JPS61502385A - resistance welding machine - 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] resistance welding machine Background of the invention The present invention relates to resistance welding. Specifically, the present invention provides automatic pressure welding using a robotic welding machine. This article relates to improvements in resistance welding machines suitable for welding.

Resistance welding is a well-known method of joining two conductors. This method The current is flowed in an amount sufficient to locally heat the conductor and melt it. This is usually a pair Two conductors connecting the electrodes are placed facing each other, and pressure and voltage are applied between the electrodes. The heating time that occurs in I2R is adjusted so that the parts are sufficiently melted but not too melted. make a clause This method can be used with DC or AC! This can be achieved using either pressure. However, the connection Considering the contact resistance value of the two conductors being matched, it is possible to reduce the voltage from the normal power supply voltage. A transformer is used to step down the voltage to several volts or tens of ports, increasing the current from several thousand amperes to tens of thousands of volts. Preferably, the value is in amperes. The simplest resistance welding machine is a step-down transformer, the step-down A switch that controls the voltage supply to the transformer, and an electrical connection to the secondary winding of the step-down transformer. It consists of a pair of electrodes connected to. Apply electricity to sandwich the parts to be joined. Once the poles are in place, voltage is applied to the conductor junctions by closing the switch. The resulting electrical heat melts the point of contact with the electrode, welding the conductors together. .

When considering actual welding operations, various improvements have been made to the above-mentioned process.

In order to minimize the cost of the welding current supply transformer, it is desirable to connect the power source to the transformer. The peak value of the supplied voltage is determined by the saturation value of the transformer core or the curve of the B-H curve of the core. The goal is to make sure that it reaches the bottom part. For this purpose, the condition of the transformer core is You should always know this when applying voltage to

Hypothetically, the last voltage applied to the transformer magnetizes the transformer in a certain direction. , then if the applied voltage causes a current to flow in the same direction, the magnetizing current required in the transformer is added to the load current, causing an overload current to flow through the pressurizer during the first cycle. Ru. This is an undesirable situation, and so far we have prevented it by doing the following: In other words, the control circuit of a welding transformer always After completing welding, when welding starts, control the input voltage waveform so that it always points in the same direction. There is. This ensures that the first cycle of the supply voltage always has hysteresis in the transformer core. Closes the curve, prevents oversaturation current, and maintains a constant peak voltage value during each welding cycle. We guarantee it. Therefore, all that remains is to input the welding voltage to complete the welding. The only method is to supply a predetermined number of cycles of voltage. This Araka The specified number of cycles is determined empirically and is usually very small. This is a small value and should be controlled electrically, because the required supply time is This is because it is too short to be operated reliably by an operator.

The above resistance welding equipment is a major drawback when it is used for resistance welding within the production line. It has points. When welding two sheets of steel, they must be galvanized. Usually around 10,000 to 30, [100 amps] current is required. A transformer wound to supply such current to the secondary circuit The vessels typically weigh between 200 and 600 pounds and are cooled with water or external cooling equipment. It is necessary to The wire that carries the above current is actually quite large. these The equipment that deals with this problem on production lines in the automobile industry or other industries is Route the suspended insulated conductor from the upper retainer to the welded part with the water-cooled electrode, and start operation. The worker places the electrode at the point to be welded and applies external force to hold the electrode during the welding process. There is. Is this the device above? How many knots are used in automatic welding machines? have some kind of disability. Robots generally have a weight limit, so it is important to reduce the weight. This improves operability.

For automatic welding machines, the minimum spacing between adjacent welding points is limited by the size of the transformer. be done. Robotic welders are designed to draw thousands of amperes of current. Its operability is greatly hindered by being connected to a thick power cable. However, as the robot moves, the lifespan of thick cables like the one above is shortened. .

It is an object of the present invention to provide an electrical circuit for a resistance welding machine with reduced weight near the weld. be.

