DE102020110360B4 - Bearing arrangement and method for operating a bearing arrangement - Google Patents

Abstract

Bearing arrangement (100) for a twin-screw extruder, consisting of at least one axial bearing (101) mita. a plurality of rolling elements (102), b. a first bearing ring (104) which is arranged to be rotatable about an axis of rotation of a shaft (120) and which has a first raceway (122) for the plurality of rolling elements (102), c. a second bearing ring (106) directed opposite to the first bearing ring (104) for fastening the axial bearing (101) in a bearing mount (108) and for transmitting axial compressive forces (F) to it, the second bearing ring (106) having a second raceway ( 124) for the plurality of rolling elements (102), the rolling elements (102) being arranged between the first bearing ring (104) and the second bearing ring (106), d. a first spacer sleeve (110) which can be arranged on the shaft (120), and wherein the first bearing ring (104) is arranged in or on a first receptacle (114) formed on the first spacer sleeve (110), unde. a second spacer sleeve (112) for resting on the bearing mount (108), and wherein the second bearing ring (106) is arranged in or on a second mount (116) formed on the second spacer sleeve (112), f. wherein a hydraulic cushion (126) with a hydraulic chamber (236) is formed between the first spacer sleeve (110) and the first bearing ring (104) and/or between the second spacer sleeve (112) and the second bearing ring (106), and wherein the hydraulic chamber (236) is hydraulically connected to a hydraulic system (230), g. a circumferential groove (232) being formed in the first spacer sleeve (110) and/or the second spacer sleeve (112) for the hydraulic chamber (236) of the hydraulic cushion (126), h. which is covered in a fluid-tight manner with an expansion plate (234), which is joined to a support on the associated spacer sleeve (110, 112) in a fluid-tight manner and/or is firmly bonded to the latter.

Description

technical field

The present invention relates to a bearing arrangement with at least one axial bearing and a method for operating such a bearing arrangement.

State of the art

Multi-stage axial bearings or axial cylindrical roller bearings, so-called tandem bearings, are currently used for transfer gears in twin-screw extruders with a high power density, such as those used primarily for processing thermoplastics or rubber. With limited radial installation space, tandem bearings can safely absorb high axial forces, so they combine a small outer diameter with a high load rating. Corresponding bearings usually consist of several axial cylindrical roller bearings arranged one behind the other. The power transmission and/or power distribution takes place mechanically via several spacer sleeves, which (should) ensure exactly the same load on the layered axial bearings. The basic idea of axial bearings in a tandem arrangement was developed in 1943 and is in U.S. 2,374,820 A disclosed.

Bearings that have to absorb particularly high axial forces are also used in other areas of application.

So will in the US 2011 / 299 802 A1 discloses a thrust bearing that allows a first structure to rotate relative to a second structure about an axis of rotation while carrying an axial load between the first structure and the second structure. In one embodiment, the thrust bearing includes a first annular bearing race slidably disposed in a first annular recess in the first structure. Additionally, the thrust bearing includes a second annular bearing ring that engages the second structure. The thrust bearing further includes a plurality of circumferentially spaced roller elements disposed axially between the first bearing race and the second bearing race. The roller elements contact the first bearing race and the second bearing race. The first bearing race and the first recess define a first annular fluid cavity positioned axially between the first bearing race and the first structure. The first bearing race rides on a fluid disposed within the first fluid cavity.

DD 67 846 A1 describes an axial bearing with small radial dimensions of the bearings, in particular for adjacent shafts with a small center distance, the axial bearings being supported with their stationary parts on load transmission rings.

The force distribution on the individual bearings of an axial bearing in a tandem arrangement is influenced by the geometry and material properties, in particular strength and elasticity. For exactly the same load, the material properties must ideally be identical and the geometry-influencing production must be highly precise. Under load, the tandem bearings deform until an equilibrium of forces is reached. The smallest differences in material properties and manufacturing tolerances lead to different loads and deformations. In an extreme case, one or more axial bearings could then not carry any load at all and the remaining axial bearings would therefore be subjected to a correspondingly higher load. This increases the risk of bearing damage. In order to meet this challenge, very high demands are usually placed on the accuracy of the bearings with very low tolerances and the design safety factor is also increased. Thus, the use of materials tends to be increased, which means higher weight, higher costs and a need for a larger installation space.

Description of the invention

The object of the present invention is to provide a more cost-effective solution with which the problems presented are minimized.

The object is solved by the subject matter of the independent claims. Advantageous developments of the invention are specified in the dependent claims, the description and the accompanying figures. In particular, the independent claims of a claim category can also be developed analogously to the dependent claims of another claim category.

A bearing arrangement according to the invention has at least one axial bearing. An axial bearing can generally be understood to mean a bearing that absorbs axial forces. The thrust bearing prevents a shaft from being able to perform axial movements. Other common designations for axial bearings are longitudinal bearings, thrust bearings and thrust bearings, with the axial bearing being designed as a roller bearing in the present case. In a roller bearing, the parts that move relative to one another support one another via rolling elements that move with them.

