ROLLING ELEMENT FOR USE IN A ROLLING-ELEMENT BEARING

Abstract

A rolling element for use in a rolling-element bearing is proposed, including an outer casing and a bore hole. The bore hole is provided along a center line of the rolling element. The rolling element has at least one sensor arranged in the bore hole for load measurement and a radio module for transmitting the data measured by the sensor, wherein the rolling element has a micro-generator to provide the energy required for operation of the sensor and/or of the radio module.

Claims

1.-10. (canceled)

11. A rolling element for use in a rolling-element bearing, comprising: an outer casing and a bore hole, the bore hole having a bore wall arranged about a centerline of the rolling element; a sensor arranged in the bore hole, the sensor configured to measure load; a radio module configured to transmit data measured by the sensor; and and a micro-generator configured to provide the energy required for operation of the sensor and/or of the radio module.

12. The rolling element of claim 11, wherein the sensor is a capacitive sensor configured to measure a distance between the sensor and the bore wall.

13. The rolling element of claim 11, including two sensors arranged along the centerline at a distance from one another.

14. The rolling element of claim 11, including means for producing a defined distance from the bore wall disposed in an axial direction and at a level of the sensor.

15. The rolling element of claim 14, wherein the means for producing a defined distance from the bore wall is disposed opposite the sensor with respect to the centerline.

16. The rolling element of claim 14, wherein the means for producing a defined distance from the bore wall includes a magnet.

17. The rolling element of claim 14, including a circuit board arranged in the bore hole, wherein one or more of the radio module, the micro-generator, the capacitive sensor and the means for producing a defined distance is attached to the circuit board.

18. The rolling element of claim 11, wherein the radio module is provided to transmit the measured data in a frequency range of from 100 MHz to 6 GHz.

19. The rolling element of claim 11, wherein the radio module is provided to transmit the measured data in a frequency range of 833 MHz.

20. The rolling element of claim 11, wherein the bore hole comprises a diameter of about 5 mm to about 50 mm, and/or the rolling element is cylindrical and comprises a length of about 90 mm to about 110 mm and a diameter from about 60 to about 70 mm.

21. The rolling element of claim 11, wherein the bore hole comprises a diameter of about 10 to about 30 mm, and/or the rolling element is cylindrical and comprises a length of about 104 mm and a diameter of about 65 mm.

22. The rolling element of claim 11, wherein the bore hole comprises a diameter of about 20 mm, and/or the rolling element is cylindrical and comprises a length of about 104 mm and a diameter of about 65 mm.

23. The rolling element of claim 11, comprising a strain gage arranged in an at least partially circumferential manner on the bore wall in the radial direction.

24. The rolling element of claim 11, wherein the rolling element has a means for determining position.

25. A rolling-element bearing, comprising: a first bearing ring; a second bearing ring which is rotatable about an axis of rotation and is arranged concentrically with the first bearing ring; and a plurality of rolling elements arranged between the first bearing ring and the second bearing ring, wherein each of the plurality of rolling elements are constructed according to the rolling element of claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a schematic perspective view of a rolling element according to an exemplary embodiment of the present invention.

[0024] FIG. 2 is another schematic perspective view of a rolling element according to an exemplary embodiment of the present invention.

[0025] FIG. 3 is a schematic sectional view perpendicular to the centerline of a rolling element according to an exemplary embodiment of the present invention comprising a cage of a rolling-element bearing.

[0026] FIG. 4 is a schematic sectional view parallel to the centerline of a rolling element according to an exemplary embodiment of the present invention.

[0027] FIG. 5 is a schematic equivalent circuit diagram of the coils from FIGS. 3 and 4 according to an exemplary embodiment of the present invention.

[0028] FIG. 6 is a schematic cross section of a bore hole of a rolling element according to an exemplary embodiment of the present invention.

[0029] FIG. 7 shows a circuit board of a rolling element according to an exemplary embodiment of the present invention.

[0030] FIG. 8 is a schematic perspective view of a rolling element according to an exemplary embodiment of the present invention.

[0031] FIG. 9 is a schematic perspective view of a circuit board of a rolling element according to an exemplary embodiment of the present invention.

[0032] FIG. 10 is a perspective view of a rolling-element bearing according to an exemplary embodiment of the present invention.

[0033] FIG. 11 is a perspective detailed view of a rolling-element bearing according to an exemplary embodiment of the present invention.

EMBODIMENTS OF THE INVENTION

[0034] In the different drawings, like parts are always provided with the same reference signs and therefore are generally also named or mentioned only once in each case.

