winding axis in FIGS. 2 and 3, and the electrode plates 32 and 3 are placed in FIGS.
4 is placed perpendicular to the secondary coil winding axis. Further, one end of the terminal plate 36 projects to the outside and constitutes the positive and negative electrodes of the welding DC circuit together with the conductor block 48 projecting from the center tap portion.

In addition, the secondary coil 26 and the conductor block 4
4, 46, the electrode plates 32, 34, and the terminal plate 36 are respectively provided with cooling water passages 60 and 62, which are connected and communicate with each other at their binding surfaces, as shown by the alternate long and short dash lines in FIGS. 4 and 7. Have That is, entering from the electrode plate 34, the conductor block 46, the second coil 42a of the secondary coil 26,
42 b, the center tap portion, the first coils 40 a and 40 b of the secondary coil 26, and the conductor block 44, and then the electrode plate 34.
There are a cooling water passage 60 discharged from and a cooling water passage 62 coming in and out of the terminal board 36.

The welding machine transformer of this embodiment and the welding apparatus to which the transformer is applied are basically constructed as described above. Next, their function and effect will be explained.

First, the welding apparatus operates as follows (see FIG. 1). The AC current supplied from the AC power supply 10 is converted into a DC current by the converter circuit 12,
Next, it is converted into a high-frequency current in the inverter circuit 14. Then, this high frequency current is applied to the transformer 1 for the welding machine.
6 to the primary coil 24.

When a high frequency current flows through the primary coil 24,
A high frequency voltage is induced in the secondary coil 26 via the cores 28a and 28b. This high-frequency voltage is full-wave rectified by the diodes D1 and D2, and the first coils 40a, 40b or the second coil 42 are oscillated every half cycle of the high-frequency voltage.
gun arm 20 as a direct current flowing through a and 42b.
The workpieces W1 and W2 are supplied between the welding tips 22a and 22b via the welding tips 22a and 22b.

Here, in the welding machine transformer 16 applied to the above welding apparatus, the secondary coil 26 is constituted by the two first coils 40a, 40b and the second coils 42a, 42b arranged in parallel. And the first coil 4
0a, 40b or the second coils 42a, 42b are configured so that currents flow simultaneously, so that there is little leakage flux during driving, and the primary coil 24 and the secondary coil 2
The bond ratio between 6 is extremely high. Therefore, the rising time of the DC welding current generated in the secondary coil 26 is extremely short. As a result, the frequency of the direct current on the primary coil 24 side can be set to a high value, whereby a high output can be obtained, the core cross-sectional area can be reduced, and a compact and lightweight transformer 16 for a welding machine can be provided. You can

In this case, the pair of diodes D1 and D2 are opposed to each other through the two electrode plates 32 and 34 connected to the end conductor blocks 44 and 46 at the winding start and the winding end of the secondary coil 26, respectively. Since the two diodes are stacked three-dimensionally, the occupying area of the rectifier assembly 30 becomes a value close to ½ of the total area of the diodes.

Further, a part of the output conductor block 48 at the center tap portion of the secondary coil 26 is provided at each end conductor block 44, 46 at the winding start and winding end of the secondary coil 26.
Since they extend in parallel with each other, at least in a portion where these conductors are parallel to each other, each end conductor block 44, 4 of the winding start and winding end is provided every half cycle of the high frequency current.
A current having the same size and the opposite direction flows through either one of the 6 and the output conductor block 48 of the center tap portion.
Therefore, the magnetic fields generated by the currents flowing through the portions cancel each other out, and the effect of the magnetic field near the outside of the transformer is reduced.

Further, the rectifier assembly 3 in which the two electrode plates 32 and 34, the pair of diodes D1 and D2, and the inter-diode terminal plate 36 are integrally pressure-bonded by pressing means.
0 is detachably attached between the end conductor blocks 44 and 46, so that the rectifier assembly 30
If something goes wrong with the product, just remove it and replace it with a good one to complete the repair.