Yet another object of the invention is to provide an electric resistance welding machine suitable for use in robotic welding equipment. It is to provide an air circuit.

Still another object of the present invention is to provide a small and lightweight transformer. Due to its small size and light weight, it can be installed near the welding work area. A secondary conductor can be used and the secondary conductor can be shortened.

Yet another object of the invention is to provide an electric resistance welding machine suitable for use in automatic welding equipment. It is to provide an air circuit.

Other purposes include connecting to an AC power supply and It has a rectifier that rectifies the voltage and generates a rectified voltage that has both DC and AC components. Direct current resistance welding method and device. The rectified voltage is supplied to the inverter and The generator generates a square wave with a frequency higher than that of the AC power source. This square wave is medium It is fed into a step-down transformer having a secondary winding with a center tap. This secondary winding is is connected to the welding contact through a wave rectifier, which conducts the welding current through the component. conduction. If a frequency higher than the power supply frequency is used as the inverter output, the input It is possible to use step-down transformers, which are lighter than transformers operating at AC voltage frequencies of It becomes possible.

Brief description of the drawing Figure 1 is a block diagram of a circuit that implements the present invention. Figure 2 is a block diagram of a circuit that implements the present invention. More detailed block diagram FIG. 6 is a circuit diagram showing in detail the operation of inverter devices 44 and 46 in FIG. 2.

FIG. 4 is a detailed circuit diagram of the timer 48 in FIG. 2. FIG. 5 is a detailed circuit diagram of the drive circuit 52 in FIG. Circuit diagram Figure 6 is a cutaway perspective view of a step-down transformer manufactured and used to realize the present invention. , FIG. 7 shows the time chart of the voltage waveform in the circuit of FIG. 4. FIG. 1 shows the time chart for realizing the present invention. It is a block diagram of a circuit.

The AC voltage power supply 10 of FIG. 1 is connected to a rectifier 12. Here there are 3 connections This is typical when the power supply 10 is a six-phase AC power supply. death However, any number of sets of electrical energy can be used. The rectifier 12 has an alternating current as its output. It is connected to output a nearly direct current voltage containing components. The output of rectifier 12 is The power is supplied to a transformer 16 via a control circuit 14 which is a controlled inverter. system The control circuit 14 converts the output of the rectifier 12 into an alternating current voltage with a frequency higher than the input frequency. The effective value of the converted AC signal can be controlled.

A transformer 16 is shown in dotted lines and is connected to wire 1 as an input to step-down transformer 20. This is because it is useful for changing the voltages supplied to terminals 8 and 19. However, a certain clause Under the circumstances, it is preferable to connect the wires 18 and 19 directly to the control circuit 14. will be understood. This is a matter of design choice.

Step-down transformer 20 has a secondary winding with a center tap. Step-down transformer 20 The secondary conductors of are connected to rectifiers 22 and 24 to form a full wave rectifier. rectification The common connection of vessels 22 and 24 leads to a welding electrode 26. Step-down transformer 20 Center tap 28 is connected to welding electrode 30. Welding electrodes 26 and 30 are melted The control circuit 14 operates to supply current to the welding electrode 26 and the welding electrode 26. and 30 to effect resistance welding between the parts to be joined. control When the frequency of the output voltage of circuit 14 is higher than the frequency of power supply 100, step-down transformer 20 It can be made smaller and lighter than it would otherwise be. This is a stupid system that makes operation easier for operators. rather than allowing the transformer to be placed in the arm of the robot welder, thus can be moved freely over a wide range. In addition, smaller transformers can be made using automatic welding machines Fig. 2 shows a circuit for realizing the present invention. FIG. In FIG. 2, the rectifier 12 is connected to the power supply 10. and supplies voltage between bus bars 40 and 42. Inverter devices 44 and 46 are is connected between conductors 40 and 42, and their midpoint is connected to conductors 18 and 19 It is connected to the pressure vessel 20. In the circuit block diagram of Figure 2, the transformer shown in Figure 1 vessel 16 is excluded. As mentioned earlier, this is a design issue.

