JPS6046874A - Profiling detector for welding - Google Patents

Abstract

PURPOSE:To stabilize detecting function without being affected by contact conditions by detecting the change in inductance from the change in the slight high- frequency current impressed preliminarily to an induction coil and enabling the detection between a wire and materials to be welded. CONSTITUTION:A titled device has a device for detecting the position of a welded joint consisting of a high-frequency bypass means CHF, an induction coil 3 and a means for detecting the changing speed of the inductance of the coil 3 generated by the contact between a welding wire 2 and materials 1 to be welded and detecting the above-mentioned contact by discriminating said speed. A closed circuit for a high frequency is formed in the above-described means CHF through the wire 2, the materials 1 and a cable 2a on the welding side when the wire 2 of a welding wire type arc welding robot or welding wire type automatic welding machine contacts the materials 1. The above-described coil 3 is provided in the above-described circuit and the inductance thereof is changed by the change in the high-frequency current impressed thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding trace detection device employing a wire sense method that can automatically confirm the position of a weld joint.

When using a welding wire type arc bath inlet or an automatic arc welding machine, apply an appropriate power source pressure between the welding wire and the material to be welded, and perform the preset steps (program). Automatically confirms the bath weld joint (bevel) position by short-circuiting between the wire tip and the surface of the welded material, detecting the change in the circuit current (resulting j14L pressure), and reading the coordinates at that time. The so-called wire sense method is adopted.

21.1 (a) and (b) show different configuration examples of the conventional wire sensing method. In the same figure (a), a single-use 'Shimogen Pw' and a wire sense terminal P8 are separately provided, and these are switched between the bath welding wire 2 and the workpiece 1 by switching them using a changeover switch. [1b3L'Mf pressure is applied. In other words, changeover switch SW is connected to contacts a-J and a-2.
The voltage of the wire sense type P8 is applied between the welding wire 2 and the welded object 1, and the circuit current (or voltage) at that time is detected by the wire sense detector Is (straight Vs
). Further, in FIG. 1(b), a welding power source pw and a welding wire 2. Connect the wire sense series resistor R8 in parallel to the power supply circuit connecting to the material to be welded 1 E7
The welding power source Pw is also used as the wire sense power source by providing a bath contact conductor C. When the welding contactor C is opened to set the wire sense state, the circuit' current (or voltage) is ) is detected by wire sense detector I (or V).

However, by switching between the mononoke wire sense power source P8 and the welding power source pw of the configuration shown in FIG. 1(a), the welding wire 2
Since the Amei pressure is applied between the terminals of the welding material 1 and the welding material 1, a changeover switch SW between the wire sense power source P8 and the welding power source Pw is required.

In addition, in the configurations shown in FIGS. 1(a) and 1(b), it is obvious that the welding wire may be damaged due to variations in the surface condition of the welding wire tip or the welding wire. There are variations in electrical contact resistance, and in order to absorb the variations, a considerable pressure must be applied. This depends on the insulation performance of the equipment and, in some cases,
It also requires special consideration for human safety.
14 complexities contribute to high costs.

The present invention alleviates these drawbacks, and provides a detector T which has a simple mechanism, is easy to install and handle, and is stable regardless of the contact state between the welding wire and the material to be welded. The object of the present invention is to provide a welding tracing detector b-= that exhibits the following characteristics.

In order to achieve such an object, the present invention uses a wire sense method in which when the tip of the bath welding wire and the material to be welded come into contact,
An elevated 17M pinosu means was installed to form a short-circuit closed circuit between the welding wire, the material to be welded, and the welding cable, and a 0-conductor coil was installed in the short-circuit to change the inductance. 0, and by detecting and discriminating the change in inductance λ* degree (change 4') caused by the change in the weak high frequency wave applied to the induction coil, the welding wire and the material to be welded can be distinguished. It has the following features:

[F] Since this is an indirect application/detection method using a high-frequency induction coil, there is a very low possibility that it will be interfered with by noise generated during operation of the main unit.

■ Installation to an existing mother machine is extremely intrusive, and there is no need for any modifications such as installation of a changeover switch as in the conventional system.

■ A high frequency oscillation circuit including an induction coil has C and It in the circuit so that the oscillation amplitude changes greatly depending on the presence or absence of contact between the welding wire and the welded material.

Since the L constant is set, the detection sensitivity is extremely high, and therefore a stable detection function can be achieved without being affected by surface excitation near the tip of the wire or the joint of the welded material.

