Segmented plain bearing and method for operating a plain bearing

Abstract

The present invention relates to a segmented plain bearing (1), in particular in a wind turbine, comprising a plurality of plain bearing segments (3), wherein uncovered surface regions of a machine element (2) mounted by means of the plain bearing segments (3) are arranged in circumferential regions between the plain bearing segments (3), and wherein a contactlessly operating temperature measuring device (5, 6) is provided for monitoring the temperature of at least one of said surface regions.

Description

[0001] Segmented plain bearing and method for operating a plain bearing

[0002] The invention relates to a segmented plain bearing, i.e., a bearing comprising a plurality of plain bearing segments. Furthermore, the invention relates to a wind turbine with such a bearing. Furthermore, the invention relates to a method for operating a segmented plain bearing.

[0003] EP 2 762 735 A1 discloses a tilting-pad plain bearing with direct lubrication. Individual pads of the plain bearing form oil-conducting structures. The plain bearing according to EP 2 762 735 A1 is designed for machines operating at high speeds.

[0004] Another tilting-pad bearing is known, for example, from DE 34 14 910 A1. In this case, too, lubrication grooves are formed in the bearing segments. The design of the bearing according to DE 34 14 910 A1 is intended to take into account, in particular, effects resulting from bending vibrations of a supported shaft.

[0005] DE 33 32 357 C1 concerns a hydrostatic-hydrodynamic hybrid multi-sliding surface radial bearing. This bearing is designed to simultaneously achieve good vibration and stability properties by installing hydrostatic bearing pockets in the area of ​​the narrowest bearing cross-section.

[0006] A monitoring system for a hydrodynamic or hydrostatic plain bearing is disclosed in DE 10 2019 117 945 A1. The monitoring system comprises at least one acceleration sensor, which is to be arranged on the plain bearing, and an evaluation unit. The evaluation unit is capable of detecting insufficient lubrication or a break in the lubricating film based on data from the acceleration sensor. The invention is based on the object of further developing segmented plain bearings, in particular large-diameter bearings, compared to the prior art in such a way that particularly high operational reliability can be achieved even under changing operating conditions.

[0007] This object is achieved according to the invention by a segmented plain bearing having the features of claim 1. The segmented plain bearing is particularly suitable for use in a wind turbine according to claim 8. The object is also achieved by a method for operating a segmented plain bearing designed according to claim 9. The embodiments and advantages of the invention explained below in connection with the operating method also apply mutatis mutandis to the devices, i.e., the plain bearing and the wind turbine equipped therewith, and vice versa.

[0008] The segmented plain bearing according to the application comprises a plurality of plain bearing segments, wherein uncovered surface areas of a machine element, in particular a shaft, mounted by means of the plain bearing segments are arranged in circumferential areas between the plain bearing segments, and wherein a non-contact temperature measuring device is provided for monitoring the temperature of at least one of these surface areas.

[0009] The plain bearing is specifically designed as a hydrodynamic plain bearing. Hydrodynamic plain bearings are generally characterized by low friction and a long service life, as long as boundary or mixed friction is avoided. Avoiding such conditions, which can lead to excessive wear, is achieved to an excellent degree by the temperature monitoring system as per the application.

[0010] Due to the rotation of the shaft, which is supported by the plain bearing, new surface areas of the shaft are constantly being detected by the non-contact sensor system used for temperature monitoring. This applies regardless of whether the plain bearing is designed as an axial bearing, a radial bearing, or another type of bearing that absorbs both axial and radial forces. Another advantage in all cases is the fact that power supplies to rotating parts can be dispensed with. Furthermore, it is worth mentioning that no measurement has to be taken through sliding linings, and therefore a fast response of the temperature measurement provides a good basis for rapid reactions to deviations from intended operation.

[0011] If the segmented plain bearing is designed as a radial bearing, the individual segments intended to support a shaft can themselves be supported by plain bearings in the axial direction of the respective segments, i.e., supported by axial plain bearings. The axial plain bearings can be spherical plain bearings, i.e., bearings with multiple degrees of freedom, or tilting bearings, i.e., bearings with exactly one degree of freedom.

