CN86203636U

CN86203636U - Vortex flaw-sensing detector

Info

Publication number: CN86203636U
Application number: CN 86203636
Authority: CN
Inventors: 黄兴运; 邵尔玉
Original assignee: LUOYANG POLYTECHNICAL COLLEGE
Current assignee: LUOYANG POLYTECHNICAL COLLEGE
Priority date: 1986-05-30
Filing date: 1986-05-30
Publication date: 1987-04-22

Abstract

The utility model relates to a new vortex flaw detection sensor, which is used for lossless detection of dynamic detection and has good electric parameters. The vortex flaw detection sensor is formed by combining an excitation coil and at least two detecting coils, and the number of the detecting coils is an even number, windings of coils all use magnetic materials as magnetic cores, and the centers of the detecting coils are positioned on the circumference line of an inner circle of the excitation coil and are put symmetrically. The utility model improves the coupling between the excitation coil and the detecting coils, increases the density of electric vortexes, has wider bands of frequency and is suitable for the dynamic detection of contact fatigue flaws of vertexes which have high load and high liner speeds and use organic oil as cooling media.

Description

Vortex flaw-sensing detector

The utility model belongs to point sensor, is used for dynamic eddy current test.

At present, traditional point type eddy current test sensor possesses three kinds of structures substantially both at home and abroad: unicoil winding " absolute type " (Fig. 1), triple coil " magnetic variation type " (Fig. 2) reaches " electricity difference formula " and compares sensor (Fig. 3 a, b) certainly, its common trait is a little less than being coupled between drive coil and magnetic test coil winding, coefficient of mutual inductance is little, and vortex density is low.Because the restriction of nondestructive inspection parameters, the electrical quantity of sensor can not control to optimum condition, influences the sensitivity of sensor, and noise is resolution when.Moreover the back two kinds of sensors that are mainly used in eddy current test all possess difference around then organizing the magnetic material processing difficulties, and the difficulty at zero point is exported in debugging " difference ", and frequency band is narrow, the rejection rate height.More outstanding for special occasions and miniature transducer the problems referred to above.The clear 56-163450 of document proposed structure be the center of juxtaposed two magnetic test coils on two drive coil inner peripherys, and be eddy current test sensor on the inner periphery line of the two coil outside, improved vortex density.Because this type of sensor only uses the coil winding volume big, magnetic permeability mu, quality factor q, inductance L, magnetic field intensity H, magnetic induction density B and magnetic flux are all lower.Because the inboard induced potentials of adjacent two groups of drive coils are cancelled each other, and vortex density is reduced, and this sensor only is applicable to manually detecting at a slow speed of sheet material, can not be suitable for the high speed detection of dynamic.

The purpose of this utility model is, a kind of detection of dynamic that is used for is provided, and structure is new, volume and flaw detection size variable, the novel eddy current test point sensor that Non-Destructive Testing and electrical quantity are taken into account.

The purpose of this utility model, be by adopting a drive coil winding and two or more a even number of doing the magnetic core coiling by the semiconductor ferromagnetic material to realize afterwards by the magnetic test coil winding combination of magnetic core coiling respectively, the center of magnetic test coil places the interior round contour of drive coil winding and by on the intersection point between the straight line in the center of circle, forming per two magnetic test coils is one group, and symmetry is put.For two above magnetic test coils, symmetry is put (Fig. 5) between will organizing simultaneously.Drive coil and magnetic test coil magnetic core, the magnetic core of selecting for use same material to do.The center of magnetic test coil places on the inner periphery line of the most concentrated winding coil of the excitation winding magnetic line of force, has improved vortex density.The ferromagnetic semiconductor material that drive coil and magnetic test coil winding adopt several metal oxides to form is made magnetic core, this type of soft magnetic material has high resistivity, its magnetization curve and magnetic hysteresis loop are keeping high permeability in very wide frequency band, the area of magnetic hysteresis loop is very little, characterizes Ferrite Material and have eddy current loss hardly in audio frequency, high-frequency range.

