Axial fault compensation using compensating mass

Abstract

Method for assembling an axial sliding bearing (4, 5) in the manufacture of a turbomachine, comprising a stationary bearing part (4) and a rotatable bearing part (5), the latter having a sliding disk (6) supported on an end face of the stationary bearing part (4) and at least one bearing component (7, 9) provided for rotationally fixed engagement on a shaft (2), wherein the sliding disk (6) and the bearing component (7, 9) are pushed onto the shaft (2) so that the bearing component (7, 9) is rotatably engaged with the shaft (2) and the assembly thus formed is subsequently axially joined with the stationary bearing part (4), characterized in that a plastically deformable,a hardening compensating compound is applied and the sliding disc (6) is pressed against the bearing component (7, 9) by the stationary bearing part (4) during axial assembly under the application of an assembly force, whereby a shape is imprinted on the compensating compound due to the assembly force and the shape of the space area (8, 15, 16) and the compensating compound subsequently hardens, so that this imprinted shape is permanent.

Description

[0001] The invention relates to an axial plain bearing for the shaft of a turbomachine, in particular a centrifugal pump, comprising a stationary bearing part and a rotatable bearing part, wherein the rotatable bearing part has a sliding disk supported against an end face of the stationary bearing part and at least one bearing component provided for rotationally fixed engagement on a shaft. Furthermore, the invention relates to a method for assembling such an axial plain bearing during the manufacture of the turbomachine, in which the sliding disk and the bearing component are pushed onto the shaft so that the bearing component is rotatably engaged with the shaft, and the assembly thus formed is then axially joined with the stationary bearing part.

[0002] During operation, the inertia of the pumped fluid exerts an axial force on the shaft of a turbomachine. This force must be absorbed by an axial bearing to limit axial displacement or movement of the shaft. This prevents rotating components, such as the impeller mounted on the shaft, from contacting the pump housing. In wet-rotor centrifugal pumps, axial support is typically achieved by having a sliding disk of a bearing element rotating with the shaft bearing against the end face of a stationary bearing element. This stationary bearing element usually also serves as a radial bearing. Another radial bearing supports the shaft at a different point.

[0003] Several factors cause the sliding surfaces of an axial bearing to be non-parallel. These factors include component tolerances and manufacturing tolerances / assembly inaccuracies, resulting in either the sliding surface of the stationary bearing part not being perpendicular to the shaft axis, the sliding surface of the sliding disc not being perpendicular to the shaft axis, or the two radial bearings not being exactly coaxial. It is important to note that component tolerances are cumulative. This leads to static and dynamic angular errors in the axial sliding bearing, so that the sliding partners are not perfectly parallel. Static angular errors arise, for example, from the tolerances of the components on the shaft. These require a one-time adjustment.Dynamic angular misalignments occur in radial bearings that are not coaxially mounted and in the case of a sliding surface of the stationary bearing part that is not perpendicular to the shaft axis. These misalignments necessitate compensation for each revolution. In any case, angular misalignments lead to friction losses and increased wear of the bearing components, thus reducing efficiency.

[0004] A plain bearing of the type mentioned in the introduction is known from WO 2016 / 089 680 A1. It discloses that a superhard bearing element is bonded at its underside to a substrate consisting of a cement material (cobalt-cemented tungsten carbide substrate). The bonding process serves solely to provide a secure, adhesive bond to the bearing element on a support ring. This bearing assembly is manufactured separately from other bearing components, with which it forms the axial plain bearing. After the cement mixture has hardened, the bearing assembly is mounted. The plain bearing cannot compensate for any axial misalignment.

[0005] Another plain bearing of the type mentioned in the introduction is disclosed in DE 10 2004 051 400 A1. It describes a damping element in the form of a rubber O-ring between a bearing seat and a bearing disc. This damping element is also unable to compensate for any angular errors caused by assembly.

[0006] Document US 2015 / 0159693A1 describes a bearing assembly for a wind turbine. The bearing assembly comprises several bearing segments that define a sliding element and a bearing body, wherein the sliding element and the bearing body are connected to each other, and the several bearing segments are coupled together to define an annular bearing structure.

[0007] Further details regarding plain bearings are revealed in US 6 024 494 A and US 4 927 275 A.

[0008] To avoid alignment inaccuracies, German patent application DE 196 18 767 A1 proposes a self-aligning axial bearing for high-pressure centrifugal pumps. The rotating counter-bearing is characterized by the fact that the annular surface of the sliding disc, against which the end face of the stationary bearing part rests, is convex, in particular spherical. The spherical design of the sliding bearing reduces the contact area of ​​the bearing surfaces, thereby reducing the tendency to seize. Furthermore, self-alignment of the bearing surface is achieved under high axial forces because the spherical sliding disc rolls on the end face of the stationary bearing part, thus ensuring uniform contact of the sliding surfaces despite the shaft being inclined.However, the smaller contact area between the sliding disc and the end face of the stationary bearing component leads to higher friction and thus to faster wear, at least of the softer sliding partner. Furthermore, manufacturing convex sliding discs with tight tolerances is more complex than manufacturing flat sliding discs.

