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1. (WO2017194374) SENSOR ASSEMBLY FOR DETECTING A DISPLACEMENT IN A CONTACTLESS MANNER, AND METHOD FOR DETERMINING A RELATIVE POSITION

Pub. No.:    WO/2017/194374    International Application No.:    PCT/EP2017/060600
Publication Date: Fri Nov 17 00:59:59 CET 2017 International Filing Date: Fri May 05 01:59:59 CEST 2017
IPC: G01D 5/20
Applicants: ROBERT BOSCH GMBH
Inventors: HERRMANN, Ingo
UTERMOEHLEN, Fabian
Title: SENSOR ASSEMBLY FOR DETECTING A DISPLACEMENT IN A CONTACTLESS MANNER, AND METHOD FOR DETERMINING A RELATIVE POSITION
Abstract:
The invention relates to a sensor assembly (1) for detecting a displacement in a contactless manner, comprising a target (10), which has a measurement value transmitter (14) that moves along a measurement path (M) and comprises at least one electrically conductive measurement track (MS1, MS2, MS3, MS4), and an eddy current sensor (20) with a measurement value sensor (22) which comprises at least two detection coils (A, B, C, D). The measurement value sensor (22) is arranged at a distance from the measurement value transmitter (14) and in a relatively movable manner along the at least one electrically conductive measurement track (MS1, MS2, MS3, MS4), and the measurement value sensor at least partly covers the measurement track. At least one of the detection coils (A, B, C, D) acts as a measurement coil, the measurement signal of which is evaluated by an evaluating and control unit (5) in order to detect a displacement. The invention also relates to a method for determining the position of a sensor (20) relative to a target (10) of a sensor assembly (1) for detecting a displacement in a contactless manner. The measurement value transmitter (14) has at least one electrically conductive correction track (KS11, KS12, KS21, KS22, KS31, KS32, KS41, KS42) which is arranged together with the at least one measurement track (MS1, MS2, MS3, MS4) within a common geometry. First regions (x1) with at least one measurement track (MS1, MS2, MS3, MS4) and second regions (x2) with at least one correction track (KS11, KS12, KS21, KS22, KS31) alternate periodically along the measurement path (M). At least one of the detection coils (A, B, C, D) acts as a correction coil, the measurement signal of which is evaluated by the evaluating and control unit (5) in order to correct the displacement detection. The action of the individual detection coils (A, B, C, D) as measurement coils or as correction coils varies along the measurement path (M), wherein the evaluating and control unit (5) assigns a detection coil (A, B, C, D) the measurement coil action if the corresponding detection coil (A, B, C, D) is positioned over a first region (x1) or the correction coil action if the corresponding detection coil (A, B, C, D) is positioned over a second region (x2).