BEARING AND METHOD FOR MONITORING WEAR AND/OR MEASURING A LOAD

Abstract

A bearing or rolling bearing may comprise a stationary first bearing ring and a second bearing ring that is arranged in a rotatable manner about a longitudinal axis relative to the first bearing ring. The bearing may have a first sensor and a second sensor, which are contactless measuring sensors. The first sensor and the second sensor may each have a sensor surface. The first sensor may be positioned opposite an at least partly circumferential reference edge, and the second sensor may be positioned opposite a reference surface. The first sensor can measure a degree of overlap between the sensor surface of the first sensor and the reference edge. The second sensor can measure a distance, in particular a radial distance, between the sensor surface of the second sensor and the reference surface.

Claims

1.-10. (canceled)

11. A bearing comprising: a stationary first bearing ring; a second bearing ring that is rotatable about a longitudinal axis relative to the stationary first bearing ring; a first sensor disposed opposite an at least partly circumferential reference edge, with the first sensor having a sensor surface, wherein the first sensor is configured to measure a degree of overlap between the at least partly circumferential reference edge and the sensor surface of the first sensor; and a second sensor disposed opposite a reference surface, with the second sensor having a sensor surface, wherein the second surface is configured to measure a distance between the reference surface and the sensor surface of the second sensor, wherein the first and second sensors are contactless measuring sensors.

12. The bearing of claim 11 configured as a rolling bearing.

13. The bearing of claim 11 wherein the distance that the second sensor measures is a radial distance between the reference surface and the sensor surface of the second sensor.

14. The bearing of claim 11 wherein the sensor surface of at least one of the first sensor or the second sensor is an end face of the at least one of the first sensor or the second sensor.

15. The bearing of claim 14 wherein the end face has a circular shape.

16. The bearing of claim 11 wherein at least one of the first sensor or the second sensor is at least one of a capacitive measuring sensor, an inductive measuring sensor, an ultrasound sensor, or an eddy current sensor.

17. The bearing of claim 11 wherein a plurality of the first sensor and/or the second sensor is disposed along a circumference of at least one of the stationary first bearing ring or the second bearing ring.

18. The bearing of claim 11 wherein at least one of the first sensor or the second sensor is disposed at least partly in a bore in at least one of the stationary first bearing ring or the second bearing ring.

19. The bearing of claim 11 configured as a multiple-row rolling bearing.

20. The bearing of claim 11 configured as a slewing ring.

21. The bearing of claim 11 configured as a three-row rolling rotary connection.

22. A method for monitoring wear and/or measuring a load with the bearing of claim 11, wherein during a rotation of the second bearing ring relative to the stationary first bearing ring, the first sensor measures the degree of overlap between the at least partly circumferential reference edge and the sensor surface of the first sensor and the second sensor measures the distance between the reference surface and the sensor surface of the second sensor.

23. The method of claim 22 comprising filtering data measured by at least one of the first sensor or the second sensor so as to distinguish wear from a load-induced deformation.

24. The method of claim 22 wherein at least one of the first sensor or the second sensor measures continuously.

25. The method of claim 22 wherein at least one of the first sensor or the second sensor measures periodically.

26. The method of claim 22 wherein the bearing ring comprises a plurality of the first sensor and/or a plurality of the second sensor disposed along a circumference of the stationary first bearing ring, wherein the plurality of the first sensor and/or the plurality of the second sensor are interconnected and/or measured data is evaluated such that tilting the stationary first bearing ring relative to the second bearing ring is detectable.

27. The method of claim 22 wherein the bearing ring comprises a plurality of the first sensor and/or a plurality of the second sensor, wherein the plurality of the first sensor and/or the plurality of the second sensor are interconnected and/or measured data is evaluated such that tilting the stationary first bearing ring relative to the second bearing ring is detectable.

28. The method of claim 22 comprising evaluating data measured from the first sensor and the second sensor to detect tilting of the stationary first bearing relative to the second bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a perspective cross-sectional drawing of a bearing according to one exemplary embodiment of the present invention.

EMBODIMENTS OF THE INVENTION

[0026] In the various figures, the same parts are always denoted with the same reference numbers and are therefore generally cited or mentioned only once.

[0027] FIG. 1 illustrates a perspective cross-sectional drawing of a bearing according to one exemplary embodiment of the present invention. The bearing here is a slewing ring such as is used for example, but not exclusively, in wind turbines. Such a slewing ring has for example an outer diameter of around 2.5 m. Other areas of application and other bearing designs, such as those with intermeshing teeth instead of roller bodies, or a swivel bearing instead of a rotary bearing, are likewise possible, of course.

[0028] The bearing has a static, i.e., fixed or stationary first bearing ring 1, here, an outer ring 1, as well as a second bearing ring 2 arranged concentrically in the outer ring 1, here, an inner ring 2. The inner ring 2 here is rotatable about an axis of rotation or longitudinal axis running centrally through the inner ring 2, i.e., the inner ring 2 is rotatable with respect to the outer ring 1. In the outer ring 1 there are provided two continuous bores at a spacing from each other and running in the radial direction, a first sensor 3 and a second sensor 4 being arranged in the bores. The sensors 3, 4 in the present instance are eddy current sensors. The sensors 3, 4 are substantially rod-shaped and secured in the bores, e.g., by gluing. The sensors 3, 4 have an end face, being circular here, which corresponds to a sensor surface 7.

