WO2011138174A1

WO2011138174A1 - Device for rotatably mounting a shaft, in particular for use in a steam turbine

Info

Publication number: WO2011138174A1
Application number: PCT/EP2011/056379
Authority: WO
Inventors: Maurice Kristen
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-05-04
Filing date: 2011-04-20
Publication date: 2011-11-10
Also published as: DE102010019285A1; EP2531738A1

Abstract

The invention relates to a device (10) for rotatably mounting a shaft (12), in particular of a turbine rotor, comprising a bearing bushing assembly (14) for receiving a section (16) of the shaft (12), wherein, a bearing gap (22) is located between mutually facing bearing surfaces (18, 20) of the bearing bushing assembly (14) on the one side and of the shaft section (16) on the other side, and said bearing gap is filled with a bearing fluid (24). According to the invention, the bearing fluid (24) is an electrorheological fluid, and the device further comprises control means (ST, 14, 16) for generating at least one electrical field in the region of the bearing gap (22). When rotatably mounting, for example, a turbine rotor of a steam turbine, it is thus advantageously possible to influence, during operation, the load-bearing capacity, the required lubricant quantity, and the upper and lower operating limits (for example, maximum and minimum rotational speeds).

Description

description

Device for pivotally mounting a shaft, in particular for use in a steam turbine

The present invention relates to a rotary bearing device according to the preamble of claim 1, in particular for rotation ^¬ storage of the turbine rotor of a steam turbine. Further, the invention makes a ^¬ be equipped with such technical means Drehlagervor- direction (z. B. steam turbine) or the use of the device for a technical device.

Rotary bearing devices according to the preamble of claim 1 are known, for example in the field of computer technology for the rotational mounting of a magnetic storage disk ( "Mem ^¬ cherplattenlaufwerk"), see. z. B. DE 20 2005 000 155 Ul.

In a rotary bearing device of this type, a portion of the shaft to be supported is received in a bearing bushing arrangement. Between bearing surfaces facing one another on the one hand a bearing bush arrangement and on the other hand of Wellenab ^{¬ section} is a bearing gap. The bearing gap Zvi ^¬ rule the mutually facing bearing surfaces is filled with a laser gerfluid (eg., Oil). In rotary bearing devices of this type, which are also referred to as "fluid-dynamic plain bearings", a certain self-centering or self-positioning of the shaft and a smooth and friction-resistant or wear-resistant barrel can advantageously be achieved during relative rotation between shaft and bearing bush arrangement.

It is an object of the present invention to improve a Drehla ^¬ delay of the generic type with regard to their functional properties further, in particular a INTENT in hitherto envisaged applications to enable or special advantages when using the rotary bearing in the respective technical devices to achieve . The rotation-support apparatus according to the invention is characterized in that the bearing fluid is an electrorheological fluid and the apparatus further comprises control means for generating GR nigstens an electric field in the region of Lagerspal ^¬ tes comprises.

An electrorheological fluid has a flow behavior which is variable by an applied electric field. Such fluids, for example based on an oil (eg., Silicone oil or mineral oil) are known and available Kommer ^¬ essential per se. Advantageously, it is therefore possible in the context of the invention to make use of commercially available electrorheological fluids, in particular electrorheological fluids based on an oil.

In the known electrorheological fluids, their viscosity increases with increasing field strength of the electric field. In the case of fluids having polarizable particles dispersed therein, the mechanism of action for this is usually assumed to be a type of chain formation of the particles along the electric field lines.

In the inventive device it is advantageous thus possible to control the viscosity and dynamic viscosity of the existing fluid in the bearing gap bearing means of the Steuermit ^¬ tel for generating an electric field in the bearing gap ge ^¬ aims. The resulting in turn advantages in the operation of the pivot bearing or equipped with such a pivot bearing technical device are diverse and will be explained below.

In one embodiment, it is provided that the control means are adapted to generate the electric field in the radial direction between bearing bushing arrangement and shaft portion extending. This is for many applications a structurally particularly simple implementation in which the already existing bearing bush arrangement (or a part thereof), and the already existing shaft portion (or a portion thereof) can be ge ^¬ uses as a source or sink of electric field. For this purpose, only an electrical control voltage between bearing bush arrangement and shaft section (or relevant parts thereof) to create.

