JPH0780055B2 - Welding gun with transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is configured by arranging a plurality of transformers in one direction and connecting each electrode to a secondary coil and a center tap terminal plate of each transformer. Regarding welding gun with transformer.

[Prior Art] A transformer unit in which a rectifier is interposed at both ends of a secondary coil of a transformer is often used by incorporating it into a resistance welding apparatus. This type of resistance welding apparatus requires a relatively large current. Therefore, a large capacity is desired.

Therefore, in order to increase the capacity and reduce the size of the entire resistance welding apparatus, the present applicant has arranged a plurality of transformers in one direction, and terminal plates connected to each secondary coil via a rectifier, Proposed is a device configured to connect center tap terminal plates derived from an intermediate portion of the secondary coil to each other in an oriented direction of the transformer and to integrally connect a welding gun to an end portion thereof. (Japanese Patent Application 1-12
1832 gazette).

[Problems to be Solved by the Invention] Generally, when a plurality of transformers are arranged in one direction, the current value supplied from each transformer becomes different. Equivalently explaining this using FIG. 7, while the first terminal plate 2 and the second terminal plate 4 are connected to the secondary coils of the four transformers TR1 to TR4,
The first and second terminal plates 2, 4 are connected to the respective electrodes 6, 8 of the welding gun. Here, the resistor R is each transformer TR
1 to the transformer TR4 and the first and second terminal plates 2 and 4, the resistance is shown, the resistor RG is the resistance between the first and second terminal plates 2 and 4 and the electrodes 6 and 8, and the resistor RW is the electrode. The resistance due to the welded object between 6 and 8 is shown respectively.

Therefore, the currents I1 to I4 supplied from the transformers TR1 to TR4 satisfy the following expressions.

I1 = E / (6R + RW + 2RG) I2 = E / (4R + RW + 2RG) I3 = E / (2R + RW + 2RG) I4 = E / (RW + 2RG) As a result, I1 <I2 <I3 <I4. For this reason, the capacitance of each transformer TR1 to TR4 should be
If the number is set to 4, there is a problem that the other transformers TR1 to TR3 become larger than necessary and are not efficient. On the other hand, if each of the transformers TR1 to TR4 is selected to have a desired capacity, the maintenance management becomes complicated and it becomes extremely uneconomical.

The present invention solves this kind of problem by arranging a plurality of transformers in one direction and making the current value supplied from this transformer as uniform as possible without changing the capacitance of each transformer. It is an object of the present invention to provide a welding gun with a transformer that enables the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of transformers arranged in a predetermined direction and terminal plates connected to the secondary coils of each transformer. A first conductive plate oriented in the arrangement direction and integrally connected, and a second center tap terminal plate derived from an intermediate portion of the secondary coil, oriented in the arrangement direction and integrally connected A conductive plate, a first conductor having one end connected to one end portion in the arrangement direction of the first conductive plate and the other end connectable to one electrode, and one end of the other end of the second conductive plate in the arrangement direction A second conductor which is connected to the part and whose other end can be connected to the other electrode.

Further, according to the present invention, a plurality of transformers arranged in a predetermined direction and a plurality of transformers and terminal plates connected to the secondary coils of the transformers are oriented in the arrangement direction and integrally connected. A plate, a second conductive plate for integrally connecting the center tap terminal plates led out from the middle portion of the secondary coil in the array direction, and one end of the first conductive plate in the array direction of the first conductive plate. A first conductor which is connected to the intermediate part and whose other end is connectable to one of the electrodes; and a first conductor which connects one end to the middle part in the arrangement direction of the second conductive plate and the other end to the other electrode. 2 conductors are provided.

[Operation] In the welding gun with a transformer according to the present invention described above, one end portion in the arrangement direction of the first conductive plate that integrally connects the terminal plates connected to the secondary coils of each transformer in the arrangement direction. The first conductor is connected to the center conductor, and the center tap terminal plates led out from the intermediate portion of the secondary coil are oriented in the arrangement direction and are integrally connected to each other. The second conductor is connected to the end portion. Therefore, the resistance between each transformer and the electrode becomes uniform,
It is possible to prevent the current value supplied from each transformer from changing.

Furthermore, in the welding gun with a transformer according to the present invention, the first conductor is connected to the intermediate portion in the arrangement direction of the first conductive plate, while the second conductor is connected to the intermediate portion in the arrangement direction of the second conductive plate. , A current having a substantially uniform value is supplied from each transformer to the electrodes.

[Example] A welding gun with a transformer according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIGS. 1 and 2, reference numeral 10 indicates a welding gun with a transformer according to the first embodiment, and the welding gun 10 is rotatably supported by a holder 12. This holder 12
Includes a cylindrical member 16 suspended from the chain 14, and the cylindrical member 16 is displaceable in the arrow direction via a pulley or the like (not shown) engaged with the upper end side of the chain 14. The cylindrical member 16 is provided with a rotary cylinder 20 by guide rollers 18a to 18d.
Is held, and the welding gun 10 is held from four directions on the inner peripheral portion of the rotary cylinder 20 via the holding member 22.

