US-12624939-B2 - Sensing element for an inductive angle measuring device

US12624939B2US 12624939 B2US12624939 B2US 12624939B2US-12624939-B2

Abstract

A sensing element for an inductive angle measuring device includes a first, a second, a third, and a fourth receiving conductive path. The second receiving conductive path extends over a second arc length, and the fourth receiving conductive path extends over a fourth arc length. The course of the first receiving conductive path and the third receiving conductive path is periodic along a first circular line. The course of the second receiving conductive path and the fourth receiving conductive path is periodic along a second circular line. The second receiving conductive path and the fourth receiving conductive path are arranged such that there is a first gap with a first gap length and a second gap with a second gap length between them in the circumferential direction. The first gap length and the second gap length are of different sizes, or the second arc length and the fourth arc length are of different sizes.

Inventors

Christoph Heinemann
Martin Heumann

Assignees

DR. JOHANNES HEIDENHAIN GMBH

Dates

Publication Date: 20260512
Application Date: 20240209
Priority Date: 20230223

Claims (20)

1 . A sensing element for an inductive angle measuring device, comprising: a first detector unit including a first receiving conductive path; a second detector unit including a second receiving conductive path that extends over a second arc length; a third detector unit including a third receiving conductor path; and a fourth detector unit including a fourth receiving conductor path that extends over a fourth arc length; wherein a course of the first receiving conductive path and of the third receiving conductive path is periodic along a first circular line having a first radius; wherein a course of the second receiving conductive path and of the fourth receiving conductive path is periodic along a second circular line having a second radius; wherein a first gap having a first gap length and a second gap having a second gap length are arranged between the second receiving conductive path and the fourth receiving conductive path in a circumferential direction; wherein the first radius and the second radius are different; and wherein the first gap length and the second gap length are of different sizes or the second arc length and the fourth arc length are of different sizes.
2 . The sensing element according to claim 1 , wherein each of the second receiving conductive path and the fourth receiving conductive path has a periodic course with a constant second period length, the first gap length is a first multiple of the second period length, the second gap length is a second multiple of the second period length, the following relationships being satisfied: β ⁢ 24 = m · λ ⁢ 2 and γ ⁢ 24 = n · λ ⁢ 2 , β24 representing the first gap length, γ24 representing the second gap length, λ2 representing the second period length, m representing the first multiple, n representing the second multiple, m and n being natural numbers greater than zero.
3 . The sensing element according to claim 1 , wherein the course of each of the second receiving conductive path and the fourth receiving conductive path is periodic with a constant second period length, the second period length being a second divisor of 360°.
4 . The sensing element according to claim 3 , wherein the second divisor is an odd number.
5 . The sensing element according claim 1 , wherein each of the second receiving conductive path and the fourth receiving conductive path has a periodic course with a constant second period length, the second arc length is a first multiple of the second period length, the fourth arc length is a second multiple of the second period length, the following relationships being satisfied: α2 = p · λ ⁢ 2 and α ⁢ 4 = q · λ ⁢ 2 , α2 representing the second arc length, α4 representing the fourth arc length, λ2 representing the second period length, p representing the first multiple, q representing the second multiple, p and q being natural numbers greater than zero.
6 . The sensing element according to claim 1 , wherein a third gap having a third gap length and a fourth gap having a fourth gap length are arranged between the first receiving conductive path and the third receiving conductive path in the circumferential direction.
7 . The sensing element according to claim 6 , wherein the third gap length and the fourth gap length are equal.
8 . The sensing element according to claim 6 , wherein the first receiving conductive path extends over a first arc length, the third receiving conductive path extends over a third arc length, and the first arc length and the third arc length are equal.
9 . The sensing element according to claim 1 , wherein the course of each of the first receiving conductive path and the third receiving conductive path is periodic having a constant first period length that is a first divisor of 360°.
10 . The sensing element according to claim 9 , wherein the first divisor is an even number.
11 . The sensing element according to claim 9 , wherein the course of each of the second receiving conductive path and the fourth receiving conductive path is periodic a constant second period length, the second period length being a second divisor of 360°.
12 . The sensing element according to claim 11 , wherein the first divisor is an even number, and the second divisor is an odd number.
13 . The sensing element according to claim 1 , wherein the first gap length is smaller than the second gap length, the course of the second receiving conductive path has a first amplitude within a first section and a second amplitude within a second section, the first section extending over a first angle starting from an end of the second receiving conductive path adjacent to the first gap, the second section extending over a second angle starting from another end of the second receiving conductive path adjacent to the second gap, each of the first angle and the second angle being less than or equal to half the second arc length, the first amplitude being smaller than the second amplitude.
14 . The sensing element according to claim 13 , wherein the course of the fourth receiving conductor path has a third amplitude within a third section and a fourth amplitude within a fourth section, the third section extending over a third angle starting from an end of the fourth receiving conductive path adjacent to the first gap, the fourth section extending over a fourth angle starting from another end of the fourth receiving conductive path adjacent to the second gap, each of the third angle and the fourth angle being less than or equal to half the fourth arc length, the third amplitude being smaller than the fourth amplitude.