Advantage of the present utility model is to adopt the sensor of magnetic core coiling to have high magnetic permeability, high saturated magnetic induction, the small size under high quality factor, the same parameter.Satisfying under the nondestructive inspection parameters prerequisite, electrical quantity is compared with common sensor, the Q value improves 2-3 doubly, distributed capacitance reduces 1/2-1/3, and inductance value improves 1 times is improved the sensor comprehensive parameters, and the frequency band of broad is arranged, winding greatly can both be at the frequency band interior resonance that is adapted on excitation frequency, processing technology simple " difference " zeroing is easy in addition, and the yield rate height can be about 95%.Such sensor has been used in high linear speed, top load, contact fatigue crackle detection of dynamic under the lubricating oil bad working environments is arranged, also be suitable for simultaneously black, the non-ferrous metal tumbler of any systematicness of other industry, rotate the dynamic flaw detection and the vibration detection of sample etc. on axle class, roller class, wheel class and the various testing machine.Be description of drawings below:

Fig. 1,2,3 is the structural representation of traditional eddy current test point sensor, and wherein Fig. 1 is " absolute type " unicoil winding sensor, and Fig. 2 is " magnetic variation type " sensor of excitation winding difference.Fig. 3 (a) (b) has provided " electricity difference formula " and has compared sensor certainly.Fig. 4 is the weakness that two groups of indicated drive coil structures of clear 56-163450 exist, and the two field coil sides adjacent magnetic lines of force are cancelled each other, and reduce vortex density.Fig. 5 is the structural representation of the indicated novel eddy current test sensor of our utility model, and a is the excitation magnetic core, and a ' a ' is two magnetic test coil magnetic cores.The right side is a section of structure, and Fig. 6 has disclosed the principle that novel sensor coiling data should be followed.The number of turn (N) is the very few sensitivity and the quality factor that all can influence sensor too much.

Further illustrate content of the present utility model below by embodiment.At first select different magnetic cores according to the excitation frequency scope of using.The core diameter of excitation winding and the ratio that detects the winding coil core diameter are followed following principle: two or two above even number magnetic test coils be centre distance in twos, comprises the thickness of two coils, equals the external diameter of drive coil magnetic core.The proportionality principle of two core length is, under the prerequisite that is satisfying nondestructive inspection parameters and processing permission, the magnetic test coil core length is short as far as possible, and the suitable sensor bulk of drive coil magnetic core requires and decides.The coiling data of sensor are one has the curve (Fig. 6) of extreme value should select middle flat, too much very few all desensitizations and Q value.According to different flaw detection dimensional requirements, can encourage and detect the different size combination of winding flexibly.The winding that debugging is good is enclosed fixedly skeleton, carries out outer lead and can use through demarcating.

Claims

1, novel eddy current test point sensor, by drive coil, compositions such as magnetic test coil are on the interior round contour that is centered close to the drive coil winding of magnetic test coil.Feature of the present utility model is that drive coil and magnetic test coil adopt the magnetic core coiling respectively.And on the drive coil and put two or more even number magnetic test coils.

According to right 1 described sensor, it is characterized in that 2, the even number magnetic test coil is finally formed " difference " connection, per two magnetic test coils are one group, and symmetry is put, and are also symmetrical between group and group.And one group of magnetic test coil of every symmetry, the center of its two magnetic core put with crossing two intersection points of straight line by the drive coil magnetic core center of circle (drive coil center) and magnetic core cylindrical contour (the inner periphery line of drive coil) on.The position of even number magnetic test coil on drive coil magnetic core cylindrical contour is the five equilibrium symmetry.

3, sensor according to claim 1 and 2 is characterized in that, the distance between every group of magnetic test coil two core center equals (comprising two magnetic test coil thickness) diameter of drive coil magnetic core.

4, sensor according to claim 1 and 2 is characterized in that, drive coil and magnetic test coil select for use ferromagnetic semiconductor material of the same race to make magnetic core.By the flexible combination of different size magnetic core, form different effective flaw detection sizes.