The thrust bearing has a plurality of rolling elements. Furthermore, the axial bearing has a first bearing ring, which is arranged such that it can rotate about an axis of rotation of a shaft, and a second bearing ring, which is directed opposite to the first bearing ring bearing ring. The first bearing ring has a first raceway for the plurality of rolling elements [for receiving the bearing pressures], the second bearing ring has a second raceway for the plurality of rolling elements. The first bearing ring can also be referred to as the inner ring or inner flange, the second bearing ring can also be referred to as the outer ring, outer bearing support ring or outer flange. The second bearing ring is used to fasten the axial bearing in a bearing mount and to transfer axial compressive forces to this bearing mount. The plurality of rolling elements is arranged between the first bearing ring and the second bearing ring. The bearing mount can be designed as a housing.

Furthermore, the axial bearing has a first spacer sleeve, which can be arranged on the shaft, and a second spacer sleeve for contact with the bearing mount. The first bearing ring is arranged in or on a first receptacle formed on the first spacer sleeve. The second bearing ring is arranged in or on a second receptacle formed on the second spacer sleeve. A hydraulic cushion with a hydraulic chamber is formed between the first spacer sleeve and the first bearing ring. Alternatively or additionally, a hydraulic cushion with a hydraulic chamber is formed between the second spacer sleeve and the second bearing ring. One hydraulic chamber or both hydraulic chambers are hydraulically connected to a hydraulic system. A pressure change in the hydraulic system acts directly on the hydraulic chamber, in which the same pressure is present as in the hydraulic system.

The first receptacle has the hydraulic cushion and additionally or alternatively the second receptacle has the hydraulic cushion. Alternatively, the hydraulic cushion is formed as a receptacle.

The pressure in the hydraulic chamber can advantageously be varied by changing the pressure in the hydraulic system. The hydraulic chamber can be elastically and simultaneously or additionally plastically deformed and thereby exert a preload on the associated bearing ring. Due to the deformation of the hydraulic chamber, manufacturing tolerances in the bearing ring and/or spacer sleeve can be compensated for, particularly in the case of hydraulic chambers that are acted upon separately from one another, and a uniform force distribution can be achieved on the bearing supporting the shaft and its components. Ultimately, this leads to less wear and thus a longer service life of the axial bearing. If the hydraulic chambers are connected to each other, manufacturing tolerances and material inhomogeneities are irrelevant.

The first raceway of the first bearing ring can be introduced in such a way that it lies in a plane whose normal to the axis of rotation encloses an angle of between 45° and 90°. The second raceway of the second bearing ring can then be introduced accordingly. Such an arrangement results from the force vectors for absorbing axial forces.

The hydraulic chamber of the hydraulic cushion in the first spacer sleeve and additionally or alternatively the hydraulic chamber of the hydraulic cushion in the second spacer sleeve is formed as a circumferential, fluid-tight covered groove. This creates a hydraulic chamber that runs around the shaft and supports one of the two bearing rings.

The groove, which is covered in a fluid-tight manner, is covered with an expanding metal sheet, which is joined to a support on the associated spacer sleeve in a fluid-tight manner or is connected to it in a material-to-material manner. The expansion plate can thus be joined directly to the associated spacer sleeve, and the support can define an area of the spacer sleeve against which the expansion plate rests. The expansion plate can be designed in such a way that it can be elastically and/or plastically deformed by a fluid in the hydraulic chamber and can thereby exert a force against the associated bearing ring. For this purpose, the expansion sheet metal can have a small wall thickness. The wall thickness of the expanding sheet metal can be between 0.1 and 2.5 mm, for example. The wall thickness of the expanding sheet metal can be less than 1 mm, in particular less than 0.8 mm, in particular less than 0.6 mm. The expansion plate can, for example, be welded for fluid-tight connection.

In an embodiment not according to the invention, the groove covered in a fluid-tight manner can be covered with an annular hydraulic ram, with a seal being arranged between the support of the hydraulic ram on the associated spacer sleeve and the associated spacer sleeve, which seals the hydraulic chamber fluid-tight to the hydraulic ram. In this way, the hydraulic cushion can be formed in a simple assembly/joining process.

The axial bearing can be designed in the manner of an axial cylindrical roller bearing. Cylindrical roller bearings are relatively easy to manufacture and can absorb large forces.

In the hydraulic chamber and additionally or alternatively in the hydraulic system connected hydraulically to the hydraulic chamber, an incompressible fluid medium, ie an incompressible Fluid to be introduced. A fluid whose density does not depend on pressure is said to be incompressible. Conversely, this means that fluids whose density changes, for example due to thermal influences, can be incompressible. Since in practice these effects are usually much smaller than density changes due to pressure changes, a fluid is considered incompressible if the density is constant along each trajectory. Incompressible fluids represent an idealization. If the fluid medium is incompressible or only very slightly compressible, a uniform pressure can easily be generated in the system over the entire system or, to put it another way, a pressure change then also affects the entire hydraulic system (hydraulic system ) the end.

A plurality of hydraulic cushions may be interconnected via the hydraulic system. In this case, the hydraulic system can have pipelines via which the fluid medium is connected directly to the plurality of hydraulic cushions. The hydraulic cushions are then connected to one another analogous to the principle of communicating tubes. In an alternative embodiment, a plurality of hydraulic systems are connected to one another via a control device in such a way that each of the plurality of hydraulic systems is designed with a pressure sensor and the pressure of the fluid medium can be set or regulated via the control device. The same or an equivalent pressure can then be set in each of the plurality of hydraulic systems connected via the control device.