[0009] In the manufacture of turbomachinery, the axial positioning of the stationary bearing component relative to other components, such as the pump housing, is often of great importance. For example, centrifugal pumps with enclosed radial impellers have seals between the impeller's suction inlet and the inside of the suction channel leading into the pump chamber. The sealing effect of these seals depends crucially on the position of the impeller and the associated shaft and rotor assembly. Furthermore, the impeller can rub against the pump housing if excessive axial play in the shaft causes this assembly to be drawn too far forward. The axial bearing must prevent this, which requires high precision in the components and tight assembly, meaning only minimal tolerances are permitted. This makes the manufacture of the turbomachine complex and expensive.

[0010] The object of the invention is to provide an axial sliding bearing and a method for its assembly in which angular errors between the sliding disk of the rotatable bearing part and the end face of the stationary bearing part and / or axial positioning errors of the rotating to the static components are eliminated during manufacturing.

[0011] This problem is solved by a method with the features specified in claim 1 and an axial sliding bearing with the features specified in claim 4. Preferred embodiments are described in the respective dependent claims and the following description, for which the figures must also be taken into account.

[0012] The axial sliding bearing according to the invention is characterized in that a substantially annular space is located between the sliding disc and the bearing component, which is filled with a compensating compound that is plastically deformable in the processing state and hardens there. This compensating compound between the sliding disc and the bearing component allows manufacturing and tolerance-related errors, both angular errors between the sliding partners and axial errors, to be compensated for, or these errors are already compensated for during the manufacturing of the axial bearing.

[0013] During the manufacturing of the turbomachine, the compensating mass is placed between the sliding disc and the bearing component. The sliding disc is then pressed against the bearing component by the stationary bearing part during axial assembly, applying an assembly force. This automatically results in the sliding surface of the disc being aligned parallel to the face of the stationary bearing part. Furthermore, the sliding disc is pressed into the compensating mass only to the extent necessary for precise axial positioning of the thrust bearing.

[0014] The hardening compensating mass therefore compensates for manufacturing inaccuracies in the components of the turbomachine, in particular the shaft, the impeller, the mounting element, the stationary bearing part, as well as manufacturing inaccuracies in the assembly of the components, in particular in the axial positioning of the sliding disc, the bearing component and the impeller on the shaft and the stationary bearing part relative to the pump housing, for example on a bearing shield that may be attached to the stator housing or a canned tube.

[0015] The use of a self-hardening compensating compound offers the advantage that, despite manufacturing tolerances of the components, the sliding disc is aligned so that it rests flat on the face of the stationary bearing element and is axially correctly positioned. This reduces friction losses and wear, thus increasing the service life and efficiency of the turbomachine. Maintenance requirements are thereby reduced, and the turbomachine's downtime is minimized.

[0016] The compensating compound is plastically deformable in its processing state, i.e., at the time of manufacturing the axial bearing, for example, in the form of a flowable or spreadable paste or gel. It therefore retains the shape imposed upon it by the assembly force and the shape of the mounting area and then subsequently hardens, so that this shape is permanent. The sliding disc is thus held in an optimal position. In this context, "hardening" refers to the transition from an initial chemical-physical state of the compensating compound, in which it is permanently plastically deformable, to a final state in which it is no longer deformable or only elastically deformable.

[0017] Preferably, the sliding disc can be bonded to the bearing component by means of the compensating compound. The sliding disc is thus held to the bearing component by an adhesive bond, allowing torque to be transmitted via this connection.

[0018] To compensate for errors, a space exists between the sliding disc and the bearing component, which is filled by the compensating compound. This space is bounded in one axial direction by the end face of the sliding disc facing away from the stationary bearing part and in the other axial direction by the bearing component. After the sliding bearing is installed, this space essentially has the shape of an annular disk. Depending on the compensating effect, the space can consist of one or two sub-areas. Two sub-areas exist when both angular and axial error compensation is performed. Conversely, only one sub-area exists when only angular or only axial error compensation is performed.

[0019] In the case of angular error compensation, the spatial region has the form of an annular disk with diverging axial surfaces. The axial surfaces are therefore at an angle to each other. In the case of axial error compensation, the spatial region has the form of an annular disk with plane-parallel axial surfaces. The axial surfaces are therefore parallel to each other. If both angular error compensation and axial error compensation occur, each of these compensation effects leads to a corresponding subregion of the spatial region: axial error compensation to a first subregion in the form of an annular disk with plane-parallel axial surfaces, and angular error compensation to a second subregion in the form of an annular disk with diverging axial surfaces.

