WO2025016989A1 - Bearing assembly comprising hydrodynamic plain bearings - Google Patents

Abstract

The invention relates to a bearing assembly comprising at least one first hydrodynamic plain bearing (1) and one second hydrodynamic plain bearing (2), the radial parts of the plain bearings having a different ratio of recess (A) to support surface of the bearing surface (3).

Description

Description

bearing arrangement with hydrodynamic plain bearings

The present invention relates to a bearing arrangement with hydrodynamic plain bearings, as well as a rotor arrangement.

The object of the present invention is in particular to improve the efficiency of a bearing arrangement and, furthermore, to reduce power loss, in particular in an application with hydrodynamic plain bearings.

This object is achieved by a bearing arrangement having the features of claim 1. The subclaims relate to advantageous further developments.

According to one embodiment of the present invention, a bearing arrangement is provided. In one embodiment, the bearing arrangement has at least one first, in particular hydrodynamic, plain bearing. In one embodiment, the bearing arrangement has at least one second, in particular hydrodynamic, plain bearing. In one embodiment, the, in particular radial parts, of the plain bearings have a different ratio of recess to supporting surface of the (inner) bearing surface. In one embodiment, the, in particular radial parts, of the first hydrodynamic plain bearing and the second hydrodynamic plain bearing have a different ratio of recess to supporting surface of the (respective) bearing surface. The term "ratio" or the parts from which the ratio is formed, as used herein, in particular do not refer to a (circumferential) chamfer of the plain bearing or a chamfer that may be present is not included in the, in particular absolute, ratio of recess to supporting surface. In one embodiment, the ratio is an absolute ratio of recess to supporting surface.

Advantageously, in one embodiment, the bearing arrangement can be operated more efficiently, in particular the power loss of the bearing arrangement can be reduced. The term "recess" as used herein is to be understood in particular as a radial and/or axial recess, in particular in sections, of the (sliding) surface of the plain bearing, in particular at least (on) one bearing shell of the plain bearing. In one embodiment, the recess is used to drain lubricant and/or oil, in particular warm lubricant, from the plain bearing. In one embodiment, shear forces in the gap between the plain bearing and the rotor can advantageously be reduced with the aid of the recess(es). In addition, in particular, the recess(es), which in particular also reduce the load-bearing sliding surface, can be used to reduce power losses, in particular in the plain bearing, or to increase the efficiency of the bearing.

The term “plain bearing”, as used herein, is to be understood in particular as the radial part of a plain bearing, further in particular as the radial part of an axial-radial plain bearing, in particular without restriction of generality.

In one embodiment, the first plain bearing has a smaller ratio of recess to supporting surface, in particular compared to the second plain bearing. In one embodiment, the recess in the first plain bearing is smaller (in terms of area) than the recess in the second plain bearing, in particular the supporting surface of the first plain bearing is larger (in terms of area) than in the second plain bearing. In one embodiment, the ratio of the recess to the supporting surface of the (inner) bearing surface of the first plain bearing is smaller than the ratio of the recess to the supporting surface of the second plain bearing.

In one embodiment, this can advantageously reduce power loss in the bearing arrangement.

In one embodiment, the ratio of the recess to the support surface in the first plain bearing is at least 5%P (percentage points), at least 10%P, at least 15%P, at least 20%P, at least 25%P or at least 30%P smaller than the ratio of the recess to the support surface in the second plain bearing and/or at most 40%P, at most 35%P or at most 30%P smaller than the ratio of the recess to the support surface in the second plain bearing. In one embodiment, the ratio of the recess to the support surface in the second plain bearing is at least 10%P, at least 15%P, at least 20%P, at least 25%P or at least 30%P greater than the ratio of the recess to the supporting surface in the first plain bearing and/or at most 40%P, at most 35%P or at most 30%P greater than the ratio of the recess to the supporting surface in the first plain bearing. In one embodiment, the recess on the supporting surface in the first plain bearing is at least 5%P, at least 10%P, at least 15%P, at least 20%P, at least 30%P smaller than in the second plain bearing and/or at most 40%P, at most 30%P smaller than in the second plain bearing.