The incompressible fluid medium can be hydraulic oil, water or dust. Hydraulic oil, also commonly referred to as hydraulic fluid, is a fluid that is used to transfer energy (volume flow, pressure) in hydraulic systems. Hydraulic oil can have good lubricating properties, high resistance to aging and high wetting and adhesion properties. Compatibility with seals and freedom from resin and acid is advantageous. Further properties are a low temperature influence on the viscosity (both dynamic and kinematic viscosity), low compressibility and shear stability as well as low foaming.

The incompressible fluid medium can be subjected to a predetermined pressure in an unloaded operating state. In this way, a defined force can be exerted on the bearing ring.

The hydraulic chamber can be connected to the hydraulic system via axial and/or radial and/or oblique bores in the spacer sleeves. The bores can be created inexpensively in terms of production technology and then ultimately form a channel system for the hydraulic system for connecting the at least one hydraulic cushion to the hydraulic system. The channel system can create the hydraulic connection between the hydraulic cushion and the hydraulic system.

The bearing arrangement can be designed as a tandem bearing, for example for a twin-screw extruder. In this way, an efficient and cost-effective bearing for the twin screw extruder can be created. A twin-screw extruder can also be referred to as a twin-screw extruder. A bearing arrangement known as a tandem bearing can be a multi-row axial cylindrical roller bearing that combines a small outside diameter with a high load rating.

Thus, the bearing arrangement can have at least one second axial bearing, which is arranged axially via the spacer sleeves next to the first axial bearing. In this case, the second axial bearing can be designed analogously to the first axial bearing of the bearing arrangement already described. The second axial bearing can have a plurality of (second) rolling bodies, a first bearing ring, a second bearing ring, a first spacer sleeve, a second spacer sleeve and a second hydraulic cushion with a second hydraulic chamber. The first bearing ring of the second thrust bearing is arranged to be rotatable about the axis of rotation of the shaft. The first bearing ring has a first raceway for the plurality of (second) rolling elements of the second thrust bearing. The second bearing ring is directed in the opposite direction to the first bearing ring of the second thrust bearing and is designed to fasten the second thrust bearing in the bearing seat and to transfer the axial compressive forces to the bearing seat. In this case, the second bearing ring of the second axial bearing has a second raceway for the plurality of (second) rolling bodies of the second axial bearing. The plurality of (second) rolling elements of the second thrust bearing is arranged between the first bearing ring of the second thrust bearing and the second bearing ring of the second thrust bearing. The first spacer sleeve can be arranged on the shaft or is arranged on the shaft. The first bearing ring of the second axial bearing is arranged in or on a first receptacle of the second axial bearing formed on the first spacer sleeve of the second axial bearing. The second spacer sleeve rests against the bearing mount. The second bearing ring of the second axial bearing is arranged in or on a second receptacle formed on the second spacer sleeve of the second axial bearing. Between the first spacer sleeve of the second axial bearing and the first bearing ring of the second axial bearing and additionally or alternatively A second hydraulic cushion with a second hydraulic chamber is formed between the second spacer sleeve of the second axial bearing and the second bearing ring of the second axial bearing. The second hydraulic chamber is hydraulically connected to the hydraulic system and additionally or alternatively to the (first) hydraulic chamber of the (first) axial bearing.

The inventive idea can already be implemented with an axial bearing. If a plurality of axial bearings are used, it makes sense to designate the first axial bearing as such and not to start numbering with the second axial bearing. However, if only one axial bearing is used, the designation as the first axial bearing would be confusing, since one would assume a second axial bearing here. Thus, the numbering is only used when the bearing assembly includes a plurality of thrust bearings.

In order to absorb large axial forces, it can be advantageous if the bearing arrangement has a large number of (additional) axial bearings which are each arranged in series axially via the spacer sleeves next to the first axial bearing or the preceding axial bearing. For example, the bearing arrangement can have 3, 4, 6 or 8 thrust bearings. Ultimately, however, any desired number of axial bearings can be implemented in the bearing arrangement. In this way, the bearing arrangement can be adjusted proportionally to the forces to be absorbed. Such a bearing arrangement can also be referred to as a bearing assembly.

In one embodiment, the bearing arrangement can have a measuring device for determining a pressure of the incompressible fluid medium. A load and/or a state of the bearing arrangement can advantageously be determined by a corresponding measuring device. For this purpose, the measuring device can have a sensor device and an evaluation device connected to the sensor device. The sensor device can be set up to convert the pressure of the incompressible fluid medium into an electrical signal. The electrical signal can be an analog signal or a digital signal. If the electrical signal is an analog signal, a current value or a voltage value can represent a pressure value. Analogously, the pressure value can be encoded in a digital signal and represented by it.

The inventive idea can also be implemented in a method for operating a bearing arrangement. The method has a step of mounting a shaft and a step of absorbing axial forces acting on the shaft by means of the bearing arrangement. Thus, the method of operating the bearing assembly is set up for axially loaded applications.

The shaft can also be a hollow shaft. In one embodiment, the hollow shaft can be part of the bearing arrangement and can simply accommodate an axially loaded shaft. In this way, the bearing arrangement can be easily preassembled.

