DE102020106482B3 - Inductor device for the thermal detection of cracks in the area of the surface of metallic components - Google Patents

Abstract

In an inductor device (100) for heat excitation of a test object (200) by generating an eddy current inside an electrically conductive test object (200) with an inductor body (110) in the form of at least one U-profile, in which two opposing legs (120 , 130) are connected to one another via an inductor base, an adaptation to the shape of individual test objects (200) is made possible by the fact that the relative orientation of the respective end faces (122, 132) of the two free ends (121, 131) of the opposite Legs (120, 130) descriptive angle depending on the size and shape of the test area is selected in order to expose a test object (200) to a maximum field line density, the end faces (122, 132) in large test objects (200) at an angle of 0 ° are aligned collinear, with two further electrically coupled inductor bodies (110) for the purpose of a positive ven superimposition of the respective magnetic fields are set up opposite one another in antiparallel, the respective end faces (122, 132) of the two inductor bodies (110) pointing in the same direction at an angle of 0 ° being aligned collinear to one another.

Description

The invention relates to an inductor device for heat excitation of a test object by generating an eddy current inside an electrically conductive test object with an inductor body in the form of at least one U-profile, in which two opposing legs are connected to one another via a base element, each of the legs in the Area of its free end is enclosed by a coil body and the current flow through the relevant coil body takes place in such a way that the field lines present centrally between the coil bodies are superimposed in the same direction.

Inductor devices of the type mentioned at the beginning are used in the prior art in particular for a non-destructive examination of metallic test objects for the presence of cracks or other defects.

The known inductor devices, however, have the disadvantage that their sensitivity for recognizing, in particular, small and weakly formed fine flaws is still too low. Furthermore, by means of the inductor devices known in the prior art, it is not possible to examine test objects with a complicated shape, such as, for example, toothed wheels or hollow cylinders or hollow cuboids.

A device of the type mentioned is from the document CN 1 05 823 797 A known.

The pamphlet CN 1 725 478 A discloses a method and apparatus for monitoring a metal layer during chemical mechanical polishing.

From the pamphlet CN 1 09 324 085 A a non-destructive testing by means of an imaging, non-destructive induction thermal imaging testing system is known, which is based on a special yoke coil structure.

Methods and devices of induction thermography are also known from: WU, Yingshun et al .: Induction Thermography for Rail Nondestructive Testing under Speed Effect. In: IEEE Far East NTD New Technology & Application Forum (FENDT), 2018, pp 185-189.

The object of the invention is to create an inductor device by means of which a hitherto unachieved high concentration of magnetic field lines is made possible in a surface area of a test body that is easily visible to a camera and has individually predetermined dimensions.

For an inductor device of the type mentioned at the outset, this object is achieved according to the invention in that the relative orientation of the respective end faces ( 122 , 132 ) of the two free ends ( 121 , 131 ) of the opposite legs ( 120 , 130 ) Descriptive angle is selected depending on the size and shape of the test area in order to allow a test object ( 200 ) to a maximum field line density, whereby the end faces ( 122 , 132 ) for large test objects ( 200 ) are aligned collinearly to each other at an angle of 0 °, whereby two inductor bodies ( 110 ) are set up opposite one another in antiparallel to one another for the purpose of a positive superimposition of the respective magnetic fields, and the respective end faces ( 122 , 132 ) of the two inductor bodies ( 110 ) pointing in the same direction at an angle of 0 ° are collinear to one another, whereby the end faces ( 122 , 132 ) of the two inductor bodies ( 110 ) are arranged opposite one another, for the detection of cracks in the area of the surface and the lower surface as well as side surfaces of disk-shaped, cuboid or cylindrical test objects arranged at right angles to these surfaces ( 200 ), the sub-areas of which are to be examined successively.

Preferred embodiments of the invention are the subject matter of the subclaims, the elements of which act in the sense of a further improvement of the approach to the solution of the object on which the invention is based.

In the inductor device according to the invention, the combination of features of the characterizing part of claim 1 in conjunction with the features of the preamble enables a high field line concentration in the field of view of a camera for a test object with a wide range of different, individually specified dimensions.

In the inductor device according to the invention, two inductor bodies that are electrically coupled to one another are set up opposite one another in an antiparallel manner for the purpose of a positive superimposition of the respective magnetic fields, with the respective end faces of the two inductor bodies pointing in the same direction at an angle of 0 ° being aligned collinear to one another, wherein the end faces of the two inductor bodies face each other.

