JPH0757421B2 - Output transformer with rectifier - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an output transformer with a rectifier used in a DC resistance welding apparatus or the like, and more particularly, to a center on a side surface outer peripheral portion of a container which is a member for a secondary coil. With a tap,
The present invention relates to an output transformer with a rectifier configured to mount a rectifier on both sides of the container.

[Background of the Invention] In order to downsize an output transformer, an output transformer has been proposed in which a toroidal core is used as a transformer core and a secondary coil also serves as a container.

An example of an output transformer in which this type of secondary coil also serves as a container is shown in FIG. The output transformer 2 shown in the figure is the Japanese Patent Publication Sho 52
The technique disclosed in Japanese Unexamined Patent Application Publication No. 208-208, in which the bottom conductor 8 is integrally attached to the output transformer 2 below the hollow square outer conductor 4 and is directed upward from the center thereof to serve as a terminal conductor. The rod-shaped inner conductor 10 which is also used is attached.
In this state, the toroidal core 14 equipped with the primary coil 12 is seated in the hollow portion of the outer conductor 4 so as to penetrate the inner conductor 10, and further, the inner conductor 10 penetrates above the outer conductor 4. Lid conductor having holes 16 of
Attach 18 In this case, a rod-shaped terminal conductor 20 is fixed to the lid conductor 18. Further, the cover conductor 18 is provided with two holes (not shown) so that a lead wire (not shown) of the primary coil 12 is led out of the container.

The electric circuit of the output transformer 2 configured in this way is the second
It is configured as shown in the figure. That is, toroidal core
The number of turns of the primary coil 12 wound around 14 is arbitrary X times, and the inner conductor 10, the bottom conductor 8, the outer conductor 4, and the lid conductor are wound.
Due to its structure, the number of turns of the secondary coil consisting of 18 is one, and it is said that the transformation is performed at a ratio of X: 1.

By the way, normally, a full-wave rectifier circuit is used as a rectifier circuit of a DC resistance welding device in terms of efficiency and ripple. In order to make a full-wave rectifier circuit in the electric circuit of the output transformer 2 shown in FIG. 2, as shown in FIG.
It is necessary to connect 2d in a bridge type to form a so-called single-phase full-wave bridge rectifier circuit. However, the single-phase full-wave bridge rectifier circuit has twice the number of rectifiers as compared with a single-phase full-wave center tap rectifier circuit described later, and eventually the structure of the rectifier circuit using such an output transformer 2 is large and large. There is a drawback that it becomes a complicated shape.

Further, according to the above-mentioned conventional technique, the material of the toroidal core 14 is a silicon steel plate or a ferrite iron core, which once converts direct current into high frequency alternating current, supplies the high frequency alternating current to the output transformer and steps down the voltage, and then the rectifier. Even if it is used in an inverter type DC resistance welding apparatus that is used again for direct current conversion, the core loss increases, so the cross-sectional area cannot be reduced, and there is the drawback that sufficient size and weight cannot be achieved.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned inconvenience, and a rectifier is integrally attached to both side portions of a hollow container which also serves as a secondary coil, and a center is provided on a side surface outer peripheral portion of the container. An object of the present invention is to provide an output transformer with a rectifier, which can reduce the number of rectifiers by forming a single-phase full-wave center tap rectifier circuit by providing tap terminals, and can also reduce the size and weight.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention provides an annular transformer core having a primary coil mounted in a columnar container having a hollow interior. In the output transformer in which is a conductor and also serves as a secondary coil, a rectifier attached with one pole side in contact with both side portions that are substantially the secondary coil of the container, and the other of the rectifiers An output terminal formed on the pole side of the container and a center tap terminal provided on the side surface outer peripheral portion of the container, and a welding current is supplied to the work by the output terminal and the center tap terminal. To do.

Further, according to the present invention, the first and second inner conductors which are electrically connected to the container also serving as the secondary coil after passing through the hollow portion of the annular transformer core having the primary coil mounted thereon are in parallel with each other. First and second conductors in which the first and second inner conductors are set to face each other in opposite directions, and first and second contacts one pole side of the first and second conductors. 2 rectifiers, and 3rd contacting the other pole side of the 1st and 2nd rectifiers
And a fourth conductor, an output terminal integrally formed with the third and fourth conductors, and a center tap terminal provided on the container. The output terminal and the center tap terminal are provided for the workpiece. It is characterized by supplying a welding current.