In one embodiment, this makes it possible to advantageously reduce the power loss, in particular the ratio of recess to supporting surface of the first and second plain bearings can be adjusted to the dynamic forces to be absorbed by the bearing arrangement.

In one embodiment, the first plain bearing is arranged on a side of the bearing arrangement that has a larger static overhang, in particular compared to the other side of the bearing arrangement. In one embodiment, the second plain bearing is arranged on a side of the bearing arrangement that has a smaller static overhang, in particular compared to the other side of the bearing arrangement, further in particular compared to the side of the bearing arrangement on which the first plain bearing is arranged. In one embodiment, the first plain bearing is arranged on a side of the bearing arrangement that has a larger static overhang moment, in particular compared to the other side of the bearing arrangement. In one embodiment, the second plain bearing is arranged on a side of the bearing arrangement that has a smaller static overhang moment, in particular compared to the other side of the bearing arrangement, further in particular compared to the side of the bearing arrangement on which the first plain bearing is arranged. In one embodiment, the first plain bearing is arranged such that it absorbs a larger static overhang moment or is used for this purpose, in particular compared to an arrangement of the second plain bearing that in particular absorbs a smaller static overhang moment or is used for this purpose.

Advantageously, this can reduce power loss, in particular of the bearing arrangement, and in particular the bearing arrangement can be used more efficiently. Advantageously, in one embodiment, In particular, indirectly, a reduction in the amount of oil in the plain bearing or the bearing arrangement can be achieved because the removal of the warm oil or warm lubricant using the recess(es) means that the average temperature in the, in particular the entire, bearing gap is lower and as a result, in particular, an (additional) increase in the oil requirement is not necessary or cannot be necessary in order to reduce the average gap temperature in the bearing.

The term "static overhang" or "static overhang moment", as used herein, should preferably be understood to mean the overhang of a rotor or the like supported by means of the bearing arrangement. In one embodiment, an overhang or overhang moment includes, in particular in addition to the actual rotor overhang, a component or components connected to the rotor, such as in particular hub(s), flange(s), coupling(s) or the like. In particular, in one embodiment, an overhang or overhang moment can increase or is greater if, in particular, two rotors (or the like) are coupled or (actively) connected via a coupling, wherein the mass(es) of the (individual) coupling elements, in particular their effective distances, act on the two coupled or (actively) connected rotors (or the like), so that in particular their static overhang or their static overhang moment is or is increased. In particular, in one embodiment, less damping effect is required by the plain bearing on the side of the smaller static overhang in order to suppress self-excited subsynchronous vibrations. This can be advantageously achieved in one embodiment by at least one recess in the (second) plain bearing - as described herein.

In one embodiment, the second plain bearing is arranged on a side of the bearing arrangement facing away from the clutch. Alternatively or additionally, the second plain bearing is arranged on a non-drive side.

As a result, in one embodiment, the bearing surface or support surface of the second plain bearing can advantageously be reduced, in particular in a targeted manner, so that a power loss of the bearing arrangement can be reduced, in particular compared to a bearing arrangement with identical plain bearings or conditions. In one embodiment, the recess is arranged in sections on a bearing shell that is at least substantially unloaded (during operation). In one embodiment, the recess has several, in particular connected and/or separate, sections, in particular on an (unloaded) bearing shell of the, in particular first and/or second, plain bearing.

In this way, in one embodiment, a (sufficient) damping characteristic, especially when operating with low (radial) loads, can advantageously be achieved with the help of the lubricating film within the wings and power loss can be reduced.

In one embodiment, the recess is formed, in particular in sections, on an unloaded bearing shell and/or at least in sections on a loaded bearing shell, in particular in a second plain bearing, in particular in the first and second plain bearings. In one embodiment, the ratio between recess and supporting surface is smaller in the first plain bearing than in the second plain bearing.

