JPS5897667A - Method and device for detecting resistance and voltage between chips of resistance welder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Recently, in resistance bath welding, the resistance between chips has been increased.
l+:Using pressure as a monitor of bathing results is
It is actively practiced.

After the meeting, a method and apparatus for detecting the inter-chip resistance L and the inter-chip resistance will be presented.

Conventionally, the inter-chip resistance and inter-chip voltage have been detected by directly connecting the upper and lower chips with lead clamps.

Does not require 1% additional equipment compared to conventional detection methods.

Although it is very easy to detect, there are various problems in practical use as described below.

The tip was connected to the tip since it is constantly in contact with the VT bath contact. The detection lead wire may be damaged or cut at one time.

A tip-equipped gun for bath wetting is made into a bath welding machine, is made by a human or a robot, is swung, and is cut into the predetermined pre-cut lead.

Since the chip is a consumable item and is replaced quite frequently,
Each time, you have to reconnect the lead wires.

In addition, the lead wire is wired along with the secondary conductor where the large bath current is placed.

Because it is susceptible to the effects of fermentation, sometimes false signals are detected, so certain measures have been taken.

However, the conventional detection method of connecting a lead wire to the tip is very cumbersome and impractical for welding operations.

In contrast, the present invention is completely different from the conventional method, and has developed a method that allows detection without connecting lead wires to the chip, and a device that is extremely superior in practical terms.

An example of the method and method of the present invention will be described below with reference to the drawings.

Fig. 1 shows an equivalent representation of a bath welding machine, including an AC power source that supplies power to the welding machine, a 21d thyristor stack, 3 a bath welding transformer, and a resistance loop included in the 4-piece secondary conductor. , inductance L included in the 4-digit secondary conductor,
5 is the inter-chip resistance 1 (, 1) when the object to be bathed is inserted between the tm chips.

In addition to the resistance at, there is an inductance bX5 between the chips.
It is also said that +/) is small compared to the resistance tV, so this inductance is ignored here.

In Figure 1, the power supplied to the secondary circuit from the 2g4 children A and B of the bath-connected transformer is
It is composed of active power and reactive power, and the active power is equal to the power consumed by the resistance of the secondary circuit, that is, the resistance of the secondary conductor and the grinding force between the two. This is because the inductance L only stores and releases power, and does not consume t/lli of power.

Therefore, if the electric current flowing through the secondary circuit tflL, that is, the fg connection, is I, and the active power is P, the following relational expression holds true.

P=(ru+rut)I"...formerly...Tl), and by dividing the active power P by the square value of the bath connection power and further subtracting the resistance Ki of the secondary conductor, The resistance ll'ttf can be found.

Furthermore, it is clear that the inter-chip voltage Vt can be obtained by multiplying the inter-chip resistance R, t obtained by Equation 31 by the bath contact voltage aIt shown in Equation (4).

Vt=FLtXI...---(4
) As described above, if the effective power P and the welding capacity I are known, the inter-chip resistance t can be calculated without connecting lead wires between the chips.
The rough chip-to-chip voltage Vt can be determined.

Here, the formula (4) is a general formula, and in practice, the temporal changes in inter-chip resistance and voltage during welding are considered ambiguous in monitoring the welding results.

Therefore, it is necessary to find the interchip resistance and Narita every n/2 cycles of the AC power supply. The method will be described next.

FIG. 2 shows the waveforms of the bath contact transformer secondary voltage v (liIl'R value) and the bath contact voltage fit (instantaneous value).

'r may be any period of n/2 cycles of the alternating power supply frequency, but for the purpose of simplifying the explanation here, n =
], which is half a cycle of the source frequency.

1+L and tl can be arbitrarily set as long as the bath contact current t is zero, but here, H-PI is assumed to be the time point at which the half-cycle electric current is applied.

The active power P during period 'r can be expressed by equation (5).

p = 7 Jtt, vLd t・”...”・LD
) Similarly, the square of the bath-contact lightning in the period r is 1tj
(It can be expressed by equation 61.

”=T J”t,” ””・・・・・・・・・(6)1
5), (6) expression! Substituting - into 92, we get the resistance ratio t between the electrodes and the formula (7).

If the total JIE of equation (7) is performed during the bath contact period, the interchip resistance 1 (tl) can be determined for every half cycle.

