DE102012200440A1 - Bearing arrangement for rotatable supporting of shaft opposite to housing, has magnetic bearing and catch bearing that has roller bearing for transmitting axial or radial forces between shaft and housing - Google Patents

Abstract

The bearing arrangement (1) has a magnetic bearing (2) and a catch bearing (5) that has a roller bearing for transmitting axial or radial forces between a shaft (4) and a housing (3',3''). The catch bearing has a slide bearing that transmits additional forces between the shaft and the housing from a predetermined load of the roller bearing. The slide bearing has a slide bearing disk (13,14) connected with a bearing ring of the roller bearing in a torque-proof manner. the slide bearing disk has an annular body with a reinforcing rib (23).

Description

Field of the invention

The invention relates to a bearing assembly for rotatably supporting a shaft relative to a housing, with at least one magnetic bearing and a fishing camp, the fishing camp comprising a rolling bearing for transmitting axial and / or radial forces between the shaft and the housing.

Such a bearing assembly is for example from the DE 10 2009 022 835 B3 known. The non-contact bearing between shaft and housing providing magnetic bearing is preferably used due to the freedom from friction at very fast rotating waves. The task of the backup bearing is in case of failure of the magnetic bearing, eg due to interruption of the power supply, to prevent contact between the shaft and housing by at this moment designed as a rolling bearing ball bearing begins to transmit forces between the shaft and the housing ie to guide and center the shaft with respect to the housing. In normal operation of the magnetic bearing, however, no power transmission between the shaft and housing takes place by the fishing camp, for example by the fishing camp is radially and / or axially released.

In order to safely absorb the occurring in case of failure of the magnetic bearing and sometimes very large and shock loads of the backup bearing, so far a correspondingly large dimensions of the bearing is required - especially in very fast rotating waves with high weight.

Also known is the use of plain bearings as a backup warehouse, such as in the DE 10 2006 019 873 B3 disclosed. Although sliding bearings have the advantage over rolling bearings that much larger forces between the components to be stored can be transmitted. However, it was found that due to the specific operating conditions of a backup bearing a very high wear between the friction surfaces of the sliding bearing occurs. A sliding bearing used as a catch bearing can therefore often absorb only a few failures of the magnetic bearing before the life of the sliding bearing is reached.

Object of the invention

The invention has for its object to provide a bearing assembly for rotatably supporting a shaft relative to a housing, wherein the bearing assembly has at least one magnetic bearing and a backup bearing in the form of a rolling bearing, and wherein the bearing assembly has a compact structure and is characterized by a long service life and easy and inexpensive to manufacture.

Summary of the invention

This object is achieved by the features of the independent claim. Accordingly, a generic bearing assembly is characterized in that the backup bearing further comprises a sliding bearing, wherein the sliding bearing transmits additional forces between the shaft and the housing from a predetermined load of the rolling bearing.

The invention is based on the finding that the fishing camp by two separate bearings, namely a rolling bearing and a plain bearing form. Both bearings can basically transmit forces between the shaft and the housing. Up to a predetermined, i. structurally determinable, load of the bearing are - as soon as the retainer begins to bear - forces between the shaft and the housing transmitted exclusively via the rolling bearing. From the beginning of the load of the backup bearing up to this predetermined load, the sliding bearing thus transmits no forces. Only from the predetermined load, the sliding bearing additionally begins to transmit forces between the shaft and the housing.

In addition to the nominal load of backup bearings occurs mostly by the momentum on impact also a very short-term acting peak load due to surge. According to the invention, only the rolling bearing can absorb the forces for the (mostly temporally occurring) small to medium loads. The rolling bearing can therefore be made relatively compact, so that a small space is necessary and a low-cost rolling bearings can be used. The peak loads are additionally taken over by the sliding bearing, which thus protects the rolling bearing against excessive load. Due to the consequently very short operating times of the plain bearing, this - and thus the entire fishing camp - has a long service life.

It is conceivable that the sliding bearing can transfer forces indirectly (for example via components of the rolling bearing) or directly between the shaft and the housing.

Further advantages and features emerge from the dependent claims.

According to one embodiment, it is provided that the rolling bearing and the sliding bearing forces between the shaft and the housing in the Can transmit substantially the same direction. In particular, the roller bearing and the slide bearing may be thrust bearings, so that the safety bearing is an axial bearing.

According to one embodiment, it is provided that the slide bearing can transmit forces between the shaft and the housing via a first sliding surface and a second sliding surface and that in the unloaded state of the backup bearing between the first sliding surface and the second sliding surface there is a gap whose gap dimension in the unloaded state of the backup bearing corresponds to the amount of deflection of the rolling elements of the rolling bearing due to a predetermined elastic deformation of the rolling elements under load, so that from the occurrence of the predetermined elastic deformation of the rolling elements, a power transmission between the shaft and the housing additionally via the sliding bearing. The predetermined, i. structurally fixed, elastic deformation or deflection of the rolling elements corresponds to that deformation or deflection resulting due to the predetermined load of the bearing.