In this way, the power loss can be advantageously reduced in one design, especially when (sufficient) safety is provided for the dynamic loads that arise.

In one embodiment, the recess of a plain bearing is designed such that it occupies at least one axial section of the bearing surface, in particular in sections at most 100% of the bearing surface, at most 75%, at most 50% or at most 30% of the bearing surface and/or in sections at least 1%, at least 2%, at least 3%, at least 5%, at least 10%, at least 20% or at least 25% of the bearing surface, in particular, in one embodiment, in sections 0% of the bearing surface. In one embodiment, a recess boundary and/or recess edge spaced from an axial side surface of the plain bearing runs at least substantially parallel to the axial side surface of the plain bearing or is designed such that, in particular in sections, an axial distance of the recess boundary and/or the recess edge to the axial side surface of the plain bearing changes, in particular continuously or discontinuously. In one In this embodiment, the recess boundary and/or the recess edge is designed as a, in particular continuous, curve in the bearing surface.

In one embodiment, the recess is rectangular, triangular, circular and/or circular segment-like in a plan view of the unrolled bearing surface of the plain bearing; in particular, in one embodiment, the recess is designed as a combination of several geometric figures, such as polygons, circles or the like, in particular as a free form, in a plan view of the unrolled bearing surface of the plain bearing.

In one embodiment, the recess in a rolled bearing surface is cuboid-like, cylinder-(segment-)like, cone-(segment-)like and/or spherical, in particular as a combination of one or more spatial geometric figures.

In this way, in one embodiment, a particularly advantageous oil (discharge) can be achieved, in particular the oil quantity can be guided (more specifically) and/or an average gap temperature and/or (gap) shear forces in the area of the recess(es) can be reduced.

In one design, the transition between the support surface or bearing surface and the recess is sharp-edged. In one design, the transition between the support surface or bearing surface and the recess is continuous and/or rounded.

In one embodiment, the radial depth of the recesses, in particular on both sides, in particular in the edge areas of the bearing surface, is several millimeters, whereby, in one embodiment, a complete radial penetration of the bearing shell can also be formed. In one embodiment, the recess is arranged or provided, in particular for the most part, in the unloaded bearing surface of the plain bearing.

In one embodiment, the first plain bearing and/or the second plain bearing, as described herein, has a fixed-shell plain bearing or is designed as such. In one embodiment, the first plain bearing and/or the second plain bearing does not have a tilting segment plain bearing, in particular with tiltable radial segments, or is not designed as such. In one embodiment, this can advantageously reduce the power loss of the bearing arrangement.

According to one embodiment of the invention, a rotor arrangement is provided. In one embodiment, the rotor arrangement has at least one rotor or at least one shaft or the like. In one embodiment, the rotor arrangement has a bearing arrangement described herein. In one embodiment, the at least one rotor is supported by means of a bearing arrangement described herein.

In rotor dynamics, smaller static rotor overhangs or static overhang moments usually lead to smaller lateral (or radial) deflections or orbits or dynamic forces within the rotor overhang. During operation, the oil film of a plain bearing usually counteracts the dynamic forces due to its stiffness and damping characteristics. The two conical oil film modes that typically occur in conjunction with fixed shell plain bearings during operation with low bearing loads (so-called rigid body modes, in which the rotor, which is stiff relative to the lubricating film, oscillates with a wobbling motion around its axis of rotation within the radial clearances of the at least two plain bearings without bending significantly) can be differentiated by means of their vibration shapes in such a way that the mode that forms its largest orbit along the theoretical rotor axis in the direction of the larger rotor overhang usually has lower damping. In contrast, the mode which forms its largest orbit along the theoretical rotor axis in the direction of the smaller rotor overhang generally has a higher damping. Because the vibration shapes of the two modes differ so much, the damping of a conical mode can (advantageously) be influenced almost independently of the properties of another conical mode, for example by introducing recesses within a single plain bearing, in one design. Since the damping of the rigid body modes can usually be assessed as a measure of safety against the occurrence of oil film instabilities, the power loss can be reduced in particular by specifically reducing the support surface or sliding surface of a, in particular a second, plain bearing (as described herein), and in particular advantageously the rotor application can be made more efficient as a result, furthermore in particular with (design) values that are still sufficient for safety. In particular, the inventor has recognized in measurements that the power loss of the bearing is reduced or, in particular, can be reduced significantly by using a bearing arrangement described herein with, at least substantially, constant operating parameters such as, in particular, rotor speed, power or torque and oil data.