[0020] In a first embodiment, the bearing component can be a hat-shaped receiving element for the sliding disc. In this embodiment, the rotating bearing part is preferably two-part, i.e., consisting only of the sliding disc and the receiving element. The hat-shaped receiving element helps to achieve coaxial alignment of the sliding disc on the shaft. Furthermore, it protects the sliding disc. In addition, if made of an elastic material, it can dampen vibrations. It can also transmit torque to the sliding disc through frictional or positive engagement. As will be explained below, it can also serve to create a space for excess balancing mass. Advantageously, the hat shape also increases the contact area between the sliding disc and the bearing element, including the balancing mass.

[0021] A preferred embodiment of the invention provides that the rotating bearing part is constructed in at least three parts. The bearing component can be a support ring arranged between the sliding disc and a second bearing component of the rotatable bearing part. This second bearing component can then correspond to the hat-shaped receiving element and preferably accommodate the support ring and the sliding disc. In this embodiment, the support ring is arranged between the sliding disc and the receiving element.

[0022] According to a further development of this variant, a first space can be located between the sliding disc and the support ring, and a second space, which is also filled with a compensating compound that is plastically deformable in its processed state and hardens there, can be located between the support ring and the second bearing component or the receiving element. Thus, for example, the compensating compound present in the first space can compensate for angular misalignment, and the compensating compound present in the second space can compensate for axial misalignment.

[0023] In the version of the plain bearing with a support ring, the compensating compound can be located either between the sliding disc and the support ring, or both between the sliding disc and the support ring on the one hand, and between the support ring and the mounting element on the other. In the first variant, the sliding disc can be bonded to the support ring by means of the compensating compound, which in turn can be firmly connected to the mounting element. The latter can be achieved in various ways, for example by injection molding, bonding, or welding, depending on the material from which the support ring and the mounting element are made.

[0024] Preferably, the bearing component, in particular the support ring, can have a conical or spherical projection on its inner circumference, directed towards the sliding disc, wherein the sliding disc itself has a corresponding chamfer on the inner circumference of its end face facing the bearing component, into which the projection extends at least partially. This ensures that the sliding disc is centered with respect to the shaft axis and, in particular, remains centered even during angular misalignment compensation, which is achieved by the sliding disc rolling on the projection. The projection facilitates or supports angular misalignment compensation and results in a more robust and mechanically resilient mounting of the sliding disc on the bearing component, thus increasing the service life of the axial sliding bearing.

[0025] In this context, a conical or spherical projection is understood to be a projection which, viewed in an axial cross-section through the shaft axis, exhibits a conical or spherical outer contour. Thus, the projection may run parallel to the shaft on its inner circumference, but its radially outer surface corresponds to the surface of a conical disk, a spherical disk, or a torus disk. The outer contour of the projection, viewed in cross-section, is therefore either a chamfer or a radius, allowing the support ring to roll on a corresponding chamfer on the opposite sliding disk.

[0026] In one embodiment, the projection can be ring-shaped, i.e., forming a continuous ring. However, it can also be formed by a number of at least three individual projections, each with an outer contour that is beveled or rounded.

[0027] According to one design variant, the support ring can form part of the receiving element, i.e., be integrally formed with it. This has the advantage that it does not need to be attached separately to or within the receiving element, thus reducing the number of components for the sliding bearing.

[0028] One embodiment of the invention provides that the compensating compound is inelastic in its hardened state. This creates a rigid connection between the sliding disc and the receiving element, permanently fixing the position of the sliding disc. Mechanical forces can also be transmitted via this connection. Advantageously, this leads to optimal alignment of the sliding disc even during prolonged use, thus reducing wear. An inelastic compensating compound is particularly suitable when only static angular errors and / or axial positioning errors need to be compensated, as only a single adjustment is required in these cases.

[0029] An epoxy resin or another hardening adhesive, such as a cement-like substance, can be used as a leveling compound that is inelastic when hardened. Such a compound can consist of a binder and a powdered solid, suitablely quartz powder or ceramic powder.

[0030] According to an alternative embodiment, the leveling compound can be elastic in its hardened state. In this context, it should be noted again that whenever the invention refers to a "hardened state," "hardening," or "curing," it only means the transition from the plastically formable, pasty, or gel-like initial state of the leveling compound to the final state, which is no longer permanently deformable. Thus, the final state of the leveling compound can result in either an inelastic, force-transmitting connection or an elastic, force-absorbing connection.

[0031] Dynamic angular misalignments, i.e., misalignments requiring adjustment per revolution, can be compensated for by a compensating compound that is elastic in its hardened state. Furthermore, a damping effect is achieved. Pressure surges acting on the shaft are thereby mitigated, increasing the service life of the axial bearing. Vibrations that can arise from unevenness in the axial bearing's sliding surfaces are also absorbed by the compensating compound. Due to its damping effect, an elastic compensating compound offers the overall advantage of smoother operation of the axial sliding bearing and extends its service life. Examples of suitable compensating compounds include elastomers, silicones, natural rubbers, and synthetic rubbers.