In the circuit of FIG. 2, rectifiers 22 and 24 are connected to the secondary winding of step-down transformer 20. The full-wave rectified output is passed through the welding electrodes 26 and 30 and a member (not shown) to the central It is generated so as to return to tap 28. The circuit shown in FIG. 2 is controlled by the timer 48. When activated, this timer determines the operating cycle of the inverter devices 44 and 46. and the relative time for adjusting the current intensity flowing through the welding electrodes 26 and 30. Ru. The current detection element 50 is connected to supply input to the timer 48 and is connected to the bus line. When the current in 40 exceeds a predetermined value, the inverter devices 44 and 4 Finish the operation in step 6.

The timer 48 outputs two outputs, which are input to the drive circuit 52. The dynamic circuit includes switching elements such as power transistors in the inverter devices 44 and 46. The upper part of the inverter device 44 is connected to drive the The conductor 18, the step-down transformer 200 primary winding, and the conductor 19 are connected to the inverter device. It is controlled so that it flows through the lower half of 46 to the bus bar 42. Second half cycle current passes through the upper half of the inverter device 46 and is connected to the first winding of the down-down transformer 200 via the conductor 19. flows in the opposite direction to the line. The current flows through the conductor 19 to the inverter device 44, and the inverter It flows through the lower half of the data device 44 to the bus bar 42. The details of this control can be found in more detail. This will become clear by examining the circuit diagram. Switch of inverter device 44 The elements that can be used are thyristors, SCRs, gate turn-off elements, etc. Ru.

FIG. 3 explains more detailed operation of the inverter devices 44 and 46 shown in FIG. FIG. In FIG. It is input to the rectifier 12 via a 0.6 limiting resistor 62 and three contacts 64.

The power supply 10 is usually 6-phase, 60 Hz, and has a voltage such as 480 volts nearby. be. The contact 64 is here energized by a contactor 63 controlled by a pushbutton 65. It is shown in This occurs when the press methane 65 is used before welding current is supplied or when welding is complete. to be operated as part of the opening/closing operation of welding electrodes 2G and 130 after completion. I'm assuming. Separately, the contactor 63 may be controlled by the timer 14 in FIG. is also possible.

As shown in Figure 6, the rectifiers 12 are connected to form a full wave rectifying bridge rectifier. A suitable number of diodes 66 are provided. Here six diodes - r6 6 is shown, but this number depends on the current being handled and the voltage applied to the diode. It will be obvious that the pressure and the number of phases different from 6 will vary. this These are design issues. The output of the rectifier 12 is a full-wave rectified voltage and is applied to the bus 42. Thus, the bus bar 40 becomes the positive electrode.

Inverter devices 44 and 46 are connected between busbars 40 and 42. Imba Since inverter devices 44 and 46 are identical, only inverter device 44 is shown.

In the inverter device 44, the power transistor 68 is connected to another power transistor 7. It is connected to the negative bus bar 42 through a series connection with 0. power transistor 68 is driven by Darlington Transistor Tough 2, and transistor 72 is a drive circuit. It is driven by 52. Darlington transistor as well as 70 power transistors This transistor is driven by the drive circuit 52. in The inverter device 46 includes power transistors 76 and 78, which also It is driven by a Linton transistor, but a Darlington transistor is used here. Not shown. The power transistor 68 is connected in series with the low voltage diode 80. This is bypassed by a resistor 82 and a capacitor 84. This suppresses a sudden rise in the voltage applied to the transistor 68. This is for power Depending on what transistor 68 is chosen, it may not be necessary. power transistors Data 70, 76 and 78 are similarly bypassed. Power transistor 68 and and γ0 are connected to one end of the primary winding of the step-down transformer 2a via the conductor 18. , and the common connection point 88 of power transistors 76 and 78 is connected to a down-conductor via conductor 19. It is connected to the other end of the primary winding of transformer 20.