Further, according to the present invention, the first and second inner conductors that are electrically connected to the container also serving as the secondary coil after penetrating through the hollow portion of the annular transformer core having the primary coil mounted thereon are parallel to each other. First and second conductors in which the first and second inner conductors are provided in a value facing each other in opposite directions, and one pole side of a connecting portion extending from the first and second conductors First and second rectifiers attached in contact with each other; an output terminal formed on one of the gun arms and integrally abutting on the other pole side of the first and second rectifiers; And a center tap terminal provided to the one gun arm. The welding current is supplied from the output terminal to the one gun arm, and the welding current is supplied from the center tap terminal to the other gun arm.

[Embodiment] Next, an output transformer with a rectifier according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 4 shows a schematic configuration of a DC resistance welding apparatus that employs the rectifier-equipped output transformer according to the present invention. This DC resistance welding apparatus comprises a converter section 40, an inverter section 42, and an output transformer 44 with a rectifier according to the first embodiment of the present invention.

The DC resistance welding device is a rectifier stack in which the three-phase AC output from the commercial three-phase AC power supply 46 constitutes the converter section 40.
DC is converted by 48 and capacitor 50. This direct current is converted into a high-frequency alternating current, for example, an alternating current of 10 KHz by the full-bridge type inverter unit 42 including the transistors 52a to 52d and the like, compared with the frequency of the three-phase alternating current.

This high-frequency alternating current is introduced into the primary coil 58 through the primary coil lead wires 57a and 57b forming the output transformer 56 via the output terminals 54a and 54b. This primary coil 58 is wound around a transformer core 60 made of an amorphous material,
Secondary coil 62a, 62b terminals with center tap terminal 62
An output voltage is induced in 63a and 63b. This output voltage is converted into direct current by the rectifiers 64a and 64b forming a single-phase full-wave center tap rectifier circuit, and the welding electrode 66 that clamps the workpieces Wa and Wb.
It is configured to be supplied to a and 66b. The welding electrode
66a is connected to the common output terminal 68 of the rectifiers 64a, 64b, the welding electrode 66b is a secondary coil 62a constituting the output transformer 56,
It is connected to the center tap terminal 62 of 62b.

5 and 6 are views showing the structure of the output transformer 44 with a rectifier in the DC resistance welding apparatus shown in FIG. 4, FIG. 5 is a longitudinal sectional view, and FIG. 6 is an exploded perspective view. It is a figure.

The rectifier-equipped output transformer 44 includes flat plate-shaped first to fourth conductors 70, 72, 74 and 76 arranged in parallel with each other and the first to fourth conductors.
And a rectifier 64a interposed between the third conductors 70 and 74 and a rectifier 64b interposed between the second and fourth conductors 72 and 76.
A first inner conductor 78 valued on the first conductor 70, a second inner conductor 80 valued on the second conductor 72, and the first
And an annular, so-called toroidal-shaped transformer core 60 and its transformer core 60, through which the hollow portion is penetrated by the second inner conductors 78, 80 and the primary coil 58 is wound.
And first and second container conductors 82 and 84 that substantially surround the.

Both end surfaces of the transformer core 60 around which the primary coil 58 is wound are supported by one surface portion of the support plates 85a and 85b, which are conductors, via packing members 86a to 86h made of an insulator.
The transformer core 60 is externally fitted so as to be surrounded by the first and second container conductors 82 and 84, and holes are formed in the flange portions 87 and 88 that form the first and second container conductors 82 and 84. The transformer core 60 is positioned and fixed in the container composed of the support plates 85a and 85b and the first and second container conductors 82 and 84 by fastening the bolts 94 and the nuts 96 between the portions 90 and 92. .

The first and second container conductors 82 and 84 are cylindrical side surfaces, respectively.
As shown in FIG. 5, cooling water passages 102 and 104 are provided on the side surfaces 98 and 100, respectively. In this case, the passages 102 and 104 are provided with cooling water introduction ports 106 and 108 and discharge ports 110 and 112, respectively (see FIG. 6).

The side surface portions 98, 100 are provided with primary coil output ports 116a, 116b via cylindrical insulating members 114a, 114b, and lead wires 57a, 57b of the primary coil 58 wound around the transformer core 60 are provided. From the primary coil output ports 116a and 116b to the inverter unit 42
Are connected to the output terminals 54a and 54b.