The provided in the generation of a radial electric field extending field sources or sinks can, for. B. surfaces (bearing surfaces) or surface sections of the bearing bush arrangement or the shaft portion may be formed. In particular, the electric field from the bearing surface (or egg ^¬ nem portion thereof) may be provided, running out of the bearing bush arrangement and ends at this point. Alternatively, the electric field may originate from a surface inside the bushing assembly or terminate at this ("buried") surface. With regard to the use of the shaft section as a field source or - valley can z. B. be provided that the electric field from the bearing surface (or a portion thereof) of the shaft portion emanates or ends at this bearing surface. Alter ^¬ natively, the electric field can emanate from a surface in the interior of the shaft portion or end at this inner surface. If the bearing bushing arrangement z. B. from a metallic (or at least electrically conductive) "solid material" be ^¬ , it is for. For example, an integrally connected bearing ring or a bearing ring assembled from several segments, its surface adjacent to the bearing gap (bearing surface) functions as a field source or sink.

In contrast, the realization of a field source or - valley in the interior of a bearing bushing arrangement, for. Example, an integrally connected or composite of several segments ring, realized by the fact that a "composite material" is used, which at least one elekt ^¬ risch conductive material component (as a field source or - valley) in the interior of the bearing bush arrangement and at least a dielectric material component (eg, plastic or ceramic) adjacent thereto and z. B. encompassing reaching to the storage area. According to one embodiment it is provided that the bearing surface (or at least a part thereof) of the Lagerbuchsenanord ^¬ tion and / or the bearing surface (or at least a part thereof) of the shaft portion received therein from a elekt ^¬ risch conductive metal or a metal alloy (z. B.

Steel) is formed.

Alternatively or additionally, each of these bearing surfaces (or at least a part thereof) z. B. plastic (elec ^¬ electrically insulating or electrically conductive) or ceramic be formed det.

The above explanation of various possibilities of arranging field sources or sinks and, in this context, advantageous materials and material combinations applies in particular to rotary bearing devices whose cross-sectional configuration does not change significantly or not significantly over the axial length of the ^device . An example of this is the pivotal mounting of a cylindrical (or conical) shaft section in a hollow cylindrical (or hollow conical), single or multi-segment bearing bush.

In the context of the invention, however, embodiments of the rotary bearing device are particularly interesting, which have two or more distinct "functional areas" viewed in the axial direction.

Thus, according to one embodiment, for example, provided that the bearing bush arrangement comprises a series of axially spaced-apart, electrically iso- Herten and coaxially arranged bearing bush sections. For each bearing bush portion of a sol ^¬ chen axial row each of the embodiments and designs already explained above can be provided again. The electrical insulation between the individual bearing bush sections allows in a simple manner an independent control of the individual bearing bush sections. In turn, resulting benefits will be explained below.

In this case, it can be provided that at least one pair of bearing bush sections which are adjacent to one another in the axial direction are connected to one another via an electrical insulating layer (eg made of plastic, ceramic, etc.). The electrical insulating layer may be used in this connection also advantageous for a ^trailing sealing effect for the bearing fluid in order to reduce a radial exit of the bearing fluid at the point of transition see be- the axially adjacent bearing bush sections.

As an alternative to the electrical insulating layer, the electrical insulation between the axially adjacent bearing bush sections can also be realized by leaving an (axial) gap between the bearing bush sections. Such a gap may then additionally serve as a passage for introducing or discharging bearing fluid into or out of the bearing gap, e.g. B. if the bearing fluid to be circulated in the rotary bearing device.

In this regard, it should be noted that according to a preferred embodiment, in particular for mechanically loaded rotary bearing devices, provision is made in any case for a requirement-based or continuous introduction of bearing fluid into the bearing gap.

For example, in a pivot bearing with a horizontal axis of rotation forcible can (with more or less pressure ER following) introducing bearing fluid in the bearing gap Its purpose ^¬ moderately to before a start of the rotational movement of the above by gravity to the lower apex point of the storage socket-side bearing surface sunken shaft section to raise.