A stabilizing capacitor 90 is connected entirely through the resistor 92 and between the positive electrode bus 40 and the negative electrode bus 42. It is connected to the.

The galvanometric element 50 has a current transformer 94, which connects the positive electrode bus 40 and the inside of the capacitor 90. Detect the flowing current.

This combination of connections ensures that the capacitance is To prevent a situation in which the electric current charged in the capacitor 90 causes accidental triangulation. current transformer 94 is connected to a galvanometer 96 and outputs a signal proportional to the measured current. this signal is input to a comparator 98 and compared with a predetermined voltage. Current value generates a signal that exceeds a predetermined reference value, this signal The signal is input to the timer 48 and controls the operation of the timer 48.

When the circuit shown in FIG. 3 is constructed and tested, the input voltage from power supply 10 is The timing circuit of the timer 48 shown in FIG. 2 is 1200Hz. It was operated to generate the input of a step-down transformer 20 operating at z. like this Under such conditions, the period-to-period voltage fluctuation between buses 40 and 42 can be ignored. However, the output of a normal full-wave 6-phase bridge rectifier has 3t5 [3Hz and It is known that it has an alternating current voltage component at its harmonic frequency. circuit operation It may be assumed that a DC voltage is applied between the bus bars 40 and 42. Exchange The current voltage is first multiplied by conducting power transistors 68 and 78. is supplied to step-down transformer 20, while power transistors 70 and 76 are non-conducting. It is. As a result, half a cycle of the AC voltage supplied to the step-down transformer 20 is generated. It will be done.

Next, the conditions are changed to make power transistors 76 and 70 conductive. resistors 68 and 78 are made non-conductive. This provides a reverse voltage to the step-down transformer 20. and supplies the other half period of the AC voltage of the step-down transformer. Step-down transformer 20 The voltage supplied to the primary winding is a 1200 Fiz square wave. Step-down transformer 20 The secondary winding of responds to a 1200 Hz square wave and generates a 1200 Hz approximately square wave, output to provide a full wave rectified signal with a small amount of Rizzoli to the welding electrodes 26 and 30; do.

FIG. 4 is a detailed circuit diagram of the timer 48 circuit shown in FIG. 2. In Figure 4, the simple Pulse generator 110 generates a rectangular monopulse having a width of 1.6 milliseconds. this The pulses are input to welding memory circuit 112. The pulse generator 114 is Outputs a variable width pulse at the specified frequency. These pulses are also applied to the welding memory circuit 1. There are 12 inputs. Weld timer circuit 116 generates a variable width rectangular pulse which is It is connected to the welding memory circuit 112 and enables welding for a predetermined time. . The welding memory circuit 112 also detects overcurrent from the current detection element 50 shown in FIGS. 2 and 6. It is overridden by a signal indicating current flow.

The output signal from weld storage circuit 112 is input to delayed ignition circuit 118. this is A flip-flop that delays the signal. the output of the delayed ignition circuit 118; The output of the pulse generator 114 and the output of the welding memory circuit 112 are NOR date 120. It is input to the Fritsuno 70tub 122 through . flip 70 tube 122 produces two outputs, which are square waves and signals of opposite sign. one of these is input to drive transistor 124 and the other to drive transistor 126.

The outputs of drive transistors 124 and 126 represent the output of timer 48, which The two power sources of the drive circuit shown in Figure 2 are supplied.

Considering the circuit of FIG. 4 in more detail, monopulse generator 110 is 128, which has a pair of NAND) f-) input states of 130 and 132. change. These are connected together to form a 7-lip flip, and the output The force is input to a monopulse generator 134. This is an anti-pakunsu circuit.

Switch 128 is shown here as a pushbutton, but this is not the case in the example circuit. This is because it was used in this form in . The initial trigger of the monopulse generator 110 is An electrical signal from another circuit or a microprocessor used in the welding control device. It is also possible to apply signals from these sources. This may be due to design choice or convenience of use. Ru.

