JP2524758Y2 - Pole-type magnetic flaw detector - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gap type magnetic flaw detector used for nondestructive inspection of magnetic materials such as welded steel structures.

[0002]

2. Description of the Related Art A gap type magnetic flaw detector for conducting a magnetic particle flaw detection or the like has a magnetic pole of the apparatus facing a portion to be inspected such as a welded portion of a steel structure, and magnetizes the portion to be inspected. By spraying liquid magnetic powder or the like on the portion, it is intended to inspect the structure for defects from the accumulation of the magnetic powder. Such a gap-type magnetic flaw detector is stopped at the inspection position for inspection, moved to the next inspection position after the inspection is completed, and used while repeatedly moving and stopping. It has a structure. For this reason, conventionally, a fixed caster has been attached to the tip of the magnetic pole as a moving mechanism.

However, in such a conventional moving mechanism, the caster needs to protrude from the tip of the magnetic pole to some extent in order to be movable, and the case where the surface of the object to be inspected is not a flat surface. For this reason, a gap of usually 2 mm or more was provided between the magnetic pole and the surface of the inspection object. For this reason, the result was that the magnetic flux density entering the inspected portion of the material was significantly reduced. For example, if the gap between the magnetic pole and the test piece is 2 mm, the magnetic flux density is 20% or less as compared with the case where both are in close contact. As a result, there has been a problem that the inspection capability of the device, such as the range that can be inspected, is reduced, and the inspection efficiency is poor. On the other hand, if the capacity of the magnetic pole is increased in consideration of such a decrease in the magnetic flux density, the value of the device is greatly increased, and the overall weight is increased, so that the operability is deteriorated.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems in the prior art and to provide a gap type magnetic flaw detector which does not decrease the magnetic flux density and has a high inspection efficiency.

[0005]

According to the present invention, in order to solve the above-mentioned problems, an inter-pole type magnetic flaw detector is provided with at least two pairs of an N pole and an S pole which magnetize an object to be inspected when energized. Magnetic poles , and the tips of the magnetic poles are substantially the same.
Magnetic poles arranged to be located on one plane, and the magnetic poles
A support member for supporting integrally, said a spring supporting member for supporting the said the said spring at a gap from the surface of the object to be inspected at the time of stopping energization with a rotating body rolling surface of the object support And a structure that supports the magnetic pole via a member , wherein the gap is a gap where the magnetic pole is attracted to the inspection object against the force of the spring when current is supplied.

[0006]

According to the present invention, since the magnetic pole is supported by the spring, the magnetic pole is movable in the direction of expansion and contraction of the spring. When the power supply is stopped, the magnetic pole is supported by the structure via the spring and the support member with a gap between the inspection object,
In addition, since the structure includes the rotating body that rolls on the surface of the inspection object, the magnetic pole is easily moved on the inspection object.
On the other hand, when the magnetic pole is energized, it becomes a magnet, magnetizes the object to be inspected, and generates a magnetic attractive force between the magnetic pole and the object to be inspected. At the time of energization, the gap between the magnetic pole and the test object is
Since there is a gap in which the magnetic pole can be attracted to the test object against the force of the spring, when a current is applied for magnetically flaw-detecting the test object, the magnetic pole and the test object necessarily adhere to each other due to the magnetic force. As a result, the test object is magnetized without decreasing the magnetic flux density. That is, according to the present invention, both ease of movement and high density of magnetic flux at the time of inspection are satisfied, and inspection efficiency is improved. In this case, the spring force is generated as a resistance in proportion to the distance of extension of the spring with respect to the magnetic attraction force when energized, so that the impact force when the magnetic pole is attracted to the inspection object is reduced. Be relaxed. Also, few
At least two pairs of each magnet are supported integrally
Therefore, the oscillation and vibration of each magnet are reduced,
Stability is improved.