The welding gun 10 includes a plurality of transformers arranged in a predetermined direction (arrow A direction) through a long casing 30.
32a to 32d and a first conductive plate 42 that integrally connects terminal plates 40a to 40d connected to the pair of secondary coils 38a to 38d of the transformers 32a to 32d, respectively, by orienting them in the arrangement direction. , A second conductive plate 46 for integrally connecting the center tap terminal plates 44a to 44d led out from the intermediate portion of the secondary coils 38a to 38d in the arrangement direction, and a first conductive plate at one end A first conductor 50 that is connected to one end portion in the arrangement direction of 42 and the other end is connectable to one electrode 48a, and one end is connected to the other end portion in the arrangement direction of the second conductive plate 46 and the other end is the other end. And a second conductor 51 that can be connected to the electrode 48b.

Secondary electrode plates 52a, 52a are attached to both ends of the secondary coils 38a, 38a, and an insulating material 54a is disposed between the secondary electrode plates 52a, 52a. Rectifiers 56a and 56a are provided on the secondary electrode plates 52a and 52a.
The terminal plate 40a is integrally arranged through the plate 58a made of an iron plate, the terminal plate 40a, and the secondary electrode plates 52a, 5a.
2a and 2a are fixed by bolting (see FIG. 3).

A connecting portion 60a connected to the first conductive plate 42 is provided at an end portion of the terminal plate 40a, while a first portion of the center tap terminal plate 44a led out from an intermediate portion of the secondary coils 38a, 38a is provided with a first portion. A connecting portion 62a connected to the two conductive plates 46 is provided.

Although the transformer 32a has been described in detail above, the other transformers 32b to 32d are configured in the same manner as this transformer 32a, and the same components are designated by the same reference numerals with the symbols b to d. Detailed description thereof will be omitted.

The first and second conductive plates 42, 46 have a long shape, are arranged in parallel with each other, and are integrally fixed via connecting bars 64a, 64b made of a non-conductive material. .

A bracket 70 is fixed to the casing 30, a fixed gun arm 72 is provided on the bracket 70, and a movable gun arm 74 is swingably supported via a cylinder 76. Fixed gun arm 72, movable gun arm 74, electrode 48
a and 48b are attached, the electrode 48a is connected to the first conductor 50 via the conductor 77 and the multilayer strip copper plate 78, and the electrode 48b is connected to the first conductor 50 via the conductor 80 and the multilayer strip copper plate 82. 2 connected to the conductor 51.

The welding gun with a transformer according to this embodiment is configured as described above, and its operation will be described below.

First, the welded portions of the _two workpieces W ₁ and W ₂ are overlapped, and the worker transfers the welding gun 10 through the holder 12 to the predetermined welded portions of the workpieces W ₁ and W _2. .

Next, the movable gun arm 74 is oscillated and displaced under the action of the cylinder 76, and the workpieces W ₁ and W ₂ are clamped by the electrodes 48b and 48a attached to the movable gun arm 74 and the fixed gun arm 72, and an alternating current (not shown) is applied. A high frequency alternating current is output under the driving action of the power supply. This high-frequency alternating current is applied to the transformer 32a.
To 32d from primary coils (not shown) to secondary coils 38a to 38d, and single-phase full-wave rectification is performed by rectifiers 56a to 56d connected to both ends of the secondary coils 38a to 38d. This rectified current is added to the first conductive plate 42 from the connection parts 60a to 60d of the terminal plates 40a to 40d. Therefore, the first conductor 50 fixed to the first conductive plate 42
An electrode 48a electrically connected to each other via a multilayer strip copper plate 78 and a conductor 77, and a second conductive plate 46 and a second conductive body 51 fixed to connecting portions 62a to 62d of the center tap terminal plates 44a to 44d. A welding current is supplied between the multilayer strip copper plate 82 and the electrode 48b electrically connected via the conductor 80. As a result, the welded parts of the works W ₁ and W ₂ are melted, and the desired parts of the works W ₁ and W ₂ are joined.

In this case, according to the present embodiment, the four transformers 32a to 3a
2d are arranged in the direction of arrow A, and terminal boards 40a to 40d
And the first and second center tap terminal plates 44a to 44d.
The conductive plates 42 and 46 are integrally connected, and the first
The first conductor 50 is connected to one end of the conductive plate 42 in the arrangement direction, while the second conductor 51 is connected to the other end of the second conductive plate 46 in the arrangement direction. Therefore, there is an effect that the current values supplied from the transformers 32a to 32d are made as uniform as possible.

