JPS6031052A - Operating control of automatic magnetizing apparatus in magnetic flaw detection - Google Patents

Abstract

PURPOSE:To allow a contact resistance to drop, by, when a magnetic excitation current is detected with a detecting means, such as, for instance, a meter, and upon detecting increase of resistance value of the contacting area by the decrease of the magnetic excitation current, temporary release of pressing means, such as, for instance, an air ring, etc. and repressing. CONSTITUTION:When contact resistances of contact areas A under pressure of specimen 1 for inspection and electrodes 3, 3 increase, a magnetic excitation current flowing from a source 6 to the specimen 1 through the electrodes 3, 3 decreases. When this magnetic excitation current is detected with a meter-relay 7 and the magnetic excitation current drops below the specified value, a signal is given to a controller 18 pressure air applied to connecting openings 11, 11 of air cylinder 9 is switched to those 12, 12. The contact area A under pressure of the specimen 1 is released temporarily and thereafter switched again by the controller 18 and the original condition is restored by air pressure applied to the connecting opening 11. By this arrangement, a higher productivity becomes available without necessity of reduction of surplus man-hour values and interruption of continuous operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention can be used in magnetic flaw detection, which is one of the methods for inspecting the presence or absence of flaws on an object to be inspected. The present invention relates to an operation control method for an automatic magnetization device.

(Prior art) In the magnetic flaw detection method described above, magnetic flux above a certain level is passed through the object to be inspected, and when there is a flaw in the object to be inspected, leakage magnetic flux is generated from the flaw. Magnetic powder coated with fluorescent paint is applied to the surface, and the magnetic powder pattern attracted by the leakage magnetic flux is irradiated with ultraviolet rays to cause the fluorescent paint to emit light, and this is visually observed to determine whether there are any scratches. Therefore, it is necessary to always obtain a magnetic flux above a certain level in the object to be inspected, and for this purpose, the current for generating the magnetic flux must also always flow above a certain value.

By the way, as a method of applying current to the object to be inspected to generate magnetic flux, there is the following method.

■ Axial energization method in which electrodes are pressure-contacted to both ends of the object to be inspected and current is passed directly between the electrodes.

■ A split coil is placed around the outer circumference of the object to be inspected.

The coil method involves passing current through this coil.

■ The object to be inspected is a cylindrical body, and a split rod-shaped electrode is placed inside the object.

This is a current penetration method in which current is passed through this rod-shaped electrode.

■ A method that combines methods from ■ to ■ above.

In both of these methods, there is a contact part in the energized circuit,
Therefore, when the contact resistance of this part increases, the magnetizing current decreases, and the strength of magnetization weakens due to this.
A sufficient flaw detection effect will not be obtained. Specifically speaking, the contact portion corresponds to the press-contact portion between the object to be inspected and the electrode in the method (2), and the divided portion of the split coil in the method (2). In the Zarani ■ method, the contact part of the rod-shaped electrode corresponds to the contact part of the rod-shaped electrode, and these are all connected by an air cylinder etc.
This is to obtain contact pressure.

Conventionally, an ammeter is connected to two current-carrying circuits.

The decrease in magnetizing current was determined from the reading of this ammeter. For this reason, detailed monitoring could not be performed, and if left unchecked, the inspection would be defective. Therefore, if the magnetizing current is less than the set value, it is necessary to cut off the current and remagnetize with a magnetizing current equal to or higher than the set value. Therefore,
If the magnetizing current is below the set value, a buzzer or lamp indicates that the energization is defective, and at the same time automatic operation is interrupted, after which two workers perform the process of re-energizing. Therefore, each time a power failure occurs, extra work is required, and the smooth flow of work is hindered.

(Object of the Invention) The present invention has been made to solve the above-mentioned disadvantages of the prior art, and the re-energization work, which was conventionally performed by nine operators, is automatically performed. The purpose of this invention is to provide a method for controlling the operation of an automatic magnetizer in magnetic flaw detection.

(Structure of the Invention) The present invention detects a magnetizing current by a detection means such as a meter relay, and when it is detected that the resistance value of the contact portion increases due to a decrease in the magnetizing current, the control means controls the air cylinder, etc. The contact resistance is reduced by temporarily opening the suppressing means and then returning to the suppressed state again.

(Application Example of the Invention) Next, a first application example of the present invention will be explained using FIG. Reference numeral 1 denotes an object to be inspected, which is made of a magnetic material.

The object to be inspected 1 is a rod-shaped object.

It is supported in a horizontal state by mounting tables 2, 2.

Electrodes 3.3 are arranged at both ends of the object to be inspected 1,
These electrodes 3, 3 - these are bolts 4, 4 and nuts 5.
1 by 5! An electric wire 8 is connected in which a power source 6 and a meter relay 7 are connected in series.

9.9 is an air cylinder. These air cylinders9.
9. Piston rods 10, 10 protrude from the collar so that they can move forward and backward, and when compressed air is applied to the intake/discharge ports 11.11 of the air cylinders 9, 9, the piston rods 10, 10 protrude toward the object to be inspected 1, The suction/discharge ports 12 and 124 are configured to apply compressed air without drawing in the piston rod 10 and 10. The aforementioned electrode 3.3 is attached to the tip of the piston rod 10.10 with a bolt 13.

