Bearing assembly

Abstract

The invention relates to a bearing assembly (1) for mounting a rotating machine part, e.g. a shaft (2), comprising at least one rolling bearing (3), one or more inner seals (8) for forming an inner sealing chamber containing the rolling elements of the rolling bearing (3), a lubricant inlet (11) leading into the inner sealing chamber, a bearing housing (4) which receives the rolling bearing (3), one or more outer seals (9) for forming an outer sealing chamber containing the inner sealing chamber, and at least one lubricant outlet (13) leading out of the outer sealing chamber. The bearing assembly is characterized in that a lubricant circuit is provided between the lubricant inlet (11) and the lubricant outlet (13) in that the lubricant exits the inner sealing chamber in the region of the one or more inner seals (8) and enters the outer sealing chamber.

Description

[0001] Bearing arrangement

[0002] Description

[0003] The invention relates to a bearing arrangement of a rotating machine part, e.g. a shaft, with at least one rolling bearing, one or more inner seals for forming an inner sealing chamber containing the rolling elements of the rolling bearing and a lubricant inlet to the inner sealing chamber, as well as a bearing housing accommodating the rolling bearing, one or more outer seals for forming an outer sealing chamber containing the inner sealing chamber, and at least one lubricant outlet from the outer sealing chamber.

[0004] The lubrication of rolling bearings is particularly important. Lubrication can be achieved using greases, oils, or, in special applications, solid lubricants. Grease lubrication does not require any special equipment, and sealed rolling bearings can be used. Furthermore, a distinction is made within grease lubrication between rolling bearings greased for life or service life and rolling bearings with relubrication. During relubrication, the new grease pressed into the rolling bearing generally forces out the used grease, as well as any contaminants that may have penetrated the sealed rolling element space. This material must be disposed of accordingly, making this type of lubrication a loss-based lubrication system.

[0005] Oil lubrication has the advantage over grease lubrication, for example, that it also allows for heat dissipation and thus cooling. With oil lubrication, a distinction is made between oil bath lubrication with or without an oil feed ring and circulating oil or oil injection lubrication. These systems use unsealed, open rolling bearings arranged in a bearing housing that acts as an outer housing, sealing off the rotating machine part and forming an oil chamber for the oil lubrication of the rolling bearing. Circulating oil lubrication, in particular, allows contaminants that have entered the rolling bearing to be transported out of the rolling bearing by the circulating oil and filtered out in the circulating oil. On the other hand, due to the open bearing design, a significant amount of oil flow is required to achieve a certain lubricating effect in the rolling bearing.

[0006] Based on the prior art known from practice, the object of the invention is to provide a bearing arrangement for the rotatable mounting of a rotating machine part, e.g. a shaft, which is characterized by improved lubrication.

[0007] To achieve this object, the invention teaches a bearing arrangement having the features of claim 1.

[0008] In a generic bearing arrangement of the type described above, the invention proposes that a lubricant circulation is provided between the lubricant inlet and the lubricant outlet via an exit of the lubricant from the inner sealing space in the region of one or more inner seals into the outer sealing space.

[0009] In addition to the bearing housing and the rolling bearing, the bearing assembly can also comprise the rotatable machine part, e.g., a shaft. This machine part is rotatably mounted with the rolling bearing in the bearing housing, while the bearing housing can be fixedly attached to another machine part, e.g., to a machine frame or another machine component. This naturally includes not only embodiments in which the bearing inner ring of the rolling bearing is non-rotatably connected to the shaft intended for rotation or is formed by it, but also embodiments in which the bearing outer ring, or the component forming it, is intended for rotation and the bearing inner ring is stationary. Furthermore, the bearing assembly comprises the circulating lubrication system according to the invention.

[0010] Compared to grease lubrication with relubrication, the invention is particularly advantageous in that it eliminates lubricant loss. This eliminates the costs of procuring and disposing of grease for bearing lubrication. The system is also environmentally friendly because it eliminates the need for grease replacement.

[0011] Compared to conventional circulating lubrication systems with open rolling bearings, the invention, particularly due to the presence of internal seals to achieve the same lubricating effect as conventional circulating lubrication, particularly advantageously requires significantly lower circulating quantities of the lubricant or substance, particularly a liquid lubricant or lubricating oil (hereinafter also referred to as oil). Otherwise, however, the advantages of conventional circulating oil lubrication are essentially retained.