In the absorbing step, axial forces of a twin-screw extruder can be absorbed by means of the bearing arrangement, as has already been described above.

Furthermore, the method can have a step of detecting and a step of determining. In the detection step, the pressure of the incompressible fluid medium can be detected and in the determination step, a load on the bearing arrangement can be determined using the detected pressure. The load provides information about the operating condition of the bearing assembly. When the bearing assembly is used in a twin screw extruder, the load also gives information about the pressure acting on the screw and hence about forces acting in the machine. Load curves can be created over time. Thus, in the detection step, the pressure can be detected over time, in other words a pressure curve can be detected. This can be used to determine the load over time and other process parameters, in particular if the load recorded in this way is combined with other measurement data.

When determining the load, it should be noted that, as already explained above, incompressible fluids represent an idealization that enormously simplifies many calculations with negligible errors. To determine the load on the bearing arrangement, it can be advantageous to take into account the low compressibility of the incompressible fluid medium.

A state of the bearing arrangement such as aging, damage and, additionally or alternatively, an overload can be determined by means of the load determined. This enables predictive maintenance. As a result, costs can be saved since the bearing arrangement does not have to be changed too early, or a change in the bearing arrangement can also be planned in good time in order to avoid downtimes.

In the determination step, an absolute value of the detected pressure, changes in the detected pressure over time, a derivative of the detected pressure over time, or an integral can be evaluated over the sensed pressure over time to determine the condition. In this case, several of the evaluations can also be combined with one another in order to determine the specific state more robustly, to validate it or to be able to make specific statements about the state.

The above explanations regarding the method apply accordingly to the device and vice versa. The measuring device and in particular the evaluation device of the measuring device can be designed in one component or distributed in several components. Furthermore, the measuring device and/or the evaluation device can be integrated into an ASIC or a comparable integrated circuit (μC, FPGA, . . . ). The evaluation device can generally also be understood as a control unit. The evaluation device mentioned here can be designed in particular as a processor unit and/or an at least partially hardwired or logical circuit arrangement for the metrological steps and steps for evaluating the recorded pressure of the method described. Said evaluation device can be or include any type of processor or processor or computer with the necessary peripherals (memory, input/output interfaces, input/output devices, etc.).

character list

• 1 eine Lageranordnung gemäß einem ersten Ausführungsbeispiels der vorliegenden Erfindung;
• 2a eine Hydraulikkammer in einer Schnittdarstellung gemäß einem zweiten Ausführungsbeispiels der vorliegenden Erfindung;
• 2b die in 2a dargestellte Hydraulikkammer in einer um 90° gedrehten Schnittdarstellung gemäß dem zweiten Ausführungsbeispiels der vorliegenden Erfindung;
• 3a einen Ausschnitt einer Lageranordnung in einer Schnittdarstellung gemäß einem dritten Ausführungsbeispiels der vorliegenden Erfindung;
• 3b die in 3a dargestellten Hydraulikkammer in einer um 90° gedrehten Schnittdarstellung gemäß dem dritten Ausführungsbeispiels der vorliegenden Erfindung;
• 4 eine Detaildarstellung der in 3 dargestellten Hydraulikkammer mit einem Expandierblech gemäß dem dritten Ausführungsbeispiels der vorliegenden Erfindung;
• 5 eine Detaildarstellung einer Hydraulikkammer mit einem ringförmigen Hydraulikstempel
• 6 eine Passhülse für ein Hydrauliksystem einer Lageranordnung gemäß einem fünften Ausführungsbeispiels der vorliegenden Erfindung;
• 7a-7c eine Hydraulikkammer mit einem Expandierblech gemäß einem fünften Ausführungsbeispiels der vorliegenden Erfindung;
• 8a-8c Varianten von Lageranordnungen mit zumindest zwei Axiallagern gemäß einem sechsten, siebten und achten Ausführungsbeispiels der vorliegenden Erfindung; und
• 9 ein Ablaufdiagramm eines Verfahrens zum Betreiben einer Lageranordnung gemäß Ausführungsbeispielen der vorliegenden Erfindung.

Such a bearing arrangement will be described in more detail below with reference to the figures. However, the following description is to be regarded as purely exemplary. The invention is determined solely by the subject matter of the claims. An advantageous exemplary embodiment of the invention is explained below with reference to the accompanying figures. Show it:

• 1 a bearing assembly according to a first embodiment of the present invention;
• 2a a hydraulic chamber in a sectional view according to a second embodiment of the present invention;
• 2 B in the 2a hydraulic chamber shown in a 90 ° rotated sectional view according to the second embodiment of the present invention;
• 3a a detail of a bearing assembly in a sectional view according to a third embodiment of the present invention;
• 3b in the 3a illustrated hydraulic chamber in a 90 ° rotated sectional view according to the third embodiment of the present invention;
• 4 a detailed representation of the 3 illustrated hydraulic chamber with an expanding plate according to the third embodiment of the present invention;
• 5 a detailed view of a hydraulic chamber with an annular hydraulic ram
• 6 a fitting sleeve for a hydraulic system of a bearing assembly according to a fifth embodiment of the present invention;
• 7a-7c a hydraulic chamber with an expanding plate according to a fifth embodiment of the present invention;
• 8a-8c Variants of bearing assemblies with at least two axial bearings according to a sixth, seventh and eighth embodiment of the present invention; and
• 9 a flowchart of a method for operating a bearing assembly according to embodiments of the present invention.

