DE10324924A1 - Sleeve bearing with spherical or cylindrical baring surfaces has sensor attached to first bearing ring to detect measurement parameter dependent on distance of sensor from second bearing surface - Google Patents

Abstract

The device has a first bearing ring (1) with a first bearing surface (4), a second bearing ring (2) with second bearing surface (5), both bearing surfaces being spherical or cylindrical, and a sleeve bellows (3) between the bearing surfaces attached to one of the rings. At least one sensor (8) is attached to the first bearing ring to detect a measurement parameter dependent on the distance of the sensor from the second bearing surface. An independent claim is also included for the following: (a) a method of determining the state of wear of a sleeve bearing.

Description

The The invention relates to a plain bearing with a spherical or cylindrical design Storage areas. Farther The invention relates to a method for determining the wear of a Plain lining of a plain bearing with spherical or cylindrical design storage areas and / or a load taken up by such a plain bearing.

bearings with spherical or cylindrical bearing surfaces are already diverse known and are usually characterized in that between made of a hard and wear-resistant material storage areas a sliding surface with good sliding properties is arranged, the usually made of a softer material than the bearing surfaces and during the life of the plain bearing is subject to wear. Through this Wear change both the settings of the plain bearing, such as the Internal clearance, as well as the sliding properties. This can lead to the plain bearing specified minimum requirements over time no longer met and therefore becomes unusable and must be replaced. Because plain bearings frequently are made in a closed construction, is the sliding surface usually not accessible or at best only to a limited extent, so that a reliable Assessment of the condition of the sliding surface without at least one partially Disassembly is generally not possible is.

In this context, it is from the DE 201 04 695 U1 already known to enable a determination of the condition of wear plates, in particular for roll stands of a rolling mill, by equipping the wear plates with measuring bores which can be measured by means of a measuring device. Alternatively, it is proposed in this document to install one or more transducers in each case for a distance measurement in the wear plates. Furthermore, sensors for pressure measurement and sensors for acceleration measurement can be installed in the wear plates. The wear, the load condition and the acceleration of the respective wear plate can then be determined with the aid of the respective transducers.

at the wear plates is given the relatively large Thickness dimensions the insertion of measuring holes or the installation of measuring sensors possible without any problems. Given the in the Usually much thinner sliding coatings However, this procedure is not applicable to spherical plain bearings or cylindrical bearing surfaces can be transferred.

The Invention is based on the task of determining the current wear state of the sliding pads for plain bearings with spherical or cylindrical bearing surfaces to facilitate.

This The object is achieved by the combination of features of claim 1.

The Slide bearing according to the invention has a first bearing ring with a first bearing surface and a second bearing ring with a second bearing surface. The first storage area and the second storage area are spherical or cylindrical and are formed by a sliding coating, between the first storage area and the second storage area is arranged and attached to one of the two bearing rings, kept at a distance from each other. The peculiarity of the plain bearing according to the invention consists in that at least one sensor is attached to the first bearing ring is for the acquisition of a measurand that depends on the distance of the sensor from the second bearing surface.

The Invention has the advantage that in such a case equipped Plain bearings at any time without large Effort of wear and tear of the plain lining and / or the load absorbed by the plain bearing are. In particular, there is the possibility of the state of wear and / or the load continuously to monitor. So that can timely maintenance measures be initiated, compliance with specified operating conditions monitored be or measurement data for a specific application can be determined.

In a preferred embodiment the sensor is arranged in a recess in the first bearing ring. The Extension is preferably open towards the first bearing surface. That way the sensor can be integrated into the first bearing ring, so no changes must be carried out on the installation environment of the plain bearing. ever according to spatial Expansion of the sensor and according to the available measuring range can vary the sensor also extend into the sliding surface. This can on the one hand, the recess in the first bearing ring is made smaller and on the other hand can be a sensor with a smaller measuring range be used.

If one if possible high reliability achieved , it is advantageous to use at least one of the sensors as Reserve for takeover the function of a failed sensor. This is guaranteed that measured values are still available even after a sensor failure.

The The sliding lining is preferably attached to the first bearing ring, so that the sliding surface and the sensor do not move relative to each other.

With the inventive method become the state of wear of a plain lining between two bearing rings of a plain bearing with spherical or cylindrical bearing surfaces is arranged, and / or the load absorbed by such a plain bearing. The method according to the invention is characterized by the fact that a sensor signal is evaluated, that depends on the distance between the two bearing surfaces and is generated by at least one sensor on one of the two Bearing rings is attached.

With the inventive method it is possible, one and the same sensor both for determining the state of wear of the plain lining as well as the load absorbed by the plain bearing use.

In a preferred embodiment the state of wear of the plain lining and / or the load absorbed by the plain bearing in one Installation position of the plain bearing determined, in which the sensor in a Main load zone or in a relieved zone is arranged. This The advantage of geometry is that only one sensor is required and that the evaluation of the sensor signal is relatively simple. The sensor signal used to determine the state of wear can under a defined load state, preferably with negligible Load on the plain bearing. That way that the sensor signal is not influenced by a stress-induced deformation of the sliding surface becomes.

The Load received by the plain bearing can be made from a sensor signal for a negligible Load or a value derived therefrom and a sensor signal for the current load can be determined. That way the influence the state of wear of the sliding lining can be deducted from the sensor signal.

The Determination of the load absorbed by the plain bearing can be based on of the deflection behavior of the sliding surface. By compression of the sliding surface, the load is converted into a distance and is therefore relatively easy to measure. To get the most precise measurement results possible it is beneficial if for the plain bearing in new condition under a defined load condition, preferably with negligible Load on the plain bearing, a sensor signal is determined and as Reference signal is saved. The reference signal can then at the later Determination of the state of wear of the Plain lining and / or the load absorbed by the plain bearing is taken into account become.

The In the following, the invention is illustrated by means of the drawing Exemplary embodiments explained in more detail.

It demonstrate:

1 an embodiment of the plain bearing according to the invention in a sectional view,

2 . 3 . 4 and 5 this in 1 Illustrated embodiment of the plain bearing according to the invention for different load and wear conditions, each in a schematic sectional view.

1 shows an embodiment of the plain bearing according to the invention in a sectional view. The plain bearing has an outer ring 1 , an inner ring 2 and a sliding surface 3 on that radially between the outer ring 1 and the inner ring 2 is arranged. The sliding surface lies with its outer radial surface on a spherically designed outer bearing surface 4 the outer ring 1 on and is with the outer ring 1 firmly connected. The sliding surface lies with its inner radial surface 3 on a spherical inner bearing surface 5 of the inner ring 2 and is on this inner bearing surface 5 slidable. The inner ring 1 and the outer ring 2 are usually made of steel. The sliding surface 3 can, however, consist of a plastic material, for example.

The outer ring 1 has an axial bore 6 based on an axial end face 7 the outer ring 1 inside the outer ring 1 extends. In the axial center of the outer ring 1 is a sensor 8th in the axial bore 6 used. The sensor 8th penetrates the outer bearing surface 4 radially inwards and protrudes into a recess provided for this purpose 9 of the sliding surface 3 into it. In addition to the recess 9 shows the sliding surface 3 on its inner radial surface in the area of the recess 9 a trough-shaped depression 10 on. The recess 9 and the deepening 10 of the sliding surface 3 are not absolutely necessary and can, if the sensor is designed accordingly 8th and, depending on the overall geometry, can also be omitted. The sensor 8th is over a cable 11 with one in the area of the axial end face 7 in the axial bore 6 recessed plug 12 connected.

The outer ring is in the installed state of the plain bearing 1 for example fixed in a housing and the inner ring 2 takes a rotatable and tiltable shaft and thus moves relative to the outer ring 1 , With this movement there is a sliding movement between the inner radial surface of the sliding lining 3 and the inner storage area 5 of the inner ring 2 associated. Over time, this sliding movement leads to wear of the sliding surface 3 , which results in a reduced thickness of the sliding surface 3 manifests. This in turn has the consequence that the sliding surface 3 no longer completely on the inner bearing surface 5 is present and the slide bearing has an increasing amount of play with increasing wear. In other words, the two storage areas 4 and 5 are due to the sliding surface 3 no longer kept at a constant distance, but the distance varies between a minimum value d1 at which the sliding surface 3 on the inner bearing surface 5 is present and a maximum distance d2, which is set on the side diametrically opposite the minimum distance d1. The minimum distance d1 or the maximum distance d2 between the two bearing surfaces 4 and 5 is with the sensor 8th detected, so that with the help of the sensor signal the current state of wear of the sliding lining 3 can be determined.

Because the material of the sliding surface 3 generally yields elastically when exposed to pressure, the load situation must be taken into account when evaluating the sensor signals. There is also the option of using the same sensor 8th to determine the load absorbed by the plain bearing under certain conditions. Details on determining the state of wear and determining the load using the sensor 8th are described below. For this purpose, the 2 . 3 . 4 and 5 First explains how different load conditions and different wear conditions affect the relative position of the outer bearing surface 4 and the inner storage area 5 to each other, ultimately that of the sensor 8th generated signal depends on impact.

The 2 . 3 . 4 and 5 show that in 1 Illustrated embodiment of the plain bearing according to the invention for different load and wear conditions, each in a schematic sectional view. In order to make the differences between these states clear, the plain bearing is shown in full. There is also a wave 13 marked by the inner ring 2 is picked up and via which a load is possibly introduced into the plain bearing.

The in 2 condition shown is characterized in that on the sliding surface 3 there is still no wear and the plain bearing does not accept any significant load. The dead weight of the plain bearing is viewed as an arbitrarily small load L, which is vertically down on the shaft 13 acts and is represented by an arrow. Again 2 can be seen, is the sliding surface 3 with its inner radial surface over the entire bearing surface 5 of the inner ring 2 on, ie the plain bearing has no play. It is also the distance between the outer bearing surface 4 and the inner storage area 5 everywhere the same size, so there is in particular the minimum distance d1, which is in the in 2 shown conditions in the lower region of the plain bearing, is equal to the maximum distance d2 in the upper region of the plain bearing. This means that the sensor 8th in the assembly position represented by a solid line in the lower region of the plain bearing and in the assembly position represented by a broken line in the upper region of the plain bearing provides the same sensor signals.

In 3 shows the sliding surface 3 also no wear. However, the plain bearing is in contrast to 2 loaded. The load L is in the representation of the 3 in a vertical downward direction in the lower area of the inner ring 2 initiated. Such a load on the plain bearing arises, for example, at a standstill from the weight of one on the shaft 13 assembled machine part. The load on the inner ring 2 has the consequence that the sliding surface 3 in the contaminated zone, ie in the representation of the 3 in the lower area, and thereby the minimum distance d1 between the outer bearing surface 4 and the inner storage area 5 compared to 2 is reduced. As the minimum distance d1 in the loaded zone decreases, the maximum distance d2 between the outer bearing surface increases 4 and the inner storage area 5 in the relieved zone, ie in the representation of the 3 in the upper area of the plain bearing. This can cause the compression of the sliding surface caused by the load 3 be determined both in the loaded zone and in the unloaded zone. The sensor can thus be arranged either in the loaded or in the relieved zone and detects one in each case compared with 2 same amount of change in the distance between the storage areas 4 and 5 ,

In 4 a state is shown in which the plain bearing is not loaded, but already a wear on the plain lining 3 is present. This wear manifests itself in the fact that the radial dimensions of the sliding surface 3 compared to 2 are reduced. However, these radial dimensions are the same everywhere, assuming even wear. In particular, the radial dimensions are shown in the 4 the same in the upper and lower area of the plain bearing. Nevertheless, the minimum distance is d1 between the two bearing surfaces 4 and 5 in the lower area of the plain bearing significantly less than the maximum distance d2 between the two bearing surfaces 4 and 5 in the upper area. This results from the fact that the inner ring 2 as a result of his own weight in the lower area of the plain bearing with its inner bearing surface 5 on the sliding surface 3 abuts and thus in the upper area a radial space between the inner bearing surface 5 and the sliding surface 3 arises. As in 3 can also at 4 the distance between the two bearing surfaces 4 and 5 be measured in both the lower and the upper range. Because the distance from the wear condition of the sliding surface 3 depends on, this state of wear can be currently determined from the sensor signals. When carrying out the measurement, however, it should be noted that a change in the minimum distance d1 or the maximum distance d2 between the two bearing surfaces 4 and 5 with the help of the sensor 8th can be determined, the sensor 8th however, beyond that, it cannot detect the cause of the change in distances d1 and d2. It is therefore necessary to carry out the conditions for the generation of the sensor signals and the evaluation of the sensor signals in such a way that conclusions can actually be drawn about the state of wear of the sliding lining 3 possible are. How to proceed in detail is explained below.

5 finally shows a situation where the sliding surface 3 is already subject to a certain amount of wear and a load L also acts on the slide bearing. It is therefore a combination of the in the 3 and 4 represented states. The result is the sliding surface 3 in the loaded zone with the same acting load L as in 3 shown to a smaller radial extent than in 3 compressed, so that the minimum distance d1 between the two bearing surfaces 4 and 5 is correspondingly less than that in 3 shown minimum distance d1. Associated with this is the maximum distance d2 between the two bearing surfaces 4 and 5 in the relieved zone larger than in 3 , That from the sensor 8th Output signal is therefore a measure of the sum of the wear caused by the sliding lining 3 and by loading the inner ring 2 compared to a new, unloaded slide bearing change in the minimum distance d1 or the maximum distance d2. As will be explained in more detail below, it is possible within the scope of the method according to the invention, despite the overlapping of the two effects from the sensor signal, to selectively determine the state of wear of the sliding coating 3 or to determine the load L acting on the plain bearing.

To determine the state of wear of the sliding surface 3 the procedure is as follows:
The plain bearing is supported by the shaft 13 or other measures brought into an unloaded state. Strictly speaking, the sliding lining is determined by the weight of the inner ring 2 loaded. The stress caused by this is so low, however, that there is no significant compression of the sliding surface 3 results. In this unloaded state, the minimum distance d1 or the maximum distance d2 between the two bearing surfaces 4 and 5 with the help of the sensor 8th determined. The value determined in this way can be compared, for example, with a reference value for the sliding coating 3 the state of wear of the sliding lining when not worn 3 be determined. In order to obtain particularly precise results, the reference value can be specified individually for the plain bearing by taking a measurement with the plain bearing in new condition under otherwise identical conditions and documenting the sensor signal determined in this way as a reference value. In principle, it is also possible to at least approximately determine the state of wear under load. In this case, the reference value is created beforehand with an identical load.

In order to determine the load currently acting on the bearing, it is necessary to determine the wear condition of the sliding lining 3 to eliminate the measurement result. This can be done, for example, with the sensor 8th a measurement is carried out on the unloaded plain bearing. Then a second measurement is carried out under otherwise identical conditions on the loaded plain bearing. The difference in the distance d1 and d2 between the two bearing surfaces resulting from these two measurements 4 and 5 is caused exclusively by the load on the plain bearing and is therefore a measure of the load L acting on the plain bearing. This means that according to the invention with one and the same sensor 8th both the wear condition of the sliding surface 3 as well as the load L acting on the slide bearing can be determined.

In principle, it is also possible to use the sensor 8th neither in the loaded zone nor in the unloaded zone, but in an intermediate position and then carry out the measurements described above. In order to achieve sufficient measuring accuracy in this case, too, it is recommended to use several sensors 8th to install, preferably at least three sensors 8th be used. In view of the known geometry of the plain bearing, the sensor signals generated by these sensors can be used to calculate back to the conditions in the loaded or unloaded zone, so that the evaluation is otherwise possible in the manner already described.