[0032] Preferably, a compensating compound can be used that hardens within a period sufficient to allow for the assembly of the individual components of the turbomachine, for example, 12 to 24 hours. Preferably, the hardening process can be activated or accelerated after the axial assembly of the thrust bearing components, for example, by exposing the thrust bearing to a specific high temperature or UV light. The UV light can, for example, be applied radially into the bearing from the side. This can reduce manufacturing times.

[0033] According to one embodiment of the invention, the sliding disc, the support ring, and / or the receiving element can have at least one clearance space for receiving excess balancing mass. Alternatively or cumulatively, a clearance space for receiving excess balancing mass can be formed between the sliding disc and the bearing component, as will be further clarified below.

[0034] The clearance space can be formed, for example, by a recess, ideally in the form of a depression in the sliding disc, the support disc, or the receiving element. This prevents the compensating compound displaced from the space between the sliding disc and the receiving element from oozing radially outwards, or only to a minimal extent, and then protruding radially beyond the edge of the sliding bearing disc. Advantageously, this also prevents unwanted contamination of other components by the compensating compound during manufacturing.

[0035] To avoid imbalance due to asymmetrical distribution of the balancing mass when applying the assembly force, it is advantageous to rotate the shaft during the assembly of the axial bearing so that the balancing mass can distribute itself evenly in the radial direction due to the centrifugal force.

[0036] One embodiment of the invention provides that the support ring is made of an elastomer, i.e., an elastomeric plastic. This has the advantage that the support ring can be manufactured easily, particularly by injection molding. Ideally, it can also be directly injection-molded onto the receiving element. Furthermore, like an elastic compensating mass, an elastomeric support ring dampens vibrations and pressure surges at the axial sliding bearing, thereby reducing the force exerted on the other components of the sliding bearing. This increases the service life of the axial bearing. In combination with an elastic compensating mass, this damping effect is enhanced.

[0037] The sliding disc can be made of graphite, metal, ceramic, plastic, or a combination of these materials, as is conventional practice. Furthermore, the mounting element can preferably be made of metal, for example, a deep-drawn part. This ensures maximum dimensional stability and torsional rigidity. The mounting element can also be press-fitted onto the shaft. A metallic mounting element exhibits minimal deformation and is robust against external forces. This advantageously results in a long service life and high load-bearing capacity for a metal mounting element.

[0038] According to one embodiment, the receiving element is designed only as an annular disk that limits the space in an axial direction. Alternatively, the support ring can be attached to the receiving element or formed integrally with it, so that the support ring limits the space in an axial direction. In both cases, the space to be filled or already filled with compensating compound is open to the outside in a radial direction.

[0039] According to another embodiment of the invention, the hat-shaped receiving element can be designed to circumferentially encompass the sliding disc at least partially, and in particular section by section, its outer circumference, wherein the outer diameter of the sliding disc is smaller than the inner diameter of the encompassing part of the receiving element. This limits the axial space between the sliding disc and the receiving element in the radial direction. It is then no longer open to the outside in the radial direction. This creates a radial annular space between the sliding disc and the receiving element, into which the axial space transitions.

[0040] In an advantageous further development of the axial bearing, the receiving element can be designed so that it not only partially but completely surrounds the sliding disc in the circumferential direction, thus completely closing the radial annular space to the outside. This annular space can then act as a space between the sliding disc and the receiving element for excess balancing mass, preventing it from oozing radially out of the sliding bearing.

[0041] Furthermore, the complete encirclement of the sliding disc allows for an adhesive bond between the sliding disc and the receiving element in the radial direction, meaning the sliding disc can be completely surrounded by compensating compound, thus increasing the area of ​​the bonded connection. This has the advantage of increasing the service life of the axial sliding bearing and achieving a higher load-bearing capacity.

[0042] In the inventive method, during axial assembly, the sliding disc is pressed by the stationary bearing part against the bearing component, in particular the receiving element or the support ring, by applying an assembly force. Angular and axial errors are compensated for by the compensating mass between the sliding disc and the bearing component even during assembly. A plane-parallel contact between the end face of the stationary bearing part and the sliding disc is achieved.

[0043] The axial assembly force can be generated by pressing the bearing component, or the shaft rigidly connected to it, along with the sliding disc still floating on the shaft, against the stationary bearing part, thereby pressing the sliding disc against the bearing component. Alternatively, the axial assembly force can be generated by pressing the stationary bearing part, or a component rigidly connected to it such as a bearing shield, the motor housing, or a split tube, towards the bearing component, thereby pressing the sliding disc, still floating on the shaft, against the bearing component from the end face of the stationary bearing part. The invention is therefore not limited to a specific direction of action of the assembly force.

