Sensor arrangement and method for determining the mechanical surface stresses and/or the microstructure state

Patent metadata

Field	Value
Publication number	US-9909938-B2
Application number	US-201414911120-A
Country	US
Kind code	B2
Filing date	Aug 25, 2014
Priority date	Sep 3, 2013
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A sensor assembly for detecting surfaces stresses and/or the microstructure state of a ferromagnetic workpiece, wherein at least one first base coil system having a first directional sensitivity is provided, at least one second base coil system having a second directional sensitivity is provided, and at least one third base coil system having a third direction and a third directional sensitivity is provided, and wherein at least the first base coil system and the second base coil system form a first differential angle and the second base coil system and the third base coil system form a second differential angle, and wherein the first base coil system, the second base coil system, and the third base coil system are arranged such that the mechanical surface stresses of the workpiece can be at least partially determined. A method for determining the mechanical surface stresses is also provided.

First claim

The invention claimed is:

1. A sensor arrangement for detecting at least one of the surface stresses and the microstructure state of a ferromagnetic workpiece, the sensor arrangement comprising:
a first basic coil system, a second basic coil system, and a third basic coil system, wherein each of the first basic coil system, second basic coil system, and third basic coil system comprise at least one excitation coil and at least one receiver coil;
wherein the first basic coil system has a first direction and a first directional sensitivity, the second basic coil system has a second direction and a second directional sensitivity, and the third basic coil system has a third direction and a third directional sensitivity;
the first basic coil system and the second basic coil system forming a first differential angle and the second basic coil system and the third basic coil system forming a second differential angle;
the first basic coil system being arranged outside the second directional sensitivity and the third directional sensitivity, the second basic coil system being arranged outside the first directional sensitivity and the third directional sensitivity, and the third basic coil system being arranged outside the first directional sensitivity and the second directional sensitivity, with the result that the mechanical surface stresses of the ferromagnetic workpiece can be at least partially determined using vector components based upon the directional sensitivity and direction of the first basic coil system, the second basic coil system and the third basic coil system and the first differential angle and second differential angle.

2. The sensor arrangement as claimed in claim 1 , wherein the excitation coil and the receiver coil have a coil core with a coil core diameter, and the directional sensitivity is given by the ratio of the distance between the two coil cores and/or by the ratio of the two coil core diameters.

3. The sensor arrangement as claimed in claim 1 , wherein at least one of the first basic coil system and the second basic coil system and the third basic coil system comprise(s) an excitation coil and a receiver coil which are arranged on a U ferrite core.

4. The sensor arrangement as claimed in claim 1 , wherein at least one of the first basic coil system and the second basic coil system and the third basic coil system comprise(s) an excitation coil and a first receiver coil and a second receiver coil which are arranged on a U ferrite core, the excitation coil being arranged between, in particular centrally between, the first receiver coil and the second receiver coil.

5. The sensor arrangement as claimed in claim 1 , wherein at least one of the first basic coil system and the second basic coil system and the third basic coil system comprise(s) an excitation coil and a first receiver coil and a second receiver coil which are arranged on an E ferrite core, the excitation coil being arranged, in particular centrally in the center, between the first receiver coil and the second receiver coil.

6. The sensor arrangement as claimed in claim 1 wherein at least two excitation coils of the first, second, and third basic coil systems have a series circuit.

7. The sensor arrangement of claim 1 , further comprising a fourth basic coil system having an excitation coil and a receiver coil;
the fourth basic coil system having a fourth receiver coil;
wherein the first basic coil system, second basic coil system, third basic coil system, and fourth basic coil system all share a single excitation coil;
further wherein, the single excitation coil and the first, second, third, and fourth receiver coils are arranged on a common ferrite core.

8. The sensor arrangement as claimed in claim 7 , wherein the four receiver coils are at the same distance from the single excitation coil, and adjacent receiver coils are each arranged at the same distance from one another.

9. The sensor arrangement of claim 1 , wherein:
further wherein the first basic coil system, second basic coil system, and third basic coil system all share a single excitation coil;
further wherein the first, second, and third basic coil systems, including the shared single excitation coil, are arranged on a common ferrite core.

10. The sensor arrangement as claimed in claim 9 , wherein the three receiver coils are at the same distance from the shared single excitation coil, and adjacent receiver coils are each arranged at the same distance from one another.

11. The sensor arrangement of claim 1 , further comprising:
a fourth, fifth, and sixth basic coil system, each of the fourth, fifth, and sixth basic coil systems having an excitation coil and a receiver coil;
wherein the first basic coil system, second basic coil system, third basic coil system, fourth basic coil system, fifth basic coil system, and sixth basic coil system share a single excitation coil;
further wherein the first, second, third, fourth, fifth, and sixth basic coil systems, including the shared single excitation coil, are arranged on a common ferrite core.

12. The sensor arrangement as claimed in claim 11 , wherein the six receiver coils are at the same distance from the shared single excitation coil, and adjacent receiver coils are each arranged at the same distance from one another.

13. The sensor arrangement as claimed in claim 1 , wherein the first differential angle is equal to the second differential angle and is, in particular, 45 degrees.

14. The sensor arrangement as claimed in claim 1 , wherein the first differential angle and the second differential angle are 60 degrees.

15. The sensor arrangement as claimed in claim 1 , wherein the first differential angle and the second differential angle are 120 degrees.

16. The sensor arrangement as claimed in claim 1 , wherein at least one coil axis is included, the sensor arrangement being arranged with respect to a surface of the workpiece in such a manner that an orthogonal orientation of the coil axis with respect to the surface of the workpiece is achieved, and the sensor arrangement being at a nominal distance from this surface of the ferromagnetic workpiece, at least the first basic coil system and the second basic coil system and the third basic coil system being at a distance of at most 20% of the nominal distance from one another.

17. The sensor arrangement as claimed in claim 1 , wherein at least the first basic coil system and the second basic coil system and the third basic coil system are arranged on a suitable holding device.

18. A method for determining the mechanical surface stresses and/or the microstructure state of a ferromagnetic workpiece by means of the following steps:
determining at least three independent measured values by a sensor arrangement as claimed in claim 1 , wherein the three independent measured values are provided by the first, second, and third basic coil systems;
determining the direction-dependent permeability at a particular measuring point by a computing algorithm.

19. The method as claimed in claim 18 , wherein
a plurality of measuring points of the workpiece are determined and it is possible to determine a direction-dependent permeability therefrom, and the internal stress tensor is therefore mapped.

20. A sensor arrangement for detecting at least one of the surface stresses and the microstructure state of a ferromagnetic workpiece, the sensor arrangement comprising:
a composite excitation coil;
a first composite receiver coil;
a second composite receiver coil;
a third composite receiv

Assignees

• Siemens Ag

Inventors

• Brummel Hans Gerd
• Pfeifer Uwe

Classifications

• G01N27/902

  by moving the sensors · CPC title

• G01M5/0041

  by determining deflection or stress · CPC title

• G01L1/125 Primary

  by using magnetostrictive means (magnetostrictive sensors H10N35/101) · CPC title

• G01N27/904

  with two or more sensors · CPC title