The pulse generator 114 shown in FIG. 4 has a retriggerable and resettable monostable circuit. , which is designated as pulse generator 136 for simplicity. capacitor 138, resistors 140, 142, and variable resistors 146 and 148. The network is connected across resistor 150 to the positive power supply. Dio-r146 and The common connection point of 148 and 148 is connected to the pulse generator 136 and the diode 1 Either 46 or 148 is conductive depending on the sign of the voltage applied to its common connection point. It will be done. When diode 148 is conductive, the right half of resistor 142 and variable resistor 144 The sum of the resistance values for one pulse time is connected in series to a capacitor 138. It has established. When diode 146 conducts, it determines the period of the opposite half of the pulse. The resistance value is the sum of the resistor 140 and the rest of the variable resistor 144. sand In other words, if you change the setting of the variable resistor 144, only the relative length will change without changing the sum of the pulse widths. It can be changed. As a result, a constant frequency is output from the output terminal 152, in this case 120 A 0Hz rectangular wave is output, and the conduction period of each code can be set with a variable resistor 144. Wear.

Weld time timer 116 uses a single pulse generator 154. capacitor 15 6 is connected in series with a resistor 158, both of which are connected to a monopulse generator 154. It is. Resistance values of resistor 158, resistor 160, and variable resistor 162 The welding time is determined by the sum of and the value of the capacitor 156. Set variable resistor 162 By adjusting and setting the resistance value, the ON time length of the welding machine is adjusted. This feature is It is clear that it is possible to control the RC time in a single pulse generator by adjusting the resistance value logarithmically. Will. Separately, using a microprocessor, predetermined Control welding time according to fixed time and various other information such as measured values such as weld quality You can also do that. These are design issues and depend on what is expected of the circuit. change. In the illustrated welding time timer 116, the output from the output terminal 164 is A rectangular pulse whose pulse width is equal to the required welding time is typically seconds or minutes. This is about 1 second.

The signals from the single pulse generator 110, the pulse generator 114 and the welding time timer 116 All the numbers are input into the welding memory circuit 112. The output of the monopulse generator 110 is N OR/7”-) 166 single power, output of welding time timer 116 The signal from terminal 164 is provided as the other input to NOR date 166. . The output of NOR date 166 is added to the input of flip-flop 16B (DD terminal). This flip-flip is clocked by a signal from terminal 152. ing. If an overcurrent occurs, the Fritbu Fronno 168 will detect the current as shown in Figure 2. It is reset by a signal from output element 50.

The non-Q output of the flip 70 horn 168 is the reset signal for the monopulse generator 154. It is also provided as an input signal to the delayed ignition circuit 118, where a single pulse is emitted. The signal is input to the generator 170. The output of the single pulse generator 170 is NOR'y"-) Supplied as 120 single power units.

The other input to NOR date 120 is pulse generator 1 supplied from terminal 152. 14 output and a Q output of Flip Flora 7°168. NOR date 1 The output of 20 is connected to the input of 7'1220, where it is connected to inverter 172 or Each NAND date 174 and 176 is supplied as a one-man power supply. Inverter 1 The output of γ2 is the clock input of flip-flop 178. outputs signals that are inverted with each other, and these are respectively NAND r-to174. and 176 inputs. The result is two equal and oppositely signed rectangles. waves are generated and these serve as inputs to drive transistors 124 and 126. Ru. Again referring to the 6-man power of the NOR'r'-to 120, the delayed ignition circuit 11 The input from 8 sets the first pulse to the subsequent pulse in any weld section. Rusu Yoshi is also kept short. This results in a gradual change as shown in Figure 1 at the start of welding. This prevents the magnetic core of the pressure vessel from becoming saturated. NoRr from welding memory device 112 - The input signal to date 120 may output a rectangular pulse at the output of NOR date 120. Define the total time. This is the length determined for a single weld. terminal 15 The input from 2 to NOR date 120 is all the remaining rectangles except for the first pulse at each weld. Generates shaped pulses. These pulses have a fixed frequency and a variable resistance This signal is determined by the device 144.