[0044] To achieve rotationally fixed mounting of the bearing component on the shaft, a positive fit can be used, for example, by means of a tongue-and-groove connection or an interference fit. An interference fit has the advantage over a positive fit that no machining of the shaft is required. In contrast, a positive fit is capable of transmitting a higher torque.

[0045] Advantageously, the assembly force can be applied until the compensating compound has hardened. This ensures that the position and orientation of the axial bearing components do not change after the rotating and shaft-supporting components of the turbomachine are assembled, i.e., the sliding disc remains in the compensating position after hardening.

[0046] Further features and advantages of the invention are described below with reference to embodiments and the accompanying figures. These show: Fig. 1 the longitudinal section through an axial sliding bearing according to the invention, which is arranged on the shaft of a turbomachine; Fig. 2a a schematic representation of an axial sliding bearing that compensates for an angular misalignment, Fig. 2b a schematic representation of an axial sliding bearing that compensates for an angular misalignment and an axial error Fig. 2c a schematic representation of an axial sliding bearing as in Fig. 2a, however, with a support ring, Fig. 2d a schematic representation of an axial sliding bearing as in Fig. 2b, however, a radial section through a rotatable bearing part with a support ring and two compensating spaces.

[0047] In Fig. Figure 1 shows an axial plain bearing 4, 5 for the shaft 2 of a turbomachine 1, wherein the axial plain bearing 4, 5 has a stationary bearing part 4 and a rotatable bearing part 5, which is mounted on the shaft in a rotationally fixed manner. The stationary bearing part 4 is held on a bearing shield 12, which is only partially shown. The turbomachine is, by way of example, a centrifugal pump, in particular of wet rotor design, so that the plain bearing 4, 5 is lubricated by the pumped medium. In addition to the rotatable bearing part 5, a rotor 10 and an impeller 11 are arranged on the shaft 2 and rotatably mounted by the stationary bearing part 4, which simultaneously forms a radial bearing.

[0048] The rotatable bearing part 5 consists of a sliding disc 6, a receiving element 7, and a support ring 9 located between them. The sliding disc 6 bears against an end face of the stationary bearing part 4, transmitting force. Its opposite end face rests against a support ring 9, which is press-fitted to the shaft 2 to prevent rotation. The rear side of the support ring 9, facing away from the sliding disc 6, also rests against the inside of a hat-shaped receiving element 7, which is likewise press-fitted to the shaft 2.The receiving element 7 consists of a disc-shaped central part 7a, from the outer circumference of which a first annular part 7b extends axially parallel to the shaft 2 and thereby encompasses the support ring 9 and the sliding disc 6 on the outside, and from the inner circumference of which a second annular part 7c extends axially parallel to the shaft 2 and thereby rests forcefully against the shaft 2.

[0049] The end face of the stationary bearing part 4, facing the rotatable bearing part 5, is not perpendicular to the shaft axis 18, resulting in an angular error α. Nevertheless, the sliding disc 6 rests flat against this end face, so that the angular error α becomes noticeable within the rotating bearing part 5, namely between the sliding disc 6 and the support ring 9. Here, a space 8 exists which, according to the invention, is filled with a compensating compound that ensures the plane-parallel alignment of the running surface of the sliding disc 6 with the stationary bearing part 4 during assembly of the components. This space 8 is hereinafter also referred to as the compensating space 8.

[0050] During the assembly of the axial bearing 4, 5, this compensating compound is malleable, in particular a pasty or gel-like mass. It is applied to the sliding disc, the support ring 9, and / or the mounting element 7 before or after the mounting of the shaft, so that these components are joined to the shaft 2 together with the compensating compound. Alternatively, the compensating compound can be introduced into the space or spaces formed between these components after they have been joined to the shaft 2.

[0051] For example, the compensating compound can be applied to the sliding disc 6, which is then axially slid onto the shaft 2 so that the sliding disc 6 adheres slightly to the support ring 9. Subsequently, the other components of the turbomachine are axially assembled. As a result of an assembly force, for example exerted on the shaft 2, the stationary bearing part 4 and the support ring 9 are pressed against each other, which in turn presses the sliding disc 6 against the support ring 9. The sliding disc 6, which was previously perpendicular to the shaft 2, is thereby aligned parallel to the end face of the stationary bearing part 4, which is not perpendicular to the shaft axis, thus eliminating the angular error α. The compensating compound then hardens and permanently holds the sliding disc 6 in this aligned position.

[0052] The compensating mass in the space area 8 / compensating space 8 is therefore intended to compensate for tolerances and inaccuracies in the components and the manufacturing process and to ensure a plane-parallel alignment of the running surface of the sliding disc 6 to the end face of the stationary bearing part 4.