Further advantages and features emerge from the subclaims and the embodiments. This shows, partly schematically:

Fig. 1: a bearing arrangement according to an embodiment of the present invention;

Fig. 2: a rotor arrangement in a perspective and a side view according to an embodiment of the present invention; and

Fig. 3: Recesses according to embodiments of the present invention.

Fig. 1 shows a bearing arrangement, in particular for a rotor. The rotor in Fig. 1 has a smaller overhang on the left side of the schematic representation than on the right side. Accordingly, a plain bearing, described here in particular as a second plain bearing 2, is arranged on the left side, the bearing surface of which has a support surface and lateral recesses A, whereby their ratio to one another (recess A to support surface) is greater in the plain bearing on the left side than in the schematically shown plain bearings 1, T on the right side, which are described in the above description in particular as first plain bearings 1, T. The recesses A shown are each, in particular predominantly, formed in the unloaded bearing shell of the plain bearings, but in one embodiment can also be formed, in particular at least partially, in the loaded bearing shell (in particular during operation), whereby

"loaded" refers in particular to the fact that the (nominal load) vector of the bearing force is located in this bearing shell. A further (first) plain bearing T is shown in dashed lines, which, in a design without recesses, alternatively (to plain bearing 1) supports the right-hand side of the rotor (radially) in the illustration. Fig. 2 shows a further schematic rotor arrangement in a perspective view and a schematic side view, in which the rotors or shafts, in particular gear units (parts), are mounted using bearing arrangements, as described herein. The arrangement shown as an example has a gear unit with bearing arrangement G1, G2, G'1 and G'2. The second plain bearings 2, as described herein, are, particularly advantageously, arranged at G2 and G'2 in the schematic representation of Figure 2, the remaining plain bearings corresponding to first plain bearings 1, as described herein. These bearing arrangement(s) each have second plain bearings 2, as described herein, on the side of the rotors or shafts to be supported radially with the comparatively smaller static overhang or comparatively smaller static overhang moment. It is particularly evident from this that couplings, flanges and/or hubs contribute to the overhang/overhang moment, in particular their masses. From the side view in Fig. 2 it is particularly evident that a recess or recesses are or can be arranged differently in the plain bearing 1, 2 depending on the direction of rotation and/or drive side. In the schematic side view in Fig. 2, the smaller (left) wheel is driven in the direction of the arrow. As a result, the toothing is supported, for example, in such a way that an at least substantially unloaded surface section of the sliding surface of the plain bearing of the small wheel is at least substantially at the bottom (relative to the figure sheet), and for the large (right) wheel, at least substantially at the top. An arrangement of the recess(es) is thus, in one embodiment, dependent on a (nominal) load vector F and the recess(es) is/are, at least substantially, arranged in the surface section of the plain bearing which is, at least substantially, opposite to the (nominal) load vector F, in particular in the, at least substantially, unloaded surface section of the plain bearing 1, 2, further in particular in the sliding surface section of the plain bearing usually referred to as the unloaded segment (“non-load segment”). Accordingly, the (nominal) load vector F changes in the case of an opposite direction of rotation, in particular, in one embodiment, the arrangement or position of the recess(es).