FIG. 5 is a detailed circuit diagram of the drive circuit shown in FIG. 2.

In FIG. 5, timer 184 receives a signal from drive transistor 124 in FIG. Strengthen. A timer 186 with the same specifications receives an equivalent signal from the drive transistor 126. Strengthen. The circuits used as timers 184 and 186 are the same, so Only the machine 184 will be described in detail.

Timer 184 generates a pulse, which is fed to power amplifier 188 shown in FIG. is used to drive the inverting amplifier 190. From the drive transistor 124 The input pulses are also provided to a non-inverting amplifier 192. Inverting amplifier 190 and Both the non-inverting amplifier 192 and the primary winding 194 of the transformer 196 are connected to each other. A portion of the periodic current is provided by each of these amplifiers. Transformer 196 is the secondary winding 198 and a secondary winding 200. The secondary winding 198 also connects to the shaping circuit 202. Secondary winding 200 is connected to shaping circuit 204 .

The shaping circuit 202 is connected to the circuit shown in FIG. Tries continuity. The shaping circuit 204 is connected to the circuit shown in FIG. Transistor 78 is turned off. Corresponding shaping times of the same part shown in Figure 5 The circuits are similarly connected as shown, one connected to the power transistor shown in FIG. The other side is connected to the power transistor 70 shown in FIG. Connected to ensure continuity.

In the circuit shown in Figure 4, the inputs of timers 184 and 186 are shown reversed in a sense. There is. Therefore, the voltage at transformer 196 and the voltage at the symmetrical portion of the circuit shown in FIG. The pressures are in opposite phase. The outputs of the shaping circuits 202 and 204 are connected to the circuit shown in FIG. As a related consideration, when the pulse shaping circuits 202 and 204 generate current, the It will be seen that transistors 68 and 78 are brought into conduction. The descent shown in Figure 6 The conduction of the transformer 20 is from left to right. The converse is also true, and the input polarity in Figure 6 is When reversed, power transistors 70 and 76 become conductive and the current flows as shown in FIG. Flow from right to left of the step-down transformer. As a result of this operation, the step-down transformer 20 shown in FIG. A rectangular wave current having a frequency determined by a pulse generator 114 shown in FIG. 4 flows. No. The effective value of the current flowing through the step-down transformer 20 shown in FIG. 6 is determined by the variable resistor 14 shown in FIG. This can be determined by setting 4. These pulse numbers, which indicate the welding time, are determined by the variable resistor shown in Figure 4. Determined by resistor settings.

FIG. 6 is a cutaway perspective view of a step-down transformer 20 manufactured and used in an embodiment of the present invention.

In FIG. 6, a ferromagnetic core 210 includes a primary winding 212 and another primary winding 21. These windings are connected to each other. of the secondary winding 216 The beginning of winding is the terminal 218. The secondary winding 216 is a single water-cooled conductor; It is arranged to surround the winding 212 and the associated core 210. Secondary winding 2 16 continues to the center terminal 220, which is connected to the center terminal of the secondary winding 216. forming a group. In order to maintain the correct direction as the secondary winding, the secondary winding 2 16 then surrounds the primary winding 216 in the direction from corner 222 to corner 224 and opens the opening 22 6 to the terminal 228 to complete the secondary winding 216.

When resistance welding steel plates of a thickness commonly used by the Automobile Manufacturers Association, It requires a current of about 20,000 amperes from o, o o o o. In Figure 6 shows two rectifiers 22 and 24, and the transformer shown in Figure 6 realizes this circuit. There are four shown in the figure, and this number is required to flow the required current.

