Inductive displacement sensors

A transducer for an inductive displacement sensor, the transducer comprising:

• a primary winding producing a uniform magnetic excitation in a first circular annular strip of the transducer identical to a first circular annular strip of a target, facing the first circular annular strip of the target;
• a first set of at least two secondary windings each comprising N first turns of the same winding direction or 2N first turns of alternating winding directions, regularly distributed along a zone having a dimension Dtot in a direction, each first turn having a dimension in said direction approximately equal to Dtot/2N of the first circular annular strip of the transducer, and the N or 2N first turns of each winding being regularly distributed along the first circular annular strip of the transducer;
• and
• a second set of at least two secondary windings each comprising N+r second turns of the same winding direction or 2(N+r) second turns of alternating winding directions, regularly distributed along said zone, each second turn having a dimension in said direction approximately equal to Dtot/2(N+r) of a second circular annular strip of the transducer, identical to a second circular annular strip of the target and facing the second circular annular strip of the target, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N−1,
• wherein first and second turns overlap at least partially.

An inductive displacement sensor comprising:

• a target, the target comprising
• a plurality of separated conductive patterns distributed along a zone having a dimension Dtot in a direction of a first circular annular strip or wide strip of the target, said patterns being defined by an overlay of at least
• a first set of elementary periodic patterns having a period approximately equal to Dtot/N, including N first elementary conductive patterns of a dimension approximately equal to Dtot/2N in said direction, regularly distributed along the first circular annular strip of the target, each of the first elementary periodic patterns having the shape of a sector of the first circular annular strip of the target, and
• a second set of elementary periodic patterns having a period approximately equal to Dtot/(N+r), including N+r second elementary patterns of a dimension approximately equal to Dtot/2(N+r) in said direction, regularly distributed along a second circular annular strip or narrow strip of the target, concentric with the first circular annular strip and included in the first circular annular strip, each of the second elementary patterns having the shape of an annular sector of the second circular annular strip of the target, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N−1;
• and
• a transducer comprising
• a primary winding producing a uniform magnetic excitation in a first circular annular strip of the transducer identical to the first circular annular strip of the target, facing the first circular annular strip of the target,
• a first set of at least two secondary windings each comprising N first turns of the same winding direction or 2N first turns of alternating winding directions, regularly distributed along the zone having the dimension Dtot in the direction of the first circular annular strip or the wide strip of the target, each first turn having a dimension in said direction approximately equal to Dtot/2N of the first circular annular strip of the transducer, and the N or 2N first turns of each winding being regularly distributed along the first circular annular strip of the transducer, and
• a second set of at least two secondary windings each comprising N+r second turns of the same winding direction or 2(N+r) second turns of alternating winding directions, regularly distributed along said zone, each second turn having a dimension in said direction approximately equal to Dtot/2(N+r) of a second circular annular strip of the transducer, identical to the second circular annular strip of the target and facing the second circular annular strip of the target, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N−1,
• wherein first and second turns overlap at least partially, and
• wherein first and second elementary conductive patterns overlap at least partially.