Rolling bearing having position-determining device
View Patent ↗A rolling bearing may have at least two bearing rings arranged rotatably relative to each other, at least one row of rolling elements arranged such that they can roll between the bearing rings, and a position-determining device for determining an absolute angular position of the bearing rings relative to each other. The position-determining device includes field patterns that are arranged on a surface of a first of the bearing rings and distributed around a circumference thereof, with fields of the field patterns having field heights with discrete values. The position-determining device also includes at least one eddy current sensor that is provided on a second of the bearing rings to scan the field patterns. An evaluation device may be configured to assign an associated angular position signal, which describes the absolute angular position of the first and second bearing rings relative to each other, to a scan of each field pattern.
1. A rolling bearing comprising:
bearing rings that are rotatable relative to each other;
a row of rolling elements configured such that the rolling elements can roll between the bearing rings; and
a position-determining device configured to determine an absolute angular position of the bearing rings relative to each other, wherein the position-determining device includes:
field patterns that are arranged on a surface of a first of the bearing rings and distributed around a circumference of the first bearing ring, wherein fields of the field patterns have field heights with discrete values, wherein each field pattern is a fixed arrangement of a predetermined number of fields in which positions of the fields relative to one another in the field pattern are fixed, and wherein the field patterns differ by the field height provided for each individual field,
an eddy current sensor on a second of the bearing rings to scan the field patterns, and
an evaluation device configured to assign an associated angular position signal, which describes the absolute angular position of the first and second bearing rings relative to each other, to a scan of each field pattern.
2. The rolling bearing of claim 1 wherein the field heights of the fields comprise at least one of depressions or elevations on the surface.
3. The rolling bearing of claim 1 wherein at a predefined position each field pattern contains an index field, with the field height at the index field differing from a surrounding surface.
4. The rolling bearing of claim 3 wherein the index fields are arranged on an index circle axially and/or radially separated from the other fields of the field pattern, wherein the eddy current sensor is dedicated to the index fields and is configured to only pass over the index fields as the rolling bearing rings rotate.
5. The rolling bearing of claim 4 wherein the eddy current sensor is a first eddy current sensor, wherein the evaluation device is configured to specify an evaluation instant for a measurement signal of a second eddy current sensor based on an evaluation of measurement signals of the first eddy current sensor assigned to the index fields.
6. The rolling bearing of claim 1 wherein the field heights of the field patterns have at least three discrete values.
7. The rolling bearing of claim 1 wherein the field patterns comprise a predefined number of fields, with each field being assigned exactly one eddy current sensor for scanning.
8. The rolling bearing of claim 1 wherein the fields of the field patterns comprise field areas that are larger than an active sensor surface of the eddy current sensor.
9. The rolling bearing of claim 1 wherein the evaluation device is configured to use measurement values of the eddy current sensor recorded outside of field patterns in determining the angular position signal to compensate for load-dependent deformations of the bearing rings.
10. The rolling bearing of claim 1 wherein the field patterns comprise a metal sheet fixed to the first bearing ring.