In Figure 6, diode 230 is used in parallel with diode P2S5 to carry the required amount of current. It's flowing. By connecting these two diodes in parallel, we get the diode shown in Figure 3. are made equal. Similarly, in FIG. 6, diode 234 is replaced by diode 236. The rectifier 24 is arranged in parallel with the rectifier 24 shown in FIG. die The common connection of odes 230, 232, 234 and 236 is not shown in FIG. However, it can be realized by inserting a conductor between the gap 238, which is currently separated. Ru. A plurality of inlets 240 and outlets 242 direct cooling water to grooves 244 in the secondary winding 216. It should not be flushed away.

The transformer shown in Figure 6 has been manufactured and tested for use in the circuit shown in Figure 6. be. In order to clarify the characteristics of the transformer rather than the method required to assemble it, is shown. One of these features is a central tap that can be used as a connection. This is a two-turn secondary winding. The rectifier semiconductor is connected to the water cooling terminal installed on the transformer. One of the features is that it can be installed and tightened tightly to the common terminal. It is. However, one of the outstanding features of the present invention is that the frequency is supplied to the primary side of the transformer shown in Figure 6, and by this, The iron content used in the iron core 210 can be lower than the value required when the frequency is low. . If the amount of iron is reduced, the amount of copper required will also be reduced, and the weight of the transformer shown in Figure 6 will be reduced. It is possible to reduce the Easier to place.

FIG. 7 is a time chart of voltage waveforms in the circuit shown in FIG. 4. Each waveform is Add the element numbers in Figure 4 to appropriate locations on the horizontal axis to distinguish them, and plot these waveforms. ij, -F: Indicates each output signal. In Figure 7, marked “114” The generated waveform is a rectangular wave generated by the self-excited oscillator 114. This waveform is marked T1. It rises at the time when it is started and is repeated at 417 microseconds. This square wave falls The point in time is indicated as variable by the arrow, and this time is determined by the variable resistor shown in Figure 4. The device 144 can be adjusted and set. The second waveform in Figure 7 is 110″. The output of the single pulse generator 110 as marked, a rectangle with a pulse width of 1.6 milliJ seconds. It's a wave.

The rectangular pulse is at time T in FIG. This time is indicated to start at This is determined by the operation switch 128 shown in Figure 4, and as mentioned earlier. Other signals or! It can be similarly determined using a program.

After time To, T] is the point at which the square wave of the pulse generator 114 first rises. It is determined. At this point set the rectangular pulse marked 112”, this is the welding record. This is the output of the storage circuit 112. This is a rectangular single pulse that starts at time T1 and This period lasts until the end of the connection, and lasts from a few seconds to a few seconds. It's time T. It is also the starting point of the waveform marked 118'. This starts at time T□ 208 It is a rectangular monopulse that ends after milliJ seconds. This signal is the output of delayed ignition circuit 118. The width of the first pulse after welding is started is shorter than the width of the remaining pulses.

In the waveform shown in FIG. 7, the signal marked 120" The output is 0. This corresponds to the waveforms "112", "114" and "118" in Figure 7. It is the negation of logical units. Time T2 is a square wave representing the output of the pulse generator 114. The falling edge is indicated as time T3, while time T3 is the output of the delayed ignition circuit 118. It is defined as the point at which the waveform falls. As shown in the diagram, time T2 is If it occurs before time T3, the waveform marked 120" will start at time 3 and thereafter. This is the inverted version of the waveform "114". If time T2 is selected after T3 If so, the waveform "120" is the inverse of the waveform "114". Waveform ″120 '' is the source of the waveforms marked ``174'' and ``176''. These 1 The waveforms marked ``74'' and ``176'' respectively correspond to the NAND data shown in FIG. outputs of ports 174 and 176. As is clear from the figure, the waveform “174” is It is a combination of every other pulse of waveform ``'120'', and waveform ``176''. ” consists of the remaining pulses of waveform “120”. These are the inverter device 44 and 46 alternately to generate the number of rectangles as required.

