Bearing arrangement

Abstract

Disclosed is a bearing arrangement (1) having an inner ring (2) and an outer ring (4) which are rotatable relative to one another, wherein the inner ring (2) is arranged on a first component (8) and the outer ring (4) is arranged in a second component (10), wherein the bearing arrangement (1) comprises a sensor for detecting micro-movements of the inner ring (2) with respect to the first component (8) and / or micro-movements of the outer ring (4) with respect to the second component (10), wherein the sensor (12-1, 12-2) comprises at least a first and at least a second sensor element (14-1, 14-2, 16-1, 16-2), wherein the first sensor element (14-1, 14-2) is arranged on the first component (8) and / or the second component (10) and wherein the second sensor element (16-1, 16-2) is arranged on the inner ring (2) and / or the outer ring (4), wherein the first sensor element (14-1, 14-2) is designed to detect an offset of the second sensor element (16-1,16-2) with respect to the first sensor element (14-1, 14-2).,

Description

Technical FieldThe present invention relates to a bearing arrangement having an inner ring and an outer ring according to the preamble of claim 1.Background ArtIn bearing assemblies having an inner ring and an outer ring that rotate relative to each other, the inner ring is typically disposed on a first component and the outer ring is disposed in a second component. The first component may be a shaft, for example, and the second component may be a housing, in which case the first component rotates and the second component is stationary. Other arrangements in which the first component is fixed and the second component rotates are also possible. In any case, the inner ring is fixedly connected to the first component, e.g. a shaft, and the outer ring is fixedly connected to the second component, e.g. a housing. The connection between the inner ring or outer ring and the respective component can be, in particular, a fit, for example, an interference fit, a press fit, or also a material or form fit.During the operation of the bearing arrangement, micromovements can occur between the inner ring or the outer ring and the respective component. These micromovements, so-called creep or migration of the rings, can lead to damage to the rings and the components over the long term, such as, for example, corrugations, cold welds or the like. Ring migrating can occur in both rotational directions, regardless of the actual rotational direction of the bearing assembly. In the extreme case, the micromovements can lead to loosening, or due to material loosening, of the respective ring, which means that the function of the bearing can no longer be ensured. It is therefore necessary to be able to detect micromovements of the bearing rings with respect to the respective components to which they are fastened at an early stage. Until now, a manual inspection of the markings on the bearing rings or the corresponding components, such as shaft or housing, which are produced as a result of the creep movements, has been required here.It is therefore an object of the present invention to provide a reliable and automated detection of micromovements of bearing rings with respect to components to which the bearing rings are fastened.SUMMARY OF THE INVENTIONThis object is achieved by a bearing arrangement according to claim 1.The bearing arrangement has an inner ring and an outer ring which are rotatable relative to one another. The bearing arrangement can be a rolling bearing or a sliding bearing, wherein in the former case rolling bodies can be arranged between the inner ring and the outer ring, for example rollers or balls. The inner ring is arranged on a first component, for example a shaft, and the outer ring is arranged in a second component, for example a housing.Ideally, when the inner ring is fixedly connected to the first component and the outer ring is fixedly connected to the second component, e.g., by press-fitting, the inner ring does not move with respect to the first component and the outer ring does not move with respect to the second component. When the bearing is loaded, the described micromovements can occur. As already explained above, such ring wander / micromovements can lead to damage to the rings and the components. In order to be able to detect such micromovements in good time, the bearing arrangement has a sensor for detecting micromovements of the inner ring with respect to the first component and / or micromovements of the outer ring with respect to the second component.The sensor comprises at least one first and at least one second sensor element, wherein the first sensor element is arranged on the first component and / or the second component and wherein the second sensor element is arranged on the inner ring and / or the outer ring. In particular, the first sensor element is provided on the first component and the second sensor element is provided on the inner ring in order to detect micromovements of the inner ring with respect to the first component. In order to detect