[0053] The support ring 9 has an annular projection 13 on its inner circumference, directed towards the sliding disk 6. The outer contour of this projection is inclined to the shaft axis 18 and is defined, in particular, by the outer surface of a conical disk whose axis lies on the shaft axis 18. The projection 13 can therefore be considered conical in its overall cross-section. Alternatively, the outer contour can also be arcuate, defined, in particular, by the outer contour of a spherical disk or torus disk. In this case, the projection 13 can be considered spherical in its overall cross-section.

[0054] The sliding disc 6 has a chamfer 17 on its inner circumference, on the end face facing the receiving element 7. This chamfer is designed to at least partially receive the projection 13, i.e., it corresponds to the projection in shape and size. Through the interaction of the projection and the chamfer, the sliding disc 6 is movably mounted on the support ring 9 within certain limits. This allows the axis of the sliding disc 9 to be aligned relative to the shaft axis 18 so that it lies perpendicular to the end face of the stationary bearing part. The sliding disc 6 aligns itself on the projection and essentially rolls on it when the sliding bearing 4, 5 is assembled. Thus, the projection 13 and the chamfer 17 support the plane-parallel alignment of the sliding disc 6 with the stationary bearing part 4. A similar embodiment is also described in Fig. 2c is shown schematically, which represents an axial longitudinal section through the rotatable bearing part 5.

[0055] The leveling compound is in the example in Fig. 1 is chosen such that it is elastic in the hardened state. It is, for example, an elastomer, a silicone, a natural rubber, or a synthetic rubber. This is essential for compensating for dynamic angular errors α unless the support ring 9 is elastic, since the sliding disc 6 must remain permanently in the aligned position to ensure a flat contact with the bearing partner. This means that, with reference to the illustration in Fig. 1. The part of the rotating bearing element 5 located above the shaft axis 18 must always have a larger space 8 in the axial direction, or a larger gap between the sliding disc 6 and the support ring 9, than the part located below the shaft axis 18. Nevertheless, the sliding disc 6 rotates along with the support ring 9 and the receiving element 7. This means that if the shaft were to rotate 180°, the larger space 8, i.e., the larger gap width, would be at the bottom. However, the sliding disc 6 would then no longer be in full contact with the stationary bearing element 4, and the angular error would have doubled. Therefore, it must be ensured that the axial width of the space 8 remains constant at every circumferential point during operation, even though the solidified compensating mass rotates with the shaft. To guarantee this, the compensating mass is elastic.During operation of the turbomachine, it is compressed in the area below the shaft axis and stretched in the area above the shaft axis. Alternatively, the support ring 9 can be elastic and thus effect the necessary compensating movement.

[0056] Furthermore, the use of a compensating compound that is elastic in its hardened state after curing makes it possible to reduce the forces acting on the sliding disc 6 and thus the load on the axial sliding bearing 4, 5 during pressure surges. This increases the service life of the axial sliding bearing.

[0057] In Fig. Figure 2a shows a radial longitudinal section through the rotatable bearing part 5, with the dashed line indicating the axis 18 of the shaft 2. In this schematic representation of the rotatable bearing part 5, the compensating gap 8 is formed directly between the sliding disk 6 and the receiving element 7. The embodiment variant in [Figure 2a] is missing. Fig. 2a consequently compared to the variant in Fig. 1 on a support ring 9. The compensating gap 8 is also filled with a compensating compound. This compensating compound can be inelastic or elastic depending on the application.

[0058] As in Fig. As shown in Figure 2b, the space 8 between the sliding disk 6 and the receiving element 7 is divided into a first and a second sub-space 15, 16, corresponding to the compensating effect of the compensating mass. Here too, the support ring is absent, so that the two sub-spaces are adjacent to each other. The first sub-space forms an axial compensation space 15, and the second sub-space an angular compensation space 16. Axial errors are compensated by the axial compensation space 15. It corresponds to the shape of a circular disk with plane-parallel end faces. The angular compensation space 16 is designed to compensate for angular errors. It corresponds to the shape of a circular disk with diverging end faces.

[0059] Typically, the angular compensation chamber is designed to compensate for angular errors of up to 5° with respect to a radial plane relative to the shaft axis. The axial compensation chamber 15 has a width of 0.2 mm to 1.5 mm in the direction of the longitudinal axis of the shaft 2 and can thus compensate for typical manufacturing deviations in the production of turbomachinery.

[0060] The schematic representation of the rotatable bearing part 5 in Fig. 2c shows an embodiment of the invention accordingly Fig. 1, in which a support ring 9 is arranged between the sliding disc 6 and the receiving element 7, the support ring having a conical projection 13 on its inner circumference that points towards the sliding disc 6. This conical projection 13 is received by a chamfer 17 on the inner circumference of the sliding disc 6. The back of the support ring 9 rests directly against the inside of the receiving element 7, so that the space 8 filled with compensating compound is located between the sliding disc 6 and the support ring 9.