Also, a circulation of the laser, during the rotational movement gerfluides be useful (in a cycle) in which the bearing fluid flows through the bearing gap in a defined manner by ^¬, such as to dissipate generated during operation of the rotary bearing Ver ^¬ loss heat and / or maintain a proper Ensure "lubricating film" in the bearing gap.

Alternatively or in addition to an inlet or outlet passage for the bearing fluid, which is formed by an axial gap between adjacent bearing bush sections, suitable radial bores in a bearing bush or a bearing bush section and / or the shaft section come into consideration, which open into the bearing gap to allow the supply and removal of bearing fluid. In one embodiment of the invention it is provided that the control means for continuous adjustment of the field strength of the electric field ^¬ are formed suitable al ^¬ so z. B. at least one control voltage source with continuously adjustable output voltage (control voltage). One or more control voltages, each of which can easily be switched on and off or steplessly adjusted over a predetermined voltage range, can be applied via a suitable line arrangement to those parts of the rotary bearing device which function as field sources and sinks.

In one embodiment, it is provided that the control means provide in at least one operating mode, the generation of the electric field with varying field strength in the axial direction. To realize this, for example, the structure already explained above with a Rei ^¬ hehe spaced from each other in the axial direction, electrically insulated from each other and arranged coaxially to each other Bearing bush sections may be provided. The thus enabled independent control of several different electric fields (corresponding to the plurality of juxtaposed bearing bush sections) allows such a variation of the field strength over the axial length of the device.

In a preferred embodiment of the invention, a bearing fluid circulation is provided (eg by means of at least one fluid pump), in which the bearing fluid flows in the axial direction in the bearing gap, wherein at the (or at least one) axial end of this flow a Compared to a middle flow section relatively large field strength of the electric field is provided. Due to the thus comparatively large viscosity of the bearing fluid at DIE sem axial end there is provided a "flow barrier", by which is reduced, for example, the requirements for the Leis ^¬ processing ability of fluid handling components, which are used for introducing and / or circulating the bearing fluid.

In a more specific embodiment, the bearing sleeve arrangement comprises at least three comprises axially spaced apart, electrically isolated from each other and coaxially arranged bearing bush sections, the examples of the axially outer bearing bush portions preferably each have a smaller axial length than the intermediate (with ^¬ sized) bearing bushing section exhibit, and wherein the control ^¬ medium in at least one operating mode, the generation of relatively high electric field strengths in the region of the outer sections (compared to the middle section) provide. This results advantageously an axially beideren- ended flow barrier against an axial outlet of the La ^¬ gerfluides. In such a device z. B. one or more inlet passages are arranged in an axially central region of the central bearing bush portion, so that starting from this axial entry point an axial flow of the bearing fluid in entgegenge ^¬ sat directions (to the two fluid barriers out) takes place. In one embodiment, it is provided that the control means provide in at least one operating mode, the generation of the electric field as a function of a measured rotational speed of the shaft and / or other Betriebspara ^¬ meter of the device-containing technical device.

By controlling the electric field generation in dependence on the measured rotational speed (eg. As speed, angular velocity, etc.) an adaptation or optimization of the support function and lubricating function of the bearing fluid over a relatively wide rotation speed range may be done at operably vari ^¬ ierender rotational speed.

For a low wear, it is advantageous if with the bearing fluid located in the bearing gap, a surface-extended lubricant film is provided so that a wear of the bearing surfaces Ver ^¬ avoided by direct solid friction. The lubricating film should not fall below the minimum lubricant film thickness, as can occur with conventional slide bearings with lubricating oils when certain "operating limits" are exceeded (eg in terms of speed, temperature, etc.).

For example: In the case of rotary bearing of a horizontally extending turbine rotor of a steam turbine, apart from the problem of overheating of the lubricant, particularly unacceptable pressure build-up in the lubricant can occur at particularly high rotational speeds, as a result of which the minimum lubricant film thickness can be undershot. On the other hand, an excessively low rotational speed or a start-up of the turbine runner after a standstill may be problema ^¬ table. At low speeds it can happen that in the lower apex area of the pivot bearing not enough

Lubricant pressure is built up to a direct solid contact of the bearing surfaces on the one hand of the turbine rotor and on the other hand reliably avoid the bearing bush arrangement.