Such an arrangement is particularly suitable for the detection of cracks in the area of the surface and the lower surface as well as side surfaces of test objects that are arranged at right angles to these surfaces and have a highly individualized shape such as disk-shaped, cuboid, hollow cuboid cylindrical or hollow cylindrical test objects, for example gearwheels, in particular, are also suitable. In this embodiment, one or more mirrors can preferably be arranged to the side of a test object in order to capture the lateral areas of a test object with the aid of a camera arranged above or below the test object.

According to a first embodiment of the inductor device according to the invention, it is provided that the end faces, pointing in the same direction, are aligned collinear to one another at an angle of 0 °. Such an arrangement is particularly suitable for the detection of cracks in the area of the surface of comparatively large test objects, the partial areas of which are successively arranged in the free field of vision between the legs in question.

According to another preferred embodiment of the inductor device according to the invention, one or more mirrors are arranged to the side of a test object in order to also capture lateral areas of a test object with the aid of a single camera.

According to an alternative preferred embodiment of the invention, two anti-parallel arranged inductor bodies are provided, the respective end faces of which are oriented in the same direction at an angle of 0 ° collinear to one another, the opposing base elements of the two inductor bodies being joined together to form a one-piece overall base element. Such an arrangement is particularly suitable for a simultaneous detection of cracks in the area of the surface of toroidal, ring-shaped and also angular test objects, an evaluation of a plurality of individual surfaces of a test object also being possible.

In general, the inductor according to the invention is preferably cast in a hardenable plastic material for the purpose of thermal and electrical insulation or embedded in a housing made of an essentially solid plastic material in order to avoid a disruptive thermal interaction with the surface of the test object in the form of natural radiation and / or caused by side effects Avoid reflections.

Furthermore, the inductor according to the invention is preferably designed in its inner inductor core in such a way that the legs in question are connected to one another side by side or opposite one another via an inductor body, each of the legs being enclosed by a coil body and the current flow through the coil body in question in such a way that a rectified superimposition of the field lines present centrally between the bobbins is given.

The legs are in particular arranged in relation to the inductor base in question, so that in a central area of the inductor a recess that the camera can see directly or via a mirror on the surface of the magnetic flux, which is optimally aligned in this area, flows through it To create the test object.

Furthermore, an inductor body of complex shape can contain one or more inductor cores which are produced differentially or integrally or which are positively connected to one another or contain an inductor core which is produced integrally. An inductor core is formed in particular from a ferrimagnetic material with low hysteresis behavior.

According to a further important embodiment of the inductor device according to the invention, an inductor is rotatably mounted around the vertical longitudinal axis for the purpose of optimizing the finding of spatially differently oriented flaws and can be continuously rotated and locked in a predetermined position by means of a motor device. A relevant inductor is designed to generate a magnetic pulse at least in an initial position and in an end position of a rotation process.

Preferably, however, a relevant inductor is designed to generate a plurality of magnetic pulses during a rotation process.

An inductor core of the inductor device according to the invention is preferably formed from a ferrimagnetic material with low hysteresis behavior.

An induction generator for operating an inductor device according to the invention preferably supplies an alternating voltage in the frequency range of 8 kHz to 100 kHz, which enables the inductor to be supplied with power even by means of a flexible power cable of a comparatively large length of 5 m to 10 m.

• 1 eine erste bevorzugte Ausführungsform der erfindungsgemäßen Induktor-Vorrichtung in einer Ansicht von oben;
• 2 eine zweite bevorzugte Ausführungsform der erfindungsgemäßen Induktor-Vorrichtung in einer Ansicht von oben;
• 3 eine dritte bevorzugte Ausführungsform der erfindungsgemäßen Induktor-Vorrichtung in einer Ansicht von oben;
• 4 eine vierte bevorzugte Ausführungsform der erfindungsgemäßen Induktor-Vorrichtung in einer Ansicht von oben.

The inductor device according to the invention is explained below with reference to preferred embodiments which are shown in the figures of the drawing. It shows:

• 1 a first preferred embodiment of the inductor device according to the invention in a view from above;
• 2 a second preferred embodiment of the inductor device according to the invention in a view from above;
• 3 a third preferred embodiment of the inductor device according to the invention in a view from above;
• 4th a fourth preferred embodiment of the inductor device according to the invention in a view from above.

The ones in the 1 until 4th illustrated inductor devices according to the invention 100 are for a heat stimulation of a test object 200 by generating an eddy current inside an electrically conductive test object 200 with an inductor body 110 provided in the form of at least one U-profile, in which two opposing legs 120 , 130 via a base element 140 are connected to each other.

