Inductive sensor device for determining a longitudinal position of a moveable object along a sensitive axis of the sensor device and method for operating a sensor device of this kind

Patent metadata

Field	Value
Publication number	US-2022196438-A1
Application number	US-202117524028-A
Country	US
Kind code	A1
Filing date	Nov 11, 2021
Priority date	Dec 18, 2020
Publication date	Jun 23, 2022
Grant date	—

Abstract

An inductive sensor device has a coil arrangement and sensor electronics for determining a longitudinal position of an at least partially electrically conductive and/or magnetically polarizable object moveable at a distance from a device end face along a device sensitive axis. The arrangement has a substantially planar exciting coil for producing an alternating magnetic field for inducing eddy currents and/or magnetic polarization in the object and a first substantially planar receiving coil substantially parallel to and overlapping the exciting coil. The coils are substantially parallel to the end face. The sensor electronics determine at least one parameter of an exciting coil electrical signal, which is variable owing to an inductive backward effect of the object, at least one parameter of a voltage inducible in the at least first receiving coil based on this effect, and the longitudinal position from the determined signal parameter and the determined voltage parameter.

First claim

What is claimed is:

1 . An inductive sensor device ( 10 ) for determining a longitudinal position (P) of an object ( 11 ) which is moveable at a distance from an end face ( 12 ) of the sensor device ( 10 ) and which is at least partially electrically conductive and/or magnetically polarizable, along a sensitive axis (S 1 ) of the sensor device ( 10 ),
wherein the sensor device ( 10 ) has a coil arrangement ( 14 ) and sensor electronics ( 30 ), wherein the coil arrangement ( 14 ) has a substantially planar exciting coil ( 16 ), by means of which an alternating magnetic field is producible for inducing eddy currents and/or magnetic polarization in the object ( 11 ), and a first substantially planar receiving coil ( 18 ; 18 a - 18 b ), which is arranged substantially parallel to and overlapping the exciting coil ( 16 ), wherein the exciting coil ( 16 ) and the first receiving coil ( 18 ; 18 a - 18 b ) are arranged substantially parallel to the end face ( 12 ) of the sensor device ( 10 ), and wherein the sensor electronics ( 30 ) are configured to determine at least one parameter (DSS) of an electrical signal of the exciting coil ( 16 ), which is variable owing to an inductive backward effect of the object ( 11 ), and at least one parameter (PSS) of a voltage inducible in the at least first receiving coil ( 18 ; 18 a - 18 b ) owing to the inductive backward effect of the object ( 11 ) and to determine the longitudinal position (P) from the determined parameter (DSS) of the electrical signal of the exciting coil ( 16 ) and the determined parameter (PSS) of the inducible voltage in the first receiving coil ( 18 ; 18 a - 18 b ).

2 . A sensor device according to claim 1 , wherein the sensor electronics ( 30 ) are configured to determine a vertical distance (D) of the object ( 11 ) between the end face ( 11 ) of the sensor device ( 10 ) and the object ( 11 ) from the at least one parameter determined (DSS) of the electrical signal of the exciting coil ( 16 ) and the at least one parameter determined (PSS) of the inducible voltage of the receiving coil ( 18 ; 18 a - 18 b ).

3 . The sensor device according to claim 1 , wherein the first receiving coil ( 18 ; 18 a - 18 b ) is of anti-symmetrically polarizable configuration along the sensitive axis (S 1 ).

4 . The sensor device ( 10 ) according to claim 1 ,
wherein the coil arrangement ( 14 ) has a second substantially planar receiving coil ( 18 b ), which is arranged substantially parallel to and overlapping the exciting coil ( 16 ), and wherein the second receiving coil ( 18 b ) overlaps the first receiving coil ( 18 a ) in the end regions thereof and is connected electrically in series with the first receiving coil ( 18 a ).

5 . The sensor device ( 10 ) according to claim 1 ,
wherein the coil arrangement ( 14 ) has at least a third substantially planar receiving coil ( 68 ), which is arranged substantially parallel to and overlapping the exciting coil ( 16 ) and which defines an additional sensitive axis (S 2 ) of the sensor device ( 10 ), which extends substantially perpendicular to or in the sensitive axis (S 1 ) of the first receiving coil ( 18 ; 18 a , 18 b ), and wherein the sensor electronics ( 30 ) are configured to determine at least one parameter (LSS) of a voltage inducible in the third receiving coil ( 68 ) due to the inductive backward effect of the object ( 11 ) and for determining the lateral position (L) of the object ( 11 ) along the additional sensitive axis (S 2 ) from the determined at least one parameter (DSS) of an electrical signal of the exciting coil ( 16 ) and the determined at least one parameter (LSS) of the inducible voltage of the third receiving coil ( 68 ).

