CN1557600A

CN1557600A - Device for monitoring working condition of spot welding head when directly welding enameled wire

Info

Publication number: CN1557600A
Application number: CNA2004100152231A
Authority: CN
Inventors: 杨仕桐; 李言亮; 刘梦华
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-19
Filing date: 2004-01-19
Publication date: 2004-12-29
Anticipated expiration: 2024-01-19
Also published as: CN100340368C

Abstract

The present invention relates to welding and electronic industry, and provides one monitor for direct enameled wire welding spot welding head. The monitor consists of current transforming coil, signal processing circuit, A/D converter, CPU, control circuit, display circuit and/or alarm system and other parts. The present invention monitors the contact resistance of welding head indirectly via measuring output current. In case that the welding head contact resistance exceeds some value to affect the welding quality, the monitor will display the work state of the welding head and/or send out alarm signal, so that the operator may repair or replace welding head to ensure the welding quality. The present invention provides one simple but practical monitor of welding head work state.

Description

Directly weld the apparatus for monitoring working state of enamel-covered wire electric welding head of pinpoint welding

Technical field

The present invention relates to welding and electronics industry, for the duty of directly welding the enamel-covered wire electric welding head of pinpoint welding provides a kind of monitoring device.

Background technology

Mention direct welding enamel-covered wire electric welding head of pinpoint welding among the patent of invention 01114808.X, the tip of soldering tip makes≤Ohmic contact of 200m Ω.The course of work of soldering tip welding enamel-covered wire is as follows: weldment (pins of enamel-covered wire and electronic devices and components) is made lap joint, and with the soldering tip pressed joint, set these three welding parameters of voltage pulse output, time and welding pressure, when welding pressure reaches setting value, trigger switch, the conducting electric current.The soldering tip tip because the insulating barrier on the enamel-covered wire, electric current are all flowed through makes the most advanced and sophisticated electric spark that produces of soldering tip, and an insulated paint part that contacts with soldering tip is burnt, and remainder is shunk back to two ends, the copper core in the exposed enamel-covered wire.Under the acting in conjunction of welding pressure and resistance heat, the arc surface of copper core is driven plain, and the salient point on the pin is also by conquassation, realizes that same pulse finishes paint removal and welding.

Can know from the structure of above-mentioned soldering tip and the course of work of soldering tip, every welding once, the tip of soldering tip all can produce electric spark with burn off insulated paint.When welding surpasses certain quantity, the contact resistance at soldering tip tip is certain to change, and this changing value surpasses when a certain amount of, will influence welding quality even influence the use of soldering tip, therefore be necessary to monitor the contact resistance at soldering tip tip, but the structure of measured resistance value is more loaded down with trivial details, and is particularly with the precision measure resistance value of milliohm level, higher to the requirement of measuring instrument.If the structure of directly measuring the most advanced and sophisticated contact resistance value of soldering tip is installed on the welding machine, will makes the structure of welding machine very complicated.

Summary of the invention

The objective of the invention is provides a kind of monitoring device for the duty of directly welding the enamel-covered wire electric welding head of pinpoint welding, when the most advanced and sophisticated contact resistance value of soldering tip surpasses certain limit, influences the words of welding quality, device can show the duty of soldering tip, or send warning signal, or show the duty of soldering tip simultaneously and send warning signal, remind the operator to change or the maintenance soldering tip, guarantee welding quality.

In order to achieve the above object, the apparatus for monitoring working state that the present invention directly welds the enamel-covered wire electric welding head of pinpoint welding by electric current mutual inductor, signal processing circuit, comparator, A/D converter, central processor CPU, control circuit, display circuit or/and warning system form, the electric current mutual inductor is wrapped on the output cable of mash welder output pulse transformer, be connected on the CPU by signal processing circuit, comparator then, the CPU periphery connects control circuit, display circuit and warning system respectively, also is connected to the end of oppisite phase of comparator by A/D converter.