[0035] FIG. 1 is a schematic perspective view of a rolling element 1 according to an exemplary embodiment of the present invention. A rolling element 1 of this type is used in rolling-element bearings and is used to movably guide a first bearing ring 11 and a second bearing ring 12 relative to one another, in particular an inner ring 12 arranged in an outer ring 11 which is arranged in a rotationally fixed manner. In this case, a plurality of rolling elements are conventionally provided between the outer ring 11 and the inner ring 12, which elements roll on running surfaces of the outer ring 11 and the inner ring 12. The present case relates to what is known as a measuring roller, that is to say a rolling element 1, which is provided and designed for measuring loads in the rolling-element bearing.

[0036] In this case, the rolling element 1 comprises a cylindrical or substantially conical body having an outer casing 2 which is used as a running surface and on which the outer ring 11 and the inner ring 12 roll. The rolling element 1 has a bore hole 3 in the center thereof which is formed concentrically around the centerline of the rolling element 1. A plurality of coils 10, which in this case are arranged on a circular path between the bore hole 3 and the outer casing 2, can additionally be seen. In this case, there are fourteen coils 10, which are each arranged so as to be offset by approx. 25°, a magnetic field which is directed in the opposite direction in each case being generated by applying a current or a voltage. A resonant circuit is produced by applying an alternating voltage. Said circuit will be described in greater detail in connection with the following drawings.

[0037] Furthermore, the rolling element 1 comprises a means for determining position 16, in this case a diametral magnet, which cooperates with a detection means to determine the absolute and/or relative position of the rolling element 1 in the rolling-element bearing. In this case, for example, the cage 13 comprises the detection means. In this case, the relative position is the position of the rolling element 1 relative to the cage 13, in particular relative to a reference point.

[0038] FIG. 2 is another schematic perspective view of a rolling element 1 according to an exemplary embodiment of the present invention. In this case, the embodiment shown substantially corresponds to the embodiment shown in FIG. 1, and therefore reference is made generally to the comments in this regard. It can clearly be seen here that the rolling element 1 is substantially cylindrical. In the bore hole 3, a measuring arrangement which is to be explained in greater detail in the following is provided.

[0039] FIG. 3 is a schematic sectional view perpendicular to the centerline of a rolling element 1 according to an exemplary embodiment of the present invention comprising a cage 13 of a rolling-element bearing. In this case, the embodiment shown substantially corresponds to the embodiments shown in the previous drawings, and therefore reference is made generally to the comments in this regard. In the bore hole, a sensor 5, in this case a capacitive sensor 5, a radio module 6 and a micro-generator 4 are provided. In this case, the micro-generator is an inductive micro-generator. So that the rolling elements of a rolling-element bearing remain at a regular distance for a uniform load distribution, a cage 13 is arranged between the outer ring 11 and the inner ring 12, which cage comprises the rolling elements. This means that the rolling elements are rotatable but are mounted in fixed positions with respect to the cage 13. At the point of the rolling element 1, the cage 13 has magnets 15, in this case four magnets 5. Said magnets 15 make it possible to induce a current in the micro-generator 4 and thus provide an energy supply for the sensor 5 and the radio module 6 as well as the coils 10. Alternatively or additionally, and in the context of the present invention preferably, the micro-generator is provided in such a way that said micro-generator generates energy solely from the movement, i.e. the rolling, of the rolling element.

[0040] The sensor 5 is arranged on a circuit board 8 (not shown here). On the other side of the circuit board 8, i.e. opposite the sensor 5 with respect to the centerline, a means 7 is arranged for producing a defined distance from the bore wall. In this case, said means 7 is a rolling contact block having a magnet 14 arranged therein. The magnet ensures that the rolling contact block comes into contact with the bore wall, since it is attracted alternately by the magnetic fields of the coils 10. As a result, the means 7 comprising the circuit board 8 and thus also the sensor 5 performs an oscillation, the frequency of which depends firstly on the coils 10 and secondly on the distance between the means 7 and the bore wall or the distance between the sensor 5 and the bore wall, and of course on the properties of the rolling contact block, e.g. the mass thereof and the strength of the magnet 14. The capacitive sensor 5 thus measures a frequency that corresponds to a distance from the bore wall. If the rolling element 1 is then deformed by forces, i.e. loads, acting on the rolling element 1, then the bore hole 3 deforms as well. The distance between the capacitive sensor 5 and the bore wall thus changes, and the measured frequency also changes together therewith. The measured frequency is transmitted to the radio module 6, which transmits said frequency wirelessly from the rolling element. It is also conceivable for a deformation or load to be determined from the measured data beforehand, which deformation or load is then transmitted.

[0041] FIG. 4 is a schematic sectional view parallel to the centerline of a rolling element 1 according to an exemplary embodiment of the present invention. In this case, the embodiment shown substantially corresponds to the embodiment shown in FIG. 3, and therefore reference is made generally to the comments in this regard. In particular the bore hole 3 can be seen here, and the micro-generator 4 and the radio module 6 are shown schematically.