[0061] In this case, the support ring 9 consists of an elastomer and thus enables the damping of pressure surges on the sliding disc 6 as well as the local maintenance of a constant axial width of the space area 8 during operation of the turbomachine. EPDM, for example, is a suitable material. An elastomeric support ring 9 can be used in combination with or as an alternative to an elastic leveling compound.

[0062] In Fig. Figure 2d shows an embodiment of the invention in which the axial compensation chamber 15 is located between the support ring 9 and the receiving element 7, and the angular compensation chamber 16 is located between the sliding disc 6 and the support ring 9. In this embodiment of the invention, two different compensating materials can be used for the two sub-areas 15 and 16, since they are separated from each other by the support ring 9. For example, the axial compensation chamber 15 could be filled with a first compensating material that is elastic in its hardened state in order to dampen forces acting in the axial direction. The angular compensation chamber 16 can be filled with a second compensating material that is inelastic in its hardened state in order to prevent the sliding disc 6 from tilting relative to the longitudinal axis of the shaft 2 and to ensure that the sliding disc 6 rests in a plane-parallel bearing position on an end face of the stationary bearing part 4.

[0063] The sliding disc 6 can be made of graphite, metal, ceramic, or plastic in all the aforementioned embodiments, in order to achieve good sliding properties. The receiving element 7 is preferably made of metal, as this ensures a high load-bearing capacity of the axial sliding bearing.

[0064] As shown in the figures, the receiving element 7 surrounds the sliding disc 6 in the circumferential direction, the outer diameter of the sliding disc 6 being smaller than the inner diameter of the encompassing part 7b of the receiving element 7. In this way, a clearance space 14 is created in the radial direction between the sliding disc 6 and the receiving element 7, into which excess compensating material from the space 8 can flow. This prevents compensating material from protruding radially during the assembly of the axial sliding bearing and potentially contaminating other components. Preferably, the receiving element 7 fully surrounds the sliding disc 6 in the circumferential direction to create an annularly closed clearance space 14.

[0065] The clearance chamber 14 also offers the advantage that the amount of compensating compound does not need to be precisely measured during the manufacture of the axial bearing. Furthermore, the compensating compound pressed into the clearance chamber 14 also bonds the sliding disc 6 to the receiving element 7 in the radial direction, thereby increasing the contact area of ​​the compensating compound between the sliding disc 6 and the receiving element 7 and thus achieving a better and more durable fixation of the sliding disc 6 to the receiving element 7.

[0066] For mounting the axial sliding bearing according to Fig.1. In the manufacture of the turbomachine, it is provided that the sliding disc 6, the support ring 9, and the receiving element 7 are first slid onto the shaft so that at least the receiving element 7 is rotatably connected to the shaft 2. The assembly thus formed is then axially joined with the stationary bearing part 4 and at least one other component of the turbomachine, such as the bearing shield 12, the canned tube, the stator, the motor housing, the impeller 3, and / or the pump housing. The stationary bearing part 4 can already be held in the bearing shield 12 and thus axially joined with the shaft and the rotating bearing components together with the bearing shield 12.

[0067] The hardening compensating compound is placed between the sliding disc 6 and the receiving element 7. This compound can either be injected into the space 8 between the sliding disc 6 and the receiving element 7 after axial assembly, or applied to the sliding disc 6, the support ring 9, and / or the receiving element 7 before axial assembly, with axial sliding onto the shaft 2 then following. During axial assembly with the stationary bearing part 4, the sliding disc 6 is pressed against the support ring 9 by the stationary bearing part 4 under the application of an assembly force, thereby bonding it to the support ring. This ensures that the sliding disc 6 is aligned parallel to the end face of the stationary bearing part 4 and any angular misalignment is compensated for.

[0068] The assembly force is applied to shaft 2 and / or the stationary bearing part 4 until the compensating compound has hardened, so that the position and orientation of the sliding disc 6 can no longer change.

[0069] The assembly of the axial sliding bearing 4, 5 according to the invention offers the advantage that angular errors and / or axial manufacturing errors can be easily compensated from the outset, and this does not have to be done during operation by means of elaborately designed, self-compensating bearings.

[0070] The receiving element 7 is preferably connected to the shaft 2 by means of a press fit, wherein the receiving element 7 has a smaller diameter than the shaft 2 and the shaft 2 is pushed onto it. In this way, a permanent, force-fit connection between the receiving element 7 and the shaft 2 is achieved, which retains its position even under strong forces.

[0071] The curing of the leveling compound can be accelerated compared to curing in air. This is achieved, for example, by exposing the axial sliding bearing 4, 5 to a specific minimum temperature and / or UV light.