[0012] The oil is circulated, but using a rolling bearing with internal seals, for example in the form of a sealed rolling bearing or a rolling bearing with integrated seals, so that the oil is preferably supplied to the sealed rolling bearing via an oil inlet and drained from the bearing housing (as the outer housing) via an oil outlet. For this purpose, the oil inlet can flow into the sealed rolling bearing, e.g., via at least one inlet opening integrated into a bearing ring, e.g., the outer ring. The oil then escapes from the inner sealing chamber formed by the internal seals, which contains the rolling elements, in the area of ​​said seals, in particular via their dynamic sealing point.When the inner seal is designed as a gap seal, the dynamic sealing point is its sealing gap, and when it is designed as a contact seal, it is the contact area that slides during operation, for example in the area of ​​its elastic sealing lip. Above a certain, predefined oil pressure in the inner sealing chamber, for which the seal is designed accordingly, leaks occur and oil can escape. With a gap seal, this is controlled by the gap design. After escaping from the inner sealing chamber, the oil flows, for example, into an outer sealing chamber formed by the bearing housing, e.g. into an oil receiving chamber, from where it continues its path in the oil circulation, for example via a drain opening integrated into the bearing housing or outer housing.The oil receiving chamber is designed in particular in such a way that no impurities, for example those extracted from the rolling bearing or otherwise entering the housing, collect there in a sump-like manner, but are carried along by the oil circulation and filtered out in the oil circulation.

[0013] The oil is then fed into the interior of the rolling bearing. From there it passes through the inner seal into the outer housing (i.e. into its receiving space) and is from there returned through the drain opening. The rolling bearing is preferably supplied with oil via the inlet to such an extent that the oil constantly escapes from the sealed rolling bearing through the inner seal and is consequently forced into circulation. In comparison to conventional oil circulation lubrication systems (with open bearings), the invention allows the use of small amounts of oil to achieve the same lubricating effect. The relatively small interior of the rolling bearing is, so to speak, well filled with oil, whereas the circulation requires very small amounts of oil. This means that the entire system for oil circulation lubrication, such as piping, pump, etc., can be implemented with particular advantage and is therefore more cost-effective.

[0014] Furthermore, for proper operation, it may be necessary to equip the housing with ventilation.

[0015] A particular advantage is the ability to monitor the circulating oil. While this is known in principle, the invention implements it in combination with a sealed, oil-lubricated rolling bearing, which simultaneously prevents dirt from entering the bearing.

[0016] In a particularly preferred embodiment, the lubricant circulation or the devices for the circulation lubrication are equipped with or connected to a computer, which can be designed, for example, as a diagnostic computer (i.e., analysis computer) and enables optimal monitoring and / or control of the oil circulation, including the option of oil analysis and thus improved system monitoring. It is therefore expedient to also equip the lubricant circulation, i.e., the circulation lubrication device, with one or more sensors for analyzing the oil circulated or returned via the oil outlet (i.e., oil return) and / or the oil supplied to the oil inlet, whereby these sensors are preferably connected to the diagnostic computer.

[0017] For example, at least one temperature sensor can be used as a sensor to monitor the oil temperature. Although the viscosity can also be determined or calculated using the green oil viscosity of the oil, the VI index, and the oil temperature, a viscosity sensor can also be used as an alternative or in addition to the sensor to determine and subsequently monitor the viscosity and thus the quality of the oil. Furthermore, at least one contamination sensor (or purity sensor) and / or a material sensor can be used as an alternative or in addition to the sensor, i.e. one or more sensors that can detect contamination, foreign substances, or foreign particles, e.g. regardless of viscosity, and can preferably also analyze them in a material-sensitive manner. This way, contamination of the lubricant can be detected. Furthermore, particles in the oil can be detected in a material-sensitive manner. For example, the sensor canbe designed in such a way that mineral particles and / or metallic particles can be detected or differentiated from one another. This can also provide information about the function of the seals used, e.g., external seals and / or internal seals. While metallic particles, for example, can originate from the bearing components themselves, mineral particles can have penetrated the outer casing from the outside via the system and indicate damage to the seals or even damage to the system itself.

[0018] Optionally, the lubricant circulation system, i.e., the circulation system, can be equipped with at least one filter for the oil conveyed in the circulation system. For example, one (or more) filters can be integrated into the return line(s) between the oil outlet and the sensors (or conveying system) and / or into the oil supply line between the sensors (or the conveying direction) and the oil inlet. The oil circulation lubrication system for the bearing thus offers the option of filtering in the inlet and / or return line, or alternatively, via a bypass or a tank. A water separator can be integrated as an option.