[0012] At least one pyrometer can be provided to measure the surface temperature in a contiguous, uncovered surface area of ​​the shaft or other rotating machine element. It is also possible for the temperature measurement in the said surface area to be measured by several pyrometers arranged in a row.

[0013] Furthermore, a thermal imaging camera or an arrangement of several thermal imaging cameras is suitable for the non-contact temperature measurement device. Regarding thermal imaging cameras, reference is made to documents EP 4 157 632 B1 and DE 10 2016 109 628 A1 for background information. In the present case, a combination of at least one thermal imaging camera with a pyrometer is also possible.

[0014] The method for operating a segmented plain bearing according to the application generally provides for non-contact measurement of surface temperatures in surface areas of a mounted machine element located between plain bearing segments. Depending on the result of the non-contact measurements, the operating state of a machine comprising the segmented plain bearing can be changed.

[0015] Temperature measurements recorded with pyrometers and / or at least one thermal imaging camera can be recorded in real time, i.e., without any technically relevant delay, by a data processing system and compared with target temperatures for the current operating condition. If minor deviations between a target and an actual temperature are detected, the data processing system can automatically send corresponding information to a designated location, for example, to the operator, the manufacturer, and / or a company commissioned with maintenance. The recipient of this information then has the option, for example, to dispatch maintenance personnel to the system, in particular the wind turbine, in which the segmented plain bearing is installed.

[0016] However, if significant deviations occur between measured temperatures and target temperatures, the entire system can be automatically shut down as a reaction. As long as this is not necessary, the system can also be automatically transferred to a state favorable for the segmented plain bearing without shutting down. In particular, computer-aided intervention in the bearing's oil balance can be carried out based on the measured shaft temperature. In particular, the amount of lubricating oil supplied to the segmented plain bearing can be regulated as needed. This type of control also contributes to minimizing the power requirements of a lubricating oil pump associated with the bearing.

[0017] The segmented plain bearing can be used, particularly in the form of a large bearing, in stationary systems, such as wind turbines, as part of condition monitoring. The segmented plain bearing can also generally be used in mobile machinery, such as a watercraft. The plain bearing is not necessarily designed as a hydrodynamic bearing. For example, the plain bearing elements can be elements of a hydrostatic bearing.

[0018] Several embodiments of the invention are explained in more detail below with reference to a drawing. These show, partly schematically:

[0019] Fig. 1 shows a first embodiment of a segmented plain bearing with a temperature measuring device,

[0020] Fig. 2 and 3 further embodiments of segmented plain bearings with means for detecting the surface temperature of a mounted shaft.

[0021] Unless otherwise stated, the following explanations apply to all embodiments. Corresponding or essentially equivalent parts are identified by the same reference numerals in all figures.

[0022] A segmented plain bearing, i.e., a bearing assembly, designated overall by reference numeral 1, operates as a hydrodynamic plain bearing and comprises several plain bearing segments 3, four in each of the exemplary embodiments, with which a shaft 2 is mounted. The shaft is generally referred to as a rotatable machine element. In the present cases, the bearing assembly 1, constructed as a segmented bearing, is a radial bearing. Alternatively, the bearing assembly 1 could be designed as an axial bearing or absorb forces in both the axial and radial directions.

[0023] The plain bearing segments 3 present in the embodiments according to Figures 1 to 3 are supported in a housing (likewise not shown) in an at least slightly tiltable manner by axial bearings (not shown). This provides flexible support for each plain bearing segment 3. The bearing assembly 1 is used in a wind turbine as the main rotor bearing. To monitor the temperature of the surface of the shaft 2, a sensor assembly, designated overall by 4, is provided, which in the embodiments according to Figures 1 and 2 comprises a plurality of pyrometers 5 and in the embodiment according to Figure 3 at least one thermal imaging camera 6. The pyrometers 5 and the thermal imaging camera 6 are collectively referred to as temperature measuring devices 5, 6.