In this respect, it is difficult when using conventional bearing fluids, especially in mechanically loaded rotary bearing devices, even at operationally varying rotational speeds always a high load capacity and at the same time to maintain a good lubricating effect. In conventional lubricants, the viscosity is a

Function of the temperature, which in turn can change depending on the speed of rotation. For non-Newtonian fluids comes a time and / or shear rate-dependent Ver ^¬ hold added. As a rule, the latter also applies to common electrorheological storage fluids which can be used within the scope of the invention. Advantageously, however, such can stand by Betriebszu ^¬ (in particular rotational speed and / or temperature) dependent effects are influenced by corresponding active control of the electric field in the desired manner. In particular, an optimization of the mechanical properties of the rotary bearing system (eg damping) can be achieved over a wide range of operating states of the relevant technical device. Another advantage of the inventive design of the pivot bearing device or derer control means, for example, is that the pivot bearing device can also be used for controlled braking of the rotational movement of the shaft by the viscosity of the electrorheological Lagerflu- ides in a controlled manner, in one for the desired braking ^¬ effective extent.

Against this background, in a further aspect, the present invention also relates to a technical device, comprising a pivot bearing device of the type described above, for rotational mounting of a shaft of the technical device. According to a preferred embodiment, it is a technical device in which the axis of rotation of the shaft mounted according to the invention is non-vertical, in particular substantially horizontal.

According to a preferred embodiment, the rotatably mounted shaft portion has a diameter (possibly, with non ^¬ cylindrical shape design, maximum diameter) of more than 50 mm, in particular more than 100 mm.

According to a particularly preferred embodiment, the technical device is a steam turbine, in which the rotary bearing device rotatably supports a turbine rotor or another shaft in the rotary motion path of the steam turbine, for example one directly or indirectly (eg via a gearbox) with the turbine rotor shaft gekop ^¬-coupled shaft.

The steam turbine can z. B. in a power plant or an industrial plant for driving an electric Genera ^¬ sector or a working machine (eg., Compressor) may be provided. In such steam turbines, the thermal energy of supplied steam is converted into mechanical work by means of the turbine rotor rotatably mounted in a steam turbine housing. The least one high-pressure side

Steam inlet into the turbine housing incoming steam drives the turbine rotor usually equipped with a plurality of blades at the axial flow through the turbine housing and exits at least one low-pressure side steam outlet again.

In particular (with a bearing pin diameter of more than 100 mm, in particular more than 200 mm in the region of the male in the bearing bushing assembly shaft portion z. B.), the pivot bearing in such a large-sized shafts high demands on the load-bearing capacity (Dämpfungsei ^¬ properties) as well as at low friction losses so one Rotary bearing device of the type described above is particularly advantageous in such uses.

This is especially true when the control of Drehlagervor- direction by correspondingly controlled generation of Wenig ^¬ least one electrical field in the region of the bearing gap in connection with the control of other equipment components of the technical equipment in question (eg., Steam turbine or steam turbine plant) is carried out.

An example of this is the above-mentioned control of the electric field as a function of a measured rotational speed of the shaft and / or other Betriebspara ^¬ meter of the technical device, eg. B. vibration amplitudes. The inventively provided control means may as ^¬ ago z. B. form part of an already provided for controlling the technical device control device or represent one of several functionalities of such a control device.

Against this background, in a further aspect, the present invention also relates to a method for operating a technical device, which is equipped with (at least) a pivot bearing device of the type described above, wherein the operating method comprises a control of components of the technical device, wherein according to the invention in particular the generation of at least one electrical ^¬ rule field is provided in the region of the bearing gap of the rotary bearing device.

According to a preferred embodiment of the operating method stepless ^¬ A position of the field strength of the electric field takes place in a certain operating mode. According to one embodiment of the operating method, at least one operating mode is provided in which the generation of the electric field is provided with varying field strength viewed in the axial direction. According to an embodiment of the operating method, an operating mode is provided at least, in which takes place the generation of the electric field in dependence on a measured rotational speed of the shaft and / or other operating Para ^¬ meter of the technical device.

According to one embodiment of the operating method, this is used to control the operation of a steam turbine, wherein the rotary bearing device can be provided in particular for the rotary mounting of a turbine rotor of the steam turbine.