The other surface portions of the support plates 85a and 85b are sandwiched by insulating plates 120 and 122 formed of two disk portions 118a and 118b. The first conductor 70 and the second conductor having the first inner conductor 78 and the second inner conductor 80 as connecting conductors so as to penetrate through the large-diameter holes 124 and 126 formed in the insulating plates 120 and 122. 72 and 72 are provided. The first inner conductor 78 has a hole 1 formed in the insulating plate 120.
While penetrating 24, it penetrates the hole 127a of the support plate 85a and the hollow part of the transformer core 60 in an insulated state and abuts on a circular recess 125 provided in the support plate 85b. The one conductor 70 and the support plate 85b are electrically connected.

On the other hand, the second inner conductor 80 has a hole 126 formed in the insulating plate 122.
Through the hole 127b of the support plate 85b and the hollow portion of the transformer core 60 in an insulated state, and abuts on the recess 136 formed in the support plate 85a. And the support plate 85a are electrically connected.

The cathode electrodes 138 and 140 of the rectifiers 64a and 64b are in contact with the outsides of the first and second conductors 70 and 72, and the anode electrodes 14 and
2, 144 are in contact with one surface portions of the third and fourth conductors 74, 76, respectively. The large diameter portions of the hollow conical disc springs 146, 148 are in contact with the other surface portions of the third and fourth conductors 74, 76, and the support plates 150, 152 are attached to the small diameter portions of the disc springs 146, 148. It is arranged. Holes 154 and 156 are formed in the peripheral portions of the support plates 150 and 152, and hole portions 162 and 164 are formed in the peripheral portions of the hole portions 154 and 156 and the third and fourth conductors 74 and 76. Penetrating insulation screw 16
6, 168 are inserted through the first and second container conductors 82, 84.
The main body of the output transformer 44 with a rectifier is assembled by being screwed into the screw holes 174 and 176 formed in the peripheral portions 170 and 172.

The third and fourth conductors 74, 76 are electrically connected to the tongue pieces 178, 180 provided on them through a plate member 182 which is a conductor having a U-shaped cross section. That is, one lateral surface portion 184 of the plate member 182 overlaps with the tongue piece portion 180, and these members are screwed with the bolt 186 and the nut 188. On the other hand, the plate member 18
The other side surface portion 190 of 2 is the first output conductor plate 192 and the tongue piece portion 1.
The common output terminal 68 is formed by being engaged with a bolt 194 and a nut 196 while being sandwiched by 78. This first output conductor plate 192
Is electrically connected to the welding electrode 66a as shown by the chain double-dashed line in FIG.

One end of the second output conductor plate 198 is superposed on the flange portions 87, 88 of the first and second container conductors 82, 84, and the bolt 200,
The center tap terminal 62 is formed by engaging the second output conductor plate 198 and the flange portions 87 and 88 with the nut 202. The other end of the second output conductor plate 198 is connected to the welding electrode 66b.

Insulating oil 206 is provided in the hollow portion 204 defined by the container composed of the first and second container conductors 82 and 84 and the support plates 85a and 85b.
And the cooling water introduction ports 106 and 108 and the discharge ports 110 and 112 are connected to pumps (not shown), respectively.

The output transformer with a rectifier according to the first embodiment is basically constructed as described above, and its operation and effect will be described below.

First, the primary side power switch (not shown) of the DC resistance welding apparatus shown in FIG. 4 is closed, and at the same time, the pump (not shown) is operated to introduce the cooling water introduction ports 106 and 108 and the passage 10.
Cooling water is allowed to flow between 2, 104 and the exhaust ports 110, 112.

In this state, the three-phase alternating current output from the three-phase alternating current power supply 46 shown in FIG. 4 is converted into direct current by the rectifier stack 48 and then introduced into the inverter section 42. in this case,
For example, a pulse width modulated drive pulse is introduced from the base drive circuit (not shown) to the bases of the full-bridge type transistors 52a to 52d that form the inverter section 42 and compared with the commercial frequency of the three-phase AC power supply 46. Then, a high frequency, for example, an alternating current of 10 KHz is input to the primary coil 58 side of the rectifier-equipped output transformer 44 via the output terminals 54a and 54b and the lead wires 57a and 57b. That is, as can be appreciated from FIG. 5 and FIG. 7 showing the schematic wiring,
The high frequency alternating current output from 42 is introduced into the primary coil 58 wound around the toroidal transformer core 60 a predetermined number of times. The high-frequency alternating current introduced into the primary coil 58 generates an interlinking magnetic flux φ that alternates so as to surround the rectangular cross section formed by the transformer core 60.