Apparatus of the present invention are provided with the electric current mutual inductor on the output cable of mash welder output pulse transformer, output cable conducting electric current when output pulse transformer, mutual inductor produces induced electromotive force, this induced electromotive force is through signal processing circuit and CPU, can measure the magnitude of current of each pulse output, the actual electrical flow I when this pulse output is exactly the soldering tip welding.Then, according to the parameters of soldering tip, soldered enamel-covered wire and substrate, the magnitude of current mean value I when setting obtains best welding effect ₀And Δ I, work as I ₀-Δ I≤I≤I ₀During+Δ I, for the contact resistance value at soldering tip tip in normal range (NR), promptly soldering tip is in the normal operating conditions; As I＜I ₀-Δ I or I＞I ₀During+Δ I, be the contact resistance value overrun at soldering tip tip, when soldering tip was in abnormal state, CPU sends instruction made alarm produce alarm signal or/and display is shown, at this moment, need more renew soldering tip or soldering tip is carried out maintenance process.

The factor that influences welding quality is a lot, except the contact resistance at soldering tip tip, other is such as the size of voltage pulse output, time, three welding parameters of welding pressure and enamel-covered wire, and the coating of welded part is different with material, thickness etc., can have influence on welding quality.But during with a kind of workpiece, the substrate of the line of enamel-covered wire footpath and welded piece all is constant in welding, and three welding parameters are predefined, changes so principal element is the contact resistance value at soldering tip tip.According to Ohm's law R=V/I, because output voltage V is set quantitative, if soldering tip contact resistance R changes, output current I also can change certainly, this inversely prroportional relationship that is changed to; When directly the electric welding head of pinpoint welding work of welding enamel-covered wire was undesired, altering a great deal of its most advanced and sophisticated contact resistance value often changed with multiple, causes output current to change significantly; Owing to directly measure the structure more complicated of the most advanced and sophisticated contact resistance of soldering tip, and the structure of measurement output current is just fairly simple.Therefore, the present invention adopts and measures the contact resistance of output current with indirect monitoring soldering tip tip, thereby the duty of monitoring soldering tip becomes simply challenge.When point welding machine welding head makes soldering tip two interelectrode contact resistances become big owing to access times surpass some, install demonstration at once or/and report to the police, operating personnel in time change or keep in repair soldering tip, guarantee welding quality.

Description of drawings

Fig. 1 is the electric welding head of pinpoint welding apparatus for monitoring working state block diagram that directly welds enamel-covered wire.

Fig. 2 is the main circuit connection layout that directly welds the electric welding head of pinpoint welding apparatus for monitoring working state of enamel-covered wire.

Fig. 3 is the display circuit connection layout that directly welds the electric welding head of pinpoint welding apparatus for monitoring working state of enamel-covered wire.

Among Fig. 1, directly the electric welding head of pinpoint welding apparatus for monitoring working state of welding enamel-covered wire by electric current mutual inductor 1, signal processing circuit 2, comparator 3, A/D converter 7, central processor CPU, control circuit 4, display circuit 5 or/and warning system 6 form, electric current mutual inductor 1 is wrapped on the output cable of mash welder output pulse transformer, be connected to CPU by signal processing circuit 2, comparator 3 then, the CPU periphery connects control circuit 4, display circuit 5 respectively or/and warning system 6, also is connected to the end of oppisite phase of comparator 3 by A/D converter 7.