[0007]

FIG. 1, FIG. 2 and FIG. 3 show the structure of a gap type magnetic flaw detector of an embodiment, and are respectively a front view, a plan view and a side view. The present inter-pole magnetic flaw detection apparatus has at least two pairs of magnetic poles N ₁ , N ₂ , and S ₁ each of which includes an N pole and an S pole that magnetize an object to be inspected, for example, the welded structure 1 when energized. , a four-pole magnetizer 2 consisting of S _2, a spring 3 is a spring for supporting the magnetizer 2, from the surface 1a during deenergization provided with casters 4 as a rotating body rolling on the surface 1a of the welded structures 1 And a movable carriage 5 as a structure for supporting the magnetizer 2 via the spring 3 with a gap δ therebetween.

[0008] magnetizer 2, hanging four core 2b at the bottom of the U-shaped cores 2a of the support member, the structure winding the coils on the core _2b, N _{1, N} 2,
It is composed of four poles S ₁ and S ₂ . The iron core 2b has a cross-sectional dimension of 25 mm × 25 mm, and the gap is 140 mm between NS and 100 mm between NN. 4 poles
The tip of each iron core 2b is located on almost the same plane
Swelling. Then, by inputting an AC power supply to the magnetizer 2, a range of an ellipse having a major axis of 100 mm and a minor axis of 65 mm can be reliably inspected.

The spring 3 is moved from the movable carriage 5 to the flange 6
The lower end is supported by a nut 8 and the upper end is pressed against a projection 9a of a U-shaped member 9 supporting an iron core 2a. The magnetizer 2 is elastically supported by the movable carriage 5. There are three support points. When no power is supplied to the magnetizer 2, there is a gap δ between the tip of the iron core 2b and the surface 1a of the welded structure 1. The gap δ may be a dimension that allows the magnetizer 2 to move without hitting the welded structure 1 or the like, even when the surface of the inspected object such as the welded structure 1 is not locally flat. It is. With such a gap, when power is supplied to the magnetizer 2, the magnetizer 2 becomes an electromagnet, and the magnetic force generated between the magnetizer 2 and the welding structure 1 causes the iron core 2 b to form the welding structure 1. It can be adsorbed and adhered to the surface 1a.

The main part of the movable carriage 5 is constituted by a base plate 5a and a pillar 5b, and a caster 4 is attached to a lower end of the pillar 5b. The caster 4 is a free caster that rotates 360 °. Also, the handle 1 has a handle 1
0 is attached. With such a structure, the movable carriage 5 can move in an arbitrary direction when the power supply is stopped.
As a result, the apparatus can be easily moved as compared with the conventional fixed caster, and the inspection efficiency is also improved in this respect as compared with the conventional one. The movable cart 5 is further provided with a magnetized power supply relay box 11. Then, the magnetizing power supply can be turned on / off by the switch 11a attached thereto.

With such a structure, the present pole-to-pole magnetic flaw detector is used as follows. For example, the present apparatus is set so that the N pole and the S pole straddle the inspection target portion of the inspection object such as the welded portion of the welded structure 1, and the power of the magnetization power supply relay box 11 is turned on and the magnetizer 2 is turned on. At the same time, the test liquid composed of wet-type fluorescent magnetic powder is sprayed on the inspection target portion. By this energization, the magnetizer 2 comes into close contact with the welded structure 1 by magnetic force, and magnetizes the welded structure 1 in a certain area range from the surface of the welded structure 1 to a certain depth from the surface. As a result, if there is any defect in the inspection target range of the welded structure 1, the magnetic field lines are interrupted at the defective portion, the magnetic flux leaks, and the magnetic particles move to collect at the defective portion, so that such a defect is detected. You. In this embodiment, the combination of the magnetic poles is N ₁ -S ₁
And N ₂ −S _2, and the power supplied to them is sequentially switched, so that all the defects in the 360 ° direction can be detected.

In this case, since the magnetizer 2 is in close contact with the welded structure 1, the magnetic flux density entering the welded structure 1 does not decrease, so that the inspection accuracy is improved and the inspection range can be widened. it can. For example, in a conventional apparatus in which a caster is attached to a magnetic pole and a gap of about 2 mm is provided between the magnetic pole and the inspection surface, the limit of the inspection range is 60 m with a 220 V AC power supply.
In contrast to m × 60 mm, in the apparatus of the example, it was confirmed by an experiment that the testable range was 100 mm × 65 mm or more even with a magnetic pole of the same size and a power supply voltage of 160 V.

