JPS591506B2 - Method for detecting center of weld groove between surfaces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention detects the contact time between the vibrating element and the opposing surfaces, especially the left and right walls of the groove, and detects and guides the deviation between the center of the surfaces and the vibrating element holding part. The present invention relates to a method for detecting the center of a welding groove by guiding and holding a welding torch or the like at the center between the surfaces.

The inventor has previously proposed a method and a method for detecting the relative position of an object using a vibrating element, and the structure thereof will first be explained with reference to drawings.

A vibration applying device, such as a DC motor 2, which applies vibration to the vibration system, is fixed to a fixed block 1 which is a part of the detector.
An alternating current voltage is applied to the direct current motor 2 from an alternating current power source 3, and the motor shaft 4 reciprocates in accordance with the frequency of the alternating current voltage. The vibration system vibrated by this motor shaft 4 includes a center setting vibrating piece 5, a tightening jig 6 fixed to the motor shaft 4, and a vibrating piece T.
It becomes more. Depending on its shape, material, and dimensions, the vibrating piece T vibrates in a first-order mode resonance state as shown in FIG. 3 or in a second-order mode resonance state as shown in FIG. It comes into contact with either or both of the right side groove surfaces 8b and detects the center of the axis of the DC motor with respect to the groove surface or its center line, and thus the relative position of the fixed block 1 and the welding torch connected thereto. It is something. This contact between the vibrating pieces is electrically detected by electrical circuits 9 and 10, and the signals make it possible to trace the groove center line 13 of the base material 8 by the detector and by extension the welding torch and guide the displacement. An object of the present invention is to propose a suitable signal acquisition method when tracing and detecting a groove center line by contact between a vibrating piece vibrating in a resonant state and both side walls of the groove. The present invention is characterized in that the signal for detecting the tracing of the groove centerline is obtained from the ratio of the contact time during which the vibrating piece, which vibrates at resonance or near resonance, is in contact with each side of the groove.

Let us consider the time period during which the vibrating element is in contact with both left and right walls with reference to FIGS. 5 and 6.

5 and 6 are illustrated in conceptually corresponding positions for ease of understanding. The base material 8 has a groove with a width a,
The amplitude of the end of the vibrating piece T that attempts to copy and detect this is W
Suppose it was. Now, as shown in Fig. 6, we plot this as a graph of time (horizontal axis) and current i (vertical axis), and during the time when the vibrating piece is in contact and the current is flowing, the left groove surface Ba has the symbols I, It is X seconds between the openings and y seconds between C and 2 for the right side groove surface 8b. From the vibration mode of the vibrating element, the "deviation" dimension e between the vibrating element holding part center (motor shaft center) 4 and the groove center line 13 can be obtained as a signal value proportional to the angle.

It can also be detected and visually recognized using an Otsushiro scope or the like. Further, these currents can be taken out from lead wire terminals 17 and 18 by a contact state detection circuit 16 having a resistor 14 and a DC power source 15 shown in FIG. By implementing this invention, it becomes possible to detect the deviation between the welding groove center line and the vibrating element holding part as a ratio of the contact time of the vibrating element end with the left and right side wall surfaces of the groove, and the center line of the welding torch, etc. It is possible to easily correct the [deviation] from X,
Although the time y is extremely short, it is possible to electrically accurately extract a signal, thereby contributing to an improvement in detection accuracy.

[Brief explanation of the drawing]

Figure 1 is a front view of a detector with a vibrating element, Figure 2 is a side view thereof, Figure 3 is a drawing showing the primary mode vibration of the vibrating element, Figure 4 is a drawing showing secondary mode vibration, and Figure 4 is a drawing showing the vibration in the secondary mode. FIG. 5 is a drawing showing the vibration of the vibrating element and the deviation from the groove center, and FIG. 6 is related to FIG. 5 and is a drawing showing the relationship between contact current and time. 1...Fixed block, 2...DC motor, 4...Motor shaft, 7...Vibration piece, X, y...Contact time.

Claims (1)

[Claims] 1 In a method of detecting the center between opposing welding groove surfaces using a contact piece, the deviation between the center between the welding groove surfaces and the center of the holding part of the vibrating piece that vibrates in the resonance state of the detector is detected using a vibrating piece. The method is characterized in that the center between the opposing welding groove surfaces is detected by taking out as a signal the ratio of the time during which the welding groove is in contact with the left side surface of the groove and the time during which the welding groove is in contact with the right side surface of the groove. Method for detecting center of weld groove.