[0042] FIG. 5 is a schematic equivalent circuit diagram of the coils 10 from FIGS. 3 and 4 according to an exemplary embodiment of the present invention. In this case, the coils 10 represent resistors which are connected in series. According to the drawings described previously, fourteen coils 10, accordingly fourteen resistors, are provided in this case.

[0043] FIG. 6 is a schematic cross section of a bore hole 3 of a rolling element 1 according to an exemplary embodiment of the present invention. The circuit board 8 can be seen clearly here, the capacitive sensor 5 being arranged on one side of the circuit board 8, and the means 7 comprising the magnet 14 being arranged on the other side. In addition, various deformations or distances d are drawn in. In the embodiment shown, the distance d.sub.0 between the capacitive sensor 5 and the bore wall in a load-free state is approx. 100 μm, the magnet 14 of the means 7 having brought the rolling contact block into contact with the bore wall. Depending on whether the bore hole is distorted or compressed, the distance, that is to say the deformation, changes between a minimum value d.sub.min of 50 μm and a maximum value d.sub.max of 150 μm. On the left-hand side of the drawing, a resonant circuit is shown schematically. In this regard, reference is made to the comments regarding FIG. 4. In this case, the capacitive sensor 5 and the rolling contact block have, at least in part, an outer contour which follows the contour of the bore wall in a load-free state, that is to say which is concentric with the bore wall.

[0044] FIG. 7 shows a circuit board 8 of a rolling element 1 according to an exemplary embodiment of the present invention. For reasons of clarity, not all the elements are shown in this case. In the center, the point which is provided for attaching the micro-generator 4 is visible. On both sides of said point and on both edges of the circuit board 8, attachment points can be seen, which are used to attach two capacitive sensors 5, 5′. These two sensors 5, 5′ which are at a distance from one another along the centerline allow a measurement relative to one another and thus, in addition to a pure force measurement along three axes, also allow the measurement of a tipping of the rolling element 1, that is to say a deformation of the rolling element 1 which has different strengths along the centerline. Furthermore, a radio module 6 is shown merely by way of example. The circuit board 8 is dimensioned in such a way that it fits into the bore hole 3 and preferably comprises a small lateral tolerance.

[0045] FIG. 8 is a schematic perspective view of a rolling element 1 according to an exemplary embodiment of the present invention. In this case, the embodiment shown substantially corresponds to the embodiments shown in the previous drawings, and therefore reference is made generally to the comments in this regard. In particular, the circuit board 8 inserted in the bore hole 3 comprising the sensor 5 and the means 7 can be seen well here.

[0046] FIG. 9 is a schematic perspective view of a circuit board 8 of a rolling element 1 according to an exemplary embodiment of the present invention. In this case, the embodiment shown substantially corresponds to the embodiment shown in FIG. 7, and therefore reference is made generally to the comments in this regard. Two capacitive sensors 5, 5′ and accordingly two means 7, 7′ in the form of rolling contact blocks are also provided here. In addition, it can clearly be seen where the magnet 14 is inserted in the means 7, this being merely an example of an attachment option.

[0047] FIG. 10 is a perspective view of a rolling-element bearing according to an exemplary embodiment of the present invention. In this case, said rolling-element bearing is a large rolling-element bearing comprising an outer ring 11, an inner ring 12 (not shown here for reasons of clarity) and a cage 13 which is arranged therebetween which has a plurality of rolling elements and keeps said elements at a uniform distance from one another. At least one rolling element in this case is a rolling element 1 within the meaning of this application, that is to say a measuring roller.

[0048] FIG. 11 is a perspective detailed view of a rolling-element bearing according to an exemplary embodiment of the present invention. In particular, a rolling element 1 according to the invention is shown here, in addition to two conventional rolling elements. As can be seen from the drawing, the rolling element 1 has no wiring, said element functions autonomously and transmits the measured data wirelessly, and therefore the rolling-element bearing can be surrounded for example by a housing, and a load measurement is still possible. As a result, the large rolling-element bearing can be installed for example in a wind turbine and transmit load measurement data to a control unit so that a need for maintenance can be detected in good time and without complex interventions in the rolling-element bearing.

LIST OF REFERENCE NUMERALS

[0049] 1 rolling element

[0050] 2 outer casing

[0051] 3 bore hole

[0052] 4 micro-generator

[0053] 5, 5′ sensor

[0054] 6 radio module

[0055] 7, 7′ means for producing a defined distance from the bore wall

[0056] 8 circuit board

[0057] 9 strain gage

[0058] 10 coils

[0059] 11 outer ring

[0060] 12 inner ring

[0061] 13 cage

[0062] 14 magnet

[0063] 15 cage magnets

[0064] 16 means for determining position

[0065] d deformation