This interlinkage magnetic flux φ has the first and second inner conductors 78 and 80, the support plates 85a and 85b, and the first and second inner conductors 78 and 80 that form the secondary coils 62a and 62b whose center tap terminals 62 are the contact points of the flanges 87 and 88. A secondary voltage is induced in the second container conductors 82 and 84. Then, the induced voltage is transmitted to the first conductor 70 and the second conductor 72 through the first inner conductor 78 and the second inner conductor 80, respectively, in the secondary coil constituent member. The alternating current transmitted to the first and second conductors 70, 72 is single-phase full-wave rectified by the rectifiers 64a, 64b, and the rectified current is between the welding electrodes 66a, 66b holding the works Wa, Wb. It is supplied through the common output terminal 68 of the third and fourth conductors 74 and 76 and the center tap terminal 62. As a result, the contact portion between the works Wa and Wb is melted and the works Wa and Wb are joined.

In this case, according to the first embodiment, iron loss generated in the primary coil 58, the transformer core 60, the rectifiers 64a and 64b, the secondary coil constituent members such as the first and second inner conductors 78 and 80, and the like. Heat such as copper loss, that is, heat generated in the container is insulating oil.
206, via the first and second container conductors 82, 84
Also, heat is effectively exchanged with the cooling water flowing through the flow passages 102, 104 provided in the side surfaces 98, 100 of the second container conductors 82, 84, so that the heat radiating action is performed. As a result, the output transformer 44 with a rectifier can be downsized. In particular, since the transformer core 60, which uses an amorphous material with a small iron loss at high frequencies, which contributes to downsizing of the transformer and higher frequencies, has deteriorated characteristics at high temperatures, the cooling structure is extremely suitable.

Next, an output transformer 300 with a rectifier according to a second embodiment of the present invention will be described below with reference to FIGS. 8 to 10. The same components as those of the rectifier output transformer 44 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In this case, the output transformer 30 with a rectifier according to the second embodiment
0 is configured to directly sandwich the rectifiers 64a and 64b between the first and second conductors 302 and 304 and the output terminal 306.

The first and second conductors 302 and 304 have disc portions 308a and 308b and connecting portions 310a and 310b, and the disc portions 308a and 308b have the first and second inner conductors 78 and 80 as connecting conductors, respectively. Is installed (see FIG. 9). The first and second conductors 302, 304 include
Introduction passages 312a, 312b communicating with the introduction ports 106, 108 of the first and second container conductors 82, 84 and the discharge ports 110, 112.
In addition, discharge passages 314a and 314b are formed. The respective introduction passages 312a, 312b and the discharge passages 314a, 314b are connected to each other by the connecting portion 310a,
At 310b, it opens to the outside and is connected to a pump (not shown).

The output terminal 306 is provided substantially on one end side of the fixed gun arm 316, and the anode electrodes 142, 144 of the rectifiers 64a, 64b directly contact with both side surfaces of the output terminal 306, and the rectifiers 64a, 6
The cathode electrodes 138, 140 of 4b are connected to the first and second conductors 302, 3
It engages with the connecting portions 310a and 310b of 04. At that time, output terminal 30
Insulating plates 318a and 318b are arranged between the connecting plate 6 and the connecting portions 310a and 310b, and the rectifier 64 is installed in the insulating plates 318a and 318b.
Openings 320a and 320b for inserting a and 64b are formed.

While the welding electrode 66a is attached to the fixed gun arm 316, the welding electrode 6a is attached to the movable gun arm 322 shown by the chain double-dashed line in FIG.
6b is attached.

In the output transformer 300 with a rectifier configured in this way,
Movable gun arm under the action of an actuator (not shown)
322 is displaced to the welding electrode 66a side, and the first and second workpieces Wa and Wb are sandwiched by the welding electrode 66a and the welding electrode 66b.
Similarly to the rectifier-equipped output transformer 44 according to the embodiment, the rectified current is supplied between the welding electrodes 66a and 66b to perform the work of joining the works Wa and Wb.