The figures are only schematic representations and only serve to explain the invention. Elements that are the same or have the same effect are provided with the same reference symbols throughout.

Detailed description

1 shows a bearing assembly 100 according to a first embodiment of the present invention. The bearing assembly 100 can be used in a twin-screw extruder, not shown here. The bearing assembly 100 has an axial bearing 101 with a plurality of rolling elements 102, of which only one rolling element 102 is shown here. Furthermore, the axial bearing 101 of the bearing arrangement 100 comprises a first bearing ring 104, a second bearing ring 106, a bearing mount 108, a first spacer sleeve 110 and a second spacer sleeve 112. The bearing mount 108 can be designed, for example, as a housing, a hub, or the like . The type of bearing support is not relevant for the idea presented here. A first receptacle 114 for the first bearing ring 104 is formed on the first spacer sleeve 110 and a second receptacle 116 for the second bearing ring 106 is formed on the second spacer sleeve 110 .

The first bearing ring 104 is arranged such that it can rotate about an axis of rotation 118 of a shaft 120 . The first bearing ring 104 has a first raceway 122 for the plurality of rolling elements 102 . The second bearing ring 106 has a second raceway 124 for the plurality of rolling elements 102 . This second track 124 is parallel to the first Raceway 122 is arranged on the first bearing ring 104 . The rolling elements 102 are arranged between the first bearing ring 104 and the second bearing ring 106 . The second bearing ring 106 is located in the spacer sleeve 112. Axial compressive forces F are then conducted into the bearing mount 108 via this spacer sleeve 112. The axial force F or axial compressive force F symbolizes the axial forces acting on the shaft 120 , which are conducted to the bearing mount 108 via the axial bearing 101 .

The first spacer sleeve 110 is arranged on the shaft 120 (and optionally connected to it in a twist-proof manner, since the rolling resistance of the rolling elements is significantly lower than the sliding resistance between the sleeve and, for example, the shaft shoulder). The second spacer sleeve 112 (or the spacer sleeve with the connected channel system of the hydraulic system) rests on the bearing mount 108 and is connected to it in a torsion-proof manner. A first receptacle 114 is formed in or on the first spacer sleeve 110, in or on which the first bearing ring 104 is arranged. The second receptacle, in or on which the second bearing ring 106 is arranged, is formed in or on the second spacer sleeve 112 . A hydraulic cushion (not shown here) with a hydraulic chamber can be formed between the first spacer sleeve 110 and the first bearing ring 104, the hydraulic chamber being hydraulically connected to a hydraulic system. A hydraulic cushion 126 is shown here, which is formed between the second spacer sleeve 112 and the second bearing ring 106 . The hydraulic cushion 126, not shown here, is connected to the hydraulic system mentioned.

A thrust bearing 101 is described in detail here, there are in 1 however, additional spacer sleeves 112, 114 are indicated, which belong to additional thrust bearings. These can be constructed identically. In this way, the axial forces F can be divided among a plurality of axial bearings 101 . The common hydraulic system helps to ensure that all axial bearings 101 are loaded equally, which results in an equilibrium of forces.

2a shows the in 1 already shown second spacer sleeve 112 with the hydraulic cushion 126, which is connected via a pipeline 228 to the hydraulic system 230. The tubing 228 is formed as a bore in the spacer sleeve. The hydraulic system 230 connecting the hydraulic cushions of a plurality of spacer sleeves is also formed as bore(s) in the spacer sleeves 126 . The bores of the individual spacer sleeves 112 are aligned with one another in order to create a continuous system.

To form the hydraulic cushion 126, a circumferential groove 232 is formed in the (second) spacer sleeve 112, which is covered with an expansion plate 234 in a fluid-tight manner. In the exemplary embodiment shown, the expanding sheet metal 234 is a thin metal sheet which can be deformed simply by applying pressure using the hydraulic system 230 . The expansion plate 234 completely covers the circumferential groove 232 and is fluid-tight, for example materially connected to the second spacer sleeve 112 on a support next to the circumferential groove 232, creating a fluid-tight connection between spacer sleeve 112 and expansion plate 234 and a circumferential hydraulic chamber 236 of the hydraulic Cushion 126 is formed.

When the (internal) pressure in the hydraulic chamber 236 is increased via the hydraulic system 230, a force ultimately acts on the expansion plate 234, which is pressed outwards from the perspective of the hydraulic chamber 236 and is deformed accordingly. One has the impression that a pillow is being created. The expansion plate 234 is pressed against the bearing ring 106 arranged there and exerts a prestress on it if a counterforce exists. As a result, any manufacturing tolerances can be compensated and a defined preload can be set.

2 B shows the hydraulic chamber 236 in a side view along section line AA 2a . Here, the circumferential groove 230 and the support for the expansion plate 234 can be seen.

2a and 2 B show a spacer sleeve 112 with hydraulic bores. The expansion plate 234 is joined to the spacer sleeve 112. Advantageously, the expansion sheet 234 is joined in a materially bonded manner in order to also close or seal off the hydraulic system 230 at this point. Advantageously—particularly from a production and cost perspective—the connection between the hydraulic chamber 236 and the channel system of the hydraulic system is made with an inclined bore. The entire hydraulic system is advantageously filled after assembly and after the hydraulic system has been evacuated.