15 . The sensing element according to claim 1 , wherein the course of the fourth receiving conductor path has a third amplitude within a third section and a fourth amplitude within a fourth section, the third section extending over a third angle starting from an end of the fourth receiving conductive path adjacent to the first gap, the fourth section extending over a fourth angle starting from another end of the fourth receiving conductive path adjacent to the second gap, each of the third angle and the fourth angle being less than or equal to half the fourth arc length, the third amplitude being smaller than the fourth amplitude.
16 . The sensing element according to claim 1 , wherein the second arc length and the fourth arc length are equal.
17 . The sensing element according claim 1 , wherein the second arc length and the fourth arc length are different lengths.
18 . The sensing element according to claim 17 , wherein the first gap length and the second gap length are equal.
19 . The sensing element according to claim 17 , wherein a first area spanned by the second receiving conductive path is as large as a second area spanned by the fourth receiving conductive path.
20 . The sensing element according to claim 17 , wherein the second arc length is greater than the fourth arc length, the course of the second receiving conductive path has a first amplitude, the course of the fourth receiving conductive path has a second amplitude, the first amplitude being smaller than the second amplitude.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to Application No. 23158097.8, filed in the European Patent Office on Feb. 23, 2023, which is expressly incorporated herein in its entirety by reference thereto. FIELD OF THE INVENTION The present invention relates to a sensing element for an inductive angle measuring device, e.g., for determining the position of a scale element relative to the sensing element. BACKGROUND INFORMATION Inductive position measuring devices are used, for example, as angle measuring devices to determine an angular position of machine parts that can be rotated relative to one another. In inductive position measuring devices, excitation tracks and receiving tracks, for example, in the form of conductive paths, are often applied to a common printed circuit board which usually has multiple layers and is firmly connected, for example, to a stator of the position measuring device. Opposite this printed circuit board is a scale element on which graduation structures are applied and which is firmly connected to a movable part of the position measuring device. When a time-varying electrical excitation current is applied to the excitation tracks, signals dependent on the position are generated in the receiving tracks during the relative movement between the scale element and the sensing element. These signals are further processed in an evaluation electronics system. A sensing element for an inductive angle measuring device is described in and illustrated in FIG. 7 of PCT Patent Document No. WO 2018/002568. The sensing element device has several detector units that extend along a circular line in segments separated by gaps. SUMMARY Example embodiments of the present invention provide a comparatively accurately operating, compact, and inexpensively producible sensing element for an inductive angle measuring device. According to example embodiments, the sensing element, which is intended and adapted for use in an inductive angle measuring device, has a first, second, third, and fourth detector unit. The first detector unit includes a first receiving conductive path extending over a first arc length. The second detector unit includes a second receiving conductive path, which extends over a second arc length. The third detector unit includes a third receiving conductive path extending over a third arc length. The fourth detector unit includes a fourth receiving conductive path, which extends over a fourth arc length. The curve of the first receiving conductive path and the curve of the third receiving conductive path are periodic in the circumferential direction along a first circular line, which has a first radius. The curve of the second receiving conductor path and the curve of the fourth receiving conductive path are also periodic in the circumferential direction along a second circular line, which has a second radius. The second and the fourth receiving conductive paths are arranged such that there is a first gap with a first gap length and a second gap with a second gap length between them in the circumferential direction. The first radius and the second radius are of different sizes. In addition, either a) the first gap length and the second gap length are of different sizes, or b) the second arc length and the fourth arc length are of different sizes. In an angle measuring device, the sensing element is used to determine an angular position relative to a scale element, and the scale element is arranged rotatably around an axis relative to the sensing element, so that the measuring direction represents the circumferential direction with respect to the axis. The arc lengths and the gap lengths are measured in degrees and refer to a respective center angle around the axis or around the common center point of the concentrically arranged first and second circular lines. The detector units and, for example, the receiving conductive paths extend along the circumferential direction. The second and fourth receiving conductive paths, e.g., those that generate in-phase signals, are analogously connected with each other to form sum signals. The same applies to the signals of the first and third receiving conductive paths. For example, the second and fourth receiving conductive paths each have a periodic curve with a constant second period length λ2. The first gap length β24 is a multiple m of the second period length λ2 and the second gap length γ24 is a multiple n of the second period length λ2 (β24=m·λ2 and γ24=n·λ2, in which m and n are natural numbers greater than zero). For example, the second period length λ2 is an integer second divisor of 360°, and the second divisor is, for example, an odd number. For example, the second arc length α2 and the fourth arc length α4 are multiples p, q of the second period length λ2 (α2=p·λ2 and α4=q·λ2, in which p and q are natural numbers greater than zero). For example, the first and the third receiving conductive paths are ar