[0019] Overall, the design according to the invention enables optimal monitoring of the sealing arrangement and, optionally, also improved monitoring of the machines and systems into which the sealing arrangement is integrated. The described analysis of the circulating oil allows the bearing and the sealing system to be monitored, and conclusions can also be drawn about the function of the machine or system. The improved and controlled lubrication conditions, e.g., through temperature monitoring, purity monitoring, and filtration, result in longer bearing service lives. During computer data analysis, artificial intelligence or machine learning methods can be used for further optimization. The invention opens up optimized possibilities for remanufacturing the rolling bearing, particularly with regard to timing and general suitability.Sustainability is further improved, especially compared to a new purchase.

[0020] The oil analysis (e.g. as online analysis) enables temperature monitoring, a purity class determination and / or a determination of the type of contamination using the sensors described.

[0021] Optionally, a temperature control system, such as a cooling and / or heating system, can be integrated into the lubricant circulation or circulation system. This allows the viscosity of the circulating oil to be adjusted, preferably based on measured viscosity values. Cooling and / or heating preferably occurs in the inlet. This allows, among other things, optimal lubrication conditions to be set for the respective operating state.

[0022] Basically, according to the invention, circulating lubrication is used, i.e., the oil is forced into circulation. Since – compared to conventional circulating oil lubrication with open or unsealed bearings – a lower exchange or circulation volume is preferably realized, the circulating oil will generally be used only to a limited extent for cooling the bearing, and additional cooling measures will be provided if necessary. However, the invention also encompasses embodiments in which the circulating oil is also used for cooling the bearing. In particular, cooling the circulating oil with a cooling unit can be advantageous for this purpose in order to dissipate process and bearing heat. However, cooling may be useful or necessary simply due to the viscosity regulation or control described above.

[0023] In an advantageous embodiment, the rolling bearing is designed as a spherical roller bearing. The inner and outer rings of the spherical roller bearing are rotatable relative to one another with the interposition of rolling elements. The rolling elements in a spherical roller bearing are generally two rows of spherical rollers whose axes are inclined relative to the axis of rotation of the bearing. The raceway of the outer ring is generally hollow. The spherical roller bearing not only allows rotation of the inner ring relative to the outer ring, but also tilting within certain limits. This means that spherical roller bearings are particularly used for supporting machine parts, e.g. shafts, which are not only mounted in a rotating manner but also in an angularly movable manner, e.g. in a machine frame. Spherical roller bearings are also used, for example, when misalignment or deflection of the shaft must be compensated or prevented.should be permitted, with the rollers oscillating in the outer ring raceway. According to the invention, the spherical roller bearing is sealed with seals, which are referred to as internal seals and which seal the bearing directly, for example between the inner ring and outer ring. These internal seals can be designed in a basically known manner as gap seals as already described above or as contact seals, e.g. as sealing washers. It is crucial that the internal seals allow controlled oil outflow as described above. This offers the possibility of implementing circulating lubrication even with a sealed bearing. Despite the sealed design, the oil is circulated in forced circulation, so that the advantages of circulating oil lubrication are achieved while at the same time providing optimal protection for the spherical roller bearing against contamination.Bearing lubrication is loss-free and completely grease-free, making it cost-effective and economical. Longer bearing service life is achieved, which is further optimized through appropriate monitoring. At the same time, despite the bearing seal, circulating oil lubrication enables optimized system monitoring by allowing analysis of the circulating oil.

[0024] Of course, other types of rolling bearings are also used in other designs. Particularly worth mentioning are double-row tapered roller bearings in an X or O arrangement, but also other multi-row roller bearings, such as cylindrical roller bearings. With these types of rolling bearings, lubricant openings between the rows of rolling elements are often already advantageous. However, other types of rolling bearings can also be used, such as single-row roller bearings and ball bearings, in which case special attention may need to be paid to oil supply openings, or even single-row rolling bearings grouped together to form multi-row arrangements, where the oil supply takes place, so to speak, between the individual bearings, which may then only be sealed on one side.

[0025] The bearing arrangement according to the invention is preferably used to support a rotating machine part, e.g. a shaft, wherein the bearing housing surrounds the rolling bearing as an outer housing and is sealed against the machine part, e.g. against the shaft, by means of one or more outer seals, which can also be referred to as housing seals, so that the space between the bearing housing and the rolling bearing arranged therein forms an oil receiving space for the oil escaping from the spherical roller bearing through the inner seals. The outer seals can also be designed as sliding seals that are fastened to the outer housing. In this case, it can be advantageous to design the outer seals as air barrier seals. If sealing with barrier grease is omitted, the entire process can be carried out completely without grease. Of course, a labyrinth seal that is only initially greased can also be used.

[0026] The invention is explained in more detail below with reference to a drawing, which represents only one exemplary embodiment. The sole figure shows a simplified vertical section through a bearing arrangement according to the invention.