The idea of the bearing arrangement 100 described here is based on the fact that essentially conventional axial bearings can be used which, however, do not have to be highly precise. Each axial bearing 101 rests on a hydraulic cushion 126. The individual hydraulic chambers 236 are connected to one another. A pressure equalization takes place between the individual hydraulic chambers 236. The pressure equalization takes place through a largely incompressible fluid medium after the Principle of communicating tubes. A hydraulic oil is advantageously used for this purpose. However, dust, for example, would also be conceivable. Optionally, the system can be prestressed with pressure, so that the floating bearing is advantageously additionally supported.

Under load, the hydraulic system forces an identical force distribution, since any additional load on one bearing is distributed or compensated directly to the other bearings via the hydraulic system.

In particular exemplary embodiments, the number of stacked axial bearings 101 is virtually unlimited, so that correspondingly scalable high forces can be absorbed with little radial installation space. The use is position-independent and the individual axial bearings 101 can be loaded on both sides.

Optionally, the loading of the entire bearing assembly 100, also referred to as a bearing assembly, is directly possible by measuring the hydraulic pressure. Advantageously, this information can be used to assess the actual force acting on the bearing, for example to monitor the bearing arrangement 100 during operation and/or to detect overloading and/or damage to the bearing arrangement 100 at an early stage and to be able to take appropriate countermeasures.

Such a measurement can already be advantageously implemented on a single axial bearing in order to be able to monitor the bearing and carry out predictive maintenance and the like. This is therefore not only advantageous for tandem bearings, but can also be implemented sensibly with a single axial bearing 101 . An axial bearing 101 with a hydraulic cushion 126 and a pressure sensor connected to it is sufficient for this.

As already shown, the bearing arrangement 101 presented here is suitable for every application (system) in which (high) axial forces—with little radial space—must be absorbed. These include, in particular, twin-screw extruders, but also various single-screw extruders, injection molding machines and machine tools, but also, for example, applications in shipbuilding, turbine construction or mining.

The principle of the hydraulic cushion 126 can be implemented both in the first spacer sleeve 110 arranged on the shaft 120 and in the second spacer sleeve 112 arranged on the bearing mount 108 (or hub or housing). From a technical point of view, implementation in the second spacer sleeve 112 appears to make more sense after the first attempts, but it also depends on the implementability of the hydraulic system 230 . In special cases, a hydraulic system 230 with a hydraulic cushion 126 can also be provided on both sides.

3a and 3b show a detail of a bearing assembly 100 in a further embodiment, wherein 3b shows a side view on section line BB. Instead of a bore (as in the exemplary embodiment shown above) as a channel, the channel (pipeline 228) is in the form of a longitudinal groove. The channel is sealed with a metal sheet using a weld seam. Alternative seals for the channel can also be implemented.

The opposite channel or, in general, further channels are optional, but can in particular simplify filling with a fluid.

4 shows a further representation of the third embodiment. The hydraulic chamber 236 is covered with an expansion plate 234 on which the second bearing ring 106, also referred to as the bearing support ring, rests. The second spacer sleeve 112 generally fulfills the function of a support ring here. The individual hydraulic cushions 126 are connected via external connections (pipes, hoses, or the like).

5 shows a detailed representation of a hydraulic chamber 236 with an annular hydraulic ram 540 in an embodiment not according to the invention. In contrast to the exemplary embodiments shown above, the hydraulic chamber 236 is not covered with an expanding sheet, but with a hydraulic ram 540 which rests with seals 542 on the spacer sleeve 112 or the groove formed therein. In this way, the hydraulic chamber 236 is sealed and the hydraulic plunger 540 can be moved in the direction of the bearing ring (not shown here) to compensate for tolerances etc. The seal between the hydraulic ram 540 and the spacer sleeve 112 is implemented using known principles.

6 shows a fitting sleeve 650 for a hydraulic system 230 of a bearing assembly 100 according to a fifth embodiment of the present invention. If the individual components are manufactured as individual parts, the pipes 228 which are formed in the individual spacer sleeves 112 must also be connected to one another. A fluid-tight connection that withstands the pressure in the hydraulic system 230 must be created. A variant of such a fluid-tight connection is in 6 shown, with a fitting sleeve 650 as a sealing compound tion element in the two separately formed pipes 238 is added. For this purpose, the diameter of the pipelines 238 is expanded in the region of the fitting sleeve 650 with an expanding bore 652, with a press fit being provided between the fitting sleeve 650 and the bore 652 in order to produce a fluid-tight connection. The fitting sleeve 650 could also be glued in to improve the seal, or alternatively an additional seal could be provided.

