Device and method for sensing torques, torsional natural frequencies, and/or torsional oscillations without contact

Patent metadata

Field	Value
Publication number	US-10845257-B2
Application number	US-201615770791-A
Country	US
Kind code	B2
Filing date	Nov 2, 2016
Priority date	Nov 3, 2015
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

The invention relates to a device ( 14 ) and to a method for the contactless detection of a torque of a shaft ( 10 ) and/or torsional natural frequencies and/or torsional oscillations. The shaft ( 10 ) contains a ferromagnetic material. A measurement head ( 16 ) facing toward a shaft wall ( 12 ) comprises an excitation coil ( 22 ) which couples a magnetic field into the shaft ( 10 ). The measurement head ( 16 ) furthermore contains a number of measurement coils ( 24, 26, 28, 30 ), which measure the magnetic field emerging from the shaft ( 10 ).

First claim

The invention claimed is:

1. A device for the contactless detection of a torque of a shaft and/or of torsional natural frequencies and/or of torsional oscillations, the shaft containing a ferromagnetic material, wherein a measurement head facing toward a shaft wall of the shaft comprises an excitation coil which couples a magnetic field into the shaft, and the measurement head contains a number of measurement coils, which measure a magnetic field emerging from the shaft the measurement head is made of PEEK, the measurement head is arranged at a distance from the shaft wall, the distance lies between 0.5 mm and 1 mm.

2. The device according to claim 1 , wherein the measurement coils are arranged symmetrically with respect to one another.

3. The device according to claim 2 , wherein the measurement coils are arranged at an angle of 45° relative to the main axes of the shaft.

4. The device according to claim 1 , wherein an excitation frequency of the excitation coil lies between 50 kHz and 150 kHz.

5. The device according to claim 4 , wherein the excitation frequency of the excitation coil lies between 75 kHz and 125 kHz.

6. The device according to claim 5 , wherein the excitation frequency of the excitation coil is about 100 kHz.

7. The device according to claim 1 , wherein a distance of all measurement coils contained in the measurement head relative to the excitation coil is equal.

8. A method for the contactless detection of torques of a shaft and/or of torsional natural frequencies and/or of torsional oscillations comprising use of a device according to claim 1 , wherein
a) an excitation coil of the device couples a magnetic field into the shaft,
b) a number of measurement coils measure a magnetic field emerging from the shaft,
c) a sum of all voltages at the measurement coils is measured and
d) the device for the detection of torques and/or torsional natural frequencies and/or torsional oscillations is calibrated by stationary measurements at two known load points.

9. The method according to claim 8 , wherein the direction of a detected torque is determined from the sign of the voltage differences between the number of measurement coils.

10. The method according to claim 8 , wherein surface stresses, proportional to the torque, in a shaft wall of the shaft are measured.

11. The method according to claim 8 , wherein the frequency and strength of the magnetic field coupled in by the excitation coil allow a linear measurement signal over a frequency range of from 80 kHz to 120 kHz.

12. The method according to claim 8 , wherein an electric current of between 4 mA and 20 mA is generated as the measurement signal.

13. The method according to claim 8 , wherein the excitation coil is operated with a supply voltage of 24 volts.

14. The device according to claim 1 , wherein the measurement head is arranged at a distance from the shaft wall of 0.75 mm.

Assignees

• Basf Se

Inventors

• Stephan Oskar
• Schuhmann Roland
• Catternan Tom

Classifications

• G01L3/102

  involving magnetostrictive means (magnetostrictive sensors H10N35/101) · CPC title

• G01L3/105

  involving inductive means (G01L3/102, G01L3/104 take precedence) · CPC title

• G01L1/127

  by using inductive means (G01L1/122, G01L1/125 take precedence) · CPC title

• G01L1/125 Primary

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

• G01L3/103

  Details about the magnetic material used · CPC title