Fig. 3 shows, in the sub-figures A to F, schematically recesses A1 to A6 of the bearing surfaces 3 in different embodiments in a top view. The upper row of exemplary embodiments shows symmetrical recesses in relation to a theoretical center line (theoretical axial bearing center of the radial part) of the plain bearing. Recesses A1-A3. The bottom row shows asymmetrically arranged recesses A1-A6 in relation to the theoretical axial bearing center. The recesses A1-A5 can, in particular in relation to the bearing surface 3, have a rectangular (see A), triangular (see B) or circular (segment)-like (not shown) recess A1-A5 in a rolled-out representation, which is designed symmetrically in particular to the axial bearing center, as shown in particular in sub-figures A, B and C of Figure 3. The recesses A1-A6 can alternatively or additionally be designed asymmetrically in one embodiment, as shown schematically in particular in sub-figures D to F of Figure 3. There, in sub-figure D, two rectangular recesses A1, A2 are combined asymmetrically to the axial bearing center (dotted line) or, as shown in sub-figure E, with a triangular and a circular segment-like recess A3, A4. In part figure F of Fig. 3, a recess A5 with a radius-like edge and a free-form recess A6 are shown. In embodiments, further or other combinations of geometric figures are formed as recesses. The arrows in Fig. 3 indicate a possible direction of rotation 5 of a shaft or a rotor on the bearing surface. Figure 3 does not show a division into loaded and unloaded bearing shells, with the recesses preferably being formed, in embodiments, on the unloaded bearing shell and/or the unloaded segment (“non-load segment”) of the plain bearing 1.

Although exemplary embodiments have been explained in the preceding description, it should be noted that a large number of modifications are possible. It should also be noted that the exemplary embodiments are merely examples that are not intended to limit the scope of protection, applications and structure in any way. Rather, the preceding description provides the person skilled in the art with a guide for implementing at least one exemplary embodiment, whereby various changes, in particular with regard to the function and arrangement of the components described, can be made without departing from the scope of protection as it results from the claims and combinations of features equivalent to these. list of reference symbols

1 , 1' first hydrodynamic plain bearing

2 second hydrodynamic plain bearing 3 bearing surface (inside)

4 rotor

5 Direction of rotation of the rotor

A, A1 ... A6 recess(es)

F Nominal load vector

Claims

patent claims 1. Bearing arrangement comprising: at least a first hydrodynamic plain bearing (1) and a second hydrodynamic plain bearing (2), wherein the radial parts of the plain bearings have a different ratio of recess (A) to supporting surface of the bearing surface (3). 2. Bearing arrangement according to the preceding claim, characterized in that the first plain bearing (1) has a smaller ratio compared to the second plain bearing (2). 3. Bearing arrangement according to one of the preceding claims, characterized in that the ratio in the first plain bearing (1) is at least 5%P smaller than in the second plain bearing (2). 4. Bearing arrangement according to one of the preceding claims, characterized in that the first plain bearing (1) is arranged on a side of the bearing arrangement which has a larger static overhang compared to the other side of the bearing arrangement. 5. Bearing arrangement according to one of the preceding claims, characterized in that the second plain bearing (2) is arranged on a side of the bearing arrangement facing away from the clutch and/or on a non-drive side. 6. Bearing arrangement according to one of the preceding claims, characterized in that the recess (A) is arranged in sections, in particular having several sections, on an unloaded bearing shell of the, in particular second, plain bearing. 7. Bearing arrangement according to one of the preceding claims, characterized in that the recess (A), in particular in sections, is formed in each case on an unloaded bearing shell and/or in each case at least in sections on a loaded bearing shell of the second plain bearing (2), in particular of the first plain bearing (1) and the second plain bearing (2). 8. Rotor arrangement, in particular a gearbox, with at least one bearing arrangement according to one of the preceding claims and a rotor which is mounted in particular with the aid of the bearing arrangement.