JPS5924586A - Construction of transformer for resistance welding machine - Google Patents

Abstract

PURPOSE:To reduce size and weight by interposing a gate-turn-off thyristor between plural primary coils disposed in accordance with the secondary coil of a transformer for resistance welding so that said primary coils can change alternately polarities. CONSTITUTION:A pair of primary coils 1a, 1b are provided in accordance with a secondary coil 3. The one coil 1a is connected through the one side thereof to a primary terminal T1 and the other side is connected through M and N to the other terminal T2. The one coil 1b is connected at the one side thereof to the terminal T1 through O and P interposed between the same, and the other side is connected through Q and N to the other terminal T2. A gate turn-off thyristor 4 is further arranged between the terminals T1 and L and between the terminals T2 and P so that the coils 1a, 1b change alternately polarities and generate high frequencies.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a transformer for a resistance welding machine, and an object of the present invention is to make the shape of the transformer smaller and lighter.

Regarding attempts to miniaturize this Ni transformer, see 4.
Various proposals have been made.

For example, it can be determined from the iron core 11y of the transformer [surface S is the equation % of the induced voltage].

Therefore, to reduce the cross section of the transformer.

■How to increase the number of turns (N) of the coil ■Magnetic flux density (B
) method of increasing 0 frequency (f) The above three methods have been proposed as representative methods. Let's consider these methods one by one.

In the first method above, that is, when increasing the number of turns (N) of the coil, the ratio of turns of the coil must always be constant between the primary and secondary sides, so the number of turns of the secondary coil and the primary coil should be changed. Just make them both equally large. However, in the case of transformers for resistance welding machines, increasing the number of turns in the secondary coil increases the internal impedance (Zt), which is undesirable, and the reality is that one or two turns are generally set at 4411 degrees. be.

Next, in the second method, that is, when increasing the magnetic flux density CB), it is possible to reduce the core cross section (8) to some extent, but if the magnetic flux density is increased too much, the excitation current will increase. , and the increase in iron JIJ becomes significantly large, so that there is a limit to the increase in magnetic flux density for practical use.

Furthermore, regarding the third method, that is, the method of increasing the frequency (f), the commercial current in Japan is 60 I
f7. If there is a region of 50) IZ and a region of 50)
Z The iron core 1Ili surface is 60 in the ratio of 1] hill
Hz can be made smaller. Therefore, rather than increasing this frequency (f) by some method, the present inventors focused on this third method, that is, a method of decreasing the core cross section by increasing the frequency (f),
As a result of our efforts to realize this, we have failed to produce this groundbreaking result. Specifically, we have developed multiple primary (till) coils that correspond to the secondary 111j coils, at least one pair or more. A gate turn-off zyristor is interposed between the pair of coils, and the coils of the pair are arranged so that they can alternately change the 4-ji characteristic, or if necessary, the pair on the next side is It is characterized by having a rectifier interposed between the round secondary coils (i11 coils).

The specific contents of the present invention will be explained below based on the embodiments shown in the figures, and FIG. 1 shows a block diagram of the electrical configuration of a transformer for a resistance welding machine according to the present invention.
(la) and (Ib) indicate a plurality of primary coils corresponding to the secondary coil (3), and a pair of paddles are arranged.

In addition, (4) shows the gate turn-off thyristor interposed between the coils la and lb in the above-mentioned example, and to explain the connection state, one coil la of the pair has one side connected through L. to the primary side terminal TI, and the other side to the fLlL terminal T via M and N.
I have contacted both.

The other fill 1b has one side connected to the terminal T.
1 through 0°P, and connect the other side with Q.
, N to the other terminal T2.

Furthermore, gate turn-off thyristor 4. are arranged between the terminals T1 and L, and between the terminals T1 and P, respectively, as shown, and the coils 1 of the above pair are arranged as shown in the figure.
The structure is such that a*1b can alternately change polarity to generate a high frequency.

However, to explain this polarity conversion in detail while also corresponding to Fig. 2, if one terminal T1 of the primary film is set to ■ and the other terminal T2 is set to ○, then
111 from +1+1, the flow is 2V; the flow is as follows: a +L 41 a -M-4N →T 2 of Zu Suiristar (::it Z diagram a).