Next, when the inspection of a certain range is completed, the power supply to the magnetizer 2 is turned off. Thereby, the magnetizer 2
The magnetic force between the welding structure 1 and the magnet 1 disappears, and the repulsive force of the spring 3 pulls the magnetizer 2 away from the surface 1a of the welding structure 1 to form a gap of 2-3 mm therebetween. The gap allows the device to be easily moved with the handle 10. When the apparatus is moved to the next inspection area, the apparatus is stopped there, the power is turned on again, the magnetizer 2 is brought into close contact with the welded structure 1, and the inspection is performed in the same manner. By repeating such an inspection / movement, a magnetic particle flaw inspection inspection of the entire inspection target is performed.

According to the inspection method as described above, the inspection range is widened because the welded structure 1 and the magnetizer 2 are in close contact with each other, and there is a sufficient gap at the time of movement, and the inspection is easy. Efficiency is greatly improved. In the related art, two inspectors are used as a single set to perform the inspection. However, the apparatus according to the present embodiment enables the inspection by one person.

In the above, the case where a person operates and moves the gap type magnetic flaw detection apparatus has been described.
The present invention can also be applied to a case where the operation and movement of the device are automated.

[0016]

[Effects of the Invention] As described above, according to the present invention, the tip is almost
Since at least two pairs of magnetic poles are provided on the same plane, defects which may exist in all directions within a certain planar inspection range can be inspected at once. In addition, since the magnetic pole can be brought into contact with the inspection object at the time of inspection, a decrease in magnetic flux density can be prevented, and the inspection capability can be improved by expanding the inspection range. In particular, in an apparatus in which the magnetizer is strong and has multiple poles and is large, there is a great effect in reducing the overall weight and the apparatus and inspection costs. Further, since the magnetic poles are supported via the springs, the magnetic attraction force when energized is reduced by the resistance of the springs, thereby preventing the magnetic poles from coming into contact with the inspection object. Since the contact between the magnetic pole and the object to be inspected occurs every time a certain range of the inspection surface is inspected, the contact is repeated innumerably. Wear is prevented. Further, when the magnetic pole is covered with an epoxy resin or the like, breakage of the coating material such as the epoxy resin is prevented. Further, by reducing the impact force, adverse effects on electric equipment such as a power supply unit which is usually provided integrally are eliminated, and troubles such as failures do not occur. On the other hand, if the power supply is stopped when the inspection is completed, the magnetic pole is automatically separated from the surface to be inspected by the spring force. Therefore, if the spring force is used in this way, even if the magnetic poles are brought into contact / separation at the time of inspection, only the operation of turning on / off the power supply is sufficient, so that there is no need for any extra operation as compared with the conventional device. Operability is not reduced. And this place
At least two pairs of each magnet are supported
Of each magnet during transportation, etc.
And vibration are reduced, the stability is good and the operability is good,
Inspection efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a gap type magnetic flaw detector according to an embodiment.

FIG. 2 is a plan view of the device.

FIG. 3 is a side view of the device.

[Explanation of symbols]

2 Magnetizer (magnetic pole) 2a Iron core (supporting member) 3 Spring (spring) 4 Caster (rotating body) 5 Moving trolley (structure)

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigenobu Miyagawa 1 Kawasaki-cho, Sakaide-shi, Kagawa Prefecture Kawakami Inspection Service Co., Ltd. (56) References JP-A-1-316655 (JP, A) JP-A Heihei 4-140658 (JP, A) Fully open Hei 4-99065 (JP, U) Really open Showa 63-195253 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] At least two pairs of magnetic poles comprising an N pole and an S pole for magnetizing an object to be inspected when energized ,
The tips of the magnetic poles are located substantially on the same plane.
Magnetic poles arranged in a row, and a support for integrally supporting the magnetic poles
A member, a spring supporting the support member, and a rotating body that rolls on the surface of the object to be inspected, wherein the spring and the support member are separated from the surface of the object to be inspected when power is stopped. And a structure that supports the magnetic pole through the gap, wherein the gap is a gap where the magnetic pole is attracted to the object to be inspected against the force of the spring when energized. Magnetic flaw detector.