[0029] The first sensor and the second sensor are arranged with respect to the inner ring 2 such that the first sensor 3 lies opposite the middle of a reference edge 5. The reference edge 5 is preferably step-shaped, as depicted here, and it has in particular a 90 angle to the edge. The reference edge 5 borders on two regions, one region with a small distance from the sensor surface 7 and one region with a large distance from the sensor surface 7. The two regions are situated parallel to each other and parallel to the sensor surface 7 of the first sensor 3.

[0030] The second sensor 4 is arranged such that it lies opposite a reference surface 6, wherein the sensor surface 7 of the second sensor 4 is oriented parallel to the reference surface 6. The reference surface 6 may be a running surface, i.e., a surface on which for example the first bearing ring 1 and the second bearing ring 2 roll against each other or against the roller bodies which are in contact with the first bearing ring 1 and the second bearing ring 2. The reference edge 5 and the reference surface 6 here are adjacent to each other and fashioned as part of a groove, having for example a width of around 12 mm to 15 mm. Accordingly, the first sensor 3 and the second sensor 4 here have a diameter of around 12 mm to 15 mm, wherein in particular the first sensor 3 is identical in design to the second sensor 4, so that the second sensor 4 fits into the groove without the reference edge 5 lying in a radial projection onto the sensor surface 7 of the second sensor 4. This means that the second sensor only measures a distance to the reference surface 6.

[0031] The eddy current sensors preferably comprise, in addition to a sensor unit for detecting an eddy current density, in particular by a measurement of magnetic fields, an exciter coil, which generates high-frequency fields when an alternating current is applied. These high-frequency fields induce eddy currents in the material being probed, i.e., in this case the material in the area of the reference edge 5 or the material in the area of the reference surface 6. These, in turn, generate magnetic fields, which are detected by the eddy current sensors. The magnetic fields are dampened by the distance between the reference edge 5 and the sensor surface 7 of the first sensor 3 or between the reference surface 6 and the sensor surface 7 of the second sensor 4, i.e., the detectable magnetic field strength has a lesser amplitude in particular. The gap between material and sensor 3, 4 may be for example an air gap and/or be filled at least partly with a lubricant. Thus, by the eddy current measurement, it is possible to determine the distance between the material and the sensors 3, 4. The reference edge 5 and the reference surface 6, or the material in these areas, is at least partly electrically conductive, i.e., at least partly made of an electrically conductive material. In this way, the second sensor 4 can measure a distance between its end face, i.e., the sensor surface 7, and the reference surface 6. A change in this distance, for example a decreasing of the distance, then points to wear or a load acting on the bearing.

[0032] The first sensor 3 measures a degree of overlap of the reference edge 5 with the sensor surface 7. Since the reference edge 5 lies in a radial projection in the region of the sensor surface 7 of the first sensor 3, the first sensor 3 measures in part both a small distance from the higher region of the reference edge 5 and also in part a larger distance from the lower region of the reference edge 5. Thus, the degree of overlap indicates which portion of the sensor surface 7 is overlapped by which region of the reference edge, or in other words where the reference edge 5 is situated in a radial projection on the sensor surface 7. This is expressed by a combined distance measurement from the two regions of the reference edge 5. Under an axial load or under axial wear, the first bearing ring 1 and the second bearing ring 2 are displaced relative to each other in the axial direction, i.e., the position of the reference edge 5 changes in relation to the sensor surface 7. Accordingly, the degree of overlap changes. In particular, by taking into account the distance from the reference surface 6 as measured by the second sensor 4, which preferably corresponds to the distance from the lower region of the reference edge 5, it is thus possible to determine information as to the axial (relative) displacement.

[0033] The skilled person understands that, by an appropriate interconnection of a plurality of first sensors 3 and/or a plurality of second sensors 4, further measurements become possible, such as a measurement of a tilting between inner ring 2 and outer ring 1. In the event of a tilting about a point of the (original) longitudinal or rotation axis, for example, two first sensors 3 arranged with an offset of 180 around the circumference would measure opposite changes in the degree of overlap. Two further first sensors 3, in turn arranged with an offset of 180 to each other, but 90 from the previously described first sensors 3, on the other hand in the optimal situation, i.e., in an optimal orientation of the sensors relative to the tilting axis, would measure no change or at least the same change in the degree of overlap.

[0034] In particular, a distinct division into an axial and a radial displacement component is made possible by a combination of the measurement results of the first sensor 3 and the second sensor 4.

LIST OF REFERENCE NUMBERS

[0035] 1 First bearing ring, outer ring

[0036] 2 Second bearing ring, inner ring

[0037] 3 First sensor

[0038] 4 Second sensor

[0039] 5 Reference edge

[0040] 6 Reference surface

[0041] 7 Sensor surface