■ Since the inductance change speed IW of the induction coil due to contact between the welding wire and the welded material is detected and discriminated, it is not affected much by the absolute value of inductance of the circuit including the nuclear detection circuit, and has excellent operability. becomes.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 2 r1 shows an example of the configuration of a welding tracing detection device according to the present invention. The same figure (al is an example of the block configuration when applying the main detection 10 seconds to a butt weld joint, 1 is the material to be welded, 2 is the welding wire, 2a is the welding 01TL cable, 3 is the induction coil, 3a is the welding material) The connecting cable, CHF', is a high frequency current detour prevention product tM H bypass capacitor. Also, 4 is a matching transformer, 5 is a characteristic W slope circuit, 6
1 is a high frequency oscillation circuit, 7 is a detection circuit, 8 is an amplitude change rate discrimination circuit, 9 is a discrimination threshold setting circuit, 10 is a discrimination result storage circuit, 11 is a discrimination display circuit, and 12 is a discrimination 6 memory reset circuit. are shown respectively. FIG. 2(b) shows a case in which a fillet welded joint is targeted, and the circuits of the detection section are the same as those in FIG. 2(a), so they are omitted.

FIG. 2(e) shows a detailed configuration of the induction coil 3 in FIGS. 2(a) and 2(b).

6- Next, FIG. 3 shows a circular streetcar circuit according to the block configuration example shown in FIG.

3a is a connection cable (corresponds to 3a in Figure 2 (a)), 4
is a matching transformer (corresponding to 4 in FIG. 2(a)), which uses a matching high-frequency transistor.

Reference numeral 5 designates a characteristic adjustment circuit (corresponding to 5 in FIG. 2) for adjusting the electrical characteristics of the high frequency circuit using a variable resistor VRJ and a variable capacitor VCJ.

6 is an oscillation circuit (corresponding to FIG. 2(a)), which has an oscillation coil. 7 is a detection circuit (corresponding to 7 in FIG. 2(a)), and in the figure, DI and D2 indicate diodes.

In the 8-digit amplitude change rate discrimination circuit (contrast with Fig. 2 (a)),
411 is made up of an integrating circuit consisting of an operational amplifier IC1 as a discrimination comparator, a resistor R and a capacitor C provided at the non-inverting input stage of the arithmetic amplifier IC1. 9
2 is a discrimination threshold setting circuit (corresponding to 9 in FIG. 2(a)), which uses a setting threshold value setting potentiometer VR2. 10 is a storage circuit for the discrimination results (corresponding to 10 in FIG. 2 (a)), which is composed of a flip-flop circuit using transistors TR3 and Tlt4. 1 is a display circuit for the discrimination results (corresponding to 10 in FIG. 2 (a)); ) corresponds to 11),
Display light emitting diode LED1. It is composed of two LEDs. 12-digit discrimination memory reset circuit (Figure 2 (a)
), the reset push button switch PR7 is used.

Next, the operation of the swamp contact tracing detection device constructed as described above will be explained.

i4', Figure 4 shows A, B, and C in Figure 3 when operated by the circuit configuration shown in Figures 2 and 3.

It shows the actual voltage measurement results at each point D, E, and F.

Fig. 4(a) shows the actual voltage measurement value at point A in Fig.
Figure 2(a) shows the situation of changes in the high-frequency oscillation pressure (amplitude) when the handling seedlings 1 and the bathing wire 2 are in contact with each other from the isolated state. represent. Same figure (b)
represents the voltage at point B in FIG. 3, which is the DC voltage detected by the high frequency voltage shown in FIG.
It shows a change in DC frost pressure corresponding to a change in the high IAU wave oscillation voltage due to contact between the welding wire 2 and the broken weld material 1. Fig. 3(e) N A situation where the detection output shown in Fig. 3(b) is applied as is as the inverting side input of the amplitude change rate discrimination comparator ICJ, that is, the application frost at the 0 point in Fig. 3. Indicates pressure.

Figure (d) shows a situation in which the detection output shown in Figure (b) is applied to the integrator circuit consisting of C and R as the non-inverting input of the amplitude change rate discrimination comparator IC1. 3
The applied voltage at point D in the figure (c) is shown.