The invention will be described below with reference to Ausführungsbei ^¬ games with reference to the accompanying drawings. They each represent schematically:

1 shows a cross section of a rotary bearing for a turbo ^¬ turbine runner in a steam turbine, Fig. 2 shows a longitudinal section in the region of a bearing bushing arrangement of the pivot bearing of Fig. 1,

3 shows a longitudinal section similar to FIG. 2, but for a modified embodiment, in a first operating mode, FIG.

Fig. 4 is a longitudinal section corresponding to Fig. 3, but shown for a second mode of operation, Fig. 5 shows a cross section of a pivot bearing according to another embodiment, and

6 is a block diagram of a steam turbine plant. Fig. 1 illustrates a pivot bearing 10 for pivotally mounting a shaft 12, which in the example shown is the (a horizontal axis of rotation having) turbine rotor of a steam turbine. The rotary bearing 10 arranged in the steam turbine system comprises a bearing bush arrangement 14, which is symbolized in FIG. 1 as composed of four bearing bush segments 14-1 to 14-4. Such in the circumferential direction at one or more locations divided bushings are in particular at pivot bearings for a turbine rotor of a steam engine in use to the turbine rotor z. B. to be able to lift out of its storage in the turbine housing for maintenance after removal of an upper turbine housing part and the or the upper bearing bush segments up.

The gaps shown in FIG. 1 for illustration only between adjacent ones of the bearing bush segments 14-1 to 14-4 are actually not present or sealed.

The bearing bush arrangement 14 serves to receive a section 16 of the shaft 12, wherein bearing bush segments 14-1, 14-2, 14-3 and 14-4 and On the other hand, the shaft portion 16, a bearing gap 22 is present, which with an electrorheological bearing fluid 24 (here:

Electrorheological fluid based on oil) is filled.

The bearing bush segments 14-1 to 14-4 are made of a conductive metallic material elekt ^¬ driven such. B. stainless steel. In the illustrated embodiment, the individual ^¬ nen bearing surface parts 18-1 to 18-4 put together to form a total zy ^¬- cylindrical bearing surface 18 of the bearing bush assembly 14. The bearing surface 20 on the part of the shaft portion 16 is in contrast formed by a cylindrical outer surface of the diameter, for example, about 1.0 to 2.0 parts per thousand smaller shaft portion 16. For the illustrated application of the rotary bearing of a turbine rotor of a steam turbine, the diameter of the shaft portion 16 z. B. some 100 mm, wherein the width of the bearing gap 22 may be on the order of about 0.5 mm or smaller. The upper bearing bush segments 14-1 and 14-4 in FIG. 1 are accommodated in an upper turbine housing part 26. The unte ^¬ ren bushing segments 14-2 and 14-3 are received in a lower turbine housing part 28th The metallic and / or electrically conductive bearing bush segments 14-1 to 14-4 serve in the illustrated embodiment both to provide the bearing surfaces 18-1 to 18-4 (by the inner peripheral surface of the Lagerbuchsenseg ^¬ elements) and as a source of an electric field, which in Area of the bearing gap 22, this enforcing in the radial direction, can be applied to the electrorheological bearing fluid 24.

For this purpose, the bearing bush segments 14-1 to 14-4 are acted upon by suitable line arrangements with a control voltage Us, which is generated or output by a control unit ST as required. The control voltage Us is in this case related to an electrical ground GND which, as in FIG. 1, symbolizes via a suitable line arrangement and z. B. an electrical contact brush 29 is applied to the formed of metallic solid material shaft 12.

Since the turbine housing parts 26, 28 are connected to electrical Mas ^¬ se (ground potential), it is necessary that the bearing bush segments 14-1 to 14-4 to avoid a short circuit to the housing parts 26, 28 are suitably isolated (not shown).

The control unit ST has provided for the operation of the entire system (here: steam turbine) provided functionalities. As Darge ^¬, the control unit ST are supplied to a number of input signals (z. B. operation control signals, sensor signals, etc.) for this purpose, based on which the control unit ST, examples For example, program-controlled, generates a plurality of Ausgangssig ^¬ nals, in particular the mentioned control voltage Us for acting on the pivot bearing 10 with this control voltage Us and thus controlled adjustment of flow behavior, in particular the viscosity of the electrorheological bearing fluid 24. The other, from the control unit ST From ^¬ given signals can z. B. control signals for controlling steam valves and other electrically controllable plant components of the steam turbine.