In principle, the sliding bearing can be integrated in the rolling bearing or else be formed separately from the rolling bearing. It is conceivable, in particular, that the sliding bearing and the roller bearing form a captive structural unit and can be mounted as such. According to one embodiment, it is provided that the sliding bearing has a front bearing with a first bearing ring of the bearing substantially non-rotatably connected plain bearing disk and that the plain bearing disc forms the gap with an end face of a second bearing ring of the rolling bearing. The first and the second bearing ring can be formed by an outer ring or an inner ring, said outer ring and inner ring may be present as a permanent components or may be formed in the sense of direct storage on connection structures. Such a design of the sliding bearing by a separate plain bearing disc has the advantage that they can be connected to conventional, in particular standardized rolling bearings, and thus results in a particularly simple and inexpensive construction.

An increase in the rigidity of the sliding bearing and thus an improved guidance of the shaft relative to the housing results if the sliding bearing disc has a circular ring body with at least one reinforcing rib. It is conceivable that the reinforcing rib protrudes axially from the circular ring body. If two or more reinforcing ribs are provided, they can project axially from the circular ring body on both sides. The reinforcing rib can also bring about an improvement in the sealing effect by the plain bearing disk, if the plain bearing disk is intended to seal the rolling bearing.

According to one embodiment, it is provided that the slide bearing disc is positively and / or non-positively and / or cohesively connected to the first bearing ring rotationally fixed. In the case of traction, short-term slippage for load limitation can also be permitted. The plain bearing disc consists of a separate component. The plain bearing disc may consist of a metallic or non-metallic material (in particular ceramic or plastic) and optionally have a coating.

According to one embodiment, it is provided that the plain bearing disk enables a sealing of the rolling bearing.

According to one embodiment, it is provided that the rolling bearing is a double-row angular contact ball bearing pair in an X arrangement. It is possible in particular that the fishing camp has a second slide bearing and that the two slide bearings can transmit forces in opposite directions, in particular in opposite axial directions, between the shaft and the housing.

Brief description of the drawings

The invention will be described in more detail below with reference to the accompanying drawings. Show

1 an embodiment of a bearing assembly according to the invention and

2 a plain bearing disc for use in a bearing arrangement according to the invention.

Detailed description of the drawing

1 shows an embodiment of a bearing assembly according to the invention 1 for rotatably supporting a shaft 4 opposite a housing 3 ' . 3 '' , Shown is the upper half of the axis of rotation 26 the bearing arrangement 1 comprehensive axial section.

The bearing assembly comprises a - schematically illustrated - magnetic bearing 2 , as well as a fishing camp 5 , The fishing camp 5 comprises a rolling bearing in the form of a double-row angular contact ball bearing pair in X arrangement.

The inner rings 6 . 7 of the rolling bearing are opposite the shaft 4 through a first gap 8th radially released. Through a second gap 9 and a third gap 10 are the inner ring 6 . 7 opposite a ring sitting on the shaft 11 or one shaft shoulder 12 axially released. In normal operation of the magnetic bearing 2 contact the inner rings 6 . 7 the wave 4 not, so no power transmission between shaft 4 and housing 3 through the rolling bearing. When the magnetic bearing 2 However, for example, due to an interruption of the power supply fails, the fishing camp begins 5 by means of the rolling bearing forces between the shaft 4 and the housing 3 transferred to. In particular, this occurring at the beginning shock loads are by a sliding bearing in the fishing camp 5 recorded by the sliding bearing from a predetermined load of the bearing additional forces between the shaft 4 and the housing 3 transfers.

In this embodiment, two plain bearings are provided, each slide bearing a plain bearing disc 13 . 14 which is formed by a circular ring body.

Each plain bearing disc 13 . 14 is with a first bearing ring, namely in this case an outer ring 15 . 16 , connected substantially rotatably. A substantially non-rotatable connection comprises in addition to a completely non-rotatable connection and frictional connections, the minimum rotation between plain bearing disc 13 . 14 and outer ring 15 . 16 allow.

The plain bearing washers 13 . 14 are frontally with the outer rings 15 . 16 connected, ie the plain bearing washers 13 . 14 lie on end faces 17 . 18 the outer rings 15 . 16 at. Each plain bearing disc 13 . 14 extends radially beyond an end face 19 . 20 of the respective inner ring 6 . 7 (second bearing ring) and forms opposite this end face 19 . 20 a gap 21 . 22 , This gap 21 . 22 Is dimensioned such that a (axially dimensioned in this embodiment) gap dimension in the unloaded state of the backup bearing corresponds to the amount of deflection of the rolling elements of the rolling bearing due to a predetermined elastic deformation of the rolling elements under load, so that from the occurrence of the predetermined elastic deformation of the rolling elements a Power transmission between the shaft and the housing additionally takes place via the sliding bearing.