That is, the transformers 32a to 32d and the electrodes in this embodiment are
The connection state with 48a and 48b is equivalently shown in FIG. 4 corresponding to the conventional connection state shown in FIG. Accordingly, it can be considered that the resistors (3R + 2RG + RW) having the same value exist between the transformers 32a to 32d and the electrodes 48a and 48b. Therefore, the transformers 32a to 32d supply the current I having the same value shown in the following equation.

I = E / (3R + 2RG + RW) Therefore, it is possible to make the capacities of the transformers 32a to 32d the same, and for example, it is very economical compared to the case where the transformers 32a to 32d have different capacities. The effect that there is is obtained. Moreover, the transformer
32a to 32d can be efficiently used, the size can be reduced, and the overall weight and size of the welding gun 10 can be easily reduced.

Next, a welding gun with a transformer according to a second embodiment of the present invention is shown in FIGS. The same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In this case, the welding gun with transformer 100 according to the second embodiment
Now, one end of the first conductor 102 is connectable at one end to an intermediate portion in the arrangement direction of the first conductive plate 42 and at the other end is connectable to the one electrode 48a.
And a second conductor 104, one end of which is connected to an intermediate portion of the second conductive plate 46 in the arrangement direction and the other end of which is connectable to the other electrode 48b.

Therefore, as can be seen from FIG. 6, the transformer 32
Currents Ia and Ib shown below are supplied from a and 32d and transformers 32b and 32c, respectively.

Ia = E / (3R + 2RG + RW) Ib = E / (R + 2RG + RW) As a result, the transformers 32a to 32d can be set to the same capacity, and the same effect as the transformer welding gun 10 according to the first embodiment can be obtained. .

[Effects of the Invention] As described above, in the welding gun with a transformer according to the present invention,
It has the following effects and advantages.

The first conductor is connected to one end portion in the arrangement direction of the first conductive plate that connects the terminal plates connected to the secondary coil of each transformer together in the arrangement direction, and the second conductor is connected to the secondary conductor. A second structure in which center tap terminal plates led out from an intermediate portion of the coil are oriented in the arrangement direction and integrally connected.
The second conductor is connected to the other end portion of the conductive plate in the arrangement direction. Therefore, the resistance between each transformer and the electrode becomes uniform, and it is possible to prevent the current value supplied from each transformer from fluctuating. Therefore, a transformer with the same capacity is used to efficiently supply a large current. It will be possible. Moreover, the transformer does not become unnecessarily large, and the overall weight and size of the welding gun can be easily reduced.

Further, in the welding gun with a transformer according to the present invention, the first conductor is connected to the intermediate portion in the arrangement direction of the first conductive plate, while the second conductor is connected to the intermediate portion in the arrangement direction of the second conductive plate. A current having a substantially uniform value is supplied from each transformer to the electrodes. This enables efficient use of the transformer.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of a welding gun with a transformer according to a first embodiment of the present invention mounted on a holder, FIG. 2 is a front view of the welding gun with a part thereof omitted, and FIG. 3 is the welding gun. 4 is a partial side view, FIG. 4 is a schematic connection diagram showing a connection state equivalent to the welding gun, and FIG. 5 is a state in which the welding gun with a transformer according to the second embodiment of the present invention is attached to a holder. A partially omitted front view, FIG. 6 is a schematic connection diagram showing a connection state equivalent to that of the welding gun shown in FIG. 5, and FIG. 7 is a schematic connection diagram showing a connection state of a conventional welding gun. 10 …… Welding gun 12 …… Holder 32a ～ 32d …… Transformer 38a ～ 38d …… Secondary coil 40a ～ 40d …… Terminal plate 42 …… Conductive plate 44a ～ 44d …… Center tap terminal plate 46 …… Conductive plate 48a , 48b ... Electrodes 50, 51 ... Conductors 52a to 52d ... Secondary electrode plates

Claims (2)

[Claims] 1. A first conductive device for integrally connecting a plurality of transformers arranged in a predetermined direction and terminal plates connected to secondary coils of the transformers in the arranged direction. A plate, a second conductive plate for integrally connecting the center tap terminal plates led out from the middle portion of the secondary coil in the array direction, and one end of the first conductive plate in the array direction of the first conductive plate. A first conductor that is connected to one end portion and the other end is connectable to one electrode, and one end is connectable to the other end portion in the arrangement direction of the second conductive plate and the other end is connectable to the other electrode A welding gun with a transformer, comprising: a second conductor. 2. A first conductive member that connects a plurality of transformers arranged in a predetermined direction and terminal plates connected to the secondary coils of the transformers in an integrated manner by pointing in the arrangement direction. A plate, a second conductive plate for integrally connecting the center tap terminal plates led out from the middle portion of the secondary coil in the array direction, and one end of the first conductive plate in the array direction of the first conductive plate. A first conductor which is connected to the intermediate part and whose other end is connectable to one of the electrodes; and a first conductor which connects one end to the middle part in the arrangement direction of the second conductive plate and the other end to the other electrode. A welding gun with a transformer, comprising: two conductors.