Among Fig. 2, directly the main circuit of the electric welding head of pinpoint welding apparatus for monitoring working state of welding enamel-covered wire connects as follows: electric current mutual inductor L1 is wrapped on the output cable of mash welder output pulse transformer T1, connect the signal processing circuit be made up of arithmetic unit U1-A and UI-B then, enter the in-phase end of comparator U1-C through resistance R 5, the output of comparator U1-C is connected to the 35th pin of central processor CPU through resistance R 6; The 37-39 pin of CPU connects the circuit of display driving that U6, transistor Q2-8 form by socket JA, the 1-6 pin of CPU connects the coding assignment device U5 of display circuit by socket JB, CPU the 7th, 8, the 12-15 pin connects A/D converter U2, the output of A/D converter U2 is connected to the end of oppisite phase of comparator UI-C by resistance R 7; The 21st pin of CPU is connected with the 27th pin by K switch 1, and the 26th pin is connected with the 27th pin by K switch 2, and the 21st pin is connected with the 26th pin by K switch 3, and the 21st pin is connected with the 25th pin by K switch 4, constitutes control circuit; The 10th pin of CPU connects the warning system of being made up of transistor Q10 and buzzer B1.U2 can adopt MAX549; U3 can adopt AT89C52.

Among Fig. 3, directly the display circuit of the electric welding head of pinpoint welding apparatus for monitoring working state of welding enamel-covered wire connects as follows: 7 display circuits that are made of display CNT0-6 and transistor Q2-8, the 1-7 pin of its display CNT0-6 is connected with coding assignment device U5 respectively, the base stage of transistor Q2-8 connects U6 respectively, and colelctor electrode connects power supply VCC; The 36th pin of CPU is by the base stage of resistance R 16 connection transistor Q9, and the colelctor electrode of transistor Q9 connects the 5th pin of display CNT0-6, and the emitter stage of transistor Q9 is understood the emitter stage of transistor Q2-8.Coding assignment device U5 can adopt CD4543; U6 can adopt MN74HC138N.

Claims

1, a kind of apparatus for monitoring working state of direct welding enamel-covered wire electric welding head of pinpoint welding, it is characterized in that this device is by electric current mutual inductor (1), signal processing circuit (2), comparator (3), A/D converter (7), central processor CPU, control circuit (4), display circuit (5) is or/and warning system (6) composition, electric current mutual inductor (1) is wrapped on the output cable of mash welder output pulse transformer, then by signal processing circuit (2), comparator (3) is connected to CPU, the CPU periphery connects control circuit (4) respectively, display circuit (5) and warning system (6) also are connected to the end of oppisite phase of comparator (3) by A/D converter (7).

2, a kind of apparatus for monitoring working state of direct welding enamel-covered wire electric welding head of pinpoint welding as claimed in claim 1, the physical circuit that it is characterized in that this device is connected to: electric current mutual inductor L1 is wrapped on the output cable of mash welder output pulse transformer T1, connect the signal processing circuit be made up of arithmetic unit U1-A and UI-B then, enter the in-phase end of comparator U1-C through resistance R 5, the output of comparator U1-C is connected to the 35th pin of central processor CPU through resistance R 6; The 37-39 pin of CPU connects the circuit of display driving that U6, transistor Q2-8 form by socket JA, the 1-6 pin of CPU connects the coding assignment device U5 of display circuit by socket JB, CPU the 7th, 8, the 12-15 pin connects A/D converter U2, the output of A/D converter U2 is connected to the end of oppisite phase of comparator UI-C by resistance R 7; The 21st pin of CPU is connected with the 27th pin by K switch 1, and the 26th pin is connected with the 27th pin by K switch 2, and the 21st pin is connected with the 26th pin by K switch 3, and the 21st pin is connected with the 25th pin by K switch 4, constitutes control circuit; The 10th pin of CPU connects the warning system of being made up of transistor Q10 and buzzer B1; By 7 display circuits that display CNT0-6 and transistor Q2-8 constitute, the 1-7 pin of its display CNT0-6 is connected with coding assignment device U5 respectively, and the base stage of transistor Q2-8 connects U6 respectively, and colelctor electrode connects power supply VCC; The 36th pin of CPU is by the base stage of resistance R 16 connection transistor Q9, and the colelctor electrode of transistor Q9 connects the 5th pin of display CNT0-6, and the emitter stage of transistor Q9 is understood the emitter stage of transistor Q2-8.