[0027] The figure shows a bearing arrangement 1 which has a rotating machine part, e.g. a shaft 2, a spherical roller bearing 3 and a bearing housing / outer housing 4. The shaft 2 is rotatably mounted with the spherical roller bearing 3 in the bearing housing / outer housing 4, which is fixedly attached, for example, to a machine component, e.g. a machine frame. The spherical roller bearing 3 has an outer ring 5 (as a bearing ring) fastened to the outer housing 4 and an inner ring 6 which is fastened to the rotatable machine part, i.e. to the shaft 2, and which can rotate and at the same time tilt relative to the outer ring 5. The rolling elements 7 rotate between the inner ring 5 and the outer ring 6, wherein in the exemplary embodiment two rows of spherical rollers are provided, the axes of which are inclined relative to the axis of rotation D of the bearing.

[0028] In the exemplary embodiment, the spherical roller bearing 3 is designed as a sealed, oil-lubricated spherical roller bearing with internal seals 8 between the outer ring 5 and inner ring 6, forming an internal sealing chamber that accommodates the rolling elements 7. The internal seals 8 in the exemplary embodiment are implemented as disc seals that are clipped into corresponding recesses on the outer ring 5 to form a static seal. Their elastomer sealing lip rests against the inner ring 6 in a sliding, sealing manner, forming the dynamic sealing point.

[0029] The shaft 2 is mounted in the manner described with the spherical roller bearing 3 in the bearing housing 4 as an outer housing, wherein the bearing housing 4 is sealed against the shaft 2 by means of external seals 9, so that the outer housing 4 forms an outer sealing chamber which, at least in some areas, forms an oil receiving chamber 10 for the oil escaping from the spherical roller bearing 3 via the dynamic sealing points of the internal seals 8 above a certain oil pressure.

[0030] Furthermore, it can be seen in the figure that the bearing arrangement 1 is equipped with a circulating lubrication device. For this purpose, an oil inlet 11 flows into the sealed spherical roller bearing 3 via an inlet opening 12, which extends through the outer housing 4 at its upper apex and then opens into an annular circumferential groove 23 on the outer surface of the outer ring 5, from which several, for example three, lubrication openings 24 distributed in the circumferential direction and radially penetrating the outer ring 5 open between the two rows of spherical rollers. In other embodiments, the groove 23 can of course also be realized on the inner surface of the outer housing 4 instead of on the outer ring 5, or such a groove 23 can be dispensed with entirely, for example by simply extending the inlet opening 12, so to speak, into the interior of the bearing with a lubrication opening 24 in the outer ring 5.Furthermore, an oil drain 13 is realized, which is connected to the outer and consequently the oil receiving space 10, namely by one or more drain openings 14 integrated into the outer housing 4. In the exemplary embodiment, two drain openings 14 are provided, which are arranged on both sides of the spherical roller bearing 3 at the lower apex, which advantageously prevents the formation of an oil sump, which may contain impurities.

[0031] The lubricant circulation is equipped with or connected to a circulating lubrication device having at least one oil conveying device 15, e.g., a pump, with which the oil is circulated through the bearing arrangement 3. The oil conveying device 15 conveys the oil via the inlet line 16 and the oil inlet 11 into the spherical roller bearing 3, i.e., into the inner sealing chamber. From there, it passes through the inner seals 8 into the outer sealing chamber and consequently into the oil collecting chamber 10 outside the sealed spherical roller bearing 3 and inside the outer housing 4. From there, it is transported to the conveying device 15 via the outlet openings 14 and the return lines 17, particularly as part of a pressureless return.

[0032] The circulating lubrication system is also equipped with one or more filters 18 (only indicated) for the circulating oil. For example, a filter 18 is integrated into each of the two oil return lines 16. Optionally or alternatively, a filter 18 can be implemented after the return lines 17 are joined, in the oil supply line 16, or in a bypass (not shown). In one embodiment, the delivery device 15 and / or the filters 18 can also include devices for regulating or controlling the oil temperature and / or a water separator.

[0033] The figure also shows that the circulating lubrication system is equipped with one or more sensors 19, 20, 21 that measure and monitor the condition and properties of the circulating oil. A temperature sensor 19, a viscosity sensor 20, and a sensor 21 for determining cleanliness levels are shown as examples. These sensors are connected to a diagnostic computer 22, which is also shown only in a simplified schematic. In particular, the measuring and monitoring task assigned to sensor 21 may also determine the arrangement of filters 18, particularly whether filters 18 are provided exclusively upstream or downstream of sensor 21 in the direction of oil flow in order to measure and monitor the oil before or after filtering; however, multiple sensors 21 arranged upstream and downstream of filters 18 may also be used to measure and monitor both.