[0072] By using a self-hardening compensating compound between the sliding disc 6 and the receiving element 7, the inventive method makes it possible to easily compensate for manufacturing defects and to achieve a permanent plane-parallel alignment of the sliding disc 6 to the stationary bearing part 4, thus reducing friction losses and wear.

Claims

[1] Method for assembling an axial sliding bearing (4, 5) in the manufacture of a turbomachine, comprising a stationary bearing part (4) and a rotatable bearing part (5), which has a sliding disk (6) supported on an end face of the stationary bearing part (4) and at least one bearing component (7, 9) provided for rotationally fixed engagement on a shaft (2), wherein the sliding disk (6) and the bearing component (7, 9) are pushed onto the shaft (2) so that the bearing component (7, 9) is rotatably engaged with the shaft (2) and the assembly thus formed is then axially joined with the stationary bearing part (4), characterized by, that a plastically deformable, hardening compensating mass is introduced into an essentially annular space (8, 15, 16) between the sliding disc (6) and the bearing component (7, 9) and the sliding disc (6) is pressed against the bearing component (7, 9) by the stationary bearing part (4) during axial assembly by applying an assembly force, whereby a shape is imprinted on the compensating mass due to the assembly force and the shape of the space (8, 15, 16) and the compensating mass subsequently hardens, so that this imprinted shape is permanent. [2] Method for mounting an axial sliding bearing (4, 5) according to claim 1, characterized by that the assembly force is applied until the leveling compound has solidified. [3] Method for mounting an axial sliding bearing (4, 5) according to one of claims 1 or 2, characterized by, that the axial sliding bearing (4, 5) is exposed to a certain minimum temperature and / or UV light after axial assembly. [4] Axial sliding bearing (4, 5) for a shaft (2) of a turbomachine, in particular a centrifugal pump (1), comprising a stationary bearing part (4) and a rotatable bearing part (5), wherein the rotatable bearing part (5) comprises a sliding disk (6) supported on an end face of the stationary bearing part (4) and at least one bearing component (7, 9) provided for rotationally fixed carriage on the shaft (2), characterized by that it is produced by the method according to one of claims 1 to 3, wherein between the sliding disc (6) and the bearing component (7, 9) there is a substantially annular space (8, 15, 16) which is filled with a compensating compound which is plastically deformable in the processing state and which solidifies there. [5] Axial sliding bearing (4, 5) according to claim 4, characterized by, that the bearing component (7, 9) is a hat-shaped receiving element (7) for the sliding disc (6). [6] Axial sliding bearing (4, 5) according to claim 4, characterized by , that the bearing component (7, 9) is a support ring (9) arranged between the sliding disc (6) and a second bearing component (7) of the rotatable bearing part (5). [7] Axial sliding bearing (4, 5) according to claim 6, characterized by , that the second bearing component (7) is a hat-shaped receiving element (7) for the support ring (9) and the sliding disc (6). [8] Axial sliding bearing (4, 5) according to claim 6 or 7, characterized by , that a first space area (16) lies between the sliding disc (6) and the support ring (9) and a second space area (15), which is filled with a compensating compound that is plastically deformable in the processing state and solidifies there, lies between the support ring (9) and the second bearing component (7). [9] Axial sliding bearing (4, 5) according to any one of claims 4 to 8, characterized by , that the bearing component (7, 9) has a conical or spherical projection (13) on its inner circumference directed towards the sliding disc (6) and the sliding disc (6) has a corresponding chamfer (17) on its inner circumference into which the projection (13) extends at least partially. [10] Axial sliding bearing (4, 5) according to any one of claims 4 to 9, characterized by that the leveling compound is elastic in the solidified state, in particular an elastomer, a silicone, a natural rubber or synthetic rubber. [11] Axial sliding bearing (4, 5) according to any one of claims 4 to 9, characterized by that the leveling compound is inelastic in its hardened state, in particular an epoxy resin or cement-like binder. [12] Axial sliding bearing (4, 5) according to one of claims 6 to 11, characterized by , that the support ring (9) is made of an elastomer. [13] Axial sliding bearing (4, 5) according to any one of claims 4 to 12, characterized by , that the sliding disc (6) and / or the bearing component (7, 9) has at least one clearance space (14) to accommodate excess counterweight or that a clearance space (14) is formed between the sliding disc (6) and the bearing component (7, 9) to accommodate excess counterweight. [14] Axial sliding bearing (4, 5) according to claim 5 or 7, characterized by , that the receiving element (7) of the sliding disc (6) at least partially surrounds the outer circumference in the circumferential direction, wherein the outer diameter of the sliding disc (6) is smaller than the inner diameter of the encompassing part of the receiving element (7). [15] Axial sliding bearing (4, 5) according to claim 14, characterized by that the receiving element (7) completely surrounds the sliding disc (6) in the circumferential direction.

Images