Interchip resistance L per half cycle (If it is 1, then (4
), the bath contact voltage fiI for every half cycle is L! - Multiplying by t, the chip-to-chip voltage Vt for each half cycle can be found.

If the peak value, average value, or effective value is determined as Vt, the peak value, average value, or effective value for each half cycle may be used as the power connection.

If the period 'r is chosen to be a half cycle as described in 1 above, the inter-chip resistance and voltage can be found for each half cycle, but the period 'r'
It is clear that if r is chosen to be n/2 cycles, the inter-chip resistance voltage for every n/2 cycles can be found in the same way.

In addition, the voltage V in equation (7) is here used as the secondary measurement path Fft of the transformer, but it can also be calculated using the -yaton field.

This is because -vcfs and the voltage on the secondary side are similar.

However, in this case, instead of using -am voltage itself, a voltage that is made smaller to match the voltage on the secondary side is used.

Further, the voltage 8Ev in equation (7) may be the voltage of the power supply.

However, as with the case of using the thicker voltage, the ratio value is used by reducing it to match the vc% secondary voltage. In this case @2
The voltage vri in the figure becomes a continuous sine wave, but since VL becomes zero during the period when the current t is zero (as a result of calculation of the force formula,
[It will be the same as when using second-order mFl.

In addition, I used the K151 formula to find the effective power (
5) You may find = using a method other than the formula.

Next, 51 methods of the present invention! An embodiment of the second application device will be described with reference to FIG.

FIG. 3 is a block diagram of a μ-chip resistance detection device 8 and a circuit for roughly calculating the bath contact voltage thereto; a four-pronged multiplier 15t; and a sized electrode chip interposition pressure extraction device;

The secondary side pressure V of the bath-connected transformer 3 and the bath-connected power supply? A certain means detects the trowel, inputs it to the effective force calculation circuit 9, and calculates the numerator P of the first term on the right side of equation (3). In addition, the bath ground voltage (HL is the bath ground ionization double nest value calculation circuit) OvC input fl,, (
Determine the denominator I2 of the first term on the right side of Equation 31.

Thus obtained 7tP and I'' are inputted to a -1 divider INvc to obtain the term p7x''-2 on the right side of equation (3). This P/jj and the signal from general setting @12 are input to the subtracter 13, and the inter-chip resistance Rt shown in equation 31 is obtained.

Next, vclF, find the voltage Vt between the four chips.
Either of the effective values is input to the welding ionization calculation circuit 14, and the resulting fcf# contact fiI and the inter-tip low portion t determined above are input to the multiplier 15. And (4
) Obtain the chip-to-chip voltage vtt shown in the equation.

Here I will explain the settings in a little more detail.

The setting 'a' is for outputting a signal corresponding to the secondary conductor resistance shown in equation (5). The secondary conductor resistance changes due to the consumption VC of the secondary conductor, but the speed of change is very slow, on the order of a day or a week, and only occurs once in a very short period of ten or more cycles. The bath exposure time can be considered constant. When using f, inter-electrode tip resistance Rt and voltage VBj as monitoring quantities, their true values are not necessarily required; it is sufficient to know the behavior of Rt and Vt that occurs during welding.

Therefore, the output of the R setting device 12 may be a constant value corresponding to the secondary conductor resistance &.

JIIJ diagram,! Active power calculation circuit 9 shown in Fig. 3
It weighs 7 tons.

Reset signal generated! 22 and sampling signal constant main unit 23
It generates a signal every n/2 cycles in order to calculate the active power P and the squared value of 1 for every n/2 cycles, for example, when n=3 or half Active power per cycle P and smta squared value I"?
Calculate/)l! If the signal is 1, a signal is generated every half cycle.

These reset signals and sampling signals (7)
From the formula, the active power P during the same period t, ~t□ as b
It is necessary to determine the square value II of the electric power source II and divide it, and it must be common to both the active power calculation circuit and the square value circuit.

First, to calculate the active power Pf shown in formula (5),
Bath contact at and bath contact transformer secondary voltage vf multiplied by IIL unit 1
6 and find V(kc)vt? The integrator 17 and sample hold device 18 are modified to repeat integration and hold every n/2 cycles.