[0034] The figure shows an overall design in a completely grease-free configuration with a recirculating oil lubrication system, which offers optimized monitoring and analysis options, including seal monitoring. Compared to conventional recirculating lubrication systems with larger oil volumes, it also enables simpler and more precise oil diagnostics, allowing for more precise information on lubricant film thickness, contamination levels, etc., and thus also enables accurate bearing service life predictions and predictions regarding replacement and remanufacturing times.

Claims

Patent claims 1. Bearing arrangement (1) for supporting a rotating machine part, e.g. a shaft (2), with at least one rolling bearing (3), one or more internal seals (8) for forming an internal sealing chamber containing the rolling elements of the rolling bearing (3) and a lubricant inlet (11) to the internal sealing chamber, as well as a bearing housing (4) accommodating the rolling bearing (3), one or more external seals (9) for forming an external sealing chamber containing the internal sealing chamber, and at least one lubricant outlet (13) from the external sealing chamber, characterized in that a lubricant circulation is provided between the lubricant inlet (11) and the lubricant outlet (13) via an exit of the lubricant from the internal sealing chamber in the region of the one or more internal seals (8) into the external sealing chamber.

2. Bearing arrangement according to claim 1, characterized in that the lubricant inlet (11) comprises in particular a plurality of lubrication holes (12) distributed in the circumferential direction and radially penetrating a bearing ring of the rolling bearing (3), wherein the lubrication holes (12) can be connected on the supply side via a groove (23) radially encircling the bearing ring.

3. Bearing arrangement according to claim 1 or 2, characterized in that the lubricant outlet (13) is connected to a lubricant receiving space (10) within the bearing housing (4), e.g. via a drain opening (14) integrated into the bearing housing (4).

4. Bearing arrangement according to one of claims 1 to 3, characterized in that the lubricant circulation is provided with at least one filter (18), a water separator and / or a device for regulating or controlling the temperature for the circulating lubricant.

5. Bearing arrangement according to one of claims 1 to 4, characterized in that the lubricant circulation is equipped with a computer (22), e.g. a diagnostic computer.

6. Bearing arrangement according to one of claims 1 to 5, characterized in that the lubricant circulation is equipped with one or more sensors (19, 20, 21) for analyzing the lubricant circulated or returned via the lubricant outlet and / or supplied to the lubricant inlet, wherein the sensor(s) (19, 20, 21) are preferably connected to the computer (22).

7. Bearing arrangement according to claim 6, characterized in that at least one sensor is designed as a temperature sensor (19).

8. Bearing arrangement according to claim 6 or 7, characterized in that at least one sensor is designed as a viscosity sensor (20).

9. Bearing arrangement according to one of claims 6 to 8, characterized in that at least one sensor is designed as a contamination sensor (21) and / or material sensor.

10. Bearing arrangement according to one of claims 1 to 9, with a machine part, e.g. a shaft (2), which is rotatably mounted with the rolling bearing (3) in the bearing housing (4), wherein preferably an inner ring (6) of the rolling bearing (3) is connected to the machine part, e.g. the shaft (2).

11. Bearing arrangement according to one of the preceding claims, wherein the lubricant is provided for escaping from the inner sealing space via the dynamic sealing point of the one or more inner seals (8), wherein the dynamic sealing point is the sealing gap in the case of a gap seal and the contact area of ​​the contact seal, in particular the elastic sealing lip thereof, which is in contact during operation and which slides against the seal.

12. Bearing arrangement according to claim 11, characterized in that the sealing gap of the inner seal (8) designed as a gap seal or a contact pressure of the inner seals (8) designed as a contact seal is set or adjustable, e.g. depending on one or more parameters of the circulating lubrication, e.g. depending on the lubricant pressure, a maximum lubricant filling of the inner sealing space, a predetermined lubricant flow or the like.

13. Bearing arrangement according to one of the preceding claims, wherein the one or more inner seals (8) are arranged to act between an inner and outer ring of the rolling bearing (3), as seals integrated into the rolling bearing (3), in particular with the possibility of fastening directly in or on one of the rolling bearing rings and / or not or hardly protruding beyond the outer dimension of a comparable unsealed rolling bearing and / or are arranged directly or indirectly adjacent to the actual rolling bearing (3).

14. Bearing arrangement according to one of claims 1 to 13, characterized in that the outer seals (9) comprise sliding seals, sealing air seals and / or grease seals that can be acted upon with grease.

15. Bearing arrangement according to one of the preceding claims, wherein the rolling bearing (3) is designed as a single-row or multi-row roller bearing, in particular as a spherical roller bearing and / or the lubricant is a lubricating oil.

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