6 . The sensor device ( 10 ) according to claim 5 ,
wherein the coil arrangement ( 14 ) has a fourth substantially planar receiving coil, which is arranged substantially parallel to and overlapping the exciting coil ( 16 ), and wherein the fourth receiving coil overlaps the third receiving coil ( 68 ) in the end regions thereof and is connected electrically in series with the third receiving coil ( 68 ).

7 . The sensor device ( 10 ) according to claim 1 , wherein the exciting coil ( 16 ), the first receiving coil ( 18 ; 18 a ), the second receiving coil ( 18 b ), the third receiving coil ( 68 ) and/or the fourth receiving coil are arranged on or in one or more layers ( 50 , 52 , 60 , 62 ) of a printed-circuit board ( 38 ).

8 . The sensor device ( 10 ) according to claim 1 , wherein the exciting coil ( 16 ), the first receiving coil ( 18 ; 18 a ), the second receiving coil ( 18 b ), the third receiving coil ( 68 ) and/or the fourth receiving coil are made by a wire-wrapping technique.

9 . The sensor device ( 10 ) according to claim 7 , wherein windings ( 56 , 58 ) of coil segments ( 21 a , 21 b ; 40 a , 40 b ) of the receiving coil ( 18 ; 18 a - 18 b ; 68 ) are oppositely directed, viewed along their respective sensitive axis (S 1 , S 2 ).

10 . The sensor device ( 10 ) according to claim 8 , wherein the receiving coil ( 18 ; 18 a - 18 b ; 68 ), viewed along their respective sensitive axis (S 1 , S 2 ), has substantially centrally crossed windings ( 20 a , 20 b ).

11 . The sensor device ( 10 ) according to claim 1 , wherein the sensor device ( 10 ) further comprises a first electrically conductive shielding element ( 22 a ), which surrounds the coil arrangement ( 14 ) laterally, in particular completely.

12 . The sensor device ( 10 ) according to claim 1 , wherein the sensor device ( 10 ) further comprises a second electrically conductive, planar shielding element ( 22 b ), which is arranged on a side of the coil arrangement ( 14 ) that is turned away from the object ( 11 ).

13 . The sensor device ( 10 ) according to claim 11 , wherein, viewed in a direction perpendicular to the sensitive axis (S 1 , S 2 ), symmetrically and on either side of the coil arrangement ( 14 ), in each case a coil-free region ( 66 ) is provided adjacent to the first shielding element ( 22 a ), whose width (d) is at least 10% of a width (b) of an opening ( 64 ) of the first shielding element ( 22 a ).

14 . The sensor device ( 10 ) according to claim 1 , wherein the exciting coil ( 16 ) is excitable substantially with a periodic, in particular a substantially sinusoidal, current or a periodic, in particular a substantially sinusoidal, voltage.

15 . The sensor device ( 10 ) according to claim 1 , wherein the exciting coil ( 16 ) is a part of an oscillating circuit ( 80 ) of the sensor electronics ( 30 ).

16 . The sensor device ( 10 ) according to claim 1 , wherein the exciting coil ( 16 ), as an inductive element of an LC circuit, is a part of a self-oscillating LC oscillating circuit ( 80 ).

17 . The sensor device ( 10 ) according to claim 1 , wherein the at least one parameter (DSS) determined from the electrical signal of the exciting coil is a frequency (f OSC ), or an amplitude (U D ).

18 . The sensor device ( 10 ) according to claim 1 , wherein the sensor electronics ( 30 ) are configured for determining a proximity signal (S N ) from the changes of the determinable parameter of the electrical signal of the exciting coil ( 16 ) caused by the presence of the object ( 11 ), which is indicative of the change of the at least one parameter (DSS) caused by the presence of the object ( 11 ).

19 . The sensor device ( 10 ) according to claim 1 , wherein the sensor electronics ( 30 ) are configured for determining at le

Assignees

• Balluff Gmbh

Inventors

• Kantor Zoltan
• Szabó Attila

Classifications

• G01D5/20 Primary

  by varying inductance, e.g. by a movable armature · CPC title

• G01D5/2006 Primary

  by influencing the self-induction of one or more coils (G01D5/22 takes precedence) · CPC title

• G01D5/204

  by influencing the mutual induction between two or more coils (G01D5/22 takes precedence) · CPC title

• G01D5/2291 Primary

  Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils · CPC title

• H03K17/954

  controlled by an oscillatory signal · CPC title