The plain bearing disc 13 has an axially extending reinforcing rib 23 on the one hand, the rigidity of the plain bearing disc 13 increases and on the other hand an improved sealing effect through the plain bearing disc 13 allows.

The plain bearing disc 14 has a rectangular cross-sectional profile. The corresponding gap 22 to the inner ring 7 is formed by the fact that the inner ring 7 axially shorter than the associated outer ring 16 ,

The plain bearing disc 13 whereas, at the radial position, the overlap of the inner ring is indicated 6 a smaller axial extent, as at the radial overlap of the outer ring 15 , so that the gap 21 also with an angular contact ball bearing with inner ring 6 and outer ring 15 of the same axial extension forms. This has the advantage that a standard bearing can be used.

The housing 3 ' . 3 '' consists of a cup-shaped housing part 3 ' , in which the plain bearing disc 13 , the rolling bearing and the plain bearing disc 14 can be used and with a cover-shaped housing part 3 '' by means of screw connections 24 fixed, ie clamped, can be.

2 shows a plain bearing disc 25 for use in a bearing assembly according to the invention 1 , As can be seen, the plain bearing disc 25 two reinforcing ribs 23 on the axially on both sides of the plain bearing disc 25 protrude.

LIST OF REFERENCE NUMBERS

1

 bearing arrangement

2

 magnetic bearings

3

 casing

4

 wave

5

 safety bearing

6

 inner ring

7

 inner ring

8th

 first gap

9

 second gap

10

 third gap

11

 ring

12

 shaft shoulder

13

 slide bearing disk

14

 slide bearing disk

15

 outer ring

16

 outer ring

17

Front side of the outer ring 15

18

Front side of the outer ring 16

19

Front side of the inner ring 6

20

Front side of the inner ring 7

21

 gap

22

 gap

23

 reinforcing rib

24

 screw

25

 slide bearing disk

26

 axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009022835 B3 [0002]
• DE 102006019873 B3 [0004]

Claims (10)

Bearing arrangement ( 1 ) for rotatably supporting a shaft ( 4 ) with respect to a housing ( 3 ' . 3 '' ), with at least one magnetic bearing ( 2 ) and a fishing camp ( 5 ), the fishing camp ( 5 ) comprising a rolling bearing for transmitting axial and / or radial forces between the shaft ( 4 ) and the housing ( 3 ' . 3 '' ), characterized in that the fishing camp ( 5 ) further comprises a sliding bearing, wherein the sliding bearing from a predetermined load of the bearing additionally forces between the shaft ( 4 ) and the housing transmits. Bearing arrangement ( 1 ) according to claim 1, characterized in that the rolling bearing and the sliding bearing forces between the shaft ( 4 ) and the housing ( 3 ' . 3 '' ) can transmit in substantially the same direction. Bearing arrangement ( 1 ) according to claim 1 or 2, characterized in that the sliding bearing via a first sliding surface and a second sliding surface forces between the shaft ( 4 ) and the housing ( 3 ' . 3 '' ) and that in the unloaded condition of the backup bearing ( 5 ) between the first sliding surface and the second sliding surface a gap ( 21 . 22 ) whose clearance in the unloaded state of the backup bearing ( 5 ) the amount of deflection of the rolling elements ( 27 ) of the rolling bearing due to a predetermined elastic deformation of the rolling elements ( 27 ) under load, so that from the occurrence of the predetermined elastic deformation of the rolling elements ( 27 ) a power transmission between the shaft ( 4 ) and the housing ( 3 ' . 3 '' ) additionally takes place via the plain bearing. Bearing arrangement ( 1 ) according to claim 3, characterized in that the sliding bearing a front side with a first bearing ring of the rolling bearing rotatably connected plain bearing disc ( 13 . 14 ) and that the plain bearing disc ( 13 . 14 ) with a front side ( 19 . 20 ) of a second bearing ring of the rolling bearing forms the gap. Bearing arrangement ( 1 ) according to claim 4, characterized in that the plain bearing disc ( 13 ) a circular ring body with at least one reinforcing rib ( 23 ) having. Bearing arrangement ( 1 ) according to claim 5, characterized in that the reinforcing rib ( 23 ) axially protrudes from the circular ring body. Bearing arrangement ( 1 ) according to one of claims 4 to 6, characterized in that the plain bearing disc ( 13 . 14 ) is positively and / or non-positively and / or materially connected to the first bearing ring substantially rotatably connected. Bearing arrangement ( 1 ) according to one of the preceding claims, characterized in that the rolling bearing is a double-row angular contact ball bearing pair in. Bearing arrangement ( 1 ) according to one of the preceding claims, characterized in that the plain bearing disc ( 13 . 14 ) allows a seal of the rolling bearing. Bearing arrangement ( 1 ) according to one of the preceding claims, characterized in that the fishing camp ( 5 ) a second sliding bearing ( 14 ) and that the two plain bearings ( 13 . 14 ) Forces in opposite directions, especially in opposite axial directions, between the shaft ( 4 ) and the housing ( 3 ' . 3 '' ) can transmit.

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