In this case, in the rectifier-equipped output transformer 300, since the disk portions 308a and 308b forming the first and second conductors 302 and 304 are exposed to the outside over a relatively large area, the disk portions 308a and 308b are effective. Cooled, transformer core 60
The effect of improving the cooling efficiency can be obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, the center tap is provided in the container that also serves as the secondary coil, and the rectifier is integrally fixed to form the rectifier-equipped output transformer. Therefore, the number of rectifiers can be halved compared to the single-phase full-wave bridge rectifier circuit. Moreover, by using an amorphous material for the transformer core and increasing the frequency, while filling the container with insulating hot water to improve heat exchange with the outside of the container, the transformer core and the output transformer itself with a rectifier are efficient. Can be effectively cooled, and the output transformer with a rectifier can be downsized. Furthermore, the cooling effect can be further enhanced by flowing the cooling water through the container, and the size can be further reduced.

[Brief description of drawings]

1 to 3 are explanatory views of an output transformer according to a conventional technique, FIG. 4 is an electric circuit diagram of a DC resistance welding apparatus incorporating an output transformer with a rectifier according to a first embodiment of the present invention, and FIG. Is a longitudinal sectional view of the output transformer with a rectifier, FIG. 6 is an exploded perspective view of the output transformer with a rectifier, FIG. 7 is a schematic view of the output transformer with a rectifier shown in FIGS. 4, 5, and 6. FIG. 8 is an electric circuit diagram, FIG. 8 is an exploded perspective view of an output transformer with a rectifier according to a second embodiment of the present invention, FIG. 9 is a sectional view of the output transformer with a rectifier shown in FIG. 8, and FIG. FIG. 10 is a schematic electric circuit diagram of the rectifier-equipped output transformer shown in FIGS. 40 …… converter part, 42 …… inverter part 44 …… rectifier output transformer 56 …… output transformer, 58 …… primary coil 60 …… transformer core 62 …… center tap terminals 62a, 62b …… secondary coil, 64a, 64b ... Rectifier 66a, 66b ... Welding electrode, 68 ... Common output terminals 70, 72, 74, 76 ... Conductor, 78, 80 ... Inner conductor 82, 84 ... Container conductor, 102, 104 ... … Flow path 206 …… Insulating oil 300 …… Output transformer with rectifier 302, 304 …… Conductor, 306 …… Output terminals Wa, Wb …… Work

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiro Murakawa 1-10-1 Shin-Sayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (56) References: Special Table Sho 61-502385 (JP, A)

Claims (3)

[Claims] 1. An output transformer in which an annular transformer core having a primary coil mounted therein is disposed in a cylindrical container having a hollow interior, and the container is a conductor and also serves as a secondary coil. A rectifier that is attached in a state in which one pole side is in contact with both side portions that are secondary coils of the container, an output terminal formed on the other pole side of the rectifier, and a side surface outer periphery of the container An output transformer with a rectifier, comprising: a center tap terminal provided in a section, and a welding current is supplied to a work by the output terminal and the center tap terminal. 2. A first inner conductor and a second inner conductor which are electrically connected to a container that also serves as a secondary coil after passing through a hollow portion of an annular transformer core having a primary coil mounted thereon, and are in parallel with each other. First and second conductors in which the first and second inner conductors are set to face each other in opposite directions, and first and second contacts one pole side of the first and second conductors. 2 rectifiers, and 3rd contacting the other pole side of the 1st and 2nd rectifiers
And a fourth conductor, an output terminal integrally formed with the third and fourth conductors, and a center tap terminal provided on the container. The output terminal and the center tap terminal are provided for the workpiece. An output transformer with a rectifier characterized by supplying welding current. 3. A first and a second inner conductors, which are electrically connected to a container that also serves as a secondary coil after passing through a hollow portion of an annular transformer core having a primary coil mounted thereon, and are in parallel with each other. The first and second conductors in which the first and second inner conductors are provided in the opposite directions to the surfaces facing each other, and one pole side of the connecting portion extending from the first and second conductors. First and second rectifiers attached in contact with each other; an output terminal formed on one of the gun arms and integrally abutting on the other pole side of the first and second rectifiers; A center tap terminal provided, wherein a welding current is supplied from the output terminal to the one gun arm and a welding current is supplied from the center tap terminal to the other gun arm. Nsu.