In the illustrated embodiment results due to the substantially rotationally symmetrical structure of the pivot bearing 10 over the entire circumference of the bearing gap 22 in the radial direction passing through electric field, which is proportional to the applied control voltage Us. The control unit

ST is formed in the illustrated embodiment for outputting a DC voltage which is infinitely adjustable between 0 V and a few 10 ² to about 10 ³ V. Fig. 2 shows the pivot bearing 10 in a longitudinal section. In a viewed in the axial direction middle portion of the bearing bushing assembly 14 inlet openings 30 are arranged, via which, if necessary, bearing fluid into the bearing gap 22 can be ^{¬ introduced} . For example, if the steam turbine to be started up from a standstill, so is particularly recommended a supply of bearing fluid through Eintrittsöff ^¬ voltages 30 in the lower apex region of the bearing gap 22 in order to reliably lenabschnitt a hard ^¬ force-induced direct solid contact between WEL during start-up of the turbine runner 16 of the Turbine rotor and the lower portion of the bearing surface 18 to prevent. Even at this stage, the shaft section 16 is "GETRA ^¬ gen" from the surrounding bearing fluid. After startup, when the turbine runner has reached a certain rotational speed, an active supply of bearing fluid to the hydrostatic lubricant film structure is dispensable. In this phase, due to the Drehbewe ^¬ tion of the shaft 12, a distribution of the bearing fluid in the circumferential direction, which is due to the bearing load and dynamic effects one over the circumference differently strong Lagerfluidschicht sets (lubricating film thickness). In the region of the lower vertex, a pressure of the bearing fluid 24 is established by the rotational movement of the shaft 12.

In order to prevent a loss of bearing fluid during operation or to limit it in a defined manner, suitable seals (eg shaft seals) may be arranged at the two axial ends of the pivot bearing 10. However, this is not the case in the illustrated embodiment. Rather, the bearing fluid in the axial direction occurs after a Druchströmung of Lagerspal ^¬ tes 22 (see FIG. In FIG. 2 drawn arrows) at the axial ends of, is absorbed there or collected and (not shown) in a bearing fluid circuit by means of a pump means via the inlet openings 30 returned back to the bearing gap 22. In addition to the advantage of lower Reibungsverluse (eg., By the shaft sealing rings ^¬) has such a bearing fluid circulation (as required or continuously) the advantage that heat losses from the pivot bearing 10 can be removed.

The properties of the pivot bearing 10 are mainly used by its geometry and the properties of the

Lubricant, here the electrorheological fluid 24 determines. In conventional journal bearings, these properties can not be varied to the temperature dependence of the flow properties ^¬ properties, in particular the viscosity of the lubricant during operation. Due to the inventive use of an electrorheological fluid, however, the dynamic viscosity of the lubricant can be changed in a controlled manner during the Betrie ^¬ esp.

Advantageously, a variable dynamic viscosity of the bearing fluid 20 can be generated by demand-based application of the control voltage Us between the bearing bush arrangement 14 and the shaft 12. With the variable dynamic viscosity of the bearing fluid 20, in particular, the carrying capacity of the sliding bearing 10 in dependence on a rotational speed Speed or speed of the shaft 12 can be adjusted. The tendency of z. Aufzu ^¬ have a lower viscosity as bearing fluids prepared on the basis of an oil with increasing temperature can be accomplished by applying the control voltage Us and ER- heights such control voltage to be counteracted, the

Bearing capacity even at higher temperatures (eg at higher rotational speeds). If at particularly high rotational speeds, due to the concrete design or a specific operating condition, but the problem of a locally too strong increasing ger gerfluiddruckes in the foreground, so at high rotational ^¬ speeds also an active (electrically driven) lowering of the viscosity may be advantageous , Compared to a sliding bearing with conventional lubricant can thus be extended in particular the operating speed range up and down.