Each of the thighs 120 , 130 is in the area of its free end 121 , 131 from a bobbin 150 enclosed, the current flow through the respective coil formers 150 takes place in such a way that a rectified superimposition of the centrally between the bobbins 150 existing field lines is given.

On the relative orientation of the respective end faces 122 , 132 of the two free ends 121 , 131 of the opposite legs 120 , 130 Descriptive angle is selected depending on the size and shape of the test area around a test object 200 to expose a maximum field line density, the end faces 122 , 132 for small-area test objects 200 are aligned parallel to one another at an angle of 180 ° to one another, the end faces 122 , 132 for large test objects 200 are aligned collinearly to one another at an angle of 0 ° and for test objects 200 with surfaces measured in between are aligned at an angle between 180 ° and 0 ° to one another.

According to the in 1 The embodiment shown are the end faces 122 , 132 aligned parallel to one another at an angle of 180 ° to one another, whereby this embodiment is particularly suitable for detecting cracks in the area of predetermined sections of the lateral surface of rod-shaped test objects with small cross-sections 200 suitable is.

According to the in 2 The embodiment shown are the end faces 122 , 132 pointing in the same direction at an angle of 0 ° to one another collinearly, whereby this embodiment is particularly suitable for detecting cracks in the area of the surface of comparatively large test objects 200 is suitable whose sub-areas successively in the free field of vision between the legs in question 120 , 130 to be ordered.

According to the in 3 The illustrated embodiment according to the invention are two inductor bodies that are electrically coupled to one another 110 for the purpose of a positive superimposition of the respective magnetic fields set up opposite one another in antiparallel, the respective end faces 122 , 132 of the two inductor bodies 110 pointing in the same direction at an angle of 0 ° to one another are aligned collinear, the end faces 122 , 132 of the two inductor bodies 110 face. This embodiment is in particular for detecting cracks in the area of the surface and the lower surface as well as side surfaces of disk-shaped, cuboid, or cylindrical test objects arranged at right angles to these surfaces 200 , for example, but also suitable for gears, the sub-areas of which are successively subjected to a test.

At the in 3 The preferred embodiment shown are on the side of a test object 200 two mirrors 160 , 161 arranged to also lateral areas of a test object 200 with the help of a single camera 170 capture.

According to a further preferred embodiment, there are two inductor bodies set up anti-parallel 110 provided, their respective end faces 122 , 132 pointing in the same direction at an angle of 0 ° to one another are collinearly aligned, the opposing base elements 140 of the two inductor bodies 110 are joined together to form a one-piece overall base element, whereby this embodiment is particularly suitable for detecting cracks in the area of the surface of a plurality of test objects to be examined at the same time 200 suitable is. This embodiment is also particularly suitable for examining the upper and lower surfaces and, if applicable, the visible side surfaces of toroidal or ring-shaped test objects 200 suitable.

For the purpose of thermal and electrical insulation, each inductor is cast in a hardenable plastic material in order to avoid a disruptive thermal interaction with the surface of the test object caused by side effects 200 in the form of natural radiation and / or reflections.

Furthermore, each inductor is designed in its inner inductor core in such a way that the relevant limbs 120 , 130 next to one another or opposite one another via an inductor body 110 are interconnected, each of the legs 120 , 130 from a bobbin 150 is enclosed and wherein the current flow through the respective coil formers 150 takes place in such a way that a rectified superimposition of the centrally between the bobbins 150 existing field lines is given.

The thigh 120 , 130 are arranged in relation to the inductor base in question in such a way that one for the camera in a central area of the inductor 170 directly or via mirror 160 , 161 Visible cutout on the surface of the test object through which a strong magnetic flux flows in this area, which is optimally aligned for heating up the defect 200 is created.

The one in the 3 The illustrated complex-shaped inductor contains two inductor cores which are manufactured integrally from a ferrimagnetic material with low hysteresis behavior. The ones in the 1 , 2 and 4th The complex-shaped inductors shown each contain an inductor core which is manufactured integrally from a ferrimagnetic material with low hysteresis behavior.

The ones in the 2 and 3 For the purpose of optimizing the finding of spatially differently oriented flaws, the illustrated inductors are rotatably mounted about a respective vertical longitudinal axis and can be continuously rotated and locked in a predetermined position by means of a motor-driven rotation device.

The one in the 1 and 4th shown inductors or relevant test objects 200 are for the purpose of reducing in the area of the end faces 122 , 132 the bobbin 150 Existing test area sub-areas with reduced sensitivity or due to the relevant end faces 122 , 132 even covered partial areas of the jacket surface are rotatably mounted about a respective central longitudinal axis and can be continuously rotated and locked in a predetermined position by means of a motor-driven rotation device.