7a - 7c shows a hydraulic chamber with an expansion plate 234 according to a fifth embodiment of the present invention. Differently preformed expansion plates 234 are shown as an example. While 7a shows a flat expansion plate 234, the hydraulic chamber 236 is in 7b and 7c covered with a preformed expansion sheet metal 234. Manufacturing advantages can thus be used. Under internal pressure, each expander sheet 234 should bulge outward

The bearing arrangement 100 described here can optionally be combined with radial bearings 860. In order to maintain the idea that a plurality of axial bearings 101 create an even distribution of force over the plurality of bearings via the hydraulic cushions 126, it is important that the hydraulic system 230 of the individual axial bearings 101 is connected to one another even when additional radial bearings 860 are used is. In 8b the radial bearing 860 is arranged in such a way that the hydraulic system 230 is connected to one another between the two axial bearings 101 without any further changes. In 8a a bypass 862 is provided on the radial bearing 860 .

In other words, the pipeline 228 can be implemented, for example, through a bore or through an external channel. The outer channel would then have to be sealed airtight and pressure-tight. An internal channel is also conceivable, but seems less advantageous. Alternatively, each spacer sleeve can also have hydraulic connections and the coupling can take place via hoses and pipes, or, as described, also electrically via a corresponding control and regulation device. The individual ducts or pipelines 228 must be connected or joined at the end faces, this can be achieved with a material connection - for example welding, soldering, gluing,... - with a form fit - for example fitting sleeves, fitting geometry,... - or with a force fit, for example union nuts, screw connections be, whereby a combination is also possible.

The expansion plate 234 can be flat, convex or concave (unfavorable). Sheet metal may also not be required. It depends on the expanding area. A tube in the form of a ring with a hydraulic connection on which the axial bearing lies is also conceivable.

8c shows a possible embodiment with a bearing arrangement 100 acting on both sides, by means of a second axial bearing 101, which is arranged mirror-inverted to the first axial bearing 101 and can thereby absorb forces acting axially in the opposite direction. Depending on the design, two separate or one jointly acting hydraulic system 230 can be provided here. The hydraulic system 230 of the first thrust bearing 101 and the hydraulic system 230 of the second thrust bearing 101 can be connected via a connecting element 864 or alternatively be separate. A spacer piece 866 can optionally be provided between the spacer sleeves 110 .

The force absorption can therefore not only take place in one direction, but also in two directions. The hydraulic system for absorbing the forces on one side can be connected to the hydraulic system on the other side. However, the connection is not necessary. Both variants have corresponding advantages and disadvantages.

the inside 8a The bypass shown can also be implemented electronically via the control of the hydraulic system 230, if both systems can be regulated via a pressure sensor, the same pressure can be regulated in both (or more) systems without the systems being hydraulically connected to one another. In large systems in particular, this can bring advantages, since the individual hydraulic systems are smaller in size and compression of the hydraulic fluid can therefore have less of an impact.

The bearing assembly 100 shown and described herein has several advantages. In this way, costs can be reduced compared to conventional tandem bearings. The service life tends to increase due to the even loading of the individual axial bearings. This also reduces wear.

The bearing arrangement 100 can be monitored by an optional pressure measurement, as a result of which the service life can be increased and downtimes can be reduced.

The lower masses compared to conventional, larger axial bearings have a positive effect on assembly and disassembly, material costs and storage costs.

9 FIG. 1 shows a flowchart of a method for operating a bearing arrangement 100 according to exemplary embodiments of the present invention Invention. The method has a step S1 of mounting a shaft and a step S2 of absorbing axial forces acting on the shaft by means of the bearing arrangement. The shaft can be a hollow shaft. The method is particularly suitable for axially loaded applications.

Optionally, in step 52 of absorbing, axial forces of a twin-screw extruder are absorbed by means of the bearing arrangement.

In one exemplary embodiment, the method has a step S3 of detecting the pressure of the incompressible fluid medium and a step S4 of determining a load on the bearing assembly using the detected pressure. The load determined in this way is ultimately information about the operating status and thus, when used in a twin-screw extruder, for example, the pressure acting on the screw, i.e. the force acting; in the case of a detection and determination over a period of time, load curves can thus be determined over time.

Optionally, the load can be recorded over time in step S3 of recording. A state of the bearing arrangement, such as aging and/or damage and/or overloading, in particular for predictive maintenance, can be determined by means of the load determined.

Optionally, in step S4 of determination, an absolute value of the detected pressure and/or changes over time in the detected pressure and/or an integral over the detected pressure over time are evaluated in order to determine the state.

Reference List

100

bearing arrangement

101

thrust bearing

102

rolling elements

104

first bearing ring

106

second bearing ring

108

stock pick-up

110

first spacer

112

second spacer sleeve

114

first shot

116

second recording

118

axis of rotation

120

wave

122

first career

124

second career

126

hydraulic cushion

228

pipeline

230

Hydraulic system, hydraulic system

232

circumferential groove

234

expanding sheet

236

hydraulic chamber

540

hydraulic ram

542

poetry

650

fitting sleeve

652

drilling

860

radial bearing

862

bypass

864

fastener

866

spacer

f

axial force

Claims (15)