The same figure (,) shows that the amplitude change "*-* separate comparator IC7 is such that its output becomes nli of the shellfish for the in-phase human power (A
lt Kana Offset Blood Pressure Setting The input voltage shown in (c) and (d) of FIG. , is applied to the inverting input terminal and the non-inverting input terminal, respectively, and shows the output voltage of the amplitude change rate discrimination ratio softener IC7, that is, the output voltage at point E in FIG. 3. As can be seen from the figure, the output voltage at point E in FIG. ] The pulse-like output that is positive in only the third song (-tefIIr-,)12, :f: Noye pulse width (Fig. 4(d) Δt in VC) i
f Due to the time constants of the C and R integrator circuits related to point I) in Figure 3, Ofuyo Tezawama 21° (f) in Figure 4 is shown in the same figure (el)
The output voltage of the memory circuit 0, which is triggered by the pressure A', also shows the output voltage situation at point F in Figure 3, and the clear output voltage is , I didn't pay too much attention to the changes in Shima Shuha's pressure due to contact with 1' and 2's Doha foil J, but the 7th D was the point where the impoverishment rate was large, and this was a very clear fuη. It also has the function of outputting voltage according to voltage changes. Using this output 'rk pressure, the coordinates of the welding torch are automatically entered and the correct bath joining position is memorized. In addition, the display circuit 11 is severely damaged. When the wire 2 and the exposed wire 1 are isolated (7 J), the display diode 2 and ED2 light up, and when the two come into contact, the fClμm For display! 16 yuan diode LF;
Since the DI is better than being lit, it has a four-point scale that can display the relative positional relationship between the two.

10- In this way, it is clear from the above-described embodiments that the present invention introduces a wire sensing method for molten cherry blossoms using induction application of high-frequency frost flow and inductance discrimination, so that the following effects can be obtained. You can get it.

[F] Since this is an indirect application/detection method using a high-frequency induction coil, there is an extremely low possibility of being disturbed by noise generated during operation of the main unit.

■ The installation on the existing mother machine is extremely cylindrical, and there is no need for any modifications such as installation of a changeover switch as in the conventional system.

■ The high-frequency oscillation circuit that uses an induction coil has C1R and L constants set in such a way that the oscillation amplitude changes greatly depending on the presence or absence of contact between the welding wire and the welded material, so the detection sensitivity is low. This is extremely high, and therefore a stable detection function can be achieved without being affected by the state of the surface area near the wire tip or the joint of the welded material.

In addition, iT%4 due to curved contact between the welding wire and the material to be welded
Since the inductance change rate (coil) is detected and discriminated (-), it is not affected much by the absolute value of inductance of the circuit including the circuit to be detected, resulting in excellent operability.

Furthermore, since the main parts are composed of simple analog circuits, it can not only be realized at low cost, but also provide a powerful clue to realizing labor savings in the automation and robotization of welding-related equipment. Moreover, there is also the advantage that market competitiveness is strengthened by improving the functionality and reducing costs of the Ri contact H-sut or automatic bath bath equipment.

As described above, according to the present invention, when the tip of the bath welding wire and the material to be welded come into contact in the wire sense method,
A frequency bias means is provided so that a high frequency short-circuit closed circuit is formed by the welding wire, the material to be welded, and the welding side cable, and an induction coil whose inductance changes when the closed circuit is formed is provided. Contact between the welding wire and the material to be welded is detected instantly by detecting the rate of change in inductance based on changes in the weak high-frequency current applied to the induction coil in advance, resulting in a simple mechanism. It is easy to install and handle, and it is possible to demonstrate a stable detection function regardless of the contact state between the welding wire and the welded material. It is possible to provide a welding trace detection device with excellent operability that is not affected by any influence.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) show a configuration 1 for explaining different conventional wire sensing methods. A, Figure 2 (a) to (c)
) shows one embodiment of the present invention, (a) is a block diagram when applied to a butt bath joint, (b) is a diagram when applied to a fillet welded joint, and (c) is an induction diagram. A configuration diagram showing details of the coil, FIG. 3 is a specific circuit configuration diagram of the same embodiment, and FIGS. 4(a) to (f) show voltages at various parts in FIG. 3 used to explain the operation of the same embodiment. FIG. DESCRIPTION OF SYMBOLS 1... Material to be welded, 2... Welding wire, 2&... Welding side cable, 3... Induction coil, 3a... Connection cable 13- pull, 4... Matching transformer, 5...・Characteristics adjustment circuit,
6... High frequency oscillation circuit, 7... Detection circuit, 8...
Amplitude change rate discrimination circuit, 9... discrimination threshold setting circuit,
10... Discrimination result storage circuit, 11... Discrimination display circuit, 12... Reset circuit. Applicant Sub-Agent Patent Attorney Takehiko Suzue 14-

Claims (1)

[Claims] When the bath welding wire of a welding wire type arc welding robot or welding wire type automatic arc welding machine comes into contact with the welded material, a high frequency short circuit is formed through the welding wire, the welded material, and the welding side cable. a high-frequency bypass means provided in the above-mentioned manner, an induction coil which is provided in the high-frequency short-circuit closed circuit and whose inductance changes depending on a change in the high-frequency current applied in advance, and a contact between the welding wire and the welding material. A welding joint position detection device comprising a means for detecting and discriminating the accompanying change rate of the inductance of the induction coil to instantly detect contact between the welding wire and the welded material. A welding tracing detection device characterized by: