DE102014200712A1 - Hydrodynamic plain bearing and method for operating state monitoring of a hydrodynamic plain bearing - Google Patents

Abstract

A hydrodynamic sliding bearing (1) for supporting a shaft (9) is disclosed which comprises at least one sliding element (5) with a sliding surface (6). According to the invention, at least one sensor (11), which is constructed from a functional layer system (13), is applied to at least one sliding element (5). A signal pick-off element (15) of the sensor (11) is then connected via at least one electrical line (17). the measured values are passed to an evaluation unit (19). Subsequently, in the evaluation unit (19), the measured values are evaluated and from this during operation of the hydrodynamic sliding bearing (1) statements about the operating state of the hydrodynamic sliding bearing (1) are derived with regard to loads, deformation and temperature.

Description

The present invention relates to a hydrodynamic sliding bearing for supporting a shaft which comprises at least one sliding element with a sliding surface. Furthermore, the present invention relates to a method for operating state monitoring of a hydrodynamic sliding bearing.

Background of the invention

General applications of classical hydrodynamics are large electric motors and generators (in the megawatt range), turbines, internal combustion engines for automobiles, commercial vehicles, trucks, ships and railways as well as for large industrial areas. However, if friction between relatively moving elements (in particular in the inlet and outlet) is to be reduced in a bearing, hydrostatic bearings are frequently used, for example during start-up and shut-down processes, when starting under load or when operating and boundary conditions occur.

Such a hydrostatic sliding bearing has an active lubricant circuit, which is maintained by an external pump and which is guided through the bearing gap between the relatively moving elements. In the bearing gap, a thin hydrostatic support film builds up, which reduces the friction between relatively moving elements. To prevent damage to hydrostatic plain bearings, systems are used that detect abnormal bearing conditions and initiate corresponding safety measures against damage and bearing failures. Metrology then sensors for the measurement of temperatures in the narrowing columns are known. Furthermore, it is known from the field of experimental equipment that lubricant film thickness heights are used by hydrostatic and by the use of capacitive distance measurement.

But even with hydrodynamic plain bearings, in which the lubricating film is produced only by the movement of the plain bearing, operating state variables are already measured. Thus, for example, the temperature measurement takes place in at least one sliding element of the hydrodynamic sliding bearing, such. B. in a bearing shell near a Gleitflächenzone. Furthermore, the measurement of a wave displacement in different directions as an indicator of the prevalence of hydrodynamics, ie the presence of a separating lubricating film, is common. However, the sensor system to be used for this is often introduced quite laboriously, such as in small holes in the sliding elements, such as in a bearing shell or in a tilting segment of a tilting pad bearing, in which a temperature sensor (eg: a PT100) is inserted. The challenge here is to get close to the sliding surface, but not push through the hole or weaken this spot near the hole. Previously used Wellenverlagerungssensoriken be directed from the outside to the shaft. Often the sensors then sit outside of a housing of a hydrodynamic plain bearing. In this case, cables often look out and the sensor / evaluation technology used is also very expensive. In order to be able to reliably measure deformations, strain gauges are used which have to be arranged and glued in a complicated manner. The place of sticking is always very sensitive (eg loosening of the adhesive bond under the influence of centrifugal force). In addition, these strain gauges always stand out and represent potential danger spots.

An object of the present invention is therefore to provide a hydrodynamic sliding bearing which collects in operation measurement data on the state of the hydrodynamic sliding bearing and thus allows the monitoring of loads and load distribution in the hydrodynamic sliding bearing in a simple manner.

This object is achieved by a hydrodynamic sliding bearing comprising the features in claim 1.

Another object of the present invention is to provide a simple method of operating condition monitoring of a hydrodynamic journal bearing which continuously measures bearing loads and thus monitors the journal bearing condition.

This object is achieved by a method for operating state monitoring of a hydrodynamic sliding bearing comprising the features in claim 10.

The hydrodynamic sliding bearing according to the invention for supporting a shaft comprises at least one sliding element with a sliding surface

In particular, the hydrodynamic sliding bearing according to the invention is a tilting pad bearing, such as, for example, an axial tilting pad bearing, a radial tilting pad bearing or a combination of an axial tilting pad bearing and a radial tilting pad bearing. Likewise, however, it is also conceivable that the hydrodynamic sliding bearing according to the invention is designed as a fixed-segment bearing or a single-surface sliding bearing. New potential and promising application for such hydrodynamic bearings are wind turbines and marine power and flow power plants, where these bearings are used in the main rotor bearing.

Since with hydrodynamic plain bearings not as in the case of rolling bearings a fatigue theory can be applied in which a full or mixed friction is assumed and the material properties, such as strength, etc., the bearing components are known, these plain bearings must be designed with a minimum lubricant film thickness, thus Machining inaccuracies (concentricity, roundness, ...) and surface qualities (Ra, Rz, Rpk, ...) can be compared. It is then possible to derive statements on the operating status of a hydrodynamic plain bearing. Influence parameters on the resulting operating clearance and the performance of the hydrodynamic sliding bearing in operation are temperature, local pressures in the contact area (wedge gap) and the lubricating film height.

According to the invention, at least one sensor, which is constructed from a functional layer system, is applied to the at least one sliding element. This functional layer system is characterized by the fact that the sliding element of the hydrodynamic plain bearing coated with only a few micrometers not only transfers forces but also detects and transmits physical quantities such as torques, forces, elongation or temperature. Thus, the bearing loads can be continuously measured and monitored.

In order to be able to pick up measuring signals, each sensor comprises, in addition to a strain-sensitive measuring layer, which is the functional layer system, at least one signal pick-off element. In this case, the deformation-sensitive measuring layer can in particular consist of a metallic material or a semiconductor material. In particular, the strain-sensitive measuring layer can consist of a nickel alloy or of titanium oxynitride.

This formation-sensitive measuring layer deforms during operation in accordance with a deformation of the at least one sliding element. Ie. a deformation of the sliding element is "transferred" to the formation-sensitive measuring layer. The strain-sensitive measuring layer is thus, depending on the deformation, positively (stretch) or negative (compression) stretched.

Also, the at least one sliding element of the hydrodynamic sliding bearing according to the invention can provide a protective layer. This protective layer is then applied to the formation-sensitive measurement layer and essentially serves to protect the formation-sensitive measurement layer from contamination, corrosion and mechanical damage, as well as from unwanted contact of the formation-sensitive measurement layer with conductive material. However, it should be noted that this formation-sensitive measuring layer does not necessarily have to provide a protective layer. This protective layer is therefore optional to apply in special applications.

Furthermore, each sliding element with at least one sensor has an electrical line in order to conduct measurement data from the at least one signal pickup element of each sensor to an evaluation unit.

In particular, in the case of the invention, each sensor is designed such that the strain-sensitive measuring layer has at least one turn. Preferably, however, the strain-sensitive measuring layer has a plurality of turns.

In the case of the hydrodynamic sliding bearing according to the invention, at least the strain-sensitive measuring layer of a sensor is applied to the sliding element on an upper side, a lower side or on an end face, which interacts with a friction partner. The at least one signal pick-up element of a sensor is applied on an upper side, a lower side or on at least one of four end faces of the sliding element.

Consequently, various embodiments of the deformation-sensitive measuring layer to be applied and of the at least one signal pick-up element of a sensor are conceivable. Thus, in one embodiment, the strain-sensitive measuring layer and the signal pick-up element of a sensor on the top, bottom or end face applied, however, gebeuteten in another embodiment of the invention, the strain-sensitive measuring layer on the top or bottom and the signal pick-off element on one of the four end faces of the sliding element is.

In a preferred embodiment of the hydrodynamic sliding bearing according to the invention, the sliding element is constructed from a plurality of tilting segments, as for example in the case of an axial tilting pad bearing. In this case, the axial tilting pad bearing comprises a carrier disk with a plurality of tilting segments with this functional layer system, which are arranged on the radius of the carrier disk. In this case, then, the support disk is fixedly connected to a housing of the hydrodynamic axial Kippsegmentlagers. Further, it is then envisaged that a wave washer which is connected to a shaft torsionally rigid (alternatively provided by the geometry of the shaft itself, so that no wave washer is needed) and moves relative to the carrier disk and the tilting segments.

In general, it should therefore be noted that this functional layer system is applied to at least one sliding element (bearing shell, tilting segment) of a hydrodynamic sliding bearing so that, although it is the preforming of the sliding element absorbs, but not as previously known and common, sitting in direct sliding contact, where it is worn and destroyed. Since tilting segments or even areas of fixed-segment bearings are deformed by a load on the counter-rotor, the sensor does not necessarily have to be in contact. For this reason, a preferred embodiment, the sensor according to the invention to be applied to an underside of a tilting segment or on the end faces (axial surfaces) of a radial bearing. There, the deformation can then be recorded without being in direct sliding contact (a direct sliding contact between the sliding member and the wave washer is formed, for example, during start-up, when there is no separating lubricating film).

The method according to the invention for operating state monitoring of the above-described hydrodynamic sliding bearing is characterized by the following steps. By at least one sensor, which is constructed from a functional layer system and is applied to at least one sliding element of the hydrodynamic sliding bearing, measured values are generated via the state of the hydrodynamic sliding bearing. From a signal pick-off element of the sensor, the measured values are then passed to an evaluation unit via at least one electrical line. In the evaluation unit, the measured values are evaluated and derived therefrom in the operation of the hydrodynamic sliding bearing statements about the operating state of the hydrodynamic plain bearing with regard to loads, deformation and temperature.

Basically, two measurement tasks are solved with the invention. On the one hand allows a 3D sensor at least one sliding element, preferably a plurality of tilting segments, a determination of the strain in different directions and at different points of the sliding element or the Kippsegmente and on the other allows a sensor of the contact pressure and the contact pressure of the sliding element or the Tilting segments, which result from the pressure build-up formed in the narrowing lubricating gap, the detection of Gleitelement- or Kippsegmentbelastung.

In particular, the 3D sensor serves to draw conclusions about the lubricant pressure and possibly the lubrication gaps. It should also be noted that the functional layer system offers no additional wear protection. Thus, the sensors on the slider or tipping segments must not be contacted or over-slid, e.g. at startup. The sliding element or the tilting segments may only experience compressive forces. As a result, the functional layer system should not be applied to locations which are in contact with the mating partner when the hydrodynamic sliding bearing is at a standstill (ie not on latching surfaces). The application of the strain-sensitive measuring layer, that is to say the functional layer system, therefore lends itself to an underside of the sliding element or tilting segment, wherein application of the functional layer system on an upper side of the sliding element or tilting segment is also possible with the above restriction.

The sensor for detecting Gleitelement- or Kippsegmentbelastung serves to draw conclusions about the load on the hydrodynamic slide bearing as a whole and the detection of Wellenverkippungen. This measurement task can be combined with the above prescribed measurement task as well as provide the use of a piezoresistive layer system on its own.

The invention thus provides a sensor which has a high degree of integration, since it no longer represents a separate component and sits in the immediate vicinity of the sliding contact. By deformation, load and load distribution can be measured.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions in the figures do not always correspond to the actual size ratios, as some shapes are simplified and other shapes are shown enlarged in relation to other elements for ease of illustration. Showing:

1 a perspective view of a support disk of a hydrodynamic sliding bearing on which a sliding element in the form of a plurality of tilting segments is arranged;

2 a perspective view of a wave washer of the hydrodynamic sliding bearing, with the in 1 illustrated carrier disc and the tilting segments forms the hydrodynamic sliding bearing;

3 a perspective view of a tilting segment with a formed on a bottom of the tilting segment Kippsteg; and

4 to 10 various embodiments of at least one applied to a tilting sensor of the hydrodynamic sliding bearing according to the invention.

For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments are merely examples, such as Inventive hydrodynamic sliding bearing and the inventive method for operating state monitoring of a hydrodynamic sliding bearing can be configured and thus do not constitute a final limitation of the invention.

Although the following description refers to a sliding member constructed of a plurality of tilting segments and applied to an axial tilting pad bearing, radial tilting pad bearing or a combination of an axial tilting pad bearing and radial tilting pad bearing, this should not be construed as limiting the invention ,

1 shows a perspective view of a carrier disk 3 a hydrodynamic plain bearing 1 on which on a radius R a sliding element 5 with a sliding surface 6 in the form of a plurality of tilting segments 5 each with a sliding surface 6 is arranged. Here then is the carrier disk 3 connected stationarily with a housing, not shown here.

2 shows a perspective view of a wave washer 7 of the hydrodynamic plain bearing 1 , The wave washer 7 is with a wave 9 torsionally connected. The wave washer 7 forms with the in 1 illustrated carrier disk 3 and the tilting segments 5 the hydrodynamic plain bearing 1 , During operation, the wave washer moves 7 relative to the carrier disk 3 and the tilting segments 5 Other embodiments of the invention also are not wave washer 7 Provide, namely, when the shaft 9 a suitable geometry for the carrier disk 3 or for example also for a bearing shell.

3 shows a perspective view of a tilting segment 5 with one at a bottom 23 of the tilting segment 5 trained tilting bridge 27 standing on the carrier disk 3 when turning by means of in 2 represented wave 9 a tilting movement of the tilting segment 5 allows.

4 to 10 show various embodiments of at least one on a tilting segment 5 applied sensor 11 the hydrodynamic sliding bearing according to the invention 1 , The sensor 11 is according to the invention of a functional layer system 13 built up. There is every sensor 11 from a strain-sensitive measuring layer 13 , which is the functional layer system, and at least one signal tapping element 15 , In addition, each tilting segment 5 with at least one sensor 11 an electrical line 17 on. This is exemplary in 1 shown. This electrical line 17 serves to provide measurement data from the at least one signal tapping element 15 every sensor 11 to an evaluation unit 19 (see also 1 ). In the evaluation unit 19 the measured values are evaluated and from this during operation of the hydrodynamic plain bearing 1 Statements about the operating condition of the hydrodynamic plain bearing 1 with regard to derived from loads, load distribution (tilting) deformation and temperature.

At the in 4 illustrated embodiment are on the tilting segment 5 two sensors 11 applied. As mentioned earlier, each sensor exists 11 from the strain-sensitive measuring layer 13 , which is the functional layer system, and at least one signal tapping element 15 , The sensors shown here 11 are designed such that the strain-sensitive measuring layer 13 has several turns N. In particular, here is the strain-sensitive measuring layer 13 on a bottom 23 and two signal pickup elements 15 every sensor 11 on a face 25 of the tilting segment 5 applied.

In the in 5 shown embodiment, are on the tilting segment 5 six sensors 11 applied. Here is the deformation-sensitive measuring layer 13 all six sensors 11 on a top 21 of the tilting segment 5 applied, however, all Signalabgriffselemente 15 on all four faces 25 of the tilting segment 5 are applied distributed.

The tilting segment 5 in 6 has three sensors 11 on, where each strain-sensitive measuring layer 13 on the top 21 and each signal tapping element 15 on the face 25 of the tilting segment 5 is applied. At this end face 25 , it is the one with the in 2 Shaft shown as a friction partner 7 interacts. In this embodiment, each of the three strain-sensitive measurement layers 13 in contrast to the previously shown strain-sensitive measuring layers 13 only one turn N up.

In the in 7 illustrated embodiment, are on the tilting segment 5 two sensors 11 applied. Since the embodiment illustrated here, the attachment of the deformation-sensitive measuring layer 13 and the Signalabgriffselemente 15 of the 6 is the same, is waived on a new description at this point.

At the in 8th illustrated embodiment are on the tilting segment 5 four sensors 11 applied. Here is every deformation-sensitive measuring layer 13 as well as each of the two signal taps 15 every sensor 11 on the bottom 23 a tilting segment 5 applied.

The tilting segment 5 in 9 has two sensors 11 applied. The strain-sensitive measuring layer 13 every sensor 11 is on the top 21 of the tilting segment 5 applied. Both signal pickup elements 15 every sensor 11 are on the face 25 of the tilting segment 5 Applied to the wave washer 7 (S. 2 ) interacts as a friction partner.

In the in 10 illustrated embodiment are two sensors 11 including any strain sensitive sensing layer 13 as well as each signal tapping element 15 , on the face 25 of the tilting segment 5 is applied, with the wave washer 7 (S. 2 ) interacts as a friction partner.

By in the 4 to 10 various illustrated embodiments of the on a tilting segment 5 applied sensors 11 It goes without saying that many more embodiments are conceivable without having to explicitly list them.

LIST OF REFERENCE NUMBERS

1

 hydrodynamic plain bearing

3

 carrier disc

5

 Sliding element, tilting segment

6

 sliding surface

7

 Friction partner, wave washer

9

 wave

11

 sensor

13

 Measuring layer, functional layer system

15

 Signalabgriffselement

17

 electrical line

19

 Auswerteeinhei

21

 top

23

 bottom

25

 face

27

 tilting

R

 Radius of the carrier disk

N

 convolution

Claims (10)

Hydrodynamic plain bearing ( 1 ) for supporting a shaft ( 9 ), with at least one sliding element ( 5 ) with a sliding surface ( 6 ), characterized in that on the at least one sliding element ( 5 ) at least one sensor ( 11 ), which consists of a functional layer system ( 13 ) is constructed. Hydrodynamic plain bearing ( 1 ) according to claim 1, wherein each sensor ( 11 ) from a strain-sensitive measuring layer ( 13 ), which is the functional layer system, and at least one signal pickup element ( 15 ) consists. Hydrodynamic plain bearing ( 1 ) according to claim 1 or 2, wherein each sliding element ( 5 ) with at least one sensor ( 11 ) an electrical line ( 17 ) to receive measurement data from the at least one signal tapping element ( 15 ) of each sensor ( 11 ) to an evaluation unit ( 19 ). Hydrodynamic plain bearing ( 1 ) according to any one of the preceding claims, wherein each sensor ( 11 ) is configured such that the strain-sensitive measuring layer ( 13 ) has at least one turn (N). Hydrodynamic plain bearing ( 1 ) according to one of the preceding claims, wherein at least the strain-sensitive measuring layer ( 13 ) of a sensor ( 11 ) on a top side ( 21 ), a bottom ( 23 ) or on an end face ( 25 ) of the sliding element ( 5 ) is applied, which with a friction partner ( 7 ) cooperates. Hydrodynamic plain bearing ( 1 ) according to one of the preceding claims, wherein at least one signal tapping element ( 15 ) of a sensor ( 11 ) on a top side ( 21 ), a bottom ( 23 ) or on at least one of four end faces ( 25 ) of the sliding element ( 5 ). Hydrodynamic plain bearing ( 1 ) according to claim 5 or 6, wherein the strain-sensitive measuring layer ( 13 ) and the signal pickup element ( 15 ) of a sensor ( 11 ) on the top ( 23 ), Underside ( 23 ) or the face ( 25 ) of the sliding element ( 5 ) are applied. Hydrodynamic sliding layer ( 1 ) according to claim 6 or 7, wherein the strain-sensitive measuring layer ( 13 ) on the top ( 21 ) or the underside ( 23 ) and the signal pickup element ( 15 ) on one of the four end faces ( 25 ) of the sliding element ( 5 ). Hydrodynamic bearings ( 1 ) according to one of the preceding claims, wherein the sliding element consists of a plurality of tilting segments ( 5 ) is constructed. Method for operating state monitoring of a hydrodynamic sliding bearing ( 1 ) according to one of the preceding claims, characterized by the following steps, characterized in that at least one sensor ( 11 ), which consists of a functional layer system ( 13 ) and on at least one sliding element ( 5 ) of the hydrodynamic plain bearing ( 1 ), measurements on the state of the hydrodynamic plain bearing ( 1 ) be generated; that of a signal pickup element ( 15 ) of the sensor ( 11 ) via at least one electrical line ( 17 ) the measured values to an evaluation unit ( 19 ) and that in the evaluation unit ( 19 ) evaluated the measured values and from it in the operation of the hydrodynamic plain bearing ( 1 ) Statements about the operating condition of the hydrodynamic plain bearing ( 1 ) with regard to loads, deformation and temperature.

Images