micromovements of the outer ring with respect to the second component, the first sensor element is arranged on the second component and the second sensor element is arranged on the outer ring.The first sensor element is configured to detect an offset of the second sensor element with respect to the first sensor element. Once such an offset occurs, this is interpreted as micromovements of the corresponding ring with respect to the corresponding component. This is possible since one sensor element is always arranged on one component and the other sensor element is arranged on the corresponding ring, so that an offset between the two sensor elements indicates an offset between the respective ring and the corresponding component.In this way, it is possible not only to detect creep effects by manual / visual inspection of the bearing elements, but also to detect micromovements, which can lead to creep effects and thus to potential damage to the bearing elements, in real time during operation, and to obtain knowledge about the influencing variables such as load, temperature, fit, etc. This knowledge can either be used in advance, for the specific design configuration of the bearing, or during operation, in order to be able to take appropriate maintenance measures in good time.In particular, an offset of the second sensor element with respect to the first sensor element in the rotational direction and / or counter to the rotational direction of the bearing arrangement can be detected starting from an initial position. In particular, the micromovements can be back and forth movements. At the beginning of the operation of the bearing arrangement, an initial position of the second sensor element can thus be detected by the first sensor element and an offset with respect to this initial position can be detected during the operation of the bearing arrangement.According to a further embodiment, the inner ring and / or the outer ring have a groove in which the second sensor element is arranged, wherein the groove faces the first sensor element. This has the advantage that the second sensor element, in particular if it is in the form of a band, can be fastened in the groove in a protected manner to the inner ring and / or the outer ring.According to a further embodiment, the first component and / or the second component have a cutout in which the first sensor element is arranged. Alternatively, the first component and / or the second component can have a holding device to which the first sensor element is fastened. In both cases, the first sensor element is arranged in each case such that it does not move relative to the first or the second component and is securely fastened to the respective component. Since the first sensor element is fixedly attached to the first or second component and the second sensor element is fixedly attached to the inner ring or the outer ring, the first sensor element can detect a movement of the second sensor element relative to the first sensor element during sensing of the second sensor element, which movement corresponds to a relative movement between the inner ring and the first component or between the outer ring and the second component.The first sensor element is preferably arranged such that it does not contact the second sensor element. In order to compensate for manufacturing tolerances, corresponding adjustment options can be provided, in particular when a holding device is used, in order to be able to adapt the first sensor element in a plurality of degrees of freedom. Preferably, an adjustment in five degrees of freedom can be provided, for example by a three-point support in two axes each. The more flexible the adjustment possibility is, i.e., the more degrees of freedom of adjustment are present, the better the manufacturing tolerances can be compensated.Since the linear velocity and the total distance between the first and the second sensor element are very small in such a bearing arrangement, contact between the first and the second sensor element can also be tolerated, since these are not strong opposing movements. Ideally, as long as there are no micromovements, the first sensor element does not move with respect to the second sensor element. A suspension may also be provided in order to generate a constant contact force between the first and the second sensor element.According to one embodiment, the first sensor element is a sensor head and the second sensor element is a magnetically encoded sensor body, wherein the sensor head is arranged facing the sensor body. The sensor head represents a detection element that is capable of sensing a magnetically encoded sensor body. For example, the sensor head may have a sampling rate of 1 kHz or more, preferably more than 30 kHz, in order to provide a high resolution of the detection. Such a high temporal resolution makes it possible to be able to detect even the fastest movements, i.e. micromovements, as occur in ring-type wanders.According to a further embodiment, the magnetically encoded sensor body is a magnetically encoded band, wherein the band is