Further, the secondary coil 26 and each conductor 32,
Cooling water passages 60, 6 are provided inside the parts 34, 36, 44, 46.
2 is formed, and the Joule heat generated in the secondary coil and each conductor is discharged to the outside of the system by the cooling water flowing through the cooling water passages 60 and 62. As a result, the synergistic cumulative phenomenon of temperature and resistance is stopped, so that the cross-sectional area of the coil and each conductor portion can be reduced.

With the cooling of the secondary coil 26, the primary coil 24 arranged along the secondary coil 26.
Since it is also cooled, its resistance value is lowered, so that a high current can be easily obtained.

In the above embodiment, the first coil 4
0a, 40b and the second coils 42a, 42b are paired respectively, but are not limited to this, and two or more pairs may be used.

[0041]

According to the transformer for a welding machine of the present invention, the center tap and the winding start end and winding end end are respectively output.
Multiple coils, each configured in parallel, are integrated between the force ends.
The secondary coil provided in the. For this reason,
There is little leakage flux during driving, and the primary coil and secondary coil
The binding rate between the two is extremely high. Therefore, the secondary coil
DC welding current rise time is extremely short
Become. As a result, the frequency of the DC current on the primary coil side is increased.
Can be set to high output.
In addition to being able to reduce the core cross-sectional area, small and lightweight
It is possible to provide a transformer for a welding machine.

Further, as a result of adopting a configuration in which the magnetic fields generated by the currents flowing through the conductor portions cancel each other out,
The effect of the magnetic field near the outside of the transformer is reduced, and the influence of the leakage magnetic field to the outside is small.

[0043]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a DC resistance welding device to which a welding machine transformer according to the present invention is applied.

FIG. 2 is a configuration perspective view of a transformer for a welding machine according to the present invention, in which a diode surface is arranged in parallel with a secondary coil winding axis.

3 is an exploded perspective view of essential parts of the transformer for the welding machine shown in FIG. 2. FIG.

4 is an explanatory view of a cooling water passage of the transformer for the welding machine shown in FIG.

FIG. 5 is a configuration perspective view of a transformer for a welding machine according to the present invention, in which a diode surface is arranged perpendicularly to a secondary coil winding axis.

6 is an exploded perspective view of essential parts of the transformer for the welding machine shown in FIG.

7 is an explanatory diagram of a cooling water passage of the welding machine transformer shown in FIG. 6. FIG.

[Explanation of symbols]

 16 ... Transformer for welding machine 26 ... Secondary coil 30 ... Rectifier assembly 32, 34 ... Electrode plate 36 ... Terminal plate 40a, 40b ... First coil 42a, 42b of secondary coil ... Second coil 44, 46 of secondary coil … Secondary coil end conductor block 48… Secondary coil center tap part output conductor block D1, D2… Diode

Claims (5)

(57) [Claims] 1. A winding start of a secondary coil with a center tap.
In the transformer for the DC welding machine, which performs full-wave rectification of the high-frequency currents induced at the output ends , which are the ends and the winding end , through the rectifiers , and supplies it as DC welding current between the welding tips, the secondary coil is , The center tap and each output end
In between, a plurality of coils configured in parallel are integrally installed.
Vignetting optionally transformer welder according to claim Rukoto. 2. The transformer according to claim 1, wherein each of the plurality of coils arranged in parallel is connected to each of the outputs.
From one of the two ends, the output branches in parallel and
A plurality of first coils connected to the center tap;
Branch from the tap tap and extend in parallel to connect to the other output
Is composed of a plurality of second coils, each coil constituting the plurality of first coil and the plurality of
The coils forming the second coil are alternately arranged.
Configured have transformer welder, characterized in Rukoto as. 3. The transformer according to claim 2 , wherein the coils forming the plurality of first coils and the plurality of coils are formed.
The coils forming the second coil are alternately arranged.
Each of the first coil and the second coil configured as described above.
And the primary coil so that each coil of each second coil is sandwiched.
Yl transformer welder characterized that you have constructed are disposed by dividing. 4. A according to any one of claims 1 to third transformer, to the secondary coil, the output ends and the center tap
In between, two coils that are configured in parallel are installed integrally.
Vignetting optionally transformer welder according to claim Rukoto. 5. A transformer according to claim 1, wherein the secondary coil, the passage for cooling medium has is provided transformer welder according to claim Rukoto.