Each inductor core is made of a ferrimagnetic material with low hysteresis behavior.

A relevant inductor is designed to generate a plurality of magnetic pulses during a rotation process.

An induction generator for operating an inductor device according to the invention 100 supplies an alternating voltage in the frequency range of 50 kHz, which enables the inductor to be supplied with power even by means of a flexible power cable of a comparatively long length of 10 m.

The exemplary embodiment of the invention explained above only serves the purpose of a better understanding of the teaching according to the invention given by the claims, which as such is not restricted by the exemplary embodiment.

List of reference symbols

100

Inductor device

110

Inductor body

120, 130

leg

121, 131

free end of a leg

122, 132

End face of a leg

140

Base element

150

Bobbin

160, 161

mirrors

170

camera

200

Test object

Claims (8)

Inductor device (100) for heat excitation of a test object (200) by generating an eddy current inside an electrically conductive test object (200) with an inductor body (110) in the form of at least one U-profile, in which two opposing legs (120, 130 ) are connected to one another via a base element (140), each of the legs (120, 130) being enclosed in the region of its free end (121, 131) by a coil former (150) and the current flow through the relevant coil former (150) in this way that the field lines present centrally between the coil bodies (150) are superimposed in the same direction, characterized in that - the relative orientation of the respective end faces (122, 132) of the two free ends (121, 131) of the respective opposing legs ( 120, 130) descriptive angle depending on the size and shape of the test area is selected to a test object (200) a maximum Feldli The end faces (122, 132) of large test objects (200) are collinearly aligned at an angle of 0 ° to one another, two electrically coupled inductor bodies (110) facing one another for the purpose of a positive superimposition of the respective magnetic fields are set up antiparallel, and wherein the respective end faces (122, 132) of the two inductor bodies (110) pointing in the same direction are aligned collinearly at an angle of 0 ° to one another, wherein - the end faces (122, 132) of the two inductor bodies (110) are arranged opposite one another, for the detection of cracks in the area of the surface and the lower surface as well as side surfaces of disk-shaped, cuboid or cylindrical test objects (200) arranged at right angles to these surfaces, whose sub-areas successively one To be examined. Inductor device (100) Claim 1 , characterized in that the end faces (122, 132) pointing in the same direction are collinearly aligned at an angle of 0 ° to one another, for the detection of cracks in the area of the surface of comparatively large test objects (200), the partial areas of which are successively in the free field of view between the legs (120, 130) in question are arranged. Inductor device (100) according to one of the preceding claims, characterized in that one or more mirrors (160, 161) are arranged to the side of a test object (200) in order to also detect lateral areas of a test object (200) with the aid of a single camera (170 ) capture. Inductor device (100) Claim 1 , characterized in that two anti-parallel set up inductor bodies (110) are provided, the respective end faces (122, 132) pointing in the same direction at an angle of 0 ° to each other are aligned collinear, the opposing base elements (140) of the two inductor bodies (110) combine to form a one-piece overall base element for the detection of cracks in the area of the surface of a plurality of test objects to be examined simultaneously (200) or the upper and lower surface and the visible side surfaces of toroidal or ring-shaped test objects (200). Device (100) according to one of the Claims 1 until 4th , characterized in that the inductor is embedded in a housing made of a substantially solid plastic material for the purpose of thermal and electrical insulation in order to avoid disruptive thermal interaction with the surface of the test object (200) caused by side effects in the form of natural radiation and / or reflections to avoid. Device (100) according to one of the Claims 1 until 4th , characterized in that the inductor is cast in a curable plastic material for thermal and electrical insulation in order to avoid a disruptive thermal interaction with the surface of the test object (200) in the form of natural radiation and / or reflections caused by side effects. Device (100) according to one of the preceding claims, characterized in that the inductor is designed in its inner inductor core in such a way that relevant legs (120, 130) are connected to one another side by side or opposite one another via an inductor body (110), each of the legs (120, 130) is enclosed by a coil body (150) and the current flow through the relevant coil body (150) takes place in such a way that the field lines present centrally between the coil bodies (150) are superimposed in the same direction. Device (100) according to Claim 7 , characterized in that the legs (120, 130) are arranged in relation to the respective inductor base element in order to be visible for the camera (170) directly or via one or more mirrors (160, 161) in a central area of the inductor To create a recess on the surface of the test object (200) through which a strong magnetic flux flows in this area, which is optimally aligned for heating up the defect.

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