arranged on the outer ring and / or on the inner ring. Here, the band is preferably arranged in a groove which is respectively provided on the outer periphery of the outer ring and / or the inner ring, as described above. This is advantageous since the band can be tensioned around the outer circumference during assembly and thus securely fastened. Alternatively, however, it is also possible to mount it on the inner periphery of the respective ring.According to another embodiment, the band is an open ring. The bearing arrangement may in this case comprise a fastening element configured to connect the two ends of the band. The fastening element is preferably designed in such a way that it forms a flat transition with the band with respect to the first sensor element, e.g. the sensor head. This has the advantage that the sensor head, in particular if it has contact with the sensor body or strip, can move theoretically along the strip without noticing a transition between strip and fastening element. The sensor head is therefore not disturbed or even damaged in its movement by the fastening element.Preferably, the fastening element is designed to secure the two ends of the band on a side of the fastening element which is remote from the sensor head. The fastening element can be arranged in a depression in the groove on the respective ring, wherein the fastening element presses the two ends of the band into this depression. The fastening element can then be secured in this depression again by fixing elements or the like. Since the two ends of the band are secured in this recess by the fastening element, there is no risk that the two ends will be detached.The fastening element can produce a section at which the sensor head cannot read the tape and therefore cannot sample information. Therefore, the sensor according to an embodiment may include two sensor bodies arranged at a distance in the circumferential direction from each other that is larger than the extension of the fastening element in the circumferential direction. In this way, the two sensor heads can always read redundant position information from the tape. If one of the sensor heads is positioned in the area of the fastening element, the other sensor head will nevertheless be able to provide valid position information. In a read / data acquisition unit, the information of the two sensor heads can be interpreted and it can be decided which sensor value represents a correct position.In order to enable a particularly accurate detection of micromovements, the sensor can be calibrated, when using two first sensor elements, e.g. sensor heads, in order to take into account correctly, in particular, the non-readable region of the fastening element. For this purpose, two sensor heads are mounted on a calibration plate at a fixed distance from one another, so that the second sensor head SH[ 2] delivers a greater measurement value than the first sensor head SH( 1). When the sensor heads with the calibration plate are placed over the sensor body MCMB, SH2(MCMB)-SH1(MCMB) gives the effective (positive) distance between the sensor heads on the calibration plate. The calibration plate is then moved over the fastening element. In this position, SH1(fastener)-SH2(fastener) provides the (positive) spacing of the entire perimeter without the spacing of the sensor heads on the calibration plate. From this, {SH2(MCMB)-SH1(MCMB)}+{SH1(fastener)-SH2(fastener)} yields the full effective scope that can be scaled to creep information. This also allows the indication of a creep angle.Further advantages and advantageous embodiments are specified in the description, the drawings and the claims. In this case, in particular the combinations of the features indicated in the description and in the drawings are purely exemplary, and therefore the features can also be present individually or in a different combination.Brief description of the FiguresThe invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of protection of the invention. This is defined solely by the appended claims.The following are shown: FIG. 1 : a sectional view of a bearing arrangement with an inner ring and an outer ring; FIG. 2 : a sectional view of the bearing arrangement of FIG. 2 with sensors; and FIG. 3 : a perspective view of a fastening of a sensor element of the sensors of FIG. 2.DETAILED DESCRIPTION OF THE INVENTIONIn the following, elements that are the same or functionally the same are identified by the same reference numerals.FIG. 1 shows a bearing arrangement 1 with an inner ring 2 and an outer ring 4. It should be noted, however, that the bearing arrangement 1 can also be a slide bearing without rolling bodies or any desired rolling bearing, for example a ball bearing, a spherical roller bearing, etc.The inner ring 2 and the outer ring 4 are rotatable relative to each other. The inner ring 2 is arranged on a first component 8. The first component 8 may be, for example, a shaft or sleeve or the like that rotates in a rotational direction R together with the inner ring 2. The outer ring 4 is arranged in a second component 