[0024] The temperature measuring devices 5, 6 are, as illustrated in Figs. 1 to 3, directed at surface areas of the shaft 2 that are not covered by plain bearing segments 3. In the case of Fig. 1, pyrometers 5 are placed at equal angular intervals of 90° around the center axis of the shaft 2 and thus of the entire bearing arrangement 1. In the embodiment according to Fig. 2, four pyrometers s are arranged one behind the other in the longitudinal direction of the shaft 2, i.e. in the axial direction of the bearing arrangement 1, so that they cover practically the entire axial extent of the plain bearing segments 3. Such detection of a surface area, the extent of which in the longitudinal direction of the shaft 2 is determined by the extension of the plain bearing segments 3 in the axial direction of the bearing arrangement 1, is accomplished in the case of Fig. 3 by a thermal imaging camera 6. In a version not shown in Fig.As can be seen from Fig. 3, several thermal imaging cameras 6, in particular four, can be arranged on the circumference of the bearing assembly 1. Similarly, in the case of Fig. 2, several of the four-unit arrangements of pyrometers 5 illustrated in this figure, in particular four such pyrometer arrangements, can be present.

[0025] As shaft 2 rotates, heat is introduced into shaft 2 due to the friction between the plain bearing segments 3 and shaft 2. During normal operation of bearing assembly 1, this heat input leads at most to a moderate increase in the temperature of shaft 2. However, if undesirable effects occur, such as mixed friction between shaft 2 and the plain bearing segments 3 due to inadequate lubrication, this can result in a rapid temperature increase, which can be quickly detected using sensor assembly 4. A particularly important factor here is that temperature measuring devices 5, 6 are aimed directly at optically detectable, uncovered metallic surface areas of shaft 2. This makes it possible to quickly initiate countermeasures, either automated or through intervention by operating personnel, in the event of an unacceptable temperature increase.Depending on the type of malfunction of the intended operation detected, such countermeasures can range from an increased supply of lubricant to a reduction of the speed of the shaft 2 to the shutdown of the system which includes the bearing arrangement 1.

[0026] List of reference symbols Bearing arrangement, segmented plain bearing Shaft, rotatable machine element Plain bearing segment Sensor arrangement, temperature sensor Pyrometer, temperature measuring device Thermal imaging camera, temperature measuring device

Claims

Patent claims 1. Segmented plain bearing (1) comprising a plurality of plain bearing segments (3), wherein uncovered surface areas of a machine element (2) mounted by means of the plain bearing segments (3) are arranged in circumferential areas between the plain bearing segments (3), and wherein a non-contact temperature measuring device (5, 6) is provided for monitoring the temperature of at least one of these surface areas.

2. Plain bearing (1) according to claim 1, characterized in that the plain bearing segments (3) are designed as axial bearing segments.

3. Plain bearing (1) according to claim 1, characterized in that the plain bearing segments (3) are designed as radial bearing segments.

4. Plain bearing (1) according to claim 3, characterized in that the plain bearing segments (3) provided for radial bearing are in turn each plainly mounted.

5. Plain bearing (1) according to claim 3 or 4, characterized in that at least one pyrometer (5) is provided for measuring the surface temperature of the machine element (2) in a continuous, uncovered surface area.

6. Plain bearing (1) according to claim 5, characterized in that several pyrometers (5) arranged in a row are provided for measuring the temperature in said surface area.

7. Plain bearing (1) according to one of claims 1 to 6, characterized in that the contactless temperature measuring device (5, 6) comprises at least one thermal imaging camera (6).

8. Wind turbine, with a segmented plain bearing (1) designed according to claim 1.

9. Method for operating a segmented plain bearing (1), wherein surface temperatures in surface areas of a mounted machine element (2) which are located between plain bearing segments (3) are measured without contact.

10. Method according to claim 9, characterized in that an operating state of a machine comprising the segmented plain bearing (1) in Depending on the result of the non-contact measurements.

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