The suction/discharge ports 11, 11 and the suction/discharge ports 12゜12 of the air cylinders 9, 9 are commonly connected by an N pipe 14.15, and these are connected to the connection port 19 on the output side of the controller 18 by a pipe 16.17. .20 J is connected. A near compressor 22 is connected to a connection port 21 on the input side of the controller 18 . When the controller 18 receives the control signal, the controller 18 connects the connection port 2.
The control system selectively communicates with one of the two connection ports 19 and 20 for 1, and the control system is connected to the
Connected to meter relay 7.

In such an apparatus, the method of the present invention is realized as follows. That is, the meter relay 7 is set to a current value ζ sufficient to generate an appropriate magnetic flux in the object 1 to be inspected. With this setting, if there is no abnormality in the two circuits, the current from the power source 6 flows through the electric wire 8 and the electrode 3 to the test object 1. The object to be inspected 1 is appropriately magnetized by this current.

If you apply magnetic powder coated with fluorescent paint on its surface.

If there is a scratch, magnetic particles will be attracted to the scratch site due to leakage magnetic flux generated from the scratch site.

Flaw detection can be performed by irradiating the object 1 to be inspected with ultraviolet rays to cause the fluorescent paint applied to the magnetic particles to fluoresce, and visually observing the pattern of the magnetic particles.

Now, when the contact resistance of the pressure contact part A between the test object 1 and the electrodes 3, 3 increases, the magnetizing current flowing from the power source 6 through the electrodes 3, 3 to the test object (2) decreases. If this is left as is, the magnetization of the object to be inspected 1 will be insufficient, and small flaws will not be found. Therefore, in the method of the present invention, the decrease in magnetizing current is detected by the meter relay 7.

When the magnetizing current becomes smaller than the value preset in the meter relay 7, a signal is sent to the controller 18, which connects the air cylinder 9 to the connection port 11. Now switch the compressed air that was being applied to 11 to connection 1j 12.12. Inspection object 1
After the pressure contact part A is once opened, it is switched again by the controller 18.

The compressed air applied to the connection port 11 restores the original state.

This switching is carried out temporarily, but as a result, both ends of the object to be inspected are hit strongly once, which slightly changes the contact position with the electrode 3. As a result, a good magnetization state can be obtained upon re-energization. Hereinafter, this action will be performed automatically when the magnetizing current decreases, and a good magnetization state will always be obtained.

FIG. 2 shows a second application example of the present invention. In this case, on the outer periphery of the object to be inspected 1 supported on the stage 2.

A split-type coil 26 consisting of a lower coil 24 and an upper coil 25 is provided, and the upper coil 25 is opened upward with a shaft 27 as its center (see broken line).

This opening and closing is performed by a piston rod 10 that protrudes and retracts from the air cylinder 9. Since the control system of the air cylinder 9 is the same as that shown in FIG. 1, illustration thereof is omitted.

In this application example, the lower coil 24 and the upper coil 2
When the contact resistance of pressure contact part A of No. 5 increases and the magnetizing current decreases below a certain value due to this.

The signal l emitted by the meter relay 7 causes the air cylinder 9
is activated, the upper mold coil 25 is temporarily opened from the lower mold coil 24, and immediately after that, it is brought into pressure contact with the lower mold coil 24 again, thereby eliminating poor contact at the pressure contact part A.

FIG. 3 shows a third application example of the present invention. In this case,
In this case, where the inspected object 1 is a cylindrical body, a ring-shaped mounting table 21 is used, and the inspected object 1 and the mounting table 2 are connected to each other, and a rod-shaped lower electrode 28 and an upper electrode 29 are connected to each other. It is inserted from above and below and is pressed at pressure contact part A. As the pressure contact means, an air cylinder similar to that shown in FIG. 1 is used, so illustration of one is omitted. In addition.

In this application example, the lower type electrode 28 or the second type electrode 29 can be fixed, and only one air cylinder can be used.

(Effects of the Invention) The present invention is a method for controlling the operation of an automatic magnetization device in the magnetic flaw detection method as described above.

Since it is possible to eliminate the manual operations that were conventionally required due to the occurrence of energization failures, it is possible to reduce unnecessary man-hours and eliminate interruptions in the smooth flow of work, thereby improving productivity. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a first application example of the method of the present invention. FIG. 2 is a system diagram of a second application example of the method of the present invention. FIG. 3 is a system diagram of the main parts of a third application example of the method of the present invention. 1...Object to be inspected 3...Electrode 6...Power source 7...Meter relay 9...Air cylinder 10...Piston rod 18
...Controller 22...Near compressor 24...
Lower coil 25... Upper coil 28... Lower electrode 29... Upper electrode patent applicant Toyota Motor Corporation Sai1 Toya 2 Figure

Claims (1)

[Claims] (1) In the magnetic flaw detection method, when it is detected that the contact resistance of the contact portion of the electrical circuit for generating the magnetic flux flow has increased, and the contact resistance has increased. The contact portion is once opened to form an open circuit, and then closed to form an electric circuit again. A method for controlling the operation of an automatic magnetizer in a magnetic flaw detection method, characterized in that control is performed so that the magnetic flux flow is obtained at a predetermined level by lowering the contact resistance of the contact portion.