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Claims (9)

[Claims] 1. A method of resistance welding a conductive member, comprising: a. Rectified voltage from AC voltage at commercial frequency a rectification process for generating; b. A switch for making the rectified voltage an AC voltage with an operating frequency higher than the commercial frequency. conversion process; c. Transformation process to lower the AC voltage at the operating frequency to obtain a step-down voltage ; d. Resistance welding consists of the step of supplying the step-down voltage to the member through the welding contact. Tangential method. 2. In the method according to claim 1, further: a. a rectification process for generating a DC voltage from an AC voltage at an operating frequency; b. A resistance welding method comprising the step of supplying the DC voltage to the member through a welding contact. . 3. A resistance welding device for electrically conductive members, comprising: a. Rectified current from AC voltage at commercial frequency a rectifier for generating pressure; b. An instrument for converting the rectified voltage into an AC voltage with an operating frequency higher than the commercial frequency. an inverter device; c. Transformer to lower the AC voltage at the operating frequency to obtain a step-down voltage With vessel; d. and a device for supplying the stepped down voltage to the member through the welding contact. Resistance welding equipment. 4. The apparatus according to claim 3 further comprising: a. Operating frequency AC voltage a rectifier for generating DC voltage from; b. and a device for supplying the DC voltage to the component through the welding contact. connection device. 5. A resistance welding machine connected between a commercial frequency AC power source and a pair of welding electrodes An electrical circuit comprising; a. connected to the AC power supply and for generating rectified voltage. With a rectifier; b. The rectifier is connected to the rectifier so that the rectified voltage of the rectifier is higher than the frequency of the AC power source. an apparatus for converting at an operating frequency and generating an alternating current voltage at the operating frequency; c. A step-down transformer connected to the rectified voltage converter has a pair of secondary terminals connected to the rectified voltage converter. a voltage converter that outputs a voltage lower than the voltage output from the rectifying voltage converter at the operating frequency; a step-down transformer, and each secondary terminal of the step-down transformer is connected to the welding electrode pair. An electrical circuit of a resistance welding machine, characterized in that it is connected to one of each. 6. A resistance welding machine connected between a commercial frequency AC power source and a pair of welding electrodes An electrical circuit comprising; a. connected to the AC power supply and for generating rectified voltage. With a rectifier; b. The rectifier is connected to the rectifier so that the rectified voltage of the rectifier is higher than the frequency of the AC power source. an apparatus for converting at an operating frequency and generating an alternating current voltage at the operating frequency; c. A step-down transformer connected to the rectified voltage converter has a pair of secondary terminals connected to the rectified voltage converter. output a voltage lower than the voltage output from the rectifying voltage converter at the operating frequency; Each secondary terminal is connected to one of each pair of welding electrodes and has a central tap. with a step-down transformer; d. connected to the secondary terminal of the step-down transformer, the center tap and the welding electrode; A full-wave rectifier for rectifying the output voltage of the step-down transformer and supplying the rectified voltage to the welding electrode. The electric circuit of a resistance welding machine consists of. 7. In the circuit according to claim 6, the AC voltage generator comprises: a. a timer that generates a rectangular pulse with a controllable pulse width at the operating frequency; a circuit; b. is connected to the timer circuit and the step-down transformer, and flows through the step-down transformer. a plurality of semiconductor devices for alternately switching current at the operating frequency; Electrical circuit of resistance welding machine. 8. In the circuit according to claim 6, the step-down transformer: a. An iron core made of ferromagnetic material; b. a primary winding surrounding the ferromagnetic core; c. Ferromagnetic material in a single water-cooled conductor A resistor consisting of a secondary winding formed by winding a steel core twice in the same direction. Welding machine electrical circuit. 9. 9. The circuit of claim 8, wherein the step-down transformer further comprises two windings. Electrical circuit of a resistance welder with a central tap at the junction of the wires.