Bearing arrangement (100) for a twin-screw extruder, consisting of at least one axial bearing (101) with a. a plurality of rolling elements (102), b. a first bearing ring (104) which is arranged to be rotatable about an axis of rotation of a shaft (120) and which has a first raceway (122) for the plurality of rolling elements (102), c. a second bearing ring (106) directed opposite to the first bearing ring (104) for fastening the axial bearing (101) in a bearing mount (108) and for transmitting axial compressive forces (F) to it, the second bearing ring (106) having a second raceway ( 124) for the plurality of rolling elements (102), the rolling elements (102) being arranged between the first bearing ring (104) and the second bearing ring (106), d. a first spacer sleeve (110) which can be arranged on the shaft (120), and wherein the first bearing ring (104) is arranged in or on a first receptacle (114) formed on the first spacer sleeve (110), and e. a second spacer sleeve (112) to rest on the bearing mount (108), and wherein the second bearing ring (106) is arranged in or on a second mount (116) formed on the second spacer sleeve (112), f. wherein between the first spacer sleeve (110) and the first bearing ring (104) and/or between the second spacer sleeve (112) and the second bearing ring (106), a hydraulic cushion (126) with a hydraulic chamber (236) is formed, and the hydraulic chamber (236) is hydraulic with a hydraulic system (230) is connected, g. a circumferential groove (232) being formed in the first spacer sleeve (110) and/or the second spacer sleeve (112) for the hydraulic chamber (236) of the hydraulic cushion (126), h. which is covered in a fluid-tight manner with an expansion plate (234), which is joined to a support on the associated spacer sleeve (110, 112) in a fluid-tight manner and/or is firmly bonded to the latter. Bearing arrangement (100) according to the preceding claim, wherein the axial bearing (101) is designed in the manner of an axial cylindrical roller bearing. Bearing arrangement (100) according to one of the preceding claims, with an incompressible fluid medium in the hydraulic chamber (236) and/or the hydraulic system (230) hydraulically connected to the hydraulic chamber (236). Bearing arrangement (100) after claim 3 , wherein the incompressible fluid medium is a hydraulic oil and/or water and/or dust. Bearing arrangement (100) according to one of claims 3 or 4 , wherein the incompressible fluid medium is subjected to a predetermined pressure in an unloaded operating state. Bearing arrangement (100) according to one of the preceding claims, wherein the hydraulic chamber (236) is connected to the hydraulic system (230) via axial and/or radial and/or oblique bores in the spacer sleeves (110, 112). Bearing arrangement (100) according to one of the preceding claims, with at least one second thrust bearing (101) which is arranged axially via the spacer sleeves (110, 112) next to the first thrust bearing (101), the second thrust bearing (101) comprising: a. a plurality of rolling elements (102), b. a first bearing ring (104) which is arranged to be rotatable about the axis of rotation of the shaft (120) and which has a first raceway (122) for the plurality of rolling bodies (102) of the second axial bearing (101), c. a second bearing ring (106) directed opposite to the first bearing ring (104) of the second axial bearing (101) for fastening the second axial bearing (101) in the bearing mount (108) and for transmitting the axial compressive forces (F) to it, the second Bearing ring (106) of the second thrust bearing (101) has a second raceway (124) for the plurality of rolling elements (102) of the second thrust bearing (101), the plurality of rolling elements (102) of the second thrust bearing (101) between the first bearing ring (104) of the second axial bearing (101) and the second bearing ring (106) of the second axial bearing (101) are arranged, i.e. a first spacer sleeve (110) which can be arranged on the shaft (120), and wherein the first bearing ring (104) of the second axial bearing (101) is formed in or on a first spacer sleeve (110) of the second axial bearing (101). Recording (114) of the second axial bearing (101) is arranged, and e. a second spacer sleeve (112) for contact with the bearing mount (108), and wherein the second bearing ring (106) of the second axial bearing (101) is formed in or on a second mount (112) of the second axial bearing (101) 116) is arranged, f. between the first spacer sleeve (110) of the second axial bearing (101) and the first bearing ring (104) of the second axial bearing (101) and/or between the second spacer sleeve (112) of the second axial bearing (101) and the second bearing ring ( 106) of the second axial bearing (101), a second hydraulic cushion (126) is formed with a second hydraulic chamber (236), and the second hydraulic chamber (236) is hydraulically connected to the hydraulic system (230) and/or the hydraulic chamber (230) of the first Axial bearing (101) is connected. Bearing arrangement (100) according to one of the preceding claims, with a plurality of further axial bearings (101) which are arranged in series in each case axially via the spacer sleeves (110, 112) next to the first axial bearing (101) or the preceding axial bearing (101). Bearing arrangement (100) according to one of the preceding claims, with a measuring device for determining the pressure of the incompressible fluid medium. Method for operating a bearing arrangement (100), with a step (S1) of mounting a shaft (120) and a step (S2) of absorbing axial forces (F) acting on the shaft (120) by means of the bearing arrangement (100). any of the preceding claims. Method according to the preceding claim, in which, in step (S2), axial forces of a twin-screw extruder are absorbed by means of the bearing arrangement. Procedure according to one of Claims 10 until 11 with a step (S3) of detecting the pressure of the incompressible fluid medium and with a step (S4) of determining a load on the bearing arrangement using the detected pressure. Method according to the preceding claim, wherein in step (S3) of recording the load is recorded over time. Procedure according to one of Claims 12 until 13 , A state of the bearing arrangement (100) such as aging and/or damage and/or overloading, in particular for predictive maintenance, being determined by means of the load determined. Procedure according to one of Claims 12 until 14 , wherein in the step (S4) of determining an absolute value of the detected pressure and/or changes over time in the detected pressure and/or an integral over the detected pressure over time is evaluated in order to determine the state.

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