Calculate the bath contact a2 remainder value 11 shown in equation (6) 4
゜S/) VC inputs the input side 0 to the multiplier 19.

Find j'' and repeat this 4'' with the integrator 20 and the sample rule.

As described above, one embodiment of the present invention can be realized in a 71-code manner.
) I mentioned the case shown in Figure 3.
It is also possible to implement this in software using a combination controller.

As described above, according to the present invention, the voltage on the primary side of the bath-connected transformer and the voltage on the secondary side! @Connection AT can be used to detect the inter-chip resistance (pressure).In other words, it can be detected with the signal VcL from the place where the electrode nap is bitten, so it is different from the conventional method of connecting IJ-Filt to the electrode tip. Compared to other methods, this method is extremely effective in solving all the troublesome welding operations mentioned at the beginning.

[Brief explanation of drawings]

FIG. 1 is an equivalent representation of a resistance welding machine with a t-vapor symbol. This represents the waveform of the electrical connection hood. FIG. 3 is a block diagram of an equivalent circuit of a bath wetting machine and an embodiment of the present invention. @Figure 4 shows the active power calculation circuit 9 and bath connection fi2 in Figure 3.
It is a block diagram specifically showing a multiplication value calculation circuit 1i1110. [Brief explanation of the drawings] 1. Welding power source 2, Sirius dust ivy 3, Welding transformer 4, Welding machine secondary conductor resistance 5, ## Inductance 6, Inter-chip resistance 7, Current detector 8, Terra 1 resistance Block diagram of the detection device 9, active power calculation circuit 10, 1@connected a2 power calculation circuit] 1. Divider】2. R setting device 13, subtractor 14, ! i! Electrical equipment circuit 15"6, 19. Multiplier 17! O, integrator 1821, sample hold device 22, reset signal generator 23, sampling signal generator 澹・i -@ →111

Claims (4)

[Claims] (1) What is the voltage of the secondary rod 11 on the primary side of the transformer connected to the panel and the voltage of the secondary rod 11? Let us assume that the active power source supplied to the secondary circuit of the bath welding machine is n/2 cycles, and its effective power is defined as the square of the bath welding power lt. n/2 of AC power supply
A method of detecting the nano 1...Gi resistance by dividing the integral for each cycle and subtracting the grind resistance of the secondary conductor from the division 1. (2) The hair-resistant transformer is supplied to the secondary circuit of the bath water heater using the 1st, 11th, 2nd and 1st law tonden and common connection pipes.
) Valid deer? Calculate every n/2 cycles of the original,
What 5Ph energize all the above is also neutralized by the f direct which integrates the square of 1iif every n/2 cycles of the alternating power supply,
A method of subtracting the resistance value of the secondary conductor of the bath contactor from the division 1, and ejecting the voltage between the electrodes by adding the voltage p value for each 0/2 f cycle of the bath contact Km to the subtracted cough. . (3) Secondary to the primary 7IC of the bath contact transformer! +Q
What is the active power supplied to the secondary circuit of the unloading machine through the voltage and voltage of ? and an effective force calculation circuit that calculates the intersection every n/2 cycles of the critical source. A circuit for calculating the square value of the bath contact voltage every n/2 cycles of the total AC power supply; a divider for outputting a value corresponding to the resistance H of the bath contactor's permanent conductor; and a value setting device for subtracting the output of the value setting device from the output of the divider. Resistance detection between Nano 1 with VC#. (4) Using the Ikkyu 1 rule of the bath-connected transformer and the secondary ill's tonden and the 醊connection electric rabbit, we exchange the power that is supplied to the secondary 11 of the fg connection /J 礪源 n/! Intersect the active power calculation circuit that calculates each cycle with the square of the common ground voltage /i
Bath contact dl[+ calculated every 1/2 cycle of W power supply
5! Square III calculation circuit, a divider for dividing the active power by the square value of the bath welding machine, and a signal corresponding to the resistance FL of the secondary conductor of the welding machine. and a t-th subtracter that subtracts the output of the R setter from the output of the divider, and a bath tangent*a calculation circuit that calculates the vL value for each n/2 cycle of the ffj2 tangent current. , a multiplier for multiplying the output of the subtracter and the output of the bath connection voltage calculation circuit.