10. The second component 10 can be, for example, a housing or the like. The bearing rings 2, 4 are fastened to the two components 8, 10 by means of a fit. During operation, local flexing effects can occur, which cause a local movement between the bearing rings 2, 4 and the respective components 8, 10, so that micromovements occur between the inner ring 2 and the shaft 8 and / or between the outer ring 4 and the housing 10. This so-called ring migrating or creep can lead to wear, cold welding, or other functionally influencing changes on the rings 2, 4 and the components 8, 10.In order to be able to detect these micromovements at an early stage, the bearing arrangement 1 has one or two sensors 12- 1, 12- 2, as shown in FIG. 2. The sensor 12- 1 may be provided to detect micromovements between the outer ring 4 and the housing 10. Alternatively or additionally, the sensor 12- 2 may be provided to detect micromovements between the inner ring 2 and the shaft 8. In general, micromovements occur primarily on the ring which provides a revolving load, i.e., generally the rotating ring.Hereinafter, the sensors 12- 1, 12- 2 will be described together. The sensor 12- 1, 12- 2 has at least one first sensor element 14- 1, 14- 2 and at least one second sensor element 16- 1, 16- 2. The first sensor element 14- 1, 14- 2 is configured to initially detect an initial position of the second sensor element 16- 1, 16- 2 with respect to the first sensor element 14- 1, 14- 2 and to detect an offset of the second sensor element 16- 1, 16- 2 depending on this initial position. Such an offset arises when micromovements occur between the rings 2, 4 and the respective components 8, 10.The first sensor element 14- 1, 14- 2 may be, for example, a sensor head configured to detect a magnetically encoded sensor body, which may represent the second sensor element 16- 1, 16- 2. The sensor head or sensor reading head 14- 1, 14- 2 can have a linear resolution of approximately 1 μm, preferably of 1 μm or less, for example.The sensor head 14- 1, 14- 2 may have a cable connection that may be connected to a data acquisition system (not shown). Therefore, it is advantageous to attach the sensor head 14- 1, 14- 2 to the first or second component 8, 10. These components represent elements in comparison with the bearing rings 2, 4, from which a cable can be led away. The bearing rings 2, 4 are the creeping elements, i.e. the parts which can migrate with respect to the first and second components 8, 10. Such a data acquisition system can process the information acquired by the sensor head 14- 1, 14- 2 and in particular detect whether there is an offset of the sensor body 16- 1, 16- 2 with respect to its initial position.As already mentioned, the sensor head 14- 1, 14- 2 is fastened to the components 8, 10. For this purpose, as is shown for the component 10, for example, a recess 18 can be provided in which the sensor head 14- 1 can be arranged. Alternatively, as shown for the component 8, a sensor holder 22 may be provided on which the sensor head 14- 2 is arranged. In any case, the sensor head 14- 1, 14- 2 is fixed to the components 8, 10 so that it does not rotate with respect to these components 8, 10 but is stationary with respect thereto. As soon as one of the rings 2, 4 now performs a micro movement, the sensor head 14- 1, 14- 2 can detect this by detecting an offset of the sensor body 16- 1, 16- 2.In order to make this possible, the sensor body 16- 1, 16- 2 is arranged in each case on one of the rings 2, 4. As shown in FIG. 2, each of the rings 2, 4 may include a portion 20- 1, 20- 2 each including a groove 24- 1, 24- 2 in which the sensor body 16- 1, 16- 2 is disposed. The magnetically encoded sensor body 16- 1, 16- 2 can be present, for example, in the form of a band, as can also be seen in FIG. 3.The sections 20- 1, 20- 2 can be formed integrally with the rings 2, 4, but are located at the edge, in particular outside the load-bearing regions, such that the grooves 24- 1, 24- 2 have no influence on the load-bearing capacity of the rings 2, 4. However, it is also possible to provide the sensor bodies 16- 1, 16- 2 centrally or at any other desired position of the rings 2, 4. The portions 20- 1, 20- 2 may also be manufactured separately and fastened, e.g. screwed, to the rings 2, 4.As already mentioned above, the sensor body 16- 1, 16- 2 can be a magnetically encoded band which is arranged in the groove 24- 1, 24- 2. The band 16- 1, 16- 2 may be fixed in the groove 20- 1, 20- 2 by, for example, bonding. The fastening of the band 16- 1, 16- 2 should be resistant to temperature and lubricant, such as grease, oil, etc., since the bearing arrangement 1 can be completely flooded with lubricant, and the fastening of the band 16- 1, 16- 2 must also withstand such a load.As shown in FIG. 3, the band 16 may have open ends 28- 1, 28- 2. This facilitates assembly on the rings. However, since the joint edges 28- 1, 28- 2 risk of loosening, for example when passing over the sensor head 14- 1, 14- 2, a fastening element 26 is provided, as shown in FIG. 3. This fastening element is