If multiple sensors 8th are used, it is also possible to carry out the method according to the invention even if one or more of these sensors 8th has failed. In this case, the sensors are kept in reserve 8th switched.

The information obtained with the method according to the invention about the state of wear of the sliding lining 3 and / or the load acting on the slide bearing can be further processed with different objectives. For example, it is possible to feed these values into a monitoring system that registers an excessive wear condition or an excessive load L that may occur and then initiates appropriate maintenance measures or an exchange of the plain bearing. It is also possible to only register these measured values in order to determine information about actual load or wear conditions for a specific application.

The slide bearing according to the invention can, in a modification of the exemplary embodiments described, instead of the spherically designed bearing surfaces 4 and 5 also cylindrical bearing surface 4 and 5 exhibit.

Depending on the design of the plain bearing according to the invention, the sensor can 8th For example, be designed as an inductive or a capacitive measuring system.

1

outer ring

2

inner ring

3

sliding lining

4

outer storage area

5

inner storage area

6

axial bore

7

axial end face

8th

sensor

9

recess

10

deepening

11

electric wire

12

plug

13

wave

Claims (12)

Plain bearing with a first bearing ring ( 1 ), which has a first storage area ( 4 ) and a second bearing ring ( 2 ), which has a second storage area ( 5 ), the first bearing surface ( 4 ) and the second storage area ( 5 ) are each spherical or cylindrical and are supported by a sliding coating ( 3 ) between the first storage area ( 4 ) and second storage area ( 5 ) is arranged and on one of the two bearing rings ( 1 . 2 ) is held at a distance from one another, characterized in that on the first bearing ring ( 1 ) at least one sensor ( 8th ) is attached to the acquisition of a measured variable that depends on the distance of the sensor ( 8th ) depends on the second storage area. Slide bearing according to claim 1, characterized in that the sensor ( 8th ) in a recess ( 6 ) in the first bearing ring ( 1 ) is arranged. Slide bearing according to claim 2, characterized in that the recess ( 6 ) to the first storage area ( 4 ) is open. Plain bearing according to one of the preceding claims, characterized in that the sensor ( 8th ) in the sliding surface ( 3 ) extends into it. Slide bearing according to one of the preceding claims, characterized in that at least one of the sensors ( 8th ) as a reserve for taking over the function of a failed sensor ( 8th ) is provided. Plain bearing according to one of the preceding claims, characterized in that the sliding lining ( 3 ) on the first bearing ring ( 1 ) is attached. Procedure for determining the state of wear of a sliding surface ( 3 ) between two bearing rings ( 1 . 2 ) a plain bearing with spherical or cylindrical bearing surfaces ( 4 . 5 ) is arranged, and / or a load (L) picked up by such a plain bearing, characterized in that a sensor signal is evaluated which depends on the distance between the two bearing surfaces ( 4 . 5 ) depends on each other and on at least one sensor ( 8th ) is generated on one of the two bearing rings ( 1 . 2 ) is attached. A method according to claim 7, characterized in that the state of wear of the sliding lining ( 3 ) and / or the load (L) absorbed by the plain bearing can be determined in an installed position of the plain bearing in which the sensor ( 8th ) is located in a main load zone or in a relieved zone. Method according to one of claims 7 or 8, characterized in that that the sensor signal used to determine the state of wear under a defined load state, preferably with negligible Load on the plain bearing is determined. Method according to one of claims 7 to 9, characterized in that that the load (L) received by the plain bearing from a sensor signal for a negligible Load or a value derived therefrom and a sensor signal for the current load is determined. Method according to one of claims 7 to 10, characterized in that the determination of the load (L) absorbed by the plain bearing on the basis of the deflection behavior of the plain lining ( 3 ) he follows. Method according to one of Claims 7 to 11, characterized in that a sensor signal is determined for the plain bearing in new condition under a defined load condition, preferably with negligible load on the plain bearing, and is stored as a reference signal which is used to determine the state of wear of the plain lining ( 3 ) and / or the load (L) absorbed by the plain bearing is taken into account.