The subsequent flow of current is shown below. T1→0→b-+I'→1 b→Q-◆N→T2(
Figure 21b).

T1 →0→L→1 ;ki→M→N-+1'2 (second
D≧Ucn.

T1→0-d-P→1b-4Q→N→T2 (Fig. 2 d)
.

If the polarity is reversed and the T2 side becomes ■, it is T-+NiM.
→1a-L-e-+T1 (21st Xle).

'11'-+N-4Q→1b→1)→f-+O→T, (
Figure 2 f).

A-+N→M-+ l a-4:ll, -+g −+
'l' 1 (Fig. 2g).

As a result of the above order, a current flows through the pair of coils la and lb in the direction of the arrow (in the direction of the dashed line arrow when the polarity changes), so that the pair of coils act to alternately change the polarity (see Figure 2). reference).

The secondary voltage required by the welding transformer is determined by the impedance (Z) of the secondary circuit and the required melting F & TIY flow (
T2], which is determined by the bond with E
= L2 XZ.

In other words, is it necessary to flow the same current? Secondary voltage (E)
The lower the impedance (Z), the smaller the impedance (Z), and as a result of this, naturally the KVA (voltage x current) also becomes smaller.

This impedance (Z) is the vectorial addition of the resistance valve <X<, ) and the actance (X), and is determined by Z=y'H'i, )Hz.

However, reactance (X) is expressed as become.

Therefore, in such a case, a rectifier 5. is installed on the secondary side of the transformer as shown in FIG. It is even more effective to reduce the impedance on the secondary circuit side by reducing the intervening frequency to zero.

That is, to explain the above in detail with reference to another embodiment shown in FIG. 3, a gate turn-off resetter (4) which is used to apply high frequency to the primary coil as in the above embodiment is used. and one layer of the pair of layers 01
Secondary coil 3a corresponding to 0 coils la and lb.

3b and! Rectifier 5 between 1111 children T36 and T4 respectively
．． This makes it possible to convert the secondary circuit into a direct current, and as a result, it becomes possible to reduce the actance (X) to 0 due to the increase in the 1th frequency.

The present invention is made clear by the following description: ii+! vinegar,
Since a high-frequency generator that also serves as a switch is provided on the primary side of the transformer, the cross section of the core can be reduced, and the transformer can be made smaller and more compact.

In addition, if a 61U regulator is interposed in the secondary circuit in addition to the above-mentioned primary side high frequency generator inside the transformer, the increase or actance caused by the secondary side high frequency generator can be drastically reduced. In addition to reducing the size and weight of the transformer due to the reduction in the core cross section mentioned above, it is also possible to reduce the interference in the secondary circuit, which is more preferable. However, if the cooling water of the welding transformer is connected to the above-mentioned high-frequency generator i3. It is possible to abbreviate the FM version of Isuiriku's cold J" 1 system, which is used for this purpose.

[Brief explanation of drawings]

Figure 1 shows a transformer for a welding machine which is an embodiment of the present invention.
The figure shows a high frequency generator itl. ? FIG. 3 is a graph showing the reversal of the f+'lj characteristic due to 1{], gas +k in a transformer for a welding machine, which is another embodiment of the present invention.
It is a block diagram of h. la. lb...Primary coil 3, 3a. 3b- - -Secondary {111 Koinore 4...
...High frequency generator 5..., 1 rectifier-4'l

Claims (3)

[Claims] (1) A gate turn-off risk is interposed between the primary coils and the secondary coils so that the polarity of the plurality of primary coils assigned to correspond to the secondary coils of the resistance welding transformer can be changed alternately. Characteristic transformer structure for resistance welding machines. (2) In order to enable the plurality of primary coils arranged corresponding to the secondary coils of the resistance welding transformer to alternately change the polarity, a gate turn/mets/silisk is interposed between the above-mentioned primary coils and the primary coils. . A transformer for a resistance welding machine t'? is characterized in that a rectifier is interposed between the secondary coils to bring the frequency close to zero. ¥ made. (3) In the device described in claims (1) and (2), the gate turn-off risk interposed between the primary and secondary coils is integrally built into the transformer. However, resistance welding 1:g: Machine transformer structure.