arranged in a depression 30 of the groove 24 and can be fastened in this depression 30 via fastening elements 32, 34. The open ends 28-1, 28-2 are clamped in this recess 30 by the fastener 26, in addition to the adhesive attachment in the groove 24. the fastener 26 has the advantage that there is a flat transition between the band 16 and the fastener 26 for the sensor head 14-1, 14-2. Detachment of the tape 16 is also prevented. This type of fastening is possible for both the inner ring 2 and the outer ring 4.In summary, the bearing arrangement proposed here provides a possibility of detecting creep effects in real time during the operation of the bearing arrangement. In this way, it is possible to react in good time by corresponding measures before damage occurs to the elements of the bearing arrangement.List of reference characters1 Bearing arrangement 2 Inner ring 4 Outer ring 6 Rolling bodies 8 Shaft / first component 10 Housing / second component 12- 1, 12- 2 Sensor 14- 1, 14- 2 Sensor head / first sensor element 16, 16- 1, 16- 2 Magnetically encoded sensor body / second sensor element 18 Cutout 20- 1, 20- 2 Ring section 22 Sensor holder 24, 24- 1, 24- 2 Groove 26 Fastening element 28- 1, 28- 2 Open ends 30 Depression 32 Fixing element 34 Corresponding fixing element R Direction of rotation of the shaft

Claims

Bearing arrangement (1) having an inner ring (2) and an outer ring (4) which are rotatable relative to one another, wherein the inner ring (2) is arranged on a first component (8) and the outer ring (4) is arranged in a second component (10), characterized in that the bearing arrangement (1) comprises a sensor for detecting micromovements of the inner ring (2) with respect to the first component (8) and / or micromovements of the outer ring (4) with respect to the second component (10), wherein the sensor (12-1, 12-2) comprises at least one first and at least one second sensor element (14-1, 14-2, 16-1, 16-2), wherein the first sensor element (14-1, 14-2) is arranged on the first component (8) and / or the second component (10) and wherein the second sensor element (16-1, 16-2) is arranged on the inner ring (2) and / or the outer ring (4), wherein the first sensor element (14-1, 14-2) is configured to detect an offset of the second sensor element (16-1, 16-2) with respect to the first sensor element (14-1, 14-2).Bearing arrangement according to claim 1, wherein the first sensor element (14-1, 14-2) is configured to detect the offset of the second sensor element (16-1, 16-2) with respect to the first sensor element (14-1, 14-2) in the rotational direction (R) and / or counter to the rotational direction (R) of the bearing arrangement (1) starting from an initial position.Bearing arrangement according to Claim 1 or 23, wherein the inner ring (2) and / or the outer ring (4) have a groove (24, 24-1, 24-2) in which the second sensor element (16-1, 16-2) is arranged, wherein the groove (24, 24-1, 24-2) faces the first sensor element (14-1, 14-2).Bearing arrangement according to one of the preceding claims, wherein the first component (8) and / or the second component (10) have a cutout (18), in which the first sensor element (14-1, 14-2) is arranged.Bearing arrangement according to one of the preceding claims, wherein the first component (8) and / or the second component (10) have a holding device (22), to which the first sensor element (14-1, 14-2) is fastened,Bearing arrangement according to one of the preceding claims, wherein the first sensor element (14-1, 14-2) is a sensor head and wherein the second sensor element (16-1, 16-2) is a magnetically encoded sensor body, wherein the sensor head (14-1, 14-2) is arranged facing the sensor body (16-1, 16-2).Bearing arrangement according to one of the preceding claims, wherein the magnetically encoded sensor body (16-1, 16-2) is a magnetically encoded band, wherein the band (16-1, 16-2) is arranged around the outer circumference of the outer ring (4) and / or around the outer circumference of the inner ring (2).The bearing arrangement according to claim 7, wherein the band (16-1, 16-2) is an open ring, and wherein the bearing arrangement (1) comprises a fastening element (26) configured to connect the two ends (28-1, 28-2) of the band (16-1, 16-2).Bearing arrangement according to claim 8, wherein the fastening element (26) is configured such that it forms a flat transition with the band (16-1, 16-2) with respect to the first sensor element (14-1, 14-2).Bearing arrangement according to claim 8 or 9, wherein the fastening element (26) is configured to secure the two ends (28-1, 28-2) of the band (16-1, 16-2) on a side of the fastening element (26) which is remote from the first sensor element (14-1, 14-2).Bearing arrangement according to one of Claims 8 to 10, wherein the sensor (12-1, 12-2) has two first sensor elements (14-1, 14-2) which are arranged with respect to one another at a distance in the circumferential direction which is greater than the extent of the fastening element (26) in the circumferential direction.

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