A further advantage of the use according to the invention of an electrorheological bearing fluid 24 is the possibility of slowing down the shaft 12 or a system component carried thereby by a specific increase in the viscosity. This can be z. B. at a steam turbine for emergency shutdown z. B. be used in a so-called "quick closure". In the embodiment according to FIGS. 1 and 2, an electric field having viewed in the axial direction gleichmäßi ^¬ ger field strength is generated. The field source and the field sink are ^{¬ formed} by concentric cylindrical surfaces (bearing surfaces 18 and 20).

Hereinafter, a modified embodiment will be explained with reference to FIGS. 3 and 4, in which in particular also in the axial direction in its field strength varying elekt ^¬ rical field can be generated.

In the following description of further embodiments, the same reference numerals are used for equivalent components, each supplemented by a small Letters for distinguishing the embodiment. In this case, essentially only the differences from the exemplary embodiment (s) already described are discussed and, moreover, reference is expressly made to the description of the preceding exemplary embodiments.

As can be seen in FIGS. 3 and 4, a bushing assembly 14a is formed by a series of axially spaced, electrically isolated and coaxially disposed bushing portions 14a-1, 14a-2 and 14a-3. Each of these axial sections can be composed as a one-piece bearing bush ring or, as already explained for the example according to FIGS. 1 and 2, of a plurality of circumferential segments.

Pairwise adjacent bearing bush sections 14a-l to 14a-3 are connected to each other via an electrical insulating ^¬ disc 40a-l or 40a-2 (also je ^¬ Weil composed of several segments). These insulating discs 40a-l and 40a-2 are arranged coaxially to the Lagerbuchsenab ^¬ sections 14a-l to 14a-3, seal these ^{gegenein ¬} other and isolate them electrically from each other.

The illustrated design of the sliding bearing 10a formed in the axial direction from a plurality of "functional areas" opens up the possibility of generating different electric fields at different axial locations.

In one illustrated in Fig. 3 mode of operation of a control unit ST three independently adjustable control voltages Usl, Us2 and Us3 are generated which provided are as ^¬ are applied to the respective axial portions 14a-l, 14a-2 and 14a-3, wherein each of the voltages Usl and Us3 is greater than the voltage Us2. With the illustrated geometry, this results in the viscosity of the electro-rheological bearing fluid 24a being increased in the region of the two axial ends of the sliding bearing 10a in comparison with the viscosity present in the central region. This will sem operating mode advantageously a certain axial barrier ^¬ effect created by the sections 14a-l and 14a-3, wel ^¬ che counteracts an axial outlet of bearing fluid 24a from the bearing ^¬ gap 22a out.

This can z. B. advantageously the need for bearing fluid 24a, which is about the inlet openings 30a in the bearing gap 22a in to introduce or refill, can be reduced. The controlled viscosity increased bearing fluid 24a at the axial ends, as it were, inherently forms its own axial seal. This reduces the power requirements to the means for injecting and / or circulating the bearing fluid 24a. However, in another operating mode, the same sliding bearing 10a can also be controlled so that it corresponds to the plain bearing 10 already described above with reference to FIGS. 1 and 2. This operating mode is shown in FIG. 4 and characterized in that the control unit ST outputs identical control voltages: Usl = Us2 = Us3. This second mode of operation can in particular z. B. are used for braking the shaft 12a.

Fig. 5 illustrates a further modification to the already described above with reference to FIGS. 1 and 2 ^¬ execution form.

In contrast to the example according to Figures 1 and 2, bearing bush segments 14b-1 to 14b-4 are each made of a composite of an electrically insulating material (eg synthetic resin) with field plates 50b-1 to 50b-4 (electrically conductive , made of metal, for example).

Otherwise, the structure of the pivot bearing 10b corresponds to that according to FIGS. 1 and 2. The peculiarities described with reference to FIGS. 3 and 4 could also be used in the pivot bearing 10b. It is essential in the embodiment shown in Fig. 5 that the part of the bearing bush arrangement 14b trained bearing surface 18b is not used simultaneously as a field source or sink and thus z. B. advantageous in terms of their function as a storage area can be optimized. Spatially separated ("buried" in the electrically insulating material), the field plates 50b-1 to 50b-4 act as field source or sink. Thus in turn can be optimized for this function (z. B. in form design) this field ^¬ plates.

Fig. 6 illustrates a steam turbine 60c with a Turbi ^¬ nenläufer 12c (with arranged thereon "blades") arranged in a turbine housing 26c, 28c (arranged with therein "guide vanes") by means of two in each case according to the invention from ^¬ formed pivot bearing 10c-l and 10c -2 is recorded.

The operation of the steam turbine 60c is controlled by an operation ^¬ controller 62c, which for this purpose which therefrom s3 outputs in various per se known type sensor ^¬ signals are input from the steam turbine 60c s2 manipulation control signals sl and, and various control signals for controlling a plurality of system components. This z. B. (not shown) steam valves etc. of the steam turbine 60c driven. The functionalities of the operation control device 62c may in particular also extend to the activation of a transmission 64c and / or an electric generator 66c. Among the output signals s3 are also required for driving the pivot bearing 10c-l and 10c-2 drive voltages (one or more voltages per Drehla ^¬ ger). The operation controller 62c shown thus has functionality as part of the function of the "control unit ST" already described above Ausführungsbei play ^¬. According to an operating mode of the operation controller 62c 10c-l for at least one of the rotary bearings, 10c-2, the He ^¬ generation of the electric field in dependence on a measured rotational speed of the turbine runner 12c and / or other operating parameters (eg. As measured in the region of the pivot bearing Temperature) provided. Corresponding sensor signals (or gebil ^¬ finished based on an evaluation of such sensor signals detection signals) are used as part of the signals S2 to the operation control means 62c supplied.

In summary, it is with the invention, in particular towards ^¬ clearly the pivot bearing a turbine rotor advantageously possible to influence the load-bearing capacity, the amount of lubricant required as well as upper and lower operating limits (z. B. maximum and minimum rotational speed) in operation. Thus, under certain circumstances, an operation can only be made possible, which would be critical using a conventional plain bearing. Especially when used in steam turbines or turbomachines changeable according to the invention dynamic viscosity of the lubricant (bearing fluid) can be used to who ^¬ the, in order to reduce the speed of the turbine rotor faster in a quick closing, so as z. B. to avoid a so-called ventilation (in the final stage of the steam turbine). Also areas to vibrations in critical speed and react to fluctuating loads during loading ^¬ drive (better). In this context, it is important that electrorheological fluids ^generally react extremely rapidly to changes in the electric field.

Claims

claims

1. Device (10) for pivotally mounting a shaft (12), comprising a bearing bush arrangement (14) for receiving a portion (16) of the shaft (12), wherein between a ^¬ other facing bearing surfaces (18, 20) on the one hand, the bearing bush arrangement (14 ) and the other part of the Wellenab ^¬ section (16) is a bearing gap (22) is present, which (with a bearing fluid 24) is filled, characterized in that the La ^¬ gerfluid (24) is an electrorheological fluid and the apparatus further comprises control means (ST, 14, 16) for generating at least one electric field in the region of the La ^¬ gerspaltes (22).

A device (10) according to claim 1, wherein the control means (ST, 14, 16) are adapted to generate the electric field in the radial direction between bearing bushing assembly (14) and shaft portion (16).

3. Device (10) according to one of the preceding claims, wherein the bearing bush arrangement (14) comprises a series of axially spaced-apart, electrically isolated from each other and coaxially arranged bearing bush sections (14-1, 14-2, 14-3).

4. The device (10) according to claim 3, wherein at least one pair of axially adjacent bearing bush sections (14-1, 14-2, 14-3) are connected to each other via an electrical insulating layer (40-1, 40-2).

5. Device (10) according to one of the preceding claims, wherein the control means (ST, 14, 16) are designed to be suitable for continuous adjustment of the field strength of the electric field. Device (10) according to one of the preceding claims, wherein the control means (ST, 14, 16) in at least one operating mode (Figure 3) provide for the generation of the electric field with varying field strength in the axial direction.

Device (10) according to one of the preceding claims, wherein the control means (ST, 14, 16) in at least one operating mode, the generation of the electric field in dependence on a measured rotational speed of the shaft (12) and / or other operating parameters (s2) one of Provide device containing technical device (60).

Technical device (60), in particular steam turbine, comprising a device (10) according to one of